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abea62351bad2f5bac0b2f900085cb273aedd5645a8cf3504c54128a7e4b7b28
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from sympy.utilities.pytest import ignore_warnings
from sympy.utilities.exceptions import SymPyDeprecationWarning
with ignore_warnings(SymPyDeprecationWarning):
from sympy.matrices.densetools import eye
from sympy.matrices.densearith import add, sub, mulmatmat, mulmatscaler
from sympy import ZZ
def test_add():
a = [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
b = [[ZZ(5), ZZ(4), ZZ(9)], [ZZ(3), ZZ(7), ZZ(1)], [ZZ(12), ZZ(13), ZZ(14)]]
c = [[ZZ(12)], [ZZ(17)], [ZZ(21)]]
d = [[ZZ(3)], [ZZ(4)], [ZZ(5)]]
e = [[ZZ(12), ZZ(78)], [ZZ(56), ZZ(79)]]
f = [[ZZ.zero, ZZ.zero], [ZZ.zero, ZZ.zero]]
assert add(a, b, ZZ) == [[ZZ(8), ZZ(11), ZZ(13)], [ZZ(5), ZZ(11), ZZ(6)], [ZZ(18), ZZ(15), ZZ(17)]]
assert add(c, d, ZZ) == [[ZZ(15)], [ZZ(21)], [ZZ(26)]]
assert add(e, f, ZZ) == e
def test_sub():
a = [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
b = [[ZZ(5), ZZ(4), ZZ(9)], [ZZ(3), ZZ(7), ZZ(1)], [ZZ(12), ZZ(13), ZZ(14)]]
c = [[ZZ(12)], [ZZ(17)], [ZZ(21)]]
d = [[ZZ(3)], [ZZ(4)], [ZZ(5)]]
e = [[ZZ(12), ZZ(78)], [ZZ(56), ZZ(79)]]
f = [[ZZ.zero, ZZ.zero], [ZZ.zero, ZZ.zero]]
assert sub(a, b, ZZ) == [[ZZ(-2), ZZ(3), ZZ(-5)], [ZZ(-1), ZZ(-3), ZZ(4)], [ZZ(-6), ZZ(-11), ZZ(-11)]]
assert sub(c, d, ZZ) == [[ZZ(9)], [ZZ(13)], [ZZ(16)]]
assert sub(e, f, ZZ) == e
def test_mulmatmat():
a = [[ZZ(3), ZZ(4)], [ZZ(5), ZZ(6)]]
b = [[ZZ(1), ZZ(2)], [ZZ(7), ZZ(8)]]
c = eye(2, ZZ)
d = [[ZZ(6)], [ZZ(7)]]
assert mulmatmat(a, b, ZZ) == [[ZZ(31), ZZ(38)], [ZZ(47), ZZ(58)]]
assert mulmatmat(b, d, ZZ) == [[ZZ(20)], [ZZ(98)]]
def test_mulmatscaler():
a = eye(3, ZZ)
b = [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
assert mulmatscaler(a, ZZ(4), ZZ) == [[ZZ(4), ZZ(0), ZZ(0)], [ZZ(0), ZZ(4), ZZ(0)], [ZZ(0), ZZ(0), ZZ(4)]]
assert mulmatscaler(b, ZZ(1), ZZ) == [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
|
6c0cd3fbff98f3433bd55979b68f3316bcc05a70c137c126fa2290623dea2e30
|
from sympy.utilities.pytest import ignore_warnings
from sympy.utilities.exceptions import SymPyDeprecationWarning
with ignore_warnings(SymPyDeprecationWarning):
from sympy.matrices.densetools import trace, transpose, eye
from sympy import ZZ
def test_trace():
a = [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
b = eye(2, ZZ)
assert trace(a, ZZ) == ZZ(10)
assert trace(b, ZZ) == ZZ(2)
def test_transpose():
a = [[ZZ(3), ZZ(7), ZZ(4)], [ZZ(2), ZZ(4), ZZ(5)], [ZZ(6), ZZ(2), ZZ(3)]]
b = eye(4, ZZ)
assert transpose(a, ZZ) == ([[ZZ(3), ZZ(2), ZZ(6)], [ZZ(7), ZZ(4), ZZ(2)], [ZZ(4), ZZ(5), ZZ(3)]])
assert transpose(b, ZZ) == b
|
4cef4f30d34792f83a7f0a213c61f87e07e786fbcef6de018bdcf0eb73bdd240
|
import random
from sympy import (
Abs, Add, E, Float, I, Integer, Max, Min, N, Poly, Pow, PurePoly, Rational,
S, Symbol, cos, exp, expand_mul, oo, pi, signsimp, simplify, sin, sqrt, symbols,
sympify, trigsimp, tan, sstr, diff, Function)
from sympy.matrices.matrices import (ShapeError, MatrixError,
NonSquareMatrixError, DeferredVector, _find_reasonable_pivot_naive,
_simplify)
from sympy.matrices import (
GramSchmidt, ImmutableMatrix, ImmutableSparseMatrix, Matrix,
SparseMatrix, casoratian, diag, eye, hessian,
matrix_multiply_elementwise, ones, randMatrix, rot_axis1, rot_axis2,
rot_axis3, wronskian, zeros, MutableDenseMatrix, ImmutableDenseMatrix)
from sympy.core.compatibility import long, iterable, range, Hashable
from sympy.core import Tuple
from sympy.utilities.iterables import flatten, capture
from sympy.utilities.pytest import raises, XFAIL, slow, skip, warns_deprecated_sympy
from sympy.solvers import solve
from sympy.assumptions import Q
from sympy.tensor.array import Array
from sympy.abc import a, b, c, d, x, y, z, t
# don't re-order this list
classes = (Matrix, SparseMatrix, ImmutableMatrix, ImmutableSparseMatrix)
def test_args():
for c, cls in enumerate(classes):
m = cls.zeros(3, 2)
# all should give back the same type of arguments, e.g. ints for shape
assert m.shape == (3, 2) and all(type(i) is int for i in m.shape)
assert m.rows == 3 and type(m.rows) is int
assert m.cols == 2 and type(m.cols) is int
if not c % 2:
assert type(m._mat) in (list, tuple, Tuple)
else:
assert type(m._smat) is dict
def test_division():
v = Matrix(1, 2, [x, y])
assert v.__div__(z) == Matrix(1, 2, [x/z, y/z])
assert v.__truediv__(z) == Matrix(1, 2, [x/z, y/z])
assert v/z == Matrix(1, 2, [x/z, y/z])
def test_sum():
m = Matrix([[1, 2, 3], [x, y, x], [2*y, -50, z*x]])
assert m + m == Matrix([[2, 4, 6], [2*x, 2*y, 2*x], [4*y, -100, 2*z*x]])
n = Matrix(1, 2, [1, 2])
raises(ShapeError, lambda: m + n)
def test_abs():
m = Matrix(1, 2, [-3, x])
n = Matrix(1, 2, [3, Abs(x)])
assert abs(m) == n
def test_addition():
a = Matrix((
(1, 2),
(3, 1),
))
b = Matrix((
(1, 2),
(3, 0),
))
assert a + b == a.add(b) == Matrix([[2, 4], [6, 1]])
def test_fancy_index_matrix():
for M in (Matrix, SparseMatrix):
a = M(3, 3, range(9))
assert a == a[:, :]
assert a[1, :] == Matrix(1, 3, [3, 4, 5])
assert a[:, 1] == Matrix([1, 4, 7])
assert a[[0, 1], :] == Matrix([[0, 1, 2], [3, 4, 5]])
assert a[[0, 1], 2] == a[[0, 1], [2]]
assert a[2, [0, 1]] == a[[2], [0, 1]]
assert a[:, [0, 1]] == Matrix([[0, 1], [3, 4], [6, 7]])
assert a[0, 0] == 0
assert a[0:2, :] == Matrix([[0, 1, 2], [3, 4, 5]])
assert a[:, 0:2] == Matrix([[0, 1], [3, 4], [6, 7]])
assert a[::2, 1] == a[[0, 2], 1]
assert a[1, ::2] == a[1, [0, 2]]
a = M(3, 3, range(9))
assert a[[0, 2, 1, 2, 1], :] == Matrix([
[0, 1, 2],
[6, 7, 8],
[3, 4, 5],
[6, 7, 8],
[3, 4, 5]])
assert a[:, [0,2,1,2,1]] == Matrix([
[0, 2, 1, 2, 1],
[3, 5, 4, 5, 4],
[6, 8, 7, 8, 7]])
a = SparseMatrix.zeros(3)
a[1, 2] = 2
a[0, 1] = 3
a[2, 0] = 4
assert a.extract([1, 1], [2]) == Matrix([
[2],
[2]])
assert a.extract([1, 0], [2, 2, 2]) == Matrix([
[2, 2, 2],
[0, 0, 0]])
assert a.extract([1, 0, 1, 2], [2, 0, 1, 0]) == Matrix([
[2, 0, 0, 0],
[0, 0, 3, 0],
[2, 0, 0, 0],
[0, 4, 0, 4]])
def test_multiplication():
a = Matrix((
(1, 2),
(3, 1),
(0, 6),
))
b = Matrix((
(1, 2),
(3, 0),
))
c = a*b
assert c[0, 0] == 7
assert c[0, 1] == 2
assert c[1, 0] == 6
assert c[1, 1] == 6
assert c[2, 0] == 18
assert c[2, 1] == 0
try:
eval('c = a @ b')
except SyntaxError:
pass
else:
assert c[0, 0] == 7
assert c[0, 1] == 2
assert c[1, 0] == 6
assert c[1, 1] == 6
assert c[2, 0] == 18
assert c[2, 1] == 0
h = matrix_multiply_elementwise(a, c)
assert h == a.multiply_elementwise(c)
assert h[0, 0] == 7
assert h[0, 1] == 4
assert h[1, 0] == 18
assert h[1, 1] == 6
assert h[2, 0] == 0
assert h[2, 1] == 0
raises(ShapeError, lambda: matrix_multiply_elementwise(a, b))
c = b * Symbol("x")
assert isinstance(c, Matrix)
assert c[0, 0] == x
assert c[0, 1] == 2*x
assert c[1, 0] == 3*x
assert c[1, 1] == 0
c2 = x * b
assert c == c2
c = 5 * b
assert isinstance(c, Matrix)
assert c[0, 0] == 5
assert c[0, 1] == 2*5
assert c[1, 0] == 3*5
assert c[1, 1] == 0
try:
eval('c = 5 @ b')
except SyntaxError:
pass
else:
assert isinstance(c, Matrix)
assert c[0, 0] == 5
assert c[0, 1] == 2*5
assert c[1, 0] == 3*5
assert c[1, 1] == 0
def test_power():
raises(NonSquareMatrixError, lambda: Matrix((1, 2))**2)
R = Rational
A = Matrix([[2, 3], [4, 5]])
assert (A**-3)[:] == [R(-269)/8, R(153)/8, R(51)/2, R(-29)/2]
assert (A**5)[:] == [6140, 8097, 10796, 14237]
A = Matrix([[2, 1, 3], [4, 2, 4], [6, 12, 1]])
assert (A**3)[:] == [290, 262, 251, 448, 440, 368, 702, 954, 433]
assert A**0 == eye(3)
assert A**1 == A
assert (Matrix([[2]]) ** 100)[0, 0] == 2**100
assert eye(2)**10000000 == eye(2)
assert Matrix([[1, 2], [3, 4]])**Integer(2) == Matrix([[7, 10], [15, 22]])
A = Matrix([[33, 24], [48, 57]])
assert (A**(S(1)/2))[:] == [5, 2, 4, 7]
A = Matrix([[0, 4], [-1, 5]])
assert (A**(S(1)/2))**2 == A
assert Matrix([[1, 0], [1, 1]])**(S(1)/2) == Matrix([[1, 0], [S.Half, 1]])
assert Matrix([[1, 0], [1, 1]])**0.5 == Matrix([[1.0, 0], [0.5, 1.0]])
from sympy.abc import a, b, n
assert Matrix([[1, a], [0, 1]])**n == Matrix([[1, a*n], [0, 1]])
assert Matrix([[b, a], [0, b]])**n == Matrix([[b**n, a*b**(n-1)*n], [0, b**n]])
assert Matrix([[a, 1, 0], [0, a, 1], [0, 0, a]])**n == Matrix([
[a**n, a**(n-1)*n, a**(n-2)*(n-1)*n/2],
[0, a**n, a**(n-1)*n],
[0, 0, a**n]])
assert Matrix([[a, 1, 0], [0, a, 0], [0, 0, b]])**n == Matrix([
[a**n, a**(n-1)*n, 0],
[0, a**n, 0],
[0, 0, b**n]])
A = Matrix([[1, 0], [1, 7]])
assert A._matrix_pow_by_jordan_blocks(3) == A._eval_pow_by_recursion(3)
A = Matrix([[2]])
assert A**10 == Matrix([[2**10]]) == A._matrix_pow_by_jordan_blocks(10) == \
A._eval_pow_by_recursion(10)
# testing a matrix that cannot be jordan blocked issue 11766
m = Matrix([[3, 0, 0, 0, -3], [0, -3, -3, 0, 3], [0, 3, 0, 3, 0], [0, 0, 3, 0, 3], [3, 0, 0, 3, 0]])
raises(MatrixError, lambda: m._matrix_pow_by_jordan_blocks(10))
# test issue 11964
raises(ValueError, lambda: Matrix([[1, 1], [3, 3]])._matrix_pow_by_jordan_blocks(-10))
A = Matrix([[0, 1, 0], [0, 0, 1], [0, 0, 0]]) # Nilpotent jordan block size 3
assert A**10.0 == Matrix([[0, 0, 0], [0, 0, 0], [0, 0, 0]])
raises(ValueError, lambda: A**2.1)
raises(ValueError, lambda: A**(S(3)/2))
A = Matrix([[8, 1], [3, 2]])
assert A**10.0 == Matrix([[1760744107, 272388050], [817164150, 126415807]])
A = Matrix([[0, 0, 1], [0, 0, 1], [0, 0, 1]]) # Nilpotent jordan block size 1
assert A**10.2 == Matrix([[0, 0, 1], [0, 0, 1], [0, 0, 1]])
A = Matrix([[0, 1, 0], [0, 0, 1], [0, 0, 1]]) # Nilpotent jordan block size 2
assert A**10.0 == Matrix([[0, 0, 1], [0, 0, 1], [0, 0, 1]])
n = Symbol('n', integer=True)
raises(ValueError, lambda: A**n)
n = Symbol('n', integer=True, nonnegative=True)
raises(ValueError, lambda: A**n)
assert A**(n + 2) == Matrix([[0, 0, 1], [0, 0, 1], [0, 0, 1]])
raises(ValueError, lambda: A**(S(3)/2))
A = Matrix([[0, 0, 1], [3, 0, 1], [4, 3, 1]])
assert A**5.0 == Matrix([[168, 72, 89], [291, 144, 161], [572, 267, 329]])
assert A**5.0 == A**5
def test_creation():
raises(ValueError, lambda: Matrix(5, 5, range(20)))
raises(ValueError, lambda: Matrix(5, -1, []))
raises(IndexError, lambda: Matrix((1, 2))[2])
with raises(IndexError):
Matrix((1, 2))[1:2] = 5
with raises(IndexError):
Matrix((1, 2))[3] = 5
assert Matrix() == Matrix([]) == Matrix([[]]) == Matrix(0, 0, [])
a = Matrix([[x, 0], [0, 0]])
m = a
assert m.cols == m.rows
assert m.cols == 2
assert m[:] == [x, 0, 0, 0]
b = Matrix(2, 2, [x, 0, 0, 0])
m = b
assert m.cols == m.rows
assert m.cols == 2
assert m[:] == [x, 0, 0, 0]
assert a == b
assert Matrix(b) == b
c = Matrix((
Matrix((
(1, 2, 3),
(4, 5, 6)
)),
(7, 8, 9)
))
assert c.cols == 3
assert c.rows == 3
assert c[:] == [1, 2, 3, 4, 5, 6, 7, 8, 9]
assert Matrix(eye(2)) == eye(2)
assert ImmutableMatrix(ImmutableMatrix(eye(2))) == ImmutableMatrix(eye(2))
assert ImmutableMatrix(c) == c.as_immutable()
assert Matrix(ImmutableMatrix(c)) == ImmutableMatrix(c).as_mutable()
assert c is not Matrix(c)
def test_tolist():
lst = [[S.One, S.Half, x*y, S.Zero], [x, y, z, x**2], [y, -S.One, z*x, 3]]
m = Matrix(lst)
assert m.tolist() == lst
def test_as_mutable():
assert zeros(0, 3).as_mutable() == zeros(0, 3)
assert zeros(0, 3).as_immutable() == ImmutableMatrix(zeros(0, 3))
assert zeros(3, 0).as_immutable() == ImmutableMatrix(zeros(3, 0))
def test_determinant():
for M in [Matrix(), Matrix([[1]])]:
assert (
M.det() ==
M._eval_det_bareiss() ==
M._eval_det_berkowitz() ==
M._eval_det_lu() ==
1)
M = Matrix(( (-3, 2),
( 8, -5) ))
assert M.det(method="bareiss") == -1
assert M.det(method="berkowitz") == -1
assert M.det(method="lu") == -1
M = Matrix(( (x, 1),
(y, 2*y) ))
assert M.det(method="bareiss") == 2*x*y - y
assert M.det(method="berkowitz") == 2*x*y - y
assert M.det(method="lu") == 2*x*y - y
M = Matrix(( (1, 1, 1),
(1, 2, 3),
(1, 3, 6) ))
assert M.det(method="bareiss") == 1
assert M.det(method="berkowitz") == 1
assert M.det(method="lu") == 1
M = Matrix(( ( 3, -2, 0, 5),
(-2, 1, -2, 2),
( 0, -2, 5, 0),
( 5, 0, 3, 4) ))
assert M.det(method="bareiss") == -289
assert M.det(method="berkowitz") == -289
assert M.det(method="lu") == -289
M = Matrix(( ( 1, 2, 3, 4),
( 5, 6, 7, 8),
( 9, 10, 11, 12),
(13, 14, 15, 16) ))
assert M.det(method="bareiss") == 0
assert M.det(method="berkowitz") == 0
assert M.det(method="lu") == 0
M = Matrix(( (3, 2, 0, 0, 0),
(0, 3, 2, 0, 0),
(0, 0, 3, 2, 0),
(0, 0, 0, 3, 2),
(2, 0, 0, 0, 3) ))
assert M.det(method="bareiss") == 275
assert M.det(method="berkowitz") == 275
assert M.det(method="lu") == 275
M = Matrix(( (1, 0, 1, 2, 12),
(2, 0, 1, 1, 4),
(2, 1, 1, -1, 3),
(3, 2, -1, 1, 8),
(1, 1, 1, 0, 6) ))
assert M.det(method="bareiss") == -55
assert M.det(method="berkowitz") == -55
assert M.det(method="lu") == -55
M = Matrix(( (-5, 2, 3, 4, 5),
( 1, -4, 3, 4, 5),
( 1, 2, -3, 4, 5),
( 1, 2, 3, -2, 5),
( 1, 2, 3, 4, -1) ))
assert M.det(method="bareiss") == 11664
assert M.det(method="berkowitz") == 11664
assert M.det(method="lu") == 11664
M = Matrix(( ( 2, 7, -1, 3, 2),
( 0, 0, 1, 0, 1),
(-2, 0, 7, 0, 2),
(-3, -2, 4, 5, 3),
( 1, 0, 0, 0, 1) ))
assert M.det(method="bareiss") == 123
assert M.det(method="berkowitz") == 123
assert M.det(method="lu") == 123
M = Matrix(( (x, y, z),
(1, 0, 0),
(y, z, x) ))
assert M.det(method="bareiss") == z**2 - x*y
assert M.det(method="berkowitz") == z**2 - x*y
assert M.det(method="lu") == z**2 - x*y
# issue 13835
a = symbols('a')
M = lambda n: Matrix([[i + a*j for i in range(n)]
for j in range(n)])
assert M(5).det() == 0
assert M(6).det() == 0
assert M(7).det() == 0
def test_slicing():
m0 = eye(4)
assert m0[:3, :3] == eye(3)
assert m0[2:4, 0:2] == zeros(2)
m1 = Matrix(3, 3, lambda i, j: i + j)
assert m1[0, :] == Matrix(1, 3, (0, 1, 2))
assert m1[1:3, 1] == Matrix(2, 1, (2, 3))
m2 = Matrix([[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15]])
assert m2[:, -1] == Matrix(4, 1, [3, 7, 11, 15])
assert m2[-2:, :] == Matrix([[8, 9, 10, 11], [12, 13, 14, 15]])
def test_submatrix_assignment():
m = zeros(4)
m[2:4, 2:4] = eye(2)
assert m == Matrix(((0, 0, 0, 0),
(0, 0, 0, 0),
(0, 0, 1, 0),
(0, 0, 0, 1)))
m[:2, :2] = eye(2)
assert m == eye(4)
m[:, 0] = Matrix(4, 1, (1, 2, 3, 4))
assert m == Matrix(((1, 0, 0, 0),
(2, 1, 0, 0),
(3, 0, 1, 0),
(4, 0, 0, 1)))
m[:, :] = zeros(4)
assert m == zeros(4)
m[:, :] = [(1, 2, 3, 4), (5, 6, 7, 8), (9, 10, 11, 12), (13, 14, 15, 16)]
assert m == Matrix(((1, 2, 3, 4),
(5, 6, 7, 8),
(9, 10, 11, 12),
(13, 14, 15, 16)))
m[:2, 0] = [0, 0]
assert m == Matrix(((0, 2, 3, 4),
(0, 6, 7, 8),
(9, 10, 11, 12),
(13, 14, 15, 16)))
def test_extract():
m = Matrix(4, 3, lambda i, j: i*3 + j)
assert m.extract([0, 1, 3], [0, 1]) == Matrix(3, 2, [0, 1, 3, 4, 9, 10])
assert m.extract([0, 3], [0, 0, 2]) == Matrix(2, 3, [0, 0, 2, 9, 9, 11])
assert m.extract(range(4), range(3)) == m
raises(IndexError, lambda: m.extract([4], [0]))
raises(IndexError, lambda: m.extract([0], [3]))
def test_reshape():
m0 = eye(3)
assert m0.reshape(1, 9) == Matrix(1, 9, (1, 0, 0, 0, 1, 0, 0, 0, 1))
m1 = Matrix(3, 4, lambda i, j: i + j)
assert m1.reshape(
4, 3) == Matrix(((0, 1, 2), (3, 1, 2), (3, 4, 2), (3, 4, 5)))
assert m1.reshape(2, 6) == Matrix(((0, 1, 2, 3, 1, 2), (3, 4, 2, 3, 4, 5)))
def test_applyfunc():
m0 = eye(3)
assert m0.applyfunc(lambda x: 2*x) == eye(3)*2
assert m0.applyfunc(lambda x: 0) == zeros(3)
def test_expand():
m0 = Matrix([[x*(x + y), 2], [((x + y)*y)*x, x*(y + x*(x + y))]])
# Test if expand() returns a matrix
m1 = m0.expand()
assert m1 == Matrix(
[[x*y + x**2, 2], [x*y**2 + y*x**2, x*y + y*x**2 + x**3]])
a = Symbol('a', real=True)
assert Matrix([exp(I*a)]).expand(complex=True) == \
Matrix([cos(a) + I*sin(a)])
assert Matrix([[0, 1, 2], [0, 0, -1], [0, 0, 0]]).exp() == Matrix([
[1, 1, Rational(3, 2)],
[0, 1, -1],
[0, 0, 1]]
)
def test_refine():
m0 = Matrix([[Abs(x)**2, sqrt(x**2)],
[sqrt(x**2)*Abs(y)**2, sqrt(y**2)*Abs(x)**2]])
m1 = m0.refine(Q.real(x) & Q.real(y))
assert m1 == Matrix([[x**2, Abs(x)], [y**2*Abs(x), x**2*Abs(y)]])
m1 = m0.refine(Q.positive(x) & Q.positive(y))
assert m1 == Matrix([[x**2, x], [x*y**2, x**2*y]])
m1 = m0.refine(Q.negative(x) & Q.negative(y))
assert m1 == Matrix([[x**2, -x], [-x*y**2, -x**2*y]])
def test_random():
M = randMatrix(3, 3)
M = randMatrix(3, 3, seed=3)
assert M == randMatrix(3, 3, seed=3)
M = randMatrix(3, 4, 0, 150)
M = randMatrix(3, seed=4, symmetric=True)
assert M == randMatrix(3, seed=4, symmetric=True)
S = M.copy()
S.simplify()
assert S == M # doesn't fail when elements are Numbers, not int
rng = random.Random(4)
assert M == randMatrix(3, symmetric=True, prng=rng)
# Ensure symmetry
for size in (10, 11): # Test odd and even
for percent in (100, 70, 30):
M = randMatrix(size, symmetric=True, percent=percent, prng=rng)
assert M == M.T
M = randMatrix(10, min=1, percent=70)
zero_count = 0
for i in range(M.shape[0]):
for j in range(M.shape[1]):
if M[i, j] == 0:
zero_count += 1
assert zero_count == 30
def test_LUdecomp():
testmat = Matrix([[0, 2, 5, 3],
[3, 3, 7, 4],
[8, 4, 0, 2],
[-2, 6, 3, 4]])
L, U, p = testmat.LUdecomposition()
assert L.is_lower
assert U.is_upper
assert (L*U).permute_rows(p, 'backward') - testmat == zeros(4)
testmat = Matrix([[6, -2, 7, 4],
[0, 3, 6, 7],
[1, -2, 7, 4],
[-9, 2, 6, 3]])
L, U, p = testmat.LUdecomposition()
assert L.is_lower
assert U.is_upper
assert (L*U).permute_rows(p, 'backward') - testmat == zeros(4)
# non-square
testmat = Matrix([[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[10, 11, 12]])
L, U, p = testmat.LUdecomposition(rankcheck=False)
assert L.is_lower
assert U.is_upper
assert (L*U).permute_rows(p, 'backward') - testmat == zeros(4, 3)
# square and singular
testmat = Matrix([[1, 2, 3],
[2, 4, 6],
[4, 5, 6]])
L, U, p = testmat.LUdecomposition(rankcheck=False)
assert L.is_lower
assert U.is_upper
assert (L*U).permute_rows(p, 'backward') - testmat == zeros(3)
M = Matrix(((1, x, 1), (2, y, 0), (y, 0, z)))
L, U, p = M.LUdecomposition()
assert L.is_lower
assert U.is_upper
assert (L*U).permute_rows(p, 'backward') - M == zeros(3)
mL = Matrix((
(1, 0, 0),
(2, 3, 0),
))
assert mL.is_lower is True
assert mL.is_upper is False
mU = Matrix((
(1, 2, 3),
(0, 4, 5),
))
assert mU.is_lower is False
assert mU.is_upper is True
# test FF LUdecomp
M = Matrix([[1, 3, 3],
[3, 2, 6],
[3, 2, 2]])
P, L, Dee, U = M.LUdecompositionFF()
assert P*M == L*Dee.inv()*U
M = Matrix([[1, 2, 3, 4],
[3, -1, 2, 3],
[3, 1, 3, -2],
[6, -1, 0, 2]])
P, L, Dee, U = M.LUdecompositionFF()
assert P*M == L*Dee.inv()*U
M = Matrix([[0, 0, 1],
[2, 3, 0],
[3, 1, 4]])
P, L, Dee, U = M.LUdecompositionFF()
assert P*M == L*Dee.inv()*U
def test_LUsolve():
A = Matrix([[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
x = Matrix(3, 1, [3, 7, 5])
b = A*x
soln = A.LUsolve(b)
assert soln == x
A = Matrix([[0, -1, 2],
[5, 10, 7],
[8, 3, 4]])
x = Matrix(3, 1, [-1, 2, 5])
b = A*x
soln = A.LUsolve(b)
assert soln == x
A = Matrix([[2, 1], [1, 0], [1, 0]]) # issue 14548
b = Matrix([3, 1, 1])
assert A.LUsolve(b) == Matrix([1, 1])
b = Matrix([3, 1, 2]) # inconsistent
raises(ValueError, lambda: A.LUsolve(b))
A = Matrix([[0, -1, 2],
[5, 10, 7],
[8, 3, 4],
[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
x = Matrix([2, 1, -4])
b = A*x
soln = A.LUsolve(b)
assert soln == x
A = Matrix([[0, -1, 2], [5, 10, 7]]) # underdetermined
x = Matrix([-1, 2, 0])
b = A*x
raises(NotImplementedError, lambda: A.LUsolve(b))
def test_QRsolve():
A = Matrix([[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
x = Matrix(3, 1, [3, 7, 5])
b = A*x
soln = A.QRsolve(b)
assert soln == x
x = Matrix([[1, 2], [3, 4], [5, 6]])
b = A*x
soln = A.QRsolve(b)
assert soln == x
A = Matrix([[0, -1, 2],
[5, 10, 7],
[8, 3, 4]])
x = Matrix(3, 1, [-1, 2, 5])
b = A*x
soln = A.QRsolve(b)
assert soln == x
x = Matrix([[7, 8], [9, 10], [11, 12]])
b = A*x
soln = A.QRsolve(b)
assert soln == x
def test_inverse():
A = eye(4)
assert A.inv() == eye(4)
assert A.inv(method="LU") == eye(4)
assert A.inv(method="ADJ") == eye(4)
A = Matrix([[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
Ainv = A.inv()
assert A*Ainv == eye(3)
assert A.inv(method="LU") == Ainv
assert A.inv(method="ADJ") == Ainv
# test that immutability is not a problem
cls = ImmutableMatrix
m = cls([[48, 49, 31],
[ 9, 71, 94],
[59, 28, 65]])
assert all(type(m.inv(s)) is cls for s in 'GE ADJ LU'.split())
cls = ImmutableSparseMatrix
m = cls([[48, 49, 31],
[ 9, 71, 94],
[59, 28, 65]])
assert all(type(m.inv(s)) is cls for s in 'CH LDL'.split())
def test_matrix_inverse_mod():
A = Matrix(2, 1, [1, 0])
raises(NonSquareMatrixError, lambda: A.inv_mod(2))
A = Matrix(2, 2, [1, 0, 0, 0])
raises(ValueError, lambda: A.inv_mod(2))
A = Matrix(2, 2, [1, 2, 3, 4])
Ai = Matrix(2, 2, [1, 1, 0, 1])
assert A.inv_mod(3) == Ai
A = Matrix(2, 2, [1, 0, 0, 1])
assert A.inv_mod(2) == A
A = Matrix(3, 3, [1, 2, 3, 4, 5, 6, 7, 8, 9])
raises(ValueError, lambda: A.inv_mod(5))
A = Matrix(3, 3, [5, 1, 3, 2, 6, 0, 2, 1, 1])
Ai = Matrix(3, 3, [6, 8, 0, 1, 5, 6, 5, 6, 4])
assert A.inv_mod(9) == Ai
A = Matrix(3, 3, [1, 6, -3, 4, 1, -5, 3, -5, 5])
Ai = Matrix(3, 3, [4, 3, 3, 1, 2, 5, 1, 5, 1])
assert A.inv_mod(6) == Ai
A = Matrix(3, 3, [1, 6, 1, 4, 1, 5, 3, 2, 5])
Ai = Matrix(3, 3, [6, 0, 3, 6, 6, 4, 1, 6, 1])
assert A.inv_mod(7) == Ai
def test_util():
R = Rational
v1 = Matrix(1, 3, [1, 2, 3])
v2 = Matrix(1, 3, [3, 4, 5])
assert v1.norm() == sqrt(14)
assert v1.project(v2) == Matrix(1, 3, [R(39)/25, R(52)/25, R(13)/5])
assert Matrix.zeros(1, 2) == Matrix(1, 2, [0, 0])
assert ones(1, 2) == Matrix(1, 2, [1, 1])
assert v1.copy() == v1
# cofactor
assert eye(3) == eye(3).cofactor_matrix()
test = Matrix([[1, 3, 2], [2, 6, 3], [2, 3, 6]])
assert test.cofactor_matrix() == \
Matrix([[27, -6, -6], [-12, 2, 3], [-3, 1, 0]])
test = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
assert test.cofactor_matrix() == \
Matrix([[-3, 6, -3], [6, -12, 6], [-3, 6, -3]])
def test_jacobian_hessian():
L = Matrix(1, 2, [x**2*y, 2*y**2 + x*y])
syms = [x, y]
assert L.jacobian(syms) == Matrix([[2*x*y, x**2], [y, 4*y + x]])
L = Matrix(1, 2, [x, x**2*y**3])
assert L.jacobian(syms) == Matrix([[1, 0], [2*x*y**3, x**2*3*y**2]])
f = x**2*y
syms = [x, y]
assert hessian(f, syms) == Matrix([[2*y, 2*x], [2*x, 0]])
f = x**2*y**3
assert hessian(f, syms) == \
Matrix([[2*y**3, 6*x*y**2], [6*x*y**2, 6*x**2*y]])
f = z + x*y**2
g = x**2 + 2*y**3
ans = Matrix([[0, 2*y],
[2*y, 2*x]])
assert ans == hessian(f, Matrix([x, y]))
assert ans == hessian(f, Matrix([x, y]).T)
assert hessian(f, (y, x), [g]) == Matrix([
[ 0, 6*y**2, 2*x],
[6*y**2, 2*x, 2*y],
[ 2*x, 2*y, 0]])
def test_QR():
A = Matrix([[1, 2], [2, 3]])
Q, S = A.QRdecomposition()
R = Rational
assert Q == Matrix([
[ 5**R(-1, 2), (R(2)/5)*(R(1)/5)**R(-1, 2)],
[2*5**R(-1, 2), (-R(1)/5)*(R(1)/5)**R(-1, 2)]])
assert S == Matrix([[5**R(1, 2), 8*5**R(-1, 2)], [0, (R(1)/5)**R(1, 2)]])
assert Q*S == A
assert Q.T * Q == eye(2)
A = Matrix([[1, 1, 1], [1, 1, 3], [2, 3, 4]])
Q, R = A.QRdecomposition()
assert Q.T * Q == eye(Q.cols)
assert R.is_upper
assert A == Q*R
def test_QR_non_square():
A = Matrix([[9, 0, 26], [12, 0, -7], [0, 4, 4], [0, -3, -3]])
Q, R = A.QRdecomposition()
assert Q.T * Q == eye(Q.cols)
assert R.is_upper
assert A == Q*R
A = Matrix([[1, -1, 4], [1, 4, -2], [1, 4, 2], [1, -1, 0]])
Q, R = A.QRdecomposition()
assert Q.T * Q == eye(Q.cols)
assert R.is_upper
assert A == Q*R
def test_nullspace():
# first test reduced row-ech form
R = Rational
M = Matrix([[5, 7, 2, 1],
[1, 6, 2, -1]])
out, tmp = M.rref()
assert out == Matrix([[1, 0, -R(2)/23, R(13)/23],
[0, 1, R(8)/23, R(-6)/23]])
M = Matrix([[-5, -1, 4, -3, -1],
[ 1, -1, -1, 1, 0],
[-1, 0, 0, 0, 0],
[ 4, 1, -4, 3, 1],
[-2, 0, 2, -2, -1]])
assert M*M.nullspace()[0] == Matrix(5, 1, [0]*5)
M = Matrix([[ 1, 3, 0, 2, 6, 3, 1],
[-2, -6, 0, -2, -8, 3, 1],
[ 3, 9, 0, 0, 6, 6, 2],
[-1, -3, 0, 1, 0, 9, 3]])
out, tmp = M.rref()
assert out == Matrix([[1, 3, 0, 0, 2, 0, 0],
[0, 0, 0, 1, 2, 0, 0],
[0, 0, 0, 0, 0, 1, R(1)/3],
[0, 0, 0, 0, 0, 0, 0]])
# now check the vectors
basis = M.nullspace()
assert basis[0] == Matrix([-3, 1, 0, 0, 0, 0, 0])
assert basis[1] == Matrix([0, 0, 1, 0, 0, 0, 0])
assert basis[2] == Matrix([-2, 0, 0, -2, 1, 0, 0])
assert basis[3] == Matrix([0, 0, 0, 0, 0, R(-1)/3, 1])
# issue 4797; just see that we can do it when rows > cols
M = Matrix([[1, 2], [2, 4], [3, 6]])
assert M.nullspace()
def test_columnspace():
M = Matrix([[ 1, 2, 0, 2, 5],
[-2, -5, 1, -1, -8],
[ 0, -3, 3, 4, 1],
[ 3, 6, 0, -7, 2]])
# now check the vectors
basis = M.columnspace()
assert basis[0] == Matrix([1, -2, 0, 3])
assert basis[1] == Matrix([2, -5, -3, 6])
assert basis[2] == Matrix([2, -1, 4, -7])
#check by columnspace definition
a, b, c, d, e = symbols('a b c d e')
X = Matrix([a, b, c, d, e])
for i in range(len(basis)):
eq=M*X-basis[i]
assert len(solve(eq, X)) != 0
#check if rank-nullity theorem holds
assert M.rank() == len(basis)
assert len(M.nullspace()) + len(M.columnspace()) == M.cols
def test_wronskian():
assert wronskian([cos(x), sin(x)], x) == cos(x)**2 + sin(x)**2
assert wronskian([exp(x), exp(2*x)], x) == exp(3*x)
assert wronskian([exp(x), x], x) == exp(x) - x*exp(x)
assert wronskian([1, x, x**2], x) == 2
w1 = -6*exp(x)*sin(x)*x + 6*cos(x)*exp(x)*x**2 - 6*exp(x)*cos(x)*x - \
exp(x)*cos(x)*x**3 + exp(x)*sin(x)*x**3
assert wronskian([exp(x), cos(x), x**3], x).expand() == w1
assert wronskian([exp(x), cos(x), x**3], x, method='berkowitz').expand() \
== w1
w2 = -x**3*cos(x)**2 - x**3*sin(x)**2 - 6*x*cos(x)**2 - 6*x*sin(x)**2
assert wronskian([sin(x), cos(x), x**3], x).expand() == w2
assert wronskian([sin(x), cos(x), x**3], x, method='berkowitz').expand() \
== w2
assert wronskian([], x) == 1
def test_eigen():
R = Rational
assert eye(3).charpoly(x) == Poly((x - 1)**3, x)
assert eye(3).charpoly(y) == Poly((y - 1)**3, y)
M = Matrix([[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
assert M.eigenvals(multiple=False) == {S.One: 3}
assert M.eigenvals(multiple=True) == [1, 1, 1]
assert M.eigenvects() == (
[(1, 3, [Matrix([1, 0, 0]),
Matrix([0, 1, 0]),
Matrix([0, 0, 1])])])
assert M.left_eigenvects() == (
[(1, 3, [Matrix([[1, 0, 0]]),
Matrix([[0, 1, 0]]),
Matrix([[0, 0, 1]])])])
M = Matrix([[0, 1, 1],
[1, 0, 0],
[1, 1, 1]])
assert M.eigenvals() == {2*S.One: 1, -S.One: 1, S.Zero: 1}
assert M.eigenvects() == (
[
(-1, 1, [Matrix([-1, 1, 0])]),
( 0, 1, [Matrix([0, -1, 1])]),
( 2, 1, [Matrix([R(2, 3), R(1, 3), 1])])
])
assert M.left_eigenvects() == (
[
(-1, 1, [Matrix([[-2, 1, 1]])]),
(0, 1, [Matrix([[-1, -1, 1]])]),
(2, 1, [Matrix([[1, 1, 1]])])
])
a = Symbol('a')
M = Matrix([[a, 0],
[0, 1]])
assert M.eigenvals() == {a: 1, S.One: 1}
M = Matrix([[1, -1],
[1, 3]])
assert M.eigenvects() == ([(2, 2, [Matrix(2, 1, [-1, 1])])])
assert M.left_eigenvects() == ([(2, 2, [Matrix([[1, 1]])])])
M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
a = R(15, 2)
b = 3*33**R(1, 2)
c = R(13, 2)
d = (R(33, 8) + 3*b/8)
e = (R(33, 8) - 3*b/8)
def NS(e, n):
return str(N(e, n))
r = [
(a - b/2, 1, [Matrix([(12 + 24/(c - b/2))/((c - b/2)*e) + 3/(c - b/2),
(6 + 12/(c - b/2))/e, 1])]),
( 0, 1, [Matrix([1, -2, 1])]),
(a + b/2, 1, [Matrix([(12 + 24/(c + b/2))/((c + b/2)*d) + 3/(c + b/2),
(6 + 12/(c + b/2))/d, 1])]),
]
r1 = [(NS(r[i][0], 2), NS(r[i][1], 2),
[NS(j, 2) for j in r[i][2][0]]) for i in range(len(r))]
r = M.eigenvects()
r2 = [(NS(r[i][0], 2), NS(r[i][1], 2),
[NS(j, 2) for j in r[i][2][0]]) for i in range(len(r))]
assert sorted(r1) == sorted(r2)
eps = Symbol('eps', real=True)
M = Matrix([[abs(eps), I*eps ],
[-I*eps, abs(eps) ]])
assert M.eigenvects() == (
[
( 0, 1, [Matrix([[-I*eps/abs(eps)], [1]])]),
( 2*abs(eps), 1, [ Matrix([[I*eps/abs(eps)], [1]]) ] ),
])
assert M.left_eigenvects() == (
[
(0, 1, [Matrix([[I*eps/Abs(eps), 1]])]),
(2*Abs(eps), 1, [Matrix([[-I*eps/Abs(eps), 1]])])
])
M = Matrix(3, 3, [1, 2, 0, 0, 3, 0, 2, -4, 2])
M._eigenvects = M.eigenvects(simplify=False)
assert max(i.q for i in M._eigenvects[0][2][0]) > 1
M._eigenvects = M.eigenvects(simplify=True)
assert max(i.q for i in M._eigenvects[0][2][0]) == 1
M = Matrix([[S(1)/4, 1], [1, 1]])
assert M.eigenvects(simplify=True) == [
(S(5)/8 + sqrt(73)/8, 1, [Matrix([[-S(3)/8 + sqrt(73)/8], [1]])]),
(-sqrt(73)/8 + S(5)/8, 1, [Matrix([[-sqrt(73)/8 - S(3)/8], [1]])])]
assert M.eigenvects(simplify=False) ==[(S(5)/8 + sqrt(73)/8, 1, [Matrix([
[-1/(-sqrt(73)/8 - S(3)/8)],
[ 1]])]), (-sqrt(73)/8 + S(5)/8, 1, [Matrix([
[-1/(-S(3)/8 + sqrt(73)/8)],
[ 1]])])]
m = Matrix([[1, .6, .6], [.6, .9, .9], [.9, .6, .6]])
evals = {-sqrt(385)/20 + S(5)/4: 1, sqrt(385)/20 + S(5)/4: 1, S.Zero: 1}
assert m.eigenvals() == evals
nevals = list(sorted(m.eigenvals(rational=False).keys()))
sevals = list(sorted(evals.keys()))
assert all(abs(nevals[i] - sevals[i]) < 1e-9 for i in range(len(nevals)))
# issue 10719
assert Matrix([]).eigenvals() == {}
assert Matrix([]).eigenvects() == []
# issue 15119
raises(NonSquareMatrixError, lambda : Matrix([[1, 2], [0, 4], [0, 0]]).eigenvals())
raises(NonSquareMatrixError, lambda : Matrix([[1, 0], [3, 4], [5, 6]]).eigenvals())
raises(NonSquareMatrixError, lambda : Matrix([[1, 2, 3], [0, 5, 6]]).eigenvals())
raises(NonSquareMatrixError, lambda : Matrix([[1, 0, 0], [4, 5, 0]]).eigenvals())
raises(NonSquareMatrixError, lambda : Matrix([[1, 2, 3], [0, 5, 6]]).eigenvals(error_when_incomplete = False))
raises(NonSquareMatrixError, lambda : Matrix([[1, 0, 0], [4, 5, 0]]).eigenvals(error_when_incomplete = False))
# issue 15125
from sympy.core.function import count_ops
q = Symbol("q", positive = True)
m = Matrix([[-2, exp(-q), 1], [exp(q), -2, 1], [1, 1, -2]])
assert count_ops(m.eigenvals(simplify=False)) > count_ops(m.eigenvals(simplify=True))
assert count_ops(m.eigenvals(simplify=lambda x: x)) > count_ops(m.eigenvals(simplify=True))
assert isinstance(m.eigenvals(simplify=True, multiple=False), dict)
assert isinstance(m.eigenvals(simplify=True, multiple=True), list)
assert isinstance(m.eigenvals(simplify=lambda x: x, multiple=False), dict)
assert isinstance(m.eigenvals(simplify=lambda x: x, multiple=True), list)
def test_subs():
assert Matrix([[1, x], [x, 4]]).subs(x, 5) == Matrix([[1, 5], [5, 4]])
assert Matrix([[x, 2], [x + y, 4]]).subs([[x, -1], [y, -2]]) == \
Matrix([[-1, 2], [-3, 4]])
assert Matrix([[x, 2], [x + y, 4]]).subs([(x, -1), (y, -2)]) == \
Matrix([[-1, 2], [-3, 4]])
assert Matrix([[x, 2], [x + y, 4]]).subs({x: -1, y: -2}) == \
Matrix([[-1, 2], [-3, 4]])
assert Matrix([x*y]).subs({x: y - 1, y: x - 1}, simultaneous=True) == \
Matrix([(x - 1)*(y - 1)])
for cls in classes:
assert Matrix([[2, 0], [0, 2]]) == cls.eye(2).subs(1, 2)
def test_xreplace():
assert Matrix([[1, x], [x, 4]]).xreplace({x: 5}) == \
Matrix([[1, 5], [5, 4]])
assert Matrix([[x, 2], [x + y, 4]]).xreplace({x: -1, y: -2}) == \
Matrix([[-1, 2], [-3, 4]])
for cls in classes:
assert Matrix([[2, 0], [0, 2]]) == cls.eye(2).xreplace({1: 2})
def test_simplify():
n = Symbol('n')
f = Function('f')
M = Matrix([[ 1/x + 1/y, (x + x*y) / x ],
[ (f(x) + y*f(x))/f(x), 2 * (1/n - cos(n * pi)/n) / pi ]])
M.simplify()
assert M == Matrix([[ (x + y)/(x * y), 1 + y ],
[ 1 + y, 2*((1 - 1*cos(pi*n))/(pi*n)) ]])
eq = (1 + x)**2
M = Matrix([[eq]])
M.simplify()
assert M == Matrix([[eq]])
M.simplify(ratio=oo) == M
assert M == Matrix([[eq.simplify(ratio=oo)]])
def test_transpose():
M = Matrix([[1, 2, 3, 4, 5, 6, 7, 8, 9, 0],
[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]])
assert M.T == Matrix( [ [1, 1],
[2, 2],
[3, 3],
[4, 4],
[5, 5],
[6, 6],
[7, 7],
[8, 8],
[9, 9],
[0, 0] ])
assert M.T.T == M
assert M.T == M.transpose()
def test_conjugate():
M = Matrix([[0, I, 5],
[1, 2, 0]])
assert M.T == Matrix([[0, 1],
[I, 2],
[5, 0]])
assert M.C == Matrix([[0, -I, 5],
[1, 2, 0]])
assert M.C == M.conjugate()
assert M.H == M.T.C
assert M.H == Matrix([[ 0, 1],
[-I, 2],
[ 5, 0]])
def test_conj_dirac():
raises(AttributeError, lambda: eye(3).D)
M = Matrix([[1, I, I, I],
[0, 1, I, I],
[0, 0, 1, I],
[0, 0, 0, 1]])
assert M.D == Matrix([[ 1, 0, 0, 0],
[-I, 1, 0, 0],
[-I, -I, -1, 0],
[-I, -I, I, -1]])
def test_trace():
M = Matrix([[1, 0, 0],
[0, 5, 0],
[0, 0, 8]])
assert M.trace() == 14
def test_shape():
M = Matrix([[x, 0, 0],
[0, y, 0]])
assert M.shape == (2, 3)
def test_col_row_op():
M = Matrix([[x, 0, 0],
[0, y, 0]])
M.row_op(1, lambda r, j: r + j + 1)
assert M == Matrix([[x, 0, 0],
[1, y + 2, 3]])
M.col_op(0, lambda c, j: c + y**j)
assert M == Matrix([[x + 1, 0, 0],
[1 + y, y + 2, 3]])
# neither row nor slice give copies that allow the original matrix to
# be changed
assert M.row(0) == Matrix([[x + 1, 0, 0]])
r1 = M.row(0)
r1[0] = 42
assert M[0, 0] == x + 1
r1 = M[0, :-1] # also testing negative slice
r1[0] = 42
assert M[0, 0] == x + 1
c1 = M.col(0)
assert c1 == Matrix([x + 1, 1 + y])
c1[0] = 0
assert M[0, 0] == x + 1
c1 = M[:, 0]
c1[0] = 42
assert M[0, 0] == x + 1
def test_zip_row_op():
for cls in classes[:2]: # XXX: immutable matrices don't support row ops
M = cls.eye(3)
M.zip_row_op(1, 0, lambda v, u: v + 2*u)
assert M == cls([[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
M = cls.eye(3)*2
M[0, 1] = -1
M.zip_row_op(1, 0, lambda v, u: v + 2*u); M
assert M == cls([[2, -1, 0],
[4, 0, 0],
[0, 0, 2]])
def test_issue_3950():
m = Matrix([1, 2, 3])
a = Matrix([1, 2, 3])
b = Matrix([2, 2, 3])
assert not (m in [])
assert not (m in [1])
assert m != 1
assert m == a
assert m != b
def test_issue_3981():
class Index1(object):
def __index__(self):
return 1
class Index2(object):
def __index__(self):
return 2
index1 = Index1()
index2 = Index2()
m = Matrix([1, 2, 3])
assert m[index2] == 3
m[index2] = 5
assert m[2] == 5
m = Matrix([[1, 2, 3], [4, 5, 6]])
assert m[index1, index2] == 6
assert m[1, index2] == 6
assert m[index1, 2] == 6
m[index1, index2] = 4
assert m[1, 2] == 4
m[1, index2] = 6
assert m[1, 2] == 6
m[index1, 2] = 8
assert m[1, 2] == 8
def test_evalf():
a = Matrix([sqrt(5), 6])
assert all(a.evalf()[i] == a[i].evalf() for i in range(2))
assert all(a.evalf(2)[i] == a[i].evalf(2) for i in range(2))
assert all(a.n(2)[i] == a[i].n(2) for i in range(2))
def test_is_symbolic():
a = Matrix([[x, x], [x, x]])
assert a.is_symbolic() is True
a = Matrix([[1, 2, 3, 4], [5, 6, 7, 8]])
assert a.is_symbolic() is False
a = Matrix([[1, 2, 3, 4], [5, 6, x, 8]])
assert a.is_symbolic() is True
a = Matrix([[1, x, 3]])
assert a.is_symbolic() is True
a = Matrix([[1, 2, 3]])
assert a.is_symbolic() is False
a = Matrix([[1], [x], [3]])
assert a.is_symbolic() is True
a = Matrix([[1], [2], [3]])
assert a.is_symbolic() is False
def test_is_upper():
a = Matrix([[1, 2, 3]])
assert a.is_upper is True
a = Matrix([[1], [2], [3]])
assert a.is_upper is False
a = zeros(4, 2)
assert a.is_upper is True
def test_is_lower():
a = Matrix([[1, 2, 3]])
assert a.is_lower is False
a = Matrix([[1], [2], [3]])
assert a.is_lower is True
def test_is_nilpotent():
a = Matrix(4, 4, [0, 2, 1, 6, 0, 0, 1, 2, 0, 0, 0, 3, 0, 0, 0, 0])
assert a.is_nilpotent()
a = Matrix([[1, 0], [0, 1]])
assert not a.is_nilpotent()
a = Matrix([])
assert a.is_nilpotent()
def test_zeros_ones_fill():
n, m = 3, 5
a = zeros(n, m)
a.fill( 5 )
b = 5 * ones(n, m)
assert a == b
assert a.rows == b.rows == 3
assert a.cols == b.cols == 5
assert a.shape == b.shape == (3, 5)
assert zeros(2) == zeros(2, 2)
assert ones(2) == ones(2, 2)
assert zeros(2, 3) == Matrix(2, 3, [0]*6)
assert ones(2, 3) == Matrix(2, 3, [1]*6)
def test_empty_zeros():
a = zeros(0)
assert a == Matrix()
a = zeros(0, 2)
assert a.rows == 0
assert a.cols == 2
a = zeros(2, 0)
assert a.rows == 2
assert a.cols == 0
def test_issue_3749():
a = Matrix([[x**2, x*y], [x*sin(y), x*cos(y)]])
assert a.diff(x) == Matrix([[2*x, y], [sin(y), cos(y)]])
assert Matrix([
[x, -x, x**2],
[exp(x), 1/x - exp(-x), x + 1/x]]).limit(x, oo) == \
Matrix([[oo, -oo, oo], [oo, 0, oo]])
assert Matrix([
[(exp(x) - 1)/x, 2*x + y*x, x**x ],
[1/x, abs(x), abs(sin(x + 1))]]).limit(x, 0) == \
Matrix([[1, 0, 1], [oo, 0, sin(1)]])
assert a.integrate(x) == Matrix([
[Rational(1, 3)*x**3, y*x**2/2],
[x**2*sin(y)/2, x**2*cos(y)/2]])
def test_inv_iszerofunc():
A = eye(4)
A.col_swap(0, 1)
for method in "GE", "LU":
assert A.inv(method=method, iszerofunc=lambda x: x == 0) == \
A.inv(method="ADJ")
def test_jacobian_metrics():
rho, phi = symbols("rho,phi")
X = Matrix([rho*cos(phi), rho*sin(phi)])
Y = Matrix([rho, phi])
J = X.jacobian(Y)
assert J == X.jacobian(Y.T)
assert J == (X.T).jacobian(Y)
assert J == (X.T).jacobian(Y.T)
g = J.T*eye(J.shape[0])*J
g = g.applyfunc(trigsimp)
assert g == Matrix([[1, 0], [0, rho**2]])
def test_jacobian2():
rho, phi = symbols("rho,phi")
X = Matrix([rho*cos(phi), rho*sin(phi), rho**2])
Y = Matrix([rho, phi])
J = Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)],
[ 2*rho, 0],
])
assert X.jacobian(Y) == J
def test_issue_4564():
X = Matrix([exp(x + y + z), exp(x + y + z), exp(x + y + z)])
Y = Matrix([x, y, z])
for i in range(1, 3):
for j in range(1, 3):
X_slice = X[:i, :]
Y_slice = Y[:j, :]
J = X_slice.jacobian(Y_slice)
assert J.rows == i
assert J.cols == j
for k in range(j):
assert J[:, k] == X_slice
def test_nonvectorJacobian():
X = Matrix([[exp(x + y + z), exp(x + y + z)],
[exp(x + y + z), exp(x + y + z)]])
raises(TypeError, lambda: X.jacobian(Matrix([x, y, z])))
X = X[0, :]
Y = Matrix([[x, y], [x, z]])
raises(TypeError, lambda: X.jacobian(Y))
raises(TypeError, lambda: X.jacobian(Matrix([ [x, y], [x, z] ])))
def test_vec():
m = Matrix([[1, 3], [2, 4]])
m_vec = m.vec()
assert m_vec.cols == 1
for i in range(4):
assert m_vec[i] == i + 1
def test_vech():
m = Matrix([[1, 2], [2, 3]])
m_vech = m.vech()
assert m_vech.cols == 1
for i in range(3):
assert m_vech[i] == i + 1
m_vech = m.vech(diagonal=False)
assert m_vech[0] == 2
m = Matrix([[1, x*(x + y)], [y*x + x**2, 1]])
m_vech = m.vech(diagonal=False)
assert m_vech[0] == x*(x + y)
m = Matrix([[1, x*(x + y)], [y*x, 1]])
m_vech = m.vech(diagonal=False, check_symmetry=False)
assert m_vech[0] == y*x
def test_vech_errors():
m = Matrix([[1, 3]])
raises(ShapeError, lambda: m.vech())
m = Matrix([[1, 3], [2, 4]])
raises(ValueError, lambda: m.vech())
raises(ShapeError, lambda: Matrix([ [1, 3] ]).vech())
raises(ValueError, lambda: Matrix([ [1, 3], [2, 4] ]).vech())
def test_diag():
a = Matrix([[1, 2], [2, 3]])
b = Matrix([[3, x], [y, 3]])
c = Matrix([[3, x, 3], [y, 3, z], [x, y, z]])
assert diag(a, b, b) == Matrix([
[1, 2, 0, 0, 0, 0],
[2, 3, 0, 0, 0, 0],
[0, 0, 3, x, 0, 0],
[0, 0, y, 3, 0, 0],
[0, 0, 0, 0, 3, x],
[0, 0, 0, 0, y, 3],
])
assert diag(a, b, c) == Matrix([
[1, 2, 0, 0, 0, 0, 0],
[2, 3, 0, 0, 0, 0, 0],
[0, 0, 3, x, 0, 0, 0],
[0, 0, y, 3, 0, 0, 0],
[0, 0, 0, 0, 3, x, 3],
[0, 0, 0, 0, y, 3, z],
[0, 0, 0, 0, x, y, z],
])
assert diag(a, c, b) == Matrix([
[1, 2, 0, 0, 0, 0, 0],
[2, 3, 0, 0, 0, 0, 0],
[0, 0, 3, x, 3, 0, 0],
[0, 0, y, 3, z, 0, 0],
[0, 0, x, y, z, 0, 0],
[0, 0, 0, 0, 0, 3, x],
[0, 0, 0, 0, 0, y, 3],
])
a = Matrix([x, y, z])
b = Matrix([[1, 2], [3, 4]])
c = Matrix([[5, 6]])
assert diag(a, 7, b, c) == Matrix([
[x, 0, 0, 0, 0, 0],
[y, 0, 0, 0, 0, 0],
[z, 0, 0, 0, 0, 0],
[0, 7, 0, 0, 0, 0],
[0, 0, 1, 2, 0, 0],
[0, 0, 3, 4, 0, 0],
[0, 0, 0, 0, 5, 6],
])
assert diag(1, [2, 3], [[4, 5]]) == Matrix([
[1, 0, 0, 0],
[0, 2, 0, 0],
[0, 3, 0, 0],
[0, 0, 4, 5]])
def test_get_diag_blocks1():
a = Matrix([[1, 2], [2, 3]])
b = Matrix([[3, x], [y, 3]])
c = Matrix([[3, x, 3], [y, 3, z], [x, y, z]])
assert a.get_diag_blocks() == [a]
assert b.get_diag_blocks() == [b]
assert c.get_diag_blocks() == [c]
def test_get_diag_blocks2():
a = Matrix([[1, 2], [2, 3]])
b = Matrix([[3, x], [y, 3]])
c = Matrix([[3, x, 3], [y, 3, z], [x, y, z]])
assert diag(a, b, b).get_diag_blocks() == [a, b, b]
assert diag(a, b, c).get_diag_blocks() == [a, b, c]
assert diag(a, c, b).get_diag_blocks() == [a, c, b]
assert diag(c, c, b).get_diag_blocks() == [c, c, b]
def test_inv_block():
a = Matrix([[1, 2], [2, 3]])
b = Matrix([[3, x], [y, 3]])
c = Matrix([[3, x, 3], [y, 3, z], [x, y, z]])
A = diag(a, b, b)
assert A.inv(try_block_diag=True) == diag(a.inv(), b.inv(), b.inv())
A = diag(a, b, c)
assert A.inv(try_block_diag=True) == diag(a.inv(), b.inv(), c.inv())
A = diag(a, c, b)
assert A.inv(try_block_diag=True) == diag(a.inv(), c.inv(), b.inv())
A = diag(a, a, b, a, c, a)
assert A.inv(try_block_diag=True) == diag(
a.inv(), a.inv(), b.inv(), a.inv(), c.inv(), a.inv())
assert A.inv(try_block_diag=True, method="ADJ") == diag(
a.inv(method="ADJ"), a.inv(method="ADJ"), b.inv(method="ADJ"),
a.inv(method="ADJ"), c.inv(method="ADJ"), a.inv(method="ADJ"))
def test_creation_args():
"""
Check that matrix dimensions can be specified using any reasonable type
(see issue 4614).
"""
raises(ValueError, lambda: zeros(3, -1))
raises(TypeError, lambda: zeros(1, 2, 3, 4))
assert zeros(long(3)) == zeros(3)
assert zeros(Integer(3)) == zeros(3)
assert zeros(3.) == zeros(3)
assert eye(long(3)) == eye(3)
assert eye(Integer(3)) == eye(3)
assert eye(3.) == eye(3)
assert ones(long(3), Integer(4)) == ones(3, 4)
raises(TypeError, lambda: Matrix(5))
raises(TypeError, lambda: Matrix(1, 2))
def test_diagonal_symmetrical():
m = Matrix(2, 2, [0, 1, 1, 0])
assert not m.is_diagonal()
assert m.is_symmetric()
assert m.is_symmetric(simplify=False)
m = Matrix(2, 2, [1, 0, 0, 1])
assert m.is_diagonal()
m = diag(1, 2, 3)
assert m.is_diagonal()
assert m.is_symmetric()
m = Matrix(3, 3, [1, 0, 0, 0, 2, 0, 0, 0, 3])
assert m == diag(1, 2, 3)
m = Matrix(2, 3, zeros(2, 3))
assert not m.is_symmetric()
assert m.is_diagonal()
m = Matrix(((5, 0), (0, 6), (0, 0)))
assert m.is_diagonal()
m = Matrix(((5, 0, 0), (0, 6, 0)))
assert m.is_diagonal()
m = Matrix(3, 3, [1, x**2 + 2*x + 1, y, (x + 1)**2, 2, 0, y, 0, 3])
assert m.is_symmetric()
assert not m.is_symmetric(simplify=False)
assert m.expand().is_symmetric(simplify=False)
def test_diagonalization():
m = Matrix(3, 2, [-3, 1, -3, 20, 3, 10])
assert not m.is_diagonalizable()
assert not m.is_symmetric()
raises(NonSquareMatrixError, lambda: m.diagonalize())
# diagonalizable
m = diag(1, 2, 3)
(P, D) = m.diagonalize()
assert P == eye(3)
assert D == m
m = Matrix(2, 2, [0, 1, 1, 0])
assert m.is_symmetric()
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
m = Matrix(2, 2, [1, 0, 0, 3])
assert m.is_symmetric()
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
assert P == eye(2)
assert D == m
m = Matrix(2, 2, [1, 1, 0, 0])
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
m = Matrix(3, 3, [1, 2, 0, 0, 3, 0, 2, -4, 2])
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
for i in P:
assert i.as_numer_denom()[1] == 1
m = Matrix(2, 2, [1, 0, 0, 0])
assert m.is_diagonal()
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
assert P == Matrix([[0, 1], [1, 0]])
# diagonalizable, complex only
m = Matrix(2, 2, [0, 1, -1, 0])
assert not m.is_diagonalizable(True)
raises(MatrixError, lambda: m.diagonalize(True))
assert m.is_diagonalizable()
(P, D) = m.diagonalize()
assert P.inv() * m * P == D
# not diagonalizable
m = Matrix(2, 2, [0, 1, 0, 0])
assert not m.is_diagonalizable()
raises(MatrixError, lambda: m.diagonalize())
m = Matrix(3, 3, [-3, 1, -3, 20, 3, 10, 2, -2, 4])
assert not m.is_diagonalizable()
raises(MatrixError, lambda: m.diagonalize())
# symbolic
a, b, c, d = symbols('a b c d')
m = Matrix(2, 2, [a, c, c, b])
assert m.is_symmetric()
assert m.is_diagonalizable()
@XFAIL
def test_eigen_vects():
m = Matrix(2, 2, [1, 0, 0, I])
raises(NotImplementedError, lambda: m.is_diagonalizable(True))
# !!! bug because of eigenvects() or roots(x**2 + (-1 - I)*x + I, x)
# see issue 5292
assert not m.is_diagonalizable(True)
raises(MatrixError, lambda: m.diagonalize(True))
(P, D) = m.diagonalize(True)
def test_jordan_form():
m = Matrix(3, 2, [-3, 1, -3, 20, 3, 10])
raises(NonSquareMatrixError, lambda: m.jordan_form())
# diagonalizable
m = Matrix(3, 3, [7, -12, 6, 10, -19, 10, 12, -24, 13])
Jmust = Matrix(3, 3, [-1, 0, 0, 0, 1, 0, 0, 0, 1])
P, J = m.jordan_form()
assert Jmust == J
assert Jmust == m.diagonalize()[1]
# m = Matrix(3, 3, [0, 6, 3, 1, 3, 1, -2, 2, 1])
# m.jordan_form() # very long
# m.jordan_form() #
# diagonalizable, complex only
# Jordan cells
# complexity: one of eigenvalues is zero
m = Matrix(3, 3, [0, 1, 0, -4, 4, 0, -2, 1, 2])
# The blocks are ordered according to the value of their eigenvalues,
# in order to make the matrix compatible with .diagonalize()
Jmust = Matrix(3, 3, [2, 1, 0, 0, 2, 0, 0, 0, 2])
P, J = m.jordan_form()
assert Jmust == J
# complexity: all of eigenvalues are equal
m = Matrix(3, 3, [2, 6, -15, 1, 1, -5, 1, 2, -6])
# Jmust = Matrix(3, 3, [-1, 0, 0, 0, -1, 1, 0, 0, -1])
# same here see 1456ff
Jmust = Matrix(3, 3, [-1, 1, 0, 0, -1, 0, 0, 0, -1])
P, J = m.jordan_form()
assert Jmust == J
# complexity: two of eigenvalues are zero
m = Matrix(3, 3, [4, -5, 2, 5, -7, 3, 6, -9, 4])
Jmust = Matrix(3, 3, [0, 1, 0, 0, 0, 0, 0, 0, 1])
P, J = m.jordan_form()
assert Jmust == J
m = Matrix(4, 4, [6, 5, -2, -3, -3, -1, 3, 3, 2, 1, -2, -3, -1, 1, 5, 5])
Jmust = Matrix(4, 4, [2, 1, 0, 0,
0, 2, 0, 0,
0, 0, 2, 1,
0, 0, 0, 2]
)
P, J = m.jordan_form()
assert Jmust == J
m = Matrix(4, 4, [6, 2, -8, -6, -3, 2, 9, 6, 2, -2, -8, -6, -1, 0, 3, 4])
# Jmust = Matrix(4, 4, [2, 0, 0, 0, 0, 2, 1, 0, 0, 0, 2, 0, 0, 0, 0, -2])
# same here see 1456ff
Jmust = Matrix(4, 4, [-2, 0, 0, 0,
0, 2, 1, 0,
0, 0, 2, 0,
0, 0, 0, 2])
P, J = m.jordan_form()
assert Jmust == J
m = Matrix(4, 4, [5, 4, 2, 1, 0, 1, -1, -1, -1, -1, 3, 0, 1, 1, -1, 2])
assert not m.is_diagonalizable()
Jmust = Matrix(4, 4, [1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 4, 1, 0, 0, 0, 4])
P, J = m.jordan_form()
assert Jmust == J
# checking for maximum precision to remain unchanged
m = Matrix([[Float('1.0', precision=110), Float('2.0', precision=110)],
[Float('3.14159265358979323846264338327', precision=110), Float('4.0', precision=110)]])
P, J = m.jordan_form()
for term in J._mat:
if isinstance(term, Float):
assert term._prec == 110
def test_jordan_form_complex_issue_9274():
A = Matrix([[ 2, 4, 1, 0],
[-4, 2, 0, 1],
[ 0, 0, 2, 4],
[ 0, 0, -4, 2]])
p = 2 - 4*I;
q = 2 + 4*I;
Jmust1 = Matrix([[p, 1, 0, 0],
[0, p, 0, 0],
[0, 0, q, 1],
[0, 0, 0, q]])
Jmust2 = Matrix([[q, 1, 0, 0],
[0, q, 0, 0],
[0, 0, p, 1],
[0, 0, 0, p]])
P, J = A.jordan_form()
assert J == Jmust1 or J == Jmust2
assert simplify(P*J*P.inv()) == A
def test_issue_10220():
# two non-orthogonal Jordan blocks with eigenvalue 1
M = Matrix([[1, 0, 0, 1],
[0, 1, 1, 0],
[0, 0, 1, 1],
[0, 0, 0, 1]])
P, J = M.jordan_form()
assert P == Matrix([[0, 1, 0, 1],
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0]])
assert J == Matrix([
[1, 1, 0, 0],
[0, 1, 1, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]])
def test_Matrix_berkowitz_charpoly():
UA, K_i, K_w = symbols('UA K_i K_w')
A = Matrix([[-K_i - UA + K_i**2/(K_i + K_w), K_i*K_w/(K_i + K_w)],
[ K_i*K_w/(K_i + K_w), -K_w + K_w**2/(K_i + K_w)]])
charpoly = A.charpoly(x)
assert charpoly == \
Poly(x**2 + (K_i*UA + K_w*UA + 2*K_i*K_w)/(K_i + K_w)*x +
K_i*K_w*UA/(K_i + K_w), x, domain='ZZ(K_i,K_w,UA)')
assert type(charpoly) is PurePoly
A = Matrix([[1, 3], [2, 0]])
assert A.charpoly() == A.charpoly(x) == PurePoly(x**2 - x - 6)
A = Matrix([[1, 2], [x, 0]])
p = A.charpoly(x)
assert p.gen != x
assert p.as_expr().subs(p.gen, x) == x**2 - 3*x
def test_exp():
m = Matrix([[3, 4], [0, -2]])
m_exp = Matrix([[exp(3), -4*exp(-2)/5 + 4*exp(3)/5], [0, exp(-2)]])
assert m.exp() == m_exp
assert exp(m) == m_exp
m = Matrix([[1, 0], [0, 1]])
assert m.exp() == Matrix([[E, 0], [0, E]])
assert exp(m) == Matrix([[E, 0], [0, E]])
m = Matrix([[1, -1], [1, 1]])
assert m.exp() == Matrix([[E*cos(1), -E*sin(1)], [E*sin(1), E*cos(1)]])
def test_has():
A = Matrix(((x, y), (2, 3)))
assert A.has(x)
assert not A.has(z)
assert A.has(Symbol)
A = A.subs(x, 2)
assert not A.has(x)
def test_LUdecomposition_Simple_iszerofunc():
# Test if callable passed to matrices.LUdecomposition_Simple() as iszerofunc keyword argument is used inside
# matrices.LUdecomposition_Simple()
magic_string = "I got passed in!"
def goofyiszero(value):
raise ValueError(magic_string)
try:
lu, p = Matrix([[1, 0], [0, 1]]).LUdecomposition_Simple(iszerofunc=goofyiszero)
except ValueError as err:
assert magic_string == err.args[0]
return
assert False
def test_LUdecomposition_iszerofunc():
# Test if callable passed to matrices.LUdecomposition() as iszerofunc keyword argument is used inside
# matrices.LUdecomposition_Simple()
magic_string = "I got passed in!"
def goofyiszero(value):
raise ValueError(magic_string)
try:
l, u, p = Matrix([[1, 0], [0, 1]]).LUdecomposition(iszerofunc=goofyiszero)
except ValueError as err:
assert magic_string == err.args[0]
return
assert False
def test_find_reasonable_pivot_naive_finds_guaranteed_nonzero1():
# Test if matrices._find_reasonable_pivot_naive()
# finds a guaranteed non-zero pivot when the
# some of the candidate pivots are symbolic expressions.
# Keyword argument: simpfunc=None indicates that no simplifications
# should be performed during the search.
x = Symbol('x')
column = Matrix(3, 1, [x, cos(x)**2 + sin(x)**2, Rational(1, 2)])
pivot_offset, pivot_val, pivot_assumed_nonzero, simplified =\
_find_reasonable_pivot_naive(column)
assert pivot_val == Rational(1, 2)
def test_find_reasonable_pivot_naive_finds_guaranteed_nonzero2():
# Test if matrices._find_reasonable_pivot_naive()
# finds a guaranteed non-zero pivot when the
# some of the candidate pivots are symbolic expressions.
# Keyword argument: simpfunc=_simplify indicates that the search
# should attempt to simplify candidate pivots.
x = Symbol('x')
column = Matrix(3, 1,
[x,
cos(x)**2+sin(x)**2+x**2,
cos(x)**2+sin(x)**2])
pivot_offset, pivot_val, pivot_assumed_nonzero, simplified =\
_find_reasonable_pivot_naive(column, simpfunc=_simplify)
assert pivot_val == 1
def test_find_reasonable_pivot_naive_simplifies():
# Test if matrices._find_reasonable_pivot_naive()
# simplifies candidate pivots, and reports
# their offsets correctly.
x = Symbol('x')
column = Matrix(3, 1,
[x,
cos(x)**2+sin(x)**2+x,
cos(x)**2+sin(x)**2])
pivot_offset, pivot_val, pivot_assumed_nonzero, simplified =\
_find_reasonable_pivot_naive(column, simpfunc=_simplify)
assert len(simplified) == 2
assert simplified[0][0] == 1
assert simplified[0][1] == 1+x
assert simplified[1][0] == 2
assert simplified[1][1] == 1
def test_errors():
raises(ValueError, lambda: Matrix([[1, 2], [1]]))
raises(IndexError, lambda: Matrix([[1, 2]])[1.2, 5])
raises(IndexError, lambda: Matrix([[1, 2]])[1, 5.2])
raises(ValueError, lambda: randMatrix(3, c=4, symmetric=True))
raises(ValueError, lambda: Matrix([1, 2]).reshape(4, 6))
raises(ShapeError,
lambda: Matrix([[1, 2], [3, 4]]).copyin_matrix([1, 0], Matrix([1, 2])))
raises(TypeError, lambda: Matrix([[1, 2], [3, 4]]).copyin_list([0,
1], set([])))
raises(NonSquareMatrixError, lambda: Matrix([[1, 2, 3], [2, 3, 0]]).inv())
raises(ShapeError,
lambda: Matrix(1, 2, [1, 2]).row_join(Matrix([[1, 2], [3, 4]])))
raises(
ShapeError, lambda: Matrix([1, 2]).col_join(Matrix([[1, 2], [3, 4]])))
raises(ShapeError, lambda: Matrix([1]).row_insert(1, Matrix([[1,
2], [3, 4]])))
raises(ShapeError, lambda: Matrix([1]).col_insert(1, Matrix([[1,
2], [3, 4]])))
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).trace())
raises(TypeError, lambda: Matrix([1]).applyfunc(1))
raises(ShapeError, lambda: Matrix([1]).LUsolve(Matrix([[1, 2], [3, 4]])))
raises(MatrixError, lambda: Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]
]).QRdecomposition())
raises(MatrixError, lambda: Matrix(1, 2, [1, 2]).QRdecomposition())
raises(ValueError, lambda: Matrix([[1, 2], [3, 4]]).minor(4, 5))
raises(ValueError, lambda: Matrix([[1, 2], [3, 4]]).minor_submatrix(4, 5))
raises(TypeError, lambda: Matrix([1, 2, 3]).cross(1))
raises(TypeError, lambda: Matrix([1, 2, 3]).dot(1))
raises(ShapeError, lambda: Matrix([1, 2, 3]).dot(Matrix([1, 2])))
raises(ShapeError, lambda: Matrix([1, 2]).dot([]))
raises(TypeError, lambda: Matrix([1, 2]).dot('a'))
with warns_deprecated_sympy():
Matrix([[1, 2], [3, 4]]).dot(Matrix([[4, 3], [1, 2]]))
raises(ShapeError, lambda: Matrix([1, 2]).dot([1, 2, 3]))
raises(NonSquareMatrixError, lambda: Matrix([1, 2, 3]).exp())
raises(ShapeError, lambda: Matrix([[1, 2], [3, 4]]).normalized())
raises(ValueError, lambda: Matrix([1, 2]).inv(method='not a method'))
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).inverse_GE())
raises(ValueError, lambda: Matrix([[1, 2], [1, 2]]).inverse_GE())
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).inverse_ADJ())
raises(ValueError, lambda: Matrix([[1, 2], [1, 2]]).inverse_ADJ())
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).inverse_LU())
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).is_nilpotent())
raises(NonSquareMatrixError, lambda: Matrix([1, 2]).det())
raises(ValueError,
lambda: Matrix([[1, 2], [3, 4]]).det(method='Not a real method'))
raises(ValueError,
lambda: Matrix([[1, 2, 3, 4], [5, 6, 7, 8],
[9, 10, 11, 12], [13, 14, 15, 16]]).det(iszerofunc="Not function"))
raises(ValueError,
lambda: Matrix([[1, 2, 3, 4], [5, 6, 7, 8],
[9, 10, 11, 12], [13, 14, 15, 16]]).det(iszerofunc=False))
raises(ValueError,
lambda: hessian(Matrix([[1, 2], [3, 4]]), Matrix([[1, 2], [2, 1]])))
raises(ValueError, lambda: hessian(Matrix([[1, 2], [3, 4]]), []))
raises(ValueError, lambda: hessian(Symbol('x')**2, 'a'))
raises(IndexError, lambda: eye(3)[5, 2])
raises(IndexError, lambda: eye(3)[2, 5])
M = Matrix(((1, 2, 3, 4), (5, 6, 7, 8), (9, 10, 11, 12), (13, 14, 15, 16)))
raises(ValueError, lambda: M.det('method=LU_decomposition()'))
V = Matrix([[10, 10, 10]])
M = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(ValueError, lambda: M.row_insert(4.7, V))
M = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(ValueError, lambda: M.col_insert(-4.2, V))
def test_len():
assert len(Matrix()) == 0
assert len(Matrix([[1, 2]])) == len(Matrix([[1], [2]])) == 2
assert len(Matrix(0, 2, lambda i, j: 0)) == \
len(Matrix(2, 0, lambda i, j: 0)) == 0
assert len(Matrix([[0, 1, 2], [3, 4, 5]])) == 6
assert Matrix([1]) == Matrix([[1]])
assert not Matrix()
assert Matrix() == Matrix([])
def test_integrate():
A = Matrix(((1, 4, x), (y, 2, 4), (10, 5, x**2)))
assert A.integrate(x) == \
Matrix(((x, 4*x, x**2/2), (x*y, 2*x, 4*x), (10*x, 5*x, x**3/3)))
assert A.integrate(y) == \
Matrix(((y, 4*y, x*y), (y**2/2, 2*y, 4*y), (10*y, 5*y, y*x**2)))
def test_limit():
A = Matrix(((1, 4, sin(x)/x), (y, 2, 4), (10, 5, x**2 + 1)))
assert A.limit(x, 0) == Matrix(((1, 4, 1), (y, 2, 4), (10, 5, 1)))
def test_diff():
A = MutableDenseMatrix(((1, 4, x), (y, 2, 4), (10, 5, x**2 + 1)))
assert isinstance(A.diff(x), type(A))
assert A.diff(x) == MutableDenseMatrix(((0, 0, 1), (0, 0, 0), (0, 0, 2*x)))
assert A.diff(y) == MutableDenseMatrix(((0, 0, 0), (1, 0, 0), (0, 0, 0)))
assert diff(A, x) == MutableDenseMatrix(((0, 0, 1), (0, 0, 0), (0, 0, 2*x)))
assert diff(A, y) == MutableDenseMatrix(((0, 0, 0), (1, 0, 0), (0, 0, 0)))
A_imm = A.as_immutable()
assert isinstance(A_imm.diff(x), type(A_imm))
assert A_imm.diff(x) == ImmutableDenseMatrix(((0, 0, 1), (0, 0, 0), (0, 0, 2*x)))
assert A_imm.diff(y) == ImmutableDenseMatrix(((0, 0, 0), (1, 0, 0), (0, 0, 0)))
assert diff(A_imm, x) == ImmutableDenseMatrix(((0, 0, 1), (0, 0, 0), (0, 0, 2*x)))
assert diff(A_imm, y) == ImmutableDenseMatrix(((0, 0, 0), (1, 0, 0), (0, 0, 0)))
def test_diff_by_matrix():
# Derive matrix by matrix:
A = MutableDenseMatrix([[x, y], [z, t]])
assert A.diff(A) == Array([[[[1, 0], [0, 0]], [[0, 1], [0, 0]]], [[[0, 0], [1, 0]], [[0, 0], [0, 1]]]])
assert diff(A, A) == Array([[[[1, 0], [0, 0]], [[0, 1], [0, 0]]], [[[0, 0], [1, 0]], [[0, 0], [0, 1]]]])
A_imm = A.as_immutable()
assert A_imm.diff(A_imm) == Array([[[[1, 0], [0, 0]], [[0, 1], [0, 0]]], [[[0, 0], [1, 0]], [[0, 0], [0, 1]]]])
assert diff(A_imm, A_imm) == Array([[[[1, 0], [0, 0]], [[0, 1], [0, 0]]], [[[0, 0], [1, 0]], [[0, 0], [0, 1]]]])
# Derive a constant matrix:
assert A.diff(a) == MutableDenseMatrix([[0, 0], [0, 0]])
B = ImmutableDenseMatrix([a, b])
assert A.diff(B) == A.zeros(2)
# Test diff with tuples:
dB = B.diff([[a, b]])
assert dB.shape == (2, 2, 1)
assert dB == Array([[[1], [0]], [[0], [1]]])
f = Function("f")
fxyz = f(x, y, z)
assert fxyz.diff([[x, y, z]]) == Array([fxyz.diff(x), fxyz.diff(y), fxyz.diff(z)])
assert fxyz.diff(([x, y, z], 2)) == Array([
[fxyz.diff(x, 2), fxyz.diff(x, y), fxyz.diff(x, z)],
[fxyz.diff(x, y), fxyz.diff(y, 2), fxyz.diff(y, z)],
[fxyz.diff(x, z), fxyz.diff(z, y), fxyz.diff(z, 2)],
])
expr = sin(x)*exp(y)
assert expr.diff([[x, y]]) == Array([cos(x)*exp(y), sin(x)*exp(y)])
assert expr.diff(y, ((x, y),)) == Array([cos(x)*exp(y), sin(x)*exp(y)])
assert expr.diff(x, ((x, y),)) == Array([-sin(x)*exp(y), cos(x)*exp(y)])
assert expr.diff(((y, x),), [[x, y]]) == Array([[cos(x)*exp(y), -sin(x)*exp(y)], [sin(x)*exp(y), cos(x)*exp(y)]])
# Test different notations:
fxyz.diff(x).diff(y).diff(x) == fxyz.diff(((x, y, z),), 3)[0, 1, 0]
fxyz.diff(z).diff(y).diff(x) == fxyz.diff(((x, y, z),), 3)[2, 1, 0]
fxyz.diff([[x, y, z]], ((z, y, x),)) == Array([[fxyz.diff(i).diff(j) for i in (x, y, z)] for j in (z, y, x)])
# Test scalar derived by matrix remains matrix:
res = x.diff(Matrix([[x, y]]))
assert isinstance(res, ImmutableDenseMatrix)
assert res == Matrix([[1, 0]])
res = (x**3).diff(Matrix([[x, y]]))
assert isinstance(res, ImmutableDenseMatrix)
assert res == Matrix([[3*x**2, 0]])
def test_getattr():
A = Matrix(((1, 4, x), (y, 2, 4), (10, 5, x**2 + 1)))
raises(AttributeError, lambda: A.nonexistantattribute)
assert getattr(A, 'diff')(x) == Matrix(((0, 0, 1), (0, 0, 0), (0, 0, 2*x)))
def test_hessenberg():
A = Matrix([[3, 4, 1], [2, 4, 5], [0, 1, 2]])
assert A.is_upper_hessenberg
A = A.T
assert A.is_lower_hessenberg
A[0, -1] = 1
assert A.is_lower_hessenberg is False
A = Matrix([[3, 4, 1], [2, 4, 5], [3, 1, 2]])
assert not A.is_upper_hessenberg
A = zeros(5, 2)
assert A.is_upper_hessenberg
def test_cholesky():
raises(NonSquareMatrixError, lambda: Matrix((1, 2)).cholesky())
raises(ValueError, lambda: Matrix(((1, 2), (3, 4))).cholesky())
raises(ValueError, lambda: Matrix(((5 + I, 0), (0, 1))).cholesky())
raises(ValueError, lambda: Matrix(((1, 5), (5, 1))).cholesky())
raises(ValueError, lambda: Matrix(((1, 2), (3, 4))).cholesky(hermitian=False))
assert Matrix(((5 + I, 0), (0, 1))).cholesky(hermitian=False) == Matrix([
[sqrt(5 + I), 0], [0, 1]])
A = Matrix(((1, 5), (5, 1)))
L = A.cholesky(hermitian=False)
assert L == Matrix([[1, 0], [5, 2*sqrt(6)*I]])
assert L*L.T == A
A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
L = A.cholesky()
assert L * L.T == A
assert L.is_lower
assert L == Matrix([[5, 0, 0], [3, 3, 0], [-1, 1, 3]])
A = Matrix(((4, -2*I, 2 + 2*I), (2*I, 2, -1 + I), (2 - 2*I, -1 - I, 11)))
assert A.cholesky() == Matrix(((2, 0, 0), (I, 1, 0), (1 - I, 0, 3)))
def test_LDLdecomposition():
raises(NonSquareMatrixError, lambda: Matrix((1, 2)).LDLdecomposition())
raises(ValueError, lambda: Matrix(((1, 2), (3, 4))).LDLdecomposition())
raises(ValueError, lambda: Matrix(((5 + I, 0), (0, 1))).LDLdecomposition())
raises(ValueError, lambda: Matrix(((1, 5), (5, 1))).LDLdecomposition())
raises(ValueError, lambda: Matrix(((1, 2), (3, 4))).LDLdecomposition(hermitian=False))
A = Matrix(((1, 5), (5, 1)))
L, D = A.LDLdecomposition(hermitian=False)
assert L * D * L.T == A
A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
L, D = A.LDLdecomposition()
assert L * D * L.T == A
assert L.is_lower
assert L == Matrix([[1, 0, 0], [ S(3)/5, 1, 0], [S(-1)/5, S(1)/3, 1]])
assert D.is_diagonal()
assert D == Matrix([[25, 0, 0], [0, 9, 0], [0, 0, 9]])
A = Matrix(((4, -2*I, 2 + 2*I), (2*I, 2, -1 + I), (2 - 2*I, -1 - I, 11)))
L, D = A.LDLdecomposition()
assert expand_mul(L * D * L.H) == A
assert L == Matrix(((1, 0, 0), (I/2, 1, 0), (S(1)/2 - I/2, 0, 1)))
assert D == Matrix(((4, 0, 0), (0, 1, 0), (0, 0, 9)))
def test_cholesky_solve():
A = Matrix([[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
x = Matrix(3, 1, [3, 7, 5])
b = A*x
soln = A.cholesky_solve(b)
assert soln == x
A = Matrix([[0, -1, 2],
[5, 10, 7],
[8, 3, 4]])
x = Matrix(3, 1, [-1, 2, 5])
b = A*x
soln = A.cholesky_solve(b)
assert soln == x
A = Matrix(((1, 5), (5, 1)))
x = Matrix((4, -3))
b = A*x
soln = A.cholesky_solve(b)
assert soln == x
A = Matrix(((9, 3*I), (-3*I, 5)))
x = Matrix((-2, 1))
b = A*x
soln = A.cholesky_solve(b)
assert expand_mul(soln) == x
A = Matrix(((9*I, 3), (-3 + I, 5)))
x = Matrix((2 + 3*I, -1))
b = A*x
soln = A.cholesky_solve(b)
assert expand_mul(soln) == x
a00, a01, a11, b0, b1 = symbols('a00, a01, a11, b0, b1')
A = Matrix(((a00, a01), (a01, a11)))
b = Matrix((b0, b1))
x = A.cholesky_solve(b)
assert simplify(A*x) == b
def test_LDLsolve():
A = Matrix([[2, 3, 5],
[3, 6, 2],
[8, 3, 6]])
x = Matrix(3, 1, [3, 7, 5])
b = A*x
soln = A.LDLsolve(b)
assert soln == x
A = Matrix([[0, -1, 2],
[5, 10, 7],
[8, 3, 4]])
x = Matrix(3, 1, [-1, 2, 5])
b = A*x
soln = A.LDLsolve(b)
assert soln == x
A = Matrix(((9, 3*I), (-3*I, 5)))
x = Matrix((-2, 1))
b = A*x
soln = A.LDLsolve(b)
assert expand_mul(soln) == x
A = Matrix(((9*I, 3), (-3 + I, 5)))
x = Matrix((2 + 3*I, -1))
b = A*x
soln = A.cholesky_solve(b)
assert expand_mul(soln) == x
def test_lower_triangular_solve():
raises(NonSquareMatrixError,
lambda: Matrix([1, 0]).lower_triangular_solve(Matrix([0, 1])))
raises(ShapeError,
lambda: Matrix([[1, 0], [0, 1]]).lower_triangular_solve(Matrix([1])))
raises(ValueError,
lambda: Matrix([[2, 1], [1, 2]]).lower_triangular_solve(
Matrix([[1, 0], [0, 1]])))
A = Matrix([[1, 0], [0, 1]])
B = Matrix([[x, y], [y, x]])
C = Matrix([[4, 8], [2, 9]])
assert A.lower_triangular_solve(B) == B
assert A.lower_triangular_solve(C) == C
def test_upper_triangular_solve():
raises(NonSquareMatrixError,
lambda: Matrix([1, 0]).upper_triangular_solve(Matrix([0, 1])))
raises(TypeError,
lambda: Matrix([[1, 0], [0, 1]]).upper_triangular_solve(Matrix([1])))
raises(TypeError,
lambda: Matrix([[2, 1], [1, 2]]).upper_triangular_solve(
Matrix([[1, 0], [0, 1]])))
A = Matrix([[1, 0], [0, 1]])
B = Matrix([[x, y], [y, x]])
C = Matrix([[2, 4], [3, 8]])
assert A.upper_triangular_solve(B) == B
assert A.upper_triangular_solve(C) == C
def test_diagonal_solve():
raises(TypeError, lambda: Matrix([1, 1]).diagonal_solve(Matrix([1])))
A = Matrix([[1, 0], [0, 1]])*2
B = Matrix([[x, y], [y, x]])
assert A.diagonal_solve(B) == B/2
def test_matrix_norm():
# Vector Tests
# Test columns and symbols
x = Symbol('x', real=True)
v = Matrix([cos(x), sin(x)])
assert trigsimp(v.norm(2)) == 1
assert v.norm(10) == Pow(cos(x)**10 + sin(x)**10, S(1)/10)
# Test Rows
A = Matrix([[5, Rational(3, 2)]])
assert A.norm() == Pow(25 + Rational(9, 4), S(1)/2)
assert A.norm(oo) == max(A._mat)
assert A.norm(-oo) == min(A._mat)
# Matrix Tests
# Intuitive test
A = Matrix([[1, 1], [1, 1]])
assert A.norm(2) == 2
assert A.norm(-2) == 0
assert A.norm('frobenius') == 2
assert eye(10).norm(2) == eye(10).norm(-2) == 1
assert A.norm(oo) == 2
# Test with Symbols and more complex entries
A = Matrix([[3, y, y], [x, S(1)/2, -pi]])
assert (A.norm('fro')
== sqrt(S(37)/4 + 2*abs(y)**2 + pi**2 + x**2))
# Check non-square
A = Matrix([[1, 2, -3], [4, 5, Rational(13, 2)]])
assert A.norm(2) == sqrt(S(389)/8 + sqrt(78665)/8)
assert A.norm(-2) == S(0)
assert A.norm('frobenius') == sqrt(389)/2
# Test properties of matrix norms
# https://en.wikipedia.org/wiki/Matrix_norm#Definition
# Two matrices
A = Matrix([[1, 2], [3, 4]])
B = Matrix([[5, 5], [-2, 2]])
C = Matrix([[0, -I], [I, 0]])
D = Matrix([[1, 0], [0, -1]])
L = [A, B, C, D]
alpha = Symbol('alpha', real=True)
for order in ['fro', 2, -2]:
# Zero Check
assert zeros(3).norm(order) == S(0)
# Check Triangle Inequality for all Pairs of Matrices
for X in L:
for Y in L:
dif = (X.norm(order) + Y.norm(order) -
(X + Y).norm(order))
assert (dif >= 0)
# Scalar multiplication linearity
for M in [A, B, C, D]:
dif = simplify((alpha*M).norm(order) -
abs(alpha) * M.norm(order))
assert dif == 0
# Test Properties of Vector Norms
# https://en.wikipedia.org/wiki/Vector_norm
# Two column vectors
a = Matrix([1, 1 - 1*I, -3])
b = Matrix([S(1)/2, 1*I, 1])
c = Matrix([-1, -1, -1])
d = Matrix([3, 2, I])
e = Matrix([Integer(1e2), Rational(1, 1e2), 1])
L = [a, b, c, d, e]
alpha = Symbol('alpha', real=True)
for order in [1, 2, -1, -2, S.Infinity, S.NegativeInfinity, pi]:
# Zero Check
if order > 0:
assert Matrix([0, 0, 0]).norm(order) == S(0)
# Triangle inequality on all pairs
if order >= 1: # Triangle InEq holds only for these norms
for X in L:
for Y in L:
dif = (X.norm(order) + Y.norm(order) -
(X + Y).norm(order))
assert simplify(dif >= 0) is S.true
# Linear to scalar multiplication
if order in [1, 2, -1, -2, S.Infinity, S.NegativeInfinity]:
for X in L:
dif = simplify((alpha*X).norm(order) -
(abs(alpha) * X.norm(order)))
assert dif == 0
# ord=1
M = Matrix(3, 3, [1, 3, 0, -2, -1, 0, 3, 9, 6])
assert M.norm(1) == 13
def test_condition_number():
x = Symbol('x', real=True)
A = eye(3)
A[0, 0] = 10
A[2, 2] = S(1)/10
assert A.condition_number() == 100
A[1, 1] = x
assert A.condition_number() == Max(10, Abs(x)) / Min(S(1)/10, Abs(x))
M = Matrix([[cos(x), sin(x)], [-sin(x), cos(x)]])
Mc = M.condition_number()
assert all(Float(1.).epsilon_eq(Mc.subs(x, val).evalf()) for val in
[Rational(1, 5), Rational(1, 2), Rational(1, 10), pi/2, pi, 7*pi/4 ])
#issue 10782
assert Matrix([]).condition_number() == 0
def test_equality():
A = Matrix(((1, 2, 3), (4, 5, 6), (7, 8, 9)))
B = Matrix(((9, 8, 7), (6, 5, 4), (3, 2, 1)))
assert A == A[:, :]
assert not A != A[:, :]
assert not A == B
assert A != B
assert A != 10
assert not A == 10
# A SparseMatrix can be equal to a Matrix
C = SparseMatrix(((1, 0, 0), (0, 1, 0), (0, 0, 1)))
D = Matrix(((1, 0, 0), (0, 1, 0), (0, 0, 1)))
assert C == D
assert not C != D
def test_col_join():
assert eye(3).col_join(Matrix([[7, 7, 7]])) == \
Matrix([[1, 0, 0],
[0, 1, 0],
[0, 0, 1],
[7, 7, 7]])
def test_row_insert():
r4 = Matrix([[4, 4, 4]])
for i in range(-4, 5):
l = [1, 0, 0]
l.insert(i, 4)
assert flatten(eye(3).row_insert(i, r4).col(0).tolist()) == l
def test_col_insert():
c4 = Matrix([4, 4, 4])
for i in range(-4, 5):
l = [0, 0, 0]
l.insert(i, 4)
assert flatten(zeros(3).col_insert(i, c4).row(0).tolist()) == l
def test_normalized():
assert Matrix([3, 4]).normalized() == \
Matrix([Rational(3, 5), Rational(4, 5)])
def test_print_nonzero():
assert capture(lambda: eye(3).print_nonzero()) == \
'[X ]\n[ X ]\n[ X]\n'
assert capture(lambda: eye(3).print_nonzero('.')) == \
'[. ]\n[ . ]\n[ .]\n'
def test_zeros_eye():
assert Matrix.eye(3) == eye(3)
assert Matrix.zeros(3) == zeros(3)
assert ones(3, 4) == Matrix(3, 4, [1]*12)
i = Matrix([[1, 0], [0, 1]])
z = Matrix([[0, 0], [0, 0]])
for cls in classes:
m = cls.eye(2)
assert i == m # but m == i will fail if m is immutable
assert i == eye(2, cls=cls)
assert type(m) == cls
m = cls.zeros(2)
assert z == m
assert z == zeros(2, cls=cls)
assert type(m) == cls
def test_is_zero():
assert Matrix().is_zero
assert Matrix([[0, 0], [0, 0]]).is_zero
assert zeros(3, 4).is_zero
assert not eye(3).is_zero
assert Matrix([[x, 0], [0, 0]]).is_zero == None
assert SparseMatrix([[x, 0], [0, 0]]).is_zero == None
assert ImmutableMatrix([[x, 0], [0, 0]]).is_zero == None
assert ImmutableSparseMatrix([[x, 0], [0, 0]]).is_zero == None
assert Matrix([[x, 1], [0, 0]]).is_zero == False
a = Symbol('a', nonzero=True)
assert Matrix([[a, 0], [0, 0]]).is_zero == False
def test_rotation_matrices():
# This tests the rotation matrices by rotating about an axis and back.
theta = pi/3
r3_plus = rot_axis3(theta)
r3_minus = rot_axis3(-theta)
r2_plus = rot_axis2(theta)
r2_minus = rot_axis2(-theta)
r1_plus = rot_axis1(theta)
r1_minus = rot_axis1(-theta)
assert r3_minus*r3_plus*eye(3) == eye(3)
assert r2_minus*r2_plus*eye(3) == eye(3)
assert r1_minus*r1_plus*eye(3) == eye(3)
# Check the correctness of the trace of the rotation matrix
assert r1_plus.trace() == 1 + 2*cos(theta)
assert r2_plus.trace() == 1 + 2*cos(theta)
assert r3_plus.trace() == 1 + 2*cos(theta)
# Check that a rotation with zero angle doesn't change anything.
assert rot_axis1(0) == eye(3)
assert rot_axis2(0) == eye(3)
assert rot_axis3(0) == eye(3)
def test_DeferredVector():
assert str(DeferredVector("vector")[4]) == "vector[4]"
assert sympify(DeferredVector("d")) == DeferredVector("d")
def test_DeferredVector_not_iterable():
assert not iterable(DeferredVector('X'))
def test_DeferredVector_Matrix():
raises(TypeError, lambda: Matrix(DeferredVector("V")))
def test_GramSchmidt():
R = Rational
m1 = Matrix(1, 2, [1, 2])
m2 = Matrix(1, 2, [2, 3])
assert GramSchmidt([m1, m2]) == \
[Matrix(1, 2, [1, 2]), Matrix(1, 2, [R(2)/5, R(-1)/5])]
assert GramSchmidt([m1.T, m2.T]) == \
[Matrix(2, 1, [1, 2]), Matrix(2, 1, [R(2)/5, R(-1)/5])]
# from wikipedia
assert GramSchmidt([Matrix([3, 1]), Matrix([2, 2])], True) == [
Matrix([3*sqrt(10)/10, sqrt(10)/10]),
Matrix([-sqrt(10)/10, 3*sqrt(10)/10])]
def test_casoratian():
assert casoratian([1, 2, 3, 4], 1) == 0
assert casoratian([1, 2, 3, 4], 1, zero=False) == 0
def test_zero_dimension_multiply():
assert (Matrix()*zeros(0, 3)).shape == (0, 3)
assert zeros(3, 0)*zeros(0, 3) == zeros(3, 3)
assert zeros(0, 3)*zeros(3, 0) == Matrix()
def test_slice_issue_2884():
m = Matrix(2, 2, range(4))
assert m[1, :] == Matrix([[2, 3]])
assert m[-1, :] == Matrix([[2, 3]])
assert m[:, 1] == Matrix([[1, 3]]).T
assert m[:, -1] == Matrix([[1, 3]]).T
raises(IndexError, lambda: m[2, :])
raises(IndexError, lambda: m[2, 2])
def test_slice_issue_3401():
assert zeros(0, 3)[:, -1].shape == (0, 1)
assert zeros(3, 0)[0, :] == Matrix(1, 0, [])
def test_copyin():
s = zeros(3, 3)
s[3] = 1
assert s[:, 0] == Matrix([0, 1, 0])
assert s[3] == 1
assert s[3: 4] == [1]
s[1, 1] = 42
assert s[1, 1] == 42
assert s[1, 1:] == Matrix([[42, 0]])
s[1, 1:] = Matrix([[5, 6]])
assert s[1, :] == Matrix([[1, 5, 6]])
s[1, 1:] = [[42, 43]]
assert s[1, :] == Matrix([[1, 42, 43]])
s[0, 0] = 17
assert s[:, :1] == Matrix([17, 1, 0])
s[0, 0] = [1, 1, 1]
assert s[:, 0] == Matrix([1, 1, 1])
s[0, 0] = Matrix([1, 1, 1])
assert s[:, 0] == Matrix([1, 1, 1])
s[0, 0] = SparseMatrix([1, 1, 1])
assert s[:, 0] == Matrix([1, 1, 1])
def test_invertible_check():
# sometimes a singular matrix will have a pivot vector shorter than
# the number of rows in a matrix...
assert Matrix([[1, 2], [1, 2]]).rref() == (Matrix([[1, 2], [0, 0]]), (0,))
raises(ValueError, lambda: Matrix([[1, 2], [1, 2]]).inv())
m = Matrix([
[-1, -1, 0],
[ x, 1, 1],
[ 1, x, -1],
])
assert len(m.rref()[1]) != m.rows
# in addition, unless simplify=True in the call to rref, the identity
# matrix will be returned even though m is not invertible
assert m.rref()[0] != eye(3)
assert m.rref(simplify=signsimp)[0] != eye(3)
raises(ValueError, lambda: m.inv(method="ADJ"))
raises(ValueError, lambda: m.inv(method="GE"))
raises(ValueError, lambda: m.inv(method="LU"))
@XFAIL
def test_issue_3959():
x, y = symbols('x, y')
e = x*y
assert e.subs(x, Matrix([3, 5, 3])) == Matrix([3, 5, 3])*y
def test_issue_5964():
assert str(Matrix([[1, 2], [3, 4]])) == 'Matrix([[1, 2], [3, 4]])'
def test_issue_7604():
x, y = symbols(u"x y")
assert sstr(Matrix([[x, 2*y], [y**2, x + 3]])) == \
'Matrix([\n[ x, 2*y],\n[y**2, x + 3]])'
def test_is_Identity():
assert eye(3).is_Identity
assert eye(3).as_immutable().is_Identity
assert not zeros(3).is_Identity
assert not ones(3).is_Identity
# issue 6242
assert not Matrix([[1, 0, 0]]).is_Identity
# issue 8854
assert SparseMatrix(3,3, {(0,0):1, (1,1):1, (2,2):1}).is_Identity
assert not SparseMatrix(2,3, range(6)).is_Identity
assert not SparseMatrix(3,3, {(0,0):1, (1,1):1}).is_Identity
assert not SparseMatrix(3,3, {(0,0):1, (1,1):1, (2,2):1, (0,1):2, (0,2):3}).is_Identity
def test_dot():
assert ones(1, 3).dot(ones(3, 1)) == 3
assert ones(1, 3).dot([1, 1, 1]) == 3
assert Matrix([1, 2, 3]).dot(Matrix([1, 2, 3])) == 14
assert Matrix([1, 2, 3*I]).dot(Matrix([I, 2, 3*I])) == -5 + I
assert Matrix([1, 2, 3*I]).dot(Matrix([I, 2, 3*I]), hermitian=False) == -5 + I
assert Matrix([1, 2, 3*I]).dot(Matrix([I, 2, 3*I]), hermitian=True) == 13 + I
assert Matrix([1, 2, 3*I]).dot(Matrix([I, 2, 3*I]), hermitian=True, conjugate_convention="physics") == 13 - I
assert Matrix([1, 2, 3*I]).dot(Matrix([4, 5*I, 6]), hermitian=True, conjugate_convention="right") == 4 + 8*I
assert Matrix([1, 2, 3*I]).dot(Matrix([4, 5*I, 6]), hermitian=True, conjugate_convention="left") == 4 - 8*I
assert Matrix([I, 2*I]).dot(Matrix([I, 2*I]), hermitian=False, conjugate_convention="left") == -5
assert Matrix([I, 2*I]).dot(Matrix([I, 2*I]), conjugate_convention="left") == 5
def test_dual():
B_x, B_y, B_z, E_x, E_y, E_z = symbols(
'B_x B_y B_z E_x E_y E_z', real=True)
F = Matrix((
( 0, E_x, E_y, E_z),
(-E_x, 0, B_z, -B_y),
(-E_y, -B_z, 0, B_x),
(-E_z, B_y, -B_x, 0)
))
Fd = Matrix((
( 0, -B_x, -B_y, -B_z),
(B_x, 0, E_z, -E_y),
(B_y, -E_z, 0, E_x),
(B_z, E_y, -E_x, 0)
))
assert F.dual().equals(Fd)
assert eye(3).dual().equals(zeros(3))
assert F.dual().dual().equals(-F)
def test_anti_symmetric():
assert Matrix([1, 2]).is_anti_symmetric() is False
m = Matrix(3, 3, [0, x**2 + 2*x + 1, y, -(x + 1)**2, 0, x*y, -y, -x*y, 0])
assert m.is_anti_symmetric() is True
assert m.is_anti_symmetric(simplify=False) is False
assert m.is_anti_symmetric(simplify=lambda x: x) is False
# tweak to fail
m[2, 1] = -m[2, 1]
assert m.is_anti_symmetric() is False
# untweak
m[2, 1] = -m[2, 1]
m = m.expand()
assert m.is_anti_symmetric(simplify=False) is True
m[0, 0] = 1
assert m.is_anti_symmetric() is False
def test_normalize_sort_diogonalization():
A = Matrix(((1, 2), (2, 1)))
P, Q = A.diagonalize(normalize=True)
assert P*P.T == P.T*P == eye(P.cols)
P, Q = A.diagonalize(normalize=True, sort=True)
assert P*P.T == P.T*P == eye(P.cols)
assert P*Q*P.inv() == A
def test_issue_5321():
raises(ValueError, lambda: Matrix([[1, 2, 3], Matrix(0, 1, [])]))
def test_issue_5320():
assert Matrix.hstack(eye(2), 2*eye(2)) == Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2]
])
assert Matrix.vstack(eye(2), 2*eye(2)) == Matrix([
[1, 0],
[0, 1],
[2, 0],
[0, 2]
])
cls = SparseMatrix
assert cls.hstack(cls(eye(2)), cls(2*eye(2))) == Matrix([
[1, 0, 2, 0],
[0, 1, 0, 2]
])
def test_issue_11944():
A = Matrix([[1]])
AIm = sympify(A)
assert Matrix.hstack(AIm, A) == Matrix([[1, 1]])
assert Matrix.vstack(AIm, A) == Matrix([[1], [1]])
def test_cross():
a = [1, 2, 3]
b = [3, 4, 5]
col = Matrix([-2, 4, -2])
row = col.T
def test(M, ans):
assert ans == M
assert type(M) == cls
for cls in classes:
A = cls(a)
B = cls(b)
test(A.cross(B), col)
test(A.cross(B.T), col)
test(A.T.cross(B.T), row)
test(A.T.cross(B), row)
raises(ShapeError, lambda:
Matrix(1, 2, [1, 1]).cross(Matrix(1, 2, [1, 1])))
def test_hash():
for cls in classes[-2:]:
s = {cls.eye(1), cls.eye(1)}
assert len(s) == 1 and s.pop() == cls.eye(1)
# issue 3979
for cls in classes[:2]:
assert not isinstance(cls.eye(1), Hashable)
@XFAIL
def test_issue_3979():
# when this passes, delete this and change the [1:2]
# to [:2] in the test_hash above for issue 3979
cls = classes[0]
raises(AttributeError, lambda: hash(cls.eye(1)))
def test_adjoint():
dat = [[0, I], [1, 0]]
ans = Matrix([[0, 1], [-I, 0]])
for cls in classes:
assert ans == cls(dat).adjoint()
def test_simplify_immutable():
from sympy import simplify, sin, cos
assert simplify(ImmutableMatrix([[sin(x)**2 + cos(x)**2]])) == \
ImmutableMatrix([[1]])
def test_rank():
from sympy.abc import x
m = Matrix([[1, 2], [x, 1 - 1/x]])
assert m.rank() == 2
n = Matrix(3, 3, range(1, 10))
assert n.rank() == 2
p = zeros(3)
assert p.rank() == 0
def test_issue_11434():
ax, ay, bx, by, cx, cy, dx, dy, ex, ey, t0, t1 = \
symbols('a_x a_y b_x b_y c_x c_y d_x d_y e_x e_y t_0 t_1')
M = Matrix([[ax, ay, ax*t0, ay*t0, 0],
[bx, by, bx*t0, by*t0, 0],
[cx, cy, cx*t0, cy*t0, 1],
[dx, dy, dx*t0, dy*t0, 1],
[ex, ey, 2*ex*t1 - ex*t0, 2*ey*t1 - ey*t0, 0]])
assert M.rank() == 4
def test_rank_regression_from_so():
# see:
# https://stackoverflow.com/questions/19072700/why-does-sympy-give-me-the-wrong-answer-when-i-row-reduce-a-symbolic-matrix
nu, lamb = symbols('nu, lambda')
A = Matrix([[-3*nu, 1, 0, 0],
[ 3*nu, -2*nu - 1, 2, 0],
[ 0, 2*nu, (-1*nu) - lamb - 2, 3],
[ 0, 0, nu + lamb, -3]])
expected_reduced = Matrix([[1, 0, 0, 1/(nu**2*(-lamb - nu))],
[0, 1, 0, 3/(nu*(-lamb - nu))],
[0, 0, 1, 3/(-lamb - nu)],
[0, 0, 0, 0]])
expected_pivots = (0, 1, 2)
reduced, pivots = A.rref()
assert simplify(expected_reduced - reduced) == zeros(*A.shape)
assert pivots == expected_pivots
def test_replace():
from sympy import symbols, Function, Matrix
F, G = symbols('F, G', cls=Function)
K = Matrix(2, 2, lambda i, j: G(i+j))
M = Matrix(2, 2, lambda i, j: F(i+j))
N = M.replace(F, G)
assert N == K
def test_replace_map():
from sympy import symbols, Function, Matrix
F, G = symbols('F, G', cls=Function)
K = Matrix(2, 2, [(G(0), {F(0): G(0)}), (G(1), {F(1): G(1)}), (G(1), {F(1)\
: G(1)}), (G(2), {F(2): G(2)})])
M = Matrix(2, 2, lambda i, j: F(i+j))
N = M.replace(F, G, True)
assert N == K
def test_atoms():
m = Matrix([[1, 2], [x, 1 - 1/x]])
assert m.atoms() == {S(1),S(2),S(-1), x}
assert m.atoms(Symbol) == {x}
@slow
def test_pinv():
# Pseudoinverse of an invertible matrix is the inverse.
A1 = Matrix([[a, b], [c, d]])
assert simplify(A1.pinv()) == simplify(A1.inv())
# Test the four properties of the pseudoinverse for various matrices.
As = [Matrix([[13, 104], [2212, 3], [-3, 5]]),
Matrix([[1, 7, 9], [11, 17, 19]]),
Matrix([a, b])]
for A in As:
A_pinv = A.pinv()
AAp = A * A_pinv
ApA = A_pinv * A
assert simplify(AAp * A) == A
assert simplify(ApA * A_pinv) == A_pinv
assert AAp.H == AAp
assert ApA.H == ApA
def test_pinv_solve():
# Fully determined system (unique result, identical to other solvers).
A = Matrix([[1, 5], [7, 9]])
B = Matrix([12, 13])
assert A.pinv_solve(B) == A.cholesky_solve(B)
assert A.pinv_solve(B) == A.LDLsolve(B)
assert A.pinv_solve(B) == Matrix([sympify('-43/26'), sympify('71/26')])
assert A * A.pinv() * B == B
# Fully determined, with two-dimensional B matrix.
B = Matrix([[12, 13, 14], [15, 16, 17]])
assert A.pinv_solve(B) == A.cholesky_solve(B)
assert A.pinv_solve(B) == A.LDLsolve(B)
assert A.pinv_solve(B) == Matrix([[-33, -37, -41], [69, 75, 81]]) / 26
assert A * A.pinv() * B == B
# Underdetermined system (infinite results).
A = Matrix([[1, 0, 1], [0, 1, 1]])
B = Matrix([5, 7])
solution = A.pinv_solve(B)
w = {}
for s in solution.atoms(Symbol):
# Extract dummy symbols used in the solution.
w[s.name] = s
assert solution == Matrix([[w['w0_0']/3 + w['w1_0']/3 - w['w2_0']/3 + 1],
[w['w0_0']/3 + w['w1_0']/3 - w['w2_0']/3 + 3],
[-w['w0_0']/3 - w['w1_0']/3 + w['w2_0']/3 + 4]])
assert A * A.pinv() * B == B
# Overdetermined system (least squares results).
A = Matrix([[1, 0], [0, 0], [0, 1]])
B = Matrix([3, 2, 1])
assert A.pinv_solve(B) == Matrix([3, 1])
# Proof the solution is not exact.
assert A * A.pinv() * B != B
def test_pinv_rank_deficient():
# Test the four properties of the pseudoinverse for various matrices.
As = [Matrix([[1, 1, 1], [2, 2, 2]]),
Matrix([[1, 0], [0, 0]]),
Matrix([[1, 2], [2, 4], [3, 6]])]
for A in As:
A_pinv = A.pinv()
AAp = A * A_pinv
ApA = A_pinv * A
assert simplify(AAp * A) == A
assert simplify(ApA * A_pinv) == A_pinv
assert AAp.H == AAp
assert ApA.H == ApA
# Test solving with rank-deficient matrices.
A = Matrix([[1, 0], [0, 0]])
# Exact, non-unique solution.
B = Matrix([3, 0])
solution = A.pinv_solve(B)
w1 = solution.atoms(Symbol).pop()
assert w1.name == 'w1_0'
assert solution == Matrix([3, w1])
assert A * A.pinv() * B == B
# Least squares, non-unique solution.
B = Matrix([3, 1])
solution = A.pinv_solve(B)
w1 = solution.atoms(Symbol).pop()
assert w1.name == 'w1_0'
assert solution == Matrix([3, w1])
assert A * A.pinv() * B != B
@XFAIL
def test_pinv_rank_deficient_when_diagonalization_fails():
print('Test the four properties of the pseudoinverse for matrices when diagonalization of A.H*A fails.')
As = [Matrix([
[61, 89, 55, 20, 71, 0],
[62, 96, 85, 85, 16, 0],
[69, 56, 17, 4, 54, 0],
[10, 54, 91, 41, 71, 0],
[ 7, 30, 10, 48, 90, 0],
[0,0,0,0,0,0]])]
for A in As:
A_pinv = A.pinv()
AAp = A * A_pinv
ApA = A_pinv * A
assert simplify(AAp * A) == A
assert simplify(ApA * A_pinv) == A_pinv
assert AAp.H == AAp
assert ApA.H == ApA
def test_gauss_jordan_solve():
# Square, full rank, unique solution
A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 10]])
b = Matrix([3, 6, 9])
sol, params = A.gauss_jordan_solve(b)
assert sol == Matrix([[-1], [2], [0]])
assert params == Matrix(0, 1, [])
# Square, reduced rank, parametrized solution
A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
b = Matrix([3, 6, 9])
sol, params, freevar = A.gauss_jordan_solve(b, freevar=True)
w = {}
for s in sol.atoms(Symbol):
# Extract dummy symbols used in the solution.
w[s.name] = s
assert sol == Matrix([[w['tau0'] - 1], [-2*w['tau0'] + 2], [w['tau0']]])
assert params == Matrix([[w['tau0']]])
assert freevar == [2]
# Square, reduced rank, parametrized solution
A = Matrix([[1, 2, 3], [2, 4, 6], [3, 6, 9]])
b = Matrix([0, 0, 0])
sol, params = A.gauss_jordan_solve(b)
w = {}
for s in sol.atoms(Symbol):
w[s.name] = s
assert sol == Matrix([[-2*w['tau0'] - 3*w['tau1']],
[w['tau0']], [w['tau1']]])
assert params == Matrix([[w['tau0']], [w['tau1']]])
# Square, reduced rank, parametrized solution
A = Matrix([[0, 0, 0], [0, 0, 0], [0, 0, 0]])
b = Matrix([0, 0, 0])
sol, params = A.gauss_jordan_solve(b)
w = {}
for s in sol.atoms(Symbol):
w[s.name] = s
assert sol == Matrix([[w['tau0']], [w['tau1']], [w['tau2']]])
assert params == Matrix([[w['tau0']], [w['tau1']], [w['tau2']]])
# Square, reduced rank, no solution
A = Matrix([[1, 2, 3], [2, 4, 6], [3, 6, 9]])
b = Matrix([0, 0, 1])
raises(ValueError, lambda: A.gauss_jordan_solve(b))
# Rectangular, tall, full rank, unique solution
A = Matrix([[1, 5, 3], [2, 1, 6], [1, 7, 9], [1, 4, 3]])
b = Matrix([0, 0, 1, 0])
sol, params = A.gauss_jordan_solve(b)
assert sol == Matrix([[-S(1)/2], [0], [S(1)/6]])
assert params == Matrix(0, 1, [])
# Rectangular, tall, full rank, no solution
A = Matrix([[1, 5, 3], [2, 1, 6], [1, 7, 9], [1, 4, 3]])
b = Matrix([0, 0, 0, 1])
raises(ValueError, lambda: A.gauss_jordan_solve(b))
# Rectangular, tall, reduced rank, parametrized solution
A = Matrix([[1, 5, 3], [2, 10, 6], [3, 15, 9], [1, 4, 3]])
b = Matrix([0, 0, 0, 1])
sol, params = A.gauss_jordan_solve(b)
w = {}
for s in sol.atoms(Symbol):
w[s.name] = s
assert sol == Matrix([[-3*w['tau0'] + 5], [-1], [w['tau0']]])
assert params == Matrix([[w['tau0']]])
# Rectangular, tall, reduced rank, no solution
A = Matrix([[1, 5, 3], [2, 10, 6], [3, 15, 9], [1, 4, 3]])
b = Matrix([0, 0, 1, 1])
raises(ValueError, lambda: A.gauss_jordan_solve(b))
# Rectangular, wide, full rank, parametrized solution
A = Matrix([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 1, 12]])
b = Matrix([1, 1, 1])
sol, params = A.gauss_jordan_solve(b)
w = {}
for s in sol.atoms(Symbol):
w[s.name] = s
assert sol == Matrix([[2*w['tau0'] - 1], [-3*w['tau0'] + 1], [0],
[w['tau0']]])
assert params == Matrix([[w['tau0']]])
# Rectangular, wide, reduced rank, parametrized solution
A = Matrix([[1, 2, 3, 4], [5, 6, 7, 8], [2, 4, 6, 8]])
b = Matrix([0, 1, 0])
sol, params = A.gauss_jordan_solve(b)
w = {}
for s in sol.atoms(Symbol):
w[s.name] = s
assert sol == Matrix([[w['tau0'] + 2*w['tau1'] + 1/S(2)],
[-2*w['tau0'] - 3*w['tau1'] - 1/S(4)],
[w['tau0']], [w['tau1']]])
assert params == Matrix([[w['tau0']], [w['tau1']]])
# watch out for clashing symbols
x0, x1, x2, _x0 = symbols('_tau0 _tau1 _tau2 tau1')
M = Matrix([[0, 1, 0, 0, 0, 0], [0, 0, 0, 1, 0, _x0]])
A = M[:, :-1]
b = M[:, -1:]
sol, params = A.gauss_jordan_solve(b)
assert params == Matrix(3, 1, [x0, x1, x2])
assert sol == Matrix(5, 1, [x1, 0, x0, _x0, x2])
# Rectangular, wide, reduced rank, no solution
A = Matrix([[1, 2, 3, 4], [5, 6, 7, 8], [2, 4, 6, 8]])
b = Matrix([1, 1, 1])
raises(ValueError, lambda: A.gauss_jordan_solve(b))
def test_solve():
A = Matrix([[1,2], [2,4]])
b = Matrix([[3], [4]])
raises(ValueError, lambda: A.solve(b)) #no solution
b = Matrix([[ 4], [8]])
raises(ValueError, lambda: A.solve(b)) #infinite solution
def test_issue_7201():
assert ones(0, 1) + ones(0, 1) == Matrix(0, 1, [])
assert ones(1, 0) + ones(1, 0) == Matrix(1, 0, [])
def test_free_symbols():
for M in ImmutableMatrix, ImmutableSparseMatrix, Matrix, SparseMatrix:
assert M([[x], [0]]).free_symbols == {x}
def test_from_ndarray():
"""See issue 7465."""
try:
from numpy import array
except ImportError:
skip('NumPy must be available to test creating matrices from ndarrays')
assert Matrix(array([1, 2, 3])) == Matrix([1, 2, 3])
assert Matrix(array([[1, 2, 3]])) == Matrix([[1, 2, 3]])
assert Matrix(array([[1, 2, 3], [4, 5, 6]])) == \
Matrix([[1, 2, 3], [4, 5, 6]])
assert Matrix(array([x, y, z])) == Matrix([x, y, z])
raises(NotImplementedError, lambda: Matrix(array([[
[1, 2], [3, 4]], [[5, 6], [7, 8]]])))
def test_hermitian():
a = Matrix([[1, I], [-I, 1]])
assert a.is_hermitian
a[0, 0] = 2*I
assert a.is_hermitian is False
a[0, 0] = x
assert a.is_hermitian is None
a[0, 1] = a[1, 0]*I
assert a.is_hermitian is False
def test_doit():
a = Matrix([[Add(x,x, evaluate=False)]])
assert a[0] != 2*x
assert a.doit() == Matrix([[2*x]])
def test_issue_9457_9467_9876():
# for row_del(index)
M = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
M.row_del(1)
assert M == Matrix([[1, 2, 3], [3, 4, 5]])
N = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
N.row_del(-2)
assert N == Matrix([[1, 2, 3], [3, 4, 5]])
O = Matrix([[1, 2, 3], [5, 6, 7], [9, 10, 11]])
O.row_del(-1)
assert O == Matrix([[1, 2, 3], [5, 6, 7]])
P = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(IndexError, lambda: P.row_del(10))
Q = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(IndexError, lambda: Q.row_del(-10))
# for col_del(index)
M = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
M.col_del(1)
assert M == Matrix([[1, 3], [2, 4], [3, 5]])
N = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
N.col_del(-2)
assert N == Matrix([[1, 3], [2, 4], [3, 5]])
P = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(IndexError, lambda: P.col_del(10))
Q = Matrix([[1, 2, 3], [2, 3, 4], [3, 4, 5]])
raises(IndexError, lambda: Q.col_del(-10))
def test_issue_9422():
x, y = symbols('x y', commutative=False)
a, b = symbols('a b')
M = eye(2)
M1 = Matrix(2, 2, [x, y, y, z])
assert y*x*M != x*y*M
assert b*a*M == a*b*M
assert x*M1 != M1*x
assert a*M1 == M1*a
assert y*x*M == Matrix([[y*x, 0], [0, y*x]])
def test_issue_10770():
M = Matrix([])
a = ['col_insert', 'row_join'], Matrix([9, 6, 3])
b = ['row_insert', 'col_join'], a[1].T
c = ['row_insert', 'col_insert'], Matrix([[1, 2], [3, 4]])
for ops, m in (a, b, c):
for op in ops:
f = getattr(M, op)
new = f(m) if 'join' in op else f(42, m)
assert new == m and id(new) != id(m)
def test_issue_10658():
A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
assert A.extract([0, 1, 2], [True, True, False]) == \
Matrix([[1, 2], [4, 5], [7, 8]])
assert A.extract([0, 1, 2], [True, False, False]) == Matrix([[1], [4], [7]])
assert A.extract([True, False, False], [0, 1, 2]) == Matrix([[1, 2, 3]])
assert A.extract([True, False, True], [0, 1, 2]) == \
Matrix([[1, 2, 3], [7, 8, 9]])
assert A.extract([0, 1, 2], [False, False, False]) == Matrix(3, 0, [])
assert A.extract([False, False, False], [0, 1, 2]) == Matrix(0, 3, [])
assert A.extract([True, False, True], [False, True, False]) == \
Matrix([[2], [8]])
def test_opportunistic_simplification():
# this test relates to issue #10718, #9480, #11434
# issue #9480
m = Matrix([[-5 + 5*sqrt(2), -5], [-5*sqrt(2)/2 + 5, -5*sqrt(2)/2]])
assert m.rank() == 1
# issue #10781
m = Matrix([[3+3*sqrt(3)*I, -9],[4,-3+3*sqrt(3)*I]])
assert simplify(m.rref()[0] - Matrix([[1, -9/(3 + 3*sqrt(3)*I)], [0, 0]])) == zeros(2, 2)
# issue #11434
ax,ay,bx,by,cx,cy,dx,dy,ex,ey,t0,t1 = symbols('a_x a_y b_x b_y c_x c_y d_x d_y e_x e_y t_0 t_1')
m = Matrix([[ax,ay,ax*t0,ay*t0,0],[bx,by,bx*t0,by*t0,0],[cx,cy,cx*t0,cy*t0,1],[dx,dy,dx*t0,dy*t0,1],[ex,ey,2*ex*t1-ex*t0,2*ey*t1-ey*t0,0]])
assert m.rank() == 4
def test_partial_pivoting():
# example from https://en.wikipedia.org/wiki/Pivot_element
# partial pivoting with back subsitution gives a perfect result
# naive pivoting give an error ~1e-13, so anything better than
# 1e-15 is good
mm=Matrix([[0.003 ,59.14, 59.17],[ 5.291, -6.13,46.78]])
assert (mm.rref()[0] - Matrix([[1.0, 0, 10.0], [ 0, 1.0, 1.0]])).norm() < 1e-15
# issue #11549
m_mixed = Matrix([[6e-17, 1.0, 4],[ -1.0, 0, 8],[ 0, 0, 1]])
m_float = Matrix([[6e-17, 1.0, 4.],[ -1.0, 0., 8.],[ 0., 0., 1.]])
m_inv = Matrix([[ 0, -1.0, 8.0],[1.0, 6.0e-17, -4.0],[ 0, 0, 1]])
# this example is numerically unstable and involves a matrix with a norm >= 8,
# this comparing the difference of the results with 1e-15 is numerically sound.
assert (m_mixed.inv() - m_inv).norm() < 1e-15
assert (m_float.inv() - m_inv).norm() < 1e-15
def test_iszero_substitution():
""" When doing numerical computations, all elements that pass
the iszerofunc test should be set to numerically zero if they
aren't already. """
# Matrix from issue #9060
m = Matrix([[0.9, -0.1, -0.2, 0],[-0.8, 0.9, -0.4, 0],[-0.1, -0.8, 0.6, 0]])
m_rref = m.rref(iszerofunc=lambda x: abs(x)<6e-15)[0]
m_correct = Matrix([[1.0, 0, -0.301369863013699, 0],[ 0, 1.0, -0.712328767123288, 0],[ 0, 0, 0, 0]])
m_diff = m_rref - m_correct
assert m_diff.norm() < 1e-15
# if a zero-substitution wasn't made, this entry will be -1.11022302462516e-16
assert m_rref[2,2] == 0
@slow
def test_issue_11238():
from sympy import Point
xx = 8*tan(13*pi/45)/(tan(13*pi/45) + sqrt(3))
yy = (-8*sqrt(3)*tan(13*pi/45)**2 + 24*tan(13*pi/45))/(-3 + tan(13*pi/45)**2)
p1 = Point(0, 0)
p2 = Point(1, -sqrt(3))
p0 = Point(xx,yy)
m1 = Matrix([p1 - simplify(p0), p2 - simplify(p0)])
m2 = Matrix([p1 - p0, p2 - p0])
m3 = Matrix([simplify(p1 - p0), simplify(p2 - p0)])
assert m1.rank(simplify=True) == 1
assert m2.rank(simplify=True) == 1
assert m3.rank(simplify=True) == 1
def test_as_real_imag():
m1 = Matrix(2,2,[1,2,3,4])
m2 = m1*S.ImaginaryUnit
m3 = m1 + m2
for kls in classes:
a,b = kls(m3).as_real_imag()
assert list(a) == list(m1)
assert list(b) == list(m1)
def test_deprecated():
# Maintain tests for deprecated functions. We must capture
# the deprecation warnings. When the deprecated functionality is
# removed, the corresponding tests should be removed.
m = Matrix(3, 3, [0, 1, 0, -4, 4, 0, -2, 1, 2])
P, Jcells = m.jordan_cells()
assert Jcells[1] == Matrix(1, 1, [2])
assert Jcells[0] == Matrix(2, 2, [2, 1, 0, 2])
with warns_deprecated_sympy():
assert Matrix([[1,2],[3,4]]).dot(Matrix([[1,3],[4,5]])) == [10, 19, 14, 28]
def test_issue_14489():
from sympy import Mod
A = Matrix([-1, 1, 2])
B = Matrix([10, 20, -15])
assert Mod(A, 3) == Matrix([2, 1, 2])
assert Mod(B, 4) == Matrix([2, 0, 1])
def test_issue_14517():
M = Matrix([
[ 0, 10*I, 10*I, 0],
[10*I, 0, 0, 10*I],
[10*I, 0, 5 + 2*I, 10*I],
[ 0, 10*I, 10*I, 5 + 2*I]])
ev = M.eigenvals()
# test one random eigenvalue, the computation is a little slow
test_ev = random.choice(list(ev.keys()))
assert (M - test_ev*eye(4)).det() == 0
def test_issue_14943():
# Test that __array__ accepts the optional dtype argument
try:
from numpy import array
except ImportError:
skip('NumPy must be available to test creating matrices from ndarrays')
M = Matrix([[1,2], [3,4]])
assert array(M, dtype=float).dtype.name == 'float64'
def test_issue_8240():
# Eigenvalues of large triangular matrices
n = 200
diagonal_variables = [Symbol('x%s' % i) for i in range(n)]
M = [[0 for i in range(n)] for j in range(n)]
for i in range(n):
M[i][i] = diagonal_variables[i]
M = Matrix(M)
eigenvals = M.eigenvals()
assert len(eigenvals) == n
for i in range(n):
assert eigenvals[diagonal_variables[i]] == 1
eigenvals = M.eigenvals(multiple=True)
assert set(eigenvals) == set(diagonal_variables)
# with multiplicity
M = Matrix([[x, 0, 0], [1, y, 0], [2, 3, x]])
eigenvals = M.eigenvals()
assert eigenvals == {x: 2, y: 1}
eigenvals = M.eigenvals(multiple=True)
assert len(eigenvals) == 3
assert eigenvals.count(x) == 2
assert eigenvals.count(y) == 1
def test_legacy_det():
# Minimal support for legacy keys for 'method' in det()
# Partially copied from test_determinant()
M = Matrix(( ( 3, -2, 0, 5),
(-2, 1, -2, 2),
( 0, -2, 5, 0),
( 5, 0, 3, 4) ))
assert M.det(method="bareis") == -289
assert M.det(method="det_lu") == -289
assert M.det(method="det_LU") == -289
M = Matrix(( (3, 2, 0, 0, 0),
(0, 3, 2, 0, 0),
(0, 0, 3, 2, 0),
(0, 0, 0, 3, 2),
(2, 0, 0, 0, 3) ))
assert M.det(method="bareis") == 275
assert M.det(method="det_lu") == 275
assert M.det(method="Bareis") == 275
M = Matrix(( (1, 0, 1, 2, 12),
(2, 0, 1, 1, 4),
(2, 1, 1, -1, 3),
(3, 2, -1, 1, 8),
(1, 1, 1, 0, 6) ))
assert M.det(method="bareis") == -55
assert M.det(method="det_lu") == -55
assert M.det(method="BAREISS") == -55
M = Matrix(( (-5, 2, 3, 4, 5),
( 1, -4, 3, 4, 5),
( 1, 2, -3, 4, 5),
( 1, 2, 3, -2, 5),
( 1, 2, 3, 4, -1) ))
assert M.det(method="bareis") == 11664
assert M.det(method="det_lu") == 11664
assert M.det(method="BERKOWITZ") == 11664
M = Matrix(( ( 2, 7, -1, 3, 2),
( 0, 0, 1, 0, 1),
(-2, 0, 7, 0, 2),
(-3, -2, 4, 5, 3),
( 1, 0, 0, 0, 1) ))
assert M.det(method="bareis") == 123
assert M.det(method="det_lu") == 123
assert M.det(method="LU") == 123
|
41d9b7f76e5f9e8eebb3996eb7399fa1354194b648ed7802d412c574d6fbec6d
|
from __future__ import print_function, division
from sympy import Basic, Expr, S, sympify
from .matexpr import ShapeError
class Determinant(Expr):
"""Matrix Determinant
Represents the determinant of a matrix expression.
Examples
========
>>> from sympy import MatrixSymbol, Determinant, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> Determinant(A)
Determinant(A)
>>> Determinant(eye(3)).doit()
1
"""
def __new__(cls, mat):
mat = sympify(mat)
if not mat.is_Matrix:
raise TypeError("Input to Determinant, %s, not a matrix" % str(mat))
if not mat.is_square:
raise ShapeError("Det of a non-square matrix")
return Basic.__new__(cls, mat)
@property
def arg(self):
return self.args[0]
def doit(self, expand=False):
try:
return self.arg._eval_determinant()
except (AttributeError, NotImplementedError):
return self
def det(matexpr):
""" Matrix Determinant
Examples
========
>>> from sympy import MatrixSymbol, det, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> det(A)
Determinant(A)
>>> det(eye(3))
1
"""
return Determinant(matexpr).doit()
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Determinant(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine, det
>>> X = MatrixSymbol('X', 2, 2)
>>> det(X)
Determinant(X)
>>> with assuming(Q.orthogonal(X)):
... print(refine(det(X)))
1
"""
if ask(Q.orthogonal(expr.arg), assumptions):
return S.One
elif ask(Q.singular(expr.arg), assumptions):
return S.Zero
elif ask(Q.unit_triangular(expr.arg), assumptions):
return S.One
return expr
handlers_dict['Determinant'] = refine_Determinant
|
cb23825ff483df8b22c25cec996d166381d95c7d00a60240dfa85f295470401c
|
from __future__ import print_function, division
from sympy.core.sympify import _sympify
from sympy.core import S, Basic
from sympy.matrices.expressions.matexpr import ShapeError
from sympy.matrices.expressions.matpow import MatPow
class Inverse(MatPow):
"""
The multiplicative inverse of a matrix expression
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the inverse, use the ``.inverse()``
method of matrices.
Examples
========
>>> from sympy import MatrixSymbol, Inverse
>>> A = MatrixSymbol('A', 3, 3)
>>> B = MatrixSymbol('B', 3, 3)
>>> Inverse(A)
A**(-1)
>>> A.inverse() == Inverse(A)
True
>>> (A*B).inverse()
B**(-1)*A**(-1)
>>> Inverse(A*B)
(A*B)**(-1)
"""
is_Inverse = True
exp = S(-1)
def __new__(cls, mat, exp=S(-1)):
# exp is there to make it consistent with
# inverse.func(*inverse.args) == inverse
mat = _sympify(mat)
if not mat.is_Matrix:
raise TypeError("mat should be a matrix")
if not mat.is_square:
raise ShapeError("Inverse of non-square matrix %s" % mat)
return Basic.__new__(cls, mat, exp)
@property
def arg(self):
return self.args[0]
@property
def shape(self):
return self.arg.shape
def _eval_inverse(self):
return self.arg
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import det
return 1/det(self.arg)
def doit(self, **hints):
if 'inv_expand' in hints and hints['inv_expand'] == False:
return self
if hints.get('deep', True):
return self.arg.doit(**hints).inverse()
else:
return self.arg.inverse()
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Inverse(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> X.I
X**(-1)
>>> with assuming(Q.orthogonal(X)):
... print(refine(X.I))
X.T
"""
if ask(Q.orthogonal(expr), assumptions):
return expr.arg.T
elif ask(Q.unitary(expr), assumptions):
return expr.arg.conjugate()
elif ask(Q.singular(expr), assumptions):
raise ValueError("Inverse of singular matrix %s" % expr.arg)
return expr
handlers_dict['Inverse'] = refine_Inverse
|
41620efb74bfc77c66d611b358b2fefe04a3bbc123630e29ad1d76b78c1ecf58
|
from __future__ import print_function, division
from sympy import Basic
from sympy.functions import adjoint, conjugate
from sympy.matrices.expressions.matexpr import MatrixExpr
class Transpose(MatrixExpr):
"""
The transpose of a matrix expression.
This is a symbolic object that simply stores its argument without
evaluating it. To actually compute the transpose, use the ``transpose()``
function, or the ``.T`` attribute of matrices.
Examples
========
>>> from sympy.matrices import MatrixSymbol, Transpose
>>> from sympy.functions import transpose
>>> A = MatrixSymbol('A', 3, 5)
>>> B = MatrixSymbol('B', 5, 3)
>>> Transpose(A)
A.T
>>> A.T == transpose(A) == Transpose(A)
True
>>> Transpose(A*B)
(A*B).T
>>> transpose(A*B)
B.T*A.T
"""
is_Transpose = True
def doit(self, **hints):
arg = self.arg
if hints.get('deep', True) and isinstance(arg, Basic):
arg = arg.doit(**hints)
try:
result = arg._eval_transpose()
return result if result is not None else Transpose(arg)
except AttributeError:
return Transpose(arg)
@property
def arg(self):
return self.args[0]
@property
def shape(self):
return self.arg.shape[::-1]
def _entry(self, i, j, expand=False):
return self.arg._entry(j, i, expand=expand)
def _eval_adjoint(self):
return conjugate(self.arg)
def _eval_conjugate(self):
return adjoint(self.arg)
def _eval_transpose(self):
return self.arg
def _eval_trace(self):
from .trace import Trace
return Trace(self.arg) # Trace(X.T) => Trace(X)
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import det
return det(self.arg)
def transpose(expr):
"""Matrix transpose"""
return Transpose(expr).doit(deep=False)
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_Transpose(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> X.T
X.T
>>> with assuming(Q.symmetric(X)):
... print(refine(X.T))
X
"""
if ask(Q.symmetric(expr), assumptions):
return expr.arg
return expr
handlers_dict['Transpose'] = refine_Transpose
|
76e8554cef78849ff1e48d8ba9f1ae83cde4d82996ca00ab1a8ce8e43672552f
|
from __future__ import print_function, division
from sympy import Number
from sympy.core import Mul, Basic, sympify, Add
from sympy.core.compatibility import range
from sympy.functions import adjoint
from sympy.matrices.expressions.transpose import transpose
from sympy.strategies import (rm_id, unpack, typed, flatten, exhaust,
do_one, new)
from sympy.matrices.expressions.matexpr import (MatrixExpr, ShapeError,
Identity, ZeroMatrix)
from sympy.matrices.expressions.matpow import MatPow
from sympy.matrices.matrices import MatrixBase
class MatMul(MatrixExpr, Mul):
"""
A product of matrix expressions
Examples
========
>>> from sympy import MatMul, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 4)
>>> B = MatrixSymbol('B', 4, 3)
>>> C = MatrixSymbol('C', 3, 6)
>>> MatMul(A, B, C)
A*B*C
"""
is_MatMul = True
def __new__(cls, *args, **kwargs):
check = kwargs.get('check', True)
args = list(map(sympify, args))
obj = Basic.__new__(cls, *args)
factor, matrices = obj.as_coeff_matrices()
if check:
validate(*matrices)
if not matrices:
return factor
return obj
@property
def shape(self):
matrices = [arg for arg in self.args if arg.is_Matrix]
return (matrices[0].rows, matrices[-1].cols)
def _entry(self, i, j, expand=True):
from sympy import Dummy, Sum, Mul, ImmutableMatrix, Integer
coeff, matrices = self.as_coeff_matrices()
if len(matrices) == 1: # situation like 2*X, matmul is just X
return coeff * matrices[0][i, j]
indices = [None]*(len(matrices) + 1)
ind_ranges = [None]*(len(matrices) - 1)
indices[0] = i
indices[-1] = j
for i in range(1, len(matrices)):
indices[i] = Dummy("i_%i" % i)
for i, arg in enumerate(matrices[:-1]):
ind_ranges[i] = arg.shape[1] - 1
matrices = [arg[indices[i], indices[i+1]] for i, arg in enumerate(matrices)]
expr_in_sum = Mul.fromiter(matrices)
if any(v.has(ImmutableMatrix) for v in matrices):
expand = True
result = coeff*Sum(
expr_in_sum,
*zip(indices[1:-1], [0]*len(ind_ranges), ind_ranges)
)
# Don't waste time in result.doit() if the sum bounds are symbolic
if not any(isinstance(v, (Integer, int)) for v in ind_ranges):
expand = False
return result.doit() if expand else result
def as_coeff_matrices(self):
scalars = [x for x in self.args if not x.is_Matrix]
matrices = [x for x in self.args if x.is_Matrix]
coeff = Mul(*scalars)
return coeff, matrices
def as_coeff_mmul(self):
coeff, matrices = self.as_coeff_matrices()
return coeff, MatMul(*matrices)
def _eval_transpose(self):
return MatMul(*[transpose(arg) for arg in self.args[::-1]]).doit()
def _eval_adjoint(self):
return MatMul(*[adjoint(arg) for arg in self.args[::-1]]).doit()
def _eval_trace(self):
factor, mmul = self.as_coeff_mmul()
if factor != 1:
from .trace import trace
return factor * trace(mmul.doit())
else:
raise NotImplementedError("Can't simplify any further")
def _eval_determinant(self):
from sympy.matrices.expressions.determinant import Determinant
factor, matrices = self.as_coeff_matrices()
square_matrices = only_squares(*matrices)
return factor**self.rows * Mul(*list(map(Determinant, square_matrices)))
def _eval_inverse(self):
try:
return MatMul(*[
arg.inverse() if isinstance(arg, MatrixExpr) else arg**-1
for arg in self.args[::-1]]).doit()
except ShapeError:
from sympy.matrices.expressions.inverse import Inverse
return Inverse(self)
def doit(self, **kwargs):
deep = kwargs.get('deep', True)
if deep:
args = [arg.doit(**kwargs) for arg in self.args]
else:
args = self.args
# treat scalar*MatrixSymbol or scalar*MatPow separately
mats = [arg for arg in self.args if arg.is_Matrix]
expr = canonicalize(MatMul(*args))
return expr
# Needed for partial compatibility with Mul
def args_cnc(self, **kwargs):
coeff, matrices = self.as_coeff_matrices()
# I don't know how coeff could have noncommutative factors, but this
# handles it.
coeff_c, coeff_nc = coeff.args_cnc(**kwargs)
return coeff_c, coeff_nc + matrices
def validate(*matrices):
""" Checks for valid shapes for args of MatMul """
for i in range(len(matrices)-1):
A, B = matrices[i:i+2]
if A.cols != B.rows:
raise ShapeError("Matrices %s and %s are not aligned"%(A, B))
# Rules
def newmul(*args):
if args[0] == 1:
args = args[1:]
return new(MatMul, *args)
def any_zeros(mul):
if any([arg.is_zero or (arg.is_Matrix and arg.is_ZeroMatrix)
for arg in mul.args]):
matrices = [arg for arg in mul.args if arg.is_Matrix]
return ZeroMatrix(matrices[0].rows, matrices[-1].cols)
return mul
def merge_explicit(matmul):
""" Merge explicit MatrixBase arguments
>>> from sympy import MatrixSymbol, eye, Matrix, MatMul, pprint
>>> from sympy.matrices.expressions.matmul import merge_explicit
>>> A = MatrixSymbol('A', 2, 2)
>>> B = Matrix([[1, 1], [1, 1]])
>>> C = Matrix([[1, 2], [3, 4]])
>>> X = MatMul(A, B, C)
>>> pprint(X)
[1 1] [1 2]
A*[ ]*[ ]
[1 1] [3 4]
>>> pprint(merge_explicit(X))
[4 6]
A*[ ]
[4 6]
>>> X = MatMul(B, A, C)
>>> pprint(X)
[1 1] [1 2]
[ ]*A*[ ]
[1 1] [3 4]
>>> pprint(merge_explicit(X))
[1 1] [1 2]
[ ]*A*[ ]
[1 1] [3 4]
"""
if not any(isinstance(arg, MatrixBase) for arg in matmul.args):
return matmul
newargs = []
last = matmul.args[0]
for arg in matmul.args[1:]:
if isinstance(arg, (MatrixBase, Number)) and isinstance(last, (MatrixBase, Number)):
last = last * arg
else:
newargs.append(last)
last = arg
newargs.append(last)
return MatMul(*newargs)
def xxinv(mul):
""" Y * X * X.I -> Y """
from sympy.matrices.expressions.inverse import Inverse
factor, matrices = mul.as_coeff_matrices()
for i, (X, Y) in enumerate(zip(matrices[:-1], matrices[1:])):
try:
if X.is_square and Y.is_square:
_X, x_exp = X, 1
_Y, y_exp = Y, 1
if isinstance(X, MatPow) and not isinstance(X, Inverse):
_X, x_exp = X.args
if isinstance(Y, MatPow) and not isinstance(Y, Inverse):
_Y, y_exp = Y.args
if _X == _Y.inverse():
if x_exp - y_exp > 0:
I = _X**(x_exp-y_exp)
else:
I = _Y**(y_exp-x_exp)
return newmul(factor, *(matrices[:i] + [I] + matrices[i+2:]))
except ValueError: # Y might not be invertible
pass
return mul
def remove_ids(mul):
""" Remove Identities from a MatMul
This is a modified version of sympy.strategies.rm_id.
This is necesssary because MatMul may contain both MatrixExprs and Exprs
as args.
See Also
========
sympy.strategies.rm_id
"""
# Separate Exprs from MatrixExprs in args
factor, mmul = mul.as_coeff_mmul()
# Apply standard rm_id for MatMuls
result = rm_id(lambda x: x.is_Identity is True)(mmul)
if result != mmul:
return newmul(factor, *result.args) # Recombine and return
else:
return mul
def factor_in_front(mul):
factor, matrices = mul.as_coeff_matrices()
if factor != 1:
return newmul(factor, *matrices)
return mul
def combine_powers(mul):
# combine consecutive powers with the same base into one
# e.g. A*A**2 -> A**3
from sympy.matrices.expressions import MatPow
factor, mmul = mul.as_coeff_mmul()
args = []
base = None
exp = 0
for arg in mmul.args:
if isinstance(arg, MatPow):
current_base = arg.args[0]
current_exp = arg.args[1]
else:
current_base = arg
current_exp = 1
if current_base == base:
exp += current_exp
else:
if not base is None:
if exp == 1:
args.append(base)
else:
args.append(base**exp)
exp = current_exp
base = current_base
if exp == 1:
args.append(base)
else:
args.append(base**exp)
return newmul(factor, *args)
rules = (any_zeros, remove_ids, xxinv, unpack, rm_id(lambda x: x == 1),
merge_explicit, factor_in_front, flatten, combine_powers)
canonicalize = exhaust(typed({MatMul: do_one(*rules)}))
def only_squares(*matrices):
"""factor matrices only if they are square"""
if matrices[0].rows != matrices[-1].cols:
raise RuntimeError("Invalid matrices being multiplied")
out = []
start = 0
for i, M in enumerate(matrices):
if M.cols == matrices[start].rows:
out.append(MatMul(*matrices[start:i+1]).doit())
start = i+1
return out
from sympy.assumptions.ask import ask, Q
from sympy.assumptions.refine import handlers_dict
def refine_MatMul(expr, assumptions):
"""
>>> from sympy import MatrixSymbol, Q, assuming, refine
>>> X = MatrixSymbol('X', 2, 2)
>>> expr = X * X.T
>>> print(expr)
X*X.T
>>> with assuming(Q.orthogonal(X)):
... print(refine(expr))
I
"""
newargs = []
exprargs = []
for args in expr.args:
if args.is_Matrix:
exprargs.append(args)
else:
newargs.append(args)
last = exprargs[0]
for arg in exprargs[1:]:
if arg == last.T and ask(Q.orthogonal(arg), assumptions):
last = Identity(arg.shape[0])
elif arg == last.conjugate() and ask(Q.unitary(arg), assumptions):
last = Identity(arg.shape[0])
else:
newargs.append(last)
last = arg
newargs.append(last)
return MatMul(*newargs)
handlers_dict['MatMul'] = refine_MatMul
|
fbdc962eb98789b0f21e1f1bb8e965b5b5e2f266fa6c76152084f98bd337e2d2
|
from __future__ import print_function, division
from .matexpr import MatrixExpr, ShapeError, Identity, ZeroMatrix
from .transpose import Transpose
from sympy.core.sympify import _sympify
from sympy.core.compatibility import range
from sympy.matrices import MatrixBase
from sympy.core import S, Basic
class MatPow(MatrixExpr):
def __new__(cls, base, exp):
base = _sympify(base)
if not base.is_Matrix:
raise TypeError("Function parameter should be a matrix")
exp = _sympify(exp)
return super(MatPow, cls).__new__(cls, base, exp)
@property
def base(self):
return self.args[0]
@property
def exp(self):
return self.args[1]
@property
def shape(self):
return self.base.shape
def _entry(self, i, j, **kwargs):
from sympy.matrices.expressions import MatMul
A = self.doit()
if isinstance(A, MatPow):
# We still have a MatPow, make an explicit MatMul out of it.
if not A.base.is_square:
raise ShapeError("Power of non-square matrix %s" % A.base)
elif A.exp.is_Integer and A.exp.is_positive:
A = MatMul(*[A.base for k in range(A.exp)])
#elif A.exp.is_Integer and self.exp.is_negative:
# Note: possible future improvement: in principle we can take
# positive powers of the inverse, but carefully avoid recursion,
# perhaps by adding `_entry` to Inverse (as it is our subclass).
# T = A.base.as_explicit().inverse()
# A = MatMul(*[T for k in range(-A.exp)])
else:
# Leave the expression unevaluated:
from sympy.matrices.expressions.matexpr import MatrixElement
return MatrixElement(self, i, j)
return A._entry(i, j)
def doit(self, **kwargs):
from sympy.matrices.expressions import Inverse
deep = kwargs.get('deep', True)
if deep:
args = [arg.doit(**kwargs) for arg in self.args]
else:
args = self.args
base, exp = args
# combine all powers, e.g. (A**2)**3 = A**6
while isinstance(base, MatPow):
exp = exp*base.args[1]
base = base.args[0]
if exp.is_zero and base.is_square:
if isinstance(base, MatrixBase):
return base.func(Identity(base.shape[0]))
return Identity(base.shape[0])
elif isinstance(base, ZeroMatrix) and exp.is_negative:
raise ValueError("Matrix determinant is 0, not invertible.")
elif isinstance(base, (Identity, ZeroMatrix)):
return base
elif isinstance(base, MatrixBase) and exp.is_number:
if exp is S.One:
return base
return base**exp
# Note: just evaluate cases we know, return unevaluated on others.
# E.g., MatrixSymbol('x', n, m) to power 0 is not an error.
elif exp is S(-1) and base.is_square:
return Inverse(base).doit(**kwargs)
elif exp is S.One:
return base
return MatPow(base, exp)
def _eval_transpose(self):
base, exp = self.args
return MatPow(base.T, exp)
|
ca69a2026c619eda46f9ce268e960e1cc6aa99037b0bd4e7d164f9d8d28a4715
|
from __future__ import print_function, division
from functools import wraps, reduce
import collections
from sympy.core import S, Symbol, Tuple, Integer, Basic, Expr, Eq
from sympy.core.decorators import call_highest_priority
from sympy.core.compatibility import range, SYMPY_INTS, default_sort_key
from sympy.core.sympify import SympifyError, sympify
from sympy.functions import conjugate, adjoint
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.matrices import ShapeError
from sympy.simplify import simplify
from sympy.utilities.misc import filldedent
def _sympifyit(arg, retval=None):
# This version of _sympifyit sympifies MutableMatrix objects
def deco(func):
@wraps(func)
def __sympifyit_wrapper(a, b):
try:
b = sympify(b, strict=True)
return func(a, b)
except SympifyError:
return retval
return __sympifyit_wrapper
return deco
class MatrixExpr(Expr):
"""Superclass for Matrix Expressions
MatrixExprs represent abstract matrices, linear transformations represented
within a particular basis.
Examples
========
>>> from sympy import MatrixSymbol
>>> A = MatrixSymbol('A', 3, 3)
>>> y = MatrixSymbol('y', 3, 1)
>>> x = (A.T*A).I * A * y
See Also
========
MatrixSymbol, MatAdd, MatMul, Transpose, Inverse
"""
# Should not be considered iterable by the
# sympy.core.compatibility.iterable function. Subclass that actually are
# iterable (i.e., explicit matrices) should set this to True.
_iterable = False
_op_priority = 11.0
is_Matrix = True
is_MatrixExpr = True
is_Identity = None
is_Inverse = False
is_Transpose = False
is_ZeroMatrix = False
is_MatAdd = False
is_MatMul = False
is_commutative = False
is_number = False
is_symbol = False
def __new__(cls, *args, **kwargs):
args = map(sympify, args)
return Basic.__new__(cls, *args, **kwargs)
# The following is adapted from the core Expr object
def __neg__(self):
return MatMul(S.NegativeOne, self).doit()
def __abs__(self):
raise NotImplementedError
@_sympifyit('other', NotImplemented)
@call_highest_priority('__radd__')
def __add__(self, other):
return MatAdd(self, other, check=True).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__add__')
def __radd__(self, other):
return MatAdd(other, self, check=True).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rsub__')
def __sub__(self, other):
return MatAdd(self, -other, check=True).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__sub__')
def __rsub__(self, other):
return MatAdd(other, -self, check=True).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmul__')
def __mul__(self, other):
return MatMul(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmul__')
def __matmul__(self, other):
return MatMul(self, other).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return MatMul(other, self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mul__')
def __rmatmul__(self, other):
return MatMul(other, self).doit()
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rpow__')
def __pow__(self, other):
if not self.is_square:
raise ShapeError("Power of non-square matrix %s" % self)
elif self.is_Identity:
return self
elif other is S.Zero:
return Identity(self.rows)
elif other is S.One:
return self
return MatPow(self, other).doit(deep=False)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__pow__')
def __rpow__(self, other):
raise NotImplementedError("Matrix Power not defined")
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rdiv__')
def __div__(self, other):
return self * other**S.NegativeOne
@_sympifyit('other', NotImplemented)
@call_highest_priority('__div__')
def __rdiv__(self, other):
raise NotImplementedError()
#return MatMul(other, Pow(self, S.NegativeOne))
__truediv__ = __div__
__rtruediv__ = __rdiv__
@property
def rows(self):
return self.shape[0]
@property
def cols(self):
return self.shape[1]
@property
def is_square(self):
return self.rows == self.cols
def _eval_conjugate(self):
from sympy.matrices.expressions.adjoint import Adjoint
from sympy.matrices.expressions.transpose import Transpose
return Adjoint(Transpose(self))
def as_real_imag(self):
from sympy import I
real = (S(1)/2) * (self + self._eval_conjugate())
im = (self - self._eval_conjugate())/(2*I)
return (real, im)
def _eval_inverse(self):
from sympy.matrices.expressions.inverse import Inverse
return Inverse(self)
def _eval_transpose(self):
return Transpose(self)
def _eval_power(self, exp):
return MatPow(self, exp)
def _eval_simplify(self, **kwargs):
if self.is_Atom:
return self
else:
return self.__class__(*[simplify(x, **kwargs) for x in self.args])
def _eval_adjoint(self):
from sympy.matrices.expressions.adjoint import Adjoint
return Adjoint(self)
def _eval_derivative(self, v):
if not isinstance(v, MatrixExpr):
return None
# Convert to the index-summation notation, perform the derivative, then
# reconvert it back to matrix expression.
from sympy import symbols, Dummy, Lambda, Trace
i, j, m, n = symbols("i j m n", cls=Dummy)
M = self._entry(i, j, expand=False)
# Replace traces with summations:
def getsum(x):
di = Dummy("d_i")
return Sum(x.args[0], (di, 0, x.args[0].shape[0]-1))
M = M.replace(lambda x: isinstance(x, Trace), getsum)
repl = {}
if self.shape[0] == 1:
repl[i] = 0
if self.shape[1] == 1:
repl[j] = 0
if v.shape[0] == 1:
repl[m] = 0
if v.shape[1] == 1:
repl[n] = 0
res = M.diff(v[m, n])
res = res.xreplace(repl)
if res == 0:
return res
if len(repl) < 2:
parsed = res
else:
if m not in repl:
parsed = MatrixExpr.from_index_summation(res, m)
elif i not in repl:
parsed = MatrixExpr.from_index_summation(res, i)
else:
parsed = MatrixExpr.from_index_summation(res)
if (parsed.has(m)) or (parsed.has(n)) or (parsed.has(i)) or (parsed.has(j)):
# In this case, there are still some KroneckerDelta.
# It's because the result is not a matrix, but a higher dimensional array.
return None
else:
return parsed
def _eval_derivative_n_times(self, x, n):
return Basic._eval_derivative_n_times(self, x, n)
def _entry(self, i, j, **kwargs):
raise NotImplementedError(
"Indexing not implemented for %s" % self.__class__.__name__)
def adjoint(self):
return adjoint(self)
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product. """
return S.One, self
def conjugate(self):
return conjugate(self)
def transpose(self):
from sympy.matrices.expressions.transpose import transpose
return transpose(self)
T = property(transpose, None, None, 'Matrix transposition.')
def inverse(self):
return self._eval_inverse()
inv = inverse
@property
def I(self):
return self.inverse()
def valid_index(self, i, j):
def is_valid(idx):
return isinstance(idx, (int, Integer, Symbol, Expr))
return (is_valid(i) and is_valid(j) and
(self.rows is None or
(0 <= i) != False and (i < self.rows) != False) and
(0 <= j) != False and (j < self.cols) != False)
def __getitem__(self, key):
if not isinstance(key, tuple) and isinstance(key, slice):
from sympy.matrices.expressions.slice import MatrixSlice
return MatrixSlice(self, key, (0, None, 1))
if isinstance(key, tuple) and len(key) == 2:
i, j = key
if isinstance(i, slice) or isinstance(j, slice):
from sympy.matrices.expressions.slice import MatrixSlice
return MatrixSlice(self, i, j)
i, j = sympify(i), sympify(j)
if self.valid_index(i, j) != False:
return self._entry(i, j)
else:
raise IndexError("Invalid indices (%s, %s)" % (i, j))
elif isinstance(key, (SYMPY_INTS, Integer)):
# row-wise decomposition of matrix
rows, cols = self.shape
# allow single indexing if number of columns is known
if not isinstance(cols, Integer):
raise IndexError(filldedent('''
Single indexing is only supported when the number
of columns is known.'''))
key = sympify(key)
i = key // cols
j = key % cols
if self.valid_index(i, j) != False:
return self._entry(i, j)
else:
raise IndexError("Invalid index %s" % key)
elif isinstance(key, (Symbol, Expr)):
raise IndexError(filldedent('''
Only integers may be used when addressing the matrix
with a single index.'''))
raise IndexError("Invalid index, wanted %s[i,j]" % self)
def as_explicit(self):
"""
Returns a dense Matrix with elements represented explicitly
Returns an object of type ImmutableDenseMatrix.
Examples
========
>>> from sympy import Identity
>>> I = Identity(3)
>>> I
I
>>> I.as_explicit()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
as_mutable: returns mutable Matrix type
"""
from sympy.matrices.immutable import ImmutableDenseMatrix
return ImmutableDenseMatrix([[ self[i, j]
for j in range(self.cols)]
for i in range(self.rows)])
def as_mutable(self):
"""
Returns a dense, mutable matrix with elements represented explicitly
Examples
========
>>> from sympy import Identity
>>> I = Identity(3)
>>> I
I
>>> I.shape
(3, 3)
>>> I.as_mutable()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
as_explicit: returns ImmutableDenseMatrix
"""
return self.as_explicit().as_mutable()
def __array__(self):
from numpy import empty
a = empty(self.shape, dtype=object)
for i in range(self.rows):
for j in range(self.cols):
a[i, j] = self[i, j]
return a
def equals(self, other):
"""
Test elementwise equality between matrices, potentially of different
types
>>> from sympy import Identity, eye
>>> Identity(3).equals(eye(3))
True
"""
return self.as_explicit().equals(other)
def canonicalize(self):
return self
def as_coeff_mmul(self):
return 1, MatMul(self)
@staticmethod
def from_index_summation(expr, first_index=None, last_index=None, dimensions=None):
r"""
Parse expression of matrices with explicitly summed indices into a
matrix expression without indices, if possible.
This transformation expressed in mathematical notation:
`\sum_{j=0}^{N-1} A_{i,j} B_{j,k} \Longrightarrow \mathbf{A}\cdot \mathbf{B}`
Optional parameter ``first_index``: specify which free index to use as
the index starting the expression.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum, Symbol
>>> from sympy.abc import i, j, k, l, N
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> expr = Sum(A[i, j]*B[j, k], (j, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A*B
Transposition is detected:
>>> expr = Sum(A[j, i]*B[j, k], (j, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A.T*B
Detect the trace:
>>> expr = Sum(A[i, i], (i, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
Trace(A)
More complicated expressions:
>>> expr = Sum(A[i, j]*B[k, j]*A[l, k], (j, 0, N-1), (k, 0, N-1))
>>> MatrixExpr.from_index_summation(expr)
A*B.T*A.T
"""
from sympy import Sum, Mul, Add, MatMul, transpose, trace
from sympy.strategies.traverse import bottom_up
def remove_matelement(expr, i1, i2):
def repl_match(pos):
def func(x):
if not isinstance(x, MatrixElement):
return False
if x.args[pos] != i1:
return False
if x.args[3-pos] == 0:
if x.args[0].shape[2-pos] == 1:
return True
else:
return False
return True
return func
expr = expr.replace(repl_match(1),
lambda x: x.args[0])
expr = expr.replace(repl_match(2),
lambda x: transpose(x.args[0]))
# Make sure that all Mul are transformed to MatMul and that they
# are flattened:
rule = bottom_up(lambda x: reduce(lambda a, b: a*b, x.args) if isinstance(x, (Mul, MatMul)) else x)
return rule(expr)
def recurse_expr(expr, index_ranges={}):
if expr.is_Mul:
nonmatargs = []
pos_arg = []
pos_ind = []
dlinks = {}
link_ind = []
counter = 0
args_ind = []
for arg in expr.args:
retvals = recurse_expr(arg, index_ranges)
assert isinstance(retvals, list)
if isinstance(retvals, list):
for i in retvals:
args_ind.append(i)
else:
args_ind.append(retvals)
for arg_symbol, arg_indices in args_ind:
if arg_indices is None:
nonmatargs.append(arg_symbol)
continue
if isinstance(arg_symbol, MatrixElement):
arg_symbol = arg_symbol.args[0]
pos_arg.append(arg_symbol)
pos_ind.append(arg_indices)
link_ind.append([None]*len(arg_indices))
for i, ind in enumerate(arg_indices):
if ind in dlinks:
other_i = dlinks[ind]
link_ind[counter][i] = other_i
link_ind[other_i[0]][other_i[1]] = (counter, i)
dlinks[ind] = (counter, i)
counter += 1
counter2 = 0
lines = {}
while counter2 < len(link_ind):
for i, e in enumerate(link_ind):
if None in e:
line_start_index = (i, e.index(None))
break
cur_ind_pos = line_start_index
cur_line = []
index1 = pos_ind[cur_ind_pos[0]][cur_ind_pos[1]]
while True:
d, r = cur_ind_pos
if pos_arg[d] != 1:
if r % 2 == 1:
cur_line.append(transpose(pos_arg[d]))
else:
cur_line.append(pos_arg[d])
next_ind_pos = link_ind[d][1-r]
counter2 += 1
# Mark as visited, there will be no `None` anymore:
link_ind[d] = (-1, -1)
if next_ind_pos is None:
index2 = pos_ind[d][1-r]
lines[(index1, index2)] = cur_line
break
cur_ind_pos = next_ind_pos
ret_indices = list(j for i in lines for j in i)
lines = {k: MatMul.fromiter(v) if len(v) != 1 else v[0] for k, v in lines.items()}
return [(Mul.fromiter(nonmatargs), None)] + [
(MatrixElement(a, i, j), (i, j)) for (i, j), a in lines.items()
]
elif expr.is_Add:
res = [recurse_expr(i) for i in expr.args]
d = collections.defaultdict(list)
for res_addend in res:
scalar = 1
for elem, indices in res_addend:
if indices is None:
scalar = elem
continue
indices = tuple(sorted(indices, key=default_sort_key))
d[indices].append(scalar*remove_matelement(elem, *indices))
scalar = 1
return [(MatrixElement(Add.fromiter(v), *k), k) for k, v in d.items()]
elif isinstance(expr, KroneckerDelta):
i1, i2 = expr.args
if dimensions is not None:
identity = Identity(dimensions[0])
else:
identity = S.One
return [(MatrixElement(identity, i1, i2), (i1, i2))]
elif isinstance(expr, MatrixElement):
matrix_symbol, i1, i2 = expr.args
if i1 in index_ranges:
r1, r2 = index_ranges[i1]
if r1 != 0 or matrix_symbol.shape[0] != r2+1:
raise ValueError("index range mismatch: {0} vs. (0, {1})".format(
(r1, r2), matrix_symbol.shape[0]))
if i2 in index_ranges:
r1, r2 = index_ranges[i2]
if r1 != 0 or matrix_symbol.shape[1] != r2+1:
raise ValueError("index range mismatch: {0} vs. (0, {1})".format(
(r1, r2), matrix_symbol.shape[1]))
if (i1 == i2) and (i1 in index_ranges):
return [(trace(matrix_symbol), None)]
return [(MatrixElement(matrix_symbol, i1, i2), (i1, i2))]
elif isinstance(expr, Sum):
return recurse_expr(
expr.args[0],
index_ranges={i[0]: i[1:] for i in expr.args[1:]}
)
else:
return [(expr, None)]
retvals = recurse_expr(expr)
factors, indices = zip(*retvals)
retexpr = Mul.fromiter(factors)
if len(indices) == 0 or list(set(indices)) == [None]:
return retexpr
if first_index is None:
for i in indices:
if i is not None:
ind0 = i
break
return remove_matelement(retexpr, *ind0)
else:
return remove_matelement(retexpr, first_index, last_index)
class MatrixElement(Expr):
parent = property(lambda self: self.args[0])
i = property(lambda self: self.args[1])
j = property(lambda self: self.args[2])
_diff_wrt = True
is_symbol = True
is_commutative = True
def __new__(cls, name, n, m):
n, m = map(sympify, (n, m))
from sympy import MatrixBase
if isinstance(name, (MatrixBase,)):
if n.is_Integer and m.is_Integer:
return name[n, m]
name = sympify(name)
obj = Expr.__new__(cls, name, n, m)
return obj
def doit(self, **kwargs):
deep = kwargs.get('deep', True)
if deep:
args = [arg.doit(**kwargs) for arg in self.args]
else:
args = self.args
return args[0][args[1], args[2]]
@property
def indices(self):
return self.args[1:]
def _eval_derivative(self, v):
from sympy import Sum, symbols, Dummy
if not isinstance(v, MatrixElement):
from sympy import MatrixBase
if isinstance(self.parent, MatrixBase):
return self.parent.diff(v)[self.i, self.j]
return S.Zero
M = self.args[0]
if M == v.args[0]:
return KroneckerDelta(self.args[1], v.args[1])*KroneckerDelta(self.args[2], v.args[2])
if isinstance(M, Inverse):
i, j = self.args[1:]
i1, i2 = symbols("z1, z2", cls=Dummy)
Y = M.args[0]
r1, r2 = Y.shape
return -Sum(M[i, i1]*Y[i1, i2].diff(v)*M[i2, j], (i1, 0, r1-1), (i2, 0, r2-1))
if self.has(v.args[0]):
return None
return S.Zero
class MatrixSymbol(MatrixExpr):
"""Symbolic representation of a Matrix object
Creates a SymPy Symbol to represent a Matrix. This matrix has a shape and
can be included in Matrix Expressions
Examples
========
>>> from sympy import MatrixSymbol, Identity
>>> A = MatrixSymbol('A', 3, 4) # A 3 by 4 Matrix
>>> B = MatrixSymbol('B', 4, 3) # A 4 by 3 Matrix
>>> A.shape
(3, 4)
>>> 2*A*B + Identity(3)
I + 2*A*B
"""
is_commutative = False
is_symbol = True
_diff_wrt = True
def __new__(cls, name, n, m):
n, m = sympify(n), sympify(m)
obj = Basic.__new__(cls, name, n, m)
return obj
def _hashable_content(self):
return (self.name, self.shape)
@property
def shape(self):
return self.args[1:3]
@property
def name(self):
return self.args[0]
def _eval_subs(self, old, new):
# only do substitutions in shape
shape = Tuple(*self.shape)._subs(old, new)
return MatrixSymbol(self.name, *shape)
def __call__(self, *args):
raise TypeError("%s object is not callable" % self.__class__)
def _entry(self, i, j, **kwargs):
return MatrixElement(self, i, j)
@property
def free_symbols(self):
return set((self,))
def doit(self, **hints):
if hints.get('deep', True):
return type(self)(self.name, self.args[1].doit(**hints),
self.args[2].doit(**hints))
else:
return self
def _eval_simplify(self, **kwargs):
return self
class Identity(MatrixExpr):
"""The Matrix Identity I - multiplicative identity
Examples
========
>>> from sympy.matrices import Identity, MatrixSymbol
>>> A = MatrixSymbol('A', 3, 5)
>>> I = Identity(3)
>>> I*A
A
"""
is_Identity = True
def __new__(cls, n):
return super(Identity, cls).__new__(cls, sympify(n))
@property
def rows(self):
return self.args[0]
@property
def cols(self):
return self.args[0]
@property
def shape(self):
return (self.args[0], self.args[0])
def _eval_transpose(self):
return self
def _eval_trace(self):
return self.rows
def _eval_inverse(self):
return self
def conjugate(self):
return self
def _entry(self, i, j, **kwargs):
eq = Eq(i, j)
if eq is S.true:
return S.One
elif eq is S.false:
return S.Zero
return KroneckerDelta(i, j)
def _eval_determinant(self):
return S.One
class ZeroMatrix(MatrixExpr):
"""The Matrix Zero 0 - additive identity
Examples
========
>>> from sympy import MatrixSymbol, ZeroMatrix
>>> A = MatrixSymbol('A', 3, 5)
>>> Z = ZeroMatrix(3, 5)
>>> A + Z
A
>>> Z*A.T
0
"""
is_ZeroMatrix = True
def __new__(cls, m, n):
return super(ZeroMatrix, cls).__new__(cls, m, n)
@property
def shape(self):
return (self.args[0], self.args[1])
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rpow__')
def __pow__(self, other):
if other != 1 and not self.is_square:
raise ShapeError("Power of non-square matrix %s" % self)
if other == 0:
return Identity(self.rows)
if other < 1:
raise ValueError("Matrix det == 0; not invertible.")
return self
def _eval_transpose(self):
return ZeroMatrix(self.cols, self.rows)
def _eval_trace(self):
return S.Zero
def _eval_determinant(self):
return S.Zero
def conjugate(self):
return self
def _entry(self, i, j, **kwargs):
return S.Zero
def __nonzero__(self):
return False
__bool__ = __nonzero__
def matrix_symbols(expr):
return [sym for sym in expr.free_symbols if sym.is_Matrix]
from .matmul import MatMul
from .matadd import MatAdd
from .matpow import MatPow
from .transpose import Transpose
from .inverse import Inverse
|
49f9207695b76ed58974400621328afb8fe72b04b069f6405a8e0deb5dcdc40f
|
from __future__ import print_function, division
from sympy import Basic, Expr, sympify
from sympy.matrices.matrices import MatrixBase
from .matexpr import ShapeError
class Trace(Expr):
"""Matrix Trace
Represents the trace of a matrix expression.
Examples
========
>>> from sympy import MatrixSymbol, Trace, eye
>>> A = MatrixSymbol('A', 3, 3)
>>> Trace(A)
Trace(A)
"""
is_Trace = True
def __new__(cls, mat):
mat = sympify(mat)
if not mat.is_Matrix:
raise TypeError("input to Trace, %s, is not a matrix" % str(mat))
if not mat.is_square:
raise ShapeError("Trace of a non-square matrix")
return Basic.__new__(cls, mat)
def _eval_transpose(self):
return self
def _eval_derivative(self, v):
from sympy import Dummy, MatrixExpr, Sum
if not isinstance(v, MatrixExpr):
return None
t1 = Dummy("t_1")
m = Dummy("m")
n = Dummy("n")
# TODO: use self.rewrite(Sum) instead:
return MatrixExpr.from_index_summation(
Sum(self.args[0][t1, t1].diff(v[m, n]), (t1, 0, self.args[0].shape[0]-1)),
m,
dimensions=(v.args[1:])
)
@property
def arg(self):
return self.args[0]
def doit(self, **kwargs):
if kwargs.get('deep', True):
arg = self.arg.doit(**kwargs)
try:
return arg._eval_trace()
except (AttributeError, NotImplementedError):
return Trace(arg)
else:
# _eval_trace would go too deep here
if isinstance(self.arg, MatrixBase):
return trace(self.arg)
else:
return Trace(self.arg)
def _eval_rewrite_as_Sum(self, expr, **kwargs):
from sympy import Sum, Dummy
i = Dummy('i')
return Sum(self.arg[i, i], (i, 0, self.arg.rows-1)).doit()
def trace(expr):
"""Trace of a Matrix. Sum of the diagonal elements.
Examples
========
>>> from sympy import trace, Symbol, MatrixSymbol, pprint, eye
>>> n = Symbol('n')
>>> X = MatrixSymbol('X', n, n) # A square matrix
>>> trace(2*X)
2*Trace(X)
>>> trace(eye(3))
3
"""
return Trace(expr).doit()
|
f3a47d13f1ebd70b188b5fe1f5a84d4884e9d5865d05b1188f8d2212e5930a33
|
from __future__ import print_function, division
from sympy import ask, Q
from sympy.core import Basic, Add, sympify
from sympy.core.compatibility import range
from sympy.strategies import typed, exhaust, condition, do_one, unpack
from sympy.strategies.traverse import bottom_up
from sympy.utilities import sift
from sympy.matrices.expressions.matexpr import MatrixExpr, ZeroMatrix, Identity
from sympy.matrices.expressions.matmul import MatMul
from sympy.matrices.expressions.matadd import MatAdd
from sympy.matrices.expressions.matpow import MatPow
from sympy.matrices.expressions.transpose import Transpose, transpose
from sympy.matrices.expressions.trace import Trace
from sympy.matrices.expressions.determinant import det, Determinant
from sympy.matrices.expressions.slice import MatrixSlice
from sympy.matrices.expressions.inverse import Inverse
from sympy.matrices import Matrix, ShapeError
from sympy.functions.elementary.complexes import re, im
class BlockMatrix(MatrixExpr):
"""A BlockMatrix is a Matrix composed of other smaller, submatrices
The submatrices are stored in a SymPy Matrix object but accessed as part of
a Matrix Expression
>>> from sympy import (MatrixSymbol, BlockMatrix, symbols,
... Identity, ZeroMatrix, block_collapse)
>>> n,m,l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m ,m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m,n), Y]])
>>> print(B)
Matrix([
[X, Z],
[0, Y]])
>>> C = BlockMatrix([[Identity(n), Z]])
>>> print(C)
Matrix([[I, Z]])
>>> print(block_collapse(C*B))
Matrix([[X, Z + Z*Y]])
"""
def __new__(cls, *args):
from sympy.matrices.immutable import ImmutableDenseMatrix
args = map(sympify, args)
mat = ImmutableDenseMatrix(*args)
obj = Basic.__new__(cls, mat)
return obj
@property
def shape(self):
numrows = numcols = 0
M = self.blocks
for i in range(M.shape[0]):
numrows += M[i, 0].shape[0]
for i in range(M.shape[1]):
numcols += M[0, i].shape[1]
return (numrows, numcols)
@property
def blockshape(self):
return self.blocks.shape
@property
def blocks(self):
return self.args[0]
@property
def rowblocksizes(self):
return [self.blocks[i, 0].rows for i in range(self.blockshape[0])]
@property
def colblocksizes(self):
return [self.blocks[0, i].cols for i in range(self.blockshape[1])]
def structurally_equal(self, other):
return (isinstance(other, BlockMatrix)
and self.shape == other.shape
and self.blockshape == other.blockshape
and self.rowblocksizes == other.rowblocksizes
and self.colblocksizes == other.colblocksizes)
def _blockmul(self, other):
if (isinstance(other, BlockMatrix) and
self.colblocksizes == other.rowblocksizes):
return BlockMatrix(self.blocks*other.blocks)
return self * other
def _blockadd(self, other):
if (isinstance(other, BlockMatrix)
and self.structurally_equal(other)):
return BlockMatrix(self.blocks + other.blocks)
return self + other
def _eval_transpose(self):
# Flip all the individual matrices
matrices = [transpose(matrix) for matrix in self.blocks]
# Make a copy
M = Matrix(self.blockshape[0], self.blockshape[1], matrices)
# Transpose the block structure
M = M.transpose()
return BlockMatrix(M)
def _eval_trace(self):
if self.rowblocksizes == self.colblocksizes:
return Add(*[Trace(self.blocks[i, i])
for i in range(self.blockshape[0])])
raise NotImplementedError(
"Can't perform trace of irregular blockshape")
def _eval_determinant(self):
if self.blockshape == (2, 2):
[[A, B],
[C, D]] = self.blocks.tolist()
if ask(Q.invertible(A)):
return det(A)*det(D - C*A.I*B)
elif ask(Q.invertible(D)):
return det(D)*det(A - B*D.I*C)
return Determinant(self)
def as_real_imag(self):
real_matrices = [re(matrix) for matrix in self.blocks]
real_matrices = Matrix(self.blockshape[0], self.blockshape[1], real_matrices)
im_matrices = [im(matrix) for matrix in self.blocks]
im_matrices = Matrix(self.blockshape[0], self.blockshape[1], im_matrices)
return (real_matrices, im_matrices)
def transpose(self):
"""Return transpose of matrix.
Examples
========
>>> from sympy import MatrixSymbol, BlockMatrix, ZeroMatrix
>>> from sympy.abc import l, m, n
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m ,m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m,n), Y]])
>>> B.transpose()
Matrix([
[X.T, 0],
[Z.T, Y.T]])
>>> _.transpose()
Matrix([
[X, Z],
[0, Y]])
"""
return self._eval_transpose()
def _entry(self, i, j):
# Find row entry
for row_block, numrows in enumerate(self.rowblocksizes):
if (i < numrows) != False:
break
else:
i -= numrows
for col_block, numcols in enumerate(self.colblocksizes):
if (j < numcols) != False:
break
else:
j -= numcols
return self.blocks[row_block, col_block][i, j]
@property
def is_Identity(self):
if self.blockshape[0] != self.blockshape[1]:
return False
for i in range(self.blockshape[0]):
for j in range(self.blockshape[1]):
if i==j and not self.blocks[i, j].is_Identity:
return False
if i!=j and not self.blocks[i, j].is_ZeroMatrix:
return False
return True
@property
def is_structurally_symmetric(self):
return self.rowblocksizes == self.colblocksizes
def equals(self, other):
if self == other:
return True
if (isinstance(other, BlockMatrix) and self.blocks == other.blocks):
return True
return super(BlockMatrix, self).equals(other)
class BlockDiagMatrix(BlockMatrix):
"""
A BlockDiagMatrix is a BlockMatrix with matrices only along the diagonal
>>> from sympy import MatrixSymbol, BlockDiagMatrix, symbols, Identity
>>> n,m,l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m ,m)
>>> BlockDiagMatrix(X, Y)
Matrix([
[X, 0],
[0, Y]])
"""
def __new__(cls, *mats):
return Basic.__new__(BlockDiagMatrix, *mats)
@property
def diag(self):
return self.args
@property
def blocks(self):
from sympy.matrices.immutable import ImmutableDenseMatrix
mats = self.args
data = [[mats[i] if i == j else ZeroMatrix(mats[i].rows, mats[j].cols)
for j in range(len(mats))]
for i in range(len(mats))]
return ImmutableDenseMatrix(data)
@property
def shape(self):
return (sum(block.rows for block in self.args),
sum(block.cols for block in self.args))
@property
def blockshape(self):
n = len(self.args)
return (n, n)
@property
def rowblocksizes(self):
return [block.rows for block in self.args]
@property
def colblocksizes(self):
return [block.cols for block in self.args]
def _eval_inverse(self, expand='ignored'):
return BlockDiagMatrix(*[mat.inverse() for mat in self.args])
def _blockmul(self, other):
if (isinstance(other, BlockDiagMatrix) and
self.colblocksizes == other.rowblocksizes):
return BlockDiagMatrix(*[a*b for a, b in zip(self.args, other.args)])
else:
return BlockMatrix._blockmul(self, other)
def _blockadd(self, other):
if (isinstance(other, BlockDiagMatrix) and
self.blockshape == other.blockshape and
self.rowblocksizes == other.rowblocksizes and
self.colblocksizes == other.colblocksizes):
return BlockDiagMatrix(*[a + b for a, b in zip(self.args, other.args)])
else:
return BlockMatrix._blockadd(self, other)
def block_collapse(expr):
"""Evaluates a block matrix expression
>>> from sympy import MatrixSymbol, BlockMatrix, symbols, \
Identity, Matrix, ZeroMatrix, block_collapse
>>> n,m,l = symbols('n m l')
>>> X = MatrixSymbol('X', n, n)
>>> Y = MatrixSymbol('Y', m ,m)
>>> Z = MatrixSymbol('Z', n, m)
>>> B = BlockMatrix([[X, Z], [ZeroMatrix(m, n), Y]])
>>> print(B)
Matrix([
[X, Z],
[0, Y]])
>>> C = BlockMatrix([[Identity(n), Z]])
>>> print(C)
Matrix([[I, Z]])
>>> print(block_collapse(C*B))
Matrix([[X, Z + Z*Y]])
"""
hasbm = lambda expr: isinstance(expr, MatrixExpr) and expr.has(BlockMatrix)
rule = exhaust(
bottom_up(exhaust(condition(hasbm, typed(
{MatAdd: do_one(bc_matadd, bc_block_plus_ident),
MatMul: do_one(bc_matmul, bc_dist),
MatPow: bc_matmul,
Transpose: bc_transpose,
Inverse: bc_inverse,
BlockMatrix: do_one(bc_unpack, deblock)})))))
result = rule(expr)
try:
return result.doit()
except AttributeError:
return result
def bc_unpack(expr):
if expr.blockshape == (1, 1):
return expr.blocks[0, 0]
return expr
def bc_matadd(expr):
args = sift(expr.args, lambda M: isinstance(M, BlockMatrix))
blocks = args[True]
if not blocks:
return expr
nonblocks = args[False]
block = blocks[0]
for b in blocks[1:]:
block = block._blockadd(b)
if nonblocks:
return MatAdd(*nonblocks) + block
else:
return block
def bc_block_plus_ident(expr):
idents = [arg for arg in expr.args if arg.is_Identity]
if not idents:
return expr
blocks = [arg for arg in expr.args if isinstance(arg, BlockMatrix)]
if (blocks and all(b.structurally_equal(blocks[0]) for b in blocks)
and blocks[0].is_structurally_symmetric):
block_id = BlockDiagMatrix(*[Identity(k)
for k in blocks[0].rowblocksizes])
return MatAdd(block_id * len(idents), *blocks).doit()
return expr
def bc_dist(expr):
""" Turn a*[X, Y] into [a*X, a*Y] """
factor, mat = expr.as_coeff_mmul()
if factor != 1 and isinstance(unpack(mat), BlockMatrix):
B = unpack(mat).blocks
return BlockMatrix([[factor * B[i, j] for j in range(B.cols)]
for i in range(B.rows)])
return expr
def bc_matmul(expr):
if isinstance(expr, MatPow):
if expr.args[1].is_Integer:
factor, matrices = (1, [expr.args[0]]*expr.args[1])
else:
return expr
else:
factor, matrices = expr.as_coeff_matrices()
i = 0
while (i+1 < len(matrices)):
A, B = matrices[i:i+2]
if isinstance(A, BlockMatrix) and isinstance(B, BlockMatrix):
matrices[i] = A._blockmul(B)
matrices.pop(i+1)
elif isinstance(A, BlockMatrix):
matrices[i] = A._blockmul(BlockMatrix([[B]]))
matrices.pop(i+1)
elif isinstance(B, BlockMatrix):
matrices[i] = BlockMatrix([[A]])._blockmul(B)
matrices.pop(i+1)
else:
i+=1
return MatMul(factor, *matrices).doit()
def bc_transpose(expr):
return BlockMatrix(block_collapse(expr.arg).blocks.applyfunc(transpose).T)
def bc_inverse(expr):
expr2 = blockinverse_1x1(expr)
if expr != expr2:
return expr2
return blockinverse_2x2(Inverse(reblock_2x2(expr.arg)))
def blockinverse_1x1(expr):
if isinstance(expr.arg, BlockMatrix) and expr.arg.blockshape == (1, 1):
mat = Matrix([[expr.arg.blocks[0].inverse()]])
return BlockMatrix(mat)
return expr
def blockinverse_2x2(expr):
if isinstance(expr.arg, BlockMatrix) and expr.arg.blockshape == (2, 2):
# Cite: The Matrix Cookbook Section 9.1.3
[[A, B],
[C, D]] = expr.arg.blocks.tolist()
return BlockMatrix([[ (A - B*D.I*C).I, (-A).I*B*(D - C*A.I*B).I],
[-(D - C*A.I*B).I*C*A.I, (D - C*A.I*B).I]])
else:
return expr
def deblock(B):
""" Flatten a BlockMatrix of BlockMatrices """
if not isinstance(B, BlockMatrix) or not B.blocks.has(BlockMatrix):
return B
wrap = lambda x: x if isinstance(x, BlockMatrix) else BlockMatrix([[x]])
bb = B.blocks.applyfunc(wrap) # everything is a block
from sympy import Matrix
try:
MM = Matrix(0, sum(bb[0, i].blocks.shape[1] for i in range(bb.shape[1])), [])
for row in range(0, bb.shape[0]):
M = Matrix(bb[row, 0].blocks)
for col in range(1, bb.shape[1]):
M = M.row_join(bb[row, col].blocks)
MM = MM.col_join(M)
return BlockMatrix(MM)
except ShapeError:
return B
def reblock_2x2(B):
""" Reblock a BlockMatrix so that it has 2x2 blocks of block matrices """
if not isinstance(B, BlockMatrix) or not all(d > 2 for d in B.blocks.shape):
return B
BM = BlockMatrix # for brevity's sake
return BM([[ B.blocks[0, 0], BM(B.blocks[0, 1:])],
[BM(B.blocks[1:, 0]), BM(B.blocks[1:, 1:])]])
def bounds(sizes):
""" Convert sequence of numbers into pairs of low-high pairs
>>> from sympy.matrices.expressions.blockmatrix import bounds
>>> bounds((1, 10, 50))
[(0, 1), (1, 11), (11, 61)]
"""
low = 0
rv = []
for size in sizes:
rv.append((low, low + size))
low += size
return rv
def blockcut(expr, rowsizes, colsizes):
""" Cut a matrix expression into Blocks
>>> from sympy import ImmutableMatrix, blockcut
>>> M = ImmutableMatrix(4, 4, range(16))
>>> B = blockcut(M, (1, 3), (1, 3))
>>> type(B).__name__
'BlockMatrix'
>>> ImmutableMatrix(B.blocks[0, 1])
Matrix([[1, 2, 3]])
"""
rowbounds = bounds(rowsizes)
colbounds = bounds(colsizes)
return BlockMatrix([[MatrixSlice(expr, rowbound, colbound)
for colbound in colbounds]
for rowbound in rowbounds])
|
8581961e8dd41e04f3c8b7fa44e9b3a081e70de93de86e9cd51e3dcb40a86bfa
|
from __future__ import print_function, division
from .matexpr import MatrixExpr
from sympy import Basic, sympify
from sympy.matrices import Matrix
from sympy.functions.elementary.complexes import re, im
class FunctionMatrix(MatrixExpr):
"""
Represents a Matrix using a function (Lambda)
This class is an alternative to SparseMatrix
>>> from sympy import FunctionMatrix, symbols, Lambda, MatPow, Matrix
>>> i, j = symbols('i,j')
>>> X = FunctionMatrix(3, 3, Lambda((i, j), i + j))
>>> Matrix(X)
Matrix([
[0, 1, 2],
[1, 2, 3],
[2, 3, 4]])
>>> Y = FunctionMatrix(1000, 1000, Lambda((i, j), i + j))
>>> isinstance(Y*Y, MatPow) # this is an expression object
True
>>> (Y**2)[10,10] # So this is evaluated lazily
342923500
"""
def __new__(cls, rows, cols, lamda):
rows, cols = sympify(rows), sympify(cols)
return Basic.__new__(cls, rows, cols, lamda)
@property
def shape(self):
return self.args[0:2]
@property
def lamda(self):
return self.args[2]
def _entry(self, i, j):
return self.lamda(i, j)
def _eval_trace(self):
from sympy.matrices.expressions.trace import Trace
from sympy import Sum
return Trace(self).rewrite(Sum).doit()
def as_real_imag(self):
return (re(Matrix(self)), im(Matrix(self)))
|
812f0dc98ec236bbc60cc4f94d4d4ce2b8519429bb59f76a1b2f9f503f614f4d
|
from __future__ import print_function, division
from sympy.core.compatibility import reduce
from operator import add
from sympy.core import Add, Basic, sympify
from sympy.functions import adjoint
from sympy.matrices.matrices import MatrixBase
from sympy.matrices.expressions.transpose import transpose
from sympy.strategies import (rm_id, unpack, flatten, sort, condition,
exhaust, do_one, glom)
from sympy.matrices.expressions.matexpr import MatrixExpr, ShapeError, ZeroMatrix
from sympy.utilities import default_sort_key, sift
from sympy.core.operations import AssocOp
class MatAdd(MatrixExpr, Add):
"""A Sum of Matrix Expressions
MatAdd inherits from and operates like SymPy Add
Examples
========
>>> from sympy import MatAdd, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 5)
>>> B = MatrixSymbol('B', 5, 5)
>>> C = MatrixSymbol('C', 5, 5)
>>> MatAdd(A, B, C)
A + B + C
"""
is_MatAdd = True
def __new__(cls, *args, **kwargs):
args = list(map(sympify, args))
check = kwargs.get('check', False)
obj = Basic.__new__(cls, *args)
if check:
if all(not isinstance(i, MatrixExpr) for i in args):
return Add.fromiter(args)
validate(*args)
return obj
@property
def shape(self):
return self.args[0].shape
def _entry(self, i, j, expand=None):
return Add(*[arg._entry(i, j) for arg in self.args])
def _eval_transpose(self):
return MatAdd(*[transpose(arg) for arg in self.args]).doit()
def _eval_adjoint(self):
return MatAdd(*[adjoint(arg) for arg in self.args]).doit()
def _eval_trace(self):
from .trace import trace
return Add(*[trace(arg) for arg in self.args]).doit()
def doit(self, **kwargs):
deep = kwargs.get('deep', True)
if deep:
args = [arg.doit(**kwargs) for arg in self.args]
else:
args = self.args
return canonicalize(MatAdd(*args))
def validate(*args):
if not all(arg.is_Matrix for arg in args):
raise TypeError("Mix of Matrix and Scalar symbols")
A = args[0]
for B in args[1:]:
if A.shape != B.shape:
raise ShapeError("Matrices %s and %s are not aligned"%(A, B))
factor_of = lambda arg: arg.as_coeff_mmul()[0]
matrix_of = lambda arg: unpack(arg.as_coeff_mmul()[1])
def combine(cnt, mat):
if cnt == 1:
return mat
else:
return cnt * mat
def merge_explicit(matadd):
""" Merge explicit MatrixBase arguments
Examples
========
>>> from sympy import MatrixSymbol, eye, Matrix, MatAdd, pprint
>>> from sympy.matrices.expressions.matadd import merge_explicit
>>> A = MatrixSymbol('A', 2, 2)
>>> B = eye(2)
>>> C = Matrix([[1, 2], [3, 4]])
>>> X = MatAdd(A, B, C)
>>> pprint(X)
[1 0] [1 2]
A + [ ] + [ ]
[0 1] [3 4]
>>> pprint(merge_explicit(X))
[2 2]
A + [ ]
[3 5]
"""
groups = sift(matadd.args, lambda arg: isinstance(arg, MatrixBase))
if len(groups[True]) > 1:
return MatAdd(*(groups[False] + [reduce(add, groups[True])]))
else:
return matadd
rules = (rm_id(lambda x: x == 0 or isinstance(x, ZeroMatrix)),
unpack,
flatten,
glom(matrix_of, factor_of, combine),
merge_explicit,
sort(default_sort_key))
canonicalize = exhaust(condition(lambda x: isinstance(x, MatAdd),
do_one(*rules)))
|
af1e0d6b2096dfac642d1442db7303f0ca76ff967522d604a02feb399c3ddb9d
|
from sympy.core import I, symbols, Basic, Mul
from sympy.functions import adjoint, transpose
from sympy.matrices import (Identity, Inverse, Matrix, MatrixSymbol, ZeroMatrix,
eye, ImmutableMatrix)
from sympy.matrices.expressions import Adjoint, Transpose, det, MatPow
from sympy.matrices.expressions.matmul import (factor_in_front, remove_ids,
MatMul, xxinv, any_zeros, unpack, only_squares)
from sympy.strategies import null_safe
from sympy import refine, Q, Symbol
n, m, l, k = symbols('n m l k', integer=True)
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
D = MatrixSymbol('D', n, n)
E = MatrixSymbol('E', m, n)
def test_adjoint():
assert adjoint(A*B) == Adjoint(B)*Adjoint(A)
assert adjoint(2*A*B) == 2*Adjoint(B)*Adjoint(A)
assert adjoint(2*I*C) == -2*I*Adjoint(C)
M = Matrix(2, 2, [1, 2 + I, 3, 4])
MA = Matrix(2, 2, [1, 3, 2 - I, 4])
assert adjoint(M) == MA
assert adjoint(2*M) == 2*MA
assert adjoint(MatMul(2, M)) == MatMul(2, MA).doit()
def test_transpose():
assert transpose(A*B) == Transpose(B)*Transpose(A)
assert transpose(2*A*B) == 2*Transpose(B)*Transpose(A)
assert transpose(2*I*C) == 2*I*Transpose(C)
M = Matrix(2, 2, [1, 2 + I, 3, 4])
MT = Matrix(2, 2, [1, 3, 2 + I, 4])
assert transpose(M) == MT
assert transpose(2*M) == 2*MT
assert transpose(MatMul(2, M)) == MatMul(2, MT).doit()
def test_factor_in_front():
assert factor_in_front(MatMul(A, 2, B, evaluate=False)) ==\
MatMul(2, A, B, evaluate=False)
def test_remove_ids():
assert remove_ids(MatMul(A, Identity(m), B, evaluate=False)) == \
MatMul(A, B, evaluate=False)
assert null_safe(remove_ids)(MatMul(Identity(n), evaluate=False)) == \
MatMul(Identity(n), evaluate=False)
def test_xxinv():
assert xxinv(MatMul(D, Inverse(D), D, evaluate=False)) == \
MatMul(Identity(n), D, evaluate=False)
def test_any_zeros():
assert any_zeros(MatMul(A, ZeroMatrix(m, k), evaluate=False)) == \
ZeroMatrix(n, k)
def test_unpack():
assert unpack(MatMul(A, evaluate=False)) == A
x = MatMul(A, B)
assert unpack(x) == x
def test_only_squares():
assert only_squares(C) == [C]
assert only_squares(C, D) == [C, D]
assert only_squares(C, A, A.T, D) == [C, A*A.T, D]
def test_determinant():
assert det(2*C) == 2**n*det(C)
assert det(2*C*D) == 2**n*det(C)*det(D)
assert det(3*C*A*A.T*D) == 3**n*det(C)*det(A*A.T)*det(D)
def test_doit():
assert MatMul(C, 2, D).args == (C, 2, D)
assert MatMul(C, 2, D).doit().args == (2, C, D)
assert MatMul(C, Transpose(D*C)).args == (C, Transpose(D*C))
assert MatMul(C, Transpose(D*C)).doit(deep=True).args == (C, C.T, D.T)
def test_doit_drills_down():
X = ImmutableMatrix([[1, 2], [3, 4]])
Y = ImmutableMatrix([[2, 3], [4, 5]])
assert MatMul(X, MatPow(Y, 2)).doit() == X*Y**2
assert MatMul(C, Transpose(D*C)).doit().args == (C, C.T, D.T)
def test_doit_deep_false_still_canonical():
assert (MatMul(C, Transpose(D*C), 2).doit(deep=False).args ==
(2, C, Transpose(D*C)))
def test_matmul_scalar_Matrix_doit():
# Issue 9053
X = Matrix([[1, 2], [3, 4]])
assert MatMul(2, X).doit() == 2*X
def test_matmul_sympify():
assert isinstance(MatMul(eye(1), eye(1)).args[0], Basic)
def test_collapse_MatrixBase():
A = Matrix([[1, 1], [1, 1]])
B = Matrix([[1, 2], [3, 4]])
assert MatMul(A, B).doit() == ImmutableMatrix([[4, 6], [4, 6]])
def test_refine():
assert refine(C*C.T*D, Q.orthogonal(C)).doit() == D
kC = k*C
assert refine(kC*C.T, Q.orthogonal(C)).doit() == k*Identity(n)
assert refine(kC* kC.T, Q.orthogonal(C)).doit() == (k**2)*Identity(n)
def test_matmul_no_matrices():
assert MatMul(1) == 1
assert MatMul(n, m) == n*m
assert not isinstance(MatMul(n, m), MatMul)
def test_matmul_args_cnc():
a, b = symbols('a b', commutative=False)
assert MatMul(n, a, b, A, A.T).args_cnc() == ([n], [a, b, A, A.T])
assert MatMul(A, A.T).args_cnc() == ([1], [A, A.T])
def test_issue_12950():
M = Matrix([[Symbol("x")]]) * MatrixSymbol("A", 1, 1)
assert MatrixSymbol("A", 1, 1).as_explicit()[0]*Symbol('x') == M.as_explicit()[0]
def test_construction_with_Mul():
assert Mul(C, D) == MatMul(C, D)
assert Mul(D, C) == MatMul(D, C)
|
1bae7c092b1c03fc07b29d15cd411be78d20ee91d075aeb4b9b046d70d127c42
|
from sympy.utilities.pytest import raises
from sympy.core import symbols, pi, S
from sympy.matrices import Identity, MatrixSymbol, ImmutableMatrix, ZeroMatrix
from sympy.matrices.expressions import MatPow, MatAdd, MatMul
from sympy.matrices.expressions.matexpr import ShapeError
n, m, l, k = symbols('n m l k', integer=True)
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
D = MatrixSymbol('D', n, n)
E = MatrixSymbol('E', m, n)
def test_entry():
from sympy.concrete import Sum
assert MatPow(A, 1)[0, 0] == A[0, 0]
assert MatPow(C, 0)[0, 0] == 1
assert MatPow(C, 0)[0, 1] == 0
assert isinstance(MatPow(C, 2)[0, 0], Sum)
def test_as_explicit_symbol():
X = MatrixSymbol('X', 2, 2)
assert MatPow(X, 0).as_explicit() == ImmutableMatrix(Identity(2))
assert MatPow(X, 1).as_explicit() == X.as_explicit()
assert MatPow(X, 2).as_explicit() == (X.as_explicit())**2
def test_as_explicit_nonsquare_symbol():
X = MatrixSymbol('X', 2, 3)
assert MatPow(X, 1).as_explicit() == X.as_explicit()
for r in [0, 2, S.Half, S.Pi]:
raises(ShapeError, lambda: MatPow(X, r).as_explicit())
def test_as_explicit():
A = ImmutableMatrix([[1, 2], [3, 4]])
assert MatPow(A, 0).as_explicit() == ImmutableMatrix(Identity(2))
assert MatPow(A, 1).as_explicit() == A
assert MatPow(A, 2).as_explicit() == A**2
assert MatPow(A, -1).as_explicit() == A.inv()
assert MatPow(A, -2).as_explicit() == (A.inv())**2
# less expensive than testing on a 2x2
A = ImmutableMatrix([4]);
assert MatPow(A, S.Half).as_explicit() == A**S.Half
def test_as_explicit_nonsquare():
A = ImmutableMatrix([[1, 2, 3], [4, 5, 6]])
assert MatPow(A, 1).as_explicit() == A
raises(ShapeError, lambda: MatPow(A, 0).as_explicit())
raises(ShapeError, lambda: MatPow(A, 2).as_explicit())
raises(ShapeError, lambda: MatPow(A, -1).as_explicit())
raises(ValueError, lambda: MatPow(A, pi).as_explicit())
def test_doit_nonsquare_MatrixSymbol():
assert MatPow(A, 1).doit() == A
for r in [0, 2, -1, pi]:
assert MatPow(A, r).doit() == MatPow(A, r)
def test_doit_square_MatrixSymbol_symsize():
assert MatPow(C, 0).doit() == Identity(n)
assert MatPow(C, 1).doit() == C
for r in [2, pi]:
assert MatPow(C, r).doit() == MatPow(C, r)
def test_doit_with_MatrixBase():
X = ImmutableMatrix([[1, 2], [3, 4]])
assert MatPow(X, 0).doit() == ImmutableMatrix(Identity(2))
assert MatPow(X, 1).doit() == X
assert MatPow(X, 2).doit() == X**2
assert MatPow(X, -1).doit() == X.inv()
assert MatPow(X, -2).doit() == (X.inv())**2
# less expensive than testing on a 2x2
assert MatPow(ImmutableMatrix([4]), S.Half).doit() == ImmutableMatrix([2])
def test_doit_nonsquare():
X = ImmutableMatrix([[1, 2, 3], [4, 5, 6]])
assert MatPow(X, 1).doit() == X
raises(ShapeError, lambda: MatPow(X, 0).doit())
raises(ShapeError, lambda: MatPow(X, 2).doit())
raises(ShapeError, lambda: MatPow(X, -1).doit())
raises(ShapeError, lambda: MatPow(X, pi).doit())
def test_doit_nested_MatrixExpr():
X = ImmutableMatrix([[1, 2], [3, 4]])
Y = ImmutableMatrix([[2, 3], [4, 5]])
assert MatPow(MatMul(X, Y), 2).doit() == (X*Y)**2
assert MatPow(MatAdd(X, Y), 2).doit() == (X + Y)**2
def test_identity_power():
k = Identity(n)
assert MatPow(k, 4).doit() == k
assert MatPow(k, n).doit() == k
assert MatPow(k, -3).doit() == k
assert MatPow(k, 0).doit() == k
l = Identity(3)
assert MatPow(l, n).doit() == l
assert MatPow(l, -1).doit() == l
assert MatPow(l, 0).doit() == l
def test_zero_power():
z1 = ZeroMatrix(n, n)
assert MatPow(z1, 3).doit() == z1
raises(ValueError, lambda:MatPow(z1, -1).doit())
assert MatPow(z1, 0).doit() == Identity(n)
assert MatPow(z1, n).doit() == z1
raises(ValueError, lambda:MatPow(z1, -2).doit())
z2 = ZeroMatrix(4, 4)
assert MatPow(z2, n).doit() == z2
raises(ValueError, lambda:MatPow(z2, -3).doit())
assert MatPow(z2, 2).doit() == z2
assert MatPow(z2, 0).doit() == Identity(4)
raises(ValueError, lambda:MatPow(z2, -1).doit())
def test_transpose_power():
from sympy.matrices.expressions.transpose import Transpose as TP
assert (C*D).T**5 == ((C*D)**5).T == (D.T * C.T)**5
assert ((C*D).T**5).T == (C*D)**5
assert (C.T.I.T)**7 == C**-7
assert (C.T**l).T**k == C**(l*k)
assert ((E.T * A.T)**5).T == (A*E)**5
assert ((A*E).T**5).T**7 == (A*E)**35
assert TP(TP(C**2 * D**3)**5).doit() == (C**2 * D**3)**5
assert ((D*C)**-5).T**-5 == ((D*C)**25).T
assert (((D*C)**l).T**k).T == (D*C)**(l*k)
|
b7b030dd33500b0720f31e0e860d88466315826c949e11246ccc4b73afec029c
|
from sympy import KroneckerDelta, diff, Piecewise, And
from sympy import Sum, Dummy, factor, expand
from sympy.core import S, symbols, Add, Mul
from sympy.core.compatibility import long
from sympy.functions import transpose, sin, cos, sqrt, cbrt
from sympy.simplify import simplify
from sympy.matrices import (Identity, ImmutableMatrix, Inverse, MatAdd, MatMul,
MatPow, Matrix, MatrixExpr, MatrixSymbol, ShapeError, ZeroMatrix,
SparseMatrix, Transpose, Adjoint)
from sympy.matrices.expressions.matexpr import MatrixElement
from sympy.utilities.pytest import raises
n, m, l, k, p = symbols('n m l k p', integer=True)
x = symbols('x')
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
D = MatrixSymbol('D', n, n)
E = MatrixSymbol('E', m, n)
w = MatrixSymbol('w', n, 1)
def test_shape():
assert A.shape == (n, m)
assert (A*B).shape == (n, l)
raises(ShapeError, lambda: B*A)
def test_matexpr():
assert (x*A).shape == A.shape
assert (x*A).__class__ == MatMul
assert 2*A - A - A == ZeroMatrix(*A.shape)
assert (A*B).shape == (n, l)
def test_subs():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', m, l)
assert A.subs(n, m).shape == (m, m)
assert (A*B).subs(B, C) == A*C
assert (A*B).subs(l, n).is_square
def test_ZeroMatrix():
A = MatrixSymbol('A', n, m)
Z = ZeroMatrix(n, m)
assert A + Z == A
assert A*Z.T == ZeroMatrix(n, n)
assert Z*A.T == ZeroMatrix(n, n)
assert A - A == ZeroMatrix(*A.shape)
assert not Z
assert transpose(Z) == ZeroMatrix(m, n)
assert Z.conjugate() == Z
assert ZeroMatrix(n, n)**0 == Identity(n)
with raises(ShapeError):
Z**0
with raises(ShapeError):
Z**2
def test_ZeroMatrix_doit():
Znn = ZeroMatrix(Add(n, n, evaluate=False), n)
assert isinstance(Znn.rows, Add)
assert Znn.doit() == ZeroMatrix(2*n, n)
assert isinstance(Znn.doit().rows, Mul)
def test_Identity():
A = MatrixSymbol('A', n, m)
i, j = symbols('i j')
In = Identity(n)
Im = Identity(m)
assert A*Im == A
assert In*A == A
assert transpose(In) == In
assert In.inverse() == In
assert In.conjugate() == In
assert In[i, j] != 0
assert Sum(In[i, j], (i, 0, n-1), (j, 0, n-1)).subs(n,3).doit() == 3
assert Sum(Sum(In[i, j], (i, 0, n-1)), (j, 0, n-1)).subs(n,3).doit() == 3
def test_Identity_doit():
Inn = Identity(Add(n, n, evaluate=False))
assert isinstance(Inn.rows, Add)
assert Inn.doit() == Identity(2*n)
assert isinstance(Inn.doit().rows, Mul)
def test_addition():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', n, m)
assert isinstance(A + B, MatAdd)
assert (A + B).shape == A.shape
assert isinstance(A - A + 2*B, MatMul)
raises(ShapeError, lambda: A + B.T)
raises(TypeError, lambda: A + 1)
raises(TypeError, lambda: 5 + A)
raises(TypeError, lambda: 5 - A)
assert A + ZeroMatrix(n, m) - A == ZeroMatrix(n, m)
with raises(TypeError):
ZeroMatrix(n,m) + S(0)
def test_multiplication():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
C = MatrixSymbol('C', n, n)
assert (2*A*B).shape == (n, l)
assert (A*0*B) == ZeroMatrix(n, l)
raises(ShapeError, lambda: B*A)
assert (2*A).shape == A.shape
assert A * ZeroMatrix(m, m) * B == ZeroMatrix(n, l)
assert C * Identity(n) * C.I == Identity(n)
assert B/2 == S.Half*B
raises(NotImplementedError, lambda: 2/B)
A = MatrixSymbol('A', n, n)
B = MatrixSymbol('B', n, n)
assert Identity(n) * (A + B) == A + B
assert A**2*A == A**3
assert A**2*(A.I)**3 == A.I
assert A**3*(A.I)**2 == A
def test_MatPow():
A = MatrixSymbol('A', n, n)
AA = MatPow(A, 2)
assert AA.exp == 2
assert AA.base == A
assert (A**n).exp == n
assert A**0 == Identity(n)
assert A**1 == A
assert A**2 == AA
assert A**-1 == Inverse(A)
assert (A**-1)**-1 == A
assert (A**2)**3 == A**6
assert A**S.Half == sqrt(A)
assert A**(S(1)/3) == cbrt(A)
raises(ShapeError, lambda: MatrixSymbol('B', 3, 2)**2)
def test_MatrixSymbol():
n, m, t = symbols('n,m,t')
X = MatrixSymbol('X', n, m)
assert X.shape == (n, m)
raises(TypeError, lambda: MatrixSymbol('X', n, m)(t)) # issue 5855
assert X.doit() == X
def test_dense_conversion():
X = MatrixSymbol('X', 2, 2)
assert ImmutableMatrix(X) == ImmutableMatrix(2, 2, lambda i, j: X[i, j])
assert Matrix(X) == Matrix(2, 2, lambda i, j: X[i, j])
def test_free_symbols():
assert (C*D).free_symbols == set((C, D))
def test_zero_matmul():
assert isinstance(S.Zero * MatrixSymbol('X', 2, 2), MatrixExpr)
def test_matadd_simplify():
A = MatrixSymbol('A', 1, 1)
assert simplify(MatAdd(A, ImmutableMatrix([[sin(x)**2 + cos(x)**2]]))) == \
MatAdd(A, ImmutableMatrix([[1]]))
def test_matmul_simplify():
A = MatrixSymbol('A', 1, 1)
assert simplify(MatMul(A, ImmutableMatrix([[sin(x)**2 + cos(x)**2]]))) == \
MatMul(A, ImmutableMatrix([[1]]))
def test_invariants():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', m, l)
X = MatrixSymbol('X', n, n)
objs = [Identity(n), ZeroMatrix(m, n), A, MatMul(A, B), MatAdd(A, A),
Transpose(A), Adjoint(A), Inverse(X), MatPow(X, 2), MatPow(X, -1),
MatPow(X, 0)]
for obj in objs:
assert obj == obj.__class__(*obj.args)
def test_indexing():
A = MatrixSymbol('A', n, m)
A[1, 2]
A[l, k]
A[l+1, k+1]
def test_single_indexing():
A = MatrixSymbol('A', 2, 3)
assert A[1] == A[0, 1]
assert A[long(1)] == A[0, 1]
assert A[3] == A[1, 0]
assert list(A[:2, :2]) == [A[0, 0], A[0, 1], A[1, 0], A[1, 1]]
raises(IndexError, lambda: A[6])
raises(IndexError, lambda: A[n])
B = MatrixSymbol('B', n, m)
raises(IndexError, lambda: B[1])
B = MatrixSymbol('B', n, 3)
assert B[3] == B[1, 0]
def test_MatrixElement_commutative():
assert A[0, 1]*A[1, 0] == A[1, 0]*A[0, 1]
def test_MatrixSymbol_determinant():
A = MatrixSymbol('A', 4, 4)
assert A.as_explicit().det() == A[0, 0]*A[1, 1]*A[2, 2]*A[3, 3] - \
A[0, 0]*A[1, 1]*A[2, 3]*A[3, 2] - A[0, 0]*A[1, 2]*A[2, 1]*A[3, 3] + \
A[0, 0]*A[1, 2]*A[2, 3]*A[3, 1] + A[0, 0]*A[1, 3]*A[2, 1]*A[3, 2] - \
A[0, 0]*A[1, 3]*A[2, 2]*A[3, 1] - A[0, 1]*A[1, 0]*A[2, 2]*A[3, 3] + \
A[0, 1]*A[1, 0]*A[2, 3]*A[3, 2] + A[0, 1]*A[1, 2]*A[2, 0]*A[3, 3] - \
A[0, 1]*A[1, 2]*A[2, 3]*A[3, 0] - A[0, 1]*A[1, 3]*A[2, 0]*A[3, 2] + \
A[0, 1]*A[1, 3]*A[2, 2]*A[3, 0] + A[0, 2]*A[1, 0]*A[2, 1]*A[3, 3] - \
A[0, 2]*A[1, 0]*A[2, 3]*A[3, 1] - A[0, 2]*A[1, 1]*A[2, 0]*A[3, 3] + \
A[0, 2]*A[1, 1]*A[2, 3]*A[3, 0] + A[0, 2]*A[1, 3]*A[2, 0]*A[3, 1] - \
A[0, 2]*A[1, 3]*A[2, 1]*A[3, 0] - A[0, 3]*A[1, 0]*A[2, 1]*A[3, 2] + \
A[0, 3]*A[1, 0]*A[2, 2]*A[3, 1] + A[0, 3]*A[1, 1]*A[2, 0]*A[3, 2] - \
A[0, 3]*A[1, 1]*A[2, 2]*A[3, 0] - A[0, 3]*A[1, 2]*A[2, 0]*A[3, 1] + \
A[0, 3]*A[1, 2]*A[2, 1]*A[3, 0]
def test_MatrixElement_diff():
assert (A[3, 0]*A[0, 0]).diff(A[0, 0]) == A[3, 0]
def test_MatrixElement_doit():
u = MatrixSymbol('u', 2, 1)
v = ImmutableMatrix([3, 5])
assert u[0, 0].subs(u, v).doit() == v[0, 0]
def test_identity_powers():
M = Identity(n)
assert MatPow(M, 3).doit() == M**3
assert M**n == M
assert MatPow(M, 0).doit() == M**2
assert M**-2 == M
assert MatPow(M, -2).doit() == M**0
N = Identity(3)
assert MatPow(N, 2).doit() == N**n
assert MatPow(N, 3).doit() == N
assert MatPow(N, -2).doit() == N**4
assert MatPow(N, 2).doit() == N**0
def test_Zero_power():
z1 = ZeroMatrix(n, n)
assert z1**4 == z1
raises(ValueError, lambda:z1**-2)
assert z1**0 == Identity(n)
assert MatPow(z1, 2).doit() == z1**2
raises(ValueError, lambda:MatPow(z1, -2).doit())
z2 = ZeroMatrix(3, 3)
assert MatPow(z2, 4).doit() == z2**4
raises(ValueError, lambda:z2**-3)
assert z2**3 == MatPow(z2, 3).doit()
assert z2**0 == Identity(3)
raises(ValueError, lambda:MatPow(z2, -1).doit())
def test_matrixelement_diff():
dexpr = diff((D*w)[k,0], w[p,0])
assert w[k, p].diff(w[k, p]) == 1
assert w[k, p].diff(w[0, 0]) == KroneckerDelta(0, k)*KroneckerDelta(0, p)
assert str(dexpr) == "Sum(KroneckerDelta(_i_1, p)*D[k, _i_1], (_i_1, 0, n - 1))"
assert str(dexpr.doit()) == 'Piecewise((D[k, p], (p >= 0) & (p <= n - 1)), (0, True))'
# TODO: bug with .dummy_eq( ), the previous 2 lines should be replaced by:
return # stop eval
_i_1 = Dummy("_i_1")
assert dexpr.dummy_eq(Sum(KroneckerDelta(_i_1, p)*D[k, _i_1], (_i_1, 0, n - 1)))
assert dexpr.doit().dummy_eq(Piecewise((D[k, p], (p >= 0) & (p <= n - 1)), (0, True)))
def test_MatrixElement_with_values():
x, y, z, w = symbols("x y z w")
M = Matrix([[x, y], [z, w]])
i, j = symbols("i, j")
Mij = M[i, j]
assert isinstance(Mij, MatrixElement)
Ms = SparseMatrix([[2, 3], [4, 5]])
msij = Ms[i, j]
assert isinstance(msij, MatrixElement)
for oi, oj in [(0, 0), (0, 1), (1, 0), (1, 1)]:
assert Mij.subs({i: oi, j: oj}) == M[oi, oj]
assert msij.subs({i: oi, j: oj}) == Ms[oi, oj]
A = MatrixSymbol("A", 2, 2)
assert A[0, 0].subs(A, M) == x
assert A[i, j].subs(A, M) == M[i, j]
assert M[i, j].subs(M, A) == A[i, j]
assert isinstance(M[3*i - 2, j], MatrixElement)
assert M[3*i - 2, j].subs({i: 1, j: 0}) == M[1, 0]
assert isinstance(M[i, 0], MatrixElement)
assert M[i, 0].subs(i, 0) == M[0, 0]
assert M[0, i].subs(i, 1) == M[0, 1]
assert M[i, j].diff(x) == Matrix([[1, 0], [0, 0]])[i, j]
raises(ValueError, lambda: M[i, 2])
raises(ValueError, lambda: M[i, -1])
raises(ValueError, lambda: M[2, i])
raises(ValueError, lambda: M[-1, i])
def test_inv():
B = MatrixSymbol('B', 3, 3)
assert B.inv() == B**-1
def test_factor_expand():
A = MatrixSymbol("A", n, n)
B = MatrixSymbol("B", n, n)
expr1 = (A + B)*(C + D)
expr2 = A*C + B*C + A*D + B*D
assert expr1 != expr2
assert expand(expr1) == expr2
assert factor(expr2) == expr1
|
d5080761cc971108446a70856c65866519da07b78118675e208779928055ed55
|
from sympy import I, symbols, Matrix, eye, Mod, floor
from sympy.matrices import ShapeError, MatrixSymbol, Identity
from sympy.matrices.expressions import det, trace
from sympy.matrices.expressions.kronecker import (KroneckerProduct,
kronecker_product,
combine_kronecker)
from sympy.core.trace import Tr
mat1 = Matrix([[1, 2 * I], [1 + I, 3]])
mat2 = Matrix([[2 * I, 3], [4 * I, 2]])
i, j, k, n, m, o, p, x = symbols('i,j,k,n,m,o,p,x')
Z = MatrixSymbol('Z', n, n)
W = MatrixSymbol('W', m, m)
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', n, m)
C = MatrixSymbol('C', m, k)
def test_KroneckerProduct():
assert isinstance(KroneckerProduct(A, B), KroneckerProduct)
assert KroneckerProduct(A, B).subs(A, C) == KroneckerProduct(C, B)
assert KroneckerProduct(A, C).shape == (n*m, m*k)
assert (KroneckerProduct(A, C) + KroneckerProduct(-A, C)).is_ZeroMatrix
assert (KroneckerProduct(W, Z) * KroneckerProduct(W.I, Z.I)).is_Identity
def test_KroneckerProduct_identity():
assert KroneckerProduct(Identity(m), Identity(n)) == Identity(m*n)
assert KroneckerProduct(eye(2), eye(3)) == eye(6)
def test_KroneckerProduct_explicit():
X = MatrixSymbol('X', 2, 2)
Y = MatrixSymbol('Y', 2, 2)
kp = KroneckerProduct(X, Y)
assert kp.shape == (4, 4)
assert kp.as_explicit() == Matrix(
[
[X[0, 0]*Y[0, 0], X[0, 0]*Y[0, 1], X[0, 1]*Y[0, 0], X[0, 1]*Y[0, 1]],
[X[0, 0]*Y[1, 0], X[0, 0]*Y[1, 1], X[0, 1]*Y[1, 0], X[0, 1]*Y[1, 1]],
[X[1, 0]*Y[0, 0], X[1, 0]*Y[0, 1], X[1, 1]*Y[0, 0], X[1, 1]*Y[0, 1]],
[X[1, 0]*Y[1, 0], X[1, 0]*Y[1, 1], X[1, 1]*Y[1, 0], X[1, 1]*Y[1, 1]]
]
)
def test_tensor_product_adjoint():
assert KroneckerProduct(I*A, B).adjoint() == \
-I*KroneckerProduct(A.adjoint(), B.adjoint())
assert KroneckerProduct(mat1, mat2).adjoint() == \
kronecker_product(mat1.adjoint(), mat2.adjoint())
def test_tensor_product_conjugate():
assert KroneckerProduct(I*A, B).conjugate() == \
-I*KroneckerProduct(A.conjugate(), B.conjugate())
assert KroneckerProduct(mat1, mat2).conjugate() == \
kronecker_product(mat1.conjugate(), mat2.conjugate())
def test_tensor_product_transpose():
assert KroneckerProduct(I*A, B).transpose() == \
I*KroneckerProduct(A.transpose(), B.transpose())
assert KroneckerProduct(mat1, mat2).transpose() == \
kronecker_product(mat1.transpose(), mat2.transpose())
def test_KroneckerProduct_is_associative():
assert kronecker_product(A, kronecker_product(
B, C)) == kronecker_product(kronecker_product(A, B), C)
assert kronecker_product(A, kronecker_product(
B, C)) == KroneckerProduct(A, B, C)
def test_KroneckerProduct_is_bilinear():
assert kronecker_product(x*A, B) == x*kronecker_product(A, B)
assert kronecker_product(A, x*B) == x*kronecker_product(A, B)
def test_KroneckerProduct_determinant():
kp = kronecker_product(W, Z)
assert det(kp) == det(W)**n * det(Z)**m
def test_KroneckerProduct_trace():
kp = kronecker_product(W, Z)
assert trace(kp) == trace(W)*trace(Z)
def test_KroneckerProduct_isnt_commutative():
assert KroneckerProduct(A, B) != KroneckerProduct(B, A)
assert KroneckerProduct(A, B).is_commutative is False
def test_KroneckerProduct_extracts_commutative_part():
assert kronecker_product(x * A, 2 * B) == x * \
2 * KroneckerProduct(A, B)
def test_KroneckerProduct_inverse():
kp = kronecker_product(W, Z)
assert kp.inverse() == kronecker_product(W.inverse(), Z.inverse())
def test_KroneckerProduct_combine_add():
kp1 = kronecker_product(A, B)
kp2 = kronecker_product(C, W)
assert combine_kronecker(kp1*kp2) == kronecker_product(A*C, B*W)
def test_KroneckerProduct_combine_mul():
X = MatrixSymbol('X', m, n)
Y = MatrixSymbol('Y', m, n)
kp1 = kronecker_product(A, X)
kp2 = kronecker_product(B, Y)
assert combine_kronecker(kp1+kp2) == kronecker_product(A+B, X+Y)
def test_KroneckerProduct_combine_pow():
X = MatrixSymbol('X', n, n)
Y = MatrixSymbol('Y', n, n)
assert combine_kronecker(KroneckerProduct(
X, Y)**x) == KroneckerProduct(X**x, Y**x)
assert combine_kronecker(x * KroneckerProduct(X, Y)
** 2) == x * KroneckerProduct(X**2, Y**2)
assert combine_kronecker(
x * (KroneckerProduct(X, Y)**2) * KroneckerProduct(A, B)) == x * KroneckerProduct(X**2 * A, Y**2 * B)
def test_KroneckerProduct_expand():
X = MatrixSymbol('X', n, n)
Y = MatrixSymbol('Y', n, n)
assert KroneckerProduct(X + Y, Y + Z).expand(kroneckerproduct=True) == \
KroneckerProduct(X, Y) + KroneckerProduct(X, Z) + \
KroneckerProduct(Y, Y) + KroneckerProduct(Y, Z)
def test_KroneckerProduct_entry():
A = MatrixSymbol('A', n, m)
B = MatrixSymbol('B', o, p)
assert KroneckerProduct(A, B)._entry(i, j) == A[Mod(floor(i/o), n), Mod(floor(j/p), m)]*B[Mod(i, o), Mod(j, p)]
|
945b2ae8ca8dbc9b63e171c2d96101abba620e37b5b6d0ed73c4693b1d148395
|
from sympy.core import Lambda, S, symbols
from sympy.concrete import Sum
from sympy.functions import adjoint, conjugate, transpose
from sympy.matrices import eye, Matrix, ShapeError, ImmutableMatrix
from sympy.matrices.expressions import (
Adjoint, Identity, FunctionMatrix, MatrixExpr, MatrixSymbol, Trace,
ZeroMatrix, trace, MatPow, MatAdd, MatMul
)
from sympy.utilities.pytest import raises, XFAIL
n = symbols('n', integer=True)
A = MatrixSymbol('A', n, n)
B = MatrixSymbol('B', n, n)
C = MatrixSymbol('C', 3, 4)
def test_Trace():
assert isinstance(Trace(A), Trace)
assert not isinstance(Trace(A), MatrixExpr)
raises(ShapeError, lambda: Trace(C))
assert trace(eye(3)) == 3
assert trace(Matrix(3, 3, [1, 2, 3, 4, 5, 6, 7, 8, 9])) == 15
assert adjoint(Trace(A)) == trace(Adjoint(A))
assert conjugate(Trace(A)) == trace(Adjoint(A))
assert transpose(Trace(A)) == Trace(A)
A / Trace(A) # Make sure this is possible
# Some easy simplifications
assert trace(Identity(5)) == 5
assert trace(ZeroMatrix(5, 5)) == 0
assert trace(2*A*B) == 2*Trace(A*B)
assert trace(A.T) == trace(A)
i, j = symbols('i j')
F = FunctionMatrix(3, 3, Lambda((i, j), i + j))
assert trace(F) == (0 + 0) + (1 + 1) + (2 + 2)
raises(TypeError, lambda: Trace(S.One))
assert Trace(A).arg is A
assert str(trace(A)) == str(Trace(A).doit())
def test_Trace_A_plus_B():
assert trace(A + B) == Trace(A) + Trace(B)
assert Trace(A + B).arg == MatAdd(A, B)
assert Trace(A + B).doit() == Trace(A) + Trace(B)
def test_Trace_MatAdd_doit():
# See issue #9028
X = ImmutableMatrix([[1, 2, 3]]*3)
Y = MatrixSymbol('Y', 3, 3)
q = MatAdd(X, 2*X, Y, -3*Y)
assert Trace(q).arg == q
assert Trace(q).doit() == 18 - 2*Trace(Y)
def test_Trace_MatPow_doit():
X = Matrix([[1, 2], [3, 4]])
assert Trace(X).doit() == 5
q = MatPow(X, 2)
assert Trace(q).arg == q
assert Trace(q).doit() == 29
def test_Trace_MutableMatrix_plus():
# See issue #9043
X = Matrix([[1, 2], [3, 4]])
assert Trace(X) + Trace(X) == 2*Trace(X)
def test_Trace_doit_deep_False():
X = Matrix([[1, 2], [3, 4]])
q = MatPow(X, 2)
assert Trace(q).doit(deep=False).arg == q
q = MatAdd(X, 2*X)
assert Trace(q).doit(deep=False).arg == q
q = MatMul(X, 2*X)
assert Trace(q).doit(deep=False).arg == q
def test_trace_constant_factor():
# Issue 9052: gave 2*Trace(MatMul(A)) instead of 2*Trace(A)
assert trace(2*A) == 2*Trace(A)
X = ImmutableMatrix([[1, 2], [3, 4]])
assert trace(MatMul(2, X)) == 10
def test_rewrite():
assert isinstance(trace(A).rewrite(Sum), Sum)
|
2fb761a1a0ec99b6457bf120f5a270f44018c372e4d47aefd62c0dd130d2e29a
|
from sympy.sets.setexpr import SetExpr
from sympy.utilities.pytest import XFAIL
from sympy.sets import Interval, FiniteSet, Intersection, ImageSet, Union
from sympy import (Expr, Set, exp, log, sin, cos, Symbol, Min, Max, S, oo,
symbols, Lambda, sqrt, Pow, Dummy, tan, pi, Mul)
I = Interval(0, 2)
a, x = symbols("a, x")
_d = Dummy("d")
def test_setexpr():
se = SetExpr(Interval(0, 1))
assert isinstance(se.set, Set)
assert isinstance(se, Expr)
def test_scalar_funcs():
assert SetExpr(Interval(0, 1)).set == Interval(0, 1)
a, b = Symbol('a', real=True), Symbol('b', real=True)
a, b = 1, 2
# TODO: add support for more functions in the future:
for f in [exp, log]:
input_se = f(SetExpr(Interval(a, b)))
output = input_se.set
expected = Interval(Min(f(a), f(b)), Max(f(a), f(b)))
assert output == expected
def test_Add_Mul():
assert (SetExpr(Interval(0, 1)) + 1).set == Interval(1, 2)
assert (SetExpr(Interval(0, 1)) * 2).set == Interval(0, 2)
def test_Pow():
assert (SetExpr(Interval(0, 2))**2).set == Interval(0, 4)
def test_compound():
assert (exp(SetExpr(Interval(0, 1)) * 2 + 1)).set == \
Interval(exp(1), exp(3))
def test_Interval_Interval():
assert (SetExpr(Interval(1, 2)) + SetExpr(Interval(10, 20))).set == \
Interval(11, 22)
assert (SetExpr(Interval(1, 2)) * SetExpr(Interval(10, 20))).set == \
Interval(10, 40)
def test_FiniteSet_FiniteSet():
assert (SetExpr(FiniteSet(1, 2, 3)) + SetExpr(FiniteSet(1, 2))).set ==\
FiniteSet(2, 3, 4, 5)
assert (SetExpr(FiniteSet(1, 2, 3)) * SetExpr(FiniteSet(1, 2))).set ==\
FiniteSet(1, 2, 3, 4, 6)
def test_Interval_FiniteSet():
assert (SetExpr(FiniteSet(1, 2)) + SetExpr(Interval(0, 10))).set == \
Interval(1, 12)
def test_Many_Sets():
assert (SetExpr(Interval(0, 1)) +
SetExpr(Interval(2, 3)) +
SetExpr(FiniteSet(10, 11, 12))).set == Interval(12, 16)
def test_same_setexprs_are_not_identical():
a = SetExpr(FiniteSet(0, 1))
b = SetExpr(FiniteSet(0, 1))
assert (a + b).set == FiniteSet(0, 1, 2)
# Cannont detect the set being the same:
# assert (a + a).set == FiniteSet(0, 2)
def test_Interval_arithmetic():
i12cc = SetExpr(Interval(1, 2))
i12lo = SetExpr(Interval.Lopen(1, 2))
i12ro = SetExpr(Interval.Ropen(1, 2))
i12o = SetExpr(Interval.open(1, 2))
n23cc = SetExpr(Interval(-2, 3))
n23lo = SetExpr(Interval.Lopen(-2, 3))
n23ro = SetExpr(Interval.Ropen(-2, 3))
n23o = SetExpr(Interval.open(-2, 3))
n3n2cc = SetExpr(Interval(-3, -2))
assert i12cc + i12cc == SetExpr(Interval(2, 4))
assert i12cc - i12cc == SetExpr(Interval(-1, 1))
assert i12cc * i12cc == SetExpr(Interval(1, 4))
assert i12cc / i12cc == SetExpr(Interval(S.Half, 2))
assert i12cc ** 2 == SetExpr(Interval(1, 4))
assert i12cc ** 3 == SetExpr(Interval(1, 8))
assert i12lo + i12ro == SetExpr(Interval.open(2, 4))
assert i12lo - i12ro == SetExpr(Interval.Lopen(-1, 1))
assert i12lo * i12ro == SetExpr(Interval.open(1, 4))
assert i12lo / i12ro == SetExpr(Interval.Lopen(S.Half, 2))
assert i12lo + i12lo == SetExpr(Interval.Lopen(2, 4))
assert i12lo - i12lo == SetExpr(Interval.open(-1, 1))
assert i12lo * i12lo == SetExpr(Interval.Lopen(1, 4))
assert i12lo / i12lo == SetExpr(Interval.open(S.Half, 2))
assert i12lo + i12cc == SetExpr(Interval.Lopen(2, 4))
assert i12lo - i12cc == SetExpr(Interval.Lopen(-1, 1))
assert i12lo * i12cc == SetExpr(Interval.Lopen(1, 4))
assert i12lo / i12cc == SetExpr(Interval.Lopen(S.Half, 2))
assert i12lo + i12o == SetExpr(Interval.open(2, 4))
assert i12lo - i12o == SetExpr(Interval.open(-1, 1))
assert i12lo * i12o == SetExpr(Interval.open(1, 4))
assert i12lo / i12o == SetExpr(Interval.open(S.Half, 2))
assert i12lo ** 2 == SetExpr(Interval.Lopen(1, 4))
assert i12lo ** 3 == SetExpr(Interval.Lopen(1, 8))
assert i12ro + i12ro == SetExpr(Interval.Ropen(2, 4))
assert i12ro - i12ro == SetExpr(Interval.open(-1, 1))
assert i12ro * i12ro == SetExpr(Interval.Ropen(1, 4))
assert i12ro / i12ro == SetExpr(Interval.open(S.Half, 2))
assert i12ro + i12cc == SetExpr(Interval.Ropen(2, 4))
assert i12ro - i12cc == SetExpr(Interval.Ropen(-1, 1))
assert i12ro * i12cc == SetExpr(Interval.Ropen(1, 4))
assert i12ro / i12cc == SetExpr(Interval.Ropen(S.Half, 2))
assert i12ro + i12o == SetExpr(Interval.open(2, 4))
assert i12ro - i12o == SetExpr(Interval.open(-1, 1))
assert i12ro * i12o == SetExpr(Interval.open(1, 4))
assert i12ro / i12o == SetExpr(Interval.open(S.Half, 2))
assert i12ro ** 2 == SetExpr(Interval.Ropen(1, 4))
assert i12ro ** 3 == SetExpr(Interval.Ropen(1, 8))
assert i12o + i12lo == SetExpr(Interval.open(2, 4))
assert i12o - i12lo == SetExpr(Interval.open(-1, 1))
assert i12o * i12lo == SetExpr(Interval.open(1, 4))
assert i12o / i12lo == SetExpr(Interval.open(S.Half, 2))
assert i12o + i12ro == SetExpr(Interval.open(2, 4))
assert i12o - i12ro == SetExpr(Interval.open(-1, 1))
assert i12o * i12ro == SetExpr(Interval.open(1, 4))
assert i12o / i12ro == SetExpr(Interval.open(S.Half, 2))
assert i12o + i12cc == SetExpr(Interval.open(2, 4))
assert i12o - i12cc == SetExpr(Interval.open(-1, 1))
assert i12o * i12cc == SetExpr(Interval.open(1, 4))
assert i12o / i12cc == SetExpr(Interval.open(S.Half, 2))
assert i12o ** 2 == SetExpr(Interval.open(1, 4))
assert i12o ** 3 == SetExpr(Interval.open(1, 8))
assert n23cc + n23cc == SetExpr(Interval(-4, 6))
assert n23cc - n23cc == SetExpr(Interval(-5, 5))
assert n23cc * n23cc == SetExpr(Interval(-6, 9))
assert n23cc / n23cc == SetExpr(Interval.open(-oo, oo))
assert n23cc + n23ro == SetExpr(Interval.Ropen(-4, 6))
assert n23cc - n23ro == SetExpr(Interval.Lopen(-5, 5))
assert n23cc * n23ro == SetExpr(Interval.Ropen(-6, 9))
assert n23cc / n23ro == SetExpr(Interval.Lopen(-oo, oo))
assert n23cc + n23lo == SetExpr(Interval.Lopen(-4, 6))
assert n23cc - n23lo == SetExpr(Interval.Ropen(-5, 5))
assert n23cc * n23lo == SetExpr(Interval(-6, 9))
assert n23cc / n23lo == SetExpr(Interval.open(-oo, oo))
assert n23cc + n23o == SetExpr(Interval.open(-4, 6))
assert n23cc - n23o == SetExpr(Interval.open(-5, 5))
assert n23cc * n23o == SetExpr(Interval.open(-6, 9))
assert n23cc / n23o == SetExpr(Interval.open(-oo, oo))
assert n23cc ** 2 == SetExpr(Interval(0, 9))
assert n23cc ** 3 == SetExpr(Interval(-8, 27))
n32cc = SetExpr(Interval(-3, 2))
n32lo = SetExpr(Interval.Lopen(-3, 2))
n32ro = SetExpr(Interval.Ropen(-3, 2))
assert n32cc * n32lo == SetExpr(Interval.Ropen(-6, 9))
assert n32cc * n32cc == SetExpr(Interval(-6, 9))
assert n32lo * n32cc == SetExpr(Interval.Ropen(-6, 9))
assert n32cc * n32ro == SetExpr(Interval(-6, 9))
assert n32lo * n32ro == SetExpr(Interval.Ropen(-6, 9))
assert n32cc / n32lo == SetExpr(Interval.Ropen(-oo, oo))
assert i12cc / n32lo == SetExpr(Interval.Ropen(-oo, oo))
assert n3n2cc ** 2 == SetExpr(Interval(4, 9))
assert n3n2cc ** 3 == SetExpr(Interval(-27, -8))
assert n23cc + i12cc == SetExpr(Interval(-1, 5))
assert n23cc - i12cc == SetExpr(Interval(-4, 2))
assert n23cc * i12cc == SetExpr(Interval(-4, 6))
assert n23cc / i12cc == SetExpr(Interval(-2, 3))
def test_SetExpr_Intersection():
x, y, z, w = symbols("x y z w")
set1 = Interval(x, y)
set2 = Interval(w, z)
inter = Intersection(set1, set2)
se = SetExpr(inter)
assert exp(se).set == Intersection(
ImageSet(Lambda(x, exp(x)), set1),
ImageSet(Lambda(x, exp(x)), set2))
assert cos(se).set == ImageSet(Lambda(x, cos(x)), inter)
def test_SetExpr_Interval_div():
# TODO: some expressions cannot be calculated due to bugs (currently
# commented):
assert SetExpr(Interval(-3, -2))/SetExpr(Interval(-2, 1)) == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(2, 3))/SetExpr(Interval(-2, 2)) == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-3, -2))/SetExpr(Interval(0, 4)) == SetExpr(Interval(-oo, -S(1)/2))
assert SetExpr(Interval(2, 4))/SetExpr(Interval(-3, 0)) == SetExpr(Interval(-oo, -S(2)/3))
assert SetExpr(Interval(2, 4))/SetExpr(Interval(0, 3)) == SetExpr(Interval(S(2)/3, oo))
#assert SetExpr(Interval(0, 1))/SetExpr(Interval(0, 1)) == SetExpr(Interval(0, oo))
#assert SetExpr(Interval(-1, 0))/SetExpr(Interval(0, 1)) == SetExpr(Interval(-oo, 0))
assert SetExpr(Interval(-1, 2))/SetExpr(Interval(-2, 2)) == SetExpr(Interval(-oo, oo))
assert 1/SetExpr(Interval(-1, 2)) == SetExpr(Union(Interval(-oo, -1), Interval(S.Half, oo)))
assert 1/SetExpr(Interval(0, 2)) == SetExpr(Interval(S(1)/2, oo))
assert (-1)/SetExpr(Interval(0, 2)) == SetExpr(Interval(-oo, -S(1)/2))
#assert 1/SetExpr(Interval(-oo, 0)) == SetExpr(Interval.open(-oo, 0))
assert 1/SetExpr(Interval(-1, 0)) == SetExpr(Interval(-oo, -1))
#assert (-2)/SetExpr(Interval(-oo, 0)) == SetExpr(Interval(0, oo))
#assert 1/SetExpr(Interval(-oo, -1)) == SetExpr(Interval(-1, 0))
#assert SetExpr(Interval(1, 2))/a == Mul(SetExpr(Interval(1, 2)), 1/a, evaluate=False)
#assert SetExpr(Interval(1, 2))/0 == SetExpr(Interval(1, 2))*zoo
#assert SetExpr(Interval(1, oo))/oo == SetExpr(Interval(0, oo))
#assert SetExpr(Interval(1, oo))/(-oo) == SetExpr(Interval(-oo, 0))
#assert SetExpr(Interval(-oo, -1))/oo == SetExpr(Interval(-oo, 0))
#assert SetExpr(Interval(-oo, -1))/(-oo) == SetExpr(Interval(0, oo))
#assert SetExpr(Interval(-oo, oo))/oo == SetExpr(Interval(-oo, oo))
#assert SetExpr(Interval(-oo, oo))/(-oo) == SetExpr(Interval(-oo, oo))
#assert SetExpr(Interval(-1, oo))/oo == SetExpr(Interval(0, oo))
#assert SetExpr(Interval(-1, oo))/(-oo) == SetExpr(Interval(-oo, 0))
#assert SetExpr(Interval(-oo, 1))/oo == SetExpr(Interval(-oo, 0))
#assert SetExpr(Interval(-oo, 1))/(-oo) == SetExpr(Interval(0, oo))
def test_SetExpr_Interval_pow():
assert SetExpr(Interval(0, 2))**2 == SetExpr(Interval(0, 4))
assert SetExpr(Interval(-1, 1))**2 == SetExpr(Interval(0, 1))
assert SetExpr(Interval(1, 2))**2 == SetExpr(Interval(1, 4))
assert SetExpr(Interval(-1, 2))**3 == SetExpr(Interval(-1, 8))
assert SetExpr(Interval(-1, 1))**0 == SetExpr(FiniteSet(1))
#assert SetExpr(Interval(1, 2))**(S(5)/2) == SetExpr(Interval(1, 4*sqrt(2)))
#assert SetExpr(Interval(-1, 2))**(S.One/3) == SetExpr(Interval(-1, 2**(S.One/3)))
#assert SetExpr(Interval(0, 2))**(S.One/2) == SetExpr(Interval(0, sqrt(2)))
#assert SetExpr(Interval(-4, 2))**(S(2)/3) == SetExpr(Interval(0, 2*2**(S.One/3)))
#assert SetExpr(Interval(-1, 5))**(S.One/2) == SetExpr(Interval(0, sqrt(5)))
#assert SetExpr(Interval(-oo, 2))**(S.One/2) == SetExpr(Interval(0, sqrt(2)))
#assert SetExpr(Interval(-2, 3))**(S(-1)/4) == SetExpr(Interval(0, oo))
assert SetExpr(Interval(1, 5))**(-2) == SetExpr(Interval(S.One/25, 1))
assert SetExpr(Interval(-1, 3))**(-2) == SetExpr(Interval(0, oo))
assert SetExpr(Interval(0, 2))**(-2) == SetExpr(Interval(S.One/4, oo))
assert SetExpr(Interval(-1, 2))**(-3) == SetExpr(Union(Interval(-oo, -1), Interval(S(1)/8, oo)))
assert SetExpr(Interval(-3, -2))**(-3) == SetExpr(Interval(S(-1)/8, -S.One/27))
assert SetExpr(Interval(-3, -2))**(-2) == SetExpr(Interval(S.One/9, S.One/4))
#assert SetExpr(Interval(0, oo))**(S.One/2) == SetExpr(Interval(0, oo))
#assert SetExpr(Interval(-oo, -1))**(S.One/3) == SetExpr(Interval(-oo, -1))
#assert SetExpr(Interval(-2, 3))**(-S.One/3) == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-oo, 0))**(-2) == SetExpr(Interval.open(0, oo))
assert SetExpr(Interval(-2, 0))**(-2) == SetExpr(Interval(S.One/4, oo))
assert SetExpr(Interval(S.One/3, S.One/2))**oo == SetExpr(FiniteSet(0))
assert SetExpr(Interval(0, S.One/2))**oo == SetExpr(FiniteSet(0))
assert SetExpr(Interval(S.One/2, 1))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(0, 1))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(2, 3))**oo == SetExpr(FiniteSet(oo))
assert SetExpr(Interval(1, 2))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(S.One/2, 3))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(-S.One/3, -S.One/4))**oo == SetExpr(FiniteSet(0))
assert SetExpr(Interval(-1, -S.One/2))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-3, -2))**oo == SetExpr(FiniteSet(-oo, oo))
assert SetExpr(Interval(-2, -1))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-2, -S.One/2))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-S.One/2, S.One/2))**oo == SetExpr(FiniteSet(0))
assert SetExpr(Interval(-S.One/2, 1))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(-S(2)/3, 2))**oo == SetExpr(Interval(0, oo))
assert SetExpr(Interval(-1, 1))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-1, S.One/2))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-1, 2))**oo == SetExpr(Interval(-oo, oo))
assert SetExpr(Interval(-2, S.One/2))**oo == SetExpr(Interval(-oo, oo))
assert (SetExpr(Interval(1, 2))**x).dummy_eq(SetExpr(ImageSet(Lambda(_d, _d**x), Interval(1, 2))))
assert SetExpr(Interval(2, 3))**(-oo) == SetExpr(FiniteSet(0))
assert SetExpr(Interval(0, 2))**(-oo) == SetExpr(Interval(0, oo))
assert (SetExpr(Interval(-1, 2))**(-oo)).dummy_eq(SetExpr(ImageSet(Lambda(_d, _d**(-oo)), Interval(-1, 2))))
|
1fe8f799c95fd03ddd384299004c8e2eddceb4e614a0526b08958fb11e4e91b8
|
import warnings
from sympy import (plot_implicit, cos, Symbol, symbols, Eq, sin, re, And, Or, exp, I,
tan, pi)
from sympy.plotting.plot import unset_show
from tempfile import NamedTemporaryFile
from sympy.utilities.pytest import skip, warns
from sympy.external import import_module
#Set plots not to show
unset_show()
def tmp_file(name=''):
return NamedTemporaryFile(suffix='.png').name
def plot_and_save(expr, *args, **kwargs):
name = kwargs.pop('name', '')
p = plot_implicit(expr, *args, **kwargs)
p.save(tmp_file(name))
# Close the plot to avoid a warning from matplotlib
p._backend.close()
def plot_implicit_tests(name):
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
#implicit plot tests
plot_and_save(Eq(y, cos(x)), (x, -5, 5), (y, -2, 2), name=name)
plot_and_save(Eq(y**2, x**3 - x), (x, -5, 5),
(y, -4, 4), name=name)
plot_and_save(y > 1 / x, (x, -5, 5),
(y, -2, 2), name=name)
plot_and_save(y < 1 / tan(x), (x, -5, 5),
(y, -2, 2), name=name)
plot_and_save(y >= 2 * sin(x) * cos(x), (x, -5, 5),
(y, -2, 2), name=name)
plot_and_save(y <= x**2, (x, -3, 3),
(y, -1, 5), name=name)
#Test all input args for plot_implicit
plot_and_save(Eq(y**2, x**3 - x))
plot_and_save(Eq(y**2, x**3 - x), adaptive=False)
plot_and_save(Eq(y**2, x**3 - x), adaptive=False, points=500)
plot_and_save(y > x, (x, -5, 5))
plot_and_save(And(y > exp(x), y > x + 2))
plot_and_save(Or(y > x, y > -x))
plot_and_save(x**2 - 1, (x, -5, 5))
plot_and_save(x**2 - 1)
plot_and_save(y > x, depth=-5)
plot_and_save(y > x, depth=5)
plot_and_save(y > cos(x), adaptive=False)
plot_and_save(y < cos(x), adaptive=False)
plot_and_save(And(y > cos(x), Or(y > x, Eq(y, x))))
plot_and_save(y - cos(pi / x))
#Test plots which cannot be rendered using the adaptive algorithm
with warns(UserWarning, match="Adaptive meshing could not be applied"):
plot_and_save(Eq(y, re(cos(x) + I*sin(x))), name=name)
plot_and_save(x**2 - 1, title='An implicit plot')
def test_line_color():
x, y = symbols('x, y')
p = plot_implicit(x**2 + y**2 - 1, line_color="green", show=False)
assert p._series[0].line_color == "green"
p = plot_implicit(x**2 + y**2 - 1, line_color='r', show=False)
assert p._series[0].line_color == "r"
def test_matplotlib():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
plot_implicit_tests('test')
test_line_color()
else:
skip("Matplotlib not the default backend")
|
fbd9cf932be97e9356a402a181489d4b2260d3b1a3838eb239f34e1597334b7f
|
from sympy import (pi, sin, cos, Symbol, Integral, Sum, sqrt, log,
oo, LambertW, I, meijerg, exp_polar, Max, Piecewise, And)
from sympy.plotting import (plot, plot_parametric, plot3d_parametric_line,
plot3d, plot3d_parametric_surface)
from sympy.plotting.plot import unset_show, plot_contour
from sympy.utilities import lambdify as lambdify_
from sympy.utilities.pytest import skip, raises, warns
from sympy.plotting.experimental_lambdify import lambdify
from sympy.external import import_module
from tempfile import NamedTemporaryFile
import os
unset_show()
# XXX: We could implement this as a context manager instead
# That would need rewriting the plot_and_save() function
# entirely
class TmpFileManager:
tmp_files = []
@classmethod
def tmp_file(cls, name=''):
cls.tmp_files.append(NamedTemporaryFile(prefix=name, suffix='.png').name)
return cls.tmp_files[-1]
@classmethod
def cleanup(cls):
for file in cls.tmp_files:
try:
os.remove(file)
except OSError:
# If the file doesn't exist, for instance, if the test failed.
pass
def plot_and_save_1(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
###
# Examples from the 'introduction' notebook
###
p = plot(x)
p = plot(x*sin(x), x*cos(x))
p.extend(p)
p[0].line_color = lambda a: a
p[1].line_color = 'b'
p.title = 'Big title'
p.xlabel = 'the x axis'
p[1].label = 'straight line'
p.legend = True
p.aspect_ratio = (1, 1)
p.xlim = (-15, 20)
p.save(tmp_file('%s_basic_options_and_colors' % name))
p._backend.close()
p.extend(plot(x + 1))
p.append(plot(x + 3, x**2)[1])
p.save(tmp_file('%s_plot_extend_append' % name))
p[2] = plot(x**2, (x, -2, 3))
p.save(tmp_file('%s_plot_setitem' % name))
p._backend.close()
p = plot(sin(x), (x, -2*pi, 4*pi))
p.save(tmp_file('%s_line_explicit' % name))
p._backend.close()
p = plot(sin(x))
p.save(tmp_file('%s_line_default_range' % name))
p._backend.close()
p = plot((x**2, (x, -5, 5)), (x**3, (x, -3, 3)))
p.save(tmp_file('%s_line_multiple_range' % name))
p._backend.close()
raises(ValueError, lambda: plot(x, y))
#Piecewise plots
p = plot(Piecewise((1, x > 0), (0, True)), (x, -1, 1))
p.save(tmp_file('%s_plot_piecewise' % name))
p._backend.close()
p = plot(Piecewise((x, x < 1), (x**2, True)), (x, -3, 3))
p.save(tmp_file('%s_plot_piecewise_2' % name))
p._backend.close()
# test issue 7471
p1 = plot(x)
p2 = plot(3)
p1.extend(p2)
p.save(tmp_file('%s_horizontal_line' % name))
p._backend.close()
# test issue 10925
f = Piecewise((-1, x < -1), (x, And(-1 <= x, x < 0)), \
(x**2, And(0 <= x, x < 1)), (x**3, x >= 1))
p = plot(f, (x, -3, 3))
p.save(tmp_file('%s_plot_piecewise_3' % name))
p._backend.close()
def plot_and_save_2(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
#parametric 2d plots.
#Single plot with default range.
plot_parametric(sin(x), cos(x)).save(tmp_file())
#Single plot with range.
p = plot_parametric(sin(x), cos(x), (x, -5, 5))
p.save(tmp_file('%s_parametric_range' % name))
p._backend.close()
#Multiple plots with same range.
p = plot_parametric((sin(x), cos(x)), (x, sin(x)))
p.save(tmp_file('%s_parametric_multiple' % name))
p._backend.close()
#Multiple plots with different ranges.
p = plot_parametric((sin(x), cos(x), (x, -3, 3)), (x, sin(x), (x, -5, 5)))
p.save(tmp_file('%s_parametric_multiple_ranges' % name))
p._backend.close()
#depth of recursion specified.
p = plot_parametric(x, sin(x), depth=13)
p.save(tmp_file('%s_recursion_depth' % name))
p._backend.close()
#No adaptive sampling.
p = plot_parametric(cos(x), sin(x), adaptive=False, nb_of_points=500)
p.save(tmp_file('%s_adaptive' % name))
p._backend.close()
#3d parametric plots
p = plot3d_parametric_line(sin(x), cos(x), x)
p.save(tmp_file('%s_3d_line' % name))
p._backend.close()
p = plot3d_parametric_line(
(sin(x), cos(x), x, (x, -5, 5)), (cos(x), sin(x), x, (x, -3, 3)))
p.save(tmp_file('%s_3d_line_multiple' % name))
p._backend.close()
p = plot3d_parametric_line(sin(x), cos(x), x, nb_of_points=30)
p.save(tmp_file('%s_3d_line_points' % name))
p._backend.close()
# 3d surface single plot.
p = plot3d(x * y)
p.save(tmp_file('%s_surface' % name))
p._backend.close()
# Multiple 3D plots with same range.
p = plot3d(-x * y, x * y, (x, -5, 5))
p.save(tmp_file('%s_surface_multiple' % name))
p._backend.close()
# Multiple 3D plots with different ranges.
p = plot3d(
(x * y, (x, -3, 3), (y, -3, 3)), (-x * y, (x, -3, 3), (y, -3, 3)))
p.save(tmp_file('%s_surface_multiple_ranges' % name))
p._backend.close()
# Single Parametric 3D plot
p = plot3d_parametric_surface(sin(x + y), cos(x - y), x - y)
p.save(tmp_file('%s_parametric_surface' % name))
p._backend.close()
# Multiple Parametric 3D plots.
p = plot3d_parametric_surface(
(x*sin(z), x*cos(z), z, (x, -5, 5), (z, -5, 5)),
(sin(x + y), cos(x - y), x - y, (x, -5, 5), (y, -5, 5)))
p.save(tmp_file('%s_parametric_surface' % name))
p._backend.close()
# Single Contour plot.
p = plot_contour(sin(x)*sin(y), (x, -5, 5), (y, -5, 5))
p.save(tmp_file('%s_contour_plot' % name))
p._backend.close()
# Multiple Contour plots with same range.
p = plot_contour(x**2 + y**2, x**3 + y**3, (x, -5, 5), (y, -5, 5))
p.save(tmp_file('%s_contour_plot' % name))
p._backend.close()
# Multiple Contour plots with different range.
p = plot_contour((x**2 + y**2, (x, -5, 5), (y, -5, 5)), (x**3 + y**3, (x, -3, 3), (y, -3, 3)))
p.save(tmp_file('%s_contour_plot' % name))
p._backend.close()
def plot_and_save_3(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
###
# Examples from the 'colors' notebook
###
p = plot(sin(x))
p[0].line_color = lambda a: a
p.save(tmp_file('%s_colors_line_arity1' % name))
p[0].line_color = lambda a, b: b
p.save(tmp_file('%s_colors_line_arity2' % name))
p._backend.close()
p = plot(x*sin(x), x*cos(x), (x, 0, 10))
p[0].line_color = lambda a: a
p.save(tmp_file('%s_colors_param_line_arity1' % name))
p[0].line_color = lambda a, b: a
p.save(tmp_file('%s_colors_param_line_arity2a' % name))
p[0].line_color = lambda a, b: b
p.save(tmp_file('%s_colors_param_line_arity2b' % name))
p._backend.close()
p = plot3d_parametric_line(sin(x) + 0.1*sin(x)*cos(7*x),
cos(x) + 0.1*cos(x)*cos(7*x),
0.1*sin(7*x),
(x, 0, 2*pi))
p[0].line_color = lambdify_(x, sin(4*x))
p.save(tmp_file('%s_colors_3d_line_arity1' % name))
p[0].line_color = lambda a, b: b
p.save(tmp_file('%s_colors_3d_line_arity2' % name))
p[0].line_color = lambda a, b, c: c
p.save(tmp_file('%s_colors_3d_line_arity3' % name))
p._backend.close()
p = plot3d(sin(x)*y, (x, 0, 6*pi), (y, -5, 5))
p[0].surface_color = lambda a: a
p.save(tmp_file('%s_colors_surface_arity1' % name))
p[0].surface_color = lambda a, b: b
p.save(tmp_file('%s_colors_surface_arity2' % name))
p[0].surface_color = lambda a, b, c: c
p.save(tmp_file('%s_colors_surface_arity3a' % name))
p[0].surface_color = lambdify_((x, y, z), sqrt((x - 3*pi)**2 + y**2))
p.save(tmp_file('%s_colors_surface_arity3b' % name))
p._backend.close()
p = plot3d_parametric_surface(x * cos(4 * y), x * sin(4 * y), y,
(x, -1, 1), (y, -1, 1))
p[0].surface_color = lambda a: a
p.save(tmp_file('%s_colors_param_surf_arity1' % name))
p[0].surface_color = lambda a, b: a*b
p.save(tmp_file('%s_colors_param_surf_arity2' % name))
p[0].surface_color = lambdify_((x, y, z), sqrt(x**2 + y**2 + z**2))
p.save(tmp_file('%s_colors_param_surf_arity3' % name))
p._backend.close()
def plot_and_save_4(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
###
# Examples from the 'advanced' notebook
###
# XXX: This raises the warning "The evaluation of the expression is
# problematic. We are trying a failback method that may still work. Please
# report this as a bug." It has to use the fallback because using evalf()
# is the only way to evaluate the integral. We should perhaps just remove
# that warning.
with warns(UserWarning, match="The evaluation of the expression is problematic"):
i = Integral(log((sin(x)**2 + 1)*sqrt(x**2 + 1)), (x, 0, y))
p = plot(i, (y, 1, 5))
p.save(tmp_file('%s_advanced_integral' % name))
p._backend.close()
def plot_and_save_5(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
s = Sum(1/x**y, (x, 1, oo))
p = plot(s, (y, 2, 10))
p.save(tmp_file('%s_advanced_inf_sum' % name))
p._backend.close()
p = plot(Sum(1/x, (x, 1, y)), (y, 2, 10), show=False)
p[0].only_integers = True
p[0].steps = True
p.save(tmp_file('%s_advanced_fin_sum' % name))
p._backend.close()
def plot_and_save_6(name):
tmp_file = TmpFileManager.tmp_file
x = Symbol('x')
y = Symbol('y')
z = Symbol('z')
###
# Test expressions that can not be translated to np and generate complex
# results.
###
plot(sin(x) + I*cos(x)).save(tmp_file())
plot(sqrt(sqrt(-x))).save(tmp_file())
plot(LambertW(x)).save(tmp_file())
plot(sqrt(LambertW(x))).save(tmp_file())
#Characteristic function of a StudentT distribution with nu=10
plot((meijerg(((1 / 2,), ()), ((5, 0, 1 / 2), ()), 5 * x**2 * exp_polar(-I*pi)/2)
+ meijerg(((1/2,), ()), ((5, 0, 1/2), ()),
5*x**2 * exp_polar(I*pi)/2)) / (48 * pi), (x, 1e-6, 1e-2)).save(tmp_file())
def test_matplotlib_1():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_1('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
def test_matplotlib_2():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_2('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
def test_matplotlib_3():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_3('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
def test_matplotlib_4():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_4('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
def test_matplotlib_5():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_5('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
def test_matplotlib_6():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
try:
plot_and_save_6('test')
finally:
# clean up
TmpFileManager.cleanup()
else:
skip("Matplotlib not the default backend")
# Tests for exception handling in experimental_lambdify
def test_experimental_lambify():
x = Symbol('x')
f = lambdify([x], Max(x, 5))
# XXX should f be tested? If f(2) is attempted, an
# error is raised because a complex produced during wrapping of the arg
# is being compared with an int.
assert Max(2, 5) == 5
assert Max(5, 7) == 7
x = Symbol('x-3')
f = lambdify([x], x + 1)
assert f(1) == 2
def test_append_issue_7140():
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if not matplotlib:
skip("Matplotlib not the default backend")
x = Symbol('x')
p1 = plot(x)
p2 = plot(x**2)
p3 = plot(x + 2)
# append a series
p2.append(p1[0])
assert len(p2._series) == 2
with raises(TypeError):
p1.append(p2)
with raises(TypeError):
p1.append(p2._series)
def test_issue_15265():
from sympy.core.sympify import sympify
from sympy.core.singleton import S
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if not matplotlib:
skip("Matplotlib not the default backend")
x = Symbol('x')
eqn = sin(x)
p = plot(eqn, xlim=(-S.Pi, S.Pi), ylim=(-1, 1))
p._backend.close()
p = plot(eqn, xlim=(-1, 1), ylim=(-S.Pi, S.Pi))
p._backend.close()
p = plot(eqn, xlim=(-1, 1), ylim=(sympify('-3.14'), sympify('3.14')))
p._backend.close()
p = plot(eqn, xlim=(sympify('-3.14'), sympify('3.14')), ylim=(-1, 1))
p._backend.close()
raises(ValueError,
lambda: plot(eqn, xlim=(-S.ImaginaryUnit, 1), ylim=(-1, 1)))
raises(ValueError,
lambda: plot(eqn, xlim=(-1, 1), ylim=(-1, S.ImaginaryUnit)))
raises(ValueError,
lambda: plot(eqn, xlim=(-S.Infinity, 1), ylim=(-1, 1)))
raises(ValueError,
lambda: plot(eqn, xlim=(-1, 1), ylim=(-1, S.Infinity)))
|
3b7eec633f52675f0a0742455bb3a12005ea7ded792e97990fe7d916a0bdc853
|
from sympy.plotting.intervalmath import interval
from sympy.utilities.pytest import raises
def test_interval():
assert (interval(1, 1) == interval(1, 1, is_valid=True)) == (True, True)
assert (interval(1, 1) == interval(1, 1, is_valid=False)) == (True, False)
assert (interval(1, 1) == interval(1, 1, is_valid=None)) == (True, None)
assert (interval(1, 1.5) == interval(1, 2)) == (None, True)
assert (interval(0, 1) == interval(2, 3)) == (False, True)
assert (interval(0, 1) == interval(1, 2)) == (None, True)
assert (interval(1, 2) != interval(1, 2)) == (False, True)
assert (interval(1, 3) != interval(2, 3)) == (None, True)
assert (interval(1, 3) != interval(-5, -3)) == (True, True)
assert (
interval(1, 3, is_valid=False) != interval(-5, -3)) == (True, False)
assert (interval(1, 3, is_valid=None) != interval(-5, 3)) == (None, None)
assert (interval(4, 4) != 4) == (False, True)
assert (interval(1, 1) == 1) == (True, True)
assert (interval(1, 3, is_valid=False) == interval(1, 3)) == (True, False)
assert (interval(1, 3, is_valid=None) == interval(1, 3)) == (True, None)
inter = interval(-5, 5)
assert (interval(inter) == interval(-5, 5)) == (True, True)
assert inter.width == 10
assert 0 in inter
assert -5 in inter
assert 5 in inter
assert interval(0, 3) in inter
assert interval(-6, 2) not in inter
assert -5.05 not in inter
assert 5.3 not in inter
interb = interval(-float('inf'), float('inf'))
assert 0 in inter
assert inter in interb
assert interval(0, float('inf')) in interb
assert interval(-float('inf'), 5) in interb
assert interval(-1e50, 1e50) in interb
assert (
-interval(-1, -2, is_valid=False) == interval(1, 2)) == (True, False)
raises(ValueError, lambda: interval(1, 2, 3))
def test_interval_add():
assert (interval(1, 2) + interval(2, 3) == interval(3, 5)) == (True, True)
assert (1 + interval(1, 2) == interval(2, 3)) == (True, True)
assert (interval(1, 2) + 1 == interval(2, 3)) == (True, True)
compare = (1 + interval(0, float('inf')) == interval(1, float('inf')))
assert compare == (True, True)
a = 1 + interval(2, 5, is_valid=False)
assert a.is_valid is False
a = 1 + interval(2, 5, is_valid=None)
assert a.is_valid is None
a = interval(2, 5, is_valid=False) + interval(3, 5, is_valid=None)
assert a.is_valid is False
a = interval(3, 5) + interval(-1, 1, is_valid=None)
assert a.is_valid is None
a = interval(2, 5, is_valid=False) + 1
assert a.is_valid is False
def test_interval_sub():
assert (interval(1, 2) - interval(1, 5) == interval(-4, 1)) == (True, True)
assert (interval(1, 2) - 1 == interval(0, 1)) == (True, True)
assert (1 - interval(1, 2) == interval(-1, 0)) == (True, True)
a = 1 - interval(1, 2, is_valid=False)
assert a.is_valid is False
a = interval(1, 4, is_valid=None) - 1
assert a.is_valid is None
a = interval(1, 3, is_valid=False) - interval(1, 3)
assert a.is_valid is False
a = interval(1, 3, is_valid=None) - interval(1, 3)
assert a.is_valid is None
def test_interval_inequality():
assert (interval(1, 2) < interval(3, 4)) == (True, True)
assert (interval(1, 2) < interval(2, 4)) == (None, True)
assert (interval(1, 2) < interval(-2, 0)) == (False, True)
assert (interval(1, 2) <= interval(2, 4)) == (True, True)
assert (interval(1, 2) <= interval(1.5, 6)) == (None, True)
assert (interval(2, 3) <= interval(1, 2)) == (None, True)
assert (interval(2, 3) <= interval(1, 1.5)) == (False, True)
assert (
interval(1, 2, is_valid=False) <= interval(-2, 0)) == (False, False)
assert (interval(1, 2, is_valid=None) <= interval(-2, 0)) == (False, None)
assert (interval(1, 2) <= 1.5) == (None, True)
assert (interval(1, 2) <= 3) == (True, True)
assert (interval(1, 2) <= 0) == (False, True)
assert (interval(5, 8) > interval(2, 3)) == (True, True)
assert (interval(2, 5) > interval(1, 3)) == (None, True)
assert (interval(2, 3) > interval(3.1, 5)) == (False, True)
assert (interval(3, 5) > 2) == (True, True)
assert (interval(3, 5) < 2) == (False, True)
assert (interval(1, 5) < 2) == (None, True)
assert (interval(1, 5) > 2) == (None, True)
assert (interval(0, 1) > 2) == (False, True)
assert (interval(1, 2) >= interval(0, 1)) == (True, True)
assert (interval(1, 2) >= interval(0, 1.5)) == (None, True)
assert (interval(1, 2) >= interval(3, 4)) == (False, True)
assert (interval(1, 2) >= 0) == (True, True)
assert (interval(1, 2) >= 1.2) == (None, True)
assert (interval(1, 2) >= 3) == (False, True)
assert (2 > interval(0, 1)) == (True, True)
a = interval(-1, 1, is_valid=False) < interval(2, 5, is_valid=None)
assert a == (True, False)
a = interval(-1, 1, is_valid=None) < interval(2, 5, is_valid=False)
assert a == (True, False)
a = interval(-1, 1, is_valid=None) < interval(2, 5, is_valid=None)
assert a == (True, None)
a = interval(-1, 1, is_valid=False) > interval(-5, -2, is_valid=None)
assert a == (True, False)
a = interval(-1, 1, is_valid=None) > interval(-5, -2, is_valid=False)
assert a == (True, False)
a = interval(-1, 1, is_valid=None) > interval(-5, -2, is_valid=None)
assert a == (True, None)
def test_interval_mul():
assert (
interval(1, 5) * interval(2, 10) == interval(2, 50)) == (True, True)
a = interval(-1, 1) * interval(2, 10) == interval(-10, 10)
assert a == (True, True)
a = interval(-1, 1) * interval(-5, 3) == interval(-5, 5)
assert a == (True, True)
assert (interval(1, 3) * 2 == interval(2, 6)) == (True, True)
assert (3 * interval(-1, 2) == interval(-3, 6)) == (True, True)
a = 3 * interval(1, 2, is_valid=False)
assert a.is_valid is False
a = 3 * interval(1, 2, is_valid=None)
assert a.is_valid is None
a = interval(1, 5, is_valid=False) * interval(1, 2, is_valid=None)
assert a.is_valid is False
def test_interval_div():
div = interval(1, 2, is_valid=False) / 3
assert div == interval(-float('inf'), float('inf'), is_valid=False)
div = interval(1, 2, is_valid=None) / 3
assert div == interval(-float('inf'), float('inf'), is_valid=None)
div = 3 / interval(1, 2, is_valid=None)
assert div == interval(-float('inf'), float('inf'), is_valid=None)
a = interval(1, 2) / 0
assert a.is_valid is False
a = interval(0.5, 1) / interval(-1, 0)
assert a.is_valid is None
a = interval(0, 1) / interval(0, 1)
assert a.is_valid is None
a = interval(-1, 1) / interval(-1, 1)
assert a.is_valid is None
a = interval(-1, 2) / interval(0.5, 1) == interval(-2.0, 4.0)
assert a == (True, True)
a = interval(0, 1) / interval(0.5, 1) == interval(0.0, 2.0)
assert a == (True, True)
a = interval(-1, 0) / interval(0.5, 1) == interval(-2.0, 0.0)
assert a == (True, True)
a = interval(-0.5, -0.25) / interval(0.5, 1) == interval(-1.0, -0.25)
assert a == (True, True)
a = interval(0.5, 1) / interval(0.5, 1) == interval(0.5, 2.0)
assert a == (True, True)
a = interval(0.5, 4) / interval(0.5, 1) == interval(0.5, 8.0)
assert a == (True, True)
a = interval(-1, -0.5) / interval(0.5, 1) == interval(-2.0, -0.5)
assert a == (True, True)
a = interval(-4, -0.5) / interval(0.5, 1) == interval(-8.0, -0.5)
assert a == (True, True)
a = interval(-1, 2) / interval(-2, -0.5) == interval(-4.0, 2.0)
assert a == (True, True)
a = interval(0, 1) / interval(-2, -0.5) == interval(-2.0, 0.0)
assert a == (True, True)
a = interval(-1, 0) / interval(-2, -0.5) == interval(0.0, 2.0)
assert a == (True, True)
a = interval(-0.5, -0.25) / interval(-2, -0.5) == interval(0.125, 1.0)
assert a == (True, True)
a = interval(0.5, 1) / interval(-2, -0.5) == interval(-2.0, -0.25)
assert a == (True, True)
a = interval(0.5, 4) / interval(-2, -0.5) == interval(-8.0, -0.25)
assert a == (True, True)
a = interval(-1, -0.5) / interval(-2, -0.5) == interval(0.25, 2.0)
assert a == (True, True)
a = interval(-4, -0.5) / interval(-2, -0.5) == interval(0.25, 8.0)
assert a == (True, True)
a = interval(-5, 5, is_valid=False) / 2
assert a.is_valid is False
def test_hashable():
'''
test that interval objects are hashable.
this is required in order to be able to put them into the cache, which
appears to be necessary for plotting in py3k. For details, see:
https://github.com/sympy/sympy/pull/2101
https://github.com/sympy/sympy/issues/6533
'''
hash(interval(1, 1))
hash(interval(1, 1, is_valid=True))
hash(interval(-4, -0.5))
hash(interval(-2, -0.5))
hash(interval(0.25, 8.0))
|
032c6d6eba4cb3d68759cf4811a9344e7d0574c189e5c93cc6cd9ab66bfad531
|
from sympy.external import import_module
from sympy.plotting.intervalmath import (
Abs, acos, acosh, And, asin, asinh, atan, atanh, ceil, cos, cosh,
exp, floor, imax, imin, interval, log, log10, Or, sin, sinh, sqrt,
tan, tanh,
)
np = import_module('numpy')
if not np:
disabled = True
#requires Numpy. Hence included in interval_functions
def test_interval_pow():
a = 2**interval(1, 2) == interval(2, 4)
assert a == (True, True)
a = interval(1, 2)**interval(1, 2) == interval(1, 4)
assert a == (True, True)
a = interval(-1, 1)**interval(0.5, 2)
assert a.is_valid is None
a = interval(-2, -1) ** interval(1, 2)
assert a.is_valid is False
a = interval(-2, -1) ** (1 / 2)
assert a.is_valid is False
a = interval(-1, 1)**(1 / 2)
assert a.is_valid is None
a = interval(-1, 1)**(1 / 3) == interval(-1, 1)
assert a == (True, True)
a = interval(-1, 1)**2 == interval(0, 1)
assert a == (True, True)
a = interval(-1, 1) ** (1 / 29) == interval(-1, 1)
assert a == (True, True)
a = -2**interval(1, 1) == interval(-2, -2)
assert a == (True, True)
a = interval(1, 2, is_valid=False)**2
assert a.is_valid is False
a = (-3)**interval(1, 2)
assert a.is_valid is False
a = (-4)**interval(0.5, 0.5)
assert a.is_valid is False
assert ((-3)**interval(1, 1) == interval(-3, -3)) == (True, True)
a = interval(8, 64)**(2 / 3)
assert abs(a.start - 4) < 1e-10 # eps
assert abs(a.end - 16) < 1e-10
a = interval(-8, 64)**(2 / 3)
assert abs(a.start - 4) < 1e-10 # eps
assert abs(a.end - 16) < 1e-10
def test_exp():
a = exp(interval(-np.inf, 0))
assert a.start == np.exp(-np.inf)
assert a.end == np.exp(0)
a = exp(interval(1, 2))
assert a.start == np.exp(1)
assert a.end == np.exp(2)
a = exp(1)
assert a.start == np.exp(1)
assert a.end == np.exp(1)
def test_log():
a = log(interval(1, 2))
assert a.start == 0
assert a.end == np.log(2)
a = log(interval(-1, 1))
assert a.is_valid is None
a = log(interval(-3, -1))
assert a.is_valid is False
a = log(-3)
assert a.is_valid is False
a = log(2)
assert a.start == np.log(2)
assert a.end == np.log(2)
def test_log10():
a = log10(interval(1, 2))
assert a.start == 0
assert a.end == np.log10(2)
a = log10(interval(-1, 1))
assert a.is_valid is None
a = log10(interval(-3, -1))
assert a.is_valid is False
a = log10(-3)
assert a.is_valid is False
a = log10(2)
assert a.start == np.log10(2)
assert a.end == np.log10(2)
def test_atan():
a = atan(interval(0, 1))
assert a.start == np.arctan(0)
assert a.end == np.arctan(1)
a = atan(1)
assert a.start == np.arctan(1)
assert a.end == np.arctan(1)
def test_sin():
a = sin(interval(0, np.pi / 4))
assert a.start == np.sin(0)
assert a.end == np.sin(np.pi / 4)
a = sin(interval(-np.pi / 4, np.pi / 4))
assert a.start == np.sin(-np.pi / 4)
assert a.end == np.sin(np.pi / 4)
a = sin(interval(np.pi / 4, 3 * np.pi / 4))
assert a.start == np.sin(np.pi / 4)
assert a.end == 1
a = sin(interval(7 * np.pi / 6, 7 * np.pi / 4))
assert a.start == -1
assert a.end == np.sin(7 * np.pi / 6)
a = sin(interval(0, 3 * np.pi))
assert a.start == -1
assert a.end == 1
a = sin(interval(np.pi / 3, 7 * np.pi / 4))
assert a.start == -1
assert a.end == 1
a = sin(np.pi / 4)
assert a.start == np.sin(np.pi / 4)
assert a.end == np.sin(np.pi / 4)
a = sin(interval(1, 2, is_valid=False))
assert a.is_valid is False
def test_cos():
a = cos(interval(0, np.pi / 4))
assert a.start == np.cos(np.pi / 4)
assert a.end == 1
a = cos(interval(-np.pi / 4, np.pi / 4))
assert a.start == np.cos(-np.pi / 4)
assert a.end == 1
a = cos(interval(np.pi / 4, 3 * np.pi / 4))
assert a.start == np.cos(3 * np.pi / 4)
assert a.end == np.cos(np.pi / 4)
a = cos(interval(3 * np.pi / 4, 5 * np.pi / 4))
assert a.start == -1
assert a.end == np.cos(3 * np.pi / 4)
a = cos(interval(0, 3 * np.pi))
assert a.start == -1
assert a.end == 1
a = cos(interval(- np.pi / 3, 5 * np.pi / 4))
assert a.start == -1
assert a.end == 1
a = cos(interval(1, 2, is_valid=False))
assert a.is_valid is False
def test_tan():
a = tan(interval(0, np.pi / 4))
assert a.start == 0
# must match lib_interval definition of tan:
assert a.end == np.sin(np.pi / 4)/np.cos(np.pi / 4)
a = tan(interval(np.pi / 4, 3 * np.pi / 4))
#discontinuity
assert a.is_valid is None
def test_sqrt():
a = sqrt(interval(1, 4))
assert a.start == 1
assert a.end == 2
a = sqrt(interval(0.01, 1))
assert a.start == np.sqrt(0.01)
assert a.end == 1
a = sqrt(interval(-1, 1))
assert a.is_valid is None
a = sqrt(interval(-3, -1))
assert a.is_valid is False
a = sqrt(4)
assert (a == interval(2, 2)) == (True, True)
a = sqrt(-3)
assert a.is_valid is False
def test_imin():
a = imin(interval(1, 3), interval(2, 5), interval(-1, 3))
assert a.start == -1
assert a.end == 3
a = imin(-2, interval(1, 4))
assert a.start == -2
assert a.end == -2
a = imin(5, interval(3, 4), interval(-2, 2, is_valid=False))
assert a.start == 3
assert a.end == 4
def test_imax():
a = imax(interval(-2, 2), interval(2, 7), interval(-3, 9))
assert a.start == 2
assert a.end == 9
a = imax(8, interval(1, 4))
assert a.start == 8
assert a.end == 8
a = imax(interval(1, 2), interval(3, 4), interval(-2, 2, is_valid=False))
assert a.start == 3
assert a.end == 4
def test_sinh():
a = sinh(interval(-1, 1))
assert a.start == np.sinh(-1)
assert a.end == np.sinh(1)
a = sinh(1)
assert a.start == np.sinh(1)
assert a.end == np.sinh(1)
def test_cosh():
a = cosh(interval(1, 2))
assert a.start == np.cosh(1)
assert a.end == np.cosh(2)
a = cosh(interval(-2, -1))
assert a.start == np.cosh(-1)
assert a.end == np.cosh(-2)
a = cosh(interval(-2, 1))
assert a.start == 1
assert a.end == np.cosh(-2)
a = cosh(1)
assert a.start == np.cosh(1)
assert a.end == np.cosh(1)
def test_tanh():
a = tanh(interval(-3, 3))
assert a.start == np.tanh(-3)
assert a.end == np.tanh(3)
a = tanh(3)
assert a.start == np.tanh(3)
assert a.end == np.tanh(3)
def test_asin():
a = asin(interval(-0.5, 0.5))
assert a.start == np.arcsin(-0.5)
assert a.end == np.arcsin(0.5)
a = asin(interval(-1.5, 1.5))
assert a.is_valid is None
a = asin(interval(-2, -1.5))
assert a.is_valid is False
a = asin(interval(0, 2))
assert a.is_valid is None
a = asin(interval(2, 5))
assert a.is_valid is False
a = asin(0.5)
assert a.start == np.arcsin(0.5)
assert a.end == np.arcsin(0.5)
a = asin(1.5)
assert a.is_valid is False
def test_acos():
a = acos(interval(-0.5, 0.5))
assert a.start == np.arccos(0.5)
assert a.end == np.arccos(-0.5)
a = acos(interval(-1.5, 1.5))
assert a.is_valid is None
a = acos(interval(-2, -1.5))
assert a.is_valid is False
a = acos(interval(0, 2))
assert a.is_valid is None
a = acos(interval(2, 5))
assert a.is_valid is False
a = acos(0.5)
assert a.start == np.arccos(0.5)
assert a.end == np.arccos(0.5)
a = acos(1.5)
assert a.is_valid is False
def test_ceil():
a = ceil(interval(0.2, 0.5))
assert a.start == 1
assert a.end == 1
a = ceil(interval(0.5, 1.5))
assert a.start == 1
assert a.end == 2
assert a.is_valid is None
a = ceil(interval(-5, 5))
assert a.is_valid is None
a = ceil(5.4)
assert a.start == 6
assert a.end == 6
def test_floor():
a = floor(interval(0.2, 0.5))
assert a.start == 0
assert a.end == 0
a = floor(interval(0.5, 1.5))
assert a.start == 0
assert a.end == 1
assert a.is_valid is None
a = floor(interval(-5, 5))
assert a.is_valid is None
a = floor(5.4)
assert a.start == 5
assert a.end == 5
def test_asinh():
a = asinh(interval(1, 2))
assert a.start == np.arcsinh(1)
assert a.end == np.arcsinh(2)
a = asinh(0.5)
assert a.start == np.arcsinh(0.5)
assert a.end == np.arcsinh(0.5)
def test_acosh():
a = acosh(interval(3, 5))
assert a.start == np.arccosh(3)
assert a.end == np.arccosh(5)
a = acosh(interval(0, 3))
assert a.is_valid is None
a = acosh(interval(-3, 0.5))
assert a.is_valid is False
a = acosh(0.5)
assert a.is_valid is False
a = acosh(2)
assert a.start == np.arccosh(2)
assert a.end == np.arccosh(2)
def test_atanh():
a = atanh(interval(-0.5, 0.5))
assert a.start == np.arctanh(-0.5)
assert a.end == np.arctanh(0.5)
a = atanh(interval(0, 3))
assert a.is_valid is None
a = atanh(interval(-3, -2))
assert a.is_valid is False
a = atanh(0.5)
assert a.start == np.arctanh(0.5)
assert a.end == np.arctanh(0.5)
a = atanh(1.5)
assert a.is_valid is False
def test_Abs():
assert (Abs(interval(-0.5, 0.5)) == interval(0, 0.5)) == (True, True)
assert (Abs(interval(-3, -2)) == interval(2, 3)) == (True, True)
assert (Abs(-3) == interval(3, 3)) == (True, True)
def test_And():
args = [(True, True), (True, False), (True, None)]
assert And(*args) == (True, False)
args = [(False, True), (None, None), (True, True)]
assert And(*args) == (False, None)
def test_Or():
args = [(True, True), (True, False), (False, None)]
assert Or(*args) == (True, True)
args = [(None, None), (False, None), (False, False)]
assert Or(*args) == (None, None)
|
2de8e36bc46d2e4c00f748f03e7e0fbdd76f8266cadbd48852b3be8227362dd4
|
# -*- coding: utf-8 -*-
from __future__ import print_function, division, absolute_import
import os
from itertools import chain
import json
import sys
import warnings
import pytest
from sympy.utilities.runtests import setup_pprint, _get_doctest_blacklist
durations_path = os.path.join(os.path.dirname(__file__), '.ci', 'durations.json')
blacklist_path = os.path.join(os.path.dirname(__file__), '.ci', 'blacklisted.json')
# Collecting tests from rubi_tests under pytest leads to errors even if the
# tests will be skipped.
collect_ignore = ["sympy/integrals/rubi"] + _get_doctest_blacklist()
if sys.version_info < (3,):
collect_ignore.append('doc/src/gotchas.rst')
# Set up printing for doctests
setup_pprint()
sys.__displayhook__ = sys.displayhook
#from sympy import pprint_use_unicode
#pprint_use_unicode(False)
def _mk_group(group_dict):
return list(chain(*[[k+'::'+v for v in files] for k, files in group_dict.items()]))
if os.path.exists(durations_path):
veryslow_group, slow_group = [_mk_group(group_dict) for group_dict in json.loads(open(durations_path, 'rt').read())]
else:
# warnings in conftest has issues: https://github.com/pytest-dev/pytest/issues/2891
warnings.warn("conftest.py:22: Could not find %s, --quickcheck and --veryquickcheck will have no effect.\n" % durations_path)
veryslow_group, slow_group = [], []
if os.path.exists(blacklist_path):
blacklist_group = _mk_group(json.loads(open(blacklist_path, 'rt').read()))
else:
warnings.warn("conftest.py:28: Could not find %s, no tests will be skipped due to blacklisting\n" % blacklist_path)
blacklist_group = []
def pytest_addoption(parser):
parser.addoption("--quickcheck", dest="runquick", action="store_true",
help="Skip very slow tests (see ./ci/parse_durations_log.py)")
parser.addoption("--veryquickcheck", dest="runveryquick", action="store_true",
help="Skip slow & very slow (see ./ci/parse_durations_log.py)")
def pytest_configure(config):
# register an additional marker
config.addinivalue_line("markers", "slow: manually marked test as slow (use .ci/durations.json instead)")
config.addinivalue_line("markers", "quickcheck: skip very slow tests")
config.addinivalue_line("markers", "veryquickcheck: skip slow & very slow tests")
def pytest_runtest_setup(item):
if isinstance(item, pytest.Function):
if item.nodeid in veryslow_group and (item.config.getvalue("runquick") or
item.config.getvalue("runveryquick")):
pytest.skip("very slow test, skipping since --quickcheck or --veryquickcheck was passed.")
return
if item.nodeid in slow_group and item.config.getvalue("runveryquick"):
pytest.skip("slow test, skipping since --veryquickcheck was passed.")
return
if item.nodeid in blacklist_group:
pytest.skip("blacklisted test, see %s" % blacklist_path)
return
|
187f071433e3c576d881b18a2cc72ab96487dbbc9f6f6497eeca140b7fc46881
|
"""
Main Random Variables Module
Defines abstract random variable type.
Contains interfaces for probability space object (PSpace) as well as standard
operators, P, E, sample, density, where
See Also
========
sympy.stats.crv
sympy.stats.frv
sympy.stats.rv_interface
"""
from __future__ import print_function, division
from sympy import (Basic, S, Expr, Symbol, Tuple, And, Add, Eq, lambdify,
Equality, Lambda, sympify, Dummy, Ne, KroneckerDelta,
DiracDelta, Mul, Indexed)
from sympy.core.relational import Relational
from sympy.core.compatibility import string_types
from sympy.logic.boolalg import Boolean
from sympy.solvers.solveset import solveset
from sympy.sets.sets import FiniteSet, ProductSet, Intersection
from sympy.abc import x
class RandomDomain(Basic):
"""
Represents a set of variables and the values which they can take
See Also
========
sympy.stats.crv.ContinuousDomain
sympy.stats.frv.FiniteDomain
"""
is_ProductDomain = False
is_Finite = False
is_Continuous = False
is_Discrete = False
def __new__(cls, symbols, *args):
symbols = FiniteSet(*symbols)
return Basic.__new__(cls, symbols, *args)
@property
def symbols(self):
return self.args[0]
@property
def set(self):
return self.args[1]
def __contains__(self, other):
raise NotImplementedError()
def compute_expectation(self, expr):
raise NotImplementedError()
class SingleDomain(RandomDomain):
"""
A single variable and its domain
See Also
========
sympy.stats.crv.SingleContinuousDomain
sympy.stats.frv.SingleFiniteDomain
"""
def __new__(cls, symbol, set):
assert symbol.is_Symbol
return Basic.__new__(cls, symbol, set)
@property
def symbol(self):
return self.args[0]
@property
def symbols(self):
return FiniteSet(self.symbol)
def __contains__(self, other):
if len(other) != 1:
return False
sym, val = tuple(other)[0]
return self.symbol == sym and val in self.set
class ConditionalDomain(RandomDomain):
"""
A RandomDomain with an attached condition
See Also
========
sympy.stats.crv.ConditionalContinuousDomain
sympy.stats.frv.ConditionalFiniteDomain
"""
def __new__(cls, fulldomain, condition):
condition = condition.xreplace(dict((rs, rs.symbol)
for rs in random_symbols(condition)))
return Basic.__new__(cls, fulldomain, condition)
@property
def symbols(self):
return self.fulldomain.symbols
@property
def fulldomain(self):
return self.args[0]
@property
def condition(self):
return self.args[1]
@property
def set(self):
raise NotImplementedError("Set of Conditional Domain not Implemented")
def as_boolean(self):
return And(self.fulldomain.as_boolean(), self.condition)
class PSpace(Basic):
"""
A Probability Space
Probability Spaces encode processes that equal different values
probabilistically. These underly Random Symbols which occur in SymPy
expressions and contain the mechanics to evaluate statistical statements.
See Also
========
sympy.stats.crv.ContinuousPSpace
sympy.stats.frv.FinitePSpace
"""
is_Finite = None
is_Continuous = None
is_Discrete = None
is_real = None
@property
def domain(self):
return self.args[0]
@property
def density(self):
return self.args[1]
@property
def values(self):
return frozenset(RandomSymbol(sym, self) for sym in self.symbols)
@property
def symbols(self):
return self.domain.symbols
def where(self, condition):
raise NotImplementedError()
def compute_density(self, expr):
raise NotImplementedError()
def sample(self):
raise NotImplementedError()
def probability(self, condition):
raise NotImplementedError()
def compute_expectation(self, expr):
raise NotImplementedError()
class SinglePSpace(PSpace):
"""
Represents the probabilities of a set of random events that can be
attributed to a single variable/symbol.
"""
def __new__(cls, s, distribution):
if isinstance(s, string_types):
s = Symbol(s)
if not isinstance(s, Symbol):
raise TypeError("s should have been string or Symbol")
return Basic.__new__(cls, s, distribution)
@property
def value(self):
return RandomSymbol(self.symbol, self)
@property
def symbol(self):
return self.args[0]
@property
def distribution(self):
return self.args[1]
@property
def pdf(self):
return self.distribution.pdf(self.symbol)
class RandomSymbol(Expr):
"""
Random Symbols represent ProbabilitySpaces in SymPy Expressions
In principle they can take on any value that their symbol can take on
within the associated PSpace with probability determined by the PSpace
Density.
Random Symbols contain pspace and symbol properties.
The pspace property points to the represented Probability Space
The symbol is a standard SymPy Symbol that is used in that probability space
for example in defining a density.
You can form normal SymPy expressions using RandomSymbols and operate on
those expressions with the Functions
E - Expectation of a random expression
P - Probability of a condition
density - Probability Density of an expression
given - A new random expression (with new random symbols) given a condition
An object of the RandomSymbol type should almost never be created by the
user. They tend to be created instead by the PSpace class's value method.
Traditionally a user doesn't even do this but instead calls one of the
convenience functions Normal, Exponential, Coin, Die, FiniteRV, etc....
"""
def __new__(cls, symbol, pspace=None):
from sympy.stats.joint_rv import JointRandomSymbol
if pspace is None:
# Allow single arg, representing pspace == PSpace()
pspace = PSpace()
if not isinstance(symbol, Symbol):
raise TypeError("symbol should be of type Symbol")
if not isinstance(pspace, PSpace):
raise TypeError("pspace variable should be of type PSpace")
if cls == JointRandomSymbol and isinstance(pspace, SinglePSpace):
cls = RandomSymbol
return Basic.__new__(cls, symbol, pspace)
is_finite = True
is_symbol = True
is_Atom = True
_diff_wrt = True
pspace = property(lambda self: self.args[1])
symbol = property(lambda self: self.args[0])
name = property(lambda self: self.symbol.name)
def _eval_is_positive(self):
return self.symbol.is_positive
def _eval_is_integer(self):
return self.symbol.is_integer
def _eval_is_real(self):
return self.symbol.is_real or self.pspace.is_real
@property
def is_commutative(self):
return self.symbol.is_commutative
def _hashable_content(self):
return self.pspace, self.symbol
@property
def free_symbols(self):
return {self}
class ProductPSpace(PSpace):
"""
Abstract class for representing probability spaces with multiple random
variables.
See Also
========
sympy.stats.rv.IndependentProductPSpace
sympy.stats.joint_rv.JointPSpace
"""
pass
class IndependentProductPSpace(ProductPSpace):
"""
A probability space resulting from the merger of two independent probability
spaces.
Often created using the function, pspace
"""
def __new__(cls, *spaces):
rs_space_dict = {}
for space in spaces:
for value in space.values:
rs_space_dict[value] = space
symbols = FiniteSet(*[val.symbol for val in rs_space_dict.keys()])
# Overlapping symbols
from sympy.stats.joint_rv import MarginalDistribution, CompoundDistribution
if len(symbols) < sum(len(space.symbols) for space in spaces if not
isinstance(space.distribution, (
CompoundDistribution, MarginalDistribution))):
raise ValueError("Overlapping Random Variables")
if all(space.is_Finite for space in spaces):
from sympy.stats.frv import ProductFinitePSpace
cls = ProductFinitePSpace
obj = Basic.__new__(cls, *FiniteSet(*spaces))
return obj
@property
def pdf(self):
p = Mul(*[space.pdf for space in self.spaces])
return p.subs(dict((rv, rv.symbol) for rv in self.values))
@property
def rs_space_dict(self):
d = {}
for space in self.spaces:
for value in space.values:
d[value] = space
return d
@property
def symbols(self):
return FiniteSet(*[val.symbol for val in self.rs_space_dict.keys()])
@property
def spaces(self):
return FiniteSet(*self.args)
@property
def values(self):
return sumsets(space.values for space in self.spaces)
def compute_expectation(self, expr, rvs=None, evaluate=False, **kwargs):
rvs = rvs or self.values
rvs = frozenset(rvs)
for space in self.spaces:
expr = space.compute_expectation(expr, rvs & space.values, evaluate=False, **kwargs)
if evaluate and hasattr(expr, 'doit'):
return expr.doit(**kwargs)
return expr
@property
def domain(self):
return ProductDomain(*[space.domain for space in self.spaces])
@property
def density(self):
raise NotImplementedError("Density not available for ProductSpaces")
def sample(self):
return dict([(k, v) for space in self.spaces
for k, v in space.sample().items()])
def probability(self, condition, **kwargs):
cond_inv = False
if isinstance(condition, Ne):
condition = Eq(condition.args[0], condition.args[1])
cond_inv = True
expr = condition.lhs - condition.rhs
rvs = random_symbols(expr)
z = Dummy('z', real=True, Finite=True)
dens = self.compute_density(expr)
if any([pspace(rv).is_Continuous for rv in rvs]):
from sympy.stats.crv import (ContinuousDistributionHandmade,
SingleContinuousPSpace)
if expr in self.values:
# Marginalize all other random symbols out of the density
randomsymbols = tuple(set(self.values) - frozenset([expr]))
symbols = tuple(rs.symbol for rs in randomsymbols)
pdf = self.domain.integrate(self.pdf, symbols, **kwargs)
return Lambda(expr.symbol, pdf)
dens = ContinuousDistributionHandmade(dens)
space = SingleContinuousPSpace(z, dens)
result = space.probability(condition.__class__(space.value, 0))
else:
from sympy.stats.drv import (DiscreteDistributionHandmade,
SingleDiscretePSpace)
dens = DiscreteDistributionHandmade(dens)
space = SingleDiscretePSpace(z, dens)
result = space.probability(condition.__class__(space.value, 0))
return result if not cond_inv else S.One - result
def compute_density(self, expr, **kwargs):
z = Dummy('z', real=True, finite=True)
rvs = random_symbols(expr)
if any(pspace(rv).is_Continuous for rv in rvs):
expr = self.compute_expectation(DiracDelta(expr - z),
**kwargs)
else:
expr = self.compute_expectation(KroneckerDelta(expr, z),
**kwargs)
return Lambda(z, expr)
def compute_cdf(self, expr, **kwargs):
raise ValueError("CDF not well defined on multivariate expressions")
def conditional_space(self, condition, normalize=True, **kwargs):
rvs = random_symbols(condition)
condition = condition.xreplace(dict((rv, rv.symbol) for rv in self.values))
if any([pspace(rv).is_Continuous for rv in rvs]):
from sympy.stats.crv import (ConditionalContinuousDomain,
ContinuousPSpace)
space = ContinuousPSpace
domain = ConditionalContinuousDomain(self.domain, condition)
elif any([pspace(rv).is_Discrete for rv in rvs]):
from sympy.stats.drv import (ConditionalDiscreteDomain,
DiscretePSpace)
space = DiscretePSpace
domain = ConditionalDiscreteDomain(self.domain, condition)
elif all([pspace(rv).is_Finite for rv in rvs]):
from sympy.stats.frv import FinitePSpace
return FinitePSpace.conditional_space(self, condition)
if normalize:
replacement = {rv: Dummy(str(rv)) for rv in self.symbols}
norm = domain.compute_expectation(self.pdf, **kwargs)
pdf = self.pdf / norm.xreplace(replacement)
density = Lambda(domain.symbols, pdf)
return space(domain, density)
class ProductDomain(RandomDomain):
"""
A domain resulting from the merger of two independent domains
See Also
========
sympy.stats.crv.ProductContinuousDomain
sympy.stats.frv.ProductFiniteDomain
"""
is_ProductDomain = True
def __new__(cls, *domains):
symbols = sumsets([domain.symbols for domain in domains])
# Flatten any product of products
domains2 = []
for domain in domains:
if not domain.is_ProductDomain:
domains2.append(domain)
else:
domains2.extend(domain.domains)
domains2 = FiniteSet(*domains2)
if all(domain.is_Finite for domain in domains2):
from sympy.stats.frv import ProductFiniteDomain
cls = ProductFiniteDomain
if all(domain.is_Continuous for domain in domains2):
from sympy.stats.crv import ProductContinuousDomain
cls = ProductContinuousDomain
if all(domain.is_Discrete for domain in domains2):
from sympy.stats.drv import ProductDiscreteDomain
cls = ProductDiscreteDomain
return Basic.__new__(cls, *domains2)
@property
def sym_domain_dict(self):
return dict((symbol, domain) for domain in self.domains
for symbol in domain.symbols)
@property
def symbols(self):
return FiniteSet(*[sym for domain in self.domains
for sym in domain.symbols])
@property
def domains(self):
return self.args
@property
def set(self):
return ProductSet(domain.set for domain in self.domains)
def __contains__(self, other):
# Split event into each subdomain
for domain in self.domains:
# Collect the parts of this event which associate to this domain
elem = frozenset([item for item in other
if sympify(domain.symbols.contains(item[0]))
is S.true])
# Test this sub-event
if elem not in domain:
return False
# All subevents passed
return True
def as_boolean(self):
return And(*[domain.as_boolean() for domain in self.domains])
def random_symbols(expr):
"""
Returns all RandomSymbols within a SymPy Expression.
"""
try:
return list(expr.atoms(RandomSymbol))
except AttributeError:
return []
def pspace(expr):
"""
Returns the underlying Probability Space of a random expression.
For internal use.
Examples
========
>>> from sympy.stats import pspace, Normal
>>> from sympy.stats.rv import IndependentProductPSpace
>>> X = Normal('X', 0, 1)
>>> pspace(2*X + 1) == X.pspace
True
"""
expr = sympify(expr)
if isinstance(expr, RandomSymbol) and expr.pspace != None:
return expr.pspace
rvs = random_symbols(expr)
if not rvs:
raise ValueError("Expression containing Random Variable expected, not %s" % (expr))
# If only one space present
if all(rv.pspace == rvs[0].pspace for rv in rvs):
return rvs[0].pspace
# Otherwise make a product space
return IndependentProductPSpace(*[rv.pspace for rv in rvs])
def sumsets(sets):
"""
Union of sets
"""
return frozenset().union(*sets)
def rs_swap(a, b):
"""
Build a dictionary to swap RandomSymbols based on their underlying symbol.
i.e.
if ``X = ('x', pspace1)``
and ``Y = ('x', pspace2)``
then ``X`` and ``Y`` match and the key, value pair
``{X:Y}`` will appear in the result
Inputs: collections a and b of random variables which share common symbols
Output: dict mapping RVs in a to RVs in b
"""
d = {}
for rsa in a:
d[rsa] = [rsb for rsb in b if rsa.symbol == rsb.symbol][0]
return d
def given(expr, condition=None, **kwargs):
r""" Conditional Random Expression
From a random expression and a condition on that expression creates a new
probability space from the condition and returns the same expression on that
conditional probability space.
Examples
========
>>> from sympy.stats import given, density, Die
>>> X = Die('X', 6)
>>> Y = given(X, X > 3)
>>> density(Y).dict
{4: 1/3, 5: 1/3, 6: 1/3}
Following convention, if the condition is a random symbol then that symbol
is considered fixed.
>>> from sympy.stats import Normal
>>> from sympy import pprint
>>> from sympy.abc import z
>>> X = Normal('X', 0, 1)
>>> Y = Normal('Y', 0, 1)
>>> pprint(density(X + Y, Y)(z), use_unicode=False)
2
-(-Y + z)
-----------
___ 2
\/ 2 *e
------------------
____
2*\/ pi
"""
if not random_symbols(condition) or pspace_independent(expr, condition):
return expr
if isinstance(condition, RandomSymbol):
condition = Eq(condition, condition.symbol)
condsymbols = random_symbols(condition)
if (isinstance(condition, Equality) and len(condsymbols) == 1 and
not isinstance(pspace(expr).domain, ConditionalDomain)):
rv = tuple(condsymbols)[0]
results = solveset(condition, rv)
if isinstance(results, Intersection) and S.Reals in results.args:
results = list(results.args[1])
sums = 0
for res in results:
temp = expr.subs(rv, res)
if temp == True:
return True
if temp != False:
sums += expr.subs(rv, res)
if sums == 0:
return False
return sums
# Get full probability space of both the expression and the condition
fullspace = pspace(Tuple(expr, condition))
# Build new space given the condition
space = fullspace.conditional_space(condition, **kwargs)
# Dictionary to swap out RandomSymbols in expr with new RandomSymbols
# That point to the new conditional space
swapdict = rs_swap(fullspace.values, space.values)
# Swap random variables in the expression
expr = expr.xreplace(swapdict)
return expr
def expectation(expr, condition=None, numsamples=None, evaluate=True, **kwargs):
"""
Returns the expected value of a random expression
Parameters
==========
expr : Expr containing RandomSymbols
The expression of which you want to compute the expectation value
given : Expr containing RandomSymbols
A conditional expression. E(X, X>0) is expectation of X given X > 0
numsamples : int
Enables sampling and approximates the expectation with this many samples
evalf : Bool (defaults to True)
If sampling return a number rather than a complex expression
evaluate : Bool (defaults to True)
In case of continuous systems return unevaluated integral
Examples
========
>>> from sympy.stats import E, Die
>>> X = Die('X', 6)
>>> E(X)
7/2
>>> E(2*X + 1)
8
>>> E(X, X > 3) # Expectation of X given that it is above 3
5
"""
if not random_symbols(expr): # expr isn't random?
return expr
if numsamples: # Computing by monte carlo sampling?
return sampling_E(expr, condition, numsamples=numsamples)
# Create new expr and recompute E
if condition is not None: # If there is a condition
return expectation(given(expr, condition), evaluate=evaluate)
# A few known statements for efficiency
if expr.is_Add: # We know that E is Linear
return Add(*[expectation(arg, evaluate=evaluate)
for arg in expr.args])
# Otherwise case is simple, pass work off to the ProbabilitySpace
result = pspace(expr).compute_expectation(expr, evaluate=evaluate, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit(**kwargs)
else:
return result
def probability(condition, given_condition=None, numsamples=None,
evaluate=True, **kwargs):
"""
Probability that a condition is true, optionally given a second condition
Parameters
==========
condition : Combination of Relationals containing RandomSymbols
The condition of which you want to compute the probability
given_condition : Combination of Relationals containing RandomSymbols
A conditional expression. P(X > 1, X > 0) is expectation of X > 1
given X > 0
numsamples : int
Enables sampling and approximates the probability with this many samples
evaluate : Bool (defaults to True)
In case of continuous systems return unevaluated integral
Examples
========
>>> from sympy.stats import P, Die
>>> from sympy import Eq
>>> X, Y = Die('X', 6), Die('Y', 6)
>>> P(X > 3)
1/2
>>> P(Eq(X, 5), X > 2) # Probability that X == 5 given that X > 2
1/4
>>> P(X > Y)
5/12
"""
condition = sympify(condition)
given_condition = sympify(given_condition)
if given_condition is not None and \
not isinstance(given_condition, (Relational, Boolean)):
raise ValueError("%s is not a relational or combination of relationals"
% (given_condition))
if given_condition == False:
return S.Zero
if not isinstance(condition, (Relational, Boolean)):
raise ValueError("%s is not a relational or combination of relationals"
% (condition))
if condition is S.true:
return S.One
if condition is S.false:
return S.Zero
if numsamples:
return sampling_P(condition, given_condition, numsamples=numsamples,
**kwargs)
if given_condition is not None: # If there is a condition
# Recompute on new conditional expr
return probability(given(condition, given_condition, **kwargs), **kwargs)
# Otherwise pass work off to the ProbabilitySpace
result = pspace(condition).probability(condition, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit()
else:
return result
class Density(Basic):
expr = property(lambda self: self.args[0])
@property
def condition(self):
if len(self.args) > 1:
return self.args[1]
else:
return None
def doit(self, evaluate=True, **kwargs):
from sympy.stats.joint_rv import JointPSpace
expr, condition = self.expr, self.condition
if condition is not None:
# Recompute on new conditional expr
expr = given(expr, condition, **kwargs)
if isinstance(expr, RandomSymbol) and \
isinstance(expr.pspace, JointPSpace):
return expr.pspace.distribution
if not random_symbols(expr):
return Lambda(x, DiracDelta(x - expr))
if (isinstance(expr, RandomSymbol) and
hasattr(expr.pspace, 'distribution') and
isinstance(pspace(expr), (SinglePSpace))):
return expr.pspace.distribution
result = pspace(expr).compute_density(expr, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit()
else:
return result
def density(expr, condition=None, evaluate=True, numsamples=None, **kwargs):
"""
Probability density of a random expression, optionally given a second
condition.
This density will take on different forms for different types of
probability spaces. Discrete variables produce Dicts. Continuous
variables produce Lambdas.
Parameters
==========
expr : Expr containing RandomSymbols
The expression of which you want to compute the density value
condition : Relational containing RandomSymbols
A conditional expression. density(X > 1, X > 0) is density of X > 1
given X > 0
numsamples : int
Enables sampling and approximates the density with this many samples
Examples
========
>>> from sympy.stats import density, Die, Normal
>>> from sympy import Symbol
>>> x = Symbol('x')
>>> D = Die('D', 6)
>>> X = Normal(x, 0, 1)
>>> density(D).dict
{1: 1/6, 2: 1/6, 3: 1/6, 4: 1/6, 5: 1/6, 6: 1/6}
>>> density(2*D).dict
{2: 1/6, 4: 1/6, 6: 1/6, 8: 1/6, 10: 1/6, 12: 1/6}
>>> density(X)(x)
sqrt(2)*exp(-x**2/2)/(2*sqrt(pi))
"""
if numsamples:
return sampling_density(expr, condition, numsamples=numsamples,
**kwargs)
return Density(expr, condition).doit(evaluate=evaluate, **kwargs)
def cdf(expr, condition=None, evaluate=True, **kwargs):
"""
Cumulative Distribution Function of a random expression.
optionally given a second condition
This density will take on different forms for different types of
probability spaces.
Discrete variables produce Dicts.
Continuous variables produce Lambdas.
Examples
========
>>> from sympy.stats import density, Die, Normal, cdf
>>> D = Die('D', 6)
>>> X = Normal('X', 0, 1)
>>> density(D).dict
{1: 1/6, 2: 1/6, 3: 1/6, 4: 1/6, 5: 1/6, 6: 1/6}
>>> cdf(D)
{1: 1/6, 2: 1/3, 3: 1/2, 4: 2/3, 5: 5/6, 6: 1}
>>> cdf(3*D, D > 2)
{9: 1/4, 12: 1/2, 15: 3/4, 18: 1}
>>> cdf(X)
Lambda(_z, erf(sqrt(2)*_z/2)/2 + 1/2)
"""
if condition is not None: # If there is a condition
# Recompute on new conditional expr
return cdf(given(expr, condition, **kwargs), **kwargs)
# Otherwise pass work off to the ProbabilitySpace
result = pspace(expr).compute_cdf(expr, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit()
else:
return result
def characteristic_function(expr, condition=None, evaluate=True, **kwargs):
"""
Characteristic function of a random expression, optionally given a second condition
Returns a Lambda
Examples
========
>>> from sympy.stats import Normal, DiscreteUniform, Poisson, characteristic_function
>>> X = Normal('X', 0, 1)
>>> characteristic_function(X)
Lambda(_t, exp(-_t**2/2))
>>> Y = DiscreteUniform('Y', [1, 2, 7])
>>> characteristic_function(Y)
Lambda(_t, exp(7*_t*I)/3 + exp(2*_t*I)/3 + exp(_t*I)/3)
>>> Z = Poisson('Z', 2)
>>> characteristic_function(Z)
Lambda(_t, exp(2*exp(_t*I) - 2))
"""
if condition is not None:
return characteristic_function(given(expr, condition, **kwargs), **kwargs)
result = pspace(expr).compute_characteristic_function(expr, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit()
else:
return result
def moment_generating_function(expr, condition=None, evaluate=True, **kwargs):
if condition is not None:
return moment_generating_function(given(expr, condition, **kwargs), **kwargs)
result = pspace(expr).compute_moment_generating_function(expr, **kwargs)
if evaluate and hasattr(result, 'doit'):
return result.doit()
else:
return result
def where(condition, given_condition=None, **kwargs):
"""
Returns the domain where a condition is True.
Examples
========
>>> from sympy.stats import where, Die, Normal
>>> from sympy import symbols, And
>>> D1, D2 = Die('a', 6), Die('b', 6)
>>> a, b = D1.symbol, D2.symbol
>>> X = Normal('x', 0, 1)
>>> where(X**2<1)
Domain: (-1 < x) & (x < 1)
>>> where(X**2<1).set
Interval.open(-1, 1)
>>> where(And(D1<=D2 , D2<3))
Domain: (Eq(a, 1) & Eq(b, 1)) | (Eq(a, 1) & Eq(b, 2)) | (Eq(a, 2) & Eq(b, 2))
"""
if given_condition is not None: # If there is a condition
# Recompute on new conditional expr
return where(given(condition, given_condition, **kwargs), **kwargs)
# Otherwise pass work off to the ProbabilitySpace
return pspace(condition).where(condition, **kwargs)
def sample(expr, condition=None, **kwargs):
"""
A realization of the random expression
Examples
========
>>> from sympy.stats import Die, sample
>>> X, Y, Z = Die('X', 6), Die('Y', 6), Die('Z', 6)
>>> die_roll = sample(X + Y + Z) # A random realization of three dice
"""
return next(sample_iter(expr, condition, numsamples=1))
def sample_iter(expr, condition=None, numsamples=S.Infinity, **kwargs):
"""
Returns an iterator of realizations from the expression given a condition
expr: Random expression to be realized
condition: A conditional expression (optional)
numsamples: Length of the iterator (defaults to infinity)
Examples
========
>>> from sympy.stats import Normal, sample_iter
>>> X = Normal('X', 0, 1)
>>> expr = X*X + 3
>>> iterator = sample_iter(expr, numsamples=3)
>>> list(iterator) # doctest: +SKIP
[12, 4, 7]
See Also
========
Sample
sampling_P
sampling_E
sample_iter_lambdify
sample_iter_subs
"""
# lambdify is much faster but not as robust
try:
return sample_iter_lambdify(expr, condition, numsamples, **kwargs)
# use subs when lambdify fails
except TypeError:
return sample_iter_subs(expr, condition, numsamples, **kwargs)
def sample_iter_lambdify(expr, condition=None, numsamples=S.Infinity, **kwargs):
"""
See sample_iter
Uses lambdify for computation. This is fast but does not always work.
"""
if condition:
ps = pspace(Tuple(expr, condition))
else:
ps = pspace(expr)
rvs = list(ps.values)
fn = lambdify(rvs, expr, **kwargs)
if condition:
given_fn = lambdify(rvs, condition, **kwargs)
# Check that lambdify can handle the expression
# Some operations like Sum can prove difficult
try:
d = ps.sample() # a dictionary that maps RVs to values
args = [d[rv] for rv in rvs]
fn(*args)
if condition:
given_fn(*args)
except Exception:
raise TypeError("Expr/condition too complex for lambdify")
def return_generator():
count = 0
while count < numsamples:
d = ps.sample() # a dictionary that maps RVs to values
args = [d[rv] for rv in rvs]
if condition: # Check that these values satisfy the condition
gd = given_fn(*args)
if gd != True and gd != False:
raise ValueError(
"Conditions must not contain free symbols")
if not gd: # If the values don't satisfy then try again
continue
yield fn(*args)
count += 1
return return_generator()
def sample_iter_subs(expr, condition=None, numsamples=S.Infinity, **kwargs):
"""
See sample_iter
Uses subs for computation. This is slow but almost always works.
"""
if condition is not None:
ps = pspace(Tuple(expr, condition))
else:
ps = pspace(expr)
count = 0
while count < numsamples:
d = ps.sample() # a dictionary that maps RVs to values
if condition is not None: # Check that these values satisfy the condition
gd = condition.xreplace(d)
if gd != True and gd != False:
raise ValueError("Conditions must not contain free symbols")
if not gd: # If the values don't satisfy then try again
continue
yield expr.xreplace(d)
count += 1
def sampling_P(condition, given_condition=None, numsamples=1,
evalf=True, **kwargs):
"""
Sampling version of P
See Also
========
P
sampling_E
sampling_density
"""
count_true = 0
count_false = 0
samples = sample_iter(condition, given_condition,
numsamples=numsamples, **kwargs)
for x in samples:
if x != True and x != False:
raise ValueError("Conditions must not contain free symbols")
if x:
count_true += 1
else:
count_false += 1
result = S(count_true) / numsamples
if evalf:
return result.evalf()
else:
return result
def sampling_E(expr, given_condition=None, numsamples=1,
evalf=True, **kwargs):
"""
Sampling version of E
See Also
========
P
sampling_P
sampling_density
"""
samples = sample_iter(expr, given_condition,
numsamples=numsamples, **kwargs)
result = Add(*list(samples)) / numsamples
if evalf:
return result.evalf()
else:
return result
def sampling_density(expr, given_condition=None, numsamples=1, **kwargs):
"""
Sampling version of density
See Also
========
density
sampling_P
sampling_E
"""
results = {}
for result in sample_iter(expr, given_condition,
numsamples=numsamples, **kwargs):
results[result] = results.get(result, 0) + 1
return results
def dependent(a, b):
"""
Dependence of two random expressions
Two expressions are independent if knowledge of one does not change
computations on the other.
Examples
========
>>> from sympy.stats import Normal, dependent, given
>>> from sympy import Tuple, Eq
>>> X, Y = Normal('X', 0, 1), Normal('Y', 0, 1)
>>> dependent(X, Y)
False
>>> dependent(2*X + Y, -Y)
True
>>> X, Y = given(Tuple(X, Y), Eq(X + Y, 3))
>>> dependent(X, Y)
True
See Also
========
independent
"""
if pspace_independent(a, b):
return False
z = Symbol('z', real=True)
# Dependent if density is unchanged when one is given information about
# the other
return (density(a, Eq(b, z)) != density(a) or
density(b, Eq(a, z)) != density(b))
def independent(a, b):
"""
Independence of two random expressions
Two expressions are independent if knowledge of one does not change
computations on the other.
Examples
========
>>> from sympy.stats import Normal, independent, given
>>> from sympy import Tuple, Eq
>>> X, Y = Normal('X', 0, 1), Normal('Y', 0, 1)
>>> independent(X, Y)
True
>>> independent(2*X + Y, -Y)
False
>>> X, Y = given(Tuple(X, Y), Eq(X + Y, 3))
>>> independent(X, Y)
False
See Also
========
dependent
"""
return not dependent(a, b)
def pspace_independent(a, b):
"""
Tests for independence between a and b by checking if their PSpaces have
overlapping symbols. This is a sufficient but not necessary condition for
independence and is intended to be used internally.
Notes
=====
pspace_independent(a, b) implies independent(a, b)
independent(a, b) does not imply pspace_independent(a, b)
"""
a_symbols = set(pspace(b).symbols)
b_symbols = set(pspace(a).symbols)
if len(set(random_symbols(a)).intersection(random_symbols(b))) != 0:
return False
if len(a_symbols.intersection(b_symbols)) == 0:
return True
return None
def rv_subs(expr, symbols=None):
"""
Given a random expression replace all random variables with their symbols.
If symbols keyword is given restrict the swap to only the symbols listed.
"""
if symbols is None:
symbols = random_symbols(expr)
if not symbols:
return expr
swapdict = {rv: rv.symbol for rv in symbols}
return expr.xreplace(swapdict)
class NamedArgsMixin(object):
_argnames = ()
def __getattr__(self, attr):
try:
return self.args[self._argnames.index(attr)]
except ValueError:
raise AttributeError("'%s' object has no attribute '%s'" % (
type(self).__name__, attr))
def _value_check(condition, message):
"""
Check a condition on input value.
Raises ValueError with message if condition is not True
"""
if condition == False:
raise ValueError(message)
|
50f92ddd6d6b0a7991c25ac399bab455fe7cf4f13728c39a6f4895851a1d9b59
|
"""
Joint Random Variables Module
See Also
========
sympy.stats.rv
sympy.stats.frv
sympy.stats.crv
sympy.stats.drv
"""
from __future__ import print_function, division
# __all__ = ['marginal_distribution']
from sympy import (Basic, Lambda, sympify, Indexed, Symbol, ProductSet, S,
Dummy, Mul)
from sympy.concrete.summations import Sum, summation
from sympy.integrals.integrals import Integral, integrate
from sympy.stats.rv import (ProductPSpace, NamedArgsMixin,
ProductDomain, RandomSymbol, random_symbols, SingleDomain)
from sympy.stats.crv import (ContinuousDistribution,
SingleContinuousDistribution, SingleContinuousPSpace)
from sympy.stats.drv import (DiscreteDistribution,
SingleDiscreteDistribution, SingleDiscretePSpace)
from sympy.core.compatibility import string_types
from sympy.matrices import ImmutableMatrix
from sympy.core.containers import Tuple
from sympy.utilities.misc import filldedent
class JointPSpace(ProductPSpace):
"""
Represents a joint probability space. Represented using symbols for
each component and a distribution.
"""
def __new__(cls, sym, dist):
if isinstance(dist, SingleContinuousDistribution):
return SingleContinuousPSpace(sym, dist)
if isinstance(dist, SingleDiscreteDistribution):
return SingleDiscretePSpace(sym, dist)
if isinstance(sym, string_types):
sym = Symbol(sym)
if not isinstance(sym, Symbol):
raise TypeError("s should have been string or Symbol")
return Basic.__new__(cls, sym, dist)
@property
def set(self):
return self.domain.set
@property
def symbol(self):
return self.args[0]
@property
def distribution(self):
return self.args[1]
@property
def value(self):
return JointRandomSymbol(self.symbol, self)
@property
def component_count(self):
_set = self.distribution.set
return len(_set.args) if isinstance(_set, ProductSet) else 1
@property
def pdf(self):
sym = [Indexed(self.symbol, i) for i in range(self.component_count)]
return self.distribution(*sym)
@property
def domain(self):
rvs = random_symbols(self.distribution)
if len(rvs) == 0:
return SingleDomain(self.symbol, self.set)
return ProductDomain(*[rv.pspace.domain for rv in rvs])
def component_domain(self, index):
return self.set.args[index]
@property
def symbols(self):
return self.domain.symbols
def marginal_distribution(self, *indices):
count = self.component_count
orig = [Indexed(self.symbol, i) for i in range(count)]
all_syms = [Symbol(str(i)) for i in orig]
replace_dict = dict(zip(all_syms, orig))
sym = [Symbol(str(Indexed(self.symbol, i))) for i in indices]
limits = list([i,] for i in all_syms if i not in sym)
index = 0
for i in range(count):
if i not in indices:
limits[index].append(self.distribution.set.args[i])
limits[index] = tuple(limits[index])
index += 1
limits = tuple(limits)
if self.distribution.is_Continuous:
f = Lambda(sym, integrate(self.distribution(*all_syms), limits))
elif self.distribution.is_Discrete:
f = Lambda(sym, summation(self.distribution(all_syms), limits))
return f.xreplace(replace_dict)
def compute_expectation(self, expr, rvs=None, evaluate=False, **kwargs):
syms = tuple(self.value[i] for i in range(self.component_count))
rvs = rvs or syms
if not any([i in rvs for i in syms]):
return expr
expr = expr*self.pdf
for rv in rvs:
if isinstance(rv, Indexed):
expr = expr.xreplace({rv: Indexed(str(rv.base), rv.args[1])})
elif isinstance(rv, RandomSymbol):
expr = expr.xreplace({rv: rv.symbol})
if self.value in random_symbols(expr):
raise NotImplementedError(filldedent('''
Expectations of expression with unindexed joint random symbols
cannot be calculated yet.'''))
limits = tuple((Indexed(str(rv.base),rv.args[1]),
self.distribution.set.args[rv.args[1]]) for rv in syms)
return Integral(expr, *limits)
def where(self, condition):
raise NotImplementedError()
def compute_density(self, expr):
raise NotImplementedError()
def sample(self):
raise NotImplementedError()
def probability(self, condition):
raise NotImplementedError()
class JointDistribution(Basic, NamedArgsMixin):
"""
Represented by the random variables part of the joint distribution.
Contains methods for PDF, CDF, sampling, marginal densities, etc.
"""
_argnames = ('pdf', )
def __new__(cls, *args):
args = list(map(sympify, args))
for i in range(len(args)):
if isinstance(args[i], list):
args[i] = ImmutableMatrix(args[i])
return Basic.__new__(cls, *args)
@property
def domain(self):
return ProductDomain(self.symbols)
@property
def pdf(self, *args):
return self.density.args[1]
def cdf(self, other):
assert isinstance(other, dict)
rvs = other.keys()
_set = self.domain.set
expr = self.pdf(tuple(i.args[0] for i in self.symbols))
for i in range(len(other)):
if rvs[i].is_Continuous:
density = Integral(expr, (rvs[i], _set[i].inf,
other[rvs[i]]))
elif rvs[i].is_Discrete:
density = Sum(expr, (rvs[i], _set[i].inf,
other[rvs[i]]))
return density
def __call__(self, *args):
return self.pdf(*args)
class JointRandomSymbol(RandomSymbol):
"""
Representation of random symbols with joint probability distributions
to allow indexing."
"""
def __getitem__(self, key):
from sympy.stats.joint_rv import JointPSpace
if isinstance(self.pspace, JointPSpace):
if self.pspace.component_count <= key:
raise ValueError("Index keys for %s can only up to %s." %
(self.name, self.pspace.component_count - 1))
return Indexed(self, key)
class JointDistributionHandmade(JointDistribution, NamedArgsMixin):
_argnames = ('pdf',)
is_Continuous = True
@property
def set(self):
return self.args[1]
def marginal_distribution(rv, *indices):
"""
Marginal distribution function of a joint random variable.
Parameters
==========
rv: A random variable with a joint probability distribution.
indices: component indices or the indexed random symbol
for whom the joint distribution is to be calculated
Returns
=======
A Lambda expression n `sym`.
Examples
========
>>> from sympy.stats.crv_types import Normal
>>> from sympy.stats.joint_rv import marginal_distribution
>>> m = Normal('X', [1, 2], [[2, 1], [1, 2]])
>>> marginal_distribution(m, m[0])(1)
1/(2*sqrt(pi))
"""
indices = list(indices)
for i in range(len(indices)):
if isinstance(indices[i], Indexed):
indices[i] = indices[i].args[1]
prob_space = rv.pspace
if indices == ():
raise ValueError(
"At least one component for marginal density is needed.")
if hasattr(prob_space.distribution, 'marginal_distribution'):
return prob_space.distribution.marginal_distribution(indices, rv.symbol)
return prob_space.marginal_distribution(*indices)
class CompoundDistribution(Basic, NamedArgsMixin):
"""
Represents a compound probability distribution.
Constructed using a single probability distribution with a parameter
distributed according to some given distribution.
"""
def __new__(cls, dist):
if not isinstance(dist, (ContinuousDistribution, DiscreteDistribution)):
raise ValueError(filldedent('''CompoundDistribution can only be
initialized from ContinuousDistribution or DiscreteDistribution
'''))
_args = dist.args
if not any([isinstance(i, RandomSymbol) for i in _args]):
return dist
return Basic.__new__(cls, dist)
@property
def latent_distributions(self):
return random_symbols(self.args[0])
def pdf(self, *x):
dist = self.args[0]
z = Dummy('z')
if isinstance(dist, ContinuousDistribution):
rv = SingleContinuousPSpace(z, dist).value
elif isinstance(dist, DiscreteDistribution):
rv = SingleDiscretePSpace(z, dist).value
return MarginalDistribution(self, (rv,)).pdf(*x)
def set(self):
return self.args[0].set
def __call__(self, *args):
return self.pdf(*args)
class MarginalDistribution(Basic):
"""
Represents the marginal distribution of a joint probability space.
Initialised using a probability distribution and random variables(or
their indexed components) which should be a part of the resultant
distribution.
"""
def __new__(cls,dist, rvs):
if not all([isinstance(rv, (Indexed, RandomSymbol))] for rv in rvs):
raise ValueError(filldedent('''Marginal distribution can be
intitialised only in terms of random variables or indexed random
variables'''))
rvs = Tuple.fromiter(rv for rv in rvs)
if not isinstance(dist, JointDistribution) and len(random_symbols(dist)) == 0:
return dist
return Basic.__new__(cls, dist, rvs)
def check(self):
pass
@property
def set(self):
rvs = [i for i in random_symbols(self.args[1])]
marginalise_out = [i for i in random_symbols(self.args[1]) \
if i not in self.args[1]]
for i in rvs:
if i in marginalise_out:
rvs.remove(i)
return ProductSet((i.pspace.set for i in rvs))
@property
def symbols(self):
rvs = self.args[1]
return set([rv.pspace.symbol for rv in rvs])
def pdf(self, *x):
expr, rvs = self.args[0], self.args[1]
marginalise_out = [i for i in random_symbols(expr) if i not in self.args[1]]
syms = [i.pspace.symbol for i in self.args[1]]
for i in expr.atoms(Indexed):
if isinstance(i, Indexed) and isinstance(i.base, RandomSymbol)\
and i not in rvs:
marginalise_out.append(i)
if isinstance(expr, CompoundDistribution):
syms = Dummy('x', real=True)
expr = expr.args[0].pdf(syms)
elif isinstance(expr, JointDistribution):
count = len(expr.domain.args)
x = Dummy('x', real=True, finite=True)
syms = [Indexed(x, i) for i in count]
expr = expression.pdf(syms)
return Lambda(syms, self.compute_pdf(expr, marginalise_out))(*x)
def compute_pdf(self, expr, rvs):
for rv in rvs:
lpdf = 1
if isinstance(rv, RandomSymbol):
lpdf = rv.pspace.pdf
expr = self.marginalise_out(expr*lpdf, rv)
return expr
def marginalise_out(self, expr, rv):
from sympy.concrete.summations import Sum
if isinstance(rv, RandomSymbol):
dom = rv.pspace.set
elif isinstance(rv, Indexed):
dom = rv.base.component_domain(
rv.pspace.component_domain(rv.args[1]))
expr = expr.xreplace({rv: rv.pspace.symbol})
if rv.pspace.is_Continuous:
#TODO: Modify to support integration
#for all kinds of sets.
expr = Integral(expr, (rv.pspace.symbol, dom))
elif rv.pspace.is_Discrete:
#incorporate this into `Sum`/`summation`
if dom in (S.Integers, S.Naturals, S.Naturals0):
dom = (dom.inf, dom.sup)
expr = Sum(expr, (rv.pspace.symbol, dom))
return expr
def __call__(self, *args):
return self.pdf(*args)
|
eb6de4e3ca49a58b5a75eb46a5f53bab2ab02ab81c7455a5b9957f2094b9e0bd
|
import itertools
from sympy.core.sympify import _sympify
from sympy.core.compatibility import default_sort_key
from sympy import Expr, Add, Mul, S, Integral, Eq, Sum, Symbol, Dummy, Basic
from sympy.core.evaluate import global_evaluate
from sympy.stats import variance, covariance
from sympy.stats.rv import RandomSymbol, probability, expectation
__all__ = ['Probability', 'Expectation', 'Variance', 'Covariance']
class Probability(Expr):
"""
Symbolic expression for the probability.
Examples
========
>>> from sympy.stats import Probability, Normal
>>> from sympy import Integral
>>> X = Normal("X", 0, 1)
>>> prob = Probability(X > 1)
>>> prob
Probability(X > 1)
Integral representation:
>>> prob.rewrite(Integral)
Integral(sqrt(2)*exp(-_z**2/2)/(2*sqrt(pi)), (_z, 1, oo))
Evaluation of the integral:
>>> prob.evaluate_integral()
sqrt(2)*(-sqrt(2)*sqrt(pi)*erf(sqrt(2)/2) + sqrt(2)*sqrt(pi))/(4*sqrt(pi))
"""
def __new__(cls, prob, condition=None, **kwargs):
prob = _sympify(prob)
if condition is None:
obj = Expr.__new__(cls, prob)
else:
condition = _sympify(condition)
obj = Expr.__new__(cls, prob, condition)
obj._condition = condition
return obj
def _eval_rewrite_as_Integral(self, arg, condition=None, **kwargs):
return probability(arg, condition, evaluate=False)
def _eval_rewrite_as_Sum(self, arg, condition=None, **kwargs):
return probability(arg, condition, evaluate=False)
def evaluate_integral(self):
return self.rewrite(Integral).doit()
class Expectation(Expr):
"""
Symbolic expression for the expectation.
Examples
========
>>> from sympy.stats import Expectation, Normal, Probability
>>> from sympy import symbols, Integral
>>> mu = symbols("mu")
>>> sigma = symbols("sigma", positive=True)
>>> X = Normal("X", mu, sigma)
>>> Expectation(X)
Expectation(X)
>>> Expectation(X).evaluate_integral().simplify()
mu
To get the integral expression of the expectation:
>>> Expectation(X).rewrite(Integral)
Integral(sqrt(2)*X*exp(-(X - mu)**2/(2*sigma**2))/(2*sqrt(pi)*sigma), (X, -oo, oo))
The same integral expression, in more abstract terms:
>>> Expectation(X).rewrite(Probability)
Integral(x*Probability(Eq(X, x)), (x, -oo, oo))
This class is aware of some properties of the expectation:
>>> from sympy.abc import a
>>> Expectation(a*X)
Expectation(a*X)
>>> Y = Normal("Y", 0, 1)
>>> Expectation(X + Y)
Expectation(X + Y)
To expand the ``Expectation`` into its expression, use ``doit()``:
>>> Expectation(X + Y).doit()
Expectation(X) + Expectation(Y)
>>> Expectation(a*X + Y).doit()
a*Expectation(X) + Expectation(Y)
>>> Expectation(a*X + Y)
Expectation(a*X + Y)
"""
def __new__(cls, expr, condition=None, **kwargs):
expr = _sympify(expr)
if condition is None:
if not expr.has(RandomSymbol):
return expr
obj = Expr.__new__(cls, expr)
else:
condition = _sympify(condition)
obj = Expr.__new__(cls, expr, condition)
obj._condition = condition
return obj
def doit(self, **hints):
expr = self.args[0]
condition = self._condition
if not expr.has(RandomSymbol):
return expr
if isinstance(expr, Add):
return Add(*[Expectation(a, condition=condition).doit() for a in expr.args])
elif isinstance(expr, Mul):
rv = []
nonrv = []
for a in expr.args:
if isinstance(a, RandomSymbol) or a.has(RandomSymbol):
rv.append(a)
else:
nonrv.append(a)
return Mul(*nonrv)*Expectation(Mul(*rv), condition=condition)
return self
def _eval_rewrite_as_Probability(self, arg, condition=None, **kwargs):
rvs = arg.atoms(RandomSymbol)
if len(rvs) > 1:
raise NotImplementedError()
if len(rvs) == 0:
return arg
rv = rvs.pop()
if rv.pspace is None:
raise ValueError("Probability space not known")
symbol = rv.symbol
if symbol.name[0].isupper():
symbol = Symbol(symbol.name.lower())
else :
symbol = Symbol(symbol.name + "_1")
if rv.pspace.is_Continuous:
return Integral(arg.replace(rv, symbol)*Probability(Eq(rv, symbol), condition), (symbol, rv.pspace.domain.set.inf, rv.pspace.domain.set.sup))
else:
if rv.pspace.is_Finite:
raise NotImplementedError
else:
return Sum(arg.replace(rv, symbol)*Probability(Eq(rv, symbol), condition), (symbol, rv.pspace.domain.set.inf, rv.pspace.set.sup))
def _eval_rewrite_as_Integral(self, arg, condition=None, **kwargs):
return expectation(arg, condition=condition, evaluate=False)
def _eval_rewrite_as_Sum(self, arg, condition=None, **kwargs):
return self.rewrite(Integral)
def evaluate_integral(self):
return self.rewrite(Integral).doit()
class Variance(Expr):
"""
Symbolic expression for the variance.
Examples
========
>>> from sympy import symbols, Integral
>>> from sympy.stats import Normal, Expectation, Variance, Probability
>>> mu = symbols("mu", positive=True)
>>> sigma = symbols("sigma", positive=True)
>>> X = Normal("X", mu, sigma)
>>> Variance(X)
Variance(X)
>>> Variance(X).evaluate_integral()
sigma**2
Integral representation of the underlying calculations:
>>> Variance(X).rewrite(Integral)
Integral(sqrt(2)*(X - Integral(sqrt(2)*X*exp(-(X - mu)**2/(2*sigma**2))/(2*sqrt(pi)*sigma), (X, -oo, oo)))**2*exp(-(X - mu)**2/(2*sigma**2))/(2*sqrt(pi)*sigma), (X, -oo, oo))
Integral representation, without expanding the PDF:
>>> Variance(X).rewrite(Probability)
-Integral(x*Probability(Eq(X, x)), (x, -oo, oo))**2 + Integral(x**2*Probability(Eq(X, x)), (x, -oo, oo))
Rewrite the variance in terms of the expectation
>>> Variance(X).rewrite(Expectation)
-Expectation(X)**2 + Expectation(X**2)
Some transformations based on the properties of the variance may happen:
>>> from sympy.abc import a
>>> Y = Normal("Y", 0, 1)
>>> Variance(a*X)
Variance(a*X)
To expand the variance in its expression, use ``doit()``:
>>> Variance(a*X).doit()
a**2*Variance(X)
>>> Variance(X + Y)
Variance(X + Y)
>>> Variance(X + Y).doit()
2*Covariance(X, Y) + Variance(X) + Variance(Y)
"""
def __new__(cls, arg, condition=None, **kwargs):
arg = _sympify(arg)
if condition is None:
obj = Expr.__new__(cls, arg)
else:
condition = _sympify(condition)
obj = Expr.__new__(cls, arg, condition)
obj._condition = condition
return obj
def doit(self, **hints):
arg = self.args[0]
condition = self._condition
if not arg.has(RandomSymbol):
return S.Zero
if isinstance(arg, RandomSymbol):
return self
elif isinstance(arg, Add):
rv = []
for a in arg.args:
if a.has(RandomSymbol):
rv.append(a)
variances = Add(*map(lambda xv: Variance(xv, condition).doit(), rv))
map_to_covar = lambda x: 2*Covariance(*x, condition=condition).doit()
covariances = Add(*map(map_to_covar, itertools.combinations(rv, 2)))
return variances + covariances
elif isinstance(arg, Mul):
nonrv = []
rv = []
for a in arg.args:
if a.has(RandomSymbol):
rv.append(a)
else:
nonrv.append(a**2)
if len(rv) == 0:
return S.Zero
return Mul(*nonrv)*Variance(Mul(*rv), condition)
# this expression contains a RandomSymbol somehow:
return self
def _eval_rewrite_as_Expectation(self, arg, condition=None, **kwargs):
e1 = Expectation(arg**2, condition)
e2 = Expectation(arg, condition)**2
return e1 - e2
def _eval_rewrite_as_Probability(self, arg, condition=None, **kwargs):
return self.rewrite(Expectation).rewrite(Probability)
def _eval_rewrite_as_Integral(self, arg, condition=None, **kwargs):
return variance(self.args[0], self._condition, evaluate=False)
def _eval_rewrite_as_Sum(self, arg, condition=None, **kwargs):
return self.rewrite(Integral)
def evaluate_integral(self):
return self.rewrite(Integral).doit()
class Covariance(Expr):
"""
Symbolic expression for the covariance.
Examples
========
>>> from sympy.stats import Covariance
>>> from sympy.stats import Normal
>>> X = Normal("X", 3, 2)
>>> Y = Normal("Y", 0, 1)
>>> Z = Normal("Z", 0, 1)
>>> W = Normal("W", 0, 1)
>>> cexpr = Covariance(X, Y)
>>> cexpr
Covariance(X, Y)
Evaluate the covariance, `X` and `Y` are independent,
therefore zero is the result:
>>> cexpr.evaluate_integral()
0
Rewrite the covariance expression in terms of expectations:
>>> from sympy.stats import Expectation
>>> cexpr.rewrite(Expectation)
Expectation(X*Y) - Expectation(X)*Expectation(Y)
In order to expand the argument, use ``doit()``:
>>> from sympy.abc import a, b, c, d
>>> Covariance(a*X + b*Y, c*Z + d*W)
Covariance(a*X + b*Y, c*Z + d*W)
>>> Covariance(a*X + b*Y, c*Z + d*W).doit()
a*c*Covariance(X, Z) + a*d*Covariance(W, X) + b*c*Covariance(Y, Z) + b*d*Covariance(W, Y)
This class is aware of some properties of the covariance:
>>> Covariance(X, X).doit()
Variance(X)
>>> Covariance(a*X, b*Y).doit()
a*b*Covariance(X, Y)
"""
def __new__(cls, arg1, arg2, condition=None, **kwargs):
arg1 = _sympify(arg1)
arg2 = _sympify(arg2)
if kwargs.pop('evaluate', global_evaluate[0]):
arg1, arg2 = sorted([arg1, arg2], key=default_sort_key)
if condition is None:
obj = Expr.__new__(cls, arg1, arg2)
else:
condition = _sympify(condition)
obj = Expr.__new__(cls, arg1, arg2, condition)
obj._condition = condition
return obj
def doit(self, **hints):
arg1 = self.args[0]
arg2 = self.args[1]
condition = self._condition
if arg1 == arg2:
return Variance(arg1, condition).doit()
if not arg1.has(RandomSymbol):
return S.Zero
if not arg2.has(RandomSymbol):
return S.Zero
arg1, arg2 = sorted([arg1, arg2], key=default_sort_key)
if isinstance(arg1, RandomSymbol) and isinstance(arg2, RandomSymbol):
return Covariance(arg1, arg2, condition)
coeff_rv_list1 = self._expand_single_argument(arg1.expand())
coeff_rv_list2 = self._expand_single_argument(arg2.expand())
addends = [a*b*Covariance(*sorted([r1, r2], key=default_sort_key), condition=condition)
for (a, r1) in coeff_rv_list1 for (b, r2) in coeff_rv_list2]
return Add(*addends)
@classmethod
def _expand_single_argument(cls, expr):
# return (coefficient, random_symbol) pairs:
if isinstance(expr, RandomSymbol):
return [(S.One, expr)]
elif isinstance(expr, Add):
outval = []
for a in expr.args:
if isinstance(a, Mul):
outval.append(cls._get_mul_nonrv_rv_tuple(a))
elif isinstance(a, RandomSymbol):
outval.append((S.One, a))
return outval
elif isinstance(expr, Mul):
return [cls._get_mul_nonrv_rv_tuple(expr)]
elif expr.has(RandomSymbol):
return [(S.One, expr)]
@classmethod
def _get_mul_nonrv_rv_tuple(cls, m):
rv = []
nonrv = []
for a in m.args:
if a.has(RandomSymbol):
rv.append(a)
else:
nonrv.append(a)
return (Mul(*nonrv), Mul(*rv))
def _eval_rewrite_as_Expectation(self, arg1, arg2, condition=None, **kwargs):
e1 = Expectation(arg1*arg2, condition)
e2 = Expectation(arg1, condition)*Expectation(arg2, condition)
return e1 - e2
def _eval_rewrite_as_Probability(self, arg1, arg2, condition=None, **kwargs):
return self.rewrite(Expectation).rewrite(Probability)
def _eval_rewrite_as_Integral(self, arg1, arg2, condition=None, **kwargs):
return covariance(self.args[0], self.args[1], self._condition, evaluate=False)
def _eval_rewrite_as_Sum(self, arg1, arg2, condition=None, **kwargs):
return self.rewrite(Integral)
def evaluate_integral(self):
return self.rewrite(Integral).doit()
|
eb03226bb5eebcbd820338cd8e10e4a406fd1ea642f3a390b8277f9bb24e06de
|
"""
Integer factorization
"""
from __future__ import print_function, division
import random
import math
from .primetest import isprime
from .generate import sieve, primerange, nextprime
from sympy.core import sympify
from sympy.core.evalf import bitcount
from sympy.core.logic import fuzzy_and
from sympy.core.numbers import igcd, ilcm, Rational
from sympy.core.power import integer_nthroot, Pow
from sympy.core.mul import Mul
from sympy.core.compatibility import as_int, SYMPY_INTS, range
from sympy.core.singleton import S
from sympy.core.function import Function
from sympy.core.expr import Expr
small_trailing = [i and max(int(not i % 2**j) and j for j in range(1, 8))
for i in range(256)]
def smoothness(n):
"""
Return the B-smooth and B-power smooth values of n.
The smoothness of n is the largest prime factor of n; the power-
smoothness is the largest divisor raised to its multiplicity.
>>> from sympy.ntheory.factor_ import smoothness
>>> smoothness(2**7*3**2)
(3, 128)
>>> smoothness(2**4*13)
(13, 16)
>>> smoothness(2)
(2, 2)
See Also
========
factorint, smoothness_p
"""
if n == 1:
return (1, 1) # not prime, but otherwise this causes headaches
facs = factorint(n)
return max(facs), max(m**facs[m] for m in facs)
def smoothness_p(n, m=-1, power=0, visual=None):
"""
Return a list of [m, (p, (M, sm(p + m), psm(p + m)))...]
where:
1. p**M is the base-p divisor of n
2. sm(p + m) is the smoothness of p + m (m = -1 by default)
3. psm(p + m) is the power smoothness of p + m
The list is sorted according to smoothness (default) or by power smoothness
if power=1.
The smoothness of the numbers to the left (m = -1) or right (m = 1) of a
factor govern the results that are obtained from the p +/- 1 type factoring
methods.
>>> from sympy.ntheory.factor_ import smoothness_p, factorint
>>> smoothness_p(10431, m=1)
(1, [(3, (2, 2, 4)), (19, (1, 5, 5)), (61, (1, 31, 31))])
>>> smoothness_p(10431)
(-1, [(3, (2, 2, 2)), (19, (1, 3, 9)), (61, (1, 5, 5))])
>>> smoothness_p(10431, power=1)
(-1, [(3, (2, 2, 2)), (61, (1, 5, 5)), (19, (1, 3, 9))])
If visual=True then an annotated string will be returned:
>>> print(smoothness_p(21477639576571, visual=1))
p**i=4410317**1 has p-1 B=1787, B-pow=1787
p**i=4869863**1 has p-1 B=2434931, B-pow=2434931
This string can also be generated directly from a factorization dictionary
and vice versa:
>>> factorint(17*9)
{3: 2, 17: 1}
>>> smoothness_p(_)
'p**i=3**2 has p-1 B=2, B-pow=2\\np**i=17**1 has p-1 B=2, B-pow=16'
>>> smoothness_p(_)
{3: 2, 17: 1}
The table of the output logic is:
====== ====== ======= =======
| Visual
------ ----------------------
Input True False other
====== ====== ======= =======
dict str tuple str
str str tuple dict
tuple str tuple str
n str tuple tuple
mul str tuple tuple
====== ====== ======= =======
See Also
========
factorint, smoothness
"""
from sympy.utilities import flatten
# visual must be True, False or other (stored as None)
if visual in (1, 0):
visual = bool(visual)
elif visual not in (True, False):
visual = None
if type(n) is str:
if visual:
return n
d = {}
for li in n.splitlines():
k, v = [int(i) for i in
li.split('has')[0].split('=')[1].split('**')]
d[k] = v
if visual is not True and visual is not False:
return d
return smoothness_p(d, visual=False)
elif type(n) is not tuple:
facs = factorint(n, visual=False)
if power:
k = -1
else:
k = 1
if type(n) is not tuple:
rv = (m, sorted([(f,
tuple([M] + list(smoothness(f + m))))
for f, M in [i for i in facs.items()]],
key=lambda x: (x[1][k], x[0])))
else:
rv = n
if visual is False or (visual is not True) and (type(n) in [int, Mul]):
return rv
lines = []
for dat in rv[1]:
dat = flatten(dat)
dat.insert(2, m)
lines.append('p**i=%i**%i has p%+i B=%i, B-pow=%i' % tuple(dat))
return '\n'.join(lines)
def trailing(n):
"""Count the number of trailing zero digits in the binary
representation of n, i.e. determine the largest power of 2
that divides n.
Examples
========
>>> from sympy import trailing
>>> trailing(128)
7
>>> trailing(63)
0
"""
n = abs(int(n))
if not n:
return 0
low_byte = n & 0xff
if low_byte:
return small_trailing[low_byte]
# 2**m is quick for z up through 2**30
z = bitcount(n) - 1
if isinstance(z, SYMPY_INTS):
if n == 1 << z:
return z
t = 0
p = 8
while not n & 1:
while not n & ((1 << p) - 1):
n >>= p
t += p
p *= 2
p //= 2
return t
def multiplicity(p, n):
"""
Find the greatest integer m such that p**m divides n.
Examples
========
>>> from sympy.ntheory import multiplicity
>>> from sympy.core.numbers import Rational as R
>>> [multiplicity(5, n) for n in [8, 5, 25, 125, 250]]
[0, 1, 2, 3, 3]
>>> multiplicity(3, R(1, 9))
-2
"""
try:
p, n = as_int(p), as_int(n)
except ValueError:
if all(isinstance(i, (SYMPY_INTS, Rational)) for i in (p, n)):
try:
p = Rational(p)
n = Rational(n)
if p.q == 1:
if n.p == 1:
return -multiplicity(p.p, n.q)
return multiplicity(p.p, n.p) - multiplicity(p.p, n.q)
elif p.p == 1:
return multiplicity(p.q, n.q)
else:
like = min(
multiplicity(p.p, n.p),
multiplicity(p.q, n.q))
cross = min(
multiplicity(p.q, n.p),
multiplicity(p.p, n.q))
return like - cross
except AttributeError:
pass
raise ValueError('expecting ints or fractions, got %s and %s' % (p, n))
if n == 0:
raise ValueError('no such integer exists: multiplicity of %s is not-defined' %(n))
if p == 2:
return trailing(n)
if p < 2:
raise ValueError('p must be an integer, 2 or larger, but got %s' % p)
if p == n:
return 1
m = 0
n, rem = divmod(n, p)
while not rem:
m += 1
if m > 5:
# The multiplicity could be very large. Better
# to increment in powers of two
e = 2
while 1:
ppow = p**e
if ppow < n:
nnew, rem = divmod(n, ppow)
if not rem:
m += e
e *= 2
n = nnew
continue
return m + multiplicity(p, n)
n, rem = divmod(n, p)
return m
def perfect_power(n, candidates=None, big=True, factor=True):
"""
Return ``(b, e)`` such that ``n`` == ``b**e`` if ``n`` is a
perfect power; otherwise return ``False``.
By default, the base is recursively decomposed and the exponents
collected so the largest possible ``e`` is sought. If ``big=False``
then the smallest possible ``e`` (thus prime) will be chosen.
If ``candidates`` for exponents are given, they are assumed to be sorted
and the first one that is larger than the computed maximum will signal
failure for the routine.
If ``factor=True`` then simultaneous factorization of n is attempted
since finding a factor indicates the only possible root for n. This
is True by default since only a few small factors will be tested in
the course of searching for the perfect power.
Examples
========
>>> from sympy import perfect_power
>>> perfect_power(16)
(2, 4)
>>> perfect_power(16, big = False)
(4, 2)
"""
n = int(n)
if n < 3:
return False
logn = math.log(n, 2)
max_possible = int(logn) + 2 # only check values less than this
not_square = n % 10 in [2, 3, 7, 8] # squares cannot end in 2, 3, 7, 8
if not candidates:
candidates = primerange(2 + not_square, max_possible)
afactor = 2 + n % 2
for e in candidates:
if e < 3:
if e == 1 or e == 2 and not_square:
continue
if e > max_possible:
return False
# see if there is a factor present
if factor:
if n % afactor == 0:
# find what the potential power is
if afactor == 2:
e = trailing(n)
else:
e = multiplicity(afactor, n)
# if it's a trivial power we are done
if e == 1:
return False
# maybe the bth root of n is exact
r, exact = integer_nthroot(n, e)
if not exact:
# then remove this factor and check to see if
# any of e's factors are a common exponent; if
# not then it's not a perfect power
n //= afactor**e
m = perfect_power(n, candidates=primefactors(e), big=big)
if m is False:
return False
else:
r, m = m
# adjust the two exponents so the bases can
# be combined
g = igcd(m, e)
if g == 1:
return False
m //= g
e //= g
r, e = r**m*afactor**e, g
if not big:
e0 = primefactors(e)
if len(e0) > 1 or e0[0] != e:
e0 = e0[0]
r, e = r**(e//e0), e0
return r, e
else:
# get the next factor ready for the next pass through the loop
afactor = nextprime(afactor)
# Weed out downright impossible candidates
if logn/e < 40:
b = 2.0**(logn/e)
if abs(int(b + 0.5) - b) > 0.01:
continue
# now see if the plausible e makes a perfect power
r, exact = integer_nthroot(n, e)
if exact:
if big:
m = perfect_power(r, big=big, factor=factor)
if m is not False:
r, e = m[0], e*m[1]
return int(r), e
else:
return False
def pollard_rho(n, s=2, a=1, retries=5, seed=1234, max_steps=None, F=None):
r"""
Use Pollard's rho method to try to extract a nontrivial factor
of ``n``. The returned factor may be a composite number. If no
factor is found, ``None`` is returned.
The algorithm generates pseudo-random values of x with a generator
function, replacing x with F(x). If F is not supplied then the
function x**2 + ``a`` is used. The first value supplied to F(x) is ``s``.
Upon failure (if ``retries`` is > 0) a new ``a`` and ``s`` will be
supplied; the ``a`` will be ignored if F was supplied.
The sequence of numbers generated by such functions generally have a
a lead-up to some number and then loop around back to that number and
begin to repeat the sequence, e.g. 1, 2, 3, 4, 5, 3, 4, 5 -- this leader
and loop look a bit like the Greek letter rho, and thus the name, 'rho'.
For a given function, very different leader-loop values can be obtained
so it is a good idea to allow for retries:
>>> from sympy.ntheory.generate import cycle_length
>>> n = 16843009
>>> F = lambda x:(2048*pow(x, 2, n) + 32767) % n
>>> for s in range(5):
... print('loop length = %4i; leader length = %3i' % next(cycle_length(F, s)))
...
loop length = 2489; leader length = 42
loop length = 78; leader length = 120
loop length = 1482; leader length = 99
loop length = 1482; leader length = 285
loop length = 1482; leader length = 100
Here is an explicit example where there is a two element leadup to
a sequence of 3 numbers (11, 14, 4) that then repeat:
>>> x=2
>>> for i in range(9):
... x=(x**2+12)%17
... print(x)
...
16
13
11
14
4
11
14
4
11
>>> next(cycle_length(lambda x: (x**2+12)%17, 2))
(3, 2)
>>> list(cycle_length(lambda x: (x**2+12)%17, 2, values=True))
[16, 13, 11, 14, 4]
Instead of checking the differences of all generated values for a gcd
with n, only the kth and 2*kth numbers are checked, e.g. 1st and 2nd,
2nd and 4th, 3rd and 6th until it has been detected that the loop has been
traversed. Loops may be many thousands of steps long before rho finds a
factor or reports failure. If ``max_steps`` is specified, the iteration
is cancelled with a failure after the specified number of steps.
Examples
========
>>> from sympy import pollard_rho
>>> n=16843009
>>> F=lambda x:(2048*pow(x,2,n) + 32767) % n
>>> pollard_rho(n, F=F)
257
Use the default setting with a bad value of ``a`` and no retries:
>>> pollard_rho(n, a=n-2, retries=0)
If retries is > 0 then perhaps the problem will correct itself when
new values are generated for a:
>>> pollard_rho(n, a=n-2, retries=1)
257
References
==========
- Richard Crandall & Carl Pomerance (2005), "Prime Numbers:
A Computational Perspective", Springer, 2nd edition, 229-231
"""
n = int(n)
if n < 5:
raise ValueError('pollard_rho should receive n > 4')
prng = random.Random(seed + retries)
V = s
for i in range(retries + 1):
U = V
if not F:
F = lambda x: (pow(x, 2, n) + a) % n
j = 0
while 1:
if max_steps and (j > max_steps):
break
j += 1
U = F(U)
V = F(F(V)) # V is 2x further along than U
g = igcd(U - V, n)
if g == 1:
continue
if g == n:
break
return int(g)
V = prng.randint(0, n - 1)
a = prng.randint(1, n - 3) # for x**2 + a, a%n should not be 0 or -2
F = None
return None
def pollard_pm1(n, B=10, a=2, retries=0, seed=1234):
"""
Use Pollard's p-1 method to try to extract a nontrivial factor
of ``n``. Either a divisor (perhaps composite) or ``None`` is returned.
The value of ``a`` is the base that is used in the test gcd(a**M - 1, n).
The default is 2. If ``retries`` > 0 then if no factor is found after the
first attempt, a new ``a`` will be generated randomly (using the ``seed``)
and the process repeated.
Note: the value of M is lcm(1..B) = reduce(ilcm, range(2, B + 1)).
A search is made for factors next to even numbers having a power smoothness
less than ``B``. Choosing a larger B increases the likelihood of finding a
larger factor but takes longer. Whether a factor of n is found or not
depends on ``a`` and the power smoothness of the even number just less than
the factor p (hence the name p - 1).
Although some discussion of what constitutes a good ``a`` some
descriptions are hard to interpret. At the modular.math site referenced
below it is stated that if gcd(a**M - 1, n) = N then a**M % q**r is 1
for every prime power divisor of N. But consider the following:
>>> from sympy.ntheory.factor_ import smoothness_p, pollard_pm1
>>> n=257*1009
>>> smoothness_p(n)
(-1, [(257, (1, 2, 256)), (1009, (1, 7, 16))])
So we should (and can) find a root with B=16:
>>> pollard_pm1(n, B=16, a=3)
1009
If we attempt to increase B to 256 we find that it doesn't work:
>>> pollard_pm1(n, B=256)
>>>
But if the value of ``a`` is changed we find that only multiples of
257 work, e.g.:
>>> pollard_pm1(n, B=256, a=257)
1009
Checking different ``a`` values shows that all the ones that didn't
work had a gcd value not equal to ``n`` but equal to one of the
factors:
>>> from sympy.core.numbers import ilcm, igcd
>>> from sympy import factorint, Pow
>>> M = 1
>>> for i in range(2, 256):
... M = ilcm(M, i)
...
>>> set([igcd(pow(a, M, n) - 1, n) for a in range(2, 256) if
... igcd(pow(a, M, n) - 1, n) != n])
{1009}
But does aM % d for every divisor of n give 1?
>>> aM = pow(255, M, n)
>>> [(d, aM%Pow(*d.args)) for d in factorint(n, visual=True).args]
[(257**1, 1), (1009**1, 1)]
No, only one of them. So perhaps the principle is that a root will
be found for a given value of B provided that:
1) the power smoothness of the p - 1 value next to the root
does not exceed B
2) a**M % p != 1 for any of the divisors of n.
By trying more than one ``a`` it is possible that one of them
will yield a factor.
Examples
========
With the default smoothness bound, this number can't be cracked:
>>> from sympy.ntheory import pollard_pm1, primefactors
>>> pollard_pm1(21477639576571)
Increasing the smoothness bound helps:
>>> pollard_pm1(21477639576571, B=2000)
4410317
Looking at the smoothness of the factors of this number we find:
>>> from sympy.utilities import flatten
>>> from sympy.ntheory.factor_ import smoothness_p, factorint
>>> print(smoothness_p(21477639576571, visual=1))
p**i=4410317**1 has p-1 B=1787, B-pow=1787
p**i=4869863**1 has p-1 B=2434931, B-pow=2434931
The B and B-pow are the same for the p - 1 factorizations of the divisors
because those factorizations had a very large prime factor:
>>> factorint(4410317 - 1)
{2: 2, 617: 1, 1787: 1}
>>> factorint(4869863-1)
{2: 1, 2434931: 1}
Note that until B reaches the B-pow value of 1787, the number is not cracked;
>>> pollard_pm1(21477639576571, B=1786)
>>> pollard_pm1(21477639576571, B=1787)
4410317
The B value has to do with the factors of the number next to the divisor,
not the divisors themselves. A worst case scenario is that the number next
to the factor p has a large prime divisisor or is a perfect power. If these
conditions apply then the power-smoothness will be about p/2 or p. The more
realistic is that there will be a large prime factor next to p requiring
a B value on the order of p/2. Although primes may have been searched for
up to this level, the p/2 is a factor of p - 1, something that we don't
know. The modular.math reference below states that 15% of numbers in the
range of 10**15 to 15**15 + 10**4 are 10**6 power smooth so a B of 10**6
will fail 85% of the time in that range. From 10**8 to 10**8 + 10**3 the
percentages are nearly reversed...but in that range the simple trial
division is quite fast.
References
==========
- Richard Crandall & Carl Pomerance (2005), "Prime Numbers:
A Computational Perspective", Springer, 2nd edition, 236-238
- http://modular.math.washington.edu/edu/2007/spring/ent/ent-html/node81.html
- https://www.cs.toronto.edu/~yuvalf/Factorization.pdf
"""
n = int(n)
if n < 4 or B < 3:
raise ValueError('pollard_pm1 should receive n > 3 and B > 2')
prng = random.Random(seed + B)
# computing a**lcm(1,2,3,..B) % n for B > 2
# it looks weird, but it's right: primes run [2, B]
# and the answer's not right until the loop is done.
for i in range(retries + 1):
aM = a
for p in sieve.primerange(2, B + 1):
e = int(math.log(B, p))
aM = pow(aM, pow(p, e), n)
g = igcd(aM - 1, n)
if 1 < g < n:
return int(g)
# get a new a:
# since the exponent, lcm(1..B), is even, if we allow 'a' to be 'n-1'
# then (n - 1)**even % n will be 1 which will give a g of 0 and 1 will
# give a zero, too, so we set the range as [2, n-2]. Some references
# say 'a' should be coprime to n, but either will detect factors.
a = prng.randint(2, n - 2)
def _trial(factors, n, candidates, verbose=False):
"""
Helper function for integer factorization. Trial factors ``n`
against all integers given in the sequence ``candidates``
and updates the dict ``factors`` in-place. Returns the reduced
value of ``n`` and a flag indicating whether any factors were found.
"""
if verbose:
factors0 = list(factors.keys())
nfactors = len(factors)
for d in candidates:
if n % d == 0:
m = multiplicity(d, n)
n //= d**m
factors[d] = m
if verbose:
for k in sorted(set(factors).difference(set(factors0))):
print(factor_msg % (k, factors[k]))
return int(n), len(factors) != nfactors
def _check_termination(factors, n, limitp1, use_trial, use_rho, use_pm1,
verbose):
"""
Helper function for integer factorization. Checks if ``n``
is a prime or a perfect power, and in those cases updates
the factorization and raises ``StopIteration``.
"""
if verbose:
print('Check for termination')
# since we've already been factoring there is no need to do
# simultaneous factoring with the power check
p = perfect_power(n, factor=False)
if p is not False:
base, exp = p
if limitp1:
limit = limitp1 - 1
else:
limit = limitp1
facs = factorint(base, limit, use_trial, use_rho, use_pm1,
verbose=False)
for b, e in facs.items():
if verbose:
print(factor_msg % (b, e))
factors[b] = exp*e
raise StopIteration
if isprime(n):
factors[int(n)] = 1
raise StopIteration
if n == 1:
raise StopIteration
trial_int_msg = "Trial division with ints [%i ... %i] and fail_max=%i"
trial_msg = "Trial division with primes [%i ... %i]"
rho_msg = "Pollard's rho with retries %i, max_steps %i and seed %i"
pm1_msg = "Pollard's p-1 with smoothness bound %i and seed %i"
factor_msg = '\t%i ** %i'
fermat_msg = 'Close factors satisying Fermat condition found.'
complete_msg = 'Factorization is complete.'
def _factorint_small(factors, n, limit, fail_max):
"""
Return the value of n and either a 0 (indicating that factorization up
to the limit was complete) or else the next near-prime that would have
been tested.
Factoring stops if there are fail_max unsuccessful tests in a row.
If factors of n were found they will be in the factors dictionary as
{factor: multiplicity} and the returned value of n will have had those
factors removed. The factors dictionary is modified in-place.
"""
def done(n, d):
"""return n, d if the sqrt(n) wasn't reached yet, else
n, 0 indicating that factoring is done.
"""
if d*d <= n:
return n, d
return n, 0
d = 2
m = trailing(n)
if m:
factors[d] = m
n >>= m
d = 3
if limit < d:
if n > 1:
factors[n] = 1
return done(n, d)
# reduce
m = 0
while n % d == 0:
n //= d
m += 1
if m == 20:
mm = multiplicity(d, n)
m += mm
n //= d**mm
break
if m:
factors[d] = m
# when d*d exceeds maxx or n we are done; if limit**2 is greater
# than n then maxx is set to zero so the value of n will flag the finish
if limit*limit > n:
maxx = 0
else:
maxx = limit*limit
dd = maxx or n
d = 5
fails = 0
while fails < fail_max:
if d*d > dd:
break
# d = 6*i - 1
# reduce
m = 0
while n % d == 0:
n //= d
m += 1
if m == 20:
mm = multiplicity(d, n)
m += mm
n //= d**mm
break
if m:
factors[d] = m
dd = maxx or n
fails = 0
else:
fails += 1
d += 2
if d*d > dd:
break
# d = 6*i - 1
# reduce
m = 0
while n % d == 0:
n //= d
m += 1
if m == 20:
mm = multiplicity(d, n)
m += mm
n //= d**mm
break
if m:
factors[d] = m
dd = maxx or n
fails = 0
else:
fails += 1
# d = 6*(i + 1) - 1
d += 4
return done(n, d)
def factorint(n, limit=None, use_trial=True, use_rho=True, use_pm1=True,
verbose=False, visual=None, multiple=False):
r"""
Given a positive integer ``n``, ``factorint(n)`` returns a dict containing
the prime factors of ``n`` as keys and their respective multiplicities
as values. For example:
>>> from sympy.ntheory import factorint
>>> factorint(2000) # 2000 = (2**4) * (5**3)
{2: 4, 5: 3}
>>> factorint(65537) # This number is prime
{65537: 1}
For input less than 2, factorint behaves as follows:
- ``factorint(1)`` returns the empty factorization, ``{}``
- ``factorint(0)`` returns ``{0:1}``
- ``factorint(-n)`` adds ``-1:1`` to the factors and then factors ``n``
Partial Factorization:
If ``limit`` (> 3) is specified, the search is stopped after performing
trial division up to (and including) the limit (or taking a
corresponding number of rho/p-1 steps). This is useful if one has
a large number and only is interested in finding small factors (if
any). Note that setting a limit does not prevent larger factors
from being found early; it simply means that the largest factor may
be composite. Since checking for perfect power is relatively cheap, it is
done regardless of the limit setting.
This number, for example, has two small factors and a huge
semi-prime factor that cannot be reduced easily:
>>> from sympy.ntheory import isprime
>>> from sympy.core.compatibility import long
>>> a = 1407633717262338957430697921446883
>>> f = factorint(a, limit=10000)
>>> f == {991: 1, long(202916782076162456022877024859): 1, 7: 1}
True
>>> isprime(max(f))
False
This number has a small factor and a residual perfect power whose
base is greater than the limit:
>>> factorint(3*101**7, limit=5)
{3: 1, 101: 7}
List of Factors:
If ``multiple`` is set to ``True`` then a list containing the
prime factors including multiplicities is returned.
>>> factorint(24, multiple=True)
[2, 2, 2, 3]
Visual Factorization:
If ``visual`` is set to ``True``, then it will return a visual
factorization of the integer. For example:
>>> from sympy import pprint
>>> pprint(factorint(4200, visual=True))
3 1 2 1
2 *3 *5 *7
Note that this is achieved by using the evaluate=False flag in Mul
and Pow. If you do other manipulations with an expression where
evaluate=False, it may evaluate. Therefore, you should use the
visual option only for visualization, and use the normal dictionary
returned by visual=False if you want to perform operations on the
factors.
You can easily switch between the two forms by sending them back to
factorint:
>>> from sympy import Mul, Pow
>>> regular = factorint(1764); regular
{2: 2, 3: 2, 7: 2}
>>> pprint(factorint(regular))
2 2 2
2 *3 *7
>>> visual = factorint(1764, visual=True); pprint(visual)
2 2 2
2 *3 *7
>>> print(factorint(visual))
{2: 2, 3: 2, 7: 2}
If you want to send a number to be factored in a partially factored form
you can do so with a dictionary or unevaluated expression:
>>> factorint(factorint({4: 2, 12: 3})) # twice to toggle to dict form
{2: 10, 3: 3}
>>> factorint(Mul(4, 12, evaluate=False))
{2: 4, 3: 1}
The table of the output logic is:
====== ====== ======= =======
Visual
------ ----------------------
Input True False other
====== ====== ======= =======
dict mul dict mul
n mul dict dict
mul mul dict dict
====== ====== ======= =======
Notes
=====
Algorithm:
The function switches between multiple algorithms. Trial division
quickly finds small factors (of the order 1-5 digits), and finds
all large factors if given enough time. The Pollard rho and p-1
algorithms are used to find large factors ahead of time; they
will often find factors of the order of 10 digits within a few
seconds:
>>> factors = factorint(12345678910111213141516)
>>> for base, exp in sorted(factors.items()):
... print('%s %s' % (base, exp))
...
2 2
2507191691 1
1231026625769 1
Any of these methods can optionally be disabled with the following
boolean parameters:
- ``use_trial``: Toggle use of trial division
- ``use_rho``: Toggle use of Pollard's rho method
- ``use_pm1``: Toggle use of Pollard's p-1 method
``factorint`` also periodically checks if the remaining part is
a prime number or a perfect power, and in those cases stops.
For unevaluated factorial, it uses Legendre's formula(theorem).
If ``verbose`` is set to ``True``, detailed progress is printed.
See Also
========
smoothness, smoothness_p, divisors
"""
if multiple:
fac = factorint(n, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False, multiple=False)
factorlist = sum(([p] * fac[p] if fac[p] > 0 else [S(1)/p]*(-fac[p])
for p in sorted(fac)), [])
return factorlist
factordict = {}
if visual and not isinstance(n, Mul) and not isinstance(n, dict):
factordict = factorint(n, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False)
elif isinstance(n, Mul):
factordict = dict([(int(k), int(v)) for k, v in
list(n.as_powers_dict().items())])
elif isinstance(n, dict):
factordict = n
if factordict and (isinstance(n, Mul) or isinstance(n, dict)):
# check it
for k in list(factordict.keys()):
if isprime(k):
continue
e = factordict.pop(k)
d = factorint(k, limit=limit, use_trial=use_trial, use_rho=use_rho,
use_pm1=use_pm1, verbose=verbose, visual=False)
for k, v in d.items():
if k in factordict:
factordict[k] += v*e
else:
factordict[k] = v*e
if visual or (type(n) is dict and
visual is not True and
visual is not False):
if factordict == {}:
return S.One
if -1 in factordict:
factordict.pop(-1)
args = [S.NegativeOne]
else:
args = []
args.extend([Pow(*i, evaluate=False)
for i in sorted(factordict.items())])
return Mul(*args, evaluate=False)
elif isinstance(n, dict) or isinstance(n, Mul):
return factordict
assert use_trial or use_rho or use_pm1
from sympy.functions.combinatorial.factorials import factorial
if isinstance(n, factorial):
x = as_int(n.args[0])
if x >= 20:
factors = {}
m = 2 # to initialize the if condition below
for p in sieve.primerange(2, x + 1):
if m > 1:
m, q = 0, x // p
while q != 0:
m += q
q //= p
factors[p] = m
if factors and verbose:
for k in sorted(factors):
print(factor_msg % (k, factors[k]))
if verbose:
print(complete_msg)
return factors
else:
# if n < 20!, direct computation is faster
# since it uses a lookup table
n = n.func(x)
n = as_int(n)
if limit:
limit = int(limit)
# special cases
if n < 0:
factors = factorint(
-n, limit=limit, use_trial=use_trial, use_rho=use_rho,
use_pm1=use_pm1, verbose=verbose, visual=False)
factors[-1] = 1
return factors
if limit and limit < 2:
if n == 1:
return {}
return {n: 1}
elif n < 10:
# doing this we are assured of getting a limit > 2
# when we have to compute it later
return [{0: 1}, {}, {2: 1}, {3: 1}, {2: 2}, {5: 1},
{2: 1, 3: 1}, {7: 1}, {2: 3}, {3: 2}][n]
factors = {}
# do simplistic factorization
if verbose:
sn = str(n)
if len(sn) > 50:
print('Factoring %s' % sn[:5] + \
'..(%i other digits)..' % (len(sn) - 10) + sn[-5:])
else:
print('Factoring', n)
if use_trial:
# this is the preliminary factorization for small factors
small = 2**15
fail_max = 600
small = min(small, limit or small)
if verbose:
print(trial_int_msg % (2, small, fail_max))
n, next_p = _factorint_small(factors, n, small, fail_max)
else:
next_p = 2
if factors and verbose:
for k in sorted(factors):
print(factor_msg % (k, factors[k]))
if next_p == 0:
if n > 1:
factors[int(n)] = 1
if verbose:
print(complete_msg)
return factors
# continue with more advanced factorization methods
# first check if the simplistic run didn't finish
# because of the limit and check for a perfect
# power before exiting
try:
if limit and next_p > limit:
if verbose:
print('Exceeded limit:', limit)
_check_termination(factors, n, limit, use_trial, use_rho, use_pm1,
verbose)
if n > 1:
factors[int(n)] = 1
return factors
else:
# Before quitting (or continuing on)...
# ...do a Fermat test since it's so easy and we need the
# square root anyway. Finding 2 factors is easy if they are
# "close enough." This is the big root equivalent of dividing by
# 2, 3, 5.
sqrt_n = integer_nthroot(n, 2)[0]
a = sqrt_n + 1
a2 = a**2
b2 = a2 - n
for i in range(3):
b, fermat = integer_nthroot(b2, 2)
if fermat:
break
b2 += 2*a + 1 # equiv to (a + 1)**2 - n
a += 1
if fermat:
if verbose:
print(fermat_msg)
if limit:
limit -= 1
for r in [a - b, a + b]:
facs = factorint(r, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose)
factors.update(facs)
raise StopIteration
# ...see if factorization can be terminated
_check_termination(factors, n, limit, use_trial, use_rho, use_pm1,
verbose)
except StopIteration:
if verbose:
print(complete_msg)
return factors
# these are the limits for trial division which will
# be attempted in parallel with pollard methods
low, high = next_p, 2*next_p
limit = limit or sqrt_n
# add 1 to make sure limit is reached in primerange calls
limit += 1
while 1:
try:
high_ = high
if limit < high_:
high_ = limit
# Trial division
if use_trial:
if verbose:
print(trial_msg % (low, high_))
ps = sieve.primerange(low, high_)
n, found_trial = _trial(factors, n, ps, verbose)
if found_trial:
_check_termination(factors, n, limit, use_trial, use_rho,
use_pm1, verbose)
else:
found_trial = False
if high > limit:
if verbose:
print('Exceeded limit:', limit)
if n > 1:
factors[int(n)] = 1
raise StopIteration
# Only used advanced methods when no small factors were found
if not found_trial:
if (use_pm1 or use_rho):
high_root = max(int(math.log(high_**0.7)), low, 3)
# Pollard p-1
if use_pm1:
if verbose:
print(pm1_msg % (high_root, high_))
c = pollard_pm1(n, B=high_root, seed=high_)
if c:
# factor it and let _trial do the update
ps = factorint(c, limit=limit - 1,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
verbose=verbose)
n, _ = _trial(factors, n, ps, verbose=False)
_check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose)
# Pollard rho
if use_rho:
max_steps = high_root
if verbose:
print(rho_msg % (1, max_steps, high_))
c = pollard_rho(n, retries=1, max_steps=max_steps,
seed=high_)
if c:
# factor it and let _trial do the update
ps = factorint(c, limit=limit - 1,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
verbose=verbose)
n, _ = _trial(factors, n, ps, verbose=False)
_check_termination(factors, n, limit, use_trial,
use_rho, use_pm1, verbose)
except StopIteration:
if verbose:
print(complete_msg)
return factors
low, high = high, high*2
def factorrat(rat, limit=None, use_trial=True, use_rho=True, use_pm1=True,
verbose=False, visual=None, multiple=False):
r"""
Given a Rational ``r``, ``factorrat(r)`` returns a dict containing
the prime factors of ``r`` as keys and their respective multiplicities
as values. For example:
>>> from sympy.ntheory import factorrat
>>> from sympy.core.symbol import S
>>> factorrat(S(8)/9) # 8/9 = (2**3) * (3**-2)
{2: 3, 3: -2}
>>> factorrat(S(-1)/987) # -1/789 = -1 * (3**-1) * (7**-1) * (47**-1)
{-1: 1, 3: -1, 7: -1, 47: -1}
Please see the docstring for ``factorint`` for detailed explanations
and examples of the following keywords:
- ``limit``: Integer limit up to which trial division is done
- ``use_trial``: Toggle use of trial division
- ``use_rho``: Toggle use of Pollard's rho method
- ``use_pm1``: Toggle use of Pollard's p-1 method
- ``verbose``: Toggle detailed printing of progress
- ``multiple``: Toggle returning a list of factors or dict
- ``visual``: Toggle product form of output
"""
from collections import defaultdict
if multiple:
fac = factorrat(rat, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose, visual=False, multiple=False)
factorlist = sum(([p] * fac[p] if fac[p] > 0 else [S(1)/p]*(-fac[p])
for p, _ in sorted(fac.items(),
key=lambda elem: elem[0]
if elem[1] > 0
else 1/elem[0])), [])
return factorlist
f = factorint(rat.p, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose).copy()
f = defaultdict(int, f)
for p, e in factorint(rat.q, limit=limit,
use_trial=use_trial,
use_rho=use_rho,
use_pm1=use_pm1,
verbose=verbose).items():
f[p] += -e
if len(f) > 1 and 1 in f:
del f[1]
if not visual:
return dict(f)
else:
if -1 in f:
f.pop(-1)
args = [S.NegativeOne]
else:
args = []
args.extend([Pow(*i, evaluate=False)
for i in sorted(f.items())])
return Mul(*args, evaluate=False)
def primefactors(n, limit=None, verbose=False):
"""Return a sorted list of n's prime factors, ignoring multiplicity
and any composite factor that remains if the limit was set too low
for complete factorization. Unlike factorint(), primefactors() does
not return -1 or 0.
Examples
========
>>> from sympy.ntheory import primefactors, factorint, isprime
>>> primefactors(6)
[2, 3]
>>> primefactors(-5)
[5]
>>> sorted(factorint(123456).items())
[(2, 6), (3, 1), (643, 1)]
>>> primefactors(123456)
[2, 3, 643]
>>> sorted(factorint(10000000001, limit=200).items())
[(101, 1), (99009901, 1)]
>>> isprime(99009901)
False
>>> primefactors(10000000001, limit=300)
[101]
See Also
========
divisors
"""
n = int(n)
factors = sorted(factorint(n, limit=limit, verbose=verbose).keys())
s = [f for f in factors[:-1:] if f not in [-1, 0, 1]]
if factors and isprime(factors[-1]):
s += [factors[-1]]
return s
def _divisors(n):
"""Helper function for divisors which generates the divisors."""
factordict = factorint(n)
ps = sorted(factordict.keys())
def rec_gen(n=0):
if n == len(ps):
yield 1
else:
pows = [1]
for j in range(factordict[ps[n]]):
pows.append(pows[-1] * ps[n])
for q in rec_gen(n + 1):
for p in pows:
yield p * q
for p in rec_gen():
yield p
def divisors(n, generator=False):
r"""
Return all divisors of n sorted from 1..n by default.
If generator is ``True`` an unordered generator is returned.
The number of divisors of n can be quite large if there are many
prime factors (counting repeated factors). If only the number of
factors is desired use divisor_count(n).
Examples
========
>>> from sympy import divisors, divisor_count
>>> divisors(24)
[1, 2, 3, 4, 6, 8, 12, 24]
>>> divisor_count(24)
8
>>> list(divisors(120, generator=True))
[1, 2, 4, 8, 3, 6, 12, 24, 5, 10, 20, 40, 15, 30, 60, 120]
This is a slightly modified version of Tim Peters referenced at:
https://stackoverflow.com/questions/1010381/python-factorization
See Also
========
primefactors, factorint, divisor_count
"""
n = as_int(abs(n))
if isprime(n):
return [1, n]
if n == 1:
return [1]
if n == 0:
return []
rv = _divisors(n)
if not generator:
return sorted(rv)
return rv
def divisor_count(n, modulus=1):
"""
Return the number of divisors of ``n``. If ``modulus`` is not 1 then only
those that are divisible by ``modulus`` are counted.
References
==========
- http://www.mayer.dial.pipex.com/maths/formulae.htm
>>> from sympy import divisor_count
>>> divisor_count(6)
4
See Also
========
factorint, divisors, totient
"""
if not modulus:
return 0
elif modulus != 1:
n, r = divmod(n, modulus)
if r:
return 0
if n == 0:
return 0
return Mul(*[v + 1 for k, v in factorint(n).items() if k > 1])
def _udivisors(n):
"""Helper function for udivisors which generates the unitary divisors."""
factorpows = [p**e for p, e in factorint(n).items()]
for i in range(2**len(factorpows)):
d, j, k = 1, i, 0
while j:
if (j & 1):
d *= factorpows[k]
j >>= 1
k += 1
yield d
def udivisors(n, generator=False):
r"""
Return all unitary divisors of n sorted from 1..n by default.
If generator is ``True`` an unordered generator is returned.
The number of unitary divisors of n can be quite large if there are many
prime factors. If only the number of unitary divisors is desired use
udivisor_count(n).
References
==========
- https://en.wikipedia.org/wiki/Unitary_divisor
- http://mathworld.wolfram.com/UnitaryDivisor.html
Examples
========
>>> from sympy.ntheory.factor_ import udivisors, udivisor_count
>>> udivisors(15)
[1, 3, 5, 15]
>>> udivisor_count(15)
4
>>> sorted(udivisors(120, generator=True))
[1, 3, 5, 8, 15, 24, 40, 120]
See Also
========
primefactors, factorint, divisors, divisor_count, udivisor_count
"""
n = as_int(abs(n))
if isprime(n):
return [1, n]
if n == 1:
return [1]
if n == 0:
return []
rv = _udivisors(n)
if not generator:
return sorted(rv)
return rv
def udivisor_count(n):
"""
Return the number of unitary divisors of ``n``.
References
==========
- http://mathworld.wolfram.com/UnitaryDivisorFunction.html
>>> from sympy.ntheory.factor_ import udivisor_count
>>> udivisor_count(120)
8
See Also
========
factorint, divisors, udivisors, divisor_count, totient
"""
if n == 0:
return 0
return 2**len([p for p in factorint(n) if p > 1])
def _antidivisors(n):
"""Helper function for antidivisors which generates the antidivisors."""
for d in _divisors(n):
y = 2*d
if n > y and n % y:
yield y
for d in _divisors(2*n-1):
if n > d >= 2 and n % d:
yield d
for d in _divisors(2*n+1):
if n > d >= 2 and n % d:
yield d
def antidivisors(n, generator=False):
r"""
Return all antidivisors of n sorted from 1..n by default.
Antidivisors [1]_ of n are numbers that do not divide n by the largest
possible margin. If generator is True an unordered generator is returned.
References
==========
.. [1] definition is described in https://oeis.org/A066272/a066272a.html
Examples
========
>>> from sympy.ntheory.factor_ import antidivisors
>>> antidivisors(24)
[7, 16]
>>> sorted(antidivisors(128, generator=True))
[3, 5, 15, 17, 51, 85]
See Also
========
primefactors, factorint, divisors, divisor_count, antidivisor_count
"""
n = as_int(abs(n))
if n <= 2:
return []
rv = _antidivisors(n)
if not generator:
return sorted(rv)
return rv
def antidivisor_count(n):
"""
Return the number of antidivisors [1]_ of ``n``.
References
==========
.. [1] formula from https://oeis.org/A066272
Examples
========
>>> from sympy.ntheory.factor_ import antidivisor_count
>>> antidivisor_count(13)
4
>>> antidivisor_count(27)
5
See Also
========
factorint, divisors, antidivisors, divisor_count, totient
"""
n = as_int(abs(n))
if n <= 2:
return 0
return divisor_count(2*n - 1) + divisor_count(2*n + 1) + \
divisor_count(n) - divisor_count(n, 2) - 5
class totient(Function):
r"""
Calculate the Euler totient function phi(n)
``totient(n)`` or `\phi(n)` is the number of positive integers `\leq` n
that are relatively prime to n.
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%27s_totient_function
.. [2] http://mathworld.wolfram.com/TotientFunction.html
Examples
========
>>> from sympy.ntheory import totient
>>> totient(1)
1
>>> totient(25)
20
See Also
========
divisor_count
"""
@classmethod
def eval(cls, n):
n = sympify(n)
if n.is_Integer:
if n < 1:
raise ValueError("n must be a positive integer")
factors = factorint(n)
t = 1
for p, k in factors.items():
t *= (p - 1) * p**(k - 1)
return t
elif not isinstance(n, Expr) or (n.is_integer is False) or (n.is_positive is False):
raise ValueError("n must be a positive integer")
def _eval_is_integer(self):
return fuzzy_and([self.args[0].is_integer, self.args[0].is_positive])
class reduced_totient(Function):
r"""
Calculate the Carmichael reduced totient function lambda(n)
``reduced_totient(n)`` or `\lambda(n)` is the smallest m > 0 such that
`k^m \equiv 1 \mod n` for all k relatively prime to n.
References
==========
.. [1] https://en.wikipedia.org/wiki/Carmichael_function
.. [2] http://mathworld.wolfram.com/CarmichaelFunction.html
Examples
========
>>> from sympy.ntheory import reduced_totient
>>> reduced_totient(1)
1
>>> reduced_totient(8)
2
>>> reduced_totient(30)
4
See Also
========
totient
"""
@classmethod
def eval(cls, n):
n = sympify(n)
if n.is_Integer:
if n < 1:
raise ValueError("n must be a positive integer")
factors = factorint(n)
t = 1
for p, k in factors.items():
if p == 2 and k > 2:
t = ilcm(t, 2**(k - 2))
else:
t = ilcm(t, (p - 1) * p**(k - 1))
return t
def _eval_is_integer(self):
return fuzzy_and([self.args[0].is_integer, self.args[0].is_positive])
class divisor_sigma(Function):
r"""
Calculate the divisor function `\sigma_k(n)` for positive integer n
``divisor_sigma(n, k)`` is equal to ``sum([x**k for x in divisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k(n) = \prod_{i=1}^\omega (1+p_i^k+p_i^{2k}+\cdots
+ p_i^{m_ik}).
Parameters
==========
k : power of divisors in the sum
for k = 0, 1:
``divisor_sigma(n, 0)`` is equal to ``divisor_count(n)``
``divisor_sigma(n, 1)`` is equal to ``sum(divisors(n))``
Default for k is 1.
References
==========
.. [1] https://en.wikipedia.org/wiki/Divisor_function
Examples
========
>>> from sympy.ntheory import divisor_sigma
>>> divisor_sigma(18, 0)
6
>>> divisor_sigma(39, 1)
56
>>> divisor_sigma(12, 2)
210
>>> divisor_sigma(37)
38
See Also
========
divisor_count, totient, divisors, factorint
"""
@classmethod
def eval(cls, n, k=1):
n = sympify(n)
k = sympify(k)
if n.is_prime:
return 1 + n**k
if n.is_Integer:
if n <= 0:
raise ValueError("n must be a positive integer")
else:
return Mul(*[(p**(k*(e + 1)) - 1)/(p**k - 1) if k != 0
else e + 1 for p, e in factorint(n).items()])
def core(n, t=2):
r"""
Calculate core(n, t) = `core_t(n)` of a positive integer n
``core_2(n)`` is equal to the squarefree part of n
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
core_t(n) = \prod_{i=1}^\omega p_i^{m_i \mod t}.
Parameters
==========
t : core(n, t) calculates the t-th power free part of n
``core(n, 2)`` is the squarefree part of ``n``
``core(n, 3)`` is the cubefree part of ``n``
Default for t is 2.
References
==========
.. [1] https://en.wikipedia.org/wiki/Square-free_integer#Squarefree_core
Examples
========
>>> from sympy.ntheory.factor_ import core
>>> core(24, 2)
6
>>> core(9424, 3)
1178
>>> core(379238)
379238
>>> core(15**11, 10)
15
See Also
========
factorint, sympy.solvers.diophantine.square_factor
"""
n = as_int(n)
t = as_int(t)
if n <= 0:
raise ValueError("n must be a positive integer")
elif t <= 1:
raise ValueError("t must be >= 2")
else:
y = 1
for p, e in factorint(n).items():
y *= p**(e % t)
return y
def digits(n, b=10):
"""
Return a list of the digits of n in base b. The first element in the list
is b (or -b if n is negative).
Examples
========
>>> from sympy.ntheory.factor_ import digits
>>> digits(35)
[10, 3, 5]
>>> digits(27, 2)
[2, 1, 1, 0, 1, 1]
>>> digits(65536, 256)
[256, 1, 0, 0]
>>> digits(-3958, 27)
[-27, 5, 11, 16]
"""
b = as_int(b)
n = as_int(n)
if b <= 1:
raise ValueError("b must be >= 2")
else:
x, y = abs(n), []
while x >= b:
x, r = divmod(x, b)
y.append(r)
y.append(x)
y.append(-b if n < 0 else b)
y.reverse()
return y
class udivisor_sigma(Function):
r"""
Calculate the unitary divisor function `\sigma_k^*(n)` for positive integer n
``udivisor_sigma(n, k)`` is equal to ``sum([x**k for x in udivisors(n)])``
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^\omega p_i^{m_i},
then
.. math ::
\sigma_k^*(n) = \prod_{i=1}^\omega (1+ p_i^{m_ik}).
Parameters
==========
k : power of divisors in the sum
for k = 0, 1:
``udivisor_sigma(n, 0)`` is equal to ``udivisor_count(n)``
``udivisor_sigma(n, 1)`` is equal to ``sum(udivisors(n))``
Default for k is 1.
References
==========
.. [1] http://mathworld.wolfram.com/UnitaryDivisorFunction.html
Examples
========
>>> from sympy.ntheory.factor_ import udivisor_sigma
>>> udivisor_sigma(18, 0)
4
>>> udivisor_sigma(74, 1)
114
>>> udivisor_sigma(36, 3)
47450
>>> udivisor_sigma(111)
152
See Also
========
divisor_count, totient, divisors, udivisors, udivisor_count, divisor_sigma,
factorint
"""
@classmethod
def eval(cls, n, k=1):
n = sympify(n)
k = sympify(k)
if n.is_prime:
return 1 + n**k
if n.is_Integer:
if n <= 0:
raise ValueError("n must be a positive integer")
else:
return Mul(*[1+p**(k*e) for p, e in factorint(n).items()])
class primenu(Function):
r"""
Calculate the number of distinct prime factors for a positive integer n.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primenu(n)`` or `\nu(n)` is:
.. math ::
\nu(n) = k.
References
==========
.. [1] http://mathworld.wolfram.com/PrimeFactor.html
Examples
========
>>> from sympy.ntheory.factor_ import primenu
>>> primenu(1)
0
>>> primenu(30)
3
See Also
========
factorint
"""
@classmethod
def eval(cls, n):
n = sympify(n)
if n.is_Integer:
if n <= 0:
raise ValueError("n must be a positive integer")
else:
return len(factorint(n).keys())
class primeomega(Function):
r"""
Calculate the number of prime factors counting multiplicities for a
positive integer n.
If n's prime factorization is:
.. math ::
n = \prod_{i=1}^k p_i^{m_i},
then ``primeomega(n)`` or `\Omega(n)` is:
.. math ::
\Omega(n) = \sum_{i=1}^k m_i.
References
==========
.. [1] http://mathworld.wolfram.com/PrimeFactor.html
Examples
========
>>> from sympy.ntheory.factor_ import primeomega
>>> primeomega(1)
0
>>> primeomega(20)
3
See Also
========
factorint
"""
@classmethod
def eval(cls, n):
n = sympify(n)
if n.is_Integer:
if n <= 0:
raise ValueError("n must be a positive integer")
else:
return sum(factorint(n).values())
|
5fee436b0994ad1d3c8ee01b6132133d7552b682217810c31b65a83adab68ffd
|
from __future__ import print_function, division
import random
from collections import defaultdict
from sympy.core import Basic
from sympy.core.compatibility import is_sequence, reduce, range, as_int
from sympy.utilities.iterables import (flatten, has_variety, minlex,
has_dups, runs)
from sympy.polys.polytools import lcm
from sympy.matrices import zeros
from mpmath.libmp.libintmath import ifac
def _af_rmul(a, b):
"""
Return the product b*a; input and output are array forms. The ith value
is a[b[i]].
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> Permutation.print_cyclic = False
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> _af_rmul(a, b)
[1, 2, 0]
>>> [a[b[i]] for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a)
>>> b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
See Also
========
rmul, _af_rmuln
"""
return [a[i] for i in b]
def _af_rmuln(*abc):
"""
Given [a, b, c, ...] return the product of ...*c*b*a using array forms.
The ith value is a[b[c[i]]].
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> Permutation.print_cyclic = False
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> _af_rmul(a, b)
[1, 2, 0]
>>> [a[b[i]] for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
See Also
========
rmul, _af_rmul
"""
a = abc
m = len(a)
if m == 3:
p0, p1, p2 = a
return [p0[p1[i]] for i in p2]
if m == 4:
p0, p1, p2, p3 = a
return [p0[p1[p2[i]]] for i in p3]
if m == 5:
p0, p1, p2, p3, p4 = a
return [p0[p1[p2[p3[i]]]] for i in p4]
if m == 6:
p0, p1, p2, p3, p4, p5 = a
return [p0[p1[p2[p3[p4[i]]]]] for i in p5]
if m == 7:
p0, p1, p2, p3, p4, p5, p6 = a
return [p0[p1[p2[p3[p4[p5[i]]]]]] for i in p6]
if m == 8:
p0, p1, p2, p3, p4, p5, p6, p7 = a
return [p0[p1[p2[p3[p4[p5[p6[i]]]]]]] for i in p7]
if m == 1:
return a[0][:]
if m == 2:
a, b = a
return [a[i] for i in b]
if m == 0:
raise ValueError("String must not be empty")
p0 = _af_rmuln(*a[:m//2])
p1 = _af_rmuln(*a[m//2:])
return [p0[i] for i in p1]
def _af_parity(pi):
"""
Computes the parity of a permutation in array form.
The parity of a permutation reflects the parity of the
number of inversions in the permutation, i.e., the
number of pairs of x and y such that x > y but p[x] < p[y].
Examples
========
>>> from sympy.combinatorics.permutations import _af_parity
>>> _af_parity([0, 1, 2, 3])
0
>>> _af_parity([3, 2, 0, 1])
1
See Also
========
Permutation
"""
n = len(pi)
a = [0] * n
c = 0
for j in range(n):
if a[j] == 0:
c += 1
a[j] = 1
i = j
while pi[i] != j:
i = pi[i]
a[i] = 1
return (n - c) % 2
def _af_invert(a):
"""
Finds the inverse, ~A, of a permutation, A, given in array form.
Examples
========
>>> from sympy.combinatorics.permutations import _af_invert, _af_rmul
>>> A = [1, 2, 0, 3]
>>> _af_invert(A)
[2, 0, 1, 3]
>>> _af_rmul(_, A)
[0, 1, 2, 3]
See Also
========
Permutation, __invert__
"""
inv_form = [0] * len(a)
for i, ai in enumerate(a):
inv_form[ai] = i
return inv_form
def _af_pow(a, n):
"""
Routine for finding powers of a permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation, _af_pow
>>> Permutation.print_cyclic = False
>>> p = Permutation([2, 0, 3, 1])
>>> p.order()
4
>>> _af_pow(p._array_form, 4)
[0, 1, 2, 3]
"""
if n == 0:
return list(range(len(a)))
if n < 0:
return _af_pow(_af_invert(a), -n)
if n == 1:
return a[:]
elif n == 2:
b = [a[i] for i in a]
elif n == 3:
b = [a[a[i]] for i in a]
elif n == 4:
b = [a[a[a[i]]] for i in a]
else:
# use binary multiplication
b = list(range(len(a)))
while 1:
if n & 1:
b = [b[i] for i in a]
n -= 1
if not n:
break
if n % 4 == 0:
a = [a[a[a[i]]] for i in a]
n = n // 4
elif n % 2 == 0:
a = [a[i] for i in a]
n = n // 2
return b
def _af_commutes_with(a, b):
"""
Checks if the two permutations with array forms
given by ``a`` and ``b`` commute.
Examples
========
>>> from sympy.combinatorics.permutations import _af_commutes_with
>>> _af_commutes_with([1, 2, 0], [0, 2, 1])
False
See Also
========
Permutation, commutes_with
"""
return not any(a[b[i]] != b[a[i]] for i in range(len(a) - 1))
class Cycle(dict):
"""
Wrapper around dict which provides the functionality of a disjoint cycle.
A cycle shows the rule to use to move subsets of elements to obtain
a permutation. The Cycle class is more flexible than Permutation in
that 1) all elements need not be present in order to investigate how
multiple cycles act in sequence and 2) it can contain singletons:
>>> from sympy.combinatorics.permutations import Perm, Cycle
A Cycle will automatically parse a cycle given as a tuple on the rhs:
>>> Cycle(1, 2)(2, 3)
(1 3 2)
The identity cycle, Cycle(), can be used to start a product:
>>> Cycle()(1, 2)(2, 3)
(1 3 2)
The array form of a Cycle can be obtained by calling the list
method (or passing it to the list function) and all elements from
0 will be shown:
>>> a = Cycle(1, 2)
>>> a.list()
[0, 2, 1]
>>> list(a)
[0, 2, 1]
If a larger (or smaller) range is desired use the list method and
provide the desired size -- but the Cycle cannot be truncated to
a size smaller than the largest element that is out of place:
>>> b = Cycle(2, 4)(1, 2)(3, 1, 4)(1, 3)
>>> b.list()
[0, 2, 1, 3, 4]
>>> b.list(b.size + 1)
[0, 2, 1, 3, 4, 5]
>>> b.list(-1)
[0, 2, 1]
Singletons are not shown when printing with one exception: the largest
element is always shown -- as a singleton if necessary:
>>> Cycle(1, 4, 10)(4, 5)
(1 5 4 10)
>>> Cycle(1, 2)(4)(5)(10)
(1 2)(10)
The array form can be used to instantiate a Permutation so other
properties of the permutation can be investigated:
>>> Perm(Cycle(1, 2)(3, 4).list()).transpositions()
[(1, 2), (3, 4)]
Notes
=====
The underlying structure of the Cycle is a dictionary and although
the __iter__ method has been redefined to give the array form of the
cycle, the underlying dictionary items are still available with the
such methods as items():
>>> list(Cycle(1, 2).items())
[(1, 2), (2, 1)]
See Also
========
Permutation
"""
def __missing__(self, arg):
"""Enter arg into dictionary and return arg."""
arg = as_int(arg)
self[arg] = arg
return arg
def __iter__(self):
for i in self.list():
yield i
def __call__(self, *other):
"""Return product of cycles processed from R to L.
Examples
========
>>> from sympy.combinatorics.permutations import Cycle as C
>>> from sympy.combinatorics.permutations import Permutation as Perm
>>> C(1, 2)(2, 3)
(1 3 2)
An instance of a Cycle will automatically parse list-like
objects and Permutations that are on the right. It is more
flexible than the Permutation in that all elements need not
be present:
>>> a = C(1, 2)
>>> a(2, 3)
(1 3 2)
>>> a(2, 3)(4, 5)
(1 3 2)(4 5)
"""
rv = Cycle(*other)
for k, v in zip(list(self.keys()), [rv[self[k]] for k in self.keys()]):
rv[k] = v
return rv
def list(self, size=None):
"""Return the cycles as an explicit list starting from 0 up
to the greater of the largest value in the cycles and size.
Truncation of trailing unmoved items will occur when size
is less than the maximum element in the cycle; if this is
desired, setting ``size=-1`` will guarantee such trimming.
Examples
========
>>> from sympy.combinatorics.permutations import Cycle
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Cycle(2, 3)(4, 5)
>>> p.list()
[0, 1, 3, 2, 5, 4]
>>> p.list(10)
[0, 1, 3, 2, 5, 4, 6, 7, 8, 9]
Passing a length too small will trim trailing, unchanged elements
in the permutation:
>>> Cycle(2, 4)(1, 2, 4).list(-1)
[0, 2, 1]
"""
if not self and size is None:
raise ValueError('must give size for empty Cycle')
if size is not None:
big = max([i for i in self.keys() if self[i] != i] + [0])
size = max(size, big + 1)
else:
size = self.size
return [self[i] for i in range(size)]
def __repr__(self):
"""We want it to print as a Cycle, not as a dict.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2)
(1 2)
>>> print(_)
(1 2)
>>> list(Cycle(1, 2).items())
[(1, 2), (2, 1)]
"""
if not self:
return 'Cycle()'
cycles = Permutation(self).cyclic_form
s = ''.join(str(tuple(c)) for c in cycles)
big = self.size - 1
if not any(i == big for c in cycles for i in c):
s += '(%s)' % big
return 'Cycle%s' % s
def __str__(self):
"""We want it to be printed in a Cycle notation with no
comma in-between.
Examples
========
>>> from sympy.combinatorics import Cycle
>>> Cycle(1, 2)
(1 2)
>>> Cycle(1, 2, 4)(5, 6)
(1 2 4)(5 6)
"""
if not self:
return '()'
cycles = Permutation(self).cyclic_form
s = ''.join(str(tuple(c)) for c in cycles)
big = self.size - 1
if not any(i == big for c in cycles for i in c):
s += '(%s)' % big
s = s.replace(',', '')
return s
def __init__(self, *args):
"""Load up a Cycle instance with the values for the cycle.
Examples
========
>>> from sympy.combinatorics.permutations import Cycle
>>> Cycle(1, 2, 6)
(1 2 6)
"""
if not args:
return
if len(args) == 1:
if isinstance(args[0], Permutation):
for c in args[0].cyclic_form:
self.update(self(*c))
return
elif isinstance(args[0], Cycle):
for k, v in args[0].items():
self[k] = v
return
args = [as_int(a) for a in args]
if any(i < 0 for i in args):
raise ValueError('negative integers are not allowed in a cycle.')
if has_dups(args):
raise ValueError('All elements must be unique in a cycle.')
for i in range(-len(args), 0):
self[args[i]] = args[i + 1]
@property
def size(self):
if not self:
return 0
return max(self.keys()) + 1
def copy(self):
return Cycle(self)
class Permutation(Basic):
"""
A permutation, alternatively known as an 'arrangement number' or 'ordering'
is an arrangement of the elements of an ordered list into a one-to-one
mapping with itself. The permutation of a given arrangement is given by
indicating the positions of the elements after re-arrangement [2]_. For
example, if one started with elements [x, y, a, b] (in that order) and
they were reordered as [x, y, b, a] then the permutation would be
[0, 1, 3, 2]. Notice that (in SymPy) the first element is always referred
to as 0 and the permutation uses the indices of the elements in the
original ordering, not the elements (a, b, etc...) themselves.
>>> from sympy.combinatorics import Permutation
>>> Permutation.print_cyclic = False
Permutations Notation
=====================
Permutations are commonly represented in disjoint cycle or array forms.
Array Notation and 2-line Form
------------------------------------
In the 2-line form, the elements and their final positions are shown
as a matrix with 2 rows:
[0 1 2 ... n-1]
[p(0) p(1) p(2) ... p(n-1)]
Since the first line is always range(n), where n is the size of p,
it is sufficient to represent the permutation by the second line,
referred to as the "array form" of the permutation. This is entered
in brackets as the argument to the Permutation class:
>>> p = Permutation([0, 2, 1]); p
Permutation([0, 2, 1])
Given i in range(p.size), the permutation maps i to i^p
>>> [i^p for i in range(p.size)]
[0, 2, 1]
The composite of two permutations p*q means first apply p, then q, so
i^(p*q) = (i^p)^q which is i^p^q according to Python precedence rules:
>>> q = Permutation([2, 1, 0])
>>> [i^p^q for i in range(3)]
[2, 0, 1]
>>> [i^(p*q) for i in range(3)]
[2, 0, 1]
One can use also the notation p(i) = i^p, but then the composition
rule is (p*q)(i) = q(p(i)), not p(q(i)):
>>> [(p*q)(i) for i in range(p.size)]
[2, 0, 1]
>>> [q(p(i)) for i in range(p.size)]
[2, 0, 1]
>>> [p(q(i)) for i in range(p.size)]
[1, 2, 0]
Disjoint Cycle Notation
-----------------------
In disjoint cycle notation, only the elements that have shifted are
indicated. In the above case, the 2 and 1 switched places. This can
be entered in two ways:
>>> Permutation(1, 2) == Permutation([[1, 2]]) == p
True
Only the relative ordering of elements in a cycle matter:
>>> Permutation(1,2,3) == Permutation(2,3,1) == Permutation(3,1,2)
True
The disjoint cycle notation is convenient when representing
permutations that have several cycles in them:
>>> Permutation(1, 2)(3, 5) == Permutation([[1, 2], [3, 5]])
True
It also provides some economy in entry when computing products of
permutations that are written in disjoint cycle notation:
>>> Permutation(1, 2)(1, 3)(2, 3)
Permutation([0, 3, 2, 1])
>>> _ == Permutation([[1, 2]])*Permutation([[1, 3]])*Permutation([[2, 3]])
True
Caution: when the cycles have common elements
between them then the order in which the
permutations are applied matters. The
convention is that the permutations are
applied from *right to left*. In the following, the
transposition of elements 2 and 3 is followed
by the transposition of elements 1 and 2:
>>> Permutation(1, 2)(2, 3) == Permutation([(1, 2), (2, 3)])
True
>>> Permutation(1, 2)(2, 3).list()
[0, 3, 1, 2]
If the first and second elements had been
swapped first, followed by the swapping of the second
and third, the result would have been [0, 2, 3, 1].
If, for some reason, you want to apply the cycles
in the order they are entered, you can simply reverse
the order of cycles:
>>> Permutation([(1, 2), (2, 3)][::-1]).list()
[0, 2, 3, 1]
Entering a singleton in a permutation is a way to indicate the size of the
permutation. The ``size`` keyword can also be used.
Array-form entry:
>>> Permutation([[1, 2], [9]])
Permutation([0, 2, 1], size=10)
>>> Permutation([[1, 2]], size=10)
Permutation([0, 2, 1], size=10)
Cyclic-form entry:
>>> Permutation(1, 2, size=10)
Permutation([0, 2, 1], size=10)
>>> Permutation(9)(1, 2)
Permutation([0, 2, 1], size=10)
Caution: no singleton containing an element larger than the largest
in any previous cycle can be entered. This is an important difference
in how Permutation and Cycle handle the __call__ syntax. A singleton
argument at the start of a Permutation performs instantiation of the
Permutation and is permitted:
>>> Permutation(5)
Permutation([], size=6)
A singleton entered after instantiation is a call to the permutation
-- a function call -- and if the argument is out of range it will
trigger an error. For this reason, it is better to start the cycle
with the singleton:
The following fails because there is is no element 3:
>>> Permutation(1, 2)(3)
Traceback (most recent call last):
...
IndexError: list index out of range
This is ok: only the call to an out of range singleton is prohibited;
otherwise the permutation autosizes:
>>> Permutation(3)(1, 2)
Permutation([0, 2, 1, 3])
>>> Permutation(1, 2)(3, 4) == Permutation(3, 4)(1, 2)
True
Equality testing
----------------
The array forms must be the same in order for permutations to be equal:
>>> Permutation([1, 0, 2, 3]) == Permutation([1, 0])
False
Identity Permutation
--------------------
The identity permutation is a permutation in which no element is out of
place. It can be entered in a variety of ways. All the following create
an identity permutation of size 4:
>>> I = Permutation([0, 1, 2, 3])
>>> all(p == I for p in [
... Permutation(3),
... Permutation(range(4)),
... Permutation([], size=4),
... Permutation(size=4)])
True
Watch out for entering the range *inside* a set of brackets (which is
cycle notation):
>>> I == Permutation([range(4)])
False
Permutation Printing
====================
There are a few things to note about how Permutations are printed.
1) If you prefer one form (array or cycle) over another, you can set that
with the print_cyclic flag.
>>> Permutation(1, 2)(4, 5)(3, 4)
Permutation([0, 2, 1, 4, 5, 3])
>>> p = _
>>> Permutation.print_cyclic = True
>>> p
(1 2)(3 4 5)
>>> Permutation.print_cyclic = False
2) Regardless of the setting, a list of elements in the array for cyclic
form can be obtained and either of those can be copied and supplied as
the argument to Permutation:
>>> p.array_form
[0, 2, 1, 4, 5, 3]
>>> p.cyclic_form
[[1, 2], [3, 4, 5]]
>>> Permutation(_) == p
True
3) Printing is economical in that as little as possible is printed while
retaining all information about the size of the permutation:
>>> Permutation([1, 0, 2, 3])
Permutation([1, 0, 2, 3])
>>> Permutation([1, 0, 2, 3], size=20)
Permutation([1, 0], size=20)
>>> Permutation([1, 0, 2, 4, 3, 5, 6], size=20)
Permutation([1, 0, 2, 4, 3], size=20)
>>> p = Permutation([1, 0, 2, 3])
>>> Permutation.print_cyclic = True
>>> p
(3)(0 1)
>>> Permutation.print_cyclic = False
The 2 was not printed but it is still there as can be seen with the
array_form and size methods:
>>> p.array_form
[1, 0, 2, 3]
>>> p.size
4
Short introduction to other methods
===================================
The permutation can act as a bijective function, telling what element is
located at a given position
>>> q = Permutation([5, 2, 3, 4, 1, 0])
>>> q.array_form[1] # the hard way
2
>>> q(1) # the easy way
2
>>> {i: q(i) for i in range(q.size)} # showing the bijection
{0: 5, 1: 2, 2: 3, 3: 4, 4: 1, 5: 0}
The full cyclic form (including singletons) can be obtained:
>>> p.full_cyclic_form
[[0, 1], [2], [3]]
Any permutation can be factored into transpositions of pairs of elements:
>>> Permutation([[1, 2], [3, 4, 5]]).transpositions()
[(1, 2), (3, 5), (3, 4)]
>>> Permutation.rmul(*[Permutation([ti], size=6) for ti in _]).cyclic_form
[[1, 2], [3, 4, 5]]
The number of permutations on a set of n elements is given by n! and is
called the cardinality.
>>> p.size
4
>>> p.cardinality
24
A given permutation has a rank among all the possible permutations of the
same elements, but what that rank is depends on how the permutations are
enumerated. (There are a number of different methods of doing so.) The
lexicographic rank is given by the rank method and this rank is used to
increment a permutation with addition/subtraction:
>>> p.rank()
6
>>> p + 1
Permutation([1, 0, 3, 2])
>>> p.next_lex()
Permutation([1, 0, 3, 2])
>>> _.rank()
7
>>> p.unrank_lex(p.size, rank=7)
Permutation([1, 0, 3, 2])
The product of two permutations p and q is defined as their composition as
functions, (p*q)(i) = q(p(i)) [6]_.
>>> p = Permutation([1, 0, 2, 3])
>>> q = Permutation([2, 3, 1, 0])
>>> list(q*p)
[2, 3, 0, 1]
>>> list(p*q)
[3, 2, 1, 0]
>>> [q(p(i)) for i in range(p.size)]
[3, 2, 1, 0]
The permutation can be 'applied' to any list-like object, not only
Permutations:
>>> p(['zero', 'one', 'four', 'two'])
['one', 'zero', 'four', 'two']
>>> p('zo42')
['o', 'z', '4', '2']
If you have a list of arbitrary elements, the corresponding permutation
can be found with the from_sequence method:
>>> Permutation.from_sequence('SymPy')
Permutation([1, 3, 2, 0, 4])
See Also
========
Cycle
References
==========
.. [1] Skiena, S. 'Permutations.' 1.1 in Implementing Discrete Mathematics
Combinatorics and Graph Theory with Mathematica. Reading, MA:
Addison-Wesley, pp. 3-16, 1990.
.. [2] Knuth, D. E. The Art of Computer Programming, Vol. 4: Combinatorial
Algorithms, 1st ed. Reading, MA: Addison-Wesley, 2011.
.. [3] Wendy Myrvold and Frank Ruskey. 2001. Ranking and unranking
permutations in linear time. Inf. Process. Lett. 79, 6 (September 2001),
281-284. DOI=10.1016/S0020-0190(01)00141-7
.. [4] D. L. Kreher, D. R. Stinson 'Combinatorial Algorithms'
CRC Press, 1999
.. [5] Graham, R. L.; Knuth, D. E.; and Patashnik, O.
Concrete Mathematics: A Foundation for Computer Science, 2nd ed.
Reading, MA: Addison-Wesley, 1994.
.. [6] https://en.wikipedia.org/wiki/Permutation#Product_and_inverse
.. [7] https://en.wikipedia.org/wiki/Lehmer_code
"""
is_Permutation = True
_array_form = None
_cyclic_form = None
_cycle_structure = None
_size = None
_rank = None
def __new__(cls, *args, **kwargs):
"""
Constructor for the Permutation object from a list or a
list of lists in which all elements of the permutation may
appear only once.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
Permutations entered in array-form are left unaltered:
>>> Permutation([0, 2, 1])
Permutation([0, 2, 1])
Permutations entered in cyclic form are converted to array form;
singletons need not be entered, but can be entered to indicate the
largest element:
>>> Permutation([[4, 5, 6], [0, 1]])
Permutation([1, 0, 2, 3, 5, 6, 4])
>>> Permutation([[4, 5, 6], [0, 1], [19]])
Permutation([1, 0, 2, 3, 5, 6, 4], size=20)
All manipulation of permutations assumes that the smallest element
is 0 (in keeping with 0-based indexing in Python) so if the 0 is
missing when entering a permutation in array form, an error will be
raised:
>>> Permutation([2, 1])
Traceback (most recent call last):
...
ValueError: Integers 0 through 2 must be present.
If a permutation is entered in cyclic form, it can be entered without
singletons and the ``size`` specified so those values can be filled
in, otherwise the array form will only extend to the maximum value
in the cycles:
>>> Permutation([[1, 4], [3, 5, 2]], size=10)
Permutation([0, 4, 3, 5, 1, 2], size=10)
>>> _.array_form
[0, 4, 3, 5, 1, 2, 6, 7, 8, 9]
"""
size = kwargs.pop('size', None)
if size is not None:
size = int(size)
#a) ()
#b) (1) = identity
#c) (1, 2) = cycle
#d) ([1, 2, 3]) = array form
#e) ([[1, 2]]) = cyclic form
#f) (Cycle) = conversion to permutation
#g) (Permutation) = adjust size or return copy
ok = True
if not args: # a
return cls._af_new(list(range(size or 0)))
elif len(args) > 1: # c
return cls._af_new(Cycle(*args).list(size))
if len(args) == 1:
a = args[0]
if isinstance(a, cls): # g
if size is None or size == a.size:
return a
return cls(a.array_form, size=size)
if isinstance(a, Cycle): # f
return cls._af_new(a.list(size))
if not is_sequence(a): # b
return cls._af_new(list(range(a + 1)))
if has_variety(is_sequence(ai) for ai in a):
ok = False
else:
ok = False
if not ok:
raise ValueError("Permutation argument must be a list of ints, "
"a list of lists, Permutation or Cycle.")
# safe to assume args are valid; this also makes a copy
# of the args
args = list(args[0])
is_cycle = args and is_sequence(args[0])
if is_cycle: # e
args = [[int(i) for i in c] for c in args]
else: # d
args = [int(i) for i in args]
# if there are n elements present, 0, 1, ..., n-1 should be present
# unless a cycle notation has been provided. A 0 will be added
# for convenience in case one wants to enter permutations where
# counting starts from 1.
temp = flatten(args)
if has_dups(temp) and not is_cycle:
raise ValueError('there were repeated elements.')
temp = set(temp)
if not is_cycle and \
any(i not in temp for i in range(len(temp))):
raise ValueError("Integers 0 through %s must be present." %
max(temp))
if is_cycle:
# it's not necessarily canonical so we won't store
# it -- use the array form instead
c = Cycle()
for ci in args:
c = c(*ci)
aform = c.list()
else:
aform = list(args)
if size and size > len(aform):
# don't allow for truncation of permutation which
# might split a cycle and lead to an invalid aform
# but do allow the permutation size to be increased
aform.extend(list(range(len(aform), size)))
return cls._af_new(aform)
@classmethod
def _af_new(cls, perm):
"""A method to produce a Permutation object from a list;
the list is bound to the _array_form attribute, so it must
not be modified; this method is meant for internal use only;
the list ``a`` is supposed to be generated as a temporary value
in a method, so p = Perm._af_new(a) is the only object
to hold a reference to ``a``::
Examples
========
>>> from sympy.combinatorics.permutations import Perm
>>> Perm.print_cyclic = False
>>> a = [2,1,3,0]
>>> p = Perm._af_new(a)
>>> p
Permutation([2, 1, 3, 0])
"""
p = Basic.__new__(cls, perm)
p._array_form = perm
p._size = len(perm)
return p
def _hashable_content(self):
# the array_form (a list) is the Permutation arg, so we need to
# return a tuple, instead
return tuple(self.array_form)
@property
def array_form(self):
"""
Return a copy of the attribute _array_form
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([[2, 0], [3, 1]])
>>> p.array_form
[2, 3, 0, 1]
>>> Permutation([[2, 0, 3, 1]]).array_form
[3, 2, 0, 1]
>>> Permutation([2, 0, 3, 1]).array_form
[2, 0, 3, 1]
>>> Permutation([[1, 2], [4, 5]]).array_form
[0, 2, 1, 3, 5, 4]
"""
return self._array_form[:]
def __repr__(self):
from sympy.combinatorics.permutations import Permutation, Cycle
if Permutation.print_cyclic:
if not self.size:
return 'Permutation()'
# before taking Cycle notation, see if the last element is
# a singleton and move it to the head of the string
s = Cycle(self)(self.size - 1).__repr__()[len('Cycle'):]
last = s.rfind('(')
if not last == 0 and ',' not in s[last:]:
s = s[last:] + s[:last]
return 'Permutation%s' %s
else:
s = self.support()
if not s:
if self.size < 5:
return 'Permutation(%s)' % str(self.array_form)
return 'Permutation([], size=%s)' % self.size
trim = str(self.array_form[:s[-1] + 1]) + ', size=%s' % self.size
use = full = str(self.array_form)
if len(trim) < len(full):
use = trim
return 'Permutation(%s)' % use
def list(self, size=None):
"""Return the permutation as an explicit list, possibly
trimming unmoved elements if size is less than the maximum
element in the permutation; if this is desired, setting
``size=-1`` will guarantee such trimming.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation(2, 3)(4, 5)
>>> p.list()
[0, 1, 3, 2, 5, 4]
>>> p.list(10)
[0, 1, 3, 2, 5, 4, 6, 7, 8, 9]
Passing a length too small will trim trailing, unchanged elements
in the permutation:
>>> Permutation(2, 4)(1, 2, 4).list(-1)
[0, 2, 1]
>>> Permutation(3).list(-1)
[]
"""
if not self and size is None:
raise ValueError('must give size for empty Cycle')
rv = self.array_form
if size is not None:
if size > self.size:
rv.extend(list(range(self.size, size)))
else:
# find first value from rhs where rv[i] != i
i = self.size - 1
while rv:
if rv[-1] != i:
break
rv.pop()
i -= 1
return rv
@property
def cyclic_form(self):
"""
This is used to convert to the cyclic notation
from the canonical notation. Singletons are omitted.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([0, 3, 1, 2])
>>> p.cyclic_form
[[1, 3, 2]]
>>> Permutation([1, 0, 2, 4, 3, 5]).cyclic_form
[[0, 1], [3, 4]]
See Also
========
array_form, full_cyclic_form
"""
if self._cyclic_form is not None:
return list(self._cyclic_form)
array_form = self.array_form
unchecked = [True] * len(array_form)
cyclic_form = []
for i in range(len(array_form)):
if unchecked[i]:
cycle = []
cycle.append(i)
unchecked[i] = False
j = i
while unchecked[array_form[j]]:
j = array_form[j]
cycle.append(j)
unchecked[j] = False
if len(cycle) > 1:
cyclic_form.append(cycle)
assert cycle == list(minlex(cycle, is_set=True))
cyclic_form.sort()
self._cyclic_form = cyclic_form[:]
return cyclic_form
@property
def full_cyclic_form(self):
"""Return permutation in cyclic form including singletons.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation([0, 2, 1]).full_cyclic_form
[[0], [1, 2]]
"""
need = set(range(self.size)) - set(flatten(self.cyclic_form))
rv = self.cyclic_form
rv.extend([[i] for i in need])
rv.sort()
return rv
@property
def size(self):
"""
Returns the number of elements in the permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([[3, 2], [0, 1]]).size
4
See Also
========
cardinality, length, order, rank
"""
return self._size
def support(self):
"""Return the elements in permutation, P, for which P[i] != i.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation([[3, 2], [0, 1], [4]])
>>> p.array_form
[1, 0, 3, 2, 4]
>>> p.support()
[0, 1, 2, 3]
"""
a = self.array_form
return [i for i, e in enumerate(a) if a[i] != i]
def __add__(self, other):
"""Return permutation that is other higher in rank than self.
The rank is the lexicographical rank, with the identity permutation
having rank of 0.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> I = Permutation([0, 1, 2, 3])
>>> a = Permutation([2, 1, 3, 0])
>>> I + a.rank() == a
True
See Also
========
__sub__, inversion_vector
"""
rank = (self.rank() + other) % self.cardinality
rv = self.unrank_lex(self.size, rank)
rv._rank = rank
return rv
def __sub__(self, other):
"""Return the permutation that is other lower in rank than self.
See Also
========
__add__
"""
return self.__add__(-other)
@staticmethod
def rmul(*args):
"""
Return product of Permutations [a, b, c, ...] as the Permutation whose
ith value is a(b(c(i))).
a, b, c, ... can be Permutation objects or tuples.
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> Permutation.print_cyclic = False
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> a = Permutation(a); b = Permutation(b)
>>> list(Permutation.rmul(a, b))
[1, 2, 0]
>>> [a(b(i)) for i in range(3)]
[1, 2, 0]
This handles the operands in reverse order compared to the ``*`` operator:
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
Notes
=====
All items in the sequence will be parsed by Permutation as
necessary as long as the first item is a Permutation:
>>> Permutation.rmul(a, [0, 2, 1]) == Permutation.rmul(a, b)
True
The reverse order of arguments will raise a TypeError.
"""
rv = args[0]
for i in range(1, len(args)):
rv = args[i]*rv
return rv
@classmethod
def rmul_with_af(cls, *args):
"""
same as rmul, but the elements of args are Permutation objects
which have _array_form
"""
a = [x._array_form for x in args]
rv = cls._af_new(_af_rmuln(*a))
return rv
def mul_inv(self, other):
"""
other*~self, self and other have _array_form
"""
a = _af_invert(self._array_form)
b = other._array_form
return self._af_new(_af_rmul(a, b))
def __rmul__(self, other):
"""This is needed to coerce other to Permutation in rmul."""
cls = type(self)
return cls(other)*self
def __mul__(self, other):
"""
Return the product a*b as a Permutation; the ith value is b(a(i)).
Examples
========
>>> from sympy.combinatorics.permutations import _af_rmul, Permutation
>>> Permutation.print_cyclic = False
>>> a, b = [1, 0, 2], [0, 2, 1]
>>> a = Permutation(a); b = Permutation(b)
>>> list(a*b)
[2, 0, 1]
>>> [b(a(i)) for i in range(3)]
[2, 0, 1]
This handles operands in reverse order compared to _af_rmul and rmul:
>>> al = list(a); bl = list(b)
>>> _af_rmul(al, bl)
[1, 2, 0]
>>> [al[bl[i]] for i in range(3)]
[1, 2, 0]
It is acceptable for the arrays to have different lengths; the shorter
one will be padded to match the longer one:
>>> b*Permutation([1, 0])
Permutation([1, 2, 0])
>>> Permutation([1, 0])*b
Permutation([2, 0, 1])
It is also acceptable to allow coercion to handle conversion of a
single list to the left of a Permutation:
>>> [0, 1]*a # no change: 2-element identity
Permutation([1, 0, 2])
>>> [[0, 1]]*a # exchange first two elements
Permutation([0, 1, 2])
You cannot use more than 1 cycle notation in a product of cycles
since coercion can only handle one argument to the left. To handle
multiple cycles it is convenient to use Cycle instead of Permutation:
>>> [[1, 2]]*[[2, 3]]*Permutation([]) # doctest: +SKIP
>>> from sympy.combinatorics.permutations import Cycle
>>> Cycle(1, 2)(2, 3)
(1 3 2)
"""
a = self.array_form
# __rmul__ makes sure the other is a Permutation
b = other.array_form
if not b:
perm = a
else:
b.extend(list(range(len(b), len(a))))
perm = [b[i] for i in a] + b[len(a):]
return self._af_new(perm)
def commutes_with(self, other):
"""
Checks if the elements are commuting.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> a = Permutation([1, 4, 3, 0, 2, 5])
>>> b = Permutation([0, 1, 2, 3, 4, 5])
>>> a.commutes_with(b)
True
>>> b = Permutation([2, 3, 5, 4, 1, 0])
>>> a.commutes_with(b)
False
"""
a = self.array_form
b = other.array_form
return _af_commutes_with(a, b)
def __pow__(self, n):
"""
Routine for finding powers of a permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([2,0,3,1])
>>> p.order()
4
>>> p**4
Permutation([0, 1, 2, 3])
"""
if isinstance(n, Permutation):
raise NotImplementedError(
'p**p is not defined; do you mean p^p (conjugate)?')
n = int(n)
return self._af_new(_af_pow(self.array_form, n))
def __rxor__(self, i):
"""Return self(i) when ``i`` is an int.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> p = Permutation(1, 2, 9)
>>> 2^p == p(2) == 9
True
"""
if int(i) == i:
return self(i)
else:
raise NotImplementedError(
"i^p = p(i) when i is an integer, not %s." % i)
def __xor__(self, h):
"""Return the conjugate permutation ``~h*self*h` `.
If ``a`` and ``b`` are conjugates, ``a = h*b*~h`` and
``b = ~h*a*h`` and both have the same cycle structure.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = True
>>> p = Permutation(1, 2, 9)
>>> q = Permutation(6, 9, 8)
>>> p*q != q*p
True
Calculate and check properties of the conjugate:
>>> c = p^q
>>> c == ~q*p*q and p == q*c*~q
True
The expression q^p^r is equivalent to q^(p*r):
>>> r = Permutation(9)(4, 6, 8)
>>> q^p^r == q^(p*r)
True
If the term to the left of the conjugate operator, i, is an integer
then this is interpreted as selecting the ith element from the
permutation to the right:
>>> all(i^p == p(i) for i in range(p.size))
True
Note that the * operator as higher precedence than the ^ operator:
>>> q^r*p^r == q^(r*p)^r == Permutation(9)(1, 6, 4)
True
Notes
=====
In Python the precedence rule is p^q^r = (p^q)^r which differs
in general from p^(q^r)
>>> q^p^r
(9)(1 4 8)
>>> q^(p^r)
(9)(1 8 6)
For a given r and p, both of the following are conjugates of p:
~r*p*r and r*p*~r. But these are not necessarily the same:
>>> ~r*p*r == r*p*~r
True
>>> p = Permutation(1, 2, 9)(5, 6)
>>> ~r*p*r == r*p*~r
False
The conjugate ~r*p*r was chosen so that ``p^q^r`` would be equivalent
to ``p^(q*r)`` rather than ``p^(r*q)``. To obtain r*p*~r, pass ~r to
this method:
>>> p^~r == r*p*~r
True
"""
if self.size != h.size:
raise ValueError("The permutations must be of equal size.")
a = [None]*self.size
h = h._array_form
p = self._array_form
for i in range(self.size):
a[h[i]] = h[p[i]]
return self._af_new(a)
def transpositions(self):
"""
Return the permutation decomposed into a list of transpositions.
It is always possible to express a permutation as the product of
transpositions, see [1]
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([[1, 2, 3], [0, 4, 5, 6, 7]])
>>> t = p.transpositions()
>>> t
[(0, 7), (0, 6), (0, 5), (0, 4), (1, 3), (1, 2)]
>>> print(''.join(str(c) for c in t))
(0, 7)(0, 6)(0, 5)(0, 4)(1, 3)(1, 2)
>>> Permutation.rmul(*[Permutation([ti], size=p.size) for ti in t]) == p
True
References
==========
1. https://en.wikipedia.org/wiki/Transposition_%28mathematics%29#Properties
"""
a = self.cyclic_form
res = []
for x in a:
nx = len(x)
if nx == 2:
res.append(tuple(x))
elif nx > 2:
first = x[0]
for y in x[nx - 1:0:-1]:
res.append((first, y))
return res
@classmethod
def from_sequence(self, i, key=None):
"""Return the permutation needed to obtain ``i`` from the sorted
elements of ``i``. If custom sorting is desired, a key can be given.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.print_cyclic = True
>>> Permutation.from_sequence('SymPy')
(4)(0 1 3)
>>> _(sorted("SymPy"))
['S', 'y', 'm', 'P', 'y']
>>> Permutation.from_sequence('SymPy', key=lambda x: x.lower())
(4)(0 2)(1 3)
"""
ic = list(zip(i, list(range(len(i)))))
if key:
ic.sort(key=lambda x: key(x[0]))
else:
ic.sort()
return ~Permutation([i[1] for i in ic])
def __invert__(self):
"""
Return the inverse of the permutation.
A permutation multiplied by its inverse is the identity permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([[2,0], [3,1]])
>>> ~p
Permutation([2, 3, 0, 1])
>>> _ == p**-1
True
>>> p*~p == ~p*p == Permutation([0, 1, 2, 3])
True
"""
return self._af_new(_af_invert(self._array_form))
def __iter__(self):
"""Yield elements from array form.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> list(Permutation(range(3)))
[0, 1, 2]
"""
for i in self.array_form:
yield i
def __call__(self, *i):
"""
Allows applying a permutation instance as a bijective function.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([[2, 0], [3, 1]])
>>> p.array_form
[2, 3, 0, 1]
>>> [p(i) for i in range(4)]
[2, 3, 0, 1]
If an array is given then the permutation selects the items
from the array (i.e. the permutation is applied to the array):
>>> from sympy.abc import x
>>> p([x, 1, 0, x**2])
[0, x**2, x, 1]
"""
# list indices can be Integer or int; leave this
# as it is (don't test or convert it) because this
# gets called a lot and should be fast
if len(i) == 1:
i = i[0]
try:
# P(1)
return self._array_form[i]
except TypeError:
try:
# P([a, b, c])
return [i[j] for j in self._array_form]
except Exception:
raise TypeError('unrecognized argument')
else:
# P(1, 2, 3)
return self*Permutation(Cycle(*i), size=self.size)
def atoms(self):
"""
Returns all the elements of a permutation
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 1, 2, 3, 4, 5]).atoms()
{0, 1, 2, 3, 4, 5}
>>> Permutation([[0, 1], [2, 3], [4, 5]]).atoms()
{0, 1, 2, 3, 4, 5}
"""
return set(self.array_form)
def next_lex(self):
"""
Returns the next permutation in lexicographical order.
If self is the last permutation in lexicographical order
it returns None.
See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([2, 3, 1, 0])
>>> p = Permutation([2, 3, 1, 0]); p.rank()
17
>>> p = p.next_lex(); p.rank()
18
See Also
========
rank, unrank_lex
"""
perm = self.array_form[:]
n = len(perm)
i = n - 2
while perm[i + 1] < perm[i]:
i -= 1
if i == -1:
return None
else:
j = n - 1
while perm[j] < perm[i]:
j -= 1
perm[j], perm[i] = perm[i], perm[j]
i += 1
j = n - 1
while i < j:
perm[j], perm[i] = perm[i], perm[j]
i += 1
j -= 1
return self._af_new(perm)
@classmethod
def unrank_nonlex(self, n, r):
"""
This is a linear time unranking algorithm that does not
respect lexicographic order [3].
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> Permutation.unrank_nonlex(4, 5)
Permutation([2, 0, 3, 1])
>>> Permutation.unrank_nonlex(4, -1)
Permutation([0, 1, 2, 3])
See Also
========
next_nonlex, rank_nonlex
"""
def _unrank1(n, r, a):
if n > 0:
a[n - 1], a[r % n] = a[r % n], a[n - 1]
_unrank1(n - 1, r//n, a)
id_perm = list(range(n))
n = int(n)
r = r % ifac(n)
_unrank1(n, r, id_perm)
return self._af_new(id_perm)
def rank_nonlex(self, inv_perm=None):
"""
This is a linear time ranking algorithm that does not
enforce lexicographic order [3].
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank_nonlex()
23
See Also
========
next_nonlex, unrank_nonlex
"""
def _rank1(n, perm, inv_perm):
if n == 1:
return 0
s = perm[n - 1]
t = inv_perm[n - 1]
perm[n - 1], perm[t] = perm[t], s
inv_perm[n - 1], inv_perm[s] = inv_perm[s], t
return s + n*_rank1(n - 1, perm, inv_perm)
if inv_perm is None:
inv_perm = (~self).array_form
if not inv_perm:
return 0
perm = self.array_form[:]
r = _rank1(len(perm), perm, inv_perm)
return r
def next_nonlex(self):
"""
Returns the next permutation in nonlex order [3].
If self is the last permutation in this order it returns None.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([2, 0, 3, 1]); p.rank_nonlex()
5
>>> p = p.next_nonlex(); p
Permutation([3, 0, 1, 2])
>>> p.rank_nonlex()
6
See Also
========
rank_nonlex, unrank_nonlex
"""
r = self.rank_nonlex()
if r == ifac(self.size) - 1:
return None
return self.unrank_nonlex(self.size, r + 1)
def rank(self):
"""
Returns the lexicographic rank of the permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank()
0
>>> p = Permutation([3, 2, 1, 0])
>>> p.rank()
23
See Also
========
next_lex, unrank_lex, cardinality, length, order, size
"""
if not self._rank is None:
return self._rank
rank = 0
rho = self.array_form[:]
n = self.size - 1
size = n + 1
psize = int(ifac(n))
for j in range(size - 1):
rank += rho[j]*psize
for i in range(j + 1, size):
if rho[i] > rho[j]:
rho[i] -= 1
psize //= n
n -= 1
self._rank = rank
return rank
@property
def cardinality(self):
"""
Returns the number of all possible permutations.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.cardinality
24
See Also
========
length, order, rank, size
"""
return int(ifac(self.size))
def parity(self):
"""
Computes the parity of a permutation.
The parity of a permutation reflects the parity of the
number of inversions in the permutation, i.e., the
number of pairs of x and y such that ``x > y`` but ``p[x] < p[y]``.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.parity()
0
>>> p = Permutation([3, 2, 0, 1])
>>> p.parity()
1
See Also
========
_af_parity
"""
if self._cyclic_form is not None:
return (self.size - self.cycles) % 2
return _af_parity(self.array_form)
@property
def is_even(self):
"""
Checks if a permutation is even.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.is_even
True
>>> p = Permutation([3, 2, 1, 0])
>>> p.is_even
True
See Also
========
is_odd
"""
return not self.is_odd
@property
def is_odd(self):
"""
Checks if a permutation is odd.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.is_odd
False
>>> p = Permutation([3, 2, 0, 1])
>>> p.is_odd
True
See Also
========
is_even
"""
return bool(self.parity() % 2)
@property
def is_Singleton(self):
"""
Checks to see if the permutation contains only one number and is
thus the only possible permutation of this set of numbers
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0]).is_Singleton
True
>>> Permutation([0, 1]).is_Singleton
False
See Also
========
is_Empty
"""
return self.size == 1
@property
def is_Empty(self):
"""
Checks to see if the permutation is a set with zero elements
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([]).is_Empty
True
>>> Permutation([0]).is_Empty
False
See Also
========
is_Singleton
"""
return self.size == 0
@property
def is_identity(self):
return self.is_Identity
@property
def is_Identity(self):
"""
Returns True if the Permutation is an identity permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([])
>>> p.is_Identity
True
>>> p = Permutation([[0], [1], [2]])
>>> p.is_Identity
True
>>> p = Permutation([0, 1, 2])
>>> p.is_Identity
True
>>> p = Permutation([0, 2, 1])
>>> p.is_Identity
False
See Also
========
order
"""
af = self.array_form
return not af or all(i == af[i] for i in range(self.size))
def ascents(self):
"""
Returns the positions of ascents in a permutation, ie, the location
where p[i] < p[i+1]
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([4, 0, 1, 3, 2])
>>> p.ascents()
[1, 2]
See Also
========
descents, inversions, min, max
"""
a = self.array_form
pos = [i for i in range(len(a) - 1) if a[i] < a[i + 1]]
return pos
def descents(self):
"""
Returns the positions of descents in a permutation, ie, the location
where p[i] > p[i+1]
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([4, 0, 1, 3, 2])
>>> p.descents()
[0, 3]
See Also
========
ascents, inversions, min, max
"""
a = self.array_form
pos = [i for i in range(len(a) - 1) if a[i] > a[i + 1]]
return pos
def max(self):
"""
The maximum element moved by the permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([1, 0, 2, 3, 4])
>>> p.max()
1
See Also
========
min, descents, ascents, inversions
"""
max = 0
a = self.array_form
for i in range(len(a)):
if a[i] != i and a[i] > max:
max = a[i]
return max
def min(self):
"""
The minimum element moved by the permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 4, 3, 2])
>>> p.min()
2
See Also
========
max, descents, ascents, inversions
"""
a = self.array_form
min = len(a)
for i in range(len(a)):
if a[i] != i and a[i] < min:
min = a[i]
return min
def inversions(self):
"""
Computes the number of inversions of a permutation.
An inversion is where i > j but p[i] < p[j].
For small length of p, it iterates over all i and j
values and calculates the number of inversions.
For large length of p, it uses a variation of merge
sort to calculate the number of inversions.
References
==========
[1] http://www.cp.eng.chula.ac.th/~piak/teaching/algo/algo2008/count-inv.htm
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3, 4, 5])
>>> p.inversions()
0
>>> Permutation([3, 2, 1, 0]).inversions()
6
See Also
========
descents, ascents, min, max
"""
inversions = 0
a = self.array_form
n = len(a)
if n < 130:
for i in range(n - 1):
b = a[i]
for c in a[i + 1:]:
if b > c:
inversions += 1
else:
k = 1
right = 0
arr = a[:]
temp = a[:]
while k < n:
i = 0
while i + k < n:
right = i + k * 2 - 1
if right >= n:
right = n - 1
inversions += _merge(arr, temp, i, i + k, right)
i = i + k * 2
k = k * 2
return inversions
def commutator(self, x):
"""Return the commutator of self and x: ``~x*~self*x*self``
If f and g are part of a group, G, then the commutator of f and g
is the group identity iff f and g commute, i.e. fg == gf.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([0, 2, 3, 1])
>>> x = Permutation([2, 0, 3, 1])
>>> c = p.commutator(x); c
Permutation([2, 1, 3, 0])
>>> c == ~x*~p*x*p
True
>>> I = Permutation(3)
>>> p = [I + i for i in range(6)]
>>> for i in range(len(p)):
... for j in range(len(p)):
... c = p[i].commutator(p[j])
... if p[i]*p[j] == p[j]*p[i]:
... assert c == I
... else:
... assert c != I
...
References
==========
https://en.wikipedia.org/wiki/Commutator
"""
a = self.array_form
b = x.array_form
n = len(a)
if len(b) != n:
raise ValueError("The permutations must be of equal size.")
inva = [None]*n
for i in range(n):
inva[a[i]] = i
invb = [None]*n
for i in range(n):
invb[b[i]] = i
return self._af_new([a[b[inva[i]]] for i in invb])
def signature(self):
"""
Gives the signature of the permutation needed to place the
elements of the permutation in canonical order.
The signature is calculated as (-1)^<number of inversions>
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2])
>>> p.inversions()
0
>>> p.signature()
1
>>> q = Permutation([0,2,1])
>>> q.inversions()
1
>>> q.signature()
-1
See Also
========
inversions
"""
if self.is_even:
return 1
return -1
def order(self):
"""
Computes the order of a permutation.
When the permutation is raised to the power of its
order it equals the identity permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([3, 1, 5, 2, 4, 0])
>>> p.order()
4
>>> (p**(p.order()))
Permutation([], size=6)
See Also
========
identity, cardinality, length, rank, size
"""
return reduce(lcm, [len(cycle) for cycle in self.cyclic_form], 1)
def length(self):
"""
Returns the number of integers moved by a permutation.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 3, 2, 1]).length()
2
>>> Permutation([[0, 1], [2, 3]]).length()
4
See Also
========
min, max, support, cardinality, order, rank, size
"""
return len(self.support())
@property
def cycle_structure(self):
"""Return the cycle structure of the permutation as a dictionary
indicating the multiplicity of each cycle length.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.print_cyclic = True
>>> Permutation(3).cycle_structure
{1: 4}
>>> Permutation(0, 4, 3)(1, 2)(5, 6).cycle_structure
{2: 2, 3: 1}
"""
if self._cycle_structure:
rv = self._cycle_structure
else:
rv = defaultdict(int)
singletons = self.size
for c in self.cyclic_form:
rv[len(c)] += 1
singletons -= len(c)
if singletons:
rv[1] = singletons
self._cycle_structure = rv
return dict(rv) # make a copy
@property
def cycles(self):
"""
Returns the number of cycles contained in the permutation
(including singletons).
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation([0, 1, 2]).cycles
3
>>> Permutation([0, 1, 2]).full_cyclic_form
[[0], [1], [2]]
>>> Permutation(0, 1)(2, 3).cycles
2
See Also
========
sympy.functions.combinatorial.numbers.stirling
"""
return len(self.full_cyclic_form)
def index(self):
"""
Returns the index of a permutation.
The index of a permutation is the sum of all subscripts j such
that p[j] is greater than p[j+1].
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([3, 0, 2, 1, 4])
>>> p.index()
2
"""
a = self.array_form
return sum([j for j in range(len(a) - 1) if a[j] > a[j + 1]])
def runs(self):
"""
Returns the runs of a permutation.
An ascending sequence in a permutation is called a run [5].
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([2, 5, 7, 3, 6, 0, 1, 4, 8])
>>> p.runs()
[[2, 5, 7], [3, 6], [0, 1, 4, 8]]
>>> q = Permutation([1,3,2,0])
>>> q.runs()
[[1, 3], [2], [0]]
"""
return runs(self.array_form)
def inversion_vector(self):
"""Return the inversion vector of the permutation.
The inversion vector consists of elements whose value
indicates the number of elements in the permutation
that are lesser than it and lie on its right hand side.
The inversion vector is the same as the Lehmer encoding of a
permutation.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([4, 8, 0, 7, 1, 5, 3, 6, 2])
>>> p.inversion_vector()
[4, 7, 0, 5, 0, 2, 1, 1]
>>> p = Permutation([3, 2, 1, 0])
>>> p.inversion_vector()
[3, 2, 1]
The inversion vector increases lexicographically with the rank
of the permutation, the -ith element cycling through 0..i.
>>> p = Permutation(2)
>>> while p:
... print('%s %s %s' % (p, p.inversion_vector(), p.rank()))
... p = p.next_lex()
...
Permutation([0, 1, 2]) [0, 0] 0
Permutation([0, 2, 1]) [0, 1] 1
Permutation([1, 0, 2]) [1, 0] 2
Permutation([1, 2, 0]) [1, 1] 3
Permutation([2, 0, 1]) [2, 0] 4
Permutation([2, 1, 0]) [2, 1] 5
See Also
========
from_inversion_vector
"""
self_array_form = self.array_form
n = len(self_array_form)
inversion_vector = [0] * (n - 1)
for i in range(n - 1):
val = 0
for j in range(i + 1, n):
if self_array_form[j] < self_array_form[i]:
val += 1
inversion_vector[i] = val
return inversion_vector
def rank_trotterjohnson(self):
"""
Returns the Trotter Johnson rank, which we get from the minimal
change algorithm. See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 1, 2, 3])
>>> p.rank_trotterjohnson()
0
>>> p = Permutation([0, 2, 1, 3])
>>> p.rank_trotterjohnson()
7
See Also
========
unrank_trotterjohnson, next_trotterjohnson
"""
if self.array_form == [] or self.is_Identity:
return 0
if self.array_form == [1, 0]:
return 1
perm = self.array_form
n = self.size
rank = 0
for j in range(1, n):
k = 1
i = 0
while perm[i] != j:
if perm[i] < j:
k += 1
i += 1
j1 = j + 1
if rank % 2 == 0:
rank = j1*rank + j1 - k
else:
rank = j1*rank + k - 1
return rank
@classmethod
def unrank_trotterjohnson(cls, size, rank):
"""
Trotter Johnson permutation unranking. See [4] section 2.4.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.unrank_trotterjohnson(5, 10)
Permutation([0, 3, 1, 2, 4])
See Also
========
rank_trotterjohnson, next_trotterjohnson
"""
perm = [0]*size
r2 = 0
n = ifac(size)
pj = 1
for j in range(2, size + 1):
pj *= j
r1 = (rank * pj) // n
k = r1 - j*r2
if r2 % 2 == 0:
for i in range(j - 1, j - k - 1, -1):
perm[i] = perm[i - 1]
perm[j - k - 1] = j - 1
else:
for i in range(j - 1, k, -1):
perm[i] = perm[i - 1]
perm[k] = j - 1
r2 = r1
return cls._af_new(perm)
def next_trotterjohnson(self):
"""
Returns the next permutation in Trotter-Johnson order.
If self is the last permutation it returns None.
See [4] section 2.4. If it is desired to generate all such
permutations, they can be generated in order more quickly
with the ``generate_bell`` function.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation([3, 0, 2, 1])
>>> p.rank_trotterjohnson()
4
>>> p = p.next_trotterjohnson(); p
Permutation([0, 3, 2, 1])
>>> p.rank_trotterjohnson()
5
See Also
========
rank_trotterjohnson, unrank_trotterjohnson, sympy.utilities.iterables.generate_bell
"""
pi = self.array_form[:]
n = len(pi)
st = 0
rho = pi[:]
done = False
m = n-1
while m > 0 and not done:
d = rho.index(m)
for i in range(d, m):
rho[i] = rho[i + 1]
par = _af_parity(rho[:m])
if par == 1:
if d == m:
m -= 1
else:
pi[st + d], pi[st + d + 1] = pi[st + d + 1], pi[st + d]
done = True
else:
if d == 0:
m -= 1
st += 1
else:
pi[st + d], pi[st + d - 1] = pi[st + d - 1], pi[st + d]
done = True
if m == 0:
return None
return self._af_new(pi)
def get_precedence_matrix(self):
"""
Gets the precedence matrix. This is used for computing the
distance between two permutations.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> p = Permutation.josephus(3, 6, 1)
>>> p
Permutation([2, 5, 3, 1, 4, 0])
>>> p.get_precedence_matrix()
Matrix([
[0, 0, 0, 0, 0, 0],
[1, 0, 0, 0, 1, 0],
[1, 1, 0, 1, 1, 1],
[1, 1, 0, 0, 1, 0],
[1, 0, 0, 0, 0, 0],
[1, 1, 0, 1, 1, 0]])
See Also
========
get_precedence_distance, get_adjacency_matrix, get_adjacency_distance
"""
m = zeros(self.size)
perm = self.array_form
for i in range(m.rows):
for j in range(i + 1, m.cols):
m[perm[i], perm[j]] = 1
return m
def get_precedence_distance(self, other):
"""
Computes the precedence distance between two permutations.
Suppose p and p' represent n jobs. The precedence metric
counts the number of times a job j is preceded by job i
in both p and p'. This metric is commutative.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([2, 0, 4, 3, 1])
>>> q = Permutation([3, 1, 2, 4, 0])
>>> p.get_precedence_distance(q)
7
>>> q.get_precedence_distance(p)
7
See Also
========
get_precedence_matrix, get_adjacency_matrix, get_adjacency_distance
"""
if self.size != other.size:
raise ValueError("The permutations must be of equal size.")
self_prec_mat = self.get_precedence_matrix()
other_prec_mat = other.get_precedence_matrix()
n_prec = 0
for i in range(self.size):
for j in range(self.size):
if i == j:
continue
if self_prec_mat[i, j] * other_prec_mat[i, j] == 1:
n_prec += 1
d = self.size * (self.size - 1)//2 - n_prec
return d
def get_adjacency_matrix(self):
"""
Computes the adjacency matrix of a permutation.
If job i is adjacent to job j in a permutation p
then we set m[i, j] = 1 where m is the adjacency
matrix of p.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation.josephus(3, 6, 1)
>>> p.get_adjacency_matrix()
Matrix([
[0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 1, 0],
[0, 0, 0, 0, 0, 1],
[0, 1, 0, 0, 0, 0],
[1, 0, 0, 0, 0, 0],
[0, 0, 0, 1, 0, 0]])
>>> q = Permutation([0, 1, 2, 3])
>>> q.get_adjacency_matrix()
Matrix([
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1],
[0, 0, 0, 0]])
See Also
========
get_precedence_matrix, get_precedence_distance, get_adjacency_distance
"""
m = zeros(self.size)
perm = self.array_form
for i in range(self.size - 1):
m[perm[i], perm[i + 1]] = 1
return m
def get_adjacency_distance(self, other):
"""
Computes the adjacency distance between two permutations.
This metric counts the number of times a pair i,j of jobs is
adjacent in both p and p'. If n_adj is this quantity then
the adjacency distance is n - n_adj - 1 [1]
[1] Reeves, Colin R. Landscapes, Operators and Heuristic search, Annals
of Operational Research, 86, pp 473-490. (1999)
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 3, 1, 2, 4])
>>> q = Permutation.josephus(4, 5, 2)
>>> p.get_adjacency_distance(q)
3
>>> r = Permutation([0, 2, 1, 4, 3])
>>> p.get_adjacency_distance(r)
4
See Also
========
get_precedence_matrix, get_precedence_distance, get_adjacency_matrix
"""
if self.size != other.size:
raise ValueError("The permutations must be of the same size.")
self_adj_mat = self.get_adjacency_matrix()
other_adj_mat = other.get_adjacency_matrix()
n_adj = 0
for i in range(self.size):
for j in range(self.size):
if i == j:
continue
if self_adj_mat[i, j] * other_adj_mat[i, j] == 1:
n_adj += 1
d = self.size - n_adj - 1
return d
def get_positional_distance(self, other):
"""
Computes the positional distance between two permutations.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> p = Permutation([0, 3, 1, 2, 4])
>>> q = Permutation.josephus(4, 5, 2)
>>> r = Permutation([3, 1, 4, 0, 2])
>>> p.get_positional_distance(q)
12
>>> p.get_positional_distance(r)
12
See Also
========
get_precedence_distance, get_adjacency_distance
"""
a = self.array_form
b = other.array_form
if len(a) != len(b):
raise ValueError("The permutations must be of the same size.")
return sum([abs(a[i] - b[i]) for i in range(len(a))])
@classmethod
def josephus(cls, m, n, s=1):
"""Return as a permutation the shuffling of range(n) using the Josephus
scheme in which every m-th item is selected until all have been chosen.
The returned permutation has elements listed by the order in which they
were selected.
The parameter ``s`` stops the selection process when there are ``s``
items remaining and these are selected by continuing the selection,
counting by 1 rather than by ``m``.
Consider selecting every 3rd item from 6 until only 2 remain::
choices chosen
======== ======
012345
01 345 2
01 34 25
01 4 253
0 4 2531
0 25314
253140
Examples
========
>>> from sympy.combinatorics import Permutation
>>> Permutation.josephus(3, 6, 2).array_form
[2, 5, 3, 1, 4, 0]
References
==========
1. https://en.wikipedia.org/wiki/Flavius_Josephus
2. https://en.wikipedia.org/wiki/Josephus_problem
3. http://www.wou.edu/~burtonl/josephus.html
"""
from collections import deque
m -= 1
Q = deque(list(range(n)))
perm = []
while len(Q) > max(s, 1):
for dp in range(m):
Q.append(Q.popleft())
perm.append(Q.popleft())
perm.extend(list(Q))
return cls(perm)
@classmethod
def from_inversion_vector(cls, inversion):
"""
Calculates the permutation from the inversion vector.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> Permutation.from_inversion_vector([3, 2, 1, 0, 0])
Permutation([3, 2, 1, 0, 4, 5])
"""
size = len(inversion)
N = list(range(size + 1))
perm = []
try:
for k in range(size):
val = N[inversion[k]]
perm.append(val)
N.remove(val)
except IndexError:
raise ValueError("The inversion vector is not valid.")
perm.extend(N)
return cls._af_new(perm)
@classmethod
def random(cls, n):
"""
Generates a random permutation of length ``n``.
Uses the underlying Python pseudo-random number generator.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.random(2) in (Permutation([1, 0]), Permutation([0, 1]))
True
"""
perm_array = list(range(n))
random.shuffle(perm_array)
return cls._af_new(perm_array)
@classmethod
def unrank_lex(cls, size, rank):
"""
Lexicographic permutation unranking.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> Permutation.print_cyclic = False
>>> a = Permutation.unrank_lex(5, 10)
>>> a.rank()
10
>>> a
Permutation([0, 2, 4, 1, 3])
See Also
========
rank, next_lex
"""
perm_array = [0] * size
psize = 1
for i in range(size):
new_psize = psize*(i + 1)
d = (rank % new_psize) // psize
rank -= d*psize
perm_array[size - i - 1] = d
for j in range(size - i, size):
if perm_array[j] > d - 1:
perm_array[j] += 1
psize = new_psize
return cls._af_new(perm_array)
# global flag to control how permutations are printed
# when True, Permutation([0, 2, 1, 3]) -> Cycle(1, 2)
# when False, Permutation([0, 2, 1, 3]) -> Permutation([0, 2, 1])
print_cyclic = True
def _merge(arr, temp, left, mid, right):
"""
Merges two sorted arrays and calculates the inversion count.
Helper function for calculating inversions. This method is
for internal use only.
"""
i = k = left
j = mid
inv_count = 0
while i < mid and j <= right:
if arr[i] < arr[j]:
temp[k] = arr[i]
k += 1
i += 1
else:
temp[k] = arr[j]
k += 1
j += 1
inv_count += (mid -i)
while i < mid:
temp[k] = arr[i]
k += 1
i += 1
if j <= right:
k += right - j + 1
j += right - j + 1
arr[left:k + 1] = temp[left:k + 1]
else:
arr[left:right + 1] = temp[left:right + 1]
return inv_count
Perm = Permutation
_af_new = Perm._af_new
|
62d09760a7c82b30765e7d41fad7636d8d339926ba0c61c98d85eb21c1f5888e
|
from __future__ import print_function, division
from sympy.core.compatibility import range
from sympy.combinatorics.permutations import Permutation, _af_rmul, \
_af_invert, _af_new
from sympy.combinatorics.perm_groups import PermutationGroup, _orbit, \
_orbit_transversal
from sympy.combinatorics.util import _distribute_gens_by_base, \
_orbits_transversals_from_bsgs
"""
References for tensor canonicalization:
[1] R. Portugal "Algorithmic simplification of tensor expressions",
J. Phys. A 32 (1999) 7779-7789
[2] R. Portugal, B.F. Svaiter "Group-theoretic Approach for Symbolic
Tensor Manipulation: I. Free Indices"
arXiv:math-ph/0107031v1
[3] L.R.U. Manssur, R. Portugal "Group-theoretic Approach for Symbolic
Tensor Manipulation: II. Dummy Indices"
arXiv:math-ph/0107032v1
[4] xperm.c part of XPerm written by J. M. Martin-Garcia
http://www.xact.es/index.html
"""
def dummy_sgs(dummies, sym, n):
"""
Return the strong generators for dummy indices
Parameters
==========
dummies : list of dummy indices
`dummies[2k], dummies[2k+1]` are paired indices
sym : symmetry under interchange of contracted dummies::
* None no symmetry
* 0 commuting
* 1 anticommuting
n : number of indices
in base form the dummy indices are always in consecutive positions
Examples
========
>>> from sympy.combinatorics.tensor_can import dummy_sgs
>>> dummy_sgs(list(range(2, 8)), 0, 8)
[[0, 1, 3, 2, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 5, 4, 6, 7, 8, 9],
[0, 1, 2, 3, 4, 5, 7, 6, 8, 9], [0, 1, 4, 5, 2, 3, 6, 7, 8, 9],
[0, 1, 2, 3, 6, 7, 4, 5, 8, 9]]
"""
if len(dummies) > n:
raise ValueError("List too large")
res = []
# exchange of contravariant and covariant indices
if sym is not None:
for j in dummies[::2]:
a = list(range(n + 2))
if sym == 1:
a[n] = n + 1
a[n + 1] = n
a[j], a[j + 1] = a[j + 1], a[j]
res.append(a)
# rename dummy indices
for j in dummies[:-3:2]:
a = list(range(n + 2))
a[j:j + 4] = a[j + 2], a[j + 3], a[j], a[j + 1]
res.append(a)
return res
def _min_dummies(dummies, sym, indices):
"""
Return list of minima of the orbits of indices in group of dummies
see `double_coset_can_rep` for the description of `dummies` and `sym`
indices is the initial list of dummy indices
Examples
========
>>> from sympy.combinatorics.tensor_can import _min_dummies
>>> _min_dummies([list(range(2, 8))], [0], list(range(10)))
[0, 1, 2, 2, 2, 2, 2, 2, 8, 9]
"""
num_types = len(sym)
m = []
for dx in dummies:
if dx:
m.append(min(dx))
else:
m.append(None)
res = indices[:]
for i in range(num_types):
for c, i in enumerate(indices):
for j in range(num_types):
if i in dummies[j]:
res[c] = m[j]
break
return res
def _trace_S(s, j, b, S_cosets):
"""
Return the representative h satisfying s[h[b]] == j
If there is not such a representative return None
"""
for h in S_cosets[b]:
if s[h[b]] == j:
return h
return None
def _trace_D(gj, p_i, Dxtrav):
"""
Return the representative h satisfying h[gj] == p_i
If there is not such a representative return None
"""
for h in Dxtrav:
if h[gj] == p_i:
return h
return None
def _dumx_remove(dumx, dumx_flat, p0):
"""
remove p0 from dumx
"""
res = []
for dx in dumx:
if p0 not in dx:
res.append(dx)
continue
k = dx.index(p0)
if k % 2 == 0:
p0_paired = dx[k + 1]
else:
p0_paired = dx[k - 1]
dx.remove(p0)
dx.remove(p0_paired)
dumx_flat.remove(p0)
dumx_flat.remove(p0_paired)
res.append(dx)
def transversal2coset(size, base, transversal):
a = []
j = 0
for i in range(size):
if i in base:
a.append(sorted(transversal[j].values()))
j += 1
else:
a.append([list(range(size))])
j = len(a) - 1
while a[j] == [list(range(size))]:
j -= 1
return a[:j + 1]
def double_coset_can_rep(dummies, sym, b_S, sgens, S_transversals, g):
"""
Butler-Portugal algorithm for tensor canonicalization with dummy indices
dummies
list of lists of dummy indices,
one list for each type of index;
the dummy indices are put in order contravariant, covariant
[d0, -d0, d1, -d1, ...].
sym
list of the symmetries of the index metric for each type.
possible symmetries of the metrics
* 0 symmetric
* 1 antisymmetric
* None no symmetry
b_S
base of a minimal slot symmetry BSGS.
sgens
generators of the slot symmetry BSGS.
S_transversals
transversals for the slot BSGS.
g
permutation representing the tensor.
Return 0 if the tensor is zero, else return the array form of
the permutation representing the canonical form of the tensor.
A tensor with dummy indices can be represented in a number
of equivalent ways which typically grows exponentially with
the number of indices. To be able to establish if two tensors
with many indices are equal becomes computationally very slow
in absence of an efficient algorithm.
The Butler-Portugal algorithm [3] is an efficient algorithm to
put tensors in canonical form, solving the above problem.
Portugal observed that a tensor can be represented by a permutation,
and that the class of tensors equivalent to it under slot and dummy
symmetries is equivalent to the double coset `D*g*S`
(Note: in this documentation we use the conventions for multiplication
of permutations p, q with (p*q)(i) = p[q[i]] which is opposite
to the one used in the Permutation class)
Using the algorithm by Butler to find a representative of the
double coset one can find a canonical form for the tensor.
To see this correspondence,
let `g` be a permutation in array form; a tensor with indices `ind`
(the indices including both the contravariant and the covariant ones)
can be written as
`t = T(ind[g[0],..., ind[g[n-1]])`,
where `n= len(ind)`;
`g` has size `n + 2`, the last two indices for the sign of the tensor
(trick introduced in [4]).
A slot symmetry transformation `s` is a permutation acting on the slots
`t -> T(ind[(g*s)[0]],..., ind[(g*s)[n-1]])`
A dummy symmetry transformation acts on `ind`
`t -> T(ind[(d*g)[0]],..., ind[(d*g)[n-1]])`
Being interested only in the transformations of the tensor under
these symmetries, one can represent the tensor by `g`, which transforms
as
`g -> d*g*s`, so it belongs to the coset `D*g*S`.
Let us explain the conventions by an example.
Given a tensor `T^{d3 d2 d1}{}_{d1 d2 d3}` with the slot symmetries
`T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a4 a1 a2 a3 a0 a5}`
and symmetric metric, find the tensor equivalent to it which
is the lowest under the ordering of indices:
lexicographic ordering `d1, d2, d3` then and contravariant index
before covariant index; that is the canonical form of the tensor.
The canonical form is `-T^{d1 d2 d3}{}_{d1 d2 d3}`
obtained using `T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`.
To convert this problem in the input for this function,
use the following labelling of the index names
(- for covariant for short) `d1, -d1, d2, -d2, d3, -d3`
`T^{d3 d2 d1}{}_{d1 d2 d3}` corresponds to `g = [4, 2, 0, 1, 3, 5, 6, 7]`
where the last two indices are for the sign
`sgens = [Permutation(0, 2)(6, 7), Permutation(0, 4)(6, 7)]`
sgens[0] is the slot symmetry `-(0, 2)`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a2 a1 a0 a3 a4 a5}`
sgens[1] is the slot symmetry `-(0, 4)`
`T^{a0 a1 a2 a3 a4 a5} = -T^{a4 a1 a2 a3 a0 a5}`
The dummy symmetry group D is generated by the strong base generators
`[(0, 1), (2, 3), (4, 5), (0, 1)(2, 3),(2, 3)(4, 5)]`
The dummy symmetry acts from the left
`d = [1, 0, 2, 3, 4, 5, 6, 7]` exchange `d1 -> -d1`
`T^{d3 d2 d1}{}_{d1 d2 d3} == T^{d3 d2}{}_{d1}{}^{d1}{}_{d2 d3}`
`g=[4, 2, 0, 1, 3, 5, 6, 7] -> [4, 2, 1, 0, 3, 5, 6, 7] = _af_rmul(d, g)`
which differs from `_af_rmul(g, d)`.
The slot symmetry acts from the right
`s = [2, 1, 0, 3, 4, 5, 7, 6]` exchanges slots 0 and 2 and changes sign
`T^{d3 d2 d1}{}_{d1 d2 d3} == -T^{d1 d2 d3}{}_{d1 d2 d3}`
`g=[4,2,0,1,3,5,6,7] -> [0, 2, 4, 1, 3, 5, 7, 6] = _af_rmul(g, s)`
Example in which the tensor is zero, same slot symmetries as above:
`T^{d3}{}_{d1,d2}{}^{d1}{}_{d3}{}^{d2}`
`= -T^{d3}{}_{d1,d3}{}^{d1}{}_{d2}{}^{d2}` under slot symmetry `-(2,4)`;
`= T_{d3 d1}{}^{d3}{}^{d1}{}_{d2}{}^{d2}` under slot symmetry `-(0,2)`;
`= T^{d3}{}_{d1 d3}{}^{d1}{}_{d2}{}^{d2}` symmetric metric;
`= 0` since two of these lines have tensors differ only for the sign.
The double coset D*g*S consists of permutations `h = d*g*s` corresponding
to equivalent tensors; if there are two `h` which are the same apart
from the sign, return zero; otherwise
choose as representative the tensor with indices
ordered lexicographically according to `[d1, -d1, d2, -d2, d3, -d3]`
that is `rep = min(D*g*S) = min([d*g*s for d in D for s in S])`
The indices are fixed one by one; first choose the lowest index
for slot 0, then the lowest remaining index for slot 1, etc.
Doing this one obtains a chain of stabilizers
`S -> S_{b0} -> S_{b0,b1} -> ...` and
`D -> D_{p0} -> D_{p0,p1} -> ...`
where `[b0, b1, ...] = range(b)` is a base of the symmetric group;
the strong base `b_S` of S is an ordered sublist of it;
therefore it is sufficient to compute once the
strong base generators of S using the Schreier-Sims algorithm;
the stabilizers of the strong base generators are the
strong base generators of the stabilizer subgroup.
`dbase = [p0, p1, ...]` is not in general in lexicographic order,
so that one must recompute the strong base generators each time;
however this is trivial, there is no need to use the Schreier-Sims
algorithm for D.
The algorithm keeps a TAB of elements `(s_i, d_i, h_i)`
where `h_i = d_i*g*s_i` satisfying `h_i[j] = p_j` for `0 <= j < i`
starting from `s_0 = id, d_0 = id, h_0 = g`.
The equations `h_0[0] = p_0, h_1[1] = p_1,...` are solved in this order,
choosing each time the lowest possible value of p_i
For `j < i`
`d_i*g*s_i*S_{b_0,...,b_{i-1}}*b_j = D_{p_0,...,p_{i-1}}*p_j`
so that for dx in `D_{p_0,...,p_{i-1}}` and sx in
`S_{base[0],...,base[i-1]}` one has `dx*d_i*g*s_i*sx*b_j = p_j`
Search for dx, sx such that this equation holds for `j = i`;
it can be written as `s_i*sx*b_j = J, dx*d_i*g*J = p_j`
`sx*b_j = s_i**-1*J; sx = trace(s_i**-1, S_{b_0,...,b_{i-1}})`
`dx**-1*p_j = d_i*g*J; dx = trace(d_i*g*J, D_{p_0,...,p_{i-1}})`
`s_{i+1} = s_i*trace(s_i**-1*J, S_{b_0,...,b_{i-1}})`
`d_{i+1} = trace(d_i*g*J, D_{p_0,...,p_{i-1}})**-1*d_i`
`h_{i+1}*b_i = d_{i+1}*g*s_{i+1}*b_i = p_i`
`h_n*b_j = p_j` for all j, so that `h_n` is the solution.
Add the found `(s, d, h)` to TAB1.
At the end of the iteration sort TAB1 with respect to the `h`;
if there are two consecutive `h` in TAB1 which differ only for the
sign, the tensor is zero, so return 0;
if there are two consecutive `h` which are equal, keep only one.
Then stabilize the slot generators under `i` and the dummy generators
under `p_i`.
Assign `TAB = TAB1` at the end of the iteration step.
At the end `TAB` contains a unique `(s, d, h)`, since all the slots
of the tensor `h` have been fixed to have the minimum value according
to the symmetries. The algorithm returns `h`.
It is important that the slot BSGS has lexicographic minimal base,
otherwise there is an `i` which does not belong to the slot base
for which `p_i` is fixed by the dummy symmetry only, while `i`
is not invariant from the slot stabilizer, so `p_i` is not in
general the minimal value.
This algorithm differs slightly from the original algorithm [3]:
the canonical form is minimal lexicographically, and
the BSGS has minimal base under lexicographic order.
Equal tensors `h` are eliminated from TAB.
Examples
========
>>> from sympy.combinatorics.permutations import Permutation
>>> from sympy.combinatorics.perm_groups import PermutationGroup
>>> from sympy.combinatorics.tensor_can import double_coset_can_rep, get_transversals
>>> gens = [Permutation(x) for x in [[2, 1, 0, 3, 4, 5, 7, 6], [4, 1, 2, 3, 0, 5, 7, 6]]]
>>> base = [0, 2]
>>> g = Permutation([4, 2, 0, 1, 3, 5, 6, 7])
>>> transversals = get_transversals(base, gens)
>>> double_coset_can_rep([list(range(6))], [0], base, gens, transversals, g)
[0, 1, 2, 3, 4, 5, 7, 6]
>>> g = Permutation([4, 1, 3, 0, 5, 2, 6, 7])
>>> double_coset_can_rep([list(range(6))], [0], base, gens, transversals, g)
0
"""
size = g.size
g = g.array_form
num_dummies = size - 2
indices = list(range(num_dummies))
all_metrics_with_sym = all([_ is not None for _ in sym])
num_types = len(sym)
dumx = dummies[:]
dumx_flat = []
for dx in dumx:
dumx_flat.extend(dx)
b_S = b_S[:]
sgensx = [h._array_form for h in sgens]
if b_S:
S_transversals = transversal2coset(size, b_S, S_transversals)
# strong generating set for D
dsgsx = []
for i in range(num_types):
dsgsx.extend(dummy_sgs(dumx[i], sym[i], num_dummies))
ginv = _af_invert(g)
idn = list(range(size))
# TAB = list of entries (s, d, h) where h = _af_rmuln(d,g,s)
# for short, in the following d*g*s means _af_rmuln(d,g,s)
TAB = [(idn, idn, g)]
for i in range(size - 2):
b = i
testb = b in b_S and sgensx
if testb:
sgensx1 = [_af_new(_) for _ in sgensx]
deltab = _orbit(size, sgensx1, b)
else:
deltab = {b}
# p1 = min(IMAGES) = min(Union D_p*h*deltab for h in TAB)
if all_metrics_with_sym:
md = _min_dummies(dumx, sym, indices)
else:
md = [min(_orbit(size, [_af_new(
ddx) for ddx in dsgsx], ii)) for ii in range(size - 2)]
p_i = min([min([md[h[x]] for x in deltab]) for s, d, h in TAB])
dsgsx1 = [_af_new(_) for _ in dsgsx]
Dxtrav = _orbit_transversal(size, dsgsx1, p_i, False, af=True) \
if dsgsx else None
if Dxtrav:
Dxtrav = [_af_invert(x) for x in Dxtrav]
# compute the orbit of p_i
for ii in range(num_types):
if p_i in dumx[ii]:
# the orbit is made by all the indices in dum[ii]
if sym[ii] is not None:
deltap = dumx[ii]
else:
# the orbit is made by all the even indices if p_i
# is even, by all the odd indices if p_i is odd
p_i_index = dumx[ii].index(p_i) % 2
deltap = dumx[ii][p_i_index::2]
break
else:
deltap = [p_i]
TAB1 = []
nTAB = len(TAB)
while TAB:
s, d, h = TAB.pop()
if min([md[h[x]] for x in deltab]) != p_i:
continue
deltab1 = [x for x in deltab if md[h[x]] == p_i]
# NEXT = s*deltab1 intersection (d*g)**-1*deltap
dg = _af_rmul(d, g)
dginv = _af_invert(dg)
sdeltab = [s[x] for x in deltab1]
gdeltap = [dginv[x] for x in deltap]
NEXT = [x for x in sdeltab if x in gdeltap]
# d, s satisfy
# d*g*s*base[i-1] = p_{i-1}; using the stabilizers
# d*g*s*S_{base[0],...,base[i-1]}*base[i-1] =
# D_{p_0,...,p_{i-1}}*p_{i-1}
# so that to find d1, s1 satisfying d1*g*s1*b = p_i
# one can look for dx in D_{p_0,...,p_{i-1}} and
# sx in S_{base[0],...,base[i-1]}
# d1 = dx*d; s1 = s*sx
# d1*g*s1*b = dx*d*g*s*sx*b = p_i
for j in NEXT:
if testb:
# solve s1*b = j with s1 = s*sx for some element sx
# of the stabilizer of ..., base[i-1]
# sx*b = s**-1*j; sx = _trace_S(s, j,...)
# s1 = s*trace_S(s**-1*j,...)
s1 = _trace_S(s, j, b, S_transversals)
if not s1:
continue
else:
s1 = [s[ix] for ix in s1]
else:
s1 = s
# assert s1[b] == j # invariant
# solve d1*g*j = p_i with d1 = dx*d for some element dg
# of the stabilizer of ..., p_{i-1}
# dx**-1*p_i = d*g*j; dx**-1 = trace_D(d*g*j,...)
# d1 = trace_D(d*g*j,...)**-1*d
# to save an inversion in the inner loop; notice we did
# Dxtrav = [perm_af_invert(x) for x in Dxtrav] out of the loop
if Dxtrav:
d1 = _trace_D(dg[j], p_i, Dxtrav)
if not d1:
continue
else:
if p_i != dg[j]:
continue
d1 = idn
assert d1[dg[j]] == p_i # invariant
d1 = [d1[ix] for ix in d]
h1 = [d1[g[ix]] for ix in s1]
# assert h1[b] == p_i # invariant
TAB1.append((s1, d1, h1))
# if TAB contains equal permutations, keep only one of them;
# if TAB contains equal permutations up to the sign, return 0
TAB1.sort(key=lambda x: x[-1])
nTAB1 = len(TAB1)
prev = [0] * size
while TAB1:
s, d, h = TAB1.pop()
if h[:-2] == prev[:-2]:
if h[-1] != prev[-1]:
return 0
else:
TAB.append((s, d, h))
prev = h
# stabilize the SGS
sgensx = [h for h in sgensx if h[b] == b]
if b in b_S:
b_S.remove(b)
_dumx_remove(dumx, dumx_flat, p_i)
dsgsx = []
for i in range(num_types):
dsgsx.extend(dummy_sgs(dumx[i], sym[i], num_dummies))
return TAB[0][-1]
def canonical_free(base, gens, g, num_free):
"""
canonicalization of a tensor with respect to free indices
choosing the minimum with respect to lexicographical ordering
in the free indices
``base``, ``gens`` BSGS for slot permutation group
``g`` permutation representing the tensor
``num_free`` number of free indices
The indices must be ordered with first the free indices
see explanation in double_coset_can_rep
The algorithm is a variation of the one given in [2].
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import canonical_free
>>> gens = [[1, 0, 2, 3, 5, 4], [2, 3, 0, 1, 4, 5],[0, 1, 3, 2, 5, 4]]
>>> gens = [Permutation(h) for h in gens]
>>> base = [0, 2]
>>> g = Permutation([2, 1, 0, 3, 4, 5])
>>> canonical_free(base, gens, g, 4)
[0, 3, 1, 2, 5, 4]
Consider the product of Riemann tensors
``T = R^{a}_{d0}^{d1,d2}*R_{d2,d1}^{d0,b}``
The order of the indices is ``[a, b, d0, -d0, d1, -d1, d2, -d2]``
The permutation corresponding to the tensor is
``g = [0, 3, 4, 6, 7, 5, 2, 1, 8, 9]``
In particular ``a`` is position ``0``, ``b`` is in position ``9``.
Use the slot symmetries to get `T` is a form which is the minimal
in lexicographic order in the free indices ``a`` and ``b``, e.g.
``-R^{a}_{d0}^{d1,d2}*R^{b,d0}_{d2,d1}`` corresponding to
``[0, 3, 4, 6, 1, 2, 7, 5, 9, 8]``
>>> from sympy.combinatorics.tensor_can import riemann_bsgs, tensor_gens
>>> base, gens = riemann_bsgs
>>> size, sbase, sgens = tensor_gens(base, gens, [[], []], 0)
>>> g = Permutation([0, 3, 4, 6, 7, 5, 2, 1, 8, 9])
>>> canonical_free(sbase, [Permutation(h) for h in sgens], g, 2)
[0, 3, 4, 6, 1, 2, 7, 5, 9, 8]
"""
g = g.array_form
size = len(g)
if not base:
return g[:]
transversals = get_transversals(base, gens)
m = len(base)
for x in sorted(g[:-2]):
if x not in base:
base.append(x)
h = g
for i, transv in enumerate(transversals):
b = base[i]
h_i = [size]*num_free
# find the element s in transversals[i] such that
# _af_rmul(h, s) has its free elements with the lowest position in h
s = None
for sk in transv.values():
h1 = _af_rmul(h, sk)
hi = [h1.index(ix) for ix in range(num_free)]
if hi < h_i:
h_i = hi
s = sk
if s:
h = _af_rmul(h, s)
return h
def _get_map_slots(size, fixed_slots):
res = list(range(size))
pos = 0
for i in range(size):
if i in fixed_slots:
continue
res[i] = pos
pos += 1
return res
def _lift_sgens(size, fixed_slots, free, s):
a = []
j = k = 0
fd = list(zip(fixed_slots, free))
fd = [y for x, y in sorted(fd)]
num_free = len(free)
for i in range(size):
if i in fixed_slots:
a.append(fd[k])
k += 1
else:
a.append(s[j] + num_free)
j += 1
return a
def canonicalize(g, dummies, msym, *v):
"""
canonicalize tensor formed by tensors
Parameters
==========
g : permutation representing the tensor
dummies : list representing the dummy indices
it can be a list of dummy indices of the same type
or a list of lists of dummy indices, one list for each
type of index;
the dummy indices must come after the free indices,
and put in order contravariant, covariant
[d0, -d0, d1,-d1,...]
msym : symmetry of the metric(s)
it can be an integer or a list;
in the first case it is the symmetry of the dummy index metric;
in the second case it is the list of the symmetries of the
index metric for each type
v : list, (base_i, gens_i, n_i, sym_i) for tensors of type `i`
base_i, gens_i : BSGS for tensors of this type.
The BSGS should have minimal base under lexicographic ordering;
if not, an attempt is made do get the minimal BSGS;
in case of failure,
canonicalize_naive is used, which is much slower.
n_i : number of tensors of type `i`.
sym_i : symmetry under exchange of component tensors of type `i`.
Both for msym and sym_i the cases are
* None no symmetry
* 0 commuting
* 1 anticommuting
Returns
=======
0 if the tensor is zero, else return the array form of
the permutation representing the canonical form of the tensor.
Algorithm
=========
First one uses canonical_free to get the minimum tensor under
lexicographic order, using only the slot symmetries.
If the component tensors have not minimal BSGS, it is attempted
to find it; if the attempt fails canonicalize_naive
is used instead.
Compute the residual slot symmetry keeping fixed the free indices
using tensor_gens(base, gens, list_free_indices, sym).
Reduce the problem eliminating the free indices.
Then use double_coset_can_rep and lift back the result reintroducing
the free indices.
Examples
========
one type of index with commuting metric;
`A_{a b}` and `B_{a b}` antisymmetric and commuting
`T = A_{d0 d1} * B^{d0}{}_{d2} * B^{d2 d1}`
`ord = [d0,-d0,d1,-d1,d2,-d2]` order of the indices
g = [1, 3, 0, 5, 4, 2, 6, 7]
`T_c = 0`
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs, canonicalize, bsgs_direct_product
>>> from sympy.combinatorics import Permutation
>>> base2a, gens2a = get_symmetric_group_sgs(2, 1)
>>> t0 = (base2a, gens2a, 1, 0)
>>> t1 = (base2a, gens2a, 2, 0)
>>> g = Permutation([1, 3, 0, 5, 4, 2, 6, 7])
>>> canonicalize(g, range(6), 0, t0, t1)
0
same as above, but with `B_{a b}` anticommuting
`T_c = -A^{d0 d1} * B_{d0}{}^{d2} * B_{d1 d2}`
can = [0,2,1,4,3,5,7,6]
>>> t1 = (base2a, gens2a, 2, 1)
>>> canonicalize(g, range(6), 0, t0, t1)
[0, 2, 1, 4, 3, 5, 7, 6]
two types of indices `[a,b,c,d,e,f]` and `[m,n]`, in this order,
both with commuting metric
`f^{a b c}` antisymmetric, commuting
`A_{m a}` no symmetry, commuting
`T = f^c{}_{d a} * f^f{}_{e b} * A_m{}^d * A^{m b} * A_n{}^a * A^{n e}`
ord = [c,f,a,-a,b,-b,d,-d,e,-e,m,-m,n,-n]
g = [0,7,3, 1,9,5, 11,6, 10,4, 13,2, 12,8, 14,15]
The canonical tensor is
`T_c = -f^{c a b} * f^{f d e} * A^m{}_a * A_{m d} * A^n{}_b * A_{n e}`
can = [0,2,4, 1,6,8, 10,3, 11,7, 12,5, 13,9, 15,14]
>>> base_f, gens_f = get_symmetric_group_sgs(3, 1)
>>> base1, gens1 = get_symmetric_group_sgs(1)
>>> base_A, gens_A = bsgs_direct_product(base1, gens1, base1, gens1)
>>> t0 = (base_f, gens_f, 2, 0)
>>> t1 = (base_A, gens_A, 4, 0)
>>> dummies = [range(2, 10), range(10, 14)]
>>> g = Permutation([0, 7, 3, 1, 9, 5, 11, 6, 10, 4, 13, 2, 12, 8, 14, 15])
>>> canonicalize(g, dummies, [0, 0], t0, t1)
[0, 2, 4, 1, 6, 8, 10, 3, 11, 7, 12, 5, 13, 9, 15, 14]
"""
from sympy.combinatorics.testutil import canonicalize_naive
if not isinstance(msym, list):
if not msym in [0, 1, None]:
raise ValueError('msym must be 0, 1 or None')
num_types = 1
else:
num_types = len(msym)
if not all(msymx in [0, 1, None] for msymx in msym):
raise ValueError('msym entries must be 0, 1 or None')
if len(dummies) != num_types:
raise ValueError(
'dummies and msym must have the same number of elements')
size = g.size
num_tensors = 0
v1 = []
for i in range(len(v)):
base_i, gens_i, n_i, sym_i = v[i]
# check that the BSGS is minimal;
# this property is used in double_coset_can_rep;
# if it is not minimal use canonicalize_naive
if not _is_minimal_bsgs(base_i, gens_i):
mbsgs = get_minimal_bsgs(base_i, gens_i)
if not mbsgs:
can = canonicalize_naive(g, dummies, msym, *v)
return can
base_i, gens_i = mbsgs
v1.append((base_i, gens_i, [[]] * n_i, sym_i))
num_tensors += n_i
if num_types == 1 and not isinstance(msym, list):
dummies = [dummies]
msym = [msym]
flat_dummies = []
for dumx in dummies:
flat_dummies.extend(dumx)
if flat_dummies and flat_dummies != list(range(flat_dummies[0], flat_dummies[-1] + 1)):
raise ValueError('dummies is not valid')
# slot symmetry of the tensor
size1, sbase, sgens = gens_products(*v1)
if size != size1:
raise ValueError(
'g has size %d, generators have size %d' % (size, size1))
free = [i for i in range(size - 2) if i not in flat_dummies]
num_free = len(free)
# g1 minimal tensor under slot symmetry
g1 = canonical_free(sbase, sgens, g, num_free)
if not flat_dummies:
return g1
# save the sign of g1
sign = 0 if g1[-1] == size - 1 else 1
# the free indices are kept fixed.
# Determine free_i, the list of slots of tensors which are fixed
# since they are occupied by free indices, which are fixed.
start = 0
for i in range(len(v)):
free_i = []
base_i, gens_i, n_i, sym_i = v[i]
len_tens = gens_i[0].size - 2
# for each component tensor get a list od fixed islots
for j in range(n_i):
# get the elements corresponding to the component tensor
h = g1[start:(start + len_tens)]
fr = []
# get the positions of the fixed elements in h
for k in free:
if k in h:
fr.append(h.index(k))
free_i.append(fr)
start += len_tens
v1[i] = (base_i, gens_i, free_i, sym_i)
# BSGS of the tensor with fixed free indices
# if tensor_gens fails in gens_product, use canonicalize_naive
size, sbase, sgens = gens_products(*v1)
# reduce the permutations getting rid of the free indices
pos_dummies = [g1.index(x) for x in flat_dummies]
pos_free = [g1.index(x) for x in range(num_free)]
size_red = size - num_free
g1_red = [x - num_free for x in g1 if x in flat_dummies]
if sign:
g1_red.extend([size_red - 1, size_red - 2])
else:
g1_red.extend([size_red - 2, size_red - 1])
map_slots = _get_map_slots(size, pos_free)
sbase_red = [map_slots[i] for i in sbase if i not in pos_free]
sgens_red = [_af_new([map_slots[i] for i in y._array_form if i not in pos_free]) for y in sgens]
dummies_red = [[x - num_free for x in y] for y in dummies]
transv_red = get_transversals(sbase_red, sgens_red)
g1_red = _af_new(g1_red)
g2 = double_coset_can_rep(
dummies_red, msym, sbase_red, sgens_red, transv_red, g1_red)
if g2 == 0:
return 0
# lift to the case with the free indices
g3 = _lift_sgens(size, pos_free, free, g2)
return g3
def perm_af_direct_product(gens1, gens2, signed=True):
"""
direct products of the generators gens1 and gens2
Examples
========
>>> from sympy.combinatorics.tensor_can import perm_af_direct_product
>>> gens1 = [[1, 0, 2, 3], [0, 1, 3, 2]]
>>> gens2 = [[1, 0]]
>>> perm_af_direct_product(gens1, gens2, False)
[[1, 0, 2, 3, 4, 5], [0, 1, 3, 2, 4, 5], [0, 1, 2, 3, 5, 4]]
>>> gens1 = [[1, 0, 2, 3, 5, 4], [0, 1, 3, 2, 4, 5]]
>>> gens2 = [[1, 0, 2, 3]]
>>> perm_af_direct_product(gens1, gens2, True)
[[1, 0, 2, 3, 4, 5, 7, 6], [0, 1, 3, 2, 4, 5, 6, 7], [0, 1, 2, 3, 5, 4, 6, 7]]
"""
gens1 = [list(x) for x in gens1]
gens2 = [list(x) for x in gens2]
s = 2 if signed else 0
n1 = len(gens1[0]) - s
n2 = len(gens2[0]) - s
start = list(range(n1))
end = list(range(n1, n1 + n2))
if signed:
gens1 = [gen[:-2] + end + [gen[-2] + n2, gen[-1] + n2]
for gen in gens1]
gens2 = [start + [x + n1 for x in gen] for gen in gens2]
else:
gens1 = [gen + end for gen in gens1]
gens2 = [start + [x + n1 for x in gen] for gen in gens2]
res = gens1 + gens2
return res
def bsgs_direct_product(base1, gens1, base2, gens2, signed=True):
"""
direct product of two BSGS
base1 base of the first BSGS.
gens1 strong generating sequence of the first BSGS.
base2, gens2 similarly for the second BSGS.
signed flag for signed permutations.
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import (get_symmetric_group_sgs, bsgs_direct_product)
>>> Permutation.print_cyclic = True
>>> base1, gens1 = get_symmetric_group_sgs(1)
>>> base2, gens2 = get_symmetric_group_sgs(2)
>>> bsgs_direct_product(base1, gens1, base2, gens2)
([1], [(4)(1 2)])
"""
s = 2 if signed else 0
n1 = gens1[0].size - s
base = list(base1)
base += [x + n1 for x in base2]
gens1 = [h._array_form for h in gens1]
gens2 = [h._array_form for h in gens2]
gens = perm_af_direct_product(gens1, gens2, signed)
size = len(gens[0])
id_af = list(range(size))
gens = [h for h in gens if h != id_af]
if not gens:
gens = [id_af]
return base, [_af_new(h) for h in gens]
def get_symmetric_group_sgs(n, antisym=False):
"""
Return base, gens of the minimal BSGS for (anti)symmetric tensor
``n`` rank of the tensor
``antisym = False`` symmetric tensor
``antisym = True`` antisymmetric tensor
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs
>>> Permutation.print_cyclic = True
>>> get_symmetric_group_sgs(3)
([0, 1], [(4)(0 1), (4)(1 2)])
"""
if n == 1:
return [], [_af_new(list(range(3)))]
gens = [Permutation(n - 1)(i, i + 1)._array_form for i in range(n - 1)]
if antisym == 0:
gens = [x + [n, n + 1] for x in gens]
else:
gens = [x + [n + 1, n] for x in gens]
base = list(range(n - 1))
return base, [_af_new(h) for h in gens]
riemann_bsgs = [0, 2], [Permutation(0, 1)(4, 5), Permutation(2, 3)(4, 5),
Permutation(5)(0, 2)(1, 3)]
def get_transversals(base, gens):
"""
Return transversals for the group with BSGS base, gens
"""
if not base:
return []
stabs = _distribute_gens_by_base(base, gens)
orbits, transversals = _orbits_transversals_from_bsgs(base, stabs)
transversals = [{x: h._array_form for x, h in y.items()} for y in
transversals]
return transversals
def _is_minimal_bsgs(base, gens):
"""
Check if the BSGS has minimal base under lexigographic order.
base, gens BSGS
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import riemann_bsgs, _is_minimal_bsgs
>>> _is_minimal_bsgs(*riemann_bsgs)
True
>>> riemann_bsgs1 = ([2, 0], ([Permutation(5)(0, 1)(4, 5), Permutation(5)(0, 2)(1, 3)]))
>>> _is_minimal_bsgs(*riemann_bsgs1)
False
"""
base1 = []
sgs1 = gens[:]
size = gens[0].size
for i in range(size):
if not all(h._array_form[i] == i for h in sgs1):
base1.append(i)
sgs1 = [h for h in sgs1 if h._array_form[i] == i]
return base1 == base
def get_minimal_bsgs(base, gens):
"""
Compute a minimal GSGS
base, gens BSGS
If base, gens is a minimal BSGS return it; else return a minimal BSGS
if it fails in finding one, it returns None
TODO: use baseswap in the case in which if it fails in finding a
minimal BSGS
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import get_minimal_bsgs
>>> Permutation.print_cyclic = True
>>> riemann_bsgs1 = ([2, 0], ([Permutation(5)(0, 1)(4, 5), Permutation(5)(0, 2)(1, 3)]))
>>> get_minimal_bsgs(*riemann_bsgs1)
([0, 2], [(0 1)(4 5), (5)(0 2)(1 3), (2 3)(4 5)])
"""
G = PermutationGroup(gens)
base, gens = G.schreier_sims_incremental()
if not _is_minimal_bsgs(base, gens):
return None
return base, gens
def tensor_gens(base, gens, list_free_indices, sym=0):
"""
Returns size, res_base, res_gens BSGS for n tensors of the
same type
base, gens BSGS for tensors of this type
list_free_indices list of the slots occupied by fixed indices
for each of the tensors
sym symmetry under commutation of two tensors
sym None no symmetry
sym 0 commuting
sym 1 anticommuting
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import tensor_gens, get_symmetric_group_sgs
>>> Permutation.print_cyclic = True
two symmetric tensors with 3 indices without free indices
>>> base, gens = get_symmetric_group_sgs(3)
>>> tensor_gens(base, gens, [[], []])
(8, [0, 1, 3, 4], [(7)(0 1), (7)(1 2), (7)(3 4), (7)(4 5), (7)(0 3)(1 4)(2 5)])
two symmetric tensors with 3 indices with free indices in slot 1 and 0
>>> tensor_gens(base, gens, [[1], [0]])
(8, [0, 4], [(7)(0 2), (7)(4 5)])
four symmetric tensors with 3 indices, two of which with free indices
"""
def _get_bsgs(G, base, gens, free_indices):
"""
return the BSGS for G.pointwise_stabilizer(free_indices)
"""
if not free_indices:
return base[:], gens[:]
else:
H = G.pointwise_stabilizer(free_indices)
base, sgs = H.schreier_sims_incremental()
return base, sgs
# if not base there is no slot symmetry for the component tensors
# if list_free_indices.count([]) < 2 there is no commutation symmetry
# so there is no resulting slot symmetry
if not base and list_free_indices.count([]) < 2:
n = len(list_free_indices)
size = gens[0].size
size = n * (gens[0].size - 2) + 2
return size, [], [_af_new(list(range(size)))]
# if any(list_free_indices) one needs to compute the pointwise
# stabilizer, so G is needed
if any(list_free_indices):
G = PermutationGroup(gens)
else:
G = None
# no_free list of lists of indices for component tensors without fixed
# indices
no_free = []
size = gens[0].size
id_af = list(range(size))
num_indices = size - 2
if not list_free_indices[0]:
no_free.append(list(range(num_indices)))
res_base, res_gens = _get_bsgs(G, base, gens, list_free_indices[0])
for i in range(1, len(list_free_indices)):
base1, gens1 = _get_bsgs(G, base, gens, list_free_indices[i])
res_base, res_gens = bsgs_direct_product(res_base, res_gens,
base1, gens1, 1)
if not list_free_indices[i]:
no_free.append(list(range(size - 2, size - 2 + num_indices)))
size += num_indices
nr = size - 2
res_gens = [h for h in res_gens if h._array_form != id_af]
# if sym there are no commuting tensors stop here
if sym is None or not no_free:
if not res_gens:
res_gens = [_af_new(id_af)]
return size, res_base, res_gens
# if the component tensors have moinimal BSGS, so is their direct
# product P; the slot symmetry group is S = P*C, where C is the group
# to (anti)commute the component tensors with no free indices
# a stabilizer has the property S_i = P_i*C_i;
# the BSGS of P*C has SGS_P + SGS_C and the base is
# the ordered union of the bases of P and C.
# If P has minimal BSGS, so has S with this base.
base_comm = []
for i in range(len(no_free) - 1):
ind1 = no_free[i]
ind2 = no_free[i + 1]
a = list(range(ind1[0]))
a.extend(ind2)
a.extend(ind1)
base_comm.append(ind1[0])
a.extend(list(range(ind2[-1] + 1, nr)))
if sym == 0:
a.extend([nr, nr + 1])
else:
a.extend([nr + 1, nr])
res_gens.append(_af_new(a))
res_base = list(res_base)
# each base is ordered; order the union of the two bases
for i in base_comm:
if i not in res_base:
res_base.append(i)
res_base.sort()
if not res_gens:
res_gens = [_af_new(id_af)]
return size, res_base, res_gens
def gens_products(*v):
"""
Returns size, res_base, res_gens BSGS for n tensors of different types
v is a sequence of (base_i, gens_i, free_i, sym_i)
where
base_i, gens_i BSGS of tensor of type `i`
free_i list of the fixed slots for each of the tensors
of type `i`; if there are `n_i` tensors of type `i`
and none of them have fixed slots, `free = [[]]*n_i`
sym 0 (1) if the tensors of type `i` (anti)commute among themselves
Examples
========
>>> from sympy.combinatorics import Permutation
>>> from sympy.combinatorics.tensor_can import get_symmetric_group_sgs, gens_products
>>> Permutation.print_cyclic = True
>>> base, gens = get_symmetric_group_sgs(2)
>>> gens_products((base, gens, [[], []], 0))
(6, [0, 2], [(5)(0 1), (5)(2 3), (5)(0 2)(1 3)])
>>> gens_products((base, gens, [[1], []], 0))
(6, [2], [(5)(2 3)])
"""
res_size, res_base, res_gens = tensor_gens(*v[0])
for i in range(1, len(v)):
size, base, gens = tensor_gens(*v[i])
res_base, res_gens = bsgs_direct_product(res_base, res_gens, base,
gens, 1)
res_size = res_gens[0].size
id_af = list(range(res_size))
res_gens = [h for h in res_gens if h != id_af]
if not res_gens:
res_gens = [id_af]
return res_size, res_base, res_gens
|
4734ebd58861cca631f0a17ff2b6fe4d963e1f198cb93b4b78d35350564f8cd9
|
"""Limits of sequences"""
from __future__ import print_function, division
from sympy.core.sympify import sympify
from sympy.core.singleton import S
from sympy.core.add import Add
from sympy.core.power import Pow
from sympy.core.symbol import Dummy
from sympy.core.function import PoleError
from sympy.series.limits import Limit
from sympy.functions.combinatorial.numbers import fibonacci
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.miscellaneous import Max, Min
from sympy.functions.elementary.trigonometric import cos, sin
def difference_delta(expr, n=None, step=1):
"""Difference Operator.
Discrete analog of differential operator. Given a sequence x[n],
returns the sequence x[n + step] - x[n].
Examples
========
>>> from sympy import difference_delta as dd
>>> from sympy.abc import n
>>> dd(n*(n + 1), n)
2*n + 2
>>> dd(n*(n + 1), n, 2)
4*n + 6
References
==========
.. [1] https://reference.wolfram.com/language/ref/DifferenceDelta.html
"""
expr = sympify(expr)
if n is None:
f = expr.free_symbols
if len(f) == 1:
n = f.pop()
elif len(f) == 0:
return S.Zero
else:
raise ValueError("Since there is more than one variable in the"
" expression, a variable must be supplied to"
" take the difference of %s" % expr)
step = sympify(step)
if step.is_number is False or step.is_finite is False:
raise ValueError("Step should be a finite number.")
if hasattr(expr, '_eval_difference_delta'):
result = expr._eval_difference_delta(n, step)
if result:
return result
return expr.subs(n, n + step) - expr
def dominant(expr, n):
"""Finds the dominant term in a sum, that is a term that dominates
every other term.
If limit(a/b, n, oo) is oo then a dominates b.
If limit(a/b, n, oo) is 0 then b dominates a.
Otherwise, a and b are comparable.
If there is no unique dominant term, then returns ``None``.
Examples
========
>>> from sympy import Sum
>>> from sympy.series.limitseq import dominant
>>> from sympy.abc import n, k
>>> dominant(5*n**3 + 4*n**2 + n + 1, n)
5*n**3
>>> dominant(2**n + Sum(k, (k, 0, n)), n)
2**n
See Also
========
sympy.series.limitseq.dominant
"""
terms = Add.make_args(expr.expand(func=True))
term0 = terms[-1]
comp = [term0] # comparable terms
for t in terms[:-1]:
e = (term0 / t).gammasimp()
l = limit_seq(e, n)
if l is S.Zero:
term0 = t
comp = [term0]
elif l is None:
return None
elif l not in [S.Infinity, -S.Infinity]:
comp.append(t)
if len(comp) > 1:
return None
return term0
def _limit_inf(expr, n):
try:
return Limit(expr, n, S.Infinity).doit(deep=False)
except (NotImplementedError, PoleError):
return None
def _limit_seq(expr, n, trials):
from sympy.concrete.summations import Sum
for i in range(trials):
if not expr.has(Sum):
result = _limit_inf(expr, n)
if result is not None:
return result
num, den = expr.as_numer_denom()
if not den.has(n) or not num.has(n):
result = _limit_inf(expr.doit(), n)
if result is not None:
return result
return None
num, den = (difference_delta(t.expand(), n) for t in [num, den])
expr = (num / den).gammasimp()
if not expr.has(Sum):
result = _limit_inf(expr, n)
if result is not None:
return result
num, den = expr.as_numer_denom()
num = dominant(num, n)
if num is None:
return None
den = dominant(den, n)
if den is None:
return None
expr = (num / den).gammasimp()
def limit_seq(expr, n=None, trials=5):
"""Finds the limit of a sequence as index n tends to infinity.
Parameters
==========
expr : Expr
SymPy expression for the n-th term of the sequence
n : Symbol, optional
The index of the sequence, an integer that tends to positive
infinity. If None, inferred from the expression unless it has
multiple symbols.
trials: int, optional
The algorithm is highly recursive. ``trials`` is a safeguard from
infinite recursion in case the limit is not easily computed by the
algorithm. Try increasing ``trials`` if the algorithm returns ``None``.
Admissible Terms
================
The algorithm is designed for sequences built from rational functions,
indefinite sums, and indefinite products over an indeterminate n. Terms of
alternating sign are also allowed, but more complex oscillatory behavior is
not supported.
Examples
========
>>> from sympy import limit_seq, Sum, binomial
>>> from sympy.abc import n, k, m
>>> limit_seq((5*n**3 + 3*n**2 + 4) / (3*n**3 + 4*n - 5), n)
5/3
>>> limit_seq(binomial(2*n, n) / Sum(binomial(2*k, k), (k, 1, n)), n)
3/4
>>> limit_seq(Sum(k**2 * Sum(2**m/m, (m, 1, k)), (k, 1, n)) / (2**n*n), n)
4
See Also
========
sympy.series.limitseq.dominant
References
==========
.. [1] Computing Limits of Sequences - Manuel Kauers
"""
from sympy.concrete.summations import Sum
from sympy.calculus.util import AccumulationBounds
if n is None:
free = expr.free_symbols
if len(free) == 1:
n = free.pop()
elif not free:
return expr
else:
raise ValueError("Expression has more than one variable. "
"Please specify a variable.")
elif n not in expr.free_symbols:
return expr
expr = expr.rewrite(fibonacci, S.GoldenRatio)
n_ = Dummy("n", integer=True, positive=True)
n1 = Dummy("n", odd=True, positive=True)
n2 = Dummy("n", even=True, positive=True)
# If there is a negative term raised to a power involving n, or a
# trigonometric function, then consider even and odd n separately.
powers = (p.as_base_exp() for p in expr.atoms(Pow))
if (any(b.is_negative and e.has(n) for b, e in powers) or
expr.has(cos, sin)):
L1 = _limit_seq(expr.xreplace({n: n1}), n1, trials)
if L1 is not None:
L2 = _limit_seq(expr.xreplace({n: n2}), n2, trials)
if L1 != L2:
if L1.is_comparable and L2.is_comparable:
return AccumulationBounds(Min(L1, L2), Max(L1, L2))
else:
return None
else:
L1 = _limit_seq(expr.xreplace({n: n_}), n_, trials)
if L1 is not None:
return L1
else:
if expr.is_Add:
limits = [limit_seq(term, n, trials) for term in expr.args]
if any(result is None for result in limits):
return None
else:
return Add(*limits)
# Maybe the absolute value is easier to deal with (though not if
# it has a Sum). If it tends to 0, the limit is 0.
elif not expr.has(Sum):
if _limit_seq(Abs(expr.xreplace({n: n_})), n_, trials) is S.Zero:
return S.Zero
|
c7fa0906fe00379a376a4b148c1e96de6239e27c35ebeae1f6e6d677af745e25
|
from __future__ import print_function, division
from collections import defaultdict
from sympy.core.cache import cacheit
from sympy.core import (sympify, Basic, S, Expr, expand_mul, factor_terms,
Mul, Dummy, igcd, FunctionClass, Add, symbols, Wild, expand)
from sympy.core.compatibility import reduce, iterable, SYMPY_INTS
from sympy.core.numbers import I, Integer
from sympy.core.function import count_ops, _mexpand
from sympy.functions.elementary.trigonometric import TrigonometricFunction
from sympy.functions.elementary.hyperbolic import HyperbolicFunction
from sympy.functions import sin, cos, exp, cosh, tanh, sinh, tan, cot, coth
from sympy.strategies.core import identity
from sympy.strategies.tree import greedy
from sympy.polys import Poly
from sympy.polys.polyerrors import PolificationFailed
from sympy.polys.polytools import groebner
from sympy.polys.domains import ZZ
from sympy.polys import factor, cancel, parallel_poly_from_expr
from sympy.utilities.misc import debug
def trigsimp_groebner(expr, hints=[], quick=False, order="grlex",
polynomial=False):
"""
Simplify trigonometric expressions using a groebner basis algorithm.
This routine takes a fraction involving trigonometric or hyperbolic
expressions, and tries to simplify it. The primary metric is the
total degree. Some attempts are made to choose the simplest possible
expression of the minimal degree, but this is non-rigorous, and also
very slow (see the ``quick=True`` option).
If ``polynomial`` is set to True, instead of simplifying numerator and
denominator together, this function just brings numerator and denominator
into a canonical form. This is much faster, but has potentially worse
results. However, if the input is a polynomial, then the result is
guaranteed to be an equivalent polynomial of minimal degree.
The most important option is hints. Its entries can be any of the
following:
- a natural number
- a function
- an iterable of the form (func, var1, var2, ...)
- anything else, interpreted as a generator
A number is used to indicate that the search space should be increased.
A function is used to indicate that said function is likely to occur in a
simplified expression.
An iterable is used indicate that func(var1 + var2 + ...) is likely to
occur in a simplified .
An additional generator also indicates that it is likely to occur.
(See examples below).
This routine carries out various computationally intensive algorithms.
The option ``quick=True`` can be used to suppress one particularly slow
step (at the expense of potentially more complicated results, but never at
the expense of increased total degree).
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import sin, tan, cos, sinh, cosh, tanh
>>> from sympy.simplify.trigsimp import trigsimp_groebner
Suppose you want to simplify ``sin(x)*cos(x)``. Naively, nothing happens:
>>> ex = sin(x)*cos(x)
>>> trigsimp_groebner(ex)
sin(x)*cos(x)
This is because ``trigsimp_groebner`` only looks for a simplification
involving just ``sin(x)`` and ``cos(x)``. You can tell it to also try
``2*x`` by passing ``hints=[2]``:
>>> trigsimp_groebner(ex, hints=[2])
sin(2*x)/2
>>> trigsimp_groebner(sin(x)**2 - cos(x)**2, hints=[2])
-cos(2*x)
Increasing the search space this way can quickly become expensive. A much
faster way is to give a specific expression that is likely to occur:
>>> trigsimp_groebner(ex, hints=[sin(2*x)])
sin(2*x)/2
Hyperbolic expressions are similarly supported:
>>> trigsimp_groebner(sinh(2*x)/sinh(x))
2*cosh(x)
Note how no hints had to be passed, since the expression already involved
``2*x``.
The tangent function is also supported. You can either pass ``tan`` in the
hints, to indicate that than should be tried whenever cosine or sine are,
or you can pass a specific generator:
>>> trigsimp_groebner(sin(x)/cos(x), hints=[tan])
tan(x)
>>> trigsimp_groebner(sinh(x)/cosh(x), hints=[tanh(x)])
tanh(x)
Finally, you can use the iterable form to suggest that angle sum formulae
should be tried:
>>> ex = (tan(x) + tan(y))/(1 - tan(x)*tan(y))
>>> trigsimp_groebner(ex, hints=[(tan, x, y)])
tan(x + y)
"""
# TODO
# - preprocess by replacing everything by funcs we can handle
# - optionally use cot instead of tan
# - more intelligent hinting.
# For example, if the ideal is small, and we have sin(x), sin(y),
# add sin(x + y) automatically... ?
# - algebraic numbers ...
# - expressions of lowest degree are not distinguished properly
# e.g. 1 - sin(x)**2
# - we could try to order the generators intelligently, so as to influence
# which monomials appear in the quotient basis
# THEORY
# ------
# Ratsimpmodprime above can be used to "simplify" a rational function
# modulo a prime ideal. "Simplify" mainly means finding an equivalent
# expression of lower total degree.
#
# We intend to use this to simplify trigonometric functions. To do that,
# we need to decide (a) which ring to use, and (b) modulo which ideal to
# simplify. In practice, (a) means settling on a list of "generators"
# a, b, c, ..., such that the fraction we want to simplify is a rational
# function in a, b, c, ..., with coefficients in ZZ (integers).
# (2) means that we have to decide what relations to impose on the
# generators. There are two practical problems:
# (1) The ideal has to be *prime* (a technical term).
# (2) The relations have to be polynomials in the generators.
#
# We typically have two kinds of generators:
# - trigonometric expressions, like sin(x), cos(5*x), etc
# - "everything else", like gamma(x), pi, etc.
#
# Since this function is trigsimp, we will concentrate on what to do with
# trigonometric expressions. We can also simplify hyperbolic expressions,
# but the extensions should be clear.
#
# One crucial point is that all *other* generators really should behave
# like indeterminates. In particular if (say) "I" is one of them, then
# in fact I**2 + 1 = 0 and we may and will compute non-sensical
# expressions. However, we can work with a dummy and add the relation
# I**2 + 1 = 0 to our ideal, then substitute back in the end.
#
# Now regarding trigonometric generators. We split them into groups,
# according to the argument of the trigonometric functions. We want to
# organise this in such a way that most trigonometric identities apply in
# the same group. For example, given sin(x), cos(2*x) and cos(y), we would
# group as [sin(x), cos(2*x)] and [cos(y)].
#
# Our prime ideal will be built in three steps:
# (1) For each group, compute a "geometrically prime" ideal of relations.
# Geometrically prime means that it generates a prime ideal in
# CC[gens], not just ZZ[gens].
# (2) Take the union of all the generators of the ideals for all groups.
# By the geometric primality condition, this is still prime.
# (3) Add further inter-group relations which preserve primality.
#
# Step (1) works as follows. We will isolate common factors in the
# argument, so that all our generators are of the form sin(n*x), cos(n*x)
# or tan(n*x), with n an integer. Suppose first there are no tan terms.
# The ideal [sin(x)**2 + cos(x)**2 - 1] is geometrically prime, since
# X**2 + Y**2 - 1 is irreducible over CC.
# Now, if we have a generator sin(n*x), than we can, using trig identities,
# express sin(n*x) as a polynomial in sin(x) and cos(x). We can add this
# relation to the ideal, preserving geometric primality, since the quotient
# ring is unchanged.
# Thus we have treated all sin and cos terms.
# For tan(n*x), we add a relation tan(n*x)*cos(n*x) - sin(n*x) = 0.
# (This requires of course that we already have relations for cos(n*x) and
# sin(n*x).) It is not obvious, but it seems that this preserves geometric
# primality.
# XXX A real proof would be nice. HELP!
# Sketch that <S**2 + C**2 - 1, C*T - S> is a prime ideal of
# CC[S, C, T]:
# - it suffices to show that the projective closure in CP**3 is
# irreducible
# - using the half-angle substitutions, we can express sin(x), tan(x),
# cos(x) as rational functions in tan(x/2)
# - from this, we get a rational map from CP**1 to our curve
# - this is a morphism, hence the curve is prime
#
# Step (2) is trivial.
#
# Step (3) works by adding selected relations of the form
# sin(x + y) - sin(x)*cos(y) - sin(y)*cos(x), etc. Geometric primality is
# preserved by the same argument as before.
def parse_hints(hints):
"""Split hints into (n, funcs, iterables, gens)."""
n = 1
funcs, iterables, gens = [], [], []
for e in hints:
if isinstance(e, (SYMPY_INTS, Integer)):
n = e
elif isinstance(e, FunctionClass):
funcs.append(e)
elif iterable(e):
iterables.append((e[0], e[1:]))
# XXX sin(x+2y)?
# Note: we go through polys so e.g.
# sin(-x) -> -sin(x) -> sin(x)
gens.extend(parallel_poly_from_expr(
[e[0](x) for x in e[1:]] + [e[0](Add(*e[1:]))])[1].gens)
else:
gens.append(e)
return n, funcs, iterables, gens
def build_ideal(x, terms):
"""
Build generators for our ideal. Terms is an iterable with elements of
the form (fn, coeff), indicating that we have a generator fn(coeff*x).
If any of the terms is trigonometric, sin(x) and cos(x) are guaranteed
to appear in terms. Similarly for hyperbolic functions. For tan(n*x),
sin(n*x) and cos(n*x) are guaranteed.
"""
gens = []
I = []
y = Dummy('y')
for fn, coeff in terms:
for c, s, t, rel in (
[cos, sin, tan, cos(x)**2 + sin(x)**2 - 1],
[cosh, sinh, tanh, cosh(x)**2 - sinh(x)**2 - 1]):
if coeff == 1 and fn in [c, s]:
I.append(rel)
elif fn == t:
I.append(t(coeff*x)*c(coeff*x) - s(coeff*x))
elif fn in [c, s]:
cn = fn(coeff*y).expand(trig=True).subs(y, x)
I.append(fn(coeff*x) - cn)
return list(set(I))
def analyse_gens(gens, hints):
"""
Analyse the generators ``gens``, using the hints ``hints``.
The meaning of ``hints`` is described in the main docstring.
Return a new list of generators, and also the ideal we should
work with.
"""
# First parse the hints
n, funcs, iterables, extragens = parse_hints(hints)
debug('n=%s' % n, 'funcs:', funcs, 'iterables:',
iterables, 'extragens:', extragens)
# We just add the extragens to gens and analyse them as before
gens = list(gens)
gens.extend(extragens)
# remove duplicates
funcs = list(set(funcs))
iterables = list(set(iterables))
gens = list(set(gens))
# all the functions we can do anything with
allfuncs = {sin, cos, tan, sinh, cosh, tanh}
# sin(3*x) -> ((3, x), sin)
trigterms = [(g.args[0].as_coeff_mul(), g.func) for g in gens
if g.func in allfuncs]
# Our list of new generators - start with anything that we cannot
# work with (i.e. is not a trigonometric term)
freegens = [g for g in gens if g.func not in allfuncs]
newgens = []
trigdict = {}
for (coeff, var), fn in trigterms:
trigdict.setdefault(var, []).append((coeff, fn))
res = [] # the ideal
for key, val in trigdict.items():
# We have now assembeled a dictionary. Its keys are common
# arguments in trigonometric expressions, and values are lists of
# pairs (fn, coeff). x0, (fn, coeff) in trigdict means that we
# need to deal with fn(coeff*x0). We take the rational gcd of the
# coeffs, call it ``gcd``. We then use x = x0/gcd as "base symbol",
# all other arguments are integral multiples thereof.
# We will build an ideal which works with sin(x), cos(x).
# If hint tan is provided, also work with tan(x). Moreover, if
# n > 1, also work with sin(k*x) for k <= n, and similarly for cos
# (and tan if the hint is provided). Finally, any generators which
# the ideal does not work with but we need to accommodate (either
# because it was in expr or because it was provided as a hint)
# we also build into the ideal.
# This selection process is expressed in the list ``terms``.
# build_ideal then generates the actual relations in our ideal,
# from this list.
fns = [x[1] for x in val]
val = [x[0] for x in val]
gcd = reduce(igcd, val)
terms = [(fn, v/gcd) for (fn, v) in zip(fns, val)]
fs = set(funcs + fns)
for c, s, t in ([cos, sin, tan], [cosh, sinh, tanh]):
if any(x in fs for x in (c, s, t)):
fs.add(c)
fs.add(s)
for fn in fs:
for k in range(1, n + 1):
terms.append((fn, k))
extra = []
for fn, v in terms:
if fn == tan:
extra.append((sin, v))
extra.append((cos, v))
if fn in [sin, cos] and tan in fs:
extra.append((tan, v))
if fn == tanh:
extra.append((sinh, v))
extra.append((cosh, v))
if fn in [sinh, cosh] and tanh in fs:
extra.append((tanh, v))
terms.extend(extra)
x = gcd*Mul(*key)
r = build_ideal(x, terms)
res.extend(r)
newgens.extend(set(fn(v*x) for fn, v in terms))
# Add generators for compound expressions from iterables
for fn, args in iterables:
if fn == tan:
# Tan expressions are recovered from sin and cos.
iterables.extend([(sin, args), (cos, args)])
elif fn == tanh:
# Tanh expressions are recovered from sihn and cosh.
iterables.extend([(sinh, args), (cosh, args)])
else:
dummys = symbols('d:%i' % len(args), cls=Dummy)
expr = fn( Add(*dummys)).expand(trig=True).subs(list(zip(dummys, args)))
res.append(fn(Add(*args)) - expr)
if myI in gens:
res.append(myI**2 + 1)
freegens.remove(myI)
newgens.append(myI)
return res, freegens, newgens
myI = Dummy('I')
expr = expr.subs(S.ImaginaryUnit, myI)
subs = [(myI, S.ImaginaryUnit)]
num, denom = cancel(expr).as_numer_denom()
try:
(pnum, pdenom), opt = parallel_poly_from_expr([num, denom])
except PolificationFailed:
return expr
debug('initial gens:', opt.gens)
ideal, freegens, gens = analyse_gens(opt.gens, hints)
debug('ideal:', ideal)
debug('new gens:', gens, " -- len", len(gens))
debug('free gens:', freegens, " -- len", len(gens))
# NOTE we force the domain to be ZZ to stop polys from injecting generators
# (which is usually a sign of a bug in the way we build the ideal)
if not gens:
return expr
G = groebner(ideal, order=order, gens=gens, domain=ZZ)
debug('groebner basis:', list(G), " -- len", len(G))
# If our fraction is a polynomial in the free generators, simplify all
# coefficients separately:
from sympy.simplify.ratsimp import ratsimpmodprime
if freegens and pdenom.has_only_gens(*set(gens).intersection(pdenom.gens)):
num = Poly(num, gens=gens+freegens).eject(*gens)
res = []
for monom, coeff in num.terms():
ourgens = set(parallel_poly_from_expr([coeff, denom])[1].gens)
# We compute the transitive closure of all generators that can
# be reached from our generators through relations in the ideal.
changed = True
while changed:
changed = False
for p in ideal:
p = Poly(p)
if not ourgens.issuperset(p.gens) and \
not p.has_only_gens(*set(p.gens).difference(ourgens)):
changed = True
ourgens.update(p.exclude().gens)
# NOTE preserve order!
realgens = [x for x in gens if x in ourgens]
# The generators of the ideal have now been (implicitly) split
# into two groups: those involving ourgens and those that don't.
# Since we took the transitive closure above, these two groups
# live in subgrings generated by a *disjoint* set of variables.
# Any sensible groebner basis algorithm will preserve this disjoint
# structure (i.e. the elements of the groebner basis can be split
# similarly), and and the two subsets of the groebner basis then
# form groebner bases by themselves. (For the smaller generating
# sets, of course.)
ourG = [g.as_expr() for g in G.polys if
g.has_only_gens(*ourgens.intersection(g.gens))]
res.append(Mul(*[a**b for a, b in zip(freegens, monom)]) * \
ratsimpmodprime(coeff/denom, ourG, order=order,
gens=realgens, quick=quick, domain=ZZ,
polynomial=polynomial).subs(subs))
return Add(*res)
# NOTE The following is simpler and has less assumptions on the
# groebner basis algorithm. If the above turns out to be broken,
# use this.
return Add(*[Mul(*[a**b for a, b in zip(freegens, monom)]) * \
ratsimpmodprime(coeff/denom, list(G), order=order,
gens=gens, quick=quick, domain=ZZ)
for monom, coeff in num.terms()])
else:
return ratsimpmodprime(
expr, list(G), order=order, gens=freegens+gens,
quick=quick, domain=ZZ, polynomial=polynomial).subs(subs)
_trigs = (TrigonometricFunction, HyperbolicFunction)
def trigsimp(expr, **opts):
"""
reduces expression by using known trig identities
Notes
=====
method:
- Determine the method to use. Valid choices are 'matching' (default),
'groebner', 'combined', and 'fu'. If 'matching', simplify the
expression recursively by targeting common patterns. If 'groebner', apply
an experimental groebner basis algorithm. In this case further options
are forwarded to ``trigsimp_groebner``, please refer to its docstring.
If 'combined', first run the groebner basis algorithm with small
default parameters, then run the 'matching' algorithm. 'fu' runs the
collection of trigonometric transformations described by Fu, et al.
(see the `fu` docstring).
Examples
========
>>> from sympy import trigsimp, sin, cos, log
>>> from sympy.abc import x, y
>>> e = 2*sin(x)**2 + 2*cos(x)**2
>>> trigsimp(e)
2
Simplification occurs wherever trigonometric functions are located.
>>> trigsimp(log(e))
log(2)
Using `method="groebner"` (or `"combined"`) might lead to greater
simplification.
The old trigsimp routine can be accessed as with method 'old'.
>>> from sympy import coth, tanh
>>> t = 3*tanh(x)**7 - 2/coth(x)**7
>>> trigsimp(t, method='old') == t
True
>>> trigsimp(t)
tanh(x)**7
"""
from sympy.simplify.fu import fu
expr = sympify(expr)
try:
return expr._eval_trigsimp(**opts)
except AttributeError:
pass
old = opts.pop('old', False)
if not old:
opts.pop('deep', None)
recursive = opts.pop('recursive', None)
method = opts.pop('method', 'matching')
else:
method = 'old'
def groebnersimp(ex, **opts):
def traverse(e):
if e.is_Atom:
return e
args = [traverse(x) for x in e.args]
if e.is_Function or e.is_Pow:
args = [trigsimp_groebner(x, **opts) for x in args]
return e.func(*args)
new = traverse(ex)
if not isinstance(new, Expr):
return new
return trigsimp_groebner(new, **opts)
trigsimpfunc = {
'fu': (lambda x: fu(x, **opts)),
'matching': (lambda x: futrig(x)),
'groebner': (lambda x: groebnersimp(x, **opts)),
'combined': (lambda x: futrig(groebnersimp(x,
polynomial=True, hints=[2, tan]))),
'old': lambda x: trigsimp_old(x, **opts),
}[method]
return trigsimpfunc(expr)
def exptrigsimp(expr):
"""
Simplifies exponential / trigonometric / hyperbolic functions.
Examples
========
>>> from sympy import exptrigsimp, exp, cosh, sinh
>>> from sympy.abc import z
>>> exptrigsimp(exp(z) + exp(-z))
2*cosh(z)
>>> exptrigsimp(cosh(z) - sinh(z))
exp(-z)
"""
from sympy.simplify.fu import hyper_as_trig, TR2i
from sympy.simplify.simplify import bottom_up
def exp_trig(e):
# select the better of e, and e rewritten in terms of exp or trig
# functions
choices = [e]
if e.has(*_trigs):
choices.append(e.rewrite(exp))
choices.append(e.rewrite(cos))
return min(*choices, key=count_ops)
newexpr = bottom_up(expr, exp_trig)
def f(rv):
if not rv.is_Mul:
return rv
commutative_part, noncommutative_part = rv.args_cnc()
# Since as_powers_dict loses order information,
# if there is more than one noncommutative factor,
# it should only be used to simplify the commutative part.
if (len(noncommutative_part) > 1):
return f(Mul(*commutative_part))*Mul(*noncommutative_part)
rvd = rv.as_powers_dict()
newd = rvd.copy()
def signlog(expr, sign=1):
if expr is S.Exp1:
return sign, 1
elif isinstance(expr, exp):
return sign, expr.args[0]
elif sign == 1:
return signlog(-expr, sign=-1)
else:
return None, None
ee = rvd[S.Exp1]
for k in rvd:
if k.is_Add and len(k.args) == 2:
# k == c*(1 + sign*E**x)
c = k.args[0]
sign, x = signlog(k.args[1]/c)
if not x:
continue
m = rvd[k]
newd[k] -= m
if ee == -x*m/2:
# sinh and cosh
newd[S.Exp1] -= ee
ee = 0
if sign == 1:
newd[2*c*cosh(x/2)] += m
else:
newd[-2*c*sinh(x/2)] += m
elif newd[1 - sign*S.Exp1**x] == -m:
# tanh
del newd[1 - sign*S.Exp1**x]
if sign == 1:
newd[-c/tanh(x/2)] += m
else:
newd[-c*tanh(x/2)] += m
else:
newd[1 + sign*S.Exp1**x] += m
newd[c] += m
return Mul(*[k**newd[k] for k in newd])
newexpr = bottom_up(newexpr, f)
# sin/cos and sinh/cosh ratios to tan and tanh, respectively
if newexpr.has(HyperbolicFunction):
e, f = hyper_as_trig(newexpr)
newexpr = f(TR2i(e))
if newexpr.has(TrigonometricFunction):
newexpr = TR2i(newexpr)
# can we ever generate an I where there was none previously?
if not (newexpr.has(I) and not expr.has(I)):
expr = newexpr
return expr
#-------------------- the old trigsimp routines ---------------------
def trigsimp_old(expr, **opts):
"""
reduces expression by using known trig identities
Notes
=====
deep:
- Apply trigsimp inside all objects with arguments
recursive:
- Use common subexpression elimination (cse()) and apply
trigsimp recursively (this is quite expensive if the
expression is large)
method:
- Determine the method to use. Valid choices are 'matching' (default),
'groebner', 'combined', 'fu' and 'futrig'. If 'matching', simplify the
expression recursively by pattern matching. If 'groebner', apply an
experimental groebner basis algorithm. In this case further options
are forwarded to ``trigsimp_groebner``, please refer to its docstring.
If 'combined', first run the groebner basis algorithm with small
default parameters, then run the 'matching' algorithm. 'fu' runs the
collection of trigonometric transformations described by Fu, et al.
(see the `fu` docstring) while `futrig` runs a subset of Fu-transforms
that mimic the behavior of `trigsimp`.
compare:
- show input and output from `trigsimp` and `futrig` when different,
but returns the `trigsimp` value.
Examples
========
>>> from sympy import trigsimp, sin, cos, log, cosh, sinh, tan, cot
>>> from sympy.abc import x, y
>>> e = 2*sin(x)**2 + 2*cos(x)**2
>>> trigsimp(e, old=True)
2
>>> trigsimp(log(e), old=True)
log(2*sin(x)**2 + 2*cos(x)**2)
>>> trigsimp(log(e), deep=True, old=True)
log(2)
Using `method="groebner"` (or `"combined"`) can sometimes lead to a lot
more simplification:
>>> e = (-sin(x) + 1)/cos(x) + cos(x)/(-sin(x) + 1)
>>> trigsimp(e, old=True)
(-sin(x) + 1)/cos(x) + cos(x)/(-sin(x) + 1)
>>> trigsimp(e, method="groebner", old=True)
2/cos(x)
>>> trigsimp(1/cot(x)**2, compare=True, old=True)
futrig: tan(x)**2
cot(x)**(-2)
"""
old = expr
first = opts.pop('first', True)
if first:
if not expr.has(*_trigs):
return expr
trigsyms = set().union(*[t.free_symbols for t in expr.atoms(*_trigs)])
if len(trigsyms) > 1:
d = separatevars(expr)
if d.is_Mul:
d = separatevars(d, dict=True) or d
if isinstance(d, dict):
expr = 1
for k, v in d.items():
# remove hollow factoring
was = v
v = expand_mul(v)
opts['first'] = False
vnew = trigsimp(v, **opts)
if vnew == v:
vnew = was
expr *= vnew
old = expr
else:
if d.is_Add:
for s in trigsyms:
r, e = expr.as_independent(s)
if r:
opts['first'] = False
expr = r + trigsimp(e, **opts)
if not expr.is_Add:
break
old = expr
recursive = opts.pop('recursive', False)
deep = opts.pop('deep', False)
method = opts.pop('method', 'matching')
def groebnersimp(ex, deep, **opts):
def traverse(e):
if e.is_Atom:
return e
args = [traverse(x) for x in e.args]
if e.is_Function or e.is_Pow:
args = [trigsimp_groebner(x, **opts) for x in args]
return e.func(*args)
if deep:
ex = traverse(ex)
return trigsimp_groebner(ex, **opts)
trigsimpfunc = {
'matching': (lambda x, d: _trigsimp(x, d)),
'groebner': (lambda x, d: groebnersimp(x, d, **opts)),
'combined': (lambda x, d: _trigsimp(groebnersimp(x,
d, polynomial=True, hints=[2, tan]),
d))
}[method]
if recursive:
w, g = cse(expr)
g = trigsimpfunc(g[0], deep)
for sub in reversed(w):
g = g.subs(sub[0], sub[1])
g = trigsimpfunc(g, deep)
result = g
else:
result = trigsimpfunc(expr, deep)
if opts.get('compare', False):
f = futrig(old)
if f != result:
print('\tfutrig:', f)
return result
def _dotrig(a, b):
"""Helper to tell whether ``a`` and ``b`` have the same sorts
of symbols in them -- no need to test hyperbolic patterns against
expressions that have no hyperbolics in them."""
return a.func == b.func and (
a.has(TrigonometricFunction) and b.has(TrigonometricFunction) or
a.has(HyperbolicFunction) and b.has(HyperbolicFunction))
_trigpat = None
def _trigpats():
global _trigpat
a, b, c = symbols('a b c', cls=Wild)
d = Wild('d', commutative=False)
# for the simplifications like sinh/cosh -> tanh:
# DO NOT REORDER THE FIRST 14 since these are assumed to be in this
# order in _match_div_rewrite.
matchers_division = (
(a*sin(b)**c/cos(b)**c, a*tan(b)**c, sin(b), cos(b)),
(a*tan(b)**c*cos(b)**c, a*sin(b)**c, sin(b), cos(b)),
(a*cot(b)**c*sin(b)**c, a*cos(b)**c, sin(b), cos(b)),
(a*tan(b)**c/sin(b)**c, a/cos(b)**c, sin(b), cos(b)),
(a*cot(b)**c/cos(b)**c, a/sin(b)**c, sin(b), cos(b)),
(a*cot(b)**c*tan(b)**c, a, sin(b), cos(b)),
(a*(cos(b) + 1)**c*(cos(b) - 1)**c,
a*(-sin(b)**2)**c, cos(b) + 1, cos(b) - 1),
(a*(sin(b) + 1)**c*(sin(b) - 1)**c,
a*(-cos(b)**2)**c, sin(b) + 1, sin(b) - 1),
(a*sinh(b)**c/cosh(b)**c, a*tanh(b)**c, S.One, S.One),
(a*tanh(b)**c*cosh(b)**c, a*sinh(b)**c, S.One, S.One),
(a*coth(b)**c*sinh(b)**c, a*cosh(b)**c, S.One, S.One),
(a*tanh(b)**c/sinh(b)**c, a/cosh(b)**c, S.One, S.One),
(a*coth(b)**c/cosh(b)**c, a/sinh(b)**c, S.One, S.One),
(a*coth(b)**c*tanh(b)**c, a, S.One, S.One),
(c*(tanh(a) + tanh(b))/(1 + tanh(a)*tanh(b)),
tanh(a + b)*c, S.One, S.One),
)
matchers_add = (
(c*sin(a)*cos(b) + c*cos(a)*sin(b) + d, sin(a + b)*c + d),
(c*cos(a)*cos(b) - c*sin(a)*sin(b) + d, cos(a + b)*c + d),
(c*sin(a)*cos(b) - c*cos(a)*sin(b) + d, sin(a - b)*c + d),
(c*cos(a)*cos(b) + c*sin(a)*sin(b) + d, cos(a - b)*c + d),
(c*sinh(a)*cosh(b) + c*sinh(b)*cosh(a) + d, sinh(a + b)*c + d),
(c*cosh(a)*cosh(b) + c*sinh(a)*sinh(b) + d, cosh(a + b)*c + d),
)
# for cos(x)**2 + sin(x)**2 -> 1
matchers_identity = (
(a*sin(b)**2, a - a*cos(b)**2),
(a*tan(b)**2, a*(1/cos(b))**2 - a),
(a*cot(b)**2, a*(1/sin(b))**2 - a),
(a*sin(b + c), a*(sin(b)*cos(c) + sin(c)*cos(b))),
(a*cos(b + c), a*(cos(b)*cos(c) - sin(b)*sin(c))),
(a*tan(b + c), a*((tan(b) + tan(c))/(1 - tan(b)*tan(c)))),
(a*sinh(b)**2, a*cosh(b)**2 - a),
(a*tanh(b)**2, a - a*(1/cosh(b))**2),
(a*coth(b)**2, a + a*(1/sinh(b))**2),
(a*sinh(b + c), a*(sinh(b)*cosh(c) + sinh(c)*cosh(b))),
(a*cosh(b + c), a*(cosh(b)*cosh(c) + sinh(b)*sinh(c))),
(a*tanh(b + c), a*((tanh(b) + tanh(c))/(1 + tanh(b)*tanh(c)))),
)
# Reduce any lingering artifacts, such as sin(x)**2 changing
# to 1-cos(x)**2 when sin(x)**2 was "simpler"
artifacts = (
(a - a*cos(b)**2 + c, a*sin(b)**2 + c, cos),
(a - a*(1/cos(b))**2 + c, -a*tan(b)**2 + c, cos),
(a - a*(1/sin(b))**2 + c, -a*cot(b)**2 + c, sin),
(a - a*cosh(b)**2 + c, -a*sinh(b)**2 + c, cosh),
(a - a*(1/cosh(b))**2 + c, a*tanh(b)**2 + c, cosh),
(a + a*(1/sinh(b))**2 + c, a*coth(b)**2 + c, sinh),
# same as above but with noncommutative prefactor
(a*d - a*d*cos(b)**2 + c, a*d*sin(b)**2 + c, cos),
(a*d - a*d*(1/cos(b))**2 + c, -a*d*tan(b)**2 + c, cos),
(a*d - a*d*(1/sin(b))**2 + c, -a*d*cot(b)**2 + c, sin),
(a*d - a*d*cosh(b)**2 + c, -a*d*sinh(b)**2 + c, cosh),
(a*d - a*d*(1/cosh(b))**2 + c, a*d*tanh(b)**2 + c, cosh),
(a*d + a*d*(1/sinh(b))**2 + c, a*d*coth(b)**2 + c, sinh),
)
_trigpat = (a, b, c, d, matchers_division, matchers_add,
matchers_identity, artifacts)
return _trigpat
def _replace_mul_fpowxgpow(expr, f, g, rexp, h, rexph):
"""Helper for _match_div_rewrite.
Replace f(b_)**c_*g(b_)**(rexp(c_)) with h(b)**rexph(c) if f(b_)
and g(b_) are both positive or if c_ is an integer.
"""
# assert expr.is_Mul and expr.is_commutative and f != g
fargs = defaultdict(int)
gargs = defaultdict(int)
args = []
for x in expr.args:
if x.is_Pow or x.func in (f, g):
b, e = x.as_base_exp()
if b.is_positive or e.is_integer:
if b.func == f:
fargs[b.args[0]] += e
continue
elif b.func == g:
gargs[b.args[0]] += e
continue
args.append(x)
common = set(fargs) & set(gargs)
hit = False
while common:
key = common.pop()
fe = fargs.pop(key)
ge = gargs.pop(key)
if fe == rexp(ge):
args.append(h(key)**rexph(fe))
hit = True
else:
fargs[key] = fe
gargs[key] = ge
if not hit:
return expr
while fargs:
key, e = fargs.popitem()
args.append(f(key)**e)
while gargs:
key, e = gargs.popitem()
args.append(g(key)**e)
return Mul(*args)
_idn = lambda x: x
_midn = lambda x: -x
_one = lambda x: S.One
def _match_div_rewrite(expr, i):
"""helper for __trigsimp"""
if i == 0:
expr = _replace_mul_fpowxgpow(expr, sin, cos,
_midn, tan, _idn)
elif i == 1:
expr = _replace_mul_fpowxgpow(expr, tan, cos,
_idn, sin, _idn)
elif i == 2:
expr = _replace_mul_fpowxgpow(expr, cot, sin,
_idn, cos, _idn)
elif i == 3:
expr = _replace_mul_fpowxgpow(expr, tan, sin,
_midn, cos, _midn)
elif i == 4:
expr = _replace_mul_fpowxgpow(expr, cot, cos,
_midn, sin, _midn)
elif i == 5:
expr = _replace_mul_fpowxgpow(expr, cot, tan,
_idn, _one, _idn)
# i in (6, 7) is skipped
elif i == 8:
expr = _replace_mul_fpowxgpow(expr, sinh, cosh,
_midn, tanh, _idn)
elif i == 9:
expr = _replace_mul_fpowxgpow(expr, tanh, cosh,
_idn, sinh, _idn)
elif i == 10:
expr = _replace_mul_fpowxgpow(expr, coth, sinh,
_idn, cosh, _idn)
elif i == 11:
expr = _replace_mul_fpowxgpow(expr, tanh, sinh,
_midn, cosh, _midn)
elif i == 12:
expr = _replace_mul_fpowxgpow(expr, coth, cosh,
_midn, sinh, _midn)
elif i == 13:
expr = _replace_mul_fpowxgpow(expr, coth, tanh,
_idn, _one, _idn)
else:
return None
return expr
def _trigsimp(expr, deep=False):
# protect the cache from non-trig patterns; we only allow
# trig patterns to enter the cache
if expr.has(*_trigs):
return __trigsimp(expr, deep)
return expr
@cacheit
def __trigsimp(expr, deep=False):
"""recursive helper for trigsimp"""
from sympy.simplify.fu import TR10i
if _trigpat is None:
_trigpats()
a, b, c, d, matchers_division, matchers_add, \
matchers_identity, artifacts = _trigpat
if expr.is_Mul:
# do some simplifications like sin/cos -> tan:
if not expr.is_commutative:
com, nc = expr.args_cnc()
expr = _trigsimp(Mul._from_args(com), deep)*Mul._from_args(nc)
else:
for i, (pattern, simp, ok1, ok2) in enumerate(matchers_division):
if not _dotrig(expr, pattern):
continue
newexpr = _match_div_rewrite(expr, i)
if newexpr is not None:
if newexpr != expr:
expr = newexpr
break
else:
continue
# use SymPy matching instead
res = expr.match(pattern)
if res and res.get(c, 0):
if not res[c].is_integer:
ok = ok1.subs(res)
if not ok.is_positive:
continue
ok = ok2.subs(res)
if not ok.is_positive:
continue
# if "a" contains any of trig or hyperbolic funcs with
# argument "b" then skip the simplification
if any(w.args[0] == res[b] for w in res[a].atoms(
TrigonometricFunction, HyperbolicFunction)):
continue
# simplify and finish:
expr = simp.subs(res)
break # process below
if expr.is_Add:
args = []
for term in expr.args:
if not term.is_commutative:
com, nc = term.args_cnc()
nc = Mul._from_args(nc)
term = Mul._from_args(com)
else:
nc = S.One
term = _trigsimp(term, deep)
for pattern, result in matchers_identity:
res = term.match(pattern)
if res is not None:
term = result.subs(res)
break
args.append(term*nc)
if args != expr.args:
expr = Add(*args)
expr = min(expr, expand(expr), key=count_ops)
if expr.is_Add:
for pattern, result in matchers_add:
if not _dotrig(expr, pattern):
continue
expr = TR10i(expr)
if expr.has(HyperbolicFunction):
res = expr.match(pattern)
# if "d" contains any trig or hyperbolic funcs with
# argument "a" or "b" then skip the simplification;
# this isn't perfect -- see tests
if res is None or not (a in res and b in res) or any(
w.args[0] in (res[a], res[b]) for w in res[d].atoms(
TrigonometricFunction, HyperbolicFunction)):
continue
expr = result.subs(res)
break
# Reduce any lingering artifacts, such as sin(x)**2 changing
# to 1 - cos(x)**2 when sin(x)**2 was "simpler"
for pattern, result, ex in artifacts:
if not _dotrig(expr, pattern):
continue
# Substitute a new wild that excludes some function(s)
# to help influence a better match. This is because
# sometimes, for example, 'a' would match sec(x)**2
a_t = Wild('a', exclude=[ex])
pattern = pattern.subs(a, a_t)
result = result.subs(a, a_t)
m = expr.match(pattern)
was = None
while m and was != expr:
was = expr
if m[a_t] == 0 or \
-m[a_t] in m[c].args or m[a_t] + m[c] == 0:
break
if d in m and m[a_t]*m[d] + m[c] == 0:
break
expr = result.subs(m)
m = expr.match(pattern)
m.setdefault(c, S.Zero)
elif expr.is_Mul or expr.is_Pow or deep and expr.args:
expr = expr.func(*[_trigsimp(a, deep) for a in expr.args])
try:
if not expr.has(*_trigs):
raise TypeError
e = expr.atoms(exp)
new = expr.rewrite(exp, deep=deep)
if new == e:
raise TypeError
fnew = factor(new)
if fnew != new:
new = sorted([new, factor(new)], key=count_ops)[0]
# if all exp that were introduced disappeared then accept it
if not (new.atoms(exp) - e):
expr = new
except TypeError:
pass
return expr
#------------------- end of old trigsimp routines --------------------
def futrig(e, **kwargs):
"""Return simplified ``e`` using Fu-like transformations.
This is not the "Fu" algorithm. This is called by default
from ``trigsimp``. By default, hyperbolics subexpressions
will be simplified, but this can be disabled by setting
``hyper=False``.
Examples
========
>>> from sympy import trigsimp, tan, sinh, tanh
>>> from sympy.simplify.trigsimp import futrig
>>> from sympy.abc import x
>>> trigsimp(1/tan(x)**2)
tan(x)**(-2)
>>> futrig(sinh(x)/tanh(x))
cosh(x)
"""
from sympy.simplify.fu import hyper_as_trig
from sympy.simplify.simplify import bottom_up
e = sympify(e)
if not isinstance(e, Basic):
return e
if not e.args:
return e
old = e
e = bottom_up(e, lambda x: _futrig(x, **kwargs))
if kwargs.pop('hyper', True) and e.has(HyperbolicFunction):
e, f = hyper_as_trig(e)
e = f(_futrig(e))
if e != old and e.is_Mul and e.args[0].is_Rational:
# redistribute leading coeff on 2-arg Add
e = Mul(*e.as_coeff_Mul())
return e
def _futrig(e, **kwargs):
"""Helper for futrig."""
from sympy.simplify.fu import (
TR1, TR2, TR3, TR2i, TR10, L, TR10i,
TR8, TR6, TR15, TR16, TR111, TR5, TRmorrie, TR11, TR14, TR22,
TR12)
from sympy.core.compatibility import _nodes
if not e.has(TrigonometricFunction):
return e
if e.is_Mul:
coeff, e = e.as_independent(TrigonometricFunction)
else:
coeff = S.One
Lops = lambda x: (L(x), x.count_ops(), _nodes(x), len(x.args), x.is_Add)
trigs = lambda x: x.has(TrigonometricFunction)
tree = [identity,
(
TR3, # canonical angles
TR1, # sec-csc -> cos-sin
TR12, # expand tan of sum
lambda x: _eapply(factor, x, trigs),
TR2, # tan-cot -> sin-cos
[identity, lambda x: _eapply(_mexpand, x, trigs)],
TR2i, # sin-cos ratio -> tan
lambda x: _eapply(lambda i: factor(i.normal()), x, trigs),
TR14, # factored identities
TR5, # sin-pow -> cos_pow
TR10, # sin-cos of sums -> sin-cos prod
TR11, TR6, # reduce double angles and rewrite cos pows
lambda x: _eapply(factor, x, trigs),
TR14, # factored powers of identities
[identity, lambda x: _eapply(_mexpand, x, trigs)],
TR10i, # sin-cos products > sin-cos of sums
TRmorrie,
[identity, TR8], # sin-cos products -> sin-cos of sums
[identity, lambda x: TR2i(TR2(x))], # tan -> sin-cos -> tan
[
lambda x: _eapply(expand_mul, TR5(x), trigs),
lambda x: _eapply(
expand_mul, TR15(x), trigs)], # pos/neg powers of sin
[
lambda x: _eapply(expand_mul, TR6(x), trigs),
lambda x: _eapply(
expand_mul, TR16(x), trigs)], # pos/neg powers of cos
TR111, # tan, sin, cos to neg power -> cot, csc, sec
[identity, TR2i], # sin-cos ratio to tan
[identity, lambda x: _eapply(
expand_mul, TR22(x), trigs)], # tan-cot to sec-csc
TR1, TR2, TR2i,
[identity, lambda x: _eapply(
factor_terms, TR12(x), trigs)], # expand tan of sum
)]
e = greedy(tree, objective=Lops)(e)
return coeff*e
def _is_Expr(e):
"""_eapply helper to tell whether ``e`` and all its args
are Exprs."""
from sympy import Derivative
if isinstance(e, Derivative):
return _is_Expr(e.expr)
if not isinstance(e, Expr):
return False
return all(_is_Expr(i) for i in e.args)
def _eapply(func, e, cond=None):
"""Apply ``func`` to ``e`` if all args are Exprs else only
apply it to those args that *are* Exprs."""
if not isinstance(e, Expr):
return e
if _is_Expr(e) or not e.args:
return func(e)
return e.func(*[
_eapply(func, ei) if (cond is None or cond(ei)) else ei
for ei in e.args])
|
4796d9b768ef8039047323447eb0714752145f5e7afe183229f0f36bca248970
|
r"""
This module contains the functionality to arrange the nodes of a
diagram on an abstract grid, and then to produce a graphical
representation of the grid.
The currently supported back-ends are Xy-pic [Xypic].
Layout Algorithm
================
This section provides an overview of the algorithms implemented in
:class:`DiagramGrid` to lay out diagrams.
The first step of the algorithm is the removal composite and identity
morphisms which do not have properties in the supplied diagram. The
premises and conclusions of the diagram are then merged.
The generic layout algorithm begins with the construction of the
"skeleton" of the diagram. The skeleton is an undirected graph which
has the objects of the diagram as vertices and has an (undirected)
edge between each pair of objects between which there exist morphisms.
The direction of the morphisms does not matter at this stage. The
skeleton also includes an edge between each pair of vertices `A` and
`C` such that there exists an object `B` which is connected via
a morphism to `A`, and via a morphism to `C`.
The skeleton constructed in this way has the property that every
object is a vertex of a triangle formed by three edges of the
skeleton. This property lies at the base of the generic layout
algorithm.
After the skeleton has been constructed, the algorithm lists all
triangles which can be formed. Note that some triangles will not have
all edges corresponding to morphisms which will actually be drawn.
Triangles which have only one edge or less which will actually be
drawn are immediately discarded.
The list of triangles is sorted according to the number of edges which
correspond to morphisms, then the triangle with the least number of such
edges is selected. One of such edges is picked and the corresponding
objects are placed horizontally, on a grid. This edge is recorded to
be in the fringe. The algorithm then finds a "welding" of a triangle
to the fringe. A welding is an edge in the fringe where a triangle
could be attached. If the algorithm succeeds in finding such a
welding, it adds to the grid that vertex of the triangle which was not
yet included in any edge in the fringe and records the two new edges in
the fringe. This process continues iteratively until all objects of
the diagram has been placed or until no more weldings can be found.
An edge is only removed from the fringe when a welding to this edge
has been found, and there is no room around this edge to place
another vertex.
When no more weldings can be found, but there are still triangles
left, the algorithm searches for a possibility of attaching one of the
remaining triangles to the existing structure by a vertex. If such a
possibility is found, the corresponding edge of the found triangle is
placed in the found space and the iterative process of welding
triangles restarts.
When logical groups are supplied, each of these groups is laid out
independently. Then a diagram is constructed in which groups are
objects and any two logical groups between which there exist morphisms
are connected via a morphism. This diagram is laid out. Finally,
the grid which includes all objects of the initial diagram is
constructed by replacing the cells which contain logical groups with
the corresponding laid out grids, and by correspondingly expanding the
rows and columns.
The sequential layout algorithm begins by constructing the
underlying undirected graph defined by the morphisms obtained after
simplifying premises and conclusions and merging them (see above).
The vertex with the minimal degree is then picked up and depth-first
search is started from it. All objects which are located at distance
`n` from the root in the depth-first search tree, are positioned in
the `n`-th column of the resulting grid. The sequential layout will
therefore attempt to lay the objects out along a line.
References
==========
[Xypic] http://xy-pic.sourceforge.net/
"""
from __future__ import print_function, division
from sympy.core import Dict, Symbol
from sympy.sets import FiniteSet
from sympy.categories import (CompositeMorphism, IdentityMorphism,
NamedMorphism, Diagram)
from sympy.utilities import default_sort_key
from itertools import chain
from sympy.core.compatibility import iterable, range
from sympy.printing import latex
from sympy.utilities.decorator import doctest_depends_on
__doctest_requires__ = {('preview_diagram',): 'pyglet'}
class _GrowableGrid(object):
"""
Holds a growable grid of objects.
It is possible to append or prepend a row or a column to the grid
using the corresponding methods. Prepending rows or columns has
the effect of changing the coordinates of the already existing
elements.
This class currently represents a naive implementation of the
functionality with little attempt at optimisation.
"""
def __init__(self, width, height):
self._width = width
self._height = height
self._array = [[None for j in range(width)] for i in range(height)]
@property
def width(self):
return self._width
@property
def height(self):
return self._height
def __getitem__(self, i_j):
"""
Returns the element located at in the i-th line and j-th
column.
"""
i, j = i_j
return self._array[i][j]
def __setitem__(self, i_j, newvalue):
"""
Sets the element located at in the i-th line and j-th
column.
"""
i, j = i_j
self._array[i][j] = newvalue
def append_row(self):
"""
Appends an empty row to the grid.
"""
self._height += 1
self._array.append([None for j in range(self._width)])
def append_column(self):
"""
Appends an empty column to the grid.
"""
self._width += 1
for i in range(self._height):
self._array[i].append(None)
def prepend_row(self):
"""
Prepends the grid with an empty row.
"""
self._height += 1
self._array.insert(0, [None for j in range(self._width)])
def prepend_column(self):
"""
Prepends the grid with an empty column.
"""
self._width += 1
for i in range(self._height):
self._array[i].insert(0, None)
class DiagramGrid(object):
r"""
Constructs and holds the fitting of the diagram into a grid.
The mission of this class is to analyse the structure of the
supplied diagram and to place its objects on a grid such that,
when the objects and the morphisms are actually drawn, the diagram
would be "readable", in the sense that there will not be many
intersections of moprhisms. This class does not perform any
actual drawing. It does strive nevertheless to offer sufficient
metadata to draw a diagram.
Consider the following simple diagram.
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> from sympy import pprint
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
The simplest way to have a diagram laid out is the following:
>>> grid = DiagramGrid(diagram)
>>> (grid.width, grid.height)
(2, 2)
>>> pprint(grid)
A B
<BLANKLINE>
C
Sometimes one sees the diagram as consisting of logical groups.
One can advise ``DiagramGrid`` as to such groups by employing the
``groups`` keyword argument.
Consider the following diagram:
>>> D = Object("D")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> h = NamedMorphism(D, A, "h")
>>> k = NamedMorphism(D, B, "k")
>>> diagram = Diagram([f, g, h, k])
Lay it out with generic layout:
>>> grid = DiagramGrid(diagram)
>>> pprint(grid)
A B D
<BLANKLINE>
C
Now, we can group the objects `A` and `D` to have them near one
another:
>>> grid = DiagramGrid(diagram, groups=[[A, D], B, C])
>>> pprint(grid)
B C
<BLANKLINE>
A D
Note how the positioning of the other objects changes.
Further indications can be supplied to the constructor of
:class:`DiagramGrid` using keyword arguments. The currently
supported hints are explained in the following paragraphs.
:class:`DiagramGrid` does not automatically guess which layout
would suit the supplied diagram better. Consider, for example,
the following linear diagram:
>>> E = Object("E")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> h = NamedMorphism(C, D, "h")
>>> i = NamedMorphism(D, E, "i")
>>> diagram = Diagram([f, g, h, i])
When laid out with the generic layout, it does not get to look
linear:
>>> grid = DiagramGrid(diagram)
>>> pprint(grid)
A B
<BLANKLINE>
C D
<BLANKLINE>
E
To get it laid out in a line, use ``layout="sequential"``:
>>> grid = DiagramGrid(diagram, layout="sequential")
>>> pprint(grid)
A B C D E
One may sometimes need to transpose the resulting layout. While
this can always be done by hand, :class:`DiagramGrid` provides a
hint for that purpose:
>>> grid = DiagramGrid(diagram, layout="sequential", transpose=True)
>>> pprint(grid)
A
<BLANKLINE>
B
<BLANKLINE>
C
<BLANKLINE>
D
<BLANKLINE>
E
Separate hints can also be provided for each group. For an
example, refer to ``tests/test_drawing.py``, and see the different
ways in which the five lemma [FiveLemma] can be laid out.
See Also
========
Diagram
References
==========
[FiveLemma] https://en.wikipedia.org/wiki/Five_lemma
"""
@staticmethod
def _simplify_morphisms(morphisms):
"""
Given a dictionary mapping morphisms to their properties,
returns a new dictionary in which there are no morphisms which
do not have properties, and which are compositions of other
morphisms included in the dictionary. Identities are dropped
as well.
"""
newmorphisms = {}
for morphism, props in morphisms.items():
if isinstance(morphism, CompositeMorphism) and not props:
continue
elif isinstance(morphism, IdentityMorphism):
continue
else:
newmorphisms[morphism] = props
return newmorphisms
@staticmethod
def _merge_premises_conclusions(premises, conclusions):
"""
Given two dictionaries of morphisms and their properties,
produces a single dictionary which includes elements from both
dictionaries. If a morphism has some properties in premises
and also in conclusions, the properties in conclusions take
priority.
"""
return dict(chain(premises.items(), conclusions.items()))
@staticmethod
def _juxtapose_edges(edge1, edge2):
"""
If ``edge1`` and ``edge2`` have precisely one common endpoint,
returns an edge which would form a triangle with ``edge1`` and
``edge2``.
If ``edge1`` and ``edge2`` don't have a common endpoint,
returns ``None``.
If ``edge1`` and ``edge`` are the same edge, returns ``None``.
"""
intersection = edge1 & edge2
if len(intersection) != 1:
# The edges either have no common points or are equal.
return None
# The edges have a common endpoint. Extract the different
# endpoints and set up the new edge.
return (edge1 - intersection) | (edge2 - intersection)
@staticmethod
def _add_edge_append(dictionary, edge, elem):
"""
If ``edge`` is not in ``dictionary``, adds ``edge`` to the
dictionary and sets its value to ``[elem]``. Otherwise
appends ``elem`` to the value of existing entry.
Note that edges are undirected, thus `(A, B) = (B, A)`.
"""
if edge in dictionary:
dictionary[edge].append(elem)
else:
dictionary[edge] = [elem]
@staticmethod
def _build_skeleton(morphisms):
"""
Creates a dictionary which maps edges to corresponding
morphisms. Thus for a morphism `f:A\rightarrow B`, the edge
`(A, B)` will be associated with `f`. This function also adds
to the list those edges which are formed by juxtaposition of
two edges already in the list. These new edges are not
associated with any morphism and are only added to assure that
the diagram can be decomposed into triangles.
"""
edges = {}
# Create edges for morphisms.
for morphism in morphisms:
DiagramGrid._add_edge_append(
edges, frozenset([morphism.domain, morphism.codomain]), morphism)
# Create new edges by juxtaposing existing edges.
edges1 = dict(edges)
for w in edges1:
for v in edges1:
wv = DiagramGrid._juxtapose_edges(w, v)
if wv and wv not in edges:
edges[wv] = []
return edges
@staticmethod
def _list_triangles(edges):
"""
Builds the set of triangles formed by the supplied edges. The
triangles are arbitrary and need not be commutative. A
triangle is a set that contains all three of its sides.
"""
triangles = set()
for w in edges:
for v in edges:
wv = DiagramGrid._juxtapose_edges(w, v)
if wv and wv in edges:
triangles.add(frozenset([w, v, wv]))
return triangles
@staticmethod
def _drop_redundant_triangles(triangles, skeleton):
"""
Returns a list which contains only those triangles who have
morphisms associated with at least two edges.
"""
return [tri for tri in triangles
if len([e for e in tri if skeleton[e]]) >= 2]
@staticmethod
def _morphism_length(morphism):
"""
Returns the length of a morphism. The length of a morphism is
the number of components it consists of. A non-composite
morphism is of length 1.
"""
if isinstance(morphism, CompositeMorphism):
return len(morphism.components)
else:
return 1
@staticmethod
def _compute_triangle_min_sizes(triangles, edges):
r"""
Returns a dictionary mapping triangles to their minimal sizes.
The minimal size of a triangle is the sum of maximal lengths
of morphisms associated to the sides of the triangle. The
length of a morphism is the number of components it consists
of. A non-composite morphism is of length 1.
Sorting triangles by this metric attempts to address two
aspects of layout. For triangles with only simple morphisms
in the edge, this assures that triangles with all three edges
visible will get typeset after triangles with less visible
edges, which sometimes minimizes the necessity in diagonal
arrows. For triangles with composite morphisms in the edges,
this assures that objects connected with shorter morphisms
will be laid out first, resulting the visual proximity of
those objects which are connected by shorter morphisms.
"""
triangle_sizes = {}
for triangle in triangles:
size = 0
for e in triangle:
morphisms = edges[e]
if morphisms:
size += max(DiagramGrid._morphism_length(m)
for m in morphisms)
triangle_sizes[triangle] = size
return triangle_sizes
@staticmethod
def _triangle_objects(triangle):
"""
Given a triangle, returns the objects included in it.
"""
# A triangle is a frozenset of three two-element frozensets
# (the edges). This chains the three edges together and
# creates a frozenset from the iterator, thus producing a
# frozenset of objects of the triangle.
return frozenset(chain(*tuple(triangle)))
@staticmethod
def _other_vertex(triangle, edge):
"""
Given a triangle and an edge of it, returns the vertex which
opposes the edge.
"""
# This gets the set of objects of the triangle and then
# subtracts the set of objects employed in ``edge`` to get the
# vertex opposite to ``edge``.
return list(DiagramGrid._triangle_objects(triangle) - set(edge))[0]
@staticmethod
def _empty_point(pt, grid):
"""
Checks if the cell at coordinates ``pt`` is either empty or
out of the bounds of the grid.
"""
if (pt[0] < 0) or (pt[1] < 0) or \
(pt[0] >= grid.height) or (pt[1] >= grid.width):
return True
return grid[pt] is None
@staticmethod
def _put_object(coords, obj, grid, fringe):
"""
Places an object at the coordinate ``cords`` in ``grid``,
growing the grid and updating ``fringe``, if necessary.
Returns (0, 0) if no row or column has been prepended, (1, 0)
if a row was prepended, (0, 1) if a column was prepended and
(1, 1) if both a column and a row were prepended.
"""
(i, j) = coords
offset = (0, 0)
if i == -1:
grid.prepend_row()
i = 0
offset = (1, 0)
for k in range(len(fringe)):
((i1, j1), (i2, j2)) = fringe[k]
fringe[k] = ((i1 + 1, j1), (i2 + 1, j2))
elif i == grid.height:
grid.append_row()
if j == -1:
j = 0
offset = (offset[0], 1)
grid.prepend_column()
for k in range(len(fringe)):
((i1, j1), (i2, j2)) = fringe[k]
fringe[k] = ((i1, j1 + 1), (i2, j2 + 1))
elif j == grid.width:
grid.append_column()
grid[i, j] = obj
return offset
@staticmethod
def _choose_target_cell(pt1, pt2, edge, obj, skeleton, grid):
"""
Given two points, ``pt1`` and ``pt2``, and the welding edge
``edge``, chooses one of the two points to place the opposing
vertex ``obj`` of the triangle. If neither of this points
fits, returns ``None``.
"""
pt1_empty = DiagramGrid._empty_point(pt1, grid)
pt2_empty = DiagramGrid._empty_point(pt2, grid)
if pt1_empty and pt2_empty:
# Both cells are empty. Of these two, choose that cell
# which will assure that a visible edge of the triangle
# will be drawn perpendicularly to the current welding
# edge.
A = grid[edge[0]]
B = grid[edge[1]]
if skeleton.get(frozenset([A, obj])):
return pt1
else:
return pt2
if pt1_empty:
return pt1
elif pt2_empty:
return pt2
else:
return None
@staticmethod
def _find_triangle_to_weld(triangles, fringe, grid):
"""
Finds, if possible, a triangle and an edge in the fringe to
which the triangle could be attached. Returns the tuple
containing the triangle and the index of the corresponding
edge in the fringe.
This function relies on the fact that objects are unique in
the diagram.
"""
for triangle in triangles:
for (a, b) in fringe:
if frozenset([grid[a], grid[b]]) in triangle:
return (triangle, (a, b))
return None
@staticmethod
def _weld_triangle(tri, welding_edge, fringe, grid, skeleton):
"""
If possible, welds the triangle ``tri`` to ``fringe`` and
returns ``False``. If this method encounters a degenerate
situation in the fringe and corrects it such that a restart of
the search is required, it returns ``True`` (which means that
a restart in finding triangle weldings is required).
A degenerate situation is a situation when an edge listed in
the fringe does not belong to the visual boundary of the
diagram.
"""
a, b = welding_edge
target_cell = None
obj = DiagramGrid._other_vertex(tri, (grid[a], grid[b]))
# We now have a triangle and an edge where it can be welded to
# the fringe. Decide where to place the other vertex of the
# triangle and check for degenerate situations en route.
if (abs(a[0] - b[0]) == 1) and (abs(a[1] - b[1]) == 1):
# A diagonal edge.
target_cell = (a[0], b[1])
if grid[target_cell]:
# That cell is already occupied.
target_cell = (b[0], a[1])
if grid[target_cell]:
# Degenerate situation, this edge is not
# on the actual fringe. Correct the
# fringe and go on.
fringe.remove((a, b))
return True
elif a[0] == b[0]:
# A horizontal edge. We first attempt to build the
# triangle in the downward direction.
down_left = a[0] + 1, a[1]
down_right = a[0] + 1, b[1]
target_cell = DiagramGrid._choose_target_cell(
down_left, down_right, (a, b), obj, skeleton, grid)
if not target_cell:
# No room below this edge. Check above.
up_left = a[0] - 1, a[1]
up_right = a[0] - 1, b[1]
target_cell = DiagramGrid._choose_target_cell(
up_left, up_right, (a, b), obj, skeleton, grid)
if not target_cell:
# This edge is not in the fringe, remove it
# and restart.
fringe.remove((a, b))
return True
elif a[1] == b[1]:
# A vertical edge. We will attempt to place the other
# vertex of the triangle to the right of this edge.
right_up = a[0], a[1] + 1
right_down = b[0], a[1] + 1
target_cell = DiagramGrid._choose_target_cell(
right_up, right_down, (a, b), obj, skeleton, grid)
if not target_cell:
# No room to the left. See what's to the right.
left_up = a[0], a[1] - 1
left_down = b[0], a[1] - 1
target_cell = DiagramGrid._choose_target_cell(
left_up, left_down, (a, b), obj, skeleton, grid)
if not target_cell:
# This edge is not in the fringe, remove it
# and restart.
fringe.remove((a, b))
return True
# We now know where to place the other vertex of the
# triangle.
offset = DiagramGrid._put_object(target_cell, obj, grid, fringe)
# Take care of the displacement of coordinates if a row or
# a column was prepended.
target_cell = (target_cell[0] + offset[0],
target_cell[1] + offset[1])
a = (a[0] + offset[0], a[1] + offset[1])
b = (b[0] + offset[0], b[1] + offset[1])
fringe.extend([(a, target_cell), (b, target_cell)])
# No restart is required.
return False
@staticmethod
def _triangle_key(tri, triangle_sizes):
"""
Returns a key for the supplied triangle. It should be the
same independently of the hash randomisation.
"""
objects = sorted(
DiagramGrid._triangle_objects(tri), key=default_sort_key)
return (triangle_sizes[tri], default_sort_key(objects))
@staticmethod
def _pick_root_edge(tri, skeleton):
"""
For a given triangle always picks the same root edge. The
root edge is the edge that will be placed first on the grid.
"""
candidates = [sorted(e, key=default_sort_key)
for e in tri if skeleton[e]]
sorted_candidates = sorted(candidates, key=default_sort_key)
# Don't forget to assure the proper ordering of the vertices
# in this edge.
return tuple(sorted(sorted_candidates[0], key=default_sort_key))
@staticmethod
def _drop_irrelevant_triangles(triangles, placed_objects):
"""
Returns only those triangles whose set of objects is not
completely included in ``placed_objects``.
"""
return [tri for tri in triangles if not placed_objects.issuperset(
DiagramGrid._triangle_objects(tri))]
@staticmethod
def _grow_pseudopod(triangles, fringe, grid, skeleton, placed_objects):
"""
Starting from an object in the existing structure on the grid,
adds an edge to which a triangle from ``triangles`` could be
welded. If this method has found a way to do so, it returns
the object it has just added.
This method should be applied when ``_weld_triangle`` cannot
find weldings any more.
"""
for i in range(grid.height):
for j in range(grid.width):
obj = grid[i, j]
if not obj:
continue
# Here we need to choose a triangle which has only
# ``obj`` in common with the existing structure. The
# situations when this is not possible should be
# handled elsewhere.
def good_triangle(tri):
objs = DiagramGrid._triangle_objects(tri)
return obj in objs and \
placed_objects & (objs - {obj}) == set()
tris = [tri for tri in triangles if good_triangle(tri)]
if not tris:
# This object is not interesting.
continue
# Pick the "simplest" of the triangles which could be
# attached. Remember that the list of triangles is
# sorted according to their "simplicity" (see
# _compute_triangle_min_sizes for the metric).
#
# Note that ``tris`` are sequentially built from
# ``triangles``, so we don't have to worry about hash
# randomisation.
tri = tris[0]
# We have found a triangle which could be attached to
# the existing structure by a vertex.
candidates = sorted([e for e in tri if skeleton[e]],
key=lambda e: FiniteSet(*e).sort_key())
edges = [e for e in candidates if obj in e]
# Note that a meaningful edge (i.e., and edge that is
# associated with a morphism) containing ``obj``
# always exists. That's because all triangles are
# guaranteed to have at least two meaningful edges.
# See _drop_redundant_triangles.
# Get the object at the other end of the edge.
edge = edges[0]
other_obj = tuple(edge - frozenset([obj]))[0]
# Now check for free directions. When checking for
# free directions, prefer the horizontal and vertical
# directions.
neighbours = [(i - 1, j), (i, j + 1), (i + 1, j), (i, j - 1),
(i - 1, j - 1), (i - 1, j + 1), (i + 1, j - 1), (i + 1, j + 1)]
for pt in neighbours:
if DiagramGrid._empty_point(pt, grid):
# We have a found a place to grow the
# pseudopod into.
offset = DiagramGrid._put_object(
pt, other_obj, grid, fringe)
i += offset[0]
j += offset[1]
pt = (pt[0] + offset[0], pt[1] + offset[1])
fringe.append(((i, j), pt))
return other_obj
# This diagram is actually cooler that I can handle. Fail cowardly.
return None
@staticmethod
def _handle_groups(diagram, groups, merged_morphisms, hints):
"""
Given the slightly preprocessed morphisms of the diagram,
produces a grid laid out according to ``groups``.
If a group has hints, it is laid out with those hints only,
without any influence from ``hints``. Otherwise, it is laid
out with ``hints``.
"""
def lay_out_group(group, local_hints):
"""
If ``group`` is a set of objects, uses a ``DiagramGrid``
to lay it out and returns the grid. Otherwise returns the
object (i.e., ``group``). If ``local_hints`` is not
empty, it is supplied to ``DiagramGrid`` as the dictionary
of hints. Otherwise, the ``hints`` argument of
``_handle_groups`` is used.
"""
if isinstance(group, FiniteSet):
# Set up the corresponding object-to-group
# mappings.
for obj in group:
obj_groups[obj] = group
# Lay out the current group.
if local_hints:
groups_grids[group] = DiagramGrid(
diagram.subdiagram_from_objects(group), **local_hints)
else:
groups_grids[group] = DiagramGrid(
diagram.subdiagram_from_objects(group), **hints)
else:
obj_groups[group] = group
def group_to_finiteset(group):
"""
Converts ``group`` to a :class:``FiniteSet`` if it is an
iterable.
"""
if iterable(group):
return FiniteSet(*group)
else:
return group
obj_groups = {}
groups_grids = {}
# We would like to support various containers to represent
# groups. To achieve that, before laying each group out, it
# should be converted to a FiniteSet, because that is what the
# following code expects.
if isinstance(groups, dict) or isinstance(groups, Dict):
finiteset_groups = {}
for group, local_hints in groups.items():
finiteset_group = group_to_finiteset(group)
finiteset_groups[finiteset_group] = local_hints
lay_out_group(group, local_hints)
groups = finiteset_groups
else:
finiteset_groups = []
for group in groups:
finiteset_group = group_to_finiteset(group)
finiteset_groups.append(finiteset_group)
lay_out_group(finiteset_group, None)
groups = finiteset_groups
new_morphisms = []
for morphism in merged_morphisms:
dom = obj_groups[morphism.domain]
cod = obj_groups[morphism.codomain]
# Note that we are not really interested in morphisms
# which do not employ two different groups, because
# these do not influence the layout.
if dom != cod:
# These are essentially unnamed morphisms; they are
# not going to mess in the final layout. By giving
# them the same names, we avoid unnecessary
# duplicates.
new_morphisms.append(NamedMorphism(dom, cod, "dummy"))
# Lay out the new diagram. Since these are dummy morphisms,
# properties and conclusions are irrelevant.
top_grid = DiagramGrid(Diagram(new_morphisms))
# We now have to substitute the groups with the corresponding
# grids, laid out at the beginning of this function. Compute
# the size of each row and column in the grid, so that all
# nested grids fit.
def group_size(group):
"""
For the supplied group (or object, eventually), returns
the size of the cell that will hold this group (object).
"""
if group in groups_grids:
grid = groups_grids[group]
return (grid.height, grid.width)
else:
return (1, 1)
row_heights = [max(group_size(top_grid[i, j])[0]
for j in range(top_grid.width))
for i in range(top_grid.height)]
column_widths = [max(group_size(top_grid[i, j])[1]
for i in range(top_grid.height))
for j in range(top_grid.width)]
grid = _GrowableGrid(sum(column_widths), sum(row_heights))
real_row = 0
real_column = 0
for logical_row in range(top_grid.height):
for logical_column in range(top_grid.width):
obj = top_grid[logical_row, logical_column]
if obj in groups_grids:
# This is a group. Copy the corresponding grid in
# place.
local_grid = groups_grids[obj]
for i in range(local_grid.height):
for j in range(local_grid.width):
grid[real_row + i,
real_column + j] = local_grid[i, j]
else:
# This is an object. Just put it there.
grid[real_row, real_column] = obj
real_column += column_widths[logical_column]
real_column = 0
real_row += row_heights[logical_row]
return grid
@staticmethod
def _generic_layout(diagram, merged_morphisms):
"""
Produces the generic layout for the supplied diagram.
"""
all_objects = set(diagram.objects)
if len(all_objects) == 1:
# There only one object in the diagram, just put in on 1x1
# grid.
grid = _GrowableGrid(1, 1)
grid[0, 0] = tuple(all_objects)[0]
return grid
skeleton = DiagramGrid._build_skeleton(merged_morphisms)
grid = _GrowableGrid(2, 1)
if len(skeleton) == 1:
# This diagram contains only one morphism. Draw it
# horizontally.
objects = sorted(all_objects, key=default_sort_key)
grid[0, 0] = objects[0]
grid[0, 1] = objects[1]
return grid
triangles = DiagramGrid._list_triangles(skeleton)
triangles = DiagramGrid._drop_redundant_triangles(triangles, skeleton)
triangle_sizes = DiagramGrid._compute_triangle_min_sizes(
triangles, skeleton)
triangles = sorted(triangles, key=lambda tri:
DiagramGrid._triangle_key(tri, triangle_sizes))
# Place the first edge on the grid.
root_edge = DiagramGrid._pick_root_edge(triangles[0], skeleton)
grid[0, 0], grid[0, 1] = root_edge
fringe = [((0, 0), (0, 1))]
# Record which objects we now have on the grid.
placed_objects = set(root_edge)
while placed_objects != all_objects:
welding = DiagramGrid._find_triangle_to_weld(
triangles, fringe, grid)
if welding:
(triangle, welding_edge) = welding
restart_required = DiagramGrid._weld_triangle(
triangle, welding_edge, fringe, grid, skeleton)
if restart_required:
continue
placed_objects.update(
DiagramGrid._triangle_objects(triangle))
else:
# No more weldings found. Try to attach triangles by
# vertices.
new_obj = DiagramGrid._grow_pseudopod(
triangles, fringe, grid, skeleton, placed_objects)
if not new_obj:
# No more triangles can be attached, not even by
# the edge. We will set up a new diagram out of
# what has been left, laid it out independently,
# and then attach it to this one.
remaining_objects = all_objects - placed_objects
remaining_diagram = diagram.subdiagram_from_objects(
FiniteSet(*remaining_objects))
remaining_grid = DiagramGrid(remaining_diagram)
# Now, let's glue ``remaining_grid`` to ``grid``.
final_width = grid.width + remaining_grid.width
final_height = max(grid.height, remaining_grid.height)
final_grid = _GrowableGrid(final_width, final_height)
for i in range(grid.width):
for j in range(grid.height):
final_grid[i, j] = grid[i, j]
start_j = grid.width
for i in range(remaining_grid.height):
for j in range(remaining_grid.width):
final_grid[i, start_j + j] = remaining_grid[i, j]
return final_grid
placed_objects.add(new_obj)
triangles = DiagramGrid._drop_irrelevant_triangles(
triangles, placed_objects)
return grid
@staticmethod
def _get_undirected_graph(objects, merged_morphisms):
"""
Given the objects and the relevant morphisms of a diagram,
returns the adjacency lists of the underlying undirected
graph.
"""
adjlists = {}
for obj in objects:
adjlists[obj] = []
for morphism in merged_morphisms:
adjlists[morphism.domain].append(morphism.codomain)
adjlists[morphism.codomain].append(morphism.domain)
# Assure that the objects in the adjacency list are always in
# the same order.
for obj in adjlists.keys():
adjlists[obj].sort(key=default_sort_key)
return adjlists
@staticmethod
def _sequential_layout(diagram, merged_morphisms):
r"""
Lays out the diagram in "sequential" layout. This method
will attempt to produce a result as close to a line as
possible. For linear diagrams, the result will actually be a
line.
"""
objects = diagram.objects
sorted_objects = sorted(objects, key=default_sort_key)
# Set up the adjacency lists of the underlying undirected
# graph of ``merged_morphisms``.
adjlists = DiagramGrid._get_undirected_graph(objects, merged_morphisms)
# Find an object with the minimal degree. This is going to be
# the root.
root = sorted_objects[0]
mindegree = len(adjlists[root])
for obj in sorted_objects:
current_degree = len(adjlists[obj])
if current_degree < mindegree:
root = obj
mindegree = current_degree
grid = _GrowableGrid(1, 1)
grid[0, 0] = root
placed_objects = {root}
def place_objects(pt, placed_objects):
"""
Does depth-first search in the underlying graph of the
diagram and places the objects en route.
"""
# We will start placing new objects from here.
new_pt = (pt[0], pt[1] + 1)
for adjacent_obj in adjlists[grid[pt]]:
if adjacent_obj in placed_objects:
# This object has already been placed.
continue
DiagramGrid._put_object(new_pt, adjacent_obj, grid, [])
placed_objects.add(adjacent_obj)
placed_objects.update(place_objects(new_pt, placed_objects))
new_pt = (new_pt[0] + 1, new_pt[1])
return placed_objects
place_objects((0, 0), placed_objects)
return grid
@staticmethod
def _drop_inessential_morphisms(merged_morphisms):
r"""
Removes those morphisms which should appear in the diagram,
but which have no relevance to object layout.
Currently this removes "loop" morphisms: the non-identity
morphisms with the same domains and codomains.
"""
morphisms = [m for m in merged_morphisms if m.domain != m.codomain]
return morphisms
@staticmethod
def _get_connected_components(objects, merged_morphisms):
"""
Given a container of morphisms, returns a list of connected
components formed by these morphisms. A connected component
is represented by a diagram consisting of the corresponding
morphisms.
"""
component_index = {}
for o in objects:
component_index[o] = None
# Get the underlying undirected graph of the diagram.
adjlist = DiagramGrid._get_undirected_graph(objects, merged_morphisms)
def traverse_component(object, current_index):
"""
Does a depth-first search traversal of the component
containing ``object``.
"""
component_index[object] = current_index
for o in adjlist[object]:
if component_index[o] is None:
traverse_component(o, current_index)
# Traverse all components.
current_index = 0
for o in adjlist:
if component_index[o] is None:
traverse_component(o, current_index)
current_index += 1
# List the objects of the components.
component_objects = [[] for i in range(current_index)]
for o, idx in component_index.items():
component_objects[idx].append(o)
# Finally, list the morphisms belonging to each component.
#
# Note: If some objects are isolated, they will not get any
# morphisms at this stage, and since the layout algorithm
# relies, we are essentially going to lose this object.
# Therefore, check if there are isolated objects and, for each
# of them, provide the trivial identity morphism. It will get
# discarded later, but the object will be there.
component_morphisms = []
for component in component_objects:
current_morphisms = {}
for m in merged_morphisms:
if (m.domain in component) and (m.codomain in component):
current_morphisms[m] = merged_morphisms[m]
if len(component) == 1:
# Let's add an identity morphism, for the sake of
# surely having morphisms in this component.
current_morphisms[IdentityMorphism(component[0])] = FiniteSet()
component_morphisms.append(Diagram(current_morphisms))
return component_morphisms
def __init__(self, diagram, groups=None, **hints):
premises = DiagramGrid._simplify_morphisms(diagram.premises)
conclusions = DiagramGrid._simplify_morphisms(diagram.conclusions)
all_merged_morphisms = DiagramGrid._merge_premises_conclusions(
premises, conclusions)
merged_morphisms = DiagramGrid._drop_inessential_morphisms(
all_merged_morphisms)
# Store the merged morphisms for later use.
self._morphisms = all_merged_morphisms
components = DiagramGrid._get_connected_components(
diagram.objects, all_merged_morphisms)
if groups and (groups != diagram.objects):
# Lay out the diagram according to the groups.
self._grid = DiagramGrid._handle_groups(
diagram, groups, merged_morphisms, hints)
elif len(components) > 1:
# Note that we check for connectedness _before_ checking
# the layout hints because the layout strategies don't
# know how to deal with disconnected diagrams.
# The diagram is disconnected. Lay out the components
# independently.
grids = []
# Sort the components to eventually get the grids arranged
# in a fixed, hash-independent order.
components = sorted(components, key=default_sort_key)
for component in components:
grid = DiagramGrid(component, **hints)
grids.append(grid)
# Throw the grids together, in a line.
total_width = sum(g.width for g in grids)
total_height = max(g.height for g in grids)
grid = _GrowableGrid(total_width, total_height)
start_j = 0
for g in grids:
for i in range(g.height):
for j in range(g.width):
grid[i, start_j + j] = g[i, j]
start_j += g.width
self._grid = grid
elif "layout" in hints:
if hints["layout"] == "sequential":
self._grid = DiagramGrid._sequential_layout(
diagram, merged_morphisms)
else:
self._grid = DiagramGrid._generic_layout(diagram, merged_morphisms)
if hints.get("transpose"):
# Transpose the resulting grid.
grid = _GrowableGrid(self._grid.height, self._grid.width)
for i in range(self._grid.height):
for j in range(self._grid.width):
grid[j, i] = self._grid[i, j]
self._grid = grid
@property
def width(self):
"""
Returns the number of columns in this diagram layout.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.width
2
"""
return self._grid.width
@property
def height(self):
"""
Returns the number of rows in this diagram layout.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.height
2
"""
return self._grid.height
def __getitem__(self, i_j):
"""
Returns the object placed in the row ``i`` and column ``j``.
The indices are 0-based.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> (grid[0, 0], grid[0, 1])
(Object("A"), Object("B"))
>>> (grid[1, 0], grid[1, 1])
(None, Object("C"))
"""
i, j = i_j
return self._grid[i, j]
@property
def morphisms(self):
"""
Returns those morphisms (and their properties) which are
sufficiently meaningful to be drawn.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.morphisms
{NamedMorphism(Object("A"), Object("B"), "f"): EmptySet(),
NamedMorphism(Object("B"), Object("C"), "g"): EmptySet()}
"""
return self._morphisms
def __str__(self):
"""
Produces a string representation of this class.
This method returns a string representation of the underlying
list of lists of objects.
Examples
========
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> print(grid)
[[Object("A"), Object("B")],
[None, Object("C")]]
"""
return repr(self._grid._array)
class ArrowStringDescription(object):
r"""
Stores the information necessary for producing an Xy-pic
description of an arrow.
The principal goal of this class is to abstract away the string
representation of an arrow and to also provide the functionality
to produce the actual Xy-pic string.
``unit`` sets the unit which will be used to specify the amount of
curving and other distances. ``horizontal_direction`` should be a
string of ``"r"`` or ``"l"`` specifying the horizontal offset of the
target cell of the arrow relatively to the current one.
``vertical_direction`` should specify the vertical offset using a
series of either ``"d"`` or ``"u"``. ``label_position`` should be
either ``"^"``, ``"_"``, or ``"|"`` to specify that the label should
be positioned above the arrow, below the arrow or just over the arrow,
in a break. Note that the notions "above" and "below" are relative
to arrow direction. ``label`` stores the morphism label.
This works as follows (disregard the yet unexplained arguments):
>>> from sympy.categories.diagram_drawing import ArrowStringDescription
>>> astr = ArrowStringDescription(
... unit="mm", curving=None, curving_amount=None,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> print(str(astr))
\ar[dr]_{f}
``curving`` should be one of ``"^"``, ``"_"`` to specify in which
direction the arrow is going to curve. ``curving_amount`` is a number
describing how many ``unit``'s the morphism is going to curve:
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> print(str(astr))
\ar@/^12mm/[dr]_{f}
``looping_start`` and ``looping_end`` are currently only used for
loop morphisms, those which have the same domain and codomain.
These two attributes should store a valid Xy-pic direction and
specify, correspondingly, the direction the arrow gets out into
and the direction the arrow gets back from:
>>> astr = ArrowStringDescription(
... unit="mm", curving=None, curving_amount=None,
... looping_start="u", looping_end="l", horizontal_direction="",
... vertical_direction="", label_position="_", label="f")
>>> print(str(astr))
\ar@(u,l)[]_{f}
``label_displacement`` controls how far the arrow label is from
the ends of the arrow. For example, to position the arrow label
near the arrow head, use ">":
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> astr.label_displacement = ">"
>>> print(str(astr))
\ar@/^12mm/[dr]_>{f}
Finally, ``arrow_style`` is used to specify the arrow style. To
get a dashed arrow, for example, use "{-->}" as arrow style:
>>> astr = ArrowStringDescription(
... unit="mm", curving="^", curving_amount=12,
... looping_start=None, looping_end=None, horizontal_direction="d",
... vertical_direction="r", label_position="_", label="f")
>>> astr.arrow_style = "{-->}"
>>> print(str(astr))
\ar@/^12mm/@{-->}[dr]_{f}
Notes
=====
Instances of :class:`ArrowStringDescription` will be constructed
by :class:`XypicDiagramDrawer` and provided for further use in
formatters. The user is not expected to construct instances of
:class:`ArrowStringDescription` themselves.
To be able to properly utilise this class, the reader is encouraged
to checkout the Xy-pic user guide, available at [Xypic].
See Also
========
XypicDiagramDrawer
References
==========
[Xypic] http://xy-pic.sourceforge.net/
"""
def __init__(self, unit, curving, curving_amount, looping_start,
looping_end, horizontal_direction, vertical_direction,
label_position, label):
self.unit = unit
self.curving = curving
self.curving_amount = curving_amount
self.looping_start = looping_start
self.looping_end = looping_end
self.horizontal_direction = horizontal_direction
self.vertical_direction = vertical_direction
self.label_position = label_position
self.label = label
self.label_displacement = ""
self.arrow_style = ""
# This flag shows that the position of the label of this
# morphism was set while typesetting a curved morphism and
# should not be modified later.
self.forced_label_position = False
def __str__(self):
if self.curving:
curving_str = "@/%s%d%s/" % (self.curving, self.curving_amount,
self.unit)
else:
curving_str = ""
if self.looping_start and self.looping_end:
looping_str = "@(%s,%s)" % (self.looping_start, self.looping_end)
else:
looping_str = ""
if self.arrow_style:
style_str = "@" + self.arrow_style
else:
style_str = ""
return "\\ar%s%s%s[%s%s]%s%s{%s}" % \
(curving_str, looping_str, style_str, self.horizontal_direction,
self.vertical_direction, self.label_position,
self.label_displacement, self.label)
class XypicDiagramDrawer(object):
r"""
Given a :class:`Diagram` and the corresponding
:class:`DiagramGrid`, produces the Xy-pic representation of the
diagram.
The most important method in this class is ``draw``. Consider the
following triangle diagram:
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import DiagramGrid, XypicDiagramDrawer
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
To draw this diagram, its objects need to be laid out with a
:class:`DiagramGrid`::
>>> grid = DiagramGrid(diagram)
Finally, the drawing:
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
For further details see the docstring of this method.
To control the appearance of the arrows, formatters are used. The
dictionary ``arrow_formatters`` maps morphisms to formatter
functions. A formatter is accepts an
:class:`ArrowStringDescription` and is allowed to modify any of
the arrow properties exposed thereby. For example, to have all
morphisms with the property ``unique`` appear as dashed arrows,
and to have their names prepended with `\exists !`, the following
should be done:
>>> def formatter(astr):
... astr.label = r"\exists !" + astr.label
... astr.arrow_style = "{-->}"
>>> drawer.arrow_formatters["unique"] = formatter
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar@{-->}[d]_{\exists !g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
To modify the appearance of all arrows in the diagram, set
``default_arrow_formatter``. For example, to place all morphism
labels a little bit farther from the arrow head so that they look
more centred, do as follows:
>>> def default_formatter(astr):
... astr.label_displacement = "(0.45)"
>>> drawer.default_arrow_formatter = default_formatter
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar@{-->}[d]_(0.45){\exists !g\circ f} \ar[r]^(0.45){f} & B \ar[ld]^(0.45){g} \\
C &
}
In some diagrams some morphisms are drawn as curved arrows.
Consider the following diagram:
>>> D = Object("D")
>>> E = Object("E")
>>> h = NamedMorphism(D, A, "h")
>>> k = NamedMorphism(D, B, "k")
>>> diagram = Diagram([f, g, h, k])
>>> grid = DiagramGrid(diagram)
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_3mm/[ll]_{h} \\
& C &
}
To control how far the morphisms are curved by default, one can
use the ``unit`` and ``default_curving_amount`` attributes:
>>> drawer.unit = "cm"
>>> drawer.default_curving_amount = 1
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_1cm/[ll]_{h} \\
& C &
}
In some diagrams, there are multiple curved morphisms between the
same two objects. To control by how much the curving changes
between two such successive morphisms, use
``default_curving_step``:
>>> drawer.default_curving_step = 1
>>> h1 = NamedMorphism(A, D, "h1")
>>> diagram = Diagram([f, g, h, k, h1])
>>> grid = DiagramGrid(diagram)
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[r]_{f} \ar@/^1cm/[rr]^{h_{1}} & B \ar[d]^{g} & D \ar[l]^{k} \ar@/_2cm/[ll]_{h} \\
& C &
}
The default value of ``default_curving_step`` is 4 units.
See Also
========
draw, ArrowStringDescription
"""
def __init__(self):
self.unit = "mm"
self.default_curving_amount = 3
self.default_curving_step = 4
# This dictionary maps properties to the corresponding arrow
# formatters.
self.arrow_formatters = {}
# This is the default arrow formatter which will be applied to
# each arrow independently of its properties.
self.default_arrow_formatter = None
@staticmethod
def _process_loop_morphism(i, j, grid, morphisms_str_info, object_coords):
"""
Produces the information required for constructing the string
representation of a loop morphism. This function is invoked
from ``_process_morphism``.
See Also
========
_process_morphism
"""
curving = ""
label_pos = "^"
looping_start = ""
looping_end = ""
# This is a loop morphism. Count how many morphisms stick
# in each of the four quadrants. Note that straight
# vertical and horizontal morphisms count in two quadrants
# at the same time (i.e., a morphism going up counts both
# in the first and the second quadrants).
# The usual numbering (counterclockwise) of quadrants
# applies.
quadrant = [0, 0, 0, 0]
obj = grid[i, j]
for m, m_str_info in morphisms_str_info.items():
if (m.domain == obj) and (m.codomain == obj):
# That's another loop morphism. Check how it
# loops and mark the corresponding quadrants as
# busy.
(l_s, l_e) = (m_str_info.looping_start, m_str_info.looping_end)
if (l_s, l_e) == ("r", "u"):
quadrant[0] += 1
elif (l_s, l_e) == ("u", "l"):
quadrant[1] += 1
elif (l_s, l_e) == ("l", "d"):
quadrant[2] += 1
elif (l_s, l_e) == ("d", "r"):
quadrant[3] += 1
continue
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
goes_out = True
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
goes_out = False
else:
continue
d_i = end_i - i
d_j = end_j - j
m_curving = m_str_info.curving
if (d_i != 0) and (d_j != 0):
# This is really a diagonal morphism. Detect the
# quadrant.
if (d_i > 0) and (d_j > 0):
quadrant[0] += 1
elif (d_i > 0) and (d_j < 0):
quadrant[1] += 1
elif (d_i < 0) and (d_j < 0):
quadrant[2] += 1
elif (d_i < 0) and (d_j > 0):
quadrant[3] += 1
elif d_i == 0:
# Knowing where the other end of the morphism is
# and which way it goes, we now have to decide
# which quadrant is now the upper one and which is
# the lower one.
if d_j > 0:
if goes_out:
upper_quadrant = 0
lower_quadrant = 3
else:
upper_quadrant = 3
lower_quadrant = 0
else:
if goes_out:
upper_quadrant = 2
lower_quadrant = 1
else:
upper_quadrant = 1
lower_quadrant = 2
if m_curving:
if m_curving == "^":
quadrant[upper_quadrant] += 1
elif m_curving == "_":
quadrant[lower_quadrant] += 1
else:
# This morphism counts in both upper and lower
# quadrants.
quadrant[upper_quadrant] += 1
quadrant[lower_quadrant] += 1
elif d_j == 0:
# Knowing where the other end of the morphism is
# and which way it goes, we now have to decide
# which quadrant is now the left one and which is
# the right one.
if d_i < 0:
if goes_out:
left_quadrant = 1
right_quadrant = 0
else:
left_quadrant = 0
right_quadrant = 1
else:
if goes_out:
left_quadrant = 3
right_quadrant = 2
else:
left_quadrant = 2
right_quadrant = 3
if m_curving:
if m_curving == "^":
quadrant[left_quadrant] += 1
elif m_curving == "_":
quadrant[right_quadrant] += 1
else:
# This morphism counts in both upper and lower
# quadrants.
quadrant[left_quadrant] += 1
quadrant[right_quadrant] += 1
# Pick the freest quadrant to curve our morphism into.
freest_quadrant = 0
for i in range(4):
if quadrant[i] < quadrant[freest_quadrant]:
freest_quadrant = i
# Now set up proper looping.
(looping_start, looping_end) = [("r", "u"), ("u", "l"), ("l", "d"),
("d", "r")][freest_quadrant]
return (curving, label_pos, looping_start, looping_end)
@staticmethod
def _process_horizontal_morphism(i, j, target_j, grid, morphisms_str_info,
object_coords):
"""
Produces the information required for constructing the string
representation of a horizontal morphism. This function is
invoked from ``_process_morphism``.
See Also
========
_process_morphism
"""
# The arrow is horizontal. Check if it goes from left to
# right (``backwards == False``) or from right to left
# (``backwards == True``).
backwards = False
start = j
end = target_j
if end < start:
(start, end) = (end, start)
backwards = True
# Let's see which objects are there between ``start`` and
# ``end``, and then count how many morphisms stick out
# upwards, and how many stick out downwards.
#
# For example, consider the situation:
#
# B1 C1
# | |
# A--B--C--D
# |
# B2
#
# Between the objects `A` and `D` there are two objects:
# `B` and `C`. Further, there are two morphisms which
# stick out upward (the ones between `B1` and `B` and
# between `C` and `C1`) and one morphism which sticks out
# downward (the one between `B and `B2`).
#
# We need this information to decide how to curve the
# arrow between `A` and `D`. First of all, since there
# are two objects between `A` and `D``, we must curve the
# arrow. Then, we will have it curve downward, because
# there is more space (less morphisms stick out downward
# than upward).
up = []
down = []
straight_horizontal = []
for k in range(start + 1, end):
obj = grid[i, k]
if not obj:
continue
for m in morphisms_str_info:
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
else:
continue
if end_i > i:
down.append(m)
elif end_i < i:
up.append(m)
elif not morphisms_str_info[m].curving:
# This is a straight horizontal morphism,
# because it has no curving.
straight_horizontal.append(m)
if len(up) < len(down):
# More morphisms stick out downward than upward, let's
# curve the morphism up.
if backwards:
curving = "_"
label_pos = "_"
else:
curving = "^"
label_pos = "^"
# Assure that the straight horizontal morphisms have
# their labels on the lower side of the arrow.
for m in straight_horizontal:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if j1 < j2:
m_str_info.label_position = "_"
else:
m_str_info.label_position = "^"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
else:
# More morphisms stick out downward than upward, let's
# curve the morphism up.
if backwards:
curving = "^"
label_pos = "^"
else:
curving = "_"
label_pos = "_"
# Assure that the straight horizontal morphisms have
# their labels on the upper side of the arrow.
for m in straight_horizontal:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if j1 < j2:
m_str_info.label_position = "^"
else:
m_str_info.label_position = "_"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
return (curving, label_pos)
@staticmethod
def _process_vertical_morphism(i, j, target_i, grid, morphisms_str_info,
object_coords):
"""
Produces the information required for constructing the string
representation of a vertical morphism. This function is
invoked from ``_process_morphism``.
See Also
========
_process_morphism
"""
# This arrow is vertical. Check if it goes from top to
# bottom (``backwards == False``) or from bottom to top
# (``backwards == True``).
backwards = False
start = i
end = target_i
if end < start:
(start, end) = (end, start)
backwards = True
# Let's see which objects are there between ``start`` and
# ``end``, and then count how many morphisms stick out to
# the left, and how many stick out to the right.
#
# See the corresponding comment in the previous branch of
# this if-statement for more details.
left = []
right = []
straight_vertical = []
for k in range(start + 1, end):
obj = grid[k, j]
if not obj:
continue
for m in morphisms_str_info:
if m.domain == obj:
(end_i, end_j) = object_coords[m.codomain]
elif m.codomain == obj:
(end_i, end_j) = object_coords[m.domain]
else:
continue
if end_j > j:
right.append(m)
elif end_j < j:
left.append(m)
elif not morphisms_str_info[m].curving:
# This is a straight vertical morphism,
# because it has no curving.
straight_vertical.append(m)
if len(left) < len(right):
# More morphisms stick out to the left than to the
# right, let's curve the morphism to the right.
if backwards:
curving = "^"
label_pos = "^"
else:
curving = "_"
label_pos = "_"
# Assure that the straight vertical morphisms have
# their labels on the left side of the arrow.
for m in straight_vertical:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if i1 < i2:
m_str_info.label_position = "^"
else:
m_str_info.label_position = "_"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
else:
# More morphisms stick out to the right than to the
# left, let's curve the morphism to the left.
if backwards:
curving = "_"
label_pos = "_"
else:
curving = "^"
label_pos = "^"
# Assure that the straight vertical morphisms have
# their labels on the right side of the arrow.
for m in straight_vertical:
(i1, j1) = object_coords[m.domain]
(i2, j2) = object_coords[m.codomain]
m_str_info = morphisms_str_info[m]
if i1 < i2:
m_str_info.label_position = "_"
else:
m_str_info.label_position = "^"
# Don't allow any further modifications of the
# position of this label.
m_str_info.forced_label_position = True
return (curving, label_pos)
def _process_morphism(self, diagram, grid, morphism, object_coords,
morphisms, morphisms_str_info):
"""
Given the required information, produces the string
representation of ``morphism``.
"""
def repeat_string_cond(times, str_gt, str_lt):
"""
If ``times > 0``, repeats ``str_gt`` ``times`` times.
Otherwise, repeats ``str_lt`` ``-times`` times.
"""
if times > 0:
return str_gt * times
else:
return str_lt * (-times)
def count_morphisms_undirected(A, B):
"""
Counts how many processed morphisms there are between the
two supplied objects.
"""
return len([m for m in morphisms_str_info
if set([m.domain, m.codomain]) == set([A, B])])
def count_morphisms_filtered(dom, cod, curving):
"""
Counts the processed morphisms which go out of ``dom``
into ``cod`` with curving ``curving``.
"""
return len([m for m, m_str_info in morphisms_str_info.items()
if (m.domain, m.codomain) == (dom, cod) and
(m_str_info.curving == curving)])
(i, j) = object_coords[morphism.domain]
(target_i, target_j) = object_coords[morphism.codomain]
# We now need to determine the direction of
# the arrow.
delta_i = target_i - i
delta_j = target_j - j
vertical_direction = repeat_string_cond(delta_i,
"d", "u")
horizontal_direction = repeat_string_cond(delta_j,
"r", "l")
curving = ""
label_pos = "^"
looping_start = ""
looping_end = ""
if (delta_i == 0) and (delta_j == 0):
# This is a loop morphism.
(curving, label_pos, looping_start,
looping_end) = XypicDiagramDrawer._process_loop_morphism(
i, j, grid, morphisms_str_info, object_coords)
elif (delta_i == 0) and (abs(j - target_j) > 1):
# This is a horizontal morphism.
(curving, label_pos) = XypicDiagramDrawer._process_horizontal_morphism(
i, j, target_j, grid, morphisms_str_info, object_coords)
elif (delta_j == 0) and (abs(i - target_i) > 1):
# This is a vertical morphism.
(curving, label_pos) = XypicDiagramDrawer._process_vertical_morphism(
i, j, target_i, grid, morphisms_str_info, object_coords)
count = count_morphisms_undirected(morphism.domain, morphism.codomain)
curving_amount = ""
if curving:
# This morphisms should be curved anyway.
curving_amount = self.default_curving_amount + count * \
self.default_curving_step
elif count:
# There are no objects between the domain and codomain of
# the current morphism, but this is not there already are
# some morphisms with the same domain and codomain, so we
# have to curve this one.
curving = "^"
filtered_morphisms = count_morphisms_filtered(
morphism.domain, morphism.codomain, curving)
curving_amount = self.default_curving_amount + \
filtered_morphisms * \
self.default_curving_step
# Let's now get the name of the morphism.
morphism_name = ""
if isinstance(morphism, IdentityMorphism):
morphism_name = "id_{%s}" + latex(obj)
elif isinstance(morphism, CompositeMorphism):
component_names = [latex(Symbol(component.name)) for
component in morphism.components]
component_names.reverse()
morphism_name = "\\circ ".join(component_names)
elif isinstance(morphism, NamedMorphism):
morphism_name = latex(Symbol(morphism.name))
return ArrowStringDescription(
self.unit, curving, curving_amount, looping_start,
looping_end, horizontal_direction, vertical_direction,
label_pos, morphism_name)
@staticmethod
def _check_free_space_horizontal(dom_i, dom_j, cod_j, grid):
"""
For a horizontal morphism, checks whether there is free space
(i.e., space not occupied by any objects) above the morphism
or below it.
"""
if dom_j < cod_j:
(start, end) = (dom_j, cod_j)
backwards = False
else:
(start, end) = (cod_j, dom_j)
backwards = True
# Check for free space above.
if dom_i == 0:
free_up = True
else:
free_up = all([grid[dom_i - 1, j] for j in
range(start, end + 1)])
# Check for free space below.
if dom_i == grid.height - 1:
free_down = True
else:
free_down = all([not grid[dom_i + 1, j] for j in
range(start, end + 1)])
return (free_up, free_down, backwards)
@staticmethod
def _check_free_space_vertical(dom_i, cod_i, dom_j, grid):
"""
For a vertical morphism, checks whether there is free space
(i.e., space not occupied by any objects) to the left of the
morphism or to the right of it.
"""
if dom_i < cod_i:
(start, end) = (dom_i, cod_i)
backwards = False
else:
(start, end) = (cod_i, dom_i)
backwards = True
# Check if there's space to the left.
if dom_j == 0:
free_left = True
else:
free_left = all([not grid[i, dom_j - 1] for i in
range(start, end + 1)])
if dom_j == grid.width - 1:
free_right = True
else:
free_right = all([not grid[i, dom_j + 1] for i in
range(start, end + 1)])
return (free_left, free_right, backwards)
@staticmethod
def _check_free_space_diagonal(dom_i, cod_i, dom_j, cod_j, grid):
"""
For a diagonal morphism, checks whether there is free space
(i.e., space not occupied by any objects) above the morphism
or below it.
"""
def abs_xrange(start, end):
if start < end:
return range(start, end + 1)
else:
return range(end, start + 1)
if dom_i < cod_i and dom_j < cod_j:
# This morphism goes from top-left to
# bottom-right.
(start_i, start_j) = (dom_i, dom_j)
(end_i, end_j) = (cod_i, cod_j)
backwards = False
elif dom_i > cod_i and dom_j > cod_j:
# This morphism goes from bottom-right to
# top-left.
(start_i, start_j) = (cod_i, cod_j)
(end_i, end_j) = (dom_i, dom_j)
backwards = True
if dom_i < cod_i and dom_j > cod_j:
# This morphism goes from top-right to
# bottom-left.
(start_i, start_j) = (dom_i, dom_j)
(end_i, end_j) = (cod_i, cod_j)
backwards = True
elif dom_i > cod_i and dom_j < cod_j:
# This morphism goes from bottom-left to
# top-right.
(start_i, start_j) = (cod_i, cod_j)
(end_i, end_j) = (dom_i, dom_j)
backwards = False
# This is an attempt at a fast and furious strategy to
# decide where there is free space on the two sides of
# a diagonal morphism. For a diagonal morphism
# starting at ``(start_i, start_j)`` and ending at
# ``(end_i, end_j)`` the rectangle defined by these
# two points is considered. The slope of the diagonal
# ``alpha`` is then computed. Then, for every cell
# ``(i, j)`` within the rectangle, the slope
# ``alpha1`` of the line through ``(start_i,
# start_j)`` and ``(i, j)`` is considered. If
# ``alpha1`` is between 0 and ``alpha``, the point
# ``(i, j)`` is above the diagonal, if ``alpha1`` is
# between ``alpha`` and infinity, the point is below
# the diagonal. Also note that, with some beforehand
# precautions, this trick works for both the main and
# the secondary diagonals of the rectangle.
# I have considered the possibility to only follow the
# shorter diagonals immediately above and below the
# main (or secondary) diagonal. This, however,
# wouldn't have resulted in much performance gain or
# better detection of outer edges, because of
# relatively small sizes of diagram grids, while the
# code would have become harder to understand.
alpha = float(end_i - start_i)/(end_j - start_j)
free_up = True
free_down = True
for i in abs_xrange(start_i, end_i):
if not free_up and not free_down:
break
for j in abs_xrange(start_j, end_j):
if not free_up and not free_down:
break
if (i, j) == (start_i, start_j):
continue
if j == start_j:
alpha1 = "inf"
else:
alpha1 = float(i - start_i)/(j - start_j)
if grid[i, j]:
if (alpha1 == "inf") or (abs(alpha1) > abs(alpha)):
free_down = False
elif abs(alpha1) < abs(alpha):
free_up = False
return (free_up, free_down, backwards)
def _push_labels_out(self, morphisms_str_info, grid, object_coords):
"""
For all straight morphisms which form the visual boundary of
the laid out diagram, puts their labels on their outer sides.
"""
def set_label_position(free1, free2, pos1, pos2, backwards, m_str_info):
"""
Given the information about room available to one side and
to the other side of a morphism (``free1`` and ``free2``),
sets the position of the morphism label in such a way that
it is on the freer side. This latter operations involves
choice between ``pos1`` and ``pos2``, taking ``backwards``
in consideration.
Thus this function will do nothing if either both ``free1
== True`` and ``free2 == True`` or both ``free1 == False``
and ``free2 == False``. In either case, choosing one side
over the other presents no advantage.
"""
if backwards:
(pos1, pos2) = (pos2, pos1)
if free1 and not free2:
m_str_info.label_position = pos1
elif free2 and not free1:
m_str_info.label_position = pos2
for m, m_str_info in morphisms_str_info.items():
if m_str_info.curving or m_str_info.forced_label_position:
# This is either a curved morphism, and curved
# morphisms have other magic, or the position of this
# label has already been fixed.
continue
if m.domain == m.codomain:
# This is a loop morphism, their labels, again have a
# different magic.
continue
(dom_i, dom_j) = object_coords[m.domain]
(cod_i, cod_j) = object_coords[m.codomain]
if dom_i == cod_i:
# Horizontal morphism.
(free_up, free_down,
backwards) = XypicDiagramDrawer._check_free_space_horizontal(
dom_i, dom_j, cod_j, grid)
set_label_position(free_up, free_down, "^", "_",
backwards, m_str_info)
elif dom_j == cod_j:
# Vertical morphism.
(free_left, free_right,
backwards) = XypicDiagramDrawer._check_free_space_vertical(
dom_i, cod_i, dom_j, grid)
set_label_position(free_left, free_right, "_", "^",
backwards, m_str_info)
else:
# A diagonal morphism.
(free_up, free_down,
backwards) = XypicDiagramDrawer._check_free_space_diagonal(
dom_i, cod_i, dom_j, cod_j, grid)
set_label_position(free_up, free_down, "^", "_",
backwards, m_str_info)
@staticmethod
def _morphism_sort_key(morphism, object_coords):
"""
Provides a morphism sorting key such that horizontal or
vertical morphisms between neighbouring objects come
first, then horizontal or vertical morphisms between more
far away objects, and finally, all other morphisms.
"""
(i, j) = object_coords[morphism.domain]
(target_i, target_j) = object_coords[morphism.codomain]
if morphism.domain == morphism.codomain:
# Loop morphisms should get after diagonal morphisms
# so that the proper direction in which to curve the
# loop can be determined.
return (3, 0, default_sort_key(morphism))
if target_i == i:
return (1, abs(target_j - j), default_sort_key(morphism))
if target_j == j:
return (1, abs(target_i - i), default_sort_key(morphism))
# Diagonal morphism.
return (2, 0, default_sort_key(morphism))
@staticmethod
def _build_xypic_string(diagram, grid, morphisms,
morphisms_str_info, diagram_format):
"""
Given a collection of :class:`ArrowStringDescription`
describing the morphisms of a diagram and the object layout
information of a diagram, produces the final Xy-pic picture.
"""
# Build the mapping between objects and morphisms which have
# them as domains.
object_morphisms = {}
for obj in diagram.objects:
object_morphisms[obj] = []
for morphism in morphisms:
object_morphisms[morphism.domain].append(morphism)
result = "\\xymatrix%s{\n" % diagram_format
for i in range(grid.height):
for j in range(grid.width):
obj = grid[i, j]
if obj:
result += latex(obj) + " "
morphisms_to_draw = object_morphisms[obj]
for morphism in morphisms_to_draw:
result += str(morphisms_str_info[morphism]) + " "
# Don't put the & after the last column.
if j < grid.width - 1:
result += "& "
# Don't put the line break after the last row.
if i < grid.height - 1:
result += "\\\\"
result += "\n"
result += "}\n"
return result
def draw(self, diagram, grid, masked=None, diagram_format=""):
r"""
Returns the Xy-pic representation of ``diagram`` laid out in
``grid``.
Consider the following simple triangle diagram.
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import DiagramGrid, XypicDiagramDrawer
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
To draw this diagram, its objects need to be laid out with a
:class:`DiagramGrid`::
>>> grid = DiagramGrid(diagram)
Finally, the drawing:
>>> drawer = XypicDiagramDrawer()
>>> print(drawer.draw(diagram, grid))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
The argument ``masked`` can be used to skip morphisms in the
presentation of the diagram:
>>> print(drawer.draw(diagram, grid, masked=[g * f]))
\xymatrix{
A \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
Finally, the ``diagram_format`` argument can be used to
specify the format string of the diagram. For example, to
increase the spacing by 1 cm, proceeding as follows:
>>> print(drawer.draw(diagram, grid, diagram_format="@+1cm"))
\xymatrix@+1cm{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
"""
# This method works in several steps. It starts by removing
# the masked morphisms, if necessary, and then maps objects to
# their positions in the grid (coordinate tuples). Remember
# that objects are unique in ``Diagram`` and in the layout
# produced by ``DiagramGrid``, so every object is mapped to a
# single coordinate pair.
#
# The next step is the central step and is concerned with
# analysing the morphisms of the diagram and deciding how to
# draw them. For example, how to curve the arrows is decided
# at this step. The bulk of the analysis is implemented in
# ``_process_morphism``, to the result of which the
# appropriate formatters are applied.
#
# The result of the previous step is a list of
# ``ArrowStringDescription``. After the analysis and
# application of formatters, some extra logic tries to assure
# better positioning of morphism labels (for example, an
# attempt is made to avoid the situations when arrows cross
# labels). This functionality constitutes the next step and
# is implemented in ``_push_labels_out``. Note that label
# positions which have been set via a formatter are not
# affected in this step.
#
# Finally, at the closing step, the array of
# ``ArrowStringDescription`` and the layout information
# incorporated in ``DiagramGrid`` are combined to produce the
# resulting Xy-pic picture. This part of code lies in
# ``_build_xypic_string``.
if not masked:
morphisms_props = grid.morphisms
else:
morphisms_props = {}
for m, props in grid.morphisms.items():
if m in masked:
continue
morphisms_props[m] = props
# Build the mapping between objects and their position in the
# grid.
object_coords = {}
for i in range(grid.height):
for j in range(grid.width):
if grid[i, j]:
object_coords[grid[i, j]] = (i, j)
morphisms = sorted(morphisms_props,
key=lambda m: XypicDiagramDrawer._morphism_sort_key(
m, object_coords))
# Build the tuples defining the string representations of
# morphisms.
morphisms_str_info = {}
for morphism in morphisms:
string_description = self._process_morphism(
diagram, grid, morphism, object_coords, morphisms,
morphisms_str_info)
if self.default_arrow_formatter:
self.default_arrow_formatter(string_description)
for prop in morphisms_props[morphism]:
# prop is a Symbol. TODO: Find out why.
if prop.name in self.arrow_formatters:
formatter = self.arrow_formatters[prop.name]
formatter(string_description)
morphisms_str_info[morphism] = string_description
# Reposition the labels a bit.
self._push_labels_out(morphisms_str_info, grid, object_coords)
return XypicDiagramDrawer._build_xypic_string(
diagram, grid, morphisms, morphisms_str_info, diagram_format)
def xypic_draw_diagram(diagram, masked=None, diagram_format="",
groups=None, **hints):
r"""
Provides a shortcut combining :class:`DiagramGrid` and
:class:`XypicDiagramDrawer`. Returns an Xy-pic presentation of
``diagram``. The argument ``masked`` is a list of morphisms which
will be not be drawn. The argument ``diagram_format`` is the
format string inserted after "\xymatrix". ``groups`` should be a
set of logical groups. The ``hints`` will be passed directly to
the constructor of :class:`DiagramGrid`.
For more information about the arguments, see the docstrings of
:class:`DiagramGrid` and ``XypicDiagramDrawer.draw``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import xypic_draw_diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g], {g * f: "unique"})
>>> print(xypic_draw_diagram(diagram))
\xymatrix{
A \ar[d]_{g\circ f} \ar[r]^{f} & B \ar[ld]^{g} \\
C &
}
See Also
========
XypicDiagramDrawer, DiagramGrid
"""
grid = DiagramGrid(diagram, groups, **hints)
drawer = XypicDiagramDrawer()
return drawer.draw(diagram, grid, masked, diagram_format)
@doctest_depends_on(exe=('latex', 'dvipng'), modules=('pyglet',))
def preview_diagram(diagram, masked=None, diagram_format="", groups=None,
output='png', viewer=None, euler=True, **hints):
"""
Combines the functionality of ``xypic_draw_diagram`` and
``sympy.printing.preview``. The arguments ``masked``,
``diagram_format``, ``groups``, and ``hints`` are passed to
``xypic_draw_diagram``, while ``output``, ``viewer, and ``euler``
are passed to ``preview``.
Examples
========
>>> from sympy.categories import Object, NamedMorphism, Diagram
>>> from sympy.categories import preview_diagram
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> d = Diagram([f, g], {g * f: "unique"})
>>> preview_diagram(d)
See Also
========
xypic_diagram_drawer
"""
from sympy.printing import preview
latex_output = xypic_draw_diagram(diagram, masked, diagram_format,
groups, **hints)
preview(latex_output, output, viewer, euler, ("xypic",))
|
79b40931bdf4940c654e624ebafa10acb5aa2051cba21c6c1626a68077935381
|
import itertools
from functools import reduce
from collections import defaultdict
from sympy import Indexed, IndexedBase, Tuple, Sum, Add, S, Integer
from sympy.core.basic import Basic
from sympy.core.sympify import _sympify
from sympy.core.mul import Mul
from sympy.core.compatibility import accumulate, default_sort_key
from sympy.combinatorics import Permutation
from sympy.matrices.expressions import (MatAdd, MatMul, Trace, Transpose,
MatrixSymbol)
from sympy.matrices.expressions.matexpr import MatrixExpr, MatrixElement
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.tensor.array import NDimArray
class _CodegenArrayAbstract(Basic):
@property
def subranks(self):
"""
Returns the ranks of the objects in the uppermost tensor product inside
the current object. In case no tensor products are contained, return
the atomic ranks.
Examples
========
>>> from sympy.codegen.array_utils import CodegenArrayTensorProduct, CodegenArrayContraction
>>> from sympy import MatrixSymbol
>>> M = MatrixSymbol("M", 3, 3)
>>> N = MatrixSymbol("N", 3, 3)
>>> P = MatrixSymbol("P", 3, 3)
Important: do not confuse the rank of the matrix with the rank of an array.
>>> tp = CodegenArrayTensorProduct(M, N, P)
>>> tp.subranks
[2, 2, 2]
>>> co = CodegenArrayContraction(tp, (1, 2), (3, 4))
>>> co.subranks
[2, 2, 2]
"""
return self._subranks[:]
def subrank(self):
"""
The sum of ``subranks``.
"""
return sum(self.subranks)
@property
def shape(self):
return self._shape
class CodegenArrayContraction(_CodegenArrayAbstract):
r"""
This class is meant to represent contractions of arrays in a form easily
processable by the code printers.
"""
def __new__(cls, expr, *contraction_indices, **kwargs):
contraction_indices = _sort_contraction_indices(contraction_indices)
expr = _sympify(expr)
if len(contraction_indices) == 0:
return expr
if isinstance(expr, CodegenArrayContraction):
return cls._flatten(expr, *contraction_indices)
obj = Basic.__new__(cls, expr, *contraction_indices)
obj._subranks = _get_subranks(expr)
obj._mapping = _get_mapping_from_subranks(obj._subranks)
free_indices_to_position = {i: i for i in range(sum(obj._subranks)) if all([i not in cind for cind in contraction_indices])}
obj._free_indices_to_position = free_indices_to_position
shape = expr.shape
if shape:
# Check that no contraction happens when the shape is mismatched:
for i in contraction_indices:
if len(set(shape[j] for j in i)) != 1:
raise ValueError("contracting indices of different dimensions")
shape = tuple(shp for i, shp in enumerate(shape) if not any(i in j for j in contraction_indices))
obj._shape = shape
return obj
@staticmethod
def _get_free_indices_to_position_map(free_indices, contraction_indices):
free_indices_to_position = {}
flattened_contraction_indices = [j for i in contraction_indices for j in i]
counter = 0
for ind in free_indices:
while counter in flattened_contraction_indices:
counter += 1
free_indices_to_position[ind] = counter
counter += 1
return free_indices_to_position
@staticmethod
def _get_index_shifts(expr):
"""
Get the mapping of indices at the positions before the contraction
occures.
Examples
========
>>> from sympy.codegen.array_utils import CodegenArrayContraction, CodegenArrayTensorProduct
>>> from sympy import MatrixSymbol
>>> M = MatrixSymbol("M", 3, 3)
>>> N = MatrixSymbol("N", 3, 3)
>>> cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), [1, 2])
>>> cg._get_index_shifts(cg)
[0, 2]
Indeed, ``cg`` after the contraction has two dimensions, 0 and 1. They
need to be shifted by 0 and 2 to get the corresponding positions before
the contraction (that is, 0 and 3).
"""
inner_contraction_indices = expr.contraction_indices
all_inner = [j for i in inner_contraction_indices for j in i]
all_inner.sort()
# TODO: add API for total rank and cumulative rank:
total_rank = get_rank(expr)
inner_rank = len(all_inner)
outer_rank = total_rank - inner_rank
shifts = [0 for i in range(outer_rank)]
counter = 0
pointer = 0
for i in range(outer_rank):
while pointer < inner_rank and counter >= all_inner[pointer]:
counter += 1
pointer += 1
shifts[i] += pointer
counter += 1
return shifts
@staticmethod
def _convert_outer_indices_to_inner_indices(expr, *outer_contraction_indices):
shifts = CodegenArrayContraction._get_index_shifts(expr)
outer_contraction_indices = tuple(tuple(shifts[j] + j for j in i) for i in outer_contraction_indices)
return outer_contraction_indices
@staticmethod
def _flatten(expr, *outer_contraction_indices):
inner_contraction_indices = expr.contraction_indices
outer_contraction_indices = CodegenArrayContraction._convert_outer_indices_to_inner_indices(expr, *outer_contraction_indices)
contraction_indices = inner_contraction_indices + outer_contraction_indices
return CodegenArrayContraction(expr.expr, *contraction_indices)
def _get_contraction_tuples(self):
r"""
Return tuples containing the argument index and position within the
argument of the index position.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum, Symbol
>>> from sympy.abc import i, j, k, l, N
>>> from sympy.codegen.array_utils import CodegenArrayContraction, CodegenArrayTensorProduct
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, B), (1, 2))
>>> cg._get_contraction_tuples()
[[(0, 1), (1, 0)]]
Here the contraction pair `(1, 2)` meaning that the 2nd and 3rd indices
of the tensor product `A\otimes B` are contracted, has been transformed
into `(0, 1)` and `(1, 0)`, identifying the same indices in a different
notation. `(0, 1)` is the second index (1) of the first argument (i.e.
0 or `A`). `(1, 0)` is the first index (i.e. 0) of the second
argument (i.e. 1 or `B`).
"""
mapping = self._mapping
return [[mapping[j] for j in i] for i in self.contraction_indices]
@staticmethod
def _contraction_tuples_to_contraction_indices(expr, contraction_tuples):
# TODO: check that `expr` has `.subranks`:
ranks = expr.subranks
cumulative_ranks = [0] + list(accumulate(ranks))
return [tuple(cumulative_ranks[j]+k for j, k in i) for i in contraction_tuples]
@property
def free_indices(self):
return self._free_indices[:]
@property
def free_indices_to_position(self):
return dict(self._free_indices_to_position)
@property
def expr(self):
return self.args[0]
@property
def contraction_indices(self):
return self.args[1:]
def _contraction_indices_to_components(self):
expr = self.expr
if not isinstance(expr, CodegenArrayTensorProduct):
raise NotImplementedError("only for contractions of tensor products")
contraction_indices = self.contraction_indices
args = expr.args
ranks = expr.subranks
mapping = {}
counter = 0
for i, rank in enumerate(ranks):
for j in range(rank):
mapping[counter] = (i, j)
counter += 1
return mapping
def sort_args_by_name(self):
"""
Sort arguments in the tensor product so that their order is lexicographical.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum, Symbol
>>> from sympy.abc import i, j, k, l, N
>>> from sympy.codegen.array_utils import CodegenArrayContraction
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> C = MatrixSymbol("C", N, N)
>>> D = MatrixSymbol("D", N, N)
>>> cg = CodegenArrayContraction.from_MatMul(C*D*A*B)
>>> cg
CodegenArrayContraction(CodegenArrayTensorProduct(C, D, A, B), (1, 2), (3, 4), (5, 6))
>>> cg.sort_args_by_name()
CodegenArrayContraction(CodegenArrayTensorProduct(A, B, C, D), (0, 7), (1, 2), (5, 6))
"""
expr = self.expr
if not isinstance(expr, CodegenArrayTensorProduct):
return self
args = expr.args
sorted_data = sorted(enumerate(args), key=lambda x: default_sort_key(x[1]))
pos_sorted, args_sorted = zip(*sorted_data)
reordering_map = {i: pos_sorted.index(i) for i, arg in enumerate(args)}
contraction_tuples = self._get_contraction_tuples()
contraction_tuples = [[(reordering_map[j], k) for j, k in i] for i in contraction_tuples]
c_tp = CodegenArrayTensorProduct(*args_sorted)
new_contr_indices = self._contraction_tuples_to_contraction_indices(
c_tp,
contraction_tuples
)
return CodegenArrayContraction(c_tp, *new_contr_indices)
def _get_contraction_links(self):
r"""
Returns a dictionary of links between arguments in the tensor product
being contracted.
See the example for an explanation of the values.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum, Symbol
>>> from sympy.abc import i, j, k, l, N
>>> from sympy.codegen.array_utils import CodegenArrayContraction
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> C = MatrixSymbol("C", N, N)
>>> D = MatrixSymbol("D", N, N)
Matrix multiplications are pairwise contractions between neighboring
matrices:
`A_{ij} B_{jk} C_{kl} D_{lm}`
>>> cg = CodegenArrayContraction.from_MatMul(A*B*C*D)
>>> cg
CodegenArrayContraction(CodegenArrayTensorProduct(A, B, C, D), (1, 2), (3, 4), (5, 6))
>>> cg._get_contraction_links()
{0: {1: (1, 0)}, 1: {0: (0, 1), 1: (2, 0)}, 2: {0: (1, 1), 1: (3, 0)}, 3: {0: (2, 1)}}
This dictionary is interpreted as follows: argument in position 0 (i.e.
matrix `A`) has its second index (i.e. 1) contracted to `(1, 0)`, that
is argument in position 1 (matrix `B`) on the first index slot of `B`,
this is the contraction provided by the index `j` from `A`.
The argument in position 1 (that is, matrix `B`) has two contractions,
the ones provided by the indices `j` and `k`, respectively the first
and second indices (0 and 1 in the sub-dict). The link `(0, 1)` and
`(2, 0)` respectively. `(0, 1)` is the index slot 1 (the 2nd) of
argument in position 0 (that is, `A_{\ldot j}`), and so on.
"""
return _get_contraction_links(self.subranks, *self.contraction_indices)
@staticmethod
def from_MatMul(expr):
args_nonmat = []
args = []
contractions = []
for arg in expr.args:
if isinstance(arg, MatrixExpr):
args.append(arg)
else:
args_nonmat.append(arg)
contractions = [(2*i+1, 2*i+2) for i in range(len(args)-1)]
return Mul.fromiter(args_nonmat)*CodegenArrayContraction(
CodegenArrayTensorProduct(*args),
*contractions
)
def get_shape(expr):
if hasattr(expr, "shape"):
return expr.shape
return ()
class CodegenArrayTensorProduct(_CodegenArrayAbstract):
r"""
Class to represent the tensor product of array-like objects.
"""
def __new__(cls, *args):
args = [_sympify(arg) for arg in args]
args = cls._flatten(args)
ranks = [get_rank(arg) for arg in args]
if len(args) == 1:
return args[0]
# If there are contraction objects inside, transform the whole
# expression into `CodegenArrayContraction`:
contractions = {i: arg for i, arg in enumerate(args) if isinstance(arg, CodegenArrayContraction)}
if contractions:
cumulative_ranks = list(accumulate([0] + ranks))[:-1]
tp = cls(*[arg.expr if isinstance(arg, CodegenArrayContraction) else arg for arg in args])
contraction_indices = [tuple(cumulative_ranks[i] + k for k in j) for i, arg in contractions.items() for j in arg.contraction_indices]
return CodegenArrayContraction(tp, *contraction_indices)
#newargs = [i for i in args if hasattr(i, "shape")]
#coeff = reduce(lambda x, y: x*y, [i for i in args if not hasattr(i, "shape")], S.One)
#newargs[0] *= coeff
obj = Basic.__new__(cls, *args)
obj._subranks = ranks
shapes = [get_shape(i) for i in args]
if any(i is None for i in shapes):
obj._shape = None
else:
obj._shape = tuple(j for i in shapes for j in i)
return obj
@classmethod
def _flatten(cls, args):
args = [i for arg in args for i in (arg.args if isinstance(arg, cls) else [arg])]
return args
class CodegenArrayElementwiseAdd(_CodegenArrayAbstract):
r"""
Class for elementwise array additions.
"""
def __new__(cls, *args):
args = [_sympify(arg) for arg in args]
obj = Basic.__new__(cls, *args)
ranks = [get_rank(arg) for arg in args]
ranks = list(set(ranks))
if len(ranks) != 1:
raise ValueError("summing arrays of different ranks")
obj._subranks = ranks
shapes = [arg.shape for arg in args]
if len(set([i for i in shapes if i is not None])) > 1:
raise ValueError("mismatching shapes in addition")
if any(i is None for i in shapes):
obj._shape = None
else:
obj._shape = shapes[0]
return obj
class CodegenArrayPermuteDims(_CodegenArrayAbstract):
r"""
Class to represent permutation of axes of arrays.
Examples
========
>>> from sympy.codegen.array_utils import CodegenArrayPermuteDims
>>> from sympy import MatrixSymbol
>>> M = MatrixSymbol("M", 3, 3)
>>> cg = CodegenArrayPermuteDims(M, [1, 0])
The object ``cg`` represents the transposition of ``M``, as the permutation
``[1, 0]`` will act on its indices by switching them:
`M_{ij} \Rightarrow M_{ji}`
This is evident when transforming back to matrix form:
>>> from sympy.codegen.array_utils import recognize_matrix_expression
>>> recognize_matrix_expression(cg)
M.T
>>> N = MatrixSymbol("N", 3, 2)
>>> cg = CodegenArrayPermuteDims(N, [1, 0])
>>> cg.shape
(2, 3)
"""
def __new__(cls, expr, permutation):
from sympy.combinatorics import Permutation
expr = _sympify(expr)
permutation = Permutation(permutation)
plist = permutation.args[0]
if plist == sorted(plist):
return expr
obj = Basic.__new__(cls, expr, permutation)
obj._subranks = [get_rank(expr)]
shape = expr.shape
if shape is None:
obj._shape = None
else:
obj._shape = tuple(shape[permutation(i)] for i in range(len(shape)))
return obj
@property
def expr(self):
return self.args[0]
@property
def permutation(self):
return self.args[1]
def nest_permutation(self):
r"""
Nest the permutation down the expression tree.
Examples
========
>>> from sympy.codegen.array_utils import (CodegenArrayPermuteDims, CodegenArrayTensorProduct, nest_permutation)
>>> from sympy import MatrixSymbol
>>> from sympy.combinatorics import Permutation
>>> Permutation.print_cyclic = True
>>> M = MatrixSymbol("M", 3, 3)
>>> N = MatrixSymbol("N", 3, 3)
>>> cg = CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [1, 0, 3, 2])
>>> cg
CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), (0 1)(2 3))
>>> nest_permutation(cg)
CodegenArrayTensorProduct(CodegenArrayPermuteDims(M, (0 1)), CodegenArrayPermuteDims(N, (0 1)))
In ``cg`` both ``M`` and ``N`` are transposed. The cyclic
representation of the permutation after the tensor product is
`(0 1)(2 3)`. After nesting it down the expression tree, the usual
transposition permutation `(0 1)` appears.
"""
expr = self.expr
if isinstance(expr, CodegenArrayTensorProduct):
# Check if the permutation keeps the subranks separated:
subranks = expr.subranks
subrank = expr.subrank()
l = list(range(subrank))
p = [self.permutation(i) for i in l]
dargs = {}
counter = 0
for i, arg in zip(subranks, expr.args):
p0 = p[counter:counter+i]
counter += i
s0 = sorted(p0)
if not all([s0[j+1]-s0[j] == 1 for j in range(len(s0)-1)]):
# Cross-argument permutations, impossible to nest the object:
return self
subpermutation = [p0.index(j) for j in s0]
dargs[s0[0]] = CodegenArrayPermuteDims(arg, subpermutation)
# Read the arguments sorting the according to the keys of the dict:
args = [dargs[i] for i in sorted(dargs)]
return CodegenArrayTensorProduct(*args)
elif isinstance(expr, CodegenArrayContraction):
# Invert tree hierarchy: put the contraction above.
shifts = expr._get_index_shifts(expr)
cycles = self.permutation.cyclic_form
newcycles = CodegenArrayContraction._convert_outer_indices_to_inner_indices(expr, *cycles)
newpermutation = Permutation(newcycles)
new_contr_indices = [tuple(newpermutation(j) for j in i) for i in expr.contraction_indices]
return CodegenArrayContraction(CodegenArrayPermuteDims(expr.expr, newpermutation), *new_contr_indices)
elif isinstance(expr, CodegenArrayElementwiseAdd):
return CodegenArrayElementwiseAdd(*[CodegenArrayPermuteDims(arg, self.permutation) for arg in expr.args])
return self
def nest_permutation(expr):
if isinstance(expr, CodegenArrayPermuteDims):
return expr.nest_permutation()
else:
return expr
class CodegenArrayDiagonal(_CodegenArrayAbstract):
r"""
Class to represent the diagonal operator.
In a 2-dimensional array it returns the diagonal, this looks like the
operation:
`A_{ij} \rightarrow A_{ii}`
The diagonal over axes 1 and 2 (the second and third) of the tensor product
of two 2-dimensional arrays `A \otimes B` is
`\Big[ A_{ab} B_{cd} \Big]_{abcd} \rightarrow \Big[ A_{ai} B_{id} \Big]_{adi}`
In this last example the array expression has been reduced from
4-dimensional to 3-dimensional. Notice that no contraction has occurred,
rather there is a new index `i` for the diagonal, contraction would have
reduced the array to 2 dimensions.
Notice that the diagonalized out dimensions are added as new dimensions at
the end of the indices.
"""
def __new__(cls, expr, *diagonal_indices):
expr = _sympify(expr)
diagonal_indices = [Tuple(*sorted(i)) for i in diagonal_indices]
if isinstance(expr, CodegenArrayDiagonal):
return cls._flatten(expr, *diagonal_indices)
obj = Basic.__new__(cls, expr, *diagonal_indices)
obj._subranks = _get_subranks(expr)
shape = expr.shape
if shape is None:
obj._shape = None
else:
# Check that no diagonalization happens on indices with mismatched
# dimensions:
for i in diagonal_indices:
if len(set(shape[j] for j in i)) != 1:
raise ValueError("contracting indices of different dimensions")
# Get new shape:
shp1 = tuple(shp for i,shp in enumerate(shape) if not any(i in j for j in diagonal_indices))
shp2 = tuple(shape[i[0]] for i in diagonal_indices)
obj._shape = shp1 + shp2
return obj
@property
def expr(self):
return self.args[0]
@property
def diagonal_indices(self):
return self.args[1:]
@staticmethod
def _flatten(expr, *outer_diagonal_indices):
inner_diagonal_indices = expr.diagonal_indices
all_inner = [j for i in inner_diagonal_indices for j in i]
all_inner.sort()
# TODO: add API for total rank and cumulative rank:
total_rank = get_rank(expr)
inner_rank = len(all_inner)
outer_rank = total_rank - inner_rank
shifts = [0 for i in range(outer_rank)]
counter = 0
pointer = 0
for i in range(outer_rank):
while pointer < inner_rank and counter >= all_inner[pointer]:
counter += 1
pointer += 1
shifts[i] += pointer
counter += 1
outer_diagonal_indices = tuple(tuple(shifts[j] + j for j in i) for i in outer_diagonal_indices)
diagonal_indices = inner_diagonal_indices + outer_diagonal_indices
return CodegenArrayDiagonal(expr.expr, *diagonal_indices)
def get_rank(expr):
if isinstance(expr, (MatrixExpr, MatrixElement)):
return 2
if isinstance(expr, _CodegenArrayAbstract):
return expr.subrank()
if isinstance(expr, NDimArray):
return expr.rank()
if isinstance(expr, Indexed):
return expr.rank
if isinstance(expr, IndexedBase):
shape = expr.shape
if shape is None:
return -1
else:
return len(shape)
if isinstance(expr, _RecognizeMatOp):
return expr.rank()
if isinstance(expr, _RecognizeMatMulLines):
return expr.rank()
return 0
def _get_subranks(expr):
if isinstance(expr, _CodegenArrayAbstract):
return expr.subranks
else:
return [get_rank(expr)]
def _get_mapping_from_subranks(subranks):
mapping = {}
counter = 0
for i, rank in enumerate(subranks):
for j in range(rank):
mapping[counter] = (i, j)
counter += 1
return mapping
def _get_contraction_links(subranks, *contraction_indices):
mapping = _get_mapping_from_subranks(subranks)
contraction_tuples = [[mapping[j] for j in i] for i in contraction_indices]
dlinks = defaultdict(dict)
for links in contraction_tuples:
if len(links) > 2:
raise NotImplementedError("three or more axes contracted at the same time")
(arg1, pos1), (arg2, pos2) = links
dlinks[arg1][pos1] = (arg2, pos2)
dlinks[arg2][pos2] = (arg1, pos1)
return dict(dlinks)
def _sort_contraction_indices(pairing_indices):
pairing_indices = [Tuple(*sorted(i)) for i in pairing_indices]
pairing_indices.sort(key=lambda x: min(x))
return pairing_indices
def _get_diagonal_indices(flattened_indices):
axes_contraction = defaultdict(list)
for i, ind in enumerate(flattened_indices):
if isinstance(ind, (int, Integer)):
# If the indices is a number, there can be no diagonal operation:
continue
axes_contraction[ind].append(i)
axes_contraction = {k: v for k, v in axes_contraction.items() if len(v) > 1}
# Put the diagonalized indices at the end:
ret_indices = [i for i in flattened_indices if i not in axes_contraction]
diag_indices = list(axes_contraction)
diag_indices.sort(key=lambda x: flattened_indices.index(x))
diagonal_indices = [tuple(axes_contraction[i]) for i in diag_indices]
ret_indices += diag_indices
ret_indices = tuple(ret_indices)
return diagonal_indices, ret_indices
def _get_argindex(subindices, ind):
for i, sind in enumerate(subindices):
if ind == sind:
return i
if isinstance(sind, (set, frozenset)) and ind in sind:
return i
raise IndexError("%s not found in %s" % (ind, subindices))
def _codegen_array_parse(expr):
if isinstance(expr, Sum):
function = expr.function
summation_indices = expr.variables
subexpr, subindices = _codegen_array_parse(function)
# Check dimensional consistency:
shape = subexpr.shape
if shape:
for ind, istart, iend in expr.limits:
i = _get_argindex(subindices, ind)
if istart != 0 or iend+1 != shape[i]:
raise ValueError("summation index and array dimension mismatch: %s" % ind)
contraction_indices = []
subindices = list(subindices)
if isinstance(subexpr, CodegenArrayDiagonal):
diagonal_indices = list(subexpr.diagonal_indices)
dindices = subindices[-len(diagonal_indices):]
subindices = subindices[:-len(diagonal_indices)]
for index in summation_indices:
if index in dindices:
position = dindices.index(index)
contraction_indices.append(diagonal_indices[position])
diagonal_indices[position] = None
diagonal_indices = [i for i in diagonal_indices if i is not None]
for i, ind in enumerate(subindices):
if ind in summation_indices:
pass
if diagonal_indices:
subexpr = CodegenArrayDiagonal(subexpr.expr, *diagonal_indices)
else:
subexpr = subexpr.expr
else:
function_args = [subexpr]
subindices = subindices
axes_contraction = defaultdict(list)
for i, ind in enumerate(subindices):
if ind in summation_indices:
axes_contraction[ind].append(i)
subindices[i] = None
for k, v in axes_contraction.items():
contraction_indices.append(tuple(v))
free_indices = [i for i in subindices if i is not None]
indices_ret = list(free_indices)
indices_ret.sort(key=lambda x: free_indices.index(x))
return CodegenArrayContraction(
subexpr,
*contraction_indices,
free_indices=free_indices
), tuple(indices_ret)
if isinstance(expr, Mul):
args, indices = zip(*[_codegen_array_parse(arg) for arg in expr.args])
# Check if there are KroneckerDelta objects:
kronecker_delta_repl = {}
for arg in args:
if not isinstance(arg, KroneckerDelta):
continue
# Diagonalize two indices:
i, j = arg.indices
kindices = set(arg.indices)
if i in kronecker_delta_repl:
kindices.update(kronecker_delta_repl[i])
if j in kronecker_delta_repl:
kindices.update(kronecker_delta_repl[j])
kindices = frozenset(kindices)
for index in kindices:
kronecker_delta_repl[index] = kindices
# Remove KroneckerDelta objects, their relations should be handled by
# CodegenArrayDiagonal:
newargs = []
newindices = []
for arg, loc_indices in zip(args, indices):
if isinstance(arg, KroneckerDelta):
continue
newargs.append(arg)
newindices.append(loc_indices)
flattened_indices = [kronecker_delta_repl.get(j, j) for i in newindices for j in i]
diagonal_indices, ret_indices = _get_diagonal_indices(flattened_indices)
tp = CodegenArrayTensorProduct(*newargs)
if diagonal_indices:
return (CodegenArrayDiagonal(tp, *diagonal_indices), ret_indices)
else:
return tp, ret_indices
if isinstance(expr, MatrixElement):
indices = expr.args[1:]
diagonal_indices, ret_indices = _get_diagonal_indices(indices)
if diagonal_indices:
return (CodegenArrayDiagonal(expr.args[0], *diagonal_indices), ret_indices)
else:
return expr.args[0], ret_indices
if isinstance(expr, Indexed):
indices = expr.indices
diagonal_indices, ret_indices = _get_diagonal_indices(indices)
if diagonal_indices:
return (CodegenArrayDiagonal(expr.base, *diagonal_indices), ret_indices)
else:
return expr.args[0], ret_indices
if isinstance(expr, IndexedBase):
raise NotImplementedError
if isinstance(expr, KroneckerDelta):
return expr, expr.indices
if isinstance(expr, Add):
args, indices = zip(*[_codegen_array_parse(arg) for arg in expr.args])
args = list(args)
# Check if all indices are compatible. Otherwise expand the dimensions:
index0set = set(indices[0])
index0 = indices[0]
for i in range(1, len(args)):
if set(indices[i]) != index0set:
raise NotImplementedError("indices must be the same")
permutation = Permutation([index0.index(j) for j in indices[i]])
# Perform index permutations:
args[i] = CodegenArrayPermuteDims(args[i], permutation)
return CodegenArrayElementwiseAdd(*args), index0
return expr, ()
raise NotImplementedError("could not recognize expression %s" % expr)
def _parse_matrix_expression(expr):
if isinstance(expr, MatMul):
args_nonmat = []
args = []
contractions = []
for arg in expr.args:
if isinstance(arg, MatrixExpr):
args.append(arg)
else:
args_nonmat.append(arg)
contractions = [(2*i+1, 2*i+2) for i in range(len(args)-1)]
return Mul.fromiter(args_nonmat)*CodegenArrayContraction(
CodegenArrayTensorProduct(*[_parse_matrix_expression(arg) for arg in args]),
*contractions
)
elif isinstance(expr, MatAdd):
return CodegenArrayElementwiseAdd(
*[_parse_matrix_expression(arg) for arg in expr.args]
)
elif isinstance(expr, Transpose):
return CodegenArrayPermuteDims(
_parse_matrix_expression(expr.args[0]), [1, 0]
)
else:
return expr
def parse_indexed_expression(expr, first_indices=[]):
r"""
Parse indexed expression into a form useful for code generation.
Examples
========
>>> from sympy.codegen.array_utils import parse_indexed_expression
>>> from sympy import MatrixSymbol, Sum, symbols
>>> from sympy.combinatorics import Permutation
>>> Permutation.print_cyclic = True
>>> i, j, k, d = symbols("i j k d")
>>> M = MatrixSymbol("M", d, d)
>>> N = MatrixSymbol("N", d, d)
Recognize the trace in summation form:
>>> expr = Sum(M[i, i], (i, 0, d-1))
>>> parse_indexed_expression(expr)
CodegenArrayContraction(M, (0, 1))
Recognize the extraction of the diagonal by using the same index `i` on
both axes of the matrix:
>>> expr = M[i, i]
>>> parse_indexed_expression(expr)
CodegenArrayDiagonal(M, (0, 1))
This function can help perform the transformation expressed in two
different mathematical notations as:
`\sum_{j=0}^{N-1} A_{i,j} B_{j,k} \Longrightarrow \mathbf{A}\cdot \mathbf{B}`
Recognize the matrix multiplication in summation form:
>>> expr = Sum(M[i, j]*N[j, k], (j, 0, d-1))
>>> parse_indexed_expression(expr)
CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2))
Specify that ``k`` has to be the starting index:
>>> parse_indexed_expression(expr, first_indices=[k])
CodegenArrayPermuteDims(CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2)), (0 1))
"""
result, indices = _codegen_array_parse(expr)
if not first_indices:
return result
for i in first_indices:
if i not in indices:
first_indices.remove(i)
#raise ValueError("index %s not found or not a free index" % i)
first_indices.extend([i for i in indices if i not in first_indices])
permutation = [first_indices.index(i) for i in indices]
return CodegenArrayPermuteDims(result, permutation)
def _has_multiple_lines(expr):
if isinstance(expr, _RecognizeMatMulLines):
return True
if isinstance(expr, _RecognizeMatOp):
return expr.multiple_lines
return False
class _RecognizeMatOp(object):
"""
Class to help parsing matrix multiplication lines.
"""
def __init__(self, operator, args):
self.operator = operator
self.args = args
if any(_has_multiple_lines(arg) for arg in args):
multiple_lines = True
else:
multiple_lines = False
self.multiple_lines = multiple_lines
def rank(self):
if self.operator == Trace:
return 0
# TODO: check
return 2
def __repr__(self):
op = self.operator
if op == MatMul:
s = "*"
elif op == MatAdd:
s = "+"
else:
s = op.__name__
return "_RecognizeMatOp(%s, %s)" % (s, repr(self.args))
return "_RecognizeMatOp(%s)" % (s.join(repr(i) for i in self.args))
def __eq__(self, other):
if not isinstance(other, type(self)):
return False
if self.operator != other.operator:
return False
if self.args != other.args:
return False
return True
def __iter__(self):
return iter(self.args)
class _RecognizeMatMulLines(list):
"""
This class handles multiple parsed multiplication lines.
"""
def __new__(cls, args):
if len(args) == 1:
return args[0]
return list.__new__(cls, args)
def rank(self):
return reduce(lambda x, y: x*y, [get_rank(i) for i in self], S.One)
def __repr__(self):
return "_RecognizeMatMulLines(%s)" % super(_RecognizeMatMulLines, self).__repr__()
def _support_function_tp1_recognize(contraction_indices, args):
if not isinstance(args, list):
args = [args]
subranks = [get_rank(i) for i in args]
coeff = reduce(lambda x, y: x*y, [arg for arg, srank in zip(args, subranks) if srank == 0], S.One)
mapping = _get_mapping_from_subranks(subranks)
dlinks = _get_contraction_links(subranks, *contraction_indices)
flatten_contractions = [j for i in contraction_indices for j in i]
total_rank = sum(subranks)
# TODO: turn `free_indices` into a list?
free_indices = {i: i for i in range(total_rank) if i not in flatten_contractions}
return_list = []
while dlinks:
if free_indices:
first_index, starting_argind = min(free_indices.items(), key=lambda x: x[1])
free_indices.pop(first_index)
starting_argind, starting_pos = mapping[starting_argind]
else:
# Maybe a Trace
first_index = None
starting_argind = min(dlinks)
starting_pos = 0
current_argind, current_pos = starting_argind, starting_pos
matmul_args = []
prev_argind = None
prev_pos = None
last_index = None
while True:
elem = args[current_argind]
if current_pos == 1:
elem = _RecognizeMatOp(Transpose, [elem])
matmul_args.append(elem)
if current_argind not in dlinks:
break
other_pos = 1 - current_pos
link_dict = dlinks.pop(current_argind)
if other_pos not in link_dict:
if free_indices:
last_index = [i for i, j in free_indices.items() if mapping[j] == (current_argind, other_pos)][0]
else:
last_index = None
break
if len(link_dict) > 2:
raise NotImplementedError("not a matrix multiplication line")
prev_argind = current_argind
prev_pos = current_pos
# Get the last element of `link_dict` as the next link. The last
# element is the correct start for trace expressions:
current_argind, current_pos = link_dict[other_pos]
if current_argind == starting_argind:
# This is a trace:
if len(matmul_args) > 1:
matmul_args = [_RecognizeMatOp(Trace, [_RecognizeMatOp(MatMul, matmul_args)])]
else:
matmul_args = [_RecognizeMatOp(Trace, matmul_args)]
break
dlinks.pop(starting_argind, None)
free_indices.pop(last_index, None)
return_list.append(_RecognizeMatOp(MatMul, matmul_args))
if coeff != 1:
# Let's inject the coefficient:
return_list[0].args.insert(0, coeff)
return _RecognizeMatMulLines(return_list)
def recognize_matrix_expression(expr):
r"""
Recognize matrix expressions in codegen objects.
If more than one matrix multiplication line have been detected, return a
list with the matrix expressions.
Examples
========
>>> from sympy import MatrixSymbol, MatrixExpr, Sum, Symbol
>>> from sympy.abc import i, j, k, l, N
>>> from sympy.codegen.array_utils import CodegenArrayContraction, CodegenArrayTensorProduct
>>> from sympy.codegen.array_utils import recognize_matrix_expression, parse_indexed_expression
>>> A = MatrixSymbol("A", N, N)
>>> B = MatrixSymbol("B", N, N)
>>> C = MatrixSymbol("C", N, N)
>>> D = MatrixSymbol("D", N, N)
>>> expr = Sum(A[i, j]*B[j, k], (j, 0, N-1))
>>> cg = parse_indexed_expression(expr)
>>> recognize_matrix_expression(cg)
A*B
>>> cg = parse_indexed_expression(expr, first_indices=[k])
>>> recognize_matrix_expression(cg)
(A*B).T
Transposition is detected:
>>> expr = Sum(A[j, i]*B[j, k], (j, 0, N-1))
>>> cg = parse_indexed_expression(expr)
>>> recognize_matrix_expression(cg)
A.T*B
>>> cg = parse_indexed_expression(expr, first_indices=[k])
>>> recognize_matrix_expression(cg)
(A.T*B).T
Detect the trace:
>>> expr = Sum(A[i, i], (i, 0, N-1))
>>> cg = parse_indexed_expression(expr)
>>> recognize_matrix_expression(cg)
Trace(A)
Recognize some more complex traces:
>>> expr = Sum(A[i, j]*B[j, i], (i, 0, N-1), (j, 0, N-1))
>>> cg = parse_indexed_expression(expr)
>>> recognize_matrix_expression(cg)
Trace(A*B)
More complicated expressions:
>>> expr = Sum(A[i, j]*B[k, j]*A[l, k], (j, 0, N-1), (k, 0, N-1))
>>> cg = parse_indexed_expression(expr)
>>> recognize_matrix_expression(cg)
A*B.T*A.T
Expressions constructed from matrix expressions do not contain literal
indices, the positions of free indices are returned instead:
>>> expr = A*B
>>> cg = CodegenArrayContraction.from_MatMul(expr)
>>> recognize_matrix_expression(cg)
A*B
If more than one line of matrix multiplications is detected, return
separate matrix multiplication factors:
>>> cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, B, C, D), (1, 2), (5, 6))
>>> recognize_matrix_expression(cg)
[A*B, C*D]
The two lines have free indices at axes 0, 3 and 4, 7, respectively.
"""
# TODO: expr has to be a CodegenArray... type
rec = _recognize_matrix_expression(expr)
return _unfold_recognized_expr(rec)
def _recognize_matrix_expression(expr):
if isinstance(expr, CodegenArrayContraction):
args = _recognize_matrix_expression(expr.expr)
contraction_indices = expr.contraction_indices
if isinstance(args, _RecognizeMatOp) and args.operator == MatAdd:
addends = []
for arg in args.args:
addends.append(_support_function_tp1_recognize(contraction_indices, arg))
return _RecognizeMatOp(MatAdd, addends)
elif isinstance(args, _RecognizeMatMulLines):
return _support_function_tp1_recognize(contraction_indices, args)
return _support_function_tp1_recognize(contraction_indices, [args])
elif isinstance(expr, CodegenArrayElementwiseAdd):
add_args = []
for arg in expr.args:
add_args.append(_recognize_matrix_expression(arg))
return _RecognizeMatOp(MatAdd, add_args)
elif isinstance(expr, (MatrixSymbol, IndexedBase)):
return expr
elif isinstance(expr, CodegenArrayPermuteDims):
if expr.permutation.args[0] == [1, 0]:
return _RecognizeMatOp(Transpose, [_recognize_matrix_expression(expr.expr)])
elif isinstance(expr.expr, CodegenArrayTensorProduct):
ranks = expr.expr.subranks
intrange = list(range(sum(ranks)))
newrange = [expr.permutation(i) for i in range(sum(ranks))]
newpos = []
counter = 0
for rank in ranks:
newpos.append(newrange[counter:counter+rank])
counter += rank
newargs = []
for pos, arg in zip(newpos, expr.expr.args):
if pos == sorted(pos):
newargs.append((_recognize_matrix_expression(arg), pos[0]))
elif len(pos) == 2:
newargs.append((_RecognizeMatOp(Transpose, [_recognize_matrix_expression(arg)]), pos[0]))
else:
raise NotImplementedError
newargs.sort(key=lambda x: x[1])
newargs = [i[0] for i in newargs]
return _RecognizeMatMulLines(newargs)
else:
raise NotImplementedError
elif isinstance(expr, CodegenArrayTensorProduct):
args = [_recognize_matrix_expression(arg) for arg in expr.args]
multiple_lines = [_has_multiple_lines(arg) for arg in args]
if any(multiple_lines):
if any(a.operator != MatAdd for i, a in enumerate(args) if multiple_lines[i]):
raise NotImplementedError
expand_args = [arg.args if multiple_lines[i] else [arg] for i, arg in enumerate(args)]
it = itertools.product(*expand_args)
ret = _RecognizeMatOp(MatAdd, [_RecognizeMatMulLines([k for j in i for k in (j if isinstance(j, _RecognizeMatMulLines) else [j])]) for i in it])
return ret
return _RecognizeMatMulLines(args)
elif isinstance(expr, Transpose):
return expr
elif isinstance(expr, MatrixExpr):
return expr
return expr
def _unfold_recognized_expr(expr):
if isinstance(expr, _RecognizeMatOp):
return expr.operator(*[_unfold_recognized_expr(i) for i in expr.args])
elif isinstance(expr, _RecognizeMatMulLines):
return [_unfold_recognized_expr(i) for i in expr]
else:
return expr
|
65d22aeb0f36bf38487fee8000312dfdb8b9aa9c235228b1b432591f09cd0b0a
|
r"""
This module contains :py:meth:`~sympy.solvers.ode.dsolve` and different helper
functions that it uses.
:py:meth:`~sympy.solvers.ode.dsolve` solves ordinary differential equations.
See the docstring on the various functions for their uses. Note that partial
differential equations support is in ``pde.py``. Note that hint functions
have docstrings describing their various methods, but they are intended for
internal use. Use ``dsolve(ode, func, hint=hint)`` to solve an ODE using a
specific hint. See also the docstring on
:py:meth:`~sympy.solvers.ode.dsolve`.
**Functions in this module**
These are the user functions in this module:
- :py:meth:`~sympy.solvers.ode.dsolve` - Solves ODEs.
- :py:meth:`~sympy.solvers.ode.classify_ode` - Classifies ODEs into
possible hints for :py:meth:`~sympy.solvers.ode.dsolve`.
- :py:meth:`~sympy.solvers.ode.checkodesol` - Checks if an equation is the
solution to an ODE.
- :py:meth:`~sympy.solvers.ode.homogeneous_order` - Returns the
homogeneous order of an expression.
- :py:meth:`~sympy.solvers.ode.infinitesimals` - Returns the infinitesimals
of the Lie group of point transformations of an ODE, such that it is
invariant.
- :py:meth:`~sympy.solvers.ode_checkinfsol` - Checks if the given infinitesimals
are the actual infinitesimals of a first order ODE.
These are the non-solver helper functions that are for internal use. The
user should use the various options to
:py:meth:`~sympy.solvers.ode.dsolve` to obtain the functionality provided
by these functions:
- :py:meth:`~sympy.solvers.ode.odesimp` - Does all forms of ODE
simplification.
- :py:meth:`~sympy.solvers.ode.ode_sol_simplicity` - A key function for
comparing solutions by simplicity.
- :py:meth:`~sympy.solvers.ode.constantsimp` - Simplifies arbitrary
constants.
- :py:meth:`~sympy.solvers.ode.constant_renumber` - Renumber arbitrary
constants.
- :py:meth:`~sympy.solvers.ode._handle_Integral` - Evaluate unevaluated
Integrals.
See also the docstrings of these functions.
**Currently implemented solver methods**
The following methods are implemented for solving ordinary differential
equations. See the docstrings of the various hint functions for more
information on each (run ``help(ode)``):
- 1st order separable differential equations.
- 1st order differential equations whose coefficients or `dx` and `dy` are
functions homogeneous of the same order.
- 1st order exact differential equations.
- 1st order linear differential equations.
- 1st order Bernoulli differential equations.
- Power series solutions for first order differential equations.
- Lie Group method of solving first order differential equations.
- 2nd order Liouville differential equations.
- Power series solutions for second order differential equations
at ordinary and regular singular points.
- `n`\th order differential equation that can be solved with algebraic
rearrangement and integration.
- `n`\th order linear homogeneous differential equation with constant
coefficients.
- `n`\th order linear inhomogeneous differential equation with constant
coefficients using the method of undetermined coefficients.
- `n`\th order linear inhomogeneous differential equation with constant
coefficients using the method of variation of parameters.
**Philosophy behind this module**
This module is designed to make it easy to add new ODE solving methods without
having to mess with the solving code for other methods. The idea is that
there is a :py:meth:`~sympy.solvers.ode.classify_ode` function, which takes in
an ODE and tells you what hints, if any, will solve the ODE. It does this
without attempting to solve the ODE, so it is fast. Each solving method is a
hint, and it has its own function, named ``ode_<hint>``. That function takes
in the ODE and any match expression gathered by
:py:meth:`~sympy.solvers.ode.classify_ode` and returns a solved result. If
this result has any integrals in it, the hint function will return an
unevaluated :py:class:`~sympy.integrals.Integral` class.
:py:meth:`~sympy.solvers.ode.dsolve`, which is the user wrapper function
around all of this, will then call :py:meth:`~sympy.solvers.ode.odesimp` on
the result, which, among other things, will attempt to solve the equation for
the dependent variable (the function we are solving for), simplify the
arbitrary constants in the expression, and evaluate any integrals, if the hint
allows it.
**How to add new solution methods**
If you have an ODE that you want :py:meth:`~sympy.solvers.ode.dsolve` to be
able to solve, try to avoid adding special case code here. Instead, try
finding a general method that will solve your ODE, as well as others. This
way, the :py:mod:`~sympy.solvers.ode` module will become more robust, and
unhindered by special case hacks. WolphramAlpha and Maple's
DETools[odeadvisor] function are two resources you can use to classify a
specific ODE. It is also better for a method to work with an `n`\th order ODE
instead of only with specific orders, if possible.
To add a new method, there are a few things that you need to do. First, you
need a hint name for your method. Try to name your hint so that it is
unambiguous with all other methods, including ones that may not be implemented
yet. If your method uses integrals, also include a ``hint_Integral`` hint.
If there is more than one way to solve ODEs with your method, include a hint
for each one, as well as a ``<hint>_best`` hint. Your ``ode_<hint>_best()``
function should choose the best using min with ``ode_sol_simplicity`` as the
key argument. See
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_best`, for example.
The function that uses your method will be called ``ode_<hint>()``, so the
hint must only use characters that are allowed in a Python function name
(alphanumeric characters and the underscore '``_``' character). Include a
function for every hint, except for ``_Integral`` hints
(:py:meth:`~sympy.solvers.ode.dsolve` takes care of those automatically).
Hint names should be all lowercase, unless a word is commonly capitalized
(such as Integral or Bernoulli). If you have a hint that you do not want to
run with ``all_Integral`` that doesn't have an ``_Integral`` counterpart (such
as a best hint that would defeat the purpose of ``all_Integral``), you will
need to remove it manually in the :py:meth:`~sympy.solvers.ode.dsolve` code.
See also the :py:meth:`~sympy.solvers.ode.classify_ode` docstring for
guidelines on writing a hint name.
Determine *in general* how the solutions returned by your method compare with
other methods that can potentially solve the same ODEs. Then, put your hints
in the :py:data:`~sympy.solvers.ode.allhints` tuple in the order that they
should be called. The ordering of this tuple determines which hints are
default. Note that exceptions are ok, because it is easy for the user to
choose individual hints with :py:meth:`~sympy.solvers.ode.dsolve`. In
general, ``_Integral`` variants should go at the end of the list, and
``_best`` variants should go before the various hints they apply to. For
example, the ``undetermined_coefficients`` hint comes before the
``variation_of_parameters`` hint because, even though variation of parameters
is more general than undetermined coefficients, undetermined coefficients
generally returns cleaner results for the ODEs that it can solve than
variation of parameters does, and it does not require integration, so it is
much faster.
Next, you need to have a match expression or a function that matches the type
of the ODE, which you should put in :py:meth:`~sympy.solvers.ode.classify_ode`
(if the match function is more than just a few lines, like
:py:meth:`~sympy.solvers.ode._undetermined_coefficients_match`, it should go
outside of :py:meth:`~sympy.solvers.ode.classify_ode`). It should match the
ODE without solving for it as much as possible, so that
:py:meth:`~sympy.solvers.ode.classify_ode` remains fast and is not hindered by
bugs in solving code. Be sure to consider corner cases. For example, if your
solution method involves dividing by something, make sure you exclude the case
where that division will be 0.
In most cases, the matching of the ODE will also give you the various parts
that you need to solve it. You should put that in a dictionary (``.match()``
will do this for you), and add that as ``matching_hints['hint'] = matchdict``
in the relevant part of :py:meth:`~sympy.solvers.ode.classify_ode`.
:py:meth:`~sympy.solvers.ode.classify_ode` will then send this to
:py:meth:`~sympy.solvers.ode.dsolve`, which will send it to your function as
the ``match`` argument. Your function should be named ``ode_<hint>(eq, func,
order, match)`. If you need to send more information, put it in the ``match``
dictionary. For example, if you had to substitute in a dummy variable in
:py:meth:`~sympy.solvers.ode.classify_ode` to match the ODE, you will need to
pass it to your function using the `match` dict to access it. You can access
the independent variable using ``func.args[0]``, and the dependent variable
(the function you are trying to solve for) as ``func.func``. If, while trying
to solve the ODE, you find that you cannot, raise ``NotImplementedError``.
:py:meth:`~sympy.solvers.ode.dsolve` will catch this error with the ``all``
meta-hint, rather than causing the whole routine to fail.
Add a docstring to your function that describes the method employed. Like
with anything else in SymPy, you will need to add a doctest to the docstring,
in addition to real tests in ``test_ode.py``. Try to maintain consistency
with the other hint functions' docstrings. Add your method to the list at the
top of this docstring. Also, add your method to ``ode.rst`` in the
``docs/src`` directory, so that the Sphinx docs will pull its docstring into
the main SymPy documentation. Be sure to make the Sphinx documentation by
running ``make html`` from within the doc directory to verify that the
docstring formats correctly.
If your solution method involves integrating, use :py:meth:`Integral()
<sympy.integrals.integrals.Integral>` instead of
:py:meth:`~sympy.core.expr.Expr.integrate`. This allows the user to bypass
hard/slow integration by using the ``_Integral`` variant of your hint. In
most cases, calling :py:meth:`sympy.core.basic.Basic.doit` will integrate your
solution. If this is not the case, you will need to write special code in
:py:meth:`~sympy.solvers.ode._handle_Integral`. Arbitrary constants should be
symbols named ``C1``, ``C2``, and so on. All solution methods should return
an equality instance. If you need an arbitrary number of arbitrary constants,
you can use ``constants = numbered_symbols(prefix='C', cls=Symbol, start=1)``.
If it is possible to solve for the dependent function in a general way, do so.
Otherwise, do as best as you can, but do not call solve in your
``ode_<hint>()`` function. :py:meth:`~sympy.solvers.ode.odesimp` will attempt
to solve the solution for you, so you do not need to do that. Lastly, if your
ODE has a common simplification that can be applied to your solutions, you can
add a special case in :py:meth:`~sympy.solvers.ode.odesimp` for it. For
example, solutions returned from the ``1st_homogeneous_coeff`` hints often
have many :py:meth:`~sympy.functions.log` terms, so
:py:meth:`~sympy.solvers.ode.odesimp` calls
:py:meth:`~sympy.simplify.simplify.logcombine` on them (it also helps to write
the arbitrary constant as ``log(C1)`` instead of ``C1`` in this case). Also
consider common ways that you can rearrange your solution to have
:py:meth:`~sympy.solvers.ode.constantsimp` take better advantage of it. It is
better to put simplification in :py:meth:`~sympy.solvers.ode.odesimp` than in
your method, because it can then be turned off with the simplify flag in
:py:meth:`~sympy.solvers.ode.dsolve`. If you have any extraneous
simplification in your function, be sure to only run it using ``if
match.get('simplify', True):``, especially if it can be slow or if it can
reduce the domain of the solution.
Finally, as with every contribution to SymPy, your method will need to be
tested. Add a test for each method in ``test_ode.py``. Follow the
conventions there, i.e., test the solver using ``dsolve(eq, f(x),
hint=your_hint)``, and also test the solution using
:py:meth:`~sympy.solvers.ode.checkodesol` (you can put these in a separate
tests and skip/XFAIL if it runs too slow/doesn't work). Be sure to call your
hint specifically in :py:meth:`~sympy.solvers.ode.dsolve`, that way the test
won't be broken simply by the introduction of another matching hint. If your
method works for higher order (>1) ODEs, you will need to run ``sol =
constant_renumber(sol, 'C', 1, order)`` for each solution, where ``order`` is
the order of the ODE. This is because ``constant_renumber`` renumbers the
arbitrary constants by printing order, which is platform dependent. Try to
test every corner case of your solver, including a range of orders if it is a
`n`\th order solver, but if your solver is slow, such as if it involves hard
integration, try to keep the test run time down.
Feel free to refactor existing hints to avoid duplicating code or creating
inconsistencies. If you can show that your method exactly duplicates an
existing method, including in the simplicity and speed of obtaining the
solutions, then you can remove the old, less general method. The existing
code is tested extensively in ``test_ode.py``, so if anything is broken, one
of those tests will surely fail.
"""
from __future__ import print_function, division
from collections import defaultdict
from itertools import islice
from functools import cmp_to_key
from sympy.core import Add, S, Mul, Pow, oo
from sympy.core.compatibility import ordered, iterable, is_sequence, range
from sympy.core.containers import Tuple
from sympy.core.exprtools import factor_terms
from sympy.core.expr import AtomicExpr, Expr
from sympy.core.function import (Function, Derivative, AppliedUndef, diff,
expand, expand_mul, Subs, _mexpand)
from sympy.core.multidimensional import vectorize
from sympy.core.numbers import NaN, zoo, I, Number
from sympy.core.relational import Equality, Eq
from sympy.core.symbol import Symbol, Wild, Dummy, symbols
from sympy.core.sympify import sympify
from sympy.logic.boolalg import (BooleanAtom, And, Or, Not, BooleanTrue,
BooleanFalse)
from sympy.functions import cos, exp, im, log, re, sin, tan, sqrt, \
atan2, conjugate, Piecewise
from sympy.functions.combinatorial.factorials import factorial
from sympy.integrals.integrals import Integral, integrate
from sympy.matrices import wronskian, Matrix, eye, zeros
from sympy.polys import (Poly, RootOf, rootof, terms_gcd,
PolynomialError, lcm, roots)
from sympy.polys.polyroots import roots_quartic
from sympy.polys.polytools import cancel, degree, div
from sympy.series import Order
from sympy.series.series import series
from sympy.simplify import collect, logcombine, powsimp, separatevars, \
simplify, trigsimp, denom, posify, cse
from sympy.simplify.powsimp import powdenest
from sympy.simplify.radsimp import collect_const
from sympy.solvers import solve
from sympy.solvers.pde import pdsolve
from sympy.utilities import numbered_symbols, default_sort_key, sift
from sympy.solvers.deutils import _preprocess, ode_order, _desolve
#: This is a list of hints in the order that they should be preferred by
#: :py:meth:`~sympy.solvers.ode.classify_ode`. In general, hints earlier in the
#: list should produce simpler solutions than those later in the list (for
#: ODEs that fit both). For now, the order of this list is based on empirical
#: observations by the developers of SymPy.
#:
#: The hint used by :py:meth:`~sympy.solvers.ode.dsolve` for a specific ODE
#: can be overridden (see the docstring).
#:
#: In general, ``_Integral`` hints are grouped at the end of the list, unless
#: there is a method that returns an unevaluable integral most of the time
#: (which go near the end of the list anyway). ``default``, ``all``,
#: ``best``, and ``all_Integral`` meta-hints should not be included in this
#: list, but ``_best`` and ``_Integral`` hints should be included.
allhints = (
"nth_algebraic",
"separable",
"1st_exact",
"1st_linear",
"Bernoulli",
"Riccati_special_minus2",
"1st_homogeneous_coeff_best",
"1st_homogeneous_coeff_subs_indep_div_dep",
"1st_homogeneous_coeff_subs_dep_div_indep",
"almost_linear",
"linear_coefficients",
"separable_reduced",
"1st_power_series",
"lie_group",
"nth_linear_constant_coeff_homogeneous",
"nth_linear_euler_eq_homogeneous",
"nth_linear_constant_coeff_undetermined_coefficients",
"nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients",
"nth_linear_constant_coeff_variation_of_parameters",
"nth_linear_euler_eq_nonhomogeneous_variation_of_parameters",
"Liouville",
"2nd_power_series_ordinary",
"2nd_power_series_regular",
"nth_algebraic_Integral",
"separable_Integral",
"1st_exact_Integral",
"1st_linear_Integral",
"Bernoulli_Integral",
"1st_homogeneous_coeff_subs_indep_div_dep_Integral",
"1st_homogeneous_coeff_subs_dep_div_indep_Integral",
"almost_linear_Integral",
"linear_coefficients_Integral",
"separable_reduced_Integral",
"nth_linear_constant_coeff_variation_of_parameters_Integral",
"nth_linear_euler_eq_nonhomogeneous_variation_of_parameters_Integral",
"Liouville_Integral",
)
lie_heuristics = (
"abaco1_simple",
"abaco1_product",
"abaco2_similar",
"abaco2_unique_unknown",
"abaco2_unique_general",
"linear",
"function_sum",
"bivariate",
"chi"
)
def sub_func_doit(eq, func, new):
r"""
When replacing the func with something else, we usually want the
derivative evaluated, so this function helps in making that happen.
To keep subs from having to look through all derivatives, we mask them off
with dummy variables, do the func sub, and then replace masked-off
derivatives with their doit values.
Examples
========
>>> from sympy import Derivative, symbols, Function
>>> from sympy.solvers.ode import sub_func_doit
>>> x, z = symbols('x, z')
>>> y = Function('y')
>>> sub_func_doit(3*Derivative(y(x), x) - 1, y(x), x)
2
>>> sub_func_doit(x*Derivative(y(x), x) - y(x)**2 + y(x), y(x),
... 1/(x*(z + 1/x)))
x*(-1/(x**2*(z + 1/x)) + 1/(x**3*(z + 1/x)**2)) + 1/(x*(z + 1/x))
...- 1/(x**2*(z + 1/x)**2)
"""
reps = {}
repu = {}
for d in eq.atoms(Derivative):
u = Dummy('u')
repu[u] = d.subs(func, new).doit()
reps[d] = u
# Make sure that expressions such as ``Derivative(f(x), (x, 2))`` get
# replaced before ``Derivative(f(x), x)``:
#
# Also replace e.g. Derivative(x*Derivative(f(x), x), x) before
# Derivative(f(x), x)
def cmp(subs1, subs2):
return subs2[0].has(subs1[0]) - subs1[0].has(subs2[0])
key = lambda x: (-x[0].derivative_count, cmp_to_key(cmp)(x))
reps = sorted(reps.items(), key=key)
return eq.subs(reps).subs(func, new).subs(repu)
def get_numbered_constants(eq, num=1, start=1, prefix='C'):
"""
Returns a list of constants that do not occur
in eq already.
"""
if isinstance(eq, Expr):
eq = [eq]
elif not iterable(eq):
raise ValueError("Expected Expr or iterable but got %s" % eq)
atom_set = set().union(*[i.free_symbols for i in eq])
func_set = set().union(*[i.atoms(Function) for i in eq])
if func_set:
atom_set |= {Symbol(str(f.func)) for f in func_set}
ncs = numbered_symbols(start=start, prefix=prefix, exclude=atom_set)
Cs = [next(ncs) for i in range(num)]
return (Cs[0] if num == 1 else tuple(Cs))
def dsolve(eq, func=None, hint="default", simplify=True,
ics= None, xi=None, eta=None, x0=0, n=6, **kwargs):
r"""
Solves any (supported) kind of ordinary differential equation and
system of ordinary differential equations.
For single ordinary differential equation
=========================================
It is classified under this when number of equation in ``eq`` is one.
**Usage**
``dsolve(eq, f(x), hint)`` -> Solve ordinary differential equation
``eq`` for function ``f(x)``, using method ``hint``.
**Details**
``eq`` can be any supported ordinary differential equation (see the
:py:mod:`~sympy.solvers.ode` docstring for supported methods).
This can either be an :py:class:`~sympy.core.relational.Equality`,
or an expression, which is assumed to be equal to ``0``.
``f(x)`` is a function of one variable whose derivatives in that
variable make up the ordinary differential equation ``eq``. In
many cases it is not necessary to provide this; it will be
autodetected (and an error raised if it couldn't be detected).
``hint`` is the solving method that you want dsolve to use. Use
``classify_ode(eq, f(x))`` to get all of the possible hints for an
ODE. The default hint, ``default``, will use whatever hint is
returned first by :py:meth:`~sympy.solvers.ode.classify_ode`. See
Hints below for more options that you can use for hint.
``simplify`` enables simplification by
:py:meth:`~sympy.solvers.ode.odesimp`. See its docstring for more
information. Turn this off, for example, to disable solving of
solutions for ``func`` or simplification of arbitrary constants.
It will still integrate with this hint. Note that the solution may
contain more arbitrary constants than the order of the ODE with
this option enabled.
``xi`` and ``eta`` are the infinitesimal functions of an ordinary
differential equation. They are the infinitesimals of the Lie group
of point transformations for which the differential equation is
invariant. The user can specify values for the infinitesimals. If
nothing is specified, ``xi`` and ``eta`` are calculated using
:py:meth:`~sympy.solvers.ode.infinitesimals` with the help of various
heuristics.
``ics`` is the set of initial/boundary conditions for the differential equation.
It should be given in the form of ``{f(x0): x1, f(x).diff(x).subs(x, x2):
x3}`` and so on. For power series solutions, if no initial
conditions are specified ``f(0)`` is assumed to be ``C0`` and the power
series solution is calculated about 0.
``x0`` is the point about which the power series solution of a differential
equation is to be evaluated.
``n`` gives the exponent of the dependent variable up to which the power series
solution of a differential equation is to be evaluated.
**Hints**
Aside from the various solving methods, there are also some meta-hints
that you can pass to :py:meth:`~sympy.solvers.ode.dsolve`:
``default``:
This uses whatever hint is returned first by
:py:meth:`~sympy.solvers.ode.classify_ode`. This is the
default argument to :py:meth:`~sympy.solvers.ode.dsolve`.
``all``:
To make :py:meth:`~sympy.solvers.ode.dsolve` apply all
relevant classification hints, use ``dsolve(ODE, func,
hint="all")``. This will return a dictionary of
``hint:solution`` terms. If a hint causes dsolve to raise the
``NotImplementedError``, value of that hint's key will be the
exception object raised. The dictionary will also include
some special keys:
- ``order``: The order of the ODE. See also
:py:meth:`~sympy.solvers.deutils.ode_order` in
``deutils.py``.
- ``best``: The simplest hint; what would be returned by
``best`` below.
- ``best_hint``: The hint that would produce the solution
given by ``best``. If more than one hint produces the best
solution, the first one in the tuple returned by
:py:meth:`~sympy.solvers.ode.classify_ode` is chosen.
- ``default``: The solution that would be returned by default.
This is the one produced by the hint that appears first in
the tuple returned by
:py:meth:`~sympy.solvers.ode.classify_ode`.
``all_Integral``:
This is the same as ``all``, except if a hint also has a
corresponding ``_Integral`` hint, it only returns the
``_Integral`` hint. This is useful if ``all`` causes
:py:meth:`~sympy.solvers.ode.dsolve` to hang because of a
difficult or impossible integral. This meta-hint will also be
much faster than ``all``, because
:py:meth:`~sympy.core.expr.Expr.integrate` is an expensive
routine.
``best``:
To have :py:meth:`~sympy.solvers.ode.dsolve` try all methods
and return the simplest one. This takes into account whether
the solution is solvable in the function, whether it contains
any Integral classes (i.e. unevaluatable integrals), and
which one is the shortest in size.
See also the :py:meth:`~sympy.solvers.ode.classify_ode` docstring for
more info on hints, and the :py:mod:`~sympy.solvers.ode` docstring for
a list of all supported hints.
**Tips**
- You can declare the derivative of an unknown function this way:
>>> from sympy import Function, Derivative
>>> from sympy.abc import x # x is the independent variable
>>> f = Function("f")(x) # f is a function of x
>>> # f_ will be the derivative of f with respect to x
>>> f_ = Derivative(f, x)
- See ``test_ode.py`` for many tests, which serves also as a set of
examples for how to use :py:meth:`~sympy.solvers.ode.dsolve`.
- :py:meth:`~sympy.solvers.ode.dsolve` always returns an
:py:class:`~sympy.core.relational.Equality` class (except for the
case when the hint is ``all`` or ``all_Integral``). If possible, it
solves the solution explicitly for the function being solved for.
Otherwise, it returns an implicit solution.
- Arbitrary constants are symbols named ``C1``, ``C2``, and so on.
- Because all solutions should be mathematically equivalent, some
hints may return the exact same result for an ODE. Often, though,
two different hints will return the same solution formatted
differently. The two should be equivalent. Also note that sometimes
the values of the arbitrary constants in two different solutions may
not be the same, because one constant may have "absorbed" other
constants into it.
- Do ``help(ode.ode_<hintname>)`` to get help more information on a
specific hint, where ``<hintname>`` is the name of a hint without
``_Integral``.
For system of ordinary differential equations
=============================================
**Usage**
``dsolve(eq, func)`` -> Solve a system of ordinary differential
equations ``eq`` for ``func`` being list of functions including
`x(t)`, `y(t)`, `z(t)` where number of functions in the list depends
upon the number of equations provided in ``eq``.
**Details**
``eq`` can be any supported system of ordinary differential equations
This can either be an :py:class:`~sympy.core.relational.Equality`,
or an expression, which is assumed to be equal to ``0``.
``func`` holds ``x(t)`` and ``y(t)`` being functions of one variable which
together with some of their derivatives make up the system of ordinary
differential equation ``eq``. It is not necessary to provide this; it
will be autodetected (and an error raised if it couldn't be detected).
**Hints**
The hints are formed by parameters returned by classify_sysode, combining
them give hints name used later for forming method name.
Examples
========
>>> from sympy import Function, dsolve, Eq, Derivative, sin, cos, symbols
>>> from sympy.abc import x
>>> f = Function('f')
>>> dsolve(Derivative(f(x), x, x) + 9*f(x), f(x))
Eq(f(x), C1*sin(3*x) + C2*cos(3*x))
>>> eq = sin(x)*cos(f(x)) + cos(x)*sin(f(x))*f(x).diff(x)
>>> dsolve(eq, hint='1st_exact')
[Eq(f(x), -acos(C1/cos(x)) + 2*pi), Eq(f(x), acos(C1/cos(x)))]
>>> dsolve(eq, hint='almost_linear')
[Eq(f(x), -acos(C1/cos(x)) + 2*pi), Eq(f(x), acos(C1/cos(x)))]
>>> t = symbols('t')
>>> x, y = symbols('x, y', cls=Function)
>>> eq = (Eq(Derivative(x(t),t), 12*t*x(t) + 8*y(t)), Eq(Derivative(y(t),t), 21*x(t) + 7*t*y(t)))
>>> dsolve(eq)
[Eq(x(t), C1*x0(t) + C2*x0(t)*Integral(8*exp(Integral(7*t, t))*exp(Integral(12*t, t))/x0(t)**2, t)),
Eq(y(t), C1*y0(t) + C2*(y0(t)*Integral(8*exp(Integral(7*t, t))*exp(Integral(12*t, t))/x0(t)**2, t) +
exp(Integral(7*t, t))*exp(Integral(12*t, t))/x0(t)))]
>>> eq = (Eq(Derivative(x(t),t),x(t)*y(t)*sin(t)), Eq(Derivative(y(t),t),y(t)**2*sin(t)))
>>> dsolve(eq)
{Eq(x(t), -exp(C1)/(C2*exp(C1) - cos(t))), Eq(y(t), -1/(C1 - cos(t)))}
"""
if iterable(eq):
match = classify_sysode(eq, func)
eq = match['eq']
order = match['order']
func = match['func']
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
# keep highest order term coefficient positive
for i in range(len(eq)):
for func_ in func:
if isinstance(func_, list):
pass
else:
if eq[i].coeff(diff(func[i],t,ode_order(eq[i], func[i]))).is_negative:
eq[i] = -eq[i]
match['eq'] = eq
if len(set(order.values()))!=1:
raise ValueError("It solves only those systems of equations whose orders are equal")
match['order'] = list(order.values())[0]
def recur_len(l):
return sum(recur_len(item) if isinstance(item,list) else 1 for item in l)
if recur_len(func) != len(eq):
raise ValueError("dsolve() and classify_sysode() work with "
"number of functions being equal to number of equations")
if match['type_of_equation'] is None:
raise NotImplementedError
else:
if match['is_linear'] == True:
if match['no_of_equation'] > 3:
solvefunc = globals()['sysode_linear_neq_order%(order)s' % match]
else:
solvefunc = globals()['sysode_linear_%(no_of_equation)seq_order%(order)s' % match]
else:
solvefunc = globals()['sysode_nonlinear_%(no_of_equation)seq_order%(order)s' % match]
sols = solvefunc(match)
if ics:
constants = Tuple(*sols).free_symbols - Tuple(*eq).free_symbols
solved_constants = solve_ics(sols, func, constants, ics)
return [sol.subs(solved_constants) for sol in sols]
return sols
else:
given_hint = hint # hint given by the user
# See the docstring of _desolve for more details.
hints = _desolve(eq, func=func,
hint=hint, simplify=True, xi=xi, eta=eta, type='ode', ics=ics,
x0=x0, n=n, **kwargs)
eq = hints.pop('eq', eq)
all_ = hints.pop('all', False)
if all_:
retdict = {}
failed_hints = {}
gethints = classify_ode(eq, dict=True)
orderedhints = gethints['ordered_hints']
for hint in hints:
try:
rv = _helper_simplify(eq, hint, hints[hint], simplify)
except NotImplementedError as detail:
failed_hints[hint] = detail
else:
retdict[hint] = rv
func = hints[hint]['func']
retdict['best'] = min(list(retdict.values()), key=lambda x:
ode_sol_simplicity(x, func, trysolving=not simplify))
if given_hint == 'best':
return retdict['best']
for i in orderedhints:
if retdict['best'] == retdict.get(i, None):
retdict['best_hint'] = i
break
retdict['default'] = gethints['default']
retdict['order'] = gethints['order']
retdict.update(failed_hints)
return retdict
else:
# The key 'hint' stores the hint needed to be solved for.
hint = hints['hint']
return _helper_simplify(eq, hint, hints, simplify, ics=ics)
def _helper_simplify(eq, hint, match, simplify=True, ics=None, **kwargs):
r"""
Helper function of dsolve that calls the respective
:py:mod:`~sympy.solvers.ode` functions to solve for the ordinary
differential equations. This minimizes the computation in calling
:py:meth:`~sympy.solvers.deutils._desolve` multiple times.
"""
r = match
if hint.endswith('_Integral'):
solvefunc = globals()['ode_' + hint[:-len('_Integral')]]
else:
solvefunc = globals()['ode_' + hint]
func = r['func']
order = r['order']
match = r[hint]
free = eq.free_symbols
cons = lambda s: s.free_symbols.difference(free)
if simplify:
# odesimp() will attempt to integrate, if necessary, apply constantsimp(),
# attempt to solve for func, and apply any other hint specific
# simplifications
sols = solvefunc(eq, func, order, match)
if isinstance(sols, Expr):
rv = odesimp(sols, func, order, cons(sols), hint)
else:
rv = [odesimp(s, func, order, cons(s), hint) for s in sols]
else:
# We still want to integrate (you can disable it separately with the hint)
match['simplify'] = False # Some hints can take advantage of this option
rv = _handle_Integral(solvefunc(eq, func, order, match),
func, order, hint)
if ics and not 'power_series' in hint:
if isinstance(rv, Expr):
solved_constants = solve_ics([rv], [r['func']], cons(rv), ics)
rv = rv.subs(solved_constants)
else:
rv1 = []
for s in rv:
solved_constants = solve_ics([s], [r['func']], cons(s), ics)
rv1.append(s.subs(solved_constants))
rv = rv1
return rv
def solve_ics(sols, funcs, constants, ics):
"""
Solve for the constants given initial conditions
``sols`` is a list of solutions.
``funcs`` is a list of functions.
``constants`` is a list of constants.
``ics`` is the set of initial/boundary conditions for the differential
equation. It should be given in the form of ``{f(x0): x1,
f(x).diff(x).subs(x, x2): x3}`` and so on.
Returns a dictionary mapping constants to values.
``solution.subs(constants)`` will replace the constants in ``solution``.
Example
=======
>>> # From dsolve(f(x).diff(x) - f(x), f(x))
>>> from sympy import symbols, Eq, exp, Function
>>> from sympy.solvers.ode import solve_ics
>>> f = Function('f')
>>> x, C1 = symbols('x C1')
>>> sols = [Eq(f(x), C1*exp(x))]
>>> funcs = [f(x)]
>>> constants = [C1]
>>> ics = {f(0): 2}
>>> solved_constants = solve_ics(sols, funcs, constants, ics)
>>> solved_constants
{C1: 2}
>>> sols[0].subs(solved_constants)
Eq(f(x), 2*exp(x))
"""
# Assume ics are of the form f(x0): value or Subs(diff(f(x), x, n), (x,
# x0)): value (currently checked by classify_ode). To solve, replace x
# with x0, f(x0) with value, then solve for constants. For f^(n)(x0),
# differentiate the solution n times, so that f^(n)(x) appears.
x = funcs[0].args[0]
diff_sols = []
subs_sols = []
diff_variables = set()
for funcarg, value in ics.items():
if isinstance(funcarg, AppliedUndef):
x0 = funcarg.args[0]
matching_func = [f for f in funcs if f.func == funcarg.func][0]
S = sols
elif isinstance(funcarg, (Subs, Derivative)):
if isinstance(funcarg, Subs):
# Make sure it stays a subs. Otherwise subs below will produce
# a different looking term.
funcarg = funcarg.doit()
if isinstance(funcarg, Subs):
deriv = funcarg.expr
x0 = funcarg.point[0]
variables = funcarg.expr.variables
matching_func = deriv
elif isinstance(funcarg, Derivative):
deriv = funcarg
x0 = funcarg.variables[0]
variables = (x,)*len(funcarg.variables)
matching_func = deriv.subs(x0, x)
if variables not in diff_variables:
for sol in sols:
if sol.has(deriv.expr.func):
diff_sols.append(Eq(sol.lhs.diff(*variables), sol.rhs.diff(*variables)))
diff_variables.add(variables)
S = diff_sols
else:
raise NotImplementedError("Unrecognized initial condition")
for sol in S:
if sol.has(matching_func):
sol2 = sol
sol2 = sol2.subs(x, x0)
sol2 = sol2.subs(funcarg, value)
subs_sols.append(sol2)
# TODO: Use solveset here
try:
solved_constants = solve(subs_sols, constants, dict=True)
except NotImplementedError:
solved_constants = []
# XXX: We can't differentiate between the solution not existing because of
# invalid initial conditions, and not existing because solve is not smart
# enough. If we could use solveset, this might be improvable, but for now,
# we use NotImplementedError in this case.
if not solved_constants:
raise NotImplementedError("Couldn't solve for initial conditions")
if solved_constants == True:
raise ValueError("Initial conditions did not produce any solutions for constants. Perhaps they are degenerate.")
if len(solved_constants) > 1:
raise NotImplementedError("Initial conditions produced too many solutions for constants")
if len(solved_constants[0]) != len(constants):
raise ValueError("Initial conditions did not produce a solution for all constants. Perhaps they are under-specified.")
return solved_constants[0]
def classify_ode(eq, func=None, dict=False, ics=None, **kwargs):
r"""
Returns a tuple of possible :py:meth:`~sympy.solvers.ode.dsolve`
classifications for an ODE.
The tuple is ordered so that first item is the classification that
:py:meth:`~sympy.solvers.ode.dsolve` uses to solve the ODE by default. In
general, classifications at the near the beginning of the list will
produce better solutions faster than those near the end, thought there are
always exceptions. To make :py:meth:`~sympy.solvers.ode.dsolve` use a
different classification, use ``dsolve(ODE, func,
hint=<classification>)``. See also the
:py:meth:`~sympy.solvers.ode.dsolve` docstring for different meta-hints
you can use.
If ``dict`` is true, :py:meth:`~sympy.solvers.ode.classify_ode` will
return a dictionary of ``hint:match`` expression terms. This is intended
for internal use by :py:meth:`~sympy.solvers.ode.dsolve`. Note that
because dictionaries are ordered arbitrarily, this will most likely not be
in the same order as the tuple.
You can get help on different hints by executing
``help(ode.ode_hintname)``, where ``hintname`` is the name of the hint
without ``_Integral``.
See :py:data:`~sympy.solvers.ode.allhints` or the
:py:mod:`~sympy.solvers.ode` docstring for a list of all supported hints
that can be returned from :py:meth:`~sympy.solvers.ode.classify_ode`.
Notes
=====
These are remarks on hint names.
``_Integral``
If a classification has ``_Integral`` at the end, it will return the
expression with an unevaluated :py:class:`~sympy.integrals.Integral`
class in it. Note that a hint may do this anyway if
:py:meth:`~sympy.core.expr.Expr.integrate` cannot do the integral,
though just using an ``_Integral`` will do so much faster. Indeed, an
``_Integral`` hint will always be faster than its corresponding hint
without ``_Integral`` because
:py:meth:`~sympy.core.expr.Expr.integrate` is an expensive routine.
If :py:meth:`~sympy.solvers.ode.dsolve` hangs, it is probably because
:py:meth:`~sympy.core.expr.Expr.integrate` is hanging on a tough or
impossible integral. Try using an ``_Integral`` hint or
``all_Integral`` to get it return something.
Note that some hints do not have ``_Integral`` counterparts. This is
because :py:meth:`~sympy.solvers.ode.integrate` is not used in solving
the ODE for those method. For example, `n`\th order linear homogeneous
ODEs with constant coefficients do not require integration to solve,
so there is no ``nth_linear_homogeneous_constant_coeff_Integrate``
hint. You can easily evaluate any unevaluated
:py:class:`~sympy.integrals.Integral`\s in an expression by doing
``expr.doit()``.
Ordinals
Some hints contain an ordinal such as ``1st_linear``. This is to help
differentiate them from other hints, as well as from other methods
that may not be implemented yet. If a hint has ``nth`` in it, such as
the ``nth_linear`` hints, this means that the method used to applies
to ODEs of any order.
``indep`` and ``dep``
Some hints contain the words ``indep`` or ``dep``. These reference
the independent variable and the dependent function, respectively. For
example, if an ODE is in terms of `f(x)`, then ``indep`` will refer to
`x` and ``dep`` will refer to `f`.
``subs``
If a hints has the word ``subs`` in it, it means the the ODE is solved
by substituting the expression given after the word ``subs`` for a
single dummy variable. This is usually in terms of ``indep`` and
``dep`` as above. The substituted expression will be written only in
characters allowed for names of Python objects, meaning operators will
be spelled out. For example, ``indep``/``dep`` will be written as
``indep_div_dep``.
``coeff``
The word ``coeff`` in a hint refers to the coefficients of something
in the ODE, usually of the derivative terms. See the docstring for
the individual methods for more info (``help(ode)``). This is
contrast to ``coefficients``, as in ``undetermined_coefficients``,
which refers to the common name of a method.
``_best``
Methods that have more than one fundamental way to solve will have a
hint for each sub-method and a ``_best`` meta-classification. This
will evaluate all hints and return the best, using the same
considerations as the normal ``best`` meta-hint.
Examples
========
>>> from sympy import Function, classify_ode, Eq
>>> from sympy.abc import x
>>> f = Function('f')
>>> classify_ode(Eq(f(x).diff(x), 0), f(x))
('nth_algebraic', 'separable', '1st_linear', '1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_dep_div_indep',
'1st_power_series', 'lie_group',
'nth_linear_constant_coeff_homogeneous',
'nth_linear_euler_eq_homogeneous', 'nth_algebraic_Integral',
'separable_Integral', '1st_linear_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral')
>>> classify_ode(f(x).diff(x, 2) + 3*f(x).diff(x) + 2*f(x) - 4)
('nth_linear_constant_coeff_undetermined_coefficients',
'nth_linear_constant_coeff_variation_of_parameters',
'nth_linear_constant_coeff_variation_of_parameters_Integral')
"""
ics = sympify(ics)
prep = kwargs.pop('prep', True)
if func and len(func.args) != 1:
raise ValueError("dsolve() and classify_ode() only "
"work with functions of one variable, not %s" % func)
if prep or func is None:
eq, func_ = _preprocess(eq, func)
if func is None:
func = func_
x = func.args[0]
f = func.func
y = Dummy('y')
xi = kwargs.get('xi')
eta = kwargs.get('eta')
terms = kwargs.get('n')
if isinstance(eq, Equality):
if eq.rhs != 0:
return classify_ode(eq.lhs - eq.rhs, func, dict=dict, ics=ics, xi=xi,
n=terms, eta=eta, prep=False)
eq = eq.lhs
order = ode_order(eq, f(x))
# hint:matchdict or hint:(tuple of matchdicts)
# Also will contain "default":<default hint> and "order":order items.
matching_hints = {"order": order}
if not order:
if dict:
matching_hints["default"] = None
return matching_hints
else:
return ()
df = f(x).diff(x)
a = Wild('a', exclude=[f(x)])
b = Wild('b', exclude=[f(x)])
c = Wild('c', exclude=[f(x)])
d = Wild('d', exclude=[df, f(x).diff(x, 2)])
e = Wild('e', exclude=[df])
k = Wild('k', exclude=[df])
n = Wild('n', exclude=[x, f(x), df])
c1 = Wild('c1', exclude=[x])
a2 = Wild('a2', exclude=[x, f(x), df])
b2 = Wild('b2', exclude=[x, f(x), df])
c2 = Wild('c2', exclude=[x, f(x), df])
d2 = Wild('d2', exclude=[x, f(x), df])
a3 = Wild('a3', exclude=[f(x), df, f(x).diff(x, 2)])
b3 = Wild('b3', exclude=[f(x), df, f(x).diff(x, 2)])
c3 = Wild('c3', exclude=[f(x), df, f(x).diff(x, 2)])
r3 = {'xi': xi, 'eta': eta} # Used for the lie_group hint
boundary = {} # Used to extract initial conditions
C1 = Symbol("C1")
eq = expand(eq)
# Preprocessing to get the initial conditions out
if ics is not None:
for funcarg in ics:
# Separating derivatives
if isinstance(funcarg, (Subs, Derivative)):
# f(x).diff(x).subs(x, 0) is a Subs, but f(x).diff(x).subs(x,
# y) is a Derivative
if isinstance(funcarg, Subs):
deriv = funcarg.expr
old = funcarg.variables[0]
new = funcarg.point[0]
elif isinstance(funcarg, Derivative):
deriv = funcarg
# No information on this. Just assume it was x
old = x
new = funcarg.variables[0]
if (isinstance(deriv, Derivative) and isinstance(deriv.args[0],
AppliedUndef) and deriv.args[0].func == f and
len(deriv.args[0].args) == 1 and old == x and not
new.has(x) and all(i == deriv.variables[0] for i in
deriv.variables) and not ics[funcarg].has(f)):
dorder = ode_order(deriv, x)
temp = 'f' + str(dorder)
boundary.update({temp: new, temp + 'val': ics[funcarg]})
else:
raise ValueError("Enter valid boundary conditions for Derivatives")
# Separating functions
elif isinstance(funcarg, AppliedUndef):
if (funcarg.func == f and len(funcarg.args) == 1 and
not funcarg.args[0].has(x) and not ics[funcarg].has(f)):
boundary.update({'f0': funcarg.args[0], 'f0val': ics[funcarg]})
else:
raise ValueError("Enter valid boundary conditions for Function")
else:
raise ValueError("Enter boundary conditions of the form ics={f(point}: value, f(x).diff(x, order).subs(x, point): value}")
# Precondition to try remove f(x) from highest order derivative
reduced_eq = None
if eq.is_Add:
deriv_coef = eq.coeff(f(x).diff(x, order))
if deriv_coef not in (1, 0):
r = deriv_coef.match(a*f(x)**c1)
if r and r[c1]:
den = f(x)**r[c1]
reduced_eq = Add(*[arg/den for arg in eq.args])
if not reduced_eq:
reduced_eq = eq
if order == 1:
## Linear case: a(x)*y'+b(x)*y+c(x) == 0
if eq.is_Add:
ind, dep = reduced_eq.as_independent(f)
else:
u = Dummy('u')
ind, dep = (reduced_eq + u).as_independent(f)
ind, dep = [tmp.subs(u, 0) for tmp in [ind, dep]]
r = {a: dep.coeff(df),
b: dep.coeff(f(x)),
c: ind}
# double check f[a] since the preconditioning may have failed
if not r[a].has(f) and not r[b].has(f) and (
r[a]*df + r[b]*f(x) + r[c]).expand() - reduced_eq == 0:
r['a'] = a
r['b'] = b
r['c'] = c
matching_hints["1st_linear"] = r
matching_hints["1st_linear_Integral"] = r
## Bernoulli case: a(x)*y'+b(x)*y+c(x)*y**n == 0
r = collect(
reduced_eq, f(x), exact=True).match(a*df + b*f(x) + c*f(x)**n)
if r and r[c] != 0 and r[n] != 1: # See issue 4676
r['a'] = a
r['b'] = b
r['c'] = c
r['n'] = n
matching_hints["Bernoulli"] = r
matching_hints["Bernoulli_Integral"] = r
## Riccati special n == -2 case: a2*y'+b2*y**2+c2*y/x+d2/x**2 == 0
r = collect(reduced_eq,
f(x), exact=True).match(a2*df + b2*f(x)**2 + c2*f(x)/x + d2/x**2)
if r and r[b2] != 0 and (r[c2] != 0 or r[d2] != 0):
r['a2'] = a2
r['b2'] = b2
r['c2'] = c2
r['d2'] = d2
matching_hints["Riccati_special_minus2"] = r
# NON-REDUCED FORM OF EQUATION matches
r = collect(eq, df, exact=True).match(d + e * df)
if r:
r['d'] = d
r['e'] = e
r['y'] = y
r[d] = r[d].subs(f(x), y)
r[e] = r[e].subs(f(x), y)
# FIRST ORDER POWER SERIES WHICH NEEDS INITIAL CONDITIONS
# TODO: Hint first order series should match only if d/e is analytic.
# For now, only d/e and (d/e).diff(arg) is checked for existence at
# at a given point.
# This is currently done internally in ode_1st_power_series.
point = boundary.get('f0', 0)
value = boundary.get('f0val', C1)
check = cancel(r[d]/r[e])
check1 = check.subs({x: point, y: value})
if not check1.has(oo) and not check1.has(zoo) and \
not check1.has(NaN) and not check1.has(-oo):
check2 = (check1.diff(x)).subs({x: point, y: value})
if not check2.has(oo) and not check2.has(zoo) and \
not check2.has(NaN) and not check2.has(-oo):
rseries = r.copy()
rseries.update({'terms': terms, 'f0': point, 'f0val': value})
matching_hints["1st_power_series"] = rseries
r3.update(r)
## Exact Differential Equation: P(x, y) + Q(x, y)*y' = 0 where
# dP/dy == dQ/dx
try:
if r[d] != 0:
numerator = simplify(r[d].diff(y) - r[e].diff(x))
# The following few conditions try to convert a non-exact
# differential equation into an exact one.
# References : Differential equations with applications
# and historical notes - George E. Simmons
if numerator:
# If (dP/dy - dQ/dx) / Q = f(x)
# then exp(integral(f(x))*equation becomes exact
factor = simplify(numerator/r[e])
variables = factor.free_symbols
if len(variables) == 1 and x == variables.pop():
factor = exp(Integral(factor).doit())
r[d] *= factor
r[e] *= factor
matching_hints["1st_exact"] = r
matching_hints["1st_exact_Integral"] = r
else:
# If (dP/dy - dQ/dx) / -P = f(y)
# then exp(integral(f(y))*equation becomes exact
factor = simplify(-numerator/r[d])
variables = factor.free_symbols
if len(variables) == 1 and y == variables.pop():
factor = exp(Integral(factor).doit())
r[d] *= factor
r[e] *= factor
matching_hints["1st_exact"] = r
matching_hints["1st_exact_Integral"] = r
else:
matching_hints["1st_exact"] = r
matching_hints["1st_exact_Integral"] = r
except NotImplementedError:
# Differentiating the coefficients might fail because of things
# like f(2*x).diff(x). See issue 4624 and issue 4719.
pass
# Any first order ODE can be ideally solved by the Lie Group
# method
matching_hints["lie_group"] = r3
# This match is used for several cases below; we now collect on
# f(x) so the matching works.
r = collect(reduced_eq, df, exact=True).match(d + e*df)
if r:
# Using r[d] and r[e] without any modification for hints
# linear-coefficients and separable-reduced.
num, den = r[d], r[e] # ODE = d/e + df
r['d'] = d
r['e'] = e
r['y'] = y
r[d] = num.subs(f(x), y)
r[e] = den.subs(f(x), y)
## Separable Case: y' == P(y)*Q(x)
r[d] = separatevars(r[d])
r[e] = separatevars(r[e])
# m1[coeff]*m1[x]*m1[y] + m2[coeff]*m2[x]*m2[y]*y'
m1 = separatevars(r[d], dict=True, symbols=(x, y))
m2 = separatevars(r[e], dict=True, symbols=(x, y))
if m1 and m2:
r1 = {'m1': m1, 'm2': m2, 'y': y}
matching_hints["separable"] = r1
matching_hints["separable_Integral"] = r1
## First order equation with homogeneous coefficients:
# dy/dx == F(y/x) or dy/dx == F(x/y)
ordera = homogeneous_order(r[d], x, y)
if ordera is not None:
orderb = homogeneous_order(r[e], x, y)
if ordera == orderb:
# u1=y/x and u2=x/y
u1 = Dummy('u1')
u2 = Dummy('u2')
s = "1st_homogeneous_coeff_subs"
s1 = s + "_dep_div_indep"
s2 = s + "_indep_div_dep"
if simplify((r[d] + u1*r[e]).subs({x: 1, y: u1})) != 0:
matching_hints[s1] = r
matching_hints[s1 + "_Integral"] = r
if simplify((r[e] + u2*r[d]).subs({x: u2, y: 1})) != 0:
matching_hints[s2] = r
matching_hints[s2 + "_Integral"] = r
if s1 in matching_hints and s2 in matching_hints:
matching_hints["1st_homogeneous_coeff_best"] = r
## Linear coefficients of the form
# y'+ F((a*x + b*y + c)/(a'*x + b'y + c')) = 0
# that can be reduced to homogeneous form.
F = num/den
params = _linear_coeff_match(F, func)
if params:
xarg, yarg = params
u = Dummy('u')
t = Dummy('t')
# Dummy substitution for df and f(x).
dummy_eq = reduced_eq.subs(((df, t), (f(x), u)))
reps = ((x, x + xarg), (u, u + yarg), (t, df), (u, f(x)))
dummy_eq = simplify(dummy_eq.subs(reps))
# get the re-cast values for e and d
r2 = collect(expand(dummy_eq), [df, f(x)]).match(e*df + d)
if r2:
orderd = homogeneous_order(r2[d], x, f(x))
if orderd is not None:
ordere = homogeneous_order(r2[e], x, f(x))
if orderd == ordere:
# Match arguments are passed in such a way that it
# is coherent with the already existing homogeneous
# functions.
r2[d] = r2[d].subs(f(x), y)
r2[e] = r2[e].subs(f(x), y)
r2.update({'xarg': xarg, 'yarg': yarg,
'd': d, 'e': e, 'y': y})
matching_hints["linear_coefficients"] = r2
matching_hints["linear_coefficients_Integral"] = r2
## Equation of the form y' + (y/x)*H(x^n*y) = 0
# that can be reduced to separable form
factor = simplify(x/f(x)*num/den)
# Try representing factor in terms of x^n*y
# where n is lowest power of x in factor;
# first remove terms like sqrt(2)*3 from factor.atoms(Mul)
u = None
for mul in ordered(factor.atoms(Mul)):
if mul.has(x):
_, u = mul.as_independent(x, f(x))
break
if u and u.has(f(x)):
h = x**(degree(Poly(u.subs(f(x), y), gen=x)))*f(x)
p = Wild('p')
if (u/h == 1) or ((u/h).simplify().match(x**p)):
t = Dummy('t')
r2 = {'t': t}
xpart, ypart = u.as_independent(f(x))
test = factor.subs(((u, t), (1/u, 1/t)))
free = test.free_symbols
if len(free) == 1 and free.pop() == t:
r2.update({'power': xpart.as_base_exp()[1], 'u': test})
matching_hints["separable_reduced"] = r2
matching_hints["separable_reduced_Integral"] = r2
## Almost-linear equation of the form f(x)*g(y)*y' + k(x)*l(y) + m(x) = 0
r = collect(eq, [df, f(x)]).match(e*df + d)
if r:
r2 = r.copy()
r2[c] = S.Zero
if r2[d].is_Add:
# Separate the terms having f(x) to r[d] and
# remaining to r[c]
no_f, r2[d] = r2[d].as_independent(f(x))
r2[c] += no_f
factor = simplify(r2[d].diff(f(x))/r[e])
if factor and not factor.has(f(x)):
r2[d] = factor_terms(r2[d])
u = r2[d].as_independent(f(x), as_Add=False)[1]
r2.update({'a': e, 'b': d, 'c': c, 'u': u})
r2[d] /= u
r2[e] /= u.diff(f(x))
matching_hints["almost_linear"] = r2
matching_hints["almost_linear_Integral"] = r2
elif order == 2:
# Liouville ODE in the form
# f(x).diff(x, 2) + g(f(x))*(f(x).diff(x))**2 + h(x)*f(x).diff(x)
# See Goldstein and Braun, "Advanced Methods for the Solution of
# Differential Equations", pg. 98
s = d*f(x).diff(x, 2) + e*df**2 + k*df
r = reduced_eq.match(s)
if r and r[d] != 0:
y = Dummy('y')
g = simplify(r[e]/r[d]).subs(f(x), y)
h = simplify(r[k]/r[d]).subs(f(x), y)
if y in h.free_symbols or x in g.free_symbols:
pass
else:
r = {'g': g, 'h': h, 'y': y}
matching_hints["Liouville"] = r
matching_hints["Liouville_Integral"] = r
# Homogeneous second order differential equation of the form
# a3*f(x).diff(x, 2) + b3*f(x).diff(x) + c3, where
# for simplicity, a3, b3 and c3 are assumed to be polynomials.
# It has a definite power series solution at point x0 if, b3/a3 and c3/a3
# are analytic at x0.
deq = a3*(f(x).diff(x, 2)) + b3*df + c3*f(x)
r = collect(reduced_eq,
[f(x).diff(x, 2), f(x).diff(x), f(x)]).match(deq)
ordinary = False
if r and r[a3] != 0:
if all([r[key].is_polynomial() for key in r]):
p = cancel(r[b3]/r[a3]) # Used below
q = cancel(r[c3]/r[a3]) # Used below
point = kwargs.get('x0', 0)
check = p.subs(x, point)
if not check.has(oo) and not check.has(NaN) and \
not check.has(zoo) and not check.has(-oo):
check = q.subs(x, point)
if not check.has(oo) and not check.has(NaN) and \
not check.has(zoo) and not check.has(-oo):
ordinary = True
r.update({'a3': a3, 'b3': b3, 'c3': c3, 'x0': point, 'terms': terms})
matching_hints["2nd_power_series_ordinary"] = r
# Checking if the differential equation has a regular singular point
# at x0. It has a regular singular point at x0, if (b3/a3)*(x - x0)
# and (c3/a3)*((x - x0)**2) are analytic at x0.
if not ordinary:
p = cancel((x - point)*p)
check = p.subs(x, point)
if not check.has(oo) and not check.has(NaN) and \
not check.has(zoo) and not check.has(-oo):
q = cancel(((x - point)**2)*q)
check = q.subs(x, point)
if not check.has(oo) and not check.has(NaN) and \
not check.has(zoo) and not check.has(-oo):
coeff_dict = {'p': p, 'q': q, 'x0': point, 'terms': terms}
matching_hints["2nd_power_series_regular"] = coeff_dict
if order > 0:
# Any ODE that can be solved with a combination of algebra and
# integrals e.g.:
# d^3/dx^3(x y) = F(x)
r = _nth_algebraic_match(reduced_eq, func)
if r['solutions']:
matching_hints['nth_algebraic'] = r
matching_hints['nth_algebraic_Integral'] = r
# nth order linear ODE
# a_n(x)y^(n) + ... + a_1(x)y' + a_0(x)y = F(x) = b
r = _nth_linear_match(reduced_eq, func, order)
# Constant coefficient case (a_i is constant for all i)
if r and not any(r[i].has(x) for i in r if i >= 0):
# Inhomogeneous case: F(x) is not identically 0
if r[-1]:
undetcoeff = _undetermined_coefficients_match(r[-1], x)
s = "nth_linear_constant_coeff_variation_of_parameters"
matching_hints[s] = r
matching_hints[s + "_Integral"] = r
if undetcoeff['test']:
r['trialset'] = undetcoeff['trialset']
matching_hints[
"nth_linear_constant_coeff_undetermined_coefficients"
] = r
# Homogeneous case: F(x) is identically 0
else:
matching_hints["nth_linear_constant_coeff_homogeneous"] = r
# nth order Euler equation a_n*x**n*y^(n) + ... + a_1*x*y' + a_0*y = F(x)
#In case of Homogeneous euler equation F(x) = 0
def _test_term(coeff, order):
r"""
Linear Euler ODEs have the form K*x**order*diff(y(x),x,order) = F(x),
where K is independent of x and y(x), order>= 0.
So we need to check that for each term, coeff == K*x**order from
some K. We have a few cases, since coeff may have several
different types.
"""
if order < 0:
raise ValueError("order should be greater than 0")
if coeff == 0:
return True
if order == 0:
if x in coeff.free_symbols:
return False
return True
if coeff.is_Mul:
if coeff.has(f(x)):
return False
return x**order in coeff.args
elif coeff.is_Pow:
return coeff.as_base_exp() == (x, order)
elif order == 1:
return x == coeff
return False
# Find coefficient for higest derivative, multiply coefficients to
# bring the equation into Euler form if possible
r_rescaled = None
if r is not None:
coeff = r[order]
factor = x**order / coeff
r_rescaled = {i: factor*r[i] for i in r}
if r_rescaled and not any(not _test_term(r_rescaled[i], i) for i in
r_rescaled if i != 'trialset' and i >= 0):
if not r_rescaled[-1]:
matching_hints["nth_linear_euler_eq_homogeneous"] = r_rescaled
else:
matching_hints["nth_linear_euler_eq_nonhomogeneous_variation_of_parameters"] = r_rescaled
matching_hints["nth_linear_euler_eq_nonhomogeneous_variation_of_parameters_Integral"] = r_rescaled
e, re = posify(r_rescaled[-1].subs(x, exp(x)))
undetcoeff = _undetermined_coefficients_match(e.subs(re), x)
if undetcoeff['test']:
r_rescaled['trialset'] = undetcoeff['trialset']
matching_hints["nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients"] = r_rescaled
# Order keys based on allhints.
retlist = [i for i in allhints if i in matching_hints]
if dict:
# Dictionaries are ordered arbitrarily, so make note of which
# hint would come first for dsolve(). Use an ordered dict in Py 3.
matching_hints["default"] = retlist[0] if retlist else None
matching_hints["ordered_hints"] = tuple(retlist)
return matching_hints
else:
return tuple(retlist)
def classify_sysode(eq, funcs=None, **kwargs):
r"""
Returns a dictionary of parameter names and values that define the system
of ordinary differential equations in ``eq``.
The parameters are further used in
:py:meth:`~sympy.solvers.ode.dsolve` for solving that system.
The parameter names and values are:
'is_linear' (boolean), which tells whether the given system is linear.
Note that "linear" here refers to the operator: terms such as ``x*diff(x,t)`` are
nonlinear, whereas terms like ``sin(t)*diff(x,t)`` are still linear operators.
'func' (list) contains the :py:class:`~sympy.core.function.Function`s that
appear with a derivative in the ODE, i.e. those that we are trying to solve
the ODE for.
'order' (dict) with the maximum derivative for each element of the 'func'
parameter.
'func_coeff' (dict) with the coefficient for each triple ``(equation number,
function, order)```. The coefficients are those subexpressions that do not
appear in 'func', and hence can be considered constant for purposes of ODE
solving.
'eq' (list) with the equations from ``eq``, sympified and transformed into
expressions (we are solving for these expressions to be zero).
'no_of_equations' (int) is the number of equations (same as ``len(eq)``).
'type_of_equation' (string) is an internal classification of the type of
ODE.
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode-toc1.htm
-A. D. Polyanin and A. V. Manzhirov, Handbook of Mathematics for Engineers and Scientists
Examples
========
>>> from sympy import Function, Eq, symbols, diff
>>> from sympy.solvers.ode import classify_sysode
>>> from sympy.abc import t
>>> f, x, y = symbols('f, x, y', cls=Function)
>>> k, l, m, n = symbols('k, l, m, n', Integer=True)
>>> x1 = diff(x(t), t) ; y1 = diff(y(t), t)
>>> x2 = diff(x(t), t, t) ; y2 = diff(y(t), t, t)
>>> eq = (Eq(5*x1, 12*x(t) - 6*y(t)), Eq(2*y1, 11*x(t) + 3*y(t)))
>>> classify_sysode(eq)
{'eq': [-12*x(t) + 6*y(t) + 5*Derivative(x(t), t), -11*x(t) - 3*y(t) + 2*Derivative(y(t), t)],
'func': [x(t), y(t)], 'func_coeff': {(0, x(t), 0): -12, (0, x(t), 1): 5, (0, y(t), 0): 6,
(0, y(t), 1): 0, (1, x(t), 0): -11, (1, x(t), 1): 0, (1, y(t), 0): -3, (1, y(t), 1): 2},
'is_linear': True, 'no_of_equation': 2, 'order': {x(t): 1, y(t): 1}, 'type_of_equation': 'type1'}
>>> eq = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), -t**2*x(t) + 5*t*y(t)))
>>> classify_sysode(eq)
{'eq': [-t**2*y(t) - 5*t*x(t) + Derivative(x(t), t), t**2*x(t) - 5*t*y(t) + Derivative(y(t), t)],
'func': [x(t), y(t)], 'func_coeff': {(0, x(t), 0): -5*t, (0, x(t), 1): 1, (0, y(t), 0): -t**2,
(0, y(t), 1): 0, (1, x(t), 0): t**2, (1, x(t), 1): 0, (1, y(t), 0): -5*t, (1, y(t), 1): 1},
'is_linear': True, 'no_of_equation': 2, 'order': {x(t): 1, y(t): 1}, 'type_of_equation': 'type4'}
"""
# Sympify equations and convert iterables of equations into
# a list of equations
def _sympify(eq):
return list(map(sympify, eq if iterable(eq) else [eq]))
eq, funcs = (_sympify(w) for w in [eq, funcs])
for i, fi in enumerate(eq):
if isinstance(fi, Equality):
eq[i] = fi.lhs - fi.rhs
matching_hints = {"no_of_equation":i+1}
matching_hints['eq'] = eq
if i==0:
raise ValueError("classify_sysode() works for systems of ODEs. "
"For scalar ODEs, classify_ode should be used")
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
# find all the functions if not given
order = dict()
if funcs==[None]:
funcs = []
for eqs in eq:
derivs = eqs.atoms(Derivative)
func = set().union(*[d.atoms(AppliedUndef) for d in derivs])
for func_ in func:
funcs.append(func_)
funcs = list(set(funcs))
if len(funcs) < len(eq):
raise ValueError("Number of functions given is less than number of equations %s" % funcs)
func_dict = dict()
for func in funcs:
if not order.get(func, False):
max_order = 0
for i, eqs_ in enumerate(eq):
order_ = ode_order(eqs_,func)
if max_order < order_:
max_order = order_
eq_no = i
if eq_no in func_dict:
list_func = []
list_func.append(func_dict[eq_no])
list_func.append(func)
func_dict[eq_no] = list_func
else:
func_dict[eq_no] = func
order[func] = max_order
funcs = [func_dict[i] for i in range(len(func_dict))]
matching_hints['func'] = funcs
for func in funcs:
if isinstance(func, list):
for func_elem in func:
if len(func_elem.args) != 1:
raise ValueError("dsolve() and classify_sysode() work with "
"functions of one variable only, not %s" % func)
else:
if func and len(func.args) != 1:
raise ValueError("dsolve() and classify_sysode() work with "
"functions of one variable only, not %s" % func)
# find the order of all equation in system of odes
matching_hints["order"] = order
# find coefficients of terms f(t), diff(f(t),t) and higher derivatives
# and similarly for other functions g(t), diff(g(t),t) in all equations.
# Here j denotes the equation number, funcs[l] denotes the function about
# which we are talking about and k denotes the order of function funcs[l]
# whose coefficient we are calculating.
def linearity_check(eqs, j, func, is_linear_):
for k in range(order[func] + 1):
func_coef[j, func, k] = collect(eqs.expand(), [diff(func, t, k)]).coeff(diff(func, t, k))
if is_linear_ == True:
if func_coef[j, func, k] == 0:
if k == 0:
coef = eqs.as_independent(func, as_Add=True)[1]
for xr in range(1, ode_order(eqs,func) + 1):
coef -= eqs.as_independent(diff(func, t, xr), as_Add=True)[1]
if coef != 0:
is_linear_ = False
else:
if eqs.as_independent(diff(func, t, k), as_Add=True)[1]:
is_linear_ = False
else:
for func_ in funcs:
if isinstance(func_, list):
for elem_func_ in func_:
dep = func_coef[j, func, k].as_independent(elem_func_, as_Add=True)[1]
if dep != 0:
is_linear_ = False
else:
dep = func_coef[j, func, k].as_independent(func_, as_Add=True)[1]
if dep != 0:
is_linear_ = False
return is_linear_
func_coef = {}
is_linear = True
for j, eqs in enumerate(eq):
for func in funcs:
if isinstance(func, list):
for func_elem in func:
is_linear = linearity_check(eqs, j, func_elem, is_linear)
else:
is_linear = linearity_check(eqs, j, func, is_linear)
matching_hints['func_coeff'] = func_coef
matching_hints['is_linear'] = is_linear
if len(set(order.values()))==1:
order_eq = list(matching_hints['order'].values())[0]
if matching_hints['is_linear'] == True:
if matching_hints['no_of_equation'] == 2:
if order_eq == 1:
type_of_equation = check_linear_2eq_order1(eq, funcs, func_coef)
elif order_eq == 2:
type_of_equation = check_linear_2eq_order2(eq, funcs, func_coef)
else:
type_of_equation = None
elif matching_hints['no_of_equation'] == 3:
if order_eq == 1:
type_of_equation = check_linear_3eq_order1(eq, funcs, func_coef)
if type_of_equation==None:
type_of_equation = check_linear_neq_order1(eq, funcs, func_coef)
else:
type_of_equation = None
else:
if order_eq == 1:
type_of_equation = check_linear_neq_order1(eq, funcs, func_coef)
else:
type_of_equation = None
else:
if matching_hints['no_of_equation'] == 2:
if order_eq == 1:
type_of_equation = check_nonlinear_2eq_order1(eq, funcs, func_coef)
else:
type_of_equation = None
elif matching_hints['no_of_equation'] == 3:
if order_eq == 1:
type_of_equation = check_nonlinear_3eq_order1(eq, funcs, func_coef)
else:
type_of_equation = None
else:
type_of_equation = None
else:
type_of_equation = None
matching_hints['type_of_equation'] = type_of_equation
return matching_hints
def check_linear_2eq_order1(eq, func, func_coef):
x = func[0].func
y = func[1].func
fc = func_coef
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
r = dict()
# for equations Eq(a1*diff(x(t),t), b1*x(t) + c1*y(t) + d1)
# and Eq(a2*diff(y(t),t), b2*x(t) + c2*y(t) + d2)
r['a1'] = fc[0,x(t),1] ; r['a2'] = fc[1,y(t),1]
r['b1'] = -fc[0,x(t),0]/fc[0,x(t),1] ; r['b2'] = -fc[1,x(t),0]/fc[1,y(t),1]
r['c1'] = -fc[0,y(t),0]/fc[0,x(t),1] ; r['c2'] = -fc[1,y(t),0]/fc[1,y(t),1]
forcing = [S(0),S(0)]
for i in range(2):
for j in Add.make_args(eq[i]):
if not j.has(x(t), y(t)):
forcing[i] += j
if not (forcing[0].has(t) or forcing[1].has(t)):
# We can handle homogeneous case and simple constant forcings
r['d1'] = forcing[0]
r['d2'] = forcing[1]
else:
# Issue #9244: nonhomogeneous linear systems are not supported
return None
# Conditions to check for type 6 whose equations are Eq(diff(x(t),t), f(t)*x(t) + g(t)*y(t)) and
# Eq(diff(y(t),t), a*[f(t) + a*h(t)]x(t) + a*[g(t) - h(t)]*y(t))
p = 0
q = 0
p1 = cancel(r['b2']/(cancel(r['b2']/r['c2']).as_numer_denom()[0]))
p2 = cancel(r['b1']/(cancel(r['b1']/r['c1']).as_numer_denom()[0]))
for n, i in enumerate([p1, p2]):
for j in Mul.make_args(collect_const(i)):
if not j.has(t):
q = j
if q and n==0:
if ((r['b2']/j - r['b1'])/(r['c1'] - r['c2']/j)) == j:
p = 1
elif q and n==1:
if ((r['b1']/j - r['b2'])/(r['c2'] - r['c1']/j)) == j:
p = 2
# End of condition for type 6
if r['d1']!=0 or r['d2']!=0:
if not r['d1'].has(t) and not r['d2'].has(t):
if all(not r[k].has(t) for k in 'a1 a2 b1 b2 c1 c2'.split()):
# Equations for type 2 are Eq(a1*diff(x(t),t),b1*x(t)+c1*y(t)+d1) and Eq(a2*diff(y(t),t),b2*x(t)+c2*y(t)+d2)
return "type2"
else:
return None
else:
if all(not r[k].has(t) for k in 'a1 a2 b1 b2 c1 c2'.split()):
# Equations for type 1 are Eq(a1*diff(x(t),t),b1*x(t)+c1*y(t)) and Eq(a2*diff(y(t),t),b2*x(t)+c2*y(t))
return "type1"
else:
r['b1'] = r['b1']/r['a1'] ; r['b2'] = r['b2']/r['a2']
r['c1'] = r['c1']/r['a1'] ; r['c2'] = r['c2']/r['a2']
if (r['b1'] == r['c2']) and (r['c1'] == r['b2']):
# Equation for type 3 are Eq(diff(x(t),t), f(t)*x(t) + g(t)*y(t)) and Eq(diff(y(t),t), g(t)*x(t) + f(t)*y(t))
return "type3"
elif (r['b1'] == r['c2']) and (r['c1'] == -r['b2']) or (r['b1'] == -r['c2']) and (r['c1'] == r['b2']):
# Equation for type 4 are Eq(diff(x(t),t), f(t)*x(t) + g(t)*y(t)) and Eq(diff(y(t),t), -g(t)*x(t) + f(t)*y(t))
return "type4"
elif (not cancel(r['b2']/r['c1']).has(t) and not cancel((r['c2']-r['b1'])/r['c1']).has(t)) \
or (not cancel(r['b1']/r['c2']).has(t) and not cancel((r['c1']-r['b2'])/r['c2']).has(t)):
# Equations for type 5 are Eq(diff(x(t),t), f(t)*x(t) + g(t)*y(t)) and Eq(diff(y(t),t), a*g(t)*x(t) + [f(t) + b*g(t)]*y(t)
return "type5"
elif p:
return "type6"
else:
# Equations for type 7 are Eq(diff(x(t),t), f(t)*x(t) + g(t)*y(t)) and Eq(diff(y(t),t), h(t)*x(t) + p(t)*y(t))
return "type7"
def check_linear_2eq_order2(eq, func, func_coef):
x = func[0].func
y = func[1].func
fc = func_coef
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
r = dict()
a = Wild('a', exclude=[1/t])
b = Wild('b', exclude=[1/t**2])
u = Wild('u', exclude=[t, t**2])
v = Wild('v', exclude=[t, t**2])
w = Wild('w', exclude=[t, t**2])
p = Wild('p', exclude=[t, t**2])
r['a1'] = fc[0,x(t),2] ; r['a2'] = fc[1,y(t),2]
r['b1'] = fc[0,x(t),1] ; r['b2'] = fc[1,x(t),1]
r['c1'] = fc[0,y(t),1] ; r['c2'] = fc[1,y(t),1]
r['d1'] = fc[0,x(t),0] ; r['d2'] = fc[1,x(t),0]
r['e1'] = fc[0,y(t),0] ; r['e2'] = fc[1,y(t),0]
const = [S(0), S(0)]
for i in range(2):
for j in Add.make_args(eq[i]):
if not (j.has(x(t)) or j.has(y(t))):
const[i] += j
r['f1'] = const[0]
r['f2'] = const[1]
if r['f1']!=0 or r['f2']!=0:
if all(not r[k].has(t) for k in 'a1 a2 d1 d2 e1 e2 f1 f2'.split()) \
and r['b1']==r['c1']==r['b2']==r['c2']==0:
return "type2"
elif all(not r[k].has(t) for k in 'a1 a2 b1 b2 c1 c2 d1 d2 e1 e1'.split()):
p = [S(0), S(0)] ; q = [S(0), S(0)]
for n, e in enumerate([r['f1'], r['f2']]):
if e.has(t):
tpart = e.as_independent(t, Mul)[1]
for i in Mul.make_args(tpart):
if i.has(exp):
b, e = i.as_base_exp()
co = e.coeff(t)
if co and not co.has(t) and co.has(I):
p[n] = 1
else:
q[n] = 1
else:
q[n] = 1
else:
q[n] = 1
if p[0]==1 and p[1]==1 and q[0]==0 and q[1]==0:
return "type4"
else:
return None
else:
return None
else:
if r['b1']==r['b2']==r['c1']==r['c2']==0 and all(not r[k].has(t) \
for k in 'a1 a2 d1 d2 e1 e2'.split()):
return "type1"
elif r['b1']==r['e1']==r['c2']==r['d2']==0 and all(not r[k].has(t) \
for k in 'a1 a2 b2 c1 d1 e2'.split()) and r['c1'] == -r['b2'] and \
r['d1'] == r['e2']:
return "type3"
elif cancel(-r['b2']/r['d2'])==t and cancel(-r['c1']/r['e1'])==t and not \
(r['d2']/r['a2']).has(t) and not (r['e1']/r['a1']).has(t) and \
r['b1']==r['d1']==r['c2']==r['e2']==0:
return "type5"
elif ((r['a1']/r['d1']).expand()).match((p*(u*t**2+v*t+w)**2).expand()) and not \
(cancel(r['a1']*r['d2']/(r['a2']*r['d1']))).has(t) and not (r['d1']/r['e1']).has(t) and not \
(r['d2']/r['e2']).has(t) and r['b1'] == r['b2'] == r['c1'] == r['c2'] == 0:
return "type10"
elif not cancel(r['d1']/r['e1']).has(t) and not cancel(r['d2']/r['e2']).has(t) and not \
cancel(r['d1']*r['a2']/(r['d2']*r['a1'])).has(t) and r['b1']==r['b2']==r['c1']==r['c2']==0:
return "type6"
elif not cancel(r['b1']/r['c1']).has(t) and not cancel(r['b2']/r['c2']).has(t) and not \
cancel(r['b1']*r['a2']/(r['b2']*r['a1'])).has(t) and r['d1']==r['d2']==r['e1']==r['e2']==0:
return "type7"
elif cancel(-r['b2']/r['d2'])==t and cancel(-r['c1']/r['e1'])==t and not \
cancel(r['e1']*r['a2']/(r['d2']*r['a1'])).has(t) and r['e1'].has(t) \
and r['b1']==r['d1']==r['c2']==r['e2']==0:
return "type8"
elif (r['b1']/r['a1']).match(a/t) and (r['b2']/r['a2']).match(a/t) and not \
(r['b1']/r['c1']).has(t) and not (r['b2']/r['c2']).has(t) and \
(r['d1']/r['a1']).match(b/t**2) and (r['d2']/r['a2']).match(b/t**2) \
and not (r['d1']/r['e1']).has(t) and not (r['d2']/r['e2']).has(t):
return "type9"
elif -r['b1']/r['d1']==-r['c1']/r['e1']==-r['b2']/r['d2']==-r['c2']/r['e2']==t:
return "type11"
else:
return None
def check_linear_3eq_order1(eq, func, func_coef):
x = func[0].func
y = func[1].func
z = func[2].func
fc = func_coef
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
r = dict()
r['a1'] = fc[0,x(t),1]; r['a2'] = fc[1,y(t),1]; r['a3'] = fc[2,z(t),1]
r['b1'] = fc[0,x(t),0]; r['b2'] = fc[1,x(t),0]; r['b3'] = fc[2,x(t),0]
r['c1'] = fc[0,y(t),0]; r['c2'] = fc[1,y(t),0]; r['c3'] = fc[2,y(t),0]
r['d1'] = fc[0,z(t),0]; r['d2'] = fc[1,z(t),0]; r['d3'] = fc[2,z(t),0]
forcing = [S(0), S(0), S(0)]
for i in range(3):
for j in Add.make_args(eq[i]):
if not j.has(x(t), y(t), z(t)):
forcing[i] += j
if forcing[0].has(t) or forcing[1].has(t) or forcing[2].has(t):
# We can handle homogeneous case and simple constant forcings.
# Issue #9244: nonhomogeneous linear systems are not supported
return None
if all(not r[k].has(t) for k in 'a1 a2 a3 b1 b2 b3 c1 c2 c3 d1 d2 d3'.split()):
if r['c1']==r['d1']==r['d2']==0:
return 'type1'
elif r['c1'] == -r['b2'] and r['d1'] == -r['b3'] and r['d2'] == -r['c3'] \
and r['b1'] == r['c2'] == r['d3'] == 0:
return 'type2'
elif r['b1'] == r['c2'] == r['d3'] == 0 and r['c1']/r['a1'] == -r['d1']/r['a1'] \
and r['d2']/r['a2'] == -r['b2']/r['a2'] and r['b3']/r['a3'] == -r['c3']/r['a3']:
return 'type3'
else:
return None
else:
for k1 in 'c1 d1 b2 d2 b3 c3'.split():
if r[k1] == 0:
continue
else:
if all(not cancel(r[k1]/r[k]).has(t) for k in 'd1 b2 d2 b3 c3'.split() if r[k]!=0) \
and all(not cancel(r[k1]/(r['b1'] - r[k])).has(t) for k in 'b1 c2 d3'.split() if r['b1']!=r[k]):
return 'type4'
else:
break
return None
def check_linear_neq_order1(eq, func, func_coef):
x = func[0].func
y = func[1].func
z = func[2].func
fc = func_coef
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
r = dict()
n = len(eq)
for i in range(n):
for j in range(n):
if (fc[i,func[j],0]/fc[i,func[i],1]).has(t):
return None
if len(eq)==3:
return 'type6'
return 'type1'
def check_nonlinear_2eq_order1(eq, func, func_coef):
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
f = Wild('f')
g = Wild('g')
u, v = symbols('u, v', cls=Dummy)
def check_type(x, y):
r1 = eq[0].match(t*diff(x(t),t) - x(t) + f)
r2 = eq[1].match(t*diff(y(t),t) - y(t) + g)
if not (r1 and r2):
r1 = eq[0].match(diff(x(t),t) - x(t)/t + f/t)
r2 = eq[1].match(diff(y(t),t) - y(t)/t + g/t)
if not (r1 and r2):
r1 = (-eq[0]).match(t*diff(x(t),t) - x(t) + f)
r2 = (-eq[1]).match(t*diff(y(t),t) - y(t) + g)
if not (r1 and r2):
r1 = (-eq[0]).match(diff(x(t),t) - x(t)/t + f/t)
r2 = (-eq[1]).match(diff(y(t),t) - y(t)/t + g/t)
if r1 and r2 and not (r1[f].subs(diff(x(t),t),u).subs(diff(y(t),t),v).has(t) \
or r2[g].subs(diff(x(t),t),u).subs(diff(y(t),t),v).has(t)):
return 'type5'
else:
return None
for func_ in func:
if isinstance(func_, list):
x = func[0][0].func
y = func[0][1].func
eq_type = check_type(x, y)
if not eq_type:
eq_type = check_type(y, x)
return eq_type
x = func[0].func
y = func[1].func
fc = func_coef
n = Wild('n', exclude=[x(t),y(t)])
f1 = Wild('f1', exclude=[v,t])
f2 = Wild('f2', exclude=[v,t])
g1 = Wild('g1', exclude=[u,t])
g2 = Wild('g2', exclude=[u,t])
for i in range(2):
eqs = 0
for terms in Add.make_args(eq[i]):
eqs += terms/fc[i,func[i],1]
eq[i] = eqs
r = eq[0].match(diff(x(t),t) - x(t)**n*f)
if r:
g = (diff(y(t),t) - eq[1])/r[f]
if r and not (g.has(x(t)) or g.subs(y(t),v).has(t) or r[f].subs(x(t),u).subs(y(t),v).has(t)):
return 'type1'
r = eq[0].match(diff(x(t),t) - exp(n*x(t))*f)
if r:
g = (diff(y(t),t) - eq[1])/r[f]
if r and not (g.has(x(t)) or g.subs(y(t),v).has(t) or r[f].subs(x(t),u).subs(y(t),v).has(t)):
return 'type2'
g = Wild('g')
r1 = eq[0].match(diff(x(t),t) - f)
r2 = eq[1].match(diff(y(t),t) - g)
if r1 and r2 and not (r1[f].subs(x(t),u).subs(y(t),v).has(t) or \
r2[g].subs(x(t),u).subs(y(t),v).has(t)):
return 'type3'
r1 = eq[0].match(diff(x(t),t) - f)
r2 = eq[1].match(diff(y(t),t) - g)
num, den = (
(r1[f].subs(x(t),u).subs(y(t),v))/
(r2[g].subs(x(t),u).subs(y(t),v))).as_numer_denom()
R1 = num.match(f1*g1)
R2 = den.match(f2*g2)
phi = (r1[f].subs(x(t),u).subs(y(t),v))/num
if R1 and R2:
return 'type4'
return None
def check_nonlinear_2eq_order2(eq, func, func_coef):
return None
def check_nonlinear_3eq_order1(eq, func, func_coef):
x = func[0].func
y = func[1].func
z = func[2].func
fc = func_coef
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
u, v, w = symbols('u, v, w', cls=Dummy)
a = Wild('a', exclude=[x(t), y(t), z(t), t])
b = Wild('b', exclude=[x(t), y(t), z(t), t])
c = Wild('c', exclude=[x(t), y(t), z(t), t])
f = Wild('f')
F1 = Wild('F1')
F2 = Wild('F2')
F3 = Wild('F3')
for i in range(3):
eqs = 0
for terms in Add.make_args(eq[i]):
eqs += terms/fc[i,func[i],1]
eq[i] = eqs
r1 = eq[0].match(diff(x(t),t) - a*y(t)*z(t))
r2 = eq[1].match(diff(y(t),t) - b*z(t)*x(t))
r3 = eq[2].match(diff(z(t),t) - c*x(t)*y(t))
if r1 and r2 and r3:
num1, den1 = r1[a].as_numer_denom()
num2, den2 = r2[b].as_numer_denom()
num3, den3 = r3[c].as_numer_denom()
if solve([num1*u-den1*(v-w), num2*v-den2*(w-u), num3*w-den3*(u-v)],[u, v]):
return 'type1'
r = eq[0].match(diff(x(t),t) - y(t)*z(t)*f)
if r:
r1 = collect_const(r[f]).match(a*f)
r2 = ((diff(y(t),t) - eq[1])/r1[f]).match(b*z(t)*x(t))
r3 = ((diff(z(t),t) - eq[2])/r1[f]).match(c*x(t)*y(t))
if r1 and r2 and r3:
num1, den1 = r1[a].as_numer_denom()
num2, den2 = r2[b].as_numer_denom()
num3, den3 = r3[c].as_numer_denom()
if solve([num1*u-den1*(v-w), num2*v-den2*(w-u), num3*w-den3*(u-v)],[u, v]):
return 'type2'
r = eq[0].match(diff(x(t),t) - (F2-F3))
if r:
r1 = collect_const(r[F2]).match(c*F2)
r1.update(collect_const(r[F3]).match(b*F3))
if r1:
if eq[1].has(r1[F2]) and not eq[1].has(r1[F3]):
r1[F2], r1[F3] = r1[F3], r1[F2]
r1[c], r1[b] = -r1[b], -r1[c]
r2 = eq[1].match(diff(y(t),t) - a*r1[F3] + r1[c]*F1)
if r2:
r3 = (eq[2] == diff(z(t),t) - r1[b]*r2[F1] + r2[a]*r1[F2])
if r1 and r2 and r3:
return 'type3'
r = eq[0].match(diff(x(t),t) - z(t)*F2 + y(t)*F3)
if r:
r1 = collect_const(r[F2]).match(c*F2)
r1.update(collect_const(r[F3]).match(b*F3))
if r1:
if eq[1].has(r1[F2]) and not eq[1].has(r1[F3]):
r1[F2], r1[F3] = r1[F3], r1[F2]
r1[c], r1[b] = -r1[b], -r1[c]
r2 = (diff(y(t),t) - eq[1]).match(a*x(t)*r1[F3] - r1[c]*z(t)*F1)
if r2:
r3 = (diff(z(t),t) - eq[2] == r1[b]*y(t)*r2[F1] - r2[a]*x(t)*r1[F2])
if r1 and r2 and r3:
return 'type4'
r = (diff(x(t),t) - eq[0]).match(x(t)*(F2 - F3))
if r:
r1 = collect_const(r[F2]).match(c*F2)
r1.update(collect_const(r[F3]).match(b*F3))
if r1:
if eq[1].has(r1[F2]) and not eq[1].has(r1[F3]):
r1[F2], r1[F3] = r1[F3], r1[F2]
r1[c], r1[b] = -r1[b], -r1[c]
r2 = (diff(y(t),t) - eq[1]).match(y(t)*(a*r1[F3] - r1[c]*F1))
if r2:
r3 = (diff(z(t),t) - eq[2] == z(t)*(r1[b]*r2[F1] - r2[a]*r1[F2]))
if r1 and r2 and r3:
return 'type5'
return None
def check_nonlinear_3eq_order2(eq, func, func_coef):
return None
def checksysodesol(eqs, sols, func=None):
r"""
Substitutes corresponding ``sols`` for each functions into each ``eqs`` and
checks that the result of substitutions for each equation is ``0``. The
equations and solutions passed can be any iterable.
This only works when each ``sols`` have one function only, like `x(t)` or `y(t)`.
For each function, ``sols`` can have a single solution or a list of solutions.
In most cases it will not be necessary to explicitly identify the function,
but if the function cannot be inferred from the original equation it
can be supplied through the ``func`` argument.
When a sequence of equations is passed, the same sequence is used to return
the result for each equation with each function substituted with corresponding
solutions.
It tries the following method to find zero equivalence for each equation:
Substitute the solutions for functions, like `x(t)` and `y(t)` into the
original equations containing those functions.
This function returns a tuple. The first item in the tuple is ``True`` if
the substitution results for each equation is ``0``, and ``False`` otherwise.
The second item in the tuple is what the substitution results in. Each element
of the ``list`` should always be ``0`` corresponding to each equation if the
first item is ``True``. Note that sometimes this function may return ``False``,
but with an expression that is identically equal to ``0``, instead of returning
``True``. This is because :py:meth:`~sympy.simplify.simplify.simplify` cannot
reduce the expression to ``0``. If an expression returned by each function
vanishes identically, then ``sols`` really is a solution to ``eqs``.
If this function seems to hang, it is probably because of a difficult simplification.
Examples
========
>>> from sympy import Eq, diff, symbols, sin, cos, exp, sqrt, S, Function
>>> from sympy.solvers.ode import checksysodesol
>>> C1, C2 = symbols('C1:3')
>>> t = symbols('t')
>>> x, y = symbols('x, y', cls=Function)
>>> eq = (Eq(diff(x(t),t), x(t) + y(t) + 17), Eq(diff(y(t),t), -2*x(t) + y(t) + 12))
>>> sol = [Eq(x(t), (C1*sin(sqrt(2)*t) + C2*cos(sqrt(2)*t))*exp(t) - S(5)/3),
... Eq(y(t), (sqrt(2)*C1*cos(sqrt(2)*t) - sqrt(2)*C2*sin(sqrt(2)*t))*exp(t) - S(46)/3)]
>>> checksysodesol(eq, sol)
(True, [0, 0])
>>> eq = (Eq(diff(x(t),t),x(t)*y(t)**4), Eq(diff(y(t),t),y(t)**3))
>>> sol = [Eq(x(t), C1*exp(-1/(4*(C2 + t)))), Eq(y(t), -sqrt(2)*sqrt(-1/(C2 + t))/2),
... Eq(x(t), C1*exp(-1/(4*(C2 + t)))), Eq(y(t), sqrt(2)*sqrt(-1/(C2 + t))/2)]
>>> checksysodesol(eq, sol)
(True, [0, 0])
"""
def _sympify(eq):
return list(map(sympify, eq if iterable(eq) else [eq]))
eqs = _sympify(eqs)
for i in range(len(eqs)):
if isinstance(eqs[i], Equality):
eqs[i] = eqs[i].lhs - eqs[i].rhs
if func is None:
funcs = []
for eq in eqs:
derivs = eq.atoms(Derivative)
func = set().union(*[d.atoms(AppliedUndef) for d in derivs])
for func_ in func:
funcs.append(func_)
funcs = list(set(funcs))
if not all(isinstance(func, AppliedUndef) and len(func.args) == 1 for func in funcs)\
and len({func.args for func in funcs})!=1:
raise ValueError("func must be a function of one variable, not %s" % func)
for sol in sols:
if len(sol.atoms(AppliedUndef)) != 1:
raise ValueError("solutions should have one function only")
if len(funcs) != len({sol.lhs for sol in sols}):
raise ValueError("number of solutions provided does not match the number of equations")
t = funcs[0].args[0]
dictsol = dict()
for sol in sols:
func = list(sol.atoms(AppliedUndef))[0]
if sol.rhs == func:
sol = sol.reversed
solved = sol.lhs == func and not sol.rhs.has(func)
if not solved:
rhs = solve(sol, func)
if not rhs:
raise NotImplementedError
else:
rhs = sol.rhs
dictsol[func] = rhs
checkeq = []
for eq in eqs:
for func in funcs:
eq = sub_func_doit(eq, func, dictsol[func])
ss = simplify(eq)
if ss != 0:
eq = ss.expand(force=True)
else:
eq = 0
checkeq.append(eq)
if len(set(checkeq)) == 1 and list(set(checkeq))[0] == 0:
return (True, checkeq)
else:
return (False, checkeq)
@vectorize(0)
def odesimp(eq, func, order, constants, hint):
r"""
Simplifies ODEs, including trying to solve for ``func`` and running
:py:meth:`~sympy.solvers.ode.constantsimp`.
It may use knowledge of the type of solution that the hint returns to
apply additional simplifications.
It also attempts to integrate any :py:class:`~sympy.integrals.Integral`\s
in the expression, if the hint is not an ``_Integral`` hint.
This function should have no effect on expressions returned by
:py:meth:`~sympy.solvers.ode.dsolve`, as
:py:meth:`~sympy.solvers.ode.dsolve` already calls
:py:meth:`~sympy.solvers.ode.odesimp`, but the individual hint functions
do not call :py:meth:`~sympy.solvers.ode.odesimp` (because the
:py:meth:`~sympy.solvers.ode.dsolve` wrapper does). Therefore, this
function is designed for mainly internal use.
Examples
========
>>> from sympy import sin, symbols, dsolve, pprint, Function
>>> from sympy.solvers.ode import odesimp
>>> x , u2, C1= symbols('x,u2,C1')
>>> f = Function('f')
>>> eq = dsolve(x*f(x).diff(x) - f(x) - x*sin(f(x)/x), f(x),
... hint='1st_homogeneous_coeff_subs_indep_div_dep_Integral',
... simplify=False)
>>> pprint(eq, wrap_line=False)
x
----
f(x)
/
|
| / 1 \
| -|u2 + -------|
| | /1 \|
| | sin|--||
| \ \u2//
log(f(x)) = log(C1) + | ---------------- d(u2)
| 2
| u2
|
/
>>> pprint(odesimp(eq, f(x), 1, {C1},
... hint='1st_homogeneous_coeff_subs_indep_div_dep'
... )) #doctest: +SKIP
x
--------- = C1
/f(x)\
tan|----|
\2*x /
"""
x = func.args[0]
f = func.func
C1 = get_numbered_constants(eq, num=1)
# First, integrate if the hint allows it.
eq = _handle_Integral(eq, func, order, hint)
if hint.startswith("nth_linear_euler_eq_nonhomogeneous"):
eq = simplify(eq)
if not isinstance(eq, Equality):
raise TypeError("eq should be an instance of Equality")
# Second, clean up the arbitrary constants.
# Right now, nth linear hints can put as many as 2*order constants in an
# expression. If that number grows with another hint, the third argument
# here should be raised accordingly, or constantsimp() rewritten to handle
# an arbitrary number of constants.
eq = constantsimp(eq, constants)
# Lastly, now that we have cleaned up the expression, try solving for func.
# When CRootOf is implemented in solve(), we will want to return a CRootOf
# every time instead of an Equality.
# Get the f(x) on the left if possible.
if eq.rhs == func and not eq.lhs.has(func):
eq = [Eq(eq.rhs, eq.lhs)]
# make sure we are working with lists of solutions in simplified form.
if eq.lhs == func and not eq.rhs.has(func):
# The solution is already solved
eq = [eq]
# special simplification of the rhs
if hint.startswith("nth_linear_constant_coeff"):
# Collect terms to make the solution look nice.
# This is also necessary for constantsimp to remove unnecessary
# terms from the particular solution from variation of parameters
#
# Collect is not behaving reliably here. The results for
# some linear constant-coefficient equations with repeated
# roots do not properly simplify all constants sometimes.
# 'collectterms' gives different orders sometimes, and results
# differ in collect based on that order. The
# sort-reverse trick fixes things, but may fail in the
# future. In addition, collect is splitting exponentials with
# rational powers for no reason. We have to do a match
# to fix this using Wilds.
global collectterms
try:
collectterms.sort(key=default_sort_key)
collectterms.reverse()
except Exception:
pass
assert len(eq) == 1 and eq[0].lhs == f(x)
sol = eq[0].rhs
sol = expand_mul(sol)
for i, reroot, imroot in collectterms:
sol = collect(sol, x**i*exp(reroot*x)*sin(abs(imroot)*x))
sol = collect(sol, x**i*exp(reroot*x)*cos(imroot*x))
for i, reroot, imroot in collectterms:
sol = collect(sol, x**i*exp(reroot*x))
del collectterms
# Collect is splitting exponentials with rational powers for
# no reason. We call powsimp to fix.
sol = powsimp(sol)
eq[0] = Eq(f(x), sol)
else:
# The solution is not solved, so try to solve it
try:
floats = any(i.is_Float for i in eq.atoms(Number))
eqsol = solve(eq, func, force=True, rational=False if floats else None)
if not eqsol:
raise NotImplementedError
except (NotImplementedError, PolynomialError):
eq = [eq]
else:
def _expand(expr):
numer, denom = expr.as_numer_denom()
if denom.is_Add:
return expr
else:
return powsimp(expr.expand(), combine='exp', deep=True)
# XXX: the rest of odesimp() expects each ``t`` to be in a
# specific normal form: rational expression with numerator
# expanded, but with combined exponential functions (at
# least in this setup all tests pass).
eq = [Eq(f(x), _expand(t)) for t in eqsol]
# special simplification of the lhs.
if hint.startswith("1st_homogeneous_coeff"):
for j, eqi in enumerate(eq):
newi = logcombine(eqi, force=True)
if isinstance(newi.lhs, log) and newi.rhs == 0:
newi = Eq(newi.lhs.args[0]/C1, C1)
eq[j] = newi
# We cleaned up the constants before solving to help the solve engine with
# a simpler expression, but the solved expression could have introduced
# things like -C1, so rerun constantsimp() one last time before returning.
for i, eqi in enumerate(eq):
eq[i] = constantsimp(eqi, constants)
eq[i] = constant_renumber(eq[i], 'C', 1, 2*order)
# If there is only 1 solution, return it;
# otherwise return the list of solutions.
if len(eq) == 1:
eq = eq[0]
return eq
def checkodesol(ode, sol, func=None, order='auto', solve_for_func=True):
r"""
Substitutes ``sol`` into ``ode`` and checks that the result is ``0``.
This only works when ``func`` is one function, like `f(x)`. ``sol`` can
be a single solution or a list of solutions. Each solution may be an
:py:class:`~sympy.core.relational.Equality` that the solution satisfies,
e.g. ``Eq(f(x), C1), Eq(f(x) + C1, 0)``; or simply an
:py:class:`~sympy.core.expr.Expr`, e.g. ``f(x) - C1``. In most cases it
will not be necessary to explicitly identify the function, but if the
function cannot be inferred from the original equation it can be supplied
through the ``func`` argument.
If a sequence of solutions is passed, the same sort of container will be
used to return the result for each solution.
It tries the following methods, in order, until it finds zero equivalence:
1. Substitute the solution for `f` in the original equation. This only
works if ``ode`` is solved for `f`. It will attempt to solve it first
unless ``solve_for_func == False``.
2. Take `n` derivatives of the solution, where `n` is the order of
``ode``, and check to see if that is equal to the solution. This only
works on exact ODEs.
3. Take the 1st, 2nd, ..., `n`\th derivatives of the solution, each time
solving for the derivative of `f` of that order (this will always be
possible because `f` is a linear operator). Then back substitute each
derivative into ``ode`` in reverse order.
This function returns a tuple. The first item in the tuple is ``True`` if
the substitution results in ``0``, and ``False`` otherwise. The second
item in the tuple is what the substitution results in. It should always
be ``0`` if the first item is ``True``. Sometimes this function will
return ``False`` even when an expression is identically equal to ``0``.
This happens when :py:meth:`~sympy.simplify.simplify.simplify` does not
reduce the expression to ``0``. If an expression returned by this
function vanishes identically, then ``sol`` really is a solution to
the ``ode``.
If this function seems to hang, it is probably because of a hard
simplification.
To use this function to test, test the first item of the tuple.
Examples
========
>>> from sympy import Eq, Function, checkodesol, symbols
>>> x, C1 = symbols('x,C1')
>>> f = Function('f')
>>> checkodesol(f(x).diff(x), Eq(f(x), C1))
(True, 0)
>>> assert checkodesol(f(x).diff(x), C1)[0]
>>> assert not checkodesol(f(x).diff(x), x)[0]
>>> checkodesol(f(x).diff(x, 2), x**2)
(False, 2)
"""
if not isinstance(ode, Equality):
ode = Eq(ode, 0)
if func is None:
try:
_, func = _preprocess(ode.lhs)
except ValueError:
funcs = [s.atoms(AppliedUndef) for s in (
sol if is_sequence(sol, set) else [sol])]
funcs = set().union(*funcs)
if len(funcs) != 1:
raise ValueError(
'must pass func arg to checkodesol for this case.')
func = funcs.pop()
if not isinstance(func, AppliedUndef) or len(func.args) != 1:
raise ValueError(
"func must be a function of one variable, not %s" % func)
if is_sequence(sol, set):
return type(sol)([checkodesol(ode, i, order=order, solve_for_func=solve_for_func) for i in sol])
if not isinstance(sol, Equality):
sol = Eq(func, sol)
elif sol.rhs == func:
sol = sol.reversed
if order == 'auto':
order = ode_order(ode, func)
solved = sol.lhs == func and not sol.rhs.has(func)
if solve_for_func and not solved:
rhs = solve(sol, func)
if rhs:
eqs = [Eq(func, t) for t in rhs]
if len(rhs) == 1:
eqs = eqs[0]
return checkodesol(ode, eqs, order=order,
solve_for_func=False)
s = True
testnum = 0
x = func.args[0]
while s:
if testnum == 0:
# First pass, try substituting a solved solution directly into the
# ODE. This has the highest chance of succeeding.
ode_diff = ode.lhs - ode.rhs
if sol.lhs == func:
s = sub_func_doit(ode_diff, func, sol.rhs)
else:
testnum += 1
continue
ss = simplify(s)
if ss:
# with the new numer_denom in power.py, if we do a simple
# expansion then testnum == 0 verifies all solutions.
s = ss.expand(force=True)
else:
s = 0
testnum += 1
elif testnum == 1:
# Second pass. If we cannot substitute f, try seeing if the nth
# derivative is equal, this will only work for odes that are exact,
# by definition.
s = simplify(
trigsimp(diff(sol.lhs, x, order) - diff(sol.rhs, x, order)) -
trigsimp(ode.lhs) + trigsimp(ode.rhs))
# s2 = simplify(
# diff(sol.lhs, x, order) - diff(sol.rhs, x, order) - \
# ode.lhs + ode.rhs)
testnum += 1
elif testnum == 2:
# Third pass. Try solving for df/dx and substituting that into the
# ODE. Thanks to Chris Smith for suggesting this method. Many of
# the comments below are his, too.
# The method:
# - Take each of 1..n derivatives of the solution.
# - Solve each nth derivative for d^(n)f/dx^(n)
# (the differential of that order)
# - Back substitute into the ODE in decreasing order
# (i.e., n, n-1, ...)
# - Check the result for zero equivalence
if sol.lhs == func and not sol.rhs.has(func):
diffsols = {0: sol.rhs}
elif sol.rhs == func and not sol.lhs.has(func):
diffsols = {0: sol.lhs}
else:
diffsols = {}
sol = sol.lhs - sol.rhs
for i in range(1, order + 1):
# Differentiation is a linear operator, so there should always
# be 1 solution. Nonetheless, we test just to make sure.
# We only need to solve once. After that, we automatically
# have the solution to the differential in the order we want.
if i == 1:
ds = sol.diff(x)
try:
sdf = solve(ds, func.diff(x, i))
if not sdf:
raise NotImplementedError
except NotImplementedError:
testnum += 1
break
else:
diffsols[i] = sdf[0]
else:
# This is what the solution says df/dx should be.
diffsols[i] = diffsols[i - 1].diff(x)
# Make sure the above didn't fail.
if testnum > 2:
continue
else:
# Substitute it into ODE to check for self consistency.
lhs, rhs = ode.lhs, ode.rhs
for i in range(order, -1, -1):
if i == 0 and 0 not in diffsols:
# We can only substitute f(x) if the solution was
# solved for f(x).
break
lhs = sub_func_doit(lhs, func.diff(x, i), diffsols[i])
rhs = sub_func_doit(rhs, func.diff(x, i), diffsols[i])
ode_or_bool = Eq(lhs, rhs)
ode_or_bool = simplify(ode_or_bool)
if isinstance(ode_or_bool, (bool, BooleanAtom)):
if ode_or_bool:
lhs = rhs = S.Zero
else:
lhs = ode_or_bool.lhs
rhs = ode_or_bool.rhs
# No sense in overworking simplify -- just prove that the
# numerator goes to zero
num = trigsimp((lhs - rhs).as_numer_denom()[0])
# since solutions are obtained using force=True we test
# using the same level of assumptions
## replace function with dummy so assumptions will work
_func = Dummy('func')
num = num.subs(func, _func)
## posify the expression
num, reps = posify(num)
s = simplify(num).xreplace(reps).xreplace({_func: func})
testnum += 1
else:
break
if not s:
return (True, s)
elif s is True: # The code above never was able to change s
raise NotImplementedError("Unable to test if " + str(sol) +
" is a solution to " + str(ode) + ".")
else:
return (False, s)
def ode_sol_simplicity(sol, func, trysolving=True):
r"""
Returns an extended integer representing how simple a solution to an ODE
is.
The following things are considered, in order from most simple to least:
- ``sol`` is solved for ``func``.
- ``sol`` is not solved for ``func``, but can be if passed to solve (e.g.,
a solution returned by ``dsolve(ode, func, simplify=False``).
- If ``sol`` is not solved for ``func``, then base the result on the
length of ``sol``, as computed by ``len(str(sol))``.
- If ``sol`` has any unevaluated :py:class:`~sympy.integrals.Integral`\s,
this will automatically be considered less simple than any of the above.
This function returns an integer such that if solution A is simpler than
solution B by above metric, then ``ode_sol_simplicity(sola, func) <
ode_sol_simplicity(solb, func)``.
Currently, the following are the numbers returned, but if the heuristic is
ever improved, this may change. Only the ordering is guaranteed.
+----------------------------------------------+-------------------+
| Simplicity | Return |
+==============================================+===================+
| ``sol`` solved for ``func`` | ``-2`` |
+----------------------------------------------+-------------------+
| ``sol`` not solved for ``func`` but can be | ``-1`` |
+----------------------------------------------+-------------------+
| ``sol`` is not solved nor solvable for | ``len(str(sol))`` |
| ``func`` | |
+----------------------------------------------+-------------------+
| ``sol`` contains an | ``oo`` |
| :py:class:`~sympy.integrals.Integral` | |
+----------------------------------------------+-------------------+
``oo`` here means the SymPy infinity, which should compare greater than
any integer.
If you already know :py:meth:`~sympy.solvers.solvers.solve` cannot solve
``sol``, you can use ``trysolving=False`` to skip that step, which is the
only potentially slow step. For example,
:py:meth:`~sympy.solvers.ode.dsolve` with the ``simplify=False`` flag
should do this.
If ``sol`` is a list of solutions, if the worst solution in the list
returns ``oo`` it returns that, otherwise it returns ``len(str(sol))``,
that is, the length of the string representation of the whole list.
Examples
========
This function is designed to be passed to ``min`` as the key argument,
such as ``min(listofsolutions, key=lambda i: ode_sol_simplicity(i,
f(x)))``.
>>> from sympy import symbols, Function, Eq, tan, cos, sqrt, Integral
>>> from sympy.solvers.ode import ode_sol_simplicity
>>> x, C1, C2 = symbols('x, C1, C2')
>>> f = Function('f')
>>> ode_sol_simplicity(Eq(f(x), C1*x**2), f(x))
-2
>>> ode_sol_simplicity(Eq(x**2 + f(x), C1), f(x))
-1
>>> ode_sol_simplicity(Eq(f(x), C1*Integral(2*x, x)), f(x))
oo
>>> eq1 = Eq(f(x)/tan(f(x)/(2*x)), C1)
>>> eq2 = Eq(f(x)/tan(f(x)/(2*x) + f(x)), C2)
>>> [ode_sol_simplicity(eq, f(x)) for eq in [eq1, eq2]]
[28, 35]
>>> min([eq1, eq2], key=lambda i: ode_sol_simplicity(i, f(x)))
Eq(f(x)/tan(f(x)/(2*x)), C1)
"""
# TODO: if two solutions are solved for f(x), we still want to be
# able to get the simpler of the two
# See the docstring for the coercion rules. We check easier (faster)
# things here first, to save time.
if iterable(sol):
# See if there are Integrals
for i in sol:
if ode_sol_simplicity(i, func, trysolving=trysolving) == oo:
return oo
return len(str(sol))
if sol.has(Integral):
return oo
# Next, try to solve for func. This code will change slightly when CRootOf
# is implemented in solve(). Probably a CRootOf solution should fall
# somewhere between a normal solution and an unsolvable expression.
# First, see if they are already solved
if sol.lhs == func and not sol.rhs.has(func) or \
sol.rhs == func and not sol.lhs.has(func):
return -2
# We are not so lucky, try solving manually
if trysolving:
try:
sols = solve(sol, func)
if not sols:
raise NotImplementedError
except NotImplementedError:
pass
else:
return -1
# Finally, a naive computation based on the length of the string version
# of the expression. This may favor combined fractions because they
# will not have duplicate denominators, and may slightly favor expressions
# with fewer additions and subtractions, as those are separated by spaces
# by the printer.
# Additional ideas for simplicity heuristics are welcome, like maybe
# checking if a equation has a larger domain, or if constantsimp has
# introduced arbitrary constants numbered higher than the order of a
# given ODE that sol is a solution of.
return len(str(sol))
def _get_constant_subexpressions(expr, Cs):
Cs = set(Cs)
Ces = []
def _recursive_walk(expr):
expr_syms = expr.free_symbols
if len(expr_syms) > 0 and expr_syms.issubset(Cs):
Ces.append(expr)
else:
if expr.func == exp:
expr = expr.expand(mul=True)
if expr.func in (Add, Mul):
d = sift(expr.args, lambda i : i.free_symbols.issubset(Cs))
if len(d[True]) > 1:
x = expr.func(*d[True])
if not x.is_number:
Ces.append(x)
elif isinstance(expr, Integral):
if expr.free_symbols.issubset(Cs) and \
all(len(x) == 3 for x in expr.limits):
Ces.append(expr)
for i in expr.args:
_recursive_walk(i)
return
_recursive_walk(expr)
return Ces
def __remove_linear_redundancies(expr, Cs):
cnts = {i: expr.count(i) for i in Cs}
Cs = [i for i in Cs if cnts[i] > 0]
def _linear(expr):
if isinstance(expr, Add):
xs = [i for i in Cs if expr.count(i)==cnts[i] \
and 0 == expr.diff(i, 2)]
d = {}
for x in xs:
y = expr.diff(x)
if y not in d:
d[y]=[]
d[y].append(x)
for y in d:
if len(d[y]) > 1:
d[y].sort(key=str)
for x in d[y][1:]:
expr = expr.subs(x, 0)
return expr
def _recursive_walk(expr):
if len(expr.args) != 0:
expr = expr.func(*[_recursive_walk(i) for i in expr.args])
expr = _linear(expr)
return expr
if isinstance(expr, Equality):
lhs, rhs = [_recursive_walk(i) for i in expr.args]
f = lambda i: isinstance(i, Number) or i in Cs
if isinstance(lhs, Symbol) and lhs in Cs:
rhs, lhs = lhs, rhs
if lhs.func in (Add, Symbol) and rhs.func in (Add, Symbol):
dlhs = sift([lhs] if isinstance(lhs, AtomicExpr) else lhs.args, f)
drhs = sift([rhs] if isinstance(rhs, AtomicExpr) else rhs.args, f)
for i in [True, False]:
for hs in [dlhs, drhs]:
if i not in hs:
hs[i] = [0]
# this calculation can be simplified
lhs = Add(*dlhs[False]) - Add(*drhs[False])
rhs = Add(*drhs[True]) - Add(*dlhs[True])
elif lhs.func in (Mul, Symbol) and rhs.func in (Mul, Symbol):
dlhs = sift([lhs] if isinstance(lhs, AtomicExpr) else lhs.args, f)
if True in dlhs:
if False not in dlhs:
dlhs[False] = [1]
lhs = Mul(*dlhs[False])
rhs = rhs/Mul(*dlhs[True])
return Eq(lhs, rhs)
else:
return _recursive_walk(expr)
@vectorize(0)
def constantsimp(expr, constants):
r"""
Simplifies an expression with arbitrary constants in it.
This function is written specifically to work with
:py:meth:`~sympy.solvers.ode.dsolve`, and is not intended for general use.
Simplification is done by "absorbing" the arbitrary constants into other
arbitrary constants, numbers, and symbols that they are not independent
of.
The symbols must all have the same name with numbers after it, for
example, ``C1``, ``C2``, ``C3``. The ``symbolname`` here would be
'``C``', the ``startnumber`` would be 1, and the ``endnumber`` would be 3.
If the arbitrary constants are independent of the variable ``x``, then the
independent symbol would be ``x``. There is no need to specify the
dependent function, such as ``f(x)``, because it already has the
independent symbol, ``x``, in it.
Because terms are "absorbed" into arbitrary constants and because
constants are renumbered after simplifying, the arbitrary constants in
expr are not necessarily equal to the ones of the same name in the
returned result.
If two or more arbitrary constants are added, multiplied, or raised to the
power of each other, they are first absorbed together into a single
arbitrary constant. Then the new constant is combined into other terms if
necessary.
Absorption of constants is done with limited assistance:
1. terms of :py:class:`~sympy.core.add.Add`\s are collected to try join
constants so `e^x (C_1 \cos(x) + C_2 \cos(x))` will simplify to `e^x
C_1 \cos(x)`;
2. powers with exponents that are :py:class:`~sympy.core.add.Add`\s are
expanded so `e^{C_1 + x}` will be simplified to `C_1 e^x`.
Use :py:meth:`~sympy.solvers.ode.constant_renumber` to renumber constants
after simplification or else arbitrary numbers on constants may appear,
e.g. `C_1 + C_3 x`.
In rare cases, a single constant can be "simplified" into two constants.
Every differential equation solution should have as many arbitrary
constants as the order of the differential equation. The result here will
be technically correct, but it may, for example, have `C_1` and `C_2` in
an expression, when `C_1` is actually equal to `C_2`. Use your discretion
in such situations, and also take advantage of the ability to use hints in
:py:meth:`~sympy.solvers.ode.dsolve`.
Examples
========
>>> from sympy import symbols
>>> from sympy.solvers.ode import constantsimp
>>> C1, C2, C3, x, y = symbols('C1, C2, C3, x, y')
>>> constantsimp(2*C1*x, {C1, C2, C3})
C1*x
>>> constantsimp(C1 + 2 + x, {C1, C2, C3})
C1 + x
>>> constantsimp(C1*C2 + 2 + C2 + C3*x, {C1, C2, C3})
C1 + C3*x
"""
# This function works recursively. The idea is that, for Mul,
# Add, Pow, and Function, if the class has a constant in it, then
# we can simplify it, which we do by recursing down and
# simplifying up. Otherwise, we can skip that part of the
# expression.
Cs = constants
orig_expr = expr
constant_subexprs = _get_constant_subexpressions(expr, Cs)
for xe in constant_subexprs:
xes = list(xe.free_symbols)
if not xes:
continue
if all([expr.count(c) == xe.count(c) for c in xes]):
xes.sort(key=str)
expr = expr.subs(xe, xes[0])
# try to perform common sub-expression elimination of constant terms
try:
commons, rexpr = cse(expr)
commons.reverse()
rexpr = rexpr[0]
for s in commons:
cs = list(s[1].atoms(Symbol))
if len(cs) == 1 and cs[0] in Cs and \
cs[0] not in rexpr.atoms(Symbol) and \
not any(cs[0] in ex for ex in commons if ex != s):
rexpr = rexpr.subs(s[0], cs[0])
else:
rexpr = rexpr.subs(*s)
expr = rexpr
except Exception:
pass
expr = __remove_linear_redundancies(expr, Cs)
def _conditional_term_factoring(expr):
new_expr = terms_gcd(expr, clear=False, deep=True, expand=False)
# we do not want to factor exponentials, so handle this separately
if new_expr.is_Mul:
infac = False
asfac = False
for m in new_expr.args:
if isinstance(m, exp):
asfac = True
elif m.is_Add:
infac = any(isinstance(fi, exp) for t in m.args
for fi in Mul.make_args(t))
if asfac and infac:
new_expr = expr
break
return new_expr
expr = _conditional_term_factoring(expr)
# call recursively if more simplification is possible
if orig_expr != expr:
return constantsimp(expr, Cs)
return expr
def constant_renumber(expr, symbolname, startnumber, endnumber):
r"""
Renumber arbitrary constants in ``expr`` to have numbers 1 through `N`
where `N` is ``endnumber - startnumber + 1`` at most.
In the process, this reorders expression terms in a standard way.
This is a simple function that goes through and renumbers any
:py:class:`~sympy.core.symbol.Symbol` with a name in the form ``symbolname
+ num`` where ``num`` is in the range from ``startnumber`` to
``endnumber``.
Symbols are renumbered based on ``.sort_key()``, so they should be
numbered roughly in the order that they appear in the final, printed
expression. Note that this ordering is based in part on hashes, so it can
produce different results on different machines.
The structure of this function is very similar to that of
:py:meth:`~sympy.solvers.ode.constantsimp`.
Examples
========
>>> from sympy import symbols, Eq, pprint
>>> from sympy.solvers.ode import constant_renumber
>>> x, C0, C1, C2, C3, C4 = symbols('x,C:5')
Only constants in the given range (inclusive) are renumbered;
the renumbering always starts from 1:
>>> constant_renumber(C1 + C3 + C4, 'C', 1, 3)
C1 + C2 + C4
>>> constant_renumber(C0 + C1 + C3 + C4, 'C', 2, 4)
C0 + 2*C1 + C2
>>> constant_renumber(C0 + 2*C1 + C2, 'C', 0, 1)
C1 + 3*C2
>>> pprint(C2 + C1*x + C3*x**2)
2
C1*x + C2 + C3*x
>>> pprint(constant_renumber(C2 + C1*x + C3*x**2, 'C', 1, 3))
2
C1 + C2*x + C3*x
"""
if type(expr) in (set, list, tuple):
return type(expr)(
[constant_renumber(i, symbolname=symbolname, startnumber=startnumber, endnumber=endnumber)
for i in expr]
)
global newstartnumber
newstartnumber = 1
constants_found = [None]*(endnumber + 2)
constantsymbols = [Symbol(
symbolname + "%d" % t) for t in range(startnumber,
endnumber + 1)]
# make a mapping to send all constantsymbols to S.One and use
# that to make sure that term ordering is not dependent on
# the indexed value of C
C_1 = [(ci, S.One) for ci in constantsymbols]
sort_key=lambda arg: default_sort_key(arg.subs(C_1))
def _constant_renumber(expr):
r"""
We need to have an internal recursive function so that
newstartnumber maintains its values throughout recursive calls.
"""
global newstartnumber
if isinstance(expr, Equality):
return Eq(
_constant_renumber(expr.lhs),
_constant_renumber(expr.rhs))
if type(expr) not in (Mul, Add, Pow) and not expr.is_Function and \
not expr.has(*constantsymbols):
# Base case, as above. Hope there aren't constants inside
# of some other class, because they won't be renumbered.
return expr
elif expr.is_Piecewise:
return expr
elif expr in constantsymbols:
if expr not in constants_found:
constants_found[newstartnumber] = expr
newstartnumber += 1
return expr
elif expr.is_Function or expr.is_Pow or isinstance(expr, Tuple):
return expr.func(
*[_constant_renumber(x) for x in expr.args])
else:
sortedargs = list(expr.args)
sortedargs.sort(key=sort_key)
return expr.func(*[_constant_renumber(x) for x in sortedargs])
expr = _constant_renumber(expr)
# Renumbering happens here
newconsts = symbols('C1:%d' % newstartnumber)
expr = expr.subs(zip(constants_found[1:], newconsts), simultaneous=True)
return expr
def _handle_Integral(expr, func, order, hint):
r"""
Converts a solution with Integrals in it into an actual solution.
For most hints, this simply runs ``expr.doit()``.
"""
global y
x = func.args[0]
f = func.func
if hint == "1st_exact":
sol = (expr.doit()).subs(y, f(x))
del y
elif hint == "1st_exact_Integral":
sol = Eq(Subs(expr.lhs, y, f(x)), expr.rhs)
del y
elif hint == "nth_linear_constant_coeff_homogeneous":
sol = expr
elif not hint.endswith("_Integral"):
sol = expr.doit()
else:
sol = expr
return sol
# FIXME: replace the general solution in the docstring with
# dsolve(equation, hint='1st_exact_Integral'). You will need to be able
# to have assumptions on P and Q that dP/dy = dQ/dx.
def ode_1st_exact(eq, func, order, match):
r"""
Solves 1st order exact ordinary differential equations.
A 1st order differential equation is called exact if it is the total
differential of a function. That is, the differential equation
.. math:: P(x, y) \,\partial{}x + Q(x, y) \,\partial{}y = 0
is exact if there is some function `F(x, y)` such that `P(x, y) =
\partial{}F/\partial{}x` and `Q(x, y) = \partial{}F/\partial{}y`. It can
be shown that a necessary and sufficient condition for a first order ODE
to be exact is that `\partial{}P/\partial{}y = \partial{}Q/\partial{}x`.
Then, the solution will be as given below::
>>> from sympy import Function, Eq, Integral, symbols, pprint
>>> x, y, t, x0, y0, C1= symbols('x,y,t,x0,y0,C1')
>>> P, Q, F= map(Function, ['P', 'Q', 'F'])
>>> pprint(Eq(Eq(F(x, y), Integral(P(t, y), (t, x0, x)) +
... Integral(Q(x0, t), (t, y0, y))), C1))
x y
/ /
| |
F(x, y) = | P(t, y) dt + | Q(x0, t) dt = C1
| |
/ /
x0 y0
Where the first partials of `P` and `Q` exist and are continuous in a
simply connected region.
A note: SymPy currently has no way to represent inert substitution on an
expression, so the hint ``1st_exact_Integral`` will return an integral
with `dy`. This is supposed to represent the function that you are
solving for.
Examples
========
>>> from sympy import Function, dsolve, cos, sin
>>> from sympy.abc import x
>>> f = Function('f')
>>> dsolve(cos(f(x)) - (x*sin(f(x)) - f(x)**2)*f(x).diff(x),
... f(x), hint='1st_exact')
Eq(x*cos(f(x)) + f(x)**3/3, C1)
References
==========
- https://en.wikipedia.org/wiki/Exact_differential_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 73
# indirect doctest
"""
x = func.args[0]
f = func.func
r = match # d+e*diff(f(x),x)
e = r[r['e']]
d = r[r['d']]
global y # This is the only way to pass dummy y to _handle_Integral
y = r['y']
C1 = get_numbered_constants(eq, num=1)
# Refer Joel Moses, "Symbolic Integration - The Stormy Decade",
# Communications of the ACM, Volume 14, Number 8, August 1971, pp. 558
# which gives the method to solve an exact differential equation.
sol = Integral(d, x) + Integral((e - (Integral(d, x).diff(y))), y)
return Eq(sol, C1)
def ode_1st_homogeneous_coeff_best(eq, func, order, match):
r"""
Returns the best solution to an ODE from the two hints
``1st_homogeneous_coeff_subs_dep_div_indep`` and
``1st_homogeneous_coeff_subs_indep_div_dep``.
This is as determined by :py:meth:`~sympy.solvers.ode.ode_sol_simplicity`.
See the
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_indep_div_dep`
and
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_dep_div_indep`
docstrings for more information on these hints. Note that there is no
``ode_1st_homogeneous_coeff_best_Integral`` hint.
Examples
========
>>> from sympy import Function, dsolve, pprint
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(2*x*f(x) + (x**2 + f(x)**2)*f(x).diff(x), f(x),
... hint='1st_homogeneous_coeff_best', simplify=False))
/ 2 \
| 3*x |
log|----- + 1|
| 2 |
\f (x) /
log(f(x)) = log(C1) - --------------
3
References
==========
- https://en.wikipedia.org/wiki/Homogeneous_differential_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 59
# indirect doctest
"""
# There are two substitutions that solve the equation, u1=y/x and u2=x/y
# They produce different integrals, so try them both and see which
# one is easier.
sol1 = ode_1st_homogeneous_coeff_subs_indep_div_dep(eq,
func, order, match)
sol2 = ode_1st_homogeneous_coeff_subs_dep_div_indep(eq,
func, order, match)
simplify = match.get('simplify', True)
if simplify:
# why is odesimp called here? Should it be at the usual spot?
constants = sol1.free_symbols.difference(eq.free_symbols)
sol1 = odesimp(
sol1, func, order, constants,
"1st_homogeneous_coeff_subs_indep_div_dep")
constants = sol2.free_symbols.difference(eq.free_symbols)
sol2 = odesimp(
sol2, func, order, constants,
"1st_homogeneous_coeff_subs_dep_div_indep")
return min([sol1, sol2], key=lambda x: ode_sol_simplicity(x, func,
trysolving=not simplify))
def ode_1st_homogeneous_coeff_subs_dep_div_indep(eq, func, order, match):
r"""
Solves a 1st order differential equation with homogeneous coefficients
using the substitution `u_1 = \frac{\text{<dependent
variable>}}{\text{<independent variable>}}`.
This is a differential equation
.. math:: P(x, y) + Q(x, y) dy/dx = 0
such that `P` and `Q` are homogeneous and of the same order. A function
`F(x, y)` is homogeneous of order `n` if `F(x t, y t) = t^n F(x, y)`.
Equivalently, `F(x, y)` can be rewritten as `G(y/x)` or `H(x/y)`. See
also the docstring of :py:meth:`~sympy.solvers.ode.homogeneous_order`.
If the coefficients `P` and `Q` in the differential equation above are
homogeneous functions of the same order, then it can be shown that the
substitution `y = u_1 x` (i.e. `u_1 = y/x`) will turn the differential
equation into an equation separable in the variables `x` and `u`. If
`h(u_1)` is the function that results from making the substitution `u_1 =
f(x)/x` on `P(x, f(x))` and `g(u_2)` is the function that results from the
substitution on `Q(x, f(x))` in the differential equation `P(x, f(x)) +
Q(x, f(x)) f'(x) = 0`, then the general solution is::
>>> from sympy import Function, dsolve, pprint
>>> from sympy.abc import x
>>> f, g, h = map(Function, ['f', 'g', 'h'])
>>> genform = g(f(x)/x) + h(f(x)/x)*f(x).diff(x)
>>> pprint(genform)
/f(x)\ /f(x)\ d
g|----| + h|----|*--(f(x))
\ x / \ x / dx
>>> pprint(dsolve(genform, f(x),
... hint='1st_homogeneous_coeff_subs_dep_div_indep_Integral'))
f(x)
----
x
/
|
| -h(u1)
log(x) = C1 + | ---------------- d(u1)
| u1*h(u1) + g(u1)
|
/
Where `u_1 h(u_1) + g(u_1) \ne 0` and `x \ne 0`.
See also the docstrings of
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_best` and
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_indep_div_dep`.
Examples
========
>>> from sympy import Function, dsolve
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(2*x*f(x) + (x**2 + f(x)**2)*f(x).diff(x), f(x),
... hint='1st_homogeneous_coeff_subs_dep_div_indep', simplify=False))
/ 3 \
|3*f(x) f (x)|
log|------ + -----|
| x 3 |
\ x /
log(x) = log(C1) - -------------------
3
References
==========
- https://en.wikipedia.org/wiki/Homogeneous_differential_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 59
# indirect doctest
"""
x = func.args[0]
f = func.func
u = Dummy('u')
u1 = Dummy('u1') # u1 == f(x)/x
r = match # d+e*diff(f(x),x)
C1 = get_numbered_constants(eq, num=1)
xarg = match.get('xarg', 0)
yarg = match.get('yarg', 0)
int = Integral(
(-r[r['e']]/(r[r['d']] + u1*r[r['e']])).subs({x: 1, r['y']: u1}),
(u1, None, f(x)/x))
sol = logcombine(Eq(log(x), int + log(C1)), force=True)
sol = sol.subs(f(x), u).subs(((u, u - yarg), (x, x - xarg), (u, f(x))))
return sol
def ode_1st_homogeneous_coeff_subs_indep_div_dep(eq, func, order, match):
r"""
Solves a 1st order differential equation with homogeneous coefficients
using the substitution `u_2 = \frac{\text{<independent
variable>}}{\text{<dependent variable>}}`.
This is a differential equation
.. math:: P(x, y) + Q(x, y) dy/dx = 0
such that `P` and `Q` are homogeneous and of the same order. A function
`F(x, y)` is homogeneous of order `n` if `F(x t, y t) = t^n F(x, y)`.
Equivalently, `F(x, y)` can be rewritten as `G(y/x)` or `H(x/y)`. See
also the docstring of :py:meth:`~sympy.solvers.ode.homogeneous_order`.
If the coefficients `P` and `Q` in the differential equation above are
homogeneous functions of the same order, then it can be shown that the
substitution `x = u_2 y` (i.e. `u_2 = x/y`) will turn the differential
equation into an equation separable in the variables `y` and `u_2`. If
`h(u_2)` is the function that results from making the substitution `u_2 =
x/f(x)` on `P(x, f(x))` and `g(u_2)` is the function that results from the
substitution on `Q(x, f(x))` in the differential equation `P(x, f(x)) +
Q(x, f(x)) f'(x) = 0`, then the general solution is:
>>> from sympy import Function, dsolve, pprint
>>> from sympy.abc import x
>>> f, g, h = map(Function, ['f', 'g', 'h'])
>>> genform = g(x/f(x)) + h(x/f(x))*f(x).diff(x)
>>> pprint(genform)
/ x \ / x \ d
g|----| + h|----|*--(f(x))
\f(x)/ \f(x)/ dx
>>> pprint(dsolve(genform, f(x),
... hint='1st_homogeneous_coeff_subs_indep_div_dep_Integral'))
x
----
f(x)
/
|
| -g(u2)
| ---------------- d(u2)
| u2*g(u2) + h(u2)
|
/
<BLANKLINE>
f(x) = C1*e
Where `u_2 g(u_2) + h(u_2) \ne 0` and `f(x) \ne 0`.
See also the docstrings of
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_best` and
:py:meth:`~sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_dep_div_indep`.
Examples
========
>>> from sympy import Function, pprint, dsolve
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(2*x*f(x) + (x**2 + f(x)**2)*f(x).diff(x), f(x),
... hint='1st_homogeneous_coeff_subs_indep_div_dep',
... simplify=False))
/ 2 \
| 3*x |
log|----- + 1|
| 2 |
\f (x) /
log(f(x)) = log(C1) - --------------
3
References
==========
- https://en.wikipedia.org/wiki/Homogeneous_differential_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 59
# indirect doctest
"""
x = func.args[0]
f = func.func
u = Dummy('u')
u2 = Dummy('u2') # u2 == x/f(x)
r = match # d+e*diff(f(x),x)
C1 = get_numbered_constants(eq, num=1)
xarg = match.get('xarg', 0) # If xarg present take xarg, else zero
yarg = match.get('yarg', 0) # If yarg present take yarg, else zero
int = Integral(
simplify(
(-r[r['d']]/(r[r['e']] + u2*r[r['d']])).subs({x: u2, r['y']: 1})),
(u2, None, x/f(x)))
sol = logcombine(Eq(log(f(x)), int + log(C1)), force=True)
sol = sol.subs(f(x), u).subs(((u, u - yarg), (x, x - xarg), (u, f(x))))
return sol
# XXX: Should this function maybe go somewhere else?
def homogeneous_order(eq, *symbols):
r"""
Returns the order `n` if `g` is homogeneous and ``None`` if it is not
homogeneous.
Determines if a function is homogeneous and if so of what order. A
function `f(x, y, \cdots)` is homogeneous of order `n` if `f(t x, t y,
\cdots) = t^n f(x, y, \cdots)`.
If the function is of two variables, `F(x, y)`, then `f` being homogeneous
of any order is equivalent to being able to rewrite `F(x, y)` as `G(x/y)`
or `H(y/x)`. This fact is used to solve 1st order ordinary differential
equations whose coefficients are homogeneous of the same order (see the
docstrings of
:py:meth:`~solvers.ode.ode_1st_homogeneous_coeff_subs_dep_div_indep` and
:py:meth:`~solvers.ode.ode_1st_homogeneous_coeff_subs_indep_div_dep`).
Symbols can be functions, but every argument of the function must be a
symbol, and the arguments of the function that appear in the expression
must match those given in the list of symbols. If a declared function
appears with different arguments than given in the list of symbols,
``None`` is returned.
Examples
========
>>> from sympy import Function, homogeneous_order, sqrt
>>> from sympy.abc import x, y
>>> f = Function('f')
>>> homogeneous_order(f(x), f(x)) is None
True
>>> homogeneous_order(f(x,y), f(y, x), x, y) is None
True
>>> homogeneous_order(f(x), f(x), x)
1
>>> homogeneous_order(x**2*f(x)/sqrt(x**2+f(x)**2), x, f(x))
2
>>> homogeneous_order(x**2+f(x), x, f(x)) is None
True
"""
if not symbols:
raise ValueError("homogeneous_order: no symbols were given.")
symset = set(symbols)
eq = sympify(eq)
# The following are not supported
if eq.has(Order, Derivative):
return None
# These are all constants
if (eq.is_Number or
eq.is_NumberSymbol or
eq.is_number
):
return S.Zero
# Replace all functions with dummy variables
dum = numbered_symbols(prefix='d', cls=Dummy)
newsyms = set()
for i in [j for j in symset if getattr(j, 'is_Function')]:
iargs = set(i.args)
if iargs.difference(symset):
return None
else:
dummyvar = next(dum)
eq = eq.subs(i, dummyvar)
symset.remove(i)
newsyms.add(dummyvar)
symset.update(newsyms)
if not eq.free_symbols & symset:
return None
# assuming order of a nested function can only be equal to zero
if isinstance(eq, Function):
return None if homogeneous_order(
eq.args[0], *tuple(symset)) != 0 else S.Zero
# make the replacement of x with x*t and see if t can be factored out
t = Dummy('t', positive=True) # It is sufficient that t > 0
eqs = separatevars(eq.subs([(i, t*i) for i in symset]), [t], dict=True)[t]
if eqs is S.One:
return S.Zero # there was no term with only t
i, d = eqs.as_independent(t, as_Add=False)
b, e = d.as_base_exp()
if b == t:
return e
def ode_1st_linear(eq, func, order, match):
r"""
Solves 1st order linear differential equations.
These are differential equations of the form
.. math:: dy/dx + P(x) y = Q(x)\text{.}
These kinds of differential equations can be solved in a general way. The
integrating factor `e^{\int P(x) \,dx}` will turn the equation into a
separable equation. The general solution is::
>>> from sympy import Function, dsolve, Eq, pprint, diff, sin
>>> from sympy.abc import x
>>> f, P, Q = map(Function, ['f', 'P', 'Q'])
>>> genform = Eq(f(x).diff(x) + P(x)*f(x), Q(x))
>>> pprint(genform)
d
P(x)*f(x) + --(f(x)) = Q(x)
dx
>>> pprint(dsolve(genform, f(x), hint='1st_linear_Integral'))
/ / \
| | |
| | / | /
| | | | |
| | | P(x) dx | - | P(x) dx
| | | | |
| | / | /
f(x) = |C1 + | Q(x)*e dx|*e
| | |
\ / /
Examples
========
>>> f = Function('f')
>>> pprint(dsolve(Eq(x*diff(f(x), x) - f(x), x**2*sin(x)),
... f(x), '1st_linear'))
f(x) = x*(C1 - cos(x))
References
==========
- https://en.wikipedia.org/wiki/Linear_differential_equation#First_order_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 92
# indirect doctest
"""
x = func.args[0]
f = func.func
r = match # a*diff(f(x),x) + b*f(x) + c
C1 = get_numbered_constants(eq, num=1)
t = exp(Integral(r[r['b']]/r[r['a']], x))
tt = Integral(t*(-r[r['c']]/r[r['a']]), x)
f = match.get('u', f(x)) # take almost-linear u if present, else f(x)
return Eq(f, (tt + C1)/t)
def ode_Bernoulli(eq, func, order, match):
r"""
Solves Bernoulli differential equations.
These are equations of the form
.. math:: dy/dx + P(x) y = Q(x) y^n\text{, }n \ne 1`\text{.}
The substitution `w = 1/y^{1-n}` will transform an equation of this form
into one that is linear (see the docstring of
:py:meth:`~sympy.solvers.ode.ode_1st_linear`). The general solution is::
>>> from sympy import Function, dsolve, Eq, pprint
>>> from sympy.abc import x, n
>>> f, P, Q = map(Function, ['f', 'P', 'Q'])
>>> genform = Eq(f(x).diff(x) + P(x)*f(x), Q(x)*f(x)**n)
>>> pprint(genform)
d n
P(x)*f(x) + --(f(x)) = Q(x)*f (x)
dx
>>> pprint(dsolve(genform, f(x), hint='Bernoulli_Integral')) #doctest: +SKIP
1
----
1 - n
// / \ \
|| | | |
|| | / | / |
|| | | | | |
|| | (1 - n)* | P(x) dx | (-1 + n)* | P(x) dx|
|| | | | | |
|| | / | / |
f(x) = ||C1 + (-1 + n)* | -Q(x)*e dx|*e |
|| | | |
\\ / / /
Note that the equation is separable when `n = 1` (see the docstring of
:py:meth:`~sympy.solvers.ode.ode_separable`).
>>> pprint(dsolve(Eq(f(x).diff(x) + P(x)*f(x), Q(x)*f(x)), f(x),
... hint='separable_Integral'))
f(x)
/
| /
| 1 |
| - dy = C1 + | (-P(x) + Q(x)) dx
| y |
| /
/
Examples
========
>>> from sympy import Function, dsolve, Eq, pprint, log
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(Eq(x*f(x).diff(x) + f(x), log(x)*f(x)**2),
... f(x), hint='Bernoulli'))
1
f(x) = -------------------
/ log(x) 1\
x*|C1 + ------ + -|
\ x x/
References
==========
- https://en.wikipedia.org/wiki/Bernoulli_differential_equation
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 95
# indirect doctest
"""
x = func.args[0]
f = func.func
r = match # a*diff(f(x),x) + b*f(x) + c*f(x)**n, n != 1
C1 = get_numbered_constants(eq, num=1)
t = exp((1 - r[r['n']])*Integral(r[r['b']]/r[r['a']], x))
tt = (r[r['n']] - 1)*Integral(t*r[r['c']]/r[r['a']], x)
return Eq(f(x), ((tt + C1)/t)**(1/(1 - r[r['n']])))
def ode_Riccati_special_minus2(eq, func, order, match):
r"""
The general Riccati equation has the form
.. math:: dy/dx = f(x) y^2 + g(x) y + h(x)\text{.}
While it does not have a general solution [1], the "special" form, `dy/dx
= a y^2 - b x^c`, does have solutions in many cases [2]. This routine
returns a solution for `a(dy/dx) = b y^2 + c y/x + d/x^2` that is obtained
by using a suitable change of variables to reduce it to the special form
and is valid when neither `a` nor `b` are zero and either `c` or `d` is
zero.
>>> from sympy.abc import x, y, a, b, c, d
>>> from sympy.solvers.ode import dsolve, checkodesol
>>> from sympy import pprint, Function
>>> f = Function('f')
>>> y = f(x)
>>> genform = a*y.diff(x) - (b*y**2 + c*y/x + d/x**2)
>>> sol = dsolve(genform, y)
>>> pprint(sol, wrap_line=False)
/ / __________________ \\
| __________________ | / 2 ||
| / 2 | \/ 4*b*d - (a + c) *log(x)||
-|a + c - \/ 4*b*d - (a + c) *tan|C1 + ----------------------------||
\ \ 2*a //
f(x) = ------------------------------------------------------------------------
2*b*x
>>> checkodesol(genform, sol, order=1)[0]
True
References
==========
1. http://www.maplesoft.com/support/help/Maple/view.aspx?path=odeadvisor/Riccati
2. http://eqworld.ipmnet.ru/en/solutions/ode/ode0106.pdf -
http://eqworld.ipmnet.ru/en/solutions/ode/ode0123.pdf
"""
x = func.args[0]
f = func.func
r = match # a2*diff(f(x),x) + b2*f(x) + c2*f(x)/x + d2/x**2
a2, b2, c2, d2 = [r[r[s]] for s in 'a2 b2 c2 d2'.split()]
C1 = get_numbered_constants(eq, num=1)
mu = sqrt(4*d2*b2 - (a2 - c2)**2)
return Eq(f(x), (a2 - c2 - mu*tan(mu/(2*a2)*log(x) + C1))/(2*b2*x))
def ode_Liouville(eq, func, order, match):
r"""
Solves 2nd order Liouville differential equations.
The general form of a Liouville ODE is
.. math:: \frac{d^2 y}{dx^2} + g(y) \left(\!
\frac{dy}{dx}\!\right)^2 + h(x)
\frac{dy}{dx}\text{.}
The general solution is:
>>> from sympy import Function, dsolve, Eq, pprint, diff
>>> from sympy.abc import x
>>> f, g, h = map(Function, ['f', 'g', 'h'])
>>> genform = Eq(diff(f(x),x,x) + g(f(x))*diff(f(x),x)**2 +
... h(x)*diff(f(x),x), 0)
>>> pprint(genform)
2 2
/d \ d d
g(f(x))*|--(f(x))| + h(x)*--(f(x)) + ---(f(x)) = 0
\dx / dx 2
dx
>>> pprint(dsolve(genform, f(x), hint='Liouville_Integral'))
f(x)
/ /
| |
| / | /
| | | |
| - | h(x) dx | | g(y) dy
| | | |
| / | /
C1 + C2* | e dx + | e dy = 0
| |
/ /
Examples
========
>>> from sympy import Function, dsolve, Eq, pprint
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(diff(f(x), x, x) + diff(f(x), x)**2/f(x) +
... diff(f(x), x)/x, f(x), hint='Liouville'))
________________ ________________
[f(x) = -\/ C1 + C2*log(x) , f(x) = \/ C1 + C2*log(x) ]
References
==========
- Goldstein and Braun, "Advanced Methods for the Solution of Differential
Equations", pp. 98
- http://www.maplesoft.com/support/help/Maple/view.aspx?path=odeadvisor/Liouville
# indirect doctest
"""
# Liouville ODE:
# f(x).diff(x, 2) + g(f(x))*(f(x).diff(x, 2))**2 + h(x)*f(x).diff(x)
# See Goldstein and Braun, "Advanced Methods for the Solution of
# Differential Equations", pg. 98, as well as
# http://www.maplesoft.com/support/help/view.aspx?path=odeadvisor/Liouville
x = func.args[0]
f = func.func
r = match # f(x).diff(x, 2) + g*f(x).diff(x)**2 + h*f(x).diff(x)
y = r['y']
C1, C2 = get_numbered_constants(eq, num=2)
int = Integral(exp(Integral(r['g'], y)), (y, None, f(x)))
sol = Eq(int + C1*Integral(exp(-Integral(r['h'], x)), x) + C2, 0)
return sol
def ode_2nd_power_series_ordinary(eq, func, order, match):
r"""
Gives a power series solution to a second order homogeneous differential
equation with polynomial coefficients at an ordinary point. A homogenous
differential equation is of the form
.. math :: P(x)\frac{d^2y}{dx^2} + Q(x)\frac{dy}{dx} + R(x) = 0
For simplicity it is assumed that `P(x)`, `Q(x)` and `R(x)` are polynomials,
it is sufficient that `\frac{Q(x)}{P(x)}` and `\frac{R(x)}{P(x)}` exists at
`x_{0}`. A recurrence relation is obtained by substituting `y` as `\sum_{n=0}^\infty a_{n}x^{n}`,
in the differential equation, and equating the nth term. Using this relation
various terms can be generated.
Examples
========
>>> from sympy import dsolve, Function, pprint
>>> from sympy.abc import x, y
>>> f = Function("f")
>>> eq = f(x).diff(x, 2) + f(x)
>>> pprint(dsolve(eq, hint='2nd_power_series_ordinary'))
/ 4 2 \ / 2 \
|x x | | x | / 6\
f(x) = C2*|-- - -- + 1| + C1*x*|- -- + 1| + O\x /
\24 2 / \ 6 /
References
==========
- http://tutorial.math.lamar.edu/Classes/DE/SeriesSolutions.aspx
- George E. Simmons, "Differential Equations with Applications and
Historical Notes", p.p 176 - 184
"""
x = func.args[0]
f = func.func
C0, C1 = get_numbered_constants(eq, num=2)
n = Dummy("n", integer=True)
s = Wild("s")
k = Wild("k", exclude=[x])
x0 = match.get('x0')
terms = match.get('terms', 5)
p = match[match['a3']]
q = match[match['b3']]
r = match[match['c3']]
seriesdict = {}
recurr = Function("r")
# Generating the recurrence relation which works this way:
# for the second order term the summation begins at n = 2. The coefficients
# p is multiplied with an*(n - 1)*(n - 2)*x**n-2 and a substitution is made such that
# the exponent of x becomes n.
# For example, if p is x, then the second degree recurrence term is
# an*(n - 1)*(n - 2)*x**n-1, substituting (n - 1) as n, it transforms to
# an+1*n*(n - 1)*x**n.
# A similar process is done with the first order and zeroth order term.
coefflist = [(recurr(n), r), (n*recurr(n), q), (n*(n - 1)*recurr(n), p)]
for index, coeff in enumerate(coefflist):
if coeff[1]:
f2 = powsimp(expand((coeff[1]*(x - x0)**(n - index)).subs(x, x + x0)))
if f2.is_Add:
addargs = f2.args
else:
addargs = [f2]
for arg in addargs:
powm = arg.match(s*x**k)
term = coeff[0]*powm[s]
if not powm[k].is_Symbol:
term = term.subs(n, n - powm[k].as_independent(n)[0])
startind = powm[k].subs(n, index)
# Seeing if the startterm can be reduced further.
# If it vanishes for n lesser than startind, it is
# equal to summation from n.
if startind:
for i in reversed(range(startind)):
if not term.subs(n, i):
seriesdict[term] = i
else:
seriesdict[term] = i + 1
break
else:
seriesdict[term] = S(0)
# Stripping of terms so that the sum starts with the same number.
teq = S(0)
suminit = seriesdict.values()
rkeys = seriesdict.keys()
req = Add(*rkeys)
if any(suminit):
maxval = max(suminit)
for term in seriesdict:
val = seriesdict[term]
if val != maxval:
for i in range(val, maxval):
teq += term.subs(n, val)
finaldict = {}
if teq:
fargs = teq.atoms(AppliedUndef)
if len(fargs) == 1:
finaldict[fargs.pop()] = 0
else:
maxf = max(fargs, key = lambda x: x.args[0])
sol = solve(teq, maxf)
if isinstance(sol, list):
sol = sol[0]
finaldict[maxf] = sol
# Finding the recurrence relation in terms of the largest term.
fargs = req.atoms(AppliedUndef)
maxf = max(fargs, key = lambda x: x.args[0])
minf = min(fargs, key = lambda x: x.args[0])
if minf.args[0].is_Symbol:
startiter = 0
else:
startiter = -minf.args[0].as_independent(n)[0]
lhs = maxf
rhs = solve(req, maxf)
if isinstance(rhs, list):
rhs = rhs[0]
# Checking how many values are already present
tcounter = len([t for t in finaldict.values() if t])
for _ in range(tcounter, terms - 3): # Assuming c0 and c1 to be arbitrary
check = rhs.subs(n, startiter)
nlhs = lhs.subs(n, startiter)
nrhs = check.subs(finaldict)
finaldict[nlhs] = nrhs
startiter += 1
# Post processing
series = C0 + C1*(x - x0)
for term in finaldict:
if finaldict[term]:
fact = term.args[0]
series += (finaldict[term].subs([(recurr(0), C0), (recurr(1), C1)])*(
x - x0)**fact)
series = collect(expand_mul(series), [C0, C1]) + Order(x**terms)
return Eq(f(x), series)
def ode_2nd_power_series_regular(eq, func, order, match):
r"""
Gives a power series solution to a second order homogeneous differential
equation with polynomial coefficients at a regular point. A second order
homogenous differential equation is of the form
.. math :: P(x)\frac{d^2y}{dx^2} + Q(x)\frac{dy}{dx} + R(x) = 0
A point is said to regular singular at `x0` if `x - x0\frac{Q(x)}{P(x)}`
and `(x - x0)^{2}\frac{R(x)}{P(x)}` are analytic at `x0`. For simplicity
`P(x)`, `Q(x)` and `R(x)` are assumed to be polynomials. The algorithm for
finding the power series solutions is:
1. Try expressing `(x - x0)P(x)` and `((x - x0)^{2})Q(x)` as power series
solutions about x0. Find `p0` and `q0` which are the constants of the
power series expansions.
2. Solve the indicial equation `f(m) = m(m - 1) + m*p0 + q0`, to obtain the
roots `m1` and `m2` of the indicial equation.
3. If `m1 - m2` is a non integer there exists two series solutions. If
`m1 = m2`, there exists only one solution. If `m1 - m2` is an integer,
then the existence of one solution is confirmed. The other solution may
or may not exist.
The power series solution is of the form `x^{m}\sum_{n=0}^\infty a_{n}x^{n}`. The
coefficients are determined by the following recurrence relation.
`a_{n} = -\frac{\sum_{k=0}^{n-1} q_{n-k} + (m + k)p_{n-k}}{f(m + n)}`. For the case
in which `m1 - m2` is an integer, it can be seen from the recurrence relation
that for the lower root `m`, when `n` equals the difference of both the
roots, the denominator becomes zero. So if the numerator is not equal to zero,
a second series solution exists.
Examples
========
>>> from sympy import dsolve, Function, pprint
>>> from sympy.abc import x, y
>>> f = Function("f")
>>> eq = x*(f(x).diff(x, 2)) + 2*(f(x).diff(x)) + x*f(x)
>>> pprint(dsolve(eq))
/ 6 4 2 \
| x x x |
/ 4 2 \ C1*|- --- + -- - -- + 1|
| x x | \ 720 24 2 / / 6\
f(x) = C2*|--- - -- + 1| + ------------------------ + O\x /
\120 6 / x
References
==========
- George E. Simmons, "Differential Equations with Applications and
Historical Notes", p.p 176 - 184
"""
x = func.args[0]
f = func.func
C0, C1 = get_numbered_constants(eq, num=2)
n = Dummy("n")
m = Dummy("m") # for solving the indicial equation
s = Wild("s")
k = Wild("k", exclude=[x])
x0 = match.get('x0')
terms = match.get('terms', 5)
p = match['p']
q = match['q']
# Generating the indicial equation
indicial = []
for term in [p, q]:
if not term.has(x):
indicial.append(term)
else:
term = series(term, n=1, x0=x0)
if isinstance(term, Order):
indicial.append(S(0))
else:
for arg in term.args:
if not arg.has(x):
indicial.append(arg)
break
p0, q0 = indicial
sollist = solve(m*(m - 1) + m*p0 + q0, m)
if sollist and isinstance(sollist, list) and all(
[sol.is_real for sol in sollist]):
serdict1 = {}
serdict2 = {}
if len(sollist) == 1:
# Only one series solution exists in this case.
m1 = m2 = sollist.pop()
if terms-m1-1 <= 0:
return Eq(f(x), Order(terms))
serdict1 = _frobenius(terms-m1-1, m1, p0, q0, p, q, x0, x, C0)
else:
m1 = sollist[0]
m2 = sollist[1]
if m1 < m2:
m1, m2 = m2, m1
# Irrespective of whether m1 - m2 is an integer or not, one
# Frobenius series solution exists.
serdict1 = _frobenius(terms-m1-1, m1, p0, q0, p, q, x0, x, C0)
if not (m1 - m2).is_integer:
# Second frobenius series solution exists.
serdict2 = _frobenius(terms-m2-1, m2, p0, q0, p, q, x0, x, C1)
else:
# Check if second frobenius series solution exists.
serdict2 = _frobenius(terms-m2-1, m2, p0, q0, p, q, x0, x, C1, check=m1)
if serdict1:
finalseries1 = C0
for key in serdict1:
power = int(key.name[1:])
finalseries1 += serdict1[key]*(x - x0)**power
finalseries1 = (x - x0)**m1*finalseries1
finalseries2 = S(0)
if serdict2:
for key in serdict2:
power = int(key.name[1:])
finalseries2 += serdict2[key]*(x - x0)**power
finalseries2 += C1
finalseries2 = (x - x0)**m2*finalseries2
return Eq(f(x), collect(finalseries1 + finalseries2,
[C0, C1]) + Order(x**terms))
def _frobenius(n, m, p0, q0, p, q, x0, x, c, check=None):
r"""
Returns a dict with keys as coefficients and values as their values in terms of C0
"""
n = int(n)
# In cases where m1 - m2 is not an integer
m2 = check
d = Dummy("d")
numsyms = numbered_symbols("C", start=0)
numsyms = [next(numsyms) for i in range(n + 1)]
C0 = Symbol("C0")
serlist = []
for ser in [p, q]:
# Order term not present
if ser.is_polynomial(x) and Poly(ser, x).degree() <= n:
if x0:
ser = ser.subs(x, x + x0)
dict_ = Poly(ser, x).as_dict()
# Order term present
else:
tseries = series(ser, x=x0, n=n+1)
# Removing order
dict_ = Poly(list(ordered(tseries.args))[: -1], x).as_dict()
# Fill in with zeros, if coefficients are zero.
for i in range(n + 1):
if (i,) not in dict_:
dict_[(i,)] = S(0)
serlist.append(dict_)
pseries = serlist[0]
qseries = serlist[1]
indicial = d*(d - 1) + d*p0 + q0
frobdict = {}
for i in range(1, n + 1):
num = c*(m*pseries[(i,)] + qseries[(i,)])
for j in range(1, i):
sym = Symbol("C" + str(j))
num += frobdict[sym]*((m + j)*pseries[(i - j,)] + qseries[(i - j,)])
# Checking for cases when m1 - m2 is an integer. If num equals zero
# then a second Frobenius series solution cannot be found. If num is not zero
# then set constant as zero and proceed.
if m2 is not None and i == m2 - m:
if num:
return False
else:
frobdict[numsyms[i]] = S(0)
else:
frobdict[numsyms[i]] = -num/(indicial.subs(d, m+i))
return frobdict
def _nth_algebraic_match(eq, func):
r"""
Matches any differential equation that nth_algebraic can solve. Uses
`sympy.solve` but teaches it how to integrate derivatives.
This involves calling `sympy.solve` and does most of the work of finding a
solution (apart from evaluating the integrals).
"""
# Each integration should generate a different constant
constants = iter(numbered_symbols(prefix='C', cls=Symbol, start=1))
constant = lambda: next(constants, None)
# Like Derivative but "invertible"
class diffx(Function):
def inverse(self):
# We mustn't use integrate here because fx has been replaced by _t
# in the equation so integrals will not be correct while solve is
# still working.
return lambda expr: Integral(expr, var) + constant()
# Replace derivatives wrt the independent variable with diffx
def replace(eq, var):
def expand_diffx(*args):
differand, diffs = args[0], args[1:]
toreplace = differand
for v, n in diffs:
for _ in range(n):
if v == var:
toreplace = diffx(toreplace)
else:
toreplace = Derivative(toreplace, v)
return toreplace
return eq.replace(Derivative, expand_diffx)
# Restore derivatives in solution afterwards
def unreplace(eq, var):
return eq.replace(diffx, lambda e: Derivative(e, var))
# The independent variable
var = func.args[0]
subs_eqn = replace(eq, var)
try:
solns = solve(subs_eqn, func)
except NotImplementedError:
solns = []
solns = [unreplace(soln, var) for soln in solns]
solns = [Equality(func, soln) for soln in solns]
return {'var':var, 'solutions':solns}
def ode_nth_algebraic(eq, func, order, match):
r"""
Solves an `n`\th order ordinary differential equation using algebra and
integrals.
There is no general form for the kind of equation that this can solve. The
the equation is solved algebraically treating differentiation as an
invertible algebraic function.
Examples
========
>>> from sympy import Function, dsolve, Eq
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = Eq(f(x) * (f(x).diff(x)**2 - 1), 0)
>>> dsolve(eq, f(x), hint='nth_algebraic')
... # doctest: +NORMALIZE_WHITESPACE
[Eq(f(x), 0), Eq(f(x), C1 - x), Eq(f(x), C1 + x)]
Note that this solver can return algebraic solutions that do not have any
integration constants (f(x) = 0 in the above example).
# indirect doctest
"""
solns = match['solutions']
var = match['var']
solns = _nth_algebraic_remove_redundant_solutions(eq, solns, order, var)
if len(solns) == 1:
return solns[0]
else:
return solns
# FIXME: Maybe something like this function should be applied to the solutions
# returned by dsolve in general rather than just for nth_algebraic...
def _nth_algebraic_remove_redundant_solutions(eq, solns, order, var):
r"""
Remove redundant solutions from the set of solutions returned by
nth_algebraic.
This function is needed because otherwise nth_algebraic can return
redundant solutions where both algebraic solutions and integral
solutions are found to the ODE. As an example consider:
eq = Eq(f(x) * f(x).diff(x), 0)
There are two ways to find solutions to eq. The first is the algebraic
solution f(x)=0. The second is to solve the equation f(x).diff(x) = 0
leading to the solution f(x) = C1. In this particular case we then see
that the first solution is a special case of the second and we don't
want to return it.
This does not always happen for algebraic solutions though since if we
have
eq = Eq(f(x)*(1 + f(x).diff(x)), 0)
then we get the algebraic solution f(x) = 0 and the integral solution
f(x) = -x + C1 and in this case the two solutions are not equivalent wrt
initial conditions so both should be returned.
"""
def is_special_case_of(soln1, soln2):
return _nth_algebraic_is_special_case_of(soln1, soln2, eq, order, var)
unique_solns = []
for soln1 in solns:
for soln2 in unique_solns[:]:
if is_special_case_of(soln1, soln2):
break
elif is_special_case_of(soln2, soln1):
unique_solns.remove(soln2)
else:
unique_solns.append(soln1)
return unique_solns
def _nth_algebraic_is_special_case_of(soln1, soln2, eq, order, var):
r"""
True if soln1 is found to be a special case of soln2 wrt some value of the
constants that appear in soln2. False otherwise.
"""
# The solutions returned by nth_algebraic should be given explicitly as in
# Eq(f(x), expr). We will equate the RHSs of the two solutions giving an
# equation f1(x) = f2(x).
#
# Since this is supposed to hold for all x it also holds for derivatives
# f1'(x) and f2'(x). For an order n ode we should be able to differentiate
# each solution n times to get n+1 equations.
#
# We then try to solve those n+1 equations for the integrations constants
# in f2(x). If we can find a solution that doesn't depend on x then it
# means that some value of the constants in f1(x) is a special case of
# f2(x) corresponding to a paritcular choice of the integration constants.
constants1 = soln1.free_symbols.difference(eq.free_symbols)
constants2 = soln2.free_symbols.difference(eq.free_symbols)
constants1_new = get_numbered_constants(soln1.rhs - soln2.rhs, len(constants1))
if len(constants1) == 1:
constants1_new = {constants1_new}
for c_old, c_new in zip(constants1, constants1_new):
soln1 = soln1.subs(c_old, c_new)
# n equations for f1(x)=f2(x), f1'(x)=f2'(x), ...
lhs = soln1.rhs.doit()
rhs = soln2.rhs.doit()
eqns = [Eq(lhs, rhs)]
for n in range(1, order):
lhs = lhs.diff(var)
rhs = rhs.diff(var)
eq = Eq(lhs, rhs)
eqns.append(eq)
# BooleanTrue/False awkwardly show up for trivial equations
if any(isinstance(eq, BooleanFalse) for eq in eqns):
return False
eqns = [eq for eq in eqns if not isinstance(eq, BooleanTrue)]
constant_solns = solve(eqns, constants2)
# Sometimes returns a dict and sometimes a list of dicts
if isinstance(constant_solns, dict):
constant_solns = [constant_solns]
# If any solution gives all constants as expressions that don't depend on
# x then there exists constants for soln2 that give soln1
for constant_soln in constant_solns:
if not any(c.has(var) for c in constant_soln.values()):
return True
else:
return False
def _nth_linear_match(eq, func, order):
r"""
Matches a differential equation to the linear form:
.. math:: a_n(x) y^{(n)} + \cdots + a_1(x)y' + a_0(x) y + B(x) = 0
Returns a dict of order:coeff terms, where order is the order of the
derivative on each term, and coeff is the coefficient of that derivative.
The key ``-1`` holds the function `B(x)`. Returns ``None`` if the ODE is
not linear. This function assumes that ``func`` has already been checked
to be good.
Examples
========
>>> from sympy import Function, cos, sin
>>> from sympy.abc import x
>>> from sympy.solvers.ode import _nth_linear_match
>>> f = Function('f')
>>> _nth_linear_match(f(x).diff(x, 3) + 2*f(x).diff(x) +
... x*f(x).diff(x, 2) + cos(x)*f(x).diff(x) + x - f(x) -
... sin(x), f(x), 3)
{-1: x - sin(x), 0: -1, 1: cos(x) + 2, 2: x, 3: 1}
>>> _nth_linear_match(f(x).diff(x, 3) + 2*f(x).diff(x) +
... x*f(x).diff(x, 2) + cos(x)*f(x).diff(x) + x - f(x) -
... sin(f(x)), f(x), 3) == None
True
"""
x = func.args[0]
one_x = {x}
terms = {i: S.Zero for i in range(-1, order + 1)}
for i in Add.make_args(eq):
if not i.has(func):
terms[-1] += i
else:
c, f = i.as_independent(func)
if (isinstance(f, Derivative)
and set(f.variables) == one_x
and f.args[0] == func):
terms[f.derivative_count] += c
elif f == func:
terms[len(f.args[1:])] += c
else:
return None
return terms
def ode_nth_linear_euler_eq_homogeneous(eq, func, order, match, returns='sol'):
r"""
Solves an `n`\th order linear homogeneous variable-coefficient
Cauchy-Euler equidimensional ordinary differential equation.
This is an equation with form `0 = a_0 f(x) + a_1 x f'(x) + a_2 x^2 f''(x)
\cdots`.
These equations can be solved in a general manner, by substituting
solutions of the form `f(x) = x^r`, and deriving a characteristic equation
for `r`. When there are repeated roots, we include extra terms of the
form `C_{r k} \ln^k(x) x^r`, where `C_{r k}` is an arbitrary integration
constant, `r` is a root of the characteristic equation, and `k` ranges
over the multiplicity of `r`. In the cases where the roots are complex,
solutions of the form `C_1 x^a \sin(b \log(x)) + C_2 x^a \cos(b \log(x))`
are returned, based on expansions with Euler's formula. The general
solution is the sum of the terms found. If SymPy cannot find exact roots
to the characteristic equation, a
:py:class:`~sympy.polys.rootoftools.CRootOf` instance will be returned
instead.
>>> from sympy import Function, dsolve, Eq
>>> from sympy.abc import x
>>> f = Function('f')
>>> dsolve(4*x**2*f(x).diff(x, 2) + f(x), f(x),
... hint='nth_linear_euler_eq_homogeneous')
... # doctest: +NORMALIZE_WHITESPACE
Eq(f(x), sqrt(x)*(C1 + C2*log(x)))
Note that because this method does not involve integration, there is no
``nth_linear_euler_eq_homogeneous_Integral`` hint.
The following is for internal use:
- ``returns = 'sol'`` returns the solution to the ODE.
- ``returns = 'list'`` returns a list of linearly independent solutions,
corresponding to the fundamental solution set, for use with non
homogeneous solution methods like variation of parameters and
undetermined coefficients. Note that, though the solutions should be
linearly independent, this function does not explicitly check that. You
can do ``assert simplify(wronskian(sollist)) != 0`` to check for linear
independence. Also, ``assert len(sollist) == order`` will need to pass.
- ``returns = 'both'``, return a dictionary ``{'sol': <solution to ODE>,
'list': <list of linearly independent solutions>}``.
Examples
========
>>> from sympy import Function, dsolve, pprint
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = f(x).diff(x, 2)*x**2 - 4*f(x).diff(x)*x + 6*f(x)
>>> pprint(dsolve(eq, f(x),
... hint='nth_linear_euler_eq_homogeneous'))
2
f(x) = x *(C1 + C2*x)
References
==========
- https://en.wikipedia.org/wiki/Cauchy%E2%80%93Euler_equation
- C. Bender & S. Orszag, "Advanced Mathematical Methods for Scientists and
Engineers", Springer 1999, pp. 12
# indirect doctest
"""
global collectterms
collectterms = []
x = func.args[0]
f = func.func
r = match
# First, set up characteristic equation.
chareq, symbol = S.Zero, Dummy('x')
for i in r.keys():
if not isinstance(i, str) and i >= 0:
chareq += (r[i]*diff(x**symbol, x, i)*x**-symbol).expand()
chareq = Poly(chareq, symbol)
chareqroots = [rootof(chareq, k) for k in range(chareq.degree())]
# A generator of constants
constants = list(get_numbered_constants(eq, num=chareq.degree()*2))
constants.reverse()
# Create a dict root: multiplicity or charroots
charroots = defaultdict(int)
for root in chareqroots:
charroots[root] += 1
gsol = S(0)
# We need keep track of terms so we can run collect() at the end.
# This is necessary for constantsimp to work properly.
ln = log
for root, multiplicity in charroots.items():
for i in range(multiplicity):
if isinstance(root, RootOf):
gsol += (x**root) * constants.pop()
if multiplicity != 1:
raise ValueError("Value should be 1")
collectterms = [(0, root, 0)] + collectterms
elif root.is_real:
gsol += ln(x)**i*(x**root) * constants.pop()
collectterms = [(i, root, 0)] + collectterms
else:
reroot = re(root)
imroot = im(root)
gsol += ln(x)**i * (x**reroot) * (
constants.pop() * sin(abs(imroot)*ln(x))
+ constants.pop() * cos(imroot*ln(x)))
# Preserve ordering (multiplicity, real part, imaginary part)
# It will be assumed implicitly when constructing
# fundamental solution sets.
collectterms = [(i, reroot, imroot)] + collectterms
if returns == 'sol':
return Eq(f(x), gsol)
elif returns in ('list' 'both'):
# HOW TO TEST THIS CODE? (dsolve does not pass 'returns' through)
# Create a list of (hopefully) linearly independent solutions
gensols = []
# Keep track of when to use sin or cos for nonzero imroot
for i, reroot, imroot in collectterms:
if imroot == 0:
gensols.append(ln(x)**i*x**reroot)
else:
sin_form = ln(x)**i*x**reroot*sin(abs(imroot)*ln(x))
if sin_form in gensols:
cos_form = ln(x)**i*x**reroot*cos(imroot*ln(x))
gensols.append(cos_form)
else:
gensols.append(sin_form)
if returns == 'list':
return gensols
else:
return {'sol': Eq(f(x), gsol), 'list': gensols}
else:
raise ValueError('Unknown value for key "returns".')
def ode_nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients(eq, func, order, match, returns='sol'):
r"""
Solves an `n`\th order linear non homogeneous Cauchy-Euler equidimensional
ordinary differential equation using undetermined coefficients.
This is an equation with form `g(x) = a_0 f(x) + a_1 x f'(x) + a_2 x^2 f''(x)
\cdots`.
These equations can be solved in a general manner, by substituting
solutions of the form `x = exp(t)`, and deriving a characteristic equation
of form `g(exp(t)) = b_0 f(t) + b_1 f'(t) + b_2 f''(t) \cdots` which can
be then solved by nth_linear_constant_coeff_undetermined_coefficients if
g(exp(t)) has finite number of linearly independent derivatives.
Functions that fit this requirement are finite sums functions of the form
`a x^i e^{b x} \sin(c x + d)` or `a x^i e^{b x} \cos(c x + d)`, where `i`
is a non-negative integer and `a`, `b`, `c`, and `d` are constants. For
example any polynomial in `x`, functions like `x^2 e^{2 x}`, `x \sin(x)`,
and `e^x \cos(x)` can all be used. Products of `\sin`'s and `\cos`'s have
a finite number of derivatives, because they can be expanded into `\sin(a
x)` and `\cos(b x)` terms. However, SymPy currently cannot do that
expansion, so you will need to manually rewrite the expression in terms of
the above to use this method. So, for example, you will need to manually
convert `\sin^2(x)` into `(1 + \cos(2 x))/2` to properly apply the method
of undetermined coefficients on it.
After replacement of x by exp(t), this method works by creating a trial function
from the expression and all of its linear independent derivatives and
substituting them into the original ODE. The coefficients for each term
will be a system of linear equations, which are be solved for and
substituted, giving the solution. If any of the trial functions are linearly
dependent on the solution to the homogeneous equation, they are multiplied
by sufficient `x` to make them linearly independent.
Examples
========
>>> from sympy import dsolve, Function, Derivative, log
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = x**2*Derivative(f(x), x, x) - 2*x*Derivative(f(x), x) + 2*f(x) - log(x)
>>> dsolve(eq, f(x),
... hint='nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients').expand()
Eq(f(x), C1*x + C2*x**2 + log(x)/2 + 3/4)
"""
x = func.args[0]
f = func.func
r = match
chareq, eq, symbol = S.Zero, S.Zero, Dummy('x')
for i in r.keys():
if not isinstance(i, str) and i >= 0:
chareq += (r[i]*diff(x**symbol, x, i)*x**-symbol).expand()
for i in range(1,degree(Poly(chareq, symbol))+1):
eq += chareq.coeff(symbol**i)*diff(f(x), x, i)
if chareq.as_coeff_add(symbol)[0]:
eq += chareq.as_coeff_add(symbol)[0]*f(x)
e, re = posify(r[-1].subs(x, exp(x)))
eq += e.subs(re)
match = _nth_linear_match(eq, f(x), ode_order(eq, f(x)))
match['trialset'] = r['trialset']
return ode_nth_linear_constant_coeff_undetermined_coefficients(eq, func, order, match).subs(x, log(x)).subs(f(log(x)), f(x)).expand()
def ode_nth_linear_euler_eq_nonhomogeneous_variation_of_parameters(eq, func, order, match, returns='sol'):
r"""
Solves an `n`\th order linear non homogeneous Cauchy-Euler equidimensional
ordinary differential equation using variation of parameters.
This is an equation with form `g(x) = a_0 f(x) + a_1 x f'(x) + a_2 x^2 f''(x)
\cdots`.
This method works by assuming that the particular solution takes the form
.. math:: \sum_{x=1}^{n} c_i(x) y_i(x) {a_n} {x^n} \text{,}
where `y_i` is the `i`\th solution to the homogeneous equation. The
solution is then solved using Wronskian's and Cramer's Rule. The
particular solution is given by multiplying eq given below with `a_n x^{n}`
.. math:: \sum_{x=1}^n \left( \int \frac{W_i(x)}{W(x)} \,dx
\right) y_i(x) \text{,}
where `W(x)` is the Wronskian of the fundamental system (the system of `n`
linearly independent solutions to the homogeneous equation), and `W_i(x)`
is the Wronskian of the fundamental system with the `i`\th column replaced
with `[0, 0, \cdots, 0, \frac{x^{- n}}{a_n} g{\left (x \right )}]`.
This method is general enough to solve any `n`\th order inhomogeneous
linear differential equation, but sometimes SymPy cannot simplify the
Wronskian well enough to integrate it. If this method hangs, try using the
``nth_linear_constant_coeff_variation_of_parameters_Integral`` hint and
simplifying the integrals manually. Also, prefer using
``nth_linear_constant_coeff_undetermined_coefficients`` when it
applies, because it doesn't use integration, making it faster and more
reliable.
Warning, using simplify=False with
'nth_linear_constant_coeff_variation_of_parameters' in
:py:meth:`~sympy.solvers.ode.dsolve` may cause it to hang, because it will
not attempt to simplify the Wronskian before integrating. It is
recommended that you only use simplify=False with
'nth_linear_constant_coeff_variation_of_parameters_Integral' for this
method, especially if the solution to the homogeneous equation has
trigonometric functions in it.
Examples
========
>>> from sympy import Function, dsolve, Derivative
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = x**2*Derivative(f(x), x, x) - 2*x*Derivative(f(x), x) + 2*f(x) - x**4
>>> dsolve(eq, f(x),
... hint='nth_linear_euler_eq_nonhomogeneous_variation_of_parameters').expand()
Eq(f(x), C1*x + C2*x**2 + x**4/6)
"""
x = func.args[0]
f = func.func
r = match
gensol = ode_nth_linear_euler_eq_homogeneous(eq, func, order, match, returns='both')
match.update(gensol)
r[-1] = r[-1]/r[ode_order(eq, f(x))]
sol = _solve_variation_of_parameters(eq, func, order, match)
return Eq(f(x), r['sol'].rhs + (sol.rhs - r['sol'].rhs)*r[ode_order(eq, f(x))])
def ode_almost_linear(eq, func, order, match):
r"""
Solves an almost-linear differential equation.
The general form of an almost linear differential equation is
.. math:: f(x) g(y) y + k(x) l(y) + m(x) = 0
\text{where} l'(y) = g(y)\text{.}
This can be solved by substituting `l(y) = u(y)`. Making the given
substitution reduces it to a linear differential equation of the form `u'
+ P(x) u + Q(x) = 0`.
The general solution is
>>> from sympy import Function, dsolve, Eq, pprint
>>> from sympy.abc import x, y, n
>>> f, g, k, l = map(Function, ['f', 'g', 'k', 'l'])
>>> genform = Eq(f(x)*(l(y).diff(y)) + k(x)*l(y) + g(x))
>>> pprint(genform)
d
f(x)*--(l(y)) + g(x) + k(x)*l(y) = 0
dy
>>> pprint(dsolve(genform, hint = 'almost_linear'))
/ // y*k(x) \\
| || ------ ||
| || f(x) || -y*k(x)
| ||-g(x)*e || --------
| ||-------------- for k(x) != 0|| f(x)
l(y) = |C1 + |< k(x) ||*e
| || ||
| || -y*g(x) ||
| || -------- otherwise ||
| || f(x) ||
\ \\ //
See Also
========
:meth:`sympy.solvers.ode.ode_1st_linear`
Examples
========
>>> from sympy import Function, Derivative, pprint
>>> from sympy.solvers.ode import dsolve, classify_ode
>>> from sympy.abc import x
>>> f = Function('f')
>>> d = f(x).diff(x)
>>> eq = x*d + x*f(x) + 1
>>> dsolve(eq, f(x), hint='almost_linear')
Eq(f(x), (C1 - Ei(x))*exp(-x))
>>> pprint(dsolve(eq, f(x), hint='almost_linear'))
-x
f(x) = (C1 - Ei(x))*e
References
==========
- Joel Moses, "Symbolic Integration - The Stormy Decade", Communications
of the ACM, Volume 14, Number 8, August 1971, pp. 558
"""
# Since ode_1st_linear has already been implemented, and the
# coefficients have been modified to the required form in
# classify_ode, just passing eq, func, order and match to
# ode_1st_linear will give the required output.
return ode_1st_linear(eq, func, order, match)
def _linear_coeff_match(expr, func):
r"""
Helper function to match hint ``linear_coefficients``.
Matches the expression to the form `(a_1 x + b_1 f(x) + c_1)/(a_2 x + b_2
f(x) + c_2)` where the following conditions hold:
1. `a_1`, `b_1`, `c_1`, `a_2`, `b_2`, `c_2` are Rationals;
2. `c_1` or `c_2` are not equal to zero;
3. `a_2 b_1 - a_1 b_2` is not equal to zero.
Return ``xarg``, ``yarg`` where
1. ``xarg`` = `(b_2 c_1 - b_1 c_2)/(a_2 b_1 - a_1 b_2)`
2. ``yarg`` = `(a_1 c_2 - a_2 c_1)/(a_2 b_1 - a_1 b_2)`
Examples
========
>>> from sympy import Function
>>> from sympy.abc import x
>>> from sympy.solvers.ode import _linear_coeff_match
>>> from sympy.functions.elementary.trigonometric import sin
>>> f = Function('f')
>>> _linear_coeff_match((
... (-25*f(x) - 8*x + 62)/(4*f(x) + 11*x - 11)), f(x))
(1/9, 22/9)
>>> _linear_coeff_match(
... sin((-5*f(x) - 8*x + 6)/(4*f(x) + x - 1)), f(x))
(19/27, 2/27)
>>> _linear_coeff_match(sin(f(x)/x), f(x))
"""
f = func.func
x = func.args[0]
def abc(eq):
r'''
Internal function of _linear_coeff_match
that returns Rationals a, b, c
if eq is a*x + b*f(x) + c, else None.
'''
eq = _mexpand(eq)
c = eq.as_independent(x, f(x), as_Add=True)[0]
if not c.is_Rational:
return
a = eq.coeff(x)
if not a.is_Rational:
return
b = eq.coeff(f(x))
if not b.is_Rational:
return
if eq == a*x + b*f(x) + c:
return a, b, c
def match(arg):
r'''
Internal function of _linear_coeff_match that returns Rationals a1,
b1, c1, a2, b2, c2 and a2*b1 - a1*b2 of the expression (a1*x + b1*f(x)
+ c1)/(a2*x + b2*f(x) + c2) if one of c1 or c2 and a2*b1 - a1*b2 is
non-zero, else None.
'''
n, d = arg.together().as_numer_denom()
m = abc(n)
if m is not None:
a1, b1, c1 = m
m = abc(d)
if m is not None:
a2, b2, c2 = m
d = a2*b1 - a1*b2
if (c1 or c2) and d:
return a1, b1, c1, a2, b2, c2, d
m = [fi.args[0] for fi in expr.atoms(Function) if fi.func != f and
len(fi.args) == 1 and not fi.args[0].is_Function] or {expr}
m1 = match(m.pop())
if m1 and all(match(mi) == m1 for mi in m):
a1, b1, c1, a2, b2, c2, denom = m1
return (b2*c1 - b1*c2)/denom, (a1*c2 - a2*c1)/denom
def ode_linear_coefficients(eq, func, order, match):
r"""
Solves a differential equation with linear coefficients.
The general form of a differential equation with linear coefficients is
.. math:: y' + F\left(\!\frac{a_1 x + b_1 y + c_1}{a_2 x + b_2 y +
c_2}\!\right) = 0\text{,}
where `a_1`, `b_1`, `c_1`, `a_2`, `b_2`, `c_2` are constants and `a_1 b_2
- a_2 b_1 \ne 0`.
This can be solved by substituting:
.. math:: x = x' + \frac{b_2 c_1 - b_1 c_2}{a_2 b_1 - a_1 b_2}
y = y' + \frac{a_1 c_2 - a_2 c_1}{a_2 b_1 - a_1
b_2}\text{.}
This substitution reduces the equation to a homogeneous differential
equation.
See Also
========
:meth:`sympy.solvers.ode.ode_1st_homogeneous_coeff_best`
:meth:`sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_indep_div_dep`
:meth:`sympy.solvers.ode.ode_1st_homogeneous_coeff_subs_dep_div_indep`
Examples
========
>>> from sympy import Function, Derivative, pprint
>>> from sympy.solvers.ode import dsolve, classify_ode
>>> from sympy.abc import x
>>> f = Function('f')
>>> df = f(x).diff(x)
>>> eq = (x + f(x) + 1)*df + (f(x) - 6*x + 1)
>>> dsolve(eq, hint='linear_coefficients')
[Eq(f(x), -x - sqrt(C1 + 7*x**2) - 1), Eq(f(x), -x + sqrt(C1 + 7*x**2) - 1)]
>>> pprint(dsolve(eq, hint='linear_coefficients'))
___________ ___________
/ 2 / 2
[f(x) = -x - \/ C1 + 7*x - 1, f(x) = -x + \/ C1 + 7*x - 1]
References
==========
- Joel Moses, "Symbolic Integration - The Stormy Decade", Communications
of the ACM, Volume 14, Number 8, August 1971, pp. 558
"""
return ode_1st_homogeneous_coeff_best(eq, func, order, match)
def ode_separable_reduced(eq, func, order, match):
r"""
Solves a differential equation that can be reduced to the separable form.
The general form of this equation is
.. math:: y' + (y/x) H(x^n y) = 0\text{}.
This can be solved by substituting `u(y) = x^n y`. The equation then
reduces to the separable form `\frac{u'}{u (\mathrm{power} - H(u))} -
\frac{1}{x} = 0`.
The general solution is:
>>> from sympy import Function, dsolve, Eq, pprint
>>> from sympy.abc import x, n
>>> f, g = map(Function, ['f', 'g'])
>>> genform = f(x).diff(x) + (f(x)/x)*g(x**n*f(x))
>>> pprint(genform)
/ n \
d f(x)*g\x *f(x)/
--(f(x)) + ---------------
dx x
>>> pprint(dsolve(genform, hint='separable_reduced'))
n
x *f(x)
/
|
| 1
| ------------ dy = C1 + log(x)
| y*(n - g(y))
|
/
See Also
========
:meth:`sympy.solvers.ode.ode_separable`
Examples
========
>>> from sympy import Function, Derivative, pprint
>>> from sympy.solvers.ode import dsolve, classify_ode
>>> from sympy.abc import x
>>> f = Function('f')
>>> d = f(x).diff(x)
>>> eq = (x - x**2*f(x))*d - f(x)
>>> dsolve(eq, hint='separable_reduced')
[Eq(f(x), (-sqrt(C1*x**2 + 1) + 1)/x), Eq(f(x), (sqrt(C1*x**2 + 1) + 1)/x)]
>>> pprint(dsolve(eq, hint='separable_reduced'))
___________ ___________
/ 2 / 2
- \/ C1*x + 1 + 1 \/ C1*x + 1 + 1
[f(x) = --------------------, f(x) = ------------------]
x x
References
==========
- Joel Moses, "Symbolic Integration - The Stormy Decade", Communications
of the ACM, Volume 14, Number 8, August 1971, pp. 558
"""
# Arguments are passed in a way so that they are coherent with the
# ode_separable function
x = func.args[0]
f = func.func
y = Dummy('y')
u = match['u'].subs(match['t'], y)
ycoeff = 1/(y*(match['power'] - u))
m1 = {y: 1, x: -1/x, 'coeff': 1}
m2 = {y: ycoeff, x: 1, 'coeff': 1}
r = {'m1': m1, 'm2': m2, 'y': y, 'hint': x**match['power']*f(x)}
return ode_separable(eq, func, order, r)
def ode_1st_power_series(eq, func, order, match):
r"""
The power series solution is a method which gives the Taylor series expansion
to the solution of a differential equation.
For a first order differential equation `\frac{dy}{dx} = h(x, y)`, a power
series solution exists at a point `x = x_{0}` if `h(x, y)` is analytic at `x_{0}`.
The solution is given by
.. math:: y(x) = y(x_{0}) + \sum_{n = 1}^{\infty} \frac{F_{n}(x_{0},b)(x - x_{0})^n}{n!},
where `y(x_{0}) = b` is the value of y at the initial value of `x_{0}`.
To compute the values of the `F_{n}(x_{0},b)` the following algorithm is
followed, until the required number of terms are generated.
1. `F_1 = h(x_{0}, b)`
2. `F_{n+1} = \frac{\partial F_{n}}{\partial x} + \frac{\partial F_{n}}{\partial y}F_{1}`
Examples
========
>>> from sympy import Function, Derivative, pprint, exp
>>> from sympy.solvers.ode import dsolve
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = exp(x)*(f(x).diff(x)) - f(x)
>>> pprint(dsolve(eq, hint='1st_power_series'))
3 4 5
C1*x C1*x C1*x / 6\
f(x) = C1 + C1*x - ----- + ----- + ----- + O\x /
6 24 60
References
==========
- Travis W. Walker, Analytic power series technique for solving first-order
differential equations, p.p 17, 18
"""
x = func.args[0]
y = match['y']
f = func.func
h = -match[match['d']]/match[match['e']]
point = match.get('f0')
value = match.get('f0val')
terms = match.get('terms')
# First term
F = h
if not h:
return Eq(f(x), value)
# Initialization
series = value
if terms > 1:
hc = h.subs({x: point, y: value})
if hc.has(oo) or hc.has(NaN) or hc.has(zoo):
# Derivative does not exist, not analytic
return Eq(f(x), oo)
elif hc:
series += hc*(x - point)
for factcount in range(2, terms):
Fnew = F.diff(x) + F.diff(y)*h
Fnewc = Fnew.subs({x: point, y: value})
# Same logic as above
if Fnewc.has(oo) or Fnewc.has(NaN) or Fnewc.has(-oo) or Fnewc.has(zoo):
return Eq(f(x), oo)
series += Fnewc*((x - point)**factcount)/factorial(factcount)
F = Fnew
series += Order(x**terms)
return Eq(f(x), series)
def ode_nth_linear_constant_coeff_homogeneous(eq, func, order, match,
returns='sol'):
r"""
Solves an `n`\th order linear homogeneous differential equation with
constant coefficients.
This is an equation of the form
.. math:: a_n f^{(n)}(x) + a_{n-1} f^{(n-1)}(x) + \cdots + a_1 f'(x)
+ a_0 f(x) = 0\text{.}
These equations can be solved in a general manner, by taking the roots of
the characteristic equation `a_n m^n + a_{n-1} m^{n-1} + \cdots + a_1 m +
a_0 = 0`. The solution will then be the sum of `C_n x^i e^{r x}` terms,
for each where `C_n` is an arbitrary constant, `r` is a root of the
characteristic equation and `i` is one of each from 0 to the multiplicity
of the root - 1 (for example, a root 3 of multiplicity 2 would create the
terms `C_1 e^{3 x} + C_2 x e^{3 x}`). The exponential is usually expanded
for complex roots using Euler's equation `e^{I x} = \cos(x) + I \sin(x)`.
Complex roots always come in conjugate pairs in polynomials with real
coefficients, so the two roots will be represented (after simplifying the
constants) as `e^{a x} \left(C_1 \cos(b x) + C_2 \sin(b x)\right)`.
If SymPy cannot find exact roots to the characteristic equation, a
:py:class:`~sympy.polys.rootoftools.CRootOf` instance will be return
instead.
>>> from sympy import Function, dsolve, Eq
>>> from sympy.abc import x
>>> f = Function('f')
>>> dsolve(f(x).diff(x, 5) + 10*f(x).diff(x) - 2*f(x), f(x),
... hint='nth_linear_constant_coeff_homogeneous')
... # doctest: +NORMALIZE_WHITESPACE
Eq(f(x), C5*exp(x*CRootOf(_x**5 + 10*_x - 2, 0))
+ (C1*sin(x*im(CRootOf(_x**5 + 10*_x - 2, 1)))
+ C2*cos(x*im(CRootOf(_x**5 + 10*_x - 2, 1))))*exp(x*re(CRootOf(_x**5 + 10*_x - 2, 1)))
+ (C3*sin(x*im(CRootOf(_x**5 + 10*_x - 2, 3)))
+ C4*cos(x*im(CRootOf(_x**5 + 10*_x - 2, 3))))*exp(x*re(CRootOf(_x**5 + 10*_x - 2, 3))))
Note that because this method does not involve integration, there is no
``nth_linear_constant_coeff_homogeneous_Integral`` hint.
The following is for internal use:
- ``returns = 'sol'`` returns the solution to the ODE.
- ``returns = 'list'`` returns a list of linearly independent solutions,
for use with non homogeneous solution methods like variation of
parameters and undetermined coefficients. Note that, though the
solutions should be linearly independent, this function does not
explicitly check that. You can do ``assert simplify(wronskian(sollist))
!= 0`` to check for linear independence. Also, ``assert len(sollist) ==
order`` will need to pass.
- ``returns = 'both'``, return a dictionary ``{'sol': <solution to ODE>,
'list': <list of linearly independent solutions>}``.
Examples
========
>>> from sympy import Function, dsolve, pprint
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(f(x).diff(x, 4) + 2*f(x).diff(x, 3) -
... 2*f(x).diff(x, 2) - 6*f(x).diff(x) + 5*f(x), f(x),
... hint='nth_linear_constant_coeff_homogeneous'))
x -2*x
f(x) = (C1 + C2*x)*e + (C3*sin(x) + C4*cos(x))*e
References
==========
- https://en.wikipedia.org/wiki/Linear_differential_equation section:
Nonhomogeneous_equation_with_constant_coefficients
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 211
# indirect doctest
"""
x = func.args[0]
f = func.func
r = match
# First, set up characteristic equation.
chareq, symbol = S.Zero, Dummy('x')
for i in r.keys():
if type(i) == str or i < 0:
pass
else:
chareq += r[i]*symbol**i
chareq = Poly(chareq, symbol)
# Can't just call roots because it doesn't return rootof for unsolveable
# polynomials.
chareqroots = roots(chareq, multiple=True)
if len(chareqroots) != order:
chareqroots = [rootof(chareq, k) for k in range(chareq.degree())]
chareq_is_complex = not all([i.is_real for i in chareq.all_coeffs()])
# A generator of constants
constants = list(get_numbered_constants(eq, num=chareq.degree()*2))
# Create a dict root: multiplicity or charroots
charroots = defaultdict(int)
for root in chareqroots:
charroots[root] += 1
gsol = S(0)
# We need to keep track of terms so we can run collect() at the end.
# This is necessary for constantsimp to work properly.
global collectterms
collectterms = []
gensols = []
conjugate_roots = [] # used to prevent double-use of conjugate roots
# Loop over roots in theorder provided by roots/rootof...
for root in chareqroots:
# but don't repoeat multiple roots.
if root not in charroots:
continue
multiplicity = charroots.pop(root)
for i in range(multiplicity):
if chareq_is_complex:
gensols.append(x**i*exp(root*x))
collectterms = [(i, root, 0)] + collectterms
continue
reroot = re(root)
imroot = im(root)
if imroot.has(atan2) and reroot.has(atan2):
# Remove this condition when re and im stop returning
# circular atan2 usages.
gensols.append(x**i*exp(root*x))
collectterms = [(i, root, 0)] + collectterms
else:
if root in conjugate_roots:
collectterms = [(i, reroot, imroot)] + collectterms
continue
if imroot == 0:
gensols.append(x**i*exp(reroot*x))
collectterms = [(i, reroot, 0)] + collectterms
continue
conjugate_roots.append(conjugate(root))
gensols.append(x**i*exp(reroot*x) * sin(abs(imroot) * x))
gensols.append(x**i*exp(reroot*x) * cos( imroot * x))
# This ordering is important
collectterms = [(i, reroot, imroot)] + collectterms
if returns == 'list':
return gensols
elif returns in ('sol' 'both'):
gsol = Add(*[i*j for (i,j) in zip(constants, gensols)])
if returns == 'sol':
return Eq(f(x), gsol)
else:
return {'sol': Eq(f(x), gsol), 'list': gensols}
else:
raise ValueError('Unknown value for key "returns".')
def ode_nth_linear_constant_coeff_undetermined_coefficients(eq, func, order, match):
r"""
Solves an `n`\th order linear differential equation with constant
coefficients using the method of undetermined coefficients.
This method works on differential equations of the form
.. math:: a_n f^{(n)}(x) + a_{n-1} f^{(n-1)}(x) + \cdots + a_1 f'(x)
+ a_0 f(x) = P(x)\text{,}
where `P(x)` is a function that has a finite number of linearly
independent derivatives.
Functions that fit this requirement are finite sums functions of the form
`a x^i e^{b x} \sin(c x + d)` or `a x^i e^{b x} \cos(c x + d)`, where `i`
is a non-negative integer and `a`, `b`, `c`, and `d` are constants. For
example any polynomial in `x`, functions like `x^2 e^{2 x}`, `x \sin(x)`,
and `e^x \cos(x)` can all be used. Products of `\sin`'s and `\cos`'s have
a finite number of derivatives, because they can be expanded into `\sin(a
x)` and `\cos(b x)` terms. However, SymPy currently cannot do that
expansion, so you will need to manually rewrite the expression in terms of
the above to use this method. So, for example, you will need to manually
convert `\sin^2(x)` into `(1 + \cos(2 x))/2` to properly apply the method
of undetermined coefficients on it.
This method works by creating a trial function from the expression and all
of its linear independent derivatives and substituting them into the
original ODE. The coefficients for each term will be a system of linear
equations, which are be solved for and substituted, giving the solution.
If any of the trial functions are linearly dependent on the solution to
the homogeneous equation, they are multiplied by sufficient `x` to make
them linearly independent.
Examples
========
>>> from sympy import Function, dsolve, pprint, exp, cos
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(f(x).diff(x, 2) + 2*f(x).diff(x) + f(x) -
... 4*exp(-x)*x**2 + cos(2*x), f(x),
... hint='nth_linear_constant_coeff_undetermined_coefficients'))
/ 4\
| x | -x 4*sin(2*x) 3*cos(2*x)
f(x) = |C1 + C2*x + --|*e - ---------- + ----------
\ 3 / 25 25
References
==========
- https://en.wikipedia.org/wiki/Method_of_undetermined_coefficients
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 221
# indirect doctest
"""
gensol = ode_nth_linear_constant_coeff_homogeneous(eq, func, order, match,
returns='both')
match.update(gensol)
return _solve_undetermined_coefficients(eq, func, order, match)
def _solve_undetermined_coefficients(eq, func, order, match):
r"""
Helper function for the method of undetermined coefficients.
See the
:py:meth:`~sympy.solvers.ode.ode_nth_linear_constant_coeff_undetermined_coefficients`
docstring for more information on this method.
The parameter ``match`` should be a dictionary that has the following
keys:
``list``
A list of solutions to the homogeneous equation, such as the list
returned by
``ode_nth_linear_constant_coeff_homogeneous(returns='list')``.
``sol``
The general solution, such as the solution returned by
``ode_nth_linear_constant_coeff_homogeneous(returns='sol')``.
``trialset``
The set of trial functions as returned by
``_undetermined_coefficients_match()['trialset']``.
"""
x = func.args[0]
f = func.func
r = match
coeffs = numbered_symbols('a', cls=Dummy)
coefflist = []
gensols = r['list']
gsol = r['sol']
trialset = r['trialset']
notneedset = set([])
newtrialset = set([])
global collectterms
if len(gensols) != order:
raise NotImplementedError("Cannot find " + str(order) +
" solutions to the homogeneous equation necessary to apply" +
" undetermined coefficients to " + str(eq) +
" (number of terms != order)")
usedsin = set([])
mult = 0 # The multiplicity of the root
getmult = True
for i, reroot, imroot in collectterms:
if getmult:
mult = i + 1
getmult = False
if i == 0:
getmult = True
if imroot:
# Alternate between sin and cos
if (i, reroot) in usedsin:
check = x**i*exp(reroot*x)*cos(imroot*x)
else:
check = x**i*exp(reroot*x)*sin(abs(imroot)*x)
usedsin.add((i, reroot))
else:
check = x**i*exp(reroot*x)
if check in trialset:
# If an element of the trial function is already part of the
# homogeneous solution, we need to multiply by sufficient x to
# make it linearly independent. We also don't need to bother
# checking for the coefficients on those elements, since we
# already know it will be 0.
while True:
if check*x**mult in trialset:
mult += 1
else:
break
trialset.add(check*x**mult)
notneedset.add(check)
newtrialset = trialset - notneedset
trialfunc = 0
for i in newtrialset:
c = next(coeffs)
coefflist.append(c)
trialfunc += c*i
eqs = sub_func_doit(eq, f(x), trialfunc)
coeffsdict = dict(list(zip(trialset, [0]*(len(trialset) + 1))))
eqs = _mexpand(eqs)
for i in Add.make_args(eqs):
s = separatevars(i, dict=True, symbols=[x])
coeffsdict[s[x]] += s['coeff']
coeffvals = solve(list(coeffsdict.values()), coefflist)
if not coeffvals:
raise NotImplementedError(
"Could not solve `%s` using the "
"method of undetermined coefficients "
"(unable to solve for coefficients)." % eq)
psol = trialfunc.subs(coeffvals)
return Eq(f(x), gsol.rhs + psol)
def _undetermined_coefficients_match(expr, x):
r"""
Returns a trial function match if undetermined coefficients can be applied
to ``expr``, and ``None`` otherwise.
A trial expression can be found for an expression for use with the method
of undetermined coefficients if the expression is an
additive/multiplicative combination of constants, polynomials in `x` (the
independent variable of expr), `\sin(a x + b)`, `\cos(a x + b)`, and
`e^{a x}` terms (in other words, it has a finite number of linearly
independent derivatives).
Note that you may still need to multiply each term returned here by
sufficient `x` to make it linearly independent with the solutions to the
homogeneous equation.
This is intended for internal use by ``undetermined_coefficients`` hints.
SymPy currently has no way to convert `\sin^n(x) \cos^m(y)` into a sum of
only `\sin(a x)` and `\cos(b x)` terms, so these are not implemented. So,
for example, you will need to manually convert `\sin^2(x)` into `[1 +
\cos(2 x)]/2` to properly apply the method of undetermined coefficients on
it.
Examples
========
>>> from sympy import log, exp
>>> from sympy.solvers.ode import _undetermined_coefficients_match
>>> from sympy.abc import x
>>> _undetermined_coefficients_match(9*x*exp(x) + exp(-x), x)
{'test': True, 'trialset': {x*exp(x), exp(-x), exp(x)}}
>>> _undetermined_coefficients_match(log(x), x)
{'test': False}
"""
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x])
expr = powsimp(expr, combine='exp') # exp(x)*exp(2*x + 1) => exp(3*x + 1)
retdict = {}
def _test_term(expr, x):
r"""
Test if ``expr`` fits the proper form for undetermined coefficients.
"""
if not expr.has(x):
return True
elif expr.is_Add:
return all(_test_term(i, x) for i in expr.args)
elif expr.is_Mul:
if expr.has(sin, cos):
foundtrig = False
# Make sure that there is only one trig function in the args.
# See the docstring.
for i in expr.args:
if i.has(sin, cos):
if foundtrig:
return False
else:
foundtrig = True
return all(_test_term(i, x) for i in expr.args)
elif expr.is_Function:
if expr.func in (sin, cos, exp):
if expr.args[0].match(a*x + b):
return True
else:
return False
else:
return False
elif expr.is_Pow and expr.base.is_Symbol and expr.exp.is_Integer and \
expr.exp >= 0:
return True
elif expr.is_Pow and expr.base.is_number:
if expr.exp.match(a*x + b):
return True
else:
return False
elif expr.is_Symbol or expr.is_number:
return True
else:
return False
def _get_trial_set(expr, x, exprs=set([])):
r"""
Returns a set of trial terms for undetermined coefficients.
The idea behind undetermined coefficients is that the terms expression
repeat themselves after a finite number of derivatives, except for the
coefficients (they are linearly dependent). So if we collect these,
we should have the terms of our trial function.
"""
def _remove_coefficient(expr, x):
r"""
Returns the expression without a coefficient.
Similar to expr.as_independent(x)[1], except it only works
multiplicatively.
"""
term = S.One
if expr.is_Mul:
for i in expr.args:
if i.has(x):
term *= i
elif expr.has(x):
term = expr
return term
expr = expand_mul(expr)
if expr.is_Add:
for term in expr.args:
if _remove_coefficient(term, x) in exprs:
pass
else:
exprs.add(_remove_coefficient(term, x))
exprs = exprs.union(_get_trial_set(term, x, exprs))
else:
term = _remove_coefficient(expr, x)
tmpset = exprs.union({term})
oldset = set([])
while tmpset != oldset:
# If you get stuck in this loop, then _test_term is probably
# broken
oldset = tmpset.copy()
expr = expr.diff(x)
term = _remove_coefficient(expr, x)
if term.is_Add:
tmpset = tmpset.union(_get_trial_set(term, x, tmpset))
else:
tmpset.add(term)
exprs = tmpset
return exprs
retdict['test'] = _test_term(expr, x)
if retdict['test']:
# Try to generate a list of trial solutions that will have the
# undetermined coefficients. Note that if any of these are not linearly
# independent with any of the solutions to the homogeneous equation,
# then they will need to be multiplied by sufficient x to make them so.
# This function DOES NOT do that (it doesn't even look at the
# homogeneous equation).
retdict['trialset'] = _get_trial_set(expr, x)
return retdict
def ode_nth_linear_constant_coeff_variation_of_parameters(eq, func, order, match):
r"""
Solves an `n`\th order linear differential equation with constant
coefficients using the method of variation of parameters.
This method works on any differential equations of the form
.. math:: f^{(n)}(x) + a_{n-1} f^{(n-1)}(x) + \cdots + a_1 f'(x) + a_0
f(x) = P(x)\text{.}
This method works by assuming that the particular solution takes the form
.. math:: \sum_{x=1}^{n} c_i(x) y_i(x)\text{,}
where `y_i` is the `i`\th solution to the homogeneous equation. The
solution is then solved using Wronskian's and Cramer's Rule. The
particular solution is given by
.. math:: \sum_{x=1}^n \left( \int \frac{W_i(x)}{W(x)} \,dx
\right) y_i(x) \text{,}
where `W(x)` is the Wronskian of the fundamental system (the system of `n`
linearly independent solutions to the homogeneous equation), and `W_i(x)`
is the Wronskian of the fundamental system with the `i`\th column replaced
with `[0, 0, \cdots, 0, P(x)]`.
This method is general enough to solve any `n`\th order inhomogeneous
linear differential equation with constant coefficients, but sometimes
SymPy cannot simplify the Wronskian well enough to integrate it. If this
method hangs, try using the
``nth_linear_constant_coeff_variation_of_parameters_Integral`` hint and
simplifying the integrals manually. Also, prefer using
``nth_linear_constant_coeff_undetermined_coefficients`` when it
applies, because it doesn't use integration, making it faster and more
reliable.
Warning, using simplify=False with
'nth_linear_constant_coeff_variation_of_parameters' in
:py:meth:`~sympy.solvers.ode.dsolve` may cause it to hang, because it will
not attempt to simplify the Wronskian before integrating. It is
recommended that you only use simplify=False with
'nth_linear_constant_coeff_variation_of_parameters_Integral' for this
method, especially if the solution to the homogeneous equation has
trigonometric functions in it.
Examples
========
>>> from sympy import Function, dsolve, pprint, exp, log
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(f(x).diff(x, 3) - 3*f(x).diff(x, 2) +
... 3*f(x).diff(x) - f(x) - exp(x)*log(x), f(x),
... hint='nth_linear_constant_coeff_variation_of_parameters'))
/ 3 \
| 2 x *(6*log(x) - 11)| x
f(x) = |C1 + C2*x + C3*x + ------------------|*e
\ 36 /
References
==========
- https://en.wikipedia.org/wiki/Variation_of_parameters
- http://planetmath.org/VariationOfParameters
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 233
# indirect doctest
"""
gensol = ode_nth_linear_constant_coeff_homogeneous(eq, func, order, match,
returns='both')
match.update(gensol)
return _solve_variation_of_parameters(eq, func, order, match)
def _solve_variation_of_parameters(eq, func, order, match):
r"""
Helper function for the method of variation of parameters and nonhomogeneous euler eq.
See the
:py:meth:`~sympy.solvers.ode.ode_nth_linear_constant_coeff_variation_of_parameters`
docstring for more information on this method.
The parameter ``match`` should be a dictionary that has the following
keys:
``list``
A list of solutions to the homogeneous equation, such as the list
returned by
``ode_nth_linear_constant_coeff_homogeneous(returns='list')``.
``sol``
The general solution, such as the solution returned by
``ode_nth_linear_constant_coeff_homogeneous(returns='sol')``.
"""
x = func.args[0]
f = func.func
r = match
psol = 0
gensols = r['list']
gsol = r['sol']
wr = wronskian(gensols, x)
if r.get('simplify', True):
wr = simplify(wr) # We need much better simplification for
# some ODEs. See issue 4662, for example.
# To reduce commonly occurring sin(x)**2 + cos(x)**2 to 1
wr = trigsimp(wr, deep=True, recursive=True)
if not wr:
# The wronskian will be 0 iff the solutions are not linearly
# independent.
raise NotImplementedError("Cannot find " + str(order) +
" solutions to the homogeneous equation necessary to apply " +
"variation of parameters to " + str(eq) + " (Wronskian == 0)")
if len(gensols) != order:
raise NotImplementedError("Cannot find " + str(order) +
" solutions to the homogeneous equation necessary to apply " +
"variation of parameters to " +
str(eq) + " (number of terms != order)")
negoneterm = (-1)**(order)
for i in gensols:
psol += negoneterm*Integral(wronskian([sol for sol in gensols if sol != i], x)*r[-1]/wr, x)*i/r[order]
negoneterm *= -1
if r.get('simplify', True):
psol = simplify(psol)
psol = trigsimp(psol, deep=True)
return Eq(f(x), gsol.rhs + psol)
def ode_separable(eq, func, order, match):
r"""
Solves separable 1st order differential equations.
This is any differential equation that can be written as `P(y)
\tfrac{dy}{dx} = Q(x)`. The solution can then just be found by
rearranging terms and integrating: `\int P(y) \,dy = \int Q(x) \,dx`.
This hint uses :py:meth:`sympy.simplify.simplify.separatevars` as its back
end, so if a separable equation is not caught by this solver, it is most
likely the fault of that function.
:py:meth:`~sympy.simplify.simplify.separatevars` is
smart enough to do most expansion and factoring necessary to convert a
separable equation `F(x, y)` into the proper form `P(x)\cdot{}Q(y)`. The
general solution is::
>>> from sympy import Function, dsolve, Eq, pprint
>>> from sympy.abc import x
>>> a, b, c, d, f = map(Function, ['a', 'b', 'c', 'd', 'f'])
>>> genform = Eq(a(x)*b(f(x))*f(x).diff(x), c(x)*d(f(x)))
>>> pprint(genform)
d
a(x)*b(f(x))*--(f(x)) = c(x)*d(f(x))
dx
>>> pprint(dsolve(genform, f(x), hint='separable_Integral'))
f(x)
/ /
| |
| b(y) | c(x)
| ---- dy = C1 + | ---- dx
| d(y) | a(x)
| |
/ /
Examples
========
>>> from sympy import Function, dsolve, Eq
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(Eq(f(x)*f(x).diff(x) + x, 3*x*f(x)**2), f(x),
... hint='separable', simplify=False))
/ 2 \ 2
log\3*f (x) - 1/ x
---------------- = C1 + --
6 2
References
==========
- M. Tenenbaum & H. Pollard, "Ordinary Differential Equations",
Dover 1963, pp. 52
# indirect doctest
"""
x = func.args[0]
f = func.func
C1 = get_numbered_constants(eq, num=1)
r = match # {'m1':m1, 'm2':m2, 'y':y}
u = r.get('hint', f(x)) # get u from separable_reduced else get f(x)
return Eq(Integral(r['m2']['coeff']*r['m2'][r['y']]/r['m1'][r['y']],
(r['y'], None, u)), Integral(-r['m1']['coeff']*r['m1'][x]/
r['m2'][x], x) + C1)
def checkinfsol(eq, infinitesimals, func=None, order=None):
r"""
This function is used to check if the given infinitesimals are the
actual infinitesimals of the given first order differential equation.
This method is specific to the Lie Group Solver of ODEs.
As of now, it simply checks, by substituting the infinitesimals in the
partial differential equation.
.. math:: \frac{\partial \eta}{\partial x} + \left(\frac{\partial \eta}{\partial y}
- \frac{\partial \xi}{\partial x}\right)*h
- \frac{\partial \xi}{\partial y}*h^{2}
- \xi\frac{\partial h}{\partial x} - \eta\frac{\partial h}{\partial y} = 0
where `\eta`, and `\xi` are the infinitesimals and `h(x,y) = \frac{dy}{dx}`
The infinitesimals should be given in the form of a list of dicts
``[{xi(x, y): inf, eta(x, y): inf}]``, corresponding to the
output of the function infinitesimals. It returns a list
of values of the form ``[(True/False, sol)]`` where ``sol`` is the value
obtained after substituting the infinitesimals in the PDE. If it
is ``True``, then ``sol`` would be 0.
"""
if isinstance(eq, Equality):
eq = eq.lhs - eq.rhs
if not func:
eq, func = _preprocess(eq)
variables = func.args
if len(variables) != 1:
raise ValueError("ODE's have only one independent variable")
else:
x = variables[0]
if not order:
order = ode_order(eq, func)
if order != 1:
raise NotImplementedError("Lie groups solver has been implemented "
"only for first order differential equations")
else:
df = func.diff(x)
a = Wild('a', exclude = [df])
b = Wild('b', exclude = [df])
match = collect(expand(eq), df).match(a*df + b)
if match:
h = -simplify(match[b]/match[a])
else:
try:
sol = solve(eq, df)
except NotImplementedError:
raise NotImplementedError("Infinitesimals for the "
"first order ODE could not be found")
else:
h = sol[0] # Find infinitesimals for one solution
y = Dummy('y')
h = h.subs(func, y)
xi = Function('xi')(x, y)
eta = Function('eta')(x, y)
dxi = Function('xi')(x, func)
deta = Function('eta')(x, func)
pde = (eta.diff(x) + (eta.diff(y) - xi.diff(x))*h -
(xi.diff(y))*h**2 - xi*(h.diff(x)) - eta*(h.diff(y)))
soltup = []
for sol in infinitesimals:
tsol = {xi: S(sol[dxi]).subs(func, y),
eta: S(sol[deta]).subs(func, y)}
sol = simplify(pde.subs(tsol).doit())
if sol:
soltup.append((False, sol.subs(y, func)))
else:
soltup.append((True, 0))
return soltup
def ode_lie_group(eq, func, order, match):
r"""
This hint implements the Lie group method of solving first order differential
equations. The aim is to convert the given differential equation from the
given coordinate given system into another coordinate system where it becomes
invariant under the one-parameter Lie group of translations. The converted ODE is
quadrature and can be solved easily. It makes use of the
:py:meth:`sympy.solvers.ode.infinitesimals` function which returns the
infinitesimals of the transformation.
The coordinates `r` and `s` can be found by solving the following Partial
Differential Equations.
.. math :: \xi\frac{\partial r}{\partial x} + \eta\frac{\partial r}{\partial y}
= 0
.. math :: \xi\frac{\partial s}{\partial x} + \eta\frac{\partial s}{\partial y}
= 1
The differential equation becomes separable in the new coordinate system
.. math :: \frac{ds}{dr} = \frac{\frac{\partial s}{\partial x} +
h(x, y)\frac{\partial s}{\partial y}}{
\frac{\partial r}{\partial x} + h(x, y)\frac{\partial r}{\partial y}}
After finding the solution by integration, it is then converted back to the original
coordinate system by substituting `r` and `s` in terms of `x` and `y` again.
Examples
========
>>> from sympy import Function, dsolve, Eq, exp, pprint
>>> from sympy.abc import x
>>> f = Function('f')
>>> pprint(dsolve(f(x).diff(x) + 2*x*f(x) - x*exp(-x**2), f(x),
... hint='lie_group'))
/ 2\ 2
| x | -x
f(x) = |C1 + --|*e
\ 2 /
References
==========
- Solving differential equations by Symmetry Groups,
John Starrett, pp. 1 - pp. 14
"""
heuristics = lie_heuristics
inf = {}
f = func.func
x = func.args[0]
df = func.diff(x)
xi = Function("xi")
eta = Function("eta")
a = Wild('a', exclude = [df])
b = Wild('b', exclude = [df])
xis = match.pop('xi')
etas = match.pop('eta')
if match:
h = -simplify(match[match['d']]/match[match['e']])
y = match['y']
else:
try:
sol = solve(eq, df)
if sol == []:
raise NotImplementedError
except NotImplementedError:
raise NotImplementedError("Unable to solve the differential equation " +
str(eq) + " by the lie group method")
else:
y = Dummy("y")
h = sol[0].subs(func, y)
if xis is not None and etas is not None:
inf = [{xi(x, f(x)): S(xis), eta(x, f(x)): S(etas)}]
if not checkinfsol(eq, inf, func=f(x), order=1)[0][0]:
raise ValueError("The given infinitesimals xi and eta"
" are not the infinitesimals to the given equation")
else:
heuristics = ["user_defined"]
match = {'h': h, 'y': y}
# This is done so that if:
# a] solve raises a NotImplementedError.
# b] any heuristic raises a ValueError
# another heuristic can be used.
tempsol = [] # Used by solve below
for heuristic in heuristics:
try:
if not inf:
inf = infinitesimals(eq, hint=heuristic, func=func, order=1, match=match)
except ValueError:
continue
else:
for infsim in inf:
xiinf = (infsim[xi(x, func)]).subs(func, y)
etainf = (infsim[eta(x, func)]).subs(func, y)
# This condition creates recursion while using pdsolve.
# Since the first step while solving a PDE of form
# a*(f(x, y).diff(x)) + b*(f(x, y).diff(y)) + c = 0
# is to solve the ODE dy/dx = b/a
if simplify(etainf/xiinf) == h:
continue
rpde = f(x, y).diff(x)*xiinf + f(x, y).diff(y)*etainf
r = pdsolve(rpde, func=f(x, y)).rhs
s = pdsolve(rpde - 1, func=f(x, y)).rhs
newcoord = [_lie_group_remove(coord) for coord in [r, s]]
r = Dummy("r")
s = Dummy("s")
C1 = Symbol("C1")
rcoord = newcoord[0]
scoord = newcoord[-1]
try:
sol = solve([r - rcoord, s - scoord], x, y, dict=True)
except NotImplementedError:
continue
else:
sol = sol[0]
xsub = sol[x]
ysub = sol[y]
num = simplify(scoord.diff(x) + scoord.diff(y)*h)
denom = simplify(rcoord.diff(x) + rcoord.diff(y)*h)
if num and denom:
diffeq = simplify((num/denom).subs([(x, xsub), (y, ysub)]))
sep = separatevars(diffeq, symbols=[r, s], dict=True)
if sep:
# Trying to separate, r and s coordinates
deq = integrate((1/sep[s]), s) + C1 - integrate(sep['coeff']*sep[r], r)
# Substituting and reverting back to original coordinates
deq = deq.subs([(r, rcoord), (s, scoord)])
try:
sdeq = solve(deq, y)
except NotImplementedError:
tempsol.append(deq)
else:
if len(sdeq) == 1:
return Eq(f(x), sdeq.pop())
else:
return [Eq(f(x), sol) for sol in sdeq]
elif denom: # (ds/dr) is zero which means s is constant
return Eq(f(x), solve(scoord - C1, y)[0])
elif num: # (dr/ds) is zero which means r is constant
return Eq(f(x), solve(rcoord - C1, y)[0])
# If nothing works, return solution as it is, without solving for y
if tempsol:
if len(tempsol) == 1:
return Eq(tempsol.pop().subs(y, f(x)), 0)
else:
return [Eq(sol.subs(y, f(x)), 0) for sol in tempsol]
raise NotImplementedError("The given ODE " + str(eq) + " cannot be solved by"
+ " the lie group method")
def _lie_group_remove(coords):
r"""
This function is strictly meant for internal use by the Lie group ODE solving
method. It replaces arbitrary functions returned by pdsolve with either 0 or 1 or the
args of the arbitrary function.
The algorithm used is:
1] If coords is an instance of an Undefined Function, then the args are returned
2] If the arbitrary function is present in an Add object, it is replaced by zero.
3] If the arbitrary function is present in an Mul object, it is replaced by one.
4] If coords has no Undefined Function, it is returned as it is.
Examples
========
>>> from sympy.solvers.ode import _lie_group_remove
>>> from sympy import Function
>>> from sympy.abc import x, y
>>> F = Function("F")
>>> eq = x**2*y
>>> _lie_group_remove(eq)
x**2*y
>>> eq = F(x**2*y)
>>> _lie_group_remove(eq)
x**2*y
>>> eq = y**2*x + F(x**3)
>>> _lie_group_remove(eq)
x*y**2
>>> eq = (F(x**3) + y)*x**4
>>> _lie_group_remove(eq)
x**4*y
"""
if isinstance(coords, AppliedUndef):
return coords.args[0]
elif coords.is_Add:
subfunc = coords.atoms(AppliedUndef)
if subfunc:
for func in subfunc:
coords = coords.subs(func, 0)
return coords
elif coords.is_Pow:
base, expr = coords.as_base_exp()
base = _lie_group_remove(base)
expr = _lie_group_remove(expr)
return base**expr
elif coords.is_Mul:
mulargs = []
coordargs = coords.args
for arg in coordargs:
if not isinstance(coords, AppliedUndef):
mulargs.append(_lie_group_remove(arg))
return Mul(*mulargs)
return coords
def infinitesimals(eq, func=None, order=None, hint='default', match=None):
r"""
The infinitesimal functions of an ordinary differential equation, `\xi(x,y)`
and `\eta(x,y)`, are the infinitesimals of the Lie group of point transformations
for which the differential equation is invariant. So, the ODE `y'=f(x,y)`
would admit a Lie group `x^*=X(x,y;\varepsilon)=x+\varepsilon\xi(x,y)`,
`y^*=Y(x,y;\varepsilon)=y+\varepsilon\eta(x,y)` such that `(y^*)'=f(x^*, y^*)`.
A change of coordinates, to `r(x,y)` and `s(x,y)`, can be performed so this Lie group
becomes the translation group, `r^*=r` and `s^*=s+\varepsilon`.
They are tangents to the coordinate curves of the new system.
Consider the transformation `(x, y) \to (X, Y)` such that the
differential equation remains invariant. `\xi` and `\eta` are the tangents to
the transformed coordinates `X` and `Y`, at `\varepsilon=0`.
.. math:: \left(\frac{\partial X(x,y;\varepsilon)}{\partial\varepsilon
}\right)|_{\varepsilon=0} = \xi,
\left(\frac{\partial Y(x,y;\varepsilon)}{\partial\varepsilon
}\right)|_{\varepsilon=0} = \eta,
The infinitesimals can be found by solving the following PDE:
>>> from sympy import Function, diff, Eq, pprint
>>> from sympy.abc import x, y
>>> xi, eta, h = map(Function, ['xi', 'eta', 'h'])
>>> h = h(x, y) # dy/dx = h
>>> eta = eta(x, y)
>>> xi = xi(x, y)
>>> genform = Eq(eta.diff(x) + (eta.diff(y) - xi.diff(x))*h
... - (xi.diff(y))*h**2 - xi*(h.diff(x)) - eta*(h.diff(y)), 0)
>>> pprint(genform)
/d d \ d 2 d
|--(eta(x, y)) - --(xi(x, y))|*h(x, y) - eta(x, y)*--(h(x, y)) - h (x, y)*--(x
\dy dx / dy dy
<BLANKLINE>
d d
i(x, y)) - xi(x, y)*--(h(x, y)) + --(eta(x, y)) = 0
dx dx
Solving the above mentioned PDE is not trivial, and can be solved only by
making intelligent assumptions for `\xi` and `\eta` (heuristics). Once an
infinitesimal is found, the attempt to find more heuristics stops. This is done to
optimise the speed of solving the differential equation. If a list of all the
infinitesimals is needed, ``hint`` should be flagged as ``all``, which gives
the complete list of infinitesimals. If the infinitesimals for a particular
heuristic needs to be found, it can be passed as a flag to ``hint``.
Examples
========
>>> from sympy import Function, diff
>>> from sympy.solvers.ode import infinitesimals
>>> from sympy.abc import x
>>> f = Function('f')
>>> eq = f(x).diff(x) - x**2*f(x)
>>> infinitesimals(eq)
[{eta(x, f(x)): exp(x**3/3), xi(x, f(x)): 0}]
References
==========
- Solving differential equations by Symmetry Groups,
John Starrett, pp. 1 - pp. 14
"""
if isinstance(eq, Equality):
eq = eq.lhs - eq.rhs
if not func:
eq, func = _preprocess(eq)
variables = func.args
if len(variables) != 1:
raise ValueError("ODE's have only one independent variable")
else:
x = variables[0]
if not order:
order = ode_order(eq, func)
if order != 1:
raise NotImplementedError("Infinitesimals for only "
"first order ODE's have been implemented")
else:
df = func.diff(x)
# Matching differential equation of the form a*df + b
a = Wild('a', exclude = [df])
b = Wild('b', exclude = [df])
if match: # Used by lie_group hint
h = match['h']
y = match['y']
else:
match = collect(expand(eq), df).match(a*df + b)
if match:
h = -simplify(match[b]/match[a])
else:
try:
sol = solve(eq, df)
except NotImplementedError:
raise NotImplementedError("Infinitesimals for the "
"first order ODE could not be found")
else:
h = sol[0] # Find infinitesimals for one solution
y = Dummy("y")
h = h.subs(func, y)
u = Dummy("u")
hx = h.diff(x)
hy = h.diff(y)
hinv = ((1/h).subs([(x, u), (y, x)])).subs(u, y) # Inverse ODE
match = {'h': h, 'func': func, 'hx': hx, 'hy': hy, 'y': y, 'hinv': hinv}
if hint == 'all':
xieta = []
for heuristic in lie_heuristics:
function = globals()['lie_heuristic_' + heuristic]
inflist = function(match, comp=True)
if inflist:
xieta.extend([inf for inf in inflist if inf not in xieta])
if xieta:
return xieta
else:
raise NotImplementedError("Infinitesimals could not be found for "
"the given ODE")
elif hint == 'default':
for heuristic in lie_heuristics:
function = globals()['lie_heuristic_' + heuristic]
xieta = function(match, comp=False)
if xieta:
return xieta
raise NotImplementedError("Infinitesimals could not be found for"
" the given ODE")
elif hint not in lie_heuristics:
raise ValueError("Heuristic not recognized: " + hint)
else:
function = globals()['lie_heuristic_' + hint]
xieta = function(match, comp=True)
if xieta:
return xieta
else:
raise ValueError("Infinitesimals could not be found using the"
" given heuristic")
def lie_heuristic_abaco1_simple(match, comp=False):
r"""
The first heuristic uses the following four sets of
assumptions on `\xi` and `\eta`
.. math:: \xi = 0, \eta = f(x)
.. math:: \xi = 0, \eta = f(y)
.. math:: \xi = f(x), \eta = 0
.. math:: \xi = f(y), \eta = 0
The success of this heuristic is determined by algebraic factorisation.
For the first assumption `\xi = 0` and `\eta` to be a function of `x`, the PDE
.. math:: \frac{\partial \eta}{\partial x} + (\frac{\partial \eta}{\partial y}
- \frac{\partial \xi}{\partial x})*h
- \frac{\partial \xi}{\partial y}*h^{2}
- \xi*\frac{\partial h}{\partial x} - \eta*\frac{\partial h}{\partial y} = 0
reduces to `f'(x) - f\frac{\partial h}{\partial y} = 0`
If `\frac{\partial h}{\partial y}` is a function of `x`, then this can usually
be integrated easily. A similar idea is applied to the other 3 assumptions as well.
References
==========
- E.S Cheb-Terrab, L.G.S Duarte and L.A,C.P da Mota, Computer Algebra
Solving of First Order ODEs Using Symmetry Methods, pp. 8
"""
xieta = []
y = match['y']
h = match['h']
func = match['func']
x = func.args[0]
hx = match['hx']
hy = match['hy']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
hysym = hy.free_symbols
if y not in hysym:
try:
fx = exp(integrate(hy, x))
except NotImplementedError:
pass
else:
inf = {xi: S(0), eta: fx}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
factor = hy/h
facsym = factor.free_symbols
if x not in facsym:
try:
fy = exp(integrate(factor, y))
except NotImplementedError:
pass
else:
inf = {xi: S(0), eta: fy.subs(y, func)}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
factor = -hx/h
facsym = factor.free_symbols
if y not in facsym:
try:
fx = exp(integrate(factor, x))
except NotImplementedError:
pass
else:
inf = {xi: fx, eta: S(0)}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
factor = -hx/(h**2)
facsym = factor.free_symbols
if x not in facsym:
try:
fy = exp(integrate(factor, y))
except NotImplementedError:
pass
else:
inf = {xi: fy.subs(y, func), eta: S(0)}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
if xieta:
return xieta
def lie_heuristic_abaco1_product(match, comp=False):
r"""
The second heuristic uses the following two assumptions on `\xi` and `\eta`
.. math:: \eta = 0, \xi = f(x)*g(y)
.. math:: \eta = f(x)*g(y), \xi = 0
The first assumption of this heuristic holds good if
`\frac{1}{h^{2}}\frac{\partial^2}{\partial x \partial y}\log(h)` is
separable in `x` and `y`, then the separated factors containing `x`
is `f(x)`, and `g(y)` is obtained by
.. math:: e^{\int f\frac{\partial}{\partial x}\left(\frac{1}{f*h}\right)\,dy}
provided `f\frac{\partial}{\partial x}\left(\frac{1}{f*h}\right)` is a function
of `y` only.
The second assumption holds good if `\frac{dy}{dx} = h(x, y)` is rewritten as
`\frac{dy}{dx} = \frac{1}{h(y, x)}` and the same properties of the first assumption
satisfies. After obtaining `f(x)` and `g(y)`, the coordinates are again
interchanged, to get `\eta` as `f(x)*g(y)`
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 7 - pp. 8
"""
xieta = []
y = match['y']
h = match['h']
hinv = match['hinv']
func = match['func']
x = func.args[0]
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
inf = separatevars(((log(h).diff(y)).diff(x))/h**2, dict=True, symbols=[x, y])
if inf and inf['coeff']:
fx = inf[x]
gy = simplify(fx*((1/(fx*h)).diff(x)))
gysyms = gy.free_symbols
if x not in gysyms:
gy = exp(integrate(gy, y))
inf = {eta: S(0), xi: (fx*gy).subs(y, func)}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
u1 = Dummy("u1")
inf = separatevars(((log(hinv).diff(y)).diff(x))/hinv**2, dict=True, symbols=[x, y])
if inf and inf['coeff']:
fx = inf[x]
gy = simplify(fx*((1/(fx*hinv)).diff(x)))
gysyms = gy.free_symbols
if x not in gysyms:
gy = exp(integrate(gy, y))
etaval = fx*gy
etaval = (etaval.subs([(x, u1), (y, x)])).subs(u1, y)
inf = {eta: etaval.subs(y, func), xi: S(0)}
if not comp:
return [inf]
if comp and inf not in xieta:
xieta.append(inf)
if xieta:
return xieta
def lie_heuristic_bivariate(match, comp=False):
r"""
The third heuristic assumes the infinitesimals `\xi` and `\eta`
to be bi-variate polynomials in `x` and `y`. The assumption made here
for the logic below is that `h` is a rational function in `x` and `y`
though that may not be necessary for the infinitesimals to be
bivariate polynomials. The coefficients of the infinitesimals
are found out by substituting them in the PDE and grouping similar terms
that are polynomials and since they form a linear system, solve and check
for non trivial solutions. The degree of the assumed bivariates
are increased till a certain maximum value.
References
==========
- Lie Groups and Differential Equations
pp. 327 - pp. 329
"""
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
if h.is_rational_function():
# The maximum degree that the infinitesimals can take is
# calculated by this technique.
etax, etay, etad, xix, xiy, xid = symbols("etax etay etad xix xiy xid")
ipde = etax + (etay - xix)*h - xiy*h**2 - xid*hx - etad*hy
num, denom = cancel(ipde).as_numer_denom()
deg = Poly(num, x, y).total_degree()
deta = Function('deta')(x, y)
dxi = Function('dxi')(x, y)
ipde = (deta.diff(x) + (deta.diff(y) - dxi.diff(x))*h - (dxi.diff(y))*h**2
- dxi*hx - deta*hy)
xieq = Symbol("xi0")
etaeq = Symbol("eta0")
for i in range(deg + 1):
if i:
xieq += Add(*[
Symbol("xi_" + str(power) + "_" + str(i - power))*x**power*y**(i - power)
for power in range(i + 1)])
etaeq += Add(*[
Symbol("eta_" + str(power) + "_" + str(i - power))*x**power*y**(i - power)
for power in range(i + 1)])
pden, denom = (ipde.subs({dxi: xieq, deta: etaeq}).doit()).as_numer_denom()
pden = expand(pden)
# If the individual terms are monomials, the coefficients
# are grouped
if pden.is_polynomial(x, y) and pden.is_Add:
polyy = Poly(pden, x, y).as_dict()
if polyy:
symset = xieq.free_symbols.union(etaeq.free_symbols) - {x, y}
soldict = solve(polyy.values(), *symset)
if isinstance(soldict, list):
soldict = soldict[0]
if any(x for x in soldict.values()):
xired = xieq.subs(soldict)
etared = etaeq.subs(soldict)
# Scaling is done by substituting one for the parameters
# This can be any number except zero.
dict_ = dict((sym, 1) for sym in symset)
inf = {eta: etared.subs(dict_).subs(y, func),
xi: xired.subs(dict_).subs(y, func)}
return [inf]
def lie_heuristic_chi(match, comp=False):
r"""
The aim of the fourth heuristic is to find the function `\chi(x, y)`
that satisfies the PDE `\frac{d\chi}{dx} + h\frac{d\chi}{dx}
- \frac{\partial h}{\partial y}\chi = 0`.
This assumes `\chi` to be a bivariate polynomial in `x` and `y`. By intuition,
`h` should be a rational function in `x` and `y`. The method used here is
to substitute a general binomial for `\chi` up to a certain maximum degree
is reached. The coefficients of the polynomials, are calculated by by collecting
terms of the same order in `x` and `y`.
After finding `\chi`, the next step is to use `\eta = \xi*h + \chi`, to
determine `\xi` and `\eta`. This can be done by dividing `\chi` by `h`
which would give `-\xi` as the quotient and `\eta` as the remainder.
References
==========
- E.S Cheb-Terrab, L.G.S Duarte and L.A,C.P da Mota, Computer Algebra
Solving of First Order ODEs Using Symmetry Methods, pp. 8
"""
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
if h.is_rational_function():
schi, schix, schiy = symbols("schi, schix, schiy")
cpde = schix + h*schiy - hy*schi
num, denom = cancel(cpde).as_numer_denom()
deg = Poly(num, x, y).total_degree()
chi = Function('chi')(x, y)
chix = chi.diff(x)
chiy = chi.diff(y)
cpde = chix + h*chiy - hy*chi
chieq = Symbol("chi")
for i in range(1, deg + 1):
chieq += Add(*[
Symbol("chi_" + str(power) + "_" + str(i - power))*x**power*y**(i - power)
for power in range(i + 1)])
cnum, cden = cancel(cpde.subs({chi : chieq}).doit()).as_numer_denom()
cnum = expand(cnum)
if cnum.is_polynomial(x, y) and cnum.is_Add:
cpoly = Poly(cnum, x, y).as_dict()
if cpoly:
solsyms = chieq.free_symbols - {x, y}
soldict = solve(cpoly.values(), *solsyms)
if isinstance(soldict, list):
soldict = soldict[0]
if any(x for x in soldict.values()):
chieq = chieq.subs(soldict)
dict_ = dict((sym, 1) for sym in solsyms)
chieq = chieq.subs(dict_)
# After finding chi, the main aim is to find out
# eta, xi by the equation eta = xi*h + chi
# One method to set xi, would be rearranging it to
# (eta/h) - xi = (chi/h). This would mean dividing
# chi by h would give -xi as the quotient and eta
# as the remainder. Thanks to Sean Vig for suggesting
# this method.
xic, etac = div(chieq, h)
inf = {eta: etac.subs(y, func), xi: -xic.subs(y, func)}
return [inf]
def lie_heuristic_function_sum(match, comp=False):
r"""
This heuristic uses the following two assumptions on `\xi` and `\eta`
.. math:: \eta = 0, \xi = f(x) + g(y)
.. math:: \eta = f(x) + g(y), \xi = 0
The first assumption of this heuristic holds good if
.. math:: \frac{\partial}{\partial y}[(h\frac{\partial^{2}}{
\partial x^{2}}(h^{-1}))^{-1}]
is separable in `x` and `y`,
1. The separated factors containing `y` is `\frac{\partial g}{\partial y}`.
From this `g(y)` can be determined.
2. The separated factors containing `x` is `f''(x)`.
3. `h\frac{\partial^{2}}{\partial x^{2}}(h^{-1})` equals
`\frac{f''(x)}{f(x) + g(y)}`. From this `f(x)` can be determined.
The second assumption holds good if `\frac{dy}{dx} = h(x, y)` is rewritten as
`\frac{dy}{dx} = \frac{1}{h(y, x)}` and the same properties of the first
assumption satisfies. After obtaining `f(x)` and `g(y)`, the coordinates
are again interchanged, to get `\eta` as `f(x) + g(y)`.
For both assumptions, the constant factors are separated among `g(y)`
and `f''(x)`, such that `f''(x)` obtained from 3] is the same as that
obtained from 2]. If not possible, then this heuristic fails.
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 7 - pp. 8
"""
xieta = []
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
hinv = match['hinv']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
for odefac in [h, hinv]:
factor = odefac*((1/odefac).diff(x, 2))
sep = separatevars((1/factor).diff(y), dict=True, symbols=[x, y])
if sep and sep['coeff'] and sep[x].has(x) and sep[y].has(y):
k = Dummy("k")
try:
gy = k*integrate(sep[y], y)
except NotImplementedError:
pass
else:
fdd = 1/(k*sep[x]*sep['coeff'])
fx = simplify(fdd/factor - gy)
check = simplify(fx.diff(x, 2) - fdd)
if fx:
if not check:
fx = fx.subs(k, 1)
gy = (gy/k)
else:
sol = solve(check, k)
if sol:
sol = sol[0]
fx = fx.subs(k, sol)
gy = (gy/k)*sol
else:
continue
if odefac == hinv: # Inverse ODE
fx = fx.subs(x, y)
gy = gy.subs(y, x)
etaval = factor_terms(fx + gy)
if etaval.is_Mul:
etaval = Mul(*[arg for arg in etaval.args if arg.has(x, y)])
if odefac == hinv: # Inverse ODE
inf = {eta: etaval.subs(y, func), xi : S(0)}
else:
inf = {xi: etaval.subs(y, func), eta : S(0)}
if not comp:
return [inf]
else:
xieta.append(inf)
if xieta:
return xieta
def lie_heuristic_abaco2_similar(match, comp=False):
r"""
This heuristic uses the following two assumptions on `\xi` and `\eta`
.. math:: \eta = g(x), \xi = f(x)
.. math:: \eta = f(y), \xi = g(y)
For the first assumption,
1. First `\frac{\frac{\partial h}{\partial y}}{\frac{\partial^{2} h}{
\partial yy}}` is calculated. Let us say this value is A
2. If this is constant, then `h` is matched to the form `A(x) + B(x)e^{
\frac{y}{C}}` then, `\frac{e^{\int \frac{A(x)}{C} \,dx}}{B(x)}` gives `f(x)`
and `A(x)*f(x)` gives `g(x)`
3. Otherwise `\frac{\frac{\partial A}{\partial X}}{\frac{\partial A}{
\partial Y}} = \gamma` is calculated. If
a] `\gamma` is a function of `x` alone
b] `\frac{\gamma\frac{\partial h}{\partial y} - \gamma'(x) - \frac{
\partial h}{\partial x}}{h + \gamma} = G` is a function of `x` alone.
then, `e^{\int G \,dx}` gives `f(x)` and `-\gamma*f(x)` gives `g(x)`
The second assumption holds good if `\frac{dy}{dx} = h(x, y)` is rewritten as
`\frac{dy}{dx} = \frac{1}{h(y, x)}` and the same properties of the first assumption
satisfies. After obtaining `f(x)` and `g(x)`, the coordinates are again
interchanged, to get `\xi` as `f(x^*)` and `\eta` as `g(y^*)`
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 10 - pp. 12
"""
xieta = []
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
hinv = match['hinv']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
factor = cancel(h.diff(y)/h.diff(y, 2))
factorx = factor.diff(x)
factory = factor.diff(y)
if not factor.has(x) and not factor.has(y):
A = Wild('A', exclude=[y])
B = Wild('B', exclude=[y])
C = Wild('C', exclude=[x, y])
match = h.match(A + B*exp(y/C))
try:
tau = exp(-integrate(match[A]/match[C]), x)/match[B]
except NotImplementedError:
pass
else:
gx = match[A]*tau
return [{xi: tau, eta: gx}]
else:
gamma = cancel(factorx/factory)
if not gamma.has(y):
tauint = cancel((gamma*hy - gamma.diff(x) - hx)/(h + gamma))
if not tauint.has(y):
try:
tau = exp(integrate(tauint, x))
except NotImplementedError:
pass
else:
gx = -tau*gamma
return [{xi: tau, eta: gx}]
factor = cancel(hinv.diff(y)/hinv.diff(y, 2))
factorx = factor.diff(x)
factory = factor.diff(y)
if not factor.has(x) and not factor.has(y):
A = Wild('A', exclude=[y])
B = Wild('B', exclude=[y])
C = Wild('C', exclude=[x, y])
match = h.match(A + B*exp(y/C))
try:
tau = exp(-integrate(match[A]/match[C]), x)/match[B]
except NotImplementedError:
pass
else:
gx = match[A]*tau
return [{eta: tau.subs(x, func), xi: gx.subs(x, func)}]
else:
gamma = cancel(factorx/factory)
if not gamma.has(y):
tauint = cancel((gamma*hinv.diff(y) - gamma.diff(x) - hinv.diff(x))/(
hinv + gamma))
if not tauint.has(y):
try:
tau = exp(integrate(tauint, x))
except NotImplementedError:
pass
else:
gx = -tau*gamma
return [{eta: tau.subs(x, func), xi: gx.subs(x, func)}]
def lie_heuristic_abaco2_unique_unknown(match, comp=False):
r"""
This heuristic assumes the presence of unknown functions or known functions
with non-integer powers.
1. A list of all functions and non-integer powers containing x and y
2. Loop over each element `f` in the list, find `\frac{\frac{\partial f}{\partial x}}{
\frac{\partial f}{\partial x}} = R`
If it is separable in `x` and `y`, let `X` be the factors containing `x`. Then
a] Check if `\xi = X` and `\eta = -\frac{X}{R}` satisfy the PDE. If yes, then return
`\xi` and `\eta`
b] Check if `\xi = \frac{-R}{X}` and `\eta = -\frac{1}{X}` satisfy the PDE.
If yes, then return `\xi` and `\eta`
If not, then check if
a] :math:`\xi = -R,\eta = 1`
b] :math:`\xi = 1, \eta = -\frac{1}{R}`
are solutions.
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 10 - pp. 12
"""
xieta = []
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
hinv = match['hinv']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
funclist = []
for atom in h.atoms(Pow):
base, exp = atom.as_base_exp()
if base.has(x) and base.has(y):
if not exp.is_Integer:
funclist.append(atom)
for function in h.atoms(AppliedUndef):
syms = function.free_symbols
if x in syms and y in syms:
funclist.append(function)
for f in funclist:
frac = cancel(f.diff(y)/f.diff(x))
sep = separatevars(frac, dict=True, symbols=[x, y])
if sep and sep['coeff']:
xitry1 = sep[x]
etatry1 = -1/(sep[y]*sep['coeff'])
pde1 = etatry1.diff(y)*h - xitry1.diff(x)*h - xitry1*hx - etatry1*hy
if not simplify(pde1):
return [{xi: xitry1, eta: etatry1.subs(y, func)}]
xitry2 = 1/etatry1
etatry2 = 1/xitry1
pde2 = etatry2.diff(x) - (xitry2.diff(y))*h**2 - xitry2*hx - etatry2*hy
if not simplify(expand(pde2)):
return [{xi: xitry2.subs(y, func), eta: etatry2}]
else:
etatry = -1/frac
pde = etatry.diff(x) + etatry.diff(y)*h - hx - etatry*hy
if not simplify(pde):
return [{xi: S(1), eta: etatry.subs(y, func)}]
xitry = -frac
pde = -xitry.diff(x)*h -xitry.diff(y)*h**2 - xitry*hx -hy
if not simplify(expand(pde)):
return [{xi: xitry.subs(y, func), eta: S(1)}]
def lie_heuristic_abaco2_unique_general(match, comp=False):
r"""
This heuristic finds if infinitesimals of the form `\eta = f(x)`, `\xi = g(y)`
without making any assumptions on `h`.
The complete sequence of steps is given in the paper mentioned below.
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 10 - pp. 12
"""
xieta = []
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
hinv = match['hinv']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
C = S(0)
A = hx.diff(y)
B = hy.diff(y) + hy**2
C = hx.diff(x) - hx**2
if not (A and B and C):
return
Ax = A.diff(x)
Ay = A.diff(y)
Axy = Ax.diff(y)
Axx = Ax.diff(x)
Ayy = Ay.diff(y)
D = simplify(2*Axy + hx*Ay - Ax*hy + (hx*hy + 2*A)*A)*A - 3*Ax*Ay
if not D:
E1 = simplify(3*Ax**2 + ((hx**2 + 2*C)*A - 2*Axx)*A)
if E1:
E2 = simplify((2*Ayy + (2*B - hy**2)*A)*A - 3*Ay**2)
if not E2:
E3 = simplify(
E1*((28*Ax + 4*hx*A)*A**3 - E1*(hy*A + Ay)) - E1.diff(x)*8*A**4)
if not E3:
etaval = cancel((4*A**3*(Ax - hx*A) + E1*(hy*A - Ay))/(S(2)*A*E1))
if x not in etaval:
try:
etaval = exp(integrate(etaval, y))
except NotImplementedError:
pass
else:
xival = -4*A**3*etaval/E1
if y not in xival:
return [{xi: xival, eta: etaval.subs(y, func)}]
else:
E1 = simplify((2*Ayy + (2*B - hy**2)*A)*A - 3*Ay**2)
if E1:
E2 = simplify(
4*A**3*D - D**2 + E1*((2*Axx - (hx**2 + 2*C)*A)*A - 3*Ax**2))
if not E2:
E3 = simplify(
-(A*D)*E1.diff(y) + ((E1.diff(x) - hy*D)*A + 3*Ay*D +
(A*hx - 3*Ax)*E1)*E1)
if not E3:
etaval = cancel(((A*hx - Ax)*E1 - (Ay + A*hy)*D)/(S(2)*A*D))
if x not in etaval:
try:
etaval = exp(integrate(etaval, y))
except NotImplementedError:
pass
else:
xival = -E1*etaval/D
if y not in xival:
return [{xi: xival, eta: etaval.subs(y, func)}]
def lie_heuristic_linear(match, comp=False):
r"""
This heuristic assumes
1. `\xi = ax + by + c` and
2. `\eta = fx + gy + h`
After substituting the following assumptions in the determining PDE, it
reduces to
.. math:: f + (g - a)h - bh^{2} - (ax + by + c)\frac{\partial h}{\partial x}
- (fx + gy + c)\frac{\partial h}{\partial y}
Solving the reduced PDE obtained, using the method of characteristics, becomes
impractical. The method followed is grouping similar terms and solving the system
of linear equations obtained. The difference between the bivariate heuristic is that
`h` need not be a rational function in this case.
References
==========
- E.S. Cheb-Terrab, A.D. Roche, Symmetries and First Order
ODE Patterns, pp. 10 - pp. 12
"""
xieta = []
h = match['h']
hx = match['hx']
hy = match['hy']
func = match['func']
hinv = match['hinv']
x = func.args[0]
y = match['y']
xi = Function('xi')(x, func)
eta = Function('eta')(x, func)
coeffdict = {}
symbols = numbered_symbols("c", cls=Dummy)
symlist = [next(symbols) for i in islice(symbols, 6)]
C0, C1, C2, C3, C4, C5 = symlist
pde = C3 + (C4 - C0)*h -(C0*x + C1*y + C2)*hx - (C3*x + C4*y + C5)*hy - C1*h**2
pde, denom = pde.as_numer_denom()
pde = powsimp(expand(pde))
if pde.is_Add:
terms = pde.args
for term in terms:
if term.is_Mul:
rem = Mul(*[m for m in term.args if not m.has(x, y)])
xypart = term/rem
if xypart not in coeffdict:
coeffdict[xypart] = rem
else:
coeffdict[xypart] += rem
else:
if term not in coeffdict:
coeffdict[term] = S(1)
else:
coeffdict[term] += S(1)
sollist = coeffdict.values()
soldict = solve(sollist, symlist)
if soldict:
if isinstance(soldict, list):
soldict = soldict[0]
subval = soldict.values()
if any(t for t in subval):
onedict = dict(zip(symlist, [1]*6))
xival = C0*x + C1*func + C2
etaval = C3*x + C4*func + C5
xival = xival.subs(soldict)
etaval = etaval.subs(soldict)
xival = xival.subs(onedict)
etaval = etaval.subs(onedict)
return [{xi: xival, eta: etaval}]
def sysode_linear_2eq_order1(match_):
x = match_['func'][0].func
y = match_['func'][1].func
func = match_['func']
fc = match_['func_coeff']
eq = match_['eq']
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
r = dict()
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
for i in range(2):
eqs = 0
for terms in Add.make_args(eq[i]):
eqs += terms/fc[i,func[i],1]
eq[i] = eqs
# for equations Eq(a1*diff(x(t),t), a*x(t) + b*y(t) + k1)
# and Eq(a2*diff(x(t),t), c*x(t) + d*y(t) + k2)
r['a'] = -fc[0,x(t),0]/fc[0,x(t),1]
r['c'] = -fc[1,x(t),0]/fc[1,y(t),1]
r['b'] = -fc[0,y(t),0]/fc[0,x(t),1]
r['d'] = -fc[1,y(t),0]/fc[1,y(t),1]
forcing = [S(0),S(0)]
for i in range(2):
for j in Add.make_args(eq[i]):
if not j.has(x(t), y(t)):
forcing[i] += j
if not (forcing[0].has(t) or forcing[1].has(t)):
r['k1'] = forcing[0]
r['k2'] = forcing[1]
else:
raise NotImplementedError("Only homogeneous problems are supported" +
" (and constant inhomogeneity)")
if match_['type_of_equation'] == 'type1':
sol = _linear_2eq_order1_type1(x, y, t, r, eq)
if match_['type_of_equation'] == 'type2':
gsol = _linear_2eq_order1_type1(x, y, t, r, eq)
psol = _linear_2eq_order1_type2(x, y, t, r, eq)
sol = [Eq(x(t), gsol[0].rhs+psol[0]), Eq(y(t), gsol[1].rhs+psol[1])]
if match_['type_of_equation'] == 'type3':
sol = _linear_2eq_order1_type3(x, y, t, r, eq)
if match_['type_of_equation'] == 'type4':
sol = _linear_2eq_order1_type4(x, y, t, r, eq)
if match_['type_of_equation'] == 'type5':
sol = _linear_2eq_order1_type5(x, y, t, r, eq)
if match_['type_of_equation'] == 'type6':
sol = _linear_2eq_order1_type6(x, y, t, r, eq)
if match_['type_of_equation'] == 'type7':
sol = _linear_2eq_order1_type7(x, y, t, r, eq)
return sol
def _linear_2eq_order1_type1(x, y, t, r, eq):
r"""
It is classified under system of two linear homogeneous first-order constant-coefficient
ordinary differential equations.
The equations which come under this type are
.. math:: x' = ax + by,
.. math:: y' = cx + dy
The characteristics equation is written as
.. math:: \lambda^{2} + (a+d) \lambda + ad - bc = 0
and its discriminant is `D = (a-d)^{2} + 4bc`. There are several cases
1. Case when `ad - bc \neq 0`. The origin of coordinates, `x = y = 0`,
is the only stationary point; it is
- a node if `D = 0`
- a node if `D > 0` and `ad - bc > 0`
- a saddle if `D > 0` and `ad - bc < 0`
- a focus if `D < 0` and `a + d \neq 0`
- a centre if `D < 0` and `a + d \neq 0`.
1.1. If `D > 0`. The characteristic equation has two distinct real roots
`\lambda_1` and `\lambda_ 2` . The general solution of the system in question is expressed as
.. math:: x = C_1 b e^{\lambda_1 t} + C_2 b e^{\lambda_2 t}
.. math:: y = C_1 (\lambda_1 - a) e^{\lambda_1 t} + C_2 (\lambda_2 - a) e^{\lambda_2 t}
where `C_1` and `C_2` being arbitrary constants
1.2. If `D < 0`. The characteristics equation has two conjugate
roots, `\lambda_1 = \sigma + i \beta` and `\lambda_2 = \sigma - i \beta`.
The general solution of the system is given by
.. math:: x = b e^{\sigma t} (C_1 \sin(\beta t) + C_2 \cos(\beta t))
.. math:: y = e^{\sigma t} ([(\sigma - a) C_1 - \beta C_2] \sin(\beta t) + [\beta C_1 + (\sigma - a) C_2 \cos(\beta t)])
1.3. If `D = 0` and `a \neq d`. The characteristic equation has
two equal roots, `\lambda_1 = \lambda_2`. The general solution of the system is written as
.. math:: x = 2b (C_1 + \frac{C_2}{a-d} + C_2 t) e^{\frac{a+d}{2} t}
.. math:: y = [(d - a) C_1 + C_2 + (d - a) C_2 t] e^{\frac{a+d}{2} t}
1.4. If `D = 0` and `a = d \neq 0` and `b = 0`
.. math:: x = C_1 e^{a t} , y = (c C_1 t + C_2) e^{a t}
1.5. If `D = 0` and `a = d \neq 0` and `c = 0`
.. math:: x = (b C_1 t + C_2) e^{a t} , y = C_1 e^{a t}
2. Case when `ad - bc = 0` and `a^{2} + b^{2} > 0`. The whole straight
line `ax + by = 0` consists of singular points. The original system of differential
equations can be rewritten as
.. math:: x' = ax + by , y' = k (ax + by)
2.1 If `a + bk \neq 0`, solution will be
.. math:: x = b C_1 + C_2 e^{(a + bk) t} , y = -a C_1 + k C_2 e^{(a + bk) t}
2.2 If `a + bk = 0`, solution will be
.. math:: x = C_1 (bk t - 1) + b C_2 t , y = k^{2} b C_1 t + (b k^{2} t + 1) C_2
"""
l = Dummy('l')
C1, C2 = get_numbered_constants(eq, num=2)
a, b, c, d = r['a'], r['b'], r['c'], r['d']
real_coeff = all(v.is_real for v in (a, b, c, d))
D = (a - d)**2 + 4*b*c
l1 = (a + d + sqrt(D))/2
l2 = (a + d - sqrt(D))/2
equal_roots = Eq(D, 0).expand()
gsol1, gsol2 = [], []
# Solutions have exponential form if either D > 0 with real coefficients
# or D != 0 with complex coefficients. Eigenvalues are distinct.
# For each eigenvalue lam, pick an eigenvector, making sure we don't get (0, 0)
# The candidates are (b, lam-a) and (lam-d, c).
exponential_form = D > 0 if real_coeff else Not(equal_roots)
bad_ab_vector1 = And(Eq(b, 0), Eq(l1, a))
bad_ab_vector2 = And(Eq(b, 0), Eq(l2, a))
vector1 = Matrix((Piecewise((l1 - d, bad_ab_vector1), (b, True)),
Piecewise((c, bad_ab_vector1), (l1 - a, True))))
vector2 = Matrix((Piecewise((l2 - d, bad_ab_vector2), (b, True)),
Piecewise((c, bad_ab_vector2), (l2 - a, True))))
sol_vector = C1*exp(l1*t)*vector1 + C2*exp(l2*t)*vector2
gsol1.append((sol_vector[0], exponential_form))
gsol2.append((sol_vector[1], exponential_form))
# Solutions have trigonometric form for real coefficients with D < 0
# Both b and c are nonzero in this case, so (b, lam-a) is an eigenvector
# It splits into real/imag parts as (b, sigma-a) and (0, beta). Then
# multiply it by C1(cos(beta*t) + I*C2*sin(beta*t)) and separate real/imag
trigonometric_form = D < 0 if real_coeff else False
sigma = re(l1)
if im(l1).is_positive:
beta = im(l1)
else:
beta = im(l2)
vector1 = Matrix((b, sigma - a))
vector2 = Matrix((0, beta))
sol_vector = exp(sigma*t) * (C1*(cos(beta*t)*vector1 - sin(beta*t)*vector2) + \
C2*(sin(beta*t)*vector1 + cos(beta*t)*vector2))
gsol1.append((sol_vector[0], trigonometric_form))
gsol2.append((sol_vector[1], trigonometric_form))
# Final case is D == 0, a single eigenvalue. If the eigenspace is 2-dimensional
# then we have a scalar matrix, deal with this case first.
scalar_matrix = And(Eq(a, d), Eq(b, 0), Eq(c, 0))
vector1 = Matrix((S.One, S.Zero))
vector2 = Matrix((S.Zero, S.One))
sol_vector = exp(l1*t) * (C1*vector1 + C2*vector2)
gsol1.append((sol_vector[0], scalar_matrix))
gsol2.append((sol_vector[1], scalar_matrix))
# Have one eigenvector. Get a generalized eigenvector from (A-lam)*vector2 = vector1
vector1 = Matrix((Piecewise((l1 - d, bad_ab_vector1), (b, True)),
Piecewise((c, bad_ab_vector1), (l1 - a, True))))
vector2 = Matrix((Piecewise((S.One, bad_ab_vector1), (S.Zero, Eq(a, l1)),
(b/(a - l1), True)),
Piecewise((S.Zero, bad_ab_vector1), (S.One, Eq(a, l1)),
(S.Zero, True))))
sol_vector = exp(l1*t) * (C1*vector1 + C2*(vector2 + t*vector1))
gsol1.append((sol_vector[0], equal_roots))
gsol2.append((sol_vector[1], equal_roots))
return [Eq(x(t), Piecewise(*gsol1)), Eq(y(t), Piecewise(*gsol2))]
def _linear_2eq_order1_type2(x, y, t, r, eq):
r"""
The equations of this type are
.. math:: x' = ax + by + k1 , y' = cx + dy + k2
The general solution of this system is given by sum of its particular solution and the
general solution of the corresponding homogeneous system is obtained from type1.
1. When `ad - bc \neq 0`. The particular solution will be
`x = x_0` and `y = y_0` where `x_0` and `y_0` are determined by solving linear system of equations
.. math:: a x_0 + b y_0 + k1 = 0 , c x_0 + d y_0 + k2 = 0
2. When `ad - bc = 0` and `a^{2} + b^{2} > 0`. In this case, the system of equation becomes
.. math:: x' = ax + by + k_1 , y' = k (ax + by) + k_2
2.1 If `\sigma = a + bk \neq 0`, particular solution is given by
.. math:: x = b \sigma^{-1} (c_1 k - c_2) t - \sigma^{-2} (a c_1 + b c_2)
.. math:: y = kx + (c_2 - c_1 k) t
2.2 If `\sigma = a + bk = 0`, particular solution is given by
.. math:: x = \frac{1}{2} b (c_2 - c_1 k) t^{2} + c_1 t
.. math:: y = kx + (c_2 - c_1 k) t
"""
r['k1'] = -r['k1']; r['k2'] = -r['k2']
if (r['a']*r['d'] - r['b']*r['c']) != 0:
x0, y0 = symbols('x0, y0', cls=Dummy)
sol = solve((r['a']*x0+r['b']*y0+r['k1'], r['c']*x0+r['d']*y0+r['k2']), x0, y0)
psol = [sol[x0], sol[y0]]
elif (r['a']*r['d'] - r['b']*r['c']) == 0 and (r['a']**2+r['b']**2) > 0:
k = r['c']/r['a']
sigma = r['a'] + r['b']*k
if sigma != 0:
sol1 = r['b']*sigma**-1*(r['k1']*k-r['k2'])*t - sigma**-2*(r['a']*r['k1']+r['b']*r['k2'])
sol2 = k*sol1 + (r['k2']-r['k1']*k)*t
else:
# FIXME: a previous typo fix shows this is not covered by tests
sol1 = r['b']*(r['k2']-r['k1']*k)*t**2 + r['k1']*t
sol2 = k*sol1 + (r['k2']-r['k1']*k)*t
psol = [sol1, sol2]
return psol
def _linear_2eq_order1_type3(x, y, t, r, eq):
r"""
The equations of this type of ode are
.. math:: x' = f(t) x + g(t) y
.. math:: y' = g(t) x + f(t) y
The solution of such equations is given by
.. math:: x = e^{F} (C_1 e^{G} + C_2 e^{-G}) , y = e^{F} (C_1 e^{G} - C_2 e^{-G})
where `C_1` and `C_2` are arbitrary constants, and
.. math:: F = \int f(t) \,dt , G = \int g(t) \,dt
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
F = Integral(r['a'], t)
G = Integral(r['b'], t)
sol1 = exp(F)*(C1*exp(G) + C2*exp(-G))
sol2 = exp(F)*(C1*exp(G) - C2*exp(-G))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order1_type4(x, y, t, r, eq):
r"""
The equations of this type of ode are .
.. math:: x' = f(t) x + g(t) y
.. math:: y' = -g(t) x + f(t) y
The solution is given by
.. math:: x = F (C_1 \cos(G) + C_2 \sin(G)), y = F (-C_1 \sin(G) + C_2 \cos(G))
where `C_1` and `C_2` are arbitrary constants, and
.. math:: F = \int f(t) \,dt , G = \int g(t) \,dt
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
if r['b'] == -r['c']:
F = exp(Integral(r['a'], t))
G = Integral(r['b'], t)
sol1 = F*(C1*cos(G) + C2*sin(G))
sol2 = F*(-C1*sin(G) + C2*cos(G))
elif r['d'] == -r['a']:
F = exp(Integral(r['c'], t))
G = Integral(r['d'], t)
sol1 = F*(-C1*sin(G) + C2*cos(G))
sol2 = F*(C1*cos(G) + C2*sin(G))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order1_type5(x, y, t, r, eq):
r"""
The equations of this type of ode are .
.. math:: x' = f(t) x + g(t) y
.. math:: y' = a g(t) x + [f(t) + b g(t)] y
The transformation of
.. math:: x = e^{\int f(t) \,dt} u , y = e^{\int f(t) \,dt} v , T = \int g(t) \,dt
leads to a system of constant coefficient linear differential equations
.. math:: u'(T) = v , v'(T) = au + bv
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
u, v = symbols('u, v', cls=Function)
T = Symbol('T')
if not cancel(r['c']/r['b']).has(t):
p = cancel(r['c']/r['b'])
q = cancel((r['d']-r['a'])/r['b'])
eq = (Eq(diff(u(T),T), v(T)), Eq(diff(v(T),T), p*u(T)+q*v(T)))
sol = dsolve(eq)
sol1 = exp(Integral(r['a'], t))*sol[0].rhs.subs(T, Integral(r['b'],t))
sol2 = exp(Integral(r['a'], t))*sol[1].rhs.subs(T, Integral(r['b'],t))
if not cancel(r['a']/r['d']).has(t):
p = cancel(r['a']/r['d'])
q = cancel((r['b']-r['c'])/r['d'])
sol = dsolve(Eq(diff(u(T),T), v(T)), Eq(diff(v(T),T), p*u(T)+q*v(T)))
sol1 = exp(Integral(r['c'], t))*sol[1].rhs.subs(T, Integral(r['d'],t))
sol2 = exp(Integral(r['c'], t))*sol[0].rhs.subs(T, Integral(r['d'],t))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order1_type6(x, y, t, r, eq):
r"""
The equations of this type of ode are .
.. math:: x' = f(t) x + g(t) y
.. math:: y' = a [f(t) + a h(t)] x + a [g(t) - h(t)] y
This is solved by first multiplying the first equation by `-a` and adding
it to the second equation to obtain
.. math:: y' - a x' = -a h(t) (y - a x)
Setting `U = y - ax` and integrating the equation we arrive at
.. math:: y - ax = C_1 e^{-a \int h(t) \,dt}
and on substituting the value of y in first equation give rise to first order ODEs. After solving for
`x`, we can obtain `y` by substituting the value of `x` in second equation.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
p = 0
q = 0
p1 = cancel(r['c']/cancel(r['c']/r['d']).as_numer_denom()[0])
p2 = cancel(r['a']/cancel(r['a']/r['b']).as_numer_denom()[0])
for n, i in enumerate([p1, p2]):
for j in Mul.make_args(collect_const(i)):
if not j.has(t):
q = j
if q!=0 and n==0:
if ((r['c']/j - r['a'])/(r['b'] - r['d']/j)) == j:
p = 1
s = j
break
if q!=0 and n==1:
if ((r['a']/j - r['c'])/(r['d'] - r['b']/j)) == j:
p = 2
s = j
break
if p == 1:
equ = diff(x(t),t) - r['a']*x(t) - r['b']*(s*x(t) + C1*exp(-s*Integral(r['b'] - r['d']/s, t)))
hint1 = classify_ode(equ)[1]
sol1 = dsolve(equ, hint=hint1+'_Integral').rhs
sol2 = s*sol1 + C1*exp(-s*Integral(r['b'] - r['d']/s, t))
elif p ==2:
equ = diff(y(t),t) - r['c']*y(t) - r['d']*s*y(t) + C1*exp(-s*Integral(r['d'] - r['b']/s, t))
hint1 = classify_ode(equ)[1]
sol2 = dsolve(equ, hint=hint1+'_Integral').rhs
sol1 = s*sol2 + C1*exp(-s*Integral(r['d'] - r['b']/s, t))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order1_type7(x, y, t, r, eq):
r"""
The equations of this type of ode are .
.. math:: x' = f(t) x + g(t) y
.. math:: y' = h(t) x + p(t) y
Differentiating the first equation and substituting the value of `y`
from second equation will give a second-order linear equation
.. math:: g x'' - (fg + gp + g') x' + (fgp - g^{2} h + f g' - f' g) x = 0
This above equation can be easily integrated if following conditions are satisfied.
1. `fgp - g^{2} h + f g' - f' g = 0`
2. `fgp - g^{2} h + f g' - f' g = ag, fg + gp + g' = bg`
If first condition is satisfied then it is solved by current dsolve solver and in second case it becomes
a constant coefficient differential equation which is also solved by current solver.
Otherwise if the above condition fails then,
a particular solution is assumed as `x = x_0(t)` and `y = y_0(t)`
Then the general solution is expressed as
.. math:: x = C_1 x_0(t) + C_2 x_0(t) \int \frac{g(t) F(t) P(t)}{x_0^{2}(t)} \,dt
.. math:: y = C_1 y_0(t) + C_2 [\frac{F(t) P(t)}{x_0(t)} + y_0(t) \int \frac{g(t) F(t) P(t)}{x_0^{2}(t)} \,dt]
where C1 and C2 are arbitrary constants and
.. math:: F(t) = e^{\int f(t) \,dt} , P(t) = e^{\int p(t) \,dt}
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
e1 = r['a']*r['b']*r['c'] - r['b']**2*r['c'] + r['a']*diff(r['b'],t) - diff(r['a'],t)*r['b']
e2 = r['a']*r['c']*r['d'] - r['b']*r['c']**2 + diff(r['c'],t)*r['d'] - r['c']*diff(r['d'],t)
m1 = r['a']*r['b'] + r['b']*r['d'] + diff(r['b'],t)
m2 = r['a']*r['c'] + r['c']*r['d'] + diff(r['c'],t)
if e1 == 0:
sol1 = dsolve(r['b']*diff(x(t),t,t) - m1*diff(x(t),t)).rhs
sol2 = dsolve(diff(y(t),t) - r['c']*sol1 - r['d']*y(t)).rhs
elif e2 == 0:
sol2 = dsolve(r['c']*diff(y(t),t,t) - m2*diff(y(t),t)).rhs
sol1 = dsolve(diff(x(t),t) - r['a']*x(t) - r['b']*sol2).rhs
elif not (e1/r['b']).has(t) and not (m1/r['b']).has(t):
sol1 = dsolve(diff(x(t),t,t) - (m1/r['b'])*diff(x(t),t) - (e1/r['b'])*x(t)).rhs
sol2 = dsolve(diff(y(t),t) - r['c']*sol1 - r['d']*y(t)).rhs
elif not (e2/r['c']).has(t) and not (m2/r['c']).has(t):
sol2 = dsolve(diff(y(t),t,t) - (m2/r['c'])*diff(y(t),t) - (e2/r['c'])*y(t)).rhs
sol1 = dsolve(diff(x(t),t) - r['a']*x(t) - r['b']*sol2).rhs
else:
x0 = Function('x0')(t) # x0 and y0 being particular solutions
y0 = Function('y0')(t)
F = exp(Integral(r['a'],t))
P = exp(Integral(r['d'],t))
sol1 = C1*x0 + C2*x0*Integral(r['b']*F*P/x0**2, t)
sol2 = C1*y0 + C2*(F*P/x0 + y0*Integral(r['b']*F*P/x0**2, t))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def sysode_linear_2eq_order2(match_):
x = match_['func'][0].func
y = match_['func'][1].func
func = match_['func']
fc = match_['func_coeff']
eq = match_['eq']
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
r = dict()
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
for i in range(2):
eqs = []
for terms in Add.make_args(eq[i]):
eqs.append(terms/fc[i,func[i],2])
eq[i] = Add(*eqs)
# for equations Eq(diff(x(t),t,t), a1*diff(x(t),t)+b1*diff(y(t),t)+c1*x(t)+d1*y(t)+e1)
# and Eq(a2*diff(y(t),t,t), a2*diff(x(t),t)+b2*diff(y(t),t)+c2*x(t)+d2*y(t)+e2)
r['a1'] = -fc[0,x(t),1]/fc[0,x(t),2] ; r['a2'] = -fc[1,x(t),1]/fc[1,y(t),2]
r['b1'] = -fc[0,y(t),1]/fc[0,x(t),2] ; r['b2'] = -fc[1,y(t),1]/fc[1,y(t),2]
r['c1'] = -fc[0,x(t),0]/fc[0,x(t),2] ; r['c2'] = -fc[1,x(t),0]/fc[1,y(t),2]
r['d1'] = -fc[0,y(t),0]/fc[0,x(t),2] ; r['d2'] = -fc[1,y(t),0]/fc[1,y(t),2]
const = [S(0), S(0)]
for i in range(2):
for j in Add.make_args(eq[i]):
if not (j.has(x(t)) or j.has(y(t))):
const[i] += j
r['e1'] = -const[0]
r['e2'] = -const[1]
if match_['type_of_equation'] == 'type1':
sol = _linear_2eq_order2_type1(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type2':
gsol = _linear_2eq_order2_type1(x, y, t, r, eq)
psol = _linear_2eq_order2_type2(x, y, t, r, eq)
sol = [Eq(x(t), gsol[0].rhs+psol[0]), Eq(y(t), gsol[1].rhs+psol[1])]
elif match_['type_of_equation'] == 'type3':
sol = _linear_2eq_order2_type3(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type4':
sol = _linear_2eq_order2_type4(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type5':
sol = _linear_2eq_order2_type5(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type6':
sol = _linear_2eq_order2_type6(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type7':
sol = _linear_2eq_order2_type7(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type8':
sol = _linear_2eq_order2_type8(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type9':
sol = _linear_2eq_order2_type9(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type10':
sol = _linear_2eq_order2_type10(x, y, t, r, eq)
elif match_['type_of_equation'] == 'type11':
sol = _linear_2eq_order2_type11(x, y, t, r, eq)
return sol
def _linear_2eq_order2_type1(x, y, t, r, eq):
r"""
System of two constant-coefficient second-order linear homogeneous differential equations
.. math:: x'' = ax + by
.. math:: y'' = cx + dy
The characteristic equation for above equations
.. math:: \lambda^4 - (a + d) \lambda^2 + ad - bc = 0
whose discriminant is `D = (a - d)^2 + 4bc \neq 0`
1. When `ad - bc \neq 0`
1.1. If `D \neq 0`. The characteristic equation has four distinct roots, `\lambda_1, \lambda_2, \lambda_3, \lambda_4`.
The general solution of the system is
.. math:: x = C_1 b e^{\lambda_1 t} + C_2 b e^{\lambda_2 t} + C_3 b e^{\lambda_3 t} + C_4 b e^{\lambda_4 t}
.. math:: y = C_1 (\lambda_1^{2} - a) e^{\lambda_1 t} + C_2 (\lambda_2^{2} - a) e^{\lambda_2 t} + C_3 (\lambda_3^{2} - a) e^{\lambda_3 t} + C_4 (\lambda_4^{2} - a) e^{\lambda_4 t}
where `C_1,..., C_4` are arbitrary constants.
1.2. If `D = 0` and `a \neq d`:
.. math:: x = 2 C_1 (bt + \frac{2bk}{a - d}) e^{\frac{kt}{2}} + 2 C_2 (bt + \frac{2bk}{a - d}) e^{\frac{-kt}{2}} + 2b C_3 t e^{\frac{kt}{2}} + 2b C_4 t e^{\frac{-kt}{2}}
.. math:: y = C_1 (d - a) t e^{\frac{kt}{2}} + C_2 (d - a) t e^{\frac{-kt}{2}} + C_3 [(d - a) t + 2k] e^{\frac{kt}{2}} + C_4 [(d - a) t - 2k] e^{\frac{-kt}{2}}
where `C_1,..., C_4` are arbitrary constants and `k = \sqrt{2 (a + d)}`
1.3. If `D = 0` and `a = d \neq 0` and `b = 0`:
.. math:: x = 2 \sqrt{a} C_1 e^{\sqrt{a} t} + 2 \sqrt{a} C_2 e^{-\sqrt{a} t}
.. math:: y = c C_1 t e^{\sqrt{a} t} - c C_2 t e^{-\sqrt{a} t} + C_3 e^{\sqrt{a} t} + C_4 e^{-\sqrt{a} t}
1.4. If `D = 0` and `a = d \neq 0` and `c = 0`:
.. math:: x = b C_1 t e^{\sqrt{a} t} - b C_2 t e^{-\sqrt{a} t} + C_3 e^{\sqrt{a} t} + C_4 e^{-\sqrt{a} t}
.. math:: y = 2 \sqrt{a} C_1 e^{\sqrt{a} t} + 2 \sqrt{a} C_2 e^{-\sqrt{a} t}
2. When `ad - bc = 0` and `a^2 + b^2 > 0`. Then the original system becomes
.. math:: x'' = ax + by
.. math:: y'' = k (ax + by)
2.1. If `a + bk \neq 0`:
.. math:: x = C_1 e^{t \sqrt{a + bk}} + C_2 e^{-t \sqrt{a + bk}} + C_3 bt + C_4 b
.. math:: y = C_1 k e^{t \sqrt{a + bk}} + C_2 k e^{-t \sqrt{a + bk}} - C_3 at - C_4 a
2.2. If `a + bk = 0`:
.. math:: x = C_1 b t^3 + C_2 b t^2 + C_3 t + C_4
.. math:: y = kx + 6 C_1 t + 2 C_2
"""
r['a'] = r['c1']
r['b'] = r['d1']
r['c'] = r['c2']
r['d'] = r['d2']
l = Symbol('l')
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
chara_eq = l**4 - (r['a']+r['d'])*l**2 + r['a']*r['d'] - r['b']*r['c']
l1 = rootof(chara_eq, 0)
l2 = rootof(chara_eq, 1)
l3 = rootof(chara_eq, 2)
l4 = rootof(chara_eq, 3)
D = (r['a'] - r['d'])**2 + 4*r['b']*r['c']
if (r['a']*r['d'] - r['b']*r['c']) != 0:
if D != 0:
gsol1 = C1*r['b']*exp(l1*t) + C2*r['b']*exp(l2*t) + C3*r['b']*exp(l3*t) \
+ C4*r['b']*exp(l4*t)
gsol2 = C1*(l1**2-r['a'])*exp(l1*t) + C2*(l2**2-r['a'])*exp(l2*t) + \
C3*(l3**2-r['a'])*exp(l3*t) + C4*(l4**2-r['a'])*exp(l4*t)
else:
if r['a'] != r['d']:
k = sqrt(2*(r['a']+r['d']))
mid = r['b']*t+2*r['b']*k/(r['a']-r['d'])
gsol1 = 2*C1*mid*exp(k*t/2) + 2*C2*mid*exp(-k*t/2) + \
2*r['b']*C3*t*exp(k*t/2) + 2*r['b']*C4*t*exp(-k*t/2)
gsol2 = C1*(r['d']-r['a'])*t*exp(k*t/2) + C2*(r['d']-r['a'])*t*exp(-k*t/2) + \
C3*((r['d']-r['a'])*t+2*k)*exp(k*t/2) + C4*((r['d']-r['a'])*t-2*k)*exp(-k*t/2)
elif r['a'] == r['d'] != 0 and r['b'] == 0:
sa = sqrt(r['a'])
gsol1 = 2*sa*C1*exp(sa*t) + 2*sa*C2*exp(-sa*t)
gsol2 = r['c']*C1*t*exp(sa*t)-r['c']*C2*t*exp(-sa*t)+C3*exp(sa*t)+C4*exp(-sa*t)
elif r['a'] == r['d'] != 0 and r['c'] == 0:
sa = sqrt(r['a'])
gsol1 = r['b']*C1*t*exp(sa*t)-r['b']*C2*t*exp(-sa*t)+C3*exp(sa*t)+C4*exp(-sa*t)
gsol2 = 2*sa*C1*exp(sa*t) + 2*sa*C2*exp(-sa*t)
elif (r['a']*r['d'] - r['b']*r['c']) == 0 and (r['a']**2 + r['b']**2) > 0:
k = r['c']/r['a']
if r['a'] + r['b']*k != 0:
mid = sqrt(r['a'] + r['b']*k)
gsol1 = C1*exp(mid*t) + C2*exp(-mid*t) + C3*r['b']*t + C4*r['b']
gsol2 = C1*k*exp(mid*t) + C2*k*exp(-mid*t) - C3*r['a']*t - C4*r['a']
else:
gsol1 = C1*r['b']*t**3 + C2*r['b']*t**2 + C3*t + C4
gsol2 = k*gsol1 + 6*C1*t + 2*C2
return [Eq(x(t), gsol1), Eq(y(t), gsol2)]
def _linear_2eq_order2_type2(x, y, t, r, eq):
r"""
The equations in this type are
.. math:: x'' = a_1 x + b_1 y + c_1
.. math:: y'' = a_2 x + b_2 y + c_2
The general solution of this system is given by the sum of its particular solution
and the general solution of the homogeneous system. The general solution is given
by the linear system of 2 equation of order 2 and type 1
1. If `a_1 b_2 - a_2 b_1 \neq 0`. A particular solution will be `x = x_0` and `y = y_0`
where the constants `x_0` and `y_0` are determined by solving the linear algebraic system
.. math:: a_1 x_0 + b_1 y_0 + c_1 = 0, a_2 x_0 + b_2 y_0 + c_2 = 0
2. If `a_1 b_2 - a_2 b_1 = 0` and `a_1^2 + b_1^2 > 0`. In this case, the system in question becomes
.. math:: x'' = ax + by + c_1, y'' = k (ax + by) + c_2
2.1. If `\sigma = a + bk \neq 0`, the particular solution will be
.. math:: x = \frac{1}{2} b \sigma^{-1} (c_1 k - c_2) t^2 - \sigma^{-2} (a c_1 + b c_2)
.. math:: y = kx + \frac{1}{2} (c_2 - c_1 k) t^2
2.2. If `\sigma = a + bk = 0`, the particular solution will be
.. math:: x = \frac{1}{24} b (c_2 - c_1 k) t^4 + \frac{1}{2} c_1 t^2
.. math:: y = kx + \frac{1}{2} (c_2 - c_1 k) t^2
"""
x0, y0 = symbols('x0, y0')
if r['c1']*r['d2'] - r['c2']*r['d1'] != 0:
sol = solve((r['c1']*x0+r['d1']*y0+r['e1'], r['c2']*x0+r['d2']*y0+r['e2']), x0, y0)
psol = [sol[x0], sol[y0]]
elif r['c1']*r['d2'] - r['c2']*r['d1'] == 0 and (r['c1']**2 + r['d1']**2) > 0:
k = r['c2']/r['c1']
sig = r['c1'] + r['d1']*k
if sig != 0:
psol1 = r['d1']*sig**-1*(r['e1']*k-r['e2'])*t**2/2 - \
sig**-2*(r['c1']*r['e1']+r['d1']*r['e2'])
psol2 = k*psol1 + (r['e2'] - r['e1']*k)*t**2/2
psol = [psol1, psol2]
else:
psol1 = r['d1']*(r['e2']-r['e1']*k)*t**4/24 + r['e1']*t**2/2
psol2 = k*psol1 + (r['e2']-r['e1']*k)*t**2/2
psol = [psol1, psol2]
return psol
def _linear_2eq_order2_type3(x, y, t, r, eq):
r"""
These type of equation is used for describing the horizontal motion of a pendulum
taking into account the Earth rotation.
The solution is given with `a^2 + 4b > 0`:
.. math:: x = C_1 \cos(\alpha t) + C_2 \sin(\alpha t) + C_3 \cos(\beta t) + C_4 \sin(\beta t)
.. math:: y = -C_1 \sin(\alpha t) + C_2 \cos(\alpha t) - C_3 \sin(\beta t) + C_4 \cos(\beta t)
where `C_1,...,C_4` and
.. math:: \alpha = \frac{1}{2} a + \frac{1}{2} \sqrt{a^2 + 4b}, \beta = \frac{1}{2} a - \frac{1}{2} \sqrt{a^2 + 4b}
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
if r['b1']**2 - 4*r['c1'] > 0:
r['a'] = r['b1'] ; r['b'] = -r['c1']
alpha = r['a']/2 + sqrt(r['a']**2 + 4*r['b'])/2
beta = r['a']/2 - sqrt(r['a']**2 + 4*r['b'])/2
sol1 = C1*cos(alpha*t) + C2*sin(alpha*t) + C3*cos(beta*t) + C4*sin(beta*t)
sol2 = -C1*sin(alpha*t) + C2*cos(alpha*t) - C3*sin(beta*t) + C4*cos(beta*t)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type4(x, y, t, r, eq):
r"""
These equations are found in the theory of oscillations
.. math:: x'' + a_1 x' + b_1 y' + c_1 x + d_1 y = k_1 e^{i \omega t}
.. math:: y'' + a_2 x' + b_2 y' + c_2 x + d_2 y = k_2 e^{i \omega t}
The general solution of this linear nonhomogeneous system of constant-coefficient
differential equations is given by the sum of its particular solution and the
general solution of the corresponding homogeneous system (with `k_1 = k_2 = 0`)
1. A particular solution is obtained by the method of undetermined coefficients:
.. math:: x = A_* e^{i \omega t}, y = B_* e^{i \omega t}
On substituting these expressions into the original system of differential equations,
one arrive at a linear nonhomogeneous system of algebraic equations for the
coefficients `A` and `B`.
2. The general solution of the homogeneous system of differential equations is determined
by a linear combination of linearly independent particular solutions determined by
the method of undetermined coefficients in the form of exponentials:
.. math:: x = A e^{\lambda t}, y = B e^{\lambda t}
On substituting these expressions into the original system and collecting the
coefficients of the unknown `A` and `B`, one obtains
.. math:: (\lambda^{2} + a_1 \lambda + c_1) A + (b_1 \lambda + d_1) B = 0
.. math:: (a_2 \lambda + c_2) A + (\lambda^{2} + b_2 \lambda + d_2) B = 0
The determinant of this system must vanish for nontrivial solutions A, B to exist.
This requirement results in the following characteristic equation for `\lambda`
.. math:: (\lambda^2 + a_1 \lambda + c_1) (\lambda^2 + b_2 \lambda + d_2) - (b_1 \lambda + d_1) (a_2 \lambda + c_2) = 0
If all roots `k_1,...,k_4` of this equation are distinct, the general solution of the original
system of the differential equations has the form
.. math:: x = C_1 (b_1 \lambda_1 + d_1) e^{\lambda_1 t} - C_2 (b_1 \lambda_2 + d_1) e^{\lambda_2 t} - C_3 (b_1 \lambda_3 + d_1) e^{\lambda_3 t} - C_4 (b_1 \lambda_4 + d_1) e^{\lambda_4 t}
.. math:: y = C_1 (\lambda_1^{2} + a_1 \lambda_1 + c_1) e^{\lambda_1 t} + C_2 (\lambda_2^{2} + a_1 \lambda_2 + c_1) e^{\lambda_2 t} + C_3 (\lambda_3^{2} + a_1 \lambda_3 + c_1) e^{\lambda_3 t} + C_4 (\lambda_4^{2} + a_1 \lambda_4 + c_1) e^{\lambda_4 t}
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
k = Symbol('k')
Ra, Ca, Rb, Cb = symbols('Ra, Ca, Rb, Cb')
a1 = r['a1'] ; a2 = r['a2']
b1 = r['b1'] ; b2 = r['b2']
c1 = r['c1'] ; c2 = r['c2']
d1 = r['d1'] ; d2 = r['d2']
k1 = r['e1'].expand().as_independent(t)[0]
k2 = r['e2'].expand().as_independent(t)[0]
ew1 = r['e1'].expand().as_independent(t)[1]
ew2 = powdenest(ew1).as_base_exp()[1]
ew3 = collect(ew2, t).coeff(t)
w = cancel(ew3/I)
# The particular solution is assumed to be (Ra+I*Ca)*exp(I*w*t) and
# (Rb+I*Cb)*exp(I*w*t) for x(t) and y(t) respectively
peq1 = (-w**2+c1)*Ra - a1*w*Ca + d1*Rb - b1*w*Cb - k1
peq2 = a1*w*Ra + (-w**2+c1)*Ca + b1*w*Rb + d1*Cb
peq3 = c2*Ra - a2*w*Ca + (-w**2+d2)*Rb - b2*w*Cb - k2
peq4 = a2*w*Ra + c2*Ca + b2*w*Rb + (-w**2+d2)*Cb
# FIXME: solve for what in what? Ra, Rb, etc I guess
# but then psol not used for anything?
psol = solve([peq1, peq2, peq3, peq4])
chareq = (k**2+a1*k+c1)*(k**2+b2*k+d2) - (b1*k+d1)*(a2*k+c2)
[k1, k2, k3, k4] = roots_quartic(Poly(chareq))
sol1 = -C1*(b1*k1+d1)*exp(k1*t) - C2*(b1*k2+d1)*exp(k2*t) - \
C3*(b1*k3+d1)*exp(k3*t) - C4*(b1*k4+d1)*exp(k4*t) + (Ra+I*Ca)*exp(I*w*t)
a1_ = (a1-1)
sol2 = C1*(k1**2+a1_*k1+c1)*exp(k1*t) + C2*(k2**2+a1_*k2+c1)*exp(k2*t) + \
C3*(k3**2+a1_*k3+c1)*exp(k3*t) + C4*(k4**2+a1_*k4+c1)*exp(k4*t) + (Rb+I*Cb)*exp(I*w*t)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type5(x, y, t, r, eq):
r"""
The equation which come under this category are
.. math:: x'' = a (t y' - y)
.. math:: y'' = b (t x' - x)
The transformation
.. math:: u = t x' - x, b = t y' - y
leads to the first-order system
.. math:: u' = atv, v' = btu
The general solution of this system is given by
If `ab > 0`:
.. math:: u = C_1 a e^{\frac{1}{2} \sqrt{ab} t^2} + C_2 a e^{-\frac{1}{2} \sqrt{ab} t^2}
.. math:: v = C_1 \sqrt{ab} e^{\frac{1}{2} \sqrt{ab} t^2} - C_2 \sqrt{ab} e^{-\frac{1}{2} \sqrt{ab} t^2}
If `ab < 0`:
.. math:: u = C_1 a \cos(\frac{1}{2} \sqrt{\left|ab\right|} t^2) + C_2 a \sin(-\frac{1}{2} \sqrt{\left|ab\right|} t^2)
.. math:: v = C_1 \sqrt{\left|ab\right|} \sin(\frac{1}{2} \sqrt{\left|ab\right|} t^2) + C_2 \sqrt{\left|ab\right|} \cos(-\frac{1}{2} \sqrt{\left|ab\right|} t^2)
where `C_1` and `C_2` are arbitrary constants. On substituting the value of `u` and `v`
in above equations and integrating the resulting expressions, the general solution will become
.. math:: x = C_3 t + t \int \frac{u}{t^2} \,dt, y = C_4 t + t \int \frac{u}{t^2} \,dt
where `C_3` and `C_4` are arbitrary constants.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
r['a'] = -r['d1'] ; r['b'] = -r['c2']
mul = sqrt(abs(r['a']*r['b']))
if r['a']*r['b'] > 0:
u = C1*r['a']*exp(mul*t**2/2) + C2*r['a']*exp(-mul*t**2/2)
v = C1*mul*exp(mul*t**2/2) - C2*mul*exp(-mul*t**2/2)
else:
u = C1*r['a']*cos(mul*t**2/2) + C2*r['a']*sin(mul*t**2/2)
v = -C1*mul*sin(mul*t**2/2) + C2*mul*cos(mul*t**2/2)
sol1 = C3*t + t*Integral(u/t**2, t)
sol2 = C4*t + t*Integral(v/t**2, t)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type6(x, y, t, r, eq):
r"""
The equations are
.. math:: x'' = f(t) (a_1 x + b_1 y)
.. math:: y'' = f(t) (a_2 x + b_2 y)
If `k_1` and `k_2` are roots of the quadratic equation
.. math:: k^2 - (a_1 + b_2) k + a_1 b_2 - a_2 b_1 = 0
Then by multiplying appropriate constants and adding together original equations
we obtain two independent equations:
.. math:: z_1'' = k_1 f(t) z_1, z_1 = a_2 x + (k_1 - a_1) y
.. math:: z_2'' = k_2 f(t) z_2, z_2 = a_2 x + (k_2 - a_1) y
Solving the equations will give the values of `x` and `y` after obtaining the value
of `z_1` and `z_2` by solving the differential equation and substituting the result.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
k = Symbol('k')
z = Function('z')
num, den = cancel(
(r['c1']*x(t) + r['d1']*y(t))/
(r['c2']*x(t) + r['d2']*y(t))).as_numer_denom()
f = r['c1']/num.coeff(x(t))
a1 = num.coeff(x(t))
b1 = num.coeff(y(t))
a2 = den.coeff(x(t))
b2 = den.coeff(y(t))
chareq = k**2 - (a1 + b2)*k + a1*b2 - a2*b1
k1, k2 = [rootof(chareq, k) for k in range(Poly(chareq).degree())]
z1 = dsolve(diff(z(t),t,t) - k1*f*z(t)).rhs
z2 = dsolve(diff(z(t),t,t) - k2*f*z(t)).rhs
sol1 = (k1*z2 - k2*z1 + a1*(z1 - z2))/(a2*(k1-k2))
sol2 = (z1 - z2)/(k1 - k2)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type7(x, y, t, r, eq):
r"""
The equations are given as
.. math:: x'' = f(t) (a_1 x' + b_1 y')
.. math:: y'' = f(t) (a_2 x' + b_2 y')
If `k_1` and 'k_2` are roots of the quadratic equation
.. math:: k^2 - (a_1 + b_2) k + a_1 b_2 - a_2 b_1 = 0
Then the system can be reduced by adding together the two equations multiplied
by appropriate constants give following two independent equations:
.. math:: z_1'' = k_1 f(t) z_1', z_1 = a_2 x + (k_1 - a_1) y
.. math:: z_2'' = k_2 f(t) z_2', z_2 = a_2 x + (k_2 - a_1) y
Integrating these and returning to the original variables, one arrives at a linear
algebraic system for the unknowns `x` and `y`:
.. math:: a_2 x + (k_1 - a_1) y = C_1 \int e^{k_1 F(t)} \,dt + C_2
.. math:: a_2 x + (k_2 - a_1) y = C_3 \int e^{k_2 F(t)} \,dt + C_4
where `C_1,...,C_4` are arbitrary constants and `F(t) = \int f(t) \,dt`
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
k = Symbol('k')
num, den = cancel(
(r['a1']*x(t) + r['b1']*y(t))/
(r['a2']*x(t) + r['b2']*y(t))).as_numer_denom()
f = r['a1']/num.coeff(x(t))
a1 = num.coeff(x(t))
b1 = num.coeff(y(t))
a2 = den.coeff(x(t))
b2 = den.coeff(y(t))
chareq = k**2 - (a1 + b2)*k + a1*b2 - a2*b1
[k1, k2] = [rootof(chareq, k) for k in range(Poly(chareq).degree())]
F = Integral(f, t)
z1 = C1*Integral(exp(k1*F), t) + C2
z2 = C3*Integral(exp(k2*F), t) + C4
sol1 = (k1*z2 - k2*z1 + a1*(z1 - z2))/(a2*(k1-k2))
sol2 = (z1 - z2)/(k1 - k2)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type8(x, y, t, r, eq):
r"""
The equation of this category are
.. math:: x'' = a f(t) (t y' - y)
.. math:: y'' = b f(t) (t x' - x)
The transformation
.. math:: u = t x' - x, v = t y' - y
leads to the system of first-order equations
.. math:: u' = a t f(t) v, v' = b t f(t) u
The general solution of this system has the form
If `ab > 0`:
.. math:: u = C_1 a e^{\sqrt{ab} \int t f(t) \,dt} + C_2 a e^{-\sqrt{ab} \int t f(t) \,dt}
.. math:: v = C_1 \sqrt{ab} e^{\sqrt{ab} \int t f(t) \,dt} - C_2 \sqrt{ab} e^{-\sqrt{ab} \int t f(t) \,dt}
If `ab < 0`:
.. math:: u = C_1 a \cos(\sqrt{\left|ab\right|} \int t f(t) \,dt) + C_2 a \sin(-\sqrt{\left|ab\right|} \int t f(t) \,dt)
.. math:: v = C_1 \sqrt{\left|ab\right|} \sin(\sqrt{\left|ab\right|} \int t f(t) \,dt) + C_2 \sqrt{\left|ab\right|} \cos(-\sqrt{\left|ab\right|} \int t f(t) \,dt)
where `C_1` and `C_2` are arbitrary constants. On substituting the value of `u` and `v`
in above equations and integrating the resulting expressions, the general solution will become
.. math:: x = C_3 t + t \int \frac{u}{t^2} \,dt, y = C_4 t + t \int \frac{u}{t^2} \,dt
where `C_3` and `C_4` are arbitrary constants.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
num, den = cancel(r['d1']/r['c2']).as_numer_denom()
f = -r['d1']/num
a = num
b = den
mul = sqrt(abs(a*b))
Igral = Integral(t*f, t)
if a*b > 0:
u = C1*a*exp(mul*Igral) + C2*a*exp(-mul*Igral)
v = C1*mul*exp(mul*Igral) - C2*mul*exp(-mul*Igral)
else:
u = C1*a*cos(mul*Igral) + C2*a*sin(mul*Igral)
v = -C1*mul*sin(mul*Igral) + C2*mul*cos(mul*Igral)
sol1 = C3*t + t*Integral(u/t**2, t)
sol2 = C4*t + t*Integral(v/t**2, t)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type9(x, y, t, r, eq):
r"""
.. math:: t^2 x'' + a_1 t x' + b_1 t y' + c_1 x + d_1 y = 0
.. math:: t^2 y'' + a_2 t x' + b_2 t y' + c_2 x + d_2 y = 0
These system of equations are euler type.
The substitution of `t = \sigma e^{\tau} (\sigma \neq 0)` leads to the system of constant
coefficient linear differential equations
.. math:: x'' + (a_1 - 1) x' + b_1 y' + c_1 x + d_1 y = 0
.. math:: y'' + a_2 x' + (b_2 - 1) y' + c_2 x + d_2 y = 0
The general solution of the homogeneous system of differential equations is determined
by a linear combination of linearly independent particular solutions determined by
the method of undetermined coefficients in the form of exponentials
.. math:: x = A e^{\lambda t}, y = B e^{\lambda t}
On substituting these expressions into the original system and collecting the
coefficients of the unknown `A` and `B`, one obtains
.. math:: (\lambda^{2} + (a_1 - 1) \lambda + c_1) A + (b_1 \lambda + d_1) B = 0
.. math:: (a_2 \lambda + c_2) A + (\lambda^{2} + (b_2 - 1) \lambda + d_2) B = 0
The determinant of this system must vanish for nontrivial solutions A, B to exist.
This requirement results in the following characteristic equation for `\lambda`
.. math:: (\lambda^2 + (a_1 - 1) \lambda + c_1) (\lambda^2 + (b_2 - 1) \lambda + d_2) - (b_1 \lambda + d_1) (a_2 \lambda + c_2) = 0
If all roots `k_1,...,k_4` of this equation are distinct, the general solution of the original
system of the differential equations has the form
.. math:: x = C_1 (b_1 \lambda_1 + d_1) e^{\lambda_1 t} - C_2 (b_1 \lambda_2 + d_1) e^{\lambda_2 t} - C_3 (b_1 \lambda_3 + d_1) e^{\lambda_3 t} - C_4 (b_1 \lambda_4 + d_1) e^{\lambda_4 t}
.. math:: y = C_1 (\lambda_1^{2} + (a_1 - 1) \lambda_1 + c_1) e^{\lambda_1 t} + C_2 (\lambda_2^{2} + (a_1 - 1) \lambda_2 + c_1) e^{\lambda_2 t} + C_3 (\lambda_3^{2} + (a_1 - 1) \lambda_3 + c_1) e^{\lambda_3 t} + C_4 (\lambda_4^{2} + (a_1 - 1) \lambda_4 + c_1) e^{\lambda_4 t}
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
k = Symbol('k')
a1 = -r['a1']*t; a2 = -r['a2']*t
b1 = -r['b1']*t; b2 = -r['b2']*t
c1 = -r['c1']*t**2; c2 = -r['c2']*t**2
d1 = -r['d1']*t**2; d2 = -r['d2']*t**2
eq = (k**2+(a1-1)*k+c1)*(k**2+(b2-1)*k+d2)-(b1*k+d1)*(a2*k+c2)
[k1, k2, k3, k4] = roots_quartic(Poly(eq))
sol1 = -C1*(b1*k1+d1)*exp(k1*log(t)) - C2*(b1*k2+d1)*exp(k2*log(t)) - \
C3*(b1*k3+d1)*exp(k3*log(t)) - C4*(b1*k4+d1)*exp(k4*log(t))
a1_ = (a1-1)
sol2 = C1*(k1**2+a1_*k1+c1)*exp(k1*log(t)) + C2*(k2**2+a1_*k2+c1)*exp(k2*log(t)) \
+ C3*(k3**2+a1_*k3+c1)*exp(k3*log(t)) + C4*(k4**2+a1_*k4+c1)*exp(k4*log(t))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type10(x, y, t, r, eq):
r"""
The equation of this category are
.. math:: (\alpha t^2 + \beta t + \gamma)^{2} x'' = ax + by
.. math:: (\alpha t^2 + \beta t + \gamma)^{2} y'' = cx + dy
The transformation
.. math:: \tau = \int \frac{1}{\alpha t^2 + \beta t + \gamma} \,dt , u = \frac{x}{\sqrt{\left|\alpha t^2 + \beta t + \gamma\right|}} , v = \frac{y}{\sqrt{\left|\alpha t^2 + \beta t + \gamma\right|}}
leads to a constant coefficient linear system of equations
.. math:: u'' = (a - \alpha \gamma + \frac{1}{4} \beta^{2}) u + b v
.. math:: v'' = c u + (d - \alpha \gamma + \frac{1}{4} \beta^{2}) v
These system of equations obtained can be solved by type1 of System of two
constant-coefficient second-order linear homogeneous differential equations.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
u, v = symbols('u, v', cls=Function)
assert False
T = Symbol('T')
p = Wild('p', exclude=[t, t**2])
q = Wild('q', exclude=[t, t**2])
s = Wild('s', exclude=[t, t**2])
n = Wild('n', exclude=[t, t**2])
num, den = r['c1'].as_numer_denom()
dic = den.match((n*(p*t**2+q*t+s)**2).expand())
eqz = dic[p]*t**2 + dic[q]*t + dic[s]
a = num/dic[n]
b = cancel(r['d1']*eqz**2)
c = cancel(r['c2']*eqz**2)
d = cancel(r['d2']*eqz**2)
[msol1, msol2] = dsolve([Eq(diff(u(t), t, t), (a - dic[p]*dic[s] + dic[q]**2/4)*u(t) \
+ b*v(t)), Eq(diff(v(t),t,t), c*u(t) + (d - dic[p]*dic[s] + dic[q]**2/4)*v(t))])
sol1 = (msol1.rhs*sqrt(abs(eqz))).subs(t, Integral(1/eqz, t))
sol2 = (msol2.rhs*sqrt(abs(eqz))).subs(t, Integral(1/eqz, t))
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def _linear_2eq_order2_type11(x, y, t, r, eq):
r"""
The equations which comes under this type are
.. math:: x'' = f(t) (t x' - x) + g(t) (t y' - y)
.. math:: y'' = h(t) (t x' - x) + p(t) (t y' - y)
The transformation
.. math:: u = t x' - x, v = t y' - y
leads to the linear system of first-order equations
.. math:: u' = t f(t) u + t g(t) v, v' = t h(t) u + t p(t) v
On substituting the value of `u` and `v` in transformed equation gives value of `x` and `y` as
.. math:: x = C_3 t + t \int \frac{u}{t^2} \,dt , y = C_4 t + t \int \frac{v}{t^2} \,dt.
where `C_3` and `C_4` are arbitrary constants.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
u, v = symbols('u, v', cls=Function)
f = -r['c1'] ; g = -r['d1']
h = -r['c2'] ; p = -r['d2']
[msol1, msol2] = dsolve([Eq(diff(u(t),t), t*f*u(t) + t*g*v(t)), Eq(diff(v(t),t), t*h*u(t) + t*p*v(t))])
sol1 = C3*t + t*Integral(msol1.rhs/t**2, t)
sol2 = C4*t + t*Integral(msol2.rhs/t**2, t)
return [Eq(x(t), sol1), Eq(y(t), sol2)]
def sysode_linear_3eq_order1(match_):
x = match_['func'][0].func
y = match_['func'][1].func
z = match_['func'][2].func
func = match_['func']
fc = match_['func_coeff']
eq = match_['eq']
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
r = dict()
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
for i in range(3):
eqs = 0
for terms in Add.make_args(eq[i]):
eqs += terms/fc[i,func[i],1]
eq[i] = eqs
# for equations:
# Eq(g1*diff(x(t),t), a1*x(t)+b1*y(t)+c1*z(t)+d1),
# Eq(g2*diff(y(t),t), a2*x(t)+b2*y(t)+c2*z(t)+d2), and
# Eq(g3*diff(z(t),t), a3*x(t)+b3*y(t)+c3*z(t)+d3)
r['a1'] = fc[0,x(t),0]/fc[0,x(t),1]; r['a2'] = fc[1,x(t),0]/fc[1,y(t),1];
r['a3'] = fc[2,x(t),0]/fc[2,z(t),1]
r['b1'] = fc[0,y(t),0]/fc[0,x(t),1]; r['b2'] = fc[1,y(t),0]/fc[1,y(t),1];
r['b3'] = fc[2,y(t),0]/fc[2,z(t),1]
r['c1'] = fc[0,z(t),0]/fc[0,x(t),1]; r['c2'] = fc[1,z(t),0]/fc[1,y(t),1];
r['c3'] = fc[2,z(t),0]/fc[2,z(t),1]
for i in range(3):
for j in Add.make_args(eq[i]):
if not j.has(x(t), y(t), z(t)):
raise NotImplementedError("Only homogeneous problems are supported, non-homogenous are not supported currently.")
if match_['type_of_equation'] == 'type1':
sol = _linear_3eq_order1_type1(x, y, z, t, r, eq)
if match_['type_of_equation'] == 'type2':
sol = _linear_3eq_order1_type2(x, y, z, t, r, eq)
if match_['type_of_equation'] == 'type3':
sol = _linear_3eq_order1_type3(x, y, z, t, r, eq)
if match_['type_of_equation'] == 'type4':
sol = _linear_3eq_order1_type4(x, y, z, t, r, eq)
if match_['type_of_equation'] == 'type6':
sol = _linear_neq_order1_type1(match_)
return sol
def _linear_3eq_order1_type1(x, y, z, t, r, eq):
r"""
.. math:: x' = ax
.. math:: y' = bx + cy
.. math:: z' = dx + ky + pz
Solution of such equations are forward substitution. Solving first equations
gives the value of `x`, substituting it in second and third equation and
solving second equation gives `y` and similarly substituting `y` in third
equation give `z`.
.. math:: x = C_1 e^{at}
.. math:: y = \frac{b C_1}{a - c} e^{at} + C_2 e^{ct}
.. math:: z = \frac{C_1}{a - p} (d + \frac{bk}{a - c}) e^{at} + \frac{k C_2}{c - p} e^{ct} + C_3 e^{pt}
where `C_1, C_2` and `C_3` are arbitrary constants.
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
a = -r['a1']; b = -r['a2']; c = -r['b2']
d = -r['a3']; k = -r['b3']; p = -r['c3']
sol1 = C1*exp(a*t)
sol2 = b*C1*exp(a*t)/(a-c) + C2*exp(c*t)
sol3 = C1*(d+b*k/(a-c))*exp(a*t)/(a-p) + k*C2*exp(c*t)/(c-p) + C3*exp(p*t)
return [Eq(x(t), sol1), Eq(y(t), sol2), Eq(z(t), sol3)]
def _linear_3eq_order1_type2(x, y, z, t, r, eq):
r"""
The equations of this type are
.. math:: x' = cy - bz
.. math:: y' = az - cx
.. math:: z' = bx - ay
1. First integral:
.. math:: ax + by + cz = A \qquad - (1)
.. math:: x^2 + y^2 + z^2 = B^2 \qquad - (2)
where `A` and `B` are arbitrary constants. It follows from these integrals
that the integral lines are circles formed by the intersection of the planes
`(1)` and sphere `(2)`
2. Solution:
.. math:: x = a C_0 + k C_1 \cos(kt) + (c C_2 - b C_3) \sin(kt)
.. math:: y = b C_0 + k C_2 \cos(kt) + (a C_2 - c C_3) \sin(kt)
.. math:: z = c C_0 + k C_3 \cos(kt) + (b C_2 - a C_3) \sin(kt)
where `k = \sqrt{a^2 + b^2 + c^2}` and the four constants of integration,
`C_1,...,C_4` are constrained by a single relation,
.. math:: a C_1 + b C_2 + c C_3 = 0
"""
C0, C1, C2, C3 = get_numbered_constants(eq, num=4, start=0)
a = -r['c2']; b = -r['a3']; c = -r['b1']
k = sqrt(a**2 + b**2 + c**2)
C3 = (-a*C1 - b*C2)/c
sol1 = a*C0 + k*C1*cos(k*t) + (c*C2-b*C3)*sin(k*t)
sol2 = b*C0 + k*C2*cos(k*t) + (a*C3-c*C1)*sin(k*t)
sol3 = c*C0 + k*C3*cos(k*t) + (b*C1-a*C2)*sin(k*t)
return [Eq(x(t), sol1), Eq(y(t), sol2), Eq(z(t), sol3)]
def _linear_3eq_order1_type3(x, y, z, t, r, eq):
r"""
Equations of this system of ODEs
.. math:: a x' = bc (y - z)
.. math:: b y' = ac (z - x)
.. math:: c z' = ab (x - y)
1. First integral:
.. math:: a^2 x + b^2 y + c^2 z = A
where A is an arbitrary constant. It follows that the integral lines are plane curves.
2. Solution:
.. math:: x = C_0 + k C_1 \cos(kt) + a^{-1} bc (C_2 - C_3) \sin(kt)
.. math:: y = C_0 + k C_2 \cos(kt) + a b^{-1} c (C_3 - C_1) \sin(kt)
.. math:: z = C_0 + k C_3 \cos(kt) + ab c^{-1} (C_1 - C_2) \sin(kt)
where `k = \sqrt{a^2 + b^2 + c^2}` and the four constants of integration,
`C_1,...,C_4` are constrained by a single relation
.. math:: a^2 C_1 + b^2 C_2 + c^2 C_3 = 0
"""
C0, C1, C2, C3 = get_numbered_constants(eq, num=4, start=0)
c = sqrt(r['b1']*r['c2'])
b = sqrt(r['b1']*r['a3'])
a = sqrt(r['c2']*r['a3'])
C3 = (-a**2*C1-b**2*C2)/c**2
k = sqrt(a**2 + b**2 + c**2)
sol1 = C0 + k*C1*cos(k*t) + a**-1*b*c*(C2-C3)*sin(k*t)
sol2 = C0 + k*C2*cos(k*t) + a*b**-1*c*(C3-C1)*sin(k*t)
sol3 = C0 + k*C3*cos(k*t) + a*b*c**-1*(C1-C2)*sin(k*t)
return [Eq(x(t), sol1), Eq(y(t), sol2), Eq(z(t), sol3)]
def _linear_3eq_order1_type4(x, y, z, t, r, eq):
r"""
Equations:
.. math:: x' = (a_1 f(t) + g(t)) x + a_2 f(t) y + a_3 f(t) z
.. math:: y' = b_1 f(t) x + (b_2 f(t) + g(t)) y + b_3 f(t) z
.. math:: z' = c_1 f(t) x + c_2 f(t) y + (c_3 f(t) + g(t)) z
The transformation
.. math:: x = e^{\int g(t) \,dt} u, y = e^{\int g(t) \,dt} v, z = e^{\int g(t) \,dt} w, \tau = \int f(t) \,dt
leads to the system of constant coefficient linear differential equations
.. math:: u' = a_1 u + a_2 v + a_3 w
.. math:: v' = b_1 u + b_2 v + b_3 w
.. math:: w' = c_1 u + c_2 v + c_3 w
These system of equations are solved by homogeneous linear system of constant
coefficients of `n` equations of first order. Then substituting the value of
`u, v` and `w` in transformed equation gives value of `x, y` and `z`.
"""
u, v, w = symbols('u, v, w', cls=Function)
a2, a3 = cancel(r['b1']/r['c1']).as_numer_denom()
f = cancel(r['b1']/a2)
b1 = cancel(r['a2']/f); b3 = cancel(r['c2']/f)
c1 = cancel(r['a3']/f); c2 = cancel(r['b3']/f)
a1, g = div(r['a1'],f)
b2 = div(r['b2'],f)[0]
c3 = div(r['c3'],f)[0]
trans_eq = (diff(u(t),t)-a1*u(t)-a2*v(t)-a3*w(t), diff(v(t),t)-b1*u(t)-\
b2*v(t)-b3*w(t), diff(w(t),t)-c1*u(t)-c2*v(t)-c3*w(t))
sol = dsolve(trans_eq)
sol1 = exp(Integral(g,t))*((sol[0].rhs).subs(t, Integral(f,t)))
sol2 = exp(Integral(g,t))*((sol[1].rhs).subs(t, Integral(f,t)))
sol3 = exp(Integral(g,t))*((sol[2].rhs).subs(t, Integral(f,t)))
return [Eq(x(t), sol1), Eq(y(t), sol2), Eq(z(t), sol3)]
def sysode_linear_neq_order1(match_):
sol = _linear_neq_order1_type1(match_)
return sol
def _linear_neq_order1_type1(match_):
r"""
System of n first-order constant-coefficient linear nonhomogeneous differential equation
.. math:: y'_k = a_{k1} y_1 + a_{k2} y_2 +...+ a_{kn} y_n; k = 1,2,...,n
or that can be written as `\vec{y'} = A . \vec{y}`
where `\vec{y}` is matrix of `y_k` for `k = 1,2,...n` and `A` is a `n \times n` matrix.
Since these equations are equivalent to a first order homogeneous linear
differential equation. So the general solution will contain `n` linearly
independent parts and solution will consist some type of exponential
functions. Assuming `y = \vec{v} e^{rt}` is a solution of the system where
`\vec{v}` is a vector of coefficients of `y_1,...,y_n`. Substituting `y` and
`y' = r v e^{r t}` into the equation `\vec{y'} = A . \vec{y}`, we get
.. math:: r \vec{v} e^{rt} = A \vec{v} e^{rt}
.. math:: r \vec{v} = A \vec{v}
where `r` comes out to be eigenvalue of `A` and vector `\vec{v}` is the eigenvector
of `A` corresponding to `r`. There are three possibilities of eigenvalues of `A`
- `n` distinct real eigenvalues
- complex conjugate eigenvalues
- eigenvalues with multiplicity `k`
1. When all eigenvalues `r_1,..,r_n` are distinct with `n` different eigenvectors
`v_1,...v_n` then the solution is given by
.. math:: \vec{y} = C_1 e^{r_1 t} \vec{v_1} + C_2 e^{r_2 t} \vec{v_2} +...+ C_n e^{r_n t} \vec{v_n}
where `C_1,C_2,...,C_n` are arbitrary constants.
2. When some eigenvalues are complex then in order to make the solution real,
we take a linear combination: if `r = a + bi` has an eigenvector
`\vec{v} = \vec{w_1} + i \vec{w_2}` then to obtain real-valued solutions to
the system, replace the complex-valued solutions `e^{rx} \vec{v}`
with real-valued solution `e^{ax} (\vec{w_1} \cos(bx) - \vec{w_2} \sin(bx))`
and for `r = a - bi` replace the solution `e^{-r x} \vec{v}` with
`e^{ax} (\vec{w_1} \sin(bx) + \vec{w_2} \cos(bx))`
3. If some eigenvalues are repeated. Then we get fewer than `n` linearly
independent eigenvectors, we miss some of the solutions and need to
construct the missing ones. We do this via generalized eigenvectors, vectors
which are not eigenvectors but are close enough that we can use to write
down the remaining solutions. For a eigenvalue `r` with eigenvector `\vec{w}`
we obtain `\vec{w_2},...,\vec{w_k}` using
.. math:: (A - r I) . \vec{w_2} = \vec{w}
.. math:: (A - r I) . \vec{w_3} = \vec{w_2}
.. math:: \vdots
.. math:: (A - r I) . \vec{w_k} = \vec{w_{k-1}}
Then the solutions to the system for the eigenspace are `e^{rt} [\vec{w}],
e^{rt} [t \vec{w} + \vec{w_2}], e^{rt} [\frac{t^2}{2} \vec{w} + t \vec{w_2} + \vec{w_3}],
...,e^{rt} [\frac{t^{k-1}}{(k-1)!} \vec{w} + \frac{t^{k-2}}{(k-2)!} \vec{w_2} +...+ t \vec{w_{k-1}}
+ \vec{w_k}]`
So, If `\vec{y_1},...,\vec{y_n}` are `n` solution of obtained from three
categories of `A`, then general solution to the system `\vec{y'} = A . \vec{y}`
.. math:: \vec{y} = C_1 \vec{y_1} + C_2 \vec{y_2} + \cdots + C_n \vec{y_n}
"""
eq = match_['eq']
func = match_['func']
fc = match_['func_coeff']
n = len(eq)
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
constants = numbered_symbols(prefix='C', cls=Symbol, start=1)
M = Matrix(n,n,lambda i,j:-fc[i,func[j],0])
evector = M.eigenvects(simplify=True)
def is_complex(mat, root):
return Matrix(n, 1, lambda i,j: re(mat[i])*cos(im(root)*t) - im(mat[i])*sin(im(root)*t))
def is_complex_conjugate(mat, root):
return Matrix(n, 1, lambda i,j: re(mat[i])*sin(abs(im(root))*t) + im(mat[i])*cos(im(root)*t)*abs(im(root))/im(root))
conjugate_root = []
e_vector = zeros(n,1)
for evects in evector:
if evects[0] not in conjugate_root:
# If number of column of an eigenvector is not equal to the multiplicity
# of its eigenvalue then the legt eigenvectors are calculated
if len(evects[2])!=evects[1]:
var_mat = Matrix(n, 1, lambda i,j: Symbol('x'+str(i)))
Mnew = (M - evects[0]*eye(evects[2][-1].rows))*var_mat
w = [0 for i in range(evects[1])]
w[0] = evects[2][-1]
for r in range(1, evects[1]):
w_ = Mnew - w[r-1]
sol_dict = solve(list(w_), var_mat[1:])
sol_dict[var_mat[0]] = var_mat[0]
for key, value in sol_dict.items():
sol_dict[key] = value.subs(var_mat[0],1)
w[r] = Matrix(n, 1, lambda i,j: sol_dict[var_mat[i]])
evects[2].append(w[r])
for i in range(evects[1]):
C = next(constants)
for j in range(i+1):
if evects[0].has(I):
evects[2][j] = simplify(evects[2][j])
e_vector += C*is_complex(evects[2][j], evects[0])*t**(i-j)*exp(re(evects[0])*t)/factorial(i-j)
C = next(constants)
e_vector += C*is_complex_conjugate(evects[2][j], evects[0])*t**(i-j)*exp(re(evects[0])*t)/factorial(i-j)
else:
e_vector += C*evects[2][j]*t**(i-j)*exp(evects[0]*t)/factorial(i-j)
if evects[0].has(I):
conjugate_root.append(conjugate(evects[0]))
sol = []
for i in range(len(eq)):
sol.append(Eq(func[i],e_vector[i]))
return sol
def sysode_nonlinear_2eq_order1(match_):
func = match_['func']
eq = match_['eq']
fc = match_['func_coeff']
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
if match_['type_of_equation'] == 'type5':
sol = _nonlinear_2eq_order1_type5(func, t, eq)
return sol
x = func[0].func
y = func[1].func
for i in range(2):
eqs = 0
for terms in Add.make_args(eq[i]):
eqs += terms/fc[i,func[i],1]
eq[i] = eqs
if match_['type_of_equation'] == 'type1':
sol = _nonlinear_2eq_order1_type1(x, y, t, eq)
elif match_['type_of_equation'] == 'type2':
sol = _nonlinear_2eq_order1_type2(x, y, t, eq)
elif match_['type_of_equation'] == 'type3':
sol = _nonlinear_2eq_order1_type3(x, y, t, eq)
elif match_['type_of_equation'] == 'type4':
sol = _nonlinear_2eq_order1_type4(x, y, t, eq)
return sol
def _nonlinear_2eq_order1_type1(x, y, t, eq):
r"""
Equations:
.. math:: x' = x^n F(x,y)
.. math:: y' = g(y) F(x,y)
Solution:
.. math:: x = \varphi(y), \int \frac{1}{g(y) F(\varphi(y),y)} \,dy = t + C_2
where
if `n \neq 1`
.. math:: \varphi = [C_1 + (1-n) \int \frac{1}{g(y)} \,dy]^{\frac{1}{1-n}}
if `n = 1`
.. math:: \varphi = C_1 e^{\int \frac{1}{g(y)} \,dy}
where `C_1` and `C_2` are arbitrary constants.
"""
C1, C2 = get_numbered_constants(eq, num=2)
n = Wild('n', exclude=[x(t),y(t)])
f = Wild('f')
u, v = symbols('u, v')
r = eq[0].match(diff(x(t),t) - x(t)**n*f)
g = ((diff(y(t),t) - eq[1])/r[f]).subs(y(t),v)
F = r[f].subs(x(t),u).subs(y(t),v)
n = r[n]
if n!=1:
phi = (C1 + (1-n)*Integral(1/g, v))**(1/(1-n))
else:
phi = C1*exp(Integral(1/g, v))
phi = phi.doit()
sol2 = solve(Integral(1/(g*F.subs(u,phi)), v).doit() - t - C2, v)
sol = []
for sols in sol2:
sol.append(Eq(x(t),phi.subs(v, sols)))
sol.append(Eq(y(t), sols))
return sol
def _nonlinear_2eq_order1_type2(x, y, t, eq):
r"""
Equations:
.. math:: x' = e^{\lambda x} F(x,y)
.. math:: y' = g(y) F(x,y)
Solution:
.. math:: x = \varphi(y), \int \frac{1}{g(y) F(\varphi(y),y)} \,dy = t + C_2
where
if `\lambda \neq 0`
.. math:: \varphi = -\frac{1}{\lambda} log(C_1 - \lambda \int \frac{1}{g(y)} \,dy)
if `\lambda = 0`
.. math:: \varphi = C_1 + \int \frac{1}{g(y)} \,dy
where `C_1` and `C_2` are arbitrary constants.
"""
C1, C2 = get_numbered_constants(eq, num=2)
n = Wild('n', exclude=[x(t),y(t)])
f = Wild('f')
u, v = symbols('u, v')
r = eq[0].match(diff(x(t),t) - exp(n*x(t))*f)
g = ((diff(y(t),t) - eq[1])/r[f]).subs(y(t),v)
F = r[f].subs(x(t),u).subs(y(t),v)
n = r[n]
if n:
phi = -1/n*log(C1 - n*Integral(1/g, v))
else:
phi = C1 + Integral(1/g, v)
phi = phi.doit()
sol2 = solve(Integral(1/(g*F.subs(u,phi)), v).doit() - t - C2, v)
sol = []
for sols in sol2:
sol.append(Eq(x(t),phi.subs(v, sols)))
sol.append(Eq(y(t), sols))
return sol
def _nonlinear_2eq_order1_type3(x, y, t, eq):
r"""
Autonomous system of general form
.. math:: x' = F(x,y)
.. math:: y' = G(x,y)
Assuming `y = y(x, C_1)` where `C_1` is an arbitrary constant is the general
solution of the first-order equation
.. math:: F(x,y) y'_x = G(x,y)
Then the general solution of the original system of equations has the form
.. math:: \int \frac{1}{F(x,y(x,C_1))} \,dx = t + C_1
"""
C1, C2, C3, C4 = get_numbered_constants(eq, num=4)
v = Function('v')
u = Symbol('u')
f = Wild('f')
g = Wild('g')
r1 = eq[0].match(diff(x(t),t) - f)
r2 = eq[1].match(diff(y(t),t) - g)
F = r1[f].subs(x(t), u).subs(y(t), v(u))
G = r2[g].subs(x(t), u).subs(y(t), v(u))
sol2r = dsolve(Eq(diff(v(u), u), G/F))
for sol2s in sol2r:
sol1 = solve(Integral(1/F.subs(v(u), sol2s.rhs), u).doit() - t - C2, u)
sol = []
for sols in sol1:
sol.append(Eq(x(t), sols))
sol.append(Eq(y(t), (sol2s.rhs).subs(u, sols)))
return sol
def _nonlinear_2eq_order1_type4(x, y, t, eq):
r"""
Equation:
.. math:: x' = f_1(x) g_1(y) \phi(x,y,t)
.. math:: y' = f_2(x) g_2(y) \phi(x,y,t)
First integral:
.. math:: \int \frac{f_2(x)}{f_1(x)} \,dx - \int \frac{g_1(y)}{g_2(y)} \,dy = C
where `C` is an arbitrary constant.
On solving the first integral for `x` (resp., `y` ) and on substituting the
resulting expression into either equation of the original solution, one
arrives at a first-order equation for determining `y` (resp., `x` ).
"""
C1, C2 = get_numbered_constants(eq, num=2)
u, v = symbols('u, v')
U, V = symbols('U, V', cls=Function)
f = Wild('f')
g = Wild('g')
f1 = Wild('f1', exclude=[v,t])
f2 = Wild('f2', exclude=[v,t])
g1 = Wild('g1', exclude=[u,t])
g2 = Wild('g2', exclude=[u,t])
r1 = eq[0].match(diff(x(t),t) - f)
r2 = eq[1].match(diff(y(t),t) - g)
num, den = (
(r1[f].subs(x(t),u).subs(y(t),v))/
(r2[g].subs(x(t),u).subs(y(t),v))).as_numer_denom()
R1 = num.match(f1*g1)
R2 = den.match(f2*g2)
phi = (r1[f].subs(x(t),u).subs(y(t),v))/num
F1 = R1[f1]; F2 = R2[f2]
G1 = R1[g1]; G2 = R2[g2]
sol1r = solve(Integral(F2/F1, u).doit() - Integral(G1/G2,v).doit() - C1, u)
sol2r = solve(Integral(F2/F1, u).doit() - Integral(G1/G2,v).doit() - C1, v)
sol = []
for sols in sol1r:
sol.append(Eq(y(t), dsolve(diff(V(t),t) - F2.subs(u,sols).subs(v,V(t))*G2.subs(v,V(t))*phi.subs(u,sols).subs(v,V(t))).rhs))
for sols in sol2r:
sol.append(Eq(x(t), dsolve(diff(U(t),t) - F1.subs(u,U(t))*G1.subs(v,sols).subs(u,U(t))*phi.subs(v,sols).subs(u,U(t))).rhs))
return set(sol)
def _nonlinear_2eq_order1_type5(func, t, eq):
r"""
Clairaut system of ODEs
.. math:: x = t x' + F(x',y')
.. math:: y = t y' + G(x',y')
The following are solutions of the system
`(i)` straight lines:
.. math:: x = C_1 t + F(C_1, C_2), y = C_2 t + G(C_1, C_2)
where `C_1` and `C_2` are arbitrary constants;
`(ii)` envelopes of the above lines;
`(iii)` continuously differentiable lines made up from segments of the lines
`(i)` and `(ii)`.
"""
C1, C2 = get_numbered_constants(eq, num=2)
f = Wild('f')
g = Wild('g')
def check_type(x, y):
r1 = eq[0].match(t*diff(x(t),t) - x(t) + f)
r2 = eq[1].match(t*diff(y(t),t) - y(t) + g)
if not (r1 and r2):
r1 = eq[0].match(diff(x(t),t) - x(t)/t + f/t)
r2 = eq[1].match(diff(y(t),t) - y(t)/t + g/t)
if not (r1 and r2):
r1 = (-eq[0]).match(t*diff(x(t),t) - x(t) + f)
r2 = (-eq[1]).match(t*diff(y(t),t) - y(t) + g)
if not (r1 and r2):
r1 = (-eq[0]).match(diff(x(t),t) - x(t)/t + f/t)
r2 = (-eq[1]).match(diff(y(t),t) - y(t)/t + g/t)
return [r1, r2]
for func_ in func:
if isinstance(func_, list):
x = func[0][0].func
y = func[0][1].func
[r1, r2] = check_type(x, y)
if not (r1 and r2):
[r1, r2] = check_type(y, x)
x, y = y, x
x1 = diff(x(t),t); y1 = diff(y(t),t)
return {Eq(x(t), C1*t + r1[f].subs(x1,C1).subs(y1,C2)), Eq(y(t), C2*t + r2[g].subs(x1,C1).subs(y1,C2))}
def sysode_nonlinear_3eq_order1(match_):
x = match_['func'][0].func
y = match_['func'][1].func
z = match_['func'][2].func
eq = match_['eq']
fc = match_['func_coeff']
func = match_['func']
t = list(list(eq[0].atoms(Derivative))[0].atoms(Symbol))[0]
if match_['type_of_equation'] == 'type1':
sol = _nonlinear_3eq_order1_type1(x, y, z, t, eq)
if match_['type_of_equation'] == 'type2':
sol = _nonlinear_3eq_order1_type2(x, y, z, t, eq)
if match_['type_of_equation'] == 'type3':
sol = _nonlinear_3eq_order1_type3(x, y, z, t, eq)
if match_['type_of_equation'] == 'type4':
sol = _nonlinear_3eq_order1_type4(x, y, z, t, eq)
if match_['type_of_equation'] == 'type5':
sol = _nonlinear_3eq_order1_type5(x, y, z, t, eq)
return sol
def _nonlinear_3eq_order1_type1(x, y, z, t, eq):
r"""
Equations:
.. math:: a x' = (b - c) y z, \enspace b y' = (c - a) z x, \enspace c z' = (a - b) x y
First Integrals:
.. math:: a x^{2} + b y^{2} + c z^{2} = C_1
.. math:: a^{2} x^{2} + b^{2} y^{2} + c^{2} z^{2} = C_2
where `C_1` and `C_2` are arbitrary constants. On solving the integrals for `y` and
`z` and on substituting the resulting expressions into the first equation of the
system, we arrives at a separable first-order equation on `x`. Similarly doing that
for other two equations, we will arrive at first order equation on `y` and `z` too.
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode0401.pdf
"""
C1, C2 = get_numbered_constants(eq, num=2)
u, v, w = symbols('u, v, w')
p = Wild('p', exclude=[x(t), y(t), z(t), t])
q = Wild('q', exclude=[x(t), y(t), z(t), t])
s = Wild('s', exclude=[x(t), y(t), z(t), t])
r = (diff(x(t),t) - eq[0]).match(p*y(t)*z(t))
r.update((diff(y(t),t) - eq[1]).match(q*z(t)*x(t)))
r.update((diff(z(t),t) - eq[2]).match(s*x(t)*y(t)))
n1, d1 = r[p].as_numer_denom()
n2, d2 = r[q].as_numer_denom()
n3, d3 = r[s].as_numer_denom()
val = solve([n1*u-d1*v+d1*w, d2*u+n2*v-d2*w, d3*u-d3*v-n3*w],[u,v])
vals = [val[v], val[u]]
c = lcm(vals[0].as_numer_denom()[1], vals[1].as_numer_denom()[1])
b = vals[0].subs(w,c)
a = vals[1].subs(w,c)
y_x = sqrt(((c*C1-C2) - a*(c-a)*x(t)**2)/(b*(c-b)))
z_x = sqrt(((b*C1-C2) - a*(b-a)*x(t)**2)/(c*(b-c)))
z_y = sqrt(((a*C1-C2) - b*(a-b)*y(t)**2)/(c*(a-c)))
x_y = sqrt(((c*C1-C2) - b*(c-b)*y(t)**2)/(a*(c-a)))
x_z = sqrt(((b*C1-C2) - c*(b-c)*z(t)**2)/(a*(b-a)))
y_z = sqrt(((a*C1-C2) - c*(a-c)*z(t)**2)/(b*(a-b)))
sol1 = dsolve(a*diff(x(t),t) - (b-c)*y_x*z_x)
sol2 = dsolve(b*diff(y(t),t) - (c-a)*z_y*x_y)
sol3 = dsolve(c*diff(z(t),t) - (a-b)*x_z*y_z)
return [sol1, sol2, sol3]
def _nonlinear_3eq_order1_type2(x, y, z, t, eq):
r"""
Equations:
.. math:: a x' = (b - c) y z f(x, y, z, t)
.. math:: b y' = (c - a) z x f(x, y, z, t)
.. math:: c z' = (a - b) x y f(x, y, z, t)
First Integrals:
.. math:: a x^{2} + b y^{2} + c z^{2} = C_1
.. math:: a^{2} x^{2} + b^{2} y^{2} + c^{2} z^{2} = C_2
where `C_1` and `C_2` are arbitrary constants. On solving the integrals for `y` and
`z` and on substituting the resulting expressions into the first equation of the
system, we arrives at a first-order differential equations on `x`. Similarly doing
that for other two equations we will arrive at first order equation on `y` and `z`.
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode0402.pdf
"""
C1, C2 = get_numbered_constants(eq, num=2)
u, v, w = symbols('u, v, w')
p = Wild('p', exclude=[x(t), y(t), z(t), t])
q = Wild('q', exclude=[x(t), y(t), z(t), t])
s = Wild('s', exclude=[x(t), y(t), z(t), t])
f = Wild('f')
r1 = (diff(x(t),t) - eq[0]).match(y(t)*z(t)*f)
r = collect_const(r1[f]).match(p*f)
r.update(((diff(y(t),t) - eq[1])/r[f]).match(q*z(t)*x(t)))
r.update(((diff(z(t),t) - eq[2])/r[f]).match(s*x(t)*y(t)))
n1, d1 = r[p].as_numer_denom()
n2, d2 = r[q].as_numer_denom()
n3, d3 = r[s].as_numer_denom()
val = solve([n1*u-d1*v+d1*w, d2*u+n2*v-d2*w, -d3*u+d3*v+n3*w],[u,v])
vals = [val[v], val[u]]
c = lcm(vals[0].as_numer_denom()[1], vals[1].as_numer_denom()[1])
a = vals[0].subs(w,c)
b = vals[1].subs(w,c)
y_x = sqrt(((c*C1-C2) - a*(c-a)*x(t)**2)/(b*(c-b)))
z_x = sqrt(((b*C1-C2) - a*(b-a)*x(t)**2)/(c*(b-c)))
z_y = sqrt(((a*C1-C2) - b*(a-b)*y(t)**2)/(c*(a-c)))
x_y = sqrt(((c*C1-C2) - b*(c-b)*y(t)**2)/(a*(c-a)))
x_z = sqrt(((b*C1-C2) - c*(b-c)*z(t)**2)/(a*(b-a)))
y_z = sqrt(((a*C1-C2) - c*(a-c)*z(t)**2)/(b*(a-b)))
sol1 = dsolve(a*diff(x(t),t) - (b-c)*y_x*z_x*r[f])
sol2 = dsolve(b*diff(y(t),t) - (c-a)*z_y*x_y*r[f])
sol3 = dsolve(c*diff(z(t),t) - (a-b)*x_z*y_z*r[f])
return [sol1, sol2, sol3]
def _nonlinear_3eq_order1_type3(x, y, z, t, eq):
r"""
Equations:
.. math:: x' = c F_2 - b F_3, \enspace y' = a F_3 - c F_1, \enspace z' = b F_1 - a F_2
where `F_n = F_n(x, y, z, t)`.
1. First Integral:
.. math:: a x + b y + c z = C_1,
where C is an arbitrary constant.
2. If we assume function `F_n` to be independent of `t`,i.e, `F_n` = `F_n (x, y, z)`
Then, on eliminating `t` and `z` from the first two equation of the system, one
arrives at the first-order equation
.. math:: \frac{dy}{dx} = \frac{a F_3 (x, y, z) - c F_1 (x, y, z)}{c F_2 (x, y, z) -
b F_3 (x, y, z)}
where `z = \frac{1}{c} (C_1 - a x - b y)`
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode0404.pdf
"""
C1 = get_numbered_constants(eq, num=1)
u, v, w = symbols('u, v, w')
p = Wild('p', exclude=[x(t), y(t), z(t), t])
q = Wild('q', exclude=[x(t), y(t), z(t), t])
s = Wild('s', exclude=[x(t), y(t), z(t), t])
F1, F2, F3 = symbols('F1, F2, F3', cls=Wild)
r1 = (diff(x(t),t) - eq[0]).match(F2-F3)
r = collect_const(r1[F2]).match(s*F2)
r.update(collect_const(r1[F3]).match(q*F3))
if eq[1].has(r[F2]) and not eq[1].has(r[F3]):
r[F2], r[F3] = r[F3], r[F2]
r[s], r[q] = -r[q], -r[s]
r.update((diff(y(t),t) - eq[1]).match(p*r[F3] - r[s]*F1))
a = r[p]; b = r[q]; c = r[s]
F1 = r[F1].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F2 = r[F2].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F3 = r[F3].subs(x(t),u).subs(y(t),v).subs(z(t),w)
z_xy = (C1-a*u-b*v)/c
y_zx = (C1-a*u-c*w)/b
x_yz = (C1-b*v-c*w)/a
y_x = dsolve(diff(v(u),u) - ((a*F3-c*F1)/(c*F2-b*F3)).subs(w,z_xy).subs(v,v(u))).rhs
z_x = dsolve(diff(w(u),u) - ((b*F1-a*F2)/(c*F2-b*F3)).subs(v,y_zx).subs(w,w(u))).rhs
z_y = dsolve(diff(w(v),v) - ((b*F1-a*F2)/(a*F3-c*F1)).subs(u,x_yz).subs(w,w(v))).rhs
x_y = dsolve(diff(u(v),v) - ((c*F2-b*F3)/(a*F3-c*F1)).subs(w,z_xy).subs(u,u(v))).rhs
y_z = dsolve(diff(v(w),w) - ((a*F3-c*F1)/(b*F1-a*F2)).subs(u,x_yz).subs(v,v(w))).rhs
x_z = dsolve(diff(u(w),w) - ((c*F2-b*F3)/(b*F1-a*F2)).subs(v,y_zx).subs(u,u(w))).rhs
sol1 = dsolve(diff(u(t),t) - (c*F2 - b*F3).subs(v,y_x).subs(w,z_x).subs(u,u(t))).rhs
sol2 = dsolve(diff(v(t),t) - (a*F3 - c*F1).subs(u,x_y).subs(w,z_y).subs(v,v(t))).rhs
sol3 = dsolve(diff(w(t),t) - (b*F1 - a*F2).subs(u,x_z).subs(v,y_z).subs(w,w(t))).rhs
return [sol1, sol2, sol3]
def _nonlinear_3eq_order1_type4(x, y, z, t, eq):
r"""
Equations:
.. math:: x' = c z F_2 - b y F_3, \enspace y' = a x F_3 - c z F_1, \enspace z' = b y F_1 - a x F_2
where `F_n = F_n (x, y, z, t)`
1. First integral:
.. math:: a x^{2} + b y^{2} + c z^{2} = C_1
where `C` is an arbitrary constant.
2. Assuming the function `F_n` is independent of `t`: `F_n = F_n (x, y, z)`. Then on
eliminating `t` and `z` from the first two equations of the system, one arrives at
the first-order equation
.. math:: \frac{dy}{dx} = \frac{a x F_3 (x, y, z) - c z F_1 (x, y, z)}
{c z F_2 (x, y, z) - b y F_3 (x, y, z)}
where `z = \pm \sqrt{\frac{1}{c} (C_1 - a x^{2} - b y^{2})}`
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode0405.pdf
"""
C1 = get_numbered_constants(eq, num=1)
u, v, w = symbols('u, v, w')
p = Wild('p', exclude=[x(t), y(t), z(t), t])
q = Wild('q', exclude=[x(t), y(t), z(t), t])
s = Wild('s', exclude=[x(t), y(t), z(t), t])
F1, F2, F3 = symbols('F1, F2, F3', cls=Wild)
r1 = eq[0].match(diff(x(t),t) - z(t)*F2 + y(t)*F3)
r = collect_const(r1[F2]).match(s*F2)
r.update(collect_const(r1[F3]).match(q*F3))
if eq[1].has(r[F2]) and not eq[1].has(r[F3]):
r[F2], r[F3] = r[F3], r[F2]
r[s], r[q] = -r[q], -r[s]
r.update((diff(y(t),t) - eq[1]).match(p*x(t)*r[F3] - r[s]*z(t)*F1))
a = r[p]; b = r[q]; c = r[s]
F1 = r[F1].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F2 = r[F2].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F3 = r[F3].subs(x(t),u).subs(y(t),v).subs(z(t),w)
x_yz = sqrt((C1 - b*v**2 - c*w**2)/a)
y_zx = sqrt((C1 - c*w**2 - a*u**2)/b)
z_xy = sqrt((C1 - a*u**2 - b*v**2)/c)
y_x = dsolve(diff(v(u),u) - ((a*u*F3-c*w*F1)/(c*w*F2-b*v*F3)).subs(w,z_xy).subs(v,v(u))).rhs
z_x = dsolve(diff(w(u),u) - ((b*v*F1-a*u*F2)/(c*w*F2-b*v*F3)).subs(v,y_zx).subs(w,w(u))).rhs
z_y = dsolve(diff(w(v),v) - ((b*v*F1-a*u*F2)/(a*u*F3-c*w*F1)).subs(u,x_yz).subs(w,w(v))).rhs
x_y = dsolve(diff(u(v),v) - ((c*w*F2-b*v*F3)/(a*u*F3-c*w*F1)).subs(w,z_xy).subs(u,u(v))).rhs
y_z = dsolve(diff(v(w),w) - ((a*u*F3-c*w*F1)/(b*v*F1-a*u*F2)).subs(u,x_yz).subs(v,v(w))).rhs
x_z = dsolve(diff(u(w),w) - ((c*w*F2-b*v*F3)/(b*v*F1-a*u*F2)).subs(v,y_zx).subs(u,u(w))).rhs
sol1 = dsolve(diff(u(t),t) - (c*w*F2 - b*v*F3).subs(v,y_x).subs(w,z_x).subs(u,u(t))).rhs
sol2 = dsolve(diff(v(t),t) - (a*u*F3 - c*w*F1).subs(u,x_y).subs(w,z_y).subs(v,v(t))).rhs
sol3 = dsolve(diff(w(t),t) - (b*v*F1 - a*u*F2).subs(u,x_z).subs(v,y_z).subs(w,w(t))).rhs
return [sol1, sol2, sol3]
def _nonlinear_3eq_order1_type5(x, y, t, eq):
r"""
.. math:: x' = x (c F_2 - b F_3), \enspace y' = y (a F_3 - c F_1), \enspace z' = z (b F_1 - a F_2)
where `F_n = F_n (x, y, z, t)` and are arbitrary functions.
First Integral:
.. math:: \left|x\right|^{a} \left|y\right|^{b} \left|z\right|^{c} = C_1
where `C` is an arbitrary constant. If the function `F_n` is independent of `t`,
then, by eliminating `t` and `z` from the first two equations of the system, one
arrives at a first-order equation.
References
==========
-http://eqworld.ipmnet.ru/en/solutions/sysode/sode0406.pdf
"""
C1 = get_numbered_constants(eq, num=1)
u, v, w = symbols('u, v, w')
p = Wild('p', exclude=[x(t), y(t), z(t), t])
q = Wild('q', exclude=[x(t), y(t), z(t), t])
s = Wild('s', exclude=[x(t), y(t), z(t), t])
F1, F2, F3 = symbols('F1, F2, F3', cls=Wild)
r1 = eq[0].match(diff(x(t),t) - x(t)*(F2 - F3))
r = collect_const(r1[F2]).match(s*F2)
r.update(collect_const(r1[F3]).match(q*F3))
if eq[1].has(r[F2]) and not eq[1].has(r[F3]):
r[F2], r[F3] = r[F3], r[F2]
r[s], r[q] = -r[q], -r[s]
r.update((diff(y(t),t) - eq[1]).match(y(t)*(a*r[F3] - r[c]*F1)))
a = r[p]; b = r[q]; c = r[s]
F1 = r[F1].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F2 = r[F2].subs(x(t),u).subs(y(t),v).subs(z(t),w)
F3 = r[F3].subs(x(t),u).subs(y(t),v).subs(z(t),w)
x_yz = (C1*v**-b*w**-c)**-a
y_zx = (C1*w**-c*u**-a)**-b
z_xy = (C1*u**-a*v**-b)**-c
y_x = dsolve(diff(v(u),u) - ((v*(a*F3-c*F1))/(u*(c*F2-b*F3))).subs(w,z_xy).subs(v,v(u))).rhs
z_x = dsolve(diff(w(u),u) - ((w*(b*F1-a*F2))/(u*(c*F2-b*F3))).subs(v,y_zx).subs(w,w(u))).rhs
z_y = dsolve(diff(w(v),v) - ((w*(b*F1-a*F2))/(v*(a*F3-c*F1))).subs(u,x_yz).subs(w,w(v))).rhs
x_y = dsolve(diff(u(v),v) - ((u*(c*F2-b*F3))/(v*(a*F3-c*F1))).subs(w,z_xy).subs(u,u(v))).rhs
y_z = dsolve(diff(v(w),w) - ((v*(a*F3-c*F1))/(w*(b*F1-a*F2))).subs(u,x_yz).subs(v,v(w))).rhs
x_z = dsolve(diff(u(w),w) - ((u*(c*F2-b*F3))/(w*(b*F1-a*F2))).subs(v,y_zx).subs(u,u(w))).rhs
sol1 = dsolve(diff(u(t),t) - (u*(c*F2-b*F3)).subs(v,y_x).subs(w,z_x).subs(u,u(t))).rhs
sol2 = dsolve(diff(v(t),t) - (v*(a*F3-c*F1)).subs(u,x_y).subs(w,z_y).subs(v,v(t))).rhs
sol3 = dsolve(diff(w(t),t) - (w*(b*F1-a*F2)).subs(u,x_z).subs(v,y_z).subs(w,w(t))).rhs
return [sol1, sol2, sol3]
|
90c026e56dd371d737adc2059ca48d404b1104adfbbcd972841226982426f0a5
|
"""
Singularities
=============
This module implements algorithms for finding singularities for a function
and identifying types of functions.
The differential calculus methods in this module include methods to identify
the following function types in the given ``Interval``:
- Increasing
- Strictly Increasing
- Decreasing
- Strictly Decreasing
- Monotonic
"""
from sympy.core.sympify import sympify
from sympy.solvers.solveset import solveset
from sympy.simplify import simplify
from sympy import S, Symbol
def singularities(expression, symbol):
"""
Find singularities of a given function.
Parameters
==========
expression : Expr
The target function in which singularities need to be found.
symbol : Symbol
The symbol over the values of which the singularity in
expression in being searched for.
Returns
=======
Set
A set of values for ``symbol`` for which ``expression`` has a
singularity. An ``EmptySet`` is returned if ``expression`` has no
singularities for any given value of ``Symbol``.
Raises
======
NotImplementedError
The algorithm to find singularities for irrational functions
has not been implemented yet.
Notes
=====
This function does not find non-isolated singularities
nor does it find branch points of the expression.
Currently supported functions are:
- univariate rational (real or complex) functions
References
==========
.. [1] https://en.wikipedia.org/wiki/Mathematical_singularity
Examples
========
>>> from sympy.calculus.singularities import singularities
>>> from sympy import Symbol
>>> x = Symbol('x', real=True)
>>> y = Symbol('y', real=False)
>>> singularities(x**2 + x + 1, x)
EmptySet()
>>> singularities(1/(x + 1), x)
{-1}
>>> singularities(1/(y**2 + 1), y)
{-I, I}
>>> singularities(1/(y**3 + 1), y)
{-1, 1/2 - sqrt(3)*I/2, 1/2 + sqrt(3)*I/2}
"""
if not expression.is_rational_function(symbol):
raise NotImplementedError(
"Algorithms finding singularities for non-rational"
" functions are not yet implemented."
)
else:
domain = S.Reals if symbol.is_real else S.Complexes
return solveset(simplify(1 / expression), symbol, domain)
###########################################################################
# DIFFERENTIAL CALCULUS METHODS #
###########################################################################
def monotonicity_helper(expression, predicate, interval=S.Reals, symbol=None):
"""
Helper function for functions checking function monotonicity.
Parameters
==========
expression : Expr
The target function which is being checked
predicate : function
The property being tested for. The function takes in an integer
and returns a boolean. The integer input is the derivative and
the boolean result should be true if the property is being held,
and false otherwise.
interval : Set, optional
The range of values in which we are testing, defaults to all reals.
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
It returns a boolean indicating whether the interval in which
the function's derivative satisfies given predicate is a superset
of the given interval.
Returns
=======
Boolean
True if ``predicate`` is true for all the derivatives when ``symbol``
is varied in ``range``, False otherwise.
"""
expression = sympify(expression)
free = expression.free_symbols
if symbol is None:
if len(free) > 1:
raise NotImplementedError(
'The function has not yet been implemented'
' for all multivariate expressions.'
)
variable = symbol or (free.pop() if free else Symbol('x'))
derivative = expression.diff(variable)
predicate_interval = solveset(predicate(derivative), variable, S.Reals)
return interval.is_subset(predicate_interval)
def is_increasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is increasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is increasing (either strictly increasing or
constant) in the given ``interval``, False otherwise.
Examples
========
>>> from sympy import is_increasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_increasing(x**3 - 3*x**2 + 4*x, S.Reals)
True
>>> is_increasing(-x**2, Interval(-oo, 0))
True
>>> is_increasing(-x**2, Interval(0, oo))
False
>>> is_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval(-2, 3))
False
>>> is_increasing(x**2 + y, Interval(1, 2), x)
True
"""
return monotonicity_helper(expression, lambda x: x >= 0, interval, symbol)
def is_strictly_increasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is strictly increasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is strictly increasing in the given ``interval``,
False otherwise.
Examples
========
>>> from sympy import is_strictly_increasing
>>> from sympy.abc import x, y
>>> from sympy import Interval, oo
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.Ropen(-oo, -2))
True
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.Lopen(3, oo))
True
>>> is_strictly_increasing(4*x**3 - 6*x**2 - 72*x + 30, Interval.open(-2, 3))
False
>>> is_strictly_increasing(-x**2, Interval(0, oo))
False
>>> is_strictly_increasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x > 0, interval, symbol)
def is_decreasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is decreasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is decreasing (either strictly decreasing or
constant) in the given ``interval``, False otherwise.
Examples
========
>>> from sympy import is_decreasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_decreasing(1/(x**2 - 3*x), Interval.open(1.5, 3))
True
>>> is_decreasing(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, S(3)/2))
False
>>> is_decreasing(-x**2, Interval(-oo, 0))
False
>>> is_decreasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x <= 0, interval, symbol)
def is_strictly_decreasing(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is strictly decreasing in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is strictly decreasing in the given ``interval``,
False otherwise.
Examples
========
>>> from sympy import is_strictly_decreasing
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_strictly_decreasing(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_strictly_decreasing(1/(x**2 - 3*x), Interval.Ropen(-oo, S(3)/2))
False
>>> is_strictly_decreasing(-x**2, Interval(-oo, 0))
False
>>> is_strictly_decreasing(-x**2 + y, Interval(-oo, 0), x)
False
"""
return monotonicity_helper(expression, lambda x: x < 0, interval, symbol)
def is_monotonic(expression, interval=S.Reals, symbol=None):
"""
Return whether the function is monotonic in the given interval.
Parameters
==========
expression : Expr
The target function which is being checked.
interval : Set, optional
The range of values in which we are testing (defaults to set of
all real numbers).
symbol : Symbol, optional
The symbol present in expression which gets varied over the given range.
Returns
=======
Boolean
True if ``expression`` is monotonic in the given ``interval``,
False otherwise.
Raises
======
NotImplementedError
Monotonicity check has not been implemented for the queried function.
Examples
========
>>> from sympy import is_monotonic
>>> from sympy.abc import x, y
>>> from sympy import S, Interval, oo
>>> is_monotonic(1/(x**2 - 3*x), Interval.open(1.5, 3))
True
>>> is_monotonic(1/(x**2 - 3*x), Interval.Lopen(3, oo))
True
>>> is_monotonic(x**3 - 3*x**2 + 4*x, S.Reals)
True
>>> is_monotonic(-x**2, S.Reals)
False
>>> is_monotonic(x**2 + y + 1, Interval(1, 2), x)
True
"""
expression = sympify(expression)
free = expression.free_symbols
if symbol is None and len(free) > 1:
raise NotImplementedError(
'is_monotonic has not yet been implemented'
' for all multivariate expressions.'
)
variable = symbol or (free.pop() if free else Symbol('x'))
turning_points = solveset(expression.diff(variable), variable, interval)
return interval.intersection(turning_points) is S.EmptySet
|
9111f104dc32d31b762b0075f809c5dcb06ea2d605d88283bde2a0e882a1d8aa
|
from sympy import Order, S, log, limit, lcm_list, pi, Abs
from sympy.core.basic import Basic
from sympy.core import Add, Mul, Pow
from sympy.logic.boolalg import And
from sympy.core.expr import AtomicExpr, Expr
from sympy.core.numbers import _sympifyit, oo
from sympy.core.sympify import _sympify
from sympy.sets.sets import (Interval, Intersection, FiniteSet, Union,
Complement, EmptySet)
from sympy.sets.conditionset import ConditionSet
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.utilities import filldedent
from sympy.simplify.radsimp import denom
from sympy.polys.rationaltools import together
from sympy.core.compatibility import iterable
def continuous_domain(f, symbol, domain):
"""
Returns the intervals in the given domain for which the function
is continuous.
This method is limited by the ability to determine the various
singularities and discontinuities of the given function.
Parameters
==========
f : Expr
The concerned function.
symbol : Symbol
The variable for which the intervals are to be determined.
domain : Interval
The domain over which the continuity of the symbol has to be checked.
Examples
========
>>> from sympy import Symbol, S, tan, log, pi, sqrt
>>> from sympy.sets import Interval
>>> from sympy.calculus.util import continuous_domain
>>> x = Symbol('x')
>>> continuous_domain(1/x, x, S.Reals)
Union(Interval.open(-oo, 0), Interval.open(0, oo))
>>> continuous_domain(tan(x), x, Interval(0, pi))
Union(Interval.Ropen(0, pi/2), Interval.Lopen(pi/2, pi))
>>> continuous_domain(sqrt(x - 2), x, Interval(-5, 5))
Interval(2, 5)
>>> continuous_domain(log(2*x - 1), x, S.Reals)
Interval.open(1/2, oo)
Returns
=======
Interval
Union of all intervals where the function is continuous.
Raises
======
NotImplementedError
If the method to determine continuity of such a function
has not yet been developed.
"""
from sympy.solvers.inequalities import solve_univariate_inequality
from sympy.solvers.solveset import solveset, _has_rational_power
if domain.is_subset(S.Reals):
constrained_interval = domain
for atom in f.atoms(Pow):
predicate, denomin = _has_rational_power(atom, symbol)
constraint = S.EmptySet
if predicate and denomin == 2:
constraint = solve_univariate_inequality(atom.base >= 0,
symbol).as_set()
constrained_interval = Intersection(constraint,
constrained_interval)
for atom in f.atoms(log):
constraint = solve_univariate_inequality(atom.args[0] > 0,
symbol).as_set()
constrained_interval = Intersection(constraint,
constrained_interval)
domain = constrained_interval
try:
sings = S.EmptySet
if f.has(Abs):
sings = solveset(1/f, symbol, domain) + \
solveset(denom(together(f)), symbol, domain)
else:
for atom in f.atoms(Pow):
predicate, denomin = _has_rational_power(atom, symbol)
if predicate and denomin == 2:
sings = solveset(1/f, symbol, domain) +\
solveset(denom(together(f)), symbol, domain)
break
else:
sings = Intersection(solveset(1/f, symbol), domain) + \
solveset(denom(together(f)), symbol, domain)
except NotImplementedError:
import sys
raise (NotImplementedError("Methods for determining the continuous domains"
" of this function have not been developed."),
None,
sys.exc_info()[2])
return domain - sings
def function_range(f, symbol, domain):
"""
Finds the range of a function in a given domain.
This method is limited by the ability to determine the singularities and
determine limits.
Examples
========
>>> from sympy import Symbol, S, exp, log, pi, sqrt, sin, tan
>>> from sympy.sets import Interval
>>> from sympy.calculus.util import function_range
>>> x = Symbol('x')
>>> function_range(sin(x), x, Interval(0, 2*pi))
Interval(-1, 1)
>>> function_range(tan(x), x, Interval(-pi/2, pi/2))
Interval(-oo, oo)
>>> function_range(1/x, x, S.Reals)
Union(Interval.open(-oo, 0), Interval.open(0, oo))
>>> function_range(exp(x), x, S.Reals)
Interval.open(0, oo)
>>> function_range(log(x), x, S.Reals)
Interval(-oo, oo)
>>> function_range(sqrt(x), x , Interval(-5, 9))
Interval(0, 3)
"""
from sympy.solvers.solveset import solveset
if isinstance(domain, EmptySet):
return S.EmptySet
period = periodicity(f, symbol)
if period is S.Zero:
# the expression is constant wrt symbol
return FiniteSet(f.expand())
if period is not None:
if isinstance(domain, Interval):
if (domain.inf - domain.sup).is_infinite:
domain = Interval(0, period)
elif isinstance(domain, Union):
for sub_dom in domain.args:
if isinstance(sub_dom, Interval) and \
((sub_dom.inf - sub_dom.sup).is_infinite):
domain = Interval(0, period)
intervals = continuous_domain(f, symbol, domain)
range_int = S.EmptySet
if isinstance(intervals,(Interval, FiniteSet)):
interval_iter = (intervals,)
elif isinstance(intervals, Union):
interval_iter = intervals.args
else:
raise NotImplementedError(filldedent('''
Unable to find range for the given domain.
'''))
for interval in interval_iter:
if isinstance(interval, FiniteSet):
for singleton in interval:
if singleton in domain:
range_int += FiniteSet(f.subs(symbol, singleton))
elif isinstance(interval, Interval):
vals = S.EmptySet
critical_points = S.EmptySet
critical_values = S.EmptySet
bounds = ((interval.left_open, interval.inf, '+'),
(interval.right_open, interval.sup, '-'))
for is_open, limit_point, direction in bounds:
if is_open:
critical_values += FiniteSet(limit(f, symbol, limit_point, direction))
vals += critical_values
else:
vals += FiniteSet(f.subs(symbol, limit_point))
solution = solveset(f.diff(symbol), symbol, interval)
if not iterable(solution):
raise NotImplementedError('Unable to find critical points for {}'.format(f))
critical_points += solution
for critical_point in critical_points:
vals += FiniteSet(f.subs(symbol, critical_point))
left_open, right_open = False, False
if critical_values is not S.EmptySet:
if critical_values.inf == vals.inf:
left_open = True
if critical_values.sup == vals.sup:
right_open = True
range_int += Interval(vals.inf, vals.sup, left_open, right_open)
else:
raise NotImplementedError(filldedent('''
Unable to find range for the given domain.
'''))
return range_int
def not_empty_in(finset_intersection, *syms):
""" Finds the domain of the functions in `finite_set` in which the
`finite_set` is not-empty
Parameters
==========
finset_intersection: The unevaluated intersection of FiniteSet containing
real-valued functions with Union of Sets
syms: Tuple of symbols
Symbol for which domain is to be found
Raises
======
NotImplementedError
The algorithms to find the non-emptiness of the given FiniteSet are
not yet implemented.
ValueError
The input is not valid.
RuntimeError
It is a bug, please report it to the github issue tracker
(https://github.com/sympy/sympy/issues).
Examples
========
>>> from sympy import FiniteSet, Interval, not_empty_in, oo
>>> from sympy.abc import x
>>> not_empty_in(FiniteSet(x/2).intersect(Interval(0, 1)), x)
Interval(0, 2)
>>> not_empty_in(FiniteSet(x, x**2).intersect(Interval(1, 2)), x)
Union(Interval(-sqrt(2), -1), Interval(1, 2))
>>> not_empty_in(FiniteSet(x**2/(x + 2)).intersect(Interval(1, oo)), x)
Union(Interval.Lopen(-2, -1), Interval(2, oo))
"""
# TODO: handle piecewise defined functions
# TODO: handle transcendental functions
# TODO: handle multivariate functions
if len(syms) == 0:
raise ValueError("One or more symbols must be given in syms.")
if finset_intersection.is_EmptySet:
return EmptySet()
if isinstance(finset_intersection, Union):
elm_in_sets = finset_intersection.args[0]
return Union(not_empty_in(finset_intersection.args[1], *syms),
elm_in_sets)
if isinstance(finset_intersection, FiniteSet):
finite_set = finset_intersection
_sets = S.Reals
else:
finite_set = finset_intersection.args[1]
_sets = finset_intersection.args[0]
if not isinstance(finite_set, FiniteSet):
raise ValueError('A FiniteSet must be given, not %s: %s' %
(type(finite_set), finite_set))
if len(syms) == 1:
symb = syms[0]
else:
raise NotImplementedError('more than one variables %s not handled' %
(syms,))
def elm_domain(expr, intrvl):
""" Finds the domain of an expression in any given interval """
from sympy.solvers.solveset import solveset
_start = intrvl.start
_end = intrvl.end
_singularities = solveset(expr.as_numer_denom()[1], symb,
domain=S.Reals)
if intrvl.right_open:
if _end is S.Infinity:
_domain1 = S.Reals
else:
_domain1 = solveset(expr < _end, symb, domain=S.Reals)
else:
_domain1 = solveset(expr <= _end, symb, domain=S.Reals)
if intrvl.left_open:
if _start is S.NegativeInfinity:
_domain2 = S.Reals
else:
_domain2 = solveset(expr > _start, symb, domain=S.Reals)
else:
_domain2 = solveset(expr >= _start, symb, domain=S.Reals)
# domain in the interval
expr_with_sing = Intersection(_domain1, _domain2)
expr_domain = Complement(expr_with_sing, _singularities)
return expr_domain
if isinstance(_sets, Interval):
return Union(*[elm_domain(element, _sets) for element in finite_set])
if isinstance(_sets, Union):
_domain = S.EmptySet
for intrvl in _sets.args:
_domain_element = Union(*[elm_domain(element, intrvl)
for element in finite_set])
_domain = Union(_domain, _domain_element)
return _domain
def periodicity(f, symbol, check=False):
"""
Tests the given function for periodicity in the given symbol.
Parameters
==========
f : Expr.
The concerned function.
symbol : Symbol
The variable for which the period is to be determined.
check : Boolean
The flag to verify whether the value being returned is a period or not.
Returns
=======
period
The period of the function is returned.
`None` is returned when the function is aperiodic or has a complex period.
The value of `0` is returned as the period of a constant function.
Raises
======
NotImplementedError
The value of the period computed cannot be verified.
Notes
=====
Currently, we do not support functions with a complex period.
The period of functions having complex periodic values such
as `exp`, `sinh` is evaluated to `None`.
The value returned might not be the "fundamental" period of the given
function i.e. it may not be the smallest periodic value of the function.
The verification of the period through the `check` flag is not reliable
due to internal simplification of the given expression. Hence, it is set
to `False` by default.
Examples
========
>>> from sympy import Symbol, sin, cos, tan, exp
>>> from sympy.calculus.util import periodicity
>>> x = Symbol('x')
>>> f = sin(x) + sin(2*x) + sin(3*x)
>>> periodicity(f, x)
2*pi
>>> periodicity(sin(x)*cos(x), x)
pi
>>> periodicity(exp(tan(2*x) - 1), x)
pi/2
>>> periodicity(sin(4*x)**cos(2*x), x)
pi
>>> periodicity(exp(x), x)
"""
from sympy.core.function import diff
from sympy.core.mod import Mod
from sympy.core.relational import Relational
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.trigonometric import (
TrigonometricFunction, sin, cos, csc, sec)
from sympy.simplify.simplify import simplify
from sympy.solvers.decompogen import decompogen
from sympy.polys.polytools import degree, lcm_list
def _check(orig_f, period):
'''Return the checked period or raise an error.'''
new_f = orig_f.subs(symbol, symbol + period)
if new_f.equals(orig_f):
return period
else:
raise NotImplementedError(filldedent('''
The period of the given function cannot be verified.
When `%s` was replaced with `%s + %s` in `%s`, the result
was `%s` which was not recognized as being the same as
the original function.
So either the period was wrong or the two forms were
not recognized as being equal.
Set check=False to obtain the value.''' %
(symbol, symbol, period, orig_f, new_f)))
orig_f = f
period = None
if isinstance(f, Relational):
f = f.lhs - f.rhs
f = simplify(f)
if symbol not in f.free_symbols:
return S.Zero
if isinstance(f, TrigonometricFunction):
try:
period = f.period(symbol)
except NotImplementedError:
pass
if isinstance(f, Abs):
arg = f.args[0]
if isinstance(arg, (sec, csc, cos)):
# all but tan and cot might have a
# a period that is half as large
# so recast as sin
arg = sin(arg.args[0])
period = periodicity(arg, symbol)
if period is not None and isinstance(arg, sin):
# the argument of Abs was a trigonometric other than
# cot or tan; test to see if the half-period
# is valid. Abs(arg) has behaviour equivalent to
# orig_f, so use that for test:
orig_f = Abs(arg)
try:
return _check(orig_f, period/2)
except NotImplementedError as err:
if check:
raise NotImplementedError(err)
# else let new orig_f and period be
# checked below
if f.is_Pow:
base, expo = f.args
base_has_sym = base.has(symbol)
expo_has_sym = expo.has(symbol)
if base_has_sym and not expo_has_sym:
period = periodicity(base, symbol)
elif expo_has_sym and not base_has_sym:
period = periodicity(expo, symbol)
else:
period = _periodicity(f.args, symbol)
elif f.is_Mul:
coeff, g = f.as_independent(symbol, as_Add=False)
if isinstance(g, TrigonometricFunction) or coeff is not S.One:
period = periodicity(g, symbol)
else:
period = _periodicity(g.args, symbol)
elif f.is_Add:
k, g = f.as_independent(symbol)
if k is not S.Zero:
return periodicity(g, symbol)
period = _periodicity(g.args, symbol)
elif isinstance(f, Mod):
a, n = f.args
if a == symbol:
period = n
elif isinstance(a, TrigonometricFunction):
period = periodicity(a, symbol)
#check if 'f' is linear in 'symbol'
elif (a.is_polynomial(symbol) and degree(a, symbol) == 1 and
symbol not in n.free_symbols):
period = Abs(n / a.diff(symbol))
elif period is None:
from sympy.solvers.decompogen import compogen
g_s = decompogen(f, symbol)
num_of_gs = len(g_s)
if num_of_gs > 1:
for index, g in enumerate(reversed(g_s)):
start_index = num_of_gs - 1 - index
g = compogen(g_s[start_index:], symbol)
if g != orig_f and g != f: # Fix for issue 12620
period = periodicity(g, symbol)
if period is not None:
break
if period is not None:
if check:
return _check(orig_f, period)
return period
return None
def _periodicity(args, symbol):
"""Helper for periodicity to find the period of a list of simpler
functions. It uses the `lcim` method to find the least common period of
all the functions.
"""
periods = []
for f in args:
period = periodicity(f, symbol)
if period is None:
return None
if period is not S.Zero:
periods.append(period)
if len(periods) > 1:
return lcim(periods)
return periods[0]
def lcim(numbers):
"""Returns the least common integral multiple of a list of numbers.
The numbers can be rational or irrational or a mixture of both.
`None` is returned for incommensurable numbers.
Examples
========
>>> from sympy import S, pi
>>> from sympy.calculus.util import lcim
>>> lcim([S(1)/2, S(3)/4, S(5)/6])
15/2
>>> lcim([2*pi, 3*pi, pi, pi/2])
6*pi
>>> lcim([S(1), 2*pi])
"""
result = None
if all(num.is_irrational for num in numbers):
factorized_nums = list(map(lambda num: num.factor(), numbers))
factors_num = list(
map(lambda num: num.as_coeff_Mul(),
factorized_nums))
term = factors_num[0][1]
if all(factor == term for coeff, factor in factors_num):
common_term = term
coeffs = [coeff for coeff, factor in factors_num]
result = lcm_list(coeffs) * common_term
elif all(num.is_rational for num in numbers):
result = lcm_list(numbers)
else:
pass
return result
class AccumulationBounds(AtomicExpr):
r"""
# Note AccumulationBounds has an alias: AccumBounds
AccumulationBounds represent an interval `[a, b]`, which is always closed
at the ends. Here `a` and `b` can be any value from extended real numbers.
The intended meaning of AccummulationBounds is to give an approximate
location of the accumulation points of a real function at a limit point.
Let `a` and `b` be reals such that a <= b.
`\langle a, b\rangle = \{x \in \mathbb{R} \mid a \le x \le b\}`
`\langle -\infty, b\rangle = \{x \in \mathbb{R} \mid x \le b\} \cup \{-\infty, \infty\}`
`\langle a, \infty \rangle = \{x \in \mathbb{R} \mid a \le x\} \cup \{-\infty, \infty\}`
`\langle -\infty, \infty \rangle = \mathbb{R} \cup \{-\infty, \infty\}`
`oo` and `-oo` are added to the second and third definition respectively,
since if either `-oo` or `oo` is an argument, then the other one should
be included (though not as an end point). This is forced, since we have,
for example, `1/AccumBounds(0, 1) = AccumBounds(1, oo)`, and the limit at
`0` is not one-sided. As x tends to `0-`, then `1/x -> -oo`, so `-oo`
should be interpreted as belonging to `AccumBounds(1, oo)` though it need
not appear explicitly.
In many cases it suffices to know that the limit set is bounded.
However, in some other cases more exact information could be useful.
For example, all accumulation values of cos(x) + 1 are non-negative.
(AccumBounds(-1, 1) + 1 = AccumBounds(0, 2))
A AccumulationBounds object is defined to be real AccumulationBounds,
if its end points are finite reals.
Let `X`, `Y` be real AccumulationBounds, then their sum, difference,
product are defined to be the following sets:
`X + Y = \{ x+y \mid x \in X \cap y \in Y\}`
`X - Y = \{ x-y \mid x \in X \cap y \in Y\}`
`X * Y = \{ x*y \mid x \in X \cap y \in Y\}`
There is, however, no consensus on Interval division.
`X / Y = \{ z \mid \exists x \in X, y \in Y \mid y \neq 0, z = x/y\}`
Note: According to this definition the quotient of two AccumulationBounds
may not be a AccumulationBounds object but rather a union of
AccumulationBounds.
Note
====
The main focus in the interval arithmetic is on the simplest way to
calculate upper and lower endpoints for the range of values of a
function in one or more variables. These barriers are not necessarily
the supremum or infimum, since the precise calculation of those values
can be difficult or impossible.
Examples
========
>>> from sympy import AccumBounds, sin, exp, log, pi, E, S, oo
>>> from sympy.abc import x
>>> AccumBounds(0, 1) + AccumBounds(1, 2)
AccumBounds(1, 3)
>>> AccumBounds(0, 1) - AccumBounds(0, 2)
AccumBounds(-2, 1)
>>> AccumBounds(-2, 3)*AccumBounds(-1, 1)
AccumBounds(-3, 3)
>>> AccumBounds(1, 2)*AccumBounds(3, 5)
AccumBounds(3, 10)
The exponentiation of AccumulationBounds is defined
as follows:
If 0 does not belong to `X` or `n > 0` then
`X^n = \{ x^n \mid x \in X\}`
otherwise
`X^n = \{ x^n \mid x \neq 0, x \in X\} \cup \{-\infty, \infty\}`
Here for fractional `n`, the part of `X` resulting in a complex
AccumulationBounds object is neglected.
>>> AccumBounds(-1, 4)**(S(1)/2)
AccumBounds(0, 2)
>>> AccumBounds(1, 2)**2
AccumBounds(1, 4)
>>> AccumBounds(-1, oo)**(-1)
AccumBounds(-oo, oo)
Note: `<a, b>^2` is not same as `<a, b>*<a, b>`
>>> AccumBounds(-1, 1)**2
AccumBounds(0, 1)
>>> AccumBounds(1, 3) < 4
True
>>> AccumBounds(1, 3) < -1
False
Some elementary functions can also take AccumulationBounds as input.
A function `f` evaluated for some real AccumulationBounds `<a, b>`
is defined as `f(\langle a, b\rangle) = \{ f(x) \mid a \le x \le b \}`
>>> sin(AccumBounds(pi/6, pi/3))
AccumBounds(1/2, sqrt(3)/2)
>>> exp(AccumBounds(0, 1))
AccumBounds(1, E)
>>> log(AccumBounds(1, E))
AccumBounds(0, 1)
Some symbol in an expression can be substituted for a AccumulationBounds
object. But it doesn't necessarily evaluate the AccumulationBounds for
that expression.
Same expression can be evaluated to different values depending upon
the form it is used for substitution. For example:
>>> (x**2 + 2*x + 1).subs(x, AccumBounds(-1, 1))
AccumBounds(-1, 4)
>>> ((x + 1)**2).subs(x, AccumBounds(-1, 1))
AccumBounds(0, 4)
References
==========
.. [1] https://en.wikipedia.org/wiki/Interval_arithmetic
.. [2] http://fab.cba.mit.edu/classes/S62.12/docs/Hickey_interval.pdf
Notes
=====
Do not use ``AccumulationBounds`` for floating point interval arithmetic
calculations, use ``mpmath.iv`` instead.
"""
is_real = True
def __new__(cls, min, max):
min = _sympify(min)
max = _sympify(max)
inftys = [S.Infinity, S.NegativeInfinity]
# Only allow real intervals (use symbols with 'is_real=True').
if not (min.is_real or min in inftys) \
or not (max.is_real or max in inftys):
raise ValueError("Only real AccumulationBounds are supported")
# Make sure that the created AccumBounds object will be valid.
if max.is_comparable and min.is_comparable:
if max < min:
raise ValueError(
"Lower limit should be smaller than upper limit")
if max == min:
return max
return Basic.__new__(cls, min, max)
# setting the operation priority
_op_priority = 11.0
@property
def min(self):
"""
Returns the minimum possible value attained by AccumulationBounds
object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).min
1
"""
return self.args[0]
@property
def max(self):
"""
Returns the maximum possible value attained by AccumulationBounds
object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).max
3
"""
return self.args[1]
@property
def delta(self):
"""
Returns the difference of maximum possible value attained by
AccumulationBounds object and minimum possible value attained
by AccumulationBounds object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).delta
2
"""
return self.max - self.min
@property
def mid(self):
"""
Returns the mean of maximum possible value attained by
AccumulationBounds object and minimum possible value
attained by AccumulationBounds object.
Examples
========
>>> from sympy import AccumBounds
>>> AccumBounds(1, 3).mid
2
"""
return (self.min + self.max) / 2
@_sympifyit('other', NotImplemented)
def _eval_power(self, other):
return self.__pow__(other)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(
Add(self.min, other.min),
Add(self.max, other.max))
if other is S.Infinity and self.min is S.NegativeInfinity or \
other is S.NegativeInfinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif other.is_real:
return AccumBounds(Add(self.min, other), Add(self.max, other))
return Add(self, other, evaluate=False)
return NotImplemented
__radd__ = __add__
def __neg__(self):
return AccumBounds(-self.max, -self.min)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(
Add(self.min, -other.max),
Add(self.max, -other.min))
if other is S.NegativeInfinity and self.min is S.NegativeInfinity or \
other is S.Infinity and self.max is S.Infinity:
return AccumBounds(-oo, oo)
elif other.is_real:
return AccumBounds(
Add(self.min, -other),
Add(self.max, -other))
return Add(self, -other, evaluate=False)
return NotImplemented
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
return self.__neg__() + other
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
return AccumBounds(Min(Mul(self.min, other.min),
Mul(self.min, other.max),
Mul(self.max, other.min),
Mul(self.max, other.max)),
Max(Mul(self.min, other.min),
Mul(self.min, other.max),
Mul(self.max, other.min),
Mul(self.max, other.max)))
if other is S.Infinity:
if self.min.is_zero:
return AccumBounds(0, oo)
if self.max.is_zero:
return AccumBounds(-oo, 0)
if other is S.NegativeInfinity:
if self.min.is_zero:
return AccumBounds(-oo, 0)
if self.max.is_zero:
return AccumBounds(0, oo)
if other.is_real:
if other.is_zero:
if self == AccumBounds(-oo, oo):
return AccumBounds(-oo, oo)
if self.max is S.Infinity:
return AccumBounds(0, oo)
if self.min is S.NegativeInfinity:
return AccumBounds(-oo, 0)
return S.Zero
if other.is_positive:
return AccumBounds(
Mul(self.min, other),
Mul(self.max, other))
elif other.is_negative:
return AccumBounds(
Mul(self.max, other),
Mul(self.min, other))
if isinstance(other, Order):
return other
return Mul(self, other, evaluate=False)
return NotImplemented
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if isinstance(other, Expr):
if isinstance(other, AccumBounds):
if S.Zero not in other:
return self * AccumBounds(1/other.max, 1/other.min)
if S.Zero in self and S.Zero in other:
if self.min.is_zero and other.min.is_zero:
return AccumBounds(0, oo)
if self.max.is_zero and other.min.is_zero:
return AccumBounds(-oo, 0)
return AccumBounds(-oo, oo)
if self.max.is_negative:
if other.min.is_negative:
if other.max.is_zero:
return AccumBounds(self.max / other.min, oo)
if other.max.is_positive:
# the actual answer is a Union of AccumBounds,
# Union(AccumBounds(-oo, self.max/other.max),
# AccumBounds(self.max/other.min, oo))
return AccumBounds(-oo, oo)
if other.min.is_zero and other.max.is_positive:
return AccumBounds(-oo, self.max / other.max)
if self.min.is_positive:
if other.min.is_negative:
if other.max.is_zero:
return AccumBounds(-oo, self.min / other.min)
if other.max.is_positive:
# the actual answer is a Union of AccumBounds,
# Union(AccumBounds(-oo, self.min/other.min),
# AccumBounds(self.min/other.max, oo))
return AccumBounds(-oo, oo)
if other.min.is_zero and other.max.is_positive:
return AccumBounds(self.min / other.max, oo)
elif other.is_real:
if other is S.Infinity or other is S.NegativeInfinity:
if self == AccumBounds(-oo, oo):
return AccumBounds(-oo, oo)
if self.max is S.Infinity:
return AccumBounds(Min(0, other), Max(0, other))
if self.min is S.NegativeInfinity:
return AccumBounds(Min(0, -other), Max(0, -other))
if other.is_positive:
return AccumBounds(self.min / other, self.max / other)
elif other.is_negative:
return AccumBounds(self.max / other, self.min / other)
return Mul(self, 1 / other, evaluate=False)
return NotImplemented
__truediv__ = __div__
@_sympifyit('other', NotImplemented)
def __rdiv__(self, other):
if isinstance(other, Expr):
if other.is_real:
if other.is_zero:
return S.Zero
if S.Zero in self:
if self.min == S.Zero:
if other.is_positive:
return AccumBounds(Mul(other, 1 / self.max), oo)
if other.is_negative:
return AccumBounds(-oo, Mul(other, 1 / self.max))
if self.max == S.Zero:
if other.is_positive:
return AccumBounds(-oo, Mul(other, 1 / self.min))
if other.is_negative:
return AccumBounds(Mul(other, 1 / self.min), oo)
return AccumBounds(-oo, oo)
else:
return AccumBounds(Min(other / self.min, other / self.max),
Max(other / self.min, other / self.max))
return Mul(other, 1 / self, evaluate=False)
else:
return NotImplemented
__rtruediv__ = __rdiv__
@_sympifyit('other', NotImplemented)
def __pow__(self, other):
from sympy.functions.elementary.miscellaneous import real_root
if isinstance(other, Expr):
if other is S.Infinity:
if self.min.is_nonnegative:
if self.max < 1:
return S.Zero
if self.min > 1:
return S.Infinity
return AccumBounds(0, oo)
elif self.max.is_negative:
if self.min > -1:
return S.Zero
if self.max < -1:
return FiniteSet(-oo, oo)
return AccumBounds(-oo, oo)
else:
if self.min > -1:
if self.max < 1:
return S.Zero
return AccumBounds(0, oo)
return AccumBounds(-oo, oo)
if other is S.NegativeInfinity:
return (1 / self)**oo
if other.is_real and other.is_number:
if other.is_zero:
return S.One
if other.is_Integer:
if self.min.is_positive:
return AccumBounds(
Min(self.min ** other, self.max ** other),
Max(self.min ** other, self.max ** other))
elif self.max.is_negative:
return AccumBounds(
Min(self.max ** other, self.min ** other),
Max(self.max ** other, self.min ** other))
if other % 2 == 0:
if other.is_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(self.min**other, oo)
return AccumBounds(0, oo)
return AccumBounds(
S.Zero, Max(self.min**other, self.max**other))
else:
if other.is_negative:
if self.min.is_zero:
return AccumBounds(self.max**other, oo)
if self.max.is_zero:
return AccumBounds(-oo, self.min**other)
return AccumBounds(-oo, oo)
return AccumBounds(self.min**other, self.max**other)
num, den = other.as_numer_denom()
if num == S(1):
if den % 2 == 0:
if S.Zero in self:
if self.min.is_negative:
return AccumBounds(0, real_root(self.max, den))
return AccumBounds(real_root(self.min, den),
real_root(self.max, den))
num_pow = self**num
return num_pow**(1 / den)
return Pow(self, other, evaluate=False)
return NotImplemented
def __abs__(self):
if self.max.is_negative:
return self.__neg__()
elif self.min.is_negative:
return AccumBounds(S.Zero, Max(abs(self.min), self.max))
else:
return self
def __lt__(self, other):
"""
Returns True if range of values attained by `self` AccumulationBounds
object is less than the range of values attained by `other`, where
other may be any value of type AccumulationBounds object or extended
real number value, False if `other` satisfies the same property, else
an unevaluated Relational
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) < AccumBounds(4, oo)
True
>>> AccumBounds(1, 4) < AccumBounds(3, 4)
AccumBounds(1, 4) < AccumBounds(3, 4)
>>> AccumBounds(1, oo) < -1
False
"""
other = _sympify(other)
if isinstance(other, AccumBounds):
if self.max < other.min:
return True
if self.min >= other.max:
return False
elif not(other.is_real or other is S.Infinity or
other is S.NegativeInfinity):
raise TypeError(
"Invalid comparison of %s %s" %
(type(other), other))
elif other.is_comparable:
if self.max < other:
return True
if self.min >= other:
return False
return super(AccumulationBounds, self).__lt__(other)
def __le__(self, other):
"""
Returns True if range of values attained by `self` AccumulationBounds
object is less than or equal to the range of values attained by
`other`, where other may be any value of type AccumulationBounds
object or extended real number value, False if `other`
satisfies the same property, else an unevaluated Relational.
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) <= AccumBounds(4, oo)
True
>>> AccumBounds(1, 4) <= AccumBounds(3, 4)
AccumBounds(1, 4) <= AccumBounds(3, 4)
>>> AccumBounds(1, 3) <= 0
False
"""
other = _sympify(other)
if isinstance(other, AccumBounds):
if self.max <= other.min:
return True
if self.min > other.max:
return False
elif not(other.is_real or other is S.Infinity or
other is S.NegativeInfinity):
raise TypeError(
"Invalid comparison of %s %s" %
(type(other), other))
elif other.is_comparable:
if self.max <= other:
return True
if self.min > other:
return False
return super(AccumulationBounds, self).__le__(other)
def __gt__(self, other):
"""
Returns True if range of values attained by `self` AccumulationBounds
object is greater than the range of values attained by `other`,
where other may be any value of type AccumulationBounds object or
extended real number value, False if `other` satisfies
the same property, else an unevaluated Relational.
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) > AccumBounds(4, oo)
False
>>> AccumBounds(1, 4) > AccumBounds(3, 4)
AccumBounds(1, 4) > AccumBounds(3, 4)
>>> AccumBounds(1, oo) > -1
True
"""
other = _sympify(other)
if isinstance(other, AccumBounds):
if self.min > other.max:
return True
if self.max <= other.min:
return False
elif not(other.is_real or other is S.Infinity or
other is S.NegativeInfinity):
raise TypeError(
"Invalid comparison of %s %s" %
(type(other), other))
elif other.is_comparable:
if self.min > other:
return True
if self.max <= other:
return False
return super(AccumulationBounds, self).__gt__(other)
def __ge__(self, other):
"""
Returns True if range of values attained by `self` AccumulationBounds
object is less that the range of values attained by `other`, where
other may be any value of type AccumulationBounds object or extended
real number value, False if `other` satisfies the same
property, else an unevaluated Relational.
Examples
========
>>> from sympy import AccumBounds, oo
>>> AccumBounds(1, 3) >= AccumBounds(4, oo)
False
>>> AccumBounds(1, 4) >= AccumBounds(3, 4)
AccumBounds(1, 4) >= AccumBounds(3, 4)
>>> AccumBounds(1, oo) >= 1
True
"""
other = _sympify(other)
if isinstance(other, AccumBounds):
if self.min >= other.max:
return True
if self.max < other.min:
return False
elif not(other.is_real or other is S.Infinity or
other is S.NegativeInfinity):
raise TypeError(
"Invalid comparison of %s %s" %
(type(other), other))
elif other.is_comparable:
if self.min >= other:
return True
if self.max < other:
return False
return super(AccumulationBounds, self).__ge__(other)
def __contains__(self, other):
"""
Returns True if other is contained in self, where other
belongs to extended real numbers, False if not contained,
otherwise TypeError is raised.
Examples
========
>>> from sympy import AccumBounds, oo
>>> 1 in AccumBounds(-1, 3)
True
-oo and oo go together as limits (in AccumulationBounds).
>>> -oo in AccumBounds(1, oo)
True
>>> oo in AccumBounds(-oo, 0)
True
"""
other = _sympify(other)
if other is S.Infinity or other is S.NegativeInfinity:
if self.min is S.NegativeInfinity or self.max is S.Infinity:
return True
return False
rv = And(self.min <= other, self.max >= other)
if rv not in (True, False):
raise TypeError("input failed to evaluate")
return rv
def intersection(self, other):
"""
Returns the intersection of 'self' and 'other'.
Here other can be an instance of FiniteSet or AccumulationBounds.
Examples
========
>>> from sympy import AccumBounds, FiniteSet
>>> AccumBounds(1, 3).intersection(AccumBounds(2, 4))
AccumBounds(2, 3)
>>> AccumBounds(1, 3).intersection(AccumBounds(4, 6))
EmptySet()
>>> AccumBounds(1, 4).intersection(FiniteSet(1, 2, 5))
{1, 2}
"""
if not isinstance(other, (AccumBounds, FiniteSet)):
raise TypeError(
"Input must be AccumulationBounds or FiniteSet object")
if isinstance(other, FiniteSet):
fin_set = S.EmptySet
for i in other:
if i in self:
fin_set = fin_set + FiniteSet(i)
return fin_set
if self.max < other.min or self.min > other.max:
return S.EmptySet
if self.min <= other.min:
if self.max <= other.max:
return AccumBounds(other.min, self.max)
if self.max > other.max:
return other
if other.min <= self.min:
if other.max < self.max:
return AccumBounds(self.min, other.max)
if other.max > self.max:
return self
def union(self, other):
# TODO : Devise a better method for Union of AccumBounds
# this method is not actually correct and
# can be made better
if not isinstance(other, AccumBounds):
raise TypeError(
"Input must be AccumulationBounds or FiniteSet object")
if self.min <= other.min and self.max >= other.min:
return AccumBounds(self.min, Max(self.max, other.max))
if other.min <= self.min and other.max >= self.min:
return AccumBounds(other.min, Max(self.max, other.max))
# setting an alias for AccumulationBounds
AccumBounds = AccumulationBounds
|
f305f69e4ca5fbcf48a89b51376bf8a551c44d74d8018c824b1ec8efc4726273
|
"""py.test hacks to support XFAIL/XPASS"""
from __future__ import print_function, division
import sys
import functools
import os
import contextlib
import warnings
from sympy.core.compatibility import get_function_name
from sympy.utilities.exceptions import SymPyDeprecationWarning
try:
import py
from _pytest.python_api import raises
from _pytest.recwarn import warns
from _pytest.outcomes import skip, Failed
USE_PYTEST = getattr(sys, '_running_pytest', False)
except ImportError:
USE_PYTEST = False
ON_TRAVIS = os.getenv('TRAVIS_BUILD_NUMBER', None)
if not USE_PYTEST:
def raises(expectedException, code=None):
"""
Tests that ``code`` raises the exception ``expectedException``.
``code`` may be a callable, such as a lambda expression or function
name.
If ``code`` is not given or None, ``raises`` will return a context
manager for use in ``with`` statements; the code to execute then
comes from the scope of the ``with``.
``raises()`` does nothing if the callable raises the expected exception,
otherwise it raises an AssertionError.
Examples
========
>>> from sympy.utilities.pytest import raises
>>> raises(ZeroDivisionError, lambda: 1/0)
>>> raises(ZeroDivisionError, lambda: 1/2)
Traceback (most recent call last):
...
Failed: DID NOT RAISE
>>> with raises(ZeroDivisionError):
... n = 1/0
>>> with raises(ZeroDivisionError):
... n = 1/2
Traceback (most recent call last):
...
Failed: DID NOT RAISE
Note that you cannot test multiple statements via
``with raises``:
>>> with raises(ZeroDivisionError):
... n = 1/0 # will execute and raise, aborting the ``with``
... n = 9999/0 # never executed
This is just what ``with`` is supposed to do: abort the
contained statement sequence at the first exception and let
the context manager deal with the exception.
To test multiple statements, you'll need a separate ``with``
for each:
>>> with raises(ZeroDivisionError):
... n = 1/0 # will execute and raise
>>> with raises(ZeroDivisionError):
... n = 9999/0 # will also execute and raise
"""
if code is None:
return RaisesContext(expectedException)
elif callable(code):
try:
code()
except expectedException:
return
raise Failed("DID NOT RAISE")
elif isinstance(code, str):
raise TypeError(
'\'raises(xxx, "code")\' has been phased out; '
'change \'raises(xxx, "expression")\' '
'to \'raises(xxx, lambda: expression)\', '
'\'raises(xxx, "statement")\' '
'to \'with raises(xxx): statement\'')
else:
raise TypeError(
'raises() expects a callable for the 2nd argument.')
class RaisesContext(object):
def __init__(self, expectedException):
self.expectedException = expectedException
def __enter__(self):
return None
def __exit__(self, exc_type, exc_value, traceback):
if exc_type is None:
raise Failed("DID NOT RAISE")
return issubclass(exc_type, self.expectedException)
class XFail(Exception):
pass
class XPass(Exception):
pass
class Skipped(Exception):
pass
class Failed(Exception):
pass
def XFAIL(func):
def wrapper():
try:
func()
except Exception as e:
message = str(e)
if message != "Timeout":
raise XFail(get_function_name(func))
else:
raise Skipped("Timeout")
raise XPass(get_function_name(func))
wrapper = functools.update_wrapper(wrapper, func)
return wrapper
def skip(str):
raise Skipped(str)
def SKIP(reason):
"""Similar to :func:`skip`, but this is a decorator. """
def wrapper(func):
def func_wrapper():
raise Skipped(reason)
func_wrapper = functools.update_wrapper(func_wrapper, func)
return func_wrapper
return wrapper
def slow(func):
func._slow = True
def func_wrapper():
func()
func_wrapper = functools.update_wrapper(func_wrapper, func)
func_wrapper.__wrapped__ = func
return func_wrapper
@contextlib.contextmanager
def warns(warningcls, **kwargs):
'''Like raises but tests that warnings are emitted.
>>> from sympy.utilities.pytest import warns
>>> import warnings
>>> with warns(UserWarning):
... warnings.warn('deprecated', UserWarning)
>>> with warns(UserWarning):
... pass
Traceback (most recent call last):
...
Failed: DID NOT WARN. No warnings of type UserWarning\
was emitted. The list of emitted warnings is: [].
'''
match = kwargs.pop('match', '')
if kwargs:
raise TypeError('Invalid keyword arguments: %s' % kwargs)
# Absorbs all warnings in warnrec
with warnings.catch_warnings(record=True) as warnrec:
# Hide all warnings but make sure that our warning is emitted
warnings.simplefilter("ignore")
warnings.filterwarnings("always", match, warningcls)
# Now run the test
yield
# Raise if expected warning not found
if not any(issubclass(w.category, warningcls) for w in warnrec):
msg = ('Failed: DID NOT WARN.'
' No warnings of type %s was emitted.'
' The list of emitted warnings is: %s.'
) % (warningcls, [w.message for w in warnrec])
raise Failed(msg)
else:
XFAIL = py.test.mark.xfail
slow = py.test.mark.slow
def SKIP(reason):
def skipping(func):
@functools.wraps(func)
def inner(*args, **kwargs):
skip(reason)
return inner
return skipping
@contextlib.contextmanager
def warns_deprecated_sympy():
'''Shorthand for ``warns(SymPyDeprecationWarning)``
This is the recommended way to test that ``SymPyDeprecationWarning`` is
emitted for deprecated features in SymPy. To test for other warnings use
``warns``. To suppress warnings without asserting that they are emitted
use ``ignore_warnings``.
>>> from sympy.utilities.pytest import warns_deprecated_sympy
>>> from sympy.utilities.exceptions import SymPyDeprecationWarning
>>> import warnings
>>> with warns_deprecated_sympy():
... SymPyDeprecationWarning("Don't use", feature="old thing",
... deprecated_since_version="1.0", issue=123).warn()
>>> with warns_deprecated_sympy():
... pass
Traceback (most recent call last):
...
Failed: DID NOT WARN. No warnings of type \
SymPyDeprecationWarning was emitted. The list of emitted warnings is: [].
'''
with warns(SymPyDeprecationWarning):
yield
@contextlib.contextmanager
def ignore_warnings(warningcls):
'''Context manager to suppress warnings during tests.
This function is useful for suppressing warnings during tests. The warns
function should be used to assert that a warning is raised. The
ignore_warnings function is useful in situation when the warning is not
guaranteed to be raised (e.g. on importing a module) or if the warning
comes from third-party code.
When the warning is coming (reliably) from SymPy the warns function should
be preferred to ignore_warnings.
>>> from sympy.utilities.pytest import ignore_warnings
>>> import warnings
Here's a warning:
>>> with warnings.catch_warnings(): # reset warnings in doctest
... warnings.simplefilter('error')
... warnings.warn('deprecated', UserWarning)
Traceback (most recent call last):
...
UserWarning: deprecated
Let's suppress it with ignore_warnings:
>>> with warnings.catch_warnings(): # reset warnings in doctest
... warnings.simplefilter('error')
... with ignore_warnings(UserWarning):
... warnings.warn('deprecated', UserWarning)
(No warning emitted)
'''
# Absorbs all warnings in warnrec
with warnings.catch_warnings(record=True) as warnrec:
# Make sure our warning doesn't get filtered
warnings.simplefilter("always", warningcls)
# Now run the test
yield
# Reissue any warnings that we aren't testing for
for w in warnrec:
if not issubclass(w.category, warningcls):
warnings.warn_explicit(w.message, w.category, w.filename, w.lineno)
|
c8f51609d6b9c53681b551afcddb6f9d806a653005a883943e6a91f7c6fd8908
|
"""
This module provides convenient functions to transform sympy expressions to
lambda functions which can be used to calculate numerical values very fast.
"""
from __future__ import print_function, division
from functools import wraps
import inspect
import keyword
import re
import textwrap
import linecache
from sympy.core.compatibility import (exec_, is_sequence, iterable,
NotIterable, string_types, range, builtins, integer_types, PY3)
from sympy.utilities.decorator import doctest_depends_on
__doctest_requires__ = {('lambdify',): ['numpy', 'tensorflow']}
# Default namespaces, letting us define translations that can't be defined
# by simple variable maps, like I => 1j
MATH_DEFAULT = {}
MPMATH_DEFAULT = {}
NUMPY_DEFAULT = {"I": 1j}
SCIPY_DEFAULT = {"I": 1j}
TENSORFLOW_DEFAULT = {}
SYMPY_DEFAULT = {}
NUMEXPR_DEFAULT = {}
# These are the namespaces the lambda functions will use.
# These are separate from the names above because they are modified
# throughout this file, whereas the defaults should remain unmodified.
MATH = MATH_DEFAULT.copy()
MPMATH = MPMATH_DEFAULT.copy()
NUMPY = NUMPY_DEFAULT.copy()
SCIPY = SCIPY_DEFAULT.copy()
TENSORFLOW = TENSORFLOW_DEFAULT.copy()
SYMPY = SYMPY_DEFAULT.copy()
NUMEXPR = NUMEXPR_DEFAULT.copy()
# Mappings between sympy and other modules function names.
MATH_TRANSLATIONS = {
"ceiling": "ceil",
"E": "e",
"ln": "log",
}
MPMATH_TRANSLATIONS = {
"Abs": "fabs",
"elliptic_k": "ellipk",
"elliptic_f": "ellipf",
"elliptic_e": "ellipe",
"elliptic_pi": "ellippi",
"ceiling": "ceil",
"chebyshevt": "chebyt",
"chebyshevu": "chebyu",
"E": "e",
"I": "j",
"ln": "log",
#"lowergamma":"lower_gamma",
"oo": "inf",
#"uppergamma":"upper_gamma",
"LambertW": "lambertw",
"MutableDenseMatrix": "matrix",
"ImmutableDenseMatrix": "matrix",
"conjugate": "conj",
"dirichlet_eta": "altzeta",
"Ei": "ei",
"Shi": "shi",
"Chi": "chi",
"Si": "si",
"Ci": "ci",
"RisingFactorial": "rf",
"FallingFactorial": "ff",
}
NUMPY_TRANSLATIONS = {}
SCIPY_TRANSLATIONS = {}
TENSORFLOW_TRANSLATIONS = {
"Abs": "abs",
"ceiling": "ceil",
"im": "imag",
"ln": "log",
"Mod": "mod",
"conjugate": "conj",
"re": "real",
}
NUMEXPR_TRANSLATIONS = {}
# Available modules:
MODULES = {
"math": (MATH, MATH_DEFAULT, MATH_TRANSLATIONS, ("from math import *",)),
"mpmath": (MPMATH, MPMATH_DEFAULT, MPMATH_TRANSLATIONS, ("from mpmath import *",)),
"numpy": (NUMPY, NUMPY_DEFAULT, NUMPY_TRANSLATIONS, ("import numpy; from numpy import *; from numpy.linalg import *",)),
"scipy": (SCIPY, SCIPY_DEFAULT, SCIPY_TRANSLATIONS, ("import numpy; import scipy; from scipy import *; from scipy.special import *",)),
"tensorflow": (TENSORFLOW, TENSORFLOW_DEFAULT, TENSORFLOW_TRANSLATIONS, ("import_module('tensorflow')",)),
"sympy": (SYMPY, SYMPY_DEFAULT, {}, (
"from sympy.functions import *",
"from sympy.matrices import *",
"from sympy import Integral, pi, oo, nan, zoo, E, I",)),
"numexpr" : (NUMEXPR, NUMEXPR_DEFAULT, NUMEXPR_TRANSLATIONS,
("import_module('numexpr')", )),
}
def _import(module, reload=False):
"""
Creates a global translation dictionary for module.
The argument module has to be one of the following strings: "math",
"mpmath", "numpy", "sympy", "tensorflow".
These dictionaries map names of python functions to their equivalent in
other modules.
"""
from sympy.external import import_module
try:
namespace, namespace_default, translations, import_commands = MODULES[
module]
except KeyError:
raise NameError(
"'%s' module can't be used for lambdification" % module)
# Clear namespace or exit
if namespace != namespace_default:
# The namespace was already generated, don't do it again if not forced.
if reload:
namespace.clear()
namespace.update(namespace_default)
else:
return
for import_command in import_commands:
if import_command.startswith('import_module'):
module = eval(import_command)
if module is not None:
namespace.update(module.__dict__)
continue
else:
try:
exec_(import_command, {}, namespace)
continue
except ImportError:
pass
raise ImportError(
"can't import '%s' with '%s' command" % (module, import_command))
# Add translated names to namespace
for sympyname, translation in translations.items():
namespace[sympyname] = namespace[translation]
# For computing the modulus of a sympy expression we use the builtin abs
# function, instead of the previously used fabs function for all
# translation modules. This is because the fabs function in the math
# module does not accept complex valued arguments. (see issue 9474). The
# only exception, where we don't use the builtin abs function is the
# mpmath translation module, because mpmath.fabs returns mpf objects in
# contrast to abs().
if 'Abs' not in namespace:
namespace['Abs'] = abs
# Used for dynamically generated filenames that are inserted into the
# linecache.
_lambdify_generated_counter = 1
@doctest_depends_on(modules=('numpy'))
def lambdify(args, expr, modules=None, printer=None, use_imps=True,
dummify=False):
"""
Returns an anonymous function for fast calculation of numerical values.
If not specified differently by the user, ``modules`` defaults to
``["scipy", "numpy"]`` if SciPy is installed, ``["numpy"]`` if only
NumPy is installed, and ``["math", "mpmath", "sympy"]`` if neither is
installed. That is, SymPy functions are replaced as far as possible by
either ``scipy`` or ``numpy`` functions if available, and Python's
standard library ``math``, or ``mpmath`` functions otherwise. To change
this behavior, the "modules" argument can be used. It accepts:
- the strings "math", "mpmath", "numpy", "numexpr", "scipy", "sympy",
"tensorflow"
- any modules (e.g. math)
- dictionaries that map names of sympy functions to arbitrary functions
- lists that contain a mix of the arguments above, with higher priority
given to entries appearing first.
.. warning::
Note that this function uses ``eval``, and thus shouldn't be used on
unsanitized input.
Arguments in the provided expression that are not valid Python identifiers
are substitued with dummy symbols. This allows for applied functions
(e.g. f(t)) to be supplied as arguments. Call the function with
dummify=True to replace all arguments with dummy symbols (if `args` is
not a string) - for example, to ensure that the arguments do not
redefine any built-in names.
For functions involving large array calculations, numexpr can provide a
significant speedup over numpy. Please note that the available functions
for numexpr are more limited than numpy but can be expanded with
implemented_function and user defined subclasses of Function. If specified,
numexpr may be the only option in modules. The official list of numexpr
functions can be found at:
https://github.com/pydata/numexpr#supported-functions
In previous releases ``lambdify`` replaced ``Matrix`` with ``numpy.matrix``
by default. As of release 1.0 ``numpy.array`` is the default.
To get the old default behavior you must pass in ``[{'ImmutableDenseMatrix':
numpy.matrix}, 'numpy']`` to the ``modules`` kwarg.
>>> from sympy import lambdify, Matrix
>>> from sympy.abc import x, y
>>> import numpy
>>> array2mat = [{'ImmutableDenseMatrix': numpy.matrix}, 'numpy']
>>> f = lambdify((x, y), Matrix([x, y]), modules=array2mat)
>>> f(1, 2)
[[1]
[2]]
Usage
=====
(1) Use one of the provided modules:
>>> from sympy import sin, tan, gamma
>>> from sympy.abc import x, y
>>> f = lambdify(x, sin(x), "math")
Attention: Functions that are not in the math module will throw a name
error when the function definition is evaluated! So this
would be better:
>>> f = lambdify(x, sin(x)*gamma(x), ("math", "mpmath", "sympy"))
(2) Use some other module:
>>> import numpy
>>> f = lambdify((x,y), tan(x*y), numpy)
Attention: There are naming differences between numpy and sympy. So if
you simply take the numpy module, e.g. sympy.atan will not be
translated to numpy.arctan. Use the modified module instead
by passing the string "numpy":
>>> f = lambdify((x,y), tan(x*y), "numpy")
>>> f(1, 2)
-2.18503986326
>>> from numpy import array
>>> f(array([1, 2, 3]), array([2, 3, 5]))
[-2.18503986 -0.29100619 -0.8559934 ]
In the above examples, the generated functions can accept scalar
values or numpy arrays as arguments. However, in some cases
the generated function relies on the input being a numpy array:
>>> from sympy import Piecewise
>>> from sympy.utilities.pytest import ignore_warnings
>>> f = lambdify(x, Piecewise((x, x <= 1), (1/x, x > 1)), "numpy")
>>> with ignore_warnings(RuntimeWarning):
... f(array([-1, 0, 1, 2]))
[-1. 0. 1. 0.5]
>>> f(0)
Traceback (most recent call last):
...
ZeroDivisionError: division by zero
In such cases, the input should be wrapped in a numpy array:
>>> with ignore_warnings(RuntimeWarning):
... float(f(array([0])))
0.0
Or if numpy functionality is not required another module can be used:
>>> f = lambdify(x, Piecewise((x, x <= 1), (1/x, x > 1)), "math")
>>> f(0)
0
(3) Use a dictionary defining custom functions:
>>> def my_cool_function(x): return 'sin(%s) is cool' % x
>>> myfuncs = {"sin" : my_cool_function}
>>> f = lambdify(x, sin(x), myfuncs); f(1)
'sin(1) is cool'
Examples
========
>>> from sympy.utilities.lambdify import implemented_function
>>> from sympy import sqrt, sin, Matrix
>>> from sympy import Function
>>> from sympy.abc import w, x, y, z
>>> f = lambdify(x, x**2)
>>> f(2)
4
>>> f = lambdify((x, y, z), [z, y, x])
>>> f(1,2,3)
[3, 2, 1]
>>> f = lambdify(x, sqrt(x))
>>> f(4)
2.0
>>> f = lambdify((x, y), sin(x*y)**2)
>>> f(0, 5)
0.0
>>> row = lambdify((x, y), Matrix((x, x + y)).T, modules='sympy')
>>> row(1, 2)
Matrix([[1, 3]])
Tuple arguments are handled and the lambdified function should
be called with the same type of arguments as were used to create
the function.:
>>> f = lambdify((x, (y, z)), x + y)
>>> f(1, (2, 4))
3
A more robust way of handling this is to always work with flattened
arguments:
>>> from sympy.utilities.iterables import flatten
>>> args = w, (x, (y, z))
>>> vals = 1, (2, (3, 4))
>>> f = lambdify(flatten(args), w + x + y + z)
>>> f(*flatten(vals))
10
Functions present in `expr` can also carry their own numerical
implementations, in a callable attached to the ``_imp_``
attribute. Usually you attach this using the
``implemented_function`` factory:
>>> f = implemented_function(Function('f'), lambda x: x+1)
>>> func = lambdify(x, f(x))
>>> func(4)
5
``lambdify`` always prefers ``_imp_`` implementations to implementations
in other namespaces, unless the ``use_imps`` input parameter is False.
Usage with Tensorflow module:
>>> import tensorflow as tf
>>> f = Max(x, sin(x))
>>> func = lambdify(x, f, 'tensorflow')
>>> result = func(tf.constant(1.0))
>>> result # a tf.Tensor representing the result of the calculation
<tf.Tensor 'Maximum:0' shape=() dtype=float32>
>>> sess = tf.Session()
>>> sess.run(result) # compute result
1.0
>>> var = tf.Variable(1.0)
>>> sess.run(tf.global_variables_initializer())
>>> sess.run(func(var)) # also works for tf.Variable and tf.Placeholder
1.0
>>> tensor = tf.constant([[1.0, 2.0], [3.0, 4.0]]) # works with any shape tensor
>>> sess.run(func(tensor))
array([[ 1., 2.],
[ 3., 4.]], dtype=float32)
"""
from sympy.core.symbol import Symbol
from sympy.utilities.iterables import flatten
# If the user hasn't specified any modules, use what is available.
module_provided = True
if modules is None:
module_provided = False
try:
_import("scipy")
except ImportError:
try:
_import("numpy")
except ImportError:
# Use either numpy (if available) or python.math where possible.
# XXX: This leads to different behaviour on different systems and
# might be the reason for irreproducible errors.
modules = ["math", "mpmath", "sympy"]
else:
modules = ["numpy"]
else:
modules = ["scipy", "numpy"]
# Get the needed namespaces.
namespaces = []
# First find any function implementations
if use_imps:
namespaces.append(_imp_namespace(expr))
# Check for dict before iterating
if isinstance(modules, (dict, str)) or not hasattr(modules, '__iter__'):
namespaces.append(modules)
else:
# consistency check
if _module_present('numexpr', modules) and len(modules) > 1:
raise TypeError("numexpr must be the only item in 'modules'")
namespaces += list(modules)
# fill namespace with first having highest priority
namespace = {}
for m in namespaces[::-1]:
buf = _get_namespace(m)
namespace.update(buf)
if hasattr(expr, "atoms"):
#Try if you can extract symbols from the expression.
#Move on if expr.atoms in not implemented.
syms = expr.atoms(Symbol)
for term in syms:
namespace.update({str(term): term})
if printer is None:
if _module_present('mpmath', namespaces):
from sympy.printing.pycode import MpmathPrinter as Printer
elif _module_present('scipy', namespaces):
from sympy.printing.pycode import SciPyPrinter as Printer
elif _module_present('numpy', namespaces):
from sympy.printing.pycode import NumPyPrinter as Printer
elif _module_present('numexpr', namespaces):
from sympy.printing.lambdarepr import NumExprPrinter as Printer
elif _module_present('tensorflow', namespaces):
from sympy.printing.tensorflow import TensorflowPrinter as Printer
elif _module_present('sympy', namespaces):
from sympy.printing.pycode import SymPyPrinter as Printer
else:
from sympy.printing.pycode import PythonCodePrinter as Printer
user_functions = {}
for m in namespaces[::-1]:
if isinstance(m, dict):
for k in m:
user_functions[k] = k
printer = Printer({'fully_qualified_modules': False, 'inline': True,
'allow_unknown_functions': True,
'user_functions': user_functions})
# Get the names of the args, for creating a docstring
if not iterable(args):
args = (args,)
names = []
# Grab the callers frame, for getting the names by inspection (if needed)
callers_local_vars = inspect.currentframe().f_back.f_locals.items()
for n, var in enumerate(args):
if hasattr(var, 'name'):
names.append(var.name)
else:
# It's an iterable. Try to get name by inspection of calling frame.
name_list = [var_name for var_name, var_val in callers_local_vars
if var_val is var]
if len(name_list) == 1:
names.append(name_list[0])
else:
# Cannot infer name with certainty. arg_# will have to do.
names.append('arg_' + str(n))
imp_mod_lines = []
for mod, keys in (getattr(printer, 'module_imports', None) or {}).items():
for k in keys:
if k not in namespace:
imp_mod_lines.append("from %s import %s" % (mod, k))
for ln in imp_mod_lines:
exec_(ln, {}, namespace)
# Provide lambda expression with builtins, and compatible implementation of range
namespace.update({'builtins':builtins, 'range':range})
# Create the function definition code and execute it
funcname = '_lambdifygenerated'
if _module_present('tensorflow', namespaces):
funcprinter = _TensorflowEvaluatorPrinter(printer, dummify)
else:
funcprinter = _EvaluatorPrinter(printer, dummify)
funcstr = funcprinter.doprint(funcname, args, expr)
funclocals = {}
global _lambdify_generated_counter
filename = '<lambdifygenerated-%s>' % _lambdify_generated_counter
_lambdify_generated_counter += 1
c = compile(funcstr, filename, 'exec')
exec_(c, namespace, funclocals)
# mtime has to be None or else linecache.checkcache will remove it
linecache.cache[filename] = (len(funcstr), None, funcstr.splitlines(True), filename)
func = funclocals[funcname]
# Apply the docstring
sig = "func({0})".format(", ".join(str(i) for i in names))
sig = textwrap.fill(sig, subsequent_indent=' '*8)
expr_str = str(expr)
if len(expr_str) > 78:
expr_str = textwrap.wrap(expr_str, 75)[0] + '...'
func.__doc__ = (
"Created with lambdify. Signature:\n\n"
"{sig}\n\n"
"Expression:\n\n"
"{expr}\n\n"
"Source code:\n\n"
"{src}\n\n"
"Imported modules:\n\n"
"{imp_mods}"
).format(sig=sig, expr=expr_str, src=funcstr, imp_mods='\n'.join(imp_mod_lines))
return func
def _module_present(modname, modlist):
if modname in modlist:
return True
for m in modlist:
if hasattr(m, '__name__') and m.__name__ == modname:
return True
return False
def _get_namespace(m):
"""
This is used by _lambdify to parse its arguments.
"""
if isinstance(m, string_types):
_import(m)
return MODULES[m][0]
elif isinstance(m, dict):
return m
elif hasattr(m, "__dict__"):
return m.__dict__
else:
raise TypeError("Argument must be either a string, dict or module but it is: %s" % m)
def lambdastr(args, expr, printer=None, dummify=None):
"""
Returns a string that can be evaluated to a lambda function.
Examples
========
>>> from sympy.abc import x, y, z
>>> from sympy.utilities.lambdify import lambdastr
>>> lambdastr(x, x**2)
'lambda x: (x**2)'
>>> lambdastr((x,y,z), [z,y,x])
'lambda x,y,z: ([z, y, x])'
Although tuples may not appear as arguments to lambda in Python 3,
lambdastr will create a lambda function that will unpack the original
arguments so that nested arguments can be handled:
>>> lambdastr((x, (y, z)), x + y)
'lambda _0,_1: (lambda x,y,z: (x + y))(_0,_1[0],_1[1])'
"""
# Transforming everything to strings.
from sympy.matrices import DeferredVector
from sympy import Dummy, sympify, Symbol, Function, flatten, Derivative, Basic
if printer is not None:
if inspect.isfunction(printer):
lambdarepr = printer
else:
if inspect.isclass(printer):
lambdarepr = lambda expr: printer().doprint(expr)
else:
lambdarepr = lambda expr: printer.doprint(expr)
else:
#XXX: This has to be done here because of circular imports
from sympy.printing.lambdarepr import lambdarepr
def sub_args(args, dummies_dict):
if isinstance(args, str):
return args
elif isinstance(args, DeferredVector):
return str(args)
elif iterable(args):
dummies = flatten([sub_args(a, dummies_dict) for a in args])
return ",".join(str(a) for a in dummies)
else:
# replace these with Dummy symbols
if isinstance(args, (Function, Symbol, Derivative)):
dummies = Dummy()
dummies_dict.update({args : dummies})
return str(dummies)
else:
return str(args)
def sub_expr(expr, dummies_dict):
try:
expr = sympify(expr).xreplace(dummies_dict)
except Exception:
if isinstance(expr, DeferredVector):
pass
elif isinstance(expr, dict):
k = [sub_expr(sympify(a), dummies_dict) for a in expr.keys()]
v = [sub_expr(sympify(a), dummies_dict) for a in expr.values()]
expr = dict(zip(k, v))
elif isinstance(expr, tuple):
expr = tuple(sub_expr(sympify(a), dummies_dict) for a in expr)
elif isinstance(expr, list):
expr = [sub_expr(sympify(a), dummies_dict) for a in expr]
return expr
# Transform args
def isiter(l):
return iterable(l, exclude=(str, DeferredVector, NotIterable))
def flat_indexes(iterable):
n = 0
for el in iterable:
if isiter(el):
for ndeep in flat_indexes(el):
yield (n,) + ndeep
else:
yield (n,)
n += 1
if dummify is None:
dummify = any(isinstance(a, Basic) and
a.atoms(Function, Derivative) for a in (
args if isiter(args) else [args]))
if isiter(args) and any(isiter(i) for i in args):
dum_args = [str(Dummy(str(i))) for i in range(len(args))]
indexed_args = ','.join([
dum_args[ind[0]] + ''.join(["[%s]" % k for k in ind[1:]])
for ind in flat_indexes(args)])
lstr = lambdastr(flatten(args), expr, printer=printer, dummify=dummify)
return 'lambda %s: (%s)(%s)' % (','.join(dum_args), lstr, indexed_args)
dummies_dict = {}
if dummify:
args = sub_args(args, dummies_dict)
else:
if isinstance(args, str):
pass
elif iterable(args, exclude=DeferredVector):
args = ",".join(str(a) for a in args)
# Transform expr
if dummify:
if isinstance(expr, str):
pass
else:
expr = sub_expr(expr, dummies_dict)
expr = lambdarepr(expr)
return "lambda %s: (%s)" % (args, expr)
class _EvaluatorPrinter(object):
def __init__(self, printer=None, dummify=False):
self._dummify = dummify
#XXX: This has to be done here because of circular imports
from sympy.printing.lambdarepr import LambdaPrinter
if printer is None:
printer = LambdaPrinter()
if inspect.isfunction(printer):
self._exprrepr = printer
else:
if inspect.isclass(printer):
printer = printer()
self._exprrepr = printer.doprint
if hasattr(printer, '_print_Symbol'):
symbolrepr = printer._print_Symbol
if hasattr(printer, '_print_Dummy'):
dummyrepr = printer._print_Dummy
# Used to print the generated function arguments in a standard way
self._argrepr = LambdaPrinter().doprint
def doprint(self, funcname, args, expr):
"""Returns the function definition code as a string."""
from sympy import Dummy
funcbody = []
if not iterable(args):
args = [args]
argstrs, expr = self._preprocess(args, expr)
# Generate argument unpacking and final argument list
funcargs = []
unpackings = []
for argstr in argstrs:
if iterable(argstr):
funcargs.append(self._argrepr(Dummy()))
unpackings.extend(self._print_unpacking(argstr, funcargs[-1]))
else:
funcargs.append(argstr)
funcsig = 'def {}({}):'.format(funcname, ', '.join(funcargs))
# Wrap input arguments before unpacking
funcbody.extend(self._print_funcargwrapping(funcargs))
funcbody.extend(unpackings)
funcbody.append('return ({})'.format(self._exprrepr(expr)))
funclines = [funcsig]
funclines.extend(' ' + line for line in funcbody)
return '\n'.join(funclines) + '\n'
if PY3:
@classmethod
def _is_safe_ident(cls, ident):
return isinstance(ident, str) and ident.isidentifier() \
and not keyword.iskeyword(ident)
else:
_safe_ident_re = re.compile('^[a-zA-Z_][a-zA-Z0-9_]*$')
@classmethod
def _is_safe_ident(cls, ident):
return isinstance(ident, str) and cls._safe_ident_re.match(ident) \
and not (keyword.iskeyword(ident) or ident == 'None')
def _preprocess(self, args, expr):
"""Preprocess args, expr to replace arguments that do not map
to valid Python identifiers.
Returns string form of args, and updated expr.
"""
from sympy import Dummy, Function, flatten, Derivative, ordered, Basic
from sympy.matrices import DeferredVector
# Args of type Dummy can cause name collisions with args
# of type Symbol. Force dummify of everything in this
# situation.
dummify = self._dummify or any(
isinstance(arg, Dummy) for arg in flatten(args))
argstrs = [None]*len(args)
for arg, i in reversed(list(ordered(zip(args, range(len(args)))))):
if iterable(arg):
s, expr = self._preprocess(arg, expr)
elif isinstance(arg, DeferredVector):
s = str(arg)
elif isinstance(arg, Basic) and arg.is_symbol:
s = self._argrepr(arg)
if dummify or not self._is_safe_ident(s):
dummy = Dummy()
s = self._argrepr(dummy)
expr = self._subexpr(expr, {arg: dummy})
elif dummify or isinstance(arg, (Function, Derivative)):
dummy = Dummy()
s = self._argrepr(dummy)
expr = self._subexpr(expr, {arg: dummy})
else:
s = str(arg)
argstrs[i] = s
return argstrs, expr
def _subexpr(self, expr, dummies_dict):
from sympy.matrices import DeferredVector
from sympy import sympify
try:
expr = sympify(expr).xreplace(dummies_dict)
except AttributeError:
if isinstance(expr, DeferredVector):
pass
elif isinstance(expr, dict):
k = [self._subexpr(sympify(a), dummies_dict) for a in expr.keys()]
v = [self._subexpr(sympify(a), dummies_dict) for a in expr.values()]
expr = dict(zip(k, v))
elif isinstance(expr, tuple):
expr = tuple(self._subexpr(sympify(a), dummies_dict) for a in expr)
elif isinstance(expr, list):
expr = [self._subexpr(sympify(a), dummies_dict) for a in expr]
return expr
def _print_funcargwrapping(self, args):
"""Generate argument wrapping code.
args is the argument list of the generated function (strings).
Return value is a list of lines of code that will be inserted at
the beginning of the function definition.
"""
return []
def _print_unpacking(self, unpackto, arg):
"""Generate argument unpacking code.
arg is the function argument to be unpacked (a string), and
unpackto is a list or nested lists of the variable names (strings) to
unpack to.
"""
def unpack_lhs(lvalues):
return '[{}]'.format(', '.join(
unpack_lhs(val) if iterable(val) else val for val in lvalues))
return ['{} = {}'.format(unpack_lhs(unpackto), arg)]
class _TensorflowEvaluatorPrinter(_EvaluatorPrinter):
def _print_unpacking(self, lvalues, rvalue):
"""Generate argument unpacking code.
This method is used when the input value is not interable,
but can be indexed (see issue #14655).
"""
from sympy import flatten
def flat_indexes(elems):
n = 0
for el in elems:
if iterable(el):
for ndeep in flat_indexes(el):
yield (n,) + ndeep
else:
yield (n,)
n += 1
indexed = ', '.join('{}[{}]'.format(rvalue, ']['.join(map(str, ind)))
for ind in flat_indexes(lvalues))
return ['[{}] = [{}]'.format(', '.join(flatten(lvalues)), indexed)]
def _imp_namespace(expr, namespace=None):
""" Return namespace dict with function implementations
We need to search for functions in anything that can be thrown at
us - that is - anything that could be passed as `expr`. Examples
include sympy expressions, as well as tuples, lists and dicts that may
contain sympy expressions.
Parameters
----------
expr : object
Something passed to lambdify, that will generate valid code from
``str(expr)``.
namespace : None or mapping
Namespace to fill. None results in new empty dict
Returns
-------
namespace : dict
dict with keys of implemented function names within `expr` and
corresponding values being the numerical implementation of
function
Examples
========
>>> from sympy.abc import x
>>> from sympy.utilities.lambdify import implemented_function, _imp_namespace
>>> from sympy import Function
>>> f = implemented_function(Function('f'), lambda x: x+1)
>>> g = implemented_function(Function('g'), lambda x: x*10)
>>> namespace = _imp_namespace(f(g(x)))
>>> sorted(namespace.keys())
['f', 'g']
"""
# Delayed import to avoid circular imports
from sympy.core.function import FunctionClass
if namespace is None:
namespace = {}
# tuples, lists, dicts are valid expressions
if is_sequence(expr):
for arg in expr:
_imp_namespace(arg, namespace)
return namespace
elif isinstance(expr, dict):
for key, val in expr.items():
# functions can be in dictionary keys
_imp_namespace(key, namespace)
_imp_namespace(val, namespace)
return namespace
# sympy expressions may be Functions themselves
func = getattr(expr, 'func', None)
if isinstance(func, FunctionClass):
imp = getattr(func, '_imp_', None)
if imp is not None:
name = expr.func.__name__
if name in namespace and namespace[name] != imp:
raise ValueError('We found more than one '
'implementation with name '
'"%s"' % name)
namespace[name] = imp
# and / or they may take Functions as arguments
if hasattr(expr, 'args'):
for arg in expr.args:
_imp_namespace(arg, namespace)
return namespace
def implemented_function(symfunc, implementation):
""" Add numerical ``implementation`` to function ``symfunc``.
``symfunc`` can be an ``UndefinedFunction`` instance, or a name string.
In the latter case we create an ``UndefinedFunction`` instance with that
name.
Be aware that this is a quick workaround, not a general method to create
special symbolic functions. If you want to create a symbolic function to be
used by all the machinery of SymPy you should subclass the ``Function``
class.
Parameters
----------
symfunc : ``str`` or ``UndefinedFunction`` instance
If ``str``, then create new ``UndefinedFunction`` with this as
name. If `symfunc` is an Undefined function, create a new function
with the same name and the implemented function attached.
implementation : callable
numerical implementation to be called by ``evalf()`` or ``lambdify``
Returns
-------
afunc : sympy.FunctionClass instance
function with attached implementation
Examples
========
>>> from sympy.abc import x
>>> from sympy.utilities.lambdify import lambdify, implemented_function
>>> from sympy import Function
>>> f = implemented_function('f', lambda x: x+1)
>>> lam_f = lambdify(x, f(x))
>>> lam_f(4)
5
"""
# Delayed import to avoid circular imports
from sympy.core.function import UndefinedFunction
# if name, create function to hold implementation
_extra_kwargs = {}
if isinstance(symfunc, UndefinedFunction):
_extra_kwargs = symfunc._extra_kwargs
symfunc = symfunc.__name__
if isinstance(symfunc, string_types):
# Keyword arguments to UndefinedFunction are added as attributes to
# the created class.
symfunc = UndefinedFunction(symfunc, _imp_=staticmethod(implementation), **_extra_kwargs)
elif not isinstance(symfunc, UndefinedFunction):
raise ValueError('symfunc should be either a string or'
' an UndefinedFunction instance.')
return symfunc
|
dd5c44ec5077817f76fa6c3bc519a1deb1a47df46f22f48e815abf3459019212
|
"""Useful utility decorators. """
from __future__ import print_function, division
import sys
import types
import inspect
from functools import update_wrapper
from sympy.core.decorators import wraps
from sympy.core.compatibility import class_types, get_function_globals, get_function_name, iterable
from sympy.utilities.runtests import DependencyError, SymPyDocTests, PyTestReporter
def threaded_factory(func, use_add):
"""A factory for ``threaded`` decorators. """
from sympy.core import sympify
from sympy.matrices import MatrixBase
@wraps(func)
def threaded_func(expr, *args, **kwargs):
if isinstance(expr, MatrixBase):
return expr.applyfunc(lambda f: func(f, *args, **kwargs))
elif iterable(expr):
try:
return expr.__class__([func(f, *args, **kwargs) for f in expr])
except TypeError:
return expr
else:
expr = sympify(expr)
if use_add and expr.is_Add:
return expr.__class__(*[ func(f, *args, **kwargs) for f in expr.args ])
elif expr.is_Relational:
return expr.__class__(func(expr.lhs, *args, **kwargs),
func(expr.rhs, *args, **kwargs))
else:
return func(expr, *args, **kwargs)
return threaded_func
def threaded(func):
"""Apply ``func`` to sub--elements of an object, including :class:`Add`.
This decorator is intended to make it uniformly possible to apply a
function to all elements of composite objects, e.g. matrices, lists, tuples
and other iterable containers, or just expressions.
This version of :func:`threaded` decorator allows threading over
elements of :class:`Add` class. If this behavior is not desirable
use :func:`xthreaded` decorator.
Functions using this decorator must have the following signature::
@threaded
def function(expr, *args, **kwargs):
"""
return threaded_factory(func, True)
def xthreaded(func):
"""Apply ``func`` to sub--elements of an object, excluding :class:`Add`.
This decorator is intended to make it uniformly possible to apply a
function to all elements of composite objects, e.g. matrices, lists, tuples
and other iterable containers, or just expressions.
This version of :func:`threaded` decorator disallows threading over
elements of :class:`Add` class. If this behavior is not desirable
use :func:`threaded` decorator.
Functions using this decorator must have the following signature::
@xthreaded
def function(expr, *args, **kwargs):
"""
return threaded_factory(func, False)
def conserve_mpmath_dps(func):
"""After the function finishes, resets the value of mpmath.mp.dps to
the value it had before the function was run."""
import functools
import mpmath
def func_wrapper(*args, **kwargs):
dps = mpmath.mp.dps
try:
return func(*args, **kwargs)
finally:
mpmath.mp.dps = dps
func_wrapper = functools.update_wrapper(func_wrapper, func)
return func_wrapper
class no_attrs_in_subclass(object):
"""Don't 'inherit' certain attributes from a base class
>>> from sympy.utilities.decorator import no_attrs_in_subclass
>>> class A(object):
... x = 'test'
>>> A.x = no_attrs_in_subclass(A, A.x)
>>> class B(A):
... pass
>>> hasattr(A, 'x')
True
>>> hasattr(B, 'x')
False
"""
def __init__(self, cls, f):
self.cls = cls
self.f = f
def __get__(self, instance, owner=None):
if owner == self.cls:
if hasattr(self.f, '__get__'):
return self.f.__get__(instance, owner)
return self.f
raise AttributeError
def doctest_depends_on(exe=None, modules=None, disable_viewers=None):
"""Adds metadata about the dependencies which need to be met for doctesting
the docstrings of the decorated objects."""
dependencies = {}
if exe is not None:
dependencies['executables'] = exe
if modules is not None:
dependencies['modules'] = modules
if disable_viewers is not None:
dependencies['disable_viewers'] = disable_viewers
def skiptests():
r = PyTestReporter()
t = SymPyDocTests(r, None)
try:
t._check_dependencies(**dependencies)
except DependencyError:
return True # Skip doctests
else:
return False # Run doctests
def depends_on_deco(fn):
fn._doctest_depends_on = dependencies
fn.__doctest_skip__ = skiptests
if inspect.isclass(fn):
fn._doctest_depdends_on = no_attrs_in_subclass(
fn, fn._doctest_depends_on)
fn.__doctest_skip__ = no_attrs_in_subclass(
fn, fn.__doctest_skip__)
return fn
return depends_on_deco
def public(obj):
"""
Append ``obj``'s name to global ``__all__`` variable (call site).
By using this decorator on functions or classes you achieve the same goal
as by filling ``__all__`` variables manually, you just don't have to repeat
yourself (object's name). You also know if object is public at definition
site, not at some random location (where ``__all__`` was set).
Note that in multiple decorator setup (in almost all cases) ``@public``
decorator must be applied before any other decorators, because it relies
on the pointer to object's global namespace. If you apply other decorators
first, ``@public`` may end up modifying the wrong namespace.
Examples
========
>>> from sympy.utilities.decorator import public
>>> __all__
Traceback (most recent call last):
...
NameError: name '__all__' is not defined
>>> @public
... def some_function():
... pass
>>> __all__
['some_function']
"""
if isinstance(obj, types.FunctionType):
ns = get_function_globals(obj)
name = get_function_name(obj)
elif isinstance(obj, (type(type), class_types)):
ns = sys.modules[obj.__module__].__dict__
name = obj.__name__
else:
raise TypeError("expected a function or a class, got %s" % obj)
if "__all__" not in ns:
ns["__all__"] = [name]
else:
ns["__all__"].append(name)
return obj
def memoize_property(storage):
"""Create a property, where the lookup is stored in ``storage``"""
def decorator(method):
name = method.__name__
def wrapper(self):
if name not in storage:
storage[name] = method(self)
return storage[name]
return property(update_wrapper(wrapper, method))
return decorator
|
95b4da5ea3ef2158d02b6e4472e29b0f7755847c355091ca5e6214c92353980d
|
from __future__ import print_function, division
from collections import defaultdict
from itertools import (
combinations, combinations_with_replacement, permutations,
product, product as cartes
)
import random
from operator import gt
from sympy.core import Basic
# this is the logical location of these functions
from sympy.core.compatibility import (
as_int, default_sort_key, is_sequence, iterable, ordered, range
)
from sympy.utilities.enumerative import (
multiset_partitions_taocp, list_visitor, MultisetPartitionTraverser)
def flatten(iterable, levels=None, cls=None):
"""
Recursively denest iterable containers.
>>> from sympy.utilities.iterables import flatten
>>> flatten([1, 2, 3])
[1, 2, 3]
>>> flatten([1, 2, [3]])
[1, 2, 3]
>>> flatten([1, [2, 3], [4, 5]])
[1, 2, 3, 4, 5]
>>> flatten([1.0, 2, (1, None)])
[1.0, 2, 1, None]
If you want to denest only a specified number of levels of
nested containers, then set ``levels`` flag to the desired
number of levels::
>>> ls = [[(-2, -1), (1, 2)], [(0, 0)]]
>>> flatten(ls, levels=1)
[(-2, -1), (1, 2), (0, 0)]
If cls argument is specified, it will only flatten instances of that
class, for example:
>>> from sympy.core import Basic
>>> class MyOp(Basic):
... pass
...
>>> flatten([MyOp(1, MyOp(2, 3))], cls=MyOp)
[1, 2, 3]
adapted from https://kogs-www.informatik.uni-hamburg.de/~meine/python_tricks
"""
if levels is not None:
if not levels:
return iterable
elif levels > 0:
levels -= 1
else:
raise ValueError(
"expected non-negative number of levels, got %s" % levels)
if cls is None:
reducible = lambda x: is_sequence(x, set)
else:
reducible = lambda x: isinstance(x, cls)
result = []
for el in iterable:
if reducible(el):
if hasattr(el, 'args'):
el = el.args
result.extend(flatten(el, levels=levels, cls=cls))
else:
result.append(el)
return result
def unflatten(iter, n=2):
"""Group ``iter`` into tuples of length ``n``. Raise an error if
the length of ``iter`` is not a multiple of ``n``.
"""
if n < 1 or len(iter) % n:
raise ValueError('iter length is not a multiple of %i' % n)
return list(zip(*(iter[i::n] for i in range(n))))
def reshape(seq, how):
"""Reshape the sequence according to the template in ``how``.
Examples
========
>>> from sympy.utilities import reshape
>>> seq = list(range(1, 9))
>>> reshape(seq, [4]) # lists of 4
[[1, 2, 3, 4], [5, 6, 7, 8]]
>>> reshape(seq, (4,)) # tuples of 4
[(1, 2, 3, 4), (5, 6, 7, 8)]
>>> reshape(seq, (2, 2)) # tuples of 4
[(1, 2, 3, 4), (5, 6, 7, 8)]
>>> reshape(seq, (2, [2])) # (i, i, [i, i])
[(1, 2, [3, 4]), (5, 6, [7, 8])]
>>> reshape(seq, ((2,), [2])) # etc....
[((1, 2), [3, 4]), ((5, 6), [7, 8])]
>>> reshape(seq, (1, [2], 1))
[(1, [2, 3], 4), (5, [6, 7], 8)]
>>> reshape(tuple(seq), ([[1], 1, (2,)],))
(([[1], 2, (3, 4)],), ([[5], 6, (7, 8)],))
>>> reshape(tuple(seq), ([1], 1, (2,)))
(([1], 2, (3, 4)), ([5], 6, (7, 8)))
>>> reshape(list(range(12)), [2, [3], {2}, (1, (3,), 1)])
[[0, 1, [2, 3, 4], {5, 6}, (7, (8, 9, 10), 11)]]
"""
m = sum(flatten(how))
n, rem = divmod(len(seq), m)
if m < 0 or rem:
raise ValueError('template must sum to positive number '
'that divides the length of the sequence')
i = 0
container = type(how)
rv = [None]*n
for k in range(len(rv)):
rv[k] = []
for hi in how:
if type(hi) is int:
rv[k].extend(seq[i: i + hi])
i += hi
else:
n = sum(flatten(hi))
hi_type = type(hi)
rv[k].append(hi_type(reshape(seq[i: i + n], hi)[0]))
i += n
rv[k] = container(rv[k])
return type(seq)(rv)
def group(seq, multiple=True):
"""
Splits a sequence into a list of lists of equal, adjacent elements.
Examples
========
>>> from sympy.utilities.iterables import group
>>> group([1, 1, 1, 2, 2, 3])
[[1, 1, 1], [2, 2], [3]]
>>> group([1, 1, 1, 2, 2, 3], multiple=False)
[(1, 3), (2, 2), (3, 1)]
>>> group([1, 1, 3, 2, 2, 1], multiple=False)
[(1, 2), (3, 1), (2, 2), (1, 1)]
See Also
========
multiset
"""
if not seq:
return []
current, groups = [seq[0]], []
for elem in seq[1:]:
if elem == current[-1]:
current.append(elem)
else:
groups.append(current)
current = [elem]
groups.append(current)
if multiple:
return groups
for i, current in enumerate(groups):
groups[i] = (current[0], len(current))
return groups
def multiset(seq):
"""Return the hashable sequence in multiset form with values being the
multiplicity of the item in the sequence.
Examples
========
>>> from sympy.utilities.iterables import multiset
>>> multiset('mississippi')
{'i': 4, 'm': 1, 'p': 2, 's': 4}
See Also
========
group
"""
rv = defaultdict(int)
for s in seq:
rv[s] += 1
return dict(rv)
def postorder_traversal(node, keys=None):
"""
Do a postorder traversal of a tree.
This generator recursively yields nodes that it has visited in a postorder
fashion. That is, it descends through the tree depth-first to yield all of
a node's children's postorder traversal before yielding the node itself.
Parameters
==========
node : sympy expression
The expression to traverse.
keys : (default None) sort key(s)
The key(s) used to sort args of Basic objects. When None, args of Basic
objects are processed in arbitrary order. If key is defined, it will
be passed along to ordered() as the only key(s) to use to sort the
arguments; if ``key`` is simply True then the default keys of
``ordered`` will be used (node count and default_sort_key).
Yields
======
subtree : sympy expression
All of the subtrees in the tree.
Examples
========
>>> from sympy.utilities.iterables import postorder_traversal
>>> from sympy.abc import w, x, y, z
The nodes are returned in the order that they are encountered unless key
is given; simply passing key=True will guarantee that the traversal is
unique.
>>> list(postorder_traversal(w + (x + y)*z)) # doctest: +SKIP
[z, y, x, x + y, z*(x + y), w, w + z*(x + y)]
>>> list(postorder_traversal(w + (x + y)*z, keys=True))
[w, z, x, y, x + y, z*(x + y), w + z*(x + y)]
"""
if isinstance(node, Basic):
args = node.args
if keys:
if keys != True:
args = ordered(args, keys, default=False)
else:
args = ordered(args)
for arg in args:
for subtree in postorder_traversal(arg, keys):
yield subtree
elif iterable(node):
for item in node:
for subtree in postorder_traversal(item, keys):
yield subtree
yield node
def interactive_traversal(expr):
"""Traverse a tree asking a user which branch to choose. """
from sympy.printing import pprint
RED, BRED = '\033[0;31m', '\033[1;31m'
GREEN, BGREEN = '\033[0;32m', '\033[1;32m'
YELLOW, BYELLOW = '\033[0;33m', '\033[1;33m'
BLUE, BBLUE = '\033[0;34m', '\033[1;34m'
MAGENTA, BMAGENTA = '\033[0;35m', '\033[1;35m'
CYAN, BCYAN = '\033[0;36m', '\033[1;36m'
END = '\033[0m'
def cprint(*args):
print("".join(map(str, args)) + END)
def _interactive_traversal(expr, stage):
if stage > 0:
print()
cprint("Current expression (stage ", BYELLOW, stage, END, "):")
print(BCYAN)
pprint(expr)
print(END)
if isinstance(expr, Basic):
if expr.is_Add:
args = expr.as_ordered_terms()
elif expr.is_Mul:
args = expr.as_ordered_factors()
else:
args = expr.args
elif hasattr(expr, "__iter__"):
args = list(expr)
else:
return expr
n_args = len(args)
if not n_args:
return expr
for i, arg in enumerate(args):
cprint(GREEN, "[", BGREEN, i, GREEN, "] ", BLUE, type(arg), END)
pprint(arg)
print
if n_args == 1:
choices = '0'
else:
choices = '0-%d' % (n_args - 1)
try:
choice = raw_input("Your choice [%s,f,l,r,d,?]: " % choices)
except EOFError:
result = expr
print()
else:
if choice == '?':
cprint(RED, "%s - select subexpression with the given index" %
choices)
cprint(RED, "f - select the first subexpression")
cprint(RED, "l - select the last subexpression")
cprint(RED, "r - select a random subexpression")
cprint(RED, "d - done\n")
result = _interactive_traversal(expr, stage)
elif choice in ['d', '']:
result = expr
elif choice == 'f':
result = _interactive_traversal(args[0], stage + 1)
elif choice == 'l':
result = _interactive_traversal(args[-1], stage + 1)
elif choice == 'r':
result = _interactive_traversal(random.choice(args), stage + 1)
else:
try:
choice = int(choice)
except ValueError:
cprint(BRED,
"Choice must be a number in %s range\n" % choices)
result = _interactive_traversal(expr, stage)
else:
if choice < 0 or choice >= n_args:
cprint(BRED, "Choice must be in %s range\n" % choices)
result = _interactive_traversal(expr, stage)
else:
result = _interactive_traversal(args[choice], stage + 1)
return result
return _interactive_traversal(expr, 0)
def ibin(n, bits=0, str=False):
"""Return a list of length ``bits`` corresponding to the binary value
of ``n`` with small bits to the right (last). If bits is omitted, the
length will be the number required to represent ``n``. If the bits are
desired in reversed order, use the [::-1] slice of the returned list.
If a sequence of all bits-length lists starting from [0, 0,..., 0]
through [1, 1, ..., 1] are desired, pass a non-integer for bits, e.g.
'all'.
If the bit *string* is desired pass ``str=True``.
Examples
========
>>> from sympy.utilities.iterables import ibin
>>> ibin(2)
[1, 0]
>>> ibin(2, 4)
[0, 0, 1, 0]
>>> ibin(2, 4)[::-1]
[0, 1, 0, 0]
If all lists corresponding to 0 to 2**n - 1, pass a non-integer
for bits:
>>> bits = 2
>>> for i in ibin(2, 'all'):
... print(i)
(0, 0)
(0, 1)
(1, 0)
(1, 1)
If a bit string is desired of a given length, use str=True:
>>> n = 123
>>> bits = 10
>>> ibin(n, bits, str=True)
'0001111011'
>>> ibin(n, bits, str=True)[::-1] # small bits left
'1101111000'
>>> list(ibin(3, 'all', str=True))
['000', '001', '010', '011', '100', '101', '110', '111']
"""
if not str:
try:
bits = as_int(bits)
return [1 if i == "1" else 0 for i in bin(n)[2:].rjust(bits, "0")]
except ValueError:
return variations(list(range(2)), n, repetition=True)
else:
try:
bits = as_int(bits)
return bin(n)[2:].rjust(bits, "0")
except ValueError:
return (bin(i)[2:].rjust(n, "0") for i in range(2**n))
def variations(seq, n, repetition=False):
"""Returns a generator of the n-sized variations of ``seq`` (size N).
``repetition`` controls whether items in ``seq`` can appear more than once;
Examples
========
variations(seq, n) will return N! / (N - n)! permutations without
repetition of seq's elements:
>>> from sympy.utilities.iterables import variations
>>> list(variations([1, 2], 2))
[(1, 2), (2, 1)]
variations(seq, n, True) will return the N**n permutations obtained
by allowing repetition of elements:
>>> list(variations([1, 2], 2, repetition=True))
[(1, 1), (1, 2), (2, 1), (2, 2)]
If you ask for more items than are in the set you get the empty set unless
you allow repetitions:
>>> list(variations([0, 1], 3, repetition=False))
[]
>>> list(variations([0, 1], 3, repetition=True))[:4]
[(0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1)]
See Also
========
sympy.core.compatibility.permutations
sympy.core.compatibility.product
"""
if not repetition:
seq = tuple(seq)
if len(seq) < n:
return
for i in permutations(seq, n):
yield i
else:
if n == 0:
yield ()
else:
for i in product(seq, repeat=n):
yield i
def subsets(seq, k=None, repetition=False):
"""Generates all k-subsets (combinations) from an n-element set, seq.
A k-subset of an n-element set is any subset of length exactly k. The
number of k-subsets of an n-element set is given by binomial(n, k),
whereas there are 2**n subsets all together. If k is None then all
2**n subsets will be returned from shortest to longest.
Examples
========
>>> from sympy.utilities.iterables import subsets
subsets(seq, k) will return the n!/k!/(n - k)! k-subsets (combinations)
without repetition, i.e. once an item has been removed, it can no
longer be "taken":
>>> list(subsets([1, 2], 2))
[(1, 2)]
>>> list(subsets([1, 2]))
[(), (1,), (2,), (1, 2)]
>>> list(subsets([1, 2, 3], 2))
[(1, 2), (1, 3), (2, 3)]
subsets(seq, k, repetition=True) will return the (n - 1 + k)!/k!/(n - 1)!
combinations *with* repetition:
>>> list(subsets([1, 2], 2, repetition=True))
[(1, 1), (1, 2), (2, 2)]
If you ask for more items than are in the set you get the empty set unless
you allow repetitions:
>>> list(subsets([0, 1], 3, repetition=False))
[]
>>> list(subsets([0, 1], 3, repetition=True))
[(0, 0, 0), (0, 0, 1), (0, 1, 1), (1, 1, 1)]
"""
if k is None:
for k in range(len(seq) + 1):
for i in subsets(seq, k, repetition):
yield i
else:
if not repetition:
for i in combinations(seq, k):
yield i
else:
for i in combinations_with_replacement(seq, k):
yield i
def filter_symbols(iterator, exclude):
"""
Only yield elements from `iterator` that do not occur in `exclude`.
Parameters
==========
iterator : iterable
iterator to take elements from
exclude : iterable
elements to exclude
Returns
=======
iterator : iterator
filtered iterator
"""
exclude = set(exclude)
for s in iterator:
if s not in exclude:
yield s
def numbered_symbols(prefix='x', cls=None, start=0, exclude=[], *args, **assumptions):
"""
Generate an infinite stream of Symbols consisting of a prefix and
increasing subscripts provided that they do not occur in `exclude`.
Parameters
==========
prefix : str, optional
The prefix to use. By default, this function will generate symbols of
the form "x0", "x1", etc.
cls : class, optional
The class to use. By default, it uses Symbol, but you can also use Wild or Dummy.
start : int, optional
The start number. By default, it is 0.
Returns
=======
sym : Symbol
The subscripted symbols.
"""
exclude = set(exclude or [])
if cls is None:
# We can't just make the default cls=Symbol because it isn't
# imported yet.
from sympy import Symbol
cls = Symbol
while True:
name = '%s%s' % (prefix, start)
s = cls(name, *args, **assumptions)
if s not in exclude:
yield s
start += 1
def capture(func):
"""Return the printed output of func().
`func` should be a function without arguments that produces output with
print statements.
>>> from sympy.utilities.iterables import capture
>>> from sympy import pprint
>>> from sympy.abc import x
>>> def foo():
... print('hello world!')
...
>>> 'hello' in capture(foo) # foo, not foo()
True
>>> capture(lambda: pprint(2/x))
'2\\n-\\nx\\n'
"""
from sympy.core.compatibility import StringIO
import sys
stdout = sys.stdout
sys.stdout = file = StringIO()
try:
func()
finally:
sys.stdout = stdout
return file.getvalue()
def sift(seq, keyfunc, binary=False):
"""
Sift the sequence, ``seq`` according to ``keyfunc``.
OUTPUT: When binary is False (default), the output is a dictionary
where elements of ``seq`` are stored in a list keyed to the value
of keyfunc for that element. If ``binary`` is True then a tuple
with lists ``T`` and ``F`` are returned where ``T`` is a list
containing elements of seq for which ``keyfunc`` was True and
``F`` containing those elements for which ``keyfunc`` was False;
a ValueError is raised if the ``keyfunc`` is not binary.
Examples
========
>>> from sympy.utilities import sift
>>> from sympy.abc import x, y
>>> from sympy import sqrt, exp, pi, Tuple
>>> sift(range(5), lambda x: x % 2)
{0: [0, 2, 4], 1: [1, 3]}
sift() returns a defaultdict() object, so any key that has no matches will
give [].
>>> sift([x], lambda x: x.is_commutative)
{True: [x]}
>>> _[False]
[]
Sometimes you won't know how many keys you will get:
>>> sift([sqrt(x), exp(x), (y**x)**2],
... lambda x: x.as_base_exp()[0])
{E: [exp(x)], x: [sqrt(x)], y: [y**(2*x)]}
Sometimes you expect the results to be binary; the
results can be unpacked by setting ``binary`` to True:
>>> sift(range(4), lambda x: x % 2, binary=True)
([1, 3], [0, 2])
>>> sift(Tuple(1, pi), lambda x: x.is_rational, binary=True)
([1], [pi])
A ValueError is raised if the predicate was not actually binary
(which is a good test for the logic where sifting is used and
binary results were expected):
>>> unknown = exp(1) - pi # the rationality of this is unknown
>>> args = Tuple(1, pi, unknown)
>>> sift(args, lambda x: x.is_rational, binary=True)
Traceback (most recent call last):
...
ValueError: keyfunc gave non-binary output
The non-binary sifting shows that there were 3 keys generated:
>>> set(sift(args, lambda x: x.is_rational).keys())
{None, False, True}
If you need to sort the sifted items it might be better to use
``ordered`` which can economically apply multiple sort keys
to a squence while sorting.
See Also
========
ordered
"""
if not binary:
m = defaultdict(list)
for i in seq:
m[keyfunc(i)].append(i)
return m
sift = F, T = [], []
for i in seq:
try:
sift[keyfunc(i)].append(i)
except (IndexError, TypeError):
raise ValueError('keyfunc gave non-binary output')
return T, F
def take(iter, n):
"""Return ``n`` items from ``iter`` iterator. """
return [ value for _, value in zip(range(n), iter) ]
def dict_merge(*dicts):
"""Merge dictionaries into a single dictionary. """
merged = {}
for dict in dicts:
merged.update(dict)
return merged
def common_prefix(*seqs):
"""Return the subsequence that is a common start of sequences in ``seqs``.
>>> from sympy.utilities.iterables import common_prefix
>>> common_prefix(list(range(3)))
[0, 1, 2]
>>> common_prefix(list(range(3)), list(range(4)))
[0, 1, 2]
>>> common_prefix([1, 2, 3], [1, 2, 5])
[1, 2]
>>> common_prefix([1, 2, 3], [1, 3, 5])
[1]
"""
if any(not s for s in seqs):
return []
elif len(seqs) == 1:
return seqs[0]
i = 0
for i in range(min(len(s) for s in seqs)):
if not all(seqs[j][i] == seqs[0][i] for j in range(len(seqs))):
break
else:
i += 1
return seqs[0][:i]
def common_suffix(*seqs):
"""Return the subsequence that is a common ending of sequences in ``seqs``.
>>> from sympy.utilities.iterables import common_suffix
>>> common_suffix(list(range(3)))
[0, 1, 2]
>>> common_suffix(list(range(3)), list(range(4)))
[]
>>> common_suffix([1, 2, 3], [9, 2, 3])
[2, 3]
>>> common_suffix([1, 2, 3], [9, 7, 3])
[3]
"""
if any(not s for s in seqs):
return []
elif len(seqs) == 1:
return seqs[0]
i = 0
for i in range(-1, -min(len(s) for s in seqs) - 1, -1):
if not all(seqs[j][i] == seqs[0][i] for j in range(len(seqs))):
break
else:
i -= 1
if i == -1:
return []
else:
return seqs[0][i + 1:]
def prefixes(seq):
"""
Generate all prefixes of a sequence.
Examples
========
>>> from sympy.utilities.iterables import prefixes
>>> list(prefixes([1,2,3,4]))
[[1], [1, 2], [1, 2, 3], [1, 2, 3, 4]]
"""
n = len(seq)
for i in range(n):
yield seq[:i + 1]
def postfixes(seq):
"""
Generate all postfixes of a sequence.
Examples
========
>>> from sympy.utilities.iterables import postfixes
>>> list(postfixes([1,2,3,4]))
[[4], [3, 4], [2, 3, 4], [1, 2, 3, 4]]
"""
n = len(seq)
for i in range(n):
yield seq[n - i - 1:]
def topological_sort(graph, key=None):
r"""
Topological sort of graph's vertices.
Parameters
==========
``graph`` : ``tuple[list, list[tuple[T, T]]``
A tuple consisting of a list of vertices and a list of edges of
a graph to be sorted topologically.
``key`` : ``callable[T]`` (optional)
Ordering key for vertices on the same level. By default the natural
(e.g. lexicographic) ordering is used (in this case the base type
must implement ordering relations).
Examples
========
Consider a graph::
+---+ +---+ +---+
| 7 |\ | 5 | | 3 |
+---+ \ +---+ +---+
| _\___/ ____ _/ |
| / \___/ \ / |
V V V V |
+----+ +---+ |
| 11 | | 8 | |
+----+ +---+ |
| | \____ ___/ _ |
| \ \ / / \ |
V \ V V / V V
+---+ \ +---+ | +----+
| 2 | | | 9 | | | 10 |
+---+ | +---+ | +----+
\________/
where vertices are integers. This graph can be encoded using
elementary Python's data structures as follows::
>>> V = [2, 3, 5, 7, 8, 9, 10, 11]
>>> E = [(7, 11), (7, 8), (5, 11), (3, 8), (3, 10),
... (11, 2), (11, 9), (11, 10), (8, 9)]
To compute a topological sort for graph ``(V, E)`` issue::
>>> from sympy.utilities.iterables import topological_sort
>>> topological_sort((V, E))
[3, 5, 7, 8, 11, 2, 9, 10]
If specific tie breaking approach is needed, use ``key`` parameter::
>>> topological_sort((V, E), key=lambda v: -v)
[7, 5, 11, 3, 10, 8, 9, 2]
Only acyclic graphs can be sorted. If the input graph has a cycle,
then :py:exc:`ValueError` will be raised::
>>> topological_sort((V, E + [(10, 7)]))
Traceback (most recent call last):
...
ValueError: cycle detected
.. seealso:: https://en.wikipedia.org/wiki/Topological_sorting
"""
V, E = graph
L = []
S = set(V)
E = list(E)
for v, u in E:
S.discard(u)
if key is None:
key = lambda value: value
S = sorted(S, key=key, reverse=True)
while S:
node = S.pop()
L.append(node)
for u, v in list(E):
if u == node:
E.remove((u, v))
for _u, _v in E:
if v == _v:
break
else:
kv = key(v)
for i, s in enumerate(S):
ks = key(s)
if kv > ks:
S.insert(i, v)
break
else:
S.append(v)
if E:
raise ValueError("cycle detected")
else:
return L
def rotate_left(x, y):
"""
Left rotates a list x by the number of steps specified
in y.
Examples
========
>>> from sympy.utilities.iterables import rotate_left
>>> a = [0, 1, 2]
>>> rotate_left(a, 1)
[1, 2, 0]
"""
if len(x) == 0:
return []
y = y % len(x)
return x[y:] + x[:y]
def rotate_right(x, y):
"""
Right rotates a list x by the number of steps specified
in y.
Examples
========
>>> from sympy.utilities.iterables import rotate_right
>>> a = [0, 1, 2]
>>> rotate_right(a, 1)
[2, 0, 1]
"""
if len(x) == 0:
return []
y = len(x) - y % len(x)
return x[y:] + x[:y]
def least_rotation(x):
'''
Returns the number of steps of left rotation required to
obtain lexicographically minimal string/list/tuple, etc.
Examples
========
>>> from sympy.utilities.iterables import least_rotation, rotate_left
>>> a = [3, 1, 5, 1, 2]
>>> least_rotation(a)
3
>>> rotate_left(a, _)
[1, 2, 3, 1, 5]
.. seealso:: https://en.wikipedia.org/wiki/Lexicographically_minimal_string_rotation
'''
S = x + x # Concatenate string to it self to avoid modular arithmetic
f = [-1] * len(S) # Failure function
k = 0 # Least rotation of string found so far
for j in range(1,len(S)):
sj = S[j]
i = f[j-k-1]
while i != -1 and sj != S[k+i+1]:
if sj < S[k+i+1]:
k = j-i-1
i = f[i]
if sj != S[k+i+1]:
if sj < S[k]:
k = j
f[j-k] = -1
else:
f[j-k] = i+1
return k
def multiset_combinations(m, n, g=None):
"""
Return the unique combinations of size ``n`` from multiset ``m``.
Examples
========
>>> from sympy.utilities.iterables import multiset_combinations
>>> from itertools import combinations
>>> [''.join(i) for i in multiset_combinations('baby', 3)]
['abb', 'aby', 'bby']
>>> def count(f, s): return len(list(f(s, 3)))
The number of combinations depends on the number of letters; the
number of unique combinations depends on how the letters are
repeated.
>>> s1 = 'abracadabra'
>>> s2 = 'banana tree'
>>> count(combinations, s1), count(multiset_combinations, s1)
(165, 23)
>>> count(combinations, s2), count(multiset_combinations, s2)
(165, 54)
"""
if g is None:
if type(m) is dict:
if n > sum(m.values()):
return
g = [[k, m[k]] for k in ordered(m)]
else:
m = list(m)
if n > len(m):
return
try:
m = multiset(m)
g = [(k, m[k]) for k in ordered(m)]
except TypeError:
m = list(ordered(m))
g = [list(i) for i in group(m, multiple=False)]
del m
if sum(v for k, v in g) < n or not n:
yield []
else:
for i, (k, v) in enumerate(g):
if v >= n:
yield [k]*n
v = n - 1
for v in range(min(n, v), 0, -1):
for j in multiset_combinations(None, n - v, g[i + 1:]):
rv = [k]*v + j
if len(rv) == n:
yield rv
def multiset_permutations(m, size=None, g=None):
"""
Return the unique permutations of multiset ``m``.
Examples
========
>>> from sympy.utilities.iterables import multiset_permutations
>>> from sympy import factorial
>>> [''.join(i) for i in multiset_permutations('aab')]
['aab', 'aba', 'baa']
>>> factorial(len('banana'))
720
>>> len(list(multiset_permutations('banana')))
60
"""
if g is None:
if type(m) is dict:
g = [[k, m[k]] for k in ordered(m)]
else:
m = list(ordered(m))
g = [list(i) for i in group(m, multiple=False)]
del m
do = [gi for gi in g if gi[1] > 0]
SUM = sum([gi[1] for gi in do])
if not do or size is not None and (size > SUM or size < 1):
if size < 1:
yield []
return
elif size == 1:
for k, v in do:
yield [k]
elif len(do) == 1:
k, v = do[0]
v = v if size is None else (size if size <= v else 0)
yield [k for i in range(v)]
elif all(v == 1 for k, v in do):
for p in permutations([k for k, v in do], size):
yield list(p)
else:
size = size if size is not None else SUM
for i, (k, v) in enumerate(do):
do[i][1] -= 1
for j in multiset_permutations(None, size - 1, do):
if j:
yield [k] + j
do[i][1] += 1
def _partition(seq, vector, m=None):
"""
Return the partition of seq as specified by the partition vector.
Examples
========
>>> from sympy.utilities.iterables import _partition
>>> _partition('abcde', [1, 0, 1, 2, 0])
[['b', 'e'], ['a', 'c'], ['d']]
Specifying the number of bins in the partition is optional:
>>> _partition('abcde', [1, 0, 1, 2, 0], 3)
[['b', 'e'], ['a', 'c'], ['d']]
The output of _set_partitions can be passed as follows:
>>> output = (3, [1, 0, 1, 2, 0])
>>> _partition('abcde', *output)
[['b', 'e'], ['a', 'c'], ['d']]
See Also
========
combinatorics.partitions.Partition.from_rgs()
"""
if m is None:
m = max(vector) + 1
elif type(vector) is int: # entered as m, vector
vector, m = m, vector
p = [[] for i in range(m)]
for i, v in enumerate(vector):
p[v].append(seq[i])
return p
def _set_partitions(n):
"""Cycle through all partions of n elements, yielding the
current number of partitions, ``m``, and a mutable list, ``q``
such that element[i] is in part q[i] of the partition.
NOTE: ``q`` is modified in place and generally should not be changed
between function calls.
Examples
========
>>> from sympy.utilities.iterables import _set_partitions, _partition
>>> for m, q in _set_partitions(3):
... print('%s %s %s' % (m, q, _partition('abc', q, m)))
1 [0, 0, 0] [['a', 'b', 'c']]
2 [0, 0, 1] [['a', 'b'], ['c']]
2 [0, 1, 0] [['a', 'c'], ['b']]
2 [0, 1, 1] [['a'], ['b', 'c']]
3 [0, 1, 2] [['a'], ['b'], ['c']]
Notes
=====
This algorithm is similar to, and solves the same problem as,
Algorithm 7.2.1.5H, from volume 4A of Knuth's The Art of Computer
Programming. Knuth uses the term "restricted growth string" where
this code refers to a "partition vector". In each case, the meaning is
the same: the value in the ith element of the vector specifies to
which part the ith set element is to be assigned.
At the lowest level, this code implements an n-digit big-endian
counter (stored in the array q) which is incremented (with carries) to
get the next partition in the sequence. A special twist is that a
digit is constrained to be at most one greater than the maximum of all
the digits to the left of it. The array p maintains this maximum, so
that the code can efficiently decide when a digit can be incremented
in place or whether it needs to be reset to 0 and trigger a carry to
the next digit. The enumeration starts with all the digits 0 (which
corresponds to all the set elements being assigned to the same 0th
part), and ends with 0123...n, which corresponds to each set element
being assigned to a different, singleton, part.
This routine was rewritten to use 0-based lists while trying to
preserve the beauty and efficiency of the original algorithm.
Reference
=========
Nijenhuis, Albert and Wilf, Herbert. (1978) Combinatorial Algorithms,
2nd Ed, p 91, algorithm "nexequ". Available online from
https://www.math.upenn.edu/~wilf/website/CombAlgDownld.html (viewed
November 17, 2012).
"""
p = [0]*n
q = [0]*n
nc = 1
yield nc, q
while nc != n:
m = n
while 1:
m -= 1
i = q[m]
if p[i] != 1:
break
q[m] = 0
i += 1
q[m] = i
m += 1
nc += m - n
p[0] += n - m
if i == nc:
p[nc] = 0
nc += 1
p[i - 1] -= 1
p[i] += 1
yield nc, q
def multiset_partitions(multiset, m=None):
"""
Return unique partitions of the given multiset (in list form).
If ``m`` is None, all multisets will be returned, otherwise only
partitions with ``m`` parts will be returned.
If ``multiset`` is an integer, a range [0, 1, ..., multiset - 1]
will be supplied.
Examples
========
>>> from sympy.utilities.iterables import multiset_partitions
>>> list(multiset_partitions([1, 2, 3, 4], 2))
[[[1, 2, 3], [4]], [[1, 2, 4], [3]], [[1, 2], [3, 4]],
[[1, 3, 4], [2]], [[1, 3], [2, 4]], [[1, 4], [2, 3]],
[[1], [2, 3, 4]]]
>>> list(multiset_partitions([1, 2, 3, 4], 1))
[[[1, 2, 3, 4]]]
Only unique partitions are returned and these will be returned in a
canonical order regardless of the order of the input:
>>> a = [1, 2, 2, 1]
>>> ans = list(multiset_partitions(a, 2))
>>> a.sort()
>>> list(multiset_partitions(a, 2)) == ans
True
>>> a = range(3, 1, -1)
>>> (list(multiset_partitions(a)) ==
... list(multiset_partitions(sorted(a))))
True
If m is omitted then all partitions will be returned:
>>> list(multiset_partitions([1, 1, 2]))
[[[1, 1, 2]], [[1, 1], [2]], [[1, 2], [1]], [[1], [1], [2]]]
>>> list(multiset_partitions([1]*3))
[[[1, 1, 1]], [[1], [1, 1]], [[1], [1], [1]]]
Counting
========
The number of partitions of a set is given by the bell number:
>>> from sympy import bell
>>> len(list(multiset_partitions(5))) == bell(5) == 52
True
The number of partitions of length k from a set of size n is given by the
Stirling Number of the 2nd kind:
>>> def S2(n, k):
... from sympy import Dummy, binomial, factorial, Sum
... if k > n:
... return 0
... j = Dummy()
... arg = (-1)**(k-j)*j**n*binomial(k,j)
... return 1/factorial(k)*Sum(arg,(j,0,k)).doit()
...
>>> S2(5, 2) == len(list(multiset_partitions(5, 2))) == 15
True
These comments on counting apply to *sets*, not multisets.
Notes
=====
When all the elements are the same in the multiset, the order
of the returned partitions is determined by the ``partitions``
routine. If one is counting partitions then it is better to use
the ``nT`` function.
See Also
========
partitions
sympy.combinatorics.partitions.Partition
sympy.combinatorics.partitions.IntegerPartition
sympy.functions.combinatorial.numbers.nT
"""
# This function looks at the supplied input and dispatches to
# several special-case routines as they apply.
if type(multiset) is int:
n = multiset
if m and m > n:
return
multiset = list(range(n))
if m == 1:
yield [multiset[:]]
return
# If m is not None, it can sometimes be faster to use
# MultisetPartitionTraverser.enum_range() even for inputs
# which are sets. Since the _set_partitions code is quite
# fast, this is only advantageous when the overall set
# partitions outnumber those with the desired number of parts
# by a large factor. (At least 60.) Such a switch is not
# currently implemented.
for nc, q in _set_partitions(n):
if m is None or nc == m:
rv = [[] for i in range(nc)]
for i in range(n):
rv[q[i]].append(multiset[i])
yield rv
return
if len(multiset) == 1 and type(multiset) is str:
multiset = [multiset]
if not has_variety(multiset):
# Only one component, repeated n times. The resulting
# partitions correspond to partitions of integer n.
n = len(multiset)
if m and m > n:
return
if m == 1:
yield [multiset[:]]
return
x = multiset[:1]
for size, p in partitions(n, m, size=True):
if m is None or size == m:
rv = []
for k in sorted(p):
rv.extend([x*k]*p[k])
yield rv
else:
multiset = list(ordered(multiset))
n = len(multiset)
if m and m > n:
return
if m == 1:
yield [multiset[:]]
return
# Split the information of the multiset into two lists -
# one of the elements themselves, and one (of the same length)
# giving the number of repeats for the corresponding element.
elements, multiplicities = zip(*group(multiset, False))
if len(elements) < len(multiset):
# General case - multiset with more than one distinct element
# and at least one element repeated more than once.
if m:
mpt = MultisetPartitionTraverser()
for state in mpt.enum_range(multiplicities, m-1, m):
yield list_visitor(state, elements)
else:
for state in multiset_partitions_taocp(multiplicities):
yield list_visitor(state, elements)
else:
# Set partitions case - no repeated elements. Pretty much
# same as int argument case above, with same possible, but
# currently unimplemented optimization for some cases when
# m is not None
for nc, q in _set_partitions(n):
if m is None or nc == m:
rv = [[] for i in range(nc)]
for i in range(n):
rv[q[i]].append(i)
yield [[multiset[j] for j in i] for i in rv]
def partitions(n, m=None, k=None, size=False):
"""Generate all partitions of positive integer, n.
Parameters
==========
``m`` : integer (default gives partitions of all sizes)
limits number of parts in partition (mnemonic: m, maximum parts)
``k`` : integer (default gives partitions number from 1 through n)
limits the numbers that are kept in the partition (mnemonic: k, keys)
``size`` : bool (default False, only partition is returned)
when ``True`` then (M, P) is returned where M is the sum of the
multiplicities and P is the generated partition.
Each partition is represented as a dictionary, mapping an integer
to the number of copies of that integer in the partition. For example,
the first partition of 4 returned is {4: 1}, "4: one of them".
Examples
========
>>> from sympy.utilities.iterables import partitions
The numbers appearing in the partition (the key of the returned dict)
are limited with k:
>>> for p in partitions(6, k=2): # doctest: +SKIP
... print(p)
{2: 3}
{1: 2, 2: 2}
{1: 4, 2: 1}
{1: 6}
The maximum number of parts in the partition (the sum of the values in
the returned dict) are limited with m (default value, None, gives
partitions from 1 through n):
>>> for p in partitions(6, m=2): # doctest: +SKIP
... print(p)
...
{6: 1}
{1: 1, 5: 1}
{2: 1, 4: 1}
{3: 2}
Note that the _same_ dictionary object is returned each time.
This is for speed: generating each partition goes quickly,
taking constant time, independent of n.
>>> [p for p in partitions(6, k=2)]
[{1: 6}, {1: 6}, {1: 6}, {1: 6}]
If you want to build a list of the returned dictionaries then
make a copy of them:
>>> [p.copy() for p in partitions(6, k=2)] # doctest: +SKIP
[{2: 3}, {1: 2, 2: 2}, {1: 4, 2: 1}, {1: 6}]
>>> [(M, p.copy()) for M, p in partitions(6, k=2, size=True)] # doctest: +SKIP
[(3, {2: 3}), (4, {1: 2, 2: 2}), (5, {1: 4, 2: 1}), (6, {1: 6})]
Reference:
modified from Tim Peter's version to allow for k and m values:
code.activestate.com/recipes/218332-generator-for-integer-partitions/
See Also
========
sympy.combinatorics.partitions.Partition
sympy.combinatorics.partitions.IntegerPartition
"""
if (
n <= 0 or
m is not None and m < 1 or
k is not None and k < 1 or
m and k and m*k < n):
# the empty set is the only way to handle these inputs
# and returning {} to represent it is consistent with
# the counting convention, e.g. nT(0) == 1.
if size:
yield 0, {}
else:
yield {}
return
if m is None:
m = n
else:
m = min(m, n)
if n == 0:
if size:
yield 1, {0: 1}
else:
yield {0: 1}
return
k = min(k or n, n)
n, m, k = as_int(n), as_int(m), as_int(k)
q, r = divmod(n, k)
ms = {k: q}
keys = [k] # ms.keys(), from largest to smallest
if r:
ms[r] = 1
keys.append(r)
room = m - q - bool(r)
if size:
yield sum(ms.values()), ms
else:
yield ms
while keys != [1]:
# Reuse any 1's.
if keys[-1] == 1:
del keys[-1]
reuse = ms.pop(1)
room += reuse
else:
reuse = 0
while 1:
# Let i be the smallest key larger than 1. Reuse one
# instance of i.
i = keys[-1]
newcount = ms[i] = ms[i] - 1
reuse += i
if newcount == 0:
del keys[-1], ms[i]
room += 1
# Break the remainder into pieces of size i-1.
i -= 1
q, r = divmod(reuse, i)
need = q + bool(r)
if need > room:
if not keys:
return
continue
ms[i] = q
keys.append(i)
if r:
ms[r] = 1
keys.append(r)
break
room -= need
if size:
yield sum(ms.values()), ms
else:
yield ms
def ordered_partitions(n, m=None, sort=True):
"""Generates ordered partitions of integer ``n``.
Parameters
==========
``m`` : integer (default gives partitions of all sizes) else only
those with size m. In addition, if ``m`` is not None then
partitions are generated *in place* (see examples).
``sort`` : bool (default True) controls whether partitions are
returned in sorted order when ``m`` is not None; when False,
the partitions are returned as fast as possible with elements
sorted, but when m|n the partitions will not be in
ascending lexicographical order.
Examples
========
>>> from sympy.utilities.iterables import ordered_partitions
All partitions of 5 in ascending lexicographical:
>>> for p in ordered_partitions(5):
... print(p)
[1, 1, 1, 1, 1]
[1, 1, 1, 2]
[1, 1, 3]
[1, 2, 2]
[1, 4]
[2, 3]
[5]
Only partitions of 5 with two parts:
>>> for p in ordered_partitions(5, 2):
... print(p)
[1, 4]
[2, 3]
When ``m`` is given, a given list objects will be used more than
once for speed reasons so you will not see the correct partitions
unless you make a copy of each as it is generated:
>>> [p for p in ordered_partitions(7, 3)]
[[1, 1, 1], [1, 1, 1], [1, 1, 1], [2, 2, 2]]
>>> [list(p) for p in ordered_partitions(7, 3)]
[[1, 1, 5], [1, 2, 4], [1, 3, 3], [2, 2, 3]]
When ``n`` is a multiple of ``m``, the elements are still sorted
but the partitions themselves will be *unordered* if sort is False;
the default is to return them in ascending lexicographical order.
>>> for p in ordered_partitions(6, 2):
... print(p)
[1, 5]
[2, 4]
[3, 3]
But if speed is more important than ordering, sort can be set to
False:
>>> for p in ordered_partitions(6, 2, sort=False):
... print(p)
[1, 5]
[3, 3]
[2, 4]
References
==========
.. [1] Generating Integer Partitions, [online],
Available: https://jeromekelleher.net/generating-integer-partitions.html
.. [2] Jerome Kelleher and Barry O'Sullivan, "Generating All
Partitions: A Comparison Of Two Encodings", [online],
Available: https://arxiv.org/pdf/0909.2331v2.pdf
"""
if n < 1 or m is not None and m < 1:
# the empty set is the only way to handle these inputs
# and returning {} to represent it is consistent with
# the counting convention, e.g. nT(0) == 1.
yield []
return
if m is None:
# The list `a`'s leading elements contain the partition in which
# y is the biggest element and x is either the same as y or the
# 2nd largest element; v and w are adjacent element indices
# to which x and y are being assigned, respectively.
a = [1]*n
y = -1
v = n
while v > 0:
v -= 1
x = a[v] + 1
while y >= 2 * x:
a[v] = x
y -= x
v += 1
w = v + 1
while x <= y:
a[v] = x
a[w] = y
yield a[:w + 1]
x += 1
y -= 1
a[v] = x + y
y = a[v] - 1
yield a[:w]
elif m == 1:
yield [n]
elif n == m:
yield [1]*n
else:
# recursively generate partitions of size m
for b in range(1, n//m + 1):
a = [b]*m
x = n - b*m
if not x:
if sort:
yield a
elif not sort and x <= m:
for ax in ordered_partitions(x, sort=False):
mi = len(ax)
a[-mi:] = [i + b for i in ax]
yield a
a[-mi:] = [b]*mi
else:
for mi in range(1, m):
for ax in ordered_partitions(x, mi, sort=True):
a[-mi:] = [i + b for i in ax]
yield a
a[-mi:] = [b]*mi
def binary_partitions(n):
"""
Generates the binary partition of n.
A binary partition consists only of numbers that are
powers of two. Each step reduces a 2**(k+1) to 2**k and
2**k. Thus 16 is converted to 8 and 8.
Reference: TAOCP 4, section 7.2.1.5, problem 64
Examples
========
>>> from sympy.utilities.iterables import binary_partitions
>>> for i in binary_partitions(5):
... print(i)
...
[4, 1]
[2, 2, 1]
[2, 1, 1, 1]
[1, 1, 1, 1, 1]
"""
from math import ceil, log
pow = int(2**(ceil(log(n, 2))))
sum = 0
partition = []
while pow:
if sum + pow <= n:
partition.append(pow)
sum += pow
pow >>= 1
last_num = len(partition) - 1 - (n & 1)
while last_num >= 0:
yield partition
if partition[last_num] == 2:
partition[last_num] = 1
partition.append(1)
last_num -= 1
continue
partition.append(1)
partition[last_num] >>= 1
x = partition[last_num + 1] = partition[last_num]
last_num += 1
while x > 1:
if x <= len(partition) - last_num - 1:
del partition[-x + 1:]
last_num += 1
partition[last_num] = x
else:
x >>= 1
yield [1]*n
def has_dups(seq):
"""Return True if there are any duplicate elements in ``seq``.
Examples
========
>>> from sympy.utilities.iterables import has_dups
>>> from sympy import Dict, Set
>>> has_dups((1, 2, 1))
True
>>> has_dups(range(3))
False
>>> all(has_dups(c) is False for c in (set(), Set(), dict(), Dict()))
True
"""
from sympy.core.containers import Dict
from sympy.sets.sets import Set
if isinstance(seq, (dict, set, Dict, Set)):
return False
uniq = set()
return any(True for s in seq if s in uniq or uniq.add(s))
def has_variety(seq):
"""Return True if there are any different elements in ``seq``.
Examples
========
>>> from sympy.utilities.iterables import has_variety
>>> has_variety((1, 2, 1))
True
>>> has_variety((1, 1, 1))
False
"""
for i, s in enumerate(seq):
if i == 0:
sentinel = s
else:
if s != sentinel:
return True
return False
def uniq(seq, result=None):
"""
Yield unique elements from ``seq`` as an iterator. The second
parameter ``result`` is used internally; it is not necessary to pass
anything for this.
Examples
========
>>> from sympy.utilities.iterables import uniq
>>> dat = [1, 4, 1, 5, 4, 2, 1, 2]
>>> type(uniq(dat)) in (list, tuple)
False
>>> list(uniq(dat))
[1, 4, 5, 2]
>>> list(uniq(x for x in dat))
[1, 4, 5, 2]
>>> list(uniq([[1], [2, 1], [1]]))
[[1], [2, 1]]
"""
try:
seen = set()
result = result or []
for i, s in enumerate(seq):
if not (s in seen or seen.add(s)):
yield s
except TypeError:
if s not in result:
yield s
result.append(s)
if hasattr(seq, '__getitem__'):
for s in uniq(seq[i + 1:], result):
yield s
else:
for s in uniq(seq, result):
yield s
def generate_bell(n):
"""Return permutations of [0, 1, ..., n - 1] such that each permutation
differs from the last by the exchange of a single pair of neighbors.
The ``n!`` permutations are returned as an iterator. In order to obtain
the next permutation from a random starting permutation, use the
``next_trotterjohnson`` method of the Permutation class (which generates
the same sequence in a different manner).
Examples
========
>>> from itertools import permutations
>>> from sympy.utilities.iterables import generate_bell
>>> from sympy import zeros, Matrix
This is the sort of permutation used in the ringing of physical bells,
and does not produce permutations in lexicographical order. Rather, the
permutations differ from each other by exactly one inversion, and the
position at which the swapping occurs varies periodically in a simple
fashion. Consider the first few permutations of 4 elements generated
by ``permutations`` and ``generate_bell``:
>>> list(permutations(range(4)))[:5]
[(0, 1, 2, 3), (0, 1, 3, 2), (0, 2, 1, 3), (0, 2, 3, 1), (0, 3, 1, 2)]
>>> list(generate_bell(4))[:5]
[(0, 1, 2, 3), (0, 1, 3, 2), (0, 3, 1, 2), (3, 0, 1, 2), (3, 0, 2, 1)]
Notice how the 2nd and 3rd lexicographical permutations have 3 elements
out of place whereas each "bell" permutation always has only two
elements out of place relative to the previous permutation (and so the
signature (+/-1) of a permutation is opposite of the signature of the
previous permutation).
How the position of inversion varies across the elements can be seen
by tracing out where the largest number appears in the permutations:
>>> m = zeros(4, 24)
>>> for i, p in enumerate(generate_bell(4)):
... m[:, i] = Matrix([j - 3 for j in list(p)]) # make largest zero
>>> m.print_nonzero('X')
[XXX XXXXXX XXXXXX XXX]
[XX XX XXXX XX XXXX XX XX]
[X XXXX XX XXXX XX XXXX X]
[ XXXXXX XXXXXX XXXXXX ]
See Also
========
sympy.combinatorics.Permutation.next_trotterjohnson
References
==========
* https://en.wikipedia.org/wiki/Method_ringing
* https://stackoverflow.com/questions/4856615/recursive-permutation/4857018
* http://programminggeeks.com/bell-algorithm-for-permutation/
* https://en.wikipedia.org/wiki/Steinhaus%E2%80%93Johnson%E2%80%93Trotter_algorithm
* Generating involutions, derangements, and relatives by ECO
Vincent Vajnovszki, DMTCS vol 1 issue 12, 2010
"""
n = as_int(n)
if n < 1:
raise ValueError('n must be a positive integer')
if n == 1:
yield (0,)
elif n == 2:
yield (0, 1)
yield (1, 0)
elif n == 3:
for li in [(0, 1, 2), (0, 2, 1), (2, 0, 1), (2, 1, 0), (1, 2, 0), (1, 0, 2)]:
yield li
else:
m = n - 1
op = [0] + [-1]*m
l = list(range(n))
while True:
yield tuple(l)
# find biggest element with op
big = None, -1 # idx, value
for i in range(n):
if op[i] and l[i] > big[1]:
big = i, l[i]
i, _ = big
if i is None:
break # there are no ops left
# swap it with neighbor in the indicated direction
j = i + op[i]
l[i], l[j] = l[j], l[i]
op[i], op[j] = op[j], op[i]
# if it landed at the end or if the neighbor in the same
# direction is bigger then turn off op
if j == 0 or j == m or l[j + op[j]] > l[j]:
op[j] = 0
# any element bigger to the left gets +1 op
for i in range(j):
if l[i] > l[j]:
op[i] = 1
# any element bigger to the right gets -1 op
for i in range(j + 1, n):
if l[i] > l[j]:
op[i] = -1
def generate_involutions(n):
"""
Generates involutions.
An involution is a permutation that when multiplied
by itself equals the identity permutation. In this
implementation the involutions are generated using
Fixed Points.
Alternatively, an involution can be considered as
a permutation that does not contain any cycles with
a length that is greater than two.
Reference:
http://mathworld.wolfram.com/PermutationInvolution.html
Examples
========
>>> from sympy.utilities.iterables import generate_involutions
>>> list(generate_involutions(3))
[(0, 1, 2), (0, 2, 1), (1, 0, 2), (2, 1, 0)]
>>> len(list(generate_involutions(4)))
10
"""
idx = list(range(n))
for p in permutations(idx):
for i in idx:
if p[p[i]] != i:
break
else:
yield p
def generate_derangements(perm):
"""
Routine to generate unique derangements.
TODO: This will be rewritten to use the
ECO operator approach once the permutations
branch is in master.
Examples
========
>>> from sympy.utilities.iterables import generate_derangements
>>> list(generate_derangements([0, 1, 2]))
[[1, 2, 0], [2, 0, 1]]
>>> list(generate_derangements([0, 1, 2, 3]))
[[1, 0, 3, 2], [1, 2, 3, 0], [1, 3, 0, 2], [2, 0, 3, 1], \
[2, 3, 0, 1], [2, 3, 1, 0], [3, 0, 1, 2], [3, 2, 0, 1], \
[3, 2, 1, 0]]
>>> list(generate_derangements([0, 1, 1]))
[]
See Also
========
sympy.functions.combinatorial.factorials.subfactorial
"""
p = multiset_permutations(perm)
indices = range(len(perm))
p0 = next(p)
for pi in p:
if all(pi[i] != p0[i] for i in indices):
yield pi
def necklaces(n, k, free=False):
"""
A routine to generate necklaces that may (free=True) or may not
(free=False) be turned over to be viewed. The "necklaces" returned
are comprised of ``n`` integers (beads) with ``k`` different
values (colors). Only unique necklaces are returned.
Examples
========
>>> from sympy.utilities.iterables import necklaces, bracelets
>>> def show(s, i):
... return ''.join(s[j] for j in i)
The "unrestricted necklace" is sometimes also referred to as a
"bracelet" (an object that can be turned over, a sequence that can
be reversed) and the term "necklace" is used to imply a sequence
that cannot be reversed. So ACB == ABC for a bracelet (rotate and
reverse) while the two are different for a necklace since rotation
alone cannot make the two sequences the same.
(mnemonic: Bracelets can be viewed Backwards, but Not Necklaces.)
>>> B = [show('ABC', i) for i in bracelets(3, 3)]
>>> N = [show('ABC', i) for i in necklaces(3, 3)]
>>> set(N) - set(B)
{'ACB'}
>>> list(necklaces(4, 2))
[(0, 0, 0, 0), (0, 0, 0, 1), (0, 0, 1, 1),
(0, 1, 0, 1), (0, 1, 1, 1), (1, 1, 1, 1)]
>>> [show('.o', i) for i in bracelets(4, 2)]
['....', '...o', '..oo', '.o.o', '.ooo', 'oooo']
References
==========
http://mathworld.wolfram.com/Necklace.html
"""
return uniq(minlex(i, directed=not free) for i in
variations(list(range(k)), n, repetition=True))
def bracelets(n, k):
"""Wrapper to necklaces to return a free (unrestricted) necklace."""
return necklaces(n, k, free=True)
def generate_oriented_forest(n):
"""
This algorithm generates oriented forests.
An oriented graph is a directed graph having no symmetric pair of directed
edges. A forest is an acyclic graph, i.e., it has no cycles. A forest can
also be described as a disjoint union of trees, which are graphs in which
any two vertices are connected by exactly one simple path.
Reference:
[1] T. Beyer and S.M. Hedetniemi: constant time generation of \
rooted trees, SIAM J. Computing Vol. 9, No. 4, November 1980
[2] https://stackoverflow.com/questions/1633833/oriented-forest-taocp-algorithm-in-python
Examples
========
>>> from sympy.utilities.iterables import generate_oriented_forest
>>> list(generate_oriented_forest(4))
[[0, 1, 2, 3], [0, 1, 2, 2], [0, 1, 2, 1], [0, 1, 2, 0], \
[0, 1, 1, 1], [0, 1, 1, 0], [0, 1, 0, 1], [0, 1, 0, 0], [0, 0, 0, 0]]
"""
P = list(range(-1, n))
while True:
yield P[1:]
if P[n] > 0:
P[n] = P[P[n]]
else:
for p in range(n - 1, 0, -1):
if P[p] != 0:
target = P[p] - 1
for q in range(p - 1, 0, -1):
if P[q] == target:
break
offset = p - q
for i in range(p, n + 1):
P[i] = P[i - offset]
break
else:
break
def minlex(seq, directed=True, is_set=False, small=None):
"""
Return a tuple where the smallest element appears first; if
``directed`` is True (default) then the order is preserved, otherwise
the sequence will be reversed if that gives a smaller ordering.
If every element appears only once then is_set can be set to True
for more efficient processing.
If the smallest element is known at the time of calling, it can be
passed and the calculation of the smallest element will be omitted.
Examples
========
>>> from sympy.combinatorics.polyhedron import minlex
>>> minlex((1, 2, 0))
(0, 1, 2)
>>> minlex((1, 0, 2))
(0, 2, 1)
>>> minlex((1, 0, 2), directed=False)
(0, 1, 2)
>>> minlex('11010011000', directed=True)
'00011010011'
>>> minlex('11010011000', directed=False)
'00011001011'
"""
is_str = isinstance(seq, str)
seq = list(seq)
if small is None:
small = min(seq, key=default_sort_key)
if is_set:
i = seq.index(small)
if not directed:
n = len(seq)
p = (i + 1) % n
m = (i - 1) % n
if default_sort_key(seq[p]) > default_sort_key(seq[m]):
seq = list(reversed(seq))
i = n - i - 1
if i:
seq = rotate_left(seq, i)
best = seq
else:
count = seq.count(small)
if count == 1 and directed:
best = rotate_left(seq, seq.index(small))
else:
# if not directed, and not a set, we can't just
# pass this off to minlex with is_set True since
# peeking at the neighbor may not be sufficient to
# make the decision so we continue...
best = seq
for i in range(count):
seq = rotate_left(seq, seq.index(small, count != 1))
if seq < best:
best = seq
# it's cheaper to rotate now rather than search
# again for these in reversed order so we test
# the reverse now
if not directed:
seq = rotate_left(seq, 1)
seq = list(reversed(seq))
if seq < best:
best = seq
seq = list(reversed(seq))
seq = rotate_right(seq, 1)
# common return
if is_str:
return ''.join(best)
return tuple(best)
def runs(seq, op=gt):
"""Group the sequence into lists in which successive elements
all compare the same with the comparison operator, ``op``:
op(seq[i + 1], seq[i]) is True from all elements in a run.
Examples
========
>>> from sympy.utilities.iterables import runs
>>> from operator import ge
>>> runs([0, 1, 2, 2, 1, 4, 3, 2, 2])
[[0, 1, 2], [2], [1, 4], [3], [2], [2]]
>>> runs([0, 1, 2, 2, 1, 4, 3, 2, 2], op=ge)
[[0, 1, 2, 2], [1, 4], [3], [2, 2]]
"""
cycles = []
seq = iter(seq)
try:
run = [next(seq)]
except StopIteration:
return []
while True:
try:
ei = next(seq)
except StopIteration:
break
if op(ei, run[-1]):
run.append(ei)
continue
else:
cycles.append(run)
run = [ei]
if run:
cycles.append(run)
return cycles
def kbins(l, k, ordered=None):
"""
Return sequence ``l`` partitioned into ``k`` bins.
Examples
========
>>> from sympy.utilities.iterables import kbins
The default is to give the items in the same order, but grouped
into k partitions without any reordering:
>>> from __future__ import print_function
>>> for p in kbins(list(range(5)), 2):
... print(p)
...
[[0], [1, 2, 3, 4]]
[[0, 1], [2, 3, 4]]
[[0, 1, 2], [3, 4]]
[[0, 1, 2, 3], [4]]
The ``ordered`` flag is either None (to give the simple partition
of the elements) or is a 2 digit integer indicating whether the order of
the bins and the order of the items in the bins matters. Given::
A = [[0], [1, 2]]
B = [[1, 2], [0]]
C = [[2, 1], [0]]
D = [[0], [2, 1]]
the following values for ``ordered`` have the shown meanings::
00 means A == B == C == D
01 means A == B
10 means A == D
11 means A == A
>>> for ordered in [None, 0, 1, 10, 11]:
... print('ordered = %s' % ordered)
... for p in kbins(list(range(3)), 2, ordered=ordered):
... print(' %s' % p)
...
ordered = None
[[0], [1, 2]]
[[0, 1], [2]]
ordered = 0
[[0, 1], [2]]
[[0, 2], [1]]
[[0], [1, 2]]
ordered = 1
[[0], [1, 2]]
[[0], [2, 1]]
[[1], [0, 2]]
[[1], [2, 0]]
[[2], [0, 1]]
[[2], [1, 0]]
ordered = 10
[[0, 1], [2]]
[[2], [0, 1]]
[[0, 2], [1]]
[[1], [0, 2]]
[[0], [1, 2]]
[[1, 2], [0]]
ordered = 11
[[0], [1, 2]]
[[0, 1], [2]]
[[0], [2, 1]]
[[0, 2], [1]]
[[1], [0, 2]]
[[1, 0], [2]]
[[1], [2, 0]]
[[1, 2], [0]]
[[2], [0, 1]]
[[2, 0], [1]]
[[2], [1, 0]]
[[2, 1], [0]]
See Also
========
partitions, multiset_partitions
"""
def partition(lista, bins):
# EnricoGiampieri's partition generator from
# https://stackoverflow.com/questions/13131491/
# partition-n-items-into-k-bins-in-python-lazily
if len(lista) == 1 or bins == 1:
yield [lista]
elif len(lista) > 1 and bins > 1:
for i in range(1, len(lista)):
for part in partition(lista[i:], bins - 1):
if len([lista[:i]] + part) == bins:
yield [lista[:i]] + part
if ordered is None:
for p in partition(l, k):
yield p
elif ordered == 11:
for pl in multiset_permutations(l):
pl = list(pl)
for p in partition(pl, k):
yield p
elif ordered == 00:
for p in multiset_partitions(l, k):
yield p
elif ordered == 10:
for p in multiset_partitions(l, k):
for perm in permutations(p):
yield list(perm)
elif ordered == 1:
for kgot, p in partitions(len(l), k, size=True):
if kgot != k:
continue
for li in multiset_permutations(l):
rv = []
i = j = 0
li = list(li)
for size, multiplicity in sorted(p.items()):
for m in range(multiplicity):
j = i + size
rv.append(li[i: j])
i = j
yield rv
else:
raise ValueError(
'ordered must be one of 00, 01, 10 or 11, not %s' % ordered)
def permute_signs(t):
"""Return iterator in which the signs of non-zero elements
of t are permuted.
Examples
========
>>> from sympy.utilities.iterables import permute_signs
>>> list(permute_signs((0, 1, 2)))
[(0, 1, 2), (0, -1, 2), (0, 1, -2), (0, -1, -2)]
"""
for signs in cartes(*[(1, -1)]*(len(t) - t.count(0))):
signs = list(signs)
yield type(t)([i*signs.pop() if i else i for i in t])
def signed_permutations(t):
"""Return iterator in which the signs of non-zero elements
of t and the order of the elements are permuted.
Examples
========
>>> from sympy.utilities.iterables import signed_permutations
>>> list(signed_permutations((0, 1, 2)))
[(0, 1, 2), (0, -1, 2), (0, 1, -2), (0, -1, -2), (0, 2, 1),
(0, -2, 1), (0, 2, -1), (0, -2, -1), (1, 0, 2), (-1, 0, 2),
(1, 0, -2), (-1, 0, -2), (1, 2, 0), (-1, 2, 0), (1, -2, 0),
(-1, -2, 0), (2, 0, 1), (-2, 0, 1), (2, 0, -1), (-2, 0, -1),
(2, 1, 0), (-2, 1, 0), (2, -1, 0), (-2, -1, 0)]
"""
return (type(t)(i) for j in permutations(t)
for i in permute_signs(j))
|
8f87d255d2e3b2be32af8efeac81ae7856918356730bd3b39d0a3df58720d186
|
"""
This is our testing framework.
Goals:
* it should be compatible with py.test and operate very similarly
(or identically)
* doesn't require any external dependencies
* preferably all the functionality should be in this file only
* no magic, just import the test file and execute the test functions, that's it
* portable
"""
from __future__ import print_function, division
import os
import sys
import platform
import inspect
import traceback
import pdb
import re
import linecache
import time
from fnmatch import fnmatch
from timeit import default_timer as clock
import doctest as pdoctest # avoid clashing with our doctest() function
from doctest import DocTestFinder, DocTestRunner
import random
import subprocess
import signal
import stat
import tempfile
from sympy.core.cache import clear_cache
from sympy.core.compatibility import exec_, PY3, string_types, range, unwrap
from sympy.utilities.misc import find_executable
from sympy.external import import_module
from sympy.utilities.exceptions import SymPyDeprecationWarning
IS_WINDOWS = (os.name == 'nt')
ON_TRAVIS = os.getenv('TRAVIS_BUILD_NUMBER', None)
# emperically generated list of the proportion of time spent running
# an even split of tests. This should periodically be regenerated.
# A list of [.6, .1, .3] would mean that if the tests are evenly split
# into '1/3', '2/3', '3/3', the first split would take 60% of the time,
# the second 10% and the third 30%. These lists are normalized to sum
# to 1, so [60, 10, 30] has the same behavior as [6, 1, 3] or [.6, .1, .3].
#
# This list can be generated with the code:
# from time import time
# import sympy
#
# delays, num_splits = [], 30
# for i in range(1, num_splits + 1):
# tic = time()
# sympy.test(split='{}/{}'.format(i, num_splits), time_balance=False)
# delays.append(time() - tic)
# tot = sum(delays)
# print([round(x / tot, 4) for x in delays]))
SPLIT_DENSITY = [0.2464, 0.0507, 0.0328, 0.0113, 0.0418, 0.012, 0.0269, 0.0095, 0.091, 0.0215, 0.001, 0.0023, 0.0116, 0.0137, 0.0041, 0.0039, 0.0145, 0.0172, 0.059, 0.0017, 0.0112, 0.0128, 0.0012, 0.0293, 0.0705, 0.0284, 0.1495, 0.0073, 0.0052, 0.0115]
SPLIT_DENSITY_SLOW = [0.3616, 0.0003, 0.0004, 0.0004, 0.0255, 0.0005, 0.0674, 0.0337, 0.1057, 0.0329, 0.0002, 0.0002, 0.0184, 0.0028, 0.0046, 0.0148, 0.0046, 0.0083, 0.0004, 0.0002, 0.0069, 0.0004, 0.0004, 0.0046, 0.0205, 0.1378, 0.1451, 0.0003, 0.0006, 0.0006]
class Skipped(Exception):
pass
class TimeOutError(Exception):
pass
class DependencyError(Exception):
pass
# add more flags ??
future_flags = division.compiler_flag
def _indent(s, indent=4):
"""
Add the given number of space characters to the beginning of
every non-blank line in ``s``, and return the result.
If the string ``s`` is Unicode, it is encoded using the stdout
encoding and the ``backslashreplace`` error handler.
"""
# After a 2to3 run the below code is bogus, so wrap it with a version check
if not PY3:
if isinstance(s, unicode):
s = s.encode(pdoctest._encoding, 'backslashreplace')
# This regexp matches the start of non-blank lines:
return re.sub('(?m)^(?!$)', indent*' ', s)
pdoctest._indent = _indent
# override reporter to maintain windows and python3
def _report_failure(self, out, test, example, got):
"""
Report that the given example failed.
"""
s = self._checker.output_difference(example, got, self.optionflags)
s = s.encode('raw_unicode_escape').decode('utf8', 'ignore')
out(self._failure_header(test, example) + s)
if PY3 and IS_WINDOWS:
DocTestRunner.report_failure = _report_failure
def convert_to_native_paths(lst):
"""
Converts a list of '/' separated paths into a list of
native (os.sep separated) paths and converts to lowercase
if the system is case insensitive.
"""
newlst = []
for i, rv in enumerate(lst):
rv = os.path.join(*rv.split("/"))
# on windows the slash after the colon is dropped
if sys.platform == "win32":
pos = rv.find(':')
if pos != -1:
if rv[pos + 1] != '\\':
rv = rv[:pos + 1] + '\\' + rv[pos + 1:]
newlst.append(os.path.normcase(rv))
return newlst
def get_sympy_dir():
"""
Returns the root sympy directory and set the global value
indicating whether the system is case sensitive or not.
"""
this_file = os.path.abspath(__file__)
sympy_dir = os.path.join(os.path.dirname(this_file), "..", "..")
sympy_dir = os.path.normpath(sympy_dir)
return os.path.normcase(sympy_dir)
def setup_pprint():
from sympy import pprint_use_unicode, init_printing
import sympy.interactive.printing as interactive_printing
# force pprint to be in ascii mode in doctests
use_unicode_prev = pprint_use_unicode(False)
# hook our nice, hash-stable strprinter
init_printing(pretty_print=False)
# Prevent init_printing() in doctests from affecting other doctests
interactive_printing.NO_GLOBAL = True
return use_unicode_prev
def run_in_subprocess_with_hash_randomization(
function, function_args=(),
function_kwargs=None, command=sys.executable,
module='sympy.utilities.runtests', force=False):
"""
Run a function in a Python subprocess with hash randomization enabled.
If hash randomization is not supported by the version of Python given, it
returns False. Otherwise, it returns the exit value of the command. The
function is passed to sys.exit(), so the return value of the function will
be the return value.
The environment variable PYTHONHASHSEED is used to seed Python's hash
randomization. If it is set, this function will return False, because
starting a new subprocess is unnecessary in that case. If it is not set,
one is set at random, and the tests are run. Note that if this
environment variable is set when Python starts, hash randomization is
automatically enabled. To force a subprocess to be created even if
PYTHONHASHSEED is set, pass ``force=True``. This flag will not force a
subprocess in Python versions that do not support hash randomization (see
below), because those versions of Python do not support the ``-R`` flag.
``function`` should be a string name of a function that is importable from
the module ``module``, like "_test". The default for ``module`` is
"sympy.utilities.runtests". ``function_args`` and ``function_kwargs``
should be a repr-able tuple and dict, respectively. The default Python
command is sys.executable, which is the currently running Python command.
This function is necessary because the seed for hash randomization must be
set by the environment variable before Python starts. Hence, in order to
use a predetermined seed for tests, we must start Python in a separate
subprocess.
Hash randomization was added in the minor Python versions 2.6.8, 2.7.3,
3.1.5, and 3.2.3, and is enabled by default in all Python versions after
and including 3.3.0.
Examples
========
>>> from sympy.utilities.runtests import (
... run_in_subprocess_with_hash_randomization)
>>> # run the core tests in verbose mode
>>> run_in_subprocess_with_hash_randomization("_test",
... function_args=("core",),
... function_kwargs={'verbose': True}) # doctest: +SKIP
# Will return 0 if sys.executable supports hash randomization and tests
# pass, 1 if they fail, and False if it does not support hash
# randomization.
"""
# Note, we must return False everywhere, not None, as subprocess.call will
# sometimes return None.
# First check if the Python version supports hash randomization
# If it doesn't have this support, it won't reconize the -R flag
p = subprocess.Popen([command, "-RV"], stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
p.communicate()
if p.returncode != 0:
return False
hash_seed = os.getenv("PYTHONHASHSEED")
if not hash_seed:
os.environ["PYTHONHASHSEED"] = str(random.randrange(2**32))
else:
if not force:
return False
function_kwargs = function_kwargs or {}
# Now run the command
commandstring = ("import sys; from %s import %s;sys.exit(%s(*%s, **%s))" %
(module, function, function, repr(function_args),
repr(function_kwargs)))
try:
p = subprocess.Popen([command, "-R", "-c", commandstring])
p.communicate()
except KeyboardInterrupt:
p.wait()
finally:
# Put the environment variable back, so that it reads correctly for
# the current Python process.
if hash_seed is None:
del os.environ["PYTHONHASHSEED"]
else:
os.environ["PYTHONHASHSEED"] = hash_seed
return p.returncode
def run_all_tests(test_args=(), test_kwargs=None,
doctest_args=(), doctest_kwargs=None,
examples_args=(), examples_kwargs=None):
"""
Run all tests.
Right now, this runs the regular tests (bin/test), the doctests
(bin/doctest), the examples (examples/all.py), and the sage tests (see
sympy/external/tests/test_sage.py).
This is what ``setup.py test`` uses.
You can pass arguments and keyword arguments to the test functions that
support them (for now, test, doctest, and the examples). See the
docstrings of those functions for a description of the available options.
For example, to run the solvers tests with colors turned off:
>>> from sympy.utilities.runtests import run_all_tests
>>> run_all_tests(test_args=("solvers",),
... test_kwargs={"colors:False"}) # doctest: +SKIP
"""
tests_successful = True
test_kwargs = test_kwargs or {}
doctest_kwargs = doctest_kwargs or {}
examples_kwargs = examples_kwargs or {'quiet': True}
try:
# Regular tests
if not test(*test_args, **test_kwargs):
# some regular test fails, so set the tests_successful
# flag to false and continue running the doctests
tests_successful = False
# Doctests
print()
if not doctest(*doctest_args, **doctest_kwargs):
tests_successful = False
# Examples
print()
sys.path.append("examples")
from all import run_examples # examples/all.py
if not run_examples(*examples_args, **examples_kwargs):
tests_successful = False
# Sage tests
if sys.platform != "win32" and not PY3 and os.path.exists("bin/test"):
# run Sage tests; Sage currently doesn't support Windows or Python 3
# Only run Sage tests if 'bin/test' is present (it is missing from
# our release because everything in the 'bin' directory gets
# installed).
dev_null = open(os.devnull, 'w')
if subprocess.call("sage -v", shell=True, stdout=dev_null,
stderr=dev_null) == 0:
if subprocess.call("sage -python bin/test "
"sympy/external/tests/test_sage.py",
shell=True, cwd=os.path.dirname(os.path.dirname(os.path.dirname(__file__)))) != 0:
tests_successful = False
if tests_successful:
return
else:
# Return nonzero exit code
sys.exit(1)
except KeyboardInterrupt:
print()
print("DO *NOT* COMMIT!")
sys.exit(1)
def test(*paths, **kwargs):
"""
Run tests in the specified test_*.py files.
Tests in a particular test_*.py file are run if any of the given strings
in ``paths`` matches a part of the test file's path. If ``paths=[]``,
tests in all test_*.py files are run.
Notes:
- If sort=False, tests are run in random order (not default).
- Paths can be entered in native system format or in unix,
forward-slash format.
- Files that are on the blacklist can be tested by providing
their path; they are only excluded if no paths are given.
**Explanation of test results**
====== ===============================================================
Output Meaning
====== ===============================================================
. passed
F failed
X XPassed (expected to fail but passed)
f XFAILed (expected to fail and indeed failed)
s skipped
w slow
T timeout (e.g., when ``--timeout`` is used)
K KeyboardInterrupt (when running the slow tests with ``--slow``,
you can interrupt one of them without killing the test runner)
====== ===============================================================
Colors have no additional meaning and are used just to facilitate
interpreting the output.
Examples
========
>>> import sympy
Run all tests:
>>> sympy.test() # doctest: +SKIP
Run one file:
>>> sympy.test("sympy/core/tests/test_basic.py") # doctest: +SKIP
>>> sympy.test("_basic") # doctest: +SKIP
Run all tests in sympy/functions/ and some particular file:
>>> sympy.test("sympy/core/tests/test_basic.py",
... "sympy/functions") # doctest: +SKIP
Run all tests in sympy/core and sympy/utilities:
>>> sympy.test("/core", "/util") # doctest: +SKIP
Run specific test from a file:
>>> sympy.test("sympy/core/tests/test_basic.py",
... kw="test_equality") # doctest: +SKIP
Run specific test from any file:
>>> sympy.test(kw="subs") # doctest: +SKIP
Run the tests with verbose mode on:
>>> sympy.test(verbose=True) # doctest: +SKIP
Don't sort the test output:
>>> sympy.test(sort=False) # doctest: +SKIP
Turn on post-mortem pdb:
>>> sympy.test(pdb=True) # doctest: +SKIP
Turn off colors:
>>> sympy.test(colors=False) # doctest: +SKIP
Force colors, even when the output is not to a terminal (this is useful,
e.g., if you are piping to ``less -r`` and you still want colors)
>>> sympy.test(force_colors=False) # doctest: +SKIP
The traceback verboseness can be set to "short" or "no" (default is
"short")
>>> sympy.test(tb='no') # doctest: +SKIP
The ``split`` option can be passed to split the test run into parts. The
split currently only splits the test files, though this may change in the
future. ``split`` should be a string of the form 'a/b', which will run
part ``a`` of ``b``. For instance, to run the first half of the test suite:
>>> sympy.test(split='1/2') # doctest: +SKIP
The ``time_balance`` option can be passed in conjunction with ``split``.
If ``time_balance=True`` (the default for ``sympy.test``), sympy will attempt
to split the tests such that each split takes equal time. This heuristic
for balancing is based on pre-recorded test data.
>>> sympy.test(split='1/2', time_balance=True) # doctest: +SKIP
You can disable running the tests in a separate subprocess using
``subprocess=False``. This is done to support seeding hash randomization,
which is enabled by default in the Python versions where it is supported.
If subprocess=False, hash randomization is enabled/disabled according to
whether it has been enabled or not in the calling Python process.
However, even if it is enabled, the seed cannot be printed unless it is
called from a new Python process.
Hash randomization was added in the minor Python versions 2.6.8, 2.7.3,
3.1.5, and 3.2.3, and is enabled by default in all Python versions after
and including 3.3.0.
If hash randomization is not supported ``subprocess=False`` is used
automatically.
>>> sympy.test(subprocess=False) # doctest: +SKIP
To set the hash randomization seed, set the environment variable
``PYTHONHASHSEED`` before running the tests. This can be done from within
Python using
>>> import os
>>> os.environ['PYTHONHASHSEED'] = '42' # doctest: +SKIP
Or from the command line using
$ PYTHONHASHSEED=42 ./bin/test
If the seed is not set, a random seed will be chosen.
Note that to reproduce the same hash values, you must use both the same seed
as well as the same architecture (32-bit vs. 64-bit).
"""
subprocess = kwargs.pop("subprocess", True)
rerun = kwargs.pop("rerun", 0)
# count up from 0, do not print 0
print_counter = lambda i : (print("rerun %d" % (rerun-i))
if rerun-i else None)
if subprocess:
# loop backwards so last i is 0
for i in range(rerun, -1, -1):
print_counter(i)
ret = run_in_subprocess_with_hash_randomization("_test",
function_args=paths, function_kwargs=kwargs)
if ret is False:
break
val = not bool(ret)
# exit on the first failure or if done
if not val or i == 0:
return val
# rerun even if hash randomization is not supported
for i in range(rerun, -1, -1):
print_counter(i)
val = not bool(_test(*paths, **kwargs))
if not val or i == 0:
return val
def _test(*paths, **kwargs):
"""
Internal function that actually runs the tests.
All keyword arguments from ``test()`` are passed to this function except for
``subprocess``.
Returns 0 if tests passed and 1 if they failed. See the docstring of
``test()`` for more information.
"""
verbose = kwargs.get("verbose", False)
tb = kwargs.get("tb", "short")
kw = kwargs.get("kw", None) or ()
# ensure that kw is a tuple
if isinstance(kw, str):
kw = (kw, )
post_mortem = kwargs.get("pdb", False)
colors = kwargs.get("colors", True)
force_colors = kwargs.get("force_colors", False)
sort = kwargs.get("sort", True)
seed = kwargs.get("seed", None)
if seed is None:
seed = random.randrange(100000000)
timeout = kwargs.get("timeout", False)
fail_on_timeout = kwargs.get("fail_on_timeout", False)
if ON_TRAVIS and timeout is False:
# Travis times out if no activity is seen for 10 minutes.
timeout = 595
fail_on_timeout = True
slow = kwargs.get("slow", False)
enhance_asserts = kwargs.get("enhance_asserts", False)
split = kwargs.get('split', None)
time_balance = kwargs.get('time_balance', True)
blacklist = kwargs.get('blacklist', ['sympy/integrals/rubi/rubi_tests/tests'])
blacklist = convert_to_native_paths(blacklist)
fast_threshold = kwargs.get('fast_threshold', None)
slow_threshold = kwargs.get('slow_threshold', None)
r = PyTestReporter(verbose=verbose, tb=tb, colors=colors,
force_colors=force_colors, split=split)
t = SymPyTests(r, kw, post_mortem, seed,
fast_threshold=fast_threshold,
slow_threshold=slow_threshold)
# Show deprecation warnings
import warnings
warnings.simplefilter("error", SymPyDeprecationWarning)
warnings.filterwarnings('error', '.*', DeprecationWarning, module='sympy.*')
test_files = t.get_test_files('sympy')
not_blacklisted = [f for f in test_files
if not any(b in f for b in blacklist)]
if len(paths) == 0:
matched = not_blacklisted
else:
paths = convert_to_native_paths(paths)
matched = []
for f in not_blacklisted:
basename = os.path.basename(f)
for p in paths:
if p in f or fnmatch(basename, p):
matched.append(f)
break
density = None
if time_balance:
if slow:
density = SPLIT_DENSITY_SLOW
else:
density = SPLIT_DENSITY
if split:
matched = split_list(matched, split, density=density)
t._testfiles.extend(matched)
return int(not t.test(sort=sort, timeout=timeout, slow=slow,
enhance_asserts=enhance_asserts, fail_on_timeout=fail_on_timeout))
def doctest(*paths, **kwargs):
r"""
Runs doctests in all \*.py files in the sympy directory which match
any of the given strings in ``paths`` or all tests if paths=[].
Notes:
- Paths can be entered in native system format or in unix,
forward-slash format.
- Files that are on the blacklist can be tested by providing
their path; they are only excluded if no paths are given.
Examples
========
>>> import sympy
Run all tests:
>>> sympy.doctest() # doctest: +SKIP
Run one file:
>>> sympy.doctest("sympy/core/basic.py") # doctest: +SKIP
>>> sympy.doctest("polynomial.rst") # doctest: +SKIP
Run all tests in sympy/functions/ and some particular file:
>>> sympy.doctest("/functions", "basic.py") # doctest: +SKIP
Run any file having polynomial in its name, doc/src/modules/polynomial.rst,
sympy/functions/special/polynomials.py, and sympy/polys/polynomial.py:
>>> sympy.doctest("polynomial") # doctest: +SKIP
The ``split`` option can be passed to split the test run into parts. The
split currently only splits the test files, though this may change in the
future. ``split`` should be a string of the form 'a/b', which will run
part ``a`` of ``b``. Note that the regular doctests and the Sphinx
doctests are split independently. For instance, to run the first half of
the test suite:
>>> sympy.doctest(split='1/2') # doctest: +SKIP
The ``subprocess`` and ``verbose`` options are the same as with the function
``test()``. See the docstring of that function for more information.
"""
subprocess = kwargs.pop("subprocess", True)
rerun = kwargs.pop("rerun", 0)
# count up from 0, do not print 0
print_counter = lambda i : (print("rerun %d" % (rerun-i))
if rerun-i else None)
if subprocess:
# loop backwards so last i is 0
for i in range(rerun, -1, -1):
print_counter(i)
ret = run_in_subprocess_with_hash_randomization("_doctest",
function_args=paths, function_kwargs=kwargs)
if ret is False:
break
val = not bool(ret)
# exit on the first failure or if done
if not val or i == 0:
return val
# rerun even if hash randomization is not supported
for i in range(rerun, -1, -1):
print_counter(i)
val = not bool(_doctest(*paths, **kwargs))
if not val or i == 0:
return val
def _get_doctest_blacklist():
'''Get the default blacklist for the doctests'''
blacklist = []
blacklist.extend([
"doc/src/modules/plotting.rst", # generates live plots
"doc/src/modules/physics/mechanics/autolev_parser.rst",
"sympy/physics/gaussopt.py", # raises deprecation warning
"sympy/galgebra.py", # raises ImportError
"sympy/this.py", # Prints text to the terminal
"sympy/matrices/densearith.py", # raises deprecation warning
"sympy/matrices/densesolve.py", # raises deprecation warning
"sympy/matrices/densetools.py", # raises deprecation warning
"sympy/physics/unitsystems.py", # raises deprecation warning
"sympy/parsing/autolev/_antlr/autolevlexer.py", # generated code
"sympy/parsing/autolev/_antlr/autolevparser.py", # generated code
"sympy/parsing/autolev/_antlr/autolevlistener.py", # generated code
"sympy/parsing/latex/_antlr/latexlexer.py", # generated code
"sympy/parsing/latex/_antlr/latexparser.py", # generated code
"sympy/integrals/rubi/rubi.py"
])
# autolev parser tests
num = 12
for i in range (1, num+1):
blacklist.append("sympy/parsing/autolev/test-examples/ruletest" + str(i) + ".py")
blacklist.extend(["sympy/parsing/autolev/test-examples/pydy-example-repo/mass_spring_damper.py",
"sympy/parsing/autolev/test-examples/pydy-example-repo/chaos_pendulum.py",
"sympy/parsing/autolev/test-examples/pydy-example-repo/double_pendulum.py",
"sympy/parsing/autolev/test-examples/pydy-example-repo/non_min_pendulum.py"])
if import_module('numpy') is None:
blacklist.extend([
"sympy/plotting/experimental_lambdify.py",
"sympy/plotting/plot_implicit.py",
"examples/advanced/autowrap_integrators.py",
"examples/advanced/autowrap_ufuncify.py",
"examples/intermediate/sample.py",
"examples/intermediate/mplot2d.py",
"examples/intermediate/mplot3d.py",
"doc/src/modules/numeric-computation.rst"
])
else:
if import_module('matplotlib') is None:
blacklist.extend([
"examples/intermediate/mplot2d.py",
"examples/intermediate/mplot3d.py"
])
else:
# Use a non-windowed backend, so that the tests work on Travis
import matplotlib
matplotlib.use('Agg')
if import_module('pyglet') is None:
blacklist.extend(["sympy/plotting/pygletplot"])
if import_module('theano') is None:
blacklist.extend([
"sympy/printing/theanocode.py",
"doc/src/modules/numeric-computation.rst",
])
if import_module('antlr4') is None:
blacklist.extend([
"sympy/parsing/autolev/__init__.py",
"sympy/parsing/latex/_parse_latex_antlr.py",
])
# disabled because of doctest failures in asmeurer's bot
blacklist.extend([
"sympy/utilities/autowrap.py",
"examples/advanced/autowrap_integrators.py",
"examples/advanced/autowrap_ufuncify.py"
])
# blacklist these modules until issue 4840 is resolved
blacklist.extend([
"sympy/conftest.py",
"sympy/utilities/benchmarking.py"
])
blacklist = convert_to_native_paths(blacklist)
return blacklist
def _doctest(*paths, **kwargs):
"""
Internal function that actually runs the doctests.
All keyword arguments from ``doctest()`` are passed to this function
except for ``subprocess``.
Returns 0 if tests passed and 1 if they failed. See the docstrings of
``doctest()`` and ``test()`` for more information.
"""
from sympy import pprint_use_unicode
normal = kwargs.get("normal", False)
verbose = kwargs.get("verbose", False)
colors = kwargs.get("colors", True)
force_colors = kwargs.get("force_colors", False)
blacklist = kwargs.get("blacklist", [])
split = kwargs.get('split', None)
blacklist.extend(_get_doctest_blacklist())
# Use a non-windowed backend, so that the tests work on Travis
if import_module('matplotlib') is not None:
import matplotlib
matplotlib.use('Agg')
# Disable warnings for external modules
import sympy.external
sympy.external.importtools.WARN_OLD_VERSION = False
sympy.external.importtools.WARN_NOT_INSTALLED = False
# Disable showing up of plots
from sympy.plotting.plot import unset_show
unset_show()
# Show deprecation warnings
import warnings
warnings.simplefilter("error", SymPyDeprecationWarning)
warnings.filterwarnings('error', '.*', DeprecationWarning, module='sympy.*')
r = PyTestReporter(verbose, split=split, colors=colors,\
force_colors=force_colors)
t = SymPyDocTests(r, normal)
test_files = t.get_test_files('sympy')
test_files.extend(t.get_test_files('examples', init_only=False))
not_blacklisted = [f for f in test_files
if not any(b in f for b in blacklist)]
if len(paths) == 0:
matched = not_blacklisted
else:
# take only what was requested...but not blacklisted items
# and allow for partial match anywhere or fnmatch of name
paths = convert_to_native_paths(paths)
matched = []
for f in not_blacklisted:
basename = os.path.basename(f)
for p in paths:
if p in f or fnmatch(basename, p):
matched.append(f)
break
if split:
matched = split_list(matched, split)
t._testfiles.extend(matched)
# run the tests and record the result for this *py portion of the tests
if t._testfiles:
failed = not t.test()
else:
failed = False
# N.B.
# --------------------------------------------------------------------
# Here we test *.rst files at or below doc/src. Code from these must
# be self supporting in terms of imports since there is no importing
# of necessary modules by doctest.testfile. If you try to pass *.py
# files through this they might fail because they will lack the needed
# imports and smarter parsing that can be done with source code.
#
test_files = t.get_test_files('doc/src', '*.rst', init_only=False)
test_files.sort()
not_blacklisted = [f for f in test_files
if not any(b in f for b in blacklist)]
if len(paths) == 0:
matched = not_blacklisted
else:
# Take only what was requested as long as it's not on the blacklist.
# Paths were already made native in *py tests so don't repeat here.
# There's no chance of having a *py file slip through since we
# only have *rst files in test_files.
matched = []
for f in not_blacklisted:
basename = os.path.basename(f)
for p in paths:
if p in f or fnmatch(basename, p):
matched.append(f)
break
if split:
matched = split_list(matched, split)
first_report = True
for rst_file in matched:
if not os.path.isfile(rst_file):
continue
old_displayhook = sys.displayhook
try:
use_unicode_prev = setup_pprint()
out = sympytestfile(
rst_file, module_relative=False, encoding='utf-8',
optionflags=pdoctest.ELLIPSIS | pdoctest.NORMALIZE_WHITESPACE |
pdoctest.IGNORE_EXCEPTION_DETAIL)
finally:
# make sure we return to the original displayhook in case some
# doctest has changed that
sys.displayhook = old_displayhook
# The NO_GLOBAL flag overrides the no_global flag to init_printing
# if True
import sympy.interactive.printing as interactive_printing
interactive_printing.NO_GLOBAL = False
pprint_use_unicode(use_unicode_prev)
rstfailed, tested = out
if tested:
failed = rstfailed or failed
if first_report:
first_report = False
msg = 'rst doctests start'
if not t._testfiles:
r.start(msg=msg)
else:
r.write_center(msg)
print()
# use as the id, everything past the first 'sympy'
file_id = rst_file[rst_file.find('sympy') + len('sympy') + 1:]
print(file_id, end=" ")
# get at least the name out so it is know who is being tested
wid = r.terminal_width - len(file_id) - 1 # update width
test_file = '[%s]' % (tested)
report = '[%s]' % (rstfailed or 'OK')
print(''.join(
[test_file, ' '*(wid - len(test_file) - len(report)), report])
)
# the doctests for *py will have printed this message already if there was
# a failure, so now only print it if there was intervening reporting by
# testing the *rst as evidenced by first_report no longer being True.
if not first_report and failed:
print()
print("DO *NOT* COMMIT!")
return int(failed)
sp = re.compile(r'([0-9]+)/([1-9][0-9]*)')
def split_list(l, split, density=None):
"""
Splits a list into part a of b
split should be a string of the form 'a/b'. For instance, '1/3' would give
the split one of three.
If the length of the list is not divisible by the number of splits, the
last split will have more items.
`density` may be specified as a list. If specified,
tests will be balanced so that each split has as equal-as-possible
amount of mass according to `density`.
>>> from sympy.utilities.runtests import split_list
>>> a = list(range(10))
>>> split_list(a, '1/3')
[0, 1, 2]
>>> split_list(a, '2/3')
[3, 4, 5]
>>> split_list(a, '3/3')
[6, 7, 8, 9]
"""
m = sp.match(split)
if not m:
raise ValueError("split must be a string of the form a/b where a and b are ints")
i, t = map(int, m.groups())
if not density:
return l[(i - 1)*len(l)//t : i*len(l)//t]
# normalize density
tot = sum(density)
density = [x / tot for x in density]
def density_inv(x):
"""Interpolate the inverse to the cumulative
distribution function given by density"""
if x <= 0:
return 0
if x >= sum(density):
return 1
# find the first time the cumulative sum surpasses x
# and linearly interpolate
cumm = 0
for i, d in enumerate(density):
cumm += d
if cumm >= x:
break
frac = (d - (cumm - x)) / d
return (i + frac) / len(density)
lower_frac = density_inv((i - 1) / t)
higher_frac = density_inv(i / t)
return l[int(lower_frac*len(l)) : int(higher_frac*len(l))]
from collections import namedtuple
SymPyTestResults = namedtuple('TestResults', 'failed attempted')
def sympytestfile(filename, module_relative=True, name=None, package=None,
globs=None, verbose=None, report=True, optionflags=0,
extraglobs=None, raise_on_error=False,
parser=pdoctest.DocTestParser(), encoding=None):
"""
Test examples in the given file. Return (#failures, #tests).
Optional keyword arg ``module_relative`` specifies how filenames
should be interpreted:
- If ``module_relative`` is True (the default), then ``filename``
specifies a module-relative path. By default, this path is
relative to the calling module's directory; but if the
``package`` argument is specified, then it is relative to that
package. To ensure os-independence, ``filename`` should use
"/" characters to separate path segments, and should not
be an absolute path (i.e., it may not begin with "/").
- If ``module_relative`` is False, then ``filename`` specifies an
os-specific path. The path may be absolute or relative (to
the current working directory).
Optional keyword arg ``name`` gives the name of the test; by default
use the file's basename.
Optional keyword argument ``package`` is a Python package or the
name of a Python package whose directory should be used as the
base directory for a module relative filename. If no package is
specified, then the calling module's directory is used as the base
directory for module relative filenames. It is an error to
specify ``package`` if ``module_relative`` is False.
Optional keyword arg ``globs`` gives a dict to be used as the globals
when executing examples; by default, use {}. A copy of this dict
is actually used for each docstring, so that each docstring's
examples start with a clean slate.
Optional keyword arg ``extraglobs`` gives a dictionary that should be
merged into the globals that are used to execute examples. By
default, no extra globals are used.
Optional keyword arg ``verbose`` prints lots of stuff if true, prints
only failures if false; by default, it's true iff "-v" is in sys.argv.
Optional keyword arg ``report`` prints a summary at the end when true,
else prints nothing at the end. In verbose mode, the summary is
detailed, else very brief (in fact, empty if all tests passed).
Optional keyword arg ``optionflags`` or's together module constants,
and defaults to 0. Possible values (see the docs for details):
- DONT_ACCEPT_TRUE_FOR_1
- DONT_ACCEPT_BLANKLINE
- NORMALIZE_WHITESPACE
- ELLIPSIS
- SKIP
- IGNORE_EXCEPTION_DETAIL
- REPORT_UDIFF
- REPORT_CDIFF
- REPORT_NDIFF
- REPORT_ONLY_FIRST_FAILURE
Optional keyword arg ``raise_on_error`` raises an exception on the
first unexpected exception or failure. This allows failures to be
post-mortem debugged.
Optional keyword arg ``parser`` specifies a DocTestParser (or
subclass) that should be used to extract tests from the files.
Optional keyword arg ``encoding`` specifies an encoding that should
be used to convert the file to unicode.
Advanced tomfoolery: testmod runs methods of a local instance of
class doctest.Tester, then merges the results into (or creates)
global Tester instance doctest.master. Methods of doctest.master
can be called directly too, if you want to do something unusual.
Passing report=0 to testmod is especially useful then, to delay
displaying a summary. Invoke doctest.master.summarize(verbose)
when you're done fiddling.
"""
if package and not module_relative:
raise ValueError("Package may only be specified for module-"
"relative paths.")
# Relativize the path
if not PY3:
text, filename = pdoctest._load_testfile(
filename, package, module_relative)
if encoding is not None:
text = text.decode(encoding)
else:
text, filename = pdoctest._load_testfile(
filename, package, module_relative, encoding)
# If no name was given, then use the file's name.
if name is None:
name = os.path.basename(filename)
# Assemble the globals.
if globs is None:
globs = {}
else:
globs = globs.copy()
if extraglobs is not None:
globs.update(extraglobs)
if '__name__' not in globs:
globs['__name__'] = '__main__'
if raise_on_error:
runner = pdoctest.DebugRunner(verbose=verbose, optionflags=optionflags)
else:
runner = SymPyDocTestRunner(verbose=verbose, optionflags=optionflags)
runner._checker = SymPyOutputChecker()
# Read the file, convert it to a test, and run it.
test = parser.get_doctest(text, globs, name, filename, 0)
runner.run(test, compileflags=future_flags)
if report:
runner.summarize()
if pdoctest.master is None:
pdoctest.master = runner
else:
pdoctest.master.merge(runner)
return SymPyTestResults(runner.failures, runner.tries)
class SymPyTests(object):
def __init__(self, reporter, kw="", post_mortem=False,
seed=None, fast_threshold=None, slow_threshold=None):
self._post_mortem = post_mortem
self._kw = kw
self._count = 0
self._root_dir = sympy_dir
self._reporter = reporter
self._reporter.root_dir(self._root_dir)
self._testfiles = []
self._seed = seed if seed is not None else random.random()
# Defaults in seconds, from human / UX design limits
# http://www.nngroup.com/articles/response-times-3-important-limits/
#
# These defaults are *NOT* set in stone as we are measuring different
# things, so others feel free to come up with a better yardstick :)
if fast_threshold:
self._fast_threshold = float(fast_threshold)
else:
self._fast_threshold = 0.1
if slow_threshold:
self._slow_threshold = float(slow_threshold)
else:
self._slow_threshold = 10
def test(self, sort=False, timeout=False, slow=False,
enhance_asserts=False, fail_on_timeout=False):
"""
Runs the tests returning True if all tests pass, otherwise False.
If sort=False run tests in random order.
"""
if sort:
self._testfiles.sort()
elif slow:
pass
else:
random.seed(self._seed)
random.shuffle(self._testfiles)
self._reporter.start(self._seed)
for f in self._testfiles:
try:
self.test_file(f, sort, timeout, slow,
enhance_asserts, fail_on_timeout)
except KeyboardInterrupt:
print(" interrupted by user")
self._reporter.finish()
raise
return self._reporter.finish()
def _enhance_asserts(self, source):
from ast import (NodeTransformer, Compare, Name, Store, Load, Tuple,
Assign, BinOp, Str, Mod, Assert, parse, fix_missing_locations)
ops = {"Eq": '==', "NotEq": '!=', "Lt": '<', "LtE": '<=',
"Gt": '>', "GtE": '>=', "Is": 'is', "IsNot": 'is not',
"In": 'in', "NotIn": 'not in'}
class Transform(NodeTransformer):
def visit_Assert(self, stmt):
if isinstance(stmt.test, Compare):
compare = stmt.test
values = [compare.left] + compare.comparators
names = [ "_%s" % i for i, _ in enumerate(values) ]
names_store = [ Name(n, Store()) for n in names ]
names_load = [ Name(n, Load()) for n in names ]
target = Tuple(names_store, Store())
value = Tuple(values, Load())
assign = Assign([target], value)
new_compare = Compare(names_load[0], compare.ops, names_load[1:])
msg_format = "\n%s " + "\n%s ".join([ ops[op.__class__.__name__] for op in compare.ops ]) + "\n%s"
msg = BinOp(Str(msg_format), Mod(), Tuple(names_load, Load()))
test = Assert(new_compare, msg, lineno=stmt.lineno, col_offset=stmt.col_offset)
return [assign, test]
else:
return stmt
tree = parse(source)
new_tree = Transform().visit(tree)
return fix_missing_locations(new_tree)
def test_file(self, filename, sort=True, timeout=False, slow=False,
enhance_asserts=False, fail_on_timeout=False):
reporter = self._reporter
funcs = []
try:
gl = {'__file__': filename}
try:
if PY3:
open_file = lambda: open(filename, encoding="utf8")
else:
open_file = lambda: open(filename)
with open_file() as f:
source = f.read()
if self._kw:
for l in source.splitlines():
if l.lstrip().startswith('def '):
if any(l.find(k) != -1 for k in self._kw):
break
else:
return
if enhance_asserts:
try:
source = self._enhance_asserts(source)
except ImportError:
pass
code = compile(source, filename, "exec")
exec_(code, gl)
except (SystemExit, KeyboardInterrupt):
raise
except ImportError:
reporter.import_error(filename, sys.exc_info())
return
except Exception:
reporter.test_exception(sys.exc_info())
clear_cache()
self._count += 1
random.seed(self._seed)
disabled = gl.get("disabled", False)
if not disabled:
# we need to filter only those functions that begin with 'test_'
# We have to be careful about decorated functions. As long as
# the decorator uses functools.wraps, we can detect it.
funcs = []
for f in gl:
if (f.startswith("test_") and (inspect.isfunction(gl[f])
or inspect.ismethod(gl[f]))):
func = gl[f]
# Handle multiple decorators
while hasattr(func, '__wrapped__'):
func = func.__wrapped__
if inspect.getsourcefile(func) == filename:
funcs.append(gl[f])
if slow:
funcs = [f for f in funcs if getattr(f, '_slow', False)]
# Sorting of XFAILed functions isn't fixed yet :-(
funcs.sort(key=lambda x: inspect.getsourcelines(x)[1])
i = 0
while i < len(funcs):
if inspect.isgeneratorfunction(funcs[i]):
# some tests can be generators, that return the actual
# test functions. We unpack it below:
f = funcs.pop(i)
for fg in f():
func = fg[0]
args = fg[1:]
fgw = lambda: func(*args)
funcs.insert(i, fgw)
i += 1
else:
i += 1
# drop functions that are not selected with the keyword expression:
funcs = [x for x in funcs if self.matches(x)]
if not funcs:
return
except Exception:
reporter.entering_filename(filename, len(funcs))
raise
reporter.entering_filename(filename, len(funcs))
if not sort:
random.shuffle(funcs)
for f in funcs:
start = time.time()
reporter.entering_test(f)
try:
if getattr(f, '_slow', False) and not slow:
raise Skipped("Slow")
if timeout:
self._timeout(f, timeout, fail_on_timeout)
else:
random.seed(self._seed)
f()
except KeyboardInterrupt:
if getattr(f, '_slow', False):
reporter.test_skip("KeyboardInterrupt")
else:
raise
except Exception:
if timeout:
signal.alarm(0) # Disable the alarm. It could not be handled before.
t, v, tr = sys.exc_info()
if t is AssertionError:
reporter.test_fail((t, v, tr))
if self._post_mortem:
pdb.post_mortem(tr)
elif t.__name__ == "Skipped":
reporter.test_skip(v)
elif t.__name__ == "XFail":
reporter.test_xfail()
elif t.__name__ == "XPass":
reporter.test_xpass(v)
else:
reporter.test_exception((t, v, tr))
if self._post_mortem:
pdb.post_mortem(tr)
else:
reporter.test_pass()
taken = time.time() - start
if taken > self._slow_threshold:
reporter.slow_test_functions.append((f.__name__, taken))
if getattr(f, '_slow', False) and slow:
if taken < self._fast_threshold:
reporter.fast_test_functions.append((f.__name__, taken))
reporter.leaving_filename()
def _timeout(self, function, timeout, fail_on_timeout):
def callback(x, y):
signal.alarm(0)
if fail_on_timeout:
raise TimeOutError("Timed out after %d seconds" % timeout)
else:
raise Skipped("Timeout")
signal.signal(signal.SIGALRM, callback)
signal.alarm(timeout) # Set an alarm with a given timeout
function()
signal.alarm(0) # Disable the alarm
def matches(self, x):
"""
Does the keyword expression self._kw match "x"? Returns True/False.
Always returns True if self._kw is "".
"""
if not self._kw:
return True
for kw in self._kw:
if x.__name__.find(kw) != -1:
return True
return False
def get_test_files(self, dir, pat='test_*.py'):
"""
Returns the list of test_*.py (default) files at or below directory
``dir`` relative to the sympy home directory.
"""
dir = os.path.join(self._root_dir, convert_to_native_paths([dir])[0])
g = []
for path, folders, files in os.walk(dir):
g.extend([os.path.join(path, f) for f in files if fnmatch(f, pat)])
return sorted([os.path.normcase(gi) for gi in g])
class SymPyDocTests(object):
def __init__(self, reporter, normal):
self._count = 0
self._root_dir = sympy_dir
self._reporter = reporter
self._reporter.root_dir(self._root_dir)
self._normal = normal
self._testfiles = []
def test(self):
"""
Runs the tests and returns True if all tests pass, otherwise False.
"""
self._reporter.start()
for f in self._testfiles:
try:
self.test_file(f)
except KeyboardInterrupt:
print(" interrupted by user")
self._reporter.finish()
raise
return self._reporter.finish()
def test_file(self, filename):
clear_cache()
from sympy.core.compatibility import StringIO
import sympy.interactive.printing as interactive_printing
from sympy import pprint_use_unicode
rel_name = filename[len(self._root_dir) + 1:]
dirname, file = os.path.split(filename)
module = rel_name.replace(os.sep, '.')[:-3]
if rel_name.startswith("examples"):
# Examples files do not have __init__.py files,
# So we have to temporarily extend sys.path to import them
sys.path.insert(0, dirname)
module = file[:-3] # remove ".py"
try:
module = pdoctest._normalize_module(module)
tests = SymPyDocTestFinder().find(module)
except (SystemExit, KeyboardInterrupt):
raise
except ImportError:
self._reporter.import_error(filename, sys.exc_info())
return
finally:
if rel_name.startswith("examples"):
del sys.path[0]
tests = [test for test in tests if len(test.examples) > 0]
# By default tests are sorted by alphabetical order by function name.
# We sort by line number so one can edit the file sequentially from
# bottom to top. However, if there are decorated functions, their line
# numbers will be too large and for now one must just search for these
# by text and function name.
tests.sort(key=lambda x: -x.lineno)
if not tests:
return
self._reporter.entering_filename(filename, len(tests))
for test in tests:
assert len(test.examples) != 0
# check if there are external dependencies which need to be met
if '_doctest_depends_on' in test.globs:
try:
self._check_dependencies(**test.globs['_doctest_depends_on'])
except DependencyError as e:
self._reporter.test_skip(v="\n" + str(e))
continue
if self._reporter._verbose:
self._reporter.write("\n{} ".format(test.name))
runner = SymPyDocTestRunner(optionflags=pdoctest.ELLIPSIS |
pdoctest.NORMALIZE_WHITESPACE |
pdoctest.IGNORE_EXCEPTION_DETAIL)
runner._checker = SymPyOutputChecker()
old = sys.stdout
new = StringIO()
sys.stdout = new
# If the testing is normal, the doctests get importing magic to
# provide the global namespace. If not normal (the default) then
# then must run on their own; all imports must be explicit within
# a function's docstring. Once imported that import will be
# available to the rest of the tests in a given function's
# docstring (unless clear_globs=True below).
if not self._normal:
test.globs = {}
# if this is uncommented then all the test would get is what
# comes by default with a "from sympy import *"
#exec('from sympy import *') in test.globs
test.globs['print_function'] = print_function
old_displayhook = sys.displayhook
use_unicode_prev = setup_pprint()
try:
f, t = runner.run(test, compileflags=future_flags,
out=new.write, clear_globs=False)
except KeyboardInterrupt:
raise
finally:
sys.stdout = old
if f > 0:
self._reporter.doctest_fail(test.name, new.getvalue())
else:
self._reporter.test_pass()
sys.displayhook = old_displayhook
interactive_printing.NO_GLOBAL = False
pprint_use_unicode(use_unicode_prev)
self._reporter.leaving_filename()
def get_test_files(self, dir, pat='*.py', init_only=True):
r"""
Returns the list of \*.py files (default) from which docstrings
will be tested which are at or below directory ``dir``. By default,
only those that have an __init__.py in their parent directory
and do not start with ``test_`` will be included.
"""
def importable(x):
"""
Checks if given pathname x is an importable module by checking for
__init__.py file.
Returns True/False.
Currently we only test if the __init__.py file exists in the
directory with the file "x" (in theory we should also test all the
parent dirs).
"""
init_py = os.path.join(os.path.dirname(x), "__init__.py")
return os.path.exists(init_py)
dir = os.path.join(self._root_dir, convert_to_native_paths([dir])[0])
g = []
for path, folders, files in os.walk(dir):
g.extend([os.path.join(path, f) for f in files
if not f.startswith('test_') and fnmatch(f, pat)])
if init_only:
# skip files that are not importable (i.e. missing __init__.py)
g = [x for x in g if importable(x)]
return [os.path.normcase(gi) for gi in g]
def _check_dependencies(self,
executables=(),
modules=(),
disable_viewers=()):
"""
Checks if the dependencies for the test are installed.
Raises ``DependencyError`` it at least one dependency is not installed.
"""
for executable in executables:
if not find_executable(executable):
raise DependencyError("Could not find %s" % executable)
for module in modules:
if module == 'matplotlib':
matplotlib = import_module(
'matplotlib',
__import__kwargs={'fromlist':
['pyplot', 'cm', 'collections']},
min_module_version='1.0.0', catch=(RuntimeError,))
if matplotlib is None:
raise DependencyError("Could not import matplotlib")
else:
if not import_module(module):
raise DependencyError("Could not import %s" % module)
if disable_viewers:
tempdir = tempfile.mkdtemp()
os.environ['PATH'] = '%s:%s' % (tempdir, os.environ['PATH'])
vw = ('#!/usr/bin/env {}\n'
'import sys\n'
'if len(sys.argv) <= 1:\n'
' exit("wrong number of args")\n').format(
'python3' if PY3 else 'python')
for viewer in disable_viewers:
with open(os.path.join(tempdir, viewer), 'w') as fh:
fh.write(vw)
# make the file executable
os.chmod(os.path.join(tempdir, viewer),
stat.S_IREAD | stat.S_IWRITE | stat.S_IXUSR)
if 'pyglet' in modules:
# monkey-patch pyglet s.t. it does not open a window during
# doctesting
import pyglet
class DummyWindow(object):
def __init__(self, *args, **kwargs):
self.has_exit = True
self.width = 600
self.height = 400
def set_vsync(self, x):
pass
def switch_to(self):
pass
def push_handlers(self, x):
pass
def close(self):
pass
pyglet.window.Window = DummyWindow
class SymPyDocTestFinder(DocTestFinder):
"""
A class used to extract the DocTests that are relevant to a given
object, from its docstring and the docstrings of its contained
objects. Doctests can currently be extracted from the following
object types: modules, functions, classes, methods, staticmethods,
classmethods, and properties.
Modified from doctest's version to look harder for code that
appears comes from a different module. For example, the @vectorize
decorator makes it look like functions come from multidimensional.py
even though their code exists elsewhere.
"""
def _find(self, tests, obj, name, module, source_lines, globs, seen):
"""
Find tests for the given object and any contained objects, and
add them to ``tests``.
"""
if self._verbose:
print('Finding tests in %s' % name)
# If we've already processed this object, then ignore it.
if id(obj) in seen:
return
seen[id(obj)] = 1
# Make sure we don't run doctests for classes outside of sympy, such
# as in numpy or scipy.
if inspect.isclass(obj):
if obj.__module__.split('.')[0] != 'sympy':
return
# Find a test for this object, and add it to the list of tests.
test = self._get_test(obj, name, module, globs, source_lines)
if test is not None:
tests.append(test)
if not self._recurse:
return
# Look for tests in a module's contained objects.
if inspect.ismodule(obj):
for rawname, val in obj.__dict__.items():
# Recurse to functions & classes.
if inspect.isfunction(val) or inspect.isclass(val):
# Make sure we don't run doctests functions or classes
# from different modules
if val.__module__ != module.__name__:
continue
assert self._from_module(module, val), \
"%s is not in module %s (rawname %s)" % (val, module, rawname)
try:
valname = '%s.%s' % (name, rawname)
self._find(tests, val, valname, module,
source_lines, globs, seen)
except KeyboardInterrupt:
raise
# Look for tests in a module's __test__ dictionary.
for valname, val in getattr(obj, '__test__', {}).items():
if not isinstance(valname, string_types):
raise ValueError("SymPyDocTestFinder.find: __test__ keys "
"must be strings: %r" %
(type(valname),))
if not (inspect.isfunction(val) or inspect.isclass(val) or
inspect.ismethod(val) or inspect.ismodule(val) or
isinstance(val, string_types)):
raise ValueError("SymPyDocTestFinder.find: __test__ values "
"must be strings, functions, methods, "
"classes, or modules: %r" %
(type(val),))
valname = '%s.__test__.%s' % (name, valname)
self._find(tests, val, valname, module, source_lines,
globs, seen)
# Look for tests in a class's contained objects.
if inspect.isclass(obj):
for valname, val in obj.__dict__.items():
# Special handling for staticmethod/classmethod.
if isinstance(val, staticmethod):
val = getattr(obj, valname)
if isinstance(val, classmethod):
val = getattr(obj, valname).__func__
# Recurse to methods, properties, and nested classes.
if ((inspect.isfunction(unwrap(val)) or
inspect.isclass(val) or
isinstance(val, property)) and
self._from_module(module, val)):
# Make sure we don't run doctests functions or classes
# from different modules
if isinstance(val, property):
if hasattr(val.fget, '__module__'):
if val.fget.__module__ != module.__name__:
continue
else:
if val.__module__ != module.__name__:
continue
assert self._from_module(module, val), \
"%s is not in module %s (valname %s)" % (
val, module, valname)
valname = '%s.%s' % (name, valname)
self._find(tests, val, valname, module, source_lines,
globs, seen)
def _get_test(self, obj, name, module, globs, source_lines):
"""
Return a DocTest for the given object, if it defines a docstring;
otherwise, return None.
"""
lineno = None
# Extract the object's docstring. If it doesn't have one,
# then return None (no test for this object).
if isinstance(obj, string_types):
# obj is a string in the case for objects in the polys package.
# Note that source_lines is a binary string (compiled polys
# modules), which can't be handled by _find_lineno so determine
# the line number here.
docstring = obj
matches = re.findall(r"line \d+", name)
assert len(matches) == 1, \
"string '%s' does not contain lineno " % name
# NOTE: this is not the exact linenumber but its better than no
# lineno ;)
lineno = int(matches[0][5:])
else:
try:
if obj.__doc__ is None:
docstring = ''
else:
docstring = obj.__doc__
if not isinstance(docstring, string_types):
docstring = str(docstring)
except (TypeError, AttributeError):
docstring = ''
# Don't bother if the docstring is empty.
if self._exclude_empty and not docstring:
return None
# check that properties have a docstring because _find_lineno
# assumes it
if isinstance(obj, property):
if obj.fget.__doc__ is None:
return None
# Find the docstring's location in the file.
if lineno is None:
obj = unwrap(obj)
# handling of properties is not implemented in _find_lineno so do
# it here
if hasattr(obj, 'func_closure') and obj.func_closure is not None:
tobj = obj.func_closure[0].cell_contents
elif isinstance(obj, property):
tobj = obj.fget
else:
tobj = obj
lineno = self._find_lineno(tobj, source_lines)
if lineno is None:
return None
# Return a DocTest for this object.
if module is None:
filename = None
else:
filename = getattr(module, '__file__', module.__name__)
if filename[-4:] in (".pyc", ".pyo"):
filename = filename[:-1]
globs['_doctest_depends_on'] = getattr(obj, '_doctest_depends_on', {})
return self._parser.get_doctest(docstring, globs, name,
filename, lineno)
class SymPyDocTestRunner(DocTestRunner):
"""
A class used to run DocTest test cases, and accumulate statistics.
The ``run`` method is used to process a single DocTest case. It
returns a tuple ``(f, t)``, where ``t`` is the number of test cases
tried, and ``f`` is the number of test cases that failed.
Modified from the doctest version to not reset the sys.displayhook (see
issue 5140).
See the docstring of the original DocTestRunner for more information.
"""
def run(self, test, compileflags=None, out=None, clear_globs=True):
"""
Run the examples in ``test``, and display the results using the
writer function ``out``.
The examples are run in the namespace ``test.globs``. If
``clear_globs`` is true (the default), then this namespace will
be cleared after the test runs, to help with garbage
collection. If you would like to examine the namespace after
the test completes, then use ``clear_globs=False``.
``compileflags`` gives the set of flags that should be used by
the Python compiler when running the examples. If not
specified, then it will default to the set of future-import
flags that apply to ``globs``.
The output of each example is checked using
``SymPyDocTestRunner.check_output``, and the results are
formatted by the ``SymPyDocTestRunner.report_*`` methods.
"""
self.test = test
if compileflags is None:
compileflags = pdoctest._extract_future_flags(test.globs)
save_stdout = sys.stdout
if out is None:
out = save_stdout.write
sys.stdout = self._fakeout
# Patch pdb.set_trace to restore sys.stdout during interactive
# debugging (so it's not still redirected to self._fakeout).
# Note that the interactive output will go to *our*
# save_stdout, even if that's not the real sys.stdout; this
# allows us to write test cases for the set_trace behavior.
save_set_trace = pdb.set_trace
self.debugger = pdoctest._OutputRedirectingPdb(save_stdout)
self.debugger.reset()
pdb.set_trace = self.debugger.set_trace
# Patch linecache.getlines, so we can see the example's source
# when we're inside the debugger.
self.save_linecache_getlines = pdoctest.linecache.getlines
linecache.getlines = self.__patched_linecache_getlines
try:
test.globs['print_function'] = print_function
return self.__run(test, compileflags, out)
finally:
sys.stdout = save_stdout
pdb.set_trace = save_set_trace
linecache.getlines = self.save_linecache_getlines
if clear_globs:
test.globs.clear()
# We have to override the name mangled methods.
SymPyDocTestRunner._SymPyDocTestRunner__patched_linecache_getlines = \
DocTestRunner._DocTestRunner__patched_linecache_getlines
SymPyDocTestRunner._SymPyDocTestRunner__run = DocTestRunner._DocTestRunner__run
SymPyDocTestRunner._SymPyDocTestRunner__record_outcome = \
DocTestRunner._DocTestRunner__record_outcome
class SymPyOutputChecker(pdoctest.OutputChecker):
"""
Compared to the OutputChecker from the stdlib our OutputChecker class
supports numerical comparison of floats occurring in the output of the
doctest examples
"""
def __init__(self):
# NOTE OutputChecker is an old-style class with no __init__ method,
# so we can't call the base class version of __init__ here
got_floats = r'(\d+\.\d*|\.\d+)'
# floats in the 'want' string may contain ellipses
want_floats = got_floats + r'(\.{3})?'
front_sep = r'\s|\+|\-|\*|,'
back_sep = front_sep + r'|j|e'
fbeg = r'^%s(?=%s|$)' % (got_floats, back_sep)
fmidend = r'(?<=%s)%s(?=%s|$)' % (front_sep, got_floats, back_sep)
self.num_got_rgx = re.compile(r'(%s|%s)' %(fbeg, fmidend))
fbeg = r'^%s(?=%s|$)' % (want_floats, back_sep)
fmidend = r'(?<=%s)%s(?=%s|$)' % (front_sep, want_floats, back_sep)
self.num_want_rgx = re.compile(r'(%s|%s)' %(fbeg, fmidend))
def check_output(self, want, got, optionflags):
"""
Return True iff the actual output from an example (`got`)
matches the expected output (`want`). These strings are
always considered to match if they are identical; but
depending on what option flags the test runner is using,
several non-exact match types are also possible. See the
documentation for `TestRunner` for more information about
option flags.
"""
# Handle the common case first, for efficiency:
# if they're string-identical, always return true.
if got == want:
return True
# TODO parse integers as well ?
# Parse floats and compare them. If some of the parsed floats contain
# ellipses, skip the comparison.
matches = self.num_got_rgx.finditer(got)
numbers_got = [match.group(1) for match in matches] # list of strs
matches = self.num_want_rgx.finditer(want)
numbers_want = [match.group(1) for match in matches] # list of strs
if len(numbers_got) != len(numbers_want):
return False
if len(numbers_got) > 0:
nw_ = []
for ng, nw in zip(numbers_got, numbers_want):
if '...' in nw:
nw_.append(ng)
continue
else:
nw_.append(nw)
if abs(float(ng)-float(nw)) > 1e-5:
return False
got = self.num_got_rgx.sub(r'%s', got)
got = got % tuple(nw_)
# <BLANKLINE> can be used as a special sequence to signify a
# blank line, unless the DONT_ACCEPT_BLANKLINE flag is used.
if not (optionflags & pdoctest.DONT_ACCEPT_BLANKLINE):
# Replace <BLANKLINE> in want with a blank line.
want = re.sub(r'(?m)^%s\s*?$' % re.escape(pdoctest.BLANKLINE_MARKER),
'', want)
# If a line in got contains only spaces, then remove the
# spaces.
got = re.sub(r'(?m)^\s*?$', '', got)
if got == want:
return True
# This flag causes doctest to ignore any differences in the
# contents of whitespace strings. Note that this can be used
# in conjunction with the ELLIPSIS flag.
if optionflags & pdoctest.NORMALIZE_WHITESPACE:
got = ' '.join(got.split())
want = ' '.join(want.split())
if got == want:
return True
# The ELLIPSIS flag says to let the sequence "..." in `want`
# match any substring in `got`.
if optionflags & pdoctest.ELLIPSIS:
if pdoctest._ellipsis_match(want, got):
return True
# We didn't find any match; return false.
return False
class Reporter(object):
"""
Parent class for all reporters.
"""
pass
class PyTestReporter(Reporter):
"""
Py.test like reporter. Should produce output identical to py.test.
"""
def __init__(self, verbose=False, tb="short", colors=True,
force_colors=False, split=None):
self._verbose = verbose
self._tb_style = tb
self._colors = colors
self._force_colors = force_colors
self._xfailed = 0
self._xpassed = []
self._failed = []
self._failed_doctest = []
self._passed = 0
self._skipped = 0
self._exceptions = []
self._terminal_width = None
self._default_width = 80
self._split = split
self._active_file = ''
self._active_f = None
# TODO: Should these be protected?
self.slow_test_functions = []
self.fast_test_functions = []
# this tracks the x-position of the cursor (useful for positioning
# things on the screen), without the need for any readline library:
self._write_pos = 0
self._line_wrap = False
def root_dir(self, dir):
self._root_dir = dir
@property
def terminal_width(self):
if self._terminal_width is not None:
return self._terminal_width
def findout_terminal_width():
if sys.platform == "win32":
# Windows support is based on:
#
# http://code.activestate.com/recipes/
# 440694-determine-size-of-console-window-on-windows/
from ctypes import windll, create_string_buffer
h = windll.kernel32.GetStdHandle(-12)
csbi = create_string_buffer(22)
res = windll.kernel32.GetConsoleScreenBufferInfo(h, csbi)
if res:
import struct
(_, _, _, _, _, left, _, right, _, _, _) = \
struct.unpack("hhhhHhhhhhh", csbi.raw)
return right - left
else:
return self._default_width
if hasattr(sys.stdout, 'isatty') and not sys.stdout.isatty():
return self._default_width # leave PIPEs alone
try:
process = subprocess.Popen(['stty', '-a'],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
stdout = process.stdout.read()
if PY3:
stdout = stdout.decode("utf-8")
except (OSError, IOError):
pass
else:
# We support the following output formats from stty:
#
# 1) Linux -> columns 80
# 2) OS X -> 80 columns
# 3) Solaris -> columns = 80
re_linux = r"columns\s+(?P<columns>\d+);"
re_osx = r"(?P<columns>\d+)\s*columns;"
re_solaris = r"columns\s+=\s+(?P<columns>\d+);"
for regex in (re_linux, re_osx, re_solaris):
match = re.search(regex, stdout)
if match is not None:
columns = match.group('columns')
try:
width = int(columns)
except ValueError:
pass
if width != 0:
return width
return self._default_width
width = findout_terminal_width()
self._terminal_width = width
return width
def write(self, text, color="", align="left", width=None,
force_colors=False):
"""
Prints a text on the screen.
It uses sys.stdout.write(), so no readline library is necessary.
Parameters
==========
color : choose from the colors below, "" means default color
align : "left"/"right", "left" is a normal print, "right" is aligned on
the right-hand side of the screen, filled with spaces if
necessary
width : the screen width
"""
color_templates = (
("Black", "0;30"),
("Red", "0;31"),
("Green", "0;32"),
("Brown", "0;33"),
("Blue", "0;34"),
("Purple", "0;35"),
("Cyan", "0;36"),
("LightGray", "0;37"),
("DarkGray", "1;30"),
("LightRed", "1;31"),
("LightGreen", "1;32"),
("Yellow", "1;33"),
("LightBlue", "1;34"),
("LightPurple", "1;35"),
("LightCyan", "1;36"),
("White", "1;37"),
)
colors = {}
for name, value in color_templates:
colors[name] = value
c_normal = '\033[0m'
c_color = '\033[%sm'
if width is None:
width = self.terminal_width
if align == "right":
if self._write_pos + len(text) > width:
# we don't fit on the current line, create a new line
self.write("\n")
self.write(" "*(width - self._write_pos - len(text)))
if not self._force_colors and hasattr(sys.stdout, 'isatty') and not \
sys.stdout.isatty():
# the stdout is not a terminal, this for example happens if the
# output is piped to less, e.g. "bin/test | less". In this case,
# the terminal control sequences would be printed verbatim, so
# don't use any colors.
color = ""
elif sys.platform == "win32":
# Windows consoles don't support ANSI escape sequences
color = ""
elif not self._colors:
color = ""
if self._line_wrap:
if text[0] != "\n":
sys.stdout.write("\n")
# Avoid UnicodeEncodeError when printing out test failures
if PY3 and IS_WINDOWS:
text = text.encode('raw_unicode_escape').decode('utf8', 'ignore')
elif PY3 and not sys.stdout.encoding.lower().startswith('utf'):
text = text.encode(sys.stdout.encoding, 'backslashreplace'
).decode(sys.stdout.encoding)
if color == "":
sys.stdout.write(text)
else:
sys.stdout.write("%s%s%s" %
(c_color % colors[color], text, c_normal))
sys.stdout.flush()
l = text.rfind("\n")
if l == -1:
self._write_pos += len(text)
else:
self._write_pos = len(text) - l - 1
self._line_wrap = self._write_pos >= width
self._write_pos %= width
def write_center(self, text, delim="="):
width = self.terminal_width
if text != "":
text = " %s " % text
idx = (width - len(text)) // 2
t = delim*idx + text + delim*(width - idx - len(text))
self.write(t + "\n")
def write_exception(self, e, val, tb):
# remove the first item, as that is always runtests.py
tb = tb.tb_next
t = traceback.format_exception(e, val, tb)
self.write("".join(t))
def start(self, seed=None, msg="test process starts"):
self.write_center(msg)
executable = sys.executable
v = tuple(sys.version_info)
python_version = "%s.%s.%s-%s-%s" % v
implementation = platform.python_implementation()
if implementation == 'PyPy':
implementation += " %s.%s.%s-%s-%s" % sys.pypy_version_info
self.write("executable: %s (%s) [%s]\n" %
(executable, python_version, implementation))
from .misc import ARCH
self.write("architecture: %s\n" % ARCH)
from sympy.core.cache import USE_CACHE
self.write("cache: %s\n" % USE_CACHE)
from sympy.core.compatibility import GROUND_TYPES, HAS_GMPY
version = ''
if GROUND_TYPES =='gmpy':
if HAS_GMPY == 1:
import gmpy
elif HAS_GMPY == 2:
import gmpy2 as gmpy
version = gmpy.version()
self.write("ground types: %s %s\n" % (GROUND_TYPES, version))
numpy = import_module('numpy')
self.write("numpy: %s\n" % (None if not numpy else numpy.__version__))
if seed is not None:
self.write("random seed: %d\n" % seed)
from .misc import HASH_RANDOMIZATION
self.write("hash randomization: ")
hash_seed = os.getenv("PYTHONHASHSEED") or '0'
if HASH_RANDOMIZATION and (hash_seed == "random" or int(hash_seed)):
self.write("on (PYTHONHASHSEED=%s)\n" % hash_seed)
else:
self.write("off\n")
if self._split:
self.write("split: %s\n" % self._split)
self.write('\n')
self._t_start = clock()
def finish(self):
self._t_end = clock()
self.write("\n")
global text, linelen
text = "tests finished: %d passed, " % self._passed
linelen = len(text)
def add_text(mytext):
global text, linelen
"""Break new text if too long."""
if linelen + len(mytext) > self.terminal_width:
text += '\n'
linelen = 0
text += mytext
linelen += len(mytext)
if len(self._failed) > 0:
add_text("%d failed, " % len(self._failed))
if len(self._failed_doctest) > 0:
add_text("%d failed, " % len(self._failed_doctest))
if self._skipped > 0:
add_text("%d skipped, " % self._skipped)
if self._xfailed > 0:
add_text("%d expected to fail, " % self._xfailed)
if len(self._xpassed) > 0:
add_text("%d expected to fail but passed, " % len(self._xpassed))
if len(self._exceptions) > 0:
add_text("%d exceptions, " % len(self._exceptions))
add_text("in %.2f seconds" % (self._t_end - self._t_start))
if self.slow_test_functions:
self.write_center('slowest tests', '_')
sorted_slow = sorted(self.slow_test_functions, key=lambda r: r[1])
for slow_func_name, taken in sorted_slow:
print('%s - Took %.3f seconds' % (slow_func_name, taken))
if self.fast_test_functions:
self.write_center('unexpectedly fast tests', '_')
sorted_fast = sorted(self.fast_test_functions,
key=lambda r: r[1])
for fast_func_name, taken in sorted_fast:
print('%s - Took %.3f seconds' % (fast_func_name, taken))
if len(self._xpassed) > 0:
self.write_center("xpassed tests", "_")
for e in self._xpassed:
self.write("%s: %s\n" % (e[0], e[1]))
self.write("\n")
if self._tb_style != "no" and len(self._exceptions) > 0:
for e in self._exceptions:
filename, f, (t, val, tb) = e
self.write_center("", "_")
if f is None:
s = "%s" % filename
else:
s = "%s:%s" % (filename, f.__name__)
self.write_center(s, "_")
self.write_exception(t, val, tb)
self.write("\n")
if self._tb_style != "no" and len(self._failed) > 0:
for e in self._failed:
filename, f, (t, val, tb) = e
self.write_center("", "_")
self.write_center("%s:%s" % (filename, f.__name__), "_")
self.write_exception(t, val, tb)
self.write("\n")
if self._tb_style != "no" and len(self._failed_doctest) > 0:
for e in self._failed_doctest:
filename, msg = e
self.write_center("", "_")
self.write_center("%s" % filename, "_")
self.write(msg)
self.write("\n")
self.write_center(text)
ok = len(self._failed) == 0 and len(self._exceptions) == 0 and \
len(self._failed_doctest) == 0
if not ok:
self.write("DO *NOT* COMMIT!\n")
return ok
def entering_filename(self, filename, n):
rel_name = filename[len(self._root_dir) + 1:]
self._active_file = rel_name
self._active_file_error = False
self.write(rel_name)
self.write("[%d] " % n)
def leaving_filename(self):
self.write(" ")
if self._active_file_error:
self.write("[FAIL]", "Red", align="right")
else:
self.write("[OK]", "Green", align="right")
self.write("\n")
if self._verbose:
self.write("\n")
def entering_test(self, f):
self._active_f = f
if self._verbose:
self.write("\n" + f.__name__ + " ")
def test_xfail(self):
self._xfailed += 1
self.write("f", "Green")
def test_xpass(self, v):
message = str(v)
self._xpassed.append((self._active_file, message))
self.write("X", "Green")
def test_fail(self, exc_info):
self._failed.append((self._active_file, self._active_f, exc_info))
self.write("F", "Red")
self._active_file_error = True
def doctest_fail(self, name, error_msg):
# the first line contains "******", remove it:
error_msg = "\n".join(error_msg.split("\n")[1:])
self._failed_doctest.append((name, error_msg))
self.write("F", "Red")
self._active_file_error = True
def test_pass(self, char="."):
self._passed += 1
if self._verbose:
self.write("ok", "Green")
else:
self.write(char, "Green")
def test_skip(self, v=None):
char = "s"
self._skipped += 1
if v is not None:
message = str(v)
if message == "KeyboardInterrupt":
char = "K"
elif message == "Timeout":
char = "T"
elif message == "Slow":
char = "w"
if self._verbose:
if v is not None:
self.write(message + ' ', "Blue")
else:
self.write(" - ", "Blue")
self.write(char, "Blue")
def test_exception(self, exc_info):
self._exceptions.append((self._active_file, self._active_f, exc_info))
if exc_info[0] is TimeOutError:
self.write("T", "Red")
else:
self.write("E", "Red")
self._active_file_error = True
def import_error(self, filename, exc_info):
self._exceptions.append((filename, None, exc_info))
rel_name = filename[len(self._root_dir) + 1:]
self.write(rel_name)
self.write("[?] Failed to import", "Red")
self.write(" ")
self.write("[FAIL]", "Red", align="right")
self.write("\n")
sympy_dir = get_sympy_dir()
|
dbe731e7b399f84ce268573119a0f0ecd416fafa6c3ef3ee125bb9be4f28a04d
|
"""Miscellaneous stuff that doesn't really fit anywhere else."""
from __future__ import print_function, division
import sys
import os
import re as _re
import struct
from textwrap import fill, dedent
from sympy.core.compatibility import get_function_name, range, as_int
class Undecidable(ValueError):
# an error to be raised when a decision cannot be made definitively
# where a definitive answer is needed
pass
def filldedent(s, w=70):
"""
Strips leading and trailing empty lines from a copy of `s`, then dedents,
fills and returns it.
Empty line stripping serves to deal with docstrings like this one that
start with a newline after the initial triple quote, inserting an empty
line at the beginning of the string."""
return '\n' + fill(dedent(str(s)).strip('\n'), width=w)
def rawlines(s):
"""Return a cut-and-pastable string that, when printed, is equivalent
to the input. The string returned is formatted so it can be indented
nicely within tests; in some cases it is wrapped in the dedent
function which has to be imported from textwrap.
Examples
========
Note: because there are characters in the examples below that need
to be escaped because they are themselves within a triple quoted
docstring, expressions below look more complicated than they would
be if they were printed in an interpreter window.
>>> from sympy.utilities.misc import rawlines
>>> from sympy import TableForm
>>> s = str(TableForm([[1, 10]], headings=(None, ['a', 'bee'])))
>>> print(rawlines(s))
(
'a bee\\n'
'-----\\n'
'1 10 '
)
>>> print(rawlines('''this
... that'''))
dedent('''\\
this
that''')
>>> print(rawlines('''this
... that
... '''))
dedent('''\\
this
that
''')
>>> s = \"\"\"this
... is a triple '''
... \"\"\"
>>> print(rawlines(s))
dedent(\"\"\"\\
this
is a triple '''
\"\"\")
>>> print(rawlines('''this
... that
... '''))
(
'this\\n'
'that\\n'
' '
)
"""
lines = s.split('\n')
if len(lines) == 1:
return repr(lines[0])
triple = ["'''" in s, '"""' in s]
if any(li.endswith(' ') for li in lines) or '\\' in s or all(triple):
rv = ["("]
# add on the newlines
trailing = s.endswith('\n')
last = len(lines) - 1
for i, li in enumerate(lines):
if i != last or trailing:
rv.append(repr(li)[:-1] + '\\n\'')
else:
rv.append(repr(li))
return '\n '.join(rv) + '\n)'
else:
rv = '\n '.join(lines)
if triple[0]:
return 'dedent("""\\\n %s""")' % rv
else:
return "dedent('''\\\n %s''')" % rv
ARCH = str(struct.calcsize('P') * 8) + "-bit"
# XXX: PyPy doesn't support hash randomization
HASH_RANDOMIZATION = getattr(sys.flags, 'hash_randomization', False)
_debug_tmp = []
_debug_iter = 0
def debug_decorator(func):
"""If SYMPY_DEBUG is True, it will print a nice execution tree with
arguments and results of all decorated functions, else do nothing.
"""
from sympy import SYMPY_DEBUG
if not SYMPY_DEBUG:
return func
def maketree(f, *args, **kw):
global _debug_tmp
global _debug_iter
oldtmp = _debug_tmp
_debug_tmp = []
_debug_iter += 1
def tree(subtrees):
def indent(s, type=1):
x = s.split("\n")
r = "+-%s\n" % x[0]
for a in x[1:]:
if a == "":
continue
if type == 1:
r += "| %s\n" % a
else:
r += " %s\n" % a
return r
if len(subtrees) == 0:
return ""
f = []
for a in subtrees[:-1]:
f.append(indent(a))
f.append(indent(subtrees[-1], 2))
return ''.join(f)
# If there is a bug and the algorithm enters an infinite loop, enable the
# following lines. It will print the names and parameters of all major functions
# that are called, *before* they are called
#from sympy.core.compatibility import reduce
#print("%s%s %s%s" % (_debug_iter, reduce(lambda x, y: x + y, \
# map(lambda x: '-', range(1, 2 + _debug_iter))), get_function_name(f), args))
r = f(*args, **kw)
_debug_iter -= 1
s = "%s%s = %s\n" % (get_function_name(f), args, r)
if _debug_tmp != []:
s += tree(_debug_tmp)
_debug_tmp = oldtmp
_debug_tmp.append(s)
if _debug_iter == 0:
print((_debug_tmp[0]))
_debug_tmp = []
return r
def decorated(*args, **kwargs):
return maketree(func, *args, **kwargs)
return decorated
def debug(*args):
"""
Print ``*args`` if SYMPY_DEBUG is True, else do nothing.
"""
from sympy import SYMPY_DEBUG
if SYMPY_DEBUG:
print(*args, file=sys.stderr)
def find_executable(executable, path=None):
"""Try to find 'executable' in the directories listed in 'path' (a
string listing directories separated by 'os.pathsep'; defaults to
os.environ['PATH']). Returns the complete filename or None if not
found
"""
if path is None:
path = os.environ['PATH']
paths = path.split(os.pathsep)
extlist = ['']
if os.name == 'os2':
(base, ext) = os.path.splitext(executable)
# executable files on OS/2 can have an arbitrary extension, but
# .exe is automatically appended if no dot is present in the name
if not ext:
executable = executable + ".exe"
elif sys.platform == 'win32':
pathext = os.environ['PATHEXT'].lower().split(os.pathsep)
(base, ext) = os.path.splitext(executable)
if ext.lower() not in pathext:
extlist = pathext
for ext in extlist:
execname = executable + ext
if os.path.isfile(execname):
return execname
else:
for p in paths:
f = os.path.join(p, execname)
if os.path.isfile(f):
return f
else:
return None
def func_name(x, short=False):
'''Return function name of `x` (if defined) else the `type(x)`.
If short is True and there is a shorter alias for the result,
return the alias.
Examples
========
>>> from sympy.utilities.misc import func_name
>>> from sympy.abc import x
>>> func_name(x < 1)
'StrictLessThan'
>>> func_name(x < 1, short=True)
'Lt'
See Also
========
sympy.core.compatibility get_function_name
'''
alias = {
'GreaterThan': 'Ge',
'StrictGreaterThan': 'Gt',
'LessThan': 'Le',
'StrictLessThan': 'Lt',
'Equality': 'Eq',
'Unequality': 'Ne',
}
typ = type(x)
if str(typ).startswith("<type '"):
typ = str(typ).split("'")[1].split("'")[0]
elif str(typ).startswith("<class '"):
typ = str(typ).split("'")[1].split("'")[0]
rv = getattr(getattr(x, 'func', x), '__name__', typ)
if short:
rv = alias.get(rv, rv)
return rv
def _replace(reps):
"""Return a function that can make the replacements, given in
``reps``, on a string. The replacements should be given as mapping.
Examples
========
>>> from sympy.utilities.misc import _replace
>>> f = _replace(dict(foo='bar', d='t'))
>>> f('food')
'bart'
>>> f = _replace({})
>>> f('food')
'food'
"""
if not reps:
return lambda x: x
D = lambda match: reps[match.group(0)]
pattern = _re.compile("|".join(
[_re.escape(k) for k, v in reps.items()]), _re.M)
return lambda string: pattern.sub(D, string)
def replace(string, *reps):
"""Return ``string`` with all keys in ``reps`` replaced with
their corresponding values, longer strings first, irrespective
of the order they are given. ``reps`` may be passed as tuples
or a single mapping.
Examples
========
>>> from sympy.utilities.misc import replace
>>> replace('foo', {'oo': 'ar', 'f': 'b'})
'bar'
>>> replace("spamham sha", ("spam", "eggs"), ("sha","md5"))
'eggsham md5'
There is no guarantee that a unique answer will be
obtained if keys in a mapping overlap (i.e. are the same
length and have some identical sequence at the
beginning/end):
>>> reps = [
... ('ab', 'x'),
... ('bc', 'y')]
>>> replace('abc', *reps) in ('xc', 'ay')
True
References
==========
.. [1] https://stackoverflow.com/questions/6116978/python-replace-multiple-strings
"""
if len(reps) == 1:
kv = reps[0]
if type(kv) is dict:
reps = kv
else:
return string.replace(*kv)
else:
reps = dict(reps)
return _replace(reps)(string)
def translate(s, a, b=None, c=None):
"""Return ``s`` where characters have been replaced or deleted.
SYNTAX
======
translate(s, None, deletechars):
all characters in ``deletechars`` are deleted
translate(s, map [,deletechars]):
all characters in ``deletechars`` (if provided) are deleted
then the replacements defined by map are made; if the keys
of map are strings then the longer ones are handled first.
Multicharacter deletions should have a value of ''.
translate(s, oldchars, newchars, deletechars)
all characters in ``deletechars`` are deleted
then each character in ``oldchars`` is replaced with the
corresponding character in ``newchars``
Examples
========
>>> from sympy.utilities.misc import translate
>>> from sympy.core.compatibility import unichr
>>> abc = 'abc'
>>> translate(abc, None, 'a')
'bc'
>>> translate(abc, {'a': 'x'}, 'c')
'xb'
>>> translate(abc, {'abc': 'x', 'a': 'y'})
'x'
>>> translate('abcd', 'ac', 'AC', 'd')
'AbC'
There is no guarantee that a unique answer will be
obtained if keys in a mapping overlap are the same
length and have some identical sequences at the
beginning/end:
>>> translate(abc, {'ab': 'x', 'bc': 'y'}) in ('xc', 'ay')
True
"""
from sympy.core.compatibility import maketrans, PY3
mr = {}
if a is None:
assert c is None
if not b:
return s
c = b
a = b = ''
else:
if type(a) is dict:
short = {}
for k in list(a.keys()):
if (len(k) == 1 and len(a[k]) == 1):
short[k] = a.pop(k)
mr = a
c = b
if short:
a, b = [''.join(i) for i in list(zip(*short.items()))]
else:
a = b = ''
else:
assert len(a) == len(b)
if PY3:
if c:
s = s.translate(maketrans('', '', c))
s = replace(s, mr)
return s.translate(maketrans(a, b))
else:
# when support for Python 2 is dropped, this if-else-block
# can be replaced with the if-clause
if c:
c = list(c)
rem = {}
for i in range(-1, -1 - len(c), -1):
if ord(c[i]) > 255:
rem[c[i]] = ''
c.pop(i)
s = s.translate(None, ''.join(c))
s = replace(s, rem)
if a:
a = list(a)
b = list(b)
for i in range(-1, -1 - len(a), -1):
if ord(a[i]) > 255 or ord(b[i]) > 255:
mr[a.pop(i)] = b.pop(i)
a = ''.join(a)
b = ''.join(b)
s = replace(s, mr)
table = maketrans(a, b)
# s may have become unicode which uses the py3 syntax for translate
if type(table) is str and type(s) is str:
s = s.translate(table)
else:
s = s.translate(dict(
[(i, ord(c)) for i, c in enumerate(table)]))
return s
def ordinal(num):
"""Return ordinal number string of num, e.g. 1 becomes 1st.
"""
# modified from https://codereview.stackexchange.com/questions/41298/producing-ordinal-numbers
n = as_int(num)
k = abs(n) % 100
if 11 <= k <= 13:
suffix = 'th'
elif k % 10 == 1:
suffix = 'st'
elif k % 10 == 2:
suffix = 'nd'
elif k % 10 == 3:
suffix = 'rd'
else:
suffix = 'th'
return str(n) + suffix
|
4e7ccd21bab42d965d5dc5e2be55890d65310997f9502c6504ed5a8f594c773d
|
"""
This module adds context manager for temporary files generated by the tests.
"""
from __future__ import print_function, division
import shutil
class TmpFileManager:
"""
A class to track record of every temporary files created by the tests.
"""
tmp_files = set('')
tmp_folders = set('')
@classmethod
def tmp_file(cls, name=''):
cls.tmp_files.add(name)
return name
@classmethod
def tmp_folder(cls, name=''):
cls.tmp_folders.add(name)
return name
@classmethod
def cleanup(cls):
while cls.tmp_files:
file = cls.tmp_files.pop()
if os.path.isfile(file):
os.remove(file)
while cls.tmp_folders:
folder = cls.tmp_folders.pop()
shutil.rmtree(folder)
def cleanup_tmp_files(test_func):
"""
A decorator to help test codes remove temporary files after the tests.
"""
def wrapper_function():
try:
test_func()
finally:
TmpFileManager.cleanup()
return wrapper_function
|
ba6de918f69943f51e24e7e1e64f3e7767a68500faf2edf5e28af925259b7b56
|
"""
Python code printers
This module contains python code printers for plain python as well as NumPy & SciPy enabled code.
"""
from collections import defaultdict
from functools import wraps
from itertools import chain
from sympy.core import sympify, S
from .precedence import precedence
from .codeprinter import CodePrinter
_kw_py2and3 = {
'and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif',
'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in',
'is', 'lambda', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while',
'with', 'yield', 'None' # 'None' is actually not in Python 2's keyword.kwlist
}
_kw_only_py2 = {'exec', 'print'}
_kw_only_py3 = {'False', 'nonlocal', 'True'}
_known_functions = {
'Abs': 'abs',
}
_known_functions_math = {
'acos': 'acos',
'acosh': 'acosh',
'asin': 'asin',
'asinh': 'asinh',
'atan': 'atan',
'atan2': 'atan2',
'atanh': 'atanh',
'ceiling': 'ceil',
'cos': 'cos',
'cosh': 'cosh',
'erf': 'erf',
'erfc': 'erfc',
'exp': 'exp',
'expm1': 'expm1',
'factorial': 'factorial',
'floor': 'floor',
'gamma': 'gamma',
'hypot': 'hypot',
'loggamma': 'lgamma',
'log': 'log',
'ln': 'log',
'log10': 'log10',
'log1p': 'log1p',
'log2': 'log2',
'sin': 'sin',
'sinh': 'sinh',
'Sqrt': 'sqrt',
'tan': 'tan',
'tanh': 'tanh'
} # Not used from ``math``: [copysign isclose isfinite isinf isnan ldexp frexp pow modf
# radians trunc fmod fsum gcd degrees fabs]
_known_constants_math = {
'Exp1': 'e',
'Pi': 'pi',
'E': 'e'
# Only in python >= 3.5:
# 'Infinity': 'inf',
# 'NaN': 'nan'
}
def _print_known_func(self, expr):
known = self.known_functions[expr.__class__.__name__]
return '{name}({args})'.format(name=self._module_format(known),
args=', '.join(map(lambda arg: self._print(arg), expr.args)))
def _print_known_const(self, expr):
known = self.known_constants[expr.__class__.__name__]
return self._module_format(known)
class AbstractPythonCodePrinter(CodePrinter):
printmethod = "_pythoncode"
language = "Python"
standard = "python3"
reserved_words = _kw_py2and3.union(_kw_only_py3)
modules = None # initialized to a set in __init__
tab = ' '
_kf = dict(chain(
_known_functions.items(),
[(k, 'math.' + v) for k, v in _known_functions_math.items()]
))
_kc = {k: 'math.'+v for k, v in _known_constants_math.items()}
_operators = {'and': 'and', 'or': 'or', 'not': 'not'}
_default_settings = dict(
CodePrinter._default_settings,
user_functions={},
precision=17,
inline=True,
fully_qualified_modules=True,
contract=False
)
def __init__(self, settings=None):
super(AbstractPythonCodePrinter, self).__init__(settings)
self.module_imports = defaultdict(set)
self.known_functions = dict(self._kf, **(settings or {}).get(
'user_functions', {}))
self.known_constants = dict(self._kc, **(settings or {}).get(
'user_constants', {}))
def _get_statement(self, codestring):
return codestring
def _declare_number_const(self, name, value):
return "%s = %s" % (name, value)
def _module_format(self, fqn, register=True):
parts = fqn.split('.')
if register and len(parts) > 1:
self.module_imports['.'.join(parts[:-1])].add(parts[-1])
if self._settings['fully_qualified_modules']:
return fqn
else:
return fqn.split('(')[0].split('[')[0].split('.')[-1]
def _format_code(self, lines):
return lines
def _get_statement(self, codestring):
return "%s" % codestring
def _get_comment(self, text):
return " # {0}".format(text)
def _expand_fold_binary_op(self, op, args):
"""
This method expands a fold on binary operations.
``functools.reduce`` is an example of a folded operation.
For example, the expression
`A + B + C + D`
is folded into
`((A + B) + C) + D`
"""
if len(args) == 1:
return self._print(args[0])
else:
return "%s(%s, %s)" % (
self._module_format(op),
self._expand_fold_binary_op(op, args[:-1]),
self._print(args[-1]),
)
def _expand_reduce_binary_op(self, op, args):
"""
This method expands a reductin on binary operations.
Notice: this is NOT the same as ``functools.reduce``.
For example, the expression
`A + B + C + D`
is reduced into:
`(A + B) + (C + D)`
"""
if len(args) == 1:
return self._print(args[0])
else:
N = len(args)
Nhalf = N // 2
return "%s(%s, %s)" % (
self._module_format(op),
self._expand_reduce_binary_op(args[:Nhalf]),
self._expand_reduce_binary_op(args[Nhalf:]),
)
def _get_einsum_string(self, subranks, contraction_indices):
letters = self._get_letter_generator_for_einsum()
contraction_string = ""
counter = 0
d = {j: min(i) for i in contraction_indices for j in i}
indices = []
for rank_arg in subranks:
lindices = []
for i in range(rank_arg):
if counter in d:
lindices.append(d[counter])
else:
lindices.append(counter)
counter += 1
indices.append(lindices)
mapping = {}
letters_free = []
letters_dum = []
for i in indices:
for j in i:
if j not in mapping:
l = next(letters)
mapping[j] = l
else:
l = mapping[j]
contraction_string += l
if j in d:
if l not in letters_dum:
letters_dum.append(l)
else:
letters_free.append(l)
contraction_string += ","
contraction_string = contraction_string[:-1]
return contraction_string, letters_free, letters_dum
def _print_NaN(self, expr):
return "float('nan')"
def _print_Infinity(self, expr):
return "float('inf')"
def _print_NegativeInfinity(self, expr):
return "float('-inf')"
def _print_ComplexInfinity(self, expr):
return self._print_NaN(expr)
def _print_Mod(self, expr):
PREC = precedence(expr)
return ('{0} % {1}'.format(*map(lambda x: self.parenthesize(x, PREC), expr.args)))
def _print_Piecewise(self, expr):
result = []
i = 0
for arg in expr.args:
e = arg.expr
c = arg.cond
if i == 0:
result.append('(')
result.append('(')
result.append(self._print(e))
result.append(')')
result.append(' if ')
result.append(self._print(c))
result.append(' else ')
i += 1
result = result[:-1]
if result[-1] == 'True':
result = result[:-2]
result.append(')')
else:
result.append(' else None)')
return ''.join(result)
def _print_Relational(self, expr):
"Relational printer for Equality and Unequality"
op = {
'==' :'equal',
'!=' :'not_equal',
'<' :'less',
'<=' :'less_equal',
'>' :'greater',
'>=' :'greater_equal',
}
if expr.rel_op in op:
lhs = self._print(expr.lhs)
rhs = self._print(expr.rhs)
return '({lhs} {op} {rhs})'.format(op=expr.rel_op, lhs=lhs, rhs=rhs)
return super(AbstractPythonCodePrinter, self)._print_Relational(expr)
def _print_ITE(self, expr):
from sympy.functions.elementary.piecewise import Piecewise
return self._print(expr.rewrite(Piecewise))
def _print_Sum(self, expr):
loops = (
'for {i} in range({a}, {b}+1)'.format(
i=self._print(i),
a=self._print(a),
b=self._print(b))
for i, a, b in expr.limits)
return '(builtins.sum({function} {loops}))'.format(
function=self._print(expr.function),
loops=' '.join(loops))
def _print_ImaginaryUnit(self, expr):
return '1j'
def _print_MatrixBase(self, expr):
name = expr.__class__.__name__
func = self.known_functions.get(name, name)
return "%s(%s)" % (func, self._print(expr.tolist()))
_print_SparseMatrix = \
_print_MutableSparseMatrix = \
_print_ImmutableSparseMatrix = \
_print_Matrix = \
_print_DenseMatrix = \
_print_MutableDenseMatrix = \
_print_ImmutableMatrix = \
_print_ImmutableDenseMatrix = \
lambda self, expr: self._print_MatrixBase(expr)
def _indent_codestring(self, codestring):
return '\n'.join([self.tab + line for line in codestring.split('\n')])
def _print_FunctionDefinition(self, fd):
body = '\n'.join(map(lambda arg: self._print(arg), fd.body))
return "def {name}({parameters}):\n{body}".format(
name=self._print(fd.name),
parameters=', '.join([self._print(var.symbol) for var in fd.parameters]),
body=self._indent_codestring(body)
)
def _print_While(self, whl):
body = '\n'.join(map(lambda arg: self._print(arg), whl.body))
return "while {cond}:\n{body}".format(
cond=self._print(whl.condition),
body=self._indent_codestring(body)
)
def _print_Declaration(self, decl):
return '%s = %s' % (
self._print(decl.variable.symbol),
self._print(decl.variable.value)
)
def _print_Return(self, ret):
arg, = ret.args
return 'return %s' % self._print(arg)
def _print_Print(self, prnt):
print_args = ', '.join(map(lambda arg: self._print(arg), prnt.print_args))
if prnt.format_string != None:
print_args = '{0} % ({1})'.format(
self._print(prnt.format_string), print_args)
if prnt.file != None:
print_args += ', file=%s' % self._print(prnt.file)
return 'print(%s)' % print_args
def _print_Stream(self, strm):
if str(strm.name) == 'stdout':
return self._module_format('sys.stdout')
elif str(strm.name) == 'stderr':
return self._module_format('sys.stderr')
else:
return self._print(strm.name)
def _print_NoneToken(self, arg):
return 'None'
class PythonCodePrinter(AbstractPythonCodePrinter):
def _print_sign(self, e):
return '(0.0 if {e} == 0 else {f}(1, {e}))'.format(
f=self._module_format('math.copysign'), e=self._print(e.args[0]))
def _print_Not(self, expr):
PREC = precedence(expr)
return self._operators['not'] + self.parenthesize(expr.args[0], PREC)
for k in PythonCodePrinter._kf:
setattr(PythonCodePrinter, '_print_%s' % k, _print_known_func)
for k in _known_constants_math:
setattr(PythonCodePrinter, '_print_%s' % k, _print_known_const)
def pycode(expr, **settings):
""" Converts an expr to a string of Python code
Parameters
==========
expr : Expr
A SymPy expression.
fully_qualified_modules : bool
Whether or not to write out full module names of functions
(``math.sin`` vs. ``sin``). default: ``True``.
Examples
========
>>> from sympy import tan, Symbol
>>> from sympy.printing.pycode import pycode
>>> pycode(tan(Symbol('x')) + 1)
'math.tan(x) + 1'
"""
return PythonCodePrinter(settings).doprint(expr)
_not_in_mpmath = 'log1p log2'.split()
_in_mpmath = [(k, v) for k, v in _known_functions_math.items() if k not in _not_in_mpmath]
_known_functions_mpmath = dict(_in_mpmath, **{
'sign': 'sign',
})
_known_constants_mpmath = {
'Pi': 'pi'
}
class MpmathPrinter(PythonCodePrinter):
"""
Lambda printer for mpmath which maintains precision for floats
"""
printmethod = "_mpmathcode"
_kf = dict(chain(
_known_functions.items(),
[(k, 'mpmath.' + v) for k, v in _known_functions_mpmath.items()]
))
def _print_Float(self, e):
# XXX: This does not handle setting mpmath.mp.dps. It is assumed that
# the caller of the lambdified function will have set it to sufficient
# precision to match the Floats in the expression.
# Remove 'mpz' if gmpy is installed.
args = str(tuple(map(int, e._mpf_)))
return '{func}({args})'.format(func=self._module_format('mpmath.mpf'), args=args)
def _print_Rational(self, e):
return '{0}({1})/{0}({2})'.format(
self._module_format('mpmath.mpf'),
e.p,
e.q,
)
def _print_uppergamma(self, e):
return "{0}({1}, {2}, {3})".format(
self._module_format('mpmath.gammainc'),
self._print(e.args[0]),
self._print(e.args[1]),
self._module_format('mpmath.inf'))
def _print_lowergamma(self, e):
return "{0}({1}, 0, {2})".format(
self._module_format('mpmath.gammainc'),
self._print(e.args[0]),
self._print(e.args[1]))
def _print_log2(self, e):
return '{0}({1})/{0}(2)'.format(
self._module_format('mpmath.log'), self._print(e.args[0]))
def _print_log1p(self, e):
return '{0}({1}+1)'.format(
self._module_format('mpmath.log'), self._print(e.args[0]))
for k in MpmathPrinter._kf:
setattr(MpmathPrinter, '_print_%s' % k, _print_known_func)
for k in _known_constants_mpmath:
setattr(MpmathPrinter, '_print_%s' % k, _print_known_const)
_not_in_numpy = 'erf erfc factorial gamma loggamma'.split()
_in_numpy = [(k, v) for k, v in _known_functions_math.items() if k not in _not_in_numpy]
_known_functions_numpy = dict(_in_numpy, **{
'acos': 'arccos',
'acosh': 'arccosh',
'asin': 'arcsin',
'asinh': 'arcsinh',
'atan': 'arctan',
'atan2': 'arctan2',
'atanh': 'arctanh',
'exp2': 'exp2',
'sign': 'sign',
})
class NumPyPrinter(PythonCodePrinter):
"""
Numpy printer which handles vectorized piecewise functions,
logical operators, etc.
"""
printmethod = "_numpycode"
_kf = dict(chain(
PythonCodePrinter._kf.items(),
[(k, 'numpy.' + v) for k, v in _known_functions_numpy.items()]
))
_kc = {k: 'numpy.'+v for k, v in _known_constants_math.items()}
def _print_seq(self, seq):
"General sequence printer: converts to tuple"
# Print tuples here instead of lists because numba supports
# tuples in nopython mode.
delimite.get('delimiter', ', ')
return '({},)'.format(delimiter.join(self._print(item) for item in seq))
def _print_MatMul(self, expr):
"Matrix multiplication printer"
return '({0})'.format(').dot('.join(self._print(i) for i in expr.args))
def _print_MatPow(self, expr):
"Matrix power printer"
return '{0}({1}, {2})'.format(self._module_format('numpy.linalg.matrix_power'),
self._print(expr.args[0]), self._print(expr.args[1]))
def _print_Inverse(self, expr):
"Matrix inverse printer"
return '{0}({1})'.format(self._module_format('numpy.linalg.inv'),
self._print(expr.args[0]))
def _print_DotProduct(self, expr):
# DotProduct allows any shape order, but numpy.dot does matrix
# multiplication, so we have to make sure it gets 1 x n by n x 1.
arg1, arg2 = expr.args
if arg1.shape[0] != 1:
arg1 = arg1.T
if arg2.shape[1] != 1:
arg2 = arg2.T
return "%s(%s, %s)" % (self._module_format('numpy.dot'),
self._print(arg1),
self._print(arg2))
def _print_Piecewise(self, expr):
"Piecewise function printer"
exprs = '[{0}]'.format(','.join(self._print(arg.expr) for arg in expr.args))
conds = '[{0}]'.format(','.join(self._print(arg.cond) for arg in expr.args))
# If [default_value, True] is a (expr, cond) sequence in a Piecewise object
# it will behave the same as passing the 'default' kwarg to select()
# *as long as* it is the last element in expr.args.
# If this is not the case, it may be triggered prematurely.
return '{0}({1}, {2}, default=numpy.nan)'.format(self._module_format('numpy.select'), conds, exprs)
def _print_Relational(self, expr):
"Relational printer for Equality and Unequality"
op = {
'==' :'equal',
'!=' :'not_equal',
'<' :'less',
'<=' :'less_equal',
'>' :'greater',
'>=' :'greater_equal',
}
if expr.rel_op in op:
lhs = self._print(expr.lhs)
rhs = self._print(expr.rhs)
return '{op}({lhs}, {rhs})'.format(op=self._module_format('numpy.'+op[expr.rel_op]),
lhs=lhs, rhs=rhs)
return super(NumPyPrinter, self)._print_Relational(expr)
def _print_And(self, expr):
"Logical And printer"
# We have to override LambdaPrinter because it uses Python 'and' keyword.
# If LambdaPrinter didn't define it, we could use StrPrinter's
# version of the function and add 'logical_and' to NUMPY_TRANSLATIONS.
return '{0}.reduce(({1}))'.format(self._module_format('numpy.logical_and'), ','.join(self._print(i) for i in expr.args))
def _print_Or(self, expr):
"Logical Or printer"
# We have to override LambdaPrinter because it uses Python 'or' keyword.
# If LambdaPrinter didn't define it, we could use StrPrinter's
# version of the function and add 'logical_or' to NUMPY_TRANSLATIONS.
return '{0}.reduce(({1}))'.format(self._module_format('numpy.logical_or'), ','.join(self._print(i) for i in expr.args))
def _print_Not(self, expr):
"Logical Not printer"
# We have to override LambdaPrinter because it uses Python 'not' keyword.
# If LambdaPrinter didn't define it, we would still have to define our
# own because StrPrinter doesn't define it.
return '{0}({1})'.format(self._module_format('numpy.logical_not'), ','.join(self._print(i) for i in expr.args))
def _print_Min(self, expr):
return '{0}(({1}))'.format(self._module_format('numpy.amin'), ','.join(self._print(i) for i in expr.args))
def _print_Max(self, expr):
return '{0}(({1}))'.format(self._module_format('numpy.amax'), ','.join(self._print(i) for i in expr.args))
def _print_Pow(self, expr):
if expr.exp == 0.5:
return '{0}({1})'.format(self._module_format('numpy.sqrt'), self._print(expr.base))
else:
return super(NumPyPrinter, self)._print_Pow(expr)
def _print_arg(self, expr):
return "%s(%s)" % (self._module_format('numpy.angle'), self._print(expr.args[0]))
def _print_im(self, expr):
return "%s(%s)" % (self._module_format('numpy.imag'), self._print(expr.args[0]))
def _print_Mod(self, expr):
return "%s(%s)" % (self._module_format('numpy.mod'), ', '.join(
map(lambda arg: self._print(arg), expr.args)))
def _print_re(self, expr):
return "%s(%s)" % (self._module_format('numpy.real'), self._print(expr.args[0]))
def _print_sinc(self, expr):
return "%s(%s)" % (self._module_format('numpy.sinc'), self._print(expr.args[0]/S.Pi))
def _print_MatrixBase(self, expr):
func = self.known_functions.get(expr.__class__.__name__, None)
if func is None:
func = self._module_format('numpy.array')
return "%s(%s)" % (func, self._print(expr.tolist()))
def _print_CodegenArrayTensorProduct(self, expr):
array_list = [j for i, arg in enumerate(expr.args) for j in
(self._print(arg), "[%i, %i]" % (2*i, 2*i+1))]
return "%s(%s)" % (self._module_format('numpy.einsum'), ", ".join(array_list))
def _print_CodegenArrayContraction(self, expr):
from sympy.codegen.array_utils import CodegenArrayTensorProduct
base = expr.expr
contraction_indices = expr.contraction_indices
if len(contraction_indices) == 0:
return self._print(base)
if isinstance(base, CodegenArrayTensorProduct):
counter = 0
d = {j: min(i) for i in contraction_indices for j in i}
indices = []
for rank_arg in base.subranks:
lindices = []
for i in range(rank_arg):
if counter in d:
lindices.append(d[counter])
else:
lindices.append(counter)
counter += 1
indices.append(lindices)
elems = ["%s, %s" % (self._print(arg), ind) for arg, ind in zip(base.args, indices)]
return "%s(%s)" % (
self._module_format('numpy.einsum'),
", ".join(elems)
)
raise NotImplementedError()
def _print_CodegenArrayDiagonal(self, expr):
diagonal_indices = list(expr.diagonal_indices)
if len(diagonal_indices) > 1:
# TODO: this should be handled in sympy.codegen.array_utils,
# possibly by creating the possibility of unfolding the
# CodegenArrayDiagonal object into nested ones. Same reasoning for
# the array contraction.
raise NotImplementedError
if len(diagonal_indices[0]) != 2:
raise NotImplementedError
return "%s(%s, 0, axis1=%s, axis2=%s)" % (
self._module_format("numpy.diagonal"),
self._print(expr.expr),
diagonal_indices[0][0],
diagonal_indices[0][1],
)
def _print_CodegenArrayPermuteDims(self, expr):
return "%s(%s, %s)" % (
self._module_format("numpy.transpose"),
self._print(expr.expr),
self._print(expr.permutation.args[0]),
)
def _print_CodegenArrayElementwiseAdd(self, expr):
return self._expand_fold_binary_op('numpy.add', expr.args)
for k in NumPyPrinter._kf:
setattr(NumPyPrinter, '_print_%s' % k, _print_known_func)
for k in NumPyPrinter._kc:
setattr(NumPyPrinter, '_print_%s' % k, _print_known_const)
_known_functions_scipy_special = {
'erf': 'erf',
'erfc': 'erfc',
'besselj': 'jv',
'bessely': 'yv',
'besseli': 'iv',
'besselk': 'kv',
'factorial': 'factorial',
'gamma': 'gamma',
'loggamma': 'gammaln',
'digamma': 'psi',
'RisingFactorial': 'poch',
'jacobi': 'eval_jacobi',
'gegenbauer': 'eval_gegenbauer',
'chebyshevt': 'eval_chebyt',
'chebyshevu': 'eval_chebyu',
'legendre': 'eval_legendre',
'hermite': 'eval_hermite',
'laguerre': 'eval_laguerre',
'assoc_laguerre': 'eval_genlaguerre',
}
_known_constants_scipy_constants = {
'GoldenRatio': 'golden_ratio',
'Pi': 'pi',
'E': 'e'
}
class SciPyPrinter(NumPyPrinter):
_kf = dict(chain(
NumPyPrinter._kf.items(),
[(k, 'scipy.special.' + v) for k, v in _known_functions_scipy_special.items()]
))
_kc = {k: 'scipy.constants.' + v for k, v in _known_constants_scipy_constants.items()}
def _print_SparseMatrix(self, expr):
i, j, data = [], [], []
for (r, c), v in expr._smat.items():
i.append(r)
j.append(c)
data.append(v)
return "{name}({data}, ({i}, {j}), shape={shape})".format(
name=self._module_format('scipy.sparse.coo_matrix'),
data=data, i=i, j=j, shape=expr.shape
)
_print_ImmutableSparseMatrix = _print_SparseMatrix
# SciPy's lpmv has a different order of arguments from assoc_legendre
def _print_assoc_legendre(self, expr):
return "{0}({2}, {1}, {3})".format(
self._module_format('scipy.special.lpmv'),
self._print(expr.args[0]),
self._print(expr.args[1]),
self._print(expr.args[2]))
for k in SciPyPrinter._kf:
setattr(SciPyPrinter, '_print_%s' % k, _print_known_func)
for k in SciPyPrinter._kc:
setattr(SciPyPrinter, '_print_%s' % k, _print_known_const)
class SymPyPrinter(PythonCodePrinter):
_kf = dict([(k, 'sympy.' + v) for k, v in chain(
_known_functions.items(),
_known_functions_math.items()
)])
def _print_Function(self, expr):
mod = expr.func.__module__ or ''
return '%s(%s)' % (self._module_format(mod + ('.' if mod else '') + expr.func.__name__),
', '.join(map(lambda arg: self._print(arg), expr.args)))
|
5ff8f315bb7a8582bc2c32fc26d4b347d7d6f7f3f53c71273df56b5c43229387
|
from __future__ import print_function, division
'''
Use llvmlite to create executable functions from Sympy expressions
This module requires llvmlite (https://github.com/numba/llvmlite).
'''
import ctypes
from sympy.external import import_module
from sympy.printing.printer import Printer
from sympy import S, IndexedBase
from sympy.utilities.decorator import doctest_depends_on
llvmlite = import_module('llvmlite')
if llvmlite:
ll = import_module('llvmlite.ir').ir
llvm = import_module('llvmlite.binding').binding
llvm.initialize()
llvm.initialize_native_target()
llvm.initialize_native_asmprinter()
__doctest_requires__ = {('llvm_callable'): ['llvmlite']}
class LLVMJitPrinter(Printer):
'''Convert expressions to LLVM IR'''
def __init__(self, module, builder, fn, *args, **kwargs):
self.func_arg_map = kwargs.pop("func_arg_map", {})
if not llvmlite:
raise ImportError("llvmlite is required for LLVMJITPrinter")
super(LLVMJitPrinter, self).__init__(*args, **kwargs)
self.fp_type = ll.DoubleType()
self.module = module
self.builder = builder
self.fn = fn
self.ext_fn = {} # keep track of wrappers to external functions
self.tmp_var = {}
def _add_tmp_var(self, name, value):
self.tmp_var[name] = value
def _print_Number(self, n):
return ll.Constant(self.fp_type, float(n))
def _print_Integer(self, expr):
return ll.Constant(self.fp_type, float(expr.p))
def _print_Symbol(self, s):
val = self.tmp_var.get(s)
if not val:
# look up parameter with name s
val = self.func_arg_map.get(s)
if not val:
raise LookupError("Symbol not found: %s" % s)
return val
def _print_Pow(self, expr):
base0 = self._print(expr.base)
if expr.exp == S.NegativeOne:
return self.builder.fdiv(ll.Constant(self.fp_type, 1.0), base0)
if expr.exp == S.Half:
fn = self.ext_fn.get("sqrt")
if not fn:
fn_type = ll.FunctionType(self.fp_type, [self.fp_type])
fn = ll.Function(self.module, fn_type, "sqrt")
self.ext_fn["sqrt"] = fn
return self.builder.call(fn, [base0], "sqrt")
if expr.exp == 2:
return self.builder.fmul(base0, base0)
exp0 = self._print(expr.exp)
fn = self.ext_fn.get("pow")
if not fn:
fn_type = ll.FunctionType(self.fp_type, [self.fp_type, self.fp_type])
fn = ll.Function(self.module, fn_type, "pow")
self.ext_fn["pow"] = fn
return self.builder.call(fn, [base0, exp0], "pow")
def _print_Mul(self, expr):
nodes = [self._print(a) for a in expr.args]
e = nodes[0]
for node in nodes[1:]:
e = self.builder.fmul(e, node)
return e
def _print_Add(self, expr):
nodes = [self._print(a) for a in expr.args]
e = nodes[0]
for node in nodes[1:]:
e = self.builder.fadd(e, node)
return e
# TODO - assumes all called functions take one double precision argument.
# Should have a list of math library functions to validate this.
def _print_Function(self, expr):
name = expr.func.__name__
e0 = self._print(expr.args[0])
fn = self.ext_fn.get(name)
if not fn:
fn_type = ll.FunctionType(self.fp_type, [self.fp_type])
fn = ll.Function(self.module, fn_type, name)
self.ext_fn[name] = fn
return self.builder.call(fn, [e0], name)
def emptyPrinter(self, expr):
raise TypeError("Unsupported type for LLVM JIT conversion: %s"
% type(expr))
# Used when parameters are passed by array. Often used in callbacks to
# handle a variable number of parameters.
class LLVMJitCallbackPrinter(LLVMJitPrinter):
def __init__(self, *args, **kwargs):
super(LLVMJitCallbackPrinter, self).__init__(*args, **kwargs)
def _print_Indexed(self, expr):
array, idx = self.func_arg_map[expr.base]
offset = int(expr.indices[0].evalf())
array_ptr = self.builder.gep(array, [ll.Constant(ll.IntType(32), offset)])
fp_array_ptr = self.builder.bitcast(array_ptr, ll.PointerType(self.fp_type))
value = self.builder.load(fp_array_ptr)
return value
def _print_Symbol(self, s):
val = self.tmp_var.get(s)
if val:
return val
array, idx = self.func_arg_map.get(s, [None, 0])
if not array:
raise LookupError("Symbol not found: %s" % s)
array_ptr = self.builder.gep(array, [ll.Constant(ll.IntType(32), idx)])
fp_array_ptr = self.builder.bitcast(array_ptr,
ll.PointerType(self.fp_type))
value = self.builder.load(fp_array_ptr)
return value
# ensure lifetime of the execution engine persists (else call to compiled
# function will seg fault)
exe_engines = []
# ensure names for generated functions are unique
link_names = set()
current_link_suffix = 0
class LLVMJitCode(object):
def __init__(self, signature):
self.signature = signature
self.fp_type = ll.DoubleType()
self.module = ll.Module('mod1')
self.fn = None
self.llvm_arg_types = []
self.llvm_ret_type = self.fp_type
self.param_dict = {} # map symbol name to LLVM function argument
self.link_name = ''
def _from_ctype(self, ctype):
if ctype == ctypes.c_int:
return ll.IntType(32)
if ctype == ctypes.c_double:
return self.fp_type
if ctype == ctypes.POINTER(ctypes.c_double):
return ll.PointerType(self.fp_type)
if ctype == ctypes.c_void_p:
return ll.PointerType(ll.IntType(32))
if ctype == ctypes.py_object:
return ll.PointerType(ll.IntType(32))
print("Unhandled ctype = %s" % str(ctype))
def _create_args(self, func_args):
"""Create types for function arguments"""
self.llvm_ret_type = self._from_ctype(self.signature.ret_type)
self.llvm_arg_types = \
[self._from_ctype(a) for a in self.signature.arg_ctypes]
def _create_function_base(self):
"""Create function with name and type signature"""
global link_names, current_link_suffix
default_link_name = 'jit_func'
current_link_suffix += 1
self.link_name = default_link_name + str(current_link_suffix)
link_names.add(self.link_name)
fn_type = ll.FunctionType(self.llvm_ret_type, self.llvm_arg_types)
self.fn = ll.Function(self.module, fn_type, name=self.link_name)
def _create_param_dict(self, func_args):
"""Mapping of symbolic values to function arguments"""
for i, a in enumerate(func_args):
self.fn.args[i].name = str(a)
self.param_dict[a] = self.fn.args[i]
def _create_function(self, expr):
"""Create function body and return LLVM IR"""
bb_entry = self.fn.append_basic_block('entry')
builder = ll.IRBuilder(bb_entry)
lj = LLVMJitPrinter(self.module, builder, self.fn,
func_arg_map=self.param_dict)
ret = self._convert_expr(lj, expr)
lj.builder.ret(self._wrap_return(lj, ret))
strmod = str(self.module)
return strmod
def _wrap_return(self, lj, vals):
# Return a single double if there is one return value,
# else return a tuple of doubles.
# Don't wrap return value in this case
if self.signature.ret_type == ctypes.c_double:
return vals[0]
# Use this instead of a real PyObject*
void_ptr = ll.PointerType(ll.IntType(32))
# Create a wrapped double: PyObject* PyFloat_FromDouble(double v)
wrap_type = ll.FunctionType(void_ptr, [self.fp_type])
wrap_fn = ll.Function(lj.module, wrap_type, "PyFloat_FromDouble")
wrapped_vals = [lj.builder.call(wrap_fn, [v]) for v in vals]
if len(vals) == 1:
final_val = wrapped_vals[0]
else:
# Create a tuple: PyObject* PyTuple_Pack(Py_ssize_t n, ...)
# This should be Py_ssize_t
tuple_arg_types = [ll.IntType(32)]
tuple_arg_types.extend([void_ptr]*len(vals))
tuple_type = ll.FunctionType(void_ptr, tuple_arg_types)
tuple_fn = ll.Function(lj.module, tuple_type, "PyTuple_Pack")
tuple_args = [ll.Constant(ll.IntType(32), len(wrapped_vals))]
tuple_args.extend(wrapped_vals)
final_val = lj.builder.call(tuple_fn, tuple_args)
return final_val
def _convert_expr(self, lj, expr):
try:
# Match CSE return data structure.
if len(expr) == 2:
tmp_exprs = expr[0]
final_exprs = expr[1]
if len(final_exprs) != 1 and self.signature.ret_type == ctypes.c_double:
raise NotImplementedError("Return of multiple expressions not supported for this callback")
for name, e in tmp_exprs:
val = lj._print(e)
lj._add_tmp_var(name, val)
except TypeError:
final_exprs = [expr]
vals = [lj._print(e) for e in final_exprs]
return vals
def _compile_function(self, strmod):
global exe_engines
llmod = llvm.parse_assembly(strmod)
pmb = llvm.create_pass_manager_builder()
pmb.opt_level = 2
pass_manager = llvm.create_module_pass_manager()
pmb.populate(pass_manager)
pass_manager.run(llmod)
target_machine = \
llvm.Target.from_default_triple().create_target_machine()
exe_eng = llvm.create_mcjit_compiler(llmod, target_machine)
exe_eng.finalize_object()
exe_engines.append(exe_eng)
if False:
print("Assembly")
print(target_machine.emit_assembly(llmod))
fptr = exe_eng.get_function_address(self.link_name)
return fptr
class LLVMJitCodeCallback(LLVMJitCode):
def __init__(self, signature):
super(LLVMJitCodeCallback, self).__init__(signature)
def _create_param_dict(self, func_args):
for i, a in enumerate(func_args):
if isinstance(a, IndexedBase):
self.param_dict[a] = (self.fn.args[i], i)
self.fn.args[i].name = str(a)
else:
self.param_dict[a] = (self.fn.args[self.signature.input_arg],
i)
def _create_function(self, expr):
"""Create function body and return LLVM IR"""
bb_entry = self.fn.append_basic_block('entry')
builder = ll.IRBuilder(bb_entry)
lj = LLVMJitCallbackPrinter(self.module, builder, self.fn,
func_arg_map=self.param_dict)
ret = self._convert_expr(lj, expr)
if self.signature.ret_arg:
output_fp_ptr = builder.bitcast(self.fn.args[self.signature.ret_arg],
ll.PointerType(self.fp_type))
for i, val in enumerate(ret):
index = ll.Constant(ll.IntType(32), i)
output_array_ptr = builder.gep(output_fp_ptr, [index])
builder.store(val, output_array_ptr)
builder.ret(ll.Constant(ll.IntType(32), 0)) # return success
else:
lj.builder.ret(self._wrap_return(lj, ret))
strmod = str(self.module)
return strmod
class CodeSignature(object):
def __init__(self, ret_type):
self.ret_type = ret_type
self.arg_ctypes = []
# Input argument array element index
self.input_arg = 0
# For the case output value is referenced through a parameter rather
# than the return value
self.ret_arg = None
def _llvm_jit_code(args, expr, signature, callback_type):
"""Create a native code function from a Sympy expression"""
if callback_type is None:
jit = LLVMJitCode(signature)
else:
jit = LLVMJitCodeCallback(signature)
jit._create_args(args)
jit._create_function_base()
jit._create_param_dict(args)
strmod = jit._create_function(expr)
if False:
print("LLVM IR")
print(strmod)
fptr = jit._compile_function(strmod)
return fptr
@doctest_depends_on(modules=('llvmlite', 'scipy'))
def llvm_callable(args, expr, callback_type=None):
'''Compile function from a Sympy expression
Expressions are evaluated using double precision arithmetic.
Some single argument math functions (exp, sin, cos, etc.) are supported
in expressions.
Parameters
==========
args : List of Symbol
Arguments to the generated function. Usually the free symbols in
the expression. Currently each one is assumed to convert to
a double precision scalar.
expr : Expr, or (Replacements, Expr) as returned from 'cse'
Expression to compile.
callback_type : string
Create function with signature appropriate to use as a callback.
Currently supported:
'scipy.integrate'
'scipy.integrate.test'
'cubature'
Returns
=======
Compiled function that can evaluate the expression.
Examples
========
>>> import sympy.printing.llvmjitcode as jit
>>> from sympy.abc import a
>>> e = a*a + a + 1
>>> e1 = jit.llvm_callable([a], e)
>>> e.subs(a, 1.1) # Evaluate via substitution
3.31000000000000
>>> e1(1.1) # Evaluate using JIT-compiled code
3.3100000000000005
Callbacks for integration functions can be JIT compiled.
>>> import sympy.printing.llvmjitcode as jit
>>> from sympy.abc import a
>>> from sympy import integrate
>>> from scipy.integrate import quad
>>> e = a*a
>>> e1 = jit.llvm_callable([a], e, callback_type='scipy.integrate')
>>> integrate(e, (a, 0.0, 2.0))
2.66666666666667
>>> quad(e1, 0.0, 2.0)[0]
2.66666666666667
The 'cubature' callback is for the Python wrapper around the
cubature package ( https://github.com/saullocastro/cubature )
and ( http://ab-initio.mit.edu/wiki/index.php/Cubature )
There are two signatures for the SciPy integration callbacks.
The first ('scipy.integrate') is the function to be passed to the
integration routine, and will pass the signature checks.
The second ('scipy.integrate.test') is only useful for directly calling
the function using ctypes variables. It will not pass the signature checks
for scipy.integrate.
The return value from the cse module can also be compiled. This
can improve the performance of the compiled function. If multiple
expressions are given to cse, the compiled function returns a tuple.
The 'cubature' callback handles multiple expressions (set `fdim`
to match in the integration call.)
>>> import sympy.printing.llvmjitcode as jit
>>> from sympy import cse, exp
>>> from sympy.abc import x,y
>>> e1 = x*x + y*y
>>> e2 = 4*(x*x + y*y) + 8.0
>>> after_cse = cse([e1,e2])
>>> after_cse
([(x0, x**2), (x1, y**2)], [x0 + x1, 4*x0 + 4*x1 + 8.0])
>>> j1 = jit.llvm_callable([x,y], after_cse)
>>> j1(1.0, 2.0)
(5.0, 28.0)
'''
if not llvmlite:
raise ImportError("llvmlite is required for llvmjitcode")
signature = CodeSignature(ctypes.py_object)
arg_ctypes = []
if callback_type is None:
for arg in args:
arg_ctype = ctypes.c_double
arg_ctypes.append(arg_ctype)
elif callback_type == 'scipy.integrate' or callback_type == 'scipy.integrate.test':
signature.ret_type = ctypes.c_double
arg_ctypes = [ctypes.c_int, ctypes.POINTER(ctypes.c_double)]
arg_ctypes_formal = [ctypes.c_int, ctypes.c_double]
signature.input_arg = 1
elif callback_type == 'cubature':
arg_ctypes = [ctypes.c_int,
ctypes.POINTER(ctypes.c_double),
ctypes.c_void_p,
ctypes.c_int,
ctypes.POINTER(ctypes.c_double)
]
signature.ret_type = ctypes.c_int
signature.input_arg = 1
signature.ret_arg = 4
else:
raise ValueError("Unknown callback type: %s" % callback_type)
signature.arg_ctypes = arg_ctypes
fptr = _llvm_jit_code(args, expr, signature, callback_type)
if callback_type and callback_type == 'scipy.integrate':
arg_ctypes = arg_ctypes_formal
cfunc = ctypes.CFUNCTYPE(signature.ret_type, *arg_ctypes)(fptr)
return cfunc
|
3e14aee5300ca4d8a611408178062ace8045ae2c2d0bb7560cc899d6a78ebdc0
|
"""
A Printer which converts an expression into its LaTeX equivalent.
"""
from __future__ import print_function, division
import itertools
from sympy.core import S, Add, Symbol, Mod
from sympy.core.sympify import SympifyError
from sympy.core.alphabets import greeks
from sympy.core.operations import AssocOp
from sympy.core.containers import Tuple
from sympy.logic.boolalg import true
from sympy.core.function import (_coeff_isneg,
UndefinedFunction, AppliedUndef, Derivative)
## sympy.printing imports
from sympy.printing.precedence import precedence_traditional
from .printer import Printer
from .conventions import split_super_sub, requires_partial
from .precedence import precedence, PRECEDENCE
import mpmath.libmp as mlib
from mpmath.libmp import prec_to_dps
from sympy.core.compatibility import default_sort_key, range
from sympy.utilities.iterables import has_variety
import re
# Hand-picked functions which can be used directly in both LaTeX and MathJax
# Complete list at http://www.mathjax.org/docs/1.1/tex.html#supported-latex-commands
# This variable only contains those functions which sympy uses.
accepted_latex_functions = ['arcsin', 'arccos', 'arctan', 'sin', 'cos', 'tan',
'sinh', 'cosh', 'tanh', 'sqrt', 'ln', 'log', 'sec', 'csc',
'cot', 'coth', 're', 'im', 'frac', 'root', 'arg',
]
tex_greek_dictionary = {
'Alpha': 'A',
'Beta': 'B',
'Gamma': r'\Gamma',
'Delta': r'\Delta',
'Epsilon': 'E',
'Zeta': 'Z',
'Eta': 'H',
'Theta': r'\Theta',
'Iota': 'I',
'Kappa': 'K',
'Lambda': r'\Lambda',
'Mu': 'M',
'Nu': 'N',
'Xi': r'\Xi',
'omicron': 'o',
'Omicron': 'O',
'Pi': r'\Pi',
'Rho': 'P',
'Sigma': r'\Sigma',
'Tau': 'T',
'Upsilon': r'\Upsilon',
'Phi': r'\Phi',
'Chi': 'X',
'Psi': r'\Psi',
'Omega': r'\Omega',
'lamda': r'\lambda',
'Lamda': r'\Lambda',
'khi': r'\chi',
'Khi': r'X',
'varepsilon': r'\varepsilon',
'varkappa': r'\varkappa',
'varphi': r'\varphi',
'varpi': r'\varpi',
'varrho': r'\varrho',
'varsigma': r'\varsigma',
'vartheta': r'\vartheta',
}
other_symbols = set(['aleph', 'beth', 'daleth', 'gimel', 'ell', 'eth', 'hbar',
'hslash', 'mho', 'wp', ])
# Variable name modifiers
modifier_dict = {
# Accents
'mathring': lambda s: r'\mathring{'+s+r'}',
'ddddot': lambda s: r'\ddddot{'+s+r'}',
'dddot': lambda s: r'\dddot{'+s+r'}',
'ddot': lambda s: r'\ddot{'+s+r'}',
'dot': lambda s: r'\dot{'+s+r'}',
'check': lambda s: r'\check{'+s+r'}',
'breve': lambda s: r'\breve{'+s+r'}',
'acute': lambda s: r'\acute{'+s+r'}',
'grave': lambda s: r'\grave{'+s+r'}',
'tilde': lambda s: r'\tilde{'+s+r'}',
'hat': lambda s: r'\hat{'+s+r'}',
'bar': lambda s: r'\bar{'+s+r'}',
'vec': lambda s: r'\vec{'+s+r'}',
'prime': lambda s: "{"+s+"}'",
'prm': lambda s: "{"+s+"}'",
# Faces
'bold': lambda s: r'\boldsymbol{'+s+r'}',
'bm': lambda s: r'\boldsymbol{'+s+r'}',
'cal': lambda s: r'\mathcal{'+s+r'}',
'scr': lambda s: r'\mathscr{'+s+r'}',
'frak': lambda s: r'\mathfrak{'+s+r'}',
# Brackets
'norm': lambda s: r'\left\|{'+s+r'}\right\|',
'avg': lambda s: r'\left\langle{'+s+r'}\right\rangle',
'abs': lambda s: r'\left|{'+s+r'}\right|',
'mag': lambda s: r'\left|{'+s+r'}\right|',
}
greek_letters_set = frozenset(greeks)
_between_two_numbers_p = (
re.compile(r'[0-9][} ]*$'), # search
re.compile(r'[{ ]*[-+0-9]'), # match
)
class LatexPrinter(Printer):
printmethod = "_latex"
_default_settings = {
"order": None,
"mode": "plain",
"itex": False,
"fold_frac_powers": False,
"fold_func_brackets": False,
"fold_short_frac": None,
"long_frac_ratio": None,
"mul_symbol": None,
"inv_trig_style": "abbreviated",
"mat_str": None,
"mat_delim": "[",
"symbol_names": {},
"ln_notation": False,
}
def __init__(self, settings=None):
Printer.__init__(self, settings)
if 'mode' in self._settings:
valid_modes = ['inline', 'plain', 'equation',
'equation*']
if self._settings['mode'] not in valid_modes:
raise ValueError("'mode' must be one of 'inline', 'plain', "
"'equation' or 'equation*'")
if self._settings['fold_short_frac'] is None and \
self._settings['mode'] == 'inline':
self._settings['fold_short_frac'] = True
mul_symbol_table = {
None: r" ",
"ldot": r" \,.\, ",
"dot": r" \cdot ",
"times": r" \times "
}
try:
self._settings['mul_symbol_latex'] = \
mul_symbol_table[self._settings['mul_symbol']]
except KeyError:
self._settings['mul_symbol_latex'] = \
self._settings['mul_symbol']
try:
self._settings['mul_symbol_latex_numbers'] = \
mul_symbol_table[self._settings['mul_symbol'] or 'dot']
except KeyError:
if (self._settings['mul_symbol'].strip() in
['', ' ', '\\', '\\,', '\\:', '\\;', '\\quad']):
self._settings['mul_symbol_latex_numbers'] = \
mul_symbol_table['dot']
else:
self._settings['mul_symbol_latex_numbers'] = \
self._settings['mul_symbol']
self._delim_dict = {'(': ')', '[': ']'}
def parenthesize(self, item, level, strict=False):
prec_val = precedence_traditional(item)
if (prec_val < level) or ((not strict) and prec_val <= level):
return r"\left(%s\right)" % self._print(item)
else:
return self._print(item)
def doprint(self, expr):
tex = Printer.doprint(self, expr)
if self._settings['mode'] == 'plain':
return tex
elif self._settings['mode'] == 'inline':
return r"$%s$" % tex
elif self._settings['itex']:
return r"$$%s$$" % tex
else:
env_str = self._settings['mode']
return r"\begin{%s}%s\end{%s}" % (env_str, tex, env_str)
def _needs_brackets(self, expr):
"""
Returns True if the expression needs to be wrapped in brackets when
printed, False otherwise. For example: a + b => True; a => False;
10 => False; -10 => True.
"""
return not ((expr.is_Integer and expr.is_nonnegative)
or (expr.is_Atom and (expr is not S.NegativeOne
and expr.is_Rational is False)))
def _needs_function_brackets(self, expr):
"""
Returns True if the expression needs to be wrapped in brackets when
passed as an argument to a function, False otherwise. This is a more
liberal version of _needs_brackets, in that many expressions which need
to be wrapped in brackets when added/subtracted/raised to a power do
not need them when passed to a function. Such an example is a*b.
"""
if not self._needs_brackets(expr):
return False
else:
# Muls of the form a*b*c... can be folded
if expr.is_Mul and not self._mul_is_clean(expr):
return True
# Pows which don't need brackets can be folded
elif expr.is_Pow and not self._pow_is_clean(expr):
return True
# Add and Function always need brackets
elif expr.is_Add or expr.is_Function:
return True
else:
return False
def _needs_mul_brackets(self, expr, first=False, last=False):
"""
Returns True if the expression needs to be wrapped in brackets when
printed as part of a Mul, False otherwise. This is True for Add,
but also for some container objects that would not need brackets
when appearing last in a Mul, e.g. an Integral. ``last=True``
specifies that this expr is the last to appear in a Mul.
``first=True`` specifies that this expr is the first to appear in a Mul.
"""
from sympy import Integral, Piecewise, Product, Sum
if expr.is_Mul:
if not first and _coeff_isneg(expr):
return True
elif precedence_traditional(expr) < PRECEDENCE["Mul"]:
return True
elif expr.is_Relational:
return True
if expr.is_Piecewise:
return True
if any([expr.has(x) for x in (Mod,)]):
return True
if (not last and
any([expr.has(x) for x in (Integral, Product, Sum)])):
return True
return False
def _needs_add_brackets(self, expr):
"""
Returns True if the expression needs to be wrapped in brackets when
printed as part of an Add, False otherwise. This is False for most
things.
"""
if expr.is_Relational:
return True
if any([expr.has(x) for x in (Mod,)]):
return True
if expr.is_Add:
return True
return False
def _mul_is_clean(self, expr):
for arg in expr.args:
if arg.is_Function:
return False
return True
def _pow_is_clean(self, expr):
return not self._needs_brackets(expr.base)
def _do_exponent(self, expr, exp):
if exp is not None:
return r"\left(%s\right)^{%s}" % (expr, exp)
else:
return expr
def _print_Basic(self, expr):
l = [self._print(o) for o in expr.args]
return self._deal_with_super_sub(expr.__class__.__name__) + r"\left(%s\right)" % ", ".join(l)
def _print_bool(self, e):
return r"\mathrm{%s}" % e
_print_BooleanTrue = _print_bool
_print_BooleanFalse = _print_bool
def _print_NoneType(self, e):
return r"\mathrm{%s}" % e
def _print_Add(self, expr, order=None):
if self.order == 'none':
terms = list(expr.args)
else:
terms = self._as_ordered_terms(expr, order=order)
tex = ""
for i, term in enumerate(terms):
if i == 0:
pass
elif _coeff_isneg(term):
tex += " - "
term = -term
else:
tex += " + "
term_tex = self._print(term)
if self._needs_add_brackets(term):
term_tex = r"\left(%s\right)" % term_tex
tex += term_tex
return tex
def _print_Cycle(self, expr):
from sympy.combinatorics.permutations import Permutation
if expr.size == 0:
return r"\left( \right)"
expr = Permutation(expr)
expr_perm = expr.cyclic_form
siz = expr.size
if expr.array_form[-1] == siz - 1:
expr_perm = expr_perm + [[siz - 1]]
term_tex = ''
for i in expr_perm:
term_tex += str(i).replace(',', r"\;")
term_tex = term_tex.replace('[', r"\left( ")
term_tex = term_tex.replace(']', r"\right)")
return term_tex
_print_Permutation = _print_Cycle
def _print_Float(self, expr):
# Based off of that in StrPrinter
dps = prec_to_dps(expr._prec)
str_real = mlib.to_str(expr._mpf_, dps, strip_zeros=True)
# Must always have a mul symbol (as 2.5 10^{20} just looks odd)
# thus we use the number separator
separator = self._settings['mul_symbol_latex_numbers']
if 'e' in str_real:
(mant, exp) = str_real.split('e')
if exp[0] == '+':
exp = exp[1:]
return r"%s%s10^{%s}" % (mant, separator, exp)
elif str_real == "+inf":
return r"\infty"
elif str_real == "-inf":
return r"- \infty"
else:
return str_real
def _print_Cross(self, expr):
vec1 = expr._expr1
vec2 = expr._expr2
return r"%s \times %s" % (self.parenthesize(vec1, PRECEDENCE['Mul']),
self.parenthesize(vec2, PRECEDENCE['Mul']))
def _print_Curl(self, expr):
vec = expr._expr
return r"\nabla\times %s" % self.parenthesize(vec, PRECEDENCE['Mul'])
def _print_Divergence(self, expr):
vec = expr._expr
return r"\nabla\cdot %s" % self.parenthesize(vec, PRECEDENCE['Mul'])
def _print_Dot(self, expr):
vec1 = expr._expr1
vec2 = expr._expr2
return r"%s \cdot %s" % (self.parenthesize(vec1, PRECEDENCE['Mul']),
self.parenthesize(vec2, PRECEDENCE['Mul']))
def _print_Gradient(self, expr):
func = expr._expr
return r"\nabla\cdot %s" % self.parenthesize(func, PRECEDENCE['Mul'])
def _print_Mul(self, expr):
from sympy.core.power import Pow
from sympy.physics.units import Quantity
include_parens = False
if _coeff_isneg(expr):
expr = -expr
tex = "- "
if expr.is_Add:
tex += "("
include_parens = True
else:
tex = ""
from sympy.simplify import fraction
numer, denom = fraction(expr, exact=True)
separator = self._settings['mul_symbol_latex']
numbersep = self._settings['mul_symbol_latex_numbers']
def convert(expr):
if not expr.is_Mul:
return str(self._print(expr))
else:
_tex = last_term_tex = ""
if self.order not in ('old', 'none'):
args = expr.as_ordered_factors()
else:
args = list(expr.args)
# If quantities are present append them at the back
args = sorted(args, key=lambda x: isinstance(x, Quantity) or
(isinstance(x, Pow) and isinstance(x.base, Quantity)))
for i, term in enumerate(args):
term_tex = self._print(term)
if self._needs_mul_brackets(term, first=(i == 0),
last=(i == len(args) - 1)):
term_tex = r"\left(%s\right)" % term_tex
if _between_two_numbers_p[0].search(last_term_tex) and \
_between_two_numbers_p[1].match(term_tex):
# between two numbers
_tex += numbersep
elif _tex:
_tex += separator
_tex += term_tex
last_term_tex = term_tex
return _tex
if denom is S.One and Pow(1, -1, evaluate=False) not in expr.args:
# use the original expression here, since fraction() may have
# altered it when producing numer and denom
tex += convert(expr)
else:
snumer = convert(numer)
sdenom = convert(denom)
ldenom = len(sdenom.split())
ratio = self._settings['long_frac_ratio']
if self._settings['fold_short_frac'] \
and ldenom <= 2 and not "^" in sdenom:
# handle short fractions
if self._needs_mul_brackets(numer, last=False):
tex += r"\left(%s\right) / %s" % (snumer, sdenom)
else:
tex += r"%s / %s" % (snumer, sdenom)
elif ratio is not None and \
len(snumer.split()) > ratio*ldenom:
# handle long fractions
if self._needs_mul_brackets(numer, last=True):
tex += r"\frac{1}{%s}%s\left(%s\right)" \
% (sdenom, separator, snumer)
elif numer.is_Mul:
# split a long numerator
a = S.One
b = S.One
for x in numer.args:
if self._needs_mul_brackets(x, last=False) or \
len(convert(a*x).split()) > ratio*ldenom or \
(b.is_commutative is x.is_commutative is False):
b *= x
else:
a *= x
if self._needs_mul_brackets(b, last=True):
tex += r"\frac{%s}{%s}%s\left(%s\right)" \
% (convert(a), sdenom, separator, convert(b))
else:
tex += r"\frac{%s}{%s}%s%s" \
% (convert(a), sdenom, separator, convert(b))
else:
tex += r"\frac{1}{%s}%s%s" % (sdenom, separator, snumer)
else:
tex += r"\frac{%s}{%s}" % (snumer, sdenom)
if include_parens:
tex += ")"
return tex
def _print_Pow(self, expr):
# Treat x**Rational(1,n) as special case
if expr.exp.is_Rational and abs(expr.exp.p) == 1 and expr.exp.q != 1:
base = self._print(expr.base)
expq = expr.exp.q
if expq == 2:
tex = r"\sqrt{%s}" % base
elif self._settings['itex']:
tex = r"\root{%d}{%s}" % (expq, base)
else:
tex = r"\sqrt[%d]{%s}" % (expq, base)
if expr.exp.is_negative:
return r"\frac{1}{%s}" % tex
else:
return tex
elif self._settings['fold_frac_powers'] \
and expr.exp.is_Rational \
and expr.exp.q != 1:
base, p, q = self.parenthesize(expr.base, PRECEDENCE['Pow']), expr.exp.p, expr.exp.q
# issue #12886: add parentheses for superscripts raised to powers
if '^' in base and expr.base.is_Symbol:
base = r"\left(%s\right)" % base
if expr.base.is_Function:
return self._print(expr.base, exp="%s/%s" % (p, q))
return r"%s^{%s/%s}" % (base, p, q)
elif expr.exp.is_Rational and expr.exp.is_negative and expr.base.is_commutative:
# special case for 1^(-x), issue 9216
if expr.base == 1:
return r"%s^{%s}" % (expr.base, expr.exp)
# things like 1/x
return self._print_Mul(expr)
else:
if expr.base.is_Function:
return self._print(expr.base, exp=self._print(expr.exp))
else:
tex = r"%s^{%s}"
exp = self._print(expr.exp)
# issue #12886: add parentheses around superscripts raised to powers
base = self.parenthesize(expr.base, PRECEDENCE['Pow'])
if '^' in base and expr.base.is_Symbol:
base = r"\left(%s\right)" % base
elif isinstance(expr.base, Derivative
) and base.startswith(r'\left('
) and re.match(r'\\left\(\\d?d?dot', base
) and base.endswith(r'\right)'):
# don't use parentheses around dotted derivative
base = base[6: -7] # remove outermost added parens
return tex % (base, exp)
def _print_UnevaluatedExpr(self, expr):
return self._print(expr.args[0])
def _print_Sum(self, expr):
if len(expr.limits) == 1:
tex = r"\sum_{%s=%s}^{%s} " % \
tuple([ self._print(i) for i in expr.limits[0] ])
else:
def _format_ineq(l):
return r"%s \leq %s \leq %s" % \
tuple([self._print(s) for s in (l[1], l[0], l[2])])
tex = r"\sum_{\substack{%s}} " % \
str.join('\\\\', [ _format_ineq(l) for l in expr.limits ])
if isinstance(expr.function, Add):
tex += r"\left(%s\right)" % self._print(expr.function)
else:
tex += self._print(expr.function)
return tex
def _print_Product(self, expr):
if len(expr.limits) == 1:
tex = r"\prod_{%s=%s}^{%s} " % \
tuple([ self._print(i) for i in expr.limits[0] ])
else:
def _format_ineq(l):
return r"%s \leq %s \leq %s" % \
tuple([self._print(s) for s in (l[1], l[0], l[2])])
tex = r"\prod_{\substack{%s}} " % \
str.join('\\\\', [ _format_ineq(l) for l in expr.limits ])
if isinstance(expr.function, Add):
tex += r"\left(%s\right)" % self._print(expr.function)
else:
tex += self._print(expr.function)
return tex
def _print_BasisDependent(self, expr):
from sympy.vector import Vector
o1 = []
if expr == expr.zero:
return expr.zero._latex_form
if isinstance(expr, Vector):
items = expr.separate().items()
else:
items = [(0, expr)]
for system, vect in items:
inneritems = list(vect.components.items())
inneritems.sort(key = lambda x:x[0].__str__())
for k, v in inneritems:
if v == 1:
o1.append(' + ' + k._latex_form)
elif v == -1:
o1.append(' - ' + k._latex_form)
else:
arg_str = '(' + LatexPrinter().doprint(v) + ')'
o1.append(' + ' + arg_str + k._latex_form)
outstr = (''.join(o1))
if outstr[1] != '-':
outstr = outstr[3:]
else:
outstr = outstr[1:]
return outstr
def _print_Indexed(self, expr):
tex_base = self._print(expr.base)
tex = '{'+tex_base+'}'+'_{%s}' % ','.join(
map(self._print, expr.indices))
return tex
def _print_IndexedBase(self, expr):
return self._print(expr.label)
def _print_Derivative(self, expr):
if requires_partial(expr):
diff_symbol = r'\partial'
else:
diff_symbol = r'd'
tex = ""
dim = 0
for x, num in reversed(expr.variable_count):
dim += num
if num == 1:
tex += r"%s %s" % (diff_symbol, self._print(x))
else:
tex += r"%s %s^{%s}" % (diff_symbol, self._print(x), num)
if dim == 1:
tex = r"\frac{%s}{%s}" % (diff_symbol, tex)
else:
tex = r"\frac{%s^{%s}}{%s}" % (diff_symbol, dim, tex)
return r"%s %s" % (tex, self.parenthesize(expr.expr, PRECEDENCE["Mul"], strict=True))
def _print_Subs(self, subs):
expr, old, new = subs.args
latex_expr = self._print(expr)
latex_old = (self._print(e) for e in old)
latex_new = (self._print(e) for e in new)
latex_subs = r'\\ '.join(
e[0] + '=' + e[1] for e in zip(latex_old, latex_new))
return r'\left. %s \right|_{\substack{ %s }}' % (latex_expr, latex_subs)
def _print_Integral(self, expr):
tex, symbols = "", []
# Only up to \iiiint exists
if len(expr.limits) <= 4 and all(len(lim) == 1 for lim in expr.limits):
# Use len(expr.limits)-1 so that syntax highlighters don't think
# \" is an escaped quote
tex = r"\i" + "i"*(len(expr.limits) - 1) + "nt"
symbols = [r"\, d%s" % self._print(symbol[0])
for symbol in expr.limits]
else:
for lim in reversed(expr.limits):
symbol = lim[0]
tex += r"\int"
if len(lim) > 1:
if self._settings['mode'] != 'inline' \
and not self._settings['itex']:
tex += r"\limits"
if len(lim) == 3:
tex += "_{%s}^{%s}" % (self._print(lim[1]),
self._print(lim[2]))
if len(lim) == 2:
tex += "^{%s}" % (self._print(lim[1]))
symbols.insert(0, r"\, d%s" % self._print(symbol))
return r"%s %s%s" % (tex,
self.parenthesize(expr.function, PRECEDENCE["Mul"], strict=True), "".join(symbols))
def _print_Limit(self, expr):
e, z, z0, dir = expr.args
tex = r"\lim_{%s \to " % self._print(z)
if str(dir) == '+-' or z0 in (S.Infinity, S.NegativeInfinity):
tex += r"%s}" % self._print(z0)
else:
tex += r"%s^%s}" % (self._print(z0), self._print(dir))
if isinstance(e, AssocOp):
return r"%s\left(%s\right)" % (tex, self._print(e))
else:
return r"%s %s" % (tex, self._print(e))
def _hprint_Function(self, func):
r'''
Logic to decide how to render a function to latex
- if it is a recognized latex name, use the appropriate latex command
- if it is a single letter, just use that letter
- if it is a longer name, then put \operatorname{} around it and be
mindful of undercores in the name
'''
func = self._deal_with_super_sub(func)
if func in accepted_latex_functions:
name = r"\%s" % func
elif len(func) == 1 or func.startswith('\\'):
name = func
else:
name = r"\operatorname{%s}" % func
return name
def _print_Function(self, expr, exp=None):
r'''
Render functions to LaTeX, handling functions that LaTeX knows about
e.g., sin, cos, ... by using the proper LaTeX command (\sin, \cos, ...).
For single-letter function names, render them as regular LaTeX math
symbols. For multi-letter function names that LaTeX does not know
about, (e.g., Li, sech) use \operatorname{} so that the function name
is rendered in Roman font and LaTeX handles spacing properly.
expr is the expression involving the function
exp is an exponent
'''
func = expr.func.__name__
if hasattr(self, '_print_' + func) and \
not isinstance(expr, AppliedUndef):
return getattr(self, '_print_' + func)(expr, exp)
else:
args = [ str(self._print(arg)) for arg in expr.args ]
# How inverse trig functions should be displayed, formats are:
# abbreviated: asin, full: arcsin, power: sin^-1
inv_trig_style = self._settings['inv_trig_style']
# If we are dealing with a power-style inverse trig function
inv_trig_power_case = False
# If it is applicable to fold the argument brackets
can_fold_brackets = self._settings['fold_func_brackets'] and \
len(args) == 1 and \
not self._needs_function_brackets(expr.args[0])
inv_trig_table = ["asin", "acos", "atan", "acsc", "asec", "acot"]
# If the function is an inverse trig function, handle the style
if func in inv_trig_table:
if inv_trig_style == "abbreviated":
func = func
elif inv_trig_style == "full":
func = "arc" + func[1:]
elif inv_trig_style == "power":
func = func[1:]
inv_trig_power_case = True
# Can never fold brackets if we're raised to a power
if exp is not None:
can_fold_brackets = False
if inv_trig_power_case:
if func in accepted_latex_functions:
name = r"\%s^{-1}" % func
else:
name = r"\operatorname{%s}^{-1}" % func
elif exp is not None:
name = r'%s^{%s}' % (self._hprint_Function(func), exp)
else:
name = self._hprint_Function(func)
if can_fold_brackets:
if func in accepted_latex_functions:
# Wrap argument safely to avoid parse-time conflicts
# with the function name itself
name += r" {%s}"
else:
name += r"%s"
else:
name += r"{\left (%s \right )}"
if inv_trig_power_case and exp is not None:
name += r"^{%s}" % exp
return name % ",".join(args)
def _print_UndefinedFunction(self, expr):
return self._hprint_Function(str(expr))
@property
def _special_function_classes(self):
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.functions.special.gamma_functions import gamma, lowergamma
from sympy.functions.special.beta_functions import beta
from sympy.functions.special.delta_functions import DiracDelta
from sympy.functions.special.error_functions import Chi
return {KroneckerDelta: r'\delta',
gamma: r'\Gamma',
lowergamma: r'\gamma',
beta: r'\operatorname{B}',
DiracDelta: r'\delta',
Chi: r'\operatorname{Chi}'}
def _print_FunctionClass(self, expr):
for cls in self._special_function_classes:
if issubclass(expr, cls) and expr.__name__ == cls.__name__:
return self._special_function_classes[cls]
return self._hprint_Function(str(expr))
def _print_Lambda(self, expr):
symbols, expr = expr.args
if len(symbols) == 1:
symbols = self._print(symbols[0])
else:
symbols = self._print(tuple(symbols))
args = (symbols, self._print(expr))
tex = r"\left( %s \mapsto %s \right)" % (symbols, self._print(expr))
return tex
def _hprint_variadic_function(self, expr, exp=None):
args = sorted(expr.args, key=default_sort_key)
texargs = [r"%s" % self._print(symbol) for symbol in args]
tex = r"\%s\left(%s\right)" % (self._print((str(expr.func)).lower()), ", ".join(texargs))
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
_print_Min = _print_Max = _hprint_variadic_function
def _print_floor(self, expr, exp=None):
tex = r"\lfloor{%s}\rfloor" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_ceiling(self, expr, exp=None):
tex = r"\lceil{%s}\rceil" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_log(self, expr, exp=None):
if not self._settings["ln_notation"]:
tex = r"\log{\left (%s \right )}" % self._print(expr.args[0])
else:
tex = r"\ln{\left (%s \right )}" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_Abs(self, expr, exp=None):
tex = r"\left|{%s}\right|" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
_print_Determinant = _print_Abs
def _print_re(self, expr, exp=None):
tex = r"\Re{%s}" % self.parenthesize(expr.args[0], PRECEDENCE['Atom'])
return self._do_exponent(tex, exp)
def _print_im(self, expr, exp=None):
tex = r"\Im{%s}" % self.parenthesize(expr.args[0], PRECEDENCE['Func'])
return self._do_exponent(tex, exp)
def _print_Not(self, e):
from sympy import Equivalent, Implies
if isinstance(e.args[0], Equivalent):
return self._print_Equivalent(e.args[0], r"\not\Leftrightarrow")
if isinstance(e.args[0], Implies):
return self._print_Implies(e.args[0], r"\not\Rightarrow")
if (e.args[0].is_Boolean):
return r"\neg (%s)" % self._print(e.args[0])
else:
return r"\neg %s" % self._print(e.args[0])
def _print_LogOp(self, args, char):
arg = args[0]
if arg.is_Boolean and not arg.is_Not:
tex = r"\left(%s\right)" % self._print(arg)
else:
tex = r"%s" % self._print(arg)
for arg in args[1:]:
if arg.is_Boolean and not arg.is_Not:
tex += r" %s \left(%s\right)" % (char, self._print(arg))
else:
tex += r" %s %s" % (char, self._print(arg))
return tex
def _print_And(self, e):
args = sorted(e.args, key=default_sort_key)
return self._print_LogOp(args, r"\wedge")
def _print_Or(self, e):
args = sorted(e.args, key=default_sort_key)
return self._print_LogOp(args, r"\vee")
def _print_Xor(self, e):
args = sorted(e.args, key=default_sort_key)
return self._print_LogOp(args, r"\veebar")
def _print_Implies(self, e, altchar=None):
return self._print_LogOp(e.args, altchar or r"\Rightarrow")
def _print_Equivalent(self, e, altchar=None):
args = sorted(e.args, key=default_sort_key)
return self._print_LogOp(args, altchar or r"\Leftrightarrow")
def _print_conjugate(self, expr, exp=None):
tex = r"\overline{%s}" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_polar_lift(self, expr, exp=None):
func = r"\operatorname{polar\_lift}"
arg = r"{\left (%s \right )}" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}%s" % (func, exp, arg)
else:
return r"%s%s" % (func, arg)
def _print_ExpBase(self, expr, exp=None):
# TODO should exp_polar be printed differently?
# what about exp_polar(0), exp_polar(1)?
tex = r"e^{%s}" % self._print(expr.args[0])
return self._do_exponent(tex, exp)
def _print_elliptic_k(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"K^{%s}%s" % (exp, tex)
else:
return r"K%s" % tex
def _print_elliptic_f(self, expr, exp=None):
tex = r"\left(%s\middle| %s\right)" % \
(self._print(expr.args[0]), self._print(expr.args[1]))
if exp is not None:
return r"F^{%s}%s" % (exp, tex)
else:
return r"F%s" % tex
def _print_elliptic_e(self, expr, exp=None):
if len(expr.args) == 2:
tex = r"\left(%s\middle| %s\right)" % \
(self._print(expr.args[0]), self._print(expr.args[1]))
else:
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"E^{%s}%s" % (exp, tex)
else:
return r"E%s" % tex
def _print_elliptic_pi(self, expr, exp=None):
if len(expr.args) == 3:
tex = r"\left(%s; %s\middle| %s\right)" % \
(self._print(expr.args[0]), self._print(expr.args[1]), \
self._print(expr.args[2]))
else:
tex = r"\left(%s\middle| %s\right)" % \
(self._print(expr.args[0]), self._print(expr.args[1]))
if exp is not None:
return r"\Pi^{%s}%s" % (exp, tex)
else:
return r"\Pi%s" % tex
def _print_beta(self, expr, exp=None):
tex = r"\left(%s, %s\right)" % (self._print(expr.args[0]),
self._print(expr.args[1]))
if exp is not None:
return r"\operatorname{B}^{%s}%s" % (exp, tex)
else:
return r"\operatorname{B}%s" % tex
def _print_uppergamma(self, expr, exp=None):
tex = r"\left(%s, %s\right)" % (self._print(expr.args[0]),
self._print(expr.args[1]))
if exp is not None:
return r"\Gamma^{%s}%s" % (exp, tex)
else:
return r"\Gamma%s" % tex
def _print_lowergamma(self, expr, exp=None):
tex = r"\left(%s, %s\right)" % (self._print(expr.args[0]),
self._print(expr.args[1]))
if exp is not None:
return r"\gamma^{%s}%s" % (exp, tex)
else:
return r"\gamma%s" % tex
def _hprint_one_arg_func(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}%s" % (self._print(expr.func), exp, tex)
else:
return r"%s%s" % (self._print(expr.func), tex)
_print_gamma = _hprint_one_arg_func
def _print_Chi(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"\operatorname{Chi}^{%s}%s" % (exp, tex)
else:
return r"\operatorname{Chi}%s" % tex
def _print_expint(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[1])
nu = self._print(expr.args[0])
if exp is not None:
return r"\operatorname{E}_{%s}^{%s}%s" % (nu, exp, tex)
else:
return r"\operatorname{E}_{%s}%s" % (nu, tex)
def _print_fresnels(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"S^{%s}%s" % (exp, tex)
else:
return r"S%s" % tex
def _print_fresnelc(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"C^{%s}%s" % (exp, tex)
else:
return r"C%s" % tex
def _print_subfactorial(self, expr, exp=None):
tex = r"!%s" % self.parenthesize(expr.args[0], PRECEDENCE["Func"])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_factorial(self, expr, exp=None):
tex = r"%s!" % self.parenthesize(expr.args[0], PRECEDENCE["Func"])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_factorial2(self, expr, exp=None):
tex = r"%s!!" % self.parenthesize(expr.args[0], PRECEDENCE["Func"])
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_binomial(self, expr, exp=None):
tex = r"{\binom{%s}{%s}}" % (self._print(expr.args[0]),
self._print(expr.args[1]))
if exp is not None:
return r"%s^{%s}" % (tex, exp)
else:
return tex
def _print_RisingFactorial(self, expr, exp=None):
n, k = expr.args
base = r"%s" % self.parenthesize(n, PRECEDENCE['Func'])
tex = r"{%s}^{\left(%s\right)}" % (base, self._print(k))
return self._do_exponent(tex, exp)
def _print_FallingFactorial(self, expr, exp=None):
n, k = expr.args
sub = r"%s" % self.parenthesize(k, PRECEDENCE['Func'])
tex = r"{\left(%s\right)}_{%s}" % (self._print(n), sub)
return self._do_exponent(tex, exp)
def _hprint_BesselBase(self, expr, exp, sym):
tex = r"%s" % (sym)
need_exp = False
if exp is not None:
if tex.find('^') == -1:
tex = r"%s^{%s}" % (tex, self._print(exp))
else:
need_exp = True
tex = r"%s_{%s}\left(%s\right)" % (tex, self._print(expr.order),
self._print(expr.argument))
if need_exp:
tex = self._do_exponent(tex, exp)
return tex
def _hprint_vec(self, vec):
if len(vec) == 0:
return ""
s = ""
for i in vec[:-1]:
s += "%s, " % self._print(i)
s += self._print(vec[-1])
return s
def _print_besselj(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'J')
def _print_besseli(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'I')
def _print_besselk(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'K')
def _print_bessely(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'Y')
def _print_yn(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'y')
def _print_jn(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'j')
def _print_hankel1(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'H^{(1)}')
def _print_hankel2(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'H^{(2)}')
def _print_hn1(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'h^{(1)}')
def _print_hn2(self, expr, exp=None):
return self._hprint_BesselBase(expr, exp, 'h^{(2)}')
def _hprint_airy(self, expr, exp=None, notation=""):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"%s^{%s}%s" % (notation, exp, tex)
else:
return r"%s%s" % (notation, tex)
def _hprint_airy_prime(self, expr, exp=None, notation=""):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"{%s^\prime}^{%s}%s" % (notation, exp, tex)
else:
return r"%s^\prime%s" % (notation, tex)
def _print_airyai(self, expr, exp=None):
return self._hprint_airy(expr, exp, 'Ai')
def _print_airybi(self, expr, exp=None):
return self._hprint_airy(expr, exp, 'Bi')
def _print_airyaiprime(self, expr, exp=None):
return self._hprint_airy_prime(expr, exp, 'Ai')
def _print_airybiprime(self, expr, exp=None):
return self._hprint_airy_prime(expr, exp, 'Bi')
def _print_hyper(self, expr, exp=None):
tex = r"{{}_{%s}F_{%s}\left(\begin{matrix} %s \\ %s \end{matrix}" \
r"\middle| {%s} \right)}" % \
(self._print(len(expr.ap)), self._print(len(expr.bq)),
self._hprint_vec(expr.ap), self._hprint_vec(expr.bq),
self._print(expr.argument))
if exp is not None:
tex = r"{%s}^{%s}" % (tex, self._print(exp))
return tex
def _print_meijerg(self, expr, exp=None):
tex = r"{G_{%s, %s}^{%s, %s}\left(\begin{matrix} %s & %s \\" \
r"%s & %s \end{matrix} \middle| {%s} \right)}" % \
(self._print(len(expr.ap)), self._print(len(expr.bq)),
self._print(len(expr.bm)), self._print(len(expr.an)),
self._hprint_vec(expr.an), self._hprint_vec(expr.aother),
self._hprint_vec(expr.bm), self._hprint_vec(expr.bother),
self._print(expr.argument))
if exp is not None:
tex = r"{%s}^{%s}" % (tex, self._print(exp))
return tex
def _print_dirichlet_eta(self, expr, exp=None):
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"\eta^{%s}%s" % (self._print(exp), tex)
return r"\eta%s" % tex
def _print_zeta(self, expr, exp=None):
if len(expr.args) == 2:
tex = r"\left(%s, %s\right)" % tuple(map(self._print, expr.args))
else:
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"\zeta^{%s}%s" % (self._print(exp), tex)
return r"\zeta%s" % tex
def _print_lerchphi(self, expr, exp=None):
tex = r"\left(%s, %s, %s\right)" % tuple(map(self._print, expr.args))
if exp is None:
return r"\Phi%s" % tex
return r"\Phi^{%s}%s" % (self._print(exp), tex)
def _print_polylog(self, expr, exp=None):
s, z = map(self._print, expr.args)
tex = r"\left(%s\right)" % z
if exp is None:
return r"\operatorname{Li}_{%s}%s" % (s, tex)
return r"\operatorname{Li}_{%s}^{%s}%s" % (s, self._print(exp), tex)
def _print_jacobi(self, expr, exp=None):
n, a, b, x = map(self._print, expr.args)
tex = r"P_{%s}^{\left(%s,%s\right)}\left(%s\right)" % (n, a, b, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_gegenbauer(self, expr, exp=None):
n, a, x = map(self._print, expr.args)
tex = r"C_{%s}^{\left(%s\right)}\left(%s\right)" % (n, a, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_chebyshevt(self, expr, exp=None):
n, x = map(self._print, expr.args)
tex = r"T_{%s}\left(%s\right)" % (n, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_chebyshevu(self, expr, exp=None):
n, x = map(self._print, expr.args)
tex = r"U_{%s}\left(%s\right)" % (n, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_legendre(self, expr, exp=None):
n, x = map(self._print, expr.args)
tex = r"P_{%s}\left(%s\right)" % (n, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_assoc_legendre(self, expr, exp=None):
n, a, x = map(self._print, expr.args)
tex = r"P_{%s}^{\left(%s\right)}\left(%s\right)" % (n, a, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_hermite(self, expr, exp=None):
n, x = map(self._print, expr.args)
tex = r"H_{%s}\left(%s\right)" % (n, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_laguerre(self, expr, exp=None):
n, x = map(self._print, expr.args)
tex = r"L_{%s}\left(%s\right)" % (n, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_assoc_laguerre(self, expr, exp=None):
n, a, x = map(self._print, expr.args)
tex = r"L_{%s}^{\left(%s\right)}\left(%s\right)" % (n, a, x)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_Ynm(self, expr, exp=None):
n, m, theta, phi = map(self._print, expr.args)
tex = r"Y_{%s}^{%s}\left(%s,%s\right)" % (n, m, theta, phi)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_Znm(self, expr, exp=None):
n, m, theta, phi = map(self._print, expr.args)
tex = r"Z_{%s}^{%s}\left(%s,%s\right)" % (n, m, theta, phi)
if exp is not None:
tex = r"\left(" + tex + r"\right)^{%s}" % (self._print(exp))
return tex
def _print_Rational(self, expr):
if expr.q != 1:
sign = ""
p = expr.p
if expr.p < 0:
sign = "- "
p = -p
if self._settings['fold_short_frac']:
return r"%s%d / %d" % (sign, p, expr.q)
return r"%s\frac{%d}{%d}" % (sign, p, expr.q)
else:
return self._print(expr.p)
def _print_Order(self, expr):
s = self._print(expr.expr)
if expr.point and any(p != S.Zero for p in expr.point) or \
len(expr.variables) > 1:
s += '; '
if len(expr.variables) > 1:
s += self._print(expr.variables)
elif len(expr.variables):
s += self._print(expr.variables[0])
s += r'\rightarrow '
if len(expr.point) > 1:
s += self._print(expr.point)
else:
s += self._print(expr.point[0])
return r"O\left(%s\right)" % s
def _print_Symbol(self, expr):
if expr in self._settings['symbol_names']:
return self._settings['symbol_names'][expr]
return self._deal_with_super_sub(expr.name) if \
'\\' not in expr.name else expr.name
_print_RandomSymbol = _print_Symbol
_print_MatrixSymbol = _print_Symbol
def _deal_with_super_sub(self, string):
if '{' in string:
return string
name, supers, subs = split_super_sub(string)
name = translate(name)
supers = [translate(sup) for sup in supers]
subs = [translate(sub) for sub in subs]
# glue all items together:
if len(supers) > 0:
name += "^{%s}" % " ".join(supers)
if len(subs) > 0:
name += "_{%s}" % " ".join(subs)
return name
def _print_Relational(self, expr):
if self._settings['itex']:
gt = r"\gt"
lt = r"\lt"
else:
gt = ">"
lt = "<"
charmap = {
"==": "=",
">": gt,
"<": lt,
">=": r"\geq",
"<=": r"\leq",
"!=": r"\neq",
}
return "%s %s %s" % (self._print(expr.lhs),
charmap[expr.rel_op], self._print(expr.rhs))
def _print_Piecewise(self, expr):
ecpairs = [r"%s & \text{for}\: %s" % (self._print(e), self._print(c))
for e, c in expr.args[:-1]]
if expr.args[-1].cond == true:
ecpairs.append(r"%s & \text{otherwise}" %
self._print(expr.args[-1].expr))
else:
ecpairs.append(r"%s & \text{for}\: %s" %
(self._print(expr.args[-1].expr),
self._print(expr.args[-1].cond)))
tex = r"\begin{cases} %s \end{cases}"
return tex % r" \\".join(ecpairs)
def _print_MatrixBase(self, expr):
lines = []
for line in range(expr.rows): # horrible, should be 'rows'
lines.append(" & ".join([ self._print(i) for i in expr[line, :] ]))
mat_str = self._settings['mat_str']
if mat_str is None:
if self._settings['mode'] == 'inline':
mat_str = 'smallmatrix'
else:
if (expr.cols <= 10) is True:
mat_str = 'matrix'
else:
mat_str = 'array'
out_str = r'\begin{%MATSTR%}%s\end{%MATSTR%}'
out_str = out_str.replace('%MATSTR%', mat_str)
if mat_str == 'array':
out_str = out_str.replace('%s', '{' + 'c'*expr.cols + '}%s')
if self._settings['mat_delim']:
left_delim = self._settings['mat_delim']
right_delim = self._delim_dict[left_delim]
out_str = r'\left' + left_delim + out_str + \
r'\right' + right_delim
return out_str % r"\\".join(lines)
_print_ImmutableMatrix = _print_ImmutableDenseMatrix \
= _print_Matrix \
= _print_MatrixBase
def _print_MatrixElement(self, expr):
return self.parenthesize(expr.parent, PRECEDENCE["Atom"], strict=True) \
+ '_{%s, %s}' % (
self._print(expr.i),
self._print(expr.j)
)
def _print_MatrixSlice(self, expr):
def latexslice(x):
x = list(x)
if x[2] == 1:
del x[2]
if x[1] == x[0] + 1:
del x[1]
if x[0] == 0:
x[0] = ''
return ':'.join(map(self._print, x))
return (self._print(expr.parent) + r'\left[' +
latexslice(expr.rowslice) + ', ' +
latexslice(expr.colslice) + r'\right]')
def _print_BlockMatrix(self, expr):
return self._print(expr.blocks)
def _print_Transpose(self, expr):
mat = expr.arg
from sympy.matrices import MatrixSymbol
if not isinstance(mat, MatrixSymbol):
return r"\left(%s\right)^T" % self._print(mat)
else:
return "%s^T" % self._print(mat)
def _print_Trace(self, expr):
mat = expr.arg
return r"\mathrm{tr}\left (%s \right )" % self._print(mat)
def _print_Adjoint(self, expr):
mat = expr.arg
from sympy.matrices import MatrixSymbol
if not isinstance(mat, MatrixSymbol):
return r"\left(%s\right)^\dagger" % self._print(mat)
else:
return r"%s^\dagger" % self._print(mat)
def _print_MatMul(self, expr):
from sympy import Add, MatAdd, HadamardProduct, MatMul, Mul
parens = lambda x: self.parenthesize(x, precedence_traditional(expr), False)
args = expr.args
if isinstance(args[0], Mul):
args = args[0].as_ordered_factors() + list(args[1:])
else:
args = list(args)
if isinstance(expr, MatMul) and _coeff_isneg(expr):
if args[0] == -1:
args = args[1:]
else:
args[0] = -args[0]
return '- ' + ' '.join(map(parens, args))
else:
return ' '.join(map(parens, args))
def _print_Mod(self, expr, exp=None):
if exp is not None:
return r'\left(%s\bmod{%s}\right)^{%s}' % (self.parenthesize(expr.args[0],
PRECEDENCE['Mul'], strict=True), self._print(expr.args[1]), self._print(exp))
return r'%s\bmod{%s}' % (self.parenthesize(expr.args[0],
PRECEDENCE['Mul'], strict=True), self._print(expr.args[1]))
def _print_HadamardProduct(self, expr):
from sympy import Add, MatAdd, MatMul
def parens(x):
if isinstance(x, (Add, MatAdd, MatMul)):
return r"\left(%s\right)" % self._print(x)
return self._print(x)
return r' \circ '.join(map(parens, expr.args))
def _print_KroneckerProduct(self, expr):
from sympy import Add, MatAdd, MatMul
def parens(x):
if isinstance(x, (Add, MatAdd, MatMul)):
return r"\left(%s\right)" % self._print(x)
return self._print(x)
return r' \otimes '.join(map(parens, expr.args))
def _print_MatPow(self, expr):
base, exp = expr.base, expr.exp
from sympy.matrices import MatrixSymbol
if not isinstance(base, MatrixSymbol):
return r"\left(%s\right)^{%s}" % (self._print(base), self._print(exp))
else:
return "%s^{%s}" % (self._print(base), self._print(exp))
def _print_ZeroMatrix(self, Z):
return r"\mathbb{0}"
def _print_Identity(self, I):
return r"\mathbb{I}"
def _print_NDimArray(self, expr):
if expr.rank() == 0:
return self._print(expr[()])
mat_str = self._settings['mat_str']
if mat_str is None:
if self._settings['mode'] == 'inline':
mat_str = 'smallmatrix'
else:
if (expr.rank() == 0) or (expr.shape[-1] <= 10):
mat_str = 'matrix'
else:
mat_str = 'array'
block_str = r'\begin{%MATSTR%}%s\end{%MATSTR%}'
block_str = block_str.replace('%MATSTR%', mat_str)
if self._settings['mat_delim']:
left_delim = self._settings['mat_delim']
right_delim = self._delim_dict[left_delim]
block_str = r'\left' + left_delim + block_str + \
r'\right' + right_delim
if expr.rank() == 0:
return block_str % ""
level_str = [[]] + [[] for i in range(expr.rank())]
shape_ranges = [list(range(i)) for i in expr.shape]
for outer_i in itertools.product(*shape_ranges):
level_str[-1].append(self._print(expr[outer_i]))
even = True
for back_outer_i in range(expr.rank()-1, -1, -1):
if len(level_str[back_outer_i+1]) < expr.shape[back_outer_i]:
break
if even:
level_str[back_outer_i].append(r" & ".join(level_str[back_outer_i+1]))
else:
level_str[back_outer_i].append(block_str % (r"\\".join(level_str[back_outer_i+1])))
if len(level_str[back_outer_i+1]) == 1:
level_str[back_outer_i][-1] = r"\left[" + level_str[back_outer_i][-1] + r"\right]"
even = not even
level_str[back_outer_i+1] = []
out_str = level_str[0][0]
if expr.rank() % 2 == 1:
out_str = block_str % out_str
return out_str
_print_ImmutableDenseNDimArray = _print_NDimArray
_print_ImmutableSparseNDimArray = _print_NDimArray
_print_MutableDenseNDimArray = _print_NDimArray
_print_MutableSparseNDimArray = _print_NDimArray
def _printer_tensor_indices(self, name, indices, index_map={}):
out_str = self._print(name)
last_valence = None
prev_map = None
for index in indices:
new_valence = index.is_up
if ((index in index_map) or prev_map) and last_valence == new_valence:
out_str += ","
if last_valence != new_valence:
if last_valence is not None:
out_str += "}"
if index.is_up:
out_str += "{}^{"
else:
out_str += "{}_{"
out_str += self._print(index.args[0])
if index in index_map:
out_str += "="
out_str += self._print(index_map[index])
prev_map = True
else:
prev_map = False
last_valence = new_valence
if last_valence is not None:
out_str += "}"
return out_str
def _print_Tensor(self, expr):
name = expr.args[0].args[0]
indices = expr.get_indices()
return self._printer_tensor_indices(name, indices)
def _print_TensorElement(self, expr):
name = expr.expr.args[0].args[0]
indices = expr.expr.get_indices()
index_map = expr.index_map
return self._printer_tensor_indices(name, indices, index_map)
def _print_TensMul(self, expr):
# prints expressions like "A(a)", "3*A(a)", "(1+x)*A(a)"
sign, args = expr._get_args_for_traditional_printer()
return sign + "".join(
[self.parenthesize(arg, precedence(expr)) for arg in args]
)
def _print_TensAdd(self, expr):
a = []
args = expr.args
for x in args:
a.append(self.parenthesize(x, precedence(expr)))
a.sort()
s = ' + '.join(a)
s = s.replace('+ -', '- ')
return s
def _print_TensorIndex(self, expr):
return "{}%s{%s}" % (
"^" if expr.is_up else "_",
self._print(expr.args[0])
)
return self._print(expr.args[0])
def _print_tuple(self, expr):
return r"\left ( %s\right )" % \
r", \quad ".join([ self._print(i) for i in expr ])
def _print_TensorProduct(self, expr):
elements = [self._print(a) for a in expr.args]
return r' \otimes '.join(elements)
def _print_WedgeProduct(self, expr):
elements = [self._print(a) for a in expr.args]
return r' \wedge '.join(elements)
def _print_Tuple(self, expr):
return self._print_tuple(expr)
def _print_list(self, expr):
return r"\left [ %s\right ]" % \
r", \quad ".join([ self._print(i) for i in expr ])
def _print_dict(self, d):
keys = sorted(d.keys(), key=default_sort_key)
items = []
for key in keys:
val = d[key]
items.append("%s : %s" % (self._print(key), self._print(val)))
return r"\left \{ %s\right \}" % r", \quad ".join(items)
def _print_Dict(self, expr):
return self._print_dict(expr)
def _print_DiracDelta(self, expr, exp=None):
if len(expr.args) == 1 or expr.args[1] == 0:
tex = r"\delta\left(%s\right)" % self._print(expr.args[0])
else:
tex = r"\delta^{\left( %s \right)}\left( %s \right)" % (
self._print(expr.args[1]), self._print(expr.args[0]))
if exp:
tex = r"\left(%s\right)^{%s}" % (tex, exp)
return tex
def _print_SingularityFunction(self, expr):
shift = self._print(expr.args[0] - expr.args[1])
power = self._print(expr.args[2])
tex = r"{\langle %s \rangle}^{%s}" % (shift, power)
return tex
def _print_Heaviside(self, expr, exp=None):
tex = r"\theta\left(%s\right)" % self._print(expr.args[0])
if exp:
tex = r"\left(%s\right)^{%s}" % (tex, exp)
return tex
def _print_KroneckerDelta(self, expr, exp=None):
i = self._print(expr.args[0])
j = self._print(expr.args[1])
if expr.args[0].is_Atom and expr.args[1].is_Atom:
tex = r'\delta_{%s %s}' % (i, j)
else:
tex = r'\delta_{%s, %s}' % (i, j)
if exp:
tex = r'\left(%s\right)^{%s}' % (tex, exp)
return tex
def _print_LeviCivita(self, expr, exp=None):
indices = map(self._print, expr.args)
if all(x.is_Atom for x in expr.args):
tex = r'\varepsilon_{%s}' % " ".join(indices)
else:
tex = r'\varepsilon_{%s}' % ", ".join(indices)
if exp:
tex = r'\left(%s\right)^{%s}' % (tex, exp)
return tex
def _print_ProductSet(self, p):
if len(p.sets) > 1 and not has_variety(p.sets):
return self._print(p.sets[0]) + "^{%d}" % len(p.sets)
else:
return r" \times ".join(self._print(set) for set in p.sets)
def _print_RandomDomain(self, d):
if hasattr(d, 'as_boolean'):
return 'Domain: ' + self._print(d.as_boolean())
elif hasattr(d, 'set'):
return ('Domain: ' + self._print(d.symbols) + ' in ' +
self._print(d.set))
elif hasattr(d, 'symbols'):
return 'Domain on ' + self._print(d.symbols)
else:
return self._print(None)
def _print_FiniteSet(self, s):
items = sorted(s.args, key=default_sort_key)
return self._print_set(items)
def _print_set(self, s):
items = sorted(s, key=default_sort_key)
items = ", ".join(map(self._print, items))
return r"\left\{%s\right\}" % items
_print_frozenset = _print_set
def _print_Range(self, s):
dots = r'\ldots'
if s.start.is_infinite:
printset = s.start, dots, s[-1] - s.step, s[-1]
elif s.stop.is_infinite or len(s) > 4:
it = iter(s)
printset = next(it), next(it), dots, s[-1]
else:
printset = tuple(s)
return (r"\left\{"
+ r", ".join(self._print(el) for el in printset)
+ r"\right\}")
def _print_SeqFormula(self, s):
if s.start is S.NegativeInfinity:
stop = s.stop
printset = (r'\ldots', s.coeff(stop - 3), s.coeff(stop - 2),
s.coeff(stop - 1), s.coeff(stop))
elif s.stop is S.Infinity or s.length > 4:
printset = s[:4]
printset.append(r'\ldots')
else:
printset = tuple(s)
return (r"\left["
+ r", ".join(self._print(el) for el in printset)
+ r"\right]")
_print_SeqPer = _print_SeqFormula
_print_SeqAdd = _print_SeqFormula
_print_SeqMul = _print_SeqFormula
def _print_Interval(self, i):
if i.start == i.end:
return r"\left\{%s\right\}" % self._print(i.start)
else:
if i.left_open:
left = '('
else:
left = '['
if i.right_open:
right = ')'
else:
right = ']'
return r"\left%s%s, %s\right%s" % \
(left, self._print(i.start), self._print(i.end), right)
def _print_AccumulationBounds(self, i):
return r"\langle %s, %s\rangle" % \
(self._print(i.min), self._print(i.max))
def _print_Union(self, u):
return r" \cup ".join([self._print(i) for i in u.args])
def _print_Complement(self, u):
return r" \setminus ".join([self._print(i) for i in u.args])
def _print_Intersection(self, u):
return r" \cap ".join([self._print(i) for i in u.args])
def _print_SymmetricDifference(self, u):
return r" \triangle ".join([self._print(i) for i in u.args])
def _print_EmptySet(self, e):
return r"\emptyset"
def _print_Naturals(self, n):
return r"\mathbb{N}"
def _print_Naturals0(self, n):
return r"\mathbb{N}_0"
def _print_Integers(self, i):
return r"\mathbb{Z}"
def _print_Reals(self, i):
return r"\mathbb{R}"
def _print_Complexes(self, i):
return r"\mathbb{C}"
def _print_ImageSet(self, s):
sets = s.args[1:]
varsets = [r"%s \in %s" % (self._print(var), self._print(setv))
for var, setv in zip(s.lamda.variables, sets)]
return r"\left\{%s\; |\; %s\right\}" % (
self._print(s.lamda.expr),
', '.join(varsets))
def _print_ConditionSet(self, s):
vars_print = ', '.join([self._print(var) for var in Tuple(s.sym)])
if s.base_set is S.UniversalSet:
return r"\left\{%s \mid %s \right\}" % (
vars_print,
self._print(s.condition.as_expr()))
return r"\left\{%s \mid %s \in %s \wedge %s \right\}" % (
vars_print,
vars_print,
self._print(s.base_set),
self._print(s.condition.as_expr()))
def _print_ComplexRegion(self, s):
vars_print = ', '.join([self._print(var) for var in s.variables])
return r"\left\{%s\; |\; %s \in %s \right\}" % (
self._print(s.expr),
vars_print,
self._print(s.sets))
def _print_Contains(self, e):
return r"%s \in %s" % tuple(self._print(a) for a in e.args)
def _print_FourierSeries(self, s):
return self._print_Add(s.truncate()) + self._print(r' + \ldots')
def _print_FormalPowerSeries(self, s):
return self._print_Add(s.infinite)
def _print_FiniteField(self, expr):
return r"\mathbb{F}_{%s}" % expr.mod
def _print_IntegerRing(self, expr):
return r"\mathbb{Z}"
def _print_RationalField(self, expr):
return r"\mathbb{Q}"
def _print_RealField(self, expr):
return r"\mathbb{R}"
def _print_ComplexField(self, expr):
return r"\mathbb{C}"
def _print_PolynomialRing(self, expr):
domain = self._print(expr.domain)
symbols = ", ".join(map(self._print, expr.symbols))
return r"%s\left[%s\right]" % (domain, symbols)
def _print_FractionField(self, expr):
domain = self._print(expr.domain)
symbols = ", ".join(map(self._print, expr.symbols))
return r"%s\left(%s\right)" % (domain, symbols)
def _print_PolynomialRingBase(self, expr):
domain = self._print(expr.domain)
symbols = ", ".join(map(self._print, expr.symbols))
inv = ""
if not expr.is_Poly:
inv = r"S_<^{-1}"
return r"%s%s\left[%s\right]" % (inv, domain, symbols)
def _print_Poly(self, poly):
cls = poly.__class__.__name__
terms = []
for monom, coeff in poly.terms():
s_monom = ''
for i, exp in enumerate(monom):
if exp > 0:
if exp == 1:
s_monom += self._print(poly.gens[i])
else:
s_monom += self._print(pow(poly.gens[i], exp))
if coeff.is_Add:
if s_monom:
s_coeff = r"\left(%s\right)" % self._print(coeff)
else:
s_coeff = self._print(coeff)
else:
if s_monom:
if coeff is S.One:
terms.extend(['+', s_monom])
continue
if coeff is S.NegativeOne:
terms.extend(['-', s_monom])
continue
s_coeff = self._print(coeff)
if not s_monom:
s_term = s_coeff
else:
s_term = s_coeff + " " + s_monom
if s_term.startswith('-'):
terms.extend(['-', s_term[1:]])
else:
terms.extend(['+', s_term])
if terms[0] in ['-', '+']:
modifier = terms.pop(0)
if modifier == '-':
terms[0] = '-' + terms[0]
expr = ' '.join(terms)
gens = list(map(self._print, poly.gens))
domain = "domain=%s" % self._print(poly.get_domain())
args = ", ".join([expr] + gens + [domain])
if cls in accepted_latex_functions:
tex = r"\%s {\left (%s \right )}" % (cls, args)
else:
tex = r"\operatorname{%s}{\left( %s \right)}" % (cls, args)
return tex
def _print_ComplexRootOf(self, root):
cls = root.__class__.__name__
if cls == "ComplexRootOf":
cls = "CRootOf"
expr = self._print(root.expr)
index = root.index
if cls in accepted_latex_functions:
return r"\%s {\left(%s, %d\right)}" % (cls, expr, index)
else:
return r"\operatorname{%s} {\left(%s, %d\right)}" % (cls, expr, index)
def _print_RootSum(self, expr):
cls = expr.__class__.__name__
args = [self._print(expr.expr)]
if expr.fun is not S.IdentityFunction:
args.append(self._print(expr.fun))
if cls in accepted_latex_functions:
return r"\%s {\left(%s\right)}" % (cls, ", ".join(args))
else:
return r"\operatorname{%s} {\left(%s\right)}" % (cls, ", ".join(args))
def _print_PolyElement(self, poly):
mul_symbol = self._settings['mul_symbol_latex']
return poly.str(self, PRECEDENCE, "{%s}^{%d}", mul_symbol)
def _print_FracElement(self, frac):
if frac.denom == 1:
return self._print(frac.numer)
else:
numer = self._print(frac.numer)
denom = self._print(frac.denom)
return r"\frac{%s}{%s}" % (numer, denom)
def _print_euler(self, expr, exp=None):
m, x = (expr.args[0], None) if len(expr.args) == 1 else expr.args
tex = r"E_{%s}" % self._print(m)
if exp is not None:
tex = r"%s^{%s}" % (tex, self._print(exp))
if x is not None:
tex = r"%s\left(%s\right)" % (tex, self._print(x))
return tex
def _print_catalan(self, expr, exp=None):
tex = r"C_{%s}" % self._print(expr.args[0])
if exp is not None:
tex = r"%s^{%s}" % (tex, self._print(exp))
return tex
def _print_MellinTransform(self, expr):
return r"\mathcal{M}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_InverseMellinTransform(self, expr):
return r"\mathcal{M}^{-1}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_LaplaceTransform(self, expr):
return r"\mathcal{L}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_InverseLaplaceTransform(self, expr):
return r"\mathcal{L}^{-1}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_FourierTransform(self, expr):
return r"\mathcal{F}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_InverseFourierTransform(self, expr):
return r"\mathcal{F}^{-1}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_SineTransform(self, expr):
return r"\mathcal{SIN}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_InverseSineTransform(self, expr):
return r"\mathcal{SIN}^{-1}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_CosineTransform(self, expr):
return r"\mathcal{COS}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_InverseCosineTransform(self, expr):
return r"\mathcal{COS}^{-1}_{%s}\left[%s\right]\left(%s\right)" % (self._print(expr.args[1]), self._print(expr.args[0]), self._print(expr.args[2]))
def _print_DMP(self, p):
try:
if p.ring is not None:
# TODO incorporate order
return self._print(p.ring.to_sympy(p))
except SympifyError:
pass
return self._print(repr(p))
def _print_DMF(self, p):
return self._print_DMP(p)
def _print_Object(self, object):
return self._print(Symbol(object.name))
def _print_Morphism(self, morphism):
domain = self._print(morphism.domain)
codomain = self._print(morphism.codomain)
return "%s\\rightarrow %s" % (domain, codomain)
def _print_NamedMorphism(self, morphism):
pretty_name = self._print(Symbol(morphism.name))
pretty_morphism = self._print_Morphism(morphism)
return "%s:%s" % (pretty_name, pretty_morphism)
def _print_IdentityMorphism(self, morphism):
from sympy.categories import NamedMorphism
return self._print_NamedMorphism(NamedMorphism(
morphism.domain, morphism.codomain, "id"))
def _print_CompositeMorphism(self, morphism):
# All components of the morphism have names and it is thus
# possible to build the name of the composite.
component_names_list = [self._print(Symbol(component.name)) for
component in morphism.components]
component_names_list.reverse()
component_names = "\\circ ".join(component_names_list) + ":"
pretty_morphism = self._print_Morphism(morphism)
return component_names + pretty_morphism
def _print_Category(self, morphism):
return "\\mathbf{%s}" % self._print(Symbol(morphism.name))
def _print_Diagram(self, diagram):
if not diagram.premises:
# This is an empty diagram.
return self._print(S.EmptySet)
latex_result = self._print(diagram.premises)
if diagram.conclusions:
latex_result += "\\Longrightarrow %s" % \
self._print(diagram.conclusions)
return latex_result
def _print_DiagramGrid(self, grid):
latex_result = "\\begin{array}{%s}\n" % ("c" * grid.width)
for i in range(grid.height):
for j in range(grid.width):
if grid[i, j]:
latex_result += latex(grid[i, j])
latex_result += " "
if j != grid.width - 1:
latex_result += "& "
if i != grid.height - 1:
latex_result += "\\\\"
latex_result += "\n"
latex_result += "\\end{array}\n"
return latex_result
def _print_FreeModule(self, M):
return '{%s}^{%s}' % (self._print(M.ring), self._print(M.rank))
def _print_FreeModuleElement(self, m):
# Print as row vector for convenience, for now.
return r"\left[ %s \right]" % ",".join(
'{' + self._print(x) + '}' for x in m)
def _print_SubModule(self, m):
return r"\left< %s \right>" % ",".join(
'{' + self._print(x) + '}' for x in m.gens)
def _print_ModuleImplementedIdeal(self, m):
return r"\left< %s \right>" % ",".join(
'{' + self._print(x) + '}' for [x] in m._module.gens)
def _print_Quaternion(self, expr):
# TODO: This expression is potentially confusing,
# shall we print it as `Quaternion( ... )`?
s = [self.parenthesize(i, PRECEDENCE["Mul"], strict=True) for i in expr.args]
a = [s[0]] + [i+" "+j for i, j in zip(s[1:], "ijk")]
return " + ".join(a)
def _print_QuotientRing(self, R):
# TODO nicer fractions for few generators...
return r"\frac{%s}{%s}" % (self._print(R.ring), self._print(R.base_ideal))
def _print_QuotientRingElement(self, x):
return r"{%s} + {%s}" % (self._print(x.data), self._print(x.ring.base_ideal))
def _print_QuotientModuleElement(self, m):
return r"{%s} + {%s}" % (self._print(m.data),
self._print(m.module.killed_module))
def _print_QuotientModule(self, M):
# TODO nicer fractions for few generators...
return r"\frac{%s}{%s}" % (self._print(M.base),
self._print(M.killed_module))
def _print_MatrixHomomorphism(self, h):
return r"{%s} : {%s} \to {%s}" % (self._print(h._sympy_matrix()),
self._print(h.domain), self._print(h.codomain))
def _print_BaseScalarField(self, field):
string = field._coord_sys._names[field._index]
return r'\boldsymbol{\mathrm{%s}}' % self._print(Symbol(string))
def _print_BaseVectorField(self, field):
string = field._coord_sys._names[field._index]
return r'\partial_{%s}' % self._print(Symbol(string))
def _print_Differential(self, diff):
field = diff._form_field
if hasattr(field, '_coord_sys'):
string = field._coord_sys._names[field._index]
return r'\mathrm{d}%s' % self._print(Symbol(string))
else:
return 'd(%s)' % self._print(field)
string = self._print(field)
return r'\mathrm{d}\left(%s\right)' % string
def _print_Tr(self, p):
#Todo: Handle indices
contents = self._print(p.args[0])
return r'\mbox{Tr}\left(%s\right)' % (contents)
def _print_totient(self, expr, exp=None):
if exp is not None:
return r'\left(\phi\left(%s\right)\right)^{%s}' % (self._print(expr.args[0]),
self._print(exp))
return r'\phi\left(%s\right)' % self._print(expr.args[0])
def _print_reduced_totient(self, expr, exp=None):
if exp is not None:
return r'\left(\lambda\left(%s\right)\right)^{%s}' % (self._print(expr.args[0]),
self._print(exp))
return r'\lambda\left(%s\right)' % self._print(expr.args[0])
def _print_divisor_sigma(self, expr, exp=None):
if len(expr.args) == 2:
tex = r"_%s\left(%s\right)" % tuple(map(self._print,
(expr.args[1], expr.args[0])))
else:
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"\sigma^{%s}%s" % (self._print(exp), tex)
return r"\sigma%s" % tex
def _print_udivisor_sigma(self, expr, exp=None):
if len(expr.args) == 2:
tex = r"_%s\left(%s\right)" % tuple(map(self._print,
(expr.args[1], expr.args[0])))
else:
tex = r"\left(%s\right)" % self._print(expr.args[0])
if exp is not None:
return r"\sigma^*^{%s}%s" % (self._print(exp), tex)
return r"\sigma^*%s" % tex
def _print_primenu(self, expr, exp=None):
if exp is not None:
return r'\left(\nu\left(%s\right)\right)^{%s}' % (self._print(expr.args[0]),
self._print(exp))
return r'\nu\left(%s\right)' % self._print(expr.args[0])
def _print_primeomega(self, expr, exp=None):
if exp is not None:
return r'\left(\Omega\left(%s\right)\right)^{%s}' % (self._print(expr.args[0]),
self._print(exp))
return r'\Omega\left(%s\right)' % self._print(expr.args[0])
def translate(s):
r'''
Check for a modifier ending the string. If present, convert the
modifier to latex and translate the rest recursively.
Given a description of a Greek letter or other special character,
return the appropriate latex.
Let everything else pass as given.
>>> from sympy.printing.latex import translate
>>> translate('alphahatdotprime')
"{\\dot{\\hat{\\alpha}}}'"
'''
# Process the rest
tex = tex_greek_dictionary.get(s)
if tex:
return tex
elif s.lower() in greek_letters_set:
return "\\" + s.lower()
elif s in other_symbols:
return "\\" + s
else:
# Process modifiers, if any, and recurse
for key in sorted(modifier_dict.keys(), key=lambda k:len(k), reverse=True):
if s.lower().endswith(key) and len(s)>len(key):
return modifier_dict[key](translate(s[:-len(key)]))
return s
def latex(expr, fold_frac_powers=False, fold_func_brackets=False,
fold_short_frac=None, inv_trig_style="abbreviated",
itex=False, ln_notation=False, long_frac_ratio=None,
mat_delim="[", mat_str=None, mode="plain", mul_symbol=None,
order=None, symbol_names=None):
r"""Convert the given expression to LaTeX string representation.
Parameters
==========
fold_frac_powers : boolean, optional
Emit ``^{p/q}`` instead of ``^{\frac{p}{q}}`` for fractional powers.
fold_func_brackets : boolean, optional
Fold function brackets where applicable.
fold_short_frac : boolean, optional
Emit ``p / q`` instead of ``\frac{p}{q}`` when the denominator is
simple enough (at most two terms and no powers). The default value is
``True`` for inline mode, ``False`` otherwise.
inv_trig_style : string, optional
How inverse trig functions should be displayed. Can be one of
``abbreviated``, ``full``, or ``power``. Defaults to ``abbreviated``.
itex : boolean, optional
Specifies if itex-specific syntax is used, including emitting
``$$...$$``.
ln_notation : boolean, optional
If set to ``True``, ``\ln`` is used instead of default ``\log``.
long_frac_ratio : float or None, optional
The allowed ratio of the width of the numerator to the width of the
denominator before the printer breaks off long fractions. If ``None``
(the default value), long fractions are not broken up.
mat_delim : string, optional
The delimiter to wrap around matrices. Can be one of ``[``, ``(``, or
the empty string. Defaults to ``[``.
mat_str : string, optional
Which matrix environment string to emit. ``smallmatrix``, ``matrix``,
``array``, etc. Defaults to ``smallmatrix`` for inline mode, ``matrix``
for matrices of no more than 10 columns, and ``array`` otherwise.
mode: string, optional
Specifies how the generated code will be delimited. ``mode`` can be one
of ``plain``, ``inline``, ``equation`` or ``equation*``. If ``mode``
is set to ``plain``, then the resulting code will not be delimited at
all (this is the default). If ``mode`` is set to ``inline`` then inline
LaTeX ``$...$`` will be used. If ``mode`` is set to ``equation`` or
``equation*``, the resulting code will be enclosed in the ``equation``
or ``equation*`` environment (remember to import ``amsmath`` for
``equation*``), unless the ``itex`` option is set. In the latter case,
the ``$$...$$`` syntax is used.
mul_symbol : string or None, optional
The symbol to use for multiplication. Can be one of ``None``, ``ldot``,
``dot``, or ``times``.
order: string, optional
Any of the supported monomial orderings (currently ``lex``, ``grlex``,
or ``grevlex``), ``old``, and ``none``. This parameter does nothing for
Mul objects. Setting order to ``old`` uses the compatibility ordering
for Add defined in Printer. For very large expressions, set the
``order`` keyword to ``none`` if speed is a concern.
symbol_names : dictionary of strings mapped to symbols, optional
Dictionary of symbols and the custom strings they should be emitted as.
Notes
=====
Not using a print statement for printing, results in double backslashes for
latex commands since that's the way Python escapes backslashes in strings.
>>> from sympy import latex, Rational
>>> from sympy.abc import tau
>>> latex((2*tau)**Rational(7,2))
'8 \\sqrt{2} \\tau^{\\frac{7}{2}}'
>>> print(latex((2*tau)**Rational(7,2)))
8 \sqrt{2} \tau^{\frac{7}{2}}
Examples
========
>>> from sympy import latex, pi, sin, asin, Integral, Matrix, Rational, log
>>> from sympy.abc import x, y, mu, r, tau
Basic usage:
>>> print(latex((2*tau)**Rational(7,2)))
8 \sqrt{2} \tau^{\frac{7}{2}}
``mode`` and ``itex`` options:
>>> print(latex((2*mu)**Rational(7,2), mode='plain'))
8 \sqrt{2} \mu^{\frac{7}{2}}
>>> print(latex((2*tau)**Rational(7,2), mode='inline'))
$8 \sqrt{2} \tau^{7 / 2}$
>>> print(latex((2*mu)**Rational(7,2), mode='equation*'))
\begin{equation*}8 \sqrt{2} \mu^{\frac{7}{2}}\end{equation*}
>>> print(latex((2*mu)**Rational(7,2), mode='equation'))
\begin{equation}8 \sqrt{2} \mu^{\frac{7}{2}}\end{equation}
>>> print(latex((2*mu)**Rational(7,2), mode='equation', itex=True))
$$8 \sqrt{2} \mu^{\frac{7}{2}}$$
>>> print(latex((2*mu)**Rational(7,2), mode='plain'))
8 \sqrt{2} \mu^{\frac{7}{2}}
>>> print(latex((2*tau)**Rational(7,2), mode='inline'))
$8 \sqrt{2} \tau^{7 / 2}$
>>> print(latex((2*mu)**Rational(7,2), mode='equation*'))
\begin{equation*}8 \sqrt{2} \mu^{\frac{7}{2}}\end{equation*}
>>> print(latex((2*mu)**Rational(7,2), mode='equation'))
\begin{equation}8 \sqrt{2} \mu^{\frac{7}{2}}\end{equation}
>>> print(latex((2*mu)**Rational(7,2), mode='equation', itex=True))
$$8 \sqrt{2} \mu^{\frac{7}{2}}$$
Fraction options:
>>> print(latex((2*tau)**Rational(7,2), fold_frac_powers=True))
8 \sqrt{2} \tau^{7/2}
>>> print(latex((2*tau)**sin(Rational(7,2))))
\left(2 \tau\right)^{\sin{\left (\frac{7}{2} \right )}}
>>> print(latex((2*tau)**sin(Rational(7,2)), fold_func_brackets=True))
\left(2 \tau\right)^{\sin {\frac{7}{2}}}
>>> print(latex(3*x**2/y))
\frac{3 x^{2}}{y}
>>> print(latex(3*x**2/y, fold_short_frac=True))
3 x^{2} / y
>>> print(latex(Integral(r, r)/2/pi, long_frac_ratio=2))
\frac{\int r\, dr}{2 \pi}
>>> print(latex(Integral(r, r)/2/pi, long_frac_ratio=0))
\frac{1}{2 \pi} \int r\, dr
Multiplication options:
>>> print(latex((2*tau)**sin(Rational(7,2)), mul_symbol="times"))
\left(2 \times \tau\right)^{\sin{\left (\frac{7}{2} \right )}}
Trig options:
>>> print(latex(asin(Rational(7,2))))
\operatorname{asin}{\left (\frac{7}{2} \right )}
>>> print(latex(asin(Rational(7,2)), inv_trig_style="full"))
\arcsin{\left (\frac{7}{2} \right )}
>>> print(latex(asin(Rational(7,2)), inv_trig_style="power"))
\sin^{-1}{\left (\frac{7}{2} \right )}
Matrix options:
>>> print(latex(Matrix(2, 1, [x, y])))
\left[\begin{matrix}x\\y\end{matrix}\right]
>>> print(latex(Matrix(2, 1, [x, y]), mat_str = "array"))
\left[\begin{array}{c}x\\y\end{array}\right]
>>> print(latex(Matrix(2, 1, [x, y]), mat_delim="("))
\left(\begin{matrix}x\\y\end{matrix}\right)
Custom printing of symbols:
>>> print(latex(x**2, symbol_names={x: 'x_i'}))
x_i^{2}
Logarithms:
>>> print(latex(log(10)))
\log{\left (10 \right )}
>>> print(latex(log(10), ln_notation=True))
\ln{\left (10 \right )}
``latex()`` also supports the builtin container types list, tuple, and
dictionary.
>>> print(latex([2/x, y], mode='inline'))
$\left [ 2 / x, \quad y\right ]$
"""
if symbol_names is None:
symbol_names = {}
settings = {
'fold_frac_powers' : fold_frac_powers,
'fold_func_brackets' : fold_func_brackets,
'fold_short_frac' : fold_short_frac,
'inv_trig_style' : inv_trig_style,
'itex' : itex,
'ln_notation' : ln_notation,
'long_frac_ratio' : long_frac_ratio,
'mat_delim' : mat_delim,
'mat_str' : mat_str,
'mode' : mode,
'mul_symbol' : mul_symbol,
'order' : order,
'symbol_names' : symbol_names,
}
return LatexPrinter(settings).doprint(expr)
def print_latex(expr, **settings):
"""Prints LaTeX representation of the given expression. Takes the same
settings as ``latex()``."""
print(latex(expr, **settings))
|
0cfa9557f093615bba0689ad53412bc53923f6aab1c8a3788ab6328d51e354a1
|
from __future__ import print_function, division
import os
from os.path import join
import tempfile
import shutil
import io
from io import BytesIO
try:
from subprocess import STDOUT, CalledProcessError, check_output
except ImportError:
pass
from sympy.core.compatibility import unicode, u_decode
from sympy.utilities.exceptions import SymPyDeprecationWarning
from sympy.utilities.misc import find_executable
from .latex import latex
from sympy.utilities.decorator import doctest_depends_on
__doctest_requires__ = {('preview',): ['pyglet']}
@doctest_depends_on(exe=('latex', 'dvipng'), modules=('pyglet',),
disable_viewers=('evince', 'gimp', 'superior-dvi-viewer'))
def preview(expr, output='png', viewer=None, euler=True, packages=(),
filename=None, outputbuffer=None, preamble=None, dvioptions=None,
outputTexFile=None, **latex_settings):
r"""
View expression or LaTeX markup in PNG, DVI, PostScript or PDF form.
If the expr argument is an expression, it will be exported to LaTeX and
then compiled using the available TeX distribution. The first argument,
'expr', may also be a LaTeX string. The function will then run the
appropriate viewer for the given output format or use the user defined
one. By default png output is generated.
By default pretty Euler fonts are used for typesetting (they were used to
typeset the well known "Concrete Mathematics" book). For that to work, you
need the 'eulervm.sty' LaTeX style (in Debian/Ubuntu, install the
texlive-fonts-extra package). If you prefer default AMS fonts or your
system lacks 'eulervm' LaTeX package then unset the 'euler' keyword
argument.
To use viewer auto-detection, lets say for 'png' output, issue
>>> from sympy import symbols, preview, Symbol
>>> x, y = symbols("x,y")
>>> preview(x + y, output='png')
This will choose 'pyglet' by default. To select a different one, do
>>> preview(x + y, output='png', viewer='gimp')
The 'png' format is considered special. For all other formats the rules
are slightly different. As an example we will take 'dvi' output format. If
you would run
>>> preview(x + y, output='dvi')
then 'view' will look for available 'dvi' viewers on your system
(predefined in the function, so it will try evince, first, then kdvi and
xdvi). If nothing is found you will need to set the viewer explicitly.
>>> preview(x + y, output='dvi', viewer='superior-dvi-viewer')
This will skip auto-detection and will run user specified
'superior-dvi-viewer'. If 'view' fails to find it on your system it will
gracefully raise an exception.
You may also enter 'file' for the viewer argument. Doing so will cause
this function to return a file object in read-only mode, if 'filename'
is unset. However, if it was set, then 'preview' writes the genereted
file to this filename instead.
There is also support for writing to a BytesIO like object, which needs
to be passed to the 'outputbuffer' argument.
>>> from io import BytesIO
>>> obj = BytesIO()
>>> preview(x + y, output='png', viewer='BytesIO',
... outputbuffer=obj)
The LaTeX preamble can be customized by setting the 'preamble' keyword
argument. This can be used, e.g., to set a different font size, use a
custom documentclass or import certain set of LaTeX packages.
>>> preamble = "\\documentclass[10pt]{article}\n" \
... "\\usepackage{amsmath,amsfonts}\\begin{document}"
>>> preview(x + y, output='png', preamble=preamble)
If the value of 'output' is different from 'dvi' then command line
options can be set ('dvioptions' argument) for the execution of the
'dvi'+output conversion tool. These options have to be in the form of a
list of strings (see subprocess.Popen).
Additional keyword args will be passed to the latex call, e.g., the
symbol_names flag.
>>> phidd = Symbol('phidd')
>>> preview(phidd, symbol_names={phidd:r'\ddot{\varphi}'})
For post-processing the generated TeX File can be written to a file by
passing the desired filename to the 'outputTexFile' keyword
argument. To write the TeX code to a file named
"sample.tex" and run the default png viewer to display the resulting
bitmap, do
>>> preview(x + y, outputTexFile="sample.tex")
"""
special = [ 'pyglet' ]
if viewer is None:
if output == "png":
viewer = "pyglet"
else:
# sorted in order from most pretty to most ugly
# very discussable, but indeed 'gv' looks awful :)
# TODO add candidates for windows to list
candidates = {
"dvi": [ "evince", "okular", "kdvi", "xdvi" ],
"ps": [ "evince", "okular", "gsview", "gv" ],
"pdf": [ "evince", "okular", "kpdf", "acroread", "xpdf", "gv" ],
}
try:
for candidate in candidates[output]:
path = find_executable(candidate)
if path is not None:
viewer = path
break
else:
raise SystemError(
"No viewers found for '%s' output format." % output)
except KeyError:
raise SystemError("Invalid output format: %s" % output)
else:
if viewer == "file":
if filename is None:
SymPyDeprecationWarning(feature="Using viewer=\"file\" without a "
"specified filename", deprecated_since_version="0.7.3",
useinstead="viewer=\"file\" and filename=\"desiredname\"",
issue=7018).warn()
elif viewer == "StringIO":
SymPyDeprecationWarning(feature="The preview() viewer StringIO",
useinstead="BytesIO", deprecated_since_version="0.7.4",
issue=7083).warn()
viewer = "BytesIO"
if outputbuffer is None:
raise ValueError("outputbuffer has to be a BytesIO "
"compatible object if viewer=\"StringIO\"")
elif viewer == "BytesIO":
if outputbuffer is None:
raise ValueError("outputbuffer has to be a BytesIO "
"compatible object if viewer=\"BytesIO\"")
elif viewer not in special and not find_executable(viewer):
raise SystemError("Unrecognized viewer: %s" % viewer)
if preamble is None:
actual_packages = packages + ("amsmath", "amsfonts")
if euler:
actual_packages += ("euler",)
package_includes = "\n" + "\n".join(["\\usepackage{%s}" % p
for p in actual_packages])
preamble = r"""\documentclass[varwidth,12pt]{standalone}
%s
\begin{document}
""" % (package_includes)
else:
if len(packages) > 0:
raise ValueError("The \"packages\" keyword must not be set if a "
"custom LaTeX preamble was specified")
latex_main = preamble + '\n%s\n\n' + r"\end{document}"
if isinstance(expr, str):
latex_string = expr
else:
latex_string = ('$\\displaystyle ' +
latex(expr, mode='plain', **latex_settings) +
'$')
try:
workdir = tempfile.mkdtemp()
with io.open(join(workdir, 'texput.tex'), 'w', encoding='utf-8') as fh:
fh.write(unicode(latex_main) % u_decode(latex_string))
if outputTexFile is not None:
shutil.copyfile(join(workdir, 'texput.tex'), outputTexFile)
if not find_executable('latex'):
raise RuntimeError("latex program is not installed")
try:
# Avoid showing a cmd.exe window when running this
# on Windows
if os.name == 'nt':
creation_flag = 0x08000000 # CREATE_NO_WINDOW
else:
creation_flag = 0 # Default value
check_output(['latex', '-halt-on-error', '-interaction=nonstopmode',
'texput.tex'],
cwd=workdir,
stderr=STDOUT,
creationflags=creation_flag)
except CalledProcessError as e:
raise RuntimeError(
"'latex' exited abnormally with the following output:\n%s" %
e.output)
if output != "dvi":
defaultoptions = {
"ps": [],
"pdf": [],
"png": ["-T", "tight", "-z", "9", "--truecolor"],
"svg": ["--no-fonts"],
}
commandend = {
"ps": ["-o", "texput.ps", "texput.dvi"],
"pdf": ["texput.dvi", "texput.pdf"],
"png": ["-o", "texput.png", "texput.dvi"],
"svg": ["-o", "texput.svg", "texput.dvi"],
}
if output == "svg":
cmd = ["dvisvgm"]
else:
cmd = ["dvi" + output]
if not find_executable(cmd[0]):
raise RuntimeError("%s is not installed" % cmd[0])
try:
if dvioptions is not None:
cmd.extend(dvioptions)
else:
cmd.extend(defaultoptions[output])
cmd.extend(commandend[output])
except KeyError:
raise SystemError("Invalid output format: %s" % output)
try:
# Avoid showing a cmd.exe window when running this
# on Windows
if os.name == 'nt':
creation_flag = 0x08000000 # CREATE_NO_WINDOW
else:
creation_flag = 0 # Default value
check_output(cmd, cwd=workdir, stderr=STDOUT,
creationflags=creation_flag)
except CalledProcessError as e:
raise RuntimeError(
"'%s' exited abnormally with the following output:\n%s" %
(' '.join(cmd), e.output))
src = "texput.%s" % (output)
if viewer == "file":
if filename is None:
buffer = BytesIO()
with open(join(workdir, src), 'rb') as fh:
buffer.write(fh.read())
return buffer
else:
shutil.move(join(workdir,src), filename)
elif viewer == "BytesIO":
with open(join(workdir, src), 'rb') as fh:
outputbuffer.write(fh.read())
elif viewer == "pyglet":
try:
from pyglet import window, image, gl
from pyglet.window import key
except ImportError:
raise ImportError("pyglet is required for preview.\n visit http://www.pyglet.org/")
if output == "png":
from pyglet.image.codecs.png import PNGImageDecoder
img = image.load(join(workdir, src), decoder=PNGImageDecoder())
else:
raise SystemError("pyglet preview works only for 'png' files.")
offset = 25
config = gl.Config(double_buffer=False)
win = window.Window(
width=img.width + 2*offset,
height=img.height + 2*offset,
caption="sympy",
resizable=False,
config=config
)
win.set_vsync(False)
try:
def on_close():
win.has_exit = True
win.on_close = on_close
def on_key_press(symbol, modifiers):
if symbol in [key.Q, key.ESCAPE]:
on_close()
win.on_key_press = on_key_press
def on_expose():
gl.glClearColor(1.0, 1.0, 1.0, 1.0)
gl.glClear(gl.GL_COLOR_BUFFER_BIT)
img.blit(
(win.width - img.width) / 2,
(win.height - img.height) / 2
)
win.on_expose = on_expose
while not win.has_exit:
win.dispatch_events()
win.flip()
except KeyboardInterrupt:
pass
win.close()
else:
try:
# Avoid showing a cmd.exe window when running this
# on Windows
if os.name == 'nt':
creation_flag = 0x08000000 # CREATE_NO_WINDOW
else:
creation_flag = 0 # Default value
check_output([viewer, src], cwd=workdir, stderr=STDOUT,
creationflags=creation_flag)
except CalledProcessError as e:
raise RuntimeError(
"'%s %s' exited abnormally with the following output:\n%s" %
(viewer, src, e.output))
finally:
try:
shutil.rmtree(workdir) # delete directory
except OSError as e:
if e.errno != 2: # code 2 - no such file or directory
raise
|
1b78f90af01940f1607482284d92b6e7ff190f1606edf2c8cd388c069d200f9f
|
"""
A Printer for generating executable code.
The most important function here is srepr that returns a string so that the
relation eval(srepr(expr))=expr holds in an appropriate environment.
"""
from __future__ import print_function, division
from sympy.core.function import AppliedUndef
from .printer import Printer
import mpmath.libmp as mlib
from mpmath.libmp import repr_dps
from sympy.core.compatibility import range
class ReprPrinter(Printer):
printmethod = "_sympyrepr"
_default_settings = {
"order": None
}
def reprify(self, args, sep):
"""
Prints each item in `args` and joins them with `sep`.
"""
return sep.join([self.doprint(item) for item in args])
def emptyPrinter(self, expr):
"""
The fallback printer.
"""
if isinstance(expr, str):
return expr
elif hasattr(expr, "__srepr__"):
return expr.__srepr__()
elif hasattr(expr, "args") and hasattr(expr.args, "__iter__"):
l = []
for o in expr.args:
l.append(self._print(o))
return expr.__class__.__name__ + '(%s)' % ', '.join(l)
elif hasattr(expr, "__module__") and hasattr(expr, "__name__"):
return "<'%s.%s'>" % (expr.__module__, expr.__name__)
else:
return str(expr)
def _print_Add(self, expr, order=None):
args = self._as_ordered_terms(expr, order=order)
nargs = len(args)
args = map(self._print, args)
if nargs > 255: # Issue #10259, Python < 3.7
return "Add(*[%s])" % ", ".join(args)
return "Add(%s)" % ", ".join(args)
def _print_Cycle(self, expr):
return expr.__repr__()
def _print_Function(self, expr):
r = self._print(expr.func)
r += '(%s)' % ', '.join([self._print(a) for a in expr.args])
return r
def _print_FunctionClass(self, expr):
if issubclass(expr, AppliedUndef):
return 'Function(%r)' % (expr.__name__)
else:
return expr.__name__
def _print_Half(self, expr):
return 'Rational(1, 2)'
def _print_RationalConstant(self, expr):
return str(expr)
def _print_AtomicExpr(self, expr):
return str(expr)
def _print_NumberSymbol(self, expr):
return str(expr)
def _print_Integer(self, expr):
return 'Integer(%i)' % expr.p
def _print_Integers(self, expr):
return 'Integers'
def _print_Naturals(self, expr):
return 'Naturals'
def _print_Naturals0(self, expr):
return 'Naturals0'
def _print_Reals(self, expr):
return 'Reals'
def _print_list(self, expr):
return "[%s]" % self.reprify(expr, ", ")
def _print_MatrixBase(self, expr):
# special case for some empty matrices
if (expr.rows == 0) ^ (expr.cols == 0):
return '%s(%s, %s, %s)' % (expr.__class__.__name__,
self._print(expr.rows),
self._print(expr.cols),
self._print([]))
l = []
for i in range(expr.rows):
l.append([])
for j in range(expr.cols):
l[-1].append(expr[i, j])
return '%s(%s)' % (expr.__class__.__name__, self._print(l))
_print_SparseMatrix = \
_print_MutableSparseMatrix = \
_print_ImmutableSparseMatrix = \
_print_Matrix = \
_print_DenseMatrix = \
_print_MutableDenseMatrix = \
_print_ImmutableMatrix = \
_print_ImmutableDenseMatrix = \
_print_MatrixBase
def _print_BooleanTrue(self, expr):
return "true"
def _print_BooleanFalse(self, expr):
return "false"
def _print_NaN(self, expr):
return "nan"
def _print_Mul(self, expr, order=None):
terms = expr.args
if self.order != 'old':
args = expr._new_rawargs(*terms).as_ordered_factors()
else:
args = terms
nargs = len(args)
args = map(self._print, args)
if nargs > 255: # Issue #10259, Python < 3.7
return "Mul(*[%s])" % ", ".join(args)
return "Mul(%s)" % ", ".join(args)
def _print_Rational(self, expr):
return 'Rational(%s, %s)' % (self._print(expr.p), self._print(expr.q))
def _print_PythonRational(self, expr):
return "%s(%d, %d)" % (expr.__class__.__name__, expr.p, expr.q)
def _print_Fraction(self, expr):
return 'Fraction(%s, %s)' % (self._print(expr.numerator), self._print(expr.denominator))
def _print_Float(self, expr):
r = mlib.to_str(expr._mpf_, repr_dps(expr._prec))
return "%s('%s', precision=%i)" % (expr.__class__.__name__, r, expr._prec)
def _print_Sum2(self, expr):
return "Sum2(%s, (%s, %s, %s))" % (self._print(expr.f), self._print(expr.i),
self._print(expr.a), self._print(expr.b))
def _print_Symbol(self, expr):
d = expr._assumptions.generator
# print the dummy_index like it was an assumption
if expr.is_Dummy:
d['dummy_index'] = expr.dummy_index
if d == {}:
return "%s(%s)" % (expr.__class__.__name__, self._print(expr.name))
else:
attr = ['%s=%s' % (k, v) for k, v in d.items()]
return "%s(%s, %s)" % (expr.__class__.__name__,
self._print(expr.name), ', '.join(attr))
def _print_Predicate(self, expr):
return "%s(%s)" % (expr.__class__.__name__, self._print(expr.name))
def _print_AppliedPredicate(self, expr):
return "%s(%s, %s)" % (expr.__class__.__name__, expr.func, expr.arg)
def _print_str(self, expr):
return repr(expr)
def _print_tuple(self, expr):
if len(expr) == 1:
return "(%s,)" % self._print(expr[0])
else:
return "(%s)" % self.reprify(expr, ", ")
def _print_WildFunction(self, expr):
return "%s('%s')" % (expr.__class__.__name__, expr.name)
def _print_AlgebraicNumber(self, expr):
return "%s(%s, %s)" % (expr.__class__.__name__,
self._print(expr.root), self._print(expr.coeffs()))
def _print_PolyRing(self, ring):
return "%s(%s, %s, %s)" % (ring.__class__.__name__,
self._print(ring.symbols), self._print(ring.domain), self._print(ring.order))
def _print_FracField(self, field):
return "%s(%s, %s, %s)" % (field.__class__.__name__,
self._print(field.symbols), self._print(field.domain), self._print(field.order))
def _print_PolyElement(self, poly):
terms = list(poly.terms())
terms.sort(key=poly.ring.order, reverse=True)
return "%s(%s, %s)" % (poly.__class__.__name__, self._print(poly.ring), self._print(terms))
def _print_FracElement(self, frac):
numer_terms = list(frac.numer.terms())
numer_terms.sort(key=frac.field.order, reverse=True)
denom_terms = list(frac.denom.terms())
denom_terms.sort(key=frac.field.order, reverse=True)
numer = self._print(numer_terms)
denom = self._print(denom_terms)
return "%s(%s, %s, %s)" % (frac.__class__.__name__, self._print(frac.field), numer, denom)
def _print_FractionField(self, domain):
cls = domain.__class__.__name__
field = self._print(domain.field)
return "%s(%s)" % (cls, field)
def _print_PolynomialRingBase(self, ring):
cls = ring.__class__.__name__
dom = self._print(ring.domain)
gens = ', '.join(map(self._print, ring.gens))
order = str(ring.order)
if order != ring.default_order:
orderstr = ", order=" + order
else:
orderstr = ""
return "%s(%s, %s%s)" % (cls, dom, gens, orderstr)
def _print_DMP(self, p):
cls = p.__class__.__name__
rep = self._print(p.rep)
dom = self._print(p.dom)
if p.ring is not None:
ringstr = ", ring=" + self._print(p.ring)
else:
ringstr = ""
return "%s(%s, %s%s)" % (cls, rep, dom, ringstr)
def _print_MonogenicFiniteExtension(self, ext):
# The expanded tree shown by srepr(ext.modulus)
# is not practical.
return "FiniteExtension(%s)" % str(ext.modulus)
def _print_ExtensionElement(self, f):
rep = self._print(f.rep)
ext = self._print(f.ext)
return "ExtElem(%s, %s)" % (rep, ext)
def srepr(expr, **settings):
"""return expr in repr form"""
return ReprPrinter(settings).doprint(expr)
|
cbe8ce537af669052700de68bdac5e66881deb6725c1b9d492c5d4937215588d
|
"""Integration method that emulates by-hand techniques.
This module also provides functionality to get the steps used to evaluate a
particular integral, in the ``integral_steps`` function. This will return
nested namedtuples representing the integration rules used. The
``manualintegrate`` function computes the integral using those steps given
an integrand; given the steps, ``_manualintegrate`` will evaluate them.
The integrator can be extended with new heuristics and evaluation
techniques. To do so, write a function that accepts an ``IntegralInfo``
object and returns either a namedtuple representing a rule or
``None``. Then, write another function that accepts the namedtuple's fields
and returns the antiderivative, and decorate it with
``@evaluates(namedtuple_type)``. If the new technique requires a new
match, add the key and call to the antiderivative function to integral_steps.
To enable simple substitutions, add the match to find_substitutions.
"""
from __future__ import print_function, division
from collections import namedtuple, defaultdict
import sympy
from sympy.core.compatibility import reduce, Mapping
from sympy.core.containers import Dict
from sympy.core.logic import fuzzy_not
from sympy.functions.elementary.trigonometric import TrigonometricFunction
from sympy.functions.special.polynomials import OrthogonalPolynomial
from sympy.functions.elementary.piecewise import Piecewise
from sympy.strategies.core import switch, do_one, null_safe, condition
from sympy.core.relational import Eq, Ne
from sympy.polys.polytools import degree
from sympy.ntheory.factor_ import divisors
ZERO = sympy.S.Zero
def Rule(name, props=""):
# GOTCHA: namedtuple class name not considered!
def __eq__(self, other):
return self.__class__ == other.__class__ and tuple.__eq__(self, other)
__neq__ = lambda self, other: not __eq__(self, other)
cls = namedtuple(name, props + " context symbol")
cls.__eq__ = __eq__
cls.__ne__ = __neq__
return cls
ConstantRule = Rule("ConstantRule", "constant")
ConstantTimesRule = Rule("ConstantTimesRule", "constant other substep")
PowerRule = Rule("PowerRule", "base exp")
AddRule = Rule("AddRule", "substeps")
URule = Rule("URule", "u_var u_func constant substep")
PartsRule = Rule("PartsRule", "u dv v_step second_step")
CyclicPartsRule = Rule("CyclicPartsRule", "parts_rules coefficient")
TrigRule = Rule("TrigRule", "func arg")
ExpRule = Rule("ExpRule", "base exp")
ReciprocalRule = Rule("ReciprocalRule", "func")
ArcsinRule = Rule("ArcsinRule")
InverseHyperbolicRule = Rule("InverseHyperbolicRule", "func")
AlternativeRule = Rule("AlternativeRule", "alternatives")
DontKnowRule = Rule("DontKnowRule")
DerivativeRule = Rule("DerivativeRule")
RewriteRule = Rule("RewriteRule", "rewritten substep")
PiecewiseRule = Rule("PiecewiseRule", "subfunctions")
HeavisideRule = Rule("HeavisideRule", "harg ibnd substep")
TrigSubstitutionRule = Rule("TrigSubstitutionRule",
"theta func rewritten substep restriction")
ArctanRule = Rule("ArctanRule", "a b c")
ArccothRule = Rule("ArccothRule", "a b c")
ArctanhRule = Rule("ArctanhRule", "a b c")
JacobiRule = Rule("JacobiRule", "n a b")
GegenbauerRule = Rule("GegenbauerRule", "n a")
ChebyshevTRule = Rule("ChebyshevTRule", "n")
ChebyshevURule = Rule("ChebyshevURule", "n")
LegendreRule = Rule("LegendreRule", "n")
HermiteRule = Rule("HermiteRule", "n")
LaguerreRule = Rule("LaguerreRule", "n")
AssocLaguerreRule = Rule("AssocLaguerreRule", "n a")
CiRule = Rule("CiRule", "a b")
ChiRule = Rule("ChiRule", "a b")
EiRule = Rule("EiRule", "a b")
SiRule = Rule("SiRule", "a b")
ShiRule = Rule("ShiRule", "a b")
ErfRule = Rule("ErfRule", "a b c")
FresnelCRule = Rule("FresnelCRule", "a b c")
FresnelSRule = Rule("FresnelSRule", "a b c")
LiRule = Rule("LiRule", "a b")
PolylogRule = Rule("PolylogRule", "a b")
UpperGammaRule = Rule("UpperGammaRule", "a e")
EllipticFRule = Rule("EllipticFRule", "a d")
EllipticERule = Rule("EllipticERule", "a d")
IntegralInfo = namedtuple('IntegralInfo', 'integrand symbol')
evaluators = {}
def evaluates(rule):
def _evaluates(func):
func.rule = rule
evaluators[rule] = func
return func
return _evaluates
def contains_dont_know(rule):
if isinstance(rule, DontKnowRule):
return True
else:
for val in rule:
if isinstance(val, tuple):
if contains_dont_know(val):
return True
elif isinstance(val, list):
if any(contains_dont_know(i) for i in val):
return True
return False
def manual_diff(f, symbol):
"""Derivative of f in form expected by find_substitutions
SymPy's derivatives for some trig functions (like cot) aren't in a form
that works well with finding substitutions; this replaces the
derivatives for those particular forms with something that works better.
"""
if f.args:
arg = f.args[0]
if isinstance(f, sympy.tan):
return arg.diff(symbol) * sympy.sec(arg)**2
elif isinstance(f, sympy.cot):
return -arg.diff(symbol) * sympy.csc(arg)**2
elif isinstance(f, sympy.sec):
return arg.diff(symbol) * sympy.sec(arg) * sympy.tan(arg)
elif isinstance(f, sympy.csc):
return -arg.diff(symbol) * sympy.csc(arg) * sympy.cot(arg)
elif isinstance(f, sympy.Add):
return sum([manual_diff(arg, symbol) for arg in f.args])
elif isinstance(f, sympy.Mul):
if len(f.args) == 2 and isinstance(f.args[0], sympy.Number):
return f.args[0] * manual_diff(f.args[1], symbol)
return f.diff(symbol)
def manual_subs(expr, *args):
"""
A wrapper for `expr.subs(*args)` with additional logic for substitution
of invertible functions.
"""
if len(args) == 1:
sequence = args[0]
if isinstance(sequence, (Dict, Mapping)):
sequence = sequence.items()
elif not iterable(sequence):
raise ValueError("Expected an iterable of (old, new) pairs")
elif len(args) == 2:
sequence = [args]
else:
raise ValueError("subs accepts either 1 or 2 arguments")
new_subs = []
for old, new in sequence:
if isinstance(old, sympy.log):
# If log(x) = y, then exp(a*log(x)) = exp(a*y)
# that is, x**a = exp(a*y). Replace nontrivial powers of x
# before subs turns them into `exp(y)**a`, but
# do not replace x itself yet, to avoid `log(exp(y))`.
a = sympy.Wild('a')
expr = expr.replace(old.args[0]**(1 + a),
sympy.exp((1 + a)*new), exact=True)
new_subs.append((old.args[0], sympy.exp(new)))
return expr.subs(list(sequence) + new_subs)
# Method based on that on SIN, described in "Symbolic Integration: The
# Stormy Decade"
def find_substitutions(integrand, symbol, u_var):
results = []
def test_subterm(u, u_diff):
substituted = integrand / u_diff
if symbol not in substituted.free_symbols:
# replaced everything already
return False
substituted = manual_subs(substituted, u, u_var).cancel()
if symbol not in substituted.free_symbols:
# avoid increasing the degree of a rational function
if integrand.is_rational_function(symbol) and substituted.is_rational_function(u_var):
deg_before = max([degree(t, symbol) for t in integrand.as_numer_denom()])
deg_after = max([degree(t, u_var) for t in substituted.as_numer_denom()])
if deg_after > deg_before:
return False
return substituted.as_independent(u_var, as_Add=False)
# special treatment for substitutions u = (a*x+b)**(1/n)
if (isinstance(u, sympy.Pow) and (1/u.exp).is_Integer and
sympy.Abs(u.exp) < 1):
a = sympy.Wild('a', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
match = u.base.match(a*symbol + b)
if match:
a, b = [match.get(i, ZERO) for i in (a, b)]
if a != 0 and b != 0:
substituted = substituted.subs(symbol,
(u_var**(1/u.exp) - b)/a)
return substituted.as_independent(u_var, as_Add=False)
return False
def possible_subterms(term):
if isinstance(term, (TrigonometricFunction,
sympy.asin, sympy.acos, sympy.atan,
sympy.exp, sympy.log, sympy.Heaviside)):
return [term.args[0]]
elif isinstance(term, (sympy.chebyshevt, sympy.chebyshevu,
sympy.legendre, sympy.hermite, sympy.laguerre)):
return [term.args[1]]
elif isinstance(term, (sympy.gegenbauer, sympy.assoc_laguerre)):
return [term.args[2]]
elif isinstance(term, sympy.jacobi):
return [term.args[3]]
elif isinstance(term, sympy.Mul):
r = []
for u in term.args:
r.append(u)
r.extend(possible_subterms(u))
return r
elif isinstance(term, sympy.Pow):
r = []
if term.args[1].is_constant(symbol):
r.append(term.args[0])
elif term.args[0].is_constant(symbol):
r.append(term.args[1])
if term.args[1].is_Integer:
r.extend([term.args[0]**d for d in divisors(term.args[1])
if 1 < d < abs(term.args[1])])
if term.args[0].is_Add:
r.extend([t for t in possible_subterms(term.args[0])
if t.is_Pow])
return r
elif isinstance(term, sympy.Add):
r = []
for arg in term.args:
r.append(arg)
r.extend(possible_subterms(arg))
return r
return []
for u in possible_subterms(integrand):
if u == symbol:
continue
u_diff = manual_diff(u, symbol)
new_integrand = test_subterm(u, u_diff)
if new_integrand is not False:
constant, new_integrand = new_integrand
if new_integrand == integrand.subs(symbol, u_var):
continue
substitution = (u, constant, new_integrand)
if substitution not in results:
results.append(substitution)
return results
def rewriter(condition, rewrite):
"""Strategy that rewrites an integrand."""
def _rewriter(integral):
integrand, symbol = integral
if condition(*integral):
rewritten = rewrite(*integral)
if rewritten != integrand:
substep = integral_steps(rewritten, symbol)
if not isinstance(substep, DontKnowRule) and substep:
return RewriteRule(
rewritten,
substep,
integrand, symbol)
return _rewriter
def proxy_rewriter(condition, rewrite):
"""Strategy that rewrites an integrand based on some other criteria."""
def _proxy_rewriter(criteria):
criteria, integral = criteria
integrand, symbol = integral
args = criteria + list(integral)
if condition(*args):
rewritten = rewrite(*args)
if rewritten != integrand:
return RewriteRule(
rewritten,
integral_steps(rewritten, symbol),
integrand, symbol)
return _proxy_rewriter
def multiplexer(conditions):
"""Apply the rule that matches the condition, else None"""
def multiplexer_rl(expr):
for key, rule in conditions.items():
if key(expr):
return rule(expr)
return multiplexer_rl
def alternatives(*rules):
"""Strategy that makes an AlternativeRule out of multiple possible results."""
def _alternatives(integral):
alts = []
for rule in rules:
result = rule(integral)
if (result and not isinstance(result, DontKnowRule) and
result != integral and result not in alts):
alts.append(result)
if len(alts) == 1:
return alts[0]
elif alts:
doable = [rule for rule in alts if not contains_dont_know(rule)]
if doable:
return AlternativeRule(doable, *integral)
else:
return AlternativeRule(alts, *integral)
return _alternatives
def constant_rule(integral):
integrand, symbol = integral
return ConstantRule(integral.integrand, *integral)
def power_rule(integral):
integrand, symbol = integral
base, exp = integrand.as_base_exp()
if symbol not in exp.free_symbols and isinstance(base, sympy.Symbol):
if sympy.simplify(exp + 1) == 0:
return ReciprocalRule(base, integrand, symbol)
return PowerRule(base, exp, integrand, symbol)
elif symbol not in base.free_symbols and isinstance(exp, sympy.Symbol):
rule = ExpRule(base, exp, integrand, symbol)
if fuzzy_not(sympy.log(base).is_zero):
return rule
elif sympy.log(base).is_zero:
return ConstantRule(1, 1, symbol)
return PiecewiseRule([
(rule, sympy.Ne(sympy.log(base), 0)),
(ConstantRule(1, 1, symbol), True)
], integrand, symbol)
def exp_rule(integral):
integrand, symbol = integral
if isinstance(integrand.args[0], sympy.Symbol):
return ExpRule(sympy.E, integrand.args[0], integrand, symbol)
def orthogonal_poly_rule(integral):
orthogonal_poly_classes = {
sympy.jacobi: JacobiRule,
sympy.gegenbauer: GegenbauerRule,
sympy.chebyshevt: ChebyshevTRule,
sympy.chebyshevu: ChebyshevURule,
sympy.legendre: LegendreRule,
sympy.hermite: HermiteRule,
sympy.laguerre: LaguerreRule,
sympy.assoc_laguerre: AssocLaguerreRule
}
orthogonal_poly_var_index = {
sympy.jacobi: 3,
sympy.gegenbauer: 2,
sympy.assoc_laguerre: 2
}
integrand, symbol = integral
for klass in orthogonal_poly_classes:
if isinstance(integrand, klass):
var_index = orthogonal_poly_var_index.get(klass, 1)
if (integrand.args[var_index] is symbol and not
any(v.has(symbol) for v in integrand.args[:var_index])):
args = integrand.args[:var_index] + (integrand, symbol)
return orthogonal_poly_classes[klass](*args)
def special_function_rule(integral):
integrand, symbol = integral
a = sympy.Wild('a', exclude=[symbol], properties=[lambda x: not x.is_zero])
b = sympy.Wild('b', exclude=[symbol])
c = sympy.Wild('c', exclude=[symbol])
d = sympy.Wild('d', exclude=[symbol], properties=[lambda x: not x.is_zero])
e = sympy.Wild('e', exclude=[symbol], properties=[
lambda x: not (x.is_nonnegative and x.is_integer)])
wilds = (a, b, c, d, e)
# patterns consist of a SymPy class, a wildcard expr, an optional
# condition coded as a lambda (when Wild properties are not enough),
# followed by an applicable rule
patterns = (
(sympy.Mul, sympy.exp(a*symbol + b)/symbol, None, EiRule),
(sympy.Mul, sympy.cos(a*symbol + b)/symbol, None, CiRule),
(sympy.Mul, sympy.cosh(a*symbol + b)/symbol, None, ChiRule),
(sympy.Mul, sympy.sin(a*symbol + b)/symbol, None, SiRule),
(sympy.Mul, sympy.sinh(a*symbol + b)/symbol, None, ShiRule),
(sympy.Pow, 1/sympy.log(a*symbol + b), None, LiRule),
(sympy.exp, sympy.exp(a*symbol**2 + b*symbol + c), None, ErfRule),
(sympy.sin, sympy.sin(a*symbol**2 + b*symbol + c), None, FresnelSRule),
(sympy.cos, sympy.cos(a*symbol**2 + b*symbol + c), None, FresnelCRule),
(sympy.Mul, symbol**e*sympy.exp(a*symbol), None, UpperGammaRule),
(sympy.Mul, sympy.polylog(b, a*symbol)/symbol, None, PolylogRule),
(sympy.Pow, 1/sympy.sqrt(a - d*sympy.sin(symbol)**2),
lambda a, d: a != d, EllipticFRule),
(sympy.Pow, sympy.sqrt(a - d*sympy.sin(symbol)**2),
lambda a, d: a != d, EllipticERule),
)
for p in patterns:
if isinstance(integrand, p[0]):
match = integrand.match(p[1])
if match:
wild_vals = tuple(match.get(w) for w in wilds
if match.get(w) is not None)
if p[2] is None or p[2](*wild_vals):
args = wild_vals + (integrand, symbol)
return p[3](*args)
def inverse_trig_rule(integral):
integrand, symbol = integral
base, exp = integrand.as_base_exp()
a = sympy.Wild('a', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
match = base.match(a + b*symbol**2)
if not match:
return
def negative(x):
return x.is_negative or x.could_extract_minus_sign()
def ArcsinhRule(integrand, symbol):
return InverseHyperbolicRule(sympy.asinh, integrand, symbol)
def ArccoshRule(integrand, symbol):
return InverseHyperbolicRule(sympy.acosh, integrand, symbol)
def make_inverse_trig(RuleClass, base_exp, a, sign_a, b, sign_b):
u_var = sympy.Dummy("u")
current_base = base
current_symbol = symbol
constant = u_func = u_constant = substep = None
factored = integrand
if a != 1:
constant = a**base_exp
current_base = sign_a + sign_b * (b/a) * current_symbol**2
factored = current_base ** base_exp
if (b/a) != 1:
u_func = sympy.sqrt(b/a) * symbol
u_constant = sympy.sqrt(a/b)
current_symbol = u_var
current_base = sign_a + sign_b * current_symbol**2
substep = RuleClass(current_base ** base_exp, current_symbol)
if u_func is not None:
if u_constant != 1 and substep is not None:
substep = ConstantTimesRule(
u_constant, current_base ** base_exp, substep,
u_constant * current_base ** base_exp, symbol)
substep = URule(u_var, u_func, u_constant, substep, factored, symbol)
if constant is not None and substep is not None:
substep = ConstantTimesRule(constant, factored, substep, integrand, symbol)
return substep
a, b = [match.get(i, ZERO) for i in (a, b)]
# list of (rule, base_exp, a, sign_a, b, sign_b, condition)
possibilities = []
if sympy.simplify(2*exp + 1) == 0:
possibilities.append((ArcsinRule, exp, a, 1, -b, -1, sympy.And(a > 0, b < 0)))
possibilities.append((ArcsinhRule, exp, a, 1, b, 1, sympy.And(a > 0, b > 0)))
possibilities.append((ArccoshRule, exp, -a, -1, b, 1, sympy.And(a < 0, b > 0)))
possibilities = [p for p in possibilities if p[-1] is not sympy.false]
if a.is_number and b.is_number:
possibility = [p for p in possibilities if p[-1] is sympy.true]
if len(possibility) == 1:
return make_inverse_trig(*possibility[0][:-1])
elif possibilities:
return PiecewiseRule(
[(make_inverse_trig(*p[:-1]), p[-1]) for p in possibilities],
integrand, symbol)
def add_rule(integral):
integrand, symbol = integral
results = [integral_steps(g, symbol)
for g in integrand.as_ordered_terms()]
return None if None in results else AddRule(results, integrand, symbol)
def mul_rule(integral):
integrand, symbol = integral
args = integrand.args
# Constant times function case
coeff, f = integrand.as_independent(symbol)
next_step = integral_steps(f, symbol)
if coeff != 1 and next_step is not None:
return ConstantTimesRule(
coeff, f,
next_step,
integrand, symbol)
def _parts_rule(integrand, symbol):
# LIATE rule:
# log, inverse trig, algebraic, trigonometric, exponential
def pull_out_algebraic(integrand):
integrand = integrand.cancel().together()
# iterating over Piecewise args would not work here
algebraic = ([] if isinstance(integrand, sympy.Piecewise)
else [arg for arg in integrand.args if arg.is_algebraic_expr(symbol)])
if algebraic:
u = sympy.Mul(*algebraic)
dv = (integrand / u).cancel()
return u, dv
def pull_out_u(*functions):
def pull_out_u_rl(integrand):
if any([integrand.has(f) for f in functions]):
args = [arg for arg in integrand.args
if any(isinstance(arg, cls) for cls in functions)]
if args:
u = reduce(lambda a,b: a*b, args)
dv = integrand / u
return u, dv
return pull_out_u_rl
liate_rules = [pull_out_u(sympy.log), pull_out_u(sympy.atan, sympy.asin, sympy.acos),
pull_out_algebraic, pull_out_u(sympy.sin, sympy.cos),
pull_out_u(sympy.exp)]
dummy = sympy.Dummy("temporary")
# we can integrate log(x) and atan(x) by setting dv = 1
if isinstance(integrand, (sympy.log, sympy.atan, sympy.asin, sympy.acos)):
integrand = dummy * integrand
for index, rule in enumerate(liate_rules):
result = rule(integrand)
if result:
u, dv = result
# Don't pick u to be a constant if possible
if symbol not in u.free_symbols and not u.has(dummy):
return
u = u.subs(dummy, 1)
dv = dv.subs(dummy, 1)
# Don't pick a non-polynomial algebraic to be differentiated
if rule == pull_out_algebraic and not u.is_polynomial(symbol):
return
# Don't trade one logarithm for another
if isinstance(u, sympy.log):
rec_dv = 1/dv
if (rec_dv.is_polynomial(symbol) and
degree(rec_dv, symbol) == 1):
return
# Can integrate a polynomial times OrthogonalPolynomial
if rule == pull_out_algebraic and isinstance(dv, OrthogonalPolynomial):
v_step = integral_steps(dv, symbol)
if contains_dont_know(v_step):
return
else:
du = u.diff(symbol)
v = _manualintegrate(v_step)
return u, dv, v, du, v_step
# make sure dv is amenable to integration
accept = False
if index < 2: # log and inverse trig are usually worth trying
accept = True
elif (rule == pull_out_algebraic and dv.args and
all(isinstance(a, (sympy.sin, sympy.cos, sympy.exp))
for a in dv.args)):
accept = True
else:
for rule in liate_rules[index + 1:]:
r = rule(integrand)
if r and r[0].subs(dummy, 1).equals(dv):
accept = True
break
if accept:
du = u.diff(symbol)
v_step = integral_steps(sympy.simplify(dv), symbol)
if not contains_dont_know(v_step):
v = _manualintegrate(v_step)
return u, dv, v, du, v_step
def parts_rule(integral):
integrand, symbol = integral
constant, integrand = integrand.as_coeff_Mul()
result = _parts_rule(integrand, symbol)
steps = []
if result:
u, dv, v, du, v_step = result
steps.append(result)
if isinstance(v, sympy.Integral):
return
# Set a limit on the number of times u can be used
if isinstance(u, (sympy.sin, sympy.cos, sympy.exp, sympy.sinh, sympy.cosh)):
cachekey = u.xreplace({symbol: _cache_dummy})
if _parts_u_cache[cachekey] > 2:
return
_parts_u_cache[cachekey] += 1
# Try cyclic integration by parts a few times
for _ in range(4):
coefficient = ((v * du) / integrand).cancel()
if coefficient == 1:
break
if symbol not in coefficient.free_symbols:
rule = CyclicPartsRule(
[PartsRule(u, dv, v_step, None, None, None)
for (u, dv, v, du, v_step) in steps],
(-1) ** len(steps) * coefficient,
integrand, symbol
)
if (constant != 1) and rule:
rule = ConstantTimesRule(constant, integrand, rule,
constant * integrand, symbol)
return rule
# _parts_rule is sensitive to constants, factor it out
next_constant, next_integrand = (v * du).as_coeff_Mul()
result = _parts_rule(next_integrand, symbol)
if result:
u, dv, v, du, v_step = result
u *= next_constant
du *= next_constant
steps.append((u, dv, v, du, v_step))
else:
break
def make_second_step(steps, integrand):
if steps:
u, dv, v, du, v_step = steps[0]
return PartsRule(u, dv, v_step,
make_second_step(steps[1:], v * du),
integrand, symbol)
else:
steps = integral_steps(integrand, symbol)
if steps:
return steps
else:
return DontKnowRule(integrand, symbol)
if steps:
u, dv, v, du, v_step = steps[0]
rule = PartsRule(u, dv, v_step,
make_second_step(steps[1:], v * du),
integrand, symbol)
if (constant != 1) and rule:
rule = ConstantTimesRule(constant, integrand, rule,
constant * integrand, symbol)
return rule
def trig_rule(integral):
integrand, symbol = integral
if isinstance(integrand, sympy.sin) or isinstance(integrand, sympy.cos):
arg = integrand.args[0]
if not isinstance(arg, sympy.Symbol):
return # perhaps a substitution can deal with it
if isinstance(integrand, sympy.sin):
func = 'sin'
else:
func = 'cos'
return TrigRule(func, arg, integrand, symbol)
if integrand == sympy.sec(symbol)**2:
return TrigRule('sec**2', symbol, integrand, symbol)
elif integrand == sympy.csc(symbol)**2:
return TrigRule('csc**2', symbol, integrand, symbol)
if isinstance(integrand, sympy.tan):
rewritten = sympy.sin(*integrand.args) / sympy.cos(*integrand.args)
elif isinstance(integrand, sympy.cot):
rewritten = sympy.cos(*integrand.args) / sympy.sin(*integrand.args)
elif isinstance(integrand, sympy.sec):
arg = integrand.args[0]
rewritten = ((sympy.sec(arg)**2 + sympy.tan(arg) * sympy.sec(arg)) /
(sympy.sec(arg) + sympy.tan(arg)))
elif isinstance(integrand, sympy.csc):
arg = integrand.args[0]
rewritten = ((sympy.csc(arg)**2 + sympy.cot(arg) * sympy.csc(arg)) /
(sympy.csc(arg) + sympy.cot(arg)))
else:
return
return RewriteRule(
rewritten,
integral_steps(rewritten, symbol),
integrand, symbol
)
def trig_product_rule(integral):
integrand, symbol = integral
sectan = sympy.sec(symbol) * sympy.tan(symbol)
q = integrand / sectan
if symbol not in q.free_symbols:
rule = TrigRule('sec*tan', symbol, sectan, symbol)
if q != 1 and rule:
rule = ConstantTimesRule(q, sectan, rule, integrand, symbol)
return rule
csccot = -sympy.csc(symbol) * sympy.cot(symbol)
q = integrand / csccot
if symbol not in q.free_symbols:
rule = TrigRule('csc*cot', symbol, csccot, symbol)
if q != 1 and rule:
rule = ConstantTimesRule(q, csccot, rule, integrand, symbol)
return rule
def quadratic_denom_rule(integral):
integrand, symbol = integral
a = sympy.Wild('a', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
c = sympy.Wild('c', exclude=[symbol])
match = integrand.match(a / (b * symbol ** 2 + c))
if not match:
return
a, b, c = match[a], match[b], match[c]
return PiecewiseRule([(ArctanRule(a, b, c, integrand, symbol), sympy.Gt(c / b, 0)),
(ArccothRule(a, b, c, integrand, symbol), sympy.And(sympy.Gt(symbol ** 2, -c / b), sympy.Lt(c / b, 0))),
(ArctanhRule(a, b, c, integrand, symbol), sympy.And(sympy.Lt(symbol ** 2, -c / b), sympy.Lt(c / b, 0))),
], integrand, symbol)
def root_mul_rule(integral):
integrand, symbol = integral
a = sympy.Wild('a', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
c = sympy.Wild('c')
match = integrand.match(sympy.sqrt(a * symbol + b) * c)
if not match:
return
a, b, c = match[a], match[b], match[c]
d = sympy.Wild('d', exclude=[symbol])
e = sympy.Wild('e', exclude=[symbol])
f = sympy.Wild('f')
recursion_test = c.match(sympy.sqrt(d * symbol + e) * f)
if recursion_test:
return
u = sympy.Dummy('u')
u_func = sympy.sqrt(a * symbol + b)
integrand = integrand.subs(u_func, u)
integrand = integrand.subs(symbol, (u**2 - b) / a)
integrand = integrand * 2 * u / a
next_step = integral_steps(integrand, u)
if next_step:
return URule(u, u_func, None, next_step, integrand, symbol)
@sympy.cacheit
def make_wilds(symbol):
a = sympy.Wild('a', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
m = sympy.Wild('m', exclude=[symbol], properties=[lambda n: isinstance(n, sympy.Integer)])
n = sympy.Wild('n', exclude=[symbol], properties=[lambda n: isinstance(n, sympy.Integer)])
return a, b, m, n
@sympy.cacheit
def sincos_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = sympy.sin(a*symbol)**m * sympy.cos(b*symbol)**n
return pattern, a, b, m, n
@sympy.cacheit
def tansec_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = sympy.tan(a*symbol)**m * sympy.sec(b*symbol)**n
return pattern, a, b, m, n
@sympy.cacheit
def cotcsc_pattern(symbol):
a, b, m, n = make_wilds(symbol)
pattern = sympy.cot(a*symbol)**m * sympy.csc(b*symbol)**n
return pattern, a, b, m, n
@sympy.cacheit
def heaviside_pattern(symbol):
m = sympy.Wild('m', exclude=[symbol])
b = sympy.Wild('b', exclude=[symbol])
g = sympy.Wild('g')
pattern = sympy.Heaviside(m*symbol + b) * g
return pattern, m, b, g
def uncurry(func):
def uncurry_rl(args):
return func(*args)
return uncurry_rl
def trig_rewriter(rewrite):
def trig_rewriter_rl(args):
a, b, m, n, integrand, symbol = args
rewritten = rewrite(a, b, m, n, integrand, symbol)
if rewritten != integrand:
return RewriteRule(
rewritten,
integral_steps(rewritten, symbol),
integrand, symbol)
return trig_rewriter_rl
sincos_botheven_condition = uncurry(
lambda a, b, m, n, i, s: m.is_even and n.is_even and
m.is_nonnegative and n.is_nonnegative)
sincos_botheven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (((1 - sympy.cos(2*a*symbol)) / 2) ** (m / 2)) *
(((1 + sympy.cos(2*b*symbol)) / 2) ** (n / 2)) ))
sincos_sinodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd and m >= 3)
sincos_sinodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 - sympy.cos(a*symbol)**2)**((m - 1) / 2) *
sympy.sin(a*symbol) *
sympy.cos(b*symbol) ** n))
sincos_cosodd_condition = uncurry(lambda a, b, m, n, i, s: n.is_odd and n >= 3)
sincos_cosodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 - sympy.sin(b*symbol)**2)**((n - 1) / 2) *
sympy.cos(b*symbol) *
sympy.sin(a*symbol) ** m))
tansec_seceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
tansec_seceven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 + sympy.tan(b*symbol)**2) ** (n/2 - 1) *
sympy.sec(b*symbol)**2 *
sympy.tan(a*symbol) ** m ))
tansec_tanodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
tansec_tanodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (sympy.sec(a*symbol)**2 - 1) ** ((m - 1) / 2) *
sympy.tan(a*symbol) *
sympy.sec(b*symbol) ** n ))
tan_tansquared_condition = uncurry(lambda a, b, m, n, i, s: m == 2 and n == 0)
tan_tansquared = trig_rewriter(
lambda a, b, m, n, i, symbol: ( sympy.sec(a*symbol)**2 - 1))
cotcsc_csceven_condition = uncurry(lambda a, b, m, n, i, s: n.is_even and n >= 4)
cotcsc_csceven = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (1 + sympy.cot(b*symbol)**2) ** (n/2 - 1) *
sympy.csc(b*symbol)**2 *
sympy.cot(a*symbol) ** m ))
cotcsc_cotodd_condition = uncurry(lambda a, b, m, n, i, s: m.is_odd)
cotcsc_cotodd = trig_rewriter(
lambda a, b, m, n, i, symbol: ( (sympy.csc(a*symbol)**2 - 1) ** ((m - 1) / 2) *
sympy.cot(a*symbol) *
sympy.csc(b*symbol) ** n ))
def trig_sincos_rule(integral):
integrand, symbol = integral
if any(integrand.has(f) for f in (sympy.sin, sympy.cos)):
pattern, a, b, m, n = sincos_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
sincos_botheven_condition: sincos_botheven,
sincos_sinodd_condition: sincos_sinodd,
sincos_cosodd_condition: sincos_cosodd
})(tuple(
[match.get(i, ZERO) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_tansec_rule(integral):
integrand, symbol = integral
integrand = integrand.subs({
1 / sympy.cos(symbol): sympy.sec(symbol)
})
if any(integrand.has(f) for f in (sympy.tan, sympy.sec)):
pattern, a, b, m, n = tansec_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
tansec_tanodd_condition: tansec_tanodd,
tansec_seceven_condition: tansec_seceven,
tan_tansquared_condition: tan_tansquared
})(tuple(
[match.get(i, ZERO) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_cotcsc_rule(integral):
integrand, symbol = integral
integrand = integrand.subs({
1 / sympy.sin(symbol): sympy.csc(symbol),
1 / sympy.tan(symbol): sympy.cot(symbol),
sympy.cos(symbol) / sympy.tan(symbol): sympy.cot(symbol)
})
if any(integrand.has(f) for f in (sympy.cot, sympy.csc)):
pattern, a, b, m, n = cotcsc_pattern(symbol)
match = integrand.match(pattern)
if not match:
return
return multiplexer({
cotcsc_cotodd_condition: cotcsc_cotodd,
cotcsc_csceven_condition: cotcsc_csceven
})(tuple(
[match.get(i, ZERO) for i in (a, b, m, n)] +
[integrand, symbol]))
def trig_sindouble_rule(integral):
integrand, symbol = integral
a = sympy.Wild('a', exclude=[sympy.sin(2*symbol)])
match = integrand.match(sympy.sin(2*symbol)*a)
if match:
sin_double = 2*sympy.sin(symbol)*sympy.cos(symbol)/sympy.sin(2*symbol)
return integral_steps(integrand * sin_double, symbol)
def trig_powers_products_rule(integral):
return do_one(null_safe(trig_sincos_rule),
null_safe(trig_tansec_rule),
null_safe(trig_cotcsc_rule),
null_safe(trig_sindouble_rule))(integral)
def trig_substitution_rule(integral):
integrand, symbol = integral
A = sympy.Wild('a', exclude=[0, symbol])
B = sympy.Wild('b', exclude=[0, symbol])
theta = sympy.Dummy("theta")
target_pattern = A + B*symbol**2
matches = integrand.find(target_pattern)
for expr in matches:
match = expr.match(target_pattern)
a = match.get(A, ZERO)
b = match.get(B, ZERO)
a_positive = ((a.is_number and a > 0) or a.is_positive)
b_positive = ((b.is_number and b > 0) or b.is_positive)
a_negative = ((a.is_number and a < 0) or a.is_negative)
b_negative = ((b.is_number and b < 0) or b.is_negative)
x_func = None
if a_positive and b_positive:
# a**2 + b*x**2. Assume sec(theta) > 0, -pi/2 < theta < pi/2
x_func = (sympy.sqrt(a)/sympy.sqrt(b)) * sympy.tan(theta)
# Do not restrict the domain: tan(theta) takes on any real
# value on the interval -pi/2 < theta < pi/2 so x takes on
# any value
restriction = True
elif a_positive and b_negative:
# a**2 - b*x**2. Assume cos(theta) > 0, -pi/2 < theta < pi/2
constant = sympy.sqrt(a)/sympy.sqrt(-b)
x_func = constant * sympy.sin(theta)
restriction = sympy.And(symbol > -constant, symbol < constant)
elif a_negative and b_positive:
# b*x**2 - a**2. Assume sin(theta) > 0, 0 < theta < pi
constant = sympy.sqrt(-a)/sympy.sqrt(b)
x_func = constant * sympy.sec(theta)
restriction = sympy.And(symbol > -constant, symbol < constant)
if x_func:
# Manually simplify sqrt(trig(theta)**2) to trig(theta)
# Valid due to assumed domain restriction
substitutions = {}
for f in [sympy.sin, sympy.cos, sympy.tan,
sympy.sec, sympy.csc, sympy.cot]:
substitutions[sympy.sqrt(f(theta)**2)] = f(theta)
substitutions[sympy.sqrt(f(theta)**(-2))] = 1/f(theta)
replaced = integrand.subs(symbol, x_func).trigsimp()
replaced = manual_subs(replaced, substitutions)
if not replaced.has(symbol):
replaced *= manual_diff(x_func, theta)
replaced = replaced.trigsimp()
secants = replaced.find(1/sympy.cos(theta))
if secants:
replaced = replaced.xreplace({
1/sympy.cos(theta): sympy.sec(theta)
})
substep = integral_steps(replaced, theta)
if not contains_dont_know(substep):
return TrigSubstitutionRule(
theta, x_func, replaced, substep, restriction,
integrand, symbol)
def heaviside_rule(integral):
integrand, symbol = integral
pattern, m, b, g = heaviside_pattern(symbol)
match = integrand.match(pattern)
if match and 0 != match[g]:
# f = Heaviside(m*x + b)*g
v_step = integral_steps(match[g], symbol)
result = _manualintegrate(v_step)
m, b = match[m], match[b]
return HeavisideRule(m*symbol + b, -b/m, result, integrand, symbol)
def substitution_rule(integral):
integrand, symbol = integral
u_var = sympy.Dummy("u")
substitutions = find_substitutions(integrand, symbol, u_var)
if substitutions:
ways = []
for u_func, c, substituted in substitutions:
subrule = integral_steps(substituted, u_var)
if contains_dont_know(subrule):
continue
if sympy.simplify(c - 1) != 0:
_, denom = c.as_numer_denom()
if subrule:
subrule = ConstantTimesRule(c, substituted, subrule, substituted, u_var)
if denom.free_symbols:
piecewise = []
could_be_zero = []
if isinstance(denom, sympy.Mul):
could_be_zero = denom.args
else:
could_be_zero.append(denom)
for expr in could_be_zero:
if not fuzzy_not(expr.is_zero):
substep = integral_steps(manual_subs(integrand, expr, 0), symbol)
if substep:
piecewise.append((
substep,
sympy.Eq(expr, 0)
))
piecewise.append((subrule, True))
subrule = PiecewiseRule(piecewise, substituted, symbol)
ways.append(URule(u_var, u_func, c,
subrule,
integrand, symbol))
if len(ways) > 1:
return AlternativeRule(ways, integrand, symbol)
elif ways:
return ways[0]
elif integrand.has(sympy.exp):
u_func = sympy.exp(symbol)
c = 1
substituted = integrand / u_func.diff(symbol)
substituted = substituted.subs(u_func, u_var)
if symbol not in substituted.free_symbols:
return URule(u_var, u_func, c,
integral_steps(substituted, u_var),
integrand, symbol)
partial_fractions_rule = rewriter(
lambda integrand, symbol: integrand.is_rational_function(),
lambda integrand, symbol: integrand.apart(symbol))
cancel_rule = rewriter(
# lambda integrand, symbol: integrand.is_algebraic_expr(),
# lambda integrand, symbol: isinstance(integrand, sympy.Mul),
lambda integrand, symbol: True,
lambda integrand, symbol: integrand.cancel())
distribute_expand_rule = rewriter(
lambda integrand, symbol: (
all(arg.is_Pow or arg.is_polynomial(symbol) for arg in integrand.args)
or isinstance(integrand, sympy.Pow)
or isinstance(integrand, sympy.Mul)),
lambda integrand, symbol: integrand.expand())
trig_expand_rule = rewriter(
# If there are trig functions with different arguments, expand them
lambda integrand, symbol: (
len(set(a.args[0] for a in integrand.atoms(TrigonometricFunction))) > 1),
lambda integrand, symbol: integrand.expand(trig=True))
def derivative_rule(integral):
integrand = integral[0]
diff_variables = integrand.variables
undifferentiated_function = integrand.expr
integrand_variables = undifferentiated_function.free_symbols
if integral.symbol in integrand_variables:
if integral.symbol in diff_variables:
return DerivativeRule(*integral)
else:
return DontKnowRule(integrand, integral.symbol)
else:
return ConstantRule(integral.integrand, *integral)
def rewrites_rule(integral):
integrand, symbol = integral
if integrand.match(1/sympy.cos(symbol)):
rewritten = integrand.subs(1/sympy.cos(symbol), sympy.sec(symbol))
return RewriteRule(rewritten, integral_steps(rewritten, symbol), integrand, symbol)
def fallback_rule(integral):
return DontKnowRule(*integral)
# Cache is used to break cyclic integrals.
# Need to use the same dummy variable in cached expressions for them to match.
# Also record "u" of integration by parts, to avoid infinite repetition.
_integral_cache = {}
_parts_u_cache = defaultdict(int)
_cache_dummy = sympy.Dummy("z")
def integral_steps(integrand, symbol, **options):
"""Returns the steps needed to compute an integral.
This function attempts to mirror what a student would do by hand as
closely as possible.
SymPy Gamma uses this to provide a step-by-step explanation of an
integral. The code it uses to format the results of this function can be
found at
https://github.com/sympy/sympy_gamma/blob/master/app/logic/intsteps.py.
Examples
========
>>> from sympy import exp, sin, cos
>>> from sympy.integrals.manualintegrate import integral_steps
>>> from sympy.abc import x
>>> print(repr(integral_steps(exp(x) / (1 + exp(2 * x)), x))) \
# doctest: +NORMALIZE_WHITESPACE
URule(u_var=_u, u_func=exp(x), constant=1,
substep=PiecewiseRule(subfunctions=[(ArctanRule(a=1, b=1, c=1, context=1/(_u**2 + 1), symbol=_u), True),
(ArccothRule(a=1, b=1, c=1, context=1/(_u**2 + 1), symbol=_u), False),
(ArctanhRule(a=1, b=1, c=1, context=1/(_u**2 + 1), symbol=_u), False)],
context=1/(_u**2 + 1), symbol=_u), context=exp(x)/(exp(2*x) + 1), symbol=x)
>>> print(repr(integral_steps(sin(x), x))) \
# doctest: +NORMALIZE_WHITESPACE
TrigRule(func='sin', arg=x, context=sin(x), symbol=x)
>>> print(repr(integral_steps((x**2 + 3)**2 , x))) \
# doctest: +NORMALIZE_WHITESPACE
RewriteRule(rewritten=x**4 + 6*x**2 + 9,
substep=AddRule(substeps=[PowerRule(base=x, exp=4, context=x**4, symbol=x),
ConstantTimesRule(constant=6, other=x**2,
substep=PowerRule(base=x, exp=2, context=x**2, symbol=x),
context=6*x**2, symbol=x),
ConstantRule(constant=9, context=9, symbol=x)],
context=x**4 + 6*x**2 + 9, symbol=x), context=(x**2 + 3)**2, symbol=x)
Returns
=======
rule : namedtuple
The first step; most rules have substeps that must also be
considered. These substeps can be evaluated using ``manualintegrate``
to obtain a result.
"""
cachekey = integrand.xreplace({symbol: _cache_dummy})
if cachekey in _integral_cache:
if _integral_cache[cachekey] is None:
# Stop this attempt, because it leads around in a loop
return DontKnowRule(integrand, symbol)
else:
# TODO: This is for future development, as currently
# _integral_cache gets no values other than None
return (_integral_cache[cachekey].xreplace(_cache_dummy, symbol),
symbol)
else:
_integral_cache[cachekey] = None
integral = IntegralInfo(integrand, symbol)
def key(integral):
integrand = integral.integrand
if isinstance(integrand, TrigonometricFunction):
return TrigonometricFunction
elif isinstance(integrand, sympy.Derivative):
return sympy.Derivative
elif symbol not in integrand.free_symbols:
return sympy.Number
else:
for cls in (sympy.Pow, sympy.Symbol, sympy.exp, sympy.log,
sympy.Add, sympy.Mul, sympy.atan, sympy.asin,
sympy.acos, sympy.Heaviside, OrthogonalPolynomial):
if isinstance(integrand, cls):
return cls
def integral_is_subclass(*klasses):
def _integral_is_subclass(integral):
k = key(integral)
return k and issubclass(k, klasses)
return _integral_is_subclass
result = do_one(
null_safe(special_function_rule),
null_safe(switch(key, {
sympy.Pow: do_one(null_safe(power_rule), null_safe(inverse_trig_rule), \
null_safe(quadratic_denom_rule)),
sympy.Symbol: power_rule,
sympy.exp: exp_rule,
sympy.Add: add_rule,
sympy.Mul: do_one(null_safe(mul_rule), null_safe(trig_product_rule), \
null_safe(heaviside_rule), null_safe(quadratic_denom_rule), \
null_safe(root_mul_rule)),
sympy.Derivative: derivative_rule,
TrigonometricFunction: trig_rule,
sympy.Heaviside: heaviside_rule,
OrthogonalPolynomial: orthogonal_poly_rule,
sympy.Number: constant_rule
})),
do_one(
null_safe(trig_rule),
null_safe(alternatives(
rewrites_rule,
substitution_rule,
condition(
integral_is_subclass(sympy.Mul, sympy.Pow),
partial_fractions_rule),
condition(
integral_is_subclass(sympy.Mul, sympy.Pow),
cancel_rule),
condition(
integral_is_subclass(sympy.Mul, sympy.log, sympy.atan, sympy.asin, sympy.acos),
parts_rule),
condition(
integral_is_subclass(sympy.Mul, sympy.Pow),
distribute_expand_rule),
trig_powers_products_rule,
trig_expand_rule
)),
null_safe(trig_substitution_rule)
),
fallback_rule)(integral)
del _integral_cache[cachekey]
return result
@evaluates(ConstantRule)
def eval_constant(constant, integrand, symbol):
return constant * symbol
@evaluates(ConstantTimesRule)
def eval_constanttimes(constant, other, substep, integrand, symbol):
return constant * _manualintegrate(substep)
@evaluates(PowerRule)
def eval_power(base, exp, integrand, symbol):
return sympy.Piecewise(
((base**(exp + 1))/(exp + 1), sympy.Ne(exp, -1)),
(sympy.log(base), True),
)
@evaluates(ExpRule)
def eval_exp(base, exp, integrand, symbol):
return integrand / sympy.ln(base)
@evaluates(AddRule)
def eval_add(substeps, integrand, symbol):
return sum(map(_manualintegrate, substeps))
@evaluates(URule)
def eval_u(u_var, u_func, constant, substep, integrand, symbol):
result = _manualintegrate(substep)
if u_func.is_Pow and u_func.exp == -1:
# avoid needless -log(1/x) from substitution
result = result.subs(sympy.log(u_var), -sympy.log(u_func.base))
return result.subs(u_var, u_func)
@evaluates(PartsRule)
def eval_parts(u, dv, v_step, second_step, integrand, symbol):
v = _manualintegrate(v_step)
return u * v - _manualintegrate(second_step)
@evaluates(CyclicPartsRule)
def eval_cyclicparts(parts_rules, coefficient, integrand, symbol):
coefficient = 1 - coefficient
result = []
sign = 1
for rule in parts_rules:
result.append(sign * rule.u * _manualintegrate(rule.v_step))
sign *= -1
return sympy.Add(*result) / coefficient
@evaluates(TrigRule)
def eval_trig(func, arg, integrand, symbol):
if func == 'sin':
return -sympy.cos(arg)
elif func == 'cos':
return sympy.sin(arg)
elif func == 'sec*tan':
return sympy.sec(arg)
elif func == 'csc*cot':
return sympy.csc(arg)
elif func == 'sec**2':
return sympy.tan(arg)
elif func == 'csc**2':
return -sympy.cot(arg)
@evaluates(ArctanRule)
def eval_arctan(a, b, c, integrand, symbol):
return a / b * 1 / sympy.sqrt(c / b) * sympy.atan(symbol / sympy.sqrt(c / b))
@evaluates(ArccothRule)
def eval_arccoth(a, b, c, integrand, symbol):
return - a / b * 1 / sympy.sqrt(-c / b) * sympy.acoth(symbol / sympy.sqrt(-c / b))
@evaluates(ArctanhRule)
def eval_arctanh(a, b, c, integrand, symbol):
return - a / b * 1 / sympy.sqrt(-c / b) * sympy.atanh(symbol / sympy.sqrt(-c / b))
@evaluates(ReciprocalRule)
def eval_reciprocal(func, integrand, symbol):
return sympy.ln(func)
@evaluates(ArcsinRule)
def eval_arcsin(integrand, symbol):
return sympy.asin(symbol)
@evaluates(InverseHyperbolicRule)
def eval_inversehyperbolic(func, integrand, symbol):
return func(symbol)
@evaluates(AlternativeRule)
def eval_alternative(alternatives, integrand, symbol):
return _manualintegrate(alternatives[0])
@evaluates(RewriteRule)
def eval_rewrite(rewritten, substep, integrand, symbol):
return _manualintegrate(substep)
@evaluates(PiecewiseRule)
def eval_piecewise(substeps, integrand, symbol):
return sympy.Piecewise(*[(_manualintegrate(substep), cond)
for substep, cond in substeps])
@evaluates(TrigSubstitutionRule)
def eval_trigsubstitution(theta, func, rewritten, substep, restriction, integrand, symbol):
func = func.subs(sympy.sec(theta), 1/sympy.cos(theta))
trig_function = list(func.find(TrigonometricFunction))
assert len(trig_function) == 1
trig_function = trig_function[0]
relation = sympy.solve(symbol - func, trig_function)
assert len(relation) == 1
numer, denom = sympy.fraction(relation[0])
if isinstance(trig_function, sympy.sin):
opposite = numer
hypotenuse = denom
adjacent = sympy.sqrt(denom**2 - numer**2)
inverse = sympy.asin(relation[0])
elif isinstance(trig_function, sympy.cos):
adjacent = numer
hypotenuse = denom
opposite = sympy.sqrt(denom**2 - numer**2)
inverse = sympy.acos(relation[0])
elif isinstance(trig_function, sympy.tan):
opposite = numer
adjacent = denom
hypotenuse = sympy.sqrt(denom**2 + numer**2)
inverse = sympy.atan(relation[0])
substitution = [
(sympy.sin(theta), opposite/hypotenuse),
(sympy.cos(theta), adjacent/hypotenuse),
(sympy.tan(theta), opposite/adjacent),
(theta, inverse)
]
return sympy.Piecewise(
(_manualintegrate(substep).subs(substitution).trigsimp(), restriction)
)
@evaluates(DerivativeRule)
def eval_derivativerule(integrand, symbol):
# isinstance(integrand, Derivative) should be True
variable_count = list(integrand.variable_count)
for i, (var, count) in enumerate(variable_count):
if var == symbol:
variable_count[i] = (var, count-1)
break
return sympy.Derivative(integrand.expr, *variable_count)
@evaluates(HeavisideRule)
def eval_heaviside(harg, ibnd, substep, integrand, symbol):
# If we are integrating over x and the integrand has the form
# Heaviside(m*x+b)*g(x) == Heaviside(harg)*g(symbol)
# then there needs to be continuity at -b/m == ibnd,
# so we subtract the appropriate term.
return sympy.Heaviside(harg)*(substep - substep.subs(symbol, ibnd))
@evaluates(JacobiRule)
def eval_jacobi(n, a, b, integrand, symbol):
return Piecewise(
(2*sympy.jacobi(n + 1, a - 1, b - 1, symbol)/(n + a + b), Ne(n + a + b, 0)),
(symbol, Eq(n, 0)),
((a + b + 2)*symbol**2/4 + (a - b)*symbol/2, Eq(n, 1)))
@evaluates(GegenbauerRule)
def eval_gegenbauer(n, a, integrand, symbol):
return Piecewise(
(sympy.gegenbauer(n + 1, a - 1, symbol)/(2*(a - 1)), Ne(a, 1)),
(sympy.chebyshevt(n + 1, symbol)/(n + 1), Ne(n, -1)),
(sympy.S.Zero, True))
@evaluates(ChebyshevTRule)
def eval_chebyshevt(n, integrand, symbol):
return Piecewise(((sympy.chebyshevt(n + 1, symbol)/(n + 1) -
sympy.chebyshevt(n - 1, symbol)/(n - 1))/2, Ne(sympy.Abs(n), 1)),
(symbol**2/2, True))
@evaluates(ChebyshevURule)
def eval_chebyshevu(n, integrand, symbol):
return Piecewise(
(sympy.chebyshevt(n + 1, symbol)/(n + 1), Ne(n, -1)),
(sympy.S.Zero, True))
@evaluates(LegendreRule)
def eval_legendre(n, integrand, symbol):
return (sympy.legendre(n + 1, symbol) - sympy.legendre(n - 1, symbol))/(2*n + 1)
@evaluates(HermiteRule)
def eval_hermite(n, integrand, symbol):
return sympy.hermite(n + 1, symbol)/(2*(n + 1))
@evaluates(LaguerreRule)
def eval_laguerre(n, integrand, symbol):
return sympy.laguerre(n, symbol) - sympy.laguerre(n + 1, symbol)
@evaluates(AssocLaguerreRule)
def eval_assoclaguerre(n, a, integrand, symbol):
return -sympy.assoc_laguerre(n + 1, a - 1, symbol)
@evaluates(CiRule)
def eval_ci(a, b, integrand, symbol):
return sympy.cos(b)*sympy.Ci(a*symbol) - sympy.sin(b)*sympy.Si(a*symbol)
@evaluates(ChiRule)
def eval_chi(a, b, integrand, symbol):
return sympy.cosh(b)*sympy.Chi(a*symbol) + sympy.sinh(b)*sympy.Shi(a*symbol)
@evaluates(EiRule)
def eval_ei(a, b, integrand, symbol):
return sympy.exp(b)*sympy.Ei(a*symbol)
@evaluates(SiRule)
def eval_si(a, b, integrand, symbol):
return sympy.sin(b)*sympy.Ci(a*symbol) + sympy.cos(b)*sympy.Si(a*symbol)
@evaluates(ShiRule)
def eval_shi(a, b, integrand, symbol):
return sympy.sinh(b)*sympy.Chi(a*symbol) + sympy.cosh(b)*sympy.Shi(a*symbol)
@evaluates(ErfRule)
def eval_erf(a, b, c, integrand, symbol):
return Piecewise(
(sympy.sqrt(sympy.pi/(-a))/2 * sympy.exp(c - b**2/(4*a)) *
sympy.erf((-2*a*symbol - b)/(2*sympy.sqrt(-a))), a < 0),
(sympy.sqrt(sympy.pi/a)/2 * sympy.exp(c - b**2/(4*a)) *
sympy.erfi((2*a*symbol + b)/(2*sympy.sqrt(a))), True))
@evaluates(FresnelCRule)
def eval_fresnelc(a, b, c, integrand, symbol):
return sympy.sqrt(sympy.pi/(2*a)) * (
sympy.cos(b**2/(4*a) - c)*sympy.fresnelc((2*a*symbol + b)/sympy.sqrt(2*a*sympy.pi)) +
sympy.sin(b**2/(4*a) - c)*sympy.fresnels((2*a*symbol + b)/sympy.sqrt(2*a*sympy.pi)))
@evaluates(FresnelSRule)
def eval_fresnels(a, b, c, integrand, symbol):
return sympy.sqrt(sympy.pi/(2*a)) * (
sympy.cos(b**2/(4*a) - c)*sympy.fresnels((2*a*symbol + b)/sympy.sqrt(2*a*sympy.pi)) -
sympy.sin(b**2/(4*a) - c)*sympy.fresnelc((2*a*symbol + b)/sympy.sqrt(2*a*sympy.pi)))
@evaluates(LiRule)
def eval_li(a, b, integrand, symbol):
return sympy.li(a*symbol + b)/a
@evaluates(PolylogRule)
def eval_polylog(a, b, integrand, symbol):
return sympy.polylog(b + 1, a*symbol)
@evaluates(UpperGammaRule)
def eval_uppergamma(a, e, integrand, symbol):
return symbol**e * (-a*symbol)**(-e) * sympy.uppergamma(e + 1, -a*symbol)/a
@evaluates(EllipticFRule)
def eval_elliptic_f(a, d, integrand, symbol):
return sympy.elliptic_f(symbol, d/a)/sympy.sqrt(a)
@evaluates(EllipticERule)
def eval_elliptic_e(a, d, integrand, symbol):
return sympy.elliptic_e(symbol, d/a)*sympy.sqrt(a)
@evaluates(DontKnowRule)
def eval_dontknowrule(integrand, symbol):
return sympy.Integral(integrand, symbol)
def _manualintegrate(rule):
evaluator = evaluators.get(rule.__class__)
if not evaluator:
raise ValueError("Cannot evaluate rule %s" % repr(rule))
return evaluator(*rule)
def manualintegrate(f, var):
"""manualintegrate(f, var)
Compute indefinite integral of a single variable using an algorithm that
resembles what a student would do by hand.
Unlike ``integrate``, var can only be a single symbol.
Examples
========
>>> from sympy import sin, cos, tan, exp, log, integrate
>>> from sympy.integrals.manualintegrate import manualintegrate
>>> from sympy.abc import x
>>> manualintegrate(1 / x, x)
log(x)
>>> integrate(1/x)
log(x)
>>> manualintegrate(log(x), x)
x*log(x) - x
>>> integrate(log(x))
x*log(x) - x
>>> manualintegrate(exp(x) / (1 + exp(2 * x)), x)
atan(exp(x))
>>> integrate(exp(x) / (1 + exp(2 * x)))
RootSum(4*_z**2 + 1, Lambda(_i, _i*log(2*_i + exp(x))))
>>> manualintegrate(cos(x)**4 * sin(x), x)
-cos(x)**5/5
>>> integrate(cos(x)**4 * sin(x), x)
-cos(x)**5/5
>>> manualintegrate(cos(x)**4 * sin(x)**3, x)
cos(x)**7/7 - cos(x)**5/5
>>> integrate(cos(x)**4 * sin(x)**3, x)
cos(x)**7/7 - cos(x)**5/5
>>> manualintegrate(tan(x), x)
-log(cos(x))
>>> integrate(tan(x), x)
-log(cos(x))
See Also
========
sympy.integrals.integrals.integrate
sympy.integrals.integrals.Integral.doit
sympy.integrals.integrals.Integral
"""
result = _manualintegrate(integral_steps(f, var))
# Clear the cache of u-parts
_parts_u_cache.clear()
# If we got Piecewise with two parts, put generic first
if isinstance(result, Piecewise) and len(result.args) == 2:
cond = result.args[0][1]
if isinstance(cond, Eq) and result.args[1][1] == True:
result = result.func(
(result.args[1][0], sympy.Ne(*cond.args)),
(result.args[0][0], True))
return result
|
36e2eb75d817667e710e1e4162f81560a1d360f2e366cdd82714b6cf25c68319
|
from __future__ import print_function, division
from sympy.concrete.expr_with_limits import AddWithLimits
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.compatibility import is_sequence, range
from sympy.core.containers import Tuple
from sympy.core.expr import Expr
from sympy.core.function import diff
from sympy.core.mul import Mul
from sympy.core.numbers import oo, pi
from sympy.core.relational import Eq, Ne
from sympy.core.singleton import S
from sympy.core.symbol import (Dummy, Symbol, Wild)
from sympy.core.sympify import sympify
from sympy.integrals.manualintegrate import manualintegrate
from sympy.integrals.trigonometry import trigintegrate
from sympy.integrals.meijerint import meijerint_definite, meijerint_indefinite
from sympy.matrices import MatrixBase
from sympy.utilities.misc import filldedent
from sympy.polys import Poly, PolynomialError
from sympy.functions import Piecewise, sqrt, sign, piecewise_fold, tan, cot, atan
from sympy.functions.elementary.exponential import log
from sympy.functions.elementary.integers import floor
from sympy.functions.elementary.complexes import Abs, sign
from sympy.functions.elementary.miscellaneous import Min, Max
from sympy.series import limit
from sympy.series.order import Order
from sympy.series.formal import FormalPowerSeries
from sympy.simplify.fu import sincos_to_sum
class Integral(AddWithLimits):
"""Represents unevaluated integral."""
__slots__ = ['is_commutative']
def __new__(cls, function, *symbols, **assumptions):
"""Create an unevaluated integral.
Arguments are an integrand followed by one or more limits.
If no limits are given and there is only one free symbol in the
expression, that symbol will be used, otherwise an error will be
raised.
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> Integral(x)
Integral(x, x)
>>> Integral(y)
Integral(y, y)
When limits are provided, they are interpreted as follows (using
``x`` as though it were the variable of integration):
(x,) or x - indefinite integral
(x, a) - "evaluate at" integral is an abstract antiderivative
(x, a, b) - definite integral
The ``as_dummy`` method can be used to see which symbols cannot be
targeted by subs: those with a preppended underscore cannot be
changed with ``subs``. (Also, the integration variables themselves --
the first element of a limit -- can never be changed by subs.)
>>> i = Integral(x, x)
>>> at = Integral(x, (x, x))
>>> i.as_dummy()
Integral(x, x)
>>> at.as_dummy()
Integral(_0, (_0, x))
"""
#This will help other classes define their own definitions
#of behaviour with Integral.
if hasattr(function, '_eval_Integral'):
return function._eval_Integral(*symbols, **assumptions)
obj = AddWithLimits.__new__(cls, function, *symbols, **assumptions)
return obj
def __getnewargs__(self):
return (self.function,) + tuple([tuple(xab) for xab in self.limits])
@property
def free_symbols(self):
"""
This method returns the symbols that will exist when the
integral is evaluated. This is useful if one is trying to
determine whether an integral depends on a certain
symbol or not.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> Integral(x, (x, y, 1)).free_symbols
{y}
See Also
========
function, limits, variables
"""
return AddWithLimits.free_symbols.fget(self)
def _eval_is_zero(self):
# This is a very naive and quick test, not intended to do the integral to
# answer whether it is zero or not, e.g. Integral(sin(x), (x, 0, 2*pi))
# is zero but this routine should return None for that case. But, like
# Mul, there are trivial situations for which the integral will be
# zero so we check for those.
if self.function.is_zero:
return True
got_none = False
for l in self.limits:
if len(l) == 3:
z = (l[1] == l[2]) or (l[1] - l[2]).is_zero
if z:
return True
elif z is None:
got_none = True
free = self.function.free_symbols
for xab in self.limits:
if len(xab) == 1:
free.add(xab[0])
continue
if len(xab) == 2 and xab[0] not in free:
if xab[1].is_zero:
return True
elif xab[1].is_zero is None:
got_none = True
# take integration symbol out of free since it will be replaced
# with the free symbols in the limits
free.discard(xab[0])
# add in the new symbols
for i in xab[1:]:
free.update(i.free_symbols)
if self.function.is_zero is False and got_none is False:
return False
def transform(self, x, u):
r"""
Performs a change of variables from `x` to `u` using the relationship
given by `x` and `u` which will define the transformations `f` and `F`
(which are inverses of each other) as follows:
1) If `x` is a Symbol (which is a variable of integration) then `u`
will be interpreted as some function, f(u), with inverse F(u).
This, in effect, just makes the substitution of x with f(x).
2) If `u` is a Symbol then `x` will be interpreted as some function,
F(x), with inverse f(u). This is commonly referred to as
u-substitution.
Once f and F have been identified, the transformation is made as
follows:
.. math:: \int_a^b x \mathrm{d}x \rightarrow \int_{F(a)}^{F(b)} f(x)
\frac{\mathrm{d}}{\mathrm{d}x}
where `F(x)` is the inverse of `f(x)` and the limits and integrand have
been corrected so as to retain the same value after integration.
Notes
=====
The mappings, F(x) or f(u), must lead to a unique integral. Linear
or rational linear expression, `2*x`, `1/x` and `sqrt(x)`, will
always work; quadratic expressions like `x**2 - 1` are acceptable
as long as the resulting integrand does not depend on the sign of
the solutions (see examples).
The integral will be returned unchanged if `x` is not a variable of
integration.
`x` must be (or contain) only one of of the integration variables. If
`u` has more than one free symbol then it should be sent as a tuple
(`u`, `uvar`) where `uvar` identifies which variable is replacing
the integration variable.
XXX can it contain another integration variable?
Examples
========
>>> from sympy.abc import a, b, c, d, x, u, y
>>> from sympy import Integral, S, cos, sqrt
>>> i = Integral(x*cos(x**2 - 1), (x, 0, 1))
transform can change the variable of integration
>>> i.transform(x, u)
Integral(u*cos(u**2 - 1), (u, 0, 1))
transform can perform u-substitution as long as a unique
integrand is obtained:
>>> i.transform(x**2 - 1, u)
Integral(cos(u)/2, (u, -1, 0))
This attempt fails because x = +/-sqrt(u + 1) and the
sign does not cancel out of the integrand:
>>> Integral(cos(x**2 - 1), (x, 0, 1)).transform(x**2 - 1, u)
Traceback (most recent call last):
...
ValueError:
The mapping between F(x) and f(u) did not give a unique integrand.
transform can do a substitution. Here, the previous
result is transformed back into the original expression
using "u-substitution":
>>> ui = _
>>> _.transform(sqrt(u + 1), x) == i
True
We can accomplish the same with a regular substitution:
>>> ui.transform(u, x**2 - 1) == i
True
If the `x` does not contain a symbol of integration then
the integral will be returned unchanged. Integral `i` does
not have an integration variable `a` so no change is made:
>>> i.transform(a, x) == i
True
When `u` has more than one free symbol the symbol that is
replacing `x` must be identified by passing `u` as a tuple:
>>> Integral(x, (x, 0, 1)).transform(x, (u + a, u))
Integral(a + u, (u, -a, -a + 1))
>>> Integral(x, (x, 0, 1)).transform(x, (u + a, a))
Integral(a + u, (a, -u, -u + 1))
See Also
========
variables : Lists the integration variables
as_dummy : Replace integration variables with dummy ones
"""
from sympy.solvers.solvers import solve, posify
d = Dummy('d')
xfree = x.free_symbols.intersection(self.variables)
if len(xfree) > 1:
raise ValueError(
'F(x) can only contain one of: %s' % self.variables)
xvar = xfree.pop() if xfree else d
if xvar not in self.variables:
return self
u = sympify(u)
if isinstance(u, Expr):
ufree = u.free_symbols
if len(ufree) != 1:
raise ValueError(filldedent('''
When f(u) has more than one free symbol, the one replacing x
must be identified: pass f(u) as (f(u), u)'''))
uvar = ufree.pop()
else:
u, uvar = u
if uvar not in u.free_symbols:
raise ValueError(filldedent('''
Expecting a tuple (expr, symbol) where symbol identified
a free symbol in expr, but symbol is not in expr's free
symbols.'''))
if not isinstance(uvar, Symbol):
raise ValueError(filldedent('''
Expecting a tuple (expr, symbol) but didn't get
a symbol; got %s''' % uvar))
if x.is_Symbol and u.is_Symbol:
return self.xreplace({x: u})
if not x.is_Symbol and not u.is_Symbol:
raise ValueError('either x or u must be a symbol')
if uvar == xvar:
return self.transform(x, (u.subs(uvar, d), d)).xreplace({d: uvar})
if uvar in self.limits:
raise ValueError(filldedent('''
u must contain the same variable as in x
or a variable that is not already an integration variable'''))
if not x.is_Symbol:
F = [x.subs(xvar, d)]
soln = solve(u - x, xvar, check=False)
if not soln:
raise ValueError('no solution for solve(F(x) - f(u), x)')
f = [fi.subs(uvar, d) for fi in soln]
else:
f = [u.subs(uvar, d)]
pdiff, reps = posify(u - x)
puvar = uvar.subs([(v, k) for k, v in reps.items()])
soln = [s.subs(reps) for s in solve(pdiff, puvar)]
if not soln:
raise ValueError('no solution for solve(F(x) - f(u), u)')
F = [fi.subs(xvar, d) for fi in soln]
newfuncs = set([(self.function.subs(xvar, fi)*fi.diff(d)
).subs(d, uvar) for fi in f])
if len(newfuncs) > 1:
raise ValueError(filldedent('''
The mapping between F(x) and f(u) did not give
a unique integrand.'''))
newfunc = newfuncs.pop()
def _calc_limit_1(F, a, b):
"""
replace d with a, using subs if possible, otherwise limit
where sign of b is considered
"""
wok = F.subs(d, a)
if wok is S.NaN or wok.is_finite is False and a.is_finite:
return limit(sign(b)*F, d, a)
return wok
def _calc_limit(a, b):
"""
replace d with a, using subs if possible, otherwise limit
where sign of b is considered
"""
avals = list({_calc_limit_1(Fi, a, b) for Fi in F})
if len(avals) > 1:
raise ValueError(filldedent('''
The mapping between F(x) and f(u) did not
give a unique limit.'''))
return avals[0]
newlimits = []
for xab in self.limits:
sym = xab[0]
if sym == xvar:
if len(xab) == 3:
a, b = xab[1:]
a, b = _calc_limit(a, b), _calc_limit(b, a)
if a - b > 0:
a, b = b, a
newfunc = -newfunc
newlimits.append((uvar, a, b))
elif len(xab) == 2:
a = _calc_limit(xab[1], 1)
newlimits.append((uvar, a))
else:
newlimits.append(uvar)
else:
newlimits.append(xab)
return self.func(newfunc, *newlimits)
def doit(self, **hints):
"""
Perform the integration using any hints given.
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, i
>>> Integral(x**i, (i, 1, 3)).doit()
Piecewise((x**3/log(x) - x/log(x),
(x > 1) | ((x >= 0) & (x < 1))), (2, True))
See Also
========
sympy.integrals.trigonometry.trigintegrate
sympy.integrals.risch.heurisch
sympy.integrals.rationaltools.ratint
as_sum : Approximate the integral using a sum
"""
if not hints.get('integrals', True):
return self
deep = hints.get('deep', True)
meijerg = hints.get('meijerg', None)
conds = hints.get('conds', 'piecewise')
risch = hints.get('risch', None)
heurisch = hints.get('heurisch', None)
manual = hints.get('manual', None)
if len(list(filter(None, (manual, meijerg, risch, heurisch)))) > 1:
raise ValueError("At most one of manual, meijerg, risch, heurisch can be True")
elif manual:
meijerg = risch = heurisch = False
elif meijerg:
manual = risch = heurisch = False
elif risch:
manual = meijerg = heurisch = False
elif heurisch:
manual = meijerg = risch = False
eval_kwargs = dict(meijerg=meijerg, risch=risch, manual=manual, heurisch=heurisch,
conds=conds)
if conds not in ['separate', 'piecewise', 'none']:
raise ValueError('conds must be one of "separate", "piecewise", '
'"none", got: %s' % conds)
if risch and any(len(xab) > 1 for xab in self.limits):
raise ValueError('risch=True is only allowed for indefinite integrals.')
# check for the trivial zero
if self.is_zero:
return S.Zero
# now compute and check the function
function = self.function
if deep:
function = function.doit(**hints)
if function.is_zero:
return S.Zero
# hacks to handle special cases
if isinstance(function, MatrixBase):
return function.applyfunc(
lambda f: self.func(f, self.limits).doit(**hints))
if isinstance(function, FormalPowerSeries):
if len(self.limits) > 1:
raise NotImplementedError
xab = self.limits[0]
if len(xab) > 1:
return function.integrate(xab, **eval_kwargs)
else:
return function.integrate(xab[0], **eval_kwargs)
# There is no trivial answer and special handling
# is done so continue
undone_limits = []
# ulj = free symbols of any undone limits' upper and lower limits
ulj = set()
for xab in self.limits:
# compute uli, the free symbols in the
# Upper and Lower limits of limit I
if len(xab) == 1:
uli = set(xab[:1])
elif len(xab) == 2:
uli = xab[1].free_symbols
elif len(xab) == 3:
uli = xab[1].free_symbols.union(xab[2].free_symbols)
# this integral can be done as long as there is no blocking
# limit that has been undone. An undone limit is blocking if
# it contains an integration variable that is in this limit's
# upper or lower free symbols or vice versa
if xab[0] in ulj or any(v[0] in uli for v in undone_limits):
undone_limits.append(xab)
ulj.update(uli)
function = self.func(*([function] + [xab]))
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
continue
if function.has(Abs, sign) and (
(len(xab) < 3 and all(x.is_real for x in xab)) or
(len(xab) == 3 and all(x.is_real and not x.is_infinite for
x in xab[1:]))):
# some improper integrals are better off with Abs
xr = Dummy("xr", real=True)
function = (function.xreplace({xab[0]: xr})
.rewrite(Piecewise).xreplace({xr: xab[0]}))
elif function.has(Min, Max):
function = function.rewrite(Piecewise)
if (function.has(Piecewise) and
not isinstance(function, Piecewise)):
function = piecewise_fold(function)
if isinstance(function, Piecewise):
if len(xab) == 1:
antideriv = function._eval_integral(xab[0],
**eval_kwargs)
else:
antideriv = self._eval_integral(
function, xab[0], **eval_kwargs)
else:
# There are a number of tradeoffs in using the
# Meijer G method. It can sometimes be a lot faster
# than other methods, and sometimes slower. And
# there are certain types of integrals for which it
# is more likely to work than others. These
# heuristics are incorporated in deciding what
# integration methods to try, in what order. See the
# integrate() docstring for details.
def try_meijerg(function, xab):
ret = None
if len(xab) == 3 and meijerg is not False:
x, a, b = xab
try:
res = meijerint_definite(function, x, a, b)
except NotImplementedError:
from sympy.integrals.meijerint import _debug
_debug('NotImplementedError '
'from meijerint_definite')
res = None
if res is not None:
f, cond = res
if conds == 'piecewise':
ret = Piecewise(
(f, cond),
(self.func(
function, (x, a, b)), True))
elif conds == 'separate':
if len(self.limits) != 1:
raise ValueError(filldedent('''
conds=separate not supported in
multiple integrals'''))
ret = f, cond
else:
ret = f
return ret
meijerg1 = meijerg
if (meijerg is not False and
len(xab) == 3 and xab[1].is_real and xab[2].is_real
and not function.is_Poly and
(xab[1].has(oo, -oo) or xab[2].has(oo, -oo))):
ret = try_meijerg(function, xab)
if ret is not None:
function = ret
continue
meijerg1 = False
# If the special meijerg code did not succeed in
# finding a definite integral, then the code using
# meijerint_indefinite will not either (it might
# find an antiderivative, but the answer is likely
# to be nonsensical). Thus if we are requested to
# only use Meijer G-function methods, we give up at
# this stage. Otherwise we just disable G-function
# methods.
if meijerg1 is False and meijerg is True:
antideriv = None
else:
antideriv = self._eval_integral(
function, xab[0], **eval_kwargs)
if antideriv is None and meijerg is True:
ret = try_meijerg(function, xab)
if ret is not None:
function = ret
continue
if not isinstance(antideriv, Integral) and antideriv is not None:
sym = xab[0]
for atan_term in antideriv.atoms(atan):
atan_arg = atan_term.args[0]
# Checking `atan_arg` to be linear combination of `tan` or `cot`
for tan_part in atan_arg.atoms(tan):
x1 = Dummy('x1')
tan_exp1 = atan_arg.subs(tan_part, x1)
# The coefficient of `tan` should be constant
coeff = tan_exp1.diff(x1)
if x1 not in coeff.free_symbols:
a = tan_part.args[0]
antideriv = antideriv.subs(atan_term, Add(atan_term,
sign(coeff)*pi*floor((a-pi/2)/pi)))
for cot_part in atan_arg.atoms(cot):
x1 = Dummy('x1')
cot_exp1 = atan_arg.subs(cot_part, x1)
# The coefficient of `cot` should be constant
coeff = cot_exp1.diff(x1)
if x1 not in coeff.free_symbols:
a = cot_part.args[0]
antideriv = antideriv.subs(atan_term, Add(atan_term,
sign(coeff)*pi*floor((a)/pi)))
if antideriv is None:
undone_limits.append(xab)
function = self.func(*([function] + [xab])).factor()
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
continue
else:
if len(xab) == 1:
function = antideriv
else:
if len(xab) == 3:
x, a, b = xab
elif len(xab) == 2:
x, b = xab
a = None
else:
raise NotImplementedError
if deep:
if isinstance(a, Basic):
a = a.doit(**hints)
if isinstance(b, Basic):
b = b.doit(**hints)
if antideriv.is_Poly:
gens = list(antideriv.gens)
gens.remove(x)
antideriv = antideriv.as_expr()
function = antideriv._eval_interval(x, a, b)
function = Poly(function, *gens)
else:
def is_indef_int(g, x):
return (isinstance(g, Integral) and
any(i == (x,) for i in g.limits))
def eval_factored(f, x, a, b):
# _eval_interval for integrals with
# (constant) factors
# a single indefinite integral is assumed
args = []
for g in Mul.make_args(f):
if is_indef_int(g, x):
args.append(g._eval_interval(x, a, b))
else:
args.append(g)
return Mul(*args)
integrals, others, piecewises = [], [], []
for f in Add.make_args(antideriv):
if any(is_indef_int(g, x)
for g in Mul.make_args(f)):
integrals.append(f)
elif any(isinstance(g, Piecewise)
for g in Mul.make_args(f)):
piecewises.append(piecewise_fold(f))
else:
others.append(f)
uneval = Add(*[eval_factored(f, x, a, b)
for f in integrals])
try:
evalued = Add(*others)._eval_interval(x, a, b)
evalued_pw = piecewise_fold(Add(*piecewises))._eval_interval(x, a, b)
function = uneval + evalued + evalued_pw
except NotImplementedError:
# This can happen if _eval_interval depends in a
# complicated way on limits that cannot be computed
undone_limits.append(xab)
function = self.func(*([function] + [xab]))
factored_function = function.factor()
if not isinstance(factored_function, Integral):
function = factored_function
return function
def _eval_derivative(self, sym):
"""Evaluate the derivative of the current Integral object by
differentiating under the integral sign [1], using the Fundamental
Theorem of Calculus [2] when possible.
Whenever an Integral is encountered that is equivalent to zero or
has an integrand that is independent of the variable of integration
those integrals are performed. All others are returned as Integral
instances which can be resolved with doit() (provided they are integrable).
References:
[1] https://en.wikipedia.org/wiki/Differentiation_under_the_integral_sign
[2] https://en.wikipedia.org/wiki/Fundamental_theorem_of_calculus
Examples
========
>>> from sympy import Integral
>>> from sympy.abc import x, y
>>> i = Integral(x + y, y, (y, 1, x))
>>> i.diff(x)
Integral(x + y, (y, x)) + Integral(1, y, (y, 1, x))
>>> i.doit().diff(x) == i.diff(x).doit()
True
>>> i.diff(y)
0
The previous must be true since there is no y in the evaluated integral:
>>> i.free_symbols
{x}
>>> i.doit()
2*x**3/3 - x/2 - 1/6
"""
# differentiate under the integral sign; we do not
# check for regularity conditions (TODO), see issue 4215
# get limits and the function
f, limits = self.function, list(self.limits)
# the order matters if variables of integration appear in the limits
# so work our way in from the outside to the inside.
limit = limits.pop(-1)
if len(limit) == 3:
x, a, b = limit
elif len(limit) == 2:
x, b = limit
a = None
else:
a = b = None
x = limit[0]
if limits: # f is the argument to an integral
f = self.func(f, *tuple(limits))
# assemble the pieces
def _do(f, ab):
dab_dsym = diff(ab, sym)
if not dab_dsym:
return S.Zero
if isinstance(f, Integral):
limits = [(x, x) if (len(l) == 1 and l[0] == x) else l
for l in f.limits]
f = self.func(f.function, *limits)
return f.subs(x, ab)*dab_dsym
rv = S.Zero
if b is not None:
rv += _do(f, b)
if a is not None:
rv -= _do(f, a)
if len(limit) == 1 and sym == x:
# the dummy variable *is* also the real-world variable
arg = f
rv += arg
else:
# the dummy variable might match sym but it's
# only a dummy and the actual variable is determined
# by the limits, so mask off the variable of integration
# while differentiating
u = Dummy('u')
arg = f.subs(x, u).diff(sym).subs(u, x)
if arg:
rv += self.func(arg, Tuple(x, a, b))
return rv
def _eval_integral(self, f, x, meijerg=None, risch=None, manual=None,
heurisch=None, conds='piecewise'):
"""
Calculate the anti-derivative to the function f(x).
The following algorithms are applied (roughly in this order):
1. Simple heuristics (based on pattern matching and integral table):
- most frequently used functions (e.g. polynomials, products of
trig functions)
2. Integration of rational functions:
- A complete algorithm for integrating rational functions is
implemented (the Lazard-Rioboo-Trager algorithm). The algorithm
also uses the partial fraction decomposition algorithm
implemented in apart() as a preprocessor to make this process
faster. Note that the integral of a rational function is always
elementary, but in general, it may include a RootSum.
3. Full Risch algorithm:
- The Risch algorithm is a complete decision
procedure for integrating elementary functions, which means that
given any elementary function, it will either compute an
elementary antiderivative, or else prove that none exists.
Currently, part of transcendental case is implemented, meaning
elementary integrals containing exponentials, logarithms, and
(soon!) trigonometric functions can be computed. The algebraic
case, e.g., functions containing roots, is much more difficult
and is not implemented yet.
- If the routine fails (because the integrand is not elementary, or
because a case is not implemented yet), it continues on to the
next algorithms below. If the routine proves that the integrals
is nonelementary, it still moves on to the algorithms below,
because we might be able to find a closed-form solution in terms
of special functions. If risch=True, however, it will stop here.
4. The Meijer G-Function algorithm:
- This algorithm works by first rewriting the integrand in terms of
very general Meijer G-Function (meijerg in SymPy), integrating
it, and then rewriting the result back, if possible. This
algorithm is particularly powerful for definite integrals (which
is actually part of a different method of Integral), since it can
compute closed-form solutions of definite integrals even when no
closed-form indefinite integral exists. But it also is capable
of computing many indefinite integrals as well.
- Another advantage of this method is that it can use some results
about the Meijer G-Function to give a result in terms of a
Piecewise expression, which allows to express conditionally
convergent integrals.
- Setting meijerg=True will cause integrate() to use only this
method.
5. The "manual integration" algorithm:
- This algorithm tries to mimic how a person would find an
antiderivative by hand, for example by looking for a
substitution or applying integration by parts. This algorithm
does not handle as many integrands but can return results in a
more familiar form.
- Sometimes this algorithm can evaluate parts of an integral; in
this case integrate() will try to evaluate the rest of the
integrand using the other methods here.
- Setting manual=True will cause integrate() to use only this
method.
6. The Heuristic Risch algorithm:
- This is a heuristic version of the Risch algorithm, meaning that
it is not deterministic. This is tried as a last resort because
it can be very slow. It is still used because not enough of the
full Risch algorithm is implemented, so that there are still some
integrals that can only be computed using this method. The goal
is to implement enough of the Risch and Meijer G-function methods
so that this can be deleted.
Setting heurisch=True will cause integrate() to use only this
method. Set heurisch=False to not use it.
"""
from sympy.integrals.deltafunctions import deltaintegrate
from sympy.integrals.singularityfunctions import singularityintegrate
from sympy.integrals.heurisch import heurisch as heurisch_, heurisch_wrapper
from sympy.integrals.rationaltools import ratint
from sympy.integrals.risch import risch_integrate
if risch:
try:
return risch_integrate(f, x, conds=conds)
except NotImplementedError:
return None
if manual:
try:
result = manualintegrate(f, x)
if result is not None and result.func != Integral:
return result
except (ValueError, PolynomialError):
pass
eval_kwargs = dict(meijerg=meijerg, risch=risch, manual=manual,
heurisch=heurisch, conds=conds)
# if it is a poly(x) then let the polynomial integrate itself (fast)
#
# It is important to make this check first, otherwise the other code
# will return a sympy expression instead of a Polynomial.
#
# see Polynomial for details.
if isinstance(f, Poly) and not (manual or meijerg or risch):
return f.integrate(x)
# Piecewise antiderivatives need to call special integrate.
if isinstance(f, Piecewise):
return f.piecewise_integrate(x, **eval_kwargs)
# let's cut it short if `f` does not depend on `x`; if
# x is only a dummy, that will be handled below
if not f.has(x):
return f*x
# try to convert to poly(x) and then integrate if successful (fast)
poly = f.as_poly(x)
if poly is not None and not (manual or meijerg or risch):
return poly.integrate().as_expr()
if risch is not False:
try:
result, i = risch_integrate(f, x, separate_integral=True,
conds=conds)
except NotImplementedError:
pass
else:
if i:
# There was a nonelementary integral. Try integrating it.
# if no part of the NonElementaryIntegral is integrated by
# the Risch algorithm, then use the original function to
# integrate, instead of re-written one
if result == 0:
from sympy.integrals.risch import NonElementaryIntegral
return NonElementaryIntegral(f, x).doit(risch=False)
else:
return result + i.doit(risch=False)
else:
return result
# since Integral(f=g1+g2+...) == Integral(g1) + Integral(g2) + ...
# we are going to handle Add terms separately,
# if `f` is not Add -- we only have one term
# Note that in general, this is a bad idea, because Integral(g1) +
# Integral(g2) might not be computable, even if Integral(g1 + g2) is.
# For example, Integral(x**x + x**x*log(x)). But many heuristics only
# work term-wise. So we compute this step last, after trying
# risch_integrate. We also try risch_integrate again in this loop,
# because maybe the integral is a sum of an elementary part and a
# nonelementary part (like erf(x) + exp(x)). risch_integrate() is
# quite fast, so this is acceptable.
parts = []
args = Add.make_args(f)
for g in args:
coeff, g = g.as_independent(x)
# g(x) = const
if g is S.One and not meijerg:
parts.append(coeff*x)
continue
# g(x) = expr + O(x**n)
order_term = g.getO()
if order_term is not None:
h = self._eval_integral(g.removeO(), x, **eval_kwargs)
if h is not None:
h_order_expr = self._eval_integral(order_term.expr, x, **eval_kwargs)
if h_order_expr is not None:
h_order_term = order_term.func(
h_order_expr, *order_term.variables)
parts.append(coeff*(h + h_order_term))
continue
# NOTE: if there is O(x**n) and we fail to integrate then
# there is no point in trying other methods because they
# will fail, too.
return None
# c
# g(x) = (a*x+b)
if g.is_Pow and not g.exp.has(x) and not meijerg:
a = Wild('a', exclude=[x])
b = Wild('b', exclude=[x])
M = g.base.match(a*x + b)
if M is not None:
if g.exp == -1:
h = log(g.base)
elif conds != 'piecewise':
h = g.base**(g.exp + 1) / (g.exp + 1)
else:
h1 = log(g.base)
h2 = g.base**(g.exp + 1) / (g.exp + 1)
h = Piecewise((h2, Ne(g.exp, -1)), (h1, True))
parts.append(coeff * h / M[a])
continue
# poly(x)
# g(x) = -------
# poly(x)
if g.is_rational_function(x) and not (manual or meijerg or risch):
parts.append(coeff * ratint(g, x))
continue
if not (manual or meijerg or risch):
# g(x) = Mul(trig)
h = trigintegrate(g, x, conds=conds)
if h is not None:
parts.append(coeff * h)
continue
# g(x) has at least a DiracDelta term
h = deltaintegrate(g, x)
if h is not None:
parts.append(coeff * h)
continue
# g(x) has at least a Singularity Function term
h = singularityintegrate(g, x)
if h is not None:
parts.append(coeff * h)
continue
# Try risch again.
if risch is not False:
try:
h, i = risch_integrate(g, x,
separate_integral=True, conds=conds)
except NotImplementedError:
h = None
else:
if i:
h = h + i.doit(risch=False)
parts.append(coeff*h)
continue
# fall back to heurisch
if heurisch is not False:
try:
if conds == 'piecewise':
h = heurisch_wrapper(g, x, hints=[])
else:
h = heurisch_(g, x, hints=[])
except PolynomialError:
# XXX: this exception means there is a bug in the
# implementation of heuristic Risch integration
# algorithm.
h = None
else:
h = None
if meijerg is not False and h is None:
# rewrite using G functions
try:
h = meijerint_indefinite(g, x)
except NotImplementedError:
from sympy.integrals.meijerint import _debug
_debug('NotImplementedError from meijerint_definite')
res = None
if h is not None:
parts.append(coeff * h)
continue
if h is None and manual is not False:
try:
result = manualintegrate(g, x)
if result is not None and not isinstance(result, Integral):
if result.has(Integral) and not manual:
# Try to have other algorithms do the integrals
# manualintegrate can't handle,
# unless we were asked to use manual only.
# Keep the rest of eval_kwargs in case another
# method was set to False already
new_eval_kwargs = eval_kwargs
new_eval_kwargs["manual"] = False
result = result.func(*[
arg.doit(**new_eval_kwargs) if
arg.has(Integral) else arg
for arg in result.args
]).expand(multinomial=False,
log=False,
power_exp=False,
power_base=False)
if not result.has(Integral):
parts.append(coeff * result)
continue
except (ValueError, PolynomialError):
# can't handle some SymPy expressions
pass
# if we failed maybe it was because we had
# a product that could have been expanded,
# so let's try an expansion of the whole
# thing before giving up; we don't try this
# at the outset because there are things
# that cannot be solved unless they are
# NOT expanded e.g., x**x*(1+log(x)). There
# should probably be a checker somewhere in this
# routine to look for such cases and try to do
# collection on the expressions if they are already
# in an expanded form
if not h and len(args) == 1:
f = sincos_to_sum(f).expand(mul=True, deep=False)
if f.is_Add:
# Note: risch will be identical on the expanded
# expression, but maybe it will be able to pick out parts,
# like x*(exp(x) + erf(x)).
return self._eval_integral(f, x, **eval_kwargs)
if h is not None:
parts.append(coeff * h)
else:
return None
return Add(*parts)
def _eval_lseries(self, x, logx):
expr = self.as_dummy()
symb = x
for l in expr.limits:
if x in l[1:]:
symb = l[0]
break
for term in expr.function.lseries(symb, logx):
yield integrate(term, *expr.limits)
def _eval_nseries(self, x, n, logx):
expr = self.as_dummy()
symb = x
for l in expr.limits:
if x in l[1:]:
symb = l[0]
break
terms, order = expr.function.nseries(
x=symb, n=n, logx=logx).as_coeff_add(Order)
order = [o.subs(symb, x) for o in order]
return integrate(terms, *expr.limits) + Add(*order)*x
def _eval_as_leading_term(self, x):
series_gen = self.args[0].lseries(x)
for leading_term in series_gen:
if leading_term != 0:
break
return integrate(leading_term, *self.args[1:])
def as_sum(self, n=None, method="midpoint", evaluate=True):
"""
Approximates a definite integral by a sum.
Arguments
---------
n
The number of subintervals to use, optional.
method
One of: 'left', 'right', 'midpoint', 'trapezoid'.
evaluate
If False, returns an unevaluated Sum expression. The default
is True, evaluate the sum.
These methods of approximate integration are described in [1].
[1] https://en.wikipedia.org/wiki/Riemann_sum#Methods
Examples
========
>>> from sympy import sin, sqrt
>>> from sympy.abc import x, n
>>> from sympy.integrals import Integral
>>> e = Integral(sin(x), (x, 3, 7))
>>> e
Integral(sin(x), (x, 3, 7))
For demonstration purposes, this interval will only be split into 2
regions, bounded by [3, 5] and [5, 7].
The left-hand rule uses function evaluations at the left of each
interval:
>>> e.as_sum(2, 'left')
2*sin(5) + 2*sin(3)
The midpoint rule uses evaluations at the center of each interval:
>>> e.as_sum(2, 'midpoint')
2*sin(4) + 2*sin(6)
The right-hand rule uses function evaluations at the right of each
interval:
>>> e.as_sum(2, 'right')
2*sin(5) + 2*sin(7)
The trapezoid rule uses function evaluations on both sides of the
intervals. This is equivalent to taking the average of the left and
right hand rule results:
>>> e.as_sum(2, 'trapezoid')
2*sin(5) + sin(3) + sin(7)
>>> (e.as_sum(2, 'left') + e.as_sum(2, 'right'))/2 == _
True
Here, the discontinuity at x = 0 can be avoided by using the
midpoint or right-hand method:
>>> e = Integral(1/sqrt(x), (x, 0, 1))
>>> e.as_sum(5).n(4)
1.730
>>> e.as_sum(10).n(4)
1.809
>>> e.doit().n(4) # the actual value is 2
2.000
The left- or trapezoid method will encounter the discontinuity and
return infinity:
>>> e.as_sum(5, 'left')
zoo
The number of intervals can be symbolic. If omitted, a dummy symbol
will be used for it.
>>> e = Integral(x**2, (x, 0, 2))
>>> e.as_sum(n, 'right').expand()
8/3 + 4/n + 4/(3*n**2)
This shows that the midpoint rule is more accurate, as its error
term decays as the square of n:
>>> e.as_sum(method='midpoint').expand()
8/3 - 2/(3*_n**2)
A symbolic sum is returned with evaluate=False:
>>> e.as_sum(n, 'midpoint', evaluate=False)
2*Sum((2*_k/n - 1/n)**2, (_k, 1, n))/n
See Also
========
Integral.doit : Perform the integration using any hints
"""
from sympy.concrete.summations import Sum
limits = self.limits
if len(limits) > 1:
raise NotImplementedError(
"Multidimensional midpoint rule not implemented yet")
else:
limit = limits[0]
if (len(limit) != 3 or limit[1].is_finite is False or
limit[2].is_finite is False):
raise ValueError("Expecting a definite integral over "
"a finite interval.")
if n is None:
n = Dummy('n', integer=True, positive=True)
else:
n = sympify(n)
if (n.is_positive is False or n.is_integer is False or
n.is_finite is False):
raise ValueError("n must be a positive integer, got %s" % n)
x, a, b = limit
dx = (b - a)/n
k = Dummy('k', integer=True, positive=True)
f = self.function
if method == "left":
result = dx*Sum(f.subs(x, a + (k-1)*dx), (k, 1, n))
elif method == "right":
result = dx*Sum(f.subs(x, a + k*dx), (k, 1, n))
elif method == "midpoint":
result = dx*Sum(f.subs(x, a + k*dx - dx/2), (k, 1, n))
elif method == "trapezoid":
result = dx*((f.subs(x, a) + f.subs(x, b))/2 +
Sum(f.subs(x, a + k*dx), (k, 1, n - 1)))
else:
raise ValueError("Unknown method %s" % method)
return result.doit() if evaluate else result
def _sage_(self):
import sage.all as sage
f, limits = self.function._sage_(), list(self.limits)
for limit in limits:
if len(limit) == 1:
x = limit[0]
f = sage.integral(f,
x._sage_(),
hold=True)
elif len(limit) == 2:
x, b = limit
f = sage.integral(f,
x._sage_(),
b._sage_(),
hold=True)
else:
x, a, b = limit
f = sage.integral(f,
(x._sage_(),
a._sage_(),
b._sage_()),
hold=True)
return f
def principal_value(self, **kwargs):
"""
Compute the Cauchy Principal Value of the definite integral of a real function in the given interval
on the real axis.
In mathematics, the Cauchy principal value, is a method for assigning values to certain improper
integrals which would otherwise be undefined.
Examples
========
>>> from sympy import Dummy, symbols, integrate, limit, oo
>>> from sympy.integrals.integrals import Integral
>>> from sympy.calculus.singularities import singularities
>>> x = symbols('x')
>>> Integral(x+1, (x, -oo, oo)).principal_value()
oo
>>> f = 1 / (x**3)
>>> Integral(f, (x, -oo, oo)).principal_value()
0
>>> Integral(f, (x, -10, 10)).principal_value()
0
>>> Integral(f, (x, -10, oo)).principal_value() + Integral(f, (x, -oo, 10)).principal_value()
0
References
==========
.. [1] https://en.wikipedia.org/wiki/Cauchy_principal_value
.. [2] http://mathworld.wolfram.com/CauchyPrincipalValue.html
"""
from sympy.calculus import singularities
if len(self.limits) != 1 or len(list(self.limits[0])) != 3:
raise ValueError("You need to insert a variable, lower_limit, and upper_limit correctly to calculate "
"cauchy's principal value")
x, a, b = self.limits[0]
if not (a.is_comparable and b.is_comparable and a <= b):
raise ValueError("The lower_limit must be smaller than or equal to the upper_limit to calculate "
"cauchy's principal value. Also, a and b need to be comparable.")
if a == b:
return 0
r = Dummy('r')
f = self.function
singularities_list = [s for s in singularities(f, x) if s.is_comparable and a <= s <= b]
for i in singularities_list:
if (i == b) or (i == a):
raise ValueError(
'The principal value is not defined in the given interval due to singularity at %d.' % (i))
F = integrate(f, x, **kwargs)
if F.has(Integral):
return self
if a is -oo and b is oo:
I = limit(F - F.subs(x, -x), x, oo)
else:
I = limit(F, x, b, '-') - limit(F, x, a, '+')
for s in singularities_list:
I += limit(((F.subs(x, s - r)) - F.subs(x, s + r)), r, 0, '+')
return I
def integrate(*args, **kwargs):
"""integrate(f, var, ...)
Compute definite or indefinite integral of one or more variables
using Risch-Norman algorithm and table lookup. This procedure is
able to handle elementary algebraic and transcendental functions
and also a huge class of special functions, including Airy,
Bessel, Whittaker and Lambert.
var can be:
- a symbol -- indefinite integration
- a tuple (symbol, a) -- indefinite integration with result
given with `a` replacing `symbol`
- a tuple (symbol, a, b) -- definite integration
Several variables can be specified, in which case the result is
multiple integration. (If var is omitted and the integrand is
univariate, the indefinite integral in that variable will be performed.)
Indefinite integrals are returned without terms that are independent
of the integration variables. (see examples)
Definite improper integrals often entail delicate convergence
conditions. Pass conds='piecewise', 'separate' or 'none' to have
these returned, respectively, as a Piecewise function, as a separate
result (i.e. result will be a tuple), or not at all (default is
'piecewise').
**Strategy**
SymPy uses various approaches to definite integration. One method is to
find an antiderivative for the integrand, and then use the fundamental
theorem of calculus. Various functions are implemented to integrate
polynomial, rational and trigonometric functions, and integrands
containing DiracDelta terms.
SymPy also implements the part of the Risch algorithm, which is a decision
procedure for integrating elementary functions, i.e., the algorithm can
either find an elementary antiderivative, or prove that one does not
exist. There is also a (very successful, albeit somewhat slow) general
implementation of the heuristic Risch algorithm. This algorithm will
eventually be phased out as more of the full Risch algorithm is
implemented. See the docstring of Integral._eval_integral() for more
details on computing the antiderivative using algebraic methods.
The option risch=True can be used to use only the (full) Risch algorithm.
This is useful if you want to know if an elementary function has an
elementary antiderivative. If the indefinite Integral returned by this
function is an instance of NonElementaryIntegral, that means that the
Risch algorithm has proven that integral to be non-elementary. Note that
by default, additional methods (such as the Meijer G method outlined
below) are tried on these integrals, as they may be expressible in terms
of special functions, so if you only care about elementary answers, use
risch=True. Also note that an unevaluated Integral returned by this
function is not necessarily a NonElementaryIntegral, even with risch=True,
as it may just be an indication that the particular part of the Risch
algorithm needed to integrate that function is not yet implemented.
Another family of strategies comes from re-writing the integrand in
terms of so-called Meijer G-functions. Indefinite integrals of a
single G-function can always be computed, and the definite integral
of a product of two G-functions can be computed from zero to
infinity. Various strategies are implemented to rewrite integrands
as G-functions, and use this information to compute integrals (see
the ``meijerint`` module).
The option manual=True can be used to use only an algorithm that tries
to mimic integration by hand. This algorithm does not handle as many
integrands as the other algorithms implemented but may return results in
a more familiar form. The ``manualintegrate`` module has functions that
return the steps used (see the module docstring for more information).
In general, the algebraic methods work best for computing
antiderivatives of (possibly complicated) combinations of elementary
functions. The G-function methods work best for computing definite
integrals from zero to infinity of moderately complicated
combinations of special functions, or indefinite integrals of very
simple combinations of special functions.
The strategy employed by the integration code is as follows:
- If computing a definite integral, and both limits are real,
and at least one limit is +- oo, try the G-function method of
definite integration first.
- Try to find an antiderivative, using all available methods, ordered
by performance (that is try fastest method first, slowest last; in
particular polynomial integration is tried first, Meijer
G-functions second to last, and heuristic Risch last).
- If still not successful, try G-functions irrespective of the
limits.
The option meijerg=True, False, None can be used to, respectively:
always use G-function methods and no others, never use G-function
methods, or use all available methods (in order as described above).
It defaults to None.
Examples
========
>>> from sympy import integrate, log, exp, oo
>>> from sympy.abc import a, x, y
>>> integrate(x*y, x)
x**2*y/2
>>> integrate(log(x), x)
x*log(x) - x
>>> integrate(log(x), (x, 1, a))
a*log(a) - a + 1
>>> integrate(x)
x**2/2
Terms that are independent of x are dropped by indefinite integration:
>>> from sympy import sqrt
>>> integrate(sqrt(1 + x), (x, 0, x))
2*(x + 1)**(3/2)/3 - 2/3
>>> integrate(sqrt(1 + x), x)
2*(x + 1)**(3/2)/3
>>> integrate(x*y)
Traceback (most recent call last):
...
ValueError: specify integration variables to integrate x*y
Note that ``integrate(x)`` syntax is meant only for convenience
in interactive sessions and should be avoided in library code.
>>> integrate(x**a*exp(-x), (x, 0, oo)) # same as conds='piecewise'
Piecewise((gamma(a + 1), -re(a) < 1),
(Integral(x**a*exp(-x), (x, 0, oo)), True))
>>> integrate(x**a*exp(-x), (x, 0, oo), conds='none')
gamma(a + 1)
>>> integrate(x**a*exp(-x), (x, 0, oo), conds='separate')
(gamma(a + 1), -re(a) < 1)
See Also
========
Integral, Integral.doit
"""
doit_flags = {
'deep': False,
'meijerg': kwargs.pop('meijerg', None),
'conds': kwargs.pop('conds', 'piecewise'),
'risch': kwargs.pop('risch', None),
'heurisch': kwargs.pop('heurisch', None),
'manual': kwargs.pop('manual', None)
}
integral = Integral(*args, **kwargs)
if isinstance(integral, Integral):
return integral.doit(**doit_flags)
else:
new_args = [a.doit(**doit_flags) if isinstance(a, Integral) else a
for a in integral.args]
return integral.func(*new_args)
def line_integrate(field, curve, vars):
"""line_integrate(field, Curve, variables)
Compute the line integral.
Examples
========
>>> from sympy import Curve, line_integrate, E, ln
>>> from sympy.abc import x, y, t
>>> C = Curve([E**t + 1, E**t - 1], (t, 0, ln(2)))
>>> line_integrate(x + y, C, [x, y])
3*sqrt(2)
See Also
========
integrate, Integral
"""
from sympy.geometry import Curve
F = sympify(field)
if not F:
raise ValueError(
"Expecting function specifying field as first argument.")
if not isinstance(curve, Curve):
raise ValueError("Expecting Curve entity as second argument.")
if not is_sequence(vars):
raise ValueError("Expecting ordered iterable for variables.")
if len(curve.functions) != len(vars):
raise ValueError("Field variable size does not match curve dimension.")
if curve.parameter in vars:
raise ValueError("Curve parameter clashes with field parameters.")
# Calculate derivatives for line parameter functions
# F(r) -> F(r(t)) and finally F(r(t)*r'(t))
Ft = F
dldt = 0
for i, var in enumerate(vars):
_f = curve.functions[i]
_dn = diff(_f, curve.parameter)
# ...arc length
dldt = dldt + (_dn * _dn)
Ft = Ft.subs(var, _f)
Ft = Ft * sqrt(dldt)
integral = Integral(Ft, curve.limits).doit(deep=False)
return integral
|
91f93721a9aa191392432ff048359dc9a8adf9f230b919e0d695c69970792021
|
"""Base class for all the objects in SymPy"""
from __future__ import print_function, division
from collections import defaultdict
from itertools import chain
from .assumptions import BasicMeta, ManagedProperties
from .cache import cacheit
from .sympify import _sympify, sympify, SympifyError
from .compatibility import (iterable, Iterator, ordered,
string_types, with_metaclass, zip_longest, range, PY3, Mapping)
from .singleton import S
from inspect import getmro
def as_Basic(expr):
"""Return expr as a Basic instance using strict sympify
or raise a TypeError; this is just a wrapper to _sympify,
raising a TypeError instead of a SympifyError."""
from sympy.utilities.misc import func_name
try:
return _sympify(expr)
except SympifyError:
raise TypeError(
'Argument must be a Basic object, not `%s`' % func_name(
expr))
class Basic(with_metaclass(ManagedProperties)):
"""
Base class for all objects in SymPy.
Conventions:
1) Always use ``.args``, when accessing parameters of some instance:
>>> from sympy import cot
>>> from sympy.abc import x, y
>>> cot(x).args
(x,)
>>> cot(x).args[0]
x
>>> (x*y).args
(x, y)
>>> (x*y).args[1]
y
2) Never use internal methods or variables (the ones prefixed with ``_``):
>>> cot(x)._args # do not use this, use cot(x).args instead
(x,)
"""
__slots__ = ['_mhash', # hash value
'_args', # arguments
'_assumptions'
]
# To be overridden with True in the appropriate subclasses
is_number = False
is_Atom = False
is_Symbol = False
is_symbol = False
is_Indexed = False
is_Dummy = False
is_Wild = False
is_Function = False
is_Add = False
is_Mul = False
is_Pow = False
is_Number = False
is_Float = False
is_Rational = False
is_Integer = False
is_NumberSymbol = False
is_Order = False
is_Derivative = False
is_Piecewise = False
is_Poly = False
is_AlgebraicNumber = False
is_Relational = False
is_Equality = False
is_Boolean = False
is_Not = False
is_Matrix = False
is_Vector = False
is_Point = False
is_MatAdd = False
is_MatMul = False
def __new__(cls, *args):
obj = object.__new__(cls)
obj._assumptions = cls.default_assumptions
obj._mhash = None # will be set by __hash__ method.
obj._args = args # all items in args must be Basic objects
return obj
def copy(self):
return self.func(*self.args)
def __reduce_ex__(self, proto):
""" Pickling support."""
return type(self), self.__getnewargs__(), self.__getstate__()
def __getnewargs__(self):
return self.args
def __getstate__(self):
return {}
def __setstate__(self, state):
for k, v in state.items():
setattr(self, k, v)
def __hash__(self):
# hash cannot be cached using cache_it because infinite recurrence
# occurs as hash is needed for setting cache dictionary keys
h = self._mhash
if h is None:
h = hash((type(self).__name__,) + self._hashable_content())
self._mhash = h
return h
def _hashable_content(self):
"""Return a tuple of information about self that can be used to
compute the hash. If a class defines additional attributes,
like ``name`` in Symbol, then this method should be updated
accordingly to return such relevant attributes.
Defining more than _hashable_content is necessary if __eq__ has
been defined by a class. See note about this in Basic.__eq__."""
return self._args
@property
def assumptions0(self):
"""
Return object `type` assumptions.
For example:
Symbol('x', real=True)
Symbol('x', integer=True)
are different objects. In other words, besides Python type (Symbol in
this case), the initial assumptions are also forming their typeinfo.
Examples
========
>>> from sympy import Symbol
>>> from sympy.abc import x
>>> x.assumptions0
{'commutative': True}
>>> x = Symbol("x", positive=True)
>>> x.assumptions0
{'commutative': True, 'complex': True, 'hermitian': True,
'imaginary': False, 'negative': False, 'nonnegative': True,
'nonpositive': False, 'nonzero': True, 'positive': True, 'real': True,
'zero': False}
"""
return {}
def compare(self, other):
"""
Return -1, 0, 1 if the object is smaller, equal, or greater than other.
Not in the mathematical sense. If the object is of a different type
from the "other" then their classes are ordered according to
the sorted_classes list.
Examples
========
>>> from sympy.abc import x, y
>>> x.compare(y)
-1
>>> x.compare(x)
0
>>> y.compare(x)
1
"""
# all redefinitions of __cmp__ method should start with the
# following lines:
if self is other:
return 0
n1 = self.__class__
n2 = other.__class__
c = (n1 > n2) - (n1 < n2)
if c:
return c
#
st = self._hashable_content()
ot = other._hashable_content()
c = (len(st) > len(ot)) - (len(st) < len(ot))
if c:
return c
for l, r in zip(st, ot):
l = Basic(*l) if isinstance(l, frozenset) else l
r = Basic(*r) if isinstance(r, frozenset) else r
if isinstance(l, Basic):
c = l.compare(r)
else:
c = (l > r) - (l < r)
if c:
return c
return 0
@staticmethod
def _compare_pretty(a, b):
from sympy.series.order import Order
if isinstance(a, Order) and not isinstance(b, Order):
return 1
if not isinstance(a, Order) and isinstance(b, Order):
return -1
if a.is_Rational and b.is_Rational:
l = a.p * b.q
r = b.p * a.q
return (l > r) - (l < r)
else:
from sympy.core.symbol import Wild
p1, p2, p3 = Wild("p1"), Wild("p2"), Wild("p3")
r_a = a.match(p1 * p2**p3)
if r_a and p3 in r_a:
a3 = r_a[p3]
r_b = b.match(p1 * p2**p3)
if r_b and p3 in r_b:
b3 = r_b[p3]
c = Basic.compare(a3, b3)
if c != 0:
return c
return Basic.compare(a, b)
@classmethod
def fromiter(cls, args, **assumptions):
"""
Create a new object from an iterable.
This is a convenience function that allows one to create objects from
any iterable, without having to convert to a list or tuple first.
Examples
========
>>> from sympy import Tuple
>>> Tuple.fromiter(i for i in range(5))
(0, 1, 2, 3, 4)
"""
return cls(*tuple(args), **assumptions)
@classmethod
def class_key(cls):
"""Nice order of classes. """
return 5, 0, cls.__name__
@cacheit
def sort_key(self, order=None):
"""
Return a sort key.
Examples
========
>>> from sympy.core import S, I
>>> sorted([S(1)/2, I, -I], key=lambda x: x.sort_key())
[1/2, -I, I]
>>> S("[x, 1/x, 1/x**2, x**2, x**(1/2), x**(1/4), x**(3/2)]")
[x, 1/x, x**(-2), x**2, sqrt(x), x**(1/4), x**(3/2)]
>>> sorted(_, key=lambda x: x.sort_key())
[x**(-2), 1/x, x**(1/4), sqrt(x), x, x**(3/2), x**2]
"""
# XXX: remove this when issue 5169 is fixed
def inner_key(arg):
if isinstance(arg, Basic):
return arg.sort_key(order)
else:
return arg
args = self._sorted_args
args = len(args), tuple([inner_key(arg) for arg in args])
return self.class_key(), args, S.One.sort_key(), S.One
def __eq__(self, other):
"""Return a boolean indicating whether a == b on the basis of
their symbolic trees.
This is the same as a.compare(b) == 0 but faster.
Notes
=====
If a class that overrides __eq__() needs to retain the
implementation of __hash__() from a parent class, the
interpreter must be told this explicitly by setting __hash__ =
<ParentClass>.__hash__. Otherwise the inheritance of __hash__()
will be blocked, just as if __hash__ had been explicitly set to
None.
References
==========
from http://docs.python.org/dev/reference/datamodel.html#object.__hash__
"""
if self is other:
return True
tself = type(self)
tother = type(other)
if type(self) is not type(other):
try:
other = _sympify(other)
tother = type(other)
except SympifyError:
return NotImplemented
# As long as we have the ordering of classes (sympy.core),
# comparing types will be slow in Python 2, because it uses
# __cmp__. Until we can remove it
# (https://github.com/sympy/sympy/issues/4269), we only compare
# types in Python 2 directly if they actually have __ne__.
if PY3 or type(tself).__ne__ is not type.__ne__:
if tself != tother:
return False
elif tself is not tother:
return False
return self._hashable_content() == other._hashable_content()
def __ne__(self, other):
"""a != b -> Compare two symbolic trees and see whether they are different
this is the same as:
a.compare(b) != 0
but faster
"""
return not self == other
def dummy_eq(self, other, symbol=None):
"""
Compare two expressions and handle dummy symbols.
Examples
========
>>> from sympy import Dummy
>>> from sympy.abc import x, y
>>> u = Dummy('u')
>>> (u**2 + 1).dummy_eq(x**2 + 1)
True
>>> (u**2 + 1) == (x**2 + 1)
False
>>> (u**2 + y).dummy_eq(x**2 + y, x)
True
>>> (u**2 + y).dummy_eq(x**2 + y, y)
False
"""
s = self.as_dummy()
o = _sympify(other)
o = o.as_dummy()
dummy_symbols = [i for i in s.free_symbols if i.is_Dummy]
if len(dummy_symbols) == 1:
dummy = dummy_symbols.pop()
else:
return s == o
if symbol is None:
symbols = o.free_symbols
if len(symbols) == 1:
symbol = symbols.pop()
else:
return s == o
tmp = dummy.__class__()
return s.subs(dummy, tmp) == o.subs(symbol, tmp)
# Note, we always use the default ordering (lex) in __str__ and __repr__,
# regardless of the global setting. See issue 5487.
def __repr__(self):
"""Method to return the string representation.
Return the expression as a string.
"""
from sympy.printing import sstr
return sstr(self, order=None)
def __str__(self):
from sympy.printing import sstr
return sstr(self, order=None)
# We don't define _repr_png_ here because it would add a large amount of
# data to any notebook containing SymPy expressions, without adding
# anything useful to the notebook. It can still enabled manually, e.g.,
# for the qtconsole, with init_printing().
def _repr_latex_(self):
"""
IPython/Jupyter LaTeX printing
To change the behavior of this (e.g., pass in some settings to LaTeX),
use init_printing(). init_printing() will also enable LaTeX printing
for built in numeric types like ints and container types that contain
SymPy objects, like lists and dictionaries of expressions.
"""
from sympy.printing.latex import latex
s = latex(self, mode='plain')
return "$\\displaystyle %s$" % s
_repr_latex_orig = _repr_latex_
def atoms(self, *types):
"""Returns the atoms that form the current object.
By default, only objects that are truly atomic and can't
be divided into smaller pieces are returned: symbols, numbers,
and number symbols like I and pi. It is possible to request
atoms of any type, however, as demonstrated below.
Examples
========
>>> from sympy import I, pi, sin
>>> from sympy.abc import x, y
>>> (1 + x + 2*sin(y + I*pi)).atoms()
{1, 2, I, pi, x, y}
If one or more types are given, the results will contain only
those types of atoms.
>>> from sympy import Number, NumberSymbol, Symbol
>>> (1 + x + 2*sin(y + I*pi)).atoms(Symbol)
{x, y}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number)
{1, 2}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number, NumberSymbol)
{1, 2, pi}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Number, NumberSymbol, I)
{1, 2, I, pi}
Note that I (imaginary unit) and zoo (complex infinity) are special
types of number symbols and are not part of the NumberSymbol class.
The type can be given implicitly, too:
>>> (1 + x + 2*sin(y + I*pi)).atoms(x) # x is a Symbol
{x, y}
Be careful to check your assumptions when using the implicit option
since ``S(1).is_Integer = True`` but ``type(S(1))`` is ``One``, a special type
of sympy atom, while ``type(S(2))`` is type ``Integer`` and will find all
integers in an expression:
>>> from sympy import S
>>> (1 + x + 2*sin(y + I*pi)).atoms(S(1))
{1}
>>> (1 + x + 2*sin(y + I*pi)).atoms(S(2))
{1, 2}
Finally, arguments to atoms() can select more than atomic atoms: any
sympy type (loaded in core/__init__.py) can be listed as an argument
and those types of "atoms" as found in scanning the arguments of the
expression recursively:
>>> from sympy import Function, Mul
>>> from sympy.core.function import AppliedUndef
>>> f = Function('f')
>>> (1 + f(x) + 2*sin(y + I*pi)).atoms(Function)
{f(x), sin(y + I*pi)}
>>> (1 + f(x) + 2*sin(y + I*pi)).atoms(AppliedUndef)
{f(x)}
>>> (1 + x + 2*sin(y + I*pi)).atoms(Mul)
{I*pi, 2*sin(y + I*pi)}
"""
if types:
types = tuple(
[t if isinstance(t, type) else type(t) for t in types])
else:
types = (Atom,)
result = set()
for expr in preorder_traversal(self):
if isinstance(expr, types):
result.add(expr)
return result
@property
def free_symbols(self):
"""Return from the atoms of self those which are free symbols.
For most expressions, all symbols are free symbols. For some classes
this is not true. e.g. Integrals use Symbols for the dummy variables
which are bound variables, so Integral has a method to return all
symbols except those. Derivative keeps track of symbols with respect
to which it will perform a derivative; those are
bound variables, too, so it has its own free_symbols method.
Any other method that uses bound variables should implement a
free_symbols method."""
return set().union(*[a.free_symbols for a in self.args])
@property
def expr_free_symbols(self):
return set([])
def as_dummy(self):
"""Return the expression with any objects having structurally
bound symbols replaced with unique, canonical symbols within
the object in which they appear and having only the default
assumption for commutativity being True.
Examples
========
>>> from sympy import Integral, Symbol
>>> from sympy.abc import x, y
>>> r = Symbol('r', real=True)
>>> Integral(r, (r, x)).as_dummy()
Integral(_0, (_0, x))
>>> _.variables[0].is_real is None
True
Notes
=====
Any object that has structural dummy variables should have
a property, `bound_symbols` that returns a list of structural
dummy symbols of the object itself.
Lambda and Subs have bound symbols, but because of how they
are cached, they already compare the same regardless of their
bound symbols:
>>> from sympy import Lambda
>>> Lambda(x, x + 1) == Lambda(y, y + 1)
True
"""
def can(x):
d = dict([(i, i.as_dummy()) for i in x.bound_symbols])
# mask free that shadow bound
x = x.subs(d)
c = x.canonical_variables
# replace bound
x = x.xreplace(c)
# undo masking
x = x.xreplace(dict((v, k) for k, v in d.items()))
return x
return self.replace(
lambda x: hasattr(x, 'bound_symbols'),
lambda x: can(x))
@property
def canonical_variables(self):
"""Return a dictionary mapping any variable defined in
``self.bound_symbols`` to Symbols that do not clash
with any existing symbol in the expression.
Examples
========
>>> from sympy import Lambda
>>> from sympy.abc import x
>>> Lambda(x, 2*x).canonical_variables
{x: _0}
"""
from sympy.core.symbol import Symbol
from sympy.utilities.iterables import numbered_symbols
if not hasattr(self, 'bound_symbols'):
return {}
dums = numbered_symbols('_')
reps = {}
v = self.bound_symbols
# this free will include bound symbols that are not part of
# self's bound symbols
free = set([i.name for i in self.atoms(Symbol) - set(v)])
for v in v:
d = next(dums)
if v.is_Symbol:
while v.name == d.name or d.name in free:
d = next(dums)
reps[v] = d
return reps
def rcall(self, *args):
"""Apply on the argument recursively through the expression tree.
This method is used to simulate a common abuse of notation for
operators. For instance in SymPy the the following will not work:
``(x+Lambda(y, 2*y))(z) == x+2*z``,
however you can use
>>> from sympy import Lambda
>>> from sympy.abc import x, y, z
>>> (x + Lambda(y, 2*y)).rcall(z)
x + 2*z
"""
return Basic._recursive_call(self, args)
@staticmethod
def _recursive_call(expr_to_call, on_args):
"""Helper for rcall method.
"""
from sympy import Symbol
def the_call_method_is_overridden(expr):
for cls in getmro(type(expr)):
if '__call__' in cls.__dict__:
return cls != Basic
if callable(expr_to_call) and the_call_method_is_overridden(expr_to_call):
if isinstance(expr_to_call, Symbol): # XXX When you call a Symbol it is
return expr_to_call # transformed into an UndefFunction
else:
return expr_to_call(*on_args)
elif expr_to_call.args:
args = [Basic._recursive_call(
sub, on_args) for sub in expr_to_call.args]
return type(expr_to_call)(*args)
else:
return expr_to_call
def is_hypergeometric(self, k):
from sympy.simplify import hypersimp
return hypersimp(self, k) is not None
@property
def is_comparable(self):
"""Return True if self can be computed to a real number
(or already is a real number) with precision, else False.
Examples
========
>>> from sympy import exp_polar, pi, I
>>> (I*exp_polar(I*pi/2)).is_comparable
True
>>> (I*exp_polar(I*pi*2)).is_comparable
False
A False result does not mean that `self` cannot be rewritten
into a form that would be comparable. For example, the
difference computed below is zero but without simplification
it does not evaluate to a zero with precision:
>>> e = 2**pi*(1 + 2**pi)
>>> dif = e - e.expand()
>>> dif.is_comparable
False
>>> dif.n(2)._prec
1
"""
is_real = self.is_real
if is_real is False:
return False
if not self.is_number:
return False
# don't re-eval numbers that are already evaluated since
# this will create spurious precision
n, i = [p.evalf(2) if not p.is_Number else p
for p in self.as_real_imag()]
if not (i.is_Number and n.is_Number):
return False
if i:
# if _prec = 1 we can't decide and if not,
# the answer is False because numbers with
# imaginary parts can't be compared
# so return False
return False
else:
return n._prec != 1
@property
def func(self):
"""
The top-level function in an expression.
The following should hold for all objects::
>> x == x.func(*x.args)
Examples
========
>>> from sympy.abc import x
>>> a = 2*x
>>> a.func
<class 'sympy.core.mul.Mul'>
>>> a.args
(2, x)
>>> a.func(*a.args)
2*x
>>> a == a.func(*a.args)
True
"""
return self.__class__
@property
def args(self):
"""Returns a tuple of arguments of 'self'.
Examples
========
>>> from sympy import cot
>>> from sympy.abc import x, y
>>> cot(x).args
(x,)
>>> cot(x).args[0]
x
>>> (x*y).args
(x, y)
>>> (x*y).args[1]
y
Notes
=====
Never use self._args, always use self.args.
Only use _args in __new__ when creating a new function.
Don't override .args() from Basic (so that it's easy to
change the interface in the future if needed).
"""
return self._args
@property
def _sorted_args(self):
"""
The same as ``args``. Derived classes which don't fix an
order on their arguments should override this method to
produce the sorted representation.
"""
return self.args
def as_poly(self, *gens, **args):
"""Converts ``self`` to a polynomial or returns ``None``.
>>> from sympy import sin
>>> from sympy.abc import x, y
>>> print((x**2 + x*y).as_poly())
Poly(x**2 + x*y, x, y, domain='ZZ')
>>> print((x**2 + x*y).as_poly(x, y))
Poly(x**2 + x*y, x, y, domain='ZZ')
>>> print((x**2 + sin(y)).as_poly(x, y))
None
"""
from sympy.polys import Poly, PolynomialError
try:
poly = Poly(self, *gens, **args)
if not poly.is_Poly:
return None
else:
return poly
except PolynomialError:
return None
def as_content_primitive(self, radical=False, clear=True):
"""A stub to allow Basic args (like Tuple) to be skipped when computing
the content and primitive components of an expression.
See Also
========
sympy.core.expr.Expr.as_content_primitive
"""
return S.One, self
def subs(self, *args, **kwargs):
"""
Substitutes old for new in an expression after sympifying args.
`args` is either:
- two arguments, e.g. foo.subs(old, new)
- one iterable argument, e.g. foo.subs(iterable). The iterable may be
o an iterable container with (old, new) pairs. In this case the
replacements are processed in the order given with successive
patterns possibly affecting replacements already made.
o a dict or set whose key/value items correspond to old/new pairs.
In this case the old/new pairs will be sorted by op count and in
case of a tie, by number of args and the default_sort_key. The
resulting sorted list is then processed as an iterable container
(see previous).
If the keyword ``simultaneous`` is True, the subexpressions will not be
evaluated until all the substitutions have been made.
Examples
========
>>> from sympy import pi, exp, limit, oo
>>> from sympy.abc import x, y
>>> (1 + x*y).subs(x, pi)
pi*y + 1
>>> (1 + x*y).subs({x:pi, y:2})
1 + 2*pi
>>> (1 + x*y).subs([(x, pi), (y, 2)])
1 + 2*pi
>>> reps = [(y, x**2), (x, 2)]
>>> (x + y).subs(reps)
6
>>> (x + y).subs(reversed(reps))
x**2 + 2
>>> (x**2 + x**4).subs(x**2, y)
y**2 + y
To replace only the x**2 but not the x**4, use xreplace:
>>> (x**2 + x**4).xreplace({x**2: y})
x**4 + y
To delay evaluation until all substitutions have been made,
set the keyword ``simultaneous`` to True:
>>> (x/y).subs([(x, 0), (y, 0)])
0
>>> (x/y).subs([(x, 0), (y, 0)], simultaneous=True)
nan
This has the added feature of not allowing subsequent substitutions
to affect those already made:
>>> ((x + y)/y).subs({x + y: y, y: x + y})
1
>>> ((x + y)/y).subs({x + y: y, y: x + y}, simultaneous=True)
y/(x + y)
In order to obtain a canonical result, unordered iterables are
sorted by count_op length, number of arguments and by the
default_sort_key to break any ties. All other iterables are left
unsorted.
>>> from sympy import sqrt, sin, cos
>>> from sympy.abc import a, b, c, d, e
>>> A = (sqrt(sin(2*x)), a)
>>> B = (sin(2*x), b)
>>> C = (cos(2*x), c)
>>> D = (x, d)
>>> E = (exp(x), e)
>>> expr = sqrt(sin(2*x))*sin(exp(x)*x)*cos(2*x) + sin(2*x)
>>> expr.subs(dict([A, B, C, D, E]))
a*c*sin(d*e) + b
The resulting expression represents a literal replacement of the
old arguments with the new arguments. This may not reflect the
limiting behavior of the expression:
>>> (x**3 - 3*x).subs({x: oo})
nan
>>> limit(x**3 - 3*x, x, oo)
oo
If the substitution will be followed by numerical
evaluation, it is better to pass the substitution to
evalf as
>>> (1/x).evalf(subs={x: 3.0}, n=21)
0.333333333333333333333
rather than
>>> (1/x).subs({x: 3.0}).evalf(21)
0.333333333333333314830
as the former will ensure that the desired level of precision is
obtained.
See Also
========
replace: replacement capable of doing wildcard-like matching,
parsing of match, and conditional replacements
xreplace: exact node replacement in expr tree; also capable of
using matching rules
evalf: calculates the given formula to a desired level of precision
"""
from sympy.core.containers import Dict
from sympy.utilities import default_sort_key
from sympy import Dummy, Symbol
unordered = False
if len(args) == 1:
sequence = args[0]
if isinstance(sequence, set):
unordered = True
elif isinstance(sequence, (Dict, Mapping)):
unordered = True
sequence = sequence.items()
elif not iterable(sequence):
from sympy.utilities.misc import filldedent
raise ValueError(filldedent("""
When a single argument is passed to subs
it should be a dictionary of old: new pairs or an iterable
of (old, new) tuples."""))
elif len(args) == 2:
sequence = [args]
else:
raise ValueError("subs accepts either 1 or 2 arguments")
sequence = list(sequence)
for i, s in enumerate(sequence):
if type(s[0]) is str:
# when old is a string we prefer Symbol
s = Symbol(s[0]), s[1]
try:
s = [sympify(_, strict=type(_) is not str) for _ in s]
except SympifyError:
# if it can't be sympified, skip it
sequence[i] = None
continue
# skip if there is no change
sequence[i] = None if _aresame(*s) else tuple(s)
sequence = list(filter(None, sequence))
if unordered:
sequence = dict(sequence)
if not all(k.is_Atom for k in sequence):
d = {}
for o, n in sequence.items():
try:
ops = o.count_ops(), len(o.args)
except TypeError:
ops = (0, 0)
d.setdefault(ops, []).append((o, n))
newseq = []
for k in sorted(d.keys(), reverse=True):
newseq.extend(
sorted([v[0] for v in d[k]], key=default_sort_key))
sequence = [(k, sequence[k]) for k in newseq]
del newseq, d
else:
sequence = sorted([(k, v) for (k, v) in sequence.items()],
key=default_sort_key)
if kwargs.pop('simultaneous', False): # XXX should this be the default for dict subs?
reps = {}
rv = self
kwargs['hack2'] = True
m = Dummy()
for old, new in sequence:
d = Dummy(commutative=new.is_commutative)
# using d*m so Subs will be used on dummy variables
# in things like Derivative(f(x, y), x) in which x
# is both free and bound
rv = rv._subs(old, d*m, **kwargs)
if not isinstance(rv, Basic):
break
reps[d] = new
reps[m] = S.One # get rid of m
return rv.xreplace(reps)
else:
rv = self
for old, new in sequence:
rv = rv._subs(old, new, **kwargs)
if not isinstance(rv, Basic):
break
return rv
@cacheit
def _subs(self, old, new, **hints):
"""Substitutes an expression old -> new.
If self is not equal to old then _eval_subs is called.
If _eval_subs doesn't want to make any special replacement
then a None is received which indicates that the fallback
should be applied wherein a search for replacements is made
amongst the arguments of self.
>>> from sympy import Add
>>> from sympy.abc import x, y, z
Examples
========
Add's _eval_subs knows how to target x + y in the following
so it makes the change:
>>> (x + y + z).subs(x + y, 1)
z + 1
Add's _eval_subs doesn't need to know how to find x + y in
the following:
>>> Add._eval_subs(z*(x + y) + 3, x + y, 1) is None
True
The returned None will cause the fallback routine to traverse the args and
pass the z*(x + y) arg to Mul where the change will take place and the
substitution will succeed:
>>> (z*(x + y) + 3).subs(x + y, 1)
z + 3
** Developers Notes **
An _eval_subs routine for a class should be written if:
1) any arguments are not instances of Basic (e.g. bool, tuple);
2) some arguments should not be targeted (as in integration
variables);
3) if there is something other than a literal replacement
that should be attempted (as in Piecewise where the condition
may be updated without doing a replacement).
If it is overridden, here are some special cases that might arise:
1) If it turns out that no special change was made and all
the original sub-arguments should be checked for
replacements then None should be returned.
2) If it is necessary to do substitutions on a portion of
the expression then _subs should be called. _subs will
handle the case of any sub-expression being equal to old
(which usually would not be the case) while its fallback
will handle the recursion into the sub-arguments. For
example, after Add's _eval_subs removes some matching terms
it must process the remaining terms so it calls _subs
on each of the un-matched terms and then adds them
onto the terms previously obtained.
3) If the initial expression should remain unchanged then
the original expression should be returned. (Whenever an
expression is returned, modified or not, no further
substitution of old -> new is attempted.) Sum's _eval_subs
routine uses this strategy when a substitution is attempted
on any of its summation variables.
"""
def fallback(self, old, new):
"""
Try to replace old with new in any of self's arguments.
"""
hit = False
args = list(self.args)
for i, arg in enumerate(args):
if not hasattr(arg, '_eval_subs'):
continue
arg = arg._subs(old, new, **hints)
if not _aresame(arg, args[i]):
hit = True
args[i] = arg
if hit:
rv = self.func(*args)
hack2 = hints.get('hack2', False)
if hack2 and self.is_Mul and not rv.is_Mul: # 2-arg hack
coeff = S.One
nonnumber = []
for i in args:
if i.is_Number:
coeff *= i
else:
nonnumber.append(i)
nonnumber = self.func(*nonnumber)
if coeff is S.One:
return nonnumber
else:
return self.func(coeff, nonnumber, evaluate=False)
return rv
return self
if _aresame(self, old):
return new
rv = self._eval_subs(old, new)
if rv is None:
rv = fallback(self, old, new)
return rv
def _eval_subs(self, old, new):
"""Override this stub if you want to do anything more than
attempt a replacement of old with new in the arguments of self.
See also: _subs
"""
return None
def xreplace(self, rule):
"""
Replace occurrences of objects within the expression.
Parameters
==========
rule : dict-like
Expresses a replacement rule
Returns
=======
xreplace : the result of the replacement
Examples
========
>>> from sympy import symbols, pi, exp
>>> x, y, z = symbols('x y z')
>>> (1 + x*y).xreplace({x: pi})
pi*y + 1
>>> (1 + x*y).xreplace({x: pi, y: 2})
1 + 2*pi
Replacements occur only if an entire node in the expression tree is
matched:
>>> (x*y + z).xreplace({x*y: pi})
z + pi
>>> (x*y*z).xreplace({x*y: pi})
x*y*z
>>> (2*x).xreplace({2*x: y, x: z})
y
>>> (2*2*x).xreplace({2*x: y, x: z})
4*z
>>> (x + y + 2).xreplace({x + y: 2})
x + y + 2
>>> (x + 2 + exp(x + 2)).xreplace({x + 2: y})
x + exp(y) + 2
xreplace doesn't differentiate between free and bound symbols. In the
following, subs(x, y) would not change x since it is a bound symbol,
but xreplace does:
>>> from sympy import Integral
>>> Integral(x, (x, 1, 2*x)).xreplace({x: y})
Integral(y, (y, 1, 2*y))
Trying to replace x with an expression raises an error:
>>> Integral(x, (x, 1, 2*x)).xreplace({x: 2*y}) # doctest: +SKIP
ValueError: Invalid limits given: ((2*y, 1, 4*y),)
See Also
========
replace: replacement capable of doing wildcard-like matching,
parsing of match, and conditional replacements
subs: substitution of subexpressions as defined by the objects
themselves.
"""
value, _ = self._xreplace(rule)
return value
def _xreplace(self, rule):
"""
Helper for xreplace. Tracks whether a replacement actually occurred.
"""
if self in rule:
return rule[self], True
elif rule:
args = []
changed = False
for a in self.args:
try:
a_xr = a._xreplace(rule)
args.append(a_xr[0])
changed |= a_xr[1]
except AttributeError:
args.append(a)
args = tuple(args)
if changed:
return self.func(*args), True
return self, False
@cacheit
def has(self, *patterns):
"""
Test whether any subexpression matches any of the patterns.
Examples
========
>>> from sympy import sin
>>> from sympy.abc import x, y, z
>>> (x**2 + sin(x*y)).has(z)
False
>>> (x**2 + sin(x*y)).has(x, y, z)
True
>>> x.has(x)
True
Note ``has`` is a structural algorithm with no knowledge of
mathematics. Consider the following half-open interval:
>>> from sympy.sets import Interval
>>> i = Interval.Lopen(0, 5); i
Interval.Lopen(0, 5)
>>> i.args
(0, 5, True, False)
>>> i.has(4) # there is no "4" in the arguments
False
>>> i.has(0) # there *is* a "0" in the arguments
True
Instead, use ``contains`` to determine whether a number is in the
interval or not:
>>> i.contains(4)
True
>>> i.contains(0)
False
Note that ``expr.has(*patterns)`` is exactly equivalent to
``any(expr.has(p) for p in patterns)``. In particular, ``False`` is
returned when the list of patterns is empty.
>>> x.has()
False
"""
return any(self._has(pattern) for pattern in patterns)
def _has(self, pattern):
"""Helper for .has()"""
from sympy.core.function import UndefinedFunction, Function
if isinstance(pattern, UndefinedFunction):
return any(f.func == pattern or f == pattern
for f in self.atoms(Function, UndefinedFunction))
pattern = sympify(pattern)
if isinstance(pattern, BasicMeta):
return any(isinstance(arg, pattern)
for arg in preorder_traversal(self))
try:
match = pattern._has_matcher()
return any(match(arg) for arg in preorder_traversal(self))
except AttributeError:
return any(arg == pattern for arg in preorder_traversal(self))
def _has_matcher(self):
"""Helper for .has()"""
return lambda other: self == other
def replace(self, query, value, map=False, simultaneous=True, exact=False):
"""
Replace matching subexpressions of ``self`` with ``value``.
If ``map = True`` then also return the mapping {old: new} where ``old``
was a sub-expression found with query and ``new`` is the replacement
value for it. If the expression itself doesn't match the query, then
the returned value will be ``self.xreplace(map)`` otherwise it should
be ``self.subs(ordered(map.items()))``.
Traverses an expression tree and performs replacement of matching
subexpressions from the bottom to the top of the tree. The default
approach is to do the replacement in a simultaneous fashion so
changes made are targeted only once. If this is not desired or causes
problems, ``simultaneous`` can be set to False. In addition, if an
expression containing more than one Wild symbol is being used to match
subexpressions and the ``exact`` flag is True, then the match will only
succeed if non-zero values are received for each Wild that appears in
the match pattern.
The list of possible combinations of queries and replacement values
is listed below:
Examples
========
Initial setup
>>> from sympy import log, sin, cos, tan, Wild, Mul, Add
>>> from sympy.abc import x, y
>>> f = log(sin(x)) + tan(sin(x**2))
1.1. type -> type
obj.replace(type, newtype)
When object of type ``type`` is found, replace it with the
result of passing its argument(s) to ``newtype``.
>>> f.replace(sin, cos)
log(cos(x)) + tan(cos(x**2))
>>> sin(x).replace(sin, cos, map=True)
(cos(x), {sin(x): cos(x)})
>>> (x*y).replace(Mul, Add)
x + y
1.2. type -> func
obj.replace(type, func)
When object of type ``type`` is found, apply ``func`` to its
argument(s). ``func`` must be written to handle the number
of arguments of ``type``.
>>> f.replace(sin, lambda arg: sin(2*arg))
log(sin(2*x)) + tan(sin(2*x**2))
>>> (x*y).replace(Mul, lambda *args: sin(2*Mul(*args)))
sin(2*x*y)
2.1. pattern -> expr
obj.replace(pattern(wild), expr(wild))
Replace subexpressions matching ``pattern`` with the expression
written in terms of the Wild symbols in ``pattern``.
>>> a = Wild('a')
>>> f.replace(sin(a), tan(a))
log(tan(x)) + tan(tan(x**2))
>>> f.replace(sin(a), tan(a/2))
log(tan(x/2)) + tan(tan(x**2/2))
>>> f.replace(sin(a), a)
log(x) + tan(x**2)
>>> (x*y).replace(a*x, a)
y
When the default value of False is used with patterns that have
more than one Wild symbol, non-intuitive results may be obtained:
>>> b = Wild('b')
>>> (2*x).replace(a*x + b, b - a)
2/x
For this reason, the ``exact`` option can be used to make the
replacement only when the match gives non-zero values for all
Wild symbols:
>>> (2*x + y).replace(a*x + b, b - a, exact=True)
y - 2
>>> (2*x).replace(a*x + b, b - a, exact=True)
2*x
2.2. pattern -> func
obj.replace(pattern(wild), lambda wild: expr(wild))
All behavior is the same as in 2.1 but now a function in terms of
pattern variables is used rather than an expression:
>>> f.replace(sin(a), lambda a: sin(2*a))
log(sin(2*x)) + tan(sin(2*x**2))
3.1. func -> func
obj.replace(filter, func)
Replace subexpression ``e`` with ``func(e)`` if ``filter(e)``
is True.
>>> g = 2*sin(x**3)
>>> g.replace(lambda expr: expr.is_Number, lambda expr: expr**2)
4*sin(x**9)
The expression itself is also targeted by the query but is done in
such a fashion that changes are not made twice.
>>> e = x*(x*y + 1)
>>> e.replace(lambda x: x.is_Mul, lambda x: 2*x)
2*x*(2*x*y + 1)
See Also
========
subs: substitution of subexpressions as defined by the objects
themselves.
xreplace: exact node replacement in expr tree; also capable of
using matching rules
"""
from sympy.core.symbol import Dummy
from sympy.simplify.simplify import bottom_up
try:
query = _sympify(query)
except SympifyError:
pass
try:
value = _sympify(value)
except SympifyError:
pass
if isinstance(query, type):
_query = lambda expr: isinstance(expr, query)
if isinstance(value, type):
_value = lambda expr, result: value(*expr.args)
elif callable(value):
_value = lambda expr, result: value(*expr.args)
else:
raise TypeError(
"given a type, replace() expects another "
"type or a callable")
elif isinstance(query, Basic):
_query = lambda expr: expr.match(query)
# XXX remove the exact flag and make multi-symbol
# patterns use exact=True semantics; to do this the query must
# be tested to find out how many Wild symbols are present.
# See https://groups.google.com/forum/
# ?fromgroups=#!topic/sympy/zPzo5FtRiqI
# for a method of inspecting a function to know how many
# parameters it has.
if isinstance(value, Basic):
if exact:
_value = lambda expr, result: (value.subs(result)
if all(val for val in result.values()) else expr)
else:
_value = lambda expr, result: value.subs(result)
elif callable(value):
# match dictionary keys get the trailing underscore stripped
# from them and are then passed as keywords to the callable;
# if ``exact`` is True, only accept match if there are no null
# values amongst those matched.
if exact:
_value = lambda expr, result: (value(**dict([(
str(key)[:-1], val) for key, val in result.items()]))
if all(val for val in result.values()) else expr)
else:
_value = lambda expr, result: value(**dict([(
str(key)[:-1], val) for key, val in result.items()]))
else:
raise TypeError(
"given an expression, replace() expects "
"another expression or a callable")
elif callable(query):
_query = query
if callable(value):
_value = lambda expr, result: value(expr)
else:
raise TypeError(
"given a callable, replace() expects "
"another callable")
else:
raise TypeError(
"first argument to replace() must be a "
"type, an expression or a callable")
mapping = {} # changes that took place
mask = [] # the dummies that were used as change placeholders
def rec_replace(expr):
result = _query(expr)
if result or result == {}:
new = _value(expr, result)
if new is not None and new != expr:
mapping[expr] = new
if simultaneous:
# don't let this expression be changed during rebuilding
com = getattr(new, 'is_commutative', True)
if com is None:
com = True
d = Dummy(commutative=com)
mask.append((d, new))
expr = d
else:
expr = new
return expr
rv = bottom_up(self, rec_replace, atoms=True)
# restore original expressions for Dummy symbols
if simultaneous:
mask = list(reversed(mask))
for o, n in mask:
r = {o: n}
rv = rv.xreplace(r)
if not map:
return rv
else:
if simultaneous:
# restore subexpressions in mapping
for o, n in mask:
r = {o: n}
mapping = {k.xreplace(r): v.xreplace(r)
for k, v in mapping.items()}
return rv, mapping
def find(self, query, group=False):
"""Find all subexpressions matching a query. """
query = _make_find_query(query)
results = list(filter(query, preorder_traversal(self)))
if not group:
return set(results)
else:
groups = {}
for result in results:
if result in groups:
groups[result] += 1
else:
groups[result] = 1
return groups
def count(self, query):
"""Count the number of matching subexpressions. """
query = _make_find_query(query)
return sum(bool(query(sub)) for sub in preorder_traversal(self))
def matches(self, expr, repl_dict={}, old=False):
"""
Helper method for match() that looks for a match between Wild symbols
in self and expressions in expr.
Examples
========
>>> from sympy import symbols, Wild, Basic
>>> a, b, c = symbols('a b c')
>>> x = Wild('x')
>>> Basic(a + x, x).matches(Basic(a + b, c)) is None
True
>>> Basic(a + x, x).matches(Basic(a + b + c, b + c))
{x_: b + c}
"""
expr = sympify(expr)
if not isinstance(expr, self.__class__):
return None
if self == expr:
return repl_dict
if len(self.args) != len(expr.args):
return None
d = repl_dict.copy()
for arg, other_arg in zip(self.args, expr.args):
if arg == other_arg:
continue
d = arg.xreplace(d).matches(other_arg, d, old=old)
if d is None:
return None
return d
def match(self, pattern, old=False):
"""
Pattern matching.
Wild symbols match all.
Return ``None`` when expression (self) does not match
with pattern. Otherwise return a dictionary such that::
pattern.xreplace(self.match(pattern)) == self
Examples
========
>>> from sympy import Wild
>>> from sympy.abc import x, y
>>> p = Wild("p")
>>> q = Wild("q")
>>> r = Wild("r")
>>> e = (x+y)**(x+y)
>>> e.match(p**p)
{p_: x + y}
>>> e.match(p**q)
{p_: x + y, q_: x + y}
>>> e = (2*x)**2
>>> e.match(p*q**r)
{p_: 4, q_: x, r_: 2}
>>> (p*q**r).xreplace(e.match(p*q**r))
4*x**2
The ``old`` flag will give the old-style pattern matching where
expressions and patterns are essentially solved to give the
match. Both of the following give None unless ``old=True``:
>>> (x - 2).match(p - x, old=True)
{p_: 2*x - 2}
>>> (2/x).match(p*x, old=True)
{p_: 2/x**2}
"""
pattern = sympify(pattern)
return pattern.matches(self, old=old)
def count_ops(self, visual=None):
"""wrapper for count_ops that returns the operation count."""
from sympy import count_ops
return count_ops(self, visual)
def doit(self, **hints):
"""Evaluate objects that are not evaluated by default like limits,
integrals, sums and products. All objects of this kind will be
evaluated recursively, unless some species were excluded via 'hints'
or unless the 'deep' hint was set to 'False'.
>>> from sympy import Integral
>>> from sympy.abc import x
>>> 2*Integral(x, x)
2*Integral(x, x)
>>> (2*Integral(x, x)).doit()
x**2
>>> (2*Integral(x, x)).doit(deep=False)
2*Integral(x, x)
"""
if hints.get('deep', True):
terms = [term.doit(**hints) if isinstance(term, Basic) else term
for term in self.args]
return self.func(*terms)
else:
return self
def _eval_rewrite(self, pattern, rule, **hints):
if self.is_Atom:
if hasattr(self, rule):
return getattr(self, rule)()
return self
if hints.get('deep', True):
args = [a._eval_rewrite(pattern, rule, **hints)
if isinstance(a, Basic) else a
for a in self.args]
else:
args = self.args
if pattern is None or isinstance(self, pattern):
if hasattr(self, rule):
rewritten = getattr(self, rule)(*args, **hints)
if rewritten is not None:
return rewritten
return self.func(*args) if hints.get('evaluate', True) else self
def _accept_eval_derivative(self, s):
# This method needs to be overridden by array-like objects
return s._visit_eval_derivative_scalar(self)
def _visit_eval_derivative_scalar(self, base):
# Base is a scalar
# Types are (base: scalar, self: scalar)
return base._eval_derivative(self)
def _visit_eval_derivative_array(self, base):
# Types are (base: array/matrix, self: scalar)
# Base is some kind of array/matrix,
# it should have `.applyfunc(lambda x: x.diff(self)` implemented:
return base._eval_derivative(self)
def _eval_derivative_n_times(self, s, n):
# This is the default evaluator for derivatives (as called by `diff`
# and `Derivative`), it will attempt a loop to derive the expression
# `n` times by calling the corresponding `_eval_derivative` method,
# while leaving the derivative unevaluated if `n` is symbolic. This
# method should be overridden if the object has a closed form for its
# symbolic n-th derivative.
from sympy import Integer
if isinstance(n, (int, Integer)):
obj = self
for i in range(n):
obj2 = obj._accept_eval_derivative(s)
if obj == obj2 or obj2 is None:
break
obj = obj2
return obj2
else:
return None
def rewrite(self, *args, **hints):
""" Rewrite functions in terms of other functions.
Rewrites expression containing applications of functions
of one kind in terms of functions of different kind. For
example you can rewrite trigonometric functions as complex
exponentials or combinatorial functions as gamma function.
As a pattern this function accepts a list of functions to
to rewrite (instances of DefinedFunction class). As rule
you can use string or a destination function instance (in
this case rewrite() will use the str() function).
There is also the possibility to pass hints on how to rewrite
the given expressions. For now there is only one such hint
defined called 'deep'. When 'deep' is set to False it will
forbid functions to rewrite their contents.
Examples
========
>>> from sympy import sin, exp
>>> from sympy.abc import x
Unspecified pattern:
>>> sin(x).rewrite(exp)
-I*(exp(I*x) - exp(-I*x))/2
Pattern as a single function:
>>> sin(x).rewrite(sin, exp)
-I*(exp(I*x) - exp(-I*x))/2
Pattern as a list of functions:
>>> sin(x).rewrite([sin, ], exp)
-I*(exp(I*x) - exp(-I*x))/2
"""
if not args:
return self
else:
pattern = args[:-1]
if isinstance(args[-1], string_types):
rule = '_eval_rewrite_as_' + args[-1]
else:
try:
rule = '_eval_rewrite_as_' + args[-1].__name__
except:
rule = '_eval_rewrite_as_' + args[-1].__class__.__name__
if not pattern:
return self._eval_rewrite(None, rule, **hints)
else:
if iterable(pattern[0]):
pattern = pattern[0]
pattern = [p for p in pattern if self.has(p)]
if pattern:
return self._eval_rewrite(tuple(pattern), rule, **hints)
else:
return self
_constructor_postprocessor_mapping = {}
@classmethod
def _exec_constructor_postprocessors(cls, obj):
# WARNING: This API is experimental.
# This is an experimental API that introduces constructor
# postprosessors for SymPy Core elements. If an argument of a SymPy
# expression has a `_constructor_postprocessor_mapping` attribute, it will
# be interpreted as a dictionary containing lists of postprocessing
# functions for matching expression node names.
clsname = obj.__class__.__name__
postprocessors = defaultdict(list)
for i in obj.args:
try:
if i in Basic._constructor_postprocessor_mapping:
for k, v in Basic._constructor_postprocessor_mapping[i].items():
postprocessors[k].extend([j for j in v if j not in postprocessors[k]])
else:
postprocessor_mappings = (
Basic._constructor_postprocessor_mapping[cls].items()
for cls in type(i).mro()
if cls in Basic._constructor_postprocessor_mapping
)
for k, v in chain.from_iterable(postprocessor_mappings):
postprocessors[k].extend([j for j in v if j not in postprocessors[k]])
except TypeError:
pass
for f in postprocessors.get(clsname, []):
obj = f(obj)
if len(postprocessors) > 0 and obj not in Basic._constructor_postprocessor_mapping:
Basic._constructor_postprocessor_mapping[obj] = postprocessors
return obj
class Atom(Basic):
"""
A parent class for atomic things. An atom is an expression with no subexpressions.
Examples
========
Symbol, Number, Rational, Integer, ...
But not: Add, Mul, Pow, ...
"""
is_Atom = True
__slots__ = []
def matches(self, expr, repl_dict={}, old=False):
if self == expr:
return repl_dict
def xreplace(self, rule, hack2=False):
return rule.get(self, self)
def doit(self, **hints):
return self
@classmethod
def class_key(cls):
return 2, 0, cls.__name__
@cacheit
def sort_key(self, order=None):
return self.class_key(), (1, (str(self),)), S.One.sort_key(), S.One
def _eval_simplify(self, ratio, measure, rational, inverse):
return self
@property
def _sorted_args(self):
# this is here as a safeguard against accidentally using _sorted_args
# on Atoms -- they cannot be rebuilt as atom.func(*atom._sorted_args)
# since there are no args. So the calling routine should be checking
# to see that this property is not called for Atoms.
raise AttributeError('Atoms have no args. It might be necessary'
' to make a check for Atoms in the calling code.')
def _aresame(a, b):
"""Return True if a and b are structurally the same, else False.
Examples
========
To SymPy, 2.0 == 2:
>>> from sympy import S
>>> 2.0 == S(2)
True
Since a simple 'same or not' result is sometimes useful, this routine was
written to provide that query:
>>> from sympy.core.basic import _aresame
>>> _aresame(S(2.0), S(2))
False
"""
from .function import AppliedUndef, UndefinedFunction as UndefFunc
for i, j in zip_longest(preorder_traversal(a), preorder_traversal(b)):
if i != j or type(i) != type(j):
if ((isinstance(i, UndefFunc) and isinstance(j, UndefFunc)) or
(isinstance(i, AppliedUndef) and isinstance(j, AppliedUndef))):
if i.class_key() != j.class_key():
return False
else:
return False
else:
return True
def _atomic(e, recursive=False):
"""Return atom-like quantities as far as substitution is
concerned: Derivatives, Functions and Symbols. Don't
return any 'atoms' that are inside such quantities unless
they also appear outside, too, unless `recursive` is True.
Examples
========
>>> from sympy import Derivative, Function, cos
>>> from sympy.abc import x, y
>>> from sympy.core.basic import _atomic
>>> f = Function('f')
>>> _atomic(x + y)
{x, y}
>>> _atomic(x + f(y))
{x, f(y)}
>>> _atomic(Derivative(f(x), x) + cos(x) + y)
{y, cos(x), Derivative(f(x), x)}
"""
from sympy import Derivative, Function, Symbol
pot = preorder_traversal(e)
seen = set()
if isinstance(e, Basic):
try:
free = e.free_symbols
except AttributeError:
return {e}
else:
return set()
atoms = set()
for p in pot:
if p in seen:
pot.skip()
continue
seen.add(p)
if isinstance(p, Symbol) and p in free:
atoms.add(p)
elif isinstance(p, (Derivative, Function)):
if not recursive:
pot.skip()
atoms.add(p)
return atoms
class preorder_traversal(Iterator):
"""
Do a pre-order traversal of a tree.
This iterator recursively yields nodes that it has visited in a pre-order
fashion. That is, it yields the current node then descends through the
tree breadth-first to yield all of a node's children's pre-order
traversal.
For an expression, the order of the traversal depends on the order of
.args, which in many cases can be arbitrary.
Parameters
==========
node : sympy expression
The expression to traverse.
keys : (default None) sort key(s)
The key(s) used to sort args of Basic objects. When None, args of Basic
objects are processed in arbitrary order. If key is defined, it will
be passed along to ordered() as the only key(s) to use to sort the
arguments; if ``key`` is simply True then the default keys of ordered
will be used.
Yields
======
subtree : sympy expression
All of the subtrees in the tree.
Examples
========
>>> from sympy import symbols
>>> from sympy.core.basic import preorder_traversal
>>> x, y, z = symbols('x y z')
The nodes are returned in the order that they are encountered unless key
is given; simply passing key=True will guarantee that the traversal is
unique.
>>> list(preorder_traversal((x + y)*z, keys=None)) # doctest: +SKIP
[z*(x + y), z, x + y, y, x]
>>> list(preorder_traversal((x + y)*z, keys=True))
[z*(x + y), z, x + y, x, y]
"""
def __init__(self, node, keys=None):
self._skip_flag = False
self._pt = self._preorder_traversal(node, keys)
def _preorder_traversal(self, node, keys):
yield node
if self._skip_flag:
self._skip_flag = False
return
if isinstance(node, Basic):
if not keys and hasattr(node, '_argset'):
# LatticeOp keeps args as a set. We should use this if we
# don't care about the order, to prevent unnecessary sorting.
args = node._argset
else:
args = node.args
if keys:
if keys != True:
args = ordered(args, keys, default=False)
else:
args = ordered(args)
for arg in args:
for subtree in self._preorder_traversal(arg, keys):
yield subtree
elif iterable(node):
for item in node:
for subtree in self._preorder_traversal(item, keys):
yield subtree
def skip(self):
"""
Skip yielding current node's (last yielded node's) subtrees.
Examples
========
>>> from sympy.core import symbols
>>> from sympy.core.basic import preorder_traversal
>>> x, y, z = symbols('x y z')
>>> pt = preorder_traversal((x+y*z)*z)
>>> for i in pt:
... print(i)
... if i == x+y*z:
... pt.skip()
z*(x + y*z)
z
x + y*z
"""
self._skip_flag = True
def __next__(self):
return next(self._pt)
def __iter__(self):
return self
def _make_find_query(query):
"""Convert the argument of Basic.find() into a callable"""
try:
query = sympify(query)
except SympifyError:
pass
if isinstance(query, type):
return lambda expr: isinstance(expr, query)
elif isinstance(query, Basic):
return lambda expr: expr.match(query) is not None
return query
|
3b6383421429619088f14a8e708551388214cd23099814bd5a4e211b256fbb8d
|
from __future__ import print_function, division
from .sympify import sympify, _sympify, SympifyError
from .basic import Basic, Atom
from .singleton import S
from .evalf import EvalfMixin, pure_complex
from .decorators import _sympifyit, call_highest_priority
from .cache import cacheit
from .compatibility import reduce, as_int, default_sort_key, range, Iterable
from mpmath.libmp import mpf_log, prec_to_dps
from collections import defaultdict
class Expr(Basic, EvalfMixin):
"""
Base class for algebraic expressions.
Everything that requires arithmetic operations to be defined
should subclass this class, instead of Basic (which should be
used only for argument storage and expression manipulation, i.e.
pattern matching, substitutions, etc).
See Also
========
sympy.core.basic.Basic
"""
__slots__ = []
is_scalar = True # self derivative is 1
@property
def _diff_wrt(self):
"""Return True if one can differentiate with respect to this
object, else False.
Subclasses such as Symbol, Function and Derivative return True
to enable derivatives wrt them. The implementation in Derivative
separates the Symbol and non-Symbol (_diff_wrt=True) variables and
temporarily converts the non-Symbols into Symbols when performing
the differentiation. By default, any object deriving from Expr
will behave like a scalar with self.diff(self) == 1. If this is
not desired then the object must also set `is_scalar = False` or
else define an _eval_derivative routine.
Note, see the docstring of Derivative for how this should work
mathematically. In particular, note that expr.subs(yourclass, Symbol)
should be well-defined on a structural level, or this will lead to
inconsistent results.
Examples
========
>>> from sympy import Expr
>>> e = Expr()
>>> e._diff_wrt
False
>>> class MyScalar(Expr):
... _diff_wrt = True
...
>>> MyScalar().diff(MyScalar())
1
>>> class MySymbol(Expr):
... _diff_wrt = True
... is_scalar = False
...
>>> MySymbol().diff(MySymbol())
Derivative(MySymbol(), MySymbol())
"""
return False
@cacheit
def sort_key(self, order=None):
coeff, expr = self.as_coeff_Mul()
if expr.is_Pow:
expr, exp = expr.args
else:
expr, exp = expr, S.One
if expr.is_Dummy:
args = (expr.sort_key(),)
elif expr.is_Atom:
args = (str(expr),)
else:
if expr.is_Add:
args = expr.as_ordered_terms(order=order)
elif expr.is_Mul:
args = expr.as_ordered_factors(order=order)
else:
args = expr.args
args = tuple(
[ default_sort_key(arg, order=order) for arg in args ])
args = (len(args), tuple(args))
exp = exp.sort_key(order=order)
return expr.class_key(), args, exp, coeff
# ***************
# * Arithmetics *
# ***************
# Expr and its sublcasses use _op_priority to determine which object
# passed to a binary special method (__mul__, etc.) will handle the
# operation. In general, the 'call_highest_priority' decorator will choose
# the object with the highest _op_priority to handle the call.
# Custom subclasses that want to define their own binary special methods
# should set an _op_priority value that is higher than the default.
#
# **NOTE**:
# This is a temporary fix, and will eventually be replaced with
# something better and more powerful. See issue 5510.
_op_priority = 10.0
def __pos__(self):
return self
def __neg__(self):
return Mul(S.NegativeOne, self)
def __abs__(self):
from sympy import Abs
return Abs(self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__radd__')
def __add__(self, other):
return Add(self, other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__add__')
def __radd__(self, other):
return Add(other, self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rsub__')
def __sub__(self, other):
return Add(self, -other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__sub__')
def __rsub__(self, other):
return Add(other, -self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmul__')
def __mul__(self, other):
return Mul(self, other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mul__')
def __rmul__(self, other):
return Mul(other, self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rpow__')
def _pow(self, other):
return Pow(self, other)
def __pow__(self, other, mod=None):
if mod is None:
return self._pow(other)
try:
_self, other, mod = as_int(self), as_int(other), as_int(mod)
if other >= 0:
return pow(_self, other, mod)
else:
from sympy.core.numbers import mod_inverse
return mod_inverse(pow(_self, -other, mod), mod)
except ValueError:
power = self._pow(other)
try:
return power%mod
except TypeError:
return NotImplemented
@_sympifyit('other', NotImplemented)
@call_highest_priority('__pow__')
def __rpow__(self, other):
return Pow(other, self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rdiv__')
def __div__(self, other):
return Mul(self, Pow(other, S.NegativeOne))
@_sympifyit('other', NotImplemented)
@call_highest_priority('__div__')
def __rdiv__(self, other):
return Mul(other, Pow(self, S.NegativeOne))
__truediv__ = __div__
__rtruediv__ = __rdiv__
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rmod__')
def __mod__(self, other):
return Mod(self, other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__mod__')
def __rmod__(self, other):
return Mod(other, self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rfloordiv__')
def __floordiv__(self, other):
from sympy.functions.elementary.integers import floor
return floor(self / other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__floordiv__')
def __rfloordiv__(self, other):
from sympy.functions.elementary.integers import floor
return floor(other / self)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__rdivmod__')
def __divmod__(self, other):
from sympy.functions.elementary.integers import floor
return floor(self / other), Mod(self, other)
@_sympifyit('other', NotImplemented)
@call_highest_priority('__divmod__')
def __rdivmod__(self, other):
from sympy.functions.elementary.integers import floor
return floor(other / self), Mod(other, self)
def __int__(self):
# Although we only need to round to the units position, we'll
# get one more digit so the extra testing below can be avoided
# unless the rounded value rounded to an integer, e.g. if an
# expression were equal to 1.9 and we rounded to the unit position
# we would get a 2 and would not know if this rounded up or not
# without doing a test (as done below). But if we keep an extra
# digit we know that 1.9 is not the same as 1 and there is no
# need for further testing: our int value is correct. If the value
# were 1.99, however, this would round to 2.0 and our int value is
# off by one. So...if our round value is the same as the int value
# (regardless of how much extra work we do to calculate extra decimal
# places) we need to test whether we are off by one.
from sympy import Dummy
if not self.is_number:
raise TypeError("can't convert symbols to int")
r = self.round(2)
if not r.is_Number:
raise TypeError("can't convert complex to int")
if r in (S.NaN, S.Infinity, S.NegativeInfinity):
raise TypeError("can't convert %s to int" % r)
i = int(r)
if not i:
return 0
# off-by-one check
if i == r and not (self - i).equals(0):
isign = 1 if i > 0 else -1
x = Dummy()
# in the following (self - i).evalf(2) will not always work while
# (self - r).evalf(2) and the use of subs does; if the test that
# was added when this comment was added passes, it might be safe
# to simply use sign to compute this rather than doing this by hand:
diff_sign = 1 if (self - x).evalf(2, subs={x: i}) > 0 else -1
if diff_sign != isign:
i -= isign
return i
__long__ = __int__
def __float__(self):
# Don't bother testing if it's a number; if it's not this is going
# to fail, and if it is we still need to check that it evalf'ed to
# a number.
result = self.evalf()
if result.is_Number:
return float(result)
if result.is_number and result.as_real_imag()[1]:
raise TypeError("can't convert complex to float")
raise TypeError("can't convert expression to float")
def __complex__(self):
result = self.evalf()
re, im = result.as_real_imag()
return complex(float(re), float(im))
def __ge__(self, other):
from sympy import GreaterThan
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
for me in (self, other):
if me.is_complex and me.is_real is False:
raise TypeError("Invalid comparison of complex %s" % me)
if me is S.NaN:
raise TypeError("Invalid NaN comparison")
n2 = _n2(self, other)
if n2 is not None:
return _sympify(n2 >= 0)
if self.is_real or other.is_real:
dif = self - other
if dif.is_nonnegative is not None and \
dif.is_nonnegative is not dif.is_negative:
return sympify(dif.is_nonnegative)
return GreaterThan(self, other, evaluate=False)
def __le__(self, other):
from sympy import LessThan
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
for me in (self, other):
if me.is_complex and me.is_real is False:
raise TypeError("Invalid comparison of complex %s" % me)
if me is S.NaN:
raise TypeError("Invalid NaN comparison")
n2 = _n2(self, other)
if n2 is not None:
return _sympify(n2 <= 0)
if self.is_real or other.is_real:
dif = self - other
if dif.is_nonpositive is not None and \
dif.is_nonpositive is not dif.is_positive:
return sympify(dif.is_nonpositive)
return LessThan(self, other, evaluate=False)
def __gt__(self, other):
from sympy import StrictGreaterThan
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
for me in (self, other):
if me.is_complex and me.is_real is False:
raise TypeError("Invalid comparison of complex %s" % me)
if me is S.NaN:
raise TypeError("Invalid NaN comparison")
n2 = _n2(self, other)
if n2 is not None:
return _sympify(n2 > 0)
if self.is_real or other.is_real:
dif = self - other
if dif.is_positive is not None and \
dif.is_positive is not dif.is_nonpositive:
return sympify(dif.is_positive)
return StrictGreaterThan(self, other, evaluate=False)
def __lt__(self, other):
from sympy import StrictLessThan
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
for me in (self, other):
if me.is_complex and me.is_real is False:
raise TypeError("Invalid comparison of complex %s" % me)
if me is S.NaN:
raise TypeError("Invalid NaN comparison")
n2 = _n2(self, other)
if n2 is not None:
return _sympify(n2 < 0)
if self.is_real or other.is_real:
dif = self - other
if dif.is_negative is not None and \
dif.is_negative is not dif.is_nonnegative:
return sympify(dif.is_negative)
return StrictLessThan(self, other, evaluate=False)
def __trunc__(self):
if not self.is_number:
raise TypeError("can't truncate symbols and expressions")
else:
return Integer(self)
@staticmethod
def _from_mpmath(x, prec):
from sympy import Float
if hasattr(x, "_mpf_"):
return Float._new(x._mpf_, prec)
elif hasattr(x, "_mpc_"):
re, im = x._mpc_
re = Float._new(re, prec)
im = Float._new(im, prec)*S.ImaginaryUnit
return re + im
else:
raise TypeError("expected mpmath number (mpf or mpc)")
@property
def is_number(self):
"""Returns True if ``self`` has no free symbols and no
undefined functions (AppliedUndef, to be precise). It will be
faster than ``if not self.free_symbols``, however, since
``is_number`` will fail as soon as it hits a free symbol
or undefined function.
Examples
========
>>> from sympy import log, Integral, cos, sin, pi
>>> from sympy.core.function import Function
>>> from sympy.abc import x
>>> f = Function('f')
>>> x.is_number
False
>>> f(1).is_number
False
>>> (2*x).is_number
False
>>> (2 + Integral(2, x)).is_number
False
>>> (2 + Integral(2, (x, 1, 2))).is_number
True
Not all numbers are Numbers in the SymPy sense:
>>> pi.is_number, pi.is_Number
(True, False)
If something is a number it should evaluate to a number with
real and imaginary parts that are Numbers; the result may not
be comparable, however, since the real and/or imaginary part
of the result may not have precision.
>>> cos(1).is_number and cos(1).is_comparable
True
>>> z = cos(1)**2 + sin(1)**2 - 1
>>> z.is_number
True
>>> z.is_comparable
False
See Also
========
sympy.core.basic.is_comparable
"""
return all(obj.is_number for obj in self.args)
def _random(self, n=None, re_min=-1, im_min=-1, re_max=1, im_max=1):
"""Return self evaluated, if possible, replacing free symbols with
random complex values, if necessary.
The random complex value for each free symbol is generated
by the random_complex_number routine giving real and imaginary
parts in the range given by the re_min, re_max, im_min, and im_max
values. The returned value is evaluated to a precision of n
(if given) else the maximum of 15 and the precision needed
to get more than 1 digit of precision. If the expression
could not be evaluated to a number, or could not be evaluated
to more than 1 digit of precision, then None is returned.
Examples
========
>>> from sympy import sqrt
>>> from sympy.abc import x, y
>>> x._random() # doctest: +SKIP
0.0392918155679172 + 0.916050214307199*I
>>> x._random(2) # doctest: +SKIP
-0.77 - 0.87*I
>>> (x + y/2)._random(2) # doctest: +SKIP
-0.57 + 0.16*I
>>> sqrt(2)._random(2)
1.4
See Also
========
sympy.utilities.randtest.random_complex_number
"""
free = self.free_symbols
prec = 1
if free:
from sympy.utilities.randtest import random_complex_number
a, c, b, d = re_min, re_max, im_min, im_max
reps = dict(list(zip(free, [random_complex_number(a, b, c, d, rational=True)
for zi in free])))
try:
nmag = abs(self.evalf(2, subs=reps))
except (ValueError, TypeError):
# if an out of range value resulted in evalf problems
# then return None -- XXX is there a way to know how to
# select a good random number for a given expression?
# e.g. when calculating n! negative values for n should not
# be used
return None
else:
reps = {}
nmag = abs(self.evalf(2))
if not hasattr(nmag, '_prec'):
# e.g. exp_polar(2*I*pi) doesn't evaluate but is_number is True
return None
if nmag._prec == 1:
# increase the precision up to the default maximum
# precision to see if we can get any significance
from mpmath.libmp.libintmath import giant_steps
from sympy.core.evalf import DEFAULT_MAXPREC as target
# evaluate
for prec in giant_steps(2, target):
nmag = abs(self.evalf(prec, subs=reps))
if nmag._prec != 1:
break
if nmag._prec != 1:
if n is None:
n = max(prec, 15)
return self.evalf(n, subs=reps)
# never got any significance
return None
def is_constant(self, *wrt, **flags):
"""Return True if self is constant, False if not, or None if
the constancy could not be determined conclusively.
If an expression has no free symbols then it is a constant. If
there are free symbols it is possible that the expression is a
constant, perhaps (but not necessarily) zero. To test such
expressions, two strategies are tried:
1) numerical evaluation at two random points. If two such evaluations
give two different values and the values have a precision greater than
1 then self is not constant. If the evaluations agree or could not be
obtained with any precision, no decision is made. The numerical testing
is done only if ``wrt`` is different than the free symbols.
2) differentiation with respect to variables in 'wrt' (or all free
symbols if omitted) to see if the expression is constant or not. This
will not always lead to an expression that is zero even though an
expression is constant (see added test in test_expr.py). If
all derivatives are zero then self is constant with respect to the
given symbols.
If neither evaluation nor differentiation can prove the expression is
constant, None is returned unless two numerical values happened to be
the same and the flag ``failing_number`` is True -- in that case the
numerical value will be returned.
If flag simplify=False is passed, self will not be simplified;
the default is True since self should be simplified before testing.
Examples
========
>>> from sympy import cos, sin, Sum, S, pi
>>> from sympy.abc import a, n, x, y
>>> x.is_constant()
False
>>> S(2).is_constant()
True
>>> Sum(x, (x, 1, 10)).is_constant()
True
>>> Sum(x, (x, 1, n)).is_constant()
False
>>> Sum(x, (x, 1, n)).is_constant(y)
True
>>> Sum(x, (x, 1, n)).is_constant(n)
False
>>> Sum(x, (x, 1, n)).is_constant(x)
True
>>> eq = a*cos(x)**2 + a*sin(x)**2 - a
>>> eq.is_constant()
True
>>> eq.subs({x: pi, a: 2}) == eq.subs({x: pi, a: 3}) == 0
True
>>> (0**x).is_constant()
False
>>> x.is_constant()
False
>>> (x**x).is_constant()
False
>>> one = cos(x)**2 + sin(x)**2
>>> one.is_constant()
True
>>> ((one - 1)**(x + 1)).is_constant() in (True, False) # could be 0 or 1
True
"""
simplify = flags.get('simplify', True)
if self.is_number:
return True
free = self.free_symbols
if not free:
return True # assume f(1) is some constant
# if we are only interested in some symbols and they are not in the
# free symbols then this expression is constant wrt those symbols
wrt = set(wrt)
if wrt and not wrt & free:
return True
wrt = wrt or free
# simplify unless this has already been done
expr = self
if simplify:
expr = expr.simplify()
# is_zero should be a quick assumptions check; it can be wrong for
# numbers (see test_is_not_constant test), giving False when it
# shouldn't, but hopefully it will never give True unless it is sure.
if expr.is_zero:
return True
# try numerical evaluation to see if we get two different values
failing_number = None
if wrt == free:
# try 0 (for a) and 1 (for b)
try:
a = expr.subs(list(zip(free, [0]*len(free))),
simultaneous=True)
if a is S.NaN:
# evaluation may succeed when substitution fails
a = expr._random(None, 0, 0, 0, 0)
except ZeroDivisionError:
a = None
if a is not None and a is not S.NaN:
try:
b = expr.subs(list(zip(free, [1]*len(free))),
simultaneous=True)
if b is S.NaN:
# evaluation may succeed when substitution fails
b = expr._random(None, 1, 0, 1, 0)
except ZeroDivisionError:
b = None
if b is not None and b is not S.NaN and b.equals(a) is False:
return False
# try random real
b = expr._random(None, -1, 0, 1, 0)
if b is not None and b is not S.NaN and b.equals(a) is False:
return False
# try random complex
b = expr._random()
if b is not None and b is not S.NaN:
if b.equals(a) is False:
return False
failing_number = a if a.is_number else b
# now we will test each wrt symbol (or all free symbols) to see if the
# expression depends on them or not using differentiation. This is
# not sufficient for all expressions, however, so we don't return
# False if we get a derivative other than 0 with free symbols.
for w in wrt:
deriv = expr.diff(w)
if simplify:
deriv = deriv.simplify()
if deriv != 0:
if not (pure_complex(deriv, or_real=True)):
if flags.get('failing_number', False):
return failing_number
elif deriv.free_symbols:
# dead line provided _random returns None in such cases
return None
return False
return True
def equals(self, other, failing_expression=False):
"""Return True if self == other, False if it doesn't, or None. If
failing_expression is True then the expression which did not simplify
to a 0 will be returned instead of None.
If ``self`` is a Number (or complex number) that is not zero, then
the result is False.
If ``self`` is a number and has not evaluated to zero, evalf will be
used to test whether the expression evaluates to zero. If it does so
and the result has significance (i.e. the precision is either -1, for
a Rational result, or is greater than 1) then the evalf value will be
used to return True or False.
"""
from sympy.simplify.simplify import nsimplify, simplify
from sympy.solvers.solveset import solveset
from sympy.polys.polyerrors import NotAlgebraic
from sympy.polys.numberfields import minimal_polynomial
other = sympify(other)
if self == other:
return True
# they aren't the same so see if we can make the difference 0;
# don't worry about doing simplification steps one at a time
# because if the expression ever goes to 0 then the subsequent
# simplification steps that are done will be very fast.
diff = factor_terms(simplify(self - other), radical=True)
if not diff:
return True
if not diff.has(Add, Mod):
# if there is no expanding to be done after simplifying
# then this can't be a zero
return False
constant = diff.is_constant(simplify=False, failing_number=True)
if constant is False:
return False
if constant is None and (diff.free_symbols or not diff.is_number):
# e.g. unless the right simplification is done, a symbolic
# zero is possible (see expression of issue 6829: without
# simplification constant will be None).
return
if constant is True:
ndiff = diff._random()
if ndiff:
return False
# sometimes we can use a simplified result to give a clue as to
# what the expression should be; if the expression is *not* zero
# then we should have been able to compute that and so now
# we can just consider the cases where the approximation appears
# to be zero -- we try to prove it via minimal_polynomial.
if diff.is_number:
approx = diff.nsimplify()
if not approx:
# try to prove via self-consistency
surds = [s for s in diff.atoms(Pow) if s.args[0].is_Integer]
# it seems to work better to try big ones first
surds.sort(key=lambda x: -x.args[0])
for s in surds:
try:
# simplify is False here -- this expression has already
# been identified as being hard to identify as zero;
# we will handle the checking ourselves using nsimplify
# to see if we are in the right ballpark or not and if so
# *then* the simplification will be attempted.
if s.is_Symbol:
sol = list(solveset(diff, s))
else:
sol = [s]
if sol:
if s in sol:
return True
if s.is_real:
if any(nsimplify(si, [s]) == s and simplify(si) == s
for si in sol):
return True
except NotImplementedError:
pass
# try to prove with minimal_polynomial but know when
# *not* to use this or else it can take a long time. e.g. issue 8354
if True: # change True to condition that assures non-hang
try:
mp = minimal_polynomial(diff)
if mp.is_Symbol:
return True
return False
except (NotAlgebraic, NotImplementedError):
pass
# diff has not simplified to zero; constant is either None, True
# or the number with significance (prec != 1) that was randomly
# calculated twice as the same value.
if constant not in (True, None) and constant != 0:
return False
if failing_expression:
return diff
return None
def _eval_is_positive(self):
from sympy.polys.numberfields import minimal_polynomial
from sympy.polys.polyerrors import NotAlgebraic
if self.is_number:
if self.is_real is False:
return False
try:
# check to see that we can get a value
n2 = self._eval_evalf(2)
if n2 is None:
raise AttributeError
if n2._prec == 1: # no significance
raise AttributeError
if n2 == S.NaN:
raise AttributeError
except (AttributeError, ValueError):
return None
n, i = self.evalf(2).as_real_imag()
if not i.is_Number or not n.is_Number:
return False
if n._prec != 1 and i._prec != 1:
return bool(not i and n > 0)
elif n._prec == 1 and (not i or i._prec == 1) and \
self.is_algebraic and not self.has(Function):
try:
if minimal_polynomial(self).is_Symbol:
return False
except (NotAlgebraic, NotImplementedError):
pass
def _eval_is_negative(self):
from sympy.polys.numberfields import minimal_polynomial
from sympy.polys.polyerrors import NotAlgebraic
if self.is_number:
if self.is_real is False:
return False
try:
# check to see that we can get a value
n2 = self._eval_evalf(2)
if n2 is None:
raise AttributeError
if n2._prec == 1: # no significance
raise AttributeError
if n2 == S.NaN:
raise AttributeError
except (AttributeError, ValueError):
return None
n, i = self.evalf(2).as_real_imag()
if not i.is_Number or not n.is_Number:
return False
if n._prec != 1 and i._prec != 1:
return bool(not i and n < 0)
elif n._prec == 1 and (not i or i._prec == 1) and \
self.is_algebraic and not self.has(Function):
try:
if minimal_polynomial(self).is_Symbol:
return False
except (NotAlgebraic, NotImplementedError):
pass
def _eval_interval(self, x, a, b):
"""
Returns evaluation over an interval. For most functions this is:
self.subs(x, b) - self.subs(x, a),
possibly using limit() if NaN is returned from subs, or if
singularities are found between a and b.
If b or a is None, it only evaluates -self.subs(x, a) or self.subs(b, x),
respectively.
"""
from sympy.series import limit, Limit
from sympy.solvers.solveset import solveset
from sympy.sets.sets import Interval
from sympy.functions.elementary.exponential import log
from sympy.calculus.util import AccumBounds
if (a is None and b is None):
raise ValueError('Both interval ends cannot be None.')
if a == b:
return 0
if a is None:
A = 0
else:
A = self.subs(x, a)
if A.has(S.NaN, S.Infinity, S.NegativeInfinity, S.ComplexInfinity, AccumBounds):
if (a < b) != False:
A = limit(self, x, a,"+")
else:
A = limit(self, x, a,"-")
if A is S.NaN:
return A
if isinstance(A, Limit):
raise NotImplementedError("Could not compute limit")
if b is None:
B = 0
else:
B = self.subs(x, b)
if B.has(S.NaN, S.Infinity, S.NegativeInfinity, S.ComplexInfinity, AccumBounds):
if (a < b) != False:
B = limit(self, x, b,"-")
else:
B = limit(self, x, b,"+")
if isinstance(B, Limit):
raise NotImplementedError("Could not compute limit")
if (a and b) is None:
return B - A
value = B - A
if a.is_comparable and b.is_comparable:
if a < b:
domain = Interval(a, b)
else:
domain = Interval(b, a)
# check the singularities of self within the interval
# if singularities is a ConditionSet (not iterable), catch the exception and pass
singularities = solveset(self.cancel().as_numer_denom()[1], x,
domain=domain)
for logterm in self.atoms(log):
singularities = singularities | solveset(logterm.args[0], x,
domain=domain)
try:
for s in singularities:
if value is S.NaN:
# no need to keep adding, it will stay NaN
break
if not s.is_comparable:
continue
if (a < s) == (s < b) == True:
value += -limit(self, x, s, "+") + limit(self, x, s, "-")
elif (b < s) == (s < a) == True:
value += limit(self, x, s, "+") - limit(self, x, s, "-")
except TypeError:
pass
return value
def _eval_power(self, other):
# subclass to compute self**other for cases when
# other is not NaN, 0, or 1
return None
def _eval_conjugate(self):
if self.is_real:
return self
elif self.is_imaginary:
return -self
def conjugate(self):
from sympy.functions.elementary.complexes import conjugate as c
return c(self)
def _eval_transpose(self):
from sympy.functions.elementary.complexes import conjugate
if self.is_complex:
return self
elif self.is_hermitian:
return conjugate(self)
elif self.is_antihermitian:
return -conjugate(self)
def transpose(self):
from sympy.functions.elementary.complexes import transpose
return transpose(self)
def _eval_adjoint(self):
from sympy.functions.elementary.complexes import conjugate, transpose
if self.is_hermitian:
return self
elif self.is_antihermitian:
return -self
obj = self._eval_conjugate()
if obj is not None:
return transpose(obj)
obj = self._eval_transpose()
if obj is not None:
return conjugate(obj)
def adjoint(self):
from sympy.functions.elementary.complexes import adjoint
return adjoint(self)
@classmethod
def _parse_order(cls, order):
"""Parse and configure the ordering of terms. """
from sympy.polys.orderings import monomial_key
try:
reverse = order.startswith('rev-')
except AttributeError:
reverse = False
else:
if reverse:
order = order[4:]
monom_key = monomial_key(order)
def neg(monom):
result = []
for m in monom:
if isinstance(m, tuple):
result.append(neg(m))
else:
result.append(-m)
return tuple(result)
def key(term):
_, ((re, im), monom, ncpart) = term
monom = neg(monom_key(monom))
ncpart = tuple([e.sort_key(order=order) for e in ncpart])
coeff = ((bool(im), im), (re, im))
return monom, ncpart, coeff
return key, reverse
def as_ordered_factors(self, order=None):
"""Return list of ordered factors (if Mul) else [self]."""
return [self]
def as_ordered_terms(self, order=None, data=False):
"""
Transform an expression to an ordered list of terms.
Examples
========
>>> from sympy import sin, cos
>>> from sympy.abc import x
>>> (sin(x)**2*cos(x) + sin(x)**2 + 1).as_ordered_terms()
[sin(x)**2*cos(x), sin(x)**2, 1]
"""
key, reverse = self._parse_order(order)
terms, gens = self.as_terms()
if not any(term.is_Order for term, _ in terms):
ordered = sorted(terms, key=key, reverse=reverse)
else:
_terms, _order = [], []
for term, repr in terms:
if not term.is_Order:
_terms.append((term, repr))
else:
_order.append((term, repr))
ordered = sorted(_terms, key=key, reverse=True) \
+ sorted(_order, key=key, reverse=True)
if data:
return ordered, gens
else:
return [term for term, _ in ordered]
def as_terms(self):
"""Transform an expression to a list of terms. """
from .add import Add
from .mul import Mul
from .exprtools import decompose_power
gens, terms = set([]), []
for term in Add.make_args(self):
coeff, _term = term.as_coeff_Mul()
coeff = complex(coeff)
cpart, ncpart = {}, []
if _term is not S.One:
for factor in Mul.make_args(_term):
if factor.is_number:
try:
coeff *= complex(factor)
except (TypeError, ValueError):
pass
else:
continue
if factor.is_commutative:
base, exp = decompose_power(factor)
cpart[base] = exp
gens.add(base)
else:
ncpart.append(factor)
coeff = coeff.real, coeff.imag
ncpart = tuple(ncpart)
terms.append((term, (coeff, cpart, ncpart)))
gens = sorted(gens, key=default_sort_key)
k, indices = len(gens), {}
for i, g in enumerate(gens):
indices[g] = i
result = []
for term, (coeff, cpart, ncpart) in terms:
monom = [0]*k
for base, exp in cpart.items():
monom[indices[base]] = exp
result.append((term, (coeff, tuple(monom), ncpart)))
return result, gens
def removeO(self):
"""Removes the additive O(..) symbol if there is one"""
return self
def getO(self):
"""Returns the additive O(..) symbol if there is one, else None."""
return None
def getn(self):
"""
Returns the order of the expression.
The order is determined either from the O(...) term. If there
is no O(...) term, it returns None.
Examples
========
>>> from sympy import O
>>> from sympy.abc import x
>>> (1 + x + O(x**2)).getn()
2
>>> (1 + x).getn()
"""
from sympy import Dummy, Symbol
o = self.getO()
if o is None:
return None
elif o.is_Order:
o = o.expr
if o is S.One:
return S.Zero
if o.is_Symbol:
return S.One
if o.is_Pow:
return o.args[1]
if o.is_Mul: # x**n*log(x)**n or x**n/log(x)**n
for oi in o.args:
if oi.is_Symbol:
return S.One
if oi.is_Pow:
syms = oi.atoms(Symbol)
if len(syms) == 1:
x = syms.pop()
oi = oi.subs(x, Dummy('x', positive=True))
if oi.base.is_Symbol and oi.exp.is_Rational:
return abs(oi.exp)
raise NotImplementedError('not sure of order of %s' % o)
def count_ops(self, visual=None):
"""wrapper for count_ops that returns the operation count."""
from .function import count_ops
return count_ops(self, visual)
def args_cnc(self, cset=False, warn=True, split_1=True):
"""Return [commutative factors, non-commutative factors] of self.
self is treated as a Mul and the ordering of the factors is maintained.
If ``cset`` is True the commutative factors will be returned in a set.
If there were repeated factors (as may happen with an unevaluated Mul)
then an error will be raised unless it is explicitly suppressed by
setting ``warn`` to False.
Note: -1 is always separated from a Number unless split_1 is False.
>>> from sympy import symbols, oo
>>> A, B = symbols('A B', commutative=0)
>>> x, y = symbols('x y')
>>> (-2*x*y).args_cnc()
[[-1, 2, x, y], []]
>>> (-2.5*x).args_cnc()
[[-1, 2.5, x], []]
>>> (-2*x*A*B*y).args_cnc()
[[-1, 2, x, y], [A, B]]
>>> (-2*x*A*B*y).args_cnc(split_1=False)
[[-2, x, y], [A, B]]
>>> (-2*x*y).args_cnc(cset=True)
[{-1, 2, x, y}, []]
The arg is always treated as a Mul:
>>> (-2 + x + A).args_cnc()
[[], [x - 2 + A]]
>>> (-oo).args_cnc() # -oo is a singleton
[[-1, oo], []]
"""
if self.is_Mul:
args = list(self.args)
else:
args = [self]
for i, mi in enumerate(args):
if not mi.is_commutative:
c = args[:i]
nc = args[i:]
break
else:
c = args
nc = []
if c and split_1 and (
c[0].is_Number and
c[0].is_negative and
c[0] is not S.NegativeOne):
c[:1] = [S.NegativeOne, -c[0]]
if cset:
clen = len(c)
c = set(c)
if clen and warn and len(c) != clen:
raise ValueError('repeated commutative arguments: %s' %
[ci for ci in c if list(self.args).count(ci) > 1])
return [c, nc]
def coeff(self, x, n=1, right=False):
"""
Returns the coefficient from the term(s) containing ``x**n``. If ``n``
is zero then all terms independent of ``x`` will be returned.
When ``x`` is noncommutative, the coefficient to the left (default) or
right of ``x`` can be returned. The keyword 'right' is ignored when
``x`` is commutative.
See Also
========
as_coefficient: separate the expression into a coefficient and factor
as_coeff_Add: separate the additive constant from an expression
as_coeff_Mul: separate the multiplicative constant from an expression
as_independent: separate x-dependent terms/factors from others
sympy.polys.polytools.coeff_monomial: efficiently find the single coefficient of a monomial in Poly
sympy.polys.polytools.nth: like coeff_monomial but powers of monomial terms are used
Examples
========
>>> from sympy import symbols
>>> from sympy.abc import x, y, z
You can select terms that have an explicit negative in front of them:
>>> (-x + 2*y).coeff(-1)
x
>>> (x - 2*y).coeff(-1)
2*y
You can select terms with no Rational coefficient:
>>> (x + 2*y).coeff(1)
x
>>> (3 + 2*x + 4*x**2).coeff(1)
0
You can select terms independent of x by making n=0; in this case
expr.as_independent(x)[0] is returned (and 0 will be returned instead
of None):
>>> (3 + 2*x + 4*x**2).coeff(x, 0)
3
>>> eq = ((x + 1)**3).expand() + 1
>>> eq
x**3 + 3*x**2 + 3*x + 2
>>> [eq.coeff(x, i) for i in reversed(range(4))]
[1, 3, 3, 2]
>>> eq -= 2
>>> [eq.coeff(x, i) for i in reversed(range(4))]
[1, 3, 3, 0]
You can select terms that have a numerical term in front of them:
>>> (-x - 2*y).coeff(2)
-y
>>> from sympy import sqrt
>>> (x + sqrt(2)*x).coeff(sqrt(2))
x
The matching is exact:
>>> (3 + 2*x + 4*x**2).coeff(x)
2
>>> (3 + 2*x + 4*x**2).coeff(x**2)
4
>>> (3 + 2*x + 4*x**2).coeff(x**3)
0
>>> (z*(x + y)**2).coeff((x + y)**2)
z
>>> (z*(x + y)**2).coeff(x + y)
0
In addition, no factoring is done, so 1 + z*(1 + y) is not obtained
from the following:
>>> (x + z*(x + x*y)).coeff(x)
1
If such factoring is desired, factor_terms can be used first:
>>> from sympy import factor_terms
>>> factor_terms(x + z*(x + x*y)).coeff(x)
z*(y + 1) + 1
>>> n, m, o = symbols('n m o', commutative=False)
>>> n.coeff(n)
1
>>> (3*n).coeff(n)
3
>>> (n*m + m*n*m).coeff(n) # = (1 + m)*n*m
1 + m
>>> (n*m + m*n*m).coeff(n, right=True) # = (1 + m)*n*m
m
If there is more than one possible coefficient 0 is returned:
>>> (n*m + m*n).coeff(n)
0
If there is only one possible coefficient, it is returned:
>>> (n*m + x*m*n).coeff(m*n)
x
>>> (n*m + x*m*n).coeff(m*n, right=1)
1
"""
x = sympify(x)
if not isinstance(x, Basic):
return S.Zero
n = as_int(n)
if not x:
return S.Zero
if x == self:
if n == 1:
return S.One
return S.Zero
if x is S.One:
co = [a for a in Add.make_args(self)
if a.as_coeff_Mul()[0] is S.One]
if not co:
return S.Zero
return Add(*co)
if n == 0:
if x.is_Add and self.is_Add:
c = self.coeff(x, right=right)
if not c:
return S.Zero
if not right:
return self - Add(*[a*x for a in Add.make_args(c)])
return self - Add(*[x*a for a in Add.make_args(c)])
return self.as_independent(x, as_Add=True)[0]
# continue with the full method, looking for this power of x:
x = x**n
def incommon(l1, l2):
if not l1 or not l2:
return []
n = min(len(l1), len(l2))
for i in range(n):
if l1[i] != l2[i]:
return l1[:i]
return l1[:]
def find(l, sub, first=True):
""" Find where list sub appears in list l. When ``first`` is True
the first occurrence from the left is returned, else the last
occurrence is returned. Return None if sub is not in l.
>> l = range(5)*2
>> find(l, [2, 3])
2
>> find(l, [2, 3], first=0)
7
>> find(l, [2, 4])
None
"""
if not sub or not l or len(sub) > len(l):
return None
n = len(sub)
if not first:
l.reverse()
sub.reverse()
for i in range(0, len(l) - n + 1):
if all(l[i + j] == sub[j] for j in range(n)):
break
else:
i = None
if not first:
l.reverse()
sub.reverse()
if i is not None and not first:
i = len(l) - (i + n)
return i
co = []
args = Add.make_args(self)
self_c = self.is_commutative
x_c = x.is_commutative
if self_c and not x_c:
return S.Zero
if self_c:
xargs = x.args_cnc(cset=True, warn=False)[0]
for a in args:
margs = a.args_cnc(cset=True, warn=False)[0]
if len(xargs) > len(margs):
continue
resid = margs.difference(xargs)
if len(resid) + len(xargs) == len(margs):
co.append(Mul(*resid))
if co == []:
return S.Zero
elif co:
return Add(*co)
elif x_c:
xargs = x.args_cnc(cset=True, warn=False)[0]
for a in args:
margs, nc = a.args_cnc(cset=True)
if len(xargs) > len(margs):
continue
resid = margs.difference(xargs)
if len(resid) + len(xargs) == len(margs):
co.append(Mul(*(list(resid) + nc)))
if co == []:
return S.Zero
elif co:
return Add(*co)
else: # both nc
xargs, nx = x.args_cnc(cset=True)
# find the parts that pass the commutative terms
for a in args:
margs, nc = a.args_cnc(cset=True)
if len(xargs) > len(margs):
continue
resid = margs.difference(xargs)
if len(resid) + len(xargs) == len(margs):
co.append((resid, nc))
# now check the non-comm parts
if not co:
return S.Zero
if all(n == co[0][1] for r, n in co):
ii = find(co[0][1], nx, right)
if ii is not None:
if not right:
return Mul(Add(*[Mul(*r) for r, c in co]), Mul(*co[0][1][:ii]))
else:
return Mul(*co[0][1][ii + len(nx):])
beg = reduce(incommon, (n[1] for n in co))
if beg:
ii = find(beg, nx, right)
if ii is not None:
if not right:
gcdc = co[0][0]
for i in range(1, len(co)):
gcdc = gcdc.intersection(co[i][0])
if not gcdc:
break
return Mul(*(list(gcdc) + beg[:ii]))
else:
m = ii + len(nx)
return Add(*[Mul(*(list(r) + n[m:])) for r, n in co])
end = list(reversed(
reduce(incommon, (list(reversed(n[1])) for n in co))))
if end:
ii = find(end, nx, right)
if ii is not None:
if not right:
return Add(*[Mul(*(list(r) + n[:-len(end) + ii])) for r, n in co])
else:
return Mul(*end[ii + len(nx):])
# look for single match
hit = None
for i, (r, n) in enumerate(co):
ii = find(n, nx, right)
if ii is not None:
if not hit:
hit = ii, r, n
else:
break
else:
if hit:
ii, r, n = hit
if not right:
return Mul(*(list(r) + n[:ii]))
else:
return Mul(*n[ii + len(nx):])
return S.Zero
def as_expr(self, *gens):
"""
Convert a polynomial to a SymPy expression.
Examples
========
>>> from sympy import sin
>>> from sympy.abc import x, y
>>> f = (x**2 + x*y).as_poly(x, y)
>>> f.as_expr()
x**2 + x*y
>>> sin(x).as_expr()
sin(x)
"""
return self
def as_coefficient(self, expr):
"""
Extracts symbolic coefficient at the given expression. In
other words, this functions separates 'self' into the product
of 'expr' and 'expr'-free coefficient. If such separation
is not possible it will return None.
Examples
========
>>> from sympy import E, pi, sin, I, Poly
>>> from sympy.abc import x
>>> E.as_coefficient(E)
1
>>> (2*E).as_coefficient(E)
2
>>> (2*sin(E)*E).as_coefficient(E)
Two terms have E in them so a sum is returned. (If one were
desiring the coefficient of the term exactly matching E then
the constant from the returned expression could be selected.
Or, for greater precision, a method of Poly can be used to
indicate the desired term from which the coefficient is
desired.)
>>> (2*E + x*E).as_coefficient(E)
x + 2
>>> _.args[0] # just want the exact match
2
>>> p = Poly(2*E + x*E); p
Poly(x*E + 2*E, x, E, domain='ZZ')
>>> p.coeff_monomial(E)
2
>>> p.nth(0, 1)
2
Since the following cannot be written as a product containing
E as a factor, None is returned. (If the coefficient ``2*x`` is
desired then the ``coeff`` method should be used.)
>>> (2*E*x + x).as_coefficient(E)
>>> (2*E*x + x).coeff(E)
2*x
>>> (E*(x + 1) + x).as_coefficient(E)
>>> (2*pi*I).as_coefficient(pi*I)
2
>>> (2*I).as_coefficient(pi*I)
See Also
========
coeff: return sum of terms have a given factor
as_coeff_Add: separate the additive constant from an expression
as_coeff_Mul: separate the multiplicative constant from an expression
as_independent: separate x-dependent terms/factors from others
sympy.polys.polytools.coeff_monomial: efficiently find the single coefficient of a monomial in Poly
sympy.polys.polytools.nth: like coeff_monomial but powers of monomial terms are used
"""
r = self.extract_multiplicatively(expr)
if r and not r.has(expr):
return r
def as_independent(self, *deps, **hint):
"""
A mostly naive separation of a Mul or Add into arguments that are not
are dependent on deps. To obtain as complete a separation of variables
as possible, use a separation method first, e.g.:
* separatevars() to change Mul, Add and Pow (including exp) into Mul
* .expand(mul=True) to change Add or Mul into Add
* .expand(log=True) to change log expr into an Add
The only non-naive thing that is done here is to respect noncommutative
ordering of variables and to always return (0, 0) for `self` of zero
regardless of hints.
For nonzero `self`, the returned tuple (i, d) has the
following interpretation:
* i will has no variable that appears in deps
* d will either have terms that contain variables that are in deps, or
be equal to 0 (when self is an Add) or 1 (when self is a Mul)
* if self is an Add then self = i + d
* if self is a Mul then self = i*d
* otherwise (self, S.One) or (S.One, self) is returned.
To force the expression to be treated as an Add, use the hint as_Add=True
Examples
========
-- self is an Add
>>> from sympy import sin, cos, exp
>>> from sympy.abc import x, y, z
>>> (x + x*y).as_independent(x)
(0, x*y + x)
>>> (x + x*y).as_independent(y)
(x, x*y)
>>> (2*x*sin(x) + y + x + z).as_independent(x)
(y + z, 2*x*sin(x) + x)
>>> (2*x*sin(x) + y + x + z).as_independent(x, y)
(z, 2*x*sin(x) + x + y)
-- self is a Mul
>>> (x*sin(x)*cos(y)).as_independent(x)
(cos(y), x*sin(x))
non-commutative terms cannot always be separated out when self is a Mul
>>> from sympy import symbols
>>> n1, n2, n3 = symbols('n1 n2 n3', commutative=False)
>>> (n1 + n1*n2).as_independent(n2)
(n1, n1*n2)
>>> (n2*n1 + n1*n2).as_independent(n2)
(0, n1*n2 + n2*n1)
>>> (n1*n2*n3).as_independent(n1)
(1, n1*n2*n3)
>>> (n1*n2*n3).as_independent(n2)
(n1, n2*n3)
>>> ((x-n1)*(x-y)).as_independent(x)
(1, (x - y)*(x - n1))
-- self is anything else:
>>> (sin(x)).as_independent(x)
(1, sin(x))
>>> (sin(x)).as_independent(y)
(sin(x), 1)
>>> exp(x+y).as_independent(x)
(1, exp(x + y))
-- force self to be treated as an Add:
>>> (3*x).as_independent(x, as_Add=True)
(0, 3*x)
-- force self to be treated as a Mul:
>>> (3+x).as_independent(x, as_Add=False)
(1, x + 3)
>>> (-3+x).as_independent(x, as_Add=False)
(1, x - 3)
Note how the below differs from the above in making the
constant on the dep term positive.
>>> (y*(-3+x)).as_independent(x)
(y, x - 3)
-- use .as_independent() for true independence testing instead
of .has(). The former considers only symbols in the free
symbols while the latter considers all symbols
>>> from sympy import Integral
>>> I = Integral(x, (x, 1, 2))
>>> I.has(x)
True
>>> x in I.free_symbols
False
>>> I.as_independent(x) == (I, 1)
True
>>> (I + x).as_independent(x) == (I, x)
True
Note: when trying to get independent terms, a separation method
might need to be used first. In this case, it is important to keep
track of what you send to this routine so you know how to interpret
the returned values
>>> from sympy import separatevars, log
>>> separatevars(exp(x+y)).as_independent(x)
(exp(y), exp(x))
>>> (x + x*y).as_independent(y)
(x, x*y)
>>> separatevars(x + x*y).as_independent(y)
(x, y + 1)
>>> (x*(1 + y)).as_independent(y)
(x, y + 1)
>>> (x*(1 + y)).expand(mul=True).as_independent(y)
(x, x*y)
>>> a, b=symbols('a b', positive=True)
>>> (log(a*b).expand(log=True)).as_independent(b)
(log(a), log(b))
See Also
========
.separatevars(), .expand(log=True), Add.as_two_terms(),
Mul.as_two_terms(), .as_coeff_add(), .as_coeff_mul()
"""
from .symbol import Symbol
from .add import _unevaluated_Add
from .mul import _unevaluated_Mul
from sympy.utilities.iterables import sift
if self.is_zero:
return S.Zero, S.Zero
func = self.func
if hint.get('as_Add', isinstance(self, Add) ):
want = Add
else:
want = Mul
# sift out deps into symbolic and other and ignore
# all symbols but those that are in the free symbols
sym = set()
other = []
for d in deps:
if isinstance(d, Symbol): # Symbol.is_Symbol is True
sym.add(d)
else:
other.append(d)
def has(e):
"""return the standard has() if there are no literal symbols, else
check to see that symbol-deps are in the free symbols."""
has_other = e.has(*other)
if not sym:
return has_other
return has_other or e.has(*(e.free_symbols & sym))
if (want is not func or
func is not Add and func is not Mul):
if has(self):
return (want.identity, self)
else:
return (self, want.identity)
else:
if func is Add:
args = list(self.args)
else:
args, nc = self.args_cnc()
d = sift(args, lambda x: has(x))
depend = d[True]
indep = d[False]
if func is Add: # all terms were treated as commutative
return (Add(*indep), _unevaluated_Add(*depend))
else: # handle noncommutative by stopping at first dependent term
for i, n in enumerate(nc):
if has(n):
depend.extend(nc[i:])
break
indep.append(n)
return Mul(*indep), (
Mul(*depend, evaluate=False) if nc else
_unevaluated_Mul(*depend))
def as_real_imag(self, deep=True, **hints):
"""Performs complex expansion on 'self' and returns a tuple
containing collected both real and imaginary parts. This
method can't be confused with re() and im() functions,
which does not perform complex expansion at evaluation.
However it is possible to expand both re() and im()
functions and get exactly the same results as with
a single call to this function.
>>> from sympy import symbols, I
>>> x, y = symbols('x,y', real=True)
>>> (x + y*I).as_real_imag()
(x, y)
>>> from sympy.abc import z, w
>>> (z + w*I).as_real_imag()
(re(z) - im(w), re(w) + im(z))
"""
from sympy import im, re
if hints.get('ignore') == self:
return None
else:
return (re(self), im(self))
def as_powers_dict(self):
"""Return self as a dictionary of factors with each factor being
treated as a power. The keys are the bases of the factors and the
values, the corresponding exponents. The resulting dictionary should
be used with caution if the expression is a Mul and contains non-
commutative factors since the order that they appeared will be lost in
the dictionary.
See Also
========
as_ordered_factors: An alternative for noncommutative applications,
returning an ordered list of factors.
args_cnc: Similar to as_ordered_factors, but guarantees separation
of commutative and noncommutative factors.
"""
d = defaultdict(int)
d.update(dict([self.as_base_exp()]))
return d
def as_coefficients_dict(self):
"""Return a dictionary mapping terms to their Rational coefficient.
Since the dictionary is a defaultdict, inquiries about terms which
were not present will return a coefficient of 0. If an expression is
not an Add it is considered to have a single term.
Examples
========
>>> from sympy.abc import a, x
>>> (3*x + a*x + 4).as_coefficients_dict()
{1: 4, x: 3, a*x: 1}
>>> _[a]
0
>>> (3*a*x).as_coefficients_dict()
{a*x: 3}
"""
c, m = self.as_coeff_Mul()
if not c.is_Rational:
c = S.One
m = self
d = defaultdict(int)
d.update({m: c})
return d
def as_base_exp(self):
# a -> b ** e
return self, S.One
def as_coeff_mul(self, *deps, **kwargs):
"""Return the tuple (c, args) where self is written as a Mul, ``m``.
c should be a Rational multiplied by any factors of the Mul that are
independent of deps.
args should be a tuple of all other factors of m; args is empty
if self is a Number or if self is independent of deps (when given).
This should be used when you don't know if self is a Mul or not but
you want to treat self as a Mul or if you want to process the
individual arguments of the tail of self as a Mul.
- if you know self is a Mul and want only the head, use self.args[0];
- if you don't want to process the arguments of the tail but need the
tail then use self.as_two_terms() which gives the head and tail;
- if you want to split self into an independent and dependent parts
use ``self.as_independent(*deps)``
>>> from sympy import S
>>> from sympy.abc import x, y
>>> (S(3)).as_coeff_mul()
(3, ())
>>> (3*x*y).as_coeff_mul()
(3, (x, y))
>>> (3*x*y).as_coeff_mul(x)
(3*y, (x,))
>>> (3*y).as_coeff_mul(x)
(3*y, ())
"""
if deps:
if not self.has(*deps):
return self, tuple()
return S.One, (self,)
def as_coeff_add(self, *deps):
"""Return the tuple (c, args) where self is written as an Add, ``a``.
c should be a Rational added to any terms of the Add that are
independent of deps.
args should be a tuple of all other terms of ``a``; args is empty
if self is a Number or if self is independent of deps (when given).
This should be used when you don't know if self is an Add or not but
you want to treat self as an Add or if you want to process the
individual arguments of the tail of self as an Add.
- if you know self is an Add and want only the head, use self.args[0];
- if you don't want to process the arguments of the tail but need the
tail then use self.as_two_terms() which gives the head and tail.
- if you want to split self into an independent and dependent parts
use ``self.as_independent(*deps)``
>>> from sympy import S
>>> from sympy.abc import x, y
>>> (S(3)).as_coeff_add()
(3, ())
>>> (3 + x).as_coeff_add()
(3, (x,))
>>> (3 + x + y).as_coeff_add(x)
(y + 3, (x,))
>>> (3 + y).as_coeff_add(x)
(y + 3, ())
"""
if deps:
if not self.has(*deps):
return self, tuple()
return S.Zero, (self,)
def primitive(self):
"""Return the positive Rational that can be extracted non-recursively
from every term of self (i.e., self is treated like an Add). This is
like the as_coeff_Mul() method but primitive always extracts a positive
Rational (never a negative or a Float).
Examples
========
>>> from sympy.abc import x
>>> (3*(x + 1)**2).primitive()
(3, (x + 1)**2)
>>> a = (6*x + 2); a.primitive()
(2, 3*x + 1)
>>> b = (x/2 + 3); b.primitive()
(1/2, x + 6)
>>> (a*b).primitive() == (1, a*b)
True
"""
if not self:
return S.One, S.Zero
c, r = self.as_coeff_Mul(rational=True)
if c.is_negative:
c, r = -c, -r
return c, r
def as_content_primitive(self, radical=False, clear=True):
"""This method should recursively remove a Rational from all arguments
and return that (content) and the new self (primitive). The content
should always be positive and ``Mul(*foo.as_content_primitive()) == foo``.
The primitive need not be in canonical form and should try to preserve
the underlying structure if possible (i.e. expand_mul should not be
applied to self).
Examples
========
>>> from sympy import sqrt
>>> from sympy.abc import x, y, z
>>> eq = 2 + 2*x + 2*y*(3 + 3*y)
The as_content_primitive function is recursive and retains structure:
>>> eq.as_content_primitive()
(2, x + 3*y*(y + 1) + 1)
Integer powers will have Rationals extracted from the base:
>>> ((2 + 6*x)**2).as_content_primitive()
(4, (3*x + 1)**2)
>>> ((2 + 6*x)**(2*y)).as_content_primitive()
(1, (2*(3*x + 1))**(2*y))
Terms may end up joining once their as_content_primitives are added:
>>> ((5*(x*(1 + y)) + 2*x*(3 + 3*y))).as_content_primitive()
(11, x*(y + 1))
>>> ((3*(x*(1 + y)) + 2*x*(3 + 3*y))).as_content_primitive()
(9, x*(y + 1))
>>> ((3*(z*(1 + y)) + 2.0*x*(3 + 3*y))).as_content_primitive()
(1, 6.0*x*(y + 1) + 3*z*(y + 1))
>>> ((5*(x*(1 + y)) + 2*x*(3 + 3*y))**2).as_content_primitive()
(121, x**2*(y + 1)**2)
>>> ((5*(x*(1 + y)) + 2.0*x*(3 + 3*y))**2).as_content_primitive()
(1, 121.0*x**2*(y + 1)**2)
Radical content can also be factored out of the primitive:
>>> (2*sqrt(2) + 4*sqrt(10)).as_content_primitive(radical=True)
(2, sqrt(2)*(1 + 2*sqrt(5)))
If clear=False (default is True) then content will not be removed
from an Add if it can be distributed to leave one or more
terms with integer coefficients.
>>> (x/2 + y).as_content_primitive()
(1/2, x + 2*y)
>>> (x/2 + y).as_content_primitive(clear=False)
(1, x/2 + y)
"""
return S.One, self
def as_numer_denom(self):
""" expression -> a/b -> a, b
This is just a stub that should be defined by
an object's class methods to get anything else.
See Also
========
normal: return a/b instead of a, b
"""
return self, S.One
def normal(self):
from .mul import _unevaluated_Mul
n, d = self.as_numer_denom()
if d is S.One:
return n
if d.is_Number:
if d is S.One:
return n
else:
return _unevaluated_Mul(n, 1/d)
else:
return n/d
def extract_multiplicatively(self, c):
"""Return None if it's not possible to make self in the form
c * something in a nice way, i.e. preserving the properties
of arguments of self.
>>> from sympy import symbols, Rational
>>> x, y = symbols('x,y', real=True)
>>> ((x*y)**3).extract_multiplicatively(x**2 * y)
x*y**2
>>> ((x*y)**3).extract_multiplicatively(x**4 * y)
>>> (2*x).extract_multiplicatively(2)
x
>>> (2*x).extract_multiplicatively(3)
>>> (Rational(1, 2)*x).extract_multiplicatively(3)
x/6
"""
from .function import _coeff_isneg
c = sympify(c)
if self is S.NaN:
return None
if c is S.One:
return self
elif c == self:
return S.One
if c.is_Add:
cc, pc = c.primitive()
if cc is not S.One:
c = Mul(cc, pc, evaluate=False)
if c.is_Mul:
a, b = c.as_two_terms()
x = self.extract_multiplicatively(a)
if x is not None:
return x.extract_multiplicatively(b)
quotient = self / c
if self.is_Number:
if self is S.Infinity:
if c.is_positive:
return S.Infinity
elif self is S.NegativeInfinity:
if c.is_negative:
return S.Infinity
elif c.is_positive:
return S.NegativeInfinity
elif self is S.ComplexInfinity:
if not c.is_zero:
return S.ComplexInfinity
elif self.is_Integer:
if not quotient.is_Integer:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_Rational:
if not quotient.is_Rational:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_Float:
if not quotient.is_Float:
return None
elif self.is_positive and quotient.is_negative:
return None
else:
return quotient
elif self.is_NumberSymbol or self.is_Symbol or self is S.ImaginaryUnit:
if quotient.is_Mul and len(quotient.args) == 2:
if quotient.args[0].is_Integer and quotient.args[0].is_positive and quotient.args[1] == self:
return quotient
elif quotient.is_Integer and c.is_Number:
return quotient
elif self.is_Add:
cs, ps = self.primitive()
# assert cs >= 1
if c.is_Number and c is not S.NegativeOne:
# assert c != 1 (handled at top)
if cs is not S.One:
if c.is_negative:
xc = -(cs.extract_multiplicatively(-c))
else:
xc = cs.extract_multiplicatively(c)
if xc is not None:
return xc*ps # rely on 2-arg Mul to restore Add
return # |c| != 1 can only be extracted from cs
if c == ps:
return cs
# check args of ps
newargs = []
for arg in ps.args:
newarg = arg.extract_multiplicatively(c)
if newarg is None:
return # all or nothing
newargs.append(newarg)
# args should be in same order so use unevaluated return
if cs is not S.One:
return Add._from_args([cs*t for t in newargs])
else:
return Add._from_args(newargs)
elif self.is_Mul:
args = list(self.args)
for i, arg in enumerate(args):
newarg = arg.extract_multiplicatively(c)
if newarg is not None:
args[i] = newarg
return Mul(*args)
elif self.is_Pow:
if c.is_Pow and c.base == self.base:
new_exp = self.exp.extract_additively(c.exp)
if new_exp is not None:
return self.base ** (new_exp)
elif c == self.base:
new_exp = self.exp.extract_additively(1)
if new_exp is not None:
return self.base ** (new_exp)
def extract_additively(self, c):
"""Return self - c if it's possible to subtract c from self and
make all matching coefficients move towards zero, else return None.
Examples
========
>>> from sympy.abc import x, y
>>> e = 2*x + 3
>>> e.extract_additively(x + 1)
x + 2
>>> e.extract_additively(3*x)
>>> e.extract_additively(4)
>>> (y*(x + 1)).extract_additively(x + 1)
>>> ((x + 1)*(x + 2*y + 1) + 3).extract_additively(x + 1)
(x + 1)*(x + 2*y) + 3
Sometimes auto-expansion will return a less simplified result
than desired; gcd_terms might be used in such cases:
>>> from sympy import gcd_terms
>>> (4*x*(y + 1) + y).extract_additively(x)
4*x*(y + 1) + x*(4*y + 3) - x*(4*y + 4) + y
>>> gcd_terms(_)
x*(4*y + 3) + y
See Also
========
extract_multiplicatively
coeff
as_coefficient
"""
c = sympify(c)
if self is S.NaN:
return None
if c is S.Zero:
return self
elif c == self:
return S.Zero
elif self is S.Zero:
return None
if self.is_Number:
if not c.is_Number:
return None
co = self
diff = co - c
# XXX should we match types? i.e should 3 - .1 succeed?
if (co > 0 and diff > 0 and diff < co or
co < 0 and diff < 0 and diff > co):
return diff
return None
if c.is_Number:
co, t = self.as_coeff_Add()
xa = co.extract_additively(c)
if xa is None:
return None
return xa + t
# handle the args[0].is_Number case separately
# since we will have trouble looking for the coeff of
# a number.
if c.is_Add and c.args[0].is_Number:
# whole term as a term factor
co = self.coeff(c)
xa0 = (co.extract_additively(1) or 0)*c
if xa0:
diff = self - co*c
return (xa0 + (diff.extract_additively(c) or diff)) or None
# term-wise
h, t = c.as_coeff_Add()
sh, st = self.as_coeff_Add()
xa = sh.extract_additively(h)
if xa is None:
return None
xa2 = st.extract_additively(t)
if xa2 is None:
return None
return xa + xa2
# whole term as a term factor
co = self.coeff(c)
xa0 = (co.extract_additively(1) or 0)*c
if xa0:
diff = self - co*c
return (xa0 + (diff.extract_additively(c) or diff)) or None
# term-wise
coeffs = []
for a in Add.make_args(c):
ac, at = a.as_coeff_Mul()
co = self.coeff(at)
if not co:
return None
coc, cot = co.as_coeff_Add()
xa = coc.extract_additively(ac)
if xa is None:
return None
self -= co*at
coeffs.append((cot + xa)*at)
coeffs.append(self)
return Add(*coeffs)
@property
def expr_free_symbols(self):
"""
Like ``free_symbols``, but returns the free symbols only if they are contained in an expression node.
Examples
========
>>> from sympy.abc import x, y
>>> (x + y).expr_free_symbols
{x, y}
If the expression is contained in a non-expression object, don't return
the free symbols. Compare:
>>> from sympy import Tuple
>>> t = Tuple(x + y)
>>> t.expr_free_symbols
set()
>>> t.free_symbols
{x, y}
"""
return {j for i in self.args for j in i.expr_free_symbols}
def could_extract_minus_sign(self):
"""Return True if self is not in a canonical form with respect
to its sign.
For most expressions, e, there will be a difference in e and -e.
When there is, True will be returned for one and False for the
other; False will be returned if there is no difference.
Examples
========
>>> from sympy.abc import x, y
>>> e = x - y
>>> {i.could_extract_minus_sign() for i in (e, -e)}
{False, True}
"""
negative_self = -self
if self == negative_self:
return False # e.g. zoo*x == -zoo*x
self_has_minus = (self.extract_multiplicatively(-1) is not None)
negative_self_has_minus = (
(negative_self).extract_multiplicatively(-1) is not None)
if self_has_minus != negative_self_has_minus:
return self_has_minus
else:
if self.is_Add:
# We choose the one with less arguments with minus signs
all_args = len(self.args)
negative_args = len([False for arg in self.args if arg.could_extract_minus_sign()])
positive_args = all_args - negative_args
if positive_args > negative_args:
return False
elif positive_args < negative_args:
return True
elif self.is_Mul:
# We choose the one with an odd number of minus signs
num, den = self.as_numer_denom()
args = Mul.make_args(num) + Mul.make_args(den)
arg_signs = [arg.could_extract_minus_sign() for arg in args]
negative_args = list(filter(None, arg_signs))
return len(negative_args) % 2 == 1
# As a last resort, we choose the one with greater value of .sort_key()
return bool(self.sort_key() < negative_self.sort_key())
def extract_branch_factor(self, allow_half=False):
"""
Try to write self as ``exp_polar(2*pi*I*n)*z`` in a nice way.
Return (z, n).
>>> from sympy import exp_polar, I, pi
>>> from sympy.abc import x, y
>>> exp_polar(I*pi).extract_branch_factor()
(exp_polar(I*pi), 0)
>>> exp_polar(2*I*pi).extract_branch_factor()
(1, 1)
>>> exp_polar(-pi*I).extract_branch_factor()
(exp_polar(I*pi), -1)
>>> exp_polar(3*pi*I + x).extract_branch_factor()
(exp_polar(x + I*pi), 1)
>>> (y*exp_polar(-5*pi*I)*exp_polar(3*pi*I + 2*pi*x)).extract_branch_factor()
(y*exp_polar(2*pi*x), -1)
>>> exp_polar(-I*pi/2).extract_branch_factor()
(exp_polar(-I*pi/2), 0)
If allow_half is True, also extract exp_polar(I*pi):
>>> exp_polar(I*pi).extract_branch_factor(allow_half=True)
(1, 1/2)
>>> exp_polar(2*I*pi).extract_branch_factor(allow_half=True)
(1, 1)
>>> exp_polar(3*I*pi).extract_branch_factor(allow_half=True)
(1, 3/2)
>>> exp_polar(-I*pi).extract_branch_factor(allow_half=True)
(1, -1/2)
"""
from sympy import exp_polar, pi, I, ceiling, Add
n = S(0)
res = S(1)
args = Mul.make_args(self)
exps = []
for arg in args:
if isinstance(arg, exp_polar):
exps += [arg.exp]
else:
res *= arg
piimult = S(0)
extras = []
while exps:
exp = exps.pop()
if exp.is_Add:
exps += exp.args
continue
if exp.is_Mul:
coeff = exp.as_coefficient(pi*I)
if coeff is not None:
piimult += coeff
continue
extras += [exp]
if not piimult.free_symbols:
coeff = piimult
tail = ()
else:
coeff, tail = piimult.as_coeff_add(*piimult.free_symbols)
# round down to nearest multiple of 2
branchfact = ceiling(coeff/2 - S(1)/2)*2
n += branchfact/2
c = coeff - branchfact
if allow_half:
nc = c.extract_additively(1)
if nc is not None:
n += S(1)/2
c = nc
newexp = pi*I*Add(*((c, ) + tail)) + Add(*extras)
if newexp != 0:
res *= exp_polar(newexp)
return res, n
def _eval_is_polynomial(self, syms):
if self.free_symbols.intersection(syms) == set([]):
return True
return False
def is_polynomial(self, *syms):
r"""
Return True if self is a polynomial in syms and False otherwise.
This checks if self is an exact polynomial in syms. This function
returns False for expressions that are "polynomials" with symbolic
exponents. Thus, you should be able to apply polynomial algorithms to
expressions for which this returns True, and Poly(expr, \*syms) should
work if and only if expr.is_polynomial(\*syms) returns True. The
polynomial does not have to be in expanded form. If no symbols are
given, all free symbols in the expression will be used.
This is not part of the assumptions system. You cannot do
Symbol('z', polynomial=True).
Examples
========
>>> from sympy import Symbol
>>> x = Symbol('x')
>>> ((x**2 + 1)**4).is_polynomial(x)
True
>>> ((x**2 + 1)**4).is_polynomial()
True
>>> (2**x + 1).is_polynomial(x)
False
>>> n = Symbol('n', nonnegative=True, integer=True)
>>> (x**n + 1).is_polynomial(x)
False
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be a polynomial to
become one.
>>> from sympy import sqrt, factor, cancel
>>> y = Symbol('y', positive=True)
>>> a = sqrt(y**2 + 2*y + 1)
>>> a.is_polynomial(y)
False
>>> factor(a)
y + 1
>>> factor(a).is_polynomial(y)
True
>>> b = (y**2 + 2*y + 1)/(y + 1)
>>> b.is_polynomial(y)
False
>>> cancel(b)
y + 1
>>> cancel(b).is_polynomial(y)
True
See also .is_rational_function()
"""
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if syms.intersection(self.free_symbols) == set([]):
# constant polynomial
return True
else:
return self._eval_is_polynomial(syms)
def _eval_is_rational_function(self, syms):
if self.free_symbols.intersection(syms) == set([]):
return True
return False
def is_rational_function(self, *syms):
"""
Test whether function is a ratio of two polynomials in the given
symbols, syms. When syms is not given, all free symbols will be used.
The rational function does not have to be in expanded or in any kind of
canonical form.
This function returns False for expressions that are "rational
functions" with symbolic exponents. Thus, you should be able to call
.as_numer_denom() and apply polynomial algorithms to the result for
expressions for which this returns True.
This is not part of the assumptions system. You cannot do
Symbol('z', rational_function=True).
Examples
========
>>> from sympy import Symbol, sin
>>> from sympy.abc import x, y
>>> (x/y).is_rational_function()
True
>>> (x**2).is_rational_function()
True
>>> (x/sin(y)).is_rational_function(y)
False
>>> n = Symbol('n', integer=True)
>>> (x**n + 1).is_rational_function(x)
False
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be a rational function
to become one.
>>> from sympy import sqrt, factor
>>> y = Symbol('y', positive=True)
>>> a = sqrt(y**2 + 2*y + 1)/y
>>> a.is_rational_function(y)
False
>>> factor(a)
(y + 1)/y
>>> factor(a).is_rational_function(y)
True
See also is_algebraic_expr().
"""
if self in [S.NaN, S.Infinity, -S.Infinity, S.ComplexInfinity]:
return False
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if syms.intersection(self.free_symbols) == set([]):
# constant rational function
return True
else:
return self._eval_is_rational_function(syms)
def _eval_is_algebraic_expr(self, syms):
if self.free_symbols.intersection(syms) == set([]):
return True
return False
def is_algebraic_expr(self, *syms):
"""
This tests whether a given expression is algebraic or not, in the
given symbols, syms. When syms is not given, all free symbols
will be used. The rational function does not have to be in expanded
or in any kind of canonical form.
This function returns False for expressions that are "algebraic
expressions" with symbolic exponents. This is a simple extension to the
is_rational_function, including rational exponentiation.
Examples
========
>>> from sympy import Symbol, sqrt
>>> x = Symbol('x', real=True)
>>> sqrt(1 + x).is_rational_function()
False
>>> sqrt(1 + x).is_algebraic_expr()
True
This function does not attempt any nontrivial simplifications that may
result in an expression that does not appear to be an algebraic
expression to become one.
>>> from sympy import exp, factor
>>> a = sqrt(exp(x)**2 + 2*exp(x) + 1)/(exp(x) + 1)
>>> a.is_algebraic_expr(x)
False
>>> factor(a).is_algebraic_expr()
True
See Also
========
is_rational_function()
References
==========
- https://en.wikipedia.org/wiki/Algebraic_expression
"""
if syms:
syms = set(map(sympify, syms))
else:
syms = self.free_symbols
if syms.intersection(self.free_symbols) == set([]):
# constant algebraic expression
return True
else:
return self._eval_is_algebraic_expr(syms)
###################################################################################
##################### SERIES, LEADING TERM, LIMIT, ORDER METHODS ##################
###################################################################################
def series(self, x=None, x0=0, n=6, dir="+", logx=None):
"""
Series expansion of "self" around ``x = x0`` yielding either terms of
the series one by one (the lazy series given when n=None), else
all the terms at once when n != None.
Returns the series expansion of "self" around the point ``x = x0``
with respect to ``x`` up to ``O((x - x0)**n, x, x0)`` (default n is 6).
If ``x=None`` and ``self`` is univariate, the univariate symbol will
be supplied, otherwise an error will be raised.
>>> from sympy import cos, exp
>>> from sympy.abc import x, y
>>> cos(x).series()
1 - x**2/2 + x**4/24 + O(x**6)
>>> cos(x).series(n=4)
1 - x**2/2 + O(x**4)
>>> cos(x).series(x, x0=1, n=2)
cos(1) - (x - 1)*sin(1) + O((x - 1)**2, (x, 1))
>>> e = cos(x + exp(y))
>>> e.series(y, n=2)
cos(x + 1) - y*sin(x + 1) + O(y**2)
>>> e.series(x, n=2)
cos(exp(y)) - x*sin(exp(y)) + O(x**2)
If ``n=None`` then a generator of the series terms will be returned.
>>> term=cos(x).series(n=None)
>>> [next(term) for i in range(2)]
[1, -x**2/2]
For ``dir=+`` (default) the series is calculated from the right and
for ``dir=-`` the series from the left. For smooth functions this
flag will not alter the results.
>>> abs(x).series(dir="+")
x
>>> abs(x).series(dir="-")
-x
"""
from sympy import collect, Dummy, Order, Rational, Symbol, ceiling
if x is None:
syms = self.free_symbols
if not syms:
return self
elif len(syms) > 1:
raise ValueError('x must be given for multivariate functions.')
x = syms.pop()
if isinstance(x, Symbol):
dep = x in self.free_symbols
else:
d = Dummy()
dep = d in self.xreplace({x: d}).free_symbols
if not dep:
if n is None:
return (s for s in [self])
else:
return self
if len(dir) != 1 or dir not in '+-':
raise ValueError("Dir must be '+' or '-'")
if x0 in [S.Infinity, S.NegativeInfinity]:
sgn = 1 if x0 is S.Infinity else -1
s = self.subs(x, sgn/x).series(x, n=n, dir='+')
if n is None:
return (si.subs(x, sgn/x) for si in s)
return s.subs(x, sgn/x)
# use rep to shift origin to x0 and change sign (if dir is negative)
# and undo the process with rep2
if x0 or dir == '-':
if dir == '-':
rep = -x + x0
rep2 = -x
rep2b = x0
else:
rep = x + x0
rep2 = x
rep2b = -x0
s = self.subs(x, rep).series(x, x0=0, n=n, dir='+', logx=logx)
if n is None: # lseries...
return (si.subs(x, rep2 + rep2b) for si in s)
return s.subs(x, rep2 + rep2b)
# from here on it's x0=0 and dir='+' handling
if x.is_positive is x.is_negative is None or x.is_Symbol is not True:
# replace x with an x that has a positive assumption
xpos = Dummy('x', positive=True, finite=True)
rv = self.subs(x, xpos).series(xpos, x0, n, dir, logx=logx)
if n is None:
return (s.subs(xpos, x) for s in rv)
else:
return rv.subs(xpos, x)
if n is not None: # nseries handling
s1 = self._eval_nseries(x, n=n, logx=logx)
o = s1.getO() or S.Zero
if o:
# make sure the requested order is returned
ngot = o.getn()
if ngot > n:
# leave o in its current form (e.g. with x*log(x)) so
# it eats terms properly, then replace it below
if n != 0:
s1 += o.subs(x, x**Rational(n, ngot))
else:
s1 += Order(1, x)
elif ngot < n:
# increase the requested number of terms to get the desired
# number keep increasing (up to 9) until the received order
# is different than the original order and then predict how
# many additional terms are needed
for more in range(1, 9):
s1 = self._eval_nseries(x, n=n + more, logx=logx)
newn = s1.getn()
if newn != ngot:
ndo = n + ceiling((n - ngot)*more/(newn - ngot))
s1 = self._eval_nseries(x, n=ndo, logx=logx)
while s1.getn() < n:
s1 = self._eval_nseries(x, n=ndo, logx=logx)
ndo += 1
break
else:
raise ValueError('Could not calculate %s terms for %s'
% (str(n), self))
s1 += Order(x**n, x)
o = s1.getO()
s1 = s1.removeO()
else:
o = Order(x**n, x)
s1done = s1.doit()
if (s1done + o).removeO() == s1done:
o = S.Zero
try:
return collect(s1, x) + o
except NotImplementedError:
return s1 + o
else: # lseries handling
def yield_lseries(s):
"""Return terms of lseries one at a time."""
for si in s:
if not si.is_Add:
yield si
continue
# yield terms 1 at a time if possible
# by increasing order until all the
# terms have been returned
yielded = 0
o = Order(si, x)*x
ndid = 0
ndo = len(si.args)
while 1:
do = (si - yielded + o).removeO()
o *= x
if not do or do.is_Order:
continue
if do.is_Add:
ndid += len(do.args)
else:
ndid += 1
yield do
if ndid == ndo:
break
yielded += do
return yield_lseries(self.removeO()._eval_lseries(x, logx=logx))
def taylor_term(self, n, x, *previous_terms):
"""General method for the taylor term.
This method is slow, because it differentiates n-times. Subclasses can
redefine it to make it faster by using the "previous_terms".
"""
from sympy import Dummy, factorial
x = sympify(x)
_x = Dummy('x')
return self.subs(x, _x).diff(_x, n).subs(_x, x).subs(x, 0) * x**n / factorial(n)
def lseries(self, x=None, x0=0, dir='+', logx=None):
"""
Wrapper for series yielding an iterator of the terms of the series.
Note: an infinite series will yield an infinite iterator. The following,
for exaxmple, will never terminate. It will just keep printing terms
of the sin(x) series::
for term in sin(x).lseries(x):
print term
The advantage of lseries() over nseries() is that many times you are
just interested in the next term in the series (i.e. the first term for
example), but you don't know how many you should ask for in nseries()
using the "n" parameter.
See also nseries().
"""
return self.series(x, x0, n=None, dir=dir, logx=logx)
def _eval_lseries(self, x, logx=None):
# default implementation of lseries is using nseries(), and adaptively
# increasing the "n". As you can see, it is not very efficient, because
# we are calculating the series over and over again. Subclasses should
# override this method and implement much more efficient yielding of
# terms.
n = 0
series = self._eval_nseries(x, n=n, logx=logx)
if not series.is_Order:
if series.is_Add:
yield series.removeO()
else:
yield series
return
while series.is_Order:
n += 1
series = self._eval_nseries(x, n=n, logx=logx)
e = series.removeO()
yield e
while 1:
while 1:
n += 1
series = self._eval_nseries(x, n=n, logx=logx).removeO()
if e != series:
break
yield series - e
e = series
def nseries(self, x=None, x0=0, n=6, dir='+', logx=None):
"""
Wrapper to _eval_nseries if assumptions allow, else to series.
If x is given, x0 is 0, dir='+', and self has x, then _eval_nseries is
called. This calculates "n" terms in the innermost expressions and
then builds up the final series just by "cross-multiplying" everything
out.
The optional ``logx`` parameter can be used to replace any log(x) in the
returned series with a symbolic value to avoid evaluating log(x) at 0. A
symbol to use in place of log(x) should be provided.
Advantage -- it's fast, because we don't have to determine how many
terms we need to calculate in advance.
Disadvantage -- you may end up with less terms than you may have
expected, but the O(x**n) term appended will always be correct and
so the result, though perhaps shorter, will also be correct.
If any of those assumptions is not met, this is treated like a
wrapper to series which will try harder to return the correct
number of terms.
See also lseries().
Examples
========
>>> from sympy import sin, log, Symbol
>>> from sympy.abc import x, y
>>> sin(x).nseries(x, 0, 6)
x - x**3/6 + x**5/120 + O(x**6)
>>> log(x+1).nseries(x, 0, 5)
x - x**2/2 + x**3/3 - x**4/4 + O(x**5)
Handling of the ``logx`` parameter --- in the following example the
expansion fails since ``sin`` does not have an asymptotic expansion
at -oo (the limit of log(x) as x approaches 0):
>>> e = sin(log(x))
>>> e.nseries(x, 0, 6)
Traceback (most recent call last):
...
PoleError: ...
...
>>> logx = Symbol('logx')
>>> e.nseries(x, 0, 6, logx=logx)
sin(logx)
In the following example, the expansion works but gives only an Order term
unless the ``logx`` parameter is used:
>>> e = x**y
>>> e.nseries(x, 0, 2)
O(log(x)**2)
>>> e.nseries(x, 0, 2, logx=logx)
exp(logx*y)
"""
if x and not x in self.free_symbols:
return self
if x is None or x0 or dir != '+': # {see XPOS above} or (x.is_positive == x.is_negative == None):
return self.series(x, x0, n, dir)
else:
return self._eval_nseries(x, n=n, logx=logx)
def _eval_nseries(self, x, n, logx):
"""
Return terms of series for self up to O(x**n) at x=0
from the positive direction.
This is a method that should be overridden in subclasses. Users should
never call this method directly (use .nseries() instead), so you don't
have to write docstrings for _eval_nseries().
"""
from sympy.utilities.misc import filldedent
raise NotImplementedError(filldedent("""
The _eval_nseries method should be added to
%s to give terms up to O(x**n) at x=0
from the positive direction so it is available when
nseries calls it.""" % self.func)
)
def limit(self, x, xlim, dir='+'):
""" Compute limit x->xlim.
"""
from sympy.series.limits import limit
return limit(self, x, xlim, dir)
def compute_leading_term(self, x, logx=None):
"""
as_leading_term is only allowed for results of .series()
This is a wrapper to compute a series first.
"""
from sympy import Dummy, log
from sympy.series.gruntz import calculate_series
if self.removeO() == 0:
return self
if logx is None:
d = Dummy('logx')
s = calculate_series(self, x, d).subs(d, log(x))
else:
s = calculate_series(self, x, logx)
return s.as_leading_term(x)
@cacheit
def as_leading_term(self, *symbols):
"""
Returns the leading (nonzero) term of the series expansion of self.
The _eval_as_leading_term routines are used to do this, and they must
always return a non-zero value.
Examples
========
>>> from sympy.abc import x
>>> (1 + x + x**2).as_leading_term(x)
1
>>> (1/x**2 + x + x**2).as_leading_term(x)
x**(-2)
"""
from sympy import powsimp
if len(symbols) > 1:
c = self
for x in symbols:
c = c.as_leading_term(x)
return c
elif not symbols:
return self
x = sympify(symbols[0])
if not x.is_symbol:
raise ValueError('expecting a Symbol but got %s' % x)
if x not in self.free_symbols:
return self
obj = self._eval_as_leading_term(x)
if obj is not None:
return powsimp(obj, deep=True, combine='exp')
raise NotImplementedError('as_leading_term(%s, %s)' % (self, x))
def _eval_as_leading_term(self, x):
return self
def as_coeff_exponent(self, x):
""" ``c*x**e -> c,e`` where x can be any symbolic expression.
"""
from sympy import collect
s = collect(self, x)
c, p = s.as_coeff_mul(x)
if len(p) == 1:
b, e = p[0].as_base_exp()
if b == x:
return c, e
return s, S.Zero
def leadterm(self, x):
"""
Returns the leading term a*x**b as a tuple (a, b).
Examples
========
>>> from sympy.abc import x
>>> (1+x+x**2).leadterm(x)
(1, 0)
>>> (1/x**2+x+x**2).leadterm(x)
(1, -2)
"""
from sympy import Dummy, log
l = self.as_leading_term(x)
d = Dummy('logx')
if l.has(log(x)):
l = l.subs(log(x), d)
c, e = l.as_coeff_exponent(x)
if x in c.free_symbols:
from sympy.utilities.misc import filldedent
raise ValueError(filldedent("""
cannot compute leadterm(%s, %s). The coefficient
should have been free of x but got %s""" % (self, x, c)))
c = c.subs(d, log(x))
return c, e
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product. """
return S.One, self
def as_coeff_Add(self, rational=False):
"""Efficiently extract the coefficient of a summation. """
return S.Zero, self
def fps(self, x=None, x0=0, dir=1, hyper=True, order=4, rational=True,
full=False):
"""
Compute formal power power series of self.
See the docstring of the :func:`fps` function in sympy.series.formal for
more information.
"""
from sympy.series.formal import fps
return fps(self, x, x0, dir, hyper, order, rational, full)
def fourier_series(self, limits=None):
"""Compute fourier sine/cosine series of self.
See the docstring of the :func:`fourier_series` in sympy.series.fourier
for more information.
"""
from sympy.series.fourier import fourier_series
return fourier_series(self, limits)
###################################################################################
##################### DERIVATIVE, INTEGRAL, FUNCTIONAL METHODS ####################
###################################################################################
def diff(self, *symbols, **assumptions):
assumptions.setdefault("evaluate", True)
return Derivative(self, *symbols, **assumptions)
###########################################################################
###################### EXPRESSION EXPANSION METHODS #######################
###########################################################################
# Relevant subclasses should override _eval_expand_hint() methods. See
# the docstring of expand() for more info.
def _eval_expand_complex(self, **hints):
real, imag = self.as_real_imag(**hints)
return real + S.ImaginaryUnit*imag
@staticmethod
def _expand_hint(expr, hint, deep=True, **hints):
"""
Helper for ``expand()``. Recursively calls ``expr._eval_expand_hint()``.
Returns ``(expr, hit)``, where expr is the (possibly) expanded
``expr`` and ``hit`` is ``True`` if ``expr`` was truly expanded and
``False`` otherwise.
"""
hit = False
# XXX: Hack to support non-Basic args
# |
# V
if deep and getattr(expr, 'args', ()) and not expr.is_Atom:
sargs = []
for arg in expr.args:
arg, arghit = Expr._expand_hint(arg, hint, **hints)
hit |= arghit
sargs.append(arg)
if hit:
expr = expr.func(*sargs)
if hasattr(expr, hint):
newexpr = getattr(expr, hint)(**hints)
if newexpr != expr:
return (newexpr, True)
return (expr, hit)
@cacheit
def expand(self, deep=True, modulus=None, power_base=True, power_exp=True,
mul=True, log=True, multinomial=True, basic=True, **hints):
"""
Expand an expression using hints.
See the docstring of the expand() function in sympy.core.function for
more information.
"""
from sympy.simplify.radsimp import fraction
hints.update(power_base=power_base, power_exp=power_exp, mul=mul,
log=log, multinomial=multinomial, basic=basic)
expr = self
if hints.pop('frac', False):
n, d = [a.expand(deep=deep, modulus=modulus, **hints)
for a in fraction(self)]
return n/d
elif hints.pop('denom', False):
n, d = fraction(self)
return n/d.expand(deep=deep, modulus=modulus, **hints)
elif hints.pop('numer', False):
n, d = fraction(self)
return n.expand(deep=deep, modulus=modulus, **hints)/d
# Although the hints are sorted here, an earlier hint may get applied
# at a given node in the expression tree before another because of how
# the hints are applied. e.g. expand(log(x*(y + z))) -> log(x*y +
# x*z) because while applying log at the top level, log and mul are
# applied at the deeper level in the tree so that when the log at the
# upper level gets applied, the mul has already been applied at the
# lower level.
# Additionally, because hints are only applied once, the expression
# may not be expanded all the way. For example, if mul is applied
# before multinomial, x*(x + 1)**2 won't be expanded all the way. For
# now, we just use a special case to make multinomial run before mul,
# so that at least polynomials will be expanded all the way. In the
# future, smarter heuristics should be applied.
# TODO: Smarter heuristics
def _expand_hint_key(hint):
"""Make multinomial come before mul"""
if hint == 'mul':
return 'mulz'
return hint
for hint in sorted(hints.keys(), key=_expand_hint_key):
use_hint = hints[hint]
if use_hint:
hint = '_eval_expand_' + hint
expr, hit = Expr._expand_hint(expr, hint, deep=deep, **hints)
while True:
was = expr
if hints.get('multinomial', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_multinomial', deep=deep, **hints)
if hints.get('mul', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_mul', deep=deep, **hints)
if hints.get('log', False):
expr, _ = Expr._expand_hint(
expr, '_eval_expand_log', deep=deep, **hints)
if expr == was:
break
if modulus is not None:
modulus = sympify(modulus)
if not modulus.is_Integer or modulus <= 0:
raise ValueError(
"modulus must be a positive integer, got %s" % modulus)
terms = []
for term in Add.make_args(expr):
coeff, tail = term.as_coeff_Mul(rational=True)
coeff %= modulus
if coeff:
terms.append(coeff*tail)
expr = Add(*terms)
return expr
###########################################################################
################### GLOBAL ACTION VERB WRAPPER METHODS ####################
###########################################################################
def integrate(self, *args, **kwargs):
"""See the integrate function in sympy.integrals"""
from sympy.integrals import integrate
return integrate(self, *args, **kwargs)
def simplify(self, ratio=1.7, measure=None, rational=False, inverse=False):
"""See the simplify function in sympy.simplify"""
from sympy.simplify import simplify
from sympy.core.function import count_ops
measure = measure or count_ops
return simplify(self, ratio, measure)
def nsimplify(self, constants=[], tolerance=None, full=False):
"""See the nsimplify function in sympy.simplify"""
from sympy.simplify import nsimplify
return nsimplify(self, constants, tolerance, full)
def separate(self, deep=False, force=False):
"""See the separate function in sympy.simplify"""
from sympy.core.function import expand_power_base
return expand_power_base(self, deep=deep, force=force)
def collect(self, syms, func=None, evaluate=True, exact=False, distribute_order_term=True):
"""See the collect function in sympy.simplify"""
from sympy.simplify import collect
return collect(self, syms, func, evaluate, exact, distribute_order_term)
def together(self, *args, **kwargs):
"""See the together function in sympy.polys"""
from sympy.polys import together
return together(self, *args, **kwargs)
def apart(self, x=None, **args):
"""See the apart function in sympy.polys"""
from sympy.polys import apart
return apart(self, x, **args)
def ratsimp(self):
"""See the ratsimp function in sympy.simplify"""
from sympy.simplify import ratsimp
return ratsimp(self)
def trigsimp(self, **args):
"""See the trigsimp function in sympy.simplify"""
from sympy.simplify import trigsimp
return trigsimp(self, **args)
def radsimp(self, **kwargs):
"""See the radsimp function in sympy.simplify"""
from sympy.simplify import radsimp
return radsimp(self, **kwargs)
def powsimp(self, *args, **kwargs):
"""See the powsimp function in sympy.simplify"""
from sympy.simplify import powsimp
return powsimp(self, *args, **kwargs)
def combsimp(self):
"""See the combsimp function in sympy.simplify"""
from sympy.simplify import combsimp
return combsimp(self)
def gammasimp(self):
"""See the gammasimp function in sympy.simplify"""
from sympy.simplify import gammasimp
return gammasimp(self)
def factor(self, *gens, **args):
"""See the factor() function in sympy.polys.polytools"""
from sympy.polys import factor
return factor(self, *gens, **args)
def refine(self, assumption=True):
"""See the refine function in sympy.assumptions"""
from sympy.assumptions import refine
return refine(self, assumption)
def cancel(self, *gens, **args):
"""See the cancel function in sympy.polys"""
from sympy.polys import cancel
return cancel(self, *gens, **args)
def invert(self, g, *gens, **args):
"""Return the multiplicative inverse of ``self`` mod ``g``
where ``self`` (and ``g``) may be symbolic expressions).
See Also
========
sympy.core.numbers.mod_inverse, sympy.polys.polytools.invert
"""
from sympy.polys.polytools import invert
from sympy.core.numbers import mod_inverse
if self.is_number and getattr(g, 'is_number', True):
return mod_inverse(self, g)
return invert(self, g, *gens, **args)
def round(self, p=0):
"""Return x rounded to the given decimal place.
If a complex number would results, apply round to the real
and imaginary components of the number.
Examples
========
>>> from sympy import pi, E, I, S, Add, Mul, Number
>>> S(10.5).round()
11.
>>> pi.round()
3.
>>> pi.round(2)
3.14
>>> (2*pi + E*I).round()
6. + 3.*I
The round method has a chopping effect:
>>> (2*pi + I/10).round()
6.
>>> (pi/10 + 2*I).round()
2.*I
>>> (pi/10 + E*I).round(2)
0.31 + 2.72*I
Notes
=====
Do not confuse the Python builtin function, round, with the
SymPy method of the same name. The former always returns a float
(or raises an error if applied to a complex value) while the
latter returns either a Number or a complex number:
>>> isinstance(round(S(123), -2), Number)
False
>>> isinstance(S(123).round(-2), Number)
True
>>> isinstance((3*I).round(), Mul)
True
>>> isinstance((1 + 3*I).round(), Add)
True
"""
from sympy import Float
x = self
if not x.is_number:
raise TypeError("can't round symbolic expression")
if not x.is_Atom:
xn = x.n(2)
if not pure_complex(xn, or_real=True):
raise TypeError('Expected a number but got %s:' %
getattr(getattr(x,'func', x), '__name__', type(x)))
elif x in (S.NaN, S.Infinity, S.NegativeInfinity, S.ComplexInfinity):
return x
if not x.is_real:
i, r = x.as_real_imag()
return i.round(p) + S.ImaginaryUnit*r.round(p)
if not x:
return x
p = int(p)
precs = [f._prec for f in x.atoms(Float)]
dps = prec_to_dps(max(precs)) if precs else None
mag_first_dig = _mag(x)
allow = digits_needed = mag_first_dig + p
if dps is not None and allow > dps:
allow = dps
mag = Pow(10, p) # magnitude needed to bring digit p to units place
xwas = x
x += 1/(2*mag) # add the half for rounding
i10 = 10*mag*x.n((dps if dps is not None else digits_needed) + 1)
if i10.is_negative:
x = xwas - 1/(2*mag) # should have gone the other way
i10 = 10*mag*x.n((dps if dps is not None else digits_needed) + 1)
rv = -(Integer(-i10)//10)
else:
rv = Integer(i10)//10
q = 1
if p > 0:
q = mag
elif p < 0:
rv /= mag
rv = Rational(rv, q)
if rv.is_Integer:
# use str or else it won't be a float
return Float(str(rv), digits_needed)
else:
if not allow and rv > self:
allow += 1
return Float(rv, allow)
class AtomicExpr(Atom, Expr):
"""
A parent class for object which are both atoms and Exprs.
For example: Symbol, Number, Rational, Integer, ...
But not: Add, Mul, Pow, ...
"""
is_number = False
is_Atom = True
__slots__ = []
def _eval_derivative(self, s):
if self == s:
return S.One
return S.Zero
def _eval_derivative_n_times(self, s, n):
from sympy import Piecewise, Eq
from sympy import Tuple
from sympy.matrices.common import MatrixCommon
if isinstance(s, (MatrixCommon, Tuple, Iterable)):
return super(AtomicExpr, self)._eval_derivative_n_times(s, n)
if self == s:
return Piecewise((self, Eq(n, 0)), (1, Eq(n, 1)), (0, True))
else:
return Piecewise((self, Eq(n, 0)), (0, True))
def _eval_is_polynomial(self, syms):
return True
def _eval_is_rational_function(self, syms):
return True
def _eval_is_algebraic_expr(self, syms):
return True
def _eval_nseries(self, x, n, logx):
return self
@property
def expr_free_symbols(self):
return {self}
def _mag(x):
"""Return integer ``i`` such that .1 <= x/10**i < 1
Examples
========
>>> from sympy.core.expr import _mag
>>> from sympy import Float
>>> _mag(Float(.1))
0
>>> _mag(Float(.01))
-1
>>> _mag(Float(1234))
4
"""
from math import log10, ceil, log
from sympy import Float
xpos = abs(x.n())
if not xpos:
return S.Zero
try:
mag_first_dig = int(ceil(log10(xpos)))
except (ValueError, OverflowError):
mag_first_dig = int(ceil(Float(mpf_log(xpos._mpf_, 53))/log(10)))
# check that we aren't off by 1
if (xpos/10**mag_first_dig) >= 1:
assert 1 <= (xpos/10**mag_first_dig) < 10
mag_first_dig += 1
return mag_first_dig
class UnevaluatedExpr(Expr):
"""
Expression that is not evaluated unless released.
Examples
========
>>> from sympy import UnevaluatedExpr
>>> from sympy.abc import a, b, x, y
>>> x*(1/x)
1
>>> x*UnevaluatedExpr(1/x)
x*1/x
"""
def __new__(cls, arg, **kwargs):
arg = _sympify(arg)
obj = Expr.__new__(cls, arg, **kwargs)
return obj
def doit(self, **kwargs):
if kwargs.get("deep", True):
return self.args[0].doit(**kwargs)
else:
return self.args[0]
def _n2(a, b):
"""Return (a - b).evalf(2) if a and b are comparable, else None.
This should only be used when a and b are already sympified.
"""
# /!\ it is very important (see issue 8245) not to
# use a re-evaluated number in the calculation of dif
if a.is_comparable and b.is_comparable:
dif = (a - b).evalf(2)
if dif.is_comparable:
return dif
from .mul import Mul
from .add import Add
from .power import Pow
from .function import Derivative, Function
from .mod import Mod
from .exprtools import factor_terms
from .numbers import Integer, Rational
|
bd6a33f5967633dfae273d1fec6da6dc17213d721296b1f21c2a49ac5246f4ed
|
from __future__ import print_function, division
import decimal
import fractions
import math
import re as regex
from collections import defaultdict
from .containers import Tuple
from .sympify import converter, sympify, _sympify, SympifyError, _convert_numpy_types
from .singleton import S, Singleton
from .expr import Expr, AtomicExpr
from .decorators import _sympifyit
from .cache import cacheit, clear_cache
from .logic import fuzzy_not
from sympy.core.compatibility import (
as_int, integer_types, long, string_types, with_metaclass, HAS_GMPY,
SYMPY_INTS, int_info)
from sympy.core.cache import lru_cache
import mpmath
import mpmath.libmp as mlib
from mpmath.libmp.backend import MPZ
from mpmath.libmp import mpf_pow, mpf_pi, mpf_e, phi_fixed
from mpmath.ctx_mp import mpnumeric
from mpmath.libmp.libmpf import (
finf as _mpf_inf, fninf as _mpf_ninf,
fnan as _mpf_nan, fzero as _mpf_zero, _normalize as mpf_normalize,
prec_to_dps)
from sympy.utilities.misc import debug, filldedent
from .evaluate import global_evaluate
from sympy.utilities.exceptions import SymPyDeprecationWarning
rnd = mlib.round_nearest
_LOG2 = math.log(2)
def comp(z1, z2, tol=None):
"""Return a bool indicating whether the error between z1 and z2 is <= tol.
If ``tol`` is None then True will be returned if there is a significant
difference between the numbers: ``abs(z1 - z2)*10**p <= 1/2`` where ``p``
is the lower of the precisions of the values. A comparison of strings will
be made if ``z1`` is a Number and a) ``z2`` is a string or b) ``tol`` is ''
and ``z2`` is a Number.
When ``tol`` is a nonzero value, if z2 is non-zero and ``|z1| > 1``
the error is normalized by ``|z1|``, so if you want to see if the
absolute error between ``z1`` and ``z2`` is <= ``tol`` then call this
as ``comp(z1 - z2, 0, tol)``.
"""
if type(z2) is str:
if not isinstance(z1, Number):
raise ValueError('when z2 is a str z1 must be a Number')
return str(z1) == z2
if not z1:
z1, z2 = z2, z1
if not z1:
return True
if not tol:
if tol is None:
if type(z2) is str and getattr(z1, 'is_Number', False):
return str(z1) == z2
a, b = Float(z1), Float(z2)
return int(abs(a - b)*10**prec_to_dps(
min(a._prec, b._prec)))*2 <= 1
elif all(getattr(i, 'is_Number', False) for i in (z1, z2)):
return z1._prec == z2._prec and str(z1) == str(z2)
raise ValueError('exact comparison requires two Numbers')
diff = abs(z1 - z2)
az1 = abs(z1)
if z2 and az1 > 1:
return diff/az1 <= tol
else:
return diff <= tol
def mpf_norm(mpf, prec):
"""Return the mpf tuple normalized appropriately for the indicated
precision after doing a check to see if zero should be returned or
not when the mantissa is 0. ``mpf_normlize`` always assumes that this
is zero, but it may not be since the mantissa for mpf's values "+inf",
"-inf" and "nan" have a mantissa of zero, too.
Note: this is not intended to validate a given mpf tuple, so sending
mpf tuples that were not created by mpmath may produce bad results. This
is only a wrapper to ``mpf_normalize`` which provides the check for non-
zero mpfs that have a 0 for the mantissa.
"""
sign, man, expt, bc = mpf
if not man:
# hack for mpf_normalize which does not do this;
# it assumes that if man is zero the result is 0
# (see issue 6639)
if not bc:
return _mpf_zero
else:
# don't change anything; this should already
# be a well formed mpf tuple
return mpf
# Necessary if mpmath is using the gmpy backend
from mpmath.libmp.backend import MPZ
rv = mpf_normalize(sign, MPZ(man), expt, bc, prec, rnd)
return rv
# TODO: we should use the warnings module
_errdict = {"divide": False}
def seterr(divide=False):
"""
Should sympy raise an exception on 0/0 or return a nan?
divide == True .... raise an exception
divide == False ... return nan
"""
if _errdict["divide"] != divide:
clear_cache()
_errdict["divide"] = divide
def _as_integer_ratio(p):
neg_pow, man, expt, bc = getattr(p, '_mpf_', mpmath.mpf(p)._mpf_)
p = [1, -1][neg_pow % 2]*man
if expt < 0:
q = 2**-expt
else:
q = 1
p *= 2**expt
return int(p), int(q)
def _decimal_to_Rational_prec(dec):
"""Convert an ordinary decimal instance to a Rational."""
if not dec.is_finite():
raise TypeError("dec must be finite, got %s." % dec)
s, d, e = dec.as_tuple()
prec = len(d)
if e >= 0: # it's an integer
rv = Integer(int(dec))
else:
s = (-1)**s
d = sum([di*10**i for i, di in enumerate(reversed(d))])
rv = Rational(s*d, 10**-e)
return rv, prec
def _literal_float(f):
"""Return True if n can be interpreted as a floating point number."""
pat = r"[-+]?((\d*\.\d+)|(\d+\.?))(eE[-+]?\d+)?"
return bool(regex.match(pat, f))
# (a,b) -> gcd(a,b)
# TODO caching with decorator, but not to degrade performance
@lru_cache(1024)
def igcd(*args):
"""Computes nonnegative integer greatest common divisor.
The algorithm is based on the well known Euclid's algorithm. To
improve speed, igcd() has its own caching mechanism implemented.
Examples
========
>>> from sympy.core.numbers import igcd
>>> igcd(2, 4)
2
>>> igcd(5, 10, 15)
5
"""
if len(args) < 2:
raise TypeError(
'igcd() takes at least 2 arguments (%s given)' % len(args))
if 1 in args:
a = 1
k = 0
else:
a = abs(as_int(args[0]))
k = 1
if a != 1:
while k < len(args):
b = args[k]
k += 1
b = as_int(b)
if not b:
continue
if b == 1:
a = 1
break
if b < 0:
b = -b
a = igcd2(a, b)
while k < len(args):
ok = as_int(args[k])
k += 1
return a
try:
from math import gcd as igcd2
except ImportError:
def igcd2(a, b):
"""Compute gcd of two Python integers a and b."""
if (a.bit_length() > BIGBITS and
b.bit_length() > BIGBITS):
return igcd_lehmer(a, b)
a, b = abs(a), abs(b)
while b:
a, b = b, a % b
return a
# Use Lehmer's algorithm only for very large numbers.
# The limit could be different on Python 2.7 and 3.x.
# If so, then this could be defined in compatibility.py.
BIGBITS = 5000
def igcd_lehmer(a, b):
"""Computes greatest common divisor of two integers.
Euclid's algorithm for the computation of the greatest
common divisor gcd(a, b) of two (positive) integers
a and b is based on the division identity
a = q*b + r,
where the quotient q and the remainder r are integers
and 0 <= r < b. Then each common divisor of a and b
divides r, and it follows that gcd(a, b) == gcd(b, r).
The algorithm works by constructing the sequence
r0, r1, r2, ..., where r0 = a, r1 = b, and each rn
is the remainder from the division of the two preceding
elements.
In Python, q = a // b and r = a % b are obtained by the
floor division and the remainder operations, respectively.
These are the most expensive arithmetic operations, especially
for large a and b.
Lehmer's algorithm is based on the observation that the quotients
qn = r(n-1) // rn are in general small integers even
when a and b are very large. Hence the quotients can be
usually determined from a relatively small number of most
significant bits.
The efficiency of the algorithm is further enhanced by not
computing each long remainder in Euclid's sequence. The remainders
are linear combinations of a and b with integer coefficients
derived from the quotients. The coefficients can be computed
as far as the quotients can be determined from the chosen
most significant parts of a and b. Only then a new pair of
consecutive remainders is computed and the algorithm starts
anew with this pair.
References
==========
.. [1] https://en.wikipedia.org/wiki/Lehmer%27s_GCD_algorithm
"""
a, b = abs(as_int(a)), abs(as_int(b))
if a < b:
a, b = b, a
# The algorithm works by using one or two digit division
# whenever possible. The outer loop will replace the
# pair (a, b) with a pair of shorter consecutive elements
# of the Euclidean gcd sequence until a and b
# fit into two Python (long) int digits.
nbits = 2*int_info.bits_per_digit
while a.bit_length() > nbits and b != 0:
# Quotients are mostly small integers that can
# be determined from most significant bits.
n = a.bit_length() - nbits
x, y = int(a >> n), int(b >> n) # most significant bits
# Elements of the Euclidean gcd sequence are linear
# combinations of a and b with integer coefficients.
# Compute the coefficients of consecutive pairs
# a' = A*a + B*b, b' = C*a + D*b
# using small integer arithmetic as far as possible.
A, B, C, D = 1, 0, 0, 1 # initial values
while True:
# The coefficients alternate in sign while looping.
# The inner loop combines two steps to keep track
# of the signs.
# At this point we have
# A > 0, B <= 0, C <= 0, D > 0,
# x' = x + B <= x < x" = x + A,
# y' = y + C <= y < y" = y + D,
# and
# x'*N <= a' < x"*N, y'*N <= b' < y"*N,
# where N = 2**n.
# Now, if y' > 0, and x"//y' and x'//y" agree,
# then their common value is equal to q = a'//b'.
# In addition,
# x'%y" = x' - q*y" < x" - q*y' = x"%y',
# and
# (x'%y")*N < a'%b' < (x"%y')*N.
# On the other hand, we also have x//y == q,
# and therefore
# x'%y" = x + B - q*(y + D) = x%y + B',
# x"%y' = x + A - q*(y + C) = x%y + A',
# where
# B' = B - q*D < 0, A' = A - q*C > 0.
if y + C <= 0:
break
q = (x + A) // (y + C)
# Now x'//y" <= q, and equality holds if
# x' - q*y" = (x - q*y) + (B - q*D) >= 0.
# This is a minor optimization to avoid division.
x_qy, B_qD = x - q*y, B - q*D
if x_qy + B_qD < 0:
break
# Next step in the Euclidean sequence.
x, y = y, x_qy
A, B, C, D = C, D, A - q*C, B_qD
# At this point the signs of the coefficients
# change and their roles are interchanged.
# A <= 0, B > 0, C > 0, D < 0,
# x' = x + A <= x < x" = x + B,
# y' = y + D < y < y" = y + C.
if y + D <= 0:
break
q = (x + B) // (y + D)
x_qy, A_qC = x - q*y, A - q*C
if x_qy + A_qC < 0:
break
x, y = y, x_qy
A, B, C, D = C, D, A_qC, B - q*D
# Now the conditions on top of the loop
# are again satisfied.
# A > 0, B < 0, C < 0, D > 0.
if B == 0:
# This can only happen when y == 0 in the beginning
# and the inner loop does nothing.
# Long division is forced.
a, b = b, a % b
continue
# Compute new long arguments using the coefficients.
a, b = A*a + B*b, C*a + D*b
# Small divisors. Finish with the standard algorithm.
while b:
a, b = b, a % b
return a
def ilcm(*args):
"""Computes integer least common multiple.
Examples
========
>>> from sympy.core.numbers import ilcm
>>> ilcm(5, 10)
10
>>> ilcm(7, 3)
21
>>> ilcm(5, 10, 15)
30
"""
if len(args) < 2:
raise TypeError(
'ilcm() takes at least 2 arguments (%s given)' % len(args))
if 0 in args:
return 0
a = args[0]
for b in args[1:]:
a = a // igcd(a, b) * b # since gcd(a,b) | a
return a
def igcdex(a, b):
"""Returns x, y, g such that g = x*a + y*b = gcd(a, b).
>>> from sympy.core.numbers import igcdex
>>> igcdex(2, 3)
(-1, 1, 1)
>>> igcdex(10, 12)
(-1, 1, 2)
>>> x, y, g = igcdex(100, 2004)
>>> x, y, g
(-20, 1, 4)
>>> x*100 + y*2004
4
"""
if (not a) and (not b):
return (0, 1, 0)
if not a:
return (0, b//abs(b), abs(b))
if not b:
return (a//abs(a), 0, abs(a))
if a < 0:
a, x_sign = -a, -1
else:
x_sign = 1
if b < 0:
b, y_sign = -b, -1
else:
y_sign = 1
x, y, r, s = 1, 0, 0, 1
while b:
(c, q) = (a % b, a // b)
(a, b, r, s, x, y) = (b, c, x - q*r, y - q*s, r, s)
return (x*x_sign, y*y_sign, a)
def mod_inverse(a, m):
"""
Return the number c such that, (a * c) = 1 (mod m)
where c has the same sign as m. If no such value exists,
a ValueError is raised.
Examples
========
>>> from sympy import S
>>> from sympy.core.numbers import mod_inverse
Suppose we wish to find multiplicative inverse x of
3 modulo 11. This is the same as finding x such
that 3 * x = 1 (mod 11). One value of x that satisfies
this congruence is 4. Because 3 * 4 = 12 and 12 = 1 (mod 11).
This is the value return by mod_inverse:
>>> mod_inverse(3, 11)
4
>>> mod_inverse(-3, 11)
7
When there is a common factor between the numerators of
``a`` and ``m`` the inverse does not exist:
>>> mod_inverse(2, 4)
Traceback (most recent call last):
...
ValueError: inverse of 2 mod 4 does not exist
>>> mod_inverse(S(2)/7, S(5)/2)
7/2
References
==========
- https://en.wikipedia.org/wiki/Modular_multiplicative_inverse
- https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm
"""
c = None
try:
a, m = as_int(a), as_int(m)
if m != 1 and m != -1:
x, y, g = igcdex(a, m)
if g == 1:
c = x % m
except ValueError:
a, m = sympify(a), sympify(m)
if not (a.is_number and m.is_number):
raise TypeError(filldedent('''
Expected numbers for arguments; symbolic `mod_inverse`
is not implemented
but symbolic expressions can be handled with the
similar function,
sympy.polys.polytools.invert'''))
big = (m > 1)
if not (big is S.true or big is S.false):
raise ValueError('m > 1 did not evaluate; try to simplify %s' % m)
elif big:
c = 1/a
if c is None:
raise ValueError('inverse of %s (mod %s) does not exist' % (a, m))
return c
class Number(AtomicExpr):
"""Represents atomic numbers in SymPy.
Floating point numbers are represented by the Float class.
Rational numbers (of any size) are represented by the Rational class.
Integer numbers (of any size) are represented by the Integer class.
Float and Rational are subclasses of Number; Integer is a subclass
of Rational.
For example, ``2/3`` is represented as ``Rational(2, 3)`` which is
a different object from the floating point number obtained with
Python division ``2/3``. Even for numbers that are exactly
represented in binary, there is a difference between how two forms,
such as ``Rational(1, 2)`` and ``Float(0.5)``, are used in SymPy.
The rational form is to be preferred in symbolic computations.
Other kinds of numbers, such as algebraic numbers ``sqrt(2)`` or
complex numbers ``3 + 4*I``, are not instances of Number class as
they are not atomic.
See Also
========
Float, Integer, Rational
"""
is_commutative = True
is_number = True
is_Number = True
__slots__ = []
# Used to make max(x._prec, y._prec) return x._prec when only x is a float
_prec = -1
def __new__(cls, *obj):
if len(obj) == 1:
obj = obj[0]
if isinstance(obj, Number):
return obj
if isinstance(obj, SYMPY_INTS):
return Integer(obj)
if isinstance(obj, tuple) and len(obj) == 2:
return Rational(*obj)
if isinstance(obj, (float, mpmath.mpf, decimal.Decimal)):
return Float(obj)
if isinstance(obj, string_types):
val = sympify(obj)
if isinstance(val, Number):
return val
else:
raise ValueError('String "%s" does not denote a Number' % obj)
msg = "expected str|int|long|float|Decimal|Number object but got %r"
raise TypeError(msg % type(obj).__name__)
def invert(self, other, *gens, **args):
from sympy.polys.polytools import invert
if getattr(other, 'is_number', True):
return mod_inverse(self, other)
return invert(self, other, *gens, **args)
def __divmod__(self, other):
from .containers import Tuple
from sympy.functions.elementary.complexes import sign
try:
other = Number(other)
except TypeError:
msg = "unsupported operand type(s) for divmod(): '%s' and '%s'"
raise TypeError(msg % (type(self).__name__, type(other).__name__))
if not other:
raise ZeroDivisionError('modulo by zero')
if self.is_Integer and other.is_Integer:
return Tuple(*divmod(self.p, other.p))
else:
rat = self/other
w = int(rat) if rat > 0 else int(rat) - 1
r = self - other*w
return Tuple(w, r)
def __rdivmod__(self, other):
try:
other = Number(other)
except TypeError:
msg = "unsupported operand type(s) for divmod(): '%s' and '%s'"
raise TypeError(msg % (type(other).__name__, type(self).__name__))
return divmod(other, self)
def __round__(self, *args):
return round(float(self), *args)
def _as_mpf_val(self, prec):
"""Evaluation of mpf tuple accurate to at least prec bits."""
raise NotImplementedError('%s needs ._as_mpf_val() method' %
(self.__class__.__name__))
def _eval_evalf(self, prec):
return Float._new(self._as_mpf_val(prec), prec)
def _as_mpf_op(self, prec):
prec = max(prec, self._prec)
return self._as_mpf_val(prec), prec
def __float__(self):
return mlib.to_float(self._as_mpf_val(53))
def floor(self):
raise NotImplementedError('%s needs .floor() method' %
(self.__class__.__name__))
def ceiling(self):
raise NotImplementedError('%s needs .ceiling() method' %
(self.__class__.__name__))
def _eval_conjugate(self):
return self
def _eval_order(self, *symbols):
from sympy import Order
# Order(5, x, y) -> Order(1,x,y)
return Order(S.One, *symbols)
def _eval_subs(self, old, new):
if old == -self:
return -new
return self # there is no other possibility
def _eval_is_finite(self):
return True
@classmethod
def class_key(cls):
return 1, 0, 'Number'
@cacheit
def sort_key(self, order=None):
return self.class_key(), (0, ()), (), self
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
return S.Infinity
elif other is S.NegativeInfinity:
return S.NegativeInfinity
return AtomicExpr.__add__(self, other)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
return S.NegativeInfinity
elif other is S.NegativeInfinity:
return S.Infinity
return AtomicExpr.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
if other is S.NaN:
return S.NaN
elif other is S.Infinity:
if self.is_zero:
return S.NaN
elif self.is_positive:
return S.Infinity
else:
return S.NegativeInfinity
elif other is S.NegativeInfinity:
if self.is_zero:
return S.NaN
elif self.is_positive:
return S.NegativeInfinity
else:
return S.Infinity
elif isinstance(other, Tuple):
return NotImplemented
return AtomicExpr.__mul__(self, other)
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
if other is S.NaN:
return S.NaN
elif other is S.Infinity or other is S.NegativeInfinity:
return S.Zero
return AtomicExpr.__div__(self, other)
__truediv__ = __div__
def __eq__(self, other):
raise NotImplementedError('%s needs .__eq__() method' %
(self.__class__.__name__))
def __ne__(self, other):
raise NotImplementedError('%s needs .__ne__() method' %
(self.__class__.__name__))
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
raise NotImplementedError('%s needs .__lt__() method' %
(self.__class__.__name__))
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
raise NotImplementedError('%s needs .__le__() method' %
(self.__class__.__name__))
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
return _sympify(other).__lt__(self)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
return _sympify(other).__le__(self)
def __hash__(self):
return super(Number, self).__hash__()
def is_constant(self, *wrt, **flags):
return True
def as_coeff_mul(self, *deps, **kwargs):
# a -> c*t
if self.is_Rational or not kwargs.pop('rational', True):
return self, tuple()
elif self.is_negative:
return S.NegativeOne, (-self,)
return S.One, (self,)
def as_coeff_add(self, *deps):
# a -> c + t
if self.is_Rational:
return self, tuple()
return S.Zero, (self,)
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product. """
if rational and not self.is_Rational:
return S.One, self
return (self, S.One) if self else (S.One, self)
def as_coeff_Add(self, rational=False):
"""Efficiently extract the coefficient of a summation. """
if not rational:
return self, S.Zero
return S.Zero, self
def gcd(self, other):
"""Compute GCD of `self` and `other`. """
from sympy.polys import gcd
return gcd(self, other)
def lcm(self, other):
"""Compute LCM of `self` and `other`. """
from sympy.polys import lcm
return lcm(self, other)
def cofactors(self, other):
"""Compute GCD and cofactors of `self` and `other`. """
from sympy.polys import cofactors
return cofactors(self, other)
class Float(Number):
"""Represent a floating-point number of arbitrary precision.
Examples
========
>>> from sympy import Float
>>> Float(3.5)
3.50000000000000
>>> Float(3)
3.00000000000000
Creating Floats from strings (and Python ``int`` and ``long``
types) will give a minimum precision of 15 digits, but the
precision will automatically increase to capture all digits
entered.
>>> Float(1)
1.00000000000000
>>> Float(10**20)
100000000000000000000.
>>> Float('1e20')
100000000000000000000.
However, *floating-point* numbers (Python ``float`` types) retain
only 15 digits of precision:
>>> Float(1e20)
1.00000000000000e+20
>>> Float(1.23456789123456789)
1.23456789123457
It may be preferable to enter high-precision decimal numbers
as strings:
Float('1.23456789123456789')
1.23456789123456789
The desired number of digits can also be specified:
>>> Float('1e-3', 3)
0.00100
>>> Float(100, 4)
100.0
Float can automatically count significant figures if a null string
is sent for the precision; space are also allowed in the string. (Auto-
counting is only allowed for strings, ints and longs).
>>> Float('123 456 789 . 123 456', '')
123456789.123456
>>> Float('12e-3', '')
0.012
>>> Float(3, '')
3.
If a number is written in scientific notation, only the digits before the
exponent are considered significant if a decimal appears, otherwise the
"e" signifies only how to move the decimal:
>>> Float('60.e2', '') # 2 digits significant
6.0e+3
>>> Float('60e2', '') # 4 digits significant
6000.
>>> Float('600e-2', '') # 3 digits significant
6.00
Notes
=====
Floats are inexact by their nature unless their value is a binary-exact
value.
>>> approx, exact = Float(.1, 1), Float(.125, 1)
For calculation purposes, evalf needs to be able to change the precision
but this will not increase the accuracy of the inexact value. The
following is the most accurate 5-digit approximation of a value of 0.1
that had only 1 digit of precision:
>>> approx.evalf(5)
0.099609
By contrast, 0.125 is exact in binary (as it is in base 10) and so it
can be passed to Float or evalf to obtain an arbitrary precision with
matching accuracy:
>>> Float(exact, 5)
0.12500
>>> exact.evalf(20)
0.12500000000000000000
Trying to make a high-precision Float from a float is not disallowed,
but one must keep in mind that the *underlying float* (not the apparent
decimal value) is being obtained with high precision. For example, 0.3
does not have a finite binary representation. The closest rational is
the fraction 5404319552844595/2**54. So if you try to obtain a Float of
0.3 to 20 digits of precision you will not see the same thing as 0.3
followed by 19 zeros:
>>> Float(0.3, 20)
0.29999999999999998890
If you want a 20-digit value of the decimal 0.3 (not the floating point
approximation of 0.3) you should send the 0.3 as a string. The underlying
representation is still binary but a higher precision than Python's float
is used:
>>> Float('0.3', 20)
0.30000000000000000000
Although you can increase the precision of an existing Float using Float
it will not increase the accuracy -- the underlying value is not changed:
>>> def show(f): # binary rep of Float
... from sympy import Mul, Pow
... s, m, e, b = f._mpf_
... v = Mul(int(m), Pow(2, int(e), evaluate=False), evaluate=False)
... print('%s at prec=%s' % (v, f._prec))
...
>>> t = Float('0.3', 3)
>>> show(t)
4915/2**14 at prec=13
>>> show(Float(t, 20)) # higher prec, not higher accuracy
4915/2**14 at prec=70
>>> show(Float(t, 2)) # lower prec
307/2**10 at prec=10
The same thing happens when evalf is used on a Float:
>>> show(t.evalf(20))
4915/2**14 at prec=70
>>> show(t.evalf(2))
307/2**10 at prec=10
Finally, Floats can be instantiated with an mpf tuple (n, c, p) to
produce the number (-1)**n*c*2**p:
>>> n, c, p = 1, 5, 0
>>> (-1)**n*c*2**p
-5
>>> Float((1, 5, 0))
-5.00000000000000
An actual mpf tuple also contains the number of bits in c as the last
element of the tuple:
>>> _._mpf_
(1, 5, 0, 3)
This is not needed for instantiation and is not the same thing as the
precision. The mpf tuple and the precision are two separate quantities
that Float tracks.
"""
__slots__ = ['_mpf_', '_prec']
# A Float represents many real numbers,
# both rational and irrational.
is_rational = None
is_irrational = None
is_number = True
is_real = True
is_Float = True
def __new__(cls, num, dps=None, prec=None, precision=None):
if prec is not None:
SymPyDeprecationWarning(
feature="Using 'prec=XX' to denote decimal precision",
useinstead="'dps=XX' for decimal precision and 'precision=XX' "\
"for binary precision",
issue=12820,
deprecated_since_version="1.1").warn()
dps = prec
del prec # avoid using this deprecated kwarg
if dps is not None and precision is not None:
raise ValueError('Both decimal and binary precision supplied. '
'Supply only one. ')
if isinstance(num, string_types):
num = num.replace(' ', '')
if num.startswith('.') and len(num) > 1:
num = '0' + num
elif num.startswith('-.') and len(num) > 2:
num = '-0.' + num[2:]
elif isinstance(num, float) and num == 0:
num = '0'
elif isinstance(num, (SYMPY_INTS, Integer)):
num = str(num) # faster than mlib.from_int
elif num is S.Infinity:
num = '+inf'
elif num is S.NegativeInfinity:
num = '-inf'
elif type(num).__module__ == 'numpy': # support for numpy datatypes
num = _convert_numpy_types(num)
elif isinstance(num, mpmath.mpf):
if precision is None:
if dps is None:
precision = num.context.prec
num = num._mpf_
if dps is None and precision is None:
dps = 15
if isinstance(num, Float):
return num
if isinstance(num, string_types) and _literal_float(num):
try:
Num = decimal.Decimal(num)
except decimal.InvalidOperation:
pass
else:
isint = '.' not in num
num, dps = _decimal_to_Rational_prec(Num)
if num.is_Integer and isint:
dps = max(dps, len(str(num).lstrip('-')))
dps = max(15, dps)
precision = mlib.libmpf.dps_to_prec(dps)
elif precision == '' and dps is None or precision is None and dps == '':
if not isinstance(num, string_types):
raise ValueError('The null string can only be used when '
'the number to Float is passed as a string or an integer.')
ok = None
if _literal_float(num):
try:
Num = decimal.Decimal(num)
except decimal.InvalidOperation:
pass
else:
isint = '.' not in num
num, dps = _decimal_to_Rational_prec(Num)
if num.is_Integer and isint:
dps = max(dps, len(str(num).lstrip('-')))
precision = mlib.libmpf.dps_to_prec(dps)
ok = True
if ok is None:
raise ValueError('string-float not recognized: %s' % num)
# decimal precision(dps) is set and maybe binary precision(precision)
# as well.From here on binary precision is used to compute the Float.
# Hence, if supplied use binary precision else translate from decimal
# precision.
if precision is None or precision == '':
precision = mlib.libmpf.dps_to_prec(dps)
precision = int(precision)
if isinstance(num, float):
_mpf_ = mlib.from_float(num, precision, rnd)
elif isinstance(num, string_types):
_mpf_ = mlib.from_str(num, precision, rnd)
elif isinstance(num, decimal.Decimal):
if num.is_finite():
_mpf_ = mlib.from_str(str(num), precision, rnd)
elif num.is_nan():
_mpf_ = _mpf_nan
elif num.is_infinite():
if num > 0:
_mpf_ = _mpf_inf
else:
_mpf_ = _mpf_ninf
else:
raise ValueError("unexpected decimal value %s" % str(num))
elif isinstance(num, tuple) and len(num) in (3, 4):
if type(num[1]) is str:
# it's a hexadecimal (coming from a pickled object)
# assume that it is in standard form
num = list(num)
# If we're loading an object pickled in Python 2 into
# Python 3, we may need to strip a tailing 'L' because
# of a shim for int on Python 3, see issue #13470.
if num[1].endswith('L'):
num[1] = num[1][:-1]
num[1] = MPZ(num[1], 16)
_mpf_ = tuple(num)
else:
if len(num) == 4:
# handle normalization hack
return Float._new(num, precision)
else:
return (S.NegativeOne**num[0]*num[1]*S(2)**num[2]).evalf(precision)
else:
try:
_mpf_ = num._as_mpf_val(precision)
except (NotImplementedError, AttributeError):
_mpf_ = mpmath.mpf(num, prec=precision)._mpf_
# special cases
if _mpf_ == _mpf_zero:
pass # we want a Float
elif _mpf_ == _mpf_nan:
return S.NaN
obj = Expr.__new__(cls)
obj._mpf_ = _mpf_
obj._prec = precision
return obj
@classmethod
def _new(cls, _mpf_, _prec):
# special cases
if _mpf_ == _mpf_zero:
return S.Zero # XXX this is different from Float which gives 0.0
elif _mpf_ == _mpf_nan:
return S.NaN
obj = Expr.__new__(cls)
obj._mpf_ = mpf_norm(_mpf_, _prec)
# XXX: Should this be obj._prec = obj._mpf_[3]?
obj._prec = _prec
return obj
# mpz can't be pickled
def __getnewargs__(self):
return (mlib.to_pickable(self._mpf_),)
def __getstate__(self):
return {'_prec': self._prec}
def _hashable_content(self):
return (self._mpf_, self._prec)
def floor(self):
return Integer(int(mlib.to_int(
mlib.mpf_floor(self._mpf_, self._prec))))
def ceiling(self):
return Integer(int(mlib.to_int(
mlib.mpf_ceil(self._mpf_, self._prec))))
@property
def num(self):
return mpmath.mpf(self._mpf_)
def _as_mpf_val(self, prec):
rv = mpf_norm(self._mpf_, prec)
if rv != self._mpf_ and self._prec == prec:
debug(self._mpf_, rv)
return rv
def _as_mpf_op(self, prec):
return self._mpf_, max(prec, self._prec)
def _eval_is_finite(self):
if self._mpf_ in (_mpf_inf, _mpf_ninf):
return False
return True
def _eval_is_infinite(self):
if self._mpf_ in (_mpf_inf, _mpf_ninf):
return True
return False
def _eval_is_integer(self):
return self._mpf_ == _mpf_zero
def _eval_is_negative(self):
if self._mpf_ == _mpf_ninf:
return True
if self._mpf_ == _mpf_inf:
return False
return self.num < 0
def _eval_is_positive(self):
if self._mpf_ == _mpf_inf:
return True
if self._mpf_ == _mpf_ninf:
return False
return self.num > 0
def _eval_is_zero(self):
return self._mpf_ == _mpf_zero
def __nonzero__(self):
return self._mpf_ != _mpf_zero
__bool__ = __nonzero__
def __neg__(self):
return Float._new(mlib.mpf_neg(self._mpf_), self._prec)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_add(self._mpf_, rhs, prec, rnd), prec)
return Number.__add__(self, other)
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_sub(self._mpf_, rhs, prec, rnd), prec)
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number) and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mul(self._mpf_, rhs, prec, rnd), prec)
return Number.__mul__(self, other)
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if isinstance(other, Number) and other != 0 and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_div(self._mpf_, rhs, prec, rnd), prec)
return Number.__div__(self, other)
__truediv__ = __div__
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if isinstance(other, Rational) and other.q != 1 and global_evaluate[0]:
# calculate mod with Rationals, *then* round the result
return Float(Rational.__mod__(Rational(self), other),
precision=self._prec)
if isinstance(other, Float) and global_evaluate[0]:
r = self/other
if r == int(r):
return Float(0, precision=max(self._prec, other._prec))
if isinstance(other, Number) and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mod(self._mpf_, rhs, prec, rnd), prec)
return Number.__mod__(self, other)
@_sympifyit('other', NotImplemented)
def __rmod__(self, other):
if isinstance(other, Float) and global_evaluate[0]:
return other.__mod__(self)
if isinstance(other, Number) and global_evaluate[0]:
rhs, prec = other._as_mpf_op(self._prec)
return Float._new(mlib.mpf_mod(rhs, self._mpf_, prec, rnd), prec)
return Number.__rmod__(self, other)
def _eval_power(self, expt):
"""
expt is symbolic object but not equal to 0, 1
(-p)**r -> exp(r*log(-p)) -> exp(r*(log(p) + I*Pi)) ->
-> p**r*(sin(Pi*r) + cos(Pi*r)*I)
"""
if self == 0:
if expt.is_positive:
return S.Zero
if expt.is_negative:
return Float('inf')
if isinstance(expt, Number):
if isinstance(expt, Integer):
prec = self._prec
return Float._new(
mlib.mpf_pow_int(self._mpf_, expt.p, prec, rnd), prec)
elif isinstance(expt, Rational) and \
expt.p == 1 and expt.q % 2 and self.is_negative:
return Pow(S.NegativeOne, expt, evaluate=False)*(
-self)._eval_power(expt)
expt, prec = expt._as_mpf_op(self._prec)
mpfself = self._mpf_
try:
y = mpf_pow(mpfself, expt, prec, rnd)
return Float._new(y, prec)
except mlib.ComplexResult:
re, im = mlib.mpc_pow(
(mpfself, _mpf_zero), (expt, _mpf_zero), prec, rnd)
return Float._new(re, prec) + \
Float._new(im, prec)*S.ImaginaryUnit
def __abs__(self):
return Float._new(mlib.mpf_abs(self._mpf_), self._prec)
def __int__(self):
if self._mpf_ == _mpf_zero:
return 0
return int(mlib.to_int(self._mpf_)) # uses round_fast = round_down
__long__ = __int__
def __eq__(self, other):
if isinstance(other, float):
# coerce to Float at same precision
o = Float(other)
try:
ompf = o._as_mpf_val(self._prec)
except ValueError:
return False
return bool(mlib.mpf_eq(self._mpf_, ompf))
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_NumberSymbol:
if other.is_irrational:
return False
return other.__eq__(self)
if other.is_Float:
return bool(mlib.mpf_eq(self._mpf_, other._mpf_))
if other.is_Number:
# numbers should compare at the same precision;
# all _as_mpf_val routines should be sure to abide
# by the request to change the prec if necessary; if
# they don't, the equality test will fail since it compares
# the mpf tuples
ompf = other._as_mpf_val(self._prec)
return bool(mlib.mpf_eq(self._mpf_, ompf))
return False # Float != non-Number
def __ne__(self, other):
return not self == other
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
if other.is_NumberSymbol:
return other.__lt__(self)
if other.is_Rational and not other.is_Integer:
self *= other.q
other = _sympify(other.p)
elif other.is_comparable:
other = other.evalf()
if other.is_Number and other is not S.NaN:
return _sympify(bool(
mlib.mpf_gt(self._mpf_, other._as_mpf_val(self._prec))))
return Expr.__gt__(self, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
if other.is_NumberSymbol:
return other.__le__(self)
if other.is_Rational and not other.is_Integer:
self *= other.q
other = _sympify(other.p)
elif other.is_comparable:
other = other.evalf()
if other.is_Number and other is not S.NaN:
return _sympify(bool(
mlib.mpf_ge(self._mpf_, other._as_mpf_val(self._prec))))
return Expr.__ge__(self, other)
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
if other.is_NumberSymbol:
return other.__gt__(self)
if other.is_Rational and not other.is_Integer:
self *= other.q
other = _sympify(other.p)
elif other.is_comparable:
other = other.evalf()
if other.is_Number and other is not S.NaN:
return _sympify(bool(
mlib.mpf_lt(self._mpf_, other._as_mpf_val(self._prec))))
return Expr.__lt__(self, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
if other.is_NumberSymbol:
return other.__ge__(self)
if other.is_Rational and not other.is_Integer:
self *= other.q
other = _sympify(other.p)
elif other.is_comparable:
other = other.evalf()
if other.is_Number and other is not S.NaN:
return _sympify(bool(
mlib.mpf_le(self._mpf_, other._as_mpf_val(self._prec))))
return Expr.__le__(self, other)
def __hash__(self):
return super(Float, self).__hash__()
def epsilon_eq(self, other, epsilon="1e-15"):
return abs(self - other) < Float(epsilon)
def _sage_(self):
import sage.all as sage
return sage.RealNumber(str(self))
def __format__(self, format_spec):
return format(decimal.Decimal(str(self)), format_spec)
# Add sympify converters
converter[float] = converter[decimal.Decimal] = Float
# this is here to work nicely in Sage
RealNumber = Float
class Rational(Number):
"""Represents rational numbers (p/q) of any size.
Examples
========
>>> from sympy import Rational, nsimplify, S, pi
>>> Rational(1, 2)
1/2
Rational is unprejudiced in accepting input. If a float is passed, the
underlying value of the binary representation will be returned:
>>> Rational(.5)
1/2
>>> Rational(.2)
3602879701896397/18014398509481984
If the simpler representation of the float is desired then consider
limiting the denominator to the desired value or convert the float to
a string (which is roughly equivalent to limiting the denominator to
10**12):
>>> Rational(str(.2))
1/5
>>> Rational(.2).limit_denominator(10**12)
1/5
An arbitrarily precise Rational is obtained when a string literal is
passed:
>>> Rational("1.23")
123/100
>>> Rational('1e-2')
1/100
>>> Rational(".1")
1/10
>>> Rational('1e-2/3.2')
1/320
The conversion of other types of strings can be handled by
the sympify() function, and conversion of floats to expressions
or simple fractions can be handled with nsimplify:
>>> S('.[3]') # repeating digits in brackets
1/3
>>> S('3**2/10') # general expressions
9/10
>>> nsimplify(.3) # numbers that have a simple form
3/10
But if the input does not reduce to a literal Rational, an error will
be raised:
>>> Rational(pi)
Traceback (most recent call last):
...
TypeError: invalid input: pi
Low-level
---------
Access numerator and denominator as .p and .q:
>>> r = Rational(3, 4)
>>> r
3/4
>>> r.p
3
>>> r.q
4
Note that p and q return integers (not SymPy Integers) so some care
is needed when using them in expressions:
>>> r.p/r.q
0.75
See Also
========
sympify, sympy.simplify.simplify.nsimplify
"""
is_real = True
is_integer = False
is_rational = True
is_number = True
__slots__ = ['p', 'q']
is_Rational = True
@cacheit
def __new__(cls, p, q=None, gcd=None):
if q is None:
if isinstance(p, Rational):
return p
if isinstance(p, SYMPY_INTS):
pass
else:
if isinstance(p, (float, Float)):
return Rational(*_as_integer_ratio(p))
if not isinstance(p, string_types):
try:
p = sympify(p)
except (SympifyError, SyntaxError):
pass # error will raise below
else:
if p.count('/') > 1:
raise TypeError('invalid input: %s' % p)
p = p.replace(' ', '')
pq = p.rsplit('/', 1)
if len(pq) == 2:
p, q = pq
fp = fractions.Fraction(p)
fq = fractions.Fraction(q)
p = fp/fq
try:
p = fractions.Fraction(p)
except ValueError:
pass # error will raise below
else:
return Rational(p.numerator, p.denominator, 1)
if not isinstance(p, Rational):
raise TypeError('invalid input: %s' % p)
q = 1
gcd = 1
else:
p = Rational(p)
q = Rational(q)
if isinstance(q, Rational):
p *= q.q
q = q.p
if isinstance(p, Rational):
q *= p.q
p = p.p
# p and q are now integers
if q == 0:
if p == 0:
if _errdict["divide"]:
raise ValueError("Indeterminate 0/0")
else:
return S.NaN
return S.ComplexInfinity
if q < 0:
q = -q
p = -p
if not gcd:
gcd = igcd(abs(p), q)
if gcd > 1:
p //= gcd
q //= gcd
if q == 1:
return Integer(p)
if p == 1 and q == 2:
return S.Half
obj = Expr.__new__(cls)
obj.p = p
obj.q = q
return obj
def limit_denominator(self, max_denominator=1000000):
"""Closest Rational to self with denominator at most max_denominator.
>>> from sympy import Rational
>>> Rational('3.141592653589793').limit_denominator(10)
22/7
>>> Rational('3.141592653589793').limit_denominator(100)
311/99
"""
f = fractions.Fraction(self.p, self.q)
return Rational(f.limit_denominator(fractions.Fraction(int(max_denominator))))
def __getnewargs__(self):
return (self.p, self.q)
def _hashable_content(self):
return (self.p, self.q)
def _eval_is_positive(self):
return self.p > 0
def _eval_is_zero(self):
return self.p == 0
def __neg__(self):
return Rational(-self.p, self.q)
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
return Rational(self.p + self.q*other.p, self.q, 1)
elif isinstance(other, Rational):
#TODO: this can probably be optimized more
return Rational(self.p*other.q + self.q*other.p, self.q*other.q)
elif isinstance(other, Float):
return other + self
else:
return Number.__add__(self, other)
return Number.__add__(self, other)
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
return Rational(self.p - self.q*other.p, self.q, 1)
elif isinstance(other, Rational):
return Rational(self.p*other.q - self.q*other.p, self.q*other.q)
elif isinstance(other, Float):
return -other + self
else:
return Number.__sub__(self, other)
return Number.__sub__(self, other)
@_sympifyit('other', NotImplemented)
def __rsub__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
return Rational(self.q*other.p - self.p, self.q, 1)
elif isinstance(other, Rational):
return Rational(self.q*other.p - self.p*other.q, self.q*other.q)
elif isinstance(other, Float):
return -self + other
else:
return Number.__rsub__(self, other)
return Number.__rsub__(self, other)
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
return Rational(self.p*other.p, self.q, igcd(other.p, self.q))
elif isinstance(other, Rational):
return Rational(self.p*other.p, self.q*other.q, igcd(self.p, other.q)*igcd(self.q, other.p))
elif isinstance(other, Float):
return other*self
else:
return Number.__mul__(self, other)
return Number.__mul__(self, other)
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
if self.p and other.p == S.Zero:
return S.ComplexInfinity
else:
return Rational(self.p, self.q*other.p, igcd(self.p, other.p))
elif isinstance(other, Rational):
return Rational(self.p*other.q, self.q*other.p, igcd(self.p, other.p)*igcd(self.q, other.q))
elif isinstance(other, Float):
return self*(1/other)
else:
return Number.__div__(self, other)
return Number.__div__(self, other)
@_sympifyit('other', NotImplemented)
def __rdiv__(self, other):
if global_evaluate[0]:
if isinstance(other, Integer):
return Rational(other.p*self.q, self.p, igcd(self.p, other.p))
elif isinstance(other, Rational):
return Rational(other.p*self.q, other.q*self.p, igcd(self.p, other.p)*igcd(self.q, other.q))
elif isinstance(other, Float):
return other*(1/self)
else:
return Number.__rdiv__(self, other)
return Number.__rdiv__(self, other)
__truediv__ = __div__
@_sympifyit('other', NotImplemented)
def __mod__(self, other):
if global_evaluate[0]:
if isinstance(other, Rational):
n = (self.p*other.q) // (other.p*self.q)
return Rational(self.p*other.q - n*other.p*self.q, self.q*other.q)
if isinstance(other, Float):
# calculate mod with Rationals, *then* round the answer
return Float(self.__mod__(Rational(other)),
precision=other._prec)
return Number.__mod__(self, other)
return Number.__mod__(self, other)
@_sympifyit('other', NotImplemented)
def __rmod__(self, other):
if isinstance(other, Rational):
return Rational.__mod__(other, self)
return Number.__rmod__(self, other)
def _eval_power(self, expt):
if isinstance(expt, Number):
if isinstance(expt, Float):
return self._eval_evalf(expt._prec)**expt
if expt.is_negative:
# (3/4)**-2 -> (4/3)**2
ne = -expt
if (ne is S.One):
return Rational(self.q, self.p)
if self.is_negative:
return S.NegativeOne**expt*Rational(self.q, -self.p)**ne
else:
return Rational(self.q, self.p)**ne
if expt is S.Infinity: # -oo already caught by test for negative
if self.p > self.q:
# (3/2)**oo -> oo
return S.Infinity
if self.p < -self.q:
# (-3/2)**oo -> oo + I*oo
return S.Infinity + S.Infinity*S.ImaginaryUnit
return S.Zero
if isinstance(expt, Integer):
# (4/3)**2 -> 4**2 / 3**2
return Rational(self.p**expt.p, self.q**expt.p, 1)
if isinstance(expt, Rational):
if self.p != 1:
# (4/3)**(5/6) -> 4**(5/6)*3**(-5/6)
return Integer(self.p)**expt*Integer(self.q)**(-expt)
# as the above caught negative self.p, now self is positive
return Integer(self.q)**Rational(
expt.p*(expt.q - 1), expt.q) / \
Integer(self.q)**Integer(expt.p)
if self.is_negative and expt.is_even:
return (-self)**expt
return
def _as_mpf_val(self, prec):
return mlib.from_rational(self.p, self.q, prec, rnd)
def _mpmath_(self, prec, rnd):
return mpmath.make_mpf(mlib.from_rational(self.p, self.q, prec, rnd))
def __abs__(self):
return Rational(abs(self.p), self.q)
def __int__(self):
p, q = self.p, self.q
if p < 0:
return -int(-p//q)
return int(p//q)
__long__ = __int__
def floor(self):
return Integer(self.p // self.q)
def ceiling(self):
return -Integer(-self.p // self.q)
def __eq__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if other.is_NumberSymbol:
if other.is_irrational:
return False
return other.__eq__(self)
if other.is_Number:
if other.is_Rational:
# a Rational is always in reduced form so will never be 2/4
# so we can just check equivalence of args
return self.p == other.p and self.q == other.q
if other.is_Float:
return mlib.mpf_eq(self._as_mpf_val(other._prec), other._mpf_)
return False
def __ne__(self, other):
return not self == other
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
if other.is_NumberSymbol:
return other.__lt__(self)
expr = self
if other.is_Number:
if other.is_Rational:
return _sympify(bool(self.p*other.q > self.q*other.p))
if other.is_Float:
return _sympify(bool(mlib.mpf_gt(
self._as_mpf_val(other._prec), other._mpf_)))
elif other.is_number and other.is_real:
expr, other = Integer(self.p), self.q*other
return Expr.__gt__(expr, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
if other.is_NumberSymbol:
return other.__le__(self)
expr = self
if other.is_Number:
if other.is_Rational:
return _sympify(bool(self.p*other.q >= self.q*other.p))
if other.is_Float:
return _sympify(bool(mlib.mpf_ge(
self._as_mpf_val(other._prec), other._mpf_)))
elif other.is_number and other.is_real:
expr, other = Integer(self.p), self.q*other
return Expr.__ge__(expr, other)
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
if other.is_NumberSymbol:
return other.__gt__(self)
expr = self
if other.is_Number:
if other.is_Rational:
return _sympify(bool(self.p*other.q < self.q*other.p))
if other.is_Float:
return _sympify(bool(mlib.mpf_lt(
self._as_mpf_val(other._prec), other._mpf_)))
elif other.is_number and other.is_real:
expr, other = Integer(self.p), self.q*other
return Expr.__lt__(expr, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
expr = self
if other.is_NumberSymbol:
return other.__ge__(self)
elif other.is_Number:
if other.is_Rational:
return _sympify(bool(self.p*other.q <= self.q*other.p))
if other.is_Float:
return _sympify(bool(mlib.mpf_le(
self._as_mpf_val(other._prec), other._mpf_)))
elif other.is_number and other.is_real:
expr, other = Integer(self.p), self.q*other
return Expr.__le__(expr, other)
def __hash__(self):
return super(Rational, self).__hash__()
def factors(self, limit=None, use_trial=True, use_rho=False,
use_pm1=False, verbose=False, visual=False):
"""A wrapper to factorint which return factors of self that are
smaller than limit (or cheap to compute). Special methods of
factoring are disabled by default so that only trial division is used.
"""
from sympy.ntheory import factorrat
return factorrat(self, limit=limit, use_trial=use_trial,
use_rho=use_rho, use_pm1=use_pm1,
verbose=verbose).copy()
@_sympifyit('other', NotImplemented)
def gcd(self, other):
if isinstance(other, Rational):
if other is S.Zero:
return other
return Rational(
Integer(igcd(self.p, other.p)),
Integer(ilcm(self.q, other.q)))
return Number.gcd(self, other)
@_sympifyit('other', NotImplemented)
def lcm(self, other):
if isinstance(other, Rational):
return Rational(
self.p // igcd(self.p, other.p) * other.p,
igcd(self.q, other.q))
return Number.lcm(self, other)
def as_numer_denom(self):
return Integer(self.p), Integer(self.q)
def _sage_(self):
import sage.all as sage
return sage.Integer(self.p)/sage.Integer(self.q)
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self.
Examples
========
>>> from sympy import S
>>> (S(-3)/2).as_content_primitive()
(3/2, -1)
See docstring of Expr.as_content_primitive for more examples.
"""
if self:
if self.is_positive:
return self, S.One
return -self, S.NegativeOne
return S.One, self
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product. """
return self, S.One
def as_coeff_Add(self, rational=False):
"""Efficiently extract the coefficient of a summation. """
return self, S.Zero
# int -> Integer
_intcache = {}
# TODO move this tracing facility to sympy/core/trace.py ?
def _intcache_printinfo():
ints = sorted(_intcache.keys())
nhit = _intcache_hits
nmiss = _intcache_misses
if nhit == 0 and nmiss == 0:
print()
print('Integer cache statistic was not collected')
return
miss_ratio = float(nmiss) / (nhit + nmiss)
print()
print('Integer cache statistic')
print('-----------------------')
print()
print('#items: %i' % len(ints))
print()
print(' #hit #miss #total')
print()
print('%5i %5i (%7.5f %%) %5i' % (
nhit, nmiss, miss_ratio*100, nhit + nmiss)
)
print()
print(ints)
_intcache_hits = 0
_intcache_misses = 0
def int_trace(f):
import os
if os.getenv('SYMPY_TRACE_INT', 'no').lower() != 'yes':
return f
def Integer_tracer(cls, i):
global _intcache_hits, _intcache_misses
try:
_intcache_hits += 1
return _intcache[i]
except KeyError:
_intcache_hits -= 1
_intcache_misses += 1
return f(cls, i)
# also we want to hook our _intcache_printinfo into sys.atexit
import atexit
atexit.register(_intcache_printinfo)
return Integer_tracer
class Integer(Rational):
"""Represents integer numbers of any size.
Examples
========
>>> from sympy import Integer
>>> Integer(3)
3
If a float or a rational is passed to Integer, the fractional part
will be discarded; the effect is of rounding toward zero.
>>> Integer(3.8)
3
>>> Integer(-3.8)
-3
A string is acceptable input if it can be parsed as an integer:
>>> Integer("9" * 20)
99999999999999999999
It is rarely needed to explicitly instantiate an Integer, because
Python integers are automatically converted to Integer when they
are used in SymPy expressions.
"""
q = 1
is_integer = True
is_number = True
is_Integer = True
__slots__ = ['p']
def _as_mpf_val(self, prec):
return mlib.from_int(self.p, prec, rnd)
def _mpmath_(self, prec, rnd):
return mpmath.make_mpf(self._as_mpf_val(prec))
# TODO caching with decorator, but not to degrade performance
@int_trace
def __new__(cls, i):
if isinstance(i, string_types):
i = i.replace(' ', '')
# whereas we cannot, in general, make a Rational from an
# arbitrary expression, we can make an Integer unambiguously
# (except when a non-integer expression happens to round to
# an integer). So we proceed by taking int() of the input and
# let the int routines determine whether the expression can
# be made into an int or whether an error should be raised.
try:
ival = int(i)
except TypeError:
raise TypeError(
"Argument of Integer should be of numeric type, got %s." % i)
try:
return _intcache[ival]
except KeyError:
# We only work with well-behaved integer types. This converts, for
# example, numpy.int32 instances.
obj = Expr.__new__(cls)
obj.p = ival
_intcache[ival] = obj
return obj
def __getnewargs__(self):
return (self.p,)
# Arithmetic operations are here for efficiency
def __int__(self):
return self.p
__long__ = __int__
def floor(self):
return Integer(self.p)
def ceiling(self):
return Integer(self.p)
def __neg__(self):
return Integer(-self.p)
def __abs__(self):
if self.p >= 0:
return self
else:
return Integer(-self.p)
def __divmod__(self, other):
from .containers import Tuple
if isinstance(other, Integer) and global_evaluate[0]:
return Tuple(*(divmod(self.p, other.p)))
else:
return Number.__divmod__(self, other)
def __rdivmod__(self, other):
from .containers import Tuple
if isinstance(other, integer_types) and global_evaluate[0]:
return Tuple(*(divmod(other, self.p)))
else:
try:
other = Number(other)
except TypeError:
msg = "unsupported operand type(s) for divmod(): '%s' and '%s'"
oname = type(other).__name__
sname = type(self).__name__
raise TypeError(msg % (oname, sname))
return Number.__divmod__(other, self)
# TODO make it decorator + bytecodehacks?
def __add__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(self.p + other)
elif isinstance(other, Integer):
return Integer(self.p + other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.q + other.p, other.q, 1)
return Rational.__add__(self, other)
else:
return Add(self, other)
def __radd__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(other + self.p)
elif isinstance(other, Rational):
return Rational(other.p + self.p*other.q, other.q, 1)
return Rational.__radd__(self, other)
return Rational.__radd__(self, other)
def __sub__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(self.p - other)
elif isinstance(other, Integer):
return Integer(self.p - other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.q - other.p, other.q, 1)
return Rational.__sub__(self, other)
return Rational.__sub__(self, other)
def __rsub__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(other - self.p)
elif isinstance(other, Rational):
return Rational(other.p - self.p*other.q, other.q, 1)
return Rational.__rsub__(self, other)
return Rational.__rsub__(self, other)
def __mul__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(self.p*other)
elif isinstance(other, Integer):
return Integer(self.p*other.p)
elif isinstance(other, Rational):
return Rational(self.p*other.p, other.q, igcd(self.p, other.q))
return Rational.__mul__(self, other)
return Rational.__mul__(self, other)
def __rmul__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(other*self.p)
elif isinstance(other, Rational):
return Rational(other.p*self.p, other.q, igcd(self.p, other.q))
return Rational.__rmul__(self, other)
return Rational.__rmul__(self, other)
def __mod__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(self.p % other)
elif isinstance(other, Integer):
return Integer(self.p % other.p)
return Rational.__mod__(self, other)
return Rational.__mod__(self, other)
def __rmod__(self, other):
if global_evaluate[0]:
if isinstance(other, integer_types):
return Integer(other % self.p)
elif isinstance(other, Integer):
return Integer(other.p % self.p)
return Rational.__rmod__(self, other)
return Rational.__rmod__(self, other)
def __eq__(self, other):
if isinstance(other, integer_types):
return (self.p == other)
elif isinstance(other, Integer):
return (self.p == other.p)
return Rational.__eq__(self, other)
def __ne__(self, other):
return not self == other
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
if other.is_Integer:
return _sympify(self.p > other.p)
return Rational.__gt__(self, other)
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
if other.is_Integer:
return _sympify(self.p < other.p)
return Rational.__lt__(self, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
if other.is_Integer:
return _sympify(self.p >= other.p)
return Rational.__ge__(self, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
if other.is_Integer:
return _sympify(self.p <= other.p)
return Rational.__le__(self, other)
def __hash__(self):
return hash(self.p)
def __index__(self):
return self.p
########################################
def _eval_is_odd(self):
return bool(self.p % 2)
def _eval_power(self, expt):
"""
Tries to do some simplifications on self**expt
Returns None if no further simplifications can be done
When exponent is a fraction (so we have for example a square root),
we try to find a simpler representation by factoring the argument
up to factors of 2**15, e.g.
- sqrt(4) becomes 2
- sqrt(-4) becomes 2*I
- (2**(3+7)*3**(6+7))**Rational(1,7) becomes 6*18**(3/7)
Further simplification would require a special call to factorint on
the argument which is not done here for sake of speed.
"""
from sympy import perfect_power
if expt is S.Infinity:
if self.p > S.One:
return S.Infinity
# cases -1, 0, 1 are done in their respective classes
return S.Infinity + S.ImaginaryUnit*S.Infinity
if expt is S.NegativeInfinity:
return Rational(1, self)**S.Infinity
if not isinstance(expt, Number):
# simplify when expt is even
# (-2)**k --> 2**k
if self.is_negative and expt.is_even:
return (-self)**expt
if isinstance(expt, Float):
# Rational knows how to exponentiate by a Float
return super(Integer, self)._eval_power(expt)
if not isinstance(expt, Rational):
return
if expt is S.Half and self.is_negative:
# we extract I for this special case since everyone is doing so
return S.ImaginaryUnit*Pow(-self, expt)
if expt.is_negative:
# invert base and change sign on exponent
ne = -expt
if self.is_negative:
return S.NegativeOne**expt*Rational(1, -self)**ne
else:
return Rational(1, self.p)**ne
# see if base is a perfect root, sqrt(4) --> 2
x, xexact = integer_nthroot(abs(self.p), expt.q)
if xexact:
# if it's a perfect root we've finished
result = Integer(x**abs(expt.p))
if self.is_negative:
result *= S.NegativeOne**expt
return result
# The following is an algorithm where we collect perfect roots
# from the factors of base.
# if it's not an nth root, it still might be a perfect power
b_pos = int(abs(self.p))
p = perfect_power(b_pos)
if p is not False:
dict = {p[0]: p[1]}
else:
dict = Integer(b_pos).factors(limit=2**15)
# now process the dict of factors
out_int = 1 # integer part
out_rad = 1 # extracted radicals
sqr_int = 1
sqr_gcd = 0
sqr_dict = {}
for prime, exponent in dict.items():
exponent *= expt.p
# remove multiples of expt.q: (2**12)**(1/10) -> 2*(2**2)**(1/10)
div_e, div_m = divmod(exponent, expt.q)
if div_e > 0:
out_int *= prime**div_e
if div_m > 0:
# see if the reduced exponent shares a gcd with e.q
# (2**2)**(1/10) -> 2**(1/5)
g = igcd(div_m, expt.q)
if g != 1:
out_rad *= Pow(prime, Rational(div_m//g, expt.q//g))
else:
sqr_dict[prime] = div_m
# identify gcd of remaining powers
for p, ex in sqr_dict.items():
if sqr_gcd == 0:
sqr_gcd = ex
else:
sqr_gcd = igcd(sqr_gcd, ex)
if sqr_gcd == 1:
break
for k, v in sqr_dict.items():
sqr_int *= k**(v//sqr_gcd)
if sqr_int == b_pos and out_int == 1 and out_rad == 1:
result = None
else:
result = out_int*out_rad*Pow(sqr_int, Rational(sqr_gcd, expt.q))
if self.is_negative:
result *= Pow(S.NegativeOne, expt)
return result
def _eval_is_prime(self):
from sympy.ntheory import isprime
return isprime(self)
def _eval_is_composite(self):
if self > 1:
return fuzzy_not(self.is_prime)
else:
return False
def as_numer_denom(self):
return self, S.One
def __floordiv__(self, other):
return Integer(self.p // Integer(other).p)
def __rfloordiv__(self, other):
return Integer(Integer(other).p // self.p)
# Add sympify converters
for i_type in integer_types:
converter[i_type] = Integer
class AlgebraicNumber(Expr):
"""Class for representing algebraic numbers in SymPy. """
__slots__ = ['rep', 'root', 'alias', 'minpoly']
is_AlgebraicNumber = True
is_algebraic = True
is_number = True
def __new__(cls, expr, coeffs=None, alias=None, **args):
"""Construct a new algebraic number. """
from sympy import Poly
from sympy.polys.polyclasses import ANP, DMP
from sympy.polys.numberfields import minimal_polynomial
from sympy.core.symbol import Symbol
expr = sympify(expr)
if isinstance(expr, (tuple, Tuple)):
minpoly, root = expr
if not minpoly.is_Poly:
minpoly = Poly(minpoly)
elif expr.is_AlgebraicNumber:
minpoly, root = expr.minpoly, expr.root
else:
minpoly, root = minimal_polynomial(
expr, args.get('gen'), polys=True), expr
dom = minpoly.get_domain()
if coeffs is not None:
if not isinstance(coeffs, ANP):
rep = DMP.from_sympy_list(sympify(coeffs), 0, dom)
scoeffs = Tuple(*coeffs)
else:
rep = DMP.from_list(coeffs.to_list(), 0, dom)
scoeffs = Tuple(*coeffs.to_list())
if rep.degree() >= minpoly.degree():
rep = rep.rem(minpoly.rep)
else:
rep = DMP.from_list([1, 0], 0, dom)
scoeffs = Tuple(1, 0)
sargs = (root, scoeffs)
if alias is not None:
if not isinstance(alias, Symbol):
alias = Symbol(alias)
sargs = sargs + (alias,)
obj = Expr.__new__(cls, *sargs)
obj.rep = rep
obj.root = root
obj.alias = alias
obj.minpoly = minpoly
return obj
def __hash__(self):
return super(AlgebraicNumber, self).__hash__()
def _eval_evalf(self, prec):
return self.as_expr()._evalf(prec)
@property
def is_aliased(self):
"""Returns ``True`` if ``alias`` was set. """
return self.alias is not None
def as_poly(self, x=None):
"""Create a Poly instance from ``self``. """
from sympy import Dummy, Poly, PurePoly
if x is not None:
return Poly.new(self.rep, x)
else:
if self.alias is not None:
return Poly.new(self.rep, self.alias)
else:
return PurePoly.new(self.rep, Dummy('x'))
def as_expr(self, x=None):
"""Create a Basic expression from ``self``. """
return self.as_poly(x or self.root).as_expr().expand()
def coeffs(self):
"""Returns all SymPy coefficients of an algebraic number. """
return [ self.rep.dom.to_sympy(c) for c in self.rep.all_coeffs() ]
def native_coeffs(self):
"""Returns all native coefficients of an algebraic number. """
return self.rep.all_coeffs()
def to_algebraic_integer(self):
"""Convert ``self`` to an algebraic integer. """
from sympy import Poly
f = self.minpoly
if f.LC() == 1:
return self
coeff = f.LC()**(f.degree() - 1)
poly = f.compose(Poly(f.gen/f.LC()))
minpoly = poly*coeff
root = f.LC()*self.root
return AlgebraicNumber((minpoly, root), self.coeffs())
def _eval_simplify(self, ratio, measure, rational, inverse):
from sympy.polys import CRootOf, minpoly
for r in [r for r in self.minpoly.all_roots() if r.func != CRootOf]:
if minpoly(self.root - r).is_Symbol:
# use the matching root if it's simpler
if measure(r) < ratio*measure(self.root):
return AlgebraicNumber(r)
return self
class RationalConstant(Rational):
"""
Abstract base class for rationals with specific behaviors
Derived classes must define class attributes p and q and should probably all
be singletons.
"""
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
class IntegerConstant(Integer):
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
class Zero(with_metaclass(Singleton, IntegerConstant)):
"""The number zero.
Zero is a singleton, and can be accessed by ``S.Zero``
Examples
========
>>> from sympy import S, Integer, zoo
>>> Integer(0) is S.Zero
True
>>> 1/S.Zero
zoo
References
==========
.. [1] https://en.wikipedia.org/wiki/Zero
"""
p = 0
q = 1
is_positive = False
is_negative = False
is_zero = True
is_number = True
__slots__ = []
@staticmethod
def __abs__():
return S.Zero
@staticmethod
def __neg__():
return S.Zero
def _eval_power(self, expt):
if expt.is_positive:
return self
if expt.is_negative:
return S.ComplexInfinity
if expt.is_real is False:
return S.NaN
# infinities are already handled with pos and neg
# tests above; now throw away leading numbers on Mul
# exponent
coeff, terms = expt.as_coeff_Mul()
if coeff.is_negative:
return S.ComplexInfinity**terms
if coeff is not S.One: # there is a Number to discard
return self**terms
def _eval_order(self, *symbols):
# Order(0,x) -> 0
return self
def __nonzero__(self):
return False
__bool__ = __nonzero__
def as_coeff_Mul(self, rational=False): # XXX this routine should be deleted
"""Efficiently extract the coefficient of a summation. """
return S.One, self
class One(with_metaclass(Singleton, IntegerConstant)):
"""The number one.
One is a singleton, and can be accessed by ``S.One``.
Examples
========
>>> from sympy import S, Integer
>>> Integer(1) is S.One
True
References
==========
.. [1] https://en.wikipedia.org/wiki/1_%28number%29
"""
is_number = True
p = 1
q = 1
__slots__ = []
@staticmethod
def __abs__():
return S.One
@staticmethod
def __neg__():
return S.NegativeOne
def _eval_power(self, expt):
return self
def _eval_order(self, *symbols):
return
@staticmethod
def factors(limit=None, use_trial=True, use_rho=False, use_pm1=False,
verbose=False, visual=False):
if visual:
return S.One
else:
return {}
class NegativeOne(with_metaclass(Singleton, IntegerConstant)):
"""The number negative one.
NegativeOne is a singleton, and can be accessed by ``S.NegativeOne``.
Examples
========
>>> from sympy import S, Integer
>>> Integer(-1) is S.NegativeOne
True
See Also
========
One
References
==========
.. [1] https://en.wikipedia.org/wiki/%E2%88%921_%28number%29
"""
is_number = True
p = -1
q = 1
__slots__ = []
@staticmethod
def __abs__():
return S.One
@staticmethod
def __neg__():
return S.One
def _eval_power(self, expt):
if expt.is_odd:
return S.NegativeOne
if expt.is_even:
return S.One
if isinstance(expt, Number):
if isinstance(expt, Float):
return Float(-1.0)**expt
if expt is S.NaN:
return S.NaN
if expt is S.Infinity or expt is S.NegativeInfinity:
return S.NaN
if expt is S.Half:
return S.ImaginaryUnit
if isinstance(expt, Rational):
if expt.q == 2:
return S.ImaginaryUnit**Integer(expt.p)
i, r = divmod(expt.p, expt.q)
if i:
return self**i*self**Rational(r, expt.q)
return
class Half(with_metaclass(Singleton, RationalConstant)):
"""The rational number 1/2.
Half is a singleton, and can be accessed by ``S.Half``.
Examples
========
>>> from sympy import S, Rational
>>> Rational(1, 2) is S.Half
True
References
==========
.. [1] https://en.wikipedia.org/wiki/One_half
"""
is_number = True
p = 1
q = 2
__slots__ = []
@staticmethod
def __abs__():
return S.Half
class Infinity(with_metaclass(Singleton, Number)):
r"""Positive infinite quantity.
In real analysis the symbol `\infty` denotes an unbounded
limit: `x\to\infty` means that `x` grows without bound.
Infinity is often used not only to define a limit but as a value
in the affinely extended real number system. Points labeled `+\infty`
and `-\infty` can be added to the topological space of the real numbers,
producing the two-point compactification of the real numbers. Adding
algebraic properties to this gives us the extended real numbers.
Infinity is a singleton, and can be accessed by ``S.Infinity``,
or can be imported as ``oo``.
Examples
========
>>> from sympy import oo, exp, limit, Symbol
>>> 1 + oo
oo
>>> 42/oo
0
>>> x = Symbol('x')
>>> limit(exp(x), x, oo)
oo
See Also
========
NegativeInfinity, NaN
References
==========
.. [1] https://en.wikipedia.org/wiki/Infinity
"""
is_commutative = True
is_positive = True
is_infinite = True
is_number = True
is_prime = False
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\infty"
def _eval_subs(self, old, new):
if self == old:
return new
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number):
if other is S.NegativeInfinity or other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('-inf'):
return S.NaN
else:
return Float('inf')
else:
return S.Infinity
return NotImplemented
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number):
if other is S.Infinity or other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('inf'):
return S.NaN
else:
return Float('inf')
else:
return S.Infinity
return NotImplemented
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number):
if other is S.Zero or other is S.NaN:
return S.NaN
elif other.is_Float:
if other == 0:
return S.NaN
if other > 0:
return Float('inf')
else:
return Float('-inf')
else:
if other > 0:
return S.Infinity
else:
return S.NegativeInfinity
return NotImplemented
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if isinstance(other, Number):
if other is S.Infinity or \
other is S.NegativeInfinity or \
other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('-inf') or \
other == Float('inf'):
return S.NaN
elif other.is_nonnegative:
return Float('inf')
else:
return Float('-inf')
else:
if other >= 0:
return S.Infinity
else:
return S.NegativeInfinity
return NotImplemented
__truediv__ = __div__
def __abs__(self):
return S.Infinity
def __neg__(self):
return S.NegativeInfinity
def _eval_power(self, expt):
"""
``expt`` is symbolic object but not equal to 0 or 1.
================ ======= ==============================
Expression Result Notes
================ ======= ==============================
``oo ** nan`` ``nan``
``oo ** -p`` ``0`` ``p`` is number, ``oo``
================ ======= ==============================
See Also
========
Pow
NaN
NegativeInfinity
"""
from sympy.functions import re
if expt.is_positive:
return S.Infinity
if expt.is_negative:
return S.Zero
if expt is S.NaN:
return S.NaN
if expt is S.ComplexInfinity:
return S.NaN
if expt.is_real is False and expt.is_number:
expt_real = re(expt)
if expt_real.is_positive:
return S.ComplexInfinity
if expt_real.is_negative:
return S.Zero
if expt_real.is_zero:
return S.NaN
return self**expt.evalf()
def _as_mpf_val(self, prec):
return mlib.finf
def _sage_(self):
import sage.all as sage
return sage.oo
def __hash__(self):
return super(Infinity, self).__hash__()
def __eq__(self, other):
return other is S.Infinity
def __ne__(self, other):
return other is not S.Infinity
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
if other.is_real:
return S.false
return Expr.__lt__(self, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
if other.is_real:
if other.is_finite or other is S.NegativeInfinity:
return S.false
elif other.is_nonpositive:
return S.false
elif other.is_infinite and other.is_positive:
return S.true
return Expr.__le__(self, other)
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
if other.is_real:
if other.is_finite or other is S.NegativeInfinity:
return S.true
elif other.is_nonpositive:
return S.true
elif other.is_infinite and other.is_positive:
return S.false
return Expr.__gt__(self, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
if other.is_real:
return S.true
return Expr.__ge__(self, other)
def __mod__(self, other):
return S.NaN
__rmod__ = __mod__
def floor(self):
return self
def ceiling(self):
return self
oo = S.Infinity
class NegativeInfinity(with_metaclass(Singleton, Number)):
"""Negative infinite quantity.
NegativeInfinity is a singleton, and can be accessed
by ``S.NegativeInfinity``.
See Also
========
Infinity
"""
is_commutative = True
is_negative = True
is_infinite = True
is_number = True
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"-\infty"
def _eval_subs(self, old, new):
if self == old:
return new
@_sympifyit('other', NotImplemented)
def __add__(self, other):
if isinstance(other, Number):
if other is S.Infinity or other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('inf'):
return Float('nan')
else:
return Float('-inf')
else:
return S.NegativeInfinity
return NotImplemented
__radd__ = __add__
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
if isinstance(other, Number):
if other is S.NegativeInfinity or other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('-inf'):
return Float('nan')
else:
return Float('-inf')
else:
return S.NegativeInfinity
return NotImplemented
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
if isinstance(other, Number):
if other is S.Zero or other is S.NaN:
return S.NaN
elif other.is_Float:
if other is S.NaN or other.is_zero:
return S.NaN
elif other.is_positive:
return Float('-inf')
else:
return Float('inf')
else:
if other.is_positive:
return S.NegativeInfinity
else:
return S.Infinity
return NotImplemented
__rmul__ = __mul__
@_sympifyit('other', NotImplemented)
def __div__(self, other):
if isinstance(other, Number):
if other is S.Infinity or \
other is S.NegativeInfinity or \
other is S.NaN:
return S.NaN
elif other.is_Float:
if other == Float('-inf') or \
other == Float('inf') or \
other is S.NaN:
return S.NaN
elif other.is_nonnegative:
return Float('-inf')
else:
return Float('inf')
else:
if other >= 0:
return S.NegativeInfinity
else:
return S.Infinity
return NotImplemented
__truediv__ = __div__
def __abs__(self):
return S.Infinity
def __neg__(self):
return S.Infinity
def _eval_power(self, expt):
"""
``expt`` is symbolic object but not equal to 0 or 1.
================ ======= ==============================
Expression Result Notes
================ ======= ==============================
``(-oo) ** nan`` ``nan``
``(-oo) ** oo`` ``nan``
``(-oo) ** -oo`` ``nan``
``(-oo) ** e`` ``oo`` ``e`` is positive even integer
``(-oo) ** o`` ``-oo`` ``o`` is positive odd integer
================ ======= ==============================
See Also
========
Infinity
Pow
NaN
"""
if expt.is_number:
if expt is S.NaN or \
expt is S.Infinity or \
expt is S.NegativeInfinity:
return S.NaN
if isinstance(expt, Integer) and expt.is_positive:
if expt.is_odd:
return S.NegativeInfinity
else:
return S.Infinity
return S.NegativeOne**expt*S.Infinity**expt
def _as_mpf_val(self, prec):
return mlib.fninf
def _sage_(self):
import sage.all as sage
return -(sage.oo)
def __hash__(self):
return super(NegativeInfinity, self).__hash__()
def __eq__(self, other):
return other is S.NegativeInfinity
def __ne__(self, other):
return other is not S.NegativeInfinity
def __lt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s < %s" % (self, other))
if other.is_real:
if other.is_finite or other is S.Infinity:
return S.true
elif other.is_nonnegative:
return S.true
elif other.is_infinite and other.is_negative:
return S.false
return Expr.__lt__(self, other)
def __le__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s <= %s" % (self, other))
if other.is_real:
return S.true
return Expr.__le__(self, other)
def __gt__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s > %s" % (self, other))
if other.is_real:
return S.false
return Expr.__gt__(self, other)
def __ge__(self, other):
try:
other = _sympify(other)
except SympifyError:
raise TypeError("Invalid comparison %s >= %s" % (self, other))
if other.is_real:
if other.is_finite or other is S.Infinity:
return S.false
elif other.is_nonnegative:
return S.false
elif other.is_infinite and other.is_negative:
return S.true
return Expr.__ge__(self, other)
def __mod__(self, other):
return S.NaN
__rmod__ = __mod__
def floor(self):
return self
def ceiling(self):
return self
class NaN(with_metaclass(Singleton, Number)):
"""
Not a Number.
This serves as a place holder for numeric values that are indeterminate.
Most operations on NaN, produce another NaN. Most indeterminate forms,
such as ``0/0`` or ``oo - oo` produce NaN. Two exceptions are ``0**0``
and ``oo**0``, which all produce ``1`` (this is consistent with Python's
float).
NaN is loosely related to floating point nan, which is defined in the
IEEE 754 floating point standard, and corresponds to the Python
``float('nan')``. Differences are noted below.
NaN is mathematically not equal to anything else, even NaN itself. This
explains the initially counter-intuitive results with ``Eq`` and ``==`` in
the examples below.
NaN is not comparable so inequalities raise a TypeError. This is in
constrast with floating point nan where all inequalities are false.
NaN is a singleton, and can be accessed by ``S.NaN``, or can be imported
as ``nan``.
Examples
========
>>> from sympy import nan, S, oo, Eq
>>> nan is S.NaN
True
>>> oo - oo
nan
>>> nan + 1
nan
>>> Eq(nan, nan) # mathematical equality
False
>>> nan == nan # structural equality
True
References
==========
.. [1] https://en.wikipedia.org/wiki/NaN
"""
is_commutative = True
is_real = None
is_rational = None
is_algebraic = None
is_transcendental = None
is_integer = None
is_comparable = False
is_finite = None
is_zero = None
is_prime = None
is_positive = None
is_negative = None
is_number = True
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\mathrm{NaN}"
@_sympifyit('other', NotImplemented)
def __add__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __sub__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __mul__(self, other):
return self
@_sympifyit('other', NotImplemented)
def __div__(self, other):
return self
__truediv__ = __div__
def floor(self):
return self
def ceiling(self):
return self
def _as_mpf_val(self, prec):
return _mpf_nan
def _sage_(self):
import sage.all as sage
return sage.NaN
def __hash__(self):
return super(NaN, self).__hash__()
def __eq__(self, other):
# NaN is structurally equal to another NaN
return other is S.NaN
def __ne__(self, other):
return other is not S.NaN
def _eval_Eq(self, other):
# NaN is not mathematically equal to anything, even NaN
return S.false
# Expr will _sympify and raise TypeError
__gt__ = Expr.__gt__
__ge__ = Expr.__ge__
__lt__ = Expr.__lt__
__le__ = Expr.__le__
nan = S.NaN
class ComplexInfinity(with_metaclass(Singleton, AtomicExpr)):
r"""Complex infinity.
In complex analysis the symbol `\tilde\infty`, called "complex
infinity", represents a quantity with infinite magnitude, but
undetermined complex phase.
ComplexInfinity is a singleton, and can be accessed by
``S.ComplexInfinity``, or can be imported as ``zoo``.
Examples
========
>>> from sympy import zoo, oo
>>> zoo + 42
zoo
>>> 42/zoo
0
>>> zoo + zoo
nan
>>> zoo*zoo
zoo
See Also
========
Infinity
"""
is_commutative = True
is_infinite = True
is_number = True
is_prime = False
is_complex = True
is_real = False
__slots__ = []
def __new__(cls):
return AtomicExpr.__new__(cls)
def _latex(self, printer):
return r"\tilde{\infty}"
@staticmethod
def __abs__():
return S.Infinity
def floor(self):
return self
def ceiling(self):
return self
@staticmethod
def __neg__():
return S.ComplexInfinity
def _eval_power(self, expt):
if expt is S.ComplexInfinity:
return S.NaN
if isinstance(expt, Number):
if expt is S.Zero:
return S.NaN
else:
if expt.is_positive:
return S.ComplexInfinity
else:
return S.Zero
def _sage_(self):
import sage.all as sage
return sage.UnsignedInfinityRing.gen()
zoo = S.ComplexInfinity
class NumberSymbol(AtomicExpr):
is_commutative = True
is_finite = True
is_number = True
__slots__ = []
is_NumberSymbol = True
def __new__(cls):
return AtomicExpr.__new__(cls)
def approximation(self, number_cls):
""" Return an interval with number_cls endpoints
that contains the value of NumberSymbol.
If not implemented, then return None.
"""
def _eval_evalf(self, prec):
return Float._new(self._as_mpf_val(prec), prec)
def __eq__(self, other):
try:
other = _sympify(other)
except SympifyError:
return NotImplemented
if self is other:
return True
if other.is_Number and self.is_irrational:
return False
return False # NumberSymbol != non-(Number|self)
def __ne__(self, other):
return not self == other
def __le__(self, other):
if self is other:
return S.true
return Expr.__le__(self, other)
def __ge__(self, other):
if self is other:
return S.true
return Expr.__ge__(self, other)
def __int__(self):
# subclass with appropriate return value
raise NotImplementedError
def __long__(self):
return self.__int__()
def __hash__(self):
return super(NumberSymbol, self).__hash__()
class Exp1(with_metaclass(Singleton, NumberSymbol)):
r"""The `e` constant.
The transcendental number `e = 2.718281828\ldots` is the base of the
natural logarithm and of the exponential function, `e = \exp(1)`.
Sometimes called Euler's number or Napier's constant.
Exp1 is a singleton, and can be accessed by ``S.Exp1``,
or can be imported as ``E``.
Examples
========
>>> from sympy import exp, log, E
>>> E is exp(1)
True
>>> log(E)
1
References
==========
.. [1] https://en.wikipedia.org/wiki/E_%28mathematical_constant%29
"""
is_real = True
is_positive = True
is_negative = False # XXX Forces is_negative/is_nonnegative
is_irrational = True
is_number = True
is_algebraic = False
is_transcendental = True
__slots__ = []
def _latex(self, printer):
return r"e"
@staticmethod
def __abs__():
return S.Exp1
def __int__(self):
return 2
def _as_mpf_val(self, prec):
return mpf_e(prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (Integer(2), Integer(3))
elif issubclass(number_cls, Rational):
pass
def _eval_power(self, expt):
from sympy import exp
return exp(expt)
def _eval_rewrite_as_sin(self, **kwargs):
from sympy import sin
I = S.ImaginaryUnit
return sin(I + S.Pi/2) - I*sin(I)
def _eval_rewrite_as_cos(self, **kwargs):
from sympy import cos
I = S.ImaginaryUnit
return cos(I) + I*cos(I + S.Pi/2)
def _sage_(self):
import sage.all as sage
return sage.e
E = S.Exp1
class Pi(with_metaclass(Singleton, NumberSymbol)):
r"""The `\pi` constant.
The transcendental number `\pi = 3.141592654\ldots` represents the ratio
of a circle's circumference to its diameter, the area of the unit circle,
the half-period of trigonometric functions, and many other things
in mathematics.
Pi is a singleton, and can be accessed by ``S.Pi``, or can
be imported as ``pi``.
Examples
========
>>> from sympy import S, pi, oo, sin, exp, integrate, Symbol
>>> S.Pi
pi
>>> pi > 3
True
>>> pi.is_irrational
True
>>> x = Symbol('x')
>>> sin(x + 2*pi)
sin(x)
>>> integrate(exp(-x**2), (x, -oo, oo))
sqrt(pi)
References
==========
.. [1] https://en.wikipedia.org/wiki/Pi
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = False
is_transcendental = True
__slots__ = []
def _latex(self, printer):
return r"\pi"
@staticmethod
def __abs__():
return S.Pi
def __int__(self):
return 3
def _as_mpf_val(self, prec):
return mpf_pi(prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (Integer(3), Integer(4))
elif issubclass(number_cls, Rational):
return (Rational(223, 71), Rational(22, 7))
def _sage_(self):
import sage.all as sage
return sage.pi
pi = S.Pi
class GoldenRatio(with_metaclass(Singleton, NumberSymbol)):
r"""The golden ratio, `\phi`.
`\phi = \frac{1 + \sqrt{5}}{2}` is algebraic number. Two quantities
are in the golden ratio if their ratio is the same as the ratio of
their sum to the larger of the two quantities, i.e. their maximum.
GoldenRatio is a singleton, and can be accessed by ``S.GoldenRatio``.
Examples
========
>>> from sympy import S
>>> S.GoldenRatio > 1
True
>>> S.GoldenRatio.expand(func=True)
1/2 + sqrt(5)/2
>>> S.GoldenRatio.is_irrational
True
References
==========
.. [1] https://en.wikipedia.org/wiki/Golden_ratio
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = True
is_transcendental = False
__slots__ = []
def _latex(self, printer):
return r"\phi"
def __int__(self):
return 1
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
rv = mlib.from_man_exp(phi_fixed(prec + 10), -prec - 10)
return mpf_norm(rv, prec)
def _eval_expand_func(self, **hints):
from sympy import sqrt
return S.Half + S.Half*sqrt(5)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.One, Rational(2))
elif issubclass(number_cls, Rational):
pass
def _sage_(self):
import sage.all as sage
return sage.golden_ratio
_eval_rewrite_as_sqrt = _eval_expand_func
class TribonacciConstant(with_metaclass(Singleton, NumberSymbol)):
r"""The tribonacci constant.
The tribonacci numbers are like the Fibonacci numbers, but instead
of starting with two predetermined terms, the sequence starts with
three predetermined terms and each term afterwards is the sum of the
preceding three terms.
The tribonacci constant is the ratio toward which adjacent tribonacci
numbers tend. It is a root of the polynomial `x^3 - x^2 - x - 1 = 0`,
and also satisfies the equation `x + x^{-3} = 2`.
TribonacciConstant is a singleton, and can be accessed
by ``S.TribonacciConstant``.
Examples
========
>>> from sympy import S
>>> S.TribonacciConstant > 1
True
>>> S.TribonacciConstant.expand(func=True)
1/3 + (-3*sqrt(33) + 19)**(1/3)/3 + (3*sqrt(33) + 19)**(1/3)/3
>>> S.TribonacciConstant.is_irrational
True
>>> S.TribonacciConstant.n(20)
1.8392867552141611326
References
==========
.. [1] https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers#Tribonacci_numbers
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = True
is_number = True
is_algebraic = True
is_transcendental = False
__slots__ = []
def _latex(self, printer):
return r"\mathrm{TribonacciConstant}"
def __int__(self):
return 2
def _eval_evalf(self, prec):
rv = self._eval_expand_func(function=True)._eval_evalf(prec + 4)
return Float(rv, precision=prec)
def _eval_expand_func(self, **hints):
from sympy import sqrt, cbrt
return (1 + cbrt(19 - 3*sqrt(33)) + cbrt(19 + 3*sqrt(33))) / 3
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.One, Rational(2))
elif issubclass(number_cls, Rational):
pass
_eval_rewrite_as_sqrt = _eval_expand_func
class EulerGamma(with_metaclass(Singleton, NumberSymbol)):
r"""The Euler-Mascheroni constant.
`\gamma = 0.5772157\ldots` (also called Euler's constant) is a mathematical
constant recurring in analysis and number theory. It is defined as the
limiting difference between the harmonic series and the
natural logarithm:
.. math:: \gamma = \lim\limits_{n\to\infty}
\left(\sum\limits_{k=1}^n\frac{1}{k} - \ln n\right)
EulerGamma is a singleton, and can be accessed by ``S.EulerGamma``.
Examples
========
>>> from sympy import S
>>> S.EulerGamma.is_irrational
>>> S.EulerGamma > 0
True
>>> S.EulerGamma > 1
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Euler%E2%80%93Mascheroni_constant
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = None
is_number = True
__slots__ = []
def _latex(self, printer):
return r"\gamma"
def __int__(self):
return 0
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
v = mlib.libhyper.euler_fixed(prec + 10)
rv = mlib.from_man_exp(v, -prec - 10)
return mpf_norm(rv, prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.Zero, S.One)
elif issubclass(number_cls, Rational):
return (S.Half, Rational(3, 5))
def _sage_(self):
import sage.all as sage
return sage.euler_gamma
class Catalan(with_metaclass(Singleton, NumberSymbol)):
r"""Catalan's constant.
`K = 0.91596559\ldots` is given by the infinite series
.. math:: K = \sum_{k=0}^{\infty} \frac{(-1)^k}{(2k+1)^2}
Catalan is a singleton, and can be accessed by ``S.Catalan``.
Examples
========
>>> from sympy import S
>>> S.Catalan.is_irrational
>>> S.Catalan > 0
True
>>> S.Catalan > 1
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Catalan%27s_constant
"""
is_real = True
is_positive = True
is_negative = False
is_irrational = None
is_number = True
__slots__ = []
def __int__(self):
return 0
def _as_mpf_val(self, prec):
# XXX track down why this has to be increased
v = mlib.catalan_fixed(prec + 10)
rv = mlib.from_man_exp(v, -prec - 10)
return mpf_norm(rv, prec)
def approximation_interval(self, number_cls):
if issubclass(number_cls, Integer):
return (S.Zero, S.One)
elif issubclass(number_cls, Rational):
return (Rational(9, 10), S.One)
def _sage_(self):
import sage.all as sage
return sage.catalan
class ImaginaryUnit(with_metaclass(Singleton, AtomicExpr)):
r"""The imaginary unit, `i = \sqrt{-1}`.
I is a singleton, and can be accessed by ``S.I``, or can be
imported as ``I``.
Examples
========
>>> from sympy import I, sqrt
>>> sqrt(-1)
I
>>> I*I
-1
>>> 1/I
-I
References
==========
.. [1] https://en.wikipedia.org/wiki/Imaginary_unit
"""
is_commutative = True
is_imaginary = True
is_finite = True
is_number = True
is_algebraic = True
is_transcendental = False
__slots__ = []
def _latex(self, printer):
return r"i"
@staticmethod
def __abs__():
return S.One
def _eval_evalf(self, prec):
return self
def _eval_conjugate(self):
return -S.ImaginaryUnit
def _eval_power(self, expt):
"""
b is I = sqrt(-1)
e is symbolic object but not equal to 0, 1
I**r -> (-1)**(r/2) -> exp(r/2*Pi*I) -> sin(Pi*r/2) + cos(Pi*r/2)*I, r is decimal
I**0 mod 4 -> 1
I**1 mod 4 -> I
I**2 mod 4 -> -1
I**3 mod 4 -> -I
"""
if isinstance(expt, Number):
if isinstance(expt, Integer):
expt = expt.p % 4
if expt == 0:
return S.One
if expt == 1:
return S.ImaginaryUnit
if expt == 2:
return -S.One
return -S.ImaginaryUnit
return
def as_base_exp(self):
return S.NegativeOne, S.Half
def _sage_(self):
import sage.all as sage
return sage.I
@property
def _mpc_(self):
return (Float(0)._mpf_, Float(1)._mpf_)
I = S.ImaginaryUnit
def sympify_fractions(f):
return Rational(f.numerator, f.denominator, 1)
converter[fractions.Fraction] = sympify_fractions
try:
if HAS_GMPY == 2:
import gmpy2 as gmpy
elif HAS_GMPY == 1:
import gmpy
else:
raise ImportError
def sympify_mpz(x):
return Integer(long(x))
def sympify_mpq(x):
return Rational(long(x.numerator), long(x.denominator))
converter[type(gmpy.mpz(1))] = sympify_mpz
converter[type(gmpy.mpq(1, 2))] = sympify_mpq
except ImportError:
pass
def sympify_mpmath(x):
return Expr._from_mpmath(x, x.context.prec)
converter[mpnumeric] = sympify_mpmath
def sympify_mpq(x):
p, q = x._mpq_
return Rational(p, q, 1)
converter[type(mpmath.rational.mpq(1, 2))] = sympify_mpq
def sympify_complex(a):
real, imag = list(map(sympify, (a.real, a.imag)))
return real + S.ImaginaryUnit*imag
converter[complex] = sympify_complex
_intcache[0] = S.Zero
_intcache[1] = S.One
_intcache[-1] = S.NegativeOne
from .power import Pow, integer_nthroot
from .mul import Mul
Mul.identity = One()
from .add import Add
Add.identity = Zero()
|
3dd389b661ea06590ddb5ed7717bc6686237fee8b9d24441764ebc76202ac4cc
|
from __future__ import print_function, division
from sympy.core.numbers import nan, Integer
from sympy.core.compatibility import integer_types
from .function import Function
class Mod(Function):
"""Represents a modulo operation on symbolic expressions.
Receives two arguments, dividend p and divisor q.
The convention used is the same as Python's: the remainder always has the
same sign as the divisor.
Examples
========
>>> from sympy.abc import x, y
>>> x**2 % y
Mod(x**2, y)
>>> _.subs({x: 5, y: 6})
1
"""
@classmethod
def eval(cls, p, q):
from sympy.core.add import Add
from sympy.core.mul import Mul
from sympy.core.singleton import S
from sympy.core.exprtools import gcd_terms
from sympy.polys.polytools import gcd
def doit(p, q):
"""Try to return p % q if both are numbers or +/-p is known
to be less than or equal q.
"""
if q == S.Zero:
raise ZeroDivisionError("Modulo by zero")
if p.is_infinite or q.is_infinite or p is nan or q is nan:
return nan
if p == S.Zero or p == q or p == -q or (p.is_integer and q == 1):
return S.Zero
if q.is_Number:
if p.is_Number:
return p%q
if q == 2:
if p.is_even:
return S.Zero
elif p.is_odd:
return S.One
if hasattr(p, '_eval_Mod'):
rv = getattr(p, '_eval_Mod')(q)
if rv is not None:
return rv
# by ratio
r = p/q
try:
d = int(r)
except TypeError:
pass
else:
if isinstance(d, integer_types):
rv = p - d*q
if (rv*q < 0) == True:
rv += q
return rv
# by difference
# -2|q| < p < 2|q|
d = abs(p)
for _ in range(2):
d -= abs(q)
if d.is_negative:
if q.is_positive:
if p.is_positive:
return d + q
elif p.is_negative:
return -d
elif q.is_negative:
if p.is_positive:
return d
elif p.is_negative:
return -d + q
break
rv = doit(p, q)
if rv is not None:
return rv
# denest
if isinstance(p, cls):
qinner = p.args[1]
if qinner % q == 0:
return cls(p.args[0], q)
elif (qinner*(q - qinner)).is_nonnegative:
# |qinner| < |q| and have same sign
return p
elif isinstance(-p, cls):
qinner = (-p).args[1]
if qinner % q == 0:
return cls(-(-p).args[0], q)
elif (qinner*(q + qinner)).is_nonpositive:
# |qinner| < |q| and have different sign
return p
elif isinstance(p, Add):
# separating into modulus and non modulus
both_l = non_mod_l, mod_l = [], []
for arg in p.args:
both_l[isinstance(arg, cls)].append(arg)
# if q same for all
if mod_l and all(inner.args[1] == q for inner in mod_l):
net = Add(*non_mod_l) + Add(*[i.args[0] for i in mod_l])
return cls(net, q)
elif isinstance(p, Mul):
# separating into modulus and non modulus
both_l = non_mod_l, mod_l = [], []
for arg in p.args:
both_l[isinstance(arg, cls)].append(arg)
if mod_l and all(inner.args[1] == q for inner in mod_l):
# finding distributive term
non_mod_l = [cls(x, q) for x in non_mod_l]
mod = []
non_mod = []
for j in non_mod_l:
if isinstance(j, cls):
mod.append(j.args[0])
else:
non_mod.append(j)
prod_mod = Mul(*mod)
prod_non_mod = Mul(*non_mod)
prod_mod1 = Mul(*[i.args[0] for i in mod_l])
net = prod_mod1*prod_mod
return prod_non_mod*cls(net, q)
if q.is_Integer and q is not S.One:
_ = []
for i in non_mod_l:
if i.is_Integer and (i % q is not S.Zero):
_.append(i%q)
else:
_.append(i)
non_mod_l = _
p = Mul(*(non_mod_l + mod_l))
# XXX other possibilities?
# extract gcd; any further simplification should be done by the user
G = gcd(p, q)
if G != 1:
p, q = [
gcd_terms(i/G, clear=False, fraction=False) for i in (p, q)]
pwas, qwas = p, q
# simplify terms
# (x + y + 2) % x -> Mod(y + 2, x)
if p.is_Add:
args = []
for i in p.args:
a = cls(i, q)
if a.count(cls) > i.count(cls):
args.append(i)
else:
args.append(a)
if args != list(p.args):
p = Add(*args)
else:
# handle coefficients if they are not Rational
# since those are not handled by factor_terms
# e.g. Mod(.6*x, .3*y) -> 0.3*Mod(2*x, y)
cp, p = p.as_coeff_Mul()
cq, q = q.as_coeff_Mul()
ok = False
if not cp.is_Rational or not cq.is_Rational:
r = cp % cq
if r == 0:
G *= cq
p *= int(cp/cq)
ok = True
if not ok:
p = cp*p
q = cq*q
# simple -1 extraction
if p.could_extract_minus_sign() and q.could_extract_minus_sign():
G, p, q = [-i for i in (G, p, q)]
# check again to see if p and q can now be handled as numbers
rv = doit(p, q)
if rv is not None:
return rv*G
# put 1.0 from G on inside
if G.is_Float and G == 1:
p *= G
return cls(p, q, evaluate=False)
elif G.is_Mul and G.args[0].is_Float and G.args[0] == 1:
p = G.args[0]*p
G = Mul._from_args(G.args[1:])
return G*cls(p, q, evaluate=(p, q) != (pwas, qwas))
def _eval_is_integer(self):
from sympy.core.logic import fuzzy_and, fuzzy_not
p, q = self.args
if fuzzy_and([p.is_integer, q.is_integer, fuzzy_not(q.is_zero)]):
return True
def _eval_is_nonnegative(self):
if self.args[1].is_positive:
return True
def _eval_is_nonpositive(self):
if self.args[1].is_negative:
return True
|
4e4e4bae4e44df5235f07d0ed86d6460ec8d74416d6b516321450d526867221f
|
"""
Reimplementations of constructs introduced in later versions of Python than
we support. Also some functions that are needed SymPy-wide and are located
here for easy import.
"""
from __future__ import print_function, division
import operator
from collections import defaultdict
from sympy.external import import_module
"""
Python 2 and Python 3 compatible imports
String and Unicode compatible changes:
* `unicode()` removed in Python 3, import `unicode` for Python 2/3
compatible function
* `unichr()` removed in Python 3, import `unichr` for Python 2/3 compatible
function
* Use `u()` for escaped unicode sequences (e.g. u'\u2020' -> u('\u2020'))
* Use `u_decode()` to decode utf-8 formatted unicode strings
* `string_types` gives str in Python 3, unicode and str in Python 2,
equivalent to basestring
Integer related changes:
* `long()` removed in Python 3, import `long` for Python 2/3 compatible
function
* `integer_types` gives int in Python 3, int and long in Python 2
Types related changes:
* `class_types` gives type in Python 3, type and ClassType in Python 2
Renamed function attributes:
* Python 2 `.func_code`, Python 3 `.__func__`, access with
`get_function_code()`
* Python 2 `.func_globals`, Python 3 `.__globals__`, access with
`get_function_globals()`
* Python 2 `.func_name`, Python 3 `.__name__`, access with
`get_function_name()`
Moved modules:
* `reduce()`
* `StringIO()`
* `cStringIO()` (same as `StingIO()` in Python 3)
* Python 2 `__builtins__`, access with Python 3 name, `builtins`
Iterator/list changes:
* `xrange` renamed as `range` in Python 3, import `range` for Python 2/3
compatible iterator version of range.
exec:
* Use `exec_()`, with parameters `exec_(code, globs=None, locs=None)`
Metaclasses:
* Use `with_metaclass()`, examples below
* Define class `Foo` with metaclass `Meta`, and no parent:
class Foo(with_metaclass(Meta)):
pass
* Define class `Foo` with metaclass `Meta` and parent class `Bar`:
class Foo(with_metaclass(Meta, Bar)):
pass
"""
import sys
PY3 = sys.version_info[0] > 2
if PY3:
class_types = type,
integer_types = (int,)
string_types = (str,)
long = int
int_info = sys.int_info
# String / unicode compatibility
unicode = str
unichr = chr
def u_decode(x):
return x
Iterator = object
# Moved definitions
get_function_code = operator.attrgetter("__code__")
get_function_globals = operator.attrgetter("__globals__")
get_function_name = operator.attrgetter("__name__")
import builtins
from functools import reduce
from io import StringIO
cStringIO = StringIO
exec_=getattr(builtins, "exec")
range=range
from collections.abc import (Mapping, Callable, MutableMapping,
MutableSet, Iterable, Hashable)
from inspect import unwrap
from itertools import accumulate
else:
import codecs
import types
class_types = (type, types.ClassType)
integer_types = (int, long)
string_types = (str, unicode)
long = long
int_info = sys.long_info
# String / unicode compatibility
unicode = unicode
unichr = unichr
def u_decode(x):
return x.decode('utf-8')
class Iterator(object):
def next(self):
return type(self).__next__(self)
# Moved definitions
get_function_code = operator.attrgetter("func_code")
get_function_globals = operator.attrgetter("func_globals")
get_function_name = operator.attrgetter("func_name")
import __builtin__ as builtins
reduce = reduce
from StringIO import StringIO
from cStringIO import StringIO as cStringIO
def exec_(_code_, _globs_=None, _locs_=None):
"""Execute code in a namespace."""
if _globs_ is None:
frame = sys._getframe(1)
_globs_ = frame.f_globals
if _locs_ is None:
_locs_ = frame.f_locals
del frame
elif _locs_ is None:
_locs_ = _globs_
exec("exec _code_ in _globs_, _locs_")
range=xrange
from collections import (Mapping, Callable, MutableMapping,
MutableSet, Iterable, Hashable)
def unwrap(func, stop=None):
"""Get the object wrapped by *func*.
Follows the chain of :attr:`__wrapped__` attributes returning the last
object in the chain.
*stop* is an optional callback accepting an object in the wrapper chain
as its sole argument that allows the unwrapping to be terminated early if
the callback returns a true value. If the callback never returns a true
value, the last object in the chain is returned as usual. For example,
:func:`signature` uses this to stop unwrapping if any object in the
chain has a ``__signature__`` attribute defined.
:exc:`ValueError` is raised if a cycle is encountered.
"""
if stop is None:
def _is_wrapper(f):
return hasattr(f, '__wrapped__')
else:
def _is_wrapper(f):
return hasattr(f, '__wrapped__') and not stop(f)
f = func # remember the original func for error reporting
memo = {id(f)} # Memoise by id to tolerate non-hashable objects
while _is_wrapper(func):
func = func.__wrapped__
id_func = id(func)
if id_func in memo:
raise ValueError('wrapper loop when unwrapping {!r}'.format(f))
memo.add(id_func)
return func
def accumulate(iterable, func=operator.add):
state = iterable[0]
yield state
for i in iterable[1:]:
state = func(state, i)
yield state
def with_metaclass(meta, *bases):
"""
Create a base class with a metaclass.
For example, if you have the metaclass
>>> class Meta(type):
... pass
Use this as the metaclass by doing
>>> from sympy.core.compatibility import with_metaclass
>>> class MyClass(with_metaclass(Meta, object)):
... pass
This is equivalent to the Python 2::
class MyClass(object):
__metaclass__ = Meta
or Python 3::
class MyClass(object, metaclass=Meta):
pass
That is, the first argument is the metaclass, and the remaining arguments
are the base classes. Note that if the base class is just ``object``, you
may omit it.
>>> MyClass.__mro__
(<class '...MyClass'>, <... 'object'>)
>>> type(MyClass)
<class '...Meta'>
"""
# This requires a bit of explanation: the basic idea is to make a dummy
# metaclass for one level of class instantiation that replaces itself with
# the actual metaclass.
# Code copied from the 'six' library.
class metaclass(meta):
def __new__(cls, name, this_bases, d):
return meta(name, bases, d)
return type.__new__(metaclass, "NewBase", (), {})
# These are in here because telling if something is an iterable just by calling
# hasattr(obj, "__iter__") behaves differently in Python 2 and Python 3. In
# particular, hasattr(str, "__iter__") is False in Python 2 and True in Python 3.
# I think putting them here also makes it easier to use them in the core.
class NotIterable:
"""
Use this as mixin when creating a class which is not supposed to return
true when iterable() is called on its instances. I.e. avoid infinite loop
when calling e.g. list() on the instance
"""
pass
def iterable(i, exclude=(string_types, dict, NotIterable)):
"""
Return a boolean indicating whether ``i`` is SymPy iterable.
True also indicates that the iterator is finite, i.e. you e.g.
call list(...) on the instance.
When SymPy is working with iterables, it is almost always assuming
that the iterable is not a string or a mapping, so those are excluded
by default. If you want a pure Python definition, make exclude=None. To
exclude multiple items, pass them as a tuple.
You can also set the _iterable attribute to True or False on your class,
which will override the checks here, including the exclude test.
As a rule of thumb, some SymPy functions use this to check if they should
recursively map over an object. If an object is technically iterable in
the Python sense but does not desire this behavior (e.g., because its
iteration is not finite, or because iteration might induce an unwanted
computation), it should disable it by setting the _iterable attribute to False.
See also: is_sequence
Examples
========
>>> from sympy.utilities.iterables import iterable
>>> from sympy import Tuple
>>> things = [[1], (1,), set([1]), Tuple(1), (j for j in [1, 2]), {1:2}, '1', 1]
>>> for i in things:
... print('%s %s' % (iterable(i), type(i)))
True <... 'list'>
True <... 'tuple'>
True <... 'set'>
True <class 'sympy.core.containers.Tuple'>
True <... 'generator'>
False <... 'dict'>
False <... 'str'>
False <... 'int'>
>>> iterable({}, exclude=None)
True
>>> iterable({}, exclude=str)
True
>>> iterable("no", exclude=str)
False
"""
if hasattr(i, '_iterable'):
return i._iterable
try:
iter(i)
except TypeError:
return False
if exclude:
return not isinstance(i, exclude)
return True
def is_sequence(i, include=None):
"""
Return a boolean indicating whether ``i`` is a sequence in the SymPy
sense. If anything that fails the test below should be included as
being a sequence for your application, set 'include' to that object's
type; multiple types should be passed as a tuple of types.
Note: although generators can generate a sequence, they often need special
handling to make sure their elements are captured before the generator is
exhausted, so these are not included by default in the definition of a
sequence.
See also: iterable
Examples
========
>>> from sympy.utilities.iterables import is_sequence
>>> from types import GeneratorType
>>> is_sequence([])
True
>>> is_sequence(set())
False
>>> is_sequence('abc')
False
>>> is_sequence('abc', include=str)
True
>>> generator = (c for c in 'abc')
>>> is_sequence(generator)
False
>>> is_sequence(generator, include=(str, GeneratorType))
True
"""
return (hasattr(i, '__getitem__') and
iterable(i) or
bool(include) and
isinstance(i, include))
try:
from itertools import zip_longest
except ImportError: # Python 2.7
from itertools import izip_longest as zip_longest
try:
# Python 2.7
from string import maketrans
except ImportError:
maketrans = str.maketrans
def as_int(n):
"""
Convert the argument to a builtin integer.
The return value is guaranteed to be equal to the input. ValueError is
raised if the input has a non-integral value.
Examples
========
>>> from sympy.core.compatibility import as_int
>>> from sympy import sqrt
>>> 3.0
3.0
>>> as_int(3.0) # convert to int and test for equality
3
>>> int(sqrt(10))
3
>>> as_int(sqrt(10))
Traceback (most recent call last):
...
ValueError: ... is not an integer
"""
try:
result = int(n)
if result != n:
raise TypeError
except TypeError:
raise ValueError('%s is not an integer' % (n,))
return result
def default_sort_key(item, order=None):
"""Return a key that can be used for sorting.
The key has the structure:
(class_key, (len(args), args), exponent.sort_key(), coefficient)
This key is supplied by the sort_key routine of Basic objects when
``item`` is a Basic object or an object (other than a string) that
sympifies to a Basic object. Otherwise, this function produces the
key.
The ``order`` argument is passed along to the sort_key routine and is
used to determine how the terms *within* an expression are ordered.
(See examples below) ``order`` options are: 'lex', 'grlex', 'grevlex',
and reversed values of the same (e.g. 'rev-lex'). The default order
value is None (which translates to 'lex').
Examples
========
>>> from sympy import S, I, default_sort_key, sin, cos, sqrt
>>> from sympy.core.function import UndefinedFunction
>>> from sympy.abc import x
The following are equivalent ways of getting the key for an object:
>>> x.sort_key() == default_sort_key(x)
True
Here are some examples of the key that is produced:
>>> default_sort_key(UndefinedFunction('f'))
((0, 0, 'UndefinedFunction'), (1, ('f',)), ((1, 0, 'Number'),
(0, ()), (), 1), 1)
>>> default_sort_key('1')
((0, 0, 'str'), (1, ('1',)), ((1, 0, 'Number'), (0, ()), (), 1), 1)
>>> default_sort_key(S.One)
((1, 0, 'Number'), (0, ()), (), 1)
>>> default_sort_key(2)
((1, 0, 'Number'), (0, ()), (), 2)
While sort_key is a method only defined for SymPy objects,
default_sort_key will accept anything as an argument so it is
more robust as a sorting key. For the following, using key=
lambda i: i.sort_key() would fail because 2 doesn't have a sort_key
method; that's why default_sort_key is used. Note, that it also
handles sympification of non-string items likes ints:
>>> a = [2, I, -I]
>>> sorted(a, key=default_sort_key)
[2, -I, I]
The returned key can be used anywhere that a key can be specified for
a function, e.g. sort, min, max, etc...:
>>> a.sort(key=default_sort_key); a[0]
2
>>> min(a, key=default_sort_key)
2
Note
----
The key returned is useful for getting items into a canonical order
that will be the same across platforms. It is not directly useful for
sorting lists of expressions:
>>> a, b = x, 1/x
Since ``a`` has only 1 term, its value of sort_key is unaffected by
``order``:
>>> a.sort_key() == a.sort_key('rev-lex')
True
If ``a`` and ``b`` are combined then the key will differ because there
are terms that can be ordered:
>>> eq = a + b
>>> eq.sort_key() == eq.sort_key('rev-lex')
False
>>> eq.as_ordered_terms()
[x, 1/x]
>>> eq.as_ordered_terms('rev-lex')
[1/x, x]
But since the keys for each of these terms are independent of ``order``'s
value, they don't sort differently when they appear separately in a list:
>>> sorted(eq.args, key=default_sort_key)
[1/x, x]
>>> sorted(eq.args, key=lambda i: default_sort_key(i, order='rev-lex'))
[1/x, x]
The order of terms obtained when using these keys is the order that would
be obtained if those terms were *factors* in a product.
Although it is useful for quickly putting expressions in canonical order,
it does not sort expressions based on their complexity defined by the
number of operations, power of variables and others:
>>> sorted([sin(x)*cos(x), sin(x)], key=default_sort_key)
[sin(x)*cos(x), sin(x)]
>>> sorted([x, x**2, sqrt(x), x**3], key=default_sort_key)
[sqrt(x), x, x**2, x**3]
See Also
========
ordered, sympy.core.expr.as_ordered_factors, sympy.core.expr.as_ordered_terms
"""
from .singleton import S
from .basic import Basic
from .sympify import sympify, SympifyError
from .compatibility import iterable
if isinstance(item, Basic):
return item.sort_key(order=order)
if iterable(item, exclude=string_types):
if isinstance(item, dict):
args = item.items()
unordered = True
elif isinstance(item, set):
args = item
unordered = True
else:
# e.g. tuple, list
args = list(item)
unordered = False
args = [default_sort_key(arg, order=order) for arg in args]
if unordered:
# e.g. dict, set
args = sorted(args)
cls_index, args = 10, (len(args), tuple(args))
else:
if not isinstance(item, string_types):
try:
item = sympify(item)
except SympifyError:
# e.g. lambda x: x
pass
else:
if isinstance(item, Basic):
# e.g int -> Integer
return default_sort_key(item)
# e.g. UndefinedFunction
# e.g. str
cls_index, args = 0, (1, (str(item),))
return (cls_index, 0, item.__class__.__name__
), args, S.One.sort_key(), S.One
def _nodes(e):
"""
A helper for ordered() which returns the node count of ``e`` which
for Basic objects is the number of Basic nodes in the expression tree
but for other objects is 1 (unless the object is an iterable or dict
for which the sum of nodes is returned).
"""
from .basic import Basic
if isinstance(e, Basic):
return e.count(Basic)
elif iterable(e):
return 1 + sum(_nodes(ei) for ei in e)
elif isinstance(e, dict):
return 1 + sum(_nodes(k) + _nodes(v) for k, v in e.items())
else:
return 1
def ordered(seq, keys=None, default=True, warn=False):
"""Return an iterator of the seq where keys are used to break ties in
a conservative fashion: if, after applying a key, there are no ties
then no other keys will be computed.
Two default keys will be applied if 1) keys are not provided or 2) the
given keys don't resolve all ties (but only if `default` is True). The
two keys are `_nodes` (which places smaller expressions before large) and
`default_sort_key` which (if the `sort_key` for an object is defined
properly) should resolve any ties.
If ``warn`` is True then an error will be raised if there were no
keys remaining to break ties. This can be used if it was expected that
there should be no ties between items that are not identical.
Examples
========
>>> from sympy.utilities.iterables import ordered
>>> from sympy import count_ops
>>> from sympy.abc import x, y
The count_ops is not sufficient to break ties in this list and the first
two items appear in their original order (i.e. the sorting is stable):
>>> list(ordered([y + 2, x + 2, x**2 + y + 3],
... count_ops, default=False, warn=False))
...
[y + 2, x + 2, x**2 + y + 3]
The default_sort_key allows the tie to be broken:
>>> list(ordered([y + 2, x + 2, x**2 + y + 3]))
...
[x + 2, y + 2, x**2 + y + 3]
Here, sequences are sorted by length, then sum:
>>> seq, keys = [[[1, 2, 1], [0, 3, 1], [1, 1, 3], [2], [1]], [
... lambda x: len(x),
... lambda x: sum(x)]]
...
>>> list(ordered(seq, keys, default=False, warn=False))
[[1], [2], [1, 2, 1], [0, 3, 1], [1, 1, 3]]
If ``warn`` is True, an error will be raised if there were not
enough keys to break ties:
>>> list(ordered(seq, keys, default=False, warn=True))
Traceback (most recent call last):
...
ValueError: not enough keys to break ties
Notes
=====
The decorated sort is one of the fastest ways to sort a sequence for
which special item comparison is desired: the sequence is decorated,
sorted on the basis of the decoration (e.g. making all letters lower
case) and then undecorated. If one wants to break ties for items that
have the same decorated value, a second key can be used. But if the
second key is expensive to compute then it is inefficient to decorate
all items with both keys: only those items having identical first key
values need to be decorated. This function applies keys successively
only when needed to break ties. By yielding an iterator, use of the
tie-breaker is delayed as long as possible.
This function is best used in cases when use of the first key is
expected to be a good hashing function; if there are no unique hashes
from application of a key then that key should not have been used. The
exception, however, is that even if there are many collisions, if the
first group is small and one does not need to process all items in the
list then time will not be wasted sorting what one was not interested
in. For example, if one were looking for the minimum in a list and
there were several criteria used to define the sort order, then this
function would be good at returning that quickly if the first group
of candidates is small relative to the number of items being processed.
"""
d = defaultdict(list)
if keys:
if not isinstance(keys, (list, tuple)):
keys = [keys]
keys = list(keys)
f = keys.pop(0)
for a in seq:
d[f(a)].append(a)
else:
if not default:
raise ValueError('if default=False then keys must be provided')
d[None].extend(seq)
for k in sorted(d.keys()):
if len(d[k]) > 1:
if keys:
d[k] = ordered(d[k], keys, default, warn)
elif default:
d[k] = ordered(d[k], (_nodes, default_sort_key,),
default=False, warn=warn)
elif warn:
from sympy.utilities.iterables import uniq
u = list(uniq(d[k]))
if len(u) > 1:
raise ValueError(
'not enough keys to break ties: %s' % u)
for v in d[k]:
yield v
d.pop(k)
# If HAS_GMPY is 0, no supported version of gmpy is available. Otherwise,
# HAS_GMPY contains the major version number of gmpy; i.e. 1 for gmpy, and
# 2 for gmpy2.
# Versions of gmpy prior to 1.03 do not work correctly with int(largempz)
# For example, int(gmpy.mpz(2**256)) would raise OverflowError.
# See issue 4980.
# Minimum version of gmpy changed to 1.13 to allow a single code base to also
# work with gmpy2.
def _getenv(key, default=None):
from os import getenv
return getenv(key, default)
GROUND_TYPES = _getenv('SYMPY_GROUND_TYPES', 'auto').lower()
HAS_GMPY = 0
if GROUND_TYPES != 'python':
# Don't try to import gmpy2 if ground types is set to gmpy1. This is
# primarily intended for testing.
if GROUND_TYPES != 'gmpy1':
gmpy = import_module('gmpy2', min_module_version='2.0.0',
module_version_attr='version', module_version_attr_call_args=())
if gmpy:
HAS_GMPY = 2
else:
GROUND_TYPES = 'gmpy'
if not HAS_GMPY:
gmpy = import_module('gmpy', min_module_version='1.13',
module_version_attr='version', module_version_attr_call_args=())
if gmpy:
HAS_GMPY = 1
if GROUND_TYPES == 'auto':
if HAS_GMPY:
GROUND_TYPES = 'gmpy'
else:
GROUND_TYPES = 'python'
if GROUND_TYPES == 'gmpy' and not HAS_GMPY:
from warnings import warn
warn("gmpy library is not installed, switching to 'python' ground types")
GROUND_TYPES = 'python'
# SYMPY_INTS is a tuple containing the base types for valid integer types.
SYMPY_INTS = integer_types
if GROUND_TYPES == 'gmpy':
SYMPY_INTS += (type(gmpy.mpz(0)),)
# lru_cache compatible with py2.7 copied directly from
# https://code.activestate.com/
# recipes/578078-py26-and-py30-backport-of-python-33s-lru-cache/
from collections import namedtuple
from functools import update_wrapper
from threading import RLock
_CacheInfo = namedtuple("CacheInfo", ["hits", "misses", "maxsize", "currsize"])
class _HashedSeq(list):
__slots__ = 'hashvalue'
def __init__(self, tup, hash=hash):
self[:] = tup
self.hashvalue = hash(tup)
def __hash__(self):
return self.hashvalue
def _make_key(args, kwds, typed,
kwd_mark = (object(),),
fasttypes = set((int, str, frozenset, type(None))),
sorted=sorted, tuple=tuple, type=type, len=len):
'Make a cache key from optionally typed positional and keyword arguments'
key = args
if kwds:
sorted_items = sorted(kwds.items())
key += kwd_mark
for item in sorted_items:
key += item
if typed:
key += tuple(type(v) for v in args)
if kwds:
key += tuple(type(v) for k, v in sorted_items)
elif len(key) == 1 and type(key[0]) in fasttypes:
return key[0]
return _HashedSeq(key)
def lru_cache(maxsize=100, typed=False):
"""Least-recently-used cache decorator.
If *maxsize* is set to None, the LRU features are disabled and the cache
can grow without bound.
If *typed* is True, arguments of different types will be cached separately.
For example, f(3.0) and f(3) will be treated as distinct calls with
distinct results.
Arguments to the cached function must be hashable.
View the cache statistics named tuple (hits, misses, maxsize, currsize) with
f.cache_info(). Clear the cache and statistics with f.cache_clear().
Access the underlying function with f.__wrapped__.
See: https://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used
"""
# Users should only access the lru_cache through its public API:
# cache_info, cache_clear, and f.__wrapped__
# The internals of the lru_cache are encapsulated for thread safety and
# to allow the implementation to change (including a possible C version).
def decorating_function(user_function):
cache = dict()
stats = [0, 0] # make statistics updateable non-locally
HITS, MISSES = 0, 1 # names for the stats fields
make_key = _make_key
cache_get = cache.get # bound method to lookup key or return None
_len = len # localize the global len() function
lock = RLock() # because linkedlist updates aren't threadsafe
root = [] # root of the circular doubly linked list
root[:] = [root, root, None, None] # initialize by pointing to self
nonlocal_root = [root] # make updateable non-locally
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields
if maxsize == 0:
def wrapper(*args, **kwds):
# no caching, just do a statistics update after a successful call
result = user_function(*args, **kwds)
stats[MISSES] += 1
return result
elif maxsize is None:
def wrapper(*args, **kwds):
# simple caching without ordering or size limit
key = make_key(args, kwds, typed)
result = cache_get(key, root) # root used here as a unique not-found sentinel
if result is not root:
stats[HITS] += 1
return result
result = user_function(*args, **kwds)
cache[key] = result
stats[MISSES] += 1
return result
else:
def wrapper(*args, **kwds):
# size limited caching that tracks accesses by recency
try:
key = make_key(args, kwds, typed) if kwds or typed else args
except TypeError:
stats[MISSES] += 1
return user_function(*args, **kwds)
with lock:
link = cache_get(key)
if link is not None:
# record recent use of the key by moving it to the front of the list
root, = nonlocal_root
link_prev, link_next, key, result = link
link_prev[NEXT] = link_next
link_next[PREV] = link_prev
last = root[PREV]
last[NEXT] = root[PREV] = link
link[PREV] = last
link[NEXT] = root
stats[HITS] += 1
return result
result = user_function(*args, **kwds)
with lock:
root, = nonlocal_root
if key in cache:
# getting here means that this same key was added to the
# cache while the lock was released. since the link
# update is already done, we need only return the
# computed result and update the count of misses.
pass
elif _len(cache) >= maxsize:
# use the old root to store the new key and result
oldroot = root
oldroot[KEY] = key
oldroot[RESULT] = result
# empty the oldest link and make it the new root
root = nonlocal_root[0] = oldroot[NEXT]
oldkey = root[KEY]
oldvalue = root[RESULT]
root[KEY] = root[RESULT] = None
# now update the cache dictionary for the new links
del cache[oldkey]
cache[key] = oldroot
else:
# put result in a new link at the front of the list
last = root[PREV]
link = [last, root, key, result]
last[NEXT] = root[PREV] = cache[key] = link
stats[MISSES] += 1
return result
def cache_info():
"""Report cache statistics"""
with lock:
return _CacheInfo(stats[HITS], stats[MISSES], maxsize, len(cache))
def cache_clear():
"""Clear the cache and cache statistics"""
with lock:
cache.clear()
root = nonlocal_root[0]
root[:] = [root, root, None, None]
stats[:] = [0, 0]
wrapper.__wrapped__ = user_function
wrapper.cache_info = cache_info
wrapper.cache_clear = cache_clear
return update_wrapper(wrapper, user_function)
return decorating_function
### End of backported lru_cache
if sys.version_info[:2] >= (3, 3):
# 3.2 has an lru_cache with an incompatible API
from functools import lru_cache
try:
from itertools import filterfalse
except ImportError: # Python 2.7
def filterfalse(pred, itr):
return filter(lambda x: not pred(x), itr)
|
25a8c8035f0ab61d8a63064e6b5042bfba03550ed6bc2e9f980d0979c379daee
|
from __future__ import print_function, division
from collections import defaultdict
from functools import cmp_to_key
import operator
from .sympify import sympify
from .basic import Basic
from .singleton import S
from .operations import AssocOp
from .cache import cacheit
from .logic import fuzzy_not, _fuzzy_group
from .compatibility import reduce, range
from .expr import Expr
from .evaluate import global_distribute
# internal marker to indicate:
# "there are still non-commutative objects -- don't forget to process them"
class NC_Marker:
is_Order = False
is_Mul = False
is_Number = False
is_Poly = False
is_commutative = False
# Key for sorting commutative args in canonical order
_args_sortkey = cmp_to_key(Basic.compare)
def _mulsort(args):
# in-place sorting of args
args.sort(key=_args_sortkey)
def _unevaluated_Mul(*args):
"""Return a well-formed unevaluated Mul: Numbers are collected and
put in slot 0, any arguments that are Muls will be flattened, and args
are sorted. Use this when args have changed but you still want to return
an unevaluated Mul.
Examples
========
>>> from sympy.core.mul import _unevaluated_Mul as uMul
>>> from sympy import S, sqrt, Mul
>>> from sympy.abc import x
>>> a = uMul(*[S(3.0), x, S(2)])
>>> a.args[0]
6.00000000000000
>>> a.args[1]
x
Two unevaluated Muls with the same arguments will
always compare as equal during testing:
>>> m = uMul(sqrt(2), sqrt(3))
>>> m == uMul(sqrt(3), sqrt(2))
True
>>> u = Mul(sqrt(3), sqrt(2), evaluate=False)
>>> m == uMul(u)
True
>>> m == Mul(*m.args)
False
"""
args = list(args)
newargs = []
ncargs = []
co = S.One
while args:
a = args.pop()
if a.is_Mul:
c, nc = a.args_cnc()
args.extend(c)
if nc:
ncargs.append(Mul._from_args(nc))
elif a.is_Number:
co *= a
else:
newargs.append(a)
_mulsort(newargs)
if co is not S.One:
newargs.insert(0, co)
if ncargs:
newargs.append(Mul._from_args(ncargs))
return Mul._from_args(newargs)
class Mul(Expr, AssocOp):
__slots__ = []
is_Mul = True
@classmethod
def flatten(cls, seq):
"""Return commutative, noncommutative and order arguments by
combining related terms.
Notes
=====
* In an expression like ``a*b*c``, python process this through sympy
as ``Mul(Mul(a, b), c)``. This can have undesirable consequences.
- Sometimes terms are not combined as one would like:
{c.f. https://github.com/sympy/sympy/issues/4596}
>>> from sympy import Mul, sqrt
>>> from sympy.abc import x, y, z
>>> 2*(x + 1) # this is the 2-arg Mul behavior
2*x + 2
>>> y*(x + 1)*2
2*y*(x + 1)
>>> 2*(x + 1)*y # 2-arg result will be obtained first
y*(2*x + 2)
>>> Mul(2, x + 1, y) # all 3 args simultaneously processed
2*y*(x + 1)
>>> 2*((x + 1)*y) # parentheses can control this behavior
2*y*(x + 1)
Powers with compound bases may not find a single base to
combine with unless all arguments are processed at once.
Post-processing may be necessary in such cases.
{c.f. https://github.com/sympy/sympy/issues/5728}
>>> a = sqrt(x*sqrt(y))
>>> a**3
(x*sqrt(y))**(3/2)
>>> Mul(a,a,a)
(x*sqrt(y))**(3/2)
>>> a*a*a
x*sqrt(y)*sqrt(x*sqrt(y))
>>> _.subs(a.base, z).subs(z, a.base)
(x*sqrt(y))**(3/2)
- If more than two terms are being multiplied then all the
previous terms will be re-processed for each new argument.
So if each of ``a``, ``b`` and ``c`` were :class:`Mul`
expression, then ``a*b*c`` (or building up the product
with ``*=``) will process all the arguments of ``a`` and
``b`` twice: once when ``a*b`` is computed and again when
``c`` is multiplied.
Using ``Mul(a, b, c)`` will process all arguments once.
* The results of Mul are cached according to arguments, so flatten
will only be called once for ``Mul(a, b, c)``. If you can
structure a calculation so the arguments are most likely to be
repeats then this can save time in computing the answer. For
example, say you had a Mul, M, that you wished to divide by ``d[i]``
and multiply by ``n[i]`` and you suspect there are many repeats
in ``n``. It would be better to compute ``M*n[i]/d[i]`` rather
than ``M/d[i]*n[i]`` since every time n[i] is a repeat, the
product, ``M*n[i]`` will be returned without flattening -- the
cached value will be returned. If you divide by the ``d[i]``
first (and those are more unique than the ``n[i]``) then that will
create a new Mul, ``M/d[i]`` the args of which will be traversed
again when it is multiplied by ``n[i]``.
{c.f. https://github.com/sympy/sympy/issues/5706}
This consideration is moot if the cache is turned off.
NB
--
The validity of the above notes depends on the implementation
details of Mul and flatten which may change at any time. Therefore,
you should only consider them when your code is highly performance
sensitive.
Removal of 1 from the sequence is already handled by AssocOp.__new__.
"""
from sympy.calculus.util import AccumBounds
from sympy.matrices.expressions import MatrixExpr
rv = None
if len(seq) == 2:
a, b = seq
if b.is_Rational:
a, b = b, a
seq = [a, b]
assert not a is S.One
if not a.is_zero and a.is_Rational:
r, b = b.as_coeff_Mul()
if b.is_Add:
if r is not S.One: # 2-arg hack
# leave the Mul as a Mul
rv = [cls(a*r, b, evaluate=False)], [], None
elif global_distribute[0] and b.is_commutative:
r, b = b.as_coeff_Add()
bargs = [_keep_coeff(a, bi) for bi in Add.make_args(b)]
_addsort(bargs)
ar = a*r
if ar:
bargs.insert(0, ar)
bargs = [Add._from_args(bargs)]
rv = bargs, [], None
if rv:
return rv
# apply associativity, separate commutative part of seq
c_part = [] # out: commutative factors
nc_part = [] # out: non-commutative factors
nc_seq = []
coeff = S.One # standalone term
# e.g. 3 * ...
c_powers = [] # (base,exp) n
# e.g. (x,n) for x
num_exp = [] # (num-base, exp) y
# e.g. (3, y) for ... * 3 * ...
neg1e = S.Zero # exponent on -1 extracted from Number-based Pow and I
pnum_rat = {} # (num-base, Rat-exp) 1/2
# e.g. (3, 1/2) for ... * 3 * ...
order_symbols = None
# --- PART 1 ---
#
# "collect powers and coeff":
#
# o coeff
# o c_powers
# o num_exp
# o neg1e
# o pnum_rat
#
# NOTE: this is optimized for all-objects-are-commutative case
for o in seq:
# O(x)
if o.is_Order:
o, order_symbols = o.as_expr_variables(order_symbols)
# Mul([...])
if o.is_Mul:
if o.is_commutative:
seq.extend(o.args) # XXX zerocopy?
else:
# NCMul can have commutative parts as well
for q in o.args:
if q.is_commutative:
seq.append(q)
else:
nc_seq.append(q)
# append non-commutative marker, so we don't forget to
# process scheduled non-commutative objects
seq.append(NC_Marker)
continue
# 3
elif o.is_Number:
if o is S.NaN or coeff is S.ComplexInfinity and o is S.Zero:
# we know for sure the result will be nan
return [S.NaN], [], None
elif coeff.is_Number or isinstance(coeff, AccumBounds): # it could be zoo
coeff *= o
if coeff is S.NaN:
# we know for sure the result will be nan
return [S.NaN], [], None
continue
elif isinstance(o, AccumBounds):
coeff = o.__mul__(coeff)
continue
elif isinstance(o, MatrixExpr):
if isinstance(coeff, MatrixExpr):
coeff *= o
else:
coeff = o.__mul__(coeff)
continue
elif o is S.ComplexInfinity:
if not coeff:
# 0 * zoo = NaN
return [S.NaN], [], None
if coeff is S.ComplexInfinity:
# zoo * zoo = zoo
return [S.ComplexInfinity], [], None
coeff = S.ComplexInfinity
continue
elif o is S.ImaginaryUnit:
neg1e += S.Half
continue
elif o.is_commutative:
# e
# o = b
b, e = o.as_base_exp()
# y
# 3
if o.is_Pow:
if b.is_Number:
# get all the factors with numeric base so they can be
# combined below, but don't combine negatives unless
# the exponent is an integer
if e.is_Rational:
if e.is_Integer:
coeff *= Pow(b, e) # it is an unevaluated power
continue
elif e.is_negative: # also a sign of an unevaluated power
seq.append(Pow(b, e))
continue
elif b.is_negative:
neg1e += e
b = -b
if b is not S.One:
pnum_rat.setdefault(b, []).append(e)
continue
elif b.is_positive or e.is_integer:
num_exp.append((b, e))
continue
c_powers.append((b, e))
# NON-COMMUTATIVE
# TODO: Make non-commutative exponents not combine automatically
else:
if o is not NC_Marker:
nc_seq.append(o)
# process nc_seq (if any)
while nc_seq:
o = nc_seq.pop(0)
if not nc_part:
nc_part.append(o)
continue
# b c b+c
# try to combine last terms: a * a -> a
o1 = nc_part.pop()
b1, e1 = o1.as_base_exp()
b2, e2 = o.as_base_exp()
new_exp = e1 + e2
# Only allow powers to combine if the new exponent is
# not an Add. This allow things like a**2*b**3 == a**5
# if a.is_commutative == False, but prohibits
# a**x*a**y and x**a*x**b from combining (x,y commute).
if b1 == b2 and (not new_exp.is_Add):
o12 = b1 ** new_exp
# now o12 could be a commutative object
if o12.is_commutative:
seq.append(o12)
continue
else:
nc_seq.insert(0, o12)
else:
nc_part.append(o1)
nc_part.append(o)
# We do want a combined exponent if it would not be an Add, such as
# y 2y 3y
# x * x -> x
# We determine if two exponents have the same term by using
# as_coeff_Mul.
#
# Unfortunately, this isn't smart enough to consider combining into
# exponents that might already be adds, so things like:
# z - y y
# x * x will be left alone. This is because checking every possible
# combination can slow things down.
# gather exponents of common bases...
def _gather(c_powers):
common_b = {} # b:e
for b, e in c_powers:
co = e.as_coeff_Mul()
common_b.setdefault(b, {}).setdefault(
co[1], []).append(co[0])
for b, d in common_b.items():
for di, li in d.items():
d[di] = Add(*li)
new_c_powers = []
for b, e in common_b.items():
new_c_powers.extend([(b, c*t) for t, c in e.items()])
return new_c_powers
# in c_powers
c_powers = _gather(c_powers)
# and in num_exp
num_exp = _gather(num_exp)
# --- PART 2 ---
#
# o process collected powers (x**0 -> 1; x**1 -> x; otherwise Pow)
# o combine collected powers (2**x * 3**x -> 6**x)
# with numeric base
# ................................
# now we have:
# - coeff:
# - c_powers: (b, e)
# - num_exp: (2, e)
# - pnum_rat: {(1/3, [1/3, 2/3, 1/4])}
# 0 1
# x -> 1 x -> x
# this should only need to run twice; if it fails because
# it needs to be run more times, perhaps this should be
# changed to a "while True" loop -- the only reason it
# isn't such now is to allow a less-than-perfect result to
# be obtained rather than raising an error or entering an
# infinite loop
for i in range(2):
new_c_powers = []
changed = False
for b, e in c_powers:
if e.is_zero:
# canceling out infinities yields NaN
if (b.is_Add or b.is_Mul) and any(infty in b.args
for infty in (S.ComplexInfinity, S.Infinity,
S.NegativeInfinity)):
return [S.NaN], [], None
continue
if e is S.One:
if b.is_Number:
coeff *= b
continue
p = b
if e is not S.One:
p = Pow(b, e)
# check to make sure that the base doesn't change
# after exponentiation; to allow for unevaluated
# Pow, we only do so if b is not already a Pow
if p.is_Pow and not b.is_Pow:
bi = b
b, e = p.as_base_exp()
if b != bi:
changed = True
c_part.append(p)
new_c_powers.append((b, e))
# there might have been a change, but unless the base
# matches some other base, there is nothing to do
if changed and len(set(
b for b, e in new_c_powers)) != len(new_c_powers):
# start over again
c_part = []
c_powers = _gather(new_c_powers)
else:
break
# x x x
# 2 * 3 -> 6
inv_exp_dict = {} # exp:Mul(num-bases) x x
# e.g. x:6 for ... * 2 * 3 * ...
for b, e in num_exp:
inv_exp_dict.setdefault(e, []).append(b)
for e, b in inv_exp_dict.items():
inv_exp_dict[e] = cls(*b)
c_part.extend([Pow(b, e) for e, b in inv_exp_dict.items() if e])
# b, e -> e' = sum(e), b
# {(1/5, [1/3]), (1/2, [1/12, 1/4]} -> {(1/3, [1/5, 1/2])}
comb_e = {}
for b, e in pnum_rat.items():
comb_e.setdefault(Add(*e), []).append(b)
del pnum_rat
# process them, reducing exponents to values less than 1
# and updating coeff if necessary else adding them to
# num_rat for further processing
num_rat = []
for e, b in comb_e.items():
b = cls(*b)
if e.q == 1:
coeff *= Pow(b, e)
continue
if e.p > e.q:
e_i, ep = divmod(e.p, e.q)
coeff *= Pow(b, e_i)
e = Rational(ep, e.q)
num_rat.append((b, e))
del comb_e
# extract gcd of bases in num_rat
# 2**(1/3)*6**(1/4) -> 2**(1/3+1/4)*3**(1/4)
pnew = defaultdict(list)
i = 0 # steps through num_rat which may grow
while i < len(num_rat):
bi, ei = num_rat[i]
grow = []
for j in range(i + 1, len(num_rat)):
bj, ej = num_rat[j]
g = bi.gcd(bj)
if g is not S.One:
# 4**r1*6**r2 -> 2**(r1+r2) * 2**r1 * 3**r2
# this might have a gcd with something else
e = ei + ej
if e.q == 1:
coeff *= Pow(g, e)
else:
if e.p > e.q:
e_i, ep = divmod(e.p, e.q) # change e in place
coeff *= Pow(g, e_i)
e = Rational(ep, e.q)
grow.append((g, e))
# update the jth item
num_rat[j] = (bj/g, ej)
# update bi that we are checking with
bi = bi/g
if bi is S.One:
break
if bi is not S.One:
obj = Pow(bi, ei)
if obj.is_Number:
coeff *= obj
else:
# changes like sqrt(12) -> 2*sqrt(3)
for obj in Mul.make_args(obj):
if obj.is_Number:
coeff *= obj
else:
assert obj.is_Pow
bi, ei = obj.args
pnew[ei].append(bi)
num_rat.extend(grow)
i += 1
# combine bases of the new powers
for e, b in pnew.items():
pnew[e] = cls(*b)
# handle -1 and I
if neg1e:
# treat I as (-1)**(1/2) and compute -1's total exponent
p, q = neg1e.as_numer_denom()
# if the integer part is odd, extract -1
n, p = divmod(p, q)
if n % 2:
coeff = -coeff
# if it's a multiple of 1/2 extract I
if q == 2:
c_part.append(S.ImaginaryUnit)
elif p:
# see if there is any positive base this power of
# -1 can join
neg1e = Rational(p, q)
for e, b in pnew.items():
if e == neg1e and b.is_positive:
pnew[e] = -b
break
else:
# keep it separate; we've already evaluated it as
# much as possible so evaluate=False
c_part.append(Pow(S.NegativeOne, neg1e, evaluate=False))
# add all the pnew powers
c_part.extend([Pow(b, e) for e, b in pnew.items()])
# oo, -oo
if (coeff is S.Infinity) or (coeff is S.NegativeInfinity):
def _handle_for_oo(c_part, coeff_sign):
new_c_part = []
for t in c_part:
if t.is_positive:
continue
if t.is_negative:
coeff_sign *= -1
continue
new_c_part.append(t)
return new_c_part, coeff_sign
c_part, coeff_sign = _handle_for_oo(c_part, 1)
nc_part, coeff_sign = _handle_for_oo(nc_part, coeff_sign)
coeff *= coeff_sign
# zoo
if coeff is S.ComplexInfinity:
# zoo might be
# infinite_real + bounded_im
# bounded_real + infinite_im
# infinite_real + infinite_im
# and non-zero real or imaginary will not change that status.
c_part = [c for c in c_part if not (fuzzy_not(c.is_zero) and
c.is_real is not None)]
nc_part = [c for c in nc_part if not (fuzzy_not(c.is_zero) and
c.is_real is not None)]
# 0
elif coeff is S.Zero:
# we know for sure the result will be 0 except the multiplicand
# is infinity
if any(c.is_finite == False for c in c_part):
return [S.NaN], [], order_symbols
return [coeff], [], order_symbols
# check for straggling Numbers that were produced
_new = []
for i in c_part:
if i.is_Number:
coeff *= i
else:
_new.append(i)
c_part = _new
# order commutative part canonically
_mulsort(c_part)
# current code expects coeff to be always in slot-0
if coeff is not S.One:
c_part.insert(0, coeff)
# we are done
if (global_distribute[0] and not nc_part and len(c_part) == 2 and
c_part[0].is_Number and c_part[0].is_finite and c_part[1].is_Add):
# 2*(1+a) -> 2 + 2 * a
coeff = c_part[0]
c_part = [Add(*[coeff*f for f in c_part[1].args])]
return c_part, nc_part, order_symbols
def _eval_power(b, e):
# don't break up NC terms: (A*B)**3 != A**3*B**3, it is A*B*A*B*A*B
cargs, nc = b.args_cnc(split_1=False)
if e.is_Integer:
return Mul(*[Pow(b, e, evaluate=False) for b in cargs]) * \
Pow(Mul._from_args(nc), e, evaluate=False)
if e.is_Rational and e.q == 2:
from sympy.core.power import integer_nthroot
from sympy.functions.elementary.complexes import sign
if b.is_imaginary:
a = b.as_real_imag()[1]
if a.is_Rational:
n, d = abs(a/2).as_numer_denom()
n, t = integer_nthroot(n, 2)
if t:
d, t = integer_nthroot(d, 2)
if t:
r = sympify(n)/d
return _unevaluated_Mul(r**e.p, (1 + sign(a)*S.ImaginaryUnit)**e.p)
p = Pow(b, e, evaluate=False)
if e.is_Rational or e.is_Float:
return p._eval_expand_power_base()
return p
@classmethod
def class_key(cls):
return 3, 0, cls.__name__
def _eval_evalf(self, prec):
c, m = self.as_coeff_Mul()
if c is S.NegativeOne:
if m.is_Mul:
rv = -AssocOp._eval_evalf(m, prec)
else:
mnew = m._eval_evalf(prec)
if mnew is not None:
m = mnew
rv = -m
else:
rv = AssocOp._eval_evalf(self, prec)
if rv.is_number:
return rv.expand()
return rv
@property
def _mpc_(self):
"""
Convert self to an mpmath mpc if possible
"""
from sympy.core.numbers import I, Float
im_part, imag_unit = self.as_coeff_Mul()
if not imag_unit == I:
# ValueError may seem more reasonable but since it's a @property,
# we need to use AttributeError to keep from confusing things like
# hasattr.
raise AttributeError("Cannot convert Mul to mpc. Must be of the form Number*I")
return (Float(0)._mpf_, Float(im_part)._mpf_)
@cacheit
def as_two_terms(self):
"""Return head and tail of self.
This is the most efficient way to get the head and tail of an
expression.
- if you want only the head, use self.args[0];
- if you want to process the arguments of the tail then use
self.as_coef_mul() which gives the head and a tuple containing
the arguments of the tail when treated as a Mul.
- if you want the coefficient when self is treated as an Add
then use self.as_coeff_add()[0]
>>> from sympy.abc import x, y
>>> (3*x*y).as_two_terms()
(3, x*y)
"""
args = self.args
if len(args) == 1:
return S.One, self
elif len(args) == 2:
return args
else:
return args[0], self._new_rawargs(*args[1:])
@cacheit
def as_coefficients_dict(self):
"""Return a dictionary mapping terms to their coefficient.
Since the dictionary is a defaultdict, inquiries about terms which
were not present will return a coefficient of 0. The dictionary
is considered to have a single term.
Examples
========
>>> from sympy.abc import a, x
>>> (3*a*x).as_coefficients_dict()
{a*x: 3}
>>> _[a]
0
"""
d = defaultdict(int)
args = self.args
if len(args) == 1 or not args[0].is_Number:
d[self] = S.One
else:
d[self._new_rawargs(*args[1:])] = args[0]
return d
@cacheit
def as_coeff_mul(self, *deps, **kwargs):
rational = kwargs.pop('rational', True)
if deps:
l1 = []
l2 = []
for f in self.args:
if f.has(*deps):
l2.append(f)
else:
l1.append(f)
return self._new_rawargs(*l1), tuple(l2)
args = self.args
if args[0].is_Number:
if not rational or args[0].is_Rational:
return args[0], args[1:]
elif args[0].is_negative:
return S.NegativeOne, (-args[0],) + args[1:]
return S.One, args
def as_coeff_Mul(self, rational=False):
"""Efficiently extract the coefficient of a product. """
coeff, args = self.args[0], self.args[1:]
if coeff.is_Number:
if not rational or coeff.is_Rational:
if len(args) == 1:
return coeff, args[0]
else:
return coeff, self._new_rawargs(*args)
elif coeff.is_negative:
return S.NegativeOne, self._new_rawargs(*((-coeff,) + args))
return S.One, self
def as_real_imag(self, deep=True, **hints):
from sympy import Abs, expand_mul, im, re
other = []
coeffr = []
coeffi = []
addterms = S.One
for a in self.args:
r, i = a.as_real_imag()
if i.is_zero:
coeffr.append(r)
elif r.is_zero:
coeffi.append(i*S.ImaginaryUnit)
elif a.is_commutative:
# search for complex conjugate pairs:
for i, x in enumerate(other):
if x == a.conjugate():
coeffr.append(Abs(x)**2)
del other[i]
break
else:
if a.is_Add:
addterms *= a
else:
other.append(a)
else:
other.append(a)
m = self.func(*other)
if hints.get('ignore') == m:
return
if len(coeffi) % 2:
imco = im(coeffi.pop(0))
# all other pairs make a real factor; they will be
# put into reco below
else:
imco = S.Zero
reco = self.func(*(coeffr + coeffi))
r, i = (reco*re(m), reco*im(m))
if addterms == 1:
if m == 1:
if imco is S.Zero:
return (reco, S.Zero)
else:
return (S.Zero, reco*imco)
if imco is S.Zero:
return (r, i)
return (-imco*i, imco*r)
addre, addim = expand_mul(addterms, deep=False).as_real_imag()
if imco is S.Zero:
return (r*addre - i*addim, i*addre + r*addim)
else:
r, i = -imco*i, imco*r
return (r*addre - i*addim, r*addim + i*addre)
@staticmethod
def _expandsums(sums):
"""
Helper function for _eval_expand_mul.
sums must be a list of instances of Basic.
"""
L = len(sums)
if L == 1:
return sums[0].args
terms = []
left = Mul._expandsums(sums[:L//2])
right = Mul._expandsums(sums[L//2:])
terms = [Mul(a, b) for a in left for b in right]
added = Add(*terms)
return Add.make_args(added) # it may have collapsed down to one term
def _eval_expand_mul(self, **hints):
from sympy import fraction
# Handle things like 1/(x*(x + 1)), which are automatically converted
# to 1/x*1/(x + 1)
expr = self
n, d = fraction(expr)
if d.is_Mul:
n, d = [i._eval_expand_mul(**hints) if i.is_Mul else i
for i in (n, d)]
expr = n/d
if not expr.is_Mul:
return expr
plain, sums, rewrite = [], [], False
for factor in expr.args:
if factor.is_Add:
sums.append(factor)
rewrite = True
else:
if factor.is_commutative:
plain.append(factor)
else:
sums.append(Basic(factor)) # Wrapper
if not rewrite:
return expr
else:
plain = self.func(*plain)
if sums:
deep = hints.get("deep", False)
terms = self.func._expandsums(sums)
args = []
for term in terms:
t = self.func(plain, term)
if t.is_Mul and any(a.is_Add for a in t.args) and deep:
t = t._eval_expand_mul()
args.append(t)
return Add(*args)
else:
return plain
@cacheit
def _eval_derivative(self, s):
args = list(self.args)
terms = []
for i in range(len(args)):
d = args[i].diff(s)
if d:
# Note: reduce is used in step of Mul as Mul is unable to
# handle subtypes and operation priority:
terms.append(reduce(lambda x, y: x*y, (args[:i] + [d] + args[i + 1:]), S.One))
return reduce(lambda x, y: x+y, terms, S.Zero)
@cacheit
def _eval_derivative_n_times(self, s, n):
from sympy import Integer, factorial, prod, Sum, Max
from sympy.ntheory.multinomial import multinomial_coefficients_iterator
from .function import AppliedUndef
from .symbol import Symbol, symbols, Dummy
if not isinstance(s, AppliedUndef) and not isinstance(s, Symbol):
# other types of s may not be well behaved, e.g.
# (cos(x)*sin(y)).diff([[x, y, z]])
return super(Mul, self)._eval_derivative_n_times(s, n)
args = self.args
m = len(args)
if isinstance(n, (int, Integer)):
# https://en.wikipedia.org/wiki/General_Leibniz_rule#More_than_two_factors
terms = []
for kvals, c in multinomial_coefficients_iterator(m, n):
p = prod([arg.diff((s, k)) for k, arg in zip(kvals, args)])
terms.append(c * p)
return Add(*terms)
kvals = symbols("k1:%i" % m, cls=Dummy)
klast = n - sum(kvals)
nfact = factorial(n)
e, l = (# better to use the multinomial?
nfact/prod(map(factorial, kvals))/factorial(klast)*\
prod([args[t].diff((s, kvals[t])) for t in range(m-1)])*\
args[-1].diff((s, Max(0, klast))),
[(k, 0, n) for k in kvals])
return Sum(e, *l)
def _eval_difference_delta(self, n, step):
from sympy.series.limitseq import difference_delta as dd
arg0 = self.args[0]
rest = Mul(*self.args[1:])
return (arg0.subs(n, n + step) * dd(rest, n, step) + dd(arg0, n, step) *
rest)
def _matches_simple(self, expr, repl_dict):
# handle (w*3).matches('x*5') -> {w: x*5/3}
coeff, terms = self.as_coeff_Mul()
terms = Mul.make_args(terms)
if len(terms) == 1:
newexpr = self.__class__._combine_inverse(expr, coeff)
return terms[0].matches(newexpr, repl_dict)
return
def matches(self, expr, repl_dict={}, old=False):
expr = sympify(expr)
if self.is_commutative and expr.is_commutative:
return AssocOp._matches_commutative(self, expr, repl_dict, old)
elif self.is_commutative is not expr.is_commutative:
return None
c1, nc1 = self.args_cnc()
c2, nc2 = expr.args_cnc()
repl_dict = repl_dict.copy()
if c1:
if not c2:
c2 = [1]
a = self.func(*c1)
if isinstance(a, AssocOp):
repl_dict = a._matches_commutative(self.func(*c2), repl_dict, old)
else:
repl_dict = a.matches(self.func(*c2), repl_dict)
if repl_dict:
a = self.func(*nc1)
if isinstance(a, self.func):
repl_dict = a._matches(self.func(*nc2), repl_dict)
else:
repl_dict = a.matches(self.func(*nc2), repl_dict)
return repl_dict or None
def _matches(self, expr, repl_dict={}):
# weed out negative one prefixes#
from sympy import Wild
sign = 1
a, b = self.as_two_terms()
if a is S.NegativeOne:
if b.is_Mul:
sign = -sign
else:
# the remainder, b, is not a Mul anymore
return b.matches(-expr, repl_dict)
expr = sympify(expr)
if expr.is_Mul and expr.args[0] is S.NegativeOne:
expr = -expr
sign = -sign
if not expr.is_Mul:
# expr can only match if it matches b and a matches +/- 1
if len(self.args) == 2:
# quickly test for equality
if b == expr:
return a.matches(Rational(sign), repl_dict)
# do more expensive match
dd = b.matches(expr, repl_dict)
if dd is None:
return None
dd = a.matches(Rational(sign), dd)
return dd
return None
d = repl_dict.copy()
# weed out identical terms
pp = list(self.args)
ee = list(expr.args)
for p in self.args:
if p in expr.args:
ee.remove(p)
pp.remove(p)
# only one symbol left in pattern -> match the remaining expression
if len(pp) == 1 and isinstance(pp[0], Wild):
if len(ee) == 1:
d[pp[0]] = sign * ee[0]
else:
d[pp[0]] = sign * expr.func(*ee)
return d
if len(ee) != len(pp):
return None
for p, e in zip(pp, ee):
d = p.xreplace(d).matches(e, d)
if d is None:
return None
return d
@staticmethod
def _combine_inverse(lhs, rhs):
"""
Returns lhs/rhs, but treats arguments like symbols, so things like
oo/oo return 1, instead of a nan.
"""
if lhs == rhs:
return S.One
def check(l, r):
if l.is_Float and r.is_comparable:
# if both objects are added to 0 they will share the same "normalization"
# and are more likely to compare the same. Since Add(foo, 0) will not allow
# the 0 to pass, we use __add__ directly.
return l.__add__(0) == r.evalf().__add__(0)
return False
if check(lhs, rhs) or check(rhs, lhs):
return S.One
if lhs.is_Mul and rhs.is_Mul:
a = list(lhs.args)
b = [1]
for x in rhs.args:
if x in a:
a.remove(x)
elif -x in a:
a.remove(-x)
b.append(-1)
else:
b.append(x)
return lhs.func(*a)/rhs.func(*b)
return lhs/rhs
def as_powers_dict(self):
d = defaultdict(int)
for term in self.args:
b, e = term.as_base_exp()
d[b] += e
return d
def as_numer_denom(self):
# don't use _from_args to rebuild the numerators and denominators
# as the order is not guaranteed to be the same once they have
# been separated from each other
numers, denoms = list(zip(*[f.as_numer_denom() for f in self.args]))
return self.func(*numers), self.func(*denoms)
def as_base_exp(self):
e1 = None
bases = []
nc = 0
for m in self.args:
b, e = m.as_base_exp()
if not b.is_commutative:
nc += 1
if e1 is None:
e1 = e
elif e != e1 or nc > 1:
return self, S.One
bases.append(b)
return self.func(*bases), e1
def _eval_is_polynomial(self, syms):
return all(term._eval_is_polynomial(syms) for term in self.args)
def _eval_is_rational_function(self, syms):
return all(term._eval_is_rational_function(syms) for term in self.args)
def _eval_is_algebraic_expr(self, syms):
return all(term._eval_is_algebraic_expr(syms) for term in self.args)
_eval_is_finite = lambda self: _fuzzy_group(
a.is_finite for a in self.args)
_eval_is_commutative = lambda self: _fuzzy_group(
a.is_commutative for a in self.args)
_eval_is_complex = lambda self: _fuzzy_group(
(a.is_complex for a in self.args), quick_exit=True)
def _eval_is_infinite(self):
if any(a.is_infinite for a in self.args):
if any(a.is_zero for a in self.args):
return S.NaN.is_infinite
if any(a.is_zero is None for a in self.args):
return None
return True
def _eval_is_rational(self):
r = _fuzzy_group((a.is_rational for a in self.args), quick_exit=True)
if r:
return r
elif r is False:
return self.is_zero
def _eval_is_algebraic(self):
r = _fuzzy_group((a.is_algebraic for a in self.args), quick_exit=True)
if r:
return r
elif r is False:
return self.is_zero
def _eval_is_zero(self):
zero = infinite = False
for a in self.args:
z = a.is_zero
if z:
if infinite:
return # 0*oo is nan and nan.is_zero is None
zero = True
else:
if not a.is_finite:
if zero:
return # 0*oo is nan and nan.is_zero is None
infinite = True
if zero is False and z is None: # trap None
zero = None
return zero
def _eval_is_integer(self):
is_rational = self.is_rational
if is_rational:
n, d = self.as_numer_denom()
if d is S.One:
return True
elif d is S(2):
return n.is_even
elif is_rational is False:
return False
def _eval_is_polar(self):
has_polar = any(arg.is_polar for arg in self.args)
return has_polar and \
all(arg.is_polar or arg.is_positive for arg in self.args)
def _eval_is_real(self):
return self._eval_real_imag(True)
def _eval_real_imag(self, real):
zero = False
t_not_re_im = None
for t in self.args:
if not t.is_complex:
return t.is_complex
elif t.is_imaginary: # I
real = not real
elif t.is_real: # 2
if not zero:
z = t.is_zero
if not z and zero is False:
zero = z
elif z:
if all(a.is_finite for a in self.args):
return True
return
elif t.is_real is False:
# symbolic or literal like `2 + I` or symbolic imaginary
if t_not_re_im:
return # complex terms might cancel
t_not_re_im = t
elif t.is_imaginary is False: # symbolic like `2` or `2 + I`
if t_not_re_im:
return # complex terms might cancel
t_not_re_im = t
else:
return
if t_not_re_im:
if t_not_re_im.is_real is False:
if real: # like 3
return zero # 3*(smthng like 2 + I or i) is not real
if t_not_re_im.is_imaginary is False: # symbolic 2 or 2 + I
if not real: # like I
return zero # I*(smthng like 2 or 2 + I) is not real
elif zero is False:
return real # can't be trumped by 0
elif real:
return real # doesn't matter what zero is
def _eval_is_imaginary(self):
z = self.is_zero
if z:
return False
elif z is False:
return self._eval_real_imag(False)
def _eval_is_hermitian(self):
return self._eval_herm_antiherm(True)
def _eval_herm_antiherm(self, real):
one_nc = zero = one_neither = False
for t in self.args:
if not t.is_commutative:
if one_nc:
return
one_nc = True
if t.is_antihermitian:
real = not real
elif t.is_hermitian:
if not zero:
z = t.is_zero
if not z and zero is False:
zero = z
elif z:
if all(a.is_finite for a in self.args):
return True
return
elif t.is_hermitian is False:
if one_neither:
return
one_neither = True
else:
return
if one_neither:
if real:
return zero
elif zero is False or real:
return real
def _eval_is_antihermitian(self):
z = self.is_zero
if z:
return False
elif z is False:
return self._eval_herm_antiherm(False)
def _eval_is_irrational(self):
for t in self.args:
a = t.is_irrational
if a:
others = list(self.args)
others.remove(t)
if all((x.is_rational and fuzzy_not(x.is_zero)) is True for x in others):
return True
return
if a is None:
return
return False
def _eval_is_positive(self):
"""Return True if self is positive, False if not, and None if it
cannot be determined.
This algorithm is non-recursive and works by keeping track of the
sign which changes when a negative or nonpositive is encountered.
Whether a nonpositive or nonnegative is seen is also tracked since
the presence of these makes it impossible to return True, but
possible to return False if the end result is nonpositive. e.g.
pos * neg * nonpositive -> pos or zero -> None is returned
pos * neg * nonnegative -> neg or zero -> False is returned
"""
return self._eval_pos_neg(1)
def _eval_pos_neg(self, sign):
saw_NON = saw_NOT = False
for t in self.args:
if t.is_positive:
continue
elif t.is_negative:
sign = -sign
elif t.is_zero:
if all(a.is_finite for a in self.args):
return False
return
elif t.is_nonpositive:
sign = -sign
saw_NON = True
elif t.is_nonnegative:
saw_NON = True
elif t.is_positive is False:
sign = -sign
if saw_NOT:
return
saw_NOT = True
elif t.is_negative is False:
if saw_NOT:
return
saw_NOT = True
else:
return
if sign == 1 and saw_NON is False and saw_NOT is False:
return True
if sign < 0:
return False
def _eval_is_negative(self):
if self.args[0] == -1:
return (-self).is_positive # remove -1
return self._eval_pos_neg(-1)
def _eval_is_odd(self):
is_integer = self.is_integer
if is_integer:
r, acc = True, 1
for t in self.args:
if not t.is_integer:
return None
elif t.is_even:
r = False
elif t.is_integer:
if r is False:
pass
elif acc != 1 and (acc + t).is_odd:
r = False
elif t.is_odd is None:
r = None
acc = t
return r
# !integer -> !odd
elif is_integer is False:
return False
def _eval_is_even(self):
is_integer = self.is_integer
if is_integer:
return fuzzy_not(self.is_odd)
elif is_integer is False:
return False
def _eval_is_composite(self):
if self.is_integer and self.is_positive:
"""
Here we count the number of arguments that have a minimum value
greater than two.
If there are more than one of such a symbol then the result is composite.
Else, the result cannot be determined.
"""
number_of_args = 0 # count of symbols with minimum value greater than one
for arg in self.args:
if (arg-1).is_positive:
number_of_args += 1
if number_of_args > 1:
return True
def _eval_subs(self, old, new):
from sympy.functions.elementary.complexes import sign
from sympy.ntheory.factor_ import multiplicity
from sympy.simplify.powsimp import powdenest
from sympy.simplify.radsimp import fraction
if not old.is_Mul:
return None
# try keep replacement literal so -2*x doesn't replace 4*x
if old.args[0].is_Number and old.args[0] < 0:
if self.args[0].is_Number:
if self.args[0] < 0:
return self._subs(-old, -new)
return None
def base_exp(a):
# if I and -1 are in a Mul, they get both end up with
# a -1 base (see issue 6421); all we want here are the
# true Pow or exp separated into base and exponent
from sympy import exp
if a.is_Pow or isinstance(a, exp):
return a.as_base_exp()
return a, S.One
def breakup(eq):
"""break up powers of eq when treated as a Mul:
b**(Rational*e) -> b**e, Rational
commutatives come back as a dictionary {b**e: Rational}
noncommutatives come back as a list [(b**e, Rational)]
"""
(c, nc) = (defaultdict(int), list())
for a in Mul.make_args(eq):
a = powdenest(a)
(b, e) = base_exp(a)
if e is not S.One:
(co, _) = e.as_coeff_mul()
b = Pow(b, e/co)
e = co
if a.is_commutative:
c[b] += e
else:
nc.append([b, e])
return (c, nc)
def rejoin(b, co):
"""
Put rational back with exponent; in general this is not ok, but
since we took it from the exponent for analysis, it's ok to put
it back.
"""
(b, e) = base_exp(b)
return Pow(b, e*co)
def ndiv(a, b):
"""if b divides a in an extractive way (like 1/4 divides 1/2
but not vice versa, and 2/5 does not divide 1/3) then return
the integer number of times it divides, else return 0.
"""
if not b.q % a.q or not a.q % b.q:
return int(a/b)
return 0
# give Muls in the denominator a chance to be changed (see issue 5651)
# rv will be the default return value
rv = None
n, d = fraction(self)
self2 = self
if d is not S.One:
self2 = n._subs(old, new)/d._subs(old, new)
if not self2.is_Mul:
return self2._subs(old, new)
if self2 != self:
rv = self2
# Now continue with regular substitution.
# handle the leading coefficient and use it to decide if anything
# should even be started; we always know where to find the Rational
# so it's a quick test
co_self = self2.args[0]
co_old = old.args[0]
co_xmul = None
if co_old.is_Rational and co_self.is_Rational:
# if coeffs are the same there will be no updating to do
# below after breakup() step; so skip (and keep co_xmul=None)
if co_old != co_self:
co_xmul = co_self.extract_multiplicatively(co_old)
elif co_old.is_Rational:
return rv
# break self and old into factors
(c, nc) = breakup(self2)
(old_c, old_nc) = breakup(old)
# update the coefficients if we had an extraction
# e.g. if co_self were 2*(3/35*x)**2 and co_old = 3/5
# then co_self in c is replaced by (3/5)**2 and co_residual
# is 2*(1/7)**2
if co_xmul and co_xmul.is_Rational and abs(co_old) != 1:
mult = S(multiplicity(abs(co_old), co_self))
c.pop(co_self)
if co_old in c:
c[co_old] += mult
else:
c[co_old] = mult
co_residual = co_self/co_old**mult
else:
co_residual = 1
# do quick tests to see if we can't succeed
ok = True
if len(old_nc) > len(nc):
# more non-commutative terms
ok = False
elif len(old_c) > len(c):
# more commutative terms
ok = False
elif set(i[0] for i in old_nc).difference(set(i[0] for i in nc)):
# unmatched non-commutative bases
ok = False
elif set(old_c).difference(set(c)):
# unmatched commutative terms
ok = False
elif any(sign(c[b]) != sign(old_c[b]) for b in old_c):
# differences in sign
ok = False
if not ok:
return rv
if not old_c:
cdid = None
else:
rat = []
for (b, old_e) in old_c.items():
c_e = c[b]
rat.append(ndiv(c_e, old_e))
if not rat[-1]:
return rv
cdid = min(rat)
if not old_nc:
ncdid = None
for i in range(len(nc)):
nc[i] = rejoin(*nc[i])
else:
ncdid = 0 # number of nc replacements we did
take = len(old_nc) # how much to look at each time
limit = cdid or S.Infinity # max number that we can take
failed = [] # failed terms will need subs if other terms pass
i = 0
while limit and i + take <= len(nc):
hit = False
# the bases must be equivalent in succession, and
# the powers must be extractively compatible on the
# first and last factor but equal in between.
rat = []
for j in range(take):
if nc[i + j][0] != old_nc[j][0]:
break
elif j == 0:
rat.append(ndiv(nc[i + j][1], old_nc[j][1]))
elif j == take - 1:
rat.append(ndiv(nc[i + j][1], old_nc[j][1]))
elif nc[i + j][1] != old_nc[j][1]:
break
else:
rat.append(1)
j += 1
else:
ndo = min(rat)
if ndo:
if take == 1:
if cdid:
ndo = min(cdid, ndo)
nc[i] = Pow(new, ndo)*rejoin(nc[i][0],
nc[i][1] - ndo*old_nc[0][1])
else:
ndo = 1
# the left residual
l = rejoin(nc[i][0], nc[i][1] - ndo*
old_nc[0][1])
# eliminate all middle terms
mid = new
# the right residual (which may be the same as the middle if take == 2)
ir = i + take - 1
r = (nc[ir][0], nc[ir][1] - ndo*
old_nc[-1][1])
if r[1]:
if i + take < len(nc):
nc[i:i + take] = [l*mid, r]
else:
r = rejoin(*r)
nc[i:i + take] = [l*mid*r]
else:
# there was nothing left on the right
nc[i:i + take] = [l*mid]
limit -= ndo
ncdid += ndo
hit = True
if not hit:
# do the subs on this failing factor
failed.append(i)
i += 1
else:
if not ncdid:
return rv
# although we didn't fail, certain nc terms may have
# failed so we rebuild them after attempting a partial
# subs on them
failed.extend(range(i, len(nc)))
for i in failed:
nc[i] = rejoin(*nc[i]).subs(old, new)
# rebuild the expression
if cdid is None:
do = ncdid
elif ncdid is None:
do = cdid
else:
do = min(ncdid, cdid)
margs = []
for b in c:
if b in old_c:
# calculate the new exponent
e = c[b] - old_c[b]*do
margs.append(rejoin(b, e))
else:
margs.append(rejoin(b.subs(old, new), c[b]))
if cdid and not ncdid:
# in case we are replacing commutative with non-commutative,
# we want the new term to come at the front just like the
# rest of this routine
margs = [Pow(new, cdid)] + margs
return co_residual*self2.func(*margs)*self2.func(*nc)
def _eval_nseries(self, x, n, logx):
from sympy import Order, powsimp
terms = [t.nseries(x, n=n, logx=logx) for t in self.args]
res = powsimp(self.func(*terms).expand(), combine='exp', deep=True)
if res.has(Order):
res += Order(x**n, x)
return res
def _eval_as_leading_term(self, x):
return self.func(*[t.as_leading_term(x) for t in self.args])
def _eval_conjugate(self):
return self.func(*[t.conjugate() for t in self.args])
def _eval_transpose(self):
return self.func(*[t.transpose() for t in self.args[::-1]])
def _eval_adjoint(self):
return self.func(*[t.adjoint() for t in self.args[::-1]])
def _sage_(self):
s = 1
for x in self.args:
s *= x._sage_()
return s
def as_content_primitive(self, radical=False, clear=True):
"""Return the tuple (R, self/R) where R is the positive Rational
extracted from self.
Examples
========
>>> from sympy import sqrt
>>> (-3*sqrt(2)*(2 - 2*sqrt(2))).as_content_primitive()
(6, -sqrt(2)*(-sqrt(2) + 1))
See docstring of Expr.as_content_primitive for more examples.
"""
coef = S.One
args = []
for i, a in enumerate(self.args):
c, p = a.as_content_primitive(radical=radical, clear=clear)
coef *= c
if p is not S.One:
args.append(p)
# don't use self._from_args here to reconstruct args
# since there may be identical args now that should be combined
# e.g. (2+2*x)*(3+3*x) should be (6, (1 + x)**2) not (6, (1+x)*(1+x))
return coef, self.func(*args)
def as_ordered_factors(self, order=None):
"""Transform an expression into an ordered list of factors.
Examples
========
>>> from sympy import sin, cos
>>> from sympy.abc import x, y
>>> (2*x*y*sin(x)*cos(x)).as_ordered_factors()
[2, x, y, sin(x), cos(x)]
"""
cpart, ncpart = self.args_cnc()
cpart.sort(key=lambda expr: expr.sort_key(order=order))
return cpart + ncpart
@property
def _sorted_args(self):
return tuple(self.as_ordered_factors())
def prod(a, start=1):
"""Return product of elements of a. Start with int 1 so if only
ints are included then an int result is returned.
Examples
========
>>> from sympy import prod, S
>>> prod(range(3))
0
>>> type(_) is int
True
>>> prod([S(2), 3])
6
>>> _.is_Integer
True
You can start the product at something other than 1:
>>> prod([1, 2], 3)
6
"""
return reduce(operator.mul, a, start)
def _keep_coeff(coeff, factors, clear=True, sign=False):
"""Return ``coeff*factors`` unevaluated if necessary.
If ``clear`` is False, do not keep the coefficient as a factor
if it can be distributed on a single factor such that one or
more terms will still have integer coefficients.
If ``sign`` is True, allow a coefficient of -1 to remain factored out.
Examples
========
>>> from sympy.core.mul import _keep_coeff
>>> from sympy.abc import x, y
>>> from sympy import S
>>> _keep_coeff(S.Half, x + 2)
(x + 2)/2
>>> _keep_coeff(S.Half, x + 2, clear=False)
x/2 + 1
>>> _keep_coeff(S.Half, (x + 2)*y, clear=False)
y*(x + 2)/2
>>> _keep_coeff(S(-1), x + y)
-x - y
>>> _keep_coeff(S(-1), x + y, sign=True)
-(x + y)
"""
if not coeff.is_Number:
if factors.is_Number:
factors, coeff = coeff, factors
else:
return coeff*factors
if coeff is S.One:
return factors
elif coeff is S.NegativeOne and not sign:
return -factors
elif factors.is_Add:
if not clear and coeff.is_Rational and coeff.q != 1:
q = S(coeff.q)
for i in factors.args:
c, t = i.as_coeff_Mul()
r = c/q
if r == int(r):
return coeff*factors
return Mul._from_args((coeff, factors))
elif factors.is_Mul:
margs = list(factors.args)
if margs[0].is_Number:
margs[0] *= coeff
if margs[0] == 1:
margs.pop(0)
else:
margs.insert(0, coeff)
return Mul._from_args(margs)
else:
return coeff*factors
def expand_2arg(e):
from sympy.simplify.simplify import bottom_up
def do(e):
if e.is_Mul:
c, r = e.as_coeff_Mul()
if c.is_Number and r.is_Add:
return _unevaluated_Add(*[c*ri for ri in r.args])
return e
return bottom_up(e, do)
from .numbers import Rational
from .power import Pow
from .add import Add, _addsort, _unevaluated_Add
|
72ecb90e59fbbe76b6b4d29c06a226868d2f6ad9de41ca546ae6924891fb9294
|
"""Tools for setting up printing in interactive sessions. """
from __future__ import print_function, division
import sys
from distutils.version import LooseVersion as V
from io import BytesIO
from sympy import latex as default_latex
from sympy import preview
from sympy.core.compatibility import integer_types
from sympy.utilities.misc import debug
def _init_python_printing(stringify_func, **settings):
"""Setup printing in Python interactive session. """
import sys
from sympy.core.compatibility import builtins
def _displayhook(arg):
"""Python's pretty-printer display hook.
This function was adapted from:
http://www.python.org/dev/peps/pep-0217/
"""
if arg is not None:
builtins._ = None
print(stringify_func(arg, **settings))
builtins._ = arg
sys.displayhook = _displayhook
def _init_ipython_printing(ip, stringify_func, use_latex, euler, forecolor,
backcolor, fontsize, latex_mode, print_builtin,
latex_printer, **settings):
"""Setup printing in IPython interactive session. """
try:
from IPython.lib.latextools import latex_to_png
except ImportError:
pass
preamble = "\\documentclass[varwidth,%s]{standalone}\n" \
"\\usepackage{amsmath,amsfonts}%s\\begin{document}"
if euler:
addpackages = '\\usepackage{euler}'
else:
addpackages = ''
preamble = preamble % (fontsize, addpackages)
imagesize = 'tight'
offset = "0cm,0cm"
resolution = 150
dvi = r"-T %s -D %d -bg %s -fg %s -O %s" % (
imagesize, resolution, backcolor, forecolor, offset)
dvioptions = dvi.split()
debug("init_printing: DVIOPTIONS:", dvioptions)
debug("init_printing: PREAMBLE:", preamble)
latex = latex_printer or default_latex
def _print_plain(arg, p, cycle):
"""caller for pretty, for use in IPython 0.11"""
if _can_print_latex(arg):
p.text(stringify_func(arg))
else:
p.text(IPython.lib.pretty.pretty(arg))
def _preview_wrapper(o):
exprbuffer = BytesIO()
try:
preview(o, output='png', viewer='BytesIO',
outputbuffer=exprbuffer, preamble=preamble,
dvioptions=dvioptions)
except Exception as e:
# IPython swallows exceptions
debug("png printing:", "_preview_wrapper exception raised:",
repr(e))
raise
return exprbuffer.getvalue()
def _matplotlib_wrapper(o):
# mathtext does not understand certain latex flags, so we try to
# replace them with suitable subs
o = o.replace(r'\operatorname', '')
o = o.replace(r'\overline', r'\bar')
# mathtext can't render some LaTeX commands. For example, it can't
# render any LaTeX environments such as array or matrix. So here we
# ensure that if mathtext fails to render, we return None.
try:
return latex_to_png(o)
except ValueError as e:
debug('matplotlib exception caught:', repr(e))
return None
from sympy import Basic
from sympy.matrices import MatrixBase
from sympy.physics.vector import Vector, Dyadic
from sympy.tensor.array import NDimArray
# These should all have _repr_latex_ and _repr_latex_orig. If you update
# this also update printable_types below.
sympy_latex_types = (Basic, MatrixBase, Vector, Dyadic, NDimArray)
def _can_print_latex(o):
"""Return True if type o can be printed with LaTeX.
If o is a container type, this is True if and only if every element of
o can be printed with LaTeX.
"""
try:
# If you're adding another type, make sure you add it to printable_types
# later in this file as well
builtin_types = (list, tuple, set, frozenset)
if isinstance(o, builtin_types):
# If the object is a custom subclass with a custom str or
# repr, use that instead.
if (type(o).__str__ not in (i.__str__ for i in builtin_types) or
type(o).__repr__ not in (i.__repr__ for i in builtin_types)):
return False
return all(_can_print_latex(i) for i in o)
elif isinstance(o, dict):
return all(_can_print_latex(i) and _can_print_latex(o[i]) for i in o)
elif isinstance(o, bool):
return False
# TODO : Investigate if "elif hasattr(o, '_latex')" is more useful
# to use here, than these explicit imports.
elif isinstance(o, sympy_latex_types):
return True
elif isinstance(o, (float, integer_types)) and print_builtin:
return True
return False
except RuntimeError:
return False
# This is in case maximum recursion depth is reached.
# Since RecursionError is for versions of Python 3.5+
# so this is to guard against RecursionError for older versions.
def _print_latex_png(o):
"""
A function that returns a png rendered by an external latex
distribution, falling back to matplotlib rendering
"""
if _can_print_latex(o):
s = latex(o, mode=latex_mode, **settings)
if latex_mode == 'plain':
s = '$\\displaystyle %s$' % s
try:
return _preview_wrapper(s)
except RuntimeError as e:
debug('preview failed with:', repr(e),
' Falling back to matplotlib backend')
if latex_mode != 'inline':
s = latex(o, mode='inline', **settings)
return _matplotlib_wrapper(s)
def _print_latex_matplotlib(o):
"""
A function that returns a png rendered by mathtext
"""
if _can_print_latex(o):
s = latex(o, mode='inline', **settings)
return _matplotlib_wrapper(s)
def _print_latex_text(o):
"""
A function to generate the latex representation of sympy expressions.
"""
if _can_print_latex(o):
s = latex(o, mode=latex_mode, **settings)
if latex_mode == 'plain':
return '$\\displaystyle %s$' % s
return s
def _result_display(self, arg):
"""IPython's pretty-printer display hook, for use in IPython 0.10
This function was adapted from:
ipython/IPython/hooks.py:155
"""
if self.rc.pprint:
out = stringify_func(arg)
if '\n' in out:
print
print(out)
else:
print(repr(arg))
import IPython
if V(IPython.__version__) >= '0.11':
from sympy.core.basic import Basic
from sympy.matrices.matrices import MatrixBase
from sympy.physics.vector import Vector, Dyadic
from sympy.tensor.array import NDimArray
printable_types = [Basic, MatrixBase, float, tuple, list, set,
frozenset, dict, Vector, Dyadic, NDimArray] + list(integer_types)
plaintext_formatter = ip.display_formatter.formatters['text/plain']
for cls in printable_types:
plaintext_formatter.for_type(cls, _print_plain)
png_formatter = ip.display_formatter.formatters['image/png']
if use_latex in (True, 'png'):
debug("init_printing: using png formatter")
for cls in printable_types:
png_formatter.for_type(cls, _print_latex_png)
elif use_latex == 'matplotlib':
debug("init_printing: using matplotlib formatter")
for cls in printable_types:
png_formatter.for_type(cls, _print_latex_matplotlib)
else:
debug("init_printing: not using any png formatter")
for cls in printable_types:
# Better way to set this, but currently does not work in IPython
#png_formatter.for_type(cls, None)
if cls in png_formatter.type_printers:
png_formatter.type_printers.pop(cls)
latex_formatter = ip.display_formatter.formatters['text/latex']
if use_latex in (True, 'mathjax'):
debug("init_printing: using mathjax formatter")
for cls in printable_types:
latex_formatter.for_type(cls, _print_latex_text)
for typ in sympy_latex_types:
typ._repr_latex_ = typ._repr_latex_orig
else:
debug("init_printing: not using text/latex formatter")
for cls in printable_types:
# Better way to set this, but currently does not work in IPython
#latex_formatter.for_type(cls, None)
if cls in latex_formatter.type_printers:
latex_formatter.type_printers.pop(cls)
for typ in sympy_latex_types:
typ._repr_latex_ = None
else:
ip.set_hook('result_display', _result_display)
def _is_ipython(shell):
"""Is a shell instance an IPython shell?"""
# shortcut, so we don't import IPython if we don't have to
if 'IPython' not in sys.modules:
return False
try:
from IPython.core.interactiveshell import InteractiveShell
except ImportError:
# IPython < 0.11
try:
from IPython.iplib import InteractiveShell
except ImportError:
# Reaching this points means IPython has changed in a backward-incompatible way
# that we don't know about. Warn?
return False
return isinstance(shell, InteractiveShell)
# Used by the doctester to override the default for no_global
NO_GLOBAL = False
def init_printing(pretty_print=True, order=None, use_unicode=None,
use_latex=None, wrap_line=None, num_columns=None,
no_global=False, ip=None, euler=False, forecolor='Black',
backcolor='Transparent', fontsize='10pt',
latex_mode='plain', print_builtin=True,
str_printer=None, pretty_printer=None,
latex_printer=None, **settings):
r"""
Initializes pretty-printer depending on the environment.
Parameters
==========
pretty_print: boolean
If True, use pretty_print to stringify or the provided pretty
printer; if False, use sstrrepr to stringify or the provided string
printer.
order: string or None
There are a few different settings for this parameter:
lex (default), which is lexographic order;
grlex, which is graded lexographic order;
grevlex, which is reversed graded lexographic order;
old, which is used for compatibility reasons and for long expressions;
None, which sets it to lex.
use_unicode: boolean or None
If True, use unicode characters;
if False, do not use unicode characters.
use_latex: string, boolean, or None
If True, use default latex rendering in GUI interfaces (png and
mathjax);
if False, do not use latex rendering;
if 'png', enable latex rendering with an external latex compiler,
falling back to matplotlib if external compilation fails;
if 'matplotlib', enable latex rendering with matplotlib;
if 'mathjax', enable latex text generation, for example MathJax
rendering in IPython notebook or text rendering in LaTeX documents
wrap_line: boolean
If True, lines will wrap at the end; if False, they will not wrap
but continue as one line. This is only relevant if `pretty_print` is
True.
num_columns: int or None
If int, number of columns before wrapping is set to num_columns; if
None, number of columns before wrapping is set to terminal width.
This is only relevant if `pretty_print` is True.
no_global: boolean
If True, the settings become system wide;
if False, use just for this console/session.
ip: An interactive console
This can either be an instance of IPython,
or a class that derives from code.InteractiveConsole.
euler: boolean, optional, default=False
Loads the euler package in the LaTeX preamble for handwritten style
fonts (http://www.ctan.org/pkg/euler).
forecolor: string, optional, default='Black'
DVI setting for foreground color.
backcolor: string, optional, default='Transparent'
DVI setting for background color.
fontsize: string, optional, default='10pt'
A font size to pass to the LaTeX documentclass function in the
preamble.
latex_mode: string, optional, default='plain'
The mode used in the LaTeX printer. Can be one of:
{'inline'|'plain'|'equation'|'equation*'}.
print_builtin: boolean, optional, default=True
If true then floats and integers will be printed. If false the
printer will only print SymPy types.
str_printer: function, optional, default=None
A custom string printer function. This should mimic
sympy.printing.sstrrepr().
pretty_printer: function, optional, default=None
A custom pretty printer. This should mimic sympy.printing.pretty().
latex_printer: function, optional, default=None
A custom LaTeX printer. This should mimic sympy.printing.latex().
Examples
========
>>> from sympy.interactive import init_printing
>>> from sympy import Symbol, sqrt
>>> from sympy.abc import x, y
>>> sqrt(5)
sqrt(5)
>>> init_printing(pretty_print=True) # doctest: +SKIP
>>> sqrt(5) # doctest: +SKIP
___
\/ 5
>>> theta = Symbol('theta') # doctest: +SKIP
>>> init_printing(use_unicode=True) # doctest: +SKIP
>>> theta # doctest: +SKIP
\u03b8
>>> init_printing(use_unicode=False) # doctest: +SKIP
>>> theta # doctest: +SKIP
theta
>>> init_printing(order='lex') # doctest: +SKIP
>>> str(y + x + y**2 + x**2) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(order='grlex') # doctest: +SKIP
>>> str(y + x + y**2 + x**2) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(order='grevlex') # doctest: +SKIP
>>> str(y * x**2 + x * y**2) # doctest: +SKIP
x**2*y + x*y**2
>>> init_printing(order='old') # doctest: +SKIP
>>> str(x**2 + y**2 + x + y) # doctest: +SKIP
x**2 + x + y**2 + y
>>> init_printing(num_columns=10) # doctest: +SKIP
>>> x**2 + x + y**2 + y # doctest: +SKIP
x + y +
x**2 + y**2
"""
import sys
from sympy.printing.printer import Printer
if pretty_print:
if pretty_printer is not None:
stringify_func = pretty_printer
else:
from sympy.printing import pretty as stringify_func
else:
if str_printer is not None:
stringify_func = str_printer
else:
from sympy.printing import sstrrepr as stringify_func
# Even if ip is not passed, double check that not in IPython shell
in_ipython = False
if ip is None:
try:
ip = get_ipython()
except NameError:
pass
else:
in_ipython = (ip is not None)
if ip and not in_ipython:
in_ipython = _is_ipython(ip)
if in_ipython and pretty_print:
try:
import IPython
# IPython 1.0 deprecates the frontend module, so we import directly
# from the terminal module to prevent a deprecation message from being
# shown.
if V(IPython.__version__) >= '1.0':
from IPython.terminal.interactiveshell import TerminalInteractiveShell
else:
from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
from code import InteractiveConsole
except ImportError:
pass
else:
# This will be True if we are in the qtconsole or notebook
if not isinstance(ip, (InteractiveConsole, TerminalInteractiveShell)) \
and 'ipython-console' not in ''.join(sys.argv):
if use_unicode is None:
debug("init_printing: Setting use_unicode to True")
use_unicode = True
if use_latex is None:
debug("init_printing: Setting use_latex to True")
use_latex = True
if not NO_GLOBAL and not no_global:
Printer.set_global_settings(order=order, use_unicode=use_unicode,
wrap_line=wrap_line, num_columns=num_columns)
else:
_stringify_func = stringify_func
if pretty_print:
stringify_func = lambda expr: \
_stringify_func(expr, order=order,
use_unicode=use_unicode,
wrap_line=wrap_line,
num_columns=num_columns)
else:
stringify_func = lambda expr: _stringify_func(expr, order=order)
if in_ipython:
mode_in_settings = settings.pop("mode", None)
if mode_in_settings:
debug("init_printing: Mode is not able to be set due to internals"
"of IPython printing")
_init_ipython_printing(ip, stringify_func, use_latex, euler,
forecolor, backcolor, fontsize, latex_mode,
print_builtin, latex_printer, **settings)
else:
_init_python_printing(stringify_func, **settings)
|
b4d693f211d0cbd2ee921267b99799ea9f509a367281bd35bb53727c591ee95d
|
"""User-friendly public interface to polynomial functions. """
from __future__ import print_function, division
from sympy.core import (
S, Basic, Expr, I, Integer, Add, Mul, Dummy, Tuple
)
from sympy.core.mul import _keep_coeff
from sympy.core.symbol import Symbol
from sympy.core.basic import preorder_traversal
from sympy.core.relational import Relational
from sympy.core.sympify import sympify
from sympy.core.decorators import _sympifyit
from sympy.core.function import Derivative
from sympy.logic.boolalg import BooleanAtom
from sympy.polys.polyclasses import DMP
from sympy.polys.polyutils import (
basic_from_dict,
_sort_gens,
_unify_gens,
_dict_reorder,
_dict_from_expr,
_parallel_dict_from_expr,
)
from sympy.polys.rationaltools import together
from sympy.polys.rootisolation import dup_isolate_real_roots_list
from sympy.polys.groebnertools import groebner as _groebner
from sympy.polys.fglmtools import matrix_fglm
from sympy.polys.monomials import Monomial
from sympy.polys.orderings import monomial_key
from sympy.polys.polyerrors import (
OperationNotSupported, DomainError,
CoercionFailed, UnificationFailed,
GeneratorsNeeded, PolynomialError,
MultivariatePolynomialError,
ExactQuotientFailed,
PolificationFailed,
ComputationFailed,
GeneratorsError,
)
from sympy.utilities import group, sift, public, filldedent
import sympy.polys
import mpmath
from mpmath.libmp.libhyper import NoConvergence
from sympy.polys.domains import FF, QQ, ZZ
from sympy.polys.constructor import construct_domain
from sympy.polys import polyoptions as options
from sympy.core.compatibility import iterable, range, ordered
@public
class Poly(Expr):
"""
Generic class for representing and operating on polynomial expressions.
Subclasses Expr class.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
Create a univariate polynomial:
>>> Poly(x*(x**2 + x - 1)**2)
Poly(x**5 + 2*x**4 - x**3 - 2*x**2 + x, x, domain='ZZ')
Create a univariate polynomial with specific domain:
>>> from sympy import sqrt
>>> Poly(x**2 + 2*x + sqrt(3), domain='R')
Poly(1.0*x**2 + 2.0*x + 1.73205080756888, x, domain='RR')
Create a multivariate polynomial:
>>> Poly(y*x**2 + x*y + 1)
Poly(x**2*y + x*y + 1, x, y, domain='ZZ')
Create a univariate polynomial, where y is a constant:
>>> Poly(y*x**2 + x*y + 1,x)
Poly(y*x**2 + y*x + 1, x, domain='ZZ[y]')
You can evaluate the above polynomial as a function of y:
>>> Poly(y*x**2 + x*y + 1,x).eval(2)
6*y + 1
See Also
========
sympy.core.expr.Expr
"""
__slots__ = ['rep', 'gens']
is_commutative = True
is_Poly = True
_op_priority = 10.001
def __new__(cls, rep, *gens, **args):
"""Create a new polynomial instance out of something useful. """
opt = options.build_options(gens, args)
if 'order' in opt:
raise NotImplementedError("'order' keyword is not implemented yet")
if iterable(rep, exclude=str):
if isinstance(rep, dict):
return cls._from_dict(rep, opt)
else:
return cls._from_list(list(rep), opt)
else:
rep = sympify(rep)
if rep.is_Poly:
return cls._from_poly(rep, opt)
else:
return cls._from_expr(rep, opt)
@classmethod
def new(cls, rep, *gens):
"""Construct :class:`Poly` instance from raw representation. """
if not isinstance(rep, DMP):
raise PolynomialError(
"invalid polynomial representation: %s" % rep)
elif rep.lev != len(gens) - 1:
raise PolynomialError("invalid arguments: %s, %s" % (rep, gens))
obj = Basic.__new__(cls)
obj.rep = rep
obj.gens = gens
return obj
@classmethod
def from_dict(cls, rep, *gens, **args):
"""Construct a polynomial from a ``dict``. """
opt = options.build_options(gens, args)
return cls._from_dict(rep, opt)
@classmethod
def from_list(cls, rep, *gens, **args):
"""Construct a polynomial from a ``list``. """
opt = options.build_options(gens, args)
return cls._from_list(rep, opt)
@classmethod
def from_poly(cls, rep, *gens, **args):
"""Construct a polynomial from a polynomial. """
opt = options.build_options(gens, args)
return cls._from_poly(rep, opt)
@classmethod
def from_expr(cls, rep, *gens, **args):
"""Construct a polynomial from an expression. """
opt = options.build_options(gens, args)
return cls._from_expr(rep, opt)
@classmethod
def _from_dict(cls, rep, opt):
"""Construct a polynomial from a ``dict``. """
gens = opt.gens
if not gens:
raise GeneratorsNeeded(
"can't initialize from 'dict' without generators")
level = len(gens) - 1
domain = opt.domain
if domain is None:
domain, rep = construct_domain(rep, opt=opt)
else:
for monom, coeff in rep.items():
rep[monom] = domain.convert(coeff)
return cls.new(DMP.from_dict(rep, level, domain), *gens)
@classmethod
def _from_list(cls, rep, opt):
"""Construct a polynomial from a ``list``. """
gens = opt.gens
if not gens:
raise GeneratorsNeeded(
"can't initialize from 'list' without generators")
elif len(gens) != 1:
raise MultivariatePolynomialError(
"'list' representation not supported")
level = len(gens) - 1
domain = opt.domain
if domain is None:
domain, rep = construct_domain(rep, opt=opt)
else:
rep = list(map(domain.convert, rep))
return cls.new(DMP.from_list(rep, level, domain), *gens)
@classmethod
def _from_poly(cls, rep, opt):
"""Construct a polynomial from a polynomial. """
if cls != rep.__class__:
rep = cls.new(rep.rep, *rep.gens)
gens = opt.gens
field = opt.field
domain = opt.domain
if gens and rep.gens != gens:
if set(rep.gens) != set(gens):
return cls._from_expr(rep.as_expr(), opt)
else:
rep = rep.reorder(*gens)
if 'domain' in opt and domain:
rep = rep.set_domain(domain)
elif field is True:
rep = rep.to_field()
return rep
@classmethod
def _from_expr(cls, rep, opt):
"""Construct a polynomial from an expression. """
rep, opt = _dict_from_expr(rep, opt)
return cls._from_dict(rep, opt)
def _hashable_content(self):
"""Allow SymPy to hash Poly instances. """
return (self.rep, self.gens)
def __hash__(self):
return super(Poly, self).__hash__()
@property
def free_symbols(self):
"""
Free symbols of a polynomial expression.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> Poly(x**2 + 1).free_symbols
{x}
>>> Poly(x**2 + y).free_symbols
{x, y}
>>> Poly(x**2 + y, x).free_symbols
{x, y}
>>> Poly(x**2 + y, x, z).free_symbols
{x, y}
"""
symbols = set()
gens = self.gens
for i in range(len(gens)):
for monom in self.monoms():
if monom[i]:
symbols |= gens[i].free_symbols
break
return symbols | self.free_symbols_in_domain
@property
def free_symbols_in_domain(self):
"""
Free symbols of the domain of ``self``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 1).free_symbols_in_domain
set()
>>> Poly(x**2 + y).free_symbols_in_domain
set()
>>> Poly(x**2 + y, x).free_symbols_in_domain
{y}
"""
domain, symbols = self.rep.dom, set()
if domain.is_Composite:
for gen in domain.symbols:
symbols |= gen.free_symbols
elif domain.is_EX:
for coeff in self.coeffs():
symbols |= coeff.free_symbols
return symbols
@property
def args(self):
"""
Don't mess up with the core.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).args
(x**2 + 1,)
"""
return (self.as_expr(),)
@property
def gen(self):
"""
Return the principal generator.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).gen
x
"""
return self.gens[0]
@property
def domain(self):
"""Get the ground domain of ``self``. """
return self.get_domain()
@property
def zero(self):
"""Return zero polynomial with ``self``'s properties. """
return self.new(self.rep.zero(self.rep.lev, self.rep.dom), *self.gens)
@property
def one(self):
"""Return one polynomial with ``self``'s properties. """
return self.new(self.rep.one(self.rep.lev, self.rep.dom), *self.gens)
@property
def unit(self):
"""Return unit polynomial with ``self``'s properties. """
return self.new(self.rep.unit(self.rep.lev, self.rep.dom), *self.gens)
def unify(f, g):
"""
Make ``f`` and ``g`` belong to the same domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f, g = Poly(x/2 + 1), Poly(2*x + 1)
>>> f
Poly(1/2*x + 1, x, domain='QQ')
>>> g
Poly(2*x + 1, x, domain='ZZ')
>>> F, G = f.unify(g)
>>> F
Poly(1/2*x + 1, x, domain='QQ')
>>> G
Poly(2*x + 1, x, domain='QQ')
"""
_, per, F, G = f._unify(g)
return per(F), per(G)
def _unify(f, g):
g = sympify(g)
if not g.is_Poly:
try:
return f.rep.dom, f.per, f.rep, f.rep.per(f.rep.dom.from_sympy(g))
except CoercionFailed:
raise UnificationFailed("can't unify %s with %s" % (f, g))
if isinstance(f.rep, DMP) and isinstance(g.rep, DMP):
gens = _unify_gens(f.gens, g.gens)
dom, lev = f.rep.dom.unify(g.rep.dom, gens), len(gens) - 1
if f.gens != gens:
f_monoms, f_coeffs = _dict_reorder(
f.rep.to_dict(), f.gens, gens)
if f.rep.dom != dom:
f_coeffs = [dom.convert(c, f.rep.dom) for c in f_coeffs]
F = DMP(dict(list(zip(f_monoms, f_coeffs))), dom, lev)
else:
F = f.rep.convert(dom)
if g.gens != gens:
g_monoms, g_coeffs = _dict_reorder(
g.rep.to_dict(), g.gens, gens)
if g.rep.dom != dom:
g_coeffs = [dom.convert(c, g.rep.dom) for c in g_coeffs]
G = DMP(dict(list(zip(g_monoms, g_coeffs))), dom, lev)
else:
G = g.rep.convert(dom)
else:
raise UnificationFailed("can't unify %s with %s" % (f, g))
cls = f.__class__
def per(rep, dom=dom, gens=gens, remove=None):
if remove is not None:
gens = gens[:remove] + gens[remove + 1:]
if not gens:
return dom.to_sympy(rep)
return cls.new(rep, *gens)
return dom, per, F, G
def per(f, rep, gens=None, remove=None):
"""
Create a Poly out of the given representation.
Examples
========
>>> from sympy import Poly, ZZ
>>> from sympy.abc import x, y
>>> from sympy.polys.polyclasses import DMP
>>> a = Poly(x**2 + 1)
>>> a.per(DMP([ZZ(1), ZZ(1)], ZZ), gens=[y])
Poly(y + 1, y, domain='ZZ')
"""
if gens is None:
gens = f.gens
if remove is not None:
gens = gens[:remove] + gens[remove + 1:]
if not gens:
return f.rep.dom.to_sympy(rep)
return f.__class__.new(rep, *gens)
def set_domain(f, domain):
"""Set the ground domain of ``f``. """
opt = options.build_options(f.gens, {'domain': domain})
return f.per(f.rep.convert(opt.domain))
def get_domain(f):
"""Get the ground domain of ``f``. """
return f.rep.dom
def set_modulus(f, modulus):
"""
Set the modulus of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(5*x**2 + 2*x - 1, x).set_modulus(2)
Poly(x**2 + 1, x, modulus=2)
"""
modulus = options.Modulus.preprocess(modulus)
return f.set_domain(FF(modulus))
def get_modulus(f):
"""
Get the modulus of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, modulus=2).get_modulus()
2
"""
domain = f.get_domain()
if domain.is_FiniteField:
return Integer(domain.characteristic())
else:
raise PolynomialError("not a polynomial over a Galois field")
def _eval_subs(f, old, new):
"""Internal implementation of :func:`subs`. """
if old in f.gens:
if new.is_number:
return f.eval(old, new)
else:
try:
return f.replace(old, new)
except PolynomialError:
pass
return f.as_expr().subs(old, new)
def exclude(f):
"""
Remove unnecessary generators from ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import a, b, c, d, x
>>> Poly(a + x, a, b, c, d, x).exclude()
Poly(a + x, a, x, domain='ZZ')
"""
J, new = f.rep.exclude()
gens = []
for j in range(len(f.gens)):
if j not in J:
gens.append(f.gens[j])
return f.per(new, gens=gens)
def replace(f, x, y=None, *_ignore):
# XXX this does not match Basic's signature
"""
Replace ``x`` with ``y`` in generators list.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 1, x).replace(x, y)
Poly(y**2 + 1, y, domain='ZZ')
"""
if y is None:
if f.is_univariate:
x, y = f.gen, x
else:
raise PolynomialError(
"syntax supported only in univariate case")
if x == y or x not in f.gens:
return f
if x in f.gens and y not in f.gens:
dom = f.get_domain()
if not dom.is_Composite or y not in dom.symbols:
gens = list(f.gens)
gens[gens.index(x)] = y
return f.per(f.rep, gens=gens)
raise PolynomialError("can't replace %s with %s in %s" % (x, y, f))
def reorder(f, *gens, **args):
"""
Efficiently apply new order of generators.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + x*y**2, x, y).reorder(y, x)
Poly(y**2*x + x**2, y, x, domain='ZZ')
"""
opt = options.Options((), args)
if not gens:
gens = _sort_gens(f.gens, opt=opt)
elif set(f.gens) != set(gens):
raise PolynomialError(
"generators list can differ only up to order of elements")
rep = dict(list(zip(*_dict_reorder(f.rep.to_dict(), f.gens, gens))))
return f.per(DMP(rep, f.rep.dom, len(gens) - 1), gens=gens)
def ltrim(f, gen):
"""
Remove dummy generators from ``f`` that are to the left of
specified ``gen`` in the generators as ordered. When ``gen``
is an integer, it refers to the generator located at that
position within the tuple of generators of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> Poly(y**2 + y*z**2, x, y, z).ltrim(y)
Poly(y**2 + y*z**2, y, z, domain='ZZ')
>>> Poly(z, x, y, z).ltrim(-1)
Poly(z, z, domain='ZZ')
"""
rep = f.as_dict(native=True)
j = f._gen_to_level(gen)
terms = {}
for monom, coeff in rep.items():
if any(i for i in monom[:j]):
# some generator is used in the portion to be trimmed
raise PolynomialError("can't left trim %s" % f)
terms[monom[j:]] = coeff
gens = f.gens[j:]
return f.new(DMP.from_dict(terms, len(gens) - 1, f.rep.dom), *gens)
def has_only_gens(f, *gens):
"""
Return ``True`` if ``Poly(f, *gens)`` retains ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> Poly(x*y + 1, x, y, z).has_only_gens(x, y)
True
>>> Poly(x*y + z, x, y, z).has_only_gens(x, y)
False
"""
indices = set()
for gen in gens:
try:
index = f.gens.index(gen)
except ValueError:
raise GeneratorsError(
"%s doesn't have %s as generator" % (f, gen))
else:
indices.add(index)
for monom in f.monoms():
for i, elt in enumerate(monom):
if i not in indices and elt:
return False
return True
def to_ring(f):
"""
Make the ground domain a ring.
Examples
========
>>> from sympy import Poly, QQ
>>> from sympy.abc import x
>>> Poly(x**2 + 1, domain=QQ).to_ring()
Poly(x**2 + 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'to_ring'):
result = f.rep.to_ring()
else: # pragma: no cover
raise OperationNotSupported(f, 'to_ring')
return f.per(result)
def to_field(f):
"""
Make the ground domain a field.
Examples
========
>>> from sympy import Poly, ZZ
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x, domain=ZZ).to_field()
Poly(x**2 + 1, x, domain='QQ')
"""
if hasattr(f.rep, 'to_field'):
result = f.rep.to_field()
else: # pragma: no cover
raise OperationNotSupported(f, 'to_field')
return f.per(result)
def to_exact(f):
"""
Make the ground domain exact.
Examples
========
>>> from sympy import Poly, RR
>>> from sympy.abc import x
>>> Poly(x**2 + 1.0, x, domain=RR).to_exact()
Poly(x**2 + 1, x, domain='QQ')
"""
if hasattr(f.rep, 'to_exact'):
result = f.rep.to_exact()
else: # pragma: no cover
raise OperationNotSupported(f, 'to_exact')
return f.per(result)
def retract(f, field=None):
"""
Recalculate the ground domain of a polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = Poly(x**2 + 1, x, domain='QQ[y]')
>>> f
Poly(x**2 + 1, x, domain='QQ[y]')
>>> f.retract()
Poly(x**2 + 1, x, domain='ZZ')
>>> f.retract(field=True)
Poly(x**2 + 1, x, domain='QQ')
"""
dom, rep = construct_domain(f.as_dict(zero=True),
field=field, composite=f.domain.is_Composite or None)
return f.from_dict(rep, f.gens, domain=dom)
def slice(f, x, m, n=None):
"""Take a continuous subsequence of terms of ``f``. """
if n is None:
j, m, n = 0, x, m
else:
j = f._gen_to_level(x)
m, n = int(m), int(n)
if hasattr(f.rep, 'slice'):
result = f.rep.slice(m, n, j)
else: # pragma: no cover
raise OperationNotSupported(f, 'slice')
return f.per(result)
def coeffs(f, order=None):
"""
Returns all non-zero coefficients from ``f`` in lex order.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x + 3, x).coeffs()
[1, 2, 3]
See Also
========
all_coeffs
coeff_monomial
nth
"""
return [f.rep.dom.to_sympy(c) for c in f.rep.coeffs(order=order)]
def monoms(f, order=None):
"""
Returns all non-zero monomials from ``f`` in lex order.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 2*x*y**2 + x*y + 3*y, x, y).monoms()
[(2, 0), (1, 2), (1, 1), (0, 1)]
See Also
========
all_monoms
"""
return f.rep.monoms(order=order)
def terms(f, order=None):
"""
Returns all non-zero terms from ``f`` in lex order.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 2*x*y**2 + x*y + 3*y, x, y).terms()
[((2, 0), 1), ((1, 2), 2), ((1, 1), 1), ((0, 1), 3)]
See Also
========
all_terms
"""
return [(m, f.rep.dom.to_sympy(c)) for m, c in f.rep.terms(order=order)]
def all_coeffs(f):
"""
Returns all coefficients from a univariate polynomial ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x - 1, x).all_coeffs()
[1, 0, 2, -1]
"""
return [f.rep.dom.to_sympy(c) for c in f.rep.all_coeffs()]
def all_monoms(f):
"""
Returns all monomials from a univariate polynomial ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x - 1, x).all_monoms()
[(3,), (2,), (1,), (0,)]
See Also
========
all_terms
"""
return f.rep.all_monoms()
def all_terms(f):
"""
Returns all terms from a univariate polynomial ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x - 1, x).all_terms()
[((3,), 1), ((2,), 0), ((1,), 2), ((0,), -1)]
"""
return [(m, f.rep.dom.to_sympy(c)) for m, c in f.rep.all_terms()]
def termwise(f, func, *gens, **args):
"""
Apply a function to all terms of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> def func(k, coeff):
... k = k[0]
... return coeff//10**(2-k)
>>> Poly(x**2 + 20*x + 400).termwise(func)
Poly(x**2 + 2*x + 4, x, domain='ZZ')
"""
terms = {}
for monom, coeff in f.terms():
result = func(monom, coeff)
if isinstance(result, tuple):
monom, coeff = result
else:
coeff = result
if coeff:
if monom not in terms:
terms[monom] = coeff
else:
raise PolynomialError(
"%s monomial was generated twice" % monom)
return f.from_dict(terms, *(gens or f.gens), **args)
def length(f):
"""
Returns the number of non-zero terms in ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 2*x - 1).length()
3
"""
return len(f.as_dict())
def as_dict(f, native=False, zero=False):
"""
Switch to a ``dict`` representation.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 2*x*y**2 - y, x, y).as_dict()
{(0, 1): -1, (1, 2): 2, (2, 0): 1}
"""
if native:
return f.rep.to_dict(zero=zero)
else:
return f.rep.to_sympy_dict(zero=zero)
def as_list(f, native=False):
"""Switch to a ``list`` representation. """
if native:
return f.rep.to_list()
else:
return f.rep.to_sympy_list()
def as_expr(f, *gens):
"""
Convert a Poly instance to an Expr instance.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = Poly(x**2 + 2*x*y**2 - y, x, y)
>>> f.as_expr()
x**2 + 2*x*y**2 - y
>>> f.as_expr({x: 5})
10*y**2 - y + 25
>>> f.as_expr(5, 6)
379
"""
if not gens:
gens = f.gens
elif len(gens) == 1 and isinstance(gens[0], dict):
mapping = gens[0]
gens = list(f.gens)
for gen, value in mapping.items():
try:
index = gens.index(gen)
except ValueError:
raise GeneratorsError(
"%s doesn't have %s as generator" % (f, gen))
else:
gens[index] = value
return basic_from_dict(f.rep.to_sympy_dict(), *gens)
def lift(f):
"""
Convert algebraic coefficients to rationals.
Examples
========
>>> from sympy import Poly, I
>>> from sympy.abc import x
>>> Poly(x**2 + I*x + 1, x, extension=I).lift()
Poly(x**4 + 3*x**2 + 1, x, domain='QQ')
"""
if hasattr(f.rep, 'lift'):
result = f.rep.lift()
else: # pragma: no cover
raise OperationNotSupported(f, 'lift')
return f.per(result)
def deflate(f):
"""
Reduce degree of ``f`` by mapping ``x_i**m`` to ``y_i``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**6*y**2 + x**3 + 1, x, y).deflate()
((3, 2), Poly(x**2*y + x + 1, x, y, domain='ZZ'))
"""
if hasattr(f.rep, 'deflate'):
J, result = f.rep.deflate()
else: # pragma: no cover
raise OperationNotSupported(f, 'deflate')
return J, f.per(result)
def inject(f, front=False):
"""
Inject ground domain generators into ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = Poly(x**2*y + x*y**3 + x*y + 1, x)
>>> f.inject()
Poly(x**2*y + x*y**3 + x*y + 1, x, y, domain='ZZ')
>>> f.inject(front=True)
Poly(y**3*x + y*x**2 + y*x + 1, y, x, domain='ZZ')
"""
dom = f.rep.dom
if dom.is_Numerical:
return f
elif not dom.is_Poly:
raise DomainError("can't inject generators over %s" % dom)
if hasattr(f.rep, 'inject'):
result = f.rep.inject(front=front)
else: # pragma: no cover
raise OperationNotSupported(f, 'inject')
if front:
gens = dom.symbols + f.gens
else:
gens = f.gens + dom.symbols
return f.new(result, *gens)
def eject(f, *gens):
"""
Eject selected generators into the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = Poly(x**2*y + x*y**3 + x*y + 1, x, y)
>>> f.eject(x)
Poly(x*y**3 + (x**2 + x)*y + 1, y, domain='ZZ[x]')
>>> f.eject(y)
Poly(y*x**2 + (y**3 + y)*x + 1, x, domain='ZZ[y]')
"""
dom = f.rep.dom
if not dom.is_Numerical:
raise DomainError("can't eject generators over %s" % dom)
n, k = len(f.gens), len(gens)
if f.gens[:k] == gens:
_gens, front = f.gens[k:], True
elif f.gens[-k:] == gens:
_gens, front = f.gens[:-k], False
else:
raise NotImplementedError(
"can only eject front or back generators")
dom = dom.inject(*gens)
if hasattr(f.rep, 'eject'):
result = f.rep.eject(dom, front=front)
else: # pragma: no cover
raise OperationNotSupported(f, 'eject')
return f.new(result, *_gens)
def terms_gcd(f):
"""
Remove GCD of terms from the polynomial ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**6*y**2 + x**3*y, x, y).terms_gcd()
((3, 1), Poly(x**3*y + 1, x, y, domain='ZZ'))
"""
if hasattr(f.rep, 'terms_gcd'):
J, result = f.rep.terms_gcd()
else: # pragma: no cover
raise OperationNotSupported(f, 'terms_gcd')
return J, f.per(result)
def add_ground(f, coeff):
"""
Add an element of the ground domain to ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x + 1).add_ground(2)
Poly(x + 3, x, domain='ZZ')
"""
if hasattr(f.rep, 'add_ground'):
result = f.rep.add_ground(coeff)
else: # pragma: no cover
raise OperationNotSupported(f, 'add_ground')
return f.per(result)
def sub_ground(f, coeff):
"""
Subtract an element of the ground domain from ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x + 1).sub_ground(2)
Poly(x - 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'sub_ground'):
result = f.rep.sub_ground(coeff)
else: # pragma: no cover
raise OperationNotSupported(f, 'sub_ground')
return f.per(result)
def mul_ground(f, coeff):
"""
Multiply ``f`` by a an element of the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x + 1).mul_ground(2)
Poly(2*x + 2, x, domain='ZZ')
"""
if hasattr(f.rep, 'mul_ground'):
result = f.rep.mul_ground(coeff)
else: # pragma: no cover
raise OperationNotSupported(f, 'mul_ground')
return f.per(result)
def quo_ground(f, coeff):
"""
Quotient of ``f`` by a an element of the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x + 4).quo_ground(2)
Poly(x + 2, x, domain='ZZ')
>>> Poly(2*x + 3).quo_ground(2)
Poly(x + 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'quo_ground'):
result = f.rep.quo_ground(coeff)
else: # pragma: no cover
raise OperationNotSupported(f, 'quo_ground')
return f.per(result)
def exquo_ground(f, coeff):
"""
Exact quotient of ``f`` by a an element of the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x + 4).exquo_ground(2)
Poly(x + 2, x, domain='ZZ')
>>> Poly(2*x + 3).exquo_ground(2)
Traceback (most recent call last):
...
ExactQuotientFailed: 2 does not divide 3 in ZZ
"""
if hasattr(f.rep, 'exquo_ground'):
result = f.rep.exquo_ground(coeff)
else: # pragma: no cover
raise OperationNotSupported(f, 'exquo_ground')
return f.per(result)
def abs(f):
"""
Make all coefficients in ``f`` positive.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).abs()
Poly(x**2 + 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'abs'):
result = f.rep.abs()
else: # pragma: no cover
raise OperationNotSupported(f, 'abs')
return f.per(result)
def neg(f):
"""
Negate all coefficients in ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).neg()
Poly(-x**2 + 1, x, domain='ZZ')
>>> -Poly(x**2 - 1, x)
Poly(-x**2 + 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'neg'):
result = f.rep.neg()
else: # pragma: no cover
raise OperationNotSupported(f, 'neg')
return f.per(result)
def add(f, g):
"""
Add two polynomials ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).add(Poly(x - 2, x))
Poly(x**2 + x - 1, x, domain='ZZ')
>>> Poly(x**2 + 1, x) + Poly(x - 2, x)
Poly(x**2 + x - 1, x, domain='ZZ')
"""
g = sympify(g)
if not g.is_Poly:
return f.add_ground(g)
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'add'):
result = F.add(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'add')
return per(result)
def sub(f, g):
"""
Subtract two polynomials ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).sub(Poly(x - 2, x))
Poly(x**2 - x + 3, x, domain='ZZ')
>>> Poly(x**2 + 1, x) - Poly(x - 2, x)
Poly(x**2 - x + 3, x, domain='ZZ')
"""
g = sympify(g)
if not g.is_Poly:
return f.sub_ground(g)
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'sub'):
result = F.sub(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'sub')
return per(result)
def mul(f, g):
"""
Multiply two polynomials ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).mul(Poly(x - 2, x))
Poly(x**3 - 2*x**2 + x - 2, x, domain='ZZ')
>>> Poly(x**2 + 1, x)*Poly(x - 2, x)
Poly(x**3 - 2*x**2 + x - 2, x, domain='ZZ')
"""
g = sympify(g)
if not g.is_Poly:
return f.mul_ground(g)
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'mul'):
result = F.mul(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'mul')
return per(result)
def sqr(f):
"""
Square a polynomial ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x - 2, x).sqr()
Poly(x**2 - 4*x + 4, x, domain='ZZ')
>>> Poly(x - 2, x)**2
Poly(x**2 - 4*x + 4, x, domain='ZZ')
"""
if hasattr(f.rep, 'sqr'):
result = f.rep.sqr()
else: # pragma: no cover
raise OperationNotSupported(f, 'sqr')
return f.per(result)
def pow(f, n):
"""
Raise ``f`` to a non-negative power ``n``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x - 2, x).pow(3)
Poly(x**3 - 6*x**2 + 12*x - 8, x, domain='ZZ')
>>> Poly(x - 2, x)**3
Poly(x**3 - 6*x**2 + 12*x - 8, x, domain='ZZ')
"""
n = int(n)
if hasattr(f.rep, 'pow'):
result = f.rep.pow(n)
else: # pragma: no cover
raise OperationNotSupported(f, 'pow')
return f.per(result)
def pdiv(f, g):
"""
Polynomial pseudo-division of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).pdiv(Poly(2*x - 4, x))
(Poly(2*x + 4, x, domain='ZZ'), Poly(20, x, domain='ZZ'))
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'pdiv'):
q, r = F.pdiv(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'pdiv')
return per(q), per(r)
def prem(f, g):
"""
Polynomial pseudo-remainder of ``f`` by ``g``.
Caveat: The function prem(f, g, x) can be safely used to compute
in Z[x] _only_ subresultant polynomial remainder sequences (prs's).
To safely compute Euclidean and Sturmian prs's in Z[x]
employ anyone of the corresponding functions found in
the module sympy.polys.subresultants_qq_zz. The functions
in the module with suffix _pg compute prs's in Z[x] employing
rem(f, g, x), whereas the functions with suffix _amv
compute prs's in Z[x] employing rem_z(f, g, x).
The function rem_z(f, g, x) differs from prem(f, g, x) in that
to compute the remainder polynomials in Z[x] it premultiplies
the divident times the absolute value of the leading coefficient
of the divisor raised to the power degree(f, x) - degree(g, x) + 1.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).prem(Poly(2*x - 4, x))
Poly(20, x, domain='ZZ')
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'prem'):
result = F.prem(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'prem')
return per(result)
def pquo(f, g):
"""
Polynomial pseudo-quotient of ``f`` by ``g``.
See the Caveat note in the function prem(f, g).
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).pquo(Poly(2*x - 4, x))
Poly(2*x + 4, x, domain='ZZ')
>>> Poly(x**2 - 1, x).pquo(Poly(2*x - 2, x))
Poly(2*x + 2, x, domain='ZZ')
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'pquo'):
result = F.pquo(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'pquo')
return per(result)
def pexquo(f, g):
"""
Polynomial exact pseudo-quotient of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).pexquo(Poly(2*x - 2, x))
Poly(2*x + 2, x, domain='ZZ')
>>> Poly(x**2 + 1, x).pexquo(Poly(2*x - 4, x))
Traceback (most recent call last):
...
ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'pexquo'):
try:
result = F.pexquo(G)
except ExactQuotientFailed as exc:
raise exc.new(f.as_expr(), g.as_expr())
else: # pragma: no cover
raise OperationNotSupported(f, 'pexquo')
return per(result)
def div(f, g, auto=True):
"""
Polynomial division with remainder of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).div(Poly(2*x - 4, x))
(Poly(1/2*x + 1, x, domain='QQ'), Poly(5, x, domain='QQ'))
>>> Poly(x**2 + 1, x).div(Poly(2*x - 4, x), auto=False)
(Poly(0, x, domain='ZZ'), Poly(x**2 + 1, x, domain='ZZ'))
"""
dom, per, F, G = f._unify(g)
retract = False
if auto and dom.is_Ring and not dom.is_Field:
F, G = F.to_field(), G.to_field()
retract = True
if hasattr(f.rep, 'div'):
q, r = F.div(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'div')
if retract:
try:
Q, R = q.to_ring(), r.to_ring()
except CoercionFailed:
pass
else:
q, r = Q, R
return per(q), per(r)
def rem(f, g, auto=True):
"""
Computes the polynomial remainder of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).rem(Poly(2*x - 4, x))
Poly(5, x, domain='ZZ')
>>> Poly(x**2 + 1, x).rem(Poly(2*x - 4, x), auto=False)
Poly(x**2 + 1, x, domain='ZZ')
"""
dom, per, F, G = f._unify(g)
retract = False
if auto and dom.is_Ring and not dom.is_Field:
F, G = F.to_field(), G.to_field()
retract = True
if hasattr(f.rep, 'rem'):
r = F.rem(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'rem')
if retract:
try:
r = r.to_ring()
except CoercionFailed:
pass
return per(r)
def quo(f, g, auto=True):
"""
Computes polynomial quotient of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).quo(Poly(2*x - 4, x))
Poly(1/2*x + 1, x, domain='QQ')
>>> Poly(x**2 - 1, x).quo(Poly(x - 1, x))
Poly(x + 1, x, domain='ZZ')
"""
dom, per, F, G = f._unify(g)
retract = False
if auto and dom.is_Ring and not dom.is_Field:
F, G = F.to_field(), G.to_field()
retract = True
if hasattr(f.rep, 'quo'):
q = F.quo(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'quo')
if retract:
try:
q = q.to_ring()
except CoercionFailed:
pass
return per(q)
def exquo(f, g, auto=True):
"""
Computes polynomial exact quotient of ``f`` by ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).exquo(Poly(x - 1, x))
Poly(x + 1, x, domain='ZZ')
>>> Poly(x**2 + 1, x).exquo(Poly(2*x - 4, x))
Traceback (most recent call last):
...
ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1
"""
dom, per, F, G = f._unify(g)
retract = False
if auto and dom.is_Ring and not dom.is_Field:
F, G = F.to_field(), G.to_field()
retract = True
if hasattr(f.rep, 'exquo'):
try:
q = F.exquo(G)
except ExactQuotientFailed as exc:
raise exc.new(f.as_expr(), g.as_expr())
else: # pragma: no cover
raise OperationNotSupported(f, 'exquo')
if retract:
try:
q = q.to_ring()
except CoercionFailed:
pass
return per(q)
def _gen_to_level(f, gen):
"""Returns level associated with the given generator. """
if isinstance(gen, int):
length = len(f.gens)
if -length <= gen < length:
if gen < 0:
return length + gen
else:
return gen
else:
raise PolynomialError("-%s <= gen < %s expected, got %s" %
(length, length, gen))
else:
try:
return f.gens.index(sympify(gen))
except ValueError:
raise PolynomialError(
"a valid generator expected, got %s" % gen)
def degree(f, gen=0):
"""
Returns degree of ``f`` in ``x_j``.
The degree of 0 is negative infinity.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + y*x + 1, x, y).degree()
2
>>> Poly(x**2 + y*x + y, x, y).degree(y)
1
>>> Poly(0, x).degree()
-oo
"""
j = f._gen_to_level(gen)
if hasattr(f.rep, 'degree'):
return f.rep.degree(j)
else: # pragma: no cover
raise OperationNotSupported(f, 'degree')
def degree_list(f):
"""
Returns a list of degrees of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + y*x + 1, x, y).degree_list()
(2, 1)
"""
if hasattr(f.rep, 'degree_list'):
return f.rep.degree_list()
else: # pragma: no cover
raise OperationNotSupported(f, 'degree_list')
def total_degree(f):
"""
Returns the total degree of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + y*x + 1, x, y).total_degree()
2
>>> Poly(x + y**5, x, y).total_degree()
5
"""
if hasattr(f.rep, 'total_degree'):
return f.rep.total_degree()
else: # pragma: no cover
raise OperationNotSupported(f, 'total_degree')
def homogenize(f, s):
"""
Returns the homogeneous polynomial of ``f``.
A homogeneous polynomial is a polynomial whose all monomials with
non-zero coefficients have the same total degree. If you only
want to check if a polynomial is homogeneous, then use
:func:`Poly.is_homogeneous`. If you want not only to check if a
polynomial is homogeneous but also compute its homogeneous order,
then use :func:`Poly.homogeneous_order`.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> f = Poly(x**5 + 2*x**2*y**2 + 9*x*y**3)
>>> f.homogenize(z)
Poly(x**5 + 2*x**2*y**2*z + 9*x*y**3*z, x, y, z, domain='ZZ')
"""
if not isinstance(s, Symbol):
raise TypeError("``Symbol`` expected, got %s" % type(s))
if s in f.gens:
i = f.gens.index(s)
gens = f.gens
else:
i = len(f.gens)
gens = f.gens + (s,)
if hasattr(f.rep, 'homogenize'):
return f.per(f.rep.homogenize(i), gens=gens)
raise OperationNotSupported(f, 'homogeneous_order')
def homogeneous_order(f):
"""
Returns the homogeneous order of ``f``.
A homogeneous polynomial is a polynomial whose all monomials with
non-zero coefficients have the same total degree. This degree is
the homogeneous order of ``f``. If you only want to check if a
polynomial is homogeneous, then use :func:`Poly.is_homogeneous`.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = Poly(x**5 + 2*x**3*y**2 + 9*x*y**4)
>>> f.homogeneous_order()
5
"""
if hasattr(f.rep, 'homogeneous_order'):
return f.rep.homogeneous_order()
else: # pragma: no cover
raise OperationNotSupported(f, 'homogeneous_order')
def LC(f, order=None):
"""
Returns the leading coefficient of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(4*x**3 + 2*x**2 + 3*x, x).LC()
4
"""
if order is not None:
return f.coeffs(order)[0]
if hasattr(f.rep, 'LC'):
result = f.rep.LC()
else: # pragma: no cover
raise OperationNotSupported(f, 'LC')
return f.rep.dom.to_sympy(result)
def TC(f):
"""
Returns the trailing coefficient of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x**2 + 3*x, x).TC()
0
"""
if hasattr(f.rep, 'TC'):
result = f.rep.TC()
else: # pragma: no cover
raise OperationNotSupported(f, 'TC')
return f.rep.dom.to_sympy(result)
def EC(f, order=None):
"""
Returns the last non-zero coefficient of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 + 2*x**2 + 3*x, x).EC()
3
"""
if hasattr(f.rep, 'coeffs'):
return f.coeffs(order)[-1]
else: # pragma: no cover
raise OperationNotSupported(f, 'EC')
def coeff_monomial(f, monom):
"""
Returns the coefficient of ``monom`` in ``f`` if there, else None.
Examples
========
>>> from sympy import Poly, exp
>>> from sympy.abc import x, y
>>> p = Poly(24*x*y*exp(8) + 23*x, x, y)
>>> p.coeff_monomial(x)
23
>>> p.coeff_monomial(y)
0
>>> p.coeff_monomial(x*y)
24*exp(8)
Note that ``Expr.coeff()`` behaves differently, collecting terms
if possible; the Poly must be converted to an Expr to use that
method, however:
>>> p.as_expr().coeff(x)
24*y*exp(8) + 23
>>> p.as_expr().coeff(y)
24*x*exp(8)
>>> p.as_expr().coeff(x*y)
24*exp(8)
See Also
========
nth: more efficient query using exponents of the monomial's generators
"""
return f.nth(*Monomial(monom, f.gens).exponents)
def nth(f, *N):
"""
Returns the ``n``-th coefficient of ``f`` where ``N`` are the
exponents of the generators in the term of interest.
Examples
========
>>> from sympy import Poly, sqrt
>>> from sympy.abc import x, y
>>> Poly(x**3 + 2*x**2 + 3*x, x).nth(2)
2
>>> Poly(x**3 + 2*x*y**2 + y**2, x, y).nth(1, 2)
2
>>> Poly(4*sqrt(x)*y)
Poly(4*y*(sqrt(x)), y, sqrt(x), domain='ZZ')
>>> _.nth(1, 1)
4
See Also
========
coeff_monomial
"""
if hasattr(f.rep, 'nth'):
if len(N) != len(f.gens):
raise ValueError('exponent of each generator must be specified')
result = f.rep.nth(*list(map(int, N)))
else: # pragma: no cover
raise OperationNotSupported(f, 'nth')
return f.rep.dom.to_sympy(result)
def coeff(f, x, n=1, right=False):
# the semantics of coeff_monomial and Expr.coeff are different;
# if someone is working with a Poly, they should be aware of the
# differences and chose the method best suited for the query.
# Alternatively, a pure-polys method could be written here but
# at this time the ``right`` keyword would be ignored because Poly
# doesn't work with non-commutatives.
raise NotImplementedError(
'Either convert to Expr with `as_expr` method '
'to use Expr\'s coeff method or else use the '
'`coeff_monomial` method of Polys.')
def LM(f, order=None):
"""
Returns the leading monomial of ``f``.
The Leading monomial signifies the monomial having
the highest power of the principal generator in the
expression f.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).LM()
x**2*y**0
"""
return Monomial(f.monoms(order)[0], f.gens)
def EM(f, order=None):
"""
Returns the last non-zero monomial of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).EM()
x**0*y**1
"""
return Monomial(f.monoms(order)[-1], f.gens)
def LT(f, order=None):
"""
Returns the leading term of ``f``.
The Leading term signifies the term having
the highest power of the principal generator in the
expression f along with its coefficient.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).LT()
(x**2*y**0, 4)
"""
monom, coeff = f.terms(order)[0]
return Monomial(monom, f.gens), coeff
def ET(f, order=None):
"""
Returns the last non-zero term of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).ET()
(x**0*y**1, 3)
"""
monom, coeff = f.terms(order)[-1]
return Monomial(monom, f.gens), coeff
def max_norm(f):
"""
Returns maximum norm of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(-x**2 + 2*x - 3, x).max_norm()
3
"""
if hasattr(f.rep, 'max_norm'):
result = f.rep.max_norm()
else: # pragma: no cover
raise OperationNotSupported(f, 'max_norm')
return f.rep.dom.to_sympy(result)
def l1_norm(f):
"""
Returns l1 norm of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(-x**2 + 2*x - 3, x).l1_norm()
6
"""
if hasattr(f.rep, 'l1_norm'):
result = f.rep.l1_norm()
else: # pragma: no cover
raise OperationNotSupported(f, 'l1_norm')
return f.rep.dom.to_sympy(result)
def clear_denoms(self, convert=False):
"""
Clear denominators, but keep the ground domain.
Examples
========
>>> from sympy import Poly, S, QQ
>>> from sympy.abc import x
>>> f = Poly(x/2 + S(1)/3, x, domain=QQ)
>>> f.clear_denoms()
(6, Poly(3*x + 2, x, domain='QQ'))
>>> f.clear_denoms(convert=True)
(6, Poly(3*x + 2, x, domain='ZZ'))
"""
f = self
if not f.rep.dom.is_Field:
return S.One, f
dom = f.get_domain()
if dom.has_assoc_Ring:
dom = f.rep.dom.get_ring()
if hasattr(f.rep, 'clear_denoms'):
coeff, result = f.rep.clear_denoms()
else: # pragma: no cover
raise OperationNotSupported(f, 'clear_denoms')
coeff, f = dom.to_sympy(coeff), f.per(result)
if not convert or not dom.has_assoc_Ring:
return coeff, f
else:
return coeff, f.to_ring()
def rat_clear_denoms(self, g):
"""
Clear denominators in a rational function ``f/g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = Poly(x**2/y + 1, x)
>>> g = Poly(x**3 + y, x)
>>> p, q = f.rat_clear_denoms(g)
>>> p
Poly(x**2 + y, x, domain='ZZ[y]')
>>> q
Poly(y*x**3 + y**2, x, domain='ZZ[y]')
"""
f = self
dom, per, f, g = f._unify(g)
f = per(f)
g = per(g)
if not (dom.is_Field and dom.has_assoc_Ring):
return f, g
a, f = f.clear_denoms(convert=True)
b, g = g.clear_denoms(convert=True)
f = f.mul_ground(b)
g = g.mul_ground(a)
return f, g
def integrate(self, *specs, **args):
"""
Computes indefinite integral of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 2*x + 1, x).integrate()
Poly(1/3*x**3 + x**2 + x, x, domain='QQ')
>>> Poly(x*y**2 + x, x, y).integrate((0, 1), (1, 0))
Poly(1/2*x**2*y**2 + 1/2*x**2, x, y, domain='QQ')
"""
f = self
if args.get('auto', True) and f.rep.dom.is_Ring:
f = f.to_field()
if hasattr(f.rep, 'integrate'):
if not specs:
return f.per(f.rep.integrate(m=1))
rep = f.rep
for spec in specs:
if type(spec) is tuple:
gen, m = spec
else:
gen, m = spec, 1
rep = rep.integrate(int(m), f._gen_to_level(gen))
return f.per(rep)
else: # pragma: no cover
raise OperationNotSupported(f, 'integrate')
def diff(f, *specs, **kwargs):
"""
Computes partial derivative of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + 2*x + 1, x).diff()
Poly(2*x + 2, x, domain='ZZ')
>>> Poly(x*y**2 + x, x, y).diff((0, 0), (1, 1))
Poly(2*x*y, x, y, domain='ZZ')
"""
if not kwargs.get('evaluate', True):
return Derivative(f, *specs, **kwargs)
if hasattr(f.rep, 'diff'):
if not specs:
return f.per(f.rep.diff(m=1))
rep = f.rep
for spec in specs:
if type(spec) is tuple:
gen, m = spec
else:
gen, m = spec, 1
rep = rep.diff(int(m), f._gen_to_level(gen))
return f.per(rep)
else: # pragma: no cover
raise OperationNotSupported(f, 'diff')
_eval_derivative = diff
def eval(self, x, a=None, auto=True):
"""
Evaluate ``f`` at ``a`` in the given variable.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> Poly(x**2 + 2*x + 3, x).eval(2)
11
>>> Poly(2*x*y + 3*x + y + 2, x, y).eval(x, 2)
Poly(5*y + 8, y, domain='ZZ')
>>> f = Poly(2*x*y + 3*x + y + 2*z, x, y, z)
>>> f.eval({x: 2})
Poly(5*y + 2*z + 6, y, z, domain='ZZ')
>>> f.eval({x: 2, y: 5})
Poly(2*z + 31, z, domain='ZZ')
>>> f.eval({x: 2, y: 5, z: 7})
45
>>> f.eval((2, 5))
Poly(2*z + 31, z, domain='ZZ')
>>> f(2, 5)
Poly(2*z + 31, z, domain='ZZ')
"""
f = self
if a is None:
if isinstance(x, dict):
mapping = x
for gen, value in mapping.items():
f = f.eval(gen, value)
return f
elif isinstance(x, (tuple, list)):
values = x
if len(values) > len(f.gens):
raise ValueError("too many values provided")
for gen, value in zip(f.gens, values):
f = f.eval(gen, value)
return f
else:
j, a = 0, x
else:
j = f._gen_to_level(x)
if not hasattr(f.rep, 'eval'): # pragma: no cover
raise OperationNotSupported(f, 'eval')
try:
result = f.rep.eval(a, j)
except CoercionFailed:
if not auto:
raise DomainError("can't evaluate at %s in %s" % (a, f.rep.dom))
else:
a_domain, [a] = construct_domain([a])
new_domain = f.get_domain().unify_with_symbols(a_domain, f.gens)
f = f.set_domain(new_domain)
a = new_domain.convert(a, a_domain)
result = f.rep.eval(a, j)
return f.per(result, remove=j)
def __call__(f, *values):
"""
Evaluate ``f`` at the give values.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y, z
>>> f = Poly(2*x*y + 3*x + y + 2*z, x, y, z)
>>> f(2)
Poly(5*y + 2*z + 6, y, z, domain='ZZ')
>>> f(2, 5)
Poly(2*z + 31, z, domain='ZZ')
>>> f(2, 5, 7)
45
"""
return f.eval(values)
def half_gcdex(f, g, auto=True):
"""
Half extended Euclidean algorithm of ``f`` and ``g``.
Returns ``(s, h)`` such that ``h = gcd(f, g)`` and ``s*f = h (mod g)``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15
>>> g = x**3 + x**2 - 4*x - 4
>>> Poly(f).half_gcdex(Poly(g))
(Poly(-1/5*x + 3/5, x, domain='QQ'), Poly(x + 1, x, domain='QQ'))
"""
dom, per, F, G = f._unify(g)
if auto and dom.is_Ring:
F, G = F.to_field(), G.to_field()
if hasattr(f.rep, 'half_gcdex'):
s, h = F.half_gcdex(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'half_gcdex')
return per(s), per(h)
def gcdex(f, g, auto=True):
"""
Extended Euclidean algorithm of ``f`` and ``g``.
Returns ``(s, t, h)`` such that ``h = gcd(f, g)`` and ``s*f + t*g = h``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15
>>> g = x**3 + x**2 - 4*x - 4
>>> Poly(f).gcdex(Poly(g))
(Poly(-1/5*x + 3/5, x, domain='QQ'),
Poly(1/5*x**2 - 6/5*x + 2, x, domain='QQ'),
Poly(x + 1, x, domain='QQ'))
"""
dom, per, F, G = f._unify(g)
if auto and dom.is_Ring:
F, G = F.to_field(), G.to_field()
if hasattr(f.rep, 'gcdex'):
s, t, h = F.gcdex(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'gcdex')
return per(s), per(t), per(h)
def invert(f, g, auto=True):
"""
Invert ``f`` modulo ``g`` when possible.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).invert(Poly(2*x - 1, x))
Poly(-4/3, x, domain='QQ')
>>> Poly(x**2 - 1, x).invert(Poly(x - 1, x))
Traceback (most recent call last):
...
NotInvertible: zero divisor
"""
dom, per, F, G = f._unify(g)
if auto and dom.is_Ring:
F, G = F.to_field(), G.to_field()
if hasattr(f.rep, 'invert'):
result = F.invert(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'invert')
return per(result)
def revert(f, n):
"""
Compute ``f**(-1)`` mod ``x**n``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(1, x).revert(2)
Poly(1, x, domain='ZZ')
>>> Poly(1 + x, x).revert(1)
Poly(1, x, domain='ZZ')
>>> Poly(x**2 - 1, x).revert(1)
Traceback (most recent call last):
...
NotReversible: only unity is reversible in a ring
>>> Poly(1/x, x).revert(1)
Traceback (most recent call last):
...
PolynomialError: 1/x contains an element of the generators set
"""
if hasattr(f.rep, 'revert'):
result = f.rep.revert(int(n))
else: # pragma: no cover
raise OperationNotSupported(f, 'revert')
return f.per(result)
def subresultants(f, g):
"""
Computes the subresultant PRS of ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 1, x).subresultants(Poly(x**2 - 1, x))
[Poly(x**2 + 1, x, domain='ZZ'),
Poly(x**2 - 1, x, domain='ZZ'),
Poly(-2, x, domain='ZZ')]
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'subresultants'):
result = F.subresultants(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'subresultants')
return list(map(per, result))
def resultant(f, g, includePRS=False):
"""
Computes the resultant of ``f`` and ``g`` via PRS.
If includePRS=True, it includes the subresultant PRS in the result.
Because the PRS is used to calculate the resultant, this is more
efficient than calling :func:`subresultants` separately.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = Poly(x**2 + 1, x)
>>> f.resultant(Poly(x**2 - 1, x))
4
>>> f.resultant(Poly(x**2 - 1, x), includePRS=True)
(4, [Poly(x**2 + 1, x, domain='ZZ'), Poly(x**2 - 1, x, domain='ZZ'),
Poly(-2, x, domain='ZZ')])
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'resultant'):
if includePRS:
result, R = F.resultant(G, includePRS=includePRS)
else:
result = F.resultant(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'resultant')
if includePRS:
return (per(result, remove=0), list(map(per, R)))
return per(result, remove=0)
def discriminant(f):
"""
Computes the discriminant of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + 2*x + 3, x).discriminant()
-8
"""
if hasattr(f.rep, 'discriminant'):
result = f.rep.discriminant()
else: # pragma: no cover
raise OperationNotSupported(f, 'discriminant')
return f.per(result, remove=0)
def dispersionset(f, g=None):
r"""Compute the *dispersion set* of two polynomials.
For two polynomials `f(x)` and `g(x)` with `\deg f > 0`
and `\deg g > 0` the dispersion set `\operatorname{J}(f, g)` is defined as:
.. math::
\operatorname{J}(f, g)
& := \{a \in \mathbb{N}_0 | \gcd(f(x), g(x+a)) \neq 1\} \\
& = \{a \in \mathbb{N}_0 | \deg \gcd(f(x), g(x+a)) \geq 1\}
For a single polynomial one defines `\operatorname{J}(f) := \operatorname{J}(f, f)`.
Examples
========
>>> from sympy import poly
>>> from sympy.polys.dispersion import dispersion, dispersionset
>>> from sympy.abc import x
Dispersion set and dispersion of a simple polynomial:
>>> fp = poly((x - 3)*(x + 3), x)
>>> sorted(dispersionset(fp))
[0, 6]
>>> dispersion(fp)
6
Note that the definition of the dispersion is not symmetric:
>>> fp = poly(x**4 - 3*x**2 + 1, x)
>>> gp = fp.shift(-3)
>>> sorted(dispersionset(fp, gp))
[2, 3, 4]
>>> dispersion(fp, gp)
4
>>> sorted(dispersionset(gp, fp))
[]
>>> dispersion(gp, fp)
-oo
Computing the dispersion also works over field extensions:
>>> from sympy import sqrt
>>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ<sqrt(5)>')
>>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ<sqrt(5)>')
>>> sorted(dispersionset(fp, gp))
[2]
>>> sorted(dispersionset(gp, fp))
[1, 4]
We can even perform the computations for polynomials
having symbolic coefficients:
>>> from sympy.abc import a
>>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x)
>>> sorted(dispersionset(fp))
[0, 1]
See Also
========
dispersion
References
==========
1. [ManWright94]_
2. [Koepf98]_
3. [Abramov71]_
4. [Man93]_
"""
from sympy.polys.dispersion import dispersionset
return dispersionset(f, g)
def dispersion(f, g=None):
r"""Compute the *dispersion* of polynomials.
For two polynomials `f(x)` and `g(x)` with `\deg f > 0`
and `\deg g > 0` the dispersion `\operatorname{dis}(f, g)` is defined as:
.. math::
\operatorname{dis}(f, g)
& := \max\{ J(f,g) \cup \{0\} \} \\
& = \max\{ \{a \in \mathbb{N} | \gcd(f(x), g(x+a)) \neq 1\} \cup \{0\} \}
and for a single polynomial `\operatorname{dis}(f) := \operatorname{dis}(f, f)`.
Examples
========
>>> from sympy import poly
>>> from sympy.polys.dispersion import dispersion, dispersionset
>>> from sympy.abc import x
Dispersion set and dispersion of a simple polynomial:
>>> fp = poly((x - 3)*(x + 3), x)
>>> sorted(dispersionset(fp))
[0, 6]
>>> dispersion(fp)
6
Note that the definition of the dispersion is not symmetric:
>>> fp = poly(x**4 - 3*x**2 + 1, x)
>>> gp = fp.shift(-3)
>>> sorted(dispersionset(fp, gp))
[2, 3, 4]
>>> dispersion(fp, gp)
4
>>> sorted(dispersionset(gp, fp))
[]
>>> dispersion(gp, fp)
-oo
Computing the dispersion also works over field extensions:
>>> from sympy import sqrt
>>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ<sqrt(5)>')
>>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ<sqrt(5)>')
>>> sorted(dispersionset(fp, gp))
[2]
>>> sorted(dispersionset(gp, fp))
[1, 4]
We can even perform the computations for polynomials
having symbolic coefficients:
>>> from sympy.abc import a
>>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x)
>>> sorted(dispersionset(fp))
[0, 1]
See Also
========
dispersionset
References
==========
1. [ManWright94]_
2. [Koepf98]_
3. [Abramov71]_
4. [Man93]_
"""
from sympy.polys.dispersion import dispersion
return dispersion(f, g)
def cofactors(f, g):
"""
Returns the GCD of ``f`` and ``g`` and their cofactors.
Returns polynomials ``(h, cff, cfg)`` such that ``h = gcd(f, g)``, and
``cff = quo(f, h)`` and ``cfg = quo(g, h)`` are, so called, cofactors
of ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).cofactors(Poly(x**2 - 3*x + 2, x))
(Poly(x - 1, x, domain='ZZ'),
Poly(x + 1, x, domain='ZZ'),
Poly(x - 2, x, domain='ZZ'))
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'cofactors'):
h, cff, cfg = F.cofactors(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'cofactors')
return per(h), per(cff), per(cfg)
def gcd(f, g):
"""
Returns the polynomial GCD of ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).gcd(Poly(x**2 - 3*x + 2, x))
Poly(x - 1, x, domain='ZZ')
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'gcd'):
result = F.gcd(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'gcd')
return per(result)
def lcm(f, g):
"""
Returns polynomial LCM of ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 1, x).lcm(Poly(x**2 - 3*x + 2, x))
Poly(x**3 - 2*x**2 - x + 2, x, domain='ZZ')
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'lcm'):
result = F.lcm(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'lcm')
return per(result)
def trunc(f, p):
"""
Reduce ``f`` modulo a constant ``p``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**3 + 3*x**2 + 5*x + 7, x).trunc(3)
Poly(-x**3 - x + 1, x, domain='ZZ')
"""
p = f.rep.dom.convert(p)
if hasattr(f.rep, 'trunc'):
result = f.rep.trunc(p)
else: # pragma: no cover
raise OperationNotSupported(f, 'trunc')
return f.per(result)
def monic(self, auto=True):
"""
Divides all coefficients by ``LC(f)``.
Examples
========
>>> from sympy import Poly, ZZ
>>> from sympy.abc import x
>>> Poly(3*x**2 + 6*x + 9, x, domain=ZZ).monic()
Poly(x**2 + 2*x + 3, x, domain='QQ')
>>> Poly(3*x**2 + 4*x + 2, x, domain=ZZ).monic()
Poly(x**2 + 4/3*x + 2/3, x, domain='QQ')
"""
f = self
if auto and f.rep.dom.is_Ring:
f = f.to_field()
if hasattr(f.rep, 'monic'):
result = f.rep.monic()
else: # pragma: no cover
raise OperationNotSupported(f, 'monic')
return f.per(result)
def content(f):
"""
Returns the GCD of polynomial coefficients.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(6*x**2 + 8*x + 12, x).content()
2
"""
if hasattr(f.rep, 'content'):
result = f.rep.content()
else: # pragma: no cover
raise OperationNotSupported(f, 'content')
return f.rep.dom.to_sympy(result)
def primitive(f):
"""
Returns the content and a primitive form of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**2 + 8*x + 12, x).primitive()
(2, Poly(x**2 + 4*x + 6, x, domain='ZZ'))
"""
if hasattr(f.rep, 'primitive'):
cont, result = f.rep.primitive()
else: # pragma: no cover
raise OperationNotSupported(f, 'primitive')
return f.rep.dom.to_sympy(cont), f.per(result)
def compose(f, g):
"""
Computes the functional composition of ``f`` and ``g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + x, x).compose(Poly(x - 1, x))
Poly(x**2 - x, x, domain='ZZ')
"""
_, per, F, G = f._unify(g)
if hasattr(f.rep, 'compose'):
result = F.compose(G)
else: # pragma: no cover
raise OperationNotSupported(f, 'compose')
return per(result)
def decompose(f):
"""
Computes a functional decomposition of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**4 + 2*x**3 - x - 1, x, domain='ZZ').decompose()
[Poly(x**2 - x - 1, x, domain='ZZ'), Poly(x**2 + x, x, domain='ZZ')]
"""
if hasattr(f.rep, 'decompose'):
result = f.rep.decompose()
else: # pragma: no cover
raise OperationNotSupported(f, 'decompose')
return list(map(f.per, result))
def shift(f, a):
"""
Efficiently compute Taylor shift ``f(x + a)``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 2*x + 1, x).shift(2)
Poly(x**2 + 2*x + 1, x, domain='ZZ')
"""
if hasattr(f.rep, 'shift'):
result = f.rep.shift(a)
else: # pragma: no cover
raise OperationNotSupported(f, 'shift')
return f.per(result)
def transform(f, p, q):
"""
Efficiently evaluate the functional transformation ``q**n * f(p/q)``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 2*x + 1, x).transform(Poly(x + 1, x), Poly(x - 1, x))
Poly(4, x, domain='ZZ')
"""
P, Q = p.unify(q)
F, P = f.unify(P)
F, Q = F.unify(Q)
if hasattr(F.rep, 'transform'):
result = F.rep.transform(P.rep, Q.rep)
else: # pragma: no cover
raise OperationNotSupported(F, 'transform')
return F.per(result)
def sturm(self, auto=True):
"""
Computes the Sturm sequence of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 - 2*x**2 + x - 3, x).sturm()
[Poly(x**3 - 2*x**2 + x - 3, x, domain='QQ'),
Poly(3*x**2 - 4*x + 1, x, domain='QQ'),
Poly(2/9*x + 25/9, x, domain='QQ'),
Poly(-2079/4, x, domain='QQ')]
"""
f = self
if auto and f.rep.dom.is_Ring:
f = f.to_field()
if hasattr(f.rep, 'sturm'):
result = f.rep.sturm()
else: # pragma: no cover
raise OperationNotSupported(f, 'sturm')
return list(map(f.per, result))
def gff_list(f):
"""
Computes greatest factorial factorization of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = x**5 + 2*x**4 - x**3 - 2*x**2
>>> Poly(f).gff_list()
[(Poly(x, x, domain='ZZ'), 1), (Poly(x + 2, x, domain='ZZ'), 4)]
"""
if hasattr(f.rep, 'gff_list'):
result = f.rep.gff_list()
else: # pragma: no cover
raise OperationNotSupported(f, 'gff_list')
return [(f.per(g), k) for g, k in result]
def norm(f):
"""
Computes the product, ``Norm(f)``, of the conjugates of
a polynomial ``f`` defined over a number field ``K``.
Examples
========
>>> from sympy import Poly, sqrt
>>> from sympy.abc import x
>>> a, b = sqrt(2), sqrt(3)
A polynomial over a quadratic extension.
Two conjugates x - a and x + a.
>>> f = Poly(x - a, x, extension=a)
>>> f.norm()
Poly(x**2 - 2, x, domain='QQ')
A polynomial over a quartic extension.
Four conjugates x - a, x - a, x + a and x + a.
>>> f = Poly(x - a, x, extension=(a, b))
>>> f.norm()
Poly(x**4 - 4*x**2 + 4, x, domain='QQ')
"""
if hasattr(f.rep, 'norm'):
r = f.rep.norm()
else: # pragma: no cover
raise OperationNotSupported(f, 'norm')
return f.per(r)
def sqf_norm(f):
"""
Computes square-free norm of ``f``.
Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and
``r(x) = Norm(g(x))`` is a square-free polynomial over ``K``,
where ``a`` is the algebraic extension of the ground domain.
Examples
========
>>> from sympy import Poly, sqrt
>>> from sympy.abc import x
>>> s, f, r = Poly(x**2 + 1, x, extension=[sqrt(3)]).sqf_norm()
>>> s
1
>>> f
Poly(x**2 - 2*sqrt(3)*x + 4, x, domain='QQ<sqrt(3)>')
>>> r
Poly(x**4 - 4*x**2 + 16, x, domain='QQ')
"""
if hasattr(f.rep, 'sqf_norm'):
s, g, r = f.rep.sqf_norm()
else: # pragma: no cover
raise OperationNotSupported(f, 'sqf_norm')
return s, f.per(g), f.per(r)
def sqf_part(f):
"""
Computes square-free part of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**3 - 3*x - 2, x).sqf_part()
Poly(x**2 - x - 2, x, domain='ZZ')
"""
if hasattr(f.rep, 'sqf_part'):
result = f.rep.sqf_part()
else: # pragma: no cover
raise OperationNotSupported(f, 'sqf_part')
return f.per(result)
def sqf_list(f, all=False):
"""
Returns a list of square-free factors of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = 2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16
>>> Poly(f).sqf_list()
(2, [(Poly(x + 1, x, domain='ZZ'), 2),
(Poly(x + 2, x, domain='ZZ'), 3)])
>>> Poly(f).sqf_list(all=True)
(2, [(Poly(1, x, domain='ZZ'), 1),
(Poly(x + 1, x, domain='ZZ'), 2),
(Poly(x + 2, x, domain='ZZ'), 3)])
"""
if hasattr(f.rep, 'sqf_list'):
coeff, factors = f.rep.sqf_list(all)
else: # pragma: no cover
raise OperationNotSupported(f, 'sqf_list')
return f.rep.dom.to_sympy(coeff), [(f.per(g), k) for g, k in factors]
def sqf_list_include(f, all=False):
"""
Returns a list of square-free factors of ``f``.
Examples
========
>>> from sympy import Poly, expand
>>> from sympy.abc import x
>>> f = expand(2*(x + 1)**3*x**4)
>>> f
2*x**7 + 6*x**6 + 6*x**5 + 2*x**4
>>> Poly(f).sqf_list_include()
[(Poly(2, x, domain='ZZ'), 1),
(Poly(x + 1, x, domain='ZZ'), 3),
(Poly(x, x, domain='ZZ'), 4)]
>>> Poly(f).sqf_list_include(all=True)
[(Poly(2, x, domain='ZZ'), 1),
(Poly(1, x, domain='ZZ'), 2),
(Poly(x + 1, x, domain='ZZ'), 3),
(Poly(x, x, domain='ZZ'), 4)]
"""
if hasattr(f.rep, 'sqf_list_include'):
factors = f.rep.sqf_list_include(all)
else: # pragma: no cover
raise OperationNotSupported(f, 'sqf_list_include')
return [(f.per(g), k) for g, k in factors]
def factor_list(f):
"""
Returns a list of irreducible factors of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = 2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y
>>> Poly(f).factor_list()
(2, [(Poly(x + y, x, y, domain='ZZ'), 1),
(Poly(x**2 + 1, x, y, domain='ZZ'), 2)])
"""
if hasattr(f.rep, 'factor_list'):
try:
coeff, factors = f.rep.factor_list()
except DomainError:
return S.One, [(f, 1)]
else: # pragma: no cover
raise OperationNotSupported(f, 'factor_list')
return f.rep.dom.to_sympy(coeff), [(f.per(g), k) for g, k in factors]
def factor_list_include(f):
"""
Returns a list of irreducible factors of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> f = 2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y
>>> Poly(f).factor_list_include()
[(Poly(2*x + 2*y, x, y, domain='ZZ'), 1),
(Poly(x**2 + 1, x, y, domain='ZZ'), 2)]
"""
if hasattr(f.rep, 'factor_list_include'):
try:
factors = f.rep.factor_list_include()
except DomainError:
return [(f, 1)]
else: # pragma: no cover
raise OperationNotSupported(f, 'factor_list_include')
return [(f.per(g), k) for g, k in factors]
def intervals(f, all=False, eps=None, inf=None, sup=None, fast=False, sqf=False):
"""
Compute isolating intervals for roots of ``f``.
For real roots the Vincent-Akritas-Strzebonski (VAS) continued fractions method is used.
References
==========
.. [#] Alkiviadis G. Akritas and Adam W. Strzebonski: A Comparative Study of Two Real Root
Isolation Methods . Nonlinear Analysis: Modelling and Control, Vol. 10, No. 4, 297-304, 2005.
.. [#] Alkiviadis G. Akritas, Adam W. Strzebonski and Panagiotis S. Vigklas: Improving the
Performance of the Continued Fractions Method Using new Bounds of Positive Roots. Nonlinear
Analysis: Modelling and Control, Vol. 13, No. 3, 265-279, 2008.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 3, x).intervals()
[((-2, -1), 1), ((1, 2), 1)]
>>> Poly(x**2 - 3, x).intervals(eps=1e-2)
[((-26/15, -19/11), 1), ((19/11, 26/15), 1)]
"""
if eps is not None:
eps = QQ.convert(eps)
if eps <= 0:
raise ValueError("'eps' must be a positive rational")
if inf is not None:
inf = QQ.convert(inf)
if sup is not None:
sup = QQ.convert(sup)
if hasattr(f.rep, 'intervals'):
result = f.rep.intervals(
all=all, eps=eps, inf=inf, sup=sup, fast=fast, sqf=sqf)
else: # pragma: no cover
raise OperationNotSupported(f, 'intervals')
if sqf:
def _real(interval):
s, t = interval
return (QQ.to_sympy(s), QQ.to_sympy(t))
if not all:
return list(map(_real, result))
def _complex(rectangle):
(u, v), (s, t) = rectangle
return (QQ.to_sympy(u) + I*QQ.to_sympy(v),
QQ.to_sympy(s) + I*QQ.to_sympy(t))
real_part, complex_part = result
return list(map(_real, real_part)), list(map(_complex, complex_part))
else:
def _real(interval):
(s, t), k = interval
return ((QQ.to_sympy(s), QQ.to_sympy(t)), k)
if not all:
return list(map(_real, result))
def _complex(rectangle):
((u, v), (s, t)), k = rectangle
return ((QQ.to_sympy(u) + I*QQ.to_sympy(v),
QQ.to_sympy(s) + I*QQ.to_sympy(t)), k)
real_part, complex_part = result
return list(map(_real, real_part)), list(map(_complex, complex_part))
def refine_root(f, s, t, eps=None, steps=None, fast=False, check_sqf=False):
"""
Refine an isolating interval of a root to the given precision.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 3, x).refine_root(1, 2, eps=1e-2)
(19/11, 26/15)
"""
if check_sqf and not f.is_sqf:
raise PolynomialError("only square-free polynomials supported")
s, t = QQ.convert(s), QQ.convert(t)
if eps is not None:
eps = QQ.convert(eps)
if eps <= 0:
raise ValueError("'eps' must be a positive rational")
if steps is not None:
steps = int(steps)
elif eps is None:
steps = 1
if hasattr(f.rep, 'refine_root'):
S, T = f.rep.refine_root(s, t, eps=eps, steps=steps, fast=fast)
else: # pragma: no cover
raise OperationNotSupported(f, 'refine_root')
return QQ.to_sympy(S), QQ.to_sympy(T)
def count_roots(f, inf=None, sup=None):
"""
Return the number of roots of ``f`` in ``[inf, sup]`` interval.
Examples
========
>>> from sympy import Poly, I
>>> from sympy.abc import x
>>> Poly(x**4 - 4, x).count_roots(-3, 3)
2
>>> Poly(x**4 - 4, x).count_roots(0, 1 + 3*I)
1
"""
inf_real, sup_real = True, True
if inf is not None:
inf = sympify(inf)
if inf is S.NegativeInfinity:
inf = None
else:
re, im = inf.as_real_imag()
if not im:
inf = QQ.convert(inf)
else:
inf, inf_real = list(map(QQ.convert, (re, im))), False
if sup is not None:
sup = sympify(sup)
if sup is S.Infinity:
sup = None
else:
re, im = sup.as_real_imag()
if not im:
sup = QQ.convert(sup)
else:
sup, sup_real = list(map(QQ.convert, (re, im))), False
if inf_real and sup_real:
if hasattr(f.rep, 'count_real_roots'):
count = f.rep.count_real_roots(inf=inf, sup=sup)
else: # pragma: no cover
raise OperationNotSupported(f, 'count_real_roots')
else:
if inf_real and inf is not None:
inf = (inf, QQ.zero)
if sup_real and sup is not None:
sup = (sup, QQ.zero)
if hasattr(f.rep, 'count_complex_roots'):
count = f.rep.count_complex_roots(inf=inf, sup=sup)
else: # pragma: no cover
raise OperationNotSupported(f, 'count_complex_roots')
return Integer(count)
def root(f, index, radicals=True):
"""
Get an indexed root of a polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = Poly(2*x**3 - 7*x**2 + 4*x + 4)
>>> f.root(0)
-1/2
>>> f.root(1)
2
>>> f.root(2)
2
>>> f.root(3)
Traceback (most recent call last):
...
IndexError: root index out of [-3, 2] range, got 3
>>> Poly(x**5 + x + 1).root(0)
CRootOf(x**3 - x**2 + 1, 0)
"""
return sympy.polys.rootoftools.rootof(f, index, radicals=radicals)
def real_roots(f, multiple=True, radicals=True):
"""
Return a list of real roots with multiplicities.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**3 - 7*x**2 + 4*x + 4).real_roots()
[-1/2, 2, 2]
>>> Poly(x**3 + x + 1).real_roots()
[CRootOf(x**3 + x + 1, 0)]
"""
reals = sympy.polys.rootoftools.CRootOf.real_roots(f, radicals=radicals)
if multiple:
return reals
else:
return group(reals, multiple=False)
def all_roots(f, multiple=True, radicals=True):
"""
Return a list of real and complex roots with multiplicities.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**3 - 7*x**2 + 4*x + 4).all_roots()
[-1/2, 2, 2]
>>> Poly(x**3 + x + 1).all_roots()
[CRootOf(x**3 + x + 1, 0),
CRootOf(x**3 + x + 1, 1),
CRootOf(x**3 + x + 1, 2)]
"""
roots = sympy.polys.rootoftools.CRootOf.all_roots(f, radicals=radicals)
if multiple:
return roots
else:
return group(roots, multiple=False)
def nroots(f, n=15, maxsteps=50, cleanup=True):
"""
Compute numerical approximations of roots of ``f``.
Parameters
==========
n ... the number of digits to calculate
maxsteps ... the maximum number of iterations to do
If the accuracy `n` cannot be reached in `maxsteps`, it will raise an
exception. You need to rerun with higher maxsteps.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 3).nroots(n=15)
[-1.73205080756888, 1.73205080756888]
>>> Poly(x**2 - 3).nroots(n=30)
[-1.73205080756887729352744634151, 1.73205080756887729352744634151]
"""
from sympy.functions.elementary.complexes import sign
if f.is_multivariate:
raise MultivariatePolynomialError(
"can't compute numerical roots of %s" % f)
if f.degree() <= 0:
return []
# For integer and rational coefficients, convert them to integers only
# (for accuracy). Otherwise just try to convert the coefficients to
# mpmath.mpc and raise an exception if the conversion fails.
if f.rep.dom is ZZ:
coeffs = [int(coeff) for coeff in f.all_coeffs()]
elif f.rep.dom is QQ:
denoms = [coeff.q for coeff in f.all_coeffs()]
from sympy.core.numbers import ilcm
fac = ilcm(*denoms)
coeffs = [int(coeff*fac) for coeff in f.all_coeffs()]
else:
coeffs = [coeff.evalf(n=n).as_real_imag()
for coeff in f.all_coeffs()]
try:
coeffs = [mpmath.mpc(*coeff) for coeff in coeffs]
except TypeError:
raise DomainError("Numerical domain expected, got %s" % \
f.rep.dom)
dps = mpmath.mp.dps
mpmath.mp.dps = n
try:
# We need to add extra precision to guard against losing accuracy.
# 10 times the degree of the polynomial seems to work well.
roots = mpmath.polyroots(coeffs, maxsteps=maxsteps,
cleanup=cleanup, error=False, extraprec=f.degree()*10)
# Mpmath puts real roots first, then complex ones (as does all_roots)
# so we make sure this convention holds here, too.
roots = list(map(sympify,
sorted(roots, key=lambda r: (1 if r.imag else 0, r.real, abs(r.imag), sign(r.imag)))))
except NoConvergence:
raise NoConvergence(
'convergence to root failed; try n < %s or maxsteps > %s' % (
n, maxsteps))
finally:
mpmath.mp.dps = dps
return roots
def ground_roots(f):
"""
Compute roots of ``f`` by factorization in the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**6 - 4*x**4 + 4*x**3 - x**2).ground_roots()
{0: 2, 1: 2}
"""
if f.is_multivariate:
raise MultivariatePolynomialError(
"can't compute ground roots of %s" % f)
roots = {}
for factor, k in f.factor_list()[1]:
if factor.is_linear:
a, b = factor.all_coeffs()
roots[-b/a] = k
return roots
def nth_power_roots_poly(f, n):
"""
Construct a polynomial with n-th powers of roots of ``f``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = Poly(x**4 - x**2 + 1)
>>> f.nth_power_roots_poly(2)
Poly(x**4 - 2*x**3 + 3*x**2 - 2*x + 1, x, domain='ZZ')
>>> f.nth_power_roots_poly(3)
Poly(x**4 + 2*x**2 + 1, x, domain='ZZ')
>>> f.nth_power_roots_poly(4)
Poly(x**4 + 2*x**3 + 3*x**2 + 2*x + 1, x, domain='ZZ')
>>> f.nth_power_roots_poly(12)
Poly(x**4 - 4*x**3 + 6*x**2 - 4*x + 1, x, domain='ZZ')
"""
if f.is_multivariate:
raise MultivariatePolynomialError(
"must be a univariate polynomial")
N = sympify(n)
if N.is_Integer and N >= 1:
n = int(N)
else:
raise ValueError("'n' must an integer and n >= 1, got %s" % n)
x = f.gen
t = Dummy('t')
r = f.resultant(f.__class__.from_expr(x**n - t, x, t))
return r.replace(t, x)
def cancel(f, g, include=False):
"""
Cancel common factors in a rational function ``f/g``.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**2 - 2, x).cancel(Poly(x**2 - 2*x + 1, x))
(1, Poly(2*x + 2, x, domain='ZZ'), Poly(x - 1, x, domain='ZZ'))
>>> Poly(2*x**2 - 2, x).cancel(Poly(x**2 - 2*x + 1, x), include=True)
(Poly(2*x + 2, x, domain='ZZ'), Poly(x - 1, x, domain='ZZ'))
"""
dom, per, F, G = f._unify(g)
if hasattr(F, 'cancel'):
result = F.cancel(G, include=include)
else: # pragma: no cover
raise OperationNotSupported(f, 'cancel')
if not include:
if dom.has_assoc_Ring:
dom = dom.get_ring()
cp, cq, p, q = result
cp = dom.to_sympy(cp)
cq = dom.to_sympy(cq)
return cp/cq, per(p), per(q)
else:
return tuple(map(per, result))
@property
def is_zero(f):
"""
Returns ``True`` if ``f`` is a zero polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(0, x).is_zero
True
>>> Poly(1, x).is_zero
False
"""
return f.rep.is_zero
@property
def is_one(f):
"""
Returns ``True`` if ``f`` is a unit polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(0, x).is_one
False
>>> Poly(1, x).is_one
True
"""
return f.rep.is_one
@property
def is_sqf(f):
"""
Returns ``True`` if ``f`` is a square-free polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 - 2*x + 1, x).is_sqf
False
>>> Poly(x**2 - 1, x).is_sqf
True
"""
return f.rep.is_sqf
@property
def is_monic(f):
"""
Returns ``True`` if the leading coefficient of ``f`` is one.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x + 2, x).is_monic
True
>>> Poly(2*x + 2, x).is_monic
False
"""
return f.rep.is_monic
@property
def is_primitive(f):
"""
Returns ``True`` if GCD of the coefficients of ``f`` is one.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(2*x**2 + 6*x + 12, x).is_primitive
False
>>> Poly(x**2 + 3*x + 6, x).is_primitive
True
"""
return f.rep.is_primitive
@property
def is_ground(f):
"""
Returns ``True`` if ``f`` is an element of the ground domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x, x).is_ground
False
>>> Poly(2, x).is_ground
True
>>> Poly(y, x).is_ground
True
"""
return f.rep.is_ground
@property
def is_linear(f):
"""
Returns ``True`` if ``f`` is linear in all its variables.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x + y + 2, x, y).is_linear
True
>>> Poly(x*y + 2, x, y).is_linear
False
"""
return f.rep.is_linear
@property
def is_quadratic(f):
"""
Returns ``True`` if ``f`` is quadratic in all its variables.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x*y + 2, x, y).is_quadratic
True
>>> Poly(x*y**2 + 2, x, y).is_quadratic
False
"""
return f.rep.is_quadratic
@property
def is_monomial(f):
"""
Returns ``True`` if ``f`` is zero or has only one term.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(3*x**2, x).is_monomial
True
>>> Poly(3*x**2 + 1, x).is_monomial
False
"""
return f.rep.is_monomial
@property
def is_homogeneous(f):
"""
Returns ``True`` if ``f`` is a homogeneous polynomial.
A homogeneous polynomial is a polynomial whose all monomials with
non-zero coefficients have the same total degree. If you want not
only to check if a polynomial is homogeneous but also compute its
homogeneous order, then use :func:`Poly.homogeneous_order`.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + x*y, x, y).is_homogeneous
True
>>> Poly(x**3 + x*y, x, y).is_homogeneous
False
"""
return f.rep.is_homogeneous
@property
def is_irreducible(f):
"""
Returns ``True`` if ``f`` has no factors over its domain.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> Poly(x**2 + x + 1, x, modulus=2).is_irreducible
True
>>> Poly(x**2 + 1, x, modulus=2).is_irreducible
False
"""
return f.rep.is_irreducible
@property
def is_univariate(f):
"""
Returns ``True`` if ``f`` is a univariate polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + x + 1, x).is_univariate
True
>>> Poly(x*y**2 + x*y + 1, x, y).is_univariate
False
>>> Poly(x*y**2 + x*y + 1, x).is_univariate
True
>>> Poly(x**2 + x + 1, x, y).is_univariate
False
"""
return len(f.gens) == 1
@property
def is_multivariate(f):
"""
Returns ``True`` if ``f`` is a multivariate polynomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x, y
>>> Poly(x**2 + x + 1, x).is_multivariate
False
>>> Poly(x*y**2 + x*y + 1, x, y).is_multivariate
True
>>> Poly(x*y**2 + x*y + 1, x).is_multivariate
False
>>> Poly(x**2 + x + 1, x, y).is_multivariate
True
"""
return len(f.gens) != 1
@property
def is_cyclotomic(f):
"""
Returns ``True`` if ``f`` is a cyclotomic polnomial.
Examples
========
>>> from sympy import Poly
>>> from sympy.abc import x
>>> f = x**16 + x**14 - x**10 + x**8 - x**6 + x**2 + 1
>>> Poly(f).is_cyclotomic
False
>>> g = x**16 + x**14 - x**10 - x**8 - x**6 + x**2 + 1
>>> Poly(g).is_cyclotomic
True
"""
return f.rep.is_cyclotomic
def __abs__(f):
return f.abs()
def __neg__(f):
return f.neg()
@_sympifyit('g', NotImplemented)
def __add__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return f.as_expr() + g
return f.add(g)
@_sympifyit('g', NotImplemented)
def __radd__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return g + f.as_expr()
return g.add(f)
@_sympifyit('g', NotImplemented)
def __sub__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return f.as_expr() - g
return f.sub(g)
@_sympifyit('g', NotImplemented)
def __rsub__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return g - f.as_expr()
return g.sub(f)
@_sympifyit('g', NotImplemented)
def __mul__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return f.as_expr()*g
return f.mul(g)
@_sympifyit('g', NotImplemented)
def __rmul__(f, g):
if not g.is_Poly:
try:
g = f.__class__(g, *f.gens)
except PolynomialError:
return g*f.as_expr()
return g.mul(f)
@_sympifyit('n', NotImplemented)
def __pow__(f, n):
if n.is_Integer and n >= 0:
return f.pow(n)
else:
return f.as_expr()**n
@_sympifyit('g', NotImplemented)
def __divmod__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return f.div(g)
@_sympifyit('g', NotImplemented)
def __rdivmod__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return g.div(f)
@_sympifyit('g', NotImplemented)
def __mod__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return f.rem(g)
@_sympifyit('g', NotImplemented)
def __rmod__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return g.rem(f)
@_sympifyit('g', NotImplemented)
def __floordiv__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return f.quo(g)
@_sympifyit('g', NotImplemented)
def __rfloordiv__(f, g):
if not g.is_Poly:
g = f.__class__(g, *f.gens)
return g.quo(f)
@_sympifyit('g', NotImplemented)
def __div__(f, g):
return f.as_expr()/g.as_expr()
@_sympifyit('g', NotImplemented)
def __rdiv__(f, g):
return g.as_expr()/f.as_expr()
__truediv__ = __div__
__rtruediv__ = __rdiv__
@_sympifyit('other', NotImplemented)
def __eq__(self, other):
f, g = self, other
if not g.is_Poly:
try:
g = f.__class__(g, f.gens, domain=f.get_domain())
except (PolynomialError, DomainError, CoercionFailed):
return False
if f.gens != g.gens:
return False
if f.rep.dom != g.rep.dom:
try:
dom = f.rep.dom.unify(g.rep.dom, f.gens)
except UnificationFailed:
return False
f = f.set_domain(dom)
g = g.set_domain(dom)
return f.rep == g.rep
@_sympifyit('g', NotImplemented)
def __ne__(f, g):
return not f == g
def __nonzero__(f):
return not f.is_zero
__bool__ = __nonzero__
def eq(f, g, strict=False):
if not strict:
return f == g
else:
return f._strict_eq(sympify(g))
def ne(f, g, strict=False):
return not f.eq(g, strict=strict)
def _strict_eq(f, g):
return isinstance(g, f.__class__) and f.gens == g.gens and f.rep.eq(g.rep, strict=True)
@public
class PurePoly(Poly):
"""Class for representing pure polynomials. """
def _hashable_content(self):
"""Allow SymPy to hash Poly instances. """
return (self.rep,)
def __hash__(self):
return super(PurePoly, self).__hash__()
@property
def free_symbols(self):
"""
Free symbols of a polynomial.
Examples
========
>>> from sympy import PurePoly
>>> from sympy.abc import x, y
>>> PurePoly(x**2 + 1).free_symbols
set()
>>> PurePoly(x**2 + y).free_symbols
set()
>>> PurePoly(x**2 + y, x).free_symbols
{y}
"""
return self.free_symbols_in_domain
@_sympifyit('other', NotImplemented)
def __eq__(self, other):
f, g = self, other
if not g.is_Poly:
try:
g = f.__class__(g, f.gens, domain=f.get_domain())
except (PolynomialError, DomainError, CoercionFailed):
return False
if len(f.gens) != len(g.gens):
return False
if f.rep.dom != g.rep.dom:
try:
dom = f.rep.dom.unify(g.rep.dom, f.gens)
except UnificationFailed:
return False
f = f.set_domain(dom)
g = g.set_domain(dom)
return f.rep == g.rep
def _strict_eq(f, g):
return isinstance(g, f.__class__) and f.rep.eq(g.rep, strict=True)
def _unify(f, g):
g = sympify(g)
if not g.is_Poly:
try:
return f.rep.dom, f.per, f.rep, f.rep.per(f.rep.dom.from_sympy(g))
except CoercionFailed:
raise UnificationFailed("can't unify %s with %s" % (f, g))
if len(f.gens) != len(g.gens):
raise UnificationFailed("can't unify %s with %s" % (f, g))
if not (isinstance(f.rep, DMP) and isinstance(g.rep, DMP)):
raise UnificationFailed("can't unify %s with %s" % (f, g))
cls = f.__class__
gens = f.gens
dom = f.rep.dom.unify(g.rep.dom, gens)
F = f.rep.convert(dom)
G = g.rep.convert(dom)
def per(rep, dom=dom, gens=gens, remove=None):
if remove is not None:
gens = gens[:remove] + gens[remove + 1:]
if not gens:
return dom.to_sympy(rep)
return cls.new(rep, *gens)
return dom, per, F, G
@public
def poly_from_expr(expr, *gens, **args):
"""Construct a polynomial from an expression. """
opt = options.build_options(gens, args)
return _poly_from_expr(expr, opt)
def _poly_from_expr(expr, opt):
"""Construct a polynomial from an expression. """
orig, expr = expr, sympify(expr)
if not isinstance(expr, Basic):
raise PolificationFailed(opt, orig, expr)
elif expr.is_Poly:
poly = expr.__class__._from_poly(expr, opt)
opt.gens = poly.gens
opt.domain = poly.domain
if opt.polys is None:
opt.polys = True
return poly, opt
elif opt.expand:
expr = expr.expand()
rep, opt = _dict_from_expr(expr, opt)
if not opt.gens:
raise PolificationFailed(opt, orig, expr)
monoms, coeffs = list(zip(*list(rep.items())))
domain = opt.domain
if domain is None:
opt.domain, coeffs = construct_domain(coeffs, opt=opt)
else:
coeffs = list(map(domain.from_sympy, coeffs))
rep = dict(list(zip(monoms, coeffs)))
poly = Poly._from_dict(rep, opt)
if opt.polys is None:
opt.polys = False
return poly, opt
@public
def parallel_poly_from_expr(exprs, *gens, **args):
"""Construct polynomials from expressions. """
opt = options.build_options(gens, args)
return _parallel_poly_from_expr(exprs, opt)
def _parallel_poly_from_expr(exprs, opt):
"""Construct polynomials from expressions. """
from sympy.functions.elementary.piecewise import Piecewise
if len(exprs) == 2:
f, g = exprs
if isinstance(f, Poly) and isinstance(g, Poly):
f = f.__class__._from_poly(f, opt)
g = g.__class__._from_poly(g, opt)
f, g = f.unify(g)
opt.gens = f.gens
opt.domain = f.domain
if opt.polys is None:
opt.polys = True
return [f, g], opt
origs, exprs = list(exprs), []
_exprs, _polys = [], []
failed = False
for i, expr in enumerate(origs):
expr = sympify(expr)
if isinstance(expr, Basic):
if expr.is_Poly:
_polys.append(i)
else:
_exprs.append(i)
if opt.expand:
expr = expr.expand()
else:
failed = True
exprs.append(expr)
if failed:
raise PolificationFailed(opt, origs, exprs, True)
if _polys:
# XXX: this is a temporary solution
for i in _polys:
exprs[i] = exprs[i].as_expr()
reps, opt = _parallel_dict_from_expr(exprs, opt)
if not opt.gens:
raise PolificationFailed(opt, origs, exprs, True)
for k in opt.gens:
if isinstance(k, Piecewise):
raise PolynomialError("Piecewise generators do not make sense")
coeffs_list, lengths = [], []
all_monoms = []
all_coeffs = []
for rep in reps:
monoms, coeffs = list(zip(*list(rep.items())))
coeffs_list.extend(coeffs)
all_monoms.append(monoms)
lengths.append(len(coeffs))
domain = opt.domain
if domain is None:
opt.domain, coeffs_list = construct_domain(coeffs_list, opt=opt)
else:
coeffs_list = list(map(domain.from_sympy, coeffs_list))
for k in lengths:
all_coeffs.append(coeffs_list[:k])
coeffs_list = coeffs_list[k:]
polys = []
for monoms, coeffs in zip(all_monoms, all_coeffs):
rep = dict(list(zip(monoms, coeffs)))
poly = Poly._from_dict(rep, opt)
polys.append(poly)
if opt.polys is None:
opt.polys = bool(_polys)
return polys, opt
def _update_args(args, key, value):
"""Add a new ``(key, value)`` pair to arguments ``dict``. """
args = dict(args)
if key not in args:
args[key] = value
return args
@public
def degree(f, gen=0):
"""
Return the degree of ``f`` in the given variable.
The degree of 0 is negative infinity.
Examples
========
>>> from sympy import degree
>>> from sympy.abc import x, y
>>> degree(x**2 + y*x + 1, gen=x)
2
>>> degree(x**2 + y*x + 1, gen=y)
1
>>> degree(0, x)
-oo
See also
========
total_degree
degree_list
"""
f = sympify(f, strict=True)
gen_is_Num = sympify(gen, strict=True).is_Number
if f.is_Poly:
p = f
isNum = p.as_expr().is_Number
else:
isNum = f.is_Number
if not isNum:
if gen_is_Num:
p, _ = poly_from_expr(f)
else:
p, _ = poly_from_expr(f, gen)
if isNum:
return S.Zero if f else S.NegativeInfinity
if not gen_is_Num:
if f.is_Poly and gen not in p.gens:
# try recast without explicit gens
p, _ = poly_from_expr(f.as_expr())
if gen not in p.gens:
return S.Zero
elif not f.is_Poly and len(f.free_symbols) > 1:
raise TypeError(filldedent('''
A symbolic generator of interest is required for a multivariate
expression like func = %s, e.g. degree(func, gen = %s) instead of
degree(func, gen = %s).
''' % (f, next(ordered(f.free_symbols)), gen)))
return Integer(p.degree(gen))
@public
def total_degree(f, *gens):
"""
Return the total_degree of ``f`` in the given variables.
Examples
========
>>> from sympy import total_degree, Poly
>>> from sympy.abc import x, y, z
>>> total_degree(1)
0
>>> total_degree(x + x*y)
2
>>> total_degree(x + x*y, x)
1
If the expression is a Poly and no variables are given
then the generators of the Poly will be used:
>>> p = Poly(x + x*y, y)
>>> total_degree(p)
1
To deal with the underlying expression of the Poly, convert
it to an Expr:
>>> total_degree(p.as_expr())
2
This is done automatically if any variables are given:
>>> total_degree(p, x)
1
See also
========
degree
"""
p = sympify(f)
if p.is_Poly:
p = p.as_expr()
if p.is_Number:
rv = 0
else:
if f.is_Poly:
gens = gens or f.gens
rv = Poly(p, gens).total_degree()
return Integer(rv)
@public
def degree_list(f, *gens, **args):
"""
Return a list of degrees of ``f`` in all variables.
Examples
========
>>> from sympy import degree_list
>>> from sympy.abc import x, y
>>> degree_list(x**2 + y*x + 1)
(2, 1)
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('degree_list', 1, exc)
degrees = F.degree_list()
return tuple(map(Integer, degrees))
@public
def LC(f, *gens, **args):
"""
Return the leading coefficient of ``f``.
Examples
========
>>> from sympy import LC
>>> from sympy.abc import x, y
>>> LC(4*x**2 + 2*x*y**2 + x*y + 3*y)
4
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('LC', 1, exc)
return F.LC(order=opt.order)
@public
def LM(f, *gens, **args):
"""
Return the leading monomial of ``f``.
Examples
========
>>> from sympy import LM
>>> from sympy.abc import x, y
>>> LM(4*x**2 + 2*x*y**2 + x*y + 3*y)
x**2
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('LM', 1, exc)
monom = F.LM(order=opt.order)
return monom.as_expr()
@public
def LT(f, *gens, **args):
"""
Return the leading term of ``f``.
Examples
========
>>> from sympy import LT
>>> from sympy.abc import x, y
>>> LT(4*x**2 + 2*x*y**2 + x*y + 3*y)
4*x**2
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('LT', 1, exc)
monom, coeff = F.LT(order=opt.order)
return coeff*monom.as_expr()
@public
def pdiv(f, g, *gens, **args):
"""
Compute polynomial pseudo-division of ``f`` and ``g``.
Examples
========
>>> from sympy import pdiv
>>> from sympy.abc import x
>>> pdiv(x**2 + 1, 2*x - 4)
(2*x + 4, 20)
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('pdiv', 2, exc)
q, r = F.pdiv(G)
if not opt.polys:
return q.as_expr(), r.as_expr()
else:
return q, r
@public
def prem(f, g, *gens, **args):
"""
Compute polynomial pseudo-remainder of ``f`` and ``g``.
Examples
========
>>> from sympy import prem
>>> from sympy.abc import x
>>> prem(x**2 + 1, 2*x - 4)
20
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('prem', 2, exc)
r = F.prem(G)
if not opt.polys:
return r.as_expr()
else:
return r
@public
def pquo(f, g, *gens, **args):
"""
Compute polynomial pseudo-quotient of ``f`` and ``g``.
Examples
========
>>> from sympy import pquo
>>> from sympy.abc import x
>>> pquo(x**2 + 1, 2*x - 4)
2*x + 4
>>> pquo(x**2 - 1, 2*x - 1)
2*x + 1
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('pquo', 2, exc)
try:
q = F.pquo(G)
except ExactQuotientFailed:
raise ExactQuotientFailed(f, g)
if not opt.polys:
return q.as_expr()
else:
return q
@public
def pexquo(f, g, *gens, **args):
"""
Compute polynomial exact pseudo-quotient of ``f`` and ``g``.
Examples
========
>>> from sympy import pexquo
>>> from sympy.abc import x
>>> pexquo(x**2 - 1, 2*x - 2)
2*x + 2
>>> pexquo(x**2 + 1, 2*x - 4)
Traceback (most recent call last):
...
ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('pexquo', 2, exc)
q = F.pexquo(G)
if not opt.polys:
return q.as_expr()
else:
return q
@public
def div(f, g, *gens, **args):
"""
Compute polynomial division of ``f`` and ``g``.
Examples
========
>>> from sympy import div, ZZ, QQ
>>> from sympy.abc import x
>>> div(x**2 + 1, 2*x - 4, domain=ZZ)
(0, x**2 + 1)
>>> div(x**2 + 1, 2*x - 4, domain=QQ)
(x/2 + 1, 5)
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('div', 2, exc)
q, r = F.div(G, auto=opt.auto)
if not opt.polys:
return q.as_expr(), r.as_expr()
else:
return q, r
@public
def rem(f, g, *gens, **args):
"""
Compute polynomial remainder of ``f`` and ``g``.
Examples
========
>>> from sympy import rem, ZZ, QQ
>>> from sympy.abc import x
>>> rem(x**2 + 1, 2*x - 4, domain=ZZ)
x**2 + 1
>>> rem(x**2 + 1, 2*x - 4, domain=QQ)
5
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('rem', 2, exc)
r = F.rem(G, auto=opt.auto)
if not opt.polys:
return r.as_expr()
else:
return r
@public
def quo(f, g, *gens, **args):
"""
Compute polynomial quotient of ``f`` and ``g``.
Examples
========
>>> from sympy import quo
>>> from sympy.abc import x
>>> quo(x**2 + 1, 2*x - 4)
x/2 + 1
>>> quo(x**2 - 1, x - 1)
x + 1
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('quo', 2, exc)
q = F.quo(G, auto=opt.auto)
if not opt.polys:
return q.as_expr()
else:
return q
@public
def exquo(f, g, *gens, **args):
"""
Compute polynomial exact quotient of ``f`` and ``g``.
Examples
========
>>> from sympy import exquo
>>> from sympy.abc import x
>>> exquo(x**2 - 1, x - 1)
x + 1
>>> exquo(x**2 + 1, 2*x - 4)
Traceback (most recent call last):
...
ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('exquo', 2, exc)
q = F.exquo(G, auto=opt.auto)
if not opt.polys:
return q.as_expr()
else:
return q
@public
def half_gcdex(f, g, *gens, **args):
"""
Half extended Euclidean algorithm of ``f`` and ``g``.
Returns ``(s, h)`` such that ``h = gcd(f, g)`` and ``s*f = h (mod g)``.
Examples
========
>>> from sympy import half_gcdex
>>> from sympy.abc import x
>>> half_gcdex(x**4 - 2*x**3 - 6*x**2 + 12*x + 15, x**3 + x**2 - 4*x - 4)
(-x/5 + 3/5, x + 1)
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
s, h = domain.half_gcdex(a, b)
except NotImplementedError:
raise ComputationFailed('half_gcdex', 2, exc)
else:
return domain.to_sympy(s), domain.to_sympy(h)
s, h = F.half_gcdex(G, auto=opt.auto)
if not opt.polys:
return s.as_expr(), h.as_expr()
else:
return s, h
@public
def gcdex(f, g, *gens, **args):
"""
Extended Euclidean algorithm of ``f`` and ``g``.
Returns ``(s, t, h)`` such that ``h = gcd(f, g)`` and ``s*f + t*g = h``.
Examples
========
>>> from sympy import gcdex
>>> from sympy.abc import x
>>> gcdex(x**4 - 2*x**3 - 6*x**2 + 12*x + 15, x**3 + x**2 - 4*x - 4)
(-x/5 + 3/5, x**2/5 - 6*x/5 + 2, x + 1)
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
s, t, h = domain.gcdex(a, b)
except NotImplementedError:
raise ComputationFailed('gcdex', 2, exc)
else:
return domain.to_sympy(s), domain.to_sympy(t), domain.to_sympy(h)
s, t, h = F.gcdex(G, auto=opt.auto)
if not opt.polys:
return s.as_expr(), t.as_expr(), h.as_expr()
else:
return s, t, h
@public
def invert(f, g, *gens, **args):
"""
Invert ``f`` modulo ``g`` when possible.
Examples
========
>>> from sympy import invert, S
>>> from sympy.core.numbers import mod_inverse
>>> from sympy.abc import x
>>> invert(x**2 - 1, 2*x - 1)
-4/3
>>> invert(x**2 - 1, x - 1)
Traceback (most recent call last):
...
NotInvertible: zero divisor
For more efficient inversion of Rationals,
use the ``mod_inverse`` function:
>>> mod_inverse(3, 5)
2
>>> (S(2)/5).invert(S(7)/3)
5/2
See Also
========
sympy.core.numbers.mod_inverse
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
return domain.to_sympy(domain.invert(a, b))
except NotImplementedError:
raise ComputationFailed('invert', 2, exc)
h = F.invert(G, auto=opt.auto)
if not opt.polys:
return h.as_expr()
else:
return h
@public
def subresultants(f, g, *gens, **args):
"""
Compute subresultant PRS of ``f`` and ``g``.
Examples
========
>>> from sympy import subresultants
>>> from sympy.abc import x
>>> subresultants(x**2 + 1, x**2 - 1)
[x**2 + 1, x**2 - 1, -2]
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('subresultants', 2, exc)
result = F.subresultants(G)
if not opt.polys:
return [r.as_expr() for r in result]
else:
return result
@public
def resultant(f, g, *gens, **args):
"""
Compute resultant of ``f`` and ``g``.
Examples
========
>>> from sympy import resultant
>>> from sympy.abc import x
>>> resultant(x**2 + 1, x**2 - 1)
4
"""
includePRS = args.pop('includePRS', False)
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('resultant', 2, exc)
if includePRS:
result, R = F.resultant(G, includePRS=includePRS)
else:
result = F.resultant(G)
if not opt.polys:
if includePRS:
return result.as_expr(), [r.as_expr() for r in R]
return result.as_expr()
else:
if includePRS:
return result, R
return result
@public
def discriminant(f, *gens, **args):
"""
Compute discriminant of ``f``.
Examples
========
>>> from sympy import discriminant
>>> from sympy.abc import x
>>> discriminant(x**2 + 2*x + 3)
-8
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('discriminant', 1, exc)
result = F.discriminant()
if not opt.polys:
return result.as_expr()
else:
return result
@public
def cofactors(f, g, *gens, **args):
"""
Compute GCD and cofactors of ``f`` and ``g``.
Returns polynomials ``(h, cff, cfg)`` such that ``h = gcd(f, g)``, and
``cff = quo(f, h)`` and ``cfg = quo(g, h)`` are, so called, cofactors
of ``f`` and ``g``.
Examples
========
>>> from sympy import cofactors
>>> from sympy.abc import x
>>> cofactors(x**2 - 1, x**2 - 3*x + 2)
(x - 1, x + 1, x - 2)
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
h, cff, cfg = domain.cofactors(a, b)
except NotImplementedError:
raise ComputationFailed('cofactors', 2, exc)
else:
return domain.to_sympy(h), domain.to_sympy(cff), domain.to_sympy(cfg)
h, cff, cfg = F.cofactors(G)
if not opt.polys:
return h.as_expr(), cff.as_expr(), cfg.as_expr()
else:
return h, cff, cfg
@public
def gcd_list(seq, *gens, **args):
"""
Compute GCD of a list of polynomials.
Examples
========
>>> from sympy import gcd_list
>>> from sympy.abc import x
>>> gcd_list([x**3 - 1, x**2 - 1, x**2 - 3*x + 2])
x - 1
"""
seq = sympify(seq)
def try_non_polynomial_gcd(seq):
if not gens and not args:
domain, numbers = construct_domain(seq)
if not numbers:
return domain.zero
elif domain.is_Numerical:
result, numbers = numbers[0], numbers[1:]
for number in numbers:
result = domain.gcd(result, number)
if domain.is_one(result):
break
return domain.to_sympy(result)
return None
result = try_non_polynomial_gcd(seq)
if result is not None:
return result
options.allowed_flags(args, ['polys'])
try:
polys, opt = parallel_poly_from_expr(seq, *gens, **args)
# gcd for domain Q[irrational] (purely algebraic irrational)
if len(seq) > 1 and all(elt.is_algebraic and elt.is_irrational for elt in seq):
a = seq[-1]
lst = [ (a/elt).ratsimp() for elt in seq[:-1] ]
if all(frc.is_rational for frc in lst):
lc = 1
for frc in lst:
lc = lcm(lc, frc.as_numer_denom()[0])
return a/lc
except PolificationFailed as exc:
result = try_non_polynomial_gcd(exc.exprs)
if result is not None:
return result
else:
raise ComputationFailed('gcd_list', len(seq), exc)
if not polys:
if not opt.polys:
return S.Zero
else:
return Poly(0, opt=opt)
result, polys = polys[0], polys[1:]
for poly in polys:
result = result.gcd(poly)
if result.is_one:
break
if not opt.polys:
return result.as_expr()
else:
return result
@public
def gcd(f, g=None, *gens, **args):
"""
Compute GCD of ``f`` and ``g``.
Examples
========
>>> from sympy import gcd
>>> from sympy.abc import x
>>> gcd(x**2 - 1, x**2 - 3*x + 2)
x - 1
"""
if hasattr(f, '__iter__'):
if g is not None:
gens = (g,) + gens
return gcd_list(f, *gens, **args)
elif g is None:
raise TypeError("gcd() takes 2 arguments or a sequence of arguments")
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
# gcd for domain Q[irrational] (purely algebraic irrational)
a, b = map(sympify, (f, g))
if a.is_algebraic and a.is_irrational and b.is_algebraic and b.is_irrational:
frc = (a/b).ratsimp()
if frc.is_rational:
return a/frc.as_numer_denom()[0]
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
return domain.to_sympy(domain.gcd(a, b))
except NotImplementedError:
raise ComputationFailed('gcd', 2, exc)
result = F.gcd(G)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def lcm_list(seq, *gens, **args):
"""
Compute LCM of a list of polynomials.
Examples
========
>>> from sympy import lcm_list
>>> from sympy.abc import x
>>> lcm_list([x**3 - 1, x**2 - 1, x**2 - 3*x + 2])
x**5 - x**4 - 2*x**3 - x**2 + x + 2
"""
seq = sympify(seq)
def try_non_polynomial_lcm(seq):
if not gens and not args:
domain, numbers = construct_domain(seq)
if not numbers:
return domain.one
elif domain.is_Numerical:
result, numbers = numbers[0], numbers[1:]
for number in numbers:
result = domain.lcm(result, number)
return domain.to_sympy(result)
return None
result = try_non_polynomial_lcm(seq)
if result is not None:
return result
options.allowed_flags(args, ['polys'])
try:
polys, opt = parallel_poly_from_expr(seq, *gens, **args)
# lcm for domain Q[irrational] (purely algebraic irrational)
if len(seq) > 1 and all(elt.is_algebraic and elt.is_irrational for elt in seq):
a = seq[-1]
lst = [ (a/elt).ratsimp() for elt in seq[:-1] ]
if all(frc.is_rational for frc in lst):
lc = 1
for frc in lst:
lc = lcm(lc, frc.as_numer_denom()[1])
return a*lc
except PolificationFailed as exc:
result = try_non_polynomial_lcm(exc.exprs)
if result is not None:
return result
else:
raise ComputationFailed('lcm_list', len(seq), exc)
if not polys:
if not opt.polys:
return S.One
else:
return Poly(1, opt=opt)
result, polys = polys[0], polys[1:]
for poly in polys:
result = result.lcm(poly)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def lcm(f, g=None, *gens, **args):
"""
Compute LCM of ``f`` and ``g``.
Examples
========
>>> from sympy import lcm
>>> from sympy.abc import x
>>> lcm(x**2 - 1, x**2 - 3*x + 2)
x**3 - 2*x**2 - x + 2
"""
if hasattr(f, '__iter__'):
if g is not None:
gens = (g,) + gens
return lcm_list(f, *gens, **args)
elif g is None:
raise TypeError("lcm() takes 2 arguments or a sequence of arguments")
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
# lcm for domain Q[irrational] (purely algebraic irrational)
a, b = map(sympify, (f, g))
if a.is_algebraic and a.is_irrational and b.is_algebraic and b.is_irrational:
frc = (a/b).ratsimp()
if frc.is_rational:
return a*frc.as_numer_denom()[1]
except PolificationFailed as exc:
domain, (a, b) = construct_domain(exc.exprs)
try:
return domain.to_sympy(domain.lcm(a, b))
except NotImplementedError:
raise ComputationFailed('lcm', 2, exc)
result = F.lcm(G)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def terms_gcd(f, *gens, **args):
"""
Remove GCD of terms from ``f``.
If the ``deep`` flag is True, then the arguments of ``f`` will have
terms_gcd applied to them.
If a fraction is factored out of ``f`` and ``f`` is an Add, then
an unevaluated Mul will be returned so that automatic simplification
does not redistribute it. The hint ``clear``, when set to False, can be
used to prevent such factoring when all coefficients are not fractions.
Examples
========
>>> from sympy import terms_gcd, cos
>>> from sympy.abc import x, y
>>> terms_gcd(x**6*y**2 + x**3*y, x, y)
x**3*y*(x**3*y + 1)
The default action of polys routines is to expand the expression
given to them. terms_gcd follows this behavior:
>>> terms_gcd((3+3*x)*(x+x*y))
3*x*(x*y + x + y + 1)
If this is not desired then the hint ``expand`` can be set to False.
In this case the expression will be treated as though it were comprised
of one or more terms:
>>> terms_gcd((3+3*x)*(x+x*y), expand=False)
(3*x + 3)*(x*y + x)
In order to traverse factors of a Mul or the arguments of other
functions, the ``deep`` hint can be used:
>>> terms_gcd((3 + 3*x)*(x + x*y), expand=False, deep=True)
3*x*(x + 1)*(y + 1)
>>> terms_gcd(cos(x + x*y), deep=True)
cos(x*(y + 1))
Rationals are factored out by default:
>>> terms_gcd(x + y/2)
(2*x + y)/2
Only the y-term had a coefficient that was a fraction; if one
does not want to factor out the 1/2 in cases like this, the
flag ``clear`` can be set to False:
>>> terms_gcd(x + y/2, clear=False)
x + y/2
>>> terms_gcd(x*y/2 + y**2, clear=False)
y*(x/2 + y)
The ``clear`` flag is ignored if all coefficients are fractions:
>>> terms_gcd(x/3 + y/2, clear=False)
(2*x + 3*y)/6
See Also
========
sympy.core.exprtools.gcd_terms, sympy.core.exprtools.factor_terms
"""
from sympy.core.relational import Equality
orig = sympify(f)
if not isinstance(f, Expr) or f.is_Atom:
return orig
if args.get('deep', False):
new = f.func(*[terms_gcd(a, *gens, **args) for a in f.args])
args.pop('deep')
args['expand'] = False
return terms_gcd(new, *gens, **args)
if isinstance(f, Equality):
return f
clear = args.pop('clear', True)
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
return exc.expr
J, f = F.terms_gcd()
if opt.domain.is_Ring:
if opt.domain.is_Field:
denom, f = f.clear_denoms(convert=True)
coeff, f = f.primitive()
if opt.domain.is_Field:
coeff /= denom
else:
coeff = S.One
term = Mul(*[x**j for x, j in zip(f.gens, J)])
if coeff == 1:
coeff = S.One
if term == 1:
return orig
if clear:
return _keep_coeff(coeff, term*f.as_expr())
# base the clearing on the form of the original expression, not
# the (perhaps) Mul that we have now
coeff, f = _keep_coeff(coeff, f.as_expr(), clear=False).as_coeff_Mul()
return _keep_coeff(coeff, term*f, clear=False)
@public
def trunc(f, p, *gens, **args):
"""
Reduce ``f`` modulo a constant ``p``.
Examples
========
>>> from sympy import trunc
>>> from sympy.abc import x
>>> trunc(2*x**3 + 3*x**2 + 5*x + 7, 3)
-x**3 - x + 1
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('trunc', 1, exc)
result = F.trunc(sympify(p))
if not opt.polys:
return result.as_expr()
else:
return result
@public
def monic(f, *gens, **args):
"""
Divide all coefficients of ``f`` by ``LC(f)``.
Examples
========
>>> from sympy import monic
>>> from sympy.abc import x
>>> monic(3*x**2 + 4*x + 2)
x**2 + 4*x/3 + 2/3
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('monic', 1, exc)
result = F.monic(auto=opt.auto)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def content(f, *gens, **args):
"""
Compute GCD of coefficients of ``f``.
Examples
========
>>> from sympy import content
>>> from sympy.abc import x
>>> content(6*x**2 + 8*x + 12)
2
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('content', 1, exc)
return F.content()
@public
def primitive(f, *gens, **args):
"""
Compute content and the primitive form of ``f``.
Examples
========
>>> from sympy.polys.polytools import primitive
>>> from sympy.abc import x
>>> primitive(6*x**2 + 8*x + 12)
(2, 3*x**2 + 4*x + 6)
>>> eq = (2 + 2*x)*x + 2
Expansion is performed by default:
>>> primitive(eq)
(2, x**2 + x + 1)
Set ``expand`` to False to shut this off. Note that the
extraction will not be recursive; use the as_content_primitive method
for recursive, non-destructive Rational extraction.
>>> primitive(eq, expand=False)
(1, x*(2*x + 2) + 2)
>>> eq.as_content_primitive()
(2, x*(x + 1) + 1)
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('primitive', 1, exc)
cont, result = F.primitive()
if not opt.polys:
return cont, result.as_expr()
else:
return cont, result
@public
def compose(f, g, *gens, **args):
"""
Compute functional composition ``f(g)``.
Examples
========
>>> from sympy import compose
>>> from sympy.abc import x
>>> compose(x**2 + x, x - 1)
x**2 - x
"""
options.allowed_flags(args, ['polys'])
try:
(F, G), opt = parallel_poly_from_expr((f, g), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('compose', 2, exc)
result = F.compose(G)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def decompose(f, *gens, **args):
"""
Compute functional decomposition of ``f``.
Examples
========
>>> from sympy import decompose
>>> from sympy.abc import x
>>> decompose(x**4 + 2*x**3 - x - 1)
[x**2 - x - 1, x**2 + x]
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('decompose', 1, exc)
result = F.decompose()
if not opt.polys:
return [r.as_expr() for r in result]
else:
return result
@public
def sturm(f, *gens, **args):
"""
Compute Sturm sequence of ``f``.
Examples
========
>>> from sympy import sturm
>>> from sympy.abc import x
>>> sturm(x**3 - 2*x**2 + x - 3)
[x**3 - 2*x**2 + x - 3, 3*x**2 - 4*x + 1, 2*x/9 + 25/9, -2079/4]
"""
options.allowed_flags(args, ['auto', 'polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('sturm', 1, exc)
result = F.sturm(auto=opt.auto)
if not opt.polys:
return [r.as_expr() for r in result]
else:
return result
@public
def gff_list(f, *gens, **args):
"""
Compute a list of greatest factorial factors of ``f``.
Note that the input to ff() and rf() should be Poly instances to use the
definitions here.
Examples
========
>>> from sympy import gff_list, ff, Poly
>>> from sympy.abc import x
>>> f = Poly(x**5 + 2*x**4 - x**3 - 2*x**2, x)
>>> gff_list(f)
[(Poly(x, x, domain='ZZ'), 1), (Poly(x + 2, x, domain='ZZ'), 4)]
>>> (ff(Poly(x), 1)*ff(Poly(x + 2), 4)).expand() == f
True
>>> f = Poly(x**12 + 6*x**11 - 11*x**10 - 56*x**9 + 220*x**8 + 208*x**7 - \
1401*x**6 + 1090*x**5 + 2715*x**4 - 6720*x**3 - 1092*x**2 + 5040*x, x)
>>> gff_list(f)
[(Poly(x**3 + 7, x, domain='ZZ'), 2), (Poly(x**2 + 5*x, x, domain='ZZ'), 3)]
>>> ff(Poly(x**3 + 7, x), 2)*ff(Poly(x**2 + 5*x, x), 3) == f
True
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('gff_list', 1, exc)
factors = F.gff_list()
if not opt.polys:
return [(g.as_expr(), k) for g, k in factors]
else:
return factors
@public
def gff(f, *gens, **args):
"""Compute greatest factorial factorization of ``f``. """
raise NotImplementedError('symbolic falling factorial')
@public
def sqf_norm(f, *gens, **args):
"""
Compute square-free norm of ``f``.
Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and
``r(x) = Norm(g(x))`` is a square-free polynomial over ``K``,
where ``a`` is the algebraic extension of the ground domain.
Examples
========
>>> from sympy import sqf_norm, sqrt
>>> from sympy.abc import x
>>> sqf_norm(x**2 + 1, extension=[sqrt(3)])
(1, x**2 - 2*sqrt(3)*x + 4, x**4 - 4*x**2 + 16)
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('sqf_norm', 1, exc)
s, g, r = F.sqf_norm()
if not opt.polys:
return Integer(s), g.as_expr(), r.as_expr()
else:
return Integer(s), g, r
@public
def sqf_part(f, *gens, **args):
"""
Compute square-free part of ``f``.
Examples
========
>>> from sympy import sqf_part
>>> from sympy.abc import x
>>> sqf_part(x**3 - 3*x - 2)
x**2 - x - 2
"""
options.allowed_flags(args, ['polys'])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('sqf_part', 1, exc)
result = F.sqf_part()
if not opt.polys:
return result.as_expr()
else:
return result
def _sorted_factors(factors, method):
"""Sort a list of ``(expr, exp)`` pairs. """
if method == 'sqf':
def key(obj):
poly, exp = obj
rep = poly.rep.rep
return (exp, len(rep), len(poly.gens), rep)
else:
def key(obj):
poly, exp = obj
rep = poly.rep.rep
return (len(rep), len(poly.gens), exp, rep)
return sorted(factors, key=key)
def _factors_product(factors):
"""Multiply a list of ``(expr, exp)`` pairs. """
return Mul(*[f.as_expr()**k for f, k in factors])
def _symbolic_factor_list(expr, opt, method):
"""Helper function for :func:`_symbolic_factor`. """
coeff, factors = S.One, []
args = [i._eval_factor() if hasattr(i, '_eval_factor') else i
for i in Mul.make_args(expr)]
for arg in args:
if arg.is_Number:
coeff *= arg
continue
if arg.is_Mul:
args.extend(arg.args)
continue
if arg.is_Pow:
base, exp = arg.args
if base.is_Number and exp.is_Number:
coeff *= arg
continue
if base.is_Number:
factors.append((base, exp))
continue
else:
base, exp = arg, S.One
try:
poly, _ = _poly_from_expr(base, opt)
except PolificationFailed as exc:
factors.append((exc.expr, exp))
else:
func = getattr(poly, method + '_list')
_coeff, _factors = func()
if _coeff is not S.One:
if exp.is_Integer:
coeff *= _coeff**exp
elif _coeff.is_positive:
factors.append((_coeff, exp))
else:
_factors.append((_coeff, S.One))
if exp is S.One:
factors.extend(_factors)
elif exp.is_integer:
factors.extend([(f, k*exp) for f, k in _factors])
else:
other = []
for f, k in _factors:
if f.as_expr().is_positive:
factors.append((f, k*exp))
else:
other.append((f, k))
factors.append((_factors_product(other), exp))
return coeff, factors
def _symbolic_factor(expr, opt, method):
"""Helper function for :func:`_factor`. """
if isinstance(expr, Expr) and not expr.is_Relational:
if hasattr(expr,'_eval_factor'):
return expr._eval_factor()
coeff, factors = _symbolic_factor_list(together(expr), opt, method)
return _keep_coeff(coeff, _factors_product(factors))
elif hasattr(expr, 'args'):
return expr.func(*[_symbolic_factor(arg, opt, method) for arg in expr.args])
elif hasattr(expr, '__iter__'):
return expr.__class__([_symbolic_factor(arg, opt, method) for arg in expr])
else:
return expr
def _generic_factor_list(expr, gens, args, method):
"""Helper function for :func:`sqf_list` and :func:`factor_list`. """
options.allowed_flags(args, ['frac', 'polys'])
opt = options.build_options(gens, args)
expr = sympify(expr)
if isinstance(expr, Expr) and not expr.is_Relational:
numer, denom = together(expr).as_numer_denom()
cp, fp = _symbolic_factor_list(numer, opt, method)
cq, fq = _symbolic_factor_list(denom, opt, method)
if fq and not opt.frac:
raise PolynomialError("a polynomial expected, got %s" % expr)
_opt = opt.clone(dict(expand=True))
for factors in (fp, fq):
for i, (f, k) in enumerate(factors):
if not f.is_Poly:
f, _ = _poly_from_expr(f, _opt)
factors[i] = (f, k)
fp = _sorted_factors(fp, method)
fq = _sorted_factors(fq, method)
if not opt.polys:
fp = [(f.as_expr(), k) for f, k in fp]
fq = [(f.as_expr(), k) for f, k in fq]
coeff = cp/cq
if not opt.frac:
return coeff, fp
else:
return coeff, fp, fq
else:
raise PolynomialError("a polynomial expected, got %s" % expr)
def _generic_factor(expr, gens, args, method):
"""Helper function for :func:`sqf` and :func:`factor`. """
options.allowed_flags(args, [])
opt = options.build_options(gens, args)
return _symbolic_factor(sympify(expr), opt, method)
def to_rational_coeffs(f):
"""
try to transform a polynomial to have rational coefficients
try to find a transformation ``x = alpha*y``
``f(x) = lc*alpha**n * g(y)`` where ``g`` is a polynomial with
rational coefficients, ``lc`` the leading coefficient.
If this fails, try ``x = y + beta``
``f(x) = g(y)``
Returns ``None`` if ``g`` not found;
``(lc, alpha, None, g)`` in case of rescaling
``(None, None, beta, g)`` in case of translation
Notes
=====
Currently it transforms only polynomials without roots larger than 2.
Examples
========
>>> from sympy import sqrt, Poly, simplify
>>> from sympy.polys.polytools import to_rational_coeffs
>>> from sympy.abc import x
>>> p = Poly(((x**2-1)*(x-2)).subs({x:x*(1 + sqrt(2))}), x, domain='EX')
>>> lc, r, _, g = to_rational_coeffs(p)
>>> lc, r
(7 + 5*sqrt(2), -2*sqrt(2) + 2)
>>> g
Poly(x**3 + x**2 - 1/4*x - 1/4, x, domain='QQ')
>>> r1 = simplify(1/r)
>>> Poly(lc*r**3*(g.as_expr()).subs({x:x*r1}), x, domain='EX') == p
True
"""
from sympy.simplify.simplify import simplify
def _try_rescale(f, f1=None):
"""
try rescaling ``x -> alpha*x`` to convert f to a polynomial
with rational coefficients.
Returns ``alpha, f``; if the rescaling is successful,
``alpha`` is the rescaling factor, and ``f`` is the rescaled
polynomial; else ``alpha`` is ``None``.
"""
from sympy.core.add import Add
if not len(f.gens) == 1 or not (f.gens[0]).is_Atom:
return None, f
n = f.degree()
lc = f.LC()
f1 = f1 or f1.monic()
coeffs = f1.all_coeffs()[1:]
coeffs = [simplify(coeffx) for coeffx in coeffs]
if coeffs[-2]:
rescale1_x = simplify(coeffs[-2]/coeffs[-1])
coeffs1 = []
for i in range(len(coeffs)):
coeffx = simplify(coeffs[i]*rescale1_x**(i + 1))
if not coeffx.is_rational:
break
coeffs1.append(coeffx)
else:
rescale_x = simplify(1/rescale1_x)
x = f.gens[0]
v = [x**n]
for i in range(1, n + 1):
v.append(coeffs1[i - 1]*x**(n - i))
f = Add(*v)
f = Poly(f)
return lc, rescale_x, f
return None
def _try_translate(f, f1=None):
"""
try translating ``x -> x + alpha`` to convert f to a polynomial
with rational coefficients.
Returns ``alpha, f``; if the translating is successful,
``alpha`` is the translating factor, and ``f`` is the shifted
polynomial; else ``alpha`` is ``None``.
"""
from sympy.core.add import Add
if not len(f.gens) == 1 or not (f.gens[0]).is_Atom:
return None, f
n = f.degree()
f1 = f1 or f1.monic()
coeffs = f1.all_coeffs()[1:]
c = simplify(coeffs[0])
if c and not c.is_rational:
func = Add
if c.is_Add:
args = c.args
func = c.func
else:
args = [c]
c1, c2 = sift(args, lambda z: z.is_rational, binary=True)
alpha = -func(*c2)/n
f2 = f1.shift(alpha)
return alpha, f2
return None
def _has_square_roots(p):
"""
Return True if ``f`` is a sum with square roots but no other root
"""
from sympy.core.exprtools import Factors
coeffs = p.coeffs()
has_sq = False
for y in coeffs:
for x in Add.make_args(y):
f = Factors(x).factors
r = [wx.q for b, wx in f.items() if
b.is_number and wx.is_Rational and wx.q >= 2]
if not r:
continue
if min(r) == 2:
has_sq = True
if max(r) > 2:
return False
return has_sq
if f.get_domain().is_EX and _has_square_roots(f):
f1 = f.monic()
r = _try_rescale(f, f1)
if r:
return r[0], r[1], None, r[2]
else:
r = _try_translate(f, f1)
if r:
return None, None, r[0], r[1]
return None
def _torational_factor_list(p, x):
"""
helper function to factor polynomial using to_rational_coeffs
Examples
========
>>> from sympy.polys.polytools import _torational_factor_list
>>> from sympy.abc import x
>>> from sympy import sqrt, expand, Mul
>>> p = expand(((x**2-1)*(x-2)).subs({x:x*(1 + sqrt(2))}))
>>> factors = _torational_factor_list(p, x); factors
(-2, [(-x*(1 + sqrt(2))/2 + 1, 1), (-x*(1 + sqrt(2)) - 1, 1), (-x*(1 + sqrt(2)) + 1, 1)])
>>> expand(factors[0]*Mul(*[z[0] for z in factors[1]])) == p
True
>>> p = expand(((x**2-1)*(x-2)).subs({x:x + sqrt(2)}))
>>> factors = _torational_factor_list(p, x); factors
(1, [(x - 2 + sqrt(2), 1), (x - 1 + sqrt(2), 1), (x + 1 + sqrt(2), 1)])
>>> expand(factors[0]*Mul(*[z[0] for z in factors[1]])) == p
True
"""
from sympy.simplify.simplify import simplify
p1 = Poly(p, x, domain='EX')
n = p1.degree()
res = to_rational_coeffs(p1)
if not res:
return None
lc, r, t, g = res
factors = factor_list(g.as_expr())
if lc:
c = simplify(factors[0]*lc*r**n)
r1 = simplify(1/r)
a = []
for z in factors[1:][0]:
a.append((simplify(z[0].subs({x: x*r1})), z[1]))
else:
c = factors[0]
a = []
for z in factors[1:][0]:
a.append((z[0].subs({x: x - t}), z[1]))
return (c, a)
@public
def sqf_list(f, *gens, **args):
"""
Compute a list of square-free factors of ``f``.
Examples
========
>>> from sympy import sqf_list
>>> from sympy.abc import x
>>> sqf_list(2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16)
(2, [(x + 1, 2), (x + 2, 3)])
"""
return _generic_factor_list(f, gens, args, method='sqf')
@public
def sqf(f, *gens, **args):
"""
Compute square-free factorization of ``f``.
Examples
========
>>> from sympy import sqf
>>> from sympy.abc import x
>>> sqf(2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16)
2*(x + 1)**2*(x + 2)**3
"""
return _generic_factor(f, gens, args, method='sqf')
@public
def factor_list(f, *gens, **args):
"""
Compute a list of irreducible factors of ``f``.
Examples
========
>>> from sympy import factor_list
>>> from sympy.abc import x, y
>>> factor_list(2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y)
(2, [(x + y, 1), (x**2 + 1, 2)])
"""
return _generic_factor_list(f, gens, args, method='factor')
@public
def factor(f, *gens, **args):
"""
Compute the factorization of expression, ``f``, into irreducibles. (To
factor an integer into primes, use ``factorint``.)
There two modes implemented: symbolic and formal. If ``f`` is not an
instance of :class:`Poly` and generators are not specified, then the
former mode is used. Otherwise, the formal mode is used.
In symbolic mode, :func:`factor` will traverse the expression tree and
factor its components without any prior expansion, unless an instance
of :class:`Add` is encountered (in this case formal factorization is
used). This way :func:`factor` can handle large or symbolic exponents.
By default, the factorization is computed over the rationals. To factor
over other domain, e.g. an algebraic or finite field, use appropriate
options: ``extension``, ``modulus`` or ``domain``.
Examples
========
>>> from sympy import factor, sqrt
>>> from sympy.abc import x, y
>>> factor(2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y)
2*(x + y)*(x**2 + 1)**2
>>> factor(x**2 + 1)
x**2 + 1
>>> factor(x**2 + 1, modulus=2)
(x + 1)**2
>>> factor(x**2 + 1, gaussian=True)
(x - I)*(x + I)
>>> factor(x**2 - 2, extension=sqrt(2))
(x - sqrt(2))*(x + sqrt(2))
>>> factor((x**2 - 1)/(x**2 + 4*x + 4))
(x - 1)*(x + 1)/(x + 2)**2
>>> factor((x**2 + 4*x + 4)**10000000*(x**2 + 1))
(x + 2)**20000000*(x**2 + 1)
By default, factor deals with an expression as a whole:
>>> eq = 2**(x**2 + 2*x + 1)
>>> factor(eq)
2**(x**2 + 2*x + 1)
If the ``deep`` flag is True then subexpressions will
be factored:
>>> factor(eq, deep=True)
2**((x + 1)**2)
See Also
========
sympy.ntheory.factor_.factorint
"""
f = sympify(f)
if args.pop('deep', False):
from sympy.simplify.simplify import bottom_up
def _try_factor(expr):
"""
Factor, but avoid changing the expression when unable to.
"""
fac = factor(expr)
if fac.is_Mul or fac.is_Pow:
return fac
return expr
f = bottom_up(f, _try_factor)
# clean up any subexpressions that may have been expanded
# while factoring out a larger expression
partials = {}
muladd = f.atoms(Mul, Add)
for p in muladd:
fac = factor(p, *gens, **args)
if (fac.is_Mul or fac.is_Pow) and fac != p:
partials[p] = fac
return f.xreplace(partials)
try:
return _generic_factor(f, gens, args, method='factor')
except PolynomialError as msg:
if not f.is_commutative:
from sympy.core.exprtools import factor_nc
return factor_nc(f)
else:
raise PolynomialError(msg)
@public
def intervals(F, all=False, eps=None, inf=None, sup=None, strict=False, fast=False, sqf=False):
"""
Compute isolating intervals for roots of ``f``.
Examples
========
>>> from sympy import intervals
>>> from sympy.abc import x
>>> intervals(x**2 - 3)
[((-2, -1), 1), ((1, 2), 1)]
>>> intervals(x**2 - 3, eps=1e-2)
[((-26/15, -19/11), 1), ((19/11, 26/15), 1)]
"""
if not hasattr(F, '__iter__'):
try:
F = Poly(F)
except GeneratorsNeeded:
return []
return F.intervals(all=all, eps=eps, inf=inf, sup=sup, fast=fast, sqf=sqf)
else:
polys, opt = parallel_poly_from_expr(F, domain='QQ')
if len(opt.gens) > 1:
raise MultivariatePolynomialError
for i, poly in enumerate(polys):
polys[i] = poly.rep.rep
if eps is not None:
eps = opt.domain.convert(eps)
if eps <= 0:
raise ValueError("'eps' must be a positive rational")
if inf is not None:
inf = opt.domain.convert(inf)
if sup is not None:
sup = opt.domain.convert(sup)
intervals = dup_isolate_real_roots_list(polys, opt.domain,
eps=eps, inf=inf, sup=sup, strict=strict, fast=fast)
result = []
for (s, t), indices in intervals:
s, t = opt.domain.to_sympy(s), opt.domain.to_sympy(t)
result.append(((s, t), indices))
return result
@public
def refine_root(f, s, t, eps=None, steps=None, fast=False, check_sqf=False):
"""
Refine an isolating interval of a root to the given precision.
Examples
========
>>> from sympy import refine_root
>>> from sympy.abc import x
>>> refine_root(x**2 - 3, 1, 2, eps=1e-2)
(19/11, 26/15)
"""
try:
F = Poly(f)
except GeneratorsNeeded:
raise PolynomialError(
"can't refine a root of %s, not a polynomial" % f)
return F.refine_root(s, t, eps=eps, steps=steps, fast=fast, check_sqf=check_sqf)
@public
def count_roots(f, inf=None, sup=None):
"""
Return the number of roots of ``f`` in ``[inf, sup]`` interval.
If one of ``inf`` or ``sup`` is complex, it will return the number of roots
in the complex rectangle with corners at ``inf`` and ``sup``.
Examples
========
>>> from sympy import count_roots, I
>>> from sympy.abc import x
>>> count_roots(x**4 - 4, -3, 3)
2
>>> count_roots(x**4 - 4, 0, 1 + 3*I)
1
"""
try:
F = Poly(f, greedy=False)
except GeneratorsNeeded:
raise PolynomialError("can't count roots of %s, not a polynomial" % f)
return F.count_roots(inf=inf, sup=sup)
@public
def real_roots(f, multiple=True):
"""
Return a list of real roots with multiplicities of ``f``.
Examples
========
>>> from sympy import real_roots
>>> from sympy.abc import x
>>> real_roots(2*x**3 - 7*x**2 + 4*x + 4)
[-1/2, 2, 2]
"""
try:
F = Poly(f, greedy=False)
except GeneratorsNeeded:
raise PolynomialError(
"can't compute real roots of %s, not a polynomial" % f)
return F.real_roots(multiple=multiple)
@public
def nroots(f, n=15, maxsteps=50, cleanup=True):
"""
Compute numerical approximations of roots of ``f``.
Examples
========
>>> from sympy import nroots
>>> from sympy.abc import x
>>> nroots(x**2 - 3, n=15)
[-1.73205080756888, 1.73205080756888]
>>> nroots(x**2 - 3, n=30)
[-1.73205080756887729352744634151, 1.73205080756887729352744634151]
"""
try:
F = Poly(f, greedy=False)
except GeneratorsNeeded:
raise PolynomialError(
"can't compute numerical roots of %s, not a polynomial" % f)
return F.nroots(n=n, maxsteps=maxsteps, cleanup=cleanup)
@public
def ground_roots(f, *gens, **args):
"""
Compute roots of ``f`` by factorization in the ground domain.
Examples
========
>>> from sympy import ground_roots
>>> from sympy.abc import x
>>> ground_roots(x**6 - 4*x**4 + 4*x**3 - x**2)
{0: 2, 1: 2}
"""
options.allowed_flags(args, [])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('ground_roots', 1, exc)
return F.ground_roots()
@public
def nth_power_roots_poly(f, n, *gens, **args):
"""
Construct a polynomial with n-th powers of roots of ``f``.
Examples
========
>>> from sympy import nth_power_roots_poly, factor, roots
>>> from sympy.abc import x
>>> f = x**4 - x**2 + 1
>>> g = factor(nth_power_roots_poly(f, 2))
>>> g
(x**2 - x + 1)**2
>>> R_f = [ (r**2).expand() for r in roots(f) ]
>>> R_g = roots(g).keys()
>>> set(R_f) == set(R_g)
True
"""
options.allowed_flags(args, [])
try:
F, opt = poly_from_expr(f, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('nth_power_roots_poly', 1, exc)
result = F.nth_power_roots_poly(n)
if not opt.polys:
return result.as_expr()
else:
return result
@public
def cancel(f, *gens, **args):
"""
Cancel common factors in a rational function ``f``.
Examples
========
>>> from sympy import cancel, sqrt, Symbol
>>> from sympy.abc import x
>>> A = Symbol('A', commutative=False)
>>> cancel((2*x**2 - 2)/(x**2 - 2*x + 1))
(2*x + 2)/(x - 1)
>>> cancel((sqrt(3) + sqrt(15)*A)/(sqrt(2) + sqrt(10)*A))
sqrt(6)/2
"""
from sympy.core.exprtools import factor_terms
from sympy.functions.elementary.piecewise import Piecewise
options.allowed_flags(args, ['polys'])
f = sympify(f)
if not isinstance(f, (tuple, Tuple)):
if f.is_Number or isinstance(f, Relational) or not isinstance(f, Expr):
return f
f = factor_terms(f, radical=True)
p, q = f.as_numer_denom()
elif len(f) == 2:
p, q = f
elif isinstance(f, Tuple):
return factor_terms(f)
else:
raise ValueError('unexpected argument: %s' % f)
try:
(F, G), opt = parallel_poly_from_expr((p, q), *gens, **args)
except PolificationFailed:
if not isinstance(f, (tuple, Tuple)):
return f
else:
return S.One, p, q
except PolynomialError as msg:
if f.is_commutative and not f.has(Piecewise):
raise PolynomialError(msg)
# Handling of noncommutative and/or piecewise expressions
if f.is_Add or f.is_Mul:
c, nc = sift(f.args, lambda x:
x.is_commutative is True and not x.has(Piecewise),
binary=True)
nc = [cancel(i) for i in nc]
return f.func(cancel(f.func._from_args(c)), *nc)
else:
reps = []
pot = preorder_traversal(f)
next(pot)
for e in pot:
# XXX: This should really skip anything that's not Expr.
if isinstance(e, (tuple, Tuple, BooleanAtom)):
continue
try:
reps.append((e, cancel(e)))
pot.skip() # this was handled successfully
except NotImplementedError:
pass
return f.xreplace(dict(reps))
c, P, Q = F.cancel(G)
if not isinstance(f, (tuple, Tuple)):
return c*(P.as_expr()/Q.as_expr())
else:
if not opt.polys:
return c, P.as_expr(), Q.as_expr()
else:
return c, P, Q
@public
def reduced(f, G, *gens, **args):
"""
Reduces a polynomial ``f`` modulo a set of polynomials ``G``.
Given a polynomial ``f`` and a set of polynomials ``G = (g_1, ..., g_n)``,
computes a set of quotients ``q = (q_1, ..., q_n)`` and the remainder ``r``
such that ``f = q_1*g_1 + ... + q_n*g_n + r``, where ``r`` vanishes or ``r``
is a completely reduced polynomial with respect to ``G``.
Examples
========
>>> from sympy import reduced
>>> from sympy.abc import x, y
>>> reduced(2*x**4 + y**2 - x**2 + y**3, [x**3 - x, y**3 - y])
([2*x, 1], x**2 + y**2 + y)
"""
options.allowed_flags(args, ['polys', 'auto'])
try:
polys, opt = parallel_poly_from_expr([f] + list(G), *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('reduced', 0, exc)
domain = opt.domain
retract = False
if opt.auto and domain.is_Ring and not domain.is_Field:
opt = opt.clone(dict(domain=domain.get_field()))
retract = True
from sympy.polys.rings import xring
_ring, _ = xring(opt.gens, opt.domain, opt.order)
for i, poly in enumerate(polys):
poly = poly.set_domain(opt.domain).rep.to_dict()
polys[i] = _ring.from_dict(poly)
Q, r = polys[0].div(polys[1:])
Q = [Poly._from_dict(dict(q), opt) for q in Q]
r = Poly._from_dict(dict(r), opt)
if retract:
try:
_Q, _r = [q.to_ring() for q in Q], r.to_ring()
except CoercionFailed:
pass
else:
Q, r = _Q, _r
if not opt.polys:
return [q.as_expr() for q in Q], r.as_expr()
else:
return Q, r
@public
def groebner(F, *gens, **args):
"""
Computes the reduced Groebner basis for a set of polynomials.
Use the ``order`` argument to set the monomial ordering that will be
used to compute the basis. Allowed orders are ``lex``, ``grlex`` and
``grevlex``. If no order is specified, it defaults to ``lex``.
For more information on Groebner bases, see the references and the docstring
of `solve_poly_system()`.
Examples
========
Example taken from [1].
>>> from sympy import groebner
>>> from sympy.abc import x, y
>>> F = [x*y - 2*y, 2*y**2 - x**2]
>>> groebner(F, x, y, order='lex')
GroebnerBasis([x**2 - 2*y**2, x*y - 2*y, y**3 - 2*y], x, y,
domain='ZZ', order='lex')
>>> groebner(F, x, y, order='grlex')
GroebnerBasis([y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y], x, y,
domain='ZZ', order='grlex')
>>> groebner(F, x, y, order='grevlex')
GroebnerBasis([y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y], x, y,
domain='ZZ', order='grevlex')
By default, an improved implementation of the Buchberger algorithm is
used. Optionally, an implementation of the F5B algorithm can be used.
The algorithm can be set using ``method`` flag or with the :func:`setup`
function from :mod:`sympy.polys.polyconfig`:
>>> F = [x**2 - x - 1, (2*x - 1) * y - (x**10 - (1 - x)**10)]
>>> groebner(F, x, y, method='buchberger')
GroebnerBasis([x**2 - x - 1, y - 55], x, y, domain='ZZ', order='lex')
>>> groebner(F, x, y, method='f5b')
GroebnerBasis([x**2 - x - 1, y - 55], x, y, domain='ZZ', order='lex')
References
==========
1. [Buchberger01]_
2. [Cox97]_
"""
return GroebnerBasis(F, *gens, **args)
@public
def is_zero_dimensional(F, *gens, **args):
"""
Checks if the ideal generated by a Groebner basis is zero-dimensional.
The algorithm checks if the set of monomials not divisible by the
leading monomial of any element of ``F`` is bounded.
References
==========
David A. Cox, John B. Little, Donal O'Shea. Ideals, Varieties and
Algorithms, 3rd edition, p. 230
"""
return GroebnerBasis(F, *gens, **args).is_zero_dimensional
@public
class GroebnerBasis(Basic):
"""Represents a reduced Groebner basis. """
def __new__(cls, F, *gens, **args):
"""Compute a reduced Groebner basis for a system of polynomials. """
options.allowed_flags(args, ['polys', 'method'])
try:
polys, opt = parallel_poly_from_expr(F, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('groebner', len(F), exc)
from sympy.polys.rings import PolyRing
ring = PolyRing(opt.gens, opt.domain, opt.order)
polys = [ring.from_dict(poly.rep.to_dict()) for poly in polys if poly]
G = _groebner(polys, ring, method=opt.method)
G = [Poly._from_dict(g, opt) for g in G]
return cls._new(G, opt)
@classmethod
def _new(cls, basis, options):
obj = Basic.__new__(cls)
obj._basis = tuple(basis)
obj._options = options
return obj
@property
def args(self):
return (Tuple(*self._basis), Tuple(*self._options.gens))
@property
def exprs(self):
return [poly.as_expr() for poly in self._basis]
@property
def polys(self):
return list(self._basis)
@property
def gens(self):
return self._options.gens
@property
def domain(self):
return self._options.domain
@property
def order(self):
return self._options.order
def __len__(self):
return len(self._basis)
def __iter__(self):
if self._options.polys:
return iter(self.polys)
else:
return iter(self.exprs)
def __getitem__(self, item):
if self._options.polys:
basis = self.polys
else:
basis = self.exprs
return basis[item]
def __hash__(self):
return hash((self._basis, tuple(self._options.items())))
def __eq__(self, other):
if isinstance(other, self.__class__):
return self._basis == other._basis and self._options == other._options
elif iterable(other):
return self.polys == list(other) or self.exprs == list(other)
else:
return False
def __ne__(self, other):
return not self == other
@property
def is_zero_dimensional(self):
"""
Checks if the ideal generated by a Groebner basis is zero-dimensional.
The algorithm checks if the set of monomials not divisible by the
leading monomial of any element of ``F`` is bounded.
References
==========
David A. Cox, John B. Little, Donal O'Shea. Ideals, Varieties and
Algorithms, 3rd edition, p. 230
"""
def single_var(monomial):
return sum(map(bool, monomial)) == 1
exponents = Monomial([0]*len(self.gens))
order = self._options.order
for poly in self.polys:
monomial = poly.LM(order=order)
if single_var(monomial):
exponents *= monomial
# If any element of the exponents vector is zero, then there's
# a variable for which there's no degree bound and the ideal
# generated by this Groebner basis isn't zero-dimensional.
return all(exponents)
def fglm(self, order):
"""
Convert a Groebner basis from one ordering to another.
The FGLM algorithm converts reduced Groebner bases of zero-dimensional
ideals from one ordering to another. This method is often used when it
is infeasible to compute a Groebner basis with respect to a particular
ordering directly.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import groebner
>>> F = [x**2 - 3*y - x + 1, y**2 - 2*x + y - 1]
>>> G = groebner(F, x, y, order='grlex')
>>> list(G.fglm('lex'))
[2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7]
>>> list(groebner(F, x, y, order='lex'))
[2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7]
References
==========
J.C. Faugere, P. Gianni, D. Lazard, T. Mora (1994). Efficient
Computation of Zero-dimensional Groebner Bases by Change of
Ordering
"""
opt = self._options
src_order = opt.order
dst_order = monomial_key(order)
if src_order == dst_order:
return self
if not self.is_zero_dimensional:
raise NotImplementedError("can't convert Groebner bases of ideals with positive dimension")
polys = list(self._basis)
domain = opt.domain
opt = opt.clone(dict(
domain=domain.get_field(),
order=dst_order,
))
from sympy.polys.rings import xring
_ring, _ = xring(opt.gens, opt.domain, src_order)
for i, poly in enumerate(polys):
poly = poly.set_domain(opt.domain).rep.to_dict()
polys[i] = _ring.from_dict(poly)
G = matrix_fglm(polys, _ring, dst_order)
G = [Poly._from_dict(dict(g), opt) for g in G]
if not domain.is_Field:
G = [g.clear_denoms(convert=True)[1] for g in G]
opt.domain = domain
return self._new(G, opt)
def reduce(self, expr, auto=True):
"""
Reduces a polynomial modulo a Groebner basis.
Given a polynomial ``f`` and a set of polynomials ``G = (g_1, ..., g_n)``,
computes a set of quotients ``q = (q_1, ..., q_n)`` and the remainder ``r``
such that ``f = q_1*f_1 + ... + q_n*f_n + r``, where ``r`` vanishes or ``r``
is a completely reduced polynomial with respect to ``G``.
Examples
========
>>> from sympy import groebner, expand
>>> from sympy.abc import x, y
>>> f = 2*x**4 - x**2 + y**3 + y**2
>>> G = groebner([x**3 - x, y**3 - y])
>>> G.reduce(f)
([2*x, 1], x**2 + y**2 + y)
>>> Q, r = _
>>> expand(sum(q*g for q, g in zip(Q, G)) + r)
2*x**4 - x**2 + y**3 + y**2
>>> _ == f
True
"""
poly = Poly._from_expr(expr, self._options)
polys = [poly] + list(self._basis)
opt = self._options
domain = opt.domain
retract = False
if auto and domain.is_Ring and not domain.is_Field:
opt = opt.clone(dict(domain=domain.get_field()))
retract = True
from sympy.polys.rings import xring
_ring, _ = xring(opt.gens, opt.domain, opt.order)
for i, poly in enumerate(polys):
poly = poly.set_domain(opt.domain).rep.to_dict()
polys[i] = _ring.from_dict(poly)
Q, r = polys[0].div(polys[1:])
Q = [Poly._from_dict(dict(q), opt) for q in Q]
r = Poly._from_dict(dict(r), opt)
if retract:
try:
_Q, _r = [q.to_ring() for q in Q], r.to_ring()
except CoercionFailed:
pass
else:
Q, r = _Q, _r
if not opt.polys:
return [q.as_expr() for q in Q], r.as_expr()
else:
return Q, r
def contains(self, poly):
"""
Check if ``poly`` belongs the ideal generated by ``self``.
Examples
========
>>> from sympy import groebner
>>> from sympy.abc import x, y
>>> f = 2*x**3 + y**3 + 3*y
>>> G = groebner([x**2 + y**2 - 1, x*y - 2])
>>> G.contains(f)
True
>>> G.contains(f + 1)
False
"""
return self.reduce(poly)[1] == 0
@public
def poly(expr, *gens, **args):
"""
Efficiently transform an expression into a polynomial.
Examples
========
>>> from sympy import poly
>>> from sympy.abc import x
>>> poly(x*(x**2 + x - 1)**2)
Poly(x**5 + 2*x**4 - x**3 - 2*x**2 + x, x, domain='ZZ')
"""
options.allowed_flags(args, [])
def _poly(expr, opt):
terms, poly_terms = [], []
for term in Add.make_args(expr):
factors, poly_factors = [], []
for factor in Mul.make_args(term):
if factor.is_Add:
poly_factors.append(_poly(factor, opt))
elif factor.is_Pow and factor.base.is_Add and \
factor.exp.is_Integer and factor.exp >= 0:
poly_factors.append(
_poly(factor.base, opt).pow(factor.exp))
else:
factors.append(factor)
if not poly_factors:
terms.append(term)
else:
product = poly_factors[0]
for factor in poly_factors[1:]:
product = product.mul(factor)
if factors:
factor = Mul(*factors)
if factor.is_Number:
product = product.mul(factor)
else:
product = product.mul(Poly._from_expr(factor, opt))
poly_terms.append(product)
if not poly_terms:
result = Poly._from_expr(expr, opt)
else:
result = poly_terms[0]
for term in poly_terms[1:]:
result = result.add(term)
if terms:
term = Add(*terms)
if term.is_Number:
result = result.add(term)
else:
result = result.add(Poly._from_expr(term, opt))
return result.reorder(*opt.get('gens', ()), **args)
expr = sympify(expr)
if expr.is_Poly:
return Poly(expr, *gens, **args)
if 'expand' not in args:
args['expand'] = False
opt = options.build_options(gens, args)
return _poly(expr, opt)
|
2c776b17809de8ae5971e33a7fab7f46f069c146dfecc91fa394006b86be78ed
|
# -*- coding: utf-8 -*-
"""
This module contains functions for the computation
of Euclidean, (generalized) Sturmian, (modified) subresultant
polynomial remainder sequences (prs's) of two polynomials;
included are also three functions for the computation of the
resultant of two polynomials.
Except for the function res_z(), which computes the resultant
of two polynomials, the pseudo-remainder function prem()
of sympy is _not_ used by any of the functions in the module.
Instead of prem() we use the function
rem_z().
Included is also the function quo_z().
An explanation of why we avoid prem() can be found in the
references stated in the docstring of rem_z().
1. Theoretical background:
==========================
Consider the polynomials f, g ∈ Z[x] of degrees deg(f) = n and
deg(g) = m with n ≥ m.
Definition 1:
=============
The sign sequence of a polynomial remainder sequence (prs) is the
sequence of signs of the leading coefficients of its polynomials.
Sign sequences can be computed with the function:
sign_seq(poly_seq, x)
Definition 2:
=============
A polynomial remainder sequence (prs) is called complete if the
degree difference between any two consecutive polynomials is 1;
otherwise, it called incomplete.
It is understood that f, g belong to the sequences mentioned in
the two definitions above.
1A. Euclidean and subresultant prs's:
=====================================
The subresultant prs of f, g is a sequence of polynomials in Z[x]
analogous to the Euclidean prs, the sequence obtained by applying
on f, g Euclid’s algorithm for polynomial greatest common divisors
(gcd) in Q[x].
The subresultant prs differs from the Euclidean prs in that the
coefficients of each polynomial in the former sequence are determinants
--- also referred to as subresultants --- of appropriately selected
sub-matrices of sylvester1(f, g, x), Sylvester’s matrix of 1840 of
dimensions (n + m) × (n + m).
Recall that the determinant of sylvester1(f, g, x) itself is
called the resultant of f, g and serves as a criterion of whether
the two polynomials have common roots or not.
In sympy the resultant is computed with the function
resultant(f, g, x). This function does _not_ evaluate the
determinant of sylvester(f, g, x, 1); instead, it returns
the last member of the subresultant prs of f, g, multiplied
(if needed) by an appropriate power of -1; see the caveat below.
In this module we use three functions to compute the
resultant of f, g:
a) res(f, g, x) computes the resultant by evaluating
the determinant of sylvester(f, g, x, 1);
b) res_q(f, g, x) computes the resultant recursively, by
performing polynomial divisions in Q[x] with the function rem();
c) res_z(f, g, x) computes the resultant recursively, by
performing polynomial divisions in Z[x] with the function prem().
Caveat: If Df = degree(f, x) and Dg = degree(g, x), then:
resultant(f, g, x) = (-1)**(Df*Dg) * resultant(g, f, x).
For complete prs’s the sign sequence of the Euclidean prs of f, g
is identical to the sign sequence of the subresultant prs of f, g
and the coefficients of one sequence are easily computed from the
coefficients of the other.
For incomplete prs’s the polynomials in the subresultant prs, generally
differ in sign from those of the Euclidean prs, and --- unlike the
case of complete prs’s --- it is not at all obvious how to compute
the coefficients of one sequence from the coefficients of the other.
1B. Sturmian and modified subresultant prs's:
=============================================
For the same polynomials f, g ∈ Z[x] mentioned above, their ``modified''
subresultant prs is a sequence of polynomials similar to the Sturmian
prs, the sequence obtained by applying in Q[x] Sturm’s algorithm on f, g.
The two sequences differ in that the coefficients of each polynomial
in the modified subresultant prs are the determinants --- also referred
to as modified subresultants --- of appropriately selected sub-matrices
of sylvester2(f, g, x), Sylvester’s matrix of 1853 of dimensions 2n × 2n.
The determinant of sylvester2 itself is called the modified resultant
of f, g and it also can serve as a criterion of whether the two
polynomials have common roots or not.
For complete prs’s the sign sequence of the Sturmian prs of f, g is
identical to the sign sequence of the modified subresultant prs of
f, g and the coefficients of one sequence are easily computed from
the coefficients of the other.
For incomplete prs’s the polynomials in the modified subresultant prs,
generally differ in sign from those of the Sturmian prs, and --- unlike
the case of complete prs’s --- it is not at all obvious how to compute
the coefficients of one sequence from the coefficients of the other.
As Sylvester pointed out, the coefficients of the polynomial remainders
obtained as (modified) subresultants are the smallest possible without
introducing rationals and without computing (integer) greatest common
divisors.
1C. On terminology:
===================
Whence the terminology? Well generalized Sturmian prs's are
``modifications'' of Euclidean prs's; the hint came from the title
of the Pell-Gordon paper of 1917.
In the literature one also encounters the name ``non signed'' and
``signed'' prs for Euclidean and Sturmian prs respectively.
Likewise ``non signed'' and ``signed'' subresultant prs for
subresultant and modified subresultant prs respectively.
2. Functions in the module:
===========================
No function utilizes sympy's function prem().
2A. Matrices:
=============
The functions sylvester(f, g, x, method=1) and
sylvester(f, g, x, method=2) compute either Sylvester matrix.
They can be used to compute (modified) subresultant prs's by
direct determinant evaluation.
The function bezout(f, g, x, method='prs') provides a matrix of
smaller dimensions than either Sylvester matrix. It is the function
of choice for computing (modified) subresultant prs's by direct
determinant evaluation.
sylvester(f, g, x, method=1)
sylvester(f, g, x, method=2)
bezout(f, g, x, method='prs')
The following identity holds:
bezout(f, g, x, method='prs') =
backward_eye(deg(f))*bezout(f, g, x, method='bz')*backward_eye(deg(f))
2B. Subresultant and modified subresultant prs's by
===================================================
determinant evaluations:
=======================
We use the Sylvester matrices of 1840 and 1853 to
compute, respectively, subresultant and modified
subresultant polynomial remainder sequences. However,
for large matrices this approach takes a lot of time.
Instead of utilizing the Sylvester matrices, we can
employ the Bezout matrix which is of smaller dimensions.
subresultants_sylv(f, g, x)
modified_subresultants_sylv(f, g, x)
subresultants_bezout(f, g, x)
modified_subresultants_bezout(f, g, x)
2C. Subresultant prs's by ONE determinant evaluation:
=====================================================
All three functions in this section evaluate one determinant
per remainder polynomial; this is the determinant of an
appropriately selected sub-matrix of sylvester1(f, g, x),
Sylvester’s matrix of 1840.
To compute the remainder polynomials the function
subresultants_rem(f, g, x) employs rem(f, g, x).
By contrast, the other two functions implement Van Vleck’s ideas
of 1900 and compute the remainder polynomials by trinagularizing
sylvester2(f, g, x), Sylvester’s matrix of 1853.
subresultants_rem(f, g, x)
subresultants_vv(f, g, x)
subresultants_vv_2(f, g, x).
2E. Euclidean, Sturmian prs's in Q[x]:
======================================
euclid_q(f, g, x)
sturm_q(f, g, x)
2F. Euclidean, Sturmian and (modified) subresultant prs's P-G:
==============================================================
All functions in this section are based on the Pell-Gordon (P-G)
theorem of 1917.
Computations are done in Q[x], employing the function rem(f, g, x)
for the computation of the remainder polynomials.
euclid_pg(f, g, x)
sturm pg(f, g, x)
subresultants_pg(f, g, x)
modified_subresultants_pg(f, g, x)
2G. Euclidean, Sturmian and (modified) subresultant prs's A-M-V:
================================================================
All functions in this section are based on the Akritas-Malaschonok-
Vigklas (A-M-V) theorem of 2015.
Computations are done in Z[x], employing the function rem_z(f, g, x)
for the computation of the remainder polynomials.
euclid_amv(f, g, x)
sturm_amv(f, g, x)
subresultants_amv(f, g, x)
modified_subresultants_amv(f, g, x)
2Ga. Exception:
===============
subresultants_amv_q(f, g, x)
This function employs rem(f, g, x) for the computation of
the remainder polynomials, despite the fact that it implements
the A-M-V Theorem.
It is included in our module in order to show that theorems P-G
and A-M-V can be implemented utilizing either the function
rem(f, g, x) or the function rem_z(f, g, x).
For clearly historical reasons --- since the Collins-Brown-Traub
coefficients-reduction factor β_i was not available in 1917 ---
we have implemented the Pell-Gordon theorem with the function
rem(f, g, x) and the A-M-V Theorem with the function rem_z(f, g, x).
2H. Resultants:
===============
res(f, g, x)
res_q(f, g, x)
res_z(f, g, x)
"""
from __future__ import print_function, division
from sympy import (Abs, degree, expand, eye, floor, LC, Matrix, nan, Poly, pprint)
from sympy import (QQ, quo, prem, rem, S, sign, simplify, summation, var, zeros)
from sympy.polys.polyerrors import PolynomialError
def sylvester(f, g, x, method = 1):
'''
The input polynomials f, g are in Z[x] or in Q[x]. Let m = degree(f, x),
n = degree(g, x) and mx = max( m , n ).
a. If method = 1 (default), computes sylvester1, Sylvester's matrix of 1840
of dimension (m + n) x (m + n). The determinants of properly chosen
submatrices of this matrix (a.k.a. subresultants) can be
used to compute the coefficients of the Euclidean PRS of f, g.
b. If method = 2, computes sylvester2, Sylvester's matrix of 1853
of dimension (2*mx) x (2*mx). The determinants of properly chosen
submatrices of this matrix (a.k.a. ``modified'' subresultants) can be
used to compute the coefficients of the Sturmian PRS of f, g.
Applications of these Matrices can be found in the references below.
Especially, for applications of sylvester2, see the first reference!!
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On a Theorem
by Van Vleck Regarding Sturm Sequences. Serdica Journal of Computing,
Vol. 7, No 4, 101–134, 2013.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
'''
# obtain degrees of polys
m, n = degree( Poly(f, x), x), degree( Poly(g, x), x)
# Special cases:
# A:: case m = n < 0 (i.e. both polys are 0)
if m == n and n < 0:
return Matrix([])
# B:: case m = n = 0 (i.e. both polys are constants)
if m == n and n == 0:
return Matrix([])
# C:: m == 0 and n < 0 or m < 0 and n == 0
# (i.e. one poly is constant and the other is 0)
if m == 0 and n < 0:
return Matrix([])
elif m < 0 and n == 0:
return Matrix([])
# D:: m >= 1 and n < 0 or m < 0 and n >=1
# (i.e. one poly is of degree >=1 and the other is 0)
if m >= 1 and n < 0:
return Matrix([0])
elif m < 0 and n >= 1:
return Matrix([0])
fp = Poly(f, x).all_coeffs()
gp = Poly(g, x).all_coeffs()
# Sylvester's matrix of 1840 (default; a.k.a. sylvester1)
if method <= 1:
M = zeros(m + n)
k = 0
for i in range(n):
j = k
for coeff in fp:
M[i, j] = coeff
j = j + 1
k = k + 1
k = 0
for i in range(n, m + n):
j = k
for coeff in gp:
M[i, j] = coeff
j = j + 1
k = k + 1
return M
# Sylvester's matrix of 1853 (a.k.a sylvester2)
if method >= 2:
if len(fp) < len(gp):
h = []
for i in range(len(gp) - len(fp)):
h.append(0)
fp[ : 0] = h
else:
h = []
for i in range(len(fp) - len(gp)):
h.append(0)
gp[ : 0] = h
mx = max(m, n)
dim = 2*mx
M = zeros( dim )
k = 0
for i in range( mx ):
j = k
for coeff in fp:
M[2*i, j] = coeff
j = j + 1
j = k
for coeff in gp:
M[2*i + 1, j] = coeff
j = j + 1
k = k + 1
return M
def process_matrix_output(poly_seq, x):
"""
poly_seq is a polynomial remainder sequence computed either by
(modified_)subresultants_bezout or by (modified_)subresultants_sylv.
This function removes from poly_seq all zero polynomials as well
as all those whose degree is equal to the degree of a preceding
polynomial in poly_seq, as we scan it from left to right.
"""
L = poly_seq[:] # get a copy of the input sequence
d = degree(L[1], x)
i = 2
while i < len(L):
d_i = degree(L[i], x)
if d_i < 0: # zero poly
L.remove(L[i])
i = i - 1
if d == d_i: # poly degree equals degree of previous poly
L.remove(L[i])
i = i - 1
if d_i >= 0:
d = d_i
i = i + 1
return L
def subresultants_sylv(f, g, x):
"""
The input polynomials f, g are in Z[x] or in Q[x]. It is assumed
that deg(f) >= deg(g).
Computes the subresultant polynomial remainder sequence (prs)
of f, g by evaluating determinants of appropriately selected
submatrices of sylvester(f, g, x, 1). The dimensions of the
latter are (deg(f) + deg(g)) x (deg(f) + deg(g)).
Each coefficient is computed by evaluating the determinant of the
corresponding submatrix of sylvester(f, g, x, 1).
If the subresultant prs is complete, then the output coincides
with the Euclidean sequence of the polynomials f, g.
References:
===========
1. G.M.Diaz-Toca,L.Gonzalez-Vega: Various New Expressions for Subresultants
and Their Applications. Appl. Algebra in Engin., Communic. and Comp.,
Vol. 15, 233–266, 2004.
"""
# make sure neither f nor g is 0
if f == 0 or g == 0:
return [f, g]
n = degF = degree(f, x)
m = degG = degree(g, x)
# make sure proper degrees
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, degF, degG, f, g = m, n, degG, degF, g, f
if n > 0 and m == 0:
return [f, g]
SR_L = [f, g] # subresultant list
# form matrix sylvester(f, g, x, 1)
S = sylvester(f, g, x, 1)
# pick appropriate submatrices of S
# and form subresultant polys
j = m - 1
while j > 0:
Sp = S[:, :] # copy of S
# delete last j rows of coeffs of g
for ind in range(m + n - j, m + n):
Sp.row_del(m + n - j)
# delete last j rows of coeffs of f
for ind in range(m - j, m):
Sp.row_del(m - j)
# evaluate determinants and form coefficients list
coeff_L, k, l = [], Sp.rows, 0
while l <= j:
coeff_L.append(Sp[ : , 0 : k].det())
Sp.col_swap(k - 1, k + l)
l += 1
# form poly and append to SP_L
SR_L.append(Poly(coeff_L, x).as_expr())
j -= 1
# j = 0
SR_L.append(S.det())
return process_matrix_output(SR_L, x)
def modified_subresultants_sylv(f, g, x):
"""
The input polynomials f, g are in Z[x] or in Q[x]. It is assumed
that deg(f) >= deg(g).
Computes the modified subresultant polynomial remainder sequence (prs)
of f, g by evaluating determinants of appropriately selected
submatrices of sylvester(f, g, x, 2). The dimensions of the
latter are (2*deg(f)) x (2*deg(f)).
Each coefficient is computed by evaluating the determinant of the
corresponding submatrix of sylvester(f, g, x, 2).
If the modified subresultant prs is complete, then the output coincides
with the Sturmian sequence of the polynomials f, g.
References:
===========
1. A. G. Akritas,G.I. Malaschonok and P.S. Vigklas:
Sturm Sequences and Modified Subresultant Polynomial Remainder
Sequences. Serdica Journal of Computing, Vol. 8, No 1, 29--46, 2014.
"""
# make sure neither f nor g is 0
if f == 0 or g == 0:
return [f, g]
n = degF = degree(f, x)
m = degG = degree(g, x)
# make sure proper degrees
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, degF, degG, f, g = m, n, degG, degF, g, f
if n > 0 and m == 0:
return [f, g]
SR_L = [f, g] # modified subresultant list
# form matrix sylvester(f, g, x, 2)
S = sylvester(f, g, x, 2)
# pick appropriate submatrices of S
# and form modified subresultant polys
j = m - 1
while j > 0:
# delete last 2*j rows of pairs of coeffs of f, g
Sp = S[0:2*n - 2*j, :] # copy of first 2*n - 2*j rows of S
# evaluate determinants and form coefficients list
coeff_L, k, l = [], Sp.rows, 0
while l <= j:
coeff_L.append(Sp[ : , 0 : k].det())
Sp.col_swap(k - 1, k + l)
l += 1
# form poly and append to SP_L
SR_L.append(Poly(coeff_L, x).as_expr())
j -= 1
# j = 0
SR_L.append(S.det())
return process_matrix_output(SR_L, x)
def res(f, g, x):
"""
The input polynomials f, g are in Z[x] or in Q[x].
The output is the resultant of f, g computed by evaluating
the determinant of the matrix sylvester(f, g, x, 1).
References:
===========
1. J. S. Cohen: Computer Algebra and Symbolic Computation
- Mathematical Methods. A. K. Peters, 2003.
"""
if f == 0 or g == 0:
raise PolynomialError("The resultant of %s and %s is not defined" % (f, g))
else:
return sylvester(f, g, x, 1).det()
def res_q(f, g, x):
"""
The input polynomials f, g are in Z[x] or in Q[x].
The output is the resultant of f, g computed recursively
by polynomial divisions in Q[x], using the function rem.
See Cohen's book p. 281.
References:
===========
1. J. S. Cohen: Computer Algebra and Symbolic Computation
- Mathematical Methods. A. K. Peters, 2003.
"""
m = degree(f, x)
n = degree(g, x)
if m < n:
return (-1)**(m*n) * res_q(g, f, x)
elif n == 0: # g is a constant
return g**m
else:
r = rem(f, g, x)
if r == 0:
return 0
else:
s = degree(r, x)
l = LC(g, x)
return (-1)**(m*n) * l**(m-s)*res_q(g, r, x)
def res_z(f, g, x):
"""
The input polynomials f, g are in Z[x] or in Q[x].
The output is the resultant of f, g computed recursively
by polynomial divisions in Z[x], using the function prem().
See Cohen's book p. 283.
References:
===========
1. J. S. Cohen: Computer Algebra and Symbolic Computation
- Mathematical Methods. A. K. Peters, 2003.
"""
m = degree(f, x)
n = degree(g, x)
if m < n:
return (-1)**(m*n) * res_z(g, f, x)
elif n == 0: # g is a constant
return g**m
else:
r = prem(f, g, x)
if r == 0:
return 0
else:
delta = m - n + 1
w = (-1)**(m*n) * res_z(g, r, x)
s = degree(r, x)
l = LC(g, x)
k = delta * n - m + s
return quo(w, l**k, x)
def sign_seq(poly_seq, x):
"""
Given a sequence of polynomials poly_seq, it returns
the sequence of signs of the leading coefficients of
the polynomials in poly_seq.
"""
return [sign(LC(poly_seq[i], x)) for i in range(len(poly_seq))]
def bezout(p, q, x, method='bz'):
"""
The input polynomials p, q are in Z[x] or in Q[x]. Let
mx = max( degree(p, x) , degree(q, x) ).
The default option bezout(p, q, x, method='bz') returns Bezout's
symmetric matrix of p and q, of dimensions (mx) x (mx). The
determinant of this matrix is equal to the determinant of sylvester2,
Sylvester's matrix of 1853, whose dimensions are (2*mx) x (2*mx);
however the subresultants of these two matrices may differ.
The other option, bezout(p, q, x, 'prs'), is of interest to us
in this module because it returns a matrix equivalent to sylvester2.
In this case all subresultants of the two matrices are identical.
Both the subresultant polynomial remainder sequence (prs) and
the modified subresultant prs of p and q can be computed by
evaluating determinants of appropriately selected submatrices of
bezout(p, q, x, 'prs') --- one determinant per coefficient of the
remainder polynomials.
The matrices bezout(p, q, x, 'bz') and bezout(p, q, x, 'prs')
are related by the formula
bezout(p, q, x, 'prs') =
backward_eye(deg(p)) * bezout(p, q, x, 'bz') * backward_eye(deg(p)),
where backward_eye() is the backward identity function.
References
==========
1. G.M.Diaz-Toca,L.Gonzalez-Vega: Various New Expressions for Subresultants
and Their Applications. Appl. Algebra in Engin., Communic. and Comp.,
Vol. 15, 233–266, 2004.
"""
# obtain degrees of polys
m, n = degree( Poly(p, x), x), degree( Poly(q, x), x)
# Special cases:
# A:: case m = n < 0 (i.e. both polys are 0)
if m == n and n < 0:
return Matrix([])
# B:: case m = n = 0 (i.e. both polys are constants)
if m == n and n == 0:
return Matrix([])
# C:: m == 0 and n < 0 or m < 0 and n == 0
# (i.e. one poly is constant and the other is 0)
if m == 0 and n < 0:
return Matrix([])
elif m < 0 and n == 0:
return Matrix([])
# D:: m >= 1 and n < 0 or m < 0 and n >=1
# (i.e. one poly is of degree >=1 and the other is 0)
if m >= 1 and n < 0:
return Matrix([0])
elif m < 0 and n >= 1:
return Matrix([0])
y = var('y')
# expr is 0 when x = y
expr = p * q.subs({x:y}) - p.subs({x:y}) * q
# hence expr is exactly divisible by x - y
poly = Poly( quo(expr, x-y), x, y)
# form Bezout matrix and store them in B as indicated to get
# the LC coefficient of each poly either in the first position
# of each row (method='prs') or in the last (method='bz').
mx = max(m, n)
B = zeros(mx)
for i in range(mx):
for j in range(mx):
if method == 'prs':
B[mx - 1 - i, mx - 1 - j] = poly.nth(i, j)
else:
B[i, j] = poly.nth(i, j)
return B
def backward_eye(n):
'''
Returns the backward identity matrix of dimensions n x n.
Needed to "turn" the Bezout matrices
so that the leading coefficients are first.
See docstring of the function bezout(p, q, x, method='bz').
'''
M = eye(n) # identity matrix of order n
for i in range(int(M.rows / 2)):
M.row_swap(0 + i, M.rows - 1 - i)
return M
def subresultants_bezout(p, q, x):
"""
The input polynomials p, q are in Z[x] or in Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant polynomial remainder sequence
of p, q by evaluating determinants of appropriately selected
submatrices of bezout(p, q, x, 'prs'). The dimensions of the
latter are deg(p) x deg(p).
Each coefficient is computed by evaluating the determinant of the
corresponding submatrix of bezout(p, q, x, 'prs').
bezout(p, q, x, 'prs) is used instead of sylvester(p, q, x, 1),
Sylvester's matrix of 1840, because the dimensions of the latter
are (deg(p) + deg(q)) x (deg(p) + deg(q)).
If the subresultant prs is complete, then the output coincides
with the Euclidean sequence of the polynomials p, q.
References
==========
1. G.M.Diaz-Toca,L.Gonzalez-Vega: Various New Expressions for Subresultants
and Their Applications. Appl. Algebra in Engin., Communic. and Comp.,
Vol. 15, 233–266, 2004.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
f, g = p, q
n = degF = degree(f, x)
m = degG = degree(g, x)
# make sure proper degrees
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, degF, degG, f, g = m, n, degG, degF, g, f
if n > 0 and m == 0:
return [f, g]
SR_L = [f, g] # subresultant list
F = LC(f, x)**(degF - degG)
# form the bezout matrix
B = bezout(f, g, x, 'prs')
# pick appropriate submatrices of B
# and form subresultant polys
if degF > degG:
j = 2
if degF == degG:
j = 1
while j <= degF:
M = B[0:j, :]
k, coeff_L = j - 1, []
while k <= degF - 1:
coeff_L.append(M[: ,0 : j].det())
if k < degF - 1:
M.col_swap(j - 1, k + 1)
k = k + 1
# apply Theorem 2.1 in the paper by Toca & Vega 2004
# to get correct signs
SR_L.append((int((-1)**(j*(j-1)/2)) * Poly(coeff_L, x) / F).as_expr())
j = j + 1
return process_matrix_output(SR_L, x)
def modified_subresultants_bezout(p, q, x):
"""
The input polynomials p, q are in Z[x] or in Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the modified subresultant polynomial remainder sequence
of p, q by evaluating determinants of appropriately selected
submatrices of bezout(p, q, x, 'prs'). The dimensions of the
latter are deg(p) x deg(p).
Each coefficient is computed by evaluating the determinant of the
corresponding submatrix of bezout(p, q, x, 'prs').
bezout(p, q, x, 'prs') is used instead of sylvester(p, q, x, 2),
Sylvester's matrix of 1853, because the dimensions of the latter
are 2*deg(p) x 2*deg(p).
If the modified subresultant prs is complete, and LC( p ) > 0, the output
coincides with the (generalized) Sturm's sequence of the polynomials p, q.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
2. G.M.Diaz-Toca,L.Gonzalez-Vega: Various New Expressions for Subresultants
and Their Applications. Appl. Algebra in Engin., Communic. and Comp.,
Vol. 15, 233–266, 2004.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
f, g = p, q
n = degF = degree(f, x)
m = degG = degree(g, x)
# make sure proper degrees
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, degF, degG, f, g = m, n, degG, degF, g, f
if n > 0 and m == 0:
return [f, g]
SR_L = [f, g] # subresultant list
# form the bezout matrix
B = bezout(f, g, x, 'prs')
# pick appropriate submatrices of B
# and form subresultant polys
if degF > degG:
j = 2
if degF == degG:
j = 1
while j <= degF:
M = B[0:j, :]
k, coeff_L = j - 1, []
while k <= degF - 1:
coeff_L.append(M[: ,0 : j].det())
if k < degF - 1:
M.col_swap(j - 1, k + 1)
k = k + 1
## Theorem 2.1 in the paper by Toca & Vega 2004 is _not needed_
## in this case since
## the bezout matrix is equivalent to sylvester2
SR_L.append(( Poly(coeff_L, x)).as_expr())
j = j + 1
return process_matrix_output(SR_L, x)
def sturm_pg(p, q, x, method=0):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the (generalized) Sturm sequence of p and q in Z[x] or Q[x].
If q = diff(p, x, 1) it is the usual Sturm sequence.
A. If method == 0, default, the remainder coefficients of the sequence
are (in absolute value) ``modified'' subresultants, which for non-monic
polynomials are greater than the coefficients of the corresponding
subresultants by the factor Abs(LC(p)**( deg(p)- deg(q))).
B. If method == 1, the remainder coefficients of the sequence are (in
absolute value) subresultants, which for non-monic polynomials are
smaller than the coefficients of the corresponding ``modified''
subresultants by the factor Abs(LC(p)**( deg(p)- deg(q))).
If the Sturm sequence is complete, method=0 and LC( p ) > 0, the coefficients
of the polynomials in the sequence are ``modified'' subresultants.
That is, they are determinants of appropriately selected submatrices of
sylvester2, Sylvester's matrix of 1853. In this case the Sturm sequence
coincides with the ``modified'' subresultant prs, of the polynomials
p, q.
If the Sturm sequence is incomplete and method=0 then the signs of the
coefficients of the polynomials in the sequence may differ from the signs
of the coefficients of the corresponding polynomials in the ``modified''
subresultant prs; however, the absolute values are the same.
To compute the coefficients, no determinant evaluation takes place. Instead,
polynomial divisions in Q[x] are performed, using the function rem(p, q, x);
the coefficients of the remainders computed this way become (``modified'')
subresultants with the help of the Pell-Gordon Theorem of 1917.
See also the function euclid_pg(p, q, x).
References
==========
1. Pell A. J., R. L. Gordon. The Modified Remainders Obtained in Finding
the Highest Common Factor of Two Polynomials. Annals of MatheMatics,
Second Series, 18 (1917), No. 4, 188–193.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
d0 = degree(p, x)
d1 = degree(q, x)
if d0 == 0 and d1 == 0:
return [p, q]
if d1 > d0:
d0, d1 = d1, d0
p, q = q, p
if d0 > 0 and d1 == 0:
return [p,q]
# make sure LC(p) > 0
flag = 0
if LC(p,x) < 0:
flag = 1
p = -p
q = -q
# initialize
lcf = LC(p, x)**(d0 - d1) # lcf * subr = modified subr
a0, a1 = p, q # the input polys
sturm_seq = [a0, a1] # the output list
del0 = d0 - d1 # degree difference
rho1 = LC(a1, x) # leading coeff of a1
exp_deg = d1 - 1 # expected degree of a2
a2 = - rem(a0, a1, domain=QQ) # first remainder
rho2 = LC(a2,x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
deg_diff_new = exp_deg - d2 # expected - actual degree
del1 = d1 - d2 # degree difference
# mul_fac is the factor by which a2 is multiplied to
# get integer coefficients
mul_fac_old = rho1**(del0 + del1 - deg_diff_new)
# append accordingly
if method == 0:
sturm_seq.append( simplify(lcf * a2 * Abs(mul_fac_old)))
else:
sturm_seq.append( simplify( a2 * Abs(mul_fac_old)))
# main loop
deg_diff_old = deg_diff_new
while d2 > 0:
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
del0 = del1 # update degree difference
exp_deg = d1 - 1 # new expected degree
a2 = - rem(a0, a1, domain=QQ) # new remainder
rho3 = LC(a2, x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
deg_diff_new = exp_deg - d2 # expected - actual degree
del1 = d1 - d2 # degree difference
# take into consideration the power
# rho1**deg_diff_old that was "left out"
expo_old = deg_diff_old # rho1 raised to this power
expo_new = del0 + del1 - deg_diff_new # rho2 raised to this power
# update variables and append
mul_fac_new = rho2**(expo_new) * rho1**(expo_old) * mul_fac_old
deg_diff_old, mul_fac_old = deg_diff_new, mul_fac_new
rho1, rho2 = rho2, rho3
if method == 0:
sturm_seq.append( simplify(lcf * a2 * Abs(mul_fac_old)))
else:
sturm_seq.append( simplify( a2 * Abs(mul_fac_old)))
if flag: # change the sign of the sequence
sturm_seq = [-i for i in sturm_seq]
# gcd is of degree > 0 ?
m = len(sturm_seq)
if sturm_seq[m - 1] == nan or sturm_seq[m - 1] == 0:
sturm_seq.pop(m - 1)
return sturm_seq
def sturm_q(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the (generalized) Sturm sequence of p and q in Q[x].
Polynomial divisions in Q[x] are performed, using the function rem(p, q, x).
The coefficients of the polynomials in the Sturm sequence can be uniquely
determined from the corresponding coefficients of the polynomials found
either in:
(a) the ``modified'' subresultant prs, (references 1, 2)
or in
(b) the subresultant prs (reference 3).
References
==========
1. Pell A. J., R. L. Gordon. The Modified Remainders Obtained in Finding
the Highest Common Factor of Two Polynomials. Annals of MatheMatics,
Second Series, 18 (1917), No. 4, 188–193.
2 Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
3. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
d0 = degree(p, x)
d1 = degree(q, x)
if d0 == 0 and d1 == 0:
return [p, q]
if d1 > d0:
d0, d1 = d1, d0
p, q = q, p
if d0 > 0 and d1 == 0:
return [p,q]
# make sure LC(p) > 0
flag = 0
if LC(p,x) < 0:
flag = 1
p = -p
q = -q
# initialize
a0, a1 = p, q # the input polys
sturm_seq = [a0, a1] # the output list
a2 = -rem(a0, a1, domain=QQ) # first remainder
d2 = degree(a2, x) # degree of a2
sturm_seq.append( a2 )
# main loop
while d2 > 0:
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
a2 = -rem(a0, a1, domain=QQ) # new remainder
d2 = degree(a2, x) # actual degree of a2
sturm_seq.append( a2 )
if flag: # change the sign of the sequence
sturm_seq = [-i for i in sturm_seq]
# gcd is of degree > 0 ?
m = len(sturm_seq)
if sturm_seq[m - 1] == nan or sturm_seq[m - 1] == 0:
sturm_seq.pop(m - 1)
return sturm_seq
def sturm_amv(p, q, x, method=0):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the (generalized) Sturm sequence of p and q in Z[x] or Q[x].
If q = diff(p, x, 1) it is the usual Sturm sequence.
A. If method == 0, default, the remainder coefficients of the
sequence are (in absolute value) ``modified'' subresultants, which
for non-monic polynomials are greater than the coefficients of the
corresponding subresultants by the factor Abs(LC(p)**( deg(p)- deg(q))).
B. If method == 1, the remainder coefficients of the sequence are (in
absolute value) subresultants, which for non-monic polynomials are
smaller than the coefficients of the corresponding ``modified''
subresultants by the factor Abs( LC(p)**( deg(p)- deg(q)) ).
If the Sturm sequence is complete, method=0 and LC( p ) > 0, then the
coefficients of the polynomials in the sequence are ``modified'' subresultants.
That is, they are determinants of appropriately selected submatrices of
sylvester2, Sylvester's matrix of 1853. In this case the Sturm sequence
coincides with the ``modified'' subresultant prs, of the polynomials
p, q.
If the Sturm sequence is incomplete and method=0 then the signs of the
coefficients of the polynomials in the sequence may differ from the signs
of the coefficients of the corresponding polynomials in the ``modified''
subresultant prs; however, the absolute values are the same.
To compute the coefficients, no determinant evaluation takes place.
Instead, we first compute the euclidean sequence of p and q using
euclid_amv(p, q, x) and then: (a) change the signs of the remainders in the
Euclidean sequence according to the pattern "-, -, +, +, -, -, +, +,..."
(see Lemma 1 in the 1st reference or Theorem 3 in the 2nd reference)
and (b) if method=0, assuming deg(p) > deg(q), we multiply the remainder
coefficients of the Euclidean sequence times the factor
Abs( LC(p)**( deg(p)- deg(q)) ) to make them modified subresultants.
See also the function sturm_pg(p, q, x).
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On the Remainders
Obtained in Finding the Greatest Common Divisor of Two Polynomials.'' Serdica
Journal of Computing 9(2) (2015), 123-138.
3. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Subresultant Polynomial
Remainder Sequences Obtained by Polynomial Divisions in Q[x] or in Z[x].''
Serdica Journal of Computing 10 (2016), Νο.3-4, 197-217.
"""
# compute the euclidean sequence
prs = euclid_amv(p, q, x)
# defensive
if prs == [] or len(prs) == 2:
return prs
# the coefficients in prs are subresultants and hence are smaller
# than the corresponding subresultants by the factor
# Abs( LC(prs[0])**( deg(prs[0]) - deg(prs[1])) ); Theorem 2, 2nd reference.
lcf = Abs( LC(prs[0])**( degree(prs[0], x) - degree(prs[1], x) ) )
# the signs of the first two polys in the sequence stay the same
sturm_seq = [prs[0], prs[1]]
# change the signs according to "-, -, +, +, -, -, +, +,..."
# and multiply times lcf if needed
flag = 0
m = len(prs)
i = 2
while i <= m-1:
if flag == 0:
sturm_seq.append( - prs[i] )
i = i + 1
if i == m:
break
sturm_seq.append( - prs[i] )
i = i + 1
flag = 1
elif flag == 1:
sturm_seq.append( prs[i] )
i = i + 1
if i == m:
break
sturm_seq.append( prs[i] )
i = i + 1
flag = 0
# subresultants or modified subresultants?
if method == 0 and lcf > 1:
aux_seq = [sturm_seq[0], sturm_seq[1]]
for i in range(2, m):
aux_seq.append(simplify(sturm_seq[i] * lcf ))
sturm_seq = aux_seq
return sturm_seq
def euclid_pg(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the Euclidean sequence of p and q in Z[x] or Q[x].
If the Euclidean sequence is complete the coefficients of the polynomials
in the sequence are subresultants. That is, they are determinants of
appropriately selected submatrices of sylvester1, Sylvester's matrix of 1840.
In this case the Euclidean sequence coincides with the subresultant prs
of the polynomials p, q.
If the Euclidean sequence is incomplete the signs of the coefficients of the
polynomials in the sequence may differ from the signs of the coefficients of
the corresponding polynomials in the subresultant prs; however, the absolute
values are the same.
To compute the Euclidean sequence, no determinant evaluation takes place.
We first compute the (generalized) Sturm sequence of p and q using
sturm_pg(p, q, x, 1), in which case the coefficients are (in absolute value)
equal to subresultants. Then we change the signs of the remainders in the
Sturm sequence according to the pattern "-, -, +, +, -, -, +, +,..." ;
see Lemma 1 in the 1st reference or Theorem 3 in the 2nd reference as well as
the function sturm_pg(p, q, x).
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On the Remainders
Obtained in Finding the Greatest Common Divisor of Two Polynomials.'' Serdica
Journal of Computing 9(2) (2015), 123-138.
3. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Subresultant Polynomial
Remainder Sequences Obtained by Polynomial Divisions in Q[x] or in Z[x].''
Serdica Journal of Computing 10 (2016), Νο.3-4, 197-217.
"""
# compute the sturmian sequence using the Pell-Gordon (or AMV) theorem
# with the coefficients in the prs being (in absolute value) subresultants
prs = sturm_pg(p, q, x, 1) ## any other method would do
# defensive
if prs == [] or len(prs) == 2:
return prs
# the signs of the first two polys in the sequence stay the same
euclid_seq = [prs[0], prs[1]]
# change the signs according to "-, -, +, +, -, -, +, +,..."
flag = 0
m = len(prs)
i = 2
while i <= m-1:
if flag == 0:
euclid_seq.append(- prs[i] )
i = i + 1
if i == m:
break
euclid_seq.append(- prs[i] )
i = i + 1
flag = 1
elif flag == 1:
euclid_seq.append(prs[i] )
i = i + 1
if i == m:
break
euclid_seq.append(prs[i] )
i = i + 1
flag = 0
return euclid_seq
def euclid_q(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the Euclidean sequence of p and q in Q[x].
Polynomial divisions in Q[x] are performed, using the function rem(p, q, x).
The coefficients of the polynomials in the Euclidean sequence can be uniquely
determined from the corresponding coefficients of the polynomials found
either in:
(a) the ``modified'' subresultant polynomial remainder sequence,
(references 1, 2)
or in
(b) the subresultant polynomial remainder sequence (references 3).
References
==========
1. Pell A. J., R. L. Gordon. The Modified Remainders Obtained in Finding
the Highest Common Factor of Two Polynomials. Annals of MatheMatics,
Second Series, 18 (1917), No. 4, 188–193.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
3. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
d0 = degree(p, x)
d1 = degree(q, x)
if d0 == 0 and d1 == 0:
return [p, q]
if d1 > d0:
d0, d1 = d1, d0
p, q = q, p
if d0 > 0 and d1 == 0:
return [p,q]
# make sure LC(p) > 0
flag = 0
if LC(p,x) < 0:
flag = 1
p = -p
q = -q
# initialize
a0, a1 = p, q # the input polys
euclid_seq = [a0, a1] # the output list
a2 = rem(a0, a1, domain=QQ) # first remainder
d2 = degree(a2, x) # degree of a2
euclid_seq.append( a2 )
# main loop
while d2 > 0:
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
a2 = rem(a0, a1, domain=QQ) # new remainder
d2 = degree(a2, x) # actual degree of a2
euclid_seq.append( a2 )
if flag: # change the sign of the sequence
euclid_seq = [-i for i in euclid_seq]
# gcd is of degree > 0 ?
m = len(euclid_seq)
if euclid_seq[m - 1] == nan or euclid_seq[m - 1] == 0:
euclid_seq.pop(m - 1)
return euclid_seq
def euclid_amv(f, g, x):
"""
f, g are polynomials in Z[x] or Q[x]. It is assumed
that degree(f, x) >= degree(g, x).
Computes the Euclidean sequence of p and q in Z[x] or Q[x].
If the Euclidean sequence is complete the coefficients of the polynomials
in the sequence are subresultants. That is, they are determinants of
appropriately selected submatrices of sylvester1, Sylvester's matrix of 1840.
In this case the Euclidean sequence coincides with the subresultant prs,
of the polynomials p, q.
If the Euclidean sequence is incomplete the signs of the coefficients of the
polynomials in the sequence may differ from the signs of the coefficients of
the corresponding polynomials in the subresultant prs; however, the absolute
values are the same.
To compute the coefficients, no determinant evaluation takes place.
Instead, polynomial divisions in Z[x] or Q[x] are performed, using
the function rem_z(f, g, x); the coefficients of the remainders
computed this way become subresultants with the help of the
Collins-Brown-Traub formula for coefficient reduction.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Subresultant Polynomial
remainder Sequences Obtained by Polynomial Divisions in Q[x] or in Z[x].''
Serdica Journal of Computing 10 (2016), Νο.3-4, 197-217.
"""
# make sure neither f nor g is 0
if f == 0 or g == 0:
return [f, g]
# make sure proper degrees
d0 = degree(f, x)
d1 = degree(g, x)
if d0 == 0 and d1 == 0:
return [f, g]
if d1 > d0:
d0, d1 = d1, d0
f, g = g, f
if d0 > 0 and d1 == 0:
return [f, g]
# initialize
a0 = f
a1 = g
euclid_seq = [a0, a1]
deg_dif_p1, c = degree(a0, x) - degree(a1, x) + 1, -1
# compute the first polynomial of the prs
i = 1
a2 = rem_z(a0, a1, x) / Abs( (-1)**deg_dif_p1 ) # first remainder
euclid_seq.append( a2 )
d2 = degree(a2, x) # actual degree of a2
# main loop
while d2 >= 1:
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
i += 1
sigma0 = -LC(a0)
c = (sigma0**(deg_dif_p1 - 1)) / (c**(deg_dif_p1 - 2))
deg_dif_p1 = degree(a0, x) - d2 + 1
a2 = rem_z(a0, a1, x) / Abs( ((c**(deg_dif_p1 - 1)) * sigma0) )
euclid_seq.append( a2 )
d2 = degree(a2, x) # actual degree of a2
# gcd is of degree > 0 ?
m = len(euclid_seq)
if euclid_seq[m - 1] == nan or euclid_seq[m - 1] == 0:
euclid_seq.pop(m - 1)
return euclid_seq
def modified_subresultants_pg(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the ``modified'' subresultant prs of p and q in Z[x] or Q[x];
the coefficients of the polynomials in the sequence are
``modified'' subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester2, Sylvester's matrix of 1853.
To compute the coefficients, no determinant evaluation takes place. Instead,
polynomial divisions in Q[x] are performed, using the function rem(p, q, x);
the coefficients of the remainders computed this way become ``modified''
subresultants with the help of the Pell-Gordon Theorem of 1917.
If the ``modified'' subresultant prs is complete, and LC( p ) > 0, it coincides
with the (generalized) Sturm sequence of the polynomials p, q.
References
==========
1. Pell A. J., R. L. Gordon. The Modified Remainders Obtained in Finding
the Highest Common Factor of Two Polynomials. Annals of MatheMatics,
Second Series, 18 (1917), No. 4, 188–193.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
d0 = degree(p,x)
d1 = degree(q,x)
if d0 == 0 and d1 == 0:
return [p, q]
if d1 > d0:
d0, d1 = d1, d0
p, q = q, p
if d0 > 0 and d1 == 0:
return [p,q]
# initialize
k = var('k') # index in summation formula
u_list = [] # of elements (-1)**u_i
subres_l = [p, q] # mod. subr. prs output list
a0, a1 = p, q # the input polys
del0 = d0 - d1 # degree difference
degdif = del0 # save it
rho_1 = LC(a0) # lead. coeff (a0)
# Initialize Pell-Gordon variables
rho_list_minus_1 = sign( LC(a0, x)) # sign of LC(a0)
rho1 = LC(a1, x) # leading coeff of a1
rho_list = [ sign(rho1)] # of signs
p_list = [del0] # of degree differences
u = summation(k, (k, 1, p_list[0])) # value of u
u_list.append(u) # of u values
v = sum(p_list) # v value
# first remainder
exp_deg = d1 - 1 # expected degree of a2
a2 = - rem(a0, a1, domain=QQ) # first remainder
rho2 = LC(a2, x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
deg_diff_new = exp_deg - d2 # expected - actual degree
del1 = d1 - d2 # degree difference
# mul_fac is the factor by which a2 is multiplied to
# get integer coefficients
mul_fac_old = rho1**(del0 + del1 - deg_diff_new)
# update Pell-Gordon variables
p_list.append(1 + deg_diff_new) # deg_diff_new is 0 for complete seq
# apply Pell-Gordon formula (7) in second reference
num = 1 # numerator of fraction
for k in range(len(u_list)):
num *= (-1)**u_list[k]
num = num * (-1)**v
# denominator depends on complete / incomplete seq
if deg_diff_new == 0: # complete seq
den = 1
for k in range(len(rho_list)):
den *= rho_list[k]**(p_list[k] + p_list[k + 1])
den = den * rho_list_minus_1
else: # incomplete seq
den = 1
for k in range(len(rho_list)-1):
den *= rho_list[k]**(p_list[k] + p_list[k + 1])
den = den * rho_list_minus_1
expo = (p_list[len(rho_list) - 1] + p_list[len(rho_list)] - deg_diff_new)
den = den * rho_list[len(rho_list) - 1]**expo
# the sign of the determinant depends on sg(num / den)
if sign(num / den) > 0:
subres_l.append( simplify(rho_1**degdif*a2* Abs(mul_fac_old) ) )
else:
subres_l.append(- simplify(rho_1**degdif*a2* Abs(mul_fac_old) ) )
# update Pell-Gordon variables
k = var('k')
rho_list.append( sign(rho2))
u = summation(k, (k, 1, p_list[len(p_list) - 1]))
u_list.append(u)
v = sum(p_list)
deg_diff_old=deg_diff_new
# main loop
while d2 > 0:
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
del0 = del1 # update degree difference
exp_deg = d1 - 1 # new expected degree
a2 = - rem(a0, a1, domain=QQ) # new remainder
rho3 = LC(a2, x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
deg_diff_new = exp_deg - d2 # expected - actual degree
del1 = d1 - d2 # degree difference
# take into consideration the power
# rho1**deg_diff_old that was "left out"
expo_old = deg_diff_old # rho1 raised to this power
expo_new = del0 + del1 - deg_diff_new # rho2 raised to this power
mul_fac_new = rho2**(expo_new) * rho1**(expo_old) * mul_fac_old
# update variables
deg_diff_old, mul_fac_old = deg_diff_new, mul_fac_new
rho1, rho2 = rho2, rho3
# update Pell-Gordon variables
p_list.append(1 + deg_diff_new) # deg_diff_new is 0 for complete seq
# apply Pell-Gordon formula (7) in second reference
num = 1 # numerator
for k in range(len(u_list)):
num *= (-1)**u_list[k]
num = num * (-1)**v
# denominator depends on complete / incomplete seq
if deg_diff_new == 0: # complete seq
den = 1
for k in range(len(rho_list)):
den *= rho_list[k]**(p_list[k] + p_list[k + 1])
den = den * rho_list_minus_1
else: # incomplete seq
den = 1
for k in range(len(rho_list)-1):
den *= rho_list[k]**(p_list[k] + p_list[k + 1])
den = den * rho_list_minus_1
expo = (p_list[len(rho_list) - 1] + p_list[len(rho_list)] - deg_diff_new)
den = den * rho_list[len(rho_list) - 1]**expo
# the sign of the determinant depends on sg(num / den)
if sign(num / den) > 0:
subres_l.append( simplify(rho_1**degdif*a2* Abs(mul_fac_old) ) )
else:
subres_l.append(- simplify(rho_1**degdif*a2* Abs(mul_fac_old) ) )
# update Pell-Gordon variables
k = var('k')
rho_list.append( sign(rho2))
u = summation(k, (k, 1, p_list[len(p_list) - 1]))
u_list.append(u)
v = sum(p_list)
# gcd is of degree > 0 ?
m = len(subres_l)
if subres_l[m - 1] == nan or subres_l[m - 1] == 0:
subres_l.pop(m - 1)
# LC( p ) < 0
m = len(subres_l) # list may be shorter now due to deg(gcd ) > 0
if LC( p ) < 0:
aux_seq = [subres_l[0], subres_l[1]]
for i in range(2, m):
aux_seq.append(simplify(subres_l[i] * (-1) ))
subres_l = aux_seq
return subres_l
def subresultants_pg(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant prs of p and q in Z[x] or Q[x], from
the modified subresultant prs of p and q.
The coefficients of the polynomials in these two sequences differ only
in sign and the factor LC(p)**( deg(p)- deg(q)) as stated in
Theorem 2 of the reference.
The coefficients of the polynomials in the output sequence are
subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester1, Sylvester's matrix of 1840.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ‘‘On the Remainders
Obtained in Finding the Greatest Common Divisor of Two Polynomials.''
Serdica Journal of Computing 9(2) (2015), 123-138.
"""
# compute the modified subresultant prs
lst = modified_subresultants_pg(p,q,x) ## any other method would do
# defensive
if lst == [] or len(lst) == 2:
return lst
# the coefficients in lst are modified subresultants and, hence, are
# greater than those of the corresponding subresultants by the factor
# LC(lst[0])**( deg(lst[0]) - deg(lst[1])); see Theorem 2 in reference.
lcf = LC(lst[0])**( degree(lst[0], x) - degree(lst[1], x) )
# Initialize the subresultant prs list
subr_seq = [lst[0], lst[1]]
# compute the degree sequences m_i and j_i of Theorem 2 in reference.
deg_seq = [degree(Poly(poly, x), x) for poly in lst]
deg = deg_seq[0]
deg_seq_s = deg_seq[1:-1]
m_seq = [m-1 for m in deg_seq_s]
j_seq = [deg - m for m in m_seq]
# compute the AMV factors of Theorem 2 in reference.
fact = [(-1)**( j*(j-1)/S(2) ) for j in j_seq]
# shortened list without the first two polys
lst_s = lst[2:]
# poly lst_s[k] is multiplied times fact[k], divided by lcf
# and appended to the subresultant prs list
m = len(fact)
for k in range(m):
if sign(fact[k]) == -1:
subr_seq.append(-lst_s[k] / lcf)
else:
subr_seq.append(lst_s[k] / lcf)
return subr_seq
def subresultants_amv_q(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant prs of p and q in Q[x];
the coefficients of the polynomials in the sequence are
subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester1, Sylvester's matrix of 1840.
To compute the coefficients, no determinant evaluation takes place.
Instead, polynomial divisions in Q[x] are performed, using the
function rem(p, q, x); the coefficients of the remainders
computed this way become subresultants with the help of the
Akritas-Malaschonok-Vigklas Theorem of 2015.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Subresultant Polynomial
remainder Sequences Obtained by Polynomial Divisions in Q[x] or in Z[x].''
Serdica Journal of Computing 10 (2016), Νο.3-4, 197-217.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
d0 = degree(p, x)
d1 = degree(q, x)
if d0 == 0 and d1 == 0:
return [p, q]
if d1 > d0:
d0, d1 = d1, d0
p, q = q, p
if d0 > 0 and d1 == 0:
return [p, q]
# initialize
i, s = 0, 0 # counters for remainders & odd elements
p_odd_index_sum = 0 # contains the sum of p_1, p_3, etc
subres_l = [p, q] # subresultant prs output list
a0, a1 = p, q # the input polys
sigma1 = LC(a1, x) # leading coeff of a1
p0 = d0 - d1 # degree difference
if p0 % 2 == 1:
s += 1
phi = floor( (s + 1) / 2 )
mul_fac = 1
d2 = d1
# main loop
while d2 > 0:
i += 1
a2 = rem(a0, a1, domain= QQ) # new remainder
if i == 1:
sigma2 = LC(a2, x)
else:
sigma3 = LC(a2, x)
sigma1, sigma2 = sigma2, sigma3
d2 = degree(a2, x)
p1 = d1 - d2
psi = i + phi + p_odd_index_sum
# new mul_fac
mul_fac = sigma1**(p0 + 1) * mul_fac
## compute the sign of the first fraction in formula (9) of the paper
# numerator
num = (-1)**psi
# denominator
den = sign(mul_fac)
# the sign of the determinant depends on sign( num / den ) != 0
if sign(num / den) > 0:
subres_l.append( simplify(expand(a2* Abs(mul_fac))))
else:
subres_l.append(- simplify(expand(a2* Abs(mul_fac))))
## bring into mul_fac the missing power of sigma if there was a degree gap
if p1 - 1 > 0:
mul_fac = mul_fac * sigma1**(p1 - 1)
# update AMV variables
a0, a1, d0, d1 = a1, a2, d1, d2
p0 = p1
if p0 % 2 ==1:
s += 1
phi = floor( (s + 1) / 2 )
if i%2 == 1:
p_odd_index_sum += p0 # p_i has odd index
# gcd is of degree > 0 ?
m = len(subres_l)
if subres_l[m - 1] == nan or subres_l[m - 1] == 0:
subres_l.pop(m - 1)
return subres_l
def compute_sign(base, expo):
'''
base != 0 and expo >= 0 are integers;
returns the sign of base**expo without
evaluating the power itself!
'''
sb = sign(base)
if sb == 1:
return 1
pe = expo % 2
if pe == 0:
return -sb
else:
return sb
def rem_z(p, q, x):
'''
Intended mainly for p, q polynomials in Z[x] so that,
on dividing p by q, the remainder will also be in Z[x]. (However,
it also works fine for polynomials in Q[x].) It is assumed
that degree(p, x) >= degree(q, x).
It premultiplies p by the _absolute_ value of the leading coefficient
of q, raised to the power deg(p) - deg(q) + 1 and then performs
polynomial division in Q[x], using the function rem(p, q, x).
By contrast the function prem(p, q, x) does _not_ use the absolute
value of the leading coefficient of q.
This results not only in ``messing up the signs'' of the Euclidean and
Sturmian prs's as mentioned in the second reference,
but also in violation of the main results of the first and third
references --- Theorem 4 and Theorem 1 respectively. Theorems 4 and 1
establish a one-to-one correspondence between the Euclidean and the
Sturmian prs of p, q, on one hand, and the subresultant prs of p, q,
on the other.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On the Remainders
Obtained in Finding the Greatest Common Divisor of Two Polynomials.''
Serdica Journal of Computing, 9(2) (2015), 123-138.
2. http://planetMath.org/sturmstheorem
3. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result on
the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
'''
if (p.as_poly().is_univariate and q.as_poly().is_univariate and
p.as_poly().gens == q.as_poly().gens):
delta = (degree(p, x) - degree(q, x) + 1)
return rem(Abs(LC(q, x))**delta * p, q, x)
else:
return prem(p, q, x)
def quo_z(p, q, x):
"""
Intended mainly for p, q polynomials in Z[x] so that,
on dividing p by q, the quotient will also be in Z[x]. (However,
it also works fine for polynomials in Q[x].) It is assumed
that degree(p, x) >= degree(q, x).
It premultiplies p by the _absolute_ value of the leading coefficient
of q, raised to the power deg(p) - deg(q) + 1 and then performs
polynomial division in Q[x], using the function quo(p, q, x).
By contrast the function pquo(p, q, x) does _not_ use the absolute
value of the leading coefficient of q.
See also function rem_z(p, q, x) for additional comments and references.
"""
if (p.as_poly().is_univariate and q.as_poly().is_univariate and
p.as_poly().gens == q.as_poly().gens):
delta = (degree(p, x) - degree(q, x) + 1)
return quo(Abs(LC(q, x))**delta * p, q, x)
else:
return pquo(p, q, x)
def subresultants_amv(f, g, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(f, x) >= degree(g, x).
Computes the subresultant prs of p and q in Z[x] or Q[x];
the coefficients of the polynomials in the sequence are
subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester1, Sylvester's matrix of 1840.
To compute the coefficients, no determinant evaluation takes place.
Instead, polynomial divisions in Z[x] or Q[x] are performed, using
the function rem_z(p, q, x); the coefficients of the remainders
computed this way become subresultants with the help of the
Akritas-Malaschonok-Vigklas Theorem of 2015 and the Collins-Brown-
Traub formula for coefficient reduction.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``A Basic Result
on the Theory of Subresultants.'' Serdica Journal of Computing 10 (2016), Νο.1, 31-48.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Subresultant Polynomial
remainder Sequences Obtained by Polynomial Divisions in Q[x] or in Z[x].''
Serdica Journal of Computing 10 (2016), Νο.3-4, 197-217.
"""
# make sure neither f nor g is 0
if f == 0 or g == 0:
return [f, g]
# make sure proper degrees
d0 = degree(f, x)
d1 = degree(g, x)
if d0 == 0 and d1 == 0:
return [f, g]
if d1 > d0:
d0, d1 = d1, d0
f, g = g, f
if d0 > 0 and d1 == 0:
return [f, g]
# initialize
a0 = f
a1 = g
subres_l = [a0, a1]
deg_dif_p1, c = degree(a0, x) - degree(a1, x) + 1, -1
# initialize AMV variables
sigma1 = LC(a1, x) # leading coeff of a1
i, s = 0, 0 # counters for remainders & odd elements
p_odd_index_sum = 0 # contains the sum of p_1, p_3, etc
p0 = deg_dif_p1 - 1
if p0 % 2 == 1:
s += 1
phi = floor( (s + 1) / 2 )
# compute the first polynomial of the prs
i += 1
a2 = rem_z(a0, a1, x) / Abs( (-1)**deg_dif_p1 ) # first remainder
sigma2 = LC(a2, x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
p1 = d1 - d2 # degree difference
# sgn_den is the factor, the denominator 1st fraction of (9),
# by which a2 is multiplied to get integer coefficients
sgn_den = compute_sign( sigma1, p0 + 1 )
## compute sign of the 1st fraction in formula (9) of the paper
# numerator
psi = i + phi + p_odd_index_sum
num = (-1)**psi
# denominator
den = sgn_den
# the sign of the determinant depends on sign(num / den) != 0
if sign(num / den) > 0:
subres_l.append( a2 )
else:
subres_l.append( -a2 )
# update AMV variable
if p1 % 2 == 1:
s += 1
# bring in the missing power of sigma if there was gap
if p1 - 1 > 0:
sgn_den = sgn_den * compute_sign( sigma1, p1 - 1 )
# main loop
while d2 >= 1:
phi = floor( (s + 1) / 2 )
if i%2 == 1:
p_odd_index_sum += p1 # p_i has odd index
a0, a1, d0, d1 = a1, a2, d1, d2 # update polys and degrees
p0 = p1 # update degree difference
i += 1
sigma0 = -LC(a0)
c = (sigma0**(deg_dif_p1 - 1)) / (c**(deg_dif_p1 - 2))
deg_dif_p1 = degree(a0, x) - d2 + 1
a2 = rem_z(a0, a1, x) / Abs( ((c**(deg_dif_p1 - 1)) * sigma0) )
sigma3 = LC(a2, x) # leading coeff of a2
d2 = degree(a2, x) # actual degree of a2
p1 = d1 - d2 # degree difference
psi = i + phi + p_odd_index_sum
# update variables
sigma1, sigma2 = sigma2, sigma3
# new sgn_den
sgn_den = compute_sign( sigma1, p0 + 1 ) * sgn_den
# compute the sign of the first fraction in formula (9) of the paper
# numerator
num = (-1)**psi
# denominator
den = sgn_den
# the sign of the determinant depends on sign( num / den ) != 0
if sign(num / den) > 0:
subres_l.append( a2 )
else:
subres_l.append( -a2 )
# update AMV variable
if p1 % 2 ==1:
s += 1
# bring in the missing power of sigma if there was gap
if p1 - 1 > 0:
sgn_den = sgn_den * compute_sign( sigma1, p1 - 1 )
# gcd is of degree > 0 ?
m = len(subres_l)
if subres_l[m - 1] == nan or subres_l[m - 1] == 0:
subres_l.pop(m - 1)
return subres_l
def modified_subresultants_amv(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the modified subresultant prs of p and q in Z[x] or Q[x],
from the subresultant prs of p and q.
The coefficients of the polynomials in the two sequences differ only
in sign and the factor LC(p)**( deg(p)- deg(q)) as stated in
Theorem 2 of the reference.
The coefficients of the polynomials in the output sequence are
modified subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester2, Sylvester's matrix of 1853.
If the modified subresultant prs is complete, and LC( p ) > 0, it coincides
with the (generalized) Sturm's sequence of the polynomials p, q.
References
==========
1. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ‘‘On the Remainders
Obtained in Finding the Greatest Common Divisor of Two Polynomials.''
Serdica Journal of Computing, Serdica Journal of Computing, 9(2) (2015), 123-138.
"""
# compute the subresultant prs
lst = subresultants_amv(p,q,x) ## any other method would do
# defensive
if lst == [] or len(lst) == 2:
return lst
# the coefficients in lst are subresultants and, hence, smaller than those
# of the corresponding modified subresultants by the factor
# LC(lst[0])**( deg(lst[0]) - deg(lst[1])); see Theorem 2.
lcf = LC(lst[0])**( degree(lst[0], x) - degree(lst[1], x) )
# Initialize the modified subresultant prs list
subr_seq = [lst[0], lst[1]]
# compute the degree sequences m_i and j_i of Theorem 2
deg_seq = [degree(Poly(poly, x), x) for poly in lst]
deg = deg_seq[0]
deg_seq_s = deg_seq[1:-1]
m_seq = [m-1 for m in deg_seq_s]
j_seq = [deg - m for m in m_seq]
# compute the AMV factors of Theorem 2
fact = [(-1)**( j*(j-1)/S(2) ) for j in j_seq]
# shortened list without the first two polys
lst_s = lst[2:]
# poly lst_s[k] is multiplied times fact[k] and times lcf
# and appended to the subresultant prs list
m = len(fact)
for k in range(m):
if sign(fact[k]) == -1:
subr_seq.append( simplify(-lst_s[k] * lcf) )
else:
subr_seq.append( simplify(lst_s[k] * lcf) )
return subr_seq
def correct_sign(deg_f, deg_g, s1, rdel, cdel):
"""
Used in various subresultant prs algorithms.
Evaluates the determinant, (a.k.a. subresultant) of a properly selected
submatrix of s1, Sylvester's matrix of 1840, to get the correct sign
and value of the leading coefficient of a given polynomial remainder.
deg_f, deg_g are the degrees of the original polynomials p, q for which the
matrix s1 = sylvester(p, q, x, 1) was constructed.
rdel denotes the expected degree of the remainder; it is the number of
rows to be deleted from each group of rows in s1 as described in the
reference below.
cdel denotes the expected degree minus the actual degree of the remainder;
it is the number of columns to be deleted --- starting with the last column
forming the square matrix --- from the matrix resulting after the row deletions.
References
==========
Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``Sturm Sequences
and Modified Subresultant Polynomial Remainder Sequences.''
Serdica Journal of Computing, Vol. 8, No 1, 29–46, 2014.
"""
M = s1[:, :] # copy of matrix s1
# eliminate rdel rows from the first deg_g rows
for i in range(M.rows - deg_f - 1, M.rows - deg_f - rdel - 1, -1):
M.row_del(i)
# eliminate rdel rows from the last deg_f rows
for i in range(M.rows - 1, M.rows - rdel - 1, -1):
M.row_del(i)
# eliminate cdel columns
for i in range(cdel):
M.col_del(M.rows - 1)
# define submatrix
Md = M[:, 0: M.rows]
return Md.det()
def subresultants_rem(p, q, x):
"""
p, q are polynomials in Z[x] or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant prs of p and q in Z[x] or Q[x];
the coefficients of the polynomials in the sequence are
subresultants. That is, they are determinants of appropriately
selected submatrices of sylvester1, Sylvester's matrix of 1840.
To compute the coefficients polynomial divisions in Q[x] are
performed, using the function rem(p, q, x). The coefficients
of the remainders computed this way become subresultants by evaluating
one subresultant per remainder --- that of the leading coefficient.
This way we obtain the correct sign and value of the leading coefficient
of the remainder and we easily ``force'' the rest of the coefficients
to become subresultants.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
References
==========
1. Akritas, A. G.:``Three New Methods for Computing Subresultant
Polynomial Remainder Sequences (PRS’s).'' Serdica Journal of Computing 9(1) (2015), 1-26.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
f, g = p, q
n = deg_f = degree(f, x)
m = deg_g = degree(g, x)
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, deg_f, deg_g, f, g = m, n, deg_g, deg_f, g, f
if n > 0 and m == 0:
return [f, g]
# initialize
s1 = sylvester(f, g, x, 1)
sr_list = [f, g] # subresultant list
# main loop
while deg_g > 0:
r = rem(p, q, x)
d = degree(r, x)
if d < 0:
return sr_list
# make coefficients subresultants evaluating ONE determinant
exp_deg = deg_g - 1 # expected degree
sign_value = correct_sign(n, m, s1, exp_deg, exp_deg - d)
r = simplify((r / LC(r, x)) * sign_value)
# append poly with subresultant coeffs
sr_list.append(r)
# update degrees and polys
deg_f, deg_g = deg_g, d
p, q = q, r
# gcd is of degree > 0 ?
m = len(sr_list)
if sr_list[m - 1] == nan or sr_list[m - 1] == 0:
sr_list.pop(m - 1)
return sr_list
def pivot(M, i, j):
'''
M is a matrix, and M[i, j] specifies the pivot element.
All elements below M[i, j], in the j-th column, will
be zeroed, if they are not already 0, according to
Dodgson-Bareiss' integer preserving transformations.
References
==========
1. Akritas, A. G.: ``A new method for computing polynomial greatest
common divisors and polynomial remainder sequences.''
Numerische MatheMatik 52, 119-127, 1988.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On a Theorem
by Van Vleck Regarding Sturm Sequences.''
Serdica Journal of Computing, 7, No 4, 101–134, 2013.
'''
ma = M[:, :] # copy of matrix M
rs = ma.rows # No. of rows
cs = ma.cols # No. of cols
for r in range(i+1, rs):
if ma[r, j] != 0:
for c in range(j + 1, cs):
ma[r, c] = ma[i, j] * ma[r, c] - ma[i, c] * ma[r, j]
ma[r, j] = 0
return ma
def rotate_r(L, k):
'''
Rotates right by k. L is a row of a matrix or a list.
'''
ll = list(L)
if ll == []:
return []
for i in range(k):
el = ll.pop(len(ll) - 1)
ll.insert(0, el)
return ll if type(L) is list else Matrix([ll])
def rotate_l(L, k):
'''
Rotates left by k. L is a row of a matrix or a list.
'''
ll = list(L)
if ll == []:
return []
for i in range(k):
el = ll.pop(0)
ll.insert(len(ll) - 1, el)
return ll if type(L) is list else Matrix([ll])
def row2poly(row, deg, x):
'''
Converts the row of a matrix to a poly of degree deg and variable x.
Some entries at the beginning and/or at the end of the row may be zero.
'''
k = 0
poly = []
leng = len(row)
# find the beginning of the poly ; i.e. the first
# non-zero element of the row
while row[k] == 0:
k = k + 1
# append the next deg + 1 elements to poly
for j in range( deg + 1):
if k + j <= leng:
poly.append(row[k + j])
return Poly(poly, x)
def create_ma(deg_f, deg_g, row1, row2, col_num):
'''
Creates a ``small'' matrix M to be triangularized.
deg_f, deg_g are the degrees of the divident and of the
divisor polynomials respectively, deg_g > deg_f.
The coefficients of the divident poly are the elements
in row2 and those of the divisor poly are the elements
in row1.
col_num defines the number of columns of the matrix M.
'''
if deg_g - deg_f >= 1:
print('Reverse degrees')
return
m = zeros(deg_f - deg_g + 2, col_num)
for i in range(deg_f - deg_g + 1):
m[i, :] = rotate_r(row1, i)
m[deg_f - deg_g + 1, :] = row2
return m
def find_degree(M, deg_f):
'''
Finds the degree of the poly corresponding (after triangularization)
to the _last_ row of the ``small'' matrix M, created by create_ma().
deg_f is the degree of the divident poly.
If _last_ row is all 0's returns None.
'''
j = deg_f
for i in range(0, M.cols):
if M[M.rows - 1, i] == 0:
j = j - 1
else:
return j if j >= 0 else 0
def final_touches(s2, r, deg_g):
"""
s2 is sylvester2, r is the row pointer in s2,
deg_g is the degree of the poly last inserted in s2.
After a gcd of degree > 0 has been found with Van Vleck's
method, and was inserted into s2, if its last term is not
in the last column of s2, then it is inserted as many
times as needed, rotated right by one each time, until
the condition is met.
"""
R = s2.row(r-1)
# find the first non zero term
for i in range(s2.cols):
if R[0,i] == 0:
continue
else:
break
# missing rows until last term is in last column
mr = s2.cols - (i + deg_g + 1)
# insert them by replacing the existing entries in the row
i = 0
while mr != 0 and r + i < s2.rows :
s2[r + i, : ] = rotate_r(R, i + 1)
i += 1
mr -= 1
return s2
def subresultants_vv(p, q, x, method = 0):
"""
p, q are polynomials in Z[x] (intended) or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant prs of p, q by triangularizing,
in Z[x] or in Q[x], all the smaller matrices encountered in the
process of triangularizing sylvester2, Sylvester's matrix of 1853;
see references 1 and 2 for Van Vleck's method. With each remainder,
sylvester2 gets updated and is prepared to be printed if requested.
If sylvester2 has small dimensions and you want to see the final,
triangularized matrix use this version with method=1; otherwise,
use either this version with method=0 (default) or the faster version,
subresultants_vv_2(p, q, x), where sylvester2 is used implicitly.
Sylvester's matrix sylvester1 is also used to compute one
subresultant per remainder; namely, that of the leading
coefficient, in order to obtain the correct sign and to
force the remainder coefficients to become subresultants.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
If the final, triangularized matrix s2 is printed, then:
(a) if deg(p) - deg(q) > 1 or deg( gcd(p, q) ) > 0, several
of the last rows in s2 will remain unprocessed;
(b) if deg(p) - deg(q) == 0, p will not appear in the final matrix.
References
==========
1. Akritas, A. G.: ``A new method for computing polynomial greatest
common divisors and polynomial remainder sequences.''
Numerische MatheMatik 52, 119-127, 1988.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On a Theorem
by Van Vleck Regarding Sturm Sequences.''
Serdica Journal of Computing, 7, No 4, 101–134, 2013.
3. Akritas, A. G.:``Three New Methods for Computing Subresultant
Polynomial Remainder Sequences (PRS’s).'' Serdica Journal of Computing 9(1) (2015), 1-26.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
f, g = p, q
n = deg_f = degree(f, x)
m = deg_g = degree(g, x)
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, deg_f, deg_g, f, g = m, n, deg_g, deg_f, g, f
if n > 0 and m == 0:
return [f, g]
# initialize
s1 = sylvester(f, g, x, 1)
s2 = sylvester(f, g, x, 2)
sr_list = [f, g]
col_num = 2 * n # columns in s2
# make two rows (row0, row1) of poly coefficients
row0 = Poly(f, x, domain = QQ).all_coeffs()
leng0 = len(row0)
for i in range(col_num - leng0):
row0.append(0)
row0 = Matrix([row0])
row1 = Poly(g,x, domain = QQ).all_coeffs()
leng1 = len(row1)
for i in range(col_num - leng1):
row1.append(0)
row1 = Matrix([row1])
# row pointer for deg_f - deg_g == 1; may be reset below
r = 2
# modify first rows of s2 matrix depending on poly degrees
if deg_f - deg_g > 1:
r = 1
# replacing the existing entries in the rows of s2,
# insert row0 (deg_f - deg_g - 1) times, rotated each time
for i in range(deg_f - deg_g - 1):
s2[r + i, : ] = rotate_r(row0, i + 1)
r = r + deg_f - deg_g - 1
# insert row1 (deg_f - deg_g) times, rotated each time
for i in range(deg_f - deg_g):
s2[r + i, : ] = rotate_r(row1, r + i)
r = r + deg_f - deg_g
if deg_f - deg_g == 0:
r = 0
# main loop
while deg_g > 0:
# create a small matrix M, and triangularize it;
M = create_ma(deg_f, deg_g, row1, row0, col_num)
# will need only the first and last rows of M
for i in range(deg_f - deg_g + 1):
M1 = pivot(M, i, i)
M = M1[:, :]
# treat last row of M as poly; find its degree
d = find_degree(M, deg_f)
if d == None:
break
exp_deg = deg_g - 1
# evaluate one determinant & make coefficients subresultants
sign_value = correct_sign(n, m, s1, exp_deg, exp_deg - d)
poly = row2poly(M[M.rows - 1, :], d, x)
temp2 = LC(poly, x)
poly = simplify((poly / temp2) * sign_value)
# update s2 by inserting first row of M as needed
row0 = M[0, :]
for i in range(deg_g - d):
s2[r + i, :] = rotate_r(row0, r + i)
r = r + deg_g - d
# update s2 by inserting last row of M as needed
row1 = rotate_l(M[M.rows - 1, :], deg_f - d)
row1 = (row1 / temp2) * sign_value
for i in range(deg_g - d):
s2[r + i, :] = rotate_r(row1, r + i)
r = r + deg_g - d
# update degrees
deg_f, deg_g = deg_g, d
# append poly with subresultant coeffs
sr_list.append(poly)
# final touches to print the s2 matrix
if method != 0 and s2.rows > 2:
s2 = final_touches(s2, r, deg_g)
pprint(s2)
elif method != 0 and s2.rows == 2:
s2[1, :] = rotate_r(s2.row(1), 1)
pprint(s2)
return sr_list
def subresultants_vv_2(p, q, x):
"""
p, q are polynomials in Z[x] (intended) or Q[x]. It is assumed
that degree(p, x) >= degree(q, x).
Computes the subresultant prs of p, q by triangularizing,
in Z[x] or in Q[x], all the smaller matrices encountered in the
process of triangularizing sylvester2, Sylvester's matrix of 1853;
see references 1 and 2 for Van Vleck's method.
If the sylvester2 matrix has big dimensions use this version,
where sylvester2 is used implicitly. If you want to see the final,
triangularized matrix sylvester2, then use the first version,
subresultants_vv(p, q, x, 1).
sylvester1, Sylvester's matrix of 1840, is also used to compute
one subresultant per remainder; namely, that of the leading
coefficient, in order to obtain the correct sign and to
``force'' the remainder coefficients to become subresultants.
If the subresultant prs is complete, then it coincides with the
Euclidean sequence of the polynomials p, q.
References
==========
1. Akritas, A. G.: ``A new method for computing polynomial greatest
common divisors and polynomial remainder sequences.''
Numerische MatheMatik 52, 119-127, 1988.
2. Akritas, A. G., G.I. Malaschonok and P.S. Vigklas: ``On a Theorem
by Van Vleck Regarding Sturm Sequences.''
Serdica Journal of Computing, 7, No 4, 101–134, 2013.
3. Akritas, A. G.:``Three New Methods for Computing Subresultant
Polynomial Remainder Sequences (PRS’s).'' Serdica Journal of Computing 9(1) (2015), 1-26.
"""
# make sure neither p nor q is 0
if p == 0 or q == 0:
return [p, q]
# make sure proper degrees
f, g = p, q
n = deg_f = degree(f, x)
m = deg_g = degree(g, x)
if n == 0 and m == 0:
return [f, g]
if n < m:
n, m, deg_f, deg_g, f, g = m, n, deg_g, deg_f, g, f
if n > 0 and m == 0:
return [f, g]
# initialize
s1 = sylvester(f, g, x, 1)
sr_list = [f, g] # subresultant list
col_num = 2 * n # columns in sylvester2
# make two rows (row0, row1) of poly coefficients
row0 = Poly(f, x, domain = QQ).all_coeffs()
leng0 = len(row0)
for i in range(col_num - leng0):
row0.append(0)
row0 = Matrix([row0])
row1 = Poly(g,x, domain = QQ).all_coeffs()
leng1 = len(row1)
for i in range(col_num - leng1):
row1.append(0)
row1 = Matrix([row1])
# main loop
while deg_g > 0:
# create a small matrix M, and triangularize it
M = create_ma(deg_f, deg_g, row1, row0, col_num)
for i in range(deg_f - deg_g + 1):
M1 = pivot(M, i, i)
M = M1[:, :]
# treat last row of M as poly; find its degree
d = find_degree(M, deg_f)
if d == None:
return sr_list
exp_deg = deg_g - 1
# evaluate one determinant & make coefficients subresultants
sign_value = correct_sign(n, m, s1, exp_deg, exp_deg - d)
poly = row2poly(M[M.rows - 1, :], d, x)
poly = simplify((poly / LC(poly, x)) * sign_value)
# append poly with subresultant coeffs
sr_list.append(poly)
# update degrees and rows
deg_f, deg_g = deg_g, d
row0 = row1
row1 = Poly(poly, x, domain = QQ).all_coeffs()
leng1 = len(row1)
for i in range(col_num - leng1):
row1.append(0)
row1 = Matrix([row1])
return sr_list
|
74b85588ced98c5df96e52ebe109b1ebfb65ae8619f4be9e9233c5d7c02126da
|
"""Useful utilities for higher level polynomial classes. """
from __future__ import print_function, division
from sympy.polys.polyerrors import PolynomialError, GeneratorsError
from sympy.polys.polyoptions import build_options
from sympy.core.exprtools import decompose_power, decompose_power_rat
from sympy.core import (S, Add, Mul, Pow, Expr,
expand_mul, expand_multinomial)
from sympy.core.compatibility import range
import re
_gens_order = {
'a': 301, 'b': 302, 'c': 303, 'd': 304,
'e': 305, 'f': 306, 'g': 307, 'h': 308,
'i': 309, 'j': 310, 'k': 311, 'l': 312,
'm': 313, 'n': 314, 'o': 315, 'p': 216,
'q': 217, 'r': 218, 's': 219, 't': 220,
'u': 221, 'v': 222, 'w': 223, 'x': 124,
'y': 125, 'z': 126,
}
_max_order = 1000
_re_gen = re.compile(r"^(.+?)(\d*)$")
def _nsort(roots, separated=False):
"""Sort the numerical roots putting the real roots first, then sorting
according to real and imaginary parts. If ``separated`` is True, then
the real and imaginary roots will be returned in two lists, respectively.
This routine tries to avoid issue 6137 by separating the roots into real
and imaginary parts before evaluation. In addition, the sorting will raise
an error if any computation cannot be done with precision.
"""
if not all(r.is_number for r in roots):
raise NotImplementedError
# see issue 6137:
# get the real part of the evaluated real and imaginary parts of each root
key = [[i.n(2).as_real_imag()[0] for i in r.as_real_imag()] for r in roots]
# make sure the parts were computed with precision
if any(i._prec == 1 for k in key for i in k):
raise NotImplementedError("could not compute root with precision")
# insert a key to indicate if the root has an imaginary part
key = [(1 if i else 0, r, i) for r, i in key]
key = sorted(zip(key, roots))
# return the real and imaginary roots separately if desired
if separated:
r = []
i = []
for (im, _, _), v in key:
if im:
i.append(v)
else:
r.append(v)
return r, i
_, roots = zip(*key)
return list(roots)
def _sort_gens(gens, **args):
"""Sort generators in a reasonably intelligent way. """
opt = build_options(args)
gens_order, wrt = {}, None
if opt is not None:
gens_order, wrt = {}, opt.wrt
for i, gen in enumerate(opt.sort):
gens_order[gen] = i + 1
def order_key(gen):
gen = str(gen)
if wrt is not None:
try:
return (-len(wrt) + wrt.index(gen), gen, 0)
except ValueError:
pass
name, index = _re_gen.match(gen).groups()
if index:
index = int(index)
else:
index = 0
try:
return ( gens_order[name], name, index)
except KeyError:
pass
try:
return (_gens_order[name], name, index)
except KeyError:
pass
return (_max_order, name, index)
try:
gens = sorted(gens, key=order_key)
except TypeError: # pragma: no cover
pass
return tuple(gens)
def _unify_gens(f_gens, g_gens):
"""Unify generators in a reasonably intelligent way. """
f_gens = list(f_gens)
g_gens = list(g_gens)
if f_gens == g_gens:
return tuple(f_gens)
gens, common, k = [], [], 0
for gen in f_gens:
if gen in g_gens:
common.append(gen)
for i, gen in enumerate(g_gens):
if gen in common:
g_gens[i], k = common[k], k + 1
for gen in common:
i = f_gens.index(gen)
gens.extend(f_gens[:i])
f_gens = f_gens[i + 1:]
i = g_gens.index(gen)
gens.extend(g_gens[:i])
g_gens = g_gens[i + 1:]
gens.append(gen)
gens.extend(f_gens)
gens.extend(g_gens)
return tuple(gens)
def _analyze_gens(gens):
"""Support for passing generators as `*gens` and `[gens]`. """
if len(gens) == 1 and hasattr(gens[0], '__iter__'):
return tuple(gens[0])
else:
return tuple(gens)
def _sort_factors(factors, **args):
"""Sort low-level factors in increasing 'complexity' order. """
def order_if_multiple_key(factor):
(f, n) = factor
return (len(f), n, f)
def order_no_multiple_key(f):
return (len(f), f)
if args.get('multiple', True):
return sorted(factors, key=order_if_multiple_key)
else:
return sorted(factors, key=order_no_multiple_key)
def _not_a_coeff(expr):
"""Do not treat NaN and infinities as valid polynomial coefficients. """
return expr in [S.NaN, S.Infinity, S.NegativeInfinity, S.ComplexInfinity]
def _parallel_dict_from_expr_if_gens(exprs, opt):
"""Transform expressions into a multinomial form given generators. """
k, indices = len(opt.gens), {}
for i, g in enumerate(opt.gens):
indices[g] = i
polys = []
for expr in exprs:
poly = {}
if expr.is_Equality:
expr = expr.lhs - expr.rhs
for term in Add.make_args(expr):
coeff, monom = [], [0]*k
for factor in Mul.make_args(term):
if not _not_a_coeff(factor) and factor.is_Number:
coeff.append(factor)
else:
try:
if opt.series is False:
base, exp = decompose_power(factor)
if exp < 0:
exp, base = -exp, Pow(base, -S.One)
else:
base, exp = decompose_power_rat(factor)
monom[indices[base]] = exp
except KeyError:
if not factor.free_symbols.intersection(opt.gens):
coeff.append(factor)
else:
raise PolynomialError("%s contains an element of "
"the set of generators." % factor)
monom = tuple(monom)
if monom in poly:
poly[monom] += Mul(*coeff)
else:
poly[monom] = Mul(*coeff)
polys.append(poly)
return polys, opt.gens
def _parallel_dict_from_expr_no_gens(exprs, opt):
"""Transform expressions into a multinomial form and figure out generators. """
if opt.domain is not None:
def _is_coeff(factor):
return factor in opt.domain
elif opt.extension is True:
def _is_coeff(factor):
return factor.is_algebraic
elif opt.greedy is not False:
def _is_coeff(factor):
return False
else:
def _is_coeff(factor):
return factor.is_number
gens, reprs = set([]), []
for expr in exprs:
terms = []
if expr.is_Equality:
expr = expr.lhs - expr.rhs
for term in Add.make_args(expr):
coeff, elements = [], {}
for factor in Mul.make_args(term):
if not _not_a_coeff(factor) and (factor.is_Number or _is_coeff(factor)):
coeff.append(factor)
else:
if opt.series is False:
base, exp = decompose_power(factor)
if exp < 0:
exp, base = -exp, Pow(base, -S.One)
else:
base, exp = decompose_power_rat(factor)
elements[base] = elements.setdefault(base, 0) + exp
gens.add(base)
terms.append((coeff, elements))
reprs.append(terms)
gens = _sort_gens(gens, opt=opt)
k, indices = len(gens), {}
for i, g in enumerate(gens):
indices[g] = i
polys = []
for terms in reprs:
poly = {}
for coeff, term in terms:
monom = [0]*k
for base, exp in term.items():
monom[indices[base]] = exp
monom = tuple(monom)
if monom in poly:
poly[monom] += Mul(*coeff)
else:
poly[monom] = Mul(*coeff)
polys.append(poly)
return polys, tuple(gens)
def _dict_from_expr_if_gens(expr, opt):
"""Transform an expression into a multinomial form given generators. """
(poly,), gens = _parallel_dict_from_expr_if_gens((expr,), opt)
return poly, gens
def _dict_from_expr_no_gens(expr, opt):
"""Transform an expression into a multinomial form and figure out generators. """
(poly,), gens = _parallel_dict_from_expr_no_gens((expr,), opt)
return poly, gens
def parallel_dict_from_expr(exprs, **args):
"""Transform expressions into a multinomial form. """
reps, opt = _parallel_dict_from_expr(exprs, build_options(args))
return reps, opt.gens
def _parallel_dict_from_expr(exprs, opt):
"""Transform expressions into a multinomial form. """
if opt.expand is not False:
exprs = [ expr.expand() for expr in exprs ]
if any(expr.is_commutative is False for expr in exprs):
raise PolynomialError('non-commutative expressions are not supported')
if opt.gens:
reps, gens = _parallel_dict_from_expr_if_gens(exprs, opt)
else:
reps, gens = _parallel_dict_from_expr_no_gens(exprs, opt)
return reps, opt.clone({'gens': gens})
def dict_from_expr(expr, **args):
"""Transform an expression into a multinomial form. """
rep, opt = _dict_from_expr(expr, build_options(args))
return rep, opt.gens
def _dict_from_expr(expr, opt):
"""Transform an expression into a multinomial form. """
if expr.is_commutative is False:
raise PolynomialError('non-commutative expressions are not supported')
def _is_expandable_pow(expr):
return (expr.is_Pow and expr.exp.is_positive and expr.exp.is_Integer
and expr.base.is_Add)
if opt.expand is not False:
if not isinstance(expr, Expr):
raise PolynomialError('expression must be of type Expr')
expr = expr.expand()
# TODO: Integrate this into expand() itself
while any(_is_expandable_pow(i) or i.is_Mul and
any(_is_expandable_pow(j) for j in i.args) for i in
Add.make_args(expr)):
expr = expand_multinomial(expr)
while any(i.is_Mul and any(j.is_Add for j in i.args) for i in Add.make_args(expr)):
expr = expand_mul(expr)
if opt.gens:
rep, gens = _dict_from_expr_if_gens(expr, opt)
else:
rep, gens = _dict_from_expr_no_gens(expr, opt)
return rep, opt.clone({'gens': gens})
def expr_from_dict(rep, *gens):
"""Convert a multinomial form into an expression. """
result = []
for monom, coeff in rep.items():
term = [coeff]
for g, m in zip(gens, monom):
if m:
term.append(Pow(g, m))
result.append(Mul(*term))
return Add(*result)
parallel_dict_from_basic = parallel_dict_from_expr
dict_from_basic = dict_from_expr
basic_from_dict = expr_from_dict
def _dict_reorder(rep, gens, new_gens):
"""Reorder levels using dict representation. """
gens = list(gens)
monoms = rep.keys()
coeffs = rep.values()
new_monoms = [ [] for _ in range(len(rep)) ]
used_indices = set()
for gen in new_gens:
try:
j = gens.index(gen)
used_indices.add(j)
for M, new_M in zip(monoms, new_monoms):
new_M.append(M[j])
except ValueError:
for new_M in new_monoms:
new_M.append(0)
for i, _ in enumerate(gens):
if i not in used_indices:
for monom in monoms:
if monom[i]:
raise GeneratorsError("unable to drop generators")
return map(tuple, new_monoms), coeffs
class PicklableWithSlots(object):
"""
Mixin class that allows to pickle objects with ``__slots__``.
Examples
========
First define a class that mixes :class:`PicklableWithSlots` in::
>>> from sympy.polys.polyutils import PicklableWithSlots
>>> class Some(PicklableWithSlots):
... __slots__ = ['foo', 'bar']
...
... def __init__(self, foo, bar):
... self.foo = foo
... self.bar = bar
To make :mod:`pickle` happy in doctest we have to use these hacks::
>>> from sympy.core.compatibility import builtins
>>> builtins.Some = Some
>>> from sympy.polys import polyutils
>>> polyutils.Some = Some
Next lets see if we can create an instance, pickle it and unpickle::
>>> some = Some('abc', 10)
>>> some.foo, some.bar
('abc', 10)
>>> from pickle import dumps, loads
>>> some2 = loads(dumps(some))
>>> some2.foo, some2.bar
('abc', 10)
"""
__slots__ = []
def __getstate__(self, cls=None):
if cls is None:
# This is the case for the instance that gets pickled
cls = self.__class__
d = {}
# Get all data that should be stored from super classes
for c in cls.__bases__:
if hasattr(c, "__getstate__"):
d.update(c.__getstate__(self, c))
# Get all information that should be stored from cls and return the dict
for name in cls.__slots__:
if hasattr(self, name):
d[name] = getattr(self, name)
return d
def __setstate__(self, d):
# All values that were pickled are now assigned to a fresh instance
for name, value in d.items():
try:
setattr(self, name, value)
except AttributeError: # This is needed in cases like Rational :> Half
pass
|
1238af0590a63f77653715d7610b2e2e2e6a4ea07198d5d6994d26b0379aa3de
|
"""Computational algebraic field theory. """
from __future__ import print_function, division
from sympy import (
S, Rational, AlgebraicNumber,
Add, Mul, sympify, Dummy, expand_mul, I, pi
)
from sympy.functions.elementary.exponential import exp
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.polys.polytools import (
Poly, PurePoly, sqf_norm, invert, factor_list, groebner, resultant,
degree, poly_from_expr, parallel_poly_from_expr, lcm
)
from sympy.polys.polyerrors import (
IsomorphismFailed,
CoercionFailed,
NotAlgebraic,
GeneratorsError,
)
from sympy.polys.rootoftools import CRootOf
from sympy.polys.specialpolys import cyclotomic_poly
from sympy.polys.polyutils import dict_from_expr, expr_from_dict
from sympy.polys.domains import ZZ, QQ
from sympy.polys.orthopolys import dup_chebyshevt
from sympy.polys.rings import ring
from sympy.polys.ring_series import rs_compose_add
from sympy.printing.lambdarepr import LambdaPrinter
from sympy.utilities import (
numbered_symbols, variations, lambdify, public, sift
)
from sympy.core.exprtools import Factors
from sympy.core.function import _mexpand
from sympy.simplify.radsimp import _split_gcd
from sympy.simplify.simplify import _is_sum_surds
from sympy.ntheory import sieve
from sympy.ntheory.factor_ import divisors
from mpmath import pslq, mp
from sympy.core.compatibility import reduce
from sympy.core.compatibility import range
def _choose_factor(factors, x, v, dom=QQ, prec=200, bound=5):
"""
Return a factor having root ``v``
It is assumed that one of the factors has root ``v``.
"""
if isinstance(factors[0], tuple):
factors = [f[0] for f in factors]
if len(factors) == 1:
return factors[0]
points = {x:v}
symbols = dom.symbols if hasattr(dom, 'symbols') else []
t = QQ(1, 10)
for n in range(bound**len(symbols)):
prec1 = 10
n_temp = n
for s in symbols:
points[s] = n_temp % bound
n_temp = n_temp // bound
while True:
candidates = []
eps = t**(prec1 // 2)
for f in factors:
if abs(f.as_expr().evalf(prec1, points)) < eps:
candidates.append(f)
if candidates:
factors = candidates
if len(factors) == 1:
return factors[0]
if prec1 > prec:
break
prec1 *= 2
raise NotImplementedError("multiple candidates for the minimal polynomial of %s" % v)
def _separate_sq(p):
"""
helper function for ``_minimal_polynomial_sq``
It selects a rational ``g`` such that the polynomial ``p``
consists of a sum of terms whose surds squared have gcd equal to ``g``
and a sum of terms with surds squared prime with ``g``;
then it takes the field norm to eliminate ``sqrt(g)``
See simplify.simplify.split_surds and polytools.sqf_norm.
Examples
========
>>> from sympy import sqrt
>>> from sympy.abc import x
>>> from sympy.polys.numberfields import _separate_sq
>>> p= -x + sqrt(2) + sqrt(3) + sqrt(7)
>>> p = _separate_sq(p); p
-x**2 + 2*sqrt(3)*x + 2*sqrt(7)*x - 2*sqrt(21) - 8
>>> p = _separate_sq(p); p
-x**4 + 4*sqrt(7)*x**3 - 32*x**2 + 8*sqrt(7)*x + 20
>>> p = _separate_sq(p); p
-x**8 + 48*x**6 - 536*x**4 + 1728*x**2 - 400
"""
from sympy.utilities.iterables import sift
def is_sqrt(expr):
return expr.is_Pow and expr.exp is S.Half
# p = c1*sqrt(q1) + ... + cn*sqrt(qn) -> a = [(c1, q1), .., (cn, qn)]
a = []
for y in p.args:
if not y.is_Mul:
if is_sqrt(y):
a.append((S.One, y**2))
elif y.is_Atom:
a.append((y, S.One))
elif y.is_Pow and y.exp.is_integer:
a.append((y, S.One))
else:
raise NotImplementedError
continue
T, F = sift(y.args, is_sqrt, binary=True)
a.append((Mul(*F), Mul(*T)**2))
a.sort(key=lambda z: z[1])
if a[-1][1] is S.One:
# there are no surds
return p
surds = [z for y, z in a]
for i in range(len(surds)):
if surds[i] != 1:
break
g, b1, b2 = _split_gcd(*surds[i:])
a1 = []
a2 = []
for y, z in a:
if z in b1:
a1.append(y*z**S.Half)
else:
a2.append(y*z**S.Half)
p1 = Add(*a1)
p2 = Add(*a2)
p = _mexpand(p1**2) - _mexpand(p2**2)
return p
def _minimal_polynomial_sq(p, n, x):
"""
Returns the minimal polynomial for the ``nth-root`` of a sum of surds
or ``None`` if it fails.
Parameters
==========
p : sum of surds
n : positive integer
x : variable of the returned polynomial
Examples
========
>>> from sympy.polys.numberfields import _minimal_polynomial_sq
>>> from sympy import sqrt
>>> from sympy.abc import x
>>> q = 1 + sqrt(2) + sqrt(3)
>>> _minimal_polynomial_sq(q, 3, x)
x**12 - 4*x**9 - 4*x**6 + 16*x**3 - 8
"""
from sympy.simplify.simplify import _is_sum_surds
p = sympify(p)
n = sympify(n)
r = _is_sum_surds(p)
if not n.is_Integer or not n > 0 or not _is_sum_surds(p):
return None
pn = p**Rational(1, n)
# eliminate the square roots
p -= x
while 1:
p1 = _separate_sq(p)
if p1 is p:
p = p1.subs({x:x**n})
break
else:
p = p1
# _separate_sq eliminates field extensions in a minimal way, so that
# if n = 1 then `p = constant*(minimal_polynomial(p))`
# if n > 1 it contains the minimal polynomial as a factor.
if n == 1:
p1 = Poly(p)
if p.coeff(x**p1.degree(x)) < 0:
p = -p
p = p.primitive()[1]
return p
# by construction `p` has root `pn`
# the minimal polynomial is the factor vanishing in x = pn
factors = factor_list(p)[1]
result = _choose_factor(factors, x, pn)
return result
def _minpoly_op_algebraic_element(op, ex1, ex2, x, dom, mp1=None, mp2=None):
"""
return the minimal polynomial for ``op(ex1, ex2)``
Parameters
==========
op : operation ``Add`` or ``Mul``
ex1, ex2 : expressions for the algebraic elements
x : indeterminate of the polynomials
dom: ground domain
mp1, mp2 : minimal polynomials for ``ex1`` and ``ex2`` or None
Examples
========
>>> from sympy import sqrt, Add, Mul, QQ
>>> from sympy.polys.numberfields import _minpoly_op_algebraic_element
>>> from sympy.abc import x, y
>>> p1 = sqrt(sqrt(2) + 1)
>>> p2 = sqrt(sqrt(2) - 1)
>>> _minpoly_op_algebraic_element(Mul, p1, p2, x, QQ)
x - 1
>>> q1 = sqrt(y)
>>> q2 = 1 / y
>>> _minpoly_op_algebraic_element(Add, q1, q2, x, QQ.frac_field(y))
x**2*y**2 - 2*x*y - y**3 + 1
References
==========
[1] https://en.wikipedia.org/wiki/Resultant
[2] I.M. Isaacs, Proc. Amer. Math. Soc. 25 (1970), 638
"Degrees of sums in a separable field extension".
"""
y = Dummy(str(x))
if mp1 is None:
mp1 = _minpoly_compose(ex1, x, dom)
if mp2 is None:
mp2 = _minpoly_compose(ex2, y, dom)
else:
mp2 = mp2.subs({x: y})
if op is Add:
# mp1a = mp1.subs({x: x - y})
if dom == QQ:
R, X = ring('X', QQ)
p1 = R(dict_from_expr(mp1)[0])
p2 = R(dict_from_expr(mp2)[0])
else:
(p1, p2), _ = parallel_poly_from_expr((mp1, x - y), x, y)
r = p1.compose(p2)
mp1a = r.as_expr()
elif op is Mul:
mp1a = _muly(mp1, x, y)
else:
raise NotImplementedError('option not available')
if op is Mul or dom != QQ:
r = resultant(mp1a, mp2, gens=[y, x])
else:
r = rs_compose_add(p1, p2)
r = expr_from_dict(r.as_expr_dict(), x)
deg1 = degree(mp1, x)
deg2 = degree(mp2, y)
if op is Mul and deg1 == 1 or deg2 == 1:
# if deg1 = 1, then mp1 = x - a; mp1a = x - y - a;
# r = mp2(x - a), so that `r` is irreducible
return r
r = Poly(r, x, domain=dom)
_, factors = r.factor_list()
res = _choose_factor(factors, x, op(ex1, ex2), dom)
return res.as_expr()
def _invertx(p, x):
"""
Returns ``expand_mul(x**degree(p, x)*p.subs(x, 1/x))``
"""
p1 = poly_from_expr(p, x)[0]
n = degree(p1)
a = [c * x**(n - i) for (i,), c in p1.terms()]
return Add(*a)
def _muly(p, x, y):
"""
Returns ``_mexpand(y**deg*p.subs({x:x / y}))``
"""
p1 = poly_from_expr(p, x)[0]
n = degree(p1)
a = [c * x**i * y**(n - i) for (i,), c in p1.terms()]
return Add(*a)
def _minpoly_pow(ex, pw, x, dom, mp=None):
"""
Returns ``minpoly(ex**pw, x)``
Parameters
==========
ex : algebraic element
pw : rational number
x : indeterminate of the polynomial
dom: ground domain
mp : minimal polynomial of ``p``
Examples
========
>>> from sympy import sqrt, QQ, Rational
>>> from sympy.polys.numberfields import _minpoly_pow, minpoly
>>> from sympy.abc import x, y
>>> p = sqrt(1 + sqrt(2))
>>> _minpoly_pow(p, 2, x, QQ)
x**2 - 2*x - 1
>>> minpoly(p**2, x)
x**2 - 2*x - 1
>>> _minpoly_pow(y, Rational(1, 3), x, QQ.frac_field(y))
x**3 - y
>>> minpoly(y**Rational(1, 3), x)
x**3 - y
"""
pw = sympify(pw)
if not mp:
mp = _minpoly_compose(ex, x, dom)
if not pw.is_rational:
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
if pw < 0:
if mp == x:
raise ZeroDivisionError('%s is zero' % ex)
mp = _invertx(mp, x)
if pw == -1:
return mp
pw = -pw
ex = 1/ex
y = Dummy(str(x))
mp = mp.subs({x: y})
n, d = pw.as_numer_denom()
res = Poly(resultant(mp, x**d - y**n, gens=[y]), x, domain=dom)
_, factors = res.factor_list()
res = _choose_factor(factors, x, ex**pw, dom)
return res.as_expr()
def _minpoly_add(x, dom, *a):
"""
returns ``minpoly(Add(*a), dom, x)``
"""
mp = _minpoly_op_algebraic_element(Add, a[0], a[1], x, dom)
p = a[0] + a[1]
for px in a[2:]:
mp = _minpoly_op_algebraic_element(Add, p, px, x, dom, mp1=mp)
p = p + px
return mp
def _minpoly_mul(x, dom, *a):
"""
returns ``minpoly(Mul(*a), dom, x)``
"""
mp = _minpoly_op_algebraic_element(Mul, a[0], a[1], x, dom)
p = a[0] * a[1]
for px in a[2:]:
mp = _minpoly_op_algebraic_element(Mul, p, px, x, dom, mp1=mp)
p = p * px
return mp
def _minpoly_sin(ex, x):
"""
Returns the minimal polynomial of ``sin(ex)``
see http://mathworld.wolfram.com/TrigonometryAngles.html
"""
c, a = ex.args[0].as_coeff_Mul()
if a is pi:
if c.is_rational:
n = c.q
q = sympify(n)
if q.is_prime:
# for a = pi*p/q with q odd prime, using chebyshevt
# write sin(q*a) = mp(sin(a))*sin(a);
# the roots of mp(x) are sin(pi*p/q) for p = 1,..., q - 1
a = dup_chebyshevt(n, ZZ)
return Add(*[x**(n - i - 1)*a[i] for i in range(n)])
if c.p == 1:
if q == 9:
return 64*x**6 - 96*x**4 + 36*x**2 - 3
if n % 2 == 1:
# for a = pi*p/q with q odd, use
# sin(q*a) = 0 to see that the minimal polynomial must be
# a factor of dup_chebyshevt(n, ZZ)
a = dup_chebyshevt(n, ZZ)
a = [x**(n - i)*a[i] for i in range(n + 1)]
r = Add(*a)
_, factors = factor_list(r)
res = _choose_factor(factors, x, ex)
return res
expr = ((1 - cos(2*c*pi))/2)**S.Half
res = _minpoly_compose(expr, x, QQ)
return res
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
def _minpoly_cos(ex, x):
"""
Returns the minimal polynomial of ``cos(ex)``
see http://mathworld.wolfram.com/TrigonometryAngles.html
"""
from sympy import sqrt
c, a = ex.args[0].as_coeff_Mul()
if a is pi:
if c.is_rational:
if c.p == 1:
if c.q == 7:
return 8*x**3 - 4*x**2 - 4*x + 1
if c.q == 9:
return 8*x**3 - 6*x + 1
elif c.p == 2:
q = sympify(c.q)
if q.is_prime:
s = _minpoly_sin(ex, x)
return _mexpand(s.subs({x:sqrt((1 - x)/2)}))
# for a = pi*p/q, cos(q*a) =T_q(cos(a)) = (-1)**p
n = int(c.q)
a = dup_chebyshevt(n, ZZ)
a = [x**(n - i)*a[i] for i in range(n + 1)]
r = Add(*a) - (-1)**c.p
_, factors = factor_list(r)
res = _choose_factor(factors, x, ex)
return res
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
def _minpoly_exp(ex, x):
"""
Returns the minimal polynomial of ``exp(ex)``
"""
c, a = ex.args[0].as_coeff_Mul()
p = sympify(c.p)
q = sympify(c.q)
if a == I*pi:
if c.is_rational:
if c.p == 1 or c.p == -1:
if q == 3:
return x**2 - x + 1
if q == 4:
return x**4 + 1
if q == 6:
return x**4 - x**2 + 1
if q == 8:
return x**8 + 1
if q == 9:
return x**6 - x**3 + 1
if q == 10:
return x**8 - x**6 + x**4 - x**2 + 1
if q.is_prime:
s = 0
for i in range(q):
s += (-x)**i
return s
# x**(2*q) = product(factors)
factors = [cyclotomic_poly(i, x) for i in divisors(2*q)]
mp = _choose_factor(factors, x, ex)
return mp
else:
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
def _minpoly_rootof(ex, x):
"""
Returns the minimal polynomial of a ``CRootOf`` object.
"""
p = ex.expr
p = p.subs({ex.poly.gens[0]:x})
_, factors = factor_list(p, x)
result = _choose_factor(factors, x, ex)
return result
def _minpoly_compose(ex, x, dom):
"""
Computes the minimal polynomial of an algebraic element
using operations on minimal polynomials
Examples
========
>>> from sympy import minimal_polynomial, sqrt, Rational
>>> from sympy.abc import x, y
>>> minimal_polynomial(sqrt(2) + 3*Rational(1, 3), x, compose=True)
x**2 - 2*x - 1
>>> minimal_polynomial(sqrt(y) + 1/y, x, compose=True)
x**2*y**2 - 2*x*y - y**3 + 1
"""
if ex.is_Rational:
return ex.q*x - ex.p
if ex is I:
_, factors = factor_list(x**2 + 1, x, domain=dom)
return x**2 + 1 if len(factors) == 1 else x - I
if hasattr(dom, 'symbols') and ex in dom.symbols:
return x - ex
if dom.is_QQ and _is_sum_surds(ex):
# eliminate the square roots
ex -= x
while 1:
ex1 = _separate_sq(ex)
if ex1 is ex:
return ex
else:
ex = ex1
if ex.is_Add:
res = _minpoly_add(x, dom, *ex.args)
elif ex.is_Mul:
f = Factors(ex).factors
r = sift(f.items(), lambda itx: itx[0].is_Rational and itx[1].is_Rational)
if r[True] and dom == QQ:
ex1 = Mul(*[bx**ex for bx, ex in r[False] + r[None]])
r1 = dict(r[True])
dens = [y.q for y in r1.values()]
lcmdens = reduce(lcm, dens, 1)
neg1 = S.NegativeOne
expn1 = r1.pop(neg1, S.Zero)
nums = [base**(y.p*lcmdens // y.q) for base, y in r1.items()]
ex2 = Mul(*nums)
mp1 = minimal_polynomial(ex1, x)
# use the fact that in SymPy canonicalization products of integers
# raised to rational powers are organized in relatively prime
# bases, and that in ``base**(n/d)`` a perfect power is
# simplified with the root
# Powers of -1 have to be treated separately to preserve sign.
mp2 = ex2.q*x**lcmdens - ex2.p*neg1**(expn1*lcmdens)
ex2 = neg1**expn1 * ex2**Rational(1, lcmdens)
res = _minpoly_op_algebraic_element(Mul, ex1, ex2, x, dom, mp1=mp1, mp2=mp2)
else:
res = _minpoly_mul(x, dom, *ex.args)
elif ex.is_Pow:
res = _minpoly_pow(ex.base, ex.exp, x, dom)
elif ex.__class__ is sin:
res = _minpoly_sin(ex, x)
elif ex.__class__ is cos:
res = _minpoly_cos(ex, x)
elif ex.__class__ is exp:
res = _minpoly_exp(ex, x)
elif ex.__class__ is CRootOf:
res = _minpoly_rootof(ex, x)
else:
raise NotAlgebraic("%s doesn't seem to be an algebraic element" % ex)
return res
@public
def minimal_polynomial(ex, x=None, compose=True, polys=False, domain=None):
"""
Computes the minimal polynomial of an algebraic element.
Parameters
==========
ex : Expr
Element or expression whose minimal polynomial is to be calculated.
x : Symbol, optional
Independent variable of the minimal polynomial
compose : boolean, optional (default=True)
Method to use for computing minimal polynomial. If ``compose=True``
(default) then ``_minpoly_compose`` is used, if ``compose=False`` then
groebner bases are used.
polys : boolean, optional (default=False)
If ``True`` returns a ``Poly`` object else an ``Expr`` object.
domain : Domain, optional
Ground domain
Notes
=====
By default ``compose=True``, the minimal polynomial of the subexpressions of ``ex``
are computed, then the arithmetic operations on them are performed using the resultant
and factorization.
If ``compose=False``, a bottom-up algorithm is used with ``groebner``.
The default algorithm stalls less frequently.
If no ground domain is given, it will be generated automatically from the expression.
Examples
========
>>> from sympy import minimal_polynomial, sqrt, solve, QQ
>>> from sympy.abc import x, y
>>> minimal_polynomial(sqrt(2), x)
x**2 - 2
>>> minimal_polynomial(sqrt(2), x, domain=QQ.algebraic_field(sqrt(2)))
x - sqrt(2)
>>> minimal_polynomial(sqrt(2) + sqrt(3), x)
x**4 - 10*x**2 + 1
>>> minimal_polynomial(solve(x**3 + x + 3)[0], x)
x**3 + x + 3
>>> minimal_polynomial(sqrt(y), x)
x**2 - y
"""
from sympy.polys.polytools import degree
from sympy.polys.domains import FractionField
from sympy.core.basic import preorder_traversal
ex = sympify(ex)
if ex.is_number:
# not sure if it's always needed but try it for numbers (issue 8354)
ex = _mexpand(ex, recursive=True)
for expr in preorder_traversal(ex):
if expr.is_AlgebraicNumber:
compose = False
break
if x is not None:
x, cls = sympify(x), Poly
else:
x, cls = Dummy('x'), PurePoly
if not domain:
if ex.free_symbols:
domain = FractionField(QQ, list(ex.free_symbols))
else:
domain = QQ
if hasattr(domain, 'symbols') and x in domain.symbols:
raise GeneratorsError("the variable %s is an element of the ground "
"domain %s" % (x, domain))
if compose:
result = _minpoly_compose(ex, x, domain)
result = result.primitive()[1]
c = result.coeff(x**degree(result, x))
if c.is_negative:
result = expand_mul(-result)
return cls(result, x, field=True) if polys else result.collect(x)
if not domain.is_QQ:
raise NotImplementedError("groebner method only works for QQ")
result = _minpoly_groebner(ex, x, cls)
return cls(result, x, field=True) if polys else result.collect(x)
def _minpoly_groebner(ex, x, cls):
"""
Computes the minimal polynomial of an algebraic number
using Groebner bases
Examples
========
>>> from sympy import minimal_polynomial, sqrt, Rational
>>> from sympy.abc import x
>>> minimal_polynomial(sqrt(2) + 3*Rational(1, 3), x, compose=False)
x**2 - 2*x - 1
"""
from sympy.polys.polytools import degree
from sympy.core.function import expand_multinomial
generator = numbered_symbols('a', cls=Dummy)
mapping, symbols, replace = {}, {}, []
def update_mapping(ex, exp, base=None):
a = next(generator)
symbols[ex] = a
if base is not None:
mapping[ex] = a**exp + base
else:
mapping[ex] = exp.as_expr(a)
return a
def bottom_up_scan(ex):
if ex.is_Atom:
if ex is S.ImaginaryUnit:
if ex not in mapping:
return update_mapping(ex, 2, 1)
else:
return symbols[ex]
elif ex.is_Rational:
return ex
elif ex.is_Add:
return Add(*[ bottom_up_scan(g) for g in ex.args ])
elif ex.is_Mul:
return Mul(*[ bottom_up_scan(g) for g in ex.args ])
elif ex.is_Pow:
if ex.exp.is_Rational:
if ex.exp < 0 and ex.base.is_Add:
coeff, terms = ex.base.as_coeff_add()
elt, _ = primitive_element(terms, polys=True)
alg = ex.base - coeff
# XXX: turn this into eval()
inverse = invert(elt.gen + coeff, elt).as_expr()
base = inverse.subs(elt.gen, alg).expand()
if ex.exp == -1:
return bottom_up_scan(base)
else:
ex = base**(-ex.exp)
if not ex.exp.is_Integer:
base, exp = (
ex.base**ex.exp.p).expand(), Rational(1, ex.exp.q)
else:
base, exp = ex.base, ex.exp
base = bottom_up_scan(base)
expr = base**exp
if expr not in mapping:
return update_mapping(expr, 1/exp, -base)
else:
return symbols[expr]
elif ex.is_AlgebraicNumber:
if ex.root not in mapping:
return update_mapping(ex.root, ex.minpoly)
else:
return symbols[ex.root]
raise NotAlgebraic("%s doesn't seem to be an algebraic number" % ex)
def simpler_inverse(ex):
"""
Returns True if it is more likely that the minimal polynomial
algorithm works better with the inverse
"""
if ex.is_Pow:
if (1/ex.exp).is_integer and ex.exp < 0:
if ex.base.is_Add:
return True
if ex.is_Mul:
hit = True
a = []
for p in ex.args:
if p.is_Add:
return False
if p.is_Pow:
if p.base.is_Add and p.exp > 0:
return False
if hit:
return True
return False
inverted = False
ex = expand_multinomial(ex)
if ex.is_AlgebraicNumber:
return ex.minpoly.as_expr(x)
elif ex.is_Rational:
result = ex.q*x - ex.p
else:
inverted = simpler_inverse(ex)
if inverted:
ex = ex**-1
res = None
if ex.is_Pow and (1/ex.exp).is_Integer:
n = 1/ex.exp
res = _minimal_polynomial_sq(ex.base, n, x)
elif _is_sum_surds(ex):
res = _minimal_polynomial_sq(ex, S.One, x)
if res is not None:
result = res
if res is None:
bus = bottom_up_scan(ex)
F = [x - bus] + list(mapping.values())
G = groebner(F, list(symbols.values()) + [x], order='lex')
_, factors = factor_list(G[-1])
# by construction G[-1] has root `ex`
result = _choose_factor(factors, x, ex)
if inverted:
result = _invertx(result, x)
if result.coeff(x**degree(result, x)) < 0:
result = expand_mul(-result)
return result
minpoly = minimal_polynomial
__all__.append('minpoly')
def _coeffs_generator(n):
"""Generate coefficients for `primitive_element()`. """
for coeffs in variations([1, -1, 2, -2, 3, -3], n, repetition=True):
# Two linear combinations with coeffs of opposite signs are
# opposites of each other. Hence it suffices to test only one.
if coeffs[0] > 0:
yield list(coeffs)
@public
def primitive_element(extension, x=None, **args):
"""Construct a common number field for all extensions. """
if not extension:
raise ValueError("can't compute primitive element for empty extension")
if x is not None:
x, cls = sympify(x), Poly
else:
x, cls = Dummy('x'), PurePoly
if not args.get('ex', False):
gen, coeffs = extension[0], [1]
# XXX when minimal_polynomial is extended to work
# with AlgebraicNumbers this test can be removed
if isinstance(gen, AlgebraicNumber):
g = gen.minpoly.replace(x)
else:
g = minimal_polynomial(gen, x, polys=True)
for ext in extension[1:]:
_, factors = factor_list(g, extension=ext)
g = _choose_factor(factors, x, gen)
s, _, g = g.sqf_norm()
gen += s*ext
coeffs.append(s)
if not args.get('polys', False):
return g.as_expr(), coeffs
else:
return cls(g), coeffs
generator = numbered_symbols('y', cls=Dummy)
F, Y = [], []
for ext in extension:
y = next(generator)
if ext.is_Poly:
if ext.is_univariate:
f = ext.as_expr(y)
else:
raise ValueError("expected minimal polynomial, got %s" % ext)
else:
f = minpoly(ext, y)
F.append(f)
Y.append(y)
coeffs_generator = args.get('coeffs', _coeffs_generator)
for coeffs in coeffs_generator(len(Y)):
f = x - sum([ c*y for c, y in zip(coeffs, Y)])
G = groebner(F + [f], Y + [x], order='lex', field=True)
H, g = G[:-1], cls(G[-1], x, domain='QQ')
for i, (h, y) in enumerate(zip(H, Y)):
try:
H[i] = Poly(y - h, x,
domain='QQ').all_coeffs() # XXX: composite=False
except CoercionFailed: # pragma: no cover
break # G is not a triangular set
else:
break
else: # pragma: no cover
raise RuntimeError("run out of coefficient configurations")
_, g = g.clear_denoms()
if not args.get('polys', False):
return g.as_expr(), coeffs, H
else:
return g, coeffs, H
def is_isomorphism_possible(a, b):
"""Returns `True` if there is a chance for isomorphism. """
n = a.minpoly.degree()
m = b.minpoly.degree()
if m % n != 0:
return False
if n == m:
return True
da = a.minpoly.discriminant()
db = b.minpoly.discriminant()
i, k, half = 1, m//n, db//2
while True:
p = sieve[i]
P = p**k
if P > half:
break
if ((da % p) % 2) and not (db % P):
return False
i += 1
return True
def field_isomorphism_pslq(a, b):
"""Construct field isomorphism using PSLQ algorithm. """
if not a.root.is_real or not b.root.is_real:
raise NotImplementedError("PSLQ doesn't support complex coefficients")
f = a.minpoly
g = b.minpoly.replace(f.gen)
n, m, prev = 100, b.minpoly.degree(), None
for i in range(1, 5):
A = a.root.evalf(n)
B = b.root.evalf(n)
basis = [1, B] + [ B**i for i in range(2, m) ] + [A]
dps, mp.dps = mp.dps, n
coeffs = pslq(basis, maxcoeff=int(1e10), maxsteps=1000)
mp.dps = dps
if coeffs is None:
break
if coeffs != prev:
prev = coeffs
else:
break
coeffs = [S(c)/coeffs[-1] for c in coeffs[:-1]]
while not coeffs[-1]:
coeffs.pop()
coeffs = list(reversed(coeffs))
h = Poly(coeffs, f.gen, domain='QQ')
if f.compose(h).rem(g).is_zero:
d, approx = len(coeffs) - 1, 0
for i, coeff in enumerate(coeffs):
approx += coeff*B**(d - i)
if A*approx < 0:
return [ -c for c in coeffs ]
else:
return coeffs
elif f.compose(-h).rem(g).is_zero:
return [ -c for c in coeffs ]
else:
n *= 2
return None
def field_isomorphism_factor(a, b):
"""Construct field isomorphism via factorization. """
_, factors = factor_list(a.minpoly, extension=b)
for f, _ in factors:
if f.degree() == 1:
coeffs = f.rep.TC().to_sympy_list()
d, terms = len(coeffs) - 1, []
for i, coeff in enumerate(coeffs):
terms.append(coeff*b.root**(d - i))
root = Add(*terms)
if (a.root - root).evalf(chop=True) == 0:
return coeffs
if (a.root + root).evalf(chop=True) == 0:
return [ -c for c in coeffs ]
else:
return None
@public
def field_isomorphism(a, b, **args):
"""Construct an isomorphism between two number fields. """
a, b = sympify(a), sympify(b)
if not a.is_AlgebraicNumber:
a = AlgebraicNumber(a)
if not b.is_AlgebraicNumber:
b = AlgebraicNumber(b)
if a == b:
return a.coeffs()
n = a.minpoly.degree()
m = b.minpoly.degree()
if n == 1:
return [a.root]
if m % n != 0:
return None
if args.get('fast', True):
try:
result = field_isomorphism_pslq(a, b)
if result is not None:
return result
except NotImplementedError:
pass
return field_isomorphism_factor(a, b)
@public
def to_number_field(extension, theta=None, **args):
"""Express `extension` in the field generated by `theta`. """
gen = args.get('gen')
if hasattr(extension, '__iter__'):
extension = list(extension)
else:
extension = [extension]
if len(extension) == 1 and type(extension[0]) is tuple:
return AlgebraicNumber(extension[0])
minpoly, coeffs = primitive_element(extension, gen, polys=True)
root = sum([ coeff*ext for coeff, ext in zip(coeffs, extension) ])
if theta is None:
return AlgebraicNumber((minpoly, root))
else:
theta = sympify(theta)
if not theta.is_AlgebraicNumber:
theta = AlgebraicNumber(theta, gen=gen)
coeffs = field_isomorphism(root, theta)
if coeffs is not None:
return AlgebraicNumber(theta, coeffs)
else:
raise IsomorphismFailed(
"%s is not in a subfield of %s" % (root, theta.root))
class IntervalPrinter(LambdaPrinter):
"""Use ``lambda`` printer but print numbers as ``mpi`` intervals. """
def _print_Integer(self, expr):
return "mpi('%s')" % super(IntervalPrinter, self)._print_Integer(expr)
def _print_Rational(self, expr):
return "mpi('%s')" % super(IntervalPrinter, self)._print_Rational(expr)
def _print_Pow(self, expr):
return super(IntervalPrinter, self)._print_Pow(expr, rational=True)
@public
def isolate(alg, eps=None, fast=False):
"""Give a rational isolating interval for an algebraic number. """
alg = sympify(alg)
if alg.is_Rational:
return (alg, alg)
elif not alg.is_real:
raise NotImplementedError(
"complex algebraic numbers are not supported")
func = lambdify((), alg, modules="mpmath", printer=IntervalPrinter())
poly = minpoly(alg, polys=True)
intervals = poly.intervals(sqf=True)
dps, done = mp.dps, False
try:
while not done:
alg = func()
for a, b in intervals:
if a <= alg.a and alg.b <= b:
done = True
break
else:
mp.dps *= 2
finally:
mp.dps = dps
if eps is not None:
a, b = poly.refine_root(a, b, eps=eps, fast=fast)
return (a, b)
|
52a774f9153014dec8061dba238524ba42cf30b178a9af5613b187a46ef5e1b5
|
"""Utility functions for geometrical entities.
Contains
========
intersection
convex_hull
closest_points
farthest_points
are_coplanar
are_similar
"""
from __future__ import division, print_function
from sympy import Function, Symbol, solve
from sympy.core.compatibility import (
is_sequence, range, string_types, ordered)
from sympy.core.containers import OrderedSet
from .point import Point, Point2D
def find(x, equation):
"""
Checks whether the parameter 'x' is present in 'equation' or not.
If it is present then it returns the passed parameter 'x' as a free
symbol, else, it returns a ValueError.
"""
free = equation.free_symbols
xs = [i for i in free if (i.name if type(x) is str else i) == x]
if not xs:
raise ValueError('could not find %s' % x)
if len(xs) != 1:
raise ValueError('ambiguous %s' % x)
return xs[0]
def _ordered_points(p):
"""Return the tuple of points sorted numerically according to args"""
return tuple(sorted(p, key=lambda x: x.args))
def are_coplanar(*e):
""" Returns True if the given entities are coplanar otherwise False
Parameters
==========
e: entities to be checked for being coplanar
Returns
=======
Boolean
Examples
========
>>> from sympy import Point3D, Line3D
>>> from sympy.geometry.util import are_coplanar
>>> a = Line3D(Point3D(5, 0, 0), Point3D(1, -1, 1))
>>> b = Line3D(Point3D(0, -2, 0), Point3D(3, 1, 1))
>>> c = Line3D(Point3D(0, -1, 0), Point3D(5, -1, 9))
>>> are_coplanar(a, b, c)
False
"""
from sympy.geometry.line import LinearEntity3D
from sympy.geometry.point import Point3D
from sympy.geometry.plane import Plane
# XXX update tests for coverage
e = set(e)
# first work with a Plane if present
for i in list(e):
if isinstance(i, Plane):
e.remove(i)
return all(p.is_coplanar(i) for p in e)
if all(isinstance(i, Point3D) for i in e):
if len(e) < 3:
return False
# remove pts that are collinear with 2 pts
a, b = e.pop(), e.pop()
for i in list(e):
if Point3D.are_collinear(a, b, i):
e.remove(i)
if not e:
return False
else:
# define a plane
p = Plane(a, b, e.pop())
for i in e:
if i not in p:
return False
return True
else:
pt3d = []
for i in e:
if isinstance(i, Point3D):
pt3d.append(i)
elif isinstance(i, LinearEntity3D):
pt3d.extend(i.args)
elif isinstance(i, GeometryEntity): # XXX we should have a GeometryEntity3D class so we can tell the difference between 2D and 3D -- here we just want to deal with 2D objects; if new 3D objects are encountered that we didn't hanlde above, an error should be raised
# all 2D objects have some Point that defines them; so convert those points to 3D pts by making z=0
for p in i.args:
if isinstance(p, Point):
pt3d.append(Point3D(*(p.args + (0,))))
return are_coplanar(*pt3d)
def are_similar(e1, e2):
"""Are two geometrical entities similar.
Can one geometrical entity be uniformly scaled to the other?
Parameters
==========
e1 : GeometryEntity
e2 : GeometryEntity
Returns
=======
are_similar : boolean
Raises
======
GeometryError
When `e1` and `e2` cannot be compared.
Notes
=====
If the two objects are equal then they are similar.
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar
Examples
========
>>> from sympy import Point, Circle, Triangle, are_similar
>>> c1, c2 = Circle(Point(0, 0), 4), Circle(Point(1, 4), 3)
>>> t1 = Triangle(Point(0, 0), Point(1, 0), Point(0, 1))
>>> t2 = Triangle(Point(0, 0), Point(2, 0), Point(0, 2))
>>> t3 = Triangle(Point(0, 0), Point(3, 0), Point(0, 1))
>>> are_similar(t1, t2)
True
>>> are_similar(t1, t3)
False
"""
from .exceptions import GeometryError
if e1 == e2:
return True
try:
return e1.is_similar(e2)
except AttributeError:
try:
return e2.is_similar(e1)
except AttributeError:
n1 = e1.__class__.__name__
n2 = e2.__class__.__name__
raise GeometryError(
"Cannot test similarity between %s and %s" % (n1, n2))
def centroid(*args):
"""Find the centroid (center of mass) of the collection containing only Points,
Segments or Polygons. The centroid is the weighted average of the individual centroid
where the weights are the lengths (of segments) or areas (of polygons).
Overlapping regions will add to the weight of that region.
If there are no objects (or a mixture of objects) then None is returned.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment,
sympy.geometry.polygon.Polygon
Examples
========
>>> from sympy import Point, Segment, Polygon
>>> from sympy.geometry.util import centroid
>>> p = Polygon((0, 0), (10, 0), (10, 10))
>>> q = p.translate(0, 20)
>>> p.centroid, q.centroid
(Point2D(20/3, 10/3), Point2D(20/3, 70/3))
>>> centroid(p, q)
Point2D(20/3, 40/3)
>>> p, q = Segment((0, 0), (2, 0)), Segment((0, 0), (2, 2))
>>> centroid(p, q)
Point2D(1, -sqrt(2) + 2)
>>> centroid(Point(0, 0), Point(2, 0))
Point2D(1, 0)
Stacking 3 polygons on top of each other effectively triples the
weight of that polygon:
>>> p = Polygon((0, 0), (1, 0), (1, 1), (0, 1))
>>> q = Polygon((1, 0), (3, 0), (3, 1), (1, 1))
>>> centroid(p, q)
Point2D(3/2, 1/2)
>>> centroid(p, p, p, q) # centroid x-coord shifts left
Point2D(11/10, 1/2)
Stacking the squares vertically above and below p has the same
effect:
>>> centroid(p, p.translate(0, 1), p.translate(0, -1), q)
Point2D(11/10, 1/2)
"""
from sympy.geometry import Polygon, Segment, Point
if args:
if all(isinstance(g, Point) for g in args):
c = Point(0, 0)
for g in args:
c += g
den = len(args)
elif all(isinstance(g, Segment) for g in args):
c = Point(0, 0)
L = 0
for g in args:
l = g.length
c += g.midpoint*l
L += l
den = L
elif all(isinstance(g, Polygon) for g in args):
c = Point(0, 0)
A = 0
for g in args:
a = g.area
c += g.centroid*a
A += a
den = A
c /= den
return c.func(*[i.simplify() for i in c.args])
def closest_points(*args):
"""Return the subset of points from a set of points that were
the closest to each other in the 2D plane.
Parameters
==========
args : a collection of Points on 2D plane.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line. If there are no ties then a single
pair of Points will be in the set.
References
==========
[1] http://www.cs.mcgill.ca/~cs251/ClosestPair/ClosestPairPS.html
[2] Sweep line algorithm
https://en.wikipedia.org/wiki/Sweep_line_algorithm
Examples
========
>>> from sympy.geometry import closest_points, Point2D, Triangle
>>> Triangle(sss=(3, 4, 5)).args
(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> closest_points(*_)
{(Point2D(0, 0), Point2D(3, 0))}
"""
from collections import deque
from math import hypot, sqrt as _sqrt
from sympy.functions.elementary.miscellaneous import sqrt
p = [Point2D(i) for i in set(args)]
if len(p) < 2:
raise ValueError('At least 2 distinct points must be given.')
try:
p.sort(key=lambda x: x.args)
except TypeError:
raise ValueError("The points could not be sorted.")
if any(not i.is_Rational for j in p for i in j.args):
def hypot(x, y):
arg = x*x + y*y
if arg.is_Rational:
return _sqrt(arg)
return sqrt(arg)
rv = [(0, 1)]
best_dist = hypot(p[1].x - p[0].x, p[1].y - p[0].y)
i = 2
left = 0
box = deque([0, 1])
while i < len(p):
while left < i and p[i][0] - p[left][0] > best_dist:
box.popleft()
left += 1
for j in box:
d = hypot(p[i].x - p[j].x, p[i].y - p[j].y)
if d < best_dist:
rv = [(j, i)]
elif d == best_dist:
rv.append((j, i))
else:
continue
best_dist = d
box.append(i)
i += 1
return {tuple([p[i] for i in pair]) for pair in rv}
def convex_hull(*args, **kwargs):
"""The convex hull surrounding the Points contained in the list of entities.
Parameters
==========
args : a collection of Points, Segments and/or Polygons
Returns
=======
convex_hull : Polygon if ``polygon`` is True else as a tuple `(U, L)` where ``L`` and ``U`` are the lower and upper hulls, respectively.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line.
References
==========
[1] https://en.wikipedia.org/wiki/Graham_scan
[2] Andrew's Monotone Chain Algorithm
(A.M. Andrew,
"Another Efficient Algorithm for Convex Hulls in Two Dimensions", 1979)
http://geomalgorithms.com/a10-_hull-1.html
See Also
========
sympy.geometry.point.Point, sympy.geometry.polygon.Polygon
Examples
========
>>> from sympy.geometry import Point, convex_hull
>>> points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)]
>>> convex_hull(*points)
Polygon(Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4))
>>> convex_hull(*points, **dict(polygon=False))
([Point2D(-5, 2), Point2D(15, 4)],
[Point2D(-5, 2), Point2D(1, 1), Point2D(3, 1), Point2D(15, 4)])
"""
from .entity import GeometryEntity
from .point import Point
from .line import Segment
from .polygon import Polygon
polygon = kwargs.get('polygon', True)
p = OrderedSet()
for e in args:
if not isinstance(e, GeometryEntity):
try:
e = Point(e)
except NotImplementedError:
raise ValueError('%s is not a GeometryEntity and cannot be made into Point' % str(e))
if isinstance(e, Point):
p.add(e)
elif isinstance(e, Segment):
p.update(e.points)
elif isinstance(e, Polygon):
p.update(e.vertices)
else:
raise NotImplementedError(
'Convex hull for %s not implemented.' % type(e))
# make sure all our points are of the same dimension
if any(len(x) != 2 for x in p):
raise ValueError('Can only compute the convex hull in two dimensions')
p = list(p)
if len(p) == 1:
return p[0] if polygon else (p[0], None)
elif len(p) == 2:
s = Segment(p[0], p[1])
return s if polygon else (s, None)
def _orientation(p, q, r):
'''Return positive if p-q-r are clockwise, neg if ccw, zero if
collinear.'''
return (q.y - p.y)*(r.x - p.x) - (q.x - p.x)*(r.y - p.y)
# scan to find upper and lower convex hulls of a set of 2d points.
U = []
L = []
try:
p.sort(key=lambda x: x.args)
except TypeError:
raise ValueError("The points could not be sorted.")
for p_i in p:
while len(U) > 1 and _orientation(U[-2], U[-1], p_i) <= 0:
U.pop()
while len(L) > 1 and _orientation(L[-2], L[-1], p_i) >= 0:
L.pop()
U.append(p_i)
L.append(p_i)
U.reverse()
convexHull = tuple(L + U[1:-1])
if len(convexHull) == 2:
s = Segment(convexHull[0], convexHull[1])
return s if polygon else (s, None)
if polygon:
return Polygon(*convexHull)
else:
U.reverse()
return (U, L)
def farthest_points(*args):
"""Return the subset of points from a set of points that were
the furthest apart from each other in the 2D plane.
Parameters
==========
args : a collection of Points on 2D plane.
Notes
=====
This can only be performed on a set of points whose coordinates can
be ordered on the number line. If there are no ties then a single
pair of Points will be in the set.
References
==========
[1] http://code.activestate.com/recipes/117225-convex-hull-and-diameter-of-2d-point-sets/
[2] Rotating Callipers Technique
https://en.wikipedia.org/wiki/Rotating_calipers
Examples
========
>>> from sympy.geometry import farthest_points, Point2D, Triangle
>>> Triangle(sss=(3, 4, 5)).args
(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> farthest_points(*_)
{(Point2D(0, 0), Point2D(3, 4))}
"""
from math import hypot, sqrt as _sqrt
def rotatingCalipers(Points):
U, L = convex_hull(*Points, **dict(polygon=False))
if L is None:
if isinstance(U, Point):
raise ValueError('At least two distinct points must be given.')
yield U.args
else:
i = 0
j = len(L) - 1
while i < len(U) - 1 or j > 0:
yield U[i], L[j]
# if all the way through one side of hull, advance the other side
if i == len(U) - 1:
j -= 1
elif j == 0:
i += 1
# still points left on both lists, compare slopes of next hull edges
# being careful to avoid divide-by-zero in slope calculation
elif (U[i+1].y - U[i].y) * (L[j].x - L[j-1].x) > \
(L[j].y - L[j-1].y) * (U[i+1].x - U[i].x):
i += 1
else:
j -= 1
p = [Point2D(i) for i in set(args)]
if any(not i.is_Rational for j in p for i in j.args):
def hypot(x, y):
arg = x*x + y*y
if arg.is_Rational:
return _sqrt(arg)
return sqrt(arg)
rv = []
diam = 0
for pair in rotatingCalipers(args):
h, q = _ordered_points(pair)
d = hypot(h.x - q.x, h.y - q.y)
if d > diam:
rv = [(h, q)]
elif d == diam:
rv.append((h, q))
else:
continue
diam = d
return set(rv)
def idiff(eq, y, x, n=1):
"""Return ``dy/dx`` assuming that ``eq == 0``.
Parameters
==========
y : the dependent variable or a list of dependent variables (with y first)
x : the variable that the derivative is being taken with respect to
n : the order of the derivative (default is 1)
Examples
========
>>> from sympy.abc import x, y, a
>>> from sympy.geometry.util import idiff
>>> circ = x**2 + y**2 - 4
>>> idiff(circ, y, x)
-x/y
>>> idiff(circ, y, x, 2).simplify()
-(x**2 + y**2)/y**3
Here, ``a`` is assumed to be independent of ``x``:
>>> idiff(x + a + y, y, x)
-1
Now the x-dependence of ``a`` is made explicit by listing ``a`` after
``y`` in a list.
>>> idiff(x + a + y, [y, a], x)
-Derivative(a, x) - 1
See Also
========
sympy.core.function.Derivative: represents unevaluated derivatives
sympy.core.function.diff: explicitly differentiates wrt symbols
"""
if is_sequence(y):
dep = set(y)
y = y[0]
elif isinstance(y, Symbol):
dep = {y}
elif isinstance(y, Function):
pass
else:
raise ValueError("expecting x-dependent symbol(s) or function(s) but got: %s" % y)
f = dict([(s, Function(
s.name)(x)) for s in eq.free_symbols if s != x and s in dep])
if isinstance(y, Symbol):
dydx = Function(y.name)(x).diff(x)
else:
dydx = y.diff(x)
eq = eq.subs(f)
derivs = {}
for i in range(n):
yp = solve(eq.diff(x), dydx)[0].subs(derivs)
if i == n - 1:
return yp.subs([(v, k) for k, v in f.items()])
derivs[dydx] = yp
eq = dydx - yp
dydx = dydx.diff(x)
def intersection(*entities, **kwargs):
"""The intersection of a collection of GeometryEntity instances.
Parameters
==========
entities : sequence of GeometryEntity
pairwise (keyword argument) : Can be either True or False
Returns
=======
intersection : list of GeometryEntity
Raises
======
NotImplementedError
When unable to calculate intersection.
Notes
=====
The intersection of any geometrical entity with itself should return
a list with one item: the entity in question.
An intersection requires two or more entities. If only a single
entity is given then the function will return an empty list.
It is possible for `intersection` to miss intersections that one
knows exists because the required quantities were not fully
simplified internally.
Reals should be converted to Rationals, e.g. Rational(str(real_num))
or else failures due to floating point issues may result.
Case 1: When the keyword argument 'pairwise' is False (default value):
In this case, the function returns a list of intersections common to
all entities.
Case 2: When the keyword argument 'pairwise' is True:
In this case, the functions returns a list intersections that occur
between any pair of entities.
See Also
========
sympy.geometry.entity.GeometryEntity.intersection
Examples
========
>>> from sympy.geometry import Ray, Circle, intersection
>>> c = Circle((0, 1), 1)
>>> intersection(c, c.center)
[]
>>> right = Ray((0, 0), (1, 0))
>>> up = Ray((0, 0), (0, 1))
>>> intersection(c, right, up)
[Point2D(0, 0)]
>>> intersection(c, right, up, pairwise=True)
[Point2D(0, 0), Point2D(0, 2)]
>>> left = Ray((1, 0), (0, 0))
>>> intersection(right, left)
[Segment2D(Point2D(0, 0), Point2D(1, 0))]
"""
from .entity import GeometryEntity
from .point import Point
pairwise = kwargs.pop('pairwise', False)
if len(entities) <= 1:
return []
# entities may be an immutable tuple
entities = list(entities)
for i, e in enumerate(entities):
if not isinstance(e, GeometryEntity):
entities[i] = Point(e)
if not pairwise:
# find the intersection common to all objects
res = entities[0].intersection(entities[1])
for entity in entities[2:]:
newres = []
for x in res:
newres.extend(x.intersection(entity))
res = newres
return res
# find all pairwise intersections
ans = []
for j in range(0, len(entities)):
for k in range(j + 1, len(entities)):
ans.extend(intersection(entities[j], entities[k]))
return list(ordered(set(ans)))
|
490390e391475327ecf0f1eaabcc7af2a981cfea592dbb560767f20059ae7934
|
from __future__ import division, print_function
from sympy.core import Expr, S, Symbol, oo, pi, sympify
from sympy.core.compatibility import as_int, range, ordered
from sympy.core.symbol import _symbol, Dummy
from sympy.functions.elementary.complexes import sign
from sympy.functions.elementary.piecewise import Piecewise
from sympy.functions.elementary.trigonometric import cos, sin, tan
from sympy.geometry.exceptions import GeometryError
from sympy.logic import And
from sympy.matrices import Matrix
from sympy.simplify import simplify
from sympy.utilities import default_sort_key
from sympy.utilities.iterables import has_dups, has_variety, uniq, rotate_left, least_rotation
from sympy.utilities.misc import func_name
from .entity import GeometryEntity, GeometrySet
from .point import Point
from .ellipse import Circle
from .line import Line, Segment, Ray
from sympy import sqrt
import warnings
class Polygon(GeometrySet):
"""A two-dimensional polygon.
A simple polygon in space. Can be constructed from a sequence of points
or from a center, radius, number of sides and rotation angle.
Parameters
==========
vertices : sequence of Points
Attributes
==========
area
angles
perimeter
vertices
centroid
sides
Raises
======
GeometryError
If all parameters are not Points.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment, Triangle
Notes
=====
Polygons are treated as closed paths rather than 2D areas so
some calculations can be be negative or positive (e.g., area)
based on the orientation of the points.
Any consecutive identical points are reduced to a single point
and any points collinear and between two points will be removed
unless they are needed to define an explicit intersection (see examples).
A Triangle, Segment or Point will be returned when there are 3 or
fewer points provided.
Examples
========
>>> from sympy import Point, Polygon, pi
>>> p1, p2, p3, p4, p5 = [(0, 0), (1, 0), (5, 1), (0, 1), (3, 0)]
>>> Polygon(p1, p2, p3, p4)
Polygon(Point2D(0, 0), Point2D(1, 0), Point2D(5, 1), Point2D(0, 1))
>>> Polygon(p1, p2)
Segment2D(Point2D(0, 0), Point2D(1, 0))
>>> Polygon(p1, p2, p5)
Segment2D(Point2D(0, 0), Point2D(3, 0))
The area of a polygon is calculated as positive when vertices are
traversed in a ccw direction. When the sides of a polygon cross the
area will have positive and negative contributions. The following
defines a Z shape where the bottom right connects back to the top
left.
>>> Polygon((0, 2), (2, 2), (0, 0), (2, 0)).area
0
When the the keyword `n` is used to define the number of sides of the
Polygon then a RegularPolygon is created and the other arguments are
interpreted as center, radius and rotation. The unrotated RegularPolygon
will always have a vertex at Point(r, 0) where `r` is the radius of the
circle that circumscribes the RegularPolygon. Its method `spin` can be
used to increment that angle.
>>> p = Polygon((0,0), 1, n=3)
>>> p
RegularPolygon(Point2D(0, 0), 1, 3, 0)
>>> p.vertices[0]
Point2D(1, 0)
>>> p.args[0]
Point2D(0, 0)
>>> p.spin(pi/2)
>>> p.vertices[0]
Point2D(0, 1)
"""
def __new__(cls, *args, **kwargs):
if kwargs.get('n', 0):
n = kwargs.pop('n')
args = list(args)
# return a virtual polygon with n sides
if len(args) == 2: # center, radius
args.append(n)
elif len(args) == 3: # center, radius, rotation
args.insert(2, n)
return RegularPolygon(*args, **kwargs)
vertices = [Point(a, dim=2, **kwargs) for a in args]
# remove consecutive duplicates
nodup = []
for p in vertices:
if nodup and p == nodup[-1]:
continue
nodup.append(p)
if len(nodup) > 1 and nodup[-1] == nodup[0]:
nodup.pop() # last point was same as first
# remove collinear points
i = -3
while i < len(nodup) - 3 and len(nodup) > 2:
a, b, c = nodup[i], nodup[i + 1], nodup[i + 2]
if Point.is_collinear(a, b, c):
nodup.pop(i + 1)
if a == c:
nodup.pop(i)
else:
i += 1
vertices = list(nodup)
if len(vertices) > 3:
return GeometryEntity.__new__(cls, *vertices, **kwargs)
elif len(vertices) == 3:
return Triangle(*vertices, **kwargs)
elif len(vertices) == 2:
return Segment(*vertices, **kwargs)
else:
return Point(*vertices, **kwargs)
@property
def area(self):
"""
The area of the polygon.
Notes
=====
The area calculation can be positive or negative based on the
orientation of the points. If any side of the polygon crosses
any other side, there will be areas having opposite signs.
See Also
========
sympy.geometry.ellipse.Ellipse.area
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.area
3
In the Z shaped polygon (with the lower right connecting back
to the upper left) the areas cancel out:
>>> Z = Polygon((0, 1), (1, 1), (0, 0), (1, 0))
>>> Z.area
0
In the M shaped polygon, areas do not cancel because no side
crosses any other (though there is a point of contact).
>>> M = Polygon((0, 0), (0, 1), (2, 0), (3, 1), (3, 0))
>>> M.area
-3/2
"""
area = 0
args = self.args
for i in range(len(args)):
x1, y1 = args[i - 1].args
x2, y2 = args[i].args
area += x1*y2 - x2*y1
return simplify(area) / 2
@staticmethod
def _isright(a, b, c):
"""Return True/False for cw/ccw orientation.
Examples
========
>>> from sympy import Point, Polygon
>>> a, b, c = [Point(i) for i in [(0, 0), (1, 1), (1, 0)]]
>>> Polygon._isright(a, b, c)
True
>>> Polygon._isright(a, c, b)
False
"""
ba = b - a
ca = c - a
t_area = simplify(ba.x*ca.y - ca.x*ba.y)
res = t_area.is_nonpositive
if res is None:
raise ValueError("Can't determine orientation")
return res
@property
def angles(self):
"""The internal angle at each vertex.
Returns
=======
angles : dict
A dictionary where each key is a vertex and each value is the
internal angle at that vertex. The vertices are represented as
Points.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.angles[p1]
pi/2
>>> poly.angles[p2]
acos(-4*sqrt(17)/17)
"""
# Determine orientation of points
args = self.vertices
cw = self._isright(args[-1], args[0], args[1])
ret = {}
for i in range(len(args)):
a, b, c = args[i - 2], args[i - 1], args[i]
ang = Ray(b, a).angle_between(Ray(b, c))
if cw ^ self._isright(a, b, c):
ret[b] = 2*S.Pi - ang
else:
ret[b] = ang
return ret
@property
def ambient_dimension(self):
return self.vertices[0].ambient_dimension
@property
def perimeter(self):
"""The perimeter of the polygon.
Returns
=======
perimeter : number or Basic instance
See Also
========
sympy.geometry.line.Segment.length
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.perimeter
sqrt(17) + 7
"""
p = 0
args = self.vertices
for i in range(len(args)):
p += args[i - 1].distance(args[i])
return simplify(p)
@property
def vertices(self):
"""The vertices of the polygon.
Returns
=======
vertices : list of Points
Notes
=====
When iterating over the vertices, it is more efficient to index self
rather than to request the vertices and index them. Only use the
vertices when you want to process all of them at once. This is even
more important with RegularPolygons that calculate each vertex.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.vertices
[Point2D(0, 0), Point2D(1, 0), Point2D(5, 1), Point2D(0, 1)]
>>> poly.vertices[0]
Point2D(0, 0)
"""
return list(self.args)
@property
def centroid(self):
"""The centroid of the polygon.
Returns
=======
centroid : Point
See Also
========
sympy.geometry.point.Point, sympy.geometry.util.centroid
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.centroid
Point2D(31/18, 11/18)
"""
A = 1/(6*self.area)
cx, cy = 0, 0
args = self.args
for i in range(len(args)):
x1, y1 = args[i - 1].args
x2, y2 = args[i].args
v = x1*y2 - x2*y1
cx += v*(x1 + x2)
cy += v*(y1 + y2)
return Point(simplify(A*cx), simplify(A*cy))
def second_moment_of_area(self, point=None):
"""Returns the second moment and product moment of area of a two dimensional polygon.
Parameters
==========
point : Point, two-tuple of sympifiable objects, or None(default=None)
point is the point about which second moment of area is to be found.
If "point=None" it will be calculated about the axis passing through the
centroid of the polygon.
Returns
=======
I_xx, I_yy, I_xy : number or sympy expression
I_xx, I_yy are second moment of area of a two dimensional polygon.
I_xy is product moment of area of a two dimensional polygon.
Examples
========
>>> from sympy import Point, Polygon, symbols
>>> a, b = symbols('a, b')
>>> p1, p2, p3, p4, p5 = [(0, 0), (a, 0), (a, b), (0, b), (a/3, b/3)]
>>> rectangle = Polygon(p1, p2, p3, p4)
>>> rectangle.second_moment_of_area()
(a*b**3/12, a**3*b/12, 0)
>>> rectangle.second_moment_of_area(p5)
(a*b**3/9, a**3*b/9, a**2*b**2/36)
References
==========
https://en.wikipedia.org/wiki/Second_moment_of_area
"""
I_xx, I_yy, I_xy = 0, 0, 0
args = self.args
for i in range(len(args)):
x1, y1 = args[i-1].args
x2, y2 = args[i].args
v = x1*y2 - x2*y1
I_xx += (y1**2 + y1*y2 + y2**2)*v
I_yy += (x1**2 + x1*x2 + x2**2)*v
I_xy += (x1*y2 + 2*x1*y1 + 2*x2*y2 + x2*y1)*v
A = self.area
c_x = self.centroid[0]
c_y = self.centroid[1]
# parallel axis theorem
I_xx_c = (I_xx/12) - (A*(c_y**2))
I_yy_c = (I_yy/12) - (A*(c_x**2))
I_xy_c = (I_xy/24) - (A*(c_x*c_y))
if point is None:
return I_xx_c, I_yy_c, I_xy_c
I_xx = (I_xx_c + A*((point[1]-c_y)**2))
I_yy = (I_yy_c + A*((point[0]-c_x)**2))
I_xy = (I_xy_c + A*((point[0]-c_x)*(point[1]-c_y)))
return I_xx, I_yy, I_xy
@property
def sides(self):
"""The directed line segments that form the sides of the polygon.
Returns
=======
sides : list of sides
Each side is a directed Segment.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.sides
[Segment2D(Point2D(0, 0), Point2D(1, 0)),
Segment2D(Point2D(1, 0), Point2D(5, 1)),
Segment2D(Point2D(5, 1), Point2D(0, 1)), Segment2D(Point2D(0, 1), Point2D(0, 0))]
"""
res = []
args = self.vertices
for i in range(-len(args), 0):
res.append(Segment(args[i], args[i + 1]))
return res
@property
def bounds(self):
"""Return a tuple (xmin, ymin, xmax, ymax) representing the bounding
rectangle for the geometric figure.
"""
verts = self.vertices
xs = [p.x for p in verts]
ys = [p.y for p in verts]
return (min(xs), min(ys), max(xs), max(ys))
def is_convex(self):
"""Is the polygon convex?
A polygon is convex if all its interior angles are less than 180
degrees and there are no intersections between sides.
Returns
=======
is_convex : boolean
True if this polygon is convex, False otherwise.
See Also
========
sympy.geometry.util.convex_hull
Examples
========
>>> from sympy import Point, Polygon
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly = Polygon(p1, p2, p3, p4)
>>> poly.is_convex()
True
"""
# Determine orientation of points
args = self.vertices
cw = self._isright(args[-2], args[-1], args[0])
for i in range(1, len(args)):
if cw ^ self._isright(args[i - 2], args[i - 1], args[i]):
return False
# check for intersecting sides
sides = self.sides
for i, si in enumerate(sides):
pts = si.args
# exclude the sides connected to si
for j in range(1 if i == len(sides) - 1 else 0, i - 1):
sj = sides[j]
if sj.p1 not in pts and sj.p2 not in pts:
hit = si.intersection(sj)
if hit:
return False
return True
def encloses_point(self, p):
"""
Return True if p is enclosed by (is inside of) self.
Notes
=====
Being on the border of self is considered False.
Parameters
==========
p : Point
Returns
=======
encloses_point : True, False or None
See Also
========
sympy.geometry.point.Point, sympy.geometry.ellipse.Ellipse.encloses_point
Examples
========
>>> from sympy import Polygon, Point
>>> from sympy.abc import t
>>> p = Polygon((0, 0), (4, 0), (4, 4))
>>> p.encloses_point(Point(2, 1))
True
>>> p.encloses_point(Point(2, 2))
False
>>> p.encloses_point(Point(5, 5))
False
References
==========
[1] http://paulbourke.net/geometry/polygonmesh/#insidepoly
"""
p = Point(p, dim=2)
if p in self.vertices or any(p in s for s in self.sides):
return False
# move to p, checking that the result is numeric
lit = []
for v in self.vertices:
lit.append(v - p) # the difference is simplified
if lit[-1].free_symbols:
return None
poly = Polygon(*lit)
# polygon closure is assumed in the following test but Polygon removes duplicate pts so
# the last point has to be added so all sides are computed. Using Polygon.sides is
# not good since Segments are unordered.
args = poly.args
indices = list(range(-len(args), 1))
if poly.is_convex():
orientation = None
for i in indices:
a = args[i]
b = args[i + 1]
test = ((-a.y)*(b.x - a.x) - (-a.x)*(b.y - a.y)).is_negative
if orientation is None:
orientation = test
elif test is not orientation:
return False
return True
hit_odd = False
p1x, p1y = args[0].args
for i in indices[1:]:
p2x, p2y = args[i].args
if 0 > min(p1y, p2y):
if 0 <= max(p1y, p2y):
if 0 <= max(p1x, p2x):
if p1y != p2y:
xinters = (-p1y)*(p2x - p1x)/(p2y - p1y) + p1x
if p1x == p2x or 0 <= xinters:
hit_odd = not hit_odd
p1x, p1y = p2x, p2y
return hit_odd
def arbitrary_point(self, parameter='t'):
"""A parameterized point on the polygon.
The parameter, varying from 0 to 1, assigns points to the position on
the perimeter that is that fraction of the total perimeter. So the
point evaluated at t=1/2 would return the point from the first vertex
that is 1/2 way around the polygon.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
arbitrary_point : Point
Raises
======
ValueError
When `parameter` already appears in the Polygon's definition.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy import Polygon, S, Symbol
>>> t = Symbol('t', real=True)
>>> tri = Polygon((0, 0), (1, 0), (1, 1))
>>> p = tri.arbitrary_point('t')
>>> perimeter = tri.perimeter
>>> s1, s2 = [s.length for s in tri.sides[:2]]
>>> p.subs(t, (s1 + s2/2)/perimeter)
Point2D(1, 1/2)
"""
t = _symbol(parameter, real=True)
if t.name in (f.name for f in self.free_symbols):
raise ValueError('Symbol %s already appears in object and cannot be used as a parameter.' % t.name)
sides = []
perimeter = self.perimeter
perim_fraction_start = 0
for s in self.sides:
side_perim_fraction = s.length/perimeter
perim_fraction_end = perim_fraction_start + side_perim_fraction
pt = s.arbitrary_point(parameter).subs(
t, (t - perim_fraction_start)/side_perim_fraction)
sides.append(
(pt, (And(perim_fraction_start <= t, t < perim_fraction_end))))
perim_fraction_start = perim_fraction_end
return Piecewise(*sides)
def parameter_value(self, other, t):
from sympy.solvers.solvers import solve
if not isinstance(other,GeometryEntity):
other = Point(other, dim=self.ambient_dimension)
if not isinstance(other,Point):
raise ValueError("other must be a point")
if other.free_symbols:
raise NotImplementedError('non-numeric coordinates')
unknown = False
T = Dummy('t', real=True)
p = self.arbitrary_point(T)
for pt, cond in p.args:
sol = solve(pt - other, T, dict=True)
if not sol:
continue
value = sol[0][T]
if simplify(cond.subs(T, value)) == True:
return {t: value}
unknown = True
if unknown:
raise ValueError("Given point may not be on %s" % func_name(self))
raise ValueError("Given point is not on %s" % func_name(self))
def plot_interval(self, parameter='t'):
"""The plot interval for the default geometric plot of the polygon.
Parameters
==========
parameter : str, optional
Default value is 't'.
Returns
=======
plot_interval : list (plot interval)
[parameter, lower_bound, upper_bound]
Examples
========
>>> from sympy import Polygon
>>> p = Polygon((0, 0), (1, 0), (1, 1))
>>> p.plot_interval()
[t, 0, 1]
"""
t = Symbol(parameter, real=True)
return [t, 0, 1]
def intersection(self, o):
"""The intersection of polygon and geometry entity.
The intersection may be empty and can contain individual Points and
complete Line Segments.
Parameters
==========
other: GeometryEntity
Returns
=======
intersection : list
The list of Segments and Points
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy import Point, Polygon, Line
>>> p1, p2, p3, p4 = map(Point, [(0, 0), (1, 0), (5, 1), (0, 1)])
>>> poly1 = Polygon(p1, p2, p3, p4)
>>> p5, p6, p7 = map(Point, [(3, 2), (1, -1), (0, 2)])
>>> poly2 = Polygon(p5, p6, p7)
>>> poly1.intersection(poly2)
[Point2D(1/3, 1), Point2D(2/3, 0), Point2D(9/5, 1/5), Point2D(7/3, 1)]
>>> poly1.intersection(Line(p1, p2))
[Segment2D(Point2D(0, 0), Point2D(1, 0))]
>>> poly1.intersection(p1)
[Point2D(0, 0)]
"""
intersection_result = []
k = o.sides if isinstance(o, Polygon) else [o]
for side in self.sides:
for side1 in k:
intersection_result.extend(side.intersection(side1))
intersection_result = list(uniq(intersection_result))
points = [entity for entity in intersection_result if isinstance(entity, Point)]
segments = [entity for entity in intersection_result if isinstance(entity, Segment)]
if points and segments:
points_in_segments = list(uniq([point for point in points for segment in segments if point in segment]))
if points_in_segments:
for i in points_in_segments:
points.remove(i)
return list(ordered(segments + points))
else:
return list(ordered(intersection_result))
def distance(self, o):
"""
Returns the shortest distance between self and o.
If o is a point, then self does not need to be convex.
If o is another polygon self and o must be complex.
Examples
========
>>> from sympy import Point, Polygon, RegularPolygon
>>> p1, p2 = map(Point, [(0, 0), (7, 5)])
>>> poly = Polygon(*RegularPolygon(p1, 1, 3).vertices)
>>> poly.distance(p2)
sqrt(61)
"""
if isinstance(o, Point):
dist = oo
for side in self.sides:
current = side.distance(o)
if current == 0:
return S.Zero
elif current < dist:
dist = current
return dist
elif isinstance(o, Polygon) and self.is_convex() and o.is_convex():
return self._do_poly_distance(o)
raise NotImplementedError()
def _do_poly_distance(self, e2):
"""
Calculates the least distance between the exteriors of two
convex polygons e1 and e2. Does not check for the convexity
of the polygons as this is checked by Polygon.distance.
Notes
=====
- Prints a warning if the two polygons possibly intersect as the return
value will not be valid in such a case. For a more through test of
intersection use intersection().
See Also
========
sympy.geometry.point.Point.distance
Examples
========
>>> from sympy.geometry import Point, Polygon
>>> square = Polygon(Point(0, 0), Point(0, 1), Point(1, 1), Point(1, 0))
>>> triangle = Polygon(Point(1, 2), Point(2, 2), Point(2, 1))
>>> square._do_poly_distance(triangle)
sqrt(2)/2
Description of method used
==========================
Method:
[1] http://cgm.cs.mcgill.ca/~orm/mind2p.html
Uses rotating calipers:
[2] https://en.wikipedia.org/wiki/Rotating_calipers
and antipodal points:
[3] https://en.wikipedia.org/wiki/Antipodal_point
"""
e1 = self
'''Tests for a possible intersection between the polygons and outputs a warning'''
e1_center = e1.centroid
e2_center = e2.centroid
e1_max_radius = S.Zero
e2_max_radius = S.Zero
for vertex in e1.vertices:
r = Point.distance(e1_center, vertex)
if e1_max_radius < r:
e1_max_radius = r
for vertex in e2.vertices:
r = Point.distance(e2_center, vertex)
if e2_max_radius < r:
e2_max_radius = r
center_dist = Point.distance(e1_center, e2_center)
if center_dist <= e1_max_radius + e2_max_radius:
warnings.warn("Polygons may intersect producing erroneous output")
'''
Find the upper rightmost vertex of e1 and the lowest leftmost vertex of e2
'''
e1_ymax = Point(0, -oo)
e2_ymin = Point(0, oo)
for vertex in e1.vertices:
if vertex.y > e1_ymax.y or (vertex.y == e1_ymax.y and vertex.x > e1_ymax.x):
e1_ymax = vertex
for vertex in e2.vertices:
if vertex.y < e2_ymin.y or (vertex.y == e2_ymin.y and vertex.x < e2_ymin.x):
e2_ymin = vertex
min_dist = Point.distance(e1_ymax, e2_ymin)
'''
Produce a dictionary with vertices of e1 as the keys and, for each vertex, the points
to which the vertex is connected as its value. The same is then done for e2.
'''
e1_connections = {}
e2_connections = {}
for side in e1.sides:
if side.p1 in e1_connections:
e1_connections[side.p1].append(side.p2)
else:
e1_connections[side.p1] = [side.p2]
if side.p2 in e1_connections:
e1_connections[side.p2].append(side.p1)
else:
e1_connections[side.p2] = [side.p1]
for side in e2.sides:
if side.p1 in e2_connections:
e2_connections[side.p1].append(side.p2)
else:
e2_connections[side.p1] = [side.p2]
if side.p2 in e2_connections:
e2_connections[side.p2].append(side.p1)
else:
e2_connections[side.p2] = [side.p1]
e1_current = e1_ymax
e2_current = e2_ymin
support_line = Line(Point(S.Zero, S.Zero), Point(S.One, S.Zero))
'''
Determine which point in e1 and e2 will be selected after e2_ymin and e1_ymax,
this information combined with the above produced dictionaries determines the
path that will be taken around the polygons
'''
point1 = e1_connections[e1_ymax][0]
point2 = e1_connections[e1_ymax][1]
angle1 = support_line.angle_between(Line(e1_ymax, point1))
angle2 = support_line.angle_between(Line(e1_ymax, point2))
if angle1 < angle2:
e1_next = point1
elif angle2 < angle1:
e1_next = point2
elif Point.distance(e1_ymax, point1) > Point.distance(e1_ymax, point2):
e1_next = point2
else:
e1_next = point1
point1 = e2_connections[e2_ymin][0]
point2 = e2_connections[e2_ymin][1]
angle1 = support_line.angle_between(Line(e2_ymin, point1))
angle2 = support_line.angle_between(Line(e2_ymin, point2))
if angle1 > angle2:
e2_next = point1
elif angle2 > angle1:
e2_next = point2
elif Point.distance(e2_ymin, point1) > Point.distance(e2_ymin, point2):
e2_next = point2
else:
e2_next = point1
'''
Loop which determines the distance between anti-podal pairs and updates the
minimum distance accordingly. It repeats until it reaches the starting position.
'''
while True:
e1_angle = support_line.angle_between(Line(e1_current, e1_next))
e2_angle = pi - support_line.angle_between(Line(
e2_current, e2_next))
if (e1_angle < e2_angle) is True:
support_line = Line(e1_current, e1_next)
e1_segment = Segment(e1_current, e1_next)
min_dist_current = e1_segment.distance(e2_current)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e1_connections[e1_next][0] != e1_current:
e1_current = e1_next
e1_next = e1_connections[e1_next][0]
else:
e1_current = e1_next
e1_next = e1_connections[e1_next][1]
elif (e1_angle > e2_angle) is True:
support_line = Line(e2_next, e2_current)
e2_segment = Segment(e2_current, e2_next)
min_dist_current = e2_segment.distance(e1_current)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e2_connections[e2_next][0] != e2_current:
e2_current = e2_next
e2_next = e2_connections[e2_next][0]
else:
e2_current = e2_next
e2_next = e2_connections[e2_next][1]
else:
support_line = Line(e1_current, e1_next)
e1_segment = Segment(e1_current, e1_next)
e2_segment = Segment(e2_current, e2_next)
min1 = e1_segment.distance(e2_next)
min2 = e2_segment.distance(e1_next)
min_dist_current = min(min1, min2)
if min_dist_current.evalf() < min_dist.evalf():
min_dist = min_dist_current
if e1_connections[e1_next][0] != e1_current:
e1_current = e1_next
e1_next = e1_connections[e1_next][0]
else:
e1_current = e1_next
e1_next = e1_connections[e1_next][1]
if e2_connections[e2_next][0] != e2_current:
e2_current = e2_next
e2_next = e2_connections[e2_next][0]
else:
e2_current = e2_next
e2_next = e2_connections[e2_next][1]
if e1_current == e1_ymax and e2_current == e2_ymin:
break
return min_dist
def _svg(self, scale_factor=1., fill_color="#66cc99"):
"""Returns SVG path element for the Polygon.
Parameters
==========
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
fill_color : str, optional
Hex string for fill color. Default is "#66cc99".
"""
from sympy.core.evalf import N
verts = map(N, self.vertices)
coords = ["{0},{1}".format(p.x, p.y) for p in verts]
path = "M {0} L {1} z".format(coords[0], " L ".join(coords[1:]))
return (
'<path fill-rule="evenodd" fill="{2}" stroke="#555555" '
'stroke-width="{0}" opacity="0.6" d="{1}" />'
).format(2. * scale_factor, path, fill_color)
def _hashable_content(self):
D = {}
def ref_list(point_list):
kee = {}
for i, p in enumerate(ordered(set(point_list))):
kee[p] = i
D[i] = p
return [kee[p] for p in point_list]
S1 = ref_list(self.args)
r_nor = rotate_left(S1, least_rotation(S1))
S2 = ref_list(list(reversed(self.args)))
r_rev = rotate_left(S2, least_rotation(S2))
if r_nor < r_rev:
r = r_nor
else:
r = r_rev
canonical_args = [ D[order] for order in r ]
return tuple(canonical_args)
def __contains__(self, o):
"""
Return True if o is contained within the boundary lines of self.altitudes
Parameters
==========
other : GeometryEntity
Returns
=======
contained in : bool
The points (and sides, if applicable) are contained in self.
See Also
========
sympy.geometry.entity.GeometryEntity.encloses
Examples
========
>>> from sympy import Line, Segment, Point
>>> p = Point(0, 0)
>>> q = Point(1, 1)
>>> s = Segment(p, q*2)
>>> l = Line(p, q)
>>> p in q
False
>>> p in s
True
>>> q*3 in s
False
>>> s in l
True
"""
if isinstance(o, Polygon):
return self == o
elif isinstance(o, Segment):
return any(o in s for s in self.sides)
elif isinstance(o, Point):
if o in self.vertices:
return True
for side in self.sides:
if o in side:
return True
return False
class RegularPolygon(Polygon):
"""
A regular polygon.
Such a polygon has all internal angles equal and all sides the same length.
Parameters
==========
center : Point
radius : number or Basic instance
The distance from the center to a vertex
n : int
The number of sides
Attributes
==========
vertices
center
radius
rotation
apothem
interior_angle
exterior_angle
circumcircle
incircle
angles
Raises
======
GeometryError
If the `center` is not a Point, or the `radius` is not a number or Basic
instance, or the number of sides, `n`, is less than three.
Notes
=====
A RegularPolygon can be instantiated with Polygon with the kwarg n.
Regular polygons are instantiated with a center, radius, number of sides
and a rotation angle. Whereas the arguments of a Polygon are vertices, the
vertices of the RegularPolygon must be obtained with the vertices method.
See Also
========
sympy.geometry.point.Point, Polygon
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r
RegularPolygon(Point2D(0, 0), 5, 3, 0)
>>> r.vertices[0]
Point2D(5, 0)
"""
__slots__ = ['_n', '_center', '_radius', '_rot']
def __new__(self, c, r, n, rot=0, **kwargs):
r, n, rot = map(sympify, (r, n, rot))
c = Point(c, dim=2, **kwargs)
if not isinstance(r, Expr):
raise GeometryError("r must be an Expr object, not %s" % r)
if n.is_Number:
as_int(n) # let an error raise if necessary
if n < 3:
raise GeometryError("n must be a >= 3, not %s" % n)
obj = GeometryEntity.__new__(self, c, r, n, **kwargs)
obj._n = n
obj._center = c
obj._radius = r
obj._rot = rot % (2*S.Pi/n) if rot.is_number else rot
return obj
@property
def args(self):
"""
Returns the center point, the radius,
the number of sides, and the orientation angle.
Examples
========
>>> from sympy import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r.args
(Point2D(0, 0), 5, 3, 0)
"""
return self._center, self._radius, self._n, self._rot
def __str__(self):
return 'RegularPolygon(%s, %s, %s, %s)' % tuple(self.args)
def __repr__(self):
return 'RegularPolygon(%s, %s, %s, %s)' % tuple(self.args)
@property
def area(self):
"""Returns the area.
Examples
========
>>> from sympy.geometry import RegularPolygon
>>> square = RegularPolygon((0, 0), 1, 4)
>>> square.area
2
>>> _ == square.length**2
True
"""
c, r, n, rot = self.args
return sign(r)*n*self.length**2/(4*tan(pi/n))
@property
def length(self):
"""Returns the length of the sides.
The half-length of the side and the apothem form two legs
of a right triangle whose hypotenuse is the radius of the
regular polygon.
Examples
========
>>> from sympy.geometry import RegularPolygon
>>> from sympy import sqrt
>>> s = square_in_unit_circle = RegularPolygon((0, 0), 1, 4)
>>> s.length
sqrt(2)
>>> sqrt((_/2)**2 + s.apothem**2) == s.radius
True
"""
return self.radius*2*sin(pi/self._n)
@property
def center(self):
"""The center of the RegularPolygon
This is also the center of the circumscribing circle.
Returns
=======
center : Point
See Also
========
sympy.geometry.point.Point, sympy.geometry.ellipse.Ellipse.center
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.center
Point2D(0, 0)
"""
return self._center
centroid = center
@property
def circumcenter(self):
"""
Alias for center.
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.circumcenter
Point2D(0, 0)
"""
return self.center
@property
def radius(self):
"""Radius of the RegularPolygon
This is also the radius of the circumscribing circle.
Returns
=======
radius : number or instance of Basic
See Also
========
sympy.geometry.line.Segment.length, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy.geometry import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.radius
r
"""
return self._radius
@property
def circumradius(self):
"""
Alias for radius.
Examples
========
>>> from sympy import Symbol
>>> from sympy.geometry import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.circumradius
r
"""
return self.radius
@property
def rotation(self):
"""CCW angle by which the RegularPolygon is rotated
Returns
=======
rotation : number or instance of Basic
Examples
========
>>> from sympy import pi
>>> from sympy.abc import a
>>> from sympy.geometry import RegularPolygon, Point
>>> RegularPolygon(Point(0, 0), 3, 4, pi/4).rotation
pi/4
Numerical rotation angles are made canonical:
>>> RegularPolygon(Point(0, 0), 3, 4, a).rotation
a
>>> RegularPolygon(Point(0, 0), 3, 4, pi).rotation
0
"""
return self._rot
@property
def apothem(self):
"""The inradius of the RegularPolygon.
The apothem/inradius is the radius of the inscribed circle.
Returns
=======
apothem : number or instance of Basic
See Also
========
sympy.geometry.line.Segment.length, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy.geometry import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.apothem
sqrt(2)*r/2
"""
return self.radius * cos(S.Pi/self._n)
@property
def inradius(self):
"""
Alias for apothem.
Examples
========
>>> from sympy import Symbol
>>> from sympy.geometry import RegularPolygon, Point
>>> radius = Symbol('r')
>>> rp = RegularPolygon(Point(0, 0), radius, 4)
>>> rp.inradius
sqrt(2)*r/2
"""
return self.apothem
@property
def interior_angle(self):
"""Measure of the interior angles.
Returns
=======
interior_angle : number
See Also
========
sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.interior_angle
3*pi/4
"""
return (self._n - 2)*S.Pi/self._n
@property
def exterior_angle(self):
"""Measure of the exterior angles.
Returns
=======
exterior_angle : number
See Also
========
sympy.geometry.line.LinearEntity.angle_between
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.exterior_angle
pi/4
"""
return 2*S.Pi/self._n
@property
def circumcircle(self):
"""The circumcircle of the RegularPolygon.
Returns
=======
circumcircle : Circle
See Also
========
circumcenter, sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 8)
>>> rp.circumcircle
Circle(Point2D(0, 0), 4)
"""
return Circle(self.center, self.radius)
@property
def incircle(self):
"""The incircle of the RegularPolygon.
Returns
=======
incircle : Circle
See Also
========
inradius, sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 4, 7)
>>> rp.incircle
Circle(Point2D(0, 0), 4*cos(pi/7))
"""
return Circle(self.center, self.apothem)
@property
def angles(self):
"""
Returns a dictionary with keys, the vertices of the Polygon,
and values, the interior angle at each vertex.
Examples
========
>>> from sympy import RegularPolygon, Point
>>> r = RegularPolygon(Point(0, 0), 5, 3)
>>> r.angles
{Point2D(-5/2, -5*sqrt(3)/2): pi/3,
Point2D(-5/2, 5*sqrt(3)/2): pi/3,
Point2D(5, 0): pi/3}
"""
ret = {}
ang = self.interior_angle
for v in self.vertices:
ret[v] = ang
return ret
def encloses_point(self, p):
"""
Return True if p is enclosed by (is inside of) self.
Notes
=====
Being on the border of self is considered False.
The general Polygon.encloses_point method is called only if
a point is not within or beyond the incircle or circumcircle,
respectively.
Parameters
==========
p : Point
Returns
=======
encloses_point : True, False or None
See Also
========
sympy.geometry.ellipse.Ellipse.encloses_point
Examples
========
>>> from sympy import RegularPolygon, S, Point, Symbol
>>> p = RegularPolygon((0, 0), 3, 4)
>>> p.encloses_point(Point(0, 0))
True
>>> r, R = p.inradius, p.circumradius
>>> p.encloses_point(Point((r + R)/2, 0))
True
>>> p.encloses_point(Point(R/2, R/2 + (R - r)/10))
False
>>> t = Symbol('t', real=True)
>>> p.encloses_point(p.arbitrary_point().subs(t, S.Half))
False
>>> p.encloses_point(Point(5, 5))
False
"""
c = self.center
d = Segment(c, p).length
if d >= self.radius:
return False
elif d < self.inradius:
return True
else:
# now enumerate the RegularPolygon like a general polygon.
return Polygon.encloses_point(self, p)
def spin(self, angle):
"""Increment *in place* the virtual Polygon's rotation by ccw angle.
See also: rotate method which moves the center.
>>> from sympy import Polygon, Point, pi
>>> r = Polygon(Point(0,0), 1, n=3)
>>> r.vertices[0]
Point2D(1, 0)
>>> r.spin(pi/6)
>>> r.vertices[0]
Point2D(sqrt(3)/2, 1/2)
See Also
========
rotation
rotate : Creates a copy of the RegularPolygon rotated about a Point
"""
self._rot += angle
def rotate(self, angle, pt=None):
"""Override GeometryEntity.rotate to first rotate the RegularPolygon
about its center.
>>> from sympy import Point, RegularPolygon, Polygon, pi
>>> t = RegularPolygon(Point(1, 0), 1, 3)
>>> t.vertices[0] # vertex on x-axis
Point2D(2, 0)
>>> t.rotate(pi/2).vertices[0] # vertex on y axis now
Point2D(0, 2)
See Also
========
rotation
spin : Rotates a RegularPolygon in place
"""
r = type(self)(*self.args) # need a copy or else changes are in-place
r._rot += angle
return GeometryEntity.rotate(r, angle, pt)
def scale(self, x=1, y=1, pt=None):
"""Override GeometryEntity.scale since it is the radius that must be
scaled (if x == y) or else a new Polygon must be returned.
>>> from sympy import RegularPolygon
Symmetric scaling returns a RegularPolygon:
>>> RegularPolygon((0, 0), 1, 4).scale(2, 2)
RegularPolygon(Point2D(0, 0), 2, 4, 0)
Asymmetric scaling returns a kite as a Polygon:
>>> RegularPolygon((0, 0), 1, 4).scale(2, 1)
Polygon(Point2D(2, 0), Point2D(0, 1), Point2D(-2, 0), Point2D(0, -1))
"""
if pt:
pt = Point(pt, dim=2)
return self.translate(*(-pt).args).scale(x, y).translate(*pt.args)
if x != y:
return Polygon(*self.vertices).scale(x, y)
c, r, n, rot = self.args
r *= x
return self.func(c, r, n, rot)
def reflect(self, line):
"""Override GeometryEntity.reflect since this is not made of only
points.
Examples
========
>>> from sympy import RegularPolygon, Line
>>> RegularPolygon((0, 0), 1, 4).reflect(Line((0, 1), slope=-2))
RegularPolygon(Point2D(4/5, 2/5), -1, 4, atan(4/3))
"""
c, r, n, rot = self.args
v = self.vertices[0]
d = v - c
cc = c.reflect(line)
vv = v.reflect(line)
dd = vv - cc
# calculate rotation about the new center
# which will align the vertices
l1 = Ray((0, 0), dd)
l2 = Ray((0, 0), d)
ang = l1.closing_angle(l2)
rot += ang
# change sign of radius as point traversal is reversed
return self.func(cc, -r, n, rot)
@property
def vertices(self):
"""The vertices of the RegularPolygon.
Returns
=======
vertices : list
Each vertex is a Point.
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy.geometry import RegularPolygon, Point
>>> rp = RegularPolygon(Point(0, 0), 5, 4)
>>> rp.vertices
[Point2D(5, 0), Point2D(0, 5), Point2D(-5, 0), Point2D(0, -5)]
"""
c = self._center
r = abs(self._radius)
rot = self._rot
v = 2*S.Pi/self._n
return [Point(c.x + r*cos(k*v + rot), c.y + r*sin(k*v + rot))
for k in range(self._n)]
def __eq__(self, o):
if not isinstance(o, Polygon):
return False
elif not isinstance(o, RegularPolygon):
return Polygon.__eq__(o, self)
return self.args == o.args
def __hash__(self):
return super(RegularPolygon, self).__hash__()
class Triangle(Polygon):
"""
A polygon with three vertices and three sides.
Parameters
==========
points : sequence of Points
keyword: asa, sas, or sss to specify sides/angles of the triangle
Attributes
==========
vertices
altitudes
orthocenter
circumcenter
circumradius
circumcircle
inradius
incircle
exradii
medians
medial
nine_point_circle
Raises
======
GeometryError
If the number of vertices is not equal to three, or one of the vertices
is not a Point, or a valid keyword is not given.
See Also
========
sympy.geometry.point.Point, Polygon
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
Triangle(Point2D(0, 0), Point2D(4, 0), Point2D(4, 3))
Keywords sss, sas, or asa can be used to give the desired
side lengths (in order) and interior angles (in degrees) that
define the triangle:
>>> Triangle(sss=(3, 4, 5))
Triangle(Point2D(0, 0), Point2D(3, 0), Point2D(3, 4))
>>> Triangle(asa=(30, 1, 30))
Triangle(Point2D(0, 0), Point2D(1, 0), Point2D(1/2, sqrt(3)/6))
>>> Triangle(sas=(1, 45, 2))
Triangle(Point2D(0, 0), Point2D(2, 0), Point2D(sqrt(2)/2, sqrt(2)/2))
"""
def __new__(cls, *args, **kwargs):
if len(args) != 3:
if 'sss' in kwargs:
return _sss(*[simplify(a) for a in kwargs['sss']])
if 'asa' in kwargs:
return _asa(*[simplify(a) for a in kwargs['asa']])
if 'sas' in kwargs:
return _sas(*[simplify(a) for a in kwargs['sas']])
msg = "Triangle instantiates with three points or a valid keyword."
raise GeometryError(msg)
vertices = [Point(a, dim=2, **kwargs) for a in args]
# remove consecutive duplicates
nodup = []
for p in vertices:
if nodup and p == nodup[-1]:
continue
nodup.append(p)
if len(nodup) > 1 and nodup[-1] == nodup[0]:
nodup.pop() # last point was same as first
# remove collinear points
i = -3
while i < len(nodup) - 3 and len(nodup) > 2:
a, b, c = sorted(
[nodup[i], nodup[i + 1], nodup[i + 2]], key=default_sort_key)
if Point.is_collinear(a, b, c):
nodup[i] = a
nodup[i + 1] = None
nodup.pop(i + 1)
i += 1
vertices = list(filter(lambda x: x is not None, nodup))
if len(vertices) == 3:
return GeometryEntity.__new__(cls, *vertices, **kwargs)
elif len(vertices) == 2:
return Segment(*vertices, **kwargs)
else:
return Point(*vertices, **kwargs)
@property
def vertices(self):
"""The triangle's vertices
Returns
=======
vertices : tuple
Each element in the tuple is a Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t.vertices
(Point2D(0, 0), Point2D(4, 0), Point2D(4, 3))
"""
return self.args
def is_similar(t1, t2):
"""Is another triangle similar to this one.
Two triangles are similar if one can be uniformly scaled to the other.
Parameters
==========
other: Triangle
Returns
=======
is_similar : boolean
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t2 = Triangle(Point(0, 0), Point(-4, 0), Point(-4, -3))
>>> t1.is_similar(t2)
True
>>> t2 = Triangle(Point(0, 0), Point(-4, 0), Point(-4, -4))
>>> t1.is_similar(t2)
False
"""
if not isinstance(t2, Polygon):
return False
s1_1, s1_2, s1_3 = [side.length for side in t1.sides]
s2 = [side.length for side in t2.sides]
def _are_similar(u1, u2, u3, v1, v2, v3):
e1 = simplify(u1/v1)
e2 = simplify(u2/v2)
e3 = simplify(u3/v3)
return bool(e1 == e2) and bool(e2 == e3)
# There's only 6 permutations, so write them out
return _are_similar(s1_1, s1_2, s1_3, *s2) or \
_are_similar(s1_1, s1_3, s1_2, *s2) or \
_are_similar(s1_2, s1_1, s1_3, *s2) or \
_are_similar(s1_2, s1_3, s1_1, *s2) or \
_are_similar(s1_3, s1_1, s1_2, *s2) or \
_are_similar(s1_3, s1_2, s1_1, *s2)
def is_equilateral(self):
"""Are all the sides the same length?
Returns
=======
is_equilateral : boolean
See Also
========
sympy.geometry.entity.GeometryEntity.is_similar, RegularPolygon
is_isosceles, is_right, is_scalene
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t1.is_equilateral()
False
>>> from sympy import sqrt
>>> t2 = Triangle(Point(0, 0), Point(10, 0), Point(5, 5*sqrt(3)))
>>> t2.is_equilateral()
True
"""
return not has_variety(s.length for s in self.sides)
def is_isosceles(self):
"""Are two or more of the sides the same length?
Returns
=======
is_isosceles : boolean
See Also
========
is_equilateral, is_right, is_scalene
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(2, 4))
>>> t1.is_isosceles()
True
"""
return has_dups(s.length for s in self.sides)
def is_scalene(self):
"""Are all the sides of the triangle of different lengths?
Returns
=======
is_scalene : boolean
See Also
========
is_equilateral, is_isosceles, is_right
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(1, 4))
>>> t1.is_scalene()
True
"""
return not has_dups(s.length for s in self.sides)
def is_right(self):
"""Is the triangle right-angled.
Returns
=======
is_right : boolean
See Also
========
sympy.geometry.line.LinearEntity.is_perpendicular
is_equilateral, is_isosceles, is_scalene
Examples
========
>>> from sympy.geometry import Triangle, Point
>>> t1 = Triangle(Point(0, 0), Point(4, 0), Point(4, 3))
>>> t1.is_right()
True
"""
s = self.sides
return Segment.is_perpendicular(s[0], s[1]) or \
Segment.is_perpendicular(s[1], s[2]) or \
Segment.is_perpendicular(s[0], s[2])
@property
def altitudes(self):
"""The altitudes of the triangle.
An altitude of a triangle is a segment through a vertex,
perpendicular to the opposite side, with length being the
height of the vertex measured from the line containing the side.
Returns
=======
altitudes : dict
The dictionary consists of keys which are vertices and values
which are Segments.
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment.length
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.altitudes[p1]
Segment2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
s = self.sides
v = self.vertices
return {v[0]: s[1].perpendicular_segment(v[0]),
v[1]: s[2].perpendicular_segment(v[1]),
v[2]: s[0].perpendicular_segment(v[2])}
@property
def orthocenter(self):
"""The orthocenter of the triangle.
The orthocenter is the intersection of the altitudes of a triangle.
It may lie inside, outside or on the triangle.
Returns
=======
orthocenter : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.orthocenter
Point2D(0, 0)
"""
a = self.altitudes
v = self.vertices
return Line(a[v[0]]).intersection(Line(a[v[1]]))[0]
@property
def circumcenter(self):
"""The circumcenter of the triangle
The circumcenter is the center of the circumcircle.
Returns
=======
circumcenter : Point
See Also
========
sympy.geometry.point.Point
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.circumcenter
Point2D(1/2, 1/2)
"""
a, b, c = [x.perpendicular_bisector() for x in self.sides]
if not a.intersection(b):
print(a,b,a.intersection(b))
return a.intersection(b)[0]
@property
def circumradius(self):
"""The radius of the circumcircle of the triangle.
Returns
=======
circumradius : number of Basic instance
See Also
========
sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy import Symbol
>>> from sympy.geometry import Point, Triangle
>>> a = Symbol('a')
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, a)
>>> t = Triangle(p1, p2, p3)
>>> t.circumradius
sqrt(a**2/4 + 1/4)
"""
return Point.distance(self.circumcenter, self.vertices[0])
@property
def circumcircle(self):
"""The circle which passes through the three vertices of the triangle.
Returns
=======
circumcircle : Circle
See Also
========
sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.circumcircle
Circle(Point2D(1/2, 1/2), sqrt(2)/2)
"""
return Circle(self.circumcenter, self.circumradius)
def bisectors(self):
"""The angle bisectors of the triangle.
An angle bisector of a triangle is a straight line through a vertex
which cuts the corresponding angle in half.
Returns
=======
bisectors : dict
Each key is a vertex (Point) and each value is the corresponding
bisector (Segment).
See Also
========
sympy.geometry.point.Point, sympy.geometry.line.Segment
Examples
========
>>> from sympy.geometry import Point, Triangle, Segment
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> from sympy import sqrt
>>> t.bisectors()[p2] == Segment(Point(1, 0), Point(0, sqrt(2) - 1))
True
"""
s = self.sides
v = self.vertices
c = self.incenter
l1 = Segment(v[0], Line(v[0], c).intersection(s[1])[0])
l2 = Segment(v[1], Line(v[1], c).intersection(s[2])[0])
l3 = Segment(v[2], Line(v[2], c).intersection(s[0])[0])
return {v[0]: l1, v[1]: l2, v[2]: l3}
@property
def incenter(self):
"""The center of the incircle.
The incircle is the circle which lies inside the triangle and touches
all three sides.
Returns
=======
incenter : Point
See Also
========
incircle, sympy.geometry.point.Point
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.incenter
Point2D(-sqrt(2)/2 + 1, -sqrt(2)/2 + 1)
"""
s = self.sides
l = Matrix([s[i].length for i in [1, 2, 0]])
p = sum(l)
v = self.vertices
x = simplify(l.dot(Matrix([vi.x for vi in v]))/p)
y = simplify(l.dot(Matrix([vi.y for vi in v]))/p)
return Point(x, y)
@property
def inradius(self):
"""The radius of the incircle.
Returns
=======
inradius : number of Basic instance
See Also
========
incircle, sympy.geometry.ellipse.Circle.radius
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(4, 0), Point(0, 3)
>>> t = Triangle(p1, p2, p3)
>>> t.inradius
1
"""
return simplify(2 * self.area / self.perimeter)
@property
def incircle(self):
"""The incircle of the triangle.
The incircle is the circle which lies inside the triangle and touches
all three sides.
Returns
=======
incircle : Circle
See Also
========
sympy.geometry.ellipse.Circle
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(2, 0), Point(0, 2)
>>> t = Triangle(p1, p2, p3)
>>> t.incircle
Circle(Point2D(-sqrt(2) + 2, -sqrt(2) + 2), -sqrt(2) + 2)
"""
return Circle(self.incenter, self.inradius)
@property
def exradii(self):
"""The radius of excircles of a triangle.
An excircle of the triangle is a circle lying outside the triangle,
tangent to one of its sides and tangent to the extensions of the
other two.
Returns
=======
exradii : dict
See Also
========
sympy.geometry.polygon.Triangle.inradius
Examples
========
The exradius touches the side of the triangle to which it is keyed, e.g.
the exradius touching side 2 is:
>>> from sympy.geometry import Point, Triangle, Segment2D, Point2D
>>> p1, p2, p3 = Point(0, 0), Point(6, 0), Point(0, 2)
>>> t = Triangle(p1, p2, p3)
>>> t.exradii[t.sides[2]]
-2 + sqrt(10)
References
==========
[1] http://mathworld.wolfram.com/Exradius.html
[2] http://mathworld.wolfram.com/Excircles.html
"""
side = self.sides
a = side[0].length
b = side[1].length
c = side[2].length
s = (a+b+c)/2
area = self.area
exradii = {self.sides[0]: simplify(area/(s-a)),
self.sides[1]: simplify(area/(s-b)),
self.sides[2]: simplify(area/(s-c))}
return exradii
@property
def medians(self):
"""The medians of the triangle.
A median of a triangle is a straight line through a vertex and the
midpoint of the opposite side, and divides the triangle into two
equal areas.
Returns
=======
medians : dict
Each key is a vertex (Point) and each value is the median (Segment)
at that point.
See Also
========
sympy.geometry.point.Point.midpoint, sympy.geometry.line.Segment.midpoint
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.medians[p1]
Segment2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
s = self.sides
v = self.vertices
return {v[0]: Segment(v[0], s[1].midpoint),
v[1]: Segment(v[1], s[2].midpoint),
v[2]: Segment(v[2], s[0].midpoint)}
@property
def medial(self):
"""The medial triangle of the triangle.
The triangle which is formed from the midpoints of the three sides.
Returns
=======
medial : Triangle
See Also
========
sympy.geometry.line.Segment.midpoint
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.medial
Triangle(Point2D(1/2, 0), Point2D(1/2, 1/2), Point2D(0, 1/2))
"""
s = self.sides
return Triangle(s[0].midpoint, s[1].midpoint, s[2].midpoint)
@property
def nine_point_circle(self):
"""The nine-point circle of the triangle.
Nine-point circle is the circumcircle of the medial triangle, which
passes through the feet of altitudes and the middle points of segments
connecting the vertices and the orthocenter.
Returns
=======
nine_point_circle : Circle
See also
========
sympy.geometry.line.Segment.midpoint
sympy.geometry.polygon.Triangle.medial
sympy.geometry.polygon.Triangle.orthocenter
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.nine_point_circle
Circle(Point2D(1/4, 1/4), sqrt(2)/4)
"""
return Circle(*self.medial.vertices)
@property
def eulerline(self):
"""The Euler line of the triangle.
The line which passes through circumcenter, centroid and orthocenter.
Returns
=======
eulerline : Line (or Point for equilateral triangles in which case all
centers coincide)
Examples
========
>>> from sympy.geometry import Point, Triangle
>>> p1, p2, p3 = Point(0, 0), Point(1, 0), Point(0, 1)
>>> t = Triangle(p1, p2, p3)
>>> t.eulerline
Line2D(Point2D(0, 0), Point2D(1/2, 1/2))
"""
if self.is_equilateral():
return self.orthocenter
return Line(self.orthocenter, self.circumcenter)
def rad(d):
"""Return the radian value for the given degrees (pi = 180 degrees)."""
return d*pi/180
def deg(r):
"""Return the degree value for the given radians (pi = 180 degrees)."""
return r/pi*180
def _slope(d):
rv = tan(rad(d))
return rv
def _asa(d1, l, d2):
"""Return triangle having side with length l on the x-axis."""
xy = Line((0, 0), slope=_slope(d1)).intersection(
Line((l, 0), slope=_slope(180 - d2)))[0]
return Triangle((0, 0), (l, 0), xy)
def _sss(l1, l2, l3):
"""Return triangle having side of length l1 on the x-axis."""
c1 = Circle((0, 0), l3)
c2 = Circle((l1, 0), l2)
inter = [a for a in c1.intersection(c2) if a.y.is_nonnegative]
if not inter:
return None
pt = inter[0]
return Triangle((0, 0), (l1, 0), pt)
def _sas(l1, d, l2):
"""Return triangle having side with length l2 on the x-axis."""
p1 = Point(0, 0)
p2 = Point(l2, 0)
p3 = Point(cos(rad(d))*l1, sin(rad(d))*l1)
return Triangle(p1, p2, p3)
|
76a5d1e89ba775cf354cf298b902104ad3514aea612291e9cd78c422aaba282f
|
"""
This module implements Pauli algebra by subclassing Symbol. Only algebraic
properties of Pauli matrices are used (we don't use the Matrix class).
See the documentation to the class Pauli for examples.
References
~~~~~~~~~~
.. [1] https://en.wikipedia.org/wiki/Pauli_matrices
"""
from __future__ import print_function, division
from sympy import Symbol, I, Mul, Pow, Add
from sympy.physics.quantum import TensorProduct
__all__ = ['evaluate_pauli_product']
def delta(i, j):
"""
Returns 1 if i == j, else 0.
This is used in the multiplication of Pauli matrices.
Examples
========
>>> from sympy.physics.paulialgebra import delta
>>> delta(1, 1)
1
>>> delta(2, 3)
0
"""
if i == j:
return 1
else:
return 0
def epsilon(i, j, k):
"""
Return 1 if i,j,k is equal to (1,2,3), (2,3,1), or (3,1,2);
-1 if i,j,k is equal to (1,3,2), (3,2,1), or (2,1,3);
else return 0.
This is used in the multiplication of Pauli matrices.
Examples
========
>>> from sympy.physics.paulialgebra import epsilon
>>> epsilon(1, 2, 3)
1
>>> epsilon(1, 3, 2)
-1
"""
if (i, j, k) in [(1, 2, 3), (2, 3, 1), (3, 1, 2)]:
return 1
elif (i, j, k) in [(1, 3, 2), (3, 2, 1), (2, 1, 3)]:
return -1
else:
return 0
class Pauli(Symbol):
"""The class representing algebraic properties of Pauli matrices
If the left multiplication of symbol or number with Pauli matrix is needed,
please use parentheses to separate Pauli and symbolic multiplication
(for example: 2*I*(Pauli(3)*Pauli(2)))
Another variant is to use evaluate_pauli_product function to evaluate
the product of Pauli matrices and other symbols (with commutative
multiply rules)
See Also
=======
evaluate_pauli_product
Examples
========
>>> from sympy.physics.paulialgebra import Pauli
>>> Pauli(1)
sigma1
>>> Pauli(1)*Pauli(2)
I*sigma3
>>> Pauli(1)*Pauli(1)
1
>>> Pauli(3)**4
1
>>> Pauli(1)*Pauli(2)*Pauli(3)
I
>>> from sympy import I
>>> I*(Pauli(2)*Pauli(3))
-sigma1
>>> from sympy.physics.paulialgebra import evaluate_pauli_product
>>> f = I*Pauli(2)*Pauli(3)
>>> f
I*sigma2*sigma3
>>> evaluate_pauli_product(f)
-sigma1
"""
__slots__ = ["i"]
def __new__(cls, i):
if not i in [1, 2, 3]:
raise IndexError("Invalid Pauli index")
obj = Symbol.__new__(cls, "sigma%d" % i, commutative=False, hermitian=True)
obj.i = i
return obj
def __getnewargs__(self):
return (self.i,)
# FIXME don't work for -I*Pauli(2)*Pauli(3)
def __mul__(self, other):
if isinstance(other, Pauli):
j = self.i
k = other.i
return delta(j, k) \
+ I*epsilon(j, k, 1)*Pauli(1) \
+ I*epsilon(j, k, 2)*Pauli(2) \
+ I*epsilon(j, k, 3)*Pauli(3)
return super(Pauli, self).__mul__(other)
def _eval_power(b, e):
if e.is_Integer and e.is_positive:
return super(Pauli, b).__pow__(int(e) % 2)
def evaluate_pauli_product(arg):
'''Help function to evaluate Pauli matrices product
with symbolic objects
Parameters
==========
arg: symbolic expression that contains Paulimatrices
Examples
========
>>> from sympy.physics.paulialgebra import Pauli, evaluate_pauli_product
>>> from sympy import I
>>> evaluate_pauli_product(I*Pauli(1)*Pauli(2))
-sigma3
>>> from sympy.abc import x,y
>>> evaluate_pauli_product(x**2*Pauli(2)*Pauli(1))
-I*x**2*sigma3
'''
start = arg
end = arg
if isinstance(arg, Pow) and isinstance(arg.args[0], Pauli):
if arg.args[1].is_odd:
return arg.args[0]
else:
return 1
if isinstance(arg, Add):
return Add(*[evaluate_pauli_product(part) for part in arg.args])
if isinstance(arg, TensorProduct):
return TensorProduct(*[evaluate_pauli_product(part) for part in arg.args])
elif not(isinstance(arg, Mul)):
return arg
while ((not(start == end)) | ((start == arg) & (end == arg))):
start = end
tmp = start.as_coeff_mul()
sigma_product = 1
com_product = 1
keeper = 1
for el in tmp[1]:
if isinstance(el, Pauli):
sigma_product *= el
elif not(el.is_commutative):
if isinstance(el, Pow) and isinstance(el.args[0], Pauli):
if el.args[1].is_odd:
sigma_product *= el.args[0]
elif isinstance(el, TensorProduct):
keeper = keeper*sigma_product*\
TensorProduct(
*[evaluate_pauli_product(part) for part in el.args]
)
sigma_product = 1
else:
keeper = keeper*sigma_product*el
sigma_product = 1
else:
com_product *= el
end = (tmp[0]*keeper*sigma_product*com_product)
if end == arg: break
return end
|
60a9f3a7e9cb9cb0e481c4efeb7b4ee1001a6dc4bdb6fb29b4bfeb81b76e79df
|
from sympy.utilities.exceptions import SymPyDeprecationWarning
from sympy.core.core import BasicMeta, Registry, all_classes
class ClassRegistry(Registry):
"""
Namespace for SymPy classes
This is needed to avoid problems with cyclic imports.
To get a SymPy class, use `C.<class_name>` e.g. `C.Rational`, `C.Add`.
For performance reasons, this is coupled with a set `all_classes` holding
the classes, which should not be modified directly.
"""
__slots__ = []
def __setattr__(self, name, cls):
Registry.__setattr__(self, name, cls)
all_classes.add(cls)
def __delattr__(self, name):
cls = getattr(self, name)
Registry.__delattr__(self, name)
# The same class could have different names, so make sure
# it's really gone from C before removing it from all_classes.
if cls not in self.__class__.__dict__.itervalues():
all_classes.remove(cls)
def __getattr__(self, name):
# Warning on hasattr(C, '__wrapped__') leadds to warnings during test
# collection when running doctests under pytest.
if name != '__wrapped__':
SymPyDeprecationWarning(
feature='C, including its class ClassRegistry,',
last_supported_version='1.0',
useinstead='direct imports from the defining module',
issue=9371,
deprecated_since_version='1.0').warn(stacklevel=2)
return any(cls.__name__ == name for cls in all_classes)
@property
def _sympy_(self):
# until C is deprecated, any sympification of an expression
# with C when C has not been defined can raise this error
# since the user is trying to use C like a symbol -- and if
# we get here, it hasn't been defined as a symbol
raise NameError("name 'C' is not defined as a Symbol")
C = ClassRegistry()
C.BasicMeta = BasicMeta
|
31e9098e9c64dc9e732d78c0891d334df4304a9eebfa3c2a2c64a58c9a2ccdbe
|
"""
Boolean algebra module for SymPy
"""
from __future__ import print_function, division
from collections import defaultdict
from itertools import combinations, product
from sympy.core.add import Add
from sympy.core.basic import Basic, as_Basic
from sympy.core.cache import cacheit
from sympy.core.numbers import Number, oo
from sympy.core.operations import LatticeOp
from sympy.core.function import Application, Derivative, count_ops
from sympy.core.compatibility import (ordered, range, with_metaclass,
as_int, reduce)
from sympy.core.sympify import converter, _sympify, sympify
from sympy.core.singleton import Singleton, S
from sympy.utilities.misc import filldedent
from sympy.utilities.iterables import sift
def as_Boolean(e):
"""Like bool, return the Boolean value of an expression, e,
which can be any instance of Boolean or bool.
Examples
========
>>> from sympy import true, false, nan
>>> from sympy.logic.boolalg import as_Boolean
>>> from sympy.abc import x
>>> as_Boolean(1) is true
True
>>> as_Boolean(x)
x
>>> as_Boolean(2)
Traceback (most recent call last):
...
TypeError: expecting bool or Boolean, not `2`.
"""
from sympy.core.symbol import Symbol
if e == True:
return S.true
if e == False:
return S.false
if isinstance(e, Symbol):
z = e.is_zero
if z is None:
return e
return S.false if z else S.true
if isinstance(e, Boolean):
return e
raise TypeError('expecting bool or Boolean, not `%s`.' % e)
class Boolean(Basic):
"""A boolean object is an object for which logic operations make sense."""
__slots__ = []
def __and__(self, other):
"""Overloading for & operator"""
return And(self, other)
__rand__ = __and__
def __or__(self, other):
"""Overloading for |"""
return Or(self, other)
__ror__ = __or__
def __invert__(self):
"""Overloading for ~"""
return Not(self)
def __rshift__(self, other):
"""Overloading for >>"""
return Implies(self, other)
def __lshift__(self, other):
"""Overloading for <<"""
return Implies(other, self)
__rrshift__ = __lshift__
__rlshift__ = __rshift__
def __xor__(self, other):
return Xor(self, other)
__rxor__ = __xor__
def equals(self, other):
"""
Returns True if the given formulas have the same truth table.
For two formulas to be equal they must have the same literals.
Examples
========
>>> from sympy.abc import A, B, C
>>> from sympy.logic.boolalg import And, Or, Not
>>> (A >> B).equals(~B >> ~A)
True
>>> Not(And(A, B, C)).equals(And(Not(A), Not(B), Not(C)))
False
>>> Not(And(A, Not(A))).equals(Or(B, Not(B)))
False
"""
from sympy.logic.inference import satisfiable
from sympy.core.relational import Relational
if self.has(Relational) or other.has(Relational):
raise NotImplementedError('handling of relationals')
return self.atoms() == other.atoms() and \
not satisfiable(Not(Equivalent(self, other)))
def to_nnf(self, simplify=True):
# override where necessary
return self
def as_set(self):
"""
Rewrites Boolean expression in terms of real sets.
Examples
========
>>> from sympy import Symbol, Eq, Or, And
>>> x = Symbol('x', real=True)
>>> Eq(x, 0).as_set()
{0}
>>> (x > 0).as_set()
Interval.open(0, oo)
>>> And(-2 < x, x < 2).as_set()
Interval.open(-2, 2)
>>> Or(x < -2, 2 < x).as_set()
Union(Interval.open(-oo, -2), Interval.open(2, oo))
"""
from sympy.calculus.util import periodicity
from sympy.core.relational import Relational
free = self.free_symbols
if len(free) == 1:
x = free.pop()
reps = {}
for r in self.atoms(Relational):
if periodicity(r, x) not in (0, None):
s = r._eval_as_set()
if s in (S.EmptySet, S.UniversalSet, S.Reals):
reps[r] = s.as_relational(x)
continue
raise NotImplementedError(filldedent('''
as_set is not implemented for relationals
with periodic solutions
'''))
return self.subs(reps)._eval_as_set()
else:
raise NotImplementedError("Sorry, as_set has not yet been"
" implemented for multivariate"
" expressions")
@property
def binary_symbols(self):
from sympy.core.relational import Eq, Ne
return set().union(*[i.binary_symbols for i in self.args
if i.is_Boolean or i.is_Symbol
or isinstance(i, (Eq, Ne))])
class BooleanAtom(Boolean):
"""
Base class of BooleanTrue and BooleanFalse.
"""
is_Boolean = True
is_Atom = True
_op_priority = 11 # higher than Expr
def simplify(self, *a, **kw):
return self
def expand(self, *a, **kw):
return self
@property
def canonical(self):
return self
def _noop(self, other=None):
raise TypeError('BooleanAtom not allowed in this context.')
__add__ = _noop
__radd__ = _noop
__sub__ = _noop
__rsub__ = _noop
__mul__ = _noop
__rmul__ = _noop
__pow__ = _noop
__rpow__ = _noop
__rdiv__ = _noop
__truediv__ = _noop
__div__ = _noop
__rtruediv__ = _noop
__mod__ = _noop
__rmod__ = _noop
_eval_power = _noop
# /// drop when Py2 is no longer supported
def __lt__(self, other):
from sympy.utilities.misc import filldedent
raise TypeError(filldedent('''
A Boolean argument can only be used in
Eq and Ne; all other relationals expect
real expressions.
'''))
__le__ = __lt__
__gt__ = __lt__
__ge__ = __lt__
# \\\
class BooleanTrue(with_metaclass(Singleton, BooleanAtom)):
"""
SymPy version of True, a singleton that can be accessed via S.true.
This is the SymPy version of True, for use in the logic module. The
primary advantage of using true instead of True is that shorthand boolean
operations like ~ and >> will work as expected on this class, whereas with
True they act bitwise on 1. Functions in the logic module will return this
class when they evaluate to true.
Notes
=====
There is liable to be some confusion as to when ``True`` should
be used and when ``S.true`` should be used in various contexts
throughout SymPy. An important thing to remember is that
``sympify(True)`` returns ``S.true``. This means that for the most
part, you can just use ``True`` and it will automatically be converted
to ``S.true`` when necessary, similar to how you can generally use 1
instead of ``S.One``.
The rule of thumb is:
"If the boolean in question can be replaced by an arbitrary symbolic
``Boolean``, like ``Or(x, y)`` or ``x > 1``, use ``S.true``.
Otherwise, use ``True``"
In other words, use ``S.true`` only on those contexts where the
boolean is being used as a symbolic representation of truth.
For example, if the object ends up in the ``.args`` of any expression,
then it must necessarily be ``S.true`` instead of ``True``, as
elements of ``.args`` must be ``Basic``. On the other hand,
``==`` is not a symbolic operation in SymPy, since it always returns
``True`` or ``False``, and does so in terms of structural equality
rather than mathematical, so it should return ``True``. The assumptions
system should use ``True`` and ``False``. Aside from not satisfying
the above rule of thumb, the
assumptions system uses a three-valued logic (``True``, ``False``, ``None``),
whereas ``S.true`` and ``S.false`` represent a two-valued logic. When in
doubt, use ``True``.
"``S.true == True is True``."
While "``S.true is True``" is ``False``, "``S.true == True``"
is ``True``, so if there is any doubt over whether a function or
expression will return ``S.true`` or ``True``, just use ``==``
instead of ``is`` to do the comparison, and it will work in either
case. Finally, for boolean flags, it's better to just use ``if x``
instead of ``if x is True``. To quote PEP 8:
Don't compare boolean values to ``True`` or ``False``
using ``==``.
* Yes: ``if greeting:``
* No: ``if greeting == True:``
* Worse: ``if greeting is True:``
Examples
========
>>> from sympy import sympify, true, false, Or
>>> sympify(True)
True
>>> _ is True, _ is true
(False, True)
>>> Or(true, false)
True
>>> _ is true
True
Python operators give a boolean result for true but a
bitwise result for True
>>> ~true, ~True
(False, -2)
>>> true >> true, True >> True
(True, 0)
Python operators give a boolean result for true but a
bitwise result for True
>>> ~true, ~True
(False, -2)
>>> true >> true, True >> True
(True, 0)
See Also
========
sympy.logic.boolalg.BooleanFalse
"""
def __nonzero__(self):
return True
__bool__ = __nonzero__
def __hash__(self):
return hash(True)
def as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import true
>>> true.as_set()
UniversalSet()
"""
return S.UniversalSet
class BooleanFalse(with_metaclass(Singleton, BooleanAtom)):
"""
SymPy version of False, a singleton that can be accessed via S.false.
This is the SymPy version of False, for use in the logic module. The
primary advantage of using false instead of False is that shorthand boolean
operations like ~ and >> will work as expected on this class, whereas with
False they act bitwise on 0. Functions in the logic module will return this
class when they evaluate to false.
Notes
======
See note in :py:class`sympy.logic.boolalg.BooleanTrue`
Examples
========
>>> from sympy import sympify, true, false, Or
>>> sympify(False)
False
>>> _ is False, _ is false
(False, True)
>>> Or(true, false)
True
>>> _ is true
True
Python operators give a boolean result for false but a
bitwise result for False
>>> ~false, ~False
(True, -1)
>>> false >> false, False >> False
(True, 0)
See Also
========
sympy.logic.boolalg.BooleanTrue
"""
def __nonzero__(self):
return False
__bool__ = __nonzero__
def __hash__(self):
return hash(False)
def as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import false
>>> false.as_set()
EmptySet()
"""
return S.EmptySet
true = BooleanTrue()
false = BooleanFalse()
# We want S.true and S.false to work, rather than S.BooleanTrue and
# S.BooleanFalse, but making the class and instance names the same causes some
# major issues (like the inability to import the class directly from this
# file).
S.true = true
S.false = false
converter[bool] = lambda x: S.true if x else S.false
class BooleanFunction(Application, Boolean):
"""Boolean function is a function that lives in a boolean space
It is used as base class for And, Or, Not, etc.
"""
is_Boolean = True
def _eval_simplify(self, ratio, measure, rational, inverse):
rv = self.func(*[a._eval_simplify(ratio=ratio, measure=measure,
rational=rational, inverse=inverse) for a in self.args])
return simplify_logic(rv)
def simplify(self, ratio=1.7, measure=count_ops, rational=False, inverse=False):
return self._eval_simplify(ratio, measure, rational, inverse)
# /// drop when Py2 is no longer supported
def __lt__(self, other):
from sympy.utilities.misc import filldedent
raise TypeError(filldedent('''
A Boolean argument can only be used in
Eq and Ne; all other relationals expect
real expressions.
'''))
__le__ = __lt__
__ge__ = __lt__
__gt__ = __lt__
# \\\
@classmethod
def binary_check_and_simplify(self, *args):
from sympy.core.relational import Relational, Eq, Ne
args = [as_Boolean(i) for i in args]
bin = set().union(*[i.binary_symbols for i in args])
rel = set().union(*[i.atoms(Relational) for i in args])
reps = {}
for x in bin:
for r in rel:
if x in bin and x in r.free_symbols:
if isinstance(r, (Eq, Ne)):
if not (
S.true in r.args or
S.false in r.args):
reps[r] = S.false
else:
raise TypeError(filldedent('''
Incompatible use of binary symbol `%s` as a
real variable in `%s`
''' % (x, r)))
return [i.subs(reps) for i in args]
def to_nnf(self, simplify=True):
return self._to_nnf(*self.args, simplify=simplify)
@classmethod
def _to_nnf(cls, *args, **kwargs):
simplify = kwargs.get('simplify', True)
argset = set([])
for arg in args:
if not is_literal(arg):
arg = arg.to_nnf(simplify)
if simplify:
if isinstance(arg, cls):
arg = arg.args
else:
arg = (arg,)
for a in arg:
if Not(a) in argset:
return cls.zero
argset.add(a)
else:
argset.add(arg)
return cls(*argset)
# the diff method below is copied from Expr class
def diff(self, *symbols, **assumptions):
assumptions.setdefault("evaluate", True)
return Derivative(self, *symbols, **assumptions)
def _eval_derivative(self, x):
from sympy.core.relational import Eq, Relational
from sympy.functions.elementary.piecewise import Piecewise
if x in self.binary_symbols:
return Piecewise(
(0, Eq(self.subs(x, 0), self.subs(x, 1))),
(1, True))
elif x in self.free_symbols:
# not implemented, see https://www.encyclopediaofmath.org/
# index.php/Boolean_differential_calculus
pass
else:
return S.Zero
class And(LatticeOp, BooleanFunction):
"""
Logical AND function.
It evaluates its arguments in order, giving False immediately
if any of them are False, and True if they are all True.
Examples
========
>>> from sympy.core import symbols
>>> from sympy.abc import x, y
>>> from sympy.logic.boolalg import And
>>> x & y
x & y
Notes
=====
The ``&`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
and. Hence, ``And(a, b)`` and ``a & b`` will return different things if
``a`` and ``b`` are integers.
>>> And(x, y).subs(x, 1)
y
"""
zero = false
identity = true
nargs = None
@classmethod
def _new_args_filter(cls, args):
newargs = []
rel = []
args = BooleanFunction.binary_check_and_simplify(*args)
for x in reversed(args):
if x.is_Relational:
c = x.canonical
if c in rel:
continue
nc = (~c).canonical
if any(r == nc for r in rel):
return [S.false]
rel.append(c)
newargs.append(x)
return LatticeOp._new_args_filter(newargs, And)
def _eval_simplify(self, ratio, measure, rational, inverse):
from sympy.core.relational import Equality, Relational
from sympy.solvers.solveset import linear_coeffs
# standard simplify
rv = super(And, self)._eval_simplify(
ratio, measure, rational, inverse)
if not isinstance(rv, And):
return rv
# simplify args that are equalities involving
# symbols so x == 0 & x == y -> x==0 & y == 0
Rel, nonRel = sift(rv.args, lambda i: isinstance(i, Relational), binary=True)
if not Rel:
return rv
eqs, other = sift(Rel, lambda i: isinstance(i, Equality), binary=True)
if not eqs:
return rv
reps = {}
sifted = {}
if eqs:
# group by length of free symbols
sifted = sift(ordered([
(i.free_symbols, i) for i in eqs]),
lambda x: len(x[0]))
eqs = []
while 1 in sifted:
for free, e in sifted.pop(1):
x = free.pop()
if e.lhs != x or x in e.rhs.free_symbols:
try:
m, b = linear_coeffs(
e.rewrite(Add, evaluate=False), x)
enew = e.func(x, -b/m)
if measure(enew) <= ratio*measure(e):
e = enew
else:
eqs.append(e)
continue
except ValueError:
pass
if x in reps:
eqs.append(e.func(e.rhs, reps[x]))
else:
reps[x] = e.rhs
eqs.append(e)
resifted = defaultdict(list)
for k in sifted:
for f, e in sifted[k]:
e = e.subs(reps)
f = e.free_symbols
resifted[len(f)].append((f, e))
sifted = resifted
for k in sifted:
eqs.extend([e for f, e in sifted[k]])
other = [ei.subs(reps) for ei in other]
rv = rv.func(*([i.canonical for i in (eqs + other)] + nonRel))
return rv
def _eval_as_set(self):
from sympy.sets.sets import Intersection
return Intersection(*[arg.as_set() for arg in self.args])
class Or(LatticeOp, BooleanFunction):
"""
Logical OR function
It evaluates its arguments in order, giving True immediately
if any of them are True, and False if they are all False.
Examples
========
>>> from sympy.core import symbols
>>> from sympy.abc import x, y
>>> from sympy.logic.boolalg import Or
>>> x | y
x | y
Notes
=====
The ``|`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
or. Hence, ``Or(a, b)`` and ``a | b`` will return different things if
``a`` and ``b`` are integers.
>>> Or(x, y).subs(x, 0)
y
"""
zero = true
identity = false
@classmethod
def _new_args_filter(cls, args):
newargs = []
rel = []
args = BooleanFunction.binary_check_and_simplify(*args)
for x in args:
if x.is_Relational:
c = x.canonical
if c in rel:
continue
nc = (~c).canonical
if any(r == nc for r in rel):
return [S.true]
rel.append(c)
newargs.append(x)
return LatticeOp._new_args_filter(newargs, Or)
def _eval_as_set(self):
from sympy.sets.sets import Union
return Union(*[arg.as_set() for arg in self.args])
class Not(BooleanFunction):
"""
Logical Not function (negation)
Returns True if the statement is False
Returns False if the statement is True
Examples
========
>>> from sympy.logic.boolalg import Not, And, Or
>>> from sympy.abc import x, A, B
>>> Not(True)
False
>>> Not(False)
True
>>> Not(And(True, False))
True
>>> Not(Or(True, False))
False
>>> Not(And(And(True, x), Or(x, False)))
~x
>>> ~x
~x
>>> Not(And(Or(A, B), Or(~A, ~B)))
~((A | B) & (~A | ~B))
Notes
=====
- The ``~`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise
not. In particular, ``~a`` and ``Not(a)`` will be different if ``a`` is
an integer. Furthermore, since bools in Python subclass from ``int``,
``~True`` is the same as ``~1`` which is ``-2``, which has a boolean
value of True. To avoid this issue, use the SymPy boolean types
``true`` and ``false``.
>>> from sympy import true
>>> ~True
-2
>>> ~true
False
"""
is_Not = True
@classmethod
def eval(cls, arg):
from sympy import (
Equality, GreaterThan, LessThan,
StrictGreaterThan, StrictLessThan, Unequality)
if isinstance(arg, Number) or arg in (True, False):
return false if arg else true
if arg.is_Not:
return arg.args[0]
# Simplify Relational objects.
if isinstance(arg, Equality):
return Unequality(*arg.args)
if isinstance(arg, Unequality):
return Equality(*arg.args)
if isinstance(arg, StrictLessThan):
return GreaterThan(*arg.args)
if isinstance(arg, StrictGreaterThan):
return LessThan(*arg.args)
if isinstance(arg, LessThan):
return StrictGreaterThan(*arg.args)
if isinstance(arg, GreaterThan):
return StrictLessThan(*arg.args)
def _eval_as_set(self):
"""
Rewrite logic operators and relationals in terms of real sets.
Examples
========
>>> from sympy import Not, Symbol
>>> x = Symbol('x')
>>> Not(x > 0).as_set()
Interval(-oo, 0)
"""
return self.args[0].as_set().complement(S.Reals)
def to_nnf(self, simplify=True):
if is_literal(self):
return self
expr = self.args[0]
func, args = expr.func, expr.args
if func == And:
return Or._to_nnf(*[~arg for arg in args], simplify=simplify)
if func == Or:
return And._to_nnf(*[~arg for arg in args], simplify=simplify)
if func == Implies:
a, b = args
return And._to_nnf(a, ~b, simplify=simplify)
if func == Equivalent:
return And._to_nnf(Or(*args), Or(*[~arg for arg in args]), simplify=simplify)
if func == Xor:
result = []
for i in range(1, len(args)+1, 2):
for neg in combinations(args, i):
clause = [~s if s in neg else s for s in args]
result.append(Or(*clause))
return And._to_nnf(*result, simplify=simplify)
if func == ITE:
a, b, c = args
return And._to_nnf(Or(a, ~c), Or(~a, ~b), simplify=simplify)
raise ValueError("Illegal operator %s in expression" % func)
class Xor(BooleanFunction):
"""
Logical XOR (exclusive OR) function.
Returns True if an odd number of the arguments are True and the rest are
False.
Returns False if an even number of the arguments are True and the rest are
False.
Examples
========
>>> from sympy.logic.boolalg import Xor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Xor(True, False)
True
>>> Xor(True, True)
False
>>> Xor(True, False, True, True, False)
True
>>> Xor(True, False, True, False)
False
>>> x ^ y
Xor(x, y)
Notes
=====
The ``^`` operator is provided as a convenience, but note that its use
here is different from its normal use in Python, which is bitwise xor. In
particular, ``a ^ b`` and ``Xor(a, b)`` will be different if ``a`` and
``b`` are integers.
>>> Xor(x, y).subs(y, 0)
x
"""
def __new__(cls, *args, **kwargs):
argset = set([])
obj = super(Xor, cls).__new__(cls, *args, **kwargs)
for arg in obj._args:
if isinstance(arg, Number) or arg in (True, False):
if arg:
arg = true
else:
continue
if isinstance(arg, Xor):
for a in arg.args:
argset.remove(a) if a in argset else argset.add(a)
elif arg in argset:
argset.remove(arg)
else:
argset.add(arg)
rel = [(r, r.canonical, (~r).canonical) for r in argset if r.is_Relational]
odd = False # is number of complimentary pairs odd? start 0 -> False
remove = []
for i, (r, c, nc) in enumerate(rel):
for j in range(i + 1, len(rel)):
rj, cj = rel[j][:2]
if cj == nc:
odd = ~odd
break
elif cj == c:
break
else:
continue
remove.append((r, rj))
if odd:
argset.remove(true) if true in argset else argset.add(true)
for a, b in remove:
argset.remove(a)
argset.remove(b)
if len(argset) == 0:
return false
elif len(argset) == 1:
return argset.pop()
elif True in argset:
argset.remove(True)
return Not(Xor(*argset))
else:
obj._args = tuple(ordered(argset))
obj._argset = frozenset(argset)
return obj
@property
@cacheit
def args(self):
return tuple(ordered(self._argset))
def to_nnf(self, simplify=True):
args = []
for i in range(0, len(self.args)+1, 2):
for neg in combinations(self.args, i):
clause = [~s if s in neg else s for s in self.args]
args.append(Or(*clause))
return And._to_nnf(*args, simplify=simplify)
class Nand(BooleanFunction):
"""
Logical NAND function.
It evaluates its arguments in order, giving True immediately if any
of them are False, and False if they are all True.
Returns True if any of the arguments are False
Returns False if all arguments are True
Examples
========
>>> from sympy.logic.boolalg import Nand
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Nand(False, True)
True
>>> Nand(True, True)
False
>>> Nand(x, y)
~(x & y)
"""
@classmethod
def eval(cls, *args):
return Not(And(*args))
class Nor(BooleanFunction):
"""
Logical NOR function.
It evaluates its arguments in order, giving False immediately if any
of them are True, and True if they are all False.
Returns False if any argument is True
Returns True if all arguments are False
Examples
========
>>> from sympy.logic.boolalg import Nor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Nor(True, False)
False
>>> Nor(True, True)
False
>>> Nor(False, True)
False
>>> Nor(False, False)
True
>>> Nor(x, y)
~(x | y)
"""
@classmethod
def eval(cls, *args):
return Not(Or(*args))
class Xnor(BooleanFunction):
"""
Logical XNOR function.
Returns False if an odd number of the arguments are True and the rest are
False.
Returns True if an even number of the arguments are True and the rest are
False.
Examples
========
>>> from sympy.logic.boolalg import Xnor
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Xnor(True, False)
False
>>> Xnor(True, True)
True
>>> Xnor(True, False, True, True, False)
False
>>> Xnor(True, False, True, False)
True
"""
@classmethod
def eval(cls, *args):
return Not(Xor(*args))
class Implies(BooleanFunction):
"""
Logical implication.
A implies B is equivalent to !A v B
Accepts two Boolean arguments; A and B.
Returns False if A is True and B is False
Returns True otherwise.
Examples
========
>>> from sympy.logic.boolalg import Implies
>>> from sympy import symbols
>>> x, y = symbols('x y')
>>> Implies(True, False)
False
>>> Implies(False, False)
True
>>> Implies(True, True)
True
>>> Implies(False, True)
True
>>> x >> y
Implies(x, y)
>>> y << x
Implies(x, y)
Notes
=====
The ``>>`` and ``<<`` operators are provided as a convenience, but note
that their use here is different from their normal use in Python, which is
bit shifts. Hence, ``Implies(a, b)`` and ``a >> b`` will return different
things if ``a`` and ``b`` are integers. In particular, since Python
considers ``True`` and ``False`` to be integers, ``True >> True`` will be
the same as ``1 >> 1``, i.e., 0, which has a truth value of False. To
avoid this issue, use the SymPy objects ``true`` and ``false``.
>>> from sympy import true, false
>>> True >> False
1
>>> true >> false
False
"""
@classmethod
def eval(cls, *args):
try:
newargs = []
for x in args:
if isinstance(x, Number) or x in (0, 1):
newargs.append(True if x else False)
else:
newargs.append(x)
A, B = newargs
except ValueError:
raise ValueError(
"%d operand(s) used for an Implies "
"(pairs are required): %s" % (len(args), str(args)))
if A == True or A == False or B == True or B == False:
return Or(Not(A), B)
elif A == B:
return S.true
elif A.is_Relational and B.is_Relational:
if A.canonical == B.canonical:
return S.true
if (~A).canonical == B.canonical:
return B
else:
return Basic.__new__(cls, *args)
def to_nnf(self, simplify=True):
a, b = self.args
return Or._to_nnf(~a, b, simplify=simplify)
class Equivalent(BooleanFunction):
"""
Equivalence relation.
Equivalent(A, B) is True iff A and B are both True or both False
Returns True if all of the arguments are logically equivalent.
Returns False otherwise.
Examples
========
>>> from sympy.logic.boolalg import Equivalent, And
>>> from sympy.abc import x, y
>>> Equivalent(False, False, False)
True
>>> Equivalent(True, False, False)
False
>>> Equivalent(x, And(x, True))
True
"""
def __new__(cls, *args, **options):
from sympy.core.relational import Relational
args = [_sympify(arg) for arg in args]
argset = set(args)
for x in args:
if isinstance(x, Number) or x in [True, False]: # Includes 0, 1
argset.discard(x)
argset.add(True if x else False)
rel = []
for r in argset:
if isinstance(r, Relational):
rel.append((r, r.canonical, (~r).canonical))
remove = []
for i, (r, c, nc) in enumerate(rel):
for j in range(i + 1, len(rel)):
rj, cj = rel[j][:2]
if cj == nc:
return false
elif cj == c:
remove.append((r, rj))
break
for a, b in remove:
argset.remove(a)
argset.remove(b)
argset.add(True)
if len(argset) <= 1:
return true
if True in argset:
argset.discard(True)
return And(*argset)
if False in argset:
argset.discard(False)
return And(*[~arg for arg in argset])
_args = frozenset(argset)
obj = super(Equivalent, cls).__new__(cls, _args)
obj._argset = _args
return obj
@property
@cacheit
def args(self):
return tuple(ordered(self._argset))
def to_nnf(self, simplify=True):
args = []
for a, b in zip(self.args, self.args[1:]):
args.append(Or(~a, b))
args.append(Or(~self.args[-1], self.args[0]))
return And._to_nnf(*args, simplify=simplify)
class ITE(BooleanFunction):
"""
If then else clause.
ITE(A, B, C) evaluates and returns the result of B if A is true
else it returns the result of C. All args must be Booleans.
Examples
========
>>> from sympy.logic.boolalg import ITE, And, Xor, Or
>>> from sympy.abc import x, y, z
>>> ITE(True, False, True)
False
>>> ITE(Or(True, False), And(True, True), Xor(True, True))
True
>>> ITE(x, y, z)
ITE(x, y, z)
>>> ITE(True, x, y)
x
>>> ITE(False, x, y)
y
>>> ITE(x, y, y)
y
Trying to use non-Boolean args will generate a TypeError:
>>> ITE(True, [], ())
Traceback (most recent call last):
...
TypeError: expecting bool, Boolean or ITE, not `[]`
"""
def __new__(cls, *args, **kwargs):
from sympy.core.relational import Eq, Ne
if len(args) != 3:
raise ValueError('expecting exactly 3 args')
a, b, c = args
# check use of binary symbols
if isinstance(a, (Eq, Ne)):
# in this context, we can evaluate the Eq/Ne
# if one arg is a binary symbol and the other
# is true/false
b, c = map(as_Boolean, (b, c))
bin = set().union(*[i.binary_symbols for i in (b, c)])
if len(set(a.args) - bin) == 1:
# one arg is a binary_symbols
_a = a
if a.lhs is S.true:
a = a.rhs
elif a.rhs is S.true:
a = a.lhs
elif a.lhs is S.false:
a = ~a.rhs
elif a.rhs is S.false:
a = ~a.lhs
else:
# binary can only equal True or False
a = S.false
if isinstance(_a, Ne):
a = ~a
else:
a, b, c = BooleanFunction.binary_check_and_simplify(
a, b, c)
rv = None
if kwargs.get('evaluate', True):
rv = cls.eval(a, b, c)
if rv is None:
rv = BooleanFunction.__new__(cls, a, b, c, evaluate=False)
return rv
@classmethod
def eval(cls, *args):
from sympy.core.relational import Eq, Ne
# do the args give a singular result?
a, b, c = args
if isinstance(a, (Ne, Eq)):
_a = a
if S.true in a.args:
a = a.lhs if a.rhs is S.true else a.rhs
elif S.false in a.args:
a = ~a.lhs if a.rhs is S.false else ~a.rhs
else:
_a = None
if _a is not None and isinstance(_a, Ne):
a = ~a
if a is S.true:
return b
if a is S.false:
return c
if b == c:
return b
else:
# or maybe the results allow the answer to be expressed
# in terms of the condition
if b is S.true and c is S.false:
return a
if b is S.false and c is S.true:
return Not(a)
if [a, b, c] != args:
return cls(a, b, c, evaluate=False)
def to_nnf(self, simplify=True):
a, b, c = self.args
return And._to_nnf(Or(~a, b), Or(a, c), simplify=simplify)
def _eval_as_set(self):
return self.to_nnf().as_set()
def _eval_rewrite_as_Piecewise(self, *args, **kwargs):
from sympy.functions import Piecewise
return Piecewise((args[1], args[0]), (args[2], True))
### end class definitions. Some useful methods
def conjuncts(expr):
"""Return a list of the conjuncts in the expr s.
Examples
========
>>> from sympy.logic.boolalg import conjuncts
>>> from sympy.abc import A, B
>>> conjuncts(A & B)
frozenset({A, B})
>>> conjuncts(A | B)
frozenset({A | B})
"""
return And.make_args(expr)
def disjuncts(expr):
"""Return a list of the disjuncts in the sentence s.
Examples
========
>>> from sympy.logic.boolalg import disjuncts
>>> from sympy.abc import A, B
>>> disjuncts(A | B)
frozenset({A, B})
>>> disjuncts(A & B)
frozenset({A & B})
"""
return Or.make_args(expr)
def distribute_and_over_or(expr):
"""
Given a sentence s consisting of conjunctions and disjunctions
of literals, return an equivalent sentence in CNF.
Examples
========
>>> from sympy.logic.boolalg import distribute_and_over_or, And, Or, Not
>>> from sympy.abc import A, B, C
>>> distribute_and_over_or(Or(A, And(Not(B), Not(C))))
(A | ~B) & (A | ~C)
"""
return _distribute((expr, And, Or))
def distribute_or_over_and(expr):
"""
Given a sentence s consisting of conjunctions and disjunctions
of literals, return an equivalent sentence in DNF.
Note that the output is NOT simplified.
Examples
========
>>> from sympy.logic.boolalg import distribute_or_over_and, And, Or, Not
>>> from sympy.abc import A, B, C
>>> distribute_or_over_and(And(Or(Not(A), B), C))
(B & C) | (C & ~A)
"""
return _distribute((expr, Or, And))
def _distribute(info):
"""
Distributes info[1] over info[2] with respect to info[0].
"""
if isinstance(info[0], info[2]):
for arg in info[0].args:
if isinstance(arg, info[1]):
conj = arg
break
else:
return info[0]
rest = info[2](*[a for a in info[0].args if a is not conj])
return info[1](*list(map(_distribute,
[(info[2](c, rest), info[1], info[2]) for c in conj.args])))
elif isinstance(info[0], info[1]):
return info[1](*list(map(_distribute,
[(x, info[1], info[2]) for x in info[0].args])))
else:
return info[0]
def to_nnf(expr, simplify=True):
"""
Converts expr to Negation Normal Form.
A logical expression is in Negation Normal Form (NNF) if it
contains only And, Or and Not, and Not is applied only to literals.
If simplify is True, the result contains no redundant clauses.
Examples
========
>>> from sympy.abc import A, B, C, D
>>> from sympy.logic.boolalg import Not, Equivalent, to_nnf
>>> to_nnf(Not((~A & ~B) | (C & D)))
(A | B) & (~C | ~D)
>>> to_nnf(Equivalent(A >> B, B >> A))
(A | ~B | (A & ~B)) & (B | ~A | (B & ~A))
"""
if is_nnf(expr, simplify):
return expr
return expr.to_nnf(simplify)
def to_cnf(expr, simplify=False):
"""
Convert a propositional logical sentence s to conjunctive normal form.
That is, of the form ((A | ~B | ...) & (B | C | ...) & ...)
If simplify is True, the expr is evaluated to its simplest CNF form.
Examples
========
>>> from sympy.logic.boolalg import to_cnf
>>> from sympy.abc import A, B, D
>>> to_cnf(~(A | B) | D)
(D | ~A) & (D | ~B)
>>> to_cnf((A | B) & (A | ~A), True)
A | B
"""
expr = sympify(expr)
if not isinstance(expr, BooleanFunction):
return expr
if simplify:
return simplify_logic(expr, 'cnf', True)
# Don't convert unless we have to
if is_cnf(expr):
return expr
expr = eliminate_implications(expr)
return distribute_and_over_or(expr)
def to_dnf(expr, simplify=False):
"""
Convert a propositional logical sentence s to disjunctive normal form.
That is, of the form ((A & ~B & ...) | (B & C & ...) | ...)
If simplify is True, the expr is evaluated to its simplest DNF form.
Examples
========
>>> from sympy.logic.boolalg import to_dnf
>>> from sympy.abc import A, B, C
>>> to_dnf(B & (A | C))
(A & B) | (B & C)
>>> to_dnf((A & B) | (A & ~B) | (B & C) | (~B & C), True)
A | C
"""
expr = sympify(expr)
if not isinstance(expr, BooleanFunction):
return expr
if simplify:
return simplify_logic(expr, 'dnf', True)
# Don't convert unless we have to
if is_dnf(expr):
return expr
expr = eliminate_implications(expr)
return distribute_or_over_and(expr)
def is_nnf(expr, simplified=True):
"""
Checks if expr is in Negation Normal Form.
A logical expression is in Negation Normal Form (NNF) if it
contains only And, Or and Not, and Not is applied only to literals.
If simpified is True, checks if result contains no redundant clauses.
Examples
========
>>> from sympy.abc import A, B, C
>>> from sympy.logic.boolalg import Not, is_nnf
>>> is_nnf(A & B | ~C)
True
>>> is_nnf((A | ~A) & (B | C))
False
>>> is_nnf((A | ~A) & (B | C), False)
True
>>> is_nnf(Not(A & B) | C)
False
>>> is_nnf((A >> B) & (B >> A))
False
"""
expr = sympify(expr)
if is_literal(expr):
return True
stack = [expr]
while stack:
expr = stack.pop()
if expr.func in (And, Or):
if simplified:
args = expr.args
for arg in args:
if Not(arg) in args:
return False
stack.extend(expr.args)
elif not is_literal(expr):
return False
return True
def is_cnf(expr):
"""
Test whether or not an expression is in conjunctive normal form.
Examples
========
>>> from sympy.logic.boolalg import is_cnf
>>> from sympy.abc import A, B, C
>>> is_cnf(A | B | C)
True
>>> is_cnf(A & B & C)
True
>>> is_cnf((A & B) | C)
False
"""
return _is_form(expr, And, Or)
def is_dnf(expr):
"""
Test whether or not an expression is in disjunctive normal form.
Examples
========
>>> from sympy.logic.boolalg import is_dnf
>>> from sympy.abc import A, B, C
>>> is_dnf(A | B | C)
True
>>> is_dnf(A & B & C)
True
>>> is_dnf((A & B) | C)
True
>>> is_dnf(A & (B | C))
False
"""
return _is_form(expr, Or, And)
def _is_form(expr, function1, function2):
"""
Test whether or not an expression is of the required form.
"""
expr = sympify(expr)
# Special case of an Atom
if expr.is_Atom:
return True
# Special case of a single expression of function2
if isinstance(expr, function2):
for lit in expr.args:
if isinstance(lit, Not):
if not lit.args[0].is_Atom:
return False
else:
if not lit.is_Atom:
return False
return True
# Special case of a single negation
if isinstance(expr, Not):
if not expr.args[0].is_Atom:
return False
if not isinstance(expr, function1):
return False
for cls in expr.args:
if cls.is_Atom:
continue
if isinstance(cls, Not):
if not cls.args[0].is_Atom:
return False
elif not isinstance(cls, function2):
return False
for lit in cls.args:
if isinstance(lit, Not):
if not lit.args[0].is_Atom:
return False
else:
if not lit.is_Atom:
return False
return True
def eliminate_implications(expr):
"""
Change >>, <<, and Equivalent into &, |, and ~. That is, return an
expression that is equivalent to s, but has only &, |, and ~ as logical
operators.
Examples
========
>>> from sympy.logic.boolalg import Implies, Equivalent, \
eliminate_implications
>>> from sympy.abc import A, B, C
>>> eliminate_implications(Implies(A, B))
B | ~A
>>> eliminate_implications(Equivalent(A, B))
(A | ~B) & (B | ~A)
>>> eliminate_implications(Equivalent(A, B, C))
(A | ~C) & (B | ~A) & (C | ~B)
"""
return to_nnf(expr, simplify=False)
def is_literal(expr):
"""
Returns True if expr is a literal, else False.
Examples
========
>>> from sympy import Or, Q
>>> from sympy.abc import A, B
>>> from sympy.logic.boolalg import is_literal
>>> is_literal(A)
True
>>> is_literal(~A)
True
>>> is_literal(Q.zero(A))
True
>>> is_literal(A + B)
True
>>> is_literal(Or(A, B))
False
"""
if isinstance(expr, Not):
return not isinstance(expr.args[0], BooleanFunction)
else:
return not isinstance(expr, BooleanFunction)
def to_int_repr(clauses, symbols):
"""
Takes clauses in CNF format and puts them into an integer representation.
Examples
========
>>> from sympy.logic.boolalg import to_int_repr
>>> from sympy.abc import x, y
>>> to_int_repr([x | y, y], [x, y]) == [{1, 2}, {2}]
True
"""
# Convert the symbol list into a dict
symbols = dict(list(zip(symbols, list(range(1, len(symbols) + 1)))))
def append_symbol(arg, symbols):
if isinstance(arg, Not):
return -symbols[arg.args[0]]
else:
return symbols[arg]
return [set(append_symbol(arg, symbols) for arg in Or.make_args(c))
for c in clauses]
def term_to_integer(term):
"""
Return an integer corresponding to the base-2 digits given by ``term``.
Parameters
==========
term : a string or list of ones and zeros
Examples
========
>>> from sympy.logic.boolalg import term_to_integer
>>> term_to_integer([1, 0, 0])
4
>>> term_to_integer('100')
4
"""
return int(''.join(list(map(str, list(term)))), 2)
def integer_to_term(k, n_bits=None):
"""
Return a list of the base-2 digits in the integer, ``k``.
Parameters
==========
k : int
n_bits : int
If ``n_bits`` is given and the number of digits in the binary
representation of ``k`` is smaller than ``n_bits`` then left-pad the
list with 0s.
Examples
========
>>> from sympy.logic.boolalg import integer_to_term
>>> integer_to_term(4)
[1, 0, 0]
>>> integer_to_term(4, 6)
[0, 0, 0, 1, 0, 0]
"""
s = '{0:0{1}b}'.format(abs(as_int(k)), as_int(abs(n_bits or 0)))
return list(map(int, s))
def truth_table(expr, variables, input=True):
"""
Return a generator of all possible configurations of the input variables,
and the result of the boolean expression for those values.
Parameters
==========
expr : string or boolean expression
variables : list of variables
input : boolean (default True)
indicates whether to return the input combinations.
Examples
========
>>> from sympy.logic.boolalg import truth_table
>>> from sympy.abc import x,y
>>> table = truth_table(x >> y, [x, y])
>>> for t in table:
... print('{0} -> {1}'.format(*t))
[0, 0] -> True
[0, 1] -> True
[1, 0] -> False
[1, 1] -> True
>>> table = truth_table(x | y, [x, y])
>>> list(table)
[([0, 0], False), ([0, 1], True), ([1, 0], True), ([1, 1], True)]
If input is false, truth_table returns only a list of truth values.
In this case, the corresponding input values of variables can be
deduced from the index of a given output.
>>> from sympy.logic.boolalg import integer_to_term
>>> vars = [y, x]
>>> values = truth_table(x >> y, vars, input=False)
>>> values = list(values)
>>> values
[True, False, True, True]
>>> for i, value in enumerate(values):
... print('{0} -> {1}'.format(list(zip(
... vars, integer_to_term(i, len(vars)))), value))
[(y, 0), (x, 0)] -> True
[(y, 0), (x, 1)] -> False
[(y, 1), (x, 0)] -> True
[(y, 1), (x, 1)] -> True
"""
variables = [sympify(v) for v in variables]
expr = sympify(expr)
if not isinstance(expr, BooleanFunction) and not is_literal(expr):
return
table = product([0, 1], repeat=len(variables))
for term in table:
term = list(term)
value = expr.xreplace(dict(zip(variables, term)))
if input:
yield term, value
else:
yield value
def _check_pair(minterm1, minterm2):
"""
Checks if a pair of minterms differs by only one bit. If yes, returns
index, else returns -1.
"""
index = -1
for x, (i, j) in enumerate(zip(minterm1, minterm2)):
if i != j:
if index == -1:
index = x
else:
return -1
return index
def _convert_to_varsSOP(minterm, variables):
"""
Converts a term in the expansion of a function from binary to its
variable form (for SOP).
"""
temp = []
for i, m in enumerate(minterm):
if m == 0:
temp.append(Not(variables[i]))
elif m == 1:
temp.append(variables[i])
else:
pass # ignore the 3s
return And(*temp)
def _convert_to_varsPOS(maxterm, variables):
"""
Converts a term in the expansion of a function from binary to its
variable form (for POS).
"""
temp = []
for i, m in enumerate(maxterm):
if m == 1:
temp.append(Not(variables[i]))
elif m == 0:
temp.append(variables[i])
else:
pass # ignore the 3s
return Or(*temp)
def _simplified_pairs(terms):
"""
Reduces a set of minterms, if possible, to a simplified set of minterms
with one less variable in the terms using QM method.
"""
simplified_terms = []
todo = list(range(len(terms)))
for i, ti in enumerate(terms[:-1]):
for j_i, tj in enumerate(terms[(i + 1):]):
index = _check_pair(ti, tj)
if index != -1:
todo[i] = todo[j_i + i + 1] = None
newterm = ti[:]
newterm[index] = 3
if newterm not in simplified_terms:
simplified_terms.append(newterm)
simplified_terms.extend(
[terms[i] for i in [_ for _ in todo if _ is not None]])
return simplified_terms
def _compare_term(minterm, term):
"""
Return True if a binary term is satisfied by the given term. Used
for recognizing prime implicants.
"""
for i, x in enumerate(term):
if x != 3 and x != minterm[i]:
return False
return True
def _rem_redundancy(l1, terms):
"""
After the truth table has been sufficiently simplified, use the prime
implicant table method to recognize and eliminate redundant pairs,
and return the essential arguments.
"""
essential = []
for x in terms:
temporary = []
for y in l1:
if _compare_term(x, y):
temporary.append(y)
if len(temporary) == 1:
if temporary[0] not in essential:
essential.append(temporary[0])
for x in terms:
for y in essential:
if _compare_term(x, y):
break
else:
for z in l1:
if _compare_term(x, z):
if z not in essential:
essential.append(z)
break
return essential
def SOPform(variables, minterms, dontcares=None):
"""
The SOPform function uses simplified_pairs and a redundant group-
eliminating algorithm to convert the list of all input combos that
generate '1' (the minterms) into the smallest Sum of Products form.
The variables must be given as the first argument.
Return a logical Or function (i.e., the "sum of products" or "SOP"
form) that gives the desired outcome. If there are inputs that can
be ignored, pass them as a list, too.
The result will be one of the (perhaps many) functions that satisfy
the conditions.
Examples
========
>>> from sympy.logic import SOPform
>>> from sympy import symbols
>>> w, x, y, z = symbols('w x y z')
>>> minterms = [[0, 0, 0, 1], [0, 0, 1, 1],
... [0, 1, 1, 1], [1, 0, 1, 1], [1, 1, 1, 1]]
>>> dontcares = [[0, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 1]]
>>> SOPform([w, x, y, z], minterms, dontcares)
(y & z) | (z & ~w)
References
==========
.. [1] en.wikipedia.org/wiki/Quine-McCluskey_algorithm
"""
variables = [sympify(v) for v in variables]
if minterms == []:
return false
minterms = [list(i) for i in minterms]
dontcares = [list(i) for i in (dontcares or [])]
for d in dontcares:
if d in minterms:
raise ValueError('%s in minterms is also in dontcares' % d)
old = None
new = minterms + dontcares
while new != old:
old = new
new = _simplified_pairs(old)
essential = _rem_redundancy(new, minterms)
return Or(*[_convert_to_varsSOP(x, variables) for x in essential])
def POSform(variables, minterms, dontcares=None):
"""
The POSform function uses simplified_pairs and a redundant-group
eliminating algorithm to convert the list of all input combinations
that generate '1' (the minterms) into the smallest Product of Sums form.
The variables must be given as the first argument.
Return a logical And function (i.e., the "product of sums" or "POS"
form) that gives the desired outcome. If there are inputs that can
be ignored, pass them as a list, too.
The result will be one of the (perhaps many) functions that satisfy
the conditions.
Examples
========
>>> from sympy.logic import POSform
>>> from sympy import symbols
>>> w, x, y, z = symbols('w x y z')
>>> minterms = [[0, 0, 0, 1], [0, 0, 1, 1], [0, 1, 1, 1],
... [1, 0, 1, 1], [1, 1, 1, 1]]
>>> dontcares = [[0, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 1]]
>>> POSform([w, x, y, z], minterms, dontcares)
z & (y | ~w)
References
==========
.. [1] en.wikipedia.org/wiki/Quine-McCluskey_algorithm
"""
variables = [sympify(v) for v in variables]
if minterms == []:
return false
minterms = [list(i) for i in minterms]
dontcares = [list(i) for i in (dontcares or [])]
for d in dontcares:
if d in minterms:
raise ValueError('%s in minterms is also in dontcares' % d)
maxterms = []
for t in product([0, 1], repeat=len(variables)):
t = list(t)
if (t not in minterms) and (t not in dontcares):
maxterms.append(t)
old = None
new = maxterms + dontcares
while new != old:
old = new
new = _simplified_pairs(old)
essential = _rem_redundancy(new, maxterms)
return And(*[_convert_to_varsPOS(x, variables) for x in essential])
def _find_predicates(expr):
"""Helper to find logical predicates in BooleanFunctions.
A logical predicate is defined here as anything within a BooleanFunction
that is not a BooleanFunction itself.
"""
if not isinstance(expr, BooleanFunction):
return {expr}
return set().union(*(_find_predicates(i) for i in expr.args))
def simplify_logic(expr, form=None, deep=True):
"""
This function simplifies a boolean function to its simplified version
in SOP or POS form. The return type is an Or or And object in SymPy.
Parameters
==========
expr : string or boolean expression
form : string ('cnf' or 'dnf') or None (default).
If 'cnf' or 'dnf', the simplest expression in the corresponding
normal form is returned; if None, the answer is returned
according to the form with fewest args (in CNF by default).
deep : boolean (default True)
indicates whether to recursively simplify any
non-boolean functions contained within the input.
Examples
========
>>> from sympy.logic import simplify_logic
>>> from sympy.abc import x, y, z
>>> from sympy import S
>>> b = (~x & ~y & ~z) | ( ~x & ~y & z)
>>> simplify_logic(b)
~x & ~y
>>> S(b)
(z & ~x & ~y) | (~x & ~y & ~z)
>>> simplify_logic(_)
~x & ~y
"""
if form not in (None, 'cnf', 'dnf'):
raise ValueError("form can be cnf or dnf only")
expr = sympify(expr)
if deep:
variables = _find_predicates(expr)
from sympy.simplify.simplify import simplify
s = [simplify(v) for v in variables]
expr = expr.xreplace(dict(zip(variables, s)))
if not isinstance(expr, BooleanFunction):
return expr
# get variables in case not deep or after doing
# deep simplification since they may have changed
variables = _find_predicates(expr)
# group into constants and variable values
c, v = sift(variables, lambda x: x in (True, False), binary=True)
variables = c + v
truthtable = []
# standardize constants to be 1 or 0 in keeping with truthtable
c = [1 if i==True else 0 for i in c]
for t in product([0, 1], repeat=len(v)):
if expr.xreplace(dict(zip(v, t))) == True:
truthtable.append(c + list(t))
big = len(truthtable) >= (2 ** (len(variables) - 1))
if form == 'dnf' or form is None and big:
return SOPform(variables, truthtable)
return POSform(variables, truthtable)
def _finger(eq):
"""
Assign a 5-item fingerprint to each symbol in the equation:
[
# of times it appeared as a Symbol,
# of times it appeared as a Not(symbol),
# of times it appeared as a Symbol in an And or Or,
# of times it appeared as a Not(Symbol) in an And or Or,
sum of the number of arguments with which it appeared
as a Symbol, counting Symbol as 1 and Not(Symbol) as 2
and counting self as 1
]
>>> from sympy.logic.boolalg import _finger as finger
>>> from sympy import And, Or, Not
>>> from sympy.abc import a, b, x, y
>>> eq = Or(And(Not(y), a), And(Not(y), b), And(x, y))
>>> dict(finger(eq))
{(0, 0, 1, 0, 2): [x], (0, 0, 1, 0, 3): [a, b], (0, 0, 1, 2, 2): [y]}
>>> dict(finger(x & ~y))
{(0, 1, 0, 0, 0): [y], (1, 0, 0, 0, 0): [x]}
The equation must not have more than one level of nesting:
>>> dict(finger(And(Or(x, y), y)))
{(0, 0, 1, 0, 2): [x], (1, 0, 1, 0, 2): [y]}
>>> dict(finger(And(Or(x, And(a, x)), y)))
Traceback (most recent call last):
...
NotImplementedError: unexpected level of nesting
So y and x have unique fingerprints, but a and b do not.
"""
f = eq.free_symbols
d = dict(list(zip(f, [[0] * 5 for fi in f])))
for a in eq.args:
if a.is_Symbol:
d[a][0] += 1
elif a.is_Not:
d[a.args[0]][1] += 1
else:
o = len(a.args) + sum(isinstance(ai, Not) for ai in a.args)
for ai in a.args:
if ai.is_Symbol:
d[ai][2] += 1
d[ai][-1] += o
elif ai.is_Not:
d[ai.args[0]][3] += 1
else:
raise NotImplementedError('unexpected level of nesting')
inv = defaultdict(list)
for k, v in ordered(iter(d.items())):
inv[tuple(v)].append(k)
return inv
def bool_map(bool1, bool2):
"""
Return the simplified version of bool1, and the mapping of variables
that makes the two expressions bool1 and bool2 represent the same
logical behaviour for some correspondence between the variables
of each.
If more than one mappings of this sort exist, one of them
is returned.
For example, And(x, y) is logically equivalent to And(a, b) for
the mapping {x: a, y:b} or {x: b, y:a}.
If no such mapping exists, return False.
Examples
========
>>> from sympy import SOPform, bool_map, Or, And, Not, Xor
>>> from sympy.abc import w, x, y, z, a, b, c, d
>>> function1 = SOPform([x, z, y],[[1, 0, 1], [0, 0, 1]])
>>> function2 = SOPform([a, b, c],[[1, 0, 1], [1, 0, 0]])
>>> bool_map(function1, function2)
(y & ~z, {y: a, z: b})
The results are not necessarily unique, but they are canonical. Here,
``(w, z)`` could be ``(a, d)`` or ``(d, a)``:
>>> eq = Or(And(Not(y), w), And(Not(y), z), And(x, y))
>>> eq2 = Or(And(Not(c), a), And(Not(c), d), And(b, c))
>>> bool_map(eq, eq2)
((x & y) | (w & ~y) | (z & ~y), {w: a, x: b, y: c, z: d})
>>> eq = And(Xor(a, b), c, And(c,d))
>>> bool_map(eq, eq.subs(c, x))
(c & d & (a | b) & (~a | ~b), {a: a, b: b, c: d, d: x})
"""
def match(function1, function2):
"""Return the mapping that equates variables between two
simplified boolean expressions if possible.
By "simplified" we mean that a function has been denested
and is either an And (or an Or) whose arguments are either
symbols (x), negated symbols (Not(x)), or Or (or an And) whose
arguments are only symbols or negated symbols. For example,
And(x, Not(y), Or(w, Not(z))).
Basic.match is not robust enough (see issue 4835) so this is
a workaround that is valid for simplified boolean expressions
"""
# do some quick checks
if function1.__class__ != function2.__class__:
return None # maybe simplification would make them the same
if len(function1.args) != len(function2.args):
return None # maybe simplification would make them the same
if function1.is_Symbol:
return {function1: function2}
# get the fingerprint dictionaries
f1 = _finger(function1)
f2 = _finger(function2)
# more quick checks
if len(f1) != len(f2):
return False
# assemble the match dictionary if possible
matchdict = {}
for k in f1.keys():
if k not in f2:
return False
if len(f1[k]) != len(f2[k]):
return False
for i, x in enumerate(f1[k]):
matchdict[x] = f2[k][i]
return matchdict
a = simplify_logic(bool1)
b = simplify_logic(bool2)
m = match(a, b)
if m:
return a, m
return m
|
41c2b9cd3a6f1337f5b6a2bfd5f3915db654b22b38b1e82146f04131d44d22e5
|
from __future__ import print_function, division
import random
from sympy import Derivative
from sympy.core import SympifyError
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.compatibility import is_sequence, as_int, range, reduce
from sympy.core.function import count_ops, expand_mul
from sympy.core.singleton import S
from sympy.core.symbol import Symbol
from sympy.core.sympify import sympify
from sympy.functions.elementary.complexes import Abs
from sympy.functions.elementary.trigonometric import cos, sin
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.simplify import simplify as _simplify
from sympy.utilities.misc import filldedent
from sympy.utilities.decorator import doctest_depends_on
from sympy.matrices.matrices import MatrixBase, ShapeError
from sympy.matrices.common import a2idx, classof
def _iszero(x):
"""Returns True if x is zero."""
return x.is_zero
def _compare_sequence(a, b):
"""Compares the elements of a list/tuple `a`
and a list/tuple `b`. `_compare_sequence((1,2), [1, 2])`
is True, whereas `(1,2) == [1, 2]` is False"""
if type(a) is type(b):
# if they are the same type, compare directly
return a == b
# there is no overhead for calling `tuple` on a
# tuple
return tuple(a) == tuple(b)
class DenseMatrix(MatrixBase):
is_MatrixExpr = False
_op_priority = 10.01
_class_priority = 4
def __eq__(self, other):
try:
other = sympify(other)
if self.shape != other.shape:
return False
if isinstance(other, Matrix):
return _compare_sequence(self._mat, other._mat)
elif isinstance(other, MatrixBase):
return _compare_sequence(self._mat, Matrix(other)._mat)
except AttributeError:
return False
def __getitem__(self, key):
"""Return portion of self defined by key. If the key involves a slice
then a list will be returned (if key is a single slice) or a matrix
(if key was a tuple involving a slice).
Examples
========
>>> from sympy import Matrix, I
>>> m = Matrix([
... [1, 2 + I],
... [3, 4 ]])
If the key is a tuple that doesn't involve a slice then that element
is returned:
>>> m[1, 0]
3
When a tuple key involves a slice, a matrix is returned. Here, the
first column is selected (all rows, column 0):
>>> m[:, 0]
Matrix([
[1],
[3]])
If the slice is not a tuple then it selects from the underlying
list of elements that are arranged in row order and a list is
returned if a slice is involved:
>>> m[0]
1
>>> m[::2]
[1, 3]
"""
if isinstance(key, tuple):
i, j = key
try:
i, j = self.key2ij(key)
return self._mat[i*self.cols + j]
except (TypeError, IndexError):
if (isinstance(i, Expr) and not i.is_number) or (isinstance(j, Expr) and not j.is_number):
if ((j < 0) is True) or ((j >= self.shape[1]) is True) or\
((i < 0) is True) or ((i >= self.shape[0]) is True):
raise ValueError("index out of boundary")
from sympy.matrices.expressions.matexpr import MatrixElement
return MatrixElement(self, i, j)
if isinstance(i, slice):
# XXX remove list() when PY2 support is dropped
i = list(range(self.rows))[i]
elif is_sequence(i):
pass
else:
i = [i]
if isinstance(j, slice):
# XXX remove list() when PY2 support is dropped
j = list(range(self.cols))[j]
elif is_sequence(j):
pass
else:
j = [j]
return self.extract(i, j)
else:
# row-wise decomposition of matrix
if isinstance(key, slice):
return self._mat[key]
return self._mat[a2idx(key)]
def __setitem__(self, key, value):
raise NotImplementedError()
def _cholesky(self, hermitian=True):
"""Helper function of cholesky.
Without the error checks.
To be used privately.
Implements the Cholesky-Banachiewicz algorithm.
Returns L such that L*L.H == self if hermitian flag is True,
or L*L.T == self if hermitian is False.
"""
L = zeros(self.rows, self.rows)
if hermitian:
for i in range(self.rows):
for j in range(i):
L[i, j] = (1 / L[j, j])*expand_mul(self[i, j] -
sum(L[i, k]*L[j, k].conjugate() for k in range(j)))
Lii2 = expand_mul(self[i, i] -
sum(L[i, k]*L[i, k].conjugate() for k in range(i)))
if Lii2.is_positive is False:
raise ValueError("Matrix must be positive-definite")
L[i, i] = sqrt(Lii2)
else:
for i in range(self.rows):
for j in range(i):
L[i, j] = (1 / L[j, j])*(self[i, j] -
sum(L[i, k]*L[j, k] for k in range(j)))
L[i, i] = sqrt(self[i, i] -
sum(L[i, k]**2 for k in range(i)))
return self._new(L)
def _diagonal_solve(self, rhs):
"""Helper function of function diagonal_solve,
without the error checks, to be used privately.
"""
return self._new(rhs.rows, rhs.cols, lambda i, j: rhs[i, j] / self[i, i])
def _eval_add(self, other):
# we assume both arguments are dense matrices since
# sparse matrices have a higher priority
mat = [a + b for a,b in zip(self._mat, other._mat)]
return classof(self, other)._new(self.rows, self.cols, mat, copy=False)
def _eval_extract(self, rowsList, colsList):
mat = self._mat
cols = self.cols
indices = (i * cols + j for i in rowsList for j in colsList)
return self._new(len(rowsList), len(colsList),
list(mat[i] for i in indices), copy=False)
def _eval_matrix_mul(self, other):
from sympy import Add
# cache attributes for faster access
self_rows, self_cols = self.rows, self.cols
other_rows, other_cols = other.rows, other.cols
other_len = other_rows * other_cols
new_mat_rows = self.rows
new_mat_cols = other.cols
# preallocate the array
new_mat = [S.Zero]*new_mat_rows*new_mat_cols
# if we multiply an n x 0 with a 0 x m, the
# expected behavior is to produce an n x m matrix of zeros
if self.cols != 0 and other.rows != 0:
# cache self._mat and other._mat for performance
mat = self._mat
other_mat = other._mat
for i in range(len(new_mat)):
row, col = i // new_mat_cols, i % new_mat_cols
row_indices = range(self_cols*row, self_cols*(row+1))
col_indices = range(col, other_len, other_cols)
vec = (mat[a]*other_mat[b] for a,b in zip(row_indices, col_indices))
try:
new_mat[i] = Add(*vec)
except (TypeError, SympifyError):
# Block matrices don't work with `sum` or `Add` (ISSUE #11599)
# They don't work with `sum` because `sum` tries to add `0`
# initially, and for a matrix, that is a mix of a scalar and
# a matrix, which raises a TypeError. Fall back to a
# block-matrix-safe way to multiply if the `sum` fails.
vec = (mat[a]*other_mat[b] for a,b in zip(row_indices, col_indices))
new_mat[i] = reduce(lambda a,b: a + b, vec)
return classof(self, other)._new(new_mat_rows, new_mat_cols, new_mat, copy=False)
def _eval_matrix_mul_elementwise(self, other):
mat = [a*b for a,b in zip(self._mat, other._mat)]
return classof(self, other)._new(self.rows, self.cols, mat, copy=False)
def _eval_inverse(self, **kwargs):
"""Return the matrix inverse using the method indicated (default
is Gauss elimination).
kwargs
======
method : ('GE', 'LU', or 'ADJ')
iszerofunc
try_block_diag
Notes
=====
According to the ``method`` keyword, it calls the appropriate method:
GE .... inverse_GE(); default
LU .... inverse_LU()
ADJ ... inverse_ADJ()
According to the ``try_block_diag`` keyword, it will try to form block
diagonal matrices using the method get_diag_blocks(), invert these
individually, and then reconstruct the full inverse matrix.
Note, the GE and LU methods may require the matrix to be simplified
before it is inverted in order to properly detect zeros during
pivoting. In difficult cases a custom zero detection function can
be provided by setting the ``iszerosfunc`` argument to a function that
should return True if its argument is zero. The ADJ routine computes
the determinant and uses that to detect singular matrices in addition
to testing for zeros on the diagonal.
See Also
========
inverse_LU
inverse_GE
inverse_ADJ
"""
from sympy.matrices import diag
method = kwargs.get('method', 'GE')
iszerofunc = kwargs.get('iszerofunc', _iszero)
if kwargs.get('try_block_diag', False):
blocks = self.get_diag_blocks()
r = []
for block in blocks:
r.append(block.inv(method=method, iszerofunc=iszerofunc))
return diag(*r)
M = self.as_mutable()
if method == "GE":
rv = M.inverse_GE(iszerofunc=iszerofunc)
elif method == "LU":
rv = M.inverse_LU(iszerofunc=iszerofunc)
elif method == "ADJ":
rv = M.inverse_ADJ(iszerofunc=iszerofunc)
else:
# make sure to add an invertibility check (as in inverse_LU)
# if a new method is added.
raise ValueError("Inversion method unrecognized")
return self._new(rv)
def _eval_scalar_mul(self, other):
mat = [other*a for a in self._mat]
return self._new(self.rows, self.cols, mat, copy=False)
def _eval_scalar_rmul(self, other):
mat = [a*other for a in self._mat]
return self._new(self.rows, self.cols, mat, copy=False)
def _eval_tolist(self):
mat = list(self._mat)
cols = self.cols
return [mat[i*cols:(i + 1)*cols] for i in range(self.rows)]
def _LDLdecomposition(self, hermitian=True):
"""Helper function of LDLdecomposition.
Without the error checks.
To be used privately.
Returns L and D such that L*D*L.H == self if hermitian flag is True,
or L*D*L.T == self if hermitian is False.
"""
# https://en.wikipedia.org/wiki/Cholesky_decomposition#LDL_decomposition_2
D = zeros(self.rows, self.rows)
L = eye(self.rows)
if hermitian:
for i in range(self.rows):
for j in range(i):
L[i, j] = (1 / D[j, j])*expand_mul(self[i, j] - sum(
L[i, k]*L[j, k].conjugate()*D[k, k] for k in range(j)))
D[i, i] = expand_mul(self[i, i] -
sum(L[i, k]*L[i, k].conjugate()*D[k, k] for k in range(i)))
if D[i, i].is_positive is False:
raise ValueError("Matrix must be positive-definite")
else:
for i in range(self.rows):
for j in range(i):
L[i, j] = (1 / D[j, j])*(self[i, j] - sum(
L[i, k]*L[j, k]*D[k, k] for k in range(j)))
D[i, i] = self[i, i] - sum(L[i, k]**2*D[k, k] for k in range(i))
return self._new(L), self._new(D)
def _lower_triangular_solve(self, rhs):
"""Helper function of function lower_triangular_solve.
Without the error checks.
To be used privately.
"""
X = zeros(self.rows, rhs.cols)
for j in range(rhs.cols):
for i in range(self.rows):
if self[i, i] == 0:
raise TypeError("Matrix must be non-singular.")
X[i, j] = (rhs[i, j] - sum(self[i, k]*X[k, j]
for k in range(i))) / self[i, i]
return self._new(X)
def _upper_triangular_solve(self, rhs):
"""Helper function of function upper_triangular_solve.
Without the error checks, to be used privately. """
X = zeros(self.rows, rhs.cols)
for j in range(rhs.cols):
for i in reversed(range(self.rows)):
if self[i, i] == 0:
raise ValueError("Matrix must be non-singular.")
X[i, j] = (rhs[i, j] - sum(self[i, k]*X[k, j]
for k in range(i + 1, self.rows))) / self[i, i]
return self._new(X)
def as_immutable(self):
"""Returns an Immutable version of this Matrix
"""
from .immutable import ImmutableDenseMatrix as cls
if self.rows and self.cols:
return cls._new(self.tolist())
return cls._new(self.rows, self.cols, [])
def as_mutable(self):
"""Returns a mutable version of this matrix
Examples
========
>>> from sympy import ImmutableMatrix
>>> X = ImmutableMatrix([[1, 2], [3, 4]])
>>> Y = X.as_mutable()
>>> Y[1, 1] = 5 # Can set values in Y
>>> Y
Matrix([
[1, 2],
[3, 5]])
"""
return Matrix(self)
def equals(self, other, failing_expression=False):
"""Applies ``equals`` to corresponding elements of the matrices,
trying to prove that the elements are equivalent, returning True
if they are, False if any pair is not, and None (or the first
failing expression if failing_expression is True) if it cannot
be decided if the expressions are equivalent or not. This is, in
general, an expensive operation.
Examples
========
>>> from sympy.matrices import Matrix
>>> from sympy.abc import x
>>> from sympy import cos
>>> A = Matrix([x*(x - 1), 0])
>>> B = Matrix([x**2 - x, 0])
>>> A == B
False
>>> A.simplify() == B.simplify()
True
>>> A.equals(B)
True
>>> A.equals(2)
False
See Also
========
sympy.core.expr.equals
"""
try:
if self.shape != other.shape:
return False
rv = True
for i in range(self.rows):
for j in range(self.cols):
ans = self[i, j].equals(other[i, j], failing_expression)
if ans is False:
return False
elif ans is not True and rv is True:
rv = ans
return rv
except AttributeError:
return False
def _force_mutable(x):
"""Return a matrix as a Matrix, otherwise return x."""
if getattr(x, 'is_Matrix', False):
return x.as_mutable()
elif isinstance(x, Basic):
return x
elif hasattr(x, '__array__'):
a = x.__array__()
if len(a.shape) == 0:
return sympify(a)
return Matrix(x)
return x
class MutableDenseMatrix(DenseMatrix, MatrixBase):
def __new__(cls, *args, **kwargs):
return cls._new(*args, **kwargs)
@classmethod
def _new(cls, *args, **kwargs):
# if the `copy` flag is set to False, the input
# was rows, cols, [list]. It should be used directly
# without creating a copy.
if kwargs.get('copy', True) is False:
if len(args) != 3:
raise TypeError("'copy=False' requires a matrix be initialized as rows,cols,[list]")
rows, cols, flat_list = args
else:
rows, cols, flat_list = cls._handle_creation_inputs(*args, **kwargs)
flat_list = list(flat_list) # create a shallow copy
self = object.__new__(cls)
self.rows = rows
self.cols = cols
self._mat = flat_list
return self
def __setitem__(self, key, value):
"""
Examples
========
>>> from sympy import Matrix, I, zeros, ones
>>> m = Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m[1, 0] = 9
>>> m
Matrix([
[1, 2 + I],
[9, 4]])
>>> m[1, 0] = [[0, 1]]
To replace row r you assign to position r*m where m
is the number of columns:
>>> M = zeros(4)
>>> m = M.cols
>>> M[3*m] = ones(1, m)*2; M
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0],
[2, 2, 2, 2]])
And to replace column c you can assign to position c:
>>> M[2] = ones(m, 1)*4; M
Matrix([
[0, 0, 4, 0],
[0, 0, 4, 0],
[0, 0, 4, 0],
[2, 2, 4, 2]])
"""
rv = self._setitem(key, value)
if rv is not None:
i, j, value = rv
self._mat[i*self.cols + j] = value
def as_mutable(self):
return self.copy()
def col_del(self, i):
"""Delete the given column.
Examples
========
>>> from sympy.matrices import eye
>>> M = eye(3)
>>> M.col_del(1)
>>> M
Matrix([
[1, 0],
[0, 0],
[0, 1]])
See Also
========
col
row_del
"""
if i < -self.cols or i >= self.cols:
raise IndexError("Index out of range: 'i=%s', valid -%s <= i < %s"
% (i, self.cols, self.cols))
for j in range(self.rows - 1, -1, -1):
del self._mat[i + j*self.cols]
self.cols -= 1
def col_op(self, j, f):
"""In-place operation on col j using two-arg functor whose args are
interpreted as (self[i, j], i).
Examples
========
>>> from sympy.matrices import eye
>>> M = eye(3)
>>> M.col_op(1, lambda v, i: v + 2*M[i, 0]); M
Matrix([
[1, 2, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
col
row_op
"""
self._mat[j::self.cols] = [f(*t) for t in list(zip(self._mat[j::self.cols], list(range(self.rows))))]
def col_swap(self, i, j):
"""Swap the two given columns of the matrix in-place.
Examples
========
>>> from sympy.matrices import Matrix
>>> M = Matrix([[1, 0], [1, 0]])
>>> M
Matrix([
[1, 0],
[1, 0]])
>>> M.col_swap(0, 1)
>>> M
Matrix([
[0, 1],
[0, 1]])
See Also
========
col
row_swap
"""
for k in range(0, self.rows):
self[k, i], self[k, j] = self[k, j], self[k, i]
def copyin_list(self, key, value):
"""Copy in elements from a list.
Parameters
==========
key : slice
The section of this matrix to replace.
value : iterable
The iterable to copy values from.
Examples
========
>>> from sympy.matrices import eye
>>> I = eye(3)
>>> I[:2, 0] = [1, 2] # col
>>> I
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
>>> I[1, :2] = [[3, 4]]
>>> I
Matrix([
[1, 0, 0],
[3, 4, 0],
[0, 0, 1]])
See Also
========
copyin_matrix
"""
if not is_sequence(value):
raise TypeError("`value` must be an ordered iterable, not %s." % type(value))
return self.copyin_matrix(key, Matrix(value))
def copyin_matrix(self, key, value):
"""Copy in values from a matrix into the given bounds.
Parameters
==========
key : slice
The section of this matrix to replace.
value : Matrix
The matrix to copy values from.
Examples
========
>>> from sympy.matrices import Matrix, eye
>>> M = Matrix([[0, 1], [2, 3], [4, 5]])
>>> I = eye(3)
>>> I[:3, :2] = M
>>> I
Matrix([
[0, 1, 0],
[2, 3, 0],
[4, 5, 1]])
>>> I[0, 1] = M
>>> I
Matrix([
[0, 0, 1],
[2, 2, 3],
[4, 4, 5]])
See Also
========
copyin_list
"""
rlo, rhi, clo, chi = self.key2bounds(key)
shape = value.shape
dr, dc = rhi - rlo, chi - clo
if shape != (dr, dc):
raise ShapeError(filldedent("The Matrix `value` doesn't have the "
"same dimensions "
"as the in sub-Matrix given by `key`."))
for i in range(value.rows):
for j in range(value.cols):
self[i + rlo, j + clo] = value[i, j]
def fill(self, value):
"""Fill the matrix with the scalar value.
See Also
========
zeros
ones
"""
self._mat = [value]*len(self)
def row_del(self, i):
"""Delete the given row.
Examples
========
>>> from sympy.matrices import eye
>>> M = eye(3)
>>> M.row_del(1)
>>> M
Matrix([
[1, 0, 0],
[0, 0, 1]])
See Also
========
row
col_del
"""
if i < -self.rows or i >= self.rows:
raise IndexError("Index out of range: 'i = %s', valid -%s <= i"
" < %s" % (i, self.rows, self.rows))
if i < 0:
i += self.rows
del self._mat[i*self.cols:(i+1)*self.cols]
self.rows -= 1
def row_op(self, i, f):
"""In-place operation on row ``i`` using two-arg functor whose args are
interpreted as ``(self[i, j], j)``.
Examples
========
>>> from sympy.matrices import eye
>>> M = eye(3)
>>> M.row_op(1, lambda v, j: v + 2*M[0, j]); M
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
See Also
========
row
zip_row_op
col_op
"""
i0 = i*self.cols
ri = self._mat[i0: i0 + self.cols]
self._mat[i0: i0 + self.cols] = [f(x, j) for x, j in zip(ri, list(range(self.cols)))]
def row_swap(self, i, j):
"""Swap the two given rows of the matrix in-place.
Examples
========
>>> from sympy.matrices import Matrix
>>> M = Matrix([[0, 1], [1, 0]])
>>> M
Matrix([
[0, 1],
[1, 0]])
>>> M.row_swap(0, 1)
>>> M
Matrix([
[1, 0],
[0, 1]])
See Also
========
row
col_swap
"""
for k in range(0, self.cols):
self[i, k], self[j, k] = self[j, k], self[i, k]
def simplify(self, ratio=1.7, measure=count_ops, rational=False, inverse=False):
"""Applies simplify to the elements of a matrix in place.
This is a shortcut for M.applyfunc(lambda x: simplify(x, ratio, measure))
See Also
========
sympy.simplify.simplify.simplify
"""
for i in range(len(self._mat)):
self._mat[i] = _simplify(self._mat[i], ratio=ratio, measure=measure,
rational=rational, inverse=inverse)
def zip_row_op(self, i, k, f):
"""In-place operation on row ``i`` using two-arg functor whose args are
interpreted as ``(self[i, j], self[k, j])``.
Examples
========
>>> from sympy.matrices import eye
>>> M = eye(3)
>>> M.zip_row_op(1, 0, lambda v, u: v + 2*u); M
Matrix([
[1, 0, 0],
[2, 1, 0],
[0, 0, 1]])
See Also
========
row
row_op
col_op
"""
i0 = i*self.cols
k0 = k*self.cols
ri = self._mat[i0: i0 + self.cols]
rk = self._mat[k0: k0 + self.cols]
self._mat[i0: i0 + self.cols] = [f(x, y) for x, y in zip(ri, rk)]
# Utility functions
MutableMatrix = Matrix = MutableDenseMatrix
###########
# Numpy Utility Functions:
# list2numpy, matrix2numpy, symmarray, rot_axis[123]
###########
def list2numpy(l, dtype=object): # pragma: no cover
"""Converts python list of SymPy expressions to a NumPy array.
See Also
========
matrix2numpy
"""
from numpy import empty
a = empty(len(l), dtype)
for i, s in enumerate(l):
a[i] = s
return a
def matrix2numpy(m, dtype=object): # pragma: no cover
"""Converts SymPy's matrix to a NumPy array.
See Also
========
list2numpy
"""
from numpy import empty
a = empty(m.shape, dtype)
for i in range(m.rows):
for j in range(m.cols):
a[i, j] = m[i, j]
return a
def rot_axis3(theta):
"""Returns a rotation matrix for a rotation of theta (in radians) about
the 3-axis.
Examples
========
>>> from sympy import pi
>>> from sympy.matrices import rot_axis3
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis3(theta)
Matrix([
[ 1/2, sqrt(3)/2, 0],
[-sqrt(3)/2, 1/2, 0],
[ 0, 0, 1]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis3(pi/2)
Matrix([
[ 0, 1, 0],
[-1, 0, 0],
[ 0, 0, 1]])
See Also
========
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis
"""
ct = cos(theta)
st = sin(theta)
lil = ((ct, st, 0),
(-st, ct, 0),
(0, 0, 1))
return Matrix(lil)
def rot_axis2(theta):
"""Returns a rotation matrix for a rotation of theta (in radians) about
the 2-axis.
Examples
========
>>> from sympy import pi
>>> from sympy.matrices import rot_axis2
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis2(theta)
Matrix([
[ 1/2, 0, -sqrt(3)/2],
[ 0, 1, 0],
[sqrt(3)/2, 0, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis2(pi/2)
Matrix([
[0, 0, -1],
[0, 1, 0],
[1, 0, 0]])
See Also
========
rot_axis1: Returns a rotation matrix for a rotation of theta (in radians)
about the 1-axis
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis
"""
ct = cos(theta)
st = sin(theta)
lil = ((ct, 0, -st),
(0, 1, 0),
(st, 0, ct))
return Matrix(lil)
def rot_axis1(theta):
"""Returns a rotation matrix for a rotation of theta (in radians) about
the 1-axis.
Examples
========
>>> from sympy import pi
>>> from sympy.matrices import rot_axis1
A rotation of pi/3 (60 degrees):
>>> theta = pi/3
>>> rot_axis1(theta)
Matrix([
[1, 0, 0],
[0, 1/2, sqrt(3)/2],
[0, -sqrt(3)/2, 1/2]])
If we rotate by pi/2 (90 degrees):
>>> rot_axis1(pi/2)
Matrix([
[1, 0, 0],
[0, 0, 1],
[0, -1, 0]])
See Also
========
rot_axis2: Returns a rotation matrix for a rotation of theta (in radians)
about the 2-axis
rot_axis3: Returns a rotation matrix for a rotation of theta (in radians)
about the 3-axis
"""
ct = cos(theta)
st = sin(theta)
lil = ((1, 0, 0),
(0, ct, st),
(0, -st, ct))
return Matrix(lil)
@doctest_depends_on(modules=('numpy',))
def symarray(prefix, shape, **kwargs): # pragma: no cover
r"""Create a numpy ndarray of symbols (as an object array).
The created symbols are named ``prefix_i1_i2_``... You should thus provide a
non-empty prefix if you want your symbols to be unique for different output
arrays, as SymPy symbols with identical names are the same object.
Parameters
----------
prefix : string
A prefix prepended to the name of every symbol.
shape : int or tuple
Shape of the created array. If an int, the array is one-dimensional; for
more than one dimension the shape must be a tuple.
\*\*kwargs : dict
keyword arguments passed on to Symbol
Examples
========
These doctests require numpy.
>>> from sympy import symarray
>>> symarray('', 3)
[_0 _1 _2]
If you want multiple symarrays to contain distinct symbols, you *must*
provide unique prefixes:
>>> a = symarray('', 3)
>>> b = symarray('', 3)
>>> a[0] == b[0]
True
>>> a = symarray('a', 3)
>>> b = symarray('b', 3)
>>> a[0] == b[0]
False
Creating symarrays with a prefix:
>>> symarray('a', 3)
[a_0 a_1 a_2]
For more than one dimension, the shape must be given as a tuple:
>>> symarray('a', (2, 3))
[[a_0_0 a_0_1 a_0_2]
[a_1_0 a_1_1 a_1_2]]
>>> symarray('a', (2, 3, 2))
[[[a_0_0_0 a_0_0_1]
[a_0_1_0 a_0_1_1]
[a_0_2_0 a_0_2_1]]
<BLANKLINE>
[[a_1_0_0 a_1_0_1]
[a_1_1_0 a_1_1_1]
[a_1_2_0 a_1_2_1]]]
For setting assumptions of the underlying Symbols:
>>> [s.is_real for s in symarray('a', 2, real=True)]
[True, True]
"""
from numpy import empty, ndindex
arr = empty(shape, dtype=object)
for index in ndindex(shape):
arr[index] = Symbol('%s_%s' % (prefix, '_'.join(map(str, index))),
**kwargs)
return arr
###############
# Functions
###############
def casoratian(seqs, n, zero=True):
"""Given linear difference operator L of order 'k' and homogeneous
equation Ly = 0 we want to compute kernel of L, which is a set
of 'k' sequences: a(n), b(n), ... z(n).
Solutions of L are linearly independent iff their Casoratian,
denoted as C(a, b, ..., z), do not vanish for n = 0.
Casoratian is defined by k x k determinant::
+ a(n) b(n) . . . z(n) +
| a(n+1) b(n+1) . . . z(n+1) |
| . . . . |
| . . . . |
| . . . . |
+ a(n+k-1) b(n+k-1) . . . z(n+k-1) +
It proves very useful in rsolve_hyper() where it is applied
to a generating set of a recurrence to factor out linearly
dependent solutions and return a basis:
>>> from sympy import Symbol, casoratian, factorial
>>> n = Symbol('n', integer=True)
Exponential and factorial are linearly independent:
>>> casoratian([2**n, factorial(n)], n) != 0
True
"""
from .dense import Matrix
seqs = list(map(sympify, seqs))
if not zero:
f = lambda i, j: seqs[j].subs(n, n + i)
else:
f = lambda i, j: seqs[j].subs(n, i)
k = len(seqs)
return Matrix(k, k, f).det()
def eye(*args, **kwargs):
"""Create square identity matrix n x n
See Also
========
diag
zeros
ones
"""
from .dense import Matrix
return Matrix.eye(*args, **kwargs)
def diag(*values, **kwargs):
"""Create a sparse, diagonal matrix from a list of diagonal values.
Notes
=====
When arguments are matrices they are fitted in resultant matrix.
The returned matrix is a mutable, dense matrix. To make it a different
type, send the desired class for keyword ``cls``.
Examples
========
>>> from sympy.matrices import diag, Matrix, ones
>>> diag(1, 2, 3)
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> diag(*[1, 2, 3])
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
The diagonal elements can be matrices; diagonal filling will
continue on the diagonal from the last element of the matrix:
>>> from sympy.abc import x, y, z
>>> a = Matrix([x, y, z])
>>> b = Matrix([[1, 2], [3, 4]])
>>> c = Matrix([[5, 6]])
>>> diag(a, 7, b, c)
Matrix([
[x, 0, 0, 0, 0, 0],
[y, 0, 0, 0, 0, 0],
[z, 0, 0, 0, 0, 0],
[0, 7, 0, 0, 0, 0],
[0, 0, 1, 2, 0, 0],
[0, 0, 3, 4, 0, 0],
[0, 0, 0, 0, 5, 6]])
When diagonal elements are lists, they will be treated as arguments
to Matrix:
>>> diag([1, 2, 3], 4)
Matrix([
[1, 0],
[2, 0],
[3, 0],
[0, 4]])
>>> diag([[1, 2, 3]], 4)
Matrix([
[1, 2, 3, 0],
[0, 0, 0, 4]])
A given band off the diagonal can be made by padding with a
vertical or horizontal "kerning" vector:
>>> hpad = ones(0, 2)
>>> vpad = ones(2, 0)
>>> diag(vpad, 1, 2, 3, hpad) + diag(hpad, 4, 5, 6, vpad)
Matrix([
[0, 0, 4, 0, 0],
[0, 0, 0, 5, 0],
[1, 0, 0, 0, 6],
[0, 2, 0, 0, 0],
[0, 0, 3, 0, 0]])
The type is mutable by default but can be made immutable by setting
the ``mutable`` flag to False:
>>> type(diag(1))
<class 'sympy.matrices.dense.MutableDenseMatrix'>
>>> from sympy.matrices import ImmutableMatrix
>>> type(diag(1, cls=ImmutableMatrix))
<class 'sympy.matrices.immutable.ImmutableDenseMatrix'>
See Also
========
eye
"""
from .dense import Matrix
# diag assumes any lists passed in are to be interpreted
# as arguments to Matrix, so apply Matrix to any list arguments
def normalize(m):
if is_sequence(m) and not isinstance(m, MatrixBase):
return Matrix(m)
return m
values = (normalize(m) for m in values)
return Matrix.diag(*values, **kwargs)
def GramSchmidt(vlist, orthonormal=False):
"""
Apply the Gram-Schmidt process to a set of vectors.
see: https://en.wikipedia.org/wiki/Gram%E2%80%93Schmidt_process
"""
out = []
m = len(vlist)
for i in range(m):
tmp = vlist[i]
for j in range(i):
tmp -= vlist[i].project(out[j])
if not tmp.values():
raise ValueError(
"GramSchmidt: vector set not linearly independent")
out.append(tmp)
if orthonormal:
for i in range(len(out)):
out[i] = out[i].normalized()
return out
def hessian(f, varlist, constraints=[]):
"""Compute Hessian matrix for a function f wrt parameters in varlist
which may be given as a sequence or a row/column vector. A list of
constraints may optionally be given.
Examples
========
>>> from sympy import Function, hessian, pprint
>>> from sympy.abc import x, y
>>> f = Function('f')(x, y)
>>> g1 = Function('g')(x, y)
>>> g2 = x**2 + 3*y
>>> pprint(hessian(f, (x, y), [g1, g2]))
[ d d ]
[ 0 0 --(g(x, y)) --(g(x, y)) ]
[ dx dy ]
[ ]
[ 0 0 2*x 3 ]
[ ]
[ 2 2 ]
[d d d ]
[--(g(x, y)) 2*x ---(f(x, y)) -----(f(x, y))]
[dx 2 dy dx ]
[ dx ]
[ ]
[ 2 2 ]
[d d d ]
[--(g(x, y)) 3 -----(f(x, y)) ---(f(x, y)) ]
[dy dy dx 2 ]
[ dy ]
References
==========
https://en.wikipedia.org/wiki/Hessian_matrix
See Also
========
sympy.matrices.mutable.Matrix.jacobian
wronskian
"""
# f is the expression representing a function f, return regular matrix
if isinstance(varlist, MatrixBase):
if 1 not in varlist.shape:
raise ShapeError("`varlist` must be a column or row vector.")
if varlist.cols == 1:
varlist = varlist.T
varlist = varlist.tolist()[0]
if is_sequence(varlist):
n = len(varlist)
if not n:
raise ShapeError("`len(varlist)` must not be zero.")
else:
raise ValueError("Improper variable list in hessian function")
if not getattr(f, 'diff'):
# check differentiability
raise ValueError("Function `f` (%s) is not differentiable" % f)
m = len(constraints)
N = m + n
out = zeros(N)
for k, g in enumerate(constraints):
if not getattr(g, 'diff'):
# check differentiability
raise ValueError("Function `f` (%s) is not differentiable" % f)
for i in range(n):
out[k, i + m] = g.diff(varlist[i])
for i in range(n):
for j in range(i, n):
out[i + m, j + m] = f.diff(varlist[i]).diff(varlist[j])
for i in range(N):
for j in range(i + 1, N):
out[j, i] = out[i, j]
return out
def jordan_cell(eigenval, n):
"""
Create a Jordan block:
Examples
========
>>> from sympy.matrices import jordan_cell
>>> from sympy.abc import x
>>> jordan_cell(x, 4)
Matrix([
[x, 1, 0, 0],
[0, x, 1, 0],
[0, 0, x, 1],
[0, 0, 0, x]])
"""
from .dense import Matrix
return Matrix.jordan_block(size=n, eigenvalue=eigenval)
def matrix_multiply_elementwise(A, B):
"""Return the Hadamard product (elementwise product) of A and B
>>> from sympy.matrices import matrix_multiply_elementwise
>>> from sympy.matrices import Matrix
>>> A = Matrix([[0, 1, 2], [3, 4, 5]])
>>> B = Matrix([[1, 10, 100], [100, 10, 1]])
>>> matrix_multiply_elementwise(A, B)
Matrix([
[ 0, 10, 200],
[300, 40, 5]])
See Also
========
__mul__
"""
return A.multiply_elementwise(B)
def ones(*args, **kwargs):
"""Returns a matrix of ones with ``rows`` rows and ``cols`` columns;
if ``cols`` is omitted a square matrix will be returned.
See Also
========
zeros
eye
diag
"""
if 'c' in kwargs:
kwargs['cols'] = kwargs.pop('c')
from .dense import Matrix
return Matrix.ones(*args, **kwargs)
def randMatrix(r, c=None, min=0, max=99, seed=None, symmetric=False,
percent=100, prng=None):
"""Create random matrix with dimensions ``r`` x ``c``. If ``c`` is omitted
the matrix will be square. If ``symmetric`` is True the matrix must be
square. If ``percent`` is less than 100 then only approximately the given
percentage of elements will be non-zero.
The pseudo-random number generator used to generate matrix is chosen in the
following way.
* If ``prng`` is supplied, it will be used as random number generator.
It should be an instance of :class:`random.Random`, or at least have
``randint`` and ``shuffle`` methods with same signatures.
* if ``prng`` is not supplied but ``seed`` is supplied, then new
:class:`random.Random` with given ``seed`` will be created;
* otherwise, a new :class:`random.Random` with default seed will be used.
Examples
========
>>> from sympy.matrices import randMatrix
>>> randMatrix(3) # doctest:+SKIP
[25, 45, 27]
[44, 54, 9]
[23, 96, 46]
>>> randMatrix(3, 2) # doctest:+SKIP
[87, 29]
[23, 37]
[90, 26]
>>> randMatrix(3, 3, 0, 2) # doctest:+SKIP
[0, 2, 0]
[2, 0, 1]
[0, 0, 1]
>>> randMatrix(3, symmetric=True) # doctest:+SKIP
[85, 26, 29]
[26, 71, 43]
[29, 43, 57]
>>> A = randMatrix(3, seed=1)
>>> B = randMatrix(3, seed=2)
>>> A == B # doctest:+SKIP
False
>>> A == randMatrix(3, seed=1)
True
>>> randMatrix(3, symmetric=True, percent=50) # doctest:+SKIP
[77, 70, 0],
[70, 0, 0],
[ 0, 0, 88]
"""
if c is None:
c = r
# Note that ``Random()`` is equivalent to ``Random(None)``
prng = prng or random.Random(seed)
if not symmetric:
m = Matrix._new(r, c, lambda i, j: prng.randint(min, max))
if percent == 100:
return m
z = int(r*c*(100 - percent) // 100)
m._mat[:z] = [S.Zero]*z
prng.shuffle(m._mat)
return m
# Symmetric case
if r != c:
raise ValueError('For symmetric matrices, r must equal c, but %i != %i' % (r, c))
m = zeros(r)
ij = [(i, j) for i in range(r) for j in range(i, r)]
if percent != 100:
ij = prng.sample(ij, int(len(ij)*percent // 100))
for i, j in ij:
value = prng.randint(min, max)
m[i, j] = m[j, i] = value
return m
def wronskian(functions, var, method='bareiss'):
"""
Compute Wronskian for [] of functions
::
| f1 f2 ... fn |
| f1' f2' ... fn' |
| . . . . |
W(f1, ..., fn) = | . . . . |
| . . . . |
| (n) (n) (n) |
| D (f1) D (f2) ... D (fn) |
see: https://en.wikipedia.org/wiki/Wronskian
See Also
========
sympy.matrices.mutable.Matrix.jacobian
hessian
"""
from .dense import Matrix
for index in range(0, len(functions)):
functions[index] = sympify(functions[index])
n = len(functions)
if n == 0:
return 1
W = Matrix(n, n, lambda i, j: functions[i].diff(var, j))
return W.det(method)
def zeros(*args, **kwargs):
"""Returns a matrix of zeros with ``rows`` rows and ``cols`` columns;
if ``cols`` is omitted a square matrix will be returned.
See Also
========
ones
eye
diag
"""
if 'c' in kwargs:
kwargs['cols'] = kwargs.pop('c')
from .dense import Matrix
return Matrix.zeros(*args, **kwargs)
|
8aef85bbfff3a2bead07cecbcc26432647fd5a5aa2c0e722adf946d381034d1d
|
from __future__ import print_function, division
from mpmath.libmp.libmpf import prec_to_dps
from sympy.core.add import Add
from sympy.core.basic import Basic
from sympy.core.expr import Expr
from sympy.core.function import expand_mul
from sympy.core.power import Pow
from sympy.core.symbol import (Symbol, Dummy, symbols,
_uniquely_named_symbol)
from sympy.core.numbers import Integer, mod_inverse, Float
from sympy.core.singleton import S
from sympy.core.sympify import sympify
from sympy.functions.elementary.miscellaneous import sqrt, Max, Min
from sympy.functions import exp, factorial
from sympy.polys import PurePoly, roots, cancel
from sympy.printing import sstr
from sympy.simplify import simplify as _simplify, nsimplify
from sympy.core.compatibility import reduce, as_int, string_types, Callable
from sympy.utilities.iterables import flatten, numbered_symbols
from sympy.core.compatibility import (is_sequence, default_sort_key, range,
NotIterable)
from sympy.utilities.exceptions import SymPyDeprecationWarning
from types import FunctionType
from .common import (a2idx, MatrixError, ShapeError,
NonSquareMatrixError, MatrixCommon)
from sympy.core.decorators import deprecated
def _iszero(x):
"""Returns True if x is zero."""
try:
return x.is_zero
except AttributeError:
return None
def _is_zero_after_expand_mul(x):
"""Tests by expand_mul only, suitable for polynomials and rational
functions."""
return expand_mul(x) == 0
class DeferredVector(Symbol, NotIterable):
"""A vector whose components are deferred (e.g. for use with lambdify)
Examples
========
>>> from sympy import DeferredVector, lambdify
>>> X = DeferredVector( 'X' )
>>> X
X
>>> expr = (X[0] + 2, X[2] + 3)
>>> func = lambdify( X, expr)
>>> func( [1, 2, 3] )
(3, 6)
"""
def __getitem__(self, i):
if i == -0:
i = 0
if i < 0:
raise IndexError('DeferredVector index out of range')
component_name = '%s[%d]' % (self.name, i)
return Symbol(component_name)
def __str__(self):
return sstr(self)
def __repr__(self):
return "DeferredVector('%s')" % self.name
class MatrixDeterminant(MatrixCommon):
"""Provides basic matrix determinant operations.
Should not be instantiated directly."""
def _eval_berkowitz_toeplitz_matrix(self):
"""Return (A,T) where T the Toeplitz matrix used in the Berkowitz algorithm
corresponding to `self` and A is the first principal submatrix."""
# the 0 x 0 case is trivial
if self.rows == 0 and self.cols == 0:
return self._new(1,1, [S.One])
#
# Partition self = [ a_11 R ]
# [ C A ]
#
a, R = self[0,0], self[0, 1:]
C, A = self[1:, 0], self[1:,1:]
#
# The Toeplitz matrix looks like
#
# [ 1 ]
# [ -a 1 ]
# [ -RC -a 1 ]
# [ -RAC -RC -a 1 ]
# [ -RA**2C -RAC -RC -a 1 ]
# etc.
# Compute the diagonal entries.
# Because multiplying matrix times vector is so much
# more efficient than matrix times matrix, recursively
# compute -R * A**n * C.
diags = [C]
for i in range(self.rows - 2):
diags.append(A * diags[i])
diags = [(-R*d)[0, 0] for d in diags]
diags = [S.One, -a] + diags
def entry(i,j):
if j > i:
return S.Zero
return diags[i - j]
toeplitz = self._new(self.cols + 1, self.rows, entry)
return (A, toeplitz)
def _eval_berkowitz_vector(self):
""" Run the Berkowitz algorithm and return a vector whose entries
are the coefficients of the characteristic polynomial of `self`.
Given N x N matrix, efficiently compute
coefficients of characteristic polynomials of 'self'
without division in the ground domain.
This method is particularly useful for computing determinant,
principal minors and characteristic polynomial when 'self'
has complicated coefficients e.g. polynomials. Semi-direct
usage of this algorithm is also important in computing
efficiently sub-resultant PRS.
Assuming that M is a square matrix of dimension N x N and
I is N x N identity matrix, then the Berkowitz vector is
an N x 1 vector whose entries are coefficients of the
polynomial
charpoly(M) = det(t*I - M)
As a consequence, all polynomials generated by Berkowitz
algorithm are monic.
For more information on the implemented algorithm refer to:
[1] S.J. Berkowitz, On computing the determinant in small
parallel time using a small number of processors, ACM,
Information Processing Letters 18, 1984, pp. 147-150
[2] M. Keber, Division-Free computation of sub-resultants
using Bezout matrices, Tech. Report MPI-I-2006-1-006,
Saarbrucken, 2006
"""
# handle the trivial cases
if self.rows == 0 and self.cols == 0:
return self._new(1, 1, [S.One])
elif self.rows == 1 and self.cols == 1:
return self._new(2, 1, [S.One, -self[0,0]])
submat, toeplitz = self._eval_berkowitz_toeplitz_matrix()
return toeplitz * submat._eval_berkowitz_vector()
def _eval_det_bareiss(self, iszerofunc=_is_zero_after_expand_mul):
"""Compute matrix determinant using Bareiss' fraction-free
algorithm which is an extension of the well known Gaussian
elimination method. This approach is best suited for dense
symbolic matrices and will result in a determinant with
minimal number of fractions. It means that less term
rewriting is needed on resulting formulae.
TODO: Implement algorithm for sparse matrices (SFF),
http://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps.
"""
# Recursively implemented Bareiss' algorithm as per Deanna Richelle Leggett's
# thesis http://www.math.usm.edu/perry/Research/Thesis_DRL.pdf
def bareiss(mat, cumm=1):
if mat.rows == 0:
return S.One
elif mat.rows == 1:
return mat[0, 0]
# find a pivot and extract the remaining matrix
# With the default iszerofunc, _find_reasonable_pivot slows down
# the computation by the factor of 2.5 in one test.
# Relevant issues: #10279 and #13877.
pivot_pos, pivot_val, _, _ = _find_reasonable_pivot(mat[:, 0],
iszerofunc=iszerofunc)
if pivot_pos == None:
return S.Zero
# if we have a valid pivot, we'll do a "row swap", so keep the
# sign of the det
sign = (-1) ** (pivot_pos % 2)
# we want every row but the pivot row and every column
rows = list(i for i in range(mat.rows) if i != pivot_pos)
cols = list(range(mat.cols))
tmp_mat = mat.extract(rows, cols)
def entry(i, j):
ret = (pivot_val*tmp_mat[i, j + 1] - mat[pivot_pos, j + 1]*tmp_mat[i, 0]) / cumm
if not ret.is_Atom:
return cancel(ret)
return ret
return sign*bareiss(self._new(mat.rows - 1, mat.cols - 1, entry), pivot_val)
return cancel(bareiss(self))
def _eval_det_berkowitz(self):
""" Use the Berkowitz algorithm to compute the determinant."""
berk_vector = self._eval_berkowitz_vector()
return (-1)**(len(berk_vector) - 1) * berk_vector[-1]
def _eval_det_lu(self, iszerofunc=_iszero, simpfunc=None):
""" Computes the determinant of a matrix from its LU decomposition.
This function uses the LU decomposition computed by
LUDecomposition_Simple().
The keyword arguments iszerofunc and simpfunc are passed to
LUDecomposition_Simple().
iszerofunc is a callable that returns a boolean indicating if its
input is zero, or None if it cannot make the determination.
simpfunc is a callable that simplifies its input.
The default is simpfunc=None, which indicate that the pivot search
algorithm should not attempt to simplify any candidate pivots.
If simpfunc fails to simplify its input, then it must return its input
instead of a copy."""
if self.rows == 0:
return S.One
# sympy/matrices/tests/test_matrices.py contains a test that
# suggests that the determinant of a 0 x 0 matrix is one, by
# convention.
lu, row_swaps = self.LUdecomposition_Simple(iszerofunc=iszerofunc, simpfunc=None)
# P*A = L*U => det(A) = det(L)*det(U)/det(P) = det(P)*det(U).
# Lower triangular factor L encoded in lu has unit diagonal => det(L) = 1.
# P is a permutation matrix => det(P) in {-1, 1} => 1/det(P) = det(P).
# LUdecomposition_Simple() returns a list of row exchange index pairs, rather
# than a permutation matrix, but det(P) = (-1)**len(row_swaps).
# Avoid forming the potentially time consuming product of U's diagonal entries
# if the product is zero.
# Bottom right entry of U is 0 => det(A) = 0.
# It may be impossible to determine if this entry of U is zero when it is symbolic.
if iszerofunc(lu[lu.rows-1, lu.rows-1]):
return S.Zero
# Compute det(P)
det = -S.One if len(row_swaps)%2 else S.One
# Compute det(U) by calculating the product of U's diagonal entries.
# The upper triangular portion of lu is the upper triangular portion of the
# U factor in the LU decomposition.
for k in range(lu.rows):
det *= lu[k, k]
# return det(P)*det(U)
return det
def _eval_determinant(self):
"""Assumed to exist by matrix expressions; If we subclass
MatrixDeterminant, we can fully evaluate determinants."""
return self.det()
def adjugate(self, method="berkowitz"):
"""Returns the adjugate, or classical adjoint, of
a matrix. That is, the transpose of the matrix of cofactors.
https://en.wikipedia.org/wiki/Adjugate
See Also
========
cofactor_matrix
transpose
"""
return self.cofactor_matrix(method).transpose()
def charpoly(self, x='lambda', simplify=_simplify):
"""Computes characteristic polynomial det(x*I - self) where I is
the identity matrix.
A PurePoly is returned, so using different variables for ``x`` does
not affect the comparison or the polynomials:
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x, y
>>> A = Matrix([[1, 3], [2, 0]])
>>> A.charpoly(x) == A.charpoly(y)
True
Specifying ``x`` is optional; a symbol named ``lambda`` is used by
default (which looks good when pretty-printed in unicode):
>>> A.charpoly().as_expr()
lambda**2 - lambda - 6
And if ``x`` clashes with an existing symbol, underscores will
be preppended to the name to make it unique:
>>> A = Matrix([[1, 2], [x, 0]])
>>> A.charpoly(x).as_expr()
_x**2 - _x - 2*x
Whether you pass a symbol or not, the generator can be obtained
with the gen attribute since it may not be the same as the symbol
that was passed:
>>> A.charpoly(x).gen
_x
>>> A.charpoly(x).gen == x
False
Notes
=====
The Samuelson-Berkowitz algorithm is used to compute
the characteristic polynomial efficiently and without any
division operations. Thus the characteristic polynomial over any
commutative ring without zero divisors can be computed.
See Also
========
det
"""
if self.rows != self.cols:
raise NonSquareMatrixError()
berk_vector = self._eval_berkowitz_vector()
x = _uniquely_named_symbol(x, berk_vector)
return PurePoly([simplify(a) for a in berk_vector], x)
def cofactor(self, i, j, method="berkowitz"):
"""Calculate the cofactor of an element.
See Also
========
cofactor_matrix
minor
minor_submatrix
"""
if self.rows != self.cols or self.rows < 1:
raise NonSquareMatrixError()
return (-1)**((i + j) % 2) * self.minor(i, j, method)
def cofactor_matrix(self, method="berkowitz"):
"""Return a matrix containing the cofactor of each element.
See Also
========
cofactor
minor
minor_submatrix
adjugate
"""
if self.rows != self.cols or self.rows < 1:
raise NonSquareMatrixError()
return self._new(self.rows, self.cols,
lambda i, j: self.cofactor(i, j, method))
def det(self, method="bareiss", iszerofunc=None):
"""Computes the determinant of a matrix.
Parameters
==========
method : string, optional
Specifies the algorithm used for computing the matrix determinant.
If the matrix is at most 3x3, a hard-coded formula is used and the
specified method is ignored. Otherwise, it defaults to
``'bareiss'``.
If it is set to ``'bareiss'``, Bareiss' fraction-free algorithm will
be used.
If it is set to ``'berkowitz'``, Berkowitz' algorithm will be used.
Otherwise, if it is set to ``'lu'``, LU decomposition will be used.
.. note::
For backward compatibility, legacy keys like "bareis" and
"det_lu" can still be used to indicate the corresponding
methods.
And the keys are also case-insensitive for now. However, it is
suggested to use the precise keys for specifying the method.
iszerofunc : FunctionType or None, optional
If it is set to ``None``, it will be defaulted to ``_iszero`` if the
method is set to ``'bareiss'``, and ``_is_zero_after_expand_mul`` if
the method is set to ``'lu'``.
It can also accept any user-specified zero testing function, if it
is formatted as a function which accepts a single symbolic argument
and returns ``True`` if it is tested as zero and ``False`` if it
tested as non-zero, and also ``None`` if it is undecidable.
Returns
=======
det : Basic
Result of determinant.
Raises
======
ValueError
If unrecognized keys are given for ``method`` or ``iszerofunc``.
NonSquareMatrixError
If attempted to calculate determinant from a non-square matrix.
"""
# sanitize `method`
method = method.lower()
if method == "bareis":
method = "bareiss"
if method == "det_lu":
method = "lu"
if method not in ("bareiss", "berkowitz", "lu"):
raise ValueError("Determinant method '%s' unrecognized" % method)
if iszerofunc is None:
if method == "bareiss":
iszerofunc = _is_zero_after_expand_mul
elif method == "lu":
iszerofunc = _iszero
elif not isinstance(iszerofunc, FunctionType):
raise ValueError("Zero testing method '%s' unrecognized" % iszerofunc)
# if methods were made internal and all determinant calculations
# passed through here, then these lines could be factored out of
# the method routines
if self.rows != self.cols:
raise NonSquareMatrixError()
n = self.rows
if n == 0:
return S.One
elif n == 1:
return self[0,0]
elif n == 2:
return self[0, 0] * self[1, 1] - self[0, 1] * self[1, 0]
elif n == 3:
return (self[0, 0] * self[1, 1] * self[2, 2]
+ self[0, 1] * self[1, 2] * self[2, 0]
+ self[0, 2] * self[1, 0] * self[2, 1]
- self[0, 2] * self[1, 1] * self[2, 0]
- self[0, 0] * self[1, 2] * self[2, 1]
- self[0, 1] * self[1, 0] * self[2, 2])
if method == "bareiss":
return self._eval_det_bareiss(iszerofunc=iszerofunc)
elif method == "berkowitz":
return self._eval_det_berkowitz()
elif method == "lu":
return self._eval_det_lu(iszerofunc=iszerofunc)
def minor(self, i, j, method="berkowitz"):
"""Return the (i,j) minor of `self`. That is,
return the determinant of the matrix obtained by deleting
the `i`th row and `j`th column from `self`.
See Also
========
minor_submatrix
cofactor
det
"""
if self.rows != self.cols or self.rows < 1:
raise NonSquareMatrixError()
return self.minor_submatrix(i, j).det(method=method)
def minor_submatrix(self, i, j):
"""Return the submatrix obtained by removing the `i`th row
and `j`th column from `self`.
See Also
========
minor
cofactor
"""
if i < 0:
i += self.rows
if j < 0:
j += self.cols
if not 0 <= i < self.rows or not 0 <= j < self.cols:
raise ValueError("`i` and `j` must satisfy 0 <= i < `self.rows` "
"(%d)" % self.rows + "and 0 <= j < `self.cols` (%d)." % self.cols)
rows = [a for a in range(self.rows) if a != i]
cols = [a for a in range(self.cols) if a != j]
return self.extract(rows, cols)
class MatrixReductions(MatrixDeterminant):
"""Provides basic matrix row/column operations.
Should not be instantiated directly."""
def _eval_col_op_swap(self, col1, col2):
def entry(i, j):
if j == col1:
return self[i, col2]
elif j == col2:
return self[i, col1]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_multiply_col_by_const(self, col, k):
def entry(i, j):
if j == col:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_col_op_add_multiple_to_other_col(self, col, k, col2):
def entry(i, j):
if j == col:
return self[i, j] + k * self[i, col2]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_swap(self, row1, row2):
def entry(i, j):
if i == row1:
return self[row2, j]
elif i == row2:
return self[row1, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_multiply_row_by_const(self, row, k):
def entry(i, j):
if i == row:
return k * self[i, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_row_op_add_multiple_to_other_row(self, row, k, row2):
def entry(i, j):
if i == row:
return self[i, j] + k * self[row2, j]
return self[i, j]
return self._new(self.rows, self.cols, entry)
def _eval_echelon_form(self, iszerofunc, simpfunc):
"""Returns (mat, swaps) where `mat` is a row-equivalent matrix
in echelon form and `swaps` is a list of row-swaps performed."""
reduced, pivot_cols, swaps = self._row_reduce(iszerofunc, simpfunc,
normalize_last=True,
normalize=False,
zero_above=False)
return reduced, pivot_cols, swaps
def _eval_is_echelon(self, iszerofunc):
if self.rows <= 0 or self.cols <= 0:
return True
zeros_below = all(iszerofunc(t) for t in self[1:, 0])
if iszerofunc(self[0, 0]):
return zeros_below and self[:, 1:]._eval_is_echelon(iszerofunc)
return zeros_below and self[1:, 1:]._eval_is_echelon(iszerofunc)
def _eval_rref(self, iszerofunc, simpfunc, normalize_last=True):
reduced, pivot_cols, swaps = self._row_reduce(iszerofunc, simpfunc,
normalize_last, normalize=True,
zero_above=True)
return reduced, pivot_cols
def _normalize_op_args(self, op, col, k, col1, col2, error_str="col"):
"""Validate the arguments for a row/column operation. `error_str`
can be one of "row" or "col" depending on the arguments being parsed."""
if op not in ["n->kn", "n<->m", "n->n+km"]:
raise ValueError("Unknown {} operation '{}'. Valid col operations "
"are 'n->kn', 'n<->m', 'n->n+km'".format(error_str, op))
# normalize and validate the arguments
if op == "n->kn":
col = col if col is not None else col1
if col is None or k is None:
raise ValueError("For a {0} operation 'n->kn' you must provide the "
"kwargs `{0}` and `k`".format(error_str))
if not 0 <= col <= self.cols:
raise ValueError("This matrix doesn't have a {} '{}'".format(error_str, col))
if op == "n<->m":
# we need two cols to swap. It doesn't matter
# how they were specified, so gather them together and
# remove `None`
cols = set((col, k, col1, col2)).difference([None])
if len(cols) > 2:
# maybe the user left `k` by mistake?
cols = set((col, col1, col2)).difference([None])
if len(cols) != 2:
raise ValueError("For a {0} operation 'n<->m' you must provide the "
"kwargs `{0}1` and `{0}2`".format(error_str))
col1, col2 = cols
if not 0 <= col1 <= self.cols:
raise ValueError("This matrix doesn't have a {} '{}'".format(error_str, col1))
if not 0 <= col2 <= self.cols:
raise ValueError("This matrix doesn't have a {} '{}'".format(error_str, col2))
if op == "n->n+km":
col = col1 if col is None else col
col2 = col1 if col2 is None else col2
if col is None or col2 is None or k is None:
raise ValueError("For a {0} operation 'n->n+km' you must provide the "
"kwargs `{0}`, `k`, and `{0}2`".format(error_str))
if col == col2:
raise ValueError("For a {0} operation 'n->n+km' `{0}` and `{0}2` must "
"be different.".format(error_str))
if not 0 <= col <= self.cols:
raise ValueError("This matrix doesn't have a {} '{}'".format(error_str, col))
if not 0 <= col2 <= self.cols:
raise ValueError("This matrix doesn't have a {} '{}'".format(error_str, col2))
return op, col, k, col1, col2
def _permute_complexity_right(self, iszerofunc):
"""Permute columns with complicated elements as
far right as they can go. Since the `sympy` row reduction
algorithms start on the left, having complexity right-shifted
speeds things up.
Returns a tuple (mat, perm) where perm is a permutation
of the columns to perform to shift the complex columns right, and mat
is the permuted matrix."""
def complexity(i):
# the complexity of a column will be judged by how many
# element's zero-ness cannot be determined
return sum(1 if iszerofunc(e) is None else 0 for e in self[:, i])
complex = [(complexity(i), i) for i in range(self.cols)]
perm = [j for (i, j) in sorted(complex)]
return (self.permute(perm, orientation='cols'), perm)
def _row_reduce(self, iszerofunc, simpfunc, normalize_last=True,
normalize=True, zero_above=True):
"""Row reduce `self` and return a tuple (rref_matrix,
pivot_cols, swaps) where pivot_cols are the pivot columns
and swaps are any row swaps that were used in the process
of row reduction.
Parameters
==========
iszerofunc : determines if an entry can be used as a pivot
simpfunc : used to simplify elements and test if they are
zero if `iszerofunc` returns `None`
normalize_last : indicates where all row reduction should
happen in a fraction-free manner and then the rows are
normalized (so that the pivots are 1), or whether
rows should be normalized along the way (like the naive
row reduction algorithm)
normalize : whether pivot rows should be normalized so that
the pivot value is 1
zero_above : whether entries above the pivot should be zeroed.
If `zero_above=False`, an echelon matrix will be returned.
"""
rows, cols = self.rows, self.cols
mat = list(self)
def get_col(i):
return mat[i::cols]
def row_swap(i, j):
mat[i*cols:(i + 1)*cols], mat[j*cols:(j + 1)*cols] = \
mat[j*cols:(j + 1)*cols], mat[i*cols:(i + 1)*cols]
def cross_cancel(a, i, b, j):
"""Does the row op row[i] = a*row[i] - b*row[j]"""
q = (j - i)*cols
for p in range(i*cols, (i + 1)*cols):
mat[p] = a*mat[p] - b*mat[p + q]
piv_row, piv_col = 0, 0
pivot_cols = []
swaps = []
# use a fraction free method to zero above and below each pivot
while piv_col < cols and piv_row < rows:
pivot_offset, pivot_val, \
assumed_nonzero, newly_determined = _find_reasonable_pivot(
get_col(piv_col)[piv_row:], iszerofunc, simpfunc)
# _find_reasonable_pivot may have simplified some things
# in the process. Let's not let them go to waste
for (offset, val) in newly_determined:
offset += piv_row
mat[offset*cols + piv_col] = val
if pivot_offset is None:
piv_col += 1
continue
pivot_cols.append(piv_col)
if pivot_offset != 0:
row_swap(piv_row, pivot_offset + piv_row)
swaps.append((piv_row, pivot_offset + piv_row))
# if we aren't normalizing last, we normalize
# before we zero the other rows
if normalize_last is False:
i, j = piv_row, piv_col
mat[i*cols + j] = S.One
for p in range(i*cols + j + 1, (i + 1)*cols):
mat[p] = mat[p] / pivot_val
# after normalizing, the pivot value is 1
pivot_val = S.One
# zero above and below the pivot
for row in range(rows):
# don't zero our current row
if row == piv_row:
continue
# don't zero above the pivot unless we're told.
if zero_above is False and row < piv_row:
continue
# if we're already a zero, don't do anything
val = mat[row*cols + piv_col]
if iszerofunc(val):
continue
cross_cancel(pivot_val, row, val, piv_row)
piv_row += 1
# normalize each row
if normalize_last is True and normalize is True:
for piv_i, piv_j in enumerate(pivot_cols):
pivot_val = mat[piv_i*cols + piv_j]
mat[piv_i*cols + piv_j] = S.One
for p in range(piv_i*cols + piv_j + 1, (piv_i + 1)*cols):
mat[p] = mat[p] / pivot_val
return self._new(self.rows, self.cols, mat), tuple(pivot_cols), tuple(swaps)
def echelon_form(self, iszerofunc=_iszero, simplify=False, with_pivots=False):
"""Returns a matrix row-equivalent to `self` that is
in echelon form. Note that echelon form of a matrix
is *not* unique, however, properties like the row
space and the null space are preserved."""
simpfunc = simplify if isinstance(
simplify, FunctionType) else _simplify
mat, pivots, swaps = self._eval_echelon_form(iszerofunc, simpfunc)
if with_pivots:
return mat, pivots
return mat
def elementary_col_op(self, op="n->kn", col=None, k=None, col1=None, col2=None):
"""Performs the elementary column operation `op`.
`op` may be one of
* "n->kn" (column n goes to k*n)
* "n<->m" (swap column n and column m)
* "n->n+km" (column n goes to column n + k*column m)
Parameters
==========
op : string; the elementary row operation
col : the column to apply the column operation
k : the multiple to apply in the column operation
col1 : one column of a column swap
col2 : second column of a column swap or column "m" in the column operation
"n->n+km"
"""
op, col, k, col1, col2 = self._normalize_op_args(op, col, k, col1, col2, "col")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_col_op_multiply_col_by_const(col, k)
if op == "n<->m":
return self._eval_col_op_swap(col1, col2)
if op == "n->n+km":
return self._eval_col_op_add_multiple_to_other_col(col, k, col2)
def elementary_row_op(self, op="n->kn", row=None, k=None, row1=None, row2=None):
"""Performs the elementary row operation `op`.
`op` may be one of
* "n->kn" (row n goes to k*n)
* "n<->m" (swap row n and row m)
* "n->n+km" (row n goes to row n + k*row m)
Parameters
==========
op : string; the elementary row operation
row : the row to apply the row operation
k : the multiple to apply in the row operation
row1 : one row of a row swap
row2 : second row of a row swap or row "m" in the row operation
"n->n+km"
"""
op, row, k, row1, row2 = self._normalize_op_args(op, row, k, row1, row2, "row")
# now that we've validated, we're all good to dispatch
if op == "n->kn":
return self._eval_row_op_multiply_row_by_const(row, k)
if op == "n<->m":
return self._eval_row_op_swap(row1, row2)
if op == "n->n+km":
return self._eval_row_op_add_multiple_to_other_row(row, k, row2)
@property
def is_echelon(self, iszerofunc=_iszero):
"""Returns `True` if the matrix is in echelon form.
That is, all rows of zeros are at the bottom, and below
each leading non-zero in a row are exclusively zeros."""
return self._eval_is_echelon(iszerofunc)
def rank(self, iszerofunc=_iszero, simplify=False):
"""
Returns the rank of a matrix
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> m = Matrix([[1, 2], [x, 1 - 1/x]])
>>> m.rank()
2
>>> n = Matrix(3, 3, range(1, 10))
>>> n.rank()
2
"""
simpfunc = simplify if isinstance(
simplify, FunctionType) else _simplify
# for small matrices, we compute the rank explicitly
# if is_zero on elements doesn't answer the question
# for small matrices, we fall back to the full routine.
if self.rows <= 0 or self.cols <= 0:
return 0
if self.rows <= 1 or self.cols <= 1:
zeros = [iszerofunc(x) for x in self]
if False in zeros:
return 1
if self.rows == 2 and self.cols == 2:
zeros = [iszerofunc(x) for x in self]
if not False in zeros and not None in zeros:
return 0
det = self.det()
if iszerofunc(det) and False in zeros:
return 1
if iszerofunc(det) is False:
return 2
mat, _ = self._permute_complexity_right(iszerofunc=iszerofunc)
echelon_form, pivots, swaps = mat._eval_echelon_form(iszerofunc=iszerofunc, simpfunc=simpfunc)
return len(pivots)
def rref(self, iszerofunc=_iszero, simplify=False, pivots=True, normalize_last=True):
"""Return reduced row-echelon form of matrix and indices of pivot vars.
Parameters
==========
iszerofunc : Function
A function used for detecting whether an element can
act as a pivot. ``lambda x: x.is_zero`` is used by default.
simplify : Function
A function used to simplify elements when looking for a pivot.
By default SymPy's ``simplify`` is used.
pivots : True or False
If ``True``, a tuple containing the row-reduced matrix and a tuple
of pivot columns is returned. If ``False`` just the row-reduced
matrix is returned.
normalize_last : True or False
If ``True``, no pivots are normalized to `1` until after all
entries above and below each pivot are zeroed. This means the row
reduction algorithm is fraction free until the very last step.
If ``False``, the naive row reduction procedure is used where
each pivot is normalized to be `1` before row operations are
used to zero above and below the pivot.
Notes
=====
The default value of ``normalize_last=True`` can provide significant
speedup to row reduction, especially on matrices with symbols. However,
if you depend on the form row reduction algorithm leaves entries
of the matrix, set ``noramlize_last=False``
Examples
========
>>> from sympy import Matrix
>>> from sympy.abc import x
>>> m = Matrix([[1, 2], [x, 1 - 1/x]])
>>> m.rref()
(Matrix([
[1, 0],
[0, 1]]), (0, 1))
>>> rref_matrix, rref_pivots = m.rref()
>>> rref_matrix
Matrix([
[1, 0],
[0, 1]])
>>> rref_pivots
(0, 1)
"""
simpfunc = simplify if isinstance(
simplify, FunctionType) else _simplify
ret, pivot_cols = self._eval_rref(iszerofunc=iszerofunc,
simpfunc=simpfunc,
normalize_last=normalize_last)
if pivots:
ret = (ret, pivot_cols)
return ret
class MatrixSubspaces(MatrixReductions):
"""Provides methods relating to the fundamental subspaces
of a matrix. Should not be instantiated directly."""
def columnspace(self, simplify=False):
"""Returns a list of vectors (Matrix objects) that span columnspace of self
Examples
========
>>> from sympy.matrices import Matrix
>>> m = Matrix(3, 3, [1, 3, 0, -2, -6, 0, 3, 9, 6])
>>> m
Matrix([
[ 1, 3, 0],
[-2, -6, 0],
[ 3, 9, 6]])
>>> m.columnspace()
[Matrix([
[ 1],
[-2],
[ 3]]), Matrix([
[0],
[0],
[6]])]
See Also
========
nullspace
rowspace
"""
reduced, pivots = self.echelon_form(simplify=simplify, with_pivots=True)
return [self.col(i) for i in pivots]
def nullspace(self, simplify=False, iszerofunc=_iszero):
"""Returns list of vectors (Matrix objects) that span nullspace of self
Examples
========
>>> from sympy.matrices import Matrix
>>> m = Matrix(3, 3, [1, 3, 0, -2, -6, 0, 3, 9, 6])
>>> m
Matrix([
[ 1, 3, 0],
[-2, -6, 0],
[ 3, 9, 6]])
>>> m.nullspace()
[Matrix([
[-3],
[ 1],
[ 0]])]
See Also
========
columnspace
rowspace
"""
reduced, pivots = self.rref(iszerofunc=iszerofunc, simplify=simplify)
free_vars = [i for i in range(self.cols) if i not in pivots]
basis = []
for free_var in free_vars:
# for each free variable, we will set it to 1 and all others
# to 0. Then, we will use back substitution to solve the system
vec = [S.Zero]*self.cols
vec[free_var] = S.One
for piv_row, piv_col in enumerate(pivots):
vec[piv_col] -= reduced[piv_row, free_var]
basis.append(vec)
return [self._new(self.cols, 1, b) for b in basis]
def rowspace(self, simplify=False):
"""Returns a list of vectors that span the row space of self."""
reduced, pivots = self.echelon_form(simplify=simplify, with_pivots=True)
return [reduced.row(i) for i in range(len(pivots))]
@classmethod
def orthogonalize(cls, *vecs, **kwargs):
"""Apply the Gram-Schmidt orthogonalization procedure
to vectors supplied in `vecs`.
Parameters
==========
vecs
vectors to be made orthogonal
normalize : bool
If true, return an orthonormal basis.
"""
normalize = kwargs.get('normalize', False)
def project(a, b):
return b * (a.dot(b) / b.dot(b))
def perp_to_subspace(vec, basis):
"""projects vec onto the subspace given
by the orthogonal basis `basis`"""
components = [project(vec, b) for b in basis]
if len(basis) == 0:
return vec
return vec - reduce(lambda a, b: a + b, components)
ret = []
# make sure we start with a non-zero vector
while len(vecs) > 0 and vecs[0].is_zero:
del vecs[0]
for vec in vecs:
perp = perp_to_subspace(vec, ret)
if not perp.is_zero:
ret.append(perp)
if normalize:
ret = [vec / vec.norm() for vec in ret]
return ret
class MatrixEigen(MatrixSubspaces):
"""Provides basic matrix eigenvalue/vector operations.
Should not be instantiated directly."""
_cache_is_diagonalizable = None
_cache_eigenvects = None
def diagonalize(self, reals_only=False, sort=False, normalize=False):
"""
Return (P, D), where D is diagonal and
D = P^-1 * M * P
where M is current matrix.
Parameters
==========
reals_only : bool. Whether to throw an error if complex numbers are need
to diagonalize. (Default: False)
sort : bool. Sort the eigenvalues along the diagonal. (Default: False)
normalize : bool. If True, normalize the columns of P. (Default: False)
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(3, 3, [1, 2, 0, 0, 3, 0, 2, -4, 2])
>>> m
Matrix([
[1, 2, 0],
[0, 3, 0],
[2, -4, 2]])
>>> (P, D) = m.diagonalize()
>>> D
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
>>> P
Matrix([
[-1, 0, -1],
[ 0, 0, -1],
[ 2, 1, 2]])
>>> P.inv() * m * P
Matrix([
[1, 0, 0],
[0, 2, 0],
[0, 0, 3]])
See Also
========
is_diagonal
is_diagonalizable
"""
if not self.is_square:
raise NonSquareMatrixError()
if not self.is_diagonalizable(reals_only=reals_only, clear_cache=False):
raise MatrixError("Matrix is not diagonalizable")
eigenvecs = self._cache_eigenvects
if eigenvecs is None:
eigenvecs = self.eigenvects(simplify=True)
if sort:
eigenvecs = sorted(eigenvecs, key=default_sort_key)
p_cols, diag = [], []
for val, mult, basis in eigenvecs:
diag += [val] * mult
p_cols += basis
if normalize:
p_cols = [v / v.norm() for v in p_cols]
return self.hstack(*p_cols), self.diag(*diag)
def eigenvals(self, error_when_incomplete=True, **flags):
r"""Return eigenvalues using the Berkowitz agorithm to compute
the characteristic polynomial.
Parameters
==========
error_when_incomplete : bool, optional
If it is set to ``True``, it will raise an error if not all
eigenvalues are computed. This is caused by ``roots`` not returning
a full list of eigenvalues.
simplify : bool or function, optional
If it is set to ``True``, it attempts to return the most
simplified form of expressions returned by applying default
simplification method in every routine.
If it is set to ``False``, it will skip simplification in this
particular routine to save computation resources.
If a function is passed to, it will attempt to apply
the particular function as simplification method.
rational : bool, optional
If it is set to ``True``, every floating point numbers would be
replaced with rationals before computation. It can solve some
issues of ``roots`` routine not working well with floats.
multiple : bool, optional
If it is set to ``True``, the result will be in the form of a
list.
If it is set to ``False``, the result will be in the form of a
dictionary.
Returns
=======
eigs : list or dict
Eigenvalues of a matrix. The return format would be specified by
the key ``multiple``.
Raises
======
MatrixError
If not enough roots had got computed.
NonSquareMatrixError
If attempted to compute eigenvalues from a non-square matrix.
See Also
========
MatrixDeterminant.charpoly
eigenvects
Notes
=====
Eigenvalues of a matrix `A` can be computed by solving a matrix
equation `\det(A - \lambda I) = 0`
"""
simplify = flags.get('simplify', False) # Collect simplify flag before popped up, to reuse later in the routine.
multiple = flags.get('multiple', False) # Collect multiple flag to decide whether return as a dict or list.
mat = self
if not mat:
return {}
if flags.pop('rational', True):
if any(v.has(Float) for v in mat):
mat = mat.applyfunc(lambda x: nsimplify(x, rational=True))
if mat.is_upper or mat.is_lower:
if not self.is_square:
raise NonSquareMatrixError()
diagonal_entries = [mat[i, i] for i in range(mat.rows)]
if multiple:
eigs = diagonal_entries
else:
eigs = {}
for diagonal_entry in diagonal_entries:
if diagonal_entry not in eigs:
eigs[diagonal_entry] = 0
eigs[diagonal_entry] += 1
else:
flags.pop('simplify', None) # pop unsupported flag
if isinstance(simplify, FunctionType):
eigs = roots(mat.charpoly(x=Dummy('x'), simplify=simplify), **flags)
else:
eigs = roots(mat.charpoly(x=Dummy('x')), **flags)
# make sure the algebraic multiplicty sums to the
# size of the matrix
if error_when_incomplete and (sum(eigs.values()) if
isinstance(eigs, dict) else len(eigs)) != self.cols:
raise MatrixError("Could not compute eigenvalues for {}".format(self))
# Since 'simplify' flag is unsupported in roots()
# simplify() function will be applied once at the end of the routine.
if not simplify:
return eigs
if not isinstance(simplify, FunctionType):
simplify = _simplify
# With 'multiple' flag set true, simplify() will be mapped for the list
# Otherwise, simplify() will be mapped for the keys of the dictionary
if not multiple:
return {simplify(key): value for key, value in eigs.items()}
else:
return [simplify(value) for value in eigs]
def eigenvects(self, error_when_incomplete=True, iszerofunc=_iszero, **flags):
"""Return list of triples (eigenval, multiplicity, basis).
The flag ``simplify`` has two effects:
1) if bool(simplify) is True, as_content_primitive()
will be used to tidy up normalization artifacts;
2) if nullspace needs simplification to compute the
basis, the simplify flag will be passed on to the
nullspace routine which will interpret it there.
Parameters
==========
error_when_incomplete : bool
Raise an error when not all eigenvalues are computed. This is
caused by ``roots`` not returning a full list of eigenvalues.
If the matrix contains any Floats, they will be changed to Rationals
for computation purposes, but the answers will be returned after being
evaluated with evalf. If it is desired to removed small imaginary
portions during the evalf step, pass a value for the ``chop`` flag.
"""
from sympy.matrices import eye
simplify = flags.get('simplify', True)
if not isinstance(simplify, FunctionType):
simpfunc = _simplify if simplify else lambda x: x
primitive = flags.get('simplify', False)
chop = flags.pop('chop', False)
flags.pop('multiple', None) # remove this if it's there
mat = self
# roots doesn't like Floats, so replace them with Rationals
has_floats = any(v.has(Float) for v in self)
if has_floats:
mat = mat.applyfunc(lambda x: nsimplify(x, rational=True))
def eigenspace(eigenval):
"""Get a basis for the eigenspace for a particular eigenvalue"""
m = mat - self.eye(mat.rows) * eigenval
ret = m.nullspace(iszerofunc=iszerofunc)
# the nullspace for a real eigenvalue should be
# non-trivial. If we didn't find an eigenvector, try once
# more a little harder
if len(ret) == 0 and simplify:
ret = m.nullspace(iszerofunc=iszerofunc, simplify=True)
if len(ret) == 0:
raise NotImplementedError(
"Can't evaluate eigenvector for eigenvalue %s" % eigenval)
return ret
eigenvals = mat.eigenvals(rational=False,
error_when_incomplete=error_when_incomplete,
**flags)
ret = [(val, mult, eigenspace(val)) for val, mult in
sorted(eigenvals.items(), key=default_sort_key)]
if primitive:
# if the primitive flag is set, get rid of any common
# integer denominators
def denom_clean(l):
from sympy import gcd
return [(v / gcd(list(v))).applyfunc(simpfunc) for v in l]
ret = [(val, mult, denom_clean(es)) for val, mult, es in ret]
if has_floats:
# if we had floats to start with, turn the eigenvectors to floats
ret = [(val.evalf(chop=chop), mult, [v.evalf(chop=chop) for v in es]) for val, mult, es in ret]
return ret
def is_diagonalizable(self, reals_only=False, **kwargs):
"""Returns true if a matrix is diagonalizable.
Parameters
==========
reals_only : bool. If reals_only=True, determine whether the matrix can be
diagonalized without complex numbers. (Default: False)
kwargs
======
clear_cache : bool. If True, clear the result of any computations when finished.
(Default: True)
Examples
========
>>> from sympy import Matrix
>>> m = Matrix(3, 3, [1, 2, 0, 0, 3, 0, 2, -4, 2])
>>> m
Matrix([
[1, 2, 0],
[0, 3, 0],
[2, -4, 2]])
>>> m.is_diagonalizable()
True
>>> m = Matrix(2, 2, [0, 1, 0, 0])
>>> m
Matrix([
[0, 1],
[0, 0]])
>>> m.is_diagonalizable()
False
>>> m = Matrix(2, 2, [0, 1, -1, 0])
>>> m
Matrix([
[ 0, 1],
[-1, 0]])
>>> m.is_diagonalizable()
True
>>> m.is_diagonalizable(reals_only=True)
False
See Also
========
is_diagonal
diagonalize
"""
clear_cache = kwargs.get('clear_cache', True)
if 'clear_subproducts' in kwargs:
clear_cache = kwargs.get('clear_subproducts')
def cleanup():
"""Clears any cached values if requested"""
if clear_cache:
self._cache_eigenvects = None
self._cache_is_diagonalizable = None
if not self.is_square:
cleanup()
return False
# use the cached value if we have it
if self._cache_is_diagonalizable is not None:
ret = self._cache_is_diagonalizable
cleanup()
return ret
if all(e.is_real for e in self) and self.is_symmetric():
# every real symmetric matrix is real diagonalizable
self._cache_is_diagonalizable = True
cleanup()
return True
self._cache_eigenvects = self.eigenvects(simplify=True)
ret = True
for val, mult, basis in self._cache_eigenvects:
# if we have a complex eigenvalue
if reals_only and not val.is_real:
ret = False
# if the geometric multiplicity doesn't equal the algebraic
if mult != len(basis):
ret = False
cleanup()
return ret
def jordan_form(self, calc_transform=True, **kwargs):
"""Return `(P, J)` where `J` is a Jordan block
matrix and `P` is a matrix such that
`self == P*J*P**-1`
Parameters
==========
calc_transform : bool
If ``False``, then only `J` is returned.
chop : bool
All matrices are convered to exact types when computing
eigenvalues and eigenvectors. As a result, there may be
approximation errors. If ``chop==True``, these errors
will be truncated.
Examples
========
>>> from sympy import Matrix
>>> m = Matrix([[ 6, 5, -2, -3], [-3, -1, 3, 3], [ 2, 1, -2, -3], [-1, 1, 5, 5]])
>>> P, J = m.jordan_form()
>>> J
Matrix([
[2, 1, 0, 0],
[0, 2, 0, 0],
[0, 0, 2, 1],
[0, 0, 0, 2]])
See Also
========
jordan_block
"""
if not self.is_square:
raise NonSquareMatrixError("Only square matrices have Jordan forms")
chop = kwargs.pop('chop', False)
mat = self
has_floats = any(v.has(Float) for v in self)
if has_floats:
try:
max_prec = max(term._prec for term in self._mat if isinstance(term, Float))
except ValueError:
# if no term in the matrix is explicitly a Float calling max()
# will throw a error so setting max_prec to default value of 53
max_prec = 53
# setting minimum max_dps to 15 to prevent loss of precision in
# matrix containing non evaluated expressions
max_dps = max(prec_to_dps(max_prec), 15)
def restore_floats(*args):
"""If `has_floats` is `True`, cast all `args` as
matrices of floats."""
if has_floats:
args = [m.evalf(prec=max_dps, chop=chop) for m in args]
if len(args) == 1:
return args[0]
return args
# cache calculations for some speedup
mat_cache = {}
def eig_mat(val, pow):
"""Cache computations of (self - val*I)**pow for quick
retrieval"""
if (val, pow) in mat_cache:
return mat_cache[(val, pow)]
if (val, pow - 1) in mat_cache:
mat_cache[(val, pow)] = mat_cache[(val, pow - 1)] * mat_cache[(val, 1)]
else:
mat_cache[(val, pow)] = (mat - val*self.eye(self.rows))**pow
return mat_cache[(val, pow)]
# helper functions
def nullity_chain(val):
"""Calculate the sequence [0, nullity(E), nullity(E**2), ...]
until it is constant where `E = self - val*I`"""
# mat.rank() is faster than computing the null space,
# so use the rank-nullity theorem
cols = self.cols
ret = [0]
nullity = cols - eig_mat(val, 1).rank()
i = 2
while nullity != ret[-1]:
ret.append(nullity)
nullity = cols - eig_mat(val, i).rank()
i += 1
return ret
def blocks_from_nullity_chain(d):
"""Return a list of the size of each Jordan block.
If d_n is the nullity of E**n, then the number
of Jordan blocks of size n is
2*d_n - d_(n-1) - d_(n+1)"""
# d[0] is always the number of columns, so skip past it
mid = [2*d[n] - d[n - 1] - d[n + 1] for n in range(1, len(d) - 1)]
# d is assumed to plateau with "d[ len(d) ] == d[-1]", so
# 2*d_n - d_(n-1) - d_(n+1) == d_n - d_(n-1)
end = [d[-1] - d[-2]] if len(d) > 1 else [d[0]]
return mid + end
def pick_vec(small_basis, big_basis):
"""Picks a vector from big_basis that isn't in
the subspace spanned by small_basis"""
if len(small_basis) == 0:
return big_basis[0]
for v in big_basis:
_, pivots = self.hstack(*(small_basis + [v])).echelon_form(with_pivots=True)
if pivots[-1] == len(small_basis):
return v
# roots doesn't like Floats, so replace them with Rationals
if has_floats:
mat = mat.applyfunc(lambda x: nsimplify(x, rational=True))
# first calculate the jordan block structure
eigs = mat.eigenvals()
# make sure that we found all the roots by counting
# the algebraic multiplicity
if sum(m for m in eigs.values()) != mat.cols:
raise MatrixError("Could not compute eigenvalues for {}".format(mat))
# most matrices have distinct eigenvalues
# and so are diagonalizable. In this case, don't
# do extra work!
if len(eigs.keys()) == mat.cols:
blocks = list(sorted(eigs.keys(), key=default_sort_key))
jordan_mat = mat.diag(*blocks)
if not calc_transform:
return restore_floats(jordan_mat)
jordan_basis = [eig_mat(eig, 1).nullspace()[0] for eig in blocks]
basis_mat = mat.hstack(*jordan_basis)
return restore_floats(basis_mat, jordan_mat)
block_structure = []
for eig in sorted(eigs.keys(), key=default_sort_key):
chain = nullity_chain(eig)
block_sizes = blocks_from_nullity_chain(chain)
# if block_sizes == [a, b, c, ...], then the number of
# Jordan blocks of size 1 is a, of size 2 is b, etc.
# create an array that has (eig, block_size) with one
# entry for each block
size_nums = [(i+1, num) for i, num in enumerate(block_sizes)]
# we expect larger Jordan blocks to come earlier
size_nums.reverse()
block_structure.extend(
(eig, size) for size, num in size_nums for _ in range(num))
blocks = (mat.jordan_block(size=size, eigenvalue=eig) for eig, size in block_structure)
jordan_mat = mat.diag(*blocks)
if not calc_transform:
return restore_floats(jordan_mat)
# For each generalized eigenspace, calculate a basis.
# We start by looking for a vector in null( (A - eig*I)**n )
# which isn't in null( (A - eig*I)**(n-1) ) where n is
# the size of the Jordan block
#
# Ideally we'd just loop through block_structure and
# compute each generalized eigenspace. However, this
# causes a lot of unneeded computation. Instead, we
# go through the eigenvalues separately, since we know
# their generalized eigenspaces must have bases that
# are linearly independent.
jordan_basis = []
for eig in sorted(eigs.keys(), key=default_sort_key):
eig_basis = []
for block_eig, size in block_structure:
if block_eig != eig:
continue
null_big = (eig_mat(eig, size)).nullspace()
null_small = (eig_mat(eig, size - 1)).nullspace()
# we want to pick something that is in the big basis
# and not the small, but also something that is independent
# of any other generalized eigenvectors from a different
# generalized eigenspace sharing the same eigenvalue.
vec = pick_vec(null_small + eig_basis, null_big)
new_vecs = [(eig_mat(eig, i))*vec for i in range(size)]
eig_basis.extend(new_vecs)
jordan_basis.extend(reversed(new_vecs))
basis_mat = mat.hstack(*jordan_basis)
return restore_floats(basis_mat, jordan_mat)
def left_eigenvects(self, **flags):
"""Returns left eigenvectors and eigenvalues.
This function returns the list of triples (eigenval, multiplicity,
basis) for the left eigenvectors. Options are the same as for
eigenvects(), i.e. the ``**flags`` arguments gets passed directly to
eigenvects().
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[0, 1, 1], [1, 0, 0], [1, 1, 1]])
>>> M.eigenvects()
[(-1, 1, [Matrix([
[-1],
[ 1],
[ 0]])]), (0, 1, [Matrix([
[ 0],
[-1],
[ 1]])]), (2, 1, [Matrix([
[2/3],
[1/3],
[ 1]])])]
>>> M.left_eigenvects()
[(-1, 1, [Matrix([[-2, 1, 1]])]), (0, 1, [Matrix([[-1, -1, 1]])]), (2,
1, [Matrix([[1, 1, 1]])])]
"""
eigs = self.transpose().eigenvects(**flags)
return [(val, mult, [l.transpose() for l in basis]) for val, mult, basis in eigs]
def singular_values(self):
"""Compute the singular values of a Matrix
Examples
========
>>> from sympy import Matrix, Symbol
>>> x = Symbol('x', real=True)
>>> A = Matrix([[0, 1, 0], [0, x, 0], [-1, 0, 0]])
>>> A.singular_values()
[sqrt(x**2 + 1), 1, 0]
See Also
========
condition_number
"""
mat = self
# Compute eigenvalues of A.H A
valmultpairs = (mat.H * mat).eigenvals()
# Expands result from eigenvals into a simple list
vals = []
for k, v in valmultpairs.items():
vals += [sqrt(k)] * v # dangerous! same k in several spots!
# sort them in descending order
vals.sort(reverse=True, key=default_sort_key)
return vals
class MatrixCalculus(MatrixCommon):
"""Provides calculus-related matrix operations."""
def diff(self, *args, **kwargs):
"""Calculate the derivative of each element in the matrix.
``args`` will be passed to the ``integrate`` function.
Examples
========
>>> from sympy.matrices import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.diff(x)
Matrix([
[1, 0],
[0, 0]])
See Also
========
integrate
limit
"""
# XXX this should be handled here rather than in Derivative
from sympy import Derivative
kwargs.setdefault('evaluate', True)
deriv = Derivative(self, *args, evaluate=True)
if not isinstance(self, Basic):
return deriv.as_mutable()
else:
return deriv
def _eval_derivative(self, arg):
return self.applyfunc(lambda x: x.diff(arg))
def _accept_eval_derivative(self, s):
return s._visit_eval_derivative_array(self)
def _visit_eval_derivative_scalar(self, base):
# Types are (base: scalar, self: matrix)
return self.applyfunc(lambda x: base.diff(x))
def _visit_eval_derivative_array(self, base):
# Types are (base: array/matrix, self: matrix)
from sympy import derive_by_array
return derive_by_array(base, self)
def integrate(self, *args):
"""Integrate each element of the matrix. ``args`` will
be passed to the ``integrate`` function.
Examples
========
>>> from sympy.matrices import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.integrate((x, ))
Matrix([
[x**2/2, x*y],
[ x, 0]])
>>> M.integrate((x, 0, 2))
Matrix([
[2, 2*y],
[2, 0]])
See Also
========
limit
diff
"""
return self.applyfunc(lambda x: x.integrate(*args))
def jacobian(self, X):
"""Calculates the Jacobian matrix (derivative of a vector-valued function).
Parameters
==========
self : vector of expressions representing functions f_i(x_1, ..., x_n).
X : set of x_i's in order, it can be a list or a Matrix
Both self and X can be a row or a column matrix in any order
(i.e., jacobian() should always work).
Examples
========
>>> from sympy import sin, cos, Matrix
>>> from sympy.abc import rho, phi
>>> X = Matrix([rho*cos(phi), rho*sin(phi), rho**2])
>>> Y = Matrix([rho, phi])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)],
[ 2*rho, 0]])
>>> X = Matrix([rho*cos(phi), rho*sin(phi)])
>>> X.jacobian(Y)
Matrix([
[cos(phi), -rho*sin(phi)],
[sin(phi), rho*cos(phi)]])
See Also
========
hessian
wronskian
"""
if not isinstance(X, MatrixBase):
X = self._new(X)
# Both X and self can be a row or a column matrix, so we need to make
# sure all valid combinations work, but everything else fails:
if self.shape[0] == 1:
m = self.shape[1]
elif self.shape[1] == 1:
m = self.shape[0]
else:
raise TypeError("self must be a row or a column matrix")
if X.shape[0] == 1:
n = X.shape[1]
elif X.shape[1] == 1:
n = X.shape[0]
else:
raise TypeError("X must be a row or a column matrix")
# m is the number of functions and n is the number of variables
# computing the Jacobian is now easy:
return self._new(m, n, lambda j, i: self[j].diff(X[i]))
def limit(self, *args):
"""Calculate the limit of each element in the matrix.
``args`` will be passed to the ``limit`` function.
Examples
========
>>> from sympy.matrices import Matrix
>>> from sympy.abc import x, y
>>> M = Matrix([[x, y], [1, 0]])
>>> M.limit(x, 2)
Matrix([
[2, y],
[1, 0]])
See Also
========
integrate
diff
"""
return self.applyfunc(lambda x: x.limit(*args))
# https://github.com/sympy/sympy/pull/12854
class MatrixDeprecated(MatrixCommon):
"""A class to house deprecated matrix methods."""
def _legacy_array_dot(self, b):
"""Compatibility function for deprecated behavior of ``matrix.dot(vector)``
"""
from .dense import Matrix
if not isinstance(b, MatrixBase):
if is_sequence(b):
if len(b) != self.cols and len(b) != self.rows:
raise ShapeError(
"Dimensions incorrect for dot product: %s, %s" % (
self.shape, len(b)))
return self.dot(Matrix(b))
else:
raise TypeError(
"`b` must be an ordered iterable or Matrix, not %s." %
type(b))
mat = self
if mat.cols == b.rows:
if b.cols != 1:
mat = mat.T
b = b.T
prod = flatten((mat * b).tolist())
return prod
if mat.cols == b.cols:
return mat.dot(b.T)
elif mat.rows == b.rows:
return mat.T.dot(b)
else:
raise ShapeError("Dimensions incorrect for dot product: %s, %s" % (
self.shape, b.shape))
def berkowitz_charpoly(self, x=Dummy('lambda'), simplify=_simplify):
return self.charpoly(x=x)
def berkowitz_det(self):
"""Computes determinant using Berkowitz method.
See Also
========
det
berkowitz
"""
return self.det(method='berkowitz')
def berkowitz_eigenvals(self, **flags):
"""Computes eigenvalues of a Matrix using Berkowitz method.
See Also
========
berkowitz
"""
return self.eigenvals(**flags)
def berkowitz_minors(self):
"""Computes principal minors using Berkowitz method.
See Also
========
berkowitz
"""
sign, minors = S.One, []
for poly in self.berkowitz():
minors.append(sign * poly[-1])
sign = -sign
return tuple(minors)
def berkowitz(self):
from sympy.matrices import zeros
berk = ((1,),)
if not self:
return berk
if not self.is_square:
raise NonSquareMatrixError()
A, N = self, self.rows
transforms = [0] * (N - 1)
for n in range(N, 1, -1):
T, k = zeros(n + 1, n), n - 1
R, C = -A[k, :k], A[:k, k]
A, a = A[:k, :k], -A[k, k]
items = [C]
for i in range(0, n - 2):
items.append(A * items[i])
for i, B in enumerate(items):
items[i] = (R * B)[0, 0]
items = [S.One, a] + items
for i in range(n):
T[i:, i] = items[:n - i + 1]
transforms[k - 1] = T
polys = [self._new([S.One, -A[0, 0]])]
for i, T in enumerate(transforms):
polys.append(T * polys[i])
return berk + tuple(map(tuple, polys))
def cofactorMatrix(self, method="berkowitz"):
return self.cofactor_matrix(method=method)
def det_bareis(self):
return self.det(method='bareiss')
def det_bareiss(self):
"""Compute matrix determinant using Bareiss' fraction-free
algorithm which is an extension of the well known Gaussian
elimination method. This approach is best suited for dense
symbolic matrices and will result in a determinant with
minimal number of fractions. It means that less term
rewriting is needed on resulting formulae.
TODO: Implement algorithm for sparse matrices (SFF),
http://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps.
See Also
========
det
berkowitz_det
"""
return self.det(method='bareiss')
def det_LU_decomposition(self):
"""Compute matrix determinant using LU decomposition
Note that this method fails if the LU decomposition itself
fails. In particular, if the matrix has no inverse this method
will fail.
TODO: Implement algorithm for sparse matrices (SFF),
http://www.eecis.udel.edu/~saunders/papers/sffge/it5.ps.
See Also
========
det
det_bareiss
berkowitz_det
"""
return self.det(method='lu')
def jordan_cell(self, eigenval, n):
return self.jordan_block(size=n, eigenvalue=eigenval)
def jordan_cells(self, calc_transformation=True):
P, J = self.jordan_form()
return P, J.get_diag_blocks()
def minorEntry(self, i, j, method="berkowitz"):
return self.minor(i, j, method=method)
def minorMatrix(self, i, j):
return self.minor_submatrix(i, j)
def permuteBkwd(self, perm):
"""Permute the rows of the matrix with the given permutation in reverse."""
return self.permute_rows(perm, direction='backward')
def permuteFwd(self, perm):
"""Permute the rows of the matrix with the given permutation."""
return self.permute_rows(perm, direction='forward')
class MatrixBase(MatrixDeprecated,
MatrixCalculus,
MatrixEigen,
MatrixCommon):
"""Base class for matrix objects."""
# Added just for numpy compatibility
__array_priority__ = 11
is_Matrix = True
_class_priority = 3
_sympify = staticmethod(sympify)
__hash__ = None # Mutable
# Defined here the same as on Basic.
# We don't define _repr_png_ here because it would add a large amount of
# data to any notebook containing SymPy expressions, without adding
# anything useful to the notebook. It can still enabled manually, e.g.,
# for the qtconsole, with init_printing().
def _repr_latex_(self):
"""
IPython/Jupyter LaTeX printing
To change the behavior of this (e.g., pass in some settings to LaTeX),
use init_printing(). init_printing() will also enable LaTeX printing
for built in numeric types like ints and container types that contain
SymPy objects, like lists and dictionaries of expressions.
"""
from sympy.printing.latex import latex
s = latex(self, mode='plain')
return "$\\displaystyle %s$" % s
_repr_latex_orig = _repr_latex_
def __array__(self, dtype=object):
from .dense import matrix2numpy
return matrix2numpy(self, dtype=dtype)
def __getattr__(self, attr):
if attr in ('diff', 'integrate', 'limit'):
def doit(*args):
item_doit = lambda item: getattr(item, attr)(*args)
return self.applyfunc(item_doit)
return doit
else:
raise AttributeError(
"%s has no attribute %s." % (self.__class__.__name__, attr))
def __len__(self):
"""Return the number of elements of self.
Implemented mainly so bool(Matrix()) == False.
"""
return self.rows * self.cols
def __mathml__(self):
mml = ""
for i in range(self.rows):
mml += "<matrixrow>"
for j in range(self.cols):
mml += self[i, j].__mathml__()
mml += "</matrixrow>"
return "<matrix>" + mml + "</matrix>"
# needed for python 2 compatibility
def __ne__(self, other):
return not self == other
def _matrix_pow_by_jordan_blocks(self, num):
from sympy.matrices import diag, MutableMatrix
from sympy import binomial
def jordan_cell_power(jc, n):
N = jc.shape[0]
l = jc[0, 0]
if l == 0 and (n < N - 1) != False:
raise ValueError("Matrix det == 0; not invertible")
elif l == 0 and N > 1 and n % 1 != 0:
raise ValueError("Non-integer power cannot be evaluated")
for i in range(N):
for j in range(N-i):
bn = binomial(n, i)
if isinstance(bn, binomial):
bn = bn._eval_expand_func()
jc[j, i+j] = l**(n-i)*bn
P, J = self.jordan_form()
jordan_cells = J.get_diag_blocks()
# Make sure jordan_cells matrices are mutable:
jordan_cells = [MutableMatrix(j) for j in jordan_cells]
for j in jordan_cells:
jordan_cell_power(j, num)
return self._new(P*diag(*jordan_cells)*P.inv())
def __repr__(self):
return sstr(self)
def __str__(self):
if self.rows == 0 or self.cols == 0:
return 'Matrix(%s, %s, [])' % (self.rows, self.cols)
return "Matrix(%s)" % str(self.tolist())
def _diagonalize_clear_subproducts(self):
del self._is_symbolic
del self._is_symmetric
del self._eigenvects
def _format_str(self, printer=None):
if not printer:
from sympy.printing.str import StrPrinter
printer = StrPrinter()
# Handle zero dimensions:
if self.rows == 0 or self.cols == 0:
return 'Matrix(%s, %s, [])' % (self.rows, self.cols)
if self.rows == 1:
return "Matrix([%s])" % self.table(printer, rowsep=',\n')
return "Matrix([\n%s])" % self.table(printer, rowsep=',\n')
@classmethod
def _handle_creation_inputs(cls, *args, **kwargs):
"""Return the number of rows, cols and flat matrix elements.
Examples
========
>>> from sympy import Matrix, I
Matrix can be constructed as follows:
* from a nested list of iterables
>>> Matrix( ((1, 2+I), (3, 4)) )
Matrix([
[1, 2 + I],
[3, 4]])
* from un-nested iterable (interpreted as a column)
>>> Matrix( [1, 2] )
Matrix([
[1],
[2]])
* from un-nested iterable with dimensions
>>> Matrix(1, 2, [1, 2] )
Matrix([[1, 2]])
* from no arguments (a 0 x 0 matrix)
>>> Matrix()
Matrix(0, 0, [])
* from a rule
>>> Matrix(2, 2, lambda i, j: i/(j + 1) )
Matrix([
[0, 0],
[1, 1/2]])
"""
from sympy.matrices.sparse import SparseMatrix
flat_list = None
if len(args) == 1:
# Matrix(SparseMatrix(...))
if isinstance(args[0], SparseMatrix):
return args[0].rows, args[0].cols, flatten(args[0].tolist())
# Matrix(Matrix(...))
elif isinstance(args[0], MatrixBase):
return args[0].rows, args[0].cols, args[0]._mat
# Matrix(MatrixSymbol('X', 2, 2))
elif isinstance(args[0], Basic) and args[0].is_Matrix:
return args[0].rows, args[0].cols, args[0].as_explicit()._mat
# Matrix(numpy.ones((2, 2)))
elif hasattr(args[0], "__array__"):
# NumPy array or matrix or some other object that implements
# __array__. So let's first use this method to get a
# numpy.array() and then make a python list out of it.
arr = args[0].__array__()
if len(arr.shape) == 2:
rows, cols = arr.shape[0], arr.shape[1]
flat_list = [cls._sympify(i) for i in arr.ravel()]
return rows, cols, flat_list
elif len(arr.shape) == 1:
rows, cols = arr.shape[0], 1
flat_list = [S.Zero] * rows
for i in range(len(arr)):
flat_list[i] = cls._sympify(arr[i])
return rows, cols, flat_list
else:
raise NotImplementedError(
"SymPy supports just 1D and 2D matrices")
# Matrix([1, 2, 3]) or Matrix([[1, 2], [3, 4]])
elif is_sequence(args[0]) \
and not isinstance(args[0], DeferredVector):
in_mat = []
ncol = set()
for row in args[0]:
if isinstance(row, MatrixBase):
in_mat.extend(row.tolist())
if row.cols or row.rows: # only pay attention if it's not 0x0
ncol.add(row.cols)
else:
in_mat.append(row)
try:
ncol.add(len(row))
except TypeError:
ncol.add(1)
if len(ncol) > 1:
raise ValueError("Got rows of variable lengths: %s" %
sorted(list(ncol)))
cols = ncol.pop() if ncol else 0
rows = len(in_mat) if cols else 0
if rows:
if not is_sequence(in_mat[0]):
cols = 1
flat_list = [cls._sympify(i) for i in in_mat]
return rows, cols, flat_list
flat_list = []
for j in range(rows):
for i in range(cols):
flat_list.append(cls._sympify(in_mat[j][i]))
elif len(args) == 3:
rows = as_int(args[0])
cols = as_int(args[1])
if rows < 0 or cols < 0:
raise ValueError("Cannot create a {} x {} matrix. "
"Both dimensions must be positive".format(rows, cols))
# Matrix(2, 2, lambda i, j: i+j)
if len(args) == 3 and isinstance(args[2], Callable):
op = args[2]
flat_list = []
for i in range(rows):
flat_list.extend(
[cls._sympify(op(cls._sympify(i), cls._sympify(j)))
for j in range(cols)])
# Matrix(2, 2, [1, 2, 3, 4])
elif len(args) == 3 and is_sequence(args[2]):
flat_list = args[2]
if len(flat_list) != rows * cols:
raise ValueError(
'List length should be equal to rows*columns')
flat_list = [cls._sympify(i) for i in flat_list]
# Matrix()
elif len(args) == 0:
# Empty Matrix
rows = cols = 0
flat_list = []
if flat_list is None:
raise TypeError("Data type not understood")
return rows, cols, flat_list
def _setitem(self, key, value):
"""Helper to set value at location given by key.
Examples
========
>>> from sympy import Matrix, I, zeros, ones
>>> m = Matrix(((1, 2+I), (3, 4)))
>>> m
Matrix([
[1, 2 + I],
[3, 4]])
>>> m[1, 0] = 9
>>> m
Matrix([
[1, 2 + I],
[9, 4]])
>>> m[1, 0] = [[0, 1]]
To replace row r you assign to position r*m where m
is the number of columns:
>>> M = zeros(4)
>>> m = M.cols
>>> M[3*m] = ones(1, m)*2; M
Matrix([
[0, 0, 0, 0],
[0, 0, 0, 0],
[0, 0, 0, 0],
[2, 2, 2, 2]])
And to replace column c you can assign to position c:
>>> M[2] = ones(m, 1)*4; M
Matrix([
[0, 0, 4, 0],
[0, 0, 4, 0],
[0, 0, 4, 0],
[2, 2, 4, 2]])
"""
from .dense import Matrix
is_slice = isinstance(key, slice)
i, j = key = self.key2ij(key)
is_mat = isinstance(value, MatrixBase)
if type(i) is slice or type(j) is slice:
if is_mat:
self.copyin_matrix(key, value)
return
if not isinstance(value, Expr) and is_sequence(value):
self.copyin_list(key, value)
return
raise ValueError('unexpected value: %s' % value)
else:
if (not is_mat and
not isinstance(value, Basic) and is_sequence(value)):
value = Matrix(value)
is_mat = True
if is_mat:
if is_slice:
key = (slice(*divmod(i, self.cols)),
slice(*divmod(j, self.cols)))
else:
key = (slice(i, i + value.rows),
slice(j, j + value.cols))
self.copyin_matrix(key, value)
else:
return i, j, self._sympify(value)
return
def add(self, b):
"""Return self + b """
return self + b
def cholesky_solve(self, rhs):
"""Solves Ax = B using Cholesky decomposition,
for a general square non-singular matrix.
For a non-square matrix with rows > cols,
the least squares solution is returned.
See Also
========
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
"""
hermitian = True
if self.is_symmetric():
hermitian = False
L = self._cholesky(hermitian=hermitian)
elif self.is_hermitian:
L = self._cholesky(hermitian=hermitian)
elif self.rows >= self.cols:
L = (self.H * self)._cholesky(hermitian=hermitian)
rhs = self.H * rhs
else:
raise NotImplementedError('Under-determined System. '
'Try M.gauss_jordan_solve(rhs)')
Y = L._lower_triangular_solve(rhs)
if hermitian:
return (L.H)._upper_triangular_solve(Y)
else:
return (L.T)._upper_triangular_solve(Y)
def cholesky(self, hermitian=True):
"""Returns the Cholesky-type decomposition L of a matrix A
such that L * L.H == A if hermitian flag is True,
or L * L.T == A if hermitian is False.
A must be a Hermitian positive-definite matrix if hermitian is True,
or a symmetric matrix if it is False.
Examples
========
>>> from sympy.matrices import Matrix
>>> A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
>>> A.cholesky()
Matrix([
[ 5, 0, 0],
[ 3, 3, 0],
[-1, 1, 3]])
>>> A.cholesky() * A.cholesky().T
Matrix([
[25, 15, -5],
[15, 18, 0],
[-5, 0, 11]])
The matrix can have complex entries:
>>> from sympy import I
>>> A = Matrix(((9, 3*I), (-3*I, 5)))
>>> A.cholesky()
Matrix([
[ 3, 0],
[-I, 2]])
>>> A.cholesky() * A.cholesky().H
Matrix([
[ 9, 3*I],
[-3*I, 5]])
Non-hermitian Cholesky-type decomposition may be useful when the
matrix is not positive-definite.
>>> A = Matrix([[1, 2], [2, 1]])
>>> L = A.cholesky(hermitian=False)
>>> L
Matrix([
[1, 0],
[2, sqrt(3)*I]])
>>> L*L.T == A
True
See Also
========
LDLdecomposition
LUdecomposition
QRdecomposition
"""
if not self.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not self.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not self.is_symmetric():
raise ValueError("Matrix must be symmetric.")
return self._cholesky(hermitian=hermitian)
def condition_number(self):
"""Returns the condition number of a matrix.
This is the maximum singular value divided by the minimum singular value
Examples
========
>>> from sympy import Matrix, S
>>> A = Matrix([[1, 0, 0], [0, 10, 0], [0, 0, S.One/10]])
>>> A.condition_number()
100
See Also
========
singular_values
"""
if not self:
return S.Zero
singularvalues = self.singular_values()
return Max(*singularvalues) / Min(*singularvalues)
def copy(self):
"""
Returns the copy of a matrix.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.copy()
Matrix([
[1, 2],
[3, 4]])
"""
return self._new(self.rows, self.cols, self._mat)
def cross(self, b):
r"""
Return the cross product of ``self`` and ``b`` relaxing the condition
of compatible dimensions: if each has 3 elements, a matrix of the
same type and shape as ``self`` will be returned. If ``b`` has the same
shape as ``self`` then common identities for the cross product (like
`a \times b = - b \times a`) will hold.
Parameters
==========
b : 3x1 or 1x3 Matrix
See Also
========
dot
multiply
multiply_elementwise
"""
if not is_sequence(b):
raise TypeError(
"`b` must be an ordered iterable or Matrix, not %s." %
type(b))
if not (self.rows * self.cols == b.rows * b.cols == 3):
raise ShapeError("Dimensions incorrect for cross product: %s x %s" %
((self.rows, self.cols), (b.rows, b.cols)))
else:
return self._new(self.rows, self.cols, (
(self[1] * b[2] - self[2] * b[1]),
(self[2] * b[0] - self[0] * b[2]),
(self[0] * b[1] - self[1] * b[0])))
@property
def D(self):
"""Return Dirac conjugate (if self.rows == 4).
Examples
========
>>> from sympy import Matrix, I, eye
>>> m = Matrix((0, 1 + I, 2, 3))
>>> m.D
Matrix([[0, 1 - I, -2, -3]])
>>> m = (eye(4) + I*eye(4))
>>> m[0, 3] = 2
>>> m.D
Matrix([
[1 - I, 0, 0, 0],
[ 0, 1 - I, 0, 0],
[ 0, 0, -1 + I, 0],
[ 2, 0, 0, -1 + I]])
If the matrix does not have 4 rows an AttributeError will be raised
because this property is only defined for matrices with 4 rows.
>>> Matrix(eye(2)).D
Traceback (most recent call last):
...
AttributeError: Matrix has no attribute D.
See Also
========
conjugate: By-element conjugation
H: Hermite conjugation
"""
from sympy.physics.matrices import mgamma
if self.rows != 4:
# In Python 3.2, properties can only return an AttributeError
# so we can't raise a ShapeError -- see commit which added the
# first line of this inline comment. Also, there is no need
# for a message since MatrixBase will raise the AttributeError
raise AttributeError
return self.H * mgamma(0)
def diagonal_solve(self, rhs):
"""Solves Ax = B efficiently, where A is a diagonal Matrix,
with non-zero diagonal entries.
Examples
========
>>> from sympy.matrices import Matrix, eye
>>> A = eye(2)*2
>>> B = Matrix([[1, 2], [3, 4]])
>>> A.diagonal_solve(B) == B/2
True
See Also
========
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
"""
if not self.is_diagonal:
raise TypeError("Matrix should be diagonal")
if rhs.rows != self.rows:
raise TypeError("Size mis-match")
return self._diagonal_solve(rhs)
def dot(self, b, hermitian=None, conjugate_convention=None):
"""Return the dot or inner product of two vectors of equal length.
Here ``self`` must be a ``Matrix`` of size 1 x n or n x 1, and ``b``
must be either a matrix of size 1 x n, n x 1, or a list/tuple of length n.
A scalar is returned.
By default, ``dot`` does not conjugate ``self`` or ``b``, even if there are
complex entries. Set ``hermitian=True`` (and optionally a ``conjugate_convention``)
to compute the hermitian inner product.
Possible kwargs are ``hermitian`` and ``conjugate_convention``.
If ``conjugate_convention`` is ``"left"``, ``"math"`` or ``"maths"``,
the conjugate of the first vector (``self``) is used. If ``"right"``
or ``"physics"`` is specified, the conjugate of the second vector ``b`` is used.
Examples
========
>>> from sympy import Matrix
>>> M = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> v = Matrix([1, 1, 1])
>>> M.row(0).dot(v)
6
>>> M.col(0).dot(v)
12
>>> v = [3, 2, 1]
>>> M.row(0).dot(v)
10
>>> from sympy import I
>>> q = Matrix([1*I, 1*I, 1*I])
>>> q.dot(q, hermitian=False)
-3
>>> q.dot(q, hermitian=True)
3
>>> q1 = Matrix([1, 1, 1*I])
>>> q.dot(q1, hermitian=True, conjugate_convention="maths")
1 - 2*I
>>> q.dot(q1, hermitian=True, conjugate_convention="physics")
1 + 2*I
See Also
========
cross
multiply
multiply_elementwise
"""
from .dense import Matrix
if not isinstance(b, MatrixBase):
if is_sequence(b):
if len(b) != self.cols and len(b) != self.rows:
raise ShapeError(
"Dimensions incorrect for dot product: %s, %s" % (
self.shape, len(b)))
return self.dot(Matrix(b))
else:
raise TypeError(
"`b` must be an ordered iterable or Matrix, not %s." %
type(b))
mat = self
if (1 not in mat.shape) or (1 not in b.shape) :
SymPyDeprecationWarning(
feature="Dot product of non row/column vectors",
issue=13815,
deprecated_since_version="1.2",
useinstead="* to take matrix products").warn()
return mat._legacy_array_dot(b)
if len(mat) != len(b):
raise ShapeError("Dimensions incorrect for dot product: %s, %s" % (self.shape, b.shape))
n = len(mat)
if mat.shape != (1, n):
mat = mat.reshape(1, n)
if b.shape != (n, 1):
b = b.reshape(n, 1)
# Now ``mat`` is a row vector and ``b`` is a column vector.
# If it so happens that only conjugate_convention is passed
# then automatically set hermitian to True. If only hermitian
# is true but no conjugate_convention is not passed then
# automatically set it to ``"maths"``
if conjugate_convention is not None and hermitian is None:
hermitian = True
if hermitian and conjugate_convention is None:
conjugate_convention = "maths"
if hermitian == True:
if conjugate_convention in ("maths", "left", "math"):
mat = mat.conjugate()
elif conjugate_convention in ("physics", "right"):
b = b.conjugate()
else:
raise ValueError("Unknown conjugate_convention was entered."
" conjugate_convention must be one of the"
" following: math, maths, left, physics or right.")
return (mat * b)[0]
def dual(self):
"""Returns the dual of a matrix, which is:
`(1/2)*levicivita(i, j, k, l)*M(k, l)` summed over indices `k` and `l`
Since the levicivita method is anti_symmetric for any pairwise
exchange of indices, the dual of a symmetric matrix is the zero
matrix. Strictly speaking the dual defined here assumes that the
'matrix' `M` is a contravariant anti_symmetric second rank tensor,
so that the dual is a covariant second rank tensor.
"""
from sympy import LeviCivita
from sympy.matrices import zeros
M, n = self[:, :], self.rows
work = zeros(n)
if self.is_symmetric():
return work
for i in range(1, n):
for j in range(1, n):
acum = 0
for k in range(1, n):
acum += LeviCivita(i, j, 0, k) * M[0, k]
work[i, j] = acum
work[j, i] = -acum
for l in range(1, n):
acum = 0
for a in range(1, n):
for b in range(1, n):
acum += LeviCivita(0, l, a, b) * M[a, b]
acum /= 2
work[0, l] = -acum
work[l, 0] = acum
return work
def exp(self):
"""Return the exponentiation of a square matrix."""
if not self.is_square:
raise NonSquareMatrixError(
"Exponentiation is valid only for square matrices")
try:
P, J = self.jordan_form()
cells = J.get_diag_blocks()
except MatrixError:
raise NotImplementedError(
"Exponentiation is implemented only for matrices for which the Jordan normal form can be computed")
def _jblock_exponential(b):
# This function computes the matrix exponential for one single Jordan block
nr = b.rows
l = b[0, 0]
if nr == 1:
res = exp(l)
else:
from sympy import eye
# extract the diagonal part
d = b[0, 0] * eye(nr)
# and the nilpotent part
n = b - d
# compute its exponential
nex = eye(nr)
for i in range(1, nr):
nex = nex + n ** i / factorial(i)
# combine the two parts
res = exp(b[0, 0]) * nex
return (res)
blocks = list(map(_jblock_exponential, cells))
from sympy.matrices import diag
from sympy import re
eJ = diag(*blocks)
# n = self.rows
ret = P * eJ * P.inv()
if all(value.is_real for value in self.values()):
return type(self)(re(ret))
else:
return type(self)(ret)
def gauss_jordan_solve(self, b, freevar=False):
"""
Solves Ax = b using Gauss Jordan elimination.
There may be zero, one, or infinite solutions. If one solution
exists, it will be returned. If infinite solutions exist, it will
be returned parametrically. If no solutions exist, It will throw
ValueError.
Parameters
==========
b : Matrix
The right hand side of the equation to be solved for. Must have
the same number of rows as matrix A.
freevar : List
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of arbitrary
values of free variables. Then the index of the free variables
in the solutions (column Matrix) will be returned by freevar, if
the flag `freevar` is set to `True`.
Returns
=======
x : Matrix
The matrix that will satisfy Ax = B. Will have as many rows as
matrix A has columns, and as many columns as matrix B.
params : Matrix
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of arbitrary
parameters. These arbitrary parameters are returned as params
Matrix.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 1, 1], [1, 2, 2, -1], [2, 4, 0, 6]])
>>> b = Matrix([7, 12, 4])
>>> sol, params = A.gauss_jordan_solve(b)
>>> sol
Matrix([
[-2*tau0 - 3*tau1 + 2],
[ tau0],
[ 2*tau1 + 5],
[ tau1]])
>>> params
Matrix([
[tau0],
[tau1]])
>>> A = Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 10]])
>>> b = Matrix([3, 6, 9])
>>> sol, params = A.gauss_jordan_solve(b)
>>> sol
Matrix([
[-1],
[ 2],
[ 0]])
>>> params
Matrix(0, 1, [])
See Also
========
lower_triangular_solve
upper_triangular_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv
References
==========
.. [1] https://en.wikipedia.org/wiki/Gaussian_elimination
"""
from sympy.matrices import Matrix, zeros
aug = self.hstack(self.copy(), b.copy())
row, col = aug[:, :-1].shape
# solve by reduced row echelon form
A, pivots = aug.rref(simplify=True)
A, v = A[:, :-1], A[:, -1]
pivots = list(filter(lambda p: p < col, pivots))
rank = len(pivots)
# Bring to block form
permutation = Matrix(range(col)).T
A = A.vstack(A, permutation)
for i, c in enumerate(pivots):
A.col_swap(i, c)
A, permutation = A[:-1, :], A[-1, :]
# check for existence of solutions
# rank of aug Matrix should be equal to rank of coefficient matrix
if not v[rank:, 0].is_zero:
raise ValueError("Linear system has no solution")
# Get index of free symbols (free parameters)
free_var_index = permutation[
len(pivots):] # non-pivots columns are free variables
# Free parameters
# what are current unnumbered free symbol names?
name = _uniquely_named_symbol('tau', aug,
compare=lambda i: str(i).rstrip('1234567890')).name
gen = numbered_symbols(name)
tau = Matrix([next(gen) for k in range(col - rank)]).reshape(col - rank, 1)
# Full parametric solution
V = A[:rank, rank:]
vt = v[:rank, 0]
free_sol = tau.vstack(vt - V * tau, tau)
# Undo permutation
sol = zeros(col, 1)
for k, v in enumerate(free_sol):
sol[permutation[k], 0] = v
if freevar:
return sol, tau, free_var_index
else:
return sol, tau
def inv_mod(self, m):
r"""
Returns the inverse of the matrix `K` (mod `m`), if it exists.
Method to find the matrix inverse of `K` (mod `m`) implemented in this function:
* Compute `\mathrm{adj}(K) = \mathrm{cof}(K)^t`, the adjoint matrix of `K`.
* Compute `r = 1/\mathrm{det}(K) \pmod m`.
* `K^{-1} = r\cdot \mathrm{adj}(K) \pmod m`.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix(2, 2, [1, 2, 3, 4])
>>> A.inv_mod(5)
Matrix([
[3, 1],
[4, 2]])
>>> A.inv_mod(3)
Matrix([
[1, 1],
[0, 1]])
"""
if not self.is_square:
raise NonSquareMatrixError()
N = self.cols
det_K = self.det()
det_inv = None
try:
det_inv = mod_inverse(det_K, m)
except ValueError:
raise ValueError('Matrix is not invertible (mod %d)' % m)
K_adj = self.adjugate()
K_inv = self.__class__(N, N,
[det_inv * K_adj[i, j] % m for i in range(N) for
j in range(N)])
return K_inv
def inverse_ADJ(self, iszerofunc=_iszero):
"""Calculates the inverse using the adjugate matrix and a determinant.
See Also
========
inv
inverse_LU
inverse_GE
"""
if not self.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
d = self.det(method='berkowitz')
zero = d.equals(0)
if zero is None:
# if equals() can't decide, will rref be able to?
ok = self.rref(simplify=True)[0]
zero = any(iszerofunc(ok[j, j]) for j in range(ok.rows))
if zero:
raise ValueError("Matrix det == 0; not invertible.")
return self.adjugate() / d
def inverse_GE(self, iszerofunc=_iszero):
"""Calculates the inverse using Gaussian elimination.
See Also
========
inv
inverse_LU
inverse_ADJ
"""
from .dense import Matrix
if not self.is_square:
raise NonSquareMatrixError("A Matrix must be square to invert.")
big = Matrix.hstack(self.as_mutable(), Matrix.eye(self.rows))
red = big.rref(iszerofunc=iszerofunc, simplify=True)[0]
if any(iszerofunc(red[j, j]) for j in range(red.rows)):
raise ValueError("Matrix det == 0; not invertible.")
return self._new(red[:, big.rows:])
def inverse_LU(self, iszerofunc=_iszero):
"""Calculates the inverse using LU decomposition.
See Also
========
inv
inverse_GE
inverse_ADJ
"""
if not self.is_square:
raise NonSquareMatrixError()
ok = self.rref(simplify=True)[0]
if any(iszerofunc(ok[j, j]) for j in range(ok.rows)):
raise ValueError("Matrix det == 0; not invertible.")
return self.LUsolve(self.eye(self.rows), iszerofunc=_iszero)
def inv(self, method=None, **kwargs):
"""
Return the inverse of a matrix.
CASE 1: If the matrix is a dense matrix.
Return the matrix inverse using the method indicated (default
is Gauss elimination).
Parameters
==========
method : ('GE', 'LU', or 'ADJ')
Notes
=====
According to the ``method`` keyword, it calls the appropriate method:
GE .... inverse_GE(); default
LU .... inverse_LU()
ADJ ... inverse_ADJ()
See Also
========
inverse_LU
inverse_GE
inverse_ADJ
Raises
------
ValueError
If the determinant of the matrix is zero.
CASE 2: If the matrix is a sparse matrix.
Return the matrix inverse using Cholesky or LDL (default).
kwargs
======
method : ('CH', 'LDL')
Notes
=====
According to the ``method`` keyword, it calls the appropriate method:
LDL ... inverse_LDL(); default
CH .... inverse_CH()
Raises
------
ValueError
If the determinant of the matrix is zero.
"""
if not self.is_square:
raise NonSquareMatrixError()
if method is not None:
kwargs['method'] = method
return self._eval_inverse(**kwargs)
def is_nilpotent(self):
"""Checks if a matrix is nilpotent.
A matrix B is nilpotent if for some integer k, B**k is
a zero matrix.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[0, 0, 0], [1, 0, 0], [1, 1, 0]])
>>> a.is_nilpotent()
True
>>> a = Matrix([[1, 0, 1], [1, 0, 0], [1, 1, 0]])
>>> a.is_nilpotent()
False
"""
if not self:
return True
if not self.is_square:
raise NonSquareMatrixError(
"Nilpotency is valid only for square matrices")
x = _uniquely_named_symbol('x', self)
p = self.charpoly(x)
if p.args[0] == x ** self.rows:
return True
return False
def key2bounds(self, keys):
"""Converts a key with potentially mixed types of keys (integer and slice)
into a tuple of ranges and raises an error if any index is out of self's
range.
See Also
========
key2ij
"""
from sympy.matrices.common import a2idx as a2idx_ # Remove this line after deprecation of a2idx from matrices.py
islice, jslice = [isinstance(k, slice) for k in keys]
if islice:
if not self.rows:
rlo = rhi = 0
else:
rlo, rhi = keys[0].indices(self.rows)[:2]
else:
rlo = a2idx_(keys[0], self.rows)
rhi = rlo + 1
if jslice:
if not self.cols:
clo = chi = 0
else:
clo, chi = keys[1].indices(self.cols)[:2]
else:
clo = a2idx_(keys[1], self.cols)
chi = clo + 1
return rlo, rhi, clo, chi
def key2ij(self, key):
"""Converts key into canonical form, converting integers or indexable
items into valid integers for self's range or returning slices
unchanged.
See Also
========
key2bounds
"""
from sympy.matrices.common import a2idx as a2idx_ # Remove this line after deprecation of a2idx from matrices.py
if is_sequence(key):
if not len(key) == 2:
raise TypeError('key must be a sequence of length 2')
return [a2idx_(i, n) if not isinstance(i, slice) else i
for i, n in zip(key, self.shape)]
elif isinstance(key, slice):
return key.indices(len(self))[:2]
else:
return divmod(a2idx_(key, len(self)), self.cols)
def LDLdecomposition(self, hermitian=True):
"""Returns the LDL Decomposition (L, D) of matrix A,
such that L * D * L.H == A if hermitian flag is True, or
L * D * L.T == A if hermitian is False.
This method eliminates the use of square root.
Further this ensures that all the diagonal entries of L are 1.
A must be a Hermitian positive-definite matrix if hermitian is True,
or a symmetric matrix otherwise.
Examples
========
>>> from sympy.matrices import Matrix, eye
>>> A = Matrix(((25, 15, -5), (15, 18, 0), (-5, 0, 11)))
>>> L, D = A.LDLdecomposition()
>>> L
Matrix([
[ 1, 0, 0],
[ 3/5, 1, 0],
[-1/5, 1/3, 1]])
>>> D
Matrix([
[25, 0, 0],
[ 0, 9, 0],
[ 0, 0, 9]])
>>> L * D * L.T * A.inv() == eye(A.rows)
True
The matrix can have complex entries:
>>> from sympy import I
>>> A = Matrix(((9, 3*I), (-3*I, 5)))
>>> L, D = A.LDLdecomposition()
>>> L
Matrix([
[ 1, 0],
[-I/3, 1]])
>>> D
Matrix([
[9, 0],
[0, 4]])
>>> L*D*L.H == A
True
See Also
========
cholesky
LUdecomposition
QRdecomposition
"""
if not self.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if hermitian and not self.is_hermitian:
raise ValueError("Matrix must be Hermitian.")
if not hermitian and not self.is_symmetric():
raise ValueError("Matrix must be symmetric.")
return self._LDLdecomposition(hermitian=hermitian)
def LDLsolve(self, rhs):
"""Solves Ax = B using LDL decomposition,
for a general square and non-singular matrix.
For a non-square matrix with rows > cols,
the least squares solution is returned.
Examples
========
>>> from sympy.matrices import Matrix, eye
>>> A = eye(2)*2
>>> B = Matrix([[1, 2], [3, 4]])
>>> A.LDLsolve(B) == B/2
True
See Also
========
LDLdecomposition
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LUsolve
QRsolve
pinv_solve
"""
hermitian = True
if self.is_symmetric():
hermitian = False
L, D = self.LDLdecomposition(hermitian=hermitian)
elif self.is_hermitian:
L, D = self.LDLdecomposition(hermitian=hermitian)
elif self.rows >= self.cols:
L, D = (self.H * self).LDLdecomposition(hermitian=hermitian)
rhs = self.H * rhs
else:
raise NotImplementedError('Under-determined System. '
'Try M.gauss_jordan_solve(rhs)')
Y = L._lower_triangular_solve(rhs)
Z = D._diagonal_solve(Y)
if hermitian:
return (L.H)._upper_triangular_solve(Z)
else:
return (L.T)._upper_triangular_solve(Z)
def lower_triangular_solve(self, rhs):
"""Solves Ax = B, where A is a lower triangular matrix.
See Also
========
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
"""
if not self.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != self.rows:
raise ShapeError("Matrices size mismatch.")
if not self.is_lower:
raise ValueError("Matrix must be lower triangular.")
return self._lower_triangular_solve(rhs)
def LUdecomposition(self,
iszerofunc=_iszero,
simpfunc=None,
rankcheck=False):
"""Returns (L, U, perm) where L is a lower triangular matrix with unit
diagonal, U is an upper triangular matrix, and perm is a list of row
swap index pairs. If A is the original matrix, then
A = (L*U).permuteBkwd(perm), and the row permutation matrix P such
that P*A = L*U can be computed by P=eye(A.row).permuteFwd(perm).
See documentation for LUCombined for details about the keyword argument
rankcheck, iszerofunc, and simpfunc.
Examples
========
>>> from sympy import Matrix
>>> a = Matrix([[4, 3], [6, 3]])
>>> L, U, _ = a.LUdecomposition()
>>> L
Matrix([
[ 1, 0],
[3/2, 1]])
>>> U
Matrix([
[4, 3],
[0, -3/2]])
See Also
========
cholesky
LDLdecomposition
QRdecomposition
LUdecomposition_Simple
LUdecompositionFF
LUsolve
"""
combined, p = self.LUdecomposition_Simple(iszerofunc=iszerofunc,
simpfunc=simpfunc,
rankcheck=rankcheck)
# L is lower triangular self.rows x self.rows
# U is upper triangular self.rows x self.cols
# L has unit diagonal. For each column in combined, the subcolumn
# below the diagonal of combined is shared by L.
# If L has more columns than combined, then the remaining subcolumns
# below the diagonal of L are zero.
# The upper triangular portion of L and combined are equal.
def entry_L(i, j):
if i < j:
# Super diagonal entry
return S.Zero
elif i == j:
return S.One
elif j < combined.cols:
return combined[i, j]
# Subdiagonal entry of L with no corresponding
# entry in combined
return S.Zero
def entry_U(i, j):
return S.Zero if i > j else combined[i, j]
L = self._new(combined.rows, combined.rows, entry_L)
U = self._new(combined.rows, combined.cols, entry_U)
return L, U, p
def LUdecomposition_Simple(self,
iszerofunc=_iszero,
simpfunc=None,
rankcheck=False):
"""Compute an lu decomposition of m x n matrix A, where P*A = L*U
* L is m x m lower triangular with unit diagonal
* U is m x n upper triangular
* P is an m x m permutation matrix
Returns an m x n matrix lu, and an m element list perm where each
element of perm is a pair of row exchange indices.
The factors L and U are stored in lu as follows:
The subdiagonal elements of L are stored in the subdiagonal elements
of lu, that is lu[i, j] = L[i, j] whenever i > j.
The elements on the diagonal of L are all 1, and are not explicitly
stored.
U is stored in the upper triangular portion of lu, that is
lu[i ,j] = U[i, j] whenever i <= j.
The output matrix can be visualized as:
Matrix([
[u, u, u, u],
[l, u, u, u],
[l, l, u, u],
[l, l, l, u]])
where l represents a subdiagonal entry of the L factor, and u
represents an entry from the upper triangular entry of the U
factor.
perm is a list row swap index pairs such that if A is the original
matrix, then A = (L*U).permuteBkwd(perm), and the row permutation
matrix P such that ``P*A = L*U`` can be computed by
``P=eye(A.row).permuteFwd(perm)``.
The keyword argument rankcheck determines if this function raises a
ValueError when passed a matrix whose rank is strictly less than
min(num rows, num cols). The default behavior is to decompose a rank
deficient matrix. Pass rankcheck=True to raise a
ValueError instead. (This mimics the previous behavior of this function).
The keyword arguments iszerofunc and simpfunc are used by the pivot
search algorithm.
iszerofunc is a callable that returns a boolean indicating if its
input is zero, or None if it cannot make the determination.
simpfunc is a callable that simplifies its input.
The default is simpfunc=None, which indicate that the pivot search
algorithm should not attempt to simplify any candidate pivots.
If simpfunc fails to simplify its input, then it must return its input
instead of a copy.
When a matrix contains symbolic entries, the pivot search algorithm
differs from the case where every entry can be categorized as zero or
nonzero.
The algorithm searches column by column through the submatrix whose
top left entry coincides with the pivot position.
If it exists, the pivot is the first entry in the current search
column that iszerofunc guarantees is nonzero.
If no such candidate exists, then each candidate pivot is simplified
if simpfunc is not None.
The search is repeated, with the difference that a candidate may be
the pivot if ``iszerofunc()`` cannot guarantee that it is nonzero.
In the second search the pivot is the first candidate that
iszerofunc can guarantee is nonzero.
If no such candidate exists, then the pivot is the first candidate
for which iszerofunc returns None.
If no such candidate exists, then the search is repeated in the next
column to the right.
The pivot search algorithm differs from the one in `rref()`, which
relies on ``_find_reasonable_pivot()``.
Future versions of ``LUdecomposition_simple()`` may use
``_find_reasonable_pivot()``.
See Also
========
LUdecomposition
LUdecompositionFF
LUsolve
"""
if rankcheck:
# https://github.com/sympy/sympy/issues/9796
pass
if self.rows == 0 or self.cols == 0:
# Define LU decomposition of a matrix with no entries as a matrix
# of the same dimensions with all zero entries.
return self.zeros(self.rows, self.cols), []
lu = self.as_mutable()
row_swaps = []
pivot_col = 0
for pivot_row in range(0, lu.rows - 1):
# Search for pivot. Prefer entry that iszeropivot determines
# is nonzero, over entry that iszeropivot cannot guarantee
# is zero.
# XXX `_find_reasonable_pivot` uses slow zero testing. Blocked by bug #10279
# Future versions of LUdecomposition_simple can pass iszerofunc and simpfunc
# to _find_reasonable_pivot().
# In pass 3 of _find_reasonable_pivot(), the predicate in `if x.equals(S.Zero):`
# calls sympy.simplify(), and not the simplification function passed in via
# the keyword argument simpfunc.
iszeropivot = True
while pivot_col != self.cols and iszeropivot:
sub_col = (lu[r, pivot_col] for r in range(pivot_row, self.rows))
pivot_row_offset, pivot_value, is_assumed_non_zero, ind_simplified_pairs =\
_find_reasonable_pivot_naive(sub_col, iszerofunc, simpfunc)
iszeropivot = pivot_value is None
if iszeropivot:
# All candidate pivots in this column are zero.
# Proceed to next column.
pivot_col += 1
if rankcheck and pivot_col != pivot_row:
# All entries including and below the pivot position are
# zero, which indicates that the rank of the matrix is
# strictly less than min(num rows, num cols)
# Mimic behavior of previous implementation, by throwing a
# ValueError.
raise ValueError("Rank of matrix is strictly less than"
" number of rows or columns."
" Pass keyword argument"
" rankcheck=False to compute"
" the LU decomposition of this matrix.")
candidate_pivot_row = None if pivot_row_offset is None else pivot_row + pivot_row_offset
if candidate_pivot_row is None and iszeropivot:
# If candidate_pivot_row is None and iszeropivot is True
# after pivot search has completed, then the submatrix
# below and to the right of (pivot_row, pivot_col) is
# all zeros, indicating that Gaussian elimination is
# complete.
return lu, row_swaps
# Update entries simplified during pivot search.
for offset, val in ind_simplified_pairs:
lu[pivot_row + offset, pivot_col] = val
if pivot_row != candidate_pivot_row:
# Row swap book keeping:
# Record which rows were swapped.
# Update stored portion of L factor by multiplying L on the
# left and right with the current permutation.
# Swap rows of U.
row_swaps.append([pivot_row, candidate_pivot_row])
# Update L.
lu[pivot_row, 0:pivot_row], lu[candidate_pivot_row, 0:pivot_row] = \
lu[candidate_pivot_row, 0:pivot_row], lu[pivot_row, 0:pivot_row]
# Swap pivot row of U with candidate pivot row.
lu[pivot_row, pivot_col:lu.cols], lu[candidate_pivot_row, pivot_col:lu.cols] = \
lu[candidate_pivot_row, pivot_col:lu.cols], lu[pivot_row, pivot_col:lu.cols]
# Introduce zeros below the pivot by adding a multiple of the
# pivot row to a row under it, and store the result in the
# row under it.
# Only entries in the target row whose index is greater than
# start_col may be nonzero.
start_col = pivot_col + 1
for row in range(pivot_row + 1, lu.rows):
# Store factors of L in the subcolumn below
# (pivot_row, pivot_row).
lu[row, pivot_row] =\
lu[row, pivot_col]/lu[pivot_row, pivot_col]
# Form the linear combination of the pivot row and the current
# row below the pivot row that zeros the entries below the pivot.
# Employing slicing instead of a loop here raises
# NotImplementedError: Cannot add Zero to MutableSparseMatrix
# in sympy/matrices/tests/test_sparse.py.
# c = pivot_row + 1 if pivot_row == pivot_col else pivot_col
for c in range(start_col, lu.cols):
lu[row, c] = lu[row, c] - lu[row, pivot_row]*lu[pivot_row, c]
if pivot_row != pivot_col:
# matrix rank < min(num rows, num cols),
# so factors of L are not stored directly below the pivot.
# These entries are zero by construction, so don't bother
# computing them.
for row in range(pivot_row + 1, lu.rows):
lu[row, pivot_col] = S.Zero
pivot_col += 1
if pivot_col == lu.cols:
# All candidate pivots are zero implies that Gaussian
# elimination is complete.
return lu, row_swaps
return lu, row_swaps
def LUdecompositionFF(self):
"""Compute a fraction-free LU decomposition.
Returns 4 matrices P, L, D, U such that PA = L D**-1 U.
If the elements of the matrix belong to some integral domain I, then all
elements of L, D and U are guaranteed to belong to I.
**Reference**
- W. Zhou & D.J. Jeffrey, "Fraction-free matrix factors: new forms
for LU and QR factors". Frontiers in Computer Science in China,
Vol 2, no. 1, pp. 67-80, 2008.
See Also
========
LUdecomposition
LUdecomposition_Simple
LUsolve
"""
from sympy.matrices import SparseMatrix
zeros = SparseMatrix.zeros
eye = SparseMatrix.eye
n, m = self.rows, self.cols
U, L, P = self.as_mutable(), eye(n), eye(n)
DD = zeros(n, n)
oldpivot = 1
for k in range(n - 1):
if U[k, k] == 0:
for kpivot in range(k + 1, n):
if U[kpivot, k]:
break
else:
raise ValueError("Matrix is not full rank")
U[k, k:], U[kpivot, k:] = U[kpivot, k:], U[k, k:]
L[k, :k], L[kpivot, :k] = L[kpivot, :k], L[k, :k]
P[k, :], P[kpivot, :] = P[kpivot, :], P[k, :]
L[k, k] = Ukk = U[k, k]
DD[k, k] = oldpivot * Ukk
for i in range(k + 1, n):
L[i, k] = Uik = U[i, k]
for j in range(k + 1, m):
U[i, j] = (Ukk * U[i, j] - U[k, j] * Uik) / oldpivot
U[i, k] = 0
oldpivot = Ukk
DD[n - 1, n - 1] = oldpivot
return P, L, DD, U
def LUsolve(self, rhs, iszerofunc=_iszero):
"""Solve the linear system Ax = rhs for x where A = self.
This is for symbolic matrices, for real or complex ones use
mpmath.lu_solve or mpmath.qr_solve.
See Also
========
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
QRsolve
pinv_solve
LUdecomposition
"""
if rhs.rows != self.rows:
raise ShapeError(
"`self` and `rhs` must have the same number of rows.")
m = self.rows
n = self.cols
if m < n:
raise NotImplementedError("Underdetermined systems not supported.")
A, perm = self.LUdecomposition_Simple(iszerofunc=_iszero)
b = rhs.permute_rows(perm).as_mutable()
# forward substitution, all diag entries are scaled to 1
for i in range(m):
for j in range(min(i, n)):
scale = A[i, j]
b.zip_row_op(i, j, lambda x, y: x - y * scale)
# consistency check for overdetermined systems
if m > n:
for i in range(n, m):
for j in range(b.cols):
if not iszerofunc(b[i, j]):
raise ValueError("The system is inconsistent.")
b = b[0:n, :] # truncate zero rows if consistent
# backward substitution
for i in range(n - 1, -1, -1):
for j in range(i + 1, n):
scale = A[i, j]
b.zip_row_op(i, j, lambda x, y: x - y * scale)
scale = A[i, i]
b.row_op(i, lambda x, _: x / scale)
return rhs.__class__(b)
def multiply(self, b):
"""Returns self*b
See Also
========
dot
cross
multiply_elementwise
"""
return self * b
def normalized(self, iszerofunc=_iszero):
"""Return the normalized version of ``self``.
Parameters
==========
iszerofunc : Function, optional
A function to determine whether self is a zero vector.
The default ``_iszero`` tests to see if each element is
exactly zero.
Returns
=======
Matrix
Normalized vector form of self.
It has the same length as a unit vector. However, a zero vector
will be returned for a vector with norm 0.
Raises
======
ShapeError
If the matrix is not in a vector form.
See Also
========
norm
"""
if self.rows != 1 and self.cols != 1:
raise ShapeError("A Matrix must be a vector to normalize.")
norm = self.norm()
if iszerofunc(norm):
out = self.zeros(self.rows, self.cols)
else:
out = self.applyfunc(lambda i: i / norm)
return out
def norm(self, ord=None):
"""Return the Norm of a Matrix or Vector.
In the simplest case this is the geometric size of the vector
Other norms can be specified by the ord parameter
===== ============================ ==========================
ord norm for matrices norm for vectors
===== ============================ ==========================
None Frobenius norm 2-norm
'fro' Frobenius norm - does not exist
inf maximum row sum max(abs(x))
-inf -- min(abs(x))
1 maximum column sum as below
-1 -- as below
2 2-norm (largest sing. value) as below
-2 smallest singular value as below
other - does not exist sum(abs(x)**ord)**(1./ord)
===== ============================ ==========================
Examples
========
>>> from sympy import Matrix, Symbol, trigsimp, cos, sin, oo
>>> x = Symbol('x', real=True)
>>> v = Matrix([cos(x), sin(x)])
>>> trigsimp( v.norm() )
1
>>> v.norm(10)
(sin(x)**10 + cos(x)**10)**(1/10)
>>> A = Matrix([[1, 1], [1, 1]])
>>> A.norm(1) # maximum sum of absolute values of A is 2
2
>>> A.norm(2) # Spectral norm (max of |Ax|/|x| under 2-vector-norm)
2
>>> A.norm(-2) # Inverse spectral norm (smallest singular value)
0
>>> A.norm() # Frobenius Norm
2
>>> A.norm(oo) # Infinity Norm
2
>>> Matrix([1, -2]).norm(oo)
2
>>> Matrix([-1, 2]).norm(-oo)
1
See Also
========
normalized
"""
# Row or Column Vector Norms
vals = list(self.values()) or [0]
if self.rows == 1 or self.cols == 1:
if ord == 2 or ord is None: # Common case sqrt(<x, x>)
return sqrt(Add(*(abs(i) ** 2 for i in vals)))
elif ord == 1: # sum(abs(x))
return Add(*(abs(i) for i in vals))
elif ord == S.Infinity: # max(abs(x))
return Max(*[abs(i) for i in vals])
elif ord == S.NegativeInfinity: # min(abs(x))
return Min(*[abs(i) for i in vals])
# Otherwise generalize the 2-norm, Sum(x_i**ord)**(1/ord)
# Note that while useful this is not mathematically a norm
try:
return Pow(Add(*(abs(i) ** ord for i in vals)), S(1) / ord)
except (NotImplementedError, TypeError):
raise ValueError("Expected order to be Number, Symbol, oo")
# Matrix Norms
else:
if ord == 1: # Maximum column sum
m = self.applyfunc(abs)
return Max(*[sum(m.col(i)) for i in range(m.cols)])
elif ord == 2: # Spectral Norm
# Maximum singular value
return Max(*self.singular_values())
elif ord == -2:
# Minimum singular value
return Min(*self.singular_values())
elif ord == S.Infinity: # Infinity Norm - Maximum row sum
m = self.applyfunc(abs)
return Max(*[sum(m.row(i)) for i in range(m.rows)])
elif (ord is None or isinstance(ord,
string_types) and ord.lower() in
['f', 'fro', 'frobenius', 'vector']):
# Reshape as vector and send back to norm function
return self.vec().norm(ord=2)
else:
raise NotImplementedError("Matrix Norms under development")
def pinv_solve(self, B, arbitrary_matrix=None):
"""Solve Ax = B using the Moore-Penrose pseudoinverse.
There may be zero, one, or infinite solutions. If one solution
exists, it will be returned. If infinite solutions exist, one will
be returned based on the value of arbitrary_matrix. If no solutions
exist, the least-squares solution is returned.
Parameters
==========
B : Matrix
The right hand side of the equation to be solved for. Must have
the same number of rows as matrix A.
arbitrary_matrix : Matrix
If the system is underdetermined (e.g. A has more columns than
rows), infinite solutions are possible, in terms of an arbitrary
matrix. This parameter may be set to a specific matrix to use
for that purpose; if so, it must be the same shape as x, with as
many rows as matrix A has columns, and as many columns as matrix
B. If left as None, an appropriate matrix containing dummy
symbols in the form of ``wn_m`` will be used, with n and m being
row and column position of each symbol.
Returns
=======
x : Matrix
The matrix that will satisfy Ax = B. Will have as many rows as
matrix A has columns, and as many columns as matrix B.
Examples
========
>>> from sympy import Matrix
>>> A = Matrix([[1, 2, 3], [4, 5, 6]])
>>> B = Matrix([7, 8])
>>> A.pinv_solve(B)
Matrix([
[ _w0_0/6 - _w1_0/3 + _w2_0/6 - 55/18],
[-_w0_0/3 + 2*_w1_0/3 - _w2_0/3 + 1/9],
[ _w0_0/6 - _w1_0/3 + _w2_0/6 + 59/18]])
>>> A.pinv_solve(B, arbitrary_matrix=Matrix([0, 0, 0]))
Matrix([
[-55/18],
[ 1/9],
[ 59/18]])
See Also
========
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv
Notes
=====
This may return either exact solutions or least squares solutions.
To determine which, check ``A * A.pinv() * B == B``. It will be
True if exact solutions exist, and False if only a least-squares
solution exists. Be aware that the left hand side of that equation
may need to be simplified to correctly compare to the right hand
side.
References
==========
.. [1] https://en.wikipedia.org/wiki/Moore-Penrose_pseudoinverse#Obtaining_all_solutions_of_a_linear_system
"""
from sympy.matrices import eye
A = self
A_pinv = self.pinv()
if arbitrary_matrix is None:
rows, cols = A.cols, B.cols
w = symbols('w:{0}_:{1}'.format(rows, cols), cls=Dummy)
arbitrary_matrix = self.__class__(cols, rows, w).T
return A_pinv * B + (eye(A.cols) - A_pinv * A) * arbitrary_matrix
def pinv(self):
"""Calculate the Moore-Penrose pseudoinverse of the matrix.
The Moore-Penrose pseudoinverse exists and is unique for any matrix.
If the matrix is invertible, the pseudoinverse is the same as the
inverse.
Examples
========
>>> from sympy import Matrix
>>> Matrix([[1, 2, 3], [4, 5, 6]]).pinv()
Matrix([
[-17/18, 4/9],
[ -1/9, 1/9],
[ 13/18, -2/9]])
See Also
========
inv
pinv_solve
References
==========
.. [1] https://en.wikipedia.org/wiki/Moore-Penrose_pseudoinverse
"""
A = self
AH = self.H
# Trivial case: pseudoinverse of all-zero matrix is its transpose.
if A.is_zero:
return AH
try:
if self.rows >= self.cols:
return (AH * A).inv() * AH
else:
return AH * (A * AH).inv()
except ValueError:
# Matrix is not full rank, so A*AH cannot be inverted.
pass
try:
# However, A*AH is Hermitian, so we can diagonalize it.
if self.rows >= self.cols:
P, D = (AH * A).diagonalize(normalize=True)
D_pinv = D.applyfunc(lambda x: 0 if _iszero(x) else 1 / x)
return P * D_pinv * P.H * AH
else:
P, D = (A * AH).diagonalize(normalize=True)
D_pinv = D.applyfunc(lambda x: 0 if _iszero(x) else 1 / x)
return AH * P * D_pinv * P.H
except MatrixError:
raise NotImplementedError('pinv for rank-deficient matrices where diagonalization '
'of A.H*A fails is not supported yet.')
def print_nonzero(self, symb="X"):
"""Shows location of non-zero entries for fast shape lookup.
Examples
========
>>> from sympy.matrices import Matrix, eye
>>> m = Matrix(2, 3, lambda i, j: i*3+j)
>>> m
Matrix([
[0, 1, 2],
[3, 4, 5]])
>>> m.print_nonzero()
[ XX]
[XXX]
>>> m = eye(4)
>>> m.print_nonzero("x")
[x ]
[ x ]
[ x ]
[ x]
"""
s = []
for i in range(self.rows):
line = []
for j in range(self.cols):
if self[i, j] == 0:
line.append(" ")
else:
line.append(str(symb))
s.append("[%s]" % ''.join(line))
print('\n'.join(s))
def project(self, v):
"""Return the projection of ``self`` onto the line containing ``v``.
Examples
========
>>> from sympy import Matrix, S, sqrt
>>> V = Matrix([sqrt(3)/2, S.Half])
>>> x = Matrix([[1, 0]])
>>> V.project(x)
Matrix([[sqrt(3)/2, 0]])
>>> V.project(-x)
Matrix([[sqrt(3)/2, 0]])
"""
return v * (self.dot(v) / v.dot(v))
def QRdecomposition(self):
"""Return Q, R where A = Q*R, Q is orthogonal and R is upper triangular.
Examples
========
This is the example from wikipedia:
>>> from sympy import Matrix
>>> A = Matrix([[12, -51, 4], [6, 167, -68], [-4, 24, -41]])
>>> Q, R = A.QRdecomposition()
>>> Q
Matrix([
[ 6/7, -69/175, -58/175],
[ 3/7, 158/175, 6/175],
[-2/7, 6/35, -33/35]])
>>> R
Matrix([
[14, 21, -14],
[ 0, 175, -70],
[ 0, 0, 35]])
>>> A == Q*R
True
QR factorization of an identity matrix:
>>> A = Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
>>> Q, R = A.QRdecomposition()
>>> Q
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
>>> R
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
========
cholesky
LDLdecomposition
LUdecomposition
QRsolve
"""
cls = self.__class__
mat = self.as_mutable()
n = mat.rows
m = mat.cols
ranked = list()
# Pad with additional rows to make wide matrices square
# nOrig keeps track of original size so zeros can be trimmed from Q
if n < m:
nOrig = n
n = m
mat = mat.col_join(mat.zeros(n - nOrig, m))
else:
nOrig = n
Q, R = mat.zeros(n, m), mat.zeros(m)
for j in range(m): # for each column vector
tmp = mat[:, j] # take original v
for i in range(j):
# subtract the project of mat on new vector
R[i, j] = Q[:, i].dot(mat[:, j])
tmp -= Q[:, i] * R[i, j]
tmp.expand()
# normalize it
R[j, j] = tmp.norm()
if not R[j, j].is_zero:
ranked.append(j)
Q[:, j] = tmp / R[j, j]
if len(ranked) != 0:
return (
cls(Q.extract(range(nOrig), ranked)),
cls(R.extract(ranked, range(R.cols)))
)
else:
# Trivial case handling for zero-rank matrix
# Force Q as matrix containing standard basis vectors
for i in range(Min(nOrig, m)):
Q[i, i] = 1
return (
cls(Q.extract(range(nOrig), range(Min(nOrig, m)))),
cls(R.extract(range(Min(nOrig, m)), range(R.cols)))
)
def QRsolve(self, b):
"""Solve the linear system 'Ax = b'.
'self' is the matrix 'A', the method argument is the vector
'b'. The method returns the solution vector 'x'. If 'b' is a
matrix, the system is solved for each column of 'b' and the
return value is a matrix of the same shape as 'b'.
This method is slower (approximately by a factor of 2) but
more stable for floating-point arithmetic than the LUsolve method.
However, LUsolve usually uses an exact arithmetic, so you don't need
to use QRsolve.
This is mainly for educational purposes and symbolic matrices, for real
(or complex) matrices use mpmath.qr_solve.
See Also
========
lower_triangular_solve
upper_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
pinv_solve
QRdecomposition
"""
Q, R = self.as_mutable().QRdecomposition()
y = Q.T * b
# back substitution to solve R*x = y:
# We build up the result "backwards" in the vector 'x' and reverse it
# only in the end.
x = []
n = R.rows
for j in range(n - 1, -1, -1):
tmp = y[j, :]
for k in range(j + 1, n):
tmp -= R[j, k] * x[n - 1 - k]
x.append(tmp / R[j, j])
return self._new([row._mat for row in reversed(x)])
def solve_least_squares(self, rhs, method='CH'):
"""Return the least-square fit to the data.
Parameters
==========
rhs : Matrix
Vector representing the right hand side of the linear equation.
method : string or boolean, optional
If set to ``'CH'``, ``cholesky_solve`` routine will be used.
If set to ``'QR'``, ``QRsolve`` routine will be used.
If set to ``'PINV'``, ``pinv_solve`` routine will be used.
Otherwise, the conjugate of self will be used to create a system
of equations that is passed to ``solve`` along with the hint
defined by ``method``.
Returns
=======
solutions : Matrix
Vector representing the solution.
Examples
========
>>> from sympy.matrices import Matrix, ones
>>> A = Matrix([1, 2, 3])
>>> B = Matrix([2, 3, 4])
>>> S = Matrix(A.row_join(B))
>>> S
Matrix([
[1, 2],
[2, 3],
[3, 4]])
If each line of S represent coefficients of Ax + By
and x and y are [2, 3] then S*xy is:
>>> r = S*Matrix([2, 3]); r
Matrix([
[ 8],
[13],
[18]])
But let's add 1 to the middle value and then solve for the
least-squares value of xy:
>>> xy = S.solve_least_squares(Matrix([8, 14, 18])); xy
Matrix([
[ 5/3],
[10/3]])
The error is given by S*xy - r:
>>> S*xy - r
Matrix([
[1/3],
[1/3],
[1/3]])
>>> _.norm().n(2)
0.58
If a different xy is used, the norm will be higher:
>>> xy += ones(2, 1)/10
>>> (S*xy - r).norm().n(2)
1.5
"""
if method == 'CH':
return self.cholesky_solve(rhs)
elif method == 'QR':
return self.QRsolve(rhs)
elif method == 'LDL':
return self.LDLsolve(rhs)
elif method == 'PINV':
return self.pinv_solve(rhs)
else:
t = self.H
return (t * self).solve(t * rhs, method=method)
def solve(self, rhs, method='GJ'):
"""Return the unique soln making self*soln = rhs.
If there is not a unique solution then a ValueError will be raised. If `self` is not
square, a ValueError and a different routine for solving the system will be suggested.
When the method is GJ, the Gauss-Jordan elimination will be used. To use a different
method and to compute the solution via the inverse, use a method defined in the
.inv() docstring.
"""
if method == 'GJ':
try:
soln, param = self.gauss_jordan_solve(rhs)
if param:
raise ValueError("Matrix det == 0; not invertible. "
"Try `self.gauss_jordan_solve(rhs)` to obtain a parametric solution.")
except ValueError:
# raise same error as in inv:
self.zeros(1).inv()
return soln
else:
return self.inv(method=method)*rhs
def table(self, printer, rowstart='[', rowend=']', rowsep='\n',
colsep=', ', align='right'):
r"""
String form of Matrix as a table.
``printer`` is the printer to use for on the elements (generally
something like StrPrinter())
``rowstart`` is the string used to start each row (by default '[').
``rowend`` is the string used to end each row (by default ']').
``rowsep`` is the string used to separate rows (by default a newline).
``colsep`` is the string used to separate columns (by default ', ').
``align`` defines how the elements are aligned. Must be one of 'left',
'right', or 'center'. You can also use '<', '>', and '^' to mean the
same thing, respectively.
This is used by the string printer for Matrix.
Examples
========
>>> from sympy import Matrix
>>> from sympy.printing.str import StrPrinter
>>> M = Matrix([[1, 2], [-33, 4]])
>>> printer = StrPrinter()
>>> M.table(printer)
'[ 1, 2]\n[-33, 4]'
>>> print(M.table(printer))
[ 1, 2]
[-33, 4]
>>> print(M.table(printer, rowsep=',\n'))
[ 1, 2],
[-33, 4]
>>> print('[%s]' % M.table(printer, rowsep=',\n'))
[[ 1, 2],
[-33, 4]]
>>> print(M.table(printer, colsep=' '))
[ 1 2]
[-33 4]
>>> print(M.table(printer, align='center'))
[ 1 , 2]
[-33, 4]
>>> print(M.table(printer, rowstart='{', rowend='}'))
{ 1, 2}
{-33, 4}
"""
# Handle zero dimensions:
if self.rows == 0 or self.cols == 0:
return '[]'
# Build table of string representations of the elements
res = []
# Track per-column max lengths for pretty alignment
maxlen = [0] * self.cols
for i in range(self.rows):
res.append([])
for j in range(self.cols):
s = printer._print(self[i, j])
res[-1].append(s)
maxlen[j] = max(len(s), maxlen[j])
# Patch strings together
align = {
'left': 'ljust',
'right': 'rjust',
'center': 'center',
'<': 'ljust',
'>': 'rjust',
'^': 'center',
}[align]
for i, row in enumerate(res):
for j, elem in enumerate(row):
row[j] = getattr(elem, align)(maxlen[j])
res[i] = rowstart + colsep.join(row) + rowend
return rowsep.join(res)
def upper_triangular_solve(self, rhs):
"""Solves Ax = B, where A is an upper triangular matrix.
See Also
========
lower_triangular_solve
gauss_jordan_solve
cholesky_solve
diagonal_solve
LDLsolve
LUsolve
QRsolve
pinv_solve
"""
if not self.is_square:
raise NonSquareMatrixError("Matrix must be square.")
if rhs.rows != self.rows:
raise TypeError("Matrix size mismatch.")
if not self.is_upper:
raise TypeError("Matrix is not upper triangular.")
return self._upper_triangular_solve(rhs)
def vech(self, diagonal=True, check_symmetry=True):
"""Return the unique elements of a symmetric Matrix as a one column matrix
by stacking the elements in the lower triangle.
Arguments:
diagonal -- include the diagonal cells of self or not
check_symmetry -- checks symmetry of self but not completely reliably
Examples
========
>>> from sympy import Matrix
>>> m=Matrix([[1, 2], [2, 3]])
>>> m
Matrix([
[1, 2],
[2, 3]])
>>> m.vech()
Matrix([
[1],
[2],
[3]])
>>> m.vech(diagonal=False)
Matrix([[2]])
See Also
========
vec
"""
from sympy.matrices import zeros
c = self.cols
if c != self.rows:
raise ShapeError("Matrix must be square")
if check_symmetry:
self.simplify()
if self != self.transpose():
raise ValueError(
"Matrix appears to be asymmetric; consider check_symmetry=False")
count = 0
if diagonal:
v = zeros(c * (c + 1) // 2, 1)
for j in range(c):
for i in range(j, c):
v[count] = self[i, j]
count += 1
else:
v = zeros(c * (c - 1) // 2, 1)
for j in range(c):
for i in range(j + 1, c):
v[count] = self[i, j]
count += 1
return v
@deprecated(
issue=15109,
useinstead="from sympy.matrices.common import classof",
deprecated_since_version="1.3")
def classof(A, B):
from sympy.matrices.common import classof as classof_
return classof_(A, B)
@deprecated(
issue=15109,
deprecated_since_version="1.3",
useinstead="from sympy.matrices.common import a2idx")
def a2idx(j, n=None):
from sympy.matrices.common import a2idx as a2idx_
return a2idx_(j, n)
def _find_reasonable_pivot(col, iszerofunc=_iszero, simpfunc=_simplify):
""" Find the lowest index of an item in `col` that is
suitable for a pivot. If `col` consists only of
Floats, the pivot with the largest norm is returned.
Otherwise, the first element where `iszerofunc` returns
False is used. If `iszerofunc` doesn't return false,
items are simplified and retested until a suitable
pivot is found.
Returns a 4-tuple
(pivot_offset, pivot_val, assumed_nonzero, newly_determined)
where pivot_offset is the index of the pivot, pivot_val is
the (possibly simplified) value of the pivot, assumed_nonzero
is True if an assumption that the pivot was non-zero
was made without being proved, and newly_determined are
elements that were simplified during the process of pivot
finding."""
newly_determined = []
col = list(col)
# a column that contains a mix of floats and integers
# but at least one float is considered a numerical
# column, and so we do partial pivoting
if all(isinstance(x, (Float, Integer)) for x in col) and any(
isinstance(x, Float) for x in col):
col_abs = [abs(x) for x in col]
max_value = max(col_abs)
if iszerofunc(max_value):
# just because iszerofunc returned True, doesn't
# mean the value is numerically zero. Make sure
# to replace all entries with numerical zeros
if max_value != 0:
newly_determined = [(i, 0) for i, x in enumerate(col) if x != 0]
return (None, None, False, newly_determined)
index = col_abs.index(max_value)
return (index, col[index], False, newly_determined)
# PASS 1 (iszerofunc directly)
possible_zeros = []
for i, x in enumerate(col):
is_zero = iszerofunc(x)
# is someone wrote a custom iszerofunc, it may return
# BooleanFalse or BooleanTrue instead of True or False,
# so use == for comparison instead of `is`
if is_zero == False:
# we found something that is definitely not zero
return (i, x, False, newly_determined)
possible_zeros.append(is_zero)
# by this point, we've found no certain non-zeros
if all(possible_zeros):
# if everything is definitely zero, we have
# no pivot
return (None, None, False, newly_determined)
# PASS 2 (iszerofunc after simplify)
# we haven't found any for-sure non-zeros, so
# go through the elements iszerofunc couldn't
# make a determination about and opportunistically
# simplify to see if we find something
for i, x in enumerate(col):
if possible_zeros[i] is not None:
continue
simped = simpfunc(x)
is_zero = iszerofunc(simped)
if is_zero == True or is_zero == False:
newly_determined.append((i, simped))
if is_zero == False:
return (i, simped, False, newly_determined)
possible_zeros[i] = is_zero
# after simplifying, some things that were recognized
# as zeros might be zeros
if all(possible_zeros):
# if everything is definitely zero, we have
# no pivot
return (None, None, False, newly_determined)
# PASS 3 (.equals(0))
# some expressions fail to simplify to zero, but
# `.equals(0)` evaluates to True. As a last-ditch
# attempt, apply `.equals` to these expressions
for i, x in enumerate(col):
if possible_zeros[i] is not None:
continue
if x.equals(S.Zero):
# `.iszero` may return False with
# an implicit assumption (e.g., `x.equals(0)`
# when `x` is a symbol), so only treat it
# as proved when `.equals(0)` returns True
possible_zeros[i] = True
newly_determined.append((i, S.Zero))
if all(possible_zeros):
return (None, None, False, newly_determined)
# at this point there is nothing that could definitely
# be a pivot. To maintain compatibility with existing
# behavior, we'll assume that an illdetermined thing is
# non-zero. We should probably raise a warning in this case
i = possible_zeros.index(None)
return (i, col[i], True, newly_determined)
def _find_reasonable_pivot_naive(col, iszerofunc=_iszero, simpfunc=None):
"""
Helper that computes the pivot value and location from a
sequence of contiguous matrix column elements. As a side effect
of the pivot search, this function may simplify some of the elements
of the input column. A list of these simplified entries and their
indices are also returned.
This function mimics the behavior of _find_reasonable_pivot(),
but does less work trying to determine if an indeterminate candidate
pivot simplifies to zero. This more naive approach can be much faster,
with the trade-off that it may erroneously return a pivot that is zero.
`col` is a sequence of contiguous column entries to be searched for
a suitable pivot.
`iszerofunc` is a callable that returns a Boolean that indicates
if its input is zero, or None if no such determination can be made.
`simpfunc` is a callable that simplifies its input. It must return
its input if it does not simplify its input. Passing in
`simpfunc=None` indicates that the pivot search should not attempt
to simplify any candidate pivots.
Returns a 4-tuple:
(pivot_offset, pivot_val, assumed_nonzero, newly_determined)
`pivot_offset` is the sequence index of the pivot.
`pivot_val` is the value of the pivot.
pivot_val and col[pivot_index] are equivalent, but will be different
when col[pivot_index] was simplified during the pivot search.
`assumed_nonzero` is a boolean indicating if the pivot cannot be
guaranteed to be zero. If assumed_nonzero is true, then the pivot
may or may not be non-zero. If assumed_nonzero is false, then
the pivot is non-zero.
`newly_determined` is a list of index-value pairs of pivot candidates
that were simplified during the pivot search.
"""
# indeterminates holds the index-value pairs of each pivot candidate
# that is neither zero or non-zero, as determined by iszerofunc().
# If iszerofunc() indicates that a candidate pivot is guaranteed
# non-zero, or that every candidate pivot is zero then the contents
# of indeterminates are unused.
# Otherwise, the only viable candidate pivots are symbolic.
# In this case, indeterminates will have at least one entry,
# and all but the first entry are ignored when simpfunc is None.
indeterminates = []
for i, col_val in enumerate(col):
col_val_is_zero = iszerofunc(col_val)
if col_val_is_zero == False:
# This pivot candidate is non-zero.
return i, col_val, False, []
elif col_val_is_zero is None:
# The candidate pivot's comparison with zero
# is indeterminate.
indeterminates.append((i, col_val))
if len(indeterminates) == 0:
# All candidate pivots are guaranteed to be zero, i.e. there is
# no pivot.
return None, None, False, []
if simpfunc is None:
# Caller did not pass in a simplification function that might
# determine if an indeterminate pivot candidate is guaranteed
# to be nonzero, so assume the first indeterminate candidate
# is non-zero.
return indeterminates[0][0], indeterminates[0][1], True, []
# newly_determined holds index-value pairs of candidate pivots
# that were simplified during the search for a non-zero pivot.
newly_determined = []
for i, col_val in indeterminates:
tmp_col_val = simpfunc(col_val)
if id(col_val) != id(tmp_col_val):
# simpfunc() simplified this candidate pivot.
newly_determined.append((i, tmp_col_val))
if iszerofunc(tmp_col_val) == False:
# Candidate pivot simplified to a guaranteed non-zero value.
return i, tmp_col_val, False, newly_determined
return indeterminates[0][0], indeterminates[0][1], True, newly_determined
|
981527021350a4442a0b86ba95af3f16bd90c750676577b4d1464a167475b4ef
|
"""Implicit plotting module for SymPy
The module implements a data series called ImplicitSeries which is used by
``Plot`` class to plot implicit plots for different backends. The module,
by default, implements plotting using interval arithmetic. It switches to a
fall back algorithm if the expression cannot be plotted using interval arithmetic.
It is also possible to specify to use the fall back algorithm for all plots.
Boolean combinations of expressions cannot be plotted by the fall back
algorithm.
See Also
========
sympy.plotting.plot
References
==========
- Jeffrey Allen Tupper. Reliable Two-Dimensional Graphing Methods for
Mathematical Formulae with Two Free Variables.
- Jeffrey Allen Tupper. Graphing Equations with Generalized Interval
Arithmetic. Master's thesis. University of Toronto, 1996
"""
from __future__ import print_function, division
from .plot import BaseSeries, Plot
from .experimental_lambdify import experimental_lambdify, vectorized_lambdify
from .intervalmath import interval
from sympy.core.relational import (Equality, GreaterThan, LessThan,
Relational, StrictLessThan, StrictGreaterThan)
from sympy import Eq, Tuple, sympify, Symbol, Dummy
from sympy.external import import_module
from sympy.logic.boolalg import BooleanFunction
from sympy.polys.polyutils import _sort_gens
from sympy.utilities.decorator import doctest_depends_on
from sympy.utilities.iterables import flatten
import warnings
class ImplicitSeries(BaseSeries):
""" Representation for Implicit plot """
is_implicit = True
def __init__(self, expr, var_start_end_x, var_start_end_y,
has_equality, use_interval_math, depth, nb_of_points,
line_color):
super(ImplicitSeries, self).__init__()
self.expr = sympify(expr)
self.var_x = sympify(var_start_end_x[0])
self.start_x = float(var_start_end_x[1])
self.end_x = float(var_start_end_x[2])
self.var_y = sympify(var_start_end_y[0])
self.start_y = float(var_start_end_y[1])
self.end_y = float(var_start_end_y[2])
self.get_points = self.get_raster
self.has_equality = has_equality # If the expression has equality, i.e.
#Eq, Greaterthan, LessThan.
self.nb_of_points = nb_of_points
self.use_interval_math = use_interval_math
self.depth = 4 + depth
self.line_color = line_color
def __str__(self):
return ('Implicit equation: %s for '
'%s over %s and %s over %s') % (
str(self.expr),
str(self.var_x),
str((self.start_x, self.end_x)),
str(self.var_y),
str((self.start_y, self.end_y)))
def get_raster(self):
func = experimental_lambdify((self.var_x, self.var_y), self.expr,
use_interval=True)
xinterval = interval(self.start_x, self.end_x)
yinterval = interval(self.start_y, self.end_y)
try:
temp = func(xinterval, yinterval)
except AttributeError:
if self.use_interval_math:
warnings.warn("Adaptive meshing could not be applied to the"
" expression. Using uniform meshing.")
self.use_interval_math = False
if self.use_interval_math:
return self._get_raster_interval(func)
else:
return self._get_meshes_grid()
def _get_raster_interval(self, func):
""" Uses interval math to adaptively mesh and obtain the plot"""
k = self.depth
interval_list = []
#Create initial 32 divisions
np = import_module('numpy')
xsample = np.linspace(self.start_x, self.end_x, 33)
ysample = np.linspace(self.start_y, self.end_y, 33)
#Add a small jitter so that there are no false positives for equality.
# Ex: y==x becomes True for x interval(1, 2) and y interval(1, 2)
#which will draw a rectangle.
jitterx = (np.random.rand(
len(xsample)) * 2 - 1) * (self.end_x - self.start_x) / 2**20
jittery = (np.random.rand(
len(ysample)) * 2 - 1) * (self.end_y - self.start_y) / 2**20
xsample += jitterx
ysample += jittery
xinter = [interval(x1, x2) for x1, x2 in zip(xsample[:-1],
xsample[1:])]
yinter = [interval(y1, y2) for y1, y2 in zip(ysample[:-1],
ysample[1:])]
interval_list = [[x, y] for x in xinter for y in yinter]
plot_list = []
#recursive call refinepixels which subdivides the intervals which are
#neither True nor False according to the expression.
def refine_pixels(interval_list):
""" Evaluates the intervals and subdivides the interval if the
expression is partially satisfied."""
temp_interval_list = []
plot_list = []
for intervals in interval_list:
#Convert the array indices to x and y values
intervalx = intervals[0]
intervaly = intervals[1]
func_eval = func(intervalx, intervaly)
#The expression is valid in the interval. Change the contour
#array values to 1.
if func_eval[1] is False or func_eval[0] is False:
pass
elif func_eval == (True, True):
plot_list.append([intervalx, intervaly])
elif func_eval[1] is None or func_eval[0] is None:
#Subdivide
avgx = intervalx.mid
avgy = intervaly.mid
a = interval(intervalx.start, avgx)
b = interval(avgx, intervalx.end)
c = interval(intervaly.start, avgy)
d = interval(avgy, intervaly.end)
temp_interval_list.append([a, c])
temp_interval_list.append([a, d])
temp_interval_list.append([b, c])
temp_interval_list.append([b, d])
return temp_interval_list, plot_list
while k >= 0 and len(interval_list):
interval_list, plot_list_temp = refine_pixels(interval_list)
plot_list.extend(plot_list_temp)
k = k - 1
#Check whether the expression represents an equality
#If it represents an equality, then none of the intervals
#would have satisfied the expression due to floating point
#differences. Add all the undecided values to the plot.
if self.has_equality:
for intervals in interval_list:
intervalx = intervals[0]
intervaly = intervals[1]
func_eval = func(intervalx, intervaly)
if func_eval[1] and func_eval[0] is not False:
plot_list.append([intervalx, intervaly])
return plot_list, 'fill'
def _get_meshes_grid(self):
"""Generates the mesh for generating a contour.
In the case of equality, ``contour`` function of matplotlib can
be used. In other cases, matplotlib's ``contourf`` is used.
"""
equal = False
if isinstance(self.expr, Equality):
expr = self.expr.lhs - self.expr.rhs
equal = True
elif isinstance(self.expr, (GreaterThan, StrictGreaterThan)):
expr = self.expr.lhs - self.expr.rhs
elif isinstance(self.expr, (LessThan, StrictLessThan)):
expr = self.expr.rhs - self.expr.lhs
else:
raise NotImplementedError("The expression is not supported for "
"plotting in uniform meshed plot.")
np = import_module('numpy')
xarray = np.linspace(self.start_x, self.end_x, self.nb_of_points)
yarray = np.linspace(self.start_y, self.end_y, self.nb_of_points)
x_grid, y_grid = np.meshgrid(xarray, yarray)
func = vectorized_lambdify((self.var_x, self.var_y), expr)
z_grid = func(x_grid, y_grid)
z_grid[np.ma.where(z_grid < 0)] = -1
z_grid[np.ma.where(z_grid > 0)] = 1
if equal:
return xarray, yarray, z_grid, 'contour'
else:
return xarray, yarray, z_grid, 'contourf'
@doctest_depends_on(modules=('matplotlib',))
def plot_implicit(expr, x_var=None, y_var=None, adaptive=True, depth=0,
points=300, line_color="blue", show=True, **kwargs):
"""A plot function to plot implicit equations / inequalities.
Arguments
=========
- ``expr`` : The equation / inequality that is to be plotted.
- ``x_var`` (optional) : symbol to plot on x-axis or tuple giving symbol
and range as ``(symbol, xmin, xmax)``
- ``y_var`` (optional) : symbol to plot on y-axis or tuple giving symbol
and range as ``(symbol, ymin, ymax)``
If neither ``x_var`` nor ``y_var`` are given then the free symbols in the
expression will be assigned in the order they are sorted.
The following keyword arguments can also be used:
- ``adaptive`` Boolean. The default value is set to True. It has to be
set to False if you want to use a mesh grid.
- ``depth`` integer. The depth of recursion for adaptive mesh grid.
Default value is 0. Takes value in the range (0, 4).
- ``points`` integer. The number of points if adaptive mesh grid is not
used. Default value is 300.
- ``show`` Boolean. Default value is True. If set to False, the plot will
not be shown. See ``Plot`` for further information.
- ``title`` string. The title for the plot.
- ``xlabel`` string. The label for the x-axis
- ``ylabel`` string. The label for the y-axis
Aesthetics options:
- ``line_color``: float or string. Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
Default value is "Blue"
plot_implicit, by default, uses interval arithmetic to plot functions. If
the expression cannot be plotted using interval arithmetic, it defaults to
a generating a contour using a mesh grid of fixed number of points. By
setting adaptive to False, you can force plot_implicit to use the mesh
grid. The mesh grid method can be effective when adaptive plotting using
interval arithmetic, fails to plot with small line width.
Examples
========
Plot expressions:
>>> from sympy import plot_implicit, cos, sin, symbols, Eq, And
>>> x, y = symbols('x y')
Without any ranges for the symbols in the expression
>>> p1 = plot_implicit(Eq(x**2 + y**2, 5))
With the range for the symbols
>>> p2 = plot_implicit(Eq(x**2 + y**2, 3),
... (x, -3, 3), (y, -3, 3))
With depth of recursion as argument.
>>> p3 = plot_implicit(Eq(x**2 + y**2, 5),
... (x, -4, 4), (y, -4, 4), depth = 2)
Using mesh grid and not using adaptive meshing.
>>> p4 = plot_implicit(Eq(x**2 + y**2, 5),
... (x, -5, 5), (y, -2, 2), adaptive=False)
Using mesh grid with number of points as input.
>>> p5 = plot_implicit(Eq(x**2 + y**2, 5),
... (x, -5, 5), (y, -2, 2),
... adaptive=False, points=400)
Plotting regions.
>>> p6 = plot_implicit(y > x**2)
Plotting Using boolean conjunctions.
>>> p7 = plot_implicit(And(y > x, y > -x))
When plotting an expression with a single variable (y - 1, for example),
specify the x or the y variable explicitly:
>>> p8 = plot_implicit(y - 1, y_var=y)
>>> p9 = plot_implicit(x - 1, x_var=x)
"""
has_equality = False # Represents whether the expression contains an Equality,
#GreaterThan or LessThan
def arg_expand(bool_expr):
"""
Recursively expands the arguments of an Boolean Function
"""
for arg in bool_expr.args:
if isinstance(arg, BooleanFunction):
arg_expand(arg)
elif isinstance(arg, Relational):
arg_list.append(arg)
arg_list = []
if isinstance(expr, BooleanFunction):
arg_expand(expr)
#Check whether there is an equality in the expression provided.
if any(isinstance(e, (Equality, GreaterThan, LessThan))
for e in arg_list):
has_equality = True
elif not isinstance(expr, Relational):
expr = Eq(expr, 0)
has_equality = True
elif isinstance(expr, (Equality, GreaterThan, LessThan)):
has_equality = True
xyvar = [i for i in (x_var, y_var) if i is not None]
free_symbols = expr.free_symbols
range_symbols = Tuple(*flatten(xyvar)).free_symbols
undeclared = free_symbols - range_symbols
if len(free_symbols & range_symbols) > 2:
raise NotImplementedError("Implicit plotting is not implemented for "
"more than 2 variables")
#Create default ranges if the range is not provided.
default_range = Tuple(-5, 5)
def _range_tuple(s):
if isinstance(s, Symbol):
return Tuple(s) + default_range
if len(s) == 3:
return Tuple(*s)
raise ValueError('symbol or `(symbol, min, max)` expected but got %s' % s)
if len(xyvar) == 0:
xyvar = list(_sort_gens(free_symbols))
var_start_end_x = _range_tuple(xyvar[0])
x = var_start_end_x[0]
if len(xyvar) != 2:
if x in undeclared or not undeclared:
xyvar.append(Dummy('f(%s)' % x.name))
else:
xyvar.append(undeclared.pop())
var_start_end_y = _range_tuple(xyvar[1])
#Check whether the depth is greater than 4 or less than 0.
if depth > 4:
depth = 4
elif depth < 0:
depth = 0
series_argument = ImplicitSeries(expr, var_start_end_x, var_start_end_y,
has_equality, adaptive, depth,
points, line_color)
#set the x and y limits
kwargs['xlim'] = tuple(float(x) for x in var_start_end_x[1:])
kwargs['ylim'] = tuple(float(y) for y in var_start_end_y[1:])
# set the x and y labels
kwargs.setdefault('xlabel', var_start_end_x[0].name)
kwargs.setdefault('ylabel', var_start_end_y[0].name)
p = Plot(series_argument, **kwargs)
if show:
p.show()
return p
|
a84068fdb8e63a1aedf5b59da1825798b9b50e003625472a8b69c8e33b423efc
|
"""Plotting module for Sympy.
A plot is represented by the ``Plot`` class that contains a reference to the
backend and a list of the data series to be plotted. The data series are
instances of classes meant to simplify getting points and meshes from sympy
expressions. ``plot_backends`` is a dictionary with all the backends.
This module gives only the essential. For all the fancy stuff use directly
the backend. You can get the backend wrapper for every plot from the
``_backend`` attribute. Moreover the data series classes have various useful
methods like ``get_points``, ``get_segments``, ``get_meshes``, etc, that may
be useful if you wish to use another plotting library.
Especially if you need publication ready graphs and this module is not enough
for you - just get the ``_backend`` attribute and add whatever you want
directly to it. In the case of matplotlib (the common way to graph data in
python) just copy ``_backend.fig`` which is the figure and ``_backend.ax``
which is the axis and work on them as you would on any other matplotlib object.
Simplicity of code takes much greater importance than performance. Don't use it
if you care at all about performance. A new backend instance is initialized
every time you call ``show()`` and the old one is left to the garbage collector.
"""
from __future__ import print_function, division
import inspect
import warnings
import sys
from sympy import sympify, Expr, Tuple, Dummy, Symbol
from sympy.external import import_module
from sympy.core.compatibility import range, Callable
from sympy.utilities.iterables import is_sequence
from .experimental_lambdify import (vectorized_lambdify, lambdify)
# N.B.
# When changing the minimum module version for matplotlib, please change
# the same in the `SymPyDocTestFinder`` in `sympy/utilities/runtests.py`
# Backend specific imports - textplot
from sympy.plotting.textplot import textplot
# Global variable
# Set to False when running tests / doctests so that the plots don't show.
_show = True
def unset_show():
"""
Disable show(). For use in the tests.
"""
global _show
_show = False
##############################################################################
# The public interface
##############################################################################
def _arity(f):
"""
Python 2 and 3 compatible version that do not raise a Deprecation warning.
"""
if sys.version_info < (3,):
return len(inspect.getargspec(f)[0])
else:
param = inspect.signature(f).parameters.values()
return len([p for p in param if p.kind == p.POSITIONAL_OR_KEYWORD])
class Plot(object):
"""The central class of the plotting module.
For interactive work the function ``plot`` is better suited.
This class permits the plotting of sympy expressions using numerous
backends (matplotlib, textplot, the old pyglet module for sympy, Google
charts api, etc).
The figure can contain an arbitrary number of plots of sympy expressions,
lists of coordinates of points, etc. Plot has a private attribute _series that
contains all data series to be plotted (expressions for lines or surfaces,
lists of points, etc (all subclasses of BaseSeries)). Those data series are
instances of classes not imported by ``from sympy import *``.
The customization of the figure is on two levels. Global options that
concern the figure as a whole (eg title, xlabel, scale, etc) and
per-data series options (eg name) and aesthetics (eg. color, point shape,
line type, etc.).
The difference between options and aesthetics is that an aesthetic can be
a function of the coordinates (or parameters in a parametric plot). The
supported values for an aesthetic are:
- None (the backend uses default values)
- a constant
- a function of one variable (the first coordinate or parameter)
- a function of two variables (the first and second coordinate or
parameters)
- a function of three variables (only in nonparametric 3D plots)
Their implementation depends on the backend so they may not work in some
backends.
If the plot is parametric and the arity of the aesthetic function permits
it the aesthetic is calculated over parameters and not over coordinates.
If the arity does not permit calculation over parameters the calculation is
done over coordinates.
Only cartesian coordinates are supported for the moment, but you can use
the parametric plots to plot in polar, spherical and cylindrical
coordinates.
The arguments for the constructor Plot must be subclasses of BaseSeries.
Any global option can be specified as a keyword argument.
The global options for a figure are:
- title : str
- xlabel : str
- ylabel : str
- legend : bool
- xscale : {'linear', 'log'}
- yscale : {'linear', 'log'}
- axis : bool
- axis_center : tuple of two floats or {'center', 'auto'}
- xlim : tuple of two floats
- ylim : tuple of two floats
- aspect_ratio : tuple of two floats or {'auto'}
- autoscale : bool
- margin : float in [0, 1]
The per data series options and aesthetics are:
There are none in the base series. See below for options for subclasses.
Some data series support additional aesthetics or options:
ListSeries, LineOver1DRangeSeries, Parametric2DLineSeries,
Parametric3DLineSeries support the following:
Aesthetics:
- line_color : function which returns a float.
options:
- label : str
- steps : bool
- integers_only : bool
SurfaceOver2DRangeSeries, ParametricSurfaceSeries support the following:
aesthetics:
- surface_color : function which returns a float.
"""
def __init__(self, *args, **kwargs):
super(Plot, self).__init__()
# Options for the graph as a whole.
# The possible values for each option are described in the docstring of
# Plot. They are based purely on convention, no checking is done.
self.title = None
self.xlabel = None
self.ylabel = None
self.aspect_ratio = 'auto'
self.xlim = None
self.ylim = None
self.axis_center = 'auto'
self.axis = True
self.xscale = 'linear'
self.yscale = 'linear'
self.legend = False
self.autoscale = True
self.margin = 0
# Contains the data objects to be plotted. The backend should be smart
# enough to iterate over this list.
self._series = []
self._series.extend(args)
# The backend type. On every show() a new backend instance is created
# in self._backend which is tightly coupled to the Plot instance
# (thanks to the parent attribute of the backend).
self.backend = DefaultBackend
# The keyword arguments should only contain options for the plot.
for key, val in kwargs.items():
if hasattr(self, key):
setattr(self, key, val)
def show(self):
# TODO move this to the backend (also for save)
if hasattr(self, '_backend'):
self._backend.close()
self._backend = self.backend(self)
self._backend.show()
def save(self, path):
if hasattr(self, '_backend'):
self._backend.close()
self._backend = self.backend(self)
self._backend.save(path)
def __str__(self):
series_strs = [('[%d]: ' % i) + str(s)
for i, s in enumerate(self._series)]
return 'Plot object containing:\n' + '\n'.join(series_strs)
def __getitem__(self, index):
return self._series[index]
def __setitem__(self, index, *args):
if len(args) == 1 and isinstance(args[0], BaseSeries):
self._series[index] = args
def __delitem__(self, index):
del self._series[index]
def append(self, arg):
"""Adds an element from a plot's series to an existing plot.
Examples
========
Consider two ``Plot`` objects, ``p1`` and ``p2``. To add the
second plot's first series object to the first, use the
``append`` method, like so:
.. plot::
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
>>> p1 = plot(x*x, show=False)
>>> p2 = plot(x, show=False)
>>> p1.append(p2[0])
>>> p1
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
[1]: cartesian line: x for x over (-10.0, 10.0)
>>> p1.show()
See Also
========
extend
"""
if isinstance(arg, BaseSeries):
self._series.append(arg)
else:
raise TypeError('Must specify element of plot to append.')
def extend(self, arg):
"""Adds all series from another plot.
Examples
========
Consider two ``Plot`` objects, ``p1`` and ``p2``. To add the
second plot to the first, use the ``extend`` method, like so:
.. plot::
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
>>> p1 = plot(x**2, show=False)
>>> p2 = plot(x, -x, show=False)
>>> p1.extend(p2)
>>> p1
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
[1]: cartesian line: x for x over (-10.0, 10.0)
[2]: cartesian line: -x for x over (-10.0, 10.0)
>>> p1.show()
"""
if isinstance(arg, Plot):
self._series.extend(arg._series)
elif is_sequence(arg):
self._series.extend(arg)
else:
raise TypeError('Expecting Plot or sequence of BaseSeries')
##############################################################################
# Data Series
##############################################################################
#TODO more general way to calculate aesthetics (see get_color_array)
### The base class for all series
class BaseSeries(object):
"""Base class for the data objects containing stuff to be plotted.
The backend should check if it supports the data series that it's given.
(eg TextBackend supports only LineOver1DRange).
It's the backend responsibility to know how to use the class of
data series that it's given.
Some data series classes are grouped (using a class attribute like is_2Dline)
according to the api they present (based only on convention). The backend is
not obliged to use that api (eg. The LineOver1DRange belongs to the
is_2Dline group and presents the get_points method, but the
TextBackend does not use the get_points method).
"""
# Some flags follow. The rationale for using flags instead of checking base
# classes is that setting multiple flags is simpler than multiple
# inheritance.
is_2Dline = False
# Some of the backends expect:
# - get_points returning 1D np.arrays list_x, list_y
# - get_segments returning np.array (done in Line2DBaseSeries)
# - get_color_array returning 1D np.array (done in Line2DBaseSeries)
# with the colors calculated at the points from get_points
is_3Dline = False
# Some of the backends expect:
# - get_points returning 1D np.arrays list_x, list_y, list_y
# - get_segments returning np.array (done in Line2DBaseSeries)
# - get_color_array returning 1D np.array (done in Line2DBaseSeries)
# with the colors calculated at the points from get_points
is_3Dsurface = False
# Some of the backends expect:
# - get_meshes returning mesh_x, mesh_y, mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
is_contour = False
# Some of the backends expect:
# - get_meshes returning mesh_x, mesh_y, mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
is_implicit = False
# Some of the backends expect:
# - get_meshes returning mesh_x (1D array), mesh_y(1D array,
# mesh_z (2D np.arrays)
# - get_points an alias for get_meshes
#Different from is_contour as the colormap in backend will be
#different
is_parametric = False
# The calculation of aesthetics expects:
# - get_parameter_points returning one or two np.arrays (1D or 2D)
# used for calculation aesthetics
def __init__(self):
super(BaseSeries, self).__init__()
@property
def is_3D(self):
flags3D = [
self.is_3Dline,
self.is_3Dsurface
]
return any(flags3D)
@property
def is_line(self):
flagslines = [
self.is_2Dline,
self.is_3Dline
]
return any(flagslines)
### 2D lines
class Line2DBaseSeries(BaseSeries):
"""A base class for 2D lines.
- adding the label, steps and only_integers options
- making is_2Dline true
- defining get_segments and get_color_array
"""
is_2Dline = True
_dim = 2
def __init__(self):
super(Line2DBaseSeries, self).__init__()
self.label = None
self.steps = False
self.only_integers = False
self.line_color = None
def get_segments(self):
np = import_module('numpy')
points = self.get_points()
if self.steps is True:
x = np.array((points[0], points[0])).T.flatten()[1:]
y = np.array((points[1], points[1])).T.flatten()[:-1]
points = (x, y)
points = np.ma.array(points).T.reshape(-1, 1, self._dim)
return np.ma.concatenate([points[:-1], points[1:]], axis=1)
def get_color_array(self):
np = import_module('numpy')
c = self.line_color
if hasattr(c, '__call__'):
f = np.vectorize(c)
arity = _arity(c)
if arity == 1 and self.is_parametric:
x = self.get_parameter_points()
return f(centers_of_segments(x))
else:
variables = list(map(centers_of_segments, self.get_points()))
if arity == 1:
return f(variables[0])
elif arity == 2:
return f(*variables[:2])
else: # only if the line is 3D (otherwise raises an error)
return f(*variables)
else:
return c*np.ones(self.nb_of_points)
class List2DSeries(Line2DBaseSeries):
"""Representation for a line consisting of list of points."""
def __init__(self, list_x, list_y):
np = import_module('numpy')
super(List2DSeries, self).__init__()
self.list_x = np.array(list_x)
self.list_y = np.array(list_y)
self.label = 'list'
def __str__(self):
return 'list plot'
def get_points(self):
return (self.list_x, self.list_y)
class LineOver1DRangeSeries(Line2DBaseSeries):
"""Representation for a line consisting of a SymPy expression over a range."""
def __init__(self, expr, var_start_end, **kwargs):
super(LineOver1DRangeSeries, self).__init__()
self.expr = sympify(expr)
self.label = str(self.expr)
self.var = sympify(var_start_end[0])
self.start = float(var_start_end[1])
self.end = float(var_start_end[2])
self.nb_of_points = kwargs.get('nb_of_points', 300)
self.adaptive = kwargs.get('adaptive', True)
self.depth = kwargs.get('depth', 12)
self.line_color = kwargs.get('line_color', None)
self.xscale=kwargs.get('xscale','linear')
self.flag=0
def __str__(self):
return 'cartesian line: %s for %s over %s' % (
str(self.expr), str(self.var), str((self.start, self.end)))
def get_segments(self):
"""
Adaptively gets segments for plotting.
The adaptive sampling is done by recursively checking if three
points are almost collinear. If they are not collinear, then more
points are added between those points.
References
==========
[1] Adaptive polygonal approximation of parametric curves,
Luiz Henrique de Figueiredo.
"""
if self.only_integers or not self.adaptive:
return super(LineOver1DRangeSeries, self).get_segments()
else:
f = lambdify([self.var], self.expr)
list_segments = []
np=import_module('numpy')
def sample(p, q, depth):
""" Samples recursively if three points are almost collinear.
For depth < 6, points are added irrespective of whether they
satisfy the collinearity condition or not. The maximum depth
allowed is 12.
"""
np = import_module('numpy')
#Randomly sample to avoid aliasing.
random = 0.45 + np.random.rand() * 0.1
xnew = p[0] + random * (q[0] - p[0])
ynew = f(xnew)
new_point = np.array([xnew, ynew])
if self.flag==1:
return
#Maximum depth
if depth > self.depth:
if p[1] is None or q[1] is None:
self.flag=1
return
list_segments.append([p, q])
#Sample irrespective of whether the line is flat till the
#depth of 6. We are not using linspace to avoid aliasing.
elif depth < 6:
sample(p, new_point, depth + 1)
sample(new_point, q, depth + 1)
#Sample ten points if complex values are encountered
#at both ends. If there is a real value in between, then
#sample those points further.
elif p[1] is None and q[1] is None:
if self.xscale is 'log':
xarray = np.logspace(p[0],q[0], 10)
else:
xarray = np.linspace(p[0], q[0], 10)
yarray = list(map(f, xarray))
if any(y is not None for y in yarray):
for i in range(len(yarray) - 1):
if yarray[i] is not None or yarray[i + 1] is not None:
sample([xarray[i], yarray[i]],
[xarray[i + 1], yarray[i + 1]], depth + 1)
#Sample further if one of the end points in None( i.e. a complex
#value) or the three points are not almost collinear.
elif (p[1] is None or q[1] is None or new_point[1] is None
or not flat(p, new_point, q)):
sample(p, new_point, depth + 1)
sample(new_point, q, depth + 1)
else:
list_segments.append([p, q])
if self.xscale is 'log':
self.start=np.log10(self.start)
self.end=np.log10(self.end)
f_start = f(self.start)
f_end = f(self.end)
sample([self.start, f_start], [self.end, f_end], 0)
return list_segments
def get_points(self):
np = import_module('numpy')
if self.only_integers is True:
if self.xscale is 'log':
list_x = np.logspace(int(self.start), int(self.end),
num=int(self.end) - int(self.start) + 1)
else:
list_x = np.linspace(int(self.start), int(self.end),
num=int(self.end) - int(self.start) + 1)
else:
if self.xscale is 'log':
list_x = np.logspace(self.start, self.end, num=self.nb_of_points)
else:
list_x = np.linspace(self.start, self.end, num=self.nb_of_points)
f = vectorized_lambdify([self.var], self.expr)
list_y = f(list_x)
return (list_x, list_y)
class Parametric2DLineSeries(Line2DBaseSeries):
"""Representation for a line consisting of two parametric sympy expressions
over a range."""
is_parametric = True
def __init__(self, expr_x, expr_y, var_start_end, **kwargs):
super(Parametric2DLineSeries, self).__init__()
self.expr_x = sympify(expr_x)
self.expr_y = sympify(expr_y)
self.label = "(%s, %s)" % (str(self.expr_x), str(self.expr_y))
self.var = sympify(var_start_end[0])
self.start = float(var_start_end[1])
self.end = float(var_start_end[2])
self.nb_of_points = kwargs.get('nb_of_points', 300)
self.adaptive = kwargs.get('adaptive', True)
self.depth = kwargs.get('depth', 12)
self.line_color = kwargs.get('line_color', None)
def __str__(self):
return 'parametric cartesian line: (%s, %s) for %s over %s' % (
str(self.expr_x), str(self.expr_y), str(self.var),
str((self.start, self.end)))
def get_parameter_points(self):
np = import_module('numpy')
return np.linspace(self.start, self.end, num=self.nb_of_points)
def get_points(self):
param = self.get_parameter_points()
fx = vectorized_lambdify([self.var], self.expr_x)
fy = vectorized_lambdify([self.var], self.expr_y)
list_x = fx(param)
list_y = fy(param)
return (list_x, list_y)
def get_segments(self):
"""
Adaptively gets segments for plotting.
The adaptive sampling is done by recursively checking if three
points are almost collinear. If they are not collinear, then more
points are added between those points.
References
==========
[1] Adaptive polygonal approximation of parametric curves,
Luiz Henrique de Figueiredo.
"""
if not self.adaptive:
return super(Parametric2DLineSeries, self).get_segments()
f_x = lambdify([self.var], self.expr_x)
f_y = lambdify([self.var], self.expr_y)
list_segments = []
def sample(param_p, param_q, p, q, depth):
""" Samples recursively if three points are almost collinear.
For depth < 6, points are added irrespective of whether they
satisfy the collinearity condition or not. The maximum depth
allowed is 12.
"""
#Randomly sample to avoid aliasing.
np = import_module('numpy')
random = 0.45 + np.random.rand() * 0.1
param_new = param_p + random * (param_q - param_p)
xnew = f_x(param_new)
ynew = f_y(param_new)
new_point = np.array([xnew, ynew])
#Maximum depth
if depth > self.depth:
list_segments.append([p, q])
#Sample irrespective of whether the line is flat till the
#depth of 6. We are not using linspace to avoid aliasing.
elif depth < 6:
sample(param_p, param_new, p, new_point, depth + 1)
sample(param_new, param_q, new_point, q, depth + 1)
#Sample ten points if complex values are encountered
#at both ends. If there is a real value in between, then
#sample those points further.
elif ((p[0] is None and q[1] is None) or
(p[1] is None and q[1] is None)):
param_array = np.linspace(param_p, param_q, 10)
x_array = list(map(f_x, param_array))
y_array = list(map(f_y, param_array))
if any(x is not None and y is not None
for x, y in zip(x_array, y_array)):
for i in range(len(y_array) - 1):
if ((x_array[i] is not None and y_array[i] is not None) or
(x_array[i + 1] is not None and y_array[i + 1] is not None)):
point_a = [x_array[i], y_array[i]]
point_b = [x_array[i + 1], y_array[i + 1]]
sample(param_array[i], param_array[i], point_a,
point_b, depth + 1)
#Sample further if one of the end points in None( ie a complex
#value) or the three points are not almost collinear.
elif (p[0] is None or p[1] is None
or q[1] is None or q[0] is None
or not flat(p, new_point, q)):
sample(param_p, param_new, p, new_point, depth + 1)
sample(param_new, param_q, new_point, q, depth + 1)
else:
list_segments.append([p, q])
f_start_x = f_x(self.start)
f_start_y = f_y(self.start)
start = [f_start_x, f_start_y]
f_end_x = f_x(self.end)
f_end_y = f_y(self.end)
end = [f_end_x, f_end_y]
sample(self.start, self.end, start, end, 0)
return list_segments
### 3D lines
class Line3DBaseSeries(Line2DBaseSeries):
"""A base class for 3D lines.
Most of the stuff is derived from Line2DBaseSeries."""
is_2Dline = False
is_3Dline = True
_dim = 3
def __init__(self):
super(Line3DBaseSeries, self).__init__()
class Parametric3DLineSeries(Line3DBaseSeries):
"""Representation for a 3D line consisting of two parametric sympy
expressions and a range."""
def __init__(self, expr_x, expr_y, expr_z, var_start_end, **kwargs):
super(Parametric3DLineSeries, self).__init__()
self.expr_x = sympify(expr_x)
self.expr_y = sympify(expr_y)
self.expr_z = sympify(expr_z)
self.label = "(%s, %s)" % (str(self.expr_x), str(self.expr_y))
self.var = sympify(var_start_end[0])
self.start = float(var_start_end[1])
self.end = float(var_start_end[2])
self.nb_of_points = kwargs.get('nb_of_points', 300)
self.line_color = kwargs.get('line_color', None)
def __str__(self):
return '3D parametric cartesian line: (%s, %s, %s) for %s over %s' % (
str(self.expr_x), str(self.expr_y), str(self.expr_z),
str(self.var), str((self.start, self.end)))
def get_parameter_points(self):
np = import_module('numpy')
return np.linspace(self.start, self.end, num=self.nb_of_points)
def get_points(self):
param = self.get_parameter_points()
fx = vectorized_lambdify([self.var], self.expr_x)
fy = vectorized_lambdify([self.var], self.expr_y)
fz = vectorized_lambdify([self.var], self.expr_z)
list_x = fx(param)
list_y = fy(param)
list_z = fz(param)
return (list_x, list_y, list_z)
### Surfaces
class SurfaceBaseSeries(BaseSeries):
"""A base class for 3D surfaces."""
is_3Dsurface = True
def __init__(self):
super(SurfaceBaseSeries, self).__init__()
self.surface_color = None
def get_color_array(self):
np = import_module('numpy')
c = self.surface_color
if isinstance(c, Callable):
f = np.vectorize(c)
arity = _arity(c)
if self.is_parametric:
variables = list(map(centers_of_faces, self.get_parameter_meshes()))
if arity == 1:
return f(variables[0])
elif arity == 2:
return f(*variables)
variables = list(map(centers_of_faces, self.get_meshes()))
if arity == 1:
return f(variables[0])
elif arity == 2:
return f(*variables[:2])
else:
return f(*variables)
else:
return c*np.ones(self.nb_of_points)
class SurfaceOver2DRangeSeries(SurfaceBaseSeries):
"""Representation for a 3D surface consisting of a sympy expression and 2D
range."""
def __init__(self, expr, var_start_end_x, var_start_end_y, **kwargs):
super(SurfaceOver2DRangeSeries, self).__init__()
self.expr = sympify(expr)
self.var_x = sympify(var_start_end_x[0])
self.start_x = float(var_start_end_x[1])
self.end_x = float(var_start_end_x[2])
self.var_y = sympify(var_start_end_y[0])
self.start_y = float(var_start_end_y[1])
self.end_y = float(var_start_end_y[2])
self.nb_of_points_x = kwargs.get('nb_of_points_x', 50)
self.nb_of_points_y = kwargs.get('nb_of_points_y', 50)
self.surface_color = kwargs.get('surface_color', None)
def __str__(self):
return ('cartesian surface: %s for'
' %s over %s and %s over %s') % (
str(self.expr),
str(self.var_x),
str((self.start_x, self.end_x)),
str(self.var_y),
str((self.start_y, self.end_y)))
def get_meshes(self):
np = import_module('numpy')
mesh_x, mesh_y = np.meshgrid(np.linspace(self.start_x, self.end_x,
num=self.nb_of_points_x),
np.linspace(self.start_y, self.end_y,
num=self.nb_of_points_y))
f = vectorized_lambdify((self.var_x, self.var_y), self.expr)
return (mesh_x, mesh_y, f(mesh_x, mesh_y))
class ParametricSurfaceSeries(SurfaceBaseSeries):
"""Representation for a 3D surface consisting of three parametric sympy
expressions and a range."""
is_parametric = True
def __init__(
self, expr_x, expr_y, expr_z, var_start_end_u, var_start_end_v,
**kwargs):
super(ParametricSurfaceSeries, self).__init__()
self.expr_x = sympify(expr_x)
self.expr_y = sympify(expr_y)
self.expr_z = sympify(expr_z)
self.var_u = sympify(var_start_end_u[0])
self.start_u = float(var_start_end_u[1])
self.end_u = float(var_start_end_u[2])
self.var_v = sympify(var_start_end_v[0])
self.start_v = float(var_start_end_v[1])
self.end_v = float(var_start_end_v[2])
self.nb_of_points_u = kwargs.get('nb_of_points_u', 50)
self.nb_of_points_v = kwargs.get('nb_of_points_v', 50)
self.surface_color = kwargs.get('surface_color', None)
def __str__(self):
return ('parametric cartesian surface: (%s, %s, %s) for'
' %s over %s and %s over %s') % (
str(self.expr_x),
str(self.expr_y),
str(self.expr_z),
str(self.var_u),
str((self.start_u, self.end_u)),
str(self.var_v),
str((self.start_v, self.end_v)))
def get_parameter_meshes(self):
np = import_module('numpy')
return np.meshgrid(np.linspace(self.start_u, self.end_u,
num=self.nb_of_points_u),
np.linspace(self.start_v, self.end_v,
num=self.nb_of_points_v))
def get_meshes(self):
mesh_u, mesh_v = self.get_parameter_meshes()
fx = vectorized_lambdify((self.var_u, self.var_v), self.expr_x)
fy = vectorized_lambdify((self.var_u, self.var_v), self.expr_y)
fz = vectorized_lambdify((self.var_u, self.var_v), self.expr_z)
return (fx(mesh_u, mesh_v), fy(mesh_u, mesh_v), fz(mesh_u, mesh_v))
### Contours
class ContourSeries(BaseSeries):
"""Representation for a contour plot."""
# The code is mostly repetition of SurfaceOver2DRange.
# Presently used in contour_plot function
is_contour = True
def __init__(self, expr, var_start_end_x, var_start_end_y):
super(ContourSeries, self).__init__()
self.nb_of_points_x = 50
self.nb_of_points_y = 50
self.expr = sympify(expr)
self.var_x = sympify(var_start_end_x[0])
self.start_x = float(var_start_end_x[1])
self.end_x = float(var_start_end_x[2])
self.var_y = sympify(var_start_end_y[0])
self.start_y = float(var_start_end_y[1])
self.end_y = float(var_start_end_y[2])
self.get_points = self.get_meshes
def __str__(self):
return ('contour: %s for '
'%s over %s and %s over %s') % (
str(self.expr),
str(self.var_x),
str((self.start_x, self.end_x)),
str(self.var_y),
str((self.start_y, self.end_y)))
def get_meshes(self):
np = import_module('numpy')
mesh_x, mesh_y = np.meshgrid(np.linspace(self.start_x, self.end_x,
num=self.nb_of_points_x),
np.linspace(self.start_y, self.end_y,
num=self.nb_of_points_y))
f = vectorized_lambdify((self.var_x, self.var_y), self.expr)
return (mesh_x, mesh_y, f(mesh_x, mesh_y))
##############################################################################
# Backends
##############################################################################
class BaseBackend(object):
def __init__(self, parent):
super(BaseBackend, self).__init__()
self.parent = parent
## don't have to check for the success of importing matplotlib in each case;
## we will only be using this backend if we can successfully import matploblib
class MatplotlibBackend(BaseBackend):
def __init__(self, parent):
super(MatplotlibBackend, self).__init__(parent)
are_3D = [s.is_3D for s in self.parent._series]
self.matplotlib = import_module('matplotlib',
__import__kwargs={'fromlist': ['pyplot', 'cm', 'collections']},
min_module_version='1.1.0', catch=(RuntimeError,))
self.plt = self.matplotlib.pyplot
self.cm = self.matplotlib.cm
self.LineCollection = self.matplotlib.collections.LineCollection
if any(are_3D) and not all(are_3D):
raise ValueError('The matplotlib backend can not mix 2D and 3D.')
elif not any(are_3D):
self.fig = self.plt.figure()
self.ax = self.fig.add_subplot(111)
self.ax.spines['left'].set_position('zero')
self.ax.spines['right'].set_color('none')
self.ax.spines['bottom'].set_position('zero')
self.ax.spines['top'].set_color('none')
self.ax.spines['left'].set_smart_bounds(True)
self.ax.spines['bottom'].set_smart_bounds(False)
self.ax.xaxis.set_ticks_position('bottom')
self.ax.yaxis.set_ticks_position('left')
elif all(are_3D):
## mpl_toolkits.mplot3d is necessary for
## projection='3d'
mpl_toolkits = import_module('mpl_toolkits',
__import__kwargs={'fromlist': ['mplot3d']})
self.fig = self.plt.figure()
self.ax = self.fig.add_subplot(111, projection='3d')
def process_series(self):
parent = self.parent
for s in self.parent._series:
# Create the collections
if s.is_2Dline:
collection = self.LineCollection(s.get_segments())
self.ax.add_collection(collection)
elif s.is_contour:
self.ax.contour(*s.get_meshes())
elif s.is_3Dline:
# TODO too complicated, I blame matplotlib
mpl_toolkits = import_module('mpl_toolkits',
__import__kwargs={'fromlist': ['mplot3d']})
art3d = mpl_toolkits.mplot3d.art3d
collection = art3d.Line3DCollection(s.get_segments())
self.ax.add_collection(collection)
x, y, z = s.get_points()
self.ax.set_xlim((min(x), max(x)))
self.ax.set_ylim((min(y), max(y)))
self.ax.set_zlim((min(z), max(z)))
elif s.is_3Dsurface:
x, y, z = s.get_meshes()
collection = self.ax.plot_surface(x, y, z,
cmap=getattr(self.cm, 'viridis', self.cm.jet),
rstride=1, cstride=1, linewidth=0.1)
elif s.is_implicit:
#Smart bounds have to be set to False for implicit plots.
self.ax.spines['left'].set_smart_bounds(False)
self.ax.spines['bottom'].set_smart_bounds(False)
points = s.get_raster()
if len(points) == 2:
#interval math plotting
x, y = _matplotlib_list(points[0])
self.ax.fill(x, y, facecolor=s.line_color, edgecolor='None')
else:
# use contourf or contour depending on whether it is
# an inequality or equality.
#XXX: ``contour`` plots multiple lines. Should be fixed.
ListedColormap = self.matplotlib.colors.ListedColormap
colormap = ListedColormap(["white", s.line_color])
xarray, yarray, zarray, plot_type = points
if plot_type == 'contour':
self.ax.contour(xarray, yarray, zarray, cmap=colormap)
else:
self.ax.contourf(xarray, yarray, zarray, cmap=colormap)
else:
raise ValueError('The matplotlib backend supports only '
'is_2Dline, is_3Dline, is_3Dsurface and '
'is_contour objects.')
# Customise the collections with the corresponding per-series
# options.
if hasattr(s, 'label'):
collection.set_label(s.label)
if s.is_line and s.line_color:
if isinstance(s.line_color, (float, int)) or isinstance(s.line_color, Callable):
color_array = s.get_color_array()
collection.set_array(color_array)
else:
collection.set_color(s.line_color)
if s.is_3Dsurface and s.surface_color:
if self.matplotlib.__version__ < "1.2.0": # TODO in the distant future remove this check
warnings.warn('The version of matplotlib is too old to use surface coloring.')
elif isinstance(s.surface_color, (float, int)) or isinstance(s.surface_color, Callable):
color_array = s.get_color_array()
color_array = color_array.reshape(color_array.size)
collection.set_array(color_array)
else:
collection.set_color(s.surface_color)
# Set global options.
# TODO The 3D stuff
# XXX The order of those is important.
mpl_toolkits = import_module('mpl_toolkits',
__import__kwargs={'fromlist': ['mplot3d']})
Axes3D = mpl_toolkits.mplot3d.Axes3D
if parent.xscale and not isinstance(self.ax, Axes3D):
self.ax.set_xscale(parent.xscale)
if parent.yscale and not isinstance(self.ax, Axes3D):
self.ax.set_yscale(parent.yscale)
if parent.xlim:
from sympy.core.basic import Basic
xlim = parent.xlim
if any(isinstance(i,Basic) and not i.is_real for i in xlim):
raise ValueError(
"All numbers from xlim={} must be real".format(xlim))
if any(isinstance(i,Basic) and not i.is_finite for i in xlim):
raise ValueError(
"All numbers from xlim={} must be finite".format(xlim))
xlim = (float(i) for i in xlim)
self.ax.set_xlim(xlim)
else:
if all(isinstance(s, LineOver1DRangeSeries) for s in parent._series):
starts = [s.start for s in parent._series]
ends = [s.end for s in parent._series]
self.ax.set_xlim(min(starts), max(ends))
if parent.ylim:
from sympy.core.basic import Basic
ylim = parent.ylim
if any(isinstance(i,Basic) and not i.is_real for i in ylim):
raise ValueError(
"All numbers from ylim={} must be real".format(ylim))
if any(isinstance(i,Basic) and not i.is_finite for i in ylim):
raise ValueError(
"All numbers from ylim={} must be finite".format(ylim))
ylim = (float(i) for i in ylim)
self.ax.set_ylim(ylim)
if not isinstance(self.ax, Axes3D) or self.matplotlib.__version__ >= '1.2.0': # XXX in the distant future remove this check
self.ax.set_autoscale_on(parent.autoscale)
if parent.axis_center:
val = parent.axis_center
if isinstance(self.ax, Axes3D):
pass
elif val == 'center':
self.ax.spines['left'].set_position('center')
self.ax.spines['bottom'].set_position('center')
elif val == 'auto':
xl, xh = self.ax.get_xlim()
yl, yh = self.ax.get_ylim()
pos_left = ('data', 0) if xl*xh <= 0 else 'center'
pos_bottom = ('data', 0) if yl*yh <= 0 else 'center'
self.ax.spines['left'].set_position(pos_left)
self.ax.spines['bottom'].set_position(pos_bottom)
else:
self.ax.spines['left'].set_position(('data', val[0]))
self.ax.spines['bottom'].set_position(('data', val[1]))
if not parent.axis:
self.ax.set_axis_off()
if parent.legend:
if self.ax.legend():
self.ax.legend_.set_visible(parent.legend)
if parent.margin:
self.ax.set_xmargin(parent.margin)
self.ax.set_ymargin(parent.margin)
if parent.title:
self.ax.set_title(parent.title)
if parent.xlabel:
self.ax.set_xlabel(parent.xlabel, position=(1, 0))
if parent.ylabel:
self.ax.set_ylabel(parent.ylabel, position=(0, 1))
def show(self):
self.process_series()
#TODO after fixing https://github.com/ipython/ipython/issues/1255
# you can uncomment the next line and remove the pyplot.show() call
#self.fig.show()
if _show:
self.plt.show()
else:
self.close()
def save(self, path):
self.process_series()
self.fig.savefig(path)
def close(self):
self.plt.close(self.fig)
class TextBackend(BaseBackend):
def __init__(self, parent):
super(TextBackend, self).__init__(parent)
def show(self):
if not _show:
return
if len(self.parent._series) != 1:
raise ValueError(
'The TextBackend supports only one graph per Plot.')
elif not isinstance(self.parent._series[0], LineOver1DRangeSeries):
raise ValueError(
'The TextBackend supports only expressions over a 1D range')
else:
ser = self.parent._series[0]
textplot(ser.expr, ser.start, ser.end)
def close(self):
pass
class DefaultBackend(BaseBackend):
def __new__(cls, parent):
matplotlib = import_module('matplotlib', min_module_version='1.1.0', catch=(RuntimeError,))
if matplotlib:
return MatplotlibBackend(parent)
else:
return TextBackend(parent)
plot_backends = {
'matplotlib': MatplotlibBackend,
'text': TextBackend,
'default': DefaultBackend
}
##############################################################################
# Finding the centers of line segments or mesh faces
##############################################################################
def centers_of_segments(array):
np = import_module('numpy')
return np.mean(np.vstack((array[:-1], array[1:])), 0)
def centers_of_faces(array):
np = import_module('numpy')
return np.mean(np.dstack((array[:-1, :-1],
array[1:, :-1],
array[:-1, 1: ],
array[:-1, :-1],
)), 2)
def flat(x, y, z, eps=1e-3):
"""Checks whether three points are almost collinear"""
np = import_module('numpy')
# Workaround plotting piecewise (#8577):
# workaround for `lambdify` in `.experimental_lambdify` fails
# to return numerical values in some cases. Lower-level fix
# in `lambdify` is possible.
vector_a = (x - y).astype(np.float)
vector_b = (z - y).astype(np.float)
dot_product = np.dot(vector_a, vector_b)
vector_a_norm = np.linalg.norm(vector_a)
vector_b_norm = np.linalg.norm(vector_b)
cos_theta = dot_product / (vector_a_norm * vector_b_norm)
return abs(cos_theta + 1) < eps
def _matplotlib_list(interval_list):
"""
Returns lists for matplotlib ``fill`` command from a list of bounding
rectangular intervals
"""
xlist = []
ylist = []
if len(interval_list):
for intervals in interval_list:
intervalx = intervals[0]
intervaly = intervals[1]
xlist.extend([intervalx.start, intervalx.start,
intervalx.end, intervalx.end, None])
ylist.extend([intervaly.start, intervaly.end,
intervaly.end, intervaly.start, None])
else:
#XXX Ugly hack. Matplotlib does not accept empty lists for ``fill``
xlist.extend([None, None, None, None])
ylist.extend([None, None, None, None])
return xlist, ylist
####New API for plotting module ####
# TODO: Add color arrays for plots.
# TODO: Add more plotting options for 3d plots.
# TODO: Adaptive sampling for 3D plots.
def plot(*args, **kwargs):
"""
Plots a function of a single variable and returns an instance of
the ``Plot`` class (also, see the description of the
``show`` keyword argument below).
The plotting uses an adaptive algorithm which samples recursively to
accurately plot the plot. The adaptive algorithm uses a random point near
the midpoint of two points that has to be further sampled. Hence the same
plots can appear slightly different.
Usage
=====
Single Plot
``plot(expr, range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots with same range.
``plot(expr1, expr2, ..., range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot((expr1, range), (expr2, range), ..., **kwargs)``
Range has to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr`` : Expression representing the function of single variable
``range``: (x, 0, 5), A 3-tuple denoting the range of the free variable.
Keyword Arguments
=================
Arguments for ``plot`` function:
``show``: Boolean. The default value is set to ``True``. Set show to
``False`` and the function will not display the plot. The returned
instance of the ``Plot`` class can then be used to save or display
the plot by calling the ``save()`` and ``show()`` methods
respectively.
Arguments for ``LineOver1DRangeSeries`` class:
``adaptive``: Boolean. The default value is set to True. Set adaptive to False and
specify ``nb_of_points`` if uniform sampling is required.
``depth``: int Recursion depth of the adaptive algorithm. A depth of value ``n``
samples a maximum of `2^{n}` points.
``nb_of_points``: int. Used when the ``adaptive`` is set to False. The function
is uniformly sampled at ``nb_of_points`` number of points.
Aesthetics options:
``line_color``: float. Specifies the color for the plot.
See ``Plot`` to see how to set color for the plots.
If there are multiple plots, then the same series series are applied to
all the plots. If you want to set these options separately, you can index
the ``Plot`` object returned and set it.
Arguments for ``Plot`` class:
``title`` : str. Title of the plot. It is set to the latex representation of
the expression, if the plot has only one expression.
``xlabel`` : str. Label for the x-axis.
``ylabel`` : str. Label for the y-axis.
``xscale``: {'linear', 'log'} Sets the scaling of the x-axis.
``yscale``: {'linear', 'log'} Sets the scaling if the y-axis.
``axis_center``: tuple of two floats denoting the coordinates of the center or
{'center', 'auto'}
``xlim`` : tuple of two floats, denoting the x-axis limits.
``ylim`` : tuple of two floats, denoting the y-axis limits.
Examples
========
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot
>>> x = symbols('x')
Single Plot
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x**2, (x, -5, 5))
Plot object containing:
[0]: cartesian line: x**2 for x over (-5.0, 5.0)
Multiple plots with single range.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x, x**2, x**3, (x, -5, 5))
Plot object containing:
[0]: cartesian line: x for x over (-5.0, 5.0)
[1]: cartesian line: x**2 for x over (-5.0, 5.0)
[2]: cartesian line: x**3 for x over (-5.0, 5.0)
Multiple plots with different ranges.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot((x**2, (x, -6, 6)), (x, (x, -5, 5)))
Plot object containing:
[0]: cartesian line: x**2 for x over (-6.0, 6.0)
[1]: cartesian line: x for x over (-5.0, 5.0)
No adaptive sampling.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot(x**2, adaptive=False, nb_of_points=400)
Plot object containing:
[0]: cartesian line: x**2 for x over (-10.0, 10.0)
See Also
========
Plot, LineOver1DRangeSeries.
"""
args = list(map(sympify, args))
free = set()
for a in args:
if isinstance(a, Expr):
free |= a.free_symbols
if len(free) > 1:
raise ValueError(
'The same variable should be used in all '
'univariate expressions being plotted.')
x = free.pop() if free else Symbol('x')
kwargs.setdefault('xlabel', x.name)
kwargs.setdefault('ylabel', 'f(%s)' % x.name)
show = kwargs.pop('show', True)
series = []
plot_expr = check_arguments(args, 1, 1)
series = [LineOver1DRangeSeries(*arg, **kwargs) for arg in plot_expr]
plots = Plot(*series, **kwargs)
if show:
plots.show()
return plots
def plot_parametric(*args, **kwargs):
"""
Plots a 2D parametric plot.
The plotting uses an adaptive algorithm which samples recursively to
accurately plot the plot. The adaptive algorithm uses a random point near
the midpoint of two points that has to be further sampled. Hence the same
plots can appear slightly different.
Usage
=====
Single plot.
``plot_parametric(expr_x, expr_y, range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots with same range.
``plot_parametric((expr1_x, expr1_y), (expr2_x, expr2_y), range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot_parametric((expr_x, expr_y, range), ..., **kwargs)``
Range has to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr_x`` : Expression representing the function along x.
``expr_y`` : Expression representing the function along y.
``range``: (u, 0, 5), A 3-tuple denoting the range of the parameter
variable.
Keyword Arguments
=================
Arguments for ``Parametric2DLineSeries`` class:
``adaptive``: Boolean. The default value is set to True. Set adaptive to
False and specify ``nb_of_points`` if uniform sampling is required.
``depth``: int Recursion depth of the adaptive algorithm. A depth of
value ``n`` samples a maximum of `2^{n}` points.
``nb_of_points``: int. Used when the ``adaptive`` is set to False. The
function is uniformly sampled at ``nb_of_points`` number of points.
Aesthetics
----------
``line_color``: function which returns a float. Specifies the color for the
plot. See ``sympy.plotting.Plot`` for more details.
If there are multiple plots, then the same Series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
``xlabel`` : str. Label for the x-axis.
``ylabel`` : str. Label for the y-axis.
``xscale``: {'linear', 'log'} Sets the scaling of the x-axis.
``yscale``: {'linear', 'log'} Sets the scaling if the y-axis.
``axis_center``: tuple of two floats denoting the coordinates of the center
or {'center', 'auto'}
``xlim`` : tuple of two floats, denoting the x-axis limits.
``ylim`` : tuple of two floats, denoting the y-axis limits.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols, cos, sin
>>> from sympy.plotting import plot_parametric
>>> u = symbols('u')
Single Parametric plot
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric(cos(u), sin(u), (u, -5, 5))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-5.0, 5.0)
Multiple parametric plot with single range.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric((cos(u), sin(u)), (u, cos(u)))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-10.0, 10.0)
[1]: parametric cartesian line: (u, cos(u)) for u over (-10.0, 10.0)
Multiple parametric plots.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot_parametric((cos(u), sin(u), (u, -5, 5)),
... (cos(u), u, (u, -5, 5)))
Plot object containing:
[0]: parametric cartesian line: (cos(u), sin(u)) for u over (-5.0, 5.0)
[1]: parametric cartesian line: (cos(u), u) for u over (-5.0, 5.0)
See Also
========
Plot, Parametric2DLineSeries
"""
args = list(map(sympify, args))
show = kwargs.pop('show', True)
series = []
plot_expr = check_arguments(args, 2, 1)
series = [Parametric2DLineSeries(*arg, **kwargs) for arg in plot_expr]
plots = Plot(*series, **kwargs)
if show:
plots.show()
return plots
def plot3d_parametric_line(*args, **kwargs):
"""
Plots a 3D parametric line plot.
Usage
=====
Single plot:
``plot3d_parametric_line(expr_x, expr_y, expr_z, range, **kwargs)``
If the range is not specified, then a default range of (-10, 10) is used.
Multiple plots.
``plot3d_parametric_line((expr_x, expr_y, expr_z, range), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr_x`` : Expression representing the function along x.
``expr_y`` : Expression representing the function along y.
``expr_z`` : Expression representing the function along z.
``range``: ``(u, 0, 5)``, A 3-tuple denoting the range of the parameter
variable.
Keyword Arguments
=================
Arguments for ``Parametric3DLineSeries`` class.
``nb_of_points``: The range is uniformly sampled at ``nb_of_points``
number of points.
Aesthetics:
``line_color``: function which returns a float. Specifies the color for the
plot. See ``sympy.plotting.Plot`` for more details.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class.
``title`` : str. Title of the plot.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols, cos, sin
>>> from sympy.plotting import plot3d_parametric_line
>>> u = symbols('u')
Single plot.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_line(cos(u), sin(u), u, (u, -5, 5))
Plot object containing:
[0]: 3D parametric cartesian line: (cos(u), sin(u), u) for u over (-5.0, 5.0)
Multiple plots.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_line((cos(u), sin(u), u, (u, -5, 5)),
... (sin(u), u**2, u, (u, -5, 5)))
Plot object containing:
[0]: 3D parametric cartesian line: (cos(u), sin(u), u) for u over (-5.0, 5.0)
[1]: 3D parametric cartesian line: (sin(u), u**2, u) for u over (-5.0, 5.0)
See Also
========
Plot, Parametric3DLineSeries
"""
args = list(map(sympify, args))
show = kwargs.pop('show', True)
series = []
plot_expr = check_arguments(args, 3, 1)
series = [Parametric3DLineSeries(*arg, **kwargs) for arg in plot_expr]
plots = Plot(*series, **kwargs)
if show:
plots.show()
return plots
def plot3d(*args, **kwargs):
"""
Plots a 3D surface plot.
Usage
=====
Single plot
``plot3d(expr, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plot with the same range.
``plot3d(expr1, expr2, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot3d((expr1, range_x, range_y), (expr2, range_x, range_y), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr`` : Expression representing the function along x.
``range_x``: (x, 0, 5), A 3-tuple denoting the range of the x
variable.
``range_y``: (y, 0, 5), A 3-tuple denoting the range of the y
variable.
Keyword Arguments
=================
Arguments for ``SurfaceOver2DRangeSeries`` class:
``nb_of_points_x``: int. The x range is sampled uniformly at
``nb_of_points_x`` of points.
``nb_of_points_y``: int. The y range is sampled uniformly at
``nb_of_points_y`` of points.
Aesthetics:
``surface_color``: Function which returns a float. Specifies the color for
the surface of the plot. See ``sympy.plotting.Plot`` for more details.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
``title`` : str. Title of the plot.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols
>>> from sympy.plotting import plot3d
>>> x, y = symbols('x y')
Single plot
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d(x*y, (x, -5, 5), (y, -5, 5))
Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
Multiple plots with same range
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d(x*y, -x*y, (x, -5, 5), (y, -5, 5))
Plot object containing:
[0]: cartesian surface: x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
[1]: cartesian surface: -x*y for x over (-5.0, 5.0) and y over (-5.0, 5.0)
Multiple plots with different ranges.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d((x**2 + y**2, (x, -5, 5), (y, -5, 5)),
... (x*y, (x, -3, 3), (y, -3, 3)))
Plot object containing:
[0]: cartesian surface: x**2 + y**2 for x over (-5.0, 5.0) and y over (-5.0, 5.0)
[1]: cartesian surface: x*y for x over (-3.0, 3.0) and y over (-3.0, 3.0)
See Also
========
Plot, SurfaceOver2DRangeSeries
"""
args = list(map(sympify, args))
show = kwargs.pop('show', True)
series = []
plot_expr = check_arguments(args, 1, 2)
series = [SurfaceOver2DRangeSeries(*arg, **kwargs) for arg in plot_expr]
plots = Plot(*series, **kwargs)
if show:
plots.show()
return plots
def plot3d_parametric_surface(*args, **kwargs):
"""
Plots a 3D parametric surface plot.
Usage
=====
Single plot.
``plot3d_parametric_surface(expr_x, expr_y, expr_z, range_u, range_v, **kwargs)``
If the ranges is not specified, then a default range of (-10, 10) is used.
Multiple plots.
``plot3d_parametric_surface((expr_x, expr_y, expr_z, range_u, range_v), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr_x``: Expression representing the function along ``x``.
``expr_y``: Expression representing the function along ``y``.
``expr_z``: Expression representing the function along ``z``.
``range_u``: ``(u, 0, 5)``, A 3-tuple denoting the range of the ``u``
variable.
``range_v``: ``(v, 0, 5)``, A 3-tuple denoting the range of the v
variable.
Keyword Arguments
=================
Arguments for ``ParametricSurfaceSeries`` class:
``nb_of_points_u``: int. The ``u`` range is sampled uniformly at
``nb_of_points_v`` of points
``nb_of_points_y``: int. The ``v`` range is sampled uniformly at
``nb_of_points_y`` of points
Aesthetics:
``surface_color``: Function which returns a float. Specifies the color for
the surface of the plot. See ``sympy.plotting.Plot`` for more details.
If there are multiple plots, then the same series arguments are applied for
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
``title`` : str. Title of the plot.
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import symbols, cos, sin
>>> from sympy.plotting import plot3d_parametric_surface
>>> u, v = symbols('u v')
Single plot.
.. plot::
:context: close-figs
:format: doctest
:include-source: True
>>> plot3d_parametric_surface(cos(u + v), sin(u - v), u - v,
... (u, -5, 5), (v, -5, 5))
Plot object containing:
[0]: parametric cartesian surface: (cos(u + v), sin(u - v), u - v) for u over (-5.0, 5.0) and v over (-5.0, 5.0)
See Also
========
Plot, ParametricSurfaceSeries
"""
args = list(map(sympify, args))
show = kwargs.pop('show', True)
series = []
plot_expr = check_arguments(args, 3, 2)
series = [ParametricSurfaceSeries(*arg, **kwargs) for arg in plot_expr]
plots = Plot(*series, **kwargs)
if show:
plots.show()
return plots
def plot_contour(*args, **kwargs):
"""
Draws contour plot of a function
Usage
=====
Single plot
``plot_contour(expr, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plot with the same range.
``plot_contour(expr1, expr2, range_x, range_y, **kwargs)``
If the ranges are not specified, then a default range of (-10, 10) is used.
Multiple plots with different ranges.
``plot_contour((expr1, range_x, range_y), (expr2, range_x, range_y), ..., **kwargs)``
Ranges have to be specified for every expression.
Default range may change in the future if a more advanced default range
detection algorithm is implemented.
Arguments
=========
``expr`` : Expression representing the function along x.
``range_x``: (x, 0, 5), A 3-tuple denoting the range of the x
variable.
``range_y``: (y, 0, 5), A 3-tuple denoting the range of the y
variable.
Keyword Arguments
=================
Arguments for ``ContourSeries`` class:
``nb_of_points_x``: int. The x range is sampled uniformly at
``nb_of_points_x`` of points.
``nb_of_points_y``: int. The y range is sampled uniformly at
``nb_of_points_y`` of points.
Aesthetics:
``surface_color``: Function which returns a float. Specifies the color for
the surface of the plot. See ``sympy.plotting.Plot`` for more details.
If there are multiple plots, then the same series arguments are applied to
all the plots. If you want to set these options separately, you can index
the returned ``Plot`` object and set it.
Arguments for ``Plot`` class:
``title`` : str. Title of the plot.
See Also
========
Plot, ContourSeries
"""
args = list(map(sympify, args))
show = kwargs.pop('show', True)
plot_expr = check_arguments(args, 1, 2)
series = [ContourSeries(*arg) for arg in plot_expr]
plot_contours = Plot(*series, **kwargs)
if len(plot_expr[0].free_symbols) > 2:
raise ValueError('Contour Plot cannot Plot for more than two variables.')
if show:
plot_contours.show()
return plot_contours
def check_arguments(args, expr_len, nb_of_free_symbols):
"""
Checks the arguments and converts into tuples of the
form (exprs, ranges)
Examples
========
.. plot::
:context: reset
:format: doctest
:include-source: True
>>> from sympy import plot, cos, sin, symbols
>>> from sympy.plotting.plot import check_arguments
>>> x = symbols('x')
>>> check_arguments([cos(x), sin(x)], 2, 1)
[(cos(x), sin(x), (x, -10, 10))]
>>> check_arguments([x, x**2], 1, 1)
[(x, (x, -10, 10)), (x**2, (x, -10, 10))]
"""
if expr_len > 1 and isinstance(args[0], Expr):
# Multiple expressions same range.
# The arguments are tuples when the expression length is
# greater than 1.
if len(args) < expr_len:
raise ValueError("len(args) should not be less than expr_len")
for i in range(len(args)):
if isinstance(args[i], Tuple):
break
else:
i = len(args) + 1
exprs = Tuple(*args[:i])
free_symbols = list(set().union(*[e.free_symbols for e in exprs]))
if len(args) == expr_len + nb_of_free_symbols:
#Ranges given
plots = [exprs + Tuple(*args[expr_len:])]
else:
default_range = Tuple(-10, 10)
ranges = []
for symbol in free_symbols:
ranges.append(Tuple(symbol) + default_range)
for i in range(len(free_symbols) - nb_of_free_symbols):
ranges.append(Tuple(Dummy()) + default_range)
plots = [exprs + Tuple(*ranges)]
return plots
if isinstance(args[0], Expr) or (isinstance(args[0], Tuple) and
len(args[0]) == expr_len and
expr_len != 3):
# Cannot handle expressions with number of expression = 3. It is
# not possible to differentiate between expressions and ranges.
#Series of plots with same range
for i in range(len(args)):
if isinstance(args[i], Tuple) and len(args[i]) != expr_len:
break
if not isinstance(args[i], Tuple):
args[i] = Tuple(args[i])
else:
i = len(args) + 1
exprs = args[:i]
assert all(isinstance(e, Expr) for expr in exprs for e in expr)
free_symbols = list(set().union(*[e.free_symbols for expr in exprs
for e in expr]))
if len(free_symbols) > nb_of_free_symbols:
raise ValueError("The number of free_symbols in the expression "
"is greater than %d" % nb_of_free_symbols)
if len(args) == i + nb_of_free_symbols and isinstance(args[i], Tuple):
ranges = Tuple(*[range_expr for range_expr in args[
i:i + nb_of_free_symbols]])
plots = [expr + ranges for expr in exprs]
return plots
else:
#Use default ranges.
default_range = Tuple(-10, 10)
ranges = []
for symbol in free_symbols:
ranges.append(Tuple(symbol) + default_range)
for i in range(nb_of_free_symbols - len(free_symbols)):
ranges.append(Tuple(Dummy()) + default_range)
ranges = Tuple(*ranges)
plots = [expr + ranges for expr in exprs]
return plots
elif isinstance(args[0], Tuple) and len(args[0]) == expr_len + nb_of_free_symbols:
#Multiple plots with different ranges.
for arg in args:
for i in range(expr_len):
if not isinstance(arg[i], Expr):
raise ValueError("Expected an expression, given %s" %
str(arg[i]))
for i in range(nb_of_free_symbols):
if not len(arg[i + expr_len]) == 3:
raise ValueError("The ranges should be a tuple of "
"length 3, got %s" % str(arg[i + expr_len]))
return args
|
6ffb69472bd18ea6a0e6729c496a268bb098ee4ffb2ecc155df17ce5e10122fd
|
from sympy import (Sieve, binomial_coefficients, binomial_coefficients_list,
Mul, S, Pow, sieve, Symbol, summation, Dummy,
factorial as fac)
from sympy.core.evalf import bitcount
from sympy.core.numbers import Integer, Rational
from sympy.core.compatibility import long, range
from sympy.ntheory import (isprime, n_order, is_primitive_root,
is_quad_residue, legendre_symbol, jacobi_symbol, npartitions, totient,
factorint, primefactors, divisors, randprime, nextprime, prevprime,
primerange, primepi, prime, pollard_rho, perfect_power, multiplicity,
trailing, divisor_count, primorial, pollard_pm1, divisor_sigma,
factorrat, reduced_totient)
from sympy.ntheory.factor_ import (smoothness, smoothness_p,
antidivisors, antidivisor_count, core, digits, udivisors, udivisor_sigma,
udivisor_count, primenu, primeomega, small_trailing)
from sympy.ntheory.generate import cycle_length
from sympy.ntheory.multinomial import (
multinomial_coefficients, multinomial_coefficients_iterator)
from sympy.ntheory.bbp_pi import pi_hex_digits
from sympy.ntheory.modular import crt, crt1, crt2, solve_congruence
from sympy.utilities.pytest import raises, slow
from sympy.utilities.iterables import capture
def fac_multiplicity(n, p):
"""Return the power of the prime number p in the
factorization of n!"""
if p > n:
return 0
if p > n//2:
return 1
q, m = n, 0
while q >= p:
q //= p
m += q
return m
def multiproduct(seq=(), start=1):
"""
Return the product of a sequence of factors with multiplicities,
times the value of the parameter ``start``. The input may be a
sequence of (factor, exponent) pairs or a dict of such pairs.
>>> multiproduct({3:7, 2:5}, 4) # = 3**7 * 2**5 * 4
279936
"""
if not seq:
return start
if isinstance(seq, dict):
seq = iter(seq.items())
units = start
multi = []
for base, exp in seq:
if not exp:
continue
elif exp == 1:
units *= base
else:
if exp % 2:
units *= base
multi.append((base, exp//2))
return units * multiproduct(multi)**2
def test_trailing_bitcount():
assert trailing(0) == 0
assert trailing(1) == 0
assert trailing(-1) == 0
assert trailing(2) == 1
assert trailing(7) == 0
assert trailing(-7) == 0
for i in range(100):
assert trailing((1 << i)) == i
assert trailing((1 << i) * 31337) == i
assert trailing((1 << 1000001)) == 1000001
assert trailing((1 << 273956)*7**37) == 273956
# issue 12709
big = small_trailing[-1]*2
assert trailing(-big) == trailing(big)
assert bitcount(-big) == bitcount(big)
def test_multiplicity():
for b in range(2, 20):
for i in range(100):
assert multiplicity(b, b**i) == i
assert multiplicity(b, (b**i) * 23) == i
assert multiplicity(b, (b**i) * 1000249) == i
# Should be fast
assert multiplicity(10, 10**10023) == 10023
# Should exit quickly
assert multiplicity(10**10, 10**10) == 1
# Should raise errors for bad input
raises(ValueError, lambda: multiplicity(1, 1))
raises(ValueError, lambda: multiplicity(1, 2))
raises(ValueError, lambda: multiplicity(1.3, 2))
raises(ValueError, lambda: multiplicity(2, 0))
raises(ValueError, lambda: multiplicity(1.3, 0))
# handles Rationals
assert multiplicity(10, Rational(30, 7)) == 1
assert multiplicity(Rational(2, 7), Rational(4, 7)) == 1
assert multiplicity(Rational(1, 7), Rational(3, 49)) == 2
assert multiplicity(Rational(2, 7), Rational(7, 2)) == -1
assert multiplicity(3, Rational(1, 9)) == -2
def test_perfect_power():
assert perfect_power(0) is False
assert perfect_power(1) is False
assert perfect_power(2) is False
assert perfect_power(3) is False
assert perfect_power(4) == (2, 2)
assert perfect_power(14) is False
assert perfect_power(25) == (5, 2)
assert perfect_power(22) is False
assert perfect_power(22, [2]) is False
assert perfect_power(137**(3*5*13)) == (137, 3*5*13)
assert perfect_power(137**(3*5*13) + 1) is False
assert perfect_power(137**(3*5*13) - 1) is False
assert perfect_power(103005006004**7) == (103005006004, 7)
assert perfect_power(103005006004**7 + 1) is False
assert perfect_power(103005006004**7 - 1) is False
assert perfect_power(103005006004**12) == (103005006004, 12)
assert perfect_power(103005006004**12 + 1) is False
assert perfect_power(103005006004**12 - 1) is False
assert perfect_power(2**10007) == (2, 10007)
assert perfect_power(2**10007 + 1) is False
assert perfect_power(2**10007 - 1) is False
assert perfect_power((9**99 + 1)**60) == (9**99 + 1, 60)
assert perfect_power((9**99 + 1)**60 + 1) is False
assert perfect_power((9**99 + 1)**60 - 1) is False
assert perfect_power((10**40000)**2, big=False) == (10**40000, 2)
assert perfect_power(10**100000) == (10, 100000)
assert perfect_power(10**100001) == (10, 100001)
assert perfect_power(13**4, [3, 5]) is False
assert perfect_power(3**4, [3, 10], factor=0) is False
assert perfect_power(3**3*5**3) == (15, 3)
assert perfect_power(2**3*5**5) is False
assert perfect_power(2*13**4) is False
assert perfect_power(2**5*3**3) is False
def test_factorint():
assert primefactors(123456) == [2, 3, 643]
assert factorint(0) == {0: 1}
assert factorint(1) == {}
assert factorint(-1) == {-1: 1}
assert factorint(-2) == {-1: 1, 2: 1}
assert factorint(-16) == {-1: 1, 2: 4}
assert factorint(2) == {2: 1}
assert factorint(126) == {2: 1, 3: 2, 7: 1}
assert factorint(123456) == {2: 6, 3: 1, 643: 1}
assert factorint(5951757) == {3: 1, 7: 1, 29: 2, 337: 1}
assert factorint(64015937) == {7993: 1, 8009: 1}
assert factorint(2**(2**6) + 1) == {274177: 1, 67280421310721: 1}
assert factorint(0, multiple=True) == [0]
assert factorint(1, multiple=True) == []
assert factorint(-1, multiple=True) == [-1]
assert factorint(-2, multiple=True) == [-1, 2]
assert factorint(-16, multiple=True) == [-1, 2, 2, 2, 2]
assert factorint(2, multiple=True) == [2]
assert factorint(24, multiple=True) == [2, 2, 2, 3]
assert factorint(126, multiple=True) == [2, 3, 3, 7]
assert factorint(123456, multiple=True) == [2, 2, 2, 2, 2, 2, 3, 643]
assert factorint(5951757, multiple=True) == [3, 7, 29, 29, 337]
assert factorint(64015937, multiple=True) == [7993, 8009]
assert factorint(2**(2**6) + 1, multiple=True) == [274177, 67280421310721]
assert factorint(fac(1, evaluate=False)) == {}
assert factorint(fac(7, evaluate=False)) == {2: 4, 3: 2, 5: 1, 7: 1}
assert factorint(fac(15, evaluate=False)) == \
{2: 11, 3: 6, 5: 3, 7: 2, 11: 1, 13: 1}
assert factorint(fac(20, evaluate=False)) == \
{2: 18, 3: 8, 5: 4, 7: 2, 11: 1, 13: 1, 17: 1, 19: 1}
assert factorint(fac(23, evaluate=False)) == \
{2: 19, 3: 9, 5: 4, 7: 3, 11: 2, 13: 1, 17: 1, 19: 1, 23: 1}
assert multiproduct(factorint(fac(200))) == fac(200)
assert multiproduct(factorint(fac(200, evaluate=False))) == fac(200)
for b, e in factorint(fac(150)).items():
assert e == fac_multiplicity(150, b)
for b, e in factorint(fac(150, evaluate=False)).items():
assert e == fac_multiplicity(150, b)
assert factorint(103005006059**7) == {103005006059: 7}
assert factorint(31337**191) == {31337: 191}
assert factorint(2**1000 * 3**500 * 257**127 * 383**60) == \
{2: 1000, 3: 500, 257: 127, 383: 60}
assert len(factorint(fac(10000))) == 1229
assert len(factorint(fac(10000, evaluate=False))) == 1229
assert factorint(12932983746293756928584532764589230) == \
{2: 1, 5: 1, 73: 1, 727719592270351: 1, 63564265087747: 1, 383: 1}
assert factorint(727719592270351) == {727719592270351: 1}
assert factorint(2**64 + 1, use_trial=False) == factorint(2**64 + 1)
for n in range(60000):
assert multiproduct(factorint(n)) == n
assert pollard_rho(2**64 + 1, seed=1) == 274177
assert pollard_rho(19, seed=1) is None
assert factorint(3, limit=2) == {3: 1}
assert factorint(12345) == {3: 1, 5: 1, 823: 1}
assert factorint(
12345, limit=3) == {4115: 1, 3: 1} # the 5 is greater than the limit
assert factorint(1, limit=1) == {}
assert factorint(0, 3) == {0: 1}
assert factorint(12, limit=1) == {12: 1}
assert factorint(30, limit=2) == {2: 1, 15: 1}
assert factorint(16, limit=2) == {2: 4}
assert factorint(124, limit=3) == {2: 2, 31: 1}
assert factorint(4*31**2, limit=3) == {2: 2, 31: 2}
p1 = nextprime(2**32)
p2 = nextprime(2**16)
p3 = nextprime(p2)
assert factorint(p1*p2*p3) == {p1: 1, p2: 1, p3: 1}
assert factorint(13*17*19, limit=15) == {13: 1, 17*19: 1}
assert factorint(1951*15013*15053, limit=2000) == {225990689: 1, 1951: 1}
assert factorint(primorial(17) + 1, use_pm1=0) == \
{long(19026377261): 1, 3467: 1, 277: 1, 105229: 1}
# when prime b is closer than approx sqrt(8*p) to prime p then they are
# "close" and have a trivial factorization
a = nextprime(2**2**8) # 78 digits
b = nextprime(a + 2**2**4)
assert 'Fermat' in capture(lambda: factorint(a*b, verbose=1))
raises(ValueError, lambda: pollard_rho(4))
raises(ValueError, lambda: pollard_pm1(3))
raises(ValueError, lambda: pollard_pm1(10, B=2))
# verbose coverage
n = nextprime(2**16)*nextprime(2**17)*nextprime(1901)
assert 'with primes' in capture(lambda: factorint(n, verbose=1))
capture(lambda: factorint(nextprime(2**16)*1012, verbose=1))
n = nextprime(2**17)
capture(lambda: factorint(n**3, verbose=1)) # perfect power termination
capture(lambda: factorint(2*n, verbose=1)) # factoring complete msg
# exceed 1st
n = nextprime(2**17)
n *= nextprime(n)
assert '1000' in capture(lambda: factorint(n, limit=1000, verbose=1))
n *= nextprime(n)
assert len(factorint(n)) == 3
assert len(factorint(n, limit=p1)) == 3
n *= nextprime(2*n)
# exceed 2nd
assert '2001' in capture(lambda: factorint(n, limit=2000, verbose=1))
assert capture(
lambda: factorint(n, limit=4000, verbose=1)).count('Pollard') == 2
# non-prime pm1 result
n = nextprime(8069)
n *= nextprime(2*n)*nextprime(2*n, 2)
capture(lambda: factorint(n, verbose=1)) # non-prime pm1 result
# factor fermat composite
p1 = nextprime(2**17)
p2 = nextprime(2*p1)
assert factorint((p1*p2**2)**3) == {p1: 3, p2: 6}
# Test for non integer input
raises(ValueError, lambda: factorint(4.5))
def test_divisors_and_divisor_count():
assert divisors(-1) == [1]
assert divisors(0) == []
assert divisors(1) == [1]
assert divisors(2) == [1, 2]
assert divisors(3) == [1, 3]
assert divisors(17) == [1, 17]
assert divisors(10) == [1, 2, 5, 10]
assert divisors(100) == [1, 2, 4, 5, 10, 20, 25, 50, 100]
assert divisors(101) == [1, 101]
assert divisor_count(0) == 0
assert divisor_count(-1) == 1
assert divisor_count(1) == 1
assert divisor_count(6) == 4
assert divisor_count(12) == 6
assert divisor_count(180, 3) == divisor_count(180//3)
assert divisor_count(2*3*5, 7) == 0
def test_udivisors_and_udivisor_count():
assert udivisors(-1) == [1]
assert udivisors(0) == []
assert udivisors(1) == [1]
assert udivisors(2) == [1, 2]
assert udivisors(3) == [1, 3]
assert udivisors(17) == [1, 17]
assert udivisors(10) == [1, 2, 5, 10]
assert udivisors(100) == [1, 4, 25, 100]
assert udivisors(101) == [1, 101]
assert udivisors(1000) == [1, 8, 125, 1000]
assert udivisor_count(0) == 0
assert udivisor_count(-1) == 1
assert udivisor_count(1) == 1
assert udivisor_count(6) == 4
assert udivisor_count(12) == 4
assert udivisor_count(180) == 8
assert udivisor_count(2*3*5*7) == 16
def test_issue_6981():
S = set(divisors(4)).union(set(divisors(Integer(2))))
assert S == {1,2,4}
def test_totient():
assert [totient(k) for k in range(1, 12)] == \
[1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10]
assert totient(5005) == 2880
assert totient(5006) == 2502
assert totient(5009) == 5008
assert totient(2**100) == 2**99
raises(ValueError, lambda: totient(30.1))
raises(ValueError, lambda: totient(20.001))
m = Symbol("m", integer=True)
assert totient(m)
assert totient(m).subs(m, 3**10) == 3**10 - 3**9
assert summation(totient(m), (m, 1, 11)) == 42
n = Symbol("n", integer=True, positive=True)
assert totient(n).is_integer
x=Symbol("x", integer=False)
raises(ValueError, lambda: totient(x))
y=Symbol("y", positive=False)
raises(ValueError, lambda: totient(y))
z=Symbol("z", positive=True, integer=True)
raises(ValueError, lambda: totient(2**(-z)))
def test_reduced_totient():
assert [reduced_totient(k) for k in range(1, 16)] == \
[1, 1, 2, 2, 4, 2, 6, 2, 6, 4, 10, 2, 12, 6, 4]
assert reduced_totient(5005) == 60
assert reduced_totient(5006) == 2502
assert reduced_totient(5009) == 5008
assert reduced_totient(2**100) == 2**98
m = Symbol("m", integer=True)
assert reduced_totient(m)
assert reduced_totient(m).subs(m, 2**3*3**10) == 3**10 - 3**9
assert summation(reduced_totient(m), (m, 1, 16)) == 68
n = Symbol("n", integer=True, positive=True)
assert reduced_totient(n).is_integer
def test_divisor_sigma():
assert [divisor_sigma(k) for k in range(1, 12)] == \
[1, 3, 4, 7, 6, 12, 8, 15, 13, 18, 12]
assert [divisor_sigma(k, 2) for k in range(1, 12)] == \
[1, 5, 10, 21, 26, 50, 50, 85, 91, 130, 122]
assert divisor_sigma(23450) == 50592
assert divisor_sigma(23450, 0) == 24
assert divisor_sigma(23450, 1) == 50592
assert divisor_sigma(23450, 2) == 730747500
assert divisor_sigma(23450, 3) == 14666785333344
m = Symbol("m", integer=True)
k = Symbol("k", integer=True)
assert divisor_sigma(m)
assert divisor_sigma(m, k)
assert divisor_sigma(m).subs(m, 3**10) == 88573
assert divisor_sigma(m, k).subs([(m, 3**10), (k, 3)]) == 213810021790597
assert summation(divisor_sigma(m), (m, 1, 11)) == 99
def test_udivisor_sigma():
assert [udivisor_sigma(k) for k in range(1, 12)] == \
[1, 3, 4, 5, 6, 12, 8, 9, 10, 18, 12]
assert [udivisor_sigma(k, 3) for k in range(1, 12)] == \
[1, 9, 28, 65, 126, 252, 344, 513, 730, 1134, 1332]
assert udivisor_sigma(23450) == 42432
assert udivisor_sigma(23450, 0) == 16
assert udivisor_sigma(23450, 1) == 42432
assert udivisor_sigma(23450, 2) == 702685000
assert udivisor_sigma(23450, 4) == 321426961814978248
m = Symbol("m", integer=True)
k = Symbol("k", integer=True)
assert udivisor_sigma(m)
assert udivisor_sigma(m, k)
assert udivisor_sigma(m).subs(m, 4**9) == 262145
assert udivisor_sigma(m, k).subs([(m, 4**9), (k, 2)]) == 68719476737
assert summation(udivisor_sigma(m), (m, 2, 15)) == 169
def test_issue_4356():
assert factorint(1030903) == {53: 2, 367: 1}
def test_divisors():
assert divisors(28) == [1, 2, 4, 7, 14, 28]
assert [x for x in divisors(3*5*7, 1)] == [1, 3, 5, 15, 7, 21, 35, 105]
assert divisors(0) == []
def test_divisor_count():
assert divisor_count(0) == 0
assert divisor_count(6) == 4
def test_antidivisors():
assert antidivisors(-1) == []
assert antidivisors(-3) == [2]
assert antidivisors(14) == [3, 4, 9]
assert antidivisors(237) == [2, 5, 6, 11, 19, 25, 43, 95, 158]
assert antidivisors(12345) == [2, 6, 7, 10, 30, 1646, 3527, 4938, 8230]
assert antidivisors(393216) == [262144]
assert sorted(x for x in antidivisors(3*5*7, 1)) == \
[2, 6, 10, 11, 14, 19, 30, 42, 70]
assert antidivisors(1) == []
def test_antidivisor_count():
assert antidivisor_count(0) == 0
assert antidivisor_count(-1) == 0
assert antidivisor_count(-4) == 1
assert antidivisor_count(20) == 3
assert antidivisor_count(25) == 5
assert antidivisor_count(38) == 7
assert antidivisor_count(180) == 6
assert antidivisor_count(2*3*5) == 3
def test_smoothness_and_smoothness_p():
assert smoothness(1) == (1, 1)
assert smoothness(2**4*3**2) == (3, 16)
assert smoothness_p(10431, m=1) == \
(1, [(3, (2, 2, 4)), (19, (1, 5, 5)), (61, (1, 31, 31))])
assert smoothness_p(10431) == \
(-1, [(3, (2, 2, 2)), (19, (1, 3, 9)), (61, (1, 5, 5))])
assert smoothness_p(10431, power=1) == \
(-1, [(3, (2, 2, 2)), (61, (1, 5, 5)), (19, (1, 3, 9))])
assert smoothness_p(21477639576571, visual=1) == \
'p**i=4410317**1 has p-1 B=1787, B-pow=1787\n' + \
'p**i=4869863**1 has p-1 B=2434931, B-pow=2434931'
def test_visual_factorint():
assert factorint(1, visual=1) == 1
forty2 = factorint(42, visual=True)
assert type(forty2) == Mul
assert str(forty2) == '2**1*3**1*7**1'
assert factorint(1, visual=True) is S.One
no = dict(evaluate=False)
assert factorint(42**2, visual=True) == Mul(Pow(2, 2, **no),
Pow(3, 2, **no),
Pow(7, 2, **no), **no)
assert -1 in factorint(-42, visual=True).args
def test_factorrat():
assert str(factorrat(S(12)/1, visual=True)) == '2**2*3**1'
assert str(factorrat(S(1)/1, visual=True)) == '1'
assert str(factorrat(S(25)/14, visual=True)) == '5**2/(2*7)'
assert str(factorrat(S(-25)/14/9, visual=True)) == '-5**2/(2*3**2*7)'
assert factorrat(S(12)/1, multiple=True) == [2, 2, 3]
assert factorrat(S(1)/1, multiple=True) == []
assert factorrat(S(25)/14, multiple=True) == [S(1)/7, S(1)/2, 5, 5]
assert factorrat(S(12)/1, multiple=True) == [2, 2, 3]
assert factorrat(S(-25)/14/9, multiple=True) == \
[-1, S(1)/7, S(1)/3, S(1)/3, S(1)/2, 5, 5]
def test_visual_io():
sm = smoothness_p
fi = factorint
# with smoothness_p
n = 124
d = fi(n)
m = fi(d, visual=True)
t = sm(n)
s = sm(t)
for th in [d, s, t, n, m]:
assert sm(th, visual=True) == s
assert sm(th, visual=1) == s
for th in [d, s, t, n, m]:
assert sm(th, visual=False) == t
assert [sm(th, visual=None) for th in [d, s, t, n, m]] == [s, d, s, t, t]
assert [sm(th, visual=2) for th in [d, s, t, n, m]] == [s, d, s, t, t]
# with factorint
for th in [d, m, n]:
assert fi(th, visual=True) == m
assert fi(th, visual=1) == m
for th in [d, m, n]:
assert fi(th, visual=False) == d
assert [fi(th, visual=None) for th in [d, m, n]] == [m, d, d]
assert [fi(th, visual=0) for th in [d, m, n]] == [m, d, d]
# test reevaluation
no = dict(evaluate=False)
assert sm({4: 2}, visual=False) == sm(16)
assert sm(Mul(*[Pow(k, v, **no) for k, v in {4: 2, 2: 6}.items()], **no),
visual=False) == sm(2**10)
assert fi({4: 2}, visual=False) == fi(16)
assert fi(Mul(*[Pow(k, v, **no) for k, v in {4: 2, 2: 6}.items()], **no),
visual=False) == fi(2**10)
def test_core():
assert core(35**13, 10) == 42875
assert core(210**2) == 1
assert core(7776, 3) == 36
assert core(10**27, 22) == 10**5
assert core(537824) == 14
assert core(1, 6) == 1
def test_digits():
assert all([digits(n, 2)[1:] == [int(d) for d in format(n, 'b')]
for n in range(20)])
assert all([digits(n, 8)[1:] == [int(d) for d in format(n, 'o')]
for n in range(20)])
assert all([digits(n, 16)[1:] == [int(d, 16) for d in format(n, 'x')]
for n in range(20)])
assert digits(2345, 34) == [34, 2, 0, 33]
assert digits(384753, 71) == [71, 1, 5, 23, 4]
assert digits(93409) == [10, 9, 3, 4, 0, 9]
assert digits(-92838, 11) == [-11, 6, 3, 8, 2, 9]
def test_primenu():
assert primenu(2) == 1
assert primenu(2 * 3) == 2
assert primenu(2 * 3 * 5) == 3
assert primenu(3 * 25) == primenu(3) + primenu(25)
assert [primenu(p) for p in primerange(1, 10)] == [1, 1, 1, 1]
assert primenu(fac(50)) == 15
assert primenu(2 ** 9941 - 1) == 1
n = Symbol('n', integer=True)
assert primenu(n)
assert primenu(n).subs(n, 2 ** 31 - 1) == 1
assert summation(primenu(n), (n, 2, 30)) == 43
def test_primeomega():
assert primeomega(2) == 1
assert primeomega(2 * 2) == 2
assert primeomega(2 * 2 * 3) == 3
assert primeomega(3 * 25) == primeomega(3) + primeomega(25)
assert [primeomega(p) for p in primerange(1, 10)] == [1, 1, 1, 1]
assert primeomega(fac(50)) == 108
assert primeomega(2 ** 9941 - 1) == 1
n = Symbol('n', integer=True)
assert primeomega(n)
assert primeomega(n).subs(n, 2 ** 31 - 1) == 1
assert summation(primeomega(n), (n, 2, 30)) == 59
|
f3afccfb89c18d41eee459cd15271586080da8018fa43ee90aa654ece72485dd
|
from sympy import (symbols, Symbol, oo, Sum, harmonic, Add, S, binomial,
factorial, log, fibonacci, sin, cos, pi, I, sqrt)
from sympy.series.limitseq import limit_seq
from sympy.series.limitseq import difference_delta as dd
from sympy.utilities.pytest import raises, XFAIL
from sympy.calculus.util import AccumulationBounds
n, m, k = symbols('n m k', integer=True)
def test_difference_delta():
e = n*(n + 1)
e2 = e * k
assert dd(e) == 2*n + 2
assert dd(e2, n, 2) == k*(4*n + 6)
raises(ValueError, lambda: dd(e2))
raises(ValueError, lambda: dd(e2, n, oo))
def test_difference_delta__Sum():
e = Sum(1/k, (k, 1, n))
assert dd(e, n) == 1/(n + 1)
assert dd(e, n, 5) == Add(*[1/(i + n + 1) for i in range(5)])
e = Sum(1/k, (k, 1, 3*n))
assert dd(e, n) == Add(*[1/(i + 3*n + 1) for i in range(3)])
e = n * Sum(1/k, (k, 1, n))
assert dd(e, n) == 1 + Sum(1/k, (k, 1, n))
e = Sum(1/k, (k, 1, n), (m, 1, n))
assert dd(e, n) == harmonic(n)
def test_difference_delta__Add():
e = n + n*(n + 1)
assert dd(e, n) == 2*n + 3
assert dd(e, n, 2) == 4*n + 8
e = n + Sum(1/k, (k, 1, n))
assert dd(e, n) == 1 + 1/(n + 1)
assert dd(e, n, 5) == 5 + Add(*[1/(i + n + 1) for i in range(5)])
def test_difference_delta__Pow():
e = 4**n
assert dd(e, n) == 3*4**n
assert dd(e, n, 2) == 15*4**n
e = 4**(2*n)
assert dd(e, n) == 15*4**(2*n)
assert dd(e, n, 2) == 255*4**(2*n)
e = n**4
assert dd(e, n) == (n + 1)**4 - n**4
e = n**n
assert dd(e, n) == (n + 1)**(n + 1) - n**n
def test_limit_seq():
e = binomial(2*n, n) / Sum(binomial(2*k, k), (k, 1, n))
assert limit_seq(e) == S(3) / 4
assert limit_seq(e, m) == e
e = (5*n**3 + 3*n**2 + 4) / (3*n**3 + 4*n - 5)
assert limit_seq(e, n) == S(5) / 3
e = (harmonic(n) * Sum(harmonic(k), (k, 1, n))) / (n * harmonic(2*n)**2)
assert limit_seq(e, n) == 1
e = Sum(k**2 * Sum(2**m/m, (m, 1, k)), (k, 1, n)) / (2**n*n)
assert limit_seq(e, n) == 4
e = (Sum(binomial(3*k, k) * binomial(5*k, k), (k, 1, n)) /
(binomial(3*n, n) * binomial(5*n, n)))
assert limit_seq(e, n) == S(84375) / 83351
e = Sum(harmonic(k)**2/k, (k, 1, 2*n)) / harmonic(n)**3
assert limit_seq(e, n) == S(1) / 3
raises(ValueError, lambda: limit_seq(e * m))
def test_alternating_sign():
assert limit_seq((-1)**n/n**2, n) == 0
assert limit_seq((-2)**(n+1)/(n + 3**n), n) == 0
assert limit_seq((2*n + (-1)**n)/(n + 1), n) == 2
assert limit_seq(sin(pi*n), n) == 0
assert limit_seq(cos(2*pi*n), n) == 1
assert limit_seq((S(-1)/5)**n, n) == 0
assert limit_seq((-1/5)**n, n) == 0
assert limit_seq((I/3)**n, n) == 0
assert limit_seq(sqrt(n)*(I/2)**n, n) == 0
assert limit_seq(n**7*(I/3)**n, n) == 0
assert limit_seq(n/(n + 1) + (I/2)**n, n) == 1
def test_accum_bounds():
assert limit_seq((-1)**n, n) == AccumulationBounds(-1, 1)
assert limit_seq(cos(pi*n), n) == AccumulationBounds(-1, 1)
assert limit_seq(sin(pi*n/2)**2, n) == AccumulationBounds(0, 1)
assert limit_seq(2*(-3)**n/(n + 3**n), n) == AccumulationBounds(-2, 2)
assert limit_seq(3*n/(n + 1) + 2*(-1)**n, n) == AccumulationBounds(1, 5)
def test_limitseq_sum():
from sympy.abc import x, y, z
assert limit_seq(Sum(1/x, (x, 1, y)) - log(y), y) == S.EulerGamma
assert limit_seq(Sum(1/x, (x, 1, y)) - 1/y, y) == S.Infinity
assert (limit_seq(binomial(2*x, x) / Sum(binomial(2*y, y), (y, 1, x)), x) ==
S(3) / 4)
assert (limit_seq(Sum(y**2 * Sum(2**z/z, (z, 1, y)), (y, 1, x)) /
(2**x*x), x) == 4)
def test_issue_10382():
n = Symbol('n', integer=True)
assert limit_seq(fibonacci(n+1)/fibonacci(n), n) == S.GoldenRatio
@XFAIL
def test_limit_seq_fail():
# improve Summation algorithm or add ad-hoc criteria
e = (harmonic(n)**3 * Sum(1/harmonic(k), (k, 1, n)) /
(n * Sum(harmonic(k)/k, (k, 1, n))))
assert limit_seq(e, n) == 2
# No unique dominant term
e = (Sum(2**k * binomial(2*k, k) / k**2, (k, 1, n)) /
(Sum(2**k/k*2, (k, 1, n)) * Sum(binomial(2*k, k), (k, 1, n))))
assert limit_seq(e, n) == S(3) / 7
# Simplifications of summations needs to be improved.
e = n**3*Sum(2**k/k**2, (k, 1, n))**2 / (2**n * Sum(2**k/k, (k, 1, n)))
assert limit_seq(e, n) == 2
e = (harmonic(n) * Sum(2**k/k, (k, 1, n)) /
(n * Sum(2**k*harmonic(k)/k**2, (k, 1, n))))
assert limit_seq(e, n) == 1
e = (Sum(2**k*factorial(k) / k**2, (k, 1, 2*n)) /
(Sum(4**k/k**2, (k, 1, n)) * Sum(factorial(k), (k, 1, 2*n))))
assert limit_seq(e, n) == S(3) / 16
|
837b039cc8220008d9f81550d24da9f575ae0e90f7305d12e4b1e195b364d453
|
from sympy import (
symbols, sin, simplify, cos, trigsimp, rad, tan, exptrigsimp,sinh,
cosh, diff, cot, Subs, exp, tanh, exp, S, integrate, I,Matrix,
Symbol, coth, pi, log, count_ops, sqrt, E, expand, Piecewise , Rational
)
from sympy.core.compatibility import long
from sympy.utilities.pytest import XFAIL
from sympy.abc import x, y, z, t, a, b, c, d, e, f, g, h, i, k
def test_trigsimp1():
x, y = symbols('x,y')
assert trigsimp(1 - sin(x)**2) == cos(x)**2
assert trigsimp(1 - cos(x)**2) == sin(x)**2
assert trigsimp(sin(x)**2 + cos(x)**2) == 1
assert trigsimp(1 + tan(x)**2) == 1/cos(x)**2
assert trigsimp(1/cos(x)**2 - 1) == tan(x)**2
assert trigsimp(1/cos(x)**2 - tan(x)**2) == 1
assert trigsimp(1 + cot(x)**2) == 1/sin(x)**2
assert trigsimp(1/sin(x)**2 - 1) == 1/tan(x)**2
assert trigsimp(1/sin(x)**2 - cot(x)**2) == 1
assert trigsimp(5*cos(x)**2 + 5*sin(x)**2) == 5
assert trigsimp(5*cos(x/2)**2 + 2*sin(x/2)**2) == 3*cos(x)/2 + S(7)/2
assert trigsimp(sin(x)/cos(x)) == tan(x)
assert trigsimp(2*tan(x)*cos(x)) == 2*sin(x)
assert trigsimp(cot(x)**3*sin(x)**3) == cos(x)**3
assert trigsimp(y*tan(x)**2/sin(x)**2) == y/cos(x)**2
assert trigsimp(cot(x)/cos(x)) == 1/sin(x)
assert trigsimp(sin(x + y) + sin(x - y)) == 2*sin(x)*cos(y)
assert trigsimp(sin(x + y) - sin(x - y)) == 2*sin(y)*cos(x)
assert trigsimp(cos(x + y) + cos(x - y)) == 2*cos(x)*cos(y)
assert trigsimp(cos(x + y) - cos(x - y)) == -2*sin(x)*sin(y)
assert trigsimp(tan(x + y) - tan(x)/(1 - tan(x)*tan(y))) == \
sin(y)/(-sin(y)*tan(x) + cos(y)) # -tan(y)/(tan(x)*tan(y) - 1)
assert trigsimp(sinh(x + y) + sinh(x - y)) == 2*sinh(x)*cosh(y)
assert trigsimp(sinh(x + y) - sinh(x - y)) == 2*sinh(y)*cosh(x)
assert trigsimp(cosh(x + y) + cosh(x - y)) == 2*cosh(x)*cosh(y)
assert trigsimp(cosh(x + y) - cosh(x - y)) == 2*sinh(x)*sinh(y)
assert trigsimp(tanh(x + y) - tanh(x)/(1 + tanh(x)*tanh(y))) == \
sinh(y)/(sinh(y)*tanh(x) + cosh(y))
assert trigsimp(cos(0.12345)**2 + sin(0.12345)**2) == 1
e = 2*sin(x)**2 + 2*cos(x)**2
assert trigsimp(log(e)) == log(2)
def test_trigsimp1a():
assert trigsimp(sin(2)**2*cos(3)*exp(2)/cos(2)**2) == tan(2)**2*cos(3)*exp(2)
assert trigsimp(tan(2)**2*cos(3)*exp(2)*cos(2)**2) == sin(2)**2*cos(3)*exp(2)
assert trigsimp(cot(2)*cos(3)*exp(2)*sin(2)) == cos(3)*exp(2)*cos(2)
assert trigsimp(tan(2)*cos(3)*exp(2)/sin(2)) == cos(3)*exp(2)/cos(2)
assert trigsimp(cot(2)*cos(3)*exp(2)/cos(2)) == cos(3)*exp(2)/sin(2)
assert trigsimp(cot(2)*cos(3)*exp(2)*tan(2)) == cos(3)*exp(2)
assert trigsimp(sinh(2)*cos(3)*exp(2)/cosh(2)) == tanh(2)*cos(3)*exp(2)
assert trigsimp(tanh(2)*cos(3)*exp(2)*cosh(2)) == sinh(2)*cos(3)*exp(2)
assert trigsimp(coth(2)*cos(3)*exp(2)*sinh(2)) == cosh(2)*cos(3)*exp(2)
assert trigsimp(tanh(2)*cos(3)*exp(2)/sinh(2)) == cos(3)*exp(2)/cosh(2)
assert trigsimp(coth(2)*cos(3)*exp(2)/cosh(2)) == cos(3)*exp(2)/sinh(2)
assert trigsimp(coth(2)*cos(3)*exp(2)*tanh(2)) == cos(3)*exp(2)
def test_trigsimp2():
x, y = symbols('x,y')
assert trigsimp(cos(x)**2*sin(y)**2 + cos(x)**2*cos(y)**2 + sin(x)**2,
recursive=True) == 1
assert trigsimp(sin(x)**2*sin(y)**2 + sin(x)**2*cos(y)**2 + cos(x)**2,
recursive=True) == 1
assert trigsimp(
Subs(x, x, sin(y)**2 + cos(y)**2)) == Subs(x, x, 1)
def test_issue_4373():
x = Symbol("x")
assert abs(trigsimp(2.0*sin(x)**2 + 2.0*cos(x)**2) - 2.0) < 1e-10
def test_trigsimp3():
x, y = symbols('x,y')
assert trigsimp(sin(x)/cos(x)) == tan(x)
assert trigsimp(sin(x)**2/cos(x)**2) == tan(x)**2
assert trigsimp(sin(x)**3/cos(x)**3) == tan(x)**3
assert trigsimp(sin(x)**10/cos(x)**10) == tan(x)**10
assert trigsimp(cos(x)/sin(x)) == 1/tan(x)
assert trigsimp(cos(x)**2/sin(x)**2) == 1/tan(x)**2
assert trigsimp(cos(x)**10/sin(x)**10) == 1/tan(x)**10
assert trigsimp(tan(x)) == trigsimp(sin(x)/cos(x))
def test_issue_4661():
a, x, y = symbols('a x y')
eq = -4*sin(x)**4 + 4*cos(x)**4 - 8*cos(x)**2
assert trigsimp(eq) == -4
n = sin(x)**6 + 4*sin(x)**4*cos(x)**2 + 5*sin(x)**2*cos(x)**4 + 2*cos(x)**6
d = -sin(x)**2 - 2*cos(x)**2
assert simplify(n/d) == -1
assert trigsimp(-2*cos(x)**2 + cos(x)**4 - sin(x)**4) == -1
eq = (- sin(x)**3/4)*cos(x) + (cos(x)**3/4)*sin(x) - sin(2*x)*cos(2*x)/8
assert trigsimp(eq) == 0
def test_issue_4494():
a, b = symbols('a b')
eq = sin(a)**2*sin(b)**2 + cos(a)**2*cos(b)**2*tan(a)**2 + cos(a)**2
assert trigsimp(eq) == 1
def test_issue_5948():
a, x, y = symbols('a x y')
assert trigsimp(diff(integrate(cos(x)/sin(x)**7, x), x)) == \
cos(x)/sin(x)**7
def test_issue_4775():
a, x, y = symbols('a x y')
assert trigsimp(sin(x)*cos(y)+cos(x)*sin(y)) == sin(x + y)
assert trigsimp(sin(x)*cos(y)+cos(x)*sin(y)+3) == sin(x + y) + 3
def test_issue_4280():
a, x, y = symbols('a x y')
assert trigsimp(cos(x)**2 + cos(y)**2*sin(x)**2 + sin(y)**2*sin(x)**2) == 1
assert trigsimp(a**2*sin(x)**2 + a**2*cos(y)**2*cos(x)**2 + a**2*cos(x)**2*sin(y)**2) == a**2
assert trigsimp(a**2*cos(y)**2*sin(x)**2 + a**2*sin(y)**2*sin(x)**2) == a**2*sin(x)**2
def test_issue_3210():
eqs = (sin(2)*cos(3) + sin(3)*cos(2),
-sin(2)*sin(3) + cos(2)*cos(3),
sin(2)*cos(3) - sin(3)*cos(2),
sin(2)*sin(3) + cos(2)*cos(3),
sin(2)*sin(3) + cos(2)*cos(3) + cos(2),
sinh(2)*cosh(3) + sinh(3)*cosh(2),
sinh(2)*sinh(3) + cosh(2)*cosh(3),
)
assert [trigsimp(e) for e in eqs] == [
sin(5),
cos(5),
-sin(1),
cos(1),
cos(1) + cos(2),
sinh(5),
cosh(5),
]
def test_trigsimp_issues():
a, x, y = symbols('a x y')
# issue 4625 - factor_terms works, too
assert trigsimp(sin(x)**3 + cos(x)**2*sin(x)) == sin(x)
# issue 5948
assert trigsimp(diff(integrate(cos(x)/sin(x)**3, x), x)) == \
cos(x)/sin(x)**3
assert trigsimp(diff(integrate(sin(x)/cos(x)**3, x), x)) == \
sin(x)/cos(x)**3
# check integer exponents
e = sin(x)**y/cos(x)**y
assert trigsimp(e) == e
assert trigsimp(e.subs(y, 2)) == tan(x)**2
assert trigsimp(e.subs(x, 1)) == tan(1)**y
# check for multiple patterns
assert (cos(x)**2/sin(x)**2*cos(y)**2/sin(y)**2).trigsimp() == \
1/tan(x)**2/tan(y)**2
assert trigsimp(cos(x)/sin(x)*cos(x+y)/sin(x+y)) == \
1/(tan(x)*tan(x + y))
eq = cos(2)*(cos(3) + 1)**2/(cos(3) - 1)**2
assert trigsimp(eq) == eq.factor() # factor makes denom (-1 + cos(3))**2
assert trigsimp(cos(2)*(cos(3) + 1)**2*(cos(3) - 1)**2) == \
cos(2)*sin(3)**4
# issue 6789; this generates an expression that formerly caused
# trigsimp to hang
assert cot(x).equals(tan(x)) is False
# nan or the unchanged expression is ok, but not sin(1)
z = cos(x)**2 + sin(x)**2 - 1
z1 = tan(x)**2 - 1/cot(x)**2
n = (1 + z1/z)
assert trigsimp(sin(n)) != sin(1)
eq = x*(n - 1) - x*n
assert trigsimp(eq) is S.NaN
assert trigsimp(eq, recursive=True) is S.NaN
assert trigsimp(1).is_Integer
assert trigsimp(-sin(x)**4 - 2*sin(x)**2*cos(x)**2 - cos(x)**4) == -1
def test_trigsimp_issue_2515():
x = Symbol('x')
assert trigsimp(x*cos(x)*tan(x)) == x*sin(x)
assert trigsimp(-sin(x) + cos(x)*tan(x)) == 0
def test_trigsimp_issue_3826():
assert trigsimp(tan(2*x).expand(trig=True)) == tan(2*x)
def test_trigsimp_issue_4032():
n = Symbol('n', integer=True, positive=True)
assert trigsimp(2**(n/2)*cos(pi*n/4)/2 + 2**(n - 1)/2) == \
2**(n/2)*cos(pi*n/4)/2 + 2**n/4
def test_trigsimp_issue_7761():
assert trigsimp(cosh(pi/4)) == cosh(pi/4)
def test_trigsimp_noncommutative():
x, y = symbols('x,y')
A, B = symbols('A,B', commutative=False)
assert trigsimp(A - A*sin(x)**2) == A*cos(x)**2
assert trigsimp(A - A*cos(x)**2) == A*sin(x)**2
assert trigsimp(A*sin(x)**2 + A*cos(x)**2) == A
assert trigsimp(A + A*tan(x)**2) == A/cos(x)**2
assert trigsimp(A/cos(x)**2 - A) == A*tan(x)**2
assert trigsimp(A/cos(x)**2 - A*tan(x)**2) == A
assert trigsimp(A + A*cot(x)**2) == A/sin(x)**2
assert trigsimp(A/sin(x)**2 - A) == A/tan(x)**2
assert trigsimp(A/sin(x)**2 - A*cot(x)**2) == A
assert trigsimp(y*A*cos(x)**2 + y*A*sin(x)**2) == y*A
assert trigsimp(A*sin(x)/cos(x)) == A*tan(x)
assert trigsimp(A*tan(x)*cos(x)) == A*sin(x)
assert trigsimp(A*cot(x)**3*sin(x)**3) == A*cos(x)**3
assert trigsimp(y*A*tan(x)**2/sin(x)**2) == y*A/cos(x)**2
assert trigsimp(A*cot(x)/cos(x)) == A/sin(x)
assert trigsimp(A*sin(x + y) + A*sin(x - y)) == 2*A*sin(x)*cos(y)
assert trigsimp(A*sin(x + y) - A*sin(x - y)) == 2*A*sin(y)*cos(x)
assert trigsimp(A*cos(x + y) + A*cos(x - y)) == 2*A*cos(x)*cos(y)
assert trigsimp(A*cos(x + y) - A*cos(x - y)) == -2*A*sin(x)*sin(y)
assert trigsimp(A*sinh(x + y) + A*sinh(x - y)) == 2*A*sinh(x)*cosh(y)
assert trigsimp(A*sinh(x + y) - A*sinh(x - y)) == 2*A*sinh(y)*cosh(x)
assert trigsimp(A*cosh(x + y) + A*cosh(x - y)) == 2*A*cosh(x)*cosh(y)
assert trigsimp(A*cosh(x + y) - A*cosh(x - y)) == 2*A*sinh(x)*sinh(y)
assert trigsimp(A*cos(0.12345)**2 + A*sin(0.12345)**2) == 1.0*A
def test_hyperbolic_simp():
x, y = symbols('x,y')
assert trigsimp(sinh(x)**2 + 1) == cosh(x)**2
assert trigsimp(cosh(x)**2 - 1) == sinh(x)**2
assert trigsimp(cosh(x)**2 - sinh(x)**2) == 1
assert trigsimp(1 - tanh(x)**2) == 1/cosh(x)**2
assert trigsimp(1 - 1/cosh(x)**2) == tanh(x)**2
assert trigsimp(tanh(x)**2 + 1/cosh(x)**2) == 1
assert trigsimp(coth(x)**2 - 1) == 1/sinh(x)**2
assert trigsimp(1/sinh(x)**2 + 1) == 1/tanh(x)**2
assert trigsimp(coth(x)**2 - 1/sinh(x)**2) == 1
assert trigsimp(5*cosh(x)**2 - 5*sinh(x)**2) == 5
assert trigsimp(5*cosh(x/2)**2 - 2*sinh(x/2)**2) == 3*cosh(x)/2 + S(7)/2
assert trigsimp(sinh(x)/cosh(x)) == tanh(x)
assert trigsimp(tanh(x)) == trigsimp(sinh(x)/cosh(x))
assert trigsimp(cosh(x)/sinh(x)) == 1/tanh(x)
assert trigsimp(2*tanh(x)*cosh(x)) == 2*sinh(x)
assert trigsimp(coth(x)**3*sinh(x)**3) == cosh(x)**3
assert trigsimp(y*tanh(x)**2/sinh(x)**2) == y/cosh(x)**2
assert trigsimp(coth(x)/cosh(x)) == 1/sinh(x)
for a in (pi/6*I, pi/4*I, pi/3*I):
assert trigsimp(sinh(a)*cosh(x) + cosh(a)*sinh(x)) == sinh(x + a)
assert trigsimp(-sinh(a)*cosh(x) + cosh(a)*sinh(x)) == sinh(x - a)
e = 2*cosh(x)**2 - 2*sinh(x)**2
assert trigsimp(log(e)) == log(2)
assert trigsimp(cosh(x)**2*cosh(y)**2 - cosh(x)**2*sinh(y)**2 - sinh(x)**2,
recursive=True) == 1
assert trigsimp(sinh(x)**2*sinh(y)**2 - sinh(x)**2*cosh(y)**2 + cosh(x)**2,
recursive=True) == 1
assert abs(trigsimp(2.0*cosh(x)**2 - 2.0*sinh(x)**2) - 2.0) < 1e-10
assert trigsimp(sinh(x)**2/cosh(x)**2) == tanh(x)**2
assert trigsimp(sinh(x)**3/cosh(x)**3) == tanh(x)**3
assert trigsimp(sinh(x)**10/cosh(x)**10) == tanh(x)**10
assert trigsimp(cosh(x)**3/sinh(x)**3) == 1/tanh(x)**3
assert trigsimp(cosh(x)/sinh(x)) == 1/tanh(x)
assert trigsimp(cosh(x)**2/sinh(x)**2) == 1/tanh(x)**2
assert trigsimp(cosh(x)**10/sinh(x)**10) == 1/tanh(x)**10
assert trigsimp(x*cosh(x)*tanh(x)) == x*sinh(x)
assert trigsimp(-sinh(x) + cosh(x)*tanh(x)) == 0
assert tan(x) != 1/cot(x) # cot doesn't auto-simplify
assert trigsimp(tan(x) - 1/cot(x)) == 0
assert trigsimp(3*tanh(x)**7 - 2/coth(x)**7) == tanh(x)**7
def test_trigsimp_groebner():
from sympy.simplify.trigsimp import trigsimp_groebner
c = cos(x)
s = sin(x)
ex = (4*s*c + 12*s + 5*c**3 + 21*c**2 + 23*c + 15)/(
-s*c**2 + 2*s*c + 15*s + 7*c**3 + 31*c**2 + 37*c + 21)
resnum = (5*s - 5*c + 1)
resdenom = (8*s - 6*c)
results = [resnum/resdenom, (-resnum)/(-resdenom)]
assert trigsimp_groebner(ex) in results
assert trigsimp_groebner(s/c, hints=[tan]) == tan(x)
assert trigsimp_groebner(c*s) == c*s
assert trigsimp((-s + 1)/c + c/(-s + 1),
method='groebner') == 2/c
assert trigsimp((-s + 1)/c + c/(-s + 1),
method='groebner', polynomial=True) == 2/c
# Test quick=False works
assert trigsimp_groebner(ex, hints=[2]) in results
assert trigsimp_groebner(ex, hints=[long(2)]) in results
# test "I"
assert trigsimp_groebner(sin(I*x)/cos(I*x), hints=[tanh]) == I*tanh(x)
# test hyperbolic / sums
assert trigsimp_groebner((tanh(x)+tanh(y))/(1+tanh(x)*tanh(y)),
hints=[(tanh, x, y)]) == tanh(x + y)
def test_issue_2827_trigsimp_methods():
measure1 = lambda expr: len(str(expr))
measure2 = lambda expr: -count_ops(expr)
# Return the most complicated result
expr = (x + 1)/(x + sin(x)**2 + cos(x)**2)
ans = Matrix([1])
M = Matrix([expr])
assert trigsimp(M, method='fu', measure=measure1) == ans
assert trigsimp(M, method='fu', measure=measure2) != ans
# all methods should work with Basic expressions even if they
# aren't Expr
M = Matrix.eye(1)
assert all(trigsimp(M, method=m) == M for m in
'fu matching groebner old'.split())
# watch for E in exptrigsimp, not only exp()
eq = 1/sqrt(E) + E
assert exptrigsimp(eq) == eq
def test_issue_15129_trigsimp_methods():
t1 = Matrix([sin(Rational(1, 50)), cos(Rational(1, 50)), 0])
t2 = Matrix([sin(Rational(1, 25)), cos(Rational(1, 25)), 0])
t3 = Matrix([cos(Rational(1, 25)), sin(Rational(1, 25)), 0])
r1 = t1.dot(t2)
r2 = t1.dot(t3)
assert trigsimp(r1) == cos(S(1)/50)
assert trigsimp(r2) == sin(S(3)/50)
def test_exptrigsimp():
def valid(a, b):
from sympy.utilities.randtest import verify_numerically as tn
if not (tn(a, b) and a == b):
return False
return True
assert exptrigsimp(exp(x) + exp(-x)) == 2*cosh(x)
assert exptrigsimp(exp(x) - exp(-x)) == 2*sinh(x)
assert exptrigsimp((2*exp(x)-2*exp(-x))/(exp(x)+exp(-x))) == 2*tanh(x)
assert exptrigsimp((2*exp(2*x)-2)/(exp(2*x)+1)) == 2*tanh(x)
e = [cos(x) + I*sin(x), cos(x) - I*sin(x),
cosh(x) - sinh(x), cosh(x) + sinh(x)]
ok = [exp(I*x), exp(-I*x), exp(-x), exp(x)]
assert all(valid(i, j) for i, j in zip(
[exptrigsimp(ei) for ei in e], ok))
ue = [cos(x) + sin(x), cos(x) - sin(x),
cosh(x) + I*sinh(x), cosh(x) - I*sinh(x)]
assert [exptrigsimp(ei) == ei for ei in ue]
res = []
ok = [y*tanh(1), 1/(y*tanh(1)), I*y*tan(1), -I/(y*tan(1)),
y*tanh(x), 1/(y*tanh(x)), I*y*tan(x), -I/(y*tan(x)),
y*tanh(1 + I), 1/(y*tanh(1 + I))]
for a in (1, I, x, I*x, 1 + I):
w = exp(a)
eq = y*(w - 1/w)/(w + 1/w)
res.append(simplify(eq))
res.append(simplify(1/eq))
assert all(valid(i, j) for i, j in zip(res, ok))
for a in range(1, 3):
w = exp(a)
e = w + 1/w
s = simplify(e)
assert s == exptrigsimp(e)
assert valid(s, 2*cosh(a))
e = w - 1/w
s = simplify(e)
assert s == exptrigsimp(e)
assert valid(s, 2*sinh(a))
def test_exptrigsimp_noncommutative():
a,b = symbols('a b', commutative=False)
x = Symbol('x', commutative=True)
assert exp(a + x) == exptrigsimp(exp(a)*exp(x))
p = exp(a)*exp(b) - exp(b)*exp(a)
assert p == exptrigsimp(p) != 0
def test_powsimp_on_numbers():
assert 2**(S(1)/3 - 2) == 2**(S(1)/3)/4
@XFAIL
def test_issue_6811_fail():
# from doc/src/modules/physics/mechanics/examples.rst, the current `eq`
# at Line 576 (in different variables) was formerly the equivalent and
# shorter expression given below...it would be nice to get the short one
# back again
xp, y, x, z = symbols('xp, y, x, z')
eq = 4*(-19*sin(x)*y + 5*sin(3*x)*y + 15*cos(2*x)*z - 21*z)*xp/(9*cos(x) - 5*cos(3*x))
assert trigsimp(eq) == -2*(2*cos(x)*tan(x)*y + 3*z)*xp/cos(x)
def test_Piecewise():
e1 = x*(x + y) - y*(x + y)
e2 = sin(x)**2 + cos(x)**2
e3 = expand((x + y)*y/x)
s1 = simplify(e1)
s2 = simplify(e2)
s3 = simplify(e3)
# trigsimp tries not to touch non-trig containing args
assert trigsimp(Piecewise((e1, e3 < e2), (e3, True))) == \
Piecewise((e1, e3 < s2), (e3, True))
|
2d3321e509ac3e4101edf2602219a82442e1e336d7c5c9aacc217a41f55f07b2
|
from sympy import (
symbols, powsimp, symbols, MatrixSymbol, sqrt, pi, Mul, gamma, Function,
S, I, exp, simplify, sin, E, log, hyper, Symbol, Dummy, powdenest, root,
Rational, oo)
from sympy.abc import x, y, z, t, a, b, c, d, e, f, g, h, i, k
def test_powsimp():
x, y, z, n = symbols('x,y,z,n')
f = Function('f')
assert powsimp( 4**x * 2**(-x) * 2**(-x) ) == 1
assert powsimp( (-4)**x * (-2)**(-x) * 2**(-x) ) == 1
assert powsimp(
f(4**x * 2**(-x) * 2**(-x)) ) == f(4**x * 2**(-x) * 2**(-x))
assert powsimp( f(4**x * 2**(-x) * 2**(-x)), deep=True ) == f(1)
assert exp(x)*exp(y) == exp(x)*exp(y)
assert powsimp(exp(x)*exp(y)) == exp(x + y)
assert powsimp(exp(x)*exp(y)*2**x*2**y) == (2*E)**(x + y)
assert powsimp(exp(x)*exp(y)*2**x*2**y, combine='exp') == \
exp(x + y)*2**(x + y)
assert powsimp(exp(x)*exp(y)*exp(2)*sin(x) + sin(y) + 2**x*2**y) == \
exp(2 + x + y)*sin(x) + sin(y) + 2**(x + y)
assert powsimp(sin(exp(x)*exp(y))) == sin(exp(x)*exp(y))
assert powsimp(sin(exp(x)*exp(y)), deep=True) == sin(exp(x + y))
assert powsimp(x**2*x**y) == x**(2 + y)
# This should remain factored, because 'exp' with deep=True is supposed
# to act like old automatic exponent combining.
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp', deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), deep=True) == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E)) == (1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='exp') == \
(1 + exp(1 + E))*exp(-E)
assert powsimp((1 + E*exp(E))*exp(-E), combine='base') == \
(1 + E*exp(E))*exp(-E)
x, y = symbols('x,y', nonnegative=True)
n = Symbol('n', real=True)
assert powsimp(y**n * (y/x)**(-n)) == x**n
assert powsimp(x**(x**(x*y)*y**(x*y))*y**(x**(x*y)*y**(x*y)), deep=True) \
== (x*y)**(x*y)**(x*y)
assert powsimp(2**(2**(2*x)*x), deep=False) == 2**(2**(2*x)*x)
assert powsimp(2**(2**(2*x)*x), deep=True) == 2**(x*4**x)
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp(
exp(-x + exp(-x)*exp(-x*log(x))), deep=False, combine='exp') == \
exp(-x + exp(-x)*exp(-x*log(x)))
assert powsimp((x + y)/(3*z), deep=False, combine='exp') == (x + y)/(3*z)
assert powsimp((x/3 + y/3)/z, deep=True, combine='exp') == (x/3 + y/3)/z
assert powsimp(exp(x)/(1 + exp(x)*exp(y)), deep=True) == \
exp(x)/(1 + exp(x + y))
assert powsimp(x*y**(z**x*z**y), deep=True) == x*y**(z**(x + y))
assert powsimp((z**x*z**y)**x, deep=True) == (z**(x + y))**x
assert powsimp(x*(z**x*z**y)**x, deep=True) == x*(z**(x + y))**x
p = symbols('p', positive=True)
assert powsimp((1/x)**log(2)/x) == (1/x)**(1 + log(2))
assert powsimp((1/p)**log(2)/p) == p**(-1 - log(2))
# coefficient of exponent can only be simplified for positive bases
assert powsimp(2**(2*x)) == 4**x
assert powsimp((-1)**(2*x)) == (-1)**(2*x)
i = symbols('i', integer=True)
assert powsimp((-1)**(2*i)) == 1
assert powsimp((-1)**(-x)) != (-1)**x # could be 1/((-1)**x), but is not
# force=True overrides assumptions
assert powsimp((-1)**(2*x), force=True) == 1
# rational exponents allow combining of negative terms
w, n, m = symbols('w n m', negative=True)
e = i/a # not a rational exponent if `a` is unknown
ex = w**e*n**e*m**e
assert powsimp(ex) == m**(i/a)*n**(i/a)*w**(i/a)
e = i/3
ex = w**e*n**e*m**e
assert powsimp(ex) == (-1)**i*(-m*n*w)**(i/3)
e = (3 + i)/i
ex = w**e*n**e*m**e
assert powsimp(ex) == (-1)**(3*e)*(-m*n*w)**e
eq = x**(2*a/3)
# eq != (x**a)**(2/3) (try x = -1 and a = 3 to see)
assert powsimp(eq).exp == eq.exp == 2*a/3
# powdenest goes the other direction
assert powsimp(2**(2*x)) == 4**x
assert powsimp(exp(p/2)) == exp(p/2)
# issue 6368
eq = Mul(*[sqrt(Dummy(imaginary=True)) for i in range(3)])
assert powsimp(eq) == eq and eq.is_Mul
assert all(powsimp(e) == e for e in (sqrt(x**a), sqrt(x**2)))
# issue 8836
assert str( powsimp(exp(I*pi/3)*root(-1,3)) ) == '(-1)**(2/3)'
# issue 9183
assert powsimp(-0.1**x) == -0.1**x
# issue 10095
assert powsimp((1/(2*E))**oo) == (exp(-1)/2)**oo
# PR 13131
eq = sin(2*x)**2*sin(2.0*x)**2
assert powsimp(eq) == eq
# issue 14615
assert powsimp(x**2*y**3*(x*y**2)**(S(3)/2)
) == x*y*(x*y**2)**(S(5)/2)
def test_powsimp_negated_base():
assert powsimp((-x + y)/sqrt(x - y)) == -sqrt(x - y)
assert powsimp((-x + y)*(-z + y)/sqrt(x - y)/sqrt(z - y)) == sqrt(x - y)*sqrt(z - y)
p = symbols('p', positive=True)
assert powsimp((-p)**a/p**a) == (-1)**a
n = symbols('n', negative=True)
assert powsimp((-n)**a/n**a) == (-1)**a
# if x is 0 then the lhs is 0**a*oo**a which is not (-1)**a
assert powsimp((-x)**a/x**a) != (-1)**a
def test_powsimp_nc():
x, y, z = symbols('x,y,z')
A, B, C = symbols('A B C', commutative=False)
assert powsimp(A**x*A**y, combine='all') == A**(x + y)
assert powsimp(A**x*A**y, combine='base') == A**x*A**y
assert powsimp(A**x*A**y, combine='exp') == A**(x + y)
assert powsimp(A**x*B**x, combine='all') == A**x*B**x
assert powsimp(A**x*B**x, combine='base') == A**x*B**x
assert powsimp(A**x*B**x, combine='exp') == A**x*B**x
assert powsimp(B**x*A**x, combine='all') == B**x*A**x
assert powsimp(B**x*A**x, combine='base') == B**x*A**x
assert powsimp(B**x*A**x, combine='exp') == B**x*A**x
assert powsimp(A**x*A**y*A**z, combine='all') == A**(x + y + z)
assert powsimp(A**x*A**y*A**z, combine='base') == A**x*A**y*A**z
assert powsimp(A**x*A**y*A**z, combine='exp') == A**(x + y + z)
assert powsimp(A**x*B**x*C**x, combine='all') == A**x*B**x*C**x
assert powsimp(A**x*B**x*C**x, combine='base') == A**x*B**x*C**x
assert powsimp(A**x*B**x*C**x, combine='exp') == A**x*B**x*C**x
assert powsimp(B**x*A**x*C**x, combine='all') == B**x*A**x*C**x
assert powsimp(B**x*A**x*C**x, combine='base') == B**x*A**x*C**x
assert powsimp(B**x*A**x*C**x, combine='exp') == B**x*A**x*C**x
def test_issue_6440():
assert powsimp(16*2**a*8**b) == 2**(a + 3*b + 4)
def test_powdenest():
from sympy import powdenest
from sympy.abc import x, y, z, a, b
p, q = symbols('p q', positive=True)
i, j = symbols('i,j', integer=True)
assert powdenest(x) == x
assert powdenest(x + 2*(x**(2*a/3))**(3*x)) == (x + 2*(x**(2*a/3))**(3*x))
assert powdenest((exp(2*a/3))**(3*x)) # -X-> (exp(a/3))**(6*x)
assert powdenest((x**(2*a/3))**(3*x)) == ((x**(2*a/3))**(3*x))
assert powdenest(exp(3*x*log(2))) == 2**(3*x)
assert powdenest(sqrt(p**2)) == p
i, j = symbols('i,j', integer=True)
eq = p**(2*i)*q**(4*i)
assert powdenest(eq) == (p*q**2)**(2*i)
# -X-> (x**x)**i*(x**x)**j == x**(x*(i + j))
assert powdenest((x**x)**(i + j))
assert powdenest(exp(3*y*log(x))) == x**(3*y)
assert powdenest(exp(y*(log(a) + log(b)))) == (a*b)**y
assert powdenest(exp(3*(log(a) + log(b)))) == a**3*b**3
assert powdenest(((x**(2*i))**(3*y))**x) == ((x**(2*i))**(3*y))**x
assert powdenest(((x**(2*i))**(3*y))**x, force=True) == x**(6*i*x*y)
assert powdenest(((x**(2*a/3))**(3*y/i))**x) == \
(((x**(2*a/3))**(3*y/i))**x)
assert powdenest((x**(2*i)*y**(4*i))**z, force=True) == (x*y**2)**(2*i*z)
assert powdenest((p**(2*i)*q**(4*i))**j) == (p*q**2)**(2*i*j)
e = ((p**(2*a))**(3*y))**x
assert powdenest(e) == e
e = ((x**2*y**4)**a)**(x*y)
assert powdenest(e) == e
e = (((x**2*y**4)**a)**(x*y))**3
assert powdenest(e) == ((x**2*y**4)**a)**(3*x*y)
assert powdenest((((x**2*y**4)**a)**(x*y)), force=True) == \
(x*y**2)**(2*a*x*y)
assert powdenest((((x**2*y**4)**a)**(x*y))**3, force=True) == \
(x*y**2)**(6*a*x*y)
assert powdenest((x**2*y**6)**i) != (x*y**3)**(2*i)
x, y = symbols('x,y', positive=True)
assert powdenest((x**2*y**6)**i) == (x*y**3)**(2*i)
assert powdenest((x**(2*i/3)*y**(i/2))**(2*i)) == (x**(S(4)/3)*y)**(i**2)
assert powdenest(sqrt(x**(2*i)*y**(6*i))) == (x*y**3)**i
assert powdenest(4**x) == 2**(2*x)
assert powdenest((4**x)**y) == 2**(2*x*y)
assert powdenest(4**x*y) == 2**(2*x)*y
def test_powdenest_polar():
x, y, z = symbols('x y z', polar=True)
a, b, c = symbols('a b c')
assert powdenest((x*y*z)**a) == x**a*y**a*z**a
assert powdenest((x**a*y**b)**c) == x**(a*c)*y**(b*c)
assert powdenest(((x**a)**b*y**c)**c) == x**(a*b*c)*y**(c**2)
def test_issue_5805():
arg = ((gamma(x)*hyper((), (), x))*pi)**2
assert powdenest(arg) == (pi*gamma(x)*hyper((), (), x))**2
assert arg.is_positive is None
def test_issue_9324_powsimp_on_matrix_symbol():
M = MatrixSymbol('M', 10, 10)
expr = powsimp(M, deep=True)
assert expr == M
assert expr.args[0] == 'M'
def test_issue_6367():
z = -5*sqrt(2)/(2*sqrt(2*sqrt(29) + 29)) + sqrt(-sqrt(29)/29 + S(1)/2)
assert Mul(*[powsimp(a) for a in Mul.make_args(z.normal())]) == 0
assert powsimp(z.normal()) == 0
assert simplify(z) == 0
assert powsimp(sqrt(2 + sqrt(3))*sqrt(2 - sqrt(3)) + 1) == 2
assert powsimp(z) != 0
def test_powsimp_polar():
from sympy import polar_lift, exp_polar
x, y, z = symbols('x y z')
p, q, r = symbols('p q r', polar=True)
assert (polar_lift(-1))**(2*x) == exp_polar(2*pi*I*x)
assert powsimp(p**x * q**x) == (p*q)**x
assert p**x * (1/p)**x == 1
assert (1/p)**x == p**(-x)
assert exp_polar(x)*exp_polar(y) == exp_polar(x)*exp_polar(y)
assert powsimp(exp_polar(x)*exp_polar(y)) == exp_polar(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y) == \
(p*exp_polar(1))**(x + y)
assert powsimp(exp_polar(x)*exp_polar(y)*p**x*p**y, combine='exp') == \
exp_polar(x + y)*p**(x + y)
assert powsimp(
exp_polar(x)*exp_polar(y)*exp_polar(2)*sin(x) + sin(y) + p**x*p**y) \
== p**(x + y) + sin(x)*exp_polar(2 + x + y) + sin(y)
assert powsimp(sin(exp_polar(x)*exp_polar(y))) == \
sin(exp_polar(x)*exp_polar(y))
assert powsimp(sin(exp_polar(x)*exp_polar(y)), deep=True) == \
sin(exp_polar(x + y))
def test_issue_5728():
b = x*sqrt(y)
a = sqrt(b)
c = sqrt(sqrt(x)*y)
assert powsimp(a*b) == sqrt(b)**3
assert powsimp(a*b**2*sqrt(y)) == sqrt(y)*a**5
assert powsimp(a*x**2*c**3*y) == c**3*a**5
assert powsimp(a*x*c**3*y**2) == c**7*a
assert powsimp(x*c**3*y**2) == c**7
assert powsimp(x*c**3*y) == x*y*c**3
assert powsimp(sqrt(x)*c**3*y) == c**5
assert powsimp(sqrt(x)*a**3*sqrt(y)) == sqrt(x)*sqrt(y)*a**3
assert powsimp(Mul(sqrt(x)*c**3*sqrt(y), y, evaluate=False)) == \
sqrt(x)*sqrt(y)**3*c**3
assert powsimp(a**2*a*x**2*y) == a**7
# symbolic powers work, too
b = x**y*y
a = b*sqrt(b)
assert a.is_Mul is True
assert powsimp(a) == sqrt(b)**3
# as does exp
a = x*exp(2*y/3)
assert powsimp(a*sqrt(a)) == sqrt(a)**3
assert powsimp(a**2*sqrt(a)) == sqrt(a)**5
assert powsimp(a**2*sqrt(sqrt(a))) == sqrt(sqrt(a))**9
def test_issue_from_PR1599():
n1, n2, n3, n4 = symbols('n1 n2 n3 n4', negative=True)
assert (powsimp(sqrt(n1)*sqrt(n2)*sqrt(n3)) ==
-I*sqrt(-n1)*sqrt(-n2)*sqrt(-n3))
assert (powsimp(root(n1, 3)*root(n2, 3)*root(n3, 3)*root(n4, 3)) ==
-(-1)**(S(1)/3)*
(-n1)**(S(1)/3)*(-n2)**(S(1)/3)*(-n3)**(S(1)/3)*(-n4)**(S(1)/3))
def test_issue_10195():
a = Symbol('a', integer=True)
l = Symbol('l', even=True, nonzero=True)
n = Symbol('n', odd=True)
e_x = (-1)**(n/2 - Rational(1, 2)) - (-1)**(3*n/2 - Rational(1, 2))
assert powsimp((-1)**(l/2)) == I**l
assert powsimp((-1)**(n/2)) == I**n
assert powsimp((-1)**(3*n/2)) == -I**n
assert powsimp(e_x) == (-1)**(n/2 - Rational(1, 2)) + (-1)**(3*n/2 +
Rational(1,2))
assert powsimp((-1)**(3*a/2)) == (-I)**a
def test_issue_15709():
assert powsimp(2*3**x/3) == 2*3**(x-1)
def test_issue_11981():
x, y = symbols('x y', commutative=False)
assert powsimp((x*y)**2 * (y*x)**2) == (x*y)**2 * (y*x)**2
|
97a75553ce4aed86a4044046f08d64cfd4c65af61f4b9dd86a10cdff5c17f439
|
from sympy import symbols, IndexedBase
from sympy.codegen.array_utils import (CodegenArrayContraction,
CodegenArrayTensorProduct, CodegenArrayDiagonal,
CodegenArrayPermuteDims, CodegenArrayElementwiseAdd,
_codegen_array_parse, _recognize_matrix_expression, _RecognizeMatOp,
_RecognizeMatMulLines, _unfold_recognized_expr,
parse_indexed_expression, recognize_matrix_expression,
_parse_matrix_expression)
from sympy import (MatrixSymbol, Sum)
from sympy.combinatorics import Permutation
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.matrices.expressions.matexpr import MatrixElement
from sympy.matrices import (Trace, MatAdd, MatMul, Transpose)
from sympy.utilities.pytest import raises, XFAIL
A, B = symbols("A B", cls=IndexedBase)
i, j, k, l, m, n = symbols("i j k l m n")
M = MatrixSymbol("M", k, k)
N = MatrixSymbol("N", k, k)
P = MatrixSymbol("P", k, k)
Q = MatrixSymbol("Q", k, k)
def test_codegen_array_contraction_construction():
cg = CodegenArrayContraction(A)
assert cg == A
s = Sum(A[i]*B[i], (i, 0, 3))
cg = parse_indexed_expression(s)
assert cg == CodegenArrayContraction(CodegenArrayTensorProduct(A, B), (0, 1))
cg = CodegenArrayContraction(CodegenArrayTensorProduct(A, B), (1, 0))
assert cg == CodegenArrayContraction(CodegenArrayTensorProduct(A, B), (0, 1))
expr = M*N
result = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2))
assert CodegenArrayContraction.from_MatMul(expr) == result
elem = expr[i, j]
assert parse_indexed_expression(elem) == result
expr = M*N*M
result = CodegenArrayContraction(CodegenArrayTensorProduct(M, N, M), (1, 2), (3, 4))
assert CodegenArrayContraction.from_MatMul(expr) == result
elem = expr[i, j]
result = CodegenArrayContraction(CodegenArrayTensorProduct(M, M, N), (1, 4), (2, 5))
cg = parse_indexed_expression(elem)
cg = cg.sort_args_by_name()
assert cg == result
def test_codegen_array_contraction_indices_types():
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (0, 1))
indtup = cg._get_contraction_tuples()
assert indtup == [[(0, 0), (0, 1)]]
assert cg._contraction_tuples_to_contraction_indices(cg.expr, indtup) == [(0, 1)]
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2))
indtup = cg._get_contraction_tuples()
assert indtup == [[(0, 1), (1, 0)]]
assert cg._contraction_tuples_to_contraction_indices(cg.expr, indtup) == [(1, 2)]
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, M, N), (1, 4), (2, 5))
indtup = cg._get_contraction_tuples()
assert indtup == [[(0, 1), (2, 0)], [(1, 0), (2, 1)]]
assert cg._contraction_tuples_to_contraction_indices(cg.expr, indtup) == [(1, 4), (2, 5)]
def test_codegen_array_recognize_matrix_mul_lines():
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M), (0, 1))
assert recognize_matrix_expression(cg) == Trace(M)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (0, 1), (2, 3))
assert recognize_matrix_expression(cg) == [Trace(M), Trace(N)]
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (0, 3), (1, 2))
assert recognize_matrix_expression(cg) == Trace(M*N)
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (0, 2), (1, 3))
assert recognize_matrix_expression(cg) == Trace(M*N.T)
cg = parse_indexed_expression((M*N*P)[i,j])
assert recognize_matrix_expression(cg) == M*N*P
cg = CodegenArrayContraction.from_MatMul(M*N*P)
assert recognize_matrix_expression(cg) == M*N*P
cg = parse_indexed_expression((M*N.T*P)[i,j])
assert recognize_matrix_expression(cg) == M*N.T*P
cg = CodegenArrayContraction.from_MatMul(M*N.T*P)
assert recognize_matrix_expression(cg) == M*N.T*P
cg = CodegenArrayContraction(CodegenArrayTensorProduct(M,N,P,Q), (1, 2), (5, 6))
assert recognize_matrix_expression(cg) == [M*N, P*Q]
expr = -2*M*N
elem = expr[i, j]
cg = parse_indexed_expression(elem)
assert recognize_matrix_expression(cg) == -2*M*N
def test_codegen_array_flatten():
# Flatten nested CodegenArrayTensorProduct objects:
expr1 = CodegenArrayTensorProduct(M, N)
expr2 = CodegenArrayTensorProduct(P, Q)
expr = CodegenArrayTensorProduct(expr1, expr2)
assert expr == CodegenArrayTensorProduct(M, N, P, Q)
assert expr.args == (M, N, P, Q)
# Flatten mixed CodegenArrayTensorProduct and CodegenArrayContraction objects:
cg1 = CodegenArrayContraction(expr1, (1, 2))
cg2 = CodegenArrayContraction(expr2, (0, 3))
expr = CodegenArrayTensorProduct(cg1, cg2)
assert expr == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (1, 2), (4, 7))
expr = CodegenArrayTensorProduct(M, cg1)
assert expr == CodegenArrayContraction(CodegenArrayTensorProduct(M, M, N), (3, 4))
# Flatten nested CodegenArrayContraction objects:
cgnested = CodegenArrayContraction(cg1, (0, 1))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (0, 3), (1, 2))
cgnested = CodegenArrayContraction(CodegenArrayTensorProduct(cg1, cg2), (0, 3))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (0, 6), (1, 2), (4, 7))
cg3 = CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (1, 3), (2, 4))
cgnested = CodegenArrayContraction(cg3, (0, 1))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (0, 5), (1, 3), (2, 4))
cgnested = CodegenArrayContraction(cg3, (0, 3), (1, 2))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (0, 7), (1, 3), (2, 4), (5, 6))
cg4 = CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (1, 5), (3, 7))
cgnested = CodegenArrayContraction(cg4, (0, 1))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (0, 2), (1, 5), (3, 7))
cgnested = CodegenArrayContraction(cg4, (0, 1), (2, 3))
assert cgnested == CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P, Q), (0, 2), (1, 5), (3, 7), (4, 6))
# Flatten nested CodegenArrayDiagonal objects:
cg1 = CodegenArrayDiagonal(expr1, (1, 2))
cg2 = CodegenArrayDiagonal(expr2, (0, 3))
cg3 = CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P, Q), (1, 3), (2, 4))
cg4 = CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P, Q), (1, 5), (3, 7))
cgnested = CodegenArrayDiagonal(cg1, (0, 1))
assert cgnested == CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N), (1, 2), (0, 3))
cgnested = CodegenArrayDiagonal(cg3, (1, 2))
assert cgnested == CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P, Q), (1, 3), (2, 4), (5, 6))
cgnested = CodegenArrayDiagonal(cg4, (1, 2))
assert cgnested == CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P, Q), (1, 5), (3, 7), (2, 4))
def test_codegen_array_parse():
expr = M[i, j]
assert _codegen_array_parse(expr) == (M, (i, j))
expr = M[i, j]*N[k, l]
assert _codegen_array_parse(expr) == (CodegenArrayTensorProduct(M, N), (i, j, k, l))
expr = M[i, j]*N[j, k]
assert _codegen_array_parse(expr) == (CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N), (1, 2)), (i, k, j))
expr = Sum(M[i, j]*N[j, k], (j, 0, k-1))
assert _codegen_array_parse(expr) == (CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2)), (i, k))
expr = M[i, j] + N[i, j]
assert _codegen_array_parse(expr) == (CodegenArrayElementwiseAdd(M, N), (i, j))
expr = M[i, j] + N[j, i]
assert _codegen_array_parse(expr) == (CodegenArrayElementwiseAdd(M, CodegenArrayPermuteDims(N, Permutation([1,0]))), (i, j))
expr = M[i, j] + M[j, i]
assert _codegen_array_parse(expr) == (CodegenArrayElementwiseAdd(M, CodegenArrayPermuteDims(M, Permutation([1,0]))), (i, j))
expr = (M*N*P)[i, j]
assert _codegen_array_parse(expr) == (CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P), (1, 2), (3, 4)), (i, j))
expr = expr.function # Disregard summation in previous expression
ret1, ret2 = _codegen_array_parse(expr)
assert ret1 == CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P), (1, 2), (3, 4))
assert str(ret2) == "(i, j, _i_1, _i_2)"
expr = KroneckerDelta(i, j)*M[i, k]
assert _codegen_array_parse(expr) == (M, ({i, j}, k))
expr = KroneckerDelta(i, j)*KroneckerDelta(j, k)*M[i, l]
assert _codegen_array_parse(expr) == (M, ({i, j, k}, l))
expr = KroneckerDelta(j, k)*(M[i, j]*N[k, l] + N[i, j]*M[k, l])
assert _codegen_array_parse(expr) == (CodegenArrayDiagonal(CodegenArrayElementwiseAdd(
CodegenArrayTensorProduct(M, N),
CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), Permutation(0, 2)(1, 3))
), (1, 2)), (i, l, frozenset({j, k})))
expr = KroneckerDelta(j, m)*KroneckerDelta(m, k)*(M[i, j]*N[k, l] + N[i, j]*M[k, l])
assert _codegen_array_parse(expr) == (CodegenArrayDiagonal(CodegenArrayElementwiseAdd(
CodegenArrayTensorProduct(M, N),
CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), Permutation(0, 2)(1, 3))
), (1, 2)), (i, l, frozenset({j, m, k})))
expr = KroneckerDelta(i, j)*KroneckerDelta(j, k)*KroneckerDelta(k,m)*M[i, 0]*KroneckerDelta(m, n)
assert _codegen_array_parse(expr) == (M, ({i,j,k,m,n}, 0))
expr = M[i, i]
assert _codegen_array_parse(expr) == (CodegenArrayDiagonal(M, (0, 1)), (i,))
def test_codegen_array_diagonal():
cg = CodegenArrayDiagonal(M, (1, 0))
assert cg == CodegenArrayDiagonal(M, (0, 1))
cg = CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P), (4, 1), (2, 0))
assert cg == CodegenArrayDiagonal(CodegenArrayTensorProduct(M, N, P), (1, 4), (0, 2))
def test_codegen_recognize_matrix_expression():
expr = CodegenArrayElementwiseAdd(M, CodegenArrayPermuteDims(M, [1, 0]))
rec = _recognize_matrix_expression(expr)
assert rec == _RecognizeMatOp(MatAdd, [M, _RecognizeMatOp(Transpose, [M])])
assert _unfold_recognized_expr(rec) == M + Transpose(M)
expr = M[i,j] + N[i,j]
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatOp(MatAdd, [M, N])
assert _unfold_recognized_expr(rec) == M + N
expr = M[i,j] + N[j,i]
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatOp(MatAdd, [M, _RecognizeMatOp(Transpose, [N])])
assert _unfold_recognized_expr(rec) == M + N.T
expr = M[i,j]*N[k,l] + N[i,j]*M[k,l]
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatOp(MatAdd, [_RecognizeMatMulLines([M, N]), _RecognizeMatMulLines([N, M])])
#assert _unfold_recognized_expr(rec) == TensorProduct(M, N) + TensorProduct(N, M) maybe?
expr = (M*N*P)[i, j]
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatMulLines([_RecognizeMatOp(MatMul, [M, N, P])])
assert _unfold_recognized_expr(rec) == M*N*P
expr = Sum(M[i,j]*(N*P)[j,m], (j, 0, k-1))
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatOp(MatMul, [M, N, P])
assert _unfold_recognized_expr(rec) == M*N*P
expr = Sum((P[j, m] + P[m, j])*(M[i,j]*N[m,n] + N[i,j]*M[m,n]), (j, 0, k-1), (m, 0, k-1))
p1, p2 = _codegen_array_parse(expr)
rec = _recognize_matrix_expression(p1)
assert rec == _RecognizeMatOp(MatAdd, [
_RecognizeMatOp(MatMul, [M, _RecognizeMatOp(MatAdd, [P, _RecognizeMatOp(Transpose, [P])]), N]),
_RecognizeMatOp(MatMul, [N, _RecognizeMatOp(MatAdd, [P, _RecognizeMatOp(Transpose, [P])]), M])
])
assert _unfold_recognized_expr(rec) == M*(P + P.T)*N + N*(P + P.T)*M
def test_codegen_array_shape():
expr = CodegenArrayTensorProduct(M, N, P, Q)
assert expr.shape == (k, k, k, k, k, k, k, k)
Z = MatrixSymbol("Z", m, n)
expr = CodegenArrayTensorProduct(M, Z)
assert expr.shape == (k, k, m, n)
expr2 = CodegenArrayContraction(expr, (0, 1))
assert expr2.shape == (m, n)
expr2 = CodegenArrayDiagonal(expr, (0, 1))
assert expr2.shape == (m, n, k)
exprp = CodegenArrayPermuteDims(expr, [2, 1, 3, 0])
assert exprp.shape == (m, k, n, k)
expr3 = CodegenArrayTensorProduct(N, Z)
expr2 = CodegenArrayElementwiseAdd(expr, expr3)
assert expr2.shape == (k, k, m, n)
# Contraction along axes with discordant dimensions:
raises(ValueError, lambda: CodegenArrayContraction(expr, (1, 2)))
# Also diagonal needs the same dimensions:
raises(ValueError, lambda: CodegenArrayDiagonal(expr, (1, 2)))
def test_codegen_array_parse_out_of_bounds():
expr = Sum(M[i, i], (i, 0, 4))
raises(ValueError, lambda: parse_indexed_expression(expr))
expr = Sum(M[i, i], (i, 0, k))
raises(ValueError, lambda: parse_indexed_expression(expr))
expr = Sum(M[i, i], (i, 1, k-1))
raises(ValueError, lambda: parse_indexed_expression(expr))
expr = Sum(M[i, j]*N[j,m], (j, 0, 4))
raises(ValueError, lambda: parse_indexed_expression(expr))
expr = Sum(M[i, j]*N[j,m], (j, 0, k))
raises(ValueError, lambda: parse_indexed_expression(expr))
expr = Sum(M[i, j]*N[j,m], (j, 1, k-1))
raises(ValueError, lambda: parse_indexed_expression(expr))
def test_codegen_permutedims_sink():
cg = CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [0, 1, 3, 2])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayTensorProduct(M, CodegenArrayPermuteDims(N, [1, 0]))
assert recognize_matrix_expression(sunk) == [M, N.T]
cg = CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [1, 0, 3, 2])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayTensorProduct(CodegenArrayPermuteDims(M, [1, 0]), CodegenArrayPermuteDims(N, [1, 0]))
assert recognize_matrix_expression(sunk) == [M.T, N.T]
cg = CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [3, 2, 1, 0])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayTensorProduct(CodegenArrayPermuteDims(N, [1, 0]), CodegenArrayPermuteDims(M, [1, 0]))
assert recognize_matrix_expression(sunk) == [N.T, M.T]
cg = CodegenArrayPermuteDims(CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2)), [1, 0])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayContraction(CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [[0, 3]]), (1, 2))
cg = CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N), [1, 0, 3, 2])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayTensorProduct(CodegenArrayPermuteDims(M, [1, 0]), CodegenArrayPermuteDims(N, [1, 0]))
cg = CodegenArrayPermuteDims(CodegenArrayContraction(CodegenArrayTensorProduct(M, N, P), (1, 2), (3, 4)), [1, 0])
sunk = cg.nest_permutation()
assert sunk == CodegenArrayContraction(CodegenArrayPermuteDims(CodegenArrayTensorProduct(M, N, P), [[0, 5]]), (1, 2), (3, 4))
sunk2 = sunk.expr.nest_permutation()
def test_parsing_of_matrix_expressions():
expr = M*N
assert _parse_matrix_expression(expr) == CodegenArrayContraction(CodegenArrayTensorProduct(M, N), (1, 2))
expr = Transpose(M)
assert _parse_matrix_expression(expr) == CodegenArrayPermuteDims(M, [1, 0])
expr = M*Transpose(N)
assert _parse_matrix_expression(expr) == CodegenArrayContraction(CodegenArrayTensorProduct(M, CodegenArrayPermuteDims(N, [1, 0])), (1, 2))
def test_special_matrices():
a = MatrixSymbol("a", k, 1)
b = MatrixSymbol("b", k, 1)
expr = a.T*b
elem = expr[0, 0]
cg = parse_indexed_expression(elem)
assert cg == CodegenArrayContraction(CodegenArrayTensorProduct(a, b), (0, 2))
assert recognize_matrix_expression(cg) == a.T*b
|
c566347c8e4965a90cb2c147b2fe70a60034f45be4bd4e32fd3edcd6c6e7948e
|
from __future__ import print_function, division
from sympy.core import sympify
from sympy.core.add import Add
from sympy.core.function import Lambda, Function, ArgumentIndexError
from sympy.core.cache import cacheit
from sympy.core.numbers import Integer
from sympy.core.power import Pow
from sympy.core.singleton import S
from sympy.core.symbol import Wild, Dummy
from sympy.core.mul import Mul
from sympy.core.logic import fuzzy_not
from sympy.functions.combinatorial.factorials import factorial
from sympy.functions.elementary.miscellaneous import sqrt
from sympy.ntheory import multiplicity, perfect_power
from sympy.core.compatibility import range
# NOTE IMPORTANT
# The series expansion code in this file is an important part of the gruntz
# algorithm for determining limits. _eval_nseries has to return a generalized
# power series with coefficients in C(log(x), log).
# In more detail, the result of _eval_nseries(self, x, n) must be
# c_0*x**e_0 + ... (finitely many terms)
# where e_i are numbers (not necessarily integers) and c_i involve only
# numbers, the function log, and log(x). [This also means it must not contain
# log(x(1+p)), this *has* to be expanded to log(x)+log(1+p) if x.is_positive and
# p.is_positive.]
class ExpBase(Function):
unbranched = True
def inverse(self, argindex=1):
"""
Returns the inverse function of ``exp(x)``.
"""
return log
def as_numer_denom(self):
"""
Returns this with a positive exponent as a 2-tuple (a fraction).
Examples
========
>>> from sympy.functions import exp
>>> from sympy.abc import x
>>> exp(-x).as_numer_denom()
(1, exp(x))
>>> exp(x).as_numer_denom()
(exp(x), 1)
"""
# this should be the same as Pow.as_numer_denom wrt
# exponent handling
exp = self.exp
neg_exp = exp.is_negative
if not neg_exp and not (-exp).is_negative:
neg_exp = _coeff_isneg(exp)
if neg_exp:
return S.One, self.func(-exp)
return self, S.One
@property
def exp(self):
"""
Returns the exponent of the function.
"""
return self.args[0]
def as_base_exp(self):
"""
Returns the 2-tuple (base, exponent).
"""
return self.func(1), Mul(*self.args)
def _eval_conjugate(self):
return self.func(self.args[0].conjugate())
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_infinite:
if arg.is_negative:
return True
if arg.is_positive:
return False
if arg.is_finite:
return True
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if s.exp is S.Zero:
return True
elif s.exp.is_rational and fuzzy_not(s.exp.is_zero):
return False
else:
return s.is_rational
def _eval_is_zero(self):
return (self.args[0] is S.NegativeInfinity)
def _eval_power(self, other):
"""exp(arg)**e -> exp(arg*e) if assumptions allow it.
"""
b, e = self.as_base_exp()
return Pow._eval_power(Pow(b, e, evaluate=False), other)
def _eval_expand_power_exp(self, **hints):
arg = self.args[0]
if arg.is_Add and arg.is_commutative:
expr = 1
for x in arg.args:
expr *= self.func(x)
return expr
return self.func(arg)
class exp_polar(ExpBase):
r"""
Represent a 'polar number' (see g-function Sphinx documentation).
``exp_polar`` represents the function
`Exp: \mathbb{C} \rightarrow \mathcal{S}`, sending the complex number
`z = a + bi` to the polar number `r = exp(a), \theta = b`. It is one of
the main functions to construct polar numbers.
>>> from sympy import exp_polar, pi, I, exp
The main difference is that polar numbers don't "wrap around" at `2 \pi`:
>>> exp(2*pi*I)
1
>>> exp_polar(2*pi*I)
exp_polar(2*I*pi)
apart from that they behave mostly like classical complex numbers:
>>> exp_polar(2)*exp_polar(3)
exp_polar(5)
See also
========
sympy.simplify.simplify.powsimp
sympy.functions.elementary.complexes.polar_lift
sympy.functions.elementary.complexes.periodic_argument
sympy.functions.elementary.complexes.principal_branch
"""
is_polar = True
is_comparable = False # cannot be evalf'd
def _eval_Abs(self): # Abs is never a polar number
from sympy.functions.elementary.complexes import re
return exp(re(self.args[0]))
def _eval_evalf(self, prec):
""" Careful! any evalf of polar numbers is flaky """
from sympy import im, pi, re
i = im(self.args[0])
try:
bad = (i <= -pi or i > pi)
except TypeError:
bad = True
if bad:
return self # cannot evalf for this argument
res = exp(self.args[0])._eval_evalf(prec)
if i > 0 and im(res) < 0:
# i ~ pi, but exp(I*i) evaluated to argument slightly bigger than pi
return re(res)
return res
def _eval_power(self, other):
return self.func(self.args[0]*other)
def _eval_is_real(self):
if self.args[0].is_real:
return True
def as_base_exp(self):
# XXX exp_polar(0) is special!
if self.args[0] == 0:
return self, S(1)
return ExpBase.as_base_exp(self)
class exp(ExpBase):
"""
The exponential function, :math:`e^x`.
See Also
========
log
"""
def fdiff(self, argindex=1):
"""
Returns the first derivative of this function.
"""
if argindex == 1:
return self
else:
raise ArgumentIndexError(self, argindex)
def _eval_refine(self, assumptions):
from sympy.assumptions import ask, Q
arg = self.args[0]
if arg.is_Mul:
Ioo = S.ImaginaryUnit*S.Infinity
if arg in [Ioo, -Ioo]:
return S.NaN
coeff = arg.as_coefficient(S.Pi*S.ImaginaryUnit)
if coeff:
if ask(Q.integer(2*coeff)):
if ask(Q.even(coeff)):
return S.One
elif ask(Q.odd(coeff)):
return S.NegativeOne
elif ask(Q.even(coeff + S.Half)):
return -S.ImaginaryUnit
elif ask(Q.odd(coeff + S.Half)):
return S.ImaginaryUnit
@classmethod
def eval(cls, arg):
from sympy.assumptions import ask, Q
from sympy.calculus import AccumBounds
from sympy.sets.setexpr import SetExpr
from sympy.matrices.matrices import MatrixBase
if arg.is_Number:
if arg is S.NaN:
return S.NaN
elif arg is S.Zero:
return S.One
elif arg is S.One:
return S.Exp1
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Zero
elif arg is S.ComplexInfinity:
return S.NaN
elif isinstance(arg, log):
return arg.args[0]
elif isinstance(arg, AccumBounds):
return AccumBounds(exp(arg.min), exp(arg.max))
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
elif arg.is_Mul:
if arg.is_number or arg.is_Symbol:
coeff = arg.coeff(S.Pi*S.ImaginaryUnit)
if coeff:
if ask(Q.integer(2*coeff)):
if ask(Q.even(coeff)):
return S.One
elif ask(Q.odd(coeff)):
return S.NegativeOne
elif ask(Q.even(coeff + S.Half)):
return -S.ImaginaryUnit
elif ask(Q.odd(coeff + S.Half)):
return S.ImaginaryUnit
# Warning: code in risch.py will be very sensitive to changes
# in this (see DifferentialExtension).
# look for a single log factor
coeff, terms = arg.as_coeff_Mul()
# but it can't be multiplied by oo
if coeff in [S.NegativeInfinity, S.Infinity]:
return None
coeffs, log_term = [coeff], None
for term in Mul.make_args(terms):
if isinstance(term, log):
if log_term is None:
log_term = term.args[0]
else:
return None
elif term.is_comparable:
coeffs.append(term)
else:
return None
return log_term**Mul(*coeffs) if log_term else None
elif arg.is_Add:
out = []
add = []
for a in arg.args:
if a is S.One:
add.append(a)
continue
newa = cls(a)
if isinstance(newa, cls):
add.append(a)
else:
out.append(newa)
if out:
return Mul(*out)*cls(Add(*add), evaluate=False)
elif isinstance(arg, MatrixBase):
return arg.exp()
@property
def base(self):
"""
Returns the base of the exponential function.
"""
return S.Exp1
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms):
"""
Calculates the next term in the Taylor series expansion.
"""
if n < 0:
return S.Zero
if n == 0:
return S.One
x = sympify(x)
if previous_terms:
p = previous_terms[-1]
if p is not None:
return p * x / n
return x**n/factorial(n)
def as_real_imag(self, deep=True, **hints):
"""
Returns this function as a 2-tuple representing a complex number.
Examples
========
>>> from sympy import I
>>> from sympy.abc import x
>>> from sympy.functions import exp
>>> exp(x).as_real_imag()
(exp(re(x))*cos(im(x)), exp(re(x))*sin(im(x)))
>>> exp(1).as_real_imag()
(E, 0)
>>> exp(I).as_real_imag()
(cos(1), sin(1))
>>> exp(1+I).as_real_imag()
(E*cos(1), E*sin(1))
See Also
========
sympy.functions.elementary.complexes.re
sympy.functions.elementary.complexes.im
"""
import sympy
re, im = self.args[0].as_real_imag()
if deep:
re = re.expand(deep, **hints)
im = im.expand(deep, **hints)
cos, sin = sympy.cos(im), sympy.sin(im)
return (exp(re)*cos, exp(re)*sin)
def _eval_subs(self, old, new):
# keep processing of power-like args centralized in Pow
if old.is_Pow: # handle (exp(3*log(x))).subs(x**2, z) -> z**(3/2)
old = exp(old.exp*log(old.base))
elif old is S.Exp1 and new.is_Function:
old = exp
if isinstance(old, exp) or old is S.Exp1:
f = lambda a: Pow(*a.as_base_exp(), evaluate=False) if (
a.is_Pow or isinstance(a, exp)) else a
return Pow._eval_subs(f(self), f(old), new)
if old is exp and not new.is_Function:
return new**self.exp._subs(old, new)
return Function._eval_subs(self, old, new)
def _eval_is_real(self):
if self.args[0].is_real:
return True
elif self.args[0].is_imaginary:
arg2 = -S(2) * S.ImaginaryUnit * self.args[0] / S.Pi
return arg2.is_even
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if fuzzy_not(self.exp.is_zero):
if self.exp.is_algebraic:
return False
elif (self.exp/S.Pi).is_rational:
return False
else:
return s.is_algebraic
def _eval_is_positive(self):
if self.args[0].is_real:
return not self.args[0] is S.NegativeInfinity
elif self.args[0].is_imaginary:
arg2 = -S.ImaginaryUnit * self.args[0] / S.Pi
return arg2.is_even
def _eval_nseries(self, x, n, logx):
# NOTE Please see the comment at the beginning of this file, labelled
# IMPORTANT.
from sympy import limit, oo, Order, powsimp
arg = self.args[0]
arg_series = arg._eval_nseries(x, n=n, logx=logx)
if arg_series.is_Order:
return 1 + arg_series
arg0 = limit(arg_series.removeO(), x, 0)
if arg0 in [-oo, oo]:
return self
t = Dummy("t")
exp_series = exp(t)._taylor(t, n)
o = exp_series.getO()
exp_series = exp_series.removeO()
r = exp(arg0)*exp_series.subs(t, arg_series - arg0)
r += Order(o.expr.subs(t, (arg_series - arg0)), x)
r = r.expand()
return powsimp(r, deep=True, combine='exp')
def _taylor(self, x, n):
from sympy import Order
l = []
g = None
for i in range(n):
g = self.taylor_term(i, self.args[0], g)
g = g.nseries(x, n=n)
l.append(g)
return Add(*l) + Order(x**n, x)
def _eval_as_leading_term(self, x):
from sympy import Order
arg = self.args[0]
if arg.is_Add:
return Mul(*[exp(f).as_leading_term(x) for f in arg.args])
arg = self.args[0].as_leading_term(x)
if Order(1, x).contains(arg):
return S.One
return exp(arg)
def _eval_rewrite_as_sin(self, arg, **kwargs):
from sympy import sin
I = S.ImaginaryUnit
return sin(I*arg + S.Pi/2) - I*sin(I*arg)
def _eval_rewrite_as_cos(self, arg, **kwargs):
from sympy import cos
I = S.ImaginaryUnit
return cos(I*arg) + I*cos(I*arg + S.Pi/2)
def _eval_rewrite_as_tanh(self, arg, **kwargs):
from sympy import tanh
return (1 + tanh(arg/2))/(1 - tanh(arg/2))
def _eval_rewrite_as_sqrt(self, arg, **kwargs):
from sympy.functions.elementary.trigonometric import sin, cos
if arg.is_Mul:
coeff = arg.coeff(S.Pi*S.ImaginaryUnit)
if coeff and coeff.is_number:
cosine, sine = cos(S.Pi*coeff), sin(S.Pi*coeff)
if not isinstance(cosine, cos) and not isinstance (sine, sin):
return cosine + S.ImaginaryUnit*sine
def _eval_rewrite_as_Pow(self, arg, **kwargs):
if arg.is_Mul:
logs = [a for a in arg.args if isinstance(a, log) and len(a.args) == 1]
if logs:
return Pow(logs[0].args[0], arg.coeff(logs[0]))
class log(Function):
r"""
The natural logarithm function `\ln(x)` or `\log(x)`.
Logarithms are taken with the natural base, `e`. To get
a logarithm of a different base ``b``, use ``log(x, b)``,
which is essentially short-hand for ``log(x)/log(b)``.
See Also
========
exp
"""
def fdiff(self, argindex=1):
"""
Returns the first derivative of the function.
"""
if argindex == 1:
return 1/self.args[0]
else:
raise ArgumentIndexError(self, argindex)
def inverse(self, argindex=1):
r"""
Returns `e^x`, the inverse function of `\log(x)`.
"""
return exp
@classmethod
def eval(cls, arg, base=None):
from sympy import unpolarify
from sympy.calculus import AccumBounds
from sympy.sets.setexpr import SetExpr
arg = sympify(arg)
if base is not None:
base = sympify(base)
if base == 1:
if arg == 1:
return S.NaN
else:
return S.ComplexInfinity
try:
# handle extraction of powers of the base now
# or else expand_log in Mul would have to handle this
n = multiplicity(base, arg)
if n:
den = base**n
if den.is_Integer:
return n + log(arg // den) / log(base)
else:
return n + log(arg / den) / log(base)
else:
return log(arg)/log(base)
except ValueError:
pass
if base is not S.Exp1:
return cls(arg)/cls(base)
else:
return cls(arg)
if arg.is_Number:
if arg is S.Zero:
return S.ComplexInfinity
elif arg is S.One:
return S.Zero
elif arg is S.Infinity:
return S.Infinity
elif arg is S.NegativeInfinity:
return S.Infinity
elif arg is S.NaN:
return S.NaN
elif arg.is_Rational and arg.p == 1:
return -cls(arg.q)
if arg is S.ComplexInfinity:
return S.ComplexInfinity
if isinstance(arg, exp) and arg.args[0].is_real:
return arg.args[0]
elif isinstance(arg, exp_polar):
return unpolarify(arg.exp)
elif isinstance(arg, AccumBounds):
if arg.min.is_positive:
return AccumBounds(log(arg.min), log(arg.max))
else:
return
elif isinstance(arg, SetExpr):
return arg._eval_func(cls)
if arg.is_number:
if arg.is_negative:
return S.Pi * S.ImaginaryUnit + cls(-arg)
elif arg is S.ComplexInfinity:
return S.ComplexInfinity
elif arg is S.Exp1:
return S.One
# don't autoexpand Pow or Mul (see the issue 3351):
if not arg.is_Add:
coeff = arg.as_coefficient(S.ImaginaryUnit)
if coeff is not None:
if coeff is S.Infinity:
return S.Infinity
elif coeff is S.NegativeInfinity:
return S.Infinity
elif coeff.is_Rational:
if coeff.is_nonnegative:
return S.Pi * S.ImaginaryUnit * S.Half + cls(coeff)
else:
return -S.Pi * S.ImaginaryUnit * S.Half + cls(-coeff)
def as_base_exp(self):
"""
Returns this function in the form (base, exponent).
"""
return self, S.One
@staticmethod
@cacheit
def taylor_term(n, x, *previous_terms): # of log(1+x)
r"""
Returns the next term in the Taylor series expansion of `\log(1+x)`.
"""
from sympy import powsimp
if n < 0:
return S.Zero
x = sympify(x)
if n == 0:
return x
if previous_terms:
p = previous_terms[-1]
if p is not None:
return powsimp((-n) * p * x / (n + 1), deep=True, combine='exp')
return (1 - 2*(n % 2)) * x**(n + 1)/(n + 1)
def _eval_expand_log(self, deep=True, **hints):
from sympy import unpolarify, expand_log
from sympy.concrete import Sum, Product
force = hints.get('force', False)
if (len(self.args) == 2):
return expand_log(self.func(*self.args), deep=deep, force=force)
arg = self.args[0]
if arg.is_Integer:
# remove perfect powers
p = perfect_power(int(arg))
if p is not False:
return p[1]*self.func(p[0])
elif arg.is_Rational:
return log(arg.p) - log(arg.q)
elif arg.is_Mul:
expr = []
nonpos = []
for x in arg.args:
if force or x.is_positive or x.is_polar:
a = self.func(x)
if isinstance(a, log):
expr.append(self.func(x)._eval_expand_log(**hints))
else:
expr.append(a)
elif x.is_negative:
a = self.func(-x)
expr.append(a)
nonpos.append(S.NegativeOne)
else:
nonpos.append(x)
return Add(*expr) + log(Mul(*nonpos))
elif arg.is_Pow or isinstance(arg, exp):
if force or (arg.exp.is_real and (arg.base.is_positive or ((arg.exp+1)
.is_positive and (arg.exp-1).is_nonpositive))) or arg.base.is_polar:
b = arg.base
e = arg.exp
a = self.func(b)
if isinstance(a, log):
return unpolarify(e) * a._eval_expand_log(**hints)
else:
return unpolarify(e) * a
elif isinstance(arg, Product):
if arg.function.is_positive:
return Sum(log(arg.function), *arg.limits)
return self.func(arg)
def _eval_simplify(self, ratio, measure, rational, inverse):
from sympy.simplify.simplify import expand_log, simplify, inversecombine
if (len(self.args) == 2):
return simplify(self.func(*self.args), ratio=ratio, measure=measure,
rational=rational, inverse=inverse)
expr = self.func(simplify(self.args[0], ratio=ratio, measure=measure,
rational=rational, inverse=inverse))
if inverse:
expr = inversecombine(expr)
expr = expand_log(expr, deep=True)
return min([expr, self], key=measure)
def as_real_imag(self, deep=True, **hints):
"""
Returns this function as a complex coordinate.
Examples
========
>>> from sympy import I
>>> from sympy.abc import x
>>> from sympy.functions import log
>>> log(x).as_real_imag()
(log(Abs(x)), arg(x))
>>> log(I).as_real_imag()
(0, pi/2)
>>> log(1 + I).as_real_imag()
(log(sqrt(2)), pi/4)
>>> log(I*x).as_real_imag()
(log(Abs(x)), arg(I*x))
"""
from sympy import Abs, arg
if deep:
abs = Abs(self.args[0].expand(deep, **hints))
arg = arg(self.args[0].expand(deep, **hints))
else:
abs = Abs(self.args[0])
arg = arg(self.args[0])
if hints.get('log', False): # Expand the log
hints['complex'] = False
return (log(abs).expand(deep, **hints), arg)
else:
return (log(abs), arg)
def _eval_is_rational(self):
s = self.func(*self.args)
if s.func == self.func:
if (self.args[0] - 1).is_zero:
return True
if s.args[0].is_rational and fuzzy_not((self.args[0] - 1).is_zero):
return False
else:
return s.is_rational
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if (self.args[0] - 1).is_zero:
return True
elif fuzzy_not((self.args[0] - 1).is_zero):
if self.args[0].is_algebraic:
return False
else:
return s.is_algebraic
def _eval_is_real(self):
return self.args[0].is_positive
def _eval_is_finite(self):
arg = self.args[0]
if arg.is_zero:
return False
return arg.is_finite
def _eval_is_positive(self):
return (self.args[0] - 1).is_positive
def _eval_is_zero(self):
return (self.args[0] - 1).is_zero
def _eval_is_nonnegative(self):
return (self.args[0] - 1).is_nonnegative
def _eval_nseries(self, x, n, logx):
# NOTE Please see the comment at the beginning of this file, labelled
# IMPORTANT.
from sympy import cancel, Order
if not logx:
logx = log(x)
if self.args[0] == x:
return logx
arg = self.args[0]
k, l = Wild("k"), Wild("l")
r = arg.match(k*x**l)
if r is not None:
k, l = r[k], r[l]
if l != 0 and not l.has(x) and not k.has(x):
r = log(k) + l*logx # XXX true regardless of assumptions?
return r
# TODO new and probably slow
s = self.args[0].nseries(x, n=n, logx=logx)
while s.is_Order:
n += 1
s = self.args[0].nseries(x, n=n, logx=logx)
a, b = s.leadterm(x)
p = cancel(s/(a*x**b) - 1)
g = None
l = []
for i in range(n + 2):
g = log.taylor_term(i, p, g)
g = g.nseries(x, n=n, logx=logx)
l.append(g)
return log(a) + b*logx + Add(*l) + Order(p**n, x)
def _eval_as_leading_term(self, x):
arg = self.args[0].as_leading_term(x)
if arg is S.One:
return (self.args[0] - 1).as_leading_term(x)
return self.func(arg)
class LambertW(Function):
r"""
The Lambert W function `W(z)` is defined as the inverse
function of `w \exp(w)` [1]_.
In other words, the value of `W(z)` is such that `z = W(z) \exp(W(z))`
for any complex number `z`. The Lambert W function is a multivalued
function with infinitely many branches `W_k(z)`, indexed by
`k \in \mathbb{Z}`. Each branch gives a different solution `w`
of the equation `z = w \exp(w)`.
The Lambert W function has two partially real branches: the
principal branch (`k = 0`) is real for real `z > -1/e`, and the
`k = -1` branch is real for `-1/e < z < 0`. All branches except
`k = 0` have a logarithmic singularity at `z = 0`.
Examples
========
>>> from sympy import LambertW
>>> LambertW(1.2)
0.635564016364870
>>> LambertW(1.2, -1).n()
-1.34747534407696 - 4.41624341514535*I
>>> LambertW(-1).is_real
False
References
==========
.. [1] https://en.wikipedia.org/wiki/Lambert_W_function
"""
@classmethod
def eval(cls, x, k=None):
if k is S.Zero:
return cls(x)
elif k is None:
k = S.Zero
if k is S.Zero:
if x is S.Zero:
return S.Zero
if x is S.Exp1:
return S.One
if x == -1/S.Exp1:
return S.NegativeOne
if x == -log(2)/2:
return -log(2)
if x is S.Infinity:
return S.Infinity
if fuzzy_not(k.is_zero):
if x is S.Zero:
return S.NegativeInfinity
if k is S.NegativeOne:
if x == -S.Pi/2:
return -S.ImaginaryUnit*S.Pi/2
elif x == -1/S.Exp1:
return S.NegativeOne
elif x == -2*exp(-2):
return -Integer(2)
def fdiff(self, argindex=1):
"""
Return the first derivative of this function.
"""
x = self.args[0]
if len(self.args) == 1:
if argindex == 1:
return LambertW(x)/(x*(1 + LambertW(x)))
else:
k = self.args[1]
if argindex == 1:
return LambertW(x, k)/(x*(1 + LambertW(x, k)))
raise ArgumentIndexError(self, argindex)
def _eval_is_real(self):
x = self.args[0]
if len(self.args) == 1:
k = S.Zero
else:
k = self.args[1]
if k.is_zero:
if (x + 1/S.Exp1).is_positive:
return True
elif (x + 1/S.Exp1).is_nonpositive:
return False
elif (k + 1).is_zero:
if x.is_negative and (x + 1/S.Exp1).is_positive:
return True
elif x.is_nonpositive or (x + 1/S.Exp1).is_nonnegative:
return False
elif fuzzy_not(k.is_zero) and fuzzy_not((k + 1).is_zero):
if x.is_real:
return False
def _eval_is_algebraic(self):
s = self.func(*self.args)
if s.func == self.func:
if fuzzy_not(self.args[0].is_zero) and self.args[0].is_algebraic:
return False
else:
return s.is_algebraic
from sympy.core.function import _coeff_isneg
|
d4d95523fe9c6f3123c503d1bf06f81de63cd576272e7c62fc43c3a55c4a281a
|
from sympy import (
symbols, log, ln, Float, nan, oo, zoo, I, pi, E, exp, Symbol,
LambertW, sqrt, Rational, expand_log, S, sign, conjugate, refine,
sin, cos, sinh, cosh, tanh, exp_polar, re, Function, simplify,
AccumBounds, MatrixSymbol, Pow)
from sympy.abc import x, y, z
def test_exp_values():
k = Symbol('k', integer=True)
assert exp(nan) == nan
assert exp(oo) == oo
assert exp(-oo) == 0
assert exp(0) == 1
assert exp(1) == E
assert exp(-1 + x).as_base_exp() == (S.Exp1, x - 1)
assert exp(1 + x).as_base_exp() == (S.Exp1, x + 1)
assert exp(pi*I/2) == I
assert exp(pi*I) == -1
assert exp(3*pi*I/2) == -I
assert exp(2*pi*I) == 1
assert refine(exp(pi*I*2*k)) == 1
assert refine(exp(pi*I*2*(k + Rational(1, 2)))) == -1
assert refine(exp(pi*I*2*(k + Rational(1, 4)))) == I
assert refine(exp(pi*I*2*(k + Rational(3, 4)))) == -I
assert exp(log(x)) == x
assert exp(2*log(x)) == x**2
assert exp(pi*log(x)) == x**pi
assert exp(17*log(x) + E*log(y)) == x**17 * y**E
assert exp(x*log(x)) != x**x
assert exp(sin(x)*log(x)) != x
assert exp(3*log(x) + oo*x) == exp(oo*x) * x**3
assert exp(4*log(x)*log(y) + 3*log(x)) == x**3 * exp(4*log(x)*log(y))
def test_exp_log():
x = Symbol("x", real=True)
assert log(exp(x)) == x
assert exp(log(x)) == x
assert log(x).inverse() == exp
assert exp(x).inverse() == log
y = Symbol("y", polar=True)
assert log(exp_polar(z)) == z
assert exp(log(y)) == y
def test_exp_expand():
e = exp(log(Rational(2))*(1 + x) - log(Rational(2))*x)
assert e.expand() == 2
assert exp(x + y) != exp(x)*exp(y)
assert exp(x + y).expand() == exp(x)*exp(y)
def test_exp__as_base_exp():
assert exp(x).as_base_exp() == (E, x)
assert exp(2*x).as_base_exp() == (E, 2*x)
assert exp(x*y).as_base_exp() == (E, x*y)
assert exp(-x).as_base_exp() == (E, -x)
# Pow( *expr.as_base_exp() ) == expr invariant should hold
assert E**x == exp(x)
assert E**(2*x) == exp(2*x)
assert E**(x*y) == exp(x*y)
assert exp(x).base is S.Exp1
assert exp(x).exp == x
def test_exp_infinity():
assert exp(I*y) != nan
assert refine(exp(I*oo)) == nan
assert refine(exp(-I*oo)) == nan
assert exp(y*I*oo) != nan
assert exp(zoo) == nan
def test_exp_subs():
x = Symbol('x')
e = (exp(3*log(x), evaluate=False)) # evaluates to x**3
assert e.subs(x**3, y**3) == e
assert e.subs(x**2, 5) == e
assert (x**3).subs(x**2, y) != y**(3/S(2))
assert exp(exp(x) + exp(x**2)).subs(exp(exp(x)), y) == y * exp(exp(x**2))
assert exp(x).subs(E, y) == y**x
x = symbols('x', real=True)
assert exp(5*x).subs(exp(7*x), y) == y**Rational(5, 7)
assert exp(2*x + 7).subs(exp(3*x), y) == y**Rational(2, 3) * exp(7)
x = symbols('x', positive=True)
assert exp(3*log(x)).subs(x**2, y) == y**Rational(3, 2)
# differentiate between E and exp
assert exp(exp(x + E)).subs(exp, 3) == 3**(3**(x + E))
assert exp(exp(x + E)).subs(E, 3) == 3**(3**(x + 3))
assert exp(3).subs(E, sin) == sin(3)
def test_exp_conjugate():
assert conjugate(exp(x)) == exp(conjugate(x))
def test_exp_rewrite():
from sympy.concrete.summations import Sum
assert exp(x).rewrite(sin) == sinh(x) + cosh(x)
assert exp(x*I).rewrite(cos) == cos(x) + I*sin(x)
assert exp(1).rewrite(cos) == sinh(1) + cosh(1)
assert exp(1).rewrite(sin) == sinh(1) + cosh(1)
assert exp(1).rewrite(sin) == sinh(1) + cosh(1)
assert exp(x).rewrite(tanh) == (1 + tanh(x/2))/(1 - tanh(x/2))
assert exp(pi*I/4).rewrite(sqrt) == sqrt(2)/2 + sqrt(2)*I/2
assert exp(pi*I/3).rewrite(sqrt) == S(1)/2 + sqrt(3)*I/2
assert exp(x*log(y)).rewrite(Pow) == y**x
assert exp(log(x)*log(y)).rewrite(Pow) in [x**log(y), y**log(x)]
assert exp(log(log(x))*y).rewrite(Pow) == log(x)**y
n = Symbol('n', integer=True)
assert Sum((exp(pi*I/2)/2)**n, (n, 0, oo)).rewrite(sqrt).doit() == S(4)/5 + 2*I/5
assert Sum((exp(pi*I/4)/2)**n, (n, 0, oo)).rewrite(sqrt).doit() == 1/(1 - sqrt(2)*(1 + I)/4)
assert Sum((exp(pi*I/3)/2)**n, (n, 0, oo)).rewrite(sqrt).doit() == 1/(S(3)/4 - sqrt(3)*I/4)
def test_exp_leading_term():
assert exp(x).as_leading_term(x) == 1
assert exp(1/x).as_leading_term(x) == exp(1/x)
assert exp(2 + x).as_leading_term(x) == exp(2)
def test_exp_taylor_term():
x = symbols('x')
assert exp(x).taylor_term(1, x) == x
assert exp(x).taylor_term(3, x) == x**3/6
assert exp(x).taylor_term(4, x) == x**4/24
def test_exp_MatrixSymbol():
A = MatrixSymbol("A", 2, 2)
assert exp(A).has(exp)
def test_log_values():
assert log(nan) == nan
assert log(oo) == oo
assert log(-oo) == oo
assert log(zoo) == zoo
assert log(-zoo) == zoo
assert log(0) == zoo
assert log(1) == 0
assert log(-1) == I*pi
assert log(E) == 1
assert log(-E).expand() == 1 + I*pi
assert log(pi) == log(pi)
assert log(-pi).expand() == log(pi) + I*pi
assert log(17) == log(17)
assert log(-17) == log(17) + I*pi
assert log(I) == I*pi/2
assert log(-I) == -I*pi/2
assert log(17*I) == I*pi/2 + log(17)
assert log(-17*I).expand() == -I*pi/2 + log(17)
assert log(oo*I) == oo
assert log(-oo*I) == oo
assert log(0, 2) == zoo
assert log(0, 5) == zoo
assert exp(-log(3))**(-1) == 3
assert log(S.Half) == -log(2)
assert log(2*3).func is log
assert log(2*3**2).func is log
def test_log_base():
assert log(1, 2) == 0
assert log(2, 2) == 1
assert log(3, 2) == log(3)/log(2)
assert log(6, 2) == 1 + log(3)/log(2)
assert log(6, 3) == 1 + log(2)/log(3)
assert log(2**3, 2) == 3
assert log(3**3, 3) == 3
assert log(5, 1) == zoo
assert log(1, 1) == nan
assert log(Rational(2, 3), 10) == log(S(2)/3)/log(10)
assert log(Rational(2, 3), Rational(1, 3)) == -log(2)/log(3) + 1
assert log(Rational(2, 3), Rational(2, 5)) == \
log(S(2)/3)/log(S(2)/5)
def test_log_symbolic():
assert log(x, exp(1)) == log(x)
assert log(exp(x)) != x
assert log(x, exp(1)) == log(x)
assert log(x*y) != log(x) + log(y)
assert log(x/y).expand() != log(x) - log(y)
assert log(x/y).expand(force=True) == log(x) - log(y)
assert log(x**y).expand() != y*log(x)
assert log(x**y).expand(force=True) == y*log(x)
assert log(x, 2) == log(x)/log(2)
assert log(E, 2) == 1/log(2)
p, q = symbols('p,q', positive=True)
r = Symbol('r', real=True)
assert log(p**2) != 2*log(p)
assert log(p**2).expand() == 2*log(p)
assert log(x**2).expand() != 2*log(x)
assert log(p**q) != q*log(p)
assert log(exp(p)) == p
assert log(p*q) != log(p) + log(q)
assert log(p*q).expand() == log(p) + log(q)
assert log(-sqrt(3)) == log(sqrt(3)) + I*pi
assert log(-exp(p)) != p + I*pi
assert log(-exp(x)).expand() != x + I*pi
assert log(-exp(r)).expand() == r + I*pi
assert log(x**y) != y*log(x)
assert (log(x**-5)**-1).expand() != -1/log(x)/5
assert (log(p**-5)**-1).expand() == -1/log(p)/5
assert log(-x).func is log and log(-x).args[0] == -x
assert log(-p).func is log and log(-p).args[0] == -p
def test_exp_assumptions():
r = Symbol('r', real=True)
i = Symbol('i', imaginary=True)
for e in exp, exp_polar:
assert e(x).is_real is None
assert e(x).is_imaginary is None
assert e(i).is_real is None
assert e(i).is_imaginary is None
assert e(r).is_real is True
assert e(r).is_imaginary is False
assert e(re(x)).is_real is True
assert e(re(x)).is_imaginary is False
assert exp(0, evaluate=False).is_algebraic
a = Symbol('a', algebraic=True)
an = Symbol('an', algebraic=True, nonzero=True)
r = Symbol('r', rational=True)
rn = Symbol('rn', rational=True, nonzero=True)
assert exp(a).is_algebraic is None
assert exp(an).is_algebraic is False
assert exp(pi*r).is_algebraic is None
assert exp(pi*rn).is_algebraic is False
def test_exp_AccumBounds():
assert exp(AccumBounds(1, 2)) == AccumBounds(E, E**2)
def test_log_assumptions():
p = symbols('p', positive=True)
n = symbols('n', negative=True)
z = symbols('z', zero=True)
x = symbols('x', infinite=True, positive=True)
assert log(z).is_positive is False
assert log(x).is_positive is True
assert log(2) > 0
assert log(1, evaluate=False).is_zero
assert log(1 + z).is_zero
assert log(p).is_zero is None
assert log(n).is_zero is False
assert log(0.5).is_negative is True
assert log(exp(p) + 1).is_positive
assert log(1, evaluate=False).is_algebraic
assert log(42, evaluate=False).is_algebraic is False
assert log(1 + z).is_rational
def test_log_hashing():
assert x != log(log(x))
assert hash(x) != hash(log(log(x)))
assert log(x) != log(log(log(x)))
e = 1/log(log(x) + log(log(x)))
assert e.base.func is log
e = 1/log(log(x) + log(log(log(x))))
assert e.base.func is log
e = log(log(x))
assert e.func is log
assert not x.func is log
assert hash(log(log(x))) != hash(x)
assert e != x
def test_log_sign():
assert sign(log(2)) == 1
def test_log_expand_complex():
assert log(1 + I).expand(complex=True) == log(2)/2 + I*pi/4
assert log(1 - sqrt(2)).expand(complex=True) == log(sqrt(2) - 1) + I*pi
def test_log_apply_evalf():
value = (log(3)/log(2) - 1).evalf()
assert value.epsilon_eq(Float("0.58496250072115618145373"))
def test_log_expand():
w = Symbol("w", positive=True)
e = log(w**(log(5)/log(3)))
assert e.expand() == log(5)/log(3) * log(w)
x, y, z = symbols('x,y,z', positive=True)
assert log(x*(y + z)).expand(mul=False) == log(x) + log(y + z)
assert log(log(x**2)*log(y*z)).expand() in [log(2*log(x)*log(y) +
2*log(x)*log(z)), log(log(x)*log(z) + log(y)*log(x)) + log(2),
log((log(y) + log(z))*log(x)) + log(2)]
assert log(x**log(x**2)).expand(deep=False) == log(x)*log(x**2)
assert log(x**log(x**2)).expand() == 2*log(x)**2
assert (log(x*(y + z))*(x + y)), expand(mul=True, log=True) == y*log(
x) + y*log(y + z) + z*log(x) + z*log(y + z)
x, y = symbols('x,y')
assert log(x*y).expand(force=True) == log(x) + log(y)
assert log(x**y).expand(force=True) == y*log(x)
assert log(exp(x)).expand(force=True) == x
# there's generally no need to expand out logs since this requires
# factoring and if simplification is sought, it's cheaper to put
# logs together than it is to take them apart.
assert log(2*3**2).expand() != 2*log(3) + log(2)
def test_log_simplify():
x = Symbol("x", positive=True)
assert log(x**2).expand() == 2*log(x)
assert expand_log(log(x**(2 + log(2)))) == (2 + log(2))*log(x)
z = Symbol('z')
assert log(sqrt(z)).expand() == log(z)/2
assert expand_log(log(z**(log(2) - 1))) == (log(2) - 1)*log(z)
assert log(z**(-1)).expand() != -log(z)
assert log(z**(x/(x+1))).expand() == x*log(z)/(x + 1)
def test_log_AccumBounds():
assert log(AccumBounds(1, E)) == AccumBounds(0, 1)
def test_lambertw():
k = Symbol('k')
assert LambertW(x, 0) == LambertW(x)
assert LambertW(x, 0, evaluate=False) != LambertW(x)
assert LambertW(0) == 0
assert LambertW(E) == 1
assert LambertW(-1/E) == -1
assert LambertW(-log(2)/2) == -log(2)
assert LambertW(oo) == oo
assert LambertW(0, 1) == -oo
assert LambertW(0, 42) == -oo
assert LambertW(-pi/2, -1) == -I*pi/2
assert LambertW(-1/E, -1) == -1
assert LambertW(-2*exp(-2), -1) == -2
assert LambertW(x**2).diff(x) == 2*LambertW(x**2)/x/(1 + LambertW(x**2))
assert LambertW(x, k).diff(x) == LambertW(x, k)/x/(1 + LambertW(x, k))
assert LambertW(sqrt(2)).evalf(30).epsilon_eq(
Float("0.701338383413663009202120278965", 30), 1e-29)
assert re(LambertW(2, -1)).evalf().epsilon_eq(Float("-0.834310366631110"))
assert LambertW(-1).is_real is False # issue 5215
assert LambertW(2, evaluate=False).is_real
p = Symbol('p', positive=True)
assert LambertW(p, evaluate=False).is_real
assert LambertW(p - 1, evaluate=False).is_real is None
assert LambertW(-p - 2/S.Exp1, evaluate=False).is_real is False
assert LambertW(S.Half, -1, evaluate=False).is_real is False
assert LambertW(-S.One/10, -1, evaluate=False).is_real
assert LambertW(-10, -1, evaluate=False).is_real is False
assert LambertW(-2, 2, evaluate=False).is_real is False
assert LambertW(0, evaluate=False).is_algebraic
na = Symbol('na', nonzero=True, algebraic=True)
assert LambertW(na).is_algebraic is False
def test_issue_5673():
e = LambertW(-1)
assert e.is_comparable is False
assert e.is_positive is not True
e2 = 1 - 1/(1 - exp(-1000))
assert e.is_positive is not True
e3 = -2 + exp(exp(LambertW(log(2)))*LambertW(log(2)))
assert e3.is_nonzero is not True
def test_exp_expand_NC():
A, B, C = symbols('A,B,C', commutative=False)
assert exp(A + B).expand() == exp(A + B)
assert exp(A + B + C).expand() == exp(A + B + C)
assert exp(x + y).expand() == exp(x)*exp(y)
assert exp(x + y + z).expand() == exp(x)*exp(y)*exp(z)
def test_as_numer_denom():
n = symbols('n', negative=True)
assert exp(x).as_numer_denom() == (exp(x), 1)
assert exp(-x).as_numer_denom() == (1, exp(x))
assert exp(-2*x).as_numer_denom() == (1, exp(2*x))
assert exp(-2).as_numer_denom() == (1, exp(2))
assert exp(n).as_numer_denom() == (1, exp(-n))
assert exp(-n).as_numer_denom() == (exp(-n), 1)
assert exp(-I*x).as_numer_denom() == (1, exp(I*x))
assert exp(-I*n).as_numer_denom() == (1, exp(I*n))
assert exp(-n).as_numer_denom() == (exp(-n), 1)
def test_polar():
x, y = symbols('x y', polar=True)
assert abs(exp_polar(I*4)) == 1
assert abs(exp_polar(0)) == 1
assert abs(exp_polar(2 + 3*I)) == exp(2)
assert exp_polar(I*10).n() == exp_polar(I*10)
assert log(exp_polar(z)) == z
assert log(x*y).expand() == log(x) + log(y)
assert log(x**z).expand() == z*log(x)
assert exp_polar(3).exp == 3
# Compare exp(1.0*pi*I).
assert (exp_polar(1.0*pi*I).n(n=5)).as_real_imag()[1] >= 0
assert exp_polar(0).is_rational is True # issue 8008
def test_log_product():
from sympy.abc import n, m
i, j = symbols('i,j', positive=True, integer=True)
x, y = symbols('x,y', positive=True)
from sympy.concrete import Product, Sum
f, g = Function('f'), Function('g')
assert simplify(log(Product(x**i, (i, 1, n)))) == Sum(i*log(x), (i, 1, n))
assert simplify(log(Product(x**i*y**j, (i, 1, n), (j, 1, m)))) == \
log(Product(x**i*y**j, (i, 1, n), (j, 1, m)))
expr = log(Product(-2, (n, 0, 4)))
assert simplify(expr) == expr
def test_issue_8866():
assert simplify(log(x, 10, evaluate=False)) == simplify(log(x, 10))
assert expand_log(log(x, 10, evaluate=False)) == expand_log(log(x, 10))
y = Symbol('y', positive=True)
l1 = log(exp(y), exp(10))
b1 = log(exp(y), exp(5))
l2 = log(exp(y), exp(10), evaluate=False)
b2 = log(exp(y), exp(5), evaluate=False)
assert simplify(log(l1, b1)) == simplify(log(l2, b2))
assert expand_log(log(l1, b1)) == expand_log(log(l2, b2))
def test_issue_9116():
n = Symbol('n', positive=True, integer=True)
assert ln(n).is_nonnegative is True
assert log(n).is_nonnegative is True
|
018009429356c1e359034ba20cfd9e980efb1f3eba71a418d25087c9a9ef859e
|
from sympy import (acos, acosh, asinh, atan, cos, Derivative, diff, dsolve,
Dummy, Eq, Ne, erf, erfi, exp, Function, I, Integral, LambertW, log, O, pi,
Rational, rootof, S, simplify, sin, sqrt, Subs, Symbol, tan, asin, sinh,
Piecewise, symbols, Poly, sec, Ei, re, im)
from sympy.solvers.ode import (_undetermined_coefficients_match,
checkodesol, classify_ode, classify_sysode, constant_renumber,
constantsimp, homogeneous_order, infinitesimals, checkinfsol,
checksysodesol, solve_ics, dsolve, get_numbered_constants)
from sympy.solvers.deutils import ode_order
from sympy.utilities.pytest import XFAIL, skip, raises, slow, ON_TRAVIS
C0, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 = symbols('C0:11')
u, x, y, z = symbols('u,x:z', real=True)
f = Function('f')
g = Function('g')
h = Function('h')
# Note: the tests below may fail (but still be correct) if ODE solver,
# the integral engine, solve(), or even simplify() changes. Also, in
# differently formatted solutions, the arbitrary constants might not be
# equal. Using specific hints in tests can help to avoid this.
# Tests of order higher than 1 should run the solutions through
# constant_renumber because it will normalize it (constant_renumber causes
# dsolve() to return different results on different machines)
def test_linear_2eq_order1():
x, y, z = symbols('x, y, z', cls=Function)
k, l, m, n = symbols('k, l, m, n', Integer=True)
t = Symbol('t')
x0, y0 = symbols('x0, y0', cls=Function)
eq1 = (Eq(diff(x(t),t), 9*y(t)), Eq(diff(y(t),t), 12*x(t)))
sol1 = [Eq(x(t), 9*C1*exp(6*sqrt(3)*t) + 9*C2*exp(-6*sqrt(3)*t)), \
Eq(y(t), 6*sqrt(3)*C1*exp(6*sqrt(3)*t) - 6*sqrt(3)*C2*exp(-6*sqrt(3)*t))]
assert checksysodesol(eq1, sol1) == (True, [0, 0])
eq2 = (Eq(diff(x(t),t), 2*x(t) + 4*y(t)), Eq(diff(y(t),t), 12*x(t) + 41*y(t)))
sol2 = [Eq(x(t), 4*C1*exp(t*(sqrt(1713)/2 + S(43)/2)) + 4*C2*exp(t*(-sqrt(1713)/2 + S(43)/2))), \
Eq(y(t), C1*(S(39)/2 + sqrt(1713)/2)*exp(t*(sqrt(1713)/2 + S(43)/2)) + \
C2*(-sqrt(1713)/2 + S(39)/2)*exp(t*(-sqrt(1713)/2 + S(43)/2)))]
assert checksysodesol(eq2, sol2) == (True, [0, 0])
eq3 = (Eq(diff(x(t),t), x(t) + y(t)), Eq(diff(y(t),t), -2*x(t) + 2*y(t)))
sol3 = [Eq(x(t), (C1*cos(sqrt(7)*t/2) + C2*sin(sqrt(7)*t/2))*exp(3*t/2)), \
Eq(y(t), (C1*(-sqrt(7)*sin(sqrt(7)*t/2)/2 + cos(sqrt(7)*t/2)/2) + \
C2*(sin(sqrt(7)*t/2)/2 + sqrt(7)*cos(sqrt(7)*t/2)/2))*exp(3*t/2))]
assert checksysodesol(eq3, sol3) == (True, [0, 0])
eq4 = (Eq(diff(x(t),t), x(t) + y(t) + 9), Eq(diff(y(t),t), 2*x(t) + 5*y(t) + 23))
sol4 = [Eq(x(t), C1*exp(t*(sqrt(6) + 3)) + C2*exp(t*(-sqrt(6) + 3)) - S(22)/3), \
Eq(y(t), C1*(2 + sqrt(6))*exp(t*(sqrt(6) + 3)) + C2*(-sqrt(6) + 2)*exp(t*(-sqrt(6) + 3)) - S(5)/3)]
assert checksysodesol(eq4, sol4) == (True, [0, 0])
eq5 = (Eq(diff(x(t),t), x(t) + y(t) + 81), Eq(diff(y(t),t), -2*x(t) + y(t) + 23))
sol5 = [Eq(x(t), (C1*cos(sqrt(2)*t) + C2*sin(sqrt(2)*t))*exp(t) - S(58)/3), \
Eq(y(t), (-sqrt(2)*C1*sin(sqrt(2)*t) + sqrt(2)*C2*cos(sqrt(2)*t))*exp(t) - S(185)/3)]
assert checksysodesol(eq5, sol5) == (True, [0, 0])
eq6 = (Eq(diff(x(t),t), 5*t*x(t) + 2*y(t)), Eq(diff(y(t),t), 2*x(t) + 5*t*y(t)))
sol6 = [Eq(x(t), (C1*exp(2*t) + C2*exp(-2*t))*exp(S(5)/2*t**2)), \
Eq(y(t), (C1*exp(2*t) - C2*exp(-2*t))*exp(S(5)/2*t**2))]
s = dsolve(eq6)
assert checksysodesol(eq6, sol6) == (True, [0, 0])
eq7 = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), -t**2*x(t) + 5*t*y(t)))
sol7 = [Eq(x(t), (C1*cos((t**3)/3) + C2*sin((t**3)/3))*exp(S(5)/2*t**2)), \
Eq(y(t), (-C1*sin((t**3)/3) + C2*cos((t**3)/3))*exp(S(5)/2*t**2))]
assert checksysodesol(eq7, sol7) == (True, [0, 0])
eq8 = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), -t**2*x(t) + (5*t+9*t**2)*y(t)))
sol8 = [Eq(x(t), (C1*exp((sqrt(77)/2 + S(9)/2)*(t**3)/3) + \
C2*exp((-sqrt(77)/2 + S(9)/2)*(t**3)/3))*exp(S(5)/2*t**2)), \
Eq(y(t), (C1*(sqrt(77)/2 + S(9)/2)*exp((sqrt(77)/2 + S(9)/2)*(t**3)/3) + \
C2*(-sqrt(77)/2 + S(9)/2)*exp((-sqrt(77)/2 + S(9)/2)*(t**3)/3))*exp(S(5)/2*t**2))]
assert checksysodesol(eq8, sol8) == (True, [0, 0])
eq10 = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), (1-t**2)*x(t) + (5*t+9*t**2)*y(t)))
sol10 = [Eq(x(t), C1*x0(t) + C2*x0(t)*Integral(t**2*exp(Integral(5*t, t))*exp(Integral(9*t**2 + 5*t, t))/x0(t)**2, t)), \
Eq(y(t), C1*y0(t) + C2*(y0(t)*Integral(t**2*exp(Integral(5*t, t))*exp(Integral(9*t**2 + 5*t, t))/x0(t)**2, t) + \
exp(Integral(5*t, t))*exp(Integral(9*t**2 + 5*t, t))/x0(t)))]
s = dsolve(eq10)
assert s == sol10 # too complicated to test with subs and simplify
def test_linear_2eq_order1_nonhomog_linear():
e = [Eq(diff(f(x), x), f(x) + g(x) + 5*x),
Eq(diff(g(x), x), f(x) - g(x))]
raises(NotImplementedError, lambda: dsolve(e))
def test_linear_2eq_order1_nonhomog():
# Note: once implemented, add some tests esp. with resonance
e = [Eq(diff(f(x), x), f(x) + exp(x)),
Eq(diff(g(x), x), f(x) + g(x) + x*exp(x))]
raises(NotImplementedError, lambda: dsolve(e))
def test_linear_2eq_order1_type2_degen():
e = [Eq(diff(f(x), x), f(x) + 5),
Eq(diff(g(x), x), f(x) + 7)]
s1 = [Eq(f(x), C1*exp(x) - 5), Eq(g(x), C1*exp(x) - C2 + 2*x - 5)]
assert checksysodesol(e, s1) == (True, [0, 0])
def test_dsolve_linear_2eq_order1_diag_triangular():
e = [Eq(diff(f(x), x), f(x)),
Eq(diff(g(x), x), g(x))]
s1 = [Eq(f(x), C1*exp(x)), Eq(g(x), C2*exp(x))]
assert checksysodesol(e, s1) == (True, [0, 0])
e = [Eq(diff(f(x), x), 2*f(x)),
Eq(diff(g(x), x), 3*f(x) + 7*g(x))]
s1 = [Eq(f(x), -5*C2*exp(2*x)),
Eq(g(x), 5*C1*exp(7*x) + 3*C2*exp(2*x))]
assert checksysodesol(e, s1) == (True, [0, 0])
def test_sysode_linear_2eq_order1_type1_D_lt_0():
e = [Eq(diff(f(x), x), -9*I*f(x) - 4*g(x)),
Eq(diff(g(x), x), -4*I*g(x))]
s1 = [Eq(f(x), -4*C1*exp(-4*I*x) - 4*C2*exp(-9*I*x)), \
Eq(g(x), 5*I*C1*exp(-4*I*x))]
assert checksysodesol(e, s1) == (True, [0, 0])
def test_sysode_linear_2eq_order1_type1_D_lt_0_b_eq_0():
e = [Eq(diff(f(x), x), -9*I*f(x)),
Eq(diff(g(x), x), -4*I*g(x))]
s1 = [Eq(f(x), -5*I*C2*exp(-9*I*x)), Eq(g(x), 5*I*C1*exp(-4*I*x))]
assert checksysodesol(e, s1) == (True, [0, 0])
def test_sysode_linear_2eq_order1_many_zeros():
t = Symbol('t')
corner_cases = [(0, 0, 0, 0), (1, 0, 0, 0), (0, 1, 0, 0),
(0, 0, 1, 0), (0, 0, 0, 1), (1, 0, 0, I),
(I, 0, 0, -I), (0, I, 0, 0), (0, I, I, 0)]
s1 = [[Eq(f(t), C1), Eq(g(t), C2)],
[Eq(f(t), C1*exp(t)), Eq(g(t), -C2)],
[Eq(f(t), C1 + C2*t), Eq(g(t), C2)],
[Eq(f(t), C2), Eq(g(t), C1 + C2*t)],
[Eq(f(t), -C2), Eq(g(t), C1*exp(t))],
[Eq(f(t), C1*(1 - I)*exp(t)), Eq(g(t), C2*(-1 + I)*exp(I*t))],
[Eq(f(t), 2*I*C1*exp(I*t)), Eq(g(t), -2*I*C2*exp(-I*t))],
[Eq(f(t), I*C1 + I*C2*t), Eq(g(t), C2)],
[Eq(f(t), I*C1*exp(I*t) + I*C2*exp(-I*t)), \
Eq(g(t), I*C1*exp(I*t) - I*C2*exp(-I*t))]
]
for r, sol in zip(corner_cases, s1):
eq = [Eq(diff(f(t), t), r[0]*f(t) + r[1]*g(t)),
Eq(diff(g(t), t), r[2]*f(t) + r[3]*g(t))]
assert checksysodesol(eq, sol) == (True, [0, 0])
def test_dsolve_linsystem_symbol_piecewise():
u = Symbol('u') # XXX it's more complicated with real u
eq = (Eq(diff(f(x), x), 2*f(x) + g(x)),
Eq(diff(g(x), x), u*f(x)))
s1 = [Eq(f(x), Piecewise((C1*exp(x*(sqrt(4*u + 4)/2 + 1)) +
C2*exp(x*(-sqrt(4*u + 4)/2 + 1)), Ne(4*u + 4, 0)), ((C1 + C2*(x +
Piecewise((0, Eq(sqrt(4*u + 4)/2 + 1, 2)), (1/(-sqrt(4*u + 4)/2 + 1),
True))))*exp(x*(sqrt(4*u + 4)/2 + 1)), True))), Eq(g(x),
Piecewise((C1*(sqrt(4*u + 4)/2 - 1)*exp(x*(sqrt(4*u + 4)/2 + 1)) +
C2*(-sqrt(4*u + 4)/2 - 1)*exp(x*(-sqrt(4*u + 4)/2 + 1)), Ne(4*u + 4,
0)), ((C1*(sqrt(4*u + 4)/2 - 1) + C2*(x*(sqrt(4*u + 4)/2 - 1) +
Piecewise((1, Eq(sqrt(4*u + 4)/2 + 1, 2)), (0,
True))))*exp(x*(sqrt(4*u + 4)/2 + 1)), True)))]
s = dsolve(eq)
assert s == s1
s = [(l.lhs, l.rhs) for l in s]
for v in [0, 7, -42, 5*I, 3 + 4*I]:
assert eq[0].subs(s).subs(u, v).doit().simplify()
assert eq[1].subs(s).subs(u, v).doit().simplify()
# example from https://groups.google.com/d/msg/sympy/xmzoqW6tWaE/sf0bgQrlCgAJ
i, r1, c1, r2, c2, t = symbols('i, r1, c1, r2, c2, t')
x1 = Function('x1')
x2 = Function('x2')
eq1 = r1*c1*Derivative(x1(t), t) + x1(t) - x2(t) - r1*i
eq2 = r2*c1*Derivative(x1(t), t) + r2*c2*Derivative(x2(t), t) + x2(t) - r2*i
sol = dsolve((eq1, eq2))
# it's a complicated formula, was previously a TypeError
assert all(s.has(Piecewise) for s in sol)
def test_linear_2eq_order2():
x, y, z = symbols('x, y, z', cls=Function)
k, l, m, n = symbols('k, l, m, n', Integer=True)
t, l = symbols('t, l')
x0, y0 = symbols('x0, y0', cls=Function)
eq1 = (Eq(diff(x(t),t,t), 5*x(t) + 43*y(t)), Eq(diff(y(t),t,t), x(t) + 9*y(t)))
sol1 = [Eq(x(t), 43*C1*exp(t*rootof(l**4 - 14*l**2 + 2, 0)) + 43*C2*exp(t*rootof(l**4 - 14*l**2 + 2, 1)) + \
43*C3*exp(t*rootof(l**4 - 14*l**2 + 2, 2)) + 43*C4*exp(t*rootof(l**4 - 14*l**2 + 2, 3))), \
Eq(y(t), C1*(rootof(l**4 - 14*l**2 + 2, 0)**2 - 5)*exp(t*rootof(l**4 - 14*l**2 + 2, 0)) + \
C2*(rootof(l**4 - 14*l**2 + 2, 1)**2 - 5)*exp(t*rootof(l**4 - 14*l**2 + 2, 1)) + \
C3*(rootof(l**4 - 14*l**2 + 2, 2)**2 - 5)*exp(t*rootof(l**4 - 14*l**2 + 2, 2)) + \
C4*(rootof(l**4 - 14*l**2 + 2, 3)**2 - 5)*exp(t*rootof(l**4 - 14*l**2 + 2, 3)))]
assert dsolve(eq1) == sol1
eq2 = (Eq(diff(x(t),t,t), 8*x(t)+3*y(t)+31), Eq(diff(y(t),t,t), 9*x(t)+7*y(t)+12))
sol2 = [Eq(x(t), 3*C1*exp(t*rootof(l**4 - 15*l**2 + 29, 0)) + 3*C2*exp(t*rootof(l**4 - 15*l**2 + 29, 1)) + \
3*C3*exp(t*rootof(l**4 - 15*l**2 + 29, 2)) + 3*C4*exp(t*rootof(l**4 - 15*l**2 + 29, 3)) - S(181)/29), \
Eq(y(t), C1*(rootof(l**4 - 15*l**2 + 29, 0)**2 - 8)*exp(t*rootof(l**4 - 15*l**2 + 29, 0)) + \
C2*(rootof(l**4 - 15*l**2 + 29, 1)**2 - 8)*exp(t*rootof(l**4 - 15*l**2 + 29, 1)) + \
C3*(rootof(l**4 - 15*l**2 + 29, 2)**2 - 8)*exp(t*rootof(l**4 - 15*l**2 + 29, 2)) + \
C4*(rootof(l**4 - 15*l**2 + 29, 3)**2 - 8)*exp(t*rootof(l**4 - 15*l**2 + 29, 3)) + S(183)/29)]
assert dsolve(eq2) == sol2
eq3 = (Eq(diff(x(t),t,t) - 9*diff(y(t),t) + 7*x(t),0), Eq(diff(y(t),t,t) + 9*diff(x(t),t) + 7*y(t),0))
sol3 = [Eq(x(t), C1*cos(t*(S(9)/2 + sqrt(109)/2)) + C2*sin(t*(S(9)/2 + sqrt(109)/2)) + C3*cos(t*(-sqrt(109)/2 + S(9)/2)) + \
C4*sin(t*(-sqrt(109)/2 + S(9)/2))), Eq(y(t), -C1*sin(t*(S(9)/2 + sqrt(109)/2)) + C2*cos(t*(S(9)/2 + sqrt(109)/2)) - \
C3*sin(t*(-sqrt(109)/2 + S(9)/2)) + C4*cos(t*(-sqrt(109)/2 + S(9)/2)))]
assert dsolve(eq3) == sol3
eq4 = (Eq(diff(x(t),t,t), 9*t*diff(y(t),t)-9*y(t)), Eq(diff(y(t),t,t),7*t*diff(x(t),t)-7*x(t)))
sol4 = [Eq(x(t), C3*t + t*Integral((9*C1*exp(3*sqrt(7)*t**2/2) + 9*C2*exp(-3*sqrt(7)*t**2/2))/t**2, t)), \
Eq(y(t), C4*t + t*Integral((3*sqrt(7)*C1*exp(3*sqrt(7)*t**2/2) - 3*sqrt(7)*C2*exp(-3*sqrt(7)*t**2/2))/t**2, t))]
assert dsolve(eq4) == sol4
eq5 = (Eq(diff(x(t),t,t), (log(t)+t**2)*diff(x(t),t)+(log(t)+t**2)*3*diff(y(t),t)), Eq(diff(y(t),t,t), \
(log(t)+t**2)*2*diff(x(t),t)+(log(t)+t**2)*9*diff(y(t),t)))
sol5 = [Eq(x(t), -sqrt(22)*(C1*Integral(exp((-sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) + C2 - \
C3*Integral(exp((sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) - C4 - \
(sqrt(22) + 5)*(C1*Integral(exp((-sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) + C2) + \
(-sqrt(22) + 5)*(C3*Integral(exp((sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) + C4))/88), \
Eq(y(t), -sqrt(22)*(C1*Integral(exp((-sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) + \
C2 - C3*Integral(exp((sqrt(22) + 5)*Integral(t**2 + log(t), t)), t) - C4)/44)]
assert dsolve(eq5) == sol5
eq6 = (Eq(diff(x(t),t,t), log(t)*t*diff(y(t),t) - log(t)*y(t)), Eq(diff(y(t),t,t), log(t)*t*diff(x(t),t) - log(t)*x(t)))
sol6 = [Eq(x(t), C3*t + t*Integral((C1*exp(Integral(t*log(t), t)) + \
C2*exp(-Integral(t*log(t), t)))/t**2, t)), Eq(y(t), C4*t + t*Integral((C1*exp(Integral(t*log(t), t)) - \
C2*exp(-Integral(t*log(t), t)))/t**2, t))]
assert dsolve(eq6) == sol6
eq7 = (Eq(diff(x(t),t,t), log(t)*(t*diff(x(t),t) - x(t)) + exp(t)*(t*diff(y(t),t) - y(t))), \
Eq(diff(y(t),t,t), (t**2)*(t*diff(x(t),t) - x(t)) + (t)*(t*diff(y(t),t) - y(t))))
sol7 = [Eq(x(t), C3*t + t*Integral((C1*x0(t) + C2*x0(t)*Integral(t*exp(t)*exp(Integral(t**2, t))*\
exp(Integral(t*log(t), t))/x0(t)**2, t))/t**2, t)), Eq(y(t), C4*t + t*Integral((C1*y0(t) + \
C2*(y0(t)*Integral(t*exp(t)*exp(Integral(t**2, t))*exp(Integral(t*log(t), t))/x0(t)**2, t) + \
exp(Integral(t**2, t))*exp(Integral(t*log(t), t))/x0(t)))/t**2, t))]
assert dsolve(eq7) == sol7
eq8 = (Eq(diff(x(t),t,t), t*(4*x(t) + 9*y(t))), Eq(diff(y(t),t,t), t*(12*x(t) - 6*y(t))))
sol8 = ("[Eq(x(t), -sqrt(133)*((-sqrt(133) - 1)*(C2*(133*t**8/24 - t**3/6 + sqrt(133)*t**3/2 + 1) + "
"C1*t*(sqrt(133)*t**4/6 - t**3/12 + 1) + O(t**6)) - (-1 + sqrt(133))*(C2*(-sqrt(133)*t**3/6 - t**3/6 + 1) + "
"C1*t*(-sqrt(133)*t**3/12 - t**3/12 + 1) + O(t**6)) - 4*C2*(133*t**8/24 - t**3/6 + sqrt(133)*t**3/2 + 1) + "
"4*C2*(-sqrt(133)*t**3/6 - t**3/6 + 1) - 4*C1*t*(sqrt(133)*t**4/6 - t**3/12 + 1) + "
"4*C1*t*(-sqrt(133)*t**3/12 - t**3/12 + 1) + O(t**6))/3192), Eq(y(t), -sqrt(133)*(-C2*(133*t**8/24 - t**3/6 + "
"sqrt(133)*t**3/2 + 1) + C2*(-sqrt(133)*t**3/6 - t**3/6 + 1) - C1*t*(sqrt(133)*t**4/6 - t**3/12 + 1) + "
"C1*t*(-sqrt(133)*t**3/12 - t**3/12 + 1) + O(t**6))/266)]")
assert str(dsolve(eq8)) == sol8
eq9 = (Eq(diff(x(t),t,t), t*(4*diff(x(t),t) + 9*diff(y(t),t))), Eq(diff(y(t),t,t), t*(12*diff(x(t),t) - 6*diff(y(t),t))))
sol9 = [Eq(x(t), -sqrt(133)*(4*C1*Integral(exp((-sqrt(133) - 1)*Integral(t, t)), t) + 4*C2 - \
4*C3*Integral(exp((-1 + sqrt(133))*Integral(t, t)), t) - 4*C4 - (-1 + sqrt(133))*(C1*Integral(exp((-sqrt(133) - \
1)*Integral(t, t)), t) + C2) + (-sqrt(133) - 1)*(C3*Integral(exp((-1 + sqrt(133))*Integral(t, t)), t) + \
C4))/3192), Eq(y(t), -sqrt(133)*(C1*Integral(exp((-sqrt(133) - 1)*Integral(t, t)), t) + C2 - \
C3*Integral(exp((-1 + sqrt(133))*Integral(t, t)), t) - C4)/266)]
assert dsolve(eq9) == sol9
eq10 = (t**2*diff(x(t),t,t) + 3*t*diff(x(t),t) + 4*t*diff(y(t),t) + 12*x(t) + 9*y(t), \
t**2*diff(y(t),t,t) + 2*t*diff(x(t),t) - 5*t*diff(y(t),t) + 15*x(t) + 8*y(t))
sol10 = [Eq(x(t), -C1*(-2*sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 13 + 2*sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + \
346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))))*exp((-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 + sqrt(-284/sqrt(-346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)))/2)*log(t)) - \
C2*(-2*sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
13 - 2*sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))))*exp((-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 - sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)*log(t)) - C3*t**(1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2 + sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)*(2*sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 13 + 2*sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))) - C4*t**(-sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2 + 1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))/2)*(-2*sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))) + 2*sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 13)), Eq(y(t), C1*(-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 14 + (-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 + sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)**2 + sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))))*exp((-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 + sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)*log(t)) + C2*(-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 14 - sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))) + (-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 - sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)**2)*exp((-sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))/2 + 1 - sqrt(-284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) - 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)*log(t)) + C3*t**(1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + \
2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2 + sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)*(sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))) + 14 + (1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3))/2 + sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + 346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)))/2)**2) + C4*t**(-sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + \
346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)))/2 + 1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2)*(-sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + \
8 + 346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))) + (-sqrt(-2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3) + 8 + \
346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 284/sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)))/2 + 1 + sqrt(-346/(3*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + \
4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3))/2)**2 + sqrt(-346/(3*(S(4333)/4 + \
5*sqrt(70771857)/36)**(S(1)/3)) + 4 + 2*(S(4333)/4 + 5*sqrt(70771857)/36)**(S(1)/3)) + 14))]
assert dsolve(eq10) == sol10
def test_linear_3eq_order1():
x, y, z = symbols('x, y, z', cls=Function)
t = Symbol('t')
eq1 = (Eq(diff(x(t),t), 21*x(t)), Eq(diff(y(t),t), 17*x(t)+3*y(t)), Eq(diff(z(t),t), 5*x(t)+7*y(t)+9*z(t)))
sol1 = [Eq(x(t), C1*exp(21*t)), Eq(y(t), 17*C1*exp(21*t)/18 + C2*exp(3*t)), \
Eq(z(t), 209*C1*exp(21*t)/216 - 7*C2*exp(3*t)/6 + C3*exp(9*t))]
assert checksysodesol(eq1, sol1) == (True, [0, 0, 0])
eq2 = (Eq(diff(x(t),t),3*y(t)-11*z(t)),Eq(diff(y(t),t),7*z(t)-3*x(t)),Eq(diff(z(t),t),11*x(t)-7*y(t)))
sol2 = [Eq(x(t), 7*C0 + sqrt(179)*C1*cos(sqrt(179)*t) + (77*C1/3 + 130*C2/3)*sin(sqrt(179)*t)), \
Eq(y(t), 11*C0 + sqrt(179)*C2*cos(sqrt(179)*t) + (-58*C1/3 - 77*C2/3)*sin(sqrt(179)*t)), \
Eq(z(t), 3*C0 + sqrt(179)*(-7*C1/3 - 11*C2/3)*cos(sqrt(179)*t) + (11*C1 - 7*C2)*sin(sqrt(179)*t))]
assert checksysodesol(eq2, sol2) == (True, [0, 0, 0])
eq3 = (Eq(3*diff(x(t),t),4*5*(y(t)-z(t))),Eq(4*diff(y(t),t),3*5*(z(t)-x(t))),Eq(5*diff(z(t),t),3*4*(x(t)-y(t))))
sol3 = [Eq(x(t), C0 + 5*sqrt(2)*C1*cos(5*sqrt(2)*t) + (12*C1/5 + 164*C2/15)*sin(5*sqrt(2)*t)), \
Eq(y(t), C0 + 5*sqrt(2)*C2*cos(5*sqrt(2)*t) + (-51*C1/10 - 12*C2/5)*sin(5*sqrt(2)*t)), \
Eq(z(t), C0 + 5*sqrt(2)*(-9*C1/25 - 16*C2/25)*cos(5*sqrt(2)*t) + (12*C1/5 - 12*C2/5)*sin(5*sqrt(2)*t))]
assert checksysodesol(eq3, sol3) == (True, [0, 0, 0])
f = t**3 + log(t)
g = t**2 + sin(t)
eq4 = (Eq(diff(x(t),t),(4*f+g)*x(t)-f*y(t)-2*f*z(t)), Eq(diff(y(t),t),2*f*x(t)+(f+g)*y(t)-2*f*z(t)), Eq(diff(z(t),t),5*f*x(t)+f*y(t)+(-3*f+g)*z(t)))
sol4 = [Eq(x(t), (C1*exp(-2*Integral(t**3 + log(t), t)) + C2*(sqrt(3)*sin(sqrt(3)*Integral(t**3 + log(t), t))/6 \
+ cos(sqrt(3)*Integral(t**3 + log(t), t))/2) + C3*(sin(sqrt(3)*Integral(t**3 + log(t), t))/2 - \
sqrt(3)*cos(sqrt(3)*Integral(t**3 + log(t), t))/6))*exp(Integral(-t**2 - sin(t), t))), Eq(y(t), \
(C2*(sqrt(3)*sin(sqrt(3)*Integral(t**3 + log(t), t))/6 + cos(sqrt(3)*Integral(t**3 + log(t), t))/2) + \
C3*(sin(sqrt(3)*Integral(t**3 + log(t), t))/2 - sqrt(3)*cos(sqrt(3)*Integral(t**3 + log(t), t))/6))*\
exp(Integral(-t**2 - sin(t), t))), Eq(z(t), (C1*exp(-2*Integral(t**3 + log(t), t)) + C2*cos(sqrt(3)*\
Integral(t**3 + log(t), t)) + C3*sin(sqrt(3)*Integral(t**3 + log(t), t)))*exp(Integral(-t**2 - sin(t), t)))]
assert dsolve(eq4) == sol4
eq5 = (Eq(diff(x(t),t),4*x(t) - z(t)),Eq(diff(y(t),t),2*x(t)+2*y(t)-z(t)),Eq(diff(z(t),t),3*x(t)+y(t)))
sol5 = [Eq(x(t), C1*exp(2*t) + C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t)/2 + C3*t*exp(2*t) + C3*exp(2*t)), \
Eq(y(t), C1*exp(2*t) + C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t)/2 + C3*t*exp(2*t)), \
Eq(z(t), 2*C1*exp(2*t) + 2*C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t) + C3*t*exp(2*t) + C3*exp(2*t))]
assert checksysodesol(eq5, sol5) == (True, [0, 0, 0])
eq6 = (Eq(diff(x(t),t),4*x(t) - y(t) - 2*z(t)),Eq(diff(y(t),t),2*x(t) + y(t)- 2*z(t)),Eq(diff(z(t),t),5*x(t)-3*z(t)))
sol6 = [Eq(x(t), C1*exp(2*t) + C2*(-sin(t)/5 + 3*cos(t)/5) + C3*(3*sin(t)/5 + cos(t)/5)),
Eq(y(t), C2*(-sin(t)/5 + 3*cos(t)/5) + C3*(3*sin(t)/5 + cos(t)/5)),
Eq(z(t), C1*exp(2*t) + C2*cos(t) + C3*sin(t))]
assert checksysodesol(eq5, sol5) == (True, [0, 0, 0])
def test_linear_3eq_order1_nonhomog():
e = [Eq(diff(f(x), x), -9*f(x) - 4*g(x)),
Eq(diff(g(x), x), -4*g(x)),
Eq(diff(h(x), x), h(x) + exp(x))]
raises(NotImplementedError, lambda: dsolve(e))
@XFAIL
def test_linear_3eq_order1_diagonal():
# code makes assumptions about coefficients being nonzero, breaks when assumptions are not true
e = [Eq(diff(f(x), x), f(x)),
Eq(diff(g(x), x), g(x)),
Eq(diff(h(x), x), h(x))]
s1 = [Eq(f(x), C1*exp(x)), Eq(g(x), C2*exp(x)), Eq(h(x), C3*exp(x))]
s = dsolve(e)
assert s == s1
def test_nonlinear_2eq_order1():
x, y, z = symbols('x, y, z', cls=Function)
t = Symbol('t')
eq1 = (Eq(diff(x(t),t),x(t)*y(t)**3), Eq(diff(y(t),t),y(t)**5))
sol1 = [
Eq(x(t), C1*exp((-1/(4*C2 + 4*t))**(-S(1)/4))),
Eq(y(t), -(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), C1*exp(-1/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), (-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), C1*exp(-I/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), -I*(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), C1*exp(I/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), I*(-1/(4*C2 + 4*t))**(S(1)/4))]
assert dsolve(eq1) == sol1
eq2 = (Eq(diff(x(t),t), exp(3*x(t))*y(t)**3),Eq(diff(y(t),t), y(t)**5))
sol2 = [
Eq(x(t), -log(C1 - 3/(-1/(4*C2 + 4*t))**(S(1)/4))/3),
Eq(y(t), -(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), -log(C1 + 3/(-1/(4*C2 + 4*t))**(S(1)/4))/3),
Eq(y(t), (-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), -log(C1 + 3*I/(-1/(4*C2 + 4*t))**(S(1)/4))/3),
Eq(y(t), -I*(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), -log(C1 - 3*I/(-1/(4*C2 + 4*t))**(S(1)/4))/3),
Eq(y(t), I*(-1/(4*C2 + 4*t))**(S(1)/4))]
assert dsolve(eq2) == sol2
eq3 = (Eq(diff(x(t),t), y(t)*x(t)), Eq(diff(y(t),t), x(t)**3))
tt = S(2)/3
sol3 = [
Eq(x(t), 6**tt/(6*(-sinh(sqrt(C1)*(C2 + t)/2)/sqrt(C1))**tt)),
Eq(y(t), sqrt(C1 + C1/sinh(sqrt(C1)*(C2 + t)/2)**2)/3)]
assert dsolve(eq3) == sol3
eq4 = (Eq(diff(x(t),t),x(t)*y(t)*sin(t)**2), Eq(diff(y(t),t),y(t)**2*sin(t)**2))
sol4 = set([Eq(x(t), -2*exp(C1)/(C2*exp(C1) + t - sin(2*t)/2)), Eq(y(t), -2/(C1 + t - sin(2*t)/2))])
assert dsolve(eq4) == sol4
eq5 = (Eq(x(t),t*diff(x(t),t)+diff(x(t),t)*diff(y(t),t)), Eq(y(t),t*diff(y(t),t)+diff(y(t),t)**2))
sol5 = set([Eq(x(t), C1*C2 + C1*t), Eq(y(t), C2**2 + C2*t)])
assert dsolve(eq5) == sol5
eq6 = (Eq(diff(x(t),t),x(t)**2*y(t)**3), Eq(diff(y(t),t),y(t)**5))
sol6 = [
Eq(x(t), 1/(C1 - 1/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), -(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), 1/(C1 + (-1/(4*C2 + 4*t))**(-S(1)/4))),
Eq(y(t), (-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), 1/(C1 + I/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), -I*(-1/(4*C2 + 4*t))**(S(1)/4)),
Eq(x(t), 1/(C1 - I/(-1/(4*C2 + 4*t))**(S(1)/4))),
Eq(y(t), I*(-1/(4*C2 + 4*t))**(S(1)/4))]
assert dsolve(eq6) == sol6
def test_checksysodesol():
x, y, z = symbols('x, y, z', cls=Function)
t = Symbol('t')
eq = (Eq(diff(x(t),t), 9*y(t)), Eq(diff(y(t),t), 12*x(t)))
sol = [Eq(x(t), 9*C1*exp(-6*sqrt(3)*t) + 9*C2*exp(6*sqrt(3)*t)), \
Eq(y(t), -6*sqrt(3)*C1*exp(-6*sqrt(3)*t) + 6*sqrt(3)*C2*exp(6*sqrt(3)*t))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), 2*x(t) + 4*y(t)), Eq(diff(y(t),t), 12*x(t) + 41*y(t)))
sol = [Eq(x(t), 4*C1*exp(t*(-sqrt(1713)/2 + S(43)/2)) + 4*C2*exp(t*(sqrt(1713)/2 + \
S(43)/2))), Eq(y(t), C1*(-sqrt(1713)/2 + S(39)/2)*exp(t*(-sqrt(1713)/2 + \
S(43)/2)) + C2*(S(39)/2 + sqrt(1713)/2)*exp(t*(sqrt(1713)/2 + S(43)/2)))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), x(t) + y(t)), Eq(diff(y(t),t), -2*x(t) + 2*y(t)))
sol = [Eq(x(t), (C1*sin(sqrt(7)*t/2) + C2*cos(sqrt(7)*t/2))*exp(3*t/2)), \
Eq(y(t), ((C1/2 - sqrt(7)*C2/2)*sin(sqrt(7)*t/2) + (sqrt(7)*C1/2 + \
C2/2)*cos(sqrt(7)*t/2))*exp(3*t/2))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), x(t) + y(t) + 9), Eq(diff(y(t),t), 2*x(t) + 5*y(t) + 23))
sol = [Eq(x(t), C1*exp(t*(-sqrt(6) + 3)) + C2*exp(t*(sqrt(6) + 3)) - \
S(22)/3), Eq(y(t), C1*(-sqrt(6) + 2)*exp(t*(-sqrt(6) + 3)) + C2*(2 + \
sqrt(6))*exp(t*(sqrt(6) + 3)) - S(5)/3)]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), x(t) + y(t) + 81), Eq(diff(y(t),t), -2*x(t) + y(t) + 23))
sol = [Eq(x(t), (C1*sin(sqrt(2)*t) + C2*cos(sqrt(2)*t))*exp(t) - S(58)/3), \
Eq(y(t), (sqrt(2)*C1*cos(sqrt(2)*t) - sqrt(2)*C2*sin(sqrt(2)*t))*exp(t) - S(185)/3)]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), 5*t*x(t) + 2*y(t)), Eq(diff(y(t),t), 2*x(t) + 5*t*y(t)))
sol = [Eq(x(t), (C1*exp((Integral(2, t).doit())) + C2*exp(-(Integral(2, t)).doit()))*\
exp((Integral(5*t, t)).doit())), Eq(y(t), (C1*exp((Integral(2, t)).doit()) - \
C2*exp(-(Integral(2, t)).doit()))*exp((Integral(5*t, t)).doit()))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), -t**2*x(t) + 5*t*y(t)))
sol = [Eq(x(t), (C1*cos((Integral(t**2, t)).doit()) + C2*sin((Integral(t**2, t)).doit()))*\
exp((Integral(5*t, t)).doit())), Eq(y(t), (-C1*sin((Integral(t**2, t)).doit()) + \
C2*cos((Integral(t**2, t)).doit()))*exp((Integral(5*t, t)).doit()))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), 5*t*x(t) + t**2*y(t)), Eq(diff(y(t),t), -t**2*x(t) + (5*t+9*t**2)*y(t)))
sol = [Eq(x(t), (C1*exp((-sqrt(77)/2 + S(9)/2)*(Integral(t**2, t)).doit()) + \
C2*exp((sqrt(77)/2 + S(9)/2)*(Integral(t**2, t)).doit()))*exp((Integral(5*t, t)).doit())), \
Eq(y(t), (C1*(-sqrt(77)/2 + S(9)/2)*exp((-sqrt(77)/2 + S(9)/2)*(Integral(t**2, t)).doit()) + \
C2*(sqrt(77)/2 + S(9)/2)*exp((sqrt(77)/2 + S(9)/2)*(Integral(t**2, t)).doit()))*exp((Integral(5*t, t)).doit()))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t,t), 5*x(t) + 43*y(t)), Eq(diff(y(t),t,t), x(t) + 9*y(t)))
root0 = -sqrt(-sqrt(47) + 7)
root1 = sqrt(-sqrt(47) + 7)
root2 = -sqrt(sqrt(47) + 7)
root3 = sqrt(sqrt(47) + 7)
sol = [Eq(x(t), 43*C1*exp(t*root0) + 43*C2*exp(t*root1) + 43*C3*exp(t*root2) + 43*C4*exp(t*root3)), \
Eq(y(t), C1*(root0**2 - 5)*exp(t*root0) + C2*(root1**2 - 5)*exp(t*root1) + \
C3*(root2**2 - 5)*exp(t*root2) + C4*(root3**2 - 5)*exp(t*root3))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t,t), 8*x(t)+3*y(t)+31), Eq(diff(y(t),t,t), 9*x(t)+7*y(t)+12))
root0 = -sqrt(-sqrt(109)/2 + S(15)/2)
root1 = sqrt(-sqrt(109)/2 + S(15)/2)
root2 = -sqrt(sqrt(109)/2 + S(15)/2)
root3 = sqrt(sqrt(109)/2 + S(15)/2)
sol = [Eq(x(t), 3*C1*exp(t*root0) + 3*C2*exp(t*root1) + 3*C3*exp(t*root2) + 3*C4*exp(t*root3) - S(181)/29), \
Eq(y(t), C1*(root0**2 - 8)*exp(t*root0) + C2*(root1**2 - 8)*exp(t*root1) + \
C3*(root2**2 - 8)*exp(t*root2) + C4*(root3**2 - 8)*exp(t*root3) + S(183)/29)]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t,t) - 9*diff(y(t),t) + 7*x(t),0), Eq(diff(y(t),t,t) + 9*diff(x(t),t) + 7*y(t),0))
sol = [Eq(x(t), C1*cos(t*(S(9)/2 + sqrt(109)/2)) + C2*sin(t*(S(9)/2 + sqrt(109)/2)) + \
C3*cos(t*(-sqrt(109)/2 + S(9)/2)) + C4*sin(t*(-sqrt(109)/2 + S(9)/2))), Eq(y(t), -C1*sin(t*(S(9)/2 + sqrt(109)/2)) \
+ C2*cos(t*(S(9)/2 + sqrt(109)/2)) - C3*sin(t*(-sqrt(109)/2 + S(9)/2)) + C4*cos(t*(-sqrt(109)/2 + S(9)/2)))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t,t), 9*t*diff(y(t),t)-9*y(t)), Eq(diff(y(t),t,t),7*t*diff(x(t),t)-7*x(t)))
I1 = sqrt(6)*7**(S(1)/4)*sqrt(pi)*erfi(sqrt(6)*7**(S(1)/4)*t/2)/2 - exp(3*sqrt(7)*t**2/2)/t
I2 = -sqrt(6)*7**(S(1)/4)*sqrt(pi)*erf(sqrt(6)*7**(S(1)/4)*t/2)/2 - exp(-3*sqrt(7)*t**2/2)/t
sol = [Eq(x(t), C3*t + t*(9*C1*I1 + 9*C2*I2)), Eq(y(t), C4*t + t*(3*sqrt(7)*C1*I1 - 3*sqrt(7)*C2*I2))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), 21*x(t)), Eq(diff(y(t),t), 17*x(t)+3*y(t)), Eq(diff(z(t),t), 5*x(t)+7*y(t)+9*z(t)))
sol = [Eq(x(t), C1*exp(21*t)), Eq(y(t), 17*C1*exp(21*t)/18 + C2*exp(3*t)), \
Eq(z(t), 209*C1*exp(21*t)/216 - 7*C2*exp(3*t)/6 + C3*exp(9*t))]
assert checksysodesol(eq, sol) == (True, [0, 0, 0])
eq = (Eq(diff(x(t),t),3*y(t)-11*z(t)),Eq(diff(y(t),t),7*z(t)-3*x(t)),Eq(diff(z(t),t),11*x(t)-7*y(t)))
sol = [Eq(x(t), 7*C0 + sqrt(179)*C1*cos(sqrt(179)*t) + (77*C1/3 + 130*C2/3)*sin(sqrt(179)*t)), \
Eq(y(t), 11*C0 + sqrt(179)*C2*cos(sqrt(179)*t) + (-58*C1/3 - 77*C2/3)*sin(sqrt(179)*t)), \
Eq(z(t), 3*C0 + sqrt(179)*(-7*C1/3 - 11*C2/3)*cos(sqrt(179)*t) + (11*C1 - 7*C2)*sin(sqrt(179)*t))]
assert checksysodesol(eq, sol) == (True, [0, 0, 0])
eq = (Eq(3*diff(x(t),t),4*5*(y(t)-z(t))),Eq(4*diff(y(t),t),3*5*(z(t)-x(t))),Eq(5*diff(z(t),t),3*4*(x(t)-y(t))))
sol = [Eq(x(t), C0 + 5*sqrt(2)*C1*cos(5*sqrt(2)*t) + (12*C1/5 + 164*C2/15)*sin(5*sqrt(2)*t)), \
Eq(y(t), C0 + 5*sqrt(2)*C2*cos(5*sqrt(2)*t) + (-51*C1/10 - 12*C2/5)*sin(5*sqrt(2)*t)), \
Eq(z(t), C0 + 5*sqrt(2)*(-9*C1/25 - 16*C2/25)*cos(5*sqrt(2)*t) + (12*C1/5 - 12*C2/5)*sin(5*sqrt(2)*t))]
assert checksysodesol(eq, sol) == (True, [0, 0, 0])
eq = (Eq(diff(x(t),t),4*x(t) - z(t)),Eq(diff(y(t),t),2*x(t)+2*y(t)-z(t)),Eq(diff(z(t),t),3*x(t)+y(t)))
sol = [Eq(x(t), C1*exp(2*t) + C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t)/2 + C3*t*exp(2*t) + C3*exp(2*t)), \
Eq(y(t), C1*exp(2*t) + C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t)/2 + C3*t*exp(2*t)), \
Eq(z(t), 2*C1*exp(2*t) + 2*C2*t*exp(2*t) + C2*exp(2*t) + C3*t**2*exp(2*t) + C3*t*exp(2*t) + C3*exp(2*t))]
assert checksysodesol(eq, sol) == (True, [0, 0, 0])
eq = (Eq(diff(x(t),t),4*x(t) - y(t) - 2*z(t)),Eq(diff(y(t),t),2*x(t) + y(t)- 2*z(t)),Eq(diff(z(t),t),5*x(t)-3*z(t)))
sol = [Eq(x(t), C1*exp(2*t) + C2*(-sin(t) + 3*cos(t)) + C3*(3*sin(t) + cos(t))), \
Eq(y(t), C2*(-sin(t) + 3*cos(t)) + C3*(3*sin(t) + cos(t))), Eq(z(t), C1*exp(2*t) + 5*C2*cos(t) + 5*C3*sin(t))]
assert checksysodesol(eq, sol) == (True, [0, 0, 0])
eq = (Eq(diff(x(t),t),x(t)*y(t)**3), Eq(diff(y(t),t),y(t)**5))
sol = [Eq(x(t), C1*exp((-1/(4*C2 + 4*t))**(-S(1)/4))), Eq(y(t), -(-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), C1*exp(-1/(-1/(4*C2 + 4*t))**(S(1)/4))), Eq(y(t), (-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), C1*exp(-I/(-1/(4*C2 + 4*t))**(S(1)/4))), Eq(y(t), -I*(-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), C1*exp(I/(-1/(4*C2 + 4*t))**(S(1)/4))), Eq(y(t), I*(-1/(4*C2 + 4*t))**(S(1)/4))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(diff(x(t),t), exp(3*x(t))*y(t)**3),Eq(diff(y(t),t), y(t)**5))
sol = [Eq(x(t), -log(C1 - 3/(-1/(4*C2 + 4*t))**(S(1)/4))/3), Eq(y(t), -(-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), -log(C1 + 3/(-1/(4*C2 + 4*t))**(S(1)/4))/3), Eq(y(t), (-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), -log(C1 + 3*I/(-1/(4*C2 + 4*t))**(S(1)/4))/3), Eq(y(t), -I*(-1/(4*C2 + 4*t))**(S(1)/4)), \
Eq(x(t), -log(C1 - 3*I/(-1/(4*C2 + 4*t))**(S(1)/4))/3), Eq(y(t), I*(-1/(4*C2 + 4*t))**(S(1)/4))]
assert checksysodesol(eq, sol) == (True, [0, 0])
eq = (Eq(x(t),t*diff(x(t),t)+diff(x(t),t)*diff(y(t),t)), Eq(y(t),t*diff(y(t),t)+diff(y(t),t)**2))
sol = set([Eq(x(t), C1*C2 + C1*t), Eq(y(t), C2**2 + C2*t)])
assert checksysodesol(eq, sol) == (True, [0, 0])
@slow
def test_nonlinear_3eq_order1():
x, y, z = symbols('x, y, z', cls=Function)
t, u = symbols('t u')
eq1 = (4*diff(x(t),t) + 2*y(t)*z(t), 3*diff(y(t),t) - z(t)*x(t), 5*diff(z(t),t) - x(t)*y(t))
sol1 = [Eq(4*Integral(1/(sqrt(-4*u**2 - 3*C1 + C2)*sqrt(-4*u**2 + 5*C1 - C2)), (u, x(t))),
C3 - sqrt(15)*t/15), Eq(3*Integral(1/(sqrt(-6*u**2 - C1 + 5*C2)*sqrt(3*u**2 + C1 - 4*C2)),
(u, y(t))), C3 + sqrt(5)*t/10), Eq(5*Integral(1/(sqrt(-10*u**2 - 3*C1 + C2)*
sqrt(5*u**2 + 4*C1 - C2)), (u, z(t))), C3 + sqrt(3)*t/6)]
assert [i.dummy_eq(j) for i, j in zip(dsolve(eq1), sol1)]
eq2 = (4*diff(x(t),t) + 2*y(t)*z(t)*sin(t), 3*diff(y(t),t) - z(t)*x(t)*sin(t), 5*diff(z(t),t) - x(t)*y(t)*sin(t))
sol2 = [Eq(3*Integral(1/(sqrt(-6*u**2 - C1 + 5*C2)*sqrt(3*u**2 + C1 - 4*C2)), (u, x(t))), C3 +
sqrt(5)*cos(t)/10), Eq(4*Integral(1/(sqrt(-4*u**2 - 3*C1 + C2)*sqrt(-4*u**2 + 5*C1 - C2)),
(u, y(t))), C3 - sqrt(15)*cos(t)/15), Eq(5*Integral(1/(sqrt(-10*u**2 - 3*C1 + C2)*
sqrt(5*u**2 + 4*C1 - C2)), (u, z(t))), C3 + sqrt(3)*cos(t)/6)]
assert [i.dummy_eq(j) for i, j in zip(dsolve(eq2), sol2)]
def test_checkodesol():
from sympy import Ei
# For the most part, checkodesol is well tested in the tests below.
# These tests only handle cases not checked below.
raises(ValueError, lambda: checkodesol(f(x, y).diff(x), Eq(f(x, y), x)))
raises(ValueError, lambda: checkodesol(f(x).diff(x), Eq(f(x, y),
x), f(x, y)))
assert checkodesol(f(x).diff(x), Eq(f(x, y), x)) == \
(False, -f(x).diff(x) + f(x, y).diff(x) - 1)
assert checkodesol(f(x).diff(x), Eq(f(x), x)) is not True
assert checkodesol(f(x).diff(x), Eq(f(x), x)) == (False, 1)
sol1 = Eq(f(x)**5 + 11*f(x) - 2*f(x) + x, 0)
assert checkodesol(diff(sol1.lhs, x), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x)*exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 2), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 2)*exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3)*exp(f(x)), sol1) == (True, 0)
assert checkodesol(diff(sol1.lhs, x, 3), Eq(f(x), x*log(x))) == \
(False, 60*x**4*((log(x) + 1)**2 + log(x))*(
log(x) + 1)*log(x)**2 - 5*x**4*log(x)**4 - 9)
assert checkodesol(diff(exp(f(x)) + x, x)*x, Eq(exp(f(x)) + x)) == \
(True, 0)
assert checkodesol(diff(exp(f(x)) + x, x)*x, Eq(exp(f(x)) + x),
solve_for_func=False) == (True, 0)
assert checkodesol(f(x).diff(x, 2), [Eq(f(x), C1 + C2*x),
Eq(f(x), C2 + C1*x), Eq(f(x), C1*x + C2*x**2)]) == \
[(True, 0), (True, 0), (False, C2)]
assert checkodesol(f(x).diff(x, 2), set([Eq(f(x), C1 + C2*x),
Eq(f(x), C2 + C1*x), Eq(f(x), C1*x + C2*x**2)])) == \
set([(True, 0), (True, 0), (False, C2)])
assert checkodesol(f(x).diff(x) - 1/f(x)/2, Eq(f(x)**2, x)) == \
[(True, 0), (True, 0)]
assert checkodesol(f(x).diff(x) - f(x), Eq(C1*exp(x), f(x))) == (True, 0)
# Based on test_1st_homogeneous_coeff_ode2_eq3sol. Make sure that
# checkodesol tries back substituting f(x) when it can.
eq3 = x*exp(f(x)/x) + f(x) - x*f(x).diff(x)
sol3 = Eq(f(x), log(log(C1/x)**(-x)))
assert not checkodesol(eq3, sol3)[1].has(f(x))
# This case was failing intermittently depending on hash-seed:
eqn = Eq(Derivative(x*Derivative(f(x), x), x)/x, exp(x))
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
@slow
def test_dsolve_options():
eq = x*f(x).diff(x) + f(x)
a = dsolve(eq, hint='all')
b = dsolve(eq, hint='all', simplify=False)
c = dsolve(eq, hint='all_Integral')
keys = ['1st_exact', '1st_exact_Integral', '1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_dep_div_indep',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral', '1st_linear',
'1st_linear_Integral', 'almost_linear', 'almost_linear_Integral',
'best', 'best_hint', 'default', 'lie_group',
'nth_linear_euler_eq_homogeneous', 'order',
'separable', 'separable_Integral']
Integral_keys = ['1st_exact_Integral',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral', '1st_linear_Integral',
'almost_linear_Integral', 'best', 'best_hint', 'default',
'nth_linear_euler_eq_homogeneous',
'order', 'separable_Integral']
assert sorted(a.keys()) == keys
assert a['order'] == ode_order(eq, f(x))
assert a['best'] == Eq(f(x), C1/x)
assert dsolve(eq, hint='best') == Eq(f(x), C1/x)
assert a['default'] == 'separable'
assert a['best_hint'] == 'separable'
assert not a['1st_exact'].has(Integral)
assert not a['separable'].has(Integral)
assert not a['1st_homogeneous_coeff_best'].has(Integral)
assert not a['1st_homogeneous_coeff_subs_dep_div_indep'].has(Integral)
assert not a['1st_homogeneous_coeff_subs_indep_div_dep'].has(Integral)
assert not a['1st_linear'].has(Integral)
assert a['1st_linear_Integral'].has(Integral)
assert a['1st_exact_Integral'].has(Integral)
assert a['1st_homogeneous_coeff_subs_dep_div_indep_Integral'].has(Integral)
assert a['1st_homogeneous_coeff_subs_indep_div_dep_Integral'].has(Integral)
assert a['separable_Integral'].has(Integral)
assert sorted(b.keys()) == keys
assert b['order'] == ode_order(eq, f(x))
assert b['best'] == Eq(f(x), C1/x)
assert dsolve(eq, hint='best', simplify=False) == Eq(f(x), C1/x)
assert b['default'] == 'separable'
assert b['best_hint'] == '1st_linear'
assert a['separable'] != b['separable']
assert a['1st_homogeneous_coeff_subs_dep_div_indep'] != \
b['1st_homogeneous_coeff_subs_dep_div_indep']
assert a['1st_homogeneous_coeff_subs_indep_div_dep'] != \
b['1st_homogeneous_coeff_subs_indep_div_dep']
assert not b['1st_exact'].has(Integral)
assert not b['separable'].has(Integral)
assert not b['1st_homogeneous_coeff_best'].has(Integral)
assert not b['1st_homogeneous_coeff_subs_dep_div_indep'].has(Integral)
assert not b['1st_homogeneous_coeff_subs_indep_div_dep'].has(Integral)
assert not b['1st_linear'].has(Integral)
assert b['1st_linear_Integral'].has(Integral)
assert b['1st_exact_Integral'].has(Integral)
assert b['1st_homogeneous_coeff_subs_dep_div_indep_Integral'].has(Integral)
assert b['1st_homogeneous_coeff_subs_indep_div_dep_Integral'].has(Integral)
assert b['separable_Integral'].has(Integral)
assert sorted(c.keys()) == Integral_keys
raises(ValueError, lambda: dsolve(eq, hint='notarealhint'))
raises(ValueError, lambda: dsolve(eq, hint='Liouville'))
assert dsolve(f(x).diff(x) - 1/f(x)**2, hint='all')['best'] == \
dsolve(f(x).diff(x) - 1/f(x)**2, hint='best')
assert dsolve(f(x) + f(x).diff(x) + sin(x).diff(x) + 1, f(x),
hint="1st_linear_Integral") == \
Eq(f(x), (C1 + Integral((-sin(x).diff(x) - 1)*
exp(Integral(1, x)), x))*exp(-Integral(1, x)))
def test_classify_ode():
assert classify_ode(f(x).diff(x, 2), f(x)) == \
('nth_algebraic',
'nth_linear_constant_coeff_homogeneous',
'nth_linear_euler_eq_homogeneous',
'Liouville',
'2nd_power_series_ordinary',
'nth_algebraic_Integral',
'Liouville_Integral',
)
assert classify_ode(f(x), f(x)) == ()
assert classify_ode(Eq(f(x).diff(x), 0), f(x)) == (
'nth_algebraic',
'separable',
'1st_linear', '1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_dep_div_indep',
'1st_power_series', 'lie_group',
'nth_linear_constant_coeff_homogeneous',
'nth_linear_euler_eq_homogeneous',
'nth_algebraic_Integral',
'separable_Integral',
'1st_linear_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral')
assert classify_ode(f(x).diff(x)**2, f(x)) == (
'nth_algebraic',
'lie_group',
'nth_algebraic_Integral')
# issue 4749: f(x) should be cleared from highest derivative before classifying
a = classify_ode(Eq(f(x).diff(x) + f(x), x), f(x))
b = classify_ode(f(x).diff(x)*f(x) + f(x)*f(x) - x*f(x), f(x))
c = classify_ode(f(x).diff(x)/f(x) + f(x)/f(x) - x/f(x), f(x))
assert a == ('1st_linear',
'Bernoulli',
'almost_linear',
'1st_power_series', "lie_group",
'nth_linear_constant_coeff_undetermined_coefficients',
'nth_linear_constant_coeff_variation_of_parameters',
'1st_linear_Integral',
'Bernoulli_Integral',
'almost_linear_Integral',
'nth_linear_constant_coeff_variation_of_parameters_Integral')
assert b == c != ()
assert classify_ode(
2*x*f(x)*f(x).diff(x) + (1 + x)*f(x)**2 - exp(x), f(x)
) == ('Bernoulli', 'almost_linear', 'lie_group',
'Bernoulli_Integral', 'almost_linear_Integral')
assert 'Riccati_special_minus2' in \
classify_ode(2*f(x).diff(x) + f(x)**2 - f(x)/x + 3*x**(-2), f(x))
raises(ValueError, lambda: classify_ode(x + f(x, y).diff(x).diff(
y), f(x, y)))
# issue 5176
k = Symbol('k')
assert classify_ode(f(x).diff(x)/(k*f(x) + k*x*f(x)) + 2*f(x)/(k*f(x) +
k*x*f(x)) + x*f(x).diff(x)/(k*f(x) + k*x*f(x)) + z, f(x)) == \
('separable', '1st_exact', '1st_power_series', 'lie_group',
'separable_Integral', '1st_exact_Integral')
# preprocessing
ans = ('nth_algebraic', 'separable', '1st_exact', '1st_linear', 'Bernoulli',
'1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_dep_div_indep',
'1st_power_series', 'lie_group',
'nth_linear_constant_coeff_undetermined_coefficients',
'nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients',
'nth_linear_constant_coeff_variation_of_parameters',
'nth_linear_euler_eq_nonhomogeneous_variation_of_parameters',
'nth_algebraic_Integral',
'separable_Integral', '1st_exact_Integral',
'1st_linear_Integral',
'Bernoulli_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral',
'nth_linear_constant_coeff_variation_of_parameters_Integral',
'nth_linear_euler_eq_nonhomogeneous_variation_of_parameters_Integral')
# w/o f(x) given
assert classify_ode(diff(f(x) + x, x) + diff(f(x), x)) == ans
# w/ f(x) and prep=True
assert classify_ode(diff(f(x) + x, x) + diff(f(x), x), f(x),
prep=True) == ans
assert classify_ode(Eq(2*x**3*f(x).diff(x), 0), f(x)) == \
('nth_algebraic', 'separable', '1st_linear', '1st_power_series',
'lie_group', 'nth_linear_euler_eq_homogeneous',
'nth_algebraic_Integral', 'separable_Integral',
'1st_linear_Integral')
assert classify_ode(Eq(2*f(x)**3*f(x).diff(x), 0), f(x)) == \
('nth_algebraic', 'separable', '1st_power_series', 'lie_group',
'nth_algebraic_Integral', 'separable_Integral')
# test issue 13864
assert classify_ode(Eq(diff(f(x), x) - f(x)**x, 0), f(x)) == \
('1st_power_series', 'lie_group')
assert isinstance(classify_ode(Eq(f(x), 5), f(x), dict=True), dict)
def test_classify_ode_ics():
# Dummy
eq = f(x).diff(x, x) - f(x)
# Not f(0) or f'(0)
ics = {x: 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
############################
# f(0) type (AppliedUndef) #
############################
# Wrong function
ics = {g(0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Contains x
ics = {f(x): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Too many args
ics = {f(0, 0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# point contains f
# XXX: Should be NotImplementedError
ics = {f(0): f(1)}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Does not raise
ics = {f(0): 1}
classify_ode(eq, f(x), ics=ics)
#####################
# f'(0) type (Subs) #
#####################
# Wrong function
ics = {g(x).diff(x).subs(x, 0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Contains x
ics = {f(y).diff(y).subs(y, x): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Wrong variable
ics = {f(y).diff(y).subs(y, 0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Too many args
ics = {f(x, y).diff(x).subs(x, 0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Derivative wrt wrong vars
ics = {Derivative(f(x), x, y).subs(x, 0): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# point contains f
# XXX: Should be NotImplementedError
ics = {f(x).diff(x).subs(x, 0): f(0)}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Does not raise
ics = {f(x).diff(x).subs(x, 0): 1}
classify_ode(eq, f(x), ics=ics)
###########################
# f'(y) type (Derivative) #
###########################
# Wrong function
ics = {g(x).diff(x).subs(x, y): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Contains x
ics = {f(y).diff(y).subs(y, x): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Too many args
ics = {f(x, y).diff(x).subs(x, y): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Derivative wrt wrong vars
ics = {Derivative(f(x), x, z).subs(x, y): 1}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# point contains f
# XXX: Should be NotImplementedError
ics = {f(x).diff(x).subs(x, y): f(0)}
raises(ValueError, lambda: classify_ode(eq, f(x), ics=ics))
# Does not raise
ics = {f(x).diff(x).subs(x, y): 1}
classify_ode(eq, f(x), ics=ics)
def test_classify_sysode():
# Here x is assumed to be x(t) and y as y(t) for simplicity.
# Similarly diff(x,t) and diff(y,y) is assumed to be x1 and y1 respectively.
k, l, m, n = symbols('k, l, m, n', Integer=True)
k1, k2, k3, l1, l2, l3, m1, m2, m3 = symbols('k1, k2, k3, l1, l2, l3, m1, m2, m3', Integer=True)
P, Q, R, p, q, r = symbols('P, Q, R, p, q, r', cls=Function)
P1, P2, P3, Q1, Q2, R1, R2 = symbols('P1, P2, P3, Q1, Q2, R1, R2', cls=Function)
x, y, z = symbols('x, y, z', cls=Function)
t = symbols('t')
x1 = diff(x(t),t) ; y1 = diff(y(t),t) ; z1 = diff(z(t),t)
x2 = diff(x(t),t,t) ; y2 = diff(y(t),t,t) ; z2 = diff(z(t),t,t)
eq1 = (Eq(diff(x(t),t), 5*t*x(t) + 2*y(t)), Eq(diff(y(t),t), 2*x(t) + 5*t*y(t)))
sol1 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): -5*t, (1, x(t), 1): 0, (0, x(t), 1): 1, \
(1, y(t), 0): -5*t, (1, x(t), 0): -2, (0, y(t), 1): 0, (0, y(t), 0): -2, (1, y(t), 1): 1}, \
'type_of_equation': 'type3', 'func': [x(t), y(t)], 'is_linear': True, 'eq': [-5*t*x(t) - 2*y(t) + \
Derivative(x(t), t), -5*t*y(t) - 2*x(t) + Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq1) == sol1
eq2 = (Eq(x2, k*x(t) - l*y1), Eq(y2, l*x1 + k*y(t)))
sol2 = {'order': {y(t): 2, x(t): 2}, 'type_of_equation': 'type3', 'is_linear': True, 'eq': \
[-k*x(t) + l*Derivative(y(t), t) + Derivative(x(t), t, t), -k*y(t) - l*Derivative(x(t), t) + \
Derivative(y(t), t, t)], 'no_of_equation': 2, 'func_coeff': {(0, y(t), 0): 0, (0, x(t), 2): 1, \
(1, y(t), 1): 0, (1, y(t), 2): 1, (1, x(t), 2): 0, (0, y(t), 2): 0, (0, x(t), 0): -k, (1, x(t), 1): \
-l, (0, x(t), 1): 0, (0, y(t), 1): l, (1, x(t), 0): 0, (1, y(t), 0): -k}, 'func': [x(t), y(t)]}
assert classify_sysode(eq2) == sol2
eq3 = (Eq(x2+4*x1+3*y1+9*x(t)+7*y(t), 11*exp(I*t)), Eq(y2+5*x1+8*y1+3*x(t)+12*y(t), 2*exp(I*t)))
sol3 = {'no_of_equation': 2, 'func_coeff': {(1, x(t), 2): 0, (0, y(t), 2): 0, (0, x(t), 0): 9, \
(1, x(t), 1): 5, (0, x(t), 1): 4, (0, y(t), 1): 3, (1, x(t), 0): 3, (1, y(t), 0): 12, (0, y(t), 0): 7, \
(0, x(t), 2): 1, (1, y(t), 2): 1, (1, y(t), 1): 8}, 'type_of_equation': 'type4', 'func': [x(t), y(t)], \
'is_linear': True, 'eq': [9*x(t) + 7*y(t) - 11*exp(I*t) + 4*Derivative(x(t), t) + 3*Derivative(y(t), t) + \
Derivative(x(t), t, t), 3*x(t) + 12*y(t) - 2*exp(I*t) + 5*Derivative(x(t), t) + 8*Derivative(y(t), t) + \
Derivative(y(t), t, t)], 'order': {y(t): 2, x(t): 2}}
assert classify_sysode(eq3) == sol3
eq4 = (Eq((4*t**2 + 7*t + 1)**2*x2, 5*x(t) + 35*y(t)), Eq((4*t**2 + 7*t + 1)**2*y2, x(t) + 9*y(t)))
sol4 = {'no_of_equation': 2, 'func_coeff': {(1, x(t), 2): 0, (0, y(t), 2): 0, (0, x(t), 0): -5, \
(1, x(t), 1): 0, (0, x(t), 1): 0, (0, y(t), 1): 0, (1, x(t), 0): -1, (1, y(t), 0): -9, (0, y(t), 0): -35, \
(0, x(t), 2): 16*t**4 + 56*t**3 + 57*t**2 + 14*t + 1, (1, y(t), 2): 16*t**4 + 56*t**3 + 57*t**2 + 14*t + 1, \
(1, y(t), 1): 0}, 'type_of_equation': 'type10', 'func': [x(t), y(t)], 'is_linear': True, \
'eq': [(4*t**2 + 7*t + 1)**2*Derivative(x(t), t, t) - 5*x(t) - 35*y(t), (4*t**2 + 7*t + 1)**2*Derivative(y(t), t, t)\
- x(t) - 9*y(t)], 'order': {y(t): 2, x(t): 2}}
assert classify_sysode(eq4) == sol4
eq5 = (Eq(diff(x(t),t), x(t) + y(t) + 9), Eq(diff(y(t),t), 2*x(t) + 5*y(t) + 23))
sol5 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): -1, (1, x(t), 1): 0, (0, x(t), 1): 1, (1, y(t), 0): -5, \
(1, x(t), 0): -2, (0, y(t), 1): 0, (0, y(t), 0): -1, (1, y(t), 1): 1}, 'type_of_equation': 'type2', \
'func': [x(t), y(t)], 'is_linear': True, 'eq': [-x(t) - y(t) + Derivative(x(t), t) - 9, -2*x(t) - 5*y(t) + \
Derivative(y(t), t) - 23], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq5) == sol5
eq6 = (Eq(x1, exp(k*x(t))*P(x(t),y(t))), Eq(y1,r(y(t))*P(x(t),y(t))))
sol6 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): 0, (1, x(t), 1): 0, (0, x(t), 1): 1, (1, y(t), 0): 0, \
(1, x(t), 0): 0, (0, y(t), 1): 0, (0, y(t), 0): 0, (1, y(t), 1): 1}, 'type_of_equation': 'type2', 'func': \
[x(t), y(t)], 'is_linear': False, 'eq': [-P(x(t), y(t))*exp(k*x(t)) + Derivative(x(t), t), -P(x(t), \
y(t))*r(y(t)) + Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq6) == sol6
eq7 = (Eq(x1, x(t)**2+y(t)/x(t)), Eq(y1, x(t)/y(t)))
sol7 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): 0, (1, x(t), 1): 0, (0, x(t), 1): 1, (1, y(t), 0): 0, \
(1, x(t), 0): -1/y(t), (0, y(t), 1): 0, (0, y(t), 0): -1/x(t), (1, y(t), 1): 1}, 'type_of_equation': 'type3', \
'func': [x(t), y(t)], 'is_linear': False, 'eq': [-x(t)**2 + Derivative(x(t), t) - y(t)/x(t), -x(t)/y(t) + \
Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq7) == sol7
eq8 = (Eq(x1, P1(x(t))*Q1(y(t))*R(x(t),y(t),t)), Eq(y1, P1(x(t))*Q1(y(t))*R(x(t),y(t),t)))
sol8 = {'func': [x(t), y(t)], 'is_linear': False, 'type_of_equation': 'type4', 'eq': \
[-P1(x(t))*Q1(y(t))*R(x(t), y(t), t) + Derivative(x(t), t), -P1(x(t))*Q1(y(t))*R(x(t), y(t), t) + \
Derivative(y(t), t)], 'func_coeff': {(0, y(t), 1): 0, (1, y(t), 1): 1, (1, x(t), 1): 0, (0, y(t), 0): 0, \
(1, x(t), 0): 0, (0, x(t), 0): 0, (1, y(t), 0): 0, (0, x(t), 1): 1}, 'order': {y(t): 1, x(t): 1}, 'no_of_equation': 2}
assert classify_sysode(eq8) == sol8
eq9 = (Eq(x1,3*y(t)-11*z(t)),Eq(y1,7*z(t)-3*x(t)),Eq(z1,11*x(t)-7*y(t)))
sol9 = {'no_of_equation': 3, 'func_coeff': {(1, y(t), 0): 0, (2, y(t), 1): 0, (2, z(t), 1): 1, \
(0, x(t), 0): 0, (2, x(t), 1): 0, (1, x(t), 1): 0, (2, y(t), 0): 7, (0, x(t), 1): 1, (1, z(t), 1): 0, \
(0, y(t), 1): 0, (1, x(t), 0): 3, (0, z(t), 0): 11, (0, y(t), 0): -3, (1, z(t), 0): -7, (0, z(t), 1): 0, \
(2, x(t), 0): -11, (2, z(t), 0): 0, (1, y(t), 1): 1}, 'type_of_equation': 'type2', 'func': [x(t), y(t), z(t)], \
'is_linear': True, 'eq': [-3*y(t) + 11*z(t) + Derivative(x(t), t), 3*x(t) - 7*z(t) + Derivative(y(t), t), \
-11*x(t) + 7*y(t) + Derivative(z(t), t)], 'order': {z(t): 1, y(t): 1, x(t): 1}}
assert classify_sysode(eq9) == sol9
eq10 = (x2 + log(t)*(t*x1 - x(t)) + exp(t)*(t*y1 - y(t)), y2 + (t**2)*(t*x1 - x(t)) + (t)*(t*y1 - y(t)))
sol10 = {'no_of_equation': 2, 'func_coeff': {(1, x(t), 2): 0, (0, y(t), 2): 0, (0, x(t), 0): -log(t), \
(1, x(t), 1): t**3, (0, x(t), 1): t*log(t), (0, y(t), 1): t*exp(t), (1, x(t), 0): -t**2, (1, y(t), 0): -t, \
(0, y(t), 0): -exp(t), (0, x(t), 2): 1, (1, y(t), 2): 1, (1, y(t), 1): t**2}, 'type_of_equation': 'type11', \
'func': [x(t), y(t)], 'is_linear': True, 'eq': [(t*Derivative(x(t), t) - x(t))*log(t) + (t*Derivative(y(t), t) - \
y(t))*exp(t) + Derivative(x(t), t, t), t**2*(t*Derivative(x(t), t) - x(t)) + t*(t*Derivative(y(t), t) - y(t)) \
+ Derivative(y(t), t, t)], 'order': {y(t): 2, x(t): 2}}
assert classify_sysode(eq10) == sol10
eq11 = (Eq(x1,x(t)*y(t)**3), Eq(y1,y(t)**5))
sol11 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): -y(t)**3, (1, x(t), 1): 0, (0, x(t), 1): 1, \
(1, y(t), 0): 0, (1, x(t), 0): 0, (0, y(t), 1): 0, (0, y(t), 0): 0, (1, y(t), 1): 1}, 'type_of_equation': \
'type1', 'func': [x(t), y(t)], 'is_linear': False, 'eq': [-x(t)*y(t)**3 + Derivative(x(t), t), \
-y(t)**5 + Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq11) == sol11
eq12 = (Eq(x1, y(t)), Eq(y1, x(t)))
sol12 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): 0, (1, x(t), 1): 0, (0, x(t), 1): 1, (1, y(t), 0): 0, \
(1, x(t), 0): -1, (0, y(t), 1): 0, (0, y(t), 0): -1, (1, y(t), 1): 1}, 'type_of_equation': 'type1', 'func': \
[x(t), y(t)], 'is_linear': True, 'eq': [-y(t) + Derivative(x(t), t), -x(t) + Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq12) == sol12
eq13 = (Eq(x1,x(t)*y(t)*sin(t)**2), Eq(y1,y(t)**2*sin(t)**2))
sol13 = {'no_of_equation': 2, 'func_coeff': {(0, x(t), 0): -y(t)*sin(t)**2, (1, x(t), 1): 0, (0, x(t), 1): 1, \
(1, y(t), 0): 0, (1, x(t), 0): 0, (0, y(t), 1): 0, (0, y(t), 0): -x(t)*sin(t)**2, (1, y(t), 1): 1}, \
'type_of_equation': 'type4', 'func': [x(t), y(t)], 'is_linear': False, 'eq': [-x(t)*y(t)*sin(t)**2 + \
Derivative(x(t), t), -y(t)**2*sin(t)**2 + Derivative(y(t), t)], 'order': {y(t): 1, x(t): 1}}
assert classify_sysode(eq13) == sol13
eq14 = (Eq(x1, 21*x(t)), Eq(y1, 17*x(t)+3*y(t)), Eq(z1, 5*x(t)+7*y(t)+9*z(t)))
sol14 = {'no_of_equation': 3, 'func_coeff': {(1, y(t), 0): -3, (2, y(t), 1): 0, (2, z(t), 1): 1, \
(0, x(t), 0): -21, (2, x(t), 1): 0, (1, x(t), 1): 0, (2, y(t), 0): -7, (0, x(t), 1): 1, (1, z(t), 1): 0, \
(0, y(t), 1): 0, (1, x(t), 0): -17, (0, z(t), 0): 0, (0, y(t), 0): 0, (1, z(t), 0): 0, (0, z(t), 1): 0, \
(2, x(t), 0): -5, (2, z(t), 0): -9, (1, y(t), 1): 1}, 'type_of_equation': 'type1', 'func': [x(t), y(t), z(t)], \
'is_linear': True, 'eq': [-21*x(t) + Derivative(x(t), t), -17*x(t) - 3*y(t) + Derivative(y(t), t), -5*x(t) - \
7*y(t) - 9*z(t) + Derivative(z(t), t)], 'order': {z(t): 1, y(t): 1, x(t): 1}}
assert classify_sysode(eq14) == sol14
eq15 = (Eq(x1,4*x(t)+5*y(t)+2*z(t)),Eq(y1,x(t)+13*y(t)+9*z(t)),Eq(z1,32*x(t)+41*y(t)+11*z(t)))
sol15 = {'no_of_equation': 3, 'func_coeff': {(1, y(t), 0): -13, (2, y(t), 1): 0, (2, z(t), 1): 1, \
(0, x(t), 0): -4, (2, x(t), 1): 0, (1, x(t), 1): 0, (2, y(t), 0): -41, (0, x(t), 1): 1, (1, z(t), 1): 0, \
(0, y(t), 1): 0, (1, x(t), 0): -1, (0, z(t), 0): -2, (0, y(t), 0): -5, (1, z(t), 0): -9, (0, z(t), 1): 0, \
(2, x(t), 0): -32, (2, z(t), 0): -11, (1, y(t), 1): 1}, 'type_of_equation': 'type6', 'func': \
[x(t), y(t), z(t)], 'is_linear': True, 'eq': [-4*x(t) - 5*y(t) - 2*z(t) + Derivative(x(t), t), -x(t) - 13*y(t) - \
9*z(t) + Derivative(y(t), t), -32*x(t) - 41*y(t) - 11*z(t) + Derivative(z(t), t)], 'order': {z(t): 1, y(t): 1, x(t): 1}}
assert classify_sysode(eq15) == sol15
eq16 = (Eq(3*x1,4*5*(y(t)-z(t))),Eq(4*y1,3*5*(z(t)-x(t))),Eq(5*z1,3*4*(x(t)-y(t))))
sol16 = {'no_of_equation': 3, 'func_coeff': {(1, y(t), 0): 0, (2, y(t), 1): 0, (2, z(t), 1): 5, \
(0, x(t), 0): 0, (2, x(t), 1): 0, (1, x(t), 1): 0, (2, y(t), 0): 12, (0, x(t), 1): 3, (1, z(t), 1): 0, \
(0, y(t), 1): 0, (1, x(t), 0): 15, (0, z(t), 0): 20, (0, y(t), 0): -20, (1, z(t), 0): -15, (0, z(t), 1): 0, \
(2, x(t), 0): -12, (2, z(t), 0): 0, (1, y(t), 1): 4}, 'type_of_equation': 'type3', 'func': [x(t), y(t), z(t)], \
'is_linear': True, 'eq': [-20*y(t) + 20*z(t) + 3*Derivative(x(t), t), 15*x(t) - 15*z(t) + 4*Derivative(y(t), t), \
-12*x(t) + 12*y(t) + 5*Derivative(z(t), t)], 'order': {z(t): 1, y(t): 1, x(t): 1}}
assert classify_sysode(eq16) == sol16
# issue 8193: funcs parameter for classify_sysode has to actually work
assert classify_sysode(eq1, funcs=[x(t), y(t)]) == sol1
def test_solve_ics():
# Basic tests that things work from dsolve.
assert dsolve(f(x).diff(x) - f(x), f(x), ics={f(0): 1}) == Eq(f(x), exp(x))
assert dsolve(f(x).diff(x) - f(x), f(x), ics={f(x).diff(x).subs(x, 0): 1}) == Eq(f(x), exp(x))
assert dsolve(f(x).diff(x, x) + f(x), f(x), ics={f(0): 1,
f(x).diff(x).subs(x, 0): 1}) == Eq(f(x), sin(x) + cos(x))
assert dsolve([f(x).diff(x) - f(x) + g(x), g(x).diff(x) - g(x) - f(x)],
[f(x), g(x)], ics={f(0): 1, g(0): 0}) == [Eq(f(x), exp(x)*cos(x)),
Eq(g(x), exp(x)*sin(x))]
# Test cases where dsolve returns two solutions.
eq = (x**2*f(x)**2 - x).diff(x)
assert dsolve(eq, f(x), ics={f(1): 0}) == [Eq(f(x),
-sqrt(x - 1)/x), Eq(f(x), sqrt(x - 1)/x)]
assert dsolve(eq, f(x), ics={f(x).diff(x).subs(x, 1): 0}) == [Eq(f(x),
-sqrt(x - S(1)/2)/x), Eq(f(x), sqrt(x - S(1)/2)/x)]
eq = cos(f(x)) - (x*sin(f(x)) - f(x)**2)*f(x).diff(x)
assert dsolve(eq, f(x),
ics={f(0):1}, hint='1st_exact', simplify=False) == Eq(x*cos(f(x)) + f(x)**3/3, S(1)/3)
assert dsolve(eq, f(x),
ics={f(0):1}, hint='1st_exact', simplify=True) == Eq(x*cos(f(x)) + f(x)**3/3, S(1)/3)
assert solve_ics([Eq(f(x), C1*exp(x))], [f(x)], [C1], {f(0): 1}) == {C1: 1}
assert solve_ics([Eq(f(x), C1*sin(x) + C2*cos(x))], [f(x)], [C1, C2],
{f(0): 1, f(pi/2): 1}) == {C1: 1, C2: 1}
assert solve_ics([Eq(f(x), C1*sin(x) + C2*cos(x))], [f(x)], [C1, C2],
{f(0): 1, f(x).diff(x).subs(x, 0): 1}) == {C1: 1, C2: 1}
# XXX: Ought to be ValueError
raises(NotImplementedError, lambda: solve_ics([Eq(f(x), C1*sin(x) + C2*cos(x))], [f(x)], [C1, C2], {f(0): 1, f(pi): 1}))
# XXX: Ought to be ValueError
raises(ValueError, lambda: solve_ics([Eq(f(x), C1*sin(x) + C2*cos(x))], [f(x)], [C1, C2], {f(0): 1}))
# Degenerate case. f'(0) is identically 0.
raises(ValueError, lambda: solve_ics([Eq(f(x), sqrt(C1 - x**2))], [f(x)], [C1], {f(x).diff(x).subs(x, 0): 0}))
EI, q, L = symbols('EI q L')
# eq = Eq(EI*diff(f(x), x, 4), q)
sols = [Eq(f(x), C1 + C2*x + C3*x**2 + C4*x**3 + q*x**4/(24*EI))]
funcs = [f(x)]
constants = [C1, C2, C3, C4]
# Test both cases, Derivative (the default from f(x).diff(x).subs(x, L)),
# and Subs
ics1 = {f(0): 0,
f(x).diff(x).subs(x, 0): 0,
f(L).diff(L, 2): 0,
f(L).diff(L, 3): 0}
ics2 = {f(0): 0,
f(x).diff(x).subs(x, 0): 0,
Subs(f(x).diff(x, 2), x, L): 0,
Subs(f(x).diff(x, 3), x, L): 0}
solved_constants1 = solve_ics(sols, funcs, constants, ics1)
solved_constants2 = solve_ics(sols, funcs, constants, ics2)
assert solved_constants1 == solved_constants2 == {
C1: 0,
C2: 0,
C3: L**2*q/(4*EI),
C4: -L*q/(6*EI)}
def test_ode_order():
f = Function('f')
g = Function('g')
x = Symbol('x')
assert ode_order(3*x*exp(f(x)), f(x)) == 0
assert ode_order(x*diff(f(x), x) + 3*x*f(x) - sin(x)/x, f(x)) == 1
assert ode_order(x**2*f(x).diff(x, x) + x*diff(f(x), x) - f(x), f(x)) == 2
assert ode_order(diff(x*exp(f(x)), x, x), f(x)) == 2
assert ode_order(diff(x*diff(x*exp(f(x)), x, x), x), f(x)) == 3
assert ode_order(diff(f(x), x, x), g(x)) == 0
assert ode_order(diff(f(x), x, x)*diff(g(x), x), f(x)) == 2
assert ode_order(diff(f(x), x, x)*diff(g(x), x), g(x)) == 1
assert ode_order(diff(x*diff(x*exp(f(x)), x, x), x), g(x)) == 0
# issue 5835: ode_order has to also work for unevaluated derivatives
# (ie, without using doit()).
assert ode_order(Derivative(x*f(x), x), f(x)) == 1
assert ode_order(x*sin(Derivative(x*f(x)**2, x, x)), f(x)) == 2
assert ode_order(Derivative(x*Derivative(x*exp(f(x)), x, x), x), g(x)) == 0
assert ode_order(Derivative(f(x), x, x), g(x)) == 0
assert ode_order(Derivative(x*exp(f(x)), x, x), f(x)) == 2
assert ode_order(Derivative(f(x), x, x)*Derivative(g(x), x), g(x)) == 1
assert ode_order(Derivative(x*Derivative(f(x), x, x), x), f(x)) == 3
assert ode_order(
x*sin(Derivative(x*Derivative(f(x), x)**2, x, x)), f(x)) == 3
# In all tests below, checkodesol has the order option set to prevent
# superfluous calls to ode_order(), and the solve_for_func flag set to False
# because dsolve() already tries to solve for the function, unless the
# simplify=False option is set.
def test_old_ode_tests():
# These are simple tests from the old ode module
eq1 = Eq(f(x).diff(x), 0)
eq2 = Eq(3*f(x).diff(x) - 5, 0)
eq3 = Eq(3*f(x).diff(x), 5)
eq4 = Eq(9*f(x).diff(x, x) + f(x), 0)
eq5 = Eq(9*f(x).diff(x, x), f(x))
# Type: a(x)f'(x)+b(x)*f(x)+c(x)=0
eq6 = Eq(x**2*f(x).diff(x) + 3*x*f(x) - sin(x)/x, 0)
eq7 = Eq(f(x).diff(x, x) - 3*diff(f(x), x) + 2*f(x), 0)
# Type: 2nd order, constant coefficients (two real different roots)
eq8 = Eq(f(x).diff(x, x) - 4*diff(f(x), x) + 4*f(x), 0)
# Type: 2nd order, constant coefficients (two real equal roots)
eq9 = Eq(f(x).diff(x, x) + 2*diff(f(x), x) + 3*f(x), 0)
# Type: 2nd order, constant coefficients (two complex roots)
eq10 = Eq(3*f(x).diff(x) - 1, 0)
eq11 = Eq(x*f(x).diff(x) - 1, 0)
sol1 = Eq(f(x), C1)
sol2 = Eq(f(x), C1 + 5*x/3)
sol3 = Eq(f(x), C1 + 5*x/3)
sol4 = Eq(f(x), C1*sin(x/3) + C2*cos(x/3))
sol5 = Eq(f(x), C1*exp(-x/3) + C2*exp(x/3))
sol6 = Eq(f(x), (C1 - cos(x))/x**3)
sol7 = Eq(f(x), (C1 + C2*exp(x))*exp(x))
sol8 = Eq(f(x), (C1 + C2*x)*exp(2*x))
sol9 = Eq(f(x), (C1*sin(x*sqrt(2)) + C2*cos(x*sqrt(2)))*exp(-x))
sol10 = Eq(f(x), C1 + x/3)
sol11 = Eq(f(x), C1 + log(x))
assert dsolve(eq1) == sol1
assert dsolve(eq1.lhs) == sol1
assert dsolve(eq2) == sol2
assert dsolve(eq3) == sol3
assert dsolve(eq4) == sol4
assert dsolve(eq5) == sol5
assert dsolve(eq6) == sol6
assert dsolve(eq7) == sol7
assert dsolve(eq8) == sol8
assert dsolve(eq9) == sol9
assert dsolve(eq10) == sol10
assert dsolve(eq11) == sol11
assert checkodesol(eq1, sol1, order=1, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=1, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=2, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=2, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=1, solve_for_func=False)[0]
assert checkodesol(eq7, sol7, order=2, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=2, solve_for_func=False)[0]
assert checkodesol(eq9, sol9, order=2, solve_for_func=False)[0]
assert checkodesol(eq10, sol10, order=1, solve_for_func=False)[0]
assert checkodesol(eq11, sol11, order=1, solve_for_func=False)[0]
@slow
def test_1st_linear():
# Type: first order linear form f'(x)+p(x)f(x)=q(x)
eq = Eq(f(x).diff(x) + x*f(x), x**2)
sol = Eq(f(x), (C1 + x*exp(x**2/2)
- sqrt(2)*sqrt(pi)*erfi(sqrt(2)*x/2)/2)*exp(-x**2/2))
assert dsolve(eq, hint='1st_linear') == sol
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_Bernoulli():
# Type: Bernoulli, f'(x) + p(x)*f(x) == q(x)*f(x)**n
eq = Eq(x*f(x).diff(x) + f(x) - f(x)**2, 0)
sol = dsolve(eq, f(x), hint='Bernoulli')
assert sol == Eq(f(x), 1/(x*(C1 + 1/x)))
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_Riccati_special_minus2():
# Type: Riccati special alpha = -2, a*dy/dx + b*y**2 + c*y/x +d/x**2
eq = 2*f(x).diff(x) + f(x)**2 - f(x)/x + 3*x**(-2)
sol = dsolve(eq, f(x), hint='Riccati_special_minus2')
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_1st_exact1():
# Type: Exact differential equation, p(x,f) + q(x,f)*f' == 0,
# where dp/df == dq/dx
eq1 = sin(x)*cos(f(x)) + cos(x)*sin(f(x))*f(x).diff(x)
eq2 = (2*x*f(x) + 1)/f(x) + (f(x) - x)/f(x)**2*f(x).diff(x)
eq3 = 2*x + f(x)*cos(x) + (2*f(x) + sin(x) - sin(f(x)))*f(x).diff(x)
eq4 = cos(f(x)) - (x*sin(f(x)) - f(x)**2)*f(x).diff(x)
eq5 = 2*x*f(x) + (x**2 + f(x)**2)*f(x).diff(x)
sol1 = [Eq(f(x), -acos(C1/cos(x)) + 2*pi), Eq(f(x), acos(C1/cos(x)))]
sol2 = Eq(f(x), exp(C1 - x**2 + LambertW(-x*exp(-C1 + x**2))))
sol2b = Eq(log(f(x)) + x/f(x) + x**2, C1)
sol3 = Eq(f(x)*sin(x) + cos(f(x)) + x**2 + f(x)**2, C1)
sol4 = Eq(x*cos(f(x)) + f(x)**3/3, C1)
sol5 = Eq(x**2*f(x) + f(x)**3/3, C1)
assert dsolve(eq1, f(x), hint='1st_exact') == sol1
assert dsolve(eq2, f(x), hint='1st_exact') == sol2
assert dsolve(eq3, f(x), hint='1st_exact') == sol3
assert dsolve(eq4, hint='1st_exact') == sol4
assert dsolve(eq5, hint='1st_exact', simplify=False) == sol5
assert checkodesol(eq1, sol1, order=1, solve_for_func=False)[0]
# issue 5080 blocks the testing of this solution
#assert checkodesol(eq2, sol2, order=1, solve_for_func=False)[0]
assert checkodesol(eq2, sol2b, order=1, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=1, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=1, solve_for_func=False)[0]
@slow
@XFAIL
def test_1st_exact2():
"""
This is an exact equation that fails under the exact engine. It is caught
by first order homogeneous albeit with a much contorted solution. The
exact engine fails because of a poorly simplified integral of q(0,y)dy,
where q is the function multiplying f'. The solutions should be
Eq(sqrt(x**2+f(x)**2)**3+y**3, C1). The equation below is
equivalent, but it is so complex that checkodesol fails, and takes a long
time to do so.
"""
if ON_TRAVIS:
skip("Too slow for travis.")
eq = (x*sqrt(x**2 + f(x)**2) - (x**2*f(x)/(f(x) -
sqrt(x**2 + f(x)**2)))*f(x).diff(x))
sol = dsolve(eq)
assert sol == Eq(log(x),
C1 - 9*sqrt(1 + f(x)**2/x**2)*asinh(f(x)/x)/(-27*f(x)/x +
27*sqrt(1 + f(x)**2/x**2)) - 9*sqrt(1 + f(x)**2/x**2)*
log(1 - sqrt(1 + f(x)**2/x**2)*f(x)/x + 2*f(x)**2/x**2)/
(-27*f(x)/x + 27*sqrt(1 + f(x)**2/x**2)) +
9*asinh(f(x)/x)*f(x)/(x*(-27*f(x)/x + 27*sqrt(1 + f(x)**2/x**2))) +
9*f(x)*log(1 - sqrt(1 + f(x)**2/x**2)*f(x)/x + 2*f(x)**2/x**2)/
(x*(-27*f(x)/x + 27*sqrt(1 + f(x)**2/x**2))))
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_separable1():
# test_separable1-5 are from Ordinary Differential Equations, Tenenbaum and
# Pollard, pg. 55
eq1 = f(x).diff(x) - f(x)
eq2 = x*f(x).diff(x) - f(x)
eq3 = f(x).diff(x) + sin(x)
eq4 = f(x)**2 + 1 - (x**2 + 1)*f(x).diff(x)
eq5 = f(x).diff(x)/tan(x) - f(x) - 2
eq6 = f(x).diff(x) * (1 - sin(f(x))) - 1
sol1 = Eq(f(x), C1*exp(x))
sol2 = Eq(f(x), C1*x)
sol3 = Eq(f(x), C1 + cos(x))
sol4 = Eq(atan(f(x)), C1 + atan(x))
sol5 = Eq(f(x), C1/cos(x) - 2)
sol6 = Eq(-x + f(x) + cos(f(x)), C1)
assert dsolve(eq1, hint='separable') == sol1
assert dsolve(eq2, hint='separable') == sol2
assert dsolve(eq3, hint='separable') == sol3
assert dsolve(eq4, hint='separable', simplify=False) == sol4
assert dsolve(eq5, hint='separable') == sol5
assert dsolve(eq6, hint='separable') == sol6
assert checkodesol(eq1, sol1, order=1, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=1, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=1, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=1, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=1, solve_for_func=False)[0]
def test_separable2():
a = Symbol('a')
eq6 = f(x)*x**2*f(x).diff(x) - f(x)**3 - 2*x**2*f(x).diff(x)
eq7 = f(x)**2 - 1 - (2*f(x) + x*f(x))*f(x).diff(x)
eq8 = x*log(x)*f(x).diff(x) + sqrt(1 + f(x)**2)
eq9 = exp(x + 1)*tan(f(x)) + cos(f(x))*f(x).diff(x)
eq10 = (x*cos(f(x)) + x**2*sin(f(x))*f(x).diff(x) -
a**2*sin(f(x))*f(x).diff(x))
sol6 = Eq(Integral((u - 2)/u**3, (u, f(x))),
C1 + Integral(x**(-2), x))
sol7 = Eq(-log(-1 + f(x)**2)/2, C1 - log(2 + x))
sol8 = Eq(asinh(f(x)), C1 - log(log(x)))
# integrate cannot handle the integral on the lhs (cos/tan)
sol9 = Eq(Integral(cos(u)/tan(u), (u, f(x))),
C1 + Integral(-exp(1)*exp(x), x))
sol10 = Eq(-log(cos(f(x))), C1 - log(- a**2 + x**2)/2)
assert dsolve(eq6, hint='separable_Integral').dummy_eq(sol6)
assert dsolve(eq7, hint='separable', simplify=False) == sol7
assert dsolve(eq8, hint='separable', simplify=False) == sol8
assert dsolve(eq9, hint='separable_Integral').dummy_eq(sol9)
assert dsolve(eq10, hint='separable', simplify=False) == sol10
assert checkodesol(eq7, sol7, order=1, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=1, solve_for_func=False)[0]
assert checkodesol(eq10, sol10, order=1, solve_for_func=False)[0]
def test_separable3():
eq11 = f(x).diff(x) - f(x)*tan(x)
eq12 = (x - 1)*cos(f(x))*f(x).diff(x) - 2*x*sin(f(x))
eq13 = f(x).diff(x) - f(x)*log(f(x))/tan(x)
sol11 = Eq(f(x), C1/cos(x))
sol12 = Eq(log(sin(f(x))), C1 + 2*x + 2*log(x - 1))
sol13 = Eq(log(log(f(x))), C1 + log(sin(x)))
assert dsolve(eq11, hint='separable') == sol11
assert dsolve(eq12, hint='separable', simplify=False) == sol12
assert dsolve(eq13, hint='separable', simplify=False) == sol13
assert checkodesol(eq11, sol11, order=1, solve_for_func=False)[0]
assert checkodesol(eq13, sol13, order=1, solve_for_func=False)[0]
def test_separable4():
# This has a slow integral (1/((1 + y**2)*atan(y))), so we isolate it.
eq14 = x*f(x).diff(x) + (1 + f(x)**2)*atan(f(x))
sol14 = Eq(log(atan(f(x))), C1 - log(x))
assert dsolve(eq14, hint='separable', simplify=False) == sol14
assert checkodesol(eq14, sol14, order=1, solve_for_func=False)[0]
def test_separable5():
eq15 = f(x).diff(x) + x*(f(x) + 1)
eq16 = exp(f(x)**2)*(x**2 + 2*x + 1) + (x*f(x) + f(x))*f(x).diff(x)
eq17 = f(x).diff(x) + f(x)
eq18 = sin(x)*cos(2*f(x)) + cos(x)*sin(2*f(x))*f(x).diff(x)
eq19 = (1 - x)*f(x).diff(x) - x*(f(x) + 1)
eq20 = f(x)*diff(f(x), x) + x - 3*x*f(x)**2
eq21 = f(x).diff(x) - exp(x + f(x))
sol15 = Eq(f(x), -1 + C1*exp(-x**2/2))
sol16 = Eq(-exp(-f(x)**2)/2, C1 - x - x**2/2)
sol17 = Eq(f(x), C1*exp(-x))
sol18 = Eq(-log(cos(2*f(x)))/2, C1 + log(cos(x)))
sol19 = Eq(f(x), (C1*exp(-x) - x + 1)/(x - 1))
sol20 = Eq(log(-1 + 3*f(x)**2)/6, C1 + x**2/2)
sol21 = Eq(-exp(-f(x)), C1 + exp(x))
assert dsolve(eq15, hint='separable') == sol15
assert dsolve(eq16, hint='separable', simplify=False) == sol16
assert dsolve(eq17, hint='separable') == sol17
assert dsolve(eq18, hint='separable', simplify=False) == sol18
assert dsolve(eq19, hint='separable') == sol19
assert dsolve(eq20, hint='separable', simplify=False) == sol20
assert dsolve(eq21, hint='separable', simplify=False) == sol21
assert checkodesol(eq15, sol15, order=1, solve_for_func=False)[0]
assert checkodesol(eq16, sol16, order=1, solve_for_func=False)[0]
assert checkodesol(eq17, sol17, order=1, solve_for_func=False)[0]
assert checkodesol(eq18, sol18, order=1, solve_for_func=False)[0]
assert checkodesol(eq19, sol19, order=1, solve_for_func=False)[0]
assert checkodesol(eq20, sol20, order=1, solve_for_func=False)[0]
assert checkodesol(eq21, sol21, order=1, solve_for_func=False)[0]
def test_separable_1_5_checkodesol():
eq12 = (x - 1)*cos(f(x))*f(x).diff(x) - 2*x*sin(f(x))
sol12 = Eq(-log(1 - cos(f(x))**2)/2, C1 - 2*x - 2*log(1 - x))
assert checkodesol(eq12, sol12, order=1, solve_for_func=False)[0]
def test_homogeneous_order():
assert homogeneous_order(exp(y/x) + tan(y/x), x, y) == 0
assert homogeneous_order(x**2 + sin(x)*cos(y), x, y) is None
assert homogeneous_order(x - y - x*sin(y/x), x, y) == 1
assert homogeneous_order((x*y + sqrt(x**4 + y**4) + x**2*(log(x) - log(y)))/
(pi*x**Rational(2, 3)*sqrt(y)**3), x, y) == Rational(-1, 6)
assert homogeneous_order(y/x*cos(y/x) - x/y*sin(y/x) + cos(y/x), x, y) == 0
assert homogeneous_order(f(x), x, f(x)) == 1
assert homogeneous_order(f(x)**2, x, f(x)) == 2
assert homogeneous_order(x*y*z, x, y) == 2
assert homogeneous_order(x*y*z, x, y, z) == 3
assert homogeneous_order(x**2*f(x)/sqrt(x**2 + f(x)**2), f(x)) is None
assert homogeneous_order(f(x, y)**2, x, f(x, y), y) == 2
assert homogeneous_order(f(x, y)**2, x, f(x), y) is None
assert homogeneous_order(f(x, y)**2, x, f(x, y)) is None
assert homogeneous_order(f(y, x)**2, x, y, f(x, y)) is None
assert homogeneous_order(f(y), f(x), x) is None
assert homogeneous_order(-f(x)/x + 1/sin(f(x)/ x), f(x), x) == 0
assert homogeneous_order(log(1/y) + log(x**2), x, y) is None
assert homogeneous_order(log(1/y) + log(x), x, y) == 0
assert homogeneous_order(log(x/y), x, y) == 0
assert homogeneous_order(2*log(1/y) + 2*log(x), x, y) == 0
a = Symbol('a')
assert homogeneous_order(a*log(1/y) + a*log(x), x, y) == 0
assert homogeneous_order(f(x).diff(x), x, y) is None
assert homogeneous_order(-f(x).diff(x) + x, x, y) is None
assert homogeneous_order(O(x), x, y) is None
assert homogeneous_order(x + O(x**2), x, y) is None
assert homogeneous_order(x**pi, x) == pi
assert homogeneous_order(x**x, x) is None
raises(ValueError, lambda: homogeneous_order(x*y))
@slow
def test_1st_homogeneous_coeff_ode():
# Type: First order homogeneous, y'=f(y/x)
eq1 = f(x)/x*cos(f(x)/x) - (x/f(x)*sin(f(x)/x) + cos(f(x)/x))*f(x).diff(x)
eq2 = x*f(x).diff(x) - f(x) - x*sin(f(x)/x)
eq3 = f(x) + (x*log(f(x)/x) - 2*x)*diff(f(x), x)
eq4 = 2*f(x)*exp(x/f(x)) + f(x)*f(x).diff(x) - 2*x*exp(x/f(x))*f(x).diff(x)
eq5 = 2*x**2*f(x) + f(x)**3 + (x*f(x)**2 - 2*x**3)*f(x).diff(x)
eq6 = x*exp(f(x)/x) - f(x)*sin(f(x)/x) + x*sin(f(x)/x)*f(x).diff(x)
eq7 = (x + sqrt(f(x)**2 - x*f(x)))*f(x).diff(x) - f(x)
eq8 = x + f(x) - (x - f(x))*f(x).diff(x)
sol1 = Eq(log(x), C1 - log(f(x)*sin(f(x)/x)/x))
sol2 = Eq(log(x), log(C1) + log(cos(f(x)/x) - 1)/2 - log(cos(f(x)/x) + 1)/2)
sol3 = Eq(f(x), -exp(C1)*LambertW(-x*exp(-C1 + 1)))
sol4 = Eq(log(f(x)), C1 - 2*exp(x/f(x)))
sol5 = Eq(f(x), exp(2*C1 + LambertW(-2*x**4*exp(-4*C1))/2)/x)
sol6 = Eq(log(x),
C1 + exp(-f(x)/x)*sin(f(x)/x)/2 + exp(-f(x)/x)*cos(f(x)/x)/2)
sol7 = Eq(log(f(x)), C1 - 2*sqrt(-x/f(x) + 1))
sol8 = Eq(log(x), C1 - log(sqrt(1 + f(x)**2/x**2)) + atan(f(x)/x))
assert dsolve(eq1, hint='1st_homogeneous_coeff_subs_dep_div_indep') == \
sol1
# indep_div_dep actually has a simpler solution for eq2,
# but it runs too slow
assert dsolve(eq2, hint='1st_homogeneous_coeff_subs_dep_div_indep',
simplify=False) == sol2
assert dsolve(eq3, hint='1st_homogeneous_coeff_best') == sol3
assert dsolve(eq4, hint='1st_homogeneous_coeff_best') == sol4
assert dsolve(eq5, hint='1st_homogeneous_coeff_best') == sol5
assert dsolve(eq6, hint='1st_homogeneous_coeff_subs_dep_div_indep') == \
sol6
assert dsolve(eq7, hint='1st_homogeneous_coeff_best') == sol7
assert dsolve(eq8, hint='1st_homogeneous_coeff_best') == sol8
# checks are below
@slow
def test_1st_homogeneous_coeff_ode_check134568():
# These are the checkodesols from test_homogeneous_coeff_ode().
eq1 = f(x)/x*cos(f(x)/x) - (x/f(x)*sin(f(x)/x) + cos(f(x)/x))*f(x).diff(x)
eq3 = f(x) + (x*log(f(x)/x) - 2*x)*diff(f(x), x)
eq4 = 2*f(x)*exp(x/f(x)) + f(x)*f(x).diff(x) - 2*x*exp(x/f(x))*f(x).diff(x)
eq5 = 2*x**2*f(x) + f(x)**3 + (x*f(x)**2 - 2*x**3)*f(x).diff(x)
eq6 = x*exp(f(x)/x) - f(x)*sin(f(x)/x) + x*sin(f(x)/x)*f(x).diff(x)
eq8 = x + f(x) - (x - f(x))*f(x).diff(x)
sol1 = Eq(f(x)*sin(f(x)/x), C1)
sol4 = Eq(log(C1*f(x)) + 2*exp(x/f(x)), 0)
sol3 = Eq(-f(x)/(1 + log(x/f(x))), C1)
sol5 = Eq(log(C1*x*sqrt(1/x)*sqrt(f(x))) + x**2/(2*f(x)**2), 0)
sol6 = Eq(-exp(-f(x)/x)*sin(f(x)/x)/2 + log(C1*x) -
cos(f(x)/x)*exp(-f(x)/x)/2, 0)
sol8 = Eq(-atan(f(x)/x) + log(C1*x*sqrt(1 + f(x)**2/x**2)), 0)
assert checkodesol(eq1, sol1, order=1, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=1, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=1, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=1, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=1, solve_for_func=False)[0]
def test_1st_homogeneous_coeff_ode_check2():
eq2 = x*f(x).diff(x) - f(x) - x*sin(f(x)/x)
sol2 = Eq(x/tan(f(x)/(2*x)), C1)
assert checkodesol(eq2, sol2, order=1, solve_for_func=False)[0]
@XFAIL
def test_1st_homogeneous_coeff_ode_check3():
skip('This is a known issue.')
# checker cannot determine that the following expression is zero:
# (False,
# x*(log(exp(-LambertW(C1*x))) +
# LambertW(C1*x))*exp(-LambertW(C1*x) + 1))
# This is blocked by issue 5080.
eq3 = f(x) + (x*log(f(x)/x) - 2*x)*diff(f(x), x)
sol3a = Eq(f(x), x*exp(1 - LambertW(C1*x)))
assert checkodesol(eq3, sol3a, solve_for_func=True)[0]
# Checker can't verify this form either
# (False,
# C1*(log(C1*LambertW(C2*x)/x) + LambertW(C2*x) - 1)*LambertW(C2*x))
# It is because a = W(a)*exp(W(a)), so log(a) == log(W(a)) + W(a) and C2 =
# -E/C1 (which can be verified by solving with simplify=False).
sol3b = Eq(f(x), C1*LambertW(C2*x))
assert checkodesol(eq3, sol3b, solve_for_func=True)[0]
def test_1st_homogeneous_coeff_ode_check7():
eq7 = (x + sqrt(f(x)**2 - x*f(x)))*f(x).diff(x) - f(x)
sol7 = Eq(log(C1*f(x)) + 2*sqrt(1 - x/f(x)), 0)
assert checkodesol(eq7, sol7, order=1, solve_for_func=False)[0]
def test_1st_homogeneous_coeff_ode2():
eq1 = f(x).diff(x) - f(x)/x + 1/sin(f(x)/x)
eq2 = x**2 + f(x)**2 - 2*x*f(x)*f(x).diff(x)
eq3 = x*exp(f(x)/x) + f(x) - x*f(x).diff(x)
sol1 = [Eq(f(x), x*(-acos(C1 + log(x)) + 2*pi)), Eq(f(x), x*acos(C1 + log(x)))]
sol2 = Eq(log(f(x)), log(C1) + log(x/f(x)) - log(x**2/f(x)**2 - 1))
sol3 = Eq(f(x), log((1/(C1 - log(x)))**x))
# specific hints are applied for speed reasons
assert dsolve(eq1, hint='1st_homogeneous_coeff_subs_dep_div_indep') == sol1
assert dsolve(eq2, hint='1st_homogeneous_coeff_best', simplify=False) == sol2
assert dsolve(eq3, hint='1st_homogeneous_coeff_subs_dep_div_indep') == sol3
assert checkodesol(eq1, sol1, order=1, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=1, solve_for_func=False)[0]
# test for eq3 is in test_1st_homogeneous_coeff_ode2_check3 below
def test_1st_homogeneous_coeff_ode2_check3():
eq3 = x*exp(f(x)/x) + f(x) - x*f(x).diff(x)
sol3 = Eq(f(x), log(log(C1/x)**(-x)))
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
def test_1st_homogeneous_coeff_ode_check9():
_u2 = Dummy('u2')
__a = Dummy('a')
eq9 = f(x)**2 + (x*sqrt(f(x)**2 - x**2) - x*f(x))*f(x).diff(x)
sol9 = Eq(-Integral(-1/(-(1 - sqrt(1 - _u2**2))*_u2 + _u2), (_u2, __a,
x/f(x))) + log(C1*f(x)), 0)
assert checkodesol(eq9, sol9, order=1, solve_for_func=False)[0]
def test_1st_homogeneous_coeff_ode3():
# The standard integration engine cannot handle one of the integrals
# involved (see issue 4551). meijerg code comes up with an answer, but in
# unconventional form.
# checkodesol fails for this equation, so its test is in
# test_1st_homogeneous_coeff_ode_check9 above. It has to compare string
# expressions because u2 is a dummy variable.
eq = f(x)**2 + (x*sqrt(f(x)**2 - x**2) - x*f(x))*f(x).diff(x)
sol = Eq(log(f(x)), C1 + Piecewise(
(acosh(f(x)/x), abs(f(x)**2)/x**2 > 1),
(-I*asin(f(x)/x), True)))
assert dsolve(eq, hint='1st_homogeneous_coeff_subs_indep_div_dep') == sol
def test_1st_homogeneous_coeff_corner_case():
eq1 = f(x).diff(x) - f(x)/x
c1 = classify_ode(eq1, f(x))
eq2 = x*f(x).diff(x) - f(x)
c2 = classify_ode(eq2, f(x))
sdi = "1st_homogeneous_coeff_subs_dep_div_indep"
sid = "1st_homogeneous_coeff_subs_indep_div_dep"
assert sid not in c1 and sdi not in c1
assert sid not in c2 and sdi not in c2
@slow
def test_nth_linear_constant_coeff_homogeneous():
# From Exercise 20, in Ordinary Differential Equations,
# Tenenbaum and Pollard, pg. 220
a = Symbol('a', positive=True)
k = Symbol('k', real=True)
eq1 = f(x).diff(x, 2) + 2*f(x).diff(x)
eq2 = f(x).diff(x, 2) - 3*f(x).diff(x) + 2*f(x)
eq3 = f(x).diff(x, 2) - f(x)
eq4 = f(x).diff(x, 3) + f(x).diff(x, 2) - 6*f(x).diff(x)
eq5 = 6*f(x).diff(x, 2) - 11*f(x).diff(x) + 4*f(x)
eq6 = Eq(f(x).diff(x, 2) + 2*f(x).diff(x) - f(x), 0)
eq7 = diff(f(x), x, 3) + diff(f(x), x, 2) - 10*diff(f(x), x) - 6*f(x)
eq8 = f(x).diff(x, 4) - f(x).diff(x, 3) - 4*f(x).diff(x, 2) + \
4*f(x).diff(x)
eq9 = f(x).diff(x, 4) + 4*f(x).diff(x, 3) + f(x).diff(x, 2) - \
4*f(x).diff(x) - 2*f(x)
eq10 = f(x).diff(x, 4) - a**2*f(x)
eq11 = f(x).diff(x, 2) - 2*k*f(x).diff(x) - 2*f(x)
eq12 = f(x).diff(x, 2) + 4*k*f(x).diff(x) - 12*k**2*f(x)
eq13 = f(x).diff(x, 4)
eq14 = f(x).diff(x, 2) + 4*f(x).diff(x) + 4*f(x)
eq15 = 3*f(x).diff(x, 3) + 5*f(x).diff(x, 2) + f(x).diff(x) - f(x)
eq16 = f(x).diff(x, 3) - 6*f(x).diff(x, 2) + 12*f(x).diff(x) - 8*f(x)
eq17 = f(x).diff(x, 2) - 2*a*f(x).diff(x) + a**2*f(x)
eq18 = f(x).diff(x, 4) + 3*f(x).diff(x, 3)
eq19 = f(x).diff(x, 4) - 2*f(x).diff(x, 2)
eq20 = f(x).diff(x, 4) + 2*f(x).diff(x, 3) - 11*f(x).diff(x, 2) - \
12*f(x).diff(x) + 36*f(x)
eq21 = 36*f(x).diff(x, 4) - 37*f(x).diff(x, 2) + 4*f(x).diff(x) + 5*f(x)
eq22 = f(x).diff(x, 4) - 8*f(x).diff(x, 2) + 16*f(x)
eq23 = f(x).diff(x, 2) - 2*f(x).diff(x) + 5*f(x)
eq24 = f(x).diff(x, 2) - f(x).diff(x) + f(x)
eq25 = f(x).diff(x, 4) + 5*f(x).diff(x, 2) + 6*f(x)
eq26 = f(x).diff(x, 2) - 4*f(x).diff(x) + 20*f(x)
eq27 = f(x).diff(x, 4) + 4*f(x).diff(x, 2) + 4*f(x)
eq28 = f(x).diff(x, 3) + 8*f(x)
eq29 = f(x).diff(x, 4) + 4*f(x).diff(x, 2)
eq30 = f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x)
eq31 = f(x).diff(x, 4) + f(x).diff(x, 2) + f(x)
eq32 = f(x).diff(x, 4) + 4*f(x).diff(x, 2) + f(x)
sol1 = Eq(f(x), C1 + C2*exp(-2*x))
sol2 = Eq(f(x), (C1 + C2*exp(x))*exp(x))
sol3 = Eq(f(x), C1*exp(x) + C2*exp(-x))
sol4 = Eq(f(x), C1 + C2*exp(-3*x) + C3*exp(2*x))
sol5 = Eq(f(x), C1*exp(x/2) + C2*exp(4*x/3))
sol6 = Eq(f(x), C1*exp(x*(-1 + sqrt(2))) + C2*exp(x*(-sqrt(2) - 1)))
sol7 = Eq(f(x),
C1*exp(3*x) + C2*exp(x*(-2 - sqrt(2))) + C3*exp(x*(-2 + sqrt(2))))
sol8 = Eq(f(x), C1 + C2*exp(x) + C3*exp(-2*x) + C4*exp(2*x))
sol9 = Eq(f(x),
C1*exp(x) + C2*exp(-x) + C3*exp(x*(-2 + sqrt(2))) +
C4*exp(x*(-2 - sqrt(2))))
sol10 = Eq(f(x),
C1*sin(x*sqrt(a)) + C2*cos(x*sqrt(a)) + C3*exp(x*sqrt(a)) +
C4*exp(-x*sqrt(a)))
sol11 = Eq(f(x),
C1*exp(x*(k - sqrt(k**2 + 2))) + C2*exp(x*(k + sqrt(k**2 + 2))))
sol12 = Eq(f(x), C1*exp(-6*k*x) + C2*exp(2*k*x))
sol13 = Eq(f(x), C1 + C2*x + C3*x**2 + C4*x**3)
sol14 = Eq(f(x), (C1 + C2*x)*exp(-2*x))
sol15 = Eq(f(x), (C1 + C2*x)*exp(-x) + C3*exp(x/3))
sol16 = Eq(f(x), (C1 + C2*x + C3*x**2)*exp(2*x))
sol17 = Eq(f(x), (C1 + C2*x)*exp(a*x))
sol18 = Eq(f(x), C1 + C2*x + C3*x**2 + C4*exp(-3*x))
sol19 = Eq(f(x), C1 + C2*x + C3*exp(x*sqrt(2)) + C4*exp(-x*sqrt(2)))
sol20 = Eq(f(x), (C1 + C2*x)*exp(-3*x) + (C3 + C4*x)*exp(2*x))
sol21 = Eq(f(x), C1*exp(x/2) + C2*exp(-x) + C3*exp(-x/3) + C4*exp(5*x/6))
sol22 = Eq(f(x), (C1 + C2*x)*exp(-2*x) + (C3 + C4*x)*exp(2*x))
sol23 = Eq(f(x), (C1*sin(2*x) + C2*cos(2*x))*exp(x))
sol24 = Eq(f(x), (C1*sin(x*sqrt(3)/2) + C2*cos(x*sqrt(3)/2))*exp(x/2))
sol25 = Eq(f(x),
C1*cos(x*sqrt(3)) + C2*sin(x*sqrt(3)) + C3*sin(x*sqrt(2)) +
C4*cos(x*sqrt(2)))
sol26 = Eq(f(x), (C1*sin(4*x) + C2*cos(4*x))*exp(2*x))
sol27 = Eq(f(x), (C1 + C2*x)*sin(x*sqrt(2)) + (C3 + C4*x)*cos(x*sqrt(2)))
sol28 = Eq(f(x),
(C1*sin(x*sqrt(3)) + C2*cos(x*sqrt(3)))*exp(x) + C3*exp(-2*x))
sol29 = Eq(f(x), C1 + C2*sin(2*x) + C3*cos(2*x) + C4*x)
sol30 = Eq(f(x), C1 + (C2 + C3*x)*sin(x) + (C4 + C5*x)*cos(x))
sol31 = Eq(f(x), (C1*sin(sqrt(3)*x/2) + C2*cos(sqrt(3)*x/2))/sqrt(exp(x))
+ (C3*sin(sqrt(3)*x/2) + C4*cos(sqrt(3)*x/2))*sqrt(exp(x)))
sol32 = Eq(f(x), C1*sin(x*sqrt(-sqrt(3) + 2)) + C2*sin(x*sqrt(sqrt(3) + 2))
+ C3*cos(x*sqrt(-sqrt(3) + 2)) + C4*cos(x*sqrt(sqrt(3) + 2)))
sol1s = constant_renumber(sol1, 'C', 1, 2)
sol2s = constant_renumber(sol2, 'C', 1, 2)
sol3s = constant_renumber(sol3, 'C', 1, 2)
sol4s = constant_renumber(sol4, 'C', 1, 3)
sol5s = constant_renumber(sol5, 'C', 1, 2)
sol6s = constant_renumber(sol6, 'C', 1, 2)
sol7s = constant_renumber(sol7, 'C', 1, 3)
sol8s = constant_renumber(sol8, 'C', 1, 4)
sol9s = constant_renumber(sol9, 'C', 1, 4)
sol10s = constant_renumber(sol10, 'C', 1, 4)
sol11s = constant_renumber(sol11, 'C', 1, 2)
sol12s = constant_renumber(sol12, 'C', 1, 2)
sol13s = constant_renumber(sol13, 'C', 1, 4)
sol14s = constant_renumber(sol14, 'C', 1, 2)
sol15s = constant_renumber(sol15, 'C', 1, 3)
sol16s = constant_renumber(sol16, 'C', 1, 3)
sol17s = constant_renumber(sol17, 'C', 1, 2)
sol18s = constant_renumber(sol18, 'C', 1, 4)
sol19s = constant_renumber(sol19, 'C', 1, 4)
sol20s = constant_renumber(sol20, 'C', 1, 4)
sol21s = constant_renumber(sol21, 'C', 1, 4)
sol22s = constant_renumber(sol22, 'C', 1, 4)
sol23s = constant_renumber(sol23, 'C', 1, 2)
sol24s = constant_renumber(sol24, 'C', 1, 2)
sol25s = constant_renumber(sol25, 'C', 1, 4)
sol26s = constant_renumber(sol26, 'C', 1, 2)
sol27s = constant_renumber(sol27, 'C', 1, 4)
sol28s = constant_renumber(sol28, 'C', 1, 3)
sol29s = constant_renumber(sol29, 'C', 1, 4)
sol30s = constant_renumber(sol30, 'C', 1, 5)
assert dsolve(eq1) in (sol1, sol1s)
assert dsolve(eq2) in (sol2, sol2s)
assert dsolve(eq3) in (sol3, sol3s)
assert dsolve(eq4) in (sol4, sol4s)
assert dsolve(eq5) in (sol5, sol5s)
assert dsolve(eq6) in (sol6, sol6s)
assert dsolve(eq7) in (sol7, sol7s)
assert dsolve(eq8) in (sol8, sol8s)
assert dsolve(eq9) in (sol9, sol9s)
assert dsolve(eq10) in (sol10, sol10s)
assert dsolve(eq11) in (sol11, sol11s)
assert dsolve(eq12) in (sol12, sol12s)
assert dsolve(eq13) in (sol13, sol13s)
assert dsolve(eq14) in (sol14, sol14s)
assert dsolve(eq15) in (sol15, sol15s)
assert dsolve(eq16) in (sol16, sol16s)
assert dsolve(eq17) in (sol17, sol17s)
assert dsolve(eq18) in (sol18, sol18s)
assert dsolve(eq19) in (sol19, sol19s)
assert dsolve(eq20) in (sol20, sol20s)
assert dsolve(eq21) in (sol21, sol21s)
assert dsolve(eq22) in (sol22, sol22s)
assert dsolve(eq23) in (sol23, sol23s)
assert dsolve(eq24) in (sol24, sol24s)
assert dsolve(eq25) in (sol25, sol25s)
assert dsolve(eq26) in (sol26, sol26s)
assert dsolve(eq27) in (sol27, sol27s)
assert dsolve(eq28) in (sol28, sol28s)
assert dsolve(eq29) in (sol29, sol29s)
assert dsolve(eq30) in (sol30, sol30s)
assert dsolve(eq31) in (sol31,)
assert dsolve(eq32) in (sol32,)
assert checkodesol(eq1, sol1, order=2, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=2, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=2, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=3, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=2, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=2, solve_for_func=False)[0]
assert checkodesol(eq7, sol7, order=3, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=4, solve_for_func=False)[0]
assert checkodesol(eq9, sol9, order=4, solve_for_func=False)[0]
assert checkodesol(eq10, sol10, order=4, solve_for_func=False)[0]
assert checkodesol(eq11, sol11, order=2, solve_for_func=False)[0]
assert checkodesol(eq12, sol12, order=2, solve_for_func=False)[0]
assert checkodesol(eq13, sol13, order=4, solve_for_func=False)[0]
assert checkodesol(eq14, sol14, order=2, solve_for_func=False)[0]
assert checkodesol(eq15, sol15, order=3, solve_for_func=False)[0]
assert checkodesol(eq16, sol16, order=3, solve_for_func=False)[0]
assert checkodesol(eq17, sol17, order=2, solve_for_func=False)[0]
assert checkodesol(eq18, sol18, order=4, solve_for_func=False)[0]
assert checkodesol(eq19, sol19, order=4, solve_for_func=False)[0]
assert checkodesol(eq20, sol20, order=4, solve_for_func=False)[0]
assert checkodesol(eq21, sol21, order=4, solve_for_func=False)[0]
assert checkodesol(eq22, sol22, order=4, solve_for_func=False)[0]
assert checkodesol(eq23, sol23, order=2, solve_for_func=False)[0]
assert checkodesol(eq24, sol24, order=2, solve_for_func=False)[0]
assert checkodesol(eq25, sol25, order=4, solve_for_func=False)[0]
assert checkodesol(eq26, sol26, order=2, solve_for_func=False)[0]
assert checkodesol(eq27, sol27, order=4, solve_for_func=False)[0]
assert checkodesol(eq28, sol28, order=3, solve_for_func=False)[0]
assert checkodesol(eq29, sol29, order=4, solve_for_func=False)[0]
assert checkodesol(eq30, sol30, order=5, solve_for_func=False)[0]
assert checkodesol(eq31, sol31, order=4, solve_for_func=False)[0]
assert checkodesol(eq32, sol32, order=4, solve_for_func=False)[0]
# Issue #15237
eqn = Derivative(x*f(x), x, x, x)
hint = 'nth_linear_constant_coeff_homogeneous'
raises(ValueError, lambda: dsolve(eqn, f(x), hint, prep=True))
raises(ValueError, lambda: dsolve(eqn, f(x), hint, prep=False))
def test_nth_linear_constant_coeff_homogeneous_rootof():
# One real root, two complex conjugate pairs
eq = f(x).diff(x, 5) + 11*f(x).diff(x) - 2*f(x)
r1, r2, r3, r4, r5 = [rootof(x**5 + 11*x - 2, n) for n in range(5)]
sol = Eq(f(x),
C5*exp(r1*x)
+ exp(re(r2)*x) * (C1*sin(im(r2)*x) + C2*cos(im(r2)*x))
+ exp(re(r4)*x) * (C3*sin(im(r4)*x) + C4*cos(im(r4)*x))
)
assert dsolve(eq) == sol
# Three real roots, one complex conjugate pair
eq = f(x).diff(x,5) - 3*f(x).diff(x) + f(x)
r1, r2, r3, r4, r5 = [rootof(x**5 - 3*x + 1, n) for n in range(5)]
sol = Eq(f(x),
C3*exp(r1*x) + C4*exp(r2*x) + C5*exp(r3*x)
+ exp(re(r4)*x) * (C1*sin(im(r4)*x) + C2*cos(im(r4)*x))
)
assert dsolve(eq) == sol
# Five distinct real roots
eq = f(x).diff(x,5) - 100*f(x).diff(x,3) + 1000*f(x).diff(x) + f(x)
r1, r2, r3, r4, r5 = [rootof(x**5 - 100*x**3 + 1000*x + 1, n) for n in range(5)]
sol = Eq(f(x), C1*exp(r1*x) + C2*exp(r2*x) + C3*exp(r3*x) + C4*exp(r4*x) + C5*exp(r5*x))
assert dsolve(eq) == sol
# Rational root and unsolvable quintic
eq = f(x).diff(x, 6) - 6*f(x).diff(x, 5) + 5*f(x).diff(x, 4) + 10*f(x).diff(x) - 50 * f(x)
r2, r3, r4, r5, r6 = [rootof(x**5 - x**4 + 10, n) for n in range(5)]
sol = Eq(f(x),
C5*exp(5*x)
+ C6*exp(x*r2)
+ exp(re(r3)*x) * (C1*sin(im(r3)*x) + C2*cos(im(r3)*x))
+ exp(re(r5)*x) * (C3*sin(im(r5)*x) + C4*cos(im(r5)*x))
)
assert dsolve(eq) == sol
# Five double roots (this is (x**5 - x + 1)**2)
eq = f(x).diff(x, 10) - 2*f(x).diff(x, 6) + 2*f(x).diff(x, 5) + f(x).diff(x, 2) - 2*f(x).diff(x, 1) + f(x)
r1, r2, r3, r4, r5 = [rootof(x**5 - x + 1, n) for n in range(5)]
sol = Eq(f(x),
(C1 + C2 *x)*exp(r1*x)
+ exp(re(r2)*x) * ((C3 + C4*x)*sin(im(r2)*x) + (C5 + C6 *x)*cos(im(r2)*x))
+ exp(re(r4)*x) * ((C7 + C8*x)*sin(im(r4)*x) + (C9 + C10*x)*cos(im(r4)*x))
)
assert dsolve(eq) == sol
def test_nth_linear_constant_coeff_homogeneous_irrational():
our_hint='nth_linear_constant_coeff_homogeneous'
eq = Eq(sqrt(2) * f(x).diff(x,x,x) + f(x).diff(x), 0)
sol = Eq(f(x), C1 + C2*sin(2**(S(3)/4)*x/2) + C3*cos(2**(S(3)/4)*x/2))
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint) == sol
assert dsolve(eq, f(x)) == sol
assert checkodesol(eq, sol, order=3, solve_for_func=False)[0]
E = exp(1)
eq = Eq(E * f(x).diff(x,x,x) + f(x).diff(x), 0)
sol = Eq(f(x), C1 + C2*sin(x/sqrt(E)) + C3*cos(x/sqrt(E)))
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint) == sol
assert dsolve(eq, f(x)) == sol
assert checkodesol(eq, sol, order=3, solve_for_func=False)[0]
eq = Eq(pi * f(x).diff(x,x,x) + f(x).diff(x), 0)
sol = Eq(f(x), C1 + C2*sin(x/sqrt(pi)) + C3*cos(x/sqrt(pi)))
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint) == sol
assert dsolve(eq, f(x)) == sol
assert checkodesol(eq, sol, order=3, solve_for_func=False)[0]
eq = Eq(I * f(x).diff(x,x,x) + f(x).diff(x), 0)
sol = Eq(f(x), C1 + C2*exp(-sqrt(I)*x) + C3*exp(sqrt(I)*x))
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint) == sol
assert dsolve(eq, f(x)) == sol
assert checkodesol(eq, sol, order=3, solve_for_func=False)[0]
@XFAIL
@slow
def test_nth_linear_constant_coeff_homogeneous_rootof_sol():
if ON_TRAVIS:
skip("Too slow for travis.")
eq = f(x).diff(x, 5) + 11*f(x).diff(x) - 2*f(x)
sol = Eq(f(x),
C1*exp(x*rootof(x**5 + 11*x - 2, 0)) +
C2*exp(x*rootof(x**5 + 11*x - 2, 1)) +
C3*exp(x*rootof(x**5 + 11*x - 2, 2)) +
C4*exp(x*rootof(x**5 + 11*x - 2, 3)) +
C5*exp(x*rootof(x**5 + 11*x - 2, 4)))
assert checkodesol(eq, sol, order=5, solve_for_func=False)[0]
@XFAIL
def test_noncircularized_real_imaginary_parts():
# If this passes, lines numbered 3878-3882 (at the time of this commit)
# of sympy/solvers/ode.py for nth_linear_constant_coeff_homogeneous
# should be removed.
y = sqrt(1+x)
i, r = im(y), re(y)
assert not (i.has(atan2) and r.has(atan2))
@XFAIL
def test_collect_respecting_exponentials():
# If this test passes, lines 1306-1311 (at the time of this commit)
# of sympy/solvers/ode.py should be removed.
sol = 1 + exp(x/2)
assert sol == collect( sol, exp(x/3))
def test_undetermined_coefficients_match():
assert _undetermined_coefficients_match(g(x), x) == {'test': False}
assert _undetermined_coefficients_match(sin(2*x + sqrt(5)), x) == \
{'test': True, 'trialset':
set([cos(2*x + sqrt(5)), sin(2*x + sqrt(5))])}
assert _undetermined_coefficients_match(sin(x)*cos(x), x) == \
{'test': False}
s = set([cos(x), x*cos(x), x**2*cos(x), x**2*sin(x), x*sin(x), sin(x)])
assert _undetermined_coefficients_match(sin(x)*(x**2 + x + 1), x) == \
{'test': True, 'trialset': s}
assert _undetermined_coefficients_match(
sin(x)*x**2 + sin(x)*x + sin(x), x) == {'test': True, 'trialset': s}
assert _undetermined_coefficients_match(
exp(2*x)*sin(x)*(x**2 + x + 1), x
) == {
'test': True, 'trialset': set([exp(2*x)*sin(x), x**2*exp(2*x)*sin(x),
cos(x)*exp(2*x), x**2*cos(x)*exp(2*x), x*cos(x)*exp(2*x),
x*exp(2*x)*sin(x)])}
assert _undetermined_coefficients_match(1/sin(x), x) == {'test': False}
assert _undetermined_coefficients_match(log(x), x) == {'test': False}
assert _undetermined_coefficients_match(2**(x)*(x**2 + x + 1), x) == \
{'test': True, 'trialset': set([2**x, x*2**x, x**2*2**x])}
assert _undetermined_coefficients_match(x**y, x) == {'test': False}
assert _undetermined_coefficients_match(exp(x)*exp(2*x + 1), x) == \
{'test': True, 'trialset': set([exp(1 + 3*x)])}
assert _undetermined_coefficients_match(sin(x)*(x**2 + x + 1), x) == \
{'test': True, 'trialset': set([x*cos(x), x*sin(x), x**2*cos(x),
x**2*sin(x), cos(x), sin(x)])}
assert _undetermined_coefficients_match(sin(x)*(x + sin(x)), x) == \
{'test': False}
assert _undetermined_coefficients_match(sin(x)*(x + sin(2*x)), x) == \
{'test': False}
assert _undetermined_coefficients_match(sin(x)*tan(x), x) == \
{'test': False}
assert _undetermined_coefficients_match(
x**2*sin(x)*exp(x) + x*sin(x) + x, x
) == {
'test': True, 'trialset': set([x**2*cos(x)*exp(x), x, cos(x), S(1),
exp(x)*sin(x), sin(x), x*exp(x)*sin(x), x*cos(x), x*cos(x)*exp(x),
x*sin(x), cos(x)*exp(x), x**2*exp(x)*sin(x)])}
assert _undetermined_coefficients_match(4*x*sin(x - 2), x) == {
'trialset': set([x*cos(x - 2), x*sin(x - 2), cos(x - 2), sin(x - 2)]),
'test': True,
}
assert _undetermined_coefficients_match(2**x*x, x) == \
{'test': True, 'trialset': set([2**x, x*2**x])}
assert _undetermined_coefficients_match(2**x*exp(2*x), x) == \
{'test': True, 'trialset': set([2**x*exp(2*x)])}
assert _undetermined_coefficients_match(exp(-x)/x, x) == \
{'test': False}
# Below are from Ordinary Differential Equations,
# Tenenbaum and Pollard, pg. 231
assert _undetermined_coefficients_match(S(4), x) == \
{'test': True, 'trialset': set([S(1)])}
assert _undetermined_coefficients_match(12*exp(x), x) == \
{'test': True, 'trialset': set([exp(x)])}
assert _undetermined_coefficients_match(exp(I*x), x) == \
{'test': True, 'trialset': set([exp(I*x)])}
assert _undetermined_coefficients_match(sin(x), x) == \
{'test': True, 'trialset': set([cos(x), sin(x)])}
assert _undetermined_coefficients_match(cos(x), x) == \
{'test': True, 'trialset': set([cos(x), sin(x)])}
assert _undetermined_coefficients_match(8 + 6*exp(x) + 2*sin(x), x) == \
{'test': True, 'trialset': set([S(1), cos(x), sin(x), exp(x)])}
assert _undetermined_coefficients_match(x**2, x) == \
{'test': True, 'trialset': set([S(1), x, x**2])}
assert _undetermined_coefficients_match(9*x*exp(x) + exp(-x), x) == \
{'test': True, 'trialset': set([x*exp(x), exp(x), exp(-x)])}
assert _undetermined_coefficients_match(2*exp(2*x)*sin(x), x) == \
{'test': True, 'trialset': set([exp(2*x)*sin(x), cos(x)*exp(2*x)])}
assert _undetermined_coefficients_match(x - sin(x), x) == \
{'test': True, 'trialset': set([S(1), x, cos(x), sin(x)])}
assert _undetermined_coefficients_match(x**2 + 2*x, x) == \
{'test': True, 'trialset': set([S(1), x, x**2])}
assert _undetermined_coefficients_match(4*x*sin(x), x) == \
{'test': True, 'trialset': set([x*cos(x), x*sin(x), cos(x), sin(x)])}
assert _undetermined_coefficients_match(x*sin(2*x), x) == \
{'test': True, 'trialset':
set([x*cos(2*x), x*sin(2*x), cos(2*x), sin(2*x)])}
assert _undetermined_coefficients_match(x**2*exp(-x), x) == \
{'test': True, 'trialset': set([x*exp(-x), x**2*exp(-x), exp(-x)])}
assert _undetermined_coefficients_match(2*exp(-x) - x**2*exp(-x), x) == \
{'test': True, 'trialset': set([x*exp(-x), x**2*exp(-x), exp(-x)])}
assert _undetermined_coefficients_match(exp(-2*x) + x**2, x) == \
{'test': True, 'trialset': set([S(1), x, x**2, exp(-2*x)])}
assert _undetermined_coefficients_match(x*exp(-x), x) == \
{'test': True, 'trialset': set([x*exp(-x), exp(-x)])}
assert _undetermined_coefficients_match(x + exp(2*x), x) == \
{'test': True, 'trialset': set([S(1), x, exp(2*x)])}
assert _undetermined_coefficients_match(sin(x) + exp(-x), x) == \
{'test': True, 'trialset': set([cos(x), sin(x), exp(-x)])}
assert _undetermined_coefficients_match(exp(x), x) == \
{'test': True, 'trialset': set([exp(x)])}
# converted from sin(x)**2
assert _undetermined_coefficients_match(S(1)/2 - cos(2*x)/2, x) == \
{'test': True, 'trialset': set([S(1), cos(2*x), sin(2*x)])}
# converted from exp(2*x)*sin(x)**2
assert _undetermined_coefficients_match(
exp(2*x)*(S(1)/2 + cos(2*x)/2), x
) == {
'test': True, 'trialset': set([exp(2*x)*sin(2*x), cos(2*x)*exp(2*x),
exp(2*x)])}
assert _undetermined_coefficients_match(2*x + sin(x) + cos(x), x) == \
{'test': True, 'trialset': set([S(1), x, cos(x), sin(x)])}
# converted from sin(2*x)*sin(x)
assert _undetermined_coefficients_match(cos(x)/2 - cos(3*x)/2, x) == \
{'test': True, 'trialset': set([cos(x), cos(3*x), sin(x), sin(3*x)])}
assert _undetermined_coefficients_match(cos(x**2), x) == {'test': False}
assert _undetermined_coefficients_match(2**(x**2), x) == {'test': False}
@slow
def test_nth_linear_constant_coeff_undetermined_coefficients():
hint = 'nth_linear_constant_coeff_undetermined_coefficients'
g = exp(-x)
f2 = f(x).diff(x, 2)
c = 3*f(x).diff(x, 3) + 5*f2 + f(x).diff(x) - f(x) - x
eq1 = c - x*g
eq2 = c - g
# 3-27 below are from Ordinary Differential Equations,
# Tenenbaum and Pollard, pg. 231
eq3 = f2 + 3*f(x).diff(x) + 2*f(x) - 4
eq4 = f2 + 3*f(x).diff(x) + 2*f(x) - 12*exp(x)
eq5 = f2 + 3*f(x).diff(x) + 2*f(x) - exp(I*x)
eq6 = f2 + 3*f(x).diff(x) + 2*f(x) - sin(x)
eq7 = f2 + 3*f(x).diff(x) + 2*f(x) - cos(x)
eq8 = f2 + 3*f(x).diff(x) + 2*f(x) - (8 + 6*exp(x) + 2*sin(x))
eq9 = f2 + f(x).diff(x) + f(x) - x**2
eq10 = f2 - 2*f(x).diff(x) - 8*f(x) - 9*x*exp(x) - 10*exp(-x)
eq11 = f2 - 3*f(x).diff(x) - 2*exp(2*x)*sin(x)
eq12 = f(x).diff(x, 4) - 2*f2 + f(x) - x + sin(x)
eq13 = f2 + f(x).diff(x) - x**2 - 2*x
eq14 = f2 + f(x).diff(x) - x - sin(2*x)
eq15 = f2 + f(x) - 4*x*sin(x)
eq16 = f2 + 4*f(x) - x*sin(2*x)
eq17 = f2 + 2*f(x).diff(x) + f(x) - x**2*exp(-x)
eq18 = f(x).diff(x, 3) + 3*f2 + 3*f(x).diff(x) + f(x) - 2*exp(-x) + \
x**2*exp(-x)
eq19 = f2 + 3*f(x).diff(x) + 2*f(x) - exp(-2*x) - x**2
eq20 = f2 - 3*f(x).diff(x) + 2*f(x) - x*exp(-x)
eq21 = f2 + f(x).diff(x) - 6*f(x) - x - exp(2*x)
eq22 = f2 + f(x) - sin(x) - exp(-x)
eq23 = f(x).diff(x, 3) - 3*f2 + 3*f(x).diff(x) - f(x) - exp(x)
# sin(x)**2
eq24 = f2 + f(x) - S(1)/2 - cos(2*x)/2
# exp(2*x)*sin(x)**2
eq25 = f(x).diff(x, 3) - f(x).diff(x) - exp(2*x)*(S(1)/2 - cos(2*x)/2)
eq26 = (f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x) - 2*x -
sin(x) - cos(x))
# sin(2*x)*sin(x), skip 3127 for now, match bug
eq27 = f2 + f(x) - cos(x)/2 + cos(3*x)/2
eq28 = f(x).diff(x) - 1
sol1 = Eq(f(x),
-1 - x + (C1 + C2*x - 3*x**2/32 - x**3/24)*exp(-x) + C3*exp(x/3))
sol2 = Eq(f(x), -1 - x + (C1 + C2*x - x**2/8)*exp(-x) + C3*exp(x/3))
sol3 = Eq(f(x), 2 + C1*exp(-x) + C2*exp(-2*x))
sol4 = Eq(f(x), 2*exp(x) + C1*exp(-x) + C2*exp(-2*x))
sol5 = Eq(f(x), C1*exp(-2*x) + C2*exp(-x) + exp(I*x)/10 - 3*I*exp(I*x)/10)
sol6 = Eq(f(x), -3*cos(x)/10 + sin(x)/10 + C1*exp(-x) + C2*exp(-2*x))
sol7 = Eq(f(x), cos(x)/10 + 3*sin(x)/10 + C1*exp(-x) + C2*exp(-2*x))
sol8 = Eq(f(x),
4 - 3*cos(x)/5 + sin(x)/5 + exp(x) + C1*exp(-x) + C2*exp(-2*x))
sol9 = Eq(f(x),
-2*x + x**2 + (C1*sin(x*sqrt(3)/2) + C2*cos(x*sqrt(3)/2))*exp(-x/2))
sol10 = Eq(f(x), -x*exp(x) - 2*exp(-x) + C1*exp(-2*x) + C2*exp(4*x))
sol11 = Eq(f(x), C1 + C2*exp(3*x) + (-3*sin(x) - cos(x))*exp(2*x)/5)
sol12 = Eq(f(x), x - sin(x)/4 + (C1 + C2*x)*exp(-x) + (C3 + C4*x)*exp(x))
sol13 = Eq(f(x), C1 + x**3/3 + C2*exp(-x))
sol14 = Eq(f(x), C1 - x - sin(2*x)/5 - cos(2*x)/10 + x**2/2 + C2*exp(-x))
sol15 = Eq(f(x), (C1 + x)*sin(x) + (C2 - x**2)*cos(x))
sol16 = Eq(f(x), (C1 + x/16)*sin(2*x) + (C2 - x**2/8)*cos(2*x))
sol17 = Eq(f(x), (C1 + C2*x + x**4/12)*exp(-x))
sol18 = Eq(f(x), (C1 + C2*x + C3*x**2 - x**5/60 + x**3/3)*exp(-x))
sol19 = Eq(f(x), S(7)/4 - 3*x/2 + x**2/2 + C1*exp(-x) + (C2 - x)*exp(-2*x))
sol20 = Eq(f(x), C1*exp(x) + C2*exp(2*x) + (6*x + 5)*exp(-x)/36)
sol21 = Eq(f(x), -S(1)/36 - x/6 + C1*exp(-3*x) + (C2 + x/5)*exp(2*x))
sol22 = Eq(f(x), C1*sin(x) + (C2 - x/2)*cos(x) + exp(-x)/2)
sol23 = Eq(f(x), (C1 + C2*x + C3*x**2 + x**3/6)*exp(x))
sol24 = Eq(f(x), S(1)/2 - cos(2*x)/6 + C1*sin(x) + C2*cos(x))
sol25 = Eq(f(x), C1 + C2*exp(-x) + C3*exp(x) +
(-21*sin(2*x) + 27*cos(2*x) + 130)*exp(2*x)/1560)
sol26 = Eq(f(x),
C1 + (C2 + C3*x - x**2/8)*sin(x) + (C4 + C5*x + x**2/8)*cos(x) + x**2)
sol27 = Eq(f(x), cos(3*x)/16 + C1*cos(x) + (C2 + x/4)*sin(x))
sol28 = Eq(f(x), C1 + x)
sol1s = constant_renumber(sol1, 'C', 1, 3)
sol2s = constant_renumber(sol2, 'C', 1, 3)
sol3s = constant_renumber(sol3, 'C', 1, 2)
sol4s = constant_renumber(sol4, 'C', 1, 2)
sol5s = constant_renumber(sol5, 'C', 1, 2)
sol6s = constant_renumber(sol6, 'C', 1, 2)
sol7s = constant_renumber(sol7, 'C', 1, 2)
sol8s = constant_renumber(sol8, 'C', 1, 2)
sol9s = constant_renumber(sol9, 'C', 1, 2)
sol10s = constant_renumber(sol10, 'C', 1, 2)
sol11s = constant_renumber(sol11, 'C', 1, 2)
sol12s = constant_renumber(sol12, 'C', 1, 2)
sol13s = constant_renumber(sol13, 'C', 1, 4)
sol14s = constant_renumber(sol14, 'C', 1, 2)
sol15s = constant_renumber(sol15, 'C', 1, 2)
sol16s = constant_renumber(sol16, 'C', 1, 2)
sol17s = constant_renumber(sol17, 'C', 1, 2)
sol18s = constant_renumber(sol18, 'C', 1, 3)
sol19s = constant_renumber(sol19, 'C', 1, 2)
sol20s = constant_renumber(sol20, 'C', 1, 2)
sol21s = constant_renumber(sol21, 'C', 1, 2)
sol22s = constant_renumber(sol22, 'C', 1, 2)
sol23s = constant_renumber(sol23, 'C', 1, 3)
sol24s = constant_renumber(sol24, 'C', 1, 2)
sol25s = constant_renumber(sol25, 'C', 1, 3)
sol26s = constant_renumber(sol26, 'C', 1, 5)
sol27s = constant_renumber(sol27, 'C', 1, 2)
assert dsolve(eq1, hint=hint) in (sol1, sol1s)
assert dsolve(eq2, hint=hint) in (sol2, sol2s)
assert dsolve(eq3, hint=hint) in (sol3, sol3s)
assert dsolve(eq4, hint=hint) in (sol4, sol4s)
assert dsolve(eq5, hint=hint) in (sol5, sol5s)
assert dsolve(eq6, hint=hint) in (sol6, sol6s)
assert dsolve(eq7, hint=hint) in (sol7, sol7s)
assert dsolve(eq8, hint=hint) in (sol8, sol8s)
assert dsolve(eq9, hint=hint) in (sol9, sol9s)
assert dsolve(eq10, hint=hint) in (sol10, sol10s)
assert dsolve(eq11, hint=hint) in (sol11, sol11s)
assert dsolve(eq12, hint=hint) in (sol12, sol12s)
assert dsolve(eq13, hint=hint) in (sol13, sol13s)
assert dsolve(eq14, hint=hint) in (sol14, sol14s)
assert dsolve(eq15, hint=hint) in (sol15, sol15s)
assert dsolve(eq16, hint=hint) in (sol16, sol16s)
assert dsolve(eq17, hint=hint) in (sol17, sol17s)
assert dsolve(eq18, hint=hint) in (sol18, sol18s)
assert dsolve(eq19, hint=hint) in (sol19, sol19s)
assert dsolve(eq20, hint=hint) in (sol20, sol20s)
assert dsolve(eq21, hint=hint) in (sol21, sol21s)
assert dsolve(eq22, hint=hint) in (sol22, sol22s)
assert dsolve(eq23, hint=hint) in (sol23, sol23s)
assert dsolve(eq24, hint=hint) in (sol24, sol24s)
assert dsolve(eq25, hint=hint) in (sol25, sol25s)
assert dsolve(eq26, hint=hint) in (sol26, sol26s)
assert dsolve(eq27, hint=hint) in (sol27, sol27s)
assert dsolve(eq28, hint=hint) == sol28
assert checkodesol(eq1, sol1, order=3, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=3, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=2, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=2, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=2, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=2, solve_for_func=False)[0]
assert checkodesol(eq7, sol7, order=2, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=2, solve_for_func=False)[0]
assert checkodesol(eq9, sol9, order=2, solve_for_func=False)[0]
assert checkodesol(eq10, sol10, order=2, solve_for_func=False)[0]
assert checkodesol(eq11, sol11, order=2, solve_for_func=False)[0]
assert checkodesol(eq12, sol12, order=4, solve_for_func=False)[0]
assert checkodesol(eq13, sol13, order=2, solve_for_func=False)[0]
assert checkodesol(eq14, sol14, order=2, solve_for_func=False)[0]
assert checkodesol(eq15, sol15, order=2, solve_for_func=False)[0]
assert checkodesol(eq16, sol16, order=2, solve_for_func=False)[0]
assert checkodesol(eq17, sol17, order=2, solve_for_func=False)[0]
assert checkodesol(eq18, sol18, order=3, solve_for_func=False)[0]
assert checkodesol(eq19, sol19, order=2, solve_for_func=False)[0]
assert checkodesol(eq20, sol20, order=2, solve_for_func=False)[0]
assert checkodesol(eq21, sol21, order=2, solve_for_func=False)[0]
assert checkodesol(eq22, sol22, order=2, solve_for_func=False)[0]
assert checkodesol(eq23, sol23, order=3, solve_for_func=False)[0]
assert checkodesol(eq24, sol24, order=2, solve_for_func=False)[0]
assert checkodesol(eq25, sol25, order=3, solve_for_func=False)[0]
assert checkodesol(eq26, sol26, order=5, solve_for_func=False)[0]
assert checkodesol(eq27, sol27, order=2, solve_for_func=False)[0]
assert checkodesol(eq28, sol28, order=1, solve_for_func=False)[0]
def test_issue_5787():
# This test case is to show the classification of imaginary constants under
# nth_linear_constant_coeff_undetermined_coefficients
eq = Eq(diff(f(x), x), I*f(x) + S(1)/2 - I)
out_hint = 'nth_linear_constant_coeff_undetermined_coefficients'
assert out_hint in classify_ode(eq)
@XFAIL
def test_nth_linear_constant_coeff_undetermined_coefficients_imaginary_exp():
# Equivalent to eq26 in
# test_nth_linear_constant_coeff_undetermined_coefficients above.
# This fails because the algorithm for undetermined coefficients
# doesn't know to multiply exp(I*x) by sufficient x because it is linearly
# dependent on sin(x) and cos(x).
hint = 'nth_linear_constant_coeff_undetermined_coefficients'
eq26a = f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x) - 2*x - exp(I*x)
sol26 = Eq(f(x),
C1 + (C2 + C3*x - x**2/8)*sin(x) + (C4 + C5*x + x**2/8)*cos(x) + x**2)
assert dsolve(eq26a, hint=hint) == sol26
assert checkodesol(eq26a, sol26, order=5, solve_for_func=False)[0]
@slow
def test_nth_linear_constant_coeff_variation_of_parameters():
hint = 'nth_linear_constant_coeff_variation_of_parameters'
g = exp(-x)
f2 = f(x).diff(x, 2)
c = 3*f(x).diff(x, 3) + 5*f2 + f(x).diff(x) - f(x) - x
eq1 = c - x*g
eq2 = c - g
eq3 = f(x).diff(x) - 1
eq4 = f2 + 3*f(x).diff(x) + 2*f(x) - 4
eq5 = f2 + 3*f(x).diff(x) + 2*f(x) - 12*exp(x)
eq6 = f2 - 2*f(x).diff(x) - 8*f(x) - 9*x*exp(x) - 10*exp(-x)
eq7 = f2 + 2*f(x).diff(x) + f(x) - x**2*exp(-x)
eq8 = f2 - 3*f(x).diff(x) + 2*f(x) - x*exp(-x)
eq9 = f(x).diff(x, 3) - 3*f2 + 3*f(x).diff(x) - f(x) - exp(x)
eq10 = f2 + 2*f(x).diff(x) + f(x) - exp(-x)/x
eq11 = f2 + f(x) - 1/sin(x)*1/cos(x)
eq12 = f(x).diff(x, 4) - 1/x
sol1 = Eq(f(x),
-1 - x + (C1 + C2*x - 3*x**2/32 - x**3/24)*exp(-x) + C3*exp(x/3))
sol2 = Eq(f(x), -1 - x + (C1 + C2*x - x**2/8)*exp(-x) + C3*exp(x/3))
sol3 = Eq(f(x), C1 + x)
sol4 = Eq(f(x), 2 + C1*exp(-x) + C2*exp(-2*x))
sol5 = Eq(f(x), 2*exp(x) + C1*exp(-x) + C2*exp(-2*x))
sol6 = Eq(f(x), -x*exp(x) - 2*exp(-x) + C1*exp(-2*x) + C2*exp(4*x))
sol7 = Eq(f(x), (C1 + C2*x + x**4/12)*exp(-x))
sol8 = Eq(f(x), C1*exp(x) + C2*exp(2*x) + (6*x + 5)*exp(-x)/36)
sol9 = Eq(f(x), (C1 + C2*x + C3*x**2 + x**3/6)*exp(x))
sol10 = Eq(f(x), (C1 + x*(C2 + log(x)))*exp(-x))
sol11 = Eq(f(x), cos(x)*(C2 - Integral(1/cos(x), x)) + sin(x)*(C1 +
Integral(1/sin(x), x)))
sol12 = Eq(f(x), C1 + C2*x + x**3*(C3 + log(x)/6) + C4*x**2)
sol1s = constant_renumber(sol1, 'C', 1, 3)
sol2s = constant_renumber(sol2, 'C', 1, 3)
sol3s = constant_renumber(sol3, 'C', 1, 2)
sol4s = constant_renumber(sol4, 'C', 1, 2)
sol5s = constant_renumber(sol5, 'C', 1, 2)
sol6s = constant_renumber(sol6, 'C', 1, 2)
sol7s = constant_renumber(sol7, 'C', 1, 2)
sol8s = constant_renumber(sol8, 'C', 1, 2)
sol9s = constant_renumber(sol9, 'C', 1, 3)
sol10s = constant_renumber(sol10, 'C', 1, 2)
sol11s = constant_renumber(sol11, 'C', 1, 2)
sol12s = constant_renumber(sol12, 'C', 1, 4)
assert dsolve(eq1, hint=hint) in (sol1, sol1s)
assert dsolve(eq2, hint=hint) in (sol2, sol2s)
assert dsolve(eq3, hint=hint) in (sol3, sol3s)
assert dsolve(eq4, hint=hint) in (sol4, sol4s)
assert dsolve(eq5, hint=hint) in (sol5, sol5s)
assert dsolve(eq6, hint=hint) in (sol6, sol6s)
assert dsolve(eq7, hint=hint) in (sol7, sol7s)
assert dsolve(eq8, hint=hint) in (sol8, sol8s)
assert dsolve(eq9, hint=hint) in (sol9, sol9s)
assert dsolve(eq10, hint=hint) in (sol10, sol10s)
assert dsolve(eq11, hint=hint + '_Integral') in (sol11, sol11s)
assert dsolve(eq12, hint=hint) in (sol12, sol12s)
assert checkodesol(eq1, sol1, order=3, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=3, solve_for_func=False)[0]
assert checkodesol(eq3, sol3, order=1, solve_for_func=False)[0]
assert checkodesol(eq4, sol4, order=2, solve_for_func=False)[0]
assert checkodesol(eq5, sol5, order=2, solve_for_func=False)[0]
assert checkodesol(eq6, sol6, order=2, solve_for_func=False)[0]
assert checkodesol(eq7, sol7, order=2, solve_for_func=False)[0]
assert checkodesol(eq8, sol8, order=2, solve_for_func=False)[0]
assert checkodesol(eq9, sol9, order=3, solve_for_func=False)[0]
assert checkodesol(eq10, sol10, order=2, solve_for_func=False)[0]
assert checkodesol(eq12, sol12, order=4, solve_for_func=False)[0]
@slow
def test_nth_linear_constant_coeff_variation_of_parameters_simplify_False():
# solve_variation_of_parameters shouldn't attempt to simplify the
# Wronskian if simplify=False. If wronskian() ever gets good enough
# to simplify the result itself, this test might fail.
hint = 'nth_linear_constant_coeff_variation_of_parameters'
assert dsolve(f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x) -
2*x - exp(I*x), f(x), hint + "_Integral", simplify=False) != \
dsolve(f(x).diff(x, 5) + 2*f(x).diff(x, 3) + f(x).diff(x) -
2*x - exp(I*x), f(x), hint + "_Integral", simplify=True)
def test_Liouville_ODE():
hint = 'Liouville'
# The first part here used to be test_ODE_1() from test_solvers.py
eq1 = diff(f(x), x)/x + diff(f(x), x, x)/2 - diff(f(x), x)**2/2
eq1a = diff(x*exp(-f(x)), x, x)
# compare to test_unexpanded_Liouville_ODE() below
eq2 = (eq1*exp(-f(x))/exp(f(x))).expand()
eq3 = diff(f(x), x, x) + 1/f(x)*(diff(f(x), x))**2 + 1/x*diff(f(x), x)
eq4 = x*diff(f(x), x, x) + x/f(x)*diff(f(x), x)**2 + x*diff(f(x), x)
eq5 = Eq((x*exp(f(x))).diff(x, x), 0)
sol1 = Eq(f(x), log(x/(C1 + C2*x)))
sol1a = Eq(C1 + C2/x - exp(-f(x)), 0)
sol2 = sol1
sol3 = set(
[Eq(f(x), -sqrt(C1 + C2*log(x))),
Eq(f(x), sqrt(C1 + C2*log(x)))])
sol4 = set([Eq(f(x), sqrt(C1 + C2*exp(x))*exp(-x/2)),
Eq(f(x), -sqrt(C1 + C2*exp(x))*exp(-x/2))])
sol5 = Eq(f(x), log(C1 + C2/x))
sol1s = constant_renumber(sol1, 'C', 1, 2)
sol2s = constant_renumber(sol2, 'C', 1, 2)
sol3s = constant_renumber(sol3, 'C', 1, 2)
sol4s = constant_renumber(sol4, 'C', 1, 2)
sol5s = constant_renumber(sol5, 'C', 1, 2)
assert dsolve(eq1, hint=hint) in (sol1, sol1s)
assert dsolve(eq1a, hint=hint) in (sol1, sol1s)
assert dsolve(eq2, hint=hint) in (sol2, sol2s)
assert set(dsolve(eq3, hint=hint)) in (sol3, sol3s)
assert set(dsolve(eq4, hint=hint)) in (sol4, sol4s)
assert dsolve(eq5, hint=hint) in (sol5, sol5s)
assert checkodesol(eq1, sol1, order=2, solve_for_func=False)[0]
assert checkodesol(eq1a, sol1a, order=2, solve_for_func=False)[0]
assert checkodesol(eq2, sol2, order=2, solve_for_func=False)[0]
assert all(i[0] for i in checkodesol(eq3, sol3, order=2,
solve_for_func=False))
assert all(i[0] for i in checkodesol(eq4, sol4, order=2,
solve_for_func=False))
assert checkodesol(eq5, sol5, order=2, solve_for_func=False)[0]
not_Liouville1 = classify_ode(diff(f(x), x)/x + f(x)*diff(f(x), x, x)/2 -
diff(f(x), x)**2/2, f(x))
not_Liouville2 = classify_ode(diff(f(x), x)/x + diff(f(x), x, x)/2 -
x*diff(f(x), x)**2/2, f(x))
assert hint not in not_Liouville1
assert hint not in not_Liouville2
assert hint + '_Integral' not in not_Liouville1
assert hint + '_Integral' not in not_Liouville2
def test_unexpanded_Liouville_ODE():
# This is the same as eq1 from test_Liouville_ODE() above.
eq1 = diff(f(x), x)/x + diff(f(x), x, x)/2 - diff(f(x), x)**2/2
eq2 = eq1*exp(-f(x))/exp(f(x))
sol2 = Eq(f(x), log(x/(C1 + C2*x)))
sol2s = constant_renumber(sol2, 'C', 1, 2)
assert dsolve(eq2) in (sol2, sol2s)
assert checkodesol(eq2, sol2, order=2, solve_for_func=False)[0]
def test_issue_4785():
from sympy.abc import A
eq = x + A*(x + diff(f(x), x) + f(x)) + diff(f(x), x) + f(x) + 2
assert classify_ode(eq, f(x)) == ('1st_linear', 'almost_linear',
'1st_power_series', 'lie_group',
'nth_linear_constant_coeff_undetermined_coefficients',
'nth_linear_constant_coeff_variation_of_parameters',
'1st_linear_Integral', 'almost_linear_Integral',
'nth_linear_constant_coeff_variation_of_parameters_Integral')
# issue 4864
eq = (x**2 + f(x)**2)*f(x).diff(x) - 2*x*f(x)
assert classify_ode(eq, f(x)) == ('1st_exact',
'1st_homogeneous_coeff_best',
'1st_homogeneous_coeff_subs_indep_div_dep',
'1st_homogeneous_coeff_subs_dep_div_indep',
'1st_power_series',
'lie_group', '1st_exact_Integral',
'1st_homogeneous_coeff_subs_indep_div_dep_Integral',
'1st_homogeneous_coeff_subs_dep_div_indep_Integral')
def test_issue_4825():
raises(ValueError, lambda: dsolve(f(x, y).diff(x) - y*f(x, y), f(x)))
assert classify_ode(f(x, y).diff(x) - y*f(x, y), f(x), dict=True) == \
{'default': None, 'order': 0}
# See also issue 3793, test Z13.
raises(ValueError, lambda: dsolve(f(x).diff(x), f(y)))
assert classify_ode(f(x).diff(x), f(y), dict=True) == \
{'default': None, 'order': 0}
def test_constant_renumber_order_issue_5308():
from sympy.utilities.iterables import variations
assert constant_renumber(C1*x + C2*y, "C", 1, 2) == \
constant_renumber(C1*y + C2*x, "C", 1, 2) == \
C1*x + C2*y
e = C1*(C2 + x)*(C3 + y)
for a, b, c in variations([C1, C2, C3], 3):
assert constant_renumber(a*(b + x)*(c + y), "C", 1, 3) == e
def test_issue_5770():
k = Symbol("k", real=True)
t = Symbol('t')
w = Function('w')
sol = dsolve(w(t).diff(t, 6) - k**6*w(t), w(t))
assert len([s for s in sol.free_symbols if s.name.startswith('C')]) == 6
assert constantsimp((C1*cos(x) + C2*cos(x))*exp(x), set([C1, C2])) == \
C1*cos(x)*exp(x)
assert constantsimp(C1*cos(x) + C2*cos(x) + C3*sin(x), set([C1, C2, C3])) == \
C1*cos(x) + C3*sin(x)
assert constantsimp(exp(C1 + x), set([C1])) == C1*exp(x)
assert constantsimp(x + C1 + y, set([C1, y])) == C1 + x
assert constantsimp(x + C1 + Integral(x, (x, 1, 2)), set([C1])) == C1 + x
def test_issue_5112_5430():
assert homogeneous_order(-log(x) + acosh(x), x) is None
assert homogeneous_order(y - log(x), x, y) is None
def test_nth_order_linear_euler_eq_homogeneous():
x, t, a, b, c = symbols('x t a b c')
y = Function('y')
our_hint = "nth_linear_euler_eq_homogeneous"
eq = diff(f(t), t, 4)*t**4 - 13*diff(f(t), t, 2)*t**2 + 36*f(t)
assert our_hint in classify_ode(eq)
eq = a*y(t) + b*t*diff(y(t), t) + c*t**2*diff(y(t), t, 2)
assert our_hint in classify_ode(eq)
eq = Eq(-3*diff(f(x), x)*x + 2*x**2*diff(f(x), x, x), 0)
sol = C1 + C2*x**Rational(5, 2)
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(3*f(x) - 5*diff(f(x), x)*x + 2*x**2*diff(f(x), x, x), 0)
sol = C1*sqrt(x) + C2*x**3
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(4*f(x) + 5*diff(f(x), x)*x + x**2*diff(f(x), x, x), 0)
sol = (C1 + C2*log(x))/x**2
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(6*f(x) - 6*diff(f(x), x)*x + 1*x**2*diff(f(x), x, x) + x**3*diff(f(x), x, x, x), 0)
sol = dsolve(eq, f(x), hint=our_hint)
sol = C1/x**2 + C2*x + C3*x**3
sols = constant_renumber(sol, 'C', 1, 4)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(-125*f(x) + 61*diff(f(x), x)*x - 12*x**2*diff(f(x), x, x) + x**3*diff(f(x), x, x, x), 0)
sol = x**5*(C1 + C2*log(x) + C3*log(x)**2)
sols = [sol, constant_renumber(sol, 'C', 1, 4)]
sols += [sols[-1].expand()]
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in sols
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = t**2*diff(y(t), t, 2) + t*diff(y(t), t) - 9*y(t)
sol = C1*t**3 + C2*t**-3
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, y(t), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = sin(x)*x**2*f(x).diff(x, 2) + sin(x)*x*f(x).diff(x) + sin(x)*f(x)
sol = C1*sin(log(x)) + C2*cos(log(x))
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
def test_nth_order_linear_euler_eq_nonhomogeneous_undetermined_coefficients():
x, t = symbols('x t')
a, b, c, d = symbols('a b c d', integer=True)
our_hint = "nth_linear_euler_eq_nonhomogeneous_undetermined_coefficients"
eq = x**4*diff(f(x), x, 4) - 13*x**2*diff(f(x), x, 2) + 36*f(x) + x
assert our_hint in classify_ode(eq, f(x))
eq = a*x**2*diff(f(x), x, 2) + b*x*diff(f(x), x) + c*f(x) + d*log(x)
assert our_hint in classify_ode(eq, f(x))
eq = Eq(x**2*diff(f(x), x, x) + x*diff(f(x), x), 1)
sol = C1 + C2*log(x) + log(x)**2/2
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq, f(x))
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(x**2*diff(f(x), x, x) - 2*x*diff(f(x), x) + 2*f(x), x**3)
sol = x*(C1 + C2*x + Rational(1, 2)*x**2)
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq, f(x))
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(x**2*diff(f(x), x, x) - x*diff(f(x), x) - 3*f(x), log(x)/x)
sol = C1/x + C2*x**3 - Rational(1, 16)*log(x)/x - Rational(1, 8)*log(x)**2/x
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq, f(x))
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(x**2*diff(f(x), x, x) + 3*x*diff(f(x), x) - 8*f(x), log(x)**3 - log(x))
sol = C1/x**4 + C2*x**2 - Rational(1,8)*log(x)**3 - Rational(3,32)*log(x)**2 - Rational(1,64)*log(x) - Rational(7, 256)
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(x**3*diff(f(x), x, x, x) - 3*x**2*diff(f(x), x, x) + 6*x*diff(f(x), x) - 6*f(x), log(x))
sol = C1*x + C2*x**2 + C3*x**3 - Rational(1, 6)*log(x) - Rational(11, 36)
sols = constant_renumber(sol, 'C', 1, 3)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
def test_nth_order_linear_euler_eq_nonhomogeneous_variation_of_parameters():
x, t = symbols('x, t')
a, b, c, d = symbols('a, b, c, d', integer=True)
our_hint = "nth_linear_euler_eq_nonhomogeneous_variation_of_parameters"
eq = Eq(x**2*diff(f(x),x,2) - 8*x*diff(f(x),x) + 12*f(x), x**2)
assert our_hint in classify_ode(eq, f(x))
eq = Eq(a*x**3*diff(f(x),x,3) + b*x**2*diff(f(x),x,2) + c*x*diff(f(x),x) + d*f(x), x*log(x))
assert our_hint in classify_ode(eq, f(x))
eq = Eq(x**2*Derivative(f(x), x, x) - 2*x*Derivative(f(x), x) + 2*f(x), x**4)
sol = C1*x + C2*x**2 + x**4/6
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(3*x**2*diff(f(x), x, x) + 6*x*diff(f(x), x) - 6*f(x), x**3*exp(x))
sol = C1/x**2 + C2*x + x*exp(x)/3 - 4*exp(x)/3 + 8*exp(x)/(3*x) - 8*exp(x)/(3*x**2)
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = Eq(x**2*Derivative(f(x), x, x) - 2*x*Derivative(f(x), x) + 2*f(x), x**4*exp(x))
sol = C1*x + C2*x**2 + x**2*exp(x) - 2*x*exp(x)
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs.expand() in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = x**2*Derivative(f(x), x, x) - 2*x*Derivative(f(x), x) + 2*f(x) - log(x)
sol = C1*x + C2*x**2 + log(x)/2 + S(3)/4
sols = constant_renumber(sol, 'C', 1, 2)
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint).rhs in (sol, sols)
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
eq = -exp(x) + (x*Derivative(f(x), (x, 2)) + Derivative(f(x), x))/x
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert our_hint in classify_ode(eq)
assert dsolve(eq, f(x), hint=our_hint) == sol
assert checkodesol(eq, sol, order=2, solve_for_func=False)[0]
def test_issue_5095():
f = Function('f')
raises(ValueError, lambda: dsolve(f(x).diff(x)**2, f(x), 'separable'))
raises(ValueError, lambda: dsolve(f(x).diff(x)**2, f(x), 'fdsjf'))
def test_almost_linear():
from sympy import Ei
A = Symbol('A', positive=True)
our_hint = 'almost_linear'
f = Function('f')
d = f(x).diff(x)
eq = x**2*f(x)**2*d + f(x)**3 + 1
sol = dsolve(eq, f(x), hint = 'almost_linear')
assert sol[0].rhs == (C1*exp(3/x) - 1)**(S(1)/3)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
eq = x*f(x)*d + 2*x*f(x)**2 + 1
sol = dsolve(eq, f(x), hint = 'almost_linear')
assert sol[0].rhs == -sqrt(C1 - 2*Ei(4*x))*exp(-2*x)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
eq = x*d + x*f(x) + 1
sol = dsolve(eq, f(x), hint = 'almost_linear')
assert sol.rhs == (C1 - Ei(x))*exp(-x)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
assert our_hint in classify_ode(eq, f(x))
eq = x*exp(f(x))*d + exp(f(x)) + 3*x
sol = dsolve(eq, f(x), hint = 'almost_linear')
assert sol.rhs == log(C1/x - 3*x/2)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
eq = x + A*(x + diff(f(x), x) + f(x)) + diff(f(x), x) + f(x) + 2
sol = dsolve(eq, f(x), hint = 'almost_linear')
assert sol.rhs == (C1 + Piecewise(
(x, Eq(A + 1, 0)), ((-A*x + A - x - 1)*exp(x)/(A + 1), True)))*exp(-x)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_exact_enhancement():
f = Function('f')(x)
df = Derivative(f, x)
eq = f/x**2 + ((f*x - 1)/x)*df
sol = dsolve(eq, f)
assert sol == [Eq(f, (i*sqrt(C1*x**2 + 1) + 1)/x) for i in (-1, 1)]
eq = (x*f - 1) + df*(x**2 - x*f)
rhs = [sol.rhs for sol in dsolve(eq, f)]
assert rhs[0] == x - sqrt(C1 + x**2 - 2*log(x))
assert rhs[1] == x + sqrt(C1 + x**2 - 2*log(x))
eq = (x + 2)*sin(f) + df*x*cos(f)
rhs = [sol.rhs for sol in dsolve(eq, f)]
assert rhs == [
-asin(C1*exp(-x)/x**2) + pi,
asin(C1*exp(-x)/x**2)]
def test_separable_reduced():
f = Function('f')
x = Symbol('x')
df = f(x).diff(x)
eq = (x / f(x))*df + tan(x**2*f(x) / (x**2*f(x) - 1))
assert classify_ode(eq) == ('separable_reduced', 'lie_group',
'separable_reduced_Integral')
eq = x* df + f(x)* (1 / (x**2*f(x) - 1))
assert classify_ode(eq) == ('separable_reduced', 'lie_group',
'separable_reduced_Integral')
sol = dsolve(eq, hint = 'separable_reduced', simplify=False)
assert sol.lhs == log(x**2*f(x))/3 + log(x**2*f(x) - S(3)/2)/6
assert sol.rhs == C1 + log(x)
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
eq = f(x).diff(x) + (f(x) / (x**4*f(x) - x))
assert classify_ode(eq) == ('separable_reduced', 'lie_group',
'separable_reduced_Integral')
sol = dsolve(eq, hint = 'separable_reduced')
assert len(sol) == 4
eq = x*df + f(x)*(x**2*f(x))
sol = dsolve(eq, hint = 'separable_reduced', simplify=False)
assert sol == Eq(log(x**2*f(x))/2 - log(x**2*f(x) - 2)/2, C1 + log(x))
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_homogeneous_function():
f = Function('f')
eq1 = tan(x + f(x))
eq2 = sin((3*x)/(4*f(x)))
eq3 = cos(3*x/4*f(x))
eq4 = log((3*x + 4*f(x))/(5*f(x) + 7*x))
eq5 = exp((2*x**2)/(3*f(x)**2))
eq6 = log((3*x + 4*f(x))/(5*f(x) + 7*x) + exp((2*x**2)/(3*f(x)**2)))
eq7 = sin((3*x)/(5*f(x) + x**2))
assert homogeneous_order(eq1, x, f(x)) == None
assert homogeneous_order(eq2, x, f(x)) == 0
assert homogeneous_order(eq3, x, f(x)) == None
assert homogeneous_order(eq4, x, f(x)) == 0
assert homogeneous_order(eq5, x, f(x)) == 0
assert homogeneous_order(eq6, x, f(x)) == 0
assert homogeneous_order(eq7, x, f(x)) == None
def test_linear_coeff_match():
from sympy.solvers.ode import _linear_coeff_match
n, d = z*(2*x + 3*f(x) + 5), z*(7*x + 9*f(x) + 11)
rat = n/d
eq1 = sin(rat) + cos(rat.expand())
eq2 = rat
eq3 = log(sin(rat))
ans = (4, -S(13)/3)
assert _linear_coeff_match(eq1, f(x)) == ans
assert _linear_coeff_match(eq2, f(x)) == ans
assert _linear_coeff_match(eq3, f(x)) == ans
# no c
eq4 = (3*x)/f(x)
# not x and f(x)
eq5 = (3*x + 2)/x
# denom will be zero
eq6 = (3*x + 2*f(x) + 1)/(3*x + 2*f(x) + 5)
# not rational coefficient
eq7 = (3*x + 2*f(x) + sqrt(2))/(3*x + 2*f(x) + 5)
assert _linear_coeff_match(eq4, f(x)) is None
assert _linear_coeff_match(eq5, f(x)) is None
assert _linear_coeff_match(eq6, f(x)) is None
assert _linear_coeff_match(eq7, f(x)) is None
def test_linear_coefficients():
f = Function('f')
sol = Eq(f(x), C1/(x**2 + 6*x + 9) - S(3)/2)
eq = f(x).diff(x) + (3 + 2*f(x))/(x + 3)
assert dsolve(eq, hint='linear_coefficients') == sol
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_constantsimp_take_problem():
c = exp(C1) + 2
assert len(Poly(constantsimp(exp(C1) + c + c*x, [C1])).gens) == 2
def test_issue_6879():
f = Function('f')
eq = Eq(Derivative(f(x), x, 2) - 2*Derivative(f(x), x) + f(x), sin(x))
sol = (C1 + C2*x)*exp(x) + cos(x)/2
assert dsolve(eq).rhs == sol
assert checkodesol(eq, sol, order=1, solve_for_func=False)[0]
def test_issue_6989():
f = Function('f')
k = Symbol('k')
assert dsolve(f(x).diff(x) - x*exp(-k*x), f(x)) == Eq(f(x),
C1 + Piecewise(
((-k*x - 1)*exp(-k*x)/k**2, Ne(k**2, 0)),
(x**2/2, True)
))
eq = -f(x).diff(x) + x*exp(-k*x)
sol = dsolve(eq, f(x))
actual_sol = Eq(f(x), C1 + Piecewise(
((-k*x - 1)*exp(-k*x)/k**2, Ne(k**2, 0)),
(+x**2/2, True)
))
errstr = str(eq) + ' : ' + str(sol) + ' == ' + str(actual_sol)
assert sol == actual_sol, errstr
def test_heuristic1():
y, a, b, c, a4, a3, a2, a1, a0 = symbols("y a b c a4 a3 a2 a1 a0")
y = Symbol('y')
f = Function('f')
xi = Function('xi')
eta = Function('eta')
df = f(x).diff(x)
eq = Eq(df, x**2*f(x))
eq1 = f(x).diff(x) + a*f(x) - c*exp(b*x)
eq2 = f(x).diff(x) + 2*x*f(x) - x*exp(-x**2)
eq3 = (1 + 2*x)*df + 2 - 4*exp(-f(x))
eq4 = f(x).diff(x) - (a4*x**4 + a3*x**3 + a2*x**2 + a1*x + a0)**(S(-1)/2)
eq5 = x**2*df - f(x) + x**2*exp(x - (1/x))
eqlist = [eq, eq1, eq2, eq3, eq4, eq5]
i = infinitesimals(eq, hint='abaco1_simple')
assert i == [{eta(x, f(x)): exp(x**3/3), xi(x, f(x)): 0},
{eta(x, f(x)): f(x), xi(x, f(x)): 0},
{eta(x, f(x)): 0, xi(x, f(x)): x**(-2)}]
i1 = infinitesimals(eq1, hint='abaco1_simple')
assert i1 == [{eta(x, f(x)): exp(-a*x), xi(x, f(x)): 0}]
i2 = infinitesimals(eq2, hint='abaco1_simple')
assert i2 == [{eta(x, f(x)): exp(-x**2), xi(x, f(x)): 0}]
i3 = infinitesimals(eq3, hint='abaco1_simple')
assert i3 == [{eta(x, f(x)): 0, xi(x, f(x)): 2*x + 1},
{eta(x, f(x)): 0, xi(x, f(x)): 1/(exp(f(x)) - 2)}]
i4 = infinitesimals(eq4, hint='abaco1_simple')
assert i4 == [{eta(x, f(x)): 1, xi(x, f(x)): 0},
{eta(x, f(x)): 0,
xi(x, f(x)): sqrt(a0 + a1*x + a2*x**2 + a3*x**3 + a4*x**4)}]
i5 = infinitesimals(eq5, hint='abaco1_simple')
assert i5 == [{xi(x, f(x)): 0, eta(x, f(x)): exp(-1/x)}]
ilist = [i, i1, i2, i3, i4, i5]
for eq, i in (zip(eqlist, ilist)):
check = checkinfsol(eq, i)
assert check[0]
def test_issue_6247():
eq = x**2*f(x)**2 + x*Derivative(f(x), x)
sol = dsolve(eq, hint = 'separable_reduced')
assert checkodesol(eq, sol, order=1)[0]
eq = f(x).diff(x, x) + 4*f(x)
sol = dsolve(eq, f(x), simplify=False)
assert sol == Eq(f(x), C1*sin(2*x) + C2*cos(2*x))
def test_heuristic2():
y = Symbol('y')
xi = Function('xi')
eta = Function('eta')
df = f(x).diff(x)
# This ODE can be solved by the Lie Group method, when there are
# better assumptions
eq = df - (f(x)/x)*(x*log(x**2/f(x)) + 2)
i = infinitesimals(eq, hint='abaco1_product')
assert i == [{eta(x, f(x)): f(x)*exp(-x), xi(x, f(x)): 0}]
assert checkinfsol(eq, i)[0]
@slow
def test_heuristic3():
y = Symbol('y')
xi = Function('xi')
eta = Function('eta')
a, b = symbols("a b")
df = f(x).diff(x)
eq = x**2*df + x*f(x) + f(x)**2 + x**2
i = infinitesimals(eq, hint='bivariate')
assert i == [{eta(x, f(x)): f(x), xi(x, f(x)): x}]
assert checkinfsol(eq, i)[0]
eq = x**2*(-f(x)**2 + df)- a*x**2*f(x) + 2 - a*x
i = infinitesimals(eq, hint='bivariate')
assert checkinfsol(eq, i)[0]
def test_heuristic_4():
y, a = symbols("y a")
xi = Function('xi')
eta = Function('eta')
eq = x*(f(x).diff(x)) + 1 - f(x)**2
i = infinitesimals(eq, hint='chi')
assert checkinfsol(eq, i)[0]
def test_heuristic_function_sum():
xi = Function('xi')
eta = Function('eta')
eq = f(x).diff(x) - (3*(1 + x**2/f(x)**2)*atan(f(x)/x) + (1 - 2*f(x))/x +
(1 - 3*f(x))*(x/f(x)**2))
i = infinitesimals(eq, hint='function_sum')
assert i == [{eta(x, f(x)): f(x)**(-2) + x**(-2), xi(x, f(x)): 0}]
assert checkinfsol(eq, i)[0]
def test_heuristic_abaco2_similar():
xi = Function('xi')
eta = Function('eta')
F = Function('F')
a, b = symbols("a b")
eq = f(x).diff(x) - F(a*x + b*f(x))
i = infinitesimals(eq, hint='abaco2_similar')
assert i == [{eta(x, f(x)): -a/b, xi(x, f(x)): 1}]
assert checkinfsol(eq, i)[0]
eq = f(x).diff(x) - (f(x)**2 / (sin(f(x) - x) - x**2 + 2*x*f(x)))
i = infinitesimals(eq, hint='abaco2_similar')
assert i == [{eta(x, f(x)): f(x)**2, xi(x, f(x)): f(x)**2}]
assert checkinfsol(eq, i)[0]
def test_heuristic_abaco2_unique_unknown():
xi = Function('xi')
eta = Function('eta')
F = Function('F')
a, b = symbols("a b")
x = Symbol("x", positive=True)
eq = f(x).diff(x) - x**(a - 1)*(f(x)**(1 - b))*F(x**a/a + f(x)**b/b)
i = infinitesimals(eq, hint='abaco2_unique_unknown')
assert i == [{eta(x, f(x)): -f(x)*f(x)**(-b), xi(x, f(x)): x*x**(-a)}]
assert checkinfsol(eq, i)[0]
eq = f(x).diff(x) + tan(F(x**2 + f(x)**2) + atan(x/f(x)))
i = infinitesimals(eq, hint='abaco2_unique_unknown')
assert i == [{eta(x, f(x)): x, xi(x, f(x)): -f(x)}]
assert checkinfsol(eq, i)[0]
eq = (x*f(x).diff(x) + f(x) + 2*x)**2 -4*x*f(x) -4*x**2 -4*a
i = infinitesimals(eq, hint='abaco2_unique_unknown')
assert checkinfsol(eq, i)[0]
def test_heuristic_linear():
xi = Function('xi')
eta = Function('eta')
F = Function('F')
a, b, m, n = symbols("a b m n")
eq = x**(n*(m + 1) - m)*(f(x).diff(x)) - a*f(x)**n -b*x**(n*(m + 1))
i = infinitesimals(eq, hint='linear')
assert checkinfsol(eq, i)[0]
@XFAIL
def test_kamke():
a, b, alpha, c = symbols("a b alpha c")
eq = x**2*(a*f(x)**2+(f(x).diff(x))) + b*x**alpha + c
i = infinitesimals(eq, hint='sum_function')
assert checkinfsol(eq, i)[0]
def test_series():
C1 = Symbol("C1")
eq = f(x).diff(x) - f(x)
assert dsolve(eq, hint='1st_power_series') == Eq(f(x),
C1 + C1*x + C1*x**2/2 + C1*x**3/6 + C1*x**4/24 +
C1*x**5/120 + O(x**6))
eq = f(x).diff(x) - x*f(x)
assert dsolve(eq, hint='1st_power_series') == Eq(f(x),
C1*x**4/8 + C1*x**2/2 + C1 + O(x**6))
eq = f(x).diff(x) - sin(x*f(x))
sol = Eq(f(x), (x - 2)**2*(1+ sin(4))*cos(4) + (x - 2)*sin(4) + 2 + O(x**3))
assert dsolve(eq, hint='1st_power_series', ics={f(2): 2}, n=3) == sol
@slow
def test_lie_group():
C1 = Symbol("C1")
x = Symbol("x") # assuming x is real generates an error!
a, b, c = symbols("a b c")
eq = f(x).diff(x)**2
sol = dsolve(eq, f(x), hint='lie_group')
assert checkodesol(eq, sol)[0]
eq = Eq(f(x).diff(x), x**2*f(x))
sol = dsolve(eq, f(x), hint='lie_group')
assert sol == Eq(f(x), C1*exp(x**3)**(1/3))
assert checkodesol(eq, sol)[0]
eq = f(x).diff(x) + a*f(x) - c*exp(b*x)
sol = dsolve(eq, f(x), hint='lie_group')
assert checkodesol(eq, sol)[0]
eq = f(x).diff(x) + 2*x*f(x) - x*exp(-x**2)
sol = dsolve(eq, f(x), hint='lie_group')
actual_sol = Eq(f(x), (C1 + x**2/2)*exp(-x**2))
errstr = str(eq)+' : '+str(sol)+' == '+str(actual_sol)
assert sol == actual_sol, errstr
assert checkodesol(eq, sol)[0]
eq = (1 + 2*x)*(f(x).diff(x)) + 2 - 4*exp(-f(x))
sol = dsolve(eq, f(x), hint='lie_group')
assert sol == Eq(f(x), log(C1/(2*x + 1) + 2))
assert checkodesol(eq, sol)[0]
eq = x**2*(f(x).diff(x)) - f(x) + x**2*exp(x - (1/x))
sol = dsolve(eq, f(x), hint='lie_group')
assert checkodesol(eq, sol)[0]
eq = x**2*f(x)**2 + x*Derivative(f(x), x)
sol = dsolve(eq, f(x), hint='lie_group')
assert sol == Eq(f(x), 2/(C1 + x**2))
assert checkodesol(eq, sol)[0]
@XFAIL
def test_lie_group_issue15219():
eqn = exp(f(x).diff(x)-f(x))
assert 'lie_group' not in classify_ode(eqn, f(x))
def test_user_infinitesimals():
C2 = Symbol("C2")
x = Symbol("x") # assuming x is real generates an error
eq = x*(f(x).diff(x)) + 1 - f(x)**2
sol = dsolve(eq, hint='lie_group', xi=sqrt(f(x) - 1)/sqrt(f(x) + 1),
eta=0)
actual_sol = Eq(f(x), (C1 + x**2)/(C1 - x**2))
errstr = str(eq)+' : '+str(sol)+' == '+str(actual_sol)
assert sol == actual_sol, errstr
raises(ValueError, lambda: dsolve(eq, hint='lie_group', xi=0, eta=f(x)))
def test_issue_7081():
eq = x*(f(x).diff(x)) + 1 - f(x)**2
assert dsolve(eq) == Eq(f(x), -1/(-C1 + x**2)*(C1 + x**2))
def test_2nd_power_series_ordinary():
C1, C2 = symbols("C1 C2")
eq = f(x).diff(x, 2) - x*f(x)
assert classify_ode(eq) == ('2nd_power_series_ordinary',)
assert dsolve(eq) == Eq(f(x),
C2*(x**3/6 + 1) + C1*x*(x**3/12 + 1) + O(x**6))
assert dsolve(eq, x0=-2) == Eq(f(x),
C2*((x + 2)**4/6 + (x + 2)**3/6 - (x + 2)**2 + 1)
+ C1*(x + (x + 2)**4/12 - (x + 2)**3/3 + S(2))
+ O(x**6))
assert dsolve(eq, n=2) == Eq(f(x), C2*x + C1 + O(x**2))
eq = (1 + x**2)*(f(x).diff(x, 2)) + 2*x*(f(x).diff(x)) -2*f(x)
assert classify_ode(eq) == ('2nd_power_series_ordinary',)
assert dsolve(eq) == Eq(f(x), C2*(-x**4/3 + x**2 + 1) + C1*x
+ O(x**6))
eq = f(x).diff(x, 2) + x*(f(x).diff(x)) + f(x)
assert classify_ode(eq) == ('2nd_power_series_ordinary',)
assert dsolve(eq) == Eq(f(x), C2*(
x**4/8 - x**2/2 + 1) + C1*x*(-x**2/3 + 1) + O(x**6))
eq = f(x).diff(x, 2) + f(x).diff(x) - x*f(x)
assert classify_ode(eq) == ('2nd_power_series_ordinary',)
assert dsolve(eq) == Eq(f(x), C2*(
-x**4/24 + x**3/6 + 1) + C1*x*(x**3/24 + x**2/6 - x/2
+ 1) + O(x**6))
eq = f(x).diff(x, 2) + x*f(x)
assert classify_ode(eq) == ('2nd_power_series_ordinary',)
assert dsolve(eq, n=7) == Eq(f(x), C2*(
x**6/180 - x**3/6 + 1) + C1*x*(-x**3/12 + 1) + O(x**7))
def test_2nd_power_series_regular():
C1, C2 = symbols("C1 C2")
eq = x**2*(f(x).diff(x, 2)) - 3*x*(f(x).diff(x)) + (4*x + 4)*f(x)
assert dsolve(eq) == Eq(f(x), C1*x**2*(-16*x**3/9 +
4*x**2 - 4*x + 1) + O(x**6))
eq = 4*x**2*(f(x).diff(x, 2)) -8*x**2*(f(x).diff(x)) + (4*x**2 +
1)*f(x)
assert dsolve(eq) == Eq(f(x), C1*sqrt(x)*(
x**4/24 + x**3/6 + x**2/2 + x + 1) + O(x**6))
eq = x**2*(f(x).diff(x, 2)) - x**2*(f(x).diff(x)) + (
x**2 - 2)*f(x)
assert dsolve(eq) == Eq(f(x), C1*(-x**6/720 - 3*x**5/80 - x**4/8 +
x**2/2 + x/2 + 1)/x + C2*x**2*(-x**3/60 + x**2/20 + x/2 + 1)
+ O(x**6))
eq = x**2*(f(x).diff(x, 2)) + x*(f(x).diff(x)) + (x**2 - S(1)/4)*f(x)
assert dsolve(eq) == Eq(f(x), C1*(x**4/24 - x**2/2 + 1)/sqrt(x) +
C2*sqrt(x)*(x**4/120 - x**2/6 + 1) + O(x**6))
eq = x*(f(x).diff(x, 2)) - f(x).diff(x) + 4*x**3*f(x)
assert dsolve(eq) == Eq(f(x), C2*(-x**4/2 + 1) + C1*x**2 + O(x**6))
def test_issue_7093():
x = Symbol("x") # assuming x is real leads to an error
sol = [Eq(f(x), C1 - 2*x*sqrt(x**3)/5),
Eq(f(x), C1 + 2*x*sqrt(x**3)/5)]
eq = Derivative(f(x), x)**2 - x**3
assert (set(dsolve(eq)) == set(sol) and
checkodesol(eq, sol) == [(True, 0)] * 2)
def test_dsolve_linsystem_symbol():
eps = Symbol('epsilon', positive=True)
eq1 = (Eq(diff(f(x), x), -eps*g(x)), Eq(diff(g(x), x), eps*f(x)))
sol1 = [Eq(f(x), -C1*eps*cos(eps*x) - C2*eps*sin(eps*x)),
Eq(g(x), -C1*eps*sin(eps*x) + C2*eps*cos(eps*x))]
assert checksysodesol(eq1, sol1) == (True, [0, 0])
def test_C1_function_9239():
t = Symbol('t')
C1 = Function('C1')
C2 = Function('C2')
C3 = Symbol('C3')
C4 = Symbol('C4')
eq = (Eq(diff(C1(t), t), 9*C2(t)), Eq(diff(C2(t), t), 12*C1(t)))
sol = [Eq(C1(t), 9*C3*exp(6*sqrt(3)*t) + 9*C4*exp(-6*sqrt(3)*t)),
Eq(C2(t), 6*sqrt(3)*C3*exp(6*sqrt(3)*t) - 6*sqrt(3)*C4*exp(-6*sqrt(3)*t))]
assert checksysodesol(eq, sol) == (True, [0, 0])
def test_issue_15056():
t = Symbol('t')
C3 = Symbol('C3')
assert get_numbered_constants(Symbol('C1') * Function('C2')(t)) == C3
def test_issue_10379():
t,y = symbols('t,y')
sol = dsolve(f(t).diff(t)-(1-51.05*y*f(t)), rational=False)
ans = Eq(f(t), (0.019588638589618*exp(y*(C1 - 51.05*t)) + 0.019588638589618)/y)
assert str(sol) == str(ans)
def test_issue_10867():
x = Symbol('x')
v = Eq(g(x).diff(x).diff(x), (x-2)**2 + (x-3)**3)
ans = Eq(g(x), C1 + C2*x + x**5/20 - 2*x**4/3 + 23*x**3/6 - 23*x**2/2)
assert dsolve(v, g(x)) == ans
def test_issue_11290():
eq = cos(f(x)) - (x*sin(f(x)) - f(x)**2)*f(x).diff(x)
sol_1 = dsolve(eq, f(x), simplify=False, hint='1st_exact_Integral')
sol_0 = dsolve(eq, f(x), simplify=False, hint='1st_exact')
assert sol_1.dummy_eq(Eq(Subs(
Integral(u**2 - x*sin(u) - Integral(-sin(u), x), u) +
Integral(cos(u), x), u, f(x)), C1))
assert sol_1.doit() == sol_0
def test_issue_14395():
sol = Eq(f(x), (C1 - x/3 + sin(2*x)/3)*sin(3*x) + (C2 + log(cos(x))
- 2*log(cos(x)**2)/3 + 2*cos(x)**2/3)*cos(3*x))
assert dsolve(Derivative(f(x), x, x) + 9*f(x) - sec(x), f(x)) == sol
def test_sysode_linear_neq_order1():
from sympy.abc import t
Z0 = Function('Z0')
Z1 = Function('Z1')
Z2 = Function('Z2')
Z3 = Function('Z3')
k01, k10, k20, k21, k23, k30 = symbols('k01 k10 k20 k21 k23 k30')
eq = (Eq(Derivative(Z0(t), t), -k01*Z0(t) + k10*Z1(t) + k20*Z2(t) + k30*Z3(t)), Eq(Derivative(Z1(t), t),
k01*Z0(t) - k10*Z1(t) + k21*Z2(t)), Eq(Derivative(Z2(t), t), -(k20 + k21 + k23)*Z2(t)), Eq(Derivative(Z3(t),
t), k23*Z2(t) - k30*Z3(t)))
sols_eq = [Eq(Z0(t), C1*k10/k01 + C2*(-k10 + k30)*exp(-k30*t)/(k01 + k10 - k30) - C3*exp(t*(-
k01 - k10)) + C4*(k10*k20 + k10*k21 - k10*k30 - k20**2 - k20*k21 - k20*k23 + k20*k30 +
k23*k30)*exp(t*(-k20 - k21 - k23))/(k23*(k01 + k10 - k20 - k21 - k23))),
Eq(Z1(t), C1 - C2*k01*exp(-k30*t)/(k01 + k10 - k30) + C3*exp(t*(-k01 - k10)) + C4*(k01*k20 + k01*k21
- k01*k30 - k20*k21 - k21**2 - k21*k23 + k21*k30)*exp(t*(-k20 - k21 - k23))/(k23*(k01 + k10 - k20 -
k21 - k23))),
Eq(Z2(t), C4*(-k20 - k21 - k23 + k30)*exp(t*(-k20 - k21 - k23))/k23),
Eq(Z3(t), C2*exp(-k30*t) + C4*exp(t*(-k20 - k21 - k23)))]
assert dsolve(eq, simplify=False) == sols_eq
def test_nth_algebraic():
eqn = Eq(Derivative(f(x), x), Derivative(g(x), x))
sol = Eq(f(x), C1 + g(x))
assert checkodesol(eqn, sol, order=1, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
eqn = (diff(f(x)) - x)*(diff(f(x)) + x)
sol = [Eq(f(x), C1 - x**2/2), Eq(f(x), C1 + x**2/2)]
assert checkodesol(eqn, sol, order=1, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
eqn = (1 - sin(f(x))) * f(x).diff(x)
sol = Eq(f(x), C1)
assert checkodesol(eqn, sol, order=1, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
M, m, r, t = symbols('M m r t')
phi = Function('phi')
eqn = Eq(-M * phi(t).diff(t),
Rational(3, 2) * m * r**2 * phi(t).diff(t) * phi(t).diff(t,t))
solns = [Eq(phi(t), C1), Eq(phi(t), C1 + C2*t - M*t**2/(3*m*r**2))]
assert checkodesol(eqn, solns[0], order=2, solve_for_func=False)[0]
assert checkodesol(eqn, solns[1], order=2, solve_for_func=False)[0]
assert set(solns) == set(dsolve(eqn, phi(t), hint='nth_algebraic'))
assert set(solns) == set(dsolve(eqn, phi(t)))
eqn = f(x) * f(x).diff(x) * f(x).diff(x, x)
sol = Eq(f(x), C1 + C2*x)
assert checkodesol(eqn, sol, order=1, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
eqn = f(x) * f(x).diff(x) * f(x).diff(x, x) * (f(x) - 1)
sol = Eq(f(x), C1 + C2*x)
assert checkodesol(eqn, sol, order=1, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
eqn = f(x) * f(x).diff(x) * f(x).diff(x, x) * (f(x) - 1) * (f(x).diff(x) - x)
solns = [Eq(f(x), C1 + x**2/2), Eq(f(x), C1 + C2*x)]
assert checkodesol(eqn, solns[0], order=2, solve_for_func=False)[0]
assert checkodesol(eqn, solns[1], order=2, solve_for_func=False)[0]
assert set(solns) == set(dsolve(eqn, f(x), hint='nth_algebraic'))
assert set(solns) == set(dsolve(eqn, f(x)))
def test_nth_algebraic_redundant_solutions():
# This one has a redundant solution that should be removed
eqn = f(x)*f(x).diff(x)
soln = Eq(f(x), C1)
assert checkodesol(eqn, soln, order=1, solve_for_func=False)[0]
assert soln == dsolve(eqn, f(x), hint='nth_algebraic')
assert soln == dsolve(eqn, f(x))
# This has two integral solutions and no algebraic solutions
eqn = (diff(f(x)) - x)*(diff(f(x)) + x)
sol = [Eq(f(x), C1 - x**2/2), Eq(f(x), C1 + x**2/2)]
assert all(c[0] for c in checkodesol(eqn, sol, order=1, solve_for_func=False))
assert set(sol) == set(dsolve(eqn, f(x), hint='nth_algebraic'))
assert set(sol) == set(dsolve(eqn, f(x)))
# This one doesn't work with dsolve at the time of writing but the
# redundancy checking code should not remove the algebraic solution.
from sympy.solvers.ode import _nth_algebraic_remove_redundant_solutions
eqn = f(x) + f(x)*f(x).diff(x)
solns = [Eq(f(x), 0),
Eq(f(x), C1 - x)]
solns_final = _nth_algebraic_remove_redundant_solutions(eqn, solns, 1, x)
assert all(c[0] for c in checkodesol(eqn, solns, order=1, solve_for_func=False))
assert set(solns) == set(solns_final)
solns = [Eq(f(x), exp(x)),
Eq(f(x), C1*exp(C2*x))]
solns_final = _nth_algebraic_remove_redundant_solutions(eqn, solns, 2, x)
assert solns_final == [Eq(f(x), C1*exp(C2*x))]
# This one needs a substitution f' = g.
eqn = -exp(x) + (x*Derivative(f(x), (x, 2)) + Derivative(f(x), x))/x
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x))
#
# These tests can be combined with the above test if they get fixed
# so that dsolve actually works in all these cases.
#
# Fails due to division by f(x) eliminating the solution before nth_algebraic
# is called.
@XFAIL
def test_nth_algebraic_find_multiple1():
eqn = f(x) + f(x)*f(x).diff(x)
solns = [Eq(f(x), 0),
Eq(f(x), C1 - x)]
assert all(c[0] for c in checkodesol(eqn, solns, order=1, solve_for_func=False))
assert set(solns) == set(dsolve(eqn, f(x)))
# prep = True breaks this
def test_nth_algebraic_noprep1():
eqn = Derivative(x*f(x), x, x, x)
sol = Eq(f(x), (C1 + C2*x + C3*x**2) / x)
assert checkodesol(eqn, sol, order=3, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), prep=False, hint='nth_algebraic')
@XFAIL
def test_nth_algebraic_prep1():
eqn = Derivative(x*f(x), x, x, x)
sol = Eq(f(x), (C1 + C2*x + C3*x**2) / x)
assert checkodesol(eqn, sol, order=3, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), prep=True, hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
# prep = True breaks this
def test_nth_algebraic_noprep2():
eqn = Eq(Derivative(x*Derivative(f(x), x), x)/x, exp(x))
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), prep=False, hint='nth_algebraic')
@XFAIL
def test_nth_algebraic_prep2():
eqn = Eq(Derivative(x*Derivative(f(x), x), x)/x, exp(x))
sol = Eq(f(x), C1 + C2*log(x) + exp(x) - Ei(x))
assert checkodesol(eqn, sol, order=2, solve_for_func=False)[0]
assert sol == dsolve(eqn, f(x), prep=True, hint='nth_algebraic')
assert sol == dsolve(eqn, f(x))
# This needs a combination of solutions from nth_algebraic and some other
# method from dsolve
@XFAIL
def test_nth_algebraic_find_multiple2():
eqn = f(x)**2 + f(x)*f(x).diff(x)
solns = [Eq(f(x), 0),
Eq(f(x), C1*exp(-x))]
assert all(c[0] for c in checkodesol(eqn, solns, order=1, solve_for_func=False))
assert set(solns) == dsolve(eqn, f(x))
# Needs to be a way to know how to combine derivatives in the expression
@XFAIL
def test_factoring_ode():
eqn = Derivative(x*f(x), x, x, x) + Derivative(f(x), x, x, x)
soln = Eq(f(x), (C1*x**2/2 + C2*x + C3 - x)/(1 + x))
assert checkodesol(eqn, soln, order=2, solve_for_func=False)[0]
assert soln == dsolve(eqn, f(x))
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16a6cc025f9eeb716117d029f54101c7905ca2cc214ff8537b1d7c05b87f2734
|
from sympy import Eq, factorial, Function, Lambda, rf, S, sqrt, symbols, I, expand_func, binomial, gamma
from sympy.solvers.recurr import rsolve, rsolve_hyper, rsolve_poly, rsolve_ratio
from sympy.utilities.pytest import raises
from sympy.core.compatibility import range
from sympy.abc import a, b, c
y = Function('y')
n, k = symbols('n,k', integer=True)
C0, C1, C2 = symbols('C0,C1,C2')
def test_rsolve_poly():
assert rsolve_poly([-1, -1, 1], 0, n) == 0
assert rsolve_poly([-1, -1, 1], 1, n) == -1
assert rsolve_poly([-1, n + 1], n, n) == 1
assert rsolve_poly([-1, 1], n, n) == C0 + (n**2 - n)/2
assert rsolve_poly([-n - 1, n], 1, n) == C1*n - 1
assert rsolve_poly([-4*n - 2, 1], 4*n + 1, n) == -1
assert rsolve_poly([-1, 1], n**5 + n**3, n) == \
C0 - n**3 / 2 - n**5 / 2 + n**2 / 6 + n**6 / 6 + 2*n**4 / 3
def test_rsolve_ratio():
solution = rsolve_ratio([-2*n**3 + n**2 + 2*n - 1, 2*n**3 + n**2 - 6*n,
-2*n**3 - 11*n**2 - 18*n - 9, 2*n**3 + 13*n**2 + 22*n + 8], 0, n)
assert solution in [
C1*((-2*n + 3)/(n**2 - 1))/3,
(S(1)/2)*(C1*(-3 + 2*n)/(-1 + n**2)),
(S(1)/2)*(C1*( 3 - 2*n)/( 1 - n**2)),
(S(1)/2)*(C2*(-3 + 2*n)/(-1 + n**2)),
(S(1)/2)*(C2*( 3 - 2*n)/( 1 - n**2)),
]
def test_rsolve_hyper():
assert rsolve_hyper([-1, -1, 1], 0, n) in [
C0*(S.Half - S.Half*sqrt(5))**n + C1*(S.Half + S.Half*sqrt(5))**n,
C1*(S.Half - S.Half*sqrt(5))**n + C0*(S.Half + S.Half*sqrt(5))**n,
]
assert rsolve_hyper([n**2 - 2, -2*n - 1, 1], 0, n) in [
C0*rf(sqrt(2), n) + C1*rf(-sqrt(2), n),
C1*rf(sqrt(2), n) + C0*rf(-sqrt(2), n),
]
assert rsolve_hyper([n**2 - k, -2*n - 1, 1], 0, n) in [
C0*rf(sqrt(k), n) + C1*rf(-sqrt(k), n),
C1*rf(sqrt(k), n) + C0*rf(-sqrt(k), n),
]
assert rsolve_hyper(
[2*n*(n + 1), -n**2 - 3*n + 2, n - 1], 0, n) == C1*factorial(n) + C0*2**n
assert rsolve_hyper(
[n + 2, -(2*n + 3)*(17*n**2 + 51*n + 39), n + 1], 0, n) == None
assert rsolve_hyper([-n - 1, -1, 1], 0, n) == None
assert rsolve_hyper([-1, 1], n, n).expand() == C0 + n**2/2 - n/2
assert rsolve_hyper([-1, 1], 1 + n, n).expand() == C0 + n**2/2 + n/2
assert rsolve_hyper([-1, 1], 3*(n + n**2), n).expand() == C0 + n**3 - n
assert rsolve_hyper([-a, 1],0,n).expand() == C0*a**n
assert rsolve_hyper([-a, 0, 1], 0, n).expand() == (-1)**n*C1*a**(n/2) + C0*a**(n/2)
assert rsolve_hyper([1, 1, 1], 0, n).expand() == \
C0*(-S(1)/2 - sqrt(3)*I/2)**n + C1*(-S(1)/2 + sqrt(3)*I/2)**n
assert rsolve_hyper([1, -2*n/a - 2/a, 1], 0, n) is None
def recurrence_term(c, f):
"""Compute RHS of recurrence in f(n) with coefficients in c."""
return sum(c[i]*f.subs(n, n + i) for i in range(len(c)))
def test_rsolve_bulk():
"""Some bulk-generated tests."""
funcs = [ n, n + 1, n**2, n**3, n**4, n + n**2, 27*n + 52*n**2 - 3*
n**3 + 12*n**4 - 52*n**5 ]
coeffs = [ [-2, 1], [-2, -1, 1], [-1, 1, 1, -1, 1], [-n, 1], [n**2 -
n + 12, 1] ]
for p in funcs:
# compute difference
for c in coeffs:
q = recurrence_term(c, p)
if p.is_polynomial(n):
assert rsolve_poly(c, q, n) == p
# See issue 3956:
#if p.is_hypergeometric(n):
# assert rsolve_hyper(c, q, n) == p
def test_rsolve():
f = y(n + 2) - y(n + 1) - y(n)
h = sqrt(5)*(S.Half + S.Half*sqrt(5))**n \
- sqrt(5)*(S.Half - S.Half*sqrt(5))**n
assert rsolve(f, y(n)) in [
C0*(S.Half - S.Half*sqrt(5))**n + C1*(S.Half + S.Half*sqrt(5))**n,
C1*(S.Half - S.Half*sqrt(5))**n + C0*(S.Half + S.Half*sqrt(5))**n,
]
assert rsolve(f, y(n), [0, 5]) == h
assert rsolve(f, y(n), {0: 0, 1: 5}) == h
assert rsolve(f, y(n), {y(0): 0, y(1): 5}) == h
assert rsolve(y(n) - y(n - 1) - y(n - 2), y(n), [0, 5]) == h
assert rsolve(Eq(y(n), y(n - 1) + y(n - 2)), y(n), [0, 5]) == h
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = (n - 1)*y(n + 2) - (n**2 + 3*n - 2)*y(n + 1) + 2*n*(n + 1)*y(n)
g = C1*factorial(n) + C0*2**n
h = -3*factorial(n) + 3*2**n
assert rsolve(f, y(n)) == g
assert rsolve(f, y(n), []) == g
assert rsolve(f, y(n), {}) == g
assert rsolve(f, y(n), [0, 3]) == h
assert rsolve(f, y(n), {0: 0, 1: 3}) == h
assert rsolve(f, y(n), {y(0): 0, y(1): 3}) == h
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - y(n - 1) - 2
assert rsolve(f, y(n), {y(0): 0}) == 2*n
assert rsolve(f, y(n), {y(0): 1}) == 2*n + 1
assert rsolve(f, y(n), {y(0): 0, y(1): 1}) is None
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = 3*y(n - 1) - y(n) - 1
assert rsolve(f, y(n), {y(0): 0}) == -3**n/2 + S.Half
assert rsolve(f, y(n), {y(0): 1}) == 3**n/2 + S.Half
assert rsolve(f, y(n), {y(0): 2}) == 3*3**n/2 + S.Half
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - 1/n*y(n - 1)
assert rsolve(f, y(n)) == C0/factorial(n)
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = y(n) - 1/n*y(n - 1) - 1
assert rsolve(f, y(n)) is None
f = 2*y(n - 1) + (1 - n)*y(n)/n
assert rsolve(f, y(n), {y(1): 1}) == 2**(n - 1)*n
assert rsolve(f, y(n), {y(1): 2}) == 2**(n - 1)*n*2
assert rsolve(f, y(n), {y(1): 3}) == 2**(n - 1)*n*3
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
f = (n - 1)*(n - 2)*y(n + 2) - (n + 1)*(n + 2)*y(n)
assert rsolve(f, y(n), {y(3): 6, y(4): 24}) == n*(n - 1)*(n - 2)
assert rsolve(
f, y(n), {y(3): 6, y(4): -24}) == -n*(n - 1)*(n - 2)*(-1)**(n)
assert f.subs(y, Lambda(k, rsolve(f, y(n)).subs(n, k))).simplify() == 0
assert rsolve(Eq(y(n + 1), a*y(n)), y(n), {y(1): a}).simplify() == a**n
assert rsolve(y(n) - a*y(n-2),y(n), \
{y(1): sqrt(a)*(a + b), y(2): a*(a - b)}).simplify() == \
a**(n/2)*(-(-1)**n*b + a)
f = (-16*n**2 + 32*n - 12)*y(n - 1) + (4*n**2 - 12*n + 9)*y(n)
assert expand_func(rsolve(f, y(n), \
{y(1): binomial(2*n + 1, 3)}).rewrite(gamma)).simplify() == \
2**(2*n)*n*(2*n - 1)*(4*n**2 - 1)/12
assert (rsolve(y(n) + a*(y(n + 1) + y(n - 1))/2, y(n)) -
(C0*((sqrt(-a**2 + 1) - 1)/a)**n +
C1*((-sqrt(-a**2 + 1) - 1)/a)**n)).simplify() == 0
assert rsolve((k + 1)*y(k), y(k)) is None
assert (rsolve((k + 1)*y(k) + (k + 3)*y(k + 1) + (k + 5)*y(k + 2), y(k))
is None)
def test_rsolve_raises():
x = Function('x')
raises(ValueError, lambda: rsolve(y(n) - y(k + 1), y(n)))
raises(ValueError, lambda: rsolve(y(n) - y(n + 1), x(n)))
raises(ValueError, lambda: rsolve(y(n) - x(n + 1), y(n)))
raises(ValueError, lambda: rsolve(y(n) - sqrt(n)*y(n + 1), y(n)))
raises(ValueError, lambda: rsolve(y(n) - y(n + 1), y(n), {x(0): 0}))
def test_issue_6844():
f = y(n + 2) - y(n + 1) + y(n)/4
assert rsolve(f, y(n)) == 2**(-n)*(C0 + C1*n)
assert rsolve(f, y(n), {y(0): 0, y(1): 1}) == 2*2**(-n)*n
def test_issue_15751():
f = y(n) + 21*y(n + 1) - 273*y(n + 2) - 1092*y(n + 3) + 1820*y(n + 4) + 1092*y(n + 5) - 273*y(n + 6) - 21*y(n + 7) + y(n + 8)
assert rsolve(f, y(n)) is not None
|
042a5e5e34dbe861a996227aee10612085e3868faa14339dde0f385d9e624305
|
"""Module with some functions for MathML, like transforming MathML
content in MathML presentation.
To use this module, you will need lxml.
"""
from sympy.utilities.pkgdata import get_resource
from sympy.utilities.decorator import doctest_depends_on
import xml.dom.minidom
__doctest_requires__ = {('apply_xsl', 'c2p'): ['lxml']}
def add_mathml_headers(s):
return """<math xmlns:mml="http://www.w3.org/1998/Math/MathML"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/1998/Math/MathML
http://www.w3.org/Math/XMLSchema/mathml2/mathml2.xsd">""" + s + "</math>"
@doctest_depends_on(modules=('lxml',))
def apply_xsl(mml, xsl):
"""Apply a xsl to a MathML string
@param mml: a string with MathML code
@param xsl: a string representing a path to a xsl (xml stylesheet)
file. This file name is relative to the PYTHONPATH
>>> from sympy.utilities.mathml import apply_xsl
>>> xsl = 'mathml/data/simple_mmlctop.xsl'
>>> mml = '<apply> <plus/> <ci>a</ci> <ci>b</ci> </apply>'
>>> res = apply_xsl(mml,xsl)
>>> ''.join(res.splitlines())
'<?xml version="1.0"?><mrow xmlns="http://www.w3.org/1998/Math/MathML"> <mi>a</mi> <mo> + </mo> <mi>b</mi></mrow>'
"""
from lxml import etree
s = etree.XML(get_resource(xsl).read())
transform = etree.XSLT(s)
doc = etree.XML(mml)
result = transform(doc)
s = str(result)
return s
@doctest_depends_on(modules=('lxml',))
def c2p(mml, simple=False):
"""Transforms a document in MathML content (like the one that sympy produces)
in one document in MathML presentation, more suitable for printing, and more
widely accepted
>>> from sympy.utilities.mathml import c2p
>>> mml = '<apply> <exp/> <cn>2</cn> </apply>'
>>> c2p(mml,simple=True) != c2p(mml,simple=False)
True
"""
if not mml.startswith('<math'):
mml = add_mathml_headers(mml)
if simple:
return apply_xsl(mml, 'mathml/data/simple_mmlctop.xsl')
return apply_xsl(mml, 'mathml/data/mmlctop.xsl')
|
ff35c20f04ed78ddc6d09a8e897b80d33710e10abe2a6bf6c4890b59a7a693cb
|
# Tests that require installed backends go into
# sympy/test_external/test_autowrap
import os
import tempfile
import shutil
import tempfile
from sympy.core import symbols, Eq
from sympy.core.compatibility import StringIO
from sympy.utilities.pytest import raises
from sympy.utilities.autowrap import (autowrap, binary_function,
CythonCodeWrapper, ufuncify, UfuncifyCodeWrapper, CodeWrapper)
from sympy.utilities.codegen import (
CCodeGen, C99CodeGen, CodeGenArgumentListError, make_routine
)
from sympy.utilities.tmpfiles import TmpFileManager, cleanup_tmp_files
def get_string(dump_fn, routines, prefix="file", **kwargs):
"""Wrapper for dump_fn. dump_fn writes its results to a stream object and
this wrapper returns the contents of that stream as a string. This
auxiliary function is used by many tests below.
The header and the empty lines are not generator to facilitate the
testing of the output.
"""
output = StringIO()
dump_fn(routines, output, prefix, **kwargs)
source = output.getvalue()
output.close()
return source
def test_cython_wrapper_scalar_function():
x, y, z = symbols('x,y,z')
expr = (x + y)*z
routine = make_routine("test", expr)
code_gen = CythonCodeWrapper(CCodeGen())
source = get_string(code_gen.dump_pyx, [routine])
expected = (
"cdef extern from 'file.h':\n"
" double test(double x, double y, double z)\n"
"\n"
"def test_c(double x, double y, double z):\n"
"\n"
" return test(x, y, z)")
assert source == expected
def test_cython_wrapper_outarg():
from sympy import Equality
x, y, z = symbols('x,y,z')
code_gen = CythonCodeWrapper(C99CodeGen())
routine = make_routine("test", Equality(z, x + y))
source = get_string(code_gen.dump_pyx, [routine])
expected = (
"cdef extern from 'file.h':\n"
" void test(double x, double y, double *z)\n"
"\n"
"def test_c(double x, double y):\n"
"\n"
" cdef double z = 0\n"
" test(x, y, &z)\n"
" return z")
assert source == expected
def test_cython_wrapper_inoutarg():
from sympy import Equality
x, y, z = symbols('x,y,z')
code_gen = CythonCodeWrapper(C99CodeGen())
routine = make_routine("test", Equality(z, x + y + z))
source = get_string(code_gen.dump_pyx, [routine])
expected = (
"cdef extern from 'file.h':\n"
" void test(double x, double y, double *z)\n"
"\n"
"def test_c(double x, double y, double z):\n"
"\n"
" test(x, y, &z)\n"
" return z")
assert source == expected
def test_cython_wrapper_compile_flags():
from sympy import Equality
x, y, z = symbols('x,y,z')
routine = make_routine("test", Equality(z, x + y))
code_gen = CythonCodeWrapper(CCodeGen())
expected = """\
try:
from setuptools import setup
from setuptools import Extension
except ImportError:
from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
cy_opts = {}
ext_mods = [Extension(
'wrapper_module_%(num)s', ['wrapper_module_%(num)s.pyx', 'wrapped_code_%(num)s.c'],
include_dirs=[],
library_dirs=[],
libraries=[],
extra_compile_args=['-std=c99'],
extra_link_args=[]
)]
setup(ext_modules=cythonize(ext_mods, **cy_opts))
""" % {'num': CodeWrapper._module_counter}
temp_dir = tempfile.mkdtemp()
TmpFileManager.tmp_folder(temp_dir)
setup_file_path = os.path.join(temp_dir, 'setup.py')
code_gen._prepare_files(routine, build_dir=temp_dir)
with open(setup_file_path) as f:
setup_text = f.read()
assert setup_text == expected
code_gen = CythonCodeWrapper(CCodeGen(),
include_dirs=['/usr/local/include', '/opt/booger/include'],
library_dirs=['/user/local/lib'],
libraries=['thelib', 'nilib'],
extra_compile_args=['-slow-math'],
extra_link_args=['-lswamp', '-ltrident'],
cythonize_options={'compiler_directives': {'boundscheck': False}}
)
expected = """\
try:
from setuptools import setup
from setuptools import Extension
except ImportError:
from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
cy_opts = {'compiler_directives': {'boundscheck': False}}
ext_mods = [Extension(
'wrapper_module_%(num)s', ['wrapper_module_%(num)s.pyx', 'wrapped_code_%(num)s.c'],
include_dirs=['/usr/local/include', '/opt/booger/include'],
library_dirs=['/user/local/lib'],
libraries=['thelib', 'nilib'],
extra_compile_args=['-slow-math', '-std=c99'],
extra_link_args=['-lswamp', '-ltrident']
)]
setup(ext_modules=cythonize(ext_mods, **cy_opts))
""" % {'num': CodeWrapper._module_counter}
code_gen._prepare_files(routine, build_dir=temp_dir)
with open(setup_file_path) as f:
setup_text = f.read()
assert setup_text == expected
expected = """\
try:
from setuptools import setup
from setuptools import Extension
except ImportError:
from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
cy_opts = {'compiler_directives': {'boundscheck': False}}
import numpy as np
ext_mods = [Extension(
'wrapper_module_%(num)s', ['wrapper_module_%(num)s.pyx', 'wrapped_code_%(num)s.c'],
include_dirs=['/usr/local/include', '/opt/booger/include', np.get_include()],
library_dirs=['/user/local/lib'],
libraries=['thelib', 'nilib'],
extra_compile_args=['-slow-math', '-std=c99'],
extra_link_args=['-lswamp', '-ltrident']
)]
setup(ext_modules=cythonize(ext_mods, **cy_opts))
""" % {'num': CodeWrapper._module_counter}
code_gen._need_numpy = True
code_gen._prepare_files(routine, build_dir=temp_dir)
with open(setup_file_path) as f:
setup_text = f.read()
assert setup_text == expected
TmpFileManager.cleanup()
def test_autowrap_dummy():
x, y, z = symbols('x y z')
# Uses DummyWrapper to test that codegen works as expected
f = autowrap(x + y, backend='dummy')
assert f() == str(x + y)
assert f.args == "x, y"
assert f.returns == "nameless"
f = autowrap(Eq(z, x + y), backend='dummy')
assert f() == str(x + y)
assert f.args == "x, y"
assert f.returns == "z"
f = autowrap(Eq(z, x + y + z), backend='dummy')
assert f() == str(x + y + z)
assert f.args == "x, y, z"
assert f.returns == "z"
def test_autowrap_args():
x, y, z = symbols('x y z')
raises(CodeGenArgumentListError, lambda: autowrap(Eq(z, x + y),
backend='dummy', args=[x]))
f = autowrap(Eq(z, x + y), backend='dummy', args=[y, x])
assert f() == str(x + y)
assert f.args == "y, x"
assert f.returns == "z"
raises(CodeGenArgumentListError, lambda: autowrap(Eq(z, x + y + z),
backend='dummy', args=[x, y]))
f = autowrap(Eq(z, x + y + z), backend='dummy', args=[y, x, z])
assert f() == str(x + y + z)
assert f.args == "y, x, z"
assert f.returns == "z"
f = autowrap(Eq(z, x + y + z), backend='dummy', args=(y, x, z))
assert f() == str(x + y + z)
assert f.args == "y, x, z"
assert f.returns == "z"
def test_autowrap_store_files():
x, y = symbols('x y')
tmp = tempfile.mkdtemp()
TmpFileManager.tmp_folder(tmp)
f = autowrap(x + y, backend='dummy', tempdir=tmp)
assert f() == str(x + y)
assert os.access(tmp, os.F_OK)
TmpFileManager.cleanup()
def test_autowrap_store_files_issue_gh12939():
x, y = symbols('x y')
tmp = './tmp'
try:
f = autowrap(x + y, backend='dummy', tempdir=tmp)
assert f() == str(x + y)
assert os.access(tmp, os.F_OK)
finally:
shutil.rmtree(tmp)
def test_binary_function():
x, y = symbols('x y')
f = binary_function('f', x + y, backend='dummy')
assert f._imp_() == str(x + y)
def test_ufuncify_source():
x, y, z = symbols('x,y,z')
code_wrapper = UfuncifyCodeWrapper(C99CodeGen("ufuncify"))
routine = make_routine("test", x + y + z)
source = get_string(code_wrapper.dump_c, [routine])
expected = """\
#include "Python.h"
#include "math.h"
#include "numpy/ndarraytypes.h"
#include "numpy/ufuncobject.h"
#include "numpy/halffloat.h"
#include "file.h"
static PyMethodDef wrapper_module_%(num)sMethods[] = {
{NULL, NULL, 0, NULL}
};
static void test_ufunc(char **args, npy_intp *dimensions, npy_intp* steps, void* data)
{
npy_intp i;
npy_intp n = dimensions[0];
char *in0 = args[0];
char *in1 = args[1];
char *in2 = args[2];
char *out0 = args[3];
npy_intp in0_step = steps[0];
npy_intp in1_step = steps[1];
npy_intp in2_step = steps[2];
npy_intp out0_step = steps[3];
for (i = 0; i < n; i++) {
*((double *)out0) = test(*(double *)in0, *(double *)in1, *(double *)in2);
in0 += in0_step;
in1 += in1_step;
in2 += in2_step;
out0 += out0_step;
}
}
PyUFuncGenericFunction test_funcs[1] = {&test_ufunc};
static char test_types[4] = {NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE};
static void *test_data[1] = {NULL};
#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef_HEAD_INIT,
"wrapper_module_%(num)s",
NULL,
-1,
wrapper_module_%(num)sMethods,
NULL,
NULL,
NULL,
NULL
};
PyMODINIT_FUNC PyInit_wrapper_module_%(num)s(void)
{
PyObject *m, *d;
PyObject *ufunc0;
m = PyModule_Create(&moduledef);
if (!m) {
return NULL;
}
import_array();
import_umath();
d = PyModule_GetDict(m);
ufunc0 = PyUFunc_FromFuncAndData(test_funcs, test_data, test_types, 1, 3, 1,
PyUFunc_None, "wrapper_module_%(num)s", "Created in SymPy with Ufuncify", 0);
PyDict_SetItemString(d, "test", ufunc0);
Py_DECREF(ufunc0);
return m;
}
#else
PyMODINIT_FUNC initwrapper_module_%(num)s(void)
{
PyObject *m, *d;
PyObject *ufunc0;
m = Py_InitModule("wrapper_module_%(num)s", wrapper_module_%(num)sMethods);
if (m == NULL) {
return;
}
import_array();
import_umath();
d = PyModule_GetDict(m);
ufunc0 = PyUFunc_FromFuncAndData(test_funcs, test_data, test_types, 1, 3, 1,
PyUFunc_None, "wrapper_module_%(num)s", "Created in SymPy with Ufuncify", 0);
PyDict_SetItemString(d, "test", ufunc0);
Py_DECREF(ufunc0);
}
#endif""" % {'num': CodeWrapper._module_counter}
assert source == expected
def test_ufuncify_source_multioutput():
x, y, z = symbols('x,y,z')
var_symbols = (x, y, z)
expr = x + y**3 + 10*z**2
code_wrapper = UfuncifyCodeWrapper(C99CodeGen("ufuncify"))
routines = [make_routine("func{}".format(i), expr.diff(var_symbols[i]), var_symbols) for i in range(len(var_symbols))]
source = get_string(code_wrapper.dump_c, routines, funcname='multitest')
expected = """\
#include "Python.h"
#include "math.h"
#include "numpy/ndarraytypes.h"
#include "numpy/ufuncobject.h"
#include "numpy/halffloat.h"
#include "file.h"
static PyMethodDef wrapper_module_%(num)sMethods[] = {
{NULL, NULL, 0, NULL}
};
static void multitest_ufunc(char **args, npy_intp *dimensions, npy_intp* steps, void* data)
{
npy_intp i;
npy_intp n = dimensions[0];
char *in0 = args[0];
char *in1 = args[1];
char *in2 = args[2];
char *out0 = args[3];
char *out1 = args[4];
char *out2 = args[5];
npy_intp in0_step = steps[0];
npy_intp in1_step = steps[1];
npy_intp in2_step = steps[2];
npy_intp out0_step = steps[3];
npy_intp out1_step = steps[4];
npy_intp out2_step = steps[5];
for (i = 0; i < n; i++) {
*((double *)out0) = func0(*(double *)in0, *(double *)in1, *(double *)in2);
*((double *)out1) = func1(*(double *)in0, *(double *)in1, *(double *)in2);
*((double *)out2) = func2(*(double *)in0, *(double *)in1, *(double *)in2);
in0 += in0_step;
in1 += in1_step;
in2 += in2_step;
out0 += out0_step;
out1 += out1_step;
out2 += out2_step;
}
}
PyUFuncGenericFunction multitest_funcs[1] = {&multitest_ufunc};
static char multitest_types[6] = {NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE, NPY_DOUBLE};
static void *multitest_data[1] = {NULL};
#if PY_VERSION_HEX >= 0x03000000
static struct PyModuleDef moduledef = {
PyModuleDef_HEAD_INIT,
"wrapper_module_%(num)s",
NULL,
-1,
wrapper_module_%(num)sMethods,
NULL,
NULL,
NULL,
NULL
};
PyMODINIT_FUNC PyInit_wrapper_module_%(num)s(void)
{
PyObject *m, *d;
PyObject *ufunc0;
m = PyModule_Create(&moduledef);
if (!m) {
return NULL;
}
import_array();
import_umath();
d = PyModule_GetDict(m);
ufunc0 = PyUFunc_FromFuncAndData(multitest_funcs, multitest_data, multitest_types, 1, 3, 3,
PyUFunc_None, "wrapper_module_%(num)s", "Created in SymPy with Ufuncify", 0);
PyDict_SetItemString(d, "multitest", ufunc0);
Py_DECREF(ufunc0);
return m;
}
#else
PyMODINIT_FUNC initwrapper_module_%(num)s(void)
{
PyObject *m, *d;
PyObject *ufunc0;
m = Py_InitModule("wrapper_module_%(num)s", wrapper_module_%(num)sMethods);
if (m == NULL) {
return;
}
import_array();
import_umath();
d = PyModule_GetDict(m);
ufunc0 = PyUFunc_FromFuncAndData(multitest_funcs, multitest_data, multitest_types, 1, 3, 3,
PyUFunc_None, "wrapper_module_%(num)s", "Created in SymPy with Ufuncify", 0);
PyDict_SetItemString(d, "multitest", ufunc0);
Py_DECREF(ufunc0);
}
#endif""" % {'num': CodeWrapper._module_counter}
assert source == expected
|
417ecc8b4a0fabccd25ecac9b7093b2b377e449ea9076ab00ce31b349f6752dd
|
from sympy.core.compatibility import range, unichr
from sympy.utilities.misc import translate, replace, ordinal
def test_translate():
abc = 'abc'
translate(abc, None, 'a') == 'bc'
translate(abc, None, '') == 'abc'
translate(abc, {'a': 'x'}, 'c') == 'xb'
assert translate(abc, {'a': 'bc'}, 'c') == 'bcb'
assert translate(abc, {'ab': 'x'}, 'c') == 'x'
assert translate(abc, {'ab': ''}, 'c') == ''
assert translate(abc, {'bc': 'x'}, 'c') == 'ab'
assert translate(abc, {'abc': 'x', 'a': 'y'}) == 'x'
u = unichr(4096)
assert translate(abc, 'a', 'x', u) == 'xbc'
assert (u in translate(abc, 'a', u, u)) is True
def test_replace():
assert replace('abc', ('a', 'b')) == 'bbc'
assert replace('abc', {'a': 'Aa'}) == 'Aabc'
assert replace('abc', ('a', 'b'), ('c', 'C')) == 'bbC'
def test_ordinal():
assert ordinal(-1) == '-1st'
assert ordinal(0) == '0th'
assert ordinal(1) == '1st'
assert ordinal(2) == '2nd'
assert ordinal(3) == '3rd'
assert all(ordinal(i).endswith('th') for i in range(4, 21))
assert ordinal(100) == '100th'
assert ordinal(101) == '101st'
assert ordinal(102) == '102nd'
assert ordinal(103) == '103rd'
assert ordinal(104) == '104th'
assert ordinal(200) == '200th'
assert all(ordinal(i) == str(i) + 'th' for i in range(-220, -203))
|
932222cfd09f1bd005a56373ee1677760186a0b7aa0fa5580f9fb61b2d367e76
|
import warnings
from sympy.utilities.pytest import (raises, warns, ignore_warnings,
warns_deprecated_sympy, Failed)
from sympy.utilities.exceptions import SymPyDeprecationWarning
# Test callables
def test_expected_exception_is_silent_callable():
def f():
raise ValueError()
raises(ValueError, f)
# Under pytest raises will raise Failed rather than AssertionError
def test_lack_of_exception_triggers_AssertionError_callable():
try:
raises(Exception, lambda: 1 + 1)
assert False
except Failed as e:
assert "DID NOT RAISE" in str(e)
def test_unexpected_exception_is_passed_through_callable():
def f():
raise ValueError("some error message")
try:
raises(TypeError, f)
assert False
except ValueError as e:
assert str(e) == "some error message"
# Test with statement
def test_expected_exception_is_silent_with():
with raises(ValueError):
raise ValueError()
def test_lack_of_exception_triggers_AssertionError_with():
try:
with raises(Exception):
1 + 1
assert False
except Failed as e:
assert "DID NOT RAISE" in str(e)
def test_unexpected_exception_is_passed_through_with():
try:
with raises(TypeError):
raise ValueError("some error message")
assert False
except ValueError as e:
assert str(e) == "some error message"
# Now we can use raises() instead of try/catch
# to test that a specific exception class is raised
def test_second_argument_should_be_callable_or_string():
raises(TypeError, lambda: raises("irrelevant", 42))
def test_warns_catches_warning():
with warnings.catch_warnings(record=True) as w:
with warns(UserWarning):
warnings.warn('this is the warning message')
assert len(w) == 0
def test_warns_raises_without_warning():
with raises(Failed):
with warns(UserWarning):
pass
def test_warns_hides_other_warnings():
# This isn't ideal but it's what pytest's warns does:
with warnings.catch_warnings(record=True) as w:
with warns(UserWarning):
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
assert len(w) == 0
def test_warns_continues_after_warning():
with warnings.catch_warnings(record=True) as w:
finished = False
with warns(UserWarning):
warnings.warn('this is the warning message')
finished = True
assert finished
assert len(w) == 0
def test_warns_many_warnings():
# This isn't ideal but it's what pytest's warns does:
with warnings.catch_warnings(record=True) as w:
finished = False
with warns(UserWarning):
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
warnings.warn('this is the other message', RuntimeWarning)
finished = True
assert finished
assert len(w) == 0
def test_warns_match_matching():
with warnings.catch_warnings(record=True) as w:
with warns(UserWarning, match='this is the warning message'):
warnings.warn('this is the warning message', UserWarning)
assert len(w) == 0
def test_warns_match_non_matching():
with warnings.catch_warnings(record=True) as w:
with raises(Failed):
with warns(UserWarning, match='this is the warning message'):
warnings.warn('this is not the expected warning message', UserWarning)
assert len(w) == 0
def _warn_sympy_deprecation():
SymPyDeprecationWarning(
feature="foo",
useinstead="bar",
issue=1,
deprecated_since_version="0.0.0").warn()
def test_warns_deprecated_sympy_catches_warning():
with warnings.catch_warnings(record=True) as w:
with warns_deprecated_sympy():
_warn_sympy_deprecation()
assert len(w) == 0
def test_warns_deprecated_sympy_raises_without_warning():
with raises(Failed):
with warns_deprecated_sympy():
pass
def test_warns_deprecated_sympy_hides_other_warnings():
# This isn't ideal but it's what pytest's deprecated_call does:
with warnings.catch_warnings(record=True) as w:
with warns_deprecated_sympy():
_warn_sympy_deprecation()
warnings.warn('this is the other message', RuntimeWarning)
assert len(w) == 0
def test_warns_deprecated_sympy_continues_after_warning():
with warnings.catch_warnings(record=True) as w:
finished = False
with warns_deprecated_sympy():
_warn_sympy_deprecation()
finished = True
assert finished
assert len(w) == 0
def test_warns_deprecated_sympy_many_warnings():
# This isn't ideal but it's what pytest's warns_deprecated_sympy does:
with warnings.catch_warnings(record=True) as w:
finished = False
with warns_deprecated_sympy():
_warn_sympy_deprecation()
warnings.warn('this is the other message', RuntimeWarning)
_warn_sympy_deprecation()
warnings.warn('this is the other message', RuntimeWarning)
warnings.warn('this is the other message', RuntimeWarning)
finished = True
assert finished
assert len(w) == 0
def test_ignore_ignores_warning():
with warnings.catch_warnings(record=True) as w:
with ignore_warnings(UserWarning):
warnings.warn('this is the warning message')
assert len(w) == 0
def test_ignore_does_not_raise_without_warning():
with warnings.catch_warnings(record=True) as w:
with ignore_warnings(UserWarning):
pass
assert len(w) == 0
def test_ignore_allows_other_warnings():
with warnings.catch_warnings(record=True) as w:
with ignore_warnings(UserWarning):
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
assert len(w) == 1
assert isinstance(w[0].message, RuntimeWarning)
assert str(w[0].message) == 'this is the other message'
def test_ignore_continues_after_warning():
with warnings.catch_warnings(record=True) as w:
finished = False
with ignore_warnings(UserWarning):
warnings.warn('this is the warning message')
finished = True
assert finished
assert len(w) == 0
def test_ignore_many_warnings():
with warnings.catch_warnings(record=True) as w:
with ignore_warnings(UserWarning):
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
warnings.warn('this is the warning message', UserWarning)
warnings.warn('this is the other message', RuntimeWarning)
warnings.warn('this is the other message', RuntimeWarning)
assert len(w) == 3
for wi in w:
assert isinstance(wi.message, RuntimeWarning)
assert str(wi.message) == 'this is the other message'
|
1a4a021f87667c78b33d86163de7a7d68d06b6747edfbdbe2e0a7b86d24868ae
|
from distutils.version import LooseVersion as V
from itertools import product
import math
import inspect
import mpmath
from sympy.utilities.pytest import XFAIL, raises
from sympy import (
symbols, lambdify, sqrt, sin, cos, tan, pi, acos, acosh, Rational,
Float, Matrix, Lambda, Piecewise, exp, Integral, oo, I, Abs, Function,
true, false, And, Or, Not, ITE, Min, Max, floor, diff, IndexedBase, Sum,
DotProduct, Eq, Dummy, sinc, erf, erfc, factorial, gamma, loggamma,
digamma, RisingFactorial, besselj, bessely, besseli, besselk, S,
MatrixSymbol, chebyshevt, chebyshevu, legendre, hermite, laguerre,
gegenbauer, assoc_legendre, assoc_laguerre, jacobi)
from sympy.printing.lambdarepr import LambdaPrinter
from sympy.printing.pycode import NumPyPrinter
from sympy.utilities.lambdify import implemented_function, lambdastr
from sympy.utilities.pytest import skip
from sympy.utilities.decorator import conserve_mpmath_dps
from sympy.external import import_module
from sympy.functions.special.gamma_functions import uppergamma,lowergamma
import sympy
MutableDenseMatrix = Matrix
numpy = import_module('numpy')
scipy = import_module('scipy')
scipy_special = import_module('scipy.special')
numexpr = import_module('numexpr')
tensorflow = import_module('tensorflow')
if tensorflow:
# Hide Tensorflow warnings
import os
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'
w, x, y, z = symbols('w,x,y,z')
#================== Test different arguments =======================
def test_no_args():
f = lambdify([], 1)
raises(TypeError, lambda: f(-1))
assert f() == 1
def test_single_arg():
f = lambdify(x, 2*x)
assert f(1) == 2
def test_list_args():
f = lambdify([x, y], x + y)
assert f(1, 2) == 3
def test_nested_args():
f1 = lambdify([[w, x]], [w, x])
assert f1([91, 2]) == [91, 2]
raises(TypeError, lambda: f1(1, 2))
f2 = lambdify([(w, x), (y, z)], [w, x, y, z])
assert f2((18, 12), (73, 4)) == [18, 12, 73, 4]
raises(TypeError, lambda: f2(3, 4))
f3 = lambdify([w, [[[x]], y], z], [w, x, y, z])
assert f3(10, [[[52]], 31], 44) == [10, 52, 31, 44]
def test_str_args():
f = lambdify('x,y,z', 'z,y,x')
assert f(3, 2, 1) == (1, 2, 3)
assert f(1.0, 2.0, 3.0) == (3.0, 2.0, 1.0)
# make sure correct number of args required
raises(TypeError, lambda: f(0))
def test_own_namespace_1():
myfunc = lambda x: 1
f = lambdify(x, sin(x), {"sin": myfunc})
assert f(0.1) == 1
assert f(100) == 1
def test_own_namespace_2():
def myfunc(x):
return 1
f = lambdify(x, sin(x), {'sin': myfunc})
assert f(0.1) == 1
assert f(100) == 1
def test_own_module():
f = lambdify(x, sin(x), math)
assert f(0) == 0.0
def test_bad_args():
# no vargs given
raises(TypeError, lambda: lambdify(1))
# same with vector exprs
raises(TypeError, lambda: lambdify([1, 2]))
def test_atoms():
# Non-Symbol atoms should not be pulled out from the expression namespace
f = lambdify(x, pi + x, {"pi": 3.14})
assert f(0) == 3.14
f = lambdify(x, I + x, {"I": 1j})
assert f(1) == 1 + 1j
#================== Test different modules =========================
# high precision output of sin(0.2*pi) is used to detect if precision is lost unwanted
@conserve_mpmath_dps
def test_sympy_lambda():
mpmath.mp.dps = 50
sin02 = mpmath.mpf("0.19866933079506121545941262711838975037020672954020")
f = lambdify(x, sin(x), "sympy")
assert f(x) == sin(x)
prec = 1e-15
assert -prec < f(Rational(1, 5)).evalf() - Float(str(sin02)) < prec
# arctan is in numpy module and should not be available
raises(NameError, lambda: lambdify(x, arctan(x), "sympy"))
@conserve_mpmath_dps
def test_math_lambda():
mpmath.mp.dps = 50
sin02 = mpmath.mpf("0.19866933079506121545941262711838975037020672954020")
f = lambdify(x, sin(x), "math")
prec = 1e-15
assert -prec < f(0.2) - sin02 < prec
raises(TypeError, lambda: f(x))
# if this succeeds, it can't be a python math function
@conserve_mpmath_dps
def test_mpmath_lambda():
mpmath.mp.dps = 50
sin02 = mpmath.mpf("0.19866933079506121545941262711838975037020672954020")
f = lambdify(x, sin(x), "mpmath")
prec = 1e-49 # mpmath precision is around 50 decimal places
assert -prec < f(mpmath.mpf("0.2")) - sin02 < prec
raises(TypeError, lambda: f(x))
# if this succeeds, it can't be a mpmath function
@conserve_mpmath_dps
def test_number_precision():
mpmath.mp.dps = 50
sin02 = mpmath.mpf("0.19866933079506121545941262711838975037020672954020")
f = lambdify(x, sin02, "mpmath")
prec = 1e-49 # mpmath precision is around 50 decimal places
assert -prec < f(0) - sin02 < prec
@conserve_mpmath_dps
def test_mpmath_precision():
mpmath.mp.dps = 100
assert str(lambdify((), pi.evalf(100), 'mpmath')()) == str(pi.evalf(100))
#================== Test Translations ==============================
# We can only check if all translated functions are valid. It has to be checked
# by hand if they are complete.
def test_math_transl():
from sympy.utilities.lambdify import MATH_TRANSLATIONS
for sym, mat in MATH_TRANSLATIONS.items():
assert sym in sympy.__dict__
assert mat in math.__dict__
def test_mpmath_transl():
from sympy.utilities.lambdify import MPMATH_TRANSLATIONS
for sym, mat in MPMATH_TRANSLATIONS.items():
assert sym in sympy.__dict__ or sym == 'Matrix'
assert mat in mpmath.__dict__
def test_numpy_transl():
if not numpy:
skip("numpy not installed.")
from sympy.utilities.lambdify import NUMPY_TRANSLATIONS
for sym, nump in NUMPY_TRANSLATIONS.items():
assert sym in sympy.__dict__
assert nump in numpy.__dict__
def test_scipy_transl():
if not scipy:
skip("scipy not installed.")
from sympy.utilities.lambdify import SCIPY_TRANSLATIONS
for sym, scip in SCIPY_TRANSLATIONS.items():
assert sym in sympy.__dict__
assert scip in scipy.__dict__ or scip in scipy.special.__dict__
def test_tensorflow_transl():
if not tensorflow:
skip("tensorflow not installed")
from sympy.utilities.lambdify import TENSORFLOW_TRANSLATIONS
for sym, tens in TENSORFLOW_TRANSLATIONS.items():
assert sym in sympy.__dict__
assert tens in tensorflow.__dict__
def test_numpy_translation_abs():
if not numpy:
skip("numpy not installed.")
f = lambdify(x, Abs(x), "numpy")
assert f(-1) == 1
assert f(1) == 1
def test_numexpr_printer():
if not numexpr:
skip("numexpr not installed.")
# if translation/printing is done incorrectly then evaluating
# a lambdified numexpr expression will throw an exception
from sympy.printing.lambdarepr import NumExprPrinter
blacklist = ('where', 'complex', 'contains')
arg_tuple = (x, y, z) # some functions take more than one argument
for sym in NumExprPrinter._numexpr_functions.keys():
if sym in blacklist:
continue
ssym = S(sym)
if hasattr(ssym, '_nargs'):
nargs = ssym._nargs[0]
else:
nargs = 1
args = arg_tuple[:nargs]
f = lambdify(args, ssym(*args), modules='numexpr')
assert f(*(1, )*nargs) is not None
def test_issue_9334():
if not numexpr:
skip("numexpr not installed.")
if not numpy:
skip("numpy not installed.")
expr = S('b*a - sqrt(a**2)')
a, b = sorted(expr.free_symbols, key=lambda s: s.name)
func_numexpr = lambdify((a,b), expr, modules=[numexpr], dummify=False)
foo, bar = numpy.random.random((2, 4))
func_numexpr(foo, bar)
#================== Test some functions ============================
def test_exponentiation():
f = lambdify(x, x**2)
assert f(-1) == 1
assert f(0) == 0
assert f(1) == 1
assert f(-2) == 4
assert f(2) == 4
assert f(2.5) == 6.25
def test_sqrt():
f = lambdify(x, sqrt(x))
assert f(0) == 0.0
assert f(1) == 1.0
assert f(4) == 2.0
assert abs(f(2) - 1.414) < 0.001
assert f(6.25) == 2.5
def test_trig():
f = lambdify([x], [cos(x), sin(x)], 'math')
d = f(pi)
prec = 1e-11
assert -prec < d[0] + 1 < prec
assert -prec < d[1] < prec
d = f(3.14159)
prec = 1e-5
assert -prec < d[0] + 1 < prec
assert -prec < d[1] < prec
#================== Test vectors ===================================
def test_vector_simple():
f = lambdify((x, y, z), (z, y, x))
assert f(3, 2, 1) == (1, 2, 3)
assert f(1.0, 2.0, 3.0) == (3.0, 2.0, 1.0)
# make sure correct number of args required
raises(TypeError, lambda: f(0))
def test_vector_discontinuous():
f = lambdify(x, (-1/x, 1/x))
raises(ZeroDivisionError, lambda: f(0))
assert f(1) == (-1.0, 1.0)
assert f(2) == (-0.5, 0.5)
assert f(-2) == (0.5, -0.5)
def test_trig_symbolic():
f = lambdify([x], [cos(x), sin(x)], 'math')
d = f(pi)
assert abs(d[0] + 1) < 0.0001
assert abs(d[1] - 0) < 0.0001
def test_trig_float():
f = lambdify([x], [cos(x), sin(x)])
d = f(3.14159)
assert abs(d[0] + 1) < 0.0001
assert abs(d[1] - 0) < 0.0001
def test_docs():
f = lambdify(x, x**2)
assert f(2) == 4
f = lambdify([x, y, z], [z, y, x])
assert f(1, 2, 3) == [3, 2, 1]
f = lambdify(x, sqrt(x))
assert f(4) == 2.0
f = lambdify((x, y), sin(x*y)**2)
assert f(0, 5) == 0
def test_math():
f = lambdify((x, y), sin(x), modules="math")
assert f(0, 5) == 0
def test_sin():
f = lambdify(x, sin(x)**2)
assert isinstance(f(2), float)
f = lambdify(x, sin(x)**2, modules="math")
assert isinstance(f(2), float)
def test_matrix():
A = Matrix([[x, x*y], [sin(z) + 4, x**z]])
sol = Matrix([[1, 2], [sin(3) + 4, 1]])
f = lambdify((x, y, z), A, modules="sympy")
assert f(1, 2, 3) == sol
f = lambdify((x, y, z), (A, [A]), modules="sympy")
assert f(1, 2, 3) == (sol, [sol])
J = Matrix((x, x + y)).jacobian((x, y))
v = Matrix((x, y))
sol = Matrix([[1, 0], [1, 1]])
assert lambdify(v, J, modules='sympy')(1, 2) == sol
assert lambdify(v.T, J, modules='sympy')(1, 2) == sol
def test_numpy_matrix():
if not numpy:
skip("numpy not installed.")
A = Matrix([[x, x*y], [sin(z) + 4, x**z]])
sol_arr = numpy.array([[1, 2], [numpy.sin(3) + 4, 1]])
#Lambdify array first, to ensure return to array as default
f = lambdify((x, y, z), A, ['numpy'])
numpy.testing.assert_allclose(f(1, 2, 3), sol_arr)
#Check that the types are arrays and matrices
assert isinstance(f(1, 2, 3), numpy.ndarray)
# gh-15071
class dot(Function):
pass
x_dot_mtx = dot(x, Matrix([[2], [1], [0]]))
f_dot1 = lambdify(x, x_dot_mtx)
inp = numpy.zeros((17, 3))
assert numpy.all(f_dot1(inp) == 0)
strict_kw = dict(allow_unknown_functions=False, inline=True, fully_qualified_modules=False)
p2 = NumPyPrinter(dict(user_functions={'dot': 'dot'}, **strict_kw))
f_dot2 = lambdify(x, x_dot_mtx, printer=p2)
assert numpy.all(f_dot2(inp) == 0)
p3 = NumPyPrinter(strict_kw)
# The line below should probably fail upon construction (before calling with "(inp)"):
raises(Exception, lambda: lambdify(x, x_dot_mtx, printer=p3)(inp))
def test_numpy_transpose():
if not numpy:
skip("numpy not installed.")
A = Matrix([[1, x], [0, 1]])
f = lambdify((x), A.T, modules="numpy")
numpy.testing.assert_array_equal(f(2), numpy.array([[1, 0], [2, 1]]))
def test_numpy_dotproduct():
if not numpy:
skip("numpy not installed")
A = Matrix([x, y, z])
f1 = lambdify([x, y, z], DotProduct(A, A), modules='numpy')
f2 = lambdify([x, y, z], DotProduct(A, A.T), modules='numpy')
f3 = lambdify([x, y, z], DotProduct(A.T, A), modules='numpy')
f4 = lambdify([x, y, z], DotProduct(A, A.T), modules='numpy')
assert f1(1, 2, 3) == \
f2(1, 2, 3) == \
f3(1, 2, 3) == \
f4(1, 2, 3) == \
numpy.array([14])
def test_numpy_inverse():
if not numpy:
skip("numpy not installed.")
A = Matrix([[1, x], [0, 1]])
f = lambdify((x), A**-1, modules="numpy")
numpy.testing.assert_array_equal(f(2), numpy.array([[1, -2], [0, 1]]))
def test_numpy_old_matrix():
if not numpy:
skip("numpy not installed.")
A = Matrix([[x, x*y], [sin(z) + 4, x**z]])
sol_arr = numpy.array([[1, 2], [numpy.sin(3) + 4, 1]])
f = lambdify((x, y, z), A, [{'ImmutableDenseMatrix': numpy.matrix}, 'numpy'])
numpy.testing.assert_allclose(f(1, 2, 3), sol_arr)
assert isinstance(f(1, 2, 3), numpy.matrix)
def test_python_div_zero_issue_11306():
if not numpy:
skip("numpy not installed.")
p = Piecewise((1 / x, y < -1), (x, y < 1), (1 / x, True))
f = lambdify([x, y], p, modules='numpy')
numpy.seterr(divide='ignore')
assert float(f(numpy.array([0]),numpy.array([0.5]))) == 0
assert str(float(f(numpy.array([0]),numpy.array([1])))) == 'inf'
numpy.seterr(divide='warn')
def test_issue9474():
mods = [None, 'math']
if numpy:
mods.append('numpy')
if mpmath:
mods.append('mpmath')
for mod in mods:
f = lambdify(x, S(1)/x, modules=mod)
assert f(2) == 0.5
f = lambdify(x, floor(S(1)/x), modules=mod)
assert f(2) == 0
for absfunc, modules in product([Abs, abs], mods):
f = lambdify(x, absfunc(x), modules=modules)
assert f(-1) == 1
assert f(1) == 1
assert f(3+4j) == 5
def test_issue_9871():
if not numexpr:
skip("numexpr not installed.")
if not numpy:
skip("numpy not installed.")
r = sqrt(x**2 + y**2)
expr = diff(1/r, x)
xn = yn = numpy.linspace(1, 10, 16)
# expr(xn, xn) = -xn/(sqrt(2)*xn)^3
fv_exact = -numpy.sqrt(2.)**-3 * xn**-2
fv_numpy = lambdify((x, y), expr, modules='numpy')(xn, yn)
fv_numexpr = lambdify((x, y), expr, modules='numexpr')(xn, yn)
numpy.testing.assert_allclose(fv_numpy, fv_exact, rtol=1e-10)
numpy.testing.assert_allclose(fv_numexpr, fv_exact, rtol=1e-10)
def test_numpy_piecewise():
if not numpy:
skip("numpy not installed.")
pieces = Piecewise((x, x < 3), (x**2, x > 5), (0, True))
f = lambdify(x, pieces, modules="numpy")
numpy.testing.assert_array_equal(f(numpy.arange(10)),
numpy.array([0, 1, 2, 0, 0, 0, 36, 49, 64, 81]))
# If we evaluate somewhere all conditions are False, we should get back NaN
nodef_func = lambdify(x, Piecewise((x, x > 0), (-x, x < 0)))
numpy.testing.assert_array_equal(nodef_func(numpy.array([-1, 0, 1])),
numpy.array([1, numpy.nan, 1]))
def test_numpy_logical_ops():
if not numpy:
skip("numpy not installed.")
and_func = lambdify((x, y), And(x, y), modules="numpy")
and_func_3 = lambdify((x, y, z), And(x, y, z), modules="numpy")
or_func = lambdify((x, y), Or(x, y), modules="numpy")
or_func_3 = lambdify((x, y, z), Or(x, y, z), modules="numpy")
not_func = lambdify((x), Not(x), modules="numpy")
arr1 = numpy.array([True, True])
arr2 = numpy.array([False, True])
arr3 = numpy.array([True, False])
numpy.testing.assert_array_equal(and_func(arr1, arr2), numpy.array([False, True]))
numpy.testing.assert_array_equal(and_func_3(arr1, arr2, arr3), numpy.array([False, False]))
numpy.testing.assert_array_equal(or_func(arr1, arr2), numpy.array([True, True]))
numpy.testing.assert_array_equal(or_func_3(arr1, arr2, arr3), numpy.array([True, True]))
numpy.testing.assert_array_equal(not_func(arr2), numpy.array([True, False]))
def test_numpy_matmul():
if not numpy:
skip("numpy not installed.")
xmat = Matrix([[x, y], [z, 1+z]])
ymat = Matrix([[x**2], [Abs(x)]])
mat_func = lambdify((x, y, z), xmat*ymat, modules="numpy")
numpy.testing.assert_array_equal(mat_func(0.5, 3, 4), numpy.array([[1.625], [3.5]]))
numpy.testing.assert_array_equal(mat_func(-0.5, 3, 4), numpy.array([[1.375], [3.5]]))
# Multiple matrices chained together in multiplication
f = lambdify((x, y, z), xmat*xmat*xmat, modules="numpy")
numpy.testing.assert_array_equal(f(0.5, 3, 4), numpy.array([[72.125, 119.25],
[159, 251]]))
def test_numpy_numexpr():
if not numpy:
skip("numpy not installed.")
if not numexpr:
skip("numexpr not installed.")
a, b, c = numpy.random.randn(3, 128, 128)
# ensure that numpy and numexpr return same value for complicated expression
expr = sin(x) + cos(y) + tan(z)**2 + Abs(z-y)*acos(sin(y*z)) + \
Abs(y-z)*acosh(2+exp(y-x))- sqrt(x**2+I*y**2)
npfunc = lambdify((x, y, z), expr, modules='numpy')
nefunc = lambdify((x, y, z), expr, modules='numexpr')
assert numpy.allclose(npfunc(a, b, c), nefunc(a, b, c))
def test_numexpr_userfunctions():
if not numpy:
skip("numpy not installed.")
if not numexpr:
skip("numexpr not installed.")
a, b = numpy.random.randn(2, 10)
uf = type('uf', (Function, ),
{'eval' : classmethod(lambda x, y : y**2+1)})
func = lambdify(x, 1-uf(x), modules='numexpr')
assert numpy.allclose(func(a), -(a**2))
uf = implemented_function(Function('uf'), lambda x, y : 2*x*y+1)
func = lambdify((x, y), uf(x, y), modules='numexpr')
assert numpy.allclose(func(a, b), 2*a*b+1)
def test_tensorflow_basic_math():
if not tensorflow:
skip("tensorflow not installed.")
expr = Max(sin(x), Abs(1/(x+2)))
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.constant(0, dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s) == 0.5
def test_tensorflow_placeholders():
if not tensorflow:
skip("tensorflow not installed.")
expr = Max(sin(x), Abs(1/(x+2)))
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.placeholder(dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s, feed_dict={a: 0}) == 0.5
def test_tensorflow_variables():
if not tensorflow:
skip("tensorflow not installed.")
expr = Max(sin(x), Abs(1/(x+2)))
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.Variable(0, dtype=tensorflow.float32)
s = tensorflow.Session()
if V(tensorflow.__version__) < '1.0':
s.run(tensorflow.initialize_all_variables())
else:
s.run(tensorflow.global_variables_initializer())
assert func(a).eval(session=s) == 0.5
def test_tensorflow_logical_operations():
if not tensorflow:
skip("tensorflow not installed.")
expr = Not(And(Or(x, y), y))
func = lambdify([x, y], expr, modules="tensorflow")
a = tensorflow.constant(False)
b = tensorflow.constant(True)
s = tensorflow.Session()
assert func(a, b).eval(session=s) == 0
def test_tensorflow_piecewise():
if not tensorflow:
skip("tensorflow not installed.")
expr = Piecewise((0, Eq(x,0)), (-1, x < 0), (1, x > 0))
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.placeholder(dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s, feed_dict={a: -1}) == -1
assert func(a).eval(session=s, feed_dict={a: 0}) == 0
assert func(a).eval(session=s, feed_dict={a: 1}) == 1
def test_tensorflow_multi_max():
if not tensorflow:
skip("tensorflow not installed.")
expr = Max(x, -x, x**2)
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.placeholder(dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s, feed_dict={a: -2}) == 4
def test_tensorflow_multi_min():
if not tensorflow:
skip("tensorflow not installed.")
expr = Min(x, -x, x**2)
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.placeholder(dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s, feed_dict={a: -2}) == -2
def test_tensorflow_relational():
if not tensorflow:
skip("tensorflow not installed.")
expr = x >= 0
func = lambdify(x, expr, modules="tensorflow")
a = tensorflow.placeholder(dtype=tensorflow.float32)
s = tensorflow.Session()
assert func(a).eval(session=s, feed_dict={a: 1})
def test_integral():
f = Lambda(x, exp(-x**2))
l = lambdify(x, Integral(f(x), (x, -oo, oo)), modules="sympy")
assert l(x) == Integral(exp(-x**2), (x, -oo, oo))
#================== Test symbolic ==================================
def test_sym_single_arg():
f = lambdify(x, x * y)
assert f(z) == z * y
def test_sym_list_args():
f = lambdify([x, y], x + y + z)
assert f(1, 2) == 3 + z
def test_sym_integral():
f = Lambda(x, exp(-x**2))
l = lambdify(x, Integral(f(x), (x, -oo, oo)), modules="sympy")
assert l(y).doit() == sqrt(pi)
def test_namespace_order():
# lambdify had a bug, such that module dictionaries or cached module
# dictionaries would pull earlier namespaces into themselves.
# Because the module dictionaries form the namespace of the
# generated lambda, this meant that the behavior of a previously
# generated lambda function could change as a result of later calls
# to lambdify.
n1 = {'f': lambda x: 'first f'}
n2 = {'f': lambda x: 'second f',
'g': lambda x: 'function g'}
f = sympy.Function('f')
g = sympy.Function('g')
if1 = lambdify(x, f(x), modules=(n1, "sympy"))
assert if1(1) == 'first f'
if2 = lambdify(x, g(x), modules=(n2, "sympy"))
# previously gave 'second f'
assert if1(1) == 'first f'
def test_namespace_type():
# lambdify had a bug where it would reject modules of type unicode
# on Python 2.
x = sympy.Symbol('x')
lambdify(x, x, modules=u'math')
def test_imps():
# Here we check if the default returned functions are anonymous - in
# the sense that we can have more than one function with the same name
f = implemented_function('f', lambda x: 2*x)
g = implemented_function('f', lambda x: math.sqrt(x))
l1 = lambdify(x, f(x))
l2 = lambdify(x, g(x))
assert str(f(x)) == str(g(x))
assert l1(3) == 6
assert l2(3) == math.sqrt(3)
# check that we can pass in a Function as input
func = sympy.Function('myfunc')
assert not hasattr(func, '_imp_')
my_f = implemented_function(func, lambda x: 2*x)
assert hasattr(my_f, '_imp_')
# Error for functions with same name and different implementation
f2 = implemented_function("f", lambda x: x + 101)
raises(ValueError, lambda: lambdify(x, f(f2(x))))
def test_imps_errors():
# Test errors that implemented functions can return, and still be able to
# form expressions.
# See: https://github.com/sympy/sympy/issues/10810
for val, error_class in product((0, 0., 2, 2.0),
(AttributeError, TypeError, ValueError)):
def myfunc(a):
if a == 0:
raise error_class
return 1
f = implemented_function('f', myfunc)
expr = f(val)
assert expr == f(val)
def test_imps_wrong_args():
raises(ValueError, lambda: implemented_function(sin, lambda x: x))
def test_lambdify_imps():
# Test lambdify with implemented functions
# first test basic (sympy) lambdify
f = sympy.cos
assert lambdify(x, f(x))(0) == 1
assert lambdify(x, 1 + f(x))(0) == 2
assert lambdify((x, y), y + f(x))(0, 1) == 2
# make an implemented function and test
f = implemented_function("f", lambda x: x + 100)
assert lambdify(x, f(x))(0) == 100
assert lambdify(x, 1 + f(x))(0) == 101
assert lambdify((x, y), y + f(x))(0, 1) == 101
# Can also handle tuples, lists, dicts as expressions
lam = lambdify(x, (f(x), x))
assert lam(3) == (103, 3)
lam = lambdify(x, [f(x), x])
assert lam(3) == [103, 3]
lam = lambdify(x, [f(x), (f(x), x)])
assert lam(3) == [103, (103, 3)]
lam = lambdify(x, {f(x): x})
assert lam(3) == {103: 3}
lam = lambdify(x, {f(x): x})
assert lam(3) == {103: 3}
lam = lambdify(x, {x: f(x)})
assert lam(3) == {3: 103}
# Check that imp preferred to other namespaces by default
d = {'f': lambda x: x + 99}
lam = lambdify(x, f(x), d)
assert lam(3) == 103
# Unless flag passed
lam = lambdify(x, f(x), d, use_imps=False)
assert lam(3) == 102
def test_dummification():
t = symbols('t')
F = Function('F')
G = Function('G')
#"\alpha" is not a valid python variable name
#lambdify should sub in a dummy for it, and return
#without a syntax error
alpha = symbols(r'\alpha')
some_expr = 2 * F(t)**2 / G(t)
lam = lambdify((F(t), G(t)), some_expr)
assert lam(3, 9) == 2
lam = lambdify(sin(t), 2 * sin(t)**2)
assert lam(F(t)) == 2 * F(t)**2
#Test that \alpha was properly dummified
lam = lambdify((alpha, t), 2*alpha + t)
assert lam(2, 1) == 5
raises(SyntaxError, lambda: lambdify(F(t) * G(t), F(t) * G(t) + 5))
raises(SyntaxError, lambda: lambdify(2 * F(t), 2 * F(t) + 5))
raises(SyntaxError, lambda: lambdify(2 * F(t), 4 * F(t) + 5))
def test_curly_matrix_symbol():
# Issue #15009
curlyv = sympy.MatrixSymbol("{v}", 2, 1)
lam = lambdify(curlyv, curlyv)
assert lam(1)==1
lam = lambdify(curlyv, curlyv, dummify=True)
assert lam(1)==1
def test_python_keywords():
# Test for issue 7452. The automatic dummification should ensure use of
# Python reserved keywords as symbol names will create valid lambda
# functions. This is an additional regression test.
python_if = symbols('if')
expr = python_if / 2
f = lambdify(python_if, expr)
assert f(4.0) == 2.0
def test_lambdify_docstring():
func = lambdify((w, x, y, z), w + x + y + z)
ref = (
"Created with lambdify. Signature:\n\n"
"func(w, x, y, z)\n\n"
"Expression:\n\n"
"w + x + y + z"
).splitlines()
assert func.__doc__.splitlines()[:len(ref)] == ref
syms = symbols('a1:26')
func = lambdify(syms, sum(syms))
ref = (
"Created with lambdify. Signature:\n\n"
"func(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15,\n"
" a16, a17, a18, a19, a20, a21, a22, a23, a24, a25)\n\n"
"Expression:\n\n"
"a1 + a10 + a11 + a12 + a13 + a14 + a15 + a16 + a17 + a18 + a19 + a2 + a20 +..."
).splitlines()
assert func.__doc__.splitlines()[:len(ref)] == ref
#================== Test special printers ==========================
def test_special_printers():
class IntervalPrinter(LambdaPrinter):
"""Use ``lambda`` printer but print numbers as ``mpi`` intervals. """
def _print_Integer(self, expr):
return "mpi('%s')" % super(IntervalPrinter, self)._print_Integer(expr)
def _print_Rational(self, expr):
return "mpi('%s')" % super(IntervalPrinter, self)._print_Rational(expr)
def intervalrepr(expr):
return IntervalPrinter().doprint(expr)
expr = sqrt(sqrt(2) + sqrt(3)) + S(1)/2
func0 = lambdify((), expr, modules="mpmath", printer=intervalrepr)
func1 = lambdify((), expr, modules="mpmath", printer=IntervalPrinter)
func2 = lambdify((), expr, modules="mpmath", printer=IntervalPrinter())
mpi = type(mpmath.mpi(1, 2))
assert isinstance(func0(), mpi)
assert isinstance(func1(), mpi)
assert isinstance(func2(), mpi)
def test_true_false():
# We want exact is comparison here, not just ==
assert lambdify([], true)() is True
assert lambdify([], false)() is False
def test_issue_2790():
assert lambdify((x, (y, z)), x + y)(1, (2, 4)) == 3
assert lambdify((x, (y, (w, z))), w + x + y + z)(1, (2, (3, 4))) == 10
assert lambdify(x, x + 1, dummify=False)(1) == 2
def test_issue_12092():
f = implemented_function('f', lambda x: x**2)
assert f(f(2)).evalf() == Float(16)
def test_issue_14911():
class Variable(sympy.Symbol):
def _sympystr(self, printer):
return printer.doprint(self.name)
_lambdacode = _sympystr
_numpycode = _sympystr
x = Variable('x')
y = 2 * x
code = LambdaPrinter().doprint(y)
assert code.replace(' ', '') == '2*x'
def test_ITE():
assert lambdify((x, y, z), ITE(x, y, z))(True, 5, 3) == 5
assert lambdify((x, y, z), ITE(x, y, z))(False, 5, 3) == 3
def test_Min_Max():
# see gh-10375
assert lambdify((x, y, z), Min(x, y, z))(1, 2, 3) == 1
assert lambdify((x, y, z), Max(x, y, z))(1, 2, 3) == 3
def test_Indexed():
# Issue #10934
if not numpy:
skip("numpy not installed")
a = IndexedBase('a')
i, j = symbols('i j')
b = numpy.array([[1, 2], [3, 4]])
assert lambdify(a, Sum(a[x, y], (x, 0, 1), (y, 0, 1)))(b) == 10
def test_issue_12173():
#test for issue 12173
exp1 = lambdify((x, y), uppergamma(x, y),"mpmath")(1, 2)
exp2 = lambdify((x, y), lowergamma(x, y),"mpmath")(1, 2)
assert exp1 == uppergamma(1, 2).evalf()
assert exp2 == lowergamma(1, 2).evalf()
def test_issue_13642():
if not numpy:
skip("numpy not installed")
f = lambdify(x, sinc(x))
assert Abs(f(1) - sinc(1)).n() < 1e-15
def test_sinc_mpmath():
f = lambdify(x, sinc(x), "mpmath")
assert Abs(f(1) - sinc(1)).n() < 1e-15
def test_lambdify_dummy_arg():
d1 = Dummy()
f1 = lambdify(d1, d1 + 1, dummify=False)
assert f1(2) == 3
f1b = lambdify(d1, d1 + 1)
assert f1b(2) == 3
d2 = Dummy('x')
f2 = lambdify(d2, d2 + 1)
assert f2(2) == 3
f3 = lambdify([[d2]], d2 + 1)
assert f3([2]) == 3
def test_lambdify_mixed_symbol_dummy_args():
d = Dummy()
# Contrived example of name clash
dsym = symbols(str(d))
f = lambdify([d, dsym], d - dsym)
assert f(4, 1) == 3
def test_numpy_array_arg():
# Test for issue 14655 (numpy part)
if not numpy:
skip("numpy not installed")
f = lambdify([[x, y]], x*x + y, 'numpy')
assert f(numpy.array([2.0, 1.0])) == 5
def test_tensorflow_array_arg():
# Test for issue 14655 (tensorflow part)
if not tensorflow:
skip("tensorflow not installed.")
f = lambdify([[x, y]], x*x + y, 'tensorflow')
fcall = f(tensorflow.constant([2.0, 1.0]))
s = tensorflow.Session()
assert s.run(fcall) == 5
def test_scipy_fns():
if not scipy:
skip("scipy not installed")
single_arg_sympy_fns = [erf, erfc, factorial, gamma, loggamma, digamma]
single_arg_scipy_fns = [scipy.special.erf, scipy.special.erfc,
scipy.special.factorial, scipy.special.gamma, scipy.special.gammaln,
scipy.special.psi]
numpy.random.seed(0)
for (sympy_fn, scipy_fn) in zip(single_arg_sympy_fns, single_arg_scipy_fns):
f = lambdify(x, sympy_fn(x), modules="scipy")
for i in range(20):
tv = numpy.random.uniform(-10, 10) + 1j*numpy.random.uniform(-5, 5)
# SciPy thinks that factorial(z) is 0 when re(z) < 0.
# SymPy does not think so.
if sympy_fn == factorial and numpy.real(tv) < 0:
tv = tv + 2*numpy.abs(numpy.real(tv))
# SciPy supports gammaln for real arguments only,
# and there is also a branch cut along the negative real axis
if sympy_fn == loggamma:
tv = numpy.abs(tv)
# SymPy's digamma evaluates as polygamma(0, z)
# which SciPy supports for real arguments only
if sympy_fn == digamma:
tv = numpy.real(tv)
sympy_result = sympy_fn(tv).evalf()
assert abs(f(tv) - sympy_result) < 1e-13*(1 + abs(sympy_result))
assert abs(f(tv) - scipy_fn(tv)) < 1e-13*(1 + abs(sympy_result))
double_arg_sympy_fns = [RisingFactorial, besselj, bessely, besseli,
besselk]
double_arg_scipy_fns = [scipy.special.poch, scipy.special.jv,
scipy.special.yv, scipy.special.iv, scipy.special.kv]
for (sympy_fn, scipy_fn) in zip(double_arg_sympy_fns, double_arg_scipy_fns):
f = lambdify((x, y), sympy_fn(x, y), modules="scipy")
for i in range(20):
# SciPy supports only real orders of Bessel functions
tv1 = numpy.random.uniform(-10, 10)
tv2 = numpy.random.uniform(-10, 10) + 1j*numpy.random.uniform(-5, 5)
# SciPy supports poch for real arguments only
if sympy_fn == RisingFactorial:
tv2 = numpy.real(tv2)
sympy_result = sympy_fn(tv1, tv2).evalf()
assert abs(f(tv1, tv2) - sympy_result) < 1e-13*(1 + abs(sympy_result))
assert abs(f(tv1, tv2) - scipy_fn(tv1, tv2)) < 1e-13*(1 + abs(sympy_result))
def test_scipy_polys():
if not scipy:
skip("scipy not installed")
numpy.random.seed(0)
params = symbols('n k a b')
# list polynomials with the number of parameters
polys = [
(chebyshevt, 1),
(chebyshevu, 1),
(legendre, 1),
(hermite, 1),
(laguerre, 1),
(gegenbauer, 2),
(assoc_legendre, 2),
(assoc_laguerre, 2),
(jacobi, 3)
]
for sympy_fn, num_params in polys:
args = params[:num_params] + (x,)
f = lambdify(args, sympy_fn(*args))
for i in range(10):
tn = numpy.random.randint(3, 10)
tparams = tuple(numpy.random.uniform(0, 5, size=num_params-1))
tv = numpy.random.uniform(-10, 10) + 1j*numpy.random.uniform(-5, 5)
# SciPy supports hermite for real arguments only
if sympy_fn == hermite:
tv = numpy.real(tv)
# assoc_legendre needs x in (-1, 1) and integer param at most n
if sympy_fn == assoc_legendre:
tv = numpy.random.uniform(-1, 1)
tparams = tuple(numpy.random.randint(1, tn, size=1))
vals = (tn,) + tparams + (tv,)
sympy_result = sympy_fn(*vals).evalf()
assert abs(f(*vals) - sympy_result) < 1e-13*(1 + abs(sympy_result))
def test_lambdify_inspect():
f = lambdify(x, x**2)
# Test that inspect.getsource works but don't hard-code implementation
# details
assert 'x**2' in inspect.getsource(f)
def test_issue_14941():
x, y = Dummy(), Dummy()
# test dict
f1 = lambdify([x, y], {x: 3, y: 3}, 'sympy')
assert f1(2, 3) == {2: 3, 3: 3}
# test tuple
f2 = lambdify([x, y], (y, x), 'sympy')
assert f2(2, 3) == (3, 2)
# test list
f3 = lambdify([x, y], [y, x], 'sympy')
assert f3(2, 3) == [3, 2]
def test_lambdify_Derivative_arg_issue_16468():
f = Function('f')(x)
fx = f.diff()
assert lambdify((f, fx), f + fx)(10, 5) == 15
assert eval(lambdastr((f, fx), f/fx))(10, 5) == 2
raises(SyntaxError, lambda:
eval(lambdastr((f, fx), f/fx, dummify=False)))
assert eval(lambdastr((f, fx), f/fx, dummify=True))(10, 5) == 2
assert eval(lambdastr((fx, f), f/fx, dummify=True))(S(10), 5) == S.Half
assert lambdify(fx, 1 + fx)(41) == 42
assert eval(lambdastr(fx, 1 + fx, dummify=True))(41) == 42
def test_imag_real():
f_re = lambdify([z], sympy.re(z))
val = 3+2j
assert f_re(val) == val.real
f_im = lambdify([z], sympy.im(z)) # see #15400
assert f_im(val) == val.imag
def test_MatrixSymbol_issue_15578():
if not numpy:
skip("numpy not installed")
A = MatrixSymbol('A', 2, 2)
A0 = numpy.array([[1, 2], [3, 4]])
f = lambdify(A, A**(-1))
assert numpy.allclose(f(A0), numpy.array([[-2., 1.], [1.5, -0.5]]))
g = lambdify(A, A**3)
assert numpy.allclose(g(A0), numpy.array([[37, 54], [81, 118]]))
def test_issue_15654():
if not scipy:
skip("scipy not installed")
from sympy.abc import n, l, r, Z
from sympy.physics import hydrogen
nv, lv, rv, Zv = 1, 0, 3, 1
sympy_value = hydrogen.R_nl(nv, lv, rv, Zv).evalf()
f = lambdify((n, l, r, Z), hydrogen.R_nl(n, l, r, Z))
scipy_value = f(nv, lv, rv, Zv)
assert abs(sympy_value - scipy_value) < 1e-15
|
1e78d9cf681c58dc85bcd12451e505e6b1fce999198b6e60cf70a4484c7e4867
|
from __future__ import print_function, division
import itertools
from sympy.core import S
from sympy.core.containers import Tuple
from sympy.core.function import _coeff_isneg
from sympy.core.mod import Mod
from sympy.core.mul import Mul
from sympy.core.numbers import Rational
from sympy.core.power import Pow
from sympy.core.relational import Equality
from sympy.core.symbol import Symbol
from sympy.printing.precedence import PRECEDENCE, precedence, precedence_traditional
from sympy.utilities import group
from sympy.utilities.iterables import has_variety
from sympy.core.sympify import SympifyError
from sympy.core.compatibility import range
from sympy.core.add import Add
from sympy.printing.printer import Printer
from sympy.printing.str import sstr
from sympy.printing.conventions import requires_partial
from .stringpict import prettyForm, stringPict
from .pretty_symbology import xstr, hobj, vobj, xobj, xsym, pretty_symbol, \
pretty_atom, pretty_use_unicode, pretty_try_use_unicode, greek_unicode, U, \
annotated
from sympy.utilities import default_sort_key
# rename for usage from outside
pprint_use_unicode = pretty_use_unicode
pprint_try_use_unicode = pretty_try_use_unicode
class PrettyPrinter(Printer):
"""Printer, which converts an expression into 2D ASCII-art figure."""
printmethod = "_pretty"
_default_settings = {
"order": None,
"full_prec": "auto",
"use_unicode": None,
"wrap_line": True,
"num_columns": None,
"use_unicode_sqrt_char": True,
}
def __init__(self, settings=None):
Printer.__init__(self, settings)
self.emptyPrinter = lambda x: prettyForm(xstr(x))
@property
def _use_unicode(self):
if self._settings['use_unicode']:
return True
else:
return pretty_use_unicode()
def doprint(self, expr):
return self._print(expr).render(**self._settings)
# empty op so _print(stringPict) returns the same
def _print_stringPict(self, e):
return e
def _print_basestring(self, e):
return prettyForm(e)
def _print_atan2(self, e):
pform = prettyForm(*self._print_seq(e.args).parens())
pform = prettyForm(*pform.left('atan2'))
return pform
def _print_Symbol(self, e):
symb = pretty_symbol(e.name)
return prettyForm(symb)
_print_RandomSymbol = _print_Symbol
def _print_Float(self, e):
# we will use StrPrinter's Float printer, but we need to handle the
# full_prec ourselves, according to the self._print_level
full_prec = self._settings["full_prec"]
if full_prec == "auto":
full_prec = self._print_level == 1
return prettyForm(sstr(e, full_prec=full_prec))
def _print_Cross(self, e):
vec1 = e._expr1
vec2 = e._expr2
pform = self._print(vec2)
pform = prettyForm(*pform.left('('))
pform = prettyForm(*pform.right(')'))
pform = prettyForm(*pform.left(self._print(U('MULTIPLICATION SIGN'))))
pform = prettyForm(*pform.left(')'))
pform = prettyForm(*pform.left(self._print(vec1)))
pform = prettyForm(*pform.left('('))
return pform
def _print_Curl(self, e):
vec = e._expr
pform = self._print(vec)
pform = prettyForm(*pform.left('('))
pform = prettyForm(*pform.right(')'))
pform = prettyForm(*pform.left(self._print(U('MULTIPLICATION SIGN'))))
pform = prettyForm(*pform.left(self._print(U('NABLA'))))
return pform
def _print_Divergence(self, e):
vec = e._expr
pform = self._print(vec)
pform = prettyForm(*pform.left('('))
pform = prettyForm(*pform.right(')'))
pform = prettyForm(*pform.left(self._print(U('DOT OPERATOR'))))
pform = prettyForm(*pform.left(self._print(U('NABLA'))))
return pform
def _print_Dot(self, e):
vec1 = e._expr1
vec2 = e._expr2
pform = self._print(vec2)
pform = prettyForm(*pform.left('('))
pform = prettyForm(*pform.right(')'))
pform = prettyForm(*pform.left(self._print(U('DOT OPERATOR'))))
pform = prettyForm(*pform.left(')'))
pform = prettyForm(*pform.left(self._print(vec1)))
pform = prettyForm(*pform.left('('))
return pform
def _print_Gradient(self, e):
func = e._expr
pform = self._print(func)
pform = prettyForm(*pform.left('('))
pform = prettyForm(*pform.right(')'))
pform = prettyForm(*pform.left(self._print(U('DOT OPERATOR'))))
pform = prettyForm(*pform.left(self._print(U('NABLA'))))
return pform
def _print_Atom(self, e):
try:
# print atoms like Exp1 or Pi
return prettyForm(pretty_atom(e.__class__.__name__))
except KeyError:
return self.emptyPrinter(e)
# Infinity inherits from Number, so we have to override _print_XXX order
_print_Infinity = _print_Atom
_print_NegativeInfinity = _print_Atom
_print_EmptySet = _print_Atom
_print_Naturals = _print_Atom
_print_Naturals0 = _print_Atom
_print_Integers = _print_Atom
_print_Complexes = _print_Atom
def _print_Reals(self, e):
if self._use_unicode:
return self._print_Atom(e)
else:
inf_list = ['-oo', 'oo']
return self._print_seq(inf_list, '(', ')')
def _print_subfactorial(self, e):
x = e.args[0]
pform = self._print(x)
# Add parentheses if needed
if not ((x.is_Integer and x.is_nonnegative) or x.is_Symbol):
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left('!'))
return pform
def _print_factorial(self, e):
x = e.args[0]
pform = self._print(x)
# Add parentheses if needed
if not ((x.is_Integer and x.is_nonnegative) or x.is_Symbol):
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.right('!'))
return pform
def _print_factorial2(self, e):
x = e.args[0]
pform = self._print(x)
# Add parentheses if needed
if not ((x.is_Integer and x.is_nonnegative) or x.is_Symbol):
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.right('!!'))
return pform
def _print_binomial(self, e):
n, k = e.args
n_pform = self._print(n)
k_pform = self._print(k)
bar = ' '*max(n_pform.width(), k_pform.width())
pform = prettyForm(*k_pform.above(bar))
pform = prettyForm(*pform.above(n_pform))
pform = prettyForm(*pform.parens('(', ')'))
pform.baseline = (pform.baseline + 1)//2
return pform
def _print_Relational(self, e):
op = prettyForm(' ' + xsym(e.rel_op) + ' ')
l = self._print(e.lhs)
r = self._print(e.rhs)
pform = prettyForm(*stringPict.next(l, op, r))
return pform
def _print_Not(self, e):
from sympy import Equivalent, Implies
if self._use_unicode:
arg = e.args[0]
pform = self._print(arg)
if isinstance(arg, Equivalent):
return self._print_Equivalent(arg, altchar=u"\N{LEFT RIGHT DOUBLE ARROW WITH STROKE}")
if isinstance(arg, Implies):
return self._print_Implies(arg, altchar=u"\N{RIGHTWARDS ARROW WITH STROKE}")
if arg.is_Boolean and not arg.is_Not:
pform = prettyForm(*pform.parens())
return prettyForm(*pform.left(u"\N{NOT SIGN}"))
else:
return self._print_Function(e)
def __print_Boolean(self, e, char, sort=True):
args = e.args
if sort:
args = sorted(e.args, key=default_sort_key)
arg = args[0]
pform = self._print(arg)
if arg.is_Boolean and not arg.is_Not:
pform = prettyForm(*pform.parens())
for arg in args[1:]:
pform_arg = self._print(arg)
if arg.is_Boolean and not arg.is_Not:
pform_arg = prettyForm(*pform_arg.parens())
pform = prettyForm(*pform.right(u' %s ' % char))
pform = prettyForm(*pform.right(pform_arg))
return pform
def _print_And(self, e):
if self._use_unicode:
return self.__print_Boolean(e, u"\N{LOGICAL AND}")
else:
return self._print_Function(e, sort=True)
def _print_Or(self, e):
if self._use_unicode:
return self.__print_Boolean(e, u"\N{LOGICAL OR}")
else:
return self._print_Function(e, sort=True)
def _print_Xor(self, e):
if self._use_unicode:
return self.__print_Boolean(e, u"\N{XOR}")
else:
return self._print_Function(e, sort=True)
def _print_Nand(self, e):
if self._use_unicode:
return self.__print_Boolean(e, u"\N{NAND}")
else:
return self._print_Function(e, sort=True)
def _print_Nor(self, e):
if self._use_unicode:
return self.__print_Boolean(e, u"\N{NOR}")
else:
return self._print_Function(e, sort=True)
def _print_Implies(self, e, altchar=None):
if self._use_unicode:
return self.__print_Boolean(e, altchar or u"\N{RIGHTWARDS ARROW}", sort=False)
else:
return self._print_Function(e)
def _print_Equivalent(self, e, altchar=None):
if self._use_unicode:
return self.__print_Boolean(e, altchar or u"\N{LEFT RIGHT DOUBLE ARROW}")
else:
return self._print_Function(e, sort=True)
def _print_conjugate(self, e):
pform = self._print(e.args[0])
return prettyForm( *pform.above( hobj('_', pform.width())) )
def _print_Abs(self, e):
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens('|', '|'))
return pform
_print_Determinant = _print_Abs
def _print_floor(self, e):
if self._use_unicode:
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens('lfloor', 'rfloor'))
return pform
else:
return self._print_Function(e)
def _print_ceiling(self, e):
if self._use_unicode:
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens('lceil', 'rceil'))
return pform
else:
return self._print_Function(e)
def _print_Derivative(self, deriv):
if requires_partial(deriv) and self._use_unicode:
deriv_symbol = U('PARTIAL DIFFERENTIAL')
else:
deriv_symbol = r'd'
x = None
count_total_deriv = 0
for sym, num in reversed(deriv.variable_count):
s = self._print(sym)
ds = prettyForm(*s.left(deriv_symbol))
count_total_deriv += num
if (not num.is_Integer) or (num > 1):
ds = ds**prettyForm(str(num))
if x is None:
x = ds
else:
x = prettyForm(*x.right(' '))
x = prettyForm(*x.right(ds))
f = prettyForm(
binding=prettyForm.FUNC, *self._print(deriv.expr).parens())
pform = prettyForm(deriv_symbol)
if (count_total_deriv > 1) != False:
pform = pform**prettyForm(str(count_total_deriv))
pform = prettyForm(*pform.below(stringPict.LINE, x))
pform.baseline = pform.baseline + 1
pform = prettyForm(*stringPict.next(pform, f))
pform.binding = prettyForm.MUL
return pform
def _print_Cycle(self, dc):
from sympy.combinatorics.permutations import Permutation, Cycle
# for Empty Cycle
if dc == Cycle():
cyc = stringPict('')
return prettyForm(*cyc.parens())
dc_list = Permutation(dc.list()).cyclic_form
# for Identity Cycle
if dc_list == []:
cyc = self._print(dc.size - 1)
return prettyForm(*cyc.parens())
cyc = stringPict('')
for i in dc_list:
l = self._print(str(tuple(i)).replace(',', ''))
cyc = prettyForm(*cyc.right(l))
return cyc
def _print_PDF(self, pdf):
lim = self._print(pdf.pdf.args[0])
lim = prettyForm(*lim.right(', '))
lim = prettyForm(*lim.right(self._print(pdf.domain[0])))
lim = prettyForm(*lim.right(', '))
lim = prettyForm(*lim.right(self._print(pdf.domain[1])))
lim = prettyForm(*lim.parens())
f = self._print(pdf.pdf.args[1])
f = prettyForm(*f.right(', '))
f = prettyForm(*f.right(lim))
f = prettyForm(*f.parens())
pform = prettyForm('PDF')
pform = prettyForm(*pform.right(f))
return pform
def _print_Integral(self, integral):
f = integral.function
# Add parentheses if arg involves addition of terms and
# create a pretty form for the argument
prettyF = self._print(f)
# XXX generalize parens
if f.is_Add:
prettyF = prettyForm(*prettyF.parens())
# dx dy dz ...
arg = prettyF
for x in integral.limits:
prettyArg = self._print(x[0])
# XXX qparens (parens if needs-parens)
if prettyArg.width() > 1:
prettyArg = prettyForm(*prettyArg.parens())
arg = prettyForm(*arg.right(' d', prettyArg))
# \int \int \int ...
firstterm = True
s = None
for lim in integral.limits:
x = lim[0]
# Create bar based on the height of the argument
h = arg.height()
H = h + 2
# XXX hack!
ascii_mode = not self._use_unicode
if ascii_mode:
H += 2
vint = vobj('int', H)
# Construct the pretty form with the integral sign and the argument
pform = prettyForm(vint)
pform.baseline = arg.baseline + (
H - h)//2 # covering the whole argument
if len(lim) > 1:
# Create pretty forms for endpoints, if definite integral.
# Do not print empty endpoints.
if len(lim) == 2:
prettyA = prettyForm("")
prettyB = self._print(lim[1])
if len(lim) == 3:
prettyA = self._print(lim[1])
prettyB = self._print(lim[2])
if ascii_mode: # XXX hack
# Add spacing so that endpoint can more easily be
# identified with the correct integral sign
spc = max(1, 3 - prettyB.width())
prettyB = prettyForm(*prettyB.left(' ' * spc))
spc = max(1, 4 - prettyA.width())
prettyA = prettyForm(*prettyA.right(' ' * spc))
pform = prettyForm(*pform.above(prettyB))
pform = prettyForm(*pform.below(prettyA))
if not ascii_mode: # XXX hack
pform = prettyForm(*pform.right(' '))
if firstterm:
s = pform # first term
firstterm = False
else:
s = prettyForm(*s.left(pform))
pform = prettyForm(*arg.left(s))
pform.binding = prettyForm.MUL
return pform
def _print_Product(self, expr):
func = expr.term
pretty_func = self._print(func)
horizontal_chr = xobj('_', 1)
corner_chr = xobj('_', 1)
vertical_chr = xobj('|', 1)
if self._use_unicode:
# use unicode corners
horizontal_chr = xobj('-', 1)
corner_chr = u'\N{BOX DRAWINGS LIGHT DOWN AND HORIZONTAL}'
func_height = pretty_func.height()
first = True
max_upper = 0
sign_height = 0
for lim in expr.limits:
width = (func_height + 2) * 5 // 3 - 2
sign_lines = []
sign_lines.append(corner_chr + (horizontal_chr*width) + corner_chr)
for i in range(func_height + 1):
sign_lines.append(vertical_chr + (' '*width) + vertical_chr)
pretty_sign = stringPict('')
pretty_sign = prettyForm(*pretty_sign.stack(*sign_lines))
pretty_upper = self._print(lim[2])
pretty_lower = self._print(Equality(lim[0], lim[1]))
max_upper = max(max_upper, pretty_upper.height())
if first:
sign_height = pretty_sign.height()
pretty_sign = prettyForm(*pretty_sign.above(pretty_upper))
pretty_sign = prettyForm(*pretty_sign.below(pretty_lower))
if first:
pretty_func.baseline = 0
first = False
height = pretty_sign.height()
padding = stringPict('')
padding = prettyForm(*padding.stack(*[' ']*(height - 1)))
pretty_sign = prettyForm(*pretty_sign.right(padding))
pretty_func = prettyForm(*pretty_sign.right(pretty_func))
pretty_func.baseline = max_upper + sign_height//2
pretty_func.binding = prettyForm.MUL
return pretty_func
def _print_Sum(self, expr):
ascii_mode = not self._use_unicode
def asum(hrequired, lower, upper, use_ascii):
def adjust(s, wid=None, how='<^>'):
if not wid or len(s) > wid:
return s
need = wid - len(s)
if how == '<^>' or how == "<" or how not in list('<^>'):
return s + ' '*need
half = need//2
lead = ' '*half
if how == ">":
return " "*need + s
return lead + s + ' '*(need - len(lead))
h = max(hrequired, 2)
d = h//2
w = d + 1
more = hrequired % 2
lines = []
if use_ascii:
lines.append("_"*(w) + ' ')
lines.append(r"\%s`" % (' '*(w - 1)))
for i in range(1, d):
lines.append('%s\\%s' % (' '*i, ' '*(w - i)))
if more:
lines.append('%s)%s' % (' '*(d), ' '*(w - d)))
for i in reversed(range(1, d)):
lines.append('%s/%s' % (' '*i, ' '*(w - i)))
lines.append("/" + "_"*(w - 1) + ',')
return d, h + more, lines, 0
else:
w = w + more
d = d + more
vsum = vobj('sum', 4)
lines.append("_"*(w))
for i in range(0, d):
lines.append('%s%s%s' % (' '*i, vsum[2], ' '*(w - i - 1)))
for i in reversed(range(0, d)):
lines.append('%s%s%s' % (' '*i, vsum[4], ' '*(w - i - 1)))
lines.append(vsum[8]*(w))
return d, h + 2*more, lines, more
f = expr.function
prettyF = self._print(f)
if f.is_Add: # add parens
prettyF = prettyForm(*prettyF.parens())
H = prettyF.height() + 2
# \sum \sum \sum ...
first = True
max_upper = 0
sign_height = 0
for lim in expr.limits:
if len(lim) == 3:
prettyUpper = self._print(lim[2])
prettyLower = self._print(Equality(lim[0], lim[1]))
elif len(lim) == 2:
prettyUpper = self._print("")
prettyLower = self._print(Equality(lim[0], lim[1]))
elif len(lim) == 1:
prettyUpper = self._print("")
prettyLower = self._print(lim[0])
max_upper = max(max_upper, prettyUpper.height())
# Create sum sign based on the height of the argument
d, h, slines, adjustment = asum(
H, prettyLower.width(), prettyUpper.width(), ascii_mode)
prettySign = stringPict('')
prettySign = prettyForm(*prettySign.stack(*slines))
if first:
sign_height = prettySign.height()
prettySign = prettyForm(*prettySign.above(prettyUpper))
prettySign = prettyForm(*prettySign.below(prettyLower))
if first:
# change F baseline so it centers on the sign
prettyF.baseline -= d - (prettyF.height()//2 -
prettyF.baseline) - adjustment
first = False
# put padding to the right
pad = stringPict('')
pad = prettyForm(*pad.stack(*[' ']*h))
prettySign = prettyForm(*prettySign.right(pad))
# put the present prettyF to the right
prettyF = prettyForm(*prettySign.right(prettyF))
prettyF.baseline = max_upper + sign_height//2
prettyF.binding = prettyForm.MUL
return prettyF
def _print_Limit(self, l):
e, z, z0, dir = l.args
E = self._print(e)
if precedence(e) <= PRECEDENCE["Mul"]:
E = prettyForm(*E.parens('(', ')'))
Lim = prettyForm('lim')
LimArg = self._print(z)
if self._use_unicode:
LimArg = prettyForm(*LimArg.right(u'\N{BOX DRAWINGS LIGHT HORIZONTAL}\N{RIGHTWARDS ARROW}'))
else:
LimArg = prettyForm(*LimArg.right('->'))
LimArg = prettyForm(*LimArg.right(self._print(z0)))
if str(dir) == '+-' or z0 in (S.Infinity, S.NegativeInfinity):
dir = ""
else:
if self._use_unicode:
dir = u'\N{SUPERSCRIPT PLUS SIGN}' if str(dir) == "+" else u'\N{SUPERSCRIPT MINUS}'
LimArg = prettyForm(*LimArg.right(self._print(dir)))
Lim = prettyForm(*Lim.below(LimArg))
Lim = prettyForm(*Lim.right(E), binding=prettyForm.MUL)
return Lim
def _print_matrix_contents(self, e):
"""
This method factors out what is essentially grid printing.
"""
M = e # matrix
Ms = {} # i,j -> pretty(M[i,j])
for i in range(M.rows):
for j in range(M.cols):
Ms[i, j] = self._print(M[i, j])
# h- and v- spacers
hsep = 2
vsep = 1
# max width for columns
maxw = [-1] * M.cols
for j in range(M.cols):
maxw[j] = max([Ms[i, j].width() for i in range(M.rows)] or [0])
# drawing result
D = None
for i in range(M.rows):
D_row = None
for j in range(M.cols):
s = Ms[i, j]
# reshape s to maxw
# XXX this should be generalized, and go to stringPict.reshape ?
assert s.width() <= maxw[j]
# hcenter it, +0.5 to the right 2
# ( it's better to align formula starts for say 0 and r )
# XXX this is not good in all cases -- maybe introduce vbaseline?
wdelta = maxw[j] - s.width()
wleft = wdelta // 2
wright = wdelta - wleft
s = prettyForm(*s.right(' '*wright))
s = prettyForm(*s.left(' '*wleft))
# we don't need vcenter cells -- this is automatically done in
# a pretty way because when their baselines are taking into
# account in .right()
if D_row is None:
D_row = s # first box in a row
continue
D_row = prettyForm(*D_row.right(' '*hsep)) # h-spacer
D_row = prettyForm(*D_row.right(s))
if D is None:
D = D_row # first row in a picture
continue
# v-spacer
for _ in range(vsep):
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
if D is None:
D = prettyForm('') # Empty Matrix
return D
def _print_MatrixBase(self, e):
D = self._print_matrix_contents(e)
D.baseline = D.height()//2
D = prettyForm(*D.parens('[', ']'))
return D
_print_ImmutableMatrix = _print_MatrixBase
_print_Matrix = _print_MatrixBase
def _print_TensorProduct(self, expr):
# This should somehow share the code with _print_WedgeProduct:
circled_times = "\u2297"
return self._print_seq(expr.args, None, None, circled_times,
parenthesize=lambda x: precedence_traditional(x) <= PRECEDENCE["Mul"])
def _print_WedgeProduct(self, expr):
# This should somehow share the code with _print_TensorProduct:
wedge_symbol = u"\u2227"
return self._print_seq(expr.args, None, None, wedge_symbol,
parenthesize=lambda x: precedence_traditional(x) <= PRECEDENCE["Mul"])
def _print_Trace(self, e):
D = self._print(e.arg)
D = prettyForm(*D.parens('(',')'))
D.baseline = D.height()//2
D = prettyForm(*D.left('\n'*(0) + 'tr'))
return D
def _print_MatrixElement(self, expr):
from sympy.matrices import MatrixSymbol
from sympy import Symbol
if (isinstance(expr.parent, MatrixSymbol)
and expr.i.is_number and expr.j.is_number):
return self._print(
Symbol(expr.parent.name + '_%d%d' % (expr.i, expr.j)))
else:
prettyFunc = self._print(expr.parent)
prettyFunc = prettyForm(*prettyFunc.parens())
prettyIndices = self._print_seq((expr.i, expr.j), delimiter=', '
).parens(left='[', right=']')[0]
pform = prettyForm(binding=prettyForm.FUNC,
*stringPict.next(prettyFunc, prettyIndices))
# store pform parts so it can be reassembled e.g. when powered
pform.prettyFunc = prettyFunc
pform.prettyArgs = prettyIndices
return pform
def _print_MatrixSlice(self, m):
# XXX works only for applied functions
prettyFunc = self._print(m.parent)
def ppslice(x):
x = list(x)
if x[2] == 1:
del x[2]
if x[1] == x[0] + 1:
del x[1]
if x[0] == 0:
x[0] = ''
return prettyForm(*self._print_seq(x, delimiter=':'))
prettyArgs = self._print_seq((ppslice(m.rowslice),
ppslice(m.colslice)), delimiter=', ').parens(left='[', right=']')[0]
pform = prettyForm(
binding=prettyForm.FUNC, *stringPict.next(prettyFunc, prettyArgs))
# store pform parts so it can be reassembled e.g. when powered
pform.prettyFunc = prettyFunc
pform.prettyArgs = prettyArgs
return pform
def _print_Transpose(self, expr):
pform = self._print(expr.arg)
from sympy.matrices import MatrixSymbol
if not isinstance(expr.arg, MatrixSymbol):
pform = prettyForm(*pform.parens())
pform = pform**(prettyForm('T'))
return pform
def _print_Adjoint(self, expr):
pform = self._print(expr.arg)
if self._use_unicode:
dag = prettyForm(u'\N{DAGGER}')
else:
dag = prettyForm('+')
from sympy.matrices import MatrixSymbol
if not isinstance(expr.arg, MatrixSymbol):
pform = prettyForm(*pform.parens())
pform = pform**dag
return pform
def _print_BlockMatrix(self, B):
if B.blocks.shape == (1, 1):
return self._print(B.blocks[0, 0])
return self._print(B.blocks)
def _print_MatAdd(self, expr):
s = None
for item in expr.args:
pform = self._print(item)
if s is None:
s = pform # First element
else:
coeff = item.as_coeff_mmul()[0]
if _coeff_isneg(S(coeff)):
s = prettyForm(*stringPict.next(s, ' '))
pform = self._print(item)
else:
s = prettyForm(*stringPict.next(s, ' + '))
s = prettyForm(*stringPict.next(s, pform))
return s
def _print_MatMul(self, expr):
args = list(expr.args)
from sympy import Add, MatAdd, HadamardProduct, KroneckerProduct
for i, a in enumerate(args):
if (isinstance(a, (Add, MatAdd, HadamardProduct, KroneckerProduct))
and len(expr.args) > 1):
args[i] = prettyForm(*self._print(a).parens())
else:
args[i] = self._print(a)
return prettyForm.__mul__(*args)
def _print_DotProduct(self, expr):
args = list(expr.args)
for i, a in enumerate(args):
args[i] = self._print(a)
return prettyForm.__mul__(*args)
def _print_MatPow(self, expr):
pform = self._print(expr.base)
from sympy.matrices import MatrixSymbol
if not isinstance(expr.base, MatrixSymbol):
pform = prettyForm(*pform.parens())
pform = pform**(self._print(expr.exp))
return pform
def _print_HadamardProduct(self, expr):
from sympy import MatAdd, MatMul
if self._use_unicode:
delim = pretty_atom('Ring')
else:
delim = '.*'
return self._print_seq(expr.args, None, None, delim,
parenthesize=lambda x: isinstance(x, (MatAdd, MatMul)))
def _print_KroneckerProduct(self, expr):
from sympy import MatAdd, MatMul
if self._use_unicode:
delim = u' \N{N-ARY CIRCLED TIMES OPERATOR} '
else:
delim = ' x '
return self._print_seq(expr.args, None, None, delim,
parenthesize=lambda x: isinstance(x, (MatAdd, MatMul)))
_print_MatrixSymbol = _print_Symbol
def _print_FunctionMatrix(self, X):
D = self._print(X.lamda.expr)
D = prettyForm(*D.parens('[', ']'))
return D
def _print_BasisDependent(self, expr):
from sympy.vector import Vector
if not self._use_unicode:
raise NotImplementedError("ASCII pretty printing of BasisDependent is not implemented")
if expr == expr.zero:
return prettyForm(expr.zero._pretty_form)
o1 = []
vectstrs = []
if isinstance(expr, Vector):
items = expr.separate().items()
else:
items = [(0, expr)]
for system, vect in items:
inneritems = list(vect.components.items())
inneritems.sort(key = lambda x: x[0].__str__())
for k, v in inneritems:
#if the coef of the basis vector is 1
#we skip the 1
if v == 1:
o1.append(u"" +
k._pretty_form)
#Same for -1
elif v == -1:
o1.append(u"(-1) " +
k._pretty_form)
#For a general expr
else:
#We always wrap the measure numbers in
#parentheses
arg_str = self._print(
v).parens()[0]
o1.append(arg_str + ' ' + k._pretty_form)
vectstrs.append(k._pretty_form)
#outstr = u("").join(o1)
if o1[0].startswith(u" + "):
o1[0] = o1[0][3:]
elif o1[0].startswith(" "):
o1[0] = o1[0][1:]
#Fixing the newlines
lengths = []
strs = ['']
flag = []
for i, partstr in enumerate(o1):
flag.append(0)
# XXX: What is this hack?
if '\n' in partstr:
tempstr = partstr
tempstr = tempstr.replace(vectstrs[i], '')
if u'\N{right parenthesis extension}' in tempstr: # If scalar is a fraction
for paren in range(len(tempstr)):
flag[i] = 1
if tempstr[paren] == u'\N{right parenthesis extension}':
tempstr = tempstr[:paren] + u'\N{right parenthesis extension}'\
+ ' ' + vectstrs[i] + tempstr[paren + 1:]
break
elif u'\N{RIGHT PARENTHESIS LOWER HOOK}' in tempstr:
flag[i] = 1
tempstr = tempstr.replace(u'\N{RIGHT PARENTHESIS LOWER HOOK}',
u'\N{RIGHT PARENTHESIS LOWER HOOK}'
+ ' ' + vectstrs[i])
else:
tempstr = tempstr.replace(u'\N{RIGHT PARENTHESIS UPPER HOOK}',
u'\N{RIGHT PARENTHESIS UPPER HOOK}'
+ ' ' + vectstrs[i])
o1[i] = tempstr
o1 = [x.split('\n') for x in o1]
n_newlines = max([len(x) for x in o1]) # Width of part in its pretty form
if 1 in flag: # If there was a fractional scalar
for i, parts in enumerate(o1):
if len(parts) == 1: # If part has no newline
parts.insert(0, ' ' * (len(parts[0])))
flag[i] = 1
for i, parts in enumerate(o1):
lengths.append(len(parts[flag[i]]))
for j in range(n_newlines):
if j+1 <= len(parts):
if j >= len(strs):
strs.append(' ' * (sum(lengths[:-1]) +
3*(len(lengths)-1)))
if j == flag[i]:
strs[flag[i]] += parts[flag[i]] + ' + '
else:
strs[j] += parts[j] + ' '*(lengths[-1] -
len(parts[j])+
3)
else:
if j >= len(strs):
strs.append(' ' * (sum(lengths[:-1]) +
3*(len(lengths)-1)))
strs[j] += ' '*(lengths[-1]+3)
return prettyForm(u'\n'.join([s[:-3] for s in strs]))
def _print_NDimArray(self, expr):
from sympy import ImmutableMatrix
if expr.rank() == 0:
return self._print(expr[()])
level_str = [[]] + [[] for i in range(expr.rank())]
shape_ranges = [list(range(i)) for i in expr.shape]
for outer_i in itertools.product(*shape_ranges):
level_str[-1].append(expr[outer_i])
even = True
for back_outer_i in range(expr.rank()-1, -1, -1):
if len(level_str[back_outer_i+1]) < expr.shape[back_outer_i]:
break
if even:
level_str[back_outer_i].append(level_str[back_outer_i+1])
else:
level_str[back_outer_i].append(ImmutableMatrix(level_str[back_outer_i+1]))
if len(level_str[back_outer_i + 1]) == 1:
level_str[back_outer_i][-1] = ImmutableMatrix([[level_str[back_outer_i][-1]]])
even = not even
level_str[back_outer_i+1] = []
out_expr = level_str[0][0]
if expr.rank() % 2 == 1:
out_expr = ImmutableMatrix([out_expr])
return self._print(out_expr)
_print_ImmutableDenseNDimArray = _print_NDimArray
_print_ImmutableSparseNDimArray = _print_NDimArray
_print_MutableDenseNDimArray = _print_NDimArray
_print_MutableSparseNDimArray = _print_NDimArray
def _printer_tensor_indices(self, name, indices, index_map={}):
center = stringPict(name)
top = stringPict(" "*center.width())
bot = stringPict(" "*center.width())
no_top = True
no_bot = True
last_valence = None
prev_map = None
for i, index in enumerate(indices):
indpic = self._print(index.args[0])
if ((index in index_map) or prev_map) and last_valence == index.is_up:
if index.is_up:
top = prettyForm(*stringPict.next(top, ","))
else:
bot = prettyForm(*stringPict.next(bot, ","))
if index in index_map:
indpic = prettyForm(*stringPict.next(indpic, "="))
indpic = prettyForm(*stringPict.next(indpic, self._print(index_map[index])))
prev_map = True
else:
prev_map = False
if index.is_up:
no_top = False
top = stringPict(*top.right(indpic))
center = stringPict(*center.right(" "*indpic.width()))
bot = stringPict(*bot.right(" "*indpic.width()))
else:
no_bot = False
bot = stringPict(*bot.right(indpic))
center = stringPict(*center.right(" "*indpic.width()))
top = stringPict(*top.right(" "*indpic.width()))
last_valence = index.is_up
pict = prettyForm(*center.above(top))
pict = prettyForm(*pict.below(bot))
return pict
def _print_Tensor(self, expr):
name = expr.args[0].name
indices = expr.get_indices()
return self._printer_tensor_indices(name, indices)
def _print_TensorElement(self, expr):
name = expr.expr.args[0].name
indices = expr.expr.get_indices()
index_map = expr.index_map
return self._printer_tensor_indices(name, indices, index_map)
def _print_TensMul(self, expr):
sign, args = expr._get_args_for_traditional_printer()
args = [
prettyForm(*self._print(i).parens()) if
precedence_traditional(i) < PRECEDENCE["Mul"] else self._print(i)
for i in args
]
pform = prettyForm.__mul__(*args)
if sign:
return prettyForm(*pform.left(sign))
else:
return pform
def _print_TensAdd(self, expr):
args = [
prettyForm(*self._print(i).parens()) if
precedence_traditional(i) < PRECEDENCE["Mul"] else self._print(i)
for i in expr.args
]
return prettyForm.__add__(*args)
def _print_TensorIndex(self, expr):
sym = expr.args[0]
if not expr.is_up:
sym = -sym
return self._print(sym)
def _print_PartialDerivative(self, deriv):
if self._use_unicode:
deriv_symbol = U('PARTIAL DIFFERENTIAL')
else:
deriv_symbol = r'd'
x = None
for variable in reversed(deriv.variables):
s = self._print(variable)
ds = prettyForm(*s.left(deriv_symbol))
if x is None:
x = ds
else:
x = prettyForm(*x.right(' '))
x = prettyForm(*x.right(ds))
f = prettyForm(
binding=prettyForm.FUNC, *self._print(deriv.expr).parens())
pform = prettyForm(deriv_symbol)
pform = prettyForm(*pform.below(stringPict.LINE, x))
pform.baseline = pform.baseline + 1
pform = prettyForm(*stringPict.next(pform, f))
pform.binding = prettyForm.MUL
return pform
def _print_Piecewise(self, pexpr):
P = {}
for n, ec in enumerate(pexpr.args):
P[n, 0] = self._print(ec.expr)
if ec.cond == True:
P[n, 1] = prettyForm('otherwise')
else:
P[n, 1] = prettyForm(
*prettyForm('for ').right(self._print(ec.cond)))
hsep = 2
vsep = 1
len_args = len(pexpr.args)
# max widths
maxw = [max([P[i, j].width() for i in range(len_args)])
for j in range(2)]
# FIXME: Refactor this code and matrix into some tabular environment.
# drawing result
D = None
for i in range(len_args):
D_row = None
for j in range(2):
p = P[i, j]
assert p.width() <= maxw[j]
wdelta = maxw[j] - p.width()
wleft = wdelta // 2
wright = wdelta - wleft
p = prettyForm(*p.right(' '*wright))
p = prettyForm(*p.left(' '*wleft))
if D_row is None:
D_row = p
continue
D_row = prettyForm(*D_row.right(' '*hsep)) # h-spacer
D_row = prettyForm(*D_row.right(p))
if D is None:
D = D_row # first row in a picture
continue
# v-spacer
for _ in range(vsep):
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
D = prettyForm(*D.parens('{', ''))
D.baseline = D.height()//2
D.binding = prettyForm.OPEN
return D
def _print_ITE(self, ite):
from sympy.functions.elementary.piecewise import Piecewise
return self._print(ite.rewrite(Piecewise))
def _hprint_vec(self, v):
D = None
for a in v:
p = a
if D is None:
D = p
else:
D = prettyForm(*D.right(', '))
D = prettyForm(*D.right(p))
if D is None:
D = stringPict(' ')
return D
def _hprint_vseparator(self, p1, p2):
tmp = prettyForm(*p1.right(p2))
sep = stringPict(vobj('|', tmp.height()), baseline=tmp.baseline)
return prettyForm(*p1.right(sep, p2))
def _print_hyper(self, e):
# FIXME refactor Matrix, Piecewise, and this into a tabular environment
ap = [self._print(a) for a in e.ap]
bq = [self._print(b) for b in e.bq]
P = self._print(e.argument)
P.baseline = P.height()//2
# Drawing result - first create the ap, bq vectors
D = None
for v in [ap, bq]:
D_row = self._hprint_vec(v)
if D is None:
D = D_row # first row in a picture
else:
D = prettyForm(*D.below(' '))
D = prettyForm(*D.below(D_row))
# make sure that the argument `z' is centred vertically
D.baseline = D.height()//2
# insert horizontal separator
P = prettyForm(*P.left(' '))
D = prettyForm(*D.right(' '))
# insert separating `|`
D = self._hprint_vseparator(D, P)
# add parens
D = prettyForm(*D.parens('(', ')'))
# create the F symbol
above = D.height()//2 - 1
below = D.height() - above - 1
sz, t, b, add, img = annotated('F')
F = prettyForm('\n' * (above - t) + img + '\n' * (below - b),
baseline=above + sz)
add = (sz + 1)//2
F = prettyForm(*F.left(self._print(len(e.ap))))
F = prettyForm(*F.right(self._print(len(e.bq))))
F.baseline = above + add
D = prettyForm(*F.right(' ', D))
return D
def _print_meijerg(self, e):
# FIXME refactor Matrix, Piecewise, and this into a tabular environment
v = {}
v[(0, 0)] = [self._print(a) for a in e.an]
v[(0, 1)] = [self._print(a) for a in e.aother]
v[(1, 0)] = [self._print(b) for b in e.bm]
v[(1, 1)] = [self._print(b) for b in e.bother]
P = self._print(e.argument)
P.baseline = P.height()//2
vp = {}
for idx in v:
vp[idx] = self._hprint_vec(v[idx])
for i in range(2):
maxw = max(vp[(0, i)].width(), vp[(1, i)].width())
for j in range(2):
s = vp[(j, i)]
left = (maxw - s.width()) // 2
right = maxw - left - s.width()
s = prettyForm(*s.left(' ' * left))
s = prettyForm(*s.right(' ' * right))
vp[(j, i)] = s
D1 = prettyForm(*vp[(0, 0)].right(' ', vp[(0, 1)]))
D1 = prettyForm(*D1.below(' '))
D2 = prettyForm(*vp[(1, 0)].right(' ', vp[(1, 1)]))
D = prettyForm(*D1.below(D2))
# make sure that the argument `z' is centred vertically
D.baseline = D.height()//2
# insert horizontal separator
P = prettyForm(*P.left(' '))
D = prettyForm(*D.right(' '))
# insert separating `|`
D = self._hprint_vseparator(D, P)
# add parens
D = prettyForm(*D.parens('(', ')'))
# create the G symbol
above = D.height()//2 - 1
below = D.height() - above - 1
sz, t, b, add, img = annotated('G')
F = prettyForm('\n' * (above - t) + img + '\n' * (below - b),
baseline=above + sz)
pp = self._print(len(e.ap))
pq = self._print(len(e.bq))
pm = self._print(len(e.bm))
pn = self._print(len(e.an))
def adjust(p1, p2):
diff = p1.width() - p2.width()
if diff == 0:
return p1, p2
elif diff > 0:
return p1, prettyForm(*p2.left(' '*diff))
else:
return prettyForm(*p1.left(' '*-diff)), p2
pp, pm = adjust(pp, pm)
pq, pn = adjust(pq, pn)
pu = prettyForm(*pm.right(', ', pn))
pl = prettyForm(*pp.right(', ', pq))
ht = F.baseline - above - 2
if ht > 0:
pu = prettyForm(*pu.below('\n'*ht))
p = prettyForm(*pu.below(pl))
F.baseline = above
F = prettyForm(*F.right(p))
F.baseline = above + add
D = prettyForm(*F.right(' ', D))
return D
def _print_ExpBase(self, e):
# TODO should exp_polar be printed differently?
# what about exp_polar(0), exp_polar(1)?
base = prettyForm(pretty_atom('Exp1', 'e'))
return base ** self._print(e.args[0])
def _print_Function(self, e, sort=False, func_name=None):
# optional argument func_name for supplying custom names
# XXX works only for applied functions
func = e.func
args = e.args
if sort:
args = sorted(args, key=default_sort_key)
if not func_name:
func_name = func.__name__
prettyFunc = self._print(Symbol(func_name))
prettyArgs = prettyForm(*self._print_seq(args).parens())
pform = prettyForm(
binding=prettyForm.FUNC, *stringPict.next(prettyFunc, prettyArgs))
# store pform parts so it can be reassembled e.g. when powered
pform.prettyFunc = prettyFunc
pform.prettyArgs = prettyArgs
return pform
@property
def _special_function_classes(self):
from sympy.functions.special.tensor_functions import KroneckerDelta
from sympy.functions.special.gamma_functions import gamma, lowergamma
from sympy.functions.special.beta_functions import beta
from sympy.functions.special.delta_functions import DiracDelta
from sympy.functions.special.error_functions import Chi
return {KroneckerDelta: [greek_unicode['delta'], 'delta'],
gamma: [greek_unicode['Gamma'], 'Gamma'],
lowergamma: [greek_unicode['gamma'], 'gamma'],
beta: [greek_unicode['Beta'], 'B'],
DiracDelta: [greek_unicode['delta'], 'delta'],
Chi: ['Chi', 'Chi']}
def _print_FunctionClass(self, expr):
for cls in self._special_function_classes:
if issubclass(expr, cls) and expr.__name__ == cls.__name__:
if self._use_unicode:
return prettyForm(self._special_function_classes[cls][0])
else:
return prettyForm(self._special_function_classes[cls][1])
func_name = expr.__name__
return prettyForm(pretty_symbol(func_name))
def _print_GeometryEntity(self, expr):
# GeometryEntity is based on Tuple but should not print like a Tuple
return self.emptyPrinter(expr)
def _print_Lambda(self, e):
vars, expr = e.args
if self._use_unicode:
arrow = u" \N{RIGHTWARDS ARROW FROM BAR} "
else:
arrow = " -> "
if len(vars) == 1:
var_form = self._print(vars[0])
else:
var_form = self._print(tuple(vars))
return prettyForm(*stringPict.next(var_form, arrow, self._print(expr)), binding=8)
def _print_Order(self, expr):
pform = self._print(expr.expr)
if (expr.point and any(p != S.Zero for p in expr.point)) or \
len(expr.variables) > 1:
pform = prettyForm(*pform.right("; "))
if len(expr.variables) > 1:
pform = prettyForm(*pform.right(self._print(expr.variables)))
elif len(expr.variables):
pform = prettyForm(*pform.right(self._print(expr.variables[0])))
if self._use_unicode:
pform = prettyForm(*pform.right(u" \N{RIGHTWARDS ARROW} "))
else:
pform = prettyForm(*pform.right(" -> "))
if len(expr.point) > 1:
pform = prettyForm(*pform.right(self._print(expr.point)))
else:
pform = prettyForm(*pform.right(self._print(expr.point[0])))
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left("O"))
return pform
def _print_SingularityFunction(self, e):
if self._use_unicode:
shift = self._print(e.args[0]-e.args[1])
n = self._print(e.args[2])
base = prettyForm("<")
base = prettyForm(*base.right(shift))
base = prettyForm(*base.right(">"))
pform = base**n
return pform
else:
n = self._print(e.args[2])
shift = self._print(e.args[0]-e.args[1])
base = self._print_seq(shift, "<", ">", ' ')
return base**n
def _print_beta(self, e):
func_name = greek_unicode['Beta'] if self._use_unicode else 'B'
return self._print_Function(e, func_name=func_name)
def _print_gamma(self, e):
func_name = greek_unicode['Gamma'] if self._use_unicode else 'Gamma'
return self._print_Function(e, func_name=func_name)
def _print_uppergamma(self, e):
func_name = greek_unicode['Gamma'] if self._use_unicode else 'Gamma'
return self._print_Function(e, func_name=func_name)
def _print_lowergamma(self, e):
func_name = greek_unicode['gamma'] if self._use_unicode else 'lowergamma'
return self._print_Function(e, func_name=func_name)
def _print_DiracDelta(self, e):
if self._use_unicode:
if len(e.args) == 2:
a = prettyForm(greek_unicode['delta'])
b = self._print(e.args[1])
b = prettyForm(*b.parens())
c = self._print(e.args[0])
c = prettyForm(*c.parens())
pform = a**b
pform = prettyForm(*pform.right(' '))
pform = prettyForm(*pform.right(c))
return pform
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left(greek_unicode['delta']))
return pform
else:
return self._print_Function(e)
def _print_expint(self, e):
from sympy import Function
if e.args[0].is_Integer and self._use_unicode:
return self._print_Function(Function('E_%s' % e.args[0])(e.args[1]))
return self._print_Function(e)
def _print_Chi(self, e):
# This needs a special case since otherwise it comes out as greek
# letter chi...
prettyFunc = prettyForm("Chi")
prettyArgs = prettyForm(*self._print_seq(e.args).parens())
pform = prettyForm(
binding=prettyForm.FUNC, *stringPict.next(prettyFunc, prettyArgs))
# store pform parts so it can be reassembled e.g. when powered
pform.prettyFunc = prettyFunc
pform.prettyArgs = prettyArgs
return pform
def _print_elliptic_e(self, e):
pforma0 = self._print(e.args[0])
if len(e.args) == 1:
pform = pforma0
else:
pforma1 = self._print(e.args[1])
pform = self._hprint_vseparator(pforma0, pforma1)
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left('E'))
return pform
def _print_elliptic_k(self, e):
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left('K'))
return pform
def _print_elliptic_f(self, e):
pforma0 = self._print(e.args[0])
pforma1 = self._print(e.args[1])
pform = self._hprint_vseparator(pforma0, pforma1)
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left('F'))
return pform
def _print_elliptic_pi(self, e):
name = greek_unicode['Pi'] if self._use_unicode else 'Pi'
pforma0 = self._print(e.args[0])
pforma1 = self._print(e.args[1])
if len(e.args) == 2:
pform = self._hprint_vseparator(pforma0, pforma1)
else:
pforma2 = self._print(e.args[2])
pforma = self._hprint_vseparator(pforma1, pforma2)
pforma = prettyForm(*pforma.left('; '))
pform = prettyForm(*pforma.left(pforma0))
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left(name))
return pform
def _print_GoldenRatio(self, expr):
if self._use_unicode:
return prettyForm(pretty_symbol('phi'))
return self._print(Symbol("GoldenRatio"))
def _print_EulerGamma(self, expr):
if self._use_unicode:
return prettyForm(pretty_symbol('gamma'))
return self._print(Symbol("EulerGamma"))
def _print_Mod(self, expr):
pform = self._print(expr.args[0])
if pform.binding > prettyForm.MUL:
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.right(' mod '))
pform = prettyForm(*pform.right(self._print(expr.args[1])))
pform.binding = prettyForm.OPEN
return pform
def _print_Add(self, expr, order=None):
if self.order == 'none':
terms = list(expr.args)
else:
terms = self._as_ordered_terms(expr, order=order)
pforms, indices = [], []
def pretty_negative(pform, index):
"""Prepend a minus sign to a pretty form. """
#TODO: Move this code to prettyForm
if index == 0:
if pform.height() > 1:
pform_neg = '- '
else:
pform_neg = '-'
else:
pform_neg = ' - '
if (pform.binding > prettyForm.NEG
or pform.binding == prettyForm.ADD):
p = stringPict(*pform.parens())
else:
p = pform
p = stringPict.next(pform_neg, p)
# Lower the binding to NEG, even if it was higher. Otherwise, it
# will print as a + ( - (b)), instead of a - (b).
return prettyForm(binding=prettyForm.NEG, *p)
for i, term in enumerate(terms):
if term.is_Mul and _coeff_isneg(term):
coeff, other = term.as_coeff_mul(rational=False)
pform = self._print(Mul(-coeff, *other, evaluate=False))
pforms.append(pretty_negative(pform, i))
elif term.is_Rational and term.q > 1:
pforms.append(None)
indices.append(i)
elif term.is_Number and term < 0:
pform = self._print(-term)
pforms.append(pretty_negative(pform, i))
elif term.is_Relational:
pforms.append(prettyForm(*self._print(term).parens()))
else:
pforms.append(self._print(term))
if indices:
large = True
for pform in pforms:
if pform is not None and pform.height() > 1:
break
else:
large = False
for i in indices:
term, negative = terms[i], False
if term < 0:
term, negative = -term, True
if large:
pform = prettyForm(str(term.p))/prettyForm(str(term.q))
else:
pform = self._print(term)
if negative:
pform = pretty_negative(pform, i)
pforms[i] = pform
return prettyForm.__add__(*pforms)
def _print_Mul(self, product):
from sympy.physics.units import Quantity
a = [] # items in the numerator
b = [] # items that are in the denominator (if any)
if self.order not in ('old', 'none'):
args = product.as_ordered_factors()
else:
args = list(product.args)
# If quantities are present append them at the back
args = sorted(args, key=lambda x: isinstance(x, Quantity) or
(isinstance(x, Pow) and isinstance(x.base, Quantity)))
# Gather terms for numerator/denominator
for item in args:
if item.is_commutative and item.is_Pow and item.exp.is_Rational and item.exp.is_negative:
if item.exp != -1:
b.append(Pow(item.base, -item.exp, evaluate=False))
else:
b.append(Pow(item.base, -item.exp))
elif item.is_Rational and item is not S.Infinity:
if item.p != 1:
a.append( Rational(item.p) )
if item.q != 1:
b.append( Rational(item.q) )
else:
a.append(item)
from sympy import Integral, Piecewise, Product, Sum
# Convert to pretty forms. Add parens to Add instances if there
# is more than one term in the numer/denom
for i in range(0, len(a)):
if (a[i].is_Add and len(a) > 1) or (i != len(a) - 1 and
isinstance(a[i], (Integral, Piecewise, Product, Sum))):
a[i] = prettyForm(*self._print(a[i]).parens())
elif a[i].is_Relational:
a[i] = prettyForm(*self._print(a[i]).parens())
else:
a[i] = self._print(a[i])
for i in range(0, len(b)):
if (b[i].is_Add and len(b) > 1) or (i != len(b) - 1 and
isinstance(b[i], (Integral, Piecewise, Product, Sum))):
b[i] = prettyForm(*self._print(b[i]).parens())
else:
b[i] = self._print(b[i])
# Construct a pretty form
if len(b) == 0:
return prettyForm.__mul__(*a)
else:
if len(a) == 0:
a.append( self._print(S.One) )
return prettyForm.__mul__(*a)/prettyForm.__mul__(*b)
# A helper function for _print_Pow to print x**(1/n)
def _print_nth_root(self, base, expt):
bpretty = self._print(base)
# In very simple cases, use a single-char root sign
if (self._settings['use_unicode_sqrt_char'] and self._use_unicode
and expt is S.Half and bpretty.height() == 1
and (bpretty.width() == 1
or (base.is_Integer and base.is_nonnegative))):
return prettyForm(*bpretty.left(u'\N{SQUARE ROOT}'))
# Construct root sign, start with the \/ shape
_zZ = xobj('/', 1)
rootsign = xobj('\\', 1) + _zZ
# Make exponent number to put above it
if isinstance(expt, Rational):
exp = str(expt.q)
if exp == '2':
exp = ''
else:
exp = str(expt.args[0])
exp = exp.ljust(2)
if len(exp) > 2:
rootsign = ' '*(len(exp) - 2) + rootsign
# Stack the exponent
rootsign = stringPict(exp + '\n' + rootsign)
rootsign.baseline = 0
# Diagonal: length is one less than height of base
linelength = bpretty.height() - 1
diagonal = stringPict('\n'.join(
' '*(linelength - i - 1) + _zZ + ' '*i
for i in range(linelength)
))
# Put baseline just below lowest line: next to exp
diagonal.baseline = linelength - 1
# Make the root symbol
rootsign = prettyForm(*rootsign.right(diagonal))
# Det the baseline to match contents to fix the height
# but if the height of bpretty is one, the rootsign must be one higher
rootsign.baseline = max(1, bpretty.baseline)
#build result
s = prettyForm(hobj('_', 2 + bpretty.width()))
s = prettyForm(*bpretty.above(s))
s = prettyForm(*s.left(rootsign))
return s
def _print_Pow(self, power):
from sympy.simplify.simplify import fraction
b, e = power.as_base_exp()
if power.is_commutative:
if e is S.NegativeOne:
return prettyForm("1")/self._print(b)
n, d = fraction(e)
if n is S.One and d.is_Atom and not e.is_Integer:
return self._print_nth_root(b, e)
if e.is_Rational and e < 0:
return prettyForm("1")/self._print(Pow(b, -e, evaluate=False))
if b.is_Relational:
return prettyForm(*self._print(b).parens()).__pow__(self._print(e))
return self._print(b)**self._print(e)
def _print_UnevaluatedExpr(self, expr):
return self._print(expr.args[0])
def __print_numer_denom(self, p, q):
if q == 1:
if p < 0:
return prettyForm(str(p), binding=prettyForm.NEG)
else:
return prettyForm(str(p))
elif abs(p) >= 10 and abs(q) >= 10:
# If more than one digit in numer and denom, print larger fraction
if p < 0:
return prettyForm(str(p), binding=prettyForm.NEG)/prettyForm(str(q))
# Old printing method:
#pform = prettyForm(str(-p))/prettyForm(str(q))
#return prettyForm(binding=prettyForm.NEG, *pform.left('- '))
else:
return prettyForm(str(p))/prettyForm(str(q))
else:
return None
def _print_Rational(self, expr):
result = self.__print_numer_denom(expr.p, expr.q)
if result is not None:
return result
else:
return self.emptyPrinter(expr)
def _print_Fraction(self, expr):
result = self.__print_numer_denom(expr.numerator, expr.denominator)
if result is not None:
return result
else:
return self.emptyPrinter(expr)
def _print_ProductSet(self, p):
if len(p.sets) > 1 and not has_variety(p.sets):
from sympy import Pow
return self._print(Pow(p.sets[0], len(p.sets), evaluate=False))
else:
prod_char = u"\N{MULTIPLICATION SIGN}" if self._use_unicode else 'x'
return self._print_seq(p.sets, None, None, ' %s ' % prod_char,
parenthesize=lambda set: set.is_Union or
set.is_Intersection or set.is_ProductSet)
def _print_FiniteSet(self, s):
items = sorted(s.args, key=default_sort_key)
return self._print_seq(items, '{', '}', ', ' )
def _print_Range(self, s):
if self._use_unicode:
dots = u"\N{HORIZONTAL ELLIPSIS}"
else:
dots = '...'
if s.start.is_infinite:
printset = s.start, dots, s[-1] - s.step, s[-1]
elif s.stop.is_infinite or len(s) > 4:
it = iter(s)
printset = next(it), next(it), dots, s[-1]
else:
printset = tuple(s)
return self._print_seq(printset, '{', '}', ', ' )
def _print_Interval(self, i):
if i.start == i.end:
return self._print_seq(i.args[:1], '{', '}')
else:
if i.left_open:
left = '('
else:
left = '['
if i.right_open:
right = ')'
else:
right = ']'
return self._print_seq(i.args[:2], left, right)
def _print_AccumulationBounds(self, i):
left = '<'
right = '>'
return self._print_seq(i.args[:2], left, right)
def _print_Intersection(self, u):
delimiter = ' %s ' % pretty_atom('Intersection', 'n')
return self._print_seq(u.args, None, None, delimiter,
parenthesize=lambda set: set.is_ProductSet or
set.is_Union or set.is_Complement)
def _print_Union(self, u):
union_delimiter = ' %s ' % pretty_atom('Union', 'U')
return self._print_seq(u.args, None, None, union_delimiter,
parenthesize=lambda set: set.is_ProductSet or
set.is_Intersection or set.is_Complement)
def _print_SymmetricDifference(self, u):
if not self._use_unicode:
raise NotImplementedError("ASCII pretty printing of SymmetricDifference is not implemented")
sym_delimeter = ' %s ' % pretty_atom('SymmetricDifference')
return self._print_seq(u.args, None, None, sym_delimeter)
def _print_Complement(self, u):
delimiter = r' \ '
return self._print_seq(u.args, None, None, delimiter,
parenthesize=lambda set: set.is_ProductSet or set.is_Intersection
or set.is_Union)
def _print_ImageSet(self, ts):
if self._use_unicode:
inn = u"\N{SMALL ELEMENT OF}"
else:
inn = 'in'
variables = ts.lamda.variables
expr = self._print(ts.lamda.expr)
bar = self._print("|")
sets = [self._print(i) for i in ts.args[1:]]
if len(sets) == 1:
return self._print_seq((expr, bar, variables[0], inn, sets[0]), "{", "}", ' ')
else:
pargs = tuple(j for var, setv in zip(variables, sets) for j in (var, inn, setv, ","))
return self._print_seq((expr, bar) + pargs[:-1], "{", "}", ' ')
def _print_ConditionSet(self, ts):
if self._use_unicode:
inn = u"\N{SMALL ELEMENT OF}"
# using _and because and is a keyword and it is bad practice to
# overwrite them
_and = u"\N{LOGICAL AND}"
else:
inn = 'in'
_and = 'and'
variables = self._print_seq(Tuple(ts.sym))
try:
cond = self._print(ts.condition.as_expr())
except AttributeError:
cond = self._print(ts.condition)
if self._use_unicode:
cond = self._print_seq(cond, "(", ")")
bar = self._print("|")
if ts.base_set is S.UniversalSet:
return self._print_seq((variables, bar, cond), "{", "}", ' ')
base = self._print(ts.base_set)
return self._print_seq((variables, bar, variables, inn,
base, _and, cond), "{", "}", ' ')
def _print_ComplexRegion(self, ts):
if self._use_unicode:
inn = u"\N{SMALL ELEMENT OF}"
else:
inn = 'in'
variables = self._print_seq(ts.variables)
expr = self._print(ts.expr)
bar = self._print("|")
prodsets = self._print(ts.sets)
return self._print_seq((expr, bar, variables, inn, prodsets), "{", "}", ' ')
def _print_Contains(self, e):
var, set = e.args
if self._use_unicode:
el = u" \N{ELEMENT OF} "
return prettyForm(*stringPict.next(self._print(var),
el, self._print(set)), binding=8)
else:
return prettyForm(sstr(e))
def _print_FourierSeries(self, s):
if self._use_unicode:
dots = u"\N{HORIZONTAL ELLIPSIS}"
else:
dots = '...'
return self._print_Add(s.truncate()) + self._print(dots)
def _print_FormalPowerSeries(self, s):
return self._print_Add(s.infinite)
def _print_SetExpr(self, se):
pretty_set = prettyForm(*self._print(se.set).parens())
pretty_name = self._print(Symbol("SetExpr"))
return prettyForm(*pretty_name.right(pretty_set))
def _print_SeqFormula(self, s):
if self._use_unicode:
dots = u"\N{HORIZONTAL ELLIPSIS}"
else:
dots = '...'
if s.start is S.NegativeInfinity:
stop = s.stop
printset = (dots, s.coeff(stop - 3), s.coeff(stop - 2),
s.coeff(stop - 1), s.coeff(stop))
elif s.stop is S.Infinity or s.length > 4:
printset = s[:4]
printset.append(dots)
printset = tuple(printset)
else:
printset = tuple(s)
return self._print_list(printset)
_print_SeqPer = _print_SeqFormula
_print_SeqAdd = _print_SeqFormula
_print_SeqMul = _print_SeqFormula
def _print_seq(self, seq, left=None, right=None, delimiter=', ',
parenthesize=lambda x: False):
s = None
try:
for item in seq:
pform = self._print(item)
if parenthesize(item):
pform = prettyForm(*pform.parens())
if s is None:
# first element
s = pform
else:
s = prettyForm(*stringPict.next(s, delimiter))
s = prettyForm(*stringPict.next(s, pform))
if s is None:
s = stringPict('')
except AttributeError:
s = None
for item in seq:
pform = self.doprint(item)
if parenthesize(item):
pform = prettyForm(*pform.parens())
if s is None:
# first element
s = pform
else :
s = prettyForm(*stringPict.next(s, delimiter))
s = prettyForm(*stringPict.next(s, pform))
if s is None:
s = stringPict('')
s = prettyForm(*s.parens(left, right, ifascii_nougly=True))
return s
def join(self, delimiter, args):
pform = None
for arg in args:
if pform is None:
pform = arg
else:
pform = prettyForm(*pform.right(delimiter))
pform = prettyForm(*pform.right(arg))
if pform is None:
return prettyForm("")
else:
return pform
def _print_list(self, l):
return self._print_seq(l, '[', ']')
def _print_tuple(self, t):
if len(t) == 1:
ptuple = prettyForm(*stringPict.next(self._print(t[0]), ','))
return prettyForm(*ptuple.parens('(', ')', ifascii_nougly=True))
else:
return self._print_seq(t, '(', ')')
def _print_Tuple(self, expr):
return self._print_tuple(expr)
def _print_dict(self, d):
keys = sorted(d.keys(), key=default_sort_key)
items = []
for k in keys:
K = self._print(k)
V = self._print(d[k])
s = prettyForm(*stringPict.next(K, ': ', V))
items.append(s)
return self._print_seq(items, '{', '}')
def _print_Dict(self, d):
return self._print_dict(d)
def _print_set(self, s):
if not s:
return prettyForm('set()')
items = sorted(s, key=default_sort_key)
pretty = self._print_seq(items)
pretty = prettyForm(*pretty.parens('{', '}', ifascii_nougly=True))
return pretty
def _print_frozenset(self, s):
if not s:
return prettyForm('frozenset()')
items = sorted(s, key=default_sort_key)
pretty = self._print_seq(items)
pretty = prettyForm(*pretty.parens('{', '}', ifascii_nougly=True))
pretty = prettyForm(*pretty.parens('(', ')', ifascii_nougly=True))
pretty = prettyForm(*stringPict.next(type(s).__name__, pretty))
return pretty
def _print_PolyRing(self, ring):
return prettyForm(sstr(ring))
def _print_FracField(self, field):
return prettyForm(sstr(field))
def _print_FreeGroupElement(self, elm):
return prettyForm(str(elm))
def _print_PolyElement(self, poly):
return prettyForm(sstr(poly))
def _print_FracElement(self, frac):
return prettyForm(sstr(frac))
def _print_AlgebraicNumber(self, expr):
if expr.is_aliased:
return self._print(expr.as_poly().as_expr())
else:
return self._print(expr.as_expr())
def _print_ComplexRootOf(self, expr):
args = [self._print_Add(expr.expr, order='lex'), expr.index]
pform = prettyForm(*self._print_seq(args).parens())
pform = prettyForm(*pform.left('CRootOf'))
return pform
def _print_RootSum(self, expr):
args = [self._print_Add(expr.expr, order='lex')]
if expr.fun is not S.IdentityFunction:
args.append(self._print(expr.fun))
pform = prettyForm(*self._print_seq(args).parens())
pform = prettyForm(*pform.left('RootSum'))
return pform
def _print_FiniteField(self, expr):
if self._use_unicode:
form = u'\N{DOUBLE-STRUCK CAPITAL Z}_%d'
else:
form = 'GF(%d)'
return prettyForm(pretty_symbol(form % expr.mod))
def _print_IntegerRing(self, expr):
if self._use_unicode:
return prettyForm(u'\N{DOUBLE-STRUCK CAPITAL Z}')
else:
return prettyForm('ZZ')
def _print_RationalField(self, expr):
if self._use_unicode:
return prettyForm(u'\N{DOUBLE-STRUCK CAPITAL Q}')
else:
return prettyForm('QQ')
def _print_RealField(self, domain):
if self._use_unicode:
prefix = u'\N{DOUBLE-STRUCK CAPITAL R}'
else:
prefix = 'RR'
if domain.has_default_precision:
return prettyForm(prefix)
else:
return self._print(pretty_symbol(prefix + "_" + str(domain.precision)))
def _print_ComplexField(self, domain):
if self._use_unicode:
prefix = u'\N{DOUBLE-STRUCK CAPITAL C}'
else:
prefix = 'CC'
if domain.has_default_precision:
return prettyForm(prefix)
else:
return self._print(pretty_symbol(prefix + "_" + str(domain.precision)))
def _print_PolynomialRing(self, expr):
args = list(expr.symbols)
if not expr.order.is_default:
order = prettyForm(*prettyForm("order=").right(self._print(expr.order)))
args.append(order)
pform = self._print_seq(args, '[', ']')
pform = prettyForm(*pform.left(self._print(expr.domain)))
return pform
def _print_FractionField(self, expr):
args = list(expr.symbols)
if not expr.order.is_default:
order = prettyForm(*prettyForm("order=").right(self._print(expr.order)))
args.append(order)
pform = self._print_seq(args, '(', ')')
pform = prettyForm(*pform.left(self._print(expr.domain)))
return pform
def _print_PolynomialRingBase(self, expr):
g = expr.symbols
if str(expr.order) != str(expr.default_order):
g = g + ("order=" + str(expr.order),)
pform = self._print_seq(g, '[', ']')
pform = prettyForm(*pform.left(self._print(expr.domain)))
return pform
def _print_GroebnerBasis(self, basis):
exprs = [ self._print_Add(arg, order=basis.order)
for arg in basis.exprs ]
exprs = prettyForm(*self.join(", ", exprs).parens(left="[", right="]"))
gens = [ self._print(gen) for gen in basis.gens ]
domain = prettyForm(
*prettyForm("domain=").right(self._print(basis.domain)))
order = prettyForm(
*prettyForm("order=").right(self._print(basis.order)))
pform = self.join(", ", [exprs] + gens + [domain, order])
pform = prettyForm(*pform.parens())
pform = prettyForm(*pform.left(basis.__class__.__name__))
return pform
def _print_Subs(self, e):
pform = self._print(e.expr)
pform = prettyForm(*pform.parens())
h = pform.height() if pform.height() > 1 else 2
rvert = stringPict(vobj('|', h), baseline=pform.baseline)
pform = prettyForm(*pform.right(rvert))
b = pform.baseline
pform.baseline = pform.height() - 1
pform = prettyForm(*pform.right(self._print_seq([
self._print_seq((self._print(v[0]), xsym('=='), self._print(v[1])),
delimiter='') for v in zip(e.variables, e.point) ])))
pform.baseline = b
return pform
def _print_euler(self, e):
pform = prettyForm("E")
arg = self._print(e.args[0])
pform_arg = prettyForm(" "*arg.width())
pform_arg = prettyForm(*pform_arg.below(arg))
pform = prettyForm(*pform.right(pform_arg))
if len(e.args) == 1:
return pform
m, x = e.args
# TODO: copy-pasted from _print_Function: can we do better?
prettyFunc = pform
prettyArgs = prettyForm(*self._print_seq([x]).parens())
pform = prettyForm(
binding=prettyForm.FUNC, *stringPict.next(prettyFunc, prettyArgs))
pform.prettyFunc = prettyFunc
pform.prettyArgs = prettyArgs
return pform
def _print_catalan(self, e):
pform = prettyForm("C")
arg = self._print(e.args[0])
pform_arg = prettyForm(" "*arg.width())
pform_arg = prettyForm(*pform_arg.below(arg))
pform = prettyForm(*pform.right(pform_arg))
return pform
def _print_KroneckerDelta(self, e):
pform = self._print(e.args[0])
pform = prettyForm(*pform.right((prettyForm(','))))
pform = prettyForm(*pform.right((self._print(e.args[1]))))
if self._use_unicode:
a = stringPict(pretty_symbol('delta'))
else:
a = stringPict('d')
b = pform
top = stringPict(*b.left(' '*a.width()))
bot = stringPict(*a.right(' '*b.width()))
return prettyForm(binding=prettyForm.POW, *bot.below(top))
def _print_RandomDomain(self, d):
if hasattr(d, 'as_boolean'):
pform = self._print('Domain: ')
pform = prettyForm(*pform.right(self._print(d.as_boolean())))
return pform
elif hasattr(d, 'set'):
pform = self._print('Domain: ')
pform = prettyForm(*pform.right(self._print(d.symbols)))
pform = prettyForm(*pform.right(self._print(' in ')))
pform = prettyForm(*pform.right(self._print(d.set)))
return pform
elif hasattr(d, 'symbols'):
pform = self._print('Domain on ')
pform = prettyForm(*pform.right(self._print(d.symbols)))
return pform
else:
return self._print(None)
def _print_DMP(self, p):
try:
if p.ring is not None:
# TODO incorporate order
return self._print(p.ring.to_sympy(p))
except SympifyError:
pass
return self._print(repr(p))
def _print_DMF(self, p):
return self._print_DMP(p)
def _print_Object(self, object):
return self._print(pretty_symbol(object.name))
def _print_Morphism(self, morphism):
arrow = xsym("-->")
domain = self._print(morphism.domain)
codomain = self._print(morphism.codomain)
tail = domain.right(arrow, codomain)[0]
return prettyForm(tail)
def _print_NamedMorphism(self, morphism):
pretty_name = self._print(pretty_symbol(morphism.name))
pretty_morphism = self._print_Morphism(morphism)
return prettyForm(pretty_name.right(":", pretty_morphism)[0])
def _print_IdentityMorphism(self, morphism):
from sympy.categories import NamedMorphism
return self._print_NamedMorphism(
NamedMorphism(morphism.domain, morphism.codomain, "id"))
def _print_CompositeMorphism(self, morphism):
circle = xsym(".")
# All components of the morphism have names and it is thus
# possible to build the name of the composite.
component_names_list = [pretty_symbol(component.name) for
component in morphism.components]
component_names_list.reverse()
component_names = circle.join(component_names_list) + ":"
pretty_name = self._print(component_names)
pretty_morphism = self._print_Morphism(morphism)
return prettyForm(pretty_name.right(pretty_morphism)[0])
def _print_Category(self, category):
return self._print(pretty_symbol(category.name))
def _print_Diagram(self, diagram):
if not diagram.premises:
# This is an empty diagram.
return self._print(S.EmptySet)
pretty_result = self._print(diagram.premises)
if diagram.conclusions:
results_arrow = " %s " % xsym("==>")
pretty_conclusions = self._print(diagram.conclusions)[0]
pretty_result = pretty_result.right(
results_arrow, pretty_conclusions)
return prettyForm(pretty_result[0])
def _print_DiagramGrid(self, grid):
from sympy.matrices import Matrix
from sympy import Symbol
matrix = Matrix([[grid[i, j] if grid[i, j] else Symbol(" ")
for j in range(grid.width)]
for i in range(grid.height)])
return self._print_matrix_contents(matrix)
def _print_FreeModuleElement(self, m):
# Print as row vector for convenience, for now.
return self._print_seq(m, '[', ']')
def _print_SubModule(self, M):
return self._print_seq(M.gens, '<', '>')
def _print_FreeModule(self, M):
return self._print(M.ring)**self._print(M.rank)
def _print_ModuleImplementedIdeal(self, M):
return self._print_seq([x for [x] in M._module.gens], '<', '>')
def _print_QuotientRing(self, R):
return self._print(R.ring) / self._print(R.base_ideal)
def _print_QuotientRingElement(self, R):
return self._print(R.data) + self._print(R.ring.base_ideal)
def _print_QuotientModuleElement(self, m):
return self._print(m.data) + self._print(m.module.killed_module)
def _print_QuotientModule(self, M):
return self._print(M.base) / self._print(M.killed_module)
def _print_MatrixHomomorphism(self, h):
matrix = self._print(h._sympy_matrix())
matrix.baseline = matrix.height() // 2
pform = prettyForm(*matrix.right(' : ', self._print(h.domain),
' %s> ' % hobj('-', 2), self._print(h.codomain)))
return pform
def _print_BaseScalarField(self, field):
string = field._coord_sys._names[field._index]
return self._print(pretty_symbol(string))
def _print_BaseVectorField(self, field):
s = U('PARTIAL DIFFERENTIAL') + '_' + field._coord_sys._names[field._index]
return self._print(pretty_symbol(s))
def _print_Differential(self, diff):
field = diff._form_field
if hasattr(field, '_coord_sys'):
string = field._coord_sys._names[field._index]
return self._print(u'\N{DOUBLE-STRUCK ITALIC SMALL D} ' + pretty_symbol(string))
else:
pform = self._print(field)
pform = prettyForm(*pform.parens())
return prettyForm(*pform.left(u"\N{DOUBLE-STRUCK ITALIC SMALL D}"))
def _print_Tr(self, p):
#TODO: Handle indices
pform = self._print(p.args[0])
pform = prettyForm(*pform.left('%s(' % (p.__class__.__name__)))
pform = prettyForm(*pform.right(')'))
return pform
def _print_primenu(self, e):
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens())
if self._use_unicode:
pform = prettyForm(*pform.left(greek_unicode['nu']))
else:
pform = prettyForm(*pform.left('nu'))
return pform
def _print_primeomega(self, e):
pform = self._print(e.args[0])
pform = prettyForm(*pform.parens())
if self._use_unicode:
pform = prettyForm(*pform.left(greek_unicode['Omega']))
else:
pform = prettyForm(*pform.left('Omega'))
return pform
def _print_Quantity(self, e):
if e.name.name == 'degree':
pform = self._print(u"\N{DEGREE SIGN}")
return pform
else:
return self.emptyPrinter(e)
def _print_AssignmentBase(self, e):
op = prettyForm(' ' + xsym(e.op) + ' ')
l = self._print(e.lhs)
r = self._print(e.rhs)
pform = prettyForm(*stringPict.next(l, op, r))
return pform
def pretty(expr, **settings):
"""Returns a string containing the prettified form of expr.
For information on keyword arguments see pretty_print function.
"""
pp = PrettyPrinter(settings)
# XXX: this is an ugly hack, but at least it works
use_unicode = pp._settings['use_unicode']
uflag = pretty_use_unicode(use_unicode)
try:
return pp.doprint(expr)
finally:
pretty_use_unicode(uflag)
def pretty_print(expr, wrap_line=True, num_columns=None, use_unicode=None,
full_prec="auto", order=None, use_unicode_sqrt_char=True):
"""Prints expr in pretty form.
pprint is just a shortcut for this function.
Parameters
==========
expr : expression
The expression to print.
wrap_line : bool, optional (default=True)
Line wrapping enabled/disabled.
num_columns : int or None, optional (default=None)
Number of columns before line breaking (default to None which reads
the terminal width), useful when using SymPy without terminal.
use_unicode : bool or None, optional (default=None)
Use unicode characters, such as the Greek letter pi instead of
the string pi.
full_prec : bool or string, optional (default="auto")
Use full precision.
order : bool or string, optional (default=None)
Set to 'none' for long expressions if slow; default is None.
use_unicode_sqrt_char : bool, optional (default=True)
Use compact single-character square root symbol (when unambiguous).
"""
print(pretty(expr, wrap_line=wrap_line, num_columns=num_columns,
use_unicode=use_unicode, full_prec=full_prec, order=order,
use_unicode_sqrt_char=use_unicode_sqrt_char))
pprint = pretty_print
def pager_print(expr, **settings):
"""Prints expr using the pager, in pretty form.
This invokes a pager command using pydoc. Lines are not wrapped
automatically. This routine is meant to be used with a pager that allows
sideways scrolling, like ``less -S``.
Parameters are the same as for ``pretty_print``. If you wish to wrap lines,
pass ``num_columns=None`` to auto-detect the width of the terminal.
"""
from pydoc import pager
from locale import getpreferredencoding
if 'num_columns' not in settings:
settings['num_columns'] = 500000 # disable line wrap
pager(pretty(expr, **settings).encode(getpreferredencoding()))
|
2572fdd0984f412528eadeddca4ad3da9236d05d531619ef2fcc1889eb4ba7ac
|
from sympy.utilities.pytest import raises
from sympy import (symbols, Function, Integer, Matrix, Abs,
Rational, Float, S, WildFunction, ImmutableDenseMatrix, sin, true, false, ones,
sqrt, root, AlgebraicNumber, Symbol, Dummy, Wild)
from sympy.core.compatibility import exec_
from sympy.geometry import Point, Ellipse
from sympy.printing import srepr
from sympy.polys import ring, field, ZZ, QQ, lex, grlex, Poly
from sympy.polys.polyclasses import DMP
from sympy.polys.agca.extensions import FiniteExtension
x, y = symbols('x,y')
# eval(srepr(expr)) == expr has to succeed in the right environment. The right
# environment is the scope of "from sympy import *" for most cases.
ENV = {}
exec_("from sympy import *", ENV)
def sT(expr, string):
"""
sT := sreprTest
Tests that srepr delivers the expected string and that
the condition eval(srepr(expr))==expr holds.
"""
assert srepr(expr) == string
assert eval(string, ENV) == expr
def test_printmethod():
class R(Abs):
def _sympyrepr(self, printer):
return "foo(%s)" % printer._print(self.args[0])
assert srepr(R(x)) == "foo(Symbol('x'))"
def test_Add():
sT(x + y, "Add(Symbol('x'), Symbol('y'))")
assert srepr(x**2 + 1, order='lex') == "Add(Pow(Symbol('x'), Integer(2)), Integer(1))"
assert srepr(x**2 + 1, order='old') == "Add(Integer(1), Pow(Symbol('x'), Integer(2)))"
def test_more_than_255_args_issue_10259():
from sympy import Add, Mul
for op in (Add, Mul):
expr = op(*symbols('x:256'))
assert eval(srepr(expr)) == expr
def test_Function():
sT(Function("f")(x), "Function('f')(Symbol('x'))")
# test unapplied Function
sT(Function('f'), "Function('f')")
sT(sin(x), "sin(Symbol('x'))")
sT(sin, "sin")
def test_Geometry():
sT(Point(0, 0), "Point2D(Integer(0), Integer(0))")
sT(Ellipse(Point(0, 0), 5, 1),
"Ellipse(Point2D(Integer(0), Integer(0)), Integer(5), Integer(1))")
# TODO more tests
def test_Singletons():
sT(S.Catalan, 'Catalan')
sT(S.ComplexInfinity, 'zoo')
sT(S.EulerGamma, 'EulerGamma')
sT(S.Exp1, 'E')
sT(S.GoldenRatio, 'GoldenRatio')
sT(S.TribonacciConstant, 'TribonacciConstant')
sT(S.Half, 'Rational(1, 2)')
sT(S.ImaginaryUnit, 'I')
sT(S.Infinity, 'oo')
sT(S.NaN, 'nan')
sT(S.NegativeInfinity, '-oo')
sT(S.NegativeOne, 'Integer(-1)')
sT(S.One, 'Integer(1)')
sT(S.Pi, 'pi')
sT(S.Zero, 'Integer(0)')
def test_Integer():
sT(Integer(4), "Integer(4)")
def test_list():
sT([x, Integer(4)], "[Symbol('x'), Integer(4)]")
def test_Matrix():
for cls, name in [(Matrix, "MutableDenseMatrix"), (ImmutableDenseMatrix, "ImmutableDenseMatrix")]:
sT(cls([[x**+1, 1], [y, x + y]]),
"%s([[Symbol('x'), Integer(1)], [Symbol('y'), Add(Symbol('x'), Symbol('y'))]])" % name)
sT(cls(), "%s([])" % name)
sT(cls([[x**+1, 1], [y, x + y]]), "%s([[Symbol('x'), Integer(1)], [Symbol('y'), Add(Symbol('x'), Symbol('y'))]])" % name)
def test_empty_Matrix():
sT(ones(0, 3), "MutableDenseMatrix(0, 3, [])")
sT(ones(4, 0), "MutableDenseMatrix(4, 0, [])")
sT(ones(0, 0), "MutableDenseMatrix([])")
def test_Rational():
sT(Rational(1, 3), "Rational(1, 3)")
sT(Rational(-1, 3), "Rational(-1, 3)")
def test_Float():
sT(Float('1.23', dps=3), "Float('1.22998', precision=13)")
sT(Float('1.23456789', dps=9), "Float('1.23456788994', precision=33)")
sT(Float('1.234567890123456789', dps=19),
"Float('1.234567890123456789013', precision=66)")
sT(Float('0.60038617995049726', dps=15),
"Float('0.60038617995049726', precision=53)")
sT(Float('1.23', precision=13), "Float('1.22998', precision=13)")
sT(Float('1.23456789', precision=33),
"Float('1.23456788994', precision=33)")
sT(Float('1.234567890123456789', precision=66),
"Float('1.234567890123456789013', precision=66)")
sT(Float('0.60038617995049726', precision=53),
"Float('0.60038617995049726', precision=53)")
sT(Float('0.60038617995049726', 15),
"Float('0.60038617995049726', precision=53)")
def test_Symbol():
sT(x, "Symbol('x')")
sT(y, "Symbol('y')")
sT(Symbol('x', negative=True), "Symbol('x', negative=True)")
def test_Symbol_two_assumptions():
x = Symbol('x', negative=0, integer=1)
# order could vary
s1 = "Symbol('x', integer=True, negative=False)"
s2 = "Symbol('x', negative=False, integer=True)"
assert srepr(x) in (s1, s2)
assert eval(srepr(x), ENV) == x
def test_Symbol_no_special_commutative_treatment():
sT(Symbol('x'), "Symbol('x')")
sT(Symbol('x', commutative=False), "Symbol('x', commutative=False)")
sT(Symbol('x', commutative=0), "Symbol('x', commutative=False)")
sT(Symbol('x', commutative=True), "Symbol('x', commutative=True)")
sT(Symbol('x', commutative=1), "Symbol('x', commutative=True)")
def test_Wild():
sT(Wild('x', even=True), "Wild('x', even=True)")
def test_Dummy():
d = Dummy('d')
sT(d, "Dummy('d', dummy_index=%s)" % str(d.dummy_index))
def test_Dummy_assumption():
d = Dummy('d', nonzero=True)
assert d == eval(srepr(d))
s1 = "Dummy('d', dummy_index=%s, nonzero=True)" % str(d.dummy_index)
s2 = "Dummy('d', nonzero=True, dummy_index=%s)" % str(d.dummy_index)
assert srepr(d) in (s1, s2)
def test_Dummy_from_Symbol():
# should not get the full dictionary of assumptions
n = Symbol('n', integer=True)
d = n.as_dummy()
assert srepr(d
) == "Dummy('n', dummy_index=%s)" % str(d.dummy_index)
def test_tuple():
sT((x,), "(Symbol('x'),)")
sT((x, y), "(Symbol('x'), Symbol('y'))")
def test_WildFunction():
sT(WildFunction('w'), "WildFunction('w')")
def test_settins():
raises(TypeError, lambda: srepr(x, method="garbage"))
def test_Mul():
sT(3*x**3*y, "Mul(Integer(3), Pow(Symbol('x'), Integer(3)), Symbol('y'))")
assert srepr(3*x**3*y, order='old') == "Mul(Integer(3), Symbol('y'), Pow(Symbol('x'), Integer(3)))"
def test_AlgebraicNumber():
a = AlgebraicNumber(sqrt(2))
sT(a, "AlgebraicNumber(Pow(Integer(2), Rational(1, 2)), [Integer(1), Integer(0)])")
a = AlgebraicNumber(root(-2, 3))
sT(a, "AlgebraicNumber(Pow(Integer(-2), Rational(1, 3)), [Integer(1), Integer(0)])")
def test_PolyRing():
assert srepr(ring("x", ZZ, lex)[0]) == "PolyRing((Symbol('x'),), ZZ, lex)"
assert srepr(ring("x,y", QQ, grlex)[0]) == "PolyRing((Symbol('x'), Symbol('y')), QQ, grlex)"
assert srepr(ring("x,y,z", ZZ["t"], lex)[0]) == "PolyRing((Symbol('x'), Symbol('y'), Symbol('z')), ZZ[t], lex)"
def test_FracField():
assert srepr(field("x", ZZ, lex)[0]) == "FracField((Symbol('x'),), ZZ, lex)"
assert srepr(field("x,y", QQ, grlex)[0]) == "FracField((Symbol('x'), Symbol('y')), QQ, grlex)"
assert srepr(field("x,y,z", ZZ["t"], lex)[0]) == "FracField((Symbol('x'), Symbol('y'), Symbol('z')), ZZ[t], lex)"
def test_PolyElement():
R, x, y = ring("x,y", ZZ)
assert srepr(3*x**2*y + 1) == "PolyElement(PolyRing((Symbol('x'), Symbol('y')), ZZ, lex), [((2, 1), 3), ((0, 0), 1)])"
def test_FracElement():
F, x, y = field("x,y", ZZ)
assert srepr((3*x**2*y + 1)/(x - y**2)) == "FracElement(FracField((Symbol('x'), Symbol('y')), ZZ, lex), [((2, 1), 3), ((0, 0), 1)], [((1, 0), 1), ((0, 2), -1)])"
def test_FractionField():
assert srepr(QQ.frac_field(x)) == \
"FractionField(FracField((Symbol('x'),), QQ, lex))"
assert srepr(QQ.frac_field(x, y, order=grlex)) == \
"FractionField(FracField((Symbol('x'), Symbol('y')), QQ, grlex))"
def test_PolynomialRingBase():
assert srepr(ZZ.old_poly_ring(x)) == \
"GlobalPolynomialRing(ZZ, Symbol('x'))"
assert srepr(ZZ[x].old_poly_ring(y)) == \
"GlobalPolynomialRing(ZZ[x], Symbol('y'))"
assert srepr(QQ.frac_field(x).old_poly_ring(y)) == \
"GlobalPolynomialRing(FractionField(FracField((Symbol('x'),), QQ, lex)), Symbol('y'))"
def test_DMP():
assert srepr(DMP([1, 2], ZZ)) == 'DMP([1, 2], ZZ)'
assert srepr(ZZ.old_poly_ring(x)([1, 2])) == \
"DMP([1, 2], ZZ, ring=GlobalPolynomialRing(ZZ, Symbol('x')))"
def test_FiniteExtension():
assert srepr(FiniteExtension(Poly(x**2 + 1, x))) == \
"FiniteExtension(Poly(x**2 + 1, x, domain='ZZ'))"
def test_ExtensionElement():
A = FiniteExtension(Poly(x**2 + 1, x))
assert srepr(A.generator) == \
"ExtElem(DMP([1, 0], ZZ, ring=GlobalPolynomialRing(ZZ, Symbol('x'))), FiniteExtension(Poly(x**2 + 1, x, domain='ZZ')))"
def test_BooleanAtom():
assert srepr(true) == "true"
assert srepr(false) == "false"
def test_Integers():
sT(S.Integers, "Integers")
def test_Naturals():
sT(S.Naturals, "Naturals")
def test_Naturals0():
sT(S.Naturals0, "Naturals0")
def test_Reals():
sT(S.Reals, "Reals")
|
36adb2a902d4c92fdbc837ef73f5f57b842f6154dbc9058acb0c33ad0b9fa82d
|
from sympy import (Abs, Catalan, cos, Derivative, E, EulerGamma, exp,
factorial, factorial2, Function, GoldenRatio, TribonacciConstant, I,
Integer, Integral, Interval, Lambda, Limit, Matrix, nan, O, oo, pi, Pow,
Rational, Float, Rel, S, sin, SparseMatrix, sqrt, summation, Sum, Symbol,
symbols, Wild, WildFunction, zeta, zoo, Dummy, Dict, Tuple, FiniteSet, factor,
subfactorial, true, false, Equivalent, Xor, Complement, SymmetricDifference,
AccumBounds, UnevaluatedExpr, Eq, Ne, Quaternion, Subs)
from sympy.core import Expr, Mul
from sympy.physics.units import second, joule
from sympy.polys import Poly, rootof, RootSum, groebner, ring, field, ZZ, QQ, lex, grlex
from sympy.geometry import Point, Circle
from sympy.utilities.pytest import raises
from sympy.core.compatibility import range
from sympy.printing import sstr, sstrrepr, StrPrinter
from sympy.core.trace import Tr
from sympy import MatrixSymbol
from sympy import factorial, log, integrate
x, y, z, w, t = symbols('x,y,z,w,t')
d = Dummy('d')
def test_printmethod():
class R(Abs):
def _sympystr(self, printer):
return "foo(%s)" % printer._print(self.args[0])
assert sstr(R(x)) == "foo(x)"
class R(Abs):
def _sympystr(self, printer):
return "foo"
assert sstr(R(x)) == "foo"
def test_Abs():
assert str(Abs(x)) == "Abs(x)"
assert str(Abs(Rational(1, 6))) == "1/6"
assert str(Abs(Rational(-1, 6))) == "1/6"
def test_Add():
assert str(x + y) == "x + y"
assert str(x + 1) == "x + 1"
assert str(x + x**2) == "x**2 + x"
assert str(5 + x + y + x*y + x**2 + y**2) == "x**2 + x*y + x + y**2 + y + 5"
assert str(1 + x + x**2/2 + x**3/3) == "x**3/3 + x**2/2 + x + 1"
assert str(2*x - 7*x**2 + 2 + 3*y) == "-7*x**2 + 2*x + 3*y + 2"
assert str(x - y) == "x - y"
assert str(2 - x) == "-x + 2"
assert str(x - 2) == "x - 2"
assert str(x - y - z - w) == "-w + x - y - z"
assert str(x - z*y**2*z*w) == "-w*y**2*z**2 + x"
assert str(x - 1*y*x*y) == "-x*y**2 + x"
assert str(sin(x).series(x, 0, 15)) == "x - x**3/6 + x**5/120 - x**7/5040 + x**9/362880 - x**11/39916800 + x**13/6227020800 + O(x**15)"
def test_Catalan():
assert str(Catalan) == "Catalan"
def test_ComplexInfinity():
assert str(zoo) == "zoo"
def test_Derivative():
assert str(Derivative(x, y)) == "Derivative(x, y)"
assert str(Derivative(x**2, x, evaluate=False)) == "Derivative(x**2, x)"
assert str(Derivative(
x**2/y, x, y, evaluate=False)) == "Derivative(x**2/y, x, y)"
def test_dict():
assert str({1: 1 + x}) == sstr({1: 1 + x}) == "{1: x + 1}"
assert str({1: x**2, 2: y*x}) in ("{1: x**2, 2: x*y}", "{2: x*y, 1: x**2}")
assert sstr({1: x**2, 2: y*x}) == "{1: x**2, 2: x*y}"
def test_Dict():
assert str(Dict({1: 1 + x})) == sstr({1: 1 + x}) == "{1: x + 1}"
assert str(Dict({1: x**2, 2: y*x})) in (
"{1: x**2, 2: x*y}", "{2: x*y, 1: x**2}")
assert sstr(Dict({1: x**2, 2: y*x})) == "{1: x**2, 2: x*y}"
def test_Dummy():
assert str(d) == "_d"
assert str(d + x) == "_d + x"
def test_EulerGamma():
assert str(EulerGamma) == "EulerGamma"
def test_Exp():
assert str(E) == "E"
def test_factorial():
n = Symbol('n', integer=True)
assert str(factorial(-2)) == "zoo"
assert str(factorial(0)) == "1"
assert str(factorial(7)) == "5040"
assert str(factorial(n)) == "factorial(n)"
assert str(factorial(2*n)) == "factorial(2*n)"
assert str(factorial(factorial(n))) == 'factorial(factorial(n))'
assert str(factorial(factorial2(n))) == 'factorial(factorial2(n))'
assert str(factorial2(factorial(n))) == 'factorial2(factorial(n))'
assert str(factorial2(factorial2(n))) == 'factorial2(factorial2(n))'
assert str(subfactorial(3)) == "2"
assert str(subfactorial(n)) == "subfactorial(n)"
assert str(subfactorial(2*n)) == "subfactorial(2*n)"
def test_Function():
f = Function('f')
fx = f(x)
w = WildFunction('w')
assert str(f) == "f"
assert str(fx) == "f(x)"
assert str(w) == "w_"
def test_Geometry():
assert sstr(Point(0, 0)) == 'Point2D(0, 0)'
assert sstr(Circle(Point(0, 0), 3)) == 'Circle(Point2D(0, 0), 3)'
# TODO test other Geometry entities
def test_GoldenRatio():
assert str(GoldenRatio) == "GoldenRatio"
def test_TribonacciConstant():
assert str(TribonacciConstant) == "TribonacciConstant"
def test_ImaginaryUnit():
assert str(I) == "I"
def test_Infinity():
assert str(oo) == "oo"
assert str(oo*I) == "oo*I"
def test_Integer():
assert str(Integer(-1)) == "-1"
assert str(Integer(1)) == "1"
assert str(Integer(-3)) == "-3"
assert str(Integer(0)) == "0"
assert str(Integer(25)) == "25"
def test_Integral():
assert str(Integral(sin(x), y)) == "Integral(sin(x), y)"
assert str(Integral(sin(x), (y, 0, 1))) == "Integral(sin(x), (y, 0, 1))"
def test_Interval():
n = (S.NegativeInfinity, 1, 2, S.Infinity)
for i in range(len(n)):
for j in range(i + 1, len(n)):
for l in (True, False):
for r in (True, False):
ival = Interval(n[i], n[j], l, r)
assert S(str(ival)) == ival
def test_AccumBounds():
a = Symbol('a', real=True)
assert str(AccumBounds(0, a)) == "AccumBounds(0, a)"
assert str(AccumBounds(0, 1)) == "AccumBounds(0, 1)"
def test_Lambda():
assert str(Lambda(d, d**2)) == "Lambda(_d, _d**2)"
# issue 2908
assert str(Lambda((), 1)) == "Lambda((), 1)"
assert str(Lambda((), x)) == "Lambda((), x)"
def test_Limit():
assert str(Limit(sin(x)/x, x, y)) == "Limit(sin(x)/x, x, y)"
assert str(Limit(1/x, x, 0)) == "Limit(1/x, x, 0)"
assert str(
Limit(sin(x)/x, x, y, dir="-")) == "Limit(sin(x)/x, x, y, dir='-')"
def test_list():
assert str([x]) == sstr([x]) == "[x]"
assert str([x**2, x*y + 1]) == sstr([x**2, x*y + 1]) == "[x**2, x*y + 1]"
assert str([x**2, [y + x]]) == sstr([x**2, [y + x]]) == "[x**2, [x + y]]"
def test_Matrix_str():
M = Matrix([[x**+1, 1], [y, x + y]])
assert str(M) == "Matrix([[x, 1], [y, x + y]])"
assert sstr(M) == "Matrix([\n[x, 1],\n[y, x + y]])"
M = Matrix([[1]])
assert str(M) == sstr(M) == "Matrix([[1]])"
M = Matrix([[1, 2]])
assert str(M) == sstr(M) == "Matrix([[1, 2]])"
M = Matrix()
assert str(M) == sstr(M) == "Matrix(0, 0, [])"
M = Matrix(0, 1, lambda i, j: 0)
assert str(M) == sstr(M) == "Matrix(0, 1, [])"
def test_Mul():
assert str(x/y) == "x/y"
assert str(y/x) == "y/x"
assert str(x/y/z) == "x/(y*z)"
assert str((x + 1)/(y + 2)) == "(x + 1)/(y + 2)"
assert str(2*x/3) == '2*x/3'
assert str(-2*x/3) == '-2*x/3'
assert str(-1.0*x) == '-1.0*x'
assert str(1.0*x) == '1.0*x'
# For issue 14160
assert str(Mul(-2, x, Pow(Mul(y,y,evaluate=False), -1, evaluate=False),
evaluate=False)) == '-2*x/(y*y)'
class CustomClass1(Expr):
is_commutative = True
class CustomClass2(Expr):
is_commutative = True
cc1 = CustomClass1()
cc2 = CustomClass2()
assert str(Rational(2)*cc1) == '2*CustomClass1()'
assert str(cc1*Rational(2)) == '2*CustomClass1()'
assert str(cc1*Float("1.5")) == '1.5*CustomClass1()'
assert str(cc2*Rational(2)) == '2*CustomClass2()'
assert str(cc2*Rational(2)*cc1) == '2*CustomClass1()*CustomClass2()'
assert str(cc1*Rational(2)*cc2) == '2*CustomClass1()*CustomClass2()'
def test_NaN():
assert str(nan) == "nan"
def test_NegativeInfinity():
assert str(-oo) == "-oo"
def test_Order():
assert str(O(x)) == "O(x)"
assert str(O(x**2)) == "O(x**2)"
assert str(O(x*y)) == "O(x*y, x, y)"
assert str(O(x, x)) == "O(x)"
assert str(O(x, (x, 0))) == "O(x)"
assert str(O(x, (x, oo))) == "O(x, (x, oo))"
assert str(O(x, x, y)) == "O(x, x, y)"
assert str(O(x, x, y)) == "O(x, x, y)"
assert str(O(x, (x, oo), (y, oo))) == "O(x, (x, oo), (y, oo))"
def test_Permutation_Cycle():
from sympy.combinatorics import Permutation, Cycle
# general principle: economically, canonically show all moved elements
# and the size of the permutation.
for p, s in [
(Cycle(),
'()'),
(Cycle(2),
'(2)'),
(Cycle(2, 1),
'(1 2)'),
(Cycle(1, 2)(5)(6, 7)(10),
'(1 2)(6 7)(10)'),
(Cycle(3, 4)(1, 2)(3, 4),
'(1 2)(4)'),
]:
assert str(p) == s
Permutation.print_cyclic = False
for p, s in [
(Permutation([]),
'Permutation([])'),
(Permutation([], size=1),
'Permutation([0])'),
(Permutation([], size=2),
'Permutation([0, 1])'),
(Permutation([], size=10),
'Permutation([], size=10)'),
(Permutation([1, 0, 2]),
'Permutation([1, 0, 2])'),
(Permutation([1, 0, 2, 3, 4, 5]),
'Permutation([1, 0], size=6)'),
(Permutation([1, 0, 2, 3, 4, 5], size=10),
'Permutation([1, 0], size=10)'),
]:
assert str(p) == s
Permutation.print_cyclic = True
for p, s in [
(Permutation([]),
'()'),
(Permutation([], size=1),
'(0)'),
(Permutation([], size=2),
'(1)'),
(Permutation([], size=10),
'(9)'),
(Permutation([1, 0, 2]),
'(2)(0 1)'),
(Permutation([1, 0, 2, 3, 4, 5]),
'(5)(0 1)'),
(Permutation([1, 0, 2, 3, 4, 5], size=10),
'(9)(0 1)'),
(Permutation([0, 1, 3, 2, 4, 5], size=10),
'(9)(2 3)'),
]:
assert str(p) == s
def test_Pi():
assert str(pi) == "pi"
def test_Poly():
assert str(Poly(0, x)) == "Poly(0, x, domain='ZZ')"
assert str(Poly(1, x)) == "Poly(1, x, domain='ZZ')"
assert str(Poly(x, x)) == "Poly(x, x, domain='ZZ')"
assert str(Poly(2*x + 1, x)) == "Poly(2*x + 1, x, domain='ZZ')"
assert str(Poly(2*x - 1, x)) == "Poly(2*x - 1, x, domain='ZZ')"
assert str(Poly(-1, x)) == "Poly(-1, x, domain='ZZ')"
assert str(Poly(-x, x)) == "Poly(-x, x, domain='ZZ')"
assert str(Poly(-2*x + 1, x)) == "Poly(-2*x + 1, x, domain='ZZ')"
assert str(Poly(-2*x - 1, x)) == "Poly(-2*x - 1, x, domain='ZZ')"
assert str(Poly(x - 1, x)) == "Poly(x - 1, x, domain='ZZ')"
assert str(Poly(2*x + x**5, x)) == "Poly(x**5 + 2*x, x, domain='ZZ')"
assert str(Poly(3**(2*x), 3**x)) == "Poly((3**x)**2, 3**x, domain='ZZ')"
assert str(Poly((x**2)**x)) == "Poly(((x**2)**x), (x**2)**x, domain='ZZ')"
assert str(Poly((x + y)**3, (x + y), expand=False)
) == "Poly((x + y)**3, x + y, domain='ZZ')"
assert str(Poly((x - 1)**2, (x - 1), expand=False)
) == "Poly((x - 1)**2, x - 1, domain='ZZ')"
assert str(
Poly(x**2 + 1 + y, x)) == "Poly(x**2 + y + 1, x, domain='ZZ[y]')"
assert str(
Poly(x**2 - 1 + y, x)) == "Poly(x**2 + y - 1, x, domain='ZZ[y]')"
assert str(Poly(x**2 + I*x, x)) == "Poly(x**2 + I*x, x, domain='EX')"
assert str(Poly(x**2 - I*x, x)) == "Poly(x**2 - I*x, x, domain='EX')"
assert str(Poly(-x*y*z + x*y - 1, x, y, z)
) == "Poly(-x*y*z + x*y - 1, x, y, z, domain='ZZ')"
assert str(Poly(-w*x**21*y**7*z + (1 + w)*z**3 - 2*x*z + 1, x, y, z)) == \
"Poly(-w*x**21*y**7*z - 2*x*z + (w + 1)*z**3 + 1, x, y, z, domain='ZZ[w]')"
assert str(Poly(x**2 + 1, x, modulus=2)) == "Poly(x**2 + 1, x, modulus=2)"
assert str(Poly(2*x**2 + 3*x + 4, x, modulus=17)) == "Poly(2*x**2 + 3*x + 4, x, modulus=17)"
def test_PolyRing():
assert str(ring("x", ZZ, lex)[0]) == "Polynomial ring in x over ZZ with lex order"
assert str(ring("x,y", QQ, grlex)[0]) == "Polynomial ring in x, y over QQ with grlex order"
assert str(ring("x,y,z", ZZ["t"], lex)[0]) == "Polynomial ring in x, y, z over ZZ[t] with lex order"
def test_FracField():
assert str(field("x", ZZ, lex)[0]) == "Rational function field in x over ZZ with lex order"
assert str(field("x,y", QQ, grlex)[0]) == "Rational function field in x, y over QQ with grlex order"
assert str(field("x,y,z", ZZ["t"], lex)[0]) == "Rational function field in x, y, z over ZZ[t] with lex order"
def test_PolyElement():
Ruv, u,v = ring("u,v", ZZ)
Rxyz, x,y,z = ring("x,y,z", Ruv)
assert str(x - x) == "0"
assert str(x - 1) == "x - 1"
assert str(x + 1) == "x + 1"
assert str(x**2) == "x**2"
assert str(x**(-2)) == "x**(-2)"
assert str(x**QQ(1, 2)) == "x**(1/2)"
assert str((u**2 + 3*u*v + 1)*x**2*y + u + 1) == "(u**2 + 3*u*v + 1)*x**2*y + u + 1"
assert str((u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x) == "(u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x"
assert str((u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x + 1) == "(u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x + 1"
assert str((-u**2 + 3*u*v - 1)*x**2*y - (u + 1)*x - 1) == "-(u**2 - 3*u*v + 1)*x**2*y - (u + 1)*x - 1"
assert str(-(v**2 + v + 1)*x + 3*u*v + 1) == "-(v**2 + v + 1)*x + 3*u*v + 1"
assert str(-(v**2 + v + 1)*x - 3*u*v + 1) == "-(v**2 + v + 1)*x - 3*u*v + 1"
def test_FracElement():
Fuv, u,v = field("u,v", ZZ)
Fxyzt, x,y,z,t = field("x,y,z,t", Fuv)
assert str(x - x) == "0"
assert str(x - 1) == "x - 1"
assert str(x + 1) == "x + 1"
assert str(x/3) == "x/3"
assert str(x/z) == "x/z"
assert str(x*y/z) == "x*y/z"
assert str(x/(z*t)) == "x/(z*t)"
assert str(x*y/(z*t)) == "x*y/(z*t)"
assert str((x - 1)/y) == "(x - 1)/y"
assert str((x + 1)/y) == "(x + 1)/y"
assert str((-x - 1)/y) == "(-x - 1)/y"
assert str((x + 1)/(y*z)) == "(x + 1)/(y*z)"
assert str(-y/(x + 1)) == "-y/(x + 1)"
assert str(y*z/(x + 1)) == "y*z/(x + 1)"
assert str(((u + 1)*x*y + 1)/((v - 1)*z - 1)) == "((u + 1)*x*y + 1)/((v - 1)*z - 1)"
assert str(((u + 1)*x*y + 1)/((v - 1)*z - t*u*v - 1)) == "((u + 1)*x*y + 1)/((v - 1)*z - u*v*t - 1)"
def test_Pow():
assert str(x**-1) == "1/x"
assert str(x**-2) == "x**(-2)"
assert str(x**2) == "x**2"
assert str((x + y)**-1) == "1/(x + y)"
assert str((x + y)**-2) == "(x + y)**(-2)"
assert str((x + y)**2) == "(x + y)**2"
assert str((x + y)**(1 + x)) == "(x + y)**(x + 1)"
assert str(x**Rational(1, 3)) == "x**(1/3)"
assert str(1/x**Rational(1, 3)) == "x**(-1/3)"
assert str(sqrt(sqrt(x))) == "x**(1/4)"
# not the same as x**-1
assert str(x**-1.0) == 'x**(-1.0)'
# see issue #2860
assert str(Pow(S(2), -1.0, evaluate=False)) == '2**(-1.0)'
def test_sqrt():
assert str(sqrt(x)) == "sqrt(x)"
assert str(sqrt(x**2)) == "sqrt(x**2)"
assert str(1/sqrt(x)) == "1/sqrt(x)"
assert str(1/sqrt(x**2)) == "1/sqrt(x**2)"
assert str(y/sqrt(x)) == "y/sqrt(x)"
assert str(x**0.5) == "x**0.5"
assert str(1/x**0.5) == "x**(-0.5)"
def test_Rational():
n1 = Rational(1, 4)
n2 = Rational(1, 3)
n3 = Rational(2, 4)
n4 = Rational(2, -4)
n5 = Rational(0)
n7 = Rational(3)
n8 = Rational(-3)
assert str(n1*n2) == "1/12"
assert str(n1*n2) == "1/12"
assert str(n3) == "1/2"
assert str(n1*n3) == "1/8"
assert str(n1 + n3) == "3/4"
assert str(n1 + n2) == "7/12"
assert str(n1 + n4) == "-1/4"
assert str(n4*n4) == "1/4"
assert str(n4 + n2) == "-1/6"
assert str(n4 + n5) == "-1/2"
assert str(n4*n5) == "0"
assert str(n3 + n4) == "0"
assert str(n1**n7) == "1/64"
assert str(n2**n7) == "1/27"
assert str(n2**n8) == "27"
assert str(n7**n8) == "1/27"
assert str(Rational("-25")) == "-25"
assert str(Rational("1.25")) == "5/4"
assert str(Rational("-2.6e-2")) == "-13/500"
assert str(S("25/7")) == "25/7"
assert str(S("-123/569")) == "-123/569"
assert str(S("0.1[23]", rational=1)) == "61/495"
assert str(S("5.1[666]", rational=1)) == "31/6"
assert str(S("-5.1[666]", rational=1)) == "-31/6"
assert str(S("0.[9]", rational=1)) == "1"
assert str(S("-0.[9]", rational=1)) == "-1"
assert str(sqrt(Rational(1, 4))) == "1/2"
assert str(sqrt(Rational(1, 36))) == "1/6"
assert str((123**25) ** Rational(1, 25)) == "123"
assert str((123**25 + 1)**Rational(1, 25)) != "123"
assert str((123**25 - 1)**Rational(1, 25)) != "123"
assert str((123**25 - 1)**Rational(1, 25)) != "122"
assert str(sqrt(Rational(81, 36))**3) == "27/8"
assert str(1/sqrt(Rational(81, 36))**3) == "8/27"
assert str(sqrt(-4)) == str(2*I)
assert str(2**Rational(1, 10**10)) == "2**(1/10000000000)"
assert sstr(Rational(2, 3), sympy_integers=True) == "S(2)/3"
x = Symbol("x")
assert sstr(x**Rational(2, 3), sympy_integers=True) == "x**(S(2)/3)"
assert sstr(Eq(x, Rational(2, 3)), sympy_integers=True) == "Eq(x, S(2)/3)"
assert sstr(Limit(x, x, Rational(7, 2)), sympy_integers=True) == \
"Limit(x, x, S(7)/2)"
def test_Float():
# NOTE dps is the whole number of decimal digits
assert str(Float('1.23', dps=1 + 2)) == '1.23'
assert str(Float('1.23456789', dps=1 + 8)) == '1.23456789'
assert str(
Float('1.234567890123456789', dps=1 + 18)) == '1.234567890123456789'
assert str(pi.evalf(1 + 2)) == '3.14'
assert str(pi.evalf(1 + 14)) == '3.14159265358979'
assert str(pi.evalf(1 + 64)) == ('3.141592653589793238462643383279'
'5028841971693993751058209749445923')
assert str(pi.round(-1)) == '0.'
assert str((pi**400 - (pi**400).round(1)).n(2)) == '-0.e+88'
assert str(Float(S.Infinity)) == 'inf'
assert str(Float(S.NegativeInfinity)) == '-inf'
def test_Relational():
assert str(Rel(x, y, "<")) == "x < y"
assert str(Rel(x + y, y, "==")) == "Eq(x + y, y)"
assert str(Rel(x, y, "!=")) == "Ne(x, y)"
assert str(Eq(x, 1) | Eq(x, 2)) == "Eq(x, 1) | Eq(x, 2)"
assert str(Ne(x, 1) & Ne(x, 2)) == "Ne(x, 1) & Ne(x, 2)"
def test_CRootOf():
assert str(rootof(x**5 + 2*x - 1, 0)) == "CRootOf(x**5 + 2*x - 1, 0)"
def test_RootSum():
f = x**5 + 2*x - 1
assert str(
RootSum(f, Lambda(z, z), auto=False)) == "RootSum(x**5 + 2*x - 1)"
assert str(RootSum(f, Lambda(
z, z**2), auto=False)) == "RootSum(x**5 + 2*x - 1, Lambda(z, z**2))"
def test_GroebnerBasis():
assert str(groebner(
[], x, y)) == "GroebnerBasis([], x, y, domain='ZZ', order='lex')"
F = [x**2 - 3*y - x + 1, y**2 - 2*x + y - 1]
assert str(groebner(F, order='grlex')) == \
"GroebnerBasis([x**2 - x - 3*y + 1, y**2 - 2*x + y - 1], x, y, domain='ZZ', order='grlex')"
assert str(groebner(F, order='lex')) == \
"GroebnerBasis([2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7], x, y, domain='ZZ', order='lex')"
def test_set():
assert sstr(set()) == 'set()'
assert sstr(frozenset()) == 'frozenset()'
assert sstr(set([1])) == '{1}'
assert sstr(frozenset([1])) == 'frozenset({1})'
assert sstr(set([1, 2, 3])) == '{1, 2, 3}'
assert sstr(frozenset([1, 2, 3])) == 'frozenset({1, 2, 3})'
assert sstr(
set([1, x, x**2, x**3, x**4])) == '{1, x, x**2, x**3, x**4}'
assert sstr(
frozenset([1, x, x**2, x**3, x**4])) == 'frozenset({1, x, x**2, x**3, x**4})'
def test_SparseMatrix():
M = SparseMatrix([[x**+1, 1], [y, x + y]])
assert str(M) == "Matrix([[x, 1], [y, x + y]])"
assert sstr(M) == "Matrix([\n[x, 1],\n[y, x + y]])"
def test_Sum():
assert str(summation(cos(3*z), (z, x, y))) == "Sum(cos(3*z), (z, x, y))"
assert str(Sum(x*y**2, (x, -2, 2), (y, -5, 5))) == \
"Sum(x*y**2, (x, -2, 2), (y, -5, 5))"
def test_Symbol():
assert str(y) == "y"
assert str(x) == "x"
e = x
assert str(e) == "x"
def test_tuple():
assert str((x,)) == sstr((x,)) == "(x,)"
assert str((x + y, 1 + x)) == sstr((x + y, 1 + x)) == "(x + y, x + 1)"
assert str((x + y, (
1 + x, x**2))) == sstr((x + y, (1 + x, x**2))) == "(x + y, (x + 1, x**2))"
def test_Quaternion_str_printer():
q = Quaternion(x, y, z, t)
assert str(q) == "x + y*i + z*j + t*k"
q = Quaternion(x,y,z,x*t)
assert str(q) == "x + y*i + z*j + t*x*k"
q = Quaternion(x,y,z,x+t)
assert str(q) == "x + y*i + z*j + (t + x)*k"
def test_Quantity_str():
assert sstr(second, abbrev=True) == "s"
assert sstr(joule, abbrev=True) == "J"
assert str(second) == "second"
assert str(joule) == "joule"
def test_wild_str():
# Check expressions containing Wild not causing infinite recursion
w = Wild('x')
assert str(w + 1) == 'x_ + 1'
assert str(exp(2**w) + 5) == 'exp(2**x_) + 5'
assert str(3*w + 1) == '3*x_ + 1'
assert str(1/w + 1) == '1 + 1/x_'
assert str(w**2 + 1) == 'x_**2 + 1'
assert str(1/(1 - w)) == '1/(-x_ + 1)'
def test_zeta():
assert str(zeta(3)) == "zeta(3)"
def test_issue_3101():
e = x - y
a = str(e)
b = str(e)
assert a == b
def test_issue_3103():
e = -2*sqrt(x) - y/sqrt(x)/2
assert str(e) not in ["(-2)*x**1/2(-1/2)*x**(-1/2)*y",
"-2*x**1/2(-1/2)*x**(-1/2)*y", "-2*x**1/2-1/2*x**-1/2*w"]
assert str(e) == "-2*sqrt(x) - y/(2*sqrt(x))"
def test_issue_4021():
e = Integral(x, x) + 1
assert str(e) == 'Integral(x, x) + 1'
def test_sstrrepr():
assert sstr('abc') == 'abc'
assert sstrrepr('abc') == "'abc'"
e = ['a', 'b', 'c', x]
assert sstr(e) == "[a, b, c, x]"
assert sstrrepr(e) == "['a', 'b', 'c', x]"
def test_infinity():
assert sstr(oo*I) == "oo*I"
def test_full_prec():
assert sstr(S("0.3"), full_prec=True) == "0.300000000000000"
assert sstr(S("0.3"), full_prec="auto") == "0.300000000000000"
assert sstr(S("0.3"), full_prec=False) == "0.3"
assert sstr(S("0.3")*x, full_prec=True) in [
"0.300000000000000*x",
"x*0.300000000000000"
]
assert sstr(S("0.3")*x, full_prec="auto") in [
"0.3*x",
"x*0.3"
]
assert sstr(S("0.3")*x, full_prec=False) in [
"0.3*x",
"x*0.3"
]
def test_noncommutative():
A, B, C = symbols('A,B,C', commutative=False)
assert sstr(A*B*C**-1) == "A*B*C**(-1)"
assert sstr(C**-1*A*B) == "C**(-1)*A*B"
assert sstr(A*C**-1*B) == "A*C**(-1)*B"
assert sstr(sqrt(A)) == "sqrt(A)"
assert sstr(1/sqrt(A)) == "A**(-1/2)"
def test_empty_printer():
str_printer = StrPrinter()
assert str_printer.emptyPrinter("foo") == "foo"
assert str_printer.emptyPrinter(x*y) == "x*y"
assert str_printer.emptyPrinter(32) == "32"
def test_settings():
raises(TypeError, lambda: sstr(S(4), method="garbage"))
def test_RandomDomain():
from sympy.stats import Normal, Die, Exponential, pspace, where
X = Normal('x1', 0, 1)
assert str(where(X > 0)) == "Domain: (0 < x1) & (x1 < oo)"
D = Die('d1', 6)
assert str(where(D > 4)) == "Domain: Eq(d1, 5) | Eq(d1, 6)"
A = Exponential('a', 1)
B = Exponential('b', 1)
assert str(pspace(Tuple(A, B)).domain) == "Domain: (0 <= a) & (0 <= b) & (a < oo) & (b < oo)"
def test_FiniteSet():
assert str(FiniteSet(*range(1, 51))) == '{1, 2, 3, ..., 48, 49, 50}'
assert str(FiniteSet(*range(1, 6))) == '{1, 2, 3, 4, 5}'
def test_PrettyPoly():
from sympy.polys.domains import QQ
F = QQ.frac_field(x, y)
R = QQ[x, y]
assert sstr(F.convert(x/(x + y))) == sstr(x/(x + y))
assert sstr(R.convert(x + y)) == sstr(x + y)
def test_categories():
from sympy.categories import (Object, NamedMorphism,
IdentityMorphism, Category)
A = Object("A")
B = Object("B")
f = NamedMorphism(A, B, "f")
id_A = IdentityMorphism(A)
K = Category("K")
assert str(A) == 'Object("A")'
assert str(f) == 'NamedMorphism(Object("A"), Object("B"), "f")'
assert str(id_A) == 'IdentityMorphism(Object("A"))'
assert str(K) == 'Category("K")'
def test_Tr():
A, B = symbols('A B', commutative=False)
t = Tr(A*B)
assert str(t) == 'Tr(A*B)'
def test_issue_6387():
assert str(factor(-3.0*z + 3)) == '-3.0*(1.0*z - 1.0)'
def test_MatMul_MatAdd():
from sympy import MatrixSymbol
assert str(2*(MatrixSymbol("X", 2, 2) + MatrixSymbol("Y", 2, 2))) == \
"2*(X + Y)"
def test_MatrixSlice():
from sympy.matrices.expressions import MatrixSymbol
assert str(MatrixSymbol('X', 10, 10)[:5, 1:9:2]) == 'X[:5, 1:9:2]'
assert str(MatrixSymbol('X', 10, 10)[5, :5:2]) == 'X[5, :5:2]'
def test_true_false():
assert str(true) == repr(true) == sstr(true) == "True"
assert str(false) == repr(false) == sstr(false) == "False"
def test_Equivalent():
assert str(Equivalent(y, x)) == "Equivalent(x, y)"
def test_Xor():
assert str(Xor(y, x, evaluate=False)) == "Xor(x, y)"
def test_Complement():
assert str(Complement(S.Reals, S.Naturals)) == 'Reals \\ Naturals'
def test_SymmetricDifference():
assert str(SymmetricDifference(Interval(2, 3), Interval(3, 4),evaluate=False)) == \
'SymmetricDifference(Interval(2, 3), Interval(3, 4))'
def test_UnevaluatedExpr():
a, b = symbols("a b")
expr1 = 2*UnevaluatedExpr(a+b)
assert str(expr1) == "2*(a + b)"
def test_MatrixElement_printing():
# test cases for issue #11821
A = MatrixSymbol("A", 1, 3)
B = MatrixSymbol("B", 1, 3)
C = MatrixSymbol("C", 1, 3)
assert(str(A[0, 0]) == "A[0, 0]")
assert(str(3 * A[0, 0]) == "3*A[0, 0]")
F = C[0, 0].subs(C, A - B)
assert str(F) == "(A - B)[0, 0]"
def test_MatrixSymbol_printing():
A = MatrixSymbol("A", 3, 3)
B = MatrixSymbol("B", 3, 3)
assert str(A - A*B - B) == "A - A*B - B"
assert str(A*B - (A+B)) == "-(A + B) + A*B"
assert str(A**(-1)) == "A**(-1)"
assert str(A**3) == "A**3"
def test_Subs_printing():
assert str(Subs(x, (x,), (1,))) == 'Subs(x, x, 1)'
assert str(Subs(x + y, (x, y), (1, 2))) == 'Subs(x + y, (x, y), (1, 2))'
def test_issue_15716():
x = Symbol('x')
e = -3**x*exp(-3)*log(3**x*exp(-3)/factorial(x))/factorial(x)
assert str(Integral(e, (x, -oo, oo)).doit()) == '-(Integral(-3*3**x/factorial(x), (x, -oo, oo))' \
' + Integral(3**x*log(3**x/factorial(x))/factorial(x), (x, -oo, oo)))*exp(-3)'
|
41395480cc3fecb891edce68123d21b35620e28e1e86dceac3dec0289da571ac
|
from sympy import (
Add, Abs, Chi, Ci, CosineTransform, Dict, Ei, Eq, FallingFactorial,
FiniteSet, Float, FourierTransform, Function, Indexed, IndexedBase, Integral,
Interval, InverseCosineTransform, InverseFourierTransform,
InverseLaplaceTransform, InverseMellinTransform, InverseSineTransform,
Lambda, LaplaceTransform, Limit, Matrix, Max, MellinTransform, Min, Mul,
Order, Piecewise, Poly, ring, field, ZZ, Pow, Product, Range, Rational,
RisingFactorial, rootof, RootSum, S, Shi, Si, SineTransform, Subs,
Sum, Symbol, ImageSet, Tuple, Union, Ynm, Znm, arg, asin, acsc, Mod,
assoc_laguerre, assoc_legendre, beta, binomial, catalan, ceiling, Complement,
chebyshevt, chebyshevu, conjugate, cot, coth, diff, dirichlet_eta, euler,
exp, expint, factorial, factorial2, floor, gamma, gegenbauer, hermite,
hyper, im, jacobi, laguerre, legendre, lerchphi, log,
meijerg, oo, polar_lift, polylog, re, root, sin, sqrt, symbols,
uppergamma, zeta, subfactorial, totient, elliptic_k, elliptic_f,
elliptic_e, elliptic_pi, cos, tan, Wild, true, false, Equivalent, Not,
Contains, divisor_sigma, SymmetricDifference, SeqPer, SeqFormula,
SeqAdd, SeqMul, fourier_series, pi, ConditionSet, ComplexRegion, fps,
AccumBounds, reduced_totient, primenu, primeomega, SingularityFunction,
UnevaluatedExpr, Quaternion)
from sympy.ntheory.factor_ import udivisor_sigma
from sympy.abc import mu, tau
from sympy.printing.latex import (latex, translate, greek_letters_set,
tex_greek_dictionary)
from sympy.tensor.array import (ImmutableDenseNDimArray, ImmutableSparseNDimArray,
MutableSparseNDimArray, MutableDenseNDimArray)
from sympy.tensor.array import tensorproduct
from sympy.utilities.pytest import XFAIL, raises
from sympy.functions import DiracDelta, Heaviside, KroneckerDelta, LeviCivita
from sympy.logic import Implies
from sympy.logic.boolalg import And, Or, Xor
from sympy.physics.quantum import Commutator, Operator
from sympy.physics.units import degree, radian, kg, meter, R
from sympy.core.trace import Tr
from sympy.core.compatibility import range
from sympy.combinatorics.permutations import Cycle, Permutation
from sympy import MatrixSymbol, ln
from sympy.vector import CoordSys3D, Cross, Curl, Dot, Divergence, Gradient
from sympy.sets.setexpr import SetExpr
import sympy as sym
class lowergamma(sym.lowergamma):
pass # testing notation inheritance by a subclass with same name
x, y, z, t, a, b, c = symbols('x y z t a b c')
k, m, n = symbols('k m n', integer=True)
def test_printmethod():
class R(Abs):
def _latex(self, printer):
return "foo(%s)" % printer._print(self.args[0])
assert latex(R(x)) == "foo(x)"
class R(Abs):
def _latex(self, printer):
return "foo"
assert latex(R(x)) == "foo"
def test_latex_basic():
assert latex(1 + x) == "x + 1"
assert latex(x**2) == "x^{2}"
assert latex(x**(1 + x)) == "x^{x + 1}"
assert latex(x**3 + x + 1 + x**2) == "x^{3} + x^{2} + x + 1"
assert latex(2*x*y) == "2 x y"
assert latex(2*x*y, mul_symbol='dot') == r"2 \cdot x \cdot y"
assert latex(3*x**2*y, mul_symbol='\\,') == r"3\,x^{2}\,y"
assert latex(1.5*3**x, mul_symbol='\\,') == r"1.5 \cdot 3^{x}"
assert latex(1/x) == r"\frac{1}{x}"
assert latex(1/x, fold_short_frac=True) == "1 / x"
assert latex(-S(3)/2) == r"- \frac{3}{2}"
assert latex(-S(3)/2, fold_short_frac=True) == r"- 3 / 2"
assert latex(1/x**2) == r"\frac{1}{x^{2}}"
assert latex(1/(x + y)/2) == r"\frac{1}{2 \left(x + y\right)}"
assert latex(x/2) == r"\frac{x}{2}"
assert latex(x/2, fold_short_frac=True) == "x / 2"
assert latex((x + y)/(2*x)) == r"\frac{x + y}{2 x}"
assert latex((x + y)/(2*x), fold_short_frac=True) == \
r"\left(x + y\right) / 2 x"
assert latex((x + y)/(2*x), long_frac_ratio=0) == \
r"\frac{1}{2 x} \left(x + y\right)"
assert latex((x + y)/x) == r"\frac{x + y}{x}"
assert latex((x + y)/x, long_frac_ratio=3) == r"\frac{x + y}{x}"
assert latex((2*sqrt(2)*x)/3) == r"\frac{2 \sqrt{2} x}{3}"
assert latex((2*sqrt(2)*x)/3, long_frac_ratio=2) == \
r"\frac{2 x}{3} \sqrt{2}"
assert latex(2*Integral(x, x)/3) == r"\frac{2 \int x\, dx}{3}"
assert latex(2*Integral(x, x)/3, fold_short_frac=True) == \
r"\left(2 \int x\, dx\right) / 3"
assert latex(sqrt(x)) == r"\sqrt{x}"
assert latex(x**Rational(1, 3)) == r"\sqrt[3]{x}"
assert latex(sqrt(x)**3) == r"x^{\frac{3}{2}}"
assert latex(sqrt(x), itex=True) == r"\sqrt{x}"
assert latex(x**Rational(1, 3), itex=True) == r"\root{3}{x}"
assert latex(sqrt(x)**3, itex=True) == r"x^{\frac{3}{2}}"
assert latex(x**Rational(3, 4)) == r"x^{\frac{3}{4}}"
assert latex(x**Rational(3, 4), fold_frac_powers=True) == "x^{3/4}"
assert latex((x + 1)**Rational(3, 4)) == \
r"\left(x + 1\right)^{\frac{3}{4}}"
assert latex((x + 1)**Rational(3, 4), fold_frac_powers=True) == \
r"\left(x + 1\right)^{3/4}"
assert latex(1.5e20*x) == r"1.5 \cdot 10^{20} x"
assert latex(1.5e20*x, mul_symbol='dot') == r"1.5 \cdot 10^{20} \cdot x"
assert latex(1.5e20*x, mul_symbol='times') == r"1.5 \times 10^{20} \times x"
assert latex(1/sin(x)) == r"\frac{1}{\sin{\left (x \right )}}"
assert latex(sin(x)**-1) == r"\frac{1}{\sin{\left (x \right )}}"
assert latex(sin(x)**Rational(3, 2)) == \
r"\sin^{\frac{3}{2}}{\left (x \right )}"
assert latex(sin(x)**Rational(3, 2), fold_frac_powers=True) == \
r"\sin^{3/2}{\left (x \right )}"
assert latex(~x) == r"\neg x"
assert latex(x & y) == r"x \wedge y"
assert latex(x & y & z) == r"x \wedge y \wedge z"
assert latex(x | y) == r"x \vee y"
assert latex(x | y | z) == r"x \vee y \vee z"
assert latex((x & y) | z) == r"z \vee \left(x \wedge y\right)"
assert latex(Implies(x, y)) == r"x \Rightarrow y"
assert latex(~(x >> ~y)) == r"x \not\Rightarrow \neg y"
assert latex(Implies(Or(x,y), z)) == r"\left(x \vee y\right) \Rightarrow z"
assert latex(Implies(z, Or(x,y))) == r"z \Rightarrow \left(x \vee y\right)"
assert latex(~x, symbol_names={x: "x_i"}) == r"\neg x_i"
assert latex(x & y, symbol_names={x: "x_i", y: "y_i"}) == \
r"x_i \wedge y_i"
assert latex(x & y & z, symbol_names={x: "x_i", y: "y_i", z: "z_i"}) == \
r"x_i \wedge y_i \wedge z_i"
assert latex(x | y, symbol_names={x: "x_i", y: "y_i"}) == r"x_i \vee y_i"
assert latex(x | y | z, symbol_names={x: "x_i", y: "y_i", z: "z_i"}) == \
r"x_i \vee y_i \vee z_i"
assert latex((x & y) | z, symbol_names={x: "x_i", y: "y_i", z: "z_i"}) == \
r"z_i \vee \left(x_i \wedge y_i\right)"
assert latex(Implies(x, y), symbol_names={x: "x_i", y: "y_i"}) == \
r"x_i \Rightarrow y_i"
p = Symbol('p', positive=True)
assert latex(exp(-p)*log(p)) == r"e^{- p} \log{\left (p \right )}"
def test_latex_builtins():
assert latex(True) == r"\mathrm{True}"
assert latex(False) == r"\mathrm{False}"
assert latex(None) == r"\mathrm{None}"
assert latex(true) == r"\mathrm{True}"
assert latex(false) == r'\mathrm{False}'
def test_latex_SingularityFunction():
assert latex(SingularityFunction(x, 4, 5)) == r"{\langle x - 4 \rangle}^{5}"
assert latex(SingularityFunction(x, -3, 4)) == r"{\langle x + 3 \rangle}^{4}"
assert latex(SingularityFunction(x, 0, 4)) == r"{\langle x \rangle}^{4}"
assert latex(SingularityFunction(x, a, n)) == r"{\langle - a + x \rangle}^{n}"
assert latex(SingularityFunction(x, 4, -2)) == r"{\langle x - 4 \rangle}^{-2}"
assert latex(SingularityFunction(x, 4, -1)) == r"{\langle x - 4 \rangle}^{-1}"
def test_latex_cycle():
assert latex(Cycle(1, 2, 4)) == r"\left( 1\; 2\; 4\right)"
assert latex(Cycle(1, 2)(4, 5, 6)) == r"\left( 1\; 2\right)\left( 4\; 5\; 6\right)"
assert latex(Cycle()) == r"\left( \right)"
def test_latex_permutation():
assert latex(Permutation(1, 2, 4)) == r"\left( 1\; 2\; 4\right)"
assert latex(Permutation(1, 2)(4, 5, 6)) == r"\left( 1\; 2\right)\left( 4\; 5\; 6\right)"
assert latex(Permutation()) == r"\left( \right)"
assert latex(Permutation(2, 4)*Permutation(5)) == r"\left( 2\; 4\right)\left( 5\right)"
assert latex(Permutation(5)) == r"\left( 5\right)"
def test_latex_Float():
assert latex(Float(1.0e100)) == r"1.0 \cdot 10^{100}"
assert latex(Float(1.0e-100)) == r"1.0 \cdot 10^{-100}"
assert latex(Float(1.0e-100), mul_symbol="times") == r"1.0 \times 10^{-100}"
assert latex(1.0*oo) == r"\infty"
assert latex(-1.0*oo) == r"- \infty"
def test_latex_vector_expressions():
A = CoordSys3D('A')
assert latex(Cross(A.i, A.j*A.x*3+A.k)) == r"\mathbf{\hat{i}_{A}} \times \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}} + \mathbf{\hat{k}_{A}}\right)"
assert latex(Cross(A.i, A.j)) == r"\mathbf{\hat{i}_{A}} \times \mathbf{\hat{j}_{A}}"
assert latex(x*Cross(A.i, A.j)) == r"x \left(\mathbf{\hat{i}_{A}} \times \mathbf{\hat{j}_{A}}\right)"
assert latex(Cross(x*A.i, A.j)) == r'- \mathbf{\hat{j}_{A}} \times \left((x)\mathbf{\hat{i}_{A}}\right)'
assert latex(Curl(3*A.x*A.j)) == r"\nabla\times \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)"
assert latex(Curl(3*A.x*A.j+A.i)) == r"\nabla\times \left(\mathbf{\hat{i}_{A}} + (3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)"
assert latex(Curl(3*x*A.x*A.j)) == r"\nabla\times \left((3 \mathbf{{x}_{A}} x)\mathbf{\hat{j}_{A}}\right)"
assert latex(x*Curl(3*A.x*A.j)) == r"x \left(\nabla\times \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)\right)"
assert latex(Divergence(3*A.x*A.j+A.i)) == r"\nabla\cdot \left(\mathbf{\hat{i}_{A}} + (3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)"
assert latex(Divergence(3*A.x*A.j)) == r"\nabla\cdot \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)"
assert latex(x*Divergence(3*A.x*A.j)) == r"x \left(\nabla\cdot \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}}\right)\right)"
assert latex(Dot(A.i, A.j*A.x*3+A.k)) == r"\mathbf{\hat{i}_{A}} \cdot \left((3 \mathbf{{x}_{A}})\mathbf{\hat{j}_{A}} + \mathbf{\hat{k}_{A}}\right)"
assert latex(Dot(A.i, A.j)) == r"\mathbf{\hat{i}_{A}} \cdot \mathbf{\hat{j}_{A}}"
assert latex(Dot(x*A.i, A.j)) == r"\mathbf{\hat{j}_{A}} \cdot \left((x)\mathbf{\hat{i}_{A}}\right)"
assert latex(x*Dot(A.i, A.j)) == r"x \left(\mathbf{\hat{i}_{A}} \cdot \mathbf{\hat{j}_{A}}\right)"
assert latex(Gradient(A.x)) == r"\nabla\cdot \mathbf{{x}_{A}}"
assert latex(Gradient(A.x + 3*A.y)) == r"\nabla\cdot \left(\mathbf{{x}_{A}} + 3 \mathbf{{y}_{A}}\right)"
assert latex(x*Gradient(A.x)) == r"x \left(\nabla\cdot \mathbf{{x}_{A}}\right)"
assert latex(Gradient(x*A.x)) == r"\nabla\cdot \left(\mathbf{{x}_{A}} x\right)"
def test_latex_symbols():
Gamma, lmbda, rho = symbols('Gamma, lambda, rho')
tau, Tau, TAU, taU = symbols('tau, Tau, TAU, taU')
assert latex(tau) == r"\tau"
assert latex(Tau) == "T"
assert latex(TAU) == r"\tau"
assert latex(taU) == r"\tau"
# Check that all capitalized greek letters are handled explicitly
capitalized_letters = set(l.capitalize() for l in greek_letters_set)
assert len(capitalized_letters - set(tex_greek_dictionary.keys())) == 0
assert latex(Gamma + lmbda) == r"\Gamma + \lambda"
assert latex(Gamma * lmbda) == r"\Gamma \lambda"
assert latex(Symbol('q1')) == r"q_{1}"
assert latex(Symbol('q21')) == r"q_{21}"
assert latex(Symbol('epsilon0')) == r"\epsilon_{0}"
assert latex(Symbol('omega1')) == r"\omega_{1}"
assert latex(Symbol('91')) == r"91"
assert latex(Symbol('alpha_new')) == r"\alpha_{new}"
assert latex(Symbol('C^orig')) == r"C^{orig}"
assert latex(Symbol('x^alpha')) == r"x^{\alpha}"
assert latex(Symbol('beta^alpha')) == r"\beta^{\alpha}"
assert latex(Symbol('e^Alpha')) == r"e^{A}"
assert latex(Symbol('omega_alpha^beta')) == r"\omega^{\beta}_{\alpha}"
assert latex(Symbol('omega') ** Symbol('beta')) == r"\omega^{\beta}"
@XFAIL
def test_latex_symbols_failing():
rho, mass, volume = symbols('rho, mass, volume')
assert latex(
volume * rho == mass) == r"\rho \mathrm{volume} = \mathrm{mass}"
assert latex(volume / mass * rho == 1) == r"\rho \mathrm{volume} {\mathrm{mass}}^{(-1)} = 1"
assert latex(mass**3 * volume**3) == r"{\mathrm{mass}}^{3} \cdot {\mathrm{volume}}^{3}"
def test_latex_functions():
assert latex(exp(x)) == "e^{x}"
assert latex(exp(1) + exp(2)) == "e + e^{2}"
f = Function('f')
assert latex(f(x)) == r'f{\left (x \right )}'
assert latex(f) == r'f'
g = Function('g')
assert latex(g(x, y)) == r'g{\left (x,y \right )}'
assert latex(g) == r'g'
h = Function('h')
assert latex(h(x, y, z)) == r'h{\left (x,y,z \right )}'
assert latex(h) == r'h'
Li = Function('Li')
assert latex(Li) == r'\operatorname{Li}'
assert latex(Li(x)) == r'\operatorname{Li}{\left (x \right )}'
mybeta = Function('beta')
# not to be confused with the beta function
assert latex(mybeta(x, y, z)) == r"\beta{\left (x,y,z \right )}"
assert latex(beta(x, y)) == r'\operatorname{B}\left(x, y\right)'
assert latex(mybeta(x)) == r"\beta{\left (x \right )}"
assert latex(mybeta) == r"\beta"
g = Function('gamma')
# not to be confused with the gamma function
assert latex(g(x, y, z)) == r"\gamma{\left (x,y,z \right )}"
assert latex(g(x)) == r"\gamma{\left (x \right )}"
assert latex(g) == r"\gamma"
a1 = Function('a_1')
assert latex(a1) == r"\operatorname{a_{1}}"
assert latex(a1(x)) == r"\operatorname{a_{1}}{\left (x \right )}"
# issue 5868
omega1 = Function('omega1')
assert latex(omega1) == r"\omega_{1}"
assert latex(omega1(x)) == r"\omega_{1}{\left (x \right )}"
assert latex(sin(x)) == r"\sin{\left (x \right )}"
assert latex(sin(x), fold_func_brackets=True) == r"\sin {x}"
assert latex(sin(2*x**2), fold_func_brackets=True) == \
r"\sin {2 x^{2}}"
assert latex(sin(x**2), fold_func_brackets=True) == \
r"\sin {x^{2}}"
assert latex(asin(x)**2) == r"\operatorname{asin}^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="full") == \
r"\arcsin^{2}{\left (x \right )}"
assert latex(asin(x)**2, inv_trig_style="power") == \
r"\sin^{-1}{\left (x \right )}^{2}"
assert latex(asin(x**2), inv_trig_style="power",
fold_func_brackets=True) == \
r"\sin^{-1} {x^{2}}"
assert latex(acsc(x), inv_trig_style="full") == \
r"\operatorname{arccsc}{\left (x \right )}"
assert latex(factorial(k)) == r"k!"
assert latex(factorial(-k)) == r"\left(- k\right)!"
assert latex(subfactorial(k)) == r"!k"
assert latex(subfactorial(-k)) == r"!\left(- k\right)"
assert latex(factorial2(k)) == r"k!!"
assert latex(factorial2(-k)) == r"\left(- k\right)!!"
assert latex(binomial(2, k)) == r"{\binom{2}{k}}"
assert latex(FallingFactorial(3, k)) == r"{\left(3\right)}_{k}"
assert latex(RisingFactorial(3, k)) == r"{3}^{\left(k\right)}"
assert latex(floor(x)) == r"\lfloor{x}\rfloor"
assert latex(ceiling(x)) == r"\lceil{x}\rceil"
assert latex(Min(x, 2, x**3)) == r"\min\left(2, x, x^{3}\right)"
assert latex(Min(x, y)**2) == r"\min\left(x, y\right)^{2}"
assert latex(Max(x, 2, x**3)) == r"\max\left(2, x, x^{3}\right)"
assert latex(Max(x, y)**2) == r"\max\left(x, y\right)^{2}"
assert latex(Abs(x)) == r"\left|{x}\right|"
assert latex(re(x)) == r"\Re{\left(x\right)}"
assert latex(re(x + y)) == r"\Re{\left(x\right)} + \Re{\left(y\right)}"
assert latex(im(x)) == r"\Im{x}"
assert latex(conjugate(x)) == r"\overline{x}"
assert latex(gamma(x)) == r"\Gamma\left(x\right)"
w = Wild('w')
assert latex(gamma(w)) == r"\Gamma\left(w\right)"
assert latex(Order(x)) == r"O\left(x\right)"
assert latex(Order(x, x)) == r"O\left(x\right)"
assert latex(Order(x, (x, 0))) == r"O\left(x\right)"
assert latex(Order(x, (x, oo))) == r"O\left(x; x\rightarrow \infty\right)"
assert latex(Order(x - y, (x, y))) == r"O\left(x - y; x\rightarrow y\right)"
assert latex(Order(x, x, y)) == r"O\left(x; \left ( x, \quad y\right )\rightarrow \left ( 0, \quad 0\right )\right)"
assert latex(Order(x, x, y)) == r"O\left(x; \left ( x, \quad y\right )\rightarrow \left ( 0, \quad 0\right )\right)"
assert latex(Order(x, (x, oo), (y, oo))) == r"O\left(x; \left ( x, \quad y\right )\rightarrow \left ( \infty, \quad \infty\right )\right)"
assert latex(lowergamma(x, y)) == r'\gamma\left(x, y\right)'
assert latex(uppergamma(x, y)) == r'\Gamma\left(x, y\right)'
assert latex(cot(x)) == r'\cot{\left (x \right )}'
assert latex(coth(x)) == r'\coth{\left (x \right )}'
assert latex(re(x)) == r'\Re{\left(x\right)}'
assert latex(im(x)) == r'\Im{x}'
assert latex(root(x, y)) == r'x^{\frac{1}{y}}'
assert latex(arg(x)) == r'\arg{\left (x \right )}'
assert latex(zeta(x)) == r'\zeta\left(x\right)'
assert latex(zeta(x)) == r"\zeta\left(x\right)"
assert latex(zeta(x)**2) == r"\zeta^{2}\left(x\right)"
assert latex(zeta(x, y)) == r"\zeta\left(x, y\right)"
assert latex(zeta(x, y)**2) == r"\zeta^{2}\left(x, y\right)"
assert latex(dirichlet_eta(x)) == r"\eta\left(x\right)"
assert latex(dirichlet_eta(x)**2) == r"\eta^{2}\left(x\right)"
assert latex(polylog(x, y)) == r"\operatorname{Li}_{x}\left(y\right)"
assert latex(
polylog(x, y)**2) == r"\operatorname{Li}_{x}^{2}\left(y\right)"
assert latex(lerchphi(x, y, n)) == r"\Phi\left(x, y, n\right)"
assert latex(lerchphi(x, y, n)**2) == r"\Phi^{2}\left(x, y, n\right)"
assert latex(elliptic_k(z)) == r"K\left(z\right)"
assert latex(elliptic_k(z)**2) == r"K^{2}\left(z\right)"
assert latex(elliptic_f(x, y)) == r"F\left(x\middle| y\right)"
assert latex(elliptic_f(x, y)**2) == r"F^{2}\left(x\middle| y\right)"
assert latex(elliptic_e(x, y)) == r"E\left(x\middle| y\right)"
assert latex(elliptic_e(x, y)**2) == r"E^{2}\left(x\middle| y\right)"
assert latex(elliptic_e(z)) == r"E\left(z\right)"
assert latex(elliptic_e(z)**2) == r"E^{2}\left(z\right)"
assert latex(elliptic_pi(x, y, z)) == r"\Pi\left(x; y\middle| z\right)"
assert latex(elliptic_pi(x, y, z)**2) == \
r"\Pi^{2}\left(x; y\middle| z\right)"
assert latex(elliptic_pi(x, y)) == r"\Pi\left(x\middle| y\right)"
assert latex(elliptic_pi(x, y)**2) == r"\Pi^{2}\left(x\middle| y\right)"
assert latex(Ei(x)) == r'\operatorname{Ei}{\left (x \right )}'
assert latex(Ei(x)**2) == r'\operatorname{Ei}^{2}{\left (x \right )}'
assert latex(expint(x, y)**2) == r'\operatorname{E}_{x}^{2}\left(y\right)'
assert latex(Shi(x)**2) == r'\operatorname{Shi}^{2}{\left (x \right )}'
assert latex(Si(x)**2) == r'\operatorname{Si}^{2}{\left (x \right )}'
assert latex(Ci(x)**2) == r'\operatorname{Ci}^{2}{\left (x \right )}'
assert latex(Chi(x)**2) == r'\operatorname{Chi}^{2}\left(x\right)'
assert latex(Chi(x)) == r'\operatorname{Chi}\left(x\right)'
assert latex(
jacobi(n, a, b, x)) == r'P_{n}^{\left(a,b\right)}\left(x\right)'
assert latex(jacobi(n, a, b, x)**2) == r'\left(P_{n}^{\left(a,b\right)}\left(x\right)\right)^{2}'
assert latex(
gegenbauer(n, a, x)) == r'C_{n}^{\left(a\right)}\left(x\right)'
assert latex(gegenbauer(n, a, x)**2) == r'\left(C_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(chebyshevt(n, x)) == r'T_{n}\left(x\right)'
assert latex(
chebyshevt(n, x)**2) == r'\left(T_{n}\left(x\right)\right)^{2}'
assert latex(chebyshevu(n, x)) == r'U_{n}\left(x\right)'
assert latex(
chebyshevu(n, x)**2) == r'\left(U_{n}\left(x\right)\right)^{2}'
assert latex(legendre(n, x)) == r'P_{n}\left(x\right)'
assert latex(legendre(n, x)**2) == r'\left(P_{n}\left(x\right)\right)^{2}'
assert latex(
assoc_legendre(n, a, x)) == r'P_{n}^{\left(a\right)}\left(x\right)'
assert latex(assoc_legendre(n, a, x)**2) == r'\left(P_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(laguerre(n, x)) == r'L_{n}\left(x\right)'
assert latex(laguerre(n, x)**2) == r'\left(L_{n}\left(x\right)\right)^{2}'
assert latex(
assoc_laguerre(n, a, x)) == r'L_{n}^{\left(a\right)}\left(x\right)'
assert latex(assoc_laguerre(n, a, x)**2) == r'\left(L_{n}^{\left(a\right)}\left(x\right)\right)^{2}'
assert latex(hermite(n, x)) == r'H_{n}\left(x\right)'
assert latex(hermite(n, x)**2) == r'\left(H_{n}\left(x\right)\right)^{2}'
theta = Symbol("theta", real=True)
phi = Symbol("phi", real=True)
assert latex(Ynm(n,m,theta,phi)) == r'Y_{n}^{m}\left(\theta,\phi\right)'
assert latex(Ynm(n, m, theta, phi)**3) == r'\left(Y_{n}^{m}\left(\theta,\phi\right)\right)^{3}'
assert latex(Znm(n,m,theta,phi)) == r'Z_{n}^{m}\left(\theta,\phi\right)'
assert latex(Znm(n, m, theta, phi)**3) == r'\left(Z_{n}^{m}\left(\theta,\phi\right)\right)^{3}'
# Test latex printing of function names with "_"
assert latex(
polar_lift(0)) == r"\operatorname{polar\_lift}{\left (0 \right )}"
assert latex(polar_lift(
0)**3) == r"\operatorname{polar\_lift}^{3}{\left (0 \right )}"
assert latex(totient(n)) == r'\phi\left(n\right)'
assert latex(totient(n) ** 2) == r'\left(\phi\left(n\right)\right)^{2}'
assert latex(reduced_totient(n)) == r'\lambda\left(n\right)'
assert latex(reduced_totient(n) ** 2) == r'\left(\lambda\left(n\right)\right)^{2}'
assert latex(divisor_sigma(x)) == r"\sigma\left(x\right)"
assert latex(divisor_sigma(x)**2) == r"\sigma^{2}\left(x\right)"
assert latex(divisor_sigma(x, y)) == r"\sigma_y\left(x\right)"
assert latex(divisor_sigma(x, y)**2) == r"\sigma^{2}_y\left(x\right)"
assert latex(udivisor_sigma(x)) == r"\sigma^*\left(x\right)"
assert latex(udivisor_sigma(x)**2) == r"\sigma^*^{2}\left(x\right)"
assert latex(udivisor_sigma(x, y)) == r"\sigma^*_y\left(x\right)"
assert latex(udivisor_sigma(x, y)**2) == r"\sigma^*^{2}_y\left(x\right)"
assert latex(primenu(n)) == r'\nu\left(n\right)'
assert latex(primenu(n) ** 2) == r'\left(\nu\left(n\right)\right)^{2}'
assert latex(primeomega(n)) == r'\Omega\left(n\right)'
assert latex(primeomega(n) ** 2) == r'\left(\Omega\left(n\right)\right)^{2}'
assert latex(Mod(x, 7)) == r'x\bmod{7}'
assert latex(Mod(x + 1, 7)) == r'\left(x + 1\right)\bmod{7}'
assert latex(Mod(2 * x, 7)) == r'2 x\bmod{7}'
assert latex(Mod(x, 7) + 1) == r'\left(x\bmod{7}\right) + 1'
assert latex(2 * Mod(x, 7)) == r'2 \left(x\bmod{7}\right)'
# some unknown function name should get rendered with \operatorname
fjlkd = Function('fjlkd')
assert latex(fjlkd(x)) == r'\operatorname{fjlkd}{\left (x \right )}'
# even when it is referred to without an argument
assert latex(fjlkd) == r'\operatorname{fjlkd}'
# test that notation passes to subclasses of the same name only
def test_function_subclass_different_name():
class mygamma(gamma):
pass
assert latex(mygamma) == r"\operatorname{mygamma}"
assert latex(mygamma(x)) == r"\operatorname{mygamma}{\left (x \right )}"
def test_hyper_printing():
from sympy import pi
from sympy.abc import x, z
assert latex(meijerg(Tuple(pi, pi, x), Tuple(1),
(0, 1), Tuple(1, 2, 3/pi), z)) == \
r'{G_{4, 5}^{2, 3}\left(\begin{matrix} \pi, \pi, x & 1 \\0, 1 & 1, 2, \frac{3}{\pi} \end{matrix} \middle| {z} \right)}'
assert latex(meijerg(Tuple(), Tuple(1), (0,), Tuple(), z)) == \
r'{G_{1, 1}^{1, 0}\left(\begin{matrix} & 1 \\0 & \end{matrix} \middle| {z} \right)}'
assert latex(hyper((x, 2), (3,), z)) == \
r'{{}_{2}F_{1}\left(\begin{matrix} x, 2 ' \
r'\\ 3 \end{matrix}\middle| {z} \right)}'
assert latex(hyper(Tuple(), Tuple(1), z)) == \
r'{{}_{0}F_{1}\left(\begin{matrix} ' \
r'\\ 1 \end{matrix}\middle| {z} \right)}'
def test_latex_bessel():
from sympy.functions.special.bessel import (besselj, bessely, besseli,
besselk, hankel1, hankel2, jn, yn, hn1, hn2)
from sympy.abc import z
assert latex(besselj(n, z**2)**k) == r'J^{k}_{n}\left(z^{2}\right)'
assert latex(bessely(n, z)) == r'Y_{n}\left(z\right)'
assert latex(besseli(n, z)) == r'I_{n}\left(z\right)'
assert latex(besselk(n, z)) == r'K_{n}\left(z\right)'
assert latex(hankel1(n, z**2)**2) == \
r'\left(H^{(1)}_{n}\left(z^{2}\right)\right)^{2}'
assert latex(hankel2(n, z)) == r'H^{(2)}_{n}\left(z\right)'
assert latex(jn(n, z)) == r'j_{n}\left(z\right)'
assert latex(yn(n, z)) == r'y_{n}\left(z\right)'
assert latex(hn1(n, z)) == r'h^{(1)}_{n}\left(z\right)'
assert latex(hn2(n, z)) == r'h^{(2)}_{n}\left(z\right)'
def test_latex_fresnel():
from sympy.functions.special.error_functions import (fresnels, fresnelc)
from sympy.abc import z
assert latex(fresnels(z)) == r'S\left(z\right)'
assert latex(fresnelc(z)) == r'C\left(z\right)'
assert latex(fresnels(z)**2) == r'S^{2}\left(z\right)'
assert latex(fresnelc(z)**2) == r'C^{2}\left(z\right)'
def test_latex_brackets():
assert latex((-1)**x) == r"\left(-1\right)^{x}"
def test_latex_indexed():
Psi_symbol = Symbol('Psi_0', complex=True, real=False)
Psi_indexed = IndexedBase(Symbol('Psi', complex=True, real=False))
symbol_latex = latex(Psi_symbol * conjugate(Psi_symbol))
indexed_latex = latex(Psi_indexed[0] * conjugate(Psi_indexed[0]))
# \\overline{{\\Psi}_{0}} {\\Psi}_{0} vs. \\Psi_{0} \\overline{\\Psi_{0}}
assert symbol_latex == '\\Psi_{0} \\overline{\\Psi_{0}}'
assert indexed_latex == '\\overline{{\\Psi}_{0}} {\\Psi}_{0}'
# Symbol('gamma') gives r'\gamma'
assert latex(Indexed('x1',Symbol('i'))) == '{x_{1}}_{i}'
assert latex(IndexedBase('gamma')) == r'\gamma'
assert latex(IndexedBase('a b')) == 'a b'
assert latex(IndexedBase('a_b')) == 'a_{b}'
def test_latex_derivatives():
# regular "d" for ordinary derivatives
assert latex(diff(x**3, x, evaluate=False)) == \
r"\frac{d}{d x} x^{3}"
assert latex(diff(sin(x) + x**2, x, evaluate=False)) == \
r"\frac{d}{d x} \left(x^{2} + \sin{\left (x \right )}\right)"
assert latex(diff(diff(sin(x) + x**2, x, evaluate=False), evaluate=False)) == \
r"\frac{d^{2}}{d x^{2}} \left(x^{2} + \sin{\left (x \right )}\right)"
assert latex(diff(diff(diff(sin(x) + x**2, x, evaluate=False), evaluate=False), evaluate=False)) == \
r"\frac{d^{3}}{d x^{3}} \left(x^{2} + \sin{\left (x \right )}\right)"
# \partial for partial derivatives
assert latex(diff(sin(x * y), x, evaluate=False)) == \
r"\frac{\partial}{\partial x} \sin{\left (x y \right )}"
assert latex(diff(sin(x * y) + x**2, x, evaluate=False)) == \
r"\frac{\partial}{\partial x} \left(x^{2} + \sin{\left (x y \right )}\right)"
assert latex(diff(diff(sin(x*y) + x**2, x, evaluate=False), x, evaluate=False)) == \
r"\frac{\partial^{2}}{\partial x^{2}} \left(x^{2} + \sin{\left (x y \right )}\right)"
assert latex(diff(diff(diff(sin(x*y) + x**2, x, evaluate=False), x, evaluate=False), x, evaluate=False)) == \
r"\frac{\partial^{3}}{\partial x^{3}} \left(x^{2} + \sin{\left (x y \right )}\right)"
# mixed partial derivatives
f = Function("f")
assert latex(diff(diff(f(x,y), x, evaluate=False), y, evaluate=False)) == \
r"\frac{\partial^{2}}{\partial y\partial x} " + latex(f(x,y))
assert latex(diff(diff(diff(f(x,y), x, evaluate=False), x, evaluate=False), y, evaluate=False)) == \
r"\frac{\partial^{3}}{\partial y\partial x^{2}} " + latex(f(x,y))
# use ordinary d when one of the variables has been integrated out
assert latex(diff(Integral(exp(-x * y), (x, 0, oo)), y, evaluate=False)) == \
r"\frac{d}{d y} \int\limits_{0}^{\infty} e^{- x y}\, dx"
# Derivative wrapped in power:
assert latex(diff(x, x, evaluate=False)**2) == \
r"\left(\frac{d}{d x} x\right)^{2}"
assert latex(diff(f(x), x)**2) == \
r"\left(\frac{d}{d x} f{\left (x \right )}\right)^{2}"
assert latex(diff(f(x), (x, n))) == \
r"\frac{d^{n}}{d x^{n}} f{\left (x \right )}"
def test_latex_subs():
assert latex(Subs(x*y, (
x, y), (1, 2))) == r'\left. x y \right|_{\substack{ x=1\\ y=2 }}'
def test_latex_integrals():
assert latex(Integral(log(x), x)) == r"\int \log{\left (x \right )}\, dx"
assert latex(Integral(x**2, (x, 0, 1))) == r"\int\limits_{0}^{1} x^{2}\, dx"
assert latex(Integral(x**2, (x, 10, 20))) == r"\int\limits_{10}^{20} x^{2}\, dx"
assert latex(Integral(
y*x**2, (x, 0, 1), y)) == r"\int\int\limits_{0}^{1} x^{2} y\, dx\, dy"
assert latex(Integral(y*x**2, (x, 0, 1), y), mode='equation*') \
== r"\begin{equation*}\int\int\limits_{0}^{1} x^{2} y\, dx\, dy\end{equation*}"
assert latex(Integral(y*x**2, (x, 0, 1), y), mode='equation*', itex=True) \
== r"$$\int\int_{0}^{1} x^{2} y\, dx\, dy$$"
assert latex(Integral(x, (x, 0))) == r"\int\limits^{0} x\, dx"
assert latex(Integral(x*y, x, y)) == r"\iint x y\, dx\, dy"
assert latex(Integral(x*y*z, x, y, z)) == r"\iiint x y z\, dx\, dy\, dz"
assert latex(Integral(x*y*z*t, x, y, z, t)) == \
r"\iiiint t x y z\, dx\, dy\, dz\, dt"
assert latex(Integral(x, x, x, x, x, x, x)) == \
r"\int\int\int\int\int\int x\, dx\, dx\, dx\, dx\, dx\, dx"
assert latex(Integral(x, x, y, (z, 0, 1))) == \
r"\int\limits_{0}^{1}\int\int x\, dx\, dy\, dz"
# fix issue #10806
assert latex(Integral(z, z)**2) == r"\left(\int z\, dz\right)^{2}"
assert latex(Integral(x + z, z)) == r"\int \left(x + z\right)\, dz"
assert latex(Integral(x+z/2, z)) == r"\int \left(x + \frac{z}{2}\right)\, dz"
assert latex(Integral(x**y, z)) == r"\int x^{y}\, dz"
def test_latex_sets():
for s in (frozenset, set):
assert latex(s([x*y, x**2])) == r"\left\{x^{2}, x y\right\}"
assert latex(s(range(1, 6))) == r"\left\{1, 2, 3, 4, 5\right\}"
assert latex(s(range(1, 13))) == \
r"\left\{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12\right\}"
s = FiniteSet
assert latex(s(*[x*y, x**2])) == r"\left\{x^{2}, x y\right\}"
assert latex(s(*range(1, 6))) == r"\left\{1, 2, 3, 4, 5\right\}"
assert latex(s(*range(1, 13))) == \
r"\left\{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12\right\}"
def test_latex_SetExpr():
iv = Interval(1, 3)
se = SetExpr(iv)
assert latex(se) == r"SetExpr\left(\left[1, 3\right]\right)"
def test_latex_Range():
assert latex(Range(1, 51)) == \
r'\left\{1, 2, \ldots, 50\right\}'
assert latex(Range(1, 4)) == r'\left\{1, 2, 3\right\}'
assert latex(Range(0, 3, 1)) == r'\left\{0, 1, 2\right\}'
assert latex(Range(0, 30, 1)) == r'\left\{0, 1, \ldots, 29\right\}'
assert latex(Range(30, 1, -1)) == r'\left\{30, 29, \ldots, 2\right\}'
assert latex(Range(0, oo, 2)) == r'\left\{0, 2, \ldots, \infty\right\}'
assert latex(Range(oo, -2, -2)) == r'\left\{\infty, \ldots, 2, 0\right\}'
assert latex(Range(-2, -oo, -1)) == r'\left\{-2, -3, \ldots, -\infty\right\}'
def test_latex_sequences():
s1 = SeqFormula(a**2, (0, oo))
s2 = SeqPer((1, 2))
latex_str = r'\left[0, 1, 4, 9, \ldots\right]'
assert latex(s1) == latex_str
latex_str = r'\left[1, 2, 1, 2, \ldots\right]'
assert latex(s2) == latex_str
s3 = SeqFormula(a**2, (0, 2))
s4 = SeqPer((1, 2), (0, 2))
latex_str = r'\left[0, 1, 4\right]'
assert latex(s3) == latex_str
latex_str = r'\left[1, 2, 1\right]'
assert latex(s4) == latex_str
s5 = SeqFormula(a**2, (-oo, 0))
s6 = SeqPer((1, 2), (-oo, 0))
latex_str = r'\left[\ldots, 9, 4, 1, 0\right]'
assert latex(s5) == latex_str
latex_str = r'\left[\ldots, 2, 1, 2, 1\right]'
assert latex(s6) == latex_str
latex_str = r'\left[1, 3, 5, 11, \ldots\right]'
assert latex(SeqAdd(s1, s2)) == latex_str
latex_str = r'\left[1, 3, 5\right]'
assert latex(SeqAdd(s3, s4)) == latex_str
latex_str = r'\left[\ldots, 11, 5, 3, 1\right]'
assert latex(SeqAdd(s5, s6)) == latex_str
latex_str = r'\left[0, 2, 4, 18, \ldots\right]'
assert latex(SeqMul(s1, s2)) == latex_str
latex_str = r'\left[0, 2, 4\right]'
assert latex(SeqMul(s3, s4)) == latex_str
latex_str = r'\left[\ldots, 18, 4, 2, 0\right]'
assert latex(SeqMul(s5, s6)) == latex_str
def test_latex_FourierSeries():
latex_str = r'2 \sin{\left (x \right )} - \sin{\left (2 x \right )} + \frac{2 \sin{\left (3 x \right )}}{3} + \ldots'
assert latex(fourier_series(x, (x, -pi, pi))) == latex_str
def test_latex_FormalPowerSeries():
latex_str = r'\sum_{k=1}^{\infty} - \frac{\left(-1\right)^{- k} x^{k}}{k}'
assert latex(fps(log(1 + x))) == latex_str
def test_latex_intervals():
a = Symbol('a', real=True)
assert latex(Interval(0, 0)) == r"\left\{0\right\}"
assert latex(Interval(0, a)) == r"\left[0, a\right]"
assert latex(Interval(0, a, False, False)) == r"\left[0, a\right]"
assert latex(Interval(0, a, True, False)) == r"\left(0, a\right]"
assert latex(Interval(0, a, False, True)) == r"\left[0, a\right)"
assert latex(Interval(0, a, True, True)) == r"\left(0, a\right)"
def test_latex_AccumuBounds():
a = Symbol('a', real=True)
assert latex(AccumBounds(0, 1)) == r"\langle 0, 1\rangle"
assert latex(AccumBounds(0, a)) == r"\langle 0, a\rangle"
assert latex(AccumBounds(a + 1, a + 2)) == r"\langle a + 1, a + 2\rangle"
def test_latex_emptyset():
assert latex(S.EmptySet) == r"\emptyset"
def test_latex_commutator():
A = Operator('A')
B = Operator('B')
comm = Commutator(B, A)
assert latex(comm.doit()) == r"- (A B - B A)"
def test_latex_union():
assert latex(Union(Interval(0, 1), Interval(2, 3))) == \
r"\left[0, 1\right] \cup \left[2, 3\right]"
assert latex(Union(Interval(1, 1), Interval(2, 2), Interval(3, 4))) == \
r"\left\{1, 2\right\} \cup \left[3, 4\right]"
def test_latex_symmetric_difference():
assert latex(SymmetricDifference(Interval(2,5), Interval(4,7), \
evaluate = False)) == r'\left[2, 5\right] \triangle \left[4, 7\right]'
def test_latex_Complement():
assert latex(Complement(S.Reals, S.Naturals)) == r"\mathbb{R} \setminus \mathbb{N}"
def test_latex_Complexes():
assert latex(S.Complexes) == r"\mathbb{C}"
def test_latex_productset():
line = Interval(0, 1)
bigline = Interval(0, 10)
fset = FiniteSet(1, 2, 3)
assert latex(line**2) == r"%s^{2}" % latex(line)
assert latex(line**10) == r"%s^{10}" % latex(line)
assert latex(line * bigline * fset) == r"%s \times %s \times %s" % (
latex(line), latex(bigline), latex(fset))
def test_latex_Naturals():
assert latex(S.Naturals) == r"\mathbb{N}"
def test_latex_Naturals0():
assert latex(S.Naturals0) == r"\mathbb{N}_0"
def test_latex_Integers():
assert latex(S.Integers) == r"\mathbb{Z}"
def test_latex_ImageSet():
x = Symbol('x')
assert latex(ImageSet(Lambda(x, x**2), S.Naturals)) == \
r"\left\{x^{2}\; |\; x \in \mathbb{N}\right\}"
y = Symbol('y')
imgset = ImageSet(Lambda((x, y), x + y), {1, 2, 3}, {3, 4})
assert latex(imgset) == r"\left\{x + y\; |\; x \in \left\{1, 2, 3\right\}, y \in \left\{3, 4\right\}\right\}"
def test_latex_ConditionSet():
x = Symbol('x')
assert latex(ConditionSet(x, Eq(x**2, 1), S.Reals)) == \
r"\left\{x \mid x \in \mathbb{R} \wedge x^{2} = 1 \right\}"
assert latex(ConditionSet(x, Eq(x**2, 1), S.UniversalSet)) == \
r"\left\{x \mid x^{2} = 1 \right\}"
def test_latex_ComplexRegion():
assert latex(ComplexRegion(Interval(3, 5)*Interval(4, 6))) == \
r"\left\{x + y i\; |\; x, y \in \left[3, 5\right] \times \left[4, 6\right] \right\}"
assert latex(ComplexRegion(Interval(0, 1)*Interval(0, 2*pi), polar=True)) == \
r"\left\{r \left(i \sin{\left (\theta \right )} + \cos{\left (\theta \right )}\right)\; |\; r, \theta \in \left[0, 1\right] \times \left[0, 2 \pi\right) \right\}"
def test_latex_Contains():
x = Symbol('x')
assert latex(Contains(x, S.Naturals)) == r"x \in \mathbb{N}"
def test_latex_sum():
assert latex(Sum(x*y**2, (x, -2, 2), (y, -5, 5))) == \
r"\sum_{\substack{-2 \leq x \leq 2\\-5 \leq y \leq 5}} x y^{2}"
assert latex(Sum(x**2, (x, -2, 2))) == \
r"\sum_{x=-2}^{2} x^{2}"
assert latex(Sum(x**2 + y, (x, -2, 2))) == \
r"\sum_{x=-2}^{2} \left(x^{2} + y\right)"
assert latex(Sum(x**2 + y, (x, -2, 2))**2) == \
r"\left(\sum_{x=-2}^{2} \left(x^{2} + y\right)\right)^{2}"
def test_latex_product():
assert latex(Product(x*y**2, (x, -2, 2), (y, -5, 5))) == \
r"\prod_{\substack{-2 \leq x \leq 2\\-5 \leq y \leq 5}} x y^{2}"
assert latex(Product(x**2, (x, -2, 2))) == \
r"\prod_{x=-2}^{2} x^{2}"
assert latex(Product(x**2 + y, (x, -2, 2))) == \
r"\prod_{x=-2}^{2} \left(x^{2} + y\right)"
assert latex(Product(x, (x, -2, 2))**2) == \
r"\left(\prod_{x=-2}^{2} x\right)^{2}"
def test_latex_limits():
assert latex(Limit(x, x, oo)) == r"\lim_{x \to \infty} x"
# issue 8175
f = Function('f')
assert latex(Limit(f(x), x, 0)) == r"\lim_{x \to 0^+} f{\left (x \right )}"
assert latex(Limit(f(x), x, 0, "-")) == r"\lim_{x \to 0^-} f{\left (x \right )}"
# issue #10806
assert latex(Limit(f(x), x, 0)**2) == r"\left(\lim_{x \to 0^+} f{\left (x \right )}\right)^{2}"
# bi-directional limit
assert latex(Limit(f(x), x, 0, dir='+-')) == r"\lim_{x \to 0} f{\left (x \right )}"
def test_latex_log():
assert latex(log(x)) == r"\log{\left (x \right )}"
assert latex(ln(x)) == r"\log{\left (x \right )}"
assert latex(log(x), ln_notation=True) == r"\ln{\left (x \right )}"
assert latex(log(x)+log(y)) == r"\log{\left (x \right )} + \log{\left (y \right )}"
assert latex(log(x)+log(y), ln_notation=True) == r"\ln{\left (x \right )} + \ln{\left (y \right )}"
assert latex(pow(log(x),x)) == r"\log{\left (x \right )}^{x}"
assert latex(pow(log(x),x), ln_notation=True) == r"\ln{\left (x \right )}^{x}"
def test_issue_3568():
beta = Symbol(r'\beta')
y = beta + x
assert latex(y) in [r'\beta + x', r'x + \beta']
beta = Symbol(r'beta')
y = beta + x
assert latex(y) in [r'\beta + x', r'x + \beta']
def test_latex():
assert latex((2*tau)**Rational(7, 2)) == "8 \\sqrt{2} \\tau^{\\frac{7}{2}}"
assert latex((2*mu)**Rational(7, 2), mode='equation*') == \
"\\begin{equation*}8 \\sqrt{2} \\mu^{\\frac{7}{2}}\\end{equation*}"
assert latex((2*mu)**Rational(7, 2), mode='equation', itex=True) == \
"$$8 \\sqrt{2} \\mu^{\\frac{7}{2}}$$"
assert latex([2/x, y]) == r"\left [ \frac{2}{x}, \quad y\right ]"
def test_latex_dict():
d = {Rational(1): 1, x**2: 2, x: 3, x**3: 4}
assert latex(d) == r'\left \{ 1 : 1, \quad x : 3, \quad x^{2} : 2, \quad x^{3} : 4\right \}'
D = Dict(d)
assert latex(D) == r'\left \{ 1 : 1, \quad x : 3, \quad x^{2} : 2, \quad x^{3} : 4\right \}'
def test_latex_list():
l = [Symbol('omega1'), Symbol('a'), Symbol('alpha')]
assert latex(l) == r'\left [ \omega_{1}, \quad a, \quad \alpha\right ]'
def test_latex_rational():
#tests issue 3973
assert latex(-Rational(1, 2)) == "- \\frac{1}{2}"
assert latex(Rational(-1, 2)) == "- \\frac{1}{2}"
assert latex(Rational(1, -2)) == "- \\frac{1}{2}"
assert latex(-Rational(-1, 2)) == "\\frac{1}{2}"
assert latex(-Rational(1, 2)*x) == "- \\frac{x}{2}"
assert latex(-Rational(1, 2)*x + Rational(-2, 3)*y) == \
"- \\frac{x}{2} - \\frac{2 y}{3}"
def test_latex_inverse():
#tests issue 4129
assert latex(1/x) == "\\frac{1}{x}"
assert latex(1/(x + y)) == "\\frac{1}{x + y}"
def test_latex_DiracDelta():
assert latex(DiracDelta(x)) == r"\delta\left(x\right)"
assert latex(DiracDelta(x)**2) == r"\left(\delta\left(x\right)\right)^{2}"
assert latex(DiracDelta(x, 0)) == r"\delta\left(x\right)"
assert latex(DiracDelta(x, 5)) == \
r"\delta^{\left( 5 \right)}\left( x \right)"
assert latex(DiracDelta(x, 5)**2) == \
r"\left(\delta^{\left( 5 \right)}\left( x \right)\right)^{2}"
def test_latex_Heaviside():
assert latex(Heaviside(x)) == r"\theta\left(x\right)"
assert latex(Heaviside(x)**2) == r"\left(\theta\left(x\right)\right)^{2}"
def test_latex_KroneckerDelta():
assert latex(KroneckerDelta(x, y)) == r"\delta_{x y}"
assert latex(KroneckerDelta(x, y + 1)) == r"\delta_{x, y + 1}"
# issue 6578
assert latex(KroneckerDelta(x + 1, y)) == r"\delta_{y, x + 1}"
def test_latex_LeviCivita():
assert latex(LeviCivita(x, y, z)) == r"\varepsilon_{x y z}"
assert latex(LeviCivita(x, y, z)**2) == r"\left(\varepsilon_{x y z}\right)^{2}"
assert latex(LeviCivita(x, y, z + 1)) == r"\varepsilon_{x, y, z + 1}"
assert latex(LeviCivita(x, y + 1, z)) == r"\varepsilon_{x, y + 1, z}"
assert latex(LeviCivita(x + 1, y, z)) == r"\varepsilon_{x + 1, y, z}"
def test_mode():
expr = x + y
assert latex(expr) == 'x + y'
assert latex(expr, mode='plain') == 'x + y'
assert latex(expr, mode='inline') == '$x + y$'
assert latex(
expr, mode='equation*') == '\\begin{equation*}x + y\\end{equation*}'
assert latex(
expr, mode='equation') == '\\begin{equation}x + y\\end{equation}'
def test_latex_Piecewise():
p = Piecewise((x, x < 1), (x**2, True))
assert latex(p) == "\\begin{cases} x & \\text{for}\\: x < 1 \\\\x^{2} &" \
" \\text{otherwise} \\end{cases}"
assert latex(p, itex=True) == "\\begin{cases} x & \\text{for}\\: x \\lt 1 \\\\x^{2} &" \
" \\text{otherwise} \\end{cases}"
p = Piecewise((x, x < 0), (0, x >= 0))
assert latex(p) == '\\begin{cases} x & \\text{for}\\: x < 0 \\\\0 &' \
' \\text{otherwise} \\end{cases}'
A, B = symbols("A B", commutative=False)
p = Piecewise((A**2, Eq(A, B)), (A*B, True))
s = r"\begin{cases} A^{2} & \text{for}\: A = B \\A B & \text{otherwise} \end{cases}"
assert latex(p) == s
assert latex(A*p) == r"A \left(%s\right)" % s
assert latex(p*A) == r"\left(%s\right) A" % s
def test_latex_Matrix():
M = Matrix([[1 + x, y], [y, x - 1]])
assert latex(M) == \
r'\left[\begin{matrix}x + 1 & y\\y & x - 1\end{matrix}\right]'
assert latex(M, mode='inline') == \
r'$\left[\begin{smallmatrix}x + 1 & y\\' \
r'y & x - 1\end{smallmatrix}\right]$'
assert latex(M, mat_str='array') == \
r'\left[\begin{array}{cc}x + 1 & y\\y & x - 1\end{array}\right]'
assert latex(M, mat_str='bmatrix') == \
r'\left[\begin{bmatrix}x + 1 & y\\y & x - 1\end{bmatrix}\right]'
assert latex(M, mat_delim=None, mat_str='bmatrix') == \
r'\begin{bmatrix}x + 1 & y\\y & x - 1\end{bmatrix}'
M2 = Matrix(1, 11, range(11))
assert latex(M2) == \
r'\left[\begin{array}{ccccccccccc}' \
r'0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10\end{array}\right]'
def test_latex_matrix_with_functions():
t = symbols('t')
theta1 = symbols('theta1', cls=Function)
M = Matrix([[sin(theta1(t)), cos(theta1(t))],
[cos(theta1(t).diff(t)), sin(theta1(t).diff(t))]])
expected = (r'\left[\begin{matrix}\sin{\left '
r'(\theta_{1}{\left (t \right )} \right )} & '
r'\cos{\left (\theta_{1}{\left (t \right )} \right '
r')}\\\cos{\left (\frac{d}{d t} \theta_{1}{\left (t '
r'\right )} \right )} & \sin{\left (\frac{d}{d t} '
r'\theta_{1}{\left (t \right )} \right '
r')}\end{matrix}\right]')
assert latex(M) == expected
def test_latex_NDimArray():
x, y, z, w = symbols("x y z w")
for ArrayType in (ImmutableDenseNDimArray, ImmutableSparseNDimArray, MutableDenseNDimArray, MutableSparseNDimArray):
# Basic: scalar array
M = ArrayType(x)
assert latex(M) == "x"
M = ArrayType([[1 / x, y], [z, w]])
M1 = ArrayType([1 / x, y, z])
M2 = tensorproduct(M1, M)
M3 = tensorproduct(M, M)
assert latex(M) == '\\left[\\begin{matrix}\\frac{1}{x} & y\\\\z & w\\end{matrix}\\right]'
assert latex(M1) == "\\left[\\begin{matrix}\\frac{1}{x} & y & z\\end{matrix}\\right]"
assert latex(M2) == r"\left[\begin{matrix}" \
r"\left[\begin{matrix}\frac{1}{x^{2}} & \frac{y}{x}\\\frac{z}{x} & \frac{w}{x}\end{matrix}\right] & " \
r"\left[\begin{matrix}\frac{y}{x} & y^{2}\\y z & w y\end{matrix}\right] & " \
r"\left[\begin{matrix}\frac{z}{x} & y z\\z^{2} & w z\end{matrix}\right]" \
r"\end{matrix}\right]"
assert latex(M3) == r"""\left[\begin{matrix}"""\
r"""\left[\begin{matrix}\frac{1}{x^{2}} & \frac{y}{x}\\\frac{z}{x} & \frac{w}{x}\end{matrix}\right] & """\
r"""\left[\begin{matrix}\frac{y}{x} & y^{2}\\y z & w y\end{matrix}\right]\\"""\
r"""\left[\begin{matrix}\frac{z}{x} & y z\\z^{2} & w z\end{matrix}\right] & """\
r"""\left[\begin{matrix}\frac{w}{x} & w y\\w z & w^{2}\end{matrix}\right]"""\
r"""\end{matrix}\right]"""
Mrow = ArrayType([[x, y, 1/z]])
Mcolumn = ArrayType([[x], [y], [1/z]])
Mcol2 = ArrayType([Mcolumn.tolist()])
assert latex(Mrow) == r"\left[\left[\begin{matrix}x & y & \frac{1}{z}\end{matrix}\right]\right]"
assert latex(Mcolumn) == r"\left[\begin{matrix}x\\y\\\frac{1}{z}\end{matrix}\right]"
assert latex(Mcol2) == r'\left[\begin{matrix}\left[\begin{matrix}x\\y\\\frac{1}{z}\end{matrix}\right]\end{matrix}\right]'
def test_latex_mul_symbol():
assert latex(4*4**x, mul_symbol='times') == "4 \\times 4^{x}"
assert latex(4*4**x, mul_symbol='dot') == "4 \\cdot 4^{x}"
assert latex(4*4**x, mul_symbol='ldot') == r"4 \,.\, 4^{x}"
assert latex(4*x, mul_symbol='times') == "4 \\times x"
assert latex(4*x, mul_symbol='dot') == "4 \\cdot x"
assert latex(4*x, mul_symbol='ldot') == r"4 \,.\, x"
def test_latex_issue_4381():
y = 4*4**log(2)
assert latex(y) == r'4 \cdot 4^{\log{\left (2 \right )}}'
assert latex(1/y) == r'\frac{1}{4 \cdot 4^{\log{\left (2 \right )}}}'
def test_latex_issue_4576():
assert latex(Symbol("beta_13_2")) == r"\beta_{13 2}"
assert latex(Symbol("beta_132_20")) == r"\beta_{132 20}"
assert latex(Symbol("beta_13")) == r"\beta_{13}"
assert latex(Symbol("x_a_b")) == r"x_{a b}"
assert latex(Symbol("x_1_2_3")) == r"x_{1 2 3}"
assert latex(Symbol("x_a_b1")) == r"x_{a b1}"
assert latex(Symbol("x_a_1")) == r"x_{a 1}"
assert latex(Symbol("x_1_a")) == r"x_{1 a}"
assert latex(Symbol("x_1^aa")) == r"x^{aa}_{1}"
assert latex(Symbol("x_1__aa")) == r"x^{aa}_{1}"
assert latex(Symbol("x_11^a")) == r"x^{a}_{11}"
assert latex(Symbol("x_11__a")) == r"x^{a}_{11}"
assert latex(Symbol("x_a_a_a_a")) == r"x_{a a a a}"
assert latex(Symbol("x_a_a^a^a")) == r"x^{a a}_{a a}"
assert latex(Symbol("x_a_a__a__a")) == r"x^{a a}_{a a}"
assert latex(Symbol("alpha_11")) == r"\alpha_{11}"
assert latex(Symbol("alpha_11_11")) == r"\alpha_{11 11}"
assert latex(Symbol("alpha_alpha")) == r"\alpha_{\alpha}"
assert latex(Symbol("alpha^aleph")) == r"\alpha^{\aleph}"
assert latex(Symbol("alpha__aleph")) == r"\alpha^{\aleph}"
def test_latex_pow_fraction():
x = Symbol('x')
# Testing exp
assert 'e^{-x}' in latex(exp(-x)/2).replace(' ', '') # Remove Whitespace
# Testing just e^{-x} in case future changes alter behavior of muls or fracs
# In particular current output is \frac{1}{2}e^{- x} but perhaps this will
# change to \frac{e^{-x}}{2}
# Testing general, non-exp, power
assert '3^{-x}' in latex(3**-x/2).replace(' ', '')
def test_noncommutative():
A, B, C = symbols('A,B,C', commutative=False)
assert latex(A*B*C**-1) == "A B C^{-1}"
assert latex(C**-1*A*B) == "C^{-1} A B"
assert latex(A*C**-1*B) == "A C^{-1} B"
def test_latex_order():
expr = x**3 + x**2*y + 3*x*y**3 + y**4
assert latex(expr, order='lex') == "x^{3} + x^{2} y + 3 x y^{3} + y^{4}"
assert latex(
expr, order='rev-lex') == "y^{4} + 3 x y^{3} + x^{2} y + x^{3}"
def test_latex_Lambda():
assert latex(Lambda(x, x + 1)) == \
r"\left( x \mapsto x + 1 \right)"
assert latex(Lambda((x, y), x + 1)) == \
r"\left( \left ( x, \quad y\right ) \mapsto x + 1 \right)"
def test_latex_PolyElement():
Ruv, u,v = ring("u,v", ZZ)
Rxyz, x,y,z = ring("x,y,z", Ruv)
assert latex(x - x) == r"0"
assert latex(x - 1) == r"x - 1"
assert latex(x + 1) == r"x + 1"
assert latex((u**2 + 3*u*v + 1)*x**2*y + u + 1) == r"\left({u}^{2} + 3 u v + 1\right) {x}^{2} y + u + 1"
assert latex((u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x) == r"\left({u}^{2} + 3 u v + 1\right) {x}^{2} y + \left(u + 1\right) x"
assert latex((u**2 + 3*u*v + 1)*x**2*y + (u + 1)*x + 1) == r"\left({u}^{2} + 3 u v + 1\right) {x}^{2} y + \left(u + 1\right) x + 1"
assert latex((-u**2 + 3*u*v - 1)*x**2*y - (u + 1)*x - 1) == r"-\left({u}^{2} - 3 u v + 1\right) {x}^{2} y - \left(u + 1\right) x - 1"
assert latex(-(v**2 + v + 1)*x + 3*u*v + 1) == r"-\left({v}^{2} + v + 1\right) x + 3 u v + 1"
assert latex(-(v**2 + v + 1)*x - 3*u*v + 1) == r"-\left({v}^{2} + v + 1\right) x - 3 u v + 1"
def test_latex_FracElement():
Fuv, u,v = field("u,v", ZZ)
Fxyzt, x,y,z,t = field("x,y,z,t", Fuv)
assert latex(x - x) == r"0"
assert latex(x - 1) == r"x - 1"
assert latex(x + 1) == r"x + 1"
assert latex(x/3) == r"\frac{x}{3}"
assert latex(x/z) == r"\frac{x}{z}"
assert latex(x*y/z) == r"\frac{x y}{z}"
assert latex(x/(z*t)) == r"\frac{x}{z t}"
assert latex(x*y/(z*t)) == r"\frac{x y}{z t}"
assert latex((x - 1)/y) == r"\frac{x - 1}{y}"
assert latex((x + 1)/y) == r"\frac{x + 1}{y}"
assert latex((-x - 1)/y) == r"\frac{-x - 1}{y}"
assert latex((x + 1)/(y*z)) == r"\frac{x + 1}{y z}"
assert latex(-y/(x + 1)) == r"\frac{-y}{x + 1}"
assert latex(y*z/(x + 1)) == r"\frac{y z}{x + 1}"
assert latex(((u + 1)*x*y + 1)/((v - 1)*z - 1)) == r"\frac{\left(u + 1\right) x y + 1}{\left(v - 1\right) z - 1}"
assert latex(((u + 1)*x*y + 1)/((v - 1)*z - t*u*v - 1)) == r"\frac{\left(u + 1\right) x y + 1}{\left(v - 1\right) z - u v t - 1}"
def test_latex_Poly():
assert latex(Poly(x**2 + 2 * x, x)) == \
r"\operatorname{Poly}{\left( x^{2} + 2 x, x, domain=\mathbb{Z} \right)}"
assert latex(Poly(x/y, x)) == \
r"\operatorname{Poly}{\left( \frac{1}{y} x, x, domain=\mathbb{Z}\left(y\right) \right)}"
assert latex(Poly(2.0*x + y)) == \
r"\operatorname{Poly}{\left( 2.0 x + 1.0 y, x, y, domain=\mathbb{R} \right)}"
def test_latex_Poly_order():
assert latex(Poly([a, 1, b, 2, c, 3], x)) == \
'\\operatorname{Poly}{\\left( a x^{5} + x^{4} + b x^{3} + 2 x^{2} + c x + 3, x, domain=\\mathbb{Z}\\left[a, b, c\\right] \\right)}'
assert latex(Poly([a, 1, b+c, 2, 3], x)) == \
'\\operatorname{Poly}{\\left( a x^{4} + x^{3} + \\left(b + c\\right) x^{2} + 2 x + 3, x, domain=\\mathbb{Z}\\left[a, b, c\\right] \\right)}'
assert latex(Poly(a*x**3 + x**2*y - x*y - c*y**3 - b*x*y**2 + y - a*x + b, (x, y))) == \
'\\operatorname{Poly}{\\left( a x^{3} + x^{2}y - b xy^{2} - xy - a x - c y^{3} + y + b, x, y, domain=\\mathbb{Z}\\left[a, b, c\\right] \\right)}'
def test_latex_ComplexRootOf():
assert latex(rootof(x**5 + x + 3, 0)) == \
r"\operatorname{CRootOf} {\left(x^{5} + x + 3, 0\right)}"
def test_latex_RootSum():
assert latex(RootSum(x**5 + x + 3, sin)) == \
r"\operatorname{RootSum} {\left(x^{5} + x + 3, \left( x \mapsto \sin{\left (x \right )} \right)\right)}"
def test_settings():
raises(TypeError, lambda: latex(x*y, method="garbage"))
def test_latex_numbers():
assert latex(catalan(n)) == r"C_{n}"
assert latex(catalan(n)**2) == r"C_{n}^{2}"
def test_latex_euler():
assert latex(euler(n)) == r"E_{n}"
assert latex(euler(n, x)) == r"E_{n}\left(x\right)"
assert latex(euler(n, x)**2) == r"E_{n}^{2}\left(x\right)"
def test_lamda():
assert latex(Symbol('lamda')) == r"\lambda"
assert latex(Symbol('Lamda')) == r"\Lambda"
def test_custom_symbol_names():
x = Symbol('x')
y = Symbol('y')
assert latex(x) == "x"
assert latex(x, symbol_names={x: "x_i"}) == "x_i"
assert latex(x + y, symbol_names={x: "x_i"}) == "x_i + y"
assert latex(x**2, symbol_names={x: "x_i"}) == "x_i^{2}"
assert latex(x + y, symbol_names={x: "x_i", y: "y_j"}) == "x_i + y_j"
def test_matAdd():
from sympy import MatrixSymbol
from sympy.printing.latex import LatexPrinter
C = MatrixSymbol('C', 5, 5)
B = MatrixSymbol('B', 5, 5)
l = LatexPrinter()
assert l._print(C - 2*B) in ['- 2 B + C', 'C -2 B']
assert l._print(C + 2*B) in ['2 B + C', 'C + 2 B']
assert l._print(B - 2*C) in ['B - 2 C', '- 2 C + B']
assert l._print(B + 2*C) in ['B + 2 C', '2 C + B']
def test_matMul():
from sympy import MatrixSymbol
from sympy.printing.latex import LatexPrinter
A = MatrixSymbol('A', 5, 5)
B = MatrixSymbol('B', 5, 5)
x = Symbol('x')
l = LatexPrinter()
assert l._print_MatMul(2*A) == '2 A'
assert l._print_MatMul(2*x*A) == '2 x A'
assert l._print_MatMul(-2*A) == '- 2 A'
assert l._print_MatMul(1.5*A) == '1.5 A'
assert l._print_MatMul(sqrt(2)*A) == r'\sqrt{2} A'
assert l._print_MatMul(-sqrt(2)*A) == r'- \sqrt{2} A'
assert l._print_MatMul(2*sqrt(2)*x*A) == r'2 \sqrt{2} x A'
assert l._print_MatMul(-2*A*(A + 2*B)) in [r'- 2 A \left(A + 2 B\right)',
r'- 2 A \left(2 B + A\right)']
def test_latex_MatrixSlice():
from sympy.matrices.expressions import MatrixSymbol
assert latex(MatrixSymbol('X', 10, 10)[:5, 1:9:2]) == \
r'X\left[:5, 1:9:2\right]'
assert latex(MatrixSymbol('X', 10, 10)[5, :5:2]) == \
r'X\left[5, :5:2\right]'
def test_latex_RandomDomain():
from sympy.stats import Normal, Die, Exponential, pspace, where
X = Normal('x1', 0, 1)
assert latex(where(X > 0)) == r"Domain: 0 < x_{1} \wedge x_{1} < \infty"
D = Die('d1', 6)
assert latex(where(D > 4)) == r"Domain: d_{1} = 5 \vee d_{1} = 6"
A = Exponential('a', 1)
B = Exponential('b', 1)
assert latex(
pspace(Tuple(A, B)).domain) == \
r"Domain: 0 \leq a \wedge 0 \leq b \wedge a < \infty \wedge b < \infty"
def test_PrettyPoly():
from sympy.polys.domains import QQ
F = QQ.frac_field(x, y)
R = QQ[x, y]
assert latex(F.convert(x/(x + y))) == latex(x/(x + y))
assert latex(R.convert(x + y)) == latex(x + y)
def test_integral_transforms():
x = Symbol("x")
k = Symbol("k")
f = Function("f")
a = Symbol("a")
b = Symbol("b")
assert latex(MellinTransform(f(x), x, k)) == r"\mathcal{M}_{x}\left[f{\left (x \right )}\right]\left(k\right)"
assert latex(InverseMellinTransform(f(k), k, x, a, b)) == r"\mathcal{M}^{-1}_{k}\left[f{\left (k \right )}\right]\left(x\right)"
assert latex(LaplaceTransform(f(x), x, k)) == r"\mathcal{L}_{x}\left[f{\left (x \right )}\right]\left(k\right)"
assert latex(InverseLaplaceTransform(f(k), k, x, (a, b))) == r"\mathcal{L}^{-1}_{k}\left[f{\left (k \right )}\right]\left(x\right)"
assert latex(FourierTransform(f(x), x, k)) == r"\mathcal{F}_{x}\left[f{\left (x \right )}\right]\left(k\right)"
assert latex(InverseFourierTransform(f(k), k, x)) == r"\mathcal{F}^{-1}_{k}\left[f{\left (k \right )}\right]\left(x\right)"
assert latex(CosineTransform(f(x), x, k)) == r"\mathcal{COS}_{x}\left[f{\left (x \right )}\right]\left(k\right)"
assert latex(InverseCosineTransform(f(k), k, x)) == r"\mathcal{COS}^{-1}_{k}\left[f{\left (k \right )}\right]\left(x\right)"
assert latex(SineTransform(f(x), x, k)) == r"\mathcal{SIN}_{x}\left[f{\left (x \right )}\right]\left(k\right)"
assert latex(InverseSineTransform(f(k), k, x)) == r"\mathcal{SIN}^{-1}_{k}\left[f{\left (k \right )}\right]\left(x\right)"
def test_PolynomialRingBase():
from sympy.polys.domains import QQ
assert latex(QQ.old_poly_ring(x, y)) == r"\mathbb{Q}\left[x, y\right]"
assert latex(QQ.old_poly_ring(x, y, order="ilex")) == \
r"S_<^{-1}\mathbb{Q}\left[x, y\right]"
def test_categories():
from sympy.categories import (Object, IdentityMorphism,
NamedMorphism, Category, Diagram, DiagramGrid)
A1 = Object("A1")
A2 = Object("A2")
A3 = Object("A3")
f1 = NamedMorphism(A1, A2, "f1")
f2 = NamedMorphism(A2, A3, "f2")
id_A1 = IdentityMorphism(A1)
K1 = Category("K1")
assert latex(A1) == "A_{1}"
assert latex(f1) == "f_{1}:A_{1}\\rightarrow A_{2}"
assert latex(id_A1) == "id:A_{1}\\rightarrow A_{1}"
assert latex(f2*f1) == "f_{2}\\circ f_{1}:A_{1}\\rightarrow A_{3}"
assert latex(K1) == r"\mathbf{K_{1}}"
d = Diagram()
assert latex(d) == r"\emptyset"
d = Diagram({f1: "unique", f2: S.EmptySet})
assert latex(d) == r"\left \{ f_{2}\circ f_{1}:A_{1}" \
r"\rightarrow A_{3} : \emptyset, \quad id:A_{1}\rightarrow " \
r"A_{1} : \emptyset, \quad id:A_{2}\rightarrow A_{2} : " \
r"\emptyset, \quad id:A_{3}\rightarrow A_{3} : \emptyset, " \
r"\quad f_{1}:A_{1}\rightarrow A_{2} : \left\{unique\right\}, " \
r"\quad f_{2}:A_{2}\rightarrow A_{3} : \emptyset\right \}"
d = Diagram({f1: "unique", f2: S.EmptySet}, {f2 * f1: "unique"})
assert latex(d) == r"\left \{ f_{2}\circ f_{1}:A_{1}" \
r"\rightarrow A_{3} : \emptyset, \quad id:A_{1}\rightarrow " \
r"A_{1} : \emptyset, \quad id:A_{2}\rightarrow A_{2} : " \
r"\emptyset, \quad id:A_{3}\rightarrow A_{3} : \emptyset, " \
r"\quad f_{1}:A_{1}\rightarrow A_{2} : \left\{unique\right\}," \
r" \quad f_{2}:A_{2}\rightarrow A_{3} : \emptyset\right \}" \
r"\Longrightarrow \left \{ f_{2}\circ f_{1}:A_{1}" \
r"\rightarrow A_{3} : \left\{unique\right\}\right \}"
# A linear diagram.
A = Object("A")
B = Object("B")
C = Object("C")
f = NamedMorphism(A, B, "f")
g = NamedMorphism(B, C, "g")
d = Diagram([f, g])
grid = DiagramGrid(d)
assert latex(grid) == "\\begin{array}{cc}\n" \
"A & B \\\\\n" \
" & C \n" \
"\\end{array}\n"
def test_Modules():
from sympy.polys.domains import QQ
from sympy.polys.agca import homomorphism
R = QQ.old_poly_ring(x, y)
F = R.free_module(2)
M = F.submodule([x, y], [1, x**2])
assert latex(F) == r"{\mathbb{Q}\left[x, y\right]}^{2}"
assert latex(M) == \
r"\left< {\left[ {x},{y} \right]},{\left[ {1},{x^{2}} \right]} \right>"
I = R.ideal(x**2, y)
assert latex(I) == r"\left< {x^{2}},{y} \right>"
Q = F / M
assert latex(Q) == r"\frac{{\mathbb{Q}\left[x, y\right]}^{2}}{\left< {\left[ {x},{y} \right]},{\left[ {1},{x^{2}} \right]} \right>}"
assert latex(Q.submodule([1, x**3/2], [2, y])) == \
r"\left< {{\left[ {1},{\frac{x^{3}}{2}} \right]} + {\left< {\left[ {x},{y} \right]},{\left[ {1},{x^{2}} \right]} \right>}},{{\left[ {2},{y} \right]} + {\left< {\left[ {x},{y} \right]},{\left[ {1},{x^{2}} \right]} \right>}} \right>"
h = homomorphism(QQ.old_poly_ring(x).free_module(2), QQ.old_poly_ring(x).free_module(2), [0, 0])
assert latex(h) == r"{\left[\begin{matrix}0 & 0\\0 & 0\end{matrix}\right]} : {{\mathbb{Q}\left[x\right]}^{2}} \to {{\mathbb{Q}\left[x\right]}^{2}}"
def test_QuotientRing():
from sympy.polys.domains import QQ
R = QQ.old_poly_ring(x)/[x**2 + 1]
assert latex(
R) == r"\frac{\mathbb{Q}\left[x\right]}{\left< {x^{2} + 1} \right>}"
assert latex(R.one) == r"{1} + {\left< {x^{2} + 1} \right>}"
def test_Tr():
#TODO: Handle indices
A, B = symbols('A B', commutative=False)
t = Tr(A*B)
assert latex(t) == r'\mbox{Tr}\left(A B\right)'
def test_Adjoint():
from sympy.matrices import MatrixSymbol, Adjoint, Inverse, Transpose
X = MatrixSymbol('X', 2, 2)
Y = MatrixSymbol('Y', 2, 2)
assert latex(Adjoint(X)) == r'X^\dagger'
assert latex(Adjoint(X + Y)) == r'\left(X + Y\right)^\dagger'
assert latex(Adjoint(X) + Adjoint(Y)) == r'X^\dagger + Y^\dagger'
assert latex(Adjoint(X*Y)) == r'\left(X Y\right)^\dagger'
assert latex(Adjoint(Y)*Adjoint(X)) == r'Y^\dagger X^\dagger'
assert latex(Adjoint(X**2)) == r'\left(X^{2}\right)^\dagger'
assert latex(Adjoint(X)**2) == r'\left(X^\dagger\right)^{2}'
assert latex(Adjoint(Inverse(X))) == r'\left(X^{-1}\right)^\dagger'
assert latex(Inverse(Adjoint(X))) == r'\left(X^\dagger\right)^{-1}'
assert latex(Adjoint(Transpose(X))) == r'\left(X^T\right)^\dagger'
assert latex(Transpose(Adjoint(X))) == r'\left(X^\dagger\right)^T'
def test_Hadamard():
from sympy.matrices import MatrixSymbol, HadamardProduct
X = MatrixSymbol('X', 2, 2)
Y = MatrixSymbol('Y', 2, 2)
assert latex(HadamardProduct(X, Y*Y)) == r'X \circ Y^{2}'
assert latex(HadamardProduct(X, Y)*Y) == r'\left(X \circ Y\right) Y'
def test_ZeroMatrix():
from sympy import ZeroMatrix
assert latex(ZeroMatrix(1, 1)) == r"\mathbb{0}"
def test_boolean_args_order():
syms = symbols('a:f')
expr = And(*syms)
assert latex(expr) == 'a \\wedge b \\wedge c \\wedge d \\wedge e \\wedge f'
expr = Or(*syms)
assert latex(expr) == 'a \\vee b \\vee c \\vee d \\vee e \\vee f'
expr = Equivalent(*syms)
assert latex(expr) == 'a \\Leftrightarrow b \\Leftrightarrow c \\Leftrightarrow d \\Leftrightarrow e \\Leftrightarrow f'
expr = Xor(*syms)
assert latex(expr) == 'a \\veebar b \\veebar c \\veebar d \\veebar e \\veebar f'
def test_imaginary():
i = sqrt(-1)
assert latex(i) == r'i'
def test_builtins_without_args():
assert latex(sin) == r'\sin'
assert latex(cos) == r'\cos'
assert latex(tan) == r'\tan'
assert latex(log) == r'\log'
assert latex(Ei) == r'\operatorname{Ei}'
assert latex(zeta) == r'\zeta'
def test_latex_greek_functions():
# bug because capital greeks that have roman equivalents should not use
# \Alpha, \Beta, \Eta, etc.
s = Function('Alpha')
assert latex(s) == r'A'
assert latex(s(x)) == r'A{\left (x \right )}'
s = Function('Beta')
assert latex(s) == r'B'
s = Function('Eta')
assert latex(s) == r'H'
assert latex(s(x)) == r'H{\left (x \right )}'
# bug because sympy.core.numbers.Pi is special
p = Function('Pi')
# assert latex(p(x)) == r'\Pi{\left (x \right )}'
assert latex(p) == r'\Pi'
# bug because not all greeks are included
c = Function('chi')
assert latex(c(x)) == r'\chi{\left (x \right )}'
assert latex(c) == r'\chi'
def test_translate():
s = 'Alpha'
assert translate(s) == 'A'
s = 'Beta'
assert translate(s) == 'B'
s = 'Eta'
assert translate(s) == 'H'
s = 'omicron'
assert translate(s) == 'o'
s = 'Pi'
assert translate(s) == r'\Pi'
s = 'pi'
assert translate(s) == r'\pi'
s = 'LamdaHatDOT'
assert translate(s) == r'\dot{\hat{\Lambda}}'
def test_other_symbols():
from sympy.printing.latex import other_symbols
for s in other_symbols:
assert latex(symbols(s)) == "\\"+s
def test_modifiers():
# Test each modifier individually in the simplest case (with funny capitalizations)
assert latex(symbols("xMathring")) == r"\mathring{x}"
assert latex(symbols("xCheck")) == r"\check{x}"
assert latex(symbols("xBreve")) == r"\breve{x}"
assert latex(symbols("xAcute")) == r"\acute{x}"
assert latex(symbols("xGrave")) == r"\grave{x}"
assert latex(symbols("xTilde")) == r"\tilde{x}"
assert latex(symbols("xPrime")) == r"{x}'"
assert latex(symbols("xddDDot")) == r"\ddddot{x}"
assert latex(symbols("xDdDot")) == r"\dddot{x}"
assert latex(symbols("xDDot")) == r"\ddot{x}"
assert latex(symbols("xBold")) == r"\boldsymbol{x}"
assert latex(symbols("xnOrM")) == r"\left\|{x}\right\|"
assert latex(symbols("xAVG")) == r"\left\langle{x}\right\rangle"
assert latex(symbols("xHat")) == r"\hat{x}"
assert latex(symbols("xDot")) == r"\dot{x}"
assert latex(symbols("xBar")) == r"\bar{x}"
assert latex(symbols("xVec")) == r"\vec{x}"
assert latex(symbols("xAbs")) == r"\left|{x}\right|"
assert latex(symbols("xMag")) == r"\left|{x}\right|"
assert latex(symbols("xPrM")) == r"{x}'"
assert latex(symbols("xBM")) == r"\boldsymbol{x}"
# Test strings that are *only* the names of modifiers
assert latex(symbols("Mathring")) == r"Mathring"
assert latex(symbols("Check")) == r"Check"
assert latex(symbols("Breve")) == r"Breve"
assert latex(symbols("Acute")) == r"Acute"
assert latex(symbols("Grave")) == r"Grave"
assert latex(symbols("Tilde")) == r"Tilde"
assert latex(symbols("Prime")) == r"Prime"
assert latex(symbols("DDot")) == r"\dot{D}"
assert latex(symbols("Bold")) == r"Bold"
assert latex(symbols("NORm")) == r"NORm"
assert latex(symbols("AVG")) == r"AVG"
assert latex(symbols("Hat")) == r"Hat"
assert latex(symbols("Dot")) == r"Dot"
assert latex(symbols("Bar")) == r"Bar"
assert latex(symbols("Vec")) == r"Vec"
assert latex(symbols("Abs")) == r"Abs"
assert latex(symbols("Mag")) == r"Mag"
assert latex(symbols("PrM")) == r"PrM"
assert latex(symbols("BM")) == r"BM"
assert latex(symbols("hbar")) == r"\hbar"
# Check a few combinations
assert latex(symbols("xvecdot")) == r"\dot{\vec{x}}"
assert latex(symbols("xDotVec")) == r"\vec{\dot{x}}"
assert latex(symbols("xHATNorm")) == r"\left\|{\hat{x}}\right\|"
# Check a couple big, ugly combinations
assert latex(symbols('xMathringBm_yCheckPRM__zbreveAbs')) == r"\boldsymbol{\mathring{x}}^{\left|{\breve{z}}\right|}_{{\check{y}}'}"
assert latex(symbols('alphadothat_nVECDOT__tTildePrime')) == r"\hat{\dot{\alpha}}^{{\tilde{t}}'}_{\dot{\vec{n}}}"
def test_greek_symbols():
assert latex(Symbol('alpha')) == r'\alpha'
assert latex(Symbol('beta')) == r'\beta'
assert latex(Symbol('gamma')) == r'\gamma'
assert latex(Symbol('delta')) == r'\delta'
assert latex(Symbol('epsilon')) == r'\epsilon'
assert latex(Symbol('zeta')) == r'\zeta'
assert latex(Symbol('eta')) == r'\eta'
assert latex(Symbol('theta')) == r'\theta'
assert latex(Symbol('iota')) == r'\iota'
assert latex(Symbol('kappa')) == r'\kappa'
assert latex(Symbol('lambda')) == r'\lambda'
assert latex(Symbol('mu')) == r'\mu'
assert latex(Symbol('nu')) == r'\nu'
assert latex(Symbol('xi')) == r'\xi'
assert latex(Symbol('omicron')) == r'o'
assert latex(Symbol('pi')) == r'\pi'
assert latex(Symbol('rho')) == r'\rho'
assert latex(Symbol('sigma')) == r'\sigma'
assert latex(Symbol('tau')) == r'\tau'
assert latex(Symbol('upsilon')) == r'\upsilon'
assert latex(Symbol('phi')) == r'\phi'
assert latex(Symbol('chi')) == r'\chi'
assert latex(Symbol('psi')) == r'\psi'
assert latex(Symbol('omega')) == r'\omega'
assert latex(Symbol('Alpha')) == r'A'
assert latex(Symbol('Beta')) == r'B'
assert latex(Symbol('Gamma')) == r'\Gamma'
assert latex(Symbol('Delta')) == r'\Delta'
assert latex(Symbol('Epsilon')) == r'E'
assert latex(Symbol('Zeta')) == r'Z'
assert latex(Symbol('Eta')) == r'H'
assert latex(Symbol('Theta')) == r'\Theta'
assert latex(Symbol('Iota')) == r'I'
assert latex(Symbol('Kappa')) == r'K'
assert latex(Symbol('Lambda')) == r'\Lambda'
assert latex(Symbol('Mu')) == r'M'
assert latex(Symbol('Nu')) == r'N'
assert latex(Symbol('Xi')) == r'\Xi'
assert latex(Symbol('Omicron')) == r'O'
assert latex(Symbol('Pi')) == r'\Pi'
assert latex(Symbol('Rho')) == r'P'
assert latex(Symbol('Sigma')) == r'\Sigma'
assert latex(Symbol('Tau')) == r'T'
assert latex(Symbol('Upsilon')) == r'\Upsilon'
assert latex(Symbol('Phi')) == r'\Phi'
assert latex(Symbol('Chi')) == r'X'
assert latex(Symbol('Psi')) == r'\Psi'
assert latex(Symbol('Omega')) == r'\Omega'
assert latex(Symbol('varepsilon')) == r'\varepsilon'
assert latex(Symbol('varkappa')) == r'\varkappa'
assert latex(Symbol('varphi')) == r'\varphi'
assert latex(Symbol('varpi')) == r'\varpi'
assert latex(Symbol('varrho')) == r'\varrho'
assert latex(Symbol('varsigma')) == r'\varsigma'
assert latex(Symbol('vartheta')) == r'\vartheta'
@XFAIL
def test_builtin_without_args_mismatched_names():
assert latex(CosineTransform) == r'\mathcal{COS}'
def test_builtin_no_args():
assert latex(Chi) == r'\operatorname{Chi}'
assert latex(beta) == r'\operatorname{B}'
assert latex(gamma) == r'\Gamma'
assert latex(KroneckerDelta) == r'\delta'
assert latex(DiracDelta) == r'\delta'
assert latex(lowergamma) == r'\gamma'
def test_issue_6853():
p = Function('Pi')
assert latex(p(x)) == r"\Pi{\left (x \right )}"
def test_Mul():
e = Mul(-2, x + 1, evaluate=False)
assert latex(e) == r'- 2 \left(x + 1\right)'
e = Mul(2, x + 1, evaluate=False)
assert latex(e) == r'2 \left(x + 1\right)'
e = Mul(S.One/2, x + 1, evaluate=False)
assert latex(e) == r'\frac{x + 1}{2}'
e = Mul(y, x + 1, evaluate=False)
assert latex(e) == r'y \left(x + 1\right)'
e = Mul(-y, x + 1, evaluate=False)
assert latex(e) == r'- y \left(x + 1\right)'
e = Mul(-2, x + 1)
assert latex(e) == r'- 2 x - 2'
e = Mul(2, x + 1)
assert latex(e) == r'2 x + 2'
def test_Pow():
e = Pow(2, 2, evaluate=False)
assert latex(e) == r'2^{2}'
def test_issue_7180():
assert latex(Equivalent(x, y)) == r"x \Leftrightarrow y"
assert latex(Not(Equivalent(x, y))) == r"x \not\Leftrightarrow y"
def test_issue_8409():
assert latex(S.Half**n) == r"\left(\frac{1}{2}\right)^{n}"
def test_issue_8470():
from sympy.parsing.sympy_parser import parse_expr
e = parse_expr("-B*A", evaluate=False)
assert latex(e) == r"A \left(- B\right)"
def test_issue_7117():
# See also issue #5031 (hence the evaluate=False in these).
e = Eq(x + 1, 2*x)
q = Mul(2, e, evaluate=False)
assert latex(q) == r"2 \left(x + 1 = 2 x\right)"
q = Add(6, e, evaluate=False)
assert latex(q) == r"6 + \left(x + 1 = 2 x\right)"
q = Pow(e, 2, evaluate=False)
assert latex(q) == r"\left(x + 1 = 2 x\right)^{2}"
def test_issue_15439():
x = MatrixSymbol('x', 2, 2)
y = MatrixSymbol('y', 2, 2)
assert latex((x * y).subs(y, -y)) == r"x \left(- y\right)"
assert latex((x * y).subs(y, -2*y)) == r"x \left(- 2 y\right)"
assert latex((x * y).subs(x, -x)) == r"- x y"
def test_issue_2934():
assert latex(Symbol(r'\frac{a_1}{b_1}')) == '\\frac{a_1}{b_1}'
def test_issue_10489():
latexSymbolWithBrace = 'C_{x_{0}}'
s = Symbol(latexSymbolWithBrace)
assert latex(s) == latexSymbolWithBrace
assert latex(cos(s)) == r'\cos{\left (C_{x_{0}} \right )}'
def test_issue_12886():
m__1, l__1 = symbols('m__1, l__1')
assert latex(m__1**2 + l__1**2) == r'\left(l^{1}\right)^{2} + \left(m^{1}\right)^{2}'
def test_issue_13559():
from sympy.parsing.sympy_parser import parse_expr
expr = parse_expr('5/1', evaluate=False)
assert latex(expr) == r"\frac{5}{1}"
def test_issue_13651():
expr = c + Mul(-1, a + b, evaluate=False)
assert latex(expr) == r"c - \left(a + b\right)"
def test_latex_UnevaluatedExpr():
x = symbols("x")
he = UnevaluatedExpr(1/x)
assert latex(he) == latex(1/x) == r"\frac{1}{x}"
assert latex(he**2) == r"\left(\frac{1}{x}\right)^{2}"
assert latex(he + 1) == r"1 + \frac{1}{x}"
assert latex(x*he) == r"x \frac{1}{x}"
def test_MatrixElement_printing():
# test cases for issue #11821
A = MatrixSymbol("A", 1, 3)
B = MatrixSymbol("B", 1, 3)
C = MatrixSymbol("C", 1, 3)
assert latex(A[0, 0]) == r"A_{0, 0}"
assert latex(3 * A[0, 0]) == r"3 A_{0, 0}"
F = C[0, 0].subs(C, A - B)
assert latex(F) == r"\left(A - B\right)_{0, 0}"
i, j, k = symbols("i j k")
M = MatrixSymbol("M", k, k)
N = MatrixSymbol("N", k, k)
assert latex((M*N)[i, j]) == r'\sum_{i_{1}=0}^{k - 1} M_{i, i_{1}} N_{i_{1}, j}'
def test_MatrixSymbol_printing():
# test cases for issue #14237
A = MatrixSymbol("A", 3, 3)
B = MatrixSymbol("B", 3, 3)
C = MatrixSymbol("C", 3, 3)
assert latex(-A) == r"- A"
assert latex(A - A*B - B) == r"A - A B - B"
assert latex(-A*B - A*B*C - B) == r"- A B - A B C - B"
def test_Quaternion_latex_printing():
q = Quaternion(x, y, z, t)
assert latex(q) == "x + y i + z j + t k"
q = Quaternion(x,y,z,x*t)
assert latex(q) == "x + y i + z j + t x k"
q = Quaternion(x,y,z,x+t)
assert latex(q) == r"x + y i + z j + \left(t + x\right) k"
def test_TensorProduct_printing():
from sympy.tensor.functions import TensorProduct
A = MatrixSymbol("A", 3, 3)
B = MatrixSymbol("B", 3, 3)
assert latex(TensorProduct(A, B)) == r"A \otimes B"
def test_WedgeProduct_printing():
from sympy.diffgeom.rn import R2
from sympy.diffgeom import WedgeProduct
wp = WedgeProduct(R2.dx, R2.dy)
assert latex(wp) == r"\mathrm{d}x \wedge \mathrm{d}y"
def test_issue_14041():
import sympy.physics.mechanics as me
A_frame = me.ReferenceFrame('A')
thetad, phid = me.dynamicsymbols('theta, phi', 1)
L = Symbol('L')
assert latex(L*(phid + thetad)**2*A_frame.x) == \
r"L \left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}"
assert latex((phid + thetad)**2*A_frame.x) == \
r"\left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}"
assert latex((phid*thetad)**a*A_frame.x) == \
r"\left(\dot{\phi} \dot{\theta}\right)^{a}\mathbf{\hat{a}_x}"
def test_issue_9216():
expr_1 = Pow(1, -1, evaluate=False)
assert latex(expr_1) == r"1^{-1}"
expr_2 = Pow(1, Pow(1, -1, evaluate=False), evaluate=False)
assert latex(expr_2) == r"1^{1^{-1}}"
expr_3 = Pow(3, -2, evaluate=False)
assert latex(expr_3) == r"\frac{1}{9}"
expr_4 = Pow(1, -2, evaluate=False)
assert latex(expr_4) == r"1^{-2}"
def test_latex_printer_tensor():
from sympy.tensor.tensor import TensorIndexType, tensor_indices, tensorhead
L = TensorIndexType("L")
i, j, k, l = tensor_indices("i j k l", L)
i0 = tensor_indices("i_0", L)
A, B, C, D = tensorhead("A B C D", [L], [[1]])
H = tensorhead("H", [L, L], [[1], [1]])
K = tensorhead("K", [L, L, L, L], [[1], [1], [1], [1]])
assert latex(i) == "{}^{i}"
assert latex(-i) == "{}_{i}"
expr = A(i)
assert latex(expr) == "A{}^{i}"
expr = A(i0)
assert latex(expr) == "A{}^{i_{0}}"
expr = A(-i)
assert latex(expr) == "A{}_{i}"
expr = -3*A(i)
assert latex(expr) == r"-3A{}^{i}"
expr = K(i, j, -k, -i0)
assert latex(expr) == "K{}^{ij}{}_{ki_{0}}"
expr = K(i, -j, -k, i0)
assert latex(expr) == "K{}^{i}{}_{jk}{}^{i_{0}}"
expr = K(i, -j, k, -i0)
assert latex(expr) == "K{}^{i}{}_{j}{}^{k}{}_{i_{0}}"
expr = H(i, -j)
assert latex(expr) == "H{}^{i}{}_{j}"
expr = H(i, j)
assert latex(expr) == "H{}^{ij}"
expr = H(-i, -j)
assert latex(expr) == "H{}_{ij}"
expr = (1+x)*A(i)
assert latex(expr) == r"\left(x + 1\right)A{}^{i}"
expr = H(i, -i)
assert latex(expr) == "H{}^{L_{0}}{}_{L_{0}}"
expr = H(i, -j)*A(j)*B(k)
assert latex(expr) == "H{}^{i}{}_{L_{0}}A{}^{L_{0}}B{}^{k}"
expr = A(i) + 3*B(i)
assert latex(expr) == "3B{}^{i} + A{}^{i}"
## Test ``TensorElement``:
from sympy.tensor.tensor import TensorElement
expr = TensorElement(K(i,j,k,l), {i:3, k:2})
assert latex(expr) == 'K{}^{i=3,j,k=2,l}'
expr = TensorElement(K(i,j,k,l), {i:3})
assert latex(expr) == 'K{}^{i=3,jkl}'
expr = TensorElement(K(i,-j,k,l), {i:3, k:2})
assert latex(expr) == 'K{}^{i=3}{}_{j}{}^{k=2,l}'
expr = TensorElement(K(i,-j,k,-l), {i:3, k:2})
assert latex(expr) == 'K{}^{i=3}{}_{j}{}^{k=2}{}_{l}'
expr = TensorElement(K(i,j,-k,-l), {i:3, -k:2})
assert latex(expr) == 'K{}^{i=3,j}{}_{k=2,l}'
expr = TensorElement(K(i,j,-k,-l), {i:3})
assert latex(expr) == 'K{}^{i=3,j}{}_{kl}'
def test_trace():
# Issue 15303
from sympy import trace
A = MatrixSymbol("A", 2, 2)
assert latex(trace(A)) == r"\mathrm{tr}\left (A \right )"
assert latex(trace(A**2)) == r"\mathrm{tr}\left (A^{2} \right )"
def test_print_basic():
# Issue 15303
from sympy import Basic, Expr
# dummy class for testing printing where the function is not implemented in latex.py
class UnimplementedExpr(Expr):
def __new__(cls, e):
return Basic.__new__(cls, e)
# dummy function for testing
def unimplemented_expr(expr):
return UnimplementedExpr(expr).doit()
# override class name to use superscript / subscript
def unimplemented_expr_sup_sub(expr):
result = UnimplementedExpr(expr)
result.__class__.__name__ = 'UnimplementedExpr_x^1'
return result
assert latex(unimplemented_expr(x)) == r'UnimplementedExpr\left(x\right)'
assert latex(unimplemented_expr(x**2)) == r'UnimplementedExpr\left(x^{2}\right)'
assert latex(unimplemented_expr_sup_sub(x)) == r'UnimplementedExpr^{1}_{x}\left(x\right)'
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878b1af3a5b211e74b23eb82b2248d48b6b774c38f78ff826fd6e500c669ef8b
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# -*- coding: utf-8 -*-
from sympy import (
Add, And, Basic, Derivative, Dict, Eq, Equivalent, FF,
FiniteSet, Function, Ge, Gt, I, Implies, Integral, SingularityFunction,
Lambda, Le, Limit, Lt, Matrix, Mul, Nand, Ne, Nor, Not, O, Or,
Pow, Product, QQ, RR, Rational, Ray, rootof, RootSum, S,
Segment, Subs, Sum, Symbol, Tuple, Trace, Xor, ZZ, conjugate,
groebner, oo, pi, symbols, ilex, grlex, Range, Contains,
SeqPer, SeqFormula, SeqAdd, SeqMul, fourier_series, fps, ITE,
Complement, Interval, Intersection, Union, EulerGamma, GoldenRatio)
from sympy.core.expr import UnevaluatedExpr
from sympy.physics import mechanics
from sympy.functions import (Abs, Chi, Ci, Ei, KroneckerDelta,
Piecewise, Shi, Si, atan2, beta, binomial, catalan, ceiling, cos,
euler, exp, expint, factorial, factorial2, floor, gamma, hyper, log,
meijerg, sin, sqrt, subfactorial, tan, uppergamma,
elliptic_k, elliptic_f, elliptic_e, elliptic_pi, DiracDelta)
from sympy.codegen.ast import (Assignment, AddAugmentedAssignment,
SubAugmentedAssignment, MulAugmentedAssignment, DivAugmentedAssignment, ModAugmentedAssignment)
from sympy.matrices import Adjoint, Inverse, MatrixSymbol, Transpose, KroneckerProduct
from sympy.printing.pretty import pretty as xpretty
from sympy.printing.pretty import pprint
from sympy.physics.units import joule, degree, radian
from sympy.tensor.array import (ImmutableDenseNDimArray, ImmutableSparseNDimArray,
MutableDenseNDimArray, MutableSparseNDimArray, tensorproduct)
from sympy.utilities.pytest import raises, XFAIL
from sympy.core.trace import Tr
from sympy.core.compatibility import u_decode as u
from sympy.core.compatibility import range
from sympy.vector import CoordSys3D, Gradient, Curl, Divergence, Dot, Cross
from sympy.tensor.functions import TensorProduct
from sympy.sets.setexpr import SetExpr
from sympy.sets import ImageSet
from sympy.tensor.tensor import (TensorIndexType, tensor_indices, tensorhead,
TensorElement)
import sympy as sym
class lowergamma(sym.lowergamma):
pass # testing notation inheritance by a subclass with same name
a, b, c, d, x, y, z, k, n = symbols('a,b,c,d,x,y,z,k,n')
f = Function("f")
th = Symbol('theta')
ph = Symbol('phi')
"""
Expressions whose pretty-printing is tested here:
(A '#' to the right of an expression indicates that its various acceptable
orderings are accounted for by the tests.)
BASIC EXPRESSIONS:
oo
(x**2)
1/x
y*x**-2
x**Rational(-5,2)
(-2)**x
Pow(3, 1, evaluate=False)
(x**2 + x + 1) #
1-x #
1-2*x #
x/y
-x/y
(x+2)/y #
(1+x)*y #3
-5*x/(x+10) # correct placement of negative sign
1 - Rational(3,2)*(x+1)
-(-x + 5)*(-x - 2*sqrt(2) + 5) - (-y + 5)*(-y + 5) # issue 5524
ORDERING:
x**2 + x + 1
1 - x
1 - 2*x
2*x**4 + y**2 - x**2 + y**3
RELATIONAL:
Eq(x, y)
Lt(x, y)
Gt(x, y)
Le(x, y)
Ge(x, y)
Ne(x/(y+1), y**2) #
RATIONAL NUMBERS:
y*x**-2
y**Rational(3,2) * x**Rational(-5,2)
sin(x)**3/tan(x)**2
FUNCTIONS (ABS, CONJ, EXP, FUNCTION BRACES, FACTORIAL, FLOOR, CEILING):
(2*x + exp(x)) #
Abs(x)
Abs(x/(x**2+1)) #
Abs(1 / (y - Abs(x)))
factorial(n)
factorial(2*n)
subfactorial(n)
subfactorial(2*n)
factorial(factorial(factorial(n)))
factorial(n+1) #
conjugate(x)
conjugate(f(x+1)) #
f(x)
f(x, y)
f(x/(y+1), y) #
f(x**x**x**x**x**x)
sin(x)**2
conjugate(a+b*I)
conjugate(exp(a+b*I))
conjugate( f(1 + conjugate(f(x))) ) #
f(x/(y+1), y) # denom of first arg
floor(1 / (y - floor(x)))
ceiling(1 / (y - ceiling(x)))
SQRT:
sqrt(2)
2**Rational(1,3)
2**Rational(1,1000)
sqrt(x**2 + 1)
(1 + sqrt(5))**Rational(1,3)
2**(1/x)
sqrt(2+pi)
(2+(1+x**2)/(2+x))**Rational(1,4)+(1+x**Rational(1,1000))/sqrt(3+x**2)
DERIVATIVES:
Derivative(log(x), x, evaluate=False)
Derivative(log(x), x, evaluate=False) + x #
Derivative(log(x) + x**2, x, y, evaluate=False)
Derivative(2*x*y, y, x, evaluate=False) + x**2 #
beta(alpha).diff(alpha)
INTEGRALS:
Integral(log(x), x)
Integral(x**2, x)
Integral((sin(x))**2 / (tan(x))**2)
Integral(x**(2**x), x)
Integral(x**2, (x,1,2))
Integral(x**2, (x,Rational(1,2),10))
Integral(x**2*y**2, x,y)
Integral(x**2, (x, None, 1))
Integral(x**2, (x, 1, None))
Integral(sin(th)/cos(ph), (th,0,pi), (ph, 0, 2*pi))
MATRICES:
Matrix([[x**2+1, 1], [y, x+y]]) #
Matrix([[x/y, y, th], [0, exp(I*k*ph), 1]])
PIECEWISE:
Piecewise((x,x<1),(x**2,True))
ITE:
ITE(x, y, z)
SEQUENCES (TUPLES, LISTS, DICTIONARIES):
()
[]
{}
(1/x,)
[x**2, 1/x, x, y, sin(th)**2/cos(ph)**2]
(x**2, 1/x, x, y, sin(th)**2/cos(ph)**2)
{x: sin(x)}
{1/x: 1/y, x: sin(x)**2} #
[x**2]
(x**2,)
{x**2: 1}
LIMITS:
Limit(x, x, oo)
Limit(x**2, x, 0)
Limit(1/x, x, 0)
Limit(sin(x)/x, x, 0)
UNITS:
joule => kg*m**2/s
SUBS:
Subs(f(x), x, ph**2)
Subs(f(x).diff(x), x, 0)
Subs(f(x).diff(x)/y, (x, y), (0, Rational(1, 2)))
ORDER:
O(1)
O(1/x)
O(x**2 + y**2)
"""
def pretty(expr, order=None):
"""ASCII pretty-printing"""
return xpretty(expr, order=order, use_unicode=False, wrap_line=False)
def upretty(expr, order=None):
"""Unicode pretty-printing"""
return xpretty(expr, order=order, use_unicode=True, wrap_line=False)
def test_pretty_ascii_str():
assert pretty( 'xxx' ) == 'xxx'
assert pretty( "xxx" ) == 'xxx'
assert pretty( 'xxx\'xxx' ) == 'xxx\'xxx'
assert pretty( 'xxx"xxx' ) == 'xxx\"xxx'
assert pretty( 'xxx\"xxx' ) == 'xxx\"xxx'
assert pretty( "xxx'xxx" ) == 'xxx\'xxx'
assert pretty( "xxx\'xxx" ) == 'xxx\'xxx'
assert pretty( "xxx\"xxx" ) == 'xxx\"xxx'
assert pretty( "xxx\"xxx\'xxx" ) == 'xxx"xxx\'xxx'
assert pretty( "xxx\nxxx" ) == 'xxx\nxxx'
def test_pretty_unicode_str():
assert pretty( u'xxx' ) == u'xxx'
assert pretty( u'xxx' ) == u'xxx'
assert pretty( u'xxx\'xxx' ) == u'xxx\'xxx'
assert pretty( u'xxx"xxx' ) == u'xxx\"xxx'
assert pretty( u'xxx\"xxx' ) == u'xxx\"xxx'
assert pretty( u"xxx'xxx" ) == u'xxx\'xxx'
assert pretty( u"xxx\'xxx" ) == u'xxx\'xxx'
assert pretty( u"xxx\"xxx" ) == u'xxx\"xxx'
assert pretty( u"xxx\"xxx\'xxx" ) == u'xxx"xxx\'xxx'
assert pretty( u"xxx\nxxx" ) == u'xxx\nxxx'
def test_upretty_greek():
assert upretty( oo ) == u'∞'
assert upretty( Symbol('alpha^+_1') ) == u'α⁺₁'
assert upretty( Symbol('beta') ) == u'β'
assert upretty(Symbol('lambda')) == u'λ'
def test_upretty_multiindex():
assert upretty( Symbol('beta12') ) == u'β₁₂'
assert upretty( Symbol('Y00') ) == u'Y₀₀'
assert upretty( Symbol('Y_00') ) == u'Y₀₀'
assert upretty( Symbol('F^+-') ) == u'F⁺⁻'
def test_upretty_sub_super():
assert upretty( Symbol('beta_1_2') ) == u'β₁ ₂'
assert upretty( Symbol('beta^1^2') ) == u'β¹ ²'
assert upretty( Symbol('beta_1^2') ) == u'β²₁'
assert upretty( Symbol('beta_10_20') ) == u'β₁₀ ₂₀'
assert upretty( Symbol('beta_ax_gamma^i') ) == u'βⁱₐₓ ᵧ'
assert upretty( Symbol("F^1^2_3_4") ) == u'F¹ ²₃ ₄'
assert upretty( Symbol("F_1_2^3^4") ) == u'F³ ⁴₁ ₂'
assert upretty( Symbol("F_1_2_3_4") ) == u'F₁ ₂ ₃ ₄'
assert upretty( Symbol("F^1^2^3^4") ) == u'F¹ ² ³ ⁴'
def test_upretty_subs_missing_in_24():
assert upretty( Symbol('F_beta') ) == u'Fᵦ'
assert upretty( Symbol('F_gamma') ) == u'Fᵧ'
assert upretty( Symbol('F_rho') ) == u'Fᵨ'
assert upretty( Symbol('F_phi') ) == u'Fᵩ'
assert upretty( Symbol('F_chi') ) == u'Fᵪ'
assert upretty( Symbol('F_a') ) == u'Fₐ'
assert upretty( Symbol('F_e') ) == u'Fₑ'
assert upretty( Symbol('F_i') ) == u'Fᵢ'
assert upretty( Symbol('F_o') ) == u'Fₒ'
assert upretty( Symbol('F_u') ) == u'Fᵤ'
assert upretty( Symbol('F_r') ) == u'Fᵣ'
assert upretty( Symbol('F_v') ) == u'Fᵥ'
assert upretty( Symbol('F_x') ) == u'Fₓ'
@XFAIL
def test_missing_in_2X_issue_9047():
assert upretty( Symbol('F_h') ) == u'Fₕ'
assert upretty( Symbol('F_k') ) == u'Fₖ'
assert upretty( Symbol('F_l') ) == u'Fₗ'
assert upretty( Symbol('F_m') ) == u'Fₘ'
assert upretty( Symbol('F_n') ) == u'Fₙ'
assert upretty( Symbol('F_p') ) == u'Fₚ'
assert upretty( Symbol('F_s') ) == u'Fₛ'
assert upretty( Symbol('F_t') ) == u'Fₜ'
def test_upretty_modifiers():
# Accents
assert upretty( Symbol('Fmathring') ) == u'F̊'
assert upretty( Symbol('Fddddot') ) == u'F̈̈'
assert upretty( Symbol('Fdddot') ) == u'F̈̇'
assert upretty( Symbol('Fddot') ) == u'F̈'
assert upretty( Symbol('Fdot') ) == u'Ḟ'
assert upretty( Symbol('Fcheck') ) == u'F̌'
assert upretty( Symbol('Fbreve') ) == u'F̆'
assert upretty( Symbol('Facute') ) == u'F́'
assert upretty( Symbol('Fgrave') ) == u'F̀'
assert upretty( Symbol('Ftilde') ) == u'F̃'
assert upretty( Symbol('Fhat') ) == u'F̂'
assert upretty( Symbol('Fbar') ) == u'F̅'
assert upretty( Symbol('Fvec') ) == u'F⃗'
assert upretty( Symbol('Fprime') ) == u'F′'
assert upretty( Symbol('Fprm') ) == u'F′'
# No faces are actually implemented, but test to make sure the modifiers are stripped
assert upretty( Symbol('Fbold') ) == u'Fbold'
assert upretty( Symbol('Fbm') ) == u'Fbm'
assert upretty( Symbol('Fcal') ) == u'Fcal'
assert upretty( Symbol('Fscr') ) == u'Fscr'
assert upretty( Symbol('Ffrak') ) == u'Ffrak'
# Brackets
assert upretty( Symbol('Fnorm') ) == u'‖F‖'
assert upretty( Symbol('Favg') ) == u'⟨F⟩'
assert upretty( Symbol('Fabs') ) == u'|F|'
assert upretty( Symbol('Fmag') ) == u'|F|'
# Combinations
assert upretty( Symbol('xvecdot') ) == u'x⃗̇'
assert upretty( Symbol('xDotVec') ) == u'ẋ⃗'
assert upretty( Symbol('xHATNorm') ) == u'‖x̂‖'
assert upretty( Symbol('xMathring_yCheckPRM__zbreveAbs') ) == u'x̊_y̌′__|z̆|'
assert upretty( Symbol('alphadothat_nVECDOT__tTildePrime') ) == u'α̇̂_n⃗̇__t̃′'
assert upretty( Symbol('x_dot') ) == u'x_dot'
assert upretty( Symbol('x__dot') ) == u'x__dot'
def test_pretty_Cycle():
from sympy.combinatorics.permutations import Cycle
assert pretty(Cycle(1, 2)) == '(1 2)'
assert pretty(Cycle(2)) == '(2)'
assert pretty(Cycle(1, 3)(4, 5)) == '(1 3)(4 5)'
assert pretty(Cycle()) == '()'
def test_pretty_basic():
assert pretty( -Rational(1)/2 ) == '-1/2'
assert pretty( -Rational(13)/22 ) == \
"""\
-13 \n\
----\n\
22 \
"""
expr = oo
ascii_str = \
"""\
oo\
"""
ucode_str = \
u("""\
∞\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (x**2)
ascii_str = \
"""\
2\n\
x \
"""
ucode_str = \
u("""\
2\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 1/x
ascii_str = \
"""\
1\n\
-\n\
x\
"""
ucode_str = \
u("""\
1\n\
─\n\
x\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
# not the same as 1/x
expr = x**-1.0
ascii_str = \
"""\
-1.0\n\
x \
"""
ucode_str = \
("""\
-1.0\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
# see issue #2860
expr = Pow(S(2), -1.0, evaluate=False)
ascii_str = \
"""\
-1.0\n\
2 \
"""
ucode_str = \
("""\
-1.0\n\
2 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = y*x**-2
ascii_str = \
"""\
y \n\
--\n\
2\n\
x \
"""
ucode_str = \
u("""\
y \n\
──\n\
2\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = x**Rational(-5, 2)
ascii_str = \
"""\
1 \n\
----\n\
5/2\n\
x \
"""
ucode_str = \
u("""\
1 \n\
────\n\
5/2\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (-2)**x
ascii_str = \
"""\
x\n\
(-2) \
"""
ucode_str = \
u("""\
x\n\
(-2) \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
# See issue 4923
expr = Pow(3, 1, evaluate=False)
ascii_str = \
"""\
1\n\
3 \
"""
ucode_str = \
u("""\
1\n\
3 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (x**2 + x + 1)
ascii_str_1 = \
"""\
2\n\
1 + x + x \
"""
ascii_str_2 = \
"""\
2 \n\
x + x + 1\
"""
ascii_str_3 = \
"""\
2 \n\
x + 1 + x\
"""
ucode_str_1 = \
u("""\
2\n\
1 + x + x \
""")
ucode_str_2 = \
u("""\
2 \n\
x + x + 1\
""")
ucode_str_3 = \
u("""\
2 \n\
x + 1 + x\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2, ascii_str_3]
assert upretty(expr) in [ucode_str_1, ucode_str_2, ucode_str_3]
expr = 1 - x
ascii_str_1 = \
"""\
1 - x\
"""
ascii_str_2 = \
"""\
-x + 1\
"""
ucode_str_1 = \
u("""\
1 - x\
""")
ucode_str_2 = \
u("""\
-x + 1\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = 1 - 2*x
ascii_str_1 = \
"""\
1 - 2*x\
"""
ascii_str_2 = \
"""\
-2*x + 1\
"""
ucode_str_1 = \
u("""\
1 - 2⋅x\
""")
ucode_str_2 = \
u("""\
-2⋅x + 1\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = x/y
ascii_str = \
"""\
x\n\
-\n\
y\
"""
ucode_str = \
u("""\
x\n\
─\n\
y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -x/y
ascii_str = \
"""\
-x \n\
---\n\
y \
"""
ucode_str = \
u("""\
-x \n\
───\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (x + 2)/y
ascii_str_1 = \
"""\
2 + x\n\
-----\n\
y \
"""
ascii_str_2 = \
"""\
x + 2\n\
-----\n\
y \
"""
ucode_str_1 = \
u("""\
2 + x\n\
─────\n\
y \
""")
ucode_str_2 = \
u("""\
x + 2\n\
─────\n\
y \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = (1 + x)*y
ascii_str_1 = \
"""\
y*(1 + x)\
"""
ascii_str_2 = \
"""\
(1 + x)*y\
"""
ascii_str_3 = \
"""\
y*(x + 1)\
"""
ucode_str_1 = \
u("""\
y⋅(1 + x)\
""")
ucode_str_2 = \
u("""\
(1 + x)⋅y\
""")
ucode_str_3 = \
u("""\
y⋅(x + 1)\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2, ascii_str_3]
assert upretty(expr) in [ucode_str_1, ucode_str_2, ucode_str_3]
# Test for correct placement of the negative sign
expr = -5*x/(x + 10)
ascii_str_1 = \
"""\
-5*x \n\
------\n\
10 + x\
"""
ascii_str_2 = \
"""\
-5*x \n\
------\n\
x + 10\
"""
ucode_str_1 = \
u("""\
-5⋅x \n\
──────\n\
10 + x\
""")
ucode_str_2 = \
u("""\
-5⋅x \n\
──────\n\
x + 10\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = -S(1)/2 - 3*x
ascii_str = \
"""\
-3*x - 1/2\
"""
ucode_str = \
u("""\
-3⋅x - 1/2\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = S(1)/2 - 3*x
ascii_str = \
"""\
-3*x + 1/2\
"""
ucode_str = \
u("""\
-3⋅x + 1/2\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -S(1)/2 - 3*x/2
ascii_str = \
"""\
3*x 1\n\
- --- - -\n\
2 2\
"""
ucode_str = \
u("""\
3⋅x 1\n\
- ─── - ─\n\
2 2\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = S(1)/2 - 3*x/2
ascii_str = \
"""\
3*x 1\n\
- --- + -\n\
2 2\
"""
ucode_str = \
u("""\
3⋅x 1\n\
- ─── + ─\n\
2 2\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_negative_fractions():
expr = -x/y
ascii_str =\
"""\
-x \n\
---\n\
y \
"""
ucode_str =\
u("""\
-x \n\
───\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -x*z/y
ascii_str =\
"""\
-x*z \n\
-----\n\
y \
"""
ucode_str =\
u("""\
-x⋅z \n\
─────\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = x**2/y
ascii_str =\
"""\
2\n\
x \n\
--\n\
y \
"""
ucode_str =\
u("""\
2\n\
x \n\
──\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -x**2/y
ascii_str =\
"""\
2 \n\
-x \n\
----\n\
y \
"""
ucode_str =\
u("""\
2 \n\
-x \n\
────\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -x/(y*z)
ascii_str =\
"""\
-x \n\
---\n\
y*z\
"""
ucode_str =\
u("""\
-x \n\
───\n\
y⋅z\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -a/y**2
ascii_str =\
"""\
-a \n\
---\n\
2\n\
y \
"""
ucode_str =\
u("""\
-a \n\
───\n\
2\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = y**(-a/b)
ascii_str =\
"""\
-a \n\
---\n\
b \n\
y \
"""
ucode_str =\
u("""\
-a \n\
───\n\
b \n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -1/y**2
ascii_str =\
"""\
-1 \n\
---\n\
2\n\
y \
"""
ucode_str =\
u("""\
-1 \n\
───\n\
2\n\
y \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -10/b**2
ascii_str =\
"""\
-10 \n\
----\n\
2 \n\
b \
"""
ucode_str =\
u("""\
-10 \n\
────\n\
2 \n\
b \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Rational(-200, 37)
ascii_str =\
"""\
-200 \n\
-----\n\
37 \
"""
ucode_str =\
u("""\
-200 \n\
─────\n\
37 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_issue_5524():
assert pretty(-(-x + 5)*(-x - 2*sqrt(2) + 5) - (-y + 5)*(-y + 5)) == \
"""\
/ ___ \\ 2\n\
(x - 5)*\\-x - 2*\\/ 2 + 5/ - (-y + 5) \
"""
assert upretty(-(-x + 5)*(-x - 2*sqrt(2) + 5) - (-y + 5)*(-y + 5)) == \
u("""\
2\n\
(x - 5)⋅(-x - 2⋅√2 + 5) - (-y + 5) \
""")
def test_pretty_ordering():
assert pretty(x**2 + x + 1, order='lex') == \
"""\
2 \n\
x + x + 1\
"""
assert pretty(x**2 + x + 1, order='rev-lex') == \
"""\
2\n\
1 + x + x \
"""
assert pretty(1 - x, order='lex') == '-x + 1'
assert pretty(1 - x, order='rev-lex') == '1 - x'
assert pretty(1 - 2*x, order='lex') == '-2*x + 1'
assert pretty(1 - 2*x, order='rev-lex') == '1 - 2*x'
f = 2*x**4 + y**2 - x**2 + y**3
assert pretty(f, order=None) == \
"""\
4 2 3 2\n\
2*x - x + y + y \
"""
assert pretty(f, order='lex') == \
"""\
4 2 3 2\n\
2*x - x + y + y \
"""
assert pretty(f, order='rev-lex') == \
"""\
2 3 2 4\n\
y + y - x + 2*x \
"""
expr = x - x**3/6 + x**5/120 + O(x**6)
ascii_str = \
"""\
3 5 \n\
x x / 6\\\n\
x - -- + --- + O\\x /\n\
6 120 \
"""
ucode_str = \
u("""\
3 5 \n\
x x ⎛ 6⎞\n\
x - ── + ─── + O⎝x ⎠\n\
6 120 \
""")
assert pretty(expr, order=None) == ascii_str
assert upretty(expr, order=None) == ucode_str
assert pretty(expr, order='lex') == ascii_str
assert upretty(expr, order='lex') == ucode_str
assert pretty(expr, order='rev-lex') == ascii_str
assert upretty(expr, order='rev-lex') == ucode_str
def test_EulerGamma():
assert pretty(EulerGamma) == str(EulerGamma) == "EulerGamma"
assert upretty(EulerGamma) == u"γ"
def test_GoldenRatio():
assert pretty(GoldenRatio) == str(GoldenRatio) == "GoldenRatio"
assert upretty(GoldenRatio) == u"φ"
def test_pretty_relational():
expr = Eq(x, y)
ascii_str = \
"""\
x = y\
"""
ucode_str = \
u("""\
x = y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Lt(x, y)
ascii_str = \
"""\
x < y\
"""
ucode_str = \
u("""\
x < y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Gt(x, y)
ascii_str = \
"""\
x > y\
"""
ucode_str = \
u("""\
x > y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Le(x, y)
ascii_str = \
"""\
x <= y\
"""
ucode_str = \
u("""\
x ≤ y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Ge(x, y)
ascii_str = \
"""\
x >= y\
"""
ucode_str = \
u("""\
x ≥ y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Ne(x/(y + 1), y**2)
ascii_str_1 = \
"""\
x 2\n\
----- != y \n\
1 + y \
"""
ascii_str_2 = \
"""\
x 2\n\
----- != y \n\
y + 1 \
"""
ucode_str_1 = \
u("""\
x 2\n\
───── ≠ y \n\
1 + y \
""")
ucode_str_2 = \
u("""\
x 2\n\
───── ≠ y \n\
y + 1 \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
def test_Assignment():
expr = Assignment(x, y)
ascii_str = \
"""\
x := y\
"""
ucode_str = \
u("""\
x := y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_AugmentedAssignment():
expr = AddAugmentedAssignment(x, y)
ascii_str = \
"""\
x += y\
"""
ucode_str = \
u("""\
x += y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = SubAugmentedAssignment(x, y)
ascii_str = \
"""\
x -= y\
"""
ucode_str = \
u("""\
x -= y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = MulAugmentedAssignment(x, y)
ascii_str = \
"""\
x *= y\
"""
ucode_str = \
u("""\
x *= y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = DivAugmentedAssignment(x, y)
ascii_str = \
"""\
x /= y\
"""
ucode_str = \
u("""\
x /= y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = ModAugmentedAssignment(x, y)
ascii_str = \
"""\
x %= y\
"""
ucode_str = \
u("""\
x %= y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_issue_7117():
# See also issue #5031 (hence the evaluate=False in these).
e = Eq(x + 1, x/2)
q = Mul(2, e, evaluate=False)
assert upretty(q) == u("""\
⎛ x⎞\n\
2⋅⎜x + 1 = ─⎟\n\
⎝ 2⎠\
""")
q = Add(e, 6, evaluate=False)
assert upretty(q) == u("""\
⎛ x⎞\n\
6 + ⎜x + 1 = ─⎟\n\
⎝ 2⎠\
""")
q = Pow(e, 2, evaluate=False)
assert upretty(q) == u("""\
2\n\
⎛ x⎞ \n\
⎜x + 1 = ─⎟ \n\
⎝ 2⎠ \
""")
e2 = Eq(x, 2)
q = Mul(e, e2, evaluate=False)
assert upretty(q) == u("""\
⎛ x⎞ \n\
⎜x + 1 = ─⎟⋅(x = 2)\n\
⎝ 2⎠ \
""")
def test_pretty_rational():
expr = y*x**-2
ascii_str = \
"""\
y \n\
--\n\
2\n\
x \
"""
ucode_str = \
u("""\
y \n\
──\n\
2\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = y**Rational(3, 2) * x**Rational(-5, 2)
ascii_str = \
"""\
3/2\n\
y \n\
----\n\
5/2\n\
x \
"""
ucode_str = \
u("""\
3/2\n\
y \n\
────\n\
5/2\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = sin(x)**3/tan(x)**2
ascii_str = \
"""\
3 \n\
sin (x)\n\
-------\n\
2 \n\
tan (x)\
"""
ucode_str = \
u("""\
3 \n\
sin (x)\n\
───────\n\
2 \n\
tan (x)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_functions():
"""Tests for Abs, conjugate, exp, function braces, and factorial."""
expr = (2*x + exp(x))
ascii_str_1 = \
"""\
x\n\
2*x + e \
"""
ascii_str_2 = \
"""\
x \n\
e + 2*x\
"""
ucode_str_1 = \
u("""\
x\n\
2⋅x + ℯ \
""")
ucode_str_2 = \
u("""\
x \n\
ℯ + 2⋅x\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = Abs(x)
ascii_str = \
"""\
|x|\
"""
ucode_str = \
u("""\
│x│\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Abs(x/(x**2 + 1))
ascii_str_1 = \
"""\
| x |\n\
|------|\n\
| 2|\n\
|1 + x |\
"""
ascii_str_2 = \
"""\
| x |\n\
|------|\n\
| 2 |\n\
|x + 1|\
"""
ucode_str_1 = \
u("""\
│ x │\n\
│──────│\n\
│ 2│\n\
│1 + x │\
""")
ucode_str_2 = \
u("""\
│ x │\n\
│──────│\n\
│ 2 │\n\
│x + 1│\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = Abs(1 / (y - Abs(x)))
ascii_str = \
"""\
| 1 |\n\
|-------|\n\
|y - |x||\
"""
ucode_str = \
u("""\
│ 1 │\n\
│───────│\n\
│y - │x││\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
n = Symbol('n', integer=True)
expr = factorial(n)
ascii_str = \
"""\
n!\
"""
ucode_str = \
u("""\
n!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial(2*n)
ascii_str = \
"""\
(2*n)!\
"""
ucode_str = \
u("""\
(2⋅n)!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial(factorial(factorial(n)))
ascii_str = \
"""\
((n!)!)!\
"""
ucode_str = \
u("""\
((n!)!)!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial(n + 1)
ascii_str_1 = \
"""\
(1 + n)!\
"""
ascii_str_2 = \
"""\
(n + 1)!\
"""
ucode_str_1 = \
u("""\
(1 + n)!\
""")
ucode_str_2 = \
u("""\
(n + 1)!\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = subfactorial(n)
ascii_str = \
"""\
!n\
"""
ucode_str = \
u("""\
!n\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = subfactorial(2*n)
ascii_str = \
"""\
!(2*n)\
"""
ucode_str = \
u("""\
!(2⋅n)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
n = Symbol('n', integer=True)
expr = factorial2(n)
ascii_str = \
"""\
n!!\
"""
ucode_str = \
u("""\
n!!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial2(2*n)
ascii_str = \
"""\
(2*n)!!\
"""
ucode_str = \
u("""\
(2⋅n)!!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial2(factorial2(factorial2(n)))
ascii_str = \
"""\
((n!!)!!)!!\
"""
ucode_str = \
u("""\
((n!!)!!)!!\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = factorial2(n + 1)
ascii_str_1 = \
"""\
(1 + n)!!\
"""
ascii_str_2 = \
"""\
(n + 1)!!\
"""
ucode_str_1 = \
u("""\
(1 + n)!!\
""")
ucode_str_2 = \
u("""\
(n + 1)!!\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = 2*binomial(n, k)
ascii_str = \
"""\
/n\\\n\
2*| |\n\
\\k/\
"""
ucode_str = \
u("""\
⎛n⎞\n\
2⋅⎜ ⎟\n\
⎝k⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2*binomial(2*n, k)
ascii_str = \
"""\
/2*n\\\n\
2*| |\n\
\\ k /\
"""
ucode_str = \
u("""\
⎛2⋅n⎞\n\
2⋅⎜ ⎟\n\
⎝ k ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2*binomial(n**2, k)
ascii_str = \
"""\
/ 2\\\n\
|n |\n\
2*| |\n\
\\k /\
"""
ucode_str = \
u("""\
⎛ 2⎞\n\
⎜n ⎟\n\
2⋅⎜ ⎟\n\
⎝k ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = catalan(n)
ascii_str = \
"""\
C \n\
n\
"""
ucode_str = \
u("""\
C \n\
n\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = conjugate(x)
ascii_str = \
"""\
_\n\
x\
"""
ucode_str = \
u("""\
_\n\
x\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
f = Function('f')
expr = conjugate(f(x + 1))
ascii_str_1 = \
"""\
________\n\
f(1 + x)\
"""
ascii_str_2 = \
"""\
________\n\
f(x + 1)\
"""
ucode_str_1 = \
u("""\
________\n\
f(1 + x)\
""")
ucode_str_2 = \
u("""\
________\n\
f(x + 1)\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = f(x)
ascii_str = \
"""\
f(x)\
"""
ucode_str = \
u("""\
f(x)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = f(x, y)
ascii_str = \
"""\
f(x, y)\
"""
ucode_str = \
u("""\
f(x, y)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = f(x/(y + 1), y)
ascii_str_1 = \
"""\
/ x \\\n\
f|-----, y|\n\
\\1 + y /\
"""
ascii_str_2 = \
"""\
/ x \\\n\
f|-----, y|\n\
\\y + 1 /\
"""
ucode_str_1 = \
u("""\
⎛ x ⎞\n\
f⎜─────, y⎟\n\
⎝1 + y ⎠\
""")
ucode_str_2 = \
u("""\
⎛ x ⎞\n\
f⎜─────, y⎟\n\
⎝y + 1 ⎠\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = f(x**x**x**x**x**x)
ascii_str = \
"""\
/ / / / / x\\\\\\\\\\
| | | | \\x /||||
| | | \\x /|||
| | \\x /||
| \\x /|
f\\x /\
"""
ucode_str = \
u("""\
⎛ ⎛ ⎛ ⎛ ⎛ x⎞⎞⎞⎞⎞
⎜ ⎜ ⎜ ⎜ ⎝x ⎠⎟⎟⎟⎟
⎜ ⎜ ⎜ ⎝x ⎠⎟⎟⎟
⎜ ⎜ ⎝x ⎠⎟⎟
⎜ ⎝x ⎠⎟
f⎝x ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = sin(x)**2
ascii_str = \
"""\
2 \n\
sin (x)\
"""
ucode_str = \
u("""\
2 \n\
sin (x)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = conjugate(a + b*I)
ascii_str = \
"""\
_ _\n\
a - I*b\
"""
ucode_str = \
u("""\
_ _\n\
a - ⅈ⋅b\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = conjugate(exp(a + b*I))
ascii_str = \
"""\
_ _\n\
a - I*b\n\
e \
"""
ucode_str = \
u("""\
_ _\n\
a - ⅈ⋅b\n\
ℯ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = conjugate( f(1 + conjugate(f(x))) )
ascii_str_1 = \
"""\
___________\n\
/ ____\\\n\
f\\1 + f(x)/\
"""
ascii_str_2 = \
"""\
___________\n\
/____ \\\n\
f\\f(x) + 1/\
"""
ucode_str_1 = \
u("""\
___________\n\
⎛ ____⎞\n\
f⎝1 + f(x)⎠\
""")
ucode_str_2 = \
u("""\
___________\n\
⎛____ ⎞\n\
f⎝f(x) + 1⎠\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = f(x/(y + 1), y)
ascii_str_1 = \
"""\
/ x \\\n\
f|-----, y|\n\
\\1 + y /\
"""
ascii_str_2 = \
"""\
/ x \\\n\
f|-----, y|\n\
\\y + 1 /\
"""
ucode_str_1 = \
u("""\
⎛ x ⎞\n\
f⎜─────, y⎟\n\
⎝1 + y ⎠\
""")
ucode_str_2 = \
u("""\
⎛ x ⎞\n\
f⎜─────, y⎟\n\
⎝y + 1 ⎠\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = floor(1 / (y - floor(x)))
ascii_str = \
"""\
/ 1 \\\n\
floor|------------|\n\
\\y - floor(x)/\
"""
ucode_str = \
u("""\
⎢ 1 ⎥\n\
⎢───────⎥\n\
⎣y - ⌊x⌋⎦\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = ceiling(1 / (y - ceiling(x)))
ascii_str = \
"""\
/ 1 \\\n\
ceiling|--------------|\n\
\\y - ceiling(x)/\
"""
ucode_str = \
u("""\
⎡ 1 ⎤\n\
⎢───────⎥\n\
⎢y - ⌈x⌉⎥\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = euler(n)
ascii_str = \
"""\
E \n\
n\
"""
ucode_str = \
u("""\
E \n\
n\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = euler(1/(1 + 1/(1 + 1/n)))
ascii_str = \
"""\
E \n\
1 \n\
---------\n\
1 \n\
1 + -----\n\
1\n\
1 + -\n\
n\
"""
ucode_str = \
u("""\
E \n\
1 \n\
─────────\n\
1 \n\
1 + ─────\n\
1\n\
1 + ─\n\
n\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = euler(n, x)
ascii_str = \
"""\
E (x)\n\
n \
"""
ucode_str = \
u("""\
E (x)\n\
n \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = euler(n, x/2)
ascii_str = \
"""\
/x\\\n\
E |-|\n\
n\\2/\
"""
ucode_str = \
u("""\
⎛x⎞\n\
E ⎜─⎟\n\
n⎝2⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_sqrt():
expr = sqrt(2)
ascii_str = \
"""\
___\n\
\\/ 2 \
"""
ucode_str = \
u"√2"
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2**Rational(1, 3)
ascii_str = \
"""\
3 ___\n\
\\/ 2 \
"""
ucode_str = \
u("""\
3 ___\n\
╲╱ 2 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2**Rational(1, 1000)
ascii_str = \
"""\
1000___\n\
\\/ 2 \
"""
ucode_str = \
u("""\
1000___\n\
╲╱ 2 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = sqrt(x**2 + 1)
ascii_str = \
"""\
________\n\
/ 2 \n\
\\/ x + 1 \
"""
ucode_str = \
u("""\
________\n\
╱ 2 \n\
╲╱ x + 1 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (1 + sqrt(5))**Rational(1, 3)
ascii_str = \
"""\
___________\n\
3 / ___ \n\
\\/ 1 + \\/ 5 \
"""
ucode_str = \
u("""\
3 ________\n\
╲╱ 1 + √5 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2**(1/x)
ascii_str = \
"""\
x ___\n\
\\/ 2 \
"""
ucode_str = \
u("""\
x ___\n\
╲╱ 2 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = sqrt(2 + pi)
ascii_str = \
"""\
________\n\
\\/ 2 + pi \
"""
ucode_str = \
u("""\
_______\n\
╲╱ 2 + π \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (2 + (
1 + x**2)/(2 + x))**Rational(1, 4) + (1 + x**Rational(1, 1000))/sqrt(3 + x**2)
ascii_str = \
"""\
____________ \n\
/ 2 1000___ \n\
/ x + 1 \\/ x + 1\n\
4 / 2 + ------ + -----------\n\
\\/ x + 2 ________\n\
/ 2 \n\
\\/ x + 3 \
"""
ucode_str = \
u("""\
____________ \n\
╱ 2 1000___ \n\
╱ x + 1 ╲╱ x + 1\n\
4 ╱ 2 + ────── + ───────────\n\
╲╱ x + 2 ________\n\
╱ 2 \n\
╲╱ x + 3 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_sqrt_char_knob():
# See PR #9234.
expr = sqrt(2)
ucode_str1 = \
u("""\
___\n\
╲╱ 2 \
""")
ucode_str2 = \
u"√2"
assert xpretty(expr, use_unicode=True,
use_unicode_sqrt_char=False) == ucode_str1
assert xpretty(expr, use_unicode=True,
use_unicode_sqrt_char=True) == ucode_str2
def test_pretty_sqrt_longsymbol_no_sqrt_char():
# Do not use unicode sqrt char for long symbols (see PR #9234).
expr = sqrt(Symbol('C1'))
ucode_str = \
u("""\
____\n\
╲╱ C₁ \
""")
assert upretty(expr) == ucode_str
def test_pretty_KroneckerDelta():
x, y = symbols("x, y")
expr = KroneckerDelta(x, y)
ascii_str = \
"""\
d \n\
x,y\
"""
ucode_str = \
u("""\
δ \n\
x,y\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_product():
n, m, k, l = symbols('n m k l')
f = symbols('f', cls=Function)
expr = Product(f((n/3)**2), (n, k**2, l))
unicode_str = \
u("""\
l \n\
┬────────┬ \n\
│ │ ⎛ 2⎞\n\
│ │ ⎜n ⎟\n\
│ │ f⎜──⎟\n\
│ │ ⎝9 ⎠\n\
│ │ \n\
2 \n\
n = k """)
ascii_str = \
"""\
l \n\
__________ \n\
| | / 2\\\n\
| | |n |\n\
| | f|--|\n\
| | \\9 /\n\
| | \n\
2 \n\
n = k """
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Product(f((n/3)**2), (n, k**2, l), (l, 1, m))
unicode_str = \
u("""\
m l \n\
┬────────┬ ┬────────┬ \n\
│ │ │ │ ⎛ 2⎞\n\
│ │ │ │ ⎜n ⎟\n\
│ │ │ │ f⎜──⎟\n\
│ │ │ │ ⎝9 ⎠\n\
│ │ │ │ \n\
l = 1 2 \n\
n = k """)
ascii_str = \
"""\
m l \n\
__________ __________ \n\
| | | | / 2\\\n\
| | | | |n |\n\
| | | | f|--|\n\
| | | | \\9 /\n\
| | | | \n\
l = 1 2 \n\
n = k """
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
def test_pretty_lambda():
# S.IdentityFunction is a special case
expr = Lambda(y, y)
assert pretty(expr) == "x -> x"
assert upretty(expr) == u"x ↦ x"
expr = Lambda(x, x+1)
assert pretty(expr) == "x -> x + 1"
assert upretty(expr) == u"x ↦ x + 1"
expr = Lambda(x, x**2)
ascii_str = \
"""\
2\n\
x -> x \
"""
ucode_str = \
u("""\
2\n\
x ↦ x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Lambda(x, x**2)**2
ascii_str = \
"""\
2
/ 2\\ \n\
\\x -> x / \
"""
ucode_str = \
u("""\
2
⎛ 2⎞ \n\
⎝x ↦ x ⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Lambda((x, y), x)
ascii_str = "(x, y) -> x"
ucode_str = u"(x, y) ↦ x"
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Lambda((x, y), x**2)
ascii_str = \
"""\
2\n\
(x, y) -> x \
"""
ucode_str = \
u("""\
2\n\
(x, y) ↦ x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_order():
expr = O(1)
ascii_str = \
"""\
O(1)\
"""
ucode_str = \
u("""\
O(1)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = O(1/x)
ascii_str = \
"""\
/1\\\n\
O|-|\n\
\\x/\
"""
ucode_str = \
u("""\
⎛1⎞\n\
O⎜─⎟\n\
⎝x⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = O(x**2 + y**2)
ascii_str = \
"""\
/ 2 2 \\\n\
O\\x + y ; (x, y) -> (0, 0)/\
"""
ucode_str = \
u("""\
⎛ 2 2 ⎞\n\
O⎝x + y ; (x, y) → (0, 0)⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = O(1, (x, oo))
ascii_str = \
"""\
O(1; x -> oo)\
"""
ucode_str = \
u("""\
O(1; x → ∞)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = O(1/x, (x, oo))
ascii_str = \
"""\
/1 \\\n\
O|-; x -> oo|\n\
\\x /\
"""
ucode_str = \
u("""\
⎛1 ⎞\n\
O⎜─; x → ∞⎟\n\
⎝x ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = O(x**2 + y**2, (x, oo), (y, oo))
ascii_str = \
"""\
/ 2 2 \\\n\
O\\x + y ; (x, y) -> (oo, oo)/\
"""
ucode_str = \
u("""\
⎛ 2 2 ⎞\n\
O⎝x + y ; (x, y) → (∞, ∞)⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_derivatives():
# Simple
expr = Derivative(log(x), x, evaluate=False)
ascii_str = \
"""\
d \n\
--(log(x))\n\
dx \
"""
ucode_str = \
u("""\
d \n\
──(log(x))\n\
dx \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Derivative(log(x), x, evaluate=False) + x
ascii_str_1 = \
"""\
d \n\
x + --(log(x))\n\
dx \
"""
ascii_str_2 = \
"""\
d \n\
--(log(x)) + x\n\
dx \
"""
ucode_str_1 = \
u("""\
d \n\
x + ──(log(x))\n\
dx \
""")
ucode_str_2 = \
u("""\
d \n\
──(log(x)) + x\n\
dx \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
# basic partial derivatives
expr = Derivative(log(x + y) + x, x)
ascii_str_1 = \
"""\
d \n\
--(log(x + y) + x)\n\
dx \
"""
ascii_str_2 = \
"""\
d \n\
--(x + log(x + y))\n\
dx \
"""
ucode_str_1 = \
u("""\
∂ \n\
──(log(x + y) + x)\n\
∂x \
""")
ucode_str_2 = \
u("""\
∂ \n\
──(x + log(x + y))\n\
∂x \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2], upretty(expr)
# Multiple symbols
expr = Derivative(log(x) + x**2, x, y)
ascii_str_1 = \
"""\
2 \n\
d / 2\\\n\
-----\\log(x) + x /\n\
dy dx \
"""
ascii_str_2 = \
"""\
2 \n\
d / 2 \\\n\
-----\\x + log(x)/\n\
dy dx \
"""
ucode_str_1 = \
u("""\
2 \n\
d ⎛ 2⎞\n\
─────⎝log(x) + x ⎠\n\
dy dx \
""")
ucode_str_2 = \
u("""\
2 \n\
d ⎛ 2 ⎞\n\
─────⎝x + log(x)⎠\n\
dy dx \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = Derivative(2*x*y, y, x) + x**2
ascii_str_1 = \
"""\
2 \n\
d 2\n\
-----(2*x*y) + x \n\
dx dy \
"""
ascii_str_2 = \
"""\
2 \n\
2 d \n\
x + -----(2*x*y)\n\
dx dy \
"""
ucode_str_1 = \
u("""\
2 \n\
∂ 2\n\
─────(2⋅x⋅y) + x \n\
∂x ∂y \
""")
ucode_str_2 = \
u("""\
2 \n\
2 ∂ \n\
x + ─────(2⋅x⋅y)\n\
∂x ∂y \
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = Derivative(2*x*y, x, x)
ascii_str = \
"""\
2 \n\
d \n\
---(2*x*y)\n\
2 \n\
dx \
"""
ucode_str = \
u("""\
2 \n\
∂ \n\
───(2⋅x⋅y)\n\
2 \n\
∂x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Derivative(2*x*y, x, 17)
ascii_str = \
"""\
17 \n\
d \n\
----(2*x*y)\n\
17 \n\
dx \
"""
ucode_str = \
u("""\
17 \n\
∂ \n\
────(2⋅x⋅y)\n\
17 \n\
∂x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Derivative(2*x*y, x, x, y)
ascii_str = \
"""\
3 \n\
d \n\
------(2*x*y)\n\
2 \n\
dy dx \
"""
ucode_str = \
u("""\
3 \n\
∂ \n\
──────(2⋅x⋅y)\n\
2 \n\
∂y ∂x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
# Greek letters
alpha = Symbol('alpha')
beta = Function('beta')
expr = beta(alpha).diff(alpha)
ascii_str = \
"""\
d \n\
------(beta(alpha))\n\
dalpha \
"""
ucode_str = \
u("""\
d \n\
──(β(α))\n\
dα \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Derivative(f(x), (x, n))
ascii_str = \
"""\
n \n\
d \n\
---(f(x))\n\
n \n\
dx \
"""
ucode_str = \
u("""\
n \n\
d \n\
───(f(x))\n\
n \n\
dx \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_integrals():
expr = Integral(log(x), x)
ascii_str = \
"""\
/ \n\
| \n\
| log(x) dx\n\
| \n\
/ \
"""
ucode_str = \
u("""\
⌠ \n\
⎮ log(x) dx\n\
⌡ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(x**2, x)
ascii_str = \
"""\
/ \n\
| \n\
| 2 \n\
| x dx\n\
| \n\
/ \
"""
ucode_str = \
u("""\
⌠ \n\
⎮ 2 \n\
⎮ x dx\n\
⌡ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral((sin(x))**2 / (tan(x))**2)
ascii_str = \
"""\
/ \n\
| \n\
| 2 \n\
| sin (x) \n\
| ------- dx\n\
| 2 \n\
| tan (x) \n\
| \n\
/ \
"""
ucode_str = \
u("""\
⌠ \n\
⎮ 2 \n\
⎮ sin (x) \n\
⎮ ─────── dx\n\
⎮ 2 \n\
⎮ tan (x) \n\
⌡ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(x**(2**x), x)
ascii_str = \
"""\
/ \n\
| \n\
| / x\\ \n\
| \\2 / \n\
| x dx\n\
| \n\
/ \
"""
ucode_str = \
u("""\
⌠ \n\
⎮ ⎛ x⎞ \n\
⎮ ⎝2 ⎠ \n\
⎮ x dx\n\
⌡ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(x**2, (x, 1, 2))
ascii_str = \
"""\
2 \n\
/ \n\
| \n\
| 2 \n\
| x dx\n\
| \n\
/ \n\
1 \
"""
ucode_str = \
u("""\
2 \n\
⌠ \n\
⎮ 2 \n\
⎮ x dx\n\
⌡ \n\
1 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(x**2, (x, Rational(1, 2), 10))
ascii_str = \
"""\
10 \n\
/ \n\
| \n\
| 2 \n\
| x dx\n\
| \n\
/ \n\
1/2 \
"""
ucode_str = \
u("""\
10 \n\
⌠ \n\
⎮ 2 \n\
⎮ x dx\n\
⌡ \n\
1/2 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(x**2*y**2, x, y)
ascii_str = \
"""\
/ / \n\
| | \n\
| | 2 2 \n\
| | x *y dx dy\n\
| | \n\
/ / \
"""
ucode_str = \
u("""\
⌠ ⌠ \n\
⎮ ⎮ 2 2 \n\
⎮ ⎮ x ⋅y dx dy\n\
⌡ ⌡ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(sin(th)/cos(ph), (th, 0, pi), (ph, 0, 2*pi))
ascii_str = \
"""\
2*pi pi \n\
/ / \n\
| | \n\
| | sin(theta) \n\
| | ---------- d(theta) d(phi)\n\
| | cos(phi) \n\
| | \n\
/ / \n\
0 0 \
"""
ucode_str = \
u("""\
2⋅π π \n\
⌠ ⌠ \n\
⎮ ⎮ sin(θ) \n\
⎮ ⎮ ────── dθ dφ\n\
⎮ ⎮ cos(φ) \n\
⌡ ⌡ \n\
0 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_matrix():
# Empty Matrix
expr = Matrix()
ascii_str = "[]"
unicode_str = "[]"
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Matrix(2, 0, lambda i, j: 0)
ascii_str = "[]"
unicode_str = "[]"
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Matrix(0, 2, lambda i, j: 0)
ascii_str = "[]"
unicode_str = "[]"
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Matrix([[x**2 + 1, 1], [y, x + y]])
ascii_str_1 = \
"""\
[ 2 ]
[1 + x 1 ]
[ ]
[ y x + y]\
"""
ascii_str_2 = \
"""\
[ 2 ]
[x + 1 1 ]
[ ]
[ y x + y]\
"""
ucode_str_1 = \
u("""\
⎡ 2 ⎤
⎢1 + x 1 ⎥
⎢ ⎥
⎣ y x + y⎦\
""")
ucode_str_2 = \
u("""\
⎡ 2 ⎤
⎢x + 1 1 ⎥
⎢ ⎥
⎣ y x + y⎦\
""")
assert pretty(expr) in [ascii_str_1, ascii_str_2]
assert upretty(expr) in [ucode_str_1, ucode_str_2]
expr = Matrix([[x/y, y, th], [0, exp(I*k*ph), 1]])
ascii_str = \
"""\
[x ]
[- y theta]
[y ]
[ ]
[ I*k*phi ]
[0 e 1 ]\
"""
ucode_str = \
u("""\
⎡x ⎤
⎢─ y θ⎥
⎢y ⎥
⎢ ⎥
⎢ ⅈ⋅k⋅φ ⎥
⎣0 ℯ 1⎦\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_ndim_arrays():
x, y, z, w = symbols("x y z w")
for ArrayType in (ImmutableDenseNDimArray, ImmutableSparseNDimArray, MutableDenseNDimArray, MutableSparseNDimArray):
# Basic: scalar array
M = ArrayType(x)
assert pretty(M) == "x"
assert upretty(M) == "x"
M = ArrayType([[1/x, y], [z, w]])
M1 = ArrayType([1/x, y, z])
M2 = tensorproduct(M1, M)
M3 = tensorproduct(M, M)
ascii_str = \
"""\
[1 ]\n\
[- y]\n\
[x ]\n\
[ ]\n\
[z w]\
"""
ucode_str = \
u("""\
⎡1 ⎤\n\
⎢─ y⎥\n\
⎢x ⎥\n\
⎢ ⎥\n\
⎣z w⎦\
""")
assert pretty(M) == ascii_str
assert upretty(M) == ucode_str
ascii_str = \
"""\
[1 ]\n\
[- y z]\n\
[x ]\
"""
ucode_str = \
u("""\
⎡1 ⎤\n\
⎢─ y z⎥\n\
⎣x ⎦\
""")
assert pretty(M1) == ascii_str
assert upretty(M1) == ucode_str
ascii_str = \
"""\
[[1 y] ]\n\
[[-- -] [z ]]\n\
[[ 2 x] [ y 2 ] [- y*z]]\n\
[[x ] [ - y ] [x ]]\n\
[[ ] [ x ] [ ]]\n\
[[z w] [ ] [ 2 ]]\n\
[[- -] [y*z w*y] [z w*z]]\n\
[[x x] ]\
"""
ucode_str = \
u("""\
⎡⎡1 y⎤ ⎤\n\
⎢⎢── ─⎥ ⎡z ⎤⎥\n\
⎢⎢ 2 x⎥ ⎡ y 2 ⎤ ⎢─ y⋅z⎥⎥\n\
⎢⎢x ⎥ ⎢ ─ y ⎥ ⎢x ⎥⎥\n\
⎢⎢ ⎥ ⎢ x ⎥ ⎢ ⎥⎥\n\
⎢⎢z w⎥ ⎢ ⎥ ⎢ 2 ⎥⎥\n\
⎢⎢─ ─⎥ ⎣y⋅z w⋅y⎦ ⎣z w⋅z⎦⎥\n\
⎣⎣x x⎦ ⎦\
""")
assert pretty(M2) == ascii_str
assert upretty(M2) == ucode_str
ascii_str = \
"""\
[ [1 y] ]\n\
[ [-- -] ]\n\
[ [ 2 x] [ y 2 ]]\n\
[ [x ] [ - y ]]\n\
[ [ ] [ x ]]\n\
[ [z w] [ ]]\n\
[ [- -] [y*z w*y]]\n\
[ [x x] ]\n\
[ ]\n\
[[z ] [ w ]]\n\
[[- y*z] [ - w*y]]\n\
[[x ] [ x ]]\n\
[[ ] [ ]]\n\
[[ 2 ] [ 2 ]]\n\
[[z w*z] [w*z w ]]\
"""
ucode_str = \
u("""\
⎡ ⎡1 y⎤ ⎤\n\
⎢ ⎢── ─⎥ ⎥\n\
⎢ ⎢ 2 x⎥ ⎡ y 2 ⎤⎥\n\
⎢ ⎢x ⎥ ⎢ ─ y ⎥⎥\n\
⎢ ⎢ ⎥ ⎢ x ⎥⎥\n\
⎢ ⎢z w⎥ ⎢ ⎥⎥\n\
⎢ ⎢─ ─⎥ ⎣y⋅z w⋅y⎦⎥\n\
⎢ ⎣x x⎦ ⎥\n\
⎢ ⎥\n\
⎢⎡z ⎤ ⎡ w ⎤⎥\n\
⎢⎢─ y⋅z⎥ ⎢ ─ w⋅y⎥⎥\n\
⎢⎢x ⎥ ⎢ x ⎥⎥\n\
⎢⎢ ⎥ ⎢ ⎥⎥\n\
⎢⎢ 2 ⎥ ⎢ 2 ⎥⎥\n\
⎣⎣z w⋅z⎦ ⎣w⋅z w ⎦⎦\
""")
assert pretty(M3) == ascii_str
assert upretty(M3) == ucode_str
Mrow = ArrayType([[x, y, 1 / z]])
Mcolumn = ArrayType([[x], [y], [1 / z]])
Mcol2 = ArrayType([Mcolumn.tolist()])
ascii_str = \
"""\
[[ 1]]\n\
[[x y -]]\n\
[[ z]]\
"""
ucode_str = \
u("""\
⎡⎡ 1⎤⎤\n\
⎢⎢x y ─⎥⎥\n\
⎣⎣ z⎦⎦\
""")
assert pretty(Mrow) == ascii_str
assert upretty(Mrow) == ucode_str
ascii_str = \
"""\
[x]\n\
[ ]\n\
[y]\n\
[ ]\n\
[1]\n\
[-]\n\
[z]\
"""
ucode_str = \
u("""\
⎡x⎤\n\
⎢ ⎥\n\
⎢y⎥\n\
⎢ ⎥\n\
⎢1⎥\n\
⎢─⎥\n\
⎣z⎦\
""")
assert pretty(Mcolumn) == ascii_str
assert upretty(Mcolumn) == ucode_str
ascii_str = \
"""\
[[x]]\n\
[[ ]]\n\
[[y]]\n\
[[ ]]\n\
[[1]]\n\
[[-]]\n\
[[z]]\
"""
ucode_str = \
u("""\
⎡⎡x⎤⎤\n\
⎢⎢ ⎥⎥\n\
⎢⎢y⎥⎥\n\
⎢⎢ ⎥⎥\n\
⎢⎢1⎥⎥\n\
⎢⎢─⎥⎥\n\
⎣⎣z⎦⎦\
""")
assert pretty(Mcol2) == ascii_str
assert upretty(Mcol2) == ucode_str
def test_tensor_TensorProduct():
A = MatrixSymbol("A", 3, 3)
B = MatrixSymbol("B", 3, 3)
assert upretty(TensorProduct(A, B)) == "A\u2297B"
assert upretty(TensorProduct(A, B, A)) == "A\u2297B\u2297A"
def test_diffgeom_print_WedgeProduct():
from sympy.diffgeom.rn import R2
from sympy.diffgeom import WedgeProduct
wp = WedgeProduct(R2.dx, R2.dy)
assert upretty(wp) == u("ⅆ x∧ⅆ y")
def test_Adjoint():
X = MatrixSymbol('X', 2, 2)
Y = MatrixSymbol('Y', 2, 2)
assert pretty(Adjoint(X)) == " +\nX "
assert pretty(Adjoint(X + Y)) == " +\n(X + Y) "
assert pretty(Adjoint(X) + Adjoint(Y)) == " + +\nX + Y "
assert pretty(Adjoint(X*Y)) == " +\n(X*Y) "
assert pretty(Adjoint(Y)*Adjoint(X)) == " + +\nY *X "
assert pretty(Adjoint(X**2)) == " +\n/ 2\\ \n\\X / "
assert pretty(Adjoint(X)**2) == " 2\n/ +\\ \n\\X / "
assert pretty(Adjoint(Inverse(X))) == " +\n/ -1\\ \n\\X / "
assert pretty(Inverse(Adjoint(X))) == " -1\n/ +\\ \n\\X / "
assert pretty(Adjoint(Transpose(X))) == " +\n/ T\\ \n\\X / "
assert pretty(Transpose(Adjoint(X))) == " T\n/ +\\ \n\\X / "
assert upretty(Adjoint(X)) == u" †\nX "
assert upretty(Adjoint(X + Y)) == u" †\n(X + Y) "
assert upretty(Adjoint(X) + Adjoint(Y)) == u" † †\nX + Y "
assert upretty(Adjoint(X*Y)) == u" †\n(X⋅Y) "
assert upretty(Adjoint(Y)*Adjoint(X)) == u" † †\nY ⋅X "
assert upretty(Adjoint(X**2)) == \
u" †\n⎛ 2⎞ \n⎝X ⎠ "
assert upretty(Adjoint(X)**2) == \
u" 2\n⎛ †⎞ \n⎝X ⎠ "
assert upretty(Adjoint(Inverse(X))) == \
u" †\n⎛ -1⎞ \n⎝X ⎠ "
assert upretty(Inverse(Adjoint(X))) == \
u" -1\n⎛ †⎞ \n⎝X ⎠ "
assert upretty(Adjoint(Transpose(X))) == \
u" †\n⎛ T⎞ \n⎝X ⎠ "
assert upretty(Transpose(Adjoint(X))) == \
u" T\n⎛ †⎞ \n⎝X ⎠ "
def test_pretty_Trace_issue_9044():
X = Matrix([[1, 2], [3, 4]])
Y = Matrix([[2, 4], [6, 8]])
ascii_str_1 = \
"""\
/[1 2]\\
tr|[ ]|
\\[3 4]/\
"""
ucode_str_1 = \
u("""\
⎛⎡1 2⎤⎞
tr⎜⎢ ⎥⎟
⎝⎣3 4⎦⎠\
""")
ascii_str_2 = \
"""\
/[1 2]\\ /[2 4]\\
tr|[ ]| + tr|[ ]|
\\[3 4]/ \\[6 8]/\
"""
ucode_str_2 = \
u("""\
⎛⎡1 2⎤⎞ ⎛⎡2 4⎤⎞
tr⎜⎢ ⎥⎟ + tr⎜⎢ ⎥⎟
⎝⎣3 4⎦⎠ ⎝⎣6 8⎦⎠\
""")
assert pretty(Trace(X)) == ascii_str_1
assert upretty(Trace(X)) == ucode_str_1
assert pretty(Trace(X) + Trace(Y)) == ascii_str_2
assert upretty(Trace(X) + Trace(Y)) == ucode_str_2
def test_MatrixExpressions():
n = Symbol('n', integer=True)
X = MatrixSymbol('X', n, n)
assert pretty(X) == upretty(X) == "X"
Y = X[1:2:3, 4:5:6]
ascii_str = ucode_str = "X[1:3, 4:6]"
assert pretty(Y) == ascii_str
assert upretty(Y) == ucode_str
Z = X[1:10:2]
ascii_str = ucode_str = "X[1:10:2, :n]"
assert pretty(Z) == ascii_str
assert upretty(Z) == ucode_str
def test_pretty_dotproduct():
from sympy.matrices import Matrix, MatrixSymbol
from sympy.matrices.expressions.dotproduct import DotProduct
n = symbols("n", integer=True)
A = MatrixSymbol('A', n, 1)
B = MatrixSymbol('B', n, 1)
C = Matrix(1, 3, [1, 2, 3])
D = Matrix(1, 3, [1, 3, 4])
assert pretty(DotProduct(A, B)) == u"A*B"
assert pretty(DotProduct(C, D)) == u"[1 2 3]*[1 3 4]"
assert upretty(DotProduct(A, B)) == u"A⋅B"
assert upretty(DotProduct(C, D)) == u"[1 2 3]⋅[1 3 4]"
def test_pretty_piecewise():
expr = Piecewise((x, x < 1), (x**2, True))
ascii_str = \
"""\
/x for x < 1\n\
| \n\
< 2 \n\
|x otherwise\n\
\\ \
"""
ucode_str = \
u("""\
⎧x for x < 1\n\
⎪ \n\
⎨ 2 \n\
⎪x otherwise\n\
⎩ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -Piecewise((x, x < 1), (x**2, True))
ascii_str = \
"""\
//x for x < 1\\\n\
|| |\n\
-|< 2 |\n\
||x otherwise|\n\
\\\\ /\
"""
ucode_str = \
u("""\
⎛⎧x for x < 1⎞\n\
⎜⎪ ⎟\n\
-⎜⎨ 2 ⎟\n\
⎜⎪x otherwise⎟\n\
⎝⎩ ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = x + Piecewise((x, x > 0), (y, True)) + Piecewise((x/y, x < 2),
(y**2, x > 2), (1, True)) + 1
ascii_str = \
"""\
//x \\ \n\
||- for x < 2| \n\
||y | \n\
//x for x > 0\\ || | \n\
x + |< | + |< 2 | + 1\n\
\\\\y otherwise/ ||y for x > 2| \n\
|| | \n\
||1 otherwise| \n\
\\\\ / \
"""
ucode_str = \
u("""\
⎛⎧x ⎞ \n\
⎜⎪─ for x < 2⎟ \n\
⎜⎪y ⎟ \n\
⎛⎧x for x > 0⎞ ⎜⎪ ⎟ \n\
x + ⎜⎨ ⎟ + ⎜⎨ 2 ⎟ + 1\n\
⎝⎩y otherwise⎠ ⎜⎪y for x > 2⎟ \n\
⎜⎪ ⎟ \n\
⎜⎪1 otherwise⎟ \n\
⎝⎩ ⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = x - Piecewise((x, x > 0), (y, True)) + Piecewise((x/y, x < 2),
(y**2, x > 2), (1, True)) + 1
ascii_str = \
"""\
//x \\ \n\
||- for x < 2| \n\
||y | \n\
//x for x > 0\\ || | \n\
x - |< | + |< 2 | + 1\n\
\\\\y otherwise/ ||y for x > 2| \n\
|| | \n\
||1 otherwise| \n\
\\\\ / \
"""
ucode_str = \
u("""\
⎛⎧x ⎞ \n\
⎜⎪─ for x < 2⎟ \n\
⎜⎪y ⎟ \n\
⎛⎧x for x > 0⎞ ⎜⎪ ⎟ \n\
x - ⎜⎨ ⎟ + ⎜⎨ 2 ⎟ + 1\n\
⎝⎩y otherwise⎠ ⎜⎪y for x > 2⎟ \n\
⎜⎪ ⎟ \n\
⎜⎪1 otherwise⎟ \n\
⎝⎩ ⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = x*Piecewise((x, x > 0), (y, True))
ascii_str = \
"""\
//x for x > 0\\\n\
x*|< |\n\
\\\\y otherwise/\
"""
ucode_str = \
u("""\
⎛⎧x for x > 0⎞\n\
x⋅⎜⎨ ⎟\n\
⎝⎩y otherwise⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Piecewise((x, x > 0), (y, True))*Piecewise((x/y, x < 2), (y**2, x >
2), (1, True))
ascii_str = \
"""\
//x \\\n\
||- for x < 2|\n\
||y |\n\
//x for x > 0\\ || |\n\
|< |*|< 2 |\n\
\\\\y otherwise/ ||y for x > 2|\n\
|| |\n\
||1 otherwise|\n\
\\\\ /\
"""
ucode_str = \
u("""\
⎛⎧x ⎞\n\
⎜⎪─ for x < 2⎟\n\
⎜⎪y ⎟\n\
⎛⎧x for x > 0⎞ ⎜⎪ ⎟\n\
⎜⎨ ⎟⋅⎜⎨ 2 ⎟\n\
⎝⎩y otherwise⎠ ⎜⎪y for x > 2⎟\n\
⎜⎪ ⎟\n\
⎜⎪1 otherwise⎟\n\
⎝⎩ ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -Piecewise((x, x > 0), (y, True))*Piecewise((x/y, x < 2), (y**2, x
> 2), (1, True))
ascii_str = \
"""\
//x \\\n\
||- for x < 2|\n\
||y |\n\
//x for x > 0\\ || |\n\
-|< |*|< 2 |\n\
\\\\y otherwise/ ||y for x > 2|\n\
|| |\n\
||1 otherwise|\n\
\\\\ /\
"""
ucode_str = \
u("""\
⎛⎧x ⎞\n\
⎜⎪─ for x < 2⎟\n\
⎜⎪y ⎟\n\
⎛⎧x for x > 0⎞ ⎜⎪ ⎟\n\
-⎜⎨ ⎟⋅⎜⎨ 2 ⎟\n\
⎝⎩y otherwise⎠ ⎜⎪y for x > 2⎟\n\
⎜⎪ ⎟\n\
⎜⎪1 otherwise⎟\n\
⎝⎩ ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Piecewise((0, Abs(1/y) < 1), (1, Abs(y) < 1), (y*meijerg(((2, 1),
()), ((), (1, 0)), 1/y), True))
ascii_str = \
"""\
/ |1| \n\
| 0 for |-| < 1\n\
| |y| \n\
| \n\
< 1 for |y| < 1\n\
| \n\
| __0, 2 /2, 1 | 1\\ \n\
|y*/__ | | -| otherwise \n\
\\ \\_|2, 2 \\ 1, 0 | y/ \
"""
ucode_str = \
u("""\
⎧ │1│ \n\
⎪ 0 for │─│ < 1\n\
⎪ │y│ \n\
⎪ \n\
⎨ 1 for │y│ < 1\n\
⎪ \n\
⎪ ╭─╮0, 2 ⎛2, 1 │ 1⎞ \n\
⎪y⋅│╶┐ ⎜ │ ─⎟ otherwise \n\
⎩ ╰─╯2, 2 ⎝ 1, 0 │ y⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
# XXX: We have to use evaluate=False here because Piecewise._eval_power
# denests the power.
expr = Pow(Piecewise((x, x > 0), (y, True)), 2, evaluate=False)
ascii_str = \
"""\
2\n\
//x for x > 0\\ \n\
|< | \n\
\\\\y otherwise/ \
"""
ucode_str = \
u("""\
2\n\
⎛⎧x for x > 0⎞ \n\
⎜⎨ ⎟ \n\
⎝⎩y otherwise⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_ITE():
expr = ITE(x, y, z)
assert pretty(expr) == (
'/y for x \n'
'< \n'
'\\z otherwise'
)
assert upretty(expr) == u("""\
⎧y for x \n\
⎨ \n\
⎩z otherwise\
""")
def test_pretty_seq():
expr = ()
ascii_str = \
"""\
()\
"""
ucode_str = \
u("""\
()\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = []
ascii_str = \
"""\
[]\
"""
ucode_str = \
u("""\
[]\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = {}
expr_2 = {}
ascii_str = \
"""\
{}\
"""
ucode_str = \
u("""\
{}\
""")
assert pretty(expr) == ascii_str
assert pretty(expr_2) == ascii_str
assert upretty(expr) == ucode_str
assert upretty(expr_2) == ucode_str
expr = (1/x,)
ascii_str = \
"""\
1 \n\
(-,)\n\
x \
"""
ucode_str = \
u("""\
⎛1 ⎞\n\
⎜─,⎟\n\
⎝x ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = [x**2, 1/x, x, y, sin(th)**2/cos(ph)**2]
ascii_str = \
"""\
2 \n\
2 1 sin (theta) \n\
[x , -, x, y, -----------]\n\
x 2 \n\
cos (phi) \
"""
ucode_str = \
u("""\
⎡ 2 ⎤\n\
⎢ 2 1 sin (θ)⎥\n\
⎢x , ─, x, y, ───────⎥\n\
⎢ x 2 ⎥\n\
⎣ cos (φ)⎦\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (x**2, 1/x, x, y, sin(th)**2/cos(ph)**2)
ascii_str = \
"""\
2 \n\
2 1 sin (theta) \n\
(x , -, x, y, -----------)\n\
x 2 \n\
cos (phi) \
"""
ucode_str = \
u("""\
⎛ 2 ⎞\n\
⎜ 2 1 sin (θ)⎟\n\
⎜x , ─, x, y, ───────⎟\n\
⎜ x 2 ⎟\n\
⎝ cos (φ)⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Tuple(x**2, 1/x, x, y, sin(th)**2/cos(ph)**2)
ascii_str = \
"""\
2 \n\
2 1 sin (theta) \n\
(x , -, x, y, -----------)\n\
x 2 \n\
cos (phi) \
"""
ucode_str = \
u("""\
⎛ 2 ⎞\n\
⎜ 2 1 sin (θ)⎟\n\
⎜x , ─, x, y, ───────⎟\n\
⎜ x 2 ⎟\n\
⎝ cos (φ)⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = {x: sin(x)}
expr_2 = Dict({x: sin(x)})
ascii_str = \
"""\
{x: sin(x)}\
"""
ucode_str = \
u("""\
{x: sin(x)}\
""")
assert pretty(expr) == ascii_str
assert pretty(expr_2) == ascii_str
assert upretty(expr) == ucode_str
assert upretty(expr_2) == ucode_str
expr = {1/x: 1/y, x: sin(x)**2}
expr_2 = Dict({1/x: 1/y, x: sin(x)**2})
ascii_str = \
"""\
1 1 2 \n\
{-: -, x: sin (x)}\n\
x y \
"""
ucode_str = \
u("""\
⎧1 1 2 ⎫\n\
⎨─: ─, x: sin (x)⎬\n\
⎩x y ⎭\
""")
assert pretty(expr) == ascii_str
assert pretty(expr_2) == ascii_str
assert upretty(expr) == ucode_str
assert upretty(expr_2) == ucode_str
# There used to be a bug with pretty-printing sequences of even height.
expr = [x**2]
ascii_str = \
"""\
2 \n\
[x ]\
"""
ucode_str = \
u("""\
⎡ 2⎤\n\
⎣x ⎦\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (x**2,)
ascii_str = \
"""\
2 \n\
(x ,)\
"""
ucode_str = \
u("""\
⎛ 2 ⎞\n\
⎝x ,⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Tuple(x**2)
ascii_str = \
"""\
2 \n\
(x ,)\
"""
ucode_str = \
u("""\
⎛ 2 ⎞\n\
⎝x ,⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = {x**2: 1}
expr_2 = Dict({x**2: 1})
ascii_str = \
"""\
2 \n\
{x : 1}\
"""
ucode_str = \
u("""\
⎧ 2 ⎫\n\
⎨x : 1⎬\n\
⎩ ⎭\
""")
assert pretty(expr) == ascii_str
assert pretty(expr_2) == ascii_str
assert upretty(expr) == ucode_str
assert upretty(expr_2) == ucode_str
def test_any_object_in_sequence():
# Cf. issue 5306
b1 = Basic()
b2 = Basic(Basic())
expr = [b2, b1]
assert pretty(expr) == "[Basic(Basic()), Basic()]"
assert upretty(expr) == u"[Basic(Basic()), Basic()]"
expr = {b2, b1}
assert pretty(expr) == "{Basic(), Basic(Basic())}"
assert upretty(expr) == u"{Basic(), Basic(Basic())}"
expr = {b2: b1, b1: b2}
expr2 = Dict({b2: b1, b1: b2})
assert pretty(expr) == "{Basic(): Basic(Basic()), Basic(Basic()): Basic()}"
assert pretty(
expr2) == "{Basic(): Basic(Basic()), Basic(Basic()): Basic()}"
assert upretty(
expr) == u"{Basic(): Basic(Basic()), Basic(Basic()): Basic()}"
assert upretty(
expr2) == u"{Basic(): Basic(Basic()), Basic(Basic()): Basic()}"
def test_print_builtin_set():
assert pretty(set()) == 'set()'
assert upretty(set()) == u'set()'
assert pretty(frozenset()) == 'frozenset()'
assert upretty(frozenset()) == u'frozenset()'
s1 = {1/x, x}
s2 = frozenset(s1)
assert pretty(s1) == \
"""\
1 \n\
{-, x}
x \
"""
assert upretty(s1) == \
u"""\
⎧1 ⎫
⎨─, x⎬
⎩x ⎭\
"""
assert pretty(s2) == \
"""\
1 \n\
frozenset({-, x})
x \
"""
assert upretty(s2) == \
u"""\
⎛⎧1 ⎫⎞
frozenset⎜⎨─, x⎬⎟
⎝⎩x ⎭⎠\
"""
def test_pretty_sets():
s = FiniteSet
assert pretty(s(*[x*y, x**2])) == \
"""\
2 \n\
{x , x*y}\
"""
assert pretty(s(*range(1, 6))) == "{1, 2, 3, 4, 5}"
assert pretty(s(*range(1, 13))) == "{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}"
assert pretty(set([x*y, x**2])) == \
"""\
2 \n\
{x , x*y}\
"""
assert pretty(set(range(1, 6))) == "{1, 2, 3, 4, 5}"
assert pretty(set(range(1, 13))) == \
"{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}"
assert pretty(frozenset([x*y, x**2])) == \
"""\
2 \n\
frozenset({x , x*y})\
"""
assert pretty(frozenset(range(1, 6))) == "frozenset({1, 2, 3, 4, 5})"
assert pretty(frozenset(range(1, 13))) == \
"frozenset({1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12})"
assert pretty(Range(0, 3, 1)) == '{0, 1, 2}'
ascii_str = '{0, 1, ..., 29}'
ucode_str = u'{0, 1, …, 29}'
assert pretty(Range(0, 30, 1)) == ascii_str
assert upretty(Range(0, 30, 1)) == ucode_str
ascii_str = '{30, 29, ..., 2}'
ucode_str = u('{30, 29, …, 2}')
assert pretty(Range(30, 1, -1)) == ascii_str
assert upretty(Range(30, 1, -1)) == ucode_str
ascii_str = '{0, 2, ..., oo}'
ucode_str = u'{0, 2, …, ∞}'
assert pretty(Range(0, oo, 2)) == ascii_str
assert upretty(Range(0, oo, 2)) == ucode_str
ascii_str = '{oo, ..., 2, 0}'
ucode_str = u('{∞, …, 2, 0}')
assert pretty(Range(oo, -2, -2)) == ascii_str
assert upretty(Range(oo, -2, -2)) == ucode_str
ascii_str = '{-2, -3, ..., -oo}'
ucode_str = u('{-2, -3, …, -∞}')
assert pretty(Range(-2, -oo, -1)) == ascii_str
assert upretty(Range(-2, -oo, -1)) == ucode_str
def test_pretty_SetExpr():
iv = Interval(1, 3)
se = SetExpr(iv)
ascii_str = "SetExpr([1, 3])"
ucode_str = u("SetExpr([1, 3])")
assert pretty(se) == ascii_str
assert upretty(se) == ucode_str
def test_pretty_ImageSet():
imgset = ImageSet(Lambda((x, y), x + y), {1, 2, 3}, {3, 4})
ascii_str = '{x + y | x in {1, 2, 3} , y in {3, 4}}'
ucode_str = u('{x + y | x ∊ {1, 2, 3} , y ∊ {3, 4}}')
assert pretty(imgset) == ascii_str
assert upretty(imgset) == ucode_str
imgset = ImageSet(Lambda(x, x**2), S.Naturals)
ascii_str = \
' 2 \n'\
'{x | x in Naturals}'
ucode_str = u('''\
⎧ 2 ⎫\n\
⎨x | x ∊ ℕ⎬\n\
⎩ ⎭''')
assert pretty(imgset) == ascii_str
assert upretty(imgset) == ucode_str
def test_pretty_ConditionSet():
from sympy import ConditionSet
ascii_str = '{x | x in (-oo, oo) and sin(x) = 0}'
ucode_str = u'{x | x ∊ ℝ ∧ sin(x) = 0}'
assert pretty(ConditionSet(x, Eq(sin(x), 0), S.Reals)) == ascii_str
assert upretty(ConditionSet(x, Eq(sin(x), 0), S.Reals)) == ucode_str
assert pretty(ConditionSet(x, Contains(x, S.Reals, evaluate=False), FiniteSet(1))) == '{1}'
assert upretty(ConditionSet(x, Contains(x, S.Reals, evaluate=False), FiniteSet(1))) == u'{1}'
assert pretty(ConditionSet(x, And(x > 1, x < -1), FiniteSet(1, 2, 3))) == "EmptySet()"
assert upretty(ConditionSet(x, And(x > 1, x < -1), FiniteSet(1, 2, 3))) == u"∅"
assert pretty(ConditionSet(x, Or(x > 1, x < -1), FiniteSet(1, 2))) == '{2}'
assert upretty(ConditionSet(x, Or(x > 1, x < -1), FiniteSet(1, 2))) == u'{2}'
def test_pretty_ComplexRegion():
from sympy import ComplexRegion
ucode_str = u'{x + y⋅ⅈ | x, y ∊ [3, 5] × [4, 6]}'
assert upretty(ComplexRegion(Interval(3, 5)*Interval(4, 6))) == ucode_str
ucode_str = u'{r⋅(ⅈ⋅sin(θ) + cos(θ)) | r, θ ∊ [0, 1] × [0, 2⋅π)}'
assert upretty(ComplexRegion(Interval(0, 1)*Interval(0, 2*pi), polar=True)) == ucode_str
def test_pretty_Union_issue_10414():
a, b = Interval(2, 3), Interval(4, 7)
ucode_str = u'[2, 3] ∪ [4, 7]'
ascii_str = '[2, 3] U [4, 7]'
assert upretty(Union(a, b)) == ucode_str
assert pretty(Union(a, b)) == ascii_str
def test_pretty_Intersection_issue_10414():
x, y, z, w = symbols('x, y, z, w')
a, b = Interval(x, y), Interval(z, w)
ucode_str = u'[x, y] ∩ [z, w]'
ascii_str = '[x, y] n [z, w]'
assert upretty(Intersection(a, b)) == ucode_str
assert pretty(Intersection(a, b)) == ascii_str
def test_ProductSet_paranthesis():
ucode_str = u'([4, 7] × {1, 2}) ∪ ([2, 3] × [4, 7])'
a, b, c = Interval(2, 3), Interval(4, 7), Interval(1, 9)
assert upretty(Union(a*b, b*FiniteSet(1, 2))) == ucode_str
def test_ProductSet_prod_char_issue_10413():
ascii_str = '[2, 3] x [4, 7]'
ucode_str = u'[2, 3] × [4, 7]'
a, b = Interval(2, 3), Interval(4, 7)
assert pretty(a*b) == ascii_str
assert upretty(a*b) == ucode_str
def test_pretty_sequences():
s1 = SeqFormula(a**2, (0, oo))
s2 = SeqPer((1, 2))
ascii_str = '[0, 1, 4, 9, ...]'
ucode_str = u'[0, 1, 4, 9, …]'
assert pretty(s1) == ascii_str
assert upretty(s1) == ucode_str
ascii_str = '[1, 2, 1, 2, ...]'
ucode_str = u'[1, 2, 1, 2, …]'
assert pretty(s2) == ascii_str
assert upretty(s2) == ucode_str
s3 = SeqFormula(a**2, (0, 2))
s4 = SeqPer((1, 2), (0, 2))
ascii_str = '[0, 1, 4]'
ucode_str = u'[0, 1, 4]'
assert pretty(s3) == ascii_str
assert upretty(s3) == ucode_str
ascii_str = '[1, 2, 1]'
ucode_str = u'[1, 2, 1]'
assert pretty(s4) == ascii_str
assert upretty(s4) == ucode_str
s5 = SeqFormula(a**2, (-oo, 0))
s6 = SeqPer((1, 2), (-oo, 0))
ascii_str = '[..., 9, 4, 1, 0]'
ucode_str = u'[…, 9, 4, 1, 0]'
assert pretty(s5) == ascii_str
assert upretty(s5) == ucode_str
ascii_str = '[..., 2, 1, 2, 1]'
ucode_str = u'[…, 2, 1, 2, 1]'
assert pretty(s6) == ascii_str
assert upretty(s6) == ucode_str
ascii_str = '[1, 3, 5, 11, ...]'
ucode_str = u'[1, 3, 5, 11, …]'
assert pretty(SeqAdd(s1, s2)) == ascii_str
assert upretty(SeqAdd(s1, s2)) == ucode_str
ascii_str = '[1, 3, 5]'
ucode_str = u'[1, 3, 5]'
assert pretty(SeqAdd(s3, s4)) == ascii_str
assert upretty(SeqAdd(s3, s4)) == ucode_str
ascii_str = '[..., 11, 5, 3, 1]'
ucode_str = u'[…, 11, 5, 3, 1]'
assert pretty(SeqAdd(s5, s6)) == ascii_str
assert upretty(SeqAdd(s5, s6)) == ucode_str
ascii_str = '[0, 2, 4, 18, ...]'
ucode_str = u'[0, 2, 4, 18, …]'
assert pretty(SeqMul(s1, s2)) == ascii_str
assert upretty(SeqMul(s1, s2)) == ucode_str
ascii_str = '[0, 2, 4]'
ucode_str = u'[0, 2, 4]'
assert pretty(SeqMul(s3, s4)) == ascii_str
assert upretty(SeqMul(s3, s4)) == ucode_str
ascii_str = '[..., 18, 4, 2, 0]'
ucode_str = u'[…, 18, 4, 2, 0]'
assert pretty(SeqMul(s5, s6)) == ascii_str
assert upretty(SeqMul(s5, s6)) == ucode_str
def test_pretty_FourierSeries():
f = fourier_series(x, (x, -pi, pi))
ascii_str = \
"""\
2*sin(3*x) \n\
2*sin(x) - sin(2*x) + ---------- + ...\n\
3 \
"""
ucode_str = \
u("""\
2⋅sin(3⋅x) \n\
2⋅sin(x) - sin(2⋅x) + ────────── + …\n\
3 \
""")
assert pretty(f) == ascii_str
assert upretty(f) == ucode_str
def test_pretty_FormalPowerSeries():
f = fps(log(1 + x))
ascii_str = \
"""\
oo \n\
____ \n\
\\ ` \n\
\\ -k k \n\
\\ -(-1) *x \n\
/ -----------\n\
/ k \n\
/___, \n\
k = 1 \
"""
ucode_str = \
u("""\
∞ \n\
____ \n\
╲ \n\
╲ -k k \n\
╲ -(-1) ⋅x \n\
╱ ───────────\n\
╱ k \n\
╱ \n\
‾‾‾‾ \n\
k = 1 \
""")
assert pretty(f) == ascii_str
assert upretty(f) == ucode_str
def test_pretty_limits():
expr = Limit(x, x, oo)
ascii_str = \
"""\
lim x\n\
x->oo \
"""
ucode_str = \
u("""\
lim x\n\
x─→∞ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(x**2, x, 0)
ascii_str = \
"""\
2\n\
lim x \n\
x->0+ \
"""
ucode_str = \
u("""\
2\n\
lim x \n\
x─→0⁺ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(1/x, x, 0)
ascii_str = \
"""\
1\n\
lim -\n\
x->0+x\
"""
ucode_str = \
u("""\
1\n\
lim ─\n\
x─→0⁺x\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(sin(x)/x, x, 0)
ascii_str = \
"""\
/sin(x)\\\n\
lim |------|\n\
x->0+\\ x /\
"""
ucode_str = \
u("""\
⎛sin(x)⎞\n\
lim ⎜──────⎟\n\
x─→0⁺⎝ x ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(sin(x)/x, x, 0, "-")
ascii_str = \
"""\
/sin(x)\\\n\
lim |------|\n\
x->0-\\ x /\
"""
ucode_str = \
u("""\
⎛sin(x)⎞\n\
lim ⎜──────⎟\n\
x─→0⁻⎝ x ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(x + sin(x), x, 0)
ascii_str = \
"""\
lim (x + sin(x))\n\
x->0+ \
"""
ucode_str = \
u("""\
lim (x + sin(x))\n\
x─→0⁺ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(x, x, 0)**2
ascii_str = \
"""\
2\n\
/ lim x\\ \n\
\\x->0+ / \
"""
ucode_str = \
u("""\
2\n\
⎛ lim x⎞ \n\
⎝x─→0⁺ ⎠ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(x*Limit(y/2,y,0), x, 0)
ascii_str = \
"""\
/ /y\\\\\n\
lim |x* lim |-||\n\
x->0+\\ y->0+\\2//\
"""
ucode_str = \
u("""\
⎛ ⎛y⎞⎞\n\
lim ⎜x⋅ lim ⎜─⎟⎟\n\
x─→0⁺⎝ y─→0⁺⎝2⎠⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = 2*Limit(x*Limit(y/2,y,0), x, 0)
ascii_str = \
"""\
/ /y\\\\\n\
2* lim |x* lim |-||\n\
x->0+\\ y->0+\\2//\
"""
ucode_str = \
u("""\
⎛ ⎛y⎞⎞\n\
2⋅ lim ⎜x⋅ lim ⎜─⎟⎟\n\
x─→0⁺⎝ y─→0⁺⎝2⎠⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Limit(sin(x), x, 0, dir='+-')
ascii_str = \
"""\
lim sin(x)\n\
x->0 \
"""
ucode_str = \
u("""\
lim sin(x)\n\
x─→0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_ComplexRootOf():
expr = rootof(x**5 + 11*x - 2, 0)
ascii_str = \
"""\
/ 5 \\\n\
CRootOf\\x + 11*x - 2, 0/\
"""
ucode_str = \
u("""\
⎛ 5 ⎞\n\
CRootOf⎝x + 11⋅x - 2, 0⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_RootSum():
expr = RootSum(x**5 + 11*x - 2, auto=False)
ascii_str = \
"""\
/ 5 \\\n\
RootSum\\x + 11*x - 2/\
"""
ucode_str = \
u("""\
⎛ 5 ⎞\n\
RootSum⎝x + 11⋅x - 2⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = RootSum(x**5 + 11*x - 2, Lambda(z, exp(z)))
ascii_str = \
"""\
/ 5 z\\\n\
RootSum\\x + 11*x - 2, z -> e /\
"""
ucode_str = \
u("""\
⎛ 5 z⎞\n\
RootSum⎝x + 11⋅x - 2, z ↦ ℯ ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_GroebnerBasis():
expr = groebner([], x, y)
ascii_str = \
"""\
GroebnerBasis([], x, y, domain=ZZ, order=lex)\
"""
ucode_str = \
u("""\
GroebnerBasis([], x, y, domain=ℤ, order=lex)\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
F = [x**2 - 3*y - x + 1, y**2 - 2*x + y - 1]
expr = groebner(F, x, y, order='grlex')
ascii_str = \
"""\
/[ 2 2 ] \\\n\
GroebnerBasis\\[x - x - 3*y + 1, y - 2*x + y - 1], x, y, domain=ZZ, order=grlex/\
"""
ucode_str = \
u("""\
⎛⎡ 2 2 ⎤ ⎞\n\
GroebnerBasis⎝⎣x - x - 3⋅y + 1, y - 2⋅x + y - 1⎦, x, y, domain=ℤ, order=grlex⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = expr.fglm('lex')
ascii_str = \
"""\
/[ 2 4 3 2 ] \\\n\
GroebnerBasis\\[2*x - y - y + 1, y + 2*y - 3*y - 16*y + 7], x, y, domain=ZZ, order=lex/\
"""
ucode_str = \
u("""\
⎛⎡ 2 4 3 2 ⎤ ⎞\n\
GroebnerBasis⎝⎣2⋅x - y - y + 1, y + 2⋅y - 3⋅y - 16⋅y + 7⎦, x, y, domain=ℤ, order=lex⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_Boolean():
expr = Not(x, evaluate=False)
assert pretty(expr) == "Not(x)"
assert upretty(expr) == u"¬x"
expr = And(x, y)
assert pretty(expr) == "And(x, y)"
assert upretty(expr) == u"x ∧ y"
expr = Or(x, y)
assert pretty(expr) == "Or(x, y)"
assert upretty(expr) == u"x ∨ y"
syms = symbols('a:f')
expr = And(*syms)
assert pretty(expr) == "And(a, b, c, d, e, f)"
assert upretty(expr) == u"a ∧ b ∧ c ∧ d ∧ e ∧ f"
expr = Or(*syms)
assert pretty(expr) == "Or(a, b, c, d, e, f)"
assert upretty(expr) == u"a ∨ b ∨ c ∨ d ∨ e ∨ f"
expr = Xor(x, y, evaluate=False)
assert pretty(expr) == "Xor(x, y)"
assert upretty(expr) == u"x ⊻ y"
expr = Nand(x, y, evaluate=False)
assert pretty(expr) == "Nand(x, y)"
assert upretty(expr) == u"x ⊼ y"
expr = Nor(x, y, evaluate=False)
assert pretty(expr) == "Nor(x, y)"
assert upretty(expr) == u"x ⊽ y"
expr = Implies(x, y, evaluate=False)
assert pretty(expr) == "Implies(x, y)"
assert upretty(expr) == u"x → y"
# don't sort args
expr = Implies(y, x, evaluate=False)
assert pretty(expr) == "Implies(y, x)"
assert upretty(expr) == u"y → x"
expr = Equivalent(x, y, evaluate=False)
assert pretty(expr) == "Equivalent(x, y)"
assert upretty(expr) == u"x ⇔ y"
expr = Equivalent(y, x, evaluate=False)
assert pretty(expr) == "Equivalent(x, y)"
assert upretty(expr) == u"x ⇔ y"
def test_pretty_Domain():
expr = FF(23)
assert pretty(expr) == "GF(23)"
assert upretty(expr) == u"ℤ₂₃"
expr = ZZ
assert pretty(expr) == "ZZ"
assert upretty(expr) == u"ℤ"
expr = QQ
assert pretty(expr) == "QQ"
assert upretty(expr) == u"ℚ"
expr = RR
assert pretty(expr) == "RR"
assert upretty(expr) == u"ℝ"
expr = QQ[x]
assert pretty(expr) == "QQ[x]"
assert upretty(expr) == u"ℚ[x]"
expr = QQ[x, y]
assert pretty(expr) == "QQ[x, y]"
assert upretty(expr) == u"ℚ[x, y]"
expr = ZZ.frac_field(x)
assert pretty(expr) == "ZZ(x)"
assert upretty(expr) == u"ℤ(x)"
expr = ZZ.frac_field(x, y)
assert pretty(expr) == "ZZ(x, y)"
assert upretty(expr) == u"ℤ(x, y)"
expr = QQ.poly_ring(x, y, order=grlex)
assert pretty(expr) == "QQ[x, y, order=grlex]"
assert upretty(expr) == u"ℚ[x, y, order=grlex]"
expr = QQ.poly_ring(x, y, order=ilex)
assert pretty(expr) == "QQ[x, y, order=ilex]"
assert upretty(expr) == u"ℚ[x, y, order=ilex]"
def test_pretty_prec():
assert xpretty(S("0.3"), full_prec=True, wrap_line=False) == "0.300000000000000"
assert xpretty(S("0.3"), full_prec="auto", wrap_line=False) == "0.300000000000000"
assert xpretty(S("0.3"), full_prec=False, wrap_line=False) == "0.3"
assert xpretty(S("0.3")*x, full_prec=True, use_unicode=False, wrap_line=False) in [
"0.300000000000000*x",
"x*0.300000000000000"
]
assert xpretty(S("0.3")*x, full_prec="auto", use_unicode=False, wrap_line=False) in [
"0.3*x",
"x*0.3"
]
assert xpretty(S("0.3")*x, full_prec=False, use_unicode=False, wrap_line=False) in [
"0.3*x",
"x*0.3"
]
def test_pprint():
import sys
from sympy.core.compatibility import StringIO
fd = StringIO()
sso = sys.stdout
sys.stdout = fd
try:
pprint(pi, use_unicode=False, wrap_line=False)
finally:
sys.stdout = sso
assert fd.getvalue() == 'pi\n'
def test_pretty_class():
"""Test that the printer dispatcher correctly handles classes."""
class C:
pass # C has no .__class__ and this was causing problems
class D(object):
pass
assert pretty( C ) == str( C )
assert pretty( D ) == str( D )
def test_pretty_no_wrap_line():
huge_expr = 0
for i in range(20):
huge_expr += i*sin(i + x)
assert xpretty(huge_expr ).find('\n') != -1
assert xpretty(huge_expr, wrap_line=False).find('\n') == -1
def test_settings():
raises(TypeError, lambda: pretty(S(4), method="garbage"))
def test_pretty_sum():
from sympy.abc import x, a, b, k, m, n
expr = Sum(k**k, (k, 0, n))
ascii_str = \
"""\
n \n\
___ \n\
\\ ` \n\
\\ k\n\
/ k \n\
/__, \n\
k = 0 \
"""
ucode_str = \
u("""\
n \n\
___ \n\
╲ \n\
╲ k\n\
╱ k \n\
╱ \n\
‾‾‾ \n\
k = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(k**k, (k, oo, n))
ascii_str = \
"""\
n \n\
___ \n\
\\ ` \n\
\\ k\n\
/ k \n\
/__, \n\
k = oo \
"""
ucode_str = \
u("""\
n \n\
___ \n\
╲ \n\
╲ k\n\
╱ k \n\
╱ \n\
‾‾‾ \n\
k = ∞ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(k**(Integral(x**n, (x, -oo, oo))), (k, 0, n**n))
ascii_str = \
"""\
n \n\
n \n\
______ \n\
\\ ` \n\
\\ oo \n\
\\ / \n\
\\ | \n\
\\ | n \n\
) | x dx\n\
/ | \n\
/ / \n\
/ -oo \n\
/ k \n\
/_____, \n\
k = 0 \
"""
ucode_str = \
u("""\
n \n\
n \n\
______ \n\
╲ \n\
╲ ∞ \n\
╲ ⌠ \n\
╲ ⎮ n \n\
╲ ⎮ x dx\n\
╱ ⌡ \n\
╱ -∞ \n\
╱ k \n\
╱ \n\
╱ \n\
‾‾‾‾‾‾ \n\
k = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(k**(
Integral(x**n, (x, -oo, oo))), (k, 0, Integral(x**x, (x, -oo, oo))))
ascii_str = \
"""\
oo \n\
/ \n\
| \n\
| x \n\
| x dx \n\
| \n\
/ \n\
-oo \n\
______ \n\
\\ ` \n\
\\ oo \n\
\\ / \n\
\\ | \n\
\\ | n \n\
) | x dx\n\
/ | \n\
/ / \n\
/ -oo \n\
/ k \n\
/_____, \n\
k = 0 \
"""
ucode_str = \
u("""\
∞ \n\
⌠ \n\
⎮ x \n\
⎮ x dx \n\
⌡ \n\
-∞ \n\
______ \n\
╲ \n\
╲ ∞ \n\
╲ ⌠ \n\
╲ ⎮ n \n\
╲ ⎮ x dx\n\
╱ ⌡ \n\
╱ -∞ \n\
╱ k \n\
╱ \n\
╱ \n\
‾‾‾‾‾‾ \n\
k = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(k**(Integral(x**n, (x, -oo, oo))), (
k, x + n + x**2 + n**2 + (x/n) + (1/x), Integral(x**x, (x, -oo, oo))))
ascii_str = \
"""\
oo \n\
/ \n\
| \n\
| x \n\
| x dx \n\
| \n\
/ \n\
-oo \n\
______ \n\
\\ ` \n\
\\ oo \n\
\\ / \n\
\\ | \n\
\\ | n \n\
) | x dx\n\
/ | \n\
/ / \n\
/ -oo \n\
/ k \n\
/_____, \n\
2 2 1 x \n\
k = n + n + x + x + - + - \n\
x n \
"""
ucode_str = \
u("""\
∞ \n\
⌠ \n\
⎮ x \n\
⎮ x dx \n\
⌡ \n\
-∞ \n\
______ \n\
╲ \n\
╲ ∞ \n\
╲ ⌠ \n\
╲ ⎮ n \n\
╲ ⎮ x dx\n\
╱ ⌡ \n\
╱ -∞ \n\
╱ k \n\
╱ \n\
╱ \n\
‾‾‾‾‾‾ \n\
2 2 1 x \n\
k = n + n + x + x + ─ + ─ \n\
x n \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(k**(
Integral(x**n, (x, -oo, oo))), (k, 0, x + n + x**2 + n**2 + (x/n) + (1/x)))
ascii_str = \
"""\
2 2 1 x \n\
n + n + x + x + - + - \n\
x n \n\
______ \n\
\\ ` \n\
\\ oo \n\
\\ / \n\
\\ | \n\
\\ | n \n\
) | x dx\n\
/ | \n\
/ / \n\
/ -oo \n\
/ k \n\
/_____, \n\
k = 0 \
"""
ucode_str = \
u("""\
2 2 1 x \n\
n + n + x + x + ─ + ─ \n\
x n \n\
______ \n\
╲ \n\
╲ ∞ \n\
╲ ⌠ \n\
╲ ⎮ n \n\
╲ ⎮ x dx\n\
╱ ⌡ \n\
╱ -∞ \n\
╱ k \n\
╱ \n\
╱ \n\
‾‾‾‾‾‾ \n\
k = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(x, (x, 0, oo))
ascii_str = \
"""\
oo \n\
__ \n\
\\ ` \n\
) x\n\
/_, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
___ \n\
╲ \n\
╲ x\n\
╱ \n\
╱ \n\
‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(x**2, (x, 0, oo))
ascii_str = \
u("""\
oo \n\
___ \n\
\\ ` \n\
\\ 2\n\
/ x \n\
/__, \n\
x = 0 \
""")
ucode_str = \
u("""\
∞ \n\
___ \n\
╲ \n\
╲ 2\n\
╱ x \n\
╱ \n\
‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(x/2, (x, 0, oo))
ascii_str = \
"""\
oo \n\
___ \n\
\\ ` \n\
\\ x\n\
) -\n\
/ 2\n\
/__, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
____ \n\
╲ \n\
╲ x\n\
╲ ─\n\
╱ 2\n\
╱ \n\
╱ \n\
‾‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(x**3/2, (x, 0, oo))
ascii_str = \
"""\
oo \n\
____ \n\
\\ ` \n\
\\ 3\n\
\\ x \n\
/ --\n\
/ 2 \n\
/___, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
____ \n\
╲ \n\
╲ 3\n\
╲ x \n\
╱ ──\n\
╱ 2 \n\
╱ \n\
‾‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum((x**3*y**(x/2))**n, (x, 0, oo))
ascii_str = \
"""\
oo \n\
____ \n\
\\ ` \n\
\\ n\n\
\\ / x\\ \n\
) | -| \n\
/ | 3 2| \n\
/ \\x *y / \n\
/___, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
_____ \n\
╲ \n\
╲ n\n\
╲ ⎛ x⎞ \n\
╲ ⎜ ─⎟ \n\
╱ ⎜ 3 2⎟ \n\
╱ ⎝x ⋅y ⎠ \n\
╱ \n\
╱ \n\
‾‾‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(1/x**2, (x, 0, oo))
ascii_str = \
"""\
oo \n\
____ \n\
\\ ` \n\
\\ 1 \n\
\\ --\n\
/ 2\n\
/ x \n\
/___, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
____ \n\
╲ \n\
╲ 1 \n\
╲ ──\n\
╱ 2\n\
╱ x \n\
╱ \n\
‾‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(1/y**(a/b), (x, 0, oo))
ascii_str = \
"""\
oo \n\
____ \n\
\\ ` \n\
\\ -a \n\
\\ ---\n\
/ b \n\
/ y \n\
/___, \n\
x = 0 \
"""
ucode_str = \
u("""\
∞ \n\
____ \n\
╲ \n\
╲ -a \n\
╲ ───\n\
╱ b \n\
╱ y \n\
╱ \n\
‾‾‾‾ \n\
x = 0 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Sum(1/y**(a/b), (x, 0, oo), (y, 1, 2))
ascii_str = \
"""\
2 oo \n\
____ ____ \n\
\\ ` \\ ` \n\
\\ \\ -a\n\
\\ \\ --\n\
/ / b \n\
/ / y \n\
/___, /___, \n\
y = 1 x = 0 \
"""
ucode_str = \
u("""\
2 ∞ \n\
____ ____ \n\
╲ ╲ \n\
╲ ╲ -a\n\
╲ ╲ ──\n\
╱ ╱ b \n\
╱ ╱ y \n\
╱ ╱ \n\
‾‾‾‾ ‾‾‾‾ \n\
y = 1 x = 0 \
""")
expr = Sum(1/(1 + 1/(
1 + 1/k)) + 1, (k, 111, 1 + 1/n), (k, 1/(1 + m), oo)) + 1/(1 + 1/k)
ascii_str = \
"""\
1 \n\
1 + - \n\
oo n \n\
_____ _____ \n\
\\ ` \\ ` \n\
\\ \\ / 1 \\ \n\
\\ \\ |1 + ---------| \n\
\\ \\ | 1 | 1 \n\
) ) | 1 + -----| + -----\n\
/ / | 1| 1\n\
/ / | 1 + -| 1 + -\n\
/ / \\ k/ k\n\
/____, /____, \n\
1 k = 111 \n\
k = ----- \n\
m + 1 \
"""
ucode_str = \
u("""\
1 \n\
1 + ─ \n\
∞ n \n\
______ ______ \n\
╲ ╲ \n\
╲ ╲ ⎛ 1 ⎞ \n\
╲ ╲ ⎜1 + ─────────⎟ \n\
╲ ╲ ⎜ 1 ⎟ \n\
╲ ╲ ⎜ 1 + ─────⎟ 1 \n\
╱ ╱ ⎜ 1⎟ + ─────\n\
╱ ╱ ⎜ 1 + ─⎟ 1\n\
╱ ╱ ⎝ k⎠ 1 + ─\n\
╱ ╱ k\n\
╱ ╱ \n\
‾‾‾‾‾‾ ‾‾‾‾‾‾ \n\
1 k = 111 \n\
k = ───── \n\
m + 1 \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_units():
expr = joule
ascii_str1 = \
"""\
2\n\
kilogram*meter \n\
---------------\n\
2 \n\
second \
"""
unicode_str1 = \
u("""\
2\n\
kilogram⋅meter \n\
───────────────\n\
2 \n\
second \
""")
ascii_str2 = \
"""\
2\n\
3*x*y*kilogram*meter \n\
---------------------\n\
2 \n\
second \
"""
unicode_str2 = \
u("""\
2\n\
3⋅x⋅y⋅kilogram⋅meter \n\
─────────────────────\n\
2 \n\
second \
""")
from sympy.physics.units import kg, m, s
assert upretty(expr) == u("joule")
assert pretty(expr) == "joule"
assert upretty(expr.convert_to(kg*m**2/s**2)) == unicode_str1
assert pretty(expr.convert_to(kg*m**2/s**2)) == ascii_str1
assert upretty(3*kg*x*m**2*y/s**2) == unicode_str2
assert pretty(3*kg*x*m**2*y/s**2) == ascii_str2
def test_pretty_Subs():
f = Function('f')
expr = Subs(f(x), x, ph**2)
ascii_str = \
"""\
(f(x))| 2\n\
|x=phi \
"""
unicode_str = \
u("""\
(f(x))│ 2\n\
│x=φ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Subs(f(x).diff(x), x, 0)
ascii_str = \
"""\
/d \\| \n\
|--(f(x))|| \n\
\\dx /|x=0\
"""
unicode_str = \
u("""\
⎛d ⎞│ \n\
⎜──(f(x))⎟│ \n\
⎝dx ⎠│x=0\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
expr = Subs(f(x).diff(x)/y, (x, y), (0, Rational(1, 2)))
ascii_str = \
"""\
/d \\| \n\
|--(f(x))|| \n\
|dx || \n\
|--------|| \n\
\\ y /|x=0, y=1/2\
"""
unicode_str = \
u("""\
⎛d ⎞│ \n\
⎜──(f(x))⎟│ \n\
⎜dx ⎟│ \n\
⎜────────⎟│ \n\
⎝ y ⎠│x=0, y=1/2\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == unicode_str
def test_gammas():
assert upretty(lowergamma(x, y)) == u"γ(x, y)"
assert upretty(uppergamma(x, y)) == u"Γ(x, y)"
assert xpretty(gamma(x), use_unicode=True) == u'Γ(x)'
assert xpretty(gamma, use_unicode=True) == u'Γ'
assert xpretty(symbols('gamma', cls=Function)(x), use_unicode=True) == u'γ(x)'
assert xpretty(symbols('gamma', cls=Function), use_unicode=True) == u'γ'
def test_beta():
assert xpretty(beta(x,y), use_unicode=True) == u'Β(x, y)'
assert xpretty(beta(x,y), use_unicode=False) == u'B(x, y)'
assert xpretty(beta, use_unicode=True) == u'Β'
assert xpretty(beta, use_unicode=False) == u'B'
mybeta = Function('beta')
assert xpretty(mybeta(x), use_unicode=True) == u'β(x)'
assert xpretty(mybeta(x, y, z), use_unicode=False) == u'beta(x, y, z)'
assert xpretty(mybeta, use_unicode=True) == u'β'
# test that notation passes to subclasses of the same name only
def test_function_subclass_different_name():
class mygamma(gamma):
pass
assert xpretty(mygamma, use_unicode=True) == r"mygamma"
assert xpretty(mygamma(x), use_unicode=True) == r"mygamma(x)"
def test_SingularityFunction():
assert xpretty(SingularityFunction(x, 0, n), use_unicode=True) == (
"""\
n\n\
<x> \
""")
assert xpretty(SingularityFunction(x, 1, n), use_unicode=True) == (
"""\
n\n\
<x - 1> \
""")
assert xpretty(SingularityFunction(x, -1, n), use_unicode=True) == (
"""\
n\n\
<x + 1> \
""")
assert xpretty(SingularityFunction(x, a, n), use_unicode=True) == (
"""\
n\n\
<-a + x> \
""")
assert xpretty(SingularityFunction(x, y, n), use_unicode=True) == (
"""\
n\n\
<x - y> \
""")
assert xpretty(SingularityFunction(x, 0, n), use_unicode=False) == (
"""\
n\n\
<x> \
""")
assert xpretty(SingularityFunction(x, 1, n), use_unicode=False) == (
"""\
n\n\
<x - 1> \
""")
assert xpretty(SingularityFunction(x, -1, n), use_unicode=False) == (
"""\
n\n\
<x + 1> \
""")
assert xpretty(SingularityFunction(x, a, n), use_unicode=False) == (
"""\
n\n\
<-a + x> \
""")
assert xpretty(SingularityFunction(x, y, n), use_unicode=False) == (
"""\
n\n\
<x - y> \
""")
def test_deltas():
assert xpretty(DiracDelta(x), use_unicode=True) == u'δ(x)'
assert xpretty(DiracDelta(x, 1), use_unicode=True) == \
u("""\
(1) \n\
δ (x)\
""")
assert xpretty(x*DiracDelta(x, 1), use_unicode=True) == \
u("""\
(1) \n\
x⋅δ (x)\
""")
def test_hyper():
expr = hyper((), (), z)
ucode_str = \
u("""\
┌─ ⎛ │ ⎞\n\
├─ ⎜ │ z⎟\n\
0╵ 0 ⎝ │ ⎠\
""")
ascii_str = \
"""\
_ \n\
|_ / | \\\n\
| | | z|\n\
0 0 \\ | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = hyper((), (1,), x)
ucode_str = \
u("""\
┌─ ⎛ │ ⎞\n\
├─ ⎜ │ x⎟\n\
0╵ 1 ⎝1 │ ⎠\
""")
ascii_str = \
"""\
_ \n\
|_ / | \\\n\
| | | x|\n\
0 1 \\1 | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = hyper([2], [1], x)
ucode_str = \
u("""\
┌─ ⎛2 │ ⎞\n\
├─ ⎜ │ x⎟\n\
1╵ 1 ⎝1 │ ⎠\
""")
ascii_str = \
"""\
_ \n\
|_ /2 | \\\n\
| | | x|\n\
1 1 \\1 | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = hyper((pi/3, -2*k), (3, 4, 5, -3), x)
ucode_str = \
u("""\
⎛ π │ ⎞\n\
┌─ ⎜ ─, -2⋅k │ ⎟\n\
├─ ⎜ 3 │ x⎟\n\
2╵ 4 ⎜ │ ⎟\n\
⎝3, 4, 5, -3 │ ⎠\
""")
ascii_str = \
"""\
\n\
_ / pi | \\\n\
|_ | --, -2*k | |\n\
| | 3 | x|\n\
2 4 | | |\n\
\\3, 4, 5, -3 | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = hyper((pi, S('2/3'), -2*k), (3, 4, 5, -3), x**2)
ucode_str = \
u("""\
┌─ ⎛π, 2/3, -2⋅k │ 2⎞\n\
├─ ⎜ │ x ⎟\n\
3╵ 4 ⎝3, 4, 5, -3 │ ⎠\
""")
ascii_str = \
"""\
_ \n\
|_ /pi, 2/3, -2*k | 2\\\n\
| | | x |\n\
3 4 \\ 3, 4, 5, -3 | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = hyper([1, 2], [3, 4], 1/(1/(1/(1/x + 1) + 1) + 1))
ucode_str = \
u("""\
⎛ │ 1 ⎞\n\
⎜ │ ─────────────⎟\n\
⎜ │ 1 ⎟\n\
┌─ ⎜1, 2 │ 1 + ─────────⎟\n\
├─ ⎜ │ 1 ⎟\n\
2╵ 2 ⎜3, 4 │ 1 + ─────⎟\n\
⎜ │ 1⎟\n\
⎜ │ 1 + ─⎟\n\
⎝ │ x⎠\
""")
ascii_str = \
"""\
\n\
/ | 1 \\\n\
| | -------------|\n\
_ | | 1 |\n\
|_ |1, 2 | 1 + ---------|\n\
| | | 1 |\n\
2 2 |3, 4 | 1 + -----|\n\
| | 1|\n\
| | 1 + -|\n\
\\ | x/\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_meijerg():
expr = meijerg([pi, pi, x], [1], [0, 1], [1, 2, 3], z)
ucode_str = \
u("""\
╭─╮2, 3 ⎛π, π, x 1 │ ⎞\n\
│╶┐ ⎜ │ z⎟\n\
╰─╯4, 5 ⎝ 0, 1 1, 2, 3 │ ⎠\
""")
ascii_str = \
"""\
__2, 3 /pi, pi, x 1 | \\\n\
/__ | | z|\n\
\\_|4, 5 \\ 0, 1 1, 2, 3 | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = meijerg([1, pi/7], [2, pi, 5], [], [], z**2)
ucode_str = \
u("""\
⎛ π │ ⎞\n\
╭─╮0, 2 ⎜1, ─ 2, π, 5 │ 2⎟\n\
│╶┐ ⎜ 7 │ z ⎟\n\
╰─╯5, 0 ⎜ │ ⎟\n\
⎝ │ ⎠\
""")
ascii_str = \
"""\
/ pi | \\\n\
__0, 2 |1, -- 2, pi, 5 | 2|\n\
/__ | 7 | z |\n\
\\_|5, 0 | | |\n\
\\ | /\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ucode_str = \
u("""\
╭─╮ 1, 10 ⎛1, 1, 1, 1, 1, 1, 1, 1, 1, 1 1 │ ⎞\n\
│╶┐ ⎜ │ z⎟\n\
╰─╯11, 2 ⎝ 1 1 │ ⎠\
""")
ascii_str = \
"""\
__ 1, 10 /1, 1, 1, 1, 1, 1, 1, 1, 1, 1 1 | \\\n\
/__ | | z|\n\
\\_|11, 2 \\ 1 1 | /\
"""
expr = meijerg([1]*10, [1], [1], [1], z)
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = meijerg([1, 2, ], [4, 3], [3], [4, 5], 1/(1/(1/(1/x + 1) + 1) + 1))
ucode_str = \
u("""\
⎛ │ 1 ⎞\n\
⎜ │ ─────────────⎟\n\
⎜ │ 1 ⎟\n\
╭─╮1, 2 ⎜1, 2 4, 3 │ 1 + ─────────⎟\n\
│╶┐ ⎜ │ 1 ⎟\n\
╰─╯4, 3 ⎜ 3 4, 5 │ 1 + ─────⎟\n\
⎜ │ 1⎟\n\
⎜ │ 1 + ─⎟\n\
⎝ │ x⎠\
""")
ascii_str = \
"""\
/ | 1 \\\n\
| | -------------|\n\
| | 1 |\n\
__1, 2 |1, 2 4, 3 | 1 + ---------|\n\
/__ | | 1 |\n\
\\_|4, 3 | 3 4, 5 | 1 + -----|\n\
| | 1|\n\
| | 1 + -|\n\
\\ | x/\
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = Integral(expr, x)
ucode_str = \
u("""\
⌠ \n\
⎮ ⎛ │ 1 ⎞ \n\
⎮ ⎜ │ ─────────────⎟ \n\
⎮ ⎜ │ 1 ⎟ \n\
⎮ ╭─╮1, 2 ⎜1, 2 4, 3 │ 1 + ─────────⎟ \n\
⎮ │╶┐ ⎜ │ 1 ⎟ dx\n\
⎮ ╰─╯4, 3 ⎜ 3 4, 5 │ 1 + ─────⎟ \n\
⎮ ⎜ │ 1⎟ \n\
⎮ ⎜ │ 1 + ─⎟ \n\
⎮ ⎝ │ x⎠ \n\
⌡ \
""")
ascii_str = \
"""\
/ \n\
| \n\
| / | 1 \\ \n\
| | | -------------| \n\
| | | 1 | \n\
| __1, 2 |1, 2 4, 3 | 1 + ---------| \n\
| /__ | | 1 | dx\n\
| \\_|4, 3 | 3 4, 5 | 1 + -----| \n\
| | | 1| \n\
| | | 1 + -| \n\
| \\ | x/ \n\
| \n\
/ \
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_noncommutative():
A, B, C = symbols('A,B,C', commutative=False)
expr = A*B*C**-1
ascii_str = \
"""\
-1\n\
A*B*C \
"""
ucode_str = \
u("""\
-1\n\
A⋅B⋅C \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = C**-1*A*B
ascii_str = \
"""\
-1 \n\
C *A*B\
"""
ucode_str = \
u("""\
-1 \n\
C ⋅A⋅B\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A*C**-1*B
ascii_str = \
"""\
-1 \n\
A*C *B\
"""
ucode_str = \
u("""\
-1 \n\
A⋅C ⋅B\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A*C**-1*B/x
ascii_str = \
"""\
-1 \n\
A*C *B\n\
-------\n\
x \
"""
ucode_str = \
u("""\
-1 \n\
A⋅C ⋅B\n\
───────\n\
x \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_special_functions():
x, y = symbols("x y")
# atan2
expr = atan2(y/sqrt(200), sqrt(x))
ascii_str = \
"""\
/ ___ \\\n\
|\\/ 2 *y ___|\n\
atan2|-------, \\/ x |\n\
\\ 20 /\
"""
ucode_str = \
u("""\
⎛√2⋅y ⎞\n\
atan2⎜────, √x⎟\n\
⎝ 20 ⎠\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_geometry():
e = Segment((0, 1), (0, 2))
assert pretty(e) == 'Segment2D(Point2D(0, 1), Point2D(0, 2))'
e = Ray((1, 1), angle=4.02*pi)
assert pretty(e) == 'Ray2D(Point2D(1, 1), Point2D(2, tan(pi/50) + 1))'
def test_expint():
expr = Ei(x)
string = 'Ei(x)'
assert pretty(expr) == string
assert upretty(expr) == string
expr = expint(1, z)
ucode_str = u"E₁(z)"
ascii_str = "expint(1, z)"
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
assert pretty(Shi(x)) == 'Shi(x)'
assert pretty(Si(x)) == 'Si(x)'
assert pretty(Ci(x)) == 'Ci(x)'
assert pretty(Chi(x)) == 'Chi(x)'
assert upretty(Shi(x)) == 'Shi(x)'
assert upretty(Si(x)) == 'Si(x)'
assert upretty(Ci(x)) == 'Ci(x)'
assert upretty(Chi(x)) == 'Chi(x)'
def test_elliptic_functions():
ascii_str = \
"""\
/ 1 \\\n\
K|-----|\n\
\\z + 1/\
"""
ucode_str = \
u("""\
⎛ 1 ⎞\n\
K⎜─────⎟\n\
⎝z + 1⎠\
""")
expr = elliptic_k(1/(z + 1))
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ascii_str = \
"""\
/ | 1 \\\n\
F|1|-----|\n\
\\ |z + 1/\
"""
ucode_str = \
u("""\
⎛ │ 1 ⎞\n\
F⎜1│─────⎟\n\
⎝ │z + 1⎠\
""")
expr = elliptic_f(1, 1/(1 + z))
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ascii_str = \
"""\
/ 1 \\\n\
E|-----|\n\
\\z + 1/\
"""
ucode_str = \
u("""\
⎛ 1 ⎞\n\
E⎜─────⎟\n\
⎝z + 1⎠\
""")
expr = elliptic_e(1/(z + 1))
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ascii_str = \
"""\
/ | 1 \\\n\
E|1|-----|\n\
\\ |z + 1/\
"""
ucode_str = \
u("""\
⎛ │ 1 ⎞\n\
E⎜1│─────⎟\n\
⎝ │z + 1⎠\
""")
expr = elliptic_e(1, 1/(1 + z))
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ascii_str = \
"""\
/ |4\\\n\
Pi|3|-|\n\
\\ |x/\
"""
ucode_str = \
u("""\
⎛ │4⎞\n\
Π⎜3│─⎟\n\
⎝ │x⎠\
""")
expr = elliptic_pi(3, 4/x)
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
ascii_str = \
"""\
/ 4| \\\n\
Pi|3; -|6|\n\
\\ x| /\
"""
ucode_str = \
u("""\
⎛ 4│ ⎞\n\
Π⎜3; ─│6⎟\n\
⎝ x│ ⎠\
""")
expr = elliptic_pi(3, 4/x, 6)
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_RandomDomain():
from sympy.stats import Normal, Die, Exponential, pspace, where
X = Normal('x1', 0, 1)
assert upretty(where(X > 0)) == u"Domain: 0 < x₁ ∧ x₁ < ∞"
D = Die('d1', 6)
assert upretty(where(D > 4)) == u'Domain: d₁ = 5 ∨ d₁ = 6'
A = Exponential('a', 1)
B = Exponential('b', 1)
assert upretty(pspace(Tuple(A, B)).domain) == \
u'Domain: 0 ≤ a ∧ 0 ≤ b ∧ a < ∞ ∧ b < ∞'
def test_PrettyPoly():
F = QQ.frac_field(x, y)
R = QQ.poly_ring(x, y)
expr = F.convert(x/(x + y))
assert pretty(expr) == "x/(x + y)"
assert upretty(expr) == u"x/(x + y)"
expr = R.convert(x + y)
assert pretty(expr) == "x + y"
assert upretty(expr) == u"x + y"
def test_issue_6285():
assert pretty(Pow(2, -5, evaluate=False)) == '1 \n--\n 5\n2 '
assert pretty(Pow(x, (1/pi))) == 'pi___\n\\/ x '
def test_issue_6359():
assert pretty(Integral(x**2, x)**2) == \
"""\
2
/ / \\ \n\
| | | \n\
| | 2 | \n\
| | x dx| \n\
| | | \n\
\\/ / \
"""
assert upretty(Integral(x**2, x)**2) == \
u("""\
2
⎛⌠ ⎞ \n\
⎜⎮ 2 ⎟ \n\
⎜⎮ x dx⎟ \n\
⎝⌡ ⎠ \
""")
assert pretty(Sum(x**2, (x, 0, 1))**2) == \
"""\
2
/ 1 \\ \n\
| ___ | \n\
| \\ ` | \n\
| \\ 2| \n\
| / x | \n\
| /__, | \n\
\\x = 0 / \
"""
assert upretty(Sum(x**2, (x, 0, 1))**2) == \
u("""\
2
⎛ 1 ⎞ \n\
⎜ ___ ⎟ \n\
⎜ ╲ ⎟ \n\
⎜ ╲ 2⎟ \n\
⎜ ╱ x ⎟ \n\
⎜ ╱ ⎟ \n\
⎜ ‾‾‾ ⎟ \n\
⎝x = 0 ⎠ \
""")
assert pretty(Product(x**2, (x, 1, 2))**2) == \
"""\
2
/ 2 \\ \n\
|______ | \n\
|| | 2| \n\
|| | x | \n\
|| | | \n\
\\x = 1 / \
"""
assert upretty(Product(x**2, (x, 1, 2))**2) == \
u("""\
2
⎛ 2 ⎞ \n\
⎜┬────┬ ⎟ \n\
⎜│ │ 2⎟ \n\
⎜│ │ x ⎟ \n\
⎜│ │ ⎟ \n\
⎝x = 1 ⎠ \
""")
f = Function('f')
assert pretty(Derivative(f(x), x)**2) == \
"""\
2
/d \\ \n\
|--(f(x))| \n\
\\dx / \
"""
assert upretty(Derivative(f(x), x)**2) == \
u("""\
2
⎛d ⎞ \n\
⎜──(f(x))⎟ \n\
⎝dx ⎠ \
""")
def test_issue_6739():
ascii_str = \
"""\
1 \n\
-----\n\
___\n\
\\/ x \
"""
ucode_str = \
u("""\
1 \n\
──\n\
√x\
""")
assert pretty(1/sqrt(x)) == ascii_str
assert upretty(1/sqrt(x)) == ucode_str
def test_complicated_symbol_unchanged():
for symb_name in ["dexpr2_d1tau", "dexpr2^d1tau"]:
assert pretty(Symbol(symb_name)) == symb_name
def test_categories():
from sympy.categories import (Object, IdentityMorphism,
NamedMorphism, Category, Diagram, DiagramGrid)
A1 = Object("A1")
A2 = Object("A2")
A3 = Object("A3")
f1 = NamedMorphism(A1, A2, "f1")
f2 = NamedMorphism(A2, A3, "f2")
id_A1 = IdentityMorphism(A1)
K1 = Category("K1")
assert pretty(A1) == "A1"
assert upretty(A1) == u"A₁"
assert pretty(f1) == "f1:A1-->A2"
assert upretty(f1) == u"f₁:A₁——▶A₂"
assert pretty(id_A1) == "id:A1-->A1"
assert upretty(id_A1) == u"id:A₁——▶A₁"
assert pretty(f2*f1) == "f2*f1:A1-->A3"
assert upretty(f2*f1) == u"f₂∘f₁:A₁——▶A₃"
assert pretty(K1) == "K1"
assert upretty(K1) == u"K₁"
# Test how diagrams are printed.
d = Diagram()
assert pretty(d) == "EmptySet()"
assert upretty(d) == u"∅"
d = Diagram({f1: "unique", f2: S.EmptySet})
assert pretty(d) == "{f2*f1:A1-->A3: EmptySet(), id:A1-->A1: " \
"EmptySet(), id:A2-->A2: EmptySet(), id:A3-->A3: " \
"EmptySet(), f1:A1-->A2: {unique}, f2:A2-->A3: EmptySet()}"
assert upretty(d) == u("{f₂∘f₁:A₁——▶A₃: ∅, id:A₁——▶A₁: ∅, " \
"id:A₂——▶A₂: ∅, id:A₃——▶A₃: ∅, f₁:A₁——▶A₂: {unique}, f₂:A₂——▶A₃: ∅}")
d = Diagram({f1: "unique", f2: S.EmptySet}, {f2 * f1: "unique"})
assert pretty(d) == "{f2*f1:A1-->A3: EmptySet(), id:A1-->A1: " \
"EmptySet(), id:A2-->A2: EmptySet(), id:A3-->A3: " \
"EmptySet(), f1:A1-->A2: {unique}, f2:A2-->A3: EmptySet()}" \
" ==> {f2*f1:A1-->A3: {unique}}"
assert upretty(d) == u("{f₂∘f₁:A₁——▶A₃: ∅, id:A₁——▶A₁: ∅, id:A₂——▶A₂: " \
"∅, id:A₃——▶A₃: ∅, f₁:A₁——▶A₂: {unique}, f₂:A₂——▶A₃: ∅}" \
" ══▶ {f₂∘f₁:A₁——▶A₃: {unique}}")
grid = DiagramGrid(d)
assert pretty(grid) == "A1 A2\n \nA3 "
assert upretty(grid) == u"A₁ A₂\n \nA₃ "
def test_PrettyModules():
R = QQ.old_poly_ring(x, y)
F = R.free_module(2)
M = F.submodule([x, y], [1, x**2])
ucode_str = \
u("""\
2\n\
ℚ[x, y] \
""")
ascii_str = \
"""\
2\n\
QQ[x, y] \
"""
assert upretty(F) == ucode_str
assert pretty(F) == ascii_str
ucode_str = \
u("""\
╱ ⎡ 2⎤╲\n\
╲[x, y], ⎣1, x ⎦╱\
""")
ascii_str = \
"""\
2 \n\
<[x, y], [1, x ]>\
"""
assert upretty(M) == ucode_str
assert pretty(M) == ascii_str
I = R.ideal(x**2, y)
ucode_str = \
u("""\
╱ 2 ╲\n\
╲x , y╱\
""")
ascii_str = \
"""\
2 \n\
<x , y>\
"""
assert upretty(I) == ucode_str
assert pretty(I) == ascii_str
Q = F / M
ucode_str = \
u("""\
2 \n\
ℚ[x, y] \n\
─────────────────\n\
╱ ⎡ 2⎤╲\n\
╲[x, y], ⎣1, x ⎦╱\
""")
ascii_str = \
"""\
2 \n\
QQ[x, y] \n\
-----------------\n\
2 \n\
<[x, y], [1, x ]>\
"""
assert upretty(Q) == ucode_str
assert pretty(Q) == ascii_str
ucode_str = \
u("""\
╱⎡ 3⎤ ╲\n\
│⎢ x ⎥ ╱ ⎡ 2⎤╲ ╱ ⎡ 2⎤╲│\n\
│⎢1, ──⎥ + ╲[x, y], ⎣1, x ⎦╱, [2, y] + ╲[x, y], ⎣1, x ⎦╱│\n\
╲⎣ 2 ⎦ ╱\
""")
ascii_str = \
"""\
3 \n\
x 2 2 \n\
<[1, --] + <[x, y], [1, x ]>, [2, y] + <[x, y], [1, x ]>>\n\
2 \
"""
def test_QuotientRing():
R = QQ.old_poly_ring(x)/[x**2 + 1]
ucode_str = \
u("""\
ℚ[x] \n\
────────\n\
╱ 2 ╲\n\
╲x + 1╱\
""")
ascii_str = \
"""\
QQ[x] \n\
--------\n\
2 \n\
<x + 1>\
"""
assert upretty(R) == ucode_str
assert pretty(R) == ascii_str
ucode_str = \
u("""\
╱ 2 ╲\n\
1 + ╲x + 1╱\
""")
ascii_str = \
"""\
2 \n\
1 + <x + 1>\
"""
assert upretty(R.one) == ucode_str
assert pretty(R.one) == ascii_str
def test_Homomorphism():
from sympy.polys.agca import homomorphism
R = QQ.old_poly_ring(x)
expr = homomorphism(R.free_module(1), R.free_module(1), [0])
ucode_str = \
u("""\
1 1\n\
[0] : ℚ[x] ──> ℚ[x] \
""")
ascii_str = \
"""\
1 1\n\
[0] : QQ[x] --> QQ[x] \
"""
assert upretty(expr) == ucode_str
assert pretty(expr) == ascii_str
expr = homomorphism(R.free_module(2), R.free_module(2), [0, 0])
ucode_str = \
u("""\
⎡0 0⎤ 2 2\n\
⎢ ⎥ : ℚ[x] ──> ℚ[x] \n\
⎣0 0⎦ \
""")
ascii_str = \
"""\
[0 0] 2 2\n\
[ ] : QQ[x] --> QQ[x] \n\
[0 0] \
"""
assert upretty(expr) == ucode_str
assert pretty(expr) == ascii_str
expr = homomorphism(R.free_module(1), R.free_module(1) / [[x]], [0])
ucode_str = \
u("""\
1\n\
1 ℚ[x] \n\
[0] : ℚ[x] ──> ─────\n\
<[x]>\
""")
ascii_str = \
"""\
1\n\
1 QQ[x] \n\
[0] : QQ[x] --> ------\n\
<[x]> \
"""
assert upretty(expr) == ucode_str
assert pretty(expr) == ascii_str
def test_Tr():
A, B = symbols('A B', commutative=False)
t = Tr(A*B)
assert pretty(t) == r'Tr(A*B)'
assert upretty(t) == u'Tr(A⋅B)'
def test_pretty_Add():
eq = Mul(-2, x - 2, evaluate=False) + 5
assert pretty(eq) == '-2*(x - 2) + 5'
def test_issue_7179():
assert upretty(Not(Equivalent(x, y))) == u'x ⇎ y'
assert upretty(Not(Implies(x, y))) == u'x ↛ y'
def test_issue_7180():
assert upretty(Equivalent(x, y)) == u'x ⇔ y'
def test_pretty_Complement():
assert pretty(S.Reals - S.Naturals) == '(-oo, oo) \\ Naturals'
assert upretty(S.Reals - S.Naturals) == u'ℝ \\ ℕ'
assert pretty(S.Reals - S.Naturals0) == '(-oo, oo) \\ Naturals0'
assert upretty(S.Reals - S.Naturals0) == u'ℝ \\ ℕ₀'
def test_pretty_SymmetricDifference():
from sympy import SymmetricDifference, Interval
from sympy.utilities.pytest import raises
assert upretty(SymmetricDifference(Interval(2,3), Interval(3,5), \
evaluate = False)) == u'[2, 3] ∆ [3, 5]'
with raises(NotImplementedError):
pretty(SymmetricDifference(Interval(2,3), Interval(3,5), evaluate = False))
def test_pretty_Contains():
assert pretty(Contains(x, S.Integers)) == 'Contains(x, Integers)'
assert upretty(Contains(x, S.Integers)) == u'x ∈ ℤ'
def test_issue_8292():
from sympy.core import sympify
e = sympify('((x+x**4)/(x-1))-(2*(x-1)**4/(x-1)**4)', evaluate=False)
ucode_str = \
u("""\
4 4 \n\
2⋅(x - 1) x + x\n\
- ────────── + ──────\n\
4 x - 1 \n\
(x - 1) \
""")
ascii_str = \
"""\
4 4 \n\
2*(x - 1) x + x\n\
- ---------- + ------\n\
4 x - 1 \n\
(x - 1) \
"""
assert pretty(e) == ascii_str
assert upretty(e) == ucode_str
def test_issue_4335():
y = Function('y')
expr = -y(x).diff(x)
ucode_str = \
u("""\
d \n\
-──(y(x))\n\
dx \
""")
ascii_str = \
"""\
d \n\
- --(y(x))\n\
dx \
"""
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_issue_8344():
from sympy.core import sympify
e = sympify('2*x*y**2/1**2 + 1', evaluate=False)
ucode_str = \
u("""\
2 \n\
2⋅x⋅y \n\
────── + 1\n\
2 \n\
1 \
""")
assert upretty(e) == ucode_str
def test_issue_6324():
x = Pow(2, 3, evaluate=False)
y = Pow(10, -2, evaluate=False)
e = Mul(x, y, evaluate=False)
ucode_str = \
u("""\
3\n\
2 \n\
───\n\
2\n\
10 \
""")
assert upretty(e) == ucode_str
def test_issue_7927():
e = sin(x/2)**cos(x/2)
ucode_str = \
u("""\
⎛x⎞\n\
cos⎜─⎟\n\
⎝2⎠\n\
⎛ ⎛x⎞⎞ \n\
⎜sin⎜─⎟⎟ \n\
⎝ ⎝2⎠⎠ \
""")
assert upretty(e) == ucode_str
e = sin(x)**(S(11)/13)
ucode_str = \
u("""\
11\n\
──\n\
13\n\
(sin(x)) \
""")
assert upretty(e) == ucode_str
def test_issue_6134():
from sympy.abc import lamda, t
phi = Function('phi')
e = lamda*x*Integral(phi(t)*pi*sin(pi*t), (t, 0, 1)) + lamda*x**2*Integral(phi(t)*2*pi*sin(2*pi*t), (t, 0, 1))
ucode_str = \
u("""\
1 1 \n\
2 ⌠ ⌠ \n\
λ⋅x ⋅⎮ 2⋅π⋅φ(t)⋅sin(2⋅π⋅t) dt + λ⋅x⋅⎮ π⋅φ(t)⋅sin(π⋅t) dt\n\
⌡ ⌡ \n\
0 0 \
""")
assert upretty(e) == ucode_str
def test_issue_9877():
ucode_str1 = u'(2, 3) ∪ ([1, 2] \\ {x})'
a, b, c = Interval(2, 3, True, True), Interval(1, 2), FiniteSet(x)
assert upretty(Union(a, Complement(b, c))) == ucode_str1
ucode_str2 = u'{x} ∩ {y} ∩ ({z} \\ [1, 2])'
d, e, f, g = FiniteSet(x), FiniteSet(y), FiniteSet(z), Interval(1, 2)
assert upretty(Intersection(d, e, Complement(f, g))) == ucode_str2
def test_issue_13651():
expr1 = c + Mul(-1, a + b, evaluate=False)
assert pretty(expr1) == 'c - (a + b)'
expr2 = c + Mul(-1, a - b + d, evaluate=False)
assert pretty(expr2) == 'c - (a - b + d)'
def test_pretty_primenu():
from sympy.ntheory.factor_ import primenu
ascii_str1 = "nu(n)"
ucode_str1 = u("ν(n)")
n = symbols('n', integer=True)
assert pretty(primenu(n)) == ascii_str1
assert upretty(primenu(n)) == ucode_str1
def test_pretty_primeomega():
from sympy.ntheory.factor_ import primeomega
ascii_str1 = "Omega(n)"
ucode_str1 = u("Ω(n)")
n = symbols('n', integer=True)
assert pretty(primeomega(n)) == ascii_str1
assert upretty(primeomega(n)) == ucode_str1
def test_pretty_Mod():
from sympy.core import Mod
ascii_str1 = "x mod 7"
ucode_str1 = u("x mod 7")
ascii_str2 = "(x + 1) mod 7"
ucode_str2 = u("(x + 1) mod 7")
ascii_str3 = "2*x mod 7"
ucode_str3 = u("2⋅x mod 7")
ascii_str4 = "(x mod 7) + 1"
ucode_str4 = u("(x mod 7) + 1")
ascii_str5 = "2*(x mod 7)"
ucode_str5 = u("2⋅(x mod 7)")
x = symbols('x', integer=True)
assert pretty(Mod(x, 7)) == ascii_str1
assert upretty(Mod(x, 7)) == ucode_str1
assert pretty(Mod(x + 1, 7)) == ascii_str2
assert upretty(Mod(x + 1, 7)) == ucode_str2
assert pretty(Mod(2 * x, 7)) == ascii_str3
assert upretty(Mod(2 * x, 7)) == ucode_str3
assert pretty(Mod(x, 7) + 1) == ascii_str4
assert upretty(Mod(x, 7) + 1) == ucode_str4
assert pretty(2 * Mod(x, 7)) == ascii_str5
assert upretty(2 * Mod(x, 7)) == ucode_str5
def test_issue_11801():
assert pretty(Symbol("")) == ""
assert upretty(Symbol("")) == ""
def test_pretty_UnevaluatedExpr():
x = symbols('x')
he = UnevaluatedExpr(1/x)
ucode_str = \
u("""\
1\n\
─\n\
x\
""")
assert upretty(he) == ucode_str
ucode_str = \
u("""\
2\n\
⎛1⎞ \n\
⎜─⎟ \n\
⎝x⎠ \
""")
assert upretty(he**2) == ucode_str
ucode_str = \
u("""\
1\n\
1 + ─\n\
x\
""")
assert upretty(he + 1) == ucode_str
ucode_str = \
u('''\
1\n\
x⋅─\n\
x\
''')
assert upretty(x*he) == ucode_str
def test_issue_10472():
M = (Matrix([[0, 0], [0, 0]]), Matrix([0, 0]))
ucode_str = \
u("""\
⎛⎡0 0⎤ ⎡0⎤⎞
⎜⎢ ⎥, ⎢ ⎥⎟
⎝⎣0 0⎦ ⎣0⎦⎠\
""")
assert upretty(M) == ucode_str
def test_MatrixElement_printing():
# test cases for issue #11821
A = MatrixSymbol("A", 1, 3)
B = MatrixSymbol("B", 1, 3)
C = MatrixSymbol("C", 1, 3)
ascii_str1 = "A_00"
ucode_str1 = u("A₀₀")
assert pretty(A[0, 0]) == ascii_str1
assert upretty(A[0, 0]) == ucode_str1
ascii_str1 = "3*A_00"
ucode_str1 = u("3⋅A₀₀")
assert pretty(3*A[0, 0]) == ascii_str1
assert upretty(3*A[0, 0]) == ucode_str1
ascii_str1 = "(-B + A)[0, 0]"
ucode_str1 = u("(-B + A)[0, 0]")
F = C[0, 0].subs(C, A - B)
assert pretty(F) == ascii_str1
assert upretty(F) == ucode_str1
def test_issue_12675():
from sympy.vector import CoordSys3D
x, y, t, j = symbols('x y t j')
e = CoordSys3D('e')
ucode_str = \
u("""\
⎛ t⎞ \n\
⎜⎛x⎞ ⎟ e_j\n\
⎜⎜─⎟ ⎟ \n\
⎝⎝y⎠ ⎠ \
""")
assert upretty((x/y)**t*e.j) == ucode_str
ucode_str = \
u("""\
⎛1⎞ \n\
⎜─⎟ e_j\n\
⎝y⎠ \
""")
assert upretty((1/y)*e.j) == ucode_str
def test_MatrixSymbol_printing():
# test cases for issue #14237
A = MatrixSymbol("A", 3, 3)
B = MatrixSymbol("B", 3, 3)
C = MatrixSymbol("C", 3, 3)
assert pretty(-A*B*C) == "-A*B*C"
assert pretty(A - B) == "-B + A"
assert pretty(A*B*C - A*B - B*C) == "-A*B -B*C + A*B*C"
# issue #14814
x = MatrixSymbol('x', n, n)
y = MatrixSymbol('y*', n, n)
assert pretty(x + y) == "x + y*"
ascii_str = \
"""\
2 \n\
-2*y* -a*x\
"""
assert pretty(-a*x + -2*y*y) == ascii_str
def test_degree_printing():
expr1 = 90*degree
assert pretty(expr1) == u'90°'
expr2 = x*degree
assert pretty(expr2) == u'x°'
expr3 = cos(x*degree + 90*degree)
assert pretty(expr3) == u'cos(x° + 90°)'
def test_vector_expr_pretty_printing():
A = CoordSys3D('A')
assert upretty(Cross(A.i, A.x*A.i+3*A.y*A.j)) == u("(A_i)×((A_x) A_i + (3⋅A_y) A_j)")
assert upretty(x*Cross(A.i, A.j)) == u('x⋅(A_i)×(A_j)')
assert upretty(Curl(A.x*A.i + 3*A.y*A.j)) == u("∇×((A_x) A_i + (3⋅A_y) A_j)")
assert upretty(Divergence(A.x*A.i + 3*A.y*A.j)) == u("∇⋅((A_x) A_i + (3⋅A_y) A_j)")
assert upretty(Dot(A.i, A.x*A.i+3*A.y*A.j)) == u("(A_i)⋅((A_x) A_i + (3⋅A_y) A_j)")
assert upretty(Gradient(A.x+3*A.y)) == u("∇⋅(A_x + 3⋅A_y)")
# TODO: add support for ASCII pretty.
def test_pretty_print_tensor_expr():
L = TensorIndexType("L")
i, j, k = tensor_indices("i j k", L)
i0 = tensor_indices("i_0", L)
A, B, C, D = tensorhead("A B C D", [L], [[1]])
H = tensorhead("H", [L, L], [[1], [1]])
expr = -i
ascii_str = \
"""\
-i\
"""
ucode_str = \
u("""\
-i\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(i)
ascii_str = \
"""\
i\n\
A \n\
\
"""
ucode_str = \
u("""\
i\n\
A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(i0)
ascii_str = \
"""\
i_0\n\
A \n\
\
"""
ucode_str = \
u("""\
i₀\n\
A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(-i)
ascii_str = \
"""\
\n\
A \n\
i\
"""
ucode_str = \
u("""\
\n\
A \n\
i\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = -3*A(-i)
ascii_str = \
"""\
\n\
-3*A \n\
i\
"""
ucode_str = \
u("""\
\n\
-3⋅A \n\
i\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = H(i, -j)
ascii_str = \
"""\
i \n\
H \n\
j\
"""
ucode_str = \
u("""\
i \n\
H \n\
j\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = H(i, -i)
ascii_str = \
"""\
L_0 \n\
H \n\
L_0\
"""
ucode_str = \
u("""\
L₀ \n\
H \n\
L₀\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = H(i, -j)*A(j)*B(k)
ascii_str = \
"""\
i L_0 k\n\
H *A *B \n\
L_0 \
"""
ucode_str = \
u("""\
i L₀ k\n\
H ⋅A ⋅B \n\
L₀ \
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (1+x)*A(i)
ascii_str = \
"""\
i\n\
(x + 1)*A \n\
\
"""
ucode_str = \
u("""\
i\n\
(x + 1)⋅A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(i) + 3*B(i)
ascii_str = \
"""\
i i\n\
A + 3*B \n\
\
"""
ucode_str = \
u("""\
i i\n\
A + 3⋅B \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_pretty_print_tensor_partial_deriv():
from sympy.tensor.toperators import PartialDerivative
from sympy.tensor.tensor import TensorIndexType, tensor_indices, tensorhead
L = TensorIndexType("L")
i, j, k = tensor_indices("i j k", L)
i0 = tensor_indices("i0", L)
A, B, C, D = tensorhead("A B C D", [L], [[1]])
H = tensorhead("H", [L, L], [[1], [1]])
expr = PartialDerivative(A(i), A(j))
ascii_str = \
"""\
d / i\\\n\
---|A |\n\
j\\ /\n\
dA \n\
\
"""
ucode_str = \
u("""\
∂ ⎛ i⎞\n\
───⎜A ⎟\n\
j⎝ ⎠\n\
∂A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(i)*PartialDerivative(H(k, -i), A(j))
ascii_str = \
"""\
L_0 d / k \\\n\
A *---|H |\n\
j\\ L_0/\n\
dA \n\
\
"""
ucode_str = \
u("""\
L₀ ∂ ⎛ k ⎞\n\
A ⋅───⎜H ⎟\n\
j⎝ L₀⎠\n\
∂A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = A(i)*PartialDerivative(B(k)*C(-i) + 3*H(k, -i), A(j))
ascii_str = \
"""\
L_0 d / k k \\\n\
A *---|B *C + 3*H |\n\
j\\ L_0 L_0/\n\
dA \n\
\
"""
ucode_str = \
u("""\
L₀ ∂ ⎛ k k ⎞\n\
A ⋅───⎜B ⋅C + 3⋅H ⎟\n\
j⎝ L₀ L₀⎠\n\
∂A \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (A(i) + B(i))*PartialDerivative(C(-j), D(j))
ascii_str = \
"""\
/ i i\\ d / \\\n\
|A + B |*-----|C |\n\
\\ / L_0\\ L_0/\n\
dD \n\
\
"""
ucode_str = \
u("""\
⎛ i i⎞ ∂ ⎛ ⎞\n\
⎜A + B ⎟⋅────⎜C ⎟\n\
⎝ ⎠ L₀⎝ L₀⎠\n\
∂D \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = (A(i) + B(i))*PartialDerivative(C(-i), D(j))
ascii_str = \
"""\
/ L_0 L_0\\ d / \\\n\
|A + B |*---|C |\n\
\\ / j\\ L_0/\n\
dD \n\
\
"""
ucode_str = \
u("""\
⎛ L₀ L₀⎞ ∂ ⎛ ⎞\n\
⎜A + B ⎟⋅───⎜C ⎟\n\
⎝ ⎠ j⎝ L₀⎠\n\
∂D \n\
\
""")
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = TensorElement(H(i, j), {i:1})
ascii_str = \
"""\
i=1,j\n\
H \n\
\
"""
ucode_str = ascii_str
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = TensorElement(H(i, j), {i:1, j:1})
ascii_str = \
"""\
i=1,j=1\n\
H \n\
\
"""
ucode_str = ascii_str
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
expr = TensorElement(H(i, j), {j:1})
ascii_str = \
"""\
i,j=1\n\
H \n\
\
"""
ucode_str = ascii_str
expr = TensorElement(H(-i, j), {-i:1})
ascii_str = \
"""\
j\n\
H \n\
i=1 \
"""
ucode_str = ascii_str
assert pretty(expr) == ascii_str
assert upretty(expr) == ucode_str
def test_issue_15560():
a = MatrixSymbol('a', 1, 1)
e = pretty(a*(KroneckerProduct(a, a)))
result = 'a*(a x a)'
assert e == result
def test_issue_15583():
N = mechanics.ReferenceFrame('N')
result = '(n_x, n_y, n_z)'
e = pretty((N.x, N.y, N.z))
assert e == result
|
a14bafc0d48e691ecac81c6c465129bf541825486d808b1e247df2af7dcec473
|
from sympy import (
Abs, acos, acosh, Add, And, asin, asinh, atan, Ci, cos, sinh, cosh,
tanh, Derivative, diff, DiracDelta, E, Ei, Eq, exp, erf, erfc, erfi,
EulerGamma, Expr, factor, Function, gamma, gammasimp, I, Idx, im, IndexedBase,
Integral, integrate, Interval, Lambda, LambertW, log, Matrix, Max, meijerg, Min, nan,
Ne, O, oo, pi, Piecewise, polar_lift, Poly, polygamma, Rational, re, S, Si, sign,
simplify, sin, sinc, SingularityFunction, sqrt, sstr, Sum, Symbol,
symbols, sympify, tan, trigsimp, Tuple
)
from sympy.functions.elementary.complexes import periodic_argument
from sympy.functions.elementary.integers import floor
from sympy.integrals.risch import NonElementaryIntegral
from sympy.physics import units
from sympy.core.compatibility import range
from sympy.utilities.pytest import XFAIL, raises, slow, skip, ON_TRAVIS
from sympy.utilities.randtest import verify_numerically
from sympy.integrals.integrals import Integral
x, y, a, t, x_1, x_2, z, s = symbols('x y a t x_1 x_2 z s')
n = Symbol('n', integer=True)
f = Function('f')
def test_principal_value():
g = 1 / x
assert Integral(g, (x, -oo, oo)).principal_value() == 0
assert Integral(g, (y, -oo, oo)).principal_value() == oo * sign(1 / x)
raises(ValueError, lambda: Integral(g, (x)).principal_value())
raises(ValueError, lambda: Integral(g).principal_value())
l = 1 / ((x ** 3) - 1)
assert Integral(l, (x, -oo, oo)).principal_value() == -sqrt(3)*pi/3
raises(ValueError, lambda: Integral(l, (x, -oo, 1)).principal_value())
d = 1 / (x ** 2 - 1)
assert Integral(d, (x, -oo, oo)).principal_value() == 0
assert Integral(d, (x, -2, 2)).principal_value() == -log(3)
v = x / (x ** 2 - 1)
assert Integral(v, (x, -oo, oo)).principal_value() == 0
assert Integral(v, (x, -2, 2)).principal_value() == 0
s = x ** 2 / (x ** 2 - 1)
assert Integral(s, (x, -oo, oo)).principal_value() == oo
assert Integral(s, (x, -2, 2)).principal_value() == -log(3) + 4
f = 1 / ((x ** 2 - 1) * (1 + x ** 2))
assert Integral(f, (x, -oo, oo)).principal_value() == -pi / 2
assert Integral(f, (x, -2, 2)).principal_value() == -atan(2) - log(3) / 2
def diff_test(i):
"""Return the set of symbols, s, which were used in testing that
i.diff(s) agrees with i.doit().diff(s). If there is an error then
the assertion will fail, causing the test to fail."""
syms = i.free_symbols
for s in syms:
assert (i.diff(s).doit() - i.doit().diff(s)).expand() == 0
return syms
def test_improper_integral():
assert integrate(log(x), (x, 0, 1)) == -1
assert integrate(x**(-2), (x, 1, oo)) == 1
assert integrate(1/(1 + exp(x)), (x, 0, oo)) == log(2)
def test_constructor():
# this is shared by Sum, so testing Integral's constructor
# is equivalent to testing Sum's
s1 = Integral(n, n)
assert s1.limits == (Tuple(n),)
s2 = Integral(n, (n,))
assert s2.limits == (Tuple(n),)
s3 = Integral(Sum(x, (x, 1, y)))
assert s3.limits == (Tuple(y),)
s4 = Integral(n, Tuple(n,))
assert s4.limits == (Tuple(n),)
s5 = Integral(n, (n, Interval(1, 2)))
assert s5.limits == (Tuple(n, 1, 2),)
# Testing constructor with inequalities:
s6 = Integral(n, n > 10)
assert s6.limits == (Tuple(n, 10, oo),)
s7 = Integral(n, (n > 2) & (n < 5))
assert s7.limits == (Tuple(n, 2, 5),)
def test_basics():
assert Integral(0, x) != 0
assert Integral(x, (x, 1, 1)) != 0
assert Integral(oo, x) != oo
assert Integral(S.NaN, x) == S.NaN
assert diff(Integral(y, y), x) == 0
assert diff(Integral(x, (x, 0, 1)), x) == 0
assert diff(Integral(x, x), x) == x
assert diff(Integral(t, (t, 0, x)), x) == x
e = (t + 1)**2
assert diff(integrate(e, (t, 0, x)), x) == \
diff(Integral(e, (t, 0, x)), x).doit().expand() == \
((1 + x)**2).expand()
assert diff(integrate(e, (t, 0, x)), t) == \
diff(Integral(e, (t, 0, x)), t) == 0
assert diff(integrate(e, (t, 0, x)), a) == \
diff(Integral(e, (t, 0, x)), a) == 0
assert diff(integrate(e, t), a) == diff(Integral(e, t), a) == 0
assert integrate(e, (t, a, x)).diff(x) == \
Integral(e, (t, a, x)).diff(x).doit().expand()
assert Integral(e, (t, a, x)).diff(x).doit() == ((1 + x)**2)
assert integrate(e, (t, x, a)).diff(x).doit() == (-(1 + x)**2).expand()
assert integrate(t**2, (t, x, 2*x)).diff(x) == 7*x**2
assert Integral(x, x).atoms() == {x}
assert Integral(f(x), (x, 0, 1)).atoms() == {S(0), S(1), x}
assert diff_test(Integral(x, (x, 3*y))) == {y}
assert diff_test(Integral(x, (a, 3*y))) == {x, y}
assert integrate(x, (x, oo, oo)) == 0 #issue 8171
assert integrate(x, (x, -oo, -oo)) == 0
# sum integral of terms
assert integrate(y + x + exp(x), x) == x*y + x**2/2 + exp(x)
assert Integral(x).is_commutative
n = Symbol('n', commutative=False)
assert Integral(n + x, x).is_commutative is False
def test_diff_wrt():
class Test(Expr):
_diff_wrt = True
is_commutative = True
t = Test()
assert integrate(t + 1, t) == t**2/2 + t
assert integrate(t + 1, (t, 0, 1)) == S(3)/2
raises(ValueError, lambda: integrate(x + 1, x + 1))
raises(ValueError, lambda: integrate(x + 1, (x + 1, 0, 1)))
def test_basics_multiple():
assert diff_test(Integral(x, (x, 3*x, 5*y), (y, x, 2*x))) == {x}
assert diff_test(Integral(x, (x, 5*y), (y, x, 2*x))) == {x}
assert diff_test(Integral(x, (x, 5*y), (y, y, 2*x))) == {x, y}
assert diff_test(Integral(y, y, x)) == {x, y}
assert diff_test(Integral(y*x, x, y)) == {x, y}
assert diff_test(Integral(x + y, y, (y, 1, x))) == {x}
assert diff_test(Integral(x + y, (x, x, y), (y, y, x))) == {x, y}
def test_conjugate_transpose():
A, B = symbols("A B", commutative=False)
x = Symbol("x", complex=True)
p = Integral(A*B, (x,))
assert p.adjoint().doit() == p.doit().adjoint()
assert p.conjugate().doit() == p.doit().conjugate()
assert p.transpose().doit() == p.doit().transpose()
x = Symbol("x", real=True)
p = Integral(A*B, (x,))
assert p.adjoint().doit() == p.doit().adjoint()
assert p.conjugate().doit() == p.doit().conjugate()
assert p.transpose().doit() == p.doit().transpose()
def test_integration():
assert integrate(0, (t, 0, x)) == 0
assert integrate(3, (t, 0, x)) == 3*x
assert integrate(t, (t, 0, x)) == x**2/2
assert integrate(3*t, (t, 0, x)) == 3*x**2/2
assert integrate(3*t**2, (t, 0, x)) == x**3
assert integrate(1/t, (t, 1, x)) == log(x)
assert integrate(-1/t**2, (t, 1, x)) == 1/x - 1
assert integrate(t**2 + 5*t - 8, (t, 0, x)) == x**3/3 + 5*x**2/2 - 8*x
assert integrate(x**2, x) == x**3/3
assert integrate((3*t*x)**5, x) == (3*t)**5 * x**6 / 6
b = Symbol("b")
c = Symbol("c")
assert integrate(a*t, (t, 0, x)) == a*x**2/2
assert integrate(a*t**4, (t, 0, x)) == a*x**5/5
assert integrate(a*t**2 + b*t + c, (t, 0, x)) == a*x**3/3 + b*x**2/2 + c*x
def test_multiple_integration():
assert integrate((x**2)*(y**2), (x, 0, 1), (y, -1, 2)) == Rational(1)
assert integrate((y**2)*(x**2), x, y) == Rational(1, 9)*(x**3)*(y**3)
assert integrate(1/(x + 3)/(1 + x)**3, x) == \
-S(1)/8*log(3 + x) + S(1)/8*log(1 + x) + x/(4 + 8*x + 4*x**2)
assert integrate(sin(x*y)*y, (x, 0, 1), (y, 0, 1)) == -sin(1) + 1
def test_issue_3532():
assert integrate(exp(-x), (x, 0, oo)) == 1
def test_issue_3560():
assert integrate(sqrt(x)**3, x) == 2*sqrt(x)**5/5
assert integrate(sqrt(x), x) == 2*sqrt(x)**3/3
assert integrate(1/sqrt(x)**3, x) == -2/sqrt(x)
def test_integrate_poly():
p = Poly(x + x**2*y + y**3, x, y)
qx = integrate(p, x)
qy = integrate(p, y)
assert isinstance(qx, Poly) is True
assert isinstance(qy, Poly) is True
assert qx.gens == (x, y)
assert qy.gens == (x, y)
assert qx.as_expr() == x**2/2 + x**3*y/3 + x*y**3
assert qy.as_expr() == x*y + x**2*y**2/2 + y**4/4
def test_integrate_poly_defined():
p = Poly(x + x**2*y + y**3, x, y)
Qx = integrate(p, (x, 0, 1))
Qy = integrate(p, (y, 0, pi))
assert isinstance(Qx, Poly) is True
assert isinstance(Qy, Poly) is True
assert Qx.gens == (y,)
assert Qy.gens == (x,)
assert Qx.as_expr() == Rational(1, 2) + y/3 + y**3
assert Qy.as_expr() == pi**4/4 + pi*x + pi**2*x**2/2
def test_integrate_omit_var():
y = Symbol('y')
assert integrate(x) == x**2/2
raises(ValueError, lambda: integrate(2))
raises(ValueError, lambda: integrate(x*y))
def test_integrate_poly_accurately():
y = Symbol('y')
assert integrate(x*sin(y), x) == x**2*sin(y)/2
# when passed to risch_norman, this will be a CPU hog, so this really
# checks, that integrated function is recognized as polynomial
assert integrate(x**1000*sin(y), x) == x**1001*sin(y)/1001
def test_issue_3635():
y = Symbol('y')
assert integrate(x**2, y) == x**2*y
assert integrate(x**2, (y, -1, 1)) == 2*x**2
# works in sympy and py.test but hangs in `setup.py test`
def test_integrate_linearterm_pow():
# check integrate((a*x+b)^c, x) -- issue 3499
y = Symbol('y', positive=True)
# TODO: Remove conds='none' below, let the assumption take care of it.
assert integrate(x**y, x, conds='none') == x**(y + 1)/(y + 1)
assert integrate((exp(y)*x + 1/y)**(1 + sin(y)), x, conds='none') == \
exp(-y)*(exp(y)*x + 1/y)**(2 + sin(y)) / (2 + sin(y))
def test_issue_3618():
assert integrate(pi*sqrt(x), x) == 2*pi*sqrt(x)**3/3
assert integrate(pi*sqrt(x) + E*sqrt(x)**3, x) == \
2*pi*sqrt(x)**3/3 + 2*E *sqrt(x)**5/5
def test_issue_3623():
assert integrate(cos((n + 1)*x), x) == Piecewise(
(sin(x*(n + 1))/(n + 1), Ne(n + 1, 0)), (x, True))
assert integrate(cos((n - 1)*x), x) == Piecewise(
(sin(x*(n - 1))/(n - 1), Ne(n - 1, 0)), (x, True))
assert integrate(cos((n + 1)*x) + cos((n - 1)*x), x) == \
Piecewise((sin(x*(n - 1))/(n - 1), Ne(n - 1, 0)), (x, True)) + \
Piecewise((sin(x*(n + 1))/(n + 1), Ne(n + 1, 0)), (x, True))
def test_issue_3664():
n = Symbol('n', integer=True, nonzero=True)
assert integrate(-1./2 * x * sin(n * pi * x/2), [x, -2, 0]) == \
2*cos(pi*n)/(pi*n)
assert integrate(-Rational(1)/2 * x * sin(n * pi * x/2), [x, -2, 0]) == \
2*cos(pi*n)/(pi*n)
def test_issue_3679():
# definite integration of rational functions gives wrong answers
assert NS(Integral(1/(x**2 - 8*x + 17), (x, 2, 4))) == '1.10714871779409'
def test_issue_3686(): # remove this when fresnel itegrals are implemented
from sympy import expand_func, fresnels
assert expand_func(integrate(sin(x**2), x)) == \
sqrt(2)*sqrt(pi)*fresnels(sqrt(2)*x/sqrt(pi))/2
def test_integrate_units():
m = units.m
s = units.s
assert integrate(x * m/s, (x, 1*s, 5*s)) == 12*m*s
def test_transcendental_functions():
assert integrate(LambertW(2*x), x) == \
-x + x*LambertW(2*x) + x/LambertW(2*x)
def test_log_polylog():
assert integrate(log(1 - x)/x, (x, 0, 1)) == -pi**2/6
assert integrate(log(x)*(1 - x)**(-1), (x, 0, 1)) == -pi**2/6
def test_issue_3740():
f = 4*log(x) - 2*log(x)**2
fid = diff(integrate(f, x), x)
assert abs(f.subs(x, 42).evalf() - fid.subs(x, 42).evalf()) < 1e-10
def test_issue_3788():
assert integrate(1/(1 + x**2), x) == atan(x)
def test_issue_3952():
f = sin(x)
assert integrate(f, x) == -cos(x)
raises(ValueError, lambda: integrate(f, 2*x))
def test_issue_4516():
assert integrate(2**x - 2*x, x) == 2**x/log(2) - x**2
def test_issue_7450():
ans = integrate(exp(-(1 + I)*x), (x, 0, oo))
assert re(ans) == S.Half and im(ans) == -S.Half
def test_issue_8623():
assert integrate((1 + cos(2*x)) / (3 - 2*cos(2*x)), (x, 0, pi)) == -pi/2 + sqrt(5)*pi/2
assert integrate((1 + cos(2*x))/(3 - 2*cos(2*x))) == -x/2 + sqrt(5)*(atan(sqrt(5)*tan(x)) + \
pi*floor((x - pi/2)/pi))/2
def test_issue_9569():
assert integrate(1 / (2 - cos(x)), (x, 0, pi)) == pi/sqrt(3)
assert integrate(1/(2 - cos(x))) == 2*sqrt(3)*(atan(sqrt(3)*tan(x/2)) + pi*floor((x/2 - pi/2)/pi))/3
def test_issue_13749():
assert integrate(1 / (2 + cos(x)), (x, 0, pi)) == pi/sqrt(3)
assert integrate(1/(2 + cos(x))) == 2*sqrt(3)*(atan(sqrt(3)*tan(x/2)/3) + pi*floor((x/2 - pi/2)/pi))/3
def test_matrices():
M = Matrix(2, 2, lambda i, j: (i + j + 1)*sin((i + j + 1)*x))
assert integrate(M, x) == Matrix([
[-cos(x), -cos(2*x)],
[-cos(2*x), -cos(3*x)],
])
def test_integrate_functions():
# issue 4111
assert integrate(f(x), x) == Integral(f(x), x)
assert integrate(f(x), (x, 0, 1)) == Integral(f(x), (x, 0, 1))
assert integrate(f(x)*diff(f(x), x), x) == f(x)**2/2
assert integrate(diff(f(x), x) / f(x), x) == log(f(x))
def test_integrate_derivatives():
assert integrate(Derivative(f(x), x), x) == f(x)
assert integrate(Derivative(f(y), y), x) == x*Derivative(f(y), y)
assert integrate(Derivative(f(x), x)**2, x) == \
Integral(Derivative(f(x), x)**2, x)
def test_transform():
a = Integral(x**2 + 1, (x, -1, 2))
fx = x
fy = 3*y + 1
assert a.doit() == a.transform(fx, fy).doit()
assert a.transform(fx, fy).transform(fy, fx) == a
fx = 3*x + 1
fy = y
assert a.transform(fx, fy).transform(fy, fx) == a
a = Integral(sin(1/x), (x, 0, 1))
assert a.transform(x, 1/y) == Integral(sin(y)/y**2, (y, 1, oo))
assert a.transform(x, 1/y).transform(y, 1/x) == a
a = Integral(exp(-x**2), (x, -oo, oo))
assert a.transform(x, 2*y) == Integral(2*exp(-4*y**2), (y, -oo, oo))
# < 3 arg limit handled properly
assert Integral(x, x).transform(x, a*y).doit() == \
Integral(y*a**2, y).doit()
_3 = S(3)
assert Integral(x, (x, 0, -_3)).transform(x, 1/y).doit() == \
Integral(-1/x**3, (x, -oo, -1/_3)).doit()
assert Integral(x, (x, 0, _3)).transform(x, 1/y) == \
Integral(y**(-3), (y, 1/_3, oo))
# issue 8400
i = Integral(x + y, (x, 1, 2), (y, 1, 2))
assert i.transform(x, (x + 2*y, x)).doit() == \
i.transform(x, (x + 2*z, x)).doit() == 3
def test_issue_4052():
f = S(1)/2*asin(x) + x*sqrt(1 - x**2)/2
assert integrate(cos(asin(x)), x) == f
assert integrate(sin(acos(x)), x) == f
def NS(e, n=15, **options):
return sstr(sympify(e).evalf(n, **options), full_prec=True)
@slow
def test_evalf_integrals():
assert NS(Integral(x, (x, 2, 5)), 15) == '10.5000000000000'
gauss = Integral(exp(-x**2), (x, -oo, oo))
assert NS(gauss, 15) == '1.77245385090552'
assert NS(gauss**2 - pi + E*Rational(
1, 10**20), 15) in ('2.71828182845904e-20', '2.71828182845905e-20')
# A monster of an integral from http://mathworld.wolfram.com/DefiniteIntegral.html
t = Symbol('t')
a = 8*sqrt(3)/(1 + 3*t**2)
b = 16*sqrt(2)*(3*t + 1)*sqrt(4*t**2 + t + 1)**3
c = (3*t**2 + 1)*(11*t**2 + 2*t + 3)**2
d = sqrt(2)*(249*t**2 + 54*t + 65)/(11*t**2 + 2*t + 3)**2
f = a - b/c - d
assert NS(Integral(f, (t, 0, 1)), 50) == \
NS((3*sqrt(2) - 49*pi + 162*atan(sqrt(2)))/12, 50)
# http://mathworld.wolfram.com/VardisIntegral.html
assert NS(Integral(log(log(1/x))/(1 + x + x**2), (x, 0, 1)), 15) == \
NS('pi/sqrt(3) * log(2*pi**(5/6) / gamma(1/6))', 15)
# http://mathworld.wolfram.com/AhmedsIntegral.html
assert NS(Integral(atan(sqrt(x**2 + 2))/(sqrt(x**2 + 2)*(x**2 + 1)), (x,
0, 1)), 15) == NS(5*pi**2/96, 15)
# http://mathworld.wolfram.com/AbelsIntegral.html
assert NS(Integral(x/((exp(pi*x) - exp(
-pi*x))*(x**2 + 1)), (x, 0, oo)), 15) == NS('log(2)/2-1/4', 15)
# Complex part trimming
# http://mathworld.wolfram.com/VardisIntegral.html
assert NS(Integral(log(log(sin(x)/cos(x))), (x, pi/4, pi/2)), 15, chop=True) == \
NS('pi/4*log(4*pi**3/gamma(1/4)**4)', 15)
#
# Endpoints causing trouble (rounding error in integration points -> complex log)
assert NS(
2 + Integral(log(2*cos(x/2)), (x, -pi, pi)), 17, chop=True) == NS(2, 17)
assert NS(
2 + Integral(log(2*cos(x/2)), (x, -pi, pi)), 20, chop=True) == NS(2, 20)
assert NS(
2 + Integral(log(2*cos(x/2)), (x, -pi, pi)), 22, chop=True) == NS(2, 22)
# Needs zero handling
assert NS(pi - 4*Integral(
'sqrt(1-x**2)', (x, 0, 1)), 15, maxn=30, chop=True) in ('0.0', '0')
# Oscillatory quadrature
a = Integral(sin(x)/x**2, (x, 1, oo)).evalf(maxn=15)
assert 0.49 < a < 0.51
assert NS(
Integral(sin(x)/x**2, (x, 1, oo)), quad='osc') == '0.504067061906928'
assert NS(Integral(
cos(pi*x + 1)/x, (x, -oo, -1)), quad='osc') == '0.276374705640365'
# indefinite integrals aren't evaluated
assert NS(Integral(x, x)) == 'Integral(x, x)'
assert NS(Integral(x, (x, y))) == 'Integral(x, (x, y))'
def test_evalf_issue_939():
# https://github.com/sympy/sympy/issues/4038
# The output form of an integral may differ by a step function between
# revisions, making this test a bit useless. This can't be said about
# other two tests. For now, all values of this evaluation are used here,
# but in future this should be reconsidered.
assert NS(integrate(1/(x**5 + 1), x).subs(x, 4), chop=True) in \
['-0.000976138910649103', '0.965906660135753', '1.93278945918216']
assert NS(Integral(1/(x**5 + 1), (x, 2, 4))) == '0.0144361088886740'
assert NS(
integrate(1/(x**5 + 1), (x, 2, 4)), chop=True) == '0.0144361088886740'
@XFAIL
def test_failing_integrals():
#---
# Double integrals not implemented
assert NS(Integral(
sqrt(x) + x*y, (x, 1, 2), (y, -1, 1)), 15) == '2.43790283299492'
# double integral + zero detection
assert NS(Integral(sin(x + x*y), (x, -1, 1), (y, -1, 1)), 15) == '0.0'
def test_integrate_SingularityFunction():
in_1 = SingularityFunction(x, a, 3) + SingularityFunction(x, 5, -1)
out_1 = SingularityFunction(x, a, 4)/4 + SingularityFunction(x, 5, 0)
assert integrate(in_1, x) == out_1
in_2 = 10*SingularityFunction(x, 4, 0) - 5*SingularityFunction(x, -6, -2)
out_2 = 10*SingularityFunction(x, 4, 1) - 5*SingularityFunction(x, -6, -1)
assert integrate(in_2, x) == out_2
in_3 = 2*x**2*y -10*SingularityFunction(x, -4, 7) - 2*SingularityFunction(y, 10, -2)
out_3_1 = 2*x**3*y/3 - 2*x*SingularityFunction(y, 10, -2) - 5*SingularityFunction(x, -4, 8)/4
out_3_2 = x**2*y**2 - 10*y*SingularityFunction(x, -4, 7) - 2*SingularityFunction(y, 10, -1)
assert integrate(in_3, x) == out_3_1
assert integrate(in_3, y) == out_3_2
assert Integral(in_3, x) == Integral(in_3, x)
assert Integral(in_3, x).doit() == out_3_1
in_4 = 10*SingularityFunction(x, -4, 7) - 2*SingularityFunction(x, 10, -2)
out_4 = 5*SingularityFunction(x, -4, 8)/4 - 2*SingularityFunction(x, 10, -1)
assert integrate(in_4, (x, -oo, x)) == out_4
assert integrate(SingularityFunction(x, 5, -1), x) == SingularityFunction(x, 5, 0)
assert integrate(SingularityFunction(x, 0, -1), (x, -oo, oo)) == 1
assert integrate(5*SingularityFunction(x, 5, -1), (x, -oo, oo)) == 5
assert integrate(SingularityFunction(x, 5, -1) * f(x), (x, -oo, oo)) == f(5)
def test_integrate_DiracDelta():
# This is here to check that deltaintegrate is being called, but also
# to test definite integrals. More tests are in test_deltafunctions.py
assert integrate(DiracDelta(x) * f(x), (x, -oo, oo)) == f(0)
assert integrate(DiracDelta(x)**2, (x, -oo, oo)) == DiracDelta(0)
# issue 4522
assert integrate(integrate((4 - 4*x + x*y - 4*y) * \
DiracDelta(x)*DiracDelta(y - 1), (x, 0, 1)), (y, 0, 1)) == 0
# issue 5729
p = exp(-(x**2 + y**2))/pi
assert integrate(p*DiracDelta(x - 10*y), (x, -oo, oo), (y, -oo, oo)) == \
integrate(p*DiracDelta(x - 10*y), (y, -oo, oo), (x, -oo, oo)) == \
integrate(p*DiracDelta(10*x - y), (x, -oo, oo), (y, -oo, oo)) == \
integrate(p*DiracDelta(10*x - y), (y, -oo, oo), (x, -oo, oo)) == \
1/sqrt(101*pi)
@XFAIL
def test_integrate_DiracDelta_fails():
# issue 6427
assert integrate(integrate(integrate(
DiracDelta(x - y - z), (z, 0, oo)), (y, 0, 1)), (x, 0, 1)) == S(1)/2
def test_integrate_returns_piecewise():
assert integrate(x**y, x) == Piecewise(
(x**(y + 1)/(y + 1), Ne(y, -1)), (log(x), True))
assert integrate(x**y, y) == Piecewise(
(x**y/log(x), Ne(log(x), 0)), (y, True))
assert integrate(exp(n*x), x) == Piecewise(
(exp(n*x)/n, Ne(n, 0)), (x, True))
assert integrate(x*exp(n*x), x) == Piecewise(
((n*x - 1)*exp(n*x)/n**2, Ne(n**2, 0)), (x**2/2, True))
assert integrate(x**(n*y), x) == Piecewise(
(x**(n*y + 1)/(n*y + 1), Ne(n*y, -1)), (log(x), True))
assert integrate(x**(n*y), y) == Piecewise(
(x**(n*y)/(n*log(x)), Ne(n*log(x), 0)), (y, True))
assert integrate(cos(n*x), x) == Piecewise(
(sin(n*x)/n, Ne(n, 0)), (x, True))
assert integrate(cos(n*x)**2, x) == Piecewise(
((n*x/2 + sin(n*x)*cos(n*x)/2)/n, Ne(n, 0)), (x, True))
assert integrate(x*cos(n*x), x) == Piecewise(
(x*sin(n*x)/n + cos(n*x)/n**2, Ne(n, 0)), (x**2/2, True))
assert integrate(sin(n*x), x) == Piecewise(
(-cos(n*x)/n, Ne(n, 0)), (0, True))
assert integrate(sin(n*x)**2, x) == Piecewise(
((n*x/2 - sin(n*x)*cos(n*x)/2)/n, Ne(n, 0)), (0, True))
assert integrate(x*sin(n*x), x) == Piecewise(
(-x*cos(n*x)/n + sin(n*x)/n**2, Ne(n, 0)), (0, True))
assert integrate(exp(x*y), (x, 0, z)) == Piecewise(
(exp(y*z)/y - 1/y, (y > -oo) & (y < oo) & Ne(y, 0)), (z, True))
def test_integrate_max_min():
x = symbols('x', real=True)
assert integrate(Min(x, 2), (x, 0, 3)) == 4
assert integrate(Max(x**2, x**3), (x, 0, 2)) == S(49)/12
assert integrate(Min(exp(x), exp(-x))**2, x) == Piecewise( \
(exp(2*x)/2, x <= 0), (1 - exp(-2*x)/2, True))
# issue 7907
c = symbols('c', real=True)
int1 = integrate(Max(c, x)*exp(-x**2), (x, -oo, oo))
int2 = integrate(c*exp(-x**2), (x, -oo, c))
int3 = integrate(x*exp(-x**2), (x, c, oo))
assert int1 == int2 + int3 == sqrt(pi)*c*erf(c)/2 + \
sqrt(pi)*c/2 + exp(-c**2)/2
def test_integrate_Abs_sign():
assert integrate(Abs(x), (x, -2, 1)) == S(5)/2
assert integrate(Abs(x), (x, 0, 1)) == S(1)/2
assert integrate(Abs(x + 1), (x, 0, 1)) == S(3)/2
assert integrate(Abs(x**2 - 1), (x, -2, 2)) == 4
assert integrate(Abs(x**2 - 3*x), (x, -15, 15)) == 2259
assert integrate(sign(x), (x, -1, 2)) == 1
assert integrate(sign(x)*sin(x), (x, -pi, pi)) == 4
assert integrate(sign(x - 2) * x**2, (x, 0, 3)) == S(11)/3
t, s = symbols('t s', real=True)
assert integrate(Abs(t), t) == Piecewise(
(-t**2/2, t <= 0), (t**2/2, True))
assert integrate(Abs(2*t - 6), t) == Piecewise(
(-t**2 + 6*t, t <= 3), (t**2 - 6*t + 18, True))
assert (integrate(abs(t - s**2), (t, 0, 2)) ==
2*s**2*Min(2, s**2) - 2*s**2 - Min(2, s**2)**2 + 2)
assert integrate(exp(-Abs(t)), t) == Piecewise(
(exp(t), t <= 0), (2 - exp(-t), True))
assert integrate(sign(2*t - 6), t) == Piecewise(
(-t, t < 3), (t - 6, True))
assert integrate(2*t*sign(t**2 - 1), t) == Piecewise(
(t**2, t < -1), (-t**2 + 2, t < 1), (t**2, True))
assert integrate(sign(t), (t, s + 1)) == Piecewise(
(s + 1, s + 1 > 0), (-s - 1, s + 1 < 0), (0, True))
def test_subs1():
e = Integral(exp(x - y), x)
assert e.subs(y, 3) == Integral(exp(x - 3), x)
e = Integral(exp(x - y), (x, 0, 1))
assert e.subs(y, 3) == Integral(exp(x - 3), (x, 0, 1))
f = Lambda(x, exp(-x**2))
conv = Integral(f(x - y)*f(y), (y, -oo, oo))
assert conv.subs({x: 0}) == Integral(exp(-2*y**2), (y, -oo, oo))
def test_subs2():
e = Integral(exp(x - y), x, t)
assert e.subs(y, 3) == Integral(exp(x - 3), x, t)
e = Integral(exp(x - y), (x, 0, 1), (t, 0, 1))
assert e.subs(y, 3) == Integral(exp(x - 3), (x, 0, 1), (t, 0, 1))
f = Lambda(x, exp(-x**2))
conv = Integral(f(x - y)*f(y), (y, -oo, oo), (t, 0, 1))
assert conv.subs({x: 0}) == Integral(exp(-2*y**2), (y, -oo, oo), (t, 0, 1))
def test_subs3():
e = Integral(exp(x - y), (x, 0, y), (t, y, 1))
assert e.subs(y, 3) == Integral(exp(x - 3), (x, 0, 3), (t, 3, 1))
f = Lambda(x, exp(-x**2))
conv = Integral(f(x - y)*f(y), (y, -oo, oo), (t, x, 1))
assert conv.subs({x: 0}) == Integral(exp(-2*y**2), (y, -oo, oo), (t, 0, 1))
def test_subs4():
e = Integral(exp(x), (x, 0, y), (t, y, 1))
assert e.subs(y, 3) == Integral(exp(x), (x, 0, 3), (t, 3, 1))
f = Lambda(x, exp(-x**2))
conv = Integral(f(y)*f(y), (y, -oo, oo), (t, x, 1))
assert conv.subs({x: 0}) == Integral(exp(-2*y**2), (y, -oo, oo), (t, 0, 1))
def test_subs5():
e = Integral(exp(-x**2), (x, -oo, oo))
assert e.subs(x, 5) == e
e = Integral(exp(-x**2 + y), x)
assert e.subs(y, 5) == Integral(exp(-x**2 + 5), x)
e = Integral(exp(-x**2 + y), (x, x))
assert e.subs(x, 5) == Integral(exp(y - x**2), (x, 5))
assert e.subs(y, 5) == Integral(exp(-x**2 + 5), x)
e = Integral(exp(-x**2 + y), (y, -oo, oo), (x, -oo, oo))
assert e.subs(x, 5) == e
assert e.subs(y, 5) == e
# Test evaluation of antiderivatives
e = Integral(exp(-x**2), (x, x))
assert e.subs(x, 5) == Integral(exp(-x**2), (x, 5))
e = Integral(exp(x), x)
assert (e.subs(x,1) - e.subs(x,0) - Integral(exp(x), (x, 0, 1))
).doit().is_zero
def test_subs6():
a, b = symbols('a b')
e = Integral(x*y, (x, f(x), f(y)))
assert e.subs(x, 1) == Integral(x*y, (x, f(1), f(y)))
assert e.subs(y, 1) == Integral(x, (x, f(x), f(1)))
e = Integral(x*y, (x, f(x), f(y)), (y, f(x), f(y)))
assert e.subs(x, 1) == Integral(x*y, (x, f(1), f(y)), (y, f(1), f(y)))
assert e.subs(y, 1) == Integral(x*y, (x, f(x), f(y)), (y, f(x), f(1)))
e = Integral(x*y, (x, f(x), f(a)), (y, f(x), f(a)))
assert e.subs(a, 1) == Integral(x*y, (x, f(x), f(1)), (y, f(x), f(1)))
def test_subs7():
e = Integral(x, (x, 1, y), (y, 1, 2))
assert e.subs({x: 1, y: 2}) == e
e = Integral(sin(x) + sin(y), (x, sin(x), sin(y)),
(y, 1, 2))
assert e.subs(sin(y), 1) == e
assert e.subs(sin(x), 1) == Integral(sin(x) + sin(y), (x, 1, sin(y)),
(y, 1, 2))
def test_expand():
e = Integral(f(x)+f(x**2), (x, 1, y))
assert e.expand() == Integral(f(x), (x, 1, y)) + Integral(f(x**2), (x, 1, y))
def test_integration_variable():
raises(ValueError, lambda: Integral(exp(-x**2), 3))
raises(ValueError, lambda: Integral(exp(-x**2), (3, -oo, oo)))
def test_expand_integral():
assert Integral(cos(x**2)*(sin(x**2) + 1), (x, 0, 1)).expand() == \
Integral(cos(x**2)*sin(x**2), (x, 0, 1)) + \
Integral(cos(x**2), (x, 0, 1))
assert Integral(cos(x**2)*(sin(x**2) + 1), x).expand() == \
Integral(cos(x**2)*sin(x**2), x) + \
Integral(cos(x**2), x)
def test_as_sum_midpoint1():
e = Integral(sqrt(x**3 + 1), (x, 2, 10))
assert e.as_sum(1, method="midpoint") == 8*sqrt(217)
assert e.as_sum(2, method="midpoint") == 4*sqrt(65) + 12*sqrt(57)
assert e.as_sum(3, method="midpoint") == 8*sqrt(217)/3 + \
8*sqrt(3081)/27 + 8*sqrt(52809)/27
assert e.as_sum(4, method="midpoint") == 2*sqrt(730) + \
4*sqrt(7) + 4*sqrt(86) + 6*sqrt(14)
assert abs(e.as_sum(4, method="midpoint").n() - e.n()) < 0.5
e = Integral(sqrt(x**3 + y**3), (x, 2, 10), (y, 0, 10))
raises(NotImplementedError, lambda: e.as_sum(4))
def test_as_sum_midpoint2():
e = Integral((x + y)**2, (x, 0, 1))
n = Symbol('n', positive=True, integer=True)
assert e.as_sum(1, method="midpoint").expand() == S(1)/4 + y + y**2
assert e.as_sum(2, method="midpoint").expand() == S(5)/16 + y + y**2
assert e.as_sum(3, method="midpoint").expand() == S(35)/108 + y + y**2
assert e.as_sum(4, method="midpoint").expand() == S(21)/64 + y + y**2
assert e.as_sum(n, method="midpoint").expand() == \
y**2 + y + S(1)/3 - 1/(12*n**2)
def test_as_sum_left():
e = Integral((x + y)**2, (x, 0, 1))
assert e.as_sum(1, method="left").expand() == y**2
assert e.as_sum(2, method="left").expand() == S(1)/8 + y/2 + y**2
assert e.as_sum(3, method="left").expand() == S(5)/27 + 2*y/3 + y**2
assert e.as_sum(4, method="left").expand() == S(7)/32 + 3*y/4 + y**2
assert e.as_sum(n, method="left").expand() == \
y**2 + y + S(1)/3 - y/n - 1/(2*n) + 1/(6*n**2)
assert e.as_sum(10, method="left", evaluate=False).has(Sum)
def test_as_sum_right():
e = Integral((x + y)**2, (x, 0, 1))
assert e.as_sum(1, method="right").expand() == 1 + 2*y + y**2
assert e.as_sum(2, method="right").expand() == S(5)/8 + 3*y/2 + y**2
assert e.as_sum(3, method="right").expand() == S(14)/27 + 4*y/3 + y**2
assert e.as_sum(4, method="right").expand() == S(15)/32 + 5*y/4 + y**2
assert e.as_sum(n, method="right").expand() == \
y**2 + y + S(1)/3 + y/n + 1/(2*n) + 1/(6*n**2)
def test_as_sum_trapezoid():
e = Integral((x + y)**2, (x, 0, 1))
assert e.as_sum(1, method="trapezoid").expand() == y**2 + y + S(1)/2
assert e.as_sum(2, method="trapezoid").expand() == y**2 + y + S(3)/8
assert e.as_sum(3, method="trapezoid").expand() == y**2 + y + S(19)/54
assert e.as_sum(4, method="trapezoid").expand() == y**2 + y + S(11)/32
assert e.as_sum(n, method="trapezoid").expand() == \
y**2 + y + S(1)/3 + 1/(6*n**2)
assert Integral(sign(x), (x, 0, 1)).as_sum(1, 'trapezoid') == S(1)/2
def test_as_sum_raises():
e = Integral((x + y)**2, (x, 0, 1))
raises(ValueError, lambda: e.as_sum(-1))
raises(ValueError, lambda: e.as_sum(0))
raises(ValueError, lambda: Integral(x).as_sum(3))
raises(ValueError, lambda: e.as_sum(oo))
raises(ValueError, lambda: e.as_sum(3, method='xxxx2'))
def test_nested_doit():
e = Integral(Integral(x, x), x)
f = Integral(x, x, x)
assert e.doit() == f.doit()
def test_issue_4665():
# Allow only upper or lower limit evaluation
e = Integral(x**2, (x, None, 1))
f = Integral(x**2, (x, 1, None))
assert e.doit() == Rational(1, 3)
assert f.doit() == Rational(-1, 3)
assert Integral(x*y, (x, None, y)).subs(y, t) == Integral(x*t, (x, None, t))
assert Integral(x*y, (x, y, None)).subs(y, t) == Integral(x*t, (x, t, None))
assert integrate(x**2, (x, None, 1)) == Rational(1, 3)
assert integrate(x**2, (x, 1, None)) == Rational(-1, 3)
assert integrate("x**2", ("x", "1", None)) == Rational(-1, 3)
def test_integral_reconstruct():
e = Integral(x**2, (x, -1, 1))
assert e == Integral(*e.args)
def test_doit_integrals():
e = Integral(Integral(2*x), (x, 0, 1))
assert e.doit() == Rational(1, 3)
assert e.doit(deep=False) == Rational(1, 3)
f = Function('f')
# doesn't matter if the integral can't be performed
assert Integral(f(x), (x, 1, 1)).doit() == 0
# doesn't matter if the limits can't be evaluated
assert Integral(0, (x, 1, Integral(f(x), x))).doit() == 0
assert Integral(x, (a, 0)).doit() == 0
limits = ((a, 1, exp(x)), (x, 0))
assert Integral(a, *limits).doit() == S(1)/4
assert Integral(a, *list(reversed(limits))).doit() == 0
def test_issue_4884():
assert integrate(sqrt(x)*(1 + x)) == \
Piecewise(
(2*sqrt(x)*(x + 1)**2/5 - 2*sqrt(x)*(x + 1)/15 - 4*sqrt(x)/15,
Abs(x + 1) > 1),
(2*I*sqrt(-x)*(x + 1)**2/5 - 2*I*sqrt(-x)*(x + 1)/15 -
4*I*sqrt(-x)/15, True))
assert integrate(x**x*(1 + log(x))) == x**x
def test_is_number():
from sympy.abc import x, y, z
from sympy import cos, sin
assert Integral(x).is_number is False
assert Integral(1, x).is_number is False
assert Integral(1, (x, 1)).is_number is True
assert Integral(1, (x, 1, 2)).is_number is True
assert Integral(1, (x, 1, y)).is_number is False
assert Integral(1, (x, y)).is_number is False
assert Integral(x, y).is_number is False
assert Integral(x, (y, 1, x)).is_number is False
assert Integral(x, (y, 1, 2)).is_number is False
assert Integral(x, (x, 1, 2)).is_number is True
# `foo.is_number` should always be equivalent to `not foo.free_symbols`
# in each of these cases, there are pseudo-free symbols
i = Integral(x, (y, 1, 1))
assert i.is_number is False and i.n() == 0
i = Integral(x, (y, z, z))
assert i.is_number is False and i.n() == 0
i = Integral(1, (y, z, z + 2))
assert i.is_number is False and i.n() == 2
assert Integral(x*y, (x, 1, 2), (y, 1, 3)).is_number is True
assert Integral(x*y, (x, 1, 2), (y, 1, z)).is_number is False
assert Integral(x, (x, 1)).is_number is True
assert Integral(x, (x, 1, Integral(y, (y, 1, 2)))).is_number is True
assert Integral(Sum(z, (z, 1, 2)), (x, 1, 2)).is_number is True
# it is possible to get a false negative if the integrand is
# actually an unsimplified zero, but this is true of is_number in general.
assert Integral(sin(x)**2 + cos(x)**2 - 1, x).is_number is False
assert Integral(f(x), (x, 0, 1)).is_number is True
def test_symbols():
from sympy.abc import x, y, z
assert Integral(0, x).free_symbols == {x}
assert Integral(x).free_symbols == {x}
assert Integral(x, (x, None, y)).free_symbols == {y}
assert Integral(x, (x, y, None)).free_symbols == {y}
assert Integral(x, (x, 1, y)).free_symbols == {y}
assert Integral(x, (x, y, 1)).free_symbols == {y}
assert Integral(x, (x, x, y)).free_symbols == {x, y}
assert Integral(x, x, y).free_symbols == {x, y}
assert Integral(x, (x, 1, 2)).free_symbols == set()
assert Integral(x, (y, 1, 2)).free_symbols == {x}
# pseudo-free in this case
assert Integral(x, (y, z, z)).free_symbols == {x, z}
assert Integral(x, (y, 1, 2), (y, None, None)).free_symbols == {x, y}
assert Integral(x, (y, 1, 2), (x, 1, y)).free_symbols == {y}
assert Integral(2, (y, 1, 2), (y, 1, x), (x, 1, 2)).free_symbols == set()
assert Integral(2, (y, x, 2), (y, 1, x), (x, 1, 2)).free_symbols == set()
assert Integral(2, (x, 1, 2), (y, x, 2), (y, 1, 2)).free_symbols == \
{x}
def test_is_zero():
from sympy.abc import x, m
assert Integral(0, (x, 1, x)).is_zero
assert Integral(1, (x, 1, 1)).is_zero
assert Integral(1, (x, 1, 2), (y, 2)).is_zero is False
assert Integral(x, (m, 0)).is_zero
assert Integral(x + m, (m, 0)).is_zero is None
i = Integral(m, (m, 1, exp(x)), (x, 0))
assert i.is_zero is None
assert Integral(m, (x, 0), (m, 1, exp(x))).is_zero is True
assert Integral(x, (x, oo, oo)).is_zero # issue 8171
assert Integral(x, (x, -oo, -oo)).is_zero
# this is zero but is beyond the scope of what is_zero
# should be doing
assert Integral(sin(x), (x, 0, 2*pi)).is_zero is None
def test_series():
from sympy.abc import x
i = Integral(cos(x), (x, x))
e = i.lseries(x)
assert i.nseries(x, n=8).removeO() == Add(*[next(e) for j in range(4)])
def test_trig_nonelementary_integrals():
x = Symbol('x')
assert integrate((1 + sin(x))/x, x) == log(x) + Si(x)
# next one comes out as log(x) + log(x**2)/2 + Ci(x)
# so not hardcoding this log ugliness
assert integrate((cos(x) + 2)/x, x).has(Ci)
def test_issue_4403():
x = Symbol('x')
y = Symbol('y')
z = Symbol('z', positive=True)
assert integrate(sqrt(x**2 + z**2), x) == \
z**2*asinh(x/z)/2 + x*sqrt(x**2 + z**2)/2
assert integrate(sqrt(x**2 - z**2), x) == \
-z**2*acosh(x/z)/2 + x*sqrt(x**2 - z**2)/2
x = Symbol('x', real=True)
y = Symbol('y', positive=True)
assert integrate(1/(x**2 + y**2)**S('3/2'), x) == \
x/(y**2*sqrt(x**2 + y**2))
# If y is real and nonzero, we get x*Abs(y)/(y**3*sqrt(x**2 + y**2)),
# which results from sqrt(1 + x**2/y**2) = sqrt(x**2 + y**2)/|y|.
def test_issue_4403_2():
assert integrate(sqrt(-x**2 - 4), x) == \
-2*atan(x/sqrt(-4 - x**2)) + x*sqrt(-4 - x**2)/2
def test_issue_4100():
R = Symbol('R', positive=True)
assert integrate(sqrt(R**2 - x**2), (x, 0, R)) == pi*R**2/4
def test_issue_5167():
from sympy.abc import w, x, y, z
f = Function('f')
assert Integral(Integral(f(x), x), x) == Integral(f(x), x, x)
assert Integral(f(x)).args == (f(x), Tuple(x))
assert Integral(Integral(f(x))).args == (f(x), Tuple(x), Tuple(x))
assert Integral(Integral(f(x)), y).args == (f(x), Tuple(x), Tuple(y))
assert Integral(Integral(f(x), z), y).args == (f(x), Tuple(z), Tuple(y))
assert Integral(Integral(Integral(f(x), x), y), z).args == \
(f(x), Tuple(x), Tuple(y), Tuple(z))
assert integrate(Integral(f(x), x), x) == Integral(f(x), x, x)
assert integrate(Integral(f(x), y), x) == y*Integral(f(x), x)
assert integrate(Integral(f(x), x), y) in [Integral(y*f(x), x), y*Integral(f(x), x)]
assert integrate(Integral(2, x), x) == x**2
assert integrate(Integral(2, x), y) == 2*x*y
# don't re-order given limits
assert Integral(1, x, y).args != Integral(1, y, x).args
# do as many as possible
assert Integral(f(x), y, x, y, x).doit() == y**2*Integral(f(x), x, x)/2
assert Integral(f(x), (x, 1, 2), (w, 1, x), (z, 1, y)).doit() == \
y*(x - 1)*Integral(f(x), (x, 1, 2)) - (x - 1)*Integral(f(x), (x, 1, 2))
def test_issue_4890():
z = Symbol('z', positive=True)
assert integrate(exp(-log(x)**2), x) == \
sqrt(pi)*exp(S(1)/4)*erf(log(x)-S(1)/2)/2
assert integrate(exp(log(x)**2), x) == \
sqrt(pi)*exp(-S(1)/4)*erfi(log(x)+S(1)/2)/2
assert integrate(exp(-z*log(x)**2), x) == \
sqrt(pi)*exp(1/(4*z))*erf(sqrt(z)*log(x) - 1/(2*sqrt(z)))/(2*sqrt(z))
def test_issue_4376():
n = Symbol('n', integer=True, positive=True)
assert simplify(integrate(n*(x**(1/n) - 1), (x, 0, S.Half)) -
(n**2 - 2**(1/n)*n**2 - n*2**(1/n))/(2**(1 + 1/n) + n*2**(1 + 1/n))) == 0
def test_issue_4517():
assert integrate((sqrt(x) - x**3)/x**Rational(1, 3), x) == \
6*x**Rational(7, 6)/7 - 3*x**Rational(11, 3)/11
def test_issue_4527():
k, m = symbols('k m', integer=True)
ans = integrate(sin(k*x)*sin(m*x), (x, 0, pi)
).simplify() == Piecewise(
(0, Eq(k, 0) | Eq(m, 0)),
(-pi/2, Eq(k, -m)),
(pi/2, Eq(k, m)),
(0, True))
assert integrate(sin(k*x)*sin(m*x), (x,)) == Piecewise(
(0, And(Eq(k, 0), Eq(m, 0))),
(-x*sin(m*x)**2/2 - x*cos(m*x)**2/2 + sin(m*x)*cos(m*x)/(2*m), Eq(k, -m)),
(x*sin(m*x)**2/2 + x*cos(m*x)**2/2 - sin(m*x)*cos(m*x)/(2*m), Eq(k, m)),
(m*sin(k*x)*cos(m*x)/(k**2 - m**2) -
k*sin(m*x)*cos(k*x)/(k**2 - m**2), True))
def test_issue_4199():
ypos = Symbol('y', positive=True)
# TODO: Remove conds='none' below, let the assumption take care of it.
assert integrate(exp(-I*2*pi*ypos*x)*x, (x, -oo, oo), conds='none') == \
Integral(exp(-I*2*pi*ypos*x)*x, (x, -oo, oo))
@slow
def test_issue_3940():
a, b, c, d = symbols('a:d', positive=True, finite=True)
assert integrate(exp(-x**2 + I*c*x), x) == \
-sqrt(pi)*exp(-c**2/4)*erf(I*c/2 - x)/2
assert integrate(exp(a*x**2 + b*x + c), x) == \
sqrt(pi)*exp(c)*exp(-b**2/(4*a))*erfi(sqrt(a)*x + b/(2*sqrt(a)))/(2*sqrt(a))
from sympy import expand_mul
from sympy.abc import k
assert expand_mul(integrate(exp(-x**2)*exp(I*k*x), (x, -oo, oo))) == \
sqrt(pi)*exp(-k**2/4)
a, d = symbols('a d', positive=True)
assert expand_mul(integrate(exp(-a*x**2 + 2*d*x), (x, -oo, oo))) == \
sqrt(pi)*exp(d**2/a)/sqrt(a)
def test_issue_5413():
# Note that this is not the same as testing ratint() because integrate()
# pulls out the coefficient.
assert integrate(-a/(a**2 + x**2), x) == I*log(-I*a + x)/2 - I*log(I*a + x)/2
def test_issue_4892a():
A, z = symbols('A z')
c = Symbol('c', nonzero=True)
P1 = -A*exp(-z)
P2 = -A/(c*t)*(sin(x)**2 + cos(y)**2)
h1 = -sin(x)**2 - cos(y)**2
h2 = -sin(x)**2 + sin(y)**2 - 1
# there is still some non-deterministic behavior in integrate
# or trigsimp which permits one of the following
assert integrate(c*(P2 - P1), t) in [
c*(-A*(-h1)*log(c*t)/c + A*t*exp(-z)),
c*(-A*(-h2)*log(c*t)/c + A*t*exp(-z)),
c*( A* h1 *log(c*t)/c + A*t*exp(-z)),
c*( A* h2 *log(c*t)/c + A*t*exp(-z)),
(A*c*t - A*(-h1)*log(t)*exp(z))*exp(-z),
(A*c*t - A*(-h2)*log(t)*exp(z))*exp(-z),
]
def test_issue_4892b():
# Issues relating to issue 4596 are making the actual result of this hard
# to test. The answer should be something like
#
# (-sin(y) + sqrt(-72 + 48*cos(y) - 8*cos(y)**2)/2)*log(x + sqrt(-72 +
# 48*cos(y) - 8*cos(y)**2)/(2*(3 - cos(y)))) + (-sin(y) - sqrt(-72 +
# 48*cos(y) - 8*cos(y)**2)/2)*log(x - sqrt(-72 + 48*cos(y) -
# 8*cos(y)**2)/(2*(3 - cos(y)))) + x**2*sin(y)/2 + 2*x*cos(y)
expr = (sin(y)*x**3 + 2*cos(y)*x**2 + 12)/(x**2 + 2)
assert trigsimp(factor(integrate(expr, x).diff(x) - expr)) == 0
def test_issue_5178():
assert integrate(sin(x)*f(y, z), (x, 0, pi), (y, 0, pi), (z, 0, pi)) == \
2*Integral(f(y, z), (y, 0, pi), (z, 0, pi))
def test_integrate_series():
f = sin(x).series(x, 0, 10)
g = x**2/2 - x**4/24 + x**6/720 - x**8/40320 + x**10/3628800 + O(x**11)
assert integrate(f, x) == g
assert diff(integrate(f, x), x) == f
assert integrate(O(x**5), x) == O(x**6)
def test_atom_bug():
from sympy import meijerg
from sympy.integrals.heurisch import heurisch
assert heurisch(meijerg([], [], [1], [], x), x) is None
def test_limit_bug():
z = Symbol('z', zero=False)
assert integrate(sin(x*y*z), (x, 0, pi), (y, 0, pi)) == \
(log(z**2) + 2*EulerGamma + 2*log(pi))/(2*z) - \
(-log(pi*z) + log(pi**2*z**2)/2 + Ci(pi**2*z))/z + log(pi)/z
def test_issue_4703():
g = Function('g')
assert integrate(exp(x)*g(x), x).has(Integral)
def test_issue_1888():
f = Function('f')
assert integrate(f(x).diff(x)**2, x).has(Integral)
# The following tests work using meijerint.
def test_issue_3558():
from sympy import Si
assert integrate(cos(x*y), (x, -pi/2, pi/2), (y, 0, pi)) == 2*Si(pi**2/2)
def test_issue_4422():
assert integrate(1/sqrt(16 + 4*x**2), x) == asinh(x/2) / 2
def test_issue_4493():
from sympy import simplify
assert simplify(integrate(x*sqrt(1 + 2*x), x)) == \
sqrt(2*x + 1)*(6*x**2 + x - 1)/15
def test_issue_4737():
assert integrate(sin(x)/x, (x, -oo, oo)) == pi
assert integrate(sin(x)/x, (x, 0, oo)) == pi/2
def test_issue_4992():
# Note: psi in _check_antecedents becomes NaN.
from sympy import simplify, expand_func, polygamma, gamma
a = Symbol('a', positive=True)
assert simplify(expand_func(integrate(exp(-x)*log(x)*x**a, (x, 0, oo)))) == \
(a*polygamma(0, a) + 1)*gamma(a)
def test_issue_4487():
from sympy import lowergamma, simplify
assert simplify(integrate(exp(-x)*x**y, x)) == lowergamma(y + 1, x)
def test_issue_4215():
x = Symbol("x")
assert integrate(1/(x**2), (x, -1, 1)) == oo
def test_issue_4400():
n = Symbol('n', integer=True, positive=True)
assert integrate((x**n)*log(x), x) == \
n*x*x**n*log(x)/(n**2 + 2*n + 1) + x*x**n*log(x)/(n**2 + 2*n + 1) - \
x*x**n/(n**2 + 2*n + 1)
def test_issue_6253():
# Note: this used to raise NotImplementedError
# Note: psi in _check_antecedents becomes NaN.
assert integrate((sqrt(1 - x) + sqrt(1 + x))**2/x, x, meijerg=True) == \
Integral((sqrt(-x + 1) + sqrt(x + 1))**2/x, x)
def test_issue_4153():
assert integrate(1/(1 + x + y + z), (x, 0, 1), (y, 0, 1), (z, 0, 1)) in [
-12*log(3) - 3*log(6)/2 + 3*log(8)/2 + 5*log(2) + 7*log(4),
6*log(2) + 8*log(4) - 27*log(3)/2, 22*log(2) - 27*log(3)/2,
-12*log(3) - 3*log(6)/2 + 47*log(2)/2]
def test_issue_4326():
R, b, h = symbols('R b h')
# It doesn't matter if we can do the integral. Just make sure the result
# doesn't contain nan. This is really a test against _eval_interval.
assert not integrate(((h*(x - R + b))/b)*sqrt(R**2 - x**2), (x, R - b, R)).has(nan)
def test_powers():
assert integrate(2**x + 3**x, x) == 2**x/log(2) + 3**x/log(3)
def test_manual_option():
raises(ValueError, lambda: integrate(1/x, x, manual=True, meijerg=True))
# an example of a function that manual integration cannot handle
assert integrate(log(1+x)/x, (x, 0, 1), manual=True).has(Integral)
def test_meijerg_option():
raises(ValueError, lambda: integrate(1/x, x, meijerg=True, risch=True))
# an example of a function that meijerg integration cannot handle
assert integrate(tan(x), x, meijerg=True) == Integral(tan(x), x)
def test_risch_option():
# risch=True only allowed on indefinite integrals
raises(ValueError, lambda: integrate(1/log(x), (x, 0, oo), risch=True))
assert integrate(exp(-x**2), x, risch=True) == NonElementaryIntegral(exp(-x**2), x)
assert integrate(log(1/x)*y, x, y, risch=True) == y**2*(x*log(1/x)/2 + x/2)
assert integrate(erf(x), x, risch=True) == Integral(erf(x), x)
# TODO: How to test risch=False?
def test_heurisch_option():
raises(ValueError, lambda: integrate(1/x, x, risch=True, heurisch=True))
# an integral that heurisch can handle
assert integrate(exp(x**2), x, heurisch=True) == sqrt(pi)*erfi(x)/2
# an integral that heurisch currently cannot handle
assert integrate(exp(x)/x, x, heurisch=True) == Integral(exp(x)/x, x)
# an integral where heurisch currently hangs, issue 15471
assert integrate(log(x)*cos(log(x))/x**(S(3)/4), x, heurisch=False) == (
-128*x**(S(1)/4)*sin(log(x))/289 + 240*x**(S(1)/4)*cos(log(x))/289 +
(16*x**(S(1)/4)*sin(log(x))/17 + 4*x**(S(1)/4)*cos(log(x))/17)*log(x))
def test_issue_6828():
f = 1/(1.08*x**2 - 4.3)
g = integrate(f, x).diff(x)
assert verify_numerically(f, g, tol=1e-12)
@XFAIL
def test_integrate_Piecewise_rational_over_reals():
f = Piecewise(
(0, t - 478.515625*pi < 0),
(13.2075145209219*pi/(0.000871222*t + 0.995)**2, t - 478.515625*pi >= 0))
assert integrate(f, (t, 0, oo)) == 15235.9375*pi
def test_issue_4803():
x_max = Symbol("x_max")
assert integrate(y/pi*exp(-(x_max - x)/cos(a)), x) == \
y*exp((x - x_max)/cos(a))*cos(a)/pi
def test_issue_4234():
assert integrate(1/sqrt(1 + tan(x)**2)) == tan(x)/sqrt(1 + tan(x)**2)
def test_issue_4492():
assert simplify(integrate(x**2 * sqrt(5 - x**2), x)) == Piecewise(
(I*(2*x**5 - 15*x**3 + 25*x - 25*sqrt(x**2 - 5)*acosh(sqrt(5)*x/5)) /
(8*sqrt(x**2 - 5)), 1 < Abs(x**2)/5),
((-2*x**5 + 15*x**3 - 25*x + 25*sqrt(-x**2 + 5)*asin(sqrt(5)*x/5)) /
(8*sqrt(-x**2 + 5)), True))
def test_issue_2708():
# This test needs to use an integration function that can
# not be evaluated in closed form. Update as needed.
f = 1/(a + z + log(z))
integral_f = NonElementaryIntegral(f, (z, 2, 3))
assert Integral(f, (z, 2, 3)).doit() == integral_f
assert integrate(f + exp(z), (z, 2, 3)) == integral_f - exp(2) + exp(3)
assert integrate(2*f + exp(z), (z, 2, 3)) == \
2*integral_f - exp(2) + exp(3)
assert integrate(exp(1.2*n*s*z*(-t + z)/t), (z, 0, x)) == \
NonElementaryIntegral(exp(-1.2*n*s*z)*exp(1.2*n*s*z**2/t),
(z, 0, x))
def test_issue_8368():
assert integrate(exp(-s*x)*cosh(x), (x, 0, oo)) == \
Piecewise(
( pi*Piecewise(
( -s/(pi*(-s**2 + 1)),
Abs(s**2) < 1),
( 1/(pi*s*(1 - 1/s**2)),
Abs(s**(-2)) < 1),
( meijerg(
((S(1)/2,), (0, 0)),
((0, S(1)/2), (0,)),
polar_lift(s)**2),
True)
),
And(
Abs(periodic_argument(polar_lift(s)**2, oo)) < pi,
cos(Abs(periodic_argument(polar_lift(s)**2, oo))/2)*sqrt(Abs(s**2)) - 1 > 0,
Ne(s**2, 1))
),
(
Integral(exp(-s*x)*cosh(x), (x, 0, oo)),
True))
assert integrate(exp(-s*x)*sinh(x), (x, 0, oo)) == \
Piecewise(
( -1/(s + 1)/2 - 1/(-s + 1)/2,
And(
Ne(1/s, 1),
Abs(periodic_argument(s, oo)) < pi/2,
Abs(periodic_argument(s, oo)) <= pi/2,
cos(Abs(periodic_argument(s, oo)))*Abs(s) - 1 > 0)),
( Integral(exp(-s*x)*sinh(x), (x, 0, oo)),
True))
def test_issue_8901():
assert integrate(sinh(1.0*x)) == 1.0*cosh(1.0*x)
assert integrate(tanh(1.0*x)) == 1.0*x - 1.0*log(tanh(1.0*x) + 1)
assert integrate(tanh(x)) == x - log(tanh(x) + 1)
def test_issue_8945():
assert integrate(sin(x)**3/x, (x, 0, 1)) == -Si(3)/4 + 3*Si(1)/4
assert integrate(sin(x)**3/x, (x, 0, oo)) == pi/4
assert integrate(cos(x)**2/x**2, x) == -Si(2*x) - cos(2*x)/(2*x) - 1/(2*x)
@slow
def test_issue_7130():
if ON_TRAVIS:
skip("Too slow for travis.")
i, L, a, b = symbols('i L a b')
integrand = (cos(pi*i*x/L)**2 / (a + b*x)).rewrite(exp)
assert x not in integrate(integrand, (x, 0, L)).free_symbols
def test_issue_10567():
a, b, c, t = symbols('a b c t')
vt = Matrix([a*t, b, c])
assert integrate(vt, t) == Integral(vt, t).doit()
assert integrate(vt, t) == Matrix([[a*t**2/2], [b*t], [c*t]])
def test_issue_11856():
t = symbols('t')
assert integrate(sinc(pi*t), t) == Si(pi*t)/pi
def test_issue_4950():
assert integrate((-60*exp(x) - 19.2*exp(4*x))*exp(4*x), x) ==\
-2.4*exp(8*x) - 12.0*exp(5*x)
def test_issue_4968():
assert integrate(sin(log(x**2))) == x*sin(2*log(x))/5 - 2*x*cos(2*log(x))/5
def test_singularities():
assert integrate(1/x**2, (x, -oo, oo)) == oo
assert integrate(1/x**2, (x, -1, 1)) == oo
assert integrate(1/(x - 1)**2, (x, -2, 2)) == oo
assert integrate(1/x**2, (x, 1, -1)) == -oo
assert integrate(1/(x - 1)**2, (x, 2, -2)) == -oo
def test_issue_12645():
x, y = symbols('x y', real=True)
assert (integrate(sin(x*x*x + y*y),
(x, -sqrt(pi - y*y), sqrt(pi - y*y)),
(y, -sqrt(pi), sqrt(pi)))
== Integral(sin(x**3 + y**2),
(x, -sqrt(-y**2 + pi), sqrt(-y**2 + pi)),
(y, -sqrt(pi), sqrt(pi))))
def test_issue_12677():
assert integrate(sin(x) / (cos(x)**3) , (x, 0, pi/6)) == Rational(1,6)
def test_issue_14064():
assert integrate(1/cosh(x), (x, 0, oo)) == pi/2
def test_issue_14027():
assert integrate(1/(1 + exp(x - S(1)/2)/(1 + exp(x))), x) == \
x - exp(S(1)/2)*log(exp(x) + exp(S(1)/2)/(1 + exp(S(1)/2)))/(exp(S(1)/2) + E)
def test_issue_8170():
assert integrate(tan(x), (x, 0, pi/2)) == S.Infinity
def test_issue_8440_14040():
assert integrate(1/x, (x, -1, 1)) == S.NaN
assert integrate(1/(x + 1), (x, -2, 3)) == S.NaN
def test_issue_14096():
assert integrate(1/(x + y)**2, (x, 0, 1)) == -1/(y + 1) + 1/y
assert integrate(1/(1 + x + y + z)**2, (x, 0, 1), (y, 0, 1), (z, 0, 1)) == \
-4*log(4) - 6*log(2) + 9*log(3)
def test_issue_14144():
assert Abs(integrate(1/sqrt(1 - x**3), (x, 0, 1)).n() - 1.402182) < 1e-6
assert Abs(integrate(sqrt(1 - x**3), (x, 0, 1)).n() - 0.841309) < 1e-6
def test_issue_14375():
# This raised a TypeError. The antiderivative has exp_polar, which
# may be possible to unpolarify, so the exact output is not asserted here.
assert integrate(exp(I*x)*log(x), x).has(Ei)
def test_issue_14437():
f = Function('f')(x, y, z)
assert integrate(f, (x, 0, 1), (y, 0, 2), (z, 0, 3)) == \
Integral(f, (x, 0, 1), (y, 0, 2), (z, 0, 3))
def test_issue_14470():
assert integrate(1/sqrt(exp(x) + 1), x) == \
log(-1 + 1/sqrt(exp(x) + 1)) - log(1 + 1/sqrt(exp(x) + 1))
def test_issue_14877():
f = exp(1 - exp(x**2)*x + 2*x**2)*(2*x**3 + x)/(1 - exp(x**2)*x)**2
assert integrate(f, x) == \
-exp(2*x**2 - x*exp(x**2) + 1)/(x*exp(3*x**2) - exp(2*x**2))
def test_issue_14782():
f = sqrt(-x**2 + 1)*(-x**2 + x)
assert integrate(f, [x, -1, 1]) == - pi / 8
assert integrate(f, [x, 0, 1]) == S(1) / 3 - pi / 16
def test_issue_12081():
f = x**(-S(3)/2)*exp(-x)
assert integrate(f, [x, 0, oo]) == oo
def test_issue_15285():
y = 1/x - 1
f = 4*y*exp(-2*y)/x**2
assert integrate(f, [x, 0, 1]) == 1
def test_issue_15432():
assert integrate(x**n * exp(-x) * log(x), (x, 0, oo)).gammasimp() == Piecewise(
(gamma(n + 1)*polygamma(0, n) + gamma(n + 1)/n, re(n) + 1 > 0),
(Integral(x**n*exp(-x)*log(x), (x, 0, oo)), True))
def test_issue_15124():
omega = IndexedBase('omega')
m, p = symbols('m p', cls=Idx)
assert integrate(exp(x*I*(omega[m] + omega[p])), x, conds='none') == \
-I*exp(I*x*omega[m])*exp(I*x*omega[p])/(omega[m] + omega[p])
def test_issue_15218():
assert Eq(x, y).integrate(x) == Eq(x**2/2, x*y)
assert Integral(Eq(x, y), x) == Eq(Integral(x, x), Integral(y, x))
assert Integral(Eq(x, y), x).doit() == Eq(x**2/2, x*y)
def test_issue_15292():
res = integrate(exp(-x**2*cos(2*t)) * cos(x**2*sin(2*t)), (x, 0, oo))
assert isinstance(res, Piecewise)
assert gammasimp((res - sqrt(pi)/2 * cos(t)).subs(t, pi/6)) == 0
def test_issue_4514():
assert integrate(sin(2*x)/sin(x), x) == 2*sin(x)
def test_issue_15457():
x, a, b = symbols('x a b', real=True)
definite = integrate(exp(Abs(x-2)), (x, a, b))
indefinite = integrate(exp(Abs(x-2)), x)
assert definite.subs({a: 1, b: 3}) == -2 + 2*E
assert indefinite.subs(x, 3) - indefinite.subs(x, 1) == -2 + 2*E
assert definite.subs({a: -3, b: -1}) == -exp(3) + exp(5)
assert indefinite.subs(x, -1) - indefinite.subs(x, -3) == -exp(3) + exp(5)
def test_issue_15431():
assert integrate(x*exp(x)*log(x), x) == \
(x*exp(x) - exp(x))*log(x) - exp(x) + Ei(x)
def test_issue_15640_log_substitutions():
f = x/log(x)
F = Ei(2*log(x))
assert integrate(f, x) == F and F.diff(x) == f
f = x**3/log(x)**2
F = -x**4/log(x) + 4*Ei(4*log(x))
assert integrate(f, x) == F and F.diff(x) == f
f = sqrt(log(x))/x**2
F = -sqrt(pi)*erfc(sqrt(log(x)))/2 - sqrt(log(x))/x
assert integrate(f, x) == F and F.diff(x) == f
def test_issue_4311():
x = symbols('x')
assert integrate(x*abs(9-x**2), x) == Integral(x*abs(9-x**2), x)
x = symbols('x', real=True)
assert integrate(x*abs(9-x**2), x) == Piecewise(
(x**4/4 - 9*x**2/2, x <= -3),
(-x**4/4 + 9*x**2/2 - S(81)/2, x <= 3),
(x**4/4 - 9*x**2/2, True))
|
a7565aed280ac4354ed6dca46596b7b5d453ef8c4a45b2ee54b5e6cf54b684bd
|
from sympy import (sin, cos, tan, sec, csc, cot, log, exp, atan, asin, acos,
Symbol, Integral, integrate, pi, Dummy, Derivative,
diff, I, sqrt, erf, Piecewise, Eq, Ne, symbols, Rational,
And, Heaviside, S, asinh, acosh, atanh, acoth, expand,
Function, jacobi, gegenbauer, chebyshevt, chebyshevu,
legendre, hermite, laguerre, assoc_laguerre, uppergamma, li,
Ei, Ci, Si, Chi, Shi, fresnels, fresnelc, polylog, erf, erfi,
sinh, cosh, elliptic_f, elliptic_e)
from sympy.integrals.manualintegrate import (manualintegrate, find_substitutions,
_parts_rule, integral_steps, contains_dont_know, manual_subs)
x, y, z, u, n, a, b, c = symbols('x y z u n a b c')
f = Function('f')
def test_find_substitutions():
assert find_substitutions((cot(x)**2 + 1)**2*csc(x)**2*cot(x)**2, x, u) == \
[(cot(x), 1, -u**6 - 2*u**4 - u**2)]
assert find_substitutions((sec(x)**2 + tan(x) * sec(x)) / (sec(x) + tan(x)),
x, u) == [(sec(x) + tan(x), 1, 1/u)]
assert find_substitutions(x * exp(-x**2), x, u) == [(-x**2, -S.Half, exp(u))]
def test_manualintegrate_polynomials():
assert manualintegrate(y, x) == x*y
assert manualintegrate(exp(2), x) == x * exp(2)
assert manualintegrate(x**2, x) == x**3 / 3
assert manualintegrate(3 * x**2 + 4 * x**3, x) == x**3 + x**4
assert manualintegrate((x + 2)**3, x) == (x + 2)**4 / 4
assert manualintegrate((3*x + 4)**2, x) == (3*x + 4)**3 / 9
assert manualintegrate((u + 2)**3, u) == (u + 2)**4 / 4
assert manualintegrate((3*u + 4)**2, u) == (3*u + 4)**3 / 9
def test_manualintegrate_exponentials():
assert manualintegrate(exp(2*x), x) == exp(2*x) / 2
assert manualintegrate(2**x, x) == (2 ** x) / log(2)
assert manualintegrate(1 / x, x) == log(x)
assert manualintegrate(1 / (2*x + 3), x) == log(2*x + 3) / 2
assert manualintegrate(log(x)**2 / x, x) == log(x)**3 / 3
def test_manualintegrate_parts():
assert manualintegrate(exp(x) * sin(x), x) == \
(exp(x) * sin(x)) / 2 - (exp(x) * cos(x)) / 2
assert manualintegrate(2*x*cos(x), x) == 2*x*sin(x) + 2*cos(x)
assert manualintegrate(x * log(x), x) == x**2*log(x)/2 - x**2/4
assert manualintegrate(log(x), x) == x * log(x) - x
assert manualintegrate((3*x**2 + 5) * exp(x), x) == \
3*x**2*exp(x) - 6*x*exp(x) + 11*exp(x)
assert manualintegrate(atan(x), x) == x*atan(x) - log(x**2 + 1)/2
# Make sure _parts_rule does not go into an infinite loop here
assert manualintegrate(log(1/x)/(x + 1), x).has(Integral)
# Make sure _parts_rule doesn't pick u = constant but can pick dv =
# constant if necessary, e.g. for integrate(atan(x))
assert _parts_rule(cos(x), x) == None
assert _parts_rule(exp(x), x) == None
assert _parts_rule(x**2, x) == None
result = _parts_rule(atan(x), x)
assert result[0] == atan(x) and result[1] == 1
def test_manualintegrate_trigonometry():
assert manualintegrate(sin(x), x) == -cos(x)
assert manualintegrate(tan(x), x) == -log(cos(x))
assert manualintegrate(sec(x), x) == log(sec(x) + tan(x))
assert manualintegrate(csc(x), x) == -log(csc(x) + cot(x))
assert manualintegrate(sin(x) * cos(x), x) in [sin(x) ** 2 / 2, -cos(x)**2 / 2]
assert manualintegrate(-sec(x) * tan(x), x) == -sec(x)
assert manualintegrate(csc(x) * cot(x), x) == -csc(x)
assert manualintegrate(sec(x)**2, x) == tan(x)
assert manualintegrate(csc(x)**2, x) == -cot(x)
assert manualintegrate(x * sec(x**2), x) == log(tan(x**2) + sec(x**2))/2
assert manualintegrate(cos(x)*csc(sin(x)), x) == -log(cot(sin(x)) + csc(sin(x)))
assert manualintegrate(cos(3*x)*sec(x), x) == -x + sin(2*x)
assert manualintegrate(sin(3*x)*sec(x), x) == \
-3*log(cos(x)) + 2*log(cos(x)**2) - 2*cos(x)**2
def test_manualintegrate_trigpowers():
assert manualintegrate(sin(x)**2 * cos(x), x) == sin(x)**3 / 3
assert manualintegrate(sin(x)**2 * cos(x) **2, x) == \
x / 8 - sin(4*x) / 32
assert manualintegrate(sin(x) * cos(x)**3, x) == -cos(x)**4 / 4
assert manualintegrate(sin(x)**3 * cos(x)**2, x) == \
cos(x)**5 / 5 - cos(x)**3 / 3
assert manualintegrate(tan(x)**3 * sec(x), x) == sec(x)**3/3 - sec(x)
assert manualintegrate(tan(x) * sec(x) **2, x) == sec(x)**2/2
assert manualintegrate(cot(x)**5 * csc(x), x) == \
-csc(x)**5/5 + 2*csc(x)**3/3 - csc(x)
assert manualintegrate(cot(x)**2 * csc(x)**6, x) == \
-cot(x)**7/7 - 2*cot(x)**5/5 - cot(x)**3/3
def test_manualintegrate_inversetrig():
# atan
assert manualintegrate(exp(x) / (1 + exp(2*x)), x) == atan(exp(x))
assert manualintegrate(1 / (4 + 9 * x**2), x) == atan(3 * x/2) / 6
assert manualintegrate(1 / (16 + 16 * x**2), x) == atan(x) / 16
assert manualintegrate(1 / (4 + x**2), x) == atan(x / 2) / 2
assert manualintegrate(1 / (1 + 4 * x**2), x) == atan(2*x) / 2
assert manualintegrate(1/(a + b*x**2), x) == \
Piecewise((atan(x/sqrt(a/b))/(b*sqrt(a/b)), a/b > 0), \
(-acoth(x/sqrt(-a/b))/(b*sqrt(-a/b)), And(a/b < 0, x**2 > -a/b)), \
(-atanh(x/sqrt(-a/b))/(b*sqrt(-a/b)), And(a/b < 0, x**2 < -a/b)))
assert manualintegrate(1/(4 + b*x**2), x) == \
Piecewise((atan(x/(2*sqrt(1/b)))/(2*b*sqrt(1/b)), 4/b > 0), \
(-acoth(x/(2*sqrt(-1/b)))/(2*b*sqrt(-1/b)), And(4/b < 0, x**2 > -4/b)), \
(-atanh(x/(2*sqrt(-1/b)))/(2*b*sqrt(-1/b)), And(4/b < 0, x**2 < -4/b)))
assert manualintegrate(1/(a + 4*x**2), x) == \
Piecewise((atan(2*x/sqrt(a))/(2*sqrt(a)), a/4 > 0), \
(-acoth(2*x/sqrt(-a))/(2*sqrt(-a)), And(a/4 < 0, x**2 > -a/4)), \
(-atanh(2*x/sqrt(-a))/(2*sqrt(-a)), And(a/4 < 0, x**2 < -a/4)))
assert manualintegrate(1/(4 + 4*x**2), x) == atan(x) / 4
# asin
assert manualintegrate(1/sqrt(1-x**2), x) == asin(x)
assert manualintegrate(1/sqrt(4-4*x**2), x) == asin(x)/2
assert manualintegrate(3/sqrt(1-9*x**2), x) == asin(3*x)
assert manualintegrate(1/sqrt(4-9*x**2), x) == asin(3*x/2)/3
# asinh
assert manualintegrate(1/sqrt(x**2 + 1), x) == \
asinh(x)
assert manualintegrate(1/sqrt(x**2 + 4), x) == \
asinh(x/2)
assert manualintegrate(1/sqrt(4*x**2 + 4), x) == \
asinh(x)/2
assert manualintegrate(1/sqrt(4*x**2 + 1), x) == \
asinh(2*x)/2
assert manualintegrate(1/sqrt(a*x**2 + 1), x) == \
Piecewise((sqrt(-1/a)*asin(x*sqrt(-a)), a < 0), (sqrt(1/a)*asinh(sqrt(a)*x), a > 0))
assert manualintegrate(1/sqrt(a + x**2), x) == \
Piecewise((asinh(x*sqrt(1/a)), a > 0), (acosh(x*sqrt(-1/a)), a < 0))
# acosh
assert manualintegrate(1/sqrt(x**2 - 1), x) == \
acosh(x)
assert manualintegrate(1/sqrt(x**2 - 4), x) == \
acosh(x/2)
assert manualintegrate(1/sqrt(4*x**2 - 4), x) == \
acosh(x)/2
assert manualintegrate(1/sqrt(9*x**2 - 1), x) == \
acosh(3*x)/3
assert manualintegrate(1/sqrt(a*x**2 - 4), x) == \
Piecewise((sqrt(1/a)*acosh(sqrt(a)*x/2), a > 0))
assert manualintegrate(1/sqrt(-a + 4*x**2), x) == \
Piecewise((asinh(2*x*sqrt(-1/a))/2, -a > 0), (acosh(2*x*sqrt(1/a))/2, -a < 0))
# piecewise
assert manualintegrate(1/sqrt(a-b*x**2), x) == \
Piecewise((sqrt(a/b)*asin(x*sqrt(b/a))/sqrt(a), And(-b < 0, a > 0)),
(sqrt(-a/b)*asinh(x*sqrt(-b/a))/sqrt(a), And(-b > 0, a > 0)),
(sqrt(a/b)*acosh(x*sqrt(b/a))/sqrt(-a), And(-b > 0, a < 0)))
assert manualintegrate(1/sqrt(a + b*x**2), x) == \
Piecewise((sqrt(-a/b)*asin(x*sqrt(-b/a))/sqrt(a), And(a > 0, b < 0)),
(sqrt(a/b)*asinh(x*sqrt(b/a))/sqrt(a), And(a > 0, b > 0)),
(sqrt(-a/b)*acosh(x*sqrt(-b/a))/sqrt(-a), And(a < 0, b > 0)))
def test_manualintegrate_trig_substitution():
assert manualintegrate(sqrt(16*x**2 - 9)/x, x) == \
Piecewise((sqrt(16*x**2 - 9) - 3*acos(3/(4*x)),
And(x < 3*S.One/4, x > -3*S.One/4)))
assert manualintegrate(1/(x**4 * sqrt(25-x**2)), x) == \
Piecewise((-sqrt(-x**2/25 + 1)/(125*x) -
(-x**2/25 + 1)**(3*S.Half)/(15*x**3), And(x < 5, x > -5)))
assert manualintegrate(x**7/(49*x**2 + 1)**(3 * S.Half), x) == \
((49*x**2 + 1)**(5*S.Half)/28824005 -
(49*x**2 + 1)**(3*S.Half)/5764801 +
3*sqrt(49*x**2 + 1)/5764801 + 1/(5764801*sqrt(49*x**2 + 1)))
def test_manualintegrate_trivial_substitution():
assert manualintegrate((exp(x) - exp(-x))/x, x) == -Ei(-x) + Ei(x)
f = Function('f')
assert manualintegrate((f(x) - f(-x))/x, x) == \
-Integral(f(-x)/x, x) + Integral(f(x)/x, x)
def test_manualintegrate_rational():
assert manualintegrate(1/(4 - x**2), x) == Piecewise((acoth(x/2)/2, x**2 > 4), (atanh(x/2)/2, x**2 < 4))
assert manualintegrate(1/(-1 + x**2), x) == Piecewise((-acoth(x), x**2 > 1), (-atanh(x), x**2 < 1))
def test_manualintegrate_special():
f, F = 4*exp(-x**2/3), 2*sqrt(3)*sqrt(pi)*erf(sqrt(3)*x/3)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = 3*exp(4*x**2), 3*sqrt(pi)*erfi(2*x)/4
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = x**(S(1)/3)*exp(-x/8), -16*uppergamma(S(4)/3, x/8)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = exp(2*x)/x, Ei(2*x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = exp(1 + 2*x - x**2), sqrt(pi)*exp(2)*erf(x - 1)/2
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f = sin(x**2 + 4*x + 1)
F = (sqrt(2)*sqrt(pi)*(-sin(3)*fresnelc(sqrt(2)*(2*x + 4)/(2*sqrt(pi))) +
cos(3)*fresnels(sqrt(2)*(2*x + 4)/(2*sqrt(pi))))/2)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = cos(4*x**2), sqrt(2)*sqrt(pi)*fresnelc(2*sqrt(2)*x/sqrt(pi))/4
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = sin(3*x + 2)/x, sin(2)*Ci(3*x) + cos(2)*Si(3*x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = sinh(3*x - 2)/x, -sinh(2)*Chi(3*x) + cosh(2)*Shi(3*x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = 5*cos(2*x - 3)/x, 5*cos(3)*Ci(2*x) + 5*sin(3)*Si(2*x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = cosh(x/2)/x, Chi(x/2)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = cos(x**2)/x, Ci(x**2)/2
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = 1/log(2*x + 1), li(2*x + 1)/2
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = polylog(2, 5*x)/x, polylog(3, 5*x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = 5/sqrt(3 - 2*sin(x)**2), 5*sqrt(3)*elliptic_f(x, S(2)/3)/3
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
f, F = sqrt(4 + 9*sin(x)**2), 2*elliptic_e(x, -S(9)/4)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
def test_manualintegrate_derivative():
assert manualintegrate(pi * Derivative(x**2 + 2*x + 3), x) == \
pi * ((x**2 + 2*x + 3))
assert manualintegrate(Derivative(x**2 + 2*x + 3, y), x) == \
Integral(Derivative(x**2 + 2*x + 3, y))
assert manualintegrate(Derivative(sin(x), x, x, x, y), x) == \
Derivative(sin(x), x, x, y)
def test_manualintegrate_Heaviside():
assert manualintegrate(Heaviside(x), x) == x*Heaviside(x)
assert manualintegrate(x*Heaviside(2), x) == x**2/2
assert manualintegrate(x*Heaviside(-2), x) == 0
assert manualintegrate(x*Heaviside( x), x) == x**2*Heaviside( x)/2
assert manualintegrate(x*Heaviside(-x), x) == x**2*Heaviside(-x)/2
assert manualintegrate(Heaviside(2*x + 4), x) == (x+2)*Heaviside(2*x + 4)
assert manualintegrate(x*Heaviside(x), x) == x**2*Heaviside(x)/2
assert manualintegrate(Heaviside(x + 1)*Heaviside(1 - x)*x**2, x) == \
((x**3/3 + S(1)/3)*Heaviside(x + 1) - S(2)/3)*Heaviside(-x + 1)
y = Symbol('y')
assert manualintegrate(sin(7 + x)*Heaviside(3*x - 7), x) == \
(- cos(x + 7) + cos(S(28)/3))*Heaviside(3*x - S(7))
assert manualintegrate(sin(y + x)*Heaviside(3*x - y), x) == \
(cos(4*y/3) - cos(x + y))*Heaviside(3*x - y)
def test_manualintegrate_orthogonal_poly():
n = symbols('n')
a, b = 7, S(5)/3
polys = [jacobi(n, a, b, x), gegenbauer(n, a, x), chebyshevt(n, x),
chebyshevu(n, x), legendre(n, x), hermite(n, x), laguerre(n, x),
assoc_laguerre(n, a, x)]
for p in polys:
integral = manualintegrate(p, x)
for deg in [-2, -1, 0, 1, 3, 5, 8]:
# some accept negative "degree", some do not
try:
p_subbed = p.subs(n, deg)
except ValueError:
continue
assert (integral.subs(n, deg).diff(x) - p_subbed).expand() == 0
# can also integrate simple expressions with these polynomials
q = x*p.subs(x, 2*x + 1)
integral = manualintegrate(q, x)
for deg in [2, 4, 7]:
assert (integral.subs(n, deg).diff(x) - q.subs(n, deg)).expand() == 0
# cannot integrate with respect to any other parameter
t = symbols('t')
for i in range(len(p.args) - 1):
new_args = list(p.args)
new_args[i] = t
assert isinstance(manualintegrate(p.func(*new_args), t), Integral)
def test_issue_6799():
r, x, phi = map(Symbol, 'r x phi'.split())
n = Symbol('n', integer=True, positive=True)
integrand = (cos(n*(x-phi))*cos(n*x))
limits = (x, -pi, pi)
assert manualintegrate(integrand, x) == \
((n*x/2 + sin(2*n*x)/4)*cos(n*phi) - sin(n*phi)*cos(n*x)**2/2)/n
assert r * integrate(integrand, limits).trigsimp() / pi == r * cos(n * phi)
assert not integrate(integrand, limits).has(Dummy)
def test_issue_12251():
assert manualintegrate(x**y, x) == Piecewise(
(x**(y + 1)/(y + 1), Ne(y, -1)), (log(x), True))
def test_issue_3796():
assert manualintegrate(diff(exp(x + x**2)), x) == exp(x + x**2)
assert integrate(x * exp(x**4), x, risch=False) == -I*sqrt(pi)*erf(I*x**2)/4
def test_manual_true():
assert integrate(exp(x) * sin(x), x, manual=True) == \
(exp(x) * sin(x)) / 2 - (exp(x) * cos(x)) / 2
assert integrate(sin(x) * cos(x), x, manual=True) in \
[sin(x) ** 2 / 2, -cos(x)**2 / 2]
def test_issue_6746():
y = Symbol('y')
n = Symbol('n')
assert manualintegrate(y**x, x) == Piecewise(
(y**x/log(y), Ne(log(y), 0)), (x, True))
assert manualintegrate(y**(n*x), x) == Piecewise(
(Piecewise(
(y**(n*x)/log(y), Ne(log(y), 0)),
(n*x, True)
)/n, Ne(n, 0)),
(x, True))
assert manualintegrate(exp(n*x), x) == Piecewise(
(exp(n*x)/n, Ne(n, 0)), (x, True))
y = Symbol('y', positive=True)
assert manualintegrate((y + 1)**x, x) == (y + 1)**x/log(y + 1)
y = Symbol('y', zero=True)
assert manualintegrate((y + 1)**x, x) == x
y = Symbol('y')
n = Symbol('n', nonzero=True)
assert manualintegrate(y**(n*x), x) == Piecewise(
(y**(n*x)/log(y), Ne(log(y), 0)), (n*x, True))/n
y = Symbol('y', positive=True)
assert manualintegrate((y + 1)**(n*x), x) == \
(y + 1)**(n*x)/(n*log(y + 1))
a = Symbol('a', negative=True)
b = Symbol('b')
assert manualintegrate(1/(a + b*x**2), x) == \
Piecewise((atan(x/sqrt(a/b))/(b*sqrt(a/b)), a/b > 0), \
(-acoth(x/sqrt(-a/b))/(b*sqrt(-a/b)), And(a/b < 0, x**2 > -a/b)), \
(-atanh(x/sqrt(-a/b))/(b*sqrt(-a/b)), And(a/b < 0, x**2 < -a/b)))
b = Symbol('b', negative=True)
assert manualintegrate(1/(a + b*x**2), x) == \
atan(x/(sqrt(-a)*sqrt(-1/b)))/(b*sqrt(-a)*sqrt(-1/b))
assert manualintegrate(1/((x**a + y**b + 4)*sqrt(a*x**2 + 1)), x) == \
y**(-b)*Integral(x**(-a)/(y**(-b)*sqrt(a*x**2 + 1) +
x**(-a)*sqrt(a*x**2 + 1) + 4*x**(-a)*y**(-b)*sqrt(a*x**2 + 1)), x)
assert manualintegrate(1/((x**2 + 4)*sqrt(4*x**2 + 1)), x) == \
Integral(1/((x**2 + 4)*sqrt(4*x**2 + 1)), x)
assert manualintegrate(1/(x - a**x + x*b**2), x) == \
Integral(1/(-a**x + b**2*x + x), x)
def test_issue_2850():
assert manualintegrate(asin(x)*log(x), x) == -x*asin(x) - sqrt(-x**2 + 1) \
+ (x*asin(x) + sqrt(-x**2 + 1))*log(x) - Integral(sqrt(-x**2 + 1)/x, x)
assert manualintegrate(acos(x)*log(x), x) == -x*acos(x) + sqrt(-x**2 + 1) + \
(x*acos(x) - sqrt(-x**2 + 1))*log(x) + Integral(sqrt(-x**2 + 1)/x, x)
assert manualintegrate(atan(x)*log(x), x) == -x*atan(x) + (x*atan(x) - \
log(x**2 + 1)/2)*log(x) + log(x**2 + 1)/2 + Integral(log(x**2 + 1)/x, x)/2
def test_issue_9462():
assert manualintegrate(sin(2*x)*exp(x), x) == exp(x)*sin(2*x)/5 - 2*exp(x)*cos(2*x)/5
assert not contains_dont_know(integral_steps(sin(2*x)*exp(x), x))
assert manualintegrate((x - 3) / (x**2 - 2*x + 2)**2, x) == \
Integral(x/(x**4 - 4*x**3 + 8*x**2 - 8*x + 4), x) \
- 3*Integral(1/(x**4 - 4*x**3 + 8*x**2 - 8*x + 4), x)
def test_cyclic_parts():
f = cos(x)*exp(x/4)
F = 16*exp(x/4)*sin(x)/17 + 4*exp(x/4)*cos(x)/17
assert manualintegrate(f, x) == F and F.diff(x) == f
f = x*cos(x)*exp(x/4)
F = (x*(16*exp(x/4)*sin(x)/17 + 4*exp(x/4)*cos(x)/17) -
128*exp(x/4)*sin(x)/289 + 240*exp(x/4)*cos(x)/289)
assert manualintegrate(f, x) == F and F.diff(x) == f
def test_issue_10847():
assert manualintegrate(x**2 / (x**2 - c), x) == c*Piecewise((atan(x/sqrt(-c))/sqrt(-c), -c > 0), \
(-acoth(x/sqrt(c))/sqrt(c), And(-c < 0, x**2 > c)), \
(-atanh(x/sqrt(c))/sqrt(c), And(-c < 0, x**2 < c))) + x
assert manualintegrate(sqrt(x - y) * log(z / x), x) == 4*y**2*Piecewise((atan(sqrt(x - y)/sqrt(y))/sqrt(y), y > 0), \
(-acoth(sqrt(x - y)/sqrt(-y))/sqrt(-y), \
And(x - y > -y, y < 0)), \
(-atanh(sqrt(x - y)/sqrt(-y))/sqrt(-y), \
And(x - y < -y, y < 0)))/3 \
- 4*y*sqrt(x - y)/3 + 2*(x - y)**(S(3)/2)*log(z/x)/3 \
+ 4*(x - y)**(S(3)/2)/9
assert manualintegrate(sqrt(x) * log(x), x) == 2*x**(S(3)/2)*log(x)/3 - 4*x**(S(3)/2)/9
assert manualintegrate(sqrt(a*x + b) / x, x) == -2*b*Piecewise((-atan(sqrt(a*x + b)/sqrt(-b))/sqrt(-b), -b > 0), \
(acoth(sqrt(a*x + b)/sqrt(b))/sqrt(b), And(-b < 0, a*x + b > b)), \
(atanh(sqrt(a*x + b)/sqrt(b))/sqrt(b), And(-b < 0, a*x + b < b))) \
+ 2*sqrt(a*x + b)
assert expand(manualintegrate(sqrt(a*x + b) / (x + c), x)) == -2*a*c*Piecewise((atan(sqrt(a*x + b)/sqrt(a*c - b))/sqrt(a*c - b), \
a*c - b > 0), (-acoth(sqrt(a*x + b)/sqrt(-a*c + b))/sqrt(-a*c + b), And(a*c - b < 0, a*x + b > -a*c + b)), \
(-atanh(sqrt(a*x + b)/sqrt(-a*c + b))/sqrt(-a*c + b), And(a*c - b < 0, a*x + b < -a*c + b))) \
+ 2*b*Piecewise((atan(sqrt(a*x + b)/sqrt(a*c - b))/sqrt(a*c - b), a*c - b > 0), \
(-acoth(sqrt(a*x + b)/sqrt(-a*c + b))/sqrt(-a*c + b), And(a*c - b < 0, a*x + b > -a*c + b)), \
(-atanh(sqrt(a*x + b)/sqrt(-a*c + b))/sqrt(-a*c + b), And(a*c - b < 0, a*x + b < -a*c + b))) + 2*sqrt(a*x + b)
assert manualintegrate((4*x**4 + 4*x**3 + 16*x**2 + 12*x + 8) \
/ (x**6 + 2*x**5 + 3*x**4 + 4*x**3 + 3*x**2 + 2*x + 1), x) == \
2*x/(x**2 + 1) + 3*atan(x) - 1/(x**2 + 1) - 3/(x + 1)
assert manualintegrate(sqrt(2*x + 3) / (x + 1), x) == 2*sqrt(2*x + 3) - log(sqrt(2*x + 3) + 1) + log(sqrt(2*x + 3) - 1)
assert manualintegrate(sqrt(2*x + 3) / 2 * x, x) == (2*x + 3)**(S(5)/2)/20 - (2*x + 3)**(S(3)/2)/4
assert manualintegrate(x**Rational(3,2) * log(x), x) == 2*x**Rational(5,2)*log(x)/5 - 4*x**Rational(5,2)/25
assert manualintegrate(x**(-3) * log(x), x) == -log(x)/(2*x**2) - 1/(4*x**2)
assert manualintegrate(log(y)/(y**2*(1 - 1/y)), y) == \
log(y)*log(-1 + 1/y) - Integral(log(-1 + 1/y)/y, y)
def test_issue_12899():
assert manualintegrate(f(x,y).diff(x),y) == Integral(Derivative(f(x,y),x),y)
assert manualintegrate(f(x,y).diff(y).diff(x),y) == Derivative(f(x,y),x)
def test_constant_independent_of_symbol():
assert manualintegrate(Integral(y, (x, 1, 2)), x) == \
x*Integral(y, (x, 1, 2))
def test_issue_12641():
assert manualintegrate(sin(2*x), x) == -cos(2*x)/2
assert manualintegrate(cos(x)*sin(2*x), x) == -2*cos(x)**3/3
assert manualintegrate((sin(2*x)*cos(x))/(1 + cos(x)), x) == \
-2*log(cos(x) + 1) - cos(x)**2 + 2*cos(x)
def test_issue_13297():
assert manualintegrate(sin(x) * cos(x)**5, x) == -cos(x)**6 / 6
def test_issue_14470():
assert manualintegrate(1/(x*sqrt(x + 1)), x) == \
log(-1 + 1/sqrt(x + 1)) - log(1 + 1/sqrt(x + 1))
def test_issue_9858():
assert manualintegrate(exp(x)*cos(exp(x)), x) == sin(exp(x))
assert manualintegrate(exp(2*x)*cos(exp(x)), x) == \
exp(x)*sin(exp(x)) + cos(exp(x))
res = manualintegrate(exp(10*x)*sin(exp(x)), x)
assert not res.has(Integral)
assert res.diff(x) == exp(10*x)*sin(exp(x))
# an example with many similar integrations by parts
assert manualintegrate(sum([x*exp(k*x) for k in range(1, 8)]), x) == (
x*exp(7*x)/7 + x*exp(6*x)/6 + x*exp(5*x)/5 + x*exp(4*x)/4 +
x*exp(3*x)/3 + x*exp(2*x)/2 + x*exp(x) - exp(7*x)/49 -exp(6*x)/36 -
exp(5*x)/25 - exp(4*x)/16 - exp(3*x)/9 - exp(2*x)/4 - exp(x))
def test_issue_8520():
assert manualintegrate(x/(x**4 + 1), x) == atan(x**2)/2
assert manualintegrate(x**2/(x**6 + 25), x) == atan(x**3/5)/15
f = x/(9*x**4 + 4)**2
assert manualintegrate(f, x).diff(x).factor() == f
def test_manual_subs():
x, y = symbols('x y')
expr = log(x) + exp(x)
# if log(x) is y, then exp(y) is x
assert manual_subs(expr, log(x), y) == y + exp(exp(y))
# if exp(x) is y, then log(y) need not be x
assert manual_subs(expr, exp(x), y) == log(x) + y
def test_issue_15471():
f = log(x)*cos(log(x))/x**(S(3)/4)
F = -128*x**(1/4)*sin(log(x))/289 + 240*x**(1/4)*cos(log(x))/289 + (16*x**(1/4)*sin(log(x))/17 + 4*x**(1/4)*cos(log(x))/17)*log(x)
assert manualintegrate(f, x) == F and F.diff(x).equals(f)
|
891320f51b6f9dc9fdc8fe7474ba4f7d26b7deed86dc0fd78872aaf145e43ce2
|
"""Test whether all elements of cls.args are instances of Basic. """
# NOTE: keep tests sorted by (module, class name) key. If a class can't
# be instantiated, add it here anyway with @SKIP("abstract class) (see
# e.g. Function).
import os
import re
import io
from sympy import (Basic, S, symbols, sqrt, sin, oo, Interval, exp, Lambda, pi,
Eq, log, Function)
from sympy.core.compatibility import range
from sympy.utilities.pytest import XFAIL, SKIP
x, y, z = symbols('x,y,z')
def test_all_classes_are_tested():
this = os.path.split(__file__)[0]
path = os.path.join(this, os.pardir, os.pardir)
sympy_path = os.path.abspath(path)
prefix = os.path.split(sympy_path)[0] + os.sep
re_cls = re.compile(r"^class ([A-Za-z][A-Za-z0-9_]*)\s*\(", re.MULTILINE)
modules = {}
for root, dirs, files in os.walk(sympy_path):
module = root.replace(prefix, "").replace(os.sep, ".")
for file in files:
if file.startswith(("_", "test_", "bench_")):
continue
if not file.endswith(".py"):
continue
with io.open(os.path.join(root, file), "r", encoding='utf-8') as f:
text = f.read()
submodule = module + '.' + file[:-3]
names = re_cls.findall(text)
if not names:
continue
try:
mod = __import__(submodule, fromlist=names)
except ImportError:
continue
def is_Basic(name):
cls = getattr(mod, name)
if hasattr(cls, '_sympy_deprecated_func'):
cls = cls._sympy_deprecated_func
return issubclass(cls, Basic)
names = list(filter(is_Basic, names))
if names:
modules[submodule] = names
ns = globals()
failed = []
for module, names in modules.items():
mod = module.replace('.', '__')
for name in names:
test = 'test_' + mod + '__' + name
if test not in ns:
failed.append(module + '.' + name)
assert not failed, "Missing classes: %s. Please add tests for these to sympy/core/tests/test_args.py." % ", ".join(failed)
def _test_args(obj):
return all(isinstance(arg, Basic) for arg in obj.args)
def test_sympy__assumptions__assume__AppliedPredicate():
from sympy.assumptions.assume import AppliedPredicate, Predicate
from sympy import Q
assert _test_args(AppliedPredicate(Predicate("test"), 2))
assert _test_args(Q.is_true(True))
def test_sympy__assumptions__assume__Predicate():
from sympy.assumptions.assume import Predicate
assert _test_args(Predicate("test"))
def test_sympy__assumptions__sathandlers__UnevaluatedOnFree():
from sympy.assumptions.sathandlers import UnevaluatedOnFree
from sympy import Q
assert _test_args(UnevaluatedOnFree(Q.positive))
assert _test_args(UnevaluatedOnFree(Q.positive(x)))
assert _test_args(UnevaluatedOnFree(Q.positive(x*y)))
def test_sympy__assumptions__sathandlers__AllArgs():
from sympy.assumptions.sathandlers import AllArgs
from sympy import Q
assert _test_args(AllArgs(Q.positive))
assert _test_args(AllArgs(Q.positive(x)))
assert _test_args(AllArgs(Q.positive(x*y)))
def test_sympy__assumptions__sathandlers__AnyArgs():
from sympy.assumptions.sathandlers import AnyArgs
from sympy import Q
assert _test_args(AnyArgs(Q.positive))
assert _test_args(AnyArgs(Q.positive(x)))
assert _test_args(AnyArgs(Q.positive(x*y)))
def test_sympy__assumptions__sathandlers__ExactlyOneArg():
from sympy.assumptions.sathandlers import ExactlyOneArg
from sympy import Q
assert _test_args(ExactlyOneArg(Q.positive))
assert _test_args(ExactlyOneArg(Q.positive(x)))
assert _test_args(ExactlyOneArg(Q.positive(x*y)))
def test_sympy__assumptions__sathandlers__CheckOldAssump():
from sympy.assumptions.sathandlers import CheckOldAssump
from sympy import Q
assert _test_args(CheckOldAssump(Q.positive))
assert _test_args(CheckOldAssump(Q.positive(x)))
assert _test_args(CheckOldAssump(Q.positive(x*y)))
def test_sympy__assumptions__sathandlers__CheckIsPrime():
from sympy.assumptions.sathandlers import CheckIsPrime
from sympy import Q
# Input must be a number
assert _test_args(CheckIsPrime(Q.positive))
assert _test_args(CheckIsPrime(Q.positive(5)))
@SKIP("abstract Class")
def test_sympy__codegen__ast__AssignmentBase():
from sympy.codegen.ast import AssignmentBase
assert _test_args(AssignmentBase(x, 1))
@SKIP("abstract Class")
def test_sympy__codegen__ast__AugmentedAssignment():
from sympy.codegen.ast import AugmentedAssignment
assert _test_args(AugmentedAssignment(x, 1))
def test_sympy__codegen__ast__AddAugmentedAssignment():
from sympy.codegen.ast import AddAugmentedAssignment
assert _test_args(AddAugmentedAssignment(x, 1))
def test_sympy__codegen__ast__SubAugmentedAssignment():
from sympy.codegen.ast import SubAugmentedAssignment
assert _test_args(SubAugmentedAssignment(x, 1))
def test_sympy__codegen__ast__MulAugmentedAssignment():
from sympy.codegen.ast import MulAugmentedAssignment
assert _test_args(MulAugmentedAssignment(x, 1))
def test_sympy__codegen__ast__DivAugmentedAssignment():
from sympy.codegen.ast import DivAugmentedAssignment
assert _test_args(DivAugmentedAssignment(x, 1))
def test_sympy__codegen__ast__ModAugmentedAssignment():
from sympy.codegen.ast import ModAugmentedAssignment
assert _test_args(ModAugmentedAssignment(x, 1))
def test_sympy__codegen__ast__CodeBlock():
from sympy.codegen.ast import CodeBlock, Assignment
assert _test_args(CodeBlock(Assignment(x, 1), Assignment(y, 2)))
def test_sympy__codegen__ast__For():
from sympy.codegen.ast import For, CodeBlock, AddAugmentedAssignment
from sympy import Range
assert _test_args(For(x, Range(10), CodeBlock(AddAugmentedAssignment(y, 1))))
def test_sympy__codegen__ast__Token():
from sympy.codegen.ast import Token
assert _test_args(Token())
def test_sympy__codegen__ast__ContinueToken():
from sympy.codegen.ast import ContinueToken
assert _test_args(ContinueToken())
def test_sympy__codegen__ast__BreakToken():
from sympy.codegen.ast import BreakToken
assert _test_args(BreakToken())
def test_sympy__codegen__ast__NoneToken():
from sympy.codegen.ast import NoneToken
assert _test_args(NoneToken())
def test_sympy__codegen__ast__String():
from sympy.codegen.ast import String
assert _test_args(String('foobar'))
def test_sympy__codegen__ast__QuotedString():
from sympy.codegen.ast import QuotedString
assert _test_args(QuotedString('foobar'))
def test_sympy__codegen__ast__Comment():
from sympy.codegen.ast import Comment
assert _test_args(Comment('this is a comment'))
def test_sympy__codegen__ast__Node():
from sympy.codegen.ast import Node
assert _test_args(Node())
assert _test_args(Node(attrs={1, 2, 3}))
def test_sympy__codegen__ast__Type():
from sympy.codegen.ast import Type
assert _test_args(Type('float128'))
def test_sympy__codegen__ast__IntBaseType():
from sympy.codegen.ast import IntBaseType
assert _test_args(IntBaseType('bigint'))
def test_sympy__codegen__ast___SizedIntType():
from sympy.codegen.ast import _SizedIntType
assert _test_args(_SizedIntType('int128', 128))
def test_sympy__codegen__ast__SignedIntType():
from sympy.codegen.ast import SignedIntType
assert _test_args(SignedIntType('int128_with_sign', 128))
def test_sympy__codegen__ast__UnsignedIntType():
from sympy.codegen.ast import UnsignedIntType
assert _test_args(UnsignedIntType('unt128', 128))
def test_sympy__codegen__ast__FloatBaseType():
from sympy.codegen.ast import FloatBaseType
assert _test_args(FloatBaseType('positive_real'))
def test_sympy__codegen__ast__FloatType():
from sympy.codegen.ast import FloatType
assert _test_args(FloatType('float242', 242, nmant=142, nexp=99))
def test_sympy__codegen__ast__ComplexBaseType():
from sympy.codegen.ast import ComplexBaseType
assert _test_args(ComplexBaseType('positive_cmplx'))
def test_sympy__codegen__ast__ComplexType():
from sympy.codegen.ast import ComplexType
assert _test_args(ComplexType('complex42', 42, nmant=15, nexp=5))
def test_sympy__codegen__ast__Attribute():
from sympy.codegen.ast import Attribute
assert _test_args(Attribute('noexcept'))
def test_sympy__codegen__ast__Variable():
from sympy.codegen.ast import Variable, Type, value_const
assert _test_args(Variable(x))
assert _test_args(Variable(y, Type('float32'), {value_const}))
assert _test_args(Variable(z, type=Type('float64')))
def test_sympy__codegen__ast__Pointer():
from sympy.codegen.ast import Pointer, Type, pointer_const
assert _test_args(Pointer(x))
assert _test_args(Pointer(y, type=Type('float32')))
assert _test_args(Pointer(z, Type('float64'), {pointer_const}))
def test_sympy__codegen__ast__Declaration():
from sympy.codegen.ast import Declaration, Variable, Type
vx = Variable(x, type=Type('float'))
assert _test_args(Declaration(vx))
def test_sympy__codegen__ast__While():
from sympy.codegen.ast import While, AddAugmentedAssignment
assert _test_args(While(abs(x) < 1, [AddAugmentedAssignment(x, -1)]))
def test_sympy__codegen__ast__Scope():
from sympy.codegen.ast import Scope, AddAugmentedAssignment
assert _test_args(Scope([AddAugmentedAssignment(x, -1)]))
def test_sympy__codegen__ast__Stream():
from sympy.codegen.ast import Stream
assert _test_args(Stream('stdin'))
def test_sympy__codegen__ast__Print():
from sympy.codegen.ast import Print
assert _test_args(Print([x, y]))
assert _test_args(Print([x, y], "%d %d"))
def test_sympy__codegen__ast__FunctionPrototype():
from sympy.codegen.ast import FunctionPrototype, real, Declaration, Variable
inp_x = Declaration(Variable(x, type=real))
assert _test_args(FunctionPrototype(real, 'pwer', [inp_x]))
def test_sympy__codegen__ast__FunctionDefinition():
from sympy.codegen.ast import FunctionDefinition, real, Declaration, Variable, Assignment
inp_x = Declaration(Variable(x, type=real))
assert _test_args(FunctionDefinition(real, 'pwer', [inp_x], [Assignment(x, x**2)]))
def test_sympy__codegen__ast__Return():
from sympy.codegen.ast import Return
assert _test_args(Return(x))
def test_sympy__codegen__ast__FunctionCall():
from sympy.codegen.ast import FunctionCall
assert _test_args(FunctionCall('pwer', [x]))
def test_sympy__codegen__ast__Element():
from sympy.codegen.ast import Element
assert _test_args(Element('x', range(3)))
def test_sympy__codegen__cnodes__CommaOperator():
from sympy.codegen.cnodes import CommaOperator
assert _test_args(CommaOperator(1, 2))
def test_sympy__codegen__cnodes__goto():
from sympy.codegen.cnodes import goto
assert _test_args(goto('early_exit'))
def test_sympy__codegen__cnodes__Label():
from sympy.codegen.cnodes import Label
assert _test_args(Label('early_exit'))
def test_sympy__codegen__cnodes__PreDecrement():
from sympy.codegen.cnodes import PreDecrement
assert _test_args(PreDecrement(x))
def test_sympy__codegen__cnodes__PostDecrement():
from sympy.codegen.cnodes import PostDecrement
assert _test_args(PostDecrement(x))
def test_sympy__codegen__cnodes__PreIncrement():
from sympy.codegen.cnodes import PreIncrement
assert _test_args(PreIncrement(x))
def test_sympy__codegen__cnodes__PostIncrement():
from sympy.codegen.cnodes import PostIncrement
assert _test_args(PostIncrement(x))
def test_sympy__codegen__cnodes__struct():
from sympy.codegen.ast import real, Variable
from sympy.codegen.cnodes import struct
assert _test_args(struct(declarations=[
Variable(x, type=real),
Variable(y, type=real)
]))
def test_sympy__codegen__cnodes__union():
from sympy.codegen.ast import float32, int32, Variable
from sympy.codegen.cnodes import union
assert _test_args(union(declarations=[
Variable(x, type=float32),
Variable(y, type=int32)
]))
def test_sympy__codegen__cxxnodes__using():
from sympy.codegen.cxxnodes import using
assert _test_args(using('std::vector'))
assert _test_args(using('std::vector', 'vec'))
def test_sympy__codegen__fnodes__Program():
from sympy.codegen.fnodes import Program
assert _test_args(Program('foobar', []))
def test_sympy__codegen__fnodes__Module():
from sympy.codegen.fnodes import Module
assert _test_args(Module('foobar', [], []))
def test_sympy__codegen__fnodes__Subroutine():
from sympy.codegen.fnodes import Subroutine
x = symbols('x', real=True)
assert _test_args(Subroutine('foo', [x], []))
def test_sympy__codegen__fnodes__GoTo():
from sympy.codegen.fnodes import GoTo
assert _test_args(GoTo([10]))
assert _test_args(GoTo([10, 20], x > 1))
def test_sympy__codegen__fnodes__FortranReturn():
from sympy.codegen.fnodes import FortranReturn
assert _test_args(FortranReturn(10))
def test_sympy__codegen__fnodes__Extent():
from sympy.codegen.fnodes import Extent
assert _test_args(Extent())
assert _test_args(Extent(None))
assert _test_args(Extent(':'))
assert _test_args(Extent(-3, 4))
assert _test_args(Extent(x, y))
def test_sympy__codegen__fnodes__use_rename():
from sympy.codegen.fnodes import use_rename
assert _test_args(use_rename('loc', 'glob'))
def test_sympy__codegen__fnodes__use():
from sympy.codegen.fnodes import use
assert _test_args(use('modfoo', only='bar'))
def test_sympy__codegen__fnodes__SubroutineCall():
from sympy.codegen.fnodes import SubroutineCall
assert _test_args(SubroutineCall('foo', ['bar', 'baz']))
def test_sympy__codegen__fnodes__Do():
from sympy.codegen.fnodes import Do
assert _test_args(Do([], 'i', 1, 42))
def test_sympy__codegen__fnodes__ImpliedDoLoop():
from sympy.codegen.fnodes import ImpliedDoLoop
assert _test_args(ImpliedDoLoop('i', 'i', 1, 42))
def test_sympy__codegen__fnodes__ArrayConstructor():
from sympy.codegen.fnodes import ArrayConstructor
assert _test_args(ArrayConstructor([1, 2, 3]))
from sympy.codegen.fnodes import ImpliedDoLoop
idl = ImpliedDoLoop('i', 'i', 1, 42)
assert _test_args(ArrayConstructor([1, idl, 3]))
def test_sympy__codegen__fnodes__sum_():
from sympy.codegen.fnodes import sum_
assert _test_args(sum_('arr'))
def test_sympy__codegen__fnodes__product_():
from sympy.codegen.fnodes import product_
assert _test_args(product_('arr'))
@XFAIL
def test_sympy__combinatorics__graycode__GrayCode():
from sympy.combinatorics.graycode import GrayCode
# an integer is given and returned from GrayCode as the arg
assert _test_args(GrayCode(3, start='100'))
assert _test_args(GrayCode(3, rank=1))
def test_sympy__combinatorics__subsets__Subset():
from sympy.combinatorics.subsets import Subset
assert _test_args(Subset([0, 1], [0, 1, 2, 3]))
assert _test_args(Subset(['c', 'd'], ['a', 'b', 'c', 'd']))
@XFAIL
def test_sympy__combinatorics__permutations__Permutation():
from sympy.combinatorics.permutations import Permutation
assert _test_args(Permutation([0, 1, 2, 3]))
def test_sympy__combinatorics__perm_groups__PermutationGroup():
from sympy.combinatorics.permutations import Permutation
from sympy.combinatorics.perm_groups import PermutationGroup
assert _test_args(PermutationGroup([Permutation([0, 1])]))
def test_sympy__combinatorics__polyhedron__Polyhedron():
from sympy.combinatorics.permutations import Permutation
from sympy.combinatorics.polyhedron import Polyhedron
from sympy.abc import w, x, y, z
pgroup = [Permutation([[0, 1, 2], [3]]),
Permutation([[0, 1, 3], [2]]),
Permutation([[0, 2, 3], [1]]),
Permutation([[1, 2, 3], [0]]),
Permutation([[0, 1], [2, 3]]),
Permutation([[0, 2], [1, 3]]),
Permutation([[0, 3], [1, 2]]),
Permutation([[0, 1, 2, 3]])]
corners = [w, x, y, z]
faces = [(w, x, y), (w, y, z), (w, z, x), (x, y, z)]
assert _test_args(Polyhedron(corners, faces, pgroup))
@XFAIL
def test_sympy__combinatorics__prufer__Prufer():
from sympy.combinatorics.prufer import Prufer
assert _test_args(Prufer([[0, 1], [0, 2], [0, 3]], 4))
def test_sympy__combinatorics__partitions__Partition():
from sympy.combinatorics.partitions import Partition
assert _test_args(Partition([1]))
@XFAIL
def test_sympy__combinatorics__partitions__IntegerPartition():
from sympy.combinatorics.partitions import IntegerPartition
assert _test_args(IntegerPartition([1]))
def test_sympy__concrete__products__Product():
from sympy.concrete.products import Product
assert _test_args(Product(x, (x, 0, 10)))
assert _test_args(Product(x, (x, 0, y), (y, 0, 10)))
@SKIP("abstract Class")
def test_sympy__concrete__expr_with_limits__ExprWithLimits():
from sympy.concrete.expr_with_limits import ExprWithLimits
assert _test_args(ExprWithLimits(x, (x, 0, 10)))
assert _test_args(ExprWithLimits(x*y, (x, 0, 10.),(y,1.,3)))
@SKIP("abstract Class")
def test_sympy__concrete__expr_with_limits__AddWithLimits():
from sympy.concrete.expr_with_limits import AddWithLimits
assert _test_args(AddWithLimits(x, (x, 0, 10)))
assert _test_args(AddWithLimits(x*y, (x, 0, 10),(y,1,3)))
@SKIP("abstract Class")
def test_sympy__concrete__expr_with_intlimits__ExprWithIntLimits():
from sympy.concrete.expr_with_intlimits import ExprWithIntLimits
assert _test_args(ExprWithIntLimits(x, (x, 0, 10)))
assert _test_args(ExprWithIntLimits(x*y, (x, 0, 10),(y,1,3)))
def test_sympy__concrete__summations__Sum():
from sympy.concrete.summations import Sum
assert _test_args(Sum(x, (x, 0, 10)))
assert _test_args(Sum(x, (x, 0, y), (y, 0, 10)))
def test_sympy__core__add__Add():
from sympy.core.add import Add
assert _test_args(Add(x, y, z, 2))
def test_sympy__core__basic__Atom():
from sympy.core.basic import Atom
assert _test_args(Atom())
def test_sympy__core__basic__Basic():
from sympy.core.basic import Basic
assert _test_args(Basic())
def test_sympy__core__containers__Dict():
from sympy.core.containers import Dict
assert _test_args(Dict({x: y, y: z}))
def test_sympy__core__containers__Tuple():
from sympy.core.containers import Tuple
assert _test_args(Tuple(x, y, z, 2))
def test_sympy__core__expr__AtomicExpr():
from sympy.core.expr import AtomicExpr
assert _test_args(AtomicExpr())
def test_sympy__core__expr__Expr():
from sympy.core.expr import Expr
assert _test_args(Expr())
def test_sympy__core__expr__UnevaluatedExpr():
from sympy.core.expr import UnevaluatedExpr
from sympy.abc import x
assert _test_args(UnevaluatedExpr(x))
def test_sympy__core__function__Application():
from sympy.core.function import Application
assert _test_args(Application(1, 2, 3))
def test_sympy__core__function__AppliedUndef():
from sympy.core.function import AppliedUndef
assert _test_args(AppliedUndef(1, 2, 3))
def test_sympy__core__function__Derivative():
from sympy.core.function import Derivative
assert _test_args(Derivative(2, x, y, 3))
@SKIP("abstract class")
def test_sympy__core__function__Function():
pass
def test_sympy__core__function__Lambda():
assert _test_args(Lambda((x, y), x + y + z))
def test_sympy__core__function__Subs():
from sympy.core.function import Subs
assert _test_args(Subs(x + y, x, 2))
def test_sympy__core__function__WildFunction():
from sympy.core.function import WildFunction
assert _test_args(WildFunction('f'))
def test_sympy__core__mod__Mod():
from sympy.core.mod import Mod
assert _test_args(Mod(x, 2))
def test_sympy__core__mul__Mul():
from sympy.core.mul import Mul
assert _test_args(Mul(2, x, y, z))
def test_sympy__core__numbers__Catalan():
from sympy.core.numbers import Catalan
assert _test_args(Catalan())
def test_sympy__core__numbers__ComplexInfinity():
from sympy.core.numbers import ComplexInfinity
assert _test_args(ComplexInfinity())
def test_sympy__core__numbers__EulerGamma():
from sympy.core.numbers import EulerGamma
assert _test_args(EulerGamma())
def test_sympy__core__numbers__Exp1():
from sympy.core.numbers import Exp1
assert _test_args(Exp1())
def test_sympy__core__numbers__Float():
from sympy.core.numbers import Float
assert _test_args(Float(1.23))
def test_sympy__core__numbers__GoldenRatio():
from sympy.core.numbers import GoldenRatio
assert _test_args(GoldenRatio())
def test_sympy__core__numbers__TribonacciConstant():
from sympy.core.numbers import TribonacciConstant
assert _test_args(TribonacciConstant())
def test_sympy__core__numbers__Half():
from sympy.core.numbers import Half
assert _test_args(Half())
def test_sympy__core__numbers__ImaginaryUnit():
from sympy.core.numbers import ImaginaryUnit
assert _test_args(ImaginaryUnit())
def test_sympy__core__numbers__Infinity():
from sympy.core.numbers import Infinity
assert _test_args(Infinity())
def test_sympy__core__numbers__Integer():
from sympy.core.numbers import Integer
assert _test_args(Integer(7))
@SKIP("abstract class")
def test_sympy__core__numbers__IntegerConstant():
pass
def test_sympy__core__numbers__NaN():
from sympy.core.numbers import NaN
assert _test_args(NaN())
def test_sympy__core__numbers__NegativeInfinity():
from sympy.core.numbers import NegativeInfinity
assert _test_args(NegativeInfinity())
def test_sympy__core__numbers__NegativeOne():
from sympy.core.numbers import NegativeOne
assert _test_args(NegativeOne())
def test_sympy__core__numbers__Number():
from sympy.core.numbers import Number
assert _test_args(Number(1, 7))
def test_sympy__core__numbers__NumberSymbol():
from sympy.core.numbers import NumberSymbol
assert _test_args(NumberSymbol())
def test_sympy__core__numbers__One():
from sympy.core.numbers import One
assert _test_args(One())
def test_sympy__core__numbers__Pi():
from sympy.core.numbers import Pi
assert _test_args(Pi())
def test_sympy__core__numbers__Rational():
from sympy.core.numbers import Rational
assert _test_args(Rational(1, 7))
@SKIP("abstract class")
def test_sympy__core__numbers__RationalConstant():
pass
def test_sympy__core__numbers__Zero():
from sympy.core.numbers import Zero
assert _test_args(Zero())
@SKIP("abstract class")
def test_sympy__core__operations__AssocOp():
pass
@SKIP("abstract class")
def test_sympy__core__operations__LatticeOp():
pass
def test_sympy__core__power__Pow():
from sympy.core.power import Pow
assert _test_args(Pow(x, 2))
def test_sympy__algebras__quaternion__Quaternion():
from sympy.algebras.quaternion import Quaternion
assert _test_args(Quaternion(x, 1, 2, 3))
def test_sympy__core__relational__Equality():
from sympy.core.relational import Equality
assert _test_args(Equality(x, 2))
def test_sympy__core__relational__GreaterThan():
from sympy.core.relational import GreaterThan
assert _test_args(GreaterThan(x, 2))
def test_sympy__core__relational__LessThan():
from sympy.core.relational import LessThan
assert _test_args(LessThan(x, 2))
@SKIP("abstract class")
def test_sympy__core__relational__Relational():
pass
def test_sympy__core__relational__StrictGreaterThan():
from sympy.core.relational import StrictGreaterThan
assert _test_args(StrictGreaterThan(x, 2))
def test_sympy__core__relational__StrictLessThan():
from sympy.core.relational import StrictLessThan
assert _test_args(StrictLessThan(x, 2))
def test_sympy__core__relational__Unequality():
from sympy.core.relational import Unequality
assert _test_args(Unequality(x, 2))
def test_sympy__sandbox__indexed_integrals__IndexedIntegral():
from sympy.tensor import IndexedBase, Idx
from sympy.sandbox.indexed_integrals import IndexedIntegral
A = IndexedBase('A')
i, j = symbols('i j', integer=True)
a1, a2 = symbols('a1:3', cls=Idx)
assert _test_args(IndexedIntegral(A[a1], A[a2]))
assert _test_args(IndexedIntegral(A[i], A[j]))
def test_sympy__calculus__util__AccumulationBounds():
from sympy.calculus.util import AccumulationBounds
assert _test_args(AccumulationBounds(0, 1))
def test_sympy__sets__ordinals__OmegaPower():
from sympy.sets.ordinals import OmegaPower
assert _test_args(OmegaPower(1, 1))
def test_sympy__sets__ordinals__Ordinal():
from sympy.sets.ordinals import Ordinal, OmegaPower
assert _test_args(Ordinal(OmegaPower(2, 1)))
def test_sympy__sets__ordinals__OrdinalOmega():
from sympy.sets.ordinals import OrdinalOmega
assert _test_args(OrdinalOmega())
def test_sympy__sets__ordinals__OrdinalZero():
from sympy.sets.ordinals import OrdinalZero
assert _test_args(OrdinalZero())
def test_sympy__sets__sets__EmptySet():
from sympy.sets.sets import EmptySet
assert _test_args(EmptySet())
def test_sympy__sets__sets__UniversalSet():
from sympy.sets.sets import UniversalSet
assert _test_args(UniversalSet())
def test_sympy__sets__sets__FiniteSet():
from sympy.sets.sets import FiniteSet
assert _test_args(FiniteSet(x, y, z))
def test_sympy__sets__sets__Interval():
from sympy.sets.sets import Interval
assert _test_args(Interval(0, 1))
def test_sympy__sets__sets__ProductSet():
from sympy.sets.sets import ProductSet, Interval
assert _test_args(ProductSet(Interval(0, 1), Interval(0, 1)))
@SKIP("does it make sense to test this?")
def test_sympy__sets__sets__Set():
from sympy.sets.sets import Set
assert _test_args(Set())
def test_sympy__sets__sets__Intersection():
from sympy.sets.sets import Intersection, Interval
assert _test_args(Intersection(Interval(0, 3), Interval(2, 4),
evaluate=False))
def test_sympy__sets__sets__Union():
from sympy.sets.sets import Union, Interval
assert _test_args(Union(Interval(0, 1), Interval(2, 3)))
def test_sympy__sets__sets__Complement():
from sympy.sets.sets import Complement
assert _test_args(Complement(Interval(0, 2), Interval(0, 1)))
def test_sympy__sets__sets__SymmetricDifference():
from sympy.sets.sets import FiniteSet, SymmetricDifference
assert _test_args(SymmetricDifference(FiniteSet(1, 2, 3), \
FiniteSet(2, 3, 4)))
def test_sympy__core__trace__Tr():
from sympy.core.trace import Tr
a, b = symbols('a b')
assert _test_args(Tr(a + b))
def test_sympy__sets__setexpr__SetExpr():
from sympy.sets.setexpr import SetExpr
assert _test_args(SetExpr(Interval(0, 1)))
def test_sympy__sets__fancysets__Naturals():
from sympy.sets.fancysets import Naturals
assert _test_args(Naturals())
def test_sympy__sets__fancysets__Naturals0():
from sympy.sets.fancysets import Naturals0
assert _test_args(Naturals0())
def test_sympy__sets__fancysets__Integers():
from sympy.sets.fancysets import Integers
assert _test_args(Integers())
def test_sympy__sets__fancysets__Reals():
from sympy.sets.fancysets import Reals
assert _test_args(Reals())
def test_sympy__sets__fancysets__Complexes():
from sympy.sets.fancysets import Complexes
assert _test_args(Complexes())
def test_sympy__sets__fancysets__ComplexRegion():
from sympy.sets.fancysets import ComplexRegion
from sympy import S
from sympy.sets import Interval
a = Interval(0, 1)
b = Interval(2, 3)
theta = Interval(0, 2*S.Pi)
assert _test_args(ComplexRegion(a*b))
assert _test_args(ComplexRegion(a*theta, polar=True))
def test_sympy__sets__fancysets__ImageSet():
from sympy.sets.fancysets import ImageSet
from sympy import S, Symbol
x = Symbol('x')
assert _test_args(ImageSet(Lambda(x, x**2), S.Naturals))
def test_sympy__sets__fancysets__Range():
from sympy.sets.fancysets import Range
assert _test_args(Range(1, 5, 1))
def test_sympy__sets__conditionset__ConditionSet():
from sympy.sets.conditionset import ConditionSet
from sympy import S, Symbol
x = Symbol('x')
assert _test_args(ConditionSet(x, Eq(x**2, 1), S.Reals))
def test_sympy__sets__contains__Contains():
from sympy.sets.fancysets import Range
from sympy.sets.contains import Contains
assert _test_args(Contains(x, Range(0, 10, 2)))
# STATS
from sympy.stats.crv_types import NormalDistribution
nd = NormalDistribution(0, 1)
from sympy.stats.frv_types import DieDistribution
die = DieDistribution(6)
def test_sympy__stats__crv__ContinuousDomain():
from sympy.stats.crv import ContinuousDomain
assert _test_args(ContinuousDomain({x}, Interval(-oo, oo)))
def test_sympy__stats__crv__SingleContinuousDomain():
from sympy.stats.crv import SingleContinuousDomain
assert _test_args(SingleContinuousDomain(x, Interval(-oo, oo)))
def test_sympy__stats__crv__ProductContinuousDomain():
from sympy.stats.crv import SingleContinuousDomain, ProductContinuousDomain
D = SingleContinuousDomain(x, Interval(-oo, oo))
E = SingleContinuousDomain(y, Interval(0, oo))
assert _test_args(ProductContinuousDomain(D, E))
def test_sympy__stats__crv__ConditionalContinuousDomain():
from sympy.stats.crv import (SingleContinuousDomain,
ConditionalContinuousDomain)
D = SingleContinuousDomain(x, Interval(-oo, oo))
assert _test_args(ConditionalContinuousDomain(D, x > 0))
def test_sympy__stats__crv__ContinuousPSpace():
from sympy.stats.crv import ContinuousPSpace, SingleContinuousDomain
D = SingleContinuousDomain(x, Interval(-oo, oo))
assert _test_args(ContinuousPSpace(D, nd))
def test_sympy__stats__crv__SingleContinuousPSpace():
from sympy.stats.crv import SingleContinuousPSpace
assert _test_args(SingleContinuousPSpace(x, nd))
@SKIP("abstract class")
def test_sympy__stats__crv__SingleContinuousDistribution():
pass
def test_sympy__stats__drv__SingleDiscreteDomain():
from sympy.stats.drv import SingleDiscreteDomain
assert _test_args(SingleDiscreteDomain(x, S.Naturals))
def test_sympy__stats__drv__ProductDiscreteDomain():
from sympy.stats.drv import SingleDiscreteDomain, ProductDiscreteDomain
X = SingleDiscreteDomain(x, S.Naturals)
Y = SingleDiscreteDomain(y, S.Integers)
assert _test_args(ProductDiscreteDomain(X, Y))
def test_sympy__stats__drv__SingleDiscretePSpace():
from sympy.stats.drv import SingleDiscretePSpace
from sympy.stats.drv_types import PoissonDistribution
assert _test_args(SingleDiscretePSpace(x, PoissonDistribution(1)))
def test_sympy__stats__drv__DiscretePSpace():
from sympy.stats.drv import DiscretePSpace, SingleDiscreteDomain
density = Lambda(x, 2**(-x))
domain = SingleDiscreteDomain(x, S.Naturals)
assert _test_args(DiscretePSpace(domain, density))
def test_sympy__stats__drv__ConditionalDiscreteDomain():
from sympy.stats.drv import ConditionalDiscreteDomain, SingleDiscreteDomain
X = SingleDiscreteDomain(x, S.Naturals0)
assert _test_args(ConditionalDiscreteDomain(X, x > 2))
def test_sympy__stats__joint_rv__JointPSpace():
from sympy.stats.joint_rv import JointPSpace, JointDistribution
assert _test_args(JointPSpace('X', JointDistribution(1)))
def test_sympy__stats__joint_rv__JointRandomSymbol():
from sympy.stats.joint_rv import JointRandomSymbol
assert _test_args(JointRandomSymbol(x))
def test_sympy__stats__joint_rv__JointDistributionHandmade():
from sympy import Indexed
from sympy.stats.joint_rv import JointDistributionHandmade
x1, x2 = (Indexed('x', i) for i in (1, 2))
assert _test_args(JointDistributionHandmade(x1 + x2, S.Reals**2))
def test_sympy__stats__joint_rv__MarginalDistribution():
from sympy.stats.rv import RandomSymbol
from sympy.stats.joint_rv import MarginalDistribution
r = RandomSymbol(S('r'))
assert _test_args(MarginalDistribution(r, (r,)))
def test_sympy__stats__joint_rv__CompoundDistribution():
from sympy.stats.joint_rv import CompoundDistribution
from sympy.stats.drv_types import PoissonDistribution
r = PoissonDistribution(x)
assert _test_args(CompoundDistribution(PoissonDistribution(r)))
@SKIP("abstract class")
def test_sympy__stats__drv__SingleDiscreteDistribution():
pass
@SKIP("abstract class")
def test_sympy__stats__drv__DiscreteDistribution():
pass
@SKIP("abstract class")
def test_sympy__stats__drv__DiscreteDomain():
pass
def test_sympy__stats__rv__RandomDomain():
from sympy.stats.rv import RandomDomain
from sympy.sets.sets import FiniteSet
assert _test_args(RandomDomain(FiniteSet(x), FiniteSet(1, 2, 3)))
def test_sympy__stats__rv__SingleDomain():
from sympy.stats.rv import SingleDomain
from sympy.sets.sets import FiniteSet
assert _test_args(SingleDomain(x, FiniteSet(1, 2, 3)))
def test_sympy__stats__rv__ConditionalDomain():
from sympy.stats.rv import ConditionalDomain, RandomDomain
from sympy.sets.sets import FiniteSet
D = RandomDomain(FiniteSet(x), FiniteSet(1, 2))
assert _test_args(ConditionalDomain(D, x > 1))
def test_sympy__stats__rv__PSpace():
from sympy.stats.rv import PSpace, RandomDomain
from sympy import FiniteSet
D = RandomDomain(FiniteSet(x), FiniteSet(1, 2, 3, 4, 5, 6))
assert _test_args(PSpace(D, die))
@SKIP("abstract Class")
def test_sympy__stats__rv__SinglePSpace():
pass
def test_sympy__stats__rv__RandomSymbol():
from sympy.stats.rv import RandomSymbol
from sympy.stats.crv import SingleContinuousPSpace
A = SingleContinuousPSpace(x, nd)
assert _test_args(RandomSymbol(x, A))
@SKIP("abstract Class")
def test_sympy__stats__rv__ProductPSpace():
pass
def test_sympy__stats__rv__IndependentProductPSpace():
from sympy.stats.rv import IndependentProductPSpace
from sympy.stats.crv import SingleContinuousPSpace
A = SingleContinuousPSpace(x, nd)
B = SingleContinuousPSpace(y, nd)
assert _test_args(IndependentProductPSpace(A, B))
def test_sympy__stats__rv__ProductDomain():
from sympy.stats.rv import ProductDomain, SingleDomain
D = SingleDomain(x, Interval(-oo, oo))
E = SingleDomain(y, Interval(0, oo))
assert _test_args(ProductDomain(D, E))
def test_sympy__stats__symbolic_probability__Probability():
from sympy.stats.symbolic_probability import Probability
from sympy.stats import Normal
X = Normal('X', 0, 1)
assert _test_args(Probability(X > 0))
def test_sympy__stats__symbolic_probability__Expectation():
from sympy.stats.symbolic_probability import Expectation
from sympy.stats import Normal
X = Normal('X', 0, 1)
assert _test_args(Expectation(X > 0))
def test_sympy__stats__symbolic_probability__Covariance():
from sympy.stats.symbolic_probability import Covariance
from sympy.stats import Normal
X = Normal('X', 0, 1)
Y = Normal('Y', 0, 3)
assert _test_args(Covariance(X, Y))
def test_sympy__stats__symbolic_probability__Variance():
from sympy.stats.symbolic_probability import Variance
from sympy.stats import Normal
X = Normal('X', 0, 1)
assert _test_args(Variance(X))
def test_sympy__stats__frv_types__DiscreteUniformDistribution():
from sympy.stats.frv_types import DiscreteUniformDistribution
from sympy.core.containers import Tuple
assert _test_args(DiscreteUniformDistribution(Tuple(*list(range(6)))))
def test_sympy__stats__frv_types__DieDistribution():
assert _test_args(die)
def test_sympy__stats__frv_types__BernoulliDistribution():
from sympy.stats.frv_types import BernoulliDistribution
assert _test_args(BernoulliDistribution(S.Half, 0, 1))
def test_sympy__stats__frv_types__BinomialDistribution():
from sympy.stats.frv_types import BinomialDistribution
assert _test_args(BinomialDistribution(5, S.Half, 1, 0))
def test_sympy__stats__frv_types__HypergeometricDistribution():
from sympy.stats.frv_types import HypergeometricDistribution
assert _test_args(HypergeometricDistribution(10, 5, 3))
def test_sympy__stats__frv_types__RademacherDistribution():
from sympy.stats.frv_types import RademacherDistribution
assert _test_args(RademacherDistribution())
def test_sympy__stats__frv__FiniteDomain():
from sympy.stats.frv import FiniteDomain
assert _test_args(FiniteDomain({(x, 1), (x, 2)})) # x can be 1 or 2
def test_sympy__stats__frv__SingleFiniteDomain():
from sympy.stats.frv import SingleFiniteDomain
assert _test_args(SingleFiniteDomain(x, {1, 2})) # x can be 1 or 2
def test_sympy__stats__frv__ProductFiniteDomain():
from sympy.stats.frv import SingleFiniteDomain, ProductFiniteDomain
xd = SingleFiniteDomain(x, {1, 2})
yd = SingleFiniteDomain(y, {1, 2})
assert _test_args(ProductFiniteDomain(xd, yd))
def test_sympy__stats__frv__ConditionalFiniteDomain():
from sympy.stats.frv import SingleFiniteDomain, ConditionalFiniteDomain
xd = SingleFiniteDomain(x, {1, 2})
assert _test_args(ConditionalFiniteDomain(xd, x > 1))
def test_sympy__stats__frv__FinitePSpace():
from sympy.stats.frv import FinitePSpace, SingleFiniteDomain
xd = SingleFiniteDomain(x, {1, 2, 3, 4, 5, 6})
p = 1.0/6
xd = SingleFiniteDomain(x, {1, 2})
assert _test_args(FinitePSpace(xd, {(x, 1): S.Half, (x, 2): S.Half}))
def test_sympy__stats__frv__SingleFinitePSpace():
from sympy.stats.frv import SingleFinitePSpace
from sympy import Symbol
assert _test_args(SingleFinitePSpace(Symbol('x'), die))
def test_sympy__stats__frv__ProductFinitePSpace():
from sympy.stats.frv import SingleFinitePSpace, ProductFinitePSpace
from sympy import Symbol
xp = SingleFinitePSpace(Symbol('x'), die)
yp = SingleFinitePSpace(Symbol('y'), die)
assert _test_args(ProductFinitePSpace(xp, yp))
@SKIP("abstract class")
def test_sympy__stats__frv__SingleFiniteDistribution():
pass
@SKIP("abstract class")
def test_sympy__stats__crv__ContinuousDistribution():
pass
def test_sympy__stats__frv_types__FiniteDistributionHandmade():
from sympy.stats.frv_types import FiniteDistributionHandmade
assert _test_args(FiniteDistributionHandmade({1: 1}))
def test_sympy__stats__crv__ContinuousDistributionHandmade():
from sympy.stats.crv import ContinuousDistributionHandmade
from sympy import Symbol, Interval
assert _test_args(ContinuousDistributionHandmade(Symbol('x'),
Interval(0, 2)))
def test_sympy__stats__drv__DiscreteDistributionHandmade():
from sympy.stats.drv import DiscreteDistributionHandmade
assert _test_args(DiscreteDistributionHandmade(x, S.Naturals))
def test_sympy__stats__rv__Density():
from sympy.stats.rv import Density
from sympy.stats.crv_types import Normal
assert _test_args(Density(Normal('x', 0, 1)))
def test_sympy__stats__crv_types__ArcsinDistribution():
from sympy.stats.crv_types import ArcsinDistribution
assert _test_args(ArcsinDistribution(0, 1))
def test_sympy__stats__crv_types__BeniniDistribution():
from sympy.stats.crv_types import BeniniDistribution
assert _test_args(BeniniDistribution(1, 1, 1))
def test_sympy__stats__crv_types__BetaDistribution():
from sympy.stats.crv_types import BetaDistribution
assert _test_args(BetaDistribution(1, 1))
def test_sympy__stats__crv_types__BetaPrimeDistribution():
from sympy.stats.crv_types import BetaPrimeDistribution
assert _test_args(BetaPrimeDistribution(1, 1))
def test_sympy__stats__crv_types__CauchyDistribution():
from sympy.stats.crv_types import CauchyDistribution
assert _test_args(CauchyDistribution(0, 1))
def test_sympy__stats__crv_types__ChiDistribution():
from sympy.stats.crv_types import ChiDistribution
assert _test_args(ChiDistribution(1))
def test_sympy__stats__crv_types__ChiNoncentralDistribution():
from sympy.stats.crv_types import ChiNoncentralDistribution
assert _test_args(ChiNoncentralDistribution(1,1))
def test_sympy__stats__crv_types__ChiSquaredDistribution():
from sympy.stats.crv_types import ChiSquaredDistribution
assert _test_args(ChiSquaredDistribution(1))
def test_sympy__stats__crv_types__DagumDistribution():
from sympy.stats.crv_types import DagumDistribution
assert _test_args(DagumDistribution(1, 1, 1))
def test_sympy__stats__crv_types__ExponentialDistribution():
from sympy.stats.crv_types import ExponentialDistribution
assert _test_args(ExponentialDistribution(1))
def test_sympy__stats__crv_types__FDistributionDistribution():
from sympy.stats.crv_types import FDistributionDistribution
assert _test_args(FDistributionDistribution(1, 1))
def test_sympy__stats__crv_types__FisherZDistribution():
from sympy.stats.crv_types import FisherZDistribution
assert _test_args(FisherZDistribution(1, 1))
def test_sympy__stats__crv_types__FrechetDistribution():
from sympy.stats.crv_types import FrechetDistribution
assert _test_args(FrechetDistribution(1, 1, 1))
def test_sympy__stats__crv_types__GammaInverseDistribution():
from sympy.stats.crv_types import GammaInverseDistribution
assert _test_args(GammaInverseDistribution(1, 1))
def test_sympy__stats__crv_types__GammaDistribution():
from sympy.stats.crv_types import GammaDistribution
assert _test_args(GammaDistribution(1, 1))
def test_sympy__stats__crv_types__GumbelDistribution():
from sympy.stats.crv_types import GumbelDistribution
assert _test_args(GumbelDistribution(1, 1))
def test_sympy__stats__crv_types__GompertzDistribution():
from sympy.stats.crv_types import GompertzDistribution
assert _test_args(GompertzDistribution(1, 1))
def test_sympy__stats__crv_types__KumaraswamyDistribution():
from sympy.stats.crv_types import KumaraswamyDistribution
assert _test_args(KumaraswamyDistribution(1, 1))
def test_sympy__stats__crv_types__LaplaceDistribution():
from sympy.stats.crv_types import LaplaceDistribution
assert _test_args(LaplaceDistribution(0, 1))
def test_sympy__stats__crv_types__LogisticDistribution():
from sympy.stats.crv_types import LogisticDistribution
assert _test_args(LogisticDistribution(0, 1))
def test_sympy__stats__crv_types__LogNormalDistribution():
from sympy.stats.crv_types import LogNormalDistribution
assert _test_args(LogNormalDistribution(0, 1))
def test_sympy__stats__crv_types__MaxwellDistribution():
from sympy.stats.crv_types import MaxwellDistribution
assert _test_args(MaxwellDistribution(1))
def test_sympy__stats__crv_types__NakagamiDistribution():
from sympy.stats.crv_types import NakagamiDistribution
assert _test_args(NakagamiDistribution(1, 1))
def test_sympy__stats__crv_types__NormalDistribution():
from sympy.stats.crv_types import NormalDistribution
assert _test_args(NormalDistribution(0, 1))
def test_sympy__stats__crv_types__ParetoDistribution():
from sympy.stats.crv_types import ParetoDistribution
assert _test_args(ParetoDistribution(1, 1))
def test_sympy__stats__crv_types__QuadraticUDistribution():
from sympy.stats.crv_types import QuadraticUDistribution
assert _test_args(QuadraticUDistribution(1, 2))
def test_sympy__stats__crv_types__RaisedCosineDistribution():
from sympy.stats.crv_types import RaisedCosineDistribution
assert _test_args(RaisedCosineDistribution(1, 1))
def test_sympy__stats__crv_types__RayleighDistribution():
from sympy.stats.crv_types import RayleighDistribution
assert _test_args(RayleighDistribution(1))
def test_sympy__stats__crv_types__ShiftedGompertzDistribution():
from sympy.stats.crv_types import ShiftedGompertzDistribution
assert _test_args(ShiftedGompertzDistribution(1, 1))
def test_sympy__stats__crv_types__StudentTDistribution():
from sympy.stats.crv_types import StudentTDistribution
assert _test_args(StudentTDistribution(1))
def test_sympy__stats__crv_types__TrapezoidalDistribution():
from sympy.stats.crv_types import TrapezoidalDistribution
assert _test_args(TrapezoidalDistribution(1, 2, 3, 4))
def test_sympy__stats__crv_types__TriangularDistribution():
from sympy.stats.crv_types import TriangularDistribution
assert _test_args(TriangularDistribution(-1, 0, 1))
def test_sympy__stats__crv_types__UniformDistribution():
from sympy.stats.crv_types import UniformDistribution
assert _test_args(UniformDistribution(0, 1))
def test_sympy__stats__crv_types__UniformSumDistribution():
from sympy.stats.crv_types import UniformSumDistribution
assert _test_args(UniformSumDistribution(1))
def test_sympy__stats__crv_types__VonMisesDistribution():
from sympy.stats.crv_types import VonMisesDistribution
assert _test_args(VonMisesDistribution(1, 1))
def test_sympy__stats__crv_types__WeibullDistribution():
from sympy.stats.crv_types import WeibullDistribution
assert _test_args(WeibullDistribution(1, 1))
def test_sympy__stats__crv_types__WignerSemicircleDistribution():
from sympy.stats.crv_types import WignerSemicircleDistribution
assert _test_args(WignerSemicircleDistribution(1))
def test_sympy__stats__drv_types__GeometricDistribution():
from sympy.stats.drv_types import GeometricDistribution
assert _test_args(GeometricDistribution(.5))
def test_sympy__stats__drv_types__LogarithmicDistribution():
from sympy.stats.drv_types import LogarithmicDistribution
assert _test_args(LogarithmicDistribution(.5))
def test_sympy__stats__drv_types__NegativeBinomialDistribution():
from sympy.stats.drv_types import NegativeBinomialDistribution
assert _test_args(NegativeBinomialDistribution(.5, .5))
def test_sympy__stats__drv_types__PoissonDistribution():
from sympy.stats.drv_types import PoissonDistribution
assert _test_args(PoissonDistribution(1))
def test_sympy__stats__drv_types__YuleSimonDistribution():
from sympy.stats.drv_types import YuleSimonDistribution
assert _test_args(YuleSimonDistribution(.5))
def test_sympy__stats__drv_types__ZetaDistribution():
from sympy.stats.drv_types import ZetaDistribution
assert _test_args(ZetaDistribution(1.5))
def test_sympy__stats__joint_rv__JointDistribution():
from sympy.stats.joint_rv import JointDistribution
assert _test_args(JointDistribution(1, 2, 3, 4))
def test_sympy__stats__joint_rv_types__MultivariateNormalDistribution():
from sympy.stats.joint_rv_types import MultivariateNormalDistribution
assert _test_args(
MultivariateNormalDistribution([0, 1], [[1, 0],[0, 1]]))
def test_sympy__stats__joint_rv_types__MultivariateLaplaceDistribution():
from sympy.stats.joint_rv_types import MultivariateLaplaceDistribution
assert _test_args(MultivariateLaplaceDistribution([0, 1], [[1, 0],[0, 1]]))
def test_sympy__stats__joint_rv_types__MultivariateTDistribution():
from sympy.stats.joint_rv_types import MultivariateTDistribution
assert _test_args(MultivariateTDistribution([0, 1], [[1, 0],[0, 1]], 1))
def test_sympy__stats__joint_rv_types__NormalGammaDistribution():
from sympy.stats.joint_rv_types import NormalGammaDistribution
assert _test_args(NormalGammaDistribution(1, 2, 3, 4))
def test_sympy__core__symbol__Dummy():
from sympy.core.symbol import Dummy
assert _test_args(Dummy('t'))
def test_sympy__core__symbol__Symbol():
from sympy.core.symbol import Symbol
assert _test_args(Symbol('t'))
def test_sympy__core__symbol__Wild():
from sympy.core.symbol import Wild
assert _test_args(Wild('x', exclude=[x]))
@SKIP("abstract class")
def test_sympy__functions__combinatorial__factorials__CombinatorialFunction():
pass
def test_sympy__functions__combinatorial__factorials__FallingFactorial():
from sympy.functions.combinatorial.factorials import FallingFactorial
assert _test_args(FallingFactorial(2, x))
def test_sympy__functions__combinatorial__factorials__MultiFactorial():
from sympy.functions.combinatorial.factorials import MultiFactorial
assert _test_args(MultiFactorial(x))
def test_sympy__functions__combinatorial__factorials__RisingFactorial():
from sympy.functions.combinatorial.factorials import RisingFactorial
assert _test_args(RisingFactorial(2, x))
def test_sympy__functions__combinatorial__factorials__binomial():
from sympy.functions.combinatorial.factorials import binomial
assert _test_args(binomial(2, x))
def test_sympy__functions__combinatorial__factorials__subfactorial():
from sympy.functions.combinatorial.factorials import subfactorial
assert _test_args(subfactorial(1))
def test_sympy__functions__combinatorial__factorials__factorial():
from sympy.functions.combinatorial.factorials import factorial
assert _test_args(factorial(x))
def test_sympy__functions__combinatorial__factorials__factorial2():
from sympy.functions.combinatorial.factorials import factorial2
assert _test_args(factorial2(x))
def test_sympy__functions__combinatorial__numbers__bell():
from sympy.functions.combinatorial.numbers import bell
assert _test_args(bell(x, y))
def test_sympy__functions__combinatorial__numbers__bernoulli():
from sympy.functions.combinatorial.numbers import bernoulli
assert _test_args(bernoulli(x))
def test_sympy__functions__combinatorial__numbers__catalan():
from sympy.functions.combinatorial.numbers import catalan
assert _test_args(catalan(x))
def test_sympy__functions__combinatorial__numbers__genocchi():
from sympy.functions.combinatorial.numbers import genocchi
assert _test_args(genocchi(x))
def test_sympy__functions__combinatorial__numbers__euler():
from sympy.functions.combinatorial.numbers import euler
assert _test_args(euler(x))
def test_sympy__functions__combinatorial__numbers__carmichael():
from sympy.functions.combinatorial.numbers import carmichael
assert _test_args(carmichael(x))
def test_sympy__functions__combinatorial__numbers__fibonacci():
from sympy.functions.combinatorial.numbers import fibonacci
assert _test_args(fibonacci(x))
def test_sympy__functions__combinatorial__numbers__tribonacci():
from sympy.functions.combinatorial.numbers import tribonacci
assert _test_args(tribonacci(x))
def test_sympy__functions__combinatorial__numbers__harmonic():
from sympy.functions.combinatorial.numbers import harmonic
assert _test_args(harmonic(x, 2))
def test_sympy__functions__combinatorial__numbers__lucas():
from sympy.functions.combinatorial.numbers import lucas
assert _test_args(lucas(x))
def test_sympy__functions__combinatorial__numbers__partition():
from sympy.core.symbol import Symbol
from sympy.functions.combinatorial.numbers import partition
assert _test_args(partition(Symbol('a', integer=True)))
def test_sympy__functions__elementary__complexes__Abs():
from sympy.functions.elementary.complexes import Abs
assert _test_args(Abs(x))
def test_sympy__functions__elementary__complexes__adjoint():
from sympy.functions.elementary.complexes import adjoint
assert _test_args(adjoint(x))
def test_sympy__functions__elementary__complexes__arg():
from sympy.functions.elementary.complexes import arg
assert _test_args(arg(x))
def test_sympy__functions__elementary__complexes__conjugate():
from sympy.functions.elementary.complexes import conjugate
assert _test_args(conjugate(x))
def test_sympy__functions__elementary__complexes__im():
from sympy.functions.elementary.complexes import im
assert _test_args(im(x))
def test_sympy__functions__elementary__complexes__re():
from sympy.functions.elementary.complexes import re
assert _test_args(re(x))
def test_sympy__functions__elementary__complexes__sign():
from sympy.functions.elementary.complexes import sign
assert _test_args(sign(x))
def test_sympy__functions__elementary__complexes__polar_lift():
from sympy.functions.elementary.complexes import polar_lift
assert _test_args(polar_lift(x))
def test_sympy__functions__elementary__complexes__periodic_argument():
from sympy.functions.elementary.complexes import periodic_argument
assert _test_args(periodic_argument(x, y))
def test_sympy__functions__elementary__complexes__principal_branch():
from sympy.functions.elementary.complexes import principal_branch
assert _test_args(principal_branch(x, y))
def test_sympy__functions__elementary__complexes__transpose():
from sympy.functions.elementary.complexes import transpose
assert _test_args(transpose(x))
def test_sympy__functions__elementary__exponential__LambertW():
from sympy.functions.elementary.exponential import LambertW
assert _test_args(LambertW(2))
@SKIP("abstract class")
def test_sympy__functions__elementary__exponential__ExpBase():
pass
def test_sympy__functions__elementary__exponential__exp():
from sympy.functions.elementary.exponential import exp
assert _test_args(exp(2))
def test_sympy__functions__elementary__exponential__exp_polar():
from sympy.functions.elementary.exponential import exp_polar
assert _test_args(exp_polar(2))
def test_sympy__functions__elementary__exponential__log():
from sympy.functions.elementary.exponential import log
assert _test_args(log(2))
@SKIP("abstract class")
def test_sympy__functions__elementary__hyperbolic__HyperbolicFunction():
pass
@SKIP("abstract class")
def test_sympy__functions__elementary__hyperbolic__ReciprocalHyperbolicFunction():
pass
@SKIP("abstract class")
def test_sympy__functions__elementary__hyperbolic__InverseHyperbolicFunction():
pass
def test_sympy__functions__elementary__hyperbolic__acosh():
from sympy.functions.elementary.hyperbolic import acosh
assert _test_args(acosh(2))
def test_sympy__functions__elementary__hyperbolic__acoth():
from sympy.functions.elementary.hyperbolic import acoth
assert _test_args(acoth(2))
def test_sympy__functions__elementary__hyperbolic__asinh():
from sympy.functions.elementary.hyperbolic import asinh
assert _test_args(asinh(2))
def test_sympy__functions__elementary__hyperbolic__atanh():
from sympy.functions.elementary.hyperbolic import atanh
assert _test_args(atanh(2))
def test_sympy__functions__elementary__hyperbolic__asech():
from sympy.functions.elementary.hyperbolic import asech
assert _test_args(asech(2))
def test_sympy__functions__elementary__hyperbolic__acsch():
from sympy.functions.elementary.hyperbolic import acsch
assert _test_args(acsch(2))
def test_sympy__functions__elementary__hyperbolic__cosh():
from sympy.functions.elementary.hyperbolic import cosh
assert _test_args(cosh(2))
def test_sympy__functions__elementary__hyperbolic__coth():
from sympy.functions.elementary.hyperbolic import coth
assert _test_args(coth(2))
def test_sympy__functions__elementary__hyperbolic__csch():
from sympy.functions.elementary.hyperbolic import csch
assert _test_args(csch(2))
def test_sympy__functions__elementary__hyperbolic__sech():
from sympy.functions.elementary.hyperbolic import sech
assert _test_args(sech(2))
def test_sympy__functions__elementary__hyperbolic__sinh():
from sympy.functions.elementary.hyperbolic import sinh
assert _test_args(sinh(2))
def test_sympy__functions__elementary__hyperbolic__tanh():
from sympy.functions.elementary.hyperbolic import tanh
assert _test_args(tanh(2))
@SKIP("does this work at all?")
def test_sympy__functions__elementary__integers__RoundFunction():
from sympy.functions.elementary.integers import RoundFunction
assert _test_args(RoundFunction())
def test_sympy__functions__elementary__integers__ceiling():
from sympy.functions.elementary.integers import ceiling
assert _test_args(ceiling(x))
def test_sympy__functions__elementary__integers__floor():
from sympy.functions.elementary.integers import floor
assert _test_args(floor(x))
def test_sympy__functions__elementary__integers__frac():
from sympy.functions.elementary.integers import frac
assert _test_args(frac(x))
def test_sympy__functions__elementary__miscellaneous__IdentityFunction():
from sympy.functions.elementary.miscellaneous import IdentityFunction
assert _test_args(IdentityFunction())
def test_sympy__functions__elementary__miscellaneous__Max():
from sympy.functions.elementary.miscellaneous import Max
assert _test_args(Max(x, 2))
def test_sympy__functions__elementary__miscellaneous__Min():
from sympy.functions.elementary.miscellaneous import Min
assert _test_args(Min(x, 2))
@SKIP("abstract class")
def test_sympy__functions__elementary__miscellaneous__MinMaxBase():
pass
def test_sympy__functions__elementary__piecewise__ExprCondPair():
from sympy.functions.elementary.piecewise import ExprCondPair
assert _test_args(ExprCondPair(1, True))
def test_sympy__functions__elementary__piecewise__Piecewise():
from sympy.functions.elementary.piecewise import Piecewise
assert _test_args(Piecewise((1, x >= 0), (0, True)))
@SKIP("abstract class")
def test_sympy__functions__elementary__trigonometric__TrigonometricFunction():
pass
@SKIP("abstract class")
def test_sympy__functions__elementary__trigonometric__ReciprocalTrigonometricFunction():
pass
@SKIP("abstract class")
def test_sympy__functions__elementary__trigonometric__InverseTrigonometricFunction():
pass
def test_sympy__functions__elementary__trigonometric__acos():
from sympy.functions.elementary.trigonometric import acos
assert _test_args(acos(2))
def test_sympy__functions__elementary__trigonometric__acot():
from sympy.functions.elementary.trigonometric import acot
assert _test_args(acot(2))
def test_sympy__functions__elementary__trigonometric__asin():
from sympy.functions.elementary.trigonometric import asin
assert _test_args(asin(2))
def test_sympy__functions__elementary__trigonometric__asec():
from sympy.functions.elementary.trigonometric import asec
assert _test_args(asec(2))
def test_sympy__functions__elementary__trigonometric__acsc():
from sympy.functions.elementary.trigonometric import acsc
assert _test_args(acsc(2))
def test_sympy__functions__elementary__trigonometric__atan():
from sympy.functions.elementary.trigonometric import atan
assert _test_args(atan(2))
def test_sympy__functions__elementary__trigonometric__atan2():
from sympy.functions.elementary.trigonometric import atan2
assert _test_args(atan2(2, 3))
def test_sympy__functions__elementary__trigonometric__cos():
from sympy.functions.elementary.trigonometric import cos
assert _test_args(cos(2))
def test_sympy__functions__elementary__trigonometric__csc():
from sympy.functions.elementary.trigonometric import csc
assert _test_args(csc(2))
def test_sympy__functions__elementary__trigonometric__cot():
from sympy.functions.elementary.trigonometric import cot
assert _test_args(cot(2))
def test_sympy__functions__elementary__trigonometric__sin():
assert _test_args(sin(2))
def test_sympy__functions__elementary__trigonometric__sinc():
from sympy.functions.elementary.trigonometric import sinc
assert _test_args(sinc(2))
def test_sympy__functions__elementary__trigonometric__sec():
from sympy.functions.elementary.trigonometric import sec
assert _test_args(sec(2))
def test_sympy__functions__elementary__trigonometric__tan():
from sympy.functions.elementary.trigonometric import tan
assert _test_args(tan(2))
@SKIP("abstract class")
def test_sympy__functions__special__bessel__BesselBase():
pass
@SKIP("abstract class")
def test_sympy__functions__special__bessel__SphericalBesselBase():
pass
@SKIP("abstract class")
def test_sympy__functions__special__bessel__SphericalHankelBase():
pass
def test_sympy__functions__special__bessel__besseli():
from sympy.functions.special.bessel import besseli
assert _test_args(besseli(x, 1))
def test_sympy__functions__special__bessel__besselj():
from sympy.functions.special.bessel import besselj
assert _test_args(besselj(x, 1))
def test_sympy__functions__special__bessel__besselk():
from sympy.functions.special.bessel import besselk
assert _test_args(besselk(x, 1))
def test_sympy__functions__special__bessel__bessely():
from sympy.functions.special.bessel import bessely
assert _test_args(bessely(x, 1))
def test_sympy__functions__special__bessel__hankel1():
from sympy.functions.special.bessel import hankel1
assert _test_args(hankel1(x, 1))
def test_sympy__functions__special__bessel__hankel2():
from sympy.functions.special.bessel import hankel2
assert _test_args(hankel2(x, 1))
def test_sympy__functions__special__bessel__jn():
from sympy.functions.special.bessel import jn
assert _test_args(jn(0, x))
def test_sympy__functions__special__bessel__yn():
from sympy.functions.special.bessel import yn
assert _test_args(yn(0, x))
def test_sympy__functions__special__bessel__hn1():
from sympy.functions.special.bessel import hn1
assert _test_args(hn1(0, x))
def test_sympy__functions__special__bessel__hn2():
from sympy.functions.special.bessel import hn2
assert _test_args(hn2(0, x))
def test_sympy__functions__special__bessel__AiryBase():
pass
def test_sympy__functions__special__bessel__airyai():
from sympy.functions.special.bessel import airyai
assert _test_args(airyai(2))
def test_sympy__functions__special__bessel__airybi():
from sympy.functions.special.bessel import airybi
assert _test_args(airybi(2))
def test_sympy__functions__special__bessel__airyaiprime():
from sympy.functions.special.bessel import airyaiprime
assert _test_args(airyaiprime(2))
def test_sympy__functions__special__bessel__airybiprime():
from sympy.functions.special.bessel import airybiprime
assert _test_args(airybiprime(2))
def test_sympy__functions__special__elliptic_integrals__elliptic_k():
from sympy.functions.special.elliptic_integrals import elliptic_k as K
assert _test_args(K(x))
def test_sympy__functions__special__elliptic_integrals__elliptic_f():
from sympy.functions.special.elliptic_integrals import elliptic_f as F
assert _test_args(F(x, y))
def test_sympy__functions__special__elliptic_integrals__elliptic_e():
from sympy.functions.special.elliptic_integrals import elliptic_e as E
assert _test_args(E(x))
assert _test_args(E(x, y))
def test_sympy__functions__special__elliptic_integrals__elliptic_pi():
from sympy.functions.special.elliptic_integrals import elliptic_pi as P
assert _test_args(P(x, y))
assert _test_args(P(x, y, z))
def test_sympy__functions__special__delta_functions__DiracDelta():
from sympy.functions.special.delta_functions import DiracDelta
assert _test_args(DiracDelta(x, 1))
def test_sympy__functions__special__singularity_functions__SingularityFunction():
from sympy.functions.special.singularity_functions import SingularityFunction
assert _test_args(SingularityFunction(x, y, z))
def test_sympy__functions__special__delta_functions__Heaviside():
from sympy.functions.special.delta_functions import Heaviside
assert _test_args(Heaviside(x))
def test_sympy__functions__special__error_functions__erf():
from sympy.functions.special.error_functions import erf
assert _test_args(erf(2))
def test_sympy__functions__special__error_functions__erfc():
from sympy.functions.special.error_functions import erfc
assert _test_args(erfc(2))
def test_sympy__functions__special__error_functions__erfi():
from sympy.functions.special.error_functions import erfi
assert _test_args(erfi(2))
def test_sympy__functions__special__error_functions__erf2():
from sympy.functions.special.error_functions import erf2
assert _test_args(erf2(2, 3))
def test_sympy__functions__special__error_functions__erfinv():
from sympy.functions.special.error_functions import erfinv
assert _test_args(erfinv(2))
def test_sympy__functions__special__error_functions__erfcinv():
from sympy.functions.special.error_functions import erfcinv
assert _test_args(erfcinv(2))
def test_sympy__functions__special__error_functions__erf2inv():
from sympy.functions.special.error_functions import erf2inv
assert _test_args(erf2inv(2, 3))
@SKIP("abstract class")
def test_sympy__functions__special__error_functions__FresnelIntegral():
pass
def test_sympy__functions__special__error_functions__fresnels():
from sympy.functions.special.error_functions import fresnels
assert _test_args(fresnels(2))
def test_sympy__functions__special__error_functions__fresnelc():
from sympy.functions.special.error_functions import fresnelc
assert _test_args(fresnelc(2))
def test_sympy__functions__special__error_functions__erfs():
from sympy.functions.special.error_functions import _erfs
assert _test_args(_erfs(2))
def test_sympy__functions__special__error_functions__Ei():
from sympy.functions.special.error_functions import Ei
assert _test_args(Ei(2))
def test_sympy__functions__special__error_functions__li():
from sympy.functions.special.error_functions import li
assert _test_args(li(2))
def test_sympy__functions__special__error_functions__Li():
from sympy.functions.special.error_functions import Li
assert _test_args(Li(2))
@SKIP("abstract class")
def test_sympy__functions__special__error_functions__TrigonometricIntegral():
pass
def test_sympy__functions__special__error_functions__Si():
from sympy.functions.special.error_functions import Si
assert _test_args(Si(2))
def test_sympy__functions__special__error_functions__Ci():
from sympy.functions.special.error_functions import Ci
assert _test_args(Ci(2))
def test_sympy__functions__special__error_functions__Shi():
from sympy.functions.special.error_functions import Shi
assert _test_args(Shi(2))
def test_sympy__functions__special__error_functions__Chi():
from sympy.functions.special.error_functions import Chi
assert _test_args(Chi(2))
def test_sympy__functions__special__error_functions__expint():
from sympy.functions.special.error_functions import expint
assert _test_args(expint(y, x))
def test_sympy__functions__special__gamma_functions__gamma():
from sympy.functions.special.gamma_functions import gamma
assert _test_args(gamma(x))
def test_sympy__functions__special__gamma_functions__loggamma():
from sympy.functions.special.gamma_functions import loggamma
assert _test_args(loggamma(2))
def test_sympy__functions__special__gamma_functions__lowergamma():
from sympy.functions.special.gamma_functions import lowergamma
assert _test_args(lowergamma(x, 2))
def test_sympy__functions__special__gamma_functions__polygamma():
from sympy.functions.special.gamma_functions import polygamma
assert _test_args(polygamma(x, 2))
def test_sympy__functions__special__gamma_functions__uppergamma():
from sympy.functions.special.gamma_functions import uppergamma
assert _test_args(uppergamma(x, 2))
def test_sympy__functions__special__beta_functions__beta():
from sympy.functions.special.beta_functions import beta
assert _test_args(beta(x, x))
def test_sympy__functions__special__mathieu_functions__MathieuBase():
pass
def test_sympy__functions__special__mathieu_functions__mathieus():
from sympy.functions.special.mathieu_functions import mathieus
assert _test_args(mathieus(1, 1, 1))
def test_sympy__functions__special__mathieu_functions__mathieuc():
from sympy.functions.special.mathieu_functions import mathieuc
assert _test_args(mathieuc(1, 1, 1))
def test_sympy__functions__special__mathieu_functions__mathieusprime():
from sympy.functions.special.mathieu_functions import mathieusprime
assert _test_args(mathieusprime(1, 1, 1))
def test_sympy__functions__special__mathieu_functions__mathieucprime():
from sympy.functions.special.mathieu_functions import mathieucprime
assert _test_args(mathieucprime(1, 1, 1))
@SKIP("abstract class")
def test_sympy__functions__special__hyper__TupleParametersBase():
pass
@SKIP("abstract class")
def test_sympy__functions__special__hyper__TupleArg():
pass
def test_sympy__functions__special__hyper__hyper():
from sympy.functions.special.hyper import hyper
assert _test_args(hyper([1, 2, 3], [4, 5], x))
def test_sympy__functions__special__hyper__meijerg():
from sympy.functions.special.hyper import meijerg
assert _test_args(meijerg([1, 2, 3], [4, 5], [6], [], x))
@SKIP("abstract class")
def test_sympy__functions__special__hyper__HyperRep():
pass
def test_sympy__functions__special__hyper__HyperRep_power1():
from sympy.functions.special.hyper import HyperRep_power1
assert _test_args(HyperRep_power1(x, y))
def test_sympy__functions__special__hyper__HyperRep_power2():
from sympy.functions.special.hyper import HyperRep_power2
assert _test_args(HyperRep_power2(x, y))
def test_sympy__functions__special__hyper__HyperRep_log1():
from sympy.functions.special.hyper import HyperRep_log1
assert _test_args(HyperRep_log1(x))
def test_sympy__functions__special__hyper__HyperRep_atanh():
from sympy.functions.special.hyper import HyperRep_atanh
assert _test_args(HyperRep_atanh(x))
def test_sympy__functions__special__hyper__HyperRep_asin1():
from sympy.functions.special.hyper import HyperRep_asin1
assert _test_args(HyperRep_asin1(x))
def test_sympy__functions__special__hyper__HyperRep_asin2():
from sympy.functions.special.hyper import HyperRep_asin2
assert _test_args(HyperRep_asin2(x))
def test_sympy__functions__special__hyper__HyperRep_sqrts1():
from sympy.functions.special.hyper import HyperRep_sqrts1
assert _test_args(HyperRep_sqrts1(x, y))
def test_sympy__functions__special__hyper__HyperRep_sqrts2():
from sympy.functions.special.hyper import HyperRep_sqrts2
assert _test_args(HyperRep_sqrts2(x, y))
def test_sympy__functions__special__hyper__HyperRep_log2():
from sympy.functions.special.hyper import HyperRep_log2
assert _test_args(HyperRep_log2(x))
def test_sympy__functions__special__hyper__HyperRep_cosasin():
from sympy.functions.special.hyper import HyperRep_cosasin
assert _test_args(HyperRep_cosasin(x, y))
def test_sympy__functions__special__hyper__HyperRep_sinasin():
from sympy.functions.special.hyper import HyperRep_sinasin
assert _test_args(HyperRep_sinasin(x, y))
def test_sympy__functions__special__hyper__appellf1():
from sympy.functions.special.hyper import appellf1
a, b1, b2, c, x, y = symbols('a b1 b2 c x y')
assert _test_args(appellf1(a, b1, b2, c, x, y))
@SKIP("abstract class")
def test_sympy__functions__special__polynomials__OrthogonalPolynomial():
pass
def test_sympy__functions__special__polynomials__jacobi():
from sympy.functions.special.polynomials import jacobi
assert _test_args(jacobi(x, 2, 2, 2))
def test_sympy__functions__special__polynomials__gegenbauer():
from sympy.functions.special.polynomials import gegenbauer
assert _test_args(gegenbauer(x, 2, 2))
def test_sympy__functions__special__polynomials__chebyshevt():
from sympy.functions.special.polynomials import chebyshevt
assert _test_args(chebyshevt(x, 2))
def test_sympy__functions__special__polynomials__chebyshevt_root():
from sympy.functions.special.polynomials import chebyshevt_root
assert _test_args(chebyshevt_root(3, 2))
def test_sympy__functions__special__polynomials__chebyshevu():
from sympy.functions.special.polynomials import chebyshevu
assert _test_args(chebyshevu(x, 2))
def test_sympy__functions__special__polynomials__chebyshevu_root():
from sympy.functions.special.polynomials import chebyshevu_root
assert _test_args(chebyshevu_root(3, 2))
def test_sympy__functions__special__polynomials__hermite():
from sympy.functions.special.polynomials import hermite
assert _test_args(hermite(x, 2))
def test_sympy__functions__special__polynomials__legendre():
from sympy.functions.special.polynomials import legendre
assert _test_args(legendre(x, 2))
def test_sympy__functions__special__polynomials__assoc_legendre():
from sympy.functions.special.polynomials import assoc_legendre
assert _test_args(assoc_legendre(x, 0, y))
def test_sympy__functions__special__polynomials__laguerre():
from sympy.functions.special.polynomials import laguerre
assert _test_args(laguerre(x, 2))
def test_sympy__functions__special__polynomials__assoc_laguerre():
from sympy.functions.special.polynomials import assoc_laguerre
assert _test_args(assoc_laguerre(x, 0, y))
def test_sympy__functions__special__spherical_harmonics__Ynm():
from sympy.functions.special.spherical_harmonics import Ynm
assert _test_args(Ynm(1, 1, x, y))
def test_sympy__functions__special__spherical_harmonics__Znm():
from sympy.functions.special.spherical_harmonics import Znm
assert _test_args(Znm(1, 1, x, y))
def test_sympy__functions__special__tensor_functions__LeviCivita():
from sympy.functions.special.tensor_functions import LeviCivita
assert _test_args(LeviCivita(x, y, 2))
def test_sympy__functions__special__tensor_functions__KroneckerDelta():
from sympy.functions.special.tensor_functions import KroneckerDelta
assert _test_args(KroneckerDelta(x, y))
def test_sympy__functions__special__zeta_functions__dirichlet_eta():
from sympy.functions.special.zeta_functions import dirichlet_eta
assert _test_args(dirichlet_eta(x))
def test_sympy__functions__special__zeta_functions__zeta():
from sympy.functions.special.zeta_functions import zeta
assert _test_args(zeta(101))
def test_sympy__functions__special__zeta_functions__lerchphi():
from sympy.functions.special.zeta_functions import lerchphi
assert _test_args(lerchphi(x, y, z))
def test_sympy__functions__special__zeta_functions__polylog():
from sympy.functions.special.zeta_functions import polylog
assert _test_args(polylog(x, y))
def test_sympy__functions__special__zeta_functions__stieltjes():
from sympy.functions.special.zeta_functions import stieltjes
assert _test_args(stieltjes(x, y))
def test_sympy__integrals__integrals__Integral():
from sympy.integrals.integrals import Integral
assert _test_args(Integral(2, (x, 0, 1)))
def test_sympy__integrals__risch__NonElementaryIntegral():
from sympy.integrals.risch import NonElementaryIntegral
assert _test_args(NonElementaryIntegral(exp(-x**2), x))
@SKIP("abstract class")
def test_sympy__integrals__transforms__IntegralTransform():
pass
def test_sympy__integrals__transforms__MellinTransform():
from sympy.integrals.transforms import MellinTransform
assert _test_args(MellinTransform(2, x, y))
def test_sympy__integrals__transforms__InverseMellinTransform():
from sympy.integrals.transforms import InverseMellinTransform
assert _test_args(InverseMellinTransform(2, x, y, 0, 1))
def test_sympy__integrals__transforms__LaplaceTransform():
from sympy.integrals.transforms import LaplaceTransform
assert _test_args(LaplaceTransform(2, x, y))
def test_sympy__integrals__transforms__InverseLaplaceTransform():
from sympy.integrals.transforms import InverseLaplaceTransform
assert _test_args(InverseLaplaceTransform(2, x, y, 0))
@SKIP("abstract class")
def test_sympy__integrals__transforms__FourierTypeTransform():
pass
def test_sympy__integrals__transforms__InverseFourierTransform():
from sympy.integrals.transforms import InverseFourierTransform
assert _test_args(InverseFourierTransform(2, x, y))
def test_sympy__integrals__transforms__FourierTransform():
from sympy.integrals.transforms import FourierTransform
assert _test_args(FourierTransform(2, x, y))
@SKIP("abstract class")
def test_sympy__integrals__transforms__SineCosineTypeTransform():
pass
def test_sympy__integrals__transforms__InverseSineTransform():
from sympy.integrals.transforms import InverseSineTransform
assert _test_args(InverseSineTransform(2, x, y))
def test_sympy__integrals__transforms__SineTransform():
from sympy.integrals.transforms import SineTransform
assert _test_args(SineTransform(2, x, y))
def test_sympy__integrals__transforms__InverseCosineTransform():
from sympy.integrals.transforms import InverseCosineTransform
assert _test_args(InverseCosineTransform(2, x, y))
def test_sympy__integrals__transforms__CosineTransform():
from sympy.integrals.transforms import CosineTransform
assert _test_args(CosineTransform(2, x, y))
@SKIP("abstract class")
def test_sympy__integrals__transforms__HankelTypeTransform():
pass
def test_sympy__integrals__transforms__InverseHankelTransform():
from sympy.integrals.transforms import InverseHankelTransform
assert _test_args(InverseHankelTransform(2, x, y, 0))
def test_sympy__integrals__transforms__HankelTransform():
from sympy.integrals.transforms import HankelTransform
assert _test_args(HankelTransform(2, x, y, 0))
@XFAIL
def test_sympy__liealgebras__cartan_type__CartanType_generator():
from sympy.liealgebras.cartan_type import CartanType_generator
assert _test_args(CartanType_generator("A2"))
@XFAIL
def test_sympy__liealgebras__cartan_type__Standard_Cartan():
from sympy.liealgebras.cartan_type import Standard_Cartan
assert _test_args(Standard_Cartan("A", 2))
@XFAIL
def test_sympy__liealgebras__weyl_group__WeylGroup():
from sympy.liealgebras.weyl_group import WeylGroup
assert _test_args(WeylGroup("B4"))
@XFAIL
def test_sympy__liealgebras__root_system__RootSystem():
from sympy.liealgebras.root_system import RootSystem
assert _test_args(RootSystem("A2"))
@XFAIL
def test_sympy__liealgebras__type_a__TypeA():
from sympy.liealgebras.type_a import TypeA
assert _test_args(TypeA(2))
@XFAIL
def test_sympy__liealgebras__type_b__TypeB():
from sympy.liealgebras.type_b import TypeB
assert _test_args(TypeB(4))
@XFAIL
def test_sympy__liealgebras__type_c__TypeC():
from sympy.liealgebras.type_c import TypeC
assert _test_args(TypeC(4))
@XFAIL
def test_sympy__liealgebras__type_d__TypeD():
from sympy.liealgebras.type_d import TypeD
assert _test_args(TypeD(4))
@XFAIL
def test_sympy__liealgebras__type_e__TypeE():
from sympy.liealgebras.type_e import TypeE
assert _test_args(TypeE(6))
@XFAIL
def test_sympy__liealgebras__type_f__TypeF():
from sympy.liealgebras.type_f import TypeF
assert _test_args(TypeF(4))
@XFAIL
def test_sympy__liealgebras__type_g__TypeG():
from sympy.liealgebras.type_g import TypeG
assert _test_args(TypeG(2))
def test_sympy__logic__boolalg__And():
from sympy.logic.boolalg import And
assert _test_args(And(x, y, 1))
@SKIP("abstract class")
def test_sympy__logic__boolalg__Boolean():
pass
def test_sympy__logic__boolalg__BooleanFunction():
from sympy.logic.boolalg import BooleanFunction
assert _test_args(BooleanFunction(1, 2, 3))
@SKIP("abstract class")
def test_sympy__logic__boolalg__BooleanAtom():
pass
def test_sympy__logic__boolalg__BooleanTrue():
from sympy.logic.boolalg import true
assert _test_args(true)
def test_sympy__logic__boolalg__BooleanFalse():
from sympy.logic.boolalg import false
assert _test_args(false)
def test_sympy__logic__boolalg__Equivalent():
from sympy.logic.boolalg import Equivalent
assert _test_args(Equivalent(x, 2))
def test_sympy__logic__boolalg__ITE():
from sympy.logic.boolalg import ITE
assert _test_args(ITE(x, y, 1))
def test_sympy__logic__boolalg__Implies():
from sympy.logic.boolalg import Implies
assert _test_args(Implies(x, y))
def test_sympy__logic__boolalg__Nand():
from sympy.logic.boolalg import Nand
assert _test_args(Nand(x, y, 1))
def test_sympy__logic__boolalg__Nor():
from sympy.logic.boolalg import Nor
assert _test_args(Nor(x, y))
def test_sympy__logic__boolalg__Not():
from sympy.logic.boolalg import Not
assert _test_args(Not(x))
def test_sympy__logic__boolalg__Or():
from sympy.logic.boolalg import Or
assert _test_args(Or(x, y))
def test_sympy__logic__boolalg__Xor():
from sympy.logic.boolalg import Xor
assert _test_args(Xor(x, y, 2))
def test_sympy__logic__boolalg__Xnor():
from sympy.logic.boolalg import Xnor
assert _test_args(Xnor(x, y, 2))
def test_sympy__matrices__matrices__DeferredVector():
from sympy.matrices.matrices import DeferredVector
assert _test_args(DeferredVector("X"))
@SKIP("abstract class")
def test_sympy__matrices__expressions__matexpr__MatrixBase():
pass
def test_sympy__matrices__immutable__ImmutableDenseMatrix():
from sympy.matrices.immutable import ImmutableDenseMatrix
m = ImmutableDenseMatrix([[1, 2], [3, 4]])
assert _test_args(m)
assert _test_args(Basic(*list(m)))
m = ImmutableDenseMatrix(1, 1, [1])
assert _test_args(m)
assert _test_args(Basic(*list(m)))
m = ImmutableDenseMatrix(2, 2, lambda i, j: 1)
assert m[0, 0] is S.One
m = ImmutableDenseMatrix(2, 2, lambda i, j: 1/(1 + i) + 1/(1 + j))
assert m[1, 1] is S.One # true div. will give 1.0 if i,j not sympified
assert _test_args(m)
assert _test_args(Basic(*list(m)))
def test_sympy__matrices__immutable__ImmutableSparseMatrix():
from sympy.matrices.immutable import ImmutableSparseMatrix
m = ImmutableSparseMatrix([[1, 2], [3, 4]])
assert _test_args(m)
assert _test_args(Basic(*list(m)))
m = ImmutableSparseMatrix(1, 1, {(0, 0): 1})
assert _test_args(m)
assert _test_args(Basic(*list(m)))
m = ImmutableSparseMatrix(1, 1, [1])
assert _test_args(m)
assert _test_args(Basic(*list(m)))
m = ImmutableSparseMatrix(2, 2, lambda i, j: 1)
assert m[0, 0] is S.One
m = ImmutableSparseMatrix(2, 2, lambda i, j: 1/(1 + i) + 1/(1 + j))
assert m[1, 1] is S.One # true div. will give 1.0 if i,j not sympified
assert _test_args(m)
assert _test_args(Basic(*list(m)))
def test_sympy__matrices__expressions__slice__MatrixSlice():
from sympy.matrices.expressions.slice import MatrixSlice
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', 4, 4)
assert _test_args(MatrixSlice(X, (0, 2), (0, 2)))
def test_sympy__matrices__expressions__applyfunc__ElementwiseApplyFunction():
from sympy.matrices.expressions.applyfunc import ElementwiseApplyFunction
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol("X", x, x)
func = Lambda(x, x**2)
assert _test_args(ElementwiseApplyFunction(func, X))
def test_sympy__matrices__expressions__blockmatrix__BlockDiagMatrix():
from sympy.matrices.expressions.blockmatrix import BlockDiagMatrix
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, x)
Y = MatrixSymbol('Y', y, y)
assert _test_args(BlockDiagMatrix(X, Y))
def test_sympy__matrices__expressions__blockmatrix__BlockMatrix():
from sympy.matrices.expressions.blockmatrix import BlockMatrix
from sympy.matrices.expressions import MatrixSymbol, ZeroMatrix
X = MatrixSymbol('X', x, x)
Y = MatrixSymbol('Y', y, y)
Z = MatrixSymbol('Z', x, y)
O = ZeroMatrix(y, x)
assert _test_args(BlockMatrix([[X, Z], [O, Y]]))
def test_sympy__matrices__expressions__inverse__Inverse():
from sympy.matrices.expressions.inverse import Inverse
from sympy.matrices.expressions import MatrixSymbol
assert _test_args(Inverse(MatrixSymbol('A', 3, 3)))
def test_sympy__matrices__expressions__matadd__MatAdd():
from sympy.matrices.expressions.matadd import MatAdd
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, y)
Y = MatrixSymbol('Y', x, y)
assert _test_args(MatAdd(X, Y))
def test_sympy__matrices__expressions__matexpr__Identity():
from sympy.matrices.expressions.matexpr import Identity
assert _test_args(Identity(3))
@SKIP("abstract class")
def test_sympy__matrices__expressions__matexpr__MatrixExpr():
pass
def test_sympy__matrices__expressions__matexpr__MatrixElement():
from sympy.matrices.expressions.matexpr import MatrixSymbol, MatrixElement
from sympy import S
assert _test_args(MatrixElement(MatrixSymbol('A', 3, 5), S(2), S(3)))
@XFAIL
def test_sympy__matrices__expressions__matexpr__MatrixSymbol():
from sympy.matrices.expressions.matexpr import MatrixSymbol
assert _test_args(MatrixSymbol('A', 3, 5))
def test_sympy__matrices__expressions__matexpr__ZeroMatrix():
from sympy.matrices.expressions.matexpr import ZeroMatrix
assert _test_args(ZeroMatrix(3, 5))
def test_sympy__matrices__expressions__matmul__MatMul():
from sympy.matrices.expressions.matmul import MatMul
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, y)
Y = MatrixSymbol('Y', y, x)
assert _test_args(MatMul(X, Y))
def test_sympy__matrices__expressions__dotproduct__DotProduct():
from sympy.matrices.expressions.dotproduct import DotProduct
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, 1)
Y = MatrixSymbol('Y', x, 1)
assert _test_args(DotProduct(X, Y))
def test_sympy__matrices__expressions__diagonal__DiagonalMatrix():
from sympy.matrices.expressions.diagonal import DiagonalMatrix
from sympy.matrices.expressions import MatrixSymbol
x = MatrixSymbol('x', 10, 1)
assert _test_args(DiagonalMatrix(x))
def test_sympy__matrices__expressions__diagonal__DiagonalOf():
from sympy.matrices.expressions.diagonal import DiagonalOf
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('x', 10, 10)
assert _test_args(DiagonalOf(X))
def test_sympy__matrices__expressions__hadamard__HadamardProduct():
from sympy.matrices.expressions.hadamard import HadamardProduct
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, y)
Y = MatrixSymbol('Y', x, y)
assert _test_args(HadamardProduct(X, Y))
def test_sympy__matrices__expressions__kronecker__KroneckerProduct():
from sympy.matrices.expressions.kronecker import KroneckerProduct
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, y)
Y = MatrixSymbol('Y', x, y)
assert _test_args(KroneckerProduct(X, Y))
def test_sympy__matrices__expressions__matpow__MatPow():
from sympy.matrices.expressions.matpow import MatPow
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', x, x)
assert _test_args(MatPow(X, 2))
def test_sympy__matrices__expressions__transpose__Transpose():
from sympy.matrices.expressions.transpose import Transpose
from sympy.matrices.expressions import MatrixSymbol
assert _test_args(Transpose(MatrixSymbol('A', 3, 5)))
def test_sympy__matrices__expressions__adjoint__Adjoint():
from sympy.matrices.expressions.adjoint import Adjoint
from sympy.matrices.expressions import MatrixSymbol
assert _test_args(Adjoint(MatrixSymbol('A', 3, 5)))
def test_sympy__matrices__expressions__trace__Trace():
from sympy.matrices.expressions.trace import Trace
from sympy.matrices.expressions import MatrixSymbol
assert _test_args(Trace(MatrixSymbol('A', 3, 3)))
def test_sympy__matrices__expressions__determinant__Determinant():
from sympy.matrices.expressions.determinant import Determinant
from sympy.matrices.expressions import MatrixSymbol
assert _test_args(Determinant(MatrixSymbol('A', 3, 3)))
def test_sympy__matrices__expressions__funcmatrix__FunctionMatrix():
from sympy.matrices.expressions.funcmatrix import FunctionMatrix
from sympy import symbols
i, j = symbols('i,j')
assert _test_args(FunctionMatrix(3, 3, Lambda((i, j), i - j) ))
def test_sympy__matrices__expressions__fourier__DFT():
from sympy.matrices.expressions.fourier import DFT
from sympy import S
assert _test_args(DFT(S(2)))
def test_sympy__matrices__expressions__fourier__IDFT():
from sympy.matrices.expressions.fourier import IDFT
from sympy import S
assert _test_args(IDFT(S(2)))
from sympy.matrices.expressions import MatrixSymbol
X = MatrixSymbol('X', 10, 10)
def test_sympy__matrices__expressions__factorizations__LofLU():
from sympy.matrices.expressions.factorizations import LofLU
assert _test_args(LofLU(X))
def test_sympy__matrices__expressions__factorizations__UofLU():
from sympy.matrices.expressions.factorizations import UofLU
assert _test_args(UofLU(X))
def test_sympy__matrices__expressions__factorizations__QofQR():
from sympy.matrices.expressions.factorizations import QofQR
assert _test_args(QofQR(X))
def test_sympy__matrices__expressions__factorizations__RofQR():
from sympy.matrices.expressions.factorizations import RofQR
assert _test_args(RofQR(X))
def test_sympy__matrices__expressions__factorizations__LofCholesky():
from sympy.matrices.expressions.factorizations import LofCholesky
assert _test_args(LofCholesky(X))
def test_sympy__matrices__expressions__factorizations__UofCholesky():
from sympy.matrices.expressions.factorizations import UofCholesky
assert _test_args(UofCholesky(X))
def test_sympy__matrices__expressions__factorizations__EigenVectors():
from sympy.matrices.expressions.factorizations import EigenVectors
assert _test_args(EigenVectors(X))
def test_sympy__matrices__expressions__factorizations__EigenValues():
from sympy.matrices.expressions.factorizations import EigenValues
assert _test_args(EigenValues(X))
def test_sympy__matrices__expressions__factorizations__UofSVD():
from sympy.matrices.expressions.factorizations import UofSVD
assert _test_args(UofSVD(X))
def test_sympy__matrices__expressions__factorizations__VofSVD():
from sympy.matrices.expressions.factorizations import VofSVD
assert _test_args(VofSVD(X))
def test_sympy__matrices__expressions__factorizations__SofSVD():
from sympy.matrices.expressions.factorizations import SofSVD
assert _test_args(SofSVD(X))
@SKIP("abstract class")
def test_sympy__matrices__expressions__factorizations__Factorization():
pass
def test_sympy__physics__vector__frame__CoordinateSym():
from sympy.physics.vector import CoordinateSym
from sympy.physics.vector import ReferenceFrame
assert _test_args(CoordinateSym('R_x', ReferenceFrame('R'), 0))
def test_sympy__physics__paulialgebra__Pauli():
from sympy.physics.paulialgebra import Pauli
assert _test_args(Pauli(1))
def test_sympy__physics__quantum__anticommutator__AntiCommutator():
from sympy.physics.quantum.anticommutator import AntiCommutator
assert _test_args(AntiCommutator(x, y))
def test_sympy__physics__quantum__cartesian__PositionBra3D():
from sympy.physics.quantum.cartesian import PositionBra3D
assert _test_args(PositionBra3D(x, y, z))
def test_sympy__physics__quantum__cartesian__PositionKet3D():
from sympy.physics.quantum.cartesian import PositionKet3D
assert _test_args(PositionKet3D(x, y, z))
def test_sympy__physics__quantum__cartesian__PositionState3D():
from sympy.physics.quantum.cartesian import PositionState3D
assert _test_args(PositionState3D(x, y, z))
def test_sympy__physics__quantum__cartesian__PxBra():
from sympy.physics.quantum.cartesian import PxBra
assert _test_args(PxBra(x, y, z))
def test_sympy__physics__quantum__cartesian__PxKet():
from sympy.physics.quantum.cartesian import PxKet
assert _test_args(PxKet(x, y, z))
def test_sympy__physics__quantum__cartesian__PxOp():
from sympy.physics.quantum.cartesian import PxOp
assert _test_args(PxOp(x, y, z))
def test_sympy__physics__quantum__cartesian__XBra():
from sympy.physics.quantum.cartesian import XBra
assert _test_args(XBra(x))
def test_sympy__physics__quantum__cartesian__XKet():
from sympy.physics.quantum.cartesian import XKet
assert _test_args(XKet(x))
def test_sympy__physics__quantum__cartesian__XOp():
from sympy.physics.quantum.cartesian import XOp
assert _test_args(XOp(x))
def test_sympy__physics__quantum__cartesian__YOp():
from sympy.physics.quantum.cartesian import YOp
assert _test_args(YOp(x))
def test_sympy__physics__quantum__cartesian__ZOp():
from sympy.physics.quantum.cartesian import ZOp
assert _test_args(ZOp(x))
def test_sympy__physics__quantum__cg__CG():
from sympy.physics.quantum.cg import CG
from sympy import S
assert _test_args(CG(S(3)/2, S(3)/2, S(1)/2, -S(1)/2, 1, 1))
def test_sympy__physics__quantum__cg__Wigner3j():
from sympy.physics.quantum.cg import Wigner3j
assert _test_args(Wigner3j(6, 0, 4, 0, 2, 0))
def test_sympy__physics__quantum__cg__Wigner6j():
from sympy.physics.quantum.cg import Wigner6j
assert _test_args(Wigner6j(1, 2, 3, 2, 1, 2))
def test_sympy__physics__quantum__cg__Wigner9j():
from sympy.physics.quantum.cg import Wigner9j
assert _test_args(Wigner9j(2, 1, 1, S(3)/2, S(1)/2, 1, S(1)/2, S(1)/2, 0))
def test_sympy__physics__quantum__circuitplot__Mz():
from sympy.physics.quantum.circuitplot import Mz
assert _test_args(Mz(0))
def test_sympy__physics__quantum__circuitplot__Mx():
from sympy.physics.quantum.circuitplot import Mx
assert _test_args(Mx(0))
def test_sympy__physics__quantum__commutator__Commutator():
from sympy.physics.quantum.commutator import Commutator
A, B = symbols('A,B', commutative=False)
assert _test_args(Commutator(A, B))
def test_sympy__physics__quantum__constants__HBar():
from sympy.physics.quantum.constants import HBar
assert _test_args(HBar())
def test_sympy__physics__quantum__dagger__Dagger():
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.state import Ket
assert _test_args(Dagger(Dagger(Ket('psi'))))
def test_sympy__physics__quantum__gate__CGate():
from sympy.physics.quantum.gate import CGate, Gate
assert _test_args(CGate((0, 1), Gate(2)))
def test_sympy__physics__quantum__gate__CGateS():
from sympy.physics.quantum.gate import CGateS, Gate
assert _test_args(CGateS((0, 1), Gate(2)))
def test_sympy__physics__quantum__gate__CNotGate():
from sympy.physics.quantum.gate import CNotGate
assert _test_args(CNotGate(0, 1))
def test_sympy__physics__quantum__gate__Gate():
from sympy.physics.quantum.gate import Gate
assert _test_args(Gate(0))
def test_sympy__physics__quantum__gate__HadamardGate():
from sympy.physics.quantum.gate import HadamardGate
assert _test_args(HadamardGate(0))
def test_sympy__physics__quantum__gate__IdentityGate():
from sympy.physics.quantum.gate import IdentityGate
assert _test_args(IdentityGate(0))
def test_sympy__physics__quantum__gate__OneQubitGate():
from sympy.physics.quantum.gate import OneQubitGate
assert _test_args(OneQubitGate(0))
def test_sympy__physics__quantum__gate__PhaseGate():
from sympy.physics.quantum.gate import PhaseGate
assert _test_args(PhaseGate(0))
def test_sympy__physics__quantum__gate__SwapGate():
from sympy.physics.quantum.gate import SwapGate
assert _test_args(SwapGate(0, 1))
def test_sympy__physics__quantum__gate__TGate():
from sympy.physics.quantum.gate import TGate
assert _test_args(TGate(0))
def test_sympy__physics__quantum__gate__TwoQubitGate():
from sympy.physics.quantum.gate import TwoQubitGate
assert _test_args(TwoQubitGate(0))
def test_sympy__physics__quantum__gate__UGate():
from sympy.physics.quantum.gate import UGate
from sympy.matrices.immutable import ImmutableDenseMatrix
from sympy import Integer, Tuple
assert _test_args(
UGate(Tuple(Integer(1)), ImmutableDenseMatrix([[1, 0], [0, 2]])))
def test_sympy__physics__quantum__gate__XGate():
from sympy.physics.quantum.gate import XGate
assert _test_args(XGate(0))
def test_sympy__physics__quantum__gate__YGate():
from sympy.physics.quantum.gate import YGate
assert _test_args(YGate(0))
def test_sympy__physics__quantum__gate__ZGate():
from sympy.physics.quantum.gate import ZGate
assert _test_args(ZGate(0))
@SKIP("TODO: sympy.physics")
def test_sympy__physics__quantum__grover__OracleGate():
from sympy.physics.quantum.grover import OracleGate
assert _test_args(OracleGate())
def test_sympy__physics__quantum__grover__WGate():
from sympy.physics.quantum.grover import WGate
assert _test_args(WGate(1))
def test_sympy__physics__quantum__hilbert__ComplexSpace():
from sympy.physics.quantum.hilbert import ComplexSpace
assert _test_args(ComplexSpace(x))
def test_sympy__physics__quantum__hilbert__DirectSumHilbertSpace():
from sympy.physics.quantum.hilbert import DirectSumHilbertSpace, ComplexSpace, FockSpace
c = ComplexSpace(2)
f = FockSpace()
assert _test_args(DirectSumHilbertSpace(c, f))
def test_sympy__physics__quantum__hilbert__FockSpace():
from sympy.physics.quantum.hilbert import FockSpace
assert _test_args(FockSpace())
def test_sympy__physics__quantum__hilbert__HilbertSpace():
from sympy.physics.quantum.hilbert import HilbertSpace
assert _test_args(HilbertSpace())
def test_sympy__physics__quantum__hilbert__L2():
from sympy.physics.quantum.hilbert import L2
from sympy import oo, Interval
assert _test_args(L2(Interval(0, oo)))
def test_sympy__physics__quantum__hilbert__TensorPowerHilbertSpace():
from sympy.physics.quantum.hilbert import TensorPowerHilbertSpace, FockSpace
f = FockSpace()
assert _test_args(TensorPowerHilbertSpace(f, 2))
def test_sympy__physics__quantum__hilbert__TensorProductHilbertSpace():
from sympy.physics.quantum.hilbert import TensorProductHilbertSpace, FockSpace, ComplexSpace
c = ComplexSpace(2)
f = FockSpace()
assert _test_args(TensorProductHilbertSpace(f, c))
def test_sympy__physics__quantum__innerproduct__InnerProduct():
from sympy.physics.quantum import Bra, Ket, InnerProduct
b = Bra('b')
k = Ket('k')
assert _test_args(InnerProduct(b, k))
def test_sympy__physics__quantum__operator__DifferentialOperator():
from sympy.physics.quantum.operator import DifferentialOperator
from sympy import Derivative, Function
f = Function('f')
assert _test_args(DifferentialOperator(1/x*Derivative(f(x), x), f(x)))
def test_sympy__physics__quantum__operator__HermitianOperator():
from sympy.physics.quantum.operator import HermitianOperator
assert _test_args(HermitianOperator('H'))
def test_sympy__physics__quantum__operator__IdentityOperator():
from sympy.physics.quantum.operator import IdentityOperator
assert _test_args(IdentityOperator(5))
def test_sympy__physics__quantum__operator__Operator():
from sympy.physics.quantum.operator import Operator
assert _test_args(Operator('A'))
def test_sympy__physics__quantum__operator__OuterProduct():
from sympy.physics.quantum.operator import OuterProduct
from sympy.physics.quantum import Ket, Bra
b = Bra('b')
k = Ket('k')
assert _test_args(OuterProduct(k, b))
def test_sympy__physics__quantum__operator__UnitaryOperator():
from sympy.physics.quantum.operator import UnitaryOperator
assert _test_args(UnitaryOperator('U'))
def test_sympy__physics__quantum__piab__PIABBra():
from sympy.physics.quantum.piab import PIABBra
assert _test_args(PIABBra('B'))
def test_sympy__physics__quantum__boson__BosonOp():
from sympy.physics.quantum.boson import BosonOp
assert _test_args(BosonOp('a'))
assert _test_args(BosonOp('a', False))
def test_sympy__physics__quantum__boson__BosonFockKet():
from sympy.physics.quantum.boson import BosonFockKet
assert _test_args(BosonFockKet(1))
def test_sympy__physics__quantum__boson__BosonFockBra():
from sympy.physics.quantum.boson import BosonFockBra
assert _test_args(BosonFockBra(1))
def test_sympy__physics__quantum__boson__BosonCoherentKet():
from sympy.physics.quantum.boson import BosonCoherentKet
assert _test_args(BosonCoherentKet(1))
def test_sympy__physics__quantum__boson__BosonCoherentBra():
from sympy.physics.quantum.boson import BosonCoherentBra
assert _test_args(BosonCoherentBra(1))
def test_sympy__physics__quantum__fermion__FermionOp():
from sympy.physics.quantum.fermion import FermionOp
assert _test_args(FermionOp('c'))
assert _test_args(FermionOp('c', False))
def test_sympy__physics__quantum__fermion__FermionFockKet():
from sympy.physics.quantum.fermion import FermionFockKet
assert _test_args(FermionFockKet(1))
def test_sympy__physics__quantum__fermion__FermionFockBra():
from sympy.physics.quantum.fermion import FermionFockBra
assert _test_args(FermionFockBra(1))
def test_sympy__physics__quantum__pauli__SigmaOpBase():
from sympy.physics.quantum.pauli import SigmaOpBase
assert _test_args(SigmaOpBase())
def test_sympy__physics__quantum__pauli__SigmaX():
from sympy.physics.quantum.pauli import SigmaX
assert _test_args(SigmaX())
def test_sympy__physics__quantum__pauli__SigmaY():
from sympy.physics.quantum.pauli import SigmaY
assert _test_args(SigmaY())
def test_sympy__physics__quantum__pauli__SigmaZ():
from sympy.physics.quantum.pauli import SigmaZ
assert _test_args(SigmaZ())
def test_sympy__physics__quantum__pauli__SigmaMinus():
from sympy.physics.quantum.pauli import SigmaMinus
assert _test_args(SigmaMinus())
def test_sympy__physics__quantum__pauli__SigmaPlus():
from sympy.physics.quantum.pauli import SigmaPlus
assert _test_args(SigmaPlus())
def test_sympy__physics__quantum__pauli__SigmaZKet():
from sympy.physics.quantum.pauli import SigmaZKet
assert _test_args(SigmaZKet(0))
def test_sympy__physics__quantum__pauli__SigmaZBra():
from sympy.physics.quantum.pauli import SigmaZBra
assert _test_args(SigmaZBra(0))
def test_sympy__physics__quantum__piab__PIABHamiltonian():
from sympy.physics.quantum.piab import PIABHamiltonian
assert _test_args(PIABHamiltonian('P'))
def test_sympy__physics__quantum__piab__PIABKet():
from sympy.physics.quantum.piab import PIABKet
assert _test_args(PIABKet('K'))
def test_sympy__physics__quantum__qexpr__QExpr():
from sympy.physics.quantum.qexpr import QExpr
assert _test_args(QExpr(0))
def test_sympy__physics__quantum__qft__Fourier():
from sympy.physics.quantum.qft import Fourier
assert _test_args(Fourier(0, 1))
def test_sympy__physics__quantum__qft__IQFT():
from sympy.physics.quantum.qft import IQFT
assert _test_args(IQFT(0, 1))
def test_sympy__physics__quantum__qft__QFT():
from sympy.physics.quantum.qft import QFT
assert _test_args(QFT(0, 1))
def test_sympy__physics__quantum__qft__RkGate():
from sympy.physics.quantum.qft import RkGate
assert _test_args(RkGate(0, 1))
def test_sympy__physics__quantum__qubit__IntQubit():
from sympy.physics.quantum.qubit import IntQubit
assert _test_args(IntQubit(0))
def test_sympy__physics__quantum__qubit__IntQubitBra():
from sympy.physics.quantum.qubit import IntQubitBra
assert _test_args(IntQubitBra(0))
def test_sympy__physics__quantum__qubit__IntQubitState():
from sympy.physics.quantum.qubit import IntQubitState, QubitState
assert _test_args(IntQubitState(QubitState(0, 1)))
def test_sympy__physics__quantum__qubit__Qubit():
from sympy.physics.quantum.qubit import Qubit
assert _test_args(Qubit(0, 0, 0))
def test_sympy__physics__quantum__qubit__QubitBra():
from sympy.physics.quantum.qubit import QubitBra
assert _test_args(QubitBra('1', 0))
def test_sympy__physics__quantum__qubit__QubitState():
from sympy.physics.quantum.qubit import QubitState
assert _test_args(QubitState(0, 1))
def test_sympy__physics__quantum__density__Density():
from sympy.physics.quantum.density import Density
from sympy.physics.quantum.state import Ket
assert _test_args(Density([Ket(0), 0.5], [Ket(1), 0.5]))
@SKIP("TODO: sympy.physics.quantum.shor: Cmod Not Implemented")
def test_sympy__physics__quantum__shor__CMod():
from sympy.physics.quantum.shor import CMod
assert _test_args(CMod())
def test_sympy__physics__quantum__spin__CoupledSpinState():
from sympy.physics.quantum.spin import CoupledSpinState
assert _test_args(CoupledSpinState(1, 0, (1, 1)))
assert _test_args(CoupledSpinState(1, 0, (1, S(1)/2, S(1)/2)))
assert _test_args(CoupledSpinState(
1, 0, (1, S(1)/2, S(1)/2), ((2, 3, S(1)/2), (1, 2, 1)) ))
j, m, j1, j2, j3, j12, x = symbols('j m j1:4 j12 x')
assert CoupledSpinState(
j, m, (j1, j2, j3)).subs(j2, x) == CoupledSpinState(j, m, (j1, x, j3))
assert CoupledSpinState(j, m, (j1, j2, j3), ((1, 3, j12), (1, 2, j)) ).subs(j12, x) == \
CoupledSpinState(j, m, (j1, j2, j3), ((1, 3, x), (1, 2, j)) )
def test_sympy__physics__quantum__spin__J2Op():
from sympy.physics.quantum.spin import J2Op
assert _test_args(J2Op('J'))
def test_sympy__physics__quantum__spin__JminusOp():
from sympy.physics.quantum.spin import JminusOp
assert _test_args(JminusOp('J'))
def test_sympy__physics__quantum__spin__JplusOp():
from sympy.physics.quantum.spin import JplusOp
assert _test_args(JplusOp('J'))
def test_sympy__physics__quantum__spin__JxBra():
from sympy.physics.quantum.spin import JxBra
assert _test_args(JxBra(1, 0))
def test_sympy__physics__quantum__spin__JxBraCoupled():
from sympy.physics.quantum.spin import JxBraCoupled
assert _test_args(JxBraCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JxKet():
from sympy.physics.quantum.spin import JxKet
assert _test_args(JxKet(1, 0))
def test_sympy__physics__quantum__spin__JxKetCoupled():
from sympy.physics.quantum.spin import JxKetCoupled
assert _test_args(JxKetCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JxOp():
from sympy.physics.quantum.spin import JxOp
assert _test_args(JxOp('J'))
def test_sympy__physics__quantum__spin__JyBra():
from sympy.physics.quantum.spin import JyBra
assert _test_args(JyBra(1, 0))
def test_sympy__physics__quantum__spin__JyBraCoupled():
from sympy.physics.quantum.spin import JyBraCoupled
assert _test_args(JyBraCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JyKet():
from sympy.physics.quantum.spin import JyKet
assert _test_args(JyKet(1, 0))
def test_sympy__physics__quantum__spin__JyKetCoupled():
from sympy.physics.quantum.spin import JyKetCoupled
assert _test_args(JyKetCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JyOp():
from sympy.physics.quantum.spin import JyOp
assert _test_args(JyOp('J'))
def test_sympy__physics__quantum__spin__JzBra():
from sympy.physics.quantum.spin import JzBra
assert _test_args(JzBra(1, 0))
def test_sympy__physics__quantum__spin__JzBraCoupled():
from sympy.physics.quantum.spin import JzBraCoupled
assert _test_args(JzBraCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JzKet():
from sympy.physics.quantum.spin import JzKet
assert _test_args(JzKet(1, 0))
def test_sympy__physics__quantum__spin__JzKetCoupled():
from sympy.physics.quantum.spin import JzKetCoupled
assert _test_args(JzKetCoupled(1, 0, (1, 1)))
def test_sympy__physics__quantum__spin__JzOp():
from sympy.physics.quantum.spin import JzOp
assert _test_args(JzOp('J'))
def test_sympy__physics__quantum__spin__Rotation():
from sympy.physics.quantum.spin import Rotation
assert _test_args(Rotation(pi, 0, pi/2))
def test_sympy__physics__quantum__spin__SpinState():
from sympy.physics.quantum.spin import SpinState
assert _test_args(SpinState(1, 0))
def test_sympy__physics__quantum__spin__WignerD():
from sympy.physics.quantum.spin import WignerD
assert _test_args(WignerD(0, 1, 2, 3, 4, 5))
def test_sympy__physics__quantum__state__Bra():
from sympy.physics.quantum.state import Bra
assert _test_args(Bra(0))
def test_sympy__physics__quantum__state__BraBase():
from sympy.physics.quantum.state import BraBase
assert _test_args(BraBase(0))
def test_sympy__physics__quantum__state__Ket():
from sympy.physics.quantum.state import Ket
assert _test_args(Ket(0))
def test_sympy__physics__quantum__state__KetBase():
from sympy.physics.quantum.state import KetBase
assert _test_args(KetBase(0))
def test_sympy__physics__quantum__state__State():
from sympy.physics.quantum.state import State
assert _test_args(State(0))
def test_sympy__physics__quantum__state__StateBase():
from sympy.physics.quantum.state import StateBase
assert _test_args(StateBase(0))
def test_sympy__physics__quantum__state__TimeDepBra():
from sympy.physics.quantum.state import TimeDepBra
assert _test_args(TimeDepBra('psi', 't'))
def test_sympy__physics__quantum__state__TimeDepKet():
from sympy.physics.quantum.state import TimeDepKet
assert _test_args(TimeDepKet('psi', 't'))
def test_sympy__physics__quantum__state__TimeDepState():
from sympy.physics.quantum.state import TimeDepState
assert _test_args(TimeDepState('psi', 't'))
def test_sympy__physics__quantum__state__Wavefunction():
from sympy.physics.quantum.state import Wavefunction
from sympy.functions import sin
from sympy import Piecewise
n = 1
L = 1
g = Piecewise((0, x < 0), (0, x > L), (sqrt(2//L)*sin(n*pi*x/L), True))
assert _test_args(Wavefunction(g, x))
def test_sympy__physics__quantum__tensorproduct__TensorProduct():
from sympy.physics.quantum.tensorproduct import TensorProduct
assert _test_args(TensorProduct(x, y))
def test_sympy__physics__quantum__identitysearch__GateIdentity():
from sympy.physics.quantum.gate import X
from sympy.physics.quantum.identitysearch import GateIdentity
assert _test_args(GateIdentity(X(0), X(0)))
def test_sympy__physics__quantum__sho1d__SHOOp():
from sympy.physics.quantum.sho1d import SHOOp
assert _test_args(SHOOp('a'))
def test_sympy__physics__quantum__sho1d__RaisingOp():
from sympy.physics.quantum.sho1d import RaisingOp
assert _test_args(RaisingOp('a'))
def test_sympy__physics__quantum__sho1d__LoweringOp():
from sympy.physics.quantum.sho1d import LoweringOp
assert _test_args(LoweringOp('a'))
def test_sympy__physics__quantum__sho1d__NumberOp():
from sympy.physics.quantum.sho1d import NumberOp
assert _test_args(NumberOp('N'))
def test_sympy__physics__quantum__sho1d__Hamiltonian():
from sympy.physics.quantum.sho1d import Hamiltonian
assert _test_args(Hamiltonian('H'))
def test_sympy__physics__quantum__sho1d__SHOState():
from sympy.physics.quantum.sho1d import SHOState
assert _test_args(SHOState(0))
def test_sympy__physics__quantum__sho1d__SHOKet():
from sympy.physics.quantum.sho1d import SHOKet
assert _test_args(SHOKet(0))
def test_sympy__physics__quantum__sho1d__SHOBra():
from sympy.physics.quantum.sho1d import SHOBra
assert _test_args(SHOBra(0))
def test_sympy__physics__secondquant__AnnihilateBoson():
from sympy.physics.secondquant import AnnihilateBoson
assert _test_args(AnnihilateBoson(0))
def test_sympy__physics__secondquant__AnnihilateFermion():
from sympy.physics.secondquant import AnnihilateFermion
assert _test_args(AnnihilateFermion(0))
@SKIP("abstract class")
def test_sympy__physics__secondquant__Annihilator():
pass
def test_sympy__physics__secondquant__AntiSymmetricTensor():
from sympy.physics.secondquant import AntiSymmetricTensor
i, j = symbols('i j', below_fermi=True)
a, b = symbols('a b', above_fermi=True)
assert _test_args(AntiSymmetricTensor('v', (a, i), (b, j)))
def test_sympy__physics__secondquant__BosonState():
from sympy.physics.secondquant import BosonState
assert _test_args(BosonState((0, 1)))
@SKIP("abstract class")
def test_sympy__physics__secondquant__BosonicOperator():
pass
def test_sympy__physics__secondquant__Commutator():
from sympy.physics.secondquant import Commutator
assert _test_args(Commutator(x, y))
def test_sympy__physics__secondquant__CreateBoson():
from sympy.physics.secondquant import CreateBoson
assert _test_args(CreateBoson(0))
def test_sympy__physics__secondquant__CreateFermion():
from sympy.physics.secondquant import CreateFermion
assert _test_args(CreateFermion(0))
@SKIP("abstract class")
def test_sympy__physics__secondquant__Creator():
pass
def test_sympy__physics__secondquant__Dagger():
from sympy.physics.secondquant import Dagger
from sympy import I
assert _test_args(Dagger(2*I))
def test_sympy__physics__secondquant__FermionState():
from sympy.physics.secondquant import FermionState
assert _test_args(FermionState((0, 1)))
def test_sympy__physics__secondquant__FermionicOperator():
from sympy.physics.secondquant import FermionicOperator
assert _test_args(FermionicOperator(0))
def test_sympy__physics__secondquant__FockState():
from sympy.physics.secondquant import FockState
assert _test_args(FockState((0, 1)))
def test_sympy__physics__secondquant__FockStateBosonBra():
from sympy.physics.secondquant import FockStateBosonBra
assert _test_args(FockStateBosonBra((0, 1)))
def test_sympy__physics__secondquant__FockStateBosonKet():
from sympy.physics.secondquant import FockStateBosonKet
assert _test_args(FockStateBosonKet((0, 1)))
def test_sympy__physics__secondquant__FockStateBra():
from sympy.physics.secondquant import FockStateBra
assert _test_args(FockStateBra((0, 1)))
def test_sympy__physics__secondquant__FockStateFermionBra():
from sympy.physics.secondquant import FockStateFermionBra
assert _test_args(FockStateFermionBra((0, 1)))
def test_sympy__physics__secondquant__FockStateFermionKet():
from sympy.physics.secondquant import FockStateFermionKet
assert _test_args(FockStateFermionKet((0, 1)))
def test_sympy__physics__secondquant__FockStateKet():
from sympy.physics.secondquant import FockStateKet
assert _test_args(FockStateKet((0, 1)))
def test_sympy__physics__secondquant__InnerProduct():
from sympy.physics.secondquant import InnerProduct
from sympy.physics.secondquant import FockStateKet, FockStateBra
assert _test_args(InnerProduct(FockStateBra((0, 1)), FockStateKet((0, 1))))
def test_sympy__physics__secondquant__NO():
from sympy.physics.secondquant import NO, F, Fd
assert _test_args(NO(Fd(x)*F(y)))
def test_sympy__physics__secondquant__PermutationOperator():
from sympy.physics.secondquant import PermutationOperator
assert _test_args(PermutationOperator(0, 1))
def test_sympy__physics__secondquant__SqOperator():
from sympy.physics.secondquant import SqOperator
assert _test_args(SqOperator(0))
def test_sympy__physics__secondquant__TensorSymbol():
from sympy.physics.secondquant import TensorSymbol
assert _test_args(TensorSymbol(x))
def test_sympy__physics__units__dimensions__Dimension():
from sympy.physics.units.dimensions import Dimension
assert _test_args(Dimension("length", "L"))
def test_sympy__physics__units__dimensions__DimensionSystem():
from sympy.physics.units.dimensions import DimensionSystem
from sympy.physics.units.dimensions import length, time, velocity
assert _test_args(DimensionSystem((length, time), (velocity,)))
def test_sympy__physics__units__quantities__Quantity():
from sympy.physics.units.quantities import Quantity
from sympy.physics.units import length
assert _test_args(Quantity("dam"))
def test_sympy__physics__units__prefixes__Prefix():
from sympy.physics.units.prefixes import Prefix
assert _test_args(Prefix('kilo', 'k', 3))
def test_sympy__core__numbers__AlgebraicNumber():
from sympy.core.numbers import AlgebraicNumber
assert _test_args(AlgebraicNumber(sqrt(2), [1, 2, 3]))
def test_sympy__polys__polytools__GroebnerBasis():
from sympy.polys.polytools import GroebnerBasis
assert _test_args(GroebnerBasis([x, y, z], x, y, z))
def test_sympy__polys__polytools__Poly():
from sympy.polys.polytools import Poly
assert _test_args(Poly(2, x, y))
def test_sympy__polys__polytools__PurePoly():
from sympy.polys.polytools import PurePoly
assert _test_args(PurePoly(2, x, y))
@SKIP('abstract class')
def test_sympy__polys__rootoftools__RootOf():
pass
def test_sympy__polys__rootoftools__ComplexRootOf():
from sympy.polys.rootoftools import ComplexRootOf
assert _test_args(ComplexRootOf(x**3 + x + 1, 0))
def test_sympy__polys__rootoftools__RootSum():
from sympy.polys.rootoftools import RootSum
assert _test_args(RootSum(x**3 + x + 1, sin))
def test_sympy__series__limits__Limit():
from sympy.series.limits import Limit
assert _test_args(Limit(x, x, 0, dir='-'))
def test_sympy__series__order__Order():
from sympy.series.order import Order
assert _test_args(Order(1, x, y))
@SKIP('Abstract Class')
def test_sympy__series__sequences__SeqBase():
pass
def test_sympy__series__sequences__EmptySequence():
from sympy.series.sequences import EmptySequence
assert _test_args(EmptySequence())
@SKIP('Abstract Class')
def test_sympy__series__sequences__SeqExpr():
pass
def test_sympy__series__sequences__SeqPer():
from sympy.series.sequences import SeqPer
assert _test_args(SeqPer((1, 2, 3), (0, 10)))
def test_sympy__series__sequences__SeqFormula():
from sympy.series.sequences import SeqFormula
assert _test_args(SeqFormula(x**2, (0, 10)))
def test_sympy__series__sequences__RecursiveSeq():
from sympy.series.sequences import RecursiveSeq
y = Function("y")
n = symbols("n")
assert _test_args(RecursiveSeq(y(n - 1) + y(n - 2), y, n, (0, 1)))
assert _test_args(RecursiveSeq(y(n - 1) + y(n - 2), y, n))
def test_sympy__series__sequences__SeqExprOp():
from sympy.series.sequences import SeqExprOp, sequence
s1 = sequence((1, 2, 3))
s2 = sequence(x**2)
assert _test_args(SeqExprOp(s1, s2))
def test_sympy__series__sequences__SeqAdd():
from sympy.series.sequences import SeqAdd, sequence
s1 = sequence((1, 2, 3))
s2 = sequence(x**2)
assert _test_args(SeqAdd(s1, s2))
def test_sympy__series__sequences__SeqMul():
from sympy.series.sequences import SeqMul, sequence
s1 = sequence((1, 2, 3))
s2 = sequence(x**2)
assert _test_args(SeqMul(s1, s2))
@SKIP('Abstract Class')
def test_sympy__series__series_class__SeriesBase():
pass
def test_sympy__series__fourier__FourierSeries():
from sympy.series.fourier import fourier_series
assert _test_args(fourier_series(x, (x, -pi, pi)))
def test_sympy__series__formal__FormalPowerSeries():
from sympy.series.formal import fps
assert _test_args(fps(log(1 + x), x))
def test_sympy__simplify__hyperexpand__Hyper_Function():
from sympy.simplify.hyperexpand import Hyper_Function
assert _test_args(Hyper_Function([2], [1]))
def test_sympy__simplify__hyperexpand__G_Function():
from sympy.simplify.hyperexpand import G_Function
assert _test_args(G_Function([2], [1], [], []))
@SKIP("abstract class")
def test_sympy__tensor__array__ndim_array__ImmutableNDimArray():
pass
def test_sympy__tensor__array__dense_ndim_array__ImmutableDenseNDimArray():
from sympy.tensor.array.dense_ndim_array import ImmutableDenseNDimArray
densarr = ImmutableDenseNDimArray(range(10, 34), (2, 3, 4))
assert _test_args(densarr)
def test_sympy__tensor__array__sparse_ndim_array__ImmutableSparseNDimArray():
from sympy.tensor.array.sparse_ndim_array import ImmutableSparseNDimArray
sparr = ImmutableSparseNDimArray(range(10, 34), (2, 3, 4))
assert _test_args(sparr)
def test_sympy__tensor__functions__TensorProduct():
from sympy.tensor.functions import TensorProduct
tp = TensorProduct(3, 4, evaluate=False)
assert _test_args(tp)
def test_sympy__tensor__indexed__Idx():
from sympy.tensor.indexed import Idx
assert _test_args(Idx('test'))
assert _test_args(Idx(1, (0, 10)))
def test_sympy__tensor__indexed__Indexed():
from sympy.tensor.indexed import Indexed, Idx
assert _test_args(Indexed('A', Idx('i'), Idx('j')))
def test_sympy__tensor__indexed__IndexedBase():
from sympy.tensor.indexed import IndexedBase
assert _test_args(IndexedBase('A', shape=(x, y)))
assert _test_args(IndexedBase('A', 1))
assert _test_args(IndexedBase('A')[0, 1])
def test_sympy__tensor__tensor__TensorIndexType():
from sympy.tensor.tensor import TensorIndexType
assert _test_args(TensorIndexType('Lorentz', metric=False))
def test_sympy__tensor__tensor__TensorSymmetry():
from sympy.tensor.tensor import TensorSymmetry, get_symmetric_group_sgs
assert _test_args(TensorSymmetry(get_symmetric_group_sgs(2)))
def test_sympy__tensor__tensor__TensorType():
from sympy.tensor.tensor import TensorIndexType, TensorSymmetry, get_symmetric_group_sgs, TensorType
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
sym = TensorSymmetry(get_symmetric_group_sgs(1))
assert _test_args(TensorType([Lorentz], sym))
def test_sympy__tensor__tensor__TensorHead():
from sympy.tensor.tensor import TensorIndexType, TensorSymmetry, TensorType, get_symmetric_group_sgs, TensorHead
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
sym = TensorSymmetry(get_symmetric_group_sgs(1))
S1 = TensorType([Lorentz], sym)
assert _test_args(TensorHead('p', S1, 0))
def test_sympy__tensor__tensor__TensorIndex():
from sympy.tensor.tensor import TensorIndexType, TensorIndex
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
assert _test_args(TensorIndex('i', Lorentz))
@SKIP("abstract class")
def test_sympy__tensor__tensor__TensExpr():
pass
def test_sympy__tensor__tensor__TensAdd():
from sympy.tensor.tensor import TensorIndexType, TensorSymmetry, TensorType, get_symmetric_group_sgs, tensor_indices, TensAdd
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
a, b = tensor_indices('a,b', Lorentz)
sym = TensorSymmetry(get_symmetric_group_sgs(1))
S1 = TensorType([Lorentz], sym)
p, q = S1('p,q')
t1 = p(a)
t2 = q(a)
assert _test_args(TensAdd(t1, t2))
def test_sympy__tensor__tensor__Tensor():
from sympy.core import S
from sympy.tensor.tensor import TensorIndexType, TensorSymmetry, TensorType, get_symmetric_group_sgs, tensor_indices, TensMul
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
a, b = tensor_indices('a,b', Lorentz)
sym = TensorSymmetry(get_symmetric_group_sgs(1))
S1 = TensorType([Lorentz], sym)
p = S1('p')
assert _test_args(p(a))
def test_sympy__tensor__tensor__TensMul():
from sympy.core import S
from sympy.tensor.tensor import TensorIndexType, TensorSymmetry, TensorType, get_symmetric_group_sgs, tensor_indices, TensMul
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
a, b = tensor_indices('a,b', Lorentz)
sym = TensorSymmetry(get_symmetric_group_sgs(1))
S1 = TensorType([Lorentz], sym)
p = S1('p')
q = S1('q')
assert _test_args(3*p(a)*q(b))
def test_sympy__tensor__tensor__TensorElement():
from sympy.tensor.tensor import TensorIndexType, tensorhead, TensorElement
L = TensorIndexType("L")
A = tensorhead("A", [L, L], [[1], [1]])
telem = TensorElement(A(x, y), {x: 1})
assert _test_args(telem)
def test_sympy__tensor__toperators__PartialDerivative():
from sympy.tensor.tensor import TensorIndexType, tensor_indices, tensorhead
from sympy.tensor.toperators import PartialDerivative
Lorentz = TensorIndexType('Lorentz', dummy_fmt='L')
a, b = tensor_indices('a,b', Lorentz)
A = tensorhead("A", [Lorentz], [[1]])
assert _test_args(PartialDerivative(A(a), A(b)))
def test_as_coeff_add():
assert (7, (3*x, 4*x**2)) == (7 + 3*x + 4*x**2).as_coeff_add()
def test_sympy__geometry__curve__Curve():
from sympy.geometry.curve import Curve
assert _test_args(Curve((x, 1), (x, 0, 1)))
def test_sympy__geometry__point__Point():
from sympy.geometry.point import Point
assert _test_args(Point(0, 1))
def test_sympy__geometry__point__Point2D():
from sympy.geometry.point import Point2D
assert _test_args(Point2D(0, 1))
def test_sympy__geometry__point__Point3D():
from sympy.geometry.point import Point3D
assert _test_args(Point3D(0, 1, 2))
def test_sympy__geometry__ellipse__Ellipse():
from sympy.geometry.ellipse import Ellipse
assert _test_args(Ellipse((0, 1), 2, 3))
def test_sympy__geometry__ellipse__Circle():
from sympy.geometry.ellipse import Circle
assert _test_args(Circle((0, 1), 2))
def test_sympy__geometry__parabola__Parabola():
from sympy.geometry.parabola import Parabola
from sympy.geometry.line import Line
assert _test_args(Parabola((0, 0), Line((2, 3), (4, 3))))
@SKIP("abstract class")
def test_sympy__geometry__line__LinearEntity():
pass
def test_sympy__geometry__line__Line():
from sympy.geometry.line import Line
assert _test_args(Line((0, 1), (2, 3)))
def test_sympy__geometry__line__Ray():
from sympy.geometry.line import Ray
assert _test_args(Ray((0, 1), (2, 3)))
def test_sympy__geometry__line__Segment():
from sympy.geometry.line import Segment
assert _test_args(Segment((0, 1), (2, 3)))
@SKIP("abstract class")
def test_sympy__geometry__line__LinearEntity2D():
pass
def test_sympy__geometry__line__Line2D():
from sympy.geometry.line import Line2D
assert _test_args(Line2D((0, 1), (2, 3)))
def test_sympy__geometry__line__Ray2D():
from sympy.geometry.line import Ray2D
assert _test_args(Ray2D((0, 1), (2, 3)))
def test_sympy__geometry__line__Segment2D():
from sympy.geometry.line import Segment2D
assert _test_args(Segment2D((0, 1), (2, 3)))
@SKIP("abstract class")
def test_sympy__geometry__line__LinearEntity3D():
pass
def test_sympy__geometry__line__Line3D():
from sympy.geometry.line import Line3D
assert _test_args(Line3D((0, 1, 1), (2, 3, 4)))
def test_sympy__geometry__line__Segment3D():
from sympy.geometry.line import Segment3D
assert _test_args(Segment3D((0, 1, 1), (2, 3, 4)))
def test_sympy__geometry__line__Ray3D():
from sympy.geometry.line import Ray3D
assert _test_args(Ray3D((0, 1, 1), (2, 3, 4)))
def test_sympy__geometry__plane__Plane():
from sympy.geometry.plane import Plane
assert _test_args(Plane((1, 1, 1), (-3, 4, -2), (1, 2, 3)))
def test_sympy__geometry__polygon__Polygon():
from sympy.geometry.polygon import Polygon
assert _test_args(Polygon((0, 1), (2, 3), (4, 5), (6, 7)))
def test_sympy__geometry__polygon__RegularPolygon():
from sympy.geometry.polygon import RegularPolygon
assert _test_args(RegularPolygon((0, 1), 2, 3, 4))
def test_sympy__geometry__polygon__Triangle():
from sympy.geometry.polygon import Triangle
assert _test_args(Triangle((0, 1), (2, 3), (4, 5)))
def test_sympy__geometry__entity__GeometryEntity():
from sympy.geometry.entity import GeometryEntity
from sympy.geometry.point import Point
assert _test_args(GeometryEntity(Point(1, 0), 1, [1, 2]))
@SKIP("abstract class")
def test_sympy__geometry__entity__GeometrySet():
pass
def test_sympy__diffgeom__diffgeom__Manifold():
from sympy.diffgeom import Manifold
assert _test_args(Manifold('name', 3))
def test_sympy__diffgeom__diffgeom__Patch():
from sympy.diffgeom import Manifold, Patch
assert _test_args(Patch('name', Manifold('name', 3)))
def test_sympy__diffgeom__diffgeom__CoordSystem():
from sympy.diffgeom import Manifold, Patch, CoordSystem
assert _test_args(CoordSystem('name', Patch('name', Manifold('name', 3))))
@XFAIL
def test_sympy__diffgeom__diffgeom__Point():
from sympy.diffgeom import Manifold, Patch, CoordSystem, Point
assert _test_args(Point(
CoordSystem('name', Patch('name', Manifold('name', 3))), [x, y]))
def test_sympy__diffgeom__diffgeom__BaseScalarField():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseScalarField
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
assert _test_args(BaseScalarField(cs, 0))
def test_sympy__diffgeom__diffgeom__BaseVectorField():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseVectorField
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
assert _test_args(BaseVectorField(cs, 0))
def test_sympy__diffgeom__diffgeom__Differential():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseScalarField, Differential
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
assert _test_args(Differential(BaseScalarField(cs, 0)))
def test_sympy__diffgeom__diffgeom__Commutator():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseVectorField, Commutator
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
cs1 = CoordSystem('name1', Patch('name', Manifold('name', 3)))
v = BaseVectorField(cs, 0)
v1 = BaseVectorField(cs1, 0)
assert _test_args(Commutator(v, v1))
def test_sympy__diffgeom__diffgeom__TensorProduct():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseScalarField, Differential, TensorProduct
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
d = Differential(BaseScalarField(cs, 0))
assert _test_args(TensorProduct(d, d))
def test_sympy__diffgeom__diffgeom__WedgeProduct():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseScalarField, Differential, WedgeProduct
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
d = Differential(BaseScalarField(cs, 0))
d1 = Differential(BaseScalarField(cs, 1))
assert _test_args(WedgeProduct(d, d1))
def test_sympy__diffgeom__diffgeom__LieDerivative():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseScalarField, Differential, BaseVectorField, LieDerivative
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
d = Differential(BaseScalarField(cs, 0))
v = BaseVectorField(cs, 0)
assert _test_args(LieDerivative(v, d))
@XFAIL
def test_sympy__diffgeom__diffgeom__BaseCovarDerivativeOp():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseCovarDerivativeOp
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
assert _test_args(BaseCovarDerivativeOp(cs, 0, [[[0, ]*3, ]*3, ]*3))
def test_sympy__diffgeom__diffgeom__CovarDerivativeOp():
from sympy.diffgeom import Manifold, Patch, CoordSystem, BaseVectorField, CovarDerivativeOp
cs = CoordSystem('name', Patch('name', Manifold('name', 3)))
v = BaseVectorField(cs, 0)
_test_args(CovarDerivativeOp(v, [[[0, ]*3, ]*3, ]*3))
def test_sympy__categories__baseclasses__Class():
from sympy.categories.baseclasses import Class
assert _test_args(Class())
def test_sympy__categories__baseclasses__Object():
from sympy.categories import Object
assert _test_args(Object("A"))
@XFAIL
def test_sympy__categories__baseclasses__Morphism():
from sympy.categories import Object, Morphism
assert _test_args(Morphism(Object("A"), Object("B")))
def test_sympy__categories__baseclasses__IdentityMorphism():
from sympy.categories import Object, IdentityMorphism
assert _test_args(IdentityMorphism(Object("A")))
def test_sympy__categories__baseclasses__NamedMorphism():
from sympy.categories import Object, NamedMorphism
assert _test_args(NamedMorphism(Object("A"), Object("B"), "f"))
def test_sympy__categories__baseclasses__CompositeMorphism():
from sympy.categories import Object, NamedMorphism, CompositeMorphism
A = Object("A")
B = Object("B")
C = Object("C")
f = NamedMorphism(A, B, "f")
g = NamedMorphism(B, C, "g")
assert _test_args(CompositeMorphism(f, g))
def test_sympy__categories__baseclasses__Diagram():
from sympy.categories import Object, NamedMorphism, Diagram
A = Object("A")
B = Object("B")
C = Object("C")
f = NamedMorphism(A, B, "f")
d = Diagram([f])
assert _test_args(d)
def test_sympy__categories__baseclasses__Category():
from sympy.categories import Object, NamedMorphism, Diagram, Category
A = Object("A")
B = Object("B")
C = Object("C")
f = NamedMorphism(A, B, "f")
g = NamedMorphism(B, C, "g")
d1 = Diagram([f, g])
d2 = Diagram([f])
K = Category("K", commutative_diagrams=[d1, d2])
assert _test_args(K)
def test_sympy__ntheory__factor___totient():
from sympy.ntheory.factor_ import totient
k = symbols('k', integer=True)
t = totient(k)
assert _test_args(t)
def test_sympy__ntheory__factor___reduced_totient():
from sympy.ntheory.factor_ import reduced_totient
k = symbols('k', integer=True)
t = reduced_totient(k)
assert _test_args(t)
def test_sympy__ntheory__factor___divisor_sigma():
from sympy.ntheory.factor_ import divisor_sigma
k = symbols('k', integer=True)
n = symbols('n', integer=True)
t = divisor_sigma(n, k)
assert _test_args(t)
def test_sympy__ntheory__factor___udivisor_sigma():
from sympy.ntheory.factor_ import udivisor_sigma
k = symbols('k', integer=True)
n = symbols('n', integer=True)
t = udivisor_sigma(n, k)
assert _test_args(t)
def test_sympy__ntheory__factor___primenu():
from sympy.ntheory.factor_ import primenu
n = symbols('n', integer=True)
t = primenu(n)
assert _test_args(t)
def test_sympy__ntheory__factor___primeomega():
from sympy.ntheory.factor_ import primeomega
n = symbols('n', integer=True)
t = primeomega(n)
assert _test_args(t)
def test_sympy__ntheory__residue_ntheory__mobius():
from sympy.ntheory import mobius
assert _test_args(mobius(2))
def test_sympy__ntheory__generate__primepi():
from sympy.ntheory import primepi
n = symbols('n')
t = primepi(n)
assert _test_args(t)
def test_sympy__physics__optics__waves__TWave():
from sympy.physics.optics import TWave
A, f, phi = symbols('A, f, phi')
assert _test_args(TWave(A, f, phi))
def test_sympy__physics__optics__gaussopt__BeamParameter():
from sympy.physics.optics import BeamParameter
assert _test_args(BeamParameter(530e-9, 1, w=1e-3))
def test_sympy__physics__optics__medium__Medium():
from sympy.physics.optics import Medium
assert _test_args(Medium('m'))
def test_sympy__codegen__array_utils__CodegenArrayContraction():
from sympy.codegen.array_utils import CodegenArrayContraction
from sympy import IndexedBase
A = symbols("A", cls=IndexedBase)
assert _test_args(CodegenArrayContraction(A, (0, 1)))
def test_sympy__codegen__array_utils__CodegenArrayDiagonal():
from sympy.codegen.array_utils import CodegenArrayDiagonal
from sympy import IndexedBase
A = symbols("A", cls=IndexedBase)
assert _test_args(CodegenArrayDiagonal(A, (0, 1)))
def test_sympy__codegen__array_utils__CodegenArrayTensorProduct():
from sympy.codegen.array_utils import CodegenArrayTensorProduct
from sympy import IndexedBase
A, B = symbols("A B", cls=IndexedBase)
assert _test_args(CodegenArrayTensorProduct(A, B))
def test_sympy__codegen__array_utils__CodegenArrayElementwiseAdd():
from sympy.codegen.array_utils import CodegenArrayElementwiseAdd
from sympy import IndexedBase
A, B = symbols("A B", cls=IndexedBase)
assert _test_args(CodegenArrayElementwiseAdd(A, B))
def test_sympy__codegen__array_utils__CodegenArrayPermuteDims():
from sympy.codegen.array_utils import CodegenArrayPermuteDims
from sympy import IndexedBase
A = symbols("A", cls=IndexedBase)
assert _test_args(CodegenArrayPermuteDims(A, (1, 0)))
def test_sympy__codegen__ast__Assignment():
from sympy.codegen.ast import Assignment
assert _test_args(Assignment(x, y))
def test_sympy__codegen__cfunctions__expm1():
from sympy.codegen.cfunctions import expm1
assert _test_args(expm1(x))
def test_sympy__codegen__cfunctions__log1p():
from sympy.codegen.cfunctions import log1p
assert _test_args(log1p(x))
def test_sympy__codegen__cfunctions__exp2():
from sympy.codegen.cfunctions import exp2
assert _test_args(exp2(x))
def test_sympy__codegen__cfunctions__log2():
from sympy.codegen.cfunctions import log2
assert _test_args(log2(x))
def test_sympy__codegen__cfunctions__fma():
from sympy.codegen.cfunctions import fma
assert _test_args(fma(x, y, z))
def test_sympy__codegen__cfunctions__log10():
from sympy.codegen.cfunctions import log10
assert _test_args(log10(x))
def test_sympy__codegen__cfunctions__Sqrt():
from sympy.codegen.cfunctions import Sqrt
assert _test_args(Sqrt(x))
def test_sympy__codegen__cfunctions__Cbrt():
from sympy.codegen.cfunctions import Cbrt
assert _test_args(Cbrt(x))
def test_sympy__codegen__cfunctions__hypot():
from sympy.codegen.cfunctions import hypot
assert _test_args(hypot(x, y))
def test_sympy__codegen__fnodes__FFunction():
from sympy.codegen.fnodes import FFunction
assert _test_args(FFunction('f'))
def test_sympy__codegen__fnodes__F95Function():
from sympy.codegen.fnodes import F95Function
assert _test_args(F95Function('f'))
def test_sympy__codegen__fnodes__isign():
from sympy.codegen.fnodes import isign
assert _test_args(isign(1, x))
def test_sympy__codegen__fnodes__dsign():
from sympy.codegen.fnodes import dsign
assert _test_args(dsign(1, x))
def test_sympy__codegen__fnodes__cmplx():
from sympy.codegen.fnodes import cmplx
assert _test_args(cmplx(x, y))
def test_sympy__codegen__fnodes__kind():
from sympy.codegen.fnodes import kind
assert _test_args(kind(x))
def test_sympy__codegen__fnodes__merge():
from sympy.codegen.fnodes import merge
assert _test_args(merge(1, 2, Eq(x, 0)))
def test_sympy__codegen__fnodes___literal():
from sympy.codegen.fnodes import _literal
assert _test_args(_literal(1))
def test_sympy__codegen__fnodes__literal_sp():
from sympy.codegen.fnodes import literal_sp
assert _test_args(literal_sp(1))
def test_sympy__codegen__fnodes__literal_dp():
from sympy.codegen.fnodes import literal_dp
assert _test_args(literal_dp(1))
def test_sympy__vector__coordsysrect__CoordSys3D():
from sympy.vector.coordsysrect import CoordSys3D
assert _test_args(CoordSys3D('C'))
def test_sympy__vector__point__Point():
from sympy.vector.point import Point
assert _test_args(Point('P'))
def test_sympy__vector__basisdependent__BasisDependent():
from sympy.vector.basisdependent import BasisDependent
#These classes have been created to maintain an OOP hierarchy
#for Vectors and Dyadics. Are NOT meant to be initialized
def test_sympy__vector__basisdependent__BasisDependentMul():
from sympy.vector.basisdependent import BasisDependentMul
#These classes have been created to maintain an OOP hierarchy
#for Vectors and Dyadics. Are NOT meant to be initialized
def test_sympy__vector__basisdependent__BasisDependentAdd():
from sympy.vector.basisdependent import BasisDependentAdd
#These classes have been created to maintain an OOP hierarchy
#for Vectors and Dyadics. Are NOT meant to be initialized
def test_sympy__vector__basisdependent__BasisDependentZero():
from sympy.vector.basisdependent import BasisDependentZero
#These classes have been created to maintain an OOP hierarchy
#for Vectors and Dyadics. Are NOT meant to be initialized
def test_sympy__vector__vector__BaseVector():
from sympy.vector.vector import BaseVector
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(BaseVector(0, C, ' ', ' '))
def test_sympy__vector__vector__VectorAdd():
from sympy.vector.vector import VectorAdd, VectorMul
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
from sympy.abc import a, b, c, x, y, z
v1 = a*C.i + b*C.j + c*C.k
v2 = x*C.i + y*C.j + z*C.k
assert _test_args(VectorAdd(v1, v2))
assert _test_args(VectorMul(x, v1))
def test_sympy__vector__vector__VectorMul():
from sympy.vector.vector import VectorMul
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
from sympy.abc import a
assert _test_args(VectorMul(a, C.i))
def test_sympy__vector__vector__VectorZero():
from sympy.vector.vector import VectorZero
assert _test_args(VectorZero())
def test_sympy__vector__vector__Vector():
from sympy.vector.vector import Vector
#Vector is never to be initialized using args
pass
def test_sympy__vector__vector__Cross():
from sympy.vector.vector import Cross
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
_test_args(Cross(C.i, C.j))
def test_sympy__vector__vector__Dot():
from sympy.vector.vector import Dot
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
_test_args(Dot(C.i, C.j))
def test_sympy__vector__dyadic__Dyadic():
from sympy.vector.dyadic import Dyadic
#Dyadic is never to be initialized using args
pass
def test_sympy__vector__dyadic__BaseDyadic():
from sympy.vector.dyadic import BaseDyadic
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(BaseDyadic(C.i, C.j))
def test_sympy__vector__dyadic__DyadicMul():
from sympy.vector.dyadic import BaseDyadic, DyadicMul
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(DyadicMul(3, BaseDyadic(C.i, C.j)))
def test_sympy__vector__dyadic__DyadicAdd():
from sympy.vector.dyadic import BaseDyadic, DyadicAdd
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(2 * DyadicAdd(BaseDyadic(C.i, C.i),
BaseDyadic(C.i, C.j)))
def test_sympy__vector__dyadic__DyadicZero():
from sympy.vector.dyadic import DyadicZero
assert _test_args(DyadicZero())
def test_sympy__vector__deloperator__Del():
from sympy.vector.deloperator import Del
assert _test_args(Del())
def test_sympy__vector__operators__Curl():
from sympy.vector.operators import Curl
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(Curl(C.i))
def test_sympy__vector__operators__Divergence():
from sympy.vector.operators import Divergence
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(Divergence(C.i))
def test_sympy__vector__operators__Gradient():
from sympy.vector.operators import Gradient
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(Gradient(C.x))
def test_sympy__vector__orienters__Orienter():
from sympy.vector.orienters import Orienter
#Not to be initialized
def test_sympy__vector__orienters__ThreeAngleOrienter():
from sympy.vector.orienters import ThreeAngleOrienter
#Not to be initialized
def test_sympy__vector__orienters__AxisOrienter():
from sympy.vector.orienters import AxisOrienter
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(AxisOrienter(x, C.i))
def test_sympy__vector__orienters__BodyOrienter():
from sympy.vector.orienters import BodyOrienter
assert _test_args(BodyOrienter(x, y, z, '123'))
def test_sympy__vector__orienters__SpaceOrienter():
from sympy.vector.orienters import SpaceOrienter
assert _test_args(SpaceOrienter(x, y, z, '123'))
def test_sympy__vector__orienters__QuaternionOrienter():
from sympy.vector.orienters import QuaternionOrienter
a, b, c, d = symbols('a b c d')
assert _test_args(QuaternionOrienter(a, b, c, d))
def test_sympy__vector__scalar__BaseScalar():
from sympy.vector.scalar import BaseScalar
from sympy.vector.coordsysrect import CoordSys3D
C = CoordSys3D('C')
assert _test_args(BaseScalar(0, C, ' ', ' '))
def test_sympy__physics__wigner__Wigner3j():
from sympy.physics.wigner import Wigner3j
assert _test_args(Wigner3j(0, 0, 0, 0, 0, 0))
def test_sympy__integrals__rubi__symbol__matchpyWC():
from sympy.integrals.rubi.symbol import matchpyWC
assert _test_args(matchpyWC(1, True, 'a'))
def test_sympy__integrals__rubi__utility_function__rubi_unevaluated_expr():
from sympy.integrals.rubi.utility_function import rubi_unevaluated_expr
a = symbols('a')
assert _test_args(rubi_unevaluated_expr(a))
def test_sympy__integrals__rubi__utility_function__exp():
from sympy.integrals.rubi.utility_function import exp
assert _test_args(exp(5))
def test_sympy__integrals__rubi__utility_function__log():
from sympy.integrals.rubi.utility_function import log
assert _test_args(log(5))
def test_sympy__integrals__rubi__utility_function__Int():
from sympy.integrals.rubi.utility_function import Int
assert _test_args(Int(5, x))
def test_sympy__integrals__rubi__utility_function__Util_Coefficient():
from sympy.integrals.rubi.utility_function import Util_Coefficient
a, x = symbols('a x')
assert _test_args(Util_Coefficient(a, x))
def test_sympy__integrals__rubi__utility_function__Gamma():
from sympy.integrals.rubi.utility_function import Gamma
assert _test_args(Gamma(5))
def test_sympy__integrals__rubi__utility_function__Util_Part():
from sympy.integrals.rubi.utility_function import Util_Part
a, b = symbols('a b')
assert _test_args(Util_Part(a + b, 0))
def test_sympy__integrals__rubi__utility_function__PolyGamma():
from sympy.integrals.rubi.utility_function import PolyGamma
assert _test_args(PolyGamma(1, 1))
def test_sympy__integrals__rubi__utility_function__ProductLog():
from sympy.integrals.rubi.utility_function import ProductLog
assert _test_args(ProductLog(1))
|
0889f809a72b3b102c7b2ac74b6c19e0d6854fe30fd55e6b5f57f0054bdfaf7d
|
from sympy import (S, Symbol, sqrt, I, Integer, Rational, cos, sin, im, re, Abs,
exp, sinh, cosh, tan, tanh, conjugate, sign, cot, coth, pi, symbols,
expand_complex)
def test_complex():
a = Symbol("a", real=True)
b = Symbol("b", real=True)
e = (a + I*b)*(a - I*b)
assert e.expand() == a**2 + b**2
assert sqrt(I) == sqrt(I)
def test_conjugate():
a = Symbol("a", real=True)
b = Symbol("b", real=True)
c = Symbol("c", imaginary=True)
d = Symbol("d", imaginary=True)
x = Symbol('x')
z = a + I*b + c + I*d
zc = a - I*b - c + I*d
assert conjugate(z) == zc
assert conjugate(exp(z)) == exp(zc)
assert conjugate(exp(I*x)) == exp(-I*conjugate(x))
assert conjugate(z**5) == zc**5
assert conjugate(abs(x)) == abs(x)
assert conjugate(sign(z)) == sign(zc)
assert conjugate(sin(z)) == sin(zc)
assert conjugate(cos(z)) == cos(zc)
assert conjugate(tan(z)) == tan(zc)
assert conjugate(cot(z)) == cot(zc)
assert conjugate(sinh(z)) == sinh(zc)
assert conjugate(cosh(z)) == cosh(zc)
assert conjugate(tanh(z)) == tanh(zc)
assert conjugate(coth(z)) == coth(zc)
def test_abs1():
a = Symbol("a", real=True)
b = Symbol("b", real=True)
assert abs(a) == abs(a)
assert abs(-a) == abs(a)
assert abs(a + I*b) == sqrt(a**2 + b**2)
def test_abs2():
a = Symbol("a", real=False)
b = Symbol("b", real=False)
assert abs(a) != a
assert abs(-a) != a
assert abs(a + I*b) != sqrt(a**2 + b**2)
def test_evalc():
x = Symbol("x", real=True)
y = Symbol("y", real=True)
z = Symbol("z")
assert ((x + I*y)**2).expand(complex=True) == x**2 + 2*I*x*y - y**2
assert expand_complex(z**(2*I)) == (re((re(z) + I*im(z))**(2*I)) +
I*im((re(z) + I*im(z))**(2*I)))
assert expand_complex(
z**(2*I), deep=False) == I*im(z**(2*I)) + re(z**(2*I))
assert exp(I*x) != cos(x) + I*sin(x)
assert exp(I*x).expand(complex=True) == cos(x) + I*sin(x)
assert exp(I*x + y).expand(complex=True) == exp(y)*cos(x) + I*sin(x)*exp(y)
assert sin(I*x).expand(complex=True) == I * sinh(x)
assert sin(x + I*y).expand(complex=True) == sin(x)*cosh(y) + \
I * sinh(y) * cos(x)
assert cos(I*x).expand(complex=True) == cosh(x)
assert cos(x + I*y).expand(complex=True) == cos(x)*cosh(y) - \
I * sinh(y) * sin(x)
assert tan(I*x).expand(complex=True) == tanh(x) * I
assert tan(x + I*y).expand(complex=True) == (
sin(2*x)/(cos(2*x) + cosh(2*y)) +
I*sinh(2*y)/(cos(2*x) + cosh(2*y)))
assert sinh(I*x).expand(complex=True) == I * sin(x)
assert sinh(x + I*y).expand(complex=True) == sinh(x)*cos(y) + \
I * sin(y) * cosh(x)
assert cosh(I*x).expand(complex=True) == cos(x)
assert cosh(x + I*y).expand(complex=True) == cosh(x)*cos(y) + \
I * sin(y) * sinh(x)
assert tanh(I*x).expand(complex=True) == tan(x) * I
assert tanh(x + I*y).expand(complex=True) == (
(sinh(x)*cosh(x) + I*cos(y)*sin(y)) /
(sinh(x)**2 + cos(y)**2)).expand()
def test_pythoncomplex():
x = Symbol("x")
assert 4j*x == 4*x*I
assert 4j*x == 4.0*x*I
assert 4.1j*x != 4*x*I
def test_rootcomplex():
R = Rational
assert ((+1 + I)**R(1, 2)).expand(
complex=True) == 2**R(1, 4)*cos( pi/8) + 2**R(1, 4)*sin( pi/8)*I
assert ((-1 - I)**R(1, 2)).expand(
complex=True) == 2**R(1, 4)*cos(3*pi/8) - 2**R(1, 4)*sin(3*pi/8)*I
assert (sqrt(-10)*I).as_real_imag() == (-sqrt(10), 0)
def test_expand_inverse():
assert (1/(1 + I)).expand(complex=True) == (1 - I)/2
assert ((1 + 2*I)**(-2)).expand(complex=True) == (-3 - 4*I)/25
assert ((1 + I)**(-8)).expand(complex=True) == Rational(1, 16)
def test_expand_complex():
assert ((2 + 3*I)**10).expand(complex=True) == -341525 - 145668*I
# the following two tests are to ensure the SymPy uses an efficient
# algorithm for calculating powers of complex numbers. They should execute
# in something like 0.01s.
assert ((2 + 3*I)**1000).expand(complex=True) == \
-81079464736246615951519029367296227340216902563389546989376269312984127074385455204551402940331021387412262494620336565547972162814110386834027871072723273110439771695255662375718498785908345629702081336606863762777939617745464755635193139022811989314881997210583159045854968310911252660312523907616129080027594310008539817935736331124833163907518549408018652090650537035647520296539436440394920287688149200763245475036722326561143851304795139005599209239350981457301460233967137708519975586996623552182807311159141501424576682074392689622074945519232029999 + \
46938745946789557590804551905243206242164799136976022474337918748798900569942573265747576032611189047943842446167719177749107138603040963603119861476016947257034472364028585381714774667326478071264878108114128915685688115488744955550920239128462489496563930809677159214598114273887061533057125164518549173898349061972857446844052995037423459472376202251620778517659247970283904820245958198842631651569984310559418135975795868314764489884749573052997832686979294085577689571149679540256349988338406458116270429842222666345146926395233040564229555893248370000*I
assert ((2 + 3*I/4)**1000).expand(complex=True) == \
Integer(1)*37079892761199059751745775382463070250205990218394308874593455293485167797989691280095867197640410033222367257278387021789651672598831503296531725827158233077451476545928116965316544607115843772405184272449644892857783761260737279675075819921259597776770965829089907990486964515784097181964312256560561065607846661496055417619388874421218472707497847700629822858068783288579581649321248495739224020822198695759609598745114438265083593711851665996586461937988748911532242908776883696631067311443171682974330675406616373422505939887984366289623091300746049101284856530270685577940283077888955692921951247230006346681086274961362500646889925803654263491848309446197554307105991537357310209426736453173441104334496173618419659521888945605315751089087820455852582920963561495787655250624781448951403353654348109893478206364632640344111022531861683064175862889459084900614967785405977231549003280842218501570429860550379522498497412180001/114813069527425452423283320117768198402231770208869520047764273682576626139237031385665948631650626991844596463898746277344711896086305533142593135616665318539129989145312280000688779148240044871428926990063486244781615463646388363947317026040466353970904996558162398808944629605623311649536164221970332681344168908984458505602379484807914058900934776500429002716706625830522008132236281291761267883317206598995396418127021779858404042159853183251540889433902091920554957783589672039160081957216630582755380425583726015528348786419432054508915275783882625175435528800822842770817965453762184851149029376 + \
I*421638390580169706973991429333213477486930178424989246669892530737775352519112934278994501272111385966211392610029433824534634841747911783746811994443436271013377059560245191441549885048056920190833693041257216263519792201852046825443439142932464031501882145407459174948712992271510309541474392303461939389368955986650538525895866713074543004916049550090364398070215427272240155060576252568700906004691224321432509053286859100920489253598392100207663785243368195857086816912514025693453058403158416856847185079684216151337200057494966741268925263085619240941610301610538225414050394612058339070756009433535451561664522479191267503989904464718368605684297071150902631208673621618217106272361061676184840810762902463998065947687814692402219182668782278472952758690939877465065070481351343206840649517150634973307937551168752642148704904383991876969408056379195860410677814566225456558230131911142229028179902418223009651437985670625/1793954211366022694113801876840128100034871409513586250746316776290259783425578615401030447369541046747571819748417910583511123376348523955353017744010395602173906080395504375010762174191250701116076984219741972574712741619474818186676828531882286780795390571221287481389759837587864244524002565968286448146002639202882164150037179450123657170327105882819203167448541028601906377066191895183769810676831353109303069033234715310287563158747705988305326397404720186258671215368588625611876280581509852855552819149745718992630449787803625851701801184123166018366180137512856918294030710215034138299203584
assert ((2 + 3*I)**-1000).expand(complex=True) == \
Integer(1)*-81079464736246615951519029367296227340216902563389546989376269312984127074385455204551402940331021387412262494620336565547972162814110386834027871072723273110439771695255662375718498785908345629702081336606863762777939617745464755635193139022811989314881997210583159045854968310911252660312523907616129080027594310008539817935736331124833163907518549408018652090650537035647520296539436440394920287688149200763245475036722326561143851304795139005599209239350981457301460233967137708519975586996623552182807311159141501424576682074392689622074945519232029999/8777125472973511649630750050295188683351430110097915876250894978429797369155961290321829625004920141758416719066805645579710744290541337680113772670040386863849283653078324415471816788604945889094925784900885812724984087843737442111926413818245854362613018058774368703971604921858023116665586358870612944209398056562604561248859926344335598822815885851096698226775053153403320782439987679978321289537645645163767251396759519805603090332694449553371530571613352311006350058217982509738362083094920649452123351717366337410243853659113315547584871655479914439219520157174729130746351059075207407866012574386726064196992865627149566238044625779078186624347183905913357718850537058578084932880569701242598663149911276357125355850792073635533676541250531086757377369962506979378337216411188347761901006460813413505861461267545723590468627854202034450569581626648934062198718362303420281555886394558137408159453103395918783625713213314350531051312551733021627153081075080140680608080529736975658786227362251632725009435866547613598753584705455955419696609282059191031962604169242974038517575645939316377801594539335940001 - Integer(1)*46938745946789557590804551905243206242164799136976022474337918748798900569942573265747576032611189047943842446167719177749107138603040963603119861476016947257034472364028585381714774667326478071264878108114128915685688115488744955550920239128462489496563930809677159214598114273887061533057125164518549173898349061972857446844052995037423459472376202251620778517659247970283904820245958198842631651569984310559418135975795868314764489884749573052997832686979294085577689571149679540256349988338406458116270429842222666345146926395233040564229555893248370000*I/8777125472973511649630750050295188683351430110097915876250894978429797369155961290321829625004920141758416719066805645579710744290541337680113772670040386863849283653078324415471816788604945889094925784900885812724984087843737442111926413818245854362613018058774368703971604921858023116665586358870612944209398056562604561248859926344335598822815885851096698226775053153403320782439987679978321289537645645163767251396759519805603090332694449553371530571613352311006350058217982509738362083094920649452123351717366337410243853659113315547584871655479914439219520157174729130746351059075207407866012574386726064196992865627149566238044625779078186624347183905913357718850537058578084932880569701242598663149911276357125355850792073635533676541250531086757377369962506979378337216411188347761901006460813413505861461267545723590468627854202034450569581626648934062198718362303420281555886394558137408159453103395918783625713213314350531051312551733021627153081075080140680608080529736975658786227362251632725009435866547613598753584705455955419696609282059191031962604169242974038517575645939316377801594539335940001
assert ((2 + 3*I/4)**-1000).expand(complex=True) == \
Integer(1)*4257256305661027385394552848555894604806501409793288342610746813288539790051927148781268212212078237301273165351052934681382567968787279534591114913777456610214738290619922068269909423637926549603264174216950025398244509039145410016404821694746262142525173737175066432954496592560621330313807235750500564940782099283410261748370262433487444897446779072067625787246390824312580440138770014838135245148574339248259670887549732495841810961088930810608893772914812838358159009303794863047635845688453859317690488124382253918725010358589723156019888846606295866740117645571396817375322724096486161308083462637370825829567578309445855481578518239186117686659177284332344643124760453112513611749309168470605289172320376911472635805822082051716625171429727162039621902266619821870482519063133136820085579315127038372190224739238686708451840610064871885616258831386810233957438253532027049148030157164346719204500373766157143311767338973363806106967439378604898250533766359989107510507493549529158818602327525235240510049484816090584478644771183158342479140194633579061295740839490629457435283873180259847394582069479062820225159699506175855369539201399183443253793905149785994830358114153241481884290274629611529758663543080724574566578220908907477622643689220814376054314972190402285121776593824615083669045183404206291739005554569305329760211752815718335731118664756831942466773261465213581616104242113894521054475516019456867271362053692785300826523328020796670205463390909136593859765912483565093461468865534470710132881677639651348709376/2103100954337624833663208713697737151593634525061637972297915388685604042449504336765884978184588688426595940401280828953096857809292320006227881797146858511436638446932833617514351442216409828605662238790280753075176269765767010004889778647709740770757817960711900340755635772183674511158570690702969774966791073165467918123298694584729211212414462628433370481195120564586361368504153395406845170075275051749019600057116719726628746724489572189061061036426955163696859127711110719502594479795200686212257570291758725259007379710596548777812659422174199194837355646482046783616494013289495563083118517507178847555801163089723056310287760875135196081975602765511153122381201303871673391366630940702817360340900568748719988954847590748960761446218262344767250783946365392689256634180417145926390656439421745644011831124277463643383712803287985472471755648426749842410972650924240795946699346613614779460399530274263580007672855851663196114585312432954432654691485867618908420370875753749297487803461900447407917655296784879220450937110470920633595689721819488638484547259978337741496090602390463594556401615298457456112485536498177883358587125449801777718900375736758266215245325999241624148841915093787519330809347240990363802360596034171167818310322276373120180985148650099673289383722502488957717848531612020897298448601714154586319660314294591620415272119454982220034319689607295960162971300417552364254983071768070124456169427638371140064235083443242844616326538396503937972586505546495649094344512270582463639152160238137952390380581401171977159154009407415523525096743009110916334144716516647041176989758534635251844947906038080852185583742296318878233394998111078843229681030277039104786225656992262073797524057992347971177720807155842376332851559276430280477639539393920006008737472164850104411971830120295750221200029811143140323763349636629725073624360001 - Integer(1)*3098214262599218784594285246258841485430681674561917573155883806818465520660668045042109232930382494608383663464454841313154390741655282039877410154577448327874989496074260116195788919037407420625081798124301494353693248757853222257918294662198297114746822817460991242508743651430439120439020484502408313310689912381846149597061657483084652685283853595100434135149479564507015504022249330340259111426799121454516345905101620532787348293877485702600390665276070250119465888154331218827342488849948540687659846652377277250614246402784754153678374932540789808703029043827352976139228402417432199779415751301480406673762521987999573209628597459357964214510139892316208670927074795773830798600837815329291912002136924506221066071242281626618211060464126372574400100990746934953437169840312584285942093951405864225230033279614235191326102697164613004299868695519642598882914862568516635347204441042798206770888274175592401790040170576311989738272102077819127459014286741435419468254146418098278519775722104890854275995510700298782146199325790002255362719776098816136732897323406228294203133323296591166026338391813696715894870956511298793595675308998014158717167429941371979636895553724830981754579086664608880698350866487717403917070872269853194118364230971216854931998642990452908852258008095741042117326241406479532880476938937997238098399302185675832474590293188864060116934035867037219176916416481757918864533515526389079998129329045569609325290897577497835388451456680707076072624629697883854217331728051953671643278797380171857920000*I/2103100954337624833663208713697737151593634525061637972297915388685604042449504336765884978184588688426595940401280828953096857809292320006227881797146858511436638446932833617514351442216409828605662238790280753075176269765767010004889778647709740770757817960711900340755635772183674511158570690702969774966791073165467918123298694584729211212414462628433370481195120564586361368504153395406845170075275051749019600057116719726628746724489572189061061036426955163696859127711110719502594479795200686212257570291758725259007379710596548777812659422174199194837355646482046783616494013289495563083118517507178847555801163089723056310287760875135196081975602765511153122381201303871673391366630940702817360340900568748719988954847590748960761446218262344767250783946365392689256634180417145926390656439421745644011831124277463643383712803287985472471755648426749842410972650924240795946699346613614779460399530274263580007672855851663196114585312432954432654691485867618908420370875753749297487803461900447407917655296784879220450937110470920633595689721819488638484547259978337741496090602390463594556401615298457456112485536498177883358587125449801777718900375736758266215245325999241624148841915093787519330809347240990363802360596034171167818310322276373120180985148650099673289383722502488957717848531612020897298448601714154586319660314294591620415272119454982220034319689607295960162971300417552364254983071768070124456169427638371140064235083443242844616326538396503937972586505546495649094344512270582463639152160238137952390380581401171977159154009407415523525096743009110916334144716516647041176989758534635251844947906038080852185583742296318878233394998111078843229681030277039104786225656992262073797524057992347971177720807155842376332851559276430280477639539393920006008737472164850104411971830120295750221200029811143140323763349636629725073624360001
a = Symbol('a', real=True)
b = Symbol('b', real=True)
assert exp(a*(2 + I*b)).expand(complex=True) == \
I*exp(2*a)*sin(a*b) + exp(2*a)*cos(a*b)
def test_expand():
f = (16 - 2*sqrt(29))**2
assert f.expand() == 372 - 64*sqrt(29)
f = (Integer(1)/2 + I/2)**10
assert f.expand() == I/32
f = (Integer(1)/2 + I)**10
assert f.expand() == Integer(237)/1024 - 779*I/256
def test_re_im1652():
x = Symbol('x')
assert re(x) == re(conjugate(x))
assert im(x) == - im(conjugate(x))
assert im(x)*re(conjugate(x)) + im(conjugate(x)) * re(x) == 0
def test_issue_5084():
x = Symbol('x')
assert ((x + x*I)/(1 + I)).as_real_imag() == (re((x + I*x)/(1 + I)
), im((x + I*x)/(1 + I)))
def test_issue_5236():
assert (cos(1 + I)**3).as_real_imag() == (-3*sin(1)**2*sinh(1)**2*cos(1)*cosh(1) +
cos(1)**3*cosh(1)**3, -3*cos(1)**2*cosh(1)**2*sin(1)*sinh(1) + sin(1)**3*sinh(1)**3)
def test_real_imag():
x, y, z = symbols('x, y, z')
X, Y, Z = symbols('X, Y, Z', commutative=False)
a = Symbol('a', real=True)
assert (2*a*x).as_real_imag() == (2*a*re(x), 2*a*im(x))
# issue 5395:
assert (x*x.conjugate()).as_real_imag() == (Abs(x)**2, 0)
assert im(x*x.conjugate()) == 0
assert im(x*y.conjugate()*z*y) == im(x*z)*Abs(y)**2
assert im(x*y.conjugate()*x*y) == im(x**2)*Abs(y)**2
assert im(Z*y.conjugate()*X*y) == im(Z*X)*Abs(y)**2
assert im(X*X.conjugate()) == im(X*X.conjugate(), evaluate=False)
assert (sin(x)*sin(x).conjugate()).as_real_imag() == \
(Abs(sin(x))**2, 0)
# issue 6573:
assert (x**2).as_real_imag() == (re(x)**2 - im(x)**2, 2*re(x)*im(x))
# issue 6428:
r = Symbol('r', real=True)
i = Symbol('i', imaginary=True)
assert (i*r*x).as_real_imag() == (I*i*r*im(x), -I*i*r*re(x))
assert (i*r*x*(y + 2)).as_real_imag() == (
I*i*r*(re(y) + 2)*im(x) + I*i*r*re(x)*im(y),
-I*i*r*(re(y) + 2)*re(x) + I*i*r*im(x)*im(y))
# issue 7106:
assert ((1 + I)/(1 - I)).as_real_imag() == (0, 1)
assert ((1 + 2*I)*(1 + 3*I)).as_real_imag() == (-5, 5)
def test_pow_issue_1724():
e = ((-1)**(S(1)/3))
assert e.conjugate().n() == e.n().conjugate()
e = S('-2/3 - (-29/54 + sqrt(93)/18)**(1/3) - 1/(9*(-29/54 + sqrt(93)/18)**(1/3))')
assert e.conjugate().n() == e.n().conjugate()
e = 2**I
assert e.conjugate().n() == e.n().conjugate()
def test_issue_5429():
assert sqrt(I).conjugate() != sqrt(I)
def test_issue_4124():
from sympy import oo
assert expand_complex(I*oo) == oo*I
def test_issue_11518():
x = Symbol("x", real=True)
y = Symbol("y", real=True)
r = sqrt(x**2 + y**2)
assert conjugate(r) == r
s = abs(x + I * y)
assert conjugate(s) == r
|
80958b466606622038e79404c5f8c32882199d28b90f951f3ff3cf8d2d5af9d5
|
from sympy import (Basic, Symbol, sin, cos, exp, sqrt, Rational, Float, re, pi,
sympify, Add, Mul, Pow, Mod, I, log, S, Max, symbols, oo, zoo, Integer,
sign, im, nan, Dummy, factorial, comp, refine
)
from sympy.core.compatibility import long, range
from sympy.utilities.iterables import cartes
from sympy.utilities.pytest import XFAIL, raises
from sympy.utilities.randtest import verify_numerically
a, c, x, y, z = symbols('a,c,x,y,z')
b = Symbol("b", positive=True)
def same_and_same_prec(a, b):
# stricter matching for Floats
return a == b and a._prec == b._prec
def test_bug1():
assert re(x) != x
x.series(x, 0, 1)
assert re(x) != x
def test_Symbol():
e = a*b
assert e == a*b
assert a*b*b == a*b**2
assert a*b*b + c == c + a*b**2
assert a*b*b - c == -c + a*b**2
x = Symbol('x', complex=True, real=False)
assert x.is_imaginary is None # could be I or 1 + I
x = Symbol('x', complex=True, imaginary=False)
assert x.is_real is None # could be 1 or 1 + I
x = Symbol('x', real=True)
assert x.is_complex
x = Symbol('x', imaginary=True)
assert x.is_complex
x = Symbol('x', real=False, imaginary=False)
assert x.is_complex is None # might be a non-number
def test_arit0():
p = Rational(5)
e = a*b
assert e == a*b
e = a*b + b*a
assert e == 2*a*b
e = a*b + b*a + a*b + p*b*a
assert e == 8*a*b
e = a*b + b*a + a*b + p*b*a + a
assert e == a + 8*a*b
e = a + a
assert e == 2*a
e = a + b + a
assert e == b + 2*a
e = a + b*b + a + b*b
assert e == 2*a + 2*b**2
e = a + Rational(2) + b*b + a + b*b + p
assert e == 7 + 2*a + 2*b**2
e = (a + b*b + a + b*b)*p
assert e == 5*(2*a + 2*b**2)
e = (a*b*c + c*b*a + b*a*c)*p
assert e == 15*a*b*c
e = (a*b*c + c*b*a + b*a*c)*p - Rational(15)*a*b*c
assert e == Rational(0)
e = Rational(50)*(a - a)
assert e == Rational(0)
e = b*a - b - a*b + b
assert e == Rational(0)
e = a*b + c**p
assert e == a*b + c**5
e = a/b
assert e == a*b**(-1)
e = a*2*2
assert e == 4*a
e = 2 + a*2/2
assert e == 2 + a
e = 2 - a - 2
assert e == -a
e = 2*a*2
assert e == 4*a
e = 2/a/2
assert e == a**(-1)
e = 2**a**2
assert e == 2**(a**2)
e = -(1 + a)
assert e == -1 - a
e = Rational(1, 2)*(1 + a)
assert e == Rational(1, 2) + a/2
def test_div():
e = a/b
assert e == a*b**(-1)
e = a/b + c/2
assert e == a*b**(-1) + Rational(1)/2*c
e = (1 - b)/(b - 1)
assert e == (1 + -b)*((-1) + b)**(-1)
def test_pow():
n1 = Rational(1)
n2 = Rational(2)
n5 = Rational(5)
e = a*a
assert e == a**2
e = a*a*a
assert e == a**3
e = a*a*a*a**Rational(6)
assert e == a**9
e = a*a*a*a**Rational(6) - a**Rational(9)
assert e == Rational(0)
e = a**(b - b)
assert e == Rational(1)
e = (a + Rational(1) - a)**b
assert e == Rational(1)
e = (a + b + c)**n2
assert e == (a + b + c)**2
assert e.expand() == 2*b*c + 2*a*c + 2*a*b + a**2 + c**2 + b**2
e = (a + b)**n2
assert e == (a + b)**2
assert e.expand() == 2*a*b + a**2 + b**2
e = (a + b)**(n1/n2)
assert e == sqrt(a + b)
assert e.expand() == sqrt(a + b)
n = n5**(n1/n2)
assert n == sqrt(5)
e = n*a*b - n*b*a
assert e == Rational(0)
e = n*a*b + n*b*a
assert e == 2*a*b*sqrt(5)
assert e.diff(a) == 2*b*sqrt(5)
assert e.diff(a) == 2*b*sqrt(5)
e = a/b**2
assert e == a*b**(-2)
assert sqrt(2*(1 + sqrt(2))) == (2*(1 + 2**Rational(1, 2)))**Rational(1, 2)
x = Symbol('x')
y = Symbol('y')
assert ((x*y)**3).expand() == y**3 * x**3
assert ((x*y)**-3).expand() == y**-3 * x**-3
assert (x**5*(3*x)**(3)).expand() == 27 * x**8
assert (x**5*(-3*x)**(3)).expand() == -27 * x**8
assert (x**5*(3*x)**(-3)).expand() == Rational(1, 27) * x**2
assert (x**5*(-3*x)**(-3)).expand() == -Rational(1, 27) * x**2
# expand_power_exp
assert (x**(y**(x + exp(x + y)) + z)).expand(deep=False) == \
x**z*x**(y**(x + exp(x + y)))
assert (x**(y**(x + exp(x + y)) + z)).expand() == \
x**z*x**(y**x*y**(exp(x)*exp(y)))
n = Symbol('n', even=False)
k = Symbol('k', even=True)
o = Symbol('o', odd=True)
assert (-1)**x == (-1)**x
assert (-1)**n == (-1)**n
assert (-2)**k == 2**k
assert (-1)**k == 1
def test_pow2():
# x**(2*y) is always (x**y)**2 but is only (x**2)**y if
# x.is_positive or y.is_integer
# let x = 1 to see why the following are not true.
assert (-x)**Rational(2, 3) != x**Rational(2, 3)
assert (-x)**Rational(5, 7) != -x**Rational(5, 7)
assert ((-x)**2)**Rational(1, 3) != ((-x)**Rational(1, 3))**2
assert sqrt(x**2) != x
def test_pow3():
assert sqrt(2)**3 == 2 * sqrt(2)
assert sqrt(2)**3 == sqrt(8)
def test_mod_pow():
for s, t, u, v in [(4, 13, 497, 445), (4, -3, 497, 365),
(3.2, 2.1, 1.9, 0.1031015682350942), (S(3)/2, 5, S(5)/6, S(3)/32)]:
assert pow(S(s), t, u) == v
assert pow(S(s), S(t), u) == v
assert pow(S(s), t, S(u)) == v
assert pow(S(s), S(t), S(u)) == v
assert pow(S(2), S(10000000000), S(3)) == 1
assert pow(x, y, z) == x**y%z
raises(TypeError, lambda: pow(S(4), "13", 497))
raises(TypeError, lambda: pow(S(4), 13, "497"))
def test_pow_E():
assert 2**(y/log(2)) == S.Exp1**y
assert 2**(y/log(2)/3) == S.Exp1**(y/3)
assert 3**(1/log(-3)) != S.Exp1
assert (3 + 2*I)**(1/(log(-3 - 2*I) + I*pi)) == S.Exp1
assert (4 + 2*I)**(1/(log(-4 - 2*I) + I*pi)) == S.Exp1
assert (3 + 2*I)**(1/(log(-3 - 2*I, 3)/2 + I*pi/log(3)/2)) == 9
assert (3 + 2*I)**(1/(log(3 + 2*I, 3)/2)) == 9
# every time tests are run they will affirm with a different random
# value that this identity holds
while 1:
b = x._random()
r, i = b.as_real_imag()
if i:
break
assert verify_numerically(b**(1/(log(-b) + sign(i)*I*pi).n()), S.Exp1)
def test_pow_issue_3516():
assert 4**Rational(1, 4) == sqrt(2)
def test_pow_im():
for m in (-2, -1, 2):
for d in (3, 4, 5):
b = m*I
for i in range(1, 4*d + 1):
e = Rational(i, d)
assert (b**e - b.n()**e.n()).n(2, chop=1e-10) == 0
e = Rational(7, 3)
assert (2*x*I)**e == 4*2**Rational(1, 3)*(I*x)**e # same as Wolfram Alpha
im = symbols('im', imaginary=True)
assert (2*im*I)**e == 4*2**Rational(1, 3)*(I*im)**e
args = [I, I, I, I, 2]
e = Rational(1, 3)
ans = 2**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args = [I, I, I, 2]
e = Rational(1, 3)
ans = 2**e*(-I)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args.append(-3)
ans = (6*I)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args.append(-1)
ans = (-6*I)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args = [I, I, 2]
e = Rational(1, 3)
ans = (-2)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args.append(-3)
ans = (6)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
args.append(-1)
ans = (-6)**e
assert Mul(*args, evaluate=False)**e == ans
assert Mul(*args)**e == ans
assert Mul(Pow(-1, Rational(3, 2), evaluate=False), I, I) == I
assert Mul(I*Pow(I, S.Half, evaluate=False)) == sqrt(I)*I
def test_real_mul():
assert Float(0) * pi * x == Float(0)
assert set((Float(1) * pi * x).args) == {Float(1), pi, x}
def test_ncmul():
A = Symbol("A", commutative=False)
B = Symbol("B", commutative=False)
C = Symbol("C", commutative=False)
assert A*B != B*A
assert A*B*C != C*B*A
assert A*b*B*3*C == 3*b*A*B*C
assert A*b*B*3*C != 3*b*B*A*C
assert A*b*B*3*C == 3*A*B*C*b
assert A + B == B + A
assert (A + B)*C != C*(A + B)
assert C*(A + B)*C != C*C*(A + B)
assert A*A == A**2
assert (A + B)*(A + B) == (A + B)**2
assert A**-1 * A == 1
assert A/A == 1
assert A/(A**2) == 1/A
assert A/(1 + A) == A/(1 + A)
assert set((A + B + 2*(A + B)).args) == \
{A, B, 2*(A + B)}
def test_ncpow():
x = Symbol('x', commutative=False)
y = Symbol('y', commutative=False)
z = Symbol('z', commutative=False)
a = Symbol('a')
b = Symbol('b')
c = Symbol('c')
assert (x**2)*(y**2) != (y**2)*(x**2)
assert (x**-2)*y != y*(x**2)
assert 2**x*2**y != 2**(x + y)
assert 2**x*2**y*2**z != 2**(x + y + z)
assert 2**x*2**(2*x) == 2**(3*x)
assert 2**x*2**(2*x)*2**x == 2**(4*x)
assert exp(x)*exp(y) != exp(y)*exp(x)
assert exp(x)*exp(y)*exp(z) != exp(y)*exp(x)*exp(z)
assert exp(x)*exp(y)*exp(z) != exp(x + y + z)
assert x**a*x**b != x**(a + b)
assert x**a*x**b*x**c != x**(a + b + c)
assert x**3*x**4 == x**7
assert x**3*x**4*x**2 == x**9
assert x**a*x**(4*a) == x**(5*a)
assert x**a*x**(4*a)*x**a == x**(6*a)
def test_powerbug():
x = Symbol("x")
assert x**1 != (-x)**1
assert x**2 == (-x)**2
assert x**3 != (-x)**3
assert x**4 == (-x)**4
assert x**5 != (-x)**5
assert x**6 == (-x)**6
assert x**128 == (-x)**128
assert x**129 != (-x)**129
assert (2*x)**2 == (-2*x)**2
def test_Mul_doesnt_expand_exp():
x = Symbol('x')
y = Symbol('y')
assert exp(x)*exp(y) == exp(x)*exp(y)
assert 2**x*2**y == 2**x*2**y
assert x**2*x**3 == x**5
assert 2**x*3**x == 6**x
assert x**(y)*x**(2*y) == x**(3*y)
assert sqrt(2)*sqrt(2) == 2
assert 2**x*2**(2*x) == 2**(3*x)
assert sqrt(2)*2**Rational(1, 4)*5**Rational(3, 4) == 10**Rational(3, 4)
assert (x**(-log(5)/log(3))*x)/(x*x**( - log(5)/log(3))) == sympify(1)
def test_Add_Mul_is_integer():
x = Symbol('x')
k = Symbol('k', integer=True)
n = Symbol('n', integer=True)
assert (2*k).is_integer is True
assert (-k).is_integer is True
assert (k/3).is_integer is None
assert (x*k*n).is_integer is None
assert (k + n).is_integer is True
assert (k + x).is_integer is None
assert (k + n*x).is_integer is None
assert (k + n/3).is_integer is None
assert ((1 + sqrt(3))*(-sqrt(3) + 1)).is_integer is not False
assert (1 + (1 + sqrt(3))*(-sqrt(3) + 1)).is_integer is not False
def test_Add_Mul_is_finite():
x = Symbol('x', real=True, finite=False)
assert sin(x).is_finite is True
assert (x*sin(x)).is_finite is False
assert (1024*sin(x)).is_finite is True
assert (sin(x)*exp(x)).is_finite is not True
assert (sin(x)*cos(x)).is_finite is True
assert (x*sin(x)*exp(x)).is_finite is not True
assert (sin(x) - 67).is_finite is True
assert (sin(x) + exp(x)).is_finite is not True
assert (1 + x).is_finite is False
assert (1 + x**2 + (1 + x)*(1 - x)).is_finite is None
assert (sqrt(2)*(1 + x)).is_finite is False
assert (sqrt(2)*(1 + x)*(1 - x)).is_finite is False
def test_Mul_is_even_odd():
x = Symbol('x', integer=True)
y = Symbol('y', integer=True)
k = Symbol('k', odd=True)
n = Symbol('n', odd=True)
m = Symbol('m', even=True)
assert (2*x).is_even is True
assert (2*x).is_odd is False
assert (3*x).is_even is None
assert (3*x).is_odd is None
assert (k/3).is_integer is None
assert (k/3).is_even is None
assert (k/3).is_odd is None
assert (2*n).is_even is True
assert (2*n).is_odd is False
assert (2*m).is_even is True
assert (2*m).is_odd is False
assert (-n).is_even is False
assert (-n).is_odd is True
assert (k*n).is_even is False
assert (k*n).is_odd is True
assert (k*m).is_even is True
assert (k*m).is_odd is False
assert (k*n*m).is_even is True
assert (k*n*m).is_odd is False
assert (k*m*x).is_even is True
assert (k*m*x).is_odd is False
# issue 6791:
assert (x/2).is_integer is None
assert (k/2).is_integer is False
assert (m/2).is_integer is True
assert (x*y).is_even is None
assert (x*x).is_even is None
assert (x*(x + k)).is_even is True
assert (x*(x + m)).is_even is None
assert (x*y).is_odd is None
assert (x*x).is_odd is None
assert (x*(x + k)).is_odd is False
assert (x*(x + m)).is_odd is None
@XFAIL
def test_evenness_in_ternary_integer_product_with_odd():
# Tests that oddness inference is independent of term ordering.
# Term ordering at the point of testing depends on SymPy's symbol order, so
# we try to force a different order by modifying symbol names.
x = Symbol('x', integer=True)
y = Symbol('y', integer=True)
k = Symbol('k', odd=True)
assert (x*y*(y + k)).is_even is True
assert (y*x*(x + k)).is_even is True
def test_evenness_in_ternary_integer_product_with_even():
x = Symbol('x', integer=True)
y = Symbol('y', integer=True)
m = Symbol('m', even=True)
assert (x*y*(y + m)).is_even is None
@XFAIL
def test_oddness_in_ternary_integer_product_with_odd():
# Tests that oddness inference is independent of term ordering.
# Term ordering at the point of testing depends on SymPy's symbol order, so
# we try to force a different order by modifying symbol names.
x = Symbol('x', integer=True)
y = Symbol('y', integer=True)
k = Symbol('k', odd=True)
assert (x*y*(y + k)).is_odd is False
assert (y*x*(x + k)).is_odd is False
def test_oddness_in_ternary_integer_product_with_even():
x = Symbol('x', integer=True)
y = Symbol('y', integer=True)
m = Symbol('m', even=True)
assert (x*y*(y + m)).is_odd is None
def test_Mul_is_rational():
x = Symbol('x')
n = Symbol('n', integer=True)
m = Symbol('m', integer=True, nonzero=True)
assert (n/m).is_rational is True
assert (x/pi).is_rational is None
assert (x/n).is_rational is None
assert (m/pi).is_rational is False
r = Symbol('r', rational=True)
assert (pi*r).is_rational is None
# issue 8008
z = Symbol('z', zero=True)
i = Symbol('i', imaginary=True)
assert (z*i).is_rational is None
bi = Symbol('i', imaginary=True, finite=True)
assert (z*bi).is_zero is True
def test_Add_is_rational():
x = Symbol('x')
n = Symbol('n', rational=True)
m = Symbol('m', rational=True)
assert (n + m).is_rational is True
assert (x + pi).is_rational is None
assert (x + n).is_rational is None
assert (n + pi).is_rational is False
def test_Add_is_even_odd():
x = Symbol('x', integer=True)
k = Symbol('k', odd=True)
n = Symbol('n', odd=True)
m = Symbol('m', even=True)
assert (k + 7).is_even is True
assert (k + 7).is_odd is False
assert (-k + 7).is_even is True
assert (-k + 7).is_odd is False
assert (k - 12).is_even is False
assert (k - 12).is_odd is True
assert (-k - 12).is_even is False
assert (-k - 12).is_odd is True
assert (k + n).is_even is True
assert (k + n).is_odd is False
assert (k + m).is_even is False
assert (k + m).is_odd is True
assert (k + n + m).is_even is True
assert (k + n + m).is_odd is False
assert (k + n + x + m).is_even is None
assert (k + n + x + m).is_odd is None
def test_Mul_is_negative_positive():
x = Symbol('x', real=True)
y = Symbol('y', real=False, complex=True)
z = Symbol('z', zero=True)
e = 2*z
assert e.is_Mul and e.is_positive is False and e.is_negative is False
neg = Symbol('neg', negative=True)
pos = Symbol('pos', positive=True)
nneg = Symbol('nneg', nonnegative=True)
npos = Symbol('npos', nonpositive=True)
assert neg.is_negative is True
assert (-neg).is_negative is False
assert (2*neg).is_negative is True
assert (2*pos)._eval_is_negative() is False
assert (2*pos).is_negative is False
assert pos.is_negative is False
assert (-pos).is_negative is True
assert (2*pos).is_negative is False
assert (pos*neg).is_negative is True
assert (2*pos*neg).is_negative is True
assert (-pos*neg).is_negative is False
assert (pos*neg*y).is_negative is False # y.is_real=F; !real -> !neg
assert nneg.is_negative is False
assert (-nneg).is_negative is None
assert (2*nneg).is_negative is False
assert npos.is_negative is None
assert (-npos).is_negative is False
assert (2*npos).is_negative is None
assert (nneg*npos).is_negative is None
assert (neg*nneg).is_negative is None
assert (neg*npos).is_negative is False
assert (pos*nneg).is_negative is False
assert (pos*npos).is_negative is None
assert (npos*neg*nneg).is_negative is False
assert (npos*pos*nneg).is_negative is None
assert (-npos*neg*nneg).is_negative is None
assert (-npos*pos*nneg).is_negative is False
assert (17*npos*neg*nneg).is_negative is False
assert (17*npos*pos*nneg).is_negative is None
assert (neg*npos*pos*nneg).is_negative is False
assert (x*neg).is_negative is None
assert (nneg*npos*pos*x*neg).is_negative is None
assert neg.is_positive is False
assert (-neg).is_positive is True
assert (2*neg).is_positive is False
assert pos.is_positive is True
assert (-pos).is_positive is False
assert (2*pos).is_positive is True
assert (pos*neg).is_positive is False
assert (2*pos*neg).is_positive is False
assert (-pos*neg).is_positive is True
assert (-pos*neg*y).is_positive is False # y.is_real=F; !real -> !neg
assert nneg.is_positive is None
assert (-nneg).is_positive is False
assert (2*nneg).is_positive is None
assert npos.is_positive is False
assert (-npos).is_positive is None
assert (2*npos).is_positive is False
assert (nneg*npos).is_positive is False
assert (neg*nneg).is_positive is False
assert (neg*npos).is_positive is None
assert (pos*nneg).is_positive is None
assert (pos*npos).is_positive is False
assert (npos*neg*nneg).is_positive is None
assert (npos*pos*nneg).is_positive is False
assert (-npos*neg*nneg).is_positive is False
assert (-npos*pos*nneg).is_positive is None
assert (17*npos*neg*nneg).is_positive is None
assert (17*npos*pos*nneg).is_positive is False
assert (neg*npos*pos*nneg).is_positive is None
assert (x*neg).is_positive is None
assert (nneg*npos*pos*x*neg).is_positive is None
def test_Mul_is_negative_positive_2():
a = Symbol('a', nonnegative=True)
b = Symbol('b', nonnegative=True)
c = Symbol('c', nonpositive=True)
d = Symbol('d', nonpositive=True)
assert (a*b).is_nonnegative is True
assert (a*b).is_negative is False
assert (a*b).is_zero is None
assert (a*b).is_positive is None
assert (c*d).is_nonnegative is True
assert (c*d).is_negative is False
assert (c*d).is_zero is None
assert (c*d).is_positive is None
assert (a*c).is_nonpositive is True
assert (a*c).is_positive is False
assert (a*c).is_zero is None
assert (a*c).is_negative is None
def test_Mul_is_nonpositive_nonnegative():
x = Symbol('x', real=True)
k = Symbol('k', negative=True)
n = Symbol('n', positive=True)
u = Symbol('u', nonnegative=True)
v = Symbol('v', nonpositive=True)
assert k.is_nonpositive is True
assert (-k).is_nonpositive is False
assert (2*k).is_nonpositive is True
assert n.is_nonpositive is False
assert (-n).is_nonpositive is True
assert (2*n).is_nonpositive is False
assert (n*k).is_nonpositive is True
assert (2*n*k).is_nonpositive is True
assert (-n*k).is_nonpositive is False
assert u.is_nonpositive is None
assert (-u).is_nonpositive is True
assert (2*u).is_nonpositive is None
assert v.is_nonpositive is True
assert (-v).is_nonpositive is None
assert (2*v).is_nonpositive is True
assert (u*v).is_nonpositive is True
assert (k*u).is_nonpositive is True
assert (k*v).is_nonpositive is None
assert (n*u).is_nonpositive is None
assert (n*v).is_nonpositive is True
assert (v*k*u).is_nonpositive is None
assert (v*n*u).is_nonpositive is True
assert (-v*k*u).is_nonpositive is True
assert (-v*n*u).is_nonpositive is None
assert (17*v*k*u).is_nonpositive is None
assert (17*v*n*u).is_nonpositive is True
assert (k*v*n*u).is_nonpositive is None
assert (x*k).is_nonpositive is None
assert (u*v*n*x*k).is_nonpositive is None
assert k.is_nonnegative is False
assert (-k).is_nonnegative is True
assert (2*k).is_nonnegative is False
assert n.is_nonnegative is True
assert (-n).is_nonnegative is False
assert (2*n).is_nonnegative is True
assert (n*k).is_nonnegative is False
assert (2*n*k).is_nonnegative is False
assert (-n*k).is_nonnegative is True
assert u.is_nonnegative is True
assert (-u).is_nonnegative is None
assert (2*u).is_nonnegative is True
assert v.is_nonnegative is None
assert (-v).is_nonnegative is True
assert (2*v).is_nonnegative is None
assert (u*v).is_nonnegative is None
assert (k*u).is_nonnegative is None
assert (k*v).is_nonnegative is True
assert (n*u).is_nonnegative is True
assert (n*v).is_nonnegative is None
assert (v*k*u).is_nonnegative is True
assert (v*n*u).is_nonnegative is None
assert (-v*k*u).is_nonnegative is None
assert (-v*n*u).is_nonnegative is True
assert (17*v*k*u).is_nonnegative is True
assert (17*v*n*u).is_nonnegative is None
assert (k*v*n*u).is_nonnegative is True
assert (x*k).is_nonnegative is None
assert (u*v*n*x*k).is_nonnegative is None
def test_Add_is_negative_positive():
x = Symbol('x', real=True)
k = Symbol('k', negative=True)
n = Symbol('n', positive=True)
u = Symbol('u', nonnegative=True)
v = Symbol('v', nonpositive=True)
assert (k - 2).is_negative is True
assert (k + 17).is_negative is None
assert (-k - 5).is_negative is None
assert (-k + 123).is_negative is False
assert (k - n).is_negative is True
assert (k + n).is_negative is None
assert (-k - n).is_negative is None
assert (-k + n).is_negative is False
assert (k - n - 2).is_negative is True
assert (k + n + 17).is_negative is None
assert (-k - n - 5).is_negative is None
assert (-k + n + 123).is_negative is False
assert (-2*k + 123*n + 17).is_negative is False
assert (k + u).is_negative is None
assert (k + v).is_negative is True
assert (n + u).is_negative is False
assert (n + v).is_negative is None
assert (u - v).is_negative is False
assert (u + v).is_negative is None
assert (-u - v).is_negative is None
assert (-u + v).is_negative is None
assert (u - v + n + 2).is_negative is False
assert (u + v + n + 2).is_negative is None
assert (-u - v + n + 2).is_negative is None
assert (-u + v + n + 2).is_negative is None
assert (k + x).is_negative is None
assert (k + x - n).is_negative is None
assert (k - 2).is_positive is False
assert (k + 17).is_positive is None
assert (-k - 5).is_positive is None
assert (-k + 123).is_positive is True
assert (k - n).is_positive is False
assert (k + n).is_positive is None
assert (-k - n).is_positive is None
assert (-k + n).is_positive is True
assert (k - n - 2).is_positive is False
assert (k + n + 17).is_positive is None
assert (-k - n - 5).is_positive is None
assert (-k + n + 123).is_positive is True
assert (-2*k + 123*n + 17).is_positive is True
assert (k + u).is_positive is None
assert (k + v).is_positive is False
assert (n + u).is_positive is True
assert (n + v).is_positive is None
assert (u - v).is_positive is None
assert (u + v).is_positive is None
assert (-u - v).is_positive is None
assert (-u + v).is_positive is False
assert (u - v - n - 2).is_positive is None
assert (u + v - n - 2).is_positive is None
assert (-u - v - n - 2).is_positive is None
assert (-u + v - n - 2).is_positive is False
assert (n + x).is_positive is None
assert (n + x - k).is_positive is None
z = (-3 - sqrt(5) + (-sqrt(10)/2 - sqrt(2)/2)**2)
assert z.is_zero
z = sqrt(1 + sqrt(3)) + sqrt(3 + 3*sqrt(3)) - sqrt(10 + 6*sqrt(3))
assert z.is_zero
def test_Add_is_nonpositive_nonnegative():
x = Symbol('x', real=True)
k = Symbol('k', negative=True)
n = Symbol('n', positive=True)
u = Symbol('u', nonnegative=True)
v = Symbol('v', nonpositive=True)
assert (u - 2).is_nonpositive is None
assert (u + 17).is_nonpositive is False
assert (-u - 5).is_nonpositive is True
assert (-u + 123).is_nonpositive is None
assert (u - v).is_nonpositive is None
assert (u + v).is_nonpositive is None
assert (-u - v).is_nonpositive is None
assert (-u + v).is_nonpositive is True
assert (u - v - 2).is_nonpositive is None
assert (u + v + 17).is_nonpositive is None
assert (-u - v - 5).is_nonpositive is None
assert (-u + v - 123).is_nonpositive is True
assert (-2*u + 123*v - 17).is_nonpositive is True
assert (k + u).is_nonpositive is None
assert (k + v).is_nonpositive is True
assert (n + u).is_nonpositive is False
assert (n + v).is_nonpositive is None
assert (k - n).is_nonpositive is True
assert (k + n).is_nonpositive is None
assert (-k - n).is_nonpositive is None
assert (-k + n).is_nonpositive is False
assert (k - n + u + 2).is_nonpositive is None
assert (k + n + u + 2).is_nonpositive is None
assert (-k - n + u + 2).is_nonpositive is None
assert (-k + n + u + 2).is_nonpositive is False
assert (u + x).is_nonpositive is None
assert (v - x - n).is_nonpositive is None
assert (u - 2).is_nonnegative is None
assert (u + 17).is_nonnegative is True
assert (-u - 5).is_nonnegative is False
assert (-u + 123).is_nonnegative is None
assert (u - v).is_nonnegative is True
assert (u + v).is_nonnegative is None
assert (-u - v).is_nonnegative is None
assert (-u + v).is_nonnegative is None
assert (u - v + 2).is_nonnegative is True
assert (u + v + 17).is_nonnegative is None
assert (-u - v - 5).is_nonnegative is None
assert (-u + v - 123).is_nonnegative is False
assert (2*u - 123*v + 17).is_nonnegative is True
assert (k + u).is_nonnegative is None
assert (k + v).is_nonnegative is False
assert (n + u).is_nonnegative is True
assert (n + v).is_nonnegative is None
assert (k - n).is_nonnegative is False
assert (k + n).is_nonnegative is None
assert (-k - n).is_nonnegative is None
assert (-k + n).is_nonnegative is True
assert (k - n - u - 2).is_nonnegative is False
assert (k + n - u - 2).is_nonnegative is None
assert (-k - n - u - 2).is_nonnegative is None
assert (-k + n - u - 2).is_nonnegative is None
assert (u - x).is_nonnegative is None
assert (v + x + n).is_nonnegative is None
def test_Pow_is_integer():
x = Symbol('x')
k = Symbol('k', integer=True)
n = Symbol('n', integer=True, nonnegative=True)
m = Symbol('m', integer=True, positive=True)
assert (k**2).is_integer is True
assert (k**(-2)).is_integer is None
assert ((m + 1)**(-2)).is_integer is False
assert (m**(-1)).is_integer is None # issue 8580
assert (2**k).is_integer is None
assert (2**(-k)).is_integer is None
assert (2**n).is_integer is True
assert (2**(-n)).is_integer is None
assert (2**m).is_integer is True
assert (2**(-m)).is_integer is False
assert (x**2).is_integer is None
assert (2**x).is_integer is None
assert (k**n).is_integer is True
assert (k**(-n)).is_integer is None
assert (k**x).is_integer is None
assert (x**k).is_integer is None
assert (k**(n*m)).is_integer is True
assert (k**(-n*m)).is_integer is None
assert sqrt(3).is_integer is False
assert sqrt(.3).is_integer is False
assert Pow(3, 2, evaluate=False).is_integer is True
assert Pow(3, 0, evaluate=False).is_integer is True
assert Pow(3, -2, evaluate=False).is_integer is False
assert Pow(S.Half, 3, evaluate=False).is_integer is False
# decided by re-evaluating
assert Pow(3, S.Half, evaluate=False).is_integer is False
assert Pow(3, S.Half, evaluate=False).is_integer is False
assert Pow(4, S.Half, evaluate=False).is_integer is True
assert Pow(S.Half, -2, evaluate=False).is_integer is True
assert ((-1)**k).is_integer
x = Symbol('x', real=True, integer=False)
assert (x**2).is_integer is None # issue 8641
def test_Pow_is_real():
x = Symbol('x', real=True)
y = Symbol('y', real=True, positive=True)
assert (x**2).is_real is True
assert (x**3).is_real is True
assert (x**x).is_real is None
assert (y**x).is_real is True
assert (x**Rational(1, 3)).is_real is None
assert (y**Rational(1, 3)).is_real is True
assert sqrt(-1 - sqrt(2)).is_real is False
i = Symbol('i', imaginary=True)
assert (i**i).is_real is None
assert (I**i).is_real is True
assert ((-I)**i).is_real is True
assert (2**i).is_real is None # (2**(pi/log(2) * I)) is real, 2**I is not
assert (2**I).is_real is False
assert (2**-I).is_real is False
assert (i**2).is_real is True
assert (i**3).is_real is False
assert (i**x).is_real is None # could be (-I)**(2/3)
e = Symbol('e', even=True)
o = Symbol('o', odd=True)
k = Symbol('k', integer=True)
assert (i**e).is_real is True
assert (i**o).is_real is False
assert (i**k).is_real is None
assert (i**(4*k)).is_real is True
x = Symbol("x", nonnegative=True)
y = Symbol("y", nonnegative=True)
assert im(x**y).expand(complex=True) is S.Zero
assert (x**y).is_real is True
i = Symbol('i', imaginary=True)
assert (exp(i)**I).is_real is True
assert log(exp(i)).is_imaginary is None # i could be 2*pi*I
c = Symbol('c', complex=True)
assert log(c).is_real is None # c could be 0 or 2, too
assert log(exp(c)).is_real is None # log(0), log(E), ...
n = Symbol('n', negative=False)
assert log(n).is_real is None
n = Symbol('n', nonnegative=True)
assert log(n).is_real is None
assert sqrt(-I).is_real is False # issue 7843
def test_real_Pow():
k = Symbol('k', integer=True, nonzero=True)
assert (k**(I*pi/log(k))).is_real
def test_Pow_is_finite():
x = Symbol('x', real=True)
p = Symbol('p', positive=True)
n = Symbol('n', negative=True)
assert (x**2).is_finite is None # x could be oo
assert (x**x).is_finite is None # ditto
assert (p**x).is_finite is None # ditto
assert (n**x).is_finite is None # ditto
assert (1/S.Pi).is_finite
assert (sin(x)**2).is_finite is True
assert (sin(x)**x).is_finite is None
assert (sin(x)**exp(x)).is_finite is None
assert (1/sin(x)).is_finite is None # if zero, no, otherwise yes
assert (1/exp(x)).is_finite is None # x could be -oo
def test_Pow_is_even_odd():
x = Symbol('x')
k = Symbol('k', even=True)
n = Symbol('n', odd=True)
m = Symbol('m', integer=True, nonnegative=True)
p = Symbol('p', integer=True, positive=True)
assert ((-1)**n).is_odd
assert ((-1)**k).is_odd
assert ((-1)**(m - p)).is_odd
assert (k**2).is_even is True
assert (n**2).is_even is False
assert (2**k).is_even is None
assert (x**2).is_even is None
assert (k**m).is_even is None
assert (n**m).is_even is False
assert (k**p).is_even is True
assert (n**p).is_even is False
assert (m**k).is_even is None
assert (p**k).is_even is None
assert (m**n).is_even is None
assert (p**n).is_even is None
assert (k**x).is_even is None
assert (n**x).is_even is None
assert (k**2).is_odd is False
assert (n**2).is_odd is True
assert (3**k).is_odd is None
assert (k**m).is_odd is None
assert (n**m).is_odd is True
assert (k**p).is_odd is False
assert (n**p).is_odd is True
assert (m**k).is_odd is None
assert (p**k).is_odd is None
assert (m**n).is_odd is None
assert (p**n).is_odd is None
assert (k**x).is_odd is None
assert (n**x).is_odd is None
def test_Pow_is_negative_positive():
r = Symbol('r', real=True)
k = Symbol('k', integer=True, positive=True)
n = Symbol('n', even=True)
m = Symbol('m', odd=True)
x = Symbol('x')
assert (2**r).is_positive is True
assert ((-2)**r).is_positive is None
assert ((-2)**n).is_positive is True
assert ((-2)**m).is_positive is False
assert (k**2).is_positive is True
assert (k**(-2)).is_positive is True
assert (k**r).is_positive is True
assert ((-k)**r).is_positive is None
assert ((-k)**n).is_positive is True
assert ((-k)**m).is_positive is False
assert (2**r).is_negative is False
assert ((-2)**r).is_negative is None
assert ((-2)**n).is_negative is False
assert ((-2)**m).is_negative is True
assert (k**2).is_negative is False
assert (k**(-2)).is_negative is False
assert (k**r).is_negative is False
assert ((-k)**r).is_negative is None
assert ((-k)**n).is_negative is False
assert ((-k)**m).is_negative is True
assert (2**x).is_positive is None
assert (2**x).is_negative is None
def test_Pow_is_zero():
z = Symbol('z', zero=True)
e = z**2
assert e.is_zero
assert e.is_positive is False
assert e.is_negative is False
assert Pow(0, 0, evaluate=False).is_zero is False
assert Pow(0, 3, evaluate=False).is_zero
assert Pow(0, oo, evaluate=False).is_zero
assert Pow(0, -3, evaluate=False).is_zero is False
assert Pow(0, -oo, evaluate=False).is_zero is False
assert Pow(2, 2, evaluate=False).is_zero is False
a = Symbol('a', zero=False)
assert Pow(a, 3).is_zero is False # issue 7965
assert Pow(2, oo, evaluate=False).is_zero is False
assert Pow(2, -oo, evaluate=False).is_zero
assert Pow(S.Half, oo, evaluate=False).is_zero
assert Pow(S.Half, -oo, evaluate=False).is_zero is False
def test_Pow_is_nonpositive_nonnegative():
x = Symbol('x', real=True)
k = Symbol('k', integer=True, nonnegative=True)
l = Symbol('l', integer=True, positive=True)
n = Symbol('n', even=True)
m = Symbol('m', odd=True)
assert (x**(4*k)).is_nonnegative is True
assert (2**x).is_nonnegative is True
assert ((-2)**x).is_nonnegative is None
assert ((-2)**n).is_nonnegative is True
assert ((-2)**m).is_nonnegative is False
assert (k**2).is_nonnegative is True
assert (k**(-2)).is_nonnegative is None
assert (k**k).is_nonnegative is True
assert (k**x).is_nonnegative is None # NOTE (0**x).is_real = U
assert (l**x).is_nonnegative is True
assert (l**x).is_positive is True
assert ((-k)**x).is_nonnegative is None
assert ((-k)**m).is_nonnegative is None
assert (2**x).is_nonpositive is False
assert ((-2)**x).is_nonpositive is None
assert ((-2)**n).is_nonpositive is False
assert ((-2)**m).is_nonpositive is True
assert (k**2).is_nonpositive is None
assert (k**(-2)).is_nonpositive is None
assert (k**x).is_nonpositive is None
assert ((-k)**x).is_nonpositive is None
assert ((-k)**n).is_nonpositive is None
assert (x**2).is_nonnegative is True
i = symbols('i', imaginary=True)
assert (i**2).is_nonpositive is True
assert (i**4).is_nonpositive is False
assert (i**3).is_nonpositive is False
assert (I**i).is_nonnegative is True
assert (exp(I)**i).is_nonnegative is True
assert ((-k)**n).is_nonnegative is True
assert ((-k)**m).is_nonpositive is True
def test_Mul_is_imaginary_real():
r = Symbol('r', real=True)
p = Symbol('p', positive=True)
i = Symbol('i', imaginary=True)
ii = Symbol('ii', imaginary=True)
x = Symbol('x')
assert I.is_imaginary is True
assert I.is_real is False
assert (-I).is_imaginary is True
assert (-I).is_real is False
assert (3*I).is_imaginary is True
assert (3*I).is_real is False
assert (I*I).is_imaginary is False
assert (I*I).is_real is True
e = (p + p*I)
j = Symbol('j', integer=True, zero=False)
assert (e**j).is_real is None
assert (e**(2*j)).is_real is None
assert (e**j).is_imaginary is None
assert (e**(2*j)).is_imaginary is None
assert (e**-1).is_imaginary is False
assert (e**2).is_imaginary
assert (e**3).is_imaginary is False
assert (e**4).is_imaginary is False
assert (e**5).is_imaginary is False
assert (e**-1).is_real is False
assert (e**2).is_real is False
assert (e**3).is_real is False
assert (e**4).is_real
assert (e**5).is_real is False
assert (e**3).is_complex
assert (r*i).is_imaginary is None
assert (r*i).is_real is None
assert (x*i).is_imaginary is None
assert (x*i).is_real is None
assert (i*ii).is_imaginary is False
assert (i*ii).is_real is True
assert (r*i*ii).is_imaginary is False
assert (r*i*ii).is_real is True
# Github's issue 5874:
nr = Symbol('nr', real=False, complex=True) # e.g. I or 1 + I
a = Symbol('a', real=True, nonzero=True)
b = Symbol('b', real=True)
assert (i*nr).is_real is None
assert (a*nr).is_real is False
assert (b*nr).is_real is None
ni = Symbol('ni', imaginary=False, complex=True) # e.g. 2 or 1 + I
a = Symbol('a', real=True, nonzero=True)
b = Symbol('b', real=True)
assert (i*ni).is_real is False
assert (a*ni).is_real is None
assert (b*ni).is_real is None
def test_Mul_hermitian_antihermitian():
a = Symbol('a', hermitian=True, zero=False)
b = Symbol('b', hermitian=True)
c = Symbol('c', hermitian=False)
d = Symbol('d', antihermitian=True)
e1 = Mul(a, b, c, evaluate=False)
e2 = Mul(b, a, c, evaluate=False)
e3 = Mul(a, b, c, d, evaluate=False)
e4 = Mul(b, a, c, d, evaluate=False)
e5 = Mul(a, c, evaluate=False)
e6 = Mul(a, c, d, evaluate=False)
assert e1.is_hermitian is None
assert e2.is_hermitian is None
assert e1.is_antihermitian is None
assert e2.is_antihermitian is None
assert e3.is_antihermitian is None
assert e4.is_antihermitian is None
assert e5.is_antihermitian is None
assert e6.is_antihermitian is None
def test_Add_is_comparable():
assert (x + y).is_comparable is False
assert (x + 1).is_comparable is False
assert (Rational(1, 3) - sqrt(8)).is_comparable is True
def test_Mul_is_comparable():
assert (x*y).is_comparable is False
assert (x*2).is_comparable is False
assert (sqrt(2)*Rational(1, 3)).is_comparable is True
def test_Pow_is_comparable():
assert (x**y).is_comparable is False
assert (x**2).is_comparable is False
assert (sqrt(Rational(1, 3))).is_comparable is True
def test_Add_is_positive_2():
e = Rational(1, 3) - sqrt(8)
assert e.is_positive is False
assert e.is_negative is True
e = pi - 1
assert e.is_positive is True
assert e.is_negative is False
def test_Add_is_irrational():
i = Symbol('i', irrational=True)
assert i.is_irrational is True
assert i.is_rational is False
assert (i + 1).is_irrational is True
assert (i + 1).is_rational is False
@XFAIL
def test_issue_3531():
class MightyNumeric(tuple):
def __rdiv__(self, other):
return "something"
def __rtruediv__(self, other):
return "something"
assert sympify(1)/MightyNumeric((1, 2)) == "something"
def test_issue_3531b():
class Foo:
def __init__(self):
self.field = 1.0
def __mul__(self, other):
self.field = self.field * other
def __rmul__(self, other):
self.field = other * self.field
f = Foo()
x = Symbol("x")
assert f*x == x*f
def test_bug3():
a = Symbol("a")
b = Symbol("b", positive=True)
e = 2*a + b
f = b + 2*a
assert e == f
def test_suppressed_evaluation():
a = Add(0, 3, 2, evaluate=False)
b = Mul(1, 3, 2, evaluate=False)
c = Pow(3, 2, evaluate=False)
assert a != 6
assert a.func is Add
assert a.args == (3, 2)
assert b != 6
assert b.func is Mul
assert b.args == (3, 2)
assert c != 9
assert c.func is Pow
assert c.args == (3, 2)
def test_Add_as_coeff_mul():
# issue 5524. These should all be (1, self)
assert (x + 1).as_coeff_mul() == (1, (x + 1,))
assert (x + 2).as_coeff_mul() == (1, (x + 2,))
assert (x + 3).as_coeff_mul() == (1, (x + 3,))
assert (x - 1).as_coeff_mul() == (1, (x - 1,))
assert (x - 2).as_coeff_mul() == (1, (x - 2,))
assert (x - 3).as_coeff_mul() == (1, (x - 3,))
n = Symbol('n', integer=True)
assert (n + 1).as_coeff_mul() == (1, (n + 1,))
assert (n + 2).as_coeff_mul() == (1, (n + 2,))
assert (n + 3).as_coeff_mul() == (1, (n + 3,))
assert (n - 1).as_coeff_mul() == (1, (n - 1,))
assert (n - 2).as_coeff_mul() == (1, (n - 2,))
assert (n - 3).as_coeff_mul() == (1, (n - 3,))
def test_Pow_as_coeff_mul_doesnt_expand():
assert exp(x + y).as_coeff_mul() == (1, (exp(x + y),))
assert exp(x + exp(x + y)) != exp(x + exp(x)*exp(y))
def test_issue_3514():
assert sqrt(S.Half) * sqrt(6) == 2 * sqrt(3)/2
assert S(1)/2*sqrt(6)*sqrt(2) == sqrt(3)
assert sqrt(6)/2*sqrt(2) == sqrt(3)
assert sqrt(6)*sqrt(2)/2 == sqrt(3)
def test_make_args():
assert Add.make_args(x) == (x,)
assert Mul.make_args(x) == (x,)
assert Add.make_args(x*y*z) == (x*y*z,)
assert Mul.make_args(x*y*z) == (x*y*z).args
assert Add.make_args(x + y + z) == (x + y + z).args
assert Mul.make_args(x + y + z) == (x + y + z,)
assert Add.make_args((x + y)**z) == ((x + y)**z,)
assert Mul.make_args((x + y)**z) == ((x + y)**z,)
def test_issue_5126():
assert (-2)**x*(-3)**x != 6**x
i = Symbol('i', integer=1)
assert (-2)**i*(-3)**i == 6**i
def test_Rational_as_content_primitive():
c, p = S(1), S(0)
assert (c*p).as_content_primitive() == (c, p)
c, p = S(1)/2, S(1)
assert (c*p).as_content_primitive() == (c, p)
def test_Add_as_content_primitive():
assert (x + 2).as_content_primitive() == (1, x + 2)
assert (3*x + 2).as_content_primitive() == (1, 3*x + 2)
assert (3*x + 3).as_content_primitive() == (3, x + 1)
assert (3*x + 6).as_content_primitive() == (3, x + 2)
assert (3*x + 2*y).as_content_primitive() == (1, 3*x + 2*y)
assert (3*x + 3*y).as_content_primitive() == (3, x + y)
assert (3*x + 6*y).as_content_primitive() == (3, x + 2*y)
assert (3/x + 2*x*y*z**2).as_content_primitive() == (1, 3/x + 2*x*y*z**2)
assert (3/x + 3*x*y*z**2).as_content_primitive() == (3, 1/x + x*y*z**2)
assert (3/x + 6*x*y*z**2).as_content_primitive() == (3, 1/x + 2*x*y*z**2)
assert (2*x/3 + 4*y/9).as_content_primitive() == \
(Rational(2, 9), 3*x + 2*y)
assert (2*x/3 + 2.5*y).as_content_primitive() == \
(Rational(1, 3), 2*x + 7.5*y)
# the coefficient may sort to a position other than 0
p = 3 + x + y
assert (2*p).expand().as_content_primitive() == (2, p)
assert (2.0*p).expand().as_content_primitive() == (1, 2.*p)
p *= -1
assert (2*p).expand().as_content_primitive() == (2, p)
def test_Mul_as_content_primitive():
assert (2*x).as_content_primitive() == (2, x)
assert (x*(2 + 2*x)).as_content_primitive() == (2, x*(1 + x))
assert (x*(2 + 2*y)*(3*x + 3)**2).as_content_primitive() == \
(18, x*(1 + y)*(x + 1)**2)
assert ((2 + 2*x)**2*(3 + 6*x) + S.Half).as_content_primitive() == \
(S.Half, 24*(x + 1)**2*(2*x + 1) + 1)
def test_Pow_as_content_primitive():
assert (x**y).as_content_primitive() == (1, x**y)
assert ((2*x + 2)**y).as_content_primitive() == \
(1, (Mul(2, (x + 1), evaluate=False))**y)
assert ((2*x + 2)**3).as_content_primitive() == (8, (x + 1)**3)
def test_issue_5460():
u = Mul(2, (1 + x), evaluate=False)
assert (2 + u).args == (2, u)
def test_product_irrational():
from sympy import I, pi
assert (I*pi).is_irrational is False
# The following used to be deduced from the above bug:
assert (I*pi).is_positive is False
def test_issue_5919():
assert (x/(y*(1 + y))).expand() == x/(y**2 + y)
def test_Mod():
assert Mod(x, 1).func is Mod
assert pi % pi == S.Zero
assert Mod(5, 3) == 2
assert Mod(-5, 3) == 1
assert Mod(5, -3) == -1
assert Mod(-5, -3) == -2
assert type(Mod(3.2, 2, evaluate=False)) == Mod
assert 5 % x == Mod(5, x)
assert x % 5 == Mod(x, 5)
assert x % y == Mod(x, y)
assert (x % y).subs({x: 5, y: 3}) == 2
assert Mod(nan, 1) == nan
assert Mod(1, nan) == nan
assert Mod(nan, nan) == nan
Mod(0, x) == 0
with raises(ZeroDivisionError):
Mod(x, 0)
k = Symbol('k', integer=True)
m = Symbol('m', integer=True, positive=True)
assert (x**m % x).func is Mod
assert (k**(-m) % k).func is Mod
assert k**m % k == 0
assert (-2*k)**m % k == 0
# Float handling
point3 = Float(3.3) % 1
assert (x - 3.3) % 1 == Mod(1.*x + 1 - point3, 1)
assert Mod(-3.3, 1) == 1 - point3
assert Mod(0.7, 1) == Float(0.7)
e = Mod(1.3, 1)
assert comp(e, .3) and e.is_Float
e = Mod(1.3, .7)
assert comp(e, .6) and e.is_Float
e = Mod(1.3, Rational(7, 10))
assert comp(e, .6) and e.is_Float
e = Mod(Rational(13, 10), 0.7)
assert comp(e, .6) and e.is_Float
e = Mod(Rational(13, 10), Rational(7, 10))
assert comp(e, .6) and e.is_Rational
# check that sign is right
r2 = sqrt(2)
r3 = sqrt(3)
for i in [-r3, -r2, r2, r3]:
for j in [-r3, -r2, r2, r3]:
assert verify_numerically(i % j, i.n() % j.n())
for _x in range(4):
for _y in range(9):
reps = [(x, _x), (y, _y)]
assert Mod(3*x + y, 9).subs(reps) == (3*_x + _y) % 9
# denesting
t = Symbol('t', real=True)
assert Mod(Mod(x, t), t) == Mod(x, t)
assert Mod(-Mod(x, t), t) == Mod(-x, t)
assert Mod(Mod(x, 2*t), t) == Mod(x, t)
assert Mod(-Mod(x, 2*t), t) == Mod(-x, t)
assert Mod(Mod(x, t), 2*t) == Mod(x, t)
assert Mod(-Mod(x, t), -2*t) == -Mod(x, t)
for i in [-4, -2, 2, 4]:
for j in [-4, -2, 2, 4]:
for k in range(4):
assert Mod(Mod(x, i), j).subs({x: k}) == (k % i) % j
assert Mod(-Mod(x, i), j).subs({x: k}) == -(k % i) % j
# known difference
assert Mod(5*sqrt(2), sqrt(5)) == 5*sqrt(2) - 3*sqrt(5)
p = symbols('p', positive=True)
assert Mod(2, p + 3) == 2
assert Mod(-2, p + 3) == p + 1
assert Mod(2, -p - 3) == -p - 1
assert Mod(-2, -p - 3) == -2
assert Mod(p + 5, p + 3) == 2
assert Mod(-p - 5, p + 3) == p + 1
assert Mod(p + 5, -p - 3) == -p - 1
assert Mod(-p - 5, -p - 3) == -2
assert Mod(p + 1, p - 1).func is Mod
# handling sums
assert (x + 3) % 1 == Mod(x, 1)
assert (x + 3.0) % 1 == Mod(1.*x, 1)
assert (x - S(33)/10) % 1 == Mod(x + S(7)/10, 1)
a = Mod(.6*x + y, .3*y)
b = Mod(0.1*y + 0.6*x, 0.3*y)
# Test that a, b are equal, with 1e-14 accuracy in coefficients
eps = 1e-14
assert abs((a.args[0] - b.args[0]).subs({x: 1, y: 1})) < eps
assert abs((a.args[1] - b.args[1]).subs({x: 1, y: 1})) < eps
assert (x + 1) % x == 1 % x
assert (x + y) % x == y % x
assert (x + y + 2) % x == (y + 2) % x
assert (a + 3*x + 1) % (2*x) == Mod(a + x + 1, 2*x)
assert (12*x + 18*y) % (3*x) == 3*Mod(6*y, x)
# gcd extraction
assert (-3*x) % (-2*y) == -Mod(3*x, 2*y)
assert (.6*pi) % (.3*x*pi) == 0.3*pi*Mod(2, x)
assert (.6*pi) % (.31*x*pi) == pi*Mod(0.6, 0.31*x)
assert (6*pi) % (.3*x*pi) == 0.3*pi*Mod(20, x)
assert (6*pi) % (.31*x*pi) == pi*Mod(6, 0.31*x)
assert (6*pi) % (.42*x*pi) == pi*Mod(6, 0.42*x)
assert (12*x) % (2*y) == 2*Mod(6*x, y)
assert (12*x) % (3*5*y) == 3*Mod(4*x, 5*y)
assert (12*x) % (15*x*y) == 3*x*Mod(4, 5*y)
assert (-2*pi) % (3*pi) == pi
assert (2*x + 2) % (x + 1) == 0
assert (x*(x + 1)) % (x + 1) == (x + 1)*Mod(x, 1)
assert Mod(5.0*x, 0.1*y) == 0.1*Mod(50*x, y)
i = Symbol('i', integer=True)
assert (3*i*x) % (2*i*y) == i*Mod(3*x, 2*y)
assert Mod(4*i, 4) == 0
# issue 8677
n = Symbol('n', integer=True, positive=True)
assert factorial(n) % n == 0
assert factorial(n + 2) % n == 0
assert (factorial(n + 4) % (n + 5)).func is Mod
# modular exponentiation
assert Mod(Pow(4, 13, evaluate=False), 497) == Mod(Pow(4, 13), 497)
assert Mod(Pow(2, 10000000000, evaluate=False), 3) == 1
assert Mod(Pow(32131231232, 9**10**6, evaluate=False),10**12) == pow(32131231232,9**10**6,10**12)
assert Mod(Pow(33284959323, 123**999, evaluate=False),11**13) == pow(33284959323,123**999,11**13)
assert Mod(Pow(78789849597, 333**555, evaluate=False),12**9) == pow(78789849597,333**555,12**9)
# Wilson's theorem
factorial(18042, evaluate=False) % 18043 == 18042
p = Symbol('n', prime=True)
factorial(p - 1) % p == p - 1
factorial(p - 1) % -p == -1
(factorial(3, evaluate=False) % 4).doit() == 2
n = Symbol('n', composite=True, odd=True)
factorial(n - 1) % n == 0
# symbolic with known parity
n = Symbol('n', even=True)
assert Mod(n, 2) == 0
n = Symbol('n', odd=True)
assert Mod(n, 2) == 1
# issue 10963
assert (x**6000%400).args[1] == 400
#issue 13543
assert Mod(Mod(x + 1, 2) + 1 , 2) == Mod(x,2)
assert Mod(Mod(x + 2, 4)*(x + 4), 4) == Mod(x*(x + 2), 4)
assert Mod(Mod(x + 2, 4)*4, 4) == 0
# issue 15493
i, j = symbols('i j', integer=True, positive=True)
assert Mod(3*i, 2) == Mod(i, 2)
assert Mod(8*i/j, 4) == 4*Mod(2*i/j, 1)
assert Mod(8*i, 4) == 0
def test_Mod_is_integer():
p = Symbol('p', integer=True)
q1 = Symbol('q1', integer=True)
q2 = Symbol('q2', integer=True, nonzero=True)
assert Mod(x, y).is_integer is None
assert Mod(p, q1).is_integer is None
assert Mod(x, q2).is_integer is None
assert Mod(p, q2).is_integer
def test_Mod_is_nonposneg():
n = Symbol('n', integer=True)
k = Symbol('k', integer=True, positive=True)
assert (n%3).is_nonnegative
assert Mod(n, -3).is_nonpositive
assert Mod(n, k).is_nonnegative
assert Mod(n, -k).is_nonpositive
assert Mod(k, n).is_nonnegative is None
def test_issue_6001():
A = Symbol("A", commutative=False)
eq = A + A**2
# it doesn't matter whether it's True or False; they should
# just all be the same
assert (
eq.is_commutative ==
(eq + 1).is_commutative ==
(A + 1).is_commutative)
B = Symbol("B", commutative=False)
# Although commutative terms could cancel we return True
# meaning "there are non-commutative symbols; aftersubstitution
# that definition can change, e.g. (A*B).subs(B,A**-1) -> 1
assert (sqrt(2)*A).is_commutative is False
assert (sqrt(2)*A*B).is_commutative is False
def test_polar():
from sympy import polar_lift
p = Symbol('p', polar=True)
x = Symbol('x')
assert p.is_polar
assert x.is_polar is None
assert S(1).is_polar is None
assert (p**x).is_polar is True
assert (x**p).is_polar is None
assert ((2*p)**x).is_polar is True
assert (2*p).is_polar is True
assert (-2*p).is_polar is not True
assert (polar_lift(-2)*p).is_polar is True
q = Symbol('q', polar=True)
assert (p*q)**2 == p**2 * q**2
assert (2*q)**2 == 4 * q**2
assert ((p*q)**x).expand() == p**x * q**x
def test_issue_6040():
a, b = Pow(1, 2, evaluate=False), S.One
assert a != b
assert b != a
assert not (a == b)
assert not (b == a)
def test_issue_6082():
# Comparison is symmetric
assert Basic.compare(Max(x, 1), Max(x, 2)) == \
- Basic.compare(Max(x, 2), Max(x, 1))
# Equal expressions compare equal
assert Basic.compare(Max(x, 1), Max(x, 1)) == 0
# Basic subtypes (such as Max) compare different than standard types
assert Basic.compare(Max(1, x), frozenset((1, x))) != 0
def test_issue_6077():
assert x**2.0/x == x**1.0
assert x/x**2.0 == x**-1.0
assert x*x**2.0 == x**3.0
assert x**1.5*x**2.5 == x**4.0
assert 2**(2.0*x)/2**x == 2**(1.0*x)
assert 2**x/2**(2.0*x) == 2**(-1.0*x)
assert 2**x*2**(2.0*x) == 2**(3.0*x)
assert 2**(1.5*x)*2**(2.5*x) == 2**(4.0*x)
def test_mul_flatten_oo():
p = symbols('p', positive=True)
n, m = symbols('n,m', negative=True)
x_im = symbols('x_im', imaginary=True)
assert n*oo == -oo
assert n*m*oo == oo
assert p*oo == oo
assert x_im*oo != I*oo # i could be +/- 3*I -> +/-oo
def test_add_flatten():
# see https://github.com/sympy/sympy/issues/2633#issuecomment-29545524
a = oo + I*oo
b = oo - I*oo
assert a + b == nan
assert a - b == nan
assert (1/a).simplify() == (1/b).simplify() == 0
a = Pow(2, 3, evaluate=False)
assert a + a == 16
def test_issue_5160_6087_6089_6090():
# issue 6087
assert ((-2*x*y**y)**3.2).n(2) == (2**3.2*(-x*y**y)**3.2).n(2)
# issue 6089
A, B, C = symbols('A,B,C', commutative=False)
assert (2.*B*C)**3 == 8.0*(B*C)**3
assert (-2.*B*C)**3 == -8.0*(B*C)**3
assert (-2*B*C)**2 == 4*(B*C)**2
# issue 5160
assert sqrt(-1.0*x) == 1.0*sqrt(-x)
assert sqrt(1.0*x) == 1.0*sqrt(x)
# issue 6090
assert (-2*x*y*A*B)**2 == 4*x**2*y**2*(A*B)**2
def test_float_int():
assert int(float(sqrt(10))) == int(sqrt(10))
assert int(pi**1000) % 10 == 2
assert int(Float('1.123456789012345678901234567890e20', '')) == \
long(112345678901234567890)
assert int(Float('1.123456789012345678901234567890e25', '')) == \
long(11234567890123456789012345)
# decimal forces float so it's not an exact integer ending in 000000
assert int(Float('1.123456789012345678901234567890e35', '')) == \
112345678901234567890123456789000192
assert int(Float('123456789012345678901234567890e5', '')) == \
12345678901234567890123456789000000
assert Integer(Float('1.123456789012345678901234567890e20', '')) == \
112345678901234567890
assert Integer(Float('1.123456789012345678901234567890e25', '')) == \
11234567890123456789012345
# decimal forces float so it's not an exact integer ending in 000000
assert Integer(Float('1.123456789012345678901234567890e35', '')) == \
112345678901234567890123456789000192
assert Integer(Float('123456789012345678901234567890e5', '')) == \
12345678901234567890123456789000000
assert same_and_same_prec(Float('123000e-2',''), Float('1230.00', ''))
assert same_and_same_prec(Float('123000e2',''), Float('12300000', ''))
assert int(1 + Rational('.9999999999999999999999999')) == 1
assert int(pi/1e20) == 0
assert int(1 + pi/1e20) == 1
assert int(Add(1.2, -2, evaluate=False)) == int(1.2 - 2)
assert int(Add(1.2, +2, evaluate=False)) == int(1.2 + 2)
assert int(Add(1 + Float('.99999999999999999', ''), evaluate=False)) == 1
raises(TypeError, lambda: float(x))
raises(TypeError, lambda: float(sqrt(-1)))
assert int(12345678901234567890 + cos(1)**2 + sin(1)**2) == \
12345678901234567891
def test_issue_6611a():
assert Mul.flatten([3**Rational(1, 3),
Pow(-Rational(1, 9), Rational(2, 3), evaluate=False)]) == \
([Rational(1, 3), (-1)**Rational(2, 3)], [], None)
def test_denest_add_mul():
# when working with evaluated expressions make sure they denest
eq = x + 1
eq = Add(eq, 2, evaluate=False)
eq = Add(eq, 2, evaluate=False)
assert Add(*eq.args) == x + 5
eq = x*2
eq = Mul(eq, 2, evaluate=False)
eq = Mul(eq, 2, evaluate=False)
assert Mul(*eq.args) == 8*x
# but don't let them denest unecessarily
eq = Mul(-2, x - 2, evaluate=False)
assert 2*eq == Mul(-4, x - 2, evaluate=False)
assert -eq == Mul(2, x - 2, evaluate=False)
def test_mul_coeff():
# It is important that all Numbers be removed from the seq;
# This can be tricky when powers combine to produce those numbers
p = exp(I*pi/3)
assert p**2*x*p*y*p*x*p**2 == x**2*y
def test_mul_zero_detection():
nz = Dummy(real=True, zero=False, finite=True)
r = Dummy(real=True)
c = Dummy(real=False, complex=True, finite=True)
c2 = Dummy(real=False, complex=True, finite=True)
i = Dummy(imaginary=True, finite=True)
e = nz*r*c
assert e.is_imaginary is None
assert e.is_real is None
e = nz*c
assert e.is_imaginary is None
assert e.is_real is False
e = nz*i*c
assert e.is_imaginary is False
assert e.is_real is None
# check for more than one complex; it is important to use
# uniquely named Symbols to ensure that two factors appear
# e.g. if the symbols have the same name they just become
# a single factor, a power.
e = nz*i*c*c2
assert e.is_imaginary is None
assert e.is_real is None
# _eval_is_real and _eval_is_zero both employ trapping of the
# zero value so args should be tested in both directions and
# TO AVOID GETTING THE CACHED RESULT, Dummy MUST BE USED
# real is unknonwn
def test(z, b, e):
if z.is_zero and b.is_finite:
assert e.is_real and e.is_zero
else:
assert e.is_real is None
if b.is_finite:
if z.is_zero:
assert e.is_zero
else:
assert e.is_zero is None
elif b.is_finite is False:
if z.is_zero is None:
assert e.is_zero is None
else:
assert e.is_zero is False
for iz, ib in cartes(*[[True, False, None]]*2):
z = Dummy('z', nonzero=iz)
b = Dummy('f', finite=ib)
e = Mul(z, b, evaluate=False)
test(z, b, e)
z = Dummy('nz', nonzero=iz)
b = Dummy('f', finite=ib)
e = Mul(b, z, evaluate=False)
test(z, b, e)
# real is True
def test(z, b, e):
if z.is_zero and not b.is_finite:
assert e.is_real is None
else:
assert e.is_real
for iz, ib in cartes(*[[True, False, None]]*2):
z = Dummy('z', nonzero=iz, real=True)
b = Dummy('b', finite=ib, real=True)
e = Mul(z, b, evaluate=False)
test(z, b, e)
z = Dummy('z', nonzero=iz, real=True)
b = Dummy('b', finite=ib, real=True)
e = Mul(b, z, evaluate=False)
test(z, b, e)
def test_Mul_with_zero_infinite():
zer = Dummy(zero=True)
inf = Dummy(finite=False)
e = Mul(zer, inf, evaluate=False)
assert e.is_positive is None
assert e.is_hermitian is None
e = Mul(inf, zer, evaluate=False)
assert e.is_positive is None
assert e.is_hermitian is None
def test_Mul_does_not_cancel_infinities():
a, b = symbols('a b')
assert ((zoo + 3*a)/(3*a + zoo)) is nan
assert ((b - oo)/(b - oo)) is nan
# issue 13904
expr = (1/(a+b) + 1/(a-b))/(1/(a+b) - 1/(a-b))
assert expr.subs(b, a) is nan
def test_Mul_does_not_distribute_infinity():
a, b = symbols('a b')
assert ((1 + I)*oo).is_Mul
assert ((a + b)*(-oo)).is_Mul
assert ((a + 1)*zoo).is_Mul
assert ((1 + I)*oo).is_finite is False
z = (1 + I)*oo
assert ((1 - I)*z).expand() is oo
def test_issue_8247_8354():
from sympy import tan
z = sqrt(1 + sqrt(3)) + sqrt(3 + 3*sqrt(3)) - sqrt(10 + 6*sqrt(3))
assert z.is_positive is False # it's 0
z = S('''-2**(1/3)*(3*sqrt(93) + 29)**2 - 4*(3*sqrt(93) + 29)**(4/3) +
12*sqrt(93)*(3*sqrt(93) + 29)**(1/3) + 116*(3*sqrt(93) + 29)**(1/3) +
174*2**(1/3)*sqrt(93) + 1678*2**(1/3)''')
assert z.is_positive is False # it's 0
z = 2*(-3*tan(19*pi/90) + sqrt(3))*cos(11*pi/90)*cos(19*pi/90) - \
sqrt(3)*(-3 + 4*cos(19*pi/90)**2)
assert z.is_positive is not True # it's zero and it shouldn't hang
z = S('''9*(3*sqrt(93) + 29)**(2/3)*((3*sqrt(93) +
29)**(1/3)*(-2**(2/3)*(3*sqrt(93) + 29)**(1/3) - 2) - 2*2**(1/3))**3 +
72*(3*sqrt(93) + 29)**(2/3)*(81*sqrt(93) + 783) + (162*sqrt(93) +
1566)*((3*sqrt(93) + 29)**(1/3)*(-2**(2/3)*(3*sqrt(93) + 29)**(1/3) -
2) - 2*2**(1/3))**2''')
assert z.is_positive is False # it's 0 (and a single _mexpand isn't enough)
def test_Add_is_zero():
x, y = symbols('x y', zero=True)
assert (x + y).is_zero
def test_issue_14392():
assert (sin(zoo)**2).as_real_imag() == (nan, nan)
def test_divmod():
assert divmod(x, y) == (x//y, x % y)
assert divmod(x, 3) == (x//3, x % 3)
assert divmod(3, x) == (3//x, 3 % x)
|
1dd40b3351bbfa62945303b9c1bea625b8031f38a27b964f2dc603ec0d02b6d7
|
"""Tests that the IPython printing module is properly loaded. """
from sympy.interactive.session import init_ipython_session
from sympy.external import import_module
from sympy.utilities.pytest import raises
# run_cell was added in IPython 0.11
ipython = import_module("IPython", min_module_version="0.11")
# disable tests if ipython is not present
if not ipython:
disabled = True
def test_ipythonprinting():
# Initialize and setup IPython session
app = init_ipython_session()
app.run_cell("ip = get_ipython()")
app.run_cell("inst = ip.instance()")
app.run_cell("format = inst.display_formatter.format")
app.run_cell("from sympy import Symbol")
# Printing without printing extension
app.run_cell("a = format(Symbol('pi'))")
app.run_cell("a2 = format(Symbol('pi')**2)")
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
assert app.user_ns['a']['text/plain'] == "pi"
assert app.user_ns['a2']['text/plain'] == "pi**2"
else:
assert app.user_ns['a'][0]['text/plain'] == "pi"
assert app.user_ns['a2'][0]['text/plain'] == "pi**2"
# Load printing extension
app.run_cell("from sympy import init_printing")
app.run_cell("init_printing()")
# Printing with printing extension
app.run_cell("a = format(Symbol('pi'))")
app.run_cell("a2 = format(Symbol('pi')**2)")
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
assert app.user_ns['a']['text/plain'] in (u'\N{GREEK SMALL LETTER PI}', 'pi')
assert app.user_ns['a2']['text/plain'] in (u' 2\n\N{GREEK SMALL LETTER PI} ', ' 2\npi ')
else:
assert app.user_ns['a'][0]['text/plain'] in (u'\N{GREEK SMALL LETTER PI}', 'pi')
assert app.user_ns['a2'][0]['text/plain'] in (u' 2\n\N{GREEK SMALL LETTER PI} ', ' 2\npi ')
def test_print_builtin_option():
# Initialize and setup IPython session
app = init_ipython_session()
app.run_cell("ip = get_ipython()")
app.run_cell("inst = ip.instance()")
app.run_cell("format = inst.display_formatter.format")
app.run_cell("from sympy import Symbol")
app.run_cell("from sympy import init_printing")
app.run_cell("a = format({Symbol('pi'): 3.14, Symbol('n_i'): 3})")
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
text = app.user_ns['a']['text/plain']
raises(KeyError, lambda: app.user_ns['a']['text/latex'])
else:
text = app.user_ns['a'][0]['text/plain']
raises(KeyError, lambda: app.user_ns['a'][0]['text/latex'])
# Note : Unicode of Python2 is equivalent to str in Python3. In Python 3 we have one
# text type: str which holds Unicode data and two byte types bytes and bytearray.
# XXX: How can we make this ignore the terminal width? This test fails if
# the terminal is too narrow.
assert text in ("{pi: 3.14, n_i: 3}",
u'{n\N{LATIN SUBSCRIPT SMALL LETTER I}: 3, \N{GREEK SMALL LETTER PI}: 3.14}',
"{n_i: 3, pi: 3.14}",
u'{\N{GREEK SMALL LETTER PI}: 3.14, n\N{LATIN SUBSCRIPT SMALL LETTER I}: 3}')
# If we enable the default printing, then the dictionary's should render
# as a LaTeX version of the whole dict: ${\pi: 3.14, n_i: 3}$
app.run_cell("inst.display_formatter.formatters['text/latex'].enabled = True")
app.run_cell("init_printing(use_latex=True)")
app.run_cell("a = format({Symbol('pi'): 3.14, Symbol('n_i'): 3})")
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
text = app.user_ns['a']['text/plain']
latex = app.user_ns['a']['text/latex']
else:
text = app.user_ns['a'][0]['text/plain']
latex = app.user_ns['a'][0]['text/latex']
assert text in ("{pi: 3.14, n_i: 3}",
u'{n\N{LATIN SUBSCRIPT SMALL LETTER I}: 3, \N{GREEK SMALL LETTER PI}: 3.14}',
"{n_i: 3, pi: 3.14}",
u'{\N{GREEK SMALL LETTER PI}: 3.14, n\N{LATIN SUBSCRIPT SMALL LETTER I}: 3}')
assert latex == r'$\displaystyle \left \{ n_{i} : 3, \quad \pi : 3.14\right \}$'
app.run_cell("inst.display_formatter.formatters['text/latex'].enabled = True")
app.run_cell("init_printing(use_latex=True, print_builtin=False)")
app.run_cell("a = format({Symbol('pi'): 3.14, Symbol('n_i'): 3})")
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
text = app.user_ns['a']['text/plain']
raises(KeyError, lambda: app.user_ns['a']['text/latex'])
else:
text = app.user_ns['a'][0]['text/plain']
raises(KeyError, lambda: app.user_ns['a'][0]['text/latex'])
# Note : Unicode of Python2 is equivalent to str in Python3. In Python 3 we have one
# text type: str which holds Unicode data and two byte types bytes and bytearray.
# Python 3.3.3 + IPython 0.13.2 gives: '{n_i: 3, pi: 3.14}'
# Python 3.3.3 + IPython 1.1.0 gives: '{n_i: 3, pi: 3.14}'
# Python 2.7.5 + IPython 1.1.0 gives: '{pi: 3.14, n_i: 3}'
assert text in ("{pi: 3.14, n_i: 3}", "{n_i: 3, pi: 3.14}")
def test_builtin_containers():
# Initialize and setup IPython session
app = init_ipython_session()
app.run_cell("ip = get_ipython()")
app.run_cell("inst = ip.instance()")
app.run_cell("format = inst.display_formatter.format")
app.run_cell("inst.display_formatter.formatters['text/latex'].enabled = True")
app.run_cell("from sympy import init_printing, Matrix")
app.run_cell('init_printing(use_latex=True, use_unicode=False)')
# Make sure containers that shouldn't pretty print don't.
app.run_cell('a = format((True, False))')
app.run_cell('import sys')
app.run_cell('b = format(sys.flags)')
app.run_cell('c = format((Matrix([1, 2]),))')
# Deal with API change starting at IPython 1.0
if int(ipython.__version__.split(".")[0]) < 1:
assert app.user_ns['a']['text/plain'] == '(True, False)'
assert 'text/latex' not in app.user_ns['a']
assert app.user_ns['b']['text/plain'][:10] == 'sys.flags('
assert 'text/latex' not in app.user_ns['b']
assert app.user_ns['c']['text/plain'] == \
"""\
[1] \n\
([ ],)
[2] \
"""
assert app.user_ns['c']['text/latex'] == '$\\displaystyle \\left ( \\left[\\begin{matrix}1\\\\2\\end{matrix}\\right]\\right )$'
else:
assert app.user_ns['a'][0]['text/plain'] == '(True, False)'
assert 'text/latex' not in app.user_ns['a'][0]
assert app.user_ns['b'][0]['text/plain'][:10] == 'sys.flags('
assert 'text/latex' not in app.user_ns['b'][0]
assert app.user_ns['c'][0]['text/plain'] == \
"""\
[1] \n\
([ ],)
[2] \
"""
assert app.user_ns['c'][0]['text/latex'] == '$\\displaystyle \\left ( \\left[\\begin{matrix}1\\\\2\\end{matrix}\\right]\\right )$'
def test_matplotlib_bad_latex():
# Initialize and setup IPython session
app = init_ipython_session()
app.run_cell("import IPython")
app.run_cell("ip = get_ipython()")
app.run_cell("inst = ip.instance()")
app.run_cell("format = inst.display_formatter.format")
app.run_cell("from sympy import init_printing, Matrix")
app.run_cell("init_printing(use_latex='matplotlib')")
# The png formatter is not enabled by default in this context
app.run_cell("inst.display_formatter.formatters['image/png'].enabled = True")
# Make sure no warnings are raised by IPython
app.run_cell("import warnings")
# IPython.core.formatters.FormatterWarning was introduced in IPython 2.0
if int(ipython.__version__.split(".")[0]) < 2:
app.run_cell("warnings.simplefilter('error')")
else:
app.run_cell("warnings.simplefilter('error', IPython.core.formatters.FormatterWarning)")
# This should not raise an exception
app.run_cell("a = format(Matrix([1, 2, 3]))")
# issue 9799
app.run_cell("from sympy import Piecewise, Symbol, Eq")
app.run_cell("x = Symbol('x'); pw = format(Piecewise((1, Eq(x, 0)), (0, True)))")
|
18db8ba3d0e9ff93c63af2a457f14712a81ea2b2ef7fc7860c6d80108820d1ec
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"""Tests for computational algebraic number field theory. """
from sympy import (S, Rational, Symbol, Poly, sqrt, I, oo, Tuple, expand,
pi, cos, sin, exp)
from sympy.utilities.pytest import raises, slow
from sympy.core.compatibility import range
from sympy.polys.numberfields import (
minimal_polynomial,
primitive_element,
is_isomorphism_possible,
field_isomorphism_pslq,
field_isomorphism,
to_number_field,
AlgebraicNumber,
isolate, IntervalPrinter,
)
from sympy.polys.polyerrors import (
IsomorphismFailed,
NotAlgebraic,
GeneratorsError,
)
from sympy.polys.polyclasses import DMP
from sympy.polys.domains import QQ
from sympy.polys.rootoftools import rootof
from sympy.polys.polytools import degree
from sympy.abc import x, y, z
Q = Rational
def test_minimal_polynomial():
assert minimal_polynomial(-7, x) == x + 7
assert minimal_polynomial(-1, x) == x + 1
assert minimal_polynomial( 0, x) == x
assert minimal_polynomial( 1, x) == x - 1
assert minimal_polynomial( 7, x) == x - 7
assert minimal_polynomial(sqrt(2), x) == x**2 - 2
assert minimal_polynomial(sqrt(5), x) == x**2 - 5
assert minimal_polynomial(sqrt(6), x) == x**2 - 6
assert minimal_polynomial(2*sqrt(2), x) == x**2 - 8
assert minimal_polynomial(3*sqrt(5), x) == x**2 - 45
assert minimal_polynomial(4*sqrt(6), x) == x**2 - 96
assert minimal_polynomial(2*sqrt(2) + 3, x) == x**2 - 6*x + 1
assert minimal_polynomial(3*sqrt(5) + 6, x) == x**2 - 12*x - 9
assert minimal_polynomial(4*sqrt(6) + 7, x) == x**2 - 14*x - 47
assert minimal_polynomial(2*sqrt(2) - 3, x) == x**2 + 6*x + 1
assert minimal_polynomial(3*sqrt(5) - 6, x) == x**2 + 12*x - 9
assert minimal_polynomial(4*sqrt(6) - 7, x) == x**2 + 14*x - 47
assert minimal_polynomial(sqrt(1 + sqrt(6)), x) == x**4 - 2*x**2 - 5
assert minimal_polynomial(sqrt(I + sqrt(6)), x) == x**8 - 10*x**4 + 49
assert minimal_polynomial(2*I + sqrt(2 + I), x) == x**4 + 4*x**2 + 8*x + 37
assert minimal_polynomial(sqrt(2) + sqrt(3), x) == x**4 - 10*x**2 + 1
assert minimal_polynomial(
sqrt(2) + sqrt(3) + sqrt(6), x) == x**4 - 22*x**2 - 48*x - 23
a = 1 - 9*sqrt(2) + 7*sqrt(3)
assert minimal_polynomial(
1/a, x) == 392*x**4 - 1232*x**3 + 612*x**2 + 4*x - 1
assert minimal_polynomial(
1/sqrt(a), x) == 392*x**8 - 1232*x**6 + 612*x**4 + 4*x**2 - 1
raises(NotAlgebraic, lambda: minimal_polynomial(oo, x))
raises(NotAlgebraic, lambda: minimal_polynomial(2**y, x))
raises(NotAlgebraic, lambda: minimal_polynomial(sin(1), x))
assert minimal_polynomial(sqrt(2)).dummy_eq(x**2 - 2)
assert minimal_polynomial(sqrt(2), x) == x**2 - 2
assert minimal_polynomial(sqrt(2), polys=True) == Poly(x**2 - 2)
assert minimal_polynomial(sqrt(2), x, polys=True) == Poly(x**2 - 2)
assert minimal_polynomial(sqrt(2), x, polys=True, compose=False) == Poly(x**2 - 2)
a = AlgebraicNumber(sqrt(2))
b = AlgebraicNumber(sqrt(3))
assert minimal_polynomial(a, x) == x**2 - 2
assert minimal_polynomial(b, x) == x**2 - 3
assert minimal_polynomial(a, x, polys=True) == Poly(x**2 - 2)
assert minimal_polynomial(b, x, polys=True) == Poly(x**2 - 3)
assert minimal_polynomial(sqrt(a/2 + 17), x) == 2*x**4 - 68*x**2 + 577
assert minimal_polynomial(sqrt(b/2 + 17), x) == 4*x**4 - 136*x**2 + 1153
a, b = sqrt(2)/3 + 7, AlgebraicNumber(sqrt(2)/3 + 7)
f = 81*x**8 - 2268*x**6 - 4536*x**5 + 22644*x**4 + 63216*x**3 - \
31608*x**2 - 189648*x + 141358
assert minimal_polynomial(sqrt(a) + sqrt(sqrt(a)), x) == f
assert minimal_polynomial(sqrt(b) + sqrt(sqrt(b)), x) == f
assert minimal_polynomial(
a**Q(3, 2), x) == 729*x**4 - 506898*x**2 + 84604519
# issue 5994
eq = S('''
-1/(800*sqrt(-1/240 + 1/(18000*(-1/17280000 +
sqrt(15)*I/28800000)**(1/3)) + 2*(-1/17280000 +
sqrt(15)*I/28800000)**(1/3)))''')
assert minimal_polynomial(eq, x) == 8000*x**2 - 1
ex = 1 + sqrt(2) + sqrt(3)
mp = minimal_polynomial(ex, x)
assert mp == x**4 - 4*x**3 - 4*x**2 + 16*x - 8
ex = 1/(1 + sqrt(2) + sqrt(3))
mp = minimal_polynomial(ex, x)
assert mp == 8*x**4 - 16*x**3 + 4*x**2 + 4*x - 1
p = (expand((1 + sqrt(2) - 2*sqrt(3) + sqrt(7))**3))**Rational(1, 3)
mp = minimal_polynomial(p, x)
assert mp == x**8 - 8*x**7 - 56*x**6 + 448*x**5 + 480*x**4 - 5056*x**3 + 1984*x**2 + 7424*x - 3008
p = expand((1 + sqrt(2) - 2*sqrt(3) + sqrt(7))**3)
mp = minimal_polynomial(p, x)
assert mp == x**8 - 512*x**7 - 118208*x**6 + 31131136*x**5 + 647362560*x**4 - 56026611712*x**3 + 116994310144*x**2 + 404854931456*x - 27216576512
assert minimal_polynomial(S("-sqrt(5)/2 - 1/2 + (-sqrt(5)/2 - 1/2)**2"), x) == x - 1
a = 1 + sqrt(2)
assert minimal_polynomial((a*sqrt(2) + a)**3, x) == x**2 - 198*x + 1
p = 1/(1 + sqrt(2) + sqrt(3))
assert minimal_polynomial(p, x, compose=False) == 8*x**4 - 16*x**3 + 4*x**2 + 4*x - 1
p = 2/(1 + sqrt(2) + sqrt(3))
assert minimal_polynomial(p, x, compose=False) == x**4 - 4*x**3 + 2*x**2 + 4*x - 2
assert minimal_polynomial(1 + sqrt(2)*I, x, compose=False) == x**2 - 2*x + 3
assert minimal_polynomial(1/(1 + sqrt(2)) + 1, x, compose=False) == x**2 - 2
assert minimal_polynomial(sqrt(2)*I + I*(1 + sqrt(2)), x,
compose=False) == x**4 + 18*x**2 + 49
# minimal polynomial of I
assert minimal_polynomial(I, x, domain=QQ.algebraic_field(I)) == x - I
K = QQ.algebraic_field(I*(sqrt(2) + 1))
assert minimal_polynomial(I, x, domain=K) == x - I
assert minimal_polynomial(I, x, domain=QQ) == x**2 + 1
assert minimal_polynomial(I, x, domain='QQ(y)') == x**2 + 1
def test_minimal_polynomial_hi_prec():
p = 1/sqrt(1 - 9*sqrt(2) + 7*sqrt(3) + S(1)/10**30)
mp = minimal_polynomial(p, x)
# checked with Wolfram Alpha
assert mp.coeff(x**6) == -1232000000000000000000000000001223999999999999999999999999999987999999999999999999999999999996000000000000000000000000000000
def test_minimal_polynomial_sq():
from sympy import Add, expand_multinomial
p = expand_multinomial((1 + 5*sqrt(2) + 2*sqrt(3))**3)
mp = minimal_polynomial(p**Rational(1, 3), x)
assert mp == x**4 - 4*x**3 - 118*x**2 + 244*x + 1321
p = expand_multinomial((1 + sqrt(2) - 2*sqrt(3) + sqrt(7))**3)
mp = minimal_polynomial(p**Rational(1, 3), x)
assert mp == x**8 - 8*x**7 - 56*x**6 + 448*x**5 + 480*x**4 - 5056*x**3 + 1984*x**2 + 7424*x - 3008
p = Add(*[sqrt(i) for i in range(1, 12)])
mp = minimal_polynomial(p, x)
assert mp.subs({x: 0}) == -71965773323122507776
def test_minpoly_compose():
# issue 6868
eq = S('''
-1/(800*sqrt(-1/240 + 1/(18000*(-1/17280000 +
sqrt(15)*I/28800000)**(1/3)) + 2*(-1/17280000 +
sqrt(15)*I/28800000)**(1/3)))''')
mp = minimal_polynomial(eq + 3, x)
assert mp == 8000*x**2 - 48000*x + 71999
# issue 5888
assert minimal_polynomial(exp(I*pi/8), x) == x**8 + 1
mp = minimal_polynomial(sin(pi/7) + sqrt(2), x)
assert mp == 4096*x**12 - 63488*x**10 + 351488*x**8 - 826496*x**6 + \
770912*x**4 - 268432*x**2 + 28561
mp = minimal_polynomial(cos(pi/7) + sqrt(2), x)
assert mp == 64*x**6 - 64*x**5 - 432*x**4 + 304*x**3 + 712*x**2 - \
232*x - 239
mp = minimal_polynomial(exp(I*pi/7) + sqrt(2), x)
assert mp == x**12 - 2*x**11 - 9*x**10 + 16*x**9 + 43*x**8 - 70*x**7 - 97*x**6 + 126*x**5 + 211*x**4 - 212*x**3 - 37*x**2 + 142*x + 127
mp = minimal_polynomial(sin(pi/7) + sqrt(2), x)
assert mp == 4096*x**12 - 63488*x**10 + 351488*x**8 - 826496*x**6 + \
770912*x**4 - 268432*x**2 + 28561
mp = minimal_polynomial(cos(pi/7) + sqrt(2), x)
assert mp == 64*x**6 - 64*x**5 - 432*x**4 + 304*x**3 + 712*x**2 - \
232*x - 239
mp = minimal_polynomial(exp(I*pi/7) + sqrt(2), x)
assert mp == x**12 - 2*x**11 - 9*x**10 + 16*x**9 + 43*x**8 - 70*x**7 - 97*x**6 + 126*x**5 + 211*x**4 - 212*x**3 - 37*x**2 + 142*x + 127
mp = minimal_polynomial(exp(2*I*pi/7), x)
assert mp == x**6 + x**5 + x**4 + x**3 + x**2 + x + 1
mp = minimal_polynomial(exp(2*I*pi/15), x)
assert mp == x**8 - x**7 + x**5 - x**4 + x**3 - x + 1
mp = minimal_polynomial(cos(2*pi/7), x)
assert mp == 8*x**3 + 4*x**2 - 4*x - 1
mp = minimal_polynomial(sin(2*pi/7), x)
ex = (5*cos(2*pi/7) - 7)/(9*cos(pi/7) - 5*cos(3*pi/7))
mp = minimal_polynomial(ex, x)
assert mp == x**3 + 2*x**2 - x - 1
assert minimal_polynomial(-1/(2*cos(pi/7)), x) == x**3 + 2*x**2 - x - 1
assert minimal_polynomial(sin(2*pi/15), x) == \
256*x**8 - 448*x**6 + 224*x**4 - 32*x**2 + 1
assert minimal_polynomial(sin(5*pi/14), x) == 8*x**3 - 4*x**2 - 4*x + 1
assert minimal_polynomial(cos(pi/15), x) == 16*x**4 + 8*x**3 - 16*x**2 - 8*x + 1
ex = rootof(x**3 +x*4 + 1, 0)
mp = minimal_polynomial(ex, x)
assert mp == x**3 + 4*x + 1
mp = minimal_polynomial(ex + 1, x)
assert mp == x**3 - 3*x**2 + 7*x - 4
assert minimal_polynomial(exp(I*pi/3), x) == x**2 - x + 1
assert minimal_polynomial(exp(I*pi/4), x) == x**4 + 1
assert minimal_polynomial(exp(I*pi/6), x) == x**4 - x**2 + 1
assert minimal_polynomial(exp(I*pi/9), x) == x**6 - x**3 + 1
assert minimal_polynomial(exp(I*pi/10), x) == x**8 - x**6 + x**4 - x**2 + 1
assert minimal_polynomial(sin(pi/9), x) == 64*x**6 - 96*x**4 + 36*x**2 - 3
assert minimal_polynomial(sin(pi/11), x) == 1024*x**10 - 2816*x**8 + \
2816*x**6 - 1232*x**4 + 220*x**2 - 11
ex = 2**Rational(1, 3)*exp(Rational(2, 3)*I*pi)
assert minimal_polynomial(ex, x) == x**3 - 2
raises(NotAlgebraic, lambda: minimal_polynomial(cos(pi*sqrt(2)), x))
raises(NotAlgebraic, lambda: minimal_polynomial(sin(pi*sqrt(2)), x))
raises(NotAlgebraic, lambda: minimal_polynomial(exp(I*pi*sqrt(2)), x))
# issue 5934
ex = 1/(-36000 - 7200*sqrt(5) + (12*sqrt(10)*sqrt(sqrt(5) + 5) +
24*sqrt(10)*sqrt(-sqrt(5) + 5))**2) + 1
raises(ZeroDivisionError, lambda: minimal_polynomial(ex, x))
ex = sqrt(1 + 2**Rational(1,3)) + sqrt(1 + 2**Rational(1,4)) + sqrt(2)
mp = minimal_polynomial(ex, x)
assert degree(mp) == 48 and mp.subs({x:0}) == -16630256576
def test_minpoly_issue_7113():
# see discussion in https://github.com/sympy/sympy/pull/2234
from sympy.simplify.simplify import nsimplify
r = nsimplify(pi, tolerance=0.000000001)
mp = minimal_polynomial(r, x)
assert mp == 1768292677839237920489538677417507171630859375*x**109 - \
2734577732179183863586489182929671773182898498218854181690460140337930774573792597743853652058046464
def test_minpoly_issue_7574():
ex = -(-1)**Rational(1, 3) + (-1)**Rational(2,3)
assert minimal_polynomial(ex, x) == x + 1
def test_primitive_element():
assert primitive_element([sqrt(2)], x) == (x**2 - 2, [1])
assert primitive_element(
[sqrt(2), sqrt(3)], x) == (x**4 - 10*x**2 + 1, [1, 1])
assert primitive_element([sqrt(2)], x, polys=True) == (Poly(x**2 - 2), [1])
assert primitive_element([sqrt(
2), sqrt(3)], x, polys=True) == (Poly(x**4 - 10*x**2 + 1), [1, 1])
assert primitive_element(
[sqrt(2)], x, ex=True) == (x**2 - 2, [1], [[1, 0]])
assert primitive_element([sqrt(2), sqrt(3)], x, ex=True) == \
(x**4 - 10*x**2 + 1, [1, 1], [[Q(1, 2), 0, -Q(9, 2), 0], [-
Q(1, 2), 0, Q(11, 2), 0]])
assert primitive_element(
[sqrt(2)], x, ex=True, polys=True) == (Poly(x**2 - 2), [1], [[1, 0]])
assert primitive_element([sqrt(2), sqrt(3)], x, ex=True, polys=True) == \
(Poly(x**4 - 10*x**2 + 1), [1, 1], [[Q(1, 2), 0, -Q(9, 2),
0], [-Q(1, 2), 0, Q(11, 2), 0]])
assert primitive_element([sqrt(2)], polys=True) == (Poly(x**2 - 2), [1])
raises(ValueError, lambda: primitive_element([], x, ex=False))
raises(ValueError, lambda: primitive_element([], x, ex=True))
# Issue 14117
a, b = I*sqrt(2*sqrt(2) + 3), I*sqrt(-2*sqrt(2) + 3)
assert primitive_element([a, b, I], x) == (x**4 + 6*x**2 + 1, [1, 0, 0])
def test_field_isomorphism_pslq():
a = AlgebraicNumber(I)
b = AlgebraicNumber(I*sqrt(3))
raises(NotImplementedError, lambda: field_isomorphism_pslq(a, b))
a = AlgebraicNumber(sqrt(2))
b = AlgebraicNumber(sqrt(3))
c = AlgebraicNumber(sqrt(7))
d = AlgebraicNumber(sqrt(2) + sqrt(3))
e = AlgebraicNumber(sqrt(2) + sqrt(3) + sqrt(7))
assert field_isomorphism_pslq(a, a) == [1, 0]
assert field_isomorphism_pslq(a, b) is None
assert field_isomorphism_pslq(a, c) is None
assert field_isomorphism_pslq(a, d) == [Q(1, 2), 0, -Q(9, 2), 0]
assert field_isomorphism_pslq(
a, e) == [Q(1, 80), 0, -Q(1, 2), 0, Q(59, 20), 0]
assert field_isomorphism_pslq(b, a) is None
assert field_isomorphism_pslq(b, b) == [1, 0]
assert field_isomorphism_pslq(b, c) is None
assert field_isomorphism_pslq(b, d) == [-Q(1, 2), 0, Q(11, 2), 0]
assert field_isomorphism_pslq(b, e) == [-Q(
3, 640), 0, Q(67, 320), 0, -Q(297, 160), 0, Q(313, 80), 0]
assert field_isomorphism_pslq(c, a) is None
assert field_isomorphism_pslq(c, b) is None
assert field_isomorphism_pslq(c, c) == [1, 0]
assert field_isomorphism_pslq(c, d) is None
assert field_isomorphism_pslq(c, e) == [Q(
3, 640), 0, -Q(71, 320), 0, Q(377, 160), 0, -Q(469, 80), 0]
assert field_isomorphism_pslq(d, a) is None
assert field_isomorphism_pslq(d, b) is None
assert field_isomorphism_pslq(d, c) is None
assert field_isomorphism_pslq(d, d) == [1, 0]
assert field_isomorphism_pslq(d, e) == [-Q(
3, 640), 0, Q(71, 320), 0, -Q(377, 160), 0, Q(549, 80), 0]
assert field_isomorphism_pslq(e, a) is None
assert field_isomorphism_pslq(e, b) is None
assert field_isomorphism_pslq(e, c) is None
assert field_isomorphism_pslq(e, d) is None
assert field_isomorphism_pslq(e, e) == [1, 0]
f = AlgebraicNumber(3*sqrt(2) + 8*sqrt(7) - 5)
assert field_isomorphism_pslq(
f, e) == [Q(3, 80), 0, -Q(139, 80), 0, Q(347, 20), 0, -Q(761, 20), -5]
def test_field_isomorphism():
assert field_isomorphism(3, sqrt(2)) == [3]
assert field_isomorphism( I*sqrt(3), I*sqrt(3)/2) == [ 2, 0]
assert field_isomorphism(-I*sqrt(3), I*sqrt(3)/2) == [-2, 0]
assert field_isomorphism( I*sqrt(3), -I*sqrt(3)/2) == [-2, 0]
assert field_isomorphism(-I*sqrt(3), -I*sqrt(3)/2) == [ 2, 0]
assert field_isomorphism( 2*I*sqrt(3)/7, 5*I*sqrt(3)/3) == [ S(6)/35, 0]
assert field_isomorphism(-2*I*sqrt(3)/7, 5*I*sqrt(3)/3) == [-S(6)/35, 0]
assert field_isomorphism( 2*I*sqrt(3)/7, -5*I*sqrt(3)/3) == [-S(6)/35, 0]
assert field_isomorphism(-2*I*sqrt(3)/7, -5*I*sqrt(3)/3) == [ S(6)/35, 0]
assert field_isomorphism(
2*I*sqrt(3)/7 + 27, 5*I*sqrt(3)/3) == [ S(6)/35, 27]
assert field_isomorphism(
-2*I*sqrt(3)/7 + 27, 5*I*sqrt(3)/3) == [-S(6)/35, 27]
assert field_isomorphism(
2*I*sqrt(3)/7 + 27, -5*I*sqrt(3)/3) == [-S(6)/35, 27]
assert field_isomorphism(
-2*I*sqrt(3)/7 + 27, -5*I*sqrt(3)/3) == [ S(6)/35, 27]
p = AlgebraicNumber( sqrt(2) + sqrt(3))
q = AlgebraicNumber(-sqrt(2) + sqrt(3))
r = AlgebraicNumber( sqrt(2) - sqrt(3))
s = AlgebraicNumber(-sqrt(2) - sqrt(3))
pos_coeffs = [ S(1)/2, S(0), -S(9)/2, S(0)]
neg_coeffs = [-S(1)/2, S(0), S(9)/2, S(0)]
a = AlgebraicNumber(sqrt(2))
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == pos_coeffs
assert field_isomorphism(a, q, fast=True) == neg_coeffs
assert field_isomorphism(a, r, fast=True) == pos_coeffs
assert field_isomorphism(a, s, fast=True) == neg_coeffs
assert field_isomorphism(a, p, fast=False) == pos_coeffs
assert field_isomorphism(a, q, fast=False) == neg_coeffs
assert field_isomorphism(a, r, fast=False) == pos_coeffs
assert field_isomorphism(a, s, fast=False) == neg_coeffs
a = AlgebraicNumber(-sqrt(2))
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == neg_coeffs
assert field_isomorphism(a, q, fast=True) == pos_coeffs
assert field_isomorphism(a, r, fast=True) == neg_coeffs
assert field_isomorphism(a, s, fast=True) == pos_coeffs
assert field_isomorphism(a, p, fast=False) == neg_coeffs
assert field_isomorphism(a, q, fast=False) == pos_coeffs
assert field_isomorphism(a, r, fast=False) == neg_coeffs
assert field_isomorphism(a, s, fast=False) == pos_coeffs
pos_coeffs = [ S(1)/2, S(0), -S(11)/2, S(0)]
neg_coeffs = [-S(1)/2, S(0), S(11)/2, S(0)]
a = AlgebraicNumber(sqrt(3))
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == neg_coeffs
assert field_isomorphism(a, q, fast=True) == neg_coeffs
assert field_isomorphism(a, r, fast=True) == pos_coeffs
assert field_isomorphism(a, s, fast=True) == pos_coeffs
assert field_isomorphism(a, p, fast=False) == neg_coeffs
assert field_isomorphism(a, q, fast=False) == neg_coeffs
assert field_isomorphism(a, r, fast=False) == pos_coeffs
assert field_isomorphism(a, s, fast=False) == pos_coeffs
a = AlgebraicNumber(-sqrt(3))
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == pos_coeffs
assert field_isomorphism(a, q, fast=True) == pos_coeffs
assert field_isomorphism(a, r, fast=True) == neg_coeffs
assert field_isomorphism(a, s, fast=True) == neg_coeffs
assert field_isomorphism(a, p, fast=False) == pos_coeffs
assert field_isomorphism(a, q, fast=False) == pos_coeffs
assert field_isomorphism(a, r, fast=False) == neg_coeffs
assert field_isomorphism(a, s, fast=False) == neg_coeffs
pos_coeffs = [ S(3)/2, S(0), -S(33)/2, -S(8)]
neg_coeffs = [-S(3)/2, S(0), S(33)/2, -S(8)]
a = AlgebraicNumber(3*sqrt(3) - 8)
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == neg_coeffs
assert field_isomorphism(a, q, fast=True) == neg_coeffs
assert field_isomorphism(a, r, fast=True) == pos_coeffs
assert field_isomorphism(a, s, fast=True) == pos_coeffs
assert field_isomorphism(a, p, fast=False) == neg_coeffs
assert field_isomorphism(a, q, fast=False) == neg_coeffs
assert field_isomorphism(a, r, fast=False) == pos_coeffs
assert field_isomorphism(a, s, fast=False) == pos_coeffs
a = AlgebraicNumber(3*sqrt(2) + 2*sqrt(3) + 1)
pos_1_coeffs = [ S(1)/2, S(0), -S(5)/2, S(1)]
neg_5_coeffs = [-S(5)/2, S(0), S(49)/2, S(1)]
pos_5_coeffs = [ S(5)/2, S(0), -S(49)/2, S(1)]
neg_1_coeffs = [-S(1)/2, S(0), S(5)/2, S(1)]
assert is_isomorphism_possible(a, p) is True
assert is_isomorphism_possible(a, q) is True
assert is_isomorphism_possible(a, r) is True
assert is_isomorphism_possible(a, s) is True
assert field_isomorphism(a, p, fast=True) == pos_1_coeffs
assert field_isomorphism(a, q, fast=True) == neg_5_coeffs
assert field_isomorphism(a, r, fast=True) == pos_5_coeffs
assert field_isomorphism(a, s, fast=True) == neg_1_coeffs
assert field_isomorphism(a, p, fast=False) == pos_1_coeffs
assert field_isomorphism(a, q, fast=False) == neg_5_coeffs
assert field_isomorphism(a, r, fast=False) == pos_5_coeffs
assert field_isomorphism(a, s, fast=False) == neg_1_coeffs
a = AlgebraicNumber(sqrt(2))
b = AlgebraicNumber(sqrt(3))
c = AlgebraicNumber(sqrt(7))
assert is_isomorphism_possible(a, b) is True
assert is_isomorphism_possible(b, a) is True
assert is_isomorphism_possible(c, p) is False
assert field_isomorphism(sqrt(2), sqrt(3), fast=True) is None
assert field_isomorphism(sqrt(3), sqrt(2), fast=True) is None
assert field_isomorphism(sqrt(2), sqrt(3), fast=False) is None
assert field_isomorphism(sqrt(3), sqrt(2), fast=False) is None
def test_to_number_field():
assert to_number_field(sqrt(2)) == AlgebraicNumber(sqrt(2))
assert to_number_field(
[sqrt(2), sqrt(3)]) == AlgebraicNumber(sqrt(2) + sqrt(3))
a = AlgebraicNumber(sqrt(2) + sqrt(3), [S(1)/2, S(0), -S(9)/2, S(0)])
assert to_number_field(sqrt(2), sqrt(2) + sqrt(3)) == a
assert to_number_field(sqrt(2), AlgebraicNumber(sqrt(2) + sqrt(3))) == a
raises(IsomorphismFailed, lambda: to_number_field(sqrt(2), sqrt(3)))
def test_AlgebraicNumber():
minpoly, root = x**2 - 2, sqrt(2)
a = AlgebraicNumber(root, gen=x)
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
assert a.root == root
assert a.alias is None
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is False
assert a.coeffs() == [S(1), S(0)]
assert a.native_coeffs() == [QQ(1), QQ(0)]
a = AlgebraicNumber(root, gen=x, alias='y')
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
assert a.root == root
assert a.alias == Symbol('y')
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is True
a = AlgebraicNumber(root, gen=x, alias=Symbol('y'))
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
assert a.root == root
assert a.alias == Symbol('y')
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is True
assert AlgebraicNumber(sqrt(2), []).rep == DMP([], QQ)
assert AlgebraicNumber(sqrt(2), ()).rep == DMP([], QQ)
assert AlgebraicNumber(sqrt(2), (0, 0)).rep == DMP([], QQ)
assert AlgebraicNumber(sqrt(2), [8]).rep == DMP([QQ(8)], QQ)
assert AlgebraicNumber(sqrt(2), [S(8)/3]).rep == DMP([QQ(8, 3)], QQ)
assert AlgebraicNumber(sqrt(2), [7, 3]).rep == DMP([QQ(7), QQ(3)], QQ)
assert AlgebraicNumber(
sqrt(2), [S(7)/9, S(3)/2]).rep == DMP([QQ(7, 9), QQ(3, 2)], QQ)
assert AlgebraicNumber(sqrt(2), [1, 2, 3]).rep == DMP([QQ(2), QQ(5)], QQ)
a = AlgebraicNumber(AlgebraicNumber(root, gen=x), [1, 2])
assert a.rep == DMP([QQ(1), QQ(2)], QQ)
assert a.root == root
assert a.alias is None
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is False
assert a.coeffs() == [S(1), S(2)]
assert a.native_coeffs() == [QQ(1), QQ(2)]
a = AlgebraicNumber((minpoly, root), [1, 2])
assert a.rep == DMP([QQ(1), QQ(2)], QQ)
assert a.root == root
assert a.alias is None
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is False
a = AlgebraicNumber((Poly(minpoly), root), [1, 2])
assert a.rep == DMP([QQ(1), QQ(2)], QQ)
assert a.root == root
assert a.alias is None
assert a.minpoly == minpoly
assert a.is_number
assert a.is_aliased is False
assert AlgebraicNumber( sqrt(3)).rep == DMP([ QQ(1), QQ(0)], QQ)
assert AlgebraicNumber(-sqrt(3)).rep == DMP([ QQ(1), QQ(0)], QQ)
a = AlgebraicNumber(sqrt(2))
b = AlgebraicNumber(sqrt(2))
assert a == b
c = AlgebraicNumber(sqrt(2), gen=x)
d = AlgebraicNumber(sqrt(2), gen=x)
assert a == b
assert a == c
a = AlgebraicNumber(sqrt(2), [1, 2])
b = AlgebraicNumber(sqrt(2), [1, 3])
assert a != b and a != sqrt(2) + 3
assert (a == x) is False and (a != x) is True
a = AlgebraicNumber(sqrt(2), [1, 0])
b = AlgebraicNumber(sqrt(2), [1, 0], alias=y)
assert a.as_poly(x) == Poly(x)
assert b.as_poly() == Poly(y)
assert a.as_expr() == sqrt(2)
assert a.as_expr(x) == x
assert b.as_expr() == sqrt(2)
assert b.as_expr(x) == x
a = AlgebraicNumber(sqrt(2), [2, 3])
b = AlgebraicNumber(sqrt(2), [2, 3], alias=y)
p = a.as_poly()
assert p == Poly(2*p.gen + 3)
assert a.as_poly(x) == Poly(2*x + 3)
assert b.as_poly() == Poly(2*y + 3)
assert a.as_expr() == 2*sqrt(2) + 3
assert a.as_expr(x) == 2*x + 3
assert b.as_expr() == 2*sqrt(2) + 3
assert b.as_expr(x) == 2*x + 3
a = AlgebraicNumber(sqrt(2))
b = to_number_field(sqrt(2))
assert a.args == b.args == (sqrt(2), Tuple(1, 0))
b = AlgebraicNumber(sqrt(2), alias='alpha')
assert b.args == (sqrt(2), Tuple(1, 0), Symbol('alpha'))
a = AlgebraicNumber(sqrt(2), [1, 2, 3])
assert a.args == (sqrt(2), Tuple(1, 2, 3))
def test_to_algebraic_integer():
a = AlgebraicNumber(sqrt(3), gen=x).to_algebraic_integer()
assert a.minpoly == x**2 - 3
assert a.root == sqrt(3)
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
a = AlgebraicNumber(2*sqrt(3), gen=x).to_algebraic_integer()
assert a.minpoly == x**2 - 12
assert a.root == 2*sqrt(3)
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
a = AlgebraicNumber(sqrt(3)/2, gen=x).to_algebraic_integer()
assert a.minpoly == x**2 - 12
assert a.root == 2*sqrt(3)
assert a.rep == DMP([QQ(1), QQ(0)], QQ)
a = AlgebraicNumber(sqrt(3)/2, [S(7)/19, 3], gen=x).to_algebraic_integer()
assert a.minpoly == x**2 - 12
assert a.root == 2*sqrt(3)
assert a.rep == DMP([QQ(7, 19), QQ(3)], QQ)
def test_IntervalPrinter():
ip = IntervalPrinter()
assert ip.doprint(x**Q(1, 3)) == "x**(mpi('1/3'))"
assert ip.doprint(sqrt(x)) == "x**(mpi('1/2'))"
def test_isolate():
assert isolate(1) == (1, 1)
assert isolate(S(1)/2) == (S(1)/2, S(1)/2)
assert isolate(sqrt(2)) == (1, 2)
assert isolate(-sqrt(2)) == (-2, -1)
assert isolate(sqrt(2), eps=S(1)/100) == (S(24)/17, S(17)/12)
assert isolate(-sqrt(2), eps=S(1)/100) == (-S(17)/12, -S(24)/17)
raises(NotImplementedError, lambda: isolate(I))
def test_minpoly_fraction_field():
assert minimal_polynomial(1/x, y) == -x*y + 1
assert minimal_polynomial(1 / (x + 1), y) == (x + 1)*y - 1
assert minimal_polynomial(sqrt(x), y) == y**2 - x
assert minimal_polynomial(sqrt(x + 1), y) == y**2 - x - 1
assert minimal_polynomial(sqrt(x) / x, y) == x*y**2 - 1
assert minimal_polynomial(sqrt(2) * sqrt(x), y) == y**2 - 2 * x
assert minimal_polynomial(sqrt(2) + sqrt(x), y) == \
y**4 + (-2*x - 4)*y**2 + x**2 - 4*x + 4
assert minimal_polynomial(x**Rational(1,3), y) == y**3 - x
assert minimal_polynomial(x**Rational(1,3) + sqrt(x), y) == \
y**6 - 3*x*y**4 - 2*x*y**3 + 3*x**2*y**2 - 6*x**2*y - x**3 + x**2
assert minimal_polynomial(sqrt(x) / z, y) == z**2*y**2 - x
assert minimal_polynomial(sqrt(x) / (z + 1), y) == (z**2 + 2*z + 1)*y**2 - x
assert minimal_polynomial(1/x, y, polys=True) == Poly(-x*y + 1, y)
assert minimal_polynomial(1 / (x + 1), y, polys=True) == \
Poly((x + 1)*y - 1, y)
assert minimal_polynomial(sqrt(x), y, polys=True) == Poly(y**2 - x, y)
assert minimal_polynomial(sqrt(x) / z, y, polys=True) == \
Poly(z**2*y**2 - x, y)
# this is (sqrt(1 + x**3)/x).integrate(x).diff(x) - sqrt(1 + x**3)/x
a = sqrt(x)/sqrt(1 + x**(-3)) - sqrt(x**3 + 1)/x + 1/(x**(S(5)/2)* \
(1 + x**(-3))**(S(3)/2)) + 1/(x**(S(11)/2)*(1 + x**(-3))**(S(3)/2))
assert minimal_polynomial(a, y) == y
raises(NotAlgebraic, lambda: minimal_polynomial(exp(x), y))
raises(GeneratorsError, lambda: minimal_polynomial(sqrt(x), x))
raises(GeneratorsError, lambda: minimal_polynomial(sqrt(x) - y, x))
raises(NotImplementedError, lambda: minimal_polynomial(sqrt(x), y, compose=False))
@slow
def test_minpoly_fraction_field_slow():
assert minimal_polynomial(minimal_polynomial(sqrt(x**Rational(1,5) - 1),
y).subs(y, sqrt(x**Rational(1,5) - 1)), z) == z
def test_minpoly_domain():
assert minimal_polynomial(sqrt(2), x, domain=QQ.algebraic_field(sqrt(2))) == \
x - sqrt(2)
assert minimal_polynomial(sqrt(8), x, domain=QQ.algebraic_field(sqrt(2))) == \
x - 2*sqrt(2)
assert minimal_polynomial(sqrt(Rational(3,2)), x,
domain=QQ.algebraic_field(sqrt(2))) == 2*x**2 - 3
raises(NotAlgebraic, lambda: minimal_polynomial(y, x, domain=QQ))
def test_issue_14831():
a = -2*sqrt(2)*sqrt(12*sqrt(2) + 17)
assert minimal_polynomial(a, x) == x**2 + 16*x - 8
e = (-3*sqrt(12*sqrt(2) + 17) + 12*sqrt(2) +
17 - 2*sqrt(2)*sqrt(12*sqrt(2) + 17))
assert minimal_polynomial(e, x) == x
|
8f5faf63be4a0d000482744060a9bd3062daba2b51633f6d413afe4968cee0ba
|
"""Tests for user-friendly public interface to polynomial functions. """
from sympy.polys.polytools import (
Poly, PurePoly, poly,
parallel_poly_from_expr,
degree, degree_list,
total_degree,
LC, LM, LT,
pdiv, prem, pquo, pexquo,
div, rem, quo, exquo,
half_gcdex, gcdex, invert,
subresultants,
resultant, discriminant,
terms_gcd, cofactors,
gcd, gcd_list,
lcm, lcm_list,
trunc,
monic, content, primitive,
compose, decompose,
sturm,
gff_list, gff,
sqf_norm, sqf_part, sqf_list, sqf,
factor_list, factor,
intervals, refine_root, count_roots,
real_roots, nroots, ground_roots,
nth_power_roots_poly,
cancel, reduced, groebner,
GroebnerBasis, is_zero_dimensional,
_torational_factor_list,
to_rational_coeffs)
from sympy.polys.polyerrors import (
MultivariatePolynomialError,
ExactQuotientFailed,
PolificationFailed,
ComputationFailed,
UnificationFailed,
RefinementFailed,
GeneratorsNeeded,
GeneratorsError,
PolynomialError,
CoercionFailed,
DomainError,
OptionError,
FlagError)
from sympy.polys.polyclasses import DMP
from sympy.polys.fields import field
from sympy.polys.domains import FF, ZZ, QQ, RR, EX
from sympy.polys.domains.realfield import RealField
from sympy.polys.orderings import lex, grlex, grevlex
from sympy import (
S, Integer, Rational, Float, Mul, Symbol, sqrt, Piecewise, Derivative,
exp, sin, tanh, expand, oo, I, pi, re, im, rootof, Eq, Tuple, Expr, diff)
from sympy.core.basic import _aresame
from sympy.core.compatibility import iterable
from sympy.core.mul import _keep_coeff
from sympy.utilities.pytest import raises, XFAIL
from sympy.simplify import simplify
from sympy.abc import a, b, c, d, p, q, t, w, x, y, z
from sympy import MatrixSymbol
def _epsilon_eq(a, b):
for x, y in zip(a, b):
if abs(x - y) > 1e-10:
return False
return True
def _strict_eq(a, b):
if type(a) == type(b):
if iterable(a):
if len(a) == len(b):
return all(_strict_eq(c, d) for c, d in zip(a, b))
else:
return False
else:
return isinstance(a, Poly) and a.eq(b, strict=True)
else:
return False
def test_Poly_from_dict():
K = FF(3)
assert Poly.from_dict(
{0: 1, 1: 2}, gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_dict(
{0: 1, 1: 5}, gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_dict(
{(0,): 1, (1,): 2}, gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_dict(
{(0,): 1, (1,): 5}, gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_dict({(0, 0): 1, (1, 1): 2}, gens=(
x, y), domain=K).rep == DMP([[K(2), K(0)], [K(1)]], K)
assert Poly.from_dict({0: 1, 1: 2}, gens=x).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_dict(
{0: 1, 1: 2}, gens=x, field=True).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_dict(
{0: 1, 1: 2}, gens=x, domain=ZZ).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_dict(
{0: 1, 1: 2}, gens=x, domain=QQ).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_dict(
{(0,): 1, (1,): 2}, gens=x).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_dict(
{(0,): 1, (1,): 2}, gens=x, field=True).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_dict(
{(0,): 1, (1,): 2}, gens=x, domain=ZZ).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_dict(
{(0,): 1, (1,): 2}, gens=x, domain=QQ).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_dict({(1,): sin(y)}, gens=x, composite=False) == \
Poly(sin(y)*x, x, domain='EX')
assert Poly.from_dict({(1,): y}, gens=x, composite=False) == \
Poly(y*x, x, domain='EX')
assert Poly.from_dict({(1, 1): 1}, gens=(x, y), composite=False) == \
Poly(x*y, x, y, domain='ZZ')
assert Poly.from_dict({(1, 0): y}, gens=(x, z), composite=False) == \
Poly(y*x, x, z, domain='EX')
def test_Poly_from_list():
K = FF(3)
assert Poly.from_list([2, 1], gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_list([5, 1], gens=x, domain=K).rep == DMP([K(2), K(1)], K)
assert Poly.from_list([2, 1], gens=x).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_list([2, 1], gens=x, field=True).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_list([2, 1], gens=x, domain=ZZ).rep == DMP([ZZ(2), ZZ(1)], ZZ)
assert Poly.from_list([2, 1], gens=x, domain=QQ).rep == DMP([QQ(2), QQ(1)], QQ)
assert Poly.from_list([0, 1.0], gens=x).rep == DMP([RR(1.0)], RR)
assert Poly.from_list([1.0, 0], gens=x).rep == DMP([RR(1.0), RR(0.0)], RR)
raises(MultivariatePolynomialError, lambda: Poly.from_list([[]], gens=(x, y)))
def test_Poly_from_poly():
f = Poly(x + 7, x, domain=ZZ)
g = Poly(x + 2, x, modulus=3)
h = Poly(x + y, x, y, domain=ZZ)
K = FF(3)
assert Poly.from_poly(f) == f
assert Poly.from_poly(f, domain=K).rep == DMP([K(1), K(1)], K)
assert Poly.from_poly(f, domain=ZZ).rep == DMP([1, 7], ZZ)
assert Poly.from_poly(f, domain=QQ).rep == DMP([1, 7], QQ)
assert Poly.from_poly(f, gens=x) == f
assert Poly.from_poly(f, gens=x, domain=K).rep == DMP([K(1), K(1)], K)
assert Poly.from_poly(f, gens=x, domain=ZZ).rep == DMP([1, 7], ZZ)
assert Poly.from_poly(f, gens=x, domain=QQ).rep == DMP([1, 7], QQ)
assert Poly.from_poly(f, gens=y) == Poly(x + 7, y, domain='ZZ[x]')
raises(CoercionFailed, lambda: Poly.from_poly(f, gens=y, domain=K))
raises(CoercionFailed, lambda: Poly.from_poly(f, gens=y, domain=ZZ))
raises(CoercionFailed, lambda: Poly.from_poly(f, gens=y, domain=QQ))
assert Poly.from_poly(f, gens=(x, y)) == Poly(x + 7, x, y, domain='ZZ')
assert Poly.from_poly(
f, gens=(x, y), domain=ZZ) == Poly(x + 7, x, y, domain='ZZ')
assert Poly.from_poly(
f, gens=(x, y), domain=QQ) == Poly(x + 7, x, y, domain='QQ')
assert Poly.from_poly(
f, gens=(x, y), modulus=3) == Poly(x + 7, x, y, domain='FF(3)')
K = FF(2)
assert Poly.from_poly(g) == g
assert Poly.from_poly(g, domain=ZZ).rep == DMP([1, -1], ZZ)
raises(CoercionFailed, lambda: Poly.from_poly(g, domain=QQ))
assert Poly.from_poly(g, domain=K).rep == DMP([K(1), K(0)], K)
assert Poly.from_poly(g, gens=x) == g
assert Poly.from_poly(g, gens=x, domain=ZZ).rep == DMP([1, -1], ZZ)
raises(CoercionFailed, lambda: Poly.from_poly(g, gens=x, domain=QQ))
assert Poly.from_poly(g, gens=x, domain=K).rep == DMP([K(1), K(0)], K)
K = FF(3)
assert Poly.from_poly(h) == h
assert Poly.from_poly(
h, domain=ZZ).rep == DMP([[ZZ(1)], [ZZ(1), ZZ(0)]], ZZ)
assert Poly.from_poly(
h, domain=QQ).rep == DMP([[QQ(1)], [QQ(1), QQ(0)]], QQ)
assert Poly.from_poly(h, domain=K).rep == DMP([[K(1)], [K(1), K(0)]], K)
assert Poly.from_poly(h, gens=x) == Poly(x + y, x, domain=ZZ[y])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=x, domain=ZZ))
assert Poly.from_poly(
h, gens=x, domain=ZZ[y]) == Poly(x + y, x, domain=ZZ[y])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=x, domain=QQ))
assert Poly.from_poly(
h, gens=x, domain=QQ[y]) == Poly(x + y, x, domain=QQ[y])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=x, modulus=3))
assert Poly.from_poly(h, gens=y) == Poly(x + y, y, domain=ZZ[x])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=y, domain=ZZ))
assert Poly.from_poly(
h, gens=y, domain=ZZ[x]) == Poly(x + y, y, domain=ZZ[x])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=y, domain=QQ))
assert Poly.from_poly(
h, gens=y, domain=QQ[x]) == Poly(x + y, y, domain=QQ[x])
raises(CoercionFailed, lambda: Poly.from_poly(h, gens=y, modulus=3))
assert Poly.from_poly(h, gens=(x, y)) == h
assert Poly.from_poly(
h, gens=(x, y), domain=ZZ).rep == DMP([[ZZ(1)], [ZZ(1), ZZ(0)]], ZZ)
assert Poly.from_poly(
h, gens=(x, y), domain=QQ).rep == DMP([[QQ(1)], [QQ(1), QQ(0)]], QQ)
assert Poly.from_poly(
h, gens=(x, y), domain=K).rep == DMP([[K(1)], [K(1), K(0)]], K)
assert Poly.from_poly(
h, gens=(y, x)).rep == DMP([[ZZ(1)], [ZZ(1), ZZ(0)]], ZZ)
assert Poly.from_poly(
h, gens=(y, x), domain=ZZ).rep == DMP([[ZZ(1)], [ZZ(1), ZZ(0)]], ZZ)
assert Poly.from_poly(
h, gens=(y, x), domain=QQ).rep == DMP([[QQ(1)], [QQ(1), QQ(0)]], QQ)
assert Poly.from_poly(
h, gens=(y, x), domain=K).rep == DMP([[K(1)], [K(1), K(0)]], K)
assert Poly.from_poly(
h, gens=(x, y), field=True).rep == DMP([[QQ(1)], [QQ(1), QQ(0)]], QQ)
assert Poly.from_poly(
h, gens=(x, y), field=True).rep == DMP([[QQ(1)], [QQ(1), QQ(0)]], QQ)
def test_Poly_from_expr():
raises(GeneratorsNeeded, lambda: Poly.from_expr(S(0)))
raises(GeneratorsNeeded, lambda: Poly.from_expr(S(7)))
F3 = FF(3)
assert Poly.from_expr(x + 5, domain=F3).rep == DMP([F3(1), F3(2)], F3)
assert Poly.from_expr(y + 5, domain=F3).rep == DMP([F3(1), F3(2)], F3)
assert Poly.from_expr(x + 5, x, domain=F3).rep == DMP([F3(1), F3(2)], F3)
assert Poly.from_expr(y + 5, y, domain=F3).rep == DMP([F3(1), F3(2)], F3)
assert Poly.from_expr(x + y, domain=F3).rep == DMP([[F3(1)], [F3(1), F3(0)]], F3)
assert Poly.from_expr(x + y, x, y, domain=F3).rep == DMP([[F3(1)], [F3(1), F3(0)]], F3)
assert Poly.from_expr(x + 5).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(y + 5).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(x + 5, x).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(y + 5, y).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(x + 5, domain=ZZ).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(y + 5, domain=ZZ).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(x + 5, x, domain=ZZ).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(y + 5, y, domain=ZZ).rep == DMP([1, 5], ZZ)
assert Poly.from_expr(x + 5, x, y, domain=ZZ).rep == DMP([[1], [5]], ZZ)
assert Poly.from_expr(y + 5, x, y, domain=ZZ).rep == DMP([[1, 5]], ZZ)
def test_Poly__new__():
raises(GeneratorsError, lambda: Poly(x + 1, x, x))
raises(GeneratorsError, lambda: Poly(x + y, x, y, domain=ZZ[x]))
raises(GeneratorsError, lambda: Poly(x + y, x, y, domain=ZZ[y]))
raises(OptionError, lambda: Poly(x, x, symmetric=True))
raises(OptionError, lambda: Poly(x + 2, x, modulus=3, domain=QQ))
raises(OptionError, lambda: Poly(x + 2, x, domain=ZZ, gaussian=True))
raises(OptionError, lambda: Poly(x + 2, x, modulus=3, gaussian=True))
raises(OptionError, lambda: Poly(x + 2, x, domain=ZZ, extension=[sqrt(3)]))
raises(OptionError, lambda: Poly(x + 2, x, modulus=3, extension=[sqrt(3)]))
raises(OptionError, lambda: Poly(x + 2, x, domain=ZZ, extension=True))
raises(OptionError, lambda: Poly(x + 2, x, modulus=3, extension=True))
raises(OptionError, lambda: Poly(x + 2, x, domain=ZZ, greedy=True))
raises(OptionError, lambda: Poly(x + 2, x, domain=QQ, field=True))
raises(OptionError, lambda: Poly(x + 2, x, domain=ZZ, greedy=False))
raises(OptionError, lambda: Poly(x + 2, x, domain=QQ, field=False))
raises(NotImplementedError, lambda: Poly(x + 1, x, modulus=3, order='grlex'))
raises(NotImplementedError, lambda: Poly(x + 1, x, order='grlex'))
raises(GeneratorsNeeded, lambda: Poly({1: 2, 0: 1}))
raises(GeneratorsNeeded, lambda: Poly([2, 1]))
raises(GeneratorsNeeded, lambda: Poly((2, 1)))
raises(GeneratorsNeeded, lambda: Poly(1))
f = a*x**2 + b*x + c
assert Poly({2: a, 1: b, 0: c}, x) == f
assert Poly(iter([a, b, c]), x) == f
assert Poly([a, b, c], x) == f
assert Poly((a, b, c), x) == f
f = Poly({}, x, y, z)
assert f.gens == (x, y, z) and f.as_expr() == 0
assert Poly(Poly(a*x + b*y, x, y), x) == Poly(a*x + b*y, x)
assert Poly(3*x**2 + 2*x + 1, domain='ZZ').all_coeffs() == [3, 2, 1]
assert Poly(3*x**2 + 2*x + 1, domain='QQ').all_coeffs() == [3, 2, 1]
assert Poly(3*x**2 + 2*x + 1, domain='RR').all_coeffs() == [3.0, 2.0, 1.0]
raises(CoercionFailed, lambda: Poly(3*x**2/5 + 2*x/5 + 1, domain='ZZ'))
assert Poly(
3*x**2/5 + 2*x/5 + 1, domain='QQ').all_coeffs() == [S(3)/5, S(2)/5, 1]
assert _epsilon_eq(
Poly(3*x**2/5 + 2*x/5 + 1, domain='RR').all_coeffs(), [0.6, 0.4, 1.0])
assert Poly(3.0*x**2 + 2.0*x + 1, domain='ZZ').all_coeffs() == [3, 2, 1]
assert Poly(3.0*x**2 + 2.0*x + 1, domain='QQ').all_coeffs() == [3, 2, 1]
assert Poly(
3.0*x**2 + 2.0*x + 1, domain='RR').all_coeffs() == [3.0, 2.0, 1.0]
raises(CoercionFailed, lambda: Poly(3.1*x**2 + 2.1*x + 1, domain='ZZ'))
assert Poly(3.1*x**2 + 2.1*x + 1, domain='QQ').all_coeffs() == [S(31)/10, S(21)/10, 1]
assert Poly(3.1*x**2 + 2.1*x + 1, domain='RR').all_coeffs() == [3.1, 2.1, 1.0]
assert Poly({(2, 1): 1, (1, 2): 2, (1, 1): 3}, x, y) == \
Poly(x**2*y + 2*x*y**2 + 3*x*y, x, y)
assert Poly(x**2 + 1, extension=I).get_domain() == QQ.algebraic_field(I)
f = 3*x**5 - x**4 + x**3 - x** 2 + 65538
assert Poly(f, x, modulus=65537, symmetric=True) == \
Poly(3*x**5 - x**4 + x**3 - x** 2 + 1, x, modulus=65537,
symmetric=True)
assert Poly(f, x, modulus=65537, symmetric=False) == \
Poly(3*x**5 + 65536*x**4 + x**3 + 65536*x** 2 + 1, x,
modulus=65537, symmetric=False)
assert isinstance(Poly(x**2 + x + 1.0).get_domain(), RealField)
def test_Poly__args():
assert Poly(x**2 + 1).args == (x**2 + 1,)
def test_Poly__gens():
assert Poly((x - p)*(x - q), x).gens == (x,)
assert Poly((x - p)*(x - q), p).gens == (p,)
assert Poly((x - p)*(x - q), q).gens == (q,)
assert Poly((x - p)*(x - q), x, p).gens == (x, p)
assert Poly((x - p)*(x - q), x, q).gens == (x, q)
assert Poly((x - p)*(x - q), x, p, q).gens == (x, p, q)
assert Poly((x - p)*(x - q), p, x, q).gens == (p, x, q)
assert Poly((x - p)*(x - q), p, q, x).gens == (p, q, x)
assert Poly((x - p)*(x - q)).gens == (x, p, q)
assert Poly((x - p)*(x - q), sort='x > p > q').gens == (x, p, q)
assert Poly((x - p)*(x - q), sort='p > x > q').gens == (p, x, q)
assert Poly((x - p)*(x - q), sort='p > q > x').gens == (p, q, x)
assert Poly((x - p)*(x - q), x, p, q, sort='p > q > x').gens == (x, p, q)
assert Poly((x - p)*(x - q), wrt='x').gens == (x, p, q)
assert Poly((x - p)*(x - q), wrt='p').gens == (p, x, q)
assert Poly((x - p)*(x - q), wrt='q').gens == (q, x, p)
assert Poly((x - p)*(x - q), wrt=x).gens == (x, p, q)
assert Poly((x - p)*(x - q), wrt=p).gens == (p, x, q)
assert Poly((x - p)*(x - q), wrt=q).gens == (q, x, p)
assert Poly((x - p)*(x - q), x, p, q, wrt='p').gens == (x, p, q)
assert Poly((x - p)*(x - q), wrt='p', sort='q > x').gens == (p, q, x)
assert Poly((x - p)*(x - q), wrt='q', sort='p > x').gens == (q, p, x)
def test_Poly_zero():
assert Poly(x).zero == Poly(0, x, domain=ZZ)
assert Poly(x/2).zero == Poly(0, x, domain=QQ)
def test_Poly_one():
assert Poly(x).one == Poly(1, x, domain=ZZ)
assert Poly(x/2).one == Poly(1, x, domain=QQ)
def test_Poly__unify():
raises(UnificationFailed, lambda: Poly(x)._unify(y))
F3 = FF(3)
F5 = FF(5)
assert Poly(x, x, modulus=3)._unify(Poly(y, y, modulus=3))[2:] == (
DMP([[F3(1)], []], F3), DMP([[F3(1), F3(0)]], F3))
assert Poly(x, x, modulus=3)._unify(Poly(y, y, modulus=5))[2:] == (
DMP([[F5(1)], []], F5), DMP([[F5(1), F5(0)]], F5))
assert Poly(y, x, y)._unify(Poly(x, x, modulus=3))[2:] == (DMP([[F3(1), F3(0)]], F3), DMP([[F3(1)], []], F3))
assert Poly(x, x, modulus=3)._unify(Poly(y, x, y))[2:] == (DMP([[F3(1)], []], F3), DMP([[F3(1), F3(0)]], F3))
assert Poly(x + 1, x)._unify(Poly(x + 2, x))[2:] == (DMP([1, 1], ZZ), DMP([1, 2], ZZ))
assert Poly(x + 1, x, domain='QQ')._unify(Poly(x + 2, x))[2:] == (DMP([1, 1], QQ), DMP([1, 2], QQ))
assert Poly(x + 1, x)._unify(Poly(x + 2, x, domain='QQ'))[2:] == (DMP([1, 1], QQ), DMP([1, 2], QQ))
assert Poly(x + 1, x)._unify(Poly(x + 2, x, y))[2:] == (DMP([[1], [1]], ZZ), DMP([[1], [2]], ZZ))
assert Poly(x + 1, x, domain='QQ')._unify(Poly(x + 2, x, y))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x)._unify(Poly(x + 2, x, y, domain='QQ'))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, x))[2:] == (DMP([[1], [1]], ZZ), DMP([[1], [2]], ZZ))
assert Poly(x + 1, x, y, domain='QQ')._unify(Poly(x + 2, x))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, x, domain='QQ'))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, x, y))[2:] == (DMP([[1], [1]], ZZ), DMP([[1], [2]], ZZ))
assert Poly(x + 1, x, y, domain='QQ')._unify(Poly(x + 2, x, y))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, x, y, domain='QQ'))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x)._unify(Poly(x + 2, y, x))[2:] == (DMP([[1, 1]], ZZ), DMP([[1, 2]], ZZ))
assert Poly(x + 1, x, domain='QQ')._unify(Poly(x + 2, y, x))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
assert Poly(x + 1, x)._unify(Poly(x + 2, y, x, domain='QQ'))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
assert Poly(x + 1, y, x)._unify(Poly(x + 2, x))[2:] == (DMP([[1, 1]], ZZ), DMP([[1, 2]], ZZ))
assert Poly(x + 1, y, x, domain='QQ')._unify(Poly(x + 2, x))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
assert Poly(x + 1, y, x)._unify(Poly(x + 2, x, domain='QQ'))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, y, x))[2:] == (DMP([[1], [1]], ZZ), DMP([[1], [2]], ZZ))
assert Poly(x + 1, x, y, domain='QQ')._unify(Poly(x + 2, y, x))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, x, y)._unify(Poly(x + 2, y, x, domain='QQ'))[2:] == (DMP([[1], [1]], QQ), DMP([[1], [2]], QQ))
assert Poly(x + 1, y, x)._unify(Poly(x + 2, x, y))[2:] == (DMP([[1, 1]], ZZ), DMP([[1, 2]], ZZ))
assert Poly(x + 1, y, x, domain='QQ')._unify(Poly(x + 2, x, y))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
assert Poly(x + 1, y, x)._unify(Poly(x + 2, x, y, domain='QQ'))[2:] == (DMP([[1, 1]], QQ), DMP([[1, 2]], QQ))
F, A, B = field("a,b", ZZ)
assert Poly(a*x, x, domain='ZZ[a]')._unify(Poly(a*b*x, x, domain='ZZ(a,b)'))[2:] == \
(DMP([A, F(0)], F.to_domain()), DMP([A*B, F(0)], F.to_domain()))
assert Poly(a*x, x, domain='ZZ(a)')._unify(Poly(a*b*x, x, domain='ZZ(a,b)'))[2:] == \
(DMP([A, F(0)], F.to_domain()), DMP([A*B, F(0)], F.to_domain()))
raises(CoercionFailed, lambda: Poly(Poly(x**2 + x**2*z, y, field=True), domain='ZZ(x)'))
f = Poly(t**2 + t/3 + x, t, domain='QQ(x)')
g = Poly(t**2 + t/3 + x, t, domain='QQ[x]')
assert f._unify(g)[2:] == (f.rep, f.rep)
def test_Poly_free_symbols():
assert Poly(x**2 + 1).free_symbols == {x}
assert Poly(x**2 + y*z).free_symbols == {x, y, z}
assert Poly(x**2 + y*z, x).free_symbols == {x, y, z}
assert Poly(x**2 + sin(y*z)).free_symbols == {x, y, z}
assert Poly(x**2 + sin(y*z), x).free_symbols == {x, y, z}
assert Poly(x**2 + sin(y*z), x, domain=EX).free_symbols == {x, y, z}
assert Poly(1 + x + x**2, x, y, z).free_symbols == {x}
assert Poly(x + sin(y), z).free_symbols == {x, y}
def test_PurePoly_free_symbols():
assert PurePoly(x**2 + 1).free_symbols == set([])
assert PurePoly(x**2 + y*z).free_symbols == set([])
assert PurePoly(x**2 + y*z, x).free_symbols == {y, z}
assert PurePoly(x**2 + sin(y*z)).free_symbols == set([])
assert PurePoly(x**2 + sin(y*z), x).free_symbols == {y, z}
assert PurePoly(x**2 + sin(y*z), x, domain=EX).free_symbols == {y, z}
def test_Poly__eq__():
assert (Poly(x, x) == Poly(x, x)) is True
assert (Poly(x, x, domain=QQ) == Poly(x, x)) is True
assert (Poly(x, x) == Poly(x, x, domain=QQ)) is True
assert (Poly(x, x, domain=ZZ[a]) == Poly(x, x)) is True
assert (Poly(x, x) == Poly(x, x, domain=ZZ[a])) is True
assert (Poly(x*y, x, y) == Poly(x, x)) is False
assert (Poly(x, x, y) == Poly(x, x)) is False
assert (Poly(x, x) == Poly(x, x, y)) is False
assert (Poly(x**2 + 1, x) == Poly(y**2 + 1, y)) is False
assert (Poly(y**2 + 1, y) == Poly(x**2 + 1, x)) is False
f = Poly(x, x, domain=ZZ)
g = Poly(x, x, domain=QQ)
assert f.eq(g) is True
assert f.ne(g) is False
assert f.eq(g, strict=True) is False
assert f.ne(g, strict=True) is True
t0 = Symbol('t0')
f = Poly((t0/2 + x**2)*t**2 - x**2*t, t, domain='QQ[x,t0]')
g = Poly((t0/2 + x**2)*t**2 - x**2*t, t, domain='ZZ(x,t0)')
assert (f == g) is True
def test_PurePoly__eq__():
assert (PurePoly(x, x) == PurePoly(x, x)) is True
assert (PurePoly(x, x, domain=QQ) == PurePoly(x, x)) is True
assert (PurePoly(x, x) == PurePoly(x, x, domain=QQ)) is True
assert (PurePoly(x, x, domain=ZZ[a]) == PurePoly(x, x)) is True
assert (PurePoly(x, x) == PurePoly(x, x, domain=ZZ[a])) is True
assert (PurePoly(x*y, x, y) == PurePoly(x, x)) is False
assert (PurePoly(x, x, y) == PurePoly(x, x)) is False
assert (PurePoly(x, x) == PurePoly(x, x, y)) is False
assert (PurePoly(x**2 + 1, x) == PurePoly(y**2 + 1, y)) is True
assert (PurePoly(y**2 + 1, y) == PurePoly(x**2 + 1, x)) is True
f = PurePoly(x, x, domain=ZZ)
g = PurePoly(x, x, domain=QQ)
assert f.eq(g) is True
assert f.ne(g) is False
assert f.eq(g, strict=True) is False
assert f.ne(g, strict=True) is True
f = PurePoly(x, x, domain=ZZ)
g = PurePoly(y, y, domain=QQ)
assert f.eq(g) is True
assert f.ne(g) is False
assert f.eq(g, strict=True) is False
assert f.ne(g, strict=True) is True
def test_PurePoly_Poly():
assert isinstance(PurePoly(Poly(x**2 + 1)), PurePoly) is True
assert isinstance(Poly(PurePoly(x**2 + 1)), Poly) is True
def test_Poly_get_domain():
assert Poly(2*x).get_domain() == ZZ
assert Poly(2*x, domain='ZZ').get_domain() == ZZ
assert Poly(2*x, domain='QQ').get_domain() == QQ
assert Poly(x/2).get_domain() == QQ
raises(CoercionFailed, lambda: Poly(x/2, domain='ZZ'))
assert Poly(x/2, domain='QQ').get_domain() == QQ
assert isinstance(Poly(0.2*x).get_domain(), RealField)
def test_Poly_set_domain():
assert Poly(2*x + 1).set_domain(ZZ) == Poly(2*x + 1)
assert Poly(2*x + 1).set_domain('ZZ') == Poly(2*x + 1)
assert Poly(2*x + 1).set_domain(QQ) == Poly(2*x + 1, domain='QQ')
assert Poly(2*x + 1).set_domain('QQ') == Poly(2*x + 1, domain='QQ')
assert Poly(S(2)/10*x + S(1)/10).set_domain('RR') == Poly(0.2*x + 0.1)
assert Poly(0.2*x + 0.1).set_domain('QQ') == Poly(S(2)/10*x + S(1)/10)
raises(CoercionFailed, lambda: Poly(x/2 + 1).set_domain(ZZ))
raises(CoercionFailed, lambda: Poly(x + 1, modulus=2).set_domain(QQ))
raises(GeneratorsError, lambda: Poly(x*y, x, y).set_domain(ZZ[y]))
def test_Poly_get_modulus():
assert Poly(x**2 + 1, modulus=2).get_modulus() == 2
raises(PolynomialError, lambda: Poly(x**2 + 1).get_modulus())
def test_Poly_set_modulus():
assert Poly(
x**2 + 1, modulus=2).set_modulus(7) == Poly(x**2 + 1, modulus=7)
assert Poly(
x**2 + 5, modulus=7).set_modulus(2) == Poly(x**2 + 1, modulus=2)
assert Poly(x**2 + 1).set_modulus(2) == Poly(x**2 + 1, modulus=2)
raises(CoercionFailed, lambda: Poly(x/2 + 1).set_modulus(2))
def test_Poly_add_ground():
assert Poly(x + 1).add_ground(2) == Poly(x + 3)
def test_Poly_sub_ground():
assert Poly(x + 1).sub_ground(2) == Poly(x - 1)
def test_Poly_mul_ground():
assert Poly(x + 1).mul_ground(2) == Poly(2*x + 2)
def test_Poly_quo_ground():
assert Poly(2*x + 4).quo_ground(2) == Poly(x + 2)
assert Poly(2*x + 3).quo_ground(2) == Poly(x + 1)
def test_Poly_exquo_ground():
assert Poly(2*x + 4).exquo_ground(2) == Poly(x + 2)
raises(ExactQuotientFailed, lambda: Poly(2*x + 3).exquo_ground(2))
def test_Poly_abs():
assert Poly(-x + 1, x).abs() == abs(Poly(-x + 1, x)) == Poly(x + 1, x)
def test_Poly_neg():
assert Poly(-x + 1, x).neg() == -Poly(-x + 1, x) == Poly(x - 1, x)
def test_Poly_add():
assert Poly(0, x).add(Poly(0, x)) == Poly(0, x)
assert Poly(0, x) + Poly(0, x) == Poly(0, x)
assert Poly(1, x).add(Poly(0, x)) == Poly(1, x)
assert Poly(1, x, y) + Poly(0, x) == Poly(1, x, y)
assert Poly(0, x).add(Poly(1, x, y)) == Poly(1, x, y)
assert Poly(0, x, y) + Poly(1, x, y) == Poly(1, x, y)
assert Poly(1, x) + x == Poly(x + 1, x)
assert Poly(1, x) + sin(x) == 1 + sin(x)
assert Poly(x, x) + 1 == Poly(x + 1, x)
assert 1 + Poly(x, x) == Poly(x + 1, x)
def test_Poly_sub():
assert Poly(0, x).sub(Poly(0, x)) == Poly(0, x)
assert Poly(0, x) - Poly(0, x) == Poly(0, x)
assert Poly(1, x).sub(Poly(0, x)) == Poly(1, x)
assert Poly(1, x, y) - Poly(0, x) == Poly(1, x, y)
assert Poly(0, x).sub(Poly(1, x, y)) == Poly(-1, x, y)
assert Poly(0, x, y) - Poly(1, x, y) == Poly(-1, x, y)
assert Poly(1, x) - x == Poly(1 - x, x)
assert Poly(1, x) - sin(x) == 1 - sin(x)
assert Poly(x, x) - 1 == Poly(x - 1, x)
assert 1 - Poly(x, x) == Poly(1 - x, x)
def test_Poly_mul():
assert Poly(0, x).mul(Poly(0, x)) == Poly(0, x)
assert Poly(0, x) * Poly(0, x) == Poly(0, x)
assert Poly(2, x).mul(Poly(4, x)) == Poly(8, x)
assert Poly(2, x, y) * Poly(4, x) == Poly(8, x, y)
assert Poly(4, x).mul(Poly(2, x, y)) == Poly(8, x, y)
assert Poly(4, x, y) * Poly(2, x, y) == Poly(8, x, y)
assert Poly(1, x) * x == Poly(x, x)
assert Poly(1, x) * sin(x) == sin(x)
assert Poly(x, x) * 2 == Poly(2*x, x)
assert 2 * Poly(x, x) == Poly(2*x, x)
def test_issue_13079():
assert Poly(x)*x == Poly(x**2, x, domain='ZZ')
assert x*Poly(x) == Poly(x**2, x, domain='ZZ')
assert -2*Poly(x) == Poly(-2*x, x, domain='ZZ')
assert S(-2)*Poly(x) == Poly(-2*x, x, domain='ZZ')
assert Poly(x)*S(-2) == Poly(-2*x, x, domain='ZZ')
def test_Poly_sqr():
assert Poly(x*y, x, y).sqr() == Poly(x**2*y**2, x, y)
def test_Poly_pow():
assert Poly(x, x).pow(10) == Poly(x**10, x)
assert Poly(x, x).pow(Integer(10)) == Poly(x**10, x)
assert Poly(2*y, x, y).pow(4) == Poly(16*y**4, x, y)
assert Poly(2*y, x, y).pow(Integer(4)) == Poly(16*y**4, x, y)
assert Poly(7*x*y, x, y)**3 == Poly(343*x**3*y**3, x, y)
assert Poly(x*y + 1, x, y)**(-1) == (x*y + 1)**(-1)
assert Poly(x*y + 1, x, y)**x == (x*y + 1)**x
def test_Poly_divmod():
f, g = Poly(x**2), Poly(x)
q, r = g, Poly(0, x)
assert divmod(f, g) == (q, r)
assert f // g == q
assert f % g == r
assert divmod(f, x) == (q, r)
assert f // x == q
assert f % x == r
q, r = Poly(0, x), Poly(2, x)
assert divmod(2, g) == (q, r)
assert 2 // g == q
assert 2 % g == r
assert Poly(x)/Poly(x) == 1
assert Poly(x**2)/Poly(x) == x
assert Poly(x)/Poly(x**2) == 1/x
def test_Poly_eq_ne():
assert (Poly(x + y, x, y) == Poly(x + y, x, y)) is True
assert (Poly(x + y, x) == Poly(x + y, x, y)) is False
assert (Poly(x + y, x, y) == Poly(x + y, x)) is False
assert (Poly(x + y, x) == Poly(x + y, x)) is True
assert (Poly(x + y, y) == Poly(x + y, y)) is True
assert (Poly(x + y, x, y) == x + y) is True
assert (Poly(x + y, x) == x + y) is True
assert (Poly(x + y, x, y) == x + y) is True
assert (Poly(x + y, x) == x + y) is True
assert (Poly(x + y, y) == x + y) is True
assert (Poly(x + y, x, y) != Poly(x + y, x, y)) is False
assert (Poly(x + y, x) != Poly(x + y, x, y)) is True
assert (Poly(x + y, x, y) != Poly(x + y, x)) is True
assert (Poly(x + y, x) != Poly(x + y, x)) is False
assert (Poly(x + y, y) != Poly(x + y, y)) is False
assert (Poly(x + y, x, y) != x + y) is False
assert (Poly(x + y, x) != x + y) is False
assert (Poly(x + y, x, y) != x + y) is False
assert (Poly(x + y, x) != x + y) is False
assert (Poly(x + y, y) != x + y) is False
assert (Poly(x, x) == sin(x)) is False
assert (Poly(x, x) != sin(x)) is True
def test_Poly_nonzero():
assert not bool(Poly(0, x)) is True
assert not bool(Poly(1, x)) is False
def test_Poly_properties():
assert Poly(0, x).is_zero is True
assert Poly(1, x).is_zero is False
assert Poly(1, x).is_one is True
assert Poly(2, x).is_one is False
assert Poly(x - 1, x).is_sqf is True
assert Poly((x - 1)**2, x).is_sqf is False
assert Poly(x - 1, x).is_monic is True
assert Poly(2*x - 1, x).is_monic is False
assert Poly(3*x + 2, x).is_primitive is True
assert Poly(4*x + 2, x).is_primitive is False
assert Poly(1, x).is_ground is True
assert Poly(x, x).is_ground is False
assert Poly(x + y + z + 1).is_linear is True
assert Poly(x*y*z + 1).is_linear is False
assert Poly(x*y + z + 1).is_quadratic is True
assert Poly(x*y*z + 1).is_quadratic is False
assert Poly(x*y).is_monomial is True
assert Poly(x*y + 1).is_monomial is False
assert Poly(x**2 + x*y).is_homogeneous is True
assert Poly(x**3 + x*y).is_homogeneous is False
assert Poly(x).is_univariate is True
assert Poly(x*y).is_univariate is False
assert Poly(x*y).is_multivariate is True
assert Poly(x).is_multivariate is False
assert Poly(
x**16 + x**14 - x**10 + x**8 - x**6 + x**2 + 1).is_cyclotomic is False
assert Poly(
x**16 + x**14 - x**10 - x**8 - x**6 + x**2 + 1).is_cyclotomic is True
def test_Poly_is_irreducible():
assert Poly(x**2 + x + 1).is_irreducible is True
assert Poly(x**2 + 2*x + 1).is_irreducible is False
assert Poly(7*x + 3, modulus=11).is_irreducible is True
assert Poly(7*x**2 + 3*x + 1, modulus=11).is_irreducible is False
def test_Poly_subs():
assert Poly(x + 1).subs(x, 0) == 1
assert Poly(x + 1).subs(x, x) == Poly(x + 1)
assert Poly(x + 1).subs(x, y) == Poly(y + 1)
assert Poly(x*y, x).subs(y, x) == x**2
assert Poly(x*y, x).subs(x, y) == y**2
def test_Poly_replace():
assert Poly(x + 1).replace(x) == Poly(x + 1)
assert Poly(x + 1).replace(y) == Poly(y + 1)
raises(PolynomialError, lambda: Poly(x + y).replace(z))
assert Poly(x + 1).replace(x, x) == Poly(x + 1)
assert Poly(x + 1).replace(x, y) == Poly(y + 1)
assert Poly(x + y).replace(x, x) == Poly(x + y)
assert Poly(x + y).replace(x, z) == Poly(z + y, z, y)
assert Poly(x + y).replace(y, y) == Poly(x + y)
assert Poly(x + y).replace(y, z) == Poly(x + z, x, z)
assert Poly(x + y).replace(z, t) == Poly(x + y)
raises(PolynomialError, lambda: Poly(x + y).replace(x, y))
assert Poly(x + y, x).replace(x, z) == Poly(z + y, z)
assert Poly(x + y, y).replace(y, z) == Poly(x + z, z)
raises(PolynomialError, lambda: Poly(x + y, x).replace(x, y))
raises(PolynomialError, lambda: Poly(x + y, y).replace(y, x))
def test_Poly_reorder():
raises(PolynomialError, lambda: Poly(x + y).reorder(x, z))
assert Poly(x + y, x, y).reorder(x, y) == Poly(x + y, x, y)
assert Poly(x + y, x, y).reorder(y, x) == Poly(x + y, y, x)
assert Poly(x + y, y, x).reorder(x, y) == Poly(x + y, x, y)
assert Poly(x + y, y, x).reorder(y, x) == Poly(x + y, y, x)
assert Poly(x + y, x, y).reorder(wrt=x) == Poly(x + y, x, y)
assert Poly(x + y, x, y).reorder(wrt=y) == Poly(x + y, y, x)
def test_Poly_ltrim():
f = Poly(y**2 + y*z**2, x, y, z).ltrim(y)
assert f.as_expr() == y**2 + y*z**2 and f.gens == (y, z)
assert Poly(x*y - x, z, x, y).ltrim(1) == Poly(x*y - x, x, y)
raises(PolynomialError, lambda: Poly(x*y**2 + y**2, x, y).ltrim(y))
raises(PolynomialError, lambda: Poly(x*y - x, x, y).ltrim(-1))
def test_Poly_has_only_gens():
assert Poly(x*y + 1, x, y, z).has_only_gens(x, y) is True
assert Poly(x*y + z, x, y, z).has_only_gens(x, y) is False
raises(GeneratorsError, lambda: Poly(x*y**2 + y**2, x, y).has_only_gens(t))
def test_Poly_to_ring():
assert Poly(2*x + 1, domain='ZZ').to_ring() == Poly(2*x + 1, domain='ZZ')
assert Poly(2*x + 1, domain='QQ').to_ring() == Poly(2*x + 1, domain='ZZ')
raises(CoercionFailed, lambda: Poly(x/2 + 1).to_ring())
raises(DomainError, lambda: Poly(2*x + 1, modulus=3).to_ring())
def test_Poly_to_field():
assert Poly(2*x + 1, domain='ZZ').to_field() == Poly(2*x + 1, domain='QQ')
assert Poly(2*x + 1, domain='QQ').to_field() == Poly(2*x + 1, domain='QQ')
assert Poly(x/2 + 1, domain='QQ').to_field() == Poly(x/2 + 1, domain='QQ')
assert Poly(2*x + 1, modulus=3).to_field() == Poly(2*x + 1, modulus=3)
assert Poly(2.0*x + 1.0).to_field() == Poly(2.0*x + 1.0)
def test_Poly_to_exact():
assert Poly(2*x).to_exact() == Poly(2*x)
assert Poly(x/2).to_exact() == Poly(x/2)
assert Poly(0.1*x).to_exact() == Poly(x/10)
def test_Poly_retract():
f = Poly(x**2 + 1, x, domain=QQ[y])
assert f.retract() == Poly(x**2 + 1, x, domain='ZZ')
assert f.retract(field=True) == Poly(x**2 + 1, x, domain='QQ')
assert Poly(0, x, y).retract() == Poly(0, x, y)
def test_Poly_slice():
f = Poly(x**3 + 2*x**2 + 3*x + 4)
assert f.slice(0, 0) == Poly(0, x)
assert f.slice(0, 1) == Poly(4, x)
assert f.slice(0, 2) == Poly(3*x + 4, x)
assert f.slice(0, 3) == Poly(2*x**2 + 3*x + 4, x)
assert f.slice(0, 4) == Poly(x**3 + 2*x**2 + 3*x + 4, x)
assert f.slice(x, 0, 0) == Poly(0, x)
assert f.slice(x, 0, 1) == Poly(4, x)
assert f.slice(x, 0, 2) == Poly(3*x + 4, x)
assert f.slice(x, 0, 3) == Poly(2*x**2 + 3*x + 4, x)
assert f.slice(x, 0, 4) == Poly(x**3 + 2*x**2 + 3*x + 4, x)
def test_Poly_coeffs():
assert Poly(0, x).coeffs() == [0]
assert Poly(1, x).coeffs() == [1]
assert Poly(2*x + 1, x).coeffs() == [2, 1]
assert Poly(7*x**2 + 2*x + 1, x).coeffs() == [7, 2, 1]
assert Poly(7*x**4 + 2*x + 1, x).coeffs() == [7, 2, 1]
assert Poly(x*y**7 + 2*x**2*y**3).coeffs('lex') == [2, 1]
assert Poly(x*y**7 + 2*x**2*y**3).coeffs('grlex') == [1, 2]
def test_Poly_monoms():
assert Poly(0, x).monoms() == [(0,)]
assert Poly(1, x).monoms() == [(0,)]
assert Poly(2*x + 1, x).monoms() == [(1,), (0,)]
assert Poly(7*x**2 + 2*x + 1, x).monoms() == [(2,), (1,), (0,)]
assert Poly(7*x**4 + 2*x + 1, x).monoms() == [(4,), (1,), (0,)]
assert Poly(x*y**7 + 2*x**2*y**3).monoms('lex') == [(2, 3), (1, 7)]
assert Poly(x*y**7 + 2*x**2*y**3).monoms('grlex') == [(1, 7), (2, 3)]
def test_Poly_terms():
assert Poly(0, x).terms() == [((0,), 0)]
assert Poly(1, x).terms() == [((0,), 1)]
assert Poly(2*x + 1, x).terms() == [((1,), 2), ((0,), 1)]
assert Poly(7*x**2 + 2*x + 1, x).terms() == [((2,), 7), ((1,), 2), ((0,), 1)]
assert Poly(7*x**4 + 2*x + 1, x).terms() == [((4,), 7), ((1,), 2), ((0,), 1)]
assert Poly(
x*y**7 + 2*x**2*y**3).terms('lex') == [((2, 3), 2), ((1, 7), 1)]
assert Poly(
x*y**7 + 2*x**2*y**3).terms('grlex') == [((1, 7), 1), ((2, 3), 2)]
def test_Poly_all_coeffs():
assert Poly(0, x).all_coeffs() == [0]
assert Poly(1, x).all_coeffs() == [1]
assert Poly(2*x + 1, x).all_coeffs() == [2, 1]
assert Poly(7*x**2 + 2*x + 1, x).all_coeffs() == [7, 2, 1]
assert Poly(7*x**4 + 2*x + 1, x).all_coeffs() == [7, 0, 0, 2, 1]
def test_Poly_all_monoms():
assert Poly(0, x).all_monoms() == [(0,)]
assert Poly(1, x).all_monoms() == [(0,)]
assert Poly(2*x + 1, x).all_monoms() == [(1,), (0,)]
assert Poly(7*x**2 + 2*x + 1, x).all_monoms() == [(2,), (1,), (0,)]
assert Poly(7*x**4 + 2*x + 1, x).all_monoms() == [(4,), (3,), (2,), (1,), (0,)]
def test_Poly_all_terms():
assert Poly(0, x).all_terms() == [((0,), 0)]
assert Poly(1, x).all_terms() == [((0,), 1)]
assert Poly(2*x + 1, x).all_terms() == [((1,), 2), ((0,), 1)]
assert Poly(7*x**2 + 2*x + 1, x).all_terms() == \
[((2,), 7), ((1,), 2), ((0,), 1)]
assert Poly(7*x**4 + 2*x + 1, x).all_terms() == \
[((4,), 7), ((3,), 0), ((2,), 0), ((1,), 2), ((0,), 1)]
def test_Poly_termwise():
f = Poly(x**2 + 20*x + 400)
g = Poly(x**2 + 2*x + 4)
def func(monom, coeff):
(k,) = monom
return coeff//10**(2 - k)
assert f.termwise(func) == g
def func(monom, coeff):
(k,) = monom
return (k,), coeff//10**(2 - k)
assert f.termwise(func) == g
def test_Poly_length():
assert Poly(0, x).length() == 0
assert Poly(1, x).length() == 1
assert Poly(x, x).length() == 1
assert Poly(x + 1, x).length() == 2
assert Poly(x**2 + 1, x).length() == 2
assert Poly(x**2 + x + 1, x).length() == 3
def test_Poly_as_dict():
assert Poly(0, x).as_dict() == {}
assert Poly(0, x, y, z).as_dict() == {}
assert Poly(1, x).as_dict() == {(0,): 1}
assert Poly(1, x, y, z).as_dict() == {(0, 0, 0): 1}
assert Poly(x**2 + 3, x).as_dict() == {(2,): 1, (0,): 3}
assert Poly(x**2 + 3, x, y, z).as_dict() == {(2, 0, 0): 1, (0, 0, 0): 3}
assert Poly(3*x**2*y*z**3 + 4*x*y + 5*x*z).as_dict() == {(2, 1, 3): 3,
(1, 1, 0): 4, (1, 0, 1): 5}
def test_Poly_as_expr():
assert Poly(0, x).as_expr() == 0
assert Poly(0, x, y, z).as_expr() == 0
assert Poly(1, x).as_expr() == 1
assert Poly(1, x, y, z).as_expr() == 1
assert Poly(x**2 + 3, x).as_expr() == x**2 + 3
assert Poly(x**2 + 3, x, y, z).as_expr() == x**2 + 3
assert Poly(
3*x**2*y*z**3 + 4*x*y + 5*x*z).as_expr() == 3*x**2*y*z**3 + 4*x*y + 5*x*z
f = Poly(x**2 + 2*x*y**2 - y, x, y)
assert f.as_expr() == -y + x**2 + 2*x*y**2
assert f.as_expr({x: 5}) == 25 - y + 10*y**2
assert f.as_expr({y: 6}) == -6 + 72*x + x**2
assert f.as_expr({x: 5, y: 6}) == 379
assert f.as_expr(5, 6) == 379
raises(GeneratorsError, lambda: f.as_expr({z: 7}))
def test_Poly_lift():
assert Poly(x**4 - I*x + 17*I, x, gaussian=True).lift() == \
Poly(x**16 + 2*x**10 + 578*x**8 + x**4 - 578*x**2 + 83521,
x, domain='QQ')
def test_Poly_deflate():
assert Poly(0, x).deflate() == ((1,), Poly(0, x))
assert Poly(1, x).deflate() == ((1,), Poly(1, x))
assert Poly(x, x).deflate() == ((1,), Poly(x, x))
assert Poly(x**2, x).deflate() == ((2,), Poly(x, x))
assert Poly(x**17, x).deflate() == ((17,), Poly(x, x))
assert Poly(
x**2*y*z**11 + x**4*z**11).deflate() == ((2, 1, 11), Poly(x*y*z + x**2*z))
def test_Poly_inject():
f = Poly(x**2*y + x*y**3 + x*y + 1, x)
assert f.inject() == Poly(x**2*y + x*y**3 + x*y + 1, x, y)
assert f.inject(front=True) == Poly(y**3*x + y*x**2 + y*x + 1, y, x)
def test_Poly_eject():
f = Poly(x**2*y + x*y**3 + x*y + 1, x, y)
assert f.eject(x) == Poly(x*y**3 + (x**2 + x)*y + 1, y, domain='ZZ[x]')
assert f.eject(y) == Poly(y*x**2 + (y**3 + y)*x + 1, x, domain='ZZ[y]')
ex = x + y + z + t + w
g = Poly(ex, x, y, z, t, w)
assert g.eject(x) == Poly(ex, y, z, t, w, domain='ZZ[x]')
assert g.eject(x, y) == Poly(ex, z, t, w, domain='ZZ[x, y]')
assert g.eject(x, y, z) == Poly(ex, t, w, domain='ZZ[x, y, z]')
assert g.eject(w) == Poly(ex, x, y, z, t, domain='ZZ[w]')
assert g.eject(t, w) == Poly(ex, x, y, z, domain='ZZ[w, t]')
assert g.eject(z, t, w) == Poly(ex, x, y, domain='ZZ[w, t, z]')
raises(DomainError, lambda: Poly(x*y, x, y, domain=ZZ[z]).eject(y))
raises(NotImplementedError, lambda: Poly(x*y, x, y, z).eject(y))
def test_Poly_exclude():
assert Poly(x, x, y).exclude() == Poly(x, x)
assert Poly(x*y, x, y).exclude() == Poly(x*y, x, y)
assert Poly(1, x, y).exclude() == Poly(1, x, y)
def test_Poly__gen_to_level():
assert Poly(1, x, y)._gen_to_level(-2) == 0
assert Poly(1, x, y)._gen_to_level(-1) == 1
assert Poly(1, x, y)._gen_to_level( 0) == 0
assert Poly(1, x, y)._gen_to_level( 1) == 1
raises(PolynomialError, lambda: Poly(1, x, y)._gen_to_level(-3))
raises(PolynomialError, lambda: Poly(1, x, y)._gen_to_level( 2))
assert Poly(1, x, y)._gen_to_level(x) == 0
assert Poly(1, x, y)._gen_to_level(y) == 1
assert Poly(1, x, y)._gen_to_level('x') == 0
assert Poly(1, x, y)._gen_to_level('y') == 1
raises(PolynomialError, lambda: Poly(1, x, y)._gen_to_level(z))
raises(PolynomialError, lambda: Poly(1, x, y)._gen_to_level('z'))
def test_Poly_degree():
assert Poly(0, x).degree() == -oo
assert Poly(1, x).degree() == 0
assert Poly(x, x).degree() == 1
assert Poly(0, x).degree(gen=0) == -oo
assert Poly(1, x).degree(gen=0) == 0
assert Poly(x, x).degree(gen=0) == 1
assert Poly(0, x).degree(gen=x) == -oo
assert Poly(1, x).degree(gen=x) == 0
assert Poly(x, x).degree(gen=x) == 1
assert Poly(0, x).degree(gen='x') == -oo
assert Poly(1, x).degree(gen='x') == 0
assert Poly(x, x).degree(gen='x') == 1
raises(PolynomialError, lambda: Poly(1, x).degree(gen=1))
raises(PolynomialError, lambda: Poly(1, x).degree(gen=y))
raises(PolynomialError, lambda: Poly(1, x).degree(gen='y'))
assert Poly(1, x, y).degree() == 0
assert Poly(2*y, x, y).degree() == 0
assert Poly(x*y, x, y).degree() == 1
assert Poly(1, x, y).degree(gen=x) == 0
assert Poly(2*y, x, y).degree(gen=x) == 0
assert Poly(x*y, x, y).degree(gen=x) == 1
assert Poly(1, x, y).degree(gen=y) == 0
assert Poly(2*y, x, y).degree(gen=y) == 1
assert Poly(x*y, x, y).degree(gen=y) == 1
assert degree(0, x) == -oo
assert degree(1, x) == 0
assert degree(x, x) == 1
assert degree(x*y**2, x) == 1
assert degree(x*y**2, y) == 2
assert degree(x*y**2, z) == 0
assert degree(pi) == 1
raises(TypeError, lambda: degree(y**2 + x**3))
raises(TypeError, lambda: degree(y**2 + x**3, 1))
raises(PolynomialError, lambda: degree(x, 1.1))
raises(PolynomialError, lambda: degree(x**2/(x**3 + 1), x))
assert degree(Poly(0,x),z) == -oo
assert degree(Poly(1,x),z) == 0
assert degree(Poly(x**2+y**3,y)) == 3
assert degree(Poly(y**2 + x**3, y, x), 1) == 3
assert degree(Poly(y**2 + x**3, x), z) == 0
assert degree(Poly(y**2 + x**3 + z**4, x), z) == 4
def test_Poly_degree_list():
assert Poly(0, x).degree_list() == (-oo,)
assert Poly(0, x, y).degree_list() == (-oo, -oo)
assert Poly(0, x, y, z).degree_list() == (-oo, -oo, -oo)
assert Poly(1, x).degree_list() == (0,)
assert Poly(1, x, y).degree_list() == (0, 0)
assert Poly(1, x, y, z).degree_list() == (0, 0, 0)
assert Poly(x**2*y + x**3*z**2 + 1).degree_list() == (3, 1, 2)
assert degree_list(1, x) == (0,)
assert degree_list(x, x) == (1,)
assert degree_list(x*y**2) == (1, 2)
raises(ComputationFailed, lambda: degree_list(1))
def test_Poly_total_degree():
assert Poly(x**2*y + x**3*z**2 + 1).total_degree() == 5
assert Poly(x**2 + z**3).total_degree() == 3
assert Poly(x*y*z + z**4).total_degree() == 4
assert Poly(x**3 + x + 1).total_degree() == 3
assert total_degree(x*y + z**3) == 3
assert total_degree(x*y + z**3, x, y) == 2
assert total_degree(1) == 0
assert total_degree(Poly(y**2 + x**3 + z**4)) == 4
assert total_degree(Poly(y**2 + x**3 + z**4, x)) == 3
assert total_degree(Poly(y**2 + x**3 + z**4, x), z) == 4
assert total_degree(Poly(x**9 + x*z*y + x**3*z**2 + z**7,x), z) == 7
def test_Poly_homogenize():
assert Poly(x**2+y).homogenize(z) == Poly(x**2+y*z)
assert Poly(x+y).homogenize(z) == Poly(x+y, x, y, z)
assert Poly(x+y**2).homogenize(y) == Poly(x*y+y**2)
def test_Poly_homogeneous_order():
assert Poly(0, x, y).homogeneous_order() == -oo
assert Poly(1, x, y).homogeneous_order() == 0
assert Poly(x, x, y).homogeneous_order() == 1
assert Poly(x*y, x, y).homogeneous_order() == 2
assert Poly(x + 1, x, y).homogeneous_order() is None
assert Poly(x*y + x, x, y).homogeneous_order() is None
assert Poly(x**5 + 2*x**3*y**2 + 9*x*y**4).homogeneous_order() == 5
assert Poly(x**5 + 2*x**3*y**3 + 9*x*y**4).homogeneous_order() is None
def test_Poly_LC():
assert Poly(0, x).LC() == 0
assert Poly(1, x).LC() == 1
assert Poly(2*x**2 + x, x).LC() == 2
assert Poly(x*y**7 + 2*x**2*y**3).LC('lex') == 2
assert Poly(x*y**7 + 2*x**2*y**3).LC('grlex') == 1
assert LC(x*y**7 + 2*x**2*y**3, order='lex') == 2
assert LC(x*y**7 + 2*x**2*y**3, order='grlex') == 1
def test_Poly_TC():
assert Poly(0, x).TC() == 0
assert Poly(1, x).TC() == 1
assert Poly(2*x**2 + x, x).TC() == 0
def test_Poly_EC():
assert Poly(0, x).EC() == 0
assert Poly(1, x).EC() == 1
assert Poly(2*x**2 + x, x).EC() == 1
assert Poly(x*y**7 + 2*x**2*y**3).EC('lex') == 1
assert Poly(x*y**7 + 2*x**2*y**3).EC('grlex') == 2
def test_Poly_coeff():
assert Poly(0, x).coeff_monomial(1) == 0
assert Poly(0, x).coeff_monomial(x) == 0
assert Poly(1, x).coeff_monomial(1) == 1
assert Poly(1, x).coeff_monomial(x) == 0
assert Poly(x**8, x).coeff_monomial(1) == 0
assert Poly(x**8, x).coeff_monomial(x**7) == 0
assert Poly(x**8, x).coeff_monomial(x**8) == 1
assert Poly(x**8, x).coeff_monomial(x**9) == 0
assert Poly(3*x*y**2 + 1, x, y).coeff_monomial(1) == 1
assert Poly(3*x*y**2 + 1, x, y).coeff_monomial(x*y**2) == 3
p = Poly(24*x*y*exp(8) + 23*x, x, y)
assert p.coeff_monomial(x) == 23
assert p.coeff_monomial(y) == 0
assert p.coeff_monomial(x*y) == 24*exp(8)
assert p.as_expr().coeff(x) == 24*y*exp(8) + 23
raises(NotImplementedError, lambda: p.coeff(x))
raises(ValueError, lambda: Poly(x + 1).coeff_monomial(0))
raises(ValueError, lambda: Poly(x + 1).coeff_monomial(3*x))
raises(ValueError, lambda: Poly(x + 1).coeff_monomial(3*x*y))
def test_Poly_nth():
assert Poly(0, x).nth(0) == 0
assert Poly(0, x).nth(1) == 0
assert Poly(1, x).nth(0) == 1
assert Poly(1, x).nth(1) == 0
assert Poly(x**8, x).nth(0) == 0
assert Poly(x**8, x).nth(7) == 0
assert Poly(x**8, x).nth(8) == 1
assert Poly(x**8, x).nth(9) == 0
assert Poly(3*x*y**2 + 1, x, y).nth(0, 0) == 1
assert Poly(3*x*y**2 + 1, x, y).nth(1, 2) == 3
raises(ValueError, lambda: Poly(x*y + 1, x, y).nth(1))
def test_Poly_LM():
assert Poly(0, x).LM() == (0,)
assert Poly(1, x).LM() == (0,)
assert Poly(2*x**2 + x, x).LM() == (2,)
assert Poly(x*y**7 + 2*x**2*y**3).LM('lex') == (2, 3)
assert Poly(x*y**7 + 2*x**2*y**3).LM('grlex') == (1, 7)
assert LM(x*y**7 + 2*x**2*y**3, order='lex') == x**2*y**3
assert LM(x*y**7 + 2*x**2*y**3, order='grlex') == x*y**7
def test_Poly_LM_custom_order():
f = Poly(x**2*y**3*z + x**2*y*z**3 + x*y*z + 1)
rev_lex = lambda monom: tuple(reversed(monom))
assert f.LM(order='lex') == (2, 3, 1)
assert f.LM(order=rev_lex) == (2, 1, 3)
def test_Poly_EM():
assert Poly(0, x).EM() == (0,)
assert Poly(1, x).EM() == (0,)
assert Poly(2*x**2 + x, x).EM() == (1,)
assert Poly(x*y**7 + 2*x**2*y**3).EM('lex') == (1, 7)
assert Poly(x*y**7 + 2*x**2*y**3).EM('grlex') == (2, 3)
def test_Poly_LT():
assert Poly(0, x).LT() == ((0,), 0)
assert Poly(1, x).LT() == ((0,), 1)
assert Poly(2*x**2 + x, x).LT() == ((2,), 2)
assert Poly(x*y**7 + 2*x**2*y**3).LT('lex') == ((2, 3), 2)
assert Poly(x*y**7 + 2*x**2*y**3).LT('grlex') == ((1, 7), 1)
assert LT(x*y**7 + 2*x**2*y**3, order='lex') == 2*x**2*y**3
assert LT(x*y**7 + 2*x**2*y**3, order='grlex') == x*y**7
def test_Poly_ET():
assert Poly(0, x).ET() == ((0,), 0)
assert Poly(1, x).ET() == ((0,), 1)
assert Poly(2*x**2 + x, x).ET() == ((1,), 1)
assert Poly(x*y**7 + 2*x**2*y**3).ET('lex') == ((1, 7), 1)
assert Poly(x*y**7 + 2*x**2*y**3).ET('grlex') == ((2, 3), 2)
def test_Poly_max_norm():
assert Poly(-1, x).max_norm() == 1
assert Poly( 0, x).max_norm() == 0
assert Poly( 1, x).max_norm() == 1
def test_Poly_l1_norm():
assert Poly(-1, x).l1_norm() == 1
assert Poly( 0, x).l1_norm() == 0
assert Poly( 1, x).l1_norm() == 1
def test_Poly_clear_denoms():
coeff, poly = Poly(x + 2, x).clear_denoms()
assert coeff == 1 and poly == Poly(
x + 2, x, domain='ZZ') and poly.get_domain() == ZZ
coeff, poly = Poly(x/2 + 1, x).clear_denoms()
assert coeff == 2 and poly == Poly(
x + 2, x, domain='QQ') and poly.get_domain() == QQ
coeff, poly = Poly(x/2 + 1, x).clear_denoms(convert=True)
assert coeff == 2 and poly == Poly(
x + 2, x, domain='ZZ') and poly.get_domain() == ZZ
coeff, poly = Poly(x/y + 1, x).clear_denoms(convert=True)
assert coeff == y and poly == Poly(
x + y, x, domain='ZZ[y]') and poly.get_domain() == ZZ[y]
coeff, poly = Poly(x/3 + sqrt(2), x, domain='EX').clear_denoms()
assert coeff == 3 and poly == Poly(
x + 3*sqrt(2), x, domain='EX') and poly.get_domain() == EX
coeff, poly = Poly(
x/3 + sqrt(2), x, domain='EX').clear_denoms(convert=True)
assert coeff == 3 and poly == Poly(
x + 3*sqrt(2), x, domain='EX') and poly.get_domain() == EX
def test_Poly_rat_clear_denoms():
f = Poly(x**2/y + 1, x)
g = Poly(x**3 + y, x)
assert f.rat_clear_denoms(g) == \
(Poly(x**2 + y, x), Poly(y*x**3 + y**2, x))
f = f.set_domain(EX)
g = g.set_domain(EX)
assert f.rat_clear_denoms(g) == (f, g)
def test_Poly_integrate():
assert Poly(x + 1).integrate() == Poly(x**2/2 + x)
assert Poly(x + 1).integrate(x) == Poly(x**2/2 + x)
assert Poly(x + 1).integrate((x, 1)) == Poly(x**2/2 + x)
assert Poly(x*y + 1).integrate(x) == Poly(x**2*y/2 + x)
assert Poly(x*y + 1).integrate(y) == Poly(x*y**2/2 + y)
assert Poly(x*y + 1).integrate(x, x) == Poly(x**3*y/6 + x**2/2)
assert Poly(x*y + 1).integrate(y, y) == Poly(x*y**3/6 + y**2/2)
assert Poly(x*y + 1).integrate((x, 2)) == Poly(x**3*y/6 + x**2/2)
assert Poly(x*y + 1).integrate((y, 2)) == Poly(x*y**3/6 + y**2/2)
assert Poly(x*y + 1).integrate(x, y) == Poly(x**2*y**2/4 + x*y)
assert Poly(x*y + 1).integrate(y, x) == Poly(x**2*y**2/4 + x*y)
def test_Poly_diff():
assert Poly(x**2 + x).diff() == Poly(2*x + 1)
assert Poly(x**2 + x).diff(x) == Poly(2*x + 1)
assert Poly(x**2 + x).diff((x, 1)) == Poly(2*x + 1)
assert Poly(x**2*y**2 + x*y).diff(x) == Poly(2*x*y**2 + y)
assert Poly(x**2*y**2 + x*y).diff(y) == Poly(2*x**2*y + x)
assert Poly(x**2*y**2 + x*y).diff(x, x) == Poly(2*y**2, x, y)
assert Poly(x**2*y**2 + x*y).diff(y, y) == Poly(2*x**2, x, y)
assert Poly(x**2*y**2 + x*y).diff((x, 2)) == Poly(2*y**2, x, y)
assert Poly(x**2*y**2 + x*y).diff((y, 2)) == Poly(2*x**2, x, y)
assert Poly(x**2*y**2 + x*y).diff(x, y) == Poly(4*x*y + 1)
assert Poly(x**2*y**2 + x*y).diff(y, x) == Poly(4*x*y + 1)
def test_issue_9585():
assert diff(Poly(x**2 + x)) == Poly(2*x + 1)
assert diff(Poly(x**2 + x), x, evaluate=False) == \
Derivative(Poly(x**2 + x), x)
assert Derivative(Poly(x**2 + x), x).doit() == Poly(2*x + 1)
def test_Poly_eval():
assert Poly(0, x).eval(7) == 0
assert Poly(1, x).eval(7) == 1
assert Poly(x, x).eval(7) == 7
assert Poly(0, x).eval(0, 7) == 0
assert Poly(1, x).eval(0, 7) == 1
assert Poly(x, x).eval(0, 7) == 7
assert Poly(0, x).eval(x, 7) == 0
assert Poly(1, x).eval(x, 7) == 1
assert Poly(x, x).eval(x, 7) == 7
assert Poly(0, x).eval('x', 7) == 0
assert Poly(1, x).eval('x', 7) == 1
assert Poly(x, x).eval('x', 7) == 7
raises(PolynomialError, lambda: Poly(1, x).eval(1, 7))
raises(PolynomialError, lambda: Poly(1, x).eval(y, 7))
raises(PolynomialError, lambda: Poly(1, x).eval('y', 7))
assert Poly(123, x, y).eval(7) == Poly(123, y)
assert Poly(2*y, x, y).eval(7) == Poly(2*y, y)
assert Poly(x*y, x, y).eval(7) == Poly(7*y, y)
assert Poly(123, x, y).eval(x, 7) == Poly(123, y)
assert Poly(2*y, x, y).eval(x, 7) == Poly(2*y, y)
assert Poly(x*y, x, y).eval(x, 7) == Poly(7*y, y)
assert Poly(123, x, y).eval(y, 7) == Poly(123, x)
assert Poly(2*y, x, y).eval(y, 7) == Poly(14, x)
assert Poly(x*y, x, y).eval(y, 7) == Poly(7*x, x)
assert Poly(x*y + y, x, y).eval({x: 7}) == Poly(8*y, y)
assert Poly(x*y + y, x, y).eval({y: 7}) == Poly(7*x + 7, x)
assert Poly(x*y + y, x, y).eval({x: 6, y: 7}) == 49
assert Poly(x*y + y, x, y).eval({x: 7, y: 6}) == 48
assert Poly(x*y + y, x, y).eval((6, 7)) == 49
assert Poly(x*y + y, x, y).eval([6, 7]) == 49
assert Poly(x + 1, domain='ZZ').eval(S(1)/2) == S(3)/2
assert Poly(x + 1, domain='ZZ').eval(sqrt(2)) == sqrt(2) + 1
raises(ValueError, lambda: Poly(x*y + y, x, y).eval((6, 7, 8)))
raises(DomainError, lambda: Poly(x + 1, domain='ZZ').eval(S(1)/2, auto=False))
# issue 6344
alpha = Symbol('alpha')
result = (2*alpha*z - 2*alpha + z**2 + 3)/(z**2 - 2*z + 1)
f = Poly(x**2 + (alpha - 1)*x - alpha + 1, x, domain='ZZ[alpha]')
assert f.eval((z + 1)/(z - 1)) == result
g = Poly(x**2 + (alpha - 1)*x - alpha + 1, x, y, domain='ZZ[alpha]')
assert g.eval((z + 1)/(z - 1)) == Poly(result, y, domain='ZZ(alpha,z)')
def test_Poly___call__():
f = Poly(2*x*y + 3*x + y + 2*z)
assert f(2) == Poly(5*y + 2*z + 6)
assert f(2, 5) == Poly(2*z + 31)
assert f(2, 5, 7) == 45
def test_parallel_poly_from_expr():
assert parallel_poly_from_expr(
[x - 1, x**2 - 1], x)[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[Poly(x - 1, x), x**2 - 1], x)[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[x - 1, Poly(x**2 - 1, x)], x)[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr([Poly(
x - 1, x), Poly(x**2 - 1, x)], x)[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[x - 1, x**2 - 1], x, y)[0] == [Poly(x - 1, x, y), Poly(x**2 - 1, x, y)]
assert parallel_poly_from_expr([Poly(
x - 1, x), x**2 - 1], x, y)[0] == [Poly(x - 1, x, y), Poly(x**2 - 1, x, y)]
assert parallel_poly_from_expr([x - 1, Poly(
x**2 - 1, x)], x, y)[0] == [Poly(x - 1, x, y), Poly(x**2 - 1, x, y)]
assert parallel_poly_from_expr([Poly(x - 1, x), Poly(
x**2 - 1, x)], x, y)[0] == [Poly(x - 1, x, y), Poly(x**2 - 1, x, y)]
assert parallel_poly_from_expr(
[x - 1, x**2 - 1])[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[Poly(x - 1, x), x**2 - 1])[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[x - 1, Poly(x**2 - 1, x)])[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[Poly(x - 1, x), Poly(x**2 - 1, x)])[0] == [Poly(x - 1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[1, x**2 - 1])[0] == [Poly(1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[1, x**2 - 1])[0] == [Poly(1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[1, Poly(x**2 - 1, x)])[0] == [Poly(1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[1, Poly(x**2 - 1, x)])[0] == [Poly(1, x), Poly(x**2 - 1, x)]
assert parallel_poly_from_expr(
[x**2 - 1, 1])[0] == [Poly(x**2 - 1, x), Poly(1, x)]
assert parallel_poly_from_expr(
[x**2 - 1, 1])[0] == [Poly(x**2 - 1, x), Poly(1, x)]
assert parallel_poly_from_expr(
[Poly(x**2 - 1, x), 1])[0] == [Poly(x**2 - 1, x), Poly(1, x)]
assert parallel_poly_from_expr(
[Poly(x**2 - 1, x), 1])[0] == [Poly(x**2 - 1, x), Poly(1, x)]
assert parallel_poly_from_expr([Poly(x, x, y), Poly(y, x, y)], x, y, order='lex')[0] == \
[Poly(x, x, y, domain='ZZ'), Poly(y, x, y, domain='ZZ')]
raises(PolificationFailed, lambda: parallel_poly_from_expr([0, 1]))
def test_pdiv():
f, g = x**2 - y**2, x - y
q, r = x + y, 0
F, G, Q, R = [ Poly(h, x, y) for h in (f, g, q, r) ]
assert F.pdiv(G) == (Q, R)
assert F.prem(G) == R
assert F.pquo(G) == Q
assert F.pexquo(G) == Q
assert pdiv(f, g) == (q, r)
assert prem(f, g) == r
assert pquo(f, g) == q
assert pexquo(f, g) == q
assert pdiv(f, g, x, y) == (q, r)
assert prem(f, g, x, y) == r
assert pquo(f, g, x, y) == q
assert pexquo(f, g, x, y) == q
assert pdiv(f, g, (x, y)) == (q, r)
assert prem(f, g, (x, y)) == r
assert pquo(f, g, (x, y)) == q
assert pexquo(f, g, (x, y)) == q
assert pdiv(F, G) == (Q, R)
assert prem(F, G) == R
assert pquo(F, G) == Q
assert pexquo(F, G) == Q
assert pdiv(f, g, polys=True) == (Q, R)
assert prem(f, g, polys=True) == R
assert pquo(f, g, polys=True) == Q
assert pexquo(f, g, polys=True) == Q
assert pdiv(F, G, polys=False) == (q, r)
assert prem(F, G, polys=False) == r
assert pquo(F, G, polys=False) == q
assert pexquo(F, G, polys=False) == q
raises(ComputationFailed, lambda: pdiv(4, 2))
raises(ComputationFailed, lambda: prem(4, 2))
raises(ComputationFailed, lambda: pquo(4, 2))
raises(ComputationFailed, lambda: pexquo(4, 2))
def test_div():
f, g = x**2 - y**2, x - y
q, r = x + y, 0
F, G, Q, R = [ Poly(h, x, y) for h in (f, g, q, r) ]
assert F.div(G) == (Q, R)
assert F.rem(G) == R
assert F.quo(G) == Q
assert F.exquo(G) == Q
assert div(f, g) == (q, r)
assert rem(f, g) == r
assert quo(f, g) == q
assert exquo(f, g) == q
assert div(f, g, x, y) == (q, r)
assert rem(f, g, x, y) == r
assert quo(f, g, x, y) == q
assert exquo(f, g, x, y) == q
assert div(f, g, (x, y)) == (q, r)
assert rem(f, g, (x, y)) == r
assert quo(f, g, (x, y)) == q
assert exquo(f, g, (x, y)) == q
assert div(F, G) == (Q, R)
assert rem(F, G) == R
assert quo(F, G) == Q
assert exquo(F, G) == Q
assert div(f, g, polys=True) == (Q, R)
assert rem(f, g, polys=True) == R
assert quo(f, g, polys=True) == Q
assert exquo(f, g, polys=True) == Q
assert div(F, G, polys=False) == (q, r)
assert rem(F, G, polys=False) == r
assert quo(F, G, polys=False) == q
assert exquo(F, G, polys=False) == q
raises(ComputationFailed, lambda: div(4, 2))
raises(ComputationFailed, lambda: rem(4, 2))
raises(ComputationFailed, lambda: quo(4, 2))
raises(ComputationFailed, lambda: exquo(4, 2))
f, g = x**2 + 1, 2*x - 4
qz, rz = 0, x**2 + 1
qq, rq = x/2 + 1, 5
assert div(f, g) == (qq, rq)
assert div(f, g, auto=True) == (qq, rq)
assert div(f, g, auto=False) == (qz, rz)
assert div(f, g, domain=ZZ) == (qz, rz)
assert div(f, g, domain=QQ) == (qq, rq)
assert div(f, g, domain=ZZ, auto=True) == (qq, rq)
assert div(f, g, domain=ZZ, auto=False) == (qz, rz)
assert div(f, g, domain=QQ, auto=True) == (qq, rq)
assert div(f, g, domain=QQ, auto=False) == (qq, rq)
assert rem(f, g) == rq
assert rem(f, g, auto=True) == rq
assert rem(f, g, auto=False) == rz
assert rem(f, g, domain=ZZ) == rz
assert rem(f, g, domain=QQ) == rq
assert rem(f, g, domain=ZZ, auto=True) == rq
assert rem(f, g, domain=ZZ, auto=False) == rz
assert rem(f, g, domain=QQ, auto=True) == rq
assert rem(f, g, domain=QQ, auto=False) == rq
assert quo(f, g) == qq
assert quo(f, g, auto=True) == qq
assert quo(f, g, auto=False) == qz
assert quo(f, g, domain=ZZ) == qz
assert quo(f, g, domain=QQ) == qq
assert quo(f, g, domain=ZZ, auto=True) == qq
assert quo(f, g, domain=ZZ, auto=False) == qz
assert quo(f, g, domain=QQ, auto=True) == qq
assert quo(f, g, domain=QQ, auto=False) == qq
f, g, q = x**2, 2*x, x/2
assert exquo(f, g) == q
assert exquo(f, g, auto=True) == q
raises(ExactQuotientFailed, lambda: exquo(f, g, auto=False))
raises(ExactQuotientFailed, lambda: exquo(f, g, domain=ZZ))
assert exquo(f, g, domain=QQ) == q
assert exquo(f, g, domain=ZZ, auto=True) == q
raises(ExactQuotientFailed, lambda: exquo(f, g, domain=ZZ, auto=False))
assert exquo(f, g, domain=QQ, auto=True) == q
assert exquo(f, g, domain=QQ, auto=False) == q
f, g = Poly(x**2), Poly(x)
q, r = f.div(g)
assert q.get_domain().is_ZZ and r.get_domain().is_ZZ
r = f.rem(g)
assert r.get_domain().is_ZZ
q = f.quo(g)
assert q.get_domain().is_ZZ
q = f.exquo(g)
assert q.get_domain().is_ZZ
f, g = Poly(x+y, x), Poly(2*x+y, x)
q, r = f.div(g)
assert q.get_domain().is_Frac and r.get_domain().is_Frac
def test_gcdex():
f, g = 2*x, x**2 - 16
s, t, h = x/32, -Rational(1, 16), 1
F, G, S, T, H = [ Poly(u, x, domain='QQ') for u in (f, g, s, t, h) ]
assert F.half_gcdex(G) == (S, H)
assert F.gcdex(G) == (S, T, H)
assert F.invert(G) == S
assert half_gcdex(f, g) == (s, h)
assert gcdex(f, g) == (s, t, h)
assert invert(f, g) == s
assert half_gcdex(f, g, x) == (s, h)
assert gcdex(f, g, x) == (s, t, h)
assert invert(f, g, x) == s
assert half_gcdex(f, g, (x,)) == (s, h)
assert gcdex(f, g, (x,)) == (s, t, h)
assert invert(f, g, (x,)) == s
assert half_gcdex(F, G) == (S, H)
assert gcdex(F, G) == (S, T, H)
assert invert(F, G) == S
assert half_gcdex(f, g, polys=True) == (S, H)
assert gcdex(f, g, polys=True) == (S, T, H)
assert invert(f, g, polys=True) == S
assert half_gcdex(F, G, polys=False) == (s, h)
assert gcdex(F, G, polys=False) == (s, t, h)
assert invert(F, G, polys=False) == s
assert half_gcdex(100, 2004) == (-20, 4)
assert gcdex(100, 2004) == (-20, 1, 4)
assert invert(3, 7) == 5
raises(DomainError, lambda: half_gcdex(x + 1, 2*x + 1, auto=False))
raises(DomainError, lambda: gcdex(x + 1, 2*x + 1, auto=False))
raises(DomainError, lambda: invert(x + 1, 2*x + 1, auto=False))
def test_revert():
f = Poly(1 - x**2/2 + x**4/24 - x**6/720)
g = Poly(61*x**6/720 + 5*x**4/24 + x**2/2 + 1)
assert f.revert(8) == g
def test_subresultants():
f, g, h = x**2 - 2*x + 1, x**2 - 1, 2*x - 2
F, G, H = Poly(f), Poly(g), Poly(h)
assert F.subresultants(G) == [F, G, H]
assert subresultants(f, g) == [f, g, h]
assert subresultants(f, g, x) == [f, g, h]
assert subresultants(f, g, (x,)) == [f, g, h]
assert subresultants(F, G) == [F, G, H]
assert subresultants(f, g, polys=True) == [F, G, H]
assert subresultants(F, G, polys=False) == [f, g, h]
raises(ComputationFailed, lambda: subresultants(4, 2))
def test_resultant():
f, g, h = x**2 - 2*x + 1, x**2 - 1, 0
F, G = Poly(f), Poly(g)
assert F.resultant(G) == h
assert resultant(f, g) == h
assert resultant(f, g, x) == h
assert resultant(f, g, (x,)) == h
assert resultant(F, G) == h
assert resultant(f, g, polys=True) == h
assert resultant(F, G, polys=False) == h
assert resultant(f, g, includePRS=True) == (h, [f, g, 2*x - 2])
f, g, h = x - a, x - b, a - b
F, G, H = Poly(f), Poly(g), Poly(h)
assert F.resultant(G) == H
assert resultant(f, g) == h
assert resultant(f, g, x) == h
assert resultant(f, g, (x,)) == h
assert resultant(F, G) == H
assert resultant(f, g, polys=True) == H
assert resultant(F, G, polys=False) == h
raises(ComputationFailed, lambda: resultant(4, 2))
def test_discriminant():
f, g = x**3 + 3*x**2 + 9*x - 13, -11664
F = Poly(f)
assert F.discriminant() == g
assert discriminant(f) == g
assert discriminant(f, x) == g
assert discriminant(f, (x,)) == g
assert discriminant(F) == g
assert discriminant(f, polys=True) == g
assert discriminant(F, polys=False) == g
f, g = a*x**2 + b*x + c, b**2 - 4*a*c
F, G = Poly(f), Poly(g)
assert F.discriminant() == G
assert discriminant(f) == g
assert discriminant(f, x, a, b, c) == g
assert discriminant(f, (x, a, b, c)) == g
assert discriminant(F) == G
assert discriminant(f, polys=True) == G
assert discriminant(F, polys=False) == g
raises(ComputationFailed, lambda: discriminant(4))
def test_dispersion():
# We test only the API here. For more mathematical
# tests see the dedicated test file.
fp = poly((x + 1)*(x + 2), x)
assert sorted(fp.dispersionset()) == [0, 1]
assert fp.dispersion() == 1
fp = poly(x**4 - 3*x**2 + 1, x)
gp = fp.shift(-3)
assert sorted(fp.dispersionset(gp)) == [2, 3, 4]
assert fp.dispersion(gp) == 4
def test_gcd_list():
F = [x**3 - 1, x**2 - 1, x**2 - 3*x + 2]
assert gcd_list(F) == x - 1
assert gcd_list(F, polys=True) == Poly(x - 1)
assert gcd_list([]) == 0
assert gcd_list([1, 2]) == 1
assert gcd_list([4, 6, 8]) == 2
assert gcd_list([x*(y + 42) - x*y - x*42]) == 0
gcd = gcd_list([], x)
assert gcd.is_Number and gcd is S.Zero
gcd = gcd_list([], x, polys=True)
assert gcd.is_Poly and gcd.is_zero
raises(ComputationFailed, lambda: gcd_list([], polys=True))
def test_lcm_list():
F = [x**3 - 1, x**2 - 1, x**2 - 3*x + 2]
assert lcm_list(F) == x**5 - x**4 - 2*x**3 - x**2 + x + 2
assert lcm_list(F, polys=True) == Poly(x**5 - x**4 - 2*x**3 - x**2 + x + 2)
assert lcm_list([]) == 1
assert lcm_list([1, 2]) == 2
assert lcm_list([4, 6, 8]) == 24
assert lcm_list([x*(y + 42) - x*y - x*42]) == 0
lcm = lcm_list([], x)
assert lcm.is_Number and lcm is S.One
lcm = lcm_list([], x, polys=True)
assert lcm.is_Poly and lcm.is_one
raises(ComputationFailed, lambda: lcm_list([], polys=True))
def test_gcd():
f, g = x**3 - 1, x**2 - 1
s, t = x**2 + x + 1, x + 1
h, r = x - 1, x**4 + x**3 - x - 1
F, G, S, T, H, R = [ Poly(u) for u in (f, g, s, t, h, r) ]
assert F.cofactors(G) == (H, S, T)
assert F.gcd(G) == H
assert F.lcm(G) == R
assert cofactors(f, g) == (h, s, t)
assert gcd(f, g) == h
assert lcm(f, g) == r
assert cofactors(f, g, x) == (h, s, t)
assert gcd(f, g, x) == h
assert lcm(f, g, x) == r
assert cofactors(f, g, (x,)) == (h, s, t)
assert gcd(f, g, (x,)) == h
assert lcm(f, g, (x,)) == r
assert cofactors(F, G) == (H, S, T)
assert gcd(F, G) == H
assert lcm(F, G) == R
assert cofactors(f, g, polys=True) == (H, S, T)
assert gcd(f, g, polys=True) == H
assert lcm(f, g, polys=True) == R
assert cofactors(F, G, polys=False) == (h, s, t)
assert gcd(F, G, polys=False) == h
assert lcm(F, G, polys=False) == r
f, g = 1.0*x**2 - 1.0, 1.0*x - 1.0
h, s, t = g, 1.0*x + 1.0, 1.0
assert cofactors(f, g) == (h, s, t)
assert gcd(f, g) == h
assert lcm(f, g) == f
f, g = 1.0*x**2 - 1.0, 1.0*x - 1.0
h, s, t = g, 1.0*x + 1.0, 1.0
assert cofactors(f, g) == (h, s, t)
assert gcd(f, g) == h
assert lcm(f, g) == f
assert cofactors(8, 6) == (2, 4, 3)
assert gcd(8, 6) == 2
assert lcm(8, 6) == 24
f, g = x**2 - 3*x - 4, x**3 - 4*x**2 + x - 4
l = x**4 - 3*x**3 - 3*x**2 - 3*x - 4
h, s, t = x - 4, x + 1, x**2 + 1
assert cofactors(f, g, modulus=11) == (h, s, t)
assert gcd(f, g, modulus=11) == h
assert lcm(f, g, modulus=11) == l
f, g = x**2 + 8*x + 7, x**3 + 7*x**2 + x + 7
l = x**4 + 8*x**3 + 8*x**2 + 8*x + 7
h, s, t = x + 7, x + 1, x**2 + 1
assert cofactors(f, g, modulus=11, symmetric=False) == (h, s, t)
assert gcd(f, g, modulus=11, symmetric=False) == h
assert lcm(f, g, modulus=11, symmetric=False) == l
raises(TypeError, lambda: gcd(x))
raises(TypeError, lambda: lcm(x))
def test_gcd_numbers_vs_polys():
assert isinstance(gcd(3, 9), Integer)
assert isinstance(gcd(3*x, 9), Integer)
assert gcd(3, 9) == 3
assert gcd(3*x, 9) == 3
assert isinstance(gcd(S(3)/2, S(9)/4), Rational)
assert isinstance(gcd(S(3)/2*x, S(9)/4), Rational)
assert gcd(S(3)/2, S(9)/4) == S(3)/4
assert gcd(S(3)/2*x, S(9)/4) == 1
assert isinstance(gcd(3.0, 9.0), Float)
assert isinstance(gcd(3.0*x, 9.0), Float)
assert gcd(3.0, 9.0) == 1.0
assert gcd(3.0*x, 9.0) == 1.0
def test_terms_gcd():
assert terms_gcd(1) == 1
assert terms_gcd(1, x) == 1
assert terms_gcd(x - 1) == x - 1
assert terms_gcd(-x - 1) == -x - 1
assert terms_gcd(2*x + 3) == 2*x + 3
assert terms_gcd(6*x + 4) == Mul(2, 3*x + 2, evaluate=False)
assert terms_gcd(x**3*y + x*y**3) == x*y*(x**2 + y**2)
assert terms_gcd(2*x**3*y + 2*x*y**3) == 2*x*y*(x**2 + y**2)
assert terms_gcd(x**3*y/2 + x*y**3/2) == x*y/2*(x**2 + y**2)
assert terms_gcd(x**3*y + 2*x*y**3) == x*y*(x**2 + 2*y**2)
assert terms_gcd(2*x**3*y + 4*x*y**3) == 2*x*y*(x**2 + 2*y**2)
assert terms_gcd(2*x**3*y/3 + 4*x*y**3/5) == 2*x*y/15*(5*x**2 + 6*y**2)
assert terms_gcd(2.0*x**3*y + 4.1*x*y**3) == x*y*(2.0*x**2 + 4.1*y**2)
assert _aresame(terms_gcd(2.0*x + 3), 2.0*x + 3)
assert terms_gcd((3 + 3*x)*(x + x*y), expand=False) == \
(3*x + 3)*(x*y + x)
assert terms_gcd((3 + 3*x)*(x + x*sin(3 + 3*y)), expand=False, deep=True) == \
3*x*(x + 1)*(sin(Mul(3, y + 1, evaluate=False)) + 1)
assert terms_gcd(sin(x + x*y), deep=True) == \
sin(x*(y + 1))
eq = Eq(2*x, 2*y + 2*z*y)
assert terms_gcd(eq) == eq
assert terms_gcd(eq, deep=True) == Eq(2*x, 2*y*(z + 1))
def test_trunc():
f, g = x**5 + 2*x**4 + 3*x**3 + 4*x**2 + 5*x + 6, x**5 - x**4 + x**2 - x
F, G = Poly(f), Poly(g)
assert F.trunc(3) == G
assert trunc(f, 3) == g
assert trunc(f, 3, x) == g
assert trunc(f, 3, (x,)) == g
assert trunc(F, 3) == G
assert trunc(f, 3, polys=True) == G
assert trunc(F, 3, polys=False) == g
f, g = 6*x**5 + 5*x**4 + 4*x**3 + 3*x**2 + 2*x + 1, -x**4 + x**3 - x + 1
F, G = Poly(f), Poly(g)
assert F.trunc(3) == G
assert trunc(f, 3) == g
assert trunc(f, 3, x) == g
assert trunc(f, 3, (x,)) == g
assert trunc(F, 3) == G
assert trunc(f, 3, polys=True) == G
assert trunc(F, 3, polys=False) == g
f = Poly(x**2 + 2*x + 3, modulus=5)
assert f.trunc(2) == Poly(x**2 + 1, modulus=5)
def test_monic():
f, g = 2*x - 1, x - S(1)/2
F, G = Poly(f, domain='QQ'), Poly(g)
assert F.monic() == G
assert monic(f) == g
assert monic(f, x) == g
assert monic(f, (x,)) == g
assert monic(F) == G
assert monic(f, polys=True) == G
assert monic(F, polys=False) == g
raises(ComputationFailed, lambda: monic(4))
assert monic(2*x**2 + 6*x + 4, auto=False) == x**2 + 3*x + 2
raises(ExactQuotientFailed, lambda: monic(2*x + 6*x + 1, auto=False))
assert monic(2.0*x**2 + 6.0*x + 4.0) == 1.0*x**2 + 3.0*x + 2.0
assert monic(2*x**2 + 3*x + 4, modulus=5) == x**2 - x + 2
def test_content():
f, F = 4*x + 2, Poly(4*x + 2)
assert F.content() == 2
assert content(f) == 2
raises(ComputationFailed, lambda: content(4))
f = Poly(2*x, modulus=3)
assert f.content() == 1
def test_primitive():
f, g = 4*x + 2, 2*x + 1
F, G = Poly(f), Poly(g)
assert F.primitive() == (2, G)
assert primitive(f) == (2, g)
assert primitive(f, x) == (2, g)
assert primitive(f, (x,)) == (2, g)
assert primitive(F) == (2, G)
assert primitive(f, polys=True) == (2, G)
assert primitive(F, polys=False) == (2, g)
raises(ComputationFailed, lambda: primitive(4))
f = Poly(2*x, modulus=3)
g = Poly(2.0*x, domain=RR)
assert f.primitive() == (1, f)
assert g.primitive() == (1.0, g)
assert primitive(S('-3*x/4 + y + 11/8')) == \
S('(1/8, -6*x + 8*y + 11)')
def test_compose():
f = x**12 + 20*x**10 + 150*x**8 + 500*x**6 + 625*x**4 - 2*x**3 - 10*x + 9
g = x**4 - 2*x + 9
h = x**3 + 5*x
F, G, H = map(Poly, (f, g, h))
assert G.compose(H) == F
assert compose(g, h) == f
assert compose(g, h, x) == f
assert compose(g, h, (x,)) == f
assert compose(G, H) == F
assert compose(g, h, polys=True) == F
assert compose(G, H, polys=False) == f
assert F.decompose() == [G, H]
assert decompose(f) == [g, h]
assert decompose(f, x) == [g, h]
assert decompose(f, (x,)) == [g, h]
assert decompose(F) == [G, H]
assert decompose(f, polys=True) == [G, H]
assert decompose(F, polys=False) == [g, h]
raises(ComputationFailed, lambda: compose(4, 2))
raises(ComputationFailed, lambda: decompose(4))
assert compose(x**2 - y**2, x - y, x, y) == x**2 - 2*x*y
assert compose(x**2 - y**2, x - y, y, x) == -y**2 + 2*x*y
def test_shift():
assert Poly(x**2 - 2*x + 1, x).shift(2) == Poly(x**2 + 2*x + 1, x)
def test_transform():
# Also test that 3-way unification is done correctly
assert Poly(x**2 - 2*x + 1, x).transform(Poly(x + 1), Poly(x - 1)) == \
Poly(4, x) == \
cancel((x - 1)**2*(x**2 - 2*x + 1).subs(x, (x + 1)/(x - 1)))
assert Poly(x**2 - x/2 + 1, x).transform(Poly(x + 1), Poly(x - 1)) == \
Poly(3*x**2/2 + S(5)/2, x) == \
cancel((x - 1)**2*(x**2 - x/2 + 1).subs(x, (x + 1)/(x - 1)))
assert Poly(x**2 - 2*x + 1, x).transform(Poly(x + S(1)/2), Poly(x - 1)) == \
Poly(S(9)/4, x) == \
cancel((x - 1)**2*(x**2 - 2*x + 1).subs(x, (x + S(1)/2)/(x - 1)))
assert Poly(x**2 - 2*x + 1, x).transform(Poly(x + 1), Poly(x - S(1)/2)) == \
Poly(S(9)/4, x) == \
cancel((x - S(1)/2)**2*(x**2 - 2*x + 1).subs(x, (x + 1)/(x - S(1)/2)))
# Unify ZZ, QQ, and RR
assert Poly(x**2 - 2*x + 1, x).transform(Poly(x + 1.0), Poly(x - S(1)/2)) == \
Poly(S(9)/4, x) == \
cancel((x - S(1)/2)**2*(x**2 - 2*x + 1).subs(x, (x + 1.0)/(x - S(1)/2)))
raises(ValueError, lambda: Poly(x*y).transform(Poly(x + 1), Poly(x - 1)))
raises(ValueError, lambda: Poly(x).transform(Poly(y + 1), Poly(x - 1)))
raises(ValueError, lambda: Poly(x).transform(Poly(x + 1), Poly(y - 1)))
raises(ValueError, lambda: Poly(x).transform(Poly(x*y + 1), Poly(x - 1)))
raises(ValueError, lambda: Poly(x).transform(Poly(x + 1), Poly(x*y - 1)))
def test_sturm():
f, F = x, Poly(x, domain='QQ')
g, G = 1, Poly(1, x, domain='QQ')
assert F.sturm() == [F, G]
assert sturm(f) == [f, g]
assert sturm(f, x) == [f, g]
assert sturm(f, (x,)) == [f, g]
assert sturm(F) == [F, G]
assert sturm(f, polys=True) == [F, G]
assert sturm(F, polys=False) == [f, g]
raises(ComputationFailed, lambda: sturm(4))
raises(DomainError, lambda: sturm(f, auto=False))
f = Poly(S(1024)/(15625*pi**8)*x**5
- S(4096)/(625*pi**8)*x**4
+ S(32)/(15625*pi**4)*x**3
- S(128)/(625*pi**4)*x**2
+ S(1)/62500*x
- S(1)/625, x, domain='ZZ(pi)')
assert sturm(f) == \
[Poly(x**3 - 100*x**2 + pi**4/64*x - 25*pi**4/16, x, domain='ZZ(pi)'),
Poly(3*x**2 - 200*x + pi**4/64, x, domain='ZZ(pi)'),
Poly((S(20000)/9 - pi**4/96)*x + 25*pi**4/18, x, domain='ZZ(pi)'),
Poly((-3686400000000*pi**4 - 11520000*pi**8 - 9*pi**12)/(26214400000000 - 245760000*pi**4 + 576*pi**8), x, domain='ZZ(pi)')]
def test_gff():
f = x**5 + 2*x**4 - x**3 - 2*x**2
assert Poly(f).gff_list() == [(Poly(x), 1), (Poly(x + 2), 4)]
assert gff_list(f) == [(x, 1), (x + 2, 4)]
raises(NotImplementedError, lambda: gff(f))
f = x*(x - 1)**3*(x - 2)**2*(x - 4)**2*(x - 5)
assert Poly(f).gff_list() == [(
Poly(x**2 - 5*x + 4), 1), (Poly(x**2 - 5*x + 4), 2), (Poly(x), 3)]
assert gff_list(f) == [(x**2 - 5*x + 4, 1), (x**2 - 5*x + 4, 2), (x, 3)]
raises(NotImplementedError, lambda: gff(f))
def test_norm():
a, b = sqrt(2), sqrt(3)
f = Poly(a*x + b*y, x, y, extension=(a, b))
assert f.norm() == Poly(4*x**4 - 12*x**2*y**2 + 9*y**4, x, y, domain='QQ')
def test_sqf_norm():
assert sqf_norm(x**2 - 2, extension=sqrt(3)) == \
(1, x**2 - 2*sqrt(3)*x + 1, x**4 - 10*x**2 + 1)
assert sqf_norm(x**2 - 3, extension=sqrt(2)) == \
(1, x**2 - 2*sqrt(2)*x - 1, x**4 - 10*x**2 + 1)
assert Poly(x**2 - 2, extension=sqrt(3)).sqf_norm() == \
(1, Poly(x**2 - 2*sqrt(3)*x + 1, x, extension=sqrt(3)),
Poly(x**4 - 10*x**2 + 1, x, domain='QQ'))
assert Poly(x**2 - 3, extension=sqrt(2)).sqf_norm() == \
(1, Poly(x**2 - 2*sqrt(2)*x - 1, x, extension=sqrt(2)),
Poly(x**4 - 10*x**2 + 1, x, domain='QQ'))
def test_sqf():
f = x**5 - x**3 - x**2 + 1
g = x**3 + 2*x**2 + 2*x + 1
h = x - 1
p = x**4 + x**3 - x - 1
F, G, H, P = map(Poly, (f, g, h, p))
assert F.sqf_part() == P
assert sqf_part(f) == p
assert sqf_part(f, x) == p
assert sqf_part(f, (x,)) == p
assert sqf_part(F) == P
assert sqf_part(f, polys=True) == P
assert sqf_part(F, polys=False) == p
assert F.sqf_list() == (1, [(G, 1), (H, 2)])
assert sqf_list(f) == (1, [(g, 1), (h, 2)])
assert sqf_list(f, x) == (1, [(g, 1), (h, 2)])
assert sqf_list(f, (x,)) == (1, [(g, 1), (h, 2)])
assert sqf_list(F) == (1, [(G, 1), (H, 2)])
assert sqf_list(f, polys=True) == (1, [(G, 1), (H, 2)])
assert sqf_list(F, polys=False) == (1, [(g, 1), (h, 2)])
assert F.sqf_list_include() == [(G, 1), (H, 2)]
raises(ComputationFailed, lambda: sqf_part(4))
assert sqf(1) == 1
assert sqf_list(1) == (1, [])
assert sqf((2*x**2 + 2)**7) == 128*(x**2 + 1)**7
assert sqf(f) == g*h**2
assert sqf(f, x) == g*h**2
assert sqf(f, (x,)) == g*h**2
d = x**2 + y**2
assert sqf(f/d) == (g*h**2)/d
assert sqf(f/d, x) == (g*h**2)/d
assert sqf(f/d, (x,)) == (g*h**2)/d
assert sqf(x - 1) == x - 1
assert sqf(-x - 1) == -x - 1
assert sqf(x - 1) == x - 1
assert sqf(6*x - 10) == Mul(2, 3*x - 5, evaluate=False)
assert sqf((6*x - 10)/(3*x - 6)) == S(2)/3*((3*x - 5)/(x - 2))
assert sqf(Poly(x**2 - 2*x + 1)) == (x - 1)**2
f = 3 + x - x*(1 + x) + x**2
assert sqf(f) == 3
f = (x**2 + 2*x + 1)**20000000000
assert sqf(f) == (x + 1)**40000000000
assert sqf_list(f) == (1, [(x + 1, 40000000000)])
def test_factor():
f = x**5 - x**3 - x**2 + 1
u = x + 1
v = x - 1
w = x**2 + x + 1
F, U, V, W = map(Poly, (f, u, v, w))
assert F.factor_list() == (1, [(U, 1), (V, 2), (W, 1)])
assert factor_list(f) == (1, [(u, 1), (v, 2), (w, 1)])
assert factor_list(f, x) == (1, [(u, 1), (v, 2), (w, 1)])
assert factor_list(f, (x,)) == (1, [(u, 1), (v, 2), (w, 1)])
assert factor_list(F) == (1, [(U, 1), (V, 2), (W, 1)])
assert factor_list(f, polys=True) == (1, [(U, 1), (V, 2), (W, 1)])
assert factor_list(F, polys=False) == (1, [(u, 1), (v, 2), (w, 1)])
assert F.factor_list_include() == [(U, 1), (V, 2), (W, 1)]
assert factor_list(1) == (1, [])
assert factor_list(6) == (6, [])
assert factor_list(sqrt(3), x) == (sqrt(3), [])
assert factor_list((-1)**x, x) == (1, [(-1, x)])
assert factor_list((2*x)**y, x) == (1, [(2, y), (x, y)])
assert factor_list(sqrt(x*y), x) == (1, [(x*y, S.Half)])
assert factor(6) == 6 and factor(6).is_Integer
assert factor_list(3*x) == (3, [(x, 1)])
assert factor_list(3*x**2) == (3, [(x, 2)])
assert factor(3*x) == 3*x
assert factor(3*x**2) == 3*x**2
assert factor((2*x**2 + 2)**7) == 128*(x**2 + 1)**7
assert factor(f) == u*v**2*w
assert factor(f, x) == u*v**2*w
assert factor(f, (x,)) == u*v**2*w
g, p, q, r = x**2 - y**2, x - y, x + y, x**2 + 1
assert factor(f/g) == (u*v**2*w)/(p*q)
assert factor(f/g, x) == (u*v**2*w)/(p*q)
assert factor(f/g, (x,)) == (u*v**2*w)/(p*q)
p = Symbol('p', positive=True)
i = Symbol('i', integer=True)
r = Symbol('r', real=True)
assert factor(sqrt(x*y)).is_Pow is True
assert factor(sqrt(3*x**2 - 3)) == sqrt(3)*sqrt((x - 1)*(x + 1))
assert factor(sqrt(3*x**2 + 3)) == sqrt(3)*sqrt(x**2 + 1)
assert factor((y*x**2 - y)**i) == y**i*(x - 1)**i*(x + 1)**i
assert factor((y*x**2 + y)**i) == y**i*(x**2 + 1)**i
assert factor((y*x**2 - y)**t) == (y*(x - 1)*(x + 1))**t
assert factor((y*x**2 + y)**t) == (y*(x**2 + 1))**t
f = sqrt(expand((r**2 + 1)*(p + 1)*(p - 1)*(p - 2)**3))
g = sqrt((p - 2)**3*(p - 1))*sqrt(p + 1)*sqrt(r**2 + 1)
assert factor(f) == g
assert factor(g) == g
g = (x - 1)**5*(r**2 + 1)
f = sqrt(expand(g))
assert factor(f) == sqrt(g)
f = Poly(sin(1)*x + 1, x, domain=EX)
assert f.factor_list() == (1, [(f, 1)])
f = x**4 + 1
assert factor(f) == f
assert factor(f, extension=I) == (x**2 - I)*(x**2 + I)
assert factor(f, gaussian=True) == (x**2 - I)*(x**2 + I)
assert factor(
f, extension=sqrt(2)) == (x**2 + sqrt(2)*x + 1)*(x**2 - sqrt(2)*x + 1)
f = x**2 + 2*sqrt(2)*x + 2
assert factor(f, extension=sqrt(2)) == (x + sqrt(2))**2
assert factor(f**3, extension=sqrt(2)) == (x + sqrt(2))**6
assert factor(x**2 - 2*y**2, extension=sqrt(2)) == \
(x + sqrt(2)*y)*(x - sqrt(2)*y)
assert factor(2*x**2 - 4*y**2, extension=sqrt(2)) == \
2*((x + sqrt(2)*y)*(x - sqrt(2)*y))
assert factor(x - 1) == x - 1
assert factor(-x - 1) == -x - 1
assert factor(x - 1) == x - 1
assert factor(6*x - 10) == Mul(2, 3*x - 5, evaluate=False)
assert factor(x**11 + x + 1, modulus=65537, symmetric=True) == \
(x**2 + x + 1)*(x**9 - x**8 + x**6 - x**5 + x**3 - x** 2 + 1)
assert factor(x**11 + x + 1, modulus=65537, symmetric=False) == \
(x**2 + x + 1)*(x**9 + 65536*x**8 + x**6 + 65536*x**5 +
x**3 + 65536*x** 2 + 1)
f = x/pi + x*sin(x)/pi
g = y/(pi**2 + 2*pi + 1) + y*sin(x)/(pi**2 + 2*pi + 1)
assert factor(f) == x*(sin(x) + 1)/pi
assert factor(g) == y*(sin(x) + 1)/(pi + 1)**2
assert factor(Eq(
x**2 + 2*x + 1, x**3 + 1)) == Eq((x + 1)**2, (x + 1)*(x**2 - x + 1))
f = (x**2 - 1)/(x**2 + 4*x + 4)
assert factor(f) == (x + 1)*(x - 1)/(x + 2)**2
assert factor(f, x) == (x + 1)*(x - 1)/(x + 2)**2
f = 3 + x - x*(1 + x) + x**2
assert factor(f) == 3
assert factor(f, x) == 3
assert factor(1/(x**2 + 2*x + 1/x) - 1) == -((1 - x + 2*x**2 +
x**3)/(1 + 2*x**2 + x**3))
assert factor(f, expand=False) == f
raises(PolynomialError, lambda: factor(f, x, expand=False))
raises(FlagError, lambda: factor(x**2 - 1, polys=True))
assert factor([x, Eq(x**2 - y**2, Tuple(x**2 - z**2, 1/x + 1/y))]) == \
[x, Eq((x - y)*(x + y), Tuple((x - z)*(x + z), (x + y)/x/y))]
assert not isinstance(
Poly(x**3 + x + 1).factor_list()[1][0][0], PurePoly) is True
assert isinstance(
PurePoly(x**3 + x + 1).factor_list()[1][0][0], PurePoly) is True
assert factor(sqrt(-x)) == sqrt(-x)
# issue 5917
e = (-2*x*(-x + 1)*(x - 1)*(-x*(-x + 1)*(x - 1) - x*(x - 1)**2)*(x**2*(x -
1) - x*(x - 1) - x) - (-2*x**2*(x - 1)**2 - x*(-x + 1)*(-x*(-x + 1) +
x*(x - 1)))*(x**2*(x - 1)**4 - x*(-x*(-x + 1)*(x - 1) - x*(x - 1)**2)))
assert factor(e) == 0
# deep option
assert factor(sin(x**2 + x) + x, deep=True) == sin(x*(x + 1)) + x
assert factor(sin(x**2 + x)*x, deep=True) == sin(x*(x + 1))*x
assert factor(sqrt(x**2)) == sqrt(x**2)
# issue 13149
assert factor(expand((0.5*x+1)*(0.5*y+1))) == Mul(1.0, 0.5*x + 1.0,
0.5*y + 1.0, evaluate = False)
assert factor(expand((0.5*x+0.5)**2)) == 0.25*(1.0*x + 1.0)**2
def test_factor_large():
f = (x**2 + 4*x + 4)**10000000*(x**2 + 1)*(x**2 + 2*x + 1)**1234567
g = ((x**2 + 2*x + 1)**3000*y**2 + (x**2 + 2*x + 1)**3000*2*y + (
x**2 + 2*x + 1)**3000)
assert factor(f) == (x + 2)**20000000*(x**2 + 1)*(x + 1)**2469134
assert factor(g) == (x + 1)**6000*(y + 1)**2
assert factor_list(
f) == (1, [(x + 1, 2469134), (x + 2, 20000000), (x**2 + 1, 1)])
assert factor_list(g) == (1, [(y + 1, 2), (x + 1, 6000)])
f = (x**2 - y**2)**200000*(x**7 + 1)
g = (x**2 + y**2)**200000*(x**7 + 1)
assert factor(f) == \
(x + 1)*(x - y)**200000*(x + y)**200000*(x**6 - x**5 +
x**4 - x**3 + x**2 - x + 1)
assert factor(g, gaussian=True) == \
(x + 1)*(x - I*y)**200000*(x + I*y)**200000*(x**6 - x**5 +
x**4 - x**3 + x**2 - x + 1)
assert factor_list(f) == \
(1, [(x + 1, 1), (x - y, 200000), (x + y, 200000), (x**6 -
x**5 + x**4 - x**3 + x**2 - x + 1, 1)])
assert factor_list(g, gaussian=True) == \
(1, [(x + 1, 1), (x - I*y, 200000), (x + I*y, 200000), (
x**6 - x**5 + x**4 - x**3 + x**2 - x + 1, 1)])
def test_factor_noeval():
assert factor(6*x - 10) == Mul(2, 3*x - 5, evaluate=False)
assert factor((6*x - 10)/(3*x - 6)) == Mul(S(2)/3, 3*x - 5, 1/(x - 2))
def test_intervals():
assert intervals(0) == []
assert intervals(1) == []
assert intervals(x, sqf=True) == [(0, 0)]
assert intervals(x) == [((0, 0), 1)]
assert intervals(x**128) == [((0, 0), 128)]
assert intervals([x**2, x**4]) == [((0, 0), {0: 2, 1: 4})]
f = Poly((2*x/5 - S(17)/3)*(4*x + S(1)/257))
assert f.intervals(sqf=True) == [(-1, 0), (14, 15)]
assert f.intervals() == [((-1, 0), 1), ((14, 15), 1)]
assert f.intervals(fast=True, sqf=True) == [(-1, 0), (14, 15)]
assert f.intervals(fast=True) == [((-1, 0), 1), ((14, 15), 1)]
assert f.intervals(eps=S(1)/10) == f.intervals(eps=0.1) == \
[((-S(1)/258, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert f.intervals(eps=S(1)/100) == f.intervals(eps=0.01) == \
[((-S(1)/258, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert f.intervals(eps=S(1)/1000) == f.intervals(eps=0.001) == \
[((-S(1)/1002, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert f.intervals(eps=S(1)/10000) == f.intervals(eps=0.0001) == \
[((-S(1)/1028, -S(1)/1028), 1), ((S(85)/6, S(85)/6), 1)]
f = (2*x/5 - S(17)/3)*(4*x + S(1)/257)
assert intervals(f, sqf=True) == [(-1, 0), (14, 15)]
assert intervals(f) == [((-1, 0), 1), ((14, 15), 1)]
assert intervals(f, eps=S(1)/10) == intervals(f, eps=0.1) == \
[((-S(1)/258, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert intervals(f, eps=S(1)/100) == intervals(f, eps=0.01) == \
[((-S(1)/258, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert intervals(f, eps=S(1)/1000) == intervals(f, eps=0.001) == \
[((-S(1)/1002, 0), 1), ((S(85)/6, S(85)/6), 1)]
assert intervals(f, eps=S(1)/10000) == intervals(f, eps=0.0001) == \
[((-S(1)/1028, -S(1)/1028), 1), ((S(85)/6, S(85)/6), 1)]
f = Poly((x**2 - 2)*(x**2 - 3)**7*(x + 1)*(7*x + 3)**3)
assert f.intervals() == \
[((-2, -S(3)/2), 7), ((-S(3)/2, -1), 1),
((-1, -1), 1), ((-1, 0), 3),
((1, S(3)/2), 1), ((S(3)/2, 2), 7)]
assert intervals([x**5 - 200, x**5 - 201]) == \
[((S(75)/26, S(101)/35), {0: 1}), ((S(309)/107, S(26)/9), {1: 1})]
assert intervals([x**5 - 200, x**5 - 201], fast=True) == \
[((S(75)/26, S(101)/35), {0: 1}), ((S(309)/107, S(26)/9), {1: 1})]
assert intervals([x**2 - 200, x**2 - 201]) == \
[((-S(71)/5, -S(85)/6), {1: 1}), ((-S(85)/6, -14), {0: 1}),
((14, S(85)/6), {0: 1}), ((S(85)/6, S(71)/5), {1: 1})]
assert intervals([x + 1, x + 2, x - 1, x + 1, 1, x - 1, x - 1, (x - 2)**2]) == \
[((-2, -2), {1: 1}), ((-1, -1), {0: 1, 3: 1}), ((1, 1), {2:
1, 5: 1, 6: 1}), ((2, 2), {7: 2})]
f, g, h = x**2 - 2, x**4 - 4*x**2 + 4, x - 1
assert intervals(f, inf=S(7)/4, sqf=True) == []
assert intervals(f, inf=S(7)/5, sqf=True) == [(S(7)/5, S(3)/2)]
assert intervals(f, sup=S(7)/4, sqf=True) == [(-2, -1), (1, S(3)/2)]
assert intervals(f, sup=S(7)/5, sqf=True) == [(-2, -1)]
assert intervals(g, inf=S(7)/4) == []
assert intervals(g, inf=S(7)/5) == [((S(7)/5, S(3)/2), 2)]
assert intervals(g, sup=S(7)/4) == [((-2, -1), 2), ((1, S(3)/2), 2)]
assert intervals(g, sup=S(7)/5) == [((-2, -1), 2)]
assert intervals([g, h], inf=S(7)/4) == []
assert intervals([g, h], inf=S(7)/5) == [((S(7)/5, S(3)/2), {0: 2})]
assert intervals([g, h], sup=S(
7)/4) == [((-2, -1), {0: 2}), ((1, 1), {1: 1}), ((1, S(3)/2), {0: 2})]
assert intervals(
[g, h], sup=S(7)/5) == [((-2, -1), {0: 2}), ((1, 1), {1: 1})]
assert intervals([x + 2, x**2 - 2]) == \
[((-2, -2), {0: 1}), ((-2, -1), {1: 1}), ((1, 2), {1: 1})]
assert intervals([x + 2, x**2 - 2], strict=True) == \
[((-2, -2), {0: 1}), ((-S(3)/2, -1), {1: 1}), ((1, 2), {1: 1})]
f = 7*z**4 - 19*z**3 + 20*z**2 + 17*z + 20
assert intervals(f) == []
real_part, complex_part = intervals(f, all=True, sqf=True)
assert real_part == []
assert all(re(a) < re(r) < re(b) and im(
a) < im(r) < im(b) for (a, b), r in zip(complex_part, nroots(f)))
assert complex_part == [(-S(40)/7 - 40*I/7, 0), (-S(40)/7, 40*I/7),
(-40*I/7, S(40)/7), (0, S(40)/7 + 40*I/7)]
real_part, complex_part = intervals(f, all=True, sqf=True, eps=S(1)/10)
assert real_part == []
assert all(re(a) < re(r) < re(b) and im(
a) < im(r) < im(b) for (a, b), r in zip(complex_part, nroots(f)))
raises(ValueError, lambda: intervals(x**2 - 2, eps=10**-100000))
raises(ValueError, lambda: Poly(x**2 - 2).intervals(eps=10**-100000))
raises(
ValueError, lambda: intervals([x**2 - 2, x**2 - 3], eps=10**-100000))
def test_refine_root():
f = Poly(x**2 - 2)
assert f.refine_root(1, 2, steps=0) == (1, 2)
assert f.refine_root(-2, -1, steps=0) == (-2, -1)
assert f.refine_root(1, 2, steps=None) == (1, S(3)/2)
assert f.refine_root(-2, -1, steps=None) == (-S(3)/2, -1)
assert f.refine_root(1, 2, steps=1) == (1, S(3)/2)
assert f.refine_root(-2, -1, steps=1) == (-S(3)/2, -1)
assert f.refine_root(1, 2, steps=1, fast=True) == (1, S(3)/2)
assert f.refine_root(-2, -1, steps=1, fast=True) == (-S(3)/2, -1)
assert f.refine_root(1, 2, eps=S(1)/100) == (S(24)/17, S(17)/12)
assert f.refine_root(1, 2, eps=1e-2) == (S(24)/17, S(17)/12)
raises(PolynomialError, lambda: (f**2).refine_root(1, 2, check_sqf=True))
raises(RefinementFailed, lambda: (f**2).refine_root(1, 2))
raises(RefinementFailed, lambda: (f**2).refine_root(2, 3))
f = x**2 - 2
assert refine_root(f, 1, 2, steps=1) == (1, S(3)/2)
assert refine_root(f, -2, -1, steps=1) == (-S(3)/2, -1)
assert refine_root(f, 1, 2, steps=1, fast=True) == (1, S(3)/2)
assert refine_root(f, -2, -1, steps=1, fast=True) == (-S(3)/2, -1)
assert refine_root(f, 1, 2, eps=S(1)/100) == (S(24)/17, S(17)/12)
assert refine_root(f, 1, 2, eps=1e-2) == (S(24)/17, S(17)/12)
raises(PolynomialError, lambda: refine_root(1, 7, 8, eps=S(1)/100))
raises(ValueError, lambda: Poly(f).refine_root(1, 2, eps=10**-100000))
raises(ValueError, lambda: refine_root(f, 1, 2, eps=10**-100000))
def test_count_roots():
assert count_roots(x**2 - 2) == 2
assert count_roots(x**2 - 2, inf=-oo) == 2
assert count_roots(x**2 - 2, sup=+oo) == 2
assert count_roots(x**2 - 2, inf=-oo, sup=+oo) == 2
assert count_roots(x**2 - 2, inf=-2) == 2
assert count_roots(x**2 - 2, inf=-1) == 1
assert count_roots(x**2 - 2, sup=1) == 1
assert count_roots(x**2 - 2, sup=2) == 2
assert count_roots(x**2 - 2, inf=-1, sup=1) == 0
assert count_roots(x**2 - 2, inf=-2, sup=2) == 2
assert count_roots(x**2 - 2, inf=-1, sup=1) == 0
assert count_roots(x**2 - 2, inf=-2, sup=2) == 2
assert count_roots(x**2 + 2) == 0
assert count_roots(x**2 + 2, inf=-2*I) == 2
assert count_roots(x**2 + 2, sup=+2*I) == 2
assert count_roots(x**2 + 2, inf=-2*I, sup=+2*I) == 2
assert count_roots(x**2 + 2, inf=0) == 0
assert count_roots(x**2 + 2, sup=0) == 0
assert count_roots(x**2 + 2, inf=-I) == 1
assert count_roots(x**2 + 2, sup=+I) == 1
assert count_roots(x**2 + 2, inf=+I/2, sup=+I) == 0
assert count_roots(x**2 + 2, inf=-I, sup=-I/2) == 0
raises(PolynomialError, lambda: count_roots(1))
def test_Poly_root():
f = Poly(2*x**3 - 7*x**2 + 4*x + 4)
assert f.root(0) == -S(1)/2
assert f.root(1) == 2
assert f.root(2) == 2
raises(IndexError, lambda: f.root(3))
assert Poly(x**5 + x + 1).root(0) == rootof(x**3 - x**2 + 1, 0)
def test_real_roots():
assert real_roots(x) == [0]
assert real_roots(x, multiple=False) == [(0, 1)]
assert real_roots(x**3) == [0, 0, 0]
assert real_roots(x**3, multiple=False) == [(0, 3)]
assert real_roots(x*(x**3 + x + 3)) == [rootof(x**3 + x + 3, 0), 0]
assert real_roots(x*(x**3 + x + 3), multiple=False) == [(rootof(
x**3 + x + 3, 0), 1), (0, 1)]
assert real_roots(
x**3*(x**3 + x + 3)) == [rootof(x**3 + x + 3, 0), 0, 0, 0]
assert real_roots(x**3*(x**3 + x + 3), multiple=False) == [(rootof(
x**3 + x + 3, 0), 1), (0, 3)]
f = 2*x**3 - 7*x**2 + 4*x + 4
g = x**3 + x + 1
assert Poly(f).real_roots() == [-S(1)/2, 2, 2]
assert Poly(g).real_roots() == [rootof(g, 0)]
def test_all_roots():
f = 2*x**3 - 7*x**2 + 4*x + 4
g = x**3 + x + 1
assert Poly(f).all_roots() == [-S(1)/2, 2, 2]
assert Poly(g).all_roots() == [rootof(g, 0), rootof(g, 1), rootof(g, 2)]
def test_nroots():
assert Poly(0, x).nroots() == []
assert Poly(1, x).nroots() == []
assert Poly(x**2 - 1, x).nroots() == [-1.0, 1.0]
assert Poly(x**2 + 1, x).nroots() == [-1.0*I, 1.0*I]
roots = Poly(x**2 - 1, x).nroots()
assert roots == [-1.0, 1.0]
roots = Poly(x**2 + 1, x).nroots()
assert roots == [-1.0*I, 1.0*I]
roots = Poly(x**2/3 - S(1)/3, x).nroots()
assert roots == [-1.0, 1.0]
roots = Poly(x**2/3 + S(1)/3, x).nroots()
assert roots == [-1.0*I, 1.0*I]
assert Poly(x**2 + 2*I, x).nroots() == [-1.0 + 1.0*I, 1.0 - 1.0*I]
assert Poly(
x**2 + 2*I, x, extension=I).nroots() == [-1.0 + 1.0*I, 1.0 - 1.0*I]
assert Poly(0.2*x + 0.1).nroots() == [-0.5]
roots = nroots(x**5 + x + 1, n=5)
eps = Float("1e-5")
assert re(roots[0]).epsilon_eq(-0.75487, eps) is S.true
assert im(roots[0]) == 0.0
assert re(roots[1]) == -0.5
assert im(roots[1]).epsilon_eq(-0.86602, eps) is S.true
assert re(roots[2]) == -0.5
assert im(roots[2]).epsilon_eq(+0.86602, eps) is S.true
assert re(roots[3]).epsilon_eq(+0.87743, eps) is S.true
assert im(roots[3]).epsilon_eq(-0.74486, eps) is S.true
assert re(roots[4]).epsilon_eq(+0.87743, eps) is S.true
assert im(roots[4]).epsilon_eq(+0.74486, eps) is S.true
eps = Float("1e-6")
assert re(roots[0]).epsilon_eq(-0.75487, eps) is S.false
assert im(roots[0]) == 0.0
assert re(roots[1]) == -0.5
assert im(roots[1]).epsilon_eq(-0.86602, eps) is S.false
assert re(roots[2]) == -0.5
assert im(roots[2]).epsilon_eq(+0.86602, eps) is S.false
assert re(roots[3]).epsilon_eq(+0.87743, eps) is S.false
assert im(roots[3]).epsilon_eq(-0.74486, eps) is S.false
assert re(roots[4]).epsilon_eq(+0.87743, eps) is S.false
assert im(roots[4]).epsilon_eq(+0.74486, eps) is S.false
raises(DomainError, lambda: Poly(x + y, x).nroots())
raises(MultivariatePolynomialError, lambda: Poly(x + y).nroots())
assert nroots(x**2 - 1) == [-1.0, 1.0]
roots = nroots(x**2 - 1)
assert roots == [-1.0, 1.0]
assert nroots(x + I) == [-1.0*I]
assert nroots(x + 2*I) == [-2.0*I]
raises(PolynomialError, lambda: nroots(0))
# issue 8296
f = Poly(x**4 - 1)
assert f.nroots(2) == [w.n(2) for w in f.all_roots()]
assert str(Poly(x**16 + 32*x**14 + 508*x**12 + 5440*x**10 +
39510*x**8 + 204320*x**6 + 755548*x**4 + 1434496*x**2 +
877969).nroots(2)) == ('[-1.7 - 1.9*I, -1.7 + 1.9*I, -1.7 '
'- 2.5*I, -1.7 + 2.5*I, -1.0*I, 1.0*I, -1.7*I, 1.7*I, -2.8*I, '
'2.8*I, -3.4*I, 3.4*I, 1.7 - 1.9*I, 1.7 + 1.9*I, 1.7 - 2.5*I, '
'1.7 + 2.5*I]')
def test_ground_roots():
f = x**6 - 4*x**4 + 4*x**3 - x**2
assert Poly(f).ground_roots() == {S(1): 2, S(0): 2}
assert ground_roots(f) == {S(1): 2, S(0): 2}
def test_nth_power_roots_poly():
f = x**4 - x**2 + 1
f_2 = (x**2 - x + 1)**2
f_3 = (x**2 + 1)**2
f_4 = (x**2 + x + 1)**2
f_12 = (x - 1)**4
assert nth_power_roots_poly(f, 1) == f
raises(ValueError, lambda: nth_power_roots_poly(f, 0))
raises(ValueError, lambda: nth_power_roots_poly(f, x))
assert factor(nth_power_roots_poly(f, 2)) == f_2
assert factor(nth_power_roots_poly(f, 3)) == f_3
assert factor(nth_power_roots_poly(f, 4)) == f_4
assert factor(nth_power_roots_poly(f, 12)) == f_12
raises(MultivariatePolynomialError, lambda: nth_power_roots_poly(
x + y, 2, x, y))
def test_torational_factor_list():
p = expand(((x**2-1)*(x-2)).subs({x:x*(1 + sqrt(2))}))
assert _torational_factor_list(p, x) == (-2, [
(-x*(1 + sqrt(2))/2 + 1, 1),
(-x*(1 + sqrt(2)) - 1, 1),
(-x*(1 + sqrt(2)) + 1, 1)])
p = expand(((x**2-1)*(x-2)).subs({x:x*(1 + 2**Rational(1, 4))}))
assert _torational_factor_list(p, x) is None
def test_cancel():
assert cancel(0) == 0
assert cancel(7) == 7
assert cancel(x) == x
assert cancel(oo) == oo
assert cancel((2, 3)) == (1, 2, 3)
assert cancel((1, 0), x) == (1, 1, 0)
assert cancel((0, 1), x) == (1, 0, 1)
f, g, p, q = 4*x**2 - 4, 2*x - 2, 2*x + 2, 1
F, G, P, Q = [ Poly(u, x) for u in (f, g, p, q) ]
assert F.cancel(G) == (1, P, Q)
assert cancel((f, g)) == (1, p, q)
assert cancel((f, g), x) == (1, p, q)
assert cancel((f, g), (x,)) == (1, p, q)
assert cancel((F, G)) == (1, P, Q)
assert cancel((f, g), polys=True) == (1, P, Q)
assert cancel((F, G), polys=False) == (1, p, q)
f = (x**2 - 2)/(x + sqrt(2))
assert cancel(f) == f
assert cancel(f, greedy=False) == x - sqrt(2)
f = (x**2 - 2)/(x - sqrt(2))
assert cancel(f) == f
assert cancel(f, greedy=False) == x + sqrt(2)
assert cancel((x**2/4 - 1, x/2 - 1)) == (S(1)/2, x + 2, 1)
assert cancel((x**2 - y)/(x - y)) == 1/(x - y)*(x**2 - y)
assert cancel((x**2 - y**2)/(x - y), x) == x + y
assert cancel((x**2 - y**2)/(x - y), y) == x + y
assert cancel((x**2 - y**2)/(x - y)) == x + y
assert cancel((x**3 - 1)/(x**2 - 1)) == (x**2 + x + 1)/(x + 1)
assert cancel((x**3/2 - S(1)/2)/(x**2 - 1)) == (x**2 + x + 1)/(2*x + 2)
assert cancel((exp(2*x) + 2*exp(x) + 1)/(exp(x) + 1)) == exp(x) + 1
f = Poly(x**2 - a**2, x)
g = Poly(x - a, x)
F = Poly(x + a, x)
G = Poly(1, x)
assert cancel((f, g)) == (1, F, G)
f = x**3 + (sqrt(2) - 2)*x**2 - (2*sqrt(2) + 3)*x - 3*sqrt(2)
g = x**2 - 2
assert cancel((f, g), extension=True) == (1, x**2 - 2*x - 3, x - sqrt(2))
f = Poly(-2*x + 3, x)
g = Poly(-x**9 + x**8 + x**6 - x**5 + 2*x**2 - 3*x + 1, x)
assert cancel((f, g)) == (1, -f, -g)
f = Poly(y, y, domain='ZZ(x)')
g = Poly(1, y, domain='ZZ[x]')
assert f.cancel(
g) == (1, Poly(y, y, domain='ZZ(x)'), Poly(1, y, domain='ZZ(x)'))
assert f.cancel(g, include=True) == (
Poly(y, y, domain='ZZ(x)'), Poly(1, y, domain='ZZ(x)'))
f = Poly(5*x*y + x, y, domain='ZZ(x)')
g = Poly(2*x**2*y, y, domain='ZZ(x)')
assert f.cancel(g, include=True) == (
Poly(5*y + 1, y, domain='ZZ(x)'), Poly(2*x*y, y, domain='ZZ(x)'))
f = -(-2*x - 4*y + 0.005*(z - y)**2)/((z - y)*(-z + y + 2))
assert cancel(f).is_Mul == True
P = tanh(x - 3.0)
Q = tanh(x + 3.0)
f = ((-2*P**2 + 2)*(-P**2 + 1)*Q**2/2 + (-2*P**2 + 2)*(-2*Q**2 + 2)*P*Q - (-2*P**2 + 2)*P**2*Q**2 + (-2*Q**2 + 2)*(-Q**2 + 1)*P**2/2 - (-2*Q**2 + 2)*P**2*Q**2)/(2*sqrt(P**2*Q**2 + 0.0001)) \
+ (-(-2*P**2 + 2)*P*Q**2/2 - (-2*Q**2 + 2)*P**2*Q/2)*((-2*P**2 + 2)*P*Q**2/2 + (-2*Q**2 + 2)*P**2*Q/2)/(2*(P**2*Q**2 + 0.0001)**(S(3)/2))
assert cancel(f).is_Mul == True
# issue 7022
A = Symbol('A', commutative=False)
p1 = Piecewise((A*(x**2 - 1)/(x + 1), x > 1), ((x + 2)/(x**2 + 2*x), True))
p2 = Piecewise((A*(x - 1), x > 1), (1/x, True))
assert cancel(p1) == p2
assert cancel(2*p1) == 2*p2
assert cancel(1 + p1) == 1 + p2
assert cancel((x**2 - 1)/(x + 1)*p1) == (x - 1)*p2
assert cancel((x**2 - 1)/(x + 1) + p1) == (x - 1) + p2
p3 = Piecewise(((x**2 - 1)/(x + 1), x > 1), ((x + 2)/(x**2 + 2*x), True))
p4 = Piecewise(((x - 1), x > 1), (1/x, True))
assert cancel(p3) == p4
assert cancel(2*p3) == 2*p4
assert cancel(1 + p3) == 1 + p4
assert cancel((x**2 - 1)/(x + 1)*p3) == (x - 1)*p4
assert cancel((x**2 - 1)/(x + 1) + p3) == (x - 1) + p4
# issue 9363
M = MatrixSymbol('M', 5, 5)
assert cancel(M[0,0] + 7) == M[0,0] + 7
expr = sin(M[1, 4] + M[2, 1] * 5 * M[4, 0]) - 5 * M[1, 2] / z
assert cancel(expr) == (z*sin(M[1, 4] + M[2, 1] * 5 * M[4, 0]) - 5 * M[1, 2]) / z
def test_reduced():
f = 2*x**4 + y**2 - x**2 + y**3
G = [x**3 - x, y**3 - y]
Q = [2*x, 1]
r = x**2 + y**2 + y
assert reduced(f, G) == (Q, r)
assert reduced(f, G, x, y) == (Q, r)
H = groebner(G)
assert H.reduce(f) == (Q, r)
Q = [Poly(2*x, x, y), Poly(1, x, y)]
r = Poly(x**2 + y**2 + y, x, y)
assert _strict_eq(reduced(f, G, polys=True), (Q, r))
assert _strict_eq(reduced(f, G, x, y, polys=True), (Q, r))
H = groebner(G, polys=True)
assert _strict_eq(H.reduce(f), (Q, r))
f = 2*x**3 + y**3 + 3*y
G = groebner([x**2 + y**2 - 1, x*y - 2])
Q = [x**2 - x*y**3/2 + x*y/2 + y**6/4 - y**4/2 + y**2/4, -y**5/4 + y**3/2 + 3*y/4]
r = 0
assert reduced(f, G) == (Q, r)
assert G.reduce(f) == (Q, r)
assert reduced(f, G, auto=False)[1] != 0
assert G.reduce(f, auto=False)[1] != 0
assert G.contains(f) is True
assert G.contains(f + 1) is False
assert reduced(1, [1], x) == ([1], 0)
raises(ComputationFailed, lambda: reduced(1, [1]))
def test_groebner():
assert groebner([], x, y, z) == []
assert groebner([x**2 + 1, y**4*x + x**3], x, y, order='lex') == [1 + x**2, -1 + y**4]
assert groebner([x**2 + 1, y**4*x + x**3, x*y*z**3], x, y, z, order='grevlex') == [-1 + y**4, z**3, 1 + x**2]
assert groebner([x**2 + 1, y**4*x + x**3], x, y, order='lex', polys=True) == \
[Poly(1 + x**2, x, y), Poly(-1 + y**4, x, y)]
assert groebner([x**2 + 1, y**4*x + x**3, x*y*z**3], x, y, z, order='grevlex', polys=True) == \
[Poly(-1 + y**4, x, y, z), Poly(z**3, x, y, z), Poly(1 + x**2, x, y, z)]
assert groebner([x**3 - 1, x**2 - 1]) == [x - 1]
assert groebner([Eq(x**3, 1), Eq(x**2, 1)]) == [x - 1]
F = [3*x**2 + y*z - 5*x - 1, 2*x + 3*x*y + y**2, x - 3*y + x*z - 2*z**2]
f = z**9 - x**2*y**3 - 3*x*y**2*z + 11*y*z**2 + x**2*z**2 - 5
G = groebner(F, x, y, z, modulus=7, symmetric=False)
assert G == [1 + x + y + 3*z + 2*z**2 + 2*z**3 + 6*z**4 + z**5,
1 + 3*y + y**2 + 6*z**2 + 3*z**3 + 3*z**4 + 3*z**5 + 4*z**6,
1 + 4*y + 4*z + y*z + 4*z**3 + z**4 + z**6,
6 + 6*z + z**2 + 4*z**3 + 3*z**4 + 6*z**5 + 3*z**6 + z**7]
Q, r = reduced(f, G, x, y, z, modulus=7, symmetric=False, polys=True)
assert sum([ q*g for q, g in zip(Q, G.polys)], r) == Poly(f, modulus=7)
F = [x*y - 2*y, 2*y**2 - x**2]
assert groebner(F, x, y, order='grevlex') == \
[y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y]
assert groebner(F, y, x, order='grevlex') == \
[x**3 - 2*x**2, -x**2 + 2*y**2, x*y - 2*y]
assert groebner(F, order='grevlex', field=True) == \
[y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y]
assert groebner([1], x) == [1]
assert groebner([x**2 + 2.0*y], x, y) == [1.0*x**2 + 2.0*y]
raises(ComputationFailed, lambda: groebner([1]))
assert groebner([x**2 - 1, x**3 + 1], method='buchberger') == [x + 1]
assert groebner([x**2 - 1, x**3 + 1], method='f5b') == [x + 1]
raises(ValueError, lambda: groebner([x, y], method='unknown'))
def test_fglm():
F = [a + b + c + d, a*b + a*d + b*c + b*d, a*b*c + a*b*d + a*c*d + b*c*d, a*b*c*d - 1]
G = groebner(F, a, b, c, d, order=grlex)
B = [
4*a + 3*d**9 - 4*d**5 - 3*d,
4*b + 4*c - 3*d**9 + 4*d**5 + 7*d,
4*c**2 + 3*d**10 - 4*d**6 - 3*d**2,
4*c*d**4 + 4*c - d**9 + 4*d**5 + 5*d,
d**12 - d**8 - d**4 + 1,
]
assert groebner(F, a, b, c, d, order=lex) == B
assert G.fglm(lex) == B
F = [9*x**8 + 36*x**7 - 32*x**6 - 252*x**5 - 78*x**4 + 468*x**3 + 288*x**2 - 108*x + 9,
-72*t*x**7 - 252*t*x**6 + 192*t*x**5 + 1260*t*x**4 + 312*t*x**3 - 404*t*x**2 - 576*t*x + \
108*t - 72*x**7 - 256*x**6 + 192*x**5 + 1280*x**4 + 312*x**3 - 576*x + 96]
G = groebner(F, t, x, order=grlex)
B = [
203577793572507451707*t + 627982239411707112*x**7 - 666924143779443762*x**6 - \
10874593056632447619*x**5 + 5119998792707079562*x**4 + 72917161949456066376*x**3 + \
20362663855832380362*x**2 - 142079311455258371571*x + 183756699868981873194,
9*x**8 + 36*x**7 - 32*x**6 - 252*x**5 - 78*x**4 + 468*x**3 + 288*x**2 - 108*x + 9,
]
assert groebner(F, t, x, order=lex) == B
assert G.fglm(lex) == B
F = [x**2 - x - 3*y + 1, -2*x + y**2 + y - 1]
G = groebner(F, x, y, order=lex)
B = [
x**2 - x - 3*y + 1,
y**2 - 2*x + y - 1,
]
assert groebner(F, x, y, order=grlex) == B
assert G.fglm(grlex) == B
def test_is_zero_dimensional():
assert is_zero_dimensional([x, y], x, y) is True
assert is_zero_dimensional([x**3 + y**2], x, y) is False
assert is_zero_dimensional([x, y, z], x, y, z) is True
assert is_zero_dimensional([x, y, z], x, y, z, t) is False
F = [x*y - z, y*z - x, x*y - y]
assert is_zero_dimensional(F, x, y, z) is True
F = [x**2 - 2*x*z + 5, x*y**2 + y*z**3, 3*y**2 - 8*z**2]
assert is_zero_dimensional(F, x, y, z) is True
def test_GroebnerBasis():
F = [x*y - 2*y, 2*y**2 - x**2]
G = groebner(F, x, y, order='grevlex')
H = [y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y]
P = [ Poly(h, x, y) for h in H ]
assert groebner(F + [0], x, y, order='grevlex') == G
assert isinstance(G, GroebnerBasis) is True
assert len(G) == 3
assert G[0] == H[0] and not G[0].is_Poly
assert G[1] == H[1] and not G[1].is_Poly
assert G[2] == H[2] and not G[2].is_Poly
assert G[1:] == H[1:] and not any(g.is_Poly for g in G[1:])
assert G[:2] == H[:2] and not any(g.is_Poly for g in G[1:])
assert G.exprs == H
assert G.polys == P
assert G.gens == (x, y)
assert G.domain == ZZ
assert G.order == grevlex
assert G == H
assert G == tuple(H)
assert G == P
assert G == tuple(P)
assert G != []
G = groebner(F, x, y, order='grevlex', polys=True)
assert G[0] == P[0] and G[0].is_Poly
assert G[1] == P[1] and G[1].is_Poly
assert G[2] == P[2] and G[2].is_Poly
assert G[1:] == P[1:] and all(g.is_Poly for g in G[1:])
assert G[:2] == P[:2] and all(g.is_Poly for g in G[1:])
def test_poly():
assert poly(x) == Poly(x, x)
assert poly(y) == Poly(y, y)
assert poly(x + y) == Poly(x + y, x, y)
assert poly(x + sin(x)) == Poly(x + sin(x), x, sin(x))
assert poly(x + y, wrt=y) == Poly(x + y, y, x)
assert poly(x + sin(x), wrt=sin(x)) == Poly(x + sin(x), sin(x), x)
assert poly(x*y + 2*x*z**2 + 17) == Poly(x*y + 2*x*z**2 + 17, x, y, z)
assert poly(2*(y + z)**2 - 1) == Poly(2*y**2 + 4*y*z + 2*z**2 - 1, y, z)
assert poly(
x*(y + z)**2 - 1) == Poly(x*y**2 + 2*x*y*z + x*z**2 - 1, x, y, z)
assert poly(2*x*(
y + z)**2 - 1) == Poly(2*x*y**2 + 4*x*y*z + 2*x*z**2 - 1, x, y, z)
assert poly(2*(
y + z)**2 - x - 1) == Poly(2*y**2 + 4*y*z + 2*z**2 - x - 1, x, y, z)
assert poly(x*(
y + z)**2 - x - 1) == Poly(x*y**2 + 2*x*y*z + x*z**2 - x - 1, x, y, z)
assert poly(2*x*(y + z)**2 - x - 1) == Poly(2*x*y**2 + 4*x*y*z + 2*
x*z**2 - x - 1, x, y, z)
assert poly(x*y + (x + y)**2 + (x + z)**2) == \
Poly(2*x*z + 3*x*y + y**2 + z**2 + 2*x**2, x, y, z)
assert poly(x*y*(x + y)*(x + z)**2) == \
Poly(x**3*y**2 + x*y**2*z**2 + y*x**2*z**2 + 2*z*x**2*
y**2 + 2*y*z*x**3 + y*x**4, x, y, z)
assert poly(Poly(x + y + z, y, x, z)) == Poly(x + y + z, y, x, z)
assert poly((x + y)**2, x) == Poly(x**2 + 2*x*y + y**2, x, domain=ZZ[y])
assert poly((x + y)**2, y) == Poly(x**2 + 2*x*y + y**2, y, domain=ZZ[x])
assert poly(1, x) == Poly(1, x)
raises(GeneratorsNeeded, lambda: poly(1))
# issue 6184
assert poly(x + y, x, y) == Poly(x + y, x, y)
assert poly(x + y, y, x) == Poly(x + y, y, x)
def test_keep_coeff():
u = Mul(2, x + 1, evaluate=False)
assert _keep_coeff(S(1), x) == x
assert _keep_coeff(S(-1), x) == -x
assert _keep_coeff(S(1.0), x) == 1.0*x
assert _keep_coeff(S(-1.0), x) == -1.0*x
assert _keep_coeff(S(1), 2*x) == 2*x
assert _keep_coeff(S(2), x/2) == x
assert _keep_coeff(S(2), sin(x)) == 2*sin(x)
assert _keep_coeff(S(2), x + 1) == u
assert _keep_coeff(x, 1/x) == 1
assert _keep_coeff(x + 1, S(2)) == u
@XFAIL
def test_poly_matching_consistency():
# Test for this issue:
# https://github.com/sympy/sympy/issues/5514
assert I * Poly(x, x) == Poly(I*x, x)
assert Poly(x, x) * I == Poly(I*x, x)
@XFAIL
def test_issue_5786():
assert expand(factor(expand(
(x - I*y)*(z - I*t)), extension=[I])) == -I*t*x - t*y + x*z - I*y*z
def test_noncommutative():
class foo(Expr):
is_commutative=False
e = x/(x + x*y)
c = 1/( 1 + y)
assert cancel(foo(e)) == foo(c)
assert cancel(e + foo(e)) == c + foo(c)
assert cancel(e*foo(c)) == c*foo(c)
def test_to_rational_coeffs():
assert to_rational_coeffs(
Poly(x**3 + y*x**2 + sqrt(y), x, domain='EX')) is None
def test_factor_terms():
# issue 7067
assert factor_list(x*(x + y)) == (1, [(x, 1), (x + y, 1)])
assert sqf_list(x*(x + y)) == (1, [(x, 1), (x + y, 1)])
def test_as_list():
# issue 14496
assert Poly(x**3 + 2, x, domain='ZZ').as_list() == [1, 0, 0, 2]
assert Poly(x**2 + y + 1, x, y, domain='ZZ').as_list() == [[1], [], [1, 1]]
assert Poly(x**2 + y + 1, x, y, z, domain='ZZ').as_list() == \
[[[1]], [[]], [[1], [1]]]
def test_issue_11198():
assert factor_list(sqrt(2)*x) == (sqrt(2), [(x, 1)])
assert factor_list(sqrt(2)*sin(x), sin(x)) == (sqrt(2), [(sin(x), 1)])
def test_Poly_precision():
# Make sure Poly doesn't lose precision
p = Poly(pi.evalf(100)*x)
assert p.as_expr() == pi.evalf(100)*x
def test_issue_12400():
# Correction of check for negative exponents
assert poly(1/(1+sqrt(2)), x) == \
Poly(1/(1+sqrt(2)), x , domain='EX')
def test_issue_14364():
assert gcd(S(6)*(1 + sqrt(3))/5, S(3)*(1 + sqrt(3))/10) == S(3)/10 * (1 + sqrt(3))
assert gcd(sqrt(5)*S(4)/7, sqrt(5)*S(2)/3) == sqrt(5)*S(2)/21
assert lcm(S(2)/3*sqrt(3), S(5)/6*sqrt(3)) == S(10)*sqrt(3)/3
assert lcm(3*sqrt(3), S(4)/sqrt(3)) == 12*sqrt(3)
assert lcm(S(5)*(1 + 2**(S(1)/3))/6, S(3)*(1 + 2**(S(1)/3))/8) == S(15)/2 * (1 + 2**(S(1)/3))
assert gcd(S(2)/3*sqrt(3), S(5)/6/sqrt(3)) == sqrt(3)/18
assert gcd(S(4)*sqrt(13)/7, S(3)*sqrt(13)/14) == sqrt(13)/14
# gcd_list and lcm_list
assert gcd([S(2)*sqrt(47)/7, S(6)*sqrt(47)/5, S(8)*sqrt(47)/5]) == S(2)*sqrt(47)/35
assert gcd([S(6)*(1 + sqrt(7))/5, S(2)*(1 + sqrt(7))/7, S(4)*(1 + sqrt(7))/13]) == S(2)/455 * (1 + sqrt(7))
assert lcm((S(7)/sqrt(15)/2, S(5)/sqrt(15)/6, S(5)/sqrt(15)/8)) == S(35)/(2*sqrt(15))
assert lcm([S(5)*(2 + 2**(S(5)/7))/6, S(7)*(2 + 2**(S(5)/7))/2, S(13)*(2 + 2**(S(5)/7))/4]) == S(455)/2 * (2 + 2**(S(5)/7))
def test_issue_15669():
x = Symbol("x", positive=True)
expr = (16*x**3/(-x**2 + sqrt(8*x**2 + (x**2 - 2)**2) + 2)**2 -
2*2**(S(4)/5)*x*(-x**2 + sqrt(8*x**2 + (x**2 - 2)**2) + 2)**(S(3)/5) + 10*x)
assert factor(expr, deep=True) == x*(x**2 + 2)
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8243b6dbbc0cacbe5d1ca49d082335581e44a59dc497b93c5b4ede61599d2478
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from sympy import var, sturm, subresultants, prem, pquo
from sympy.matrices import Matrix, eye
from sympy.polys.subresultants_qq_zz import (sylvester, res, res_q, res_z, bezout,
subresultants_sylv, modified_subresultants_sylv,
subresultants_bezout, modified_subresultants_bezout,
process_matrix_output, backward_eye,
sturm_pg, sturm_q, sturm_amv, euclid_pg, euclid_q,
euclid_amv, modified_subresultants_pg, subresultants_pg,
subresultants_amv_q, quo_z, rem_z, subresultants_amv,
modified_subresultants_amv, subresultants_rem,
subresultants_vv, subresultants_vv_2)
def test_sylvester():
x = var('x')
assert sylvester(x**3 -7, 0, x) == sylvester(x**3 -7, 0, x, 1) == Matrix([[0]])
assert sylvester(0, x**3 -7, x) == sylvester(0, x**3 -7, x, 1) == Matrix([[0]])
assert sylvester(x**3 -7, 0, x, 2) == Matrix([[0]])
assert sylvester(0, x**3 -7, x, 2) == Matrix([[0]])
assert sylvester(x**3 -7, 7, x).det() == sylvester(x**3 -7, 7, x, 1).det() == 343
assert sylvester(7, x**3 -7, x).det() == sylvester(7, x**3 -7, x, 1).det() == 343
assert sylvester(x**3 -7, 7, x, 2).det() == -343
assert sylvester(7, x**3 -7, x, 2).det() == 343
assert sylvester(3, 7, x).det() == sylvester(3, 7, x, 1).det() == sylvester(3, 7, x, 2).det() == 1
assert sylvester(3, 0, x).det() == sylvester(3, 0, x, 1).det() == sylvester(3, 0, x, 2).det() == 1
assert sylvester(x - 3, x - 8, x) == sylvester(x - 3, x - 8, x, 1) == sylvester(x - 3, x - 8, x, 2) == Matrix([[1, -3], [1, -8]])
assert sylvester(x**3 - 7*x + 7, 3*x**2 - 7, x) == sylvester(x**3 - 7*x + 7, 3*x**2 - 7, x, 1) == Matrix([[1, 0, -7, 7, 0], [0, 1, 0, -7, 7], [3, 0, -7, 0, 0], [0, 3, 0, -7, 0], [0, 0, 3, 0, -7]])
assert sylvester(x**3 - 7*x + 7, 3*x**2 - 7, x, 2) == Matrix([
[1, 0, -7, 7, 0, 0], [0, 3, 0, -7, 0, 0], [0, 1, 0, -7, 7, 0], [0, 0, 3, 0, -7, 0], [0, 0, 1, 0, -7, 7], [0, 0, 0, 3, 0, -7]])
def test_subresultants_sylv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_sylv(p, q, x) == subresultants(p, q, x)
assert subresultants_sylv(p, q, x)[-1] == res(p, q, x)
assert subresultants_sylv(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_sylv(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_sylv(p, q, x) == euclid_amv(p, q, x)
def test_modified_subresultants_sylv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
amv_factors = [1, 1, -1, 1, -1, 1]
assert modified_subresultants_sylv(p, q, x) == [i*j for i, j in zip(amv_factors, subresultants_amv(p, q, x))]
assert modified_subresultants_sylv(p, q, x)[-1] != res_q(p + x**8, q, x)
assert modified_subresultants_sylv(p, q, x) != sturm_amv(p, q, x)
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert modified_subresultants_sylv(p, q, x) == sturm_amv(p, q, x)
assert modified_subresultants_sylv(-p, q, x) != sturm_amv(-p, q, x)
def test_res():
x = var('x')
assert res(3, 5, x) == 1
def test_res_q():
x = var('x')
assert res_q(3, 5, x) == 1
def test_res_z():
x = var('x')
assert res_z(3, 5, x) == 1
assert res(3, 5, x) == res_q(3, 5, x) == res_z(3, 5, x)
def test_bezout():
x = var('x')
p = -2*x**5+7*x**3+9*x**2-3*x+1
q = -10*x**4+21*x**2+18*x-3
assert bezout(p, q, x, 'bz').det() == sylvester(p, q, x, 2).det()
assert bezout(p, q, x, 'bz').det() != sylvester(p, q, x, 1).det()
assert bezout(p, q, x, 'prs') == backward_eye(5) * bezout(p, q, x, 'bz') * backward_eye(5)
def test_subresultants_bezout():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_bezout(p, q, x) == subresultants(p, q, x)
assert subresultants_bezout(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_bezout(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_bezout(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_bezout(p, q, x) == euclid_amv(p, q, x)
def test_modified_subresultants_bezout():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
amv_factors = [1, 1, -1, 1, -1, 1]
assert modified_subresultants_bezout(p, q, x) == [i*j for i, j in zip(amv_factors, subresultants_amv(p, q, x))]
assert modified_subresultants_bezout(p, q, x)[-1] != sylvester(p + x**8, q, x).det()
assert modified_subresultants_bezout(p, q, x) != sturm_amv(p, q, x)
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert modified_subresultants_bezout(p, q, x) == sturm_amv(p, q, x)
assert modified_subresultants_bezout(-p, q, x) != sturm_amv(-p, q, x)
def test_sturm_pg():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert sturm_pg(p, q, x)[-1] != sylvester(p, q, x, 2).det()
sam_factors = [1, 1, -1, -1, 1, 1]
assert sturm_pg(p, q, x) == [i*j for i,j in zip(sam_factors, euclid_pg(p, q, x))]
p = -9*x**5 - 5*x**3 - 9
q = -45*x**4 - 15*x**2
assert sturm_pg(p, q, x, 1)[-1] == sylvester(p, q, x, 1).det()
assert sturm_pg(p, q, x)[-1] != sylvester(p, q, x, 2).det()
assert sturm_pg(-p, q, x)[-1] == sylvester(-p, q, x, 2).det()
assert sturm_pg(-p, q, x) == modified_subresultants_pg(-p, q, x)
def test_sturm_q():
x = var('x')
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert sturm_q(p, q, x) == sturm(p)
assert sturm_q(-p, -q, x) != sturm(-p)
def test_sturm_amv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert sturm_amv(p, q, x)[-1] != sylvester(p, q, x, 2).det()
sam_factors = [1, 1, -1, -1, 1, 1]
assert sturm_amv(p, q, x) == [i*j for i,j in zip(sam_factors, euclid_amv(p, q, x))]
p = -9*x**5 - 5*x**3 - 9
q = -45*x**4 - 15*x**2
assert sturm_amv(p, q, x, 1)[-1] == sylvester(p, q, x, 1).det()
assert sturm_amv(p, q, x)[-1] != sylvester(p, q, x, 2).det()
assert sturm_amv(-p, q, x)[-1] == sylvester(-p, q, x, 2).det()
assert sturm_pg(-p, q, x) == modified_subresultants_pg(-p, q, x)
def test_euclid_pg():
x = var('x')
p = x**6+x**5-x**4-x**3+x**2-x+1
q = 6*x**5+5*x**4-4*x**3-3*x**2+2*x-1
assert euclid_pg(p, q, x)[-1] == sylvester(p, q, x).det()
assert euclid_pg(p, q, x) == subresultants_pg(p, q, x)
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert euclid_pg(p, q, x)[-1] != sylvester(p, q, x, 2).det()
sam_factors = [1, 1, -1, -1, 1, 1]
assert euclid_pg(p, q, x) == [i*j for i,j in zip(sam_factors, sturm_pg(p, q, x))]
def test_euclid_q():
x = var('x')
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert euclid_q(p, q, x)[-1] == -sturm(p)[-1]
def test_euclid_amv():
x = var('x')
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert euclid_amv(p, q, x)[-1] == sylvester(p, q, x).det()
assert euclid_amv(p, q, x) == subresultants_amv(p, q, x)
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert euclid_amv(p, q, x)[-1] != sylvester(p, q, x, 2).det()
sam_factors = [1, 1, -1, -1, 1, 1]
assert euclid_amv(p, q, x) == [i*j for i,j in zip(sam_factors, sturm_amv(p, q, x))]
def test_modified_subresultants_pg():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
amv_factors = [1, 1, -1, 1, -1, 1]
assert modified_subresultants_pg(p, q, x) == [i*j for i, j in zip(amv_factors, subresultants_pg(p, q, x))]
assert modified_subresultants_pg(p, q, x)[-1] != sylvester(p + x**8, q, x).det()
assert modified_subresultants_pg(p, q, x) != sturm_pg(p, q, x)
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert modified_subresultants_pg(p, q, x) == sturm_pg(p, q, x)
assert modified_subresultants_pg(-p, q, x) != sturm_pg(-p, q, x)
def test_subresultants_pg():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_pg(p, q, x) == subresultants(p, q, x)
assert subresultants_pg(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_pg(p, q, x) != euclid_pg(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_pg(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_pg(p, q, x) == euclid_pg(p, q, x)
def test_subresultants_amv_q():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_amv_q(p, q, x) == subresultants(p, q, x)
assert subresultants_amv_q(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_amv_q(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_amv_q(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_amv(p, q, x) == euclid_amv(p, q, x)
def test_rem_z():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert rem_z(p, -q, x) != prem(p, -q, x)
def test_quo_z():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert quo_z(p, -q, x) != pquo(p, -q, x)
def test_subresultants_amv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_amv(p, q, x) == subresultants(p, q, x)
assert subresultants_amv(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_amv(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_amv(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_amv(p, q, x) == euclid_amv(p, q, x)
def test_modified_subresultants_amv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
amv_factors = [1, 1, -1, 1, -1, 1]
assert modified_subresultants_amv(p, q, x) == [i*j for i, j in zip(amv_factors, subresultants_amv(p, q, x))]
assert modified_subresultants_amv(p, q, x)[-1] != sylvester(p + x**8, q, x).det()
assert modified_subresultants_amv(p, q, x) != sturm_amv(p, q, x)
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert modified_subresultants_amv(p, q, x) == sturm_amv(p, q, x)
assert modified_subresultants_amv(-p, q, x) != sturm_amv(-p, q, x)
def test_subresultants_rem():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_rem(p, q, x) == subresultants(p, q, x)
assert subresultants_rem(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_rem(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_rem(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_rem(p, q, x) == euclid_amv(p, q, x)
def test_subresultants_vv():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_vv(p, q, x) == subresultants(p, q, x)
assert subresultants_vv(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_vv(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_vv(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_vv(p, q, x) == euclid_amv(p, q, x)
def test_subresultants_vv_2():
x = var('x')
p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
assert subresultants_vv_2(p, q, x) == subresultants(p, q, x)
assert subresultants_vv_2(p, q, x)[-1] == sylvester(p, q, x).det()
assert subresultants_vv_2(p, q, x) != euclid_amv(p, q, x)
amv_factors = [1, 1, -1, 1, -1, 1]
assert subresultants_vv_2(p, q, x) == [i*j for i, j in zip(amv_factors, modified_subresultants_amv(p, q, x))]
p = x**3 - 7*x + 7
q = 3*x**2 - 7
assert subresultants_vv_2(p, q, x) == euclid_amv(p, q, x)
|
f9ec93d5e7462f87bfa6edb7749823a2416f69f58aa85f484f3d8b65e6d622e5
|
from sympy import Symbol, sqrt, Derivative, S, Function, exp
from sympy.geometry import Point, Point2D, Line, Circle, Polygon, Segment, convex_hull, intersection, centroid
from sympy.geometry.util import idiff, closest_points, farthest_points, _ordered_points
from sympy.solvers.solvers import solve
from sympy.utilities.pytest import raises
def test_idiff():
x = Symbol('x', real=True)
y = Symbol('y', real=True)
t = Symbol('t', real=True)
f = Function('f')
g = Function('g')
# the use of idiff in ellipse also provides coverage
circ = x**2 + y**2 - 4
ans = -3*x*(x**2 + y**2)/y**5
assert ans == idiff(circ, y, x, 3).simplify()
assert ans == idiff(circ, [y], x, 3).simplify()
assert idiff(circ, y, x, 3).simplify() == ans
explicit = 12*x/sqrt(-x**2 + 4)**5
assert ans.subs(y, solve(circ, y)[0]).equals(explicit)
assert True in [sol.diff(x, 3).equals(explicit) for sol in solve(circ, y)]
assert idiff(x + t + y, [y, t], x) == -Derivative(t, x) - 1
assert idiff(f(x) * exp(f(x)) - x * exp(x), f(x), x) == (x + 1) * exp(x - f(x))/(f(x) + 1)
assert idiff(f(x) - y * exp(x), [f(x), y], x) == (y + Derivative(y, x)) * exp(x)
assert idiff(f(x) - y * exp(x), [y, f(x)], x) == -y + exp(-x) * Derivative(f(x), x)
assert idiff(f(x) - g(x), [f(x), g(x)], x) == Derivative(g(x), x)
def test_intersection():
assert intersection(Point(0, 0)) == []
raises(TypeError, lambda: intersection(Point(0, 0), 3))
assert intersection(
Segment((0, 0), (2, 0)),
Segment((-1, 0), (1, 0)),
Line((0, 0), (0, 1)), pairwise=True) == [
Point(0, 0), Segment((0, 0), (1, 0))]
assert intersection(
Line((0, 0), (0, 1)),
Segment((0, 0), (2, 0)),
Segment((-1, 0), (1, 0)), pairwise=True) == [
Point(0, 0), Segment((0, 0), (1, 0))]
assert intersection(
Line((0, 0), (0, 1)),
Segment((0, 0), (2, 0)),
Segment((-1, 0), (1, 0)),
Line((0, 0), slope=1), pairwise=True) == [
Point(0, 0), Segment((0, 0), (1, 0))]
def test_convex_hull():
raises(TypeError, lambda: convex_hull(Point(0, 0), 3))
points = [(1, -1), (1, -2), (3, -1), (-5, -2), (15, -4)]
assert convex_hull(*points, **dict(polygon=False)) == (
[Point2D(-5, -2), Point2D(1, -1), Point2D(3, -1), Point2D(15, -4)],
[Point2D(-5, -2), Point2D(15, -4)])
def test_centroid():
p = Polygon((0, 0), (10, 0), (10, 10))
q = p.translate(0, 20)
assert centroid(p, q) == Point(20, 40)/3
p = Segment((0, 0), (2, 0))
q = Segment((0, 0), (2, 2))
assert centroid(p, q) == Point(1, -sqrt(2) + 2)
assert centroid(Point(0, 0), Point(2, 0)) == Point(2, 0)/2
assert centroid(Point(0, 0), Point(0, 0), Point(2, 0)) == Point(2, 0)/3
def test_farthest_points_closest_points():
from random import randint
from sympy.utilities.iterables import subsets
for how in (min, max):
if how is min:
func = closest_points
else:
func = farthest_points
raises(ValueError, lambda: func(Point2D(0, 0), Point2D(0, 0)))
# 3rd pt dx is close and pt is closer to 1st pt
p1 = [Point2D(0, 0), Point2D(3, 0), Point2D(1, 1)]
# 3rd pt dx is close and pt is closer to 2nd pt
p2 = [Point2D(0, 0), Point2D(3, 0), Point2D(2, 1)]
# 3rd pt dx is close and but pt is not closer
p3 = [Point2D(0, 0), Point2D(3, 0), Point2D(1, 10)]
# 3rd pt dx is not closer and it's closer to 2nd pt
p4 = [Point2D(0, 0), Point2D(3, 0), Point2D(4, 0)]
# 3rd pt dx is not closer and it's closer to 1st pt
p5 = [Point2D(0, 0), Point2D(3, 0), Point2D(-1, 0)]
# duplicate point doesn't affect outcome
dup = [Point2D(0, 0), Point2D(3, 0), Point2D(3, 0), Point2D(-1, 0)]
# symbolic
x = Symbol('x', positive=True)
s = [Point2D(a) for a in ((x, 1), (x + 3, 2), (x + 2, 2))]
for points in (p1, p2, p3, p4, p5, s, dup):
d = how(i.distance(j) for i, j in subsets(points, 2))
ans = a, b = list(func(*points))[0]
a.distance(b) == d
assert ans == _ordered_points(ans)
# if the following ever fails, the above tests were not sufficient
# and the logical error in the routine should be fixed
points = set()
while len(points) != 7:
points.add(Point2D(randint(1, 100), randint(1, 100)))
points = list(points)
d = how(i.distance(j) for i, j in subsets(points, 2))
ans = a, b = list(func(*points))[0]
a.distance(b) == d
assert ans == _ordered_points(ans)
# equidistant points
a, b, c = (
Point2D(0, 0), Point2D(1, 0), Point2D(S(1)/2, sqrt(3)/2))
ans = set([_ordered_points((i, j))
for i, j in subsets((a, b, c), 2)])
assert closest_points(b, c, a) == ans
assert farthest_points(b, c, a) == ans
# unique to farthest
points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)]
assert farthest_points(*points) == set(
[(Point2D(-5, 2), Point2D(15, 4))])
points = [(1, -1), (1, -2), (3, -1), (-5, -2), (15, -4)]
assert farthest_points(*points) == set(
[(Point2D(-5, -2), Point2D(15, -4))])
assert farthest_points((1, 1), (0, 0)) == set(
[(Point2D(0, 0), Point2D(1, 1))])
raises(ValueError, lambda: farthest_points((1, 1)))
|
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