Spaces:
Sleeping
Sleeping
File size: 1,962 Bytes
6a86ad5 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 |
from sympy.core import AtomicExpr, Symbol, S
from sympy.core.sympify import _sympify
from sympy.printing.pretty.stringpict import prettyForm
from sympy.printing.precedence import PRECEDENCE
class BaseScalar(AtomicExpr):
"""
A coordinate symbol/base scalar.
Ideally, users should not instantiate this class.
"""
def __new__(cls, index, system, pretty_str=None, latex_str=None):
from sympy.vector.coordsysrect import CoordSys3D
if pretty_str is None:
pretty_str = "x{}".format(index)
elif isinstance(pretty_str, Symbol):
pretty_str = pretty_str.name
if latex_str is None:
latex_str = "x_{}".format(index)
elif isinstance(latex_str, Symbol):
latex_str = latex_str.name
index = _sympify(index)
system = _sympify(system)
obj = super().__new__(cls, index, system)
if not isinstance(system, CoordSys3D):
raise TypeError("system should be a CoordSys3D")
if index not in range(0, 3):
raise ValueError("Invalid index specified.")
# The _id is used for equating purposes, and for hashing
obj._id = (index, system)
obj._name = obj.name = system._name + '.' + system._variable_names[index]
obj._pretty_form = '' + pretty_str
obj._latex_form = latex_str
obj._system = system
return obj
is_commutative = True
is_symbol = True
@property
def free_symbols(self):
return {self}
_diff_wrt = True
def _eval_derivative(self, s):
if self == s:
return S.One
return S.Zero
def _latex(self, printer=None):
return self._latex_form
def _pretty(self, printer=None):
return prettyForm(self._pretty_form)
precedence = PRECEDENCE['Atom']
@property
def system(self):
return self._system
def _sympystr(self, printer):
return self._name
|