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| """Implementation of :class:`PythonRationalField` class. """ | |
| from sympy.polys.domains.groundtypes import PythonInteger, PythonRational, SymPyRational | |
| from sympy.polys.domains.rationalfield import RationalField | |
| from sympy.polys.polyerrors import CoercionFailed | |
| from sympy.utilities import public | |
| class PythonRationalField(RationalField): | |
| """Rational field based on :ref:`MPQ`. | |
| This will be used as :ref:`QQ` if ``gmpy`` and ``gmpy2`` are not | |
| installed. Elements are instances of :ref:`MPQ`. | |
| """ | |
| dtype = PythonRational | |
| zero = dtype(0) | |
| one = dtype(1) | |
| alias = 'QQ_python' | |
| def __init__(self): | |
| pass | |
| def get_ring(self): | |
| """Returns ring associated with ``self``. """ | |
| from sympy.polys.domains import PythonIntegerRing | |
| return PythonIntegerRing() | |
| def to_sympy(self, a): | |
| """Convert `a` to a SymPy object. """ | |
| return SymPyRational(a.numerator, a.denominator) | |
| def from_sympy(self, a): | |
| """Convert SymPy's Rational to `dtype`. """ | |
| if a.is_Rational: | |
| return PythonRational(a.p, a.q) | |
| elif a.is_Float: | |
| from sympy.polys.domains import RR | |
| p, q = RR.to_rational(a) | |
| return PythonRational(int(p), int(q)) | |
| else: | |
| raise CoercionFailed("expected `Rational` object, got %s" % a) | |
| def from_ZZ_python(K1, a, K0): | |
| """Convert a Python `int` object to `dtype`. """ | |
| return PythonRational(a) | |
| def from_QQ_python(K1, a, K0): | |
| """Convert a Python `Fraction` object to `dtype`. """ | |
| return a | |
| def from_ZZ_gmpy(K1, a, K0): | |
| """Convert a GMPY `mpz` object to `dtype`. """ | |
| return PythonRational(PythonInteger(a)) | |
| def from_QQ_gmpy(K1, a, K0): | |
| """Convert a GMPY `mpq` object to `dtype`. """ | |
| return PythonRational(PythonInteger(a.numer()), | |
| PythonInteger(a.denom())) | |
| def from_RealField(K1, a, K0): | |
| """Convert a mpmath `mpf` object to `dtype`. """ | |
| p, q = K0.to_rational(a) | |
| return PythonRational(int(p), int(q)) | |
| def numer(self, a): | |
| """Returns numerator of `a`. """ | |
| return a.numerator | |
| def denom(self, a): | |
| """Returns denominator of `a`. """ | |
| return a.denominator | |