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