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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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