232 lines
5.9 KiB
Python
232 lines
5.9 KiB
Python
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"""Implementation of :class:`IntegerRing` class. """
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from sympy.external.gmpy import MPZ, HAS_GMPY
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from sympy.polys.domains.groundtypes import (
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SymPyInteger,
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factorial,
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gcdex, gcd, lcm, sqrt,
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)
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from sympy.polys.domains.characteristiczero import CharacteristicZero
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from sympy.polys.domains.ring import Ring
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from sympy.polys.domains.simpledomain import SimpleDomain
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from sympy.polys.polyerrors import CoercionFailed
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from sympy.utilities import public
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import math
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@public
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class IntegerRing(Ring, CharacteristicZero, SimpleDomain):
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r"""The domain ``ZZ`` representing the integers `\mathbb{Z}`.
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The :py:class:`IntegerRing` class represents the ring of integers as a
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:py:class:`~.Domain` in the domain system. :py:class:`IntegerRing` is a
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super class of :py:class:`PythonIntegerRing` and
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:py:class:`GMPYIntegerRing` one of which will be the implementation for
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:ref:`ZZ` depending on whether or not ``gmpy`` or ``gmpy2`` is installed.
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See also
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========
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Domain
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"""
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rep = 'ZZ'
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alias = 'ZZ'
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dtype = MPZ
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zero = dtype(0)
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one = dtype(1)
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tp = type(one)
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is_IntegerRing = is_ZZ = True
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is_Numerical = True
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is_PID = True
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has_assoc_Ring = True
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has_assoc_Field = True
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def __init__(self):
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"""Allow instantiation of this domain. """
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def to_sympy(self, a):
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"""Convert ``a`` to a SymPy object. """
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return SymPyInteger(int(a))
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def from_sympy(self, a):
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"""Convert SymPy's Integer to ``dtype``. """
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if a.is_Integer:
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return MPZ(a.p)
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elif a.is_Float and int(a) == a:
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return MPZ(int(a))
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else:
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raise CoercionFailed("expected an integer, got %s" % a)
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def get_field(self):
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r"""Return the associated field of fractions :ref:`QQ`
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Returns
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=======
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:ref:`QQ`:
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The associated field of fractions :ref:`QQ`, a
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:py:class:`~.Domain` representing the rational numbers
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`\mathbb{Q}`.
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Examples
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========
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>>> from sympy import ZZ
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>>> ZZ.get_field()
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QQ
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"""
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from sympy.polys.domains import QQ
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return QQ
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def algebraic_field(self, *extension, alias=None):
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r"""Returns an algebraic field, i.e. `\mathbb{Q}(\alpha, \ldots)`.
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Parameters
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==========
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*extension : One or more :py:class:`~.Expr`.
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Generators of the extension. These should be expressions that are
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algebraic over `\mathbb{Q}`.
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alias : str, :py:class:`~.Symbol`, None, optional (default=None)
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If provided, this will be used as the alias symbol for the
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primitive element of the returned :py:class:`~.AlgebraicField`.
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Returns
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=======
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:py:class:`~.AlgebraicField`
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A :py:class:`~.Domain` representing the algebraic field extension.
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Examples
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========
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>>> from sympy import ZZ, sqrt
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>>> ZZ.algebraic_field(sqrt(2))
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QQ<sqrt(2)>
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"""
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return self.get_field().algebraic_field(*extension, alias=alias)
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def from_AlgebraicField(K1, a, K0):
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"""Convert a :py:class:`~.ANP` object to :ref:`ZZ`.
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See :py:meth:`~.Domain.convert`.
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"""
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if a.is_ground:
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return K1.convert(a.LC(), K0.dom)
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def log(self, a, b):
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r"""Logarithm of *a* to the base *b*.
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Parameters
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==========
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a: number
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b: number
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Returns
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=======
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$\\lfloor\log(a, b)\\rfloor$:
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Floor of the logarithm of *a* to the base *b*
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Examples
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========
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>>> from sympy import ZZ
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>>> ZZ.log(ZZ(8), ZZ(2))
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3
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>>> ZZ.log(ZZ(9), ZZ(2))
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3
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Notes
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=====
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This function uses ``math.log`` which is based on ``float`` so it will
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fail for large integer arguments.
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"""
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return self.dtype(math.log(int(a), b))
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def from_FF(K1, a, K0):
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"""Convert ``ModularInteger(int)`` to GMPY's ``mpz``. """
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return MPZ(a.to_int())
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def from_FF_python(K1, a, K0):
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"""Convert ``ModularInteger(int)`` to GMPY's ``mpz``. """
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return MPZ(a.to_int())
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def from_ZZ(K1, a, K0):
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"""Convert Python's ``int`` to GMPY's ``mpz``. """
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return MPZ(a)
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def from_ZZ_python(K1, a, K0):
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"""Convert Python's ``int`` to GMPY's ``mpz``. """
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return MPZ(a)
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def from_QQ(K1, a, K0):
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"""Convert Python's ``Fraction`` to GMPY's ``mpz``. """
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if a.denominator == 1:
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return MPZ(a.numerator)
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def from_QQ_python(K1, a, K0):
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"""Convert Python's ``Fraction`` to GMPY's ``mpz``. """
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if a.denominator == 1:
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return MPZ(a.numerator)
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def from_FF_gmpy(K1, a, K0):
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"""Convert ``ModularInteger(mpz)`` to GMPY's ``mpz``. """
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return a.to_int()
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def from_ZZ_gmpy(K1, a, K0):
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"""Convert GMPY's ``mpz`` to GMPY's ``mpz``. """
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return a
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def from_QQ_gmpy(K1, a, K0):
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"""Convert GMPY ``mpq`` to GMPY's ``mpz``. """
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if a.denominator == 1:
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return a.numerator
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def from_RealField(K1, a, K0):
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"""Convert mpmath's ``mpf`` to GMPY's ``mpz``. """
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p, q = K0.to_rational(a)
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if q == 1:
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return MPZ(p)
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def from_GaussianIntegerRing(K1, a, K0):
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if a.y == 0:
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return a.x
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def gcdex(self, a, b):
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"""Compute extended GCD of ``a`` and ``b``. """
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h, s, t = gcdex(a, b)
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if HAS_GMPY:
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return s, t, h
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else:
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return h, s, t
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def gcd(self, a, b):
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"""Compute GCD of ``a`` and ``b``. """
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return gcd(a, b)
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def lcm(self, a, b):
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"""Compute LCM of ``a`` and ``b``. """
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return lcm(a, b)
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def sqrt(self, a):
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"""Compute square root of ``a``. """
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return sqrt(a)
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def factorial(self, a):
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"""Compute factorial of ``a``. """
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return factorial(a)
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ZZ = IntegerRing()
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