200 lines
6.0 KiB
Python
200 lines
6.0 KiB
Python
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"""Implementation of :class:`PolynomialRing` class. """
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from sympy.polys.domains.ring import Ring
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from sympy.polys.domains.compositedomain import CompositeDomain
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from sympy.polys.polyerrors import CoercionFailed, GeneratorsError
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from sympy.utilities import public
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@public
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class PolynomialRing(Ring, CompositeDomain):
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"""A class for representing multivariate polynomial rings. """
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is_PolynomialRing = is_Poly = True
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has_assoc_Ring = True
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has_assoc_Field = True
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def __init__(self, domain_or_ring, symbols=None, order=None):
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from sympy.polys.rings import PolyRing
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if isinstance(domain_or_ring, PolyRing) and symbols is None and order is None:
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ring = domain_or_ring
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else:
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ring = PolyRing(symbols, domain_or_ring, order)
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self.ring = ring
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self.dtype = ring.dtype
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self.gens = ring.gens
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self.ngens = ring.ngens
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self.symbols = ring.symbols
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self.domain = ring.domain
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if symbols:
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if ring.domain.is_Field and ring.domain.is_Exact and len(symbols)==1:
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self.is_PID = True
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# TODO: remove this
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self.dom = self.domain
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def new(self, element):
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return self.ring.ring_new(element)
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@property
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def zero(self):
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return self.ring.zero
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@property
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def one(self):
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return self.ring.one
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@property
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def order(self):
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return self.ring.order
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def __str__(self):
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return str(self.domain) + '[' + ','.join(map(str, self.symbols)) + ']'
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def __hash__(self):
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return hash((self.__class__.__name__, self.dtype.ring, self.domain, self.symbols))
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def __eq__(self, other):
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"""Returns `True` if two domains are equivalent. """
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return isinstance(other, PolynomialRing) and \
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(self.dtype.ring, self.domain, self.symbols) == \
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(other.dtype.ring, other.domain, other.symbols)
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def is_unit(self, a):
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"""Returns ``True`` if ``a`` is a unit of ``self``"""
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if not a.is_ground:
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return False
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K = self.domain
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return K.is_unit(K.convert_from(a, self))
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def canonical_unit(self, a):
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u = self.domain.canonical_unit(a.LC)
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return self.ring.ground_new(u)
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def to_sympy(self, a):
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"""Convert `a` to a SymPy object. """
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return a.as_expr()
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def from_sympy(self, a):
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"""Convert SymPy's expression to `dtype`. """
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return self.ring.from_expr(a)
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def from_ZZ(K1, a, K0):
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"""Convert a Python `int` object to `dtype`. """
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return K1(K1.domain.convert(a, K0))
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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 K1(K1.domain.convert(a, K0))
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def from_QQ(K1, a, K0):
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"""Convert a Python `Fraction` object to `dtype`. """
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return K1(K1.domain.convert(a, K0))
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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 K1(K1.domain.convert(a, K0))
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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 K1(K1.domain.convert(a, K0))
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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 K1(K1.domain.convert(a, K0))
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def from_GaussianIntegerRing(K1, a, K0):
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"""Convert a `GaussianInteger` object to `dtype`. """
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return K1(K1.domain.convert(a, K0))
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def from_GaussianRationalField(K1, a, K0):
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"""Convert a `GaussianRational` object to `dtype`. """
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return K1(K1.domain.convert(a, K0))
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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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return K1(K1.domain.convert(a, K0))
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def from_ComplexField(K1, a, K0):
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"""Convert a mpmath `mpf` object to `dtype`. """
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return K1(K1.domain.convert(a, K0))
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def from_AlgebraicField(K1, a, K0):
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"""Convert an algebraic number to ``dtype``. """
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if K1.domain != K0:
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a = K1.domain.convert_from(a, K0)
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if a is not None:
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return K1.new(a)
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def from_PolynomialRing(K1, a, K0):
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"""Convert a polynomial to ``dtype``. """
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try:
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return a.set_ring(K1.ring)
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except (CoercionFailed, GeneratorsError):
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return None
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def from_FractionField(K1, a, K0):
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"""Convert a rational function to ``dtype``. """
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if K1.domain == K0:
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return K1.ring.from_list([a])
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q, r = K0.numer(a).div(K0.denom(a))
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if r.is_zero:
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return K1.from_PolynomialRing(q, K0.field.ring.to_domain())
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else:
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return None
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def from_GlobalPolynomialRing(K1, a, K0):
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"""Convert from old poly ring to ``dtype``. """
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if K1.symbols == K0.gens:
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ad = a.to_dict()
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if K1.domain != K0.domain:
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ad = {m: K1.domain.convert(c) for m, c in ad.items()}
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return K1(ad)
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elif a.is_ground and K0.domain == K1:
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return K1.convert_from(a.to_list()[0], K0.domain)
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def get_field(self):
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"""Returns a field associated with `self`. """
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return self.ring.to_field().to_domain()
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def is_positive(self, a):
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"""Returns True if `LC(a)` is positive. """
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return self.domain.is_positive(a.LC)
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def is_negative(self, a):
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"""Returns True if `LC(a)` is negative. """
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return self.domain.is_negative(a.LC)
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def is_nonpositive(self, a):
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"""Returns True if `LC(a)` is non-positive. """
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return self.domain.is_nonpositive(a.LC)
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def is_nonnegative(self, a):
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"""Returns True if `LC(a)` is non-negative. """
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return self.domain.is_nonnegative(a.LC)
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def gcdex(self, a, b):
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"""Extended GCD of `a` and `b`. """
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return a.gcdex(b)
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def gcd(self, a, b):
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"""Returns GCD of `a` and `b`. """
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return a.gcd(b)
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def lcm(self, a, b):
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"""Returns LCM of `a` and `b`. """
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return a.lcm(b)
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def factorial(self, a):
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"""Returns factorial of `a`. """
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return self.dtype(self.domain.factorial(a))
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