"""Implementation of :class:`ExpressionDomain` class. """
from __future__ import print_function, division
from sympy.core import sympify, SympifyError
from sympy.polys.domains.characteristiczero import CharacteristicZero
from sympy.polys.domains.field import Field
from sympy.polys.domains.simpledomain import SimpleDomain
from sympy.polys.polyutils import PicklableWithSlots
from sympy.utilities import public
[docs]@public
class ExpressionDomain(Field, CharacteristicZero, SimpleDomain):
"""A class for arbitrary expressions. """
is_SymbolicDomain = is_EX = True
[docs] class Expression(PicklableWithSlots):
"""An arbitrary expression. """
__slots__ = ['ex']
def __init__(self, ex):
if not isinstance(ex, self.__class__):
self.ex = sympify(ex)
else:
self.ex = ex.ex
def __repr__(f):
return 'EX(%s)' % repr(f.ex)
def __str__(f):
return 'EX(%s)' % str(f.ex)
def __hash__(self):
return hash((self.__class__.__name__, self.ex))
def as_expr(f):
return f.ex
def numer(f):
return f.__class__(f.ex.as_numer_denom()[0])
def denom(f):
return f.__class__(f.ex.as_numer_denom()[1])
def simplify(f, ex):
return f.__class__(ex.cancel())
def __abs__(f):
return f.__class__(abs(f.ex))
def __neg__(f):
return f.__class__(-f.ex)
def _to_ex(f, g):
try:
return f.__class__(g)
except SympifyError:
return None
def __add__(f, g):
g = f._to_ex(g)
if g is not None:
return f.simplify(f.ex + g.ex)
else:
return NotImplemented
def __radd__(f, g):
return f.simplify(f.__class__(g).ex + f.ex)
def __sub__(f, g):
g = f._to_ex(g)
if g is not None:
return f.simplify(f.ex - g.ex)
else:
return NotImplemented
def __rsub__(f, g):
return f.simplify(f.__class__(g).ex - f.ex)
def __mul__(f, g):
g = f._to_ex(g)
if g is not None:
return f.simplify(f.ex*g.ex)
else:
return NotImplemented
def __rmul__(f, g):
return f.simplify(f.__class__(g).ex*f.ex)
def __pow__(f, n):
n = f._to_ex(n)
if n is not None:
return f.simplify(f.ex**n.ex)
else:
return NotImplemented
def __truediv__(f, g):
g = f._to_ex(g)
if g is not None:
return f.simplify(f.ex/g.ex)
else:
return NotImplemented
def __rtruediv__(f, g):
return f.simplify(f.__class__(g).ex/f.ex)
__div__ = __truediv__
__rdiv__ = __rtruediv__
def __eq__(f, g):
return f.ex == f.__class__(g).ex
def __ne__(f, g):
return not f == g
def __nonzero__(f):
return f.ex != 0
__bool__ = __nonzero__
def gcd(f, g):
from sympy.polys import gcd
return f.__class__(gcd(f.ex, f.__class__(g).ex))
def lcm(f, g):
from sympy.polys import lcm
return f.__class__(lcm(f.ex, f.__class__(g).ex))
dtype = Expression
zero = Expression(0)
one = Expression(1)
rep = 'EX'
has_assoc_Ring = False
has_assoc_Field = True
def __init__(self):
pass
[docs] def to_sympy(self, a):
"""Convert ``a`` to a SymPy object. """
return a.as_expr()
[docs] def from_sympy(self, a):
"""Convert SymPy's expression to ``dtype``. """
return self.dtype(a)
[docs] def from_ZZ_python(K1, a, K0):
"""Convert a Python ``int`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_QQ_python(K1, a, K0):
"""Convert a Python ``Fraction`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_ZZ_gmpy(K1, a, K0):
"""Convert a GMPY ``mpz`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_QQ_gmpy(K1, a, K0):
"""Convert a GMPY ``mpq`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_RealField(K1, a, K0):
"""Convert a mpmath ``mpf`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_PolynomialRing(K1, a, K0):
"""Convert a ``DMP`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_FractionField(K1, a, K0):
"""Convert a ``DMF`` object to ``dtype``. """
return K1(K0.to_sympy(a))
[docs] def from_ExpressionDomain(K1, a, K0):
"""Convert a ``EX`` object to ``dtype``. """
return a
[docs] def get_ring(self):
"""Returns a ring associated with ``self``. """
return self # XXX: EX is not a ring but we don't have much choice here.
[docs] def get_field(self):
"""Returns a field associated with ``self``. """
return self
[docs] def is_positive(self, a):
"""Returns True if ``a`` is positive. """
return a.ex.as_coeff_mul()[0].is_positive
[docs] def is_negative(self, a):
"""Returns True if ``a`` is negative. """
return a.ex.as_coeff_mul()[0].is_negative
[docs] def is_nonpositive(self, a):
"""Returns True if ``a`` is non-positive. """
return a.ex.as_coeff_mul()[0].is_nonpositive
[docs] def is_nonnegative(self, a):
"""Returns True if ``a`` is non-negative. """
return a.ex.as_coeff_mul()[0].is_nonnegative
[docs] def numer(self, a):
"""Returns numerator of ``a``. """
return a.numer()
[docs] def denom(self, a):
"""Returns denominator of ``a``. """
return a.denom()
def gcd(self, a, b):
return a.gcd(b)
def lcm(self, a, b):
return a.lcm(b)
