def test_PolyRing___getitem__():
R, x,y,z = ring("x,y,z", ZZ)
assert R[0:] == PolyRing("x,y,z", ZZ, lex)
assert R[1:] == PolyRing("y,z", ZZ, lex)
assert R[2:] == PolyRing("z", ZZ, lex)
assert R[3:] == ZZ
def __init__(self, symbols, domain, order):
from sympy.polys.rings import PolyRing
self.ring = PolyRing(symbols, domain, order)
self.dtype = FracElement
self.symbols = self.ring.symbols
self.ngens = len(self.symbols)
self.domain = self.ring.domain
self.order = self.ring.order
self.gens = self._gens()
def test_PolyElement_drop():
R, x,y,z = ring("x,y,z", ZZ)
assert R(1).drop(0).ring == PolyRing("y,z", ZZ, lex)
assert R(1).drop(0).drop(0).ring == PolyRing("z", ZZ, lex)
assert isinstance(R(1).drop(0).drop(0).drop(0), R.dtype) is False
raises(ValueError, lambda: z.drop(0).drop(0).drop(0))
raises(ValueError, lambda: x.drop(0))
def test_PolyRing_is_():
R = PolyRing("x", QQ, lex)
assert R.is_univariate is True
assert R.is_multivariate is False
R = PolyRing("x,y,z", QQ, lex)
assert R.is_univariate is False
assert R.is_multivariate is True
def test_sring():
x, y, z, t = symbols("x,y,z,t")
R = PolyRing("x,y,z", ZZ, lex)
assert sring(x + 2 * y + 3 * z) == (R, R.x + 2 * R.y + 3 * R.z)
R = PolyRing("x,y,z", QQ, lex)
assert sring(x + 2 * y + z / 3) == (R, R.x + 2 * R.y + R.z / 3)
assert sring([x, 2 * y, z / 3]) == (R, [R.x, 2 * R.y, R.z / 3])
Rt = PolyRing("t", ZZ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + 2 * t * y + 3 * t**2 * z, x, y,
z) == (R, R.x + 2 * Rt.t * R.y + 3 * Rt.t**2 * R.z)
Rt = PolyRing("t", QQ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + t * y / 2 + t**2 * z / 3, x, y,
z) == (R, R.x + Rt.t * R.y / 2 + Rt.t**2 * R.z / 3)
Rt = FracField("t", ZZ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + 2 * y / t + t**2 * z / 3, x, y,
z) == (R, R.x + 2 * R.y / Rt.t + Rt.t**2 * R.z / 3)
r = sqrt(2) - sqrt(3)
R, a = sring(r, extension=True)
assert R.domain == QQ.algebraic_field(r)
assert R.gens == ()
assert a == R.domain.from_sympy(r)
def __init__(self, symbols, domain, order):
from sympy.polys.rings import PolyRing
self.ring = PolyRing(symbols, domain, order)
self.dtype = FracElement
self.symbols = self.ring.symbols
self.ngens = len(self.symbols)
self.domain = self.ring.domain
self.order = self.ring.order
self.gens = self._gens()
def __new__(cls, iterative, F, n, *gens, **args):
"""Compute a reduced Groebner basis for a system of polynomials. """
options.allowed_flags(args, ['polys', 'method'])
try:
polys, opt = parallel_poly_from_expr(F, *gens, **args)
except PolificationFailed as exc:
raise ComputationFailed('groebner', len(F), exc)
from sympy.polys.rings import PolyRing
ring = PolyRing(opt.gens, opt.domain, opt.order)
polys = [ring.from_dict(poly.rep.to_dict()) for poly in polys if poly]
if iterative:
G = iter_groebner(polys, n, ring, method=opt.method
) #Assumes last element is the "new" polynomial
else:
G = _groebner(polys, ring, method=opt.method)
G = [Poly._from_dict(g, opt) for g in G]
return cls._new(G, opt)
def test_pickling_polys_rings():
# NOTE: can't use protocols < 2 because we have to execute __new__ to
# make sure caching of rings works properly.
from sympy.polys.rings import PolyRing
ring = PolyRing("x,y,z", ZZ, lex)
for c in (PolyRing, ring):
check(c, exclude=[0, 1])
for c in (ring.dtype, ring.one):
check(c, exclude=[0, 1], check_attr=False) # TODO: Py3k
def test_PolyRing___init__():
x, y, z = map(Symbol, "xyz")
assert len(PolyRing("x,y,z", ZZ, lex).gens) == 3
assert len(PolyRing(x, ZZ, lex).gens) == 1
assert len(PolyRing(("x", "y", "z"), ZZ, lex).gens) == 3
assert len(PolyRing((x, y, z), ZZ, lex).gens) == 3
raises(GeneratorsNeeded, lambda: PolyRing([], ZZ, lex))
raises(GeneratorsError, lambda: PolyRing(0, ZZ, lex))
def test_PolyRing_drop():
R, x,y,z = ring("x,y,z", ZZ)
assert R.drop(x) == PolyRing("y,z", ZZ, lex)
assert R.drop(y) == PolyRing("x,z", ZZ, lex)
assert R.drop(z) == PolyRing("x,y", ZZ, lex)
assert R.drop(0) == PolyRing("y,z", ZZ, lex)
assert R.drop(0).drop(0) == PolyRing("z", ZZ, lex)
assert R.drop(0).drop(0).drop(0) == ZZ
assert R.drop(1) == PolyRing("x,z", ZZ, lex)
assert R.drop(2) == PolyRing("x,y", ZZ, lex)
assert R.drop(2).drop(1) == PolyRing("x", ZZ, lex)
assert R.drop(2).drop(1).drop(0) == ZZ
raises(ValueError, lambda: R.drop(3))
raises(ValueError, lambda: R.drop(x).drop(y))
def __init__(self, domain_or_ring, symbols=None, order=None):
from sympy.polys.rings import PolyRing
if isinstance(domain_or_ring, PolyRing) and symbols is None and order is None:
ring = domain_or_ring
else:
ring = PolyRing(symbols, domain_or_ring, order)
self.ring = ring
self.dtype = ring.dtype
self.gens = ring.gens
self.ngens = ring.ngens
self.symbols = ring.symbols
self.domain = ring.domain
# TODO: remove this
self.dom = self.domain
def __new__(cls, symbols, domain, order=lex):
from sympy.polys.rings import PolyRing
ring = PolyRing(symbols, domain, order)
symbols = ring.symbols
ngens = ring.ngens
domain = ring.domain
order = ring.order
_hash_tuple = (cls.__name__, symbols, ngens, domain, order)
obj = _field_cache.get(_hash_tuple)
if obj is None:
obj = object.__new__(cls)
obj._hash_tuple = _hash_tuple
obj._hash = hash(_hash_tuple)
obj.ring = ring
obj.dtype = type("FracElement", (FracElement, ), {"field": obj})
obj.symbols = symbols
obj.ngens = ngens
obj.domain = domain
obj.order = order
obj.zero = obj.dtype(ring.zero)
obj.one = obj.dtype(ring.one)
obj.gens = obj._gens()
for symbol, generator in zip(obj.symbols, obj.gens):
if isinstance(symbol, Symbol):
name = symbol.name
if not hasattr(obj, name):
setattr(obj, name, generator)
_field_cache[_hash_tuple] = obj
return obj
def test_sring():
x, y, z, t = symbols("x,y,z,t")
R = PolyRing("x,y,z", ZZ, lex)
assert sring(x + 2*y + 3*z) == (R, R.x + 2*R.y + 3*R.z)
R = PolyRing("x,y,z", QQ, lex)
assert sring(x + 2*y + z/3) == (R, R.x + 2*R.y + R.z/3)
assert sring([x, 2*y, z/3]) == (R, [R.x, 2*R.y, R.z/3])
Rt = PolyRing("t", ZZ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + 2*t*y + 3*t**2*z, x, y, z) == (R, R.x + 2*Rt.t*R.y + 3*Rt.t**2*R.z)
Rt = PolyRing("t", QQ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + t*y/2 + t**2*z/3, x, y, z) == (R, R.x + Rt.t*R.y/2 + Rt.t**2*R.z/3)
Rt = FracField("t", ZZ, lex)
R = PolyRing("x,y,z", Rt, lex)
assert sring(x + 2*y/t + t**2*z/3, x, y, z) == (R, R.x + 2*R.y/Rt.t + Rt.t**2*R.z/3)
def __init__(self, domain_or_ring, symbols=None, order=None):
from sympy.polys.rings import PolyRing
if isinstance(domain_or_ring, PolyRing) and symbols is None and order is None:
ring = domain_or_ring
else:
ring = PolyRing(symbols, domain_or_ring, order)
self.ring = ring
self.dtype = ring.dtype
self.gens = ring.gens
self.ngens = ring.ngens
self.symbols = ring.symbols
self.domain = ring.domain
if symbols:
if ring.domain.is_Field and ring.domain.is_Exact and len(symbols)==1:
self.is_PID = True
# TODO: remove this
self.dom = self.domain
def to_ring(self):
from sympy.polys.rings import PolyRing
return PolyRing(self.symbols, self.domain, self.order)
def poly_ring(self, *symbols): # TODO:, order=lex):
"""Returns a polynomial ring, i.e. `K[X]`. """
from sympy.polys.rings import PolyRing
return PolyRing(symbols, self.field, order).to_domain()
def test_PolyRing___init__():
x, y, z, t = map(Symbol, "xyzt")
assert len(PolyRing("x,y,z", ZZ, lex).gens) == 3
assert len(PolyRing(x, ZZ, lex).gens) == 1
assert len(PolyRing(("x", "y", "z"), ZZ, lex).gens) == 3
assert len(PolyRing((x, y, z), ZZ, lex).gens) == 3
raises(GeneratorsNeeded, lambda: PolyRing([], ZZ, lex))
raises(GeneratorsError, lambda: PolyRing(0, ZZ, lex))
assert PolyRing("x", ZZ[t], lex).domain == ZZ[t]
assert PolyRing("x", 'ZZ[t]', lex).domain == ZZ[t]
assert PolyRing("x", PolyRing("t", ZZ, lex), lex).domain == ZZ[t]
raises(GeneratorsError, lambda: PolyRing("x", PolyRing("x", ZZ, lex), lex))
_lex = Symbol("lex")
assert PolyRing("x", ZZ, lex).order == lex
assert PolyRing("x", ZZ, _lex).order == lex
assert PolyRing("x", ZZ, 'lex').order == lex
R1 = PolyRing("x,y", ZZ, lex)
R2 = PolyRing("x,y", ZZ, lex)
R3 = PolyRing("x,y,z", ZZ, lex)
assert R1.x == R1.gens[0]
assert R1.y == R1.gens[1]
assert R1.x == R2.x
assert R1.y == R2.y
assert R1.x != R3.x
assert R1.y != R3.y
def _integrate(field=None):
irreducibles = set()
atans = set()
pairs = set()
for poly in reducibles:
for z in poly.free_symbols:
if z in V:
break # should this be: `irreducibles |= \
else: # set(root_factors(poly, z, filter=field))`
continue # and the line below deleted?
# |
# V
irreducibles |= set(root_factors(poly, z, filter=field))
log_part, atan_part = [], []
x, y = symbols('x y', cls=Wild, exclude=[I])
for poly in list(irreducibles):
m = poly.match(x + I*y)
if m[y] == 0: # No coefficient of I
continue
pairs.add((m[x], m[y])) # It is enough to save the coefficients
irreducibles.remove(poly)
while pairs:
x, y = pairs.pop()
if (x,-y) in pairs:
pairs.remove((x,-y))
# Choosing b with no minus sign
if y.could_extract_minus_sign():
y = -y
irreducibles.add(x*x + y*y)
atans.add(atan(x/y))
else:
irreducibles.add(x + I*y)
B = _symbols('B', len(irreducibles))
C = _symbols('C', len(atans))
# Note: the ordering matters here
for poly, b in reversed(list(ordered(zip(irreducibles, B)))):
if poly.has(*V):
poly_coeffs.append(b)
log_part.append(b * log(poly))
for poly, c in reversed(list(ordered(zip(atans, C)))):
if poly.has(*V):
poly_coeffs.append(c)
atan_part.append(c * poly)
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancellation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part) + Add(*atan_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(poly_coeffs) | set(V)
non_syms = set([])
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(poly_coeffs, ground)
ring = PolyRing(V, coeff_ring)
try:
numer = ring.from_expr(raw_numer)
except ValueError:
raise PolynomialError
solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
if solution is None:
return None
else:
return candidate.subs(solution).subs(
list(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
def _integrate(field=None):
irreducibles = set()
for poly in reducibles:
for z in poly.free_symbols:
if z in V:
break # should this be: `irreducibles |= \
else: # set(root_factors(poly, z, filter=field))`
continue # and the line below deleted?
# |
# V
irreducibles |= set(root_factors(poly, z, filter=field))
log_coeffs, log_part = [], []
B = _symbols('B', len(irreducibles))
# Note: the ordering matters here
for poly, b in reversed(list(ordered(zip(irreducibles, B)))):
if poly.has(*V):
poly_coeffs.append(b)
log_part.append(b * log(poly))
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancelation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(poly_coeffs) | set(V)
non_syms = set([])
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(poly_coeffs, ground)
ring = PolyRing(V, coeff_ring)
numer = ring.from_expr(raw_numer)
solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
if solution is None:
return None
else:
return candidate.subs(solution).subs(
list(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
class FracField(DefaultPrinting):
def __init__(self, symbols, domain, order):
from sympy.polys.rings import PolyRing
self.ring = PolyRing(symbols, domain, order)
self.dtype = FracElement
self.symbols = self.ring.symbols
self.ngens = len(self.symbols)
self.domain = self.ring.domain
self.order = self.ring.order
self.gens = self._gens()
def _gens(self):
"""Return a list of polynomial generators. """
return tuple([ self.dtype(self, gen) for gen in self.ring.gens ])
_hash = None
def __hash__(self):
_hash = self._hash
if _hash is None:
self._hash = _hash = hash((self.symbols, self.domain, self.order))
return _hash
def __eq__(self, other):
return isinstance(other, FracField) and self.ring == other.ring
def __ne__(self, other):
return not self.__eq__(other)
def new(self, numer, denom=None):
return self.dtype(self, numer, denom)
def domain_new(self, element):
return self.domain.convert(element)
def ground_new(self, element):
try:
return self.new(self.ring.ground_new(element))
except CoercionFailed:
domain = self.domain
if domain.has_Ring and domain.has_assoc_Field:
ground_field = domain.get_field()
element = ground_field.convert(element)
numer = ground_field.numer(element)
denom = ground_field.denom(element)
return self.new(numer, denom)
else:
raise
def field_new(self, element):
if isinstance(element, FracElement):
if self == element.field:
return element
else:
raise NotImplementedError("conversion")
elif isinstance(element, PolyElement):
if self.ring == element.ring:
return self.new(element)
else:
raise NotImplementedError("conversion")
elif isinstance(element, tuple) and len(element) == 2:
numer, denom = map(self.ring.ring_new, element)
return self.new(numer, denom)
elif isinstance(element, basestring):
raise NotImplementedError("parsing")
elif isinstance(element, Expr):
return self.from_expr(element)
else:
return self.ground_new(element)
__call__ = field_new
def _rebuild_expr(self, expr, mapping):
domain = self.domain
def _rebuild(expr):
generator = mapping.get(expr)
if generator is not None:
return generator
elif expr.is_Add:
return reduce(add, map(_rebuild, expr.args))
elif expr.is_Mul:
return reduce(mul, map(_rebuild, expr.args))
elif expr.is_Pow and expr.exp.is_Integer:
return _rebuild(expr.base)**int(expr.exp)
else:
try:
return domain.convert(expr)
except CoercionFailed:
if domain.has_Ring and domain.has_assoc_Field:
return domain.get_field().convert(expr)
else:
raise
return _rebuild(sympify(expr))
def from_expr(self, expr):
mapping = dict(zip(self.symbols, self.gens))
try:
frac = self._rebuild_expr(expr, mapping)
except CoercionFailed:
raise ValueError("expected an expression convertible to a rational function in %s, got %s" % (self, expr))
else:
return self.field_new(frac)
@property
def zero(self):
return self.new(self.ring.zero)
@property
def one(self):
return self.new(self.ring.one)
def to_domain(self):
from sympy.polys.domains.fractionfield import FractionField
return FractionField(self)
def to_ring(self):
from sympy.polys.rings import PolyRing
return PolyRing(self.symbols, self.domain, self.order)
def _integrate(field=None):
irreducibles = set()
for poly in reducibles:
for z in poly.atoms(Symbol):
if z in V:
break
else:
continue
irreducibles |= set(root_factors(poly, z, filter=field))
log_coeffs, log_part = [], []
B = _symbols('B', len(irreducibles))
for i, poly in enumerate(irreducibles):
if poly.has(*V):
log_coeffs.append(B[i])
log_part.append(log_coeffs[-1] * log(poly))
coeffs = poly_coeffs + log_coeffs
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancelation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(coeffs) | set(V)
non_syms = set([])
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(coeffs, ground)
ring = PolyRing(V, coeff_ring)
numer = ring.from_expr(raw_numer)
solution = solve_lin_sys(numer.coeffs(), coeff_ring)
if solution is None:
return None
else:
solution = [ (k.as_expr(), v.as_expr()) for k, v in solution.items() ]
return candidate.subs(solution).subs(list(zip(coeffs, [S.Zero]*len(coeffs))))
def _integrate(field=None):
irreducibles = set()
atans = set()
pairs = set()
for poly in reducibles:
for z in poly.free_symbols:
if z in V:
break # should this be: `irreducibles |= \
else: # set(root_factors(poly, z, filter=field))`
continue # and the line below deleted?
# |
# V
irreducibles |= set(root_factors(poly, z, filter=field))
log_part, atan_part = [], []
for poly in list(irreducibles):
m = collect(poly, I, evaluate=False)
y = m.get(I, S.Zero)
if y:
x = m.get(S.One, S.Zero)
if x.has(I) or y.has(I):
continue # nontrivial x + I*y
pairs.add((x, y))
irreducibles.remove(poly)
while pairs:
x, y = pairs.pop()
if (x, -y) in pairs:
pairs.remove((x, -y))
# Choosing b with no minus sign
if y.could_extract_minus_sign():
y = -y
irreducibles.add(x*x + y*y)
atans.add(atan(x/y))
else:
irreducibles.add(x + I*y)
B = _symbols('B', len(irreducibles))
C = _symbols('C', len(atans))
# Note: the ordering matters here
for poly, b in reversed(list(ordered(zip(irreducibles, B)))):
if poly.has(*V):
poly_coeffs.append(b)
log_part.append(b * log(poly))
for poly, c in reversed(list(ordered(zip(atans, C)))):
if poly.has(*V):
poly_coeffs.append(c)
atan_part.append(c * poly)
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancellation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part) + Add(*atan_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(poly_coeffs) | set(V)
non_syms = set([])
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(poly_coeffs, ground)
ring = PolyRing(V, coeff_ring)
try:
numer = ring.from_expr(raw_numer)
except ValueError:
raise PolynomialError
solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
if solution is None:
return None
else:
return candidate.subs(solution).subs(
list(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
def _integrate(field=None):
atans = set()
pairs = set()
if field == 'Q':
irreducibles = set(reducibles)
else:
setV = set(V)
irreducibles = set()
for poly in ordered(reducibles):
zV = setV & set(iterfreeargs(poly))
for z in ordered(zV):
s = set(root_factors(poly, z, filter=field))
irreducibles |= s
break
log_part, atan_part = [], []
for poly in ordered(irreducibles):
m = collect(poly, I, evaluate=False)
y = m.get(I, S.Zero)
if y:
x = m.get(S.One, S.Zero)
if x.has(I) or y.has(I):
continue # nontrivial x + I*y
pairs.add((x, y))
irreducibles.remove(poly)
while pairs:
x, y = pairs.pop()
if (x, -y) in pairs:
pairs.remove((x, -y))
# Choosing b with no minus sign
if y.could_extract_minus_sign():
y = -y
irreducibles.add(x*x + y*y)
atans.add(atan(x/y))
else:
irreducibles.add(x + I*y)
B = _symbols('B', len(irreducibles))
C = _symbols('C', len(atans))
# Note: the ordering matters here
for poly, b in reversed(list(zip(ordered(irreducibles), B))):
if poly.has(*V):
poly_coeffs.append(b)
log_part.append(b * log(poly))
for poly, c in reversed(list(zip(ordered(atans), C))):
if poly.has(*V):
poly_coeffs.append(c)
atan_part.append(c * poly)
# TODO: Currently it's better to use symbolic expressions here instead
# of rational functions, because it's simpler and FracElement doesn't
# give big speed improvement yet. This is because cancellation is slow
# due to slow polynomial GCD algorithms. If this gets improved then
# revise this code.
candidate = poly_part/poly_denom + Add(*log_part) + Add(*atan_part)
h = F - _derivation(candidate) / denom
raw_numer = h.as_numer_denom()[0]
# Rewrite raw_numer as a polynomial in K[coeffs][V] where K is a field
# that we have to determine. We can't use simply atoms() because log(3),
# sqrt(y) and similar expressions can appear, leading to non-trivial
# domains.
syms = set(poly_coeffs) | set(V)
non_syms = set()
def find_non_syms(expr):
if expr.is_Integer or expr.is_Rational:
pass # ignore trivial numbers
elif expr in syms:
pass # ignore variables
elif not expr.has_free(*syms):
non_syms.add(expr)
elif expr.is_Add or expr.is_Mul or expr.is_Pow:
list(map(find_non_syms, expr.args))
else:
# TODO: Non-polynomial expression. This should have been
# filtered out at an earlier stage.
raise PolynomialError
try:
find_non_syms(raw_numer)
except PolynomialError:
return None
else:
ground, _ = construct_domain(non_syms, field=True)
coeff_ring = PolyRing(poly_coeffs, ground)
ring = PolyRing(V, coeff_ring)
try:
numer = ring.from_expr(raw_numer)
except ValueError:
raise PolynomialError
solution = solve_lin_sys(numer.coeffs(), coeff_ring, _raw=False)
if solution is None:
return None
else:
return candidate.xreplace(solution).xreplace(
dict(zip(poly_coeffs, [S.Zero]*len(poly_coeffs))))
class FracField(DefaultPrinting):
def __init__(self, symbols, domain, order):
from sympy.polys.rings import PolyRing
self.ring = PolyRing(symbols, domain, order)
self.dtype = FracElement
self.symbols = self.ring.symbols
self.ngens = len(self.symbols)
self.domain = self.ring.domain
self.order = self.ring.order
self.gens = self._gens()
def _gens(self):
"""Return a list of polynomial generators. """
return tuple([self.dtype(self, gen) for gen in self.ring.gens])
_hash = None
def __hash__(self):
_hash = self._hash
if _hash is None:
self._hash = _hash = hash((self.symbols, self.domain, self.order))
return _hash
def __eq__(self, other):
return isinstance(other, FracField) and self.ring == other.ring
def __ne__(self, other):
return not self.__eq__(other)
def new(self, numer, denom=None):
return self.dtype(self, numer, denom)
def domain_new(self, element):
return self.domain.convert(element)
def ground_new(self, element):
try:
return self.new(self.ring.ground_new(element))
except CoercionFailed:
domain = self.domain
if domain.has_Ring and domain.has_assoc_Field:
ground_field = domain.get_field()
element = ground_field.convert(element)
numer = ground_field.numer(element)
denom = ground_field.denom(element)
return self.new(numer, denom)
else:
raise
def field_new(self, element):
if isinstance(element, FracElement):
if self == element.field:
return element
else:
raise NotImplementedError("conversion")
elif isinstance(element, PolyElement):
if self.ring == element.ring:
return self.new(element)
else:
raise NotImplementedError("conversion")
elif isinstance(element, tuple) and len(element) == 2:
numer, denom = map(self.ring.ring_new, element)
return self.new(numer, denom)
elif isinstance(element, basestring):
raise NotImplementedError("parsing")
elif isinstance(element, Expr):
return self.from_expr(element)
else:
return self.ground_new(element)
__call__ = field_new
def _rebuild_expr(self, expr, mapping):
domain = self.domain
def _rebuild(expr):
generator = mapping.get(expr)
if generator is not None:
return generator
elif expr.is_Add:
return reduce(add, map(_rebuild, expr.args))
elif expr.is_Mul:
return reduce(mul, map(_rebuild, expr.args))
elif expr.is_Pow and expr.exp.is_Integer:
return _rebuild(expr.base) ** int(expr.exp)
else:
try:
return domain.convert(expr)
except CoercionFailed:
if domain.has_Ring and domain.has_assoc_Field:
return domain.get_field().convert(expr)
else:
raise
return _rebuild(sympify(expr))
def from_expr(self, expr):
mapping = dict(zip(self.symbols, self.gens))
try:
frac = self._rebuild_expr(expr, mapping)
except CoercionFailed:
raise ValueError("expected an expression convertible to a rational function in %s, got %s" % (self, expr))
else:
return self.field_new(frac)
@property
def zero(self):
return self.new(self.ring.zero)
@property
def one(self):
return self.new(self.ring.one)
def to_domain(self):
from sympy.polys.domains.fractionfield import FractionField
return FractionField(self)
def to_ring(self):
from sympy.polys.rings import PolyRing
return PolyRing(self.symbols, self.domain, self.order)