def test_benchmark_coloring():
V = range(1, 12 + 1)
E = [(1, 2), (2, 3), (1, 4), (1, 6), (1, 12), (2, 5), (2, 7), (3, 8),
(3, 10), (4, 11), (4, 9), (5, 6), (6, 7), (7, 8), (8, 9), (9, 10),
(10, 11), (11, 12), (5, 12), (5, 9), (6, 10), (7, 11), (8, 12),
(3, 4)]
R, V = xring(["x%d" % v for v in V], QQ, lex)
E = [(V[i - 1], V[j - 1]) for i, j in E]
x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12 = V
I3 = [x**3 - 1 for x in V]
Ig = [x**2 + x * y + y**2 for x, y in E]
I = I3 + Ig
assert groebner(I[:-1], R) == [
x1 + x11 + x12,
x2 - x11,
x3 - x12,
x4 - x12,
x5 + x11 + x12,
x6 - x11,
x7 - x12,
x8 + x11 + x12,
x9 - x11,
x10 + x11 + x12,
x11**2 + x11 * x12 + x12**2,
x12**3 - 1,
]
assert groebner(I, R) == [1]
def test_benchmark_coloring():
V = range(1, 12 + 1)
E = [(1, 2), (2, 3), (1, 4), (1, 6), (1, 12), (2, 5), (2, 7), (3, 8), (3, 10),
(4, 11), (4, 9), (5, 6), (6, 7), (7, 8), (8, 9), (9, 10), (10, 11),
(11, 12), (5, 12), (5, 9), (6, 10), (7, 11), (8, 12), (3, 4)]
R, V = xring([ "x%d" % v for v in V ], QQ, lex)
E = [(V[i - 1], V[j - 1]) for i, j in E]
x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12 = V
I3 = [x**3 - 1 for x in V]
Ig = [x**2 + x*y + y**2 for x, y in E]
I = I3 + Ig
assert groebner(I[:-1], R) == [
x1 + x11 + x12,
x2 - x11,
x3 - x12,
x4 - x12,
x5 + x11 + x12,
x6 - x11,
x7 - x12,
x8 + x11 + x12,
x9 - x11,
x10 + x11 + x12,
x11**2 + x11*x12 + x12**2,
x12**3 - 1,
]
assert groebner(I, R) == [1]
def test_PolyElement_diff():
R, X = xring("x:11", QQ)
f = QQ(288,5)*X[0]**8*X[1]**6*X[4]**3*X[10]**2 + 8*X[0]**2*X[2]**3*X[4]**3 +2*X[0]**2 - 2*X[1]**2
assert f.diff(X[0]) == QQ(2304,5)*X[0]**7*X[1]**6*X[4]**3*X[10]**2 + 16*X[0]*X[2]**3*X[4]**3 + 4*X[0]
assert f.diff(X[4]) == QQ(864,5)*X[0]**8*X[1]**6*X[4]**2*X[10]**2 + 24*X[0]**2*X[2]**3*X[4]**2
assert f.diff(X[10]) == QQ(576,5)*X[0]**8*X[1]**6*X[4]**3*X[10]
def test_dmp_factor_list():
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(0) == (ZZ(0), [])
assert R.dmp_factor_list(7) == (7, [])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(0) == (QQ(0), [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
Rt, t = ring("t", ZZ)
R, x, y = ring("x,y", Rt)
assert R.dmp_factor_list(0) == (0, [])
assert R.dmp_factor_list(7) == (ZZ(7), [])
Rt, t = ring("t", QQ)
R, x, y = ring("x,y", Rt)
assert R.dmp_factor_list(0) == (0, [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list_include(0) == [(0, 1)]
assert R.dmp_factor_list_include(7) == [(7, 1)]
R, X = xring("x:200", ZZ)
f, g = X[0]**2 + 2*X[0] + 1, X[0] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
f, g = X[-1]**2 + 2*X[-1] + 1, X[-1] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
R, x = ring("x", ZZ)
assert R.dmp_factor_list(x**2 + 2*x + 1) == (1, [(x + 1, 2)])
R, x = ring("x", QQ)
assert R.dmp_factor_list(QQ(1,2)*x**2 + x + QQ(1,2)) == (QQ(1,2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(x**2 + 2*x + 1) == (1, [(x + 1, 2)])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(QQ(1,2)*x**2 + x + QQ(1,2)) == (QQ(1,2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
f = 4*x**2*y + 4*x*y**2
assert R.dmp_factor_list(f) == \
(4, [(y, 1),
(x, 1),
(x + y, 1)])
assert R.dmp_factor_list_include(f) == \
[(4*y, 1),
(x, 1),
(x + y, 1)]
R, x, y = ring("x,y", QQ)
f = QQ(1,2)*x**2*y + QQ(1,2)*x*y**2
assert R.dmp_factor_list(f) == \
(QQ(1,2), [(y, 1),
(x, 1),
(x + y, 1)])
R, x, y = ring("x,y", RR)
f = 2.0*x**2 - 8.0*y**2
assert R.dmp_factor_list(f) == \
(RR(2.0), [(1.0*x - 2.0*y, 1),
(1.0*x + 2.0*y, 1)])
f = 6.7225336055071*x**2*y**2 - 10.6463972754741*x*y - 0.33469524022264
coeff, factors = R.dmp_factor_list(f)
assert coeff == RR(1.0) and len(factors) == 1 and factors[0][0].almosteq(f, 1e-10) and factors[0][1] == 1
Rt, t = ring("t", ZZ)
R, x, y = ring("x,y", Rt)
f = 4*t*x**2 + 4*t**2*x
assert R.dmp_factor_list(f) == \
(4*t, [(x, 1),
(x + t, 1)])
Rt, t = ring("t", QQ)
R, x, y = ring("x,y", Rt)
f = QQ(1, 2)*t*x**2 + QQ(1, 2)*t**2*x
assert R.dmp_factor_list(f) == \
(QQ(1, 2)*t, [(x, 1),
(x + t, 1)])
R, x, y = ring("x,y", FF(2))
raises(NotImplementedError, lambda: R.dmp_factor_list(x**2 + y**2))
R, x, y = ring("x,y", EX)
raises(DomainError, lambda: R.dmp_factor_list(EX(sin(1))))
def test_dmp_factor_list():
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(0) == (ZZ(0), [])
assert R.dmp_factor_list(7) == (7, [])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(0) == (QQ(0), [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
Rt, t = ring("t", ZZ)
R, x, y = ring("x,y", Rt)
assert R.dmp_factor_list(0) == (0, [])
assert R.dmp_factor_list(7) == (ZZ(7), [])
Rt, t = ring("t", QQ)
R, x, y = ring("x,y", Rt)
assert R.dmp_factor_list(0) == (0, [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list_include(0) == [(0, 1)]
assert R.dmp_factor_list_include(7) == [(7, 1)]
R, X = xring("x:200", ZZ)
f, g = X[0]**2 + 2*X[0] + 1, X[0] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
f, g = X[-1]**2 + 2*X[-1] + 1, X[-1] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
R, x = ring("x", ZZ)
assert R.dmp_factor_list(x**2 + 2*x + 1) == (1, [(x + 1, 2)])
R, x = ring("x", QQ)
assert R.dmp_factor_list(QQ(1,2)*x**2 + x + QQ(1,2)) == (QQ(1,2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(x**2 + 2*x + 1) == (1, [(x + 1, 2)])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(QQ(1,2)*x**2 + x + QQ(1,2)) == (QQ(1,2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
f = 4*x**2*y + 4*x*y**2
assert R.dmp_factor_list(f) == \
(4, [(y, 1),
(x, 1),
(x + y, 1)])
assert R.dmp_factor_list_include(f) == \
[(4*y, 1),
(x, 1),
(x + y, 1)]
R, x, y = ring("x,y", QQ)
f = QQ(1,2)*x**2*y + QQ(1,2)*x*y**2
assert R.dmp_factor_list(f) == \
(QQ(1,2), [(y, 1),
(x, 1),
(x + y, 1)])
R, x, y = ring("x,y", RR)
f = 2.0*x**2 - 8.0*y**2
assert R.dmp_factor_list(f) == \
(RR(2.0), [(1.0*x - 2.0*y, 1),
(1.0*x + 2.0*y, 1)])
f = 6.7225336055071*x**2*y**2 - 10.6463972754741*x*y - 0.33469524022264
coeff, factors = R.dmp_factor_list(f)
assert coeff == RR(1.0) and len(factors) == 1 and factors[0][0].almosteq(f, 1e-10) and factors[0][1] == 1
Rt, t = ring("t", ZZ)
R, x, y = ring("x,y", Rt)
f = 4*t*x**2 + 4*t**2*x
assert R.dmp_factor_list(f) == \
(4*t, [(x, 1),
(x + t, 1)])
Rt, t = ring("t", QQ)
R, x, y = ring("x,y", Rt)
f = QQ(1, 2)*t*x**2 + QQ(1, 2)*t**2*x
assert R.dmp_factor_list(f) == \
(QQ(1, 2)*t, [(x, 1),
(x + t, 1)])
R, x, y = ring("x,y", FF(2))
raises(NotImplementedError, lambda: R.dmp_factor_list(x**2 + y**2))
R, x, y = ring("x,y", EX)
raises(DomainError, lambda: R.dmp_factor_list(EX(sin(1))))
def reduce(self, expr, auto=True):
"""
Reduces a polynomial modulo a Groebner basis.
Given a polynomial ``f`` and a set of polynomials ``G = (g_1, ..., g_n)``,
computes a set of quotients ``q = (q_1, ..., q_n)`` and the remainder ``r``
such that ``f = q_1*f_1 + ... + q_n*f_n + r``, where ``r`` vanishes or ``r``
is a completely reduced polynomial with respect to ``G``.
Examples
========
>>> from sympy import groebner, expand
>>> from sympy.abc import x, y
>>> f = 2*x**4 - x**2 + y**3 + y**2
>>> G = groebner([x**3 - x, y**3 - y])
>>> G.reduce(f)
([2*x, 1], x**2 + y**2 + y)
>>> Q, r = _
>>> expand(sum(q*g for q, g in zip(Q, G)) + r)
2*x**4 - x**2 + y**3 + y**2
>>> _ == f
True
"""
poly = Poly._from_expr(expr, self._options)
polys = [poly] + list(self._basis)
opt = self._options
domain = opt.domain
retract = False
if auto and domain.is_Ring and not domain.is_Field:
opt = opt.clone(dict(domain=domain.get_field()))
retract = True
from sympy.polys.rings import xring
_ring, _ = xring(opt.gens, opt.domain, opt.order)
for i, poly in enumerate(polys):
poly = poly.set_domain(opt.domain).rep.to_dict()
polys[i] = _ring.from_dict(poly)
Q, r = polys[0].div(polys[1:])
Q = [Poly._from_dict(dict(q), opt) for q in Q]
r = Poly._from_dict(dict(r), opt)
if retract:
try:
_Q, _r = [q.to_ring() for q in Q], r.to_ring()
except CoercionFailed:
pass
else:
Q, r = _Q, _r
if not opt.polys:
return [q.as_expr() for q in Q], r.as_expr()
else:
return Q, r
def fglm(self, order):
"""
Convert a Groebner basis from one ordering to another.
The FGLM algorithm converts reduced Groebner bases of zero-dimensional
ideals from one ordering to another. This method is often used when it
is infeasible to compute a Groebner basis with respect to a particular
ordering directly.
Examples
========
>>> from sympy.abc import x, y
>>> from sympy import groebner
>>> F = [x**2 - 3*y - x + 1, y**2 - 2*x + y - 1]
>>> G = groebner(F, x, y, order='grlex')
>>> list(G.fglm('lex'))
[2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7]
>>> list(groebner(F, x, y, order='lex'))
[2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7]
References
==========
J.C. Faugere, P. Gianni, D. Lazard, T. Mora (1994). Efficient
Computation of Zero-dimensional Groebner Bases by Change of
Ordering
"""
opt = self._options
src_order = opt.order
dst_order = monomial_key(order)
if src_order == dst_order:
return self
if not self.is_zero_dimensional:
raise NotImplementedError(
"can't convert Groebner bases of ideals with positive dimension"
)
polys = list(self._basis)
domain = opt.domain
opt = opt.clone(dict(
domain=domain.get_field(),
order=dst_order,
))
from sympy.polys.rings import xring
_ring, _ = xring(opt.gens, opt.domain, src_order)
for i, poly in enumerate(polys):
poly = poly.set_domain(opt.domain).rep.to_dict()
polys[i] = _ring.from_dict(poly)
G = matrix_fglm(polys, _ring, dst_order)
G = [Poly._from_dict(dict(g), opt) for g in G]
if not domain.is_Field:
G = [g.clear_denoms(convert=True)[1] for g in G]
opt.domain = domain
return self._new(G, opt)
def test_dmp_factor_list():
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(0) == (ZZ(0), [])
assert R.dmp_factor_list(7) == (7, [])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(0) == (QQ(0), [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
R, x, y = ring("x,y", ZZ['y'])
assert R.dmp_factor_list(0) == (DMP([], ZZ), [])
assert R.dmp_factor_list(DMP([ZZ(7)], ZZ)) == (DMP([ZZ(7)], ZZ), [])
R, x, y = ring("x,y", QQ['y'])
assert R.dmp_factor_list(0) == (DMP([], QQ), [])
assert R.dmp_factor_list(DMP([QQ(1, 7)], QQ)) == (DMP([QQ(1, 7)], QQ), [])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list_include(0) == [(0, 1)]
assert R.dmp_factor_list_include(7) == [(7, 1)]
R, X = xring("x:200", ZZ)
f, g = X[0]**2 + 2 * X[0] + 1, X[0] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
f, g = X[-1]**2 + 2 * X[-1] + 1, X[-1] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
R, x = ring("x", ZZ)
assert R.dmp_factor_list(x**2 + 2 * x + 1) == (1, [(x + 1, 2)])
R, x = ring("x", QQ)
assert R.dmp_factor_list(QQ(1, 2) * x**2 + x + QQ(1, 2)) == (QQ(1, 2),
[(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(x**2 + 2 * x + 1) == (1, [(x + 1, 2)])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(QQ(1, 2) * x**2 + x + QQ(1, 2)) == (QQ(1, 2),
[(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
f = 4 * x**2 * y + 4 * x * y**2
assert R.dmp_factor_list(f) == \
(4, [(y, 1),
(x, 1),
(x + y, 1)])
assert R.dmp_factor_list_include(f) == \
[(4*y, 1),
(x, 1),
(x + y, 1)]
R, x, y = ring("x,y", QQ)
f = QQ(1, 2) * x**2 * y + QQ(1, 2) * x * y**2
assert R.dmp_factor_list(f) == \
(QQ(1,2), [(y, 1),
(x, 1),
(x + y, 1)])
R, x, y = ring("x,y", RR)
f = 2.0 * x**2 - 8.0 * y**2
assert R.dmp_factor_list(f) == \
(RR(2.0), [(1.0*x - 2.0*y, 1),
(1.0*x + 2.0*y, 1)])
R, x, y = ring("x,y", ZZ['t'])
f = DMP([ZZ(4), ZZ(0)], ZZ) * x**2 + DMP([ZZ(4), ZZ(0), ZZ(0)], ZZ) * x
assert R.dmp_factor_list(f) == \
(DMP([ZZ(4)], ZZ), [(DMP([ZZ(1), ZZ(0)], ZZ), 1),
(DMP([ZZ(1)], ZZ)*x, 1),
(DMP([ZZ(1)], ZZ)*x + DMP([ZZ(1), ZZ(0)], ZZ), 1)])
R, x, y = ring("x,y", QQ['t'])
f = DMP([QQ(1, 2), QQ(0)], QQ) * x**2 + DMP(
[QQ(1, 2), QQ(0), QQ(0)], QQ) * x
assert R.dmp_factor_list(f) == \
(DMP([QQ(1, 2)], QQ), [(DMP([QQ(1), QQ(0)], QQ), 1),
(DMP([QQ(1)], QQ)*x, 1),
(DMP([QQ(1)], QQ)*x + DMP([QQ(1), QQ(0)], QQ), 1)])
R, x, y = ring("x,y", FF(2))
raises(NotImplementedError, lambda: R.dmp_factor_list(x**2 + y**2))
R, x, y = ring("x,y", EX)
raises(DomainError, lambda: R.dmp_factor_list(EX(sin(1))))
def test_dmp_factor_list():
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(0) == (ZZ(0), [])
assert R.dmp_factor_list(7) == (7, [])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(0) == (QQ(0), [])
assert R.dmp_factor_list(QQ(1, 7)) == (QQ(1, 7), [])
R, x, y = ring("x,y", ZZ["y"])
assert R.dmp_factor_list(0) == (DMP([], ZZ), [])
assert R.dmp_factor_list(DMP([ZZ(7)], ZZ)) == (DMP([ZZ(7)], ZZ), [])
R, x, y = ring("x,y", QQ["y"])
assert R.dmp_factor_list(0) == (DMP([], QQ), [])
assert R.dmp_factor_list(DMP([QQ(1, 7)], QQ)) == (DMP([QQ(1, 7)], QQ), [])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list_include(0) == [(0, 1)]
assert R.dmp_factor_list_include(7) == [(7, 1)]
R, X = xring("x:200", ZZ)
f, g = X[0] ** 2 + 2 * X[0] + 1, X[0] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
f, g = X[-1] ** 2 + 2 * X[-1] + 1, X[-1] + 1
assert R.dmp_factor_list(f) == (1, [(g, 2)])
R, x = ring("x", ZZ)
assert R.dmp_factor_list(x ** 2 + 2 * x + 1) == (1, [(x + 1, 2)])
R, x = ring("x", QQ)
assert R.dmp_factor_list(QQ(1, 2) * x ** 2 + x + QQ(1, 2)) == (QQ(1, 2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
assert R.dmp_factor_list(x ** 2 + 2 * x + 1) == (1, [(x + 1, 2)])
R, x, y = ring("x,y", QQ)
assert R.dmp_factor_list(QQ(1, 2) * x ** 2 + x + QQ(1, 2)) == (QQ(1, 2), [(x + 1, 2)])
R, x, y = ring("x,y", ZZ)
f = 4 * x ** 2 * y + 4 * x * y ** 2
assert R.dmp_factor_list(f) == (4, [(y, 1), (x, 1), (x + y, 1)])
assert R.dmp_factor_list_include(f) == [(4 * y, 1), (x, 1), (x + y, 1)]
R, x, y = ring("x,y", QQ)
f = QQ(1, 2) * x ** 2 * y + QQ(1, 2) * x * y ** 2
assert R.dmp_factor_list(f) == (QQ(1, 2), [(y, 1), (x, 1), (x + y, 1)])
R, x, y = ring("x,y", RR)
f = 2.0 * x ** 2 - 8.0 * y ** 2
assert R.dmp_factor_list(f) == (RR(2.0), [(1.0 * x - 2.0 * y, 1), (1.0 * x + 2.0 * y, 1)])
R, x, y = ring("x,y", ZZ["t"])
f = DMP([ZZ(4), ZZ(0)], ZZ) * x ** 2 + DMP([ZZ(4), ZZ(0), ZZ(0)], ZZ) * x
assert R.dmp_factor_list(f) == (
DMP([ZZ(4)], ZZ),
[(DMP([ZZ(1), ZZ(0)], ZZ), 1), (DMP([ZZ(1)], ZZ) * x, 1), (DMP([ZZ(1)], ZZ) * x + DMP([ZZ(1), ZZ(0)], ZZ), 1)],
)
R, x, y = ring("x,y", QQ["t"])
f = DMP([QQ(1, 2), QQ(0)], QQ) * x ** 2 + DMP([QQ(1, 2), QQ(0), QQ(0)], QQ) * x
assert R.dmp_factor_list(f) == (
DMP([QQ(1, 2)], QQ),
[(DMP([QQ(1), QQ(0)], QQ), 1), (DMP([QQ(1)], QQ) * x, 1), (DMP([QQ(1)], QQ) * x + DMP([QQ(1), QQ(0)], QQ), 1)],
)
R, x, y = ring("x,y", FF(2))
raises(NotImplementedError, lambda: R.dmp_factor_list(x ** 2 + y ** 2))
R, x, y = ring("x,y", EX)
raises(DomainError, lambda: R.dmp_factor_list(EX(sin(1))))
def get_new_ring(v_l):
return xring(v_l, GF(65521), grevlex)
