def dup_gff_list(f, K):
"""
Compute greatest factorial factorization of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_gff_list(x**5 + 2*x**4 - x**3 - 2*x**2)
[(x, 1), (x + 2, 4)]
"""
if not f:
raise ValueError("greatest factorial factorization doesn't exist for a zero polynomial")
f = dup_monic(f, K)
if not dup_degree(f):
return []
else:
g = dup_gcd(f, dup_shift(f, K.one, K), K)
H = dup_gff_list(g, K)
for i, (h, k) in enumerate(H):
g = dup_mul(g, dup_shift(h, -K(k), K), K)
H[i] = (h, k + 1)
f = dup_quo(f, g, K)
if not dup_degree(f):
return H
else:
return [(f, 1)] + H
def dup_gff_list(f, K):
"""
Compute greatest factorial factorization of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys import ring, ZZ
>>> R, x = ring("x", ZZ)
>>> R.dup_gff_list(x**5 + 2*x**4 - x**3 - 2*x**2)
[(x, 1), (x + 2, 4)]
"""
if not f:
raise ValueError("greatest factorial factorization doesn't exist for a zero polynomial")
f = dup_monic(f, K)
if not dup_degree(f):
return []
else:
g = dup_gcd(f, dup_shift(f, K.one, K), K)
H = dup_gff_list(g, K)
for i, (h, k) in enumerate(H):
g = dup_mul(g, dup_shift(h, -K(k), K), K)
H[i] = (h, k + 1)
f = dup_quo(f, g, K)
if not dup_degree(f):
return H
else:
return [(f, 1)] + H
def dup_ext_factor(f, K):
"""Factor univariate polynomials over algebraic number fields. """
n, lc = dup_degree(f), dup_LC(f, K)
f = dup_monic(f, K)
if n <= 0:
return lc, []
if n == 1:
return lc, [(f, 1)]
f, F = dup_sqf_part(f, K), f
s, g, r = dup_sqf_norm(f, K)
factors = dup_factor_list_include(r, K.dom)
if len(factors) == 1:
return lc, [(f, n // dup_degree(f))]
H = s * K.unit
for i, (factor, _) in enumerate(factors):
h = dup_convert(factor, K.dom, K)
h, _, g = dup_inner_gcd(h, g, K)
h = dup_shift(h, H, K)
factors[i] = h
factors = dup_trial_division(F, factors, K)
return lc, factors
def dup_ext_factor(f, K):
"""Factor univariate polynomials over algebraic number fields. """
n, lc = dup_degree(f), dup_LC(f, K)
f = dup_monic(f, K)
if n <= 0:
return lc, []
if n == 1:
return lc, [(f, 1)]
f, F = dup_sqf_part(f, K), f
s, g, r = dup_sqf_norm(f, K)
factors = dup_factor_list_include(r, K.dom)
if len(factors) == 1:
return lc, [(f, n//dup_degree(f))]
H = s*K.unit
for i, (factor, _) in enumerate(factors):
h = dup_convert(factor, K.dom, K)
h, _, g = dup_inner_gcd(h, g, K)
h = dup_shift(h, H, K)
factors[i] = h
factors = dup_trial_division(F, factors, K)
return lc, factors
def dup_gff_list(f, K):
"""
Compute greatest factorial factorization of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.sqfreetools import dup_gff_list
>>> f = ZZ.map([1, 2, -1, -2, 0, 0])
>>> dup_gff_list(f, ZZ)
[([1, 0], 1), ([1, 2], 4)]
"""
if not f:
raise ValueError(
"greatest factorial factorization doesn't exist for a zero polynomial"
)
f = dup_monic(f, K)
if not dup_degree(f):
return []
else:
g = dup_gcd(f, dup_shift(f, K.one, K), K)
H = dup_gff_list(g, K)
for i, (h, k) in enumerate(H):
g = dup_mul(g, dup_shift(h, -K(k), K), K)
H[i] = (h, k + 1)
f = dup_quo(f, g, K)
if not dup_degree(f):
return H
else:
return [(f, 1)] + H
def dup_gff_list(f, K):
"""
Compute greatest factorial factorization of ``f`` in ``K[x]``.
Examples
========
>>> from sympy.polys.domains import ZZ
>>> from sympy.polys.sqfreetools import dup_gff_list
>>> f = ZZ.map([1, 2, -1, -2, 0, 0])
>>> dup_gff_list(f, ZZ)
[([1, 0], 1), ([1, 2], 4)]
"""
if not f:
raise ValueError("greatest factorial factorization doesn't exist for a zero polynomial")
f = dup_monic(f, K)
if not dup_degree(f):
return []
else:
g = dup_gcd(f, dup_shift(f, K.one, K), K)
H = dup_gff_list(g, K)
for i, (h, k) in enumerate(H):
g = dup_mul(g, dup_shift(h, -K(k), K), K)
H[i] = (h, k + 1)
f = dup_quo(f, g, K)
if not dup_degree(f):
return H
else:
return [(f, 1)] + H
def dup_sqf_norm(f, K):
"""
Square-free norm of ``f`` in ``K[x]``, useful over algebraic domains.
Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and ``r(x) = Norm(g(x))``
is a square-free polynomial over K, where ``a`` is the algebraic extension of ``K``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> from sympy import sqrt
>>> K = QQ.algebraic_field(sqrt(3))
>>> R, x = ring("x", K)
>>> _, X = ring("x", QQ)
>>> s, f, r = R.dup_sqf_norm(x**2 - 2)
>>> s == 1
True
>>> f == x**2 + K([QQ(-2), QQ(0)])*x + 1
True
>>> r == X**4 - 10*X**2 + 1
True
"""
if not K.is_Algebraic:
raise DomainError("ground domain must be algebraic")
s, g = 0, dmp_raise(K.mod.rep, 1, 0, K.dom)
while True:
h, _ = dmp_inject(f, 0, K, front=True)
r = dmp_resultant(g, h, 1, K.dom)
if dup_sqf_p(r, K.dom):
break
else:
f, s = dup_shift(f, -K.unit, K), s + 1
return s, f, r
def dup_sqf_norm(f, K):
"""
Square-free norm of ``f`` in ``K[x]``, useful over algebraic domains.
Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and ``r(x) = Norm(g(x))``
is a square-free polynomial over K, where ``a`` is the algebraic extension of ``K``.
Examples
========
>>> from sympy.polys import ring, QQ
>>> from sympy import sqrt
>>> K = QQ.algebraic_field(sqrt(3))
>>> R, x = ring("x", K)
>>> _, X = ring("x", QQ)
>>> s, f, r = R.dup_sqf_norm(x**2 - 2)
>>> s == 1
True
>>> f == x**2 + K([QQ(-2), QQ(0)])*x + 1
True
>>> r == X**4 - 10*X**2 + 1
True
"""
if not K.is_Algebraic:
raise DomainError("ground domain must be algebraic")
s, g = 0, dmp_raise(K.mod.rep, 1, 0, K.dom)
while True:
h, _ = dmp_inject(f, 0, K, front=True)
r = dmp_resultant(g, h, 1, K.dom)
if dup_sqf_p(r, K.dom):
break
else:
f, s = dup_shift(f, -K.unit, K), s + 1
return s, f, r
def dup_sqf_norm(f, K):
"""
Square-free norm of ``f`` in ``K[x]``, useful over algebraic domains.
Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and ``r(x) = Norm(g(x))``
is a square-free polynomial over K, where ``a`` is the algebraic extension of ``K``.
**Examples**
>>> from sympy import sqrt
>>> from sympy.polys.domains import QQ
>>> from sympy.polys.sqfreetools import dup_sqf_norm
>>> K = QQ.algebraic_field(sqrt(3))
>>> s, f, r = dup_sqf_norm([K(1), K(0), K(-2)], K)
>>> s == 1
True
>>> f == [K(1), K([QQ(-2), QQ(0)]), K(1)]
True
>>> r == [1, 0, -10, 0, 1]
True
"""
if not K.is_Algebraic:
raise DomainError("ground domain must be algebraic")
s, g = 0, dmp_raise(K.mod.rep, 1, 0, K.dom)
while True:
h, _ = dmp_inject(f, 0, K, front=True)
r = dmp_resultant(g, h, 1, K.dom)
if dup_sqf_p(r, K.dom):
break
else:
f, s = dup_shift(f, -K.unit, K), s+1
return s, f, r
def test_dup_shift():
assert dup_shift([], 1, ZZ) == []
assert dup_shift([1], 1, ZZ) == [1]
assert dup_shift([1, 2, 3, 4, 5], 1, ZZ) == [1, 6, 15, 20, 15]
assert dup_shift([1, 2, 3, 4, 5], 7, ZZ) == [1, 30, 339, 1712, 3267]
def shift(f, a):
"""Efficiently compute Taylor shift ``f(x + a)``. """
if not f.lev:
return f.per(dup_shift(f.rep, f.dom.convert(a), f.dom))
else:
raise ValueError('univariate polynomial expected')
def test_dup_shift():
assert dup_shift([], 1, ZZ) == []
assert dup_shift([1], 1, ZZ) == [1]
assert dup_shift([1, 2, 3, 4, 5], 1, ZZ) == [1, 6, 15, 20, 15]
assert dup_shift([1, 2, 3, 4, 5], 7, ZZ) == [1, 30, 339, 1712, 3267]
def shift(f, a):
"""Efficiently compute Taylor shift ``f(x + a)``. """
if not f.lev:
return f.per(dup_shift(f.rep, f.dom.convert(a), f.dom))
else:
raise ValueError('univariate polynomial expected')
