def hyperplane_parameters(poly, vertices=None):
"""A helper function to return the hyperplane parameters
of which the facets of the polytope are a part of.
Parameters
==========
poly :
The input 2/3-Polytope.
vertices :
Vertex indices of 3-Polytope.
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> hyperplane_parameters(cube[1:], cube[0])
[([0, -1, 0], -5), ([0, 0, -1], -5), ([-1, 0, 0], -5),
([0, 1, 0], 0), ([1, 0, 0], 0), ([0, 0, 1], 0)]
"""
if isinstance(poly, Polygon):
vertices = list(poly.vertices) + [poly.vertices[0]
] # Close the polygon
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
else:
params = [None] * len(poly)
for i, polygon in enumerate(poly):
v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
normal = cross_product(v1, v2, v3)
b = sum([normal[j] * v1[j] for j in range(0, 3)])
fac = gcd_list(normal)
if fac.is_zero:
fac = 1
normal = [j / fac for j in normal]
b = b / fac
params[i] = (normal, b)
return params
def hyperplane_parameters(poly, vertices=None):
"""A helper function to return the hyperplane parameters
of which the facets of the polytope are a part of.
Parameters
==========
poly : The input 2/3-Polytope
vertices : Vertex indices of 3-Polytope
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
>>> cube = [[(0, 0, 0), (0, 0, 5), (0, 5, 0), (0, 5, 5), (5, 0, 0),\
(5, 0, 5), (5, 5, 0), (5, 5, 5)],\
[2, 6, 7, 3], [3, 7, 5, 1], [7, 6, 4, 5], [1, 5, 4, 0],\
[3, 1, 0, 2], [0, 4, 6, 2]]
>>> hyperplane_parameters(cube[1:], cube[0])
[([0, -1, 0], -5), ([0, 0, -1], -5), ([-1, 0, 0], -5),
([0, 1, 0], 0), ([1, 0, 0], 0), ([0, 0, 1], 0)]
"""
if isinstance(poly, Polygon):
vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
else:
params = [None] * len(poly)
for i, polygon in enumerate(poly):
v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
normal = cross_product(v1, v2, v3)
b = sum([normal[j] * v1[j] for j in range(0, 3)])
fac = gcd_list(normal)
if fac is S.Zero:
fac = 1
normal = [j / fac for j in normal]
b = b / fac
params[i] = (normal, b)
return params
def hyperplane_parameters(poly, vertices=None):
"""A helper function to return the hyperplane parameters
of which the facets of the polygon are a part of.
Currently works for only 2-Polytopes.
Parameters
==========
poly : The input Polygon
Optional Parameters
----------------------
vertices : Vertex indices of faces of 3-Polytope
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
"""
if isinstance(poly, Polygon):
vertices = list(poly.vertices) + [poly.vertices[0]
] # Close the polygon
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
else:
params = [None] * len(poly)
for i, polygon in enumerate(poly):
v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
normal = cross_product(v1, v2, v3)
b = sum([normal[j] * v1[j] for j in range(0, 3)])
fac = gcd_list(normal)
if fac is S.Zero:
fac = 1
normal = [j / fac for j in normal]
b = b / fac
params[i] = (normal, b)
return params
def hyperplane_parameters(poly, vertices=None):
"""A helper function to return the hyperplane parameters
of which the facets of the polygon are a part of.
Currently works for only 2-Polytopes.
Parameters
==========
poly : The input Polygon
Optional Parameters
----------------------
vertices : Vertex indices of faces of 3-Polytope
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
"""
if isinstance(poly, Polygon):
vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
else:
params = [None] * len(poly)
for i, polygon in enumerate(poly):
v1, v2, v3 = [vertices[vertex] for vertex in polygon[:3]]
normal = cross_product(v1, v2, v3)
b = sum([normal[j] * v1[j] for j in range(0, 3)])
fac = gcd_list(normal)
if fac is S.Zero:
fac = 1
normal = [j / fac for j in normal]
b = b / fac
params[i] = (normal, b)
return params
def _integer_basis(poly):
"""Compute coefficient basis for a polynomial over integers. """
monoms, coeffs = zip(*poly.terms())
monoms, = zip(*monoms)
coeffs = map(abs, coeffs)
if coeffs[0] < coeffs[-1]:
coeffs = list(reversed(coeffs))
else:
return None
monoms = monoms[:-1]
coeffs = coeffs[:-1]
divs = reversed(divisors(gcd_list(coeffs))[1:])
try:
div = divs.next()
except StopIteration:
return None
while True:
for monom, coeff in zip(monoms, coeffs):
if coeff % div**monom != 0:
try:
div = divs.next()
except StopIteration:
return None
else:
break
else:
return div
def _integer_basis(poly):
"""Compute coefficient basis for a polynomial over integers. """
monoms, coeffs = zip(*poly.terms())
monoms, = zip(*monoms)
coeffs = map(abs, coeffs)
if coeffs[0] < coeffs[-1]:
coeffs = list(reversed(coeffs))
else:
return None
monoms = monoms[:-1]
coeffs = coeffs[:-1]
divs = reversed(divisors(gcd_list(coeffs))[1:])
try:
div = divs.next()
except StopIteration:
return None
while True:
for monom, coeff in zip(monoms, coeffs):
if coeff % div**monom != 0:
try:
div = divs.next()
except StopIteration:
return None
else:
break
else:
return div
def hyperplane_parameters(poly):
"""A helper function to return the hyperplane parameters
of which the facets of the polygon are a part of.
Currently works for only 2-Polytopes.
Parameters
==========
poly : The input Polygon
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
"""
vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon.
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b)/factor
a = (S(a1)/factor, S(a2)/factor)
params[i] = (a, b)
return params
def hyperplane_parameters(poly):
"""A helper function to return the hyperplane parameters
of which the facets of the polygon are a part of.
Currently works for only 2-Polytopes.
Parameters
==========
poly : The input Polygon
Examples
========
>>> from sympy.geometry.point import Point
>>> from sympy.geometry.polygon import Polygon
>>> from sympy.integrals.intpoly import hyperplane_parameters
>>> hyperplane_parameters(Polygon(Point(0, 3), Point(5, 3), Point(1, 1)))
[((0, 1), 3), ((1, -2), -1), ((-2, -1), -3)]
"""
vertices = list(poly.vertices) + [poly.vertices[0]] # Close the polygon.
params = [None] * (len(vertices) - 1)
for i in range(len(vertices) - 1):
v1 = vertices[i]
v2 = vertices[i + 1]
a1 = v1[1] - v2[1]
a2 = v2[0] - v1[0]
b = v2[0] * v1[1] - v2[1] * v1[0]
factor = gcd_list([a1, a2, b])
b = S(b) / factor
a = (S(a1) / factor, S(a2) / factor)
params[i] = (a, b)
return params
def _integer_basis(poly):
"""Compute coefficient basis for a polynomial over integers.
Returns the integer ``div`` such that substituting ``x = div*y``
``p(x) = m*q(y)`` where the coefficients of ``q`` are smaller
than those of ``p``.
For example ``x**5 + 512*x + 1024 = 0``
with ``div = 4`` becomes ``y**5 + 2*y + 1 = 0``
Returns the integer ``div`` or ``None`` if there is no possible scaling.
Examples
========
>>> from sympy.polys import Poly
>>> from sympy.abc import x
>>> from sympy.polys.polyroots import _integer_basis
>>> p = Poly(x**5 + 512*x + 1024, x, domain='ZZ')
>>> _integer_basis(p)
4
"""
monoms, coeffs = list(zip(*poly.terms()))
monoms, = list(zip(*monoms))
coeffs = list(map(abs, coeffs))
if coeffs[0] < coeffs[-1]:
coeffs = list(reversed(coeffs))
n = monoms[0]
monoms = [n - i for i in reversed(monoms)]
else:
return None
monoms = monoms[:-1]
coeffs = coeffs[:-1]
divs = reversed(divisors(gcd_list(coeffs))[1:])
try:
div = next(divs)
except StopIteration:
return None
while True:
for monom, coeff in zip(monoms, coeffs):
if coeff % div**monom != 0:
try:
div = next(divs)
except StopIteration:
return None
else:
break
else:
return div
