def swinnerton_dyer_poly(n, x=None, **args):
"""Generates n-th Swinnerton-Dyer polynomial in `x`. """
from .numberfields import minimal_polynomial
if n <= 0:
raise ValueError(
"can't generate Swinnerton-Dyer polynomial of order %s" % n)
if x is not None:
sympify(x)
else:
x = Dummy('x')
if n > 3:
p = 2
a = [sqrt(2)]
for i in range(2, n + 1):
p = nextprime(p)
a.append(sqrt(p))
return minimal_polynomial(Add(*a), x, polys=args.get('polys', False))
if n == 1:
ex = x**2 - 2
elif n == 2:
ex = x**4 - 10 * x**2 + 1
elif n == 3:
ex = x**8 - 40 * x**6 + 352 * x**4 - 960 * x**2 + 576
if not args.get('polys', False):
return ex
else:
return PurePoly(ex, x)
def test_sympyissue_3449():
# test if powers are simplified correctly
# see also issue sympy/sympy#3995
x = Symbol('x')
assert ((x**Rational(1, 3))**Rational(2)) == x**Rational(2, 3)
assert (
(x**Rational(3))**Rational(2, 5)) == (x**Rational(3))**Rational(2, 5)
a = Symbol('a', extended_real=True)
b = Symbol('b', extended_real=True)
assert (a**2)**b == (abs(a)**b)**2
assert sqrt(1/a) != 1/sqrt(a) # e.g. for a = -1
assert (a**3)**Rational(1, 3) != a
assert (x**a)**b != x**(a*b) # e.g. x = -1, a=2, b=1/2
assert (x**.5)**b == x**(.5*b)
assert (x**.5)**.5 == x**.25
assert (x**2.5)**.5 != x**1.25 # e.g. for x = 5*I
k = Symbol('k', integer=True)
m = Symbol('m', integer=True)
assert (x**k)**m == x**(k*m)
assert Number(5)**Rational(2, 3) == Number(25)**Rational(1, 3)
assert (x**.5)**2 == x**1.0
assert (x**2)**k == (x**k)**2 == x**(2*k)
a = Symbol('a', positive=True)
assert (a**3)**Rational(2, 5) == a**Rational(6, 5)
assert (a**2)**b == (a**b)**2
assert (a**Rational(2, 3))**x == (a**(2*x/3)) != (a**x)**Rational(2, 3)
def test_sympyissue_3449():
# test if powers are simplified correctly
# see also issue sympy/sympy#3995
assert cbrt(x)**2 == x**Rational(2, 3)
assert (x**3)**Rational(2, 5) == Pow(x**3, Rational(2, 5), evaluate=False)
a = Symbol('a', extended_real=True)
b = Symbol('b', extended_real=True)
assert (a**2)**b == (abs(a)**b)**2
assert sqrt(1/a) != 1/sqrt(a) # e.g. for a = -1
assert cbrt(a**3) != a
assert (x**a)**b != x**(a*b) # e.g. x = -1, a=2, b=1/2
assert (x**.5)**b == x**(.5*b)
assert (x**.5)**.5 == x**.25
assert (x**2.5)**.5 != x**1.25 # e.g. for x = 5*I
k = Symbol('k', integer=True)
m = Symbol('m', integer=True)
assert (x**k)**m == x**(k*m)
assert Number(5)**Rational(2, 3) == cbrt(Number(25))
assert (x**.5)**2 == x**1.0
assert (x**2)**k == (x**k)**2 == x**(2*k)
a = Symbol('a', positive=True)
assert (a**3)**Rational(2, 5) == a**Rational(6, 5)
assert (a**2)**b == (a**b)**2
assert (a**Rational(2, 3))**x == (a**(2*x/3)) != (a**x)**Rational(2, 3)
def test_sympyissue_6990():
x = Symbol('x')
a = Symbol('a')
b = Symbol('b')
assert (sqrt(a + b*x + x**2)).series(x, 0, 3).removeO() == \
b*x/(2*sqrt(a)) + x**2*(1/(2*sqrt(a)) -
b**2/(8*a**Rational(3, 2))) + sqrt(a)
def test_root():
from diofant.abc import x
n = Symbol('n', integer=True)
k = Symbol('k', integer=True)
assert root(2, 2) == sqrt(2)
assert root(2, 1) == 2
assert root(2, 3) == 2**Rational(1, 3)
assert root(2, 3) == cbrt(2)
assert root(2, -5) == 2**Rational(4, 5) / 2
assert root(-2, 1) == -2
assert root(-2, 2) == sqrt(2) * I
assert root(-2, 1) == -2
assert root(x, 2) == sqrt(x)
assert root(x, 1) == x
assert root(x, 3) == x**Rational(1, 3)
assert root(x, 3) == cbrt(x)
assert root(x, -5) == x**Rational(-1, 5)
assert root(x, n) == x**(1 / n)
assert root(x, -n) == x**(-1 / n)
assert root(x, n, k) == x**(1 / n) * (-1)**(2 * k / n)
def eval(cls, arg):
if arg.is_Number:
if arg is S.Infinity:
return S.Infinity
elif arg.is_Integer:
if arg.is_positive:
return factorial(arg - 1)
else:
return S.ComplexInfinity
elif arg.is_Rational:
if arg.q == 2:
n = abs(arg.p) // arg.q
if arg.is_positive:
k, coeff = n, S.One
else:
n = k = n + 1
if n & 1 == 0:
coeff = S.One
else:
coeff = S.NegativeOne
for i in range(3, 2 * k, 2):
coeff *= i
if arg.is_positive:
return coeff * sqrt(S.Pi) / 2**n
else:
return 2**n * sqrt(S.Pi) / coeff
if arg.is_integer and arg.is_nonpositive:
return S.ComplexInfinity
def as_real_imag(self, deep=True, **hints):
# TODO: Handle deep and hints
n, m, theta, phi = self.args
re = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
cos(m*phi) * assoc_legendre(n, m, cos(theta)))
im = (sqrt((2*n + 1)/(4*pi) * factorial(n - m)/factorial(n + m)) *
sin(m*phi) * assoc_legendre(n, m, cos(theta)))
return re, im
def as_real_imag(self, deep=True, **hints):
x, y = self._as_real_imag(deep=deep, **hints)
sq = -y**2 / x**2
re = S.Half * (self.func(x + x * sqrt(sq)) +
self.func(x - x * sqrt(sq)))
im = x / (2 * y) * sqrt(sq) * (self.func(x - x * sqrt(sq)) -
self.func(x + x * sqrt(sq)))
return re, im
def eval(cls, n, m, theta, phi):
n, m, th, ph = [sympify(x) for x in (n, m, theta, phi)]
if m.is_positive:
zz = (Ynm(n, m, th, ph) + Ynm_c(n, m, th, ph)) / sqrt(2)
return zz
elif m.is_zero:
return Ynm(n, m, th, ph)
elif m.is_negative:
zz = (Ynm(n, m, th, ph) - Ynm_c(n, m, th, ph)) / (sqrt(2)*I)
return zz
def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = tt * Pow(z, Rational(3, 2))
if re(z).is_positive:
return z / sqrt(3) * (besseli(-tt, a) + besseli(tt, a))
else:
a = Pow(z, Rational(3, 2))
b = Pow(a, tt)
c = Pow(a, -tt)
return sqrt(ot) * (b * besseli(-tt, tt * a) +
z**2 * c * besseli(tt, tt * a))
def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(z, Rational(3, 2))
if re(z).is_positive:
return sqrt(z) / sqrt(3) * (besseli(-ot, tt * a) +
besseli(ot, tt * a))
else:
b = Pow(a, ot)
c = Pow(a, -ot)
return sqrt(ot) * (b * besseli(-ot, tt * a) +
z * c * besseli(ot, tt * a))
def test_rational():
a = Rational(1, 5)
r = sqrt(5)/5
assert sqrt(a) == r
assert 2*sqrt(a) == 2*r
r = a*a**Rational(1, 2)
assert a**Rational(3, 2) == r
assert 2*a**Rational(3, 2) == 2*r
r = a**5*a**Rational(2, 3)
assert a**Rational(17, 3) == r
assert 2 * a**Rational(17, 3) == 2*r
def test_rational():
a = Rational(1, 5)
r = sqrt(5)/5
assert sqrt(a) == r
assert 2*sqrt(a) == 2*r
r = a*sqrt(a)
assert a**Rational(3, 2) == r
assert 2*a**Rational(3, 2) == 2*r
r = a**5*a**Rational(2, 3)
assert a**Rational(17, 3) == r
assert 2 * a**Rational(17, 3) == 2*r
def test_sympyissue_6208():
assert sqrt(33**(9*I/10)) == -33**(9*I/20)
assert root((6*I)**(2*I), 3).as_base_exp()[1] == Rational(1, 3) # != 2*I/3
assert root((6*I)**(I/3), 3).as_base_exp()[1] == I/9
assert sqrt(exp(3*I)) == exp(3*I/2)
assert sqrt(-sqrt(3)*(1 + 2*I)) == sqrt(sqrt(3))*sqrt(-1 - 2*I)
assert sqrt(exp(5*I)) == -exp(5*I/2)
assert root(exp(5*I), 3).exp == Rational(1, 3)
def test_sympyissue_6208():
assert sqrt(33**(9*I/10)) == -33**(9*I/20)
assert root((6*I)**(2*I), 3).as_base_exp()[1] == Rational(1, 3) # != 2*I/3
assert root((6*I)**(I/3), 3).as_base_exp()[1] == I/9
assert sqrt(exp(3*I)) == exp(3*I/2)
assert sqrt(-sqrt(3)*(1 + 2*I)) == sqrt(sqrt(3))*sqrt(-1 - 2*I)
assert sqrt(exp(5*I)) == -exp(5*I/2)
assert root(exp(5*I), 3).exp == Rational(1, 3)
def _eval_expand_func(self, **hints):
arg = self.args[0]
symbs = arg.free_symbols
if len(symbs) == 1:
z = symbs.pop()
c = Wild("c", exclude=[z])
d = Wild("d", exclude=[z])
m = Wild("m", exclude=[z])
n = Wild("n", exclude=[z])
M = arg.match(c * (d * z**n)**m)
if M is not None:
m = M[m]
# The transformation is in principle
# given by 03.08.16.0001.01 but note
# that there is an error in this formule.
# http://functions.wolfram.com/Bessel-TypeFunctions/AiryBiPrime/16/01/01/0001/
if (3 * m).is_integer:
c = M[c]
d = M[d]
n = M[n]
pf = (d**m * z**(n * m)) / (d * z**n)**m
newarg = c * d**m * z**(n * m)
return S.Half * (sqrt(3) *
(pf - S.One) * airyaiprime(newarg) +
(pf + S.One) * airybiprime(newarg))
def _cholesky_sparse(self):
"""Algorithm for numeric Cholesky factorization of a sparse matrix."""
Crowstruc = self.row_structure_symbolic_cholesky()
C = self.zeros(self.rows)
for i in range(len(Crowstruc)):
for j in Crowstruc[i]:
if i != j:
C[i, j] = self[i, j]
summ = 0
for p1 in Crowstruc[i]:
if p1 < j:
for p2 in Crowstruc[j]:
if p2 < j:
if p1 == p2:
summ += C[i, p1] * C[j, p1]
else:
break
else:
break
C[i, j] -= summ
C[i, j] /= C[j, j]
else:
C[j, j] = self[j, j]
summ = 0
for k in Crowstruc[j]:
if k < j:
summ += C[j, k]**2
else:
break
C[j, j] -= summ
C[j, j] = sqrt(C[j, j])
return C
def fdiff(self, argindex=1):
if len(self.args) == 3:
n, z, m = self.args
fm, fn = sqrt(1 - m * sin(z)**2), 1 - n * sin(z)**2
if argindex == 1:
return (elliptic_e(z, m) + (m - n) * elliptic_f(z, m) / n +
(n**2 - m) * elliptic_pi(n, z, m) / n -
n * fm * sin(2 * z) / (2 * fn)) / (2 * (m - n) *
(n - 1))
elif argindex == 2:
return 1 / (fm * fn)
elif argindex == 3:
return (elliptic_e(z, m) /
(m - 1) + elliptic_pi(n, z, m) - m * sin(2 * z) /
(2 * (m - 1) * fm)) / (2 * (n - m))
else:
n, m = self.args
if argindex == 1:
return (elliptic_e(m) + (m - n) * elliptic_k(m) / n +
(n**2 - m) * elliptic_pi(n, m) / n) / (2 * (m - n) *
(n - 1))
elif argindex == 2:
return (elliptic_e(m) /
(m - 1) + elliptic_pi(n, m)) / (2 * (n - m))
raise ArgumentIndexError(self, argindex)
def distance(self, p):
"""The Euclidean distance from self to point p.
Parameters
==========
p : Point
Returns
=======
distance : number or symbolic expression.
See Also
========
diofant.geometry.line.Segment.length
Examples
========
>>> from diofant.geometry import Point
>>> p1, p2 = Point(1, 1), Point(4, 5)
>>> p1.distance(p2)
5
>>> from diofant.abc import x, y
>>> p3 = Point(x, y)
>>> p3.distance(Point(0, 0))
sqrt(x**2 + y**2)
"""
p = Point(p)
return sqrt(sum((a - b)**2 for a, b in zip(self.args, p.args)))
def direction_cosine(self, point):
"""
Gives the direction cosine between 2 points
Parameters
==========
p : Point3D
Returns
=======
list
Examples
========
>>> from diofant import Point3D
>>> p1 = Point3D(1, 2, 3)
>>> p1.direction_cosine(Point3D(2, 3, 5))
[sqrt(6)/6, sqrt(6)/6, sqrt(6)/3]
"""
a = self.direction_ratio(point)
b = sqrt(sum(i**2 for i in a))
return [(point.x - self.x) / b, (point.y - self.y) / b,
(point.z - self.z) / b]
def _eval_rewrite_as_besseli(self, z):
ot = Rational(1, 3)
tt = Rational(2, 3)
a = Pow(z, Rational(3, 2))
if re(z).is_positive:
return ot * sqrt(z) * (besseli(-ot, tt * a) - besseli(ot, tt * a))
else:
return ot * (Pow(a, ot) * besseli(-ot, tt * a) -
z * Pow(a, -ot) * besseli(ot, tt * a))
def test_valued_tensor_pow():
(A, B, AB, BA, C, Lorentz, E, px, py, pz, LorentzD, mu0, mu1, mu2, ndm, n0,
n1, n2, NA, NB, NC, minkowski, ba_matrix, ndm_matrix, i0, i1, i2, i3,
i4) = _get_valued_base_test_variables()
assert C**2 == -E**2 + px**2 + py**2 + pz**2
assert C**1 == sqrt(-E**2 + px**2 + py**2 + pz**2)
assert C(mu0)**2 == C**2
assert C(mu0)**1 == C**1
def fdiff(self, argindex=1):
z, m = self.args
fm = sqrt(1 - m * sin(z)**2)
if argindex == 1:
return 1 / fm
elif argindex == 2:
return (elliptic_e(z, m) / (2 * m * (1 - m)) - elliptic_f(z, m) /
(2 * m) - sin(2 * z) / (4 * (1 - m) * fm))
raise ArgumentIndexError(self, argindex)
def test_issue_6208():
from diofant import root, Rational
I = S.ImaginaryUnit
assert sqrt(33**(9 * I / 10)) == -33**(9 * I / 20)
assert root((6 * I)**(2 * I),
3).as_base_exp()[1] == Rational(1, 3) # != 2*I/3
assert root((6 * I)**(I / 3), 3).as_base_exp()[1] == I / 9
assert sqrt(exp(3 * I)) == exp(3 * I / 2)
assert sqrt(-sqrt(3) * (1 + 2 * I)) == sqrt(sqrt(3)) * sqrt(-1 - 2 * I)
assert sqrt(exp(5 * I)) == -exp(5 * I / 2)
assert root(exp(5 * I), 3).exp == Rational(1, 3)
def jacobi_normalized(n, a, b, x):
r"""
Jacobi polynomial :math:`P_n^{\left(\alpha, \beta\right)}(x)`
jacobi_normalized(n, alpha, beta, x) gives the nth Jacobi polynomial
in x, :math:`P_n^{\left(\alpha, \beta\right)}(x)`.
The Jacobi polynomials are orthogonal on :math:`[-1, 1]` with respect
to the weight :math:`\left(1-x\right)^\alpha \left(1+x\right)^\beta`.
This functions returns the polynomials normilzed:
.. math::
\int_{-1}^{1}
P_m^{\left(\alpha, \beta\right)}(x)
P_n^{\left(\alpha, \beta\right)}(x)
(1-x)^{\alpha} (1+x)^{\beta} \mathrm{d}x
= \delta_{m,n}
Examples
========
>>> from diofant import jacobi_normalized
>>> from diofant.abc import n,a,b,x
>>> jacobi_normalized(n, a, b, x)
jacobi(n, a, b, x)/sqrt(2**(a + b + 1)*gamma(a + n + 1)*gamma(b + n + 1)/((a + b + 2*n + 1)*factorial(n)*gamma(a + b + n + 1)))
See Also
========
gegenbauer,
chebyshevt_root, chebyshevu, chebyshevu_root,
legendre, assoc_legendre,
hermite,
laguerre, assoc_laguerre,
diofant.polys.orthopolys.jacobi_poly,
diofant.polys.orthopolys.gegenbauer_poly
diofant.polys.orthopolys.chebyshevt_poly
diofant.polys.orthopolys.chebyshevu_poly
diofant.polys.orthopolys.hermite_poly
diofant.polys.orthopolys.legendre_poly
diofant.polys.orthopolys.laguerre_poly
References
==========
.. [1] http://en.wikipedia.org/wiki/Jacobi_polynomials
.. [2] http://mathworld.wolfram.com/JacobiPolynomial.html
.. [3] http://functions.wolfram.com/Polynomials/JacobiP/
"""
nfactor = (Integer(2)**(a + b + 1) * (gamma(n + a + 1) * gamma(n + b + 1))
/ (2*n + a + b + 1) / (factorial(n) * gamma(n + a + b + 1)))
return jacobi(n, a, b, x) / sqrt(nfactor)
def eval(cls, a, x):
# For lack of a better place, we use this one to extract branching
# information. The following can be
# found in the literature (c/f references given above), albeit scattered:
# 1) For fixed x != 0, lowergamma(s, x) is an entire function of s
# 2) For fixed positive integers s, lowergamma(s, x) is an entire
# function of x.
# 3) For fixed non-positive integers s,
# lowergamma(s, exp(I*2*pi*n)*x) =
# 2*pi*I*n*(-1)**(-s)/factorial(-s) + lowergamma(s, x)
# (this follows from lowergamma(s, x).diff(x) = x**(s-1)*exp(-x)).
# 4) For fixed non-integral s,
# lowergamma(s, x) = x**s*gamma(s)*lowergamma_unbranched(s, x),
# where lowergamma_unbranched(s, x) is an entire function (in fact
# of both s and x), i.e.
# lowergamma(s, exp(2*I*pi*n)*x) = exp(2*pi*I*n*a)*lowergamma(a, x)
from diofant import unpolarify, I
nx, n = x.extract_branch_factor()
if a.is_integer and a.is_positive:
nx = unpolarify(x)
if nx != x:
return lowergamma(a, nx)
elif a.is_integer and a.is_nonpositive:
if n != 0:
return 2 * pi * I * n * (-1)**(
-a) / factorial(-a) + lowergamma(a, nx)
elif n != 0:
return exp(2 * pi * I * n * a) * lowergamma(a, nx)
# Special values.
if a.is_Number:
# TODO this should be non-recursive
if a is S.One:
return S.One - exp(-x)
elif a is S.Half:
return sqrt(pi) * erf(sqrt(x))
elif a.is_Integer or (2 * a).is_Integer:
b = a - 1
if b.is_positive:
return b * cls(b, x) - x**b * exp(-x)
if not a.is_Integer:
return (cls(a + 1, x) + x**a * exp(-x)) / a
def _cholesky(self):
"""Helper function of cholesky.
Without the error checks.
To be used privately. """
L = zeros(self.rows, self.rows)
for i in range(self.rows):
for j in range(i):
L[i, j] = (1 / L[j, j]) * (self[i, j] - sum(L[i, k] * L[j, k]
for k in range(j)))
L[i, i] = sqrt(self[i, i] - sum(L[i, k]**2 for k in range(i)))
return self._new(L)
def fdiff(self, argindex=1):
if len(self.args) == 2:
z, m = self.args
if argindex == 1:
return sqrt(1 - m * sin(z)**2)
elif argindex == 2:
return (elliptic_e(z, m) - elliptic_f(z, m)) / (2 * m)
else:
z = self.args[0]
if argindex == 1:
return (elliptic_e(z) - elliptic_k(z)) / (2 * z)
raise ArgumentIndexError(self, argindex)
def test_real_root():
assert real_root(-8, 3) == -2
assert real_root(-16, 4) == root(-16, 4)
r = root(-7, 4)
assert real_root(r) == r
r1 = root(-1, 3)
r2 = r1**2
r3 = root(-1, 4)
assert real_root(r1 + r2 + r3) == -1 + r2 + r3
assert real_root(root(-2, 3)) == -root(2, 3)
assert real_root(-8., 3) == -2
x = Symbol('x')
n = Symbol('n')
g = real_root(x, n)
assert g.subs(dict(x=-8, n=3)) == -2
assert g.subs(dict(x=8, n=3)) == 2
# give principle root if there is no real root -- if this is not desired
# then maybe a Root class is needed to raise an error instead
assert g.subs(dict(x=I, n=3)) == cbrt(I)
assert g.subs(dict(x=-8, n=2)) == sqrt(-8)
assert g.subs(dict(x=I, n=2)) == sqrt(I)
def eval(cls, z):
if z is S.Zero:
return pi / 2
elif z is S.Half:
return 8 * pi**Rational(3, 2) / gamma(-Rational(1, 4))**2
elif z is S.One:
return S.ComplexInfinity
elif z is S.NegativeOne:
return gamma(Rational(1, 4))**2 / (4 * sqrt(2 * pi))
elif z in (S.Infinity, S.NegativeInfinity, I * S.Infinity,
I * S.NegativeInfinity, S.ComplexInfinity):
return S.Zero
def fdiff(self, argindex=4):
if argindex == 3:
# Diff wrt theta
n, m, theta, phi = self.args
return (m * cot(theta) * Ynm(n, m, theta, phi) +
sqrt((n - m)*(n + m + 1)) * exp(-I*phi) * Ynm(n, m + 1, theta, phi))
elif argindex == 4:
# Diff wrt phi
n, m, theta, phi = self.args
return I * m * Ynm(n, m, theta, phi)
else: # diff wrt n, m, etc
raise ArgumentIndexError(self, argindex)
def eval(cls, a, z):
from diofant import unpolarify, I, expint
if z.is_Number:
if z is S.Infinity:
return S.Zero
elif z is S.Zero:
# TODO: Holds only for Re(a) > 0:
return gamma(a)
# We extract branching information here. C/f lowergamma.
nx, n = z.extract_branch_factor()
if a.is_integer and (a > 0) is S.true:
nx = unpolarify(z)
if z != nx:
return uppergamma(a, nx)
elif a.is_integer and (a <= 0) is S.true:
if n != 0:
return -2 * pi * I * n * (-1)**(
-a) / factorial(-a) + uppergamma(a, nx)
elif n != 0:
return gamma(a) * (1 - exp(2 * pi * I * n * a)) + exp(
2 * pi * I * n * a) * uppergamma(a, nx)
# Special values.
if a.is_Number:
# TODO this should be non-recursive
if a is S.One:
return exp(-z)
elif a is S.Half:
return sqrt(pi) * (1 - erf(sqrt(z))) # TODO could use erfc...
elif a.is_Integer or (2 * a).is_Integer:
b = a - 1
if b.is_positive:
return b * cls(b, z) + z**b * exp(-z)
elif b.is_Integer:
return expint(-b, z) * unpolarify(z)**(b + 1)
if not a.is_Integer:
return (cls(a + 1, z) - z**a * exp(-z)) / a
def eval(cls, n, m, z=None):
if z is not None:
n, z, m = n, m, z
k = 2 * z / pi
if n == S.Zero:
return elliptic_f(z, m)
elif n == S.One:
return (elliptic_f(z, m) +
(sqrt(1 - m * sin(z)**2) * tan(z) - elliptic_e(z, m)) /
(1 - m))
elif k.is_integer:
return k * elliptic_pi(n, m)
elif m == S.Zero:
return atanh(sqrt(n - 1) * tan(z)) / sqrt(n - 1)
elif n == m:
return (elliptic_f(z, n) - elliptic_pi(1, z, n) +
tan(z) / sqrt(1 - n * sin(z)**2))
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif z.could_extract_minus_sign():
return -elliptic_pi(n, -z, m)
else:
if n == S.Zero:
return elliptic_k(m)
elif n == S.One:
return S.ComplexInfinity
elif m == S.Zero:
return pi / (2 * sqrt(1 - n))
elif m == S.One:
return -S.Infinity / sign(n - 1)
elif n == m:
return elliptic_e(n) / (1 - n)
elif n in (S.Infinity, S.NegativeInfinity):
return S.Zero
elif m in (S.Infinity, S.NegativeInfinity):
return S.Zero
def test_sympyissue_6068():
assert sqrt(sin(x)).series(x, 0, 8) == \
sqrt(x) - x**Rational(5, 2)/12 + x**Rational(9, 2)/1440 - \
x**Rational(13, 2)/24192 + O(x**8)
assert sqrt(sin(x)).series(x, 0, 10) == \
sqrt(x) - x**Rational(5, 2)/12 + x**Rational(9, 2)/1440 - \
x**Rational(13, 2)/24192 - 67*x**Rational(17, 2)/29030400 + O(x**10)
assert sqrt(sin(x**3)).series(x, 0, 19) == \
x**Rational(3, 2) - x**Rational(15, 2)/12 + x**Rational(27, 2)/1440 + O(x**19)
assert sqrt(sin(x**3)).series(x, 0, 20) == \
x**Rational(3, 2) - x**Rational(15, 2)/12 + x**Rational(27, 2)/1440 - \
x**Rational(39, 2)/24192 + O(x**20)
def test_sympyissue_3866():
assert --sqrt(sqrt(5) - 1) == sqrt(sqrt(5) - 1)
def test_sympyissue_6990():
assert (sqrt(a + b*x + x**2)).series(x, 0, 3).removeO() == \
b*x/(2*sqrt(a)) + x**2*(1/(2*sqrt(a)) -
b**2/(8*a**Rational(3, 2))) + sqrt(a)
def test_sympyissue_6782():
assert sqrt(sin(x**3)).series(x, 0, 7) == x**Rational(3, 2) + O(x**7)
assert sqrt(sin(x**4)).series(x, 0, 3) == x**2 + O(x**3)
def test_sympyissue_7638():
f = pi/log(sqrt(2))
assert ((1 + I)**(I*f/2))**0.3 == (1 + I)**(0.15*I*f)
# if 1/3 -> 1.0/3 this should fail since it cannot be shown that the
# sign will be +/-1; for the previous "small arg" case, it didn't matter
# that this could not be proved
assert (1 + I)**(4*I*f) == cbrt((1 + I)**(12*I*f))
assert cbrt((1 + I)**(I*(1 + 7*f))).exp == Rational(1, 3)
r = symbols('r', extended_real=True)
assert sqrt(r**2) == abs(r)
assert cbrt(r**3) != r
assert sqrt(Pow(2*I, Rational(5, 2))) != (2*I)**Rational(5, 4)
p = symbols('p', positive=True)
assert cbrt(p**2) == p**Rational(2, 3)
assert NS(((0.2 + 0.7*I)**(0.7 + 1.0*I))**(0.5 - 0.1*I), 1) == '0.4 + 0.2*I'
assert sqrt(1/(1 + I)) == sqrt((1 - I)/2) # or 1/sqrt(1 + I)
e = 1/(1 - sqrt(2))
assert sqrt(e) == I/sqrt(-1 + sqrt(2))
assert e**Rational(-1, 2) == -I*sqrt(-1 + sqrt(2))
assert sqrt((cos(1)**2 + sin(1)**2 - 1)**(3 + I)).exp == Rational(1, 2)
assert sqrt(r**Rational(4, 3)) != r**Rational(2, 3)
assert sqrt((p + I)**Rational(4, 3)) == (p + I)**Rational(2, 3)
assert sqrt((p - p**2*I)**2) == p - p**2*I
assert sqrt((p + r*I)**2) != p + r*I
e = (1 + I/5)
assert sqrt(e**5) == e**Rational(5, 2)
assert sqrt(e**6) == e**3
assert sqrt((1 + I*r)**6) != (1 + I*r)**3
def test_sympyissue_6653():
assert (1 / sqrt(1 + sin(x**2))).series(x, 0, 3) == 1 - x**2/2 + O(x**3)
def test_dispersion():
pytest.raises(ValueError, lambda: dispersionset(poly(x*y, x, y),
poly(x, x)))
pytest.raises(ValueError, lambda: dispersionset(poly(x, x),
poly(y, y)))
fp = poly(0, x)
assert sorted(dispersionset(fp)) == [0]
fp = poly(2, x)
assert sorted(dispersionset(fp)) == [0]
fp = poly(x + 1, x)
assert sorted(dispersionset(fp)) == [0]
assert dispersion(fp) == 0
fp = poly((x + 1)*(x + 2), x)
assert sorted(dispersionset(fp)) == [0, 1]
assert dispersion(fp) == 1
fp = poly(x*(x + 3), x)
assert sorted(dispersionset(fp)) == [0, 3]
assert dispersion(fp) == 3
fp = poly((x - 3)*(x + 3), x)
assert sorted(dispersionset(fp)) == [0, 6]
assert dispersion(fp) == 6
fp = poly(x**4 - 3*x**2 + 1, x)
gp = fp.shift(-3)
assert sorted(dispersionset(fp, gp)) == [2, 3, 4]
assert dispersion(fp, gp) == 4
assert sorted(dispersionset(gp, fp)) == []
assert dispersion(gp, fp) == -oo
fp = poly(x**2 + 2*x - 1, x)
gp = poly(x**2 + 2*x + 3, x)
assert dispersionset(fp, gp) == set()
fp = poly(x*(3*x**2+a)*(x-2536)*(x**3+a), x)
gp = fp.as_expr().subs({x: x - 345}).as_poly(x)
assert sorted(dispersionset(fp, gp)) == [345, 2881]
assert sorted(dispersionset(gp, fp)) == [2191]
gp = poly((x-2)**2*(x-3)**3*(x-5)**3, x)
assert sorted(dispersionset(gp)) == [0, 1, 2, 3]
assert sorted(dispersionset(gp, (gp+4)**2)) == [1, 2]
fp = poly(x*(x+2)*(x-1), x)
assert sorted(dispersionset(fp)) == [0, 1, 2, 3]
fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ<sqrt(5)>')
gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ<sqrt(5)>')
assert sorted(dispersionset(fp, gp)) == [2]
assert sorted(dispersionset(gp, fp)) == [1, 4]
# There are some difficulties if we compute over Z[a]
# and alpha happenes to lie in Z[a] instead of simply Z.
# Hence we can not decide if alpha is indeed integral
# in general.
fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x)
assert sorted(dispersionset(fp)) == [0, 1]
# For any specific value of a, the dispersion is 3*a
# but the algorithm can not find this in general.
# This is the point where the resultant based Ansatz
# is superior to the current one.
fp = poly(a**2*x**3 + (a**3 + a**2 + a + 1)*x, x)
gp = fp.as_expr().subs({x: x - 3*a}).as_poly(x)
assert sorted(dispersionset(fp, gp)) == []
fpa = fp.as_expr().subs({a: 2}).as_poly(x)
gpa = gp.as_expr().subs({a: 2}).as_poly(x)
assert sorted(dispersionset(fpa, gpa)) == [6]
# Work with Expr instead of Poly
f = (x + 1)*(x + 2)
assert sorted(dispersionset(f)) == [0, 1]
assert dispersion(f) == 1
f = x**4 - 3*x**2 + 1
g = x**4 - 12*x**3 + 51*x**2 - 90*x + 55
assert sorted(dispersionset(f, g)) == [2, 3, 4]
assert dispersion(f, g) == 4
# Work with Expr and specify a generator
f = (x + 1)*(x + 2)
assert sorted(dispersionset(f, None, x)) == [0, 1]
assert dispersion(f, None, x) == 1
f = x**4 - 3*x**2 + 1
g = x**4 - 12*x**3 + 51*x**2 - 90*x + 55
assert sorted(dispersionset(f, g, x)) == [2, 3, 4]
assert dispersion(f, g, x) == 4
def test_sympyissue_4362():
neg = Symbol('neg', negative=True)
nonneg = Symbol('nonneg', nonnegative=True)
any = Symbol('any')
num, den = sqrt(1/neg).as_numer_denom()
assert num == sqrt(-1)
assert den == sqrt(-neg)
num, den = sqrt(1/nonneg).as_numer_denom()
assert num == 1
assert den == sqrt(nonneg)
num, den = sqrt(1/any).as_numer_denom()
assert num == sqrt(1/any)
assert den == 1
def eqn(num, den, pow):
return (num/den)**pow
npos = 1
nneg = -1
dpos = 2 - sqrt(3)
dneg = 1 - sqrt(3)
assert dpos > 0 and dneg < 0 and npos > 0 and nneg < 0
# pos or neg integer
eq = eqn(npos, dpos, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dpos**2)
eq = eqn(npos, dneg, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dneg**2)
eq = eqn(nneg, dpos, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dpos**2)
eq = eqn(nneg, dneg, 2)
assert eq.is_Pow and eq.as_numer_denom() == (1, dneg**2)
eq = eqn(npos, dpos, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**2, 1)
eq = eqn(npos, dneg, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dneg**2, 1)
eq = eqn(nneg, dpos, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**2, 1)
eq = eqn(nneg, dneg, -2)
assert eq.is_Pow and eq.as_numer_denom() == (dneg**2, 1)
# pos or neg rational
pow = Rational(1, 2)
eq = eqn(npos, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (npos**pow, dpos**pow)
eq = eqn(npos, dneg, pow)
assert eq.is_Pow is False and eq.as_numer_denom() == ((-npos)**pow, (-dneg)**pow)
eq = eqn(nneg, dpos, pow)
assert not eq.is_Pow or eq.as_numer_denom() == (nneg**pow, dpos**pow)
eq = eqn(nneg, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-nneg)**pow, (-dneg)**pow)
eq = eqn(npos, dpos, -pow)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**pow, npos**pow)
eq = eqn(npos, dneg, -pow)
assert eq.is_Pow is False and eq.as_numer_denom() == (-(-npos)**pow*(-dneg)**pow, npos)
eq = eqn(nneg, dpos, -pow)
assert not eq.is_Pow or eq.as_numer_denom() == (dpos**pow, nneg**pow)
eq = eqn(nneg, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-nneg)**pow)
# unknown exponent
pow = 2*any
eq = eqn(npos, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (npos**pow, dpos**pow)
eq = eqn(npos, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-npos)**pow, (-dneg)**pow)
eq = eqn(nneg, dpos, pow)
assert eq.is_Pow and eq.as_numer_denom() == (nneg**pow, dpos**pow)
eq = eqn(nneg, dneg, pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-nneg)**pow, (-dneg)**pow)
eq = eqn(npos, dpos, -pow)
assert eq.as_numer_denom() == (dpos**pow, npos**pow)
eq = eqn(npos, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-npos)**pow)
eq = eqn(nneg, dpos, -pow)
assert eq.is_Pow and eq.as_numer_denom() == (dpos**pow, nneg**pow)
eq = eqn(nneg, dneg, -pow)
assert eq.is_Pow and eq.as_numer_denom() == ((-dneg)**pow, (-nneg)**pow)
assert ((1/(1 + x/3))**-1).as_numer_denom() == (3 + x, 3)
notp = Symbol('notp', positive=False) # not positive does not imply real
b = ((1 + x/notp)**-2)
assert (b**(-y)).as_numer_denom() == (1, b**y)
assert (b**-1).as_numer_denom() == ((notp + x)**2, notp**2)
nonp = Symbol('nonp', nonpositive=True)
assert (((1 + x/nonp)**-2)**-1).as_numer_denom() == ((-nonp - x)**2,
nonp**2)
n = Symbol('n', negative=True)
assert (x**n).as_numer_denom() == (1, x**-n)
assert sqrt(1/n).as_numer_denom() == (I, sqrt(-n))
n = Symbol('0 or neg', nonpositive=True)
# if x and n are split up without negating each term and n is negative
# then the answer might be wrong; if n is 0 it won't matter since
# 1/oo and 1/zoo are both zero as is sqrt(0)/sqrt(-x) unless x is also
# zero (in which case the negative sign doesn't matter):
# 1/sqrt(1/-1) = -I but sqrt(-1)/sqrt(1) = I
assert (1/sqrt(x/n)).as_numer_denom() == (sqrt(-n), sqrt(-x))
c = Symbol('c', complex=True)
e = sqrt(1/c)
assert e.as_numer_denom() == (e, 1)
i = Symbol('i', integer=True)
assert (((1 + x/y)**i)).as_numer_denom() == ((x + y)**i, y**i)
