def _eval_evalf(self, prec):
# The default code is insufficient for polar arguments.
# mpmath provides an optional argument "r", which evaluates
# G(z**(1/r)). I am not sure what its intended use is, but we hijack it
# here in the following way: to evaluate at a number z of |argument|
# less than (say) n*pi, we put r=1/n, compute z' = root(z, n)
# (carefully so as not to loose the branch information), and evaluate
# G(z'**(1/r)) = G(z'**n) = G(z).
import mpmath
znum = self.argument._eval_evalf(prec)
if znum.has(exp_polar):
znum, branch = znum.as_coeff_mul(exp_polar)
if len(branch) != 1:
return
branch = branch[0].args[0] / I
else:
branch = S.Zero
n = ceiling(abs(branch / S.Pi)) + 1
znum = znum**(S.One / n) * exp(I * branch / n)
# Convert all args to mpf or mpc
try:
[z, r, ap, bq] = [
arg._to_mpmath(prec)
for arg in [znum, 1 / n, self.args[0], self.args[1]]
]
except ValueError:
return
with mpmath.workprec(prec):
v = mpmath.meijerg(ap, bq, z, r)
return Expr._from_mpmath(v, prec)
def _eval_evalf(self, prec):
if all(x.is_number for x in self.args):
a = self.args[0]._to_mpmath(prec)
z = self.args[1]._to_mpmath(prec)
with workprec(prec):
res = mp.gammainc(a, z, mp.inf)
return Expr._from_mpmath(res, prec)
return self
def _eval_evalf(self, prec):
# Note: works without this function by just calling
# mpmath for Legendre polynomials. But using
# the dedicated function directly is cleaner.
from mpmath import mp, workprec
n = self.args[0]._to_mpmath(prec)
m = self.args[1]._to_mpmath(prec)
theta = self.args[2]._to_mpmath(prec)
phi = self.args[3]._to_mpmath(prec)
with workprec(prec):
res = mp.spherharm(n, m, theta, phi)
return Expr._from_mpmath(res, prec)
def test_issue_5486_bug():
from sympy.core.expr import Expr
from sympy.core.numbers import I
assert abs(Expr._from_mpmath(I._to_mpmath(15), 15) - I) < 1.0e-15
