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- from __future__ import division, print_function, absolute_import
- import numpy as np
- from numpy.testing import assert_allclose, assert_
- from scipy.special._testutils import FuncData
- from scipy.special import gamma, gammaln, loggamma
- def test_identities1():
- # test the identity exp(loggamma(z)) = gamma(z)
- x = np.array([-99.5, -9.5, -0.5, 0.5, 9.5, 99.5])
- y = x.copy()
- x, y = np.meshgrid(x, y)
- z = (x + 1J*y).flatten()
- dataset = np.vstack((z, gamma(z))).T
- def f(z):
- return np.exp(loggamma(z))
- FuncData(f, dataset, 0, 1, rtol=1e-14, atol=1e-14).check()
- def test_identities2():
- # test the identity loggamma(z + 1) = log(z) + loggamma(z)
- x = np.array([-99.5, -9.5, -0.5, 0.5, 9.5, 99.5])
- y = x.copy()
- x, y = np.meshgrid(x, y)
- z = (x + 1J*y).flatten()
- dataset = np.vstack((z, np.log(z) + loggamma(z))).T
- def f(z):
- return loggamma(z + 1)
- FuncData(f, dataset, 0, 1, rtol=1e-14, atol=1e-14).check()
- def test_complex_dispatch_realpart():
- # Test that the real parts of loggamma and gammaln agree on the
- # real axis.
- x = np.r_[-np.logspace(10, -10), np.logspace(-10, 10)] + 0.5
- dataset = np.vstack((x, gammaln(x))).T
- def f(z):
- z = np.array(z, dtype='complex128')
- return loggamma(z).real
- FuncData(f, dataset, 0, 1, rtol=1e-14, atol=1e-14).check()
- def test_real_dispatch():
- x = np.logspace(-10, 10) + 0.5
- dataset = np.vstack((x, gammaln(x))).T
- FuncData(loggamma, dataset, 0, 1, rtol=1e-14, atol=1e-14).check()
- assert_(loggamma(0) == np.inf)
- assert_(np.isnan(loggamma(-1)))
- def test_gh_6536():
- z = loggamma(complex(-3.4, +0.0))
- zbar = loggamma(complex(-3.4, -0.0))
- assert_allclose(z, zbar.conjugate(), rtol=1e-15, atol=0)
- def test_branch_cut():
- # Make sure negative zero is treated correctly
- x = -np.logspace(300, -30, 100)
- z = np.asarray([complex(x0, 0.0) for x0 in x])
- zbar = np.asarray([complex(x0, -0.0) for x0 in x])
- assert_allclose(z, zbar.conjugate(), rtol=1e-15, atol=0)
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