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from __future__ import division, print_function, absolute_import
from scipy.stats import hypergeom, bernoulli
import numpy as np
from numpy.testing import assert_almost_equal
def test_hypergeom_logpmf():
# symmetries test
# f(k,N,K,n) = f(n-k,N,N-K,n) = f(K-k,N,K,N-n) = f(k,N,n,K)
k = 5
N = 50
K = 10
n = 5
logpmf1 = hypergeom.logpmf(k,N,K,n)
logpmf2 = hypergeom.logpmf(n-k,N,N-K,n)
logpmf3 = hypergeom.logpmf(K-k,N,K,N-n)
logpmf4 = hypergeom.logpmf(k,N,n,K)
assert_almost_equal(logpmf1, logpmf2, decimal=12)
assert_almost_equal(logpmf1, logpmf3, decimal=12)
assert_almost_equal(logpmf1, logpmf4, decimal=12)
# test related distribution
# Bernoulli distribution if n = 1
k = 1
N = 10
K = 7
n = 1
hypergeom_logpmf = hypergeom.logpmf(k,N,K,n)
bernoulli_logpmf = bernoulli.logpmf(k,K/N)
assert_almost_equal(hypergeom_logpmf, bernoulli_logpmf, decimal=12)
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