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