test_comparisons.py 文件源码

def test_dic_posterior_dependence():
    d = norm.rvs(size=1000000)
    p = norm.logpdf(d)
    p2 = norm.logpdf(d, scale=2)
    c = ChainConsumer()
    c.add_chain(d, posterior=p)
    c.add_chain(d, posterior=p2)
    bics = c.comparison.dic()
    assert len(bics) == 2
    assert bics[1] == 0
    dic1 = 2 * np.mean(-2 * p) + 2 * norm.logpdf(0)
    dic2 = 2 * np.mean(-2 * p2) + 2 * norm.logpdf(0, scale=2)
    assert np.isclose(bics[0], dic1 - dic2, atol=1e-3)