ZeroMeanGaussObsModel.py 文件源码

def c_Diff(nu1, logdetB1, D, nu2, logdetB2):
    ''' Evaluate difference of cumulant functions c(params1) - c(params2)

    May be more numerically stable than directly using c_Func
    to find the difference.

    Returns
    -------
    diff : scalar real value of the difference in cumulant functions
    '''
    if logdetB1.ndim >= 2:
        assert D == logdetB1.shape[-1]
        logdetB1 = np.log(np.linalg.det(logdetB1))
        logdetB2 = np.log(np.linalg.det(logdetB2))
    dvec = np.arange(1, D + 1, dtype=np.float)
    return - 0.5 * D * LOGTWO * (nu1 - nu2) \
        - np.sum(gammaln(0.5 * (nu1 + 1 - dvec))) \
        + np.sum(gammaln(0.5 * (nu2 + 1 - dvec))) \
        + 0.5 * (nu1 * logdetB1 - nu2 * logdetB2)