util.py 文件源码

def gaussian_logp(x, mu, ln_var):
    """log N(x ; mu, var)"""
    batch_size = mu.data.shape[0]
    D = x.data.size
    S = F.exp(ln_var)
    xc = x - mu

    logp_sum = -0.5*(F.sum((xc*xc) / S, axis=1) + F.sum(ln_var, axis=1)
        + D/batch_size*math.log(2.0*math.pi))

    return logp_sum