univariate.py 文件源码

def _log_prob(self, given):
        logits = self.logits
        n = tf.cast(self.n_experiments, self.param_dtype)
        given = tf.cast(given, self.param_dtype)

        log_1_minus_p = -tf.nn.softplus(logits)
        lgamma_n_plus_1 = tf.lgamma(n + 1)
        lgamma_given_plus_1 = tf.lgamma(given + 1)
        lgamma_n_minus_given_plus_1 = tf.lgamma(n - given + 1)

        if self._check_numerics:
            lgamma_given_plus_1 = tf.check_numerics(
                lgamma_given_plus_1, "lgamma(given + 1)")
            lgamma_n_minus_given_plus_1 = tf.check_numerics(
                lgamma_n_minus_given_plus_1, "lgamma(n - given + 1)")

        return lgamma_n_plus_1 - lgamma_n_minus_given_plus_1 - \
            lgamma_given_plus_1 + given * logits + n * log_1_minus_p