hmc.py 文件源码

def get_acceptance_rate(q, p, new_q, new_p, log_posterior, mass, data_axes):
    old_hamiltonian, old_log_prob = hamiltonian(
        q, p, log_posterior, mass, data_axes)
    new_hamiltonian, new_log_prob = hamiltonian(
        new_q, new_p, log_posterior, mass, data_axes)
    old_log_prob = tf.check_numerics(
        old_log_prob,
        'HMC: old_log_prob has numeric errors! Try better initialization.')
    acceptance_rate = tf.exp(
        tf.minimum(-new_hamiltonian + old_hamiltonian, 0.0))
    is_finite = tf.logical_and(tf.is_finite(acceptance_rate),
                               tf.is_finite(new_log_prob))
    acceptance_rate = tf.where(is_finite, acceptance_rate,
                               tf.zeros_like(acceptance_rate))
    return old_hamiltonian, new_hamiltonian, old_log_prob, new_log_prob, \
        acceptance_rate