hmc.py 文件源码

def hmc_updates(initial_pos, stepsize, avg_acceptance_rate, final_pos, accept,
                target_acceptance_rate, stepsize_inc, stepsize_dec,
                stepsize_min, stepsize_max, avg_acceptance_slowness):
    new_pos = tf.where(accept, final_pos, initial_pos)
    new_stepsize_ = tf.multiply(
        stepsize,
        tf.where(tf.greater(avg_acceptance_rate, target_acceptance_rate), stepsize_inc, stepsize_dec)
    )
    new_stepsize = tf.maximum(tf.minimum(new_stepsize_, stepsize_max), stepsize_min)
    new_acceptance_rate = tf.add(
        avg_acceptance_slowness * avg_acceptance_rate,
        (1.0 - avg_acceptance_slowness) * tf.reduce_mean(tf.to_float(accept))
    )
    return new_pos, new_stepsize, new_acceptance_rate