import tensorflow as tf

        update_eps_ph = tf.placeholder(tf.float32, (), name="update_eps")

        eps = tf.get_variable("eps", (), initializer=tf.constant_initializer(0))

        q_values = q_func(observations_ph.get(), num_actions, scope="q_func")
        deterministic_actions = tf.argmax(q_values, axis=1)

        batch_size = tf.shape(observations_ph.get())[0]
        random_actions = tf.random_uniform(tf.stack([batch_size]), minval=0, maxval=num_actions, dtype=tf.int64)
        chose_random = tf.random_uniform(tf.stack([batch_size]), minval=0, maxval=1, dtype=tf.float32) < eps
        stochastic_actions = tf.where(chose_random, random_actions, deterministic_actions)

        output_actions = tf.cond(stochastic_ph, lambda: stochastic_actions, lambda: deterministic_actions)
        update_eps_expr = eps.assign(tf.cond(update_eps_ph >= 0, lambda: update_eps_ph, lambda: eps))
        _act = U.function(inputs=[observations_ph, stochastic_ph, update_eps_ph],
                         outputs=output_actions,
