import tensorflow as tf

            axis=0)  # operation of choosing action
        # 更新
        self.update_old_action_op_op = [
            olda.assign(a) for a, olda in zip(
                action_op_params, old_action_op_params)]
        # 定義輸入變數
        self.tfa = tf.placeholder(tf.float32, [None, action_dim], 'action')
        self.tfadv = tf.placeholder(tf.float32, [None, 1], 'advantage')
        # 機率比較
        ratio = action_op.prob(self.tfa) / \
            (old_action_op.prob(self.tfa) + 1e-5)
        # 替代損失
