import tensorflow as tf

        b_soft_no_learn = np.array(
          [0.25, 0.25] + [-0.25] * (self.num_branches - 2), dtype=np.float32)
        b_soft_no_learn = np.reshape(b_soft_no_learn, [1, self.num_branches])
        self.b_soft_no_learn = tf.constant(b_soft_no_learn, dtype=tf.float32)

      with tf.variable_scope("attention"):
        self.w_attn_1 = tf.get_variable("w_1", [self.lstm_size, self.lstm_size])
        self.w_attn_2 = tf.get_variable("w_2", [self.lstm_size, self.lstm_size])
        self.v_attn = tf.get_variable("v", [self.lstm_size, 1])

  def _build_sampler(self, prev_c=None, prev_h=None, use_bias=False):
    """Build the sampler ops and the log_prob ops."""

    print ("-" * 80)
