seq2seq_helpers.py 文件源码

def shift_thin_stack(thin_stack, thin_stack_head_next, batch_size,
                     max_num_concepts, decoder_position, 
                     prev_transition_state):
  """Applies shift to the thin stack and its head if in shift state."""
  # Head points to item after stack top, so always update the stack entry.
  new_thin_stack = write_thin_stack(thin_stack, thin_stack_head_next,
      decoder_position, batch_size, max_num_concepts)

  # Push if previous transition state is shift (or pointer shift).
  stack_head_updates = tf.sparse_to_dense(tf.pack(
      [data_utils.GEN_STATE]),
      tf.pack([data_utils.NUM_TR_STATES]), 1)
  new_thin_stack_head_next = tf.add(thin_stack_head_next,
      tf.gather(stack_head_updates, prev_transition_state))

  return new_thin_stack, new_thin_stack_head_next