seq2seq_helpers.py 文件源码

def init_thin_stack(batch_size, max_num_concepts):
  """Initializes the thin stack.
  Returns:
    thin_stack: Tensor with the stack content.
    thin_stack_head_next: Index pointers to element after stack head.
  """
  # Stack initialized to -1, points to initial state.
  thin_stack = -tf.ones(tf.pack([batch_size, max_num_concepts]),
      dtype=tf.int32)
  # Reshape to ensure dimension 1 is known.
  thin_stack = tf.reshape(thin_stack, [-1, max_num_concepts])
  # Set to 0 at position 0.
  inds = tf.transpose(tf.to_int64(tf.pack(
   [tf.range(batch_size), tf.zeros(tf.pack([batch_size]), dtype=tf.int32)])))
  delta = tf.SparseTensor(inds, tf.ones(tf.pack([batch_size]), dtype=tf.int32),
      tf.pack([tf.to_int64(batch_size), max_num_concepts]))
  new_thin_stack = thin_stack + tf.sparse_tensor_to_dense(delta)
  # Position 0 is for empty stack; position after head always >= 1.
  thin_stack_head_next = tf.ones(tf.pack([batch_size]),
      dtype=tf.int32)
  return new_thin_stack, thin_stack_head_next