tf.contrib.seq2seq.gather_tree

Calculates the full beams from the per-step ids and parent beam ids.

tf.contrib.seq2seq.gather_tree(
    step_ids, parent_ids, max_sequence_lengths, end_token, name=None
)

On CPU, if an out of bound parent id is found, an error is returned. On GPU, if an out of bound parent id is found, a -1 is stored in the corresponding output value and the execution for that beam returns early.

For a given beam, past the time step containing the first decoded end_token all values are filled in with end_token.

Args
step_ids	A Tensor. Must be one of the following types: int32. [max_time, batch_size, beam_width].
parent_ids	A Tensor. Must have the same type as step_ids. [max_time, batch_size, beam_width].
max_sequence_lengths	A Tensor of type int32. [batch_size].
end_token	A Tensor. Must have the same type as step_ids. [].
name	A name for the operation (optional).

Returns
A Tensor. Has the same type as step_ids. [max_time, batch_size, beam_width].