Calculates the full beams for `TensorArray`s.
gather_tree_from_array(t, parent_ids, sequence_length)
| t | A stacked `TensorArray` of size `max_time` that contains `Tensor`s of shape `[batch_size, beam_width, s]` or `[batch_size * beam_width, s]` where `s` is the depth shape. |
|---|---|
| parent_ids | The parent ids of shape `[max_time, batch_size, beam_width]`. |
| sequence_length | The sequence length of shape `[batch_size, beam_width]`. |
A `Tensor` which is a stacked `TensorArray` of the same size and type as `t` and where beams are sorted in each `Tensor` according to `parent_ids`.