model.py 文件源码

def _reverse_seq(input_seq, lengths):
    """Reverse a list of Tensors up to specified lengths.
    Args:
        input_seq: Sequence of seq_len tensors of dimension (batch_size, depth)
        lengths:   A tensor of dimension batch_size, containing lengths for each
                   sequence in the batch. If "None" is specified, simply reverses
                   the list.
    Returns:
        time-reversed sequence
    """
    for input_ in input_seq:
        input_.set_shape(input_.get_shape().with_rank(2))

    # Join into (time, batch_size, depth)
    s_joined = array_ops_.pack(input_seq)

    # Reverse along dimension 0
    s_reversed = array_ops_.reverse_sequence(s_joined, lengths, 0, 1)
    # Split again into list
    result = array_ops_.unpack(s_reversed)
    return result