message: Implement blank_index accepting negative values
diff: @@ -308,6 +308,10 @@ def ctc_greedy_decoder(inputs,
  sequence_length: 1-D `int32` vector containing sequence lengths, having size
  `[batch_size]`.
  merge_repeated: Boolean. Default: True.
  + blank_index: (optional) Set the class index to use for the blank label.
  + Negative values will start from num_classes, ie, -1 will reproduce the
  + ctc_greedy_decoder behavior of using num_classes - 1 for the blank symbol.
  +
  Returns:
  A tuple `(decoded, neg_sum_logits)` where
  @@ -330,6 +334,9 @@ def ctc_greedy_decoder(inputs,
  """
  if blank_index is not None:
  + if blank_index < 0:
  + blank_index += _get_dim(inputs, 2)
  +
  part_before = inputs[:, :, :blank_index]
  part_after = inputs[:, :, blank_index + 1:]
  part_blank = inputs[:, :, blank_index:blank_index + 1]
  