diff options
Diffstat (limited to 'tensorflow/python/ops/ctc_ops.py')
| -rw-r--r-- | tensorflow/python/ops/ctc_ops.py | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/tensorflow/python/ops/ctc_ops.py b/tensorflow/python/ops/ctc_ops.py index bab9dc0ef5..2f85112172 100644 --- a/tensorflow/python/ops/ctc_ops.py +++ b/tensorflow/python/ops/ctc_ops.py @@ -48,6 +48,18 @@ def ctc_loss(inputs, labels, sequence_length, <= sequence_length(b) for all b. ``` + Notes: + + This class performs the softmax operation for you, so inputs should + be e.g. linear projections of outputs by an LSTM. + + The `inputs` Tensor's innermost dimension size, `num_classes`, represents + `num_labels + 1` classes, where num_labels is the number of true labels, and + the largest value `(num_classes - 1)` is reserved for the blank label. + + For example, for a vocabulary containing 3 labels `[a, b, c]`, + `num_classes = 4` and the labels indexing is `{a: 0, b: 1, c: 2, blank: 3}`. + Regarding the arguments `preprocess_collapse_repeated` and `ctc_merge_repeated`: @@ -84,10 +96,12 @@ def ctc_loss(inputs, labels, sequence_length, Args: inputs: 3-D `float` `Tensor` sized - `[max_time x batch_size x num_classes]`. The logits. + `[max_time x batch_size x num_classes]`. The logits. labels: An `int32` `SparseTensor`. `labels.indices[i, :] == [b, t]` means `labels.values[i]` stores - the id for (batch b, time t). See `core/ops/ctc_ops.cc` for more details. + the id for (batch b, time t). + `labels.values[i]` must take on values in `[0, num_labels)`. + See `core/ops/ctc_ops.cc` for more details. sequence_length: 1-D `int32` vector, size `[batch_size]`. The sequence lengths. preprocess_collapse_repeated: Boolean. Default: False. |