Calculates the CTC Loss (log probability) for each batch entry. Also calculates

tf.raw_ops.CTCLoss( inputs, labels_indices, labels_values, sequence_length, preprocess_collapse_repeated=False, ctc_merge_repeated=True, ignore_longer_outputs_than_inputs=False, name=None )

the gradient. This class performs the softmax operation for you, so inputs should be e.g. linear projections of outputs by an LSTM.

Args | |
---|---|

`inputs` | A `Tensor` . Must be one of the following types: `float32` , `float64` . 3-D, shape: `(max_time x batch_size x num_classes)` , the logits. |

`labels_indices` | A `Tensor` of type `int64` . The indices of a `SparseTensor<int32, 2>` . `labels_indices(i, :) == [b, t]` means `labels_values(i)` stores the id for `(batch b, time t)` . |

`labels_values` | A `Tensor` of type `int32` . The values (labels) associated with the given batch and time. |

`sequence_length` | A `Tensor` of type `int32` . A vector containing sequence lengths (batch). |

`preprocess_collapse_repeated` | An optional `bool` . Defaults to `False` . Scalar, if true then repeated labels are collapsed prior to the CTC calculation. |

`ctc_merge_repeated` | An optional `bool` . Defaults to `True` . Scalar. If set to false, during CTC calculation repeated non-blank labels will not be merged and are interpreted as individual labels. This is a simplified version of CTC. |

`ignore_longer_outputs_than_inputs` | An optional `bool` . Defaults to `False` . Scalar. If set to true, during CTC calculation, items that have longer output sequences than input sequences are skipped: they don't contribute to the loss term and have zero-gradient. |

`name` | A name for the operation (optional). |

Returns | |
---|---|

A tuple of `Tensor` objects (loss, gradient). | |

`loss` | A `Tensor` . Has the same type as `inputs` . |

`gradient` | A `Tensor` . Has the same type as `inputs` . |

© 2020 The TensorFlow Authors. All rights reserved.

Licensed under the Creative Commons Attribution License 3.0.

Code samples licensed under the Apache 2.0 License.

https://www.tensorflow.org/versions/r2.4/api_docs/python/tf/raw_ops/CTCLoss