105 lines
4.5 KiB
C
105 lines
4.5 KiB
C
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// lat/lattice-functions-transition-model.h
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// Copyright 2009-2012 Saarland University (author: Arnab Ghoshal)
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// 2012-2013 Johns Hopkins University (Author: Daniel Povey);
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// Bagher BabaAli
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// 2014 Guoguo Chen
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// See ../../COPYING for clarification regarding multiple authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
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// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
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// MERCHANTABLITY OR NON-INFRINGEMENT.
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// See the Apache 2 License for the specific language governing permissions and
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// limitations under the License.
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#ifndef KALDI_LAT_LATTICE_FUNCTIONS_TRANSITION_MODEL_H_
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#define KALDI_LAT_LATTICE_FUNCTIONS_TRANSITION_MODEL_H_
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#include <map>
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#include <vector>
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#include "base/kaldi-common.h"
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#include "fstext/fstext-lib.h"
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#include "hmm/transition-model.h"
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#include "hmm/hmm-utils.h"
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#include "hmm/posterior.h"
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#include "itf/decodable-itf.h"
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#include "lat/kaldi-lattice.h"
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#include "lat/word-align-lattice-lexicon.h"
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namespace kaldi {
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/**
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This function can be used to compute posteriors for MMI, with a positive contribution
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for the numerator and a negative one for the denominator. This function is not actually
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used in our normal MMI training recipes, where it's instead done using various command
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line programs that each do a part of the job. This function was written for use in
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neural-net MMI training.
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@param [in] trans The transition model. Used to map the
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transition-ids to phones or pdfs.
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@param [in] lat The denominator lattice
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@param [in] num_ali The numerator alignment
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@param [in] drop_frames If "drop_frames" is true, it will not compute any
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posteriors on frames where the num and den have disjoint
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pdf-ids.
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@param [in] convert_to_pdf_ids If "convert_to_pdfs_ids" is true, it will
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convert the output to be at the level of pdf-ids, not
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transition-ids.
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@param [in] cancel If "cancel" is true, it will cancel out any positive and
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negative parts from the same transition-id (or pdf-id,
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if convert_to_pdf_ids == true).
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@param [out] arc_post The output MMI posteriors of transition-ids (or
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pdf-ids if convert_to_pdf_ids == true) at each frame
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i.e. the difference between the numerator
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and denominator posteriors.
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It returns the forward-backward likelihood of the lattice. */
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BaseFloat LatticeForwardBackwardMmi(
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const TransitionModel &trans,
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const Lattice &lat,
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const std::vector<int32> &num_ali,
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bool drop_frames,
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bool convert_to_pdf_ids,
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bool cancel,
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Posterior *arc_post);
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/// This function takes a CompactLattice that should only contain a single
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/// linear sequence (e.g. derived from lattice-1best), and that should have been
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/// processed so that the arcs in the CompactLattice align correctly with the
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/// word boundaries (e.g. by lattice-align-words). It outputs 4 vectors of the
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/// same size, which give, for each word in the lattice (in sequence), the word
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/// label, the begin time and length in frames, and the pronunciation (sequence
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/// of phones). This is done even for zero words, corresponding to optional
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/// silences -- if you don't want them, just ignore them in the output.
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/// This function will print a warning and return false, if the lattice
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/// did not have the correct format (e.g. if it is empty or it is not
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/// linear).
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bool CompactLatticeToWordProns(
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const TransitionModel &tmodel,
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const CompactLattice &clat,
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std::vector<int32> *words,
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std::vector<int32> *begin_times,
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std::vector<int32> *lengths,
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std::vector<std::vector<int32> > *prons,
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std::vector<std::vector<int32> > *phone_lengths);
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bool TestWordAlignedLattice(const WordAlignLatticeLexiconInfo &lexicon_info,
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const TransitionModel &tmodel,
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CompactLattice clat,
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CompactLattice aligned_clat,
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bool allow_duplicate_paths);
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} // namespace kaldi
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#endif // KALDI_LAT_LATTICE_FUNCTIONS_TRANSITION_MODEL_H_
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