// gmmbin/gmm-latgen-faster-parallel.cc
  
  // Copyright 2009-2012  Microsoft Corporation
  //                      Johns Hopkins University (author: Daniel Povey)
  //                2014  Guoguo Chen
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  // THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  // WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  // MERCHANTABLITY OR NON-INFRINGEMENT.
  // See the Apache 2 License for the specific language governing permissions and
  // limitations under the License.
  
  
  #include "base/kaldi-common.h"
  #include "util/common-utils.h"
  #include "gmm/am-diag-gmm.h"
  #include "tree/context-dep.h"
  #include "hmm/transition-model.h"
  #include "fstext/fstext-lib.h"
  #include "decoder/decoder-wrappers.h"
  #include "gmm/decodable-am-diag-gmm.h"
  #include "base/timer.h"
  #include "feat/feature-functions.h"  // feature reversal
  #include "util/kaldi-thread.h"
  
  
  int main(int argc, char *argv[]) {
    try {
      using namespace kaldi;
      typedef kaldi::int32 int32;
      using fst::SymbolTable;
      using fst::VectorFst;
      using fst::Fst;
      using fst::StdArc;
  
      const char *usage =
          "Decode features using GMM-based model.  Uses multiple decoding threads,
  "
          "but interface and behavior is otherwise the same as gmm-latgen-faster
  "
          "Usage: gmm-latgen-faster-parallel [options] model-in (fst-in|fsts-rspecifier) "
          "features-rspecifier lattice-wspecifier [ words-wspecifier [alignments-wspecifier] ]
  ";
      ParseOptions po(usage);
      Timer timer;
      bool allow_partial = false;
      BaseFloat acoustic_scale = 0.1;
      BaseFloat log_sum_exp_prune = 0.0;
      LatticeFasterDecoderConfig latgen_config;
      TaskSequencerConfig sequencer_config; // has --num-threads option
  
      std::string word_syms_filename;
      latgen_config.Register(&po);
      sequencer_config.Register(&po);
      po.Register("acoustic-scale", &acoustic_scale,
                  "Scaling factor for acoustic likelihoods");
      po.Register("log-sum-exp-prune", &log_sum_exp_prune,
                  "If >0, pruning parameter to minimize exp()'s.  Suggest 3 to 5; "
                  "larger is more exact.");
      po.Register("word-symbol-table", &word_syms_filename,
                  "Symbol table for words [for debug output]");
      po.Register("allow-partial", &allow_partial,
                  "If true, produce output even if end state was not reached.");
  
      po.Read(argc, argv);
  
      if (po.NumArgs() < 4 || po.NumArgs() > 6) {
        po.PrintUsage();
        exit(1);
      }
  
      std::string model_in_filename = po.GetArg(1),
          fst_in_str = po.GetArg(2),
          feature_rspecifier = po.GetArg(3),
          lattice_wspecifier = po.GetArg(4),
          words_wspecifier = po.GetOptArg(5),
          alignment_wspecifier = po.GetOptArg(6);
  
      TransitionModel trans_model;
      AmDiagGmm am_gmm;
      {
        bool binary;
        Input ki(model_in_filename, &binary);
        trans_model.Read(ki.Stream(), binary);
        am_gmm.Read(ki.Stream(), binary);
      }
  
      bool determinize = latgen_config.determinize_lattice;
      CompactLatticeWriter compact_lattice_writer;
      LatticeWriter lattice_writer;
      if (! (determinize ? compact_lattice_writer.Open(lattice_wspecifier)
             : lattice_writer.Open(lattice_wspecifier)))
        KALDI_ERR << "Could not open table for writing lattices: "
                   << lattice_wspecifier;
  
      Int32VectorWriter words_writer(words_wspecifier);
  
      Int32VectorWriter alignment_writer(alignment_wspecifier);
  
      fst::SymbolTable *word_syms = NULL;
      if (word_syms_filename != "")
        if (!(word_syms = fst::SymbolTable::ReadText(word_syms_filename)))
          KALDI_ERR << "Could not read symbol table from file "
                     << word_syms_filename;
  
      double tot_like = 0.0;
      kaldi::int64 frame_count = 0;
      int num_done = 0, num_err = 0;
      Fst<StdArc> *decode_fst = NULL; // only used if there is a single
                                            // decoding graph.
  
      TaskSequencer<DecodeUtteranceLatticeFasterClass> sequencer(sequencer_config);
  
      if (ClassifyRspecifier(fst_in_str, NULL, NULL) == kNoRspecifier) {
        SequentialBaseFloatMatrixReader feature_reader(feature_rspecifier);
        // Input FST is just one FST, not a table of FSTs.
  
        decode_fst = fst::ReadFstKaldiGeneric(fst_in_str);
        timer.Reset();
  
        {
          for (; !feature_reader.Done(); feature_reader.Next()) {
            std::string utt = feature_reader.Key();
            Matrix<BaseFloat> *features =
                new Matrix<BaseFloat>(feature_reader.Value());
            feature_reader.FreeCurrent();
            if (features->NumRows() == 0) {
              KALDI_WARN << "Zero-length utterance: " << utt;
              num_err++;
              delete features;
              continue;
            }
  
            LatticeFasterDecoder *decoder = new LatticeFasterDecoder(*decode_fst,
                                                                     latgen_config);
            // takes ownership of "features"
            DecodableAmDiagGmmScaled *gmm_decodable =
                new DecodableAmDiagGmmScaled(am_gmm, trans_model,
                                             acoustic_scale,
                                             log_sum_exp_prune,
                                             features);
  
            DecodeUtteranceLatticeFasterClass *task =
                new DecodeUtteranceLatticeFasterClass(
                    decoder, gmm_decodable, // takes ownership of these two.
                    trans_model, word_syms, utt, acoustic_scale, determinize,
                    allow_partial, &alignment_writer, &words_writer,
                    &compact_lattice_writer, &lattice_writer,
                    &tot_like, &frame_count, &num_done, &num_err, NULL);
  
            sequencer.Run(task); // takes ownership of "task",
            // and will delete it when done.
          }
        }
      } else { // We have different FSTs for different utterances.
        SequentialTableReader<fst::VectorFstHolder> fst_reader(fst_in_str);
        RandomAccessBaseFloatMatrixReader feature_reader(feature_rspecifier);
        for (; !fst_reader.Done(); fst_reader.Next()) {
          std::string utt = fst_reader.Key();
          if (!feature_reader.HasKey(utt)) {
            KALDI_WARN << "Not decoding utterance " << utt
                       << " because no features available.";
            num_err++;
            continue;
          }
          Matrix<BaseFloat> *features = new Matrix<BaseFloat>(
              feature_reader.Value(utt));
          if (features->NumRows() == 0) {
            KALDI_WARN << "Zero-length utterance: " << utt;
            num_err++;
            delete features;
            continue;
          }
  
          // the "decoder" object takes ownership of the new FST object.
          LatticeFasterDecoder *decoder = new LatticeFasterDecoder(
              latgen_config,
              new VectorFst<StdArc>(fst_reader.Value()));
  
          // The "decodable" object takes ownership of the features.
          DecodableAmDiagGmmScaled *gmm_decodable =
              new DecodableAmDiagGmmScaled(am_gmm, trans_model, acoustic_scale,
                                           log_sum_exp_prune, features);
  
          DecodeUtteranceLatticeFasterClass *task =
              new DecodeUtteranceLatticeFasterClass(
                  decoder, gmm_decodable, // takes ownership of these two.
                  trans_model, word_syms, utt, acoustic_scale, determinize,
                  allow_partial, &alignment_writer, &words_writer,
                  &compact_lattice_writer, &lattice_writer,
                  &tot_like, &frame_count, &num_done, &num_err, NULL);
          sequencer.Run(task); // takes ownership of "task",
          // and will delete it when done.
        }
      }
      sequencer.Wait();
  
      delete decode_fst;
  
      double elapsed = timer.Elapsed();
      KALDI_LOG << "Decoded with " << sequencer_config.num_threads << " threads.";
      KALDI_LOG << "Time taken "<< elapsed
                << "s: real-time factor per thread assuming 100 frames/sec is "
                << (sequencer_config.num_threads * elapsed * 100.0 / frame_count);
      KALDI_LOG << "Done " << num_done << " utterances, failed for "
                << num_err;
      KALDI_LOG << "Overall log-likelihood per frame is "
                << (tot_like/frame_count) << " over "
                << frame_count << " frames.";
  
      delete word_syms;
      if (num_done != 0) return 0;
      else return 1;
    } catch(const std::exception &e) {
      std::cerr << e.what();
      return -1;
    }
  }