lattice-prune.cc
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// latbin/lattice-prune.cc
// Copyright 2009-2013 Microsoft Corporation
// Johns Hopkins University (author: Daniel Povey)
// 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 "fstext/fstext-lib.h"
#include "lat/kaldi-lattice.h"
#include "lat/lattice-functions.h"
int main(int argc, char *argv[]) {
try {
using namespace kaldi;
typedef kaldi::int32 int32;
typedef kaldi::int64 int64;
using fst::SymbolTable;
using fst::VectorFst;
using fst::StdArc;
const char *usage =
"Apply beam pruning to lattices\n"
"Usage: lattice-prune [options] lattice-rspecifier lattice-wspecifier\n"
" e.g.: lattice-prune --acoustic-scale=0.1 --beam=4.0 ark:1.lats ark:pruned.lats\n";
ParseOptions po(usage);
BaseFloat acoustic_scale = 1.0;
BaseFloat inv_acoustic_scale = 1.0;
BaseFloat beam = 10.0;
po.Register("acoustic-scale", &acoustic_scale, "Scaling factor for acoustic likelihoods");
po.Register("inv-acoustic-scale", &inv_acoustic_scale, "An alternative way of setting the "
"acoustic scale: you can set its inverse.");
po.Register("beam", &beam, "Pruning beam [applied after acoustic scaling]");
po.Read(argc, argv);
if (po.NumArgs() != 2) {
po.PrintUsage();
exit(1);
}
KALDI_ASSERT(acoustic_scale == 1.0 || inv_acoustic_scale == 1.0);
if (inv_acoustic_scale != 1.0)
acoustic_scale = 1.0 / inv_acoustic_scale;
std::string lats_rspecifier = po.GetArg(1),
lats_wspecifier = po.GetArg(2);
SequentialCompactLatticeReader compact_lattice_reader(lats_rspecifier);
CompactLatticeWriter compact_lattice_writer(lats_wspecifier);
int32 n_done = 0, n_err = 0;
int64 n_arcs_in = 0, n_arcs_out = 0,
n_states_in = 0, n_states_out = 0;
if (acoustic_scale == 0.0)
KALDI_ERR << "Do not use a zero acoustic scale (cannot be inverted)";
for (; !compact_lattice_reader.Done(); compact_lattice_reader.Next()) {
std::string key = compact_lattice_reader.Key();
CompactLattice clat = compact_lattice_reader.Value();
compact_lattice_reader.FreeCurrent();
fst::ScaleLattice(fst::AcousticLatticeScale(acoustic_scale), &clat);
int64 narcs = NumArcs(clat), nstates = clat.NumStates();
n_arcs_in += narcs;
n_states_in += nstates;
CompactLattice pruned_clat(clat);
if (!PruneLattice(beam, &pruned_clat)) {
KALDI_WARN << "Error pruning lattice for utterance " << key;
n_err++;
}
int64 pruned_narcs = NumArcs(pruned_clat),
pruned_nstates = pruned_clat.NumStates();
n_arcs_out += pruned_narcs;
n_states_out += pruned_nstates;
KALDI_LOG << "For utterance " << key << ", pruned #states from "
<< nstates << " to " << pruned_nstates << " and #arcs from "
<< narcs << " to " << pruned_narcs;
fst::ScaleLattice(fst::AcousticLatticeScale(1.0/acoustic_scale), &pruned_clat);
compact_lattice_writer.Write(key, pruned_clat);
n_done++;
}
BaseFloat den = (n_done > 0 ? static_cast<BaseFloat>(n_done) : 1.0);
KALDI_LOG << "Overall, pruned from on average " << (n_states_in/den) << " to "
<< (n_states_out/den) << " states, and from " << (n_arcs_in/den)
<< " to " << (n_arcs_out/den) << " arcs, over " << n_done
<< " utterances.";
KALDI_LOG << "Done " << n_done << " lattices.";
return (n_done != 0 ? 0 : 1);
} catch(const std::exception &e) {
std::cerr << e.what();
return -1;
}
}