wehub-resource-sync
95 lines
2.9 KiB
C++
95 lines
2.9 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#include <iostream>
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#include "fstext/fstext-lib.h" // @manual
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#include "util/common-utils.h" // @manual
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/*
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* This program is to modify a FST without self-loop by:
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* for each incoming arc with non-eps input symbol, add a self-loop arc
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* with that non-eps symbol as input and eps as output.
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*
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* This is to make sure the resultant FST can do deduplication for repeated
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* symbols, which is very common in acoustic model
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*
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*/
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namespace {
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int32 AddSelfLoopsSimple(fst::StdVectorFst* fst) {
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typedef fst::MutableArcIterator<fst::StdVectorFst> IterType;
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int32 num_states_before = fst->NumStates();
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fst::MakePrecedingInputSymbolsSame(false, fst);
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int32 num_states_after = fst->NumStates();
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KALDI_LOG << "There are " << num_states_before
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<< " states in the original FST; "
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<< " after MakePrecedingInputSymbolsSame, there are "
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<< num_states_after << " states " << std::endl;
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auto weight_one = fst::StdArc::Weight::One();
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int32 num_arc_added = 0;
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fst::StdArc self_loop_arc;
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self_loop_arc.weight = weight_one;
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int32 num_states = fst->NumStates();
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std::vector<std::set<int32>> incoming_non_eps_label_per_state(num_states);
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for (int32 state = 0; state < num_states; state++) {
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for (IterType aiter(fst, state); !aiter.Done(); aiter.Next()) {
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fst::StdArc arc(aiter.Value());
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if (arc.ilabel != 0) {
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incoming_non_eps_label_per_state[arc.nextstate].insert(arc.ilabel);
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}
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}
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}
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for (int32 state = 0; state < num_states; state++) {
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if (!incoming_non_eps_label_per_state[state].empty()) {
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auto& ilabel_set = incoming_non_eps_label_per_state[state];
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for (auto it = ilabel_set.begin(); it != ilabel_set.end(); it++) {
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self_loop_arc.ilabel = *it;
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self_loop_arc.olabel = 0;
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self_loop_arc.nextstate = state;
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fst->AddArc(state, self_loop_arc);
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num_arc_added++;
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}
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}
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}
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return num_arc_added;
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}
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void print_usage() {
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std::cout << "add-self-loop-simple usage:\n"
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"\tadd-self-loop-simple <in-fst> <out-fst> \n";
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}
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} // namespace
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int main(int argc, char** argv) {
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if (argc != 3) {
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print_usage();
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exit(1);
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}
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auto input = argv[1];
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auto output = argv[2];
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auto fst = fst::ReadFstKaldi(input);
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auto num_states = fst->NumStates();
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KALDI_LOG << "Loading FST from " << input << " with " << num_states
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<< " states." << std::endl;
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int32 num_arc_added = AddSelfLoopsSimple(fst);
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KALDI_LOG << "Adding " << num_arc_added << " self-loop arcs " << std::endl;
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fst::WriteFstKaldi(*fst, std::string(output));
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KALDI_LOG << "Writing FST to " << output << std::endl;
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delete fst;
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}
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