diff options
author | Ian Hodson <idh@google.com> | 2012-05-30 21:27:06 +0100 |
---|---|---|
committer | Ian Hodson <idh@google.com> | 2012-05-30 22:47:36 +0100 |
commit | f4c12fce1ee58e670f9c3fce46c40296ba9ee8a2 (patch) | |
tree | b131ed907f9b2d5af09c0983b651e9e69bc6aab9 /src/include/fst/rmfinalepsilon.h | |
parent | a92766f0a6ba4fac46cd6fd3856ef20c3b204f0d (diff) | |
download | openfst-f4c12fce1ee58e670f9c3fce46c40296ba9ee8a2.tar.gz |
Add openfst to external, as used by GoogleTTSandroid-sdk-support_r11android-cts-4.2_r2android-cts-4.2_r1android-cts-4.1_r4android-cts-4.1_r2android-cts-4.1_r1android-4.2_r1android-4.2.2_r1.2android-4.2.2_r1.1android-4.2.2_r1android-4.2.1_r1.2android-4.2.1_r1.1android-4.2.1_r1android-4.1.2_r2.1android-4.1.2_r2android-4.1.2_r1android-4.1.1_r6.1android-4.1.1_r6android-4.1.1_r5android-4.1.1_r4android-4.1.1_r3android-4.1.1_r2android-4.1.1_r1.1android-4.1.1_r1tools_r22tools_r21jb-releasejb-mr1.1-releasejb-mr1.1-dev-plus-aospjb-mr1.1-devjb-mr1-releasejb-mr1-dev-plus-aospjb-mr1-devjb-mr0-releasejb-dev
Moved from GoogleTTS
Change-Id: I6bc6bdadaa53bd0f810b88443339f6d899502cc8
Diffstat (limited to 'src/include/fst/rmfinalepsilon.h')
-rw-r--r-- | src/include/fst/rmfinalepsilon.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/include/fst/rmfinalepsilon.h b/src/include/fst/rmfinalepsilon.h new file mode 100644 index 0000000..236d1a7 --- /dev/null +++ b/src/include/fst/rmfinalepsilon.h @@ -0,0 +1,107 @@ +// rmfinalepsilon.h + +// 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 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// Copyright 2005-2010 Google, Inc. +// Author: johans@google.com (Johan Schalkwyk) +// +// \file +// Function to remove of final states that have epsilon only input arcs. + +#ifndef FST_LIB_RMFINALEPSILON_H__ +#define FST_LIB_RMFINALEPSILON_H__ + +#include <unordered_set> +using std::tr1::unordered_set; +using std::tr1::unordered_multiset; +#include <vector> +using std::vector; + +#include <fst/connect.h> +#include <fst/mutable-fst.h> + + +namespace fst { + +template<class A> +void RmFinalEpsilon(MutableFst<A>* fst) { + typedef typename A::StateId StateId; + typedef typename A::Weight Weight; + + // Determine the coaccesibility of states. + vector<bool> access; + vector<bool> coaccess; + uint64 props = 0; + SccVisitor<A> scc_visitor(0, &access, &coaccess, &props); + DfsVisit(*fst, &scc_visitor); + + // Find potential list of removable final states. These are final states + // that have no outgoing transitions or final states that have a + // non-coaccessible future. Complexity O(S) + unordered_set<StateId> finals; + for (StateIterator<Fst<A> > siter(*fst); !siter.Done(); siter.Next()) { + StateId s = siter.Value(); + if (fst->Final(s) != Weight::Zero()) { + bool future_coaccess = false; + for (ArcIterator<Fst<A> > aiter(*fst, s); !aiter.Done(); aiter.Next()) { + const A& arc = aiter.Value(); + if (coaccess[arc.nextstate]) { + future_coaccess = true; + break; + } + } + if (!future_coaccess) { + finals.insert(s); + } + } + } + + // Move the final weight. Complexity O(E) + vector<A> arcs; + for (StateIterator<Fst<A> > siter(*fst); !siter.Done(); siter.Next()) { + StateId s = siter.Value(); + Weight w(fst->Final(s)); + + arcs.clear(); + for (ArcIterator<Fst<A> > aiter(*fst, s); !aiter.Done(); aiter.Next()) { + const A& arc = aiter.Value(); + // is next state in the list of finals + if (finals.find(arc.nextstate) != finals.end()) { + // sum up all epsilon arcs + if (arc.ilabel == 0 && arc.olabel == 0) { + w = Plus(Times(fst->Final(arc.nextstate), arc.weight), w); + } else { + arcs.push_back(arc); + } + } else { + arcs.push_back(arc); + } + } + + // If some arcs (epsilon arcs) were deleted, delete all + // arcs and add back only the non epsilon arcs + if (arcs.size() < fst->NumArcs(s)) { + fst->DeleteArcs(s); + fst->SetFinal(s, w); + for (size_t i = 0; i < arcs.size(); ++i) { + fst->AddArc(s, arcs[i]); + } + } + } + + Connect(fst); +} + +} // namespace fst + +#endif // FST_LIB_RMFINALEPSILON_H__ |