From 96a32415ab43377cf1575bd3f4f2980f58028209 Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Fri, 14 Aug 2015 11:51:42 +0800
Subject: add implementation for kaldi io (by ymz)

---
 .../src/tools/openfst/include/fst/epsnormalize.h   | 73 ++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 kaldi_io/src/tools/openfst/include/fst/epsnormalize.h

(limited to 'kaldi_io/src/tools/openfst/include/fst/epsnormalize.h')

diff --git a/kaldi_io/src/tools/openfst/include/fst/epsnormalize.h b/kaldi_io/src/tools/openfst/include/fst/epsnormalize.h
new file mode 100644
index 0000000..9d178b1
--- /dev/null
+++ b/kaldi_io/src/tools/openfst/include/fst/epsnormalize.h
@@ -0,0 +1,73 @@
+// epsnormalize.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: allauzen@google.com (Cyril Allauzen)
+//
+// \file
+// Function that implements epsilon normalization.
+
+#ifndef FST_LIB_EPSNORMALIZE_H__
+#define FST_LIB_EPSNORMALIZE_H__
+
+#include <tr1/unordered_map>
+using std::tr1::unordered_map;
+using std::tr1::unordered_multimap;
+
+
+#include <fst/factor-weight.h>
+#include <fst/invert.h>
+#include <fst/arc-map.h>
+#include <fst/rmepsilon.h>
+
+
+namespace fst {
+
+enum EpsNormalizeType {EPS_NORM_INPUT, EPS_NORM_OUTPUT};
+
+// Returns an equivalent FST that is epsilon-normalized. An acceptor is
+// epsilon-normalized if it is epsilon-removed. A transducer is input
+// epsilon-normalized if additionally if on each path any epsilon input
+// label follows all non-epsilon input labels. Output epsilon-normalized
+// is defined similarly.
+//
+// The input FST needs to be functional.
+//
+// References:
+// - Mehryar Mohri. "Generic epsilon-removal and input epsilon-normalization
+//   algorithms for weighted transducers", International Journal of Computer
+//   Science, 13(1): 129-143, 2002.
+template <class Arc>
+void EpsNormalize(const Fst<Arc> &ifst, MutableFst<Arc> *ofst,
+                      EpsNormalizeType type = EPS_NORM_INPUT) {
+  VectorFst< GallicArc<Arc, STRING_RIGHT_RESTRICT> > gfst;
+  if (type == EPS_NORM_INPUT)
+    ArcMap(ifst, &gfst, ToGallicMapper<Arc, STRING_RIGHT_RESTRICT>());
+  else // type == EPS_NORM_OUTPUT
+    ArcMap(InvertFst<Arc>(ifst), &gfst,
+           ToGallicMapper<Arc, STRING_RIGHT_RESTRICT>());
+  RmEpsilon(&gfst);
+  FactorWeightFst< GallicArc<Arc, STRING_RIGHT_RESTRICT>,
+    GallicFactor<typename Arc::Label,
+      typename Arc::Weight, STRING_RIGHT_RESTRICT> >
+    fwfst(gfst);
+  ArcMap(fwfst, ofst, FromGallicMapper<Arc, STRING_RIGHT_RESTRICT>());
+  ofst->SetOutputSymbols(ifst.OutputSymbols());
+  if(type == EPS_NORM_OUTPUT)
+    Invert(ofst);
+}
+
+}  // namespace fst
+
+#endif  // FST_LIB_EPSNORMALIZE_H__
-- 
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