1
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
4 // You may obtain a copy of the License at
5 //
6 // http://www.apache.org/licenses/LICENSE-2.0
7 //
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13 //
14 // Copyright 2005-2010 Google, Inc.
15 // Author: jpr@google.com (Jake Ratkiewicz)
16
17 #ifndef FST_SCRIPT_RMEPSILON_H_
18 #define FST_SCRIPT_RMEPSILON_H_
19
20 #include <vector>
21 using std::vector;
22
23 #include <fst/script/arg-packs.h>
24 #include <fst/script/fst-class.h>
25 #include <fst/script/weight-class.h>
26 #include <fst/script/shortest-distance.h> // for ShortestDistanceOptions
27 #include <fst/rmepsilon.h>
28 #include <fst/queue.h>
29
30 // the following is necessary, or SWIG complains mightily about
31 // shortestdistanceoptions not being defined before being used as a base.
32 #ifdef SWIG
33 %include "nlp/fst/script/shortest-distance.h"
34 #endif
35
36
37 namespace fst {
38 namespace script {
39
40 //
41 // OPTIONS
42 //
43
44 struct RmEpsilonOptions : public fst::script::ShortestDistanceOptions {
45 bool connect;
46 WeightClass weight_threshold;
47 int64 state_threshold;
48
49 RmEpsilonOptions(QueueType qt = AUTO_QUEUE, float d = kDelta, bool c = true,
50 WeightClass w = fst::script::WeightClass::Zero(),
51 int64 n = kNoStateId)
ShortestDistanceOptionsRmEpsilonOptions52 : ShortestDistanceOptions(qt, EPSILON_ARC_FILTER,
53 kNoStateId, d),
54 connect(c), weight_threshold(w), state_threshold(n) { }
55 };
56
57
58 //
59 // TEMPLATES
60 //
61
62 // this function takes care of transforming a script-land RmEpsilonOptions
63 // into a lib-land RmEpsilonOptions
64 template<class Arc>
RmEpsilonHelper(MutableFst<Arc> * fst,vector<typename Arc::Weight> * distance,const RmEpsilonOptions & opts)65 void RmEpsilonHelper(MutableFst<Arc> *fst,
66 vector<typename Arc::Weight> *distance,
67 const RmEpsilonOptions &opts) {
68 typedef typename Arc::StateId StateId;
69 typedef typename Arc::Weight Weight;
70
71 typename Arc::Weight weight_thresh =
72 *(opts.weight_threshold.GetWeight<Weight>());
73
74 switch (opts.queue_type) {
75 case AUTO_QUEUE: {
76 AutoQueue<StateId> queue(*fst, distance, EpsilonArcFilter<Arc>());
77 fst::RmEpsilonOptions<Arc, AutoQueue<StateId> > ropts(
78 &queue, opts.delta, opts.connect, weight_thresh,
79 opts.state_threshold);
80 RmEpsilon(fst, distance, ropts);
81 break;
82 }
83 case FIFO_QUEUE: {
84 FifoQueue<StateId> queue;
85 fst::RmEpsilonOptions<Arc, FifoQueue<StateId> > ropts(
86 &queue, opts.delta, opts.connect, weight_thresh,
87 opts.state_threshold);
88 RmEpsilon(fst, distance, ropts);
89 break;
90 }
91 case LIFO_QUEUE: {
92 LifoQueue<StateId> queue;
93 fst::RmEpsilonOptions<Arc, LifoQueue<StateId> > ropts(
94 &queue, opts.delta, opts.connect, weight_thresh,
95 opts.state_threshold);
96 RmEpsilon(fst, distance, ropts);
97 break;
98 }
99 case SHORTEST_FIRST_QUEUE: {
100 NaturalShortestFirstQueue<StateId, Weight> queue(*distance);
101 fst::RmEpsilonOptions<Arc, NaturalShortestFirstQueue<StateId,
102 Weight> > ropts(
103 &queue, opts.delta, opts.connect, weight_thresh,
104 opts.state_threshold);
105 RmEpsilon(fst, distance, ropts);
106 break;
107 }
108 case STATE_ORDER_QUEUE: {
109 StateOrderQueue<StateId> queue;
110 fst::RmEpsilonOptions<Arc, StateOrderQueue<StateId> > ropts(
111 &queue, opts.delta, opts.connect, weight_thresh,
112 opts.state_threshold);
113 RmEpsilon(fst, distance, ropts);
114 break;
115 }
116 case TOP_ORDER_QUEUE: {
117 TopOrderQueue<StateId> queue(*fst, EpsilonArcFilter<Arc>());
118 fst::RmEpsilonOptions<Arc, TopOrderQueue<StateId> > ropts(
119 &queue, opts.delta, opts.connect, weight_thresh,
120 opts.state_threshold);
121 RmEpsilon(fst, distance, ropts);
122 break;
123 }
124 default:
125 FSTERROR() << "Unknown or unsupported queue type: " << opts.queue_type;
126 fst->SetProperties(kError, kError);
127 }
128 }
129
130 // 1
131 typedef args::Package<const FstClass &, MutableFstClass *,
132 bool, const RmEpsilonOptions &> RmEpsilonArgs1;
133
134 template<class Arc>
RmEpsilon(RmEpsilonArgs1 * args)135 void RmEpsilon(RmEpsilonArgs1 *args) {
136 const Fst<Arc> &ifst = *(args->arg1.GetFst<Arc>());
137 MutableFst<Arc> *ofst = args->arg2->GetMutableFst<Arc>();
138 vector<typename Arc::Weight> distance;
139 bool reverse = args->arg3;
140
141 if (reverse) {
142 VectorFst<Arc> rfst;
143 Reverse(ifst, &rfst);
144 RmEpsilonHelper(&rfst, &distance, args->arg4);
145 Reverse(rfst, ofst);
146 } else {
147 *ofst = ifst;
148 }
149 RmEpsilonHelper(ofst, &distance, args->arg4);
150 }
151
152 // 2
153 typedef args::Package<MutableFstClass *, bool,
154 const WeightClass, int64,
155 float> RmEpsilonArgs2;
156
157 template<class Arc>
RmEpsilon(RmEpsilonArgs2 * args)158 void RmEpsilon(RmEpsilonArgs2 *args) {
159 MutableFst<Arc> *fst = args->arg1->GetMutableFst<Arc>();
160 typename Arc::Weight w = *(args->arg3.GetWeight<typename Arc::Weight>());
161
162 RmEpsilon(fst, args->arg2, w, args->arg4, args->arg5);
163 }
164
165 // 3
166 typedef args::Package<MutableFstClass *, vector<WeightClass> *,
167 const RmEpsilonOptions &> RmEpsilonArgs3;
168
169 template<class Arc>
RmEpsilon(RmEpsilonArgs3 * args)170 void RmEpsilon(RmEpsilonArgs3 *args) {
171 MutableFst<Arc> *fst = args->arg1->GetMutableFst<Arc>();
172 const RmEpsilonOptions &opts = args->arg3;
173
174 vector<typename Arc::Weight> weights;
175
176 RmEpsilonHelper(fst, &weights, opts);
177
178 // Copy the weights back
179 args->arg2->resize(weights.size());
180 for (unsigned i = 0; i < weights.size(); ++i) {
181 (*args->arg2)[i] = WeightClass(weights[i]);
182 }
183 }
184
185 //
186 // PROTOTYPES
187 //
188
189 // 1
190 void RmEpsilon(const FstClass &ifst, MutableFstClass *ofst,
191 bool reverse = false,
192 const RmEpsilonOptions& opts =
193 fst::script::RmEpsilonOptions());
194
195 // 2
196 void RmEpsilon(MutableFstClass *arc, bool connect = true,
197 const WeightClass &weight_threshold =
198 fst::script::WeightClass::Zero(),
199 int64 state_threshold = fst::kNoStateId,
200 float delta = fst::kDelta);
201
202 // 3
203 void RmEpsilon(MutableFstClass *fst, vector<WeightClass> *distance,
204 const RmEpsilonOptions &opts);
205
206
207 } // namespace script
208 } // namespace fst
209
210
211 #endif // FST_SCRIPT_RMEPSILON_H_
212