1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
|
// $Id$
// vim:tabstop=2
/***********************************************************************
Moses - factored phrase-based language decoder
Copyright (C) 2010 Hieu Hoang
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
***********************************************************************/
#include <stdio.h>
#include "ChartManager.h"
#include "ChartCell.h"
#include "ChartHypothesis.h"
#include "ChartTranslationOptions.h"
#include "ChartTrellisDetourQueue.h"
#include "ChartTrellisNode.h"
#include "ChartTrellisPath.h"
#include "ChartTrellisPathList.h"
#include "StaticData.h"
#include "DecodeStep.h"
#include "TreeInput.h"
#include "moses/FF/WordPenaltyProducer.h"
using namespace std;
using namespace Moses;
namespace Moses
{
extern bool g_debug;
/* constructor. Initialize everything prior to decoding a particular sentence.
* \param source the sentence to be decoded
* \param system which particular set of models to use.
*/
ChartManager::ChartManager(InputType const& source)
:m_source(source)
,m_hypoStackColl(source, *this)
,m_start(clock())
,m_hypothesisId(0)
,m_parser(source, m_hypoStackColl)
,m_translationOptionList(StaticData::Instance().GetRuleLimit())
{
}
ChartManager::~ChartManager()
{
clock_t end = clock();
float et = (end - m_start);
et /= (float)CLOCKS_PER_SEC;
VERBOSE(1, "Translation took " << et << " seconds" << endl);
}
//! decode the sentence. This contains the main laps. Basically, the CKY++ algorithm
void ChartManager::ProcessSentence()
{
VERBOSE(1,"Translating: " << m_source << endl);
ResetSentenceStats(m_source);
VERBOSE(2,"Decoding: " << endl);
//ChartHypothesis::ResetHypoCount();
AddXmlChartOptions();
// MAIN LOOP
size_t size = m_source.GetSize();
for (size_t width = 1; width <= size; ++width) {
for (size_t startPos = 0; startPos <= size-width; ++startPos) {
size_t endPos = startPos + width - 1;
WordsRange range(startPos, endPos);
// create trans opt
m_translationOptionList.Clear();
m_parser.Create(range, m_translationOptionList);
m_translationOptionList.ApplyThreshold();
PreCalculateScores();
// decode
ChartCell &cell = m_hypoStackColl.Get(range);
cell.ProcessSentence(m_translationOptionList, m_hypoStackColl);
m_translationOptionList.Clear();
cell.PruneToSize();
cell.CleanupArcList();
cell.SortHypotheses();
}
}
IFVERBOSE(1) {
for (size_t startPos = 0; startPos < size; ++startPos) {
cerr.width(3);
cerr << startPos << " ";
}
cerr << endl;
for (size_t width = 1; width <= size; width++) {
for( size_t space = 0; space < width-1; space++ ) {
cerr << " ";
}
for (size_t startPos = 0; startPos <= size-width; ++startPos) {
WordsRange range(startPos, startPos+width-1);
cerr.width(3);
cerr << m_hypoStackColl.Get(range).GetSize() << " ";
}
cerr << endl;
}
}
}
/** add specific translation options and hypotheses according to the XML override translation scheme.
* Doesn't seem to do anything about walls and zones.
* @todo check walls & zones. Check that the implementation doesn't leak, xml options sometimes does if you're not careful
*/
void ChartManager::AddXmlChartOptions()
{
const StaticData &staticData = StaticData::Instance();
const std::vector <ChartTranslationOptions*> xmlChartOptionsList = m_source.GetXmlChartTranslationOptions();
IFVERBOSE(2) {
cerr << "AddXmlChartOptions " << xmlChartOptionsList.size() << endl;
}
if (xmlChartOptionsList.size() == 0) return;
for(std::vector<ChartTranslationOptions*>::const_iterator i = xmlChartOptionsList.begin();
i != xmlChartOptionsList.end(); ++i) {
ChartTranslationOptions* opt = *i;
TargetPhrase &targetPhrase = *opt->GetTargetPhraseCollection().GetCollection()[0];
targetPhrase.GetScoreBreakdown().Assign(staticData.GetWordPenaltyProducer(), -1);
const WordsRange &range = opt->GetSourceWordsRange();
RuleCubeItem* item = new RuleCubeItem( *opt, m_hypoStackColl );
ChartHypothesis* hypo = new ChartHypothesis(*opt, *item, *this);
hypo->CalcScore();
ChartCell &cell = m_hypoStackColl.Get(range);
cell.AddHypothesis(hypo);
}
}
//! get best complete translation from the top chart cell.
const ChartHypothesis *ChartManager::GetBestHypothesis() const
{
size_t size = m_source.GetSize();
if (size == 0) // empty source
return NULL;
else {
WordsRange range(0, size-1);
const ChartCell &lastCell = m_hypoStackColl.Get(range);
return lastCell.GetBestHypothesis();
}
}
/** Calculate the n-best paths through the output hypergraph.
* Return the list of paths with the variable ret
* \param count how may paths to return
* \param ret return argument
* \param onlyDistinct whether to check for distinct output sentence or not (default - don't check, just return top n-paths)
*/
void ChartManager::CalcNBest(size_t count, ChartTrellisPathList &ret,bool onlyDistinct) const
{
size_t size = m_source.GetSize();
if (count == 0 || size == 0)
return;
// Build a ChartTrellisPath for the 1-best path, if any.
WordsRange range(0, size-1);
const ChartCell &lastCell = m_hypoStackColl.Get(range);
const ChartHypothesis *hypo = lastCell.GetBestHypothesis();
if (hypo == NULL) {
// no hypothesis
return;
}
boost::shared_ptr<ChartTrellisPath> basePath(new ChartTrellisPath(*hypo));
// Add it to the n-best list.
if (count == 1) {
ret.Add(basePath);
return;
}
// Set a limit on the number of detours to pop. If the n-best list is
// restricted to distinct translations then this limit should be bigger
// than n. The n-best factor determines how much bigger the limit should be.
const StaticData &staticData = StaticData::Instance();
const size_t nBestFactor = staticData.GetNBestFactor();
size_t popLimit;
if (!onlyDistinct) {
popLimit = count-1;
} else if (nBestFactor == 0) {
// 0 = 'unlimited.' This actually sets a large-ish limit in case too many
// translations are identical.
popLimit = count * 1000;
} else {
popLimit = count * nBestFactor;
}
// Create an empty priority queue of detour objects. It is bounded to
// contain no more than popLimit items.
ChartTrellisDetourQueue contenders(popLimit);
// Get all complete translations
const HypoList *topHypos = lastCell.GetAllSortedHypotheses();
// Create a ChartTrellisDetour for each complete translation and add it to the queue
HypoList::const_iterator iter;
for (iter = topHypos->begin(); iter != topHypos->end(); ++iter) {
const ChartHypothesis &hypo = **iter;
boost::shared_ptr<ChartTrellisPath> basePath(new ChartTrellisPath(hypo));
ChartTrellisDetour *detour = new ChartTrellisDetour(basePath, basePath->GetFinalNode(), hypo);
contenders.Push(detour);
}
delete topHypos;
// Record the output phrase if distinct translations are required.
set<Phrase> distinctHyps;
// MAIN loop
for (size_t i = 0; ret.GetSize() < count && !contenders.Empty() && i < popLimit; ++i) {
// Get the best detour from the queue.
std::auto_ptr<const ChartTrellisDetour> detour(contenders.Pop());
CHECK(detour.get());
// Create a full base path from the chosen detour.
//basePath.reset(new ChartTrellisPath(*detour));
boost::shared_ptr<ChartTrellisPath> path(new ChartTrellisPath(*detour));
// Generate new detours from this base path and add them to the queue of
// contenders. The new detours deviate from the base path by a single
// replacement along the previous detour sub-path.
CHECK(path->GetDeviationPoint());
CreateDeviantPaths(path, *(path->GetDeviationPoint()), contenders);
// If the n-best list is allowed to contain duplicate translations (at the
// surface level) then add the new path unconditionally, otherwise check
// whether the translation has seen before.
if (!onlyDistinct) {
ret.Add(path);
} else {
Phrase tgtPhrase = path->GetOutputPhrase();
if (distinctHyps.insert(tgtPhrase).second) {
ret.Add(path);
}
}
}
}
void ChartManager::GetSearchGraph(long translationId, std::ostream &outputSearchGraphStream) const
{
size_t size = m_source.GetSize();
// which hypotheses are reachable?
std::map<unsigned,bool> reachable;
WordsRange fullRange(0, size-1);
const ChartCell &lastCell = m_hypoStackColl.Get(fullRange);
const ChartHypothesis *hypo = lastCell.GetBestHypothesis();
if (hypo == NULL) {
// no hypothesis
return;
}
FindReachableHypotheses( hypo, reachable);
for (size_t width = 1; width <= size; ++width) {
for (size_t startPos = 0; startPos <= size-width; ++startPos) {
size_t endPos = startPos + width - 1;
WordsRange range(startPos, endPos);
TRACE_ERR(" " << range << "=");
const ChartCell &cell = m_hypoStackColl.Get(range);
cell.GetSearchGraph(translationId, outputSearchGraphStream, reachable);
}
}
}
void ChartManager::FindReachableHypotheses( const ChartHypothesis *hypo, std::map<unsigned,bool> &reachable ) const
{
// do not recurse, if already visited
if (reachable.find(hypo->GetId()) != reachable.end()) {
return;
}
// recurse
reachable[ hypo->GetId() ] = true;
const std::vector<const ChartHypothesis*> &previous = hypo->GetPrevHypos();
for(std::vector<const ChartHypothesis*>::const_iterator i = previous.begin(); i != previous.end(); ++i) {
FindReachableHypotheses( *i, reachable );
}
// also loop over recombined hypotheses (arcs)
const ChartArcList *arcList = hypo->GetArcList();
if (arcList) {
ChartArcList::const_iterator iterArc;
for (iterArc = arcList->begin(); iterArc != arcList->end(); ++iterArc) {
const ChartHypothesis &arc = **iterArc;
FindReachableHypotheses( &arc, reachable );
}
}
}
void ChartManager::CreateDeviantPaths(
boost::shared_ptr<const ChartTrellisPath> basePath,
ChartTrellisDetourQueue &q)
{
CreateDeviantPaths(basePath, basePath->GetFinalNode(), q);
}
void ChartManager::CreateDeviantPaths(
boost::shared_ptr<const ChartTrellisPath> basePath,
const ChartTrellisNode &substitutedNode,
ChartTrellisDetourQueue &queue)
{
const ChartArcList *arcList = substitutedNode.GetHypothesis().GetArcList();
if (arcList) {
for (ChartArcList::const_iterator iter = arcList->begin();
iter != arcList->end(); ++iter) {
const ChartHypothesis &replacement = **iter;
queue.Push(new ChartTrellisDetour(basePath, substitutedNode,
replacement));
}
}
// recusively create deviant paths for child nodes
const ChartTrellisNode::NodeChildren &children = substitutedNode.GetChildren();
ChartTrellisNode::NodeChildren::const_iterator iter;
for (iter = children.begin(); iter != children.end(); ++iter) {
const ChartTrellisNode &child = **iter;
CreateDeviantPaths(basePath, child, queue);
}
}
void ChartManager::PreCalculateScores()
{
const StaticData &staticData = StaticData::Instance();
for (size_t i = 0; i < m_translationOptionList.GetSize(); ++i) {
const ChartTranslationOptions& cto = m_translationOptionList.Get(i);
for (TargetPhraseCollection::const_iterator j = cto.GetTargetPhraseCollection().begin();
j != cto.GetTargetPhraseCollection().end(); ++j) {
const TargetPhrase* targetPhrase = *j;
if (m_precalculatedScores.find(*targetPhrase) == m_precalculatedScores.end()) {
ChartBasedFeatureContext context(*targetPhrase,m_source);
const vector<const StatelessFeatureFunction*>& sfs =
StatelessFeatureFunction::GetStatelessFeatureFunctions();
ScoreComponentCollection& breakdown = m_precalculatedScores[*targetPhrase];
for (size_t k = 0; k < sfs.size(); ++k) {
if (! staticData.IsFeatureFunctionIgnored( *sfs[k] )) {
sfs[k]->EvaluateChart(context,&breakdown);
}
}
}
}
}
}
void ChartManager::InsertPreCalculatedScores(
const TargetPhrase& targetPhrase, ScoreComponentCollection* scoreBreakdown) const
{
boost::unordered_map<TargetPhrase,ScoreComponentCollection>::const_iterator scoreIter =
m_precalculatedScores.find(targetPhrase);
if (scoreIter != m_precalculatedScores.end()) {
scoreBreakdown->PlusEquals(scoreIter->second);
} else {
TRACE_ERR("ERROR: " << targetPhrase << " missing from precalculation cache" << endl);
assert(0);
}
}
} // namespace Moses
|