mirror of
https://github.com/moses-smt/mosesdecoder.git
synced 2024-09-20 07:42:21 +03:00
5240c430ce
This adds a new string-to-tree decoder, which can be enabled with the -s2t option. It's intended to be faster and simpler than the generic chart decoder, and is designed to support lattice input (still WIP). For a en-de system trained on WMT14 data, it's approximately 40% faster in practice. For background information, see the decoding section of the EMNLP tutorial on syntax-based MT: http://www.emnlp2014.org/tutorials/5_notes.pdf Some features are not implemented yet, including support for internal tree structure and soft source-syntactic constraints.
60 lines
1.8 KiB
C++
60 lines
1.8 KiB
C++
#include "SHyperedge.h"
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#include "moses/StaticData.h"
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#include "SVertex.h"
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namespace Moses
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{
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namespace Syntax
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{
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Phrase GetOneBestTargetYield(const SHyperedge &h)
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{
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FactorType placeholderFactor = StaticData::Instance().GetPlaceholderFactor();
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Phrase ret(ARRAY_SIZE_INCR);
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const AlignmentInfo::NonTermIndexMap &targetToSourceMap =
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h.translation->GetAlignNonTerm().GetNonTermIndexMap2();
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for (std::size_t pos = 0; pos < h.translation->GetSize(); ++pos) {
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const Word &word = h.translation->GetWord(pos);
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if (word.IsNonTerminal()) {
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std::size_t sourceIndex = targetToSourceMap[pos];
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const SHyperedge &incoming = *h.tail[sourceIndex]->best;
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Phrase subPhrase = GetOneBestTargetYield(incoming);
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ret.Append(subPhrase);
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} else {
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ret.AddWord(word);
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if (placeholderFactor == NOT_FOUND) {
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continue;
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}
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assert(false);
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// FIXME Modify this chunk of code to work for SHyperedge.
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/*
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std::set<std::size_t> sourcePosSet =
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h.translation->GetAlignTerm().GetAlignmentsForTarget(pos);
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if (sourcePosSet.size() == 1) {
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const std::vector<const Word*> *ruleSourceFromInputPath =
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hypo.GetTranslationOption().GetSourceRuleFromInputPath();
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UTIL_THROW_IF2(ruleSourceFromInputPath == NULL,
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"Source Words in of the rules hasn't been filled out");
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std::size_t sourcePos = *sourcePosSet.begin();
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const Word *sourceWord = ruleSourceFromInputPath->at(sourcePos);
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UTIL_THROW_IF2(sourceWord == NULL,
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"Null source word at position " << sourcePos);
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const Factor *factor = sourceWord->GetFactor(placeholderFactor);
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if (factor) {
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ret.Back()[0] = factor;
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}
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}
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*/
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}
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}
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return ret;
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}
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} // Syntax
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} // Moses
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