mosesdecoder/moses/TargetWordInsertionFeature.cpp

128 lines
3.5 KiB
C++

#include <sstream>
#include "TargetWordInsertionFeature.h"
#include "Phrase.h"
#include "TargetPhrase.h"
#include "Hypothesis.h"
#include "ChartHypothesis.h"
#include "ScoreComponentCollection.h"
#include "TranslationOption.h"
#include "UserMessage.h"
namespace Moses {
using namespace std;
TargetWordInsertionFeature::TargetWordInsertionFeature(const std::string &line)
:StatelessFeatureFunction("twi", ScoreProducer::unlimited, line),
m_unrestricted(true)
{
std::cerr << "Initializing target word insertion feature.." << std::endl;
string filename;
for (size_t i = 0; i < m_args.size(); ++i) {
const vector<string> &args = m_args[i];
if (args[0] == "factor") {
m_factorType = Scan<FactorType>(args[1]);
}
else if (args[0] == "path") {
filename = args[1];
}
}
// load word list for restricted feature set
if (filename != "") {
cerr << "loading target word insertion word list from " << filename << endl;
if (!Load(filename)) {
UserMessage::Add("Unable to load word list for target word insertion feature from file " + filename);
//return false;
}
}
}
bool TargetWordInsertionFeature::Load(const std::string &filePath)
{
ifstream inFile(filePath.c_str());
if (!inFile)
{
cerr << "could not open file " << filePath << endl;
return false;
}
std::string line;
while (getline(inFile, line)) {
m_vocab.insert(line);
}
inFile.close();
m_unrestricted = false;
return true;
}
void TargetWordInsertionFeature::Evaluate(
const PhraseBasedFeatureContext& context,
ScoreComponentCollection* accumulator) const
{
const TargetPhrase& targetPhrase = context.GetTargetPhrase();
const AlignmentInfo &alignmentInfo = targetPhrase.GetAlignTerm();
ComputeFeatures(targetPhrase, accumulator, alignmentInfo);
}
void TargetWordInsertionFeature::EvaluateChart(
const ChartBasedFeatureContext& context,
ScoreComponentCollection* accumulator) const
{
const TargetPhrase& targetPhrase = context.GetTargetPhrase();
const AlignmentInfo &alignmentInfo = context.GetTargetPhrase().GetAlignTerm();
ComputeFeatures(targetPhrase, accumulator, alignmentInfo);
}
void TargetWordInsertionFeature::ComputeFeatures(const TargetPhrase& targetPhrase,
ScoreComponentCollection* accumulator,
const AlignmentInfo &alignmentInfo) const
{
// handle special case: unknown words (they have no word alignment)
size_t targetLength = targetPhrase.GetSize();
size_t sourceLength = targetPhrase.GetSourcePhrase().GetSize();
if (targetLength == 1 && sourceLength == 1) {
const Factor* f1 = targetPhrase.GetWord(0).GetFactor(1);
if (f1 && f1->GetString().compare(UNKNOWN_FACTOR) == 0) {
return;
}
}
// flag aligned words
bool aligned[16];
CHECK(targetLength < 16);
for(size_t i=0; i<targetLength; i++) {
aligned[i] = false;
}
for (AlignmentInfo::const_iterator alignmentPoint = alignmentInfo.begin(); alignmentPoint != alignmentInfo.end(); alignmentPoint++) {
aligned[ alignmentPoint->second ] = true;
}
// process unaligned target words
for(size_t i=0; i<targetLength; i++) {
if (!aligned[i]) {
Word w = targetPhrase.GetWord(i);
if (!w.IsNonTerminal()) {
const string &word = w.GetFactor(m_factorType)->GetString();
if (word != "<s>" && word != "</s>") {
if (!m_unrestricted && m_vocab.find( word ) == m_vocab.end()) {
accumulator->PlusEquals(this,"OTHER",1);
}
else {
accumulator->PlusEquals(this,word,1);
}
}
}
}
}
}
}