mosesdecoder/moses/FF/GlobalLexicalModel.cpp
2013-06-20 13:25:02 +01:00

191 lines
6.3 KiB
C++

#include <fstream>
#include "GlobalLexicalModel.h"
#include "moses/StaticData.h"
#include "moses/InputFileStream.h"
#include "moses/TranslationOption.h"
#include "moses/UserMessage.h"
using namespace std;
namespace Moses
{
GlobalLexicalModel::GlobalLexicalModel(const std::string &line)
: StatelessFeatureFunction("GlobalLexicalModel",1, line)
{
std::cerr << "Creating global lexical model...\n";
ReadParameters();
// define bias word
FactorCollection &factorCollection = FactorCollection::Instance();
m_bias = new Word();
const Factor* factor = factorCollection.AddFactor( Input, m_inputFactorsVec[0], "**BIAS**" );
m_bias->SetFactor( m_inputFactorsVec[0], factor );
}
void GlobalLexicalModel::SetParameter(const std::string& key, const std::string& value)
{
if (key == "file") {
m_filePath = value;
} else if (key == "inputFactors") {
m_inputFactorsVec = Tokenize<FactorType>(value,",");
} else if (key == "outputFactors") {
m_outputFactorsVec = Tokenize<FactorType>(value,",");
} else {
StatelessFeatureFunction::SetParameter(key, value);
}
}
GlobalLexicalModel::~GlobalLexicalModel()
{
// delete words in the hash data structure
DoubleHash::const_iterator iter;
for(iter = m_hash.begin(); iter != m_hash.end(); iter++ ) {
map< const Word*, float, WordComparer >::const_iterator iter2;
for(iter2 = iter->second.begin(); iter2 != iter->second.end(); iter2++ ) {
delete iter2->first; // delete input word
}
delete iter->first; // delete output word
}
}
void GlobalLexicalModel::Load()
{
FactorCollection &factorCollection = FactorCollection::Instance();
const std::string& factorDelimiter = StaticData::Instance().GetFactorDelimiter();
VERBOSE(2, "Loading global lexical model from file " << m_filePath << endl);
m_inputFactors = FactorMask(m_inputFactorsVec);
m_outputFactors = FactorMask(m_outputFactorsVec);
InputFileStream inFile(m_filePath);
// reading in data one line at a time
size_t lineNum = 0;
string line;
while(getline(inFile, line)) {
++lineNum;
vector<string> token = Tokenize<string>(line, " ");
if (token.size() != 3) { // format checking
stringstream errorMessage;
errorMessage << "Syntax error at " << m_filePath << ":" << lineNum << endl << line << endl;
UserMessage::Add(errorMessage.str());
abort();
}
// create the output word
Word *outWord = new Word();
vector<string> factorString = Tokenize( token[0], factorDelimiter );
for (size_t i=0 ; i < m_outputFactorsVec.size() ; i++) {
const FactorDirection& direction = Output;
const FactorType& factorType = m_outputFactorsVec[i];
const Factor* factor = factorCollection.AddFactor( direction, factorType, factorString[i] );
outWord->SetFactor( factorType, factor );
}
// create the input word
Word *inWord = new Word();
factorString = Tokenize( token[1], factorDelimiter );
for (size_t i=0 ; i < m_inputFactorsVec.size() ; i++) {
const FactorDirection& direction = Input;
const FactorType& factorType = m_inputFactorsVec[i];
const Factor* factor = factorCollection.AddFactor( direction, factorType, factorString[i] );
inWord->SetFactor( factorType, factor );
}
// maximum entropy feature score
float score = Scan<float>(token[2]);
// std::cerr << "storing word " << *outWord << " " << *inWord << " " << score << endl;
// store feature in hash
DoubleHash::iterator keyOutWord = m_hash.find( outWord );
if( keyOutWord == m_hash.end() ) {
m_hash[outWord][inWord] = score;
} else { // already have hash for outword, delete the word to avoid leaks
(keyOutWord->second)[inWord] = score;
delete outWord;
}
}
}
void GlobalLexicalModel::InitializeForInput( Sentence const& in )
{
m_local.reset(new ThreadLocalStorage);
m_local->input = &in;
}
float GlobalLexicalModel::ScorePhrase( const TargetPhrase& targetPhrase ) const
{
const Sentence& input = *(m_local->input);
float score = 0;
for(size_t targetIndex = 0; targetIndex < targetPhrase.GetSize(); targetIndex++ ) {
float sum = 0;
const Word& targetWord = targetPhrase.GetWord( targetIndex );
VERBOSE(2,"glm " << targetWord << ": ");
const DoubleHash::const_iterator targetWordHash = m_hash.find( &targetWord );
if( targetWordHash != m_hash.end() ) {
SingleHash::const_iterator inputWordHash = targetWordHash->second.find( m_bias );
if( inputWordHash != targetWordHash->second.end() ) {
VERBOSE(2,"*BIAS* " << inputWordHash->second);
sum += inputWordHash->second;
}
set< const Word*, WordComparer > alreadyScored; // do not score a word twice
for(size_t inputIndex = 0; inputIndex < input.GetSize(); inputIndex++ ) {
const Word& inputWord = input.GetWord( inputIndex );
if ( alreadyScored.find( &inputWord ) == alreadyScored.end() ) {
SingleHash::const_iterator inputWordHash = targetWordHash->second.find( &inputWord );
if( inputWordHash != targetWordHash->second.end() ) {
VERBOSE(2," " << inputWord << " " << inputWordHash->second);
sum += inputWordHash->second;
}
alreadyScored.insert( &inputWord );
}
}
}
// Hal Daume says: 1/( 1 + exp [ - sum_i w_i * f_i ] )
VERBOSE(2," p=" << FloorScore( log(1/(1+exp(-sum))) ) << endl);
score += FloorScore( log(1/(1+exp(-sum))) );
}
return score;
}
float GlobalLexicalModel::GetFromCacheOrScorePhrase( const TargetPhrase& targetPhrase ) const
{
LexiconCache& m_cache = m_local->cache;
const LexiconCache::const_iterator query = m_cache.find( &targetPhrase );
if ( query != m_cache.end() ) {
return query->second;
}
float score = ScorePhrase( targetPhrase );
m_cache.insert( pair<const TargetPhrase*, float>(&targetPhrase, score) );
//VERBOSE(2, "add to cache " << targetPhrase << ": " << score << endl);
return score;
}
void GlobalLexicalModel::Evaluate
(const PhraseBasedFeatureContext& context,
ScoreComponentCollection* accumulator) const
{
accumulator->PlusEquals( this,
GetFromCacheOrScorePhrase(context.GetTargetPhrase()) );
}
bool GlobalLexicalModel::IsUseable(const FactorMask &mask) const
{
for (size_t i = 0; i < m_outputFactors.size(); ++i) {
if (m_outputFactors[i]) {
if (!mask[i]) {
return false;
}
}
}
return true;
}
}