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#include "LanguageModelInternal.h"
#include "FactorCollection.h"
#include "NGramNode.h"
#include "InputFileStream.h"
#include "StaticData.h"
using namespace std;
LanguageModelInternal::LanguageModelInternal(bool registerScore, ScoreIndexManager &scoreIndexManager)
:LanguageModelSingleFactor(registerScore, scoreIndexManager)
{
}
bool LanguageModelInternal::Load(const std::string &filePath
, FactorType factorType
, float weight
, size_t nGramOrder)
{
assert(nGramOrder <= 3);
VERBOSE(1, "Loading Internal LM: " << filePath << endl);
FactorCollection &factorCollection = FactorCollection::Instance();
m_filePath = filePath;
m_factorType = factorType;
m_weight = weight;
m_nGramOrder = nGramOrder;
// make sure start & end tags in factor collection
m_sentenceStart = factorCollection.AddFactor(Output, m_factorType, BOS_);
m_sentenceStartArray[m_factorType] = m_sentenceStart;
m_sentenceEnd = factorCollection.AddFactor(Output, m_factorType, EOS_);
m_sentenceEndArray[m_factorType] = m_sentenceEnd;
// read in file
VERBOSE(1, filePath << endl);
InputFileStream inFile(filePath);
// to create lookup vector later on
size_t maxFactorId = 0;
map<size_t, const NGramNode*> lmIdMap;
string line;
int lineNo = 0;
while( !getline(inFile, line, '\n').eof())
{
lineNo++;
if (line.size() != 0 && line.substr(0,1) != "\\")
{
vector<string> tokens = Tokenize(line, "\t");
if (tokens.size() >= 2)
{
// split unigram/bigram trigrams
vector<string> factorStr = Tokenize(tokens[1], " ");
// create / traverse down tree
NGramCollection *ngramColl = &m_map;
NGramNode *nGram;
const Factor *factor;
for (int currFactor = (int) factorStr.size() - 1 ; currFactor >= 0 ; currFactor--)
{
factor = factorCollection.AddFactor(Output, m_factorType, factorStr[currFactor]);
nGram = ngramColl->GetOrCreateNGram(factor);
ngramColl = nGram->GetNGramColl();
}
NGramNode *rootNGram = m_map.GetNGram(factor);
nGram->SetRootNGram(rootNGram);
// create vector of factors used in this LM
size_t factorId = factor->GetId();
maxFactorId = (factorId > maxFactorId) ? factorId : maxFactorId;
lmIdMap[factorId] = rootNGram;
//factorCollection.SetFactorLmId(factor, rootNGram);
float score = TransformSRIScore(Scan<float>(tokens[0]));
nGram->SetScore( score );
if (tokens.size() == 3)
{
float logBackOff = TransformSRIScore(Scan<float>(tokens[2]));
nGram->SetLogBackOff( logBackOff );
}
else
{
nGram->SetLogBackOff( 0 );
}
}
}
}
// add to lookup vector in object
m_lmIdLookup.resize(maxFactorId+1);
fill(m_lmIdLookup.begin(), m_lmIdLookup.end(), static_cast<const NGramNode*>(NULL));
map<size_t, const NGramNode*>::iterator iterMap;
for (iterMap = lmIdMap.begin() ; iterMap != lmIdMap.end() ; ++iterMap)
{
m_lmIdLookup[iterMap->first] = iterMap->second;
}
return true;
}
float LanguageModelInternal::GetValue(const std::vector<const Word*> &contextFactor
, State* finalState
, unsigned int* len) const
{
const size_t ngram = contextFactor.size();
switch (ngram)
{
case 1: return GetValue((*contextFactor[0])[m_factorType], finalState); break;
case 2: return GetValue((*contextFactor[0])[m_factorType]
, (*contextFactor[1])[m_factorType], finalState); break;
case 3: return GetValue((*contextFactor[0])[m_factorType]
, (*contextFactor[1])[m_factorType]
, (*contextFactor[2])[m_factorType], finalState); break;
}
assert (false);
return 0;
}
float LanguageModelInternal::GetValue(const Factor *factor0, State* finalState) const
{
float prob;
const NGramNode *nGram = GetLmID(factor0);
if (nGram == NULL)
{
if (finalState != NULL)
*finalState = NULL;
prob = -numeric_limits<float>::infinity();
}
else
{
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram);
prob = nGram->GetScore();
}
return FloorScore(prob);
}
float LanguageModelInternal::GetValue(const Factor *factor0, const Factor *factor1, State* finalState) const
{
float score;
const NGramNode *nGram[2];
nGram[1] = GetLmID(factor1);
if (nGram[1] == NULL)
{
if (finalState != NULL)
*finalState = NULL;
score = -numeric_limits<float>::infinity();
}
else
{
nGram[0] = nGram[1]->GetNGram(factor0);
if (nGram[0] == NULL)
{ // something unigram
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram[1]);
nGram[0] = GetLmID(factor0);
if (nGram[0] == NULL)
{ // stops at unigram
score = nGram[1]->GetScore();
}
else
{ // unigram unigram
score = nGram[1]->GetScore() + nGram[0]->GetLogBackOff();
}
}
else
{ // bigram
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram[0]);
score = nGram[0]->GetScore();
}
}
return FloorScore(score);
}
float LanguageModelInternal::GetValue(const Factor *factor0, const Factor *factor1, const Factor *factor2, State* finalState) const
{
float score;
const NGramNode *nGram[3];
nGram[2] = GetLmID(factor2);
if (nGram[2] == NULL)
{
if (finalState != NULL)
*finalState = NULL;
score = -numeric_limits<float>::infinity();
}
else
{
nGram[1] = nGram[2]->GetNGram(factor1);
if (nGram[1] == NULL)
{ // something unigram
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram[2]);
nGram[1] = GetLmID(factor1);
if (nGram[1] == NULL)
{ // stops at unigram
score = nGram[2]->GetScore();
}
else
{
nGram[0] = nGram[1]->GetNGram(factor0);
if (nGram[0] == NULL)
{ // unigram unigram
score = nGram[2]->GetScore() + nGram[1]->GetLogBackOff();
}
else
{ // unigram bigram
score = nGram[2]->GetScore() + nGram[1]->GetLogBackOff() + nGram[0]->GetLogBackOff();
}
}
}
else
{ // trigram, or something bigram
nGram[0] = nGram[1]->GetNGram(factor0);
if (nGram[0] != NULL)
{ // trigram
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram[0]);
score = nGram[0]->GetScore();
}
else
{
if (finalState != NULL)
*finalState = static_cast<const void*>(nGram[1]);
score = nGram[1]->GetScore();
nGram[1] = nGram[1]->GetRootNGram();
nGram[0] = nGram[1]->GetNGram(factor0);
if (nGram[0] == NULL)
{ // just bigram
// do nothing
}
else
{
score += nGram[0]->GetLogBackOff();
}
}
// else do nothing. just use 1st bigram
}
}
return FloorScore(score);
}
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