mosesdecoder/mira/MiraOptimiser.cpp
2011-08-18 12:59:38 +02:00

325 lines
13 KiB
C++

#include "Optimiser.h"
#include "Hildreth.h"
#include "StaticData.h"
using namespace Moses;
using namespace std;
namespace Mira {
size_t MiraOptimiser::updateWeights(ScoreComponentCollection& currWeights,
const vector<vector<ScoreComponentCollection> >& featureValues,
const vector<vector<float> >& losses,
const vector<vector<float> >& bleuScores,
const vector<ScoreComponentCollection>& oracleFeatureValues,
const vector<float> oracleBleuScores,
const vector<size_t> sentenceIds,
float learning_rate,
size_t rank,
size_t epoch) {
// vector of feature values differences for all created constraints
vector<ScoreComponentCollection> featureValueDiffs;
vector<float> lossMinusModelScoreDiffs;
vector<float> all_losses;
// most violated constraint in batch
ScoreComponentCollection max_batch_featureValueDiff;
float max_batch_lossMinusModelScoreDiff = -1;
// Make constraints for new hypothesis translations
float epsilon = 0.0001;
int violatedConstraintsBefore = 0;
float oldDistanceFromOptimum = 0;
// iterate over input sentences (1 (online) or more (batch))
for (size_t i = 0; i < featureValues.size(); ++i) {
//size_t sentenceId = sentenceIds[i];
// iterate over hypothesis translations for one input sentence
for (size_t j = 0; j < featureValues[i].size(); ++j) {
ScoreComponentCollection featureValueDiff = oracleFeatureValues[i];
featureValueDiff.MinusEquals(featureValues[i][j]);
cerr << "Rank " << rank << ", epoch " << epoch << ", feature value diff: " << featureValueDiff << endl;
if (featureValueDiff.GetL1Norm() == 0) {
// skip constraint
continue;
}
float loss = losses[i][j];
if (m_scale_margin == 1) {
loss *= oracleBleuScores[i];
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with oracle bleu score " << oracleBleuScores[i] << endl;
}
else if (m_scale_margin == 2) {
loss *= log2(oracleBleuScores[i]);
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with log2 oracle bleu score " << log2(oracleBleuScores[i]) << endl;
}
else if (m_scale_margin == 10) {
loss *= log10(oracleBleuScores[i]);
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with log10 oracle bleu score " << log10(oracleBleuScores[i]) << endl;
}
// check if constraint is violated
bool violated = false;
bool addConstraint = true;
float modelScoreDiff = featureValueDiff.InnerProduct(currWeights);
float diff = 0;
if (loss > (modelScoreDiff + m_margin_slack)) {
diff = loss - (modelScoreDiff + m_margin_slack);
}
cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " + " << m_margin_slack << " >= " << loss << " (current violation: " << diff << ")" << endl;
if (diff > epsilon) {
violated = true;
}
else if (m_onlyViolatedConstraints) {
addConstraint = false;
}
float lossMinusModelScoreDiff = loss - modelScoreDiff;
if (addConstraint) {
featureValueDiffs.push_back(featureValueDiff);
lossMinusModelScoreDiffs.push_back(lossMinusModelScoreDiff);
all_losses.push_back(loss);
if (violated) {
++violatedConstraintsBefore;
oldDistanceFromOptimum += diff;
}
}
}
}
// run optimisation: compute alphas for all given constraints
vector<float> alphas;
ScoreComponentCollection summedUpdate;
if (violatedConstraintsBefore > 0) {
cerr << "Rank " << rank << ", epoch " << epoch << ", number of constraints passed to optimizer: " <<
featureValueDiffs.size() << " (of which violated: " << violatedConstraintsBefore << ")" << endl;
if (m_slack != 0) {
alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs, m_slack);
} else {
alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs);
}
// Update the weight vector according to the alphas and the feature value differences
// * w' = w' + SUM alpha_i * (h_i(oracle) - h_i(hypothesis))
for (size_t k = 0; k < featureValueDiffs.size(); ++k) {
float alpha = alphas[k];
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", alpha: " << alpha << endl);
ScoreComponentCollection update(featureValueDiffs[k]);
update.MultiplyEquals(alpha);
// sum updates
summedUpdate.PlusEquals(update);
}
}
else {
cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
return 0;
}
// apply learning rate
if (learning_rate != 1) {
cerr << "Rank " << rank << ", epoch " << epoch << ", apply learning rate " << learning_rate << " to update." << endl;
summedUpdate.MultiplyEquals(learning_rate);
}
// scale update by BLEU of oracle (for batch size 1 only)
if (oracleBleuScores.size() == 1) {
if (m_scale_update == 1) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with oracle bleu score " << oracleBleuScores[0] << endl;
summedUpdate.MultiplyEquals(oracleBleuScores[0]);
}
else if (m_scale_update == 2) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with log2 oracle bleu score " << log2(oracleBleuScores[0]) << endl;
summedUpdate.MultiplyEquals(log2(oracleBleuScores[0]));
}
else if (m_scale_update == 10) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with log10 oracle bleu score " << log10(oracleBleuScores[0]) << endl;
summedUpdate.MultiplyEquals(log10(oracleBleuScores[0]));
}
}
cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << summedUpdate << endl;
// apply update to weight vector
currWeights.PlusEquals(summedUpdate);
// Sanity check: are there still violated constraints after optimisation?
int violatedConstraintsAfter = 0;
float newDistanceFromOptimum = 0;
for (size_t i = 0; i < featureValueDiffs.size(); ++i) {
float modelScoreDiff = featureValueDiffs[i].InnerProduct(currWeights);
float loss = all_losses[i];
float diff = loss - (modelScoreDiff + m_margin_slack);
if (diff > epsilon) {
++violatedConstraintsAfter;
newDistanceFromOptimum += diff;
}
}
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", violated constraint before: " << violatedConstraintsBefore << ", after: " << violatedConstraintsAfter << ", change: " << violatedConstraintsBefore - violatedConstraintsAfter << endl);
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", error before: " << oldDistanceFromOptimum << ", after: " << newDistanceFromOptimum << ", change: " << oldDistanceFromOptimum - newDistanceFromOptimum << endl);
return violatedConstraintsAfter;
}
size_t MiraOptimiser::updateWeightsHopeFear(Moses::ScoreComponentCollection& currWeights,
const std::vector< std::vector<Moses::ScoreComponentCollection> >& featureValuesHope,
const std::vector< std::vector<Moses::ScoreComponentCollection> >& featureValuesFear,
const std::vector<std::vector<float> >& bleuScoresHope,
const std::vector<std::vector<float> >& bleuScoresFear,
const std::vector< size_t> sentenceIds,
float learning_rate,
size_t rank,
size_t epoch) {
// vector of feature values differences for all created constraints
vector<ScoreComponentCollection> featureValueDiffs;
vector<float> lossMinusModelScoreDiffs;
vector<float> all_losses;
// most violated constraint in batch
ScoreComponentCollection max_batch_featureValueDiff;
float max_batch_lossMinusModelScoreDiff = -1;
// Make constraints for new hypothesis translations
float epsilon = 0.0001;
int violatedConstraintsBefore = 0;
float oldDistanceFromOptimum = 0;
// iterate over input sentences (1 (online) or more (batch))
for (size_t i = 0; i < featureValuesHope.size(); ++i) {
size_t sentenceId = sentenceIds[i]; // keep sentenceId for storing more than 1 oracle..
// Pair all hope translations with all fear translations for one input sentence
for (size_t j = 0; j < featureValuesHope[i].size(); ++j) {
for (size_t k = 0; k < featureValuesFear[i].size(); ++k) {
ScoreComponentCollection featureValueDiff = featureValuesHope[i][j];
featureValueDiff.MinusEquals(featureValuesFear[i][k]);
cerr << "Rank " << rank << ", epoch " << epoch << ", feature value diff: " << featureValueDiff << endl;
if (featureValueDiff.GetL1Norm() == 0) {
// skip constraint
continue;
}
float loss = bleuScoresHope[i][j] - bleuScoresFear[i][k];
if (m_scale_margin == 1) {
loss *= bleuScoresHope[i][j];
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with oracle bleu score " << bleuScoresHope[i][j] << endl;
}
else if (m_scale_margin == 2) {
loss *= log2(bleuScoresHope[i][j]);
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with log2 oracle bleu score " << log2(bleuScoresHope[i][j]) << endl;
}
else if (m_scale_margin == 10) {
loss *= log10(bleuScoresHope[i][j]);
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with log10 oracle bleu score " << log10(bleuScoresHope[i][j]) << endl;
}
// check if constraint is violated
bool violated = false;
bool addConstraint = true;
float modelScoreDiff = featureValueDiff.InnerProduct(currWeights);
float diff = 0;
if (loss > (modelScoreDiff + m_margin_slack)) {
diff = loss - (modelScoreDiff + m_margin_slack);
}
cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " + " << m_margin_slack << " >= " << loss << " (current violation: " << diff << ")" << endl;
if (diff > epsilon) {
violated = true;
}
else if (m_onlyViolatedConstraints) {
addConstraint = false;
}
float lossMinusModelScoreDiff = loss - modelScoreDiff;
if (addConstraint) {
featureValueDiffs.push_back(featureValueDiff);
lossMinusModelScoreDiffs.push_back(lossMinusModelScoreDiff);
all_losses.push_back(loss);
if (violated) {
++violatedConstraintsBefore;
oldDistanceFromOptimum += diff;
}
}
}
}
}
// run optimisation: compute alphas for all given constraints
vector<float> alphas;
ScoreComponentCollection summedUpdate;
if (violatedConstraintsBefore > 0) {
cerr << "Rank " << rank << ", epoch " << epoch << ", number of constraints passed to optimizer: " <<
featureValueDiffs.size() << " (of which violated: " << violatedConstraintsBefore << ")" << endl;
if (m_slack != 0) {
alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs, m_slack);
} else {
alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs);
}
// Update the weight vector according to the alphas and the feature value differences
// * w' = w' + SUM alpha_i * (h_i(oracle) - h_i(hypothesis))
for (size_t k = 0; k < featureValueDiffs.size(); ++k) {
float alpha = alphas[k];
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", alpha: " << alpha << endl);
ScoreComponentCollection update(featureValueDiffs[k]);
update.MultiplyEquals(alpha);
// sum updates
summedUpdate.PlusEquals(update);
}
}
else {
cerr << "Rank " << rank << ", epoch " << epoch << ", check, no constraint violated for this batch" << endl;
return 0;
}
// apply learning rate
if (learning_rate != 1) {
cerr << "Rank " << rank << ", epoch " << epoch << ", apply learning rate " << learning_rate << " to update." << endl;
summedUpdate.MultiplyEquals(learning_rate);
}
// scale update by BLEU of oracle (for batch size 1 only)
if (featureValuesHope.size() == 1) {
if (m_scale_update == 1) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with oracle bleu score " << bleuScoresHope[0][0] << endl;
summedUpdate.MultiplyEquals(bleuScoresHope[0][0]);
}
else if (m_scale_update == 2) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with log2 oracle bleu score " << log2(bleuScoresHope[0][0]) << endl;
summedUpdate.MultiplyEquals(log2(bleuScoresHope[0][0]));
}
else if (m_scale_update == 10) {
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with log10 oracle bleu score " << log10(bleuScoresHope[0][0]) << endl;
summedUpdate.MultiplyEquals(log10(bleuScoresHope[0][0]));
}
}
cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << summedUpdate << endl;
// apply update to weight vector
currWeights.PlusEquals(summedUpdate);
// Sanity check: are there still violated constraints after optimisation?
int violatedConstraintsAfter = 0;
float newDistanceFromOptimum = 0;
for (size_t i = 0; i < featureValueDiffs.size(); ++i) {
float modelScoreDiff = featureValueDiffs[i].InnerProduct(currWeights);
float loss = all_losses[i];
float diff = loss - (modelScoreDiff + m_margin_slack);
if (diff > epsilon) {
++violatedConstraintsAfter;
newDistanceFromOptimum += diff;
}
}
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", violated constraint before: " << violatedConstraintsBefore << ", after: " << violatedConstraintsAfter << ", change: " << violatedConstraintsBefore - violatedConstraintsAfter << endl);
VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", error before: " << oldDistanceFromOptimum << ", after: " << newDistanceFromOptimum << ", change: " << oldDistanceFromOptimum - newDistanceFromOptimum << endl);
return violatedConstraintsAfter;
}
}