mirror of
https://github.com/moses-smt/mosesdecoder.git
synced 2024-12-28 14:32:38 +03:00
747 lines
30 KiB
C++
747 lines
30 KiB
C++
#include "Optimiser.h"
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#include "Hildreth.h"
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#include "moses/StaticData.h"
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using namespace Moses;
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using namespace std;
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namespace Mira
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{
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size_t MiraOptimiser::updateWeights(
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ScoreComponentCollection& weightUpdate,
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const vector<vector<ScoreComponentCollection> >& featureValues,
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const vector<vector<float> >& losses,
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const vector<vector<float> >& bleuScores,
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const vector<vector<float> >& modelScores,
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const vector<ScoreComponentCollection>& oracleFeatureValues,
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const vector<float> oracleBleuScores,
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const vector<float> oracleModelScores,
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float learning_rate,
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size_t rank,
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size_t epoch)
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{
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// vector of feature values differences for all created constraints
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vector<ScoreComponentCollection> featureValueDiffs;
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vector<float> lossMinusModelScoreDiffs;
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vector<float> all_losses;
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// most violated constraint in batch
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ScoreComponentCollection max_batch_featureValueDiff;
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// Make constraints for new hypothesis translations
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float epsilon = 0.0001;
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int violatedConstraintsBefore = 0;
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float oldDistanceFromOptimum = 0;
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// iterate over input sentences (1 (online) or more (batch))
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for (size_t i = 0; i < featureValues.size(); ++i) {
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//size_t sentenceId = sentenceIds[i];
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// iterate over hypothesis translations for one input sentence
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for (size_t j = 0; j < featureValues[i].size(); ++j) {
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ScoreComponentCollection featureValueDiff = oracleFeatureValues[i];
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featureValueDiff.MinusEquals(featureValues[i][j]);
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// cerr << "Rank " << rank << ", epoch " << epoch << ", feature value diff: " << featureValueDiff << endl;
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if (featureValueDiff.GetL1Norm() == 0) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
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continue;
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}
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float loss = losses[i][j];
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// check if constraint is violated
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bool violated = false;
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// float modelScoreDiff = featureValueDiff.InnerProduct(currWeights);
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float modelScoreDiff = oracleModelScores[i] - modelScores[i][j];
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float diff = 0;
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if (loss > modelScoreDiff)
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diff = loss - modelScoreDiff;
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cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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if (diff > epsilon)
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violated = true;
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if (m_normaliseMargin) {
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modelScoreDiff = (2*m_sigmoidParam/(1 + exp(-modelScoreDiff))) - m_sigmoidParam;
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loss = (2*m_sigmoidParam/(1 + exp(-loss))) - m_sigmoidParam;
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diff = 0;
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if (loss > modelScoreDiff) {
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diff = loss - modelScoreDiff;
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}
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cerr << "Rank " << rank << ", epoch " << epoch << ", normalised constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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}
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if (m_scale_margin) {
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diff *= oracleBleuScores[i];
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with oracle bleu score " << oracleBleuScores[i] << endl;
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}
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featureValueDiffs.push_back(featureValueDiff);
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lossMinusModelScoreDiffs.push_back(diff);
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all_losses.push_back(loss);
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if (violated) {
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++violatedConstraintsBefore;
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oldDistanceFromOptimum += diff;
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}
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}
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}
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// run optimisation: compute alphas for all given constraints
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vector<float> alphas;
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ScoreComponentCollection summedUpdate;
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if (violatedConstraintsBefore > 0) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", number of constraints passed to optimizer: " <<
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featureValueDiffs.size() << " (of which violated: " << violatedConstraintsBefore << ")" << endl;
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if (m_slack != 0) {
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alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs, m_slack);
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} else {
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alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs);
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}
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// Update the weight vector according to the alphas and the feature value differences
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// * w' = w' + SUM alpha_i * (h_i(oracle) - h_i(hypothesis))
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for (size_t k = 0; k < featureValueDiffs.size(); ++k) {
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float alpha = alphas[k];
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cerr << "Rank " << rank << ", epoch " << epoch << ", alpha: " << alpha << endl;
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ScoreComponentCollection update(featureValueDiffs[k]);
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update.MultiplyEquals(alpha);
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// sum updates
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summedUpdate.PlusEquals(update);
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}
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} else {
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cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
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// return 0;
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return 1;
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}
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// apply learning rate
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if (learning_rate != 1) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", apply learning rate " << learning_rate << " to update." << endl;
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summedUpdate.MultiplyEquals(learning_rate);
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}
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// scale update by BLEU of oracle (for batch size 1 only)
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if (oracleBleuScores.size() == 1) {
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if (m_scale_update) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with oracle bleu score " << oracleBleuScores[0] << endl;
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summedUpdate.MultiplyEquals(oracleBleuScores[0]);
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}
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}
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// cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << summedUpdate << endl;
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weightUpdate.PlusEquals(summedUpdate);
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// Sanity check: are there still violated constraints after optimisation?
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/* int violatedConstraintsAfter = 0;
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float newDistanceFromOptimum = 0;
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for (size_t i = 0; i < featureValueDiffs.size(); ++i) {
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float modelScoreDiff = featureValueDiffs[i].InnerProduct(currWeights);
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float loss = all_losses[i];
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float diff = loss - modelScoreDiff;
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if (diff > epsilon) {
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++violatedConstraintsAfter;
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newDistanceFromOptimum += diff;
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}
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}
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VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", violated constraint before: " << violatedConstraintsBefore << ", after: " << violatedConstraintsAfter << ", change: " << violatedConstraintsBefore - violatedConstraintsAfter << endl);
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VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", error before: " << oldDistanceFromOptimum << ", after: " << newDistanceFromOptimum << ", change: " << oldDistanceFromOptimum - newDistanceFromOptimum << endl);*/
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// return violatedConstraintsAfter;
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return 0;
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}
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size_t MiraOptimiser::updateWeightsHopeFear(
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Moses::ScoreComponentCollection& weightUpdate,
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const std::vector< std::vector<Moses::ScoreComponentCollection> >& featureValuesHope,
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const std::vector< std::vector<Moses::ScoreComponentCollection> >& featureValuesFear,
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const std::vector<std::vector<float> >& bleuScoresHope,
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const std::vector<std::vector<float> >& bleuScoresFear,
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const std::vector<std::vector<float> >& modelScoresHope,
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const std::vector<std::vector<float> >& modelScoresFear,
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float learning_rate,
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size_t rank,
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size_t epoch,
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int updatePosition)
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{
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// vector of feature values differences for all created constraints
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vector<ScoreComponentCollection> featureValueDiffs;
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vector<float> lossMinusModelScoreDiffs;
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vector<float> modelScoreDiffs;
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vector<float> all_losses;
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// most violated constraint in batch
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ScoreComponentCollection max_batch_featureValueDiff;
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// Make constraints for new hypothesis translations
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float epsilon = 0.0001;
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int violatedConstraintsBefore = 0;
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float oldDistanceFromOptimum = 0;
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// iterate over input sentences (1 (online) or more (batch))
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for (size_t i = 0; i < featureValuesHope.size(); ++i) {
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if (updatePosition != -1) {
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if (i < updatePosition)
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continue;
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else if (i > updatePosition)
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break;
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}
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// Pick all pairs[j,j] of hope and fear translations for one input sentence
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for (size_t j = 0; j < featureValuesHope[i].size(); ++j) {
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ScoreComponentCollection featureValueDiff = featureValuesHope[i][j];
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featureValueDiff.MinusEquals(featureValuesFear[i][j]);
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//cerr << "Rank " << rank << ", epoch " << epoch << ", feature value diff: " << featureValueDiff << endl;
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if (featureValueDiff.GetL1Norm() == 0) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
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continue;
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}
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float loss = bleuScoresHope[i][j] - bleuScoresFear[i][j];
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// check if constraint is violated
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bool violated = false;
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//float modelScoreDiff = featureValueDiff.InnerProduct(currWeights);
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float modelScoreDiff = modelScoresHope[i][j] - modelScoresFear[i][j];
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float diff = 0;
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if (loss > modelScoreDiff)
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diff = loss - modelScoreDiff;
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cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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if (diff > epsilon)
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violated = true;
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if (m_normaliseMargin) {
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modelScoreDiff = (2*m_sigmoidParam/(1 + exp(-modelScoreDiff))) - m_sigmoidParam;
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loss = (2*m_sigmoidParam/(1 + exp(-loss))) - m_sigmoidParam;
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diff = 0;
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if (loss > modelScoreDiff) {
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diff = loss - modelScoreDiff;
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}
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cerr << "Rank " << rank << ", epoch " << epoch << ", normalised constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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}
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if (m_scale_margin) {
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diff *= bleuScoresHope[i][j];
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with oracle bleu score " << bleuScoresHope[i][j] << endl;
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}
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featureValueDiffs.push_back(featureValueDiff);
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lossMinusModelScoreDiffs.push_back(diff);
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modelScoreDiffs.push_back(modelScoreDiff);
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all_losses.push_back(loss);
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if (violated) {
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++violatedConstraintsBefore;
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oldDistanceFromOptimum += diff;
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}
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}
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}
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// run optimisation: compute alphas for all given constraints
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vector<float> alphas;
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ScoreComponentCollection summedUpdate;
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if (violatedConstraintsBefore > 0) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", number of constraints passed to optimizer: " <<
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featureValueDiffs.size() << " (of which violated: " << violatedConstraintsBefore << ")" << endl;
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if (m_slack != 0) {
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alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs, m_slack);
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} else {
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alphas = Hildreth::optimise(featureValueDiffs, lossMinusModelScoreDiffs);
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}
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// Update the weight vector according to the alphas and the feature value differences
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// * w' = w' + SUM alpha_i * (h_i(oracle) - h_i(hypothesis))
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for (size_t k = 0; k < featureValueDiffs.size(); ++k) {
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float alpha = alphas[k];
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cerr << "Rank " << rank << ", epoch " << epoch << ", alpha: " << alpha << endl;
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if (alpha != 0) {
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// apply boosting factor
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if (m_boost && modelScoreDiffs[k] <= 0) {
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// factor between 1.5 and 3 (for Bleu scores between 5 and 20, the factor is within the boundaries)
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float factor = min(1.5, log2(bleuScoresHope[0][0])); // TODO: make independent of number of oracles!!
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factor = min(3.0f, factor);
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alpha = alpha * factor;
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cerr << "Rank " << rank << ", epoch " << epoch << ", apply boosting factor " << factor << " to update." << endl;
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}
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ScoreComponentCollection update(featureValueDiffs[k]);
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update.MultiplyEquals(alpha);
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// sum updates
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summedUpdate.PlusEquals(update);
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}
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}
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} else {
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cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
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// return 0;
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return 1;
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}
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// apply learning rate
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if (learning_rate != 1) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", apply learning rate " << learning_rate << " to update." << endl;
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summedUpdate.MultiplyEquals(learning_rate);
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}
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// scale update by BLEU of oracle (for batch size 1 only)
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if (featureValuesHope.size() == 1) {
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if (m_scale_update) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with oracle bleu score " << bleuScoresHope[0][0] << endl;
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summedUpdate.MultiplyEquals(bleuScoresHope[0][0]);
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}
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}
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//cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << summedUpdate << endl;
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weightUpdate.PlusEquals(summedUpdate);
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// Sanity check: are there still violated constraints after optimisation?
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/* int violatedConstraintsAfter = 0;
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float newDistanceFromOptimum = 0;
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for (size_t i = 0; i < featureValueDiffs.size(); ++i) {
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float modelScoreDiff = featureValueDiffs[i].InnerProduct(currWeights);
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float loss = all_losses[i];
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float diff = loss - modelScoreDiff;
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if (diff > epsilon) {
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++violatedConstraintsAfter;
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newDistanceFromOptimum += diff;
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}
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}
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VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", violated constraint before: " << violatedConstraintsBefore << ", after: " << violatedConstraintsAfter << ", change: " << violatedConstraintsBefore - violatedConstraintsAfter << endl);
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VERBOSE(1, "Rank " << rank << ", epoch " << epoch << ", error before: " << oldDistanceFromOptimum << ", after: " << newDistanceFromOptimum << ", change: " << oldDistanceFromOptimum - newDistanceFromOptimum << endl);*/
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// return violatedConstraintsAfter;
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return 0;
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}
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size_t MiraOptimiser::updateWeightsAnalytically(
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ScoreComponentCollection& weightUpdate,
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ScoreComponentCollection& featureValuesHope,
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ScoreComponentCollection& featureValuesFear,
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float bleuScoreHope,
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float bleuScoreFear,
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float modelScoreHope,
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float modelScoreFear,
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float learning_rate,
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size_t rank,
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size_t epoch)
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{
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float epsilon = 0.0001;
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float oldDistanceFromOptimum = 0;
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bool constraintViolatedBefore = false;
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// cerr << "Rank " << rank << ", epoch " << epoch << ", hope: " << featureValuesHope << endl;
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// cerr << "Rank " << rank << ", epoch " << epoch << ", fear: " << featureValuesFear << endl;
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ScoreComponentCollection featureValueDiff = featureValuesHope;
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featureValueDiff.MinusEquals(featureValuesFear);
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if (featureValueDiff.GetL1Norm() == 0) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
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return 1;
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}
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// cerr << "Rank " << rank << ", epoch " << epoch << ", hope - fear: " << featureValueDiff << endl;
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// float modelScoreDiff = featureValueDiff.InnerProduct(currWeights);
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float modelScoreDiff = modelScoreHope - modelScoreFear;
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float loss = bleuScoreHope - bleuScoreFear;
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float diff = 0;
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if (loss > modelScoreDiff)
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diff = loss - modelScoreDiff;
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cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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if (m_normaliseMargin) {
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modelScoreDiff = (2*m_sigmoidParam/(1 + exp(-modelScoreDiff))) - m_sigmoidParam;
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loss = (2*m_sigmoidParam/(1 + exp(-loss))) - m_sigmoidParam;
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if (loss > modelScoreDiff)
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diff = loss - modelScoreDiff;
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cerr << "Rank " << rank << ", epoch " << epoch << ", normalised constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
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}
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if (m_scale_margin) {
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diff *= bleuScoreHope;
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with oracle bleu score " << bleuScoreHope << endl;
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}
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if (m_scale_margin_precision) {
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diff *= (1+m_precision);
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling margin with 1+precision: " << (1+m_precision) << endl;
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}
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if (diff > epsilon) {
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// squash it between 0 and 1
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//diff = tanh(diff);
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//diff = (2/(1 + pow(2,-diff))) - 1;
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/* if (m_normaliseMargin) {
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diff = (2/(1 + exp(-diff))) - 1;
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cerr << "Rank " << rank << ", epoch " << epoch << ", new margin: " << diff << endl;
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}*/
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// constraint violated
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oldDistanceFromOptimum += diff;
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constraintViolatedBefore = true;
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// compute alpha for given constraint: (loss - model score diff) / || feature value diff ||^2
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// featureValueDiff.GetL2Norm() * featureValueDiff.GetL2Norm() == featureValueDiff.InnerProduct(featureValueDiff)
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// from Crammer&Singer 2006: alpha = min {C , l_t/ ||x||^2}
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float squaredNorm = featureValueDiff.GetL2Norm() * featureValueDiff.GetL2Norm();
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float alpha = diff / squaredNorm;
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cerr << "Rank " << rank << ", epoch " << epoch << ", unclipped alpha: " << alpha << endl;
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if (m_slack > 0 ) {
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if (alpha > m_slack) {
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alpha = m_slack;
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} else if (alpha < m_slack*(-1)) {
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alpha = m_slack*(-1);
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}
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}
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// apply learning rate
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if (learning_rate != 1)
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alpha = alpha * learning_rate;
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if (m_scale_update) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling update with oracle bleu score " << bleuScoreHope << endl;
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alpha *= bleuScoreHope;
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}
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if (m_scale_update_precision) {
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cerr << "Rank " << rank << ", epoch " << epoch << ", scaling update with 1+precision: " << (1+m_precision) << endl;
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alpha *= (1+m_precision);
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}
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cerr << "Rank " << rank << ", epoch " << epoch << ", clipped/scaled alpha: " << alpha << endl;
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// apply boosting factor
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if (m_boost && modelScoreDiff <= 0) {
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// factor between 1.5 and 3 (for Bleu scores between 5 and 20, the factor is within the boundaries)
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float factor = min(1.5, log2(bleuScoreHope));
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factor = min(3.0f, factor);
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alpha = alpha * factor;
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cerr << "Rank " << rank << ", epoch " << epoch << ", boosted alpha: " << alpha << endl;
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}
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featureValueDiff.MultiplyEquals(alpha);
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weightUpdate.PlusEquals(featureValueDiff);
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// cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << weightUpdate << endl;
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}
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if (!constraintViolatedBefore) {
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// constraint satisfied, nothing to do
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cerr << "Rank " << rank << ", epoch " << epoch << ", constraint already satisfied" << endl;
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return 1;
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}
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// sanity check: constraint still violated after optimisation?
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/* ScoreComponentCollection newWeights(currWeights);
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newWeights.PlusEquals(weightUpdate);
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bool constraintViolatedAfter = false;
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float newDistanceFromOptimum = 0;
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featureValueDiff = featureValuesHope;
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featureValueDiff.MinusEquals(featureValuesFear);
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modelScoreDiff = featureValueDiff.InnerProduct(newWeights);
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diff = loss - modelScoreDiff;
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// approximate comparison between floats!
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if (diff > epsilon) {
|
|
constraintViolatedAfter = true;
|
|
newDistanceFromOptimum += (loss - modelScoreDiff);
|
|
}
|
|
|
|
float hopeScore = featureValuesHope.InnerProduct(newWeights);
|
|
float fearScore = featureValuesFear.InnerProduct(newWeights);
|
|
cerr << "New hope score: " << hopeScore << endl;
|
|
cerr << "New fear score: " << fearScore << endl;
|
|
|
|
VERBOSE(0, "Rank " << rank << ", epoch " << epoch << ", check, constraint violated before? " << constraintViolatedBefore << ", after? " << constraintViolatedAfter << endl);
|
|
VERBOSE(0, "Rank " << rank << ", epoch " << epoch << ", check, error before: " << oldDistanceFromOptimum << ", after: " << newDistanceFromOptimum << ", change: " << oldDistanceFromOptimum - newDistanceFromOptimum << endl);
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
size_t MiraOptimiser::updateWeightsHopeFearSelective(
|
|
Moses::ScoreComponentCollection& weightUpdate,
|
|
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<std::vector<float> >& modelScoresHope,
|
|
const std::vector<std::vector<float> >& modelScoresFear,
|
|
float learning_rate,
|
|
size_t rank,
|
|
size_t epoch,
|
|
int updatePosition)
|
|
{
|
|
|
|
// vector of feature values differences for all created constraints
|
|
vector<ScoreComponentCollection> nonZeroFeatures;
|
|
vector<float> lossMinusModelScoreDiffs;
|
|
|
|
// Make constraints for new hypothesis translations
|
|
float epsilon = 0.0001;
|
|
int violatedConstraintsBefore = 0;
|
|
|
|
// iterate over input sentences (1 (online) or more (batch))
|
|
for (size_t i = 0; i < featureValuesHope.size(); ++i) {
|
|
if (updatePosition != -1) {
|
|
if (i < updatePosition)
|
|
continue;
|
|
else if (i > updatePosition)
|
|
break;
|
|
}
|
|
|
|
// Pick all pairs[j,j] of hope and fear translations for one input sentence
|
|
for (size_t j = 0; j < featureValuesHope[i].size(); ++j) {
|
|
ScoreComponentCollection featureValueDiff = featureValuesHope[i][j];
|
|
featureValueDiff.MinusEquals(featureValuesFear[i][j]);
|
|
if (featureValueDiff.GetL1Norm() == 0) {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
|
|
continue;
|
|
}
|
|
|
|
// check if constraint is violated
|
|
float loss = bleuScoresHope[i][j] - bleuScoresFear[i][j];
|
|
float modelScoreDiff = modelScoresHope[i][j] - modelScoresFear[i][j];
|
|
float diff = 0;
|
|
if (loss > modelScoreDiff)
|
|
diff = loss - modelScoreDiff;
|
|
if (diff > epsilon)
|
|
++violatedConstraintsBefore;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << loss << " (current violation: " << diff << ")" << endl;
|
|
|
|
// iterate over difference vector and add a constraint for every non-zero feature
|
|
FVector features = featureValueDiff.GetScoresVector();
|
|
size_t n_core = 0, n_sparse = 0, n_sparse_hope = 0, n_sparse_fear = 0;
|
|
for (size_t i=0; i<features.coreSize(); ++i) {
|
|
if (features[i] != 0.0) {
|
|
++n_core;
|
|
ScoreComponentCollection f;
|
|
f.Assign(i, features[i]);
|
|
nonZeroFeatures.push_back(f);
|
|
}
|
|
}
|
|
|
|
vector<ScoreComponentCollection> nonZeroFeaturesHope;
|
|
vector<ScoreComponentCollection> nonZeroFeaturesFear;
|
|
for (FVector::iterator i = features.begin(); i != features.end(); ++i) {
|
|
if (i->second != 0.0) {
|
|
ScoreComponentCollection f;
|
|
f.Assign((i->first).name(), i->second);
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", f: " << f << endl;
|
|
|
|
if (i->second > 0.0) {
|
|
++n_sparse_hope;
|
|
nonZeroFeaturesHope.push_back(f);
|
|
} else {
|
|
++n_sparse_fear;
|
|
nonZeroFeaturesFear.push_back(f);
|
|
}
|
|
}
|
|
}
|
|
|
|
float n = n_core + n_sparse_hope + n_sparse_fear;
|
|
for (size_t i=0; i<n_core; ++i)
|
|
lossMinusModelScoreDiffs.push_back(diff/n);
|
|
for (size_t i=0; i<n_sparse_hope; ++i) {
|
|
nonZeroFeatures.push_back(nonZeroFeaturesHope[i]);
|
|
lossMinusModelScoreDiffs.push_back((diff/n)*1.1);
|
|
}
|
|
for (size_t i=0; i<n_sparse_fear; ++i) {
|
|
nonZeroFeatures.push_back(nonZeroFeaturesFear[i]);
|
|
lossMinusModelScoreDiffs.push_back(diff/n);
|
|
}
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", core diff: " << diff/n << endl;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", hope diff: " << ((diff/n)*1.1) << endl;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", fear diff: " << diff/n << endl;
|
|
}
|
|
}
|
|
|
|
assert(nonZeroFeatures.size() == lossMinusModelScoreDiffs.size());
|
|
|
|
// 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: " << nonZeroFeatures.size() << endl;
|
|
alphas = Hildreth::optimise(nonZeroFeatures, lossMinusModelScoreDiffs, m_slack);
|
|
|
|
// 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 < nonZeroFeatures.size(); ++k) {
|
|
float alpha = alphas[k];
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", alpha: " << alpha << endl;
|
|
if (alpha != 0) {
|
|
ScoreComponentCollection update(nonZeroFeatures[k]);
|
|
update.MultiplyEquals(alpha);
|
|
|
|
// sum updates
|
|
summedUpdate.PlusEquals(update);
|
|
}
|
|
}
|
|
} else {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
|
|
// return 0;
|
|
return 1;
|
|
}
|
|
|
|
// 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) {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", scaling summed update with oracle bleu score " << bleuScoresHope[0][0] << endl;
|
|
summedUpdate.MultiplyEquals(bleuScoresHope[0][0]);
|
|
}
|
|
}
|
|
|
|
//cerr << "Rank " << rank << ", epoch " << epoch << ", update: " << summedUpdate << endl;
|
|
weightUpdate.PlusEquals(summedUpdate);
|
|
return 0;
|
|
}
|
|
|
|
size_t MiraOptimiser::updateWeightsHopeFearSummed(
|
|
Moses::ScoreComponentCollection& weightUpdate,
|
|
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<std::vector<float> >& modelScoresHope,
|
|
const std::vector<std::vector<float> >& modelScoresFear,
|
|
float learning_rate,
|
|
size_t rank,
|
|
size_t epoch,
|
|
bool rescaleSlack,
|
|
bool makePairs)
|
|
{
|
|
|
|
// vector of feature values differences for all created constraints
|
|
ScoreComponentCollection averagedFeatureDiffs;
|
|
float averagedViolations = 0;
|
|
|
|
// Make constraints for new hypothesis translations
|
|
float epsilon = 0.0001;
|
|
int violatedConstraintsBefore = 0;
|
|
|
|
if (!makePairs) {
|
|
ScoreComponentCollection featureValueDiff;
|
|
float lossHope = 0, lossFear = 0, modelScoreHope = 0, modelScoreFear = 0, hopeCount = 0, fearCount = 0;
|
|
// add all hope vectors
|
|
for (size_t i = 0; i < featureValuesHope.size(); ++i) {
|
|
for (size_t j = 0; j < featureValuesHope[i].size(); ++j) {
|
|
featureValueDiff.PlusEquals(featureValuesHope[i][j]);
|
|
lossHope += bleuScoresHope[i][j];
|
|
modelScoreHope += modelScoresHope[i][j];
|
|
++hopeCount;
|
|
}
|
|
}
|
|
lossHope /= hopeCount;
|
|
modelScoreHope /= hopeCount;
|
|
|
|
// subtract all fear vectors
|
|
for (size_t i = 0; i < featureValuesFear.size(); ++i) {
|
|
for (size_t j = 0; j < featureValuesFear[i].size(); ++j) {
|
|
featureValueDiff.MinusEquals(featureValuesFear[i][j]);
|
|
lossFear += bleuScoresFear[i][j];
|
|
modelScoreFear += modelScoresFear[i][j];
|
|
++fearCount;
|
|
}
|
|
}
|
|
lossFear /= fearCount;
|
|
modelScoreFear /= fearCount;
|
|
|
|
if (featureValueDiff.GetL1Norm() == 0) {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
|
|
return 1;
|
|
}
|
|
|
|
// check if constraint is violated
|
|
float lossDiff = lossHope - lossFear;
|
|
float modelScoreDiff = modelScoreHope - modelScoreFear;
|
|
float diff = 0;
|
|
if (lossDiff > modelScoreDiff)
|
|
diff = lossDiff - modelScoreDiff;
|
|
if (diff > epsilon)
|
|
++violatedConstraintsBefore;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << lossDiff << " (current violation: " <<\
|
|
diff << ")" << endl;
|
|
|
|
// add constraint
|
|
averagedFeatureDiffs = featureValueDiff;
|
|
averagedViolations = diff;
|
|
} else {
|
|
// iterate over input sentences (1 (online) or more (batch))
|
|
for (size_t i = 0; i < featureValuesHope.size(); ++i) {
|
|
// Pick all pairs[j,j] of hope and fear translations for one input sentence and add them up
|
|
for (size_t j = 0; j < featureValuesHope[i].size(); ++j) {
|
|
ScoreComponentCollection featureValueDiff = featureValuesHope[i][j];
|
|
featureValueDiff.MinusEquals(featureValuesFear[i][j]);
|
|
if (featureValueDiff.GetL1Norm() == 0) {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", features equal --> skip" << endl;
|
|
continue;
|
|
}
|
|
|
|
// check if constraint is violated
|
|
float lossDiff = bleuScoresHope[i][j] - bleuScoresFear[i][j];
|
|
float modelScoreDiff = modelScoresHope[i][j] - modelScoresFear[i][j];
|
|
if (rescaleSlack) {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", modelScoreDiff scaled by lossDiff: " << modelScoreDiff << " --> " << modelScoreDiff*lossDiff << endl;
|
|
modelScoreDiff *= lossDiff;
|
|
}
|
|
float diff = 0;
|
|
if (lossDiff > modelScoreDiff)
|
|
diff = lossDiff - modelScoreDiff;
|
|
if (diff > epsilon)
|
|
++violatedConstraintsBefore;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", constraint: " << modelScoreDiff << " >= " << lossDiff << " (current violation: " << diff << ")" << endl;
|
|
|
|
// add constraint
|
|
if (rescaleSlack) {
|
|
averagedFeatureDiffs.MultiplyEquals(lossDiff);
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", featureValueDiff scaled by lossDiff." << endl;
|
|
}
|
|
averagedFeatureDiffs.PlusEquals(featureValueDiff);
|
|
averagedViolations += diff;
|
|
}
|
|
}
|
|
}
|
|
|
|
// divide by number of constraints (1/n)
|
|
if (!makePairs) {
|
|
averagedFeatureDiffs.DivideEquals(featureValuesHope[0].size());
|
|
} else {
|
|
averagedFeatureDiffs.DivideEquals(featureValuesHope[0].size());
|
|
averagedViolations /= featureValuesHope[0].size();
|
|
}
|
|
//cerr << "Rank " << rank << ", epoch " << epoch << ", averaged feature diffs: " << averagedFeatureDiffs << endl;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", averaged violations: " << averagedViolations << endl;
|
|
|
|
if (violatedConstraintsBefore > 0) {
|
|
// compute alpha for given constraint: (loss diff - model score diff) / || feature value diff ||^2
|
|
// featureValueDiff.GetL2Norm() * featureValueDiff.GetL2Norm() == featureValueDiff.InnerProduct(featureValueDiff)
|
|
// from Crammer&Singer 2006: alpha = min {C , l_t/ ||x||^2}
|
|
// adjusted for 1 slack according to Joachims 2009, OP4 (margin rescaling), OP5 (slack rescaling)
|
|
float squaredNorm = averagedFeatureDiffs.GetL2Norm() * averagedFeatureDiffs.GetL2Norm();
|
|
float alpha = averagedViolations / squaredNorm;
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", unclipped alpha: " << alpha << endl;
|
|
if (m_slack > 0 ) {
|
|
if (alpha > m_slack) {
|
|
alpha = m_slack;
|
|
} else if (alpha < m_slack*(-1)) {
|
|
alpha = m_slack*(-1);
|
|
}
|
|
}
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", clipped alpha: " << alpha << endl;
|
|
|
|
// compute update
|
|
averagedFeatureDiffs.MultiplyEquals(alpha);
|
|
weightUpdate.PlusEquals(averagedFeatureDiffs);
|
|
return 0;
|
|
} else {
|
|
cerr << "Rank " << rank << ", epoch " << epoch << ", no constraint violated for this batch" << endl;
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
}
|
|
|