double GradientCRF::computeGradient(dVector& vecGradient, Model* m,
DataSequence* X)
{
//compute beliefs
Beliefs bel;
pInfEngine->computeBeliefs(bel,pFeatureGen, X, m, false);
double phi = pFeatureGen->evaluateLabels(X,m);
double partition = bel.partition;
//Get adjency matrix
uMatrix adjMat;
m->getAdjacencyMatrix(adjMat, X);
//Check the size of vecGradient
int nbFeatures = pFeatureGen->getNumberOfFeatures();
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
#if !defined(_VEC_FEATURES) && !defined(_OPENMP)
featureVector* vecFeatures;
#endif
#if defined(_OPENMP)
int ThreadID = omp_get_thread_num();
if (ThreadID >= nbThreadsMP)
ThreadID = 0;
#else
int ThreadID = 0;
#endif
//Loop over nodes to compute features and update the gradient
for(int i = 0; i < X->length(); i++)
{
// Read the label for this state
int s = X->getStateLabels(i);
//Get nodes features
#if defined(_VEC_FEATURES) || defined(_OPENMP)
pFeatureGen->getFeatures(vecFeaturesMP[ThreadID], X,m,i,-1);
// Loop over features
feature* pFeature = vecFeaturesMP[ThreadID].getPtr();
for(int j = 0; j < vecFeaturesMP[ThreadID].size(); j++, pFeature++)
#else
vecFeatures = pFeatureGen->getFeatures(X,m,i,-1);
// Loop over features
feature* pFeature = vecFeatures->getPtr();
for(int j = 0; j < vecFeatures->size(); j++, pFeature++)
#endif
{
// If feature has same state label as the label from the
// dataSequence, then add this to the gradient
if(pFeature->nodeState == s)
vecGradient[pFeature->id] += pFeature->value;
//p(y_i=s|x)*f_k(i,s,x) is subtracted from the gradient
vecGradient[pFeature->id] -= bel.belStates[i][pFeature->nodeState]*pFeature->value;
}
}
//Loop over edges to compute features and update the gradient
int edgeIndex = 0;
for(int row = 0; row < X->length(); row++) // Loop over all rows (the previous node index)
{
for(int col = row; col < X->length() ; col++) //Loop over all columns (the current node index)
{
if(adjMat(row,col) == 1)
{
int s1 = X->getStateLabels(row);
int s2 = X->getStateLabels(col);
//Get nodes features
#if defined(_VEC_FEATURES) || defined(_OPENMP)
pFeatureGen->getFeatures(vecFeaturesMP[ThreadID], X,m,col,row);
// Loop over features
feature* pFeature = vecFeaturesMP[ThreadID].getPtr();
for(int j = 0; j < vecFeaturesMP[ThreadID].size(); j++, pFeature++)
#else
vecFeatures = pFeatureGen->getFeatures(X,m,col,row);
// Loop over features
feature* pFeature = vecFeatures->getPtr();
for(int j = 0; j < vecFeatures->size(); j++, pFeature++)
#endif
{
// ++ Forward edge ++
// If edge feature has same state labels as the labels from the dataSequence, then add it to the gradient
if(pFeature->nodeState == s2 && pFeature->prevNodeState == s1)
vecGradient[pFeature->id] += pFeature->value;
//p(y_i=s1,y_j=s2|x)*f_k(i,j,s1,s2,x) is subtracted from the gradient
vecGradient[pFeature->id] -= bel.belEdges[edgeIndex](pFeature->prevNodeState,pFeature->nodeState)*pFeature->value;
}
edgeIndex++;
}
}
}
//Return -log instead of log() [Moved to Gradient::ComputeGradient by LP]
// vecGradient.negate();
return partition-phi;
}
double GradientHCRF::computeGradient(dVector& vecGradient, Model* m, DataSequence* X)
{
int nbFeatures = pFeatureGen->getNumberOfFeatures();
int NumSeqLabels=m->getNumberOfSequenceLabels();
//Get adjency matrix
uMatrix adjMat;
m->getAdjacencyMatrix(adjMat, X);
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
dVector Partition;
Partition.resize(1,NumSeqLabels);
std::vector<Beliefs> ConditionalBeliefs(NumSeqLabels);
// Step 1 : Run Inference in each network to compute marginals conditioned on Y
for(int i=0; i<NumSeqLabels; i++)
{
pInfEngine->computeBeliefs(ConditionalBeliefs[i],pFeatureGen, X, m, true,i);
Partition[i] = ConditionalBeliefs[i].partition;
}
double f_value = Partition.logSumExp() - Partition[X->getSequenceLabel()];
// Step 2: Compute expected values for feature nodes conditioned on Y
#if !defined(_VEC_FEATURES) && !defined(_OPENMP)
featureVector* vecFeatures;
#endif
#if defined(_OPENMP)
int ThreadID = omp_get_thread_num();
if (ThreadID >= nbThreadsMP)
ThreadID = 0;
#else
int ThreadID = 0;
#endif
double value;
dMatrix CEValues;
CEValues.resize(nbFeatures,NumSeqLabels);
//Loop over nodes to compute features and update the gradient
for(int j=0; j<NumSeqLabels; j++) { //For every labels
for(int i = 0; i < X->length(); i++) {//For every nodes
#if defined(_VEC_FEATURES) || defined(_OPENMP)
pFeatureGen->getFeatures(vecFeaturesMP[ThreadID], X,m,i,-1,j);
// Loop over features
feature* pFeature = vecFeaturesMP[ThreadID].getPtr();
for(int k = 0; k < vecFeaturesMP[ThreadID].size(); k++, pFeature++)
#else
vecFeatures =pFeatureGen->getFeatures(X,m,i,-1,j);
// Loop over features
feature* pFeature = vecFeatures->getPtr();
for(int k = 0; k < vecFeatures->size(); k++, pFeature++)
#endif
{
//p(s_i=s|x,Y) * f_k(i,s,x,y)
value=ConditionalBeliefs[j].belStates[i][pFeature->nodeState] * pFeature->value;
CEValues.setValue(j,pFeature->globalId, CEValues(j,pFeature->globalId) + value); // one row for each Y
}// end for every feature
}// end for every node
}// end for ever Sequence Label
// Step 3: Compute expected values for edge features conditioned on Y
//Loop over edges to compute features and update the gradient
for(int j=0; j<NumSeqLabels; j++) {
int edgeIndex = 0;
for(int row = 0; row < X->length(); row++) {
// Loop over all rows (the previous node index)
for(int col = row; col < X->length() ; col++) {
//Loop over all columns (the current node index)
if(adjMat(row,col) == 1) {
//Get nodes features
#if defined(_VEC_FEATURES) || defined(_OPENMP)
pFeatureGen->getFeatures(vecFeaturesMP[ThreadID], X,m,col,row,j);
// Loop over features
feature* pFeature = vecFeaturesMP[ThreadID].getPtr();
for(int k = 0; k < vecFeaturesMP[ThreadID].size(); k++, pFeature++)
#else
vecFeatures = pFeatureGen->getFeatures(X,m,col,row,j);
// Loop over features
feature* pFeature = vecFeatures->getPtr();
for(int k = 0; k < vecFeatures->size(); k++, pFeature++)
#endif
{
//p(y_i=s1,y_j=s2|x,Y)*f_k(i,j,s1,s2,x,y)
value=ConditionalBeliefs[j].belEdges[edgeIndex](pFeature->prevNodeState,pFeature->nodeState) * pFeature->value;
CEValues.setValue(j,pFeature->globalId, CEValues(j,pFeature->globalId) + value);
}
edgeIndex++;
}
}
}
}
// Step 4: Compute Joint Expected Values
dVector JointEValues;
JointEValues.resize(1,nbFeatures);
JointEValues.set(0);
dVector rowJ;
rowJ.resize(1,nbFeatures);
dVector GradientVector;
double sumZLog=Partition.logSumExp();
for (int j=0; j<NumSeqLabels; j++)
{
CEValues.getRow(j, rowJ);
rowJ.multiply(exp(Partition.getValue(j)-sumZLog));
JointEValues.add(rowJ);
}
// Step 5 Compute Gradient as Exi[i,*,*] -Exi[*,*,*], that is difference
// between expected values conditioned on Sequence Labels and Joint expected
// values
CEValues.getRow(X->getSequenceLabel(), rowJ); // rowJ=Expected value
// conditioned on Sequence
// label Y
// [Negation moved to Gradient::ComputeGradient by LP]
// rowJ.negate();
JointEValues.negate();
rowJ.add(JointEValues);
vecGradient.add(rowJ);
return f_value;
}
double Gradient::computeGradient(dVector& vecGradient, Model* m, DataSet* X)
{
double ans = 0.0;
#ifdef _OPENMP
if( nbThreadsMP < 1 )
nbThreadsMP = omp_get_max_threads();
setMaxNumberThreads(nbThreadsMP);
pInfEngine->setMaxNumberThreads(nbThreadsMP);
pFeatureGen->setMaxNumberThreads(nbThreadsMP);
#endif
//Check the size of vecGradient
int nbFeatures = pFeatureGen->getNumberOfFeatures();
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
else
vecGradient.set(0);
////////////////////////////////////////////////////////////
// Start of parallel Region
// Some weird stuff in gcc 4.1, with openmp 2.5 support
//
// Note 1: In OpenMP 2.5, the iteration variable in "for" must be
// a signed integer variable type. In OpenMP 3.0 (_OPENMP>=200805),
// it may also be an unsigned integer variable type, a pointer type,
// or a constant-time random access iterator type.
//
// Note 2: schedule(static | dynamic): In the dynamic schedule, there
// is no predictable order in which the loop items are assigned to
// different threads. Each thread asks the OpenMP runtime library for
// an iteration number, then handles it, then asks for the next one.
// It is thus useful when different iterations in the loop may take
// different time to execute.
#pragma omp parallel default(none) \
shared(vecGradient, X, m, ans, nbFeatures, std::cout)
{
// code inside this region runs in parallel
dVector g(nbFeatures, COLVECTOR, 0.0);
#pragma omp for schedule(dynamic) reduction(+:ans)
for(int i=0; (int)i<X->size(); i++) {
DataSequence* x = X->at(i);
if( m->isWeightSequence() && x->getWeightSequence() != 1.0) {
dVector tmp(nbFeatures, COLVECTOR, 0.0);
ans += computeGradient(tmp, m, x) * x->getWeightSequence();
tmp.multiply(x->getWeightSequence());
g.add(tmp);
}
else {
ans += computeGradient(g, m, x);
}
}
// We now put togheter the gradients
// No two threads can execute a critical directive of the same name at the same time
#pragma omp critical (reduce_sum)
{
vecGradient.add(g);
}
}
// End of parallel Region
////////////////////////////////////////////////////////////
vecGradient.negate();
// MaxMargin objective: min L = 0.5*\L2sigma*W*W + Loss()
// MLE objective: min L = 0.5*1/(\L2sigma*\L2sigma)*W*W - log p(y|x)
// Add the regularization term
double scale = (m->isMaxMargin())
? m->getRegL2Sigma()
: 1/(double)(m->getRegL2Sigma()*m->getRegL2Sigma());
if( m->isMaxMargin() )
ans = (1/(double)X->size()) * ans;
if(m->getRegL2Sigma()!=0.0f)
{
for(int f=0; f<nbFeatures; f++)
vecGradient[f] += (*m->getWeights())[f]*scale;
ans += 0.5*scale*m->getWeights()->l2Norm(false);
}
return ans;
}
// Based on A.2 Structured Loss in Teo et al. JMLR 2010, p343-344,
double GradientCRF::computeGradientMaxMargin(dVector& vecGradient, Model* m, DataSequence* X)
{
int xi, xj, yi, yj, k, nbFeatures;
double val, phi_star=0, phi_true=0, hamming_loss=0;
Beliefs bel;
pInfEngine->computeBeliefs(bel,pFeatureGen, X, m, false);
// Compute Hamming loss
iVector ystar; dVector pystar;
viterbiDecoding(bel,ystar,pystar);
for(xi=0; xi<X->length(); xi++)
if( X->getStateLabels(xi) != ystar[xi] )
hamming_loss++;
// Compute gradients
feature* f;
featureVector vecFeatures;
nbFeatures = pFeatureGen->getNumberOfFeatures();
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
dVector *w = m->getWeights();
dVector localGrad(nbFeatures);
// Loop over nodes to compute features and update the gradient
for(xi=0; xi<X->length(); xi++)
{
// Read the label for this state
yi = X->getStateLabels(xi);
//Get nodes features
pFeatureGen->getFeatures(vecFeatures,X,m,xi,-1);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++) {
if(f->nodeState==yi) {
phi_true += w->getValue(f->id) * f->value;
localGrad[f->id] -= f->value;
}
else if(f->nodeState==ystar[xi]) {
phi_star += w->getValue(f->id) * f->value;
localGrad[f->id] += f->value;
}
val = bel.belStates[xi][f->nodeState]*f->value;
vecGradient[f->id] -= val;
}
}
//Loop over edges to compute features and update the gradient
for(xi=0; xi<X->length()-1; xi++) {
xj = xi+1;
yi = X->getStateLabels(xi);
yj = X->getStateLabels(xj);
//Get nodes features
pFeatureGen->getFeatures(vecFeatures,X,m,xj,xi);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++)
{
if(f->prevNodeState == yi && f->nodeState == yj) {
phi_true += w->getValue(f->id) * f->value;
localGrad[f->id] -= f->value;
}
else if(f->prevNodeState==ystar[xi] && f->nodeState==ystar[xj]) {
phi_star += w->getValue(f->id) * f->value;
localGrad[f->id] += f->value;
}
val = bel.belEdges[xi](f->prevNodeState,f->nodeState)*f->value;
localGrad[f->id] -= val;
}
}
// Taskar et al. (2004) vs Tsochantaridis et al. (2005)
bool useTaskar = false;
double scale = (useTaskar) ? 1 : hamming_loss;
// Done!
localGrad.multiply(scale);
vecGradient.add(localGrad);
return hamming_loss + scale*(exp(phi_star-bel.partition) - exp(phi_true-bel.partition));
}
double GradientCRF::computeGradientMLE(dVector& vecGradient, Model* m, DataSequence* X)
{
int xi, xj, yi, yj, k, nbFeatures;
double val, phi, partition;
Beliefs bel;
// Compute beliefs
pInfEngine->computeBeliefs(bel,pFeatureGen, X, m, false);
phi = pFeatureGen->evaluateLabels(X,m);
partition = bel.partition;
// Compute gradients
// Check the size of vecGradient
nbFeatures = pFeatureGen->getNumberOfFeatures();
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
feature* f;
featureVector vecFeatures;
// Loop over nodes to compute features and update the gradient
for(xi=0; xi<X->length(); xi++) {
yi = X->getStateLabels(xi);
//Get nodes features
pFeatureGen->getFeatures(vecFeatures,X,m,xi,-1);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++)
{
if(f->nodeState == yi)
vecGradient[f->id] += f->value;
// p(y_i=s|x)*f_k(xi,s,x) is subtracted from the gradient
val = bel.belStates[xi][f->nodeState]*f->value;
vecGradient[f->id] -= val;
}
}
//Loop over edges to compute features and update the gradient
for(xi=0; xi<X->length()-1; xi++) {
xj = xi+1;
yi = X->getStateLabels(xi);
yj = X->getStateLabels(xj);
//Get nodes features
pFeatureGen->getFeatures(vecFeatures,X,m,xj,xi);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++)
{
if(f->prevNodeState == yi && f->nodeState == yj)
vecGradient[f->id] += f->value;
//p(y_i=s1,y_j=s2|x)*f_k(i,j,s1,s2,x) is subtracted from the gradient
val = bel.belEdges[xi](f->prevNodeState,f->nodeState)*f->value;
vecGradient[f->id] -= val;
}
}
//Return -log instead of log() [Moved to Gradient::ComputeGradient by LP]
return partition-phi;
}
double Gradient::computeGradient(dVector& vecGradient, Model* m, DataSet* X)
{
//Check the size of vecGradient
int nbFeatures = pFeatureGen->getNumberOfFeatures();
double ans = 0.0;
int TID = 0;
if(vecGradient.getLength() != nbFeatures)
vecGradient.create(nbFeatures);
else
vecGradient.set(0);
// Initialize the buffers (vecFeaturesMP) for each thread
#ifdef _OPENMP
setMaxNumberThreads(omp_get_max_threads());
pInfEngine->setMaxNumberThreads(omp_get_max_threads());
pFeatureGen->setMaxNumberThreads(omp_get_max_threads());
#endif
for(int t=0;t<nbThreadsMP;t++)
{
if(localGrads[t].getLength() != nbFeatures)
localGrads[t].resize(1,nbFeatures,0);
else
localGrads[t].set(0);
}
////////////////////////////////////////////////////////////
// Start of parallel Region
// Some weird stuff in gcc 4.1, with openmp 2.5 support
#if ((_OPENMP == 200505) && __GNUG__)
#pragma omp parallel \
shared(X, m, ans, nbFeatures, std::cout) \
private(TID) \
default(none)
#else
#pragma omp parallel \
shared(vecGradient, X, m, ans, nbFeatures, std::cout) \
private(TID) \
default(none)
#endif
{
#ifdef _OPENMP
TID = omp_get_thread_num();
#endif
// Create a temporary gradient
double localSum = 0;
#ifdef WITH_SEQUENCE_WEIGHTS
dVector tmpVecGradient(nbFeatures);
#endif
#pragma omp for
// we can use unsigned if we have openmp 3.0 support (_OPENMP>=200805).
#ifdef _OPENMP
#if _OPENMP >= 200805
for(unsigned int i = 0; i< X->size(); i++){
#else
for(int i = 0; i< X->size(); i++){
#endif
#else
for(unsigned int i = 0; i< X->size(); i++){
#endif
if (m->getDebugLevel() >=2){
#pragma omp critical(output)
std::cout << "Thread "<<TID<<" computes gradient for sequence "
<< i <<" out of " << (int)X->size()
<< " (Size: " << X->at(i)->length() << ")" << std::endl;
}
DataSequence* x = X->at(i);
#ifdef WITH_SEQUENCE_WEIGHTS
tmpVecGradient.set(0);
localSum += computeGradient(tmpVecGradient, m, x) * x->getWeightSequence();
if(x->getWeightSequence() != 1.0)
tmpVecGradient.multiply(x->getWeightSequence());
localGrads[TID].add(tmpVecGradient);
#else
localSum += computeGradient(localGrads[TID], m, x);// * x->getWeightSequence();
#endif
}
#pragma omp critical (reduce_sum)
// We now put togheter the sums
{
if( m->getDebugLevel() >= 2){
std::cout<<"Thread "<<TID<<" update sums"<<std::endl;
}
ans += localSum;
vecGradient.add(localGrads[TID]);
}
}
// End of parallel Region
////////////////////////////////////////////////////////////
// because we are minimizing -LogP
vecGradient.negate();
// Add the regularization term
double sigmaL2Square = m->getRegL2Sigma()*m->getRegL2Sigma();
if(sigmaL2Square != 0.0f) {
if (m->getDebugLevel() >= 2){
std::cout << "Adding L2 norm gradient\n";
}
for(int f = 0; f < nbFeatures; f++) {
vecGradient[f] += (*m->getWeights())[f]/sigmaL2Square;
}
double weightNorm = m->getWeights()->l2Norm(false);
ans += weightNorm / (2.0*m->getRegL2Sigma()*m->getRegL2Sigma());
}
return ans;
}
double GradientMVHCRF::computeGradientMLE(dVector& vecGradient, Model* m, DataSequence* X)
{
double f_value=0; // return value
////////////////////////////////////////////////////////////////////////////////////
// Step 1 : Run Inference in each network to compute marginals conditioned on Y
int nbSeqLabels = m->getNumberOfSequenceLabels();
std::vector<Beliefs> condBeliefs(nbSeqLabels);
dVector Partition(nbSeqLabels);
for(int y=0; y<nbSeqLabels; y++)
{
pInfEngine->computeBeliefs(condBeliefs[y], pFeatureGen, X, m, true, y);
Partition[y] = condBeliefs[y].partition;;
}
////////////////////////////////////////////////////////////////////////////////////
// Step 2 : Compute expected values for node/edge features conditioned on Y
int nbFeatures = pFeatureGen->getNumberOfFeatures();
dMatrix condEValues(nbFeatures, nbSeqLabels);
feature* f;
featureVector vecFeatures;
iMatrix adjMat;
m->getAdjacencyMatrixMV(adjMat, X);
int V = m->getNumberOfViews();
int T = X->length();
int nbNodes= V*T;
double val;
int y, k, xi, xj;
for(y=0; y<nbSeqLabels; y++)
{
// Loop over nodes to compute features and update the gradient
for(xi=0; xi<nbNodes; xi++) {
pFeatureGen->getFeatures(vecFeatures,X,m,xi,-1,y);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++) {
// p(h^v_t=a|x,y) * f_k(v,t,a,x,y)
val = condBeliefs[y].belStates[xi][f->nodeState] * f->value;
condEValues.addValue(y, f->globalId, val);
}
}
// Loop over edges to compute features and update the gradient
for(xi=0; xi<nbNodes; xi++) {
for(xj=xi+1; xj<nbNodes; xj++) {
if( !adjMat(xi,xj) ) continue;
pFeatureGen->getFeatures(vecFeatures,X,m,xj,xi,y);
f = vecFeatures.getPtr();
for(k=0; k<vecFeatures.size(); k++, f++) {
// p(h^vi_ti=a,h^vj_tj=b|x,y) * f_k(vi,ti,vj,tj,x,y)
val = condBeliefs[y].belEdges[adjMat(xi,xj)-1]
(f->prevNodeState,f->nodeState) * f->value;
condEValues.addValue(y, f->globalId, val);
}
}
}
}
////////////////////////////////////////////////////////////////////////////////////
// Step 3: Compute Joint Expected Values
dVector JointEValues(nbFeatures);
dVector rowJ(nbFeatures); // expected value conditioned on seqLabel Y
double sumZLog = Partition.logSumExp();
for (int y=0; y<nbSeqLabels; y++)
{
condEValues.getRow(y, rowJ);
rowJ.multiply( exp(Partition[y]-sumZLog) );
JointEValues.add(rowJ);
}
////////////////////////////////////////////////////////////////////////////////////
// Step 4 Compute Gradient as Exi[i,*,*] - Exi[*,*,*], that is the difference between
// expected values conditioned on seqLabel Y and joint expected values
if( vecGradient.getLength() != nbFeatures )
vecGradient.create(nbFeatures);
condEValues.getRow(X->getSequenceLabel(), rowJ);
JointEValues.negate();
rowJ.add(JointEValues);
vecGradient.add(rowJ);
// MLE: return log(sum_y' p(y'|xi)) - log(p(yi|xi)})
f_value = Partition.logSumExp() - Partition[X->getSequenceLabel()];
return f_value;
}