void
VarElim::eliminate (VarId elimVar)
{
Factor* result = 0;
vector<size_t>& idxs = varFactors_.find (elimVar)->second;
for (size_t i = 0; i < idxs.size(); i++) {
size_t idx = idxs[i];
if (factorList_[idx]) {
if (result == 0) {
result = new Factor (*factorList_[idx]);
} else {
result->multiply (*factorList_[idx]);
}
delete factorList_[idx];
factorList_[idx] = 0;
}
}
totalFactorSize_ += result->size();
if (result->size() > largestFactorSize_) {
largestFactorSize_ = result->size();
}
if (result != 0 && result->nrArguments() != 1) {
result->sumOut (elimVar);
factorList_.push_back (result);
const VarIds& resultVarIds = result->arguments();
for (size_t i = 0; i < resultVarIds.size(); i++) {
vector<size_t>& idxs =
varFactors_.find (resultVarIds[i])->second;
idxs.push_back (factorList_.size() - 1);
}
}
}
Params
BeliefProp::getFactorJoint (
FacNode* fn,
const VarIds& jointVarIds)
{
if (runned_ == false) {
runSolver();
}
Factor res (fn->factor());
const BpLinks& links = getLinks( fn);
for (size_t i = 0; i < links.size(); i++) {
Factor msg ({links[i]->varNode()->varId()},
{links[i]->varNode()->range()},
getVarToFactorMsg (links[i]));
res.multiply (msg);
}
res.sumOutAllExcept (jointVarIds);
res.reorderArguments (jointVarIds);
res.normalize();
Params jointDist = res.params();
if (Globals::logDomain) {
Util::exp (jointDist);
}
return jointDist;
}
void
VarElim::processFactorList (const VarIds& vids)
{
totalFactorSize_ = 0;
largestFactorSize_ = 0;
for (size_t i = 0; i < elimOrder_.size(); i++) {
if (Globals::verbosity >= 2) {
if (Globals::verbosity >= 3) {
Util::printDashedLine();
printActiveFactors();
}
cout << "-> summing out " ;
cout << fg.getVarNode (elimOrder_[i])->label() << endl;
}
eliminate (elimOrder_[i]);
}
Factor* finalFactor = new Factor();
for (size_t i = 0; i < factorList_.size(); i++) {
if (factorList_[i]) {
finalFactor->multiply (*factorList_[i]);
delete factorList_[i];
factorList_[i] = 0;
}
}
VarIds unobservedVids;
for (size_t i = 0; i < vids.size(); i++) {
if (fg.getVarNode (vids[i])->hasEvidence() == false) {
unobservedVids.push_back (vids[i]);
}
}
finalFactor->reorderArguments (unobservedVids);
finalFactor->normalize();
factorList_.push_back (finalFactor);
if (Globals::verbosity > 0) {
cout << "total factor size: " << totalFactorSize_ << endl;
cout << "largest factor size: " << largestFactorSize_ << endl;
cout << endl;
}
}
void
BeliefProp::calcFactorToVarMsg (BpLink* link)
{
FacNode* src = link->facNode();
const VarNode* dst = link->varNode();
const BpLinks& links = getLinks (src);
// calculate the product of messages that were sent
// to factor `src', except from var `dst'
unsigned reps = 1;
unsigned msgSize = Util::sizeExpected (src->factor().ranges());
Params msgProduct (msgSize, LogAware::multIdenty());
if (Globals::logDomain) {
for (size_t i = links.size(); i-- > 0; ) {
if (links[i]->varNode() != dst) {
if (Constants::showBpCalcs) {
std::cout << " message from " << links[i]->varNode()->label();
std::cout << ": " ;
}
Util::apply_n_times (msgProduct, getVarToFactorMsg (links[i]),
reps, std::plus<double>());
if (Constants::showBpCalcs) {
std::cout << std::endl;
}
}
reps *= links[i]->varNode()->range();
}
} else {
for (size_t i = links.size(); i-- > 0; ) {
if (links[i]->varNode() != dst) {
if (Constants::showBpCalcs) {
std::cout << " message from " << links[i]->varNode()->label();
std::cout << ": " ;
}
Util::apply_n_times (msgProduct, getVarToFactorMsg (links[i]),
reps, std::multiplies<double>());
if (Constants::showBpCalcs) {
std::cout << std::endl;
}
}
reps *= links[i]->varNode()->range();
}
}
Factor result (src->factor().arguments(),
src->factor().ranges(), msgProduct);
result.multiply (src->factor());
if (Constants::showBpCalcs) {
std::cout << " message product: " << msgProduct << std::endl;
std::cout << " original factor: " << src->factor().params();
std::cout << std::endl;
std::cout << " factor product: " << result.params() << std::endl;
}
result.sumOutAllExcept (dst->varId());
if (Constants::showBpCalcs) {
std::cout << " marginalized: " << result.params() << std::endl;
}
link->nextMessage() = result.params();
LogAware::normalize (link->nextMessage());
if (Constants::showBpCalcs) {
std::cout << " curr msg: " << link->message() << std::endl;
std::cout << " next msg: " << link->nextMessage() << std::endl;
}
}
