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
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;
}
}
