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yap-6.3/packages/CLPBN/clpbn/bp/SPSolver.cpp
2011-07-25 17:09:43 +01:00

471 lines
12 KiB
C++

#include <cassert>
#include <limits>
#include <iostream>
#include "SPSolver.h"
#include "FactorGraph.h"
#include "FgVarNode.h"
#include "Factor.h"
#include "Shared.h"
SPSolver::SPSolver (FactorGraph& fg) : Solver (&fg)
{
fg_ = &fg;
}
SPSolver::~SPSolver (void)
{
for (unsigned i = 0; i < varsI_.size(); i++) {
delete varsI_[i];
}
for (unsigned i = 0; i < factorsI_.size(); i++) {
delete factorsI_[i];
}
for (unsigned i = 0; i < links_.size(); i++) {
delete links_[i];
}
}
void
SPSolver::runTreeSolver (void)
{
CFactorSet factors = fg_->getFactors();
bool finish = false;
while (!finish) {
finish = true;
for (unsigned i = 0; i < factors.size(); i++) {
CLinkSet links = factorsI_[factors[i]->getIndex()]->getLinks();
for (unsigned j = 0; j < links.size(); j++) {
if (!links[j]->messageWasSended()) {
if (readyToSendMessage(links[j])) {
links[j]->setNextMessage (getFactor2VarMsg (links[j]));
links[j]->updateMessage();
}
finish = false;
}
}
}
}
}
bool
SPSolver::readyToSendMessage (const Link* link) const
{
CFgVarSet factorVars = link->getFactor()->getFgVarNodes();
for (unsigned i = 0; i < factorVars.size(); i++) {
if (factorVars[i] != link->getVariable()) {
CLinkSet links = varsI_[factorVars[i]->getIndex()]->getLinks();
for (unsigned j = 0; j < links.size(); j++) {
if (links[j]->getFactor() != link->getFactor() &&
!links[j]->messageWasSended()) {
return false;
}
}
}
}
return true;
}
void
SPSolver::runSolver (void)
{
initializeSolver();
runTreeSolver();
return;
nIter_ = 0;
while (!converged() && nIter_ < SolverOptions::maxIter) {
nIter_ ++;
if (DL >= 2) {
cout << endl;
cout << "****************************************" ;
cout << "****************************************" ;
cout << endl;
cout << " Iteration " << nIter_ << endl;
cout << "****************************************" ;
cout << "****************************************" ;
cout << endl;
}
switch (SolverOptions::schedule) {
case SolverOptions::S_SEQ_RANDOM:
random_shuffle (links_.begin(), links_.end());
// no break
case SolverOptions::S_SEQ_FIXED:
for (unsigned i = 0; i < links_.size(); i++) {
links_[i]->setNextMessage (getFactor2VarMsg (links_[i]));
links_[i]->updateMessage();
}
break;
case SolverOptions::S_PARALLEL:
for (unsigned i = 0; i < links_.size(); i++) {
links_[i]->setNextMessage (getFactor2VarMsg (links_[i]));
}
for (unsigned i = 0; i < links_.size(); i++) {
links_[i]->updateMessage();
}
break;
case SolverOptions::S_MAX_RESIDUAL:
maxResidualSchedule();
break;
}
}
if (DL >= 2) {
cout << endl;
if (nIter_ < SolverOptions::maxIter) {
cout << "Loopy Sum-Product converged in " ;
cout << nIter_ << " iterations" << endl;
} else {
cout << "The maximum number of iterations was hit, terminating..." ;
cout << endl;
}
}
}
ParamSet
SPSolver::getPosterioriOf (Vid vid) const
{
assert (fg_->getFgVarNode (vid));
FgVarNode* var = fg_->getFgVarNode (vid);
ParamSet probs;
if (var->hasEvidence()) {
probs.resize (var->getDomainSize(), 0.0);
probs[var->getEvidence()] = 1.0;
} else {
probs.resize (var->getDomainSize(), 1.0);
CLinkSet links = varsI_[var->getIndex()]->getLinks();
for (unsigned i = 0; i < links.size(); i++) {
CParamSet msg = links[i]->getMessage();
for (unsigned j = 0; j < msg.size(); j++) {
probs[j] *= msg[j];
}
}
Util::normalize (probs);
}
return probs;
}
ParamSet
SPSolver::getJointDistributionOf (const VidSet& jointVids)
{
FgVarSet jointVars;
unsigned dsize = 1;
for (unsigned i = 0; i < jointVids.size(); i++) {
FgVarNode* varNode = fg_->getFgVarNode (jointVids[i]);
dsize *= varNode->getDomainSize();
jointVars.push_back (varNode);
}
unsigned maxVid = std::numeric_limits<unsigned>::max();
FgVarNode* junctionVar = new FgVarNode (maxVid, dsize);
FgVarSet factorVars = { junctionVar };
for (unsigned i = 0; i < jointVars.size(); i++) {
factorVars.push_back (jointVars[i]);
}
unsigned nParams = dsize * dsize;
ParamSet params (nParams);
for (unsigned i = 0; i < nParams; i++) {
unsigned row = i / dsize;
unsigned col = i % dsize;
if (row == col) {
params[i] = 1;
} else {
params[i] = 0;
}
}
Distribution* dist = new Distribution (params, maxVid);
Factor* newFactor = new Factor (factorVars, dist);
fg_->addVariable (junctionVar);
fg_->addFactor (newFactor);
runSolver();
ParamSet results = getPosterioriOf (maxVid);
deleteJunction (newFactor, junctionVar);
return results;
}
void
SPSolver::initializeSolver (void)
{
fg_->setIndexes();
CFgVarSet vars = fg_->getFgVarNodes();
for (unsigned i = 0; i < varsI_.size(); i++) {
delete varsI_[i];
}
varsI_.reserve (vars.size());
for (unsigned i = 0; i < vars.size(); i++) {
varsI_.push_back (new SPNodeInfo());
}
CFactorSet factors = fg_->getFactors();
for (unsigned i = 0; i < factorsI_.size(); i++) {
delete factorsI_[i];
}
factorsI_.reserve (factors.size());
for (unsigned i = 0; i < factors.size(); i++) {
factorsI_.push_back (new SPNodeInfo());
}
for (unsigned i = 0; i < links_.size(); i++) {
delete links_[i];
}
createLinks();
for (unsigned i = 0; i < links_.size(); i++) {
Factor* source = links_[i]->getFactor();
FgVarNode* dest = links_[i]->getVariable();
varsI_[dest->getIndex()]->addLink (links_[i]);
factorsI_[source->getIndex()]->addLink (links_[i]);
}
}
void
SPSolver::createLinks (void)
{
CFactorSet factors = fg_->getFactors();
for (unsigned i = 0; i < factors.size(); i++) {
CFgVarSet neighbors = factors[i]->getFgVarNodes();
for (unsigned j = 0; j < neighbors.size(); j++) {
links_.push_back (new Link (factors[i], neighbors[j]));
}
}
}
void
SPSolver::deleteJunction (Factor* f, FgVarNode* v)
{
fg_->removeFactor (f);
f->freeDistribution();
delete f;
fg_->removeVariable (v);
delete v;
}
bool
SPSolver::converged (void)
{
// this can happen if the graph is fully disconnected
if (links_.size() == 0) {
return true;
}
if (nIter_ == 0 || nIter_ == 1) {
return false;
}
bool converged = true;
if (SolverOptions::schedule == SolverOptions::S_MAX_RESIDUAL) {
Param maxResidual = (*(sortedOrder_.begin()))->getResidual();
if (maxResidual < SolverOptions::accuracy) {
converged = true;
} else {
converged = false;
}
} else {
for (unsigned i = 0; i < links_.size(); i++) {
double residual = links_[i]->getResidual();
if (DL >= 2) {
cout << links_[i]->toString() + " residual = " << residual << endl;
}
if (residual > SolverOptions::accuracy) {
converged = false;
if (DL == 0) break;
}
}
}
return converged;
}
void
SPSolver::maxResidualSchedule (void)
{
if (nIter_ == 1) {
for (unsigned i = 0; i < links_.size(); i++) {
links_[i]->setNextMessage (getFactor2VarMsg (links_[i]));
SortedOrder::iterator it = sortedOrder_.insert (links_[i]);
linkMap_.insert (make_pair (links_[i], it));
if (DL >= 2 && DL < 5) {
cout << "calculating " << links_[i]->toString() << endl;
}
}
return;
}
for (unsigned c = 0; c < links_.size(); c++) {
if (DL >= 2) {
cout << endl << "current residuals:" << endl;
for (SortedOrder::iterator it = sortedOrder_.begin();
it != sortedOrder_.end(); it ++) {
cout << " " << setw (30) << left << (*it)->toString();
cout << "residual = " << (*it)->getResidual() << endl;
}
}
SortedOrder::iterator it = sortedOrder_.begin();
Link* link = *it;
if (DL >= 2) {
cout << "updating " << (*sortedOrder_.begin())->toString() << endl;
}
if (link->getResidual() < SolverOptions::accuracy) {
return;
}
link->updateMessage();
link->clearResidual();
sortedOrder_.erase (it);
linkMap_.find (link)->second = sortedOrder_.insert (link);
// update the messages that depend on message source --> destin
CFactorSet factorNeighbors = link->getVariable()->getFactors();
for (unsigned i = 0; i < factorNeighbors.size(); i++) {
if (factorNeighbors[i] != link->getFactor()) {
CLinkSet links = factorsI_[factorNeighbors[i]->getIndex()]->getLinks();
for (unsigned j = 0; j < links.size(); j++) {
if (links[j]->getVariable() != link->getVariable()) {
if (DL >= 2 && DL < 5) {
cout << " calculating " << links[j]->toString() << endl;
}
links[j]->setNextMessage (getFactor2VarMsg (links[j]));
LinkMap::iterator iter = linkMap_.find (links[j]);
sortedOrder_.erase (iter->second);
iter->second = sortedOrder_.insert (links[j]);
}
}
}
}
}
}
ParamSet
SPSolver::getFactor2VarMsg (const Link* link) const
{
const Factor* src = link->getFactor();
const FgVarNode* dest = link->getVariable();
CFgVarSet neighbors = src->getFgVarNodes();
CLinkSet links = factorsI_[src->getIndex()]->getLinks();
// calculate the product of messages that were sent
// to factor `src', except from var `dest'
Factor result (*src);
Factor temp;
if (DL >= 5) {
cout << "calculating " ;
cout << src->getLabel() << " --> " << dest->getLabel();
cout << endl;
}
for (unsigned i = 0; i < neighbors.size(); i++) {
if (links[i]->getVariable() != dest) {
if (DL >= 5) {
cout << " message from " << links[i]->getVariable()->getLabel();
cout << ": " ;
ParamSet p = getVar2FactorMsg (links[i]);
cout << endl;
Factor temp2 (links[i]->getVariable(), p);
temp.multiplyByFactor (temp2);
temp2.freeDistribution();
} else {
Factor temp2 (links[i]->getVariable(), getVar2FactorMsg (links[i]));
temp.multiplyByFactor (temp2);
temp2.freeDistribution();
}
}
}
if (links.size() >= 2) {
result.multiplyByFactor (temp, &(src->getCptEntries()));
if (DL >= 5) {
cout << " message product: " ;
cout << Util::parametersToString (temp.getParameters()) << endl;
cout << " factor product: " ;
cout << Util::parametersToString (src->getParameters());
cout << " x " ;
cout << Util::parametersToString (temp.getParameters());
cout << " = " ;
cout << Util::parametersToString (result.getParameters()) << endl;
}
temp.freeDistribution();
}
for (unsigned i = 0; i < links.size(); i++) {
if (links[i]->getVariable() != dest) {
result.removeVariable (links[i]->getVariable());
}
}
if (DL >= 5) {
cout << " final message: " ;
cout << Util::parametersToString (result.getParameters()) << endl << endl;
}
ParamSet msg = result.getParameters();
result.freeDistribution();
return msg;
}
ParamSet
SPSolver::getVar2FactorMsg (const Link* link) const
{
const FgVarNode* src = link->getVariable();
const Factor* dest = link->getFactor();
ParamSet msg;
if (src->hasEvidence()) {
msg.resize (src->getDomainSize(), 0.0);
msg[src->getEvidence()] = 1.0;
if (DL >= 5) {
cout << Util::parametersToString (msg);
}
} else {
msg.resize (src->getDomainSize(), 1.0);
}
if (DL >= 5) {
cout << Util::parametersToString (msg);
}
CLinkSet links = varsI_[src->getIndex()]->getLinks();
for (unsigned i = 0; i < links.size(); i++) {
if (links[i]->getFactor() != dest) {
CParamSet msgFromFactor = links[i]->getMessage();
for (unsigned j = 0; j < msgFromFactor.size(); j++) {
msg[j] *= msgFromFactor[j];
}
if (DL >= 5) {
cout << " x " << Util::parametersToString (msgFromFactor);
}
}
}
if (DL >= 5) {
cout << " = " << Util::parametersToString (msg);
}
return msg;
}