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yap-6.3/packages/CLPBN/clpbn/bp/SPSolver.h
2011-05-17 12:00:33 +01:00

172 lines
4.2 KiB
C++
Executable File

#ifndef BP_SPSOLVER_H
#define BP_SPSOLVER_H
#include <cmath>
#include <map>
#include <vector>
#include <string>
#include "Solver.h"
#include "FgVarNode.h"
#include "Factor.h"
using namespace std;
class FactorGraph;
class SPSolver;
struct Link
{
Link (Factor* s, FgVarNode* d)
{
source = s;
destination = d;
}
string toString (void) const
{
stringstream ss;
ss << source->getLabel() << " --> " ;
ss << destination->getLabel();
return ss.str();
}
Factor* source;
FgVarNode* destination;
static SPSolver* klass;
};
class MessageBanket
{
public:
MessageBanket (const FgVarNode* var)
{
vector<Factor*> sources = var->getFactors();
for (unsigned i = 0; i < sources.size(); i++) {
indexMap_.insert (make_pair (sources[i], i));
currMsgs_.push_back (Message(var->getDomainSize(), 1));
nextMsgs_.push_back (Message(var->getDomainSize(), -10));
residuals_.push_back (0.0);
}
}
void updateMessage (const Factor* source)
{
unsigned idx = getIndex(source);
currMsgs_[idx] = nextMsgs_[idx];
}
void setNextMessage (const Factor* source, const Message& msg)
{
unsigned idx = getIndex(source);
nextMsgs_[idx] = msg;
residuals_[idx] = computeResidual (source);
}
const Message& getMessage (const Factor* source) const
{
return currMsgs_[getIndex(source)];
}
double getResidual (const Factor* source) const
{
return residuals_[getIndex(source)];
}
void resetResidual (const Factor* source)
{
residuals_[getIndex(source)] = 0.0;
}
private:
double computeResidual (const Factor* source)
{
double change = 0.0;
unsigned idx = getIndex (source);
const Message& currMessage = currMsgs_[idx];
const Message& nextMessage = nextMsgs_[idx];
for (unsigned i = 0; i < currMessage.size(); i++) {
change += abs (currMessage[i] - nextMessage[i]);
}
return change;
}
unsigned getIndex (const Factor* factor) const
{
assert (factor);
assert (indexMap_.find(factor) != indexMap_.end());
return indexMap_.find(factor)->second;
}
typedef map<const Factor*, unsigned> IndexMap;
IndexMap indexMap_;
vector<Message> currMsgs_;
vector<Message> nextMsgs_;
vector<double> residuals_;
};
class SPSolver : public Solver
{
public:
SPSolver (const FactorGraph&);
~SPSolver (void);
void runSolver (void);
ParamSet getPosterioriOf (const Variable* var) const;
private:
bool converged (void);
void maxResidualSchedule (void);
void updateMessage (const Link&);
void updateMessage (const Factor*, const FgVarNode*);
void calculateNextMessage (const Link&);
void calculateNextMessage (const Factor*, const FgVarNode*);
void calculateVarFactorMessage (
const FgVarNode*, const Factor*, Message&) const;
double getResidual (const Link&) const;
void resetResidual (const Link&) const;
friend bool compareResidual (const Link&, const Link&);
const FactorGraph* fg_;
vector<MessageBanket*> msgs_;
Schedule schedule_;
int nIter_;
double accuracy_;
int maxIter_;
vector<Link> updateOrder_;
};
inline double
SPSolver::getResidual (const Link& link) const
{
MessageBanket* mb = Link::klass->msgs_[link.destination->getIndex()];
return mb->getResidual (link.source);
}
inline void
SPSolver::resetResidual (const Link& link) const
{
MessageBanket* mb = Link::klass->msgs_[link.destination->getIndex()];
mb->resetResidual (link.source);
}
inline bool
compareResidual (const Link& link1, const Link& link2)
{
MessageBanket* mb1 = Link::klass->msgs_[link1.destination->getIndex()];
MessageBanket* mb2 = Link::klass->msgs_[link2.destination->getIndex()];
return mb1->getResidual(link1.source) > mb2->getResidual(link2.source);
}
#endif