gtsam/inference/BinaryConditional.h

116 lines
3.0 KiB
C++

/**
* @file DiscreteConditional.h
* @brief Discrete Conditional node for use in Bayes nets
* @author Manohar Paluri
*/
// \callgraph
#pragma once
#include <list>
#include <string>
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <boost/foreach.hpp> // TODO: make cpp file
#include <boost/serialization/list.hpp>
#include <boost/serialization/vector.hpp>
#include <gtsam/inference/Conditional.h>
#include <gtsam/inference/Key.h>
#include <gtsam/inference/SymbolMap.h>
namespace gtsam {
/**
* Conditional node for use in a Bayes net
*/
class BinaryConditional: public Conditional {
private:
std::list<Symbol> parents_;
std::vector<double> cpt_;
public:
/** convenience typename for a shared pointer to this class */
typedef boost::shared_ptr<BinaryConditional> shared_ptr;
/**
* Empty Constructor to make serialization possible
*/
BinaryConditional(){}
/**
* No parents
*/
BinaryConditional(const Symbol& key, double p) :
Conditional(key) {
cpt_.push_back(1-p);
cpt_.push_back(p);
}
/**
* Single parent
*/
BinaryConditional(const Symbol& key, const Symbol& parent, const std::vector<double>& cpt) :
Conditional(key) {
parents_.push_back(parent);
for( size_t i = 0 ; i < cpt.size() ; i++ )
cpt_.push_back(1-cpt[i]); // p(!x|parents)
cpt_.insert(cpt_.end(),cpt.begin(),cpt.end()); // p(x|parents)
}
double probability( SymbolMap<bool> config) {
int index = 0, count = 1;
BOOST_FOREACH(const Symbol& parent, parents_){
index += count*(int)(config[parent]);
count = count << 1;
}
if( config.at(key_) )
index += count;
return cpt_[index];
}
/** print */
void print(const std::string& s = "BinaryConditional") const {
std::cout << s << " P(" << (std::string)key_;
if (parents_.size()>0) std::cout << " |";
BOOST_FOREACH(std::string parent, parents_) std::cout << " " << parent;
std::cout << ")" << std::endl;
std::cout << "Conditional Probability Table::" << std::endl;
BOOST_FOREACH(double p, cpt_) std::cout << p << "\t";
std::cout<< std::endl;
}
/** check equality */
bool equals(const Conditional& c, double tol = 1e-9) const {
if (!Conditional::equals(c)) return false;
const BinaryConditional* p = dynamic_cast<const BinaryConditional*> (&c);
if (p == NULL) return false;
return (parents_ == p->parents_ && cpt_ == p->cpt_);
}
/** return parents */
std::list<Symbol> parents() const { return parents_;}
/** return Conditional probability table*/
std::vector<double> cpt() const { return cpt_;}
/** find the number of parents */
size_t nrParents() const {
return parents_.size();
}
private:
/** Serialization function */
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version) {
ar & boost::serialization::make_nvp("Conditional", boost::serialization::base_object<Conditional>(*this));
ar & BOOST_SERIALIZATION_NVP(parents_);
ar & BOOST_SERIALIZATION_NVP(cpt_);
}
};
} /// namespace gtsam