gtsam/cpp/FactorGraph.h

157 lines
4.5 KiB
C++

/**
* @file FactorGraph.h
* @brief Factor Graph Base Class
* @author Carlos Nieto
* @author Christian Potthast
*/
// \callgraph
#pragma once
#include <boost/shared_ptr.hpp>
#include <boost/serialization/map.hpp>
#include <boost/serialization/list.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/shared_ptr.hpp>
#include "Testable.h"
#include "BayesNet.h"
namespace gtsam {
class Ordering;
/**
* A factor graph is a bipartite graph with factor nodes connected to variable nodes.
* In this class, however, only factor nodes are kept around.
*
* Templated on the type of factors and configuration.
*/
template<class Factor> class FactorGraph: public Testable<FactorGraph<Factor> > {
public:
typedef typename boost::shared_ptr<Factor> sharedFactor;
typedef typename std::vector<sharedFactor>::iterator iterator;
typedef typename std::vector<sharedFactor>::const_iterator const_iterator;
protected:
/** Collection of factors */
std::vector<sharedFactor> factors_;
/** For each variable a list of factor indices connected to it */
typedef std::map<std::string, std::list<int> > Indices;
Indices indices_;
public:
/** Default constructor */
FactorGraph() {}
/** convert from Bayes net */
template<class Conditional>
FactorGraph(const BayesNet<Conditional>& bayesNet);
/** print out graph */
void print(const std::string& s = "FactorGraph") const;
/** Check equality */
bool equals(const FactorGraph& fg, double tol = 1e-9) const;
/** STL begin and end, so we can use BOOST_FOREACH */
inline iterator begin() { return factors_.begin();}
inline const_iterator begin() const { return factors_.begin();}
inline iterator end() { return factors_.end(); }
inline const_iterator end() const { return factors_.end(); }
/** Get a specific factor by index */
inline sharedFactor operator[](size_t i) const {return factors_[i];}
/** delete factor without re-arranging indexes by inserting a NULL pointer */
inline void remove(size_t i) { factors_[i].reset();}
/** return the number of factors and NULLS */
inline size_t size() const { return factors_.size();}
/** return the number valid factors */
size_t nrFactors() const;
/** Add a factor */
void push_back(sharedFactor factor);
/** push back many factors */
void push_back(const FactorGraph<Factor>& factors);
/** replace a factor by index */
void replace(int index, sharedFactor factor);
/** return keys in some random order */
Ordering keys() const;
/** Check whether a factor with this variable exists */
bool involves(const std::string& key) const {
return !(indices_.find(key)==indices_.end());
}
/**
* Compute colamd ordering
*/
Ordering getOrdering() const;
/**
* shared pointer versions for MATLAB
*/
boost::shared_ptr<Ordering> getOrdering_() const;
/**
* Return indices for all factors that involve the given node
* @param key the key for the given node
*/
std::list<int> factors(const std::string& key) const;
/**
* find all the factors that involve the given node and remove them
* from the factor graph
* @param key the key for the given node
*/
std::vector<sharedFactor> findAndRemoveFactors(const std::string& key);
/**
* find the minimum spanning tree
*/
std::vector<std::pair<std::string, std::string> > findMinimumSpanningTree() const;
private:
/** Associate factor index with the variables connected to the factor */
void associateFactor(int index, sharedFactor factor);
/** Serialization function */
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version) {
ar & BOOST_SERIALIZATION_NVP(factors_);
ar & BOOST_SERIALIZATION_NVP(indices_);
}
}; // FactorGraph
/**
* Extract and combine all the factors that involve a given node
* Put this here as not all Factors have a combine constructor
* @param key the key for the given node
* @return the combined linear factor
*/
template<class Factor> boost::shared_ptr<Factor>
removeAndCombineFactors(FactorGraph<Factor>& factorGraph, const std::string& key);
/**
* static function that combines two factor graphs
* @param const &fg1 Linear factor graph
* @param const &fg2 Linear factor graph
* @return a new combined factor graph
*/
template<class Factor>
FactorGraph<Factor> combine(const FactorGraph<Factor>& fg1, const FactorGraph<Factor>& fg2);
} // namespace gtsam