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