131 lines
3.7 KiB
C++
131 lines
3.7 KiB
C++
/*
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* JunctionTree.h
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*
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* Created on: Feb 4, 2010
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* Author: nikai
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* Description: The junction tree
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*/
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#pragma once
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#include <set>
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#include <boost/shared_ptr.hpp>
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#include <boost/function.hpp>
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#include "GaussianConditional.h"
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#include "GaussianFactorGraph.h"
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#include "BayesTree.h"
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namespace gtsam {
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/* ************************************************************************* */
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template <class FG>
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class JunctionTree : public Testable<JunctionTree<FG> > {
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public:
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// the class for subgraphs that also include the pointers to the parents and two children
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class Clique : public FG {
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private:
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typedef typename boost::shared_ptr<Clique> shared_ptr;
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shared_ptr parent_; // the parent subgraph node
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std::vector<shared_ptr> children_; // the child cliques
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Ordering frontal_; // the frontal varaibles
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Unordered separator_; // the separator variables
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friend class JunctionTree<FG>;
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public:
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// empty constructor
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Clique() {}
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// constructor with all the information
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Clique(const FG& fgLocal, const Ordering& frontal, const Unordered& separator,
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const shared_ptr& parent)
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: frontal_(frontal), separator_(separator), FG(fgLocal), parent_(parent) {}
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// constructor for an empty graph
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Clique(const Ordering& frontal, const Unordered& separator, const shared_ptr& parent)
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: frontal_(frontal), separator_(separator), parent_(parent) {}
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// return the members
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const Ordering& frontal() const { return frontal_;}
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const Unordered& separator() const { return separator_;}
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const std::vector<shared_ptr>& children() { return children_; }
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// add a child node
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void addChild(const shared_ptr& child) { children_.push_back(child); }
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// print the object
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void print(const std::string& indent) const;
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void printTree(const std::string& indent) const;
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// check equality
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bool equals(const Clique& other) const;
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};
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// typedef for shared pointers to cliques
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typedef typename Clique::shared_ptr sharedClique;
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protected:
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// Root clique
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sharedClique root_;
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private:
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// distribute the factors along the Bayes tree
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sharedClique distributeFactors(FG& fg, const BayesTree<SymbolicConditional>::sharedClique clique);
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// utility function called by eliminate
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template <class Conditional>
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std::pair<FG, BayesTree<Conditional> > eliminateOneClique(sharedClique fg_);
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public:
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// constructor
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JunctionTree() {}
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// constructor given a factor graph and the elimination ordering
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JunctionTree(FG& fg, const Ordering& ordering);
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// return the root clique
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sharedClique root() const { return root_; }
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// eliminate the factors in the subgraphs
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template <class Conditional>
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BayesTree<Conditional> eliminate();
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// print the object
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void print(const std::string& str) const {
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cout << str << endl;
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if (root_.get()) root_->printTree("");
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}
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/** check equality */
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bool equals(const JunctionTree<FG>& other, double tol = 1e-9) const;
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}; // JunctionTree
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/* ************************************************************************* */
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/**
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* GaussianJunctionTree that does the optimization
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*/
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template <class FG>
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class GaussianJunctionTree: public JunctionTree<FG> {
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public:
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typedef JunctionTree<FG> Base;
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typedef typename JunctionTree<FG>::sharedClique sharedClique;
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protected:
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// back-substitute in topological sort order (parents first)
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void btreeBackSubstitue(typename BayesTree<GaussianConditional>::sharedClique current, VectorConfig& config);
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public :
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GaussianJunctionTree() : Base() {}
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// constructor
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GaussianJunctionTree(FG& fg, const Ordering& ordering) : Base(fg, ordering) {}
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// optimize the linear graph
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VectorConfig optimize();
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}; // GaussianJunctionTree
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} // namespace gtsam
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