gtsam/gtsam/inference/ClusterTree.h

126 lines
4.0 KiB
C++

/**
* @file ClusterTree.h
* @date Oct 8, 2013
* @author Kai Ni
* @author Richard Roberts
* @author Frank Dellaert
* @brief Collects factorgraph fragments defined on variable clusters, arranged in a tree
*/
#pragma once
#include <gtsam/base/Testable.h>
#include <gtsam/base/FastVector.h>
#include <gtsam/inference/Ordering.h>
namespace gtsam
{
/**
* A cluster-tree is associated with a factor graph and is defined as in Koller-Friedman:
* each node k represents a subset \f$ C_k \sub X \f$, and the tree is family preserving, in that
* each factor \f$ f_i \f$ is associated with a single cluster and \f$ scope(f_i) \sub C_k \f$.
* \nosubgrouping
*/
template<class BAYESTREE, class GRAPH>
class ClusterTree
{
public:
typedef GRAPH FactorGraphType; ///< The factor graph type
typedef typename GRAPH::FactorType FactorType; ///< The type of factors
typedef ClusterTree<BAYESTREE, GRAPH> This; ///< This class
typedef boost::shared_ptr<This> shared_ptr; ///< Shared pointer to this class
typedef boost::shared_ptr<FactorType> sharedFactor; ///< Shared pointer to a factor
typedef BAYESTREE BayesTreeType; ///< The BayesTree type produced by elimination
typedef typename BayesTreeType::ConditionalType ConditionalType; ///< The type of conditionals
typedef boost::shared_ptr<ConditionalType> sharedConditional; ///< Shared pointer to a conditional
typedef typename FactorGraphType::Eliminate Eliminate; ///< Typedef for an eliminate subroutine
struct Cluster {
typedef Ordering Keys;
typedef FastVector<sharedFactor> Factors;
typedef FastVector<boost::shared_ptr<Cluster> > Children;
Keys orderedFrontalKeys; ///< Frontal keys of this node
Factors factors; ///< Factors associated with this node
Children children; ///< sub-trees
int problemSize_;
int problemSize() const { return problemSize_; }
/** print this node */
void print(const std::string& s = "", const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
};
typedef boost::shared_ptr<Cluster> sharedCluster; ///< Shared pointer to Cluster
typedef Cluster Node; ///< Define Node=Cluster for compatibility with tree traversal functions
typedef sharedCluster sharedNode; ///< Define Node=Cluster for compatibility with tree traversal functions
/** concept check */
GTSAM_CONCEPT_TESTABLE_TYPE(FactorType);
protected:
FastVector<sharedNode> roots_;
FastVector<sharedFactor> remainingFactors_;
/// @name Standard Constructors
/// @{
/** Copy constructor - makes a deep copy of the tree structure, but only pointers to factors are
* copied, factors are not cloned. */
ClusterTree(const This& other) { *this = other; }
/// @}
public:
/// @name Testable
/// @{
/** Print the cluster tree */
void print(const std::string& s = "", const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
/// @}
/// @name Standard Interface
/// @{
/** Eliminate the factors to a Bayes tree and remaining factor graph
* @param function The function to use to eliminate, see the namespace functions
* in GaussianFactorGraph.h
* @return The Bayes tree and factor graph resulting from elimination
*/
std::pair<boost::shared_ptr<BayesTreeType>, boost::shared_ptr<FactorGraphType> >
eliminate(const Eliminate& function) const;
/// @}
/// @name Advanced Interface
/// @{
/** Return the set of roots (one for a tree, multiple for a forest) */
const FastVector<sharedNode>& roots() const { return roots_; }
/** Return the remaining factors that are not pulled into elimination */
const FastVector<sharedFactor>& remainingFactors() const { return remainingFactors_; }
/// @}
protected:
/// @name Details
/// Assignment operator - makes a deep copy of the tree structure, but only pointers to factors
/// are copied, factors are not cloned.
This& operator=(const This& other);
/// Default constructor to be used in derived classes
ClusterTree() {}
/// @}
};
}