80 lines
2.2 KiB
C++
80 lines
2.2 KiB
C++
/* ----------------------------------------------------------------------------
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* GTSAM Copyright 2010, Georgia Tech Research Corporation,
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* Atlanta, Georgia 30332-0415
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* All Rights Reserved
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* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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* See LICENSE for the license information
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* -------------------------------------------------------------------------- */
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/**
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* @file DSFVector.h
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* @date Jun 25, 2010
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* @author Kai Ni
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* @brief A faster implementation for DSF, which uses vector rather than btree. As a result, the size of the forest is prefixed.
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*/
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#pragma once
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#include <vector>
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#include <map>
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#include <set>
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#include <boost/shared_ptr.hpp>
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namespace gtsam {
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/**
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* A fast implementation of disjoint set forests that uses vector as underly data structure.
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* @addtogroup base
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*/
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class DSFVector {
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public:
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typedef std::vector<size_t> V; ///< Vector of ints
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typedef size_t Label; ///< Label type
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typedef V::const_iterator const_iterator; ///< const iterator over V
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typedef V::iterator iterator;///< iterator over V
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private:
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// TODO could use existing memory to improve the efficiency
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boost::shared_ptr<V> v_;
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std::vector<size_t> keys_;
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public:
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/// constructor that allocate a new memory
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DSFVector(const size_t numNodes);
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/// constructor that uses the existing memory
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DSFVector(const boost::shared_ptr<V>& v_in, const std::vector<size_t>& keys);
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/// find the label of the set in which {key} lives
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inline Label findSet(size_t key) const {
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size_t parent = (*v_)[key];
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while (parent != key) {
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key = parent;
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parent = (*v_)[key];
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}
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return parent;
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}
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/// find whether there is one and only one occurrence for the given {label}
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bool isSingleton(const Label& label) const;
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/// get the nodes in the tree with the given label
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std::set<size_t> set(const Label& label) const;
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/// return all sets, i.e. a partition of all elements
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std::map<Label, std::set<size_t> > sets() const;
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/// return all sets, i.e. a partition of all elements
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std::map<Label, std::vector<size_t> > arrays() const;
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/// the in-place version of makeUnion
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void makeUnionInPlace(const size_t& i1, const size_t& i2);
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};
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}
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