66 lines
1.5 KiB
C++
66 lines
1.5 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 DSFMap.h
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* @date Oct 26, 2013
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* @author Frank Dellaert
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* @brief Allow for arbitrary type in DSF
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*/
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#pragma once
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#include <map>
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namespace gtsam {
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/**
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* Disjoint set forest using an STL map data structure underneath
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* Uses rank compression but not union by rank :-(
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* @addtogroup base
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*/
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template<class KEY>
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class DSFMap {
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/// We store the forest in an STL map
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typedef std::map<KEY, KEY> Map;
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mutable Map parent_;
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public:
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/// constructor
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DSFMap() {}
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/// find the label of the set in which {key} lives
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KEY find(const KEY& key) const {
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typename Map::const_iterator it = parent_.find(key);
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// if key does not exist, create and return itself
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if (it==parent_.end()) {
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parent_[key] = key;
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return key;
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} else {
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// follow parent pointers until we reach set representative
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KEY parent = it->second;
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if (parent != key)
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parent = find(parent); // not yet, recurse!
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parent_[key] = parent; // path compression
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return parent;
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}
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}
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/// Merge two sets
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void merge(const KEY& i1, const KEY& i2) {
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parent_[find(i2)] = find(i1);
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}
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};
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}
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