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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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*
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* This file is a part of LEMON, a generic C++ optimization library.
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*
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* Copyright (C) 2003-2009
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* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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* (Egervary Research Group on Combinatorial Optimization, EGRES).
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*
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* Permission to use, modify and distribute this software is granted
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* provided that this copyright notice appears in all copies. For
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* precise terms see the accompanying LICENSE file.
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*
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* This software is provided "AS IS" with no warranty of any kind,
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* express or implied, and with no claim as to its suitability for any
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* purpose.
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*
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*/
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#ifndef LEMON_MAX_MATCHING_H
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#define LEMON_MAX_MATCHING_H
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#include <vector>
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#include <queue>
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#include <set>
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#include <limits>
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#include <lemon/core.h>
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#include <lemon/unionfind.h>
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#include <lemon/bin_heap.h>
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#include <lemon/maps.h>
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///\ingroup matching
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///\file
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///\brief Maximum matching algorithms in general graphs.
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namespace lemon {
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/// \ingroup matching
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///
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/// \brief Edmonds' alternating forest maximum matching algorithm.
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/// \brief Maximum cardinality matching in general graphs
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///
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/// This class implements Edmonds' alternating forest matching
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/// algorithm. The algorithm can be started from an arbitrary initial
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/// matching (the default is the empty one)
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/// This class implements Edmonds' alternating forest matching algorithm
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/// for finding a maximum cardinality matching in a general graph.
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/// It can be started from an arbitrary initial matching
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/// (the default is the empty one).
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///
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/// The dual solution of the problem is a map of the nodes to
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/// MaxMatching::Status, having values \c EVEN/D, \c ODD/A and \c
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/// MATCHED/C showing the Gallai-Edmonds decomposition of the
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/// graph. The nodes in \c EVEN/D induce a graph with
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/// factor-critical components, the nodes in \c ODD/A form the
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/// barrier, and the nodes in \c MATCHED/C induce a graph having a
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/// perfect matching. The number of the factor-critical components
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/// \ref MaxMatching::Status "Status", having values \c EVEN (or \c D),
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/// \c ODD (or \c A) and \c MATCHED (or \c C) defining the Gallai-Edmonds
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/// decomposition of the graph. The nodes in \c EVEN/D induce a subgraph
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/// with factor-critical components, the nodes in \c ODD/A form the
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/// canonical barrier, and the nodes in \c MATCHED/C induce a graph having
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/// a perfect matching. The number of the factor-critical components
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/// minus the number of barrier nodes is a lower bound on the
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/// unmatched nodes, and the matching is optimal if and only if this bound is
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/// tight. This decomposition can be attained by calling \c
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/// tight. This decomposition can be obtained by calling \c
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/// decomposition() after running the algorithm.
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///
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/// \param GR The graph type the algorithm runs on.
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/// \tparam GR The graph type the algorithm runs on.
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template <typename GR>
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class MaxMatching {
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public:
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/// The graph type of the algorithm
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typedef GR Graph;
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typedef typename Graph::template NodeMap<typename Graph::Arc>
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MatchingMap;
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68 |
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///\brief Indicates the Gallai-Edmonds decomposition of the graph.
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///\brief Status constants for Gallai-Edmonds decomposition.
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///
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///Indicates the Gallai-Edmonds decomposition of the graph. The
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///nodes with Status \c EVEN/D induce a graph with factor-critical
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///components, the nodes in \c ODD/A form the canonical barrier,
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///and the nodes in \c MATCHED/C induce a graph having a perfect
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///matching.
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///These constants are used for indicating the Gallai-Edmonds
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///decomposition of a graph. The nodes with status \c EVEN (or \c D)
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///induce a subgraph with factor-critical components, the nodes with
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///status \c ODD (or \c A) form the canonical barrier, and the nodes
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///with status \c MATCHED (or \c C) induce a subgraph having a
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///perfect matching.
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enum Status {
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EVEN = 1, D = 1, MATCHED = 0, C = 0, ODD = -1, A = -1, UNMATCHED = -2
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EVEN = 1, ///< = 1. (\c D is an alias for \c EVEN.)
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D = 1,
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MATCHED = 0, ///< = 0. (\c C is an alias for \c MATCHED.)
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C = 0,
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ODD = -1, ///< = -1. (\c A is an alias for \c ODD.)
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A = -1,
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UNMATCHED = -2 ///< = -2.
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};
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typedef typename Graph::template NodeMap<Status> StatusMap;
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private:
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TEMPLATE_GRAPH_TYPEDEFS(Graph);
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typedef UnionFindEnum<IntNodeMap> BlossomSet;
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typedef ExtendFindEnum<IntNodeMap> TreeSet;
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typedef RangeMap<Node> NodeIntMap;
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typedef MatchingMap EarMap;
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typedef std::vector<Node> NodeQueue;
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const Graph& _graph;
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MatchingMap* _matching;
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StatusMap* _status;
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EarMap* _ear;
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IntNodeMap* _blossom_set_index;
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BlossomSet* _blossom_set;
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NodeIntMap* _blossom_rep;
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IntNodeMap* _tree_set_index;
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TreeSet* _tree_set;
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NodeQueue _node_queue;
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int _process, _postpone, _last;
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int _node_num;
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private:
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void createStructures() {
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_node_num = countNodes(_graph);
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if (!_matching) {
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_matching = new MatchingMap(_graph);
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}
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if (!_status) {
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_status = new StatusMap(_graph);
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}
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if (!_ear) {
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_ear = new EarMap(_graph);
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}
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if (!_blossom_set) {
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_blossom_set_index = new IntNodeMap(_graph);
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_blossom_set = new BlossomSet(*_blossom_set_index);
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}
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if (!_blossom_rep) {
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_blossom_rep = new NodeIntMap(_node_num);
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}
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if (!_tree_set) {
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_tree_set_index = new IntNodeMap(_graph);
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_tree_set = new TreeSet(*_tree_set_index);
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}
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_node_queue.resize(_node_num);
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}
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void destroyStructures() {
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if (_matching) {
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delete _matching;
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}
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if (_status) {
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delete _status;
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}
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if (_ear) {
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delete _ear;
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}
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if (_blossom_set) {
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delete _blossom_set;
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delete _blossom_set_index;
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}
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if (_blossom_rep) {
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delete _blossom_rep;
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}
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if (_tree_set) {
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delete _tree_set_index;
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delete _tree_set;
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}
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}
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void processDense(const Node& n) {
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_process = _postpone = _last = 0;
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_node_queue[_last++] = n;
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while (_process != _last) {
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Node u = _node_queue[_process++];
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for (OutArcIt a(_graph, u); a != INVALID; ++a) {
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Node v = _graph.target(a);
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if ((*_status)[v] == MATCHED) {
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extendOnArc(a);
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} else if ((*_status)[v] == UNMATCHED) {
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augmentOnArc(a);
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return;
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}
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}
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}
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while (_postpone != _last) {
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Node u = _node_queue[_postpone++];
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for (OutArcIt a(_graph, u); a != INVALID ; ++a) {
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Node v = _graph.target(a);
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if ((*_status)[v] == EVEN) {
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if (_blossom_set->find(u) != _blossom_set->find(v)) {
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shrinkOnEdge(a);
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}
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}
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while (_process != _last) {
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Node w = _node_queue[_process++];
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for (OutArcIt b(_graph, w); b != INVALID; ++b) {
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Node x = _graph.target(b);
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if ((*_status)[x] == MATCHED) {
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extendOnArc(b);
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} else if ((*_status)[x] == UNMATCHED) {
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augmentOnArc(b);
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return;
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}
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}
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}
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}
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}
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}
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void processSparse(const Node& n) {
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_process = _last = 0;
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_node_queue[_last++] = n;
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while (_process != _last) {
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Node u = _node_queue[_process++];
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for (OutArcIt a(_graph, u); a != INVALID; ++a) {
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Node v = _graph.target(a);
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if ((*_status)[v] == EVEN) {
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if (_blossom_set->find(u) != _blossom_set->find(v)) {
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shrinkOnEdge(a);
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}
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} else if ((*_status)[v] == MATCHED) {
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extendOnArc(a);
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} else if ((*_status)[v] == UNMATCHED) {
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augmentOnArc(a);
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return;
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}
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}
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}
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}
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void shrinkOnEdge(const Edge& e) {
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Node nca = INVALID;
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{
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std::set<Node> left_set, right_set;
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Node left = (*_blossom_rep)[_blossom_set->find(_graph.u(e))];
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left_set.insert(left);
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Node right = (*_blossom_rep)[_blossom_set->find(_graph.v(e))];
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right_set.insert(right);
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while (true) {
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if ((*_matching)[left] == INVALID) break;
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left = _graph.target((*_matching)[left]);
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240 |
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left = (*_blossom_rep)[_blossom_set->
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find(_graph.target((*_ear)[left]))];
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if (right_set.find(left) != right_set.end()) {
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nca = left;
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break;
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245 |
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}
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246 |
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left_set.insert(left);
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247 |
256 |
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248 |
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if ((*_matching)[right] == INVALID) break;
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249 |
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right = _graph.target((*_matching)[right]);
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250 |
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right = (*_blossom_rep)[_blossom_set->
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251 |
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find(_graph.target((*_ear)[right]))];
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252 |
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if (left_set.find(right) != left_set.end()) {
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253 |
262 |
nca = right;
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254 |
263 |
break;
|
255 |
264 |
}
|
256 |
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right_set.insert(right);
|
257 |
266 |
}
|
258 |
267 |
|
259 |
268 |
if (nca == INVALID) {
|
260 |
269 |
if ((*_matching)[left] == INVALID) {
|
261 |
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nca = right;
|
262 |
271 |
while (left_set.find(nca) == left_set.end()) {
|
263 |
272 |
nca = _graph.target((*_matching)[nca]);
|
264 |
273 |
nca =(*_blossom_rep)[_blossom_set->
|
265 |
274 |
find(_graph.target((*_ear)[nca]))];
|
266 |
275 |
}
|
267 |
276 |
} else {
|
268 |
277 |
nca = left;
|
269 |
278 |
while (right_set.find(nca) == right_set.end()) {
|
270 |
279 |
nca = _graph.target((*_matching)[nca]);
|
271 |
280 |
nca = (*_blossom_rep)[_blossom_set->
|
272 |
281 |
find(_graph.target((*_ear)[nca]))];
|
273 |
282 |
}
|
274 |
283 |
}
|
275 |
284 |
}
|
276 |
285 |
}
|
277 |
286 |
|
278 |
287 |
{
|
279 |
288 |
|
280 |
289 |
Node node = _graph.u(e);
|
281 |
290 |
Arc arc = _graph.direct(e, true);
|
282 |
291 |
Node base = (*_blossom_rep)[_blossom_set->find(node)];
|
283 |
292 |
|
284 |
293 |
while (base != nca) {
|
285 |
294 |
(*_ear)[node] = arc;
|
286 |
295 |
|
287 |
296 |
Node n = node;
|
288 |
297 |
while (n != base) {
|
289 |
298 |
n = _graph.target((*_matching)[n]);
|
290 |
299 |
Arc a = (*_ear)[n];
|
291 |
300 |
n = _graph.target(a);
|
292 |
301 |
(*_ear)[n] = _graph.oppositeArc(a);
|
293 |
302 |
}
|
294 |
303 |
node = _graph.target((*_matching)[base]);
|
295 |
304 |
_tree_set->erase(base);
|
296 |
305 |
_tree_set->erase(node);
|
297 |
306 |
_blossom_set->insert(node, _blossom_set->find(base));
|
298 |
307 |
(*_status)[node] = EVEN;
|
299 |
308 |
_node_queue[_last++] = node;
|
300 |
309 |
arc = _graph.oppositeArc((*_ear)[node]);
|
301 |
310 |
node = _graph.target((*_ear)[node]);
|
302 |
311 |
base = (*_blossom_rep)[_blossom_set->find(node)];
|
303 |
312 |
_blossom_set->join(_graph.target(arc), base);
|
304 |
313 |
}
|
305 |
314 |
}
|
306 |
315 |
|
307 |
316 |
(*_blossom_rep)[_blossom_set->find(nca)] = nca;
|
308 |
317 |
|
309 |
318 |
{
|
310 |
319 |
|
311 |
320 |
Node node = _graph.v(e);
|
312 |
321 |
Arc arc = _graph.direct(e, false);
|
313 |
322 |
Node base = (*_blossom_rep)[_blossom_set->find(node)];
|
314 |
323 |
|
315 |
324 |
while (base != nca) {
|
316 |
325 |
(*_ear)[node] = arc;
|
317 |
326 |
|
318 |
327 |
Node n = node;
|
319 |
328 |
while (n != base) {
|
320 |
329 |
n = _graph.target((*_matching)[n]);
|
321 |
330 |
Arc a = (*_ear)[n];
|
322 |
331 |
n = _graph.target(a);
|
323 |
332 |
(*_ear)[n] = _graph.oppositeArc(a);
|
324 |
333 |
}
|
325 |
334 |
node = _graph.target((*_matching)[base]);
|
326 |
335 |
_tree_set->erase(base);
|
327 |
336 |
_tree_set->erase(node);
|
328 |
337 |
_blossom_set->insert(node, _blossom_set->find(base));
|
329 |
338 |
(*_status)[node] = EVEN;
|
330 |
339 |
_node_queue[_last++] = node;
|
331 |
340 |
arc = _graph.oppositeArc((*_ear)[node]);
|
332 |
341 |
node = _graph.target((*_ear)[node]);
|
333 |
342 |
base = (*_blossom_rep)[_blossom_set->find(node)];
|
334 |
343 |
_blossom_set->join(_graph.target(arc), base);
|
335 |
344 |
}
|
336 |
345 |
}
|
337 |
346 |
|
338 |
347 |
(*_blossom_rep)[_blossom_set->find(nca)] = nca;
|
339 |
348 |
}
|
340 |
349 |
|
341 |
|
|
342 |
|
|
343 |
350 |
void extendOnArc(const Arc& a) {
|
344 |
351 |
Node base = _graph.source(a);
|
345 |
352 |
Node odd = _graph.target(a);
|
346 |
353 |
|
347 |
354 |
(*_ear)[odd] = _graph.oppositeArc(a);
|
348 |
355 |
Node even = _graph.target((*_matching)[odd]);
|
349 |
356 |
(*_blossom_rep)[_blossom_set->insert(even)] = even;
|
350 |
357 |
(*_status)[odd] = ODD;
|
351 |
358 |
(*_status)[even] = EVEN;
|
352 |
359 |
int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(base)]);
|
353 |
360 |
_tree_set->insert(odd, tree);
|
354 |
361 |
_tree_set->insert(even, tree);
|
355 |
362 |
_node_queue[_last++] = even;
|
356 |
363 |
|
357 |
364 |
}
|
358 |
365 |
|
359 |
366 |
void augmentOnArc(const Arc& a) {
|
360 |
367 |
Node even = _graph.source(a);
|
361 |
368 |
Node odd = _graph.target(a);
|
362 |
369 |
|
363 |
370 |
int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(even)]);
|
364 |
371 |
|
365 |
372 |
(*_matching)[odd] = _graph.oppositeArc(a);
|
366 |
373 |
(*_status)[odd] = MATCHED;
|
367 |
374 |
|
368 |
375 |
Arc arc = (*_matching)[even];
|
369 |
376 |
(*_matching)[even] = a;
|
370 |
377 |
|
371 |
378 |
while (arc != INVALID) {
|
372 |
379 |
odd = _graph.target(arc);
|
373 |
380 |
arc = (*_ear)[odd];
|
374 |
381 |
even = _graph.target(arc);
|
375 |
382 |
(*_matching)[odd] = arc;
|
376 |
383 |
arc = (*_matching)[even];
|
377 |
384 |
(*_matching)[even] = _graph.oppositeArc((*_matching)[odd]);
|
378 |
385 |
}
|
379 |
386 |
|
380 |
387 |
for (typename TreeSet::ItemIt it(*_tree_set, tree);
|
381 |
388 |
it != INVALID; ++it) {
|
382 |
389 |
if ((*_status)[it] == ODD) {
|
383 |
390 |
(*_status)[it] = MATCHED;
|
384 |
391 |
} else {
|
385 |
392 |
int blossom = _blossom_set->find(it);
|
386 |
393 |
for (typename BlossomSet::ItemIt jt(*_blossom_set, blossom);
|
387 |
394 |
jt != INVALID; ++jt) {
|
388 |
395 |
(*_status)[jt] = MATCHED;
|
389 |
396 |
}
|
390 |
397 |
_blossom_set->eraseClass(blossom);
|
391 |
398 |
}
|
392 |
399 |
}
|
393 |
400 |
_tree_set->eraseClass(tree);
|
394 |
401 |
|
395 |
402 |
}
|
396 |
403 |
|
397 |
404 |
public:
|
398 |
405 |
|
399 |
406 |
/// \brief Constructor
|
400 |
407 |
///
|
401 |
408 |
/// Constructor.
|
402 |
409 |
MaxMatching(const Graph& graph)
|
403 |
410 |
: _graph(graph), _matching(0), _status(0), _ear(0),
|
404 |
411 |
_blossom_set_index(0), _blossom_set(0), _blossom_rep(0),
|
405 |
412 |
_tree_set_index(0), _tree_set(0) {}
|
406 |
413 |
|
407 |
414 |
~MaxMatching() {
|
408 |
415 |
destroyStructures();
|
409 |
416 |
}
|
410 |
417 |
|
411 |
|
/// \name Execution control
|
|
418 |
/// \name Execution Control
|
412 |
419 |
/// The simplest way to execute the algorithm is to use the
|
413 |
|
/// \c run() member function.
|
414 |
|
/// \n
|
415 |
|
|
416 |
|
/// If you need better control on the execution, you must call
|
417 |
|
/// \ref init(), \ref greedyInit() or \ref matchingInit()
|
418 |
|
/// functions first, then you can start the algorithm with the \ref
|
419 |
|
/// startSparse() or startDense() functions.
|
|
420 |
/// \c run() member function.\n
|
|
421 |
/// If you need better control on the execution, you have to call
|
|
422 |
/// one of the functions \ref init(), \ref greedyInit() or
|
|
423 |
/// \ref matchingInit() first, then you can start the algorithm with
|
|
424 |
/// \ref startSparse() or \ref startDense().
|
420 |
425 |
|
421 |
426 |
///@{
|
422 |
427 |
|
423 |
|
/// \brief Sets the actual matching to the empty matching.
|
|
428 |
/// \brief Set the initial matching to the empty matching.
|
424 |
429 |
///
|
425 |
|
/// Sets the actual matching to the empty matching.
|
426 |
|
///
|
|
430 |
/// This function sets the initial matching to the empty matching.
|
427 |
431 |
void init() {
|
428 |
432 |
createStructures();
|
429 |
433 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
430 |
434 |
(*_matching)[n] = INVALID;
|
431 |
435 |
(*_status)[n] = UNMATCHED;
|
432 |
436 |
}
|
433 |
437 |
}
|
434 |
438 |
|
435 |
|
///\brief Finds an initial matching in a greedy way
|
|
439 |
/// \brief Find an initial matching in a greedy way.
|
436 |
440 |
///
|
437 |
|
///It finds an initial matching in a greedy way.
|
|
441 |
/// This function finds an initial matching in a greedy way.
|
438 |
442 |
void greedyInit() {
|
439 |
443 |
createStructures();
|
440 |
444 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
441 |
445 |
(*_matching)[n] = INVALID;
|
442 |
446 |
(*_status)[n] = UNMATCHED;
|
443 |
447 |
}
|
444 |
448 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
445 |
449 |
if ((*_matching)[n] == INVALID) {
|
446 |
450 |
for (OutArcIt a(_graph, n); a != INVALID ; ++a) {
|
447 |
451 |
Node v = _graph.target(a);
|
448 |
452 |
if ((*_matching)[v] == INVALID && v != n) {
|
449 |
453 |
(*_matching)[n] = a;
|
450 |
454 |
(*_status)[n] = MATCHED;
|
451 |
455 |
(*_matching)[v] = _graph.oppositeArc(a);
|
452 |
456 |
(*_status)[v] = MATCHED;
|
453 |
457 |
break;
|
454 |
458 |
}
|
455 |
459 |
}
|
456 |
460 |
}
|
457 |
461 |
}
|
458 |
462 |
}
|
459 |
463 |
|
460 |
464 |
|
461 |
|
/// \brief Initialize the matching from a map containing.
|
|
465 |
/// \brief Initialize the matching from a map.
|
462 |
466 |
///
|
463 |
|
/// Initialize the matching from a \c bool valued \c Edge map. This
|
464 |
|
/// map must have the property that there are no two incident edges
|
465 |
|
/// with true value, ie. it contains a matching.
|
|
467 |
/// This function initializes the matching from a \c bool valued edge
|
|
468 |
/// map. This map should have the property that there are no two incident
|
|
469 |
/// edges with \c true value, i.e. it really contains a matching.
|
466 |
470 |
/// \return \c true if the map contains a matching.
|
467 |
471 |
template <typename MatchingMap>
|
468 |
472 |
bool matchingInit(const MatchingMap& matching) {
|
469 |
473 |
createStructures();
|
470 |
474 |
|
471 |
475 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
472 |
476 |
(*_matching)[n] = INVALID;
|
473 |
477 |
(*_status)[n] = UNMATCHED;
|
474 |
478 |
}
|
475 |
479 |
for(EdgeIt e(_graph); e!=INVALID; ++e) {
|
476 |
480 |
if (matching[e]) {
|
477 |
481 |
|
478 |
482 |
Node u = _graph.u(e);
|
479 |
483 |
if ((*_matching)[u] != INVALID) return false;
|
480 |
484 |
(*_matching)[u] = _graph.direct(e, true);
|
481 |
485 |
(*_status)[u] = MATCHED;
|
482 |
486 |
|
483 |
487 |
Node v = _graph.v(e);
|
484 |
488 |
if ((*_matching)[v] != INVALID) return false;
|
485 |
489 |
(*_matching)[v] = _graph.direct(e, false);
|
486 |
490 |
(*_status)[v] = MATCHED;
|
487 |
491 |
}
|
488 |
492 |
}
|
489 |
493 |
return true;
|
490 |
494 |
}
|
491 |
495 |
|
492 |
|
/// \brief Starts Edmonds' algorithm
|
|
496 |
/// \brief Start Edmonds' algorithm
|
493 |
497 |
///
|
494 |
|
/// If runs the original Edmonds' algorithm.
|
|
498 |
/// This function runs the original Edmonds' algorithm.
|
|
499 |
///
|
|
500 |
/// \pre \ref Init(), \ref greedyInit() or \ref matchingInit() must be
|
|
501 |
/// called before using this function.
|
495 |
502 |
void startSparse() {
|
496 |
503 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
497 |
504 |
if ((*_status)[n] == UNMATCHED) {
|
498 |
505 |
(*_blossom_rep)[_blossom_set->insert(n)] = n;
|
499 |
506 |
_tree_set->insert(n);
|
500 |
507 |
(*_status)[n] = EVEN;
|
501 |
508 |
processSparse(n);
|
502 |
509 |
}
|
503 |
510 |
}
|
504 |
511 |
}
|
505 |
512 |
|
506 |
|
/// \brief Starts Edmonds' algorithm.
|
|
513 |
/// \brief Start Edmonds' algorithm with a heuristic improvement
|
|
514 |
/// for dense graphs
|
507 |
515 |
///
|
508 |
|
/// It runs Edmonds' algorithm with a heuristic of postponing
|
|
516 |
/// This function runs Edmonds' algorithm with a heuristic of postponing
|
509 |
517 |
/// shrinks, therefore resulting in a faster algorithm for dense graphs.
|
|
518 |
///
|
|
519 |
/// \pre \ref Init(), \ref greedyInit() or \ref matchingInit() must be
|
|
520 |
/// called before using this function.
|
510 |
521 |
void startDense() {
|
511 |
522 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
512 |
523 |
if ((*_status)[n] == UNMATCHED) {
|
513 |
524 |
(*_blossom_rep)[_blossom_set->insert(n)] = n;
|
514 |
525 |
_tree_set->insert(n);
|
515 |
526 |
(*_status)[n] = EVEN;
|
516 |
527 |
processDense(n);
|
517 |
528 |
}
|
518 |
529 |
}
|
519 |
530 |
}
|
520 |
531 |
|
521 |
532 |
|
522 |
|
/// \brief Runs Edmonds' algorithm
|
|
533 |
/// \brief Run Edmonds' algorithm
|
523 |
534 |
///
|
524 |
|
/// Runs Edmonds' algorithm for sparse graphs (<tt>m<2*n</tt>)
|
525 |
|
/// or Edmonds' algorithm with a heuristic of
|
526 |
|
/// postponing shrinks for dense graphs.
|
|
535 |
/// This function runs Edmonds' algorithm. An additional heuristic of
|
|
536 |
/// postponing shrinks is used for relatively dense graphs
|
|
537 |
/// (for which <tt>m>=2*n</tt> holds).
|
527 |
538 |
void run() {
|
528 |
539 |
if (countEdges(_graph) < 2 * countNodes(_graph)) {
|
529 |
540 |
greedyInit();
|
530 |
541 |
startSparse();
|
531 |
542 |
} else {
|
532 |
543 |
init();
|
533 |
544 |
startDense();
|
534 |
545 |
}
|
535 |
546 |
}
|
536 |
547 |
|
537 |
548 |
/// @}
|
538 |
549 |
|
539 |
|
/// \name Primal solution
|
540 |
|
/// Functions to get the primal solution, ie. the matching.
|
|
550 |
/// \name Primal Solution
|
|
551 |
/// Functions to get the primal solution, i.e. the maximum matching.
|
541 |
552 |
|
542 |
553 |
/// @{
|
543 |
554 |
|
544 |
|
///\brief Returns the size of the current matching.
|
|
555 |
/// \brief Return the size (cardinality) of the matching.
|
545 |
556 |
///
|
546 |
|
///Returns the size of the current matching. After \ref
|
547 |
|
///run() it returns the size of the maximum matching in the graph.
|
|
557 |
/// This function returns the size (cardinality) of the current matching.
|
|
558 |
/// After run() it returns the size of the maximum matching in the graph.
|
548 |
559 |
int matchingSize() const {
|
549 |
560 |
int size = 0;
|
550 |
561 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
551 |
562 |
if ((*_matching)[n] != INVALID) {
|
552 |
563 |
++size;
|
553 |
564 |
}
|
554 |
565 |
}
|
555 |
566 |
return size / 2;
|
556 |
567 |
}
|
557 |
568 |
|
558 |
|
/// \brief Returns true when the edge is in the matching.
|
|
569 |
/// \brief Return \c true if the given edge is in the matching.
|
559 |
570 |
///
|
560 |
|
/// Returns true when the edge is in the matching.
|
|
571 |
/// This function returns \c true if the given edge is in the current
|
|
572 |
/// matching.
|
561 |
573 |
bool matching(const Edge& edge) const {
|
562 |
574 |
return edge == (*_matching)[_graph.u(edge)];
|
563 |
575 |
}
|
564 |
576 |
|
565 |
|
/// \brief Returns the matching edge incident to the given node.
|
|
577 |
/// \brief Return the matching arc (or edge) incident to the given node.
|
566 |
578 |
///
|
567 |
|
/// Returns the matching edge of a \c node in the actual matching or
|
568 |
|
/// INVALID if the \c node is not covered by the actual matching.
|
|
579 |
/// This function returns the matching arc (or edge) incident to the
|
|
580 |
/// given node in the current matching or \c INVALID if the node is
|
|
581 |
/// not covered by the matching.
|
569 |
582 |
Arc matching(const Node& n) const {
|
570 |
583 |
return (*_matching)[n];
|
571 |
584 |
}
|
572 |
585 |
|
573 |
|
///\brief Returns the mate of a node in the actual matching.
|
|
586 |
/// \brief Return the mate of the given node.
|
574 |
587 |
///
|
575 |
|
///Returns the mate of a \c node in the actual matching or
|
576 |
|
///INVALID if the \c node is not covered by the actual matching.
|
|
588 |
/// This function returns the mate of the given node in the current
|
|
589 |
/// matching or \c INVALID if the node is not covered by the matching.
|
577 |
590 |
Node mate(const Node& n) const {
|
578 |
591 |
return (*_matching)[n] != INVALID ?
|
579 |
592 |
_graph.target((*_matching)[n]) : INVALID;
|
580 |
593 |
}
|
581 |
594 |
|
582 |
595 |
/// @}
|
583 |
596 |
|
584 |
|
/// \name Dual solution
|
585 |
|
/// Functions to get the dual solution, ie. the decomposition.
|
|
597 |
/// \name Dual Solution
|
|
598 |
/// Functions to get the dual solution, i.e. the Gallai-Edmonds
|
|
599 |
/// decomposition.
|
586 |
600 |
|
587 |
601 |
/// @{
|
588 |
602 |
|
589 |
|
/// \brief Returns the class of the node in the Edmonds-Gallai
|
|
603 |
/// \brief Return the status of the given node in the Edmonds-Gallai
|
590 |
604 |
/// decomposition.
|
591 |
605 |
///
|
592 |
|
/// Returns the class of the node in the Edmonds-Gallai
|
593 |
|
/// decomposition.
|
|
606 |
/// This function returns the \ref Status "status" of the given node
|
|
607 |
/// in the Edmonds-Gallai decomposition.
|
594 |
608 |
Status decomposition(const Node& n) const {
|
595 |
609 |
return (*_status)[n];
|
596 |
610 |
}
|
597 |
611 |
|
598 |
|
/// \brief Returns true when the node is in the barrier.
|
|
612 |
/// \brief Return \c true if the given node is in the barrier.
|
599 |
613 |
///
|
600 |
|
/// Returns true when the node is in the barrier.
|
|
614 |
/// This function returns \c true if the given node is in the barrier.
|
601 |
615 |
bool barrier(const Node& n) const {
|
602 |
616 |
return (*_status)[n] == ODD;
|
603 |
617 |
}
|
604 |
618 |
|
605 |
619 |
/// @}
|
606 |
620 |
|
607 |
621 |
};
|
608 |
622 |
|
609 |
623 |
/// \ingroup matching
|
610 |
624 |
///
|
611 |
625 |
/// \brief Weighted matching in general graphs
|
612 |
626 |
///
|
613 |
627 |
/// This class provides an efficient implementation of Edmond's
|
614 |
628 |
/// maximum weighted matching algorithm. The implementation is based
|
615 |
629 |
/// on extensive use of priority queues and provides
|
616 |
630 |
/// \f$O(nm\log n)\f$ time complexity.
|
617 |
631 |
///
|
618 |
|
/// The maximum weighted matching problem is to find undirected
|
619 |
|
/// edges in the graph with maximum overall weight and no two of
|
620 |
|
/// them shares their ends. The problem can be formulated with the
|
621 |
|
/// following linear program.
|
|
632 |
/// The maximum weighted matching problem is to find a subset of the
|
|
633 |
/// edges in an undirected graph with maximum overall weight for which
|
|
634 |
/// each node has at most one incident edge.
|
|
635 |
/// It can be formulated with the following linear program.
|
622 |
636 |
/// \f[ \sum_{e \in \delta(u)}x_e \le 1 \quad \forall u\in V\f]
|
623 |
637 |
/** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2}
|
624 |
638 |
\quad \forall B\in\mathcal{O}\f] */
|
625 |
639 |
/// \f[x_e \ge 0\quad \forall e\in E\f]
|
626 |
640 |
/// \f[\max \sum_{e\in E}x_ew_e\f]
|
627 |
641 |
/// where \f$\delta(X)\f$ is the set of edges incident to a node in
|
628 |
642 |
/// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in
|
629 |
643 |
/// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality
|
630 |
644 |
/// subsets of the nodes.
|
631 |
645 |
///
|
632 |
646 |
/// The algorithm calculates an optimal matching and a proof of the
|
633 |
647 |
/// optimality. The solution of the dual problem can be used to check
|
634 |
648 |
/// the result of the algorithm. The dual linear problem is the
|
|
649 |
/// following.
|
635 |
650 |
/** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}
|
636 |
651 |
z_B \ge w_{uv} \quad \forall uv\in E\f] */
|
637 |
652 |
/// \f[y_u \ge 0 \quad \forall u \in V\f]
|
638 |
653 |
/// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f]
|
639 |
654 |
/** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}}
|
640 |
655 |
\frac{\vert B \vert - 1}{2}z_B\f] */
|
641 |
656 |
///
|
642 |
|
/// The algorithm can be executed with \c run() or the \c init() and
|
643 |
|
/// then the \c start() member functions. After it the matching can
|
644 |
|
/// be asked with \c matching() or mate() functions. The dual
|
645 |
|
/// solution can be get with \c nodeValue(), \c blossomNum() and \c
|
646 |
|
/// blossomValue() members and \ref MaxWeightedMatching::BlossomIt
|
647 |
|
/// "BlossomIt" nested class, which is able to iterate on the nodes
|
648 |
|
/// of a blossom. If the value type is integral then the dual
|
649 |
|
/// solution is multiplied by \ref MaxWeightedMatching::dualScale "4".
|
|
657 |
/// The algorithm can be executed with the run() function.
|
|
658 |
/// After it the matching (the primal solution) and the dual solution
|
|
659 |
/// can be obtained using the query functions and the
|
|
660 |
/// \ref MaxWeightedMatching::BlossomIt "BlossomIt" nested class,
|
|
661 |
/// which is able to iterate on the nodes of a blossom.
|
|
662 |
/// If the value type is integer, then the dual solution is multiplied
|
|
663 |
/// by \ref MaxWeightedMatching::dualScale "4".
|
|
664 |
///
|
|
665 |
/// \tparam GR The graph type the algorithm runs on.
|
|
666 |
/// \tparam WM The type edge weight map. The default type is
|
|
667 |
/// \ref concepts::Graph::EdgeMap "GR::EdgeMap<int>".
|
|
668 |
#ifdef DOXYGEN
|
|
669 |
template <typename GR, typename WM>
|
|
670 |
#else
|
650 |
671 |
template <typename GR,
|
651 |
672 |
typename WM = typename GR::template EdgeMap<int> >
|
|
673 |
#endif
|
652 |
674 |
class MaxWeightedMatching {
|
653 |
675 |
public:
|
654 |
676 |
|
655 |
|
///\e
|
|
677 |
/// The graph type of the algorithm
|
656 |
678 |
typedef GR Graph;
|
657 |
|
///\e
|
|
679 |
/// The type of the edge weight map
|
658 |
680 |
typedef WM WeightMap;
|
659 |
|
///\e
|
|
681 |
/// The value type of the edge weights
|
660 |
682 |
typedef typename WeightMap::Value Value;
|
661 |
683 |
|
|
684 |
typedef typename Graph::template NodeMap<typename Graph::Arc>
|
|
685 |
MatchingMap;
|
|
686 |
|
662 |
687 |
/// \brief Scaling factor for dual solution
|
663 |
688 |
///
|
664 |
|
/// Scaling factor for dual solution, it is equal to 4 or 1
|
|
689 |
/// Scaling factor for dual solution. It is equal to 4 or 1
|
665 |
690 |
/// according to the value type.
|
666 |
691 |
static const int dualScale =
|
667 |
692 |
std::numeric_limits<Value>::is_integer ? 4 : 1;
|
668 |
693 |
|
669 |
|
typedef typename Graph::template NodeMap<typename Graph::Arc>
|
670 |
|
MatchingMap;
|
671 |
|
|
672 |
694 |
private:
|
673 |
695 |
|
674 |
696 |
TEMPLATE_GRAPH_TYPEDEFS(Graph);
|
675 |
697 |
|
676 |
698 |
typedef typename Graph::template NodeMap<Value> NodePotential;
|
677 |
699 |
typedef std::vector<Node> BlossomNodeList;
|
678 |
700 |
|
679 |
701 |
struct BlossomVariable {
|
680 |
702 |
int begin, end;
|
681 |
703 |
Value value;
|
682 |
704 |
|
683 |
705 |
BlossomVariable(int _begin, int _end, Value _value)
|
684 |
706 |
: begin(_begin), end(_end), value(_value) {}
|
685 |
707 |
|
686 |
708 |
};
|
687 |
709 |
|
688 |
710 |
typedef std::vector<BlossomVariable> BlossomPotential;
|
689 |
711 |
|
690 |
712 |
const Graph& _graph;
|
691 |
713 |
const WeightMap& _weight;
|
692 |
714 |
|
693 |
715 |
MatchingMap* _matching;
|
694 |
716 |
|
695 |
717 |
NodePotential* _node_potential;
|
696 |
718 |
|
697 |
719 |
BlossomPotential _blossom_potential;
|
698 |
720 |
BlossomNodeList _blossom_node_list;
|
699 |
721 |
|
700 |
722 |
int _node_num;
|
701 |
723 |
int _blossom_num;
|
702 |
724 |
|
703 |
725 |
typedef RangeMap<int> IntIntMap;
|
704 |
726 |
|
705 |
727 |
enum Status {
|
706 |
728 |
EVEN = -1, MATCHED = 0, ODD = 1, UNMATCHED = -2
|
707 |
729 |
};
|
708 |
730 |
|
709 |
731 |
typedef HeapUnionFind<Value, IntNodeMap> BlossomSet;
|
710 |
732 |
struct BlossomData {
|
711 |
733 |
int tree;
|
712 |
734 |
Status status;
|
713 |
735 |
Arc pred, next;
|
714 |
736 |
Value pot, offset;
|
715 |
737 |
Node base;
|
716 |
738 |
};
|
717 |
739 |
|
718 |
740 |
IntNodeMap *_blossom_index;
|
719 |
741 |
BlossomSet *_blossom_set;
|
720 |
742 |
RangeMap<BlossomData>* _blossom_data;
|
721 |
743 |
|
722 |
744 |
IntNodeMap *_node_index;
|
723 |
745 |
IntArcMap *_node_heap_index;
|
724 |
746 |
|
725 |
747 |
struct NodeData {
|
726 |
748 |
|
727 |
749 |
NodeData(IntArcMap& node_heap_index)
|
728 |
750 |
: heap(node_heap_index) {}
|
729 |
751 |
|
730 |
752 |
int blossom;
|
731 |
753 |
Value pot;
|
732 |
754 |
BinHeap<Value, IntArcMap> heap;
|
733 |
755 |
std::map<int, Arc> heap_index;
|
734 |
756 |
|
735 |
757 |
int tree;
|
736 |
758 |
};
|
737 |
759 |
|
738 |
760 |
RangeMap<NodeData>* _node_data;
|
739 |
761 |
|
740 |
762 |
typedef ExtendFindEnum<IntIntMap> TreeSet;
|
741 |
763 |
|
742 |
764 |
IntIntMap *_tree_set_index;
|
743 |
765 |
TreeSet *_tree_set;
|
744 |
766 |
|
745 |
767 |
IntNodeMap *_delta1_index;
|
746 |
768 |
BinHeap<Value, IntNodeMap> *_delta1;
|
747 |
769 |
|
748 |
770 |
IntIntMap *_delta2_index;
|
749 |
771 |
BinHeap<Value, IntIntMap> *_delta2;
|
750 |
772 |
|
751 |
773 |
IntEdgeMap *_delta3_index;
|
752 |
774 |
BinHeap<Value, IntEdgeMap> *_delta3;
|
753 |
775 |
|
754 |
776 |
IntIntMap *_delta4_index;
|
755 |
777 |
BinHeap<Value, IntIntMap> *_delta4;
|
756 |
778 |
|
757 |
779 |
Value _delta_sum;
|
758 |
780 |
|
759 |
781 |
void createStructures() {
|
760 |
782 |
_node_num = countNodes(_graph);
|
761 |
783 |
_blossom_num = _node_num * 3 / 2;
|
762 |
784 |
|
763 |
785 |
if (!_matching) {
|
764 |
786 |
_matching = new MatchingMap(_graph);
|
765 |
787 |
}
|
766 |
788 |
if (!_node_potential) {
|
767 |
789 |
_node_potential = new NodePotential(_graph);
|
768 |
790 |
}
|
769 |
791 |
if (!_blossom_set) {
|
770 |
792 |
_blossom_index = new IntNodeMap(_graph);
|
771 |
793 |
_blossom_set = new BlossomSet(*_blossom_index);
|
772 |
794 |
_blossom_data = new RangeMap<BlossomData>(_blossom_num);
|
773 |
795 |
}
|
774 |
796 |
|
775 |
797 |
if (!_node_index) {
|
776 |
798 |
_node_index = new IntNodeMap(_graph);
|
777 |
799 |
_node_heap_index = new IntArcMap(_graph);
|
778 |
800 |
_node_data = new RangeMap<NodeData>(_node_num,
|
779 |
801 |
NodeData(*_node_heap_index));
|
780 |
802 |
}
|
781 |
803 |
|
782 |
804 |
if (!_tree_set) {
|
783 |
805 |
_tree_set_index = new IntIntMap(_blossom_num);
|
784 |
806 |
_tree_set = new TreeSet(*_tree_set_index);
|
785 |
807 |
}
|
786 |
808 |
if (!_delta1) {
|
787 |
809 |
_delta1_index = new IntNodeMap(_graph);
|
788 |
810 |
_delta1 = new BinHeap<Value, IntNodeMap>(*_delta1_index);
|
789 |
811 |
}
|
790 |
812 |
if (!_delta2) {
|
791 |
813 |
_delta2_index = new IntIntMap(_blossom_num);
|
792 |
814 |
_delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index);
|
793 |
815 |
}
|
794 |
816 |
if (!_delta3) {
|
795 |
817 |
_delta3_index = new IntEdgeMap(_graph);
|
796 |
818 |
_delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index);
|
797 |
819 |
}
|
798 |
820 |
if (!_delta4) {
|
799 |
821 |
_delta4_index = new IntIntMap(_blossom_num);
|
800 |
822 |
_delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index);
|
801 |
823 |
}
|
802 |
824 |
}
|
803 |
825 |
|
804 |
826 |
void destroyStructures() {
|
805 |
827 |
_node_num = countNodes(_graph);
|
806 |
828 |
_blossom_num = _node_num * 3 / 2;
|
807 |
829 |
|
808 |
830 |
if (_matching) {
|
809 |
831 |
delete _matching;
|
810 |
832 |
}
|
811 |
833 |
if (_node_potential) {
|
812 |
834 |
delete _node_potential;
|
813 |
835 |
}
|
814 |
836 |
if (_blossom_set) {
|
815 |
837 |
delete _blossom_index;
|
816 |
838 |
delete _blossom_set;
|
817 |
839 |
delete _blossom_data;
|
818 |
840 |
}
|
819 |
841 |
|
820 |
842 |
if (_node_index) {
|
821 |
843 |
delete _node_index;
|
822 |
844 |
delete _node_heap_index;
|
823 |
845 |
delete _node_data;
|
824 |
846 |
}
|
825 |
847 |
|
826 |
848 |
if (_tree_set) {
|
827 |
849 |
delete _tree_set_index;
|
828 |
850 |
delete _tree_set;
|
829 |
851 |
}
|
830 |
852 |
if (_delta1) {
|
831 |
853 |
delete _delta1_index;
|
832 |
854 |
delete _delta1;
|
833 |
855 |
}
|
834 |
856 |
if (_delta2) {
|
835 |
857 |
delete _delta2_index;
|
836 |
858 |
delete _delta2;
|
837 |
859 |
}
|
838 |
860 |
if (_delta3) {
|
839 |
861 |
delete _delta3_index;
|
840 |
862 |
delete _delta3;
|
841 |
863 |
}
|
842 |
864 |
if (_delta4) {
|
843 |
865 |
delete _delta4_index;
|
844 |
866 |
delete _delta4;
|
845 |
867 |
}
|
846 |
868 |
}
|
847 |
869 |
|
848 |
870 |
void matchedToEven(int blossom, int tree) {
|
849 |
871 |
if (_delta2->state(blossom) == _delta2->IN_HEAP) {
|
850 |
872 |
_delta2->erase(blossom);
|
851 |
873 |
}
|
852 |
874 |
|
853 |
875 |
if (!_blossom_set->trivial(blossom)) {
|
854 |
876 |
(*_blossom_data)[blossom].pot -=
|
855 |
877 |
2 * (_delta_sum - (*_blossom_data)[blossom].offset);
|
856 |
878 |
}
|
857 |
879 |
|
858 |
880 |
for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
|
859 |
881 |
n != INVALID; ++n) {
|
860 |
882 |
|
861 |
883 |
_blossom_set->increase(n, std::numeric_limits<Value>::max());
|
862 |
884 |
int ni = (*_node_index)[n];
|
863 |
885 |
|
... |
... |
@@ -1442,753 +1464,798 @@
|
1442 |
1464 |
oddToMatched(blossom);
|
1443 |
1465 |
if (_delta2->state(blossom) == _delta2->IN_HEAP) {
|
1444 |
1466 |
_delta2->erase(blossom);
|
1445 |
1467 |
}
|
1446 |
1468 |
|
1447 |
1469 |
std::vector<int> subblossoms;
|
1448 |
1470 |
_blossom_set->split(blossom, std::back_inserter(subblossoms));
|
1449 |
1471 |
|
1450 |
1472 |
Value offset = (*_blossom_data)[blossom].offset;
|
1451 |
1473 |
int b = _blossom_set->find(_graph.source(pred));
|
1452 |
1474 |
int d = _blossom_set->find(_graph.source(next));
|
1453 |
1475 |
|
1454 |
1476 |
int ib = -1, id = -1;
|
1455 |
1477 |
for (int i = 0; i < int(subblossoms.size()); ++i) {
|
1456 |
1478 |
if (subblossoms[i] == b) ib = i;
|
1457 |
1479 |
if (subblossoms[i] == d) id = i;
|
1458 |
1480 |
|
1459 |
1481 |
(*_blossom_data)[subblossoms[i]].offset = offset;
|
1460 |
1482 |
if (!_blossom_set->trivial(subblossoms[i])) {
|
1461 |
1483 |
(*_blossom_data)[subblossoms[i]].pot -= 2 * offset;
|
1462 |
1484 |
}
|
1463 |
1485 |
if (_blossom_set->classPrio(subblossoms[i]) !=
|
1464 |
1486 |
std::numeric_limits<Value>::max()) {
|
1465 |
1487 |
_delta2->push(subblossoms[i],
|
1466 |
1488 |
_blossom_set->classPrio(subblossoms[i]) -
|
1467 |
1489 |
(*_blossom_data)[subblossoms[i]].offset);
|
1468 |
1490 |
}
|
1469 |
1491 |
}
|
1470 |
1492 |
|
1471 |
1493 |
if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) {
|
1472 |
1494 |
for (int i = (id + 1) % subblossoms.size();
|
1473 |
1495 |
i != ib; i = (i + 2) % subblossoms.size()) {
|
1474 |
1496 |
int sb = subblossoms[i];
|
1475 |
1497 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
1476 |
1498 |
(*_blossom_data)[sb].next =
|
1477 |
1499 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
1478 |
1500 |
}
|
1479 |
1501 |
|
1480 |
1502 |
for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) {
|
1481 |
1503 |
int sb = subblossoms[i];
|
1482 |
1504 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
1483 |
1505 |
int ub = subblossoms[(i + 2) % subblossoms.size()];
|
1484 |
1506 |
|
1485 |
1507 |
(*_blossom_data)[sb].status = ODD;
|
1486 |
1508 |
matchedToOdd(sb);
|
1487 |
1509 |
_tree_set->insert(sb, tree);
|
1488 |
1510 |
(*_blossom_data)[sb].pred = pred;
|
1489 |
1511 |
(*_blossom_data)[sb].next =
|
1490 |
1512 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
1491 |
1513 |
|
1492 |
1514 |
pred = (*_blossom_data)[ub].next;
|
1493 |
1515 |
|
1494 |
1516 |
(*_blossom_data)[tb].status = EVEN;
|
1495 |
1517 |
matchedToEven(tb, tree);
|
1496 |
1518 |
_tree_set->insert(tb, tree);
|
1497 |
1519 |
(*_blossom_data)[tb].pred = (*_blossom_data)[tb].next;
|
1498 |
1520 |
}
|
1499 |
1521 |
|
1500 |
1522 |
(*_blossom_data)[subblossoms[id]].status = ODD;
|
1501 |
1523 |
matchedToOdd(subblossoms[id]);
|
1502 |
1524 |
_tree_set->insert(subblossoms[id], tree);
|
1503 |
1525 |
(*_blossom_data)[subblossoms[id]].next = next;
|
1504 |
1526 |
(*_blossom_data)[subblossoms[id]].pred = pred;
|
1505 |
1527 |
|
1506 |
1528 |
} else {
|
1507 |
1529 |
|
1508 |
1530 |
for (int i = (ib + 1) % subblossoms.size();
|
1509 |
1531 |
i != id; i = (i + 2) % subblossoms.size()) {
|
1510 |
1532 |
int sb = subblossoms[i];
|
1511 |
1533 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
1512 |
1534 |
(*_blossom_data)[sb].next =
|
1513 |
1535 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
1514 |
1536 |
}
|
1515 |
1537 |
|
1516 |
1538 |
for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) {
|
1517 |
1539 |
int sb = subblossoms[i];
|
1518 |
1540 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
1519 |
1541 |
int ub = subblossoms[(i + 2) % subblossoms.size()];
|
1520 |
1542 |
|
1521 |
1543 |
(*_blossom_data)[sb].status = ODD;
|
1522 |
1544 |
matchedToOdd(sb);
|
1523 |
1545 |
_tree_set->insert(sb, tree);
|
1524 |
1546 |
(*_blossom_data)[sb].next = next;
|
1525 |
1547 |
(*_blossom_data)[sb].pred =
|
1526 |
1548 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
1527 |
1549 |
|
1528 |
1550 |
(*_blossom_data)[tb].status = EVEN;
|
1529 |
1551 |
matchedToEven(tb, tree);
|
1530 |
1552 |
_tree_set->insert(tb, tree);
|
1531 |
1553 |
(*_blossom_data)[tb].pred =
|
1532 |
1554 |
(*_blossom_data)[tb].next =
|
1533 |
1555 |
_graph.oppositeArc((*_blossom_data)[ub].next);
|
1534 |
1556 |
next = (*_blossom_data)[ub].next;
|
1535 |
1557 |
}
|
1536 |
1558 |
|
1537 |
1559 |
(*_blossom_data)[subblossoms[ib]].status = ODD;
|
1538 |
1560 |
matchedToOdd(subblossoms[ib]);
|
1539 |
1561 |
_tree_set->insert(subblossoms[ib], tree);
|
1540 |
1562 |
(*_blossom_data)[subblossoms[ib]].next = next;
|
1541 |
1563 |
(*_blossom_data)[subblossoms[ib]].pred = pred;
|
1542 |
1564 |
}
|
1543 |
1565 |
_tree_set->erase(blossom);
|
1544 |
1566 |
}
|
1545 |
1567 |
|
1546 |
1568 |
void extractBlossom(int blossom, const Node& base, const Arc& matching) {
|
1547 |
1569 |
if (_blossom_set->trivial(blossom)) {
|
1548 |
1570 |
int bi = (*_node_index)[base];
|
1549 |
1571 |
Value pot = (*_node_data)[bi].pot;
|
1550 |
1572 |
|
1551 |
1573 |
(*_matching)[base] = matching;
|
1552 |
1574 |
_blossom_node_list.push_back(base);
|
1553 |
1575 |
(*_node_potential)[base] = pot;
|
1554 |
1576 |
} else {
|
1555 |
1577 |
|
1556 |
1578 |
Value pot = (*_blossom_data)[blossom].pot;
|
1557 |
1579 |
int bn = _blossom_node_list.size();
|
1558 |
1580 |
|
1559 |
1581 |
std::vector<int> subblossoms;
|
1560 |
1582 |
_blossom_set->split(blossom, std::back_inserter(subblossoms));
|
1561 |
1583 |
int b = _blossom_set->find(base);
|
1562 |
1584 |
int ib = -1;
|
1563 |
1585 |
for (int i = 0; i < int(subblossoms.size()); ++i) {
|
1564 |
1586 |
if (subblossoms[i] == b) { ib = i; break; }
|
1565 |
1587 |
}
|
1566 |
1588 |
|
1567 |
1589 |
for (int i = 1; i < int(subblossoms.size()); i += 2) {
|
1568 |
1590 |
int sb = subblossoms[(ib + i) % subblossoms.size()];
|
1569 |
1591 |
int tb = subblossoms[(ib + i + 1) % subblossoms.size()];
|
1570 |
1592 |
|
1571 |
1593 |
Arc m = (*_blossom_data)[tb].next;
|
1572 |
1594 |
extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m));
|
1573 |
1595 |
extractBlossom(tb, _graph.source(m), m);
|
1574 |
1596 |
}
|
1575 |
1597 |
extractBlossom(subblossoms[ib], base, matching);
|
1576 |
1598 |
|
1577 |
1599 |
int en = _blossom_node_list.size();
|
1578 |
1600 |
|
1579 |
1601 |
_blossom_potential.push_back(BlossomVariable(bn, en, pot));
|
1580 |
1602 |
}
|
1581 |
1603 |
}
|
1582 |
1604 |
|
1583 |
1605 |
void extractMatching() {
|
1584 |
1606 |
std::vector<int> blossoms;
|
1585 |
1607 |
for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) {
|
1586 |
1608 |
blossoms.push_back(c);
|
1587 |
1609 |
}
|
1588 |
1610 |
|
1589 |
1611 |
for (int i = 0; i < int(blossoms.size()); ++i) {
|
1590 |
1612 |
if ((*_blossom_data)[blossoms[i]].status == MATCHED) {
|
1591 |
1613 |
|
1592 |
1614 |
Value offset = (*_blossom_data)[blossoms[i]].offset;
|
1593 |
1615 |
(*_blossom_data)[blossoms[i]].pot += 2 * offset;
|
1594 |
1616 |
for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]);
|
1595 |
1617 |
n != INVALID; ++n) {
|
1596 |
1618 |
(*_node_data)[(*_node_index)[n]].pot -= offset;
|
1597 |
1619 |
}
|
1598 |
1620 |
|
1599 |
1621 |
Arc matching = (*_blossom_data)[blossoms[i]].next;
|
1600 |
1622 |
Node base = _graph.source(matching);
|
1601 |
1623 |
extractBlossom(blossoms[i], base, matching);
|
1602 |
1624 |
} else {
|
1603 |
1625 |
Node base = (*_blossom_data)[blossoms[i]].base;
|
1604 |
1626 |
extractBlossom(blossoms[i], base, INVALID);
|
1605 |
1627 |
}
|
1606 |
1628 |
}
|
1607 |
1629 |
}
|
1608 |
1630 |
|
1609 |
1631 |
public:
|
1610 |
1632 |
|
1611 |
1633 |
/// \brief Constructor
|
1612 |
1634 |
///
|
1613 |
1635 |
/// Constructor.
|
1614 |
1636 |
MaxWeightedMatching(const Graph& graph, const WeightMap& weight)
|
1615 |
1637 |
: _graph(graph), _weight(weight), _matching(0),
|
1616 |
1638 |
_node_potential(0), _blossom_potential(), _blossom_node_list(),
|
1617 |
1639 |
_node_num(0), _blossom_num(0),
|
1618 |
1640 |
|
1619 |
1641 |
_blossom_index(0), _blossom_set(0), _blossom_data(0),
|
1620 |
1642 |
_node_index(0), _node_heap_index(0), _node_data(0),
|
1621 |
1643 |
_tree_set_index(0), _tree_set(0),
|
1622 |
1644 |
|
1623 |
1645 |
_delta1_index(0), _delta1(0),
|
1624 |
1646 |
_delta2_index(0), _delta2(0),
|
1625 |
1647 |
_delta3_index(0), _delta3(0),
|
1626 |
1648 |
_delta4_index(0), _delta4(0),
|
1627 |
1649 |
|
1628 |
1650 |
_delta_sum() {}
|
1629 |
1651 |
|
1630 |
1652 |
~MaxWeightedMatching() {
|
1631 |
1653 |
destroyStructures();
|
1632 |
1654 |
}
|
1633 |
1655 |
|
1634 |
|
/// \name Execution control
|
|
1656 |
/// \name Execution Control
|
1635 |
1657 |
/// The simplest way to execute the algorithm is to use the
|
1636 |
|
/// \c run() member function.
|
|
1658 |
/// \ref run() member function.
|
1637 |
1659 |
|
1638 |
1660 |
///@{
|
1639 |
1661 |
|
1640 |
1662 |
/// \brief Initialize the algorithm
|
1641 |
1663 |
///
|
1642 |
|
/// Initialize the algorithm
|
|
1664 |
/// This function initializes the algorithm.
|
1643 |
1665 |
void init() {
|
1644 |
1666 |
createStructures();
|
1645 |
1667 |
|
1646 |
1668 |
for (ArcIt e(_graph); e != INVALID; ++e) {
|
1647 |
1669 |
(*_node_heap_index)[e] = BinHeap<Value, IntArcMap>::PRE_HEAP;
|
1648 |
1670 |
}
|
1649 |
1671 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
1650 |
1672 |
(*_delta1_index)[n] = _delta1->PRE_HEAP;
|
1651 |
1673 |
}
|
1652 |
1674 |
for (EdgeIt e(_graph); e != INVALID; ++e) {
|
1653 |
1675 |
(*_delta3_index)[e] = _delta3->PRE_HEAP;
|
1654 |
1676 |
}
|
1655 |
1677 |
for (int i = 0; i < _blossom_num; ++i) {
|
1656 |
1678 |
(*_delta2_index)[i] = _delta2->PRE_HEAP;
|
1657 |
1679 |
(*_delta4_index)[i] = _delta4->PRE_HEAP;
|
1658 |
1680 |
}
|
1659 |
1681 |
|
1660 |
1682 |
int index = 0;
|
1661 |
1683 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
1662 |
1684 |
Value max = 0;
|
1663 |
1685 |
for (OutArcIt e(_graph, n); e != INVALID; ++e) {
|
1664 |
1686 |
if (_graph.target(e) == n) continue;
|
1665 |
1687 |
if ((dualScale * _weight[e]) / 2 > max) {
|
1666 |
1688 |
max = (dualScale * _weight[e]) / 2;
|
1667 |
1689 |
}
|
1668 |
1690 |
}
|
1669 |
1691 |
(*_node_index)[n] = index;
|
1670 |
1692 |
(*_node_data)[index].pot = max;
|
1671 |
1693 |
_delta1->push(n, max);
|
1672 |
1694 |
int blossom =
|
1673 |
1695 |
_blossom_set->insert(n, std::numeric_limits<Value>::max());
|
1674 |
1696 |
|
1675 |
1697 |
_tree_set->insert(blossom);
|
1676 |
1698 |
|
1677 |
1699 |
(*_blossom_data)[blossom].status = EVEN;
|
1678 |
1700 |
(*_blossom_data)[blossom].pred = INVALID;
|
1679 |
1701 |
(*_blossom_data)[blossom].next = INVALID;
|
1680 |
1702 |
(*_blossom_data)[blossom].pot = 0;
|
1681 |
1703 |
(*_blossom_data)[blossom].offset = 0;
|
1682 |
1704 |
++index;
|
1683 |
1705 |
}
|
1684 |
1706 |
for (EdgeIt e(_graph); e != INVALID; ++e) {
|
1685 |
1707 |
int si = (*_node_index)[_graph.u(e)];
|
1686 |
1708 |
int ti = (*_node_index)[_graph.v(e)];
|
1687 |
1709 |
if (_graph.u(e) != _graph.v(e)) {
|
1688 |
1710 |
_delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot -
|
1689 |
1711 |
dualScale * _weight[e]) / 2);
|
1690 |
1712 |
}
|
1691 |
1713 |
}
|
1692 |
1714 |
}
|
1693 |
1715 |
|
1694 |
|
/// \brief Starts the algorithm
|
|
1716 |
/// \brief Start the algorithm
|
1695 |
1717 |
///
|
1696 |
|
/// Starts the algorithm
|
|
1718 |
/// This function starts the algorithm.
|
|
1719 |
///
|
|
1720 |
/// \pre \ref init() must be called before using this function.
|
1697 |
1721 |
void start() {
|
1698 |
1722 |
enum OpType {
|
1699 |
1723 |
D1, D2, D3, D4
|
1700 |
1724 |
};
|
1701 |
1725 |
|
1702 |
1726 |
int unmatched = _node_num;
|
1703 |
1727 |
while (unmatched > 0) {
|
1704 |
1728 |
Value d1 = !_delta1->empty() ?
|
1705 |
1729 |
_delta1->prio() : std::numeric_limits<Value>::max();
|
1706 |
1730 |
|
1707 |
1731 |
Value d2 = !_delta2->empty() ?
|
1708 |
1732 |
_delta2->prio() : std::numeric_limits<Value>::max();
|
1709 |
1733 |
|
1710 |
1734 |
Value d3 = !_delta3->empty() ?
|
1711 |
1735 |
_delta3->prio() : std::numeric_limits<Value>::max();
|
1712 |
1736 |
|
1713 |
1737 |
Value d4 = !_delta4->empty() ?
|
1714 |
1738 |
_delta4->prio() : std::numeric_limits<Value>::max();
|
1715 |
1739 |
|
1716 |
1740 |
_delta_sum = d1; OpType ot = D1;
|
1717 |
1741 |
if (d2 < _delta_sum) { _delta_sum = d2; ot = D2; }
|
1718 |
1742 |
if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; }
|
1719 |
1743 |
if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; }
|
1720 |
1744 |
|
1721 |
1745 |
|
1722 |
1746 |
switch (ot) {
|
1723 |
1747 |
case D1:
|
1724 |
1748 |
{
|
1725 |
1749 |
Node n = _delta1->top();
|
1726 |
1750 |
unmatchNode(n);
|
1727 |
1751 |
--unmatched;
|
1728 |
1752 |
}
|
1729 |
1753 |
break;
|
1730 |
1754 |
case D2:
|
1731 |
1755 |
{
|
1732 |
1756 |
int blossom = _delta2->top();
|
1733 |
1757 |
Node n = _blossom_set->classTop(blossom);
|
1734 |
1758 |
Arc e = (*_node_data)[(*_node_index)[n]].heap.top();
|
1735 |
1759 |
extendOnArc(e);
|
1736 |
1760 |
}
|
1737 |
1761 |
break;
|
1738 |
1762 |
case D3:
|
1739 |
1763 |
{
|
1740 |
1764 |
Edge e = _delta3->top();
|
1741 |
1765 |
|
1742 |
1766 |
int left_blossom = _blossom_set->find(_graph.u(e));
|
1743 |
1767 |
int right_blossom = _blossom_set->find(_graph.v(e));
|
1744 |
1768 |
|
1745 |
1769 |
if (left_blossom == right_blossom) {
|
1746 |
1770 |
_delta3->pop();
|
1747 |
1771 |
} else {
|
1748 |
1772 |
int left_tree;
|
1749 |
1773 |
if ((*_blossom_data)[left_blossom].status == EVEN) {
|
1750 |
1774 |
left_tree = _tree_set->find(left_blossom);
|
1751 |
1775 |
} else {
|
1752 |
1776 |
left_tree = -1;
|
1753 |
1777 |
++unmatched;
|
1754 |
1778 |
}
|
1755 |
1779 |
int right_tree;
|
1756 |
1780 |
if ((*_blossom_data)[right_blossom].status == EVEN) {
|
1757 |
1781 |
right_tree = _tree_set->find(right_blossom);
|
1758 |
1782 |
} else {
|
1759 |
1783 |
right_tree = -1;
|
1760 |
1784 |
++unmatched;
|
1761 |
1785 |
}
|
1762 |
1786 |
|
1763 |
1787 |
if (left_tree == right_tree) {
|
1764 |
1788 |
shrinkOnEdge(e, left_tree);
|
1765 |
1789 |
} else {
|
1766 |
1790 |
augmentOnEdge(e);
|
1767 |
1791 |
unmatched -= 2;
|
1768 |
1792 |
}
|
1769 |
1793 |
}
|
1770 |
1794 |
} break;
|
1771 |
1795 |
case D4:
|
1772 |
1796 |
splitBlossom(_delta4->top());
|
1773 |
1797 |
break;
|
1774 |
1798 |
}
|
1775 |
1799 |
}
|
1776 |
1800 |
extractMatching();
|
1777 |
1801 |
}
|
1778 |
1802 |
|
1779 |
|
/// \brief Runs %MaxWeightedMatching algorithm.
|
|
1803 |
/// \brief Run the algorithm.
|
1780 |
1804 |
///
|
1781 |
|
/// This method runs the %MaxWeightedMatching algorithm.
|
|
1805 |
/// This method runs the \c %MaxWeightedMatching algorithm.
|
1782 |
1806 |
///
|
1783 |
1807 |
/// \note mwm.run() is just a shortcut of the following code.
|
1784 |
1808 |
/// \code
|
1785 |
1809 |
/// mwm.init();
|
1786 |
1810 |
/// mwm.start();
|
1787 |
1811 |
/// \endcode
|
1788 |
1812 |
void run() {
|
1789 |
1813 |
init();
|
1790 |
1814 |
start();
|
1791 |
1815 |
}
|
1792 |
1816 |
|
1793 |
1817 |
/// @}
|
1794 |
1818 |
|
1795 |
|
/// \name Primal solution
|
1796 |
|
/// Functions to get the primal solution, ie. the matching.
|
|
1819 |
/// \name Primal Solution
|
|
1820 |
/// Functions to get the primal solution, i.e. the maximum weighted
|
|
1821 |
/// matching.\n
|
|
1822 |
/// Either \ref run() or \ref start() function should be called before
|
|
1823 |
/// using them.
|
1797 |
1824 |
|
1798 |
1825 |
/// @{
|
1799 |
1826 |
|
1800 |
|
/// \brief Returns the weight of the matching.
|
|
1827 |
/// \brief Return the weight of the matching.
|
1801 |
1828 |
///
|
1802 |
|
/// Returns the weight of the matching.
|
|
1829 |
/// This function returns the weight of the found matching.
|
|
1830 |
///
|
|
1831 |
/// \pre Either run() or start() must be called before using this function.
|
1803 |
1832 |
Value matchingValue() const {
|
1804 |
1833 |
Value sum = 0;
|
1805 |
1834 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
1806 |
1835 |
if ((*_matching)[n] != INVALID) {
|
1807 |
1836 |
sum += _weight[(*_matching)[n]];
|
1808 |
1837 |
}
|
1809 |
1838 |
}
|
1810 |
1839 |
return sum /= 2;
|
1811 |
1840 |
}
|
1812 |
1841 |
|
1813 |
|
/// \brief Returns the cardinality of the matching.
|
|
1842 |
/// \brief Return the size (cardinality) of the matching.
|
1814 |
1843 |
///
|
1815 |
|
/// Returns the cardinality of the matching.
|
|
1844 |
/// This function returns the size (cardinality) of the found matching.
|
|
1845 |
///
|
|
1846 |
/// \pre Either run() or start() must be called before using this function.
|
1816 |
1847 |
int matchingSize() const {
|
1817 |
1848 |
int num = 0;
|
1818 |
1849 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
1819 |
1850 |
if ((*_matching)[n] != INVALID) {
|
1820 |
1851 |
++num;
|
1821 |
1852 |
}
|
1822 |
1853 |
}
|
1823 |
1854 |
return num /= 2;
|
1824 |
1855 |
}
|
1825 |
1856 |
|
1826 |
|
/// \brief Returns true when the edge is in the matching.
|
|
1857 |
/// \brief Return \c true if the given edge is in the matching.
|
1827 |
1858 |
///
|
1828 |
|
/// Returns true when the edge is in the matching.
|
|
1859 |
/// This function returns \c true if the given edge is in the found
|
|
1860 |
/// matching.
|
|
1861 |
///
|
|
1862 |
/// \pre Either run() or start() must be called before using this function.
|
1829 |
1863 |
bool matching(const Edge& edge) const {
|
1830 |
1864 |
return edge == (*_matching)[_graph.u(edge)];
|
1831 |
1865 |
}
|
1832 |
1866 |
|
1833 |
|
/// \brief Returns the incident matching arc.
|
|
1867 |
/// \brief Return the matching arc (or edge) incident to the given node.
|
1834 |
1868 |
///
|
1835 |
|
/// Returns the incident matching arc from given node. If the
|
1836 |
|
/// node is not matched then it gives back \c INVALID.
|
|
1869 |
/// This function returns the matching arc (or edge) incident to the
|
|
1870 |
/// given node in the found matching or \c INVALID if the node is
|
|
1871 |
/// not covered by the matching.
|
|
1872 |
///
|
|
1873 |
/// \pre Either run() or start() must be called before using this function.
|
1837 |
1874 |
Arc matching(const Node& node) const {
|
1838 |
1875 |
return (*_matching)[node];
|
1839 |
1876 |
}
|
1840 |
1877 |
|
1841 |
|
/// \brief Returns the mate of the node.
|
|
1878 |
/// \brief Return the mate of the given node.
|
1842 |
1879 |
///
|
1843 |
|
/// Returns the adjancent node in a mathcing arc. If the node is
|
1844 |
|
/// not matched then it gives back \c INVALID.
|
|
1880 |
/// This function returns the mate of the given node in the found
|
|
1881 |
/// matching or \c INVALID if the node is not covered by the matching.
|
|
1882 |
///
|
|
1883 |
/// \pre Either run() or start() must be called before using this function.
|
1845 |
1884 |
Node mate(const Node& node) const {
|
1846 |
1885 |
return (*_matching)[node] != INVALID ?
|
1847 |
1886 |
_graph.target((*_matching)[node]) : INVALID;
|
1848 |
1887 |
}
|
1849 |
1888 |
|
1850 |
1889 |
/// @}
|
1851 |
1890 |
|
1852 |
|
/// \name Dual solution
|
1853 |
|
/// Functions to get the dual solution.
|
|
1891 |
/// \name Dual Solution
|
|
1892 |
/// Functions to get the dual solution.\n
|
|
1893 |
/// Either \ref run() or \ref start() function should be called before
|
|
1894 |
/// using them.
|
1854 |
1895 |
|
1855 |
1896 |
/// @{
|
1856 |
1897 |
|
1857 |
|
/// \brief Returns the value of the dual solution.
|
|
1898 |
/// \brief Return the value of the dual solution.
|
1858 |
1899 |
///
|
1859 |
|
/// Returns the value of the dual solution. It should be equal to
|
1860 |
|
/// the primal value scaled by \ref dualScale "dual scale".
|
|
1900 |
/// This function returns the value of the dual solution.
|
|
1901 |
/// It should be equal to the primal value scaled by \ref dualScale
|
|
1902 |
/// "dual scale".
|
|
1903 |
///
|
|
1904 |
/// \pre Either run() or start() must be called before using this function.
|
1861 |
1905 |
Value dualValue() const {
|
1862 |
1906 |
Value sum = 0;
|
1863 |
1907 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
1864 |
1908 |
sum += nodeValue(n);
|
1865 |
1909 |
}
|
1866 |
1910 |
for (int i = 0; i < blossomNum(); ++i) {
|
1867 |
1911 |
sum += blossomValue(i) * (blossomSize(i) / 2);
|
1868 |
1912 |
}
|
1869 |
1913 |
return sum;
|
1870 |
1914 |
}
|
1871 |
1915 |
|
1872 |
|
/// \brief Returns the value of the node.
|
|
1916 |
/// \brief Return the dual value (potential) of the given node.
|
1873 |
1917 |
///
|
1874 |
|
/// Returns the the value of the node.
|
|
1918 |
/// This function returns the dual value (potential) of the given node.
|
|
1919 |
///
|
|
1920 |
/// \pre Either run() or start() must be called before using this function.
|
1875 |
1921 |
Value nodeValue(const Node& n) const {
|
1876 |
1922 |
return (*_node_potential)[n];
|
1877 |
1923 |
}
|
1878 |
1924 |
|
1879 |
|
/// \brief Returns the number of the blossoms in the basis.
|
|
1925 |
/// \brief Return the number of the blossoms in the basis.
|
1880 |
1926 |
///
|
1881 |
|
/// Returns the number of the blossoms in the basis.
|
|
1927 |
/// This function returns the number of the blossoms in the basis.
|
|
1928 |
///
|
|
1929 |
/// \pre Either run() or start() must be called before using this function.
|
1882 |
1930 |
/// \see BlossomIt
|
1883 |
1931 |
int blossomNum() const {
|
1884 |
1932 |
return _blossom_potential.size();
|
1885 |
1933 |
}
|
1886 |
1934 |
|
1887 |
|
|
1888 |
|
/// \brief Returns the number of the nodes in the blossom.
|
|
1935 |
/// \brief Return the number of the nodes in the given blossom.
|
1889 |
1936 |
///
|
1890 |
|
/// Returns the number of the nodes in the blossom.
|
|
1937 |
/// This function returns the number of the nodes in the given blossom.
|
|
1938 |
///
|
|
1939 |
/// \pre Either run() or start() must be called before using this function.
|
|
1940 |
/// \see BlossomIt
|
1891 |
1941 |
int blossomSize(int k) const {
|
1892 |
1942 |
return _blossom_potential[k].end - _blossom_potential[k].begin;
|
1893 |
1943 |
}
|
1894 |
1944 |
|
1895 |
|
/// \brief Returns the value of the blossom.
|
|
1945 |
/// \brief Return the dual value (ptential) of the given blossom.
|
1896 |
1946 |
///
|
1897 |
|
/// Returns the the value of the blossom.
|
1898 |
|
/// \see BlossomIt
|
|
1947 |
/// This function returns the dual value (ptential) of the given blossom.
|
|
1948 |
///
|
|
1949 |
/// \pre Either run() or start() must be called before using this function.
|
1899 |
1950 |
Value blossomValue(int k) const {
|
1900 |
1951 |
return _blossom_potential[k].value;
|
1901 |
1952 |
}
|
1902 |
1953 |
|
1903 |
|
/// \brief Iterator for obtaining the nodes of the blossom.
|
|
1954 |
/// \brief Iterator for obtaining the nodes of a blossom.
|
1904 |
1955 |
///
|
1905 |
|
/// Iterator for obtaining the nodes of the blossom. This class
|
1906 |
|
/// provides a common lemon style iterator for listing a
|
1907 |
|
/// subset of the nodes.
|
|
1956 |
/// This class provides an iterator for obtaining the nodes of the
|
|
1957 |
/// given blossom. It lists a subset of the nodes.
|
|
1958 |
/// Before using this iterator, you must allocate a
|
|
1959 |
/// MaxWeightedMatching class and execute it.
|
1908 |
1960 |
class BlossomIt {
|
1909 |
1961 |
public:
|
1910 |
1962 |
|
1911 |
1963 |
/// \brief Constructor.
|
1912 |
1964 |
///
|
1913 |
|
/// Constructor to get the nodes of the variable.
|
|
1965 |
/// Constructor to get the nodes of the given variable.
|
|
1966 |
///
|
|
1967 |
/// \pre Either \ref MaxWeightedMatching::run() "algorithm.run()" or
|
|
1968 |
/// \ref MaxWeightedMatching::start() "algorithm.start()" must be
|
|
1969 |
/// called before initializing this iterator.
|
1914 |
1970 |
BlossomIt(const MaxWeightedMatching& algorithm, int variable)
|
1915 |
1971 |
: _algorithm(&algorithm)
|
1916 |
1972 |
{
|
1917 |
1973 |
_index = _algorithm->_blossom_potential[variable].begin;
|
1918 |
1974 |
_last = _algorithm->_blossom_potential[variable].end;
|
1919 |
1975 |
}
|
1920 |
1976 |
|
1921 |
|
/// \brief Conversion to node.
|
|
1977 |
/// \brief Conversion to \c Node.
|
1922 |
1978 |
///
|
1923 |
|
/// Conversion to node.
|
|
1979 |
/// Conversion to \c Node.
|
1924 |
1980 |
operator Node() const {
|
1925 |
1981 |
return _algorithm->_blossom_node_list[_index];
|
1926 |
1982 |
}
|
1927 |
1983 |
|
1928 |
1984 |
/// \brief Increment operator.
|
1929 |
1985 |
///
|
1930 |
1986 |
/// Increment operator.
|
1931 |
1987 |
BlossomIt& operator++() {
|
1932 |
1988 |
++_index;
|
1933 |
1989 |
return *this;
|
1934 |
1990 |
}
|
1935 |
1991 |
|
1936 |
1992 |
/// \brief Validity checking
|
1937 |
1993 |
///
|
1938 |
1994 |
/// Checks whether the iterator is invalid.
|
1939 |
1995 |
bool operator==(Invalid) const { return _index == _last; }
|
1940 |
1996 |
|
1941 |
1997 |
/// \brief Validity checking
|
1942 |
1998 |
///
|
1943 |
1999 |
/// Checks whether the iterator is valid.
|
1944 |
2000 |
bool operator!=(Invalid) const { return _index != _last; }
|
1945 |
2001 |
|
1946 |
2002 |
private:
|
1947 |
2003 |
const MaxWeightedMatching* _algorithm;
|
1948 |
2004 |
int _last;
|
1949 |
2005 |
int _index;
|
1950 |
2006 |
};
|
1951 |
2007 |
|
1952 |
2008 |
/// @}
|
1953 |
2009 |
|
1954 |
2010 |
};
|
1955 |
2011 |
|
1956 |
2012 |
/// \ingroup matching
|
1957 |
2013 |
///
|
1958 |
2014 |
/// \brief Weighted perfect matching in general graphs
|
1959 |
2015 |
///
|
1960 |
2016 |
/// This class provides an efficient implementation of Edmond's
|
1961 |
2017 |
/// maximum weighted perfect matching algorithm. The implementation
|
1962 |
2018 |
/// is based on extensive use of priority queues and provides
|
1963 |
2019 |
/// \f$O(nm\log n)\f$ time complexity.
|
1964 |
2020 |
///
|
1965 |
|
/// The maximum weighted matching problem is to find undirected
|
1966 |
|
/// edges in the graph with maximum overall weight and no two of
|
1967 |
|
/// them shares their ends and covers all nodes. The problem can be
|
1968 |
|
/// formulated with the following linear program.
|
|
2021 |
/// The maximum weighted perfect matching problem is to find a subset of
|
|
2022 |
/// the edges in an undirected graph with maximum overall weight for which
|
|
2023 |
/// each node has exactly one incident edge.
|
|
2024 |
/// It can be formulated with the following linear program.
|
1969 |
2025 |
/// \f[ \sum_{e \in \delta(u)}x_e = 1 \quad \forall u\in V\f]
|
1970 |
2026 |
/** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2}
|
1971 |
2027 |
\quad \forall B\in\mathcal{O}\f] */
|
1972 |
2028 |
/// \f[x_e \ge 0\quad \forall e\in E\f]
|
1973 |
2029 |
/// \f[\max \sum_{e\in E}x_ew_e\f]
|
1974 |
2030 |
/// where \f$\delta(X)\f$ is the set of edges incident to a node in
|
1975 |
2031 |
/// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in
|
1976 |
2032 |
/// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality
|
1977 |
2033 |
/// subsets of the nodes.
|
1978 |
2034 |
///
|
1979 |
2035 |
/// The algorithm calculates an optimal matching and a proof of the
|
1980 |
2036 |
/// optimality. The solution of the dual problem can be used to check
|
1981 |
2037 |
/// the result of the algorithm. The dual linear problem is the
|
|
2038 |
/// following.
|
1982 |
2039 |
/** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}z_B \ge
|
1983 |
2040 |
w_{uv} \quad \forall uv\in E\f] */
|
1984 |
2041 |
/// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f]
|
1985 |
2042 |
/** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}}
|
1986 |
2043 |
\frac{\vert B \vert - 1}{2}z_B\f] */
|
1987 |
2044 |
///
|
1988 |
|
/// The algorithm can be executed with \c run() or the \c init() and
|
1989 |
|
/// then the \c start() member functions. After it the matching can
|
1990 |
|
/// be asked with \c matching() or mate() functions. The dual
|
1991 |
|
/// solution can be get with \c nodeValue(), \c blossomNum() and \c
|
1992 |
|
/// blossomValue() members and \ref MaxWeightedMatching::BlossomIt
|
1993 |
|
/// "BlossomIt" nested class which is able to iterate on the nodes
|
1994 |
|
/// of a blossom. If the value type is integral then the dual
|
1995 |
|
/// solution is multiplied by \ref MaxWeightedMatching::dualScale "4".
|
|
2045 |
/// The algorithm can be executed with the run() function.
|
|
2046 |
/// After it the matching (the primal solution) and the dual solution
|
|
2047 |
/// can be obtained using the query functions and the
|
|
2048 |
/// \ref MaxWeightedPerfectMatching::BlossomIt "BlossomIt" nested class,
|
|
2049 |
/// which is able to iterate on the nodes of a blossom.
|
|
2050 |
/// If the value type is integer, then the dual solution is multiplied
|
|
2051 |
/// by \ref MaxWeightedMatching::dualScale "4".
|
|
2052 |
///
|
|
2053 |
/// \tparam GR The graph type the algorithm runs on.
|
|
2054 |
/// \tparam WM The type edge weight map. The default type is
|
|
2055 |
/// \ref concepts::Graph::EdgeMap "GR::EdgeMap<int>".
|
|
2056 |
#ifdef DOXYGEN
|
|
2057 |
template <typename GR, typename WM>
|
|
2058 |
#else
|
1996 |
2059 |
template <typename GR,
|
1997 |
2060 |
typename WM = typename GR::template EdgeMap<int> >
|
|
2061 |
#endif
|
1998 |
2062 |
class MaxWeightedPerfectMatching {
|
1999 |
2063 |
public:
|
2000 |
2064 |
|
|
2065 |
/// The graph type of the algorithm
|
2001 |
2066 |
typedef GR Graph;
|
|
2067 |
/// The type of the edge weight map
|
2002 |
2068 |
typedef WM WeightMap;
|
|
2069 |
/// The value type of the edge weights
|
2003 |
2070 |
typedef typename WeightMap::Value Value;
|
2004 |
2071 |
|
2005 |
2072 |
/// \brief Scaling factor for dual solution
|
2006 |
2073 |
///
|
2007 |
2074 |
/// Scaling factor for dual solution, it is equal to 4 or 1
|
2008 |
2075 |
/// according to the value type.
|
2009 |
2076 |
static const int dualScale =
|
2010 |
2077 |
std::numeric_limits<Value>::is_integer ? 4 : 1;
|
2011 |
2078 |
|
2012 |
2079 |
typedef typename Graph::template NodeMap<typename Graph::Arc>
|
2013 |
2080 |
MatchingMap;
|
2014 |
2081 |
|
2015 |
2082 |
private:
|
2016 |
2083 |
|
2017 |
2084 |
TEMPLATE_GRAPH_TYPEDEFS(Graph);
|
2018 |
2085 |
|
2019 |
2086 |
typedef typename Graph::template NodeMap<Value> NodePotential;
|
2020 |
2087 |
typedef std::vector<Node> BlossomNodeList;
|
2021 |
2088 |
|
2022 |
2089 |
struct BlossomVariable {
|
2023 |
2090 |
int begin, end;
|
2024 |
2091 |
Value value;
|
2025 |
2092 |
|
2026 |
2093 |
BlossomVariable(int _begin, int _end, Value _value)
|
2027 |
2094 |
: begin(_begin), end(_end), value(_value) {}
|
2028 |
2095 |
|
2029 |
2096 |
};
|
2030 |
2097 |
|
2031 |
2098 |
typedef std::vector<BlossomVariable> BlossomPotential;
|
2032 |
2099 |
|
2033 |
2100 |
const Graph& _graph;
|
2034 |
2101 |
const WeightMap& _weight;
|
2035 |
2102 |
|
2036 |
2103 |
MatchingMap* _matching;
|
2037 |
2104 |
|
2038 |
2105 |
NodePotential* _node_potential;
|
2039 |
2106 |
|
2040 |
2107 |
BlossomPotential _blossom_potential;
|
2041 |
2108 |
BlossomNodeList _blossom_node_list;
|
2042 |
2109 |
|
2043 |
2110 |
int _node_num;
|
2044 |
2111 |
int _blossom_num;
|
2045 |
2112 |
|
2046 |
2113 |
typedef RangeMap<int> IntIntMap;
|
2047 |
2114 |
|
2048 |
2115 |
enum Status {
|
2049 |
2116 |
EVEN = -1, MATCHED = 0, ODD = 1
|
2050 |
2117 |
};
|
2051 |
2118 |
|
2052 |
2119 |
typedef HeapUnionFind<Value, IntNodeMap> BlossomSet;
|
2053 |
2120 |
struct BlossomData {
|
2054 |
2121 |
int tree;
|
2055 |
2122 |
Status status;
|
2056 |
2123 |
Arc pred, next;
|
2057 |
2124 |
Value pot, offset;
|
2058 |
2125 |
};
|
2059 |
2126 |
|
2060 |
2127 |
IntNodeMap *_blossom_index;
|
2061 |
2128 |
BlossomSet *_blossom_set;
|
2062 |
2129 |
RangeMap<BlossomData>* _blossom_data;
|
2063 |
2130 |
|
2064 |
2131 |
IntNodeMap *_node_index;
|
2065 |
2132 |
IntArcMap *_node_heap_index;
|
2066 |
2133 |
|
2067 |
2134 |
struct NodeData {
|
2068 |
2135 |
|
2069 |
2136 |
NodeData(IntArcMap& node_heap_index)
|
2070 |
2137 |
: heap(node_heap_index) {}
|
2071 |
2138 |
|
2072 |
2139 |
int blossom;
|
2073 |
2140 |
Value pot;
|
2074 |
2141 |
BinHeap<Value, IntArcMap> heap;
|
2075 |
2142 |
std::map<int, Arc> heap_index;
|
2076 |
2143 |
|
2077 |
2144 |
int tree;
|
2078 |
2145 |
};
|
2079 |
2146 |
|
2080 |
2147 |
RangeMap<NodeData>* _node_data;
|
2081 |
2148 |
|
2082 |
2149 |
typedef ExtendFindEnum<IntIntMap> TreeSet;
|
2083 |
2150 |
|
2084 |
2151 |
IntIntMap *_tree_set_index;
|
2085 |
2152 |
TreeSet *_tree_set;
|
2086 |
2153 |
|
2087 |
2154 |
IntIntMap *_delta2_index;
|
2088 |
2155 |
BinHeap<Value, IntIntMap> *_delta2;
|
2089 |
2156 |
|
2090 |
2157 |
IntEdgeMap *_delta3_index;
|
2091 |
2158 |
BinHeap<Value, IntEdgeMap> *_delta3;
|
2092 |
2159 |
|
2093 |
2160 |
IntIntMap *_delta4_index;
|
2094 |
2161 |
BinHeap<Value, IntIntMap> *_delta4;
|
2095 |
2162 |
|
2096 |
2163 |
Value _delta_sum;
|
2097 |
2164 |
|
2098 |
2165 |
void createStructures() {
|
2099 |
2166 |
_node_num = countNodes(_graph);
|
2100 |
2167 |
_blossom_num = _node_num * 3 / 2;
|
2101 |
2168 |
|
2102 |
2169 |
if (!_matching) {
|
2103 |
2170 |
_matching = new MatchingMap(_graph);
|
2104 |
2171 |
}
|
2105 |
2172 |
if (!_node_potential) {
|
2106 |
2173 |
_node_potential = new NodePotential(_graph);
|
2107 |
2174 |
}
|
2108 |
2175 |
if (!_blossom_set) {
|
2109 |
2176 |
_blossom_index = new IntNodeMap(_graph);
|
2110 |
2177 |
_blossom_set = new BlossomSet(*_blossom_index);
|
2111 |
2178 |
_blossom_data = new RangeMap<BlossomData>(_blossom_num);
|
2112 |
2179 |
}
|
2113 |
2180 |
|
2114 |
2181 |
if (!_node_index) {
|
2115 |
2182 |
_node_index = new IntNodeMap(_graph);
|
2116 |
2183 |
_node_heap_index = new IntArcMap(_graph);
|
2117 |
2184 |
_node_data = new RangeMap<NodeData>(_node_num,
|
2118 |
2185 |
NodeData(*_node_heap_index));
|
2119 |
2186 |
}
|
2120 |
2187 |
|
2121 |
2188 |
if (!_tree_set) {
|
2122 |
2189 |
_tree_set_index = new IntIntMap(_blossom_num);
|
2123 |
2190 |
_tree_set = new TreeSet(*_tree_set_index);
|
2124 |
2191 |
}
|
2125 |
2192 |
if (!_delta2) {
|
2126 |
2193 |
_delta2_index = new IntIntMap(_blossom_num);
|
2127 |
2194 |
_delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index);
|
2128 |
2195 |
}
|
2129 |
2196 |
if (!_delta3) {
|
2130 |
2197 |
_delta3_index = new IntEdgeMap(_graph);
|
2131 |
2198 |
_delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index);
|
2132 |
2199 |
}
|
2133 |
2200 |
if (!_delta4) {
|
2134 |
2201 |
_delta4_index = new IntIntMap(_blossom_num);
|
2135 |
2202 |
_delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index);
|
2136 |
2203 |
}
|
2137 |
2204 |
}
|
2138 |
2205 |
|
2139 |
2206 |
void destroyStructures() {
|
2140 |
2207 |
_node_num = countNodes(_graph);
|
2141 |
2208 |
_blossom_num = _node_num * 3 / 2;
|
2142 |
2209 |
|
2143 |
2210 |
if (_matching) {
|
2144 |
2211 |
delete _matching;
|
2145 |
2212 |
}
|
2146 |
2213 |
if (_node_potential) {
|
2147 |
2214 |
delete _node_potential;
|
2148 |
2215 |
}
|
2149 |
2216 |
if (_blossom_set) {
|
2150 |
2217 |
delete _blossom_index;
|
2151 |
2218 |
delete _blossom_set;
|
2152 |
2219 |
delete _blossom_data;
|
2153 |
2220 |
}
|
2154 |
2221 |
|
2155 |
2222 |
if (_node_index) {
|
2156 |
2223 |
delete _node_index;
|
2157 |
2224 |
delete _node_heap_index;
|
2158 |
2225 |
delete _node_data;
|
2159 |
2226 |
}
|
2160 |
2227 |
|
2161 |
2228 |
if (_tree_set) {
|
2162 |
2229 |
delete _tree_set_index;
|
2163 |
2230 |
delete _tree_set;
|
2164 |
2231 |
}
|
2165 |
2232 |
if (_delta2) {
|
2166 |
2233 |
delete _delta2_index;
|
2167 |
2234 |
delete _delta2;
|
2168 |
2235 |
}
|
2169 |
2236 |
if (_delta3) {
|
2170 |
2237 |
delete _delta3_index;
|
2171 |
2238 |
delete _delta3;
|
2172 |
2239 |
}
|
2173 |
2240 |
if (_delta4) {
|
2174 |
2241 |
delete _delta4_index;
|
2175 |
2242 |
delete _delta4;
|
2176 |
2243 |
}
|
2177 |
2244 |
}
|
2178 |
2245 |
|
2179 |
2246 |
void matchedToEven(int blossom, int tree) {
|
2180 |
2247 |
if (_delta2->state(blossom) == _delta2->IN_HEAP) {
|
2181 |
2248 |
_delta2->erase(blossom);
|
2182 |
2249 |
}
|
2183 |
2250 |
|
2184 |
2251 |
if (!_blossom_set->trivial(blossom)) {
|
2185 |
2252 |
(*_blossom_data)[blossom].pot -=
|
2186 |
2253 |
2 * (_delta_sum - (*_blossom_data)[blossom].offset);
|
2187 |
2254 |
}
|
2188 |
2255 |
|
2189 |
2256 |
for (typename BlossomSet::ItemIt n(*_blossom_set, blossom);
|
2190 |
2257 |
n != INVALID; ++n) {
|
2191 |
2258 |
|
2192 |
2259 |
_blossom_set->increase(n, std::numeric_limits<Value>::max());
|
2193 |
2260 |
int ni = (*_node_index)[n];
|
2194 |
2261 |
|
... |
... |
@@ -2629,479 +2696,512 @@
|
2629 |
2696 |
Arc next = (*_blossom_data)[blossom].next;
|
2630 |
2697 |
Arc pred = (*_blossom_data)[blossom].pred;
|
2631 |
2698 |
|
2632 |
2699 |
int tree = _tree_set->find(blossom);
|
2633 |
2700 |
|
2634 |
2701 |
(*_blossom_data)[blossom].status = MATCHED;
|
2635 |
2702 |
oddToMatched(blossom);
|
2636 |
2703 |
if (_delta2->state(blossom) == _delta2->IN_HEAP) {
|
2637 |
2704 |
_delta2->erase(blossom);
|
2638 |
2705 |
}
|
2639 |
2706 |
|
2640 |
2707 |
std::vector<int> subblossoms;
|
2641 |
2708 |
_blossom_set->split(blossom, std::back_inserter(subblossoms));
|
2642 |
2709 |
|
2643 |
2710 |
Value offset = (*_blossom_data)[blossom].offset;
|
2644 |
2711 |
int b = _blossom_set->find(_graph.source(pred));
|
2645 |
2712 |
int d = _blossom_set->find(_graph.source(next));
|
2646 |
2713 |
|
2647 |
2714 |
int ib = -1, id = -1;
|
2648 |
2715 |
for (int i = 0; i < int(subblossoms.size()); ++i) {
|
2649 |
2716 |
if (subblossoms[i] == b) ib = i;
|
2650 |
2717 |
if (subblossoms[i] == d) id = i;
|
2651 |
2718 |
|
2652 |
2719 |
(*_blossom_data)[subblossoms[i]].offset = offset;
|
2653 |
2720 |
if (!_blossom_set->trivial(subblossoms[i])) {
|
2654 |
2721 |
(*_blossom_data)[subblossoms[i]].pot -= 2 * offset;
|
2655 |
2722 |
}
|
2656 |
2723 |
if (_blossom_set->classPrio(subblossoms[i]) !=
|
2657 |
2724 |
std::numeric_limits<Value>::max()) {
|
2658 |
2725 |
_delta2->push(subblossoms[i],
|
2659 |
2726 |
_blossom_set->classPrio(subblossoms[i]) -
|
2660 |
2727 |
(*_blossom_data)[subblossoms[i]].offset);
|
2661 |
2728 |
}
|
2662 |
2729 |
}
|
2663 |
2730 |
|
2664 |
2731 |
if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) {
|
2665 |
2732 |
for (int i = (id + 1) % subblossoms.size();
|
2666 |
2733 |
i != ib; i = (i + 2) % subblossoms.size()) {
|
2667 |
2734 |
int sb = subblossoms[i];
|
2668 |
2735 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
2669 |
2736 |
(*_blossom_data)[sb].next =
|
2670 |
2737 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
2671 |
2738 |
}
|
2672 |
2739 |
|
2673 |
2740 |
for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) {
|
2674 |
2741 |
int sb = subblossoms[i];
|
2675 |
2742 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
2676 |
2743 |
int ub = subblossoms[(i + 2) % subblossoms.size()];
|
2677 |
2744 |
|
2678 |
2745 |
(*_blossom_data)[sb].status = ODD;
|
2679 |
2746 |
matchedToOdd(sb);
|
2680 |
2747 |
_tree_set->insert(sb, tree);
|
2681 |
2748 |
(*_blossom_data)[sb].pred = pred;
|
2682 |
2749 |
(*_blossom_data)[sb].next =
|
2683 |
2750 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
2684 |
2751 |
|
2685 |
2752 |
pred = (*_blossom_data)[ub].next;
|
2686 |
2753 |
|
2687 |
2754 |
(*_blossom_data)[tb].status = EVEN;
|
2688 |
2755 |
matchedToEven(tb, tree);
|
2689 |
2756 |
_tree_set->insert(tb, tree);
|
2690 |
2757 |
(*_blossom_data)[tb].pred = (*_blossom_data)[tb].next;
|
2691 |
2758 |
}
|
2692 |
2759 |
|
2693 |
2760 |
(*_blossom_data)[subblossoms[id]].status = ODD;
|
2694 |
2761 |
matchedToOdd(subblossoms[id]);
|
2695 |
2762 |
_tree_set->insert(subblossoms[id], tree);
|
2696 |
2763 |
(*_blossom_data)[subblossoms[id]].next = next;
|
2697 |
2764 |
(*_blossom_data)[subblossoms[id]].pred = pred;
|
2698 |
2765 |
|
2699 |
2766 |
} else {
|
2700 |
2767 |
|
2701 |
2768 |
for (int i = (ib + 1) % subblossoms.size();
|
2702 |
2769 |
i != id; i = (i + 2) % subblossoms.size()) {
|
2703 |
2770 |
int sb = subblossoms[i];
|
2704 |
2771 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
2705 |
2772 |
(*_blossom_data)[sb].next =
|
2706 |
2773 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
2707 |
2774 |
}
|
2708 |
2775 |
|
2709 |
2776 |
for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) {
|
2710 |
2777 |
int sb = subblossoms[i];
|
2711 |
2778 |
int tb = subblossoms[(i + 1) % subblossoms.size()];
|
2712 |
2779 |
int ub = subblossoms[(i + 2) % subblossoms.size()];
|
2713 |
2780 |
|
2714 |
2781 |
(*_blossom_data)[sb].status = ODD;
|
2715 |
2782 |
matchedToOdd(sb);
|
2716 |
2783 |
_tree_set->insert(sb, tree);
|
2717 |
2784 |
(*_blossom_data)[sb].next = next;
|
2718 |
2785 |
(*_blossom_data)[sb].pred =
|
2719 |
2786 |
_graph.oppositeArc((*_blossom_data)[tb].next);
|
2720 |
2787 |
|
2721 |
2788 |
(*_blossom_data)[tb].status = EVEN;
|
2722 |
2789 |
matchedToEven(tb, tree);
|
2723 |
2790 |
_tree_set->insert(tb, tree);
|
2724 |
2791 |
(*_blossom_data)[tb].pred =
|
2725 |
2792 |
(*_blossom_data)[tb].next =
|
2726 |
2793 |
_graph.oppositeArc((*_blossom_data)[ub].next);
|
2727 |
2794 |
next = (*_blossom_data)[ub].next;
|
2728 |
2795 |
}
|
2729 |
2796 |
|
2730 |
2797 |
(*_blossom_data)[subblossoms[ib]].status = ODD;
|
2731 |
2798 |
matchedToOdd(subblossoms[ib]);
|
2732 |
2799 |
_tree_set->insert(subblossoms[ib], tree);
|
2733 |
2800 |
(*_blossom_data)[subblossoms[ib]].next = next;
|
2734 |
2801 |
(*_blossom_data)[subblossoms[ib]].pred = pred;
|
2735 |
2802 |
}
|
2736 |
2803 |
_tree_set->erase(blossom);
|
2737 |
2804 |
}
|
2738 |
2805 |
|
2739 |
2806 |
void extractBlossom(int blossom, const Node& base, const Arc& matching) {
|
2740 |
2807 |
if (_blossom_set->trivial(blossom)) {
|
2741 |
2808 |
int bi = (*_node_index)[base];
|
2742 |
2809 |
Value pot = (*_node_data)[bi].pot;
|
2743 |
2810 |
|
2744 |
2811 |
(*_matching)[base] = matching;
|
2745 |
2812 |
_blossom_node_list.push_back(base);
|
2746 |
2813 |
(*_node_potential)[base] = pot;
|
2747 |
2814 |
} else {
|
2748 |
2815 |
|
2749 |
2816 |
Value pot = (*_blossom_data)[blossom].pot;
|
2750 |
2817 |
int bn = _blossom_node_list.size();
|
2751 |
2818 |
|
2752 |
2819 |
std::vector<int> subblossoms;
|
2753 |
2820 |
_blossom_set->split(blossom, std::back_inserter(subblossoms));
|
2754 |
2821 |
int b = _blossom_set->find(base);
|
2755 |
2822 |
int ib = -1;
|
2756 |
2823 |
for (int i = 0; i < int(subblossoms.size()); ++i) {
|
2757 |
2824 |
if (subblossoms[i] == b) { ib = i; break; }
|
2758 |
2825 |
}
|
2759 |
2826 |
|
2760 |
2827 |
for (int i = 1; i < int(subblossoms.size()); i += 2) {
|
2761 |
2828 |
int sb = subblossoms[(ib + i) % subblossoms.size()];
|
2762 |
2829 |
int tb = subblossoms[(ib + i + 1) % subblossoms.size()];
|
2763 |
2830 |
|
2764 |
2831 |
Arc m = (*_blossom_data)[tb].next;
|
2765 |
2832 |
extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m));
|
2766 |
2833 |
extractBlossom(tb, _graph.source(m), m);
|
2767 |
2834 |
}
|
2768 |
2835 |
extractBlossom(subblossoms[ib], base, matching);
|
2769 |
2836 |
|
2770 |
2837 |
int en = _blossom_node_list.size();
|
2771 |
2838 |
|
2772 |
2839 |
_blossom_potential.push_back(BlossomVariable(bn, en, pot));
|
2773 |
2840 |
}
|
2774 |
2841 |
}
|
2775 |
2842 |
|
2776 |
2843 |
void extractMatching() {
|
2777 |
2844 |
std::vector<int> blossoms;
|
2778 |
2845 |
for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) {
|
2779 |
2846 |
blossoms.push_back(c);
|
2780 |
2847 |
}
|
2781 |
2848 |
|
2782 |
2849 |
for (int i = 0; i < int(blossoms.size()); ++i) {
|
2783 |
2850 |
|
2784 |
2851 |
Value offset = (*_blossom_data)[blossoms[i]].offset;
|
2785 |
2852 |
(*_blossom_data)[blossoms[i]].pot += 2 * offset;
|
2786 |
2853 |
for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]);
|
2787 |
2854 |
n != INVALID; ++n) {
|
2788 |
2855 |
(*_node_data)[(*_node_index)[n]].pot -= offset;
|
2789 |
2856 |
}
|
2790 |
2857 |
|
2791 |
2858 |
Arc matching = (*_blossom_data)[blossoms[i]].next;
|
2792 |
2859 |
Node base = _graph.source(matching);
|
2793 |
2860 |
extractBlossom(blossoms[i], base, matching);
|
2794 |
2861 |
}
|
2795 |
2862 |
}
|
2796 |
2863 |
|
2797 |
2864 |
public:
|
2798 |
2865 |
|
2799 |
2866 |
/// \brief Constructor
|
2800 |
2867 |
///
|
2801 |
2868 |
/// Constructor.
|
2802 |
2869 |
MaxWeightedPerfectMatching(const Graph& graph, const WeightMap& weight)
|
2803 |
2870 |
: _graph(graph), _weight(weight), _matching(0),
|
2804 |
2871 |
_node_potential(0), _blossom_potential(), _blossom_node_list(),
|
2805 |
2872 |
_node_num(0), _blossom_num(0),
|
2806 |
2873 |
|
2807 |
2874 |
_blossom_index(0), _blossom_set(0), _blossom_data(0),
|
2808 |
2875 |
_node_index(0), _node_heap_index(0), _node_data(0),
|
2809 |
2876 |
_tree_set_index(0), _tree_set(0),
|
2810 |
2877 |
|
2811 |
2878 |
_delta2_index(0), _delta2(0),
|
2812 |
2879 |
_delta3_index(0), _delta3(0),
|
2813 |
2880 |
_delta4_index(0), _delta4(0),
|
2814 |
2881 |
|
2815 |
2882 |
_delta_sum() {}
|
2816 |
2883 |
|
2817 |
2884 |
~MaxWeightedPerfectMatching() {
|
2818 |
2885 |
destroyStructures();
|
2819 |
2886 |
}
|
2820 |
2887 |
|
2821 |
|
/// \name Execution control
|
|
2888 |
/// \name Execution Control
|
2822 |
2889 |
/// The simplest way to execute the algorithm is to use the
|
2823 |
|
/// \c run() member function.
|
|
2890 |
/// \ref run() member function.
|
2824 |
2891 |
|
2825 |
2892 |
///@{
|
2826 |
2893 |
|
2827 |
2894 |
/// \brief Initialize the algorithm
|
2828 |
2895 |
///
|
2829 |
|
/// Initialize the algorithm
|
|
2896 |
/// This function initializes the algorithm.
|
2830 |
2897 |
void init() {
|
2831 |
2898 |
createStructures();
|
2832 |
2899 |
|
2833 |
2900 |
for (ArcIt e(_graph); e != INVALID; ++e) {
|
2834 |
2901 |
(*_node_heap_index)[e] = BinHeap<Value, IntArcMap>::PRE_HEAP;
|
2835 |
2902 |
}
|
2836 |
2903 |
for (EdgeIt e(_graph); e != INVALID; ++e) {
|
2837 |
2904 |
(*_delta3_index)[e] = _delta3->PRE_HEAP;
|
2838 |
2905 |
}
|
2839 |
2906 |
for (int i = 0; i < _blossom_num; ++i) {
|
2840 |
2907 |
(*_delta2_index)[i] = _delta2->PRE_HEAP;
|
2841 |
2908 |
(*_delta4_index)[i] = _delta4->PRE_HEAP;
|
2842 |
2909 |
}
|
2843 |
2910 |
|
2844 |
2911 |
int index = 0;
|
2845 |
2912 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
2846 |
2913 |
Value max = - std::numeric_limits<Value>::max();
|
2847 |
2914 |
for (OutArcIt e(_graph, n); e != INVALID; ++e) {
|
2848 |
2915 |
if (_graph.target(e) == n) continue;
|
2849 |
2916 |
if ((dualScale * _weight[e]) / 2 > max) {
|
2850 |
2917 |
max = (dualScale * _weight[e]) / 2;
|
2851 |
2918 |
}
|
2852 |
2919 |
}
|
2853 |
2920 |
(*_node_index)[n] = index;
|
2854 |
2921 |
(*_node_data)[index].pot = max;
|
2855 |
2922 |
int blossom =
|
2856 |
2923 |
_blossom_set->insert(n, std::numeric_limits<Value>::max());
|
2857 |
2924 |
|
2858 |
2925 |
_tree_set->insert(blossom);
|
2859 |
2926 |
|
2860 |
2927 |
(*_blossom_data)[blossom].status = EVEN;
|
2861 |
2928 |
(*_blossom_data)[blossom].pred = INVALID;
|
2862 |
2929 |
(*_blossom_data)[blossom].next = INVALID;
|
2863 |
2930 |
(*_blossom_data)[blossom].pot = 0;
|
2864 |
2931 |
(*_blossom_data)[blossom].offset = 0;
|
2865 |
2932 |
++index;
|
2866 |
2933 |
}
|
2867 |
2934 |
for (EdgeIt e(_graph); e != INVALID; ++e) {
|
2868 |
2935 |
int si = (*_node_index)[_graph.u(e)];
|
2869 |
2936 |
int ti = (*_node_index)[_graph.v(e)];
|
2870 |
2937 |
if (_graph.u(e) != _graph.v(e)) {
|
2871 |
2938 |
_delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot -
|
2872 |
2939 |
dualScale * _weight[e]) / 2);
|
2873 |
2940 |
}
|
2874 |
2941 |
}
|
2875 |
2942 |
}
|
2876 |
2943 |
|
2877 |
|
/// \brief Starts the algorithm
|
|
2944 |
/// \brief Start the algorithm
|
2878 |
2945 |
///
|
2879 |
|
/// Starts the algorithm
|
|
2946 |
/// This function starts the algorithm.
|
|
2947 |
///
|
|
2948 |
/// \pre \ref init() must be called before using this function.
|
2880 |
2949 |
bool start() {
|
2881 |
2950 |
enum OpType {
|
2882 |
2951 |
D2, D3, D4
|
2883 |
2952 |
};
|
2884 |
2953 |
|
2885 |
2954 |
int unmatched = _node_num;
|
2886 |
2955 |
while (unmatched > 0) {
|
2887 |
2956 |
Value d2 = !_delta2->empty() ?
|
2888 |
2957 |
_delta2->prio() : std::numeric_limits<Value>::max();
|
2889 |
2958 |
|
2890 |
2959 |
Value d3 = !_delta3->empty() ?
|
2891 |
2960 |
_delta3->prio() : std::numeric_limits<Value>::max();
|
2892 |
2961 |
|
2893 |
2962 |
Value d4 = !_delta4->empty() ?
|
2894 |
2963 |
_delta4->prio() : std::numeric_limits<Value>::max();
|
2895 |
2964 |
|
2896 |
2965 |
_delta_sum = d2; OpType ot = D2;
|
2897 |
2966 |
if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; }
|
2898 |
2967 |
if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; }
|
2899 |
2968 |
|
2900 |
2969 |
if (_delta_sum == std::numeric_limits<Value>::max()) {
|
2901 |
2970 |
return false;
|
2902 |
2971 |
}
|
2903 |
2972 |
|
2904 |
2973 |
switch (ot) {
|
2905 |
2974 |
case D2:
|
2906 |
2975 |
{
|
2907 |
2976 |
int blossom = _delta2->top();
|
2908 |
2977 |
Node n = _blossom_set->classTop(blossom);
|
2909 |
2978 |
Arc e = (*_node_data)[(*_node_index)[n]].heap.top();
|
2910 |
2979 |
extendOnArc(e);
|
2911 |
2980 |
}
|
2912 |
2981 |
break;
|
2913 |
2982 |
case D3:
|
2914 |
2983 |
{
|
2915 |
2984 |
Edge e = _delta3->top();
|
2916 |
2985 |
|
2917 |
2986 |
int left_blossom = _blossom_set->find(_graph.u(e));
|
2918 |
2987 |
int right_blossom = _blossom_set->find(_graph.v(e));
|
2919 |
2988 |
|
2920 |
2989 |
if (left_blossom == right_blossom) {
|
2921 |
2990 |
_delta3->pop();
|
2922 |
2991 |
} else {
|
2923 |
2992 |
int left_tree = _tree_set->find(left_blossom);
|
2924 |
2993 |
int right_tree = _tree_set->find(right_blossom);
|
2925 |
2994 |
|
2926 |
2995 |
if (left_tree == right_tree) {
|
2927 |
2996 |
shrinkOnEdge(e, left_tree);
|
2928 |
2997 |
} else {
|
2929 |
2998 |
augmentOnEdge(e);
|
2930 |
2999 |
unmatched -= 2;
|
2931 |
3000 |
}
|
2932 |
3001 |
}
|
2933 |
3002 |
} break;
|
2934 |
3003 |
case D4:
|
2935 |
3004 |
splitBlossom(_delta4->top());
|
2936 |
3005 |
break;
|
2937 |
3006 |
}
|
2938 |
3007 |
}
|
2939 |
3008 |
extractMatching();
|
2940 |
3009 |
return true;
|
2941 |
3010 |
}
|
2942 |
3011 |
|
2943 |
|
/// \brief Runs %MaxWeightedPerfectMatching algorithm.
|
|
3012 |
/// \brief Run the algorithm.
|
2944 |
3013 |
///
|
2945 |
|
/// This method runs the %MaxWeightedPerfectMatching algorithm.
|
|
3014 |
/// This method runs the \c %MaxWeightedPerfectMatching algorithm.
|
2946 |
3015 |
///
|
2947 |
|
/// \note mwm.run() is just a shortcut of the following code.
|
|
3016 |
/// \note mwpm.run() is just a shortcut of the following code.
|
2948 |
3017 |
/// \code
|
2949 |
|
/// mwm.init();
|
2950 |
|
/// mwm.start();
|
|
3018 |
/// mwpm.init();
|
|
3019 |
/// mwpm.start();
|
2951 |
3020 |
/// \endcode
|
2952 |
3021 |
bool run() {
|
2953 |
3022 |
init();
|
2954 |
3023 |
return start();
|
2955 |
3024 |
}
|
2956 |
3025 |
|
2957 |
3026 |
/// @}
|
2958 |
3027 |
|
2959 |
|
/// \name Primal solution
|
2960 |
|
/// Functions to get the primal solution, ie. the matching.
|
|
3028 |
/// \name Primal Solution
|
|
3029 |
/// Functions to get the primal solution, i.e. the maximum weighted
|
|
3030 |
/// perfect matching.\n
|
|
3031 |
/// Either \ref run() or \ref start() function should be called before
|
|
3032 |
/// using them.
|
2961 |
3033 |
|
2962 |
3034 |
/// @{
|
2963 |
3035 |
|
2964 |
|
/// \brief Returns the matching value.
|
|
3036 |
/// \brief Return the weight of the matching.
|
2965 |
3037 |
///
|
2966 |
|
/// Returns the matching value.
|
|
3038 |
/// This function returns the weight of the found matching.
|
|
3039 |
///
|
|
3040 |
/// \pre Either run() or start() must be called before using this function.
|
2967 |
3041 |
Value matchingValue() const {
|
2968 |
3042 |
Value sum = 0;
|
2969 |
3043 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
2970 |
3044 |
if ((*_matching)[n] != INVALID) {
|
2971 |
3045 |
sum += _weight[(*_matching)[n]];
|
2972 |
3046 |
}
|
2973 |
3047 |
}
|
2974 |
3048 |
return sum /= 2;
|
2975 |
3049 |
}
|
2976 |
3050 |
|
2977 |
|
/// \brief Returns true when the edge is in the matching.
|
|
3051 |
/// \brief Return \c true if the given edge is in the matching.
|
2978 |
3052 |
///
|
2979 |
|
/// Returns true when the edge is in the matching.
|
|
3053 |
/// This function returns \c true if the given edge is in the found
|
|
3054 |
/// matching.
|
|
3055 |
///
|
|
3056 |
/// \pre Either run() or start() must be called before using this function.
|
2980 |
3057 |
bool matching(const Edge& edge) const {
|
2981 |
3058 |
return static_cast<const Edge&>((*_matching)[_graph.u(edge)]) == edge;
|
2982 |
3059 |
}
|
2983 |
3060 |
|
2984 |
|
/// \brief Returns the incident matching edge.
|
|
3061 |
/// \brief Return the matching arc (or edge) incident to the given node.
|
2985 |
3062 |
///
|
2986 |
|
/// Returns the incident matching arc from given edge.
|
|
3063 |
/// This function returns the matching arc (or edge) incident to the
|
|
3064 |
/// given node in the found matching or \c INVALID if the node is
|
|
3065 |
/// not covered by the matching.
|
|
3066 |
///
|
|
3067 |
/// \pre Either run() or start() must be called before using this function.
|
2987 |
3068 |
Arc matching(const Node& node) const {
|
2988 |
3069 |
return (*_matching)[node];
|
2989 |
3070 |
}
|
2990 |
3071 |
|
2991 |
|
/// \brief Returns the mate of the node.
|
|
3072 |
/// \brief Return the mate of the given node.
|
2992 |
3073 |
///
|
2993 |
|
/// Returns the adjancent node in a mathcing arc.
|
|
3074 |
/// This function returns the mate of the given node in the found
|
|
3075 |
/// matching or \c INVALID if the node is not covered by the matching.
|
|
3076 |
///
|
|
3077 |
/// \pre Either run() or start() must be called before using this function.
|
2994 |
3078 |
Node mate(const Node& node) const {
|
2995 |
3079 |
return _graph.target((*_matching)[node]);
|
2996 |
3080 |
}
|
2997 |
3081 |
|
2998 |
3082 |
/// @}
|
2999 |
3083 |
|
3000 |
|
/// \name Dual solution
|
3001 |
|
/// Functions to get the dual solution.
|
|
3084 |
/// \name Dual Solution
|
|
3085 |
/// Functions to get the dual solution.\n
|
|
3086 |
/// Either \ref run() or \ref start() function should be called before
|
|
3087 |
/// using them.
|
3002 |
3088 |
|
3003 |
3089 |
/// @{
|
3004 |
3090 |
|
3005 |
|
/// \brief Returns the value of the dual solution.
|
|
3091 |
/// \brief Return the value of the dual solution.
|
3006 |
3092 |
///
|
3007 |
|
/// Returns the value of the dual solution. It should be equal to
|
3008 |
|
/// the primal value scaled by \ref dualScale "dual scale".
|
|
3093 |
/// This function returns the value of the dual solution.
|
|
3094 |
/// It should be equal to the primal value scaled by \ref dualScale
|
|
3095 |
/// "dual scale".
|
|
3096 |
///
|
|
3097 |
/// \pre Either run() or start() must be called before using this function.
|
3009 |
3098 |
Value dualValue() const {
|
3010 |
3099 |
Value sum = 0;
|
3011 |
3100 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
3012 |
3101 |
sum += nodeValue(n);
|
3013 |
3102 |
}
|
3014 |
3103 |
for (int i = 0; i < blossomNum(); ++i) {
|
3015 |
3104 |
sum += blossomValue(i) * (blossomSize(i) / 2);
|
3016 |
3105 |
}
|
3017 |
3106 |
return sum;
|
3018 |
3107 |
}
|
3019 |
3108 |
|
3020 |
|
/// \brief Returns the value of the node.
|
|
3109 |
/// \brief Return the dual value (potential) of the given node.
|
3021 |
3110 |
///
|
3022 |
|
/// Returns the the value of the node.
|
|
3111 |
/// This function returns the dual value (potential) of the given node.
|
|
3112 |
///
|
|
3113 |
/// \pre Either run() or start() must be called before using this function.
|
3023 |
3114 |
Value nodeValue(const Node& n) const {
|
3024 |
3115 |
return (*_node_potential)[n];
|
3025 |
3116 |
}
|
3026 |
3117 |
|
3027 |
|
/// \brief Returns the number of the blossoms in the basis.
|
|
3118 |
/// \brief Return the number of the blossoms in the basis.
|
3028 |
3119 |
///
|
3029 |
|
/// Returns the number of the blossoms in the basis.
|
|
3120 |
/// This function returns the number of the blossoms in the basis.
|
|
3121 |
///
|
|
3122 |
/// \pre Either run() or start() must be called before using this function.
|
3030 |
3123 |
/// \see BlossomIt
|
3031 |
3124 |
int blossomNum() const {
|
3032 |
3125 |
return _blossom_potential.size();
|
3033 |
3126 |
}
|
3034 |
3127 |
|
3035 |
|
|
3036 |
|
/// \brief Returns the number of the nodes in the blossom.
|
|
3128 |
/// \brief Return the number of the nodes in the given blossom.
|
3037 |
3129 |
///
|
3038 |
|
/// Returns the number of the nodes in the blossom.
|
|
3130 |
/// This function returns the number of the nodes in the given blossom.
|
|
3131 |
///
|
|
3132 |
/// \pre Either run() or start() must be called before using this function.
|
|
3133 |
/// \see BlossomIt
|
3039 |
3134 |
int blossomSize(int k) const {
|
3040 |
3135 |
return _blossom_potential[k].end - _blossom_potential[k].begin;
|
3041 |
3136 |
}
|
3042 |
3137 |
|
3043 |
|
/// \brief Returns the value of the blossom.
|
|
3138 |
/// \brief Return the dual value (ptential) of the given blossom.
|
3044 |
3139 |
///
|
3045 |
|
/// Returns the the value of the blossom.
|
3046 |
|
/// \see BlossomIt
|
|
3140 |
/// This function returns the dual value (ptential) of the given blossom.
|
|
3141 |
///
|
|
3142 |
/// \pre Either run() or start() must be called before using this function.
|
3047 |
3143 |
Value blossomValue(int k) const {
|
3048 |
3144 |
return _blossom_potential[k].value;
|
3049 |
3145 |
}
|
3050 |
3146 |
|
3051 |
|
/// \brief Iterator for obtaining the nodes of the blossom.
|
|
3147 |
/// \brief Iterator for obtaining the nodes of a blossom.
|
3052 |
3148 |
///
|
3053 |
|
/// Iterator for obtaining the nodes of the blossom. This class
|
3054 |
|
/// provides a common lemon style iterator for listing a
|
3055 |
|
/// subset of the nodes.
|
|
3149 |
/// This class provides an iterator for obtaining the nodes of the
|
|
3150 |
/// given blossom. It lists a subset of the nodes.
|
|
3151 |
/// Before using this iterator, you must allocate a
|
|
3152 |
/// MaxWeightedPerfectMatching class and execute it.
|
3056 |
3153 |
class BlossomIt {
|
3057 |
3154 |
public:
|
3058 |
3155 |
|
3059 |
3156 |
/// \brief Constructor.
|
3060 |
3157 |
///
|
3061 |
|
/// Constructor to get the nodes of the variable.
|
|
3158 |
/// Constructor to get the nodes of the given variable.
|
|
3159 |
///
|
|
3160 |
/// \pre Either \ref MaxWeightedPerfectMatching::run() "algorithm.run()"
|
|
3161 |
/// or \ref MaxWeightedPerfectMatching::start() "algorithm.start()"
|
|
3162 |
/// must be called before initializing this iterator.
|
3062 |
3163 |
BlossomIt(const MaxWeightedPerfectMatching& algorithm, int variable)
|
3063 |
3164 |
: _algorithm(&algorithm)
|
3064 |
3165 |
{
|
3065 |
3166 |
_index = _algorithm->_blossom_potential[variable].begin;
|
3066 |
3167 |
_last = _algorithm->_blossom_potential[variable].end;
|
3067 |
3168 |
}
|
3068 |
3169 |
|
3069 |
|
/// \brief Conversion to node.
|
|
3170 |
/// \brief Conversion to \c Node.
|
3070 |
3171 |
///
|
3071 |
|
/// Conversion to node.
|
|
3172 |
/// Conversion to \c Node.
|
3072 |
3173 |
operator Node() const {
|
3073 |
3174 |
return _algorithm->_blossom_node_list[_index];
|
3074 |
3175 |
}
|
3075 |
3176 |
|
3076 |
3177 |
/// \brief Increment operator.
|
3077 |
3178 |
///
|
3078 |
3179 |
/// Increment operator.
|
3079 |
3180 |
BlossomIt& operator++() {
|
3080 |
3181 |
++_index;
|
3081 |
3182 |
return *this;
|
3082 |
3183 |
}
|
3083 |
3184 |
|
3084 |
3185 |
/// \brief Validity checking
|
3085 |
3186 |
///
|
3086 |
|
/// Checks whether the iterator is invalid.
|
|
3187 |
/// This function checks whether the iterator is invalid.
|
3087 |
3188 |
bool operator==(Invalid) const { return _index == _last; }
|
3088 |
3189 |
|
3089 |
3190 |
/// \brief Validity checking
|
3090 |
3191 |
///
|
3091 |
|
/// Checks whether the iterator is valid.
|
|
3192 |
/// This function checks whether the iterator is valid.
|
3092 |
3193 |
bool operator!=(Invalid) const { return _index != _last; }
|
3093 |
3194 |
|
3094 |
3195 |
private:
|
3095 |
3196 |
const MaxWeightedPerfectMatching* _algorithm;
|
3096 |
3197 |
int _last;
|
3097 |
3198 |
int _index;
|
3098 |
3199 |
};
|
3099 |
3200 |
|
3100 |
3201 |
/// @}
|
3101 |
3202 |
|
3102 |
3203 |
};
|
3103 |
3204 |
|
3104 |
|
|
3105 |
3205 |
} //END OF NAMESPACE LEMON
|
3106 |
3206 |
|
3107 |
3207 |
#endif //LEMON_MAX_MATCHING_H
|