1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library. |
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4 | * |
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5 | * Copyright (C) 2003-2009 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_MAX_MATCHING_H |
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20 | #define LEMON_MAX_MATCHING_H |
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21 | |
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22 | #include <vector> |
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23 | #include <queue> |
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24 | #include <set> |
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25 | #include <limits> |
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26 | |
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27 | #include <lemon/core.h> |
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28 | #include <lemon/unionfind.h> |
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29 | #include <lemon/bin_heap.h> |
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30 | #include <lemon/maps.h> |
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31 | |
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32 | ///\ingroup matching |
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33 | ///\file |
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34 | ///\brief Maximum matching algorithms in general graphs. |
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35 | |
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36 | namespace lemon { |
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37 | |
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38 | /// \ingroup matching |
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39 | /// |
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40 | /// \brief Maximum cardinality matching in general graphs |
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41 | /// |
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42 | /// This class implements Edmonds' alternating forest matching algorithm |
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43 | /// for finding a maximum cardinality matching in a general graph. |
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44 | /// It can be started from an arbitrary initial matching |
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45 | /// (the default is the empty one). |
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46 | /// |
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47 | /// The dual solution of the problem is a map of the nodes to |
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48 | /// \ref MaxMatching::Status "Status", having values \c EVEN (or \c D), |
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49 | /// \c ODD (or \c A) and \c MATCHED (or \c C) defining the Gallai-Edmonds |
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50 | /// decomposition of the graph. The nodes in \c EVEN/D induce a subgraph |
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51 | /// with factor-critical components, the nodes in \c ODD/A form the |
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52 | /// canonical barrier, and the nodes in \c MATCHED/C induce a graph having |
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53 | /// a perfect matching. The number of the factor-critical components |
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54 | /// minus the number of barrier nodes is a lower bound on the |
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55 | /// unmatched nodes, and the matching is optimal if and only if this bound is |
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56 | /// tight. This decomposition can be obtained by calling \c |
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57 | /// decomposition() after running the algorithm. |
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58 | /// |
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59 | /// \tparam GR The graph type the algorithm runs on. |
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60 | template <typename GR> |
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61 | class MaxMatching { |
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62 | public: |
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63 | |
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64 | /// The graph type of the algorithm |
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65 | typedef GR Graph; |
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66 | typedef typename Graph::template NodeMap<typename Graph::Arc> |
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67 | MatchingMap; |
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68 | |
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69 | ///\brief Status constants for Gallai-Edmonds decomposition. |
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70 | /// |
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71 | ///These constants are used for indicating the Gallai-Edmonds |
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72 | ///decomposition of a graph. The nodes with status \c EVEN (or \c D) |
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73 | ///induce a subgraph with factor-critical components, the nodes with |
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74 | ///status \c ODD (or \c A) form the canonical barrier, and the nodes |
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75 | ///with status \c MATCHED (or \c C) induce a subgraph having a |
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76 | ///perfect matching. |
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77 | enum Status { |
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78 | EVEN = 1, ///< = 1. (\c D is an alias for \c EVEN.) |
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79 | D = 1, |
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80 | MATCHED = 0, ///< = 0. (\c C is an alias for \c MATCHED.) |
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81 | C = 0, |
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82 | ODD = -1, ///< = -1. (\c A is an alias for \c ODD.) |
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83 | A = -1, |
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84 | UNMATCHED = -2 ///< = -2. |
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85 | }; |
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86 | |
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87 | typedef typename Graph::template NodeMap<Status> StatusMap; |
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88 | |
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89 | private: |
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90 | |
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91 | TEMPLATE_GRAPH_TYPEDEFS(Graph); |
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92 | |
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93 | typedef UnionFindEnum<IntNodeMap> BlossomSet; |
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94 | typedef ExtendFindEnum<IntNodeMap> TreeSet; |
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95 | typedef RangeMap<Node> NodeIntMap; |
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96 | typedef MatchingMap EarMap; |
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97 | typedef std::vector<Node> NodeQueue; |
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98 | |
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99 | const Graph& _graph; |
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100 | MatchingMap* _matching; |
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101 | StatusMap* _status; |
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102 | |
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103 | EarMap* _ear; |
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104 | |
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105 | IntNodeMap* _blossom_set_index; |
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106 | BlossomSet* _blossom_set; |
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107 | NodeIntMap* _blossom_rep; |
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108 | |
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109 | IntNodeMap* _tree_set_index; |
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110 | TreeSet* _tree_set; |
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111 | |
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112 | NodeQueue _node_queue; |
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113 | int _process, _postpone, _last; |
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114 | |
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115 | int _node_num; |
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116 | |
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117 | private: |
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118 | |
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119 | void createStructures() { |
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120 | _node_num = countNodes(_graph); |
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121 | if (!_matching) { |
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122 | _matching = new MatchingMap(_graph); |
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123 | } |
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124 | if (!_status) { |
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125 | _status = new StatusMap(_graph); |
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126 | } |
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127 | if (!_ear) { |
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128 | _ear = new EarMap(_graph); |
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129 | } |
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130 | if (!_blossom_set) { |
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131 | _blossom_set_index = new IntNodeMap(_graph); |
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132 | _blossom_set = new BlossomSet(*_blossom_set_index); |
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133 | } |
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134 | if (!_blossom_rep) { |
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135 | _blossom_rep = new NodeIntMap(_node_num); |
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136 | } |
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137 | if (!_tree_set) { |
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138 | _tree_set_index = new IntNodeMap(_graph); |
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139 | _tree_set = new TreeSet(*_tree_set_index); |
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140 | } |
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141 | _node_queue.resize(_node_num); |
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142 | } |
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143 | |
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144 | void destroyStructures() { |
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145 | if (_matching) { |
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146 | delete _matching; |
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147 | } |
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148 | if (_status) { |
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149 | delete _status; |
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150 | } |
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151 | if (_ear) { |
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152 | delete _ear; |
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153 | } |
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154 | if (_blossom_set) { |
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155 | delete _blossom_set; |
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156 | delete _blossom_set_index; |
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157 | } |
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158 | if (_blossom_rep) { |
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159 | delete _blossom_rep; |
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160 | } |
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161 | if (_tree_set) { |
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162 | delete _tree_set_index; |
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163 | delete _tree_set; |
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164 | } |
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165 | } |
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166 | |
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167 | void processDense(const Node& n) { |
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168 | _process = _postpone = _last = 0; |
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169 | _node_queue[_last++] = n; |
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170 | |
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171 | while (_process != _last) { |
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172 | Node u = _node_queue[_process++]; |
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173 | for (OutArcIt a(_graph, u); a != INVALID; ++a) { |
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174 | Node v = _graph.target(a); |
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175 | if ((*_status)[v] == MATCHED) { |
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176 | extendOnArc(a); |
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177 | } else if ((*_status)[v] == UNMATCHED) { |
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178 | augmentOnArc(a); |
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179 | return; |
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180 | } |
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181 | } |
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182 | } |
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183 | |
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184 | while (_postpone != _last) { |
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185 | Node u = _node_queue[_postpone++]; |
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186 | |
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187 | for (OutArcIt a(_graph, u); a != INVALID ; ++a) { |
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188 | Node v = _graph.target(a); |
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189 | |
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190 | if ((*_status)[v] == EVEN) { |
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191 | if (_blossom_set->find(u) != _blossom_set->find(v)) { |
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192 | shrinkOnEdge(a); |
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193 | } |
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194 | } |
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195 | |
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196 | while (_process != _last) { |
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197 | Node w = _node_queue[_process++]; |
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198 | for (OutArcIt b(_graph, w); b != INVALID; ++b) { |
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199 | Node x = _graph.target(b); |
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200 | if ((*_status)[x] == MATCHED) { |
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201 | extendOnArc(b); |
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202 | } else if ((*_status)[x] == UNMATCHED) { |
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203 | augmentOnArc(b); |
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204 | return; |
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205 | } |
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206 | } |
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207 | } |
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208 | } |
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209 | } |
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210 | } |
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211 | |
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212 | void processSparse(const Node& n) { |
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213 | _process = _last = 0; |
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214 | _node_queue[_last++] = n; |
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215 | while (_process != _last) { |
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216 | Node u = _node_queue[_process++]; |
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217 | for (OutArcIt a(_graph, u); a != INVALID; ++a) { |
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218 | Node v = _graph.target(a); |
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219 | |
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220 | if ((*_status)[v] == EVEN) { |
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221 | if (_blossom_set->find(u) != _blossom_set->find(v)) { |
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222 | shrinkOnEdge(a); |
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223 | } |
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224 | } else if ((*_status)[v] == MATCHED) { |
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225 | extendOnArc(a); |
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226 | } else if ((*_status)[v] == UNMATCHED) { |
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227 | augmentOnArc(a); |
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228 | return; |
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229 | } |
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230 | } |
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231 | } |
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232 | } |
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233 | |
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234 | void shrinkOnEdge(const Edge& e) { |
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235 | Node nca = INVALID; |
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236 | |
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237 | { |
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238 | std::set<Node> left_set, right_set; |
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239 | |
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240 | Node left = (*_blossom_rep)[_blossom_set->find(_graph.u(e))]; |
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241 | left_set.insert(left); |
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242 | |
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243 | Node right = (*_blossom_rep)[_blossom_set->find(_graph.v(e))]; |
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244 | right_set.insert(right); |
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245 | |
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246 | while (true) { |
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247 | if ((*_matching)[left] == INVALID) break; |
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248 | left = _graph.target((*_matching)[left]); |
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249 | left = (*_blossom_rep)[_blossom_set-> |
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250 | find(_graph.target((*_ear)[left]))]; |
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251 | if (right_set.find(left) != right_set.end()) { |
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252 | nca = left; |
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253 | break; |
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254 | } |
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255 | left_set.insert(left); |
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256 | |
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257 | if ((*_matching)[right] == INVALID) break; |
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258 | right = _graph.target((*_matching)[right]); |
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259 | right = (*_blossom_rep)[_blossom_set-> |
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260 | find(_graph.target((*_ear)[right]))]; |
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261 | if (left_set.find(right) != left_set.end()) { |
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262 | nca = right; |
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263 | break; |
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264 | } |
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265 | right_set.insert(right); |
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266 | } |
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267 | |
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268 | if (nca == INVALID) { |
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269 | if ((*_matching)[left] == INVALID) { |
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270 | nca = right; |
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271 | while (left_set.find(nca) == left_set.end()) { |
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272 | nca = _graph.target((*_matching)[nca]); |
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273 | nca =(*_blossom_rep)[_blossom_set-> |
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274 | find(_graph.target((*_ear)[nca]))]; |
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275 | } |
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276 | } else { |
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277 | nca = left; |
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278 | while (right_set.find(nca) == right_set.end()) { |
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279 | nca = _graph.target((*_matching)[nca]); |
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280 | nca = (*_blossom_rep)[_blossom_set-> |
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281 | find(_graph.target((*_ear)[nca]))]; |
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282 | } |
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283 | } |
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284 | } |
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285 | } |
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286 | |
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287 | { |
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288 | |
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289 | Node node = _graph.u(e); |
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290 | Arc arc = _graph.direct(e, true); |
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291 | Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
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292 | |
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293 | while (base != nca) { |
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294 | (*_ear)[node] = arc; |
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295 | |
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296 | Node n = node; |
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297 | while (n != base) { |
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298 | n = _graph.target((*_matching)[n]); |
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299 | Arc a = (*_ear)[n]; |
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300 | n = _graph.target(a); |
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301 | (*_ear)[n] = _graph.oppositeArc(a); |
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302 | } |
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303 | node = _graph.target((*_matching)[base]); |
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304 | _tree_set->erase(base); |
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305 | _tree_set->erase(node); |
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306 | _blossom_set->insert(node, _blossom_set->find(base)); |
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307 | (*_status)[node] = EVEN; |
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308 | _node_queue[_last++] = node; |
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309 | arc = _graph.oppositeArc((*_ear)[node]); |
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310 | node = _graph.target((*_ear)[node]); |
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311 | base = (*_blossom_rep)[_blossom_set->find(node)]; |
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312 | _blossom_set->join(_graph.target(arc), base); |
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313 | } |
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314 | } |
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315 | |
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316 | (*_blossom_rep)[_blossom_set->find(nca)] = nca; |
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317 | |
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318 | { |
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319 | |
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320 | Node node = _graph.v(e); |
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321 | Arc arc = _graph.direct(e, false); |
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322 | Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
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323 | |
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324 | while (base != nca) { |
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325 | (*_ear)[node] = arc; |
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326 | |
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327 | Node n = node; |
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328 | while (n != base) { |
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329 | n = _graph.target((*_matching)[n]); |
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330 | Arc a = (*_ear)[n]; |
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331 | n = _graph.target(a); |
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332 | (*_ear)[n] = _graph.oppositeArc(a); |
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333 | } |
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334 | node = _graph.target((*_matching)[base]); |
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335 | _tree_set->erase(base); |
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336 | _tree_set->erase(node); |
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337 | _blossom_set->insert(node, _blossom_set->find(base)); |
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338 | (*_status)[node] = EVEN; |
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339 | _node_queue[_last++] = node; |
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340 | arc = _graph.oppositeArc((*_ear)[node]); |
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341 | node = _graph.target((*_ear)[node]); |
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342 | base = (*_blossom_rep)[_blossom_set->find(node)]; |
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343 | _blossom_set->join(_graph.target(arc), base); |
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344 | } |
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345 | } |
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346 | |
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347 | (*_blossom_rep)[_blossom_set->find(nca)] = nca; |
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348 | } |
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349 | |
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350 | void extendOnArc(const Arc& a) { |
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351 | Node base = _graph.source(a); |
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352 | Node odd = _graph.target(a); |
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353 | |
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354 | (*_ear)[odd] = _graph.oppositeArc(a); |
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355 | Node even = _graph.target((*_matching)[odd]); |
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356 | (*_blossom_rep)[_blossom_set->insert(even)] = even; |
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357 | (*_status)[odd] = ODD; |
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358 | (*_status)[even] = EVEN; |
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359 | int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(base)]); |
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360 | _tree_set->insert(odd, tree); |
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361 | _tree_set->insert(even, tree); |
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362 | _node_queue[_last++] = even; |
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363 | |
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364 | } |
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365 | |
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366 | void augmentOnArc(const Arc& a) { |
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367 | Node even = _graph.source(a); |
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368 | Node odd = _graph.target(a); |
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369 | |
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370 | int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(even)]); |
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371 | |
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372 | (*_matching)[odd] = _graph.oppositeArc(a); |
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373 | (*_status)[odd] = MATCHED; |
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374 | |
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375 | Arc arc = (*_matching)[even]; |
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376 | (*_matching)[even] = a; |
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377 | |
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378 | while (arc != INVALID) { |
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379 | odd = _graph.target(arc); |
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380 | arc = (*_ear)[odd]; |
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381 | even = _graph.target(arc); |
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382 | (*_matching)[odd] = arc; |
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383 | arc = (*_matching)[even]; |
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384 | (*_matching)[even] = _graph.oppositeArc((*_matching)[odd]); |
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385 | } |
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386 | |
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387 | for (typename TreeSet::ItemIt it(*_tree_set, tree); |
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388 | it != INVALID; ++it) { |
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389 | if ((*_status)[it] == ODD) { |
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390 | (*_status)[it] = MATCHED; |
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391 | } else { |
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392 | int blossom = _blossom_set->find(it); |
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393 | for (typename BlossomSet::ItemIt jt(*_blossom_set, blossom); |
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394 | jt != INVALID; ++jt) { |
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395 | (*_status)[jt] = MATCHED; |
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396 | } |
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397 | _blossom_set->eraseClass(blossom); |
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398 | } |
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399 | } |
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400 | _tree_set->eraseClass(tree); |
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401 | |
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402 | } |
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403 | |
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404 | public: |
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405 | |
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406 | /// \brief Constructor |
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407 | /// |
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408 | /// Constructor. |
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409 | MaxMatching(const Graph& graph) |
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410 | : _graph(graph), _matching(0), _status(0), _ear(0), |
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411 | _blossom_set_index(0), _blossom_set(0), _blossom_rep(0), |
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412 | _tree_set_index(0), _tree_set(0) {} |
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413 | |
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414 | ~MaxMatching() { |
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415 | destroyStructures(); |
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416 | } |
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417 | |
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418 | /// \name Execution Control |
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419 | /// The simplest way to execute the algorithm is to use the |
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420 | /// \c run() member function.\n |
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421 | /// If you need better control on the execution, you have to call |
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422 | /// one of the functions \ref init(), \ref greedyInit() or |
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423 | /// \ref matchingInit() first, then you can start the algorithm with |
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424 | /// \ref startSparse() or \ref startDense(). |
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425 | |
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426 | ///@{ |
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427 | |
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428 | /// \brief Set the initial matching to the empty matching. |
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429 | /// |
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430 | /// This function sets the initial matching to the empty matching. |
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431 | void init() { |
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432 | createStructures(); |
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433 | for(NodeIt n(_graph); n != INVALID; ++n) { |
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434 | (*_matching)[n] = INVALID; |
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435 | (*_status)[n] = UNMATCHED; |
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436 | } |
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437 | } |
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438 | |
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439 | /// \brief Find an initial matching in a greedy way. |
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440 | /// |
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441 | /// This function finds an initial matching in a greedy way. |
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442 | void greedyInit() { |
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443 | createStructures(); |
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444 | for (NodeIt n(_graph); n != INVALID; ++n) { |
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445 | (*_matching)[n] = INVALID; |
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446 | (*_status)[n] = UNMATCHED; |
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447 | } |
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448 | for (NodeIt n(_graph); n != INVALID; ++n) { |
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449 | if ((*_matching)[n] == INVALID) { |
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450 | for (OutArcIt a(_graph, n); a != INVALID ; ++a) { |
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451 | Node v = _graph.target(a); |
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452 | if ((*_matching)[v] == INVALID && v != n) { |
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453 | (*_matching)[n] = a; |
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454 | (*_status)[n] = MATCHED; |
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455 | (*_matching)[v] = _graph.oppositeArc(a); |
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456 | (*_status)[v] = MATCHED; |
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457 | break; |
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458 | } |
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459 | } |
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460 | } |
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461 | } |
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462 | } |
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463 | |
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464 | |
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465 | /// \brief Initialize the matching from a map. |
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466 | /// |
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467 | /// This function initializes the matching from a \c bool valued edge |
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468 | /// map. This map should have the property that there are no two incident |
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469 | /// edges with \c true value, i.e. it really contains a matching. |
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470 | /// \return \c true if the map contains a matching. |
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471 | template <typename MatchingMap> |
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472 | bool matchingInit(const MatchingMap& matching) { |
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473 | createStructures(); |
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474 | |
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475 | for (NodeIt n(_graph); n != INVALID; ++n) { |
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476 | (*_matching)[n] = INVALID; |
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477 | (*_status)[n] = UNMATCHED; |
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478 | } |
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479 | for(EdgeIt e(_graph); e!=INVALID; ++e) { |
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480 | if (matching[e]) { |
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481 | |
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482 | Node u = _graph.u(e); |
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483 | if ((*_matching)[u] != INVALID) return false; |
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484 | (*_matching)[u] = _graph.direct(e, true); |
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485 | (*_status)[u] = MATCHED; |
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486 | |
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487 | Node v = _graph.v(e); |
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488 | if ((*_matching)[v] != INVALID) return false; |
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489 | (*_matching)[v] = _graph.direct(e, false); |
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490 | (*_status)[v] = MATCHED; |
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491 | } |
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492 | } |
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493 | return true; |
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494 | } |
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495 | |
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496 | /// \brief Start Edmonds' algorithm |
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497 | /// |
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498 | /// This function runs the original Edmonds' algorithm. |
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499 | /// |
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500 | /// \pre \ref Init(), \ref greedyInit() or \ref matchingInit() must be |
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501 | /// called before using this function. |
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502 | void startSparse() { |
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503 | for(NodeIt n(_graph); n != INVALID; ++n) { |
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504 | if ((*_status)[n] == UNMATCHED) { |
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505 | (*_blossom_rep)[_blossom_set->insert(n)] = n; |
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506 | _tree_set->insert(n); |
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507 | (*_status)[n] = EVEN; |
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508 | processSparse(n); |
---|
509 | } |
---|
510 | } |
---|
511 | } |
---|
512 | |
---|
513 | /// \brief Start Edmonds' algorithm with a heuristic improvement |
---|
514 | /// for dense graphs |
---|
515 | /// |
---|
516 | /// This function runs Edmonds' algorithm with a heuristic of postponing |
---|
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. |
---|
521 | void startDense() { |
---|
522 | for(NodeIt n(_graph); n != INVALID; ++n) { |
---|
523 | if ((*_status)[n] == UNMATCHED) { |
---|
524 | (*_blossom_rep)[_blossom_set->insert(n)] = n; |
---|
525 | _tree_set->insert(n); |
---|
526 | (*_status)[n] = EVEN; |
---|
527 | processDense(n); |
---|
528 | } |
---|
529 | } |
---|
530 | } |
---|
531 | |
---|
532 | |
---|
533 | /// \brief Run Edmonds' algorithm |
---|
534 | /// |
---|
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). |
---|
538 | void run() { |
---|
539 | if (countEdges(_graph) < 2 * countNodes(_graph)) { |
---|
540 | greedyInit(); |
---|
541 | startSparse(); |
---|
542 | } else { |
---|
543 | init(); |
---|
544 | startDense(); |
---|
545 | } |
---|
546 | } |
---|
547 | |
---|
548 | /// @} |
---|
549 | |
---|
550 | /// \name Primal Solution |
---|
551 | /// Functions to get the primal solution, i.e. the maximum matching. |
---|
552 | |
---|
553 | /// @{ |
---|
554 | |
---|
555 | /// \brief Return the size (cardinality) of the matching. |
---|
556 | /// |
---|
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. |
---|
559 | int matchingSize() const { |
---|
560 | int size = 0; |
---|
561 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
562 | if ((*_matching)[n] != INVALID) { |
---|
563 | ++size; |
---|
564 | } |
---|
565 | } |
---|
566 | return size / 2; |
---|
567 | } |
---|
568 | |
---|
569 | /// \brief Return \c true if the given edge is in the matching. |
---|
570 | /// |
---|
571 | /// This function returns \c true if the given edge is in the current |
---|
572 | /// matching. |
---|
573 | bool matching(const Edge& edge) const { |
---|
574 | return edge == (*_matching)[_graph.u(edge)]; |
---|
575 | } |
---|
576 | |
---|
577 | /// \brief Return the matching arc (or edge) incident to the given node. |
---|
578 | /// |
---|
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. |
---|
582 | Arc matching(const Node& n) const { |
---|
583 | return (*_matching)[n]; |
---|
584 | } |
---|
585 | |
---|
586 | /// \brief Return the mate of the given node. |
---|
587 | /// |
---|
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. |
---|
590 | Node mate(const Node& n) const { |
---|
591 | return (*_matching)[n] != INVALID ? |
---|
592 | _graph.target((*_matching)[n]) : INVALID; |
---|
593 | } |
---|
594 | |
---|
595 | /// @} |
---|
596 | |
---|
597 | /// \name Dual Solution |
---|
598 | /// Functions to get the dual solution, i.e. the Gallai-Edmonds |
---|
599 | /// decomposition. |
---|
600 | |
---|
601 | /// @{ |
---|
602 | |
---|
603 | /// \brief Return the status of the given node in the Edmonds-Gallai |
---|
604 | /// decomposition. |
---|
605 | /// |
---|
606 | /// This function returns the \ref Status "status" of the given node |
---|
607 | /// in the Edmonds-Gallai decomposition. |
---|
608 | Status decomposition(const Node& n) const { |
---|
609 | return (*_status)[n]; |
---|
610 | } |
---|
611 | |
---|
612 | /// \brief Return \c true if the given node is in the barrier. |
---|
613 | /// |
---|
614 | /// This function returns \c true if the given node is in the barrier. |
---|
615 | bool barrier(const Node& n) const { |
---|
616 | return (*_status)[n] == ODD; |
---|
617 | } |
---|
618 | |
---|
619 | /// @} |
---|
620 | |
---|
621 | }; |
---|
622 | |
---|
623 | /// \ingroup matching |
---|
624 | /// |
---|
625 | /// \brief Weighted matching in general graphs |
---|
626 | /// |
---|
627 | /// This class provides an efficient implementation of Edmond's |
---|
628 | /// maximum weighted matching algorithm. The implementation is based |
---|
629 | /// on extensive use of priority queues and provides |
---|
630 | /// \f$O(nm\log n)\f$ time complexity. |
---|
631 | /// |
---|
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. |
---|
636 | /// \f[ \sum_{e \in \delta(u)}x_e \le 1 \quad \forall u\in V\f] |
---|
637 | /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2} |
---|
638 | \quad \forall B\in\mathcal{O}\f] */ |
---|
639 | /// \f[x_e \ge 0\quad \forall e\in E\f] |
---|
640 | /// \f[\max \sum_{e\in E}x_ew_e\f] |
---|
641 | /// where \f$\delta(X)\f$ is the set of edges incident to a node in |
---|
642 | /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in |
---|
643 | /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality |
---|
644 | /// subsets of the nodes. |
---|
645 | /// |
---|
646 | /// The algorithm calculates an optimal matching and a proof of the |
---|
647 | /// optimality. The solution of the dual problem can be used to check |
---|
648 | /// the result of the algorithm. The dual linear problem is the |
---|
649 | /// following. |
---|
650 | /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)} |
---|
651 | z_B \ge w_{uv} \quad \forall uv\in E\f] */ |
---|
652 | /// \f[y_u \ge 0 \quad \forall u \in V\f] |
---|
653 | /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f] |
---|
654 | /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}} |
---|
655 | \frac{\vert B \vert - 1}{2}z_B\f] */ |
---|
656 | /// |
---|
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 |
---|
671 | template <typename GR, |
---|
672 | typename WM = typename GR::template EdgeMap<int> > |
---|
673 | #endif |
---|
674 | class MaxWeightedMatching { |
---|
675 | public: |
---|
676 | |
---|
677 | /// The graph type of the algorithm |
---|
678 | typedef GR Graph; |
---|
679 | /// The type of the edge weight map |
---|
680 | typedef WM WeightMap; |
---|
681 | /// The value type of the edge weights |
---|
682 | typedef typename WeightMap::Value Value; |
---|
683 | |
---|
684 | typedef typename Graph::template NodeMap<typename Graph::Arc> |
---|
685 | MatchingMap; |
---|
686 | |
---|
687 | /// \brief Scaling factor for dual solution |
---|
688 | /// |
---|
689 | /// Scaling factor for dual solution. It is equal to 4 or 1 |
---|
690 | /// according to the value type. |
---|
691 | static const int dualScale = |
---|
692 | std::numeric_limits<Value>::is_integer ? 4 : 1; |
---|
693 | |
---|
694 | private: |
---|
695 | |
---|
696 | TEMPLATE_GRAPH_TYPEDEFS(Graph); |
---|
697 | |
---|
698 | typedef typename Graph::template NodeMap<Value> NodePotential; |
---|
699 | typedef std::vector<Node> BlossomNodeList; |
---|
700 | |
---|
701 | struct BlossomVariable { |
---|
702 | int begin, end; |
---|
703 | Value value; |
---|
704 | |
---|
705 | BlossomVariable(int _begin, int _end, Value _value) |
---|
706 | : begin(_begin), end(_end), value(_value) {} |
---|
707 | |
---|
708 | }; |
---|
709 | |
---|
710 | typedef std::vector<BlossomVariable> BlossomPotential; |
---|
711 | |
---|
712 | const Graph& _graph; |
---|
713 | const WeightMap& _weight; |
---|
714 | |
---|
715 | MatchingMap* _matching; |
---|
716 | |
---|
717 | NodePotential* _node_potential; |
---|
718 | |
---|
719 | BlossomPotential _blossom_potential; |
---|
720 | BlossomNodeList _blossom_node_list; |
---|
721 | |
---|
722 | int _node_num; |
---|
723 | int _blossom_num; |
---|
724 | |
---|
725 | typedef RangeMap<int> IntIntMap; |
---|
726 | |
---|
727 | enum Status { |
---|
728 | EVEN = -1, MATCHED = 0, ODD = 1, UNMATCHED = -2 |
---|
729 | }; |
---|
730 | |
---|
731 | typedef HeapUnionFind<Value, IntNodeMap> BlossomSet; |
---|
732 | struct BlossomData { |
---|
733 | int tree; |
---|
734 | Status status; |
---|
735 | Arc pred, next; |
---|
736 | Value pot, offset; |
---|
737 | Node base; |
---|
738 | }; |
---|
739 | |
---|
740 | IntNodeMap *_blossom_index; |
---|
741 | BlossomSet *_blossom_set; |
---|
742 | RangeMap<BlossomData>* _blossom_data; |
---|
743 | |
---|
744 | IntNodeMap *_node_index; |
---|
745 | IntArcMap *_node_heap_index; |
---|
746 | |
---|
747 | struct NodeData { |
---|
748 | |
---|
749 | NodeData(IntArcMap& node_heap_index) |
---|
750 | : heap(node_heap_index) {} |
---|
751 | |
---|
752 | int blossom; |
---|
753 | Value pot; |
---|
754 | BinHeap<Value, IntArcMap> heap; |
---|
755 | std::map<int, Arc> heap_index; |
---|
756 | |
---|
757 | int tree; |
---|
758 | }; |
---|
759 | |
---|
760 | RangeMap<NodeData>* _node_data; |
---|
761 | |
---|
762 | typedef ExtendFindEnum<IntIntMap> TreeSet; |
---|
763 | |
---|
764 | IntIntMap *_tree_set_index; |
---|
765 | TreeSet *_tree_set; |
---|
766 | |
---|
767 | IntNodeMap *_delta1_index; |
---|
768 | BinHeap<Value, IntNodeMap> *_delta1; |
---|
769 | |
---|
770 | IntIntMap *_delta2_index; |
---|
771 | BinHeap<Value, IntIntMap> *_delta2; |
---|
772 | |
---|
773 | IntEdgeMap *_delta3_index; |
---|
774 | BinHeap<Value, IntEdgeMap> *_delta3; |
---|
775 | |
---|
776 | IntIntMap *_delta4_index; |
---|
777 | BinHeap<Value, IntIntMap> *_delta4; |
---|
778 | |
---|
779 | Value _delta_sum; |
---|
780 | |
---|
781 | void createStructures() { |
---|
782 | _node_num = countNodes(_graph); |
---|
783 | _blossom_num = _node_num * 3 / 2; |
---|
784 | |
---|
785 | if (!_matching) { |
---|
786 | _matching = new MatchingMap(_graph); |
---|
787 | } |
---|
788 | if (!_node_potential) { |
---|
789 | _node_potential = new NodePotential(_graph); |
---|
790 | } |
---|
791 | if (!_blossom_set) { |
---|
792 | _blossom_index = new IntNodeMap(_graph); |
---|
793 | _blossom_set = new BlossomSet(*_blossom_index); |
---|
794 | _blossom_data = new RangeMap<BlossomData>(_blossom_num); |
---|
795 | } |
---|
796 | |
---|
797 | if (!_node_index) { |
---|
798 | _node_index = new IntNodeMap(_graph); |
---|
799 | _node_heap_index = new IntArcMap(_graph); |
---|
800 | _node_data = new RangeMap<NodeData>(_node_num, |
---|
801 | NodeData(*_node_heap_index)); |
---|
802 | } |
---|
803 | |
---|
804 | if (!_tree_set) { |
---|
805 | _tree_set_index = new IntIntMap(_blossom_num); |
---|
806 | _tree_set = new TreeSet(*_tree_set_index); |
---|
807 | } |
---|
808 | if (!_delta1) { |
---|
809 | _delta1_index = new IntNodeMap(_graph); |
---|
810 | _delta1 = new BinHeap<Value, IntNodeMap>(*_delta1_index); |
---|
811 | } |
---|
812 | if (!_delta2) { |
---|
813 | _delta2_index = new IntIntMap(_blossom_num); |
---|
814 | _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index); |
---|
815 | } |
---|
816 | if (!_delta3) { |
---|
817 | _delta3_index = new IntEdgeMap(_graph); |
---|
818 | _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index); |
---|
819 | } |
---|
820 | if (!_delta4) { |
---|
821 | _delta4_index = new IntIntMap(_blossom_num); |
---|
822 | _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index); |
---|
823 | } |
---|
824 | } |
---|
825 | |
---|
826 | void destroyStructures() { |
---|
827 | _node_num = countNodes(_graph); |
---|
828 | _blossom_num = _node_num * 3 / 2; |
---|
829 | |
---|
830 | if (_matching) { |
---|
831 | delete _matching; |
---|
832 | } |
---|
833 | if (_node_potential) { |
---|
834 | delete _node_potential; |
---|
835 | } |
---|
836 | if (_blossom_set) { |
---|
837 | delete _blossom_index; |
---|
838 | delete _blossom_set; |
---|
839 | delete _blossom_data; |
---|
840 | } |
---|
841 | |
---|
842 | if (_node_index) { |
---|
843 | delete _node_index; |
---|
844 | delete _node_heap_index; |
---|
845 | delete _node_data; |
---|
846 | } |
---|
847 | |
---|
848 | if (_tree_set) { |
---|
849 | delete _tree_set_index; |
---|
850 | delete _tree_set; |
---|
851 | } |
---|
852 | if (_delta1) { |
---|
853 | delete _delta1_index; |
---|
854 | delete _delta1; |
---|
855 | } |
---|
856 | if (_delta2) { |
---|
857 | delete _delta2_index; |
---|
858 | delete _delta2; |
---|
859 | } |
---|
860 | if (_delta3) { |
---|
861 | delete _delta3_index; |
---|
862 | delete _delta3; |
---|
863 | } |
---|
864 | if (_delta4) { |
---|
865 | delete _delta4_index; |
---|
866 | delete _delta4; |
---|
867 | } |
---|
868 | } |
---|
869 | |
---|
870 | void matchedToEven(int blossom, int tree) { |
---|
871 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
872 | _delta2->erase(blossom); |
---|
873 | } |
---|
874 | |
---|
875 | if (!_blossom_set->trivial(blossom)) { |
---|
876 | (*_blossom_data)[blossom].pot -= |
---|
877 | 2 * (_delta_sum - (*_blossom_data)[blossom].offset); |
---|
878 | } |
---|
879 | |
---|
880 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
881 | n != INVALID; ++n) { |
---|
882 | |
---|
883 | _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
---|
884 | int ni = (*_node_index)[n]; |
---|
885 | |
---|
886 | (*_node_data)[ni].heap.clear(); |
---|
887 | (*_node_data)[ni].heap_index.clear(); |
---|
888 | |
---|
889 | (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset; |
---|
890 | |
---|
891 | _delta1->push(n, (*_node_data)[ni].pot); |
---|
892 | |
---|
893 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
894 | Node v = _graph.source(e); |
---|
895 | int vb = _blossom_set->find(v); |
---|
896 | int vi = (*_node_index)[v]; |
---|
897 | |
---|
898 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
899 | dualScale * _weight[e]; |
---|
900 | |
---|
901 | if ((*_blossom_data)[vb].status == EVEN) { |
---|
902 | if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
---|
903 | _delta3->push(e, rw / 2); |
---|
904 | } |
---|
905 | } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
---|
906 | if (_delta3->state(e) != _delta3->IN_HEAP) { |
---|
907 | _delta3->push(e, rw); |
---|
908 | } |
---|
909 | } else { |
---|
910 | typename std::map<int, Arc>::iterator it = |
---|
911 | (*_node_data)[vi].heap_index.find(tree); |
---|
912 | |
---|
913 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
914 | if ((*_node_data)[vi].heap[it->second] > rw) { |
---|
915 | (*_node_data)[vi].heap.replace(it->second, e); |
---|
916 | (*_node_data)[vi].heap.decrease(e, rw); |
---|
917 | it->second = e; |
---|
918 | } |
---|
919 | } else { |
---|
920 | (*_node_data)[vi].heap.push(e, rw); |
---|
921 | (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
---|
922 | } |
---|
923 | |
---|
924 | if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
---|
925 | _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
---|
926 | |
---|
927 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
928 | if (_delta2->state(vb) != _delta2->IN_HEAP) { |
---|
929 | _delta2->push(vb, _blossom_set->classPrio(vb) - |
---|
930 | (*_blossom_data)[vb].offset); |
---|
931 | } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
---|
932 | (*_blossom_data)[vb].offset){ |
---|
933 | _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
---|
934 | (*_blossom_data)[vb].offset); |
---|
935 | } |
---|
936 | } |
---|
937 | } |
---|
938 | } |
---|
939 | } |
---|
940 | } |
---|
941 | (*_blossom_data)[blossom].offset = 0; |
---|
942 | } |
---|
943 | |
---|
944 | void matchedToOdd(int blossom) { |
---|
945 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
946 | _delta2->erase(blossom); |
---|
947 | } |
---|
948 | (*_blossom_data)[blossom].offset += _delta_sum; |
---|
949 | if (!_blossom_set->trivial(blossom)) { |
---|
950 | _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 + |
---|
951 | (*_blossom_data)[blossom].offset); |
---|
952 | } |
---|
953 | } |
---|
954 | |
---|
955 | void evenToMatched(int blossom, int tree) { |
---|
956 | if (!_blossom_set->trivial(blossom)) { |
---|
957 | (*_blossom_data)[blossom].pot += 2 * _delta_sum; |
---|
958 | } |
---|
959 | |
---|
960 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
961 | n != INVALID; ++n) { |
---|
962 | int ni = (*_node_index)[n]; |
---|
963 | (*_node_data)[ni].pot -= _delta_sum; |
---|
964 | |
---|
965 | _delta1->erase(n); |
---|
966 | |
---|
967 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
968 | Node v = _graph.source(e); |
---|
969 | int vb = _blossom_set->find(v); |
---|
970 | int vi = (*_node_index)[v]; |
---|
971 | |
---|
972 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
973 | dualScale * _weight[e]; |
---|
974 | |
---|
975 | if (vb == blossom) { |
---|
976 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
977 | _delta3->erase(e); |
---|
978 | } |
---|
979 | } else if ((*_blossom_data)[vb].status == EVEN) { |
---|
980 | |
---|
981 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
982 | _delta3->erase(e); |
---|
983 | } |
---|
984 | |
---|
985 | int vt = _tree_set->find(vb); |
---|
986 | |
---|
987 | if (vt != tree) { |
---|
988 | |
---|
989 | Arc r = _graph.oppositeArc(e); |
---|
990 | |
---|
991 | typename std::map<int, Arc>::iterator it = |
---|
992 | (*_node_data)[ni].heap_index.find(vt); |
---|
993 | |
---|
994 | if (it != (*_node_data)[ni].heap_index.end()) { |
---|
995 | if ((*_node_data)[ni].heap[it->second] > rw) { |
---|
996 | (*_node_data)[ni].heap.replace(it->second, r); |
---|
997 | (*_node_data)[ni].heap.decrease(r, rw); |
---|
998 | it->second = r; |
---|
999 | } |
---|
1000 | } else { |
---|
1001 | (*_node_data)[ni].heap.push(r, rw); |
---|
1002 | (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
---|
1003 | } |
---|
1004 | |
---|
1005 | if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
---|
1006 | _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
---|
1007 | |
---|
1008 | if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
---|
1009 | _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
---|
1010 | (*_blossom_data)[blossom].offset); |
---|
1011 | } else if ((*_delta2)[blossom] > |
---|
1012 | _blossom_set->classPrio(blossom) - |
---|
1013 | (*_blossom_data)[blossom].offset){ |
---|
1014 | _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
---|
1015 | (*_blossom_data)[blossom].offset); |
---|
1016 | } |
---|
1017 | } |
---|
1018 | } |
---|
1019 | |
---|
1020 | } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
---|
1021 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
1022 | _delta3->erase(e); |
---|
1023 | } |
---|
1024 | } else { |
---|
1025 | |
---|
1026 | typename std::map<int, Arc>::iterator it = |
---|
1027 | (*_node_data)[vi].heap_index.find(tree); |
---|
1028 | |
---|
1029 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
1030 | (*_node_data)[vi].heap.erase(it->second); |
---|
1031 | (*_node_data)[vi].heap_index.erase(it); |
---|
1032 | if ((*_node_data)[vi].heap.empty()) { |
---|
1033 | _blossom_set->increase(v, std::numeric_limits<Value>::max()); |
---|
1034 | } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) { |
---|
1035 | _blossom_set->increase(v, (*_node_data)[vi].heap.prio()); |
---|
1036 | } |
---|
1037 | |
---|
1038 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
1039 | if (_blossom_set->classPrio(vb) == |
---|
1040 | std::numeric_limits<Value>::max()) { |
---|
1041 | _delta2->erase(vb); |
---|
1042 | } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) - |
---|
1043 | (*_blossom_data)[vb].offset) { |
---|
1044 | _delta2->increase(vb, _blossom_set->classPrio(vb) - |
---|
1045 | (*_blossom_data)[vb].offset); |
---|
1046 | } |
---|
1047 | } |
---|
1048 | } |
---|
1049 | } |
---|
1050 | } |
---|
1051 | } |
---|
1052 | } |
---|
1053 | |
---|
1054 | void oddToMatched(int blossom) { |
---|
1055 | (*_blossom_data)[blossom].offset -= _delta_sum; |
---|
1056 | |
---|
1057 | if (_blossom_set->classPrio(blossom) != |
---|
1058 | std::numeric_limits<Value>::max()) { |
---|
1059 | _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
---|
1060 | (*_blossom_data)[blossom].offset); |
---|
1061 | } |
---|
1062 | |
---|
1063 | if (!_blossom_set->trivial(blossom)) { |
---|
1064 | _delta4->erase(blossom); |
---|
1065 | } |
---|
1066 | } |
---|
1067 | |
---|
1068 | void oddToEven(int blossom, int tree) { |
---|
1069 | if (!_blossom_set->trivial(blossom)) { |
---|
1070 | _delta4->erase(blossom); |
---|
1071 | (*_blossom_data)[blossom].pot -= |
---|
1072 | 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset); |
---|
1073 | } |
---|
1074 | |
---|
1075 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
1076 | n != INVALID; ++n) { |
---|
1077 | int ni = (*_node_index)[n]; |
---|
1078 | |
---|
1079 | _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
---|
1080 | |
---|
1081 | (*_node_data)[ni].heap.clear(); |
---|
1082 | (*_node_data)[ni].heap_index.clear(); |
---|
1083 | (*_node_data)[ni].pot += |
---|
1084 | 2 * _delta_sum - (*_blossom_data)[blossom].offset; |
---|
1085 | |
---|
1086 | _delta1->push(n, (*_node_data)[ni].pot); |
---|
1087 | |
---|
1088 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
1089 | Node v = _graph.source(e); |
---|
1090 | int vb = _blossom_set->find(v); |
---|
1091 | int vi = (*_node_index)[v]; |
---|
1092 | |
---|
1093 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
1094 | dualScale * _weight[e]; |
---|
1095 | |
---|
1096 | if ((*_blossom_data)[vb].status == EVEN) { |
---|
1097 | if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
---|
1098 | _delta3->push(e, rw / 2); |
---|
1099 | } |
---|
1100 | } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
---|
1101 | if (_delta3->state(e) != _delta3->IN_HEAP) { |
---|
1102 | _delta3->push(e, rw); |
---|
1103 | } |
---|
1104 | } else { |
---|
1105 | |
---|
1106 | typename std::map<int, Arc>::iterator it = |
---|
1107 | (*_node_data)[vi].heap_index.find(tree); |
---|
1108 | |
---|
1109 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
1110 | if ((*_node_data)[vi].heap[it->second] > rw) { |
---|
1111 | (*_node_data)[vi].heap.replace(it->second, e); |
---|
1112 | (*_node_data)[vi].heap.decrease(e, rw); |
---|
1113 | it->second = e; |
---|
1114 | } |
---|
1115 | } else { |
---|
1116 | (*_node_data)[vi].heap.push(e, rw); |
---|
1117 | (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
---|
1118 | } |
---|
1119 | |
---|
1120 | if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
---|
1121 | _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
---|
1122 | |
---|
1123 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
1124 | if (_delta2->state(vb) != _delta2->IN_HEAP) { |
---|
1125 | _delta2->push(vb, _blossom_set->classPrio(vb) - |
---|
1126 | (*_blossom_data)[vb].offset); |
---|
1127 | } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
---|
1128 | (*_blossom_data)[vb].offset) { |
---|
1129 | _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
---|
1130 | (*_blossom_data)[vb].offset); |
---|
1131 | } |
---|
1132 | } |
---|
1133 | } |
---|
1134 | } |
---|
1135 | } |
---|
1136 | } |
---|
1137 | (*_blossom_data)[blossom].offset = 0; |
---|
1138 | } |
---|
1139 | |
---|
1140 | |
---|
1141 | void matchedToUnmatched(int blossom) { |
---|
1142 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
1143 | _delta2->erase(blossom); |
---|
1144 | } |
---|
1145 | |
---|
1146 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
1147 | n != INVALID; ++n) { |
---|
1148 | int ni = (*_node_index)[n]; |
---|
1149 | |
---|
1150 | _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
---|
1151 | |
---|
1152 | (*_node_data)[ni].heap.clear(); |
---|
1153 | (*_node_data)[ni].heap_index.clear(); |
---|
1154 | |
---|
1155 | for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
---|
1156 | Node v = _graph.target(e); |
---|
1157 | int vb = _blossom_set->find(v); |
---|
1158 | int vi = (*_node_index)[v]; |
---|
1159 | |
---|
1160 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
1161 | dualScale * _weight[e]; |
---|
1162 | |
---|
1163 | if ((*_blossom_data)[vb].status == EVEN) { |
---|
1164 | if (_delta3->state(e) != _delta3->IN_HEAP) { |
---|
1165 | _delta3->push(e, rw); |
---|
1166 | } |
---|
1167 | } |
---|
1168 | } |
---|
1169 | } |
---|
1170 | } |
---|
1171 | |
---|
1172 | void unmatchedToMatched(int blossom) { |
---|
1173 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
1174 | n != INVALID; ++n) { |
---|
1175 | int ni = (*_node_index)[n]; |
---|
1176 | |
---|
1177 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
1178 | Node v = _graph.source(e); |
---|
1179 | int vb = _blossom_set->find(v); |
---|
1180 | int vi = (*_node_index)[v]; |
---|
1181 | |
---|
1182 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
1183 | dualScale * _weight[e]; |
---|
1184 | |
---|
1185 | if (vb == blossom) { |
---|
1186 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
1187 | _delta3->erase(e); |
---|
1188 | } |
---|
1189 | } else if ((*_blossom_data)[vb].status == EVEN) { |
---|
1190 | |
---|
1191 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
1192 | _delta3->erase(e); |
---|
1193 | } |
---|
1194 | |
---|
1195 | int vt = _tree_set->find(vb); |
---|
1196 | |
---|
1197 | Arc r = _graph.oppositeArc(e); |
---|
1198 | |
---|
1199 | typename std::map<int, Arc>::iterator it = |
---|
1200 | (*_node_data)[ni].heap_index.find(vt); |
---|
1201 | |
---|
1202 | if (it != (*_node_data)[ni].heap_index.end()) { |
---|
1203 | if ((*_node_data)[ni].heap[it->second] > rw) { |
---|
1204 | (*_node_data)[ni].heap.replace(it->second, r); |
---|
1205 | (*_node_data)[ni].heap.decrease(r, rw); |
---|
1206 | it->second = r; |
---|
1207 | } |
---|
1208 | } else { |
---|
1209 | (*_node_data)[ni].heap.push(r, rw); |
---|
1210 | (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
---|
1211 | } |
---|
1212 | |
---|
1213 | if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
---|
1214 | _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
---|
1215 | |
---|
1216 | if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
---|
1217 | _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
---|
1218 | (*_blossom_data)[blossom].offset); |
---|
1219 | } else if ((*_delta2)[blossom] > _blossom_set->classPrio(blossom)- |
---|
1220 | (*_blossom_data)[blossom].offset){ |
---|
1221 | _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
---|
1222 | (*_blossom_data)[blossom].offset); |
---|
1223 | } |
---|
1224 | } |
---|
1225 | |
---|
1226 | } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
---|
1227 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
1228 | _delta3->erase(e); |
---|
1229 | } |
---|
1230 | } |
---|
1231 | } |
---|
1232 | } |
---|
1233 | } |
---|
1234 | |
---|
1235 | void alternatePath(int even, int tree) { |
---|
1236 | int odd; |
---|
1237 | |
---|
1238 | evenToMatched(even, tree); |
---|
1239 | (*_blossom_data)[even].status = MATCHED; |
---|
1240 | |
---|
1241 | while ((*_blossom_data)[even].pred != INVALID) { |
---|
1242 | odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred)); |
---|
1243 | (*_blossom_data)[odd].status = MATCHED; |
---|
1244 | oddToMatched(odd); |
---|
1245 | (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred; |
---|
1246 | |
---|
1247 | even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred)); |
---|
1248 | (*_blossom_data)[even].status = MATCHED; |
---|
1249 | evenToMatched(even, tree); |
---|
1250 | (*_blossom_data)[even].next = |
---|
1251 | _graph.oppositeArc((*_blossom_data)[odd].pred); |
---|
1252 | } |
---|
1253 | |
---|
1254 | } |
---|
1255 | |
---|
1256 | void destroyTree(int tree) { |
---|
1257 | for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) { |
---|
1258 | if ((*_blossom_data)[b].status == EVEN) { |
---|
1259 | (*_blossom_data)[b].status = MATCHED; |
---|
1260 | evenToMatched(b, tree); |
---|
1261 | } else if ((*_blossom_data)[b].status == ODD) { |
---|
1262 | (*_blossom_data)[b].status = MATCHED; |
---|
1263 | oddToMatched(b); |
---|
1264 | } |
---|
1265 | } |
---|
1266 | _tree_set->eraseClass(tree); |
---|
1267 | } |
---|
1268 | |
---|
1269 | |
---|
1270 | void unmatchNode(const Node& node) { |
---|
1271 | int blossom = _blossom_set->find(node); |
---|
1272 | int tree = _tree_set->find(blossom); |
---|
1273 | |
---|
1274 | alternatePath(blossom, tree); |
---|
1275 | destroyTree(tree); |
---|
1276 | |
---|
1277 | (*_blossom_data)[blossom].status = UNMATCHED; |
---|
1278 | (*_blossom_data)[blossom].base = node; |
---|
1279 | matchedToUnmatched(blossom); |
---|
1280 | } |
---|
1281 | |
---|
1282 | |
---|
1283 | void augmentOnEdge(const Edge& edge) { |
---|
1284 | |
---|
1285 | int left = _blossom_set->find(_graph.u(edge)); |
---|
1286 | int right = _blossom_set->find(_graph.v(edge)); |
---|
1287 | |
---|
1288 | if ((*_blossom_data)[left].status == EVEN) { |
---|
1289 | int left_tree = _tree_set->find(left); |
---|
1290 | alternatePath(left, left_tree); |
---|
1291 | destroyTree(left_tree); |
---|
1292 | } else { |
---|
1293 | (*_blossom_data)[left].status = MATCHED; |
---|
1294 | unmatchedToMatched(left); |
---|
1295 | } |
---|
1296 | |
---|
1297 | if ((*_blossom_data)[right].status == EVEN) { |
---|
1298 | int right_tree = _tree_set->find(right); |
---|
1299 | alternatePath(right, right_tree); |
---|
1300 | destroyTree(right_tree); |
---|
1301 | } else { |
---|
1302 | (*_blossom_data)[right].status = MATCHED; |
---|
1303 | unmatchedToMatched(right); |
---|
1304 | } |
---|
1305 | |
---|
1306 | (*_blossom_data)[left].next = _graph.direct(edge, true); |
---|
1307 | (*_blossom_data)[right].next = _graph.direct(edge, false); |
---|
1308 | } |
---|
1309 | |
---|
1310 | void extendOnArc(const Arc& arc) { |
---|
1311 | int base = _blossom_set->find(_graph.target(arc)); |
---|
1312 | int tree = _tree_set->find(base); |
---|
1313 | |
---|
1314 | int odd = _blossom_set->find(_graph.source(arc)); |
---|
1315 | _tree_set->insert(odd, tree); |
---|
1316 | (*_blossom_data)[odd].status = ODD; |
---|
1317 | matchedToOdd(odd); |
---|
1318 | (*_blossom_data)[odd].pred = arc; |
---|
1319 | |
---|
1320 | int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next)); |
---|
1321 | (*_blossom_data)[even].pred = (*_blossom_data)[even].next; |
---|
1322 | _tree_set->insert(even, tree); |
---|
1323 | (*_blossom_data)[even].status = EVEN; |
---|
1324 | matchedToEven(even, tree); |
---|
1325 | } |
---|
1326 | |
---|
1327 | void shrinkOnEdge(const Edge& edge, int tree) { |
---|
1328 | int nca = -1; |
---|
1329 | std::vector<int> left_path, right_path; |
---|
1330 | |
---|
1331 | { |
---|
1332 | std::set<int> left_set, right_set; |
---|
1333 | int left = _blossom_set->find(_graph.u(edge)); |
---|
1334 | left_path.push_back(left); |
---|
1335 | left_set.insert(left); |
---|
1336 | |
---|
1337 | int right = _blossom_set->find(_graph.v(edge)); |
---|
1338 | right_path.push_back(right); |
---|
1339 | right_set.insert(right); |
---|
1340 | |
---|
1341 | while (true) { |
---|
1342 | |
---|
1343 | if ((*_blossom_data)[left].pred == INVALID) break; |
---|
1344 | |
---|
1345 | left = |
---|
1346 | _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
---|
1347 | left_path.push_back(left); |
---|
1348 | left = |
---|
1349 | _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
---|
1350 | left_path.push_back(left); |
---|
1351 | |
---|
1352 | left_set.insert(left); |
---|
1353 | |
---|
1354 | if (right_set.find(left) != right_set.end()) { |
---|
1355 | nca = left; |
---|
1356 | break; |
---|
1357 | } |
---|
1358 | |
---|
1359 | if ((*_blossom_data)[right].pred == INVALID) break; |
---|
1360 | |
---|
1361 | right = |
---|
1362 | _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
---|
1363 | right_path.push_back(right); |
---|
1364 | right = |
---|
1365 | _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
---|
1366 | right_path.push_back(right); |
---|
1367 | |
---|
1368 | right_set.insert(right); |
---|
1369 | |
---|
1370 | if (left_set.find(right) != left_set.end()) { |
---|
1371 | nca = right; |
---|
1372 | break; |
---|
1373 | } |
---|
1374 | |
---|
1375 | } |
---|
1376 | |
---|
1377 | if (nca == -1) { |
---|
1378 | if ((*_blossom_data)[left].pred == INVALID) { |
---|
1379 | nca = right; |
---|
1380 | while (left_set.find(nca) == left_set.end()) { |
---|
1381 | nca = |
---|
1382 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
1383 | right_path.push_back(nca); |
---|
1384 | nca = |
---|
1385 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
1386 | right_path.push_back(nca); |
---|
1387 | } |
---|
1388 | } else { |
---|
1389 | nca = left; |
---|
1390 | while (right_set.find(nca) == right_set.end()) { |
---|
1391 | nca = |
---|
1392 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
1393 | left_path.push_back(nca); |
---|
1394 | nca = |
---|
1395 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
1396 | left_path.push_back(nca); |
---|
1397 | } |
---|
1398 | } |
---|
1399 | } |
---|
1400 | } |
---|
1401 | |
---|
1402 | std::vector<int> subblossoms; |
---|
1403 | Arc prev; |
---|
1404 | |
---|
1405 | prev = _graph.direct(edge, true); |
---|
1406 | for (int i = 0; left_path[i] != nca; i += 2) { |
---|
1407 | subblossoms.push_back(left_path[i]); |
---|
1408 | (*_blossom_data)[left_path[i]].next = prev; |
---|
1409 | _tree_set->erase(left_path[i]); |
---|
1410 | |
---|
1411 | subblossoms.push_back(left_path[i + 1]); |
---|
1412 | (*_blossom_data)[left_path[i + 1]].status = EVEN; |
---|
1413 | oddToEven(left_path[i + 1], tree); |
---|
1414 | _tree_set->erase(left_path[i + 1]); |
---|
1415 | prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred); |
---|
1416 | } |
---|
1417 | |
---|
1418 | int k = 0; |
---|
1419 | while (right_path[k] != nca) ++k; |
---|
1420 | |
---|
1421 | subblossoms.push_back(nca); |
---|
1422 | (*_blossom_data)[nca].next = prev; |
---|
1423 | |
---|
1424 | for (int i = k - 2; i >= 0; i -= 2) { |
---|
1425 | subblossoms.push_back(right_path[i + 1]); |
---|
1426 | (*_blossom_data)[right_path[i + 1]].status = EVEN; |
---|
1427 | oddToEven(right_path[i + 1], tree); |
---|
1428 | _tree_set->erase(right_path[i + 1]); |
---|
1429 | |
---|
1430 | (*_blossom_data)[right_path[i + 1]].next = |
---|
1431 | (*_blossom_data)[right_path[i + 1]].pred; |
---|
1432 | |
---|
1433 | subblossoms.push_back(right_path[i]); |
---|
1434 | _tree_set->erase(right_path[i]); |
---|
1435 | } |
---|
1436 | |
---|
1437 | int surface = |
---|
1438 | _blossom_set->join(subblossoms.begin(), subblossoms.end()); |
---|
1439 | |
---|
1440 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
1441 | if (!_blossom_set->trivial(subblossoms[i])) { |
---|
1442 | (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum; |
---|
1443 | } |
---|
1444 | (*_blossom_data)[subblossoms[i]].status = MATCHED; |
---|
1445 | } |
---|
1446 | |
---|
1447 | (*_blossom_data)[surface].pot = -2 * _delta_sum; |
---|
1448 | (*_blossom_data)[surface].offset = 0; |
---|
1449 | (*_blossom_data)[surface].status = EVEN; |
---|
1450 | (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred; |
---|
1451 | (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred; |
---|
1452 | |
---|
1453 | _tree_set->insert(surface, tree); |
---|
1454 | _tree_set->erase(nca); |
---|
1455 | } |
---|
1456 | |
---|
1457 | void splitBlossom(int blossom) { |
---|
1458 | Arc next = (*_blossom_data)[blossom].next; |
---|
1459 | Arc pred = (*_blossom_data)[blossom].pred; |
---|
1460 | |
---|
1461 | int tree = _tree_set->find(blossom); |
---|
1462 | |
---|
1463 | (*_blossom_data)[blossom].status = MATCHED; |
---|
1464 | oddToMatched(blossom); |
---|
1465 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
1466 | _delta2->erase(blossom); |
---|
1467 | } |
---|
1468 | |
---|
1469 | std::vector<int> subblossoms; |
---|
1470 | _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
---|
1471 | |
---|
1472 | Value offset = (*_blossom_data)[blossom].offset; |
---|
1473 | int b = _blossom_set->find(_graph.source(pred)); |
---|
1474 | int d = _blossom_set->find(_graph.source(next)); |
---|
1475 | |
---|
1476 | int ib = -1, id = -1; |
---|
1477 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
1478 | if (subblossoms[i] == b) ib = i; |
---|
1479 | if (subblossoms[i] == d) id = i; |
---|
1480 | |
---|
1481 | (*_blossom_data)[subblossoms[i]].offset = offset; |
---|
1482 | if (!_blossom_set->trivial(subblossoms[i])) { |
---|
1483 | (*_blossom_data)[subblossoms[i]].pot -= 2 * offset; |
---|
1484 | } |
---|
1485 | if (_blossom_set->classPrio(subblossoms[i]) != |
---|
1486 | std::numeric_limits<Value>::max()) { |
---|
1487 | _delta2->push(subblossoms[i], |
---|
1488 | _blossom_set->classPrio(subblossoms[i]) - |
---|
1489 | (*_blossom_data)[subblossoms[i]].offset); |
---|
1490 | } |
---|
1491 | } |
---|
1492 | |
---|
1493 | if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) { |
---|
1494 | for (int i = (id + 1) % subblossoms.size(); |
---|
1495 | i != ib; i = (i + 2) % subblossoms.size()) { |
---|
1496 | int sb = subblossoms[i]; |
---|
1497 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
1498 | (*_blossom_data)[sb].next = |
---|
1499 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
1500 | } |
---|
1501 | |
---|
1502 | for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) { |
---|
1503 | int sb = subblossoms[i]; |
---|
1504 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
1505 | int ub = subblossoms[(i + 2) % subblossoms.size()]; |
---|
1506 | |
---|
1507 | (*_blossom_data)[sb].status = ODD; |
---|
1508 | matchedToOdd(sb); |
---|
1509 | _tree_set->insert(sb, tree); |
---|
1510 | (*_blossom_data)[sb].pred = pred; |
---|
1511 | (*_blossom_data)[sb].next = |
---|
1512 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
1513 | |
---|
1514 | pred = (*_blossom_data)[ub].next; |
---|
1515 | |
---|
1516 | (*_blossom_data)[tb].status = EVEN; |
---|
1517 | matchedToEven(tb, tree); |
---|
1518 | _tree_set->insert(tb, tree); |
---|
1519 | (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next; |
---|
1520 | } |
---|
1521 | |
---|
1522 | (*_blossom_data)[subblossoms[id]].status = ODD; |
---|
1523 | matchedToOdd(subblossoms[id]); |
---|
1524 | _tree_set->insert(subblossoms[id], tree); |
---|
1525 | (*_blossom_data)[subblossoms[id]].next = next; |
---|
1526 | (*_blossom_data)[subblossoms[id]].pred = pred; |
---|
1527 | |
---|
1528 | } else { |
---|
1529 | |
---|
1530 | for (int i = (ib + 1) % subblossoms.size(); |
---|
1531 | i != id; i = (i + 2) % subblossoms.size()) { |
---|
1532 | int sb = subblossoms[i]; |
---|
1533 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
1534 | (*_blossom_data)[sb].next = |
---|
1535 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
1536 | } |
---|
1537 | |
---|
1538 | for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) { |
---|
1539 | int sb = subblossoms[i]; |
---|
1540 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
1541 | int ub = subblossoms[(i + 2) % subblossoms.size()]; |
---|
1542 | |
---|
1543 | (*_blossom_data)[sb].status = ODD; |
---|
1544 | matchedToOdd(sb); |
---|
1545 | _tree_set->insert(sb, tree); |
---|
1546 | (*_blossom_data)[sb].next = next; |
---|
1547 | (*_blossom_data)[sb].pred = |
---|
1548 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
1549 | |
---|
1550 | (*_blossom_data)[tb].status = EVEN; |
---|
1551 | matchedToEven(tb, tree); |
---|
1552 | _tree_set->insert(tb, tree); |
---|
1553 | (*_blossom_data)[tb].pred = |
---|
1554 | (*_blossom_data)[tb].next = |
---|
1555 | _graph.oppositeArc((*_blossom_data)[ub].next); |
---|
1556 | next = (*_blossom_data)[ub].next; |
---|
1557 | } |
---|
1558 | |
---|
1559 | (*_blossom_data)[subblossoms[ib]].status = ODD; |
---|
1560 | matchedToOdd(subblossoms[ib]); |
---|
1561 | _tree_set->insert(subblossoms[ib], tree); |
---|
1562 | (*_blossom_data)[subblossoms[ib]].next = next; |
---|
1563 | (*_blossom_data)[subblossoms[ib]].pred = pred; |
---|
1564 | } |
---|
1565 | _tree_set->erase(blossom); |
---|
1566 | } |
---|
1567 | |
---|
1568 | void extractBlossom(int blossom, const Node& base, const Arc& matching) { |
---|
1569 | if (_blossom_set->trivial(blossom)) { |
---|
1570 | int bi = (*_node_index)[base]; |
---|
1571 | Value pot = (*_node_data)[bi].pot; |
---|
1572 | |
---|
1573 | (*_matching)[base] = matching; |
---|
1574 | _blossom_node_list.push_back(base); |
---|
1575 | (*_node_potential)[base] = pot; |
---|
1576 | } else { |
---|
1577 | |
---|
1578 | Value pot = (*_blossom_data)[blossom].pot; |
---|
1579 | int bn = _blossom_node_list.size(); |
---|
1580 | |
---|
1581 | std::vector<int> subblossoms; |
---|
1582 | _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
---|
1583 | int b = _blossom_set->find(base); |
---|
1584 | int ib = -1; |
---|
1585 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
1586 | if (subblossoms[i] == b) { ib = i; break; } |
---|
1587 | } |
---|
1588 | |
---|
1589 | for (int i = 1; i < int(subblossoms.size()); i += 2) { |
---|
1590 | int sb = subblossoms[(ib + i) % subblossoms.size()]; |
---|
1591 | int tb = subblossoms[(ib + i + 1) % subblossoms.size()]; |
---|
1592 | |
---|
1593 | Arc m = (*_blossom_data)[tb].next; |
---|
1594 | extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m)); |
---|
1595 | extractBlossom(tb, _graph.source(m), m); |
---|
1596 | } |
---|
1597 | extractBlossom(subblossoms[ib], base, matching); |
---|
1598 | |
---|
1599 | int en = _blossom_node_list.size(); |
---|
1600 | |
---|
1601 | _blossom_potential.push_back(BlossomVariable(bn, en, pot)); |
---|
1602 | } |
---|
1603 | } |
---|
1604 | |
---|
1605 | void extractMatching() { |
---|
1606 | std::vector<int> blossoms; |
---|
1607 | for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) { |
---|
1608 | blossoms.push_back(c); |
---|
1609 | } |
---|
1610 | |
---|
1611 | for (int i = 0; i < int(blossoms.size()); ++i) { |
---|
1612 | if ((*_blossom_data)[blossoms[i]].status == MATCHED) { |
---|
1613 | |
---|
1614 | Value offset = (*_blossom_data)[blossoms[i]].offset; |
---|
1615 | (*_blossom_data)[blossoms[i]].pot += 2 * offset; |
---|
1616 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]); |
---|
1617 | n != INVALID; ++n) { |
---|
1618 | (*_node_data)[(*_node_index)[n]].pot -= offset; |
---|
1619 | } |
---|
1620 | |
---|
1621 | Arc matching = (*_blossom_data)[blossoms[i]].next; |
---|
1622 | Node base = _graph.source(matching); |
---|
1623 | extractBlossom(blossoms[i], base, matching); |
---|
1624 | } else { |
---|
1625 | Node base = (*_blossom_data)[blossoms[i]].base; |
---|
1626 | extractBlossom(blossoms[i], base, INVALID); |
---|
1627 | } |
---|
1628 | } |
---|
1629 | } |
---|
1630 | |
---|
1631 | public: |
---|
1632 | |
---|
1633 | /// \brief Constructor |
---|
1634 | /// |
---|
1635 | /// Constructor. |
---|
1636 | MaxWeightedMatching(const Graph& graph, const WeightMap& weight) |
---|
1637 | : _graph(graph), _weight(weight), _matching(0), |
---|
1638 | _node_potential(0), _blossom_potential(), _blossom_node_list(), |
---|
1639 | _node_num(0), _blossom_num(0), |
---|
1640 | |
---|
1641 | _blossom_index(0), _blossom_set(0), _blossom_data(0), |
---|
1642 | _node_index(0), _node_heap_index(0), _node_data(0), |
---|
1643 | _tree_set_index(0), _tree_set(0), |
---|
1644 | |
---|
1645 | _delta1_index(0), _delta1(0), |
---|
1646 | _delta2_index(0), _delta2(0), |
---|
1647 | _delta3_index(0), _delta3(0), |
---|
1648 | _delta4_index(0), _delta4(0), |
---|
1649 | |
---|
1650 | _delta_sum() {} |
---|
1651 | |
---|
1652 | ~MaxWeightedMatching() { |
---|
1653 | destroyStructures(); |
---|
1654 | } |
---|
1655 | |
---|
1656 | /// \name Execution Control |
---|
1657 | /// The simplest way to execute the algorithm is to use the |
---|
1658 | /// \ref run() member function. |
---|
1659 | |
---|
1660 | ///@{ |
---|
1661 | |
---|
1662 | /// \brief Initialize the algorithm |
---|
1663 | /// |
---|
1664 | /// This function initializes the algorithm. |
---|
1665 | void init() { |
---|
1666 | createStructures(); |
---|
1667 | |
---|
1668 | for (ArcIt e(_graph); e != INVALID; ++e) { |
---|
1669 | (*_node_heap_index)[e] = BinHeap<Value, IntArcMap>::PRE_HEAP; |
---|
1670 | } |
---|
1671 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
1672 | (*_delta1_index)[n] = _delta1->PRE_HEAP; |
---|
1673 | } |
---|
1674 | for (EdgeIt e(_graph); e != INVALID; ++e) { |
---|
1675 | (*_delta3_index)[e] = _delta3->PRE_HEAP; |
---|
1676 | } |
---|
1677 | for (int i = 0; i < _blossom_num; ++i) { |
---|
1678 | (*_delta2_index)[i] = _delta2->PRE_HEAP; |
---|
1679 | (*_delta4_index)[i] = _delta4->PRE_HEAP; |
---|
1680 | } |
---|
1681 | |
---|
1682 | int index = 0; |
---|
1683 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
1684 | Value max = 0; |
---|
1685 | for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
---|
1686 | if (_graph.target(e) == n) continue; |
---|
1687 | if ((dualScale * _weight[e]) / 2 > max) { |
---|
1688 | max = (dualScale * _weight[e]) / 2; |
---|
1689 | } |
---|
1690 | } |
---|
1691 | (*_node_index)[n] = index; |
---|
1692 | (*_node_data)[index].pot = max; |
---|
1693 | _delta1->push(n, max); |
---|
1694 | int blossom = |
---|
1695 | _blossom_set->insert(n, std::numeric_limits<Value>::max()); |
---|
1696 | |
---|
1697 | _tree_set->insert(blossom); |
---|
1698 | |
---|
1699 | (*_blossom_data)[blossom].status = EVEN; |
---|
1700 | (*_blossom_data)[blossom].pred = INVALID; |
---|
1701 | (*_blossom_data)[blossom].next = INVALID; |
---|
1702 | (*_blossom_data)[blossom].pot = 0; |
---|
1703 | (*_blossom_data)[blossom].offset = 0; |
---|
1704 | ++index; |
---|
1705 | } |
---|
1706 | for (EdgeIt e(_graph); e != INVALID; ++e) { |
---|
1707 | int si = (*_node_index)[_graph.u(e)]; |
---|
1708 | int ti = (*_node_index)[_graph.v(e)]; |
---|
1709 | if (_graph.u(e) != _graph.v(e)) { |
---|
1710 | _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot - |
---|
1711 | dualScale * _weight[e]) / 2); |
---|
1712 | } |
---|
1713 | } |
---|
1714 | } |
---|
1715 | |
---|
1716 | /// \brief Start the algorithm |
---|
1717 | /// |
---|
1718 | /// This function starts the algorithm. |
---|
1719 | /// |
---|
1720 | /// \pre \ref init() must be called before using this function. |
---|
1721 | void start() { |
---|
1722 | enum OpType { |
---|
1723 | D1, D2, D3, D4 |
---|
1724 | }; |
---|
1725 | |
---|
1726 | int unmatched = _node_num; |
---|
1727 | while (unmatched > 0) { |
---|
1728 | Value d1 = !_delta1->empty() ? |
---|
1729 | _delta1->prio() : std::numeric_limits<Value>::max(); |
---|
1730 | |
---|
1731 | Value d2 = !_delta2->empty() ? |
---|
1732 | _delta2->prio() : std::numeric_limits<Value>::max(); |
---|
1733 | |
---|
1734 | Value d3 = !_delta3->empty() ? |
---|
1735 | _delta3->prio() : std::numeric_limits<Value>::max(); |
---|
1736 | |
---|
1737 | Value d4 = !_delta4->empty() ? |
---|
1738 | _delta4->prio() : std::numeric_limits<Value>::max(); |
---|
1739 | |
---|
1740 | _delta_sum = d1; OpType ot = D1; |
---|
1741 | if (d2 < _delta_sum) { _delta_sum = d2; ot = D2; } |
---|
1742 | if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; } |
---|
1743 | if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; } |
---|
1744 | |
---|
1745 | |
---|
1746 | switch (ot) { |
---|
1747 | case D1: |
---|
1748 | { |
---|
1749 | Node n = _delta1->top(); |
---|
1750 | unmatchNode(n); |
---|
1751 | --unmatched; |
---|
1752 | } |
---|
1753 | break; |
---|
1754 | case D2: |
---|
1755 | { |
---|
1756 | int blossom = _delta2->top(); |
---|
1757 | Node n = _blossom_set->classTop(blossom); |
---|
1758 | Arc e = (*_node_data)[(*_node_index)[n]].heap.top(); |
---|
1759 | extendOnArc(e); |
---|
1760 | } |
---|
1761 | break; |
---|
1762 | case D3: |
---|
1763 | { |
---|
1764 | Edge e = _delta3->top(); |
---|
1765 | |
---|
1766 | int left_blossom = _blossom_set->find(_graph.u(e)); |
---|
1767 | int right_blossom = _blossom_set->find(_graph.v(e)); |
---|
1768 | |
---|
1769 | if (left_blossom == right_blossom) { |
---|
1770 | _delta3->pop(); |
---|
1771 | } else { |
---|
1772 | int left_tree; |
---|
1773 | if ((*_blossom_data)[left_blossom].status == EVEN) { |
---|
1774 | left_tree = _tree_set->find(left_blossom); |
---|
1775 | } else { |
---|
1776 | left_tree = -1; |
---|
1777 | ++unmatched; |
---|
1778 | } |
---|
1779 | int right_tree; |
---|
1780 | if ((*_blossom_data)[right_blossom].status == EVEN) { |
---|
1781 | right_tree = _tree_set->find(right_blossom); |
---|
1782 | } else { |
---|
1783 | right_tree = -1; |
---|
1784 | ++unmatched; |
---|
1785 | } |
---|
1786 | |
---|
1787 | if (left_tree == right_tree) { |
---|
1788 | shrinkOnEdge(e, left_tree); |
---|
1789 | } else { |
---|
1790 | augmentOnEdge(e); |
---|
1791 | unmatched -= 2; |
---|
1792 | } |
---|
1793 | } |
---|
1794 | } break; |
---|
1795 | case D4: |
---|
1796 | splitBlossom(_delta4->top()); |
---|
1797 | break; |
---|
1798 | } |
---|
1799 | } |
---|
1800 | extractMatching(); |
---|
1801 | } |
---|
1802 | |
---|
1803 | /// \brief Run the algorithm. |
---|
1804 | /// |
---|
1805 | /// This method runs the \c %MaxWeightedMatching algorithm. |
---|
1806 | /// |
---|
1807 | /// \note mwm.run() is just a shortcut of the following code. |
---|
1808 | /// \code |
---|
1809 | /// mwm.init(); |
---|
1810 | /// mwm.start(); |
---|
1811 | /// \endcode |
---|
1812 | void run() { |
---|
1813 | init(); |
---|
1814 | start(); |
---|
1815 | } |
---|
1816 | |
---|
1817 | /// @} |
---|
1818 | |
---|
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. |
---|
1824 | |
---|
1825 | /// @{ |
---|
1826 | |
---|
1827 | /// \brief Return the weight of the matching. |
---|
1828 | /// |
---|
1829 | /// This function returns the weight of the found matching. |
---|
1830 | /// |
---|
1831 | /// \pre Either run() or start() must be called before using this function. |
---|
1832 | Value matchingValue() const { |
---|
1833 | Value sum = 0; |
---|
1834 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
1835 | if ((*_matching)[n] != INVALID) { |
---|
1836 | sum += _weight[(*_matching)[n]]; |
---|
1837 | } |
---|
1838 | } |
---|
1839 | return sum /= 2; |
---|
1840 | } |
---|
1841 | |
---|
1842 | /// \brief Return the size (cardinality) of the matching. |
---|
1843 | /// |
---|
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. |
---|
1847 | int matchingSize() const { |
---|
1848 | int num = 0; |
---|
1849 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
1850 | if ((*_matching)[n] != INVALID) { |
---|
1851 | ++num; |
---|
1852 | } |
---|
1853 | } |
---|
1854 | return num /= 2; |
---|
1855 | } |
---|
1856 | |
---|
1857 | /// \brief Return \c true if the given edge is in the matching. |
---|
1858 | /// |
---|
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. |
---|
1863 | bool matching(const Edge& edge) const { |
---|
1864 | return edge == (*_matching)[_graph.u(edge)]; |
---|
1865 | } |
---|
1866 | |
---|
1867 | /// \brief Return the matching arc (or edge) incident to the given node. |
---|
1868 | /// |
---|
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. |
---|
1874 | Arc matching(const Node& node) const { |
---|
1875 | return (*_matching)[node]; |
---|
1876 | } |
---|
1877 | |
---|
1878 | /// \brief Return the mate of the given node. |
---|
1879 | /// |
---|
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. |
---|
1884 | Node mate(const Node& node) const { |
---|
1885 | return (*_matching)[node] != INVALID ? |
---|
1886 | _graph.target((*_matching)[node]) : INVALID; |
---|
1887 | } |
---|
1888 | |
---|
1889 | /// @} |
---|
1890 | |
---|
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. |
---|
1895 | |
---|
1896 | /// @{ |
---|
1897 | |
---|
1898 | /// \brief Return the value of the dual solution. |
---|
1899 | /// |
---|
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. |
---|
1905 | Value dualValue() const { |
---|
1906 | Value sum = 0; |
---|
1907 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
1908 | sum += nodeValue(n); |
---|
1909 | } |
---|
1910 | for (int i = 0; i < blossomNum(); ++i) { |
---|
1911 | sum += blossomValue(i) * (blossomSize(i) / 2); |
---|
1912 | } |
---|
1913 | return sum; |
---|
1914 | } |
---|
1915 | |
---|
1916 | /// \brief Return the dual value (potential) of the given node. |
---|
1917 | /// |
---|
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. |
---|
1921 | Value nodeValue(const Node& n) const { |
---|
1922 | return (*_node_potential)[n]; |
---|
1923 | } |
---|
1924 | |
---|
1925 | /// \brief Return the number of the blossoms in the basis. |
---|
1926 | /// |
---|
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. |
---|
1930 | /// \see BlossomIt |
---|
1931 | int blossomNum() const { |
---|
1932 | return _blossom_potential.size(); |
---|
1933 | } |
---|
1934 | |
---|
1935 | /// \brief Return the number of the nodes in the given blossom. |
---|
1936 | /// |
---|
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 |
---|
1941 | int blossomSize(int k) const { |
---|
1942 | return _blossom_potential[k].end - _blossom_potential[k].begin; |
---|
1943 | } |
---|
1944 | |
---|
1945 | /// \brief Return the dual value (ptential) of the given blossom. |
---|
1946 | /// |
---|
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. |
---|
1950 | Value blossomValue(int k) const { |
---|
1951 | return _blossom_potential[k].value; |
---|
1952 | } |
---|
1953 | |
---|
1954 | /// \brief Iterator for obtaining the nodes of a blossom. |
---|
1955 | /// |
---|
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. |
---|
1960 | class BlossomIt { |
---|
1961 | public: |
---|
1962 | |
---|
1963 | /// \brief Constructor. |
---|
1964 | /// |
---|
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. |
---|
1970 | BlossomIt(const MaxWeightedMatching& algorithm, int variable) |
---|
1971 | : _algorithm(&algorithm) |
---|
1972 | { |
---|
1973 | _index = _algorithm->_blossom_potential[variable].begin; |
---|
1974 | _last = _algorithm->_blossom_potential[variable].end; |
---|
1975 | } |
---|
1976 | |
---|
1977 | /// \brief Conversion to \c Node. |
---|
1978 | /// |
---|
1979 | /// Conversion to \c Node. |
---|
1980 | operator Node() const { |
---|
1981 | return _algorithm->_blossom_node_list[_index]; |
---|
1982 | } |
---|
1983 | |
---|
1984 | /// \brief Increment operator. |
---|
1985 | /// |
---|
1986 | /// Increment operator. |
---|
1987 | BlossomIt& operator++() { |
---|
1988 | ++_index; |
---|
1989 | return *this; |
---|
1990 | } |
---|
1991 | |
---|
1992 | /// \brief Validity checking |
---|
1993 | /// |
---|
1994 | /// Checks whether the iterator is invalid. |
---|
1995 | bool operator==(Invalid) const { return _index == _last; } |
---|
1996 | |
---|
1997 | /// \brief Validity checking |
---|
1998 | /// |
---|
1999 | /// Checks whether the iterator is valid. |
---|
2000 | bool operator!=(Invalid) const { return _index != _last; } |
---|
2001 | |
---|
2002 | private: |
---|
2003 | const MaxWeightedMatching* _algorithm; |
---|
2004 | int _last; |
---|
2005 | int _index; |
---|
2006 | }; |
---|
2007 | |
---|
2008 | /// @} |
---|
2009 | |
---|
2010 | }; |
---|
2011 | |
---|
2012 | /// \ingroup matching |
---|
2013 | /// |
---|
2014 | /// \brief Weighted perfect matching in general graphs |
---|
2015 | /// |
---|
2016 | /// This class provides an efficient implementation of Edmond's |
---|
2017 | /// maximum weighted perfect matching algorithm. The implementation |
---|
2018 | /// is based on extensive use of priority queues and provides |
---|
2019 | /// \f$O(nm\log n)\f$ time complexity. |
---|
2020 | /// |
---|
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. |
---|
2025 | /// \f[ \sum_{e \in \delta(u)}x_e = 1 \quad \forall u\in V\f] |
---|
2026 | /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2} |
---|
2027 | \quad \forall B\in\mathcal{O}\f] */ |
---|
2028 | /// \f[x_e \ge 0\quad \forall e\in E\f] |
---|
2029 | /// \f[\max \sum_{e\in E}x_ew_e\f] |
---|
2030 | /// where \f$\delta(X)\f$ is the set of edges incident to a node in |
---|
2031 | /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in |
---|
2032 | /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality |
---|
2033 | /// subsets of the nodes. |
---|
2034 | /// |
---|
2035 | /// The algorithm calculates an optimal matching and a proof of the |
---|
2036 | /// optimality. The solution of the dual problem can be used to check |
---|
2037 | /// the result of the algorithm. The dual linear problem is the |
---|
2038 | /// following. |
---|
2039 | /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}z_B \ge |
---|
2040 | w_{uv} \quad \forall uv\in E\f] */ |
---|
2041 | /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f] |
---|
2042 | /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}} |
---|
2043 | \frac{\vert B \vert - 1}{2}z_B\f] */ |
---|
2044 | /// |
---|
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 |
---|
2059 | template <typename GR, |
---|
2060 | typename WM = typename GR::template EdgeMap<int> > |
---|
2061 | #endif |
---|
2062 | class MaxWeightedPerfectMatching { |
---|
2063 | public: |
---|
2064 | |
---|
2065 | /// The graph type of the algorithm |
---|
2066 | typedef GR Graph; |
---|
2067 | /// The type of the edge weight map |
---|
2068 | typedef WM WeightMap; |
---|
2069 | /// The value type of the edge weights |
---|
2070 | typedef typename WeightMap::Value Value; |
---|
2071 | |
---|
2072 | /// \brief Scaling factor for dual solution |
---|
2073 | /// |
---|
2074 | /// Scaling factor for dual solution, it is equal to 4 or 1 |
---|
2075 | /// according to the value type. |
---|
2076 | static const int dualScale = |
---|
2077 | std::numeric_limits<Value>::is_integer ? 4 : 1; |
---|
2078 | |
---|
2079 | typedef typename Graph::template NodeMap<typename Graph::Arc> |
---|
2080 | MatchingMap; |
---|
2081 | |
---|
2082 | private: |
---|
2083 | |
---|
2084 | TEMPLATE_GRAPH_TYPEDEFS(Graph); |
---|
2085 | |
---|
2086 | typedef typename Graph::template NodeMap<Value> NodePotential; |
---|
2087 | typedef std::vector<Node> BlossomNodeList; |
---|
2088 | |
---|
2089 | struct BlossomVariable { |
---|
2090 | int begin, end; |
---|
2091 | Value value; |
---|
2092 | |
---|
2093 | BlossomVariable(int _begin, int _end, Value _value) |
---|
2094 | : begin(_begin), end(_end), value(_value) {} |
---|
2095 | |
---|
2096 | }; |
---|
2097 | |
---|
2098 | typedef std::vector<BlossomVariable> BlossomPotential; |
---|
2099 | |
---|
2100 | const Graph& _graph; |
---|
2101 | const WeightMap& _weight; |
---|
2102 | |
---|
2103 | MatchingMap* _matching; |
---|
2104 | |
---|
2105 | NodePotential* _node_potential; |
---|
2106 | |
---|
2107 | BlossomPotential _blossom_potential; |
---|
2108 | BlossomNodeList _blossom_node_list; |
---|
2109 | |
---|
2110 | int _node_num; |
---|
2111 | int _blossom_num; |
---|
2112 | |
---|
2113 | typedef RangeMap<int> IntIntMap; |
---|
2114 | |
---|
2115 | enum Status { |
---|
2116 | EVEN = -1, MATCHED = 0, ODD = 1 |
---|
2117 | }; |
---|
2118 | |
---|
2119 | typedef HeapUnionFind<Value, IntNodeMap> BlossomSet; |
---|
2120 | struct BlossomData { |
---|
2121 | int tree; |
---|
2122 | Status status; |
---|
2123 | Arc pred, next; |
---|
2124 | Value pot, offset; |
---|
2125 | }; |
---|
2126 | |
---|
2127 | IntNodeMap *_blossom_index; |
---|
2128 | BlossomSet *_blossom_set; |
---|
2129 | RangeMap<BlossomData>* _blossom_data; |
---|
2130 | |
---|
2131 | IntNodeMap *_node_index; |
---|
2132 | IntArcMap *_node_heap_index; |
---|
2133 | |
---|
2134 | struct NodeData { |
---|
2135 | |
---|
2136 | NodeData(IntArcMap& node_heap_index) |
---|
2137 | : heap(node_heap_index) {} |
---|
2138 | |
---|
2139 | int blossom; |
---|
2140 | Value pot; |
---|
2141 | BinHeap<Value, IntArcMap> heap; |
---|
2142 | std::map<int, Arc> heap_index; |
---|
2143 | |
---|
2144 | int tree; |
---|
2145 | }; |
---|
2146 | |
---|
2147 | RangeMap<NodeData>* _node_data; |
---|
2148 | |
---|
2149 | typedef ExtendFindEnum<IntIntMap> TreeSet; |
---|
2150 | |
---|
2151 | IntIntMap *_tree_set_index; |
---|
2152 | TreeSet *_tree_set; |
---|
2153 | |
---|
2154 | IntIntMap *_delta2_index; |
---|
2155 | BinHeap<Value, IntIntMap> *_delta2; |
---|
2156 | |
---|
2157 | IntEdgeMap *_delta3_index; |
---|
2158 | BinHeap<Value, IntEdgeMap> *_delta3; |
---|
2159 | |
---|
2160 | IntIntMap *_delta4_index; |
---|
2161 | BinHeap<Value, IntIntMap> *_delta4; |
---|
2162 | |
---|
2163 | Value _delta_sum; |
---|
2164 | |
---|
2165 | void createStructures() { |
---|
2166 | _node_num = countNodes(_graph); |
---|
2167 | _blossom_num = _node_num * 3 / 2; |
---|
2168 | |
---|
2169 | if (!_matching) { |
---|
2170 | _matching = new MatchingMap(_graph); |
---|
2171 | } |
---|
2172 | if (!_node_potential) { |
---|
2173 | _node_potential = new NodePotential(_graph); |
---|
2174 | } |
---|
2175 | if (!_blossom_set) { |
---|
2176 | _blossom_index = new IntNodeMap(_graph); |
---|
2177 | _blossom_set = new BlossomSet(*_blossom_index); |
---|
2178 | _blossom_data = new RangeMap<BlossomData>(_blossom_num); |
---|
2179 | } |
---|
2180 | |
---|
2181 | if (!_node_index) { |
---|
2182 | _node_index = new IntNodeMap(_graph); |
---|
2183 | _node_heap_index = new IntArcMap(_graph); |
---|
2184 | _node_data = new RangeMap<NodeData>(_node_num, |
---|
2185 | NodeData(*_node_heap_index)); |
---|
2186 | } |
---|
2187 | |
---|
2188 | if (!_tree_set) { |
---|
2189 | _tree_set_index = new IntIntMap(_blossom_num); |
---|
2190 | _tree_set = new TreeSet(*_tree_set_index); |
---|
2191 | } |
---|
2192 | if (!_delta2) { |
---|
2193 | _delta2_index = new IntIntMap(_blossom_num); |
---|
2194 | _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index); |
---|
2195 | } |
---|
2196 | if (!_delta3) { |
---|
2197 | _delta3_index = new IntEdgeMap(_graph); |
---|
2198 | _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index); |
---|
2199 | } |
---|
2200 | if (!_delta4) { |
---|
2201 | _delta4_index = new IntIntMap(_blossom_num); |
---|
2202 | _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index); |
---|
2203 | } |
---|
2204 | } |
---|
2205 | |
---|
2206 | void destroyStructures() { |
---|
2207 | _node_num = countNodes(_graph); |
---|
2208 | _blossom_num = _node_num * 3 / 2; |
---|
2209 | |
---|
2210 | if (_matching) { |
---|
2211 | delete _matching; |
---|
2212 | } |
---|
2213 | if (_node_potential) { |
---|
2214 | delete _node_potential; |
---|
2215 | } |
---|
2216 | if (_blossom_set) { |
---|
2217 | delete _blossom_index; |
---|
2218 | delete _blossom_set; |
---|
2219 | delete _blossom_data; |
---|
2220 | } |
---|
2221 | |
---|
2222 | if (_node_index) { |
---|
2223 | delete _node_index; |
---|
2224 | delete _node_heap_index; |
---|
2225 | delete _node_data; |
---|
2226 | } |
---|
2227 | |
---|
2228 | if (_tree_set) { |
---|
2229 | delete _tree_set_index; |
---|
2230 | delete _tree_set; |
---|
2231 | } |
---|
2232 | if (_delta2) { |
---|
2233 | delete _delta2_index; |
---|
2234 | delete _delta2; |
---|
2235 | } |
---|
2236 | if (_delta3) { |
---|
2237 | delete _delta3_index; |
---|
2238 | delete _delta3; |
---|
2239 | } |
---|
2240 | if (_delta4) { |
---|
2241 | delete _delta4_index; |
---|
2242 | delete _delta4; |
---|
2243 | } |
---|
2244 | } |
---|
2245 | |
---|
2246 | void matchedToEven(int blossom, int tree) { |
---|
2247 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
2248 | _delta2->erase(blossom); |
---|
2249 | } |
---|
2250 | |
---|
2251 | if (!_blossom_set->trivial(blossom)) { |
---|
2252 | (*_blossom_data)[blossom].pot -= |
---|
2253 | 2 * (_delta_sum - (*_blossom_data)[blossom].offset); |
---|
2254 | } |
---|
2255 | |
---|
2256 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
2257 | n != INVALID; ++n) { |
---|
2258 | |
---|
2259 | _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
---|
2260 | int ni = (*_node_index)[n]; |
---|
2261 | |
---|
2262 | (*_node_data)[ni].heap.clear(); |
---|
2263 | (*_node_data)[ni].heap_index.clear(); |
---|
2264 | |
---|
2265 | (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset; |
---|
2266 | |
---|
2267 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
2268 | Node v = _graph.source(e); |
---|
2269 | int vb = _blossom_set->find(v); |
---|
2270 | int vi = (*_node_index)[v]; |
---|
2271 | |
---|
2272 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
2273 | dualScale * _weight[e]; |
---|
2274 | |
---|
2275 | if ((*_blossom_data)[vb].status == EVEN) { |
---|
2276 | if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
---|
2277 | _delta3->push(e, rw / 2); |
---|
2278 | } |
---|
2279 | } else { |
---|
2280 | typename std::map<int, Arc>::iterator it = |
---|
2281 | (*_node_data)[vi].heap_index.find(tree); |
---|
2282 | |
---|
2283 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
2284 | if ((*_node_data)[vi].heap[it->second] > rw) { |
---|
2285 | (*_node_data)[vi].heap.replace(it->second, e); |
---|
2286 | (*_node_data)[vi].heap.decrease(e, rw); |
---|
2287 | it->second = e; |
---|
2288 | } |
---|
2289 | } else { |
---|
2290 | (*_node_data)[vi].heap.push(e, rw); |
---|
2291 | (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
---|
2292 | } |
---|
2293 | |
---|
2294 | if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
---|
2295 | _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
---|
2296 | |
---|
2297 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
2298 | if (_delta2->state(vb) != _delta2->IN_HEAP) { |
---|
2299 | _delta2->push(vb, _blossom_set->classPrio(vb) - |
---|
2300 | (*_blossom_data)[vb].offset); |
---|
2301 | } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
---|
2302 | (*_blossom_data)[vb].offset){ |
---|
2303 | _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
---|
2304 | (*_blossom_data)[vb].offset); |
---|
2305 | } |
---|
2306 | } |
---|
2307 | } |
---|
2308 | } |
---|
2309 | } |
---|
2310 | } |
---|
2311 | (*_blossom_data)[blossom].offset = 0; |
---|
2312 | } |
---|
2313 | |
---|
2314 | void matchedToOdd(int blossom) { |
---|
2315 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
2316 | _delta2->erase(blossom); |
---|
2317 | } |
---|
2318 | (*_blossom_data)[blossom].offset += _delta_sum; |
---|
2319 | if (!_blossom_set->trivial(blossom)) { |
---|
2320 | _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 + |
---|
2321 | (*_blossom_data)[blossom].offset); |
---|
2322 | } |
---|
2323 | } |
---|
2324 | |
---|
2325 | void evenToMatched(int blossom, int tree) { |
---|
2326 | if (!_blossom_set->trivial(blossom)) { |
---|
2327 | (*_blossom_data)[blossom].pot += 2 * _delta_sum; |
---|
2328 | } |
---|
2329 | |
---|
2330 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
2331 | n != INVALID; ++n) { |
---|
2332 | int ni = (*_node_index)[n]; |
---|
2333 | (*_node_data)[ni].pot -= _delta_sum; |
---|
2334 | |
---|
2335 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
2336 | Node v = _graph.source(e); |
---|
2337 | int vb = _blossom_set->find(v); |
---|
2338 | int vi = (*_node_index)[v]; |
---|
2339 | |
---|
2340 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
2341 | dualScale * _weight[e]; |
---|
2342 | |
---|
2343 | if (vb == blossom) { |
---|
2344 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
2345 | _delta3->erase(e); |
---|
2346 | } |
---|
2347 | } else if ((*_blossom_data)[vb].status == EVEN) { |
---|
2348 | |
---|
2349 | if (_delta3->state(e) == _delta3->IN_HEAP) { |
---|
2350 | _delta3->erase(e); |
---|
2351 | } |
---|
2352 | |
---|
2353 | int vt = _tree_set->find(vb); |
---|
2354 | |
---|
2355 | if (vt != tree) { |
---|
2356 | |
---|
2357 | Arc r = _graph.oppositeArc(e); |
---|
2358 | |
---|
2359 | typename std::map<int, Arc>::iterator it = |
---|
2360 | (*_node_data)[ni].heap_index.find(vt); |
---|
2361 | |
---|
2362 | if (it != (*_node_data)[ni].heap_index.end()) { |
---|
2363 | if ((*_node_data)[ni].heap[it->second] > rw) { |
---|
2364 | (*_node_data)[ni].heap.replace(it->second, r); |
---|
2365 | (*_node_data)[ni].heap.decrease(r, rw); |
---|
2366 | it->second = r; |
---|
2367 | } |
---|
2368 | } else { |
---|
2369 | (*_node_data)[ni].heap.push(r, rw); |
---|
2370 | (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
---|
2371 | } |
---|
2372 | |
---|
2373 | if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
---|
2374 | _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
---|
2375 | |
---|
2376 | if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
---|
2377 | _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
---|
2378 | (*_blossom_data)[blossom].offset); |
---|
2379 | } else if ((*_delta2)[blossom] > |
---|
2380 | _blossom_set->classPrio(blossom) - |
---|
2381 | (*_blossom_data)[blossom].offset){ |
---|
2382 | _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
---|
2383 | (*_blossom_data)[blossom].offset); |
---|
2384 | } |
---|
2385 | } |
---|
2386 | } |
---|
2387 | } else { |
---|
2388 | |
---|
2389 | typename std::map<int, Arc>::iterator it = |
---|
2390 | (*_node_data)[vi].heap_index.find(tree); |
---|
2391 | |
---|
2392 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
2393 | (*_node_data)[vi].heap.erase(it->second); |
---|
2394 | (*_node_data)[vi].heap_index.erase(it); |
---|
2395 | if ((*_node_data)[vi].heap.empty()) { |
---|
2396 | _blossom_set->increase(v, std::numeric_limits<Value>::max()); |
---|
2397 | } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) { |
---|
2398 | _blossom_set->increase(v, (*_node_data)[vi].heap.prio()); |
---|
2399 | } |
---|
2400 | |
---|
2401 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
2402 | if (_blossom_set->classPrio(vb) == |
---|
2403 | std::numeric_limits<Value>::max()) { |
---|
2404 | _delta2->erase(vb); |
---|
2405 | } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) - |
---|
2406 | (*_blossom_data)[vb].offset) { |
---|
2407 | _delta2->increase(vb, _blossom_set->classPrio(vb) - |
---|
2408 | (*_blossom_data)[vb].offset); |
---|
2409 | } |
---|
2410 | } |
---|
2411 | } |
---|
2412 | } |
---|
2413 | } |
---|
2414 | } |
---|
2415 | } |
---|
2416 | |
---|
2417 | void oddToMatched(int blossom) { |
---|
2418 | (*_blossom_data)[blossom].offset -= _delta_sum; |
---|
2419 | |
---|
2420 | if (_blossom_set->classPrio(blossom) != |
---|
2421 | std::numeric_limits<Value>::max()) { |
---|
2422 | _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
---|
2423 | (*_blossom_data)[blossom].offset); |
---|
2424 | } |
---|
2425 | |
---|
2426 | if (!_blossom_set->trivial(blossom)) { |
---|
2427 | _delta4->erase(blossom); |
---|
2428 | } |
---|
2429 | } |
---|
2430 | |
---|
2431 | void oddToEven(int blossom, int tree) { |
---|
2432 | if (!_blossom_set->trivial(blossom)) { |
---|
2433 | _delta4->erase(blossom); |
---|
2434 | (*_blossom_data)[blossom].pot -= |
---|
2435 | 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset); |
---|
2436 | } |
---|
2437 | |
---|
2438 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
---|
2439 | n != INVALID; ++n) { |
---|
2440 | int ni = (*_node_index)[n]; |
---|
2441 | |
---|
2442 | _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
---|
2443 | |
---|
2444 | (*_node_data)[ni].heap.clear(); |
---|
2445 | (*_node_data)[ni].heap_index.clear(); |
---|
2446 | (*_node_data)[ni].pot += |
---|
2447 | 2 * _delta_sum - (*_blossom_data)[blossom].offset; |
---|
2448 | |
---|
2449 | for (InArcIt e(_graph, n); e != INVALID; ++e) { |
---|
2450 | Node v = _graph.source(e); |
---|
2451 | int vb = _blossom_set->find(v); |
---|
2452 | int vi = (*_node_index)[v]; |
---|
2453 | |
---|
2454 | Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
---|
2455 | dualScale * _weight[e]; |
---|
2456 | |
---|
2457 | if ((*_blossom_data)[vb].status == EVEN) { |
---|
2458 | if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
---|
2459 | _delta3->push(e, rw / 2); |
---|
2460 | } |
---|
2461 | } else { |
---|
2462 | |
---|
2463 | typename std::map<int, Arc>::iterator it = |
---|
2464 | (*_node_data)[vi].heap_index.find(tree); |
---|
2465 | |
---|
2466 | if (it != (*_node_data)[vi].heap_index.end()) { |
---|
2467 | if ((*_node_data)[vi].heap[it->second] > rw) { |
---|
2468 | (*_node_data)[vi].heap.replace(it->second, e); |
---|
2469 | (*_node_data)[vi].heap.decrease(e, rw); |
---|
2470 | it->second = e; |
---|
2471 | } |
---|
2472 | } else { |
---|
2473 | (*_node_data)[vi].heap.push(e, rw); |
---|
2474 | (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
---|
2475 | } |
---|
2476 | |
---|
2477 | if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
---|
2478 | _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
---|
2479 | |
---|
2480 | if ((*_blossom_data)[vb].status == MATCHED) { |
---|
2481 | if (_delta2->state(vb) != _delta2->IN_HEAP) { |
---|
2482 | _delta2->push(vb, _blossom_set->classPrio(vb) - |
---|
2483 | (*_blossom_data)[vb].offset); |
---|
2484 | } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
---|
2485 | (*_blossom_data)[vb].offset) { |
---|
2486 | _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
---|
2487 | (*_blossom_data)[vb].offset); |
---|
2488 | } |
---|
2489 | } |
---|
2490 | } |
---|
2491 | } |
---|
2492 | } |
---|
2493 | } |
---|
2494 | (*_blossom_data)[blossom].offset = 0; |
---|
2495 | } |
---|
2496 | |
---|
2497 | void alternatePath(int even, int tree) { |
---|
2498 | int odd; |
---|
2499 | |
---|
2500 | evenToMatched(even, tree); |
---|
2501 | (*_blossom_data)[even].status = MATCHED; |
---|
2502 | |
---|
2503 | while ((*_blossom_data)[even].pred != INVALID) { |
---|
2504 | odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred)); |
---|
2505 | (*_blossom_data)[odd].status = MATCHED; |
---|
2506 | oddToMatched(odd); |
---|
2507 | (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred; |
---|
2508 | |
---|
2509 | even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred)); |
---|
2510 | (*_blossom_data)[even].status = MATCHED; |
---|
2511 | evenToMatched(even, tree); |
---|
2512 | (*_blossom_data)[even].next = |
---|
2513 | _graph.oppositeArc((*_blossom_data)[odd].pred); |
---|
2514 | } |
---|
2515 | |
---|
2516 | } |
---|
2517 | |
---|
2518 | void destroyTree(int tree) { |
---|
2519 | for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) { |
---|
2520 | if ((*_blossom_data)[b].status == EVEN) { |
---|
2521 | (*_blossom_data)[b].status = MATCHED; |
---|
2522 | evenToMatched(b, tree); |
---|
2523 | } else if ((*_blossom_data)[b].status == ODD) { |
---|
2524 | (*_blossom_data)[b].status = MATCHED; |
---|
2525 | oddToMatched(b); |
---|
2526 | } |
---|
2527 | } |
---|
2528 | _tree_set->eraseClass(tree); |
---|
2529 | } |
---|
2530 | |
---|
2531 | void augmentOnEdge(const Edge& edge) { |
---|
2532 | |
---|
2533 | int left = _blossom_set->find(_graph.u(edge)); |
---|
2534 | int right = _blossom_set->find(_graph.v(edge)); |
---|
2535 | |
---|
2536 | int left_tree = _tree_set->find(left); |
---|
2537 | alternatePath(left, left_tree); |
---|
2538 | destroyTree(left_tree); |
---|
2539 | |
---|
2540 | int right_tree = _tree_set->find(right); |
---|
2541 | alternatePath(right, right_tree); |
---|
2542 | destroyTree(right_tree); |
---|
2543 | |
---|
2544 | (*_blossom_data)[left].next = _graph.direct(edge, true); |
---|
2545 | (*_blossom_data)[right].next = _graph.direct(edge, false); |
---|
2546 | } |
---|
2547 | |
---|
2548 | void extendOnArc(const Arc& arc) { |
---|
2549 | int base = _blossom_set->find(_graph.target(arc)); |
---|
2550 | int tree = _tree_set->find(base); |
---|
2551 | |
---|
2552 | int odd = _blossom_set->find(_graph.source(arc)); |
---|
2553 | _tree_set->insert(odd, tree); |
---|
2554 | (*_blossom_data)[odd].status = ODD; |
---|
2555 | matchedToOdd(odd); |
---|
2556 | (*_blossom_data)[odd].pred = arc; |
---|
2557 | |
---|
2558 | int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next)); |
---|
2559 | (*_blossom_data)[even].pred = (*_blossom_data)[even].next; |
---|
2560 | _tree_set->insert(even, tree); |
---|
2561 | (*_blossom_data)[even].status = EVEN; |
---|
2562 | matchedToEven(even, tree); |
---|
2563 | } |
---|
2564 | |
---|
2565 | void shrinkOnEdge(const Edge& edge, int tree) { |
---|
2566 | int nca = -1; |
---|
2567 | std::vector<int> left_path, right_path; |
---|
2568 | |
---|
2569 | { |
---|
2570 | std::set<int> left_set, right_set; |
---|
2571 | int left = _blossom_set->find(_graph.u(edge)); |
---|
2572 | left_path.push_back(left); |
---|
2573 | left_set.insert(left); |
---|
2574 | |
---|
2575 | int right = _blossom_set->find(_graph.v(edge)); |
---|
2576 | right_path.push_back(right); |
---|
2577 | right_set.insert(right); |
---|
2578 | |
---|
2579 | while (true) { |
---|
2580 | |
---|
2581 | if ((*_blossom_data)[left].pred == INVALID) break; |
---|
2582 | |
---|
2583 | left = |
---|
2584 | _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
---|
2585 | left_path.push_back(left); |
---|
2586 | left = |
---|
2587 | _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
---|
2588 | left_path.push_back(left); |
---|
2589 | |
---|
2590 | left_set.insert(left); |
---|
2591 | |
---|
2592 | if (right_set.find(left) != right_set.end()) { |
---|
2593 | nca = left; |
---|
2594 | break; |
---|
2595 | } |
---|
2596 | |
---|
2597 | if ((*_blossom_data)[right].pred == INVALID) break; |
---|
2598 | |
---|
2599 | right = |
---|
2600 | _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
---|
2601 | right_path.push_back(right); |
---|
2602 | right = |
---|
2603 | _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
---|
2604 | right_path.push_back(right); |
---|
2605 | |
---|
2606 | right_set.insert(right); |
---|
2607 | |
---|
2608 | if (left_set.find(right) != left_set.end()) { |
---|
2609 | nca = right; |
---|
2610 | break; |
---|
2611 | } |
---|
2612 | |
---|
2613 | } |
---|
2614 | |
---|
2615 | if (nca == -1) { |
---|
2616 | if ((*_blossom_data)[left].pred == INVALID) { |
---|
2617 | nca = right; |
---|
2618 | while (left_set.find(nca) == left_set.end()) { |
---|
2619 | nca = |
---|
2620 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
2621 | right_path.push_back(nca); |
---|
2622 | nca = |
---|
2623 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
2624 | right_path.push_back(nca); |
---|
2625 | } |
---|
2626 | } else { |
---|
2627 | nca = left; |
---|
2628 | while (right_set.find(nca) == right_set.end()) { |
---|
2629 | nca = |
---|
2630 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
2631 | left_path.push_back(nca); |
---|
2632 | nca = |
---|
2633 | _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
---|
2634 | left_path.push_back(nca); |
---|
2635 | } |
---|
2636 | } |
---|
2637 | } |
---|
2638 | } |
---|
2639 | |
---|
2640 | std::vector<int> subblossoms; |
---|
2641 | Arc prev; |
---|
2642 | |
---|
2643 | prev = _graph.direct(edge, true); |
---|
2644 | for (int i = 0; left_path[i] != nca; i += 2) { |
---|
2645 | subblossoms.push_back(left_path[i]); |
---|
2646 | (*_blossom_data)[left_path[i]].next = prev; |
---|
2647 | _tree_set->erase(left_path[i]); |
---|
2648 | |
---|
2649 | subblossoms.push_back(left_path[i + 1]); |
---|
2650 | (*_blossom_data)[left_path[i + 1]].status = EVEN; |
---|
2651 | oddToEven(left_path[i + 1], tree); |
---|
2652 | _tree_set->erase(left_path[i + 1]); |
---|
2653 | prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred); |
---|
2654 | } |
---|
2655 | |
---|
2656 | int k = 0; |
---|
2657 | while (right_path[k] != nca) ++k; |
---|
2658 | |
---|
2659 | subblossoms.push_back(nca); |
---|
2660 | (*_blossom_data)[nca].next = prev; |
---|
2661 | |
---|
2662 | for (int i = k - 2; i >= 0; i -= 2) { |
---|
2663 | subblossoms.push_back(right_path[i + 1]); |
---|
2664 | (*_blossom_data)[right_path[i + 1]].status = EVEN; |
---|
2665 | oddToEven(right_path[i + 1], tree); |
---|
2666 | _tree_set->erase(right_path[i + 1]); |
---|
2667 | |
---|
2668 | (*_blossom_data)[right_path[i + 1]].next = |
---|
2669 | (*_blossom_data)[right_path[i + 1]].pred; |
---|
2670 | |
---|
2671 | subblossoms.push_back(right_path[i]); |
---|
2672 | _tree_set->erase(right_path[i]); |
---|
2673 | } |
---|
2674 | |
---|
2675 | int surface = |
---|
2676 | _blossom_set->join(subblossoms.begin(), subblossoms.end()); |
---|
2677 | |
---|
2678 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
2679 | if (!_blossom_set->trivial(subblossoms[i])) { |
---|
2680 | (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum; |
---|
2681 | } |
---|
2682 | (*_blossom_data)[subblossoms[i]].status = MATCHED; |
---|
2683 | } |
---|
2684 | |
---|
2685 | (*_blossom_data)[surface].pot = -2 * _delta_sum; |
---|
2686 | (*_blossom_data)[surface].offset = 0; |
---|
2687 | (*_blossom_data)[surface].status = EVEN; |
---|
2688 | (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred; |
---|
2689 | (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred; |
---|
2690 | |
---|
2691 | _tree_set->insert(surface, tree); |
---|
2692 | _tree_set->erase(nca); |
---|
2693 | } |
---|
2694 | |
---|
2695 | void splitBlossom(int blossom) { |
---|
2696 | Arc next = (*_blossom_data)[blossom].next; |
---|
2697 | Arc pred = (*_blossom_data)[blossom].pred; |
---|
2698 | |
---|
2699 | int tree = _tree_set->find(blossom); |
---|
2700 | |
---|
2701 | (*_blossom_data)[blossom].status = MATCHED; |
---|
2702 | oddToMatched(blossom); |
---|
2703 | if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
---|
2704 | _delta2->erase(blossom); |
---|
2705 | } |
---|
2706 | |
---|
2707 | std::vector<int> subblossoms; |
---|
2708 | _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
---|
2709 | |
---|
2710 | Value offset = (*_blossom_data)[blossom].offset; |
---|
2711 | int b = _blossom_set->find(_graph.source(pred)); |
---|
2712 | int d = _blossom_set->find(_graph.source(next)); |
---|
2713 | |
---|
2714 | int ib = -1, id = -1; |
---|
2715 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
2716 | if (subblossoms[i] == b) ib = i; |
---|
2717 | if (subblossoms[i] == d) id = i; |
---|
2718 | |
---|
2719 | (*_blossom_data)[subblossoms[i]].offset = offset; |
---|
2720 | if (!_blossom_set->trivial(subblossoms[i])) { |
---|
2721 | (*_blossom_data)[subblossoms[i]].pot -= 2 * offset; |
---|
2722 | } |
---|
2723 | if (_blossom_set->classPrio(subblossoms[i]) != |
---|
2724 | std::numeric_limits<Value>::max()) { |
---|
2725 | _delta2->push(subblossoms[i], |
---|
2726 | _blossom_set->classPrio(subblossoms[i]) - |
---|
2727 | (*_blossom_data)[subblossoms[i]].offset); |
---|
2728 | } |
---|
2729 | } |
---|
2730 | |
---|
2731 | if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) { |
---|
2732 | for (int i = (id + 1) % subblossoms.size(); |
---|
2733 | i != ib; i = (i + 2) % subblossoms.size()) { |
---|
2734 | int sb = subblossoms[i]; |
---|
2735 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
2736 | (*_blossom_data)[sb].next = |
---|
2737 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
2738 | } |
---|
2739 | |
---|
2740 | for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) { |
---|
2741 | int sb = subblossoms[i]; |
---|
2742 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
2743 | int ub = subblossoms[(i + 2) % subblossoms.size()]; |
---|
2744 | |
---|
2745 | (*_blossom_data)[sb].status = ODD; |
---|
2746 | matchedToOdd(sb); |
---|
2747 | _tree_set->insert(sb, tree); |
---|
2748 | (*_blossom_data)[sb].pred = pred; |
---|
2749 | (*_blossom_data)[sb].next = |
---|
2750 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
2751 | |
---|
2752 | pred = (*_blossom_data)[ub].next; |
---|
2753 | |
---|
2754 | (*_blossom_data)[tb].status = EVEN; |
---|
2755 | matchedToEven(tb, tree); |
---|
2756 | _tree_set->insert(tb, tree); |
---|
2757 | (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next; |
---|
2758 | } |
---|
2759 | |
---|
2760 | (*_blossom_data)[subblossoms[id]].status = ODD; |
---|
2761 | matchedToOdd(subblossoms[id]); |
---|
2762 | _tree_set->insert(subblossoms[id], tree); |
---|
2763 | (*_blossom_data)[subblossoms[id]].next = next; |
---|
2764 | (*_blossom_data)[subblossoms[id]].pred = pred; |
---|
2765 | |
---|
2766 | } else { |
---|
2767 | |
---|
2768 | for (int i = (ib + 1) % subblossoms.size(); |
---|
2769 | i != id; i = (i + 2) % subblossoms.size()) { |
---|
2770 | int sb = subblossoms[i]; |
---|
2771 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
2772 | (*_blossom_data)[sb].next = |
---|
2773 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
2774 | } |
---|
2775 | |
---|
2776 | for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) { |
---|
2777 | int sb = subblossoms[i]; |
---|
2778 | int tb = subblossoms[(i + 1) % subblossoms.size()]; |
---|
2779 | int ub = subblossoms[(i + 2) % subblossoms.size()]; |
---|
2780 | |
---|
2781 | (*_blossom_data)[sb].status = ODD; |
---|
2782 | matchedToOdd(sb); |
---|
2783 | _tree_set->insert(sb, tree); |
---|
2784 | (*_blossom_data)[sb].next = next; |
---|
2785 | (*_blossom_data)[sb].pred = |
---|
2786 | _graph.oppositeArc((*_blossom_data)[tb].next); |
---|
2787 | |
---|
2788 | (*_blossom_data)[tb].status = EVEN; |
---|
2789 | matchedToEven(tb, tree); |
---|
2790 | _tree_set->insert(tb, tree); |
---|
2791 | (*_blossom_data)[tb].pred = |
---|
2792 | (*_blossom_data)[tb].next = |
---|
2793 | _graph.oppositeArc((*_blossom_data)[ub].next); |
---|
2794 | next = (*_blossom_data)[ub].next; |
---|
2795 | } |
---|
2796 | |
---|
2797 | (*_blossom_data)[subblossoms[ib]].status = ODD; |
---|
2798 | matchedToOdd(subblossoms[ib]); |
---|
2799 | _tree_set->insert(subblossoms[ib], tree); |
---|
2800 | (*_blossom_data)[subblossoms[ib]].next = next; |
---|
2801 | (*_blossom_data)[subblossoms[ib]].pred = pred; |
---|
2802 | } |
---|
2803 | _tree_set->erase(blossom); |
---|
2804 | } |
---|
2805 | |
---|
2806 | void extractBlossom(int blossom, const Node& base, const Arc& matching) { |
---|
2807 | if (_blossom_set->trivial(blossom)) { |
---|
2808 | int bi = (*_node_index)[base]; |
---|
2809 | Value pot = (*_node_data)[bi].pot; |
---|
2810 | |
---|
2811 | (*_matching)[base] = matching; |
---|
2812 | _blossom_node_list.push_back(base); |
---|
2813 | (*_node_potential)[base] = pot; |
---|
2814 | } else { |
---|
2815 | |
---|
2816 | Value pot = (*_blossom_data)[blossom].pot; |
---|
2817 | int bn = _blossom_node_list.size(); |
---|
2818 | |
---|
2819 | std::vector<int> subblossoms; |
---|
2820 | _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
---|
2821 | int b = _blossom_set->find(base); |
---|
2822 | int ib = -1; |
---|
2823 | for (int i = 0; i < int(subblossoms.size()); ++i) { |
---|
2824 | if (subblossoms[i] == b) { ib = i; break; } |
---|
2825 | } |
---|
2826 | |
---|
2827 | for (int i = 1; i < int(subblossoms.size()); i += 2) { |
---|
2828 | int sb = subblossoms[(ib + i) % subblossoms.size()]; |
---|
2829 | int tb = subblossoms[(ib + i + 1) % subblossoms.size()]; |
---|
2830 | |
---|
2831 | Arc m = (*_blossom_data)[tb].next; |
---|
2832 | extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m)); |
---|
2833 | extractBlossom(tb, _graph.source(m), m); |
---|
2834 | } |
---|
2835 | extractBlossom(subblossoms[ib], base, matching); |
---|
2836 | |
---|
2837 | int en = _blossom_node_list.size(); |
---|
2838 | |
---|
2839 | _blossom_potential.push_back(BlossomVariable(bn, en, pot)); |
---|
2840 | } |
---|
2841 | } |
---|
2842 | |
---|
2843 | void extractMatching() { |
---|
2844 | std::vector<int> blossoms; |
---|
2845 | for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) { |
---|
2846 | blossoms.push_back(c); |
---|
2847 | } |
---|
2848 | |
---|
2849 | for (int i = 0; i < int(blossoms.size()); ++i) { |
---|
2850 | |
---|
2851 | Value offset = (*_blossom_data)[blossoms[i]].offset; |
---|
2852 | (*_blossom_data)[blossoms[i]].pot += 2 * offset; |
---|
2853 | for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]); |
---|
2854 | n != INVALID; ++n) { |
---|
2855 | (*_node_data)[(*_node_index)[n]].pot -= offset; |
---|
2856 | } |
---|
2857 | |
---|
2858 | Arc matching = (*_blossom_data)[blossoms[i]].next; |
---|
2859 | Node base = _graph.source(matching); |
---|
2860 | extractBlossom(blossoms[i], base, matching); |
---|
2861 | } |
---|
2862 | } |
---|
2863 | |
---|
2864 | public: |
---|
2865 | |
---|
2866 | /// \brief Constructor |
---|
2867 | /// |
---|
2868 | /// Constructor. |
---|
2869 | MaxWeightedPerfectMatching(const Graph& graph, const WeightMap& weight) |
---|
2870 | : _graph(graph), _weight(weight), _matching(0), |
---|
2871 | _node_potential(0), _blossom_potential(), _blossom_node_list(), |
---|
2872 | _node_num(0), _blossom_num(0), |
---|
2873 | |
---|
2874 | _blossom_index(0), _blossom_set(0), _blossom_data(0), |
---|
2875 | _node_index(0), _node_heap_index(0), _node_data(0), |
---|
2876 | _tree_set_index(0), _tree_set(0), |
---|
2877 | |
---|
2878 | _delta2_index(0), _delta2(0), |
---|
2879 | _delta3_index(0), _delta3(0), |
---|
2880 | _delta4_index(0), _delta4(0), |
---|
2881 | |
---|
2882 | _delta_sum() {} |
---|
2883 | |
---|
2884 | ~MaxWeightedPerfectMatching() { |
---|
2885 | destroyStructures(); |
---|
2886 | } |
---|
2887 | |
---|
2888 | /// \name Execution Control |
---|
2889 | /// The simplest way to execute the algorithm is to use the |
---|
2890 | /// \ref run() member function. |
---|
2891 | |
---|
2892 | ///@{ |
---|
2893 | |
---|
2894 | /// \brief Initialize the algorithm |
---|
2895 | /// |
---|
2896 | /// This function initializes the algorithm. |
---|
2897 | void init() { |
---|
2898 | createStructures(); |
---|
2899 | |
---|
2900 | for (ArcIt e(_graph); e != INVALID; ++e) { |
---|
2901 | (*_node_heap_index)[e] = BinHeap<Value, IntArcMap>::PRE_HEAP; |
---|
2902 | } |
---|
2903 | for (EdgeIt e(_graph); e != INVALID; ++e) { |
---|
2904 | (*_delta3_index)[e] = _delta3->PRE_HEAP; |
---|
2905 | } |
---|
2906 | for (int i = 0; i < _blossom_num; ++i) { |
---|
2907 | (*_delta2_index)[i] = _delta2->PRE_HEAP; |
---|
2908 | (*_delta4_index)[i] = _delta4->PRE_HEAP; |
---|
2909 | } |
---|
2910 | |
---|
2911 | int index = 0; |
---|
2912 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
2913 | Value max = - std::numeric_limits<Value>::max(); |
---|
2914 | for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
---|
2915 | if (_graph.target(e) == n) continue; |
---|
2916 | if ((dualScale * _weight[e]) / 2 > max) { |
---|
2917 | max = (dualScale * _weight[e]) / 2; |
---|
2918 | } |
---|
2919 | } |
---|
2920 | (*_node_index)[n] = index; |
---|
2921 | (*_node_data)[index].pot = max; |
---|
2922 | int blossom = |
---|
2923 | _blossom_set->insert(n, std::numeric_limits<Value>::max()); |
---|
2924 | |
---|
2925 | _tree_set->insert(blossom); |
---|
2926 | |
---|
2927 | (*_blossom_data)[blossom].status = EVEN; |
---|
2928 | (*_blossom_data)[blossom].pred = INVALID; |
---|
2929 | (*_blossom_data)[blossom].next = INVALID; |
---|
2930 | (*_blossom_data)[blossom].pot = 0; |
---|
2931 | (*_blossom_data)[blossom].offset = 0; |
---|
2932 | ++index; |
---|
2933 | } |
---|
2934 | for (EdgeIt e(_graph); e != INVALID; ++e) { |
---|
2935 | int si = (*_node_index)[_graph.u(e)]; |
---|
2936 | int ti = (*_node_index)[_graph.v(e)]; |
---|
2937 | if (_graph.u(e) != _graph.v(e)) { |
---|
2938 | _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot - |
---|
2939 | dualScale * _weight[e]) / 2); |
---|
2940 | } |
---|
2941 | } |
---|
2942 | } |
---|
2943 | |
---|
2944 | /// \brief Start the algorithm |
---|
2945 | /// |
---|
2946 | /// This function starts the algorithm. |
---|
2947 | /// |
---|
2948 | /// \pre \ref init() must be called before using this function. |
---|
2949 | bool start() { |
---|
2950 | enum OpType { |
---|
2951 | D2, D3, D4 |
---|
2952 | }; |
---|
2953 | |
---|
2954 | int unmatched = _node_num; |
---|
2955 | while (unmatched > 0) { |
---|
2956 | Value d2 = !_delta2->empty() ? |
---|
2957 | _delta2->prio() : std::numeric_limits<Value>::max(); |
---|
2958 | |
---|
2959 | Value d3 = !_delta3->empty() ? |
---|
2960 | _delta3->prio() : std::numeric_limits<Value>::max(); |
---|
2961 | |
---|
2962 | Value d4 = !_delta4->empty() ? |
---|
2963 | _delta4->prio() : std::numeric_limits<Value>::max(); |
---|
2964 | |
---|
2965 | _delta_sum = d2; OpType ot = D2; |
---|
2966 | if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; } |
---|
2967 | if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; } |
---|
2968 | |
---|
2969 | if (_delta_sum == std::numeric_limits<Value>::max()) { |
---|
2970 | return false; |
---|
2971 | } |
---|
2972 | |
---|
2973 | switch (ot) { |
---|
2974 | case D2: |
---|
2975 | { |
---|
2976 | int blossom = _delta2->top(); |
---|
2977 | Node n = _blossom_set->classTop(blossom); |
---|
2978 | Arc e = (*_node_data)[(*_node_index)[n]].heap.top(); |
---|
2979 | extendOnArc(e); |
---|
2980 | } |
---|
2981 | break; |
---|
2982 | case D3: |
---|
2983 | { |
---|
2984 | Edge e = _delta3->top(); |
---|
2985 | |
---|
2986 | int left_blossom = _blossom_set->find(_graph.u(e)); |
---|
2987 | int right_blossom = _blossom_set->find(_graph.v(e)); |
---|
2988 | |
---|
2989 | if (left_blossom == right_blossom) { |
---|
2990 | _delta3->pop(); |
---|
2991 | } else { |
---|
2992 | int left_tree = _tree_set->find(left_blossom); |
---|
2993 | int right_tree = _tree_set->find(right_blossom); |
---|
2994 | |
---|
2995 | if (left_tree == right_tree) { |
---|
2996 | shrinkOnEdge(e, left_tree); |
---|
2997 | } else { |
---|
2998 | augmentOnEdge(e); |
---|
2999 | unmatched -= 2; |
---|
3000 | } |
---|
3001 | } |
---|
3002 | } break; |
---|
3003 | case D4: |
---|
3004 | splitBlossom(_delta4->top()); |
---|
3005 | break; |
---|
3006 | } |
---|
3007 | } |
---|
3008 | extractMatching(); |
---|
3009 | return true; |
---|
3010 | } |
---|
3011 | |
---|
3012 | /// \brief Run the algorithm. |
---|
3013 | /// |
---|
3014 | /// This method runs the \c %MaxWeightedPerfectMatching algorithm. |
---|
3015 | /// |
---|
3016 | /// \note mwpm.run() is just a shortcut of the following code. |
---|
3017 | /// \code |
---|
3018 | /// mwpm.init(); |
---|
3019 | /// mwpm.start(); |
---|
3020 | /// \endcode |
---|
3021 | bool run() { |
---|
3022 | init(); |
---|
3023 | return start(); |
---|
3024 | } |
---|
3025 | |
---|
3026 | /// @} |
---|
3027 | |
---|
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. |
---|
3033 | |
---|
3034 | /// @{ |
---|
3035 | |
---|
3036 | /// \brief Return the weight of the matching. |
---|
3037 | /// |
---|
3038 | /// This function returns the weight of the found matching. |
---|
3039 | /// |
---|
3040 | /// \pre Either run() or start() must be called before using this function. |
---|
3041 | Value matchingValue() const { |
---|
3042 | Value sum = 0; |
---|
3043 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
3044 | if ((*_matching)[n] != INVALID) { |
---|
3045 | sum += _weight[(*_matching)[n]]; |
---|
3046 | } |
---|
3047 | } |
---|
3048 | return sum /= 2; |
---|
3049 | } |
---|
3050 | |
---|
3051 | /// \brief Return \c true if the given edge is in the matching. |
---|
3052 | /// |
---|
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. |
---|
3057 | bool matching(const Edge& edge) const { |
---|
3058 | return static_cast<const Edge&>((*_matching)[_graph.u(edge)]) == edge; |
---|
3059 | } |
---|
3060 | |
---|
3061 | /// \brief Return the matching arc (or edge) incident to the given node. |
---|
3062 | /// |
---|
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. |
---|
3068 | Arc matching(const Node& node) const { |
---|
3069 | return (*_matching)[node]; |
---|
3070 | } |
---|
3071 | |
---|
3072 | /// \brief Return the mate of the given node. |
---|
3073 | /// |
---|
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. |
---|
3078 | Node mate(const Node& node) const { |
---|
3079 | return _graph.target((*_matching)[node]); |
---|
3080 | } |
---|
3081 | |
---|
3082 | /// @} |
---|
3083 | |
---|
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. |
---|
3088 | |
---|
3089 | /// @{ |
---|
3090 | |
---|
3091 | /// \brief Return the value of the dual solution. |
---|
3092 | /// |
---|
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. |
---|
3098 | Value dualValue() const { |
---|
3099 | Value sum = 0; |
---|
3100 | for (NodeIt n(_graph); n != INVALID; ++n) { |
---|
3101 | sum += nodeValue(n); |
---|
3102 | } |
---|
3103 | for (int i = 0; i < blossomNum(); ++i) { |
---|
3104 | sum += blossomValue(i) * (blossomSize(i) / 2); |
---|
3105 | } |
---|
3106 | return sum; |
---|
3107 | } |
---|
3108 | |
---|
3109 | /// \brief Return the dual value (potential) of the given node. |
---|
3110 | /// |
---|
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. |
---|
3114 | Value nodeValue(const Node& n) const { |
---|
3115 | return (*_node_potential)[n]; |
---|
3116 | } |
---|
3117 | |
---|
3118 | /// \brief Return the number of the blossoms in the basis. |
---|
3119 | /// |
---|
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. |
---|
3123 | /// \see BlossomIt |
---|
3124 | int blossomNum() const { |
---|
3125 | return _blossom_potential.size(); |
---|
3126 | } |
---|
3127 | |
---|
3128 | /// \brief Return the number of the nodes in the given blossom. |
---|
3129 | /// |
---|
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 |
---|
3134 | int blossomSize(int k) const { |
---|
3135 | return _blossom_potential[k].end - _blossom_potential[k].begin; |
---|
3136 | } |
---|
3137 | |
---|
3138 | /// \brief Return the dual value (ptential) of the given blossom. |
---|
3139 | /// |
---|
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. |
---|
3143 | Value blossomValue(int k) const { |
---|
3144 | return _blossom_potential[k].value; |
---|
3145 | } |
---|
3146 | |
---|
3147 | /// \brief Iterator for obtaining the nodes of a blossom. |
---|
3148 | /// |
---|
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. |
---|
3153 | class BlossomIt { |
---|
3154 | public: |
---|
3155 | |
---|
3156 | /// \brief Constructor. |
---|
3157 | /// |
---|
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. |
---|
3163 | BlossomIt(const MaxWeightedPerfectMatching& algorithm, int variable) |
---|
3164 | : _algorithm(&algorithm) |
---|
3165 | { |
---|
3166 | _index = _algorithm->_blossom_potential[variable].begin; |
---|
3167 | _last = _algorithm->_blossom_potential[variable].end; |
---|
3168 | } |
---|
3169 | |
---|
3170 | /// \brief Conversion to \c Node. |
---|
3171 | /// |
---|
3172 | /// Conversion to \c Node. |
---|
3173 | operator Node() const { |
---|
3174 | return _algorithm->_blossom_node_list[_index]; |
---|
3175 | } |
---|
3176 | |
---|
3177 | /// \brief Increment operator. |
---|
3178 | /// |
---|
3179 | /// Increment operator. |
---|
3180 | BlossomIt& operator++() { |
---|
3181 | ++_index; |
---|
3182 | return *this; |
---|
3183 | } |
---|
3184 | |
---|
3185 | /// \brief Validity checking |
---|
3186 | /// |
---|
3187 | /// This function checks whether the iterator is invalid. |
---|
3188 | bool operator==(Invalid) const { return _index == _last; } |
---|
3189 | |
---|
3190 | /// \brief Validity checking |
---|
3191 | /// |
---|
3192 | /// This function checks whether the iterator is valid. |
---|
3193 | bool operator!=(Invalid) const { return _index != _last; } |
---|
3194 | |
---|
3195 | private: |
---|
3196 | const MaxWeightedPerfectMatching* _algorithm; |
---|
3197 | int _last; |
---|
3198 | int _index; |
---|
3199 | }; |
---|
3200 | |
---|
3201 | /// @} |
---|
3202 | |
---|
3203 | }; |
---|
3204 | |
---|
3205 | } //END OF NAMESPACE LEMON |
---|
3206 | |
---|
3207 | #endif //LEMON_MAX_MATCHING_H |
---|