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 Edmonds' alternating forest maximum matching algorithm. |
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41 /// |
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42 /// This class implements Edmonds' alternating forest matching |
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43 /// algorithm. The algorithm can be started from an arbitrary initial |
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44 /// matching (the default is the empty one) |
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45 /// |
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46 /// The dual solution of the problem is a map of the nodes to |
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47 /// MaxMatching::Status, having values \c EVEN/D, \c ODD/A and \c |
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48 /// MATCHED/C showing the Gallai-Edmonds decomposition of the |
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49 /// graph. The nodes in \c EVEN/D induce a graph with |
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50 /// factor-critical components, the nodes in \c ODD/A form the |
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51 /// barrier, and the nodes in \c MATCHED/C induce a graph having a |
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52 /// perfect matching. The number of the factor-critical components |
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53 /// minus the number of barrier nodes is a lower bound on the |
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54 /// unmatched nodes, and the matching is optimal if and only if this bound is |
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55 /// tight. This decomposition can be attained by calling \c |
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56 /// decomposition() after running the algorithm. |
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57 /// |
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58 /// \param _Graph The graph type the algorithm runs on. |
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59 template <typename _Graph> |
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60 class MaxMatching { |
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61 public: |
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62 |
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63 typedef _Graph Graph; |
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64 typedef typename Graph::template NodeMap<typename Graph::Arc> |
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65 MatchingMap; |
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66 |
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67 ///\brief Indicates the Gallai-Edmonds decomposition of the graph. |
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68 /// |
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69 ///Indicates the Gallai-Edmonds decomposition of the graph. The |
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70 ///nodes with Status \c EVEN/D induce a graph with factor-critical |
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71 ///components, the nodes in \c ODD/A form the canonical barrier, |
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72 ///and the nodes in \c MATCHED/C induce a graph having a perfect |
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73 ///matching. |
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74 enum Status { |
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75 EVEN = 1, D = 1, MATCHED = 0, C = 0, ODD = -1, A = -1, UNMATCHED = -2 |
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76 }; |
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77 |
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78 typedef typename Graph::template NodeMap<Status> StatusMap; |
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79 |
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80 private: |
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81 |
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82 TEMPLATE_GRAPH_TYPEDEFS(Graph); |
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83 |
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84 typedef UnionFindEnum<IntNodeMap> BlossomSet; |
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85 typedef ExtendFindEnum<IntNodeMap> TreeSet; |
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86 typedef RangeMap<Node> NodeIntMap; |
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87 typedef MatchingMap EarMap; |
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88 typedef std::vector<Node> NodeQueue; |
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89 |
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90 const Graph& _graph; |
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91 MatchingMap* _matching; |
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92 StatusMap* _status; |
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93 |
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94 EarMap* _ear; |
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95 |
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96 IntNodeMap* _blossom_set_index; |
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97 BlossomSet* _blossom_set; |
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98 NodeIntMap* _blossom_rep; |
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99 |
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100 IntNodeMap* _tree_set_index; |
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101 TreeSet* _tree_set; |
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102 |
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103 NodeQueue _node_queue; |
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104 int _process, _postpone, _last; |
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105 |
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106 int _node_num; |
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107 |
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108 private: |
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109 |
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110 void createStructures() { |
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111 _node_num = countNodes(_graph); |
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112 if (!_matching) { |
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113 _matching = new MatchingMap(_graph); |
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114 } |
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115 if (!_status) { |
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116 _status = new StatusMap(_graph); |
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117 } |
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118 if (!_ear) { |
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119 _ear = new EarMap(_graph); |
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120 } |
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121 if (!_blossom_set) { |
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122 _blossom_set_index = new IntNodeMap(_graph); |
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123 _blossom_set = new BlossomSet(*_blossom_set_index); |
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124 } |
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125 if (!_blossom_rep) { |
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126 _blossom_rep = new NodeIntMap(_node_num); |
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127 } |
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128 if (!_tree_set) { |
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129 _tree_set_index = new IntNodeMap(_graph); |
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130 _tree_set = new TreeSet(*_tree_set_index); |
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131 } |
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132 _node_queue.resize(_node_num); |
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133 } |
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134 |
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135 void destroyStructures() { |
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136 if (_matching) { |
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137 delete _matching; |
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138 } |
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139 if (_status) { |
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140 delete _status; |
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141 } |
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142 if (_ear) { |
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143 delete _ear; |
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144 } |
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145 if (_blossom_set) { |
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146 delete _blossom_set; |
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147 delete _blossom_set_index; |
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148 } |
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149 if (_blossom_rep) { |
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150 delete _blossom_rep; |
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151 } |
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152 if (_tree_set) { |
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153 delete _tree_set_index; |
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154 delete _tree_set; |
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155 } |
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156 } |
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157 |
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158 void processDense(const Node& n) { |
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159 _process = _postpone = _last = 0; |
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160 _node_queue[_last++] = n; |
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161 |
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162 while (_process != _last) { |
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163 Node u = _node_queue[_process++]; |
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164 for (OutArcIt a(_graph, u); a != INVALID; ++a) { |
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165 Node v = _graph.target(a); |
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166 if ((*_status)[v] == MATCHED) { |
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167 extendOnArc(a); |
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168 } else if ((*_status)[v] == UNMATCHED) { |
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169 augmentOnArc(a); |
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170 return; |
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171 } |
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172 } |
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173 } |
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174 |
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175 while (_postpone != _last) { |
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176 Node u = _node_queue[_postpone++]; |
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177 |
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178 for (OutArcIt a(_graph, u); a != INVALID ; ++a) { |
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179 Node v = _graph.target(a); |
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180 |
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181 if ((*_status)[v] == EVEN) { |
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182 if (_blossom_set->find(u) != _blossom_set->find(v)) { |
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183 shrinkOnEdge(a); |
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184 } |
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185 } |
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186 |
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187 while (_process != _last) { |
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188 Node w = _node_queue[_process++]; |
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189 for (OutArcIt b(_graph, w); b != INVALID; ++b) { |
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190 Node x = _graph.target(b); |
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191 if ((*_status)[x] == MATCHED) { |
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192 extendOnArc(b); |
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193 } else if ((*_status)[x] == UNMATCHED) { |
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194 augmentOnArc(b); |
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195 return; |
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196 } |
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197 } |
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198 } |
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199 } |
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200 } |
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201 } |
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202 |
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203 void processSparse(const Node& n) { |
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204 _process = _last = 0; |
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205 _node_queue[_last++] = n; |
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206 while (_process != _last) { |
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207 Node u = _node_queue[_process++]; |
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208 for (OutArcIt a(_graph, u); a != INVALID; ++a) { |
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209 Node v = _graph.target(a); |
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210 |
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211 if ((*_status)[v] == EVEN) { |
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212 if (_blossom_set->find(u) != _blossom_set->find(v)) { |
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213 shrinkOnEdge(a); |
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214 } |
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215 } else if ((*_status)[v] == MATCHED) { |
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216 extendOnArc(a); |
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217 } else if ((*_status)[v] == UNMATCHED) { |
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218 augmentOnArc(a); |
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219 return; |
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220 } |
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221 } |
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222 } |
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223 } |
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224 |
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225 void shrinkOnEdge(const Edge& e) { |
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226 Node nca = INVALID; |
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227 |
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228 { |
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229 std::set<Node> left_set, right_set; |
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230 |
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231 Node left = (*_blossom_rep)[_blossom_set->find(_graph.u(e))]; |
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232 left_set.insert(left); |
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233 |
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234 Node right = (*_blossom_rep)[_blossom_set->find(_graph.v(e))]; |
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235 right_set.insert(right); |
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236 |
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237 while (true) { |
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238 if ((*_matching)[left] == INVALID) break; |
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239 left = _graph.target((*_matching)[left]); |
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240 left = (*_blossom_rep)[_blossom_set-> |
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241 find(_graph.target((*_ear)[left]))]; |
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242 if (right_set.find(left) != right_set.end()) { |
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243 nca = left; |
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244 break; |
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245 } |
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246 left_set.insert(left); |
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247 |
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248 if ((*_matching)[right] == INVALID) break; |
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249 right = _graph.target((*_matching)[right]); |
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250 right = (*_blossom_rep)[_blossom_set-> |
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251 find(_graph.target((*_ear)[right]))]; |
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252 if (left_set.find(right) != left_set.end()) { |
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253 nca = right; |
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254 break; |
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255 } |
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256 right_set.insert(right); |
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257 } |
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258 |
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259 if (nca == INVALID) { |
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260 if ((*_matching)[left] == INVALID) { |
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261 nca = right; |
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262 while (left_set.find(nca) == left_set.end()) { |
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263 nca = _graph.target((*_matching)[nca]); |
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264 nca =(*_blossom_rep)[_blossom_set-> |
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265 find(_graph.target((*_ear)[nca]))]; |
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266 } |
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267 } else { |
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268 nca = left; |
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269 while (right_set.find(nca) == right_set.end()) { |
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270 nca = _graph.target((*_matching)[nca]); |
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271 nca = (*_blossom_rep)[_blossom_set-> |
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272 find(_graph.target((*_ear)[nca]))]; |
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273 } |
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274 } |
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275 } |
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276 } |
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277 |
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278 { |
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279 |
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280 Node node = _graph.u(e); |
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281 Arc arc = _graph.direct(e, true); |
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282 Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
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283 |
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284 while (base != nca) { |
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285 _ear->set(node, arc); |
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286 |
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287 Node n = node; |
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288 while (n != base) { |
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289 n = _graph.target((*_matching)[n]); |
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290 Arc a = (*_ear)[n]; |
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291 n = _graph.target(a); |
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292 _ear->set(n, _graph.oppositeArc(a)); |
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293 } |
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294 node = _graph.target((*_matching)[base]); |
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295 _tree_set->erase(base); |
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296 _tree_set->erase(node); |
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297 _blossom_set->insert(node, _blossom_set->find(base)); |
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298 _status->set(node, EVEN); |
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299 _node_queue[_last++] = node; |
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300 arc = _graph.oppositeArc((*_ear)[node]); |
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301 node = _graph.target((*_ear)[node]); |
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302 base = (*_blossom_rep)[_blossom_set->find(node)]; |
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303 _blossom_set->join(_graph.target(arc), base); |
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304 } |
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305 } |
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306 |
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307 _blossom_rep->set(_blossom_set->find(nca), nca); |
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308 |
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309 { |
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310 |
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311 Node node = _graph.v(e); |
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312 Arc arc = _graph.direct(e, false); |
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313 Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
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314 |
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315 while (base != nca) { |
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316 _ear->set(node, arc); |
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317 |
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318 Node n = node; |
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319 while (n != base) { |
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320 n = _graph.target((*_matching)[n]); |
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321 Arc a = (*_ear)[n]; |
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322 n = _graph.target(a); |
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323 _ear->set(n, _graph.oppositeArc(a)); |
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324 } |
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325 node = _graph.target((*_matching)[base]); |
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326 _tree_set->erase(base); |
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327 _tree_set->erase(node); |
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328 _blossom_set->insert(node, _blossom_set->find(base)); |
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329 _status->set(node, EVEN); |
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330 _node_queue[_last++] = node; |
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331 arc = _graph.oppositeArc((*_ear)[node]); |
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332 node = _graph.target((*_ear)[node]); |
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333 base = (*_blossom_rep)[_blossom_set->find(node)]; |
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334 _blossom_set->join(_graph.target(arc), base); |
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335 } |
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336 } |
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337 |
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338 _blossom_rep->set(_blossom_set->find(nca), nca); |
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339 } |
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340 |
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341 |
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342 |
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343 void extendOnArc(const Arc& a) { |
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344 Node base = _graph.source(a); |
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345 Node odd = _graph.target(a); |
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346 |
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347 _ear->set(odd, _graph.oppositeArc(a)); |
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348 Node even = _graph.target((*_matching)[odd]); |
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349 _blossom_rep->set(_blossom_set->insert(even), even); |
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350 _status->set(odd, ODD); |
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351 _status->set(even, EVEN); |
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352 int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(base)]); |
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353 _tree_set->insert(odd, tree); |
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354 _tree_set->insert(even, tree); |
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355 _node_queue[_last++] = even; |
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356 |
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357 } |
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358 |
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359 void augmentOnArc(const Arc& a) { |
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360 Node even = _graph.source(a); |
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361 Node odd = _graph.target(a); |
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362 |
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363 int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(even)]); |
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364 |
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365 _matching->set(odd, _graph.oppositeArc(a)); |
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366 _status->set(odd, MATCHED); |
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367 |
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368 Arc arc = (*_matching)[even]; |
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369 _matching->set(even, a); |
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370 |
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371 while (arc != INVALID) { |
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372 odd = _graph.target(arc); |
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373 arc = (*_ear)[odd]; |
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374 even = _graph.target(arc); |
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375 _matching->set(odd, arc); |
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376 arc = (*_matching)[even]; |
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377 _matching->set(even, _graph.oppositeArc((*_matching)[odd])); |
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378 } |
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379 |
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380 for (typename TreeSet::ItemIt it(*_tree_set, tree); |
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381 it != INVALID; ++it) { |
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382 if ((*_status)[it] == ODD) { |
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383 _status->set(it, MATCHED); |
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384 } else { |
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385 int blossom = _blossom_set->find(it); |
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386 for (typename BlossomSet::ItemIt jt(*_blossom_set, blossom); |
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387 jt != INVALID; ++jt) { |
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388 _status->set(jt, MATCHED); |
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389 } |
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390 _blossom_set->eraseClass(blossom); |
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391 } |
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392 } |
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393 _tree_set->eraseClass(tree); |
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394 |
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395 } |
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396 |
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397 public: |
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398 |
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399 /// \brief Constructor |
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400 /// |
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401 /// Constructor. |
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402 MaxMatching(const Graph& graph) |
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403 : _graph(graph), _matching(0), _status(0), _ear(0), |
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404 _blossom_set_index(0), _blossom_set(0), _blossom_rep(0), |
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405 _tree_set_index(0), _tree_set(0) {} |
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406 |
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407 ~MaxMatching() { |
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408 destroyStructures(); |
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409 } |
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410 |
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411 /// \name Execution control |
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412 /// The simplest way to execute the algorithm is to use the |
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413 /// \c run() member function. |
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414 /// \n |
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415 |
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416 /// If you need better control on the execution, you must call |
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417 /// \ref init(), \ref greedyInit() or \ref matchingInit() |
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418 /// functions first, then you can start the algorithm with the \ref |
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419 /// startSparse() or startDense() functions. |
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420 |
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421 ///@{ |
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422 |
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423 /// \brief Sets the actual matching to the empty matching. |
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424 /// |
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425 /// Sets the actual matching to the empty matching. |
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426 /// |
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427 void init() { |
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428 createStructures(); |
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429 for(NodeIt n(_graph); n != INVALID; ++n) { |
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430 _matching->set(n, INVALID); |
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431 _status->set(n, UNMATCHED); |
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432 } |
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433 } |
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434 |
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435 ///\brief Finds an initial matching in a greedy way |
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436 /// |
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437 ///It finds an initial matching in a greedy way. |
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438 void greedyInit() { |
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439 createStructures(); |
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440 for (NodeIt n(_graph); n != INVALID; ++n) { |
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441 _matching->set(n, INVALID); |
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442 _status->set(n, UNMATCHED); |
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443 } |
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444 for (NodeIt n(_graph); n != INVALID; ++n) { |
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445 if ((*_matching)[n] == INVALID) { |
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446 for (OutArcIt a(_graph, n); a != INVALID ; ++a) { |
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447 Node v = _graph.target(a); |
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448 if ((*_matching)[v] == INVALID && v != n) { |
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449 _matching->set(n, a); |
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450 _status->set(n, MATCHED); |
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451 _matching->set(v, _graph.oppositeArc(a)); |
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452 _status->set(v, MATCHED); |
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453 break; |
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454 } |
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455 } |
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456 } |
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457 } |
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458 } |
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459 |
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460 |
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461 /// \brief Initialize the matching from a map containing. |
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462 /// |
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463 /// Initialize the matching from a \c bool valued \c Edge map. This |
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464 /// map must have the property that there are no two incident edges |
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465 /// with true value, ie. it contains a matching. |
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466 /// \return %True if the map contains a matching. |
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467 template <typename MatchingMap> |
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468 bool matchingInit(const MatchingMap& matching) { |
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469 createStructures(); |
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470 |
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471 for (NodeIt n(_graph); n != INVALID; ++n) { |
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472 _matching->set(n, INVALID); |
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473 _status->set(n, UNMATCHED); |
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474 } |
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475 for(EdgeIt e(_graph); e!=INVALID; ++e) { |
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476 if (matching[e]) { |
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477 |
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478 Node u = _graph.u(e); |
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479 if ((*_matching)[u] != INVALID) return false; |
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480 _matching->set(u, _graph.direct(e, true)); |
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481 _status->set(u, MATCHED); |
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482 |
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483 Node v = _graph.v(e); |
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484 if ((*_matching)[v] != INVALID) return false; |
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485 _matching->set(v, _graph.direct(e, false)); |
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486 _status->set(v, MATCHED); |
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487 } |
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488 } |
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489 return true; |
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490 } |
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491 |
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492 /// \brief Starts Edmonds' algorithm |
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493 /// |
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494 /// If runs the original Edmonds' algorithm. |
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495 void startSparse() { |
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496 for(NodeIt n(_graph); n != INVALID; ++n) { |
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497 if ((*_status)[n] == UNMATCHED) { |
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498 (*_blossom_rep)[_blossom_set->insert(n)] = n; |
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499 _tree_set->insert(n); |
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500 _status->set(n, EVEN); |
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501 processSparse(n); |
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502 } |
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503 } |
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504 } |
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505 |
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506 /// \brief Starts Edmonds' algorithm. |
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507 /// |
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508 /// It runs Edmonds' algorithm with a heuristic of postponing |
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509 /// shrinks, therefore resulting in a faster algorithm for dense graphs. |
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510 void startDense() { |
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511 for(NodeIt n(_graph); n != INVALID; ++n) { |
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512 if ((*_status)[n] == UNMATCHED) { |
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513 (*_blossom_rep)[_blossom_set->insert(n)] = n; |
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514 _tree_set->insert(n); |
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515 _status->set(n, EVEN); |
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516 processDense(n); |
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517 } |
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518 } |
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519 } |
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520 |
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521 |
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522 /// \brief Runs Edmonds' algorithm |
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523 /// |
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524 /// Runs Edmonds' algorithm for sparse graphs (<tt>m<2*n</tt>) |
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525 /// or Edmonds' algorithm with a heuristic of |
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526 /// postponing shrinks for dense graphs. |
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527 void run() { |
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528 if (countEdges(_graph) < 2 * countNodes(_graph)) { |
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529 greedyInit(); |
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530 startSparse(); |
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531 } else { |
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532 init(); |
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533 startDense(); |
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534 } |
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535 } |
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536 |
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537 /// @} |
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538 |
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539 /// \name Primal solution |
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540 /// Functions to get the primal solution, ie. the matching. |
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541 |
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542 /// @{ |
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543 |
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544 ///\brief Returns the size of the current matching. |
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545 /// |
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546 ///Returns the size of the current matching. After \ref |
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547 ///run() it returns the size of the maximum matching in the graph. |
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548 int matchingSize() const { |
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549 int size = 0; |
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550 for (NodeIt n(_graph); n != INVALID; ++n) { |
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551 if ((*_matching)[n] != INVALID) { |
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552 ++size; |
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553 } |
|
554 } |
|
555 return size / 2; |
|
556 } |
|
557 |
|
558 /// \brief Returns true when the edge is in the matching. |
|
559 /// |
|
560 /// Returns true when the edge is in the matching. |
|
561 bool matching(const Edge& edge) const { |
|
562 return edge == (*_matching)[_graph.u(edge)]; |
|
563 } |
|
564 |
|
565 /// \brief Returns the matching edge incident to the given node. |
|
566 /// |
|
567 /// Returns the matching edge of a \c node in the actual matching or |
|
568 /// INVALID if the \c node is not covered by the actual matching. |
|
569 Arc matching(const Node& n) const { |
|
570 return (*_matching)[n]; |
|
571 } |
|
572 |
|
573 ///\brief Returns the mate of a node in the actual matching. |
|
574 /// |
|
575 ///Returns the mate of a \c node in the actual matching or |
|
576 ///INVALID if the \c node is not covered by the actual matching. |
|
577 Node mate(const Node& n) const { |
|
578 return (*_matching)[n] != INVALID ? |
|
579 _graph.target((*_matching)[n]) : INVALID; |
|
580 } |
|
581 |
|
582 /// @} |
|
583 |
|
584 /// \name Dual solution |
|
585 /// Functions to get the dual solution, ie. the decomposition. |
|
586 |
|
587 /// @{ |
|
588 |
|
589 /// \brief Returns the class of the node in the Edmonds-Gallai |
|
590 /// decomposition. |
|
591 /// |
|
592 /// Returns the class of the node in the Edmonds-Gallai |
|
593 /// decomposition. |
|
594 Status decomposition(const Node& n) const { |
|
595 return (*_status)[n]; |
|
596 } |
|
597 |
|
598 /// \brief Returns true when the node is in the barrier. |
|
599 /// |
|
600 /// Returns true when the node is in the barrier. |
|
601 bool barrier(const Node& n) const { |
|
602 return (*_status)[n] == ODD; |
|
603 } |
|
604 |
|
605 /// @} |
|
606 |
|
607 }; |
|
608 |
|
609 /// \ingroup matching |
|
610 /// |
|
611 /// \brief Weighted matching in general graphs |
|
612 /// |
|
613 /// This class provides an efficient implementation of Edmond's |
|
614 /// maximum weighted matching algorithm. The implementation is based |
|
615 /// on extensive use of priority queues and provides |
|
616 /// \f$O(nm\log(n))\f$ time complexity. |
|
617 /// |
|
618 /// The maximum weighted matching problem is to find undirected |
|
619 /// edges in the graph with maximum overall weight and no two of |
|
620 /// them shares their ends. The problem can be formulated with the |
|
621 /// following linear program. |
|
622 /// \f[ \sum_{e \in \delta(u)}x_e \le 1 \quad \forall u\in V\f] |
|
623 /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2} |
|
624 \quad \forall B\in\mathcal{O}\f] */ |
|
625 /// \f[x_e \ge 0\quad \forall e\in E\f] |
|
626 /// \f[\max \sum_{e\in E}x_ew_e\f] |
|
627 /// where \f$\delta(X)\f$ is the set of edges incident to a node in |
|
628 /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in |
|
629 /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality |
|
630 /// subsets of the nodes. |
|
631 /// |
|
632 /// The algorithm calculates an optimal matching and a proof of the |
|
633 /// optimality. The solution of the dual problem can be used to check |
|
634 /// the result of the algorithm. The dual linear problem is the |
|
635 /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)} |
|
636 z_B \ge w_{uv} \quad \forall uv\in E\f] */ |
|
637 /// \f[y_u \ge 0 \quad \forall u \in V\f] |
|
638 /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f] |
|
639 /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}} |
|
640 \frac{\vert B \vert - 1}{2}z_B\f] */ |
|
641 /// |
|
642 /// The algorithm can be executed with \c run() or the \c init() and |
|
643 /// then the \c start() member functions. After it the matching can |
|
644 /// be asked with \c matching() or mate() functions. The dual |
|
645 /// solution can be get with \c nodeValue(), \c blossomNum() and \c |
|
646 /// blossomValue() members and \ref MaxWeightedMatching::BlossomIt |
|
647 /// "BlossomIt" nested class, which is able to iterate on the nodes |
|
648 /// of a blossom. If the value type is integral then the dual |
|
649 /// solution is multiplied by \ref MaxWeightedMatching::dualScale "4". |
|
650 template <typename _Graph, |
|
651 typename _WeightMap = typename _Graph::template EdgeMap<int> > |
|
652 class MaxWeightedMatching { |
|
653 public: |
|
654 |
|
655 typedef _Graph Graph; |
|
656 typedef _WeightMap WeightMap; |
|
657 typedef typename WeightMap::Value Value; |
|
658 |
|
659 /// \brief Scaling factor for dual solution |
|
660 /// |
|
661 /// Scaling factor for dual solution, it is equal to 4 or 1 |
|
662 /// according to the value type. |
|
663 static const int dualScale = |
|
664 std::numeric_limits<Value>::is_integer ? 4 : 1; |
|
665 |
|
666 typedef typename Graph::template NodeMap<typename Graph::Arc> |
|
667 MatchingMap; |
|
668 |
|
669 private: |
|
670 |
|
671 TEMPLATE_GRAPH_TYPEDEFS(Graph); |
|
672 |
|
673 typedef typename Graph::template NodeMap<Value> NodePotential; |
|
674 typedef std::vector<Node> BlossomNodeList; |
|
675 |
|
676 struct BlossomVariable { |
|
677 int begin, end; |
|
678 Value value; |
|
679 |
|
680 BlossomVariable(int _begin, int _end, Value _value) |
|
681 : begin(_begin), end(_end), value(_value) {} |
|
682 |
|
683 }; |
|
684 |
|
685 typedef std::vector<BlossomVariable> BlossomPotential; |
|
686 |
|
687 const Graph& _graph; |
|
688 const WeightMap& _weight; |
|
689 |
|
690 MatchingMap* _matching; |
|
691 |
|
692 NodePotential* _node_potential; |
|
693 |
|
694 BlossomPotential _blossom_potential; |
|
695 BlossomNodeList _blossom_node_list; |
|
696 |
|
697 int _node_num; |
|
698 int _blossom_num; |
|
699 |
|
700 typedef RangeMap<int> IntIntMap; |
|
701 |
|
702 enum Status { |
|
703 EVEN = -1, MATCHED = 0, ODD = 1, UNMATCHED = -2 |
|
704 }; |
|
705 |
|
706 typedef HeapUnionFind<Value, IntNodeMap> BlossomSet; |
|
707 struct BlossomData { |
|
708 int tree; |
|
709 Status status; |
|
710 Arc pred, next; |
|
711 Value pot, offset; |
|
712 Node base; |
|
713 }; |
|
714 |
|
715 IntNodeMap *_blossom_index; |
|
716 BlossomSet *_blossom_set; |
|
717 RangeMap<BlossomData>* _blossom_data; |
|
718 |
|
719 IntNodeMap *_node_index; |
|
720 IntArcMap *_node_heap_index; |
|
721 |
|
722 struct NodeData { |
|
723 |
|
724 NodeData(IntArcMap& node_heap_index) |
|
725 : heap(node_heap_index) {} |
|
726 |
|
727 int blossom; |
|
728 Value pot; |
|
729 BinHeap<Value, IntArcMap> heap; |
|
730 std::map<int, Arc> heap_index; |
|
731 |
|
732 int tree; |
|
733 }; |
|
734 |
|
735 RangeMap<NodeData>* _node_data; |
|
736 |
|
737 typedef ExtendFindEnum<IntIntMap> TreeSet; |
|
738 |
|
739 IntIntMap *_tree_set_index; |
|
740 TreeSet *_tree_set; |
|
741 |
|
742 IntNodeMap *_delta1_index; |
|
743 BinHeap<Value, IntNodeMap> *_delta1; |
|
744 |
|
745 IntIntMap *_delta2_index; |
|
746 BinHeap<Value, IntIntMap> *_delta2; |
|
747 |
|
748 IntEdgeMap *_delta3_index; |
|
749 BinHeap<Value, IntEdgeMap> *_delta3; |
|
750 |
|
751 IntIntMap *_delta4_index; |
|
752 BinHeap<Value, IntIntMap> *_delta4; |
|
753 |
|
754 Value _delta_sum; |
|
755 |
|
756 void createStructures() { |
|
757 _node_num = countNodes(_graph); |
|
758 _blossom_num = _node_num * 3 / 2; |
|
759 |
|
760 if (!_matching) { |
|
761 _matching = new MatchingMap(_graph); |
|
762 } |
|
763 if (!_node_potential) { |
|
764 _node_potential = new NodePotential(_graph); |
|
765 } |
|
766 if (!_blossom_set) { |
|
767 _blossom_index = new IntNodeMap(_graph); |
|
768 _blossom_set = new BlossomSet(*_blossom_index); |
|
769 _blossom_data = new RangeMap<BlossomData>(_blossom_num); |
|
770 } |
|
771 |
|
772 if (!_node_index) { |
|
773 _node_index = new IntNodeMap(_graph); |
|
774 _node_heap_index = new IntArcMap(_graph); |
|
775 _node_data = new RangeMap<NodeData>(_node_num, |
|
776 NodeData(*_node_heap_index)); |
|
777 } |
|
778 |
|
779 if (!_tree_set) { |
|
780 _tree_set_index = new IntIntMap(_blossom_num); |
|
781 _tree_set = new TreeSet(*_tree_set_index); |
|
782 } |
|
783 if (!_delta1) { |
|
784 _delta1_index = new IntNodeMap(_graph); |
|
785 _delta1 = new BinHeap<Value, IntNodeMap>(*_delta1_index); |
|
786 } |
|
787 if (!_delta2) { |
|
788 _delta2_index = new IntIntMap(_blossom_num); |
|
789 _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index); |
|
790 } |
|
791 if (!_delta3) { |
|
792 _delta3_index = new IntEdgeMap(_graph); |
|
793 _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index); |
|
794 } |
|
795 if (!_delta4) { |
|
796 _delta4_index = new IntIntMap(_blossom_num); |
|
797 _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index); |
|
798 } |
|
799 } |
|
800 |
|
801 void destroyStructures() { |
|
802 _node_num = countNodes(_graph); |
|
803 _blossom_num = _node_num * 3 / 2; |
|
804 |
|
805 if (_matching) { |
|
806 delete _matching; |
|
807 } |
|
808 if (_node_potential) { |
|
809 delete _node_potential; |
|
810 } |
|
811 if (_blossom_set) { |
|
812 delete _blossom_index; |
|
813 delete _blossom_set; |
|
814 delete _blossom_data; |
|
815 } |
|
816 |
|
817 if (_node_index) { |
|
818 delete _node_index; |
|
819 delete _node_heap_index; |
|
820 delete _node_data; |
|
821 } |
|
822 |
|
823 if (_tree_set) { |
|
824 delete _tree_set_index; |
|
825 delete _tree_set; |
|
826 } |
|
827 if (_delta1) { |
|
828 delete _delta1_index; |
|
829 delete _delta1; |
|
830 } |
|
831 if (_delta2) { |
|
832 delete _delta2_index; |
|
833 delete _delta2; |
|
834 } |
|
835 if (_delta3) { |
|
836 delete _delta3_index; |
|
837 delete _delta3; |
|
838 } |
|
839 if (_delta4) { |
|
840 delete _delta4_index; |
|
841 delete _delta4; |
|
842 } |
|
843 } |
|
844 |
|
845 void matchedToEven(int blossom, int tree) { |
|
846 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
|
847 _delta2->erase(blossom); |
|
848 } |
|
849 |
|
850 if (!_blossom_set->trivial(blossom)) { |
|
851 (*_blossom_data)[blossom].pot -= |
|
852 2 * (_delta_sum - (*_blossom_data)[blossom].offset); |
|
853 } |
|
854 |
|
855 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
|
856 n != INVALID; ++n) { |
|
857 |
|
858 _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
|
859 int ni = (*_node_index)[n]; |
|
860 |
|
861 (*_node_data)[ni].heap.clear(); |
|
862 (*_node_data)[ni].heap_index.clear(); |
|
863 |
|
864 (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset; |
|
865 |
|
866 _delta1->push(n, (*_node_data)[ni].pot); |
|
867 |
|
868 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
|
869 Node v = _graph.source(e); |
|
870 int vb = _blossom_set->find(v); |
|
871 int vi = (*_node_index)[v]; |
|
872 |
|
873 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
|
874 dualScale * _weight[e]; |
|
875 |
|
876 if ((*_blossom_data)[vb].status == EVEN) { |
|
877 if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
|
878 _delta3->push(e, rw / 2); |
|
879 } |
|
880 } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
|
881 if (_delta3->state(e) != _delta3->IN_HEAP) { |
|
882 _delta3->push(e, rw); |
|
883 } |
|
884 } else { |
|
885 typename std::map<int, Arc>::iterator it = |
|
886 (*_node_data)[vi].heap_index.find(tree); |
|
887 |
|
888 if (it != (*_node_data)[vi].heap_index.end()) { |
|
889 if ((*_node_data)[vi].heap[it->second] > rw) { |
|
890 (*_node_data)[vi].heap.replace(it->second, e); |
|
891 (*_node_data)[vi].heap.decrease(e, rw); |
|
892 it->second = e; |
|
893 } |
|
894 } else { |
|
895 (*_node_data)[vi].heap.push(e, rw); |
|
896 (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
|
897 } |
|
898 |
|
899 if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
|
900 _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
|
901 |
|
902 if ((*_blossom_data)[vb].status == MATCHED) { |
|
903 if (_delta2->state(vb) != _delta2->IN_HEAP) { |
|
904 _delta2->push(vb, _blossom_set->classPrio(vb) - |
|
905 (*_blossom_data)[vb].offset); |
|
906 } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
|
907 (*_blossom_data)[vb].offset){ |
|
908 _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
|
909 (*_blossom_data)[vb].offset); |
|
910 } |
|
911 } |
|
912 } |
|
913 } |
|
914 } |
|
915 } |
|
916 (*_blossom_data)[blossom].offset = 0; |
|
917 } |
|
918 |
|
919 void matchedToOdd(int blossom) { |
|
920 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
|
921 _delta2->erase(blossom); |
|
922 } |
|
923 (*_blossom_data)[blossom].offset += _delta_sum; |
|
924 if (!_blossom_set->trivial(blossom)) { |
|
925 _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 + |
|
926 (*_blossom_data)[blossom].offset); |
|
927 } |
|
928 } |
|
929 |
|
930 void evenToMatched(int blossom, int tree) { |
|
931 if (!_blossom_set->trivial(blossom)) { |
|
932 (*_blossom_data)[blossom].pot += 2 * _delta_sum; |
|
933 } |
|
934 |
|
935 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
|
936 n != INVALID; ++n) { |
|
937 int ni = (*_node_index)[n]; |
|
938 (*_node_data)[ni].pot -= _delta_sum; |
|
939 |
|
940 _delta1->erase(n); |
|
941 |
|
942 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
|
943 Node v = _graph.source(e); |
|
944 int vb = _blossom_set->find(v); |
|
945 int vi = (*_node_index)[v]; |
|
946 |
|
947 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
|
948 dualScale * _weight[e]; |
|
949 |
|
950 if (vb == blossom) { |
|
951 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
952 _delta3->erase(e); |
|
953 } |
|
954 } else if ((*_blossom_data)[vb].status == EVEN) { |
|
955 |
|
956 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
957 _delta3->erase(e); |
|
958 } |
|
959 |
|
960 int vt = _tree_set->find(vb); |
|
961 |
|
962 if (vt != tree) { |
|
963 |
|
964 Arc r = _graph.oppositeArc(e); |
|
965 |
|
966 typename std::map<int, Arc>::iterator it = |
|
967 (*_node_data)[ni].heap_index.find(vt); |
|
968 |
|
969 if (it != (*_node_data)[ni].heap_index.end()) { |
|
970 if ((*_node_data)[ni].heap[it->second] > rw) { |
|
971 (*_node_data)[ni].heap.replace(it->second, r); |
|
972 (*_node_data)[ni].heap.decrease(r, rw); |
|
973 it->second = r; |
|
974 } |
|
975 } else { |
|
976 (*_node_data)[ni].heap.push(r, rw); |
|
977 (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
|
978 } |
|
979 |
|
980 if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
|
981 _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
|
982 |
|
983 if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
|
984 _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
|
985 (*_blossom_data)[blossom].offset); |
|
986 } else if ((*_delta2)[blossom] > |
|
987 _blossom_set->classPrio(blossom) - |
|
988 (*_blossom_data)[blossom].offset){ |
|
989 _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
|
990 (*_blossom_data)[blossom].offset); |
|
991 } |
|
992 } |
|
993 } |
|
994 |
|
995 } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
|
996 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
997 _delta3->erase(e); |
|
998 } |
|
999 } else { |
|
1000 |
|
1001 typename std::map<int, Arc>::iterator it = |
|
1002 (*_node_data)[vi].heap_index.find(tree); |
|
1003 |
|
1004 if (it != (*_node_data)[vi].heap_index.end()) { |
|
1005 (*_node_data)[vi].heap.erase(it->second); |
|
1006 (*_node_data)[vi].heap_index.erase(it); |
|
1007 if ((*_node_data)[vi].heap.empty()) { |
|
1008 _blossom_set->increase(v, std::numeric_limits<Value>::max()); |
|
1009 } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) { |
|
1010 _blossom_set->increase(v, (*_node_data)[vi].heap.prio()); |
|
1011 } |
|
1012 |
|
1013 if ((*_blossom_data)[vb].status == MATCHED) { |
|
1014 if (_blossom_set->classPrio(vb) == |
|
1015 std::numeric_limits<Value>::max()) { |
|
1016 _delta2->erase(vb); |
|
1017 } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) - |
|
1018 (*_blossom_data)[vb].offset) { |
|
1019 _delta2->increase(vb, _blossom_set->classPrio(vb) - |
|
1020 (*_blossom_data)[vb].offset); |
|
1021 } |
|
1022 } |
|
1023 } |
|
1024 } |
|
1025 } |
|
1026 } |
|
1027 } |
|
1028 |
|
1029 void oddToMatched(int blossom) { |
|
1030 (*_blossom_data)[blossom].offset -= _delta_sum; |
|
1031 |
|
1032 if (_blossom_set->classPrio(blossom) != |
|
1033 std::numeric_limits<Value>::max()) { |
|
1034 _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
|
1035 (*_blossom_data)[blossom].offset); |
|
1036 } |
|
1037 |
|
1038 if (!_blossom_set->trivial(blossom)) { |
|
1039 _delta4->erase(blossom); |
|
1040 } |
|
1041 } |
|
1042 |
|
1043 void oddToEven(int blossom, int tree) { |
|
1044 if (!_blossom_set->trivial(blossom)) { |
|
1045 _delta4->erase(blossom); |
|
1046 (*_blossom_data)[blossom].pot -= |
|
1047 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset); |
|
1048 } |
|
1049 |
|
1050 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
|
1051 n != INVALID; ++n) { |
|
1052 int ni = (*_node_index)[n]; |
|
1053 |
|
1054 _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
|
1055 |
|
1056 (*_node_data)[ni].heap.clear(); |
|
1057 (*_node_data)[ni].heap_index.clear(); |
|
1058 (*_node_data)[ni].pot += |
|
1059 2 * _delta_sum - (*_blossom_data)[blossom].offset; |
|
1060 |
|
1061 _delta1->push(n, (*_node_data)[ni].pot); |
|
1062 |
|
1063 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
|
1064 Node v = _graph.source(e); |
|
1065 int vb = _blossom_set->find(v); |
|
1066 int vi = (*_node_index)[v]; |
|
1067 |
|
1068 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
|
1069 dualScale * _weight[e]; |
|
1070 |
|
1071 if ((*_blossom_data)[vb].status == EVEN) { |
|
1072 if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
|
1073 _delta3->push(e, rw / 2); |
|
1074 } |
|
1075 } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
|
1076 if (_delta3->state(e) != _delta3->IN_HEAP) { |
|
1077 _delta3->push(e, rw); |
|
1078 } |
|
1079 } else { |
|
1080 |
|
1081 typename std::map<int, Arc>::iterator it = |
|
1082 (*_node_data)[vi].heap_index.find(tree); |
|
1083 |
|
1084 if (it != (*_node_data)[vi].heap_index.end()) { |
|
1085 if ((*_node_data)[vi].heap[it->second] > rw) { |
|
1086 (*_node_data)[vi].heap.replace(it->second, e); |
|
1087 (*_node_data)[vi].heap.decrease(e, rw); |
|
1088 it->second = e; |
|
1089 } |
|
1090 } else { |
|
1091 (*_node_data)[vi].heap.push(e, rw); |
|
1092 (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
|
1093 } |
|
1094 |
|
1095 if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
|
1096 _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
|
1097 |
|
1098 if ((*_blossom_data)[vb].status == MATCHED) { |
|
1099 if (_delta2->state(vb) != _delta2->IN_HEAP) { |
|
1100 _delta2->push(vb, _blossom_set->classPrio(vb) - |
|
1101 (*_blossom_data)[vb].offset); |
|
1102 } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
|
1103 (*_blossom_data)[vb].offset) { |
|
1104 _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
|
1105 (*_blossom_data)[vb].offset); |
|
1106 } |
|
1107 } |
|
1108 } |
|
1109 } |
|
1110 } |
|
1111 } |
|
1112 (*_blossom_data)[blossom].offset = 0; |
|
1113 } |
|
1114 |
|
1115 |
|
1116 void matchedToUnmatched(int blossom) { |
|
1117 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
|
1118 _delta2->erase(blossom); |
|
1119 } |
|
1120 |
|
1121 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
|
1122 n != INVALID; ++n) { |
|
1123 int ni = (*_node_index)[n]; |
|
1124 |
|
1125 _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
|
1126 |
|
1127 (*_node_data)[ni].heap.clear(); |
|
1128 (*_node_data)[ni].heap_index.clear(); |
|
1129 |
|
1130 for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
|
1131 Node v = _graph.target(e); |
|
1132 int vb = _blossom_set->find(v); |
|
1133 int vi = (*_node_index)[v]; |
|
1134 |
|
1135 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
|
1136 dualScale * _weight[e]; |
|
1137 |
|
1138 if ((*_blossom_data)[vb].status == EVEN) { |
|
1139 if (_delta3->state(e) != _delta3->IN_HEAP) { |
|
1140 _delta3->push(e, rw); |
|
1141 } |
|
1142 } |
|
1143 } |
|
1144 } |
|
1145 } |
|
1146 |
|
1147 void unmatchedToMatched(int blossom) { |
|
1148 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
|
1149 n != INVALID; ++n) { |
|
1150 int ni = (*_node_index)[n]; |
|
1151 |
|
1152 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
|
1153 Node v = _graph.source(e); |
|
1154 int vb = _blossom_set->find(v); |
|
1155 int vi = (*_node_index)[v]; |
|
1156 |
|
1157 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
|
1158 dualScale * _weight[e]; |
|
1159 |
|
1160 if (vb == blossom) { |
|
1161 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
1162 _delta3->erase(e); |
|
1163 } |
|
1164 } else if ((*_blossom_data)[vb].status == EVEN) { |
|
1165 |
|
1166 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
1167 _delta3->erase(e); |
|
1168 } |
|
1169 |
|
1170 int vt = _tree_set->find(vb); |
|
1171 |
|
1172 Arc r = _graph.oppositeArc(e); |
|
1173 |
|
1174 typename std::map<int, Arc>::iterator it = |
|
1175 (*_node_data)[ni].heap_index.find(vt); |
|
1176 |
|
1177 if (it != (*_node_data)[ni].heap_index.end()) { |
|
1178 if ((*_node_data)[ni].heap[it->second] > rw) { |
|
1179 (*_node_data)[ni].heap.replace(it->second, r); |
|
1180 (*_node_data)[ni].heap.decrease(r, rw); |
|
1181 it->second = r; |
|
1182 } |
|
1183 } else { |
|
1184 (*_node_data)[ni].heap.push(r, rw); |
|
1185 (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
|
1186 } |
|
1187 |
|
1188 if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
|
1189 _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
|
1190 |
|
1191 if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
|
1192 _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
|
1193 (*_blossom_data)[blossom].offset); |
|
1194 } else if ((*_delta2)[blossom] > _blossom_set->classPrio(blossom)- |
|
1195 (*_blossom_data)[blossom].offset){ |
|
1196 _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
|
1197 (*_blossom_data)[blossom].offset); |
|
1198 } |
|
1199 } |
|
1200 |
|
1201 } else if ((*_blossom_data)[vb].status == UNMATCHED) { |
|
1202 if (_delta3->state(e) == _delta3->IN_HEAP) { |
|
1203 _delta3->erase(e); |
|
1204 } |
|
1205 } |
|
1206 } |
|
1207 } |
|
1208 } |
|
1209 |
|
1210 void alternatePath(int even, int tree) { |
|
1211 int odd; |
|
1212 |
|
1213 evenToMatched(even, tree); |
|
1214 (*_blossom_data)[even].status = MATCHED; |
|
1215 |
|
1216 while ((*_blossom_data)[even].pred != INVALID) { |
|
1217 odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred)); |
|
1218 (*_blossom_data)[odd].status = MATCHED; |
|
1219 oddToMatched(odd); |
|
1220 (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred; |
|
1221 |
|
1222 even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred)); |
|
1223 (*_blossom_data)[even].status = MATCHED; |
|
1224 evenToMatched(even, tree); |
|
1225 (*_blossom_data)[even].next = |
|
1226 _graph.oppositeArc((*_blossom_data)[odd].pred); |
|
1227 } |
|
1228 |
|
1229 } |
|
1230 |
|
1231 void destroyTree(int tree) { |
|
1232 for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) { |
|
1233 if ((*_blossom_data)[b].status == EVEN) { |
|
1234 (*_blossom_data)[b].status = MATCHED; |
|
1235 evenToMatched(b, tree); |
|
1236 } else if ((*_blossom_data)[b].status == ODD) { |
|
1237 (*_blossom_data)[b].status = MATCHED; |
|
1238 oddToMatched(b); |
|
1239 } |
|
1240 } |
|
1241 _tree_set->eraseClass(tree); |
|
1242 } |
|
1243 |
|
1244 |
|
1245 void unmatchNode(const Node& node) { |
|
1246 int blossom = _blossom_set->find(node); |
|
1247 int tree = _tree_set->find(blossom); |
|
1248 |
|
1249 alternatePath(blossom, tree); |
|
1250 destroyTree(tree); |
|
1251 |
|
1252 (*_blossom_data)[blossom].status = UNMATCHED; |
|
1253 (*_blossom_data)[blossom].base = node; |
|
1254 matchedToUnmatched(blossom); |
|
1255 } |
|
1256 |
|
1257 |
|
1258 void augmentOnEdge(const Edge& edge) { |
|
1259 |
|
1260 int left = _blossom_set->find(_graph.u(edge)); |
|
1261 int right = _blossom_set->find(_graph.v(edge)); |
|
1262 |
|
1263 if ((*_blossom_data)[left].status == EVEN) { |
|
1264 int left_tree = _tree_set->find(left); |
|
1265 alternatePath(left, left_tree); |
|
1266 destroyTree(left_tree); |
|
1267 } else { |
|
1268 (*_blossom_data)[left].status = MATCHED; |
|
1269 unmatchedToMatched(left); |
|
1270 } |
|
1271 |
|
1272 if ((*_blossom_data)[right].status == EVEN) { |
|
1273 int right_tree = _tree_set->find(right); |
|
1274 alternatePath(right, right_tree); |
|
1275 destroyTree(right_tree); |
|
1276 } else { |
|
1277 (*_blossom_data)[right].status = MATCHED; |
|
1278 unmatchedToMatched(right); |
|
1279 } |
|
1280 |
|
1281 (*_blossom_data)[left].next = _graph.direct(edge, true); |
|
1282 (*_blossom_data)[right].next = _graph.direct(edge, false); |
|
1283 } |
|
1284 |
|
1285 void extendOnArc(const Arc& arc) { |
|
1286 int base = _blossom_set->find(_graph.target(arc)); |
|
1287 int tree = _tree_set->find(base); |
|
1288 |
|
1289 int odd = _blossom_set->find(_graph.source(arc)); |
|
1290 _tree_set->insert(odd, tree); |
|
1291 (*_blossom_data)[odd].status = ODD; |
|
1292 matchedToOdd(odd); |
|
1293 (*_blossom_data)[odd].pred = arc; |
|
1294 |
|
1295 int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next)); |
|
1296 (*_blossom_data)[even].pred = (*_blossom_data)[even].next; |
|
1297 _tree_set->insert(even, tree); |
|
1298 (*_blossom_data)[even].status = EVEN; |
|
1299 matchedToEven(even, tree); |
|
1300 } |
|
1301 |
|
1302 void shrinkOnEdge(const Edge& edge, int tree) { |
|
1303 int nca = -1; |
|
1304 std::vector<int> left_path, right_path; |
|
1305 |
|
1306 { |
|
1307 std::set<int> left_set, right_set; |
|
1308 int left = _blossom_set->find(_graph.u(edge)); |
|
1309 left_path.push_back(left); |
|
1310 left_set.insert(left); |
|
1311 |
|
1312 int right = _blossom_set->find(_graph.v(edge)); |
|
1313 right_path.push_back(right); |
|
1314 right_set.insert(right); |
|
1315 |
|
1316 while (true) { |
|
1317 |
|
1318 if ((*_blossom_data)[left].pred == INVALID) break; |
|
1319 |
|
1320 left = |
|
1321 _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
|
1322 left_path.push_back(left); |
|
1323 left = |
|
1324 _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
|
1325 left_path.push_back(left); |
|
1326 |
|
1327 left_set.insert(left); |
|
1328 |
|
1329 if (right_set.find(left) != right_set.end()) { |
|
1330 nca = left; |
|
1331 break; |
|
1332 } |
|
1333 |
|
1334 if ((*_blossom_data)[right].pred == INVALID) break; |
|
1335 |
|
1336 right = |
|
1337 _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
|
1338 right_path.push_back(right); |
|
1339 right = |
|
1340 _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
|
1341 right_path.push_back(right); |
|
1342 |
|
1343 right_set.insert(right); |
|
1344 |
|
1345 if (left_set.find(right) != left_set.end()) { |
|
1346 nca = right; |
|
1347 break; |
|
1348 } |
|
1349 |
|
1350 } |
|
1351 |
|
1352 if (nca == -1) { |
|
1353 if ((*_blossom_data)[left].pred == INVALID) { |
|
1354 nca = right; |
|
1355 while (left_set.find(nca) == left_set.end()) { |
|
1356 nca = |
|
1357 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
1358 right_path.push_back(nca); |
|
1359 nca = |
|
1360 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
1361 right_path.push_back(nca); |
|
1362 } |
|
1363 } else { |
|
1364 nca = left; |
|
1365 while (right_set.find(nca) == right_set.end()) { |
|
1366 nca = |
|
1367 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
1368 left_path.push_back(nca); |
|
1369 nca = |
|
1370 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
1371 left_path.push_back(nca); |
|
1372 } |
|
1373 } |
|
1374 } |
|
1375 } |
|
1376 |
|
1377 std::vector<int> subblossoms; |
|
1378 Arc prev; |
|
1379 |
|
1380 prev = _graph.direct(edge, true); |
|
1381 for (int i = 0; left_path[i] != nca; i += 2) { |
|
1382 subblossoms.push_back(left_path[i]); |
|
1383 (*_blossom_data)[left_path[i]].next = prev; |
|
1384 _tree_set->erase(left_path[i]); |
|
1385 |
|
1386 subblossoms.push_back(left_path[i + 1]); |
|
1387 (*_blossom_data)[left_path[i + 1]].status = EVEN; |
|
1388 oddToEven(left_path[i + 1], tree); |
|
1389 _tree_set->erase(left_path[i + 1]); |
|
1390 prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred); |
|
1391 } |
|
1392 |
|
1393 int k = 0; |
|
1394 while (right_path[k] != nca) ++k; |
|
1395 |
|
1396 subblossoms.push_back(nca); |
|
1397 (*_blossom_data)[nca].next = prev; |
|
1398 |
|
1399 for (int i = k - 2; i >= 0; i -= 2) { |
|
1400 subblossoms.push_back(right_path[i + 1]); |
|
1401 (*_blossom_data)[right_path[i + 1]].status = EVEN; |
|
1402 oddToEven(right_path[i + 1], tree); |
|
1403 _tree_set->erase(right_path[i + 1]); |
|
1404 |
|
1405 (*_blossom_data)[right_path[i + 1]].next = |
|
1406 (*_blossom_data)[right_path[i + 1]].pred; |
|
1407 |
|
1408 subblossoms.push_back(right_path[i]); |
|
1409 _tree_set->erase(right_path[i]); |
|
1410 } |
|
1411 |
|
1412 int surface = |
|
1413 _blossom_set->join(subblossoms.begin(), subblossoms.end()); |
|
1414 |
|
1415 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
1416 if (!_blossom_set->trivial(subblossoms[i])) { |
|
1417 (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum; |
|
1418 } |
|
1419 (*_blossom_data)[subblossoms[i]].status = MATCHED; |
|
1420 } |
|
1421 |
|
1422 (*_blossom_data)[surface].pot = -2 * _delta_sum; |
|
1423 (*_blossom_data)[surface].offset = 0; |
|
1424 (*_blossom_data)[surface].status = EVEN; |
|
1425 (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred; |
|
1426 (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred; |
|
1427 |
|
1428 _tree_set->insert(surface, tree); |
|
1429 _tree_set->erase(nca); |
|
1430 } |
|
1431 |
|
1432 void splitBlossom(int blossom) { |
|
1433 Arc next = (*_blossom_data)[blossom].next; |
|
1434 Arc pred = (*_blossom_data)[blossom].pred; |
|
1435 |
|
1436 int tree = _tree_set->find(blossom); |
|
1437 |
|
1438 (*_blossom_data)[blossom].status = MATCHED; |
|
1439 oddToMatched(blossom); |
|
1440 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
|
1441 _delta2->erase(blossom); |
|
1442 } |
|
1443 |
|
1444 std::vector<int> subblossoms; |
|
1445 _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
|
1446 |
|
1447 Value offset = (*_blossom_data)[blossom].offset; |
|
1448 int b = _blossom_set->find(_graph.source(pred)); |
|
1449 int d = _blossom_set->find(_graph.source(next)); |
|
1450 |
|
1451 int ib = -1, id = -1; |
|
1452 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
1453 if (subblossoms[i] == b) ib = i; |
|
1454 if (subblossoms[i] == d) id = i; |
|
1455 |
|
1456 (*_blossom_data)[subblossoms[i]].offset = offset; |
|
1457 if (!_blossom_set->trivial(subblossoms[i])) { |
|
1458 (*_blossom_data)[subblossoms[i]].pot -= 2 * offset; |
|
1459 } |
|
1460 if (_blossom_set->classPrio(subblossoms[i]) != |
|
1461 std::numeric_limits<Value>::max()) { |
|
1462 _delta2->push(subblossoms[i], |
|
1463 _blossom_set->classPrio(subblossoms[i]) - |
|
1464 (*_blossom_data)[subblossoms[i]].offset); |
|
1465 } |
|
1466 } |
|
1467 |
|
1468 if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) { |
|
1469 for (int i = (id + 1) % subblossoms.size(); |
|
1470 i != ib; i = (i + 2) % subblossoms.size()) { |
|
1471 int sb = subblossoms[i]; |
|
1472 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
1473 (*_blossom_data)[sb].next = |
|
1474 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
1475 } |
|
1476 |
|
1477 for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) { |
|
1478 int sb = subblossoms[i]; |
|
1479 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
1480 int ub = subblossoms[(i + 2) % subblossoms.size()]; |
|
1481 |
|
1482 (*_blossom_data)[sb].status = ODD; |
|
1483 matchedToOdd(sb); |
|
1484 _tree_set->insert(sb, tree); |
|
1485 (*_blossom_data)[sb].pred = pred; |
|
1486 (*_blossom_data)[sb].next = |
|
1487 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
1488 |
|
1489 pred = (*_blossom_data)[ub].next; |
|
1490 |
|
1491 (*_blossom_data)[tb].status = EVEN; |
|
1492 matchedToEven(tb, tree); |
|
1493 _tree_set->insert(tb, tree); |
|
1494 (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next; |
|
1495 } |
|
1496 |
|
1497 (*_blossom_data)[subblossoms[id]].status = ODD; |
|
1498 matchedToOdd(subblossoms[id]); |
|
1499 _tree_set->insert(subblossoms[id], tree); |
|
1500 (*_blossom_data)[subblossoms[id]].next = next; |
|
1501 (*_blossom_data)[subblossoms[id]].pred = pred; |
|
1502 |
|
1503 } else { |
|
1504 |
|
1505 for (int i = (ib + 1) % subblossoms.size(); |
|
1506 i != id; i = (i + 2) % subblossoms.size()) { |
|
1507 int sb = subblossoms[i]; |
|
1508 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
1509 (*_blossom_data)[sb].next = |
|
1510 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
1511 } |
|
1512 |
|
1513 for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) { |
|
1514 int sb = subblossoms[i]; |
|
1515 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
1516 int ub = subblossoms[(i + 2) % subblossoms.size()]; |
|
1517 |
|
1518 (*_blossom_data)[sb].status = ODD; |
|
1519 matchedToOdd(sb); |
|
1520 _tree_set->insert(sb, tree); |
|
1521 (*_blossom_data)[sb].next = next; |
|
1522 (*_blossom_data)[sb].pred = |
|
1523 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
1524 |
|
1525 (*_blossom_data)[tb].status = EVEN; |
|
1526 matchedToEven(tb, tree); |
|
1527 _tree_set->insert(tb, tree); |
|
1528 (*_blossom_data)[tb].pred = |
|
1529 (*_blossom_data)[tb].next = |
|
1530 _graph.oppositeArc((*_blossom_data)[ub].next); |
|
1531 next = (*_blossom_data)[ub].next; |
|
1532 } |
|
1533 |
|
1534 (*_blossom_data)[subblossoms[ib]].status = ODD; |
|
1535 matchedToOdd(subblossoms[ib]); |
|
1536 _tree_set->insert(subblossoms[ib], tree); |
|
1537 (*_blossom_data)[subblossoms[ib]].next = next; |
|
1538 (*_blossom_data)[subblossoms[ib]].pred = pred; |
|
1539 } |
|
1540 _tree_set->erase(blossom); |
|
1541 } |
|
1542 |
|
1543 void extractBlossom(int blossom, const Node& base, const Arc& matching) { |
|
1544 if (_blossom_set->trivial(blossom)) { |
|
1545 int bi = (*_node_index)[base]; |
|
1546 Value pot = (*_node_data)[bi].pot; |
|
1547 |
|
1548 _matching->set(base, matching); |
|
1549 _blossom_node_list.push_back(base); |
|
1550 _node_potential->set(base, pot); |
|
1551 } else { |
|
1552 |
|
1553 Value pot = (*_blossom_data)[blossom].pot; |
|
1554 int bn = _blossom_node_list.size(); |
|
1555 |
|
1556 std::vector<int> subblossoms; |
|
1557 _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
|
1558 int b = _blossom_set->find(base); |
|
1559 int ib = -1; |
|
1560 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
1561 if (subblossoms[i] == b) { ib = i; break; } |
|
1562 } |
|
1563 |
|
1564 for (int i = 1; i < int(subblossoms.size()); i += 2) { |
|
1565 int sb = subblossoms[(ib + i) % subblossoms.size()]; |
|
1566 int tb = subblossoms[(ib + i + 1) % subblossoms.size()]; |
|
1567 |
|
1568 Arc m = (*_blossom_data)[tb].next; |
|
1569 extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m)); |
|
1570 extractBlossom(tb, _graph.source(m), m); |
|
1571 } |
|
1572 extractBlossom(subblossoms[ib], base, matching); |
|
1573 |
|
1574 int en = _blossom_node_list.size(); |
|
1575 |
|
1576 _blossom_potential.push_back(BlossomVariable(bn, en, pot)); |
|
1577 } |
|
1578 } |
|
1579 |
|
1580 void extractMatching() { |
|
1581 std::vector<int> blossoms; |
|
1582 for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) { |
|
1583 blossoms.push_back(c); |
|
1584 } |
|
1585 |
|
1586 for (int i = 0; i < int(blossoms.size()); ++i) { |
|
1587 if ((*_blossom_data)[blossoms[i]].status == MATCHED) { |
|
1588 |
|
1589 Value offset = (*_blossom_data)[blossoms[i]].offset; |
|
1590 (*_blossom_data)[blossoms[i]].pot += 2 * offset; |
|
1591 for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]); |
|
1592 n != INVALID; ++n) { |
|
1593 (*_node_data)[(*_node_index)[n]].pot -= offset; |
|
1594 } |
|
1595 |
|
1596 Arc matching = (*_blossom_data)[blossoms[i]].next; |
|
1597 Node base = _graph.source(matching); |
|
1598 extractBlossom(blossoms[i], base, matching); |
|
1599 } else { |
|
1600 Node base = (*_blossom_data)[blossoms[i]].base; |
|
1601 extractBlossom(blossoms[i], base, INVALID); |
|
1602 } |
|
1603 } |
|
1604 } |
|
1605 |
|
1606 public: |
|
1607 |
|
1608 /// \brief Constructor |
|
1609 /// |
|
1610 /// Constructor. |
|
1611 MaxWeightedMatching(const Graph& graph, const WeightMap& weight) |
|
1612 : _graph(graph), _weight(weight), _matching(0), |
|
1613 _node_potential(0), _blossom_potential(), _blossom_node_list(), |
|
1614 _node_num(0), _blossom_num(0), |
|
1615 |
|
1616 _blossom_index(0), _blossom_set(0), _blossom_data(0), |
|
1617 _node_index(0), _node_heap_index(0), _node_data(0), |
|
1618 _tree_set_index(0), _tree_set(0), |
|
1619 |
|
1620 _delta1_index(0), _delta1(0), |
|
1621 _delta2_index(0), _delta2(0), |
|
1622 _delta3_index(0), _delta3(0), |
|
1623 _delta4_index(0), _delta4(0), |
|
1624 |
|
1625 _delta_sum() {} |
|
1626 |
|
1627 ~MaxWeightedMatching() { |
|
1628 destroyStructures(); |
|
1629 } |
|
1630 |
|
1631 /// \name Execution control |
|
1632 /// The simplest way to execute the algorithm is to use the |
|
1633 /// \c run() member function. |
|
1634 |
|
1635 ///@{ |
|
1636 |
|
1637 /// \brief Initialize the algorithm |
|
1638 /// |
|
1639 /// Initialize the algorithm |
|
1640 void init() { |
|
1641 createStructures(); |
|
1642 |
|
1643 for (ArcIt e(_graph); e != INVALID; ++e) { |
|
1644 _node_heap_index->set(e, BinHeap<Value, IntArcMap>::PRE_HEAP); |
|
1645 } |
|
1646 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
1647 _delta1_index->set(n, _delta1->PRE_HEAP); |
|
1648 } |
|
1649 for (EdgeIt e(_graph); e != INVALID; ++e) { |
|
1650 _delta3_index->set(e, _delta3->PRE_HEAP); |
|
1651 } |
|
1652 for (int i = 0; i < _blossom_num; ++i) { |
|
1653 _delta2_index->set(i, _delta2->PRE_HEAP); |
|
1654 _delta4_index->set(i, _delta4->PRE_HEAP); |
|
1655 } |
|
1656 |
|
1657 int index = 0; |
|
1658 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
1659 Value max = 0; |
|
1660 for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
|
1661 if (_graph.target(e) == n) continue; |
|
1662 if ((dualScale * _weight[e]) / 2 > max) { |
|
1663 max = (dualScale * _weight[e]) / 2; |
|
1664 } |
|
1665 } |
|
1666 _node_index->set(n, index); |
|
1667 (*_node_data)[index].pot = max; |
|
1668 _delta1->push(n, max); |
|
1669 int blossom = |
|
1670 _blossom_set->insert(n, std::numeric_limits<Value>::max()); |
|
1671 |
|
1672 _tree_set->insert(blossom); |
|
1673 |
|
1674 (*_blossom_data)[blossom].status = EVEN; |
|
1675 (*_blossom_data)[blossom].pred = INVALID; |
|
1676 (*_blossom_data)[blossom].next = INVALID; |
|
1677 (*_blossom_data)[blossom].pot = 0; |
|
1678 (*_blossom_data)[blossom].offset = 0; |
|
1679 ++index; |
|
1680 } |
|
1681 for (EdgeIt e(_graph); e != INVALID; ++e) { |
|
1682 int si = (*_node_index)[_graph.u(e)]; |
|
1683 int ti = (*_node_index)[_graph.v(e)]; |
|
1684 if (_graph.u(e) != _graph.v(e)) { |
|
1685 _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot - |
|
1686 dualScale * _weight[e]) / 2); |
|
1687 } |
|
1688 } |
|
1689 } |
|
1690 |
|
1691 /// \brief Starts the algorithm |
|
1692 /// |
|
1693 /// Starts the algorithm |
|
1694 void start() { |
|
1695 enum OpType { |
|
1696 D1, D2, D3, D4 |
|
1697 }; |
|
1698 |
|
1699 int unmatched = _node_num; |
|
1700 while (unmatched > 0) { |
|
1701 Value d1 = !_delta1->empty() ? |
|
1702 _delta1->prio() : std::numeric_limits<Value>::max(); |
|
1703 |
|
1704 Value d2 = !_delta2->empty() ? |
|
1705 _delta2->prio() : std::numeric_limits<Value>::max(); |
|
1706 |
|
1707 Value d3 = !_delta3->empty() ? |
|
1708 _delta3->prio() : std::numeric_limits<Value>::max(); |
|
1709 |
|
1710 Value d4 = !_delta4->empty() ? |
|
1711 _delta4->prio() : std::numeric_limits<Value>::max(); |
|
1712 |
|
1713 _delta_sum = d1; OpType ot = D1; |
|
1714 if (d2 < _delta_sum) { _delta_sum = d2; ot = D2; } |
|
1715 if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; } |
|
1716 if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; } |
|
1717 |
|
1718 |
|
1719 switch (ot) { |
|
1720 case D1: |
|
1721 { |
|
1722 Node n = _delta1->top(); |
|
1723 unmatchNode(n); |
|
1724 --unmatched; |
|
1725 } |
|
1726 break; |
|
1727 case D2: |
|
1728 { |
|
1729 int blossom = _delta2->top(); |
|
1730 Node n = _blossom_set->classTop(blossom); |
|
1731 Arc e = (*_node_data)[(*_node_index)[n]].heap.top(); |
|
1732 extendOnArc(e); |
|
1733 } |
|
1734 break; |
|
1735 case D3: |
|
1736 { |
|
1737 Edge e = _delta3->top(); |
|
1738 |
|
1739 int left_blossom = _blossom_set->find(_graph.u(e)); |
|
1740 int right_blossom = _blossom_set->find(_graph.v(e)); |
|
1741 |
|
1742 if (left_blossom == right_blossom) { |
|
1743 _delta3->pop(); |
|
1744 } else { |
|
1745 int left_tree; |
|
1746 if ((*_blossom_data)[left_blossom].status == EVEN) { |
|
1747 left_tree = _tree_set->find(left_blossom); |
|
1748 } else { |
|
1749 left_tree = -1; |
|
1750 ++unmatched; |
|
1751 } |
|
1752 int right_tree; |
|
1753 if ((*_blossom_data)[right_blossom].status == EVEN) { |
|
1754 right_tree = _tree_set->find(right_blossom); |
|
1755 } else { |
|
1756 right_tree = -1; |
|
1757 ++unmatched; |
|
1758 } |
|
1759 |
|
1760 if (left_tree == right_tree) { |
|
1761 shrinkOnEdge(e, left_tree); |
|
1762 } else { |
|
1763 augmentOnEdge(e); |
|
1764 unmatched -= 2; |
|
1765 } |
|
1766 } |
|
1767 } break; |
|
1768 case D4: |
|
1769 splitBlossom(_delta4->top()); |
|
1770 break; |
|
1771 } |
|
1772 } |
|
1773 extractMatching(); |
|
1774 } |
|
1775 |
|
1776 /// \brief Runs %MaxWeightedMatching algorithm. |
|
1777 /// |
|
1778 /// This method runs the %MaxWeightedMatching algorithm. |
|
1779 /// |
|
1780 /// \note mwm.run() is just a shortcut of the following code. |
|
1781 /// \code |
|
1782 /// mwm.init(); |
|
1783 /// mwm.start(); |
|
1784 /// \endcode |
|
1785 void run() { |
|
1786 init(); |
|
1787 start(); |
|
1788 } |
|
1789 |
|
1790 /// @} |
|
1791 |
|
1792 /// \name Primal solution |
|
1793 /// Functions to get the primal solution, ie. the matching. |
|
1794 |
|
1795 /// @{ |
|
1796 |
|
1797 /// \brief Returns the weight of the matching. |
|
1798 /// |
|
1799 /// Returns the weight of the matching. |
|
1800 Value matchingValue() const { |
|
1801 Value sum = 0; |
|
1802 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
1803 if ((*_matching)[n] != INVALID) { |
|
1804 sum += _weight[(*_matching)[n]]; |
|
1805 } |
|
1806 } |
|
1807 return sum /= 2; |
|
1808 } |
|
1809 |
|
1810 /// \brief Returns the cardinality of the matching. |
|
1811 /// |
|
1812 /// Returns the cardinality of the matching. |
|
1813 int matchingSize() const { |
|
1814 int num = 0; |
|
1815 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
1816 if ((*_matching)[n] != INVALID) { |
|
1817 ++num; |
|
1818 } |
|
1819 } |
|
1820 return num /= 2; |
|
1821 } |
|
1822 |
|
1823 /// \brief Returns true when the edge is in the matching. |
|
1824 /// |
|
1825 /// Returns true when the edge is in the matching. |
|
1826 bool matching(const Edge& edge) const { |
|
1827 return edge == (*_matching)[_graph.u(edge)]; |
|
1828 } |
|
1829 |
|
1830 /// \brief Returns the incident matching arc. |
|
1831 /// |
|
1832 /// Returns the incident matching arc from given node. If the |
|
1833 /// node is not matched then it gives back \c INVALID. |
|
1834 Arc matching(const Node& node) const { |
|
1835 return (*_matching)[node]; |
|
1836 } |
|
1837 |
|
1838 /// \brief Returns the mate of the node. |
|
1839 /// |
|
1840 /// Returns the adjancent node in a mathcing arc. If the node is |
|
1841 /// not matched then it gives back \c INVALID. |
|
1842 Node mate(const Node& node) const { |
|
1843 return (*_matching)[node] != INVALID ? |
|
1844 _graph.target((*_matching)[node]) : INVALID; |
|
1845 } |
|
1846 |
|
1847 /// @} |
|
1848 |
|
1849 /// \name Dual solution |
|
1850 /// Functions to get the dual solution. |
|
1851 |
|
1852 /// @{ |
|
1853 |
|
1854 /// \brief Returns the value of the dual solution. |
|
1855 /// |
|
1856 /// Returns the value of the dual solution. It should be equal to |
|
1857 /// the primal value scaled by \ref dualScale "dual scale". |
|
1858 Value dualValue() const { |
|
1859 Value sum = 0; |
|
1860 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
1861 sum += nodeValue(n); |
|
1862 } |
|
1863 for (int i = 0; i < blossomNum(); ++i) { |
|
1864 sum += blossomValue(i) * (blossomSize(i) / 2); |
|
1865 } |
|
1866 return sum; |
|
1867 } |
|
1868 |
|
1869 /// \brief Returns the value of the node. |
|
1870 /// |
|
1871 /// Returns the the value of the node. |
|
1872 Value nodeValue(const Node& n) const { |
|
1873 return (*_node_potential)[n]; |
|
1874 } |
|
1875 |
|
1876 /// \brief Returns the number of the blossoms in the basis. |
|
1877 /// |
|
1878 /// Returns the number of the blossoms in the basis. |
|
1879 /// \see BlossomIt |
|
1880 int blossomNum() const { |
|
1881 return _blossom_potential.size(); |
|
1882 } |
|
1883 |
|
1884 |
|
1885 /// \brief Returns the number of the nodes in the blossom. |
|
1886 /// |
|
1887 /// Returns the number of the nodes in the blossom. |
|
1888 int blossomSize(int k) const { |
|
1889 return _blossom_potential[k].end - _blossom_potential[k].begin; |
|
1890 } |
|
1891 |
|
1892 /// \brief Returns the value of the blossom. |
|
1893 /// |
|
1894 /// Returns the the value of the blossom. |
|
1895 /// \see BlossomIt |
|
1896 Value blossomValue(int k) const { |
|
1897 return _blossom_potential[k].value; |
|
1898 } |
|
1899 |
|
1900 /// \brief Iterator for obtaining the nodes of the blossom. |
|
1901 /// |
|
1902 /// Iterator for obtaining the nodes of the blossom. This class |
|
1903 /// provides a common lemon style iterator for listing a |
|
1904 /// subset of the nodes. |
|
1905 class BlossomIt { |
|
1906 public: |
|
1907 |
|
1908 /// \brief Constructor. |
|
1909 /// |
|
1910 /// Constructor to get the nodes of the variable. |
|
1911 BlossomIt(const MaxWeightedMatching& algorithm, int variable) |
|
1912 : _algorithm(&algorithm) |
|
1913 { |
|
1914 _index = _algorithm->_blossom_potential[variable].begin; |
|
1915 _last = _algorithm->_blossom_potential[variable].end; |
|
1916 } |
|
1917 |
|
1918 /// \brief Conversion to node. |
|
1919 /// |
|
1920 /// Conversion to node. |
|
1921 operator Node() const { |
|
1922 return _algorithm->_blossom_node_list[_index]; |
|
1923 } |
|
1924 |
|
1925 /// \brief Increment operator. |
|
1926 /// |
|
1927 /// Increment operator. |
|
1928 BlossomIt& operator++() { |
|
1929 ++_index; |
|
1930 return *this; |
|
1931 } |
|
1932 |
|
1933 /// \brief Validity checking |
|
1934 /// |
|
1935 /// Checks whether the iterator is invalid. |
|
1936 bool operator==(Invalid) const { return _index == _last; } |
|
1937 |
|
1938 /// \brief Validity checking |
|
1939 /// |
|
1940 /// Checks whether the iterator is valid. |
|
1941 bool operator!=(Invalid) const { return _index != _last; } |
|
1942 |
|
1943 private: |
|
1944 const MaxWeightedMatching* _algorithm; |
|
1945 int _last; |
|
1946 int _index; |
|
1947 }; |
|
1948 |
|
1949 /// @} |
|
1950 |
|
1951 }; |
|
1952 |
|
1953 /// \ingroup matching |
|
1954 /// |
|
1955 /// \brief Weighted perfect matching in general graphs |
|
1956 /// |
|
1957 /// This class provides an efficient implementation of Edmond's |
|
1958 /// maximum weighted perfect matching algorithm. The implementation |
|
1959 /// is based on extensive use of priority queues and provides |
|
1960 /// \f$O(nm\log(n))\f$ time complexity. |
|
1961 /// |
|
1962 /// The maximum weighted matching problem is to find undirected |
|
1963 /// edges in the graph with maximum overall weight and no two of |
|
1964 /// them shares their ends and covers all nodes. The problem can be |
|
1965 /// formulated with the following linear program. |
|
1966 /// \f[ \sum_{e \in \delta(u)}x_e = 1 \quad \forall u\in V\f] |
|
1967 /** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2} |
|
1968 \quad \forall B\in\mathcal{O}\f] */ |
|
1969 /// \f[x_e \ge 0\quad \forall e\in E\f] |
|
1970 /// \f[\max \sum_{e\in E}x_ew_e\f] |
|
1971 /// where \f$\delta(X)\f$ is the set of edges incident to a node in |
|
1972 /// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in |
|
1973 /// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality |
|
1974 /// subsets of the nodes. |
|
1975 /// |
|
1976 /// The algorithm calculates an optimal matching and a proof of the |
|
1977 /// optimality. The solution of the dual problem can be used to check |
|
1978 /// the result of the algorithm. The dual linear problem is the |
|
1979 /** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}z_B \ge |
|
1980 w_{uv} \quad \forall uv\in E\f] */ |
|
1981 /// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f] |
|
1982 /** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}} |
|
1983 \frac{\vert B \vert - 1}{2}z_B\f] */ |
|
1984 /// |
|
1985 /// The algorithm can be executed with \c run() or the \c init() and |
|
1986 /// then the \c start() member functions. After it the matching can |
|
1987 /// be asked with \c matching() or mate() functions. The dual |
|
1988 /// solution can be get with \c nodeValue(), \c blossomNum() and \c |
|
1989 /// blossomValue() members and \ref MaxWeightedMatching::BlossomIt |
|
1990 /// "BlossomIt" nested class which is able to iterate on the nodes |
|
1991 /// of a blossom. If the value type is integral then the dual |
|
1992 /// solution is multiplied by \ref MaxWeightedMatching::dualScale "4". |
|
1993 template <typename _Graph, |
|
1994 typename _WeightMap = typename _Graph::template EdgeMap<int> > |
|
1995 class MaxWeightedPerfectMatching { |
|
1996 public: |
|
1997 |
|
1998 typedef _Graph Graph; |
|
1999 typedef _WeightMap WeightMap; |
|
2000 typedef typename WeightMap::Value Value; |
|
2001 |
|
2002 /// \brief Scaling factor for dual solution |
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2003 /// |
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2004 /// Scaling factor for dual solution, it is equal to 4 or 1 |
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2005 /// according to the value type. |
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2006 static const int dualScale = |
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2007 std::numeric_limits<Value>::is_integer ? 4 : 1; |
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2008 |
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2009 typedef typename Graph::template NodeMap<typename Graph::Arc> |
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2010 MatchingMap; |
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2011 |
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2012 private: |
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2013 |
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2014 TEMPLATE_GRAPH_TYPEDEFS(Graph); |
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2015 |
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2016 typedef typename Graph::template NodeMap<Value> NodePotential; |
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2017 typedef std::vector<Node> BlossomNodeList; |
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2018 |
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2019 struct BlossomVariable { |
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2020 int begin, end; |
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2021 Value value; |
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2022 |
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2023 BlossomVariable(int _begin, int _end, Value _value) |
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2024 : begin(_begin), end(_end), value(_value) {} |
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2025 |
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2026 }; |
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2027 |
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2028 typedef std::vector<BlossomVariable> BlossomPotential; |
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2029 |
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2030 const Graph& _graph; |
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2031 const WeightMap& _weight; |
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2032 |
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2033 MatchingMap* _matching; |
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2034 |
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2035 NodePotential* _node_potential; |
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2036 |
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2037 BlossomPotential _blossom_potential; |
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2038 BlossomNodeList _blossom_node_list; |
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2039 |
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2040 int _node_num; |
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2041 int _blossom_num; |
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2042 |
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2043 typedef RangeMap<int> IntIntMap; |
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2044 |
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2045 enum Status { |
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2046 EVEN = -1, MATCHED = 0, ODD = 1 |
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2047 }; |
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2048 |
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2049 typedef HeapUnionFind<Value, IntNodeMap> BlossomSet; |
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2050 struct BlossomData { |
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2051 int tree; |
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2052 Status status; |
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2053 Arc pred, next; |
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2054 Value pot, offset; |
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2055 }; |
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2056 |
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2057 IntNodeMap *_blossom_index; |
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2058 BlossomSet *_blossom_set; |
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2059 RangeMap<BlossomData>* _blossom_data; |
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2060 |
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2061 IntNodeMap *_node_index; |
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2062 IntArcMap *_node_heap_index; |
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2063 |
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2064 struct NodeData { |
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2065 |
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2066 NodeData(IntArcMap& node_heap_index) |
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2067 : heap(node_heap_index) {} |
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2068 |
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2069 int blossom; |
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2070 Value pot; |
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2071 BinHeap<Value, IntArcMap> heap; |
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2072 std::map<int, Arc> heap_index; |
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2073 |
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2074 int tree; |
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2075 }; |
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2076 |
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2077 RangeMap<NodeData>* _node_data; |
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2078 |
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2079 typedef ExtendFindEnum<IntIntMap> TreeSet; |
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2080 |
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2081 IntIntMap *_tree_set_index; |
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2082 TreeSet *_tree_set; |
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2083 |
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2084 IntIntMap *_delta2_index; |
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2085 BinHeap<Value, IntIntMap> *_delta2; |
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2086 |
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2087 IntEdgeMap *_delta3_index; |
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2088 BinHeap<Value, IntEdgeMap> *_delta3; |
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2089 |
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2090 IntIntMap *_delta4_index; |
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2091 BinHeap<Value, IntIntMap> *_delta4; |
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2092 |
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2093 Value _delta_sum; |
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2094 |
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2095 void createStructures() { |
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2096 _node_num = countNodes(_graph); |
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2097 _blossom_num = _node_num * 3 / 2; |
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2098 |
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2099 if (!_matching) { |
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2100 _matching = new MatchingMap(_graph); |
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2101 } |
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2102 if (!_node_potential) { |
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2103 _node_potential = new NodePotential(_graph); |
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2104 } |
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2105 if (!_blossom_set) { |
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2106 _blossom_index = new IntNodeMap(_graph); |
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2107 _blossom_set = new BlossomSet(*_blossom_index); |
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2108 _blossom_data = new RangeMap<BlossomData>(_blossom_num); |
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2109 } |
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2110 |
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2111 if (!_node_index) { |
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2112 _node_index = new IntNodeMap(_graph); |
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2113 _node_heap_index = new IntArcMap(_graph); |
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2114 _node_data = new RangeMap<NodeData>(_node_num, |
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2115 NodeData(*_node_heap_index)); |
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2116 } |
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2117 |
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2118 if (!_tree_set) { |
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2119 _tree_set_index = new IntIntMap(_blossom_num); |
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2120 _tree_set = new TreeSet(*_tree_set_index); |
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2121 } |
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2122 if (!_delta2) { |
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2123 _delta2_index = new IntIntMap(_blossom_num); |
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2124 _delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index); |
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2125 } |
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2126 if (!_delta3) { |
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2127 _delta3_index = new IntEdgeMap(_graph); |
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2128 _delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index); |
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2129 } |
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2130 if (!_delta4) { |
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2131 _delta4_index = new IntIntMap(_blossom_num); |
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2132 _delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index); |
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2133 } |
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2134 } |
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2135 |
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2136 void destroyStructures() { |
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2137 _node_num = countNodes(_graph); |
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2138 _blossom_num = _node_num * 3 / 2; |
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2139 |
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2140 if (_matching) { |
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2141 delete _matching; |
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2142 } |
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2143 if (_node_potential) { |
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2144 delete _node_potential; |
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2145 } |
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2146 if (_blossom_set) { |
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2147 delete _blossom_index; |
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2148 delete _blossom_set; |
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2149 delete _blossom_data; |
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2150 } |
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2151 |
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2152 if (_node_index) { |
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2153 delete _node_index; |
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2154 delete _node_heap_index; |
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2155 delete _node_data; |
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2156 } |
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2157 |
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2158 if (_tree_set) { |
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2159 delete _tree_set_index; |
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2160 delete _tree_set; |
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2161 } |
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2162 if (_delta2) { |
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2163 delete _delta2_index; |
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2164 delete _delta2; |
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2165 } |
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2166 if (_delta3) { |
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2167 delete _delta3_index; |
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2168 delete _delta3; |
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2169 } |
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2170 if (_delta4) { |
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2171 delete _delta4_index; |
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2172 delete _delta4; |
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2173 } |
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2174 } |
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2175 |
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2176 void matchedToEven(int blossom, int tree) { |
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2177 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
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2178 _delta2->erase(blossom); |
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2179 } |
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2180 |
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2181 if (!_blossom_set->trivial(blossom)) { |
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2182 (*_blossom_data)[blossom].pot -= |
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2183 2 * (_delta_sum - (*_blossom_data)[blossom].offset); |
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2184 } |
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2185 |
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2186 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
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2187 n != INVALID; ++n) { |
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2188 |
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2189 _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
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2190 int ni = (*_node_index)[n]; |
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2191 |
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2192 (*_node_data)[ni].heap.clear(); |
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2193 (*_node_data)[ni].heap_index.clear(); |
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2194 |
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2195 (*_node_data)[ni].pot += _delta_sum - (*_blossom_data)[blossom].offset; |
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2196 |
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2197 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
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2198 Node v = _graph.source(e); |
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2199 int vb = _blossom_set->find(v); |
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2200 int vi = (*_node_index)[v]; |
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2201 |
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2202 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
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2203 dualScale * _weight[e]; |
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2204 |
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2205 if ((*_blossom_data)[vb].status == EVEN) { |
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2206 if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
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2207 _delta3->push(e, rw / 2); |
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2208 } |
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2209 } else { |
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2210 typename std::map<int, Arc>::iterator it = |
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2211 (*_node_data)[vi].heap_index.find(tree); |
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2212 |
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2213 if (it != (*_node_data)[vi].heap_index.end()) { |
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2214 if ((*_node_data)[vi].heap[it->second] > rw) { |
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2215 (*_node_data)[vi].heap.replace(it->second, e); |
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2216 (*_node_data)[vi].heap.decrease(e, rw); |
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2217 it->second = e; |
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2218 } |
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2219 } else { |
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2220 (*_node_data)[vi].heap.push(e, rw); |
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2221 (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
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2222 } |
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2223 |
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2224 if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
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2225 _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
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2226 |
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2227 if ((*_blossom_data)[vb].status == MATCHED) { |
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2228 if (_delta2->state(vb) != _delta2->IN_HEAP) { |
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2229 _delta2->push(vb, _blossom_set->classPrio(vb) - |
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2230 (*_blossom_data)[vb].offset); |
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2231 } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
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2232 (*_blossom_data)[vb].offset){ |
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2233 _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
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2234 (*_blossom_data)[vb].offset); |
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2235 } |
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2236 } |
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2237 } |
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2238 } |
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2239 } |
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2240 } |
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2241 (*_blossom_data)[blossom].offset = 0; |
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2242 } |
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2243 |
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2244 void matchedToOdd(int blossom) { |
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2245 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
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2246 _delta2->erase(blossom); |
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2247 } |
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2248 (*_blossom_data)[blossom].offset += _delta_sum; |
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2249 if (!_blossom_set->trivial(blossom)) { |
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2250 _delta4->push(blossom, (*_blossom_data)[blossom].pot / 2 + |
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2251 (*_blossom_data)[blossom].offset); |
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2252 } |
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2253 } |
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2254 |
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2255 void evenToMatched(int blossom, int tree) { |
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2256 if (!_blossom_set->trivial(blossom)) { |
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2257 (*_blossom_data)[blossom].pot += 2 * _delta_sum; |
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2258 } |
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2259 |
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2260 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
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2261 n != INVALID; ++n) { |
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2262 int ni = (*_node_index)[n]; |
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2263 (*_node_data)[ni].pot -= _delta_sum; |
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2264 |
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2265 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
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2266 Node v = _graph.source(e); |
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2267 int vb = _blossom_set->find(v); |
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2268 int vi = (*_node_index)[v]; |
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2269 |
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2270 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
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2271 dualScale * _weight[e]; |
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2272 |
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2273 if (vb == blossom) { |
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2274 if (_delta3->state(e) == _delta3->IN_HEAP) { |
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2275 _delta3->erase(e); |
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2276 } |
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2277 } else if ((*_blossom_data)[vb].status == EVEN) { |
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2278 |
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2279 if (_delta3->state(e) == _delta3->IN_HEAP) { |
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2280 _delta3->erase(e); |
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2281 } |
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2282 |
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2283 int vt = _tree_set->find(vb); |
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2284 |
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2285 if (vt != tree) { |
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2286 |
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2287 Arc r = _graph.oppositeArc(e); |
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2288 |
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2289 typename std::map<int, Arc>::iterator it = |
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2290 (*_node_data)[ni].heap_index.find(vt); |
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2291 |
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2292 if (it != (*_node_data)[ni].heap_index.end()) { |
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2293 if ((*_node_data)[ni].heap[it->second] > rw) { |
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2294 (*_node_data)[ni].heap.replace(it->second, r); |
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2295 (*_node_data)[ni].heap.decrease(r, rw); |
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2296 it->second = r; |
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2297 } |
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2298 } else { |
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2299 (*_node_data)[ni].heap.push(r, rw); |
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2300 (*_node_data)[ni].heap_index.insert(std::make_pair(vt, r)); |
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2301 } |
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2302 |
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2303 if ((*_blossom_set)[n] > (*_node_data)[ni].heap.prio()) { |
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2304 _blossom_set->decrease(n, (*_node_data)[ni].heap.prio()); |
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2305 |
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2306 if (_delta2->state(blossom) != _delta2->IN_HEAP) { |
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2307 _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
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2308 (*_blossom_data)[blossom].offset); |
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2309 } else if ((*_delta2)[blossom] > |
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2310 _blossom_set->classPrio(blossom) - |
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2311 (*_blossom_data)[blossom].offset){ |
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2312 _delta2->decrease(blossom, _blossom_set->classPrio(blossom) - |
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2313 (*_blossom_data)[blossom].offset); |
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2314 } |
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2315 } |
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2316 } |
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2317 } else { |
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2318 |
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2319 typename std::map<int, Arc>::iterator it = |
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2320 (*_node_data)[vi].heap_index.find(tree); |
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2321 |
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2322 if (it != (*_node_data)[vi].heap_index.end()) { |
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2323 (*_node_data)[vi].heap.erase(it->second); |
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2324 (*_node_data)[vi].heap_index.erase(it); |
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2325 if ((*_node_data)[vi].heap.empty()) { |
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2326 _blossom_set->increase(v, std::numeric_limits<Value>::max()); |
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2327 } else if ((*_blossom_set)[v] < (*_node_data)[vi].heap.prio()) { |
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2328 _blossom_set->increase(v, (*_node_data)[vi].heap.prio()); |
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2329 } |
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2330 |
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2331 if ((*_blossom_data)[vb].status == MATCHED) { |
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2332 if (_blossom_set->classPrio(vb) == |
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2333 std::numeric_limits<Value>::max()) { |
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2334 _delta2->erase(vb); |
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2335 } else if ((*_delta2)[vb] < _blossom_set->classPrio(vb) - |
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2336 (*_blossom_data)[vb].offset) { |
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2337 _delta2->increase(vb, _blossom_set->classPrio(vb) - |
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2338 (*_blossom_data)[vb].offset); |
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2339 } |
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2340 } |
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2341 } |
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2342 } |
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2343 } |
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2344 } |
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2345 } |
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2346 |
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2347 void oddToMatched(int blossom) { |
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2348 (*_blossom_data)[blossom].offset -= _delta_sum; |
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2349 |
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2350 if (_blossom_set->classPrio(blossom) != |
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2351 std::numeric_limits<Value>::max()) { |
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2352 _delta2->push(blossom, _blossom_set->classPrio(blossom) - |
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2353 (*_blossom_data)[blossom].offset); |
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2354 } |
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2355 |
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2356 if (!_blossom_set->trivial(blossom)) { |
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2357 _delta4->erase(blossom); |
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2358 } |
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2359 } |
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2360 |
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2361 void oddToEven(int blossom, int tree) { |
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2362 if (!_blossom_set->trivial(blossom)) { |
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2363 _delta4->erase(blossom); |
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2364 (*_blossom_data)[blossom].pot -= |
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2365 2 * (2 * _delta_sum - (*_blossom_data)[blossom].offset); |
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2366 } |
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2367 |
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2368 for (typename BlossomSet::ItemIt n(*_blossom_set, blossom); |
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2369 n != INVALID; ++n) { |
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2370 int ni = (*_node_index)[n]; |
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2371 |
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2372 _blossom_set->increase(n, std::numeric_limits<Value>::max()); |
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2373 |
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2374 (*_node_data)[ni].heap.clear(); |
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2375 (*_node_data)[ni].heap_index.clear(); |
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2376 (*_node_data)[ni].pot += |
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2377 2 * _delta_sum - (*_blossom_data)[blossom].offset; |
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2378 |
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2379 for (InArcIt e(_graph, n); e != INVALID; ++e) { |
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2380 Node v = _graph.source(e); |
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2381 int vb = _blossom_set->find(v); |
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2382 int vi = (*_node_index)[v]; |
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2383 |
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2384 Value rw = (*_node_data)[ni].pot + (*_node_data)[vi].pot - |
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2385 dualScale * _weight[e]; |
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2386 |
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2387 if ((*_blossom_data)[vb].status == EVEN) { |
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2388 if (_delta3->state(e) != _delta3->IN_HEAP && blossom != vb) { |
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2389 _delta3->push(e, rw / 2); |
|
2390 } |
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2391 } else { |
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2392 |
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2393 typename std::map<int, Arc>::iterator it = |
|
2394 (*_node_data)[vi].heap_index.find(tree); |
|
2395 |
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2396 if (it != (*_node_data)[vi].heap_index.end()) { |
|
2397 if ((*_node_data)[vi].heap[it->second] > rw) { |
|
2398 (*_node_data)[vi].heap.replace(it->second, e); |
|
2399 (*_node_data)[vi].heap.decrease(e, rw); |
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2400 it->second = e; |
|
2401 } |
|
2402 } else { |
|
2403 (*_node_data)[vi].heap.push(e, rw); |
|
2404 (*_node_data)[vi].heap_index.insert(std::make_pair(tree, e)); |
|
2405 } |
|
2406 |
|
2407 if ((*_blossom_set)[v] > (*_node_data)[vi].heap.prio()) { |
|
2408 _blossom_set->decrease(v, (*_node_data)[vi].heap.prio()); |
|
2409 |
|
2410 if ((*_blossom_data)[vb].status == MATCHED) { |
|
2411 if (_delta2->state(vb) != _delta2->IN_HEAP) { |
|
2412 _delta2->push(vb, _blossom_set->classPrio(vb) - |
|
2413 (*_blossom_data)[vb].offset); |
|
2414 } else if ((*_delta2)[vb] > _blossom_set->classPrio(vb) - |
|
2415 (*_blossom_data)[vb].offset) { |
|
2416 _delta2->decrease(vb, _blossom_set->classPrio(vb) - |
|
2417 (*_blossom_data)[vb].offset); |
|
2418 } |
|
2419 } |
|
2420 } |
|
2421 } |
|
2422 } |
|
2423 } |
|
2424 (*_blossom_data)[blossom].offset = 0; |
|
2425 } |
|
2426 |
|
2427 void alternatePath(int even, int tree) { |
|
2428 int odd; |
|
2429 |
|
2430 evenToMatched(even, tree); |
|
2431 (*_blossom_data)[even].status = MATCHED; |
|
2432 |
|
2433 while ((*_blossom_data)[even].pred != INVALID) { |
|
2434 odd = _blossom_set->find(_graph.target((*_blossom_data)[even].pred)); |
|
2435 (*_blossom_data)[odd].status = MATCHED; |
|
2436 oddToMatched(odd); |
|
2437 (*_blossom_data)[odd].next = (*_blossom_data)[odd].pred; |
|
2438 |
|
2439 even = _blossom_set->find(_graph.target((*_blossom_data)[odd].pred)); |
|
2440 (*_blossom_data)[even].status = MATCHED; |
|
2441 evenToMatched(even, tree); |
|
2442 (*_blossom_data)[even].next = |
|
2443 _graph.oppositeArc((*_blossom_data)[odd].pred); |
|
2444 } |
|
2445 |
|
2446 } |
|
2447 |
|
2448 void destroyTree(int tree) { |
|
2449 for (TreeSet::ItemIt b(*_tree_set, tree); b != INVALID; ++b) { |
|
2450 if ((*_blossom_data)[b].status == EVEN) { |
|
2451 (*_blossom_data)[b].status = MATCHED; |
|
2452 evenToMatched(b, tree); |
|
2453 } else if ((*_blossom_data)[b].status == ODD) { |
|
2454 (*_blossom_data)[b].status = MATCHED; |
|
2455 oddToMatched(b); |
|
2456 } |
|
2457 } |
|
2458 _tree_set->eraseClass(tree); |
|
2459 } |
|
2460 |
|
2461 void augmentOnEdge(const Edge& edge) { |
|
2462 |
|
2463 int left = _blossom_set->find(_graph.u(edge)); |
|
2464 int right = _blossom_set->find(_graph.v(edge)); |
|
2465 |
|
2466 int left_tree = _tree_set->find(left); |
|
2467 alternatePath(left, left_tree); |
|
2468 destroyTree(left_tree); |
|
2469 |
|
2470 int right_tree = _tree_set->find(right); |
|
2471 alternatePath(right, right_tree); |
|
2472 destroyTree(right_tree); |
|
2473 |
|
2474 (*_blossom_data)[left].next = _graph.direct(edge, true); |
|
2475 (*_blossom_data)[right].next = _graph.direct(edge, false); |
|
2476 } |
|
2477 |
|
2478 void extendOnArc(const Arc& arc) { |
|
2479 int base = _blossom_set->find(_graph.target(arc)); |
|
2480 int tree = _tree_set->find(base); |
|
2481 |
|
2482 int odd = _blossom_set->find(_graph.source(arc)); |
|
2483 _tree_set->insert(odd, tree); |
|
2484 (*_blossom_data)[odd].status = ODD; |
|
2485 matchedToOdd(odd); |
|
2486 (*_blossom_data)[odd].pred = arc; |
|
2487 |
|
2488 int even = _blossom_set->find(_graph.target((*_blossom_data)[odd].next)); |
|
2489 (*_blossom_data)[even].pred = (*_blossom_data)[even].next; |
|
2490 _tree_set->insert(even, tree); |
|
2491 (*_blossom_data)[even].status = EVEN; |
|
2492 matchedToEven(even, tree); |
|
2493 } |
|
2494 |
|
2495 void shrinkOnEdge(const Edge& edge, int tree) { |
|
2496 int nca = -1; |
|
2497 std::vector<int> left_path, right_path; |
|
2498 |
|
2499 { |
|
2500 std::set<int> left_set, right_set; |
|
2501 int left = _blossom_set->find(_graph.u(edge)); |
|
2502 left_path.push_back(left); |
|
2503 left_set.insert(left); |
|
2504 |
|
2505 int right = _blossom_set->find(_graph.v(edge)); |
|
2506 right_path.push_back(right); |
|
2507 right_set.insert(right); |
|
2508 |
|
2509 while (true) { |
|
2510 |
|
2511 if ((*_blossom_data)[left].pred == INVALID) break; |
|
2512 |
|
2513 left = |
|
2514 _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
|
2515 left_path.push_back(left); |
|
2516 left = |
|
2517 _blossom_set->find(_graph.target((*_blossom_data)[left].pred)); |
|
2518 left_path.push_back(left); |
|
2519 |
|
2520 left_set.insert(left); |
|
2521 |
|
2522 if (right_set.find(left) != right_set.end()) { |
|
2523 nca = left; |
|
2524 break; |
|
2525 } |
|
2526 |
|
2527 if ((*_blossom_data)[right].pred == INVALID) break; |
|
2528 |
|
2529 right = |
|
2530 _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
|
2531 right_path.push_back(right); |
|
2532 right = |
|
2533 _blossom_set->find(_graph.target((*_blossom_data)[right].pred)); |
|
2534 right_path.push_back(right); |
|
2535 |
|
2536 right_set.insert(right); |
|
2537 |
|
2538 if (left_set.find(right) != left_set.end()) { |
|
2539 nca = right; |
|
2540 break; |
|
2541 } |
|
2542 |
|
2543 } |
|
2544 |
|
2545 if (nca == -1) { |
|
2546 if ((*_blossom_data)[left].pred == INVALID) { |
|
2547 nca = right; |
|
2548 while (left_set.find(nca) == left_set.end()) { |
|
2549 nca = |
|
2550 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
2551 right_path.push_back(nca); |
|
2552 nca = |
|
2553 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
2554 right_path.push_back(nca); |
|
2555 } |
|
2556 } else { |
|
2557 nca = left; |
|
2558 while (right_set.find(nca) == right_set.end()) { |
|
2559 nca = |
|
2560 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
2561 left_path.push_back(nca); |
|
2562 nca = |
|
2563 _blossom_set->find(_graph.target((*_blossom_data)[nca].pred)); |
|
2564 left_path.push_back(nca); |
|
2565 } |
|
2566 } |
|
2567 } |
|
2568 } |
|
2569 |
|
2570 std::vector<int> subblossoms; |
|
2571 Arc prev; |
|
2572 |
|
2573 prev = _graph.direct(edge, true); |
|
2574 for (int i = 0; left_path[i] != nca; i += 2) { |
|
2575 subblossoms.push_back(left_path[i]); |
|
2576 (*_blossom_data)[left_path[i]].next = prev; |
|
2577 _tree_set->erase(left_path[i]); |
|
2578 |
|
2579 subblossoms.push_back(left_path[i + 1]); |
|
2580 (*_blossom_data)[left_path[i + 1]].status = EVEN; |
|
2581 oddToEven(left_path[i + 1], tree); |
|
2582 _tree_set->erase(left_path[i + 1]); |
|
2583 prev = _graph.oppositeArc((*_blossom_data)[left_path[i + 1]].pred); |
|
2584 } |
|
2585 |
|
2586 int k = 0; |
|
2587 while (right_path[k] != nca) ++k; |
|
2588 |
|
2589 subblossoms.push_back(nca); |
|
2590 (*_blossom_data)[nca].next = prev; |
|
2591 |
|
2592 for (int i = k - 2; i >= 0; i -= 2) { |
|
2593 subblossoms.push_back(right_path[i + 1]); |
|
2594 (*_blossom_data)[right_path[i + 1]].status = EVEN; |
|
2595 oddToEven(right_path[i + 1], tree); |
|
2596 _tree_set->erase(right_path[i + 1]); |
|
2597 |
|
2598 (*_blossom_data)[right_path[i + 1]].next = |
|
2599 (*_blossom_data)[right_path[i + 1]].pred; |
|
2600 |
|
2601 subblossoms.push_back(right_path[i]); |
|
2602 _tree_set->erase(right_path[i]); |
|
2603 } |
|
2604 |
|
2605 int surface = |
|
2606 _blossom_set->join(subblossoms.begin(), subblossoms.end()); |
|
2607 |
|
2608 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
2609 if (!_blossom_set->trivial(subblossoms[i])) { |
|
2610 (*_blossom_data)[subblossoms[i]].pot += 2 * _delta_sum; |
|
2611 } |
|
2612 (*_blossom_data)[subblossoms[i]].status = MATCHED; |
|
2613 } |
|
2614 |
|
2615 (*_blossom_data)[surface].pot = -2 * _delta_sum; |
|
2616 (*_blossom_data)[surface].offset = 0; |
|
2617 (*_blossom_data)[surface].status = EVEN; |
|
2618 (*_blossom_data)[surface].pred = (*_blossom_data)[nca].pred; |
|
2619 (*_blossom_data)[surface].next = (*_blossom_data)[nca].pred; |
|
2620 |
|
2621 _tree_set->insert(surface, tree); |
|
2622 _tree_set->erase(nca); |
|
2623 } |
|
2624 |
|
2625 void splitBlossom(int blossom) { |
|
2626 Arc next = (*_blossom_data)[blossom].next; |
|
2627 Arc pred = (*_blossom_data)[blossom].pred; |
|
2628 |
|
2629 int tree = _tree_set->find(blossom); |
|
2630 |
|
2631 (*_blossom_data)[blossom].status = MATCHED; |
|
2632 oddToMatched(blossom); |
|
2633 if (_delta2->state(blossom) == _delta2->IN_HEAP) { |
|
2634 _delta2->erase(blossom); |
|
2635 } |
|
2636 |
|
2637 std::vector<int> subblossoms; |
|
2638 _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
|
2639 |
|
2640 Value offset = (*_blossom_data)[blossom].offset; |
|
2641 int b = _blossom_set->find(_graph.source(pred)); |
|
2642 int d = _blossom_set->find(_graph.source(next)); |
|
2643 |
|
2644 int ib = -1, id = -1; |
|
2645 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
2646 if (subblossoms[i] == b) ib = i; |
|
2647 if (subblossoms[i] == d) id = i; |
|
2648 |
|
2649 (*_blossom_data)[subblossoms[i]].offset = offset; |
|
2650 if (!_blossom_set->trivial(subblossoms[i])) { |
|
2651 (*_blossom_data)[subblossoms[i]].pot -= 2 * offset; |
|
2652 } |
|
2653 if (_blossom_set->classPrio(subblossoms[i]) != |
|
2654 std::numeric_limits<Value>::max()) { |
|
2655 _delta2->push(subblossoms[i], |
|
2656 _blossom_set->classPrio(subblossoms[i]) - |
|
2657 (*_blossom_data)[subblossoms[i]].offset); |
|
2658 } |
|
2659 } |
|
2660 |
|
2661 if (id > ib ? ((id - ib) % 2 == 0) : ((ib - id) % 2 == 1)) { |
|
2662 for (int i = (id + 1) % subblossoms.size(); |
|
2663 i != ib; i = (i + 2) % subblossoms.size()) { |
|
2664 int sb = subblossoms[i]; |
|
2665 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
2666 (*_blossom_data)[sb].next = |
|
2667 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
2668 } |
|
2669 |
|
2670 for (int i = ib; i != id; i = (i + 2) % subblossoms.size()) { |
|
2671 int sb = subblossoms[i]; |
|
2672 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
2673 int ub = subblossoms[(i + 2) % subblossoms.size()]; |
|
2674 |
|
2675 (*_blossom_data)[sb].status = ODD; |
|
2676 matchedToOdd(sb); |
|
2677 _tree_set->insert(sb, tree); |
|
2678 (*_blossom_data)[sb].pred = pred; |
|
2679 (*_blossom_data)[sb].next = |
|
2680 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
2681 |
|
2682 pred = (*_blossom_data)[ub].next; |
|
2683 |
|
2684 (*_blossom_data)[tb].status = EVEN; |
|
2685 matchedToEven(tb, tree); |
|
2686 _tree_set->insert(tb, tree); |
|
2687 (*_blossom_data)[tb].pred = (*_blossom_data)[tb].next; |
|
2688 } |
|
2689 |
|
2690 (*_blossom_data)[subblossoms[id]].status = ODD; |
|
2691 matchedToOdd(subblossoms[id]); |
|
2692 _tree_set->insert(subblossoms[id], tree); |
|
2693 (*_blossom_data)[subblossoms[id]].next = next; |
|
2694 (*_blossom_data)[subblossoms[id]].pred = pred; |
|
2695 |
|
2696 } else { |
|
2697 |
|
2698 for (int i = (ib + 1) % subblossoms.size(); |
|
2699 i != id; i = (i + 2) % subblossoms.size()) { |
|
2700 int sb = subblossoms[i]; |
|
2701 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
2702 (*_blossom_data)[sb].next = |
|
2703 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
2704 } |
|
2705 |
|
2706 for (int i = id; i != ib; i = (i + 2) % subblossoms.size()) { |
|
2707 int sb = subblossoms[i]; |
|
2708 int tb = subblossoms[(i + 1) % subblossoms.size()]; |
|
2709 int ub = subblossoms[(i + 2) % subblossoms.size()]; |
|
2710 |
|
2711 (*_blossom_data)[sb].status = ODD; |
|
2712 matchedToOdd(sb); |
|
2713 _tree_set->insert(sb, tree); |
|
2714 (*_blossom_data)[sb].next = next; |
|
2715 (*_blossom_data)[sb].pred = |
|
2716 _graph.oppositeArc((*_blossom_data)[tb].next); |
|
2717 |
|
2718 (*_blossom_data)[tb].status = EVEN; |
|
2719 matchedToEven(tb, tree); |
|
2720 _tree_set->insert(tb, tree); |
|
2721 (*_blossom_data)[tb].pred = |
|
2722 (*_blossom_data)[tb].next = |
|
2723 _graph.oppositeArc((*_blossom_data)[ub].next); |
|
2724 next = (*_blossom_data)[ub].next; |
|
2725 } |
|
2726 |
|
2727 (*_blossom_data)[subblossoms[ib]].status = ODD; |
|
2728 matchedToOdd(subblossoms[ib]); |
|
2729 _tree_set->insert(subblossoms[ib], tree); |
|
2730 (*_blossom_data)[subblossoms[ib]].next = next; |
|
2731 (*_blossom_data)[subblossoms[ib]].pred = pred; |
|
2732 } |
|
2733 _tree_set->erase(blossom); |
|
2734 } |
|
2735 |
|
2736 void extractBlossom(int blossom, const Node& base, const Arc& matching) { |
|
2737 if (_blossom_set->trivial(blossom)) { |
|
2738 int bi = (*_node_index)[base]; |
|
2739 Value pot = (*_node_data)[bi].pot; |
|
2740 |
|
2741 _matching->set(base, matching); |
|
2742 _blossom_node_list.push_back(base); |
|
2743 _node_potential->set(base, pot); |
|
2744 } else { |
|
2745 |
|
2746 Value pot = (*_blossom_data)[blossom].pot; |
|
2747 int bn = _blossom_node_list.size(); |
|
2748 |
|
2749 std::vector<int> subblossoms; |
|
2750 _blossom_set->split(blossom, std::back_inserter(subblossoms)); |
|
2751 int b = _blossom_set->find(base); |
|
2752 int ib = -1; |
|
2753 for (int i = 0; i < int(subblossoms.size()); ++i) { |
|
2754 if (subblossoms[i] == b) { ib = i; break; } |
|
2755 } |
|
2756 |
|
2757 for (int i = 1; i < int(subblossoms.size()); i += 2) { |
|
2758 int sb = subblossoms[(ib + i) % subblossoms.size()]; |
|
2759 int tb = subblossoms[(ib + i + 1) % subblossoms.size()]; |
|
2760 |
|
2761 Arc m = (*_blossom_data)[tb].next; |
|
2762 extractBlossom(sb, _graph.target(m), _graph.oppositeArc(m)); |
|
2763 extractBlossom(tb, _graph.source(m), m); |
|
2764 } |
|
2765 extractBlossom(subblossoms[ib], base, matching); |
|
2766 |
|
2767 int en = _blossom_node_list.size(); |
|
2768 |
|
2769 _blossom_potential.push_back(BlossomVariable(bn, en, pot)); |
|
2770 } |
|
2771 } |
|
2772 |
|
2773 void extractMatching() { |
|
2774 std::vector<int> blossoms; |
|
2775 for (typename BlossomSet::ClassIt c(*_blossom_set); c != INVALID; ++c) { |
|
2776 blossoms.push_back(c); |
|
2777 } |
|
2778 |
|
2779 for (int i = 0; i < int(blossoms.size()); ++i) { |
|
2780 |
|
2781 Value offset = (*_blossom_data)[blossoms[i]].offset; |
|
2782 (*_blossom_data)[blossoms[i]].pot += 2 * offset; |
|
2783 for (typename BlossomSet::ItemIt n(*_blossom_set, blossoms[i]); |
|
2784 n != INVALID; ++n) { |
|
2785 (*_node_data)[(*_node_index)[n]].pot -= offset; |
|
2786 } |
|
2787 |
|
2788 Arc matching = (*_blossom_data)[blossoms[i]].next; |
|
2789 Node base = _graph.source(matching); |
|
2790 extractBlossom(blossoms[i], base, matching); |
|
2791 } |
|
2792 } |
|
2793 |
|
2794 public: |
|
2795 |
|
2796 /// \brief Constructor |
|
2797 /// |
|
2798 /// Constructor. |
|
2799 MaxWeightedPerfectMatching(const Graph& graph, const WeightMap& weight) |
|
2800 : _graph(graph), _weight(weight), _matching(0), |
|
2801 _node_potential(0), _blossom_potential(), _blossom_node_list(), |
|
2802 _node_num(0), _blossom_num(0), |
|
2803 |
|
2804 _blossom_index(0), _blossom_set(0), _blossom_data(0), |
|
2805 _node_index(0), _node_heap_index(0), _node_data(0), |
|
2806 _tree_set_index(0), _tree_set(0), |
|
2807 |
|
2808 _delta2_index(0), _delta2(0), |
|
2809 _delta3_index(0), _delta3(0), |
|
2810 _delta4_index(0), _delta4(0), |
|
2811 |
|
2812 _delta_sum() {} |
|
2813 |
|
2814 ~MaxWeightedPerfectMatching() { |
|
2815 destroyStructures(); |
|
2816 } |
|
2817 |
|
2818 /// \name Execution control |
|
2819 /// The simplest way to execute the algorithm is to use the |
|
2820 /// \c run() member function. |
|
2821 |
|
2822 ///@{ |
|
2823 |
|
2824 /// \brief Initialize the algorithm |
|
2825 /// |
|
2826 /// Initialize the algorithm |
|
2827 void init() { |
|
2828 createStructures(); |
|
2829 |
|
2830 for (ArcIt e(_graph); e != INVALID; ++e) { |
|
2831 _node_heap_index->set(e, BinHeap<Value, IntArcMap>::PRE_HEAP); |
|
2832 } |
|
2833 for (EdgeIt e(_graph); e != INVALID; ++e) { |
|
2834 _delta3_index->set(e, _delta3->PRE_HEAP); |
|
2835 } |
|
2836 for (int i = 0; i < _blossom_num; ++i) { |
|
2837 _delta2_index->set(i, _delta2->PRE_HEAP); |
|
2838 _delta4_index->set(i, _delta4->PRE_HEAP); |
|
2839 } |
|
2840 |
|
2841 int index = 0; |
|
2842 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
2843 Value max = - std::numeric_limits<Value>::max(); |
|
2844 for (OutArcIt e(_graph, n); e != INVALID; ++e) { |
|
2845 if (_graph.target(e) == n) continue; |
|
2846 if ((dualScale * _weight[e]) / 2 > max) { |
|
2847 max = (dualScale * _weight[e]) / 2; |
|
2848 } |
|
2849 } |
|
2850 _node_index->set(n, index); |
|
2851 (*_node_data)[index].pot = max; |
|
2852 int blossom = |
|
2853 _blossom_set->insert(n, std::numeric_limits<Value>::max()); |
|
2854 |
|
2855 _tree_set->insert(blossom); |
|
2856 |
|
2857 (*_blossom_data)[blossom].status = EVEN; |
|
2858 (*_blossom_data)[blossom].pred = INVALID; |
|
2859 (*_blossom_data)[blossom].next = INVALID; |
|
2860 (*_blossom_data)[blossom].pot = 0; |
|
2861 (*_blossom_data)[blossom].offset = 0; |
|
2862 ++index; |
|
2863 } |
|
2864 for (EdgeIt e(_graph); e != INVALID; ++e) { |
|
2865 int si = (*_node_index)[_graph.u(e)]; |
|
2866 int ti = (*_node_index)[_graph.v(e)]; |
|
2867 if (_graph.u(e) != _graph.v(e)) { |
|
2868 _delta3->push(e, ((*_node_data)[si].pot + (*_node_data)[ti].pot - |
|
2869 dualScale * _weight[e]) / 2); |
|
2870 } |
|
2871 } |
|
2872 } |
|
2873 |
|
2874 /// \brief Starts the algorithm |
|
2875 /// |
|
2876 /// Starts the algorithm |
|
2877 bool start() { |
|
2878 enum OpType { |
|
2879 D2, D3, D4 |
|
2880 }; |
|
2881 |
|
2882 int unmatched = _node_num; |
|
2883 while (unmatched > 0) { |
|
2884 Value d2 = !_delta2->empty() ? |
|
2885 _delta2->prio() : std::numeric_limits<Value>::max(); |
|
2886 |
|
2887 Value d3 = !_delta3->empty() ? |
|
2888 _delta3->prio() : std::numeric_limits<Value>::max(); |
|
2889 |
|
2890 Value d4 = !_delta4->empty() ? |
|
2891 _delta4->prio() : std::numeric_limits<Value>::max(); |
|
2892 |
|
2893 _delta_sum = d2; OpType ot = D2; |
|
2894 if (d3 < _delta_sum) { _delta_sum = d3; ot = D3; } |
|
2895 if (d4 < _delta_sum) { _delta_sum = d4; ot = D4; } |
|
2896 |
|
2897 if (_delta_sum == std::numeric_limits<Value>::max()) { |
|
2898 return false; |
|
2899 } |
|
2900 |
|
2901 switch (ot) { |
|
2902 case D2: |
|
2903 { |
|
2904 int blossom = _delta2->top(); |
|
2905 Node n = _blossom_set->classTop(blossom); |
|
2906 Arc e = (*_node_data)[(*_node_index)[n]].heap.top(); |
|
2907 extendOnArc(e); |
|
2908 } |
|
2909 break; |
|
2910 case D3: |
|
2911 { |
|
2912 Edge e = _delta3->top(); |
|
2913 |
|
2914 int left_blossom = _blossom_set->find(_graph.u(e)); |
|
2915 int right_blossom = _blossom_set->find(_graph.v(e)); |
|
2916 |
|
2917 if (left_blossom == right_blossom) { |
|
2918 _delta3->pop(); |
|
2919 } else { |
|
2920 int left_tree = _tree_set->find(left_blossom); |
|
2921 int right_tree = _tree_set->find(right_blossom); |
|
2922 |
|
2923 if (left_tree == right_tree) { |
|
2924 shrinkOnEdge(e, left_tree); |
|
2925 } else { |
|
2926 augmentOnEdge(e); |
|
2927 unmatched -= 2; |
|
2928 } |
|
2929 } |
|
2930 } break; |
|
2931 case D4: |
|
2932 splitBlossom(_delta4->top()); |
|
2933 break; |
|
2934 } |
|
2935 } |
|
2936 extractMatching(); |
|
2937 return true; |
|
2938 } |
|
2939 |
|
2940 /// \brief Runs %MaxWeightedPerfectMatching algorithm. |
|
2941 /// |
|
2942 /// This method runs the %MaxWeightedPerfectMatching algorithm. |
|
2943 /// |
|
2944 /// \note mwm.run() is just a shortcut of the following code. |
|
2945 /// \code |
|
2946 /// mwm.init(); |
|
2947 /// mwm.start(); |
|
2948 /// \endcode |
|
2949 bool run() { |
|
2950 init(); |
|
2951 return start(); |
|
2952 } |
|
2953 |
|
2954 /// @} |
|
2955 |
|
2956 /// \name Primal solution |
|
2957 /// Functions to get the primal solution, ie. the matching. |
|
2958 |
|
2959 /// @{ |
|
2960 |
|
2961 /// \brief Returns the matching value. |
|
2962 /// |
|
2963 /// Returns the matching value. |
|
2964 Value matchingValue() const { |
|
2965 Value sum = 0; |
|
2966 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
2967 if ((*_matching)[n] != INVALID) { |
|
2968 sum += _weight[(*_matching)[n]]; |
|
2969 } |
|
2970 } |
|
2971 return sum /= 2; |
|
2972 } |
|
2973 |
|
2974 /// \brief Returns true when the edge is in the matching. |
|
2975 /// |
|
2976 /// Returns true when the edge is in the matching. |
|
2977 bool matching(const Edge& edge) const { |
|
2978 return static_cast<const Edge&>((*_matching)[_graph.u(edge)]) == edge; |
|
2979 } |
|
2980 |
|
2981 /// \brief Returns the incident matching edge. |
|
2982 /// |
|
2983 /// Returns the incident matching arc from given edge. |
|
2984 Arc matching(const Node& node) const { |
|
2985 return (*_matching)[node]; |
|
2986 } |
|
2987 |
|
2988 /// \brief Returns the mate of the node. |
|
2989 /// |
|
2990 /// Returns the adjancent node in a mathcing arc. |
|
2991 Node mate(const Node& node) const { |
|
2992 return _graph.target((*_matching)[node]); |
|
2993 } |
|
2994 |
|
2995 /// @} |
|
2996 |
|
2997 /// \name Dual solution |
|
2998 /// Functions to get the dual solution. |
|
2999 |
|
3000 /// @{ |
|
3001 |
|
3002 /// \brief Returns the value of the dual solution. |
|
3003 /// |
|
3004 /// Returns the value of the dual solution. It should be equal to |
|
3005 /// the primal value scaled by \ref dualScale "dual scale". |
|
3006 Value dualValue() const { |
|
3007 Value sum = 0; |
|
3008 for (NodeIt n(_graph); n != INVALID; ++n) { |
|
3009 sum += nodeValue(n); |
|
3010 } |
|
3011 for (int i = 0; i < blossomNum(); ++i) { |
|
3012 sum += blossomValue(i) * (blossomSize(i) / 2); |
|
3013 } |
|
3014 return sum; |
|
3015 } |
|
3016 |
|
3017 /// \brief Returns the value of the node. |
|
3018 /// |
|
3019 /// Returns the the value of the node. |
|
3020 Value nodeValue(const Node& n) const { |
|
3021 return (*_node_potential)[n]; |
|
3022 } |
|
3023 |
|
3024 /// \brief Returns the number of the blossoms in the basis. |
|
3025 /// |
|
3026 /// Returns the number of the blossoms in the basis. |
|
3027 /// \see BlossomIt |
|
3028 int blossomNum() const { |
|
3029 return _blossom_potential.size(); |
|
3030 } |
|
3031 |
|
3032 |
|
3033 /// \brief Returns the number of the nodes in the blossom. |
|
3034 /// |
|
3035 /// Returns the number of the nodes in the blossom. |
|
3036 int blossomSize(int k) const { |
|
3037 return _blossom_potential[k].end - _blossom_potential[k].begin; |
|
3038 } |
|
3039 |
|
3040 /// \brief Returns the value of the blossom. |
|
3041 /// |
|
3042 /// Returns the the value of the blossom. |
|
3043 /// \see BlossomIt |
|
3044 Value blossomValue(int k) const { |
|
3045 return _blossom_potential[k].value; |
|
3046 } |
|
3047 |
|
3048 /// \brief Iterator for obtaining the nodes of the blossom. |
|
3049 /// |
|
3050 /// Iterator for obtaining the nodes of the blossom. This class |
|
3051 /// provides a common lemon style iterator for listing a |
|
3052 /// subset of the nodes. |
|
3053 class BlossomIt { |
|
3054 public: |
|
3055 |
|
3056 /// \brief Constructor. |
|
3057 /// |
|
3058 /// Constructor to get the nodes of the variable. |
|
3059 BlossomIt(const MaxWeightedPerfectMatching& algorithm, int variable) |
|
3060 : _algorithm(&algorithm) |
|
3061 { |
|
3062 _index = _algorithm->_blossom_potential[variable].begin; |
|
3063 _last = _algorithm->_blossom_potential[variable].end; |
|
3064 } |
|
3065 |
|
3066 /// \brief Conversion to node. |
|
3067 /// |
|
3068 /// Conversion to node. |
|
3069 operator Node() const { |
|
3070 return _algorithm->_blossom_node_list[_index]; |
|
3071 } |
|
3072 |
|
3073 /// \brief Increment operator. |
|
3074 /// |
|
3075 /// Increment operator. |
|
3076 BlossomIt& operator++() { |
|
3077 ++_index; |
|
3078 return *this; |
|
3079 } |
|
3080 |
|
3081 /// \brief Validity checking |
|
3082 /// |
|
3083 /// Checks whether the iterator is invalid. |
|
3084 bool operator==(Invalid) const { return _index == _last; } |
|
3085 |
|
3086 /// \brief Validity checking |
|
3087 /// |
|
3088 /// Checks whether the iterator is valid. |
|
3089 bool operator!=(Invalid) const { return _index != _last; } |
|
3090 |
|
3091 private: |
|
3092 const MaxWeightedPerfectMatching* _algorithm; |
|
3093 int _last; |
|
3094 int _index; |
|
3095 }; |
|
3096 |
|
3097 /// @} |
|
3098 |
|
3099 }; |
|
3100 |
|
3101 |
|
3102 } //END OF NAMESPACE LEMON |
|
3103 |
|
3104 #endif //LEMON_MAX_MATCHING_H |
|