1 | /* -*- C++ -*- |
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2 | * src/lemon/graph_utils.h - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Combinatorial Optimization Research Group, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | #ifndef LEMON_GRAPH_UTILS_H |
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18 | #define LEMON_GRAPH_UTILS_H |
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19 | |
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20 | #include <iterator> |
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21 | |
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22 | #include <lemon/invalid.h> |
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23 | |
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24 | ///\ingroup gutils |
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25 | ///\file |
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26 | ///\brief Graph utilities. |
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27 | /// |
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28 | ///\todo Please |
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29 | ///revise the documentation. |
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30 | /// |
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31 | |
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32 | |
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33 | namespace lemon { |
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34 | |
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35 | /// \addtogroup gutils |
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36 | /// @{ |
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37 | |
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38 | // counters in the graph |
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39 | /// \brief Function to count the items in the graph. |
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40 | /// |
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41 | /// This function counts the items in the graph. |
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42 | /// The complexity of the function is O(n) because |
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43 | /// it iterates on all of the items. |
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44 | |
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45 | template <typename Graph, typename ItemIt> |
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46 | inline int countItems(const Graph& _g) { |
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47 | int num = 0; |
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48 | for (ItemIt it(_g); it != INVALID; ++it) { |
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49 | ++num; |
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50 | } |
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51 | return num; |
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52 | } |
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53 | |
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54 | /// \brief Function to count the nodes in the graph. |
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55 | /// |
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56 | /// This function counts the nodes in the graph. |
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57 | /// The complexity of the function is O(n) but for some |
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58 | /// graph structure it is specialized to run in O(1). |
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59 | |
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60 | template <typename Graph> |
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61 | inline int countNodes(const Graph& _g) { |
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62 | return countItems<Graph, typename Graph::NodeIt>(_g); |
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63 | } |
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64 | |
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65 | /// \brief Function to count the edges in the graph. |
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66 | /// |
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67 | /// This function counts the edges in the graph. |
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68 | /// The complexity of the function is O(e) but for some |
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69 | /// graph structure it is specialized to run in O(1). |
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70 | template <typename Graph> |
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71 | inline int countEdges(const Graph& _g) { |
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72 | return countItems<Graph, typename Graph::EdgeIt>(_g); |
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73 | } |
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74 | |
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75 | /// \brief Function to count the symmetric edges in the graph. |
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76 | /// |
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77 | /// This function counts the symmetric edges in the graph. |
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78 | /// The complexity of the function is O(e) but for some |
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79 | /// graph structure it is specialized to run in O(1). |
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80 | template <typename Graph> |
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81 | inline int countSymEdges(const Graph& _g) { |
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82 | return countItems<Graph, typename Graph::SymEdgeIt>(_g); |
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83 | } |
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84 | |
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85 | template <typename Graph, typename DegIt> |
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86 | inline int countNodeDegree(const Graph& _g, const typename Graph::Node& _n) { |
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87 | int num = 0; |
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88 | for (DegIt it(_g, _n); it != INVALID; ++it) { |
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89 | ++num; |
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90 | } |
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91 | return num; |
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92 | } |
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93 | |
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94 | /// Finds an edge between two nodes of a graph. |
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95 | |
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96 | /// Finds an edge from node \c u to node \c v in graph \c g. |
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97 | /// |
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98 | /// If \c prev is \ref INVALID (this is the default value), then |
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99 | /// it finds the first edge from \c u to \c v. Otherwise it looks for |
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100 | /// the next edge from \c u to \c v after \c prev. |
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101 | /// \return The found edge or \ref INVALID if there is no such an edge. |
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102 | /// |
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103 | /// Thus you can iterate through each edge from \c u to \c v as it follows. |
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104 | /// \code |
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105 | /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) { |
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106 | /// ... |
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107 | /// } |
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108 | /// \endcode |
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109 | /// \todo We may want to use the \ref concept::GraphBase "GraphBase" |
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110 | /// interface here... |
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111 | /// \bug Untested ... |
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112 | template <typename Graph> |
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113 | typename Graph::Edge findEdge(const Graph &g, |
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114 | typename Graph::Node u, typename Graph::Node v, |
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115 | typename Graph::Edge prev = INVALID) |
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116 | { |
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117 | typename Graph::OutEdgeIt e(g,prev); |
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118 | if(prev==INVALID) g.first(e,u); |
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119 | else ++e; |
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120 | while(e!=INVALID && g.tail(e)!=v) ++e; |
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121 | return e; |
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122 | } |
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123 | |
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124 | ///\e |
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125 | |
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126 | ///\todo Please document. |
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127 | /// |
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128 | template <typename Graph> |
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129 | inline int countOutEdges(const Graph& _g, const typename Graph::Node& _n) { |
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130 | return countNodeDegree<Graph, typename Graph::OutEdgeIt>(_g, _n); |
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131 | } |
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132 | |
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133 | ///\e |
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134 | |
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135 | ///\todo Please document. |
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136 | /// |
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137 | template <typename Graph> |
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138 | inline int countInEdges(const Graph& _g, const typename Graph::Node& _n) { |
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139 | return countNodeDegree<Graph, typename Graph::InEdgeIt>(_g, _n); |
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140 | } |
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141 | |
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142 | // graph copy |
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143 | |
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144 | template < |
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145 | typename DestinationGraph, |
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146 | typename SourceGraph, |
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147 | typename NodeBijection> |
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148 | void copyNodes(DestinationGraph& _d, const SourceGraph& _s, |
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149 | NodeBijection& _nb) { |
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150 | for (typename SourceGraph::NodeIt it(_s); it != INVALID; ++it) { |
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151 | _nb[it] = _d.addNode(); |
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152 | } |
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153 | } |
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154 | |
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155 | template < |
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156 | typename DestinationGraph, |
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157 | typename SourceGraph, |
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158 | typename NodeBijection, |
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159 | typename EdgeBijection> |
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160 | void copyEdges(DestinationGraph& _d, const SourceGraph& _s, |
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161 | const NodeBijection& _nb, EdgeBijection& _eb) { |
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162 | for (typename SourceGraph::EdgeIt it(_s); it != INVALID; ++it) { |
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163 | _eb[it] = _d.addEdge(_nb[_s.tail(it)], _nb[_s.head(it)]); |
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164 | } |
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165 | } |
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166 | |
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167 | template < |
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168 | typename DestinationGraph, |
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169 | typename SourceGraph, |
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170 | typename NodeBijection, |
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171 | typename EdgeBijection> |
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172 | void copyGraph(DestinationGraph& _d, const SourceGraph& _s, |
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173 | NodeBijection& _nb, EdgeBijection& _eb) { |
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174 | nodeCopy(_d, _s, _nb); |
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175 | edgeCopy(_d, _s, _nb, _eb); |
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176 | } |
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177 | |
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178 | template < |
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179 | typename _DestinationGraph, |
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180 | typename _SourceGraph, |
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181 | typename _NodeBijection |
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182 | =typename _SourceGraph::template NodeMap<typename _DestinationGraph::Node>, |
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183 | typename _EdgeBijection |
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184 | =typename _SourceGraph::template EdgeMap<typename _DestinationGraph::Edge> |
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185 | > |
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186 | class GraphCopy { |
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187 | public: |
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188 | |
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189 | typedef _DestinationGraph DestinationGraph; |
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190 | typedef _SourceGraph SourceGraph; |
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191 | |
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192 | typedef _NodeBijection NodeBijection; |
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193 | typedef _EdgeBijection EdgeBijection; |
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194 | |
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195 | protected: |
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196 | |
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197 | NodeBijection node_bijection; |
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198 | EdgeBijection edge_bijection; |
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199 | |
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200 | public: |
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201 | |
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202 | GraphCopy(DestinationGraph& _d, const SourceGraph& _s) { |
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203 | copyGraph(_d, _s, node_bijection, edge_bijection); |
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204 | } |
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205 | |
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206 | const NodeBijection& getNodeBijection() const { |
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207 | return node_bijection; |
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208 | } |
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209 | |
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210 | const EdgeBijection& getEdgeBijection() const { |
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211 | return edge_bijection; |
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212 | } |
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213 | |
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214 | }; |
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215 | |
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216 | /// @} |
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217 | |
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218 | } //END OF NAMESPACE LEMON |
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219 | |
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220 | #endif |
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