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) 2003-2008 |
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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_DIJKSTRA_H |
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20 | #define LEMON_DIJKSTRA_H |
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21 | |
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22 | ///\ingroup shortest_path |
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23 | ///\file |
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24 | ///\brief Dijkstra algorithm. |
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25 | |
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26 | #include <limits> |
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27 | #include <lemon/list_graph.h> |
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28 | #include <lemon/bin_heap.h> |
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29 | #include <lemon/bits/path_dump.h> |
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30 | #include <lemon/core.h> |
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31 | #include <lemon/error.h> |
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32 | #include <lemon/maps.h> |
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33 | #include <lemon/path.h> |
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34 | |
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35 | namespace lemon { |
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36 | |
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37 | /// \brief Default operation traits for the Dijkstra algorithm class. |
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38 | /// |
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39 | /// This operation traits class defines all computational operations and |
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40 | /// constants which are used in the Dijkstra algorithm. |
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41 | template <typename Value> |
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42 | struct DijkstraDefaultOperationTraits { |
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43 | /// \brief Gives back the zero value of the type. |
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44 | static Value zero() { |
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45 | return static_cast<Value>(0); |
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46 | } |
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47 | /// \brief Gives back the sum of the given two elements. |
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48 | static Value plus(const Value& left, const Value& right) { |
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49 | return left + right; |
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50 | } |
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51 | /// \brief Gives back true only if the first value is less than the second. |
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52 | static bool less(const Value& left, const Value& right) { |
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53 | return left < right; |
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54 | } |
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55 | }; |
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56 | |
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57 | /// \brief Widest path operation traits for the Dijkstra algorithm class. |
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58 | /// |
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59 | /// This operation traits class defines all computational operations and |
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60 | /// constants which are used in the Dijkstra algorithm for widest path |
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61 | /// computation. |
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62 | /// |
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63 | /// \see DijkstraDefaultOperationTraits |
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64 | template <typename Value> |
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65 | struct DijkstraWidestPathOperationTraits { |
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66 | /// \brief Gives back the maximum value of the type. |
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67 | static Value zero() { |
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68 | return std::numeric_limits<Value>::max(); |
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69 | } |
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70 | /// \brief Gives back the minimum of the given two elements. |
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71 | static Value plus(const Value& left, const Value& right) { |
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72 | return std::min(left, right); |
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73 | } |
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74 | /// \brief Gives back true only if the first value is less than the second. |
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75 | static bool less(const Value& left, const Value& right) { |
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76 | return left < right; |
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77 | } |
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78 | }; |
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79 | |
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80 | ///Default traits class of Dijkstra class. |
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81 | |
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82 | ///Default traits class of Dijkstra class. |
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83 | ///\tparam GR The type of the digraph. |
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84 | ///\tparam LM The type of the length map. |
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85 | template<class GR, class LM> |
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86 | struct DijkstraDefaultTraits |
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87 | { |
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88 | ///The type of the digraph the algorithm runs on. |
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89 | typedef GR Digraph; |
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90 | |
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91 | ///The type of the map that stores the arc lengths. |
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92 | |
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93 | ///The type of the map that stores the arc lengths. |
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94 | ///It must meet the \ref concepts::ReadMap "ReadMap" concept. |
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95 | typedef LM LengthMap; |
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96 | ///The type of the length of the arcs. |
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97 | typedef typename LM::Value Value; |
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98 | |
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99 | /// Operation traits for Dijkstra algorithm. |
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100 | |
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101 | /// This class defines the operations that are used in the algorithm. |
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102 | /// \see DijkstraDefaultOperationTraits |
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103 | typedef DijkstraDefaultOperationTraits<Value> OperationTraits; |
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104 | |
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105 | /// The cross reference type used by the heap. |
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106 | |
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107 | /// The cross reference type used by the heap. |
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108 | /// Usually it is \c Digraph::NodeMap<int>. |
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109 | typedef typename Digraph::template NodeMap<int> HeapCrossRef; |
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110 | ///Instantiates a \ref HeapCrossRef. |
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111 | |
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112 | ///This function instantiates a \ref HeapCrossRef. |
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113 | /// \param g is the digraph, to which we would like to define the |
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114 | /// \ref HeapCrossRef. |
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115 | static HeapCrossRef *createHeapCrossRef(const Digraph &g) |
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116 | { |
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117 | return new HeapCrossRef(g); |
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118 | } |
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119 | |
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120 | ///The heap type used by the Dijkstra algorithm. |
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121 | |
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122 | ///The heap type used by the Dijkstra algorithm. |
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123 | /// |
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124 | ///\sa BinHeap |
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125 | ///\sa Dijkstra |
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126 | typedef BinHeap<typename LM::Value, HeapCrossRef, std::less<Value> > Heap; |
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127 | ///Instantiates a \ref Heap. |
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128 | |
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129 | ///This function instantiates a \ref Heap. |
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130 | static Heap *createHeap(HeapCrossRef& r) |
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131 | { |
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132 | return new Heap(r); |
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133 | } |
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134 | |
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135 | ///\brief The type of the map that stores the predecessor |
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136 | ///arcs of the shortest paths. |
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137 | /// |
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138 | ///The type of the map that stores the predecessor |
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139 | ///arcs of the shortest paths. |
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140 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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141 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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142 | ///Instantiates a \ref PredMap. |
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143 | |
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144 | ///This function instantiates a \ref PredMap. |
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145 | ///\param g is the digraph, to which we would like to define the |
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146 | ///\ref PredMap. |
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147 | ///\todo The digraph alone may be insufficient for the initialization |
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148 | static PredMap *createPredMap(const Digraph &g) |
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149 | { |
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150 | return new PredMap(g); |
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151 | } |
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152 | |
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153 | ///The type of the map that indicates which nodes are processed. |
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154 | |
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155 | ///The type of the map that indicates which nodes are processed. |
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156 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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157 | ///By default it is a NullMap. |
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158 | ///\todo If it is set to a real map, |
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159 | ///Dijkstra::processed() should read this. |
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160 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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161 | ///Instantiates a \ref ProcessedMap. |
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162 | |
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163 | ///This function instantiates a \ref ProcessedMap. |
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164 | ///\param g is the digraph, to which |
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165 | ///we would like to define the \ref ProcessedMap |
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166 | #ifdef DOXYGEN |
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167 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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168 | #else |
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169 | static ProcessedMap *createProcessedMap(const Digraph &) |
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170 | #endif |
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171 | { |
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172 | return new ProcessedMap(); |
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173 | } |
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174 | |
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175 | ///The type of the map that stores the distances of the nodes. |
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176 | |
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177 | ///The type of the map that stores the distances of the nodes. |
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178 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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179 | typedef typename Digraph::template NodeMap<typename LM::Value> DistMap; |
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180 | ///Instantiates a \ref DistMap. |
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181 | |
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182 | ///This function instantiates a \ref DistMap. |
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183 | ///\param g is the digraph, to which we would like to define |
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184 | ///the \ref DistMap |
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185 | static DistMap *createDistMap(const Digraph &g) |
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186 | { |
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187 | return new DistMap(g); |
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188 | } |
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189 | }; |
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190 | |
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191 | ///%Dijkstra algorithm class. |
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192 | |
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193 | /// \ingroup shortest_path |
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194 | ///This class provides an efficient implementation of the %Dijkstra algorithm. |
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195 | /// |
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196 | ///The arc lengths are passed to the algorithm using a |
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197 | ///\ref concepts::ReadMap "ReadMap", |
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198 | ///so it is easy to change it to any kind of length. |
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199 | ///The type of the length is determined by the |
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200 | ///\ref concepts::ReadMap::Value "Value" of the length map. |
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201 | ///It is also possible to change the underlying priority heap. |
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202 | /// |
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203 | ///There is also a \ref dijkstra() "function-type interface" for the |
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204 | ///%Dijkstra algorithm, which is convenient in the simplier cases and |
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205 | ///it can be used easier. |
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206 | /// |
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207 | ///\tparam GR The type of the digraph the algorithm runs on. |
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208 | ///The default value is \ref ListDigraph. |
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209 | ///The value of GR is not used directly by \ref Dijkstra, it is only |
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210 | ///passed to \ref DijkstraDefaultTraits. |
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211 | ///\tparam LM A readable arc map that determines the lengths of the |
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212 | ///arcs. It is read once for each arc, so the map may involve in |
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213 | ///relatively time consuming process to compute the arc lengths if |
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214 | ///it is necessary. The default map type is \ref |
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215 | ///concepts::Digraph::ArcMap "Digraph::ArcMap<int>". |
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216 | ///The value of LM is not used directly by \ref Dijkstra, it is only |
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217 | ///passed to \ref DijkstraDefaultTraits. |
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218 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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219 | ///The default traits class is \ref DijkstraDefaultTraits |
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220 | ///"DijkstraDefaultTraits<GR,LM>". See \ref DijkstraDefaultTraits |
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221 | ///for the documentation of a Dijkstra traits class. |
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222 | #ifdef DOXYGEN |
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223 | template <typename GR, typename LM, typename TR> |
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224 | #else |
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225 | template <typename GR=ListDigraph, |
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226 | typename LM=typename GR::template ArcMap<int>, |
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227 | typename TR=DijkstraDefaultTraits<GR,LM> > |
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228 | #endif |
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229 | class Dijkstra { |
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230 | public: |
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231 | ///\ref Exception for uninitialized parameters. |
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232 | |
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233 | ///This error represents problems in the initialization of the |
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234 | ///parameters of the algorithm. |
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235 | class UninitializedParameter : public lemon::UninitializedParameter { |
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236 | public: |
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237 | virtual const char* what() const throw() { |
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238 | return "lemon::Dijkstra::UninitializedParameter"; |
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239 | } |
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240 | }; |
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241 | |
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242 | ///The type of the digraph the algorithm runs on. |
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243 | typedef typename TR::Digraph Digraph; |
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244 | |
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245 | ///The type of the length of the arcs. |
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246 | typedef typename TR::LengthMap::Value Value; |
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247 | ///The type of the map that stores the arc lengths. |
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248 | typedef typename TR::LengthMap LengthMap; |
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249 | ///\brief The type of the map that stores the predecessor arcs of the |
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250 | ///shortest paths. |
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251 | typedef typename TR::PredMap PredMap; |
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252 | ///The type of the map that stores the distances of the nodes. |
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253 | typedef typename TR::DistMap DistMap; |
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254 | ///The type of the map that indicates which nodes are processed. |
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255 | typedef typename TR::ProcessedMap ProcessedMap; |
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256 | ///The type of the paths. |
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257 | typedef PredMapPath<Digraph, PredMap> Path; |
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258 | ///The cross reference type used for the current heap. |
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259 | typedef typename TR::HeapCrossRef HeapCrossRef; |
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260 | ///The heap type used by the algorithm. |
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261 | typedef typename TR::Heap Heap; |
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262 | ///The operation traits class. |
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263 | typedef typename TR::OperationTraits OperationTraits; |
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264 | |
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265 | ///The traits class. |
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266 | typedef TR Traits; |
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267 | |
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268 | private: |
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269 | |
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270 | typedef typename Digraph::Node Node; |
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271 | typedef typename Digraph::NodeIt NodeIt; |
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272 | typedef typename Digraph::Arc Arc; |
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273 | typedef typename Digraph::OutArcIt OutArcIt; |
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274 | |
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275 | //Pointer to the underlying digraph. |
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276 | const Digraph *G; |
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277 | //Pointer to the length map. |
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278 | const LengthMap *length; |
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279 | //Pointer to the map of predecessors arcs. |
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280 | PredMap *_pred; |
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281 | //Indicates if _pred is locally allocated (true) or not. |
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282 | bool local_pred; |
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283 | //Pointer to the map of distances. |
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284 | DistMap *_dist; |
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285 | //Indicates if _dist is locally allocated (true) or not. |
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286 | bool local_dist; |
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287 | //Pointer to the map of processed status of the nodes. |
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288 | ProcessedMap *_processed; |
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289 | //Indicates if _processed is locally allocated (true) or not. |
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290 | bool local_processed; |
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291 | //Pointer to the heap cross references. |
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292 | HeapCrossRef *_heap_cross_ref; |
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293 | //Indicates if _heap_cross_ref is locally allocated (true) or not. |
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294 | bool local_heap_cross_ref; |
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295 | //Pointer to the heap. |
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296 | Heap *_heap; |
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297 | //Indicates if _heap is locally allocated (true) or not. |
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298 | bool local_heap; |
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299 | |
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300 | ///Creates the maps if necessary. |
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301 | ///\todo Better memory allocation (instead of new). |
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302 | void create_maps() |
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303 | { |
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304 | if(!_pred) { |
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305 | local_pred = true; |
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306 | _pred = Traits::createPredMap(*G); |
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307 | } |
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308 | if(!_dist) { |
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309 | local_dist = true; |
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310 | _dist = Traits::createDistMap(*G); |
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311 | } |
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312 | if(!_processed) { |
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313 | local_processed = true; |
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314 | _processed = Traits::createProcessedMap(*G); |
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315 | } |
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316 | if (!_heap_cross_ref) { |
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317 | local_heap_cross_ref = true; |
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318 | _heap_cross_ref = Traits::createHeapCrossRef(*G); |
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319 | } |
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320 | if (!_heap) { |
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321 | local_heap = true; |
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322 | _heap = Traits::createHeap(*_heap_cross_ref); |
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323 | } |
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324 | } |
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325 | |
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326 | public: |
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327 | |
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328 | typedef Dijkstra Create; |
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329 | |
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330 | ///\name Named template parameters |
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331 | |
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332 | ///@{ |
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333 | |
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334 | template <class T> |
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335 | struct SetPredMapTraits : public Traits { |
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336 | typedef T PredMap; |
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337 | static PredMap *createPredMap(const Digraph &) |
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338 | { |
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339 | throw UninitializedParameter(); |
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340 | } |
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341 | }; |
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342 | ///\brief \ref named-templ-param "Named parameter" for setting |
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343 | ///\ref PredMap type. |
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344 | /// |
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345 | ///\ref named-templ-param "Named parameter" for setting |
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346 | ///\ref PredMap type. |
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347 | template <class T> |
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348 | struct SetPredMap |
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349 | : public Dijkstra< Digraph, LengthMap, SetPredMapTraits<T> > { |
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350 | typedef Dijkstra< Digraph, LengthMap, SetPredMapTraits<T> > Create; |
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351 | }; |
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352 | |
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353 | template <class T> |
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354 | struct SetDistMapTraits : public Traits { |
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355 | typedef T DistMap; |
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356 | static DistMap *createDistMap(const Digraph &) |
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357 | { |
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358 | throw UninitializedParameter(); |
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359 | } |
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360 | }; |
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361 | ///\brief \ref named-templ-param "Named parameter" for setting |
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362 | ///\ref DistMap type. |
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363 | /// |
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364 | ///\ref named-templ-param "Named parameter" for setting |
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365 | ///\ref DistMap type. |
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366 | template <class T> |
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367 | struct SetDistMap |
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368 | : public Dijkstra< Digraph, LengthMap, SetDistMapTraits<T> > { |
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369 | typedef Dijkstra< Digraph, LengthMap, SetDistMapTraits<T> > Create; |
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370 | }; |
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371 | |
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372 | template <class T> |
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373 | struct SetProcessedMapTraits : public Traits { |
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374 | typedef T ProcessedMap; |
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375 | static ProcessedMap *createProcessedMap(const Digraph &) |
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376 | { |
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377 | throw UninitializedParameter(); |
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378 | } |
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379 | }; |
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380 | ///\brief \ref named-templ-param "Named parameter" for setting |
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381 | ///\ref ProcessedMap type. |
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382 | /// |
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383 | ///\ref named-templ-param "Named parameter" for setting |
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384 | ///\ref ProcessedMap type. |
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385 | template <class T> |
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386 | struct SetProcessedMap |
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387 | : public Dijkstra< Digraph, LengthMap, SetProcessedMapTraits<T> > { |
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388 | typedef Dijkstra< Digraph, LengthMap, SetProcessedMapTraits<T> > Create; |
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389 | }; |
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390 | |
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391 | struct SetStandardProcessedMapTraits : public Traits { |
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392 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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393 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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394 | { |
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395 | return new ProcessedMap(g); |
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396 | } |
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397 | }; |
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398 | ///\brief \ref named-templ-param "Named parameter" for setting |
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399 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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400 | /// |
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401 | ///\ref named-templ-param "Named parameter" for setting |
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402 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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403 | ///If you don't set it explicitly, it will be automatically allocated. |
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404 | struct SetStandardProcessedMap |
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405 | : public Dijkstra< Digraph, LengthMap, SetStandardProcessedMapTraits > { |
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406 | typedef Dijkstra< Digraph, LengthMap, SetStandardProcessedMapTraits > |
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407 | Create; |
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408 | }; |
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409 | |
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410 | template <class H, class CR> |
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411 | struct SetHeapTraits : public Traits { |
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412 | typedef CR HeapCrossRef; |
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413 | typedef H Heap; |
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414 | static HeapCrossRef *createHeapCrossRef(const Digraph &) { |
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415 | throw UninitializedParameter(); |
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416 | } |
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417 | static Heap *createHeap(HeapCrossRef &) |
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418 | { |
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419 | throw UninitializedParameter(); |
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420 | } |
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421 | }; |
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422 | ///\brief \ref named-templ-param "Named parameter" for setting |
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423 | ///heap and cross reference type |
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424 | /// |
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425 | ///\ref named-templ-param "Named parameter" for setting heap and cross |
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426 | ///reference type. |
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427 | template <class H, class CR = typename Digraph::template NodeMap<int> > |
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428 | struct SetHeap |
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429 | : public Dijkstra< Digraph, LengthMap, SetHeapTraits<H, CR> > { |
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430 | typedef Dijkstra< Digraph, LengthMap, SetHeapTraits<H, CR> > Create; |
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431 | }; |
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432 | |
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433 | template <class H, class CR> |
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434 | struct SetStandardHeapTraits : public Traits { |
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435 | typedef CR HeapCrossRef; |
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436 | typedef H Heap; |
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437 | static HeapCrossRef *createHeapCrossRef(const Digraph &G) { |
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438 | return new HeapCrossRef(G); |
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439 | } |
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440 | static Heap *createHeap(HeapCrossRef &R) |
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441 | { |
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442 | return new Heap(R); |
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443 | } |
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444 | }; |
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445 | ///\brief \ref named-templ-param "Named parameter" for setting |
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446 | ///heap and cross reference type with automatic allocation |
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447 | /// |
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448 | ///\ref named-templ-param "Named parameter" for setting heap and cross |
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449 | ///reference type. It can allocate the heap and the cross reference |
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450 | ///object if the cross reference's constructor waits for the digraph as |
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451 | ///parameter and the heap's constructor waits for the cross reference. |
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452 | template <class H, class CR = typename Digraph::template NodeMap<int> > |
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453 | struct SetStandardHeap |
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454 | : public Dijkstra< Digraph, LengthMap, SetStandardHeapTraits<H, CR> > { |
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455 | typedef Dijkstra< Digraph, LengthMap, SetStandardHeapTraits<H, CR> > |
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456 | Create; |
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457 | }; |
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458 | |
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459 | template <class T> |
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460 | struct SetOperationTraitsTraits : public Traits { |
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461 | typedef T OperationTraits; |
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462 | }; |
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463 | |
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464 | /// \brief \ref named-templ-param "Named parameter" for setting |
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465 | ///\ref OperationTraits type |
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466 | /// |
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467 | ///\ref named-templ-param "Named parameter" for setting |
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468 | ///\ref OperationTraits type. |
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469 | template <class T> |
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470 | struct SetOperationTraits |
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471 | : public Dijkstra<Digraph, LengthMap, SetOperationTraitsTraits<T> > { |
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472 | typedef Dijkstra<Digraph, LengthMap, SetOperationTraitsTraits<T> > |
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473 | Create; |
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474 | }; |
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475 | |
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476 | ///@} |
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477 | |
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478 | protected: |
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479 | |
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480 | Dijkstra() {} |
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481 | |
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482 | public: |
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483 | |
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484 | ///Constructor. |
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485 | |
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486 | ///Constructor. |
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487 | ///\param _g The digraph the algorithm runs on. |
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488 | ///\param _length The length map used by the algorithm. |
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489 | Dijkstra(const Digraph& _g, const LengthMap& _length) : |
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490 | G(&_g), length(&_length), |
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491 | _pred(NULL), local_pred(false), |
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492 | _dist(NULL), local_dist(false), |
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493 | _processed(NULL), local_processed(false), |
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494 | _heap_cross_ref(NULL), local_heap_cross_ref(false), |
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495 | _heap(NULL), local_heap(false) |
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496 | { } |
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497 | |
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498 | ///Destructor. |
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499 | ~Dijkstra() |
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500 | { |
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501 | if(local_pred) delete _pred; |
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502 | if(local_dist) delete _dist; |
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503 | if(local_processed) delete _processed; |
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504 | if(local_heap_cross_ref) delete _heap_cross_ref; |
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505 | if(local_heap) delete _heap; |
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506 | } |
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507 | |
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508 | ///Sets the length map. |
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509 | |
---|
510 | ///Sets the length map. |
---|
511 | ///\return <tt> (*this) </tt> |
---|
512 | Dijkstra &lengthMap(const LengthMap &m) |
---|
513 | { |
---|
514 | length = &m; |
---|
515 | return *this; |
---|
516 | } |
---|
517 | |
---|
518 | ///Sets the map that stores the predecessor arcs. |
---|
519 | |
---|
520 | ///Sets the map that stores the predecessor arcs. |
---|
521 | ///If you don't use this function before calling \ref run(), |
---|
522 | ///it will allocate one. The destructor deallocates this |
---|
523 | ///automatically allocated map, of course. |
---|
524 | ///\return <tt> (*this) </tt> |
---|
525 | Dijkstra &predMap(PredMap &m) |
---|
526 | { |
---|
527 | if(local_pred) { |
---|
528 | delete _pred; |
---|
529 | local_pred=false; |
---|
530 | } |
---|
531 | _pred = &m; |
---|
532 | return *this; |
---|
533 | } |
---|
534 | |
---|
535 | ///Sets the map that indicates which nodes are processed. |
---|
536 | |
---|
537 | ///Sets the map that indicates which nodes are processed. |
---|
538 | ///If you don't use this function before calling \ref run(), |
---|
539 | ///it will allocate one. The destructor deallocates this |
---|
540 | ///automatically allocated map, of course. |
---|
541 | ///\return <tt> (*this) </tt> |
---|
542 | Dijkstra &processedMap(ProcessedMap &m) |
---|
543 | { |
---|
544 | if(local_processed) { |
---|
545 | delete _processed; |
---|
546 | local_processed=false; |
---|
547 | } |
---|
548 | _processed = &m; |
---|
549 | return *this; |
---|
550 | } |
---|
551 | |
---|
552 | ///Sets the map that stores the distances of the nodes. |
---|
553 | |
---|
554 | ///Sets the map that stores the distances of the nodes calculated by the |
---|
555 | ///algorithm. |
---|
556 | ///If you don't use this function before calling \ref run(), |
---|
557 | ///it will allocate one. The destructor deallocates this |
---|
558 | ///automatically allocated map, of course. |
---|
559 | ///\return <tt> (*this) </tt> |
---|
560 | Dijkstra &distMap(DistMap &m) |
---|
561 | { |
---|
562 | if(local_dist) { |
---|
563 | delete _dist; |
---|
564 | local_dist=false; |
---|
565 | } |
---|
566 | _dist = &m; |
---|
567 | return *this; |
---|
568 | } |
---|
569 | |
---|
570 | ///Sets the heap and the cross reference used by algorithm. |
---|
571 | |
---|
572 | ///Sets the heap and the cross reference used by algorithm. |
---|
573 | ///If you don't use this function before calling \ref run(), |
---|
574 | ///it will allocate one. The destructor deallocates this |
---|
575 | ///automatically allocated heap and cross reference, of course. |
---|
576 | ///\return <tt> (*this) </tt> |
---|
577 | Dijkstra &heap(Heap& hp, HeapCrossRef &cr) |
---|
578 | { |
---|
579 | if(local_heap_cross_ref) { |
---|
580 | delete _heap_cross_ref; |
---|
581 | local_heap_cross_ref=false; |
---|
582 | } |
---|
583 | _heap_cross_ref = &cr; |
---|
584 | if(local_heap) { |
---|
585 | delete _heap; |
---|
586 | local_heap=false; |
---|
587 | } |
---|
588 | _heap = &hp; |
---|
589 | return *this; |
---|
590 | } |
---|
591 | |
---|
592 | private: |
---|
593 | |
---|
594 | void finalizeNodeData(Node v,Value dst) |
---|
595 | { |
---|
596 | _processed->set(v,true); |
---|
597 | _dist->set(v, dst); |
---|
598 | } |
---|
599 | |
---|
600 | public: |
---|
601 | |
---|
602 | ///\name Execution control |
---|
603 | ///The simplest way to execute the algorithm is to use one of the |
---|
604 | ///member functions called \ref lemon::Dijkstra::run() "run()". |
---|
605 | ///\n |
---|
606 | ///If you need more control on the execution, first you must call |
---|
607 | ///\ref lemon::Dijkstra::init() "init()", then you can add several |
---|
608 | ///source nodes with \ref lemon::Dijkstra::addSource() "addSource()". |
---|
609 | ///Finally \ref lemon::Dijkstra::start() "start()" will perform the |
---|
610 | ///actual path computation. |
---|
611 | |
---|
612 | ///@{ |
---|
613 | |
---|
614 | ///Initializes the internal data structures. |
---|
615 | |
---|
616 | ///Initializes the internal data structures. |
---|
617 | /// |
---|
618 | void init() |
---|
619 | { |
---|
620 | create_maps(); |
---|
621 | _heap->clear(); |
---|
622 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
---|
623 | _pred->set(u,INVALID); |
---|
624 | _processed->set(u,false); |
---|
625 | _heap_cross_ref->set(u,Heap::PRE_HEAP); |
---|
626 | } |
---|
627 | } |
---|
628 | |
---|
629 | ///Adds a new source node. |
---|
630 | |
---|
631 | ///Adds a new source node to the priority heap. |
---|
632 | ///The optional second parameter is the initial distance of the node. |
---|
633 | /// |
---|
634 | ///The function checks if the node has already been added to the heap and |
---|
635 | ///it is pushed to the heap only if either it was not in the heap |
---|
636 | ///or the shortest path found till then is shorter than \c dst. |
---|
637 | void addSource(Node s,Value dst=OperationTraits::zero()) |
---|
638 | { |
---|
639 | if(_heap->state(s) != Heap::IN_HEAP) { |
---|
640 | _heap->push(s,dst); |
---|
641 | } else if(OperationTraits::less((*_heap)[s], dst)) { |
---|
642 | _heap->set(s,dst); |
---|
643 | _pred->set(s,INVALID); |
---|
644 | } |
---|
645 | } |
---|
646 | |
---|
647 | ///Processes the next node in the priority heap |
---|
648 | |
---|
649 | ///Processes the next node in the priority heap. |
---|
650 | /// |
---|
651 | ///\return The processed node. |
---|
652 | /// |
---|
653 | ///\warning The priority heap must not be empty. |
---|
654 | Node processNextNode() |
---|
655 | { |
---|
656 | Node v=_heap->top(); |
---|
657 | Value oldvalue=_heap->prio(); |
---|
658 | _heap->pop(); |
---|
659 | finalizeNodeData(v,oldvalue); |
---|
660 | |
---|
661 | for(OutArcIt e(*G,v); e!=INVALID; ++e) { |
---|
662 | Node w=G->target(e); |
---|
663 | switch(_heap->state(w)) { |
---|
664 | case Heap::PRE_HEAP: |
---|
665 | _heap->push(w,OperationTraits::plus(oldvalue, (*length)[e])); |
---|
666 | _pred->set(w,e); |
---|
667 | break; |
---|
668 | case Heap::IN_HEAP: |
---|
669 | { |
---|
670 | Value newvalue = OperationTraits::plus(oldvalue, (*length)[e]); |
---|
671 | if ( OperationTraits::less(newvalue, (*_heap)[w]) ) { |
---|
672 | _heap->decrease(w, newvalue); |
---|
673 | _pred->set(w,e); |
---|
674 | } |
---|
675 | } |
---|
676 | break; |
---|
677 | case Heap::POST_HEAP: |
---|
678 | break; |
---|
679 | } |
---|
680 | } |
---|
681 | return v; |
---|
682 | } |
---|
683 | |
---|
684 | ///The next node to be processed. |
---|
685 | |
---|
686 | ///Returns the next node to be processed or \c INVALID if the |
---|
687 | ///priority heap is empty. |
---|
688 | Node nextNode() const |
---|
689 | { |
---|
690 | return !_heap->empty()?_heap->top():INVALID; |
---|
691 | } |
---|
692 | |
---|
693 | ///\brief Returns \c false if there are nodes |
---|
694 | ///to be processed. |
---|
695 | /// |
---|
696 | ///Returns \c false if there are nodes |
---|
697 | ///to be processed in the priority heap. |
---|
698 | bool emptyQueue() const { return _heap->empty(); } |
---|
699 | |
---|
700 | ///Returns the number of the nodes to be processed in the priority heap |
---|
701 | |
---|
702 | ///Returns the number of the nodes to be processed in the priority heap. |
---|
703 | /// |
---|
704 | int queueSize() const { return _heap->size(); } |
---|
705 | |
---|
706 | ///Executes the algorithm. |
---|
707 | |
---|
708 | ///Executes the algorithm. |
---|
709 | /// |
---|
710 | ///This method runs the %Dijkstra algorithm from the root node(s) |
---|
711 | ///in order to compute the shortest path to each node. |
---|
712 | /// |
---|
713 | ///The algorithm computes |
---|
714 | ///- the shortest path tree (forest), |
---|
715 | ///- the distance of each node from the root(s). |
---|
716 | /// |
---|
717 | ///\pre init() must be called and at least one root node should be |
---|
718 | ///added with addSource() before using this function. |
---|
719 | /// |
---|
720 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
721 | ///\code |
---|
722 | /// while ( !d.emptyQueue() ) { |
---|
723 | /// d.processNextNode(); |
---|
724 | /// } |
---|
725 | ///\endcode |
---|
726 | void start() |
---|
727 | { |
---|
728 | while ( !emptyQueue() ) processNextNode(); |
---|
729 | } |
---|
730 | |
---|
731 | ///Executes the algorithm until the given target node is reached. |
---|
732 | |
---|
733 | ///Executes the algorithm until the given target node is reached. |
---|
734 | /// |
---|
735 | ///This method runs the %Dijkstra algorithm from the root node(s) |
---|
736 | ///in order to compute the shortest path to \c dest. |
---|
737 | /// |
---|
738 | ///The algorithm computes |
---|
739 | ///- the shortest path to \c dest, |
---|
740 | ///- the distance of \c dest from the root(s). |
---|
741 | /// |
---|
742 | ///\pre init() must be called and at least one root node should be |
---|
743 | ///added with addSource() before using this function. |
---|
744 | void start(Node dest) |
---|
745 | { |
---|
746 | while ( !_heap->empty() && _heap->top()!=dest ) processNextNode(); |
---|
747 | if ( !_heap->empty() ) finalizeNodeData(_heap->top(),_heap->prio()); |
---|
748 | } |
---|
749 | |
---|
750 | ///Executes the algorithm until a condition is met. |
---|
751 | |
---|
752 | ///Executes the algorithm until a condition is met. |
---|
753 | /// |
---|
754 | ///This method runs the %Dijkstra algorithm from the root node(s) in |
---|
755 | ///order to compute the shortest path to a node \c v with |
---|
756 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
757 | /// |
---|
758 | ///\param nm A \c bool (or convertible) node map. The algorithm |
---|
759 | ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
---|
760 | /// |
---|
761 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
762 | ///\c INVALID if no such node was found. |
---|
763 | /// |
---|
764 | ///\pre init() must be called and at least one root node should be |
---|
765 | ///added with addSource() before using this function. |
---|
766 | template<class NodeBoolMap> |
---|
767 | Node start(const NodeBoolMap &nm) |
---|
768 | { |
---|
769 | while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode(); |
---|
770 | if ( _heap->empty() ) return INVALID; |
---|
771 | finalizeNodeData(_heap->top(),_heap->prio()); |
---|
772 | return _heap->top(); |
---|
773 | } |
---|
774 | |
---|
775 | ///Runs the algorithm from the given node. |
---|
776 | |
---|
777 | ///This method runs the %Dijkstra algorithm from node \c s |
---|
778 | ///in order to compute the shortest path to each node. |
---|
779 | /// |
---|
780 | ///The algorithm computes |
---|
781 | ///- the shortest path tree, |
---|
782 | ///- the distance of each node from the root. |
---|
783 | /// |
---|
784 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
785 | ///\code |
---|
786 | /// d.init(); |
---|
787 | /// d.addSource(s); |
---|
788 | /// d.start(); |
---|
789 | ///\endcode |
---|
790 | void run(Node s) { |
---|
791 | init(); |
---|
792 | addSource(s); |
---|
793 | start(); |
---|
794 | } |
---|
795 | |
---|
796 | ///Finds the shortest path between \c s and \c t. |
---|
797 | |
---|
798 | ///This method runs the %Dijkstra algorithm from node \c s |
---|
799 | ///in order to compute the shortest path to \c t. |
---|
800 | /// |
---|
801 | ///\return The length of the shortest <tt>s</tt>--<tt>t</tt> path, |
---|
802 | ///if \c t is reachable form \c s, \c 0 otherwise. |
---|
803 | /// |
---|
804 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is just a |
---|
805 | ///shortcut of the following code. |
---|
806 | ///\code |
---|
807 | /// d.init(); |
---|
808 | /// d.addSource(s); |
---|
809 | /// d.start(t); |
---|
810 | ///\endcode |
---|
811 | Value run(Node s,Node t) { |
---|
812 | init(); |
---|
813 | addSource(s); |
---|
814 | start(t); |
---|
815 | return (*_pred)[t]==INVALID?OperationTraits::zero():(*_dist)[t]; |
---|
816 | } |
---|
817 | |
---|
818 | ///@} |
---|
819 | |
---|
820 | ///\name Query Functions |
---|
821 | ///The result of the %Dijkstra algorithm can be obtained using these |
---|
822 | ///functions.\n |
---|
823 | ///Either \ref lemon::Dijkstra::run() "run()" or |
---|
824 | ///\ref lemon::Dijkstra::start() "start()" must be called before |
---|
825 | ///using them. |
---|
826 | |
---|
827 | ///@{ |
---|
828 | |
---|
829 | ///The shortest path to a node. |
---|
830 | |
---|
831 | ///Returns the shortest path to a node. |
---|
832 | /// |
---|
833 | ///\warning \c t should be reachable from the root(s). |
---|
834 | /// |
---|
835 | ///\pre Either \ref run() or \ref start() must be called before |
---|
836 | ///using this function. |
---|
837 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
838 | |
---|
839 | ///The distance of a node from the root(s). |
---|
840 | |
---|
841 | ///Returns the distance of a node from the root(s). |
---|
842 | /// |
---|
843 | ///\warning If node \c v is not reachable from the root(s), then |
---|
844 | ///the return value of this function is undefined. |
---|
845 | /// |
---|
846 | ///\pre Either \ref run() or \ref start() must be called before |
---|
847 | ///using this function. |
---|
848 | Value dist(Node v) const { return (*_dist)[v]; } |
---|
849 | |
---|
850 | ///Returns the 'previous arc' of the shortest path tree for a node. |
---|
851 | |
---|
852 | ///This function returns the 'previous arc' of the shortest path |
---|
853 | ///tree for the node \c v, i.e. it returns the last arc of a |
---|
854 | ///shortest path from the root(s) to \c v. It is \c INVALID if \c v |
---|
855 | ///is not reachable from the root(s) or if \c v is a root. |
---|
856 | /// |
---|
857 | ///The shortest path tree used here is equal to the shortest path |
---|
858 | ///tree used in \ref predNode(). |
---|
859 | /// |
---|
860 | ///\pre Either \ref run() or \ref start() must be called before |
---|
861 | ///using this function. |
---|
862 | Arc predArc(Node v) const { return (*_pred)[v]; } |
---|
863 | |
---|
864 | ///Returns the 'previous node' of the shortest path tree for a node. |
---|
865 | |
---|
866 | ///This function returns the 'previous node' of the shortest path |
---|
867 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
868 | ///from a shortest path from the root(s) to \c v. It is \c INVALID |
---|
869 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
870 | /// |
---|
871 | ///The shortest path tree used here is equal to the shortest path |
---|
872 | ///tree used in \ref predArc(). |
---|
873 | /// |
---|
874 | ///\pre Either \ref run() or \ref start() must be called before |
---|
875 | ///using this function. |
---|
876 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
877 | G->source((*_pred)[v]); } |
---|
878 | |
---|
879 | ///\brief Returns a const reference to the node map that stores the |
---|
880 | ///distances of the nodes. |
---|
881 | /// |
---|
882 | ///Returns a const reference to the node map that stores the distances |
---|
883 | ///of the nodes calculated by the algorithm. |
---|
884 | /// |
---|
885 | ///\pre Either \ref run() or \ref init() |
---|
886 | ///must be called before using this function. |
---|
887 | const DistMap &distMap() const { return *_dist;} |
---|
888 | |
---|
889 | ///\brief Returns a const reference to the node map that stores the |
---|
890 | ///predecessor arcs. |
---|
891 | /// |
---|
892 | ///Returns a const reference to the node map that stores the predecessor |
---|
893 | ///arcs, which form the shortest path tree. |
---|
894 | /// |
---|
895 | ///\pre Either \ref run() or \ref init() |
---|
896 | ///must be called before using this function. |
---|
897 | const PredMap &predMap() const { return *_pred;} |
---|
898 | |
---|
899 | ///Checks if a node is reachable from the root(s). |
---|
900 | |
---|
901 | ///Returns \c true if \c v is reachable from the root(s). |
---|
902 | ///\pre Either \ref run() or \ref start() |
---|
903 | ///must be called before using this function. |
---|
904 | bool reached(Node v) const { return (*_heap_cross_ref)[v] != |
---|
905 | Heap::PRE_HEAP; } |
---|
906 | |
---|
907 | ///Checks if a node is processed. |
---|
908 | |
---|
909 | ///Returns \c true if \c v is processed, i.e. the shortest |
---|
910 | ///path to \c v has already found. |
---|
911 | ///\pre Either \ref run() or \ref start() |
---|
912 | ///must be called before using this function. |
---|
913 | bool processed(Node v) const { return (*_heap_cross_ref)[v] == |
---|
914 | Heap::POST_HEAP; } |
---|
915 | |
---|
916 | ///The current distance of a node from the root(s). |
---|
917 | |
---|
918 | ///Returns the current distance of a node from the root(s). |
---|
919 | ///It may be decreased in the following processes. |
---|
920 | ///\pre \c v should be reached but not processed. |
---|
921 | Value currentDist(Node v) const { return (*_heap)[v]; } |
---|
922 | |
---|
923 | ///@} |
---|
924 | }; |
---|
925 | |
---|
926 | |
---|
927 | ///Default traits class of dijkstra() function. |
---|
928 | |
---|
929 | ///Default traits class of dijkstra() function. |
---|
930 | ///\tparam GR The type of the digraph. |
---|
931 | ///\tparam LM The type of the length map. |
---|
932 | template<class GR, class LM> |
---|
933 | struct DijkstraWizardDefaultTraits |
---|
934 | { |
---|
935 | ///The type of the digraph the algorithm runs on. |
---|
936 | typedef GR Digraph; |
---|
937 | ///The type of the map that stores the arc lengths. |
---|
938 | |
---|
939 | ///The type of the map that stores the arc lengths. |
---|
940 | ///It must meet the \ref concepts::ReadMap "ReadMap" concept. |
---|
941 | typedef LM LengthMap; |
---|
942 | ///The type of the length of the arcs. |
---|
943 | typedef typename LM::Value Value; |
---|
944 | |
---|
945 | /// Operation traits for Dijkstra algorithm. |
---|
946 | |
---|
947 | /// This class defines the operations that are used in the algorithm. |
---|
948 | /// \see DijkstraDefaultOperationTraits |
---|
949 | typedef DijkstraDefaultOperationTraits<Value> OperationTraits; |
---|
950 | |
---|
951 | /// The cross reference type used by the heap. |
---|
952 | |
---|
953 | /// The cross reference type used by the heap. |
---|
954 | /// Usually it is \c Digraph::NodeMap<int>. |
---|
955 | typedef typename Digraph::template NodeMap<int> HeapCrossRef; |
---|
956 | ///Instantiates a \ref HeapCrossRef. |
---|
957 | |
---|
958 | ///This function instantiates a \ref HeapCrossRef. |
---|
959 | /// \param g is the digraph, to which we would like to define the |
---|
960 | /// HeapCrossRef. |
---|
961 | /// \todo The digraph alone may be insufficient for the initialization |
---|
962 | static HeapCrossRef *createHeapCrossRef(const Digraph &g) |
---|
963 | { |
---|
964 | return new HeapCrossRef(g); |
---|
965 | } |
---|
966 | |
---|
967 | ///The heap type used by the Dijkstra algorithm. |
---|
968 | |
---|
969 | ///The heap type used by the Dijkstra algorithm. |
---|
970 | /// |
---|
971 | ///\sa BinHeap |
---|
972 | ///\sa Dijkstra |
---|
973 | typedef BinHeap<Value, typename Digraph::template NodeMap<int>, |
---|
974 | std::less<Value> > Heap; |
---|
975 | |
---|
976 | ///Instantiates a \ref Heap. |
---|
977 | |
---|
978 | ///This function instantiates a \ref Heap. |
---|
979 | /// \param r is the HeapCrossRef which is used. |
---|
980 | static Heap *createHeap(HeapCrossRef& r) |
---|
981 | { |
---|
982 | return new Heap(r); |
---|
983 | } |
---|
984 | |
---|
985 | ///\brief The type of the map that stores the predecessor |
---|
986 | ///arcs of the shortest paths. |
---|
987 | /// |
---|
988 | ///The type of the map that stores the predecessor |
---|
989 | ///arcs of the shortest paths. |
---|
990 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
991 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
992 | ///Instantiates a \ref PredMap. |
---|
993 | |
---|
994 | ///This function instantiates a \ref PredMap. |
---|
995 | ///\param g is the digraph, to which we would like to define the |
---|
996 | ///\ref PredMap. |
---|
997 | ///\todo The digraph alone may be insufficient to initialize |
---|
998 | static PredMap *createPredMap(const Digraph &g) |
---|
999 | { |
---|
1000 | return new PredMap(g); |
---|
1001 | } |
---|
1002 | |
---|
1003 | ///The type of the map that indicates which nodes are processed. |
---|
1004 | |
---|
1005 | ///The type of the map that indicates which nodes are processed. |
---|
1006 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
1007 | ///By default it is a NullMap. |
---|
1008 | ///\todo If it is set to a real map, |
---|
1009 | ///Dijkstra::processed() should read this. |
---|
1010 | ///\todo named parameter to set this type, function to read and write. |
---|
1011 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
1012 | ///Instantiates a \ref ProcessedMap. |
---|
1013 | |
---|
1014 | ///This function instantiates a \ref ProcessedMap. |
---|
1015 | ///\param g is the digraph, to which |
---|
1016 | ///we would like to define the \ref ProcessedMap. |
---|
1017 | #ifdef DOXYGEN |
---|
1018 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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1019 | #else |
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1020 | static ProcessedMap *createProcessedMap(const Digraph &) |
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1021 | #endif |
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1022 | { |
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1023 | return new ProcessedMap(); |
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1024 | } |
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1025 | |
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1026 | ///The type of the map that stores the distances of the nodes. |
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1027 | |
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1028 | ///The type of the map that stores the distances of the nodes. |
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1029 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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1030 | typedef typename Digraph::template NodeMap<typename LM::Value> DistMap; |
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1031 | ///Instantiates a \ref DistMap. |
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1032 | |
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1033 | ///This function instantiates a \ref DistMap. |
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1034 | ///\param g is the digraph, to which we would like to define |
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1035 | ///the \ref DistMap |
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1036 | static DistMap *createDistMap(const Digraph &g) |
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1037 | { |
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1038 | return new DistMap(g); |
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1039 | } |
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1040 | |
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1041 | ///The type of the shortest paths. |
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1042 | |
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1043 | ///The type of the shortest paths. |
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1044 | ///It must meet the \ref concepts::Path "Path" concept. |
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1045 | typedef lemon::Path<Digraph> Path; |
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1046 | }; |
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1047 | |
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1048 | /// Default traits class used by \ref DijkstraWizard |
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1049 | |
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1050 | /// To make it easier to use Dijkstra algorithm |
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1051 | /// we have created a wizard class. |
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1052 | /// This \ref DijkstraWizard class needs default traits, |
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1053 | /// as well as the \ref Dijkstra class. |
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1054 | /// The \ref DijkstraWizardBase is a class to be the default traits of the |
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1055 | /// \ref DijkstraWizard class. |
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1056 | /// \todo More named parameters are required... |
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1057 | template<class GR,class LM> |
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1058 | class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM> |
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1059 | { |
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1060 | typedef DijkstraWizardDefaultTraits<GR,LM> Base; |
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1061 | protected: |
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1062 | //The type of the nodes in the digraph. |
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1063 | typedef typename Base::Digraph::Node Node; |
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1064 | |
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1065 | //Pointer to the digraph the algorithm runs on. |
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1066 | void *_g; |
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1067 | //Pointer to the length map. |
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1068 | void *_length; |
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1069 | //Pointer to the map of processed nodes. |
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1070 | void *_processed; |
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1071 | //Pointer to the map of predecessors arcs. |
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1072 | void *_pred; |
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1073 | //Pointer to the map of distances. |
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1074 | void *_dist; |
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1075 | //Pointer to the shortest path to the target node. |
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1076 | void *_path; |
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1077 | //Pointer to the distance of the target node. |
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1078 | void *_di; |
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1079 | |
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1080 | public: |
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1081 | /// Constructor. |
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1082 | |
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1083 | /// This constructor does not require parameters, therefore it initiates |
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1084 | /// all of the attributes to \c 0. |
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1085 | DijkstraWizardBase() : _g(0), _length(0), _processed(0), _pred(0), |
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1086 | _dist(0), _path(0), _di(0) {} |
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1087 | |
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1088 | /// Constructor. |
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1089 | |
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1090 | /// This constructor requires two parameters, |
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1091 | /// others are initiated to \c 0. |
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1092 | /// \param g The digraph the algorithm runs on. |
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1093 | /// \param l The length map. |
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1094 | DijkstraWizardBase(const GR &g,const LM &l) : |
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1095 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
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1096 | _length(reinterpret_cast<void*>(const_cast<LM*>(&l))), |
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1097 | _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
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1098 | |
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1099 | }; |
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1100 | |
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1101 | /// Auxiliary class for the function-type interface of Dijkstra algorithm. |
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1102 | |
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1103 | /// This auxiliary class is created to implement the |
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1104 | /// \ref dijkstra() "function-type interface" of \ref Dijkstra algorithm. |
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1105 | /// It does not have own \ref run() method, it uses the functions |
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1106 | /// and features of the plain \ref Dijkstra. |
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1107 | /// |
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1108 | /// This class should only be used through the \ref dijkstra() function, |
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1109 | /// which makes it easier to use the algorithm. |
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1110 | template<class TR> |
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1111 | class DijkstraWizard : public TR |
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1112 | { |
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1113 | typedef TR Base; |
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1114 | |
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1115 | ///The type of the digraph the algorithm runs on. |
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1116 | typedef typename TR::Digraph Digraph; |
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1117 | |
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1118 | typedef typename Digraph::Node Node; |
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1119 | typedef typename Digraph::NodeIt NodeIt; |
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1120 | typedef typename Digraph::Arc Arc; |
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1121 | typedef typename Digraph::OutArcIt OutArcIt; |
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1122 | |
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1123 | ///The type of the map that stores the arc lengths. |
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1124 | typedef typename TR::LengthMap LengthMap; |
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1125 | ///The type of the length of the arcs. |
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1126 | typedef typename LengthMap::Value Value; |
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1127 | ///\brief The type of the map that stores the predecessor |
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1128 | ///arcs of the shortest paths. |
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1129 | typedef typename TR::PredMap PredMap; |
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1130 | ///The type of the map that stores the distances of the nodes. |
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1131 | typedef typename TR::DistMap DistMap; |
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1132 | ///The type of the map that indicates which nodes are processed. |
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1133 | typedef typename TR::ProcessedMap ProcessedMap; |
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1134 | ///The type of the shortest paths |
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1135 | typedef typename TR::Path Path; |
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1136 | ///The heap type used by the dijkstra algorithm. |
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1137 | typedef typename TR::Heap Heap; |
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1138 | |
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1139 | public: |
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1140 | |
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1141 | /// Constructor. |
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1142 | DijkstraWizard() : TR() {} |
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1143 | |
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1144 | /// Constructor that requires parameters. |
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1145 | |
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1146 | /// Constructor that requires parameters. |
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1147 | /// These parameters will be the default values for the traits class. |
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1148 | /// \param g The digraph the algorithm runs on. |
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1149 | /// \param l The length map. |
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1150 | DijkstraWizard(const Digraph &g, const LengthMap &l) : |
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1151 | TR(g,l) {} |
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1152 | |
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1153 | ///Copy constructor |
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1154 | DijkstraWizard(const TR &b) : TR(b) {} |
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1155 | |
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1156 | ~DijkstraWizard() {} |
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1157 | |
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1158 | ///Runs Dijkstra algorithm from the given source node. |
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1159 | |
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1160 | ///This method runs %Dijkstra algorithm from the given source node |
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1161 | ///in order to compute the shortest path to each node. |
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1162 | void run(Node s) |
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1163 | { |
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1164 | if (s==INVALID) throw UninitializedParameter(); |
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1165 | Dijkstra<Digraph,LengthMap,TR> |
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1166 | dijk(*reinterpret_cast<const Digraph*>(Base::_g), |
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1167 | *reinterpret_cast<const LengthMap*>(Base::_length)); |
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1168 | if (Base::_pred) |
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1169 | dijk.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
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1170 | if (Base::_dist) |
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1171 | dijk.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
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1172 | if (Base::_processed) |
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1173 | dijk.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
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1174 | dijk.run(s); |
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1175 | } |
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1176 | |
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1177 | ///Finds the shortest path between \c s and \c t. |
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1178 | |
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1179 | ///This method runs the %Dijkstra algorithm from node \c s |
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1180 | ///in order to compute the shortest path to node \c t |
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1181 | ///(it stops searching when \c t is processed). |
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1182 | /// |
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1183 | ///\return \c true if \c t is reachable form \c s. |
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1184 | bool run(Node s, Node t) |
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1185 | { |
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1186 | if (s==INVALID || t==INVALID) throw UninitializedParameter(); |
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1187 | Dijkstra<Digraph,LengthMap,TR> |
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1188 | dijk(*reinterpret_cast<const Digraph*>(Base::_g), |
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1189 | *reinterpret_cast<const LengthMap*>(Base::_length)); |
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1190 | if (Base::_pred) |
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1191 | dijk.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
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1192 | if (Base::_dist) |
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1193 | dijk.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
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1194 | if (Base::_processed) |
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1195 | dijk.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
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1196 | dijk.run(s,t); |
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1197 | if (Base::_path) |
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1198 | *reinterpret_cast<Path*>(Base::_path) = dijk.path(t); |
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1199 | if (Base::_di) |
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1200 | *reinterpret_cast<Value*>(Base::_di) = dijk.dist(t); |
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1201 | return dijk.reached(t); |
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1202 | } |
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1203 | |
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1204 | template<class T> |
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1205 | struct SetPredMapBase : public Base { |
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1206 | typedef T PredMap; |
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1207 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
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1208 | SetPredMapBase(const TR &b) : TR(b) {} |
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1209 | }; |
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1210 | ///\brief \ref named-func-param "Named parameter" |
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1211 | ///for setting \ref PredMap object. |
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1212 | /// |
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1213 | ///\ref named-func-param "Named parameter" |
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1214 | ///for setting \ref PredMap object. |
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1215 | template<class T> |
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1216 | DijkstraWizard<SetPredMapBase<T> > predMap(const T &t) |
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1217 | { |
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1218 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
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1219 | return DijkstraWizard<SetPredMapBase<T> >(*this); |
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1220 | } |
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1221 | |
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1222 | template<class T> |
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1223 | struct SetDistMapBase : public Base { |
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1224 | typedef T DistMap; |
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1225 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
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1226 | SetDistMapBase(const TR &b) : TR(b) {} |
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1227 | }; |
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1228 | ///\brief \ref named-func-param "Named parameter" |
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1229 | ///for setting \ref DistMap object. |
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1230 | /// |
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1231 | ///\ref named-func-param "Named parameter" |
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1232 | ///for setting \ref DistMap object. |
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1233 | template<class T> |
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1234 | DijkstraWizard<SetDistMapBase<T> > distMap(const T &t) |
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1235 | { |
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1236 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
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1237 | return DijkstraWizard<SetDistMapBase<T> >(*this); |
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1238 | } |
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1239 | |
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1240 | template<class T> |
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1241 | struct SetProcessedMapBase : public Base { |
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1242 | typedef T ProcessedMap; |
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1243 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
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1244 | SetProcessedMapBase(const TR &b) : TR(b) {} |
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1245 | }; |
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1246 | ///\brief \ref named-func-param "Named parameter" |
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1247 | ///for setting \ref ProcessedMap object. |
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1248 | /// |
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1249 | /// \ref named-func-param "Named parameter" |
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1250 | ///for setting \ref ProcessedMap object. |
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1251 | template<class T> |
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1252 | DijkstraWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
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1253 | { |
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1254 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
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1255 | return DijkstraWizard<SetProcessedMapBase<T> >(*this); |
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1256 | } |
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1257 | |
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1258 | template<class T> |
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1259 | struct SetPathBase : public Base { |
---|
1260 | typedef T Path; |
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1261 | SetPathBase(const TR &b) : TR(b) {} |
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1262 | }; |
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1263 | ///\brief \ref named-func-param "Named parameter" |
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1264 | ///for getting the shortest path to the target node. |
---|
1265 | /// |
---|
1266 | ///\ref named-func-param "Named parameter" |
---|
1267 | ///for getting the shortest path to the target node. |
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1268 | template<class T> |
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1269 | DijkstraWizard<SetPathBase<T> > path(const T &t) |
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1270 | { |
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1271 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
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1272 | return DijkstraWizard<SetPathBase<T> >(*this); |
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1273 | } |
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1274 | |
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1275 | ///\brief \ref named-func-param "Named parameter" |
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1276 | ///for getting the distance of the target node. |
---|
1277 | /// |
---|
1278 | ///\ref named-func-param "Named parameter" |
---|
1279 | ///for getting the distance of the target node. |
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1280 | DijkstraWizard dist(const Value &d) |
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1281 | { |
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1282 | Base::_di=reinterpret_cast<void*>(const_cast<Value*>(&d)); |
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1283 | return *this; |
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1284 | } |
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1285 | |
---|
1286 | }; |
---|
1287 | |
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1288 | ///Function-type interface for Dijkstra algorithm. |
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1289 | |
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1290 | /// \ingroup shortest_path |
---|
1291 | ///Function-type interface for Dijkstra algorithm. |
---|
1292 | /// |
---|
1293 | ///This function also has several \ref named-func-param "named parameters", |
---|
1294 | ///they are declared as the members of class \ref DijkstraWizard. |
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1295 | ///The following examples show how to use these parameters. |
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1296 | ///\code |
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1297 | /// // Compute shortest path from node s to each node |
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1298 | /// dijkstra(g,length).predMap(preds).distMap(dists).run(s); |
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1299 | /// |
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1300 | /// // Compute shortest path from s to t |
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1301 | /// bool reached = dijkstra(g,length).path(p).dist(d).run(s,t); |
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1302 | ///\endcode |
---|
1303 | ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()" |
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1304 | ///to the end of the parameter list. |
---|
1305 | ///\sa DijkstraWizard |
---|
1306 | ///\sa Dijkstra |
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1307 | template<class GR, class LM> |
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1308 | DijkstraWizard<DijkstraWizardBase<GR,LM> > |
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1309 | dijkstra(const GR &digraph, const LM &length) |
---|
1310 | { |
---|
1311 | return DijkstraWizard<DijkstraWizardBase<GR,LM> >(digraph,length); |
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1312 | } |
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1313 | |
---|
1314 | } //END OF NAMESPACE LEMON |
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1315 | |
---|
1316 | #endif |
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