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 HYPERCUBE_GRAPH_H |
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20 | #define HYPERCUBE_GRAPH_H |
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21 | |
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22 | #include <iostream> |
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23 | #include <vector> |
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24 | #include <lemon/core.h> |
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25 | #include <lemon/error.h> |
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26 | |
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27 | #include <lemon/bits/base_extender.h> |
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28 | #include <lemon/bits/graph_extender.h> |
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29 | |
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30 | ///\ingroup graphs |
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31 | ///\file |
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32 | ///\brief HypercubeDigraph class. |
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33 | |
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34 | namespace lemon { |
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35 | |
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36 | class HypercubeDigraphBase { |
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37 | |
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38 | public: |
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39 | |
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40 | typedef HypercubeDigraphBase Digraph; |
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41 | |
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42 | class Node; |
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43 | class Arc; |
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44 | |
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45 | public: |
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46 | |
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47 | HypercubeDigraphBase() {} |
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48 | |
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49 | protected: |
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50 | |
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51 | void construct(int dim) { |
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52 | _dim = dim; |
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53 | _nodeNum = 1 << dim; |
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54 | } |
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55 | |
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56 | public: |
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57 | |
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58 | typedef True NodeNumTag; |
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59 | typedef True ArcNumTag; |
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60 | |
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61 | int nodeNum() const { return _nodeNum; } |
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62 | int arcNum() const { return _nodeNum * _dim; } |
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63 | |
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64 | int maxNodeId() const { return nodeNum() - 1; } |
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65 | int maxArcId() const { return arcNum() - 1; } |
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66 | |
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67 | Node source(Arc e) const { |
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68 | return e.id / _dim; |
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69 | } |
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70 | |
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71 | Node target(Arc e) const { |
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72 | return (e.id / _dim) ^ (1 << (e.id % _dim)); |
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73 | } |
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74 | |
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75 | static int id(Node v) { return v.id; } |
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76 | static int id(Arc e) { return e.id; } |
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77 | |
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78 | static Node nodeFromId(int id) { return Node(id); } |
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79 | |
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80 | static Arc arcFromId(int id) { return Arc(id); } |
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81 | |
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82 | class Node { |
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83 | friend class HypercubeDigraphBase; |
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84 | protected: |
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85 | int id; |
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86 | Node(int _id) { id = _id;} |
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87 | public: |
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88 | Node() {} |
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89 | Node (Invalid) { id = -1; } |
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90 | bool operator==(const Node node) const { return id == node.id; } |
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91 | bool operator!=(const Node node) const { return id != node.id; } |
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92 | bool operator<(const Node node) const { return id < node.id; } |
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93 | }; |
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94 | |
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95 | class Arc { |
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96 | friend class HypercubeDigraphBase; |
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97 | protected: |
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98 | int id; |
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99 | Arc(int _id) : id(_id) {} |
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100 | public: |
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101 | Arc() { } |
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102 | Arc (Invalid) { id = -1; } |
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103 | bool operator==(const Arc arc) const { return id == arc.id; } |
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104 | bool operator!=(const Arc arc) const { return id != arc.id; } |
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105 | bool operator<(const Arc arc) const { return id < arc.id; } |
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106 | }; |
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107 | |
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108 | void first(Node& node) const { |
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109 | node.id = nodeNum() - 1; |
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110 | } |
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111 | |
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112 | static void next(Node& node) { |
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113 | --node.id; |
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114 | } |
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115 | |
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116 | void first(Arc& arc) const { |
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117 | arc.id = arcNum() - 1; |
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118 | } |
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119 | |
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120 | static void next(Arc& arc) { |
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121 | --arc.id; |
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122 | } |
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123 | |
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124 | void firstOut(Arc& arc, const Node& node) const { |
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125 | arc.id = node.id * _dim; |
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126 | } |
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127 | |
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128 | void nextOut(Arc& arc) const { |
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129 | ++arc.id; |
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130 | if (arc.id % _dim == 0) arc.id = -1; |
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131 | } |
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132 | |
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133 | void firstIn(Arc& arc, const Node& node) const { |
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134 | arc.id = (node.id ^ 1) * _dim; |
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135 | } |
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136 | |
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137 | void nextIn(Arc& arc) const { |
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138 | int cnt = arc.id % _dim; |
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139 | if ((cnt + 1) % _dim == 0) { |
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140 | arc.id = -1; |
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141 | } else { |
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142 | arc.id = ((arc.id / _dim) ^ ((1 << cnt) * 3)) * _dim + cnt + 1; |
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143 | } |
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144 | } |
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145 | |
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146 | int dimension() const { |
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147 | return _dim; |
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148 | } |
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149 | |
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150 | bool projection(Node node, int n) const { |
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151 | return static_cast<bool>(node.id & (1 << n)); |
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152 | } |
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153 | |
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154 | int dimension(Arc arc) const { |
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155 | return arc.id % _dim; |
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156 | } |
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157 | |
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158 | int index(Node node) const { |
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159 | return node.id; |
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160 | } |
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161 | |
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162 | Node operator()(int ix) const { |
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163 | return Node(ix); |
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164 | } |
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165 | |
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166 | private: |
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167 | int _dim, _nodeNum; |
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168 | }; |
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169 | |
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170 | |
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171 | typedef DigraphExtender<HypercubeDigraphBase> ExtendedHypercubeDigraphBase; |
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172 | |
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173 | /// \ingroup digraphs |
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174 | /// |
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175 | /// \brief Hypercube digraph class |
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176 | /// |
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177 | /// This class implements a special digraph type. The nodes of the |
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178 | /// digraph are indiced with integers with at most \c dim binary digits. |
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179 | /// Two nodes are connected in the digraph if the indices differ only |
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180 | /// on one position in the binary form. |
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181 | /// |
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182 | /// \note The type of the \c ids is chosen to \c int because efficiency |
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183 | /// reasons. Thus the maximum dimension of this implementation is 26. |
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184 | /// |
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185 | /// The digraph type is fully conform to the \ref concepts::Digraph |
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186 | /// concept but it does not conform to \ref concepts::Graph. |
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187 | class HypercubeDigraph : public ExtendedHypercubeDigraphBase { |
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188 | public: |
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189 | |
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190 | typedef ExtendedHypercubeDigraphBase Parent; |
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191 | |
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192 | /// \brief Construct a hypercube digraph with \c dim dimension. |
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193 | /// |
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194 | /// Construct a hypercube digraph with \c dim dimension. |
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195 | HypercubeDigraph(int dim) { construct(dim); } |
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196 | |
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197 | /// \brief Gives back the number of the dimensions. |
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198 | /// |
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199 | /// Gives back the number of the dimensions. |
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200 | int dimension() const { |
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201 | return Parent::dimension(); |
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202 | } |
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203 | |
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204 | /// \brief Returns true if the n'th bit of the node is one. |
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205 | /// |
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206 | /// Returns true if the n'th bit of the node is one. |
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207 | bool projection(Node node, int n) const { |
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208 | return Parent::projection(node, n); |
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209 | } |
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210 | |
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211 | /// \brief The dimension id of the arc. |
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212 | /// |
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213 | /// It returns the dimension id of the arc. It can |
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214 | /// be in the \f$ \{0, 1, \dots, dim-1\} \f$ interval. |
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215 | int dimension(Arc arc) const { |
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216 | return Parent::dimension(arc); |
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217 | } |
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218 | |
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219 | /// \brief Gives back the index of the node. |
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220 | /// |
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221 | /// Gives back the index of the node. The lower bits of the |
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222 | /// integer describes the node. |
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223 | int index(Node node) const { |
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224 | return Parent::index(node); |
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225 | } |
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226 | |
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227 | /// \brief Gives back the node by its index. |
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228 | /// |
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229 | /// Gives back the node by its index. |
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230 | Node operator()(int ix) const { |
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231 | return Parent::operator()(ix); |
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232 | } |
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233 | |
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234 | /// \brief Number of nodes. |
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235 | int nodeNum() const { return Parent::nodeNum(); } |
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236 | /// \brief Number of arcs. |
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237 | int arcNum() const { return Parent::arcNum(); } |
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238 | |
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239 | /// \brief Linear combination map. |
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240 | /// |
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241 | /// It makes possible to give back a linear combination |
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242 | /// for each node. This function works like the \c std::accumulate |
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243 | /// so it accumulates the \c bf binary function with the \c fv |
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244 | /// first value. The map accumulates only on that dimensions where |
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245 | /// the node's index is one. The accumulated values should be |
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246 | /// given by the \c begin and \c end iterators and the length of this |
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247 | /// range should be equal to the dimension number of the digraph. |
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248 | /// |
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249 | ///\code |
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250 | /// const int DIM = 3; |
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251 | /// HypercubeDigraph digraph(DIM); |
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252 | /// dim2::Point<double> base[DIM]; |
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253 | /// for (int k = 0; k < DIM; ++k) { |
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254 | /// base[k].x = rnd(); |
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255 | /// base[k].y = rnd(); |
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256 | /// } |
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257 | /// HypercubeDigraph::HyperMap<dim2::Point<double> > |
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258 | /// pos(digraph, base, base + DIM, dim2::Point<double>(0.0, 0.0)); |
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259 | ///\endcode |
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260 | /// |
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261 | /// \see HypercubeDigraph |
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262 | template <typename T, typename BF = std::plus<T> > |
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263 | class HyperMap { |
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264 | public: |
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265 | |
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266 | typedef Node Key; |
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267 | typedef T Value; |
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268 | |
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269 | |
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270 | /// \brief Constructor for HyperMap. |
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271 | /// |
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272 | /// Construct a HyperMap for the given digraph. The accumulated values |
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273 | /// should be given by the \c begin and \c end iterators and the length |
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274 | /// of this range should be equal to the dimension number of the digraph. |
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275 | /// |
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276 | /// This function accumulates the \c bf binary function with |
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277 | /// the \c fv first value. The map accumulates only on that dimensions |
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278 | /// where the node's index is one. |
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279 | template <typename It> |
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280 | HyperMap(const Digraph& digraph, It begin, It end, |
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281 | T fv = 0.0, const BF& bf = BF()) |
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282 | : _graph(digraph), _values(begin, end), _first_value(fv), _bin_func(bf) |
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283 | { |
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284 | LEMON_ASSERT(_values.size() == digraph.dimension(), |
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285 | "Wrong size of dimension"); |
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286 | } |
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287 | |
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288 | /// \brief Gives back the partial accumulated value. |
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289 | /// |
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290 | /// Gives back the partial accumulated value. |
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291 | Value operator[](Key k) const { |
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292 | Value val = _first_value; |
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293 | int id = _graph.index(k); |
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294 | int n = 0; |
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295 | while (id != 0) { |
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296 | if (id & 1) { |
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297 | val = _bin_func(val, _values[n]); |
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298 | } |
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299 | id >>= 1; |
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300 | ++n; |
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301 | } |
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302 | return val; |
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303 | } |
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304 | |
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305 | private: |
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306 | const Digraph& _graph; |
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307 | std::vector<T> _values; |
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308 | T _first_value; |
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309 | BF _bin_func; |
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310 | }; |
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311 | |
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312 | }; |
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313 | |
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314 | } |
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315 | |
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316 | #endif |
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