1 | /* -*- C++ -*- |
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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 | /// \ingroup demos |
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20 | /// \file |
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21 | /// \brief Using descriptor map and own special map types. |
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22 | /// |
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23 | /// This demo shows how can be used the DescriptorMap class |
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24 | /// which helps to use unique label for each node or edge. |
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25 | /// And it gives an example how easy is creating own map types. |
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26 | /// |
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27 | /// \include descriptor_map_demo.cc |
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28 | |
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29 | #include <lemon/list_graph.h> |
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30 | #include <lemon/graph_utils.h> |
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31 | #include <lemon/graph_writer.h> |
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32 | #include <lemon/dim2.h> |
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33 | #include <lemon/graph_to_eps.h> |
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34 | |
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35 | #include <lemon/random.h> |
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36 | |
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37 | #include <iostream> |
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38 | |
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39 | #include <cmath> |
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40 | |
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41 | |
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42 | using namespace lemon; |
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43 | |
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44 | // Special dim2::Point<double> map type |
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45 | // |
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46 | // It gives back a position for each node. The position of the nodes |
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47 | // are on the circle with the given center and radius. |
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48 | // |
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49 | // Because we use the descriptor map it will hold the proprty |
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50 | // described above even if a node added or deleted. |
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51 | template <typename Graph> |
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52 | class CircleMap { |
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53 | public: |
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54 | |
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55 | typedef dim2::Point<double> Value; |
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56 | typedef typename Graph::Node Key; |
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57 | |
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58 | CircleMap(const Graph& _graph, |
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59 | const Value& _center = Value(0.0, 0.0), |
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60 | double _radius = 1.0) |
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61 | : descriptor(_graph), center(_center), radius(_radius) {} |
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62 | |
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63 | Value operator[](const Key& key) const { |
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64 | double angle = descriptor[key] * 2 * M_PI |
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65 | / double(descriptor.inverse().size()); |
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66 | double x = std::cos(angle) * radius + center.x; |
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67 | double y = std::sin(angle) * radius + center.y; |
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68 | return Value(x, y); |
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69 | } |
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70 | |
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71 | private: |
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72 | |
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73 | DescriptorMap<Graph, typename Graph::Node> descriptor; |
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74 | Value center; |
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75 | double radius; |
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76 | }; |
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77 | |
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78 | int main() { |
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79 | typedef ListGraph Graph; |
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80 | typedef Graph::Node Node; |
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81 | typedef Graph::Edge Edge; |
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82 | |
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83 | // Generating a graph |
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84 | |
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85 | std::cout << "Generating graph: " << std::endl; |
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86 | |
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87 | Graph graph; |
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88 | |
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89 | const int NODE = 16; |
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90 | for (int i = 0; i < NODE; ++i) { |
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91 | graph.addNode(); |
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92 | } |
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93 | |
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94 | // Creating descriptor map and inverse |
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95 | DescriptorMap<Graph, Node> nodeDesc(graph); |
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96 | DescriptorMap<Graph, Node>::InverseMap nodeInv(nodeDesc); |
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97 | |
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98 | // Adding edges |
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99 | // The descriptor map always maps an integer value for each node. |
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100 | // The range of the values is always [0..n - 1] where n is the |
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101 | // number of the nodes of the graph. The inverse map gives back the |
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102 | // the node by its descriptor value. |
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103 | // |
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104 | // The inversemap cannot works without its DescriptorMap because |
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105 | // it holds reference to it. |
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106 | const int EDGE = int(NODE * std::log(double(NODE))); |
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107 | for (int i = 0; i < EDGE; ++i) { |
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108 | int si = rnd[NODE]; |
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109 | int ti = rnd[NODE]; |
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110 | |
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111 | graph.addEdge(nodeInv[si], nodeInv[ti]); |
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112 | } |
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113 | |
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114 | GraphWriter<Graph>(std::cout, graph).run(); |
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115 | |
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116 | std::cout << std::endl; |
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117 | std::cout << "Postscript file: descriptor_map_demo.eps" << std::endl; |
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118 | |
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119 | // Make postscript from the graph. |
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120 | |
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121 | CircleMap<Graph> coords(graph, dim2::Point<double>(0.0, 0.0), 10.0); |
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122 | |
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123 | graphToEps(graph,"descriptor_map_demo.eps").scaleToA4(). |
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124 | title("Generated graph"). |
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125 | copyright("(C) 2003-2007 LEMON Project"). |
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126 | coords(coords). |
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127 | nodeScale(1.0). |
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128 | enableParallel().parEdgeDist(1). |
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129 | drawArrows().arrowWidth(1).arrowLength(1). |
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130 | run(); |
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131 | |
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132 | return 0; |
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133 | } |
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