1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library. |
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4 | * |
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5 | * Copyright (C) 2003-2009 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #include <lemon/concepts/digraph.h> |
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20 | #include <lemon/smart_graph.h> |
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21 | #include <lemon/list_graph.h> |
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22 | #include <lemon/lgf_reader.h> |
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23 | #include <lemon/bellman_ford.h> |
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24 | #include <lemon/path.h> |
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25 | |
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26 | #include "graph_test.h" |
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27 | #include "test_tools.h" |
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28 | |
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29 | using namespace lemon; |
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30 | |
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31 | char test_lgf[] = |
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32 | "@nodes\n" |
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33 | "label\n" |
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34 | "0\n" |
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35 | "1\n" |
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36 | "2\n" |
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37 | "3\n" |
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38 | "4\n" |
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39 | "@arcs\n" |
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40 | " length\n" |
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41 | "0 1 3\n" |
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42 | "1 2 -3\n" |
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43 | "1 2 -5\n" |
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44 | "1 3 -2\n" |
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45 | "0 2 -1\n" |
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46 | "1 2 -4\n" |
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47 | "0 3 2\n" |
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48 | "4 2 -5\n" |
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49 | "2 3 1\n" |
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50 | "@attributes\n" |
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51 | "source 0\n" |
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52 | "target 3\n"; |
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53 | |
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54 | |
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55 | void checkBellmanFordCompile() |
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56 | { |
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57 | typedef int Value; |
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58 | typedef concepts::Digraph Digraph; |
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59 | typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap; |
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60 | typedef BellmanFord<Digraph, LengthMap> BF; |
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61 | typedef Digraph::Node Node; |
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62 | typedef Digraph::Arc Arc; |
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63 | |
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64 | Digraph gr; |
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65 | Node s, t, n; |
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66 | Arc e; |
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67 | Value l; |
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68 | int k=3; |
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69 | bool b; |
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70 | BF::DistMap d(gr); |
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71 | BF::PredMap p(gr); |
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72 | LengthMap length; |
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73 | concepts::Path<Digraph> pp; |
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74 | |
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75 | { |
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76 | BF bf_test(gr,length); |
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77 | const BF& const_bf_test = bf_test; |
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78 | |
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79 | bf_test.run(s); |
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80 | bf_test.run(s,k); |
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81 | |
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82 | bf_test.init(); |
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83 | bf_test.addSource(s); |
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84 | bf_test.addSource(s, 1); |
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85 | b = bf_test.processNextRound(); |
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86 | b = bf_test.processNextWeakRound(); |
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87 | |
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88 | bf_test.start(); |
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89 | bf_test.checkedStart(); |
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90 | bf_test.limitedStart(k); |
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91 | |
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92 | l = const_bf_test.dist(t); |
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93 | e = const_bf_test.predArc(t); |
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94 | s = const_bf_test.predNode(t); |
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95 | b = const_bf_test.reached(t); |
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96 | d = const_bf_test.distMap(); |
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97 | p = const_bf_test.predMap(); |
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98 | pp = const_bf_test.path(t); |
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99 | pp = const_bf_test.negativeCycle(); |
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100 | |
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101 | for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {} |
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102 | } |
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103 | { |
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104 | BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> > |
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105 | ::SetDistMap<concepts::ReadWriteMap<Node,Value> > |
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106 | ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> > |
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107 | ::Create bf_test(gr,length); |
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108 | |
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109 | LengthMap length_map; |
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110 | concepts::ReadWriteMap<Node,Arc> pred_map; |
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111 | concepts::ReadWriteMap<Node,Value> dist_map; |
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112 | |
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113 | bf_test |
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114 | .lengthMap(length_map) |
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115 | .predMap(pred_map) |
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116 | .distMap(dist_map); |
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117 | |
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118 | bf_test.run(s); |
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119 | bf_test.run(s,k); |
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120 | |
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121 | bf_test.init(); |
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122 | bf_test.addSource(s); |
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123 | bf_test.addSource(s, 1); |
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124 | b = bf_test.processNextRound(); |
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125 | b = bf_test.processNextWeakRound(); |
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126 | |
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127 | bf_test.start(); |
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128 | bf_test.checkedStart(); |
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129 | bf_test.limitedStart(k); |
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130 | |
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131 | l = bf_test.dist(t); |
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132 | e = bf_test.predArc(t); |
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133 | s = bf_test.predNode(t); |
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134 | b = bf_test.reached(t); |
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135 | pp = bf_test.path(t); |
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136 | pp = bf_test.negativeCycle(); |
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137 | } |
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138 | } |
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139 | |
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140 | void checkBellmanFordFunctionCompile() |
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141 | { |
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142 | typedef int Value; |
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143 | typedef concepts::Digraph Digraph; |
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144 | typedef Digraph::Arc Arc; |
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145 | typedef Digraph::Node Node; |
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146 | typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap; |
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147 | |
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148 | Digraph g; |
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149 | bool b; |
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150 | bellmanFord(g,LengthMap()).run(Node()); |
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151 | b = bellmanFord(g,LengthMap()).run(Node(),Node()); |
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152 | bellmanFord(g,LengthMap()) |
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153 | .predMap(concepts::ReadWriteMap<Node,Arc>()) |
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154 | .distMap(concepts::ReadWriteMap<Node,Value>()) |
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155 | .run(Node()); |
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156 | b=bellmanFord(g,LengthMap()) |
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157 | .predMap(concepts::ReadWriteMap<Node,Arc>()) |
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158 | .distMap(concepts::ReadWriteMap<Node,Value>()) |
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159 | .path(concepts::Path<Digraph>()) |
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160 | .dist(Value()) |
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161 | .run(Node(),Node()); |
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162 | } |
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163 | |
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164 | |
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165 | template <typename Digraph, typename Value> |
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166 | void checkBellmanFord() { |
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167 | TEMPLATE_DIGRAPH_TYPEDEFS(Digraph); |
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168 | typedef typename Digraph::template ArcMap<Value> LengthMap; |
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169 | |
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170 | Digraph gr; |
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171 | Node s, t; |
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172 | LengthMap length(gr); |
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173 | |
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174 | std::istringstream input(test_lgf); |
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175 | digraphReader(gr, input). |
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176 | arcMap("length", length). |
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177 | node("source", s). |
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178 | node("target", t). |
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179 | run(); |
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180 | |
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181 | BellmanFord<Digraph, LengthMap> |
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182 | bf(gr, length); |
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183 | bf.run(s); |
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184 | Path<Digraph> p = bf.path(t); |
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185 | |
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186 | check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path."); |
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187 | check(p.length() == 3, "path() found a wrong path."); |
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188 | check(checkPath(gr, p), "path() found a wrong path."); |
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189 | check(pathSource(gr, p) == s, "path() found a wrong path."); |
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190 | check(pathTarget(gr, p) == t, "path() found a wrong path."); |
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191 | |
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192 | ListPath<Digraph> path; |
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193 | Value dist; |
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194 | bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t); |
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195 | |
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196 | check(reached && dist == -1, "Bellman-Ford found a wrong path."); |
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197 | check(path.length() == 3, "path() found a wrong path."); |
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198 | check(checkPath(gr, path), "path() found a wrong path."); |
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199 | check(pathSource(gr, path) == s, "path() found a wrong path."); |
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200 | check(pathTarget(gr, path) == t, "path() found a wrong path."); |
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201 | |
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202 | for(ArcIt e(gr); e!=INVALID; ++e) { |
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203 | Node u=gr.source(e); |
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204 | Node v=gr.target(e); |
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205 | check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]), |
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206 | "Wrong output. dist(target)-dist(source)-arc_length=" << |
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207 | bf.dist(v) - bf.dist(u) - length[e]); |
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208 | } |
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209 | |
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210 | for(NodeIt v(gr); v!=INVALID; ++v) { |
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211 | if (bf.reached(v)) { |
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212 | check(v==s || bf.predArc(v)!=INVALID, "Wrong tree."); |
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213 | if (bf.predArc(v)!=INVALID ) { |
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214 | Arc e=bf.predArc(v); |
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215 | Node u=gr.source(e); |
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216 | check(u==bf.predNode(v),"Wrong tree."); |
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217 | check(bf.dist(v) - bf.dist(u) == length[e], |
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218 | "Wrong distance! Difference: " << |
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219 | bf.dist(v) - bf.dist(u) - length[e]); |
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220 | } |
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221 | } |
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222 | } |
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223 | } |
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224 | |
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225 | void checkBellmanFordNegativeCycle() { |
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226 | DIGRAPH_TYPEDEFS(SmartDigraph); |
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227 | |
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228 | SmartDigraph gr; |
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229 | IntArcMap length(gr); |
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230 | |
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231 | Node n1 = gr.addNode(); |
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232 | Node n2 = gr.addNode(); |
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233 | Node n3 = gr.addNode(); |
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234 | Node n4 = gr.addNode(); |
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235 | |
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236 | Arc a1 = gr.addArc(n1, n2); |
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237 | Arc a2 = gr.addArc(n2, n2); |
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238 | |
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239 | length[a1] = 2; |
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240 | length[a2] = -1; |
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241 | |
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242 | { |
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243 | BellmanFord<SmartDigraph, IntArcMap> bf(gr, length); |
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244 | bf.run(n1); |
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245 | StaticPath<SmartDigraph> p = bf.negativeCycle(); |
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246 | check(p.length() == 1 && p.front() == p.back() && p.front() == a2, |
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247 | "Wrong negative cycle."); |
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248 | } |
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249 | |
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250 | length[a2] = 0; |
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251 | |
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252 | { |
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253 | BellmanFord<SmartDigraph, IntArcMap> bf(gr, length); |
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254 | bf.run(n1); |
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255 | check(bf.negativeCycle().empty(), |
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256 | "Negative cycle should not be found."); |
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257 | } |
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258 | |
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259 | length[gr.addArc(n1, n3)] = 5; |
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260 | length[gr.addArc(n4, n3)] = 1; |
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261 | length[gr.addArc(n2, n4)] = 2; |
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262 | length[gr.addArc(n3, n2)] = -4; |
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263 | |
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264 | { |
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265 | BellmanFord<SmartDigraph, IntArcMap> bf(gr, length); |
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266 | bf.init(); |
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267 | bf.addSource(n1); |
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268 | for (int i = 0; i < 4; ++i) { |
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269 | check(bf.negativeCycle().empty(), |
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270 | "Negative cycle should not be found."); |
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271 | bf.processNextRound(); |
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272 | } |
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273 | StaticPath<SmartDigraph> p = bf.negativeCycle(); |
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274 | check(p.length() == 3, "Wrong negative cycle."); |
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275 | check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1, |
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276 | "Wrong negative cycle."); |
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277 | } |
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278 | } |
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279 | |
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280 | int main() { |
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281 | checkBellmanFord<ListDigraph, int>(); |
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282 | checkBellmanFord<SmartDigraph, double>(); |
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283 | checkBellmanFordNegativeCycle(); |
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284 | return 0; |
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285 | } |
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