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) 2003-2013 |
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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 <iostream> |
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20 | |
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21 | #include "test_tools.h" |
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22 | #include <lemon/smart_graph.h> |
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23 | #include <lemon/preflow.h> |
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24 | #include <lemon/edmonds_karp.h> |
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25 | #include <lemon/concepts/digraph.h> |
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26 | #include <lemon/concepts/maps.h> |
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27 | #include <lemon/lgf_reader.h> |
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28 | #include <lemon/elevator.h> |
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29 | |
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30 | using namespace lemon; |
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31 | |
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32 | char test_lgf[] = |
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33 | "@nodes\n" |
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34 | "label\n" |
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35 | "0\n" |
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36 | "1\n" |
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37 | "2\n" |
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38 | "3\n" |
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39 | "4\n" |
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40 | "5\n" |
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41 | "6\n" |
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42 | "7\n" |
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43 | "8\n" |
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44 | "9\n" |
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45 | "@arcs\n" |
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46 | " label capacity\n" |
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47 | "0 1 0 20\n" |
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48 | "0 2 1 0\n" |
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49 | "1 1 2 3\n" |
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50 | "1 2 3 8\n" |
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51 | "1 3 4 8\n" |
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52 | "2 5 5 5\n" |
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53 | "3 2 6 5\n" |
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54 | "3 5 7 5\n" |
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55 | "3 6 8 5\n" |
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56 | "4 3 9 3\n" |
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57 | "5 7 10 3\n" |
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58 | "5 6 11 10\n" |
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59 | "5 8 12 10\n" |
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60 | "6 8 13 8\n" |
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61 | "8 9 14 20\n" |
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62 | "8 1 15 5\n" |
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63 | "9 5 16 5\n" |
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64 | "@attributes\n" |
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65 | "source 1\n" |
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66 | "target 8\n"; |
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67 | |
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68 | |
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69 | // Checks the general interface of a max flow algorithm |
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70 | template <typename GR, typename CAP> |
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71 | struct MaxFlowClassConcept |
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72 | { |
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73 | |
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74 | template <typename MF> |
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75 | struct Constraints { |
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76 | |
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77 | typedef typename GR::Node Node; |
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78 | typedef typename GR::Arc Arc; |
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79 | typedef typename CAP::Value Value; |
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80 | typedef concepts::ReadWriteMap<Arc, Value> FlowMap; |
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81 | typedef concepts::WriteMap<Node, bool> CutMap; |
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82 | |
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83 | GR g; |
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84 | Node n; |
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85 | Arc e; |
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86 | CAP cap; |
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87 | FlowMap flow; |
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88 | CutMap cut; |
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89 | Value v; |
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90 | bool b; |
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91 | |
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92 | void constraints() { |
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93 | checkConcept<concepts::Digraph, GR>(); |
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94 | |
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95 | const Constraints& me = *this; |
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96 | |
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97 | typedef typename MF |
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98 | ::template SetFlowMap<FlowMap> |
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99 | ::Create MaxFlowType; |
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100 | typedef typename MF::Create MaxFlowType2; |
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101 | MaxFlowType max_flow(me.g, me.cap, me.n, me.n); |
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102 | const MaxFlowType& const_max_flow = max_flow; |
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103 | |
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104 | max_flow |
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105 | .capacityMap(cap) |
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106 | .flowMap(flow) |
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107 | .source(n) |
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108 | .target(n); |
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109 | |
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110 | typename MaxFlowType::Tolerance tol = const_max_flow.tolerance(); |
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111 | max_flow.tolerance(tol); |
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112 | |
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113 | max_flow.init(); |
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114 | max_flow.init(cap); |
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115 | max_flow.run(); |
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116 | |
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117 | v = const_max_flow.flowValue(); |
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118 | v = const_max_flow.flow(e); |
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119 | const FlowMap& fm = const_max_flow.flowMap(); |
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120 | |
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121 | b = const_max_flow.minCut(n); |
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122 | const_max_flow.minCutMap(cut); |
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123 | |
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124 | ::lemon::ignore_unused_variable_warning(fm); |
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125 | } |
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126 | |
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127 | }; |
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128 | |
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129 | }; |
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130 | |
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131 | // Checks the specific parts of Preflow's interface |
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132 | void checkPreflowCompile() |
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133 | { |
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134 | typedef int Value; |
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135 | typedef concepts::Digraph Digraph; |
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136 | typedef concepts::ReadMap<Digraph::Arc, Value> CapMap; |
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137 | typedef Elevator<Digraph, Digraph::Node> Elev; |
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138 | typedef LinkedElevator<Digraph, Digraph::Node> LinkedElev; |
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139 | |
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140 | Digraph g; |
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141 | Digraph::Node n; |
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142 | CapMap cap; |
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143 | |
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144 | typedef Preflow<Digraph, CapMap> |
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145 | ::SetElevator<Elev> |
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146 | ::SetStandardElevator<LinkedElev> |
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147 | ::Create PreflowType; |
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148 | PreflowType preflow_test(g, cap, n, n); |
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149 | const PreflowType& const_preflow_test = preflow_test; |
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150 | |
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151 | const PreflowType::Elevator& elev = const_preflow_test.elevator(); |
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152 | preflow_test.elevator(const_cast<PreflowType::Elevator&>(elev)); |
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153 | |
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154 | bool b = preflow_test.init(cap); |
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155 | preflow_test.startFirstPhase(); |
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156 | preflow_test.startSecondPhase(); |
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157 | preflow_test.runMinCut(); |
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158 | |
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159 | ::lemon::ignore_unused_variable_warning(b); |
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160 | } |
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161 | |
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162 | // Checks the specific parts of EdmondsKarp's interface |
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163 | void checkEdmondsKarpCompile() |
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164 | { |
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165 | typedef int Value; |
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166 | typedef concepts::Digraph Digraph; |
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167 | typedef concepts::ReadMap<Digraph::Arc, Value> CapMap; |
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168 | |
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169 | Digraph g; |
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170 | Digraph::Node n; |
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171 | CapMap cap; |
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172 | |
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173 | EdmondsKarp<Digraph, CapMap> ek_test(g, cap, n, n); |
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174 | |
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175 | ek_test.init(cap); |
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176 | bool b = ek_test.checkedInit(cap); |
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177 | b = ek_test.augment(); |
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178 | ek_test.start(); |
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179 | |
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180 | ::lemon::ignore_unused_variable_warning(b); |
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181 | } |
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182 | |
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183 | |
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184 | template <typename T> |
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185 | T cutValue(const SmartDigraph& g, |
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186 | const SmartDigraph::NodeMap<bool>& cut, |
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187 | const SmartDigraph::ArcMap<T>& cap) { |
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188 | |
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189 | T c = 0; |
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190 | for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) { |
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191 | if (cut[g.source(e)] && !cut[g.target(e)]) c += cap[e]; |
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192 | } |
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193 | return c; |
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194 | } |
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195 | |
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196 | template <typename T> |
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197 | bool checkFlow(const SmartDigraph& g, |
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198 | const SmartDigraph::ArcMap<T>& flow, |
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199 | const SmartDigraph::ArcMap<T>& cap, |
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200 | SmartDigraph::Node s, SmartDigraph::Node t) { |
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201 | |
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202 | for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) { |
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203 | if (flow[e] < 0 || flow[e] > cap[e]) return false; |
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204 | } |
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205 | |
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206 | for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) { |
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207 | if (n == s || n == t) continue; |
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208 | T sum = 0; |
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209 | for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) { |
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210 | sum += flow[e]; |
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211 | } |
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212 | for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) { |
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213 | sum -= flow[e]; |
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214 | } |
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215 | if (sum != 0) return false; |
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216 | } |
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217 | return true; |
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218 | } |
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219 | |
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220 | void checkInitPreflow() |
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221 | { |
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222 | DIGRAPH_TYPEDEFS(SmartDigraph); |
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223 | |
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224 | SmartDigraph g; |
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225 | SmartDigraph::ArcMap<int> cap(g), iflow(g); |
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226 | Node s = g.addNode(); Node t = g.addNode(); |
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227 | Node n1 = g.addNode(); Node n2 = g.addNode(); |
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228 | Arc a; |
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229 | a = g.addArc(s, n1); cap[a] = 20; iflow[a] = 20; |
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230 | a = g.addArc(n1, n2); cap[a] = 10; iflow[a] = 0; |
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231 | a = g.addArc(n2, t); cap[a] = 20; iflow[a] = 0; |
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232 | |
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233 | Preflow<SmartDigraph> pre(g, cap, s, t); |
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234 | pre.init(iflow); |
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235 | pre.startFirstPhase(); |
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236 | |
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237 | check(pre.flowValue() == 10, "Incorrect max flow value."); |
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238 | check(pre.minCut(s), "Wrong min cut (Node s)."); |
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239 | check(pre.minCut(n1), "Wrong min cut (Node n1)."); |
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240 | check(!pre.minCut(n2), "Wrong min cut (Node n2)."); |
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241 | check(!pre.minCut(t), "Wrong min cut (Node t)."); |
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242 | } |
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243 | |
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244 | template <typename MF, typename SF> |
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245 | void checkMaxFlowAlg() { |
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246 | typedef SmartDigraph Digraph; |
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247 | DIGRAPH_TYPEDEFS(Digraph); |
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248 | |
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249 | typedef typename MF::Value Value; |
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250 | typedef Digraph::ArcMap<Value> CapMap; |
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251 | typedef CapMap FlowMap; |
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252 | typedef BoolNodeMap CutMap; |
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253 | |
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254 | Digraph g; |
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255 | Node s, t; |
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256 | CapMap cap(g); |
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257 | std::istringstream input(test_lgf); |
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258 | DigraphReader<Digraph>(g,input) |
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259 | .arcMap("capacity", cap) |
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260 | .node("source",s) |
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261 | .node("target",t) |
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262 | .run(); |
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263 | |
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264 | MF max_flow(g, cap, s, t); |
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265 | max_flow.run(); |
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266 | |
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267 | check(checkFlow(g, max_flow.flowMap(), cap, s, t), |
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268 | "The flow is not feasible."); |
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269 | |
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270 | CutMap min_cut(g); |
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271 | max_flow.minCutMap(min_cut); |
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272 | Value min_cut_value = cutValue(g, min_cut, cap); |
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273 | |
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274 | check(max_flow.flowValue() == min_cut_value, |
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275 | "The max flow value is not equal to the min cut value."); |
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276 | |
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277 | FlowMap flow(g); |
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278 | for (ArcIt e(g); e != INVALID; ++e) flow[e] = max_flow.flowMap()[e]; |
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279 | |
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280 | Value flow_value = max_flow.flowValue(); |
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281 | |
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282 | for (ArcIt e(g); e != INVALID; ++e) cap[e] = 2 * cap[e]; |
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283 | max_flow.init(flow); |
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284 | |
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285 | SF::startFirstPhase(max_flow); // start first phase of the algorithm |
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286 | |
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287 | CutMap min_cut1(g); |
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288 | max_flow.minCutMap(min_cut1); |
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289 | min_cut_value = cutValue(g, min_cut1, cap); |
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290 | |
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291 | check(max_flow.flowValue() == min_cut_value && |
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292 | min_cut_value == 2 * flow_value, |
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293 | "The max flow value or the min cut value is wrong."); |
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294 | |
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295 | SF::startSecondPhase(max_flow); // start second phase of the algorithm |
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296 | |
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297 | check(checkFlow(g, max_flow.flowMap(), cap, s, t), |
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298 | "The flow is not feasible."); |
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299 | |
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300 | CutMap min_cut2(g); |
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301 | max_flow.minCutMap(min_cut2); |
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302 | min_cut_value = cutValue(g, min_cut2, cap); |
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303 | |
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304 | check(max_flow.flowValue() == min_cut_value && |
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305 | min_cut_value == 2 * flow_value, |
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306 | "The max flow value or the min cut value was not doubled."); |
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307 | |
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308 | max_flow.flowMap(flow); |
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309 | |
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310 | NodeIt tmp1(g, s); |
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311 | ++tmp1; |
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312 | if (tmp1 != INVALID) s = tmp1; |
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313 | |
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314 | NodeIt tmp2(g, t); |
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315 | ++tmp2; |
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316 | if (tmp2 != INVALID) t = tmp2; |
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317 | |
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318 | max_flow.source(s); |
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319 | max_flow.target(t); |
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320 | |
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321 | max_flow.run(); |
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322 | |
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323 | CutMap min_cut3(g); |
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324 | max_flow.minCutMap(min_cut3); |
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325 | min_cut_value = cutValue(g, min_cut3, cap); |
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326 | |
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327 | check(max_flow.flowValue() == min_cut_value, |
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328 | "The max flow value or the min cut value is wrong."); |
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329 | } |
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330 | |
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331 | // Struct for calling start functions of a general max flow algorithm |
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332 | template <typename MF> |
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333 | struct GeneralStartFunctions { |
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334 | |
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335 | static void startFirstPhase(MF& mf) { |
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336 | mf.start(); |
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337 | } |
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338 | |
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339 | static void startSecondPhase(MF& mf) { |
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340 | ::lemon::ignore_unused_variable_warning(mf); |
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341 | } |
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342 | |
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343 | }; |
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344 | |
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345 | // Struct for calling start functions of Preflow |
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346 | template <typename MF> |
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347 | struct PreflowStartFunctions { |
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348 | |
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349 | static void startFirstPhase(MF& mf) { |
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350 | mf.startFirstPhase(); |
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351 | } |
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352 | |
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353 | static void startSecondPhase(MF& mf) { |
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354 | mf.startSecondPhase(); |
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355 | } |
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356 | |
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357 | }; |
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358 | |
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359 | int main() { |
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360 | |
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361 | typedef concepts::Digraph GR; |
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362 | typedef concepts::ReadMap<GR::Arc, int> CM1; |
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363 | typedef concepts::ReadMap<GR::Arc, double> CM2; |
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364 | |
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365 | // Check the interface of Preflow |
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366 | checkConcept< MaxFlowClassConcept<GR, CM1>, |
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367 | Preflow<GR, CM1> >(); |
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368 | checkConcept< MaxFlowClassConcept<GR, CM2>, |
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369 | Preflow<GR, CM2> >(); |
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370 | |
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371 | // Check the interface of EdmondsKarp |
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372 | checkConcept< MaxFlowClassConcept<GR, CM1>, |
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373 | EdmondsKarp<GR, CM1> >(); |
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374 | checkConcept< MaxFlowClassConcept<GR, CM2>, |
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375 | EdmondsKarp<GR, CM2> >(); |
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376 | |
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377 | // Check Preflow |
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378 | typedef Preflow<SmartDigraph, SmartDigraph::ArcMap<int> > PType1; |
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379 | typedef Preflow<SmartDigraph, SmartDigraph::ArcMap<float> > PType2; |
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380 | checkMaxFlowAlg<PType1, PreflowStartFunctions<PType1> >(); |
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381 | checkMaxFlowAlg<PType2, PreflowStartFunctions<PType2> >(); |
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382 | |
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383 | checkInitPreflow(); |
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384 | |
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385 | // Check EdmondsKarp |
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386 | typedef EdmondsKarp<SmartDigraph, SmartDigraph::ArcMap<int> > EKType1; |
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387 | typedef EdmondsKarp<SmartDigraph, SmartDigraph::ArcMap<float> > EKType2; |
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388 | checkMaxFlowAlg<EKType1, GeneralStartFunctions<EKType1> >(); |
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389 | checkMaxFlowAlg<EKType2, GeneralStartFunctions<EKType2> >(); |
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390 | |
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391 | return 0; |
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392 | } |
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