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 | #ifndef LEMON_MIN_COST_FLOW_H |
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20 | #define LEMON_MIN_COST_FLOW_H |
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21 | |
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22 | /// \ingroup min_cost_flow |
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23 | /// |
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24 | /// \file |
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25 | /// \brief An efficient algorithm for finding a minimum cost flow. |
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26 | |
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27 | #include <lemon/network_simplex.h> |
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28 | |
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29 | namespace lemon { |
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30 | |
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31 | /// \addtogroup min_cost_flow |
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32 | /// @{ |
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33 | |
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34 | /// \brief An efficient algorithm for finding a minimum cost flow. |
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35 | /// |
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36 | /// \ref MinCostFlow provides an efficient algorithm for finding |
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37 | /// a minimum cost flow. |
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38 | /// |
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39 | /// This class is just an alias for \ref NetworkSimplex, |
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40 | /// which is the most efficient algorithm for the minimum cost |
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41 | /// flow problem in LEMON according to our benchmark tests. |
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42 | /// For the detailed documentation of this class see |
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43 | /// \ref NetworkSimplex. |
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44 | /// |
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45 | /// There are four implementations for the minimum cost flow problem, |
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46 | /// which can be used exactly the same way except for the fact that |
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47 | /// \ref CycleCanceling does not provide dual solution (node |
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48 | /// potentials) since it is a pure primal method. |
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49 | /// - \ref CapacityScaling The capacity scaling algorithm. |
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50 | /// - \ref CostScaling The cost scaling algorithm. |
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51 | /// - \ref CycleCanceling A cycle-canceling algorithm. |
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52 | /// - \ref NetworkSimplex The network simplex algorithm. |
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53 | /// |
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54 | /// \tparam Graph The directed graph type the algorithm runs on. |
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55 | /// \tparam LowerMap The type of the lower bound map. |
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56 | /// \tparam CapacityMap The type of the capacity (upper bound) map. |
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57 | /// \tparam CostMap The type of the cost (length) map. |
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58 | /// \tparam SupplyMap The type of the supply map. |
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59 | /// |
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60 | /// \warning |
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61 | /// - Edge capacities and costs should be \e non-negative \e integers. |
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62 | /// - Supply values should be \e signed \e integers. |
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63 | /// - \c LowerMap::Value must be convertible to \c CapacityMap::Value. |
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64 | /// - \c CapacityMap::Value and \c SupplyMap::Value must be |
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65 | /// convertible to each other. |
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66 | /// - All value types must be convertible to \c CostMap::Value, which |
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67 | /// must be signed type. |
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68 | /// |
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69 | /// \author Peter Kovacs |
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70 | |
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71 | template < typename Graph, |
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72 | typename LowerMap = typename Graph::template EdgeMap<int>, |
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73 | typename CapacityMap = LowerMap, |
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74 | typename CostMap = typename Graph::template EdgeMap<int>, |
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75 | typename SupplyMap = typename Graph::template NodeMap |
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76 | <typename CapacityMap::Value> > |
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77 | class MinCostFlow : |
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78 | public NetworkSimplex< Graph, LowerMap, CapacityMap, |
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79 | CostMap, SupplyMap > |
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80 | { |
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81 | typedef NetworkSimplex< Graph, LowerMap, CapacityMap, |
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82 | CostMap, SupplyMap > MinCostFlowImpl; |
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83 | typedef typename Graph::Node Node; |
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84 | typedef typename SupplyMap::Value Supply; |
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85 | |
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86 | public: |
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87 | |
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88 | /// General constructor of the class (with lower bounds). |
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89 | MinCostFlow( const Graph &graph, |
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90 | const LowerMap &lower, |
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91 | const CapacityMap &capacity, |
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92 | const CostMap &cost, |
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93 | const SupplyMap &supply ) : |
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94 | MinCostFlowImpl(graph, lower, capacity, cost, supply) {} |
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95 | |
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96 | /// General constructor of the class (without lower bounds). |
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97 | MinCostFlow( const Graph &graph, |
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98 | const CapacityMap &capacity, |
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99 | const CostMap &cost, |
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100 | const SupplyMap &supply ) : |
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101 | MinCostFlowImpl(graph, capacity, cost, supply) {} |
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102 | |
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103 | /// Simple constructor of the class (with lower bounds). |
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104 | MinCostFlow( const Graph &graph, |
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105 | const LowerMap &lower, |
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106 | const CapacityMap &capacity, |
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107 | const CostMap &cost, |
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108 | Node s, Node t, |
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109 | Supply flow_value ) : |
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110 | MinCostFlowImpl( graph, lower, capacity, cost, |
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111 | s, t, flow_value ) {} |
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112 | |
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113 | /// Simple constructor of the class (without lower bounds). |
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114 | MinCostFlow( const Graph &graph, |
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115 | const CapacityMap &capacity, |
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116 | const CostMap &cost, |
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117 | Node s, Node t, |
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118 | Supply flow_value ) : |
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119 | MinCostFlowImpl( graph, capacity, cost, |
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120 | s, t, flow_value ) {} |
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121 | |
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122 | }; //class MinCostFlow |
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123 | |
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124 | ///@} |
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125 | |
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126 | } //namespace lemon |
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127 | |
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128 | #endif //LEMON_MIN_COST_FLOW_H |
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