Changeset 860:3577b3db6089 in lemon-0.x for src/hugo/mincostflows.h
- Timestamp:
- 09/16/04 12:26:14 (20 years ago)
- Branch:
- default
- Phase:
- public
- Convert:
- svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@1160
- File:
-
- 1 edited
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src/hugo/mincostflows.h
r788 r860 24 24 /// The class \ref hugo::MinCostFlows "MinCostFlows" implements 25 25 /// an algorithm for finding a flow of value \c k 26 /// (for small values of \c k)having minimal total cost26 /// having minimal total cost 27 27 /// from a given source node to a given target node in an 28 28 /// edge-weighted directed graph having nonnegative integer capacities. 29 /// The range of the length (weight) function is nonnegative reals but 30 /// the range of capacity function is the set of nonnegative integers. 31 /// It is not a polinomial time algorithm for counting the minimum cost 32 /// maximal flow, since it counts the minimum cost flow for every value 0..M 33 /// where \c M is the value of the maximal flow. 29 /// The range of the length (weight or cost) function can be nonnegative reals but 30 /// the range of the capacity function has to be the set of nonnegative integers. 31 /// This algorithm is intended to use only for for small values of \c k, since /// it is not a polinomial time algorithm for finding the minimum cost 32 /// maximal flow (in order to find the minimum cost flow of value \c k it 33 /// finds the minimum cost flow of value \c i for every 34 /// \c i between 0 and \c k). 35 /// 36 ///\param Graph The directed graph type the algorithm runs on. 37 ///\param LengthMap The type of the length map. 38 ///\param CapacityMap The capacity map type. 34 39 /// 35 40 ///\author Attila Bernath 36 41 template <typename Graph, typename LengthMap, typename CapacityMap> 37 42 class MinCostFlows { 43 44 38 45 39 46 typedef typename LengthMap::ValueType Length; … … 48 55 typedef typename Graph::template EdgeMap<int> EdgeIntMap; 49 56 50 // typedef ConstMap<Edge,int> ConstMap;51 57 52 58 typedef ResGraphWrapper<const Graph,int,CapacityMap,EdgeIntMap> ResGraphType; … … 54 60 55 61 class ModLengthMap { 56 //typedef typename ResGraphType::template NodeMap<Length> NodeMap;57 62 typedef typename Graph::template NodeMap<Length> NodeMap; 58 63 const ResGraphType& G; 59 // const EdgeIntMap& rev;60 64 const LengthMap &ol; 61 65 const NodeMap &pot; … … 99 103 public : 100 104 101 105 /// The constructor of the class. 106 107 ///\param _G The directed graph the algorithm runs on. 108 ///\param _length The length (weight or cost) of the edges. 109 ///\param _cap The capacity of the edges. 102 110 MinCostFlows(Graph& _G, LengthMap& _length, CapacityMap& _cap) : G(_G), 103 111 length(_length), capacity(_cap), flow(_G), potential(_G){ } … … 105 113 106 114 ///Runs the algorithm. 107 115 108 116 ///Runs the algorithm. 109 ///Returns k if there are at least k edge-disjoint paths from s to t. 110 ///Otherwise it returns the number of found edge-disjoint paths from s to t. 117 ///Returns k if there is a flow of value at least k edge-disjoint 118 ///from s to t. 119 ///Otherwise it returns the maximum value of a flow from s to t. 120 /// 121 ///\param s The source node. 122 ///\param t The target node. 123 ///\param k The value of the flow we are looking for. 124 /// 111 125 ///\todo May be it does make sense to be able to start with a nonzero 112 126 /// feasible primal-dual solution pair as well. … … 134 148 dijkstra.run(s); 135 149 if (!dijkstra.reached(t)){ 136 //There are no k pathsfrom s to t150 //There are no flow of value k from s to t 137 151 break; 138 152 }; … … 166 180 167 181 168 169 ///This function gives back the total length of the found paths. 182 /// Gives back the total weight of the found flow. 183 184 ///This function gives back the total weight of the found flow. 170 185 ///Assumes that \c run() has been run and nothing changed since then. 171 186 Length totalLength(){ … … 173 188 } 174 189 175 ///Returns a const reference to the EdgeMap \c flow. \pre \ref run() must 190 ///Returns a const reference to the EdgeMap \c flow. 191 192 ///Returns a const reference to the EdgeMap \c flow. 193 ///\pre \ref run() must 176 194 ///be called before using this function. 177 195 const EdgeIntMap &getFlow() const { return flow;} 178 196 179 ///Returns a const reference to the NodeMap \c potential (the dual solution). 197 ///Returns a const reference to the NodeMap \c potential (the dual solution). 198 199 ///Returns a const reference to the NodeMap \c potential (the dual solution). 180 200 /// \pre \ref run() must be called before using this function. 181 201 const PotentialMap &getPotential() const { return potential;} 182 202 203 /// Checking the complementary slackness optimality criteria 204 183 205 ///This function checks, whether the given solution is optimal 184 ///Running after a \c run() should return with true 185 ///In this "state of the art" this only check optimality, doesn't bother with feasibility 206 ///If executed after the call of \c run() then it should return with true. 207 ///This function only checks optimality, doesn't bother with feasibility. 208 ///It is meant for testing purposes. 186 209 /// 187 ///\todo Is this OK here?188 210 bool checkComplementarySlackness(){ 189 211 Length mod_pot;
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