Changeset 607:327f7cf13843 in lemon-0.x for src/work/athos/minlengthpaths.h
- Timestamp:
- 05/11/04 17:42:11 (20 years ago)
- Branch:
- default
- Phase:
- public
- Convert:
- svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@789
- File:
-
- 1 edited
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src/work/athos/minlengthpaths.h
r520 r607 8 8 9 9 #include <iostream> 10 #include <dijkstra.h> 11 #include <graph_wrapper.h> 12 #include <maps.h> 13 #include <vector.h> 14 10 //#include <hugo/dijkstra.h> 11 //#include <hugo/graph_wrapper.h> 12 #include <hugo/maps.h> 13 #include <vector> 14 #include <mincostflows.h> 15 #include <for_each_macros.h> 15 16 16 17 namespace hugo { … … 27 28 /// edge-weighted directed graph having minimal total weigth (length). 28 29 /// 30 ///\warning It is assumed that the lengths are positive, since the 31 /// general flow-decomposition is not implemented yet. 32 /// 29 33 ///\author Attila Bernath 30 34 template <typename Graph, typename LengthMap> 31 class MinLengthPaths { 35 class MinLengthPaths{ 36 32 37 33 38 typedef typename LengthMap::ValueType Length; … … 41 46 typedef ConstMap<Edge,int> ConstMap; 42 47 43 typedef ResGraphWrapper<const Graph,int,ConstMap,EdgeIntMap> ResGraphType; 48 //Input 49 const Graph& G; 44 50 45 class ModLengthMap { 46 typedef typename ResGraphType::template NodeMap<Length> NodeMap; 47 const ResGraphType& G; 48 const EdgeIntMap& rev; 49 const LengthMap &ol; 50 const NodeMap &pot; 51 public : 52 typedef typename LengthMap::KeyType KeyType; 53 typedef typename LengthMap::ValueType ValueType; 54 55 ValueType operator[](typename ResGraphType::Edge e) const { 56 //if ( (1-2*rev[e])*ol[e]-(pot[G.head(e)]-pot[G.tail(e)] ) <0 ){ 57 // std::cout<<"Negative length!!"<<std::endl; 58 //} 59 return (1-2*rev[e])*ol[e]-(pot[G.head(e)]-pot[G.tail(e)]); 60 } 61 62 ModLengthMap(const ResGraphType& _G, const EdgeIntMap& _rev, 63 const LengthMap &o, const NodeMap &p) : 64 G(_G), rev(_rev), ol(o), pot(p){}; 65 };//ModLengthMap 51 //Auxiliary variables 52 //This is the capacity map for the mincostflow problem 53 ConstMap const1map; 54 //This MinCostFlows instance will actually solve the problem 55 MinCostFlows<Graph, LengthMap, ConstMap> mincost_flow; 66 56 67 68 69 70 const Graph& G;71 const LengthMap& length;72 73 //auxiliary variables74 75 //The value is 1 iff the edge is reversed.76 //If the algorithm has finished, the edges of the seeked paths are77 //exactly those that are reversed78 EdgeIntMap reversed;79 80 57 //Container to store found paths 81 58 std::vector< std::vector<Edge> > paths; 82 //typedef DirPath<Graph> DPath;83 //DPath paths;84 85 86 Length total_length;87 59 88 60 public : 89 61 90 62 91 MinLengthPaths(Graph& _G, LengthMap& _length) : G(_G), 92 length(_length), reversed(_G)/*, dijkstra_dist(_G)*/{}63 MinLengthPaths(Graph& _G, LengthMap& _length) : G(_G), 64 const1map(1), mincost_flow(_G, _length, const1map){} 93 65 94 95 66 ///Runs the algorithm. 96 67 97 68 ///Runs the algorithm. 98 69 ///Returns k if there are at least k edge-disjoint paths from s to t. 99 70 ///Otherwise it returns the number of found edge-disjoint paths from s to t. 100 71 int run(Node s, Node t, int k) { 101 ConstMap const1map(1); 72 73 int i = mincost_flow.run(s,t,k); 74 102 75 103 76 104 //We need a residual graph, in which some of the edges are reversed105 ResGraphType res_graph(G, const1map, reversed);106 107 //Initialize the copy of the Dijkstra potential to zero108 typename ResGraphType::template NodeMap<Length> dijkstra_dist(res_graph);109 ModLengthMap mod_length(res_graph, reversed, length, dijkstra_dist);110 111 Dijkstra<ResGraphType, ModLengthMap> dijkstra(res_graph, mod_length);112 113 int i;114 for (i=0; i<k; ++i){115 dijkstra.run(s);116 if (!dijkstra.reached(t)){117 //There are no k paths from s to t118 break;119 };120 121 {122 //We have to copy the potential123 typename ResGraphType::NodeIt n;124 for ( res_graph.first(n) ; res_graph.valid(n) ; res_graph.next(n) ) {125 dijkstra_dist[n] += dijkstra.distMap()[n];126 }127 }128 129 130 //Reversing the sortest path131 Node n=t;132 Edge e;133 while (n!=s){134 e = dijkstra.pred(n);135 n = dijkstra.predNode(n);136 reversed[e] = 1-reversed[e];137 }138 139 140 }141 142 77 //Let's find the paths 143 78 //We put the paths into stl vectors (as an inner representation). … … 145 80 //We suppose the lengths to be positive now. 146 81 147 //Meanwhile we put the total length of the found paths 148 //in the member variable total_length 82 //We don't want to change the flow of mincost_flow, so we make a copy 83 //The name here suggests that the flow has only 0/1 values. 84 EdgeIntMap reversed(G); 85 86 FOR_EACH_LOC(typename Graph::EdgeIt, e, G){ 87 reversed[e] = mincost_flow.getFlow()[e]; 88 } 89 149 90 paths.clear(); 150 total_length=0;91 //total_length=0; 151 92 paths.resize(k); 152 93 for (int j=0; j<i; ++j){ … … 164 105 n = G.head(e); 165 106 paths[j].push_back(e); 166 total_length += length[e];107 //total_length += length[e]; 167 108 reversed[e] = 1-reversed[e]; 168 109 } 169 110 170 111 } 171 172 112 return i; 173 113 } 174 114 115 175 116 ///This function gives back the total length of the found paths. 176 117 ///Assumes that \c run() has been run and nothing changed since then. 177 118 Length totalLength(){ 178 return total_length; 119 return mincost_flow.totalLength(); 120 } 121 122 ///Returns a const reference to the EdgeMap \c flow. \pre \ref run() must 123 ///be called before using this function. 124 const EdgeIntMap &getFlow() const { return mincost_flow.flow;} 125 126 ///Returns a const reference to the NodeMap \c potential (the dual solution). 127 /// \pre \ref run() must be called before using this function. 128 const EdgeIntMap &getPotential() const { return mincost_flow.potential;} 129 130 ///This function checks, whether the given solution is optimal 131 ///Running after a \c run() should return with true 132 ///In this "state of the art" this only checks optimality, doesn't bother with feasibility 133 /// 134 ///\todo Is this OK here? 135 bool checkComplementarySlackness(){ 136 return mincost_flow.checkComplementarySlackness(); 179 137 } 180 138 181 139 ///This function gives back the \c j-th path in argument p. 182 140 ///Assumes that \c run() has been run and nothing changed since then. 183 /// \warning It is assumed that \c p is constructed to be a path of graph \c G. If \c j is greater than the result of previous \c run, then the result here will be an empty path.141 /// \warning It is assumed that \c p is constructed to be a path of graph \c G. If \c j is not less than the result of previous \c run, then the result here will be an empty path (\c j can be 0 as well). 184 142 template<typename DirPath> 185 void getPath(DirPath& p, int j){ 143 void getPath(DirPath& p, size_t j){ 144 186 145 p.clear(); 146 if (j>paths.size()-1){ 147 return; 148 } 187 149 typename DirPath::Builder B(p); 188 150 for(typename std::vector<Edge>::iterator i=paths[j].begin();
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