Changeset 863:d27bbe17b0b8 in lemon0.x for src/work/marci/tight_edge_filter_map.h
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 09/16/04 13:11:01 (17 years ago)
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src/work/marci/tight_edge_filter_map.h
r862 r863 1 1 // * C++ * 2 #ifndef HUGO_ AUGMENTING_FLOW_H3 #define HUGO_ AUGMENTING_FLOW_H2 #ifndef HUGO_TIGHT_EDGE_FILTER_MAP_H 3 #define HUGO_TIGHT_EDGE_FILTER_MAP_H 4 4 5 #include <vector> 6 //#include <queue> 7 //#include <stack> 8 #include <iostream> 9 10 #include <hugo/graph_wrapper.h> 11 #include <bfs_dfs.h> 12 #include <hugo/invalid.h> 13 #include <hugo/maps.h> 14 15 /// \file 16 /// \brief Maximum flow algorithms. 17 /// \ingroup galgs 5 // /// \file 6 // /// \brief Maximum flow algorithms. 7 // /// \ingroup galgs 18 8 19 9 namespace hugo { … … 44 34 g(&_g), node_potential(&_node_potential), 45 35 edge_distance(&_edge_distance) { } 46 // void set(const typename Graph::Node& n, int a) {47 // pot>set(n, a);48 // }49 // int operator[](const typename Graph::Node& n) const {50 // return (*node_potential)[n];51 // }52 36 bool operator[](const typename Graph::Edge& e) const { 53 37 return ((*node_potential)[g>head(e)] == … … 56 40 }; 57 41 58 /// \addtogroup galgs 59 /// @{ 60 /// Class for augmenting path flow algorithms. 42 } //namespace hugo 61 43 62 /// This class provides various algorithms for finding a flow of 63 /// maximum value in a directed graph. The \e source node, the \e 64 /// target node, the \e capacity of the edges and the \e starting \e 65 /// flow value of the edges should be passed to the algorithm through the 66 /// constructor. 67 // /// It is possible to change these quantities using the 68 // /// functions \ref resetSource, \ref resetTarget, \ref resetCap and 69 // /// \ref resetFlow. Before any subsequent runs of any algorithm of 70 // /// the class \ref resetFlow should be called. 71 72 /// After running an algorithm of the class, the actual flow value 73 /// can be obtained by calling \ref flowValue(). The minimum 74 /// value cut can be written into a \c node map of \c bools by 75 /// calling \ref minCut. (\ref minMinCut and \ref maxMinCut writes 76 /// the inclusionwise minimum and maximum of the minimum value 77 /// cuts, resp.) 78 ///\param Graph The directed graph type the algorithm runs on. 79 ///\param Num The number type of the capacities and the flow values. 80 ///\param CapMap The capacity map type. 81 ///\param FlowMap The flow map type. 82 ///\author Marton Makai 83 template <typename Graph, typename Num, 84 typename CapMap=typename Graph::template EdgeMap<Num>, 85 typename FlowMap=typename Graph::template EdgeMap<Num> > 86 class AugmentingFlow { 87 protected: 88 typedef typename Graph::Node Node; 89 typedef typename Graph::NodeIt NodeIt; 90 typedef typename Graph::EdgeIt EdgeIt; 91 typedef typename Graph::OutEdgeIt OutEdgeIt; 92 typedef typename Graph::InEdgeIt InEdgeIt; 93 94 const Graph* g; 95 Node s; 96 Node t; 97 const CapMap* capacity; 98 FlowMap* flow; 99 // int n; //the number of nodes of G 100 typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; 101 //typedef ExpResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; 102 typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt; 103 typedef typename ResGW::Edge ResGWEdge; 104 //typedef typename ResGW::template NodeMap<bool> ReachedMap; 105 typedef typename Graph::template NodeMap<int> ReachedMap; 106 107 //level works as a bool map in augmenting path algorithms and is 108 //used by bfs for storing reached information. In preflow, it 109 //shows the levels of nodes. 110 ReachedMap level; 111 112 public: 113 ///Indicates the property of the starting flow. 114 115 ///Indicates the property of the starting flow. The meanings are as follows: 116 /// \c ZERO_FLOW: constant zero flow 117 /// \c GEN_FLOW: any flow, i.e. the sum of the inflows equals to 118 ///the sum of the outflows in every node except the \e source and 119 ///the \e target. 120 /// \c PRE_FLOW: any preflow, i.e. the sum of the inflows is at 121 ///least the sum of the outflows in every node except the \e source. 122 /// \c NO_FLOW: indicates an unspecified edge map. \ref flow will be 123 ///set to the constant zero flow in the beginning of the algorithm in this case. 124 enum FlowEnum{ 125 ZERO_FLOW, 126 GEN_FLOW, 127 PRE_FLOW, 128 NO_FLOW 129 }; 130 131 enum StatusEnum { 132 AFTER_NOTHING, 133 AFTER_AUGMENTING, 134 AFTER_FAST_AUGMENTING, 135 AFTER_PRE_FLOW_PHASE_1, 136 AFTER_PRE_FLOW_PHASE_2 137 }; 138 139 /// Don not needle this flag only if necessary. 140 StatusEnum status; 141 int number_of_augmentations; 44 #endif //HUGO_TIGHT_EDGE_FILTER_MAP_H 142 45 143 46 144 template<typename IntMap>145 class TrickyReachedMap {146 protected:147 IntMap* map;148 int* number_of_augmentations;149 public:150 TrickyReachedMap(IntMap& _map, int& _number_of_augmentations) :151 map(&_map), number_of_augmentations(&_number_of_augmentations) { }152 void set(const Node& n, bool b) {153 if (b)154 map>set(n, *number_of_augmentations);155 else156 map>set(n, *number_of_augmentations1);157 }158 bool operator[](const Node& n) const {159 return (*map)[n]==*number_of_augmentations;160 }161 };162 163 AugmentingFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity,164 FlowMap& _flow) :165 g(&_G), s(_s), t(_t), capacity(&_capacity),166 flow(&_flow), //n(_G.nodeNum()),167 level(_G), //excess(_G,0),168 status(AFTER_NOTHING), number_of_augmentations(0) { }169 170 /// Starting from a flow, this method searches for an augmenting path171 /// according to the EdmondsKarp algorithm172 /// and augments the flow on if any.173 /// The return value shows if the augmentation was succesful.174 bool augmentOnShortestPath();175 bool augmentOnShortestPath2();176 177 /// Starting from a flow, this method searches for an augmenting blocking178 /// flow according to Dinits' algorithm and augments the flow on if any.179 /// The blocking flow is computed in a physically constructed180 /// residual graph of type \c Mutablegraph.181 /// The return value show sif the augmentation was succesful.182 template<typename MutableGraph> bool augmentOnBlockingFlow();183 184 /// The same as \c augmentOnBlockingFlow<MutableGraph> but the185 /// residual graph is not constructed physically.186 /// The return value shows if the augmentation was succesful.187 bool augmentOnBlockingFlow2();188 189 template<typename _CutMap>190 void actMinCut(_CutMap& M) const {191 NodeIt v;192 switch (status) {193 case AFTER_PRE_FLOW_PHASE_1:194 // std::cout << "AFTER_PRE_FLOW_PHASE_1" << std::endl;195 // for(g>first(v); g>valid(v); g>next(v)) {196 // if (level[v] < n) {197 // M.set(v, false);198 // } else {199 // M.set(v, true);200 // }201 // }202 break;203 case AFTER_PRE_FLOW_PHASE_2:204 // std::cout << "AFTER_PRE_FLOW_PHASE_2" << std::endl;205 break;206 case AFTER_NOTHING:207 // std::cout << "AFTER_NOTHING" << std::endl;208 minMinCut(M);209 break;210 case AFTER_AUGMENTING:211 // std::cout << "AFTER_AUGMENTING" << std::endl;212 for(g>first(v); v!=INVALID; ++v) {213 if (level[v]) {214 M.set(v, true);215 } else {216 M.set(v, false);217 }218 }219 break;220 case AFTER_FAST_AUGMENTING:221 // std::cout << "AFTER_FAST_AUGMENTING" << std::endl;222 for(g>first(v); v!=INVALID; ++v) {223 if (level[v]==number_of_augmentations) {224 M.set(v, true);225 } else {226 M.set(v, false);227 }228 }229 break;230 }231 }232 233 template<typename _CutMap>234 void minMinCut(_CutMap& M) const {235 std::queue<Node> queue;236 237 M.set(s,true);238 queue.push(s);239 240 while (!queue.empty()) {241 Node w=queue.front();242 queue.pop();243 244 OutEdgeIt e;245 for(g>first(e,w) ; e!=INVALID; ++e) {246 Node v=g>head(e);247 if (!M[v] && (*flow)[e] < (*capacity)[e] ) {248 queue.push(v);249 M.set(v, true);250 }251 }252 253 InEdgeIt f;254 for(g>first(f,w) ; f!=INVALID; ++f) {255 Node v=g>tail(f);256 if (!M[v] && (*flow)[f] > 0 ) {257 queue.push(v);258 M.set(v, true);259 }260 }261 }262 }263 264 template<typename _CutMap>265 void minMinCut2(_CutMap& M) const {266 ResGW res_graph(*g, *capacity, *flow);267 BfsIterator<ResGW, _CutMap> bfs(res_graph, M);268 bfs.pushAndSetReached(s);269 while (!bfs.finished()) ++bfs;270 }271 272 Num flowValue() const {273 Num a=0;274 for (InEdgeIt e(*g, t); e!=INVALID; ++e) a+=(*flow)[e];275 for (OutEdgeIt e(*g, t); e!=INVALID; ++e) a=(*flow)[e];276 return a;277 //marci figyu: excess[t] epp ezt adja preflow 1. fazisa utan278 }279 280 };281 282 283 284 template <typename Graph, typename Num, typename CapMap, typename FlowMap>285 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath()286 {287 ResGW res_graph(*g, *capacity, *flow);288 bool _augment=false;289 290 //ReachedMap level(res_graph);291 for (typename Graph::NodeIt n(*g); n!=INVALID; ++n) level.set(n, 0);292 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);293 bfs.pushAndSetReached(s);294 295 typename ResGW::template NodeMap<ResGWEdge> pred(res_graph);296 pred.set(s, INVALID);297 298 typename ResGW::template NodeMap<Num> free(res_graph);299 300 //searching for augmenting path301 while ( !bfs.finished() ) {302 ResGWEdge e=bfs;303 if (e!=INVALID && bfs.isBNodeNewlyReached()) {304 Node v=res_graph.tail(e);305 Node w=res_graph.head(e);306 pred.set(w, e);307 if (pred[v]!=INVALID) {308 free.set(w, std::min(free[v], res_graph.resCap(e)));309 } else {310 free.set(w, res_graph.resCap(e));311 }312 if (res_graph.head(e)==t) { _augment=true; break; }313 }314 315 ++bfs;316 } //end of searching augmenting path317 318 if (_augment) {319 Node n=t;320 Num augment_value=free[t];321 while (pred[n]!=INVALID) {322 ResGWEdge e=pred[n];323 res_graph.augment(e, augment_value);324 n=res_graph.tail(e);325 }326 }327 328 status=AFTER_AUGMENTING;329 return _augment;330 }331 332 template <typename Graph, typename Num, typename CapMap, typename FlowMap>333 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath2()334 {335 ResGW res_graph(*g, *capacity, *flow);336 bool _augment=false;337 338 if (status!=AFTER_FAST_AUGMENTING) {339 for (typename Graph::NodeIt n(*g); n!=INVALID; ++n) level.set(n, 0);340 number_of_augmentations=1;341 } else {342 ++number_of_augmentations;343 }344 TrickyReachedMap<ReachedMap>345 tricky_reached_map(level, number_of_augmentations);346 //ReachedMap level(res_graph);347 // FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);348 BfsIterator<ResGW, TrickyReachedMap<ReachedMap> >349 bfs(res_graph, tricky_reached_map);350 bfs.pushAndSetReached(s);351 352 typename ResGW::template NodeMap<ResGWEdge> pred(res_graph);353 pred.set(s, INVALID);354 355 typename ResGW::template NodeMap<Num> free(res_graph);356 357 //searching for augmenting path358 while ( !bfs.finished() ) {359 ResGWEdge e=bfs;360 if (e!=INVALID && bfs.isBNodeNewlyReached()) {361 Node v=res_graph.tail(e);362 Node w=res_graph.head(e);363 pred.set(w, e);364 if (pred[v]!=INVALID) {365 free.set(w, std::min(free[v], res_graph.resCap(e)));366 } else {367 free.set(w, res_graph.resCap(e));368 }369 if (res_graph.head(e)==t) { _augment=true; break; }370 }371 372 ++bfs;373 } //end of searching augmenting path374 375 if (_augment) {376 Node n=t;377 Num augment_value=free[t];378 while (pred[n]!=INVALID) {379 ResGWEdge e=pred[n];380 res_graph.augment(e, augment_value);381 n=res_graph.tail(e);382 }383 }384 385 status=AFTER_FAST_AUGMENTING;386 return _augment;387 }388 389 390 template <typename Graph, typename Num, typename CapMap, typename FlowMap>391 template<typename MutableGraph>392 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow()393 {394 typedef MutableGraph MG;395 bool _augment=false;396 397 ResGW res_graph(*g, *capacity, *flow);398 399 //bfs for distances on the residual graph400 //ReachedMap level(res_graph);401 for (typename Graph::NodeIt n(*g); n!=INVALID; ++n) level.set(n, 0);402 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);403 bfs.pushAndSetReached(s);404 typename ResGW::template NodeMap<int>405 dist(res_graph); //filled up with 0's406 407 //F will contain the physical copy of the residual graph408 //with the set of edges which are on shortest paths409 MG F;410 typename ResGW::template NodeMap<typename MG::Node>411 res_graph_to_F(res_graph);412 {413 typename ResGW::NodeIt n;414 for(res_graph.first(n); n!=INVALID; ++n)415 res_graph_to_F.set(n, F.addNode());416 }417 418 typename MG::Node sF=res_graph_to_F[s];419 typename MG::Node tF=res_graph_to_F[t];420 typename MG::template EdgeMap<ResGWEdge> original_edge(F);421 typename MG::template EdgeMap<Num> residual_capacity(F);422 423 while ( !bfs.finished() ) {424 ResGWEdge e=bfs;425 if (e!=INVALID) {426 if (bfs.isBNodeNewlyReached()) {427 dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1);428 typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)],429 res_graph_to_F[res_graph.head(e)]);430 //original_edge.update();431 original_edge.set(f, e);432 //residual_capacity.update();433 residual_capacity.set(f, res_graph.resCap(e));434 } else {435 if (dist[res_graph.head(e)]==(dist[res_graph.tail(e)]+1)) {436 typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)],437 res_graph_to_F[res_graph.head(e)]);438 //original_edge.update();439 original_edge.set(f, e);440 //residual_capacity.update();441 residual_capacity.set(f, res_graph.resCap(e));442 }443 }444 }445 ++bfs;446 } //computing distances from s in the residual graph447 448 bool __augment=true;449 450 while (__augment) {451 __augment=false;452 //computing blocking flow with dfs453 DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F);454 typename MG::template NodeMap<typename MG::Edge> pred(F);455 pred.set(sF, INVALID);456 //invalid iterators for sources457 458 typename MG::template NodeMap<Num> free(F);459 460 dfs.pushAndSetReached(sF);461 while (!dfs.finished()) {462 ++dfs;463 if (typename MG::Edge(dfs)!=INVALID) {464 if (dfs.isBNodeNewlyReached()) {465 typename MG::Node v=F.tail(dfs);466 typename MG::Node w=F.head(dfs);467 pred.set(w, dfs);468 if (pred[v]!=INVALID) {469 free.set(w, std::min(free[v], residual_capacity[dfs]));470 } else {471 free.set(w, residual_capacity[dfs]);472 }473 if (w==tF) {474 __augment=true;475 _augment=true;476 break;477 }478 479 } else {480 F.erase(typename MG::Edge(dfs));481 }482 }483 }484 485 if (__augment) {486 typename MG::Node n=tF;487 Num augment_value=free[tF];488 while (pred[n]!=INVALID) {489 typename MG::Edge e=pred[n];490 res_graph.augment(original_edge[e], augment_value);491 n=F.tail(e);492 if (residual_capacity[e]==augment_value)493 F.erase(e);494 else495 residual_capacity.set(e, residual_capacity[e]augment_value);496 }497 }498 499 }500 501 status=AFTER_AUGMENTING;502 return _augment;503 }504 505 /// Blocking flow augmentation without constructing the layered506 /// graph physically in which the blocking flow is computed.507 template <typename Graph, typename Num, typename CapMap, typename FlowMap>508 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2()509 {510 bool _augment=false;511 512 ResGW res_graph(*g, *capacity, *flow);513 514 //Potential map, for distances from s515 typename ResGW::template NodeMap<int> potential(res_graph, 0);516 typedef ConstMap<typename ResGW::Edge, int> Const1Map;517 Const1Map const_1_map(1);518 TightEdgeFilterMap<ResGW, typename ResGW::template NodeMap<int>,519 Const1Map> tight_edge_filter(res_graph, potential, const_1_map);520 521 for (typename Graph::NodeIt n(*g); n!=INVALID; ++n) level.set(n, 0);522 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);523 bfs.pushAndSetReached(s);524 525 //computing distances from s in the residual graph526 while ( !bfs.finished() ) {527 ResGWEdge e=bfs;528 if (e!=INVALID && bfs.isBNodeNewlyReached())529 potential.set(res_graph.head(e), potential[res_graph.tail(e)]+1);530 ++bfs;531 }532 533 //Subgraph containing the edges on some shortest paths534 //(i.e. tight edges)535 ConstMap<typename ResGW::Node, bool> true_map(true);536 typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>,537 TightEdgeFilterMap<ResGW, typename ResGW::template NodeMap<int>,538 Const1Map> > FilterResGW;539 FilterResGW filter_res_graph(res_graph, true_map, tight_edge_filter);540 541 //Subgraph, which is able to delete edges which are already542 //met by the dfs543 typename FilterResGW::template NodeMap<typename FilterResGW::Edge>544 first_out_edges(filter_res_graph);545 for (typename FilterResGW::NodeIt v(filter_res_graph); v!=INVALID; ++v)546 first_out_edges.set547 (v, typename FilterResGW::OutEdgeIt(filter_res_graph, v));548 549 typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW::550 template NodeMap<typename FilterResGW::Edge> > ErasingResGW;551 ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges);552 553 bool __augment=true;554 555 while (__augment) {556 557 __augment=false;558 //computing blocking flow with dfs559 DfsIterator< ErasingResGW,560 typename ErasingResGW::template NodeMap<bool> >561 dfs(erasing_res_graph);562 typename ErasingResGW::563 template NodeMap<typename ErasingResGW::Edge> pred(erasing_res_graph);564 pred.set(s, INVALID);565 //invalid iterators for sources566 567 typename ErasingResGW::template NodeMap<Num>568 free1(erasing_res_graph);569 570 dfs.pushAndSetReached571 /// \bug hugo 0.2572 (typename ErasingResGW::Node573 (typename FilterResGW::Node574 (typename ResGW::Node(s)575 )576 )577 );578 579 while (!dfs.finished()) {580 ++dfs;581 if (typename ErasingResGW::Edge(dfs)!=INVALID) {582 if (dfs.isBNodeNewlyReached()) {583 584 typename ErasingResGW::Node v=erasing_res_graph.tail(dfs);585 typename ErasingResGW::Node w=erasing_res_graph.head(dfs);586 587 pred.set(w, typename ErasingResGW::Edge(dfs));588 if (pred[v]!=INVALID) {589 free1.set590 (w, std::min(free1[v], res_graph.resCap591 (typename ErasingResGW::Edge(dfs))));592 } else {593 free1.set594 (w, res_graph.resCap595 (typename ErasingResGW::Edge(dfs)));596 }597 598 if (w==t) {599 __augment=true;600 _augment=true;601 break;602 }603 } else {604 erasing_res_graph.erase(dfs);605 }606 }607 }608 609 if (__augment) {610 typename ErasingResGW::Node611 n=typename FilterResGW::Node(typename ResGW::Node(t));612 Num augment_value=free1[n];613 while (pred[n]!=INVALID) {614 typename ErasingResGW::Edge e=pred[n];615 res_graph.augment(e, augment_value);616 n=erasing_res_graph.tail(e);617 if (res_graph.resCap(e)==0)618 erasing_res_graph.erase(e);619 }620 }621 622 } //while (__augment)623 624 status=AFTER_AUGMENTING;625 return _augment;626 }627 628 629 } //namespace hugo630 631 #endif //HUGO_AUGMENTING_FLOW_H632 633
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