Changeset 358:7f26c4b32651 in lemon for lemon
 Timestamp:
 10/28/08 23:10:27 (16 years ago)
 Branch:
 default
 Phase:
 public
 File:

 1 edited
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lemon/suurballe.h
r357 r358 34 34 /// @{ 35 35 36 /// \brief Implementation of an algorithm for finding arcdisjoint37 /// paths between two nodeshaving minimum total length.36 /// \brief Algorithm for finding arcdisjoint paths between two nodes 37 /// having minimum total length. 38 38 /// 39 39 /// \ref lemon::Suurballe "Suurballe" implements an algorithm for 40 40 /// finding arcdisjoint paths having minimum total length (cost) 41 /// from a given source node to a given target node in a directed 42 /// digraph. 41 /// from a given source node to a given target node in a digraph. 43 42 /// 44 43 /// In fact, this implementation is the specialization of the 45 44 /// \ref CapacityScaling "successive shortest path" algorithm. 46 45 /// 47 /// \tparam Digraph The directed digraph type the algorithm runs on. 46 /// \tparam Digraph The digraph type the algorithm runs on. 47 /// The default value is \c ListDigraph. 48 48 /// \tparam LengthMap The type of the length (cost) map. 49 /// The default value is <tt>Digraph::ArcMap<int></tt>. 49 50 /// 50 51 /// \warning Length values should be \e nonnegative \e integers. … … 52 53 /// \note For finding nodedisjoint paths this algorithm can be used 53 54 /// with \ref SplitDigraphAdaptor. 54 /// 55 /// \author Attila Bernath and Peter Kovacs56 57 template < typename Digraph ,55 #ifdef DOXYGEN 56 template <typename Digraph, typename LengthMap> 57 #else 58 template < typename Digraph = ListDigraph, 58 59 typename LengthMap = typename Digraph::template ArcMap<int> > 60 #endif 59 61 class Suurballe 60 62 { … … 76 78 private: 77 79 78 /// \brief Special implementation of the \refDijkstra algorithm80 /// \brief Special implementation of the Dijkstra algorithm 79 81 /// for finding shortest paths in the residual network. 80 82 /// … … 91 93 private: 92 94 93 // The di rected digraph the algorithm runs on95 // The digraph the algorithm runs on 94 96 const Digraph &_graph; 95 97 … … 121 123 _dist(digraph), _pred(pred), _s(s), _t(t) {} 122 124 123 /// \brief Run s the algorithm. Returns \c true if a path is found125 /// \brief Run the algorithm. It returns \c true if a path is found 124 126 /// from the source node to the target node. 125 127 bool run() { … … 130 132 _proc_nodes.clear(); 131 133 132 // Process ingnodes134 // Process nodes 133 135 while (!heap.empty() && heap.top() != _t) { 134 136 Node u = heap.top(), v; … … 138 140 _proc_nodes.push_back(u); 139 141 140 // Travers ingoutgoing arcs142 // Traverse outgoing arcs 141 143 for (OutArcIt e(_graph, u); e != INVALID; ++e) { 142 144 if (_flow[e] == 0) { … … 160 162 } 161 163 162 // Travers ingincoming arcs164 // Traverse incoming arcs 163 165 for (InArcIt e(_graph, u); e != INVALID; ++e) { 164 166 if (_flow[e] == 1) { … … 184 186 if (heap.empty()) return false; 185 187 186 // Updat ingpotentials of processed nodes188 // Update potentials of processed nodes 187 189 Length t_dist = heap.prio(); 188 190 for (int i = 0; i < int(_proc_nodes.size()); ++i) … … 195 197 private: 196 198 197 // The di rected digraph the algorithm runs on199 // The digraph the algorithm runs on 198 200 const Digraph &_graph; 199 201 // The length map … … 228 230 /// Constructor. 229 231 /// 230 /// \param digraph The di rected digraph the algorithm runs on.232 /// \param digraph The digraph the algorithm runs on. 231 233 /// \param length The length (cost) values of the arcs. 232 234 /// \param s The source node. … … 246 248 } 247 249 248 /// \brief Set sthe flow map.249 /// 250 /// Sets the flow map.250 /// \brief Set the flow map. 251 /// 252 /// This function sets the flow map. 251 253 /// 252 254 /// The found flow contains only 0 and 1 values. It is the union of … … 263 265 } 264 266 265 /// \brief Set sthe potential map.266 /// 267 /// Sets the potential map.267 /// \brief Set the potential map. 268 /// 269 /// This function sets the potential map. 268 270 /// 269 271 /// The potentials provide the dual solution of the underlying … … 289 291 /// @{ 290 292 291 /// \brief Run sthe algorithm.292 /// 293 /// Runs the algorithm.293 /// \brief Run the algorithm. 294 /// 295 /// This function runs the algorithm. 294 296 /// 295 297 /// \param k The number of paths to be found. 296 298 /// 297 /// \return \c k if there are at least \c k arcdisjoint paths 298 /// from \c s to \c t. Otherwise it returns the number of299 /// \return \c k if there are at least \c k arcdisjoint paths from 300 /// \c s to \c t in the digraph. Otherwise it returns the number of 299 301 /// arcdisjoint paths found. 300 302 /// … … 313 315 } 314 316 315 /// \brief Initialize sthe algorithm.316 /// 317 /// Initializes the algorithm.317 /// \brief Initialize the algorithm. 318 /// 319 /// This function initializes the algorithm. 318 320 void init() { 319 // Initializ ingmaps321 // Initialize maps 320 322 if (!_flow) { 321 323 _flow = new FlowMap(_graph); … … 334 336 } 335 337 336 /// \brief Execute sthe successive shortest path algorithm to find338 /// \brief Execute the successive shortest path algorithm to find 337 339 /// an optimal flow. 338 340 /// 339 /// Executes the successive shortest path algorithm to find a340 /// minimum cost flow, which is the union of \c k or less341 /// This function executes the successive shortest path algorithm to 342 /// find a minimum cost flow, which is the union of \c k or less 341 343 /// arcdisjoint paths. 342 344 /// 343 /// \return \c k if there are at least \c k arcdisjoint paths 344 /// from \c s to \c t. Otherwise it returns the number of345 /// \return \c k if there are at least \c k arcdisjoint paths from 346 /// \c s to \c t in the digraph. Otherwise it returns the number of 345 347 /// arcdisjoint paths found. 346 348 /// 347 349 /// \pre \ref init() must be called before using this function. 348 350 int findFlow(int k = 2) { 349 // Find ingshortest paths351 // Find shortest paths 350 352 _path_num = 0; 351 353 while (_path_num < k) { 352 // Run ningDijkstra354 // Run Dijkstra 353 355 if (!_dijkstra>run()) break; 354 356 ++_path_num; 355 357 356 // Set tingthe flow along the found shortest path358 // Set the flow along the found shortest path 357 359 Node u = _target; 358 360 Arc e; … … 370 372 } 371 373 372 /// \brief Compute sthe paths from the flow.373 /// 374 /// Computes the paths from the flow.374 /// \brief Compute the paths from the flow. 375 /// 376 /// This function computes the paths from the flow. 375 377 /// 376 378 /// \pre \ref init() and \ref findFlow() must be called before using 377 379 /// this function. 378 380 void findPaths() { 379 // Creat ing the residual flow map (the union of the paths not380 // foundso far)381 // Create the residual flow map (the union of the paths not found 382 // so far) 381 383 FlowMap res_flow(_graph); 382 for(ArcIt a(_graph); a!=INVALID;++a) res_flow[a]=(*_flow)[a];384 for(ArcIt a(_graph); a != INVALID; ++a) res_flow[a] = (*_flow)[a]; 383 385 384 386 paths.clear(); … … 399 401 400 402 /// \name Query Functions 401 /// The result of the algorithm can be obtained using these403 /// The results of the algorithm can be obtained using these 402 404 /// functions. 403 405 /// \n The algorithm should be executed before using them. … … 405 407 /// @{ 406 408 407 /// \brief Return sa const reference to the arc map storing the409 /// \brief Return a const reference to the arc map storing the 408 410 /// found flow. 409 411 /// 410 /// Returns a const reference to the arc map storing the flow that411 /// is the union of the found arcdisjoint paths.412 /// 413 /// \pre \ref run() or findFlow() must be called before using this414 /// function.412 /// This function returns a const reference to the arc map storing 413 /// the flow that is the union of the found arcdisjoint paths. 414 /// 415 /// \pre \ref run() or \ref findFlow() must be called before using 416 /// this function. 415 417 const FlowMap& flowMap() const { 416 418 return *_flow; 417 419 } 418 420 419 /// \brief Return sa const reference to the node map storing the421 /// \brief Return a const reference to the node map storing the 420 422 /// found potentials (the dual solution). 421 423 /// 422 /// Returns a const reference to the node map storing the found423 /// potentials that provide the dual solution of the underlying424 /// minimum cost flow problem.425 /// 426 /// \pre \ref run() or findFlow() must be called before using this427 /// function.424 /// This function returns a const reference to the node map storing 425 /// the found potentials that provide the dual solution of the 426 /// underlying minimum cost flow problem. 427 /// 428 /// \pre \ref run() or \ref findFlow() must be called before using 429 /// this function. 428 430 const PotentialMap& potentialMap() const { 429 431 return *_potential; 430 432 } 431 433 432 /// \brief Return sthe flow on the given arc.433 /// 434 /// Returns the flow on the given arc.434 /// \brief Return the flow on the given arc. 435 /// 436 /// This function returns the flow on the given arc. 435 437 /// It is \c 1 if the arc is involved in one of the found paths, 436 438 /// otherwise it is \c 0. 437 439 /// 438 /// \pre \ref run() or findFlow() must be called before using this439 /// function.440 /// \pre \ref run() or \ref findFlow() must be called before using 441 /// this function. 440 442 int flow(const Arc& arc) const { 441 443 return (*_flow)[arc]; 442 444 } 443 445 444 /// \brief Return sthe potential of the given node.445 /// 446 /// Returns the potential of the given node.447 /// 448 /// \pre \ref run() or findFlow() must be called before using this449 /// function.446 /// \brief Return the potential of the given node. 447 /// 448 /// This function returns the potential of the given node. 449 /// 450 /// \pre \ref run() or \ref findFlow() must be called before using 451 /// this function. 450 452 Length potential(const Node& node) const { 451 453 return (*_potential)[node]; 452 454 } 453 455 454 /// \brief Return sthe total length (cost) of the found paths (flow).455 /// 456 /// Returns the total length (cost) of the found paths (flow).457 /// The complexity of the function is \f$ O(e) \f$.458 /// 459 /// \pre \ref run() or findFlow() must be called before using this460 /// function.456 /// \brief Return the total length (cost) of the found paths (flow). 457 /// 458 /// This function returns the total length (cost) of the found paths 459 /// (flow). The complexity of the function is \f$ O(e) \f$. 460 /// 461 /// \pre \ref run() or \ref findFlow() must be called before using 462 /// this function. 461 463 Length totalLength() const { 462 464 Length c = 0; … … 466 468 } 467 469 468 /// \brief Return sthe number of the found paths.469 /// 470 /// Returns the number of the found paths.471 /// 472 /// \pre \ref run() or findFlow() must be called before using this473 /// function.470 /// \brief Return the number of the found paths. 471 /// 472 /// This function returns the number of the found paths. 473 /// 474 /// \pre \ref run() or \ref findFlow() must be called before using 475 /// this function. 474 476 int pathNum() const { 475 477 return _path_num; 476 478 } 477 479 478 /// \brief Return sa const reference to the specified path.479 /// 480 /// Returns a const reference to the specified path.480 /// \brief Return a const reference to the specified path. 481 /// 482 /// This function returns a const reference to the specified path. 481 483 /// 482 484 /// \param i The function returns the \c ith path. 483 485 /// \c i must be between \c 0 and <tt>%pathNum()1</tt>. 484 486 /// 485 /// \pre \ref run() or findPaths() must be called before using this486 /// function.487 /// \pre \ref run() or \ref findPaths() must be called before using 488 /// this function. 487 489 Path path(int i) const { 488 490 return paths[i];
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