0
3
0
| 1 | 1 |
/* -*- mode: C++; indent-tabs-mode: nil; -*- |
| 2 | 2 |
* |
| 3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library. |
| 4 | 4 |
* |
| 5 | 5 |
* Copyright (C) 2003-2008 |
| 6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
| 7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
| 8 | 8 |
* |
| 9 | 9 |
* Permission to use, modify and distribute this software is granted |
| 10 | 10 |
* provided that this copyright notice appears in all copies. For |
| 11 | 11 |
* precise terms see the accompanying LICENSE file. |
| 12 | 12 |
* |
| 13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
| 14 | 14 |
* express or implied, and with no claim as to its suitability for any |
| 15 | 15 |
* purpose. |
| 16 | 16 |
* |
| 17 | 17 |
*/ |
| 18 | 18 |
|
| 19 | 19 |
#ifndef LEMON_CONNECTIVITY_H |
| 20 | 20 |
#define LEMON_CONNECTIVITY_H |
| 21 | 21 |
|
| 22 | 22 |
#include <lemon/dfs.h> |
| 23 | 23 |
#include <lemon/bfs.h> |
| 24 | 24 |
#include <lemon/core.h> |
| 25 | 25 |
#include <lemon/maps.h> |
| 26 | 26 |
#include <lemon/adaptors.h> |
| 27 | 27 |
|
| 28 | 28 |
#include <lemon/concepts/digraph.h> |
| 29 | 29 |
#include <lemon/concepts/graph.h> |
| 30 | 30 |
#include <lemon/concept_check.h> |
| 31 | 31 |
|
| 32 | 32 |
#include <stack> |
| 33 | 33 |
#include <functional> |
| 34 | 34 |
|
| 35 | 35 |
/// \ingroup connectivity |
| 36 | 36 |
/// \file |
| 37 | 37 |
/// \brief Connectivity algorithms |
| 38 | 38 |
/// |
| 39 | 39 |
/// Connectivity algorithms |
| 40 | 40 |
|
| 41 | 41 |
namespace lemon {
|
| 42 | 42 |
|
| 43 | 43 |
/// \ingroup connectivity |
| 44 | 44 |
/// |
| 45 | 45 |
/// \brief Check whether the given undirected graph is connected. |
| 46 | 46 |
/// |
| 47 | 47 |
/// Check whether the given undirected graph is connected. |
| 48 | 48 |
/// \param graph The undirected graph. |
| 49 | 49 |
/// \return %True when there is path between any two nodes in the graph. |
| 50 | 50 |
/// \note By definition, the empty graph is connected. |
| 51 | 51 |
template <typename Graph> |
| 52 | 52 |
bool connected(const Graph& graph) {
|
| 53 | 53 |
checkConcept<concepts::Graph, Graph>(); |
| 54 | 54 |
typedef typename Graph::NodeIt NodeIt; |
| 55 | 55 |
if (NodeIt(graph) == INVALID) return true; |
| 56 | 56 |
Dfs<Graph> dfs(graph); |
| 57 | 57 |
dfs.run(NodeIt(graph)); |
| 58 | 58 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 59 | 59 |
if (!dfs.reached(it)) {
|
| 60 | 60 |
return false; |
| 61 | 61 |
} |
| 62 | 62 |
} |
| 63 | 63 |
return true; |
| 64 | 64 |
} |
| 65 | 65 |
|
| 66 | 66 |
/// \ingroup connectivity |
| 67 | 67 |
/// |
| 68 | 68 |
/// \brief Count the number of connected components of an undirected graph |
| 69 | 69 |
/// |
| 70 | 70 |
/// Count the number of connected components of an undirected graph |
| 71 | 71 |
/// |
| 72 | 72 |
/// \param graph The graph. It must be undirected. |
| 73 | 73 |
/// \return The number of components |
| 74 | 74 |
/// \note By definition, the empty graph consists |
| 75 | 75 |
/// of zero connected components. |
| 76 | 76 |
template <typename Graph> |
| 77 | 77 |
int countConnectedComponents(const Graph &graph) {
|
| 78 | 78 |
checkConcept<concepts::Graph, Graph>(); |
| 79 | 79 |
typedef typename Graph::Node Node; |
| 80 | 80 |
typedef typename Graph::Arc Arc; |
| 81 | 81 |
|
| 82 | 82 |
typedef NullMap<Node, Arc> PredMap; |
| 83 | 83 |
typedef NullMap<Node, int> DistMap; |
| 84 | 84 |
|
| 85 | 85 |
int compNum = 0; |
| 86 | 86 |
typename Bfs<Graph>:: |
| 87 | 87 |
template SetPredMap<PredMap>:: |
| 88 | 88 |
template SetDistMap<DistMap>:: |
| 89 | 89 |
Create bfs(graph); |
| 90 | 90 |
|
| 91 | 91 |
PredMap predMap; |
| 92 | 92 |
bfs.predMap(predMap); |
| 93 | 93 |
|
| 94 | 94 |
DistMap distMap; |
| 95 | 95 |
bfs.distMap(distMap); |
| 96 | 96 |
|
| 97 | 97 |
bfs.init(); |
| 98 | 98 |
for(typename Graph::NodeIt n(graph); n != INVALID; ++n) {
|
| 99 | 99 |
if (!bfs.reached(n)) {
|
| 100 | 100 |
bfs.addSource(n); |
| 101 | 101 |
bfs.start(); |
| 102 | 102 |
++compNum; |
| 103 | 103 |
} |
| 104 | 104 |
} |
| 105 | 105 |
return compNum; |
| 106 | 106 |
} |
| 107 | 107 |
|
| 108 | 108 |
/// \ingroup connectivity |
| 109 | 109 |
/// |
| 110 | 110 |
/// \brief Find the connected components of an undirected graph |
| 111 | 111 |
/// |
| 112 | 112 |
/// Find the connected components of an undirected graph. |
| 113 | 113 |
/// |
| 114 | 114 |
/// \param graph The graph. It must be undirected. |
| 115 | 115 |
/// \retval compMap A writable node map. The values will be set from 0 to |
| 116 | 116 |
/// the number of the connected components minus one. Each values of the map |
| 117 | 117 |
/// will be set exactly once, the values of a certain component will be |
| 118 | 118 |
/// set continuously. |
| 119 | 119 |
/// \return The number of components |
| 120 | 120 |
/// |
| 121 | 121 |
template <class Graph, class NodeMap> |
| 122 | 122 |
int connectedComponents(const Graph &graph, NodeMap &compMap) {
|
| 123 | 123 |
checkConcept<concepts::Graph, Graph>(); |
| 124 | 124 |
typedef typename Graph::Node Node; |
| 125 | 125 |
typedef typename Graph::Arc Arc; |
| 126 | 126 |
checkConcept<concepts::WriteMap<Node, int>, NodeMap>(); |
| 127 | 127 |
|
| 128 | 128 |
typedef NullMap<Node, Arc> PredMap; |
| 129 | 129 |
typedef NullMap<Node, int> DistMap; |
| 130 | 130 |
|
| 131 | 131 |
int compNum = 0; |
| 132 | 132 |
typename Bfs<Graph>:: |
| 133 | 133 |
template SetPredMap<PredMap>:: |
| 134 | 134 |
template SetDistMap<DistMap>:: |
| 135 | 135 |
Create bfs(graph); |
| 136 | 136 |
|
| 137 | 137 |
PredMap predMap; |
| 138 | 138 |
bfs.predMap(predMap); |
| 139 | 139 |
|
| 140 | 140 |
DistMap distMap; |
| 141 | 141 |
bfs.distMap(distMap); |
| 142 | 142 |
|
| 143 | 143 |
bfs.init(); |
| 144 | 144 |
for(typename Graph::NodeIt n(graph); n != INVALID; ++n) {
|
| 145 | 145 |
if(!bfs.reached(n)) {
|
| 146 | 146 |
bfs.addSource(n); |
| 147 | 147 |
while (!bfs.emptyQueue()) {
|
| 148 | 148 |
compMap.set(bfs.nextNode(), compNum); |
| 149 | 149 |
bfs.processNextNode(); |
| 150 | 150 |
} |
| 151 | 151 |
++compNum; |
| 152 | 152 |
} |
| 153 | 153 |
} |
| 154 | 154 |
return compNum; |
| 155 | 155 |
} |
| 156 | 156 |
|
| 157 | 157 |
namespace _connectivity_bits {
|
| 158 | 158 |
|
| 159 | 159 |
template <typename Digraph, typename Iterator > |
| 160 | 160 |
struct LeaveOrderVisitor : public DfsVisitor<Digraph> {
|
| 161 | 161 |
public: |
| 162 | 162 |
typedef typename Digraph::Node Node; |
| 163 | 163 |
LeaveOrderVisitor(Iterator it) : _it(it) {}
|
| 164 | 164 |
|
| 165 | 165 |
void leave(const Node& node) {
|
| 166 | 166 |
*(_it++) = node; |
| 167 | 167 |
} |
| 168 | 168 |
|
| 169 | 169 |
private: |
| 170 | 170 |
Iterator _it; |
| 171 | 171 |
}; |
| 172 | 172 |
|
| 173 | 173 |
template <typename Digraph, typename Map> |
| 174 | 174 |
struct FillMapVisitor : public DfsVisitor<Digraph> {
|
| 175 | 175 |
public: |
| 176 | 176 |
typedef typename Digraph::Node Node; |
| 177 | 177 |
typedef typename Map::Value Value; |
| 178 | 178 |
|
| 179 | 179 |
FillMapVisitor(Map& map, Value& value) |
| 180 | 180 |
: _map(map), _value(value) {}
|
| 181 | 181 |
|
| 182 | 182 |
void reach(const Node& node) {
|
| 183 | 183 |
_map.set(node, _value); |
| 184 | 184 |
} |
| 185 | 185 |
private: |
| 186 | 186 |
Map& _map; |
| 187 | 187 |
Value& _value; |
| 188 | 188 |
}; |
| 189 | 189 |
|
| 190 | 190 |
template <typename Digraph, typename ArcMap> |
| 191 | 191 |
struct StronglyConnectedCutArcsVisitor : public DfsVisitor<Digraph> {
|
| 192 | 192 |
public: |
| 193 | 193 |
typedef typename Digraph::Node Node; |
| 194 | 194 |
typedef typename Digraph::Arc Arc; |
| 195 | 195 |
|
| 196 | 196 |
StronglyConnectedCutArcsVisitor(const Digraph& digraph, |
| 197 | 197 |
ArcMap& cutMap, |
| 198 | 198 |
int& cutNum) |
| 199 | 199 |
: _digraph(digraph), _cutMap(cutMap), _cutNum(cutNum), |
| 200 | 200 |
_compMap(digraph, -1), _num(-1) {
|
| 201 | 201 |
} |
| 202 | 202 |
|
| 203 | 203 |
void start(const Node&) {
|
| 204 | 204 |
++_num; |
| 205 | 205 |
} |
| 206 | 206 |
|
| 207 | 207 |
void reach(const Node& node) {
|
| 208 | 208 |
_compMap.set(node, _num); |
| 209 | 209 |
} |
| 210 | 210 |
|
| 211 | 211 |
void examine(const Arc& arc) {
|
| 212 | 212 |
if (_compMap[_digraph.source(arc)] != |
| 213 | 213 |
_compMap[_digraph.target(arc)]) {
|
| 214 | 214 |
_cutMap.set(arc, true); |
| 215 | 215 |
++_cutNum; |
| 216 | 216 |
} |
| 217 | 217 |
} |
| 218 | 218 |
private: |
| 219 | 219 |
const Digraph& _digraph; |
| 220 | 220 |
ArcMap& _cutMap; |
| 221 | 221 |
int& _cutNum; |
| 222 | 222 |
|
| 223 | 223 |
typename Digraph::template NodeMap<int> _compMap; |
| 224 | 224 |
int _num; |
| 225 | 225 |
}; |
| 226 | 226 |
|
| 227 | 227 |
} |
| 228 | 228 |
|
| 229 | 229 |
|
| 230 | 230 |
/// \ingroup connectivity |
| 231 | 231 |
/// |
| 232 | 232 |
/// \brief Check whether the given directed graph is strongly connected. |
| 233 | 233 |
/// |
| 234 | 234 |
/// Check whether the given directed graph is strongly connected. The |
| 235 | 235 |
/// graph is strongly connected when any two nodes of the graph are |
| 236 | 236 |
/// connected with directed paths in both direction. |
| 237 | 237 |
/// \return %False when the graph is not strongly connected. |
| 238 | 238 |
/// \see connected |
| 239 | 239 |
/// |
| 240 | 240 |
/// \note By definition, the empty graph is strongly connected. |
| 241 | 241 |
template <typename Digraph> |
| 242 | 242 |
bool stronglyConnected(const Digraph& digraph) {
|
| 243 | 243 |
checkConcept<concepts::Digraph, Digraph>(); |
| 244 | 244 |
|
| 245 | 245 |
typedef typename Digraph::Node Node; |
| 246 | 246 |
typedef typename Digraph::NodeIt NodeIt; |
| 247 | 247 |
|
| 248 | 248 |
typename Digraph::Node source = NodeIt(digraph); |
| 249 | 249 |
if (source == INVALID) return true; |
| 250 | 250 |
|
| 251 | 251 |
using namespace _connectivity_bits; |
| 252 | 252 |
|
| 253 | 253 |
typedef DfsVisitor<Digraph> Visitor; |
| 254 | 254 |
Visitor visitor; |
| 255 | 255 |
|
| 256 | 256 |
DfsVisit<Digraph, Visitor> dfs(digraph, visitor); |
| 257 | 257 |
dfs.init(); |
| 258 | 258 |
dfs.addSource(source); |
| 259 | 259 |
dfs.start(); |
| 260 | 260 |
|
| 261 | 261 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 262 | 262 |
if (!dfs.reached(it)) {
|
| 263 | 263 |
return false; |
| 264 | 264 |
} |
| 265 | 265 |
} |
| 266 | 266 |
|
| 267 | 267 |
typedef ReverseDigraph<const Digraph> RDigraph; |
| 268 | 268 |
typedef typename RDigraph::NodeIt RNodeIt; |
| 269 | 269 |
RDigraph rdigraph(digraph); |
| 270 | 270 |
|
| 271 | 271 |
typedef DfsVisitor<Digraph> RVisitor; |
| 272 | 272 |
RVisitor rvisitor; |
| 273 | 273 |
|
| 274 | 274 |
DfsVisit<RDigraph, RVisitor> rdfs(rdigraph, rvisitor); |
| 275 | 275 |
rdfs.init(); |
| 276 | 276 |
rdfs.addSource(source); |
| 277 | 277 |
rdfs.start(); |
| 278 | 278 |
|
| 279 | 279 |
for (RNodeIt it(rdigraph); it != INVALID; ++it) {
|
| 280 | 280 |
if (!rdfs.reached(it)) {
|
| 281 | 281 |
return false; |
| 282 | 282 |
} |
| 283 | 283 |
} |
| 284 | 284 |
|
| 285 | 285 |
return true; |
| 286 | 286 |
} |
| 287 | 287 |
|
| 288 | 288 |
/// \ingroup connectivity |
| 289 | 289 |
/// |
| 290 | 290 |
/// \brief Count the strongly connected components of a directed graph |
| 291 | 291 |
/// |
| 292 | 292 |
/// Count the strongly connected components of a directed graph. |
| 293 | 293 |
/// The strongly connected components are the classes of an |
| 294 | 294 |
/// equivalence relation on the nodes of the graph. Two nodes are in |
| 295 | 295 |
/// the same class if they are connected with directed paths in both |
| 296 | 296 |
/// direction. |
| 297 | 297 |
/// |
| 298 |
/// \param |
|
| 298 |
/// \param digraph The graph. |
|
| 299 | 299 |
/// \return The number of components |
| 300 | 300 |
/// \note By definition, the empty graph has zero |
| 301 | 301 |
/// strongly connected components. |
| 302 | 302 |
template <typename Digraph> |
| 303 | 303 |
int countStronglyConnectedComponents(const Digraph& digraph) {
|
| 304 | 304 |
checkConcept<concepts::Digraph, Digraph>(); |
| 305 | 305 |
|
| 306 | 306 |
using namespace _connectivity_bits; |
| 307 | 307 |
|
| 308 | 308 |
typedef typename Digraph::Node Node; |
| 309 | 309 |
typedef typename Digraph::Arc Arc; |
| 310 | 310 |
typedef typename Digraph::NodeIt NodeIt; |
| 311 | 311 |
typedef typename Digraph::ArcIt ArcIt; |
| 312 | 312 |
|
| 313 | 313 |
typedef std::vector<Node> Container; |
| 314 | 314 |
typedef typename Container::iterator Iterator; |
| 315 | 315 |
|
| 316 | 316 |
Container nodes(countNodes(digraph)); |
| 317 | 317 |
typedef LeaveOrderVisitor<Digraph, Iterator> Visitor; |
| 318 | 318 |
Visitor visitor(nodes.begin()); |
| 319 | 319 |
|
| 320 | 320 |
DfsVisit<Digraph, Visitor> dfs(digraph, visitor); |
| 321 | 321 |
dfs.init(); |
| 322 | 322 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 323 | 323 |
if (!dfs.reached(it)) {
|
| 324 | 324 |
dfs.addSource(it); |
| 325 | 325 |
dfs.start(); |
| 326 | 326 |
} |
| 327 | 327 |
} |
| 328 | 328 |
|
| 329 | 329 |
typedef typename Container::reverse_iterator RIterator; |
| 330 | 330 |
typedef ReverseDigraph<const Digraph> RDigraph; |
| 331 | 331 |
|
| 332 | 332 |
RDigraph rdigraph(digraph); |
| 333 | 333 |
|
| 334 | 334 |
typedef DfsVisitor<Digraph> RVisitor; |
| 335 | 335 |
RVisitor rvisitor; |
| 336 | 336 |
|
| 337 | 337 |
DfsVisit<RDigraph, RVisitor> rdfs(rdigraph, rvisitor); |
| 338 | 338 |
|
| 339 | 339 |
int compNum = 0; |
| 340 | 340 |
|
| 341 | 341 |
rdfs.init(); |
| 342 | 342 |
for (RIterator it = nodes.rbegin(); it != nodes.rend(); ++it) {
|
| 343 | 343 |
if (!rdfs.reached(*it)) {
|
| 344 | 344 |
rdfs.addSource(*it); |
| 345 | 345 |
rdfs.start(); |
| 346 | 346 |
++compNum; |
| 347 | 347 |
} |
| 348 | 348 |
} |
| 349 | 349 |
return compNum; |
| 350 | 350 |
} |
| 351 | 351 |
|
| 352 | 352 |
/// \ingroup connectivity |
| 353 | 353 |
/// |
| 354 | 354 |
/// \brief Find the strongly connected components of a directed graph |
| 355 | 355 |
/// |
| 356 | 356 |
/// Find the strongly connected components of a directed graph. The |
| 357 | 357 |
/// strongly connected components are the classes of an equivalence |
| 358 | 358 |
/// relation on the nodes of the graph. Two nodes are in |
| 359 | 359 |
/// relationship when there are directed paths between them in both |
| 360 | 360 |
/// direction. In addition, the numbering of components will satisfy |
| 361 | 361 |
/// that there is no arc going from a higher numbered component to |
| 362 | 362 |
/// a lower. |
| 363 | 363 |
/// |
| 364 | 364 |
/// \param digraph The digraph. |
| 365 | 365 |
/// \retval compMap A writable node map. The values will be set from 0 to |
| 366 | 366 |
/// the number of the strongly connected components minus one. Each value |
| 367 | 367 |
/// of the map will be set exactly once, the values of a certain component |
| 368 | 368 |
/// will be set continuously. |
| 369 | 369 |
/// \return The number of components |
| 370 | 370 |
/// |
| 371 | 371 |
template <typename Digraph, typename NodeMap> |
| 372 | 372 |
int stronglyConnectedComponents(const Digraph& digraph, NodeMap& compMap) {
|
| 373 | 373 |
checkConcept<concepts::Digraph, Digraph>(); |
| 374 | 374 |
typedef typename Digraph::Node Node; |
| 375 | 375 |
typedef typename Digraph::NodeIt NodeIt; |
| 376 | 376 |
checkConcept<concepts::WriteMap<Node, int>, NodeMap>(); |
| 377 | 377 |
|
| 378 | 378 |
using namespace _connectivity_bits; |
| 379 | 379 |
|
| 380 | 380 |
typedef std::vector<Node> Container; |
| 381 | 381 |
typedef typename Container::iterator Iterator; |
| 382 | 382 |
|
| 383 | 383 |
Container nodes(countNodes(digraph)); |
| 384 | 384 |
typedef LeaveOrderVisitor<Digraph, Iterator> Visitor; |
| 385 | 385 |
Visitor visitor(nodes.begin()); |
| 386 | 386 |
|
| 387 | 387 |
DfsVisit<Digraph, Visitor> dfs(digraph, visitor); |
| 388 | 388 |
dfs.init(); |
| 389 | 389 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 390 | 390 |
if (!dfs.reached(it)) {
|
| 391 | 391 |
dfs.addSource(it); |
| 392 | 392 |
dfs.start(); |
| 393 | 393 |
} |
| 394 | 394 |
} |
| 395 | 395 |
|
| 396 | 396 |
typedef typename Container::reverse_iterator RIterator; |
| 397 | 397 |
typedef ReverseDigraph<const Digraph> RDigraph; |
| 398 | 398 |
|
| 399 | 399 |
RDigraph rdigraph(digraph); |
| 400 | 400 |
|
| 401 | 401 |
int compNum = 0; |
| 402 | 402 |
|
| 403 | 403 |
typedef FillMapVisitor<RDigraph, NodeMap> RVisitor; |
| 404 | 404 |
RVisitor rvisitor(compMap, compNum); |
| 405 | 405 |
|
| 406 | 406 |
DfsVisit<RDigraph, RVisitor> rdfs(rdigraph, rvisitor); |
| 407 | 407 |
|
| 408 | 408 |
rdfs.init(); |
| 409 | 409 |
for (RIterator it = nodes.rbegin(); it != nodes.rend(); ++it) {
|
| 410 | 410 |
if (!rdfs.reached(*it)) {
|
| 411 | 411 |
rdfs.addSource(*it); |
| 412 | 412 |
rdfs.start(); |
| 413 | 413 |
++compNum; |
| 414 | 414 |
} |
| 415 | 415 |
} |
| 416 | 416 |
return compNum; |
| 417 | 417 |
} |
| 418 | 418 |
|
| 419 | 419 |
/// \ingroup connectivity |
| 420 | 420 |
/// |
| 421 | 421 |
/// \brief Find the cut arcs of the strongly connected components. |
| 422 | 422 |
/// |
| 423 | 423 |
/// Find the cut arcs of the strongly connected components. |
| 424 | 424 |
/// The strongly connected components are the classes of an equivalence |
| 425 | 425 |
/// relation on the nodes of the graph. Two nodes are in relationship |
| 426 | 426 |
/// when there are directed paths between them in both direction. |
| 427 | 427 |
/// The strongly connected components are separated by the cut arcs. |
| 428 | 428 |
/// |
| 429 | 429 |
/// \param graph The graph. |
| 430 | 430 |
/// \retval cutMap A writable node map. The values will be set true when the |
| 431 | 431 |
/// arc is a cut arc. |
| 432 | 432 |
/// |
| 433 | 433 |
/// \return The number of cut arcs |
| 434 | 434 |
template <typename Digraph, typename ArcMap> |
| 435 | 435 |
int stronglyConnectedCutArcs(const Digraph& graph, ArcMap& cutMap) {
|
| 436 | 436 |
checkConcept<concepts::Digraph, Digraph>(); |
| 437 | 437 |
typedef typename Digraph::Node Node; |
| 438 | 438 |
typedef typename Digraph::Arc Arc; |
| 439 | 439 |
typedef typename Digraph::NodeIt NodeIt; |
| 440 | 440 |
checkConcept<concepts::WriteMap<Arc, bool>, ArcMap>(); |
| 441 | 441 |
|
| 442 | 442 |
using namespace _connectivity_bits; |
| 443 | 443 |
|
| 444 | 444 |
typedef std::vector<Node> Container; |
| 445 | 445 |
typedef typename Container::iterator Iterator; |
| 446 | 446 |
|
| 447 | 447 |
Container nodes(countNodes(graph)); |
| 448 | 448 |
typedef LeaveOrderVisitor<Digraph, Iterator> Visitor; |
| 449 | 449 |
Visitor visitor(nodes.begin()); |
| 450 | 450 |
|
| 451 | 451 |
DfsVisit<Digraph, Visitor> dfs(graph, visitor); |
| 452 | 452 |
dfs.init(); |
| 453 | 453 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 454 | 454 |
if (!dfs.reached(it)) {
|
| 455 | 455 |
dfs.addSource(it); |
| 456 | 456 |
dfs.start(); |
| 457 | 457 |
} |
| 458 | 458 |
} |
| 459 | 459 |
|
| 460 | 460 |
typedef typename Container::reverse_iterator RIterator; |
| 461 | 461 |
typedef ReverseDigraph<const Digraph> RDigraph; |
| 462 | 462 |
|
| 463 | 463 |
RDigraph rgraph(graph); |
| 464 | 464 |
|
| 465 | 465 |
int cutNum = 0; |
| 466 | 466 |
|
| 467 | 467 |
typedef StronglyConnectedCutArcsVisitor<RDigraph, ArcMap> RVisitor; |
| 468 | 468 |
RVisitor rvisitor(rgraph, cutMap, cutNum); |
| 469 | 469 |
|
| 470 | 470 |
DfsVisit<RDigraph, RVisitor> rdfs(rgraph, rvisitor); |
| 471 | 471 |
|
| 472 | 472 |
rdfs.init(); |
| 473 | 473 |
for (RIterator it = nodes.rbegin(); it != nodes.rend(); ++it) {
|
| 474 | 474 |
if (!rdfs.reached(*it)) {
|
| 475 | 475 |
rdfs.addSource(*it); |
| 476 | 476 |
rdfs.start(); |
| 477 | 477 |
} |
| 478 | 478 |
} |
| 479 | 479 |
return cutNum; |
| 480 | 480 |
} |
| 481 | 481 |
|
| 482 | 482 |
namespace _connectivity_bits {
|
| 483 | 483 |
|
| 484 | 484 |
template <typename Digraph> |
| 485 | 485 |
class CountBiNodeConnectedComponentsVisitor : public DfsVisitor<Digraph> {
|
| 486 | 486 |
public: |
| 487 | 487 |
typedef typename Digraph::Node Node; |
| 488 | 488 |
typedef typename Digraph::Arc Arc; |
| 489 | 489 |
typedef typename Digraph::Edge Edge; |
| 490 | 490 |
|
| 491 | 491 |
CountBiNodeConnectedComponentsVisitor(const Digraph& graph, int &compNum) |
| 492 | 492 |
: _graph(graph), _compNum(compNum), |
| 493 | 493 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 494 | 494 |
|
| 495 | 495 |
void start(const Node& node) {
|
| 496 | 496 |
_predMap.set(node, INVALID); |
| 497 | 497 |
} |
| 498 | 498 |
|
| 499 | 499 |
void reach(const Node& node) {
|
| 500 | 500 |
_numMap.set(node, _num); |
| 501 | 501 |
_retMap.set(node, _num); |
| 502 | 502 |
++_num; |
| 503 | 503 |
} |
| 504 | 504 |
|
| 505 | 505 |
void discover(const Arc& edge) {
|
| 506 | 506 |
_predMap.set(_graph.target(edge), _graph.source(edge)); |
| 507 | 507 |
} |
| 508 | 508 |
|
| 509 | 509 |
void examine(const Arc& edge) {
|
| 510 | 510 |
if (_graph.source(edge) == _graph.target(edge) && |
| 511 | 511 |
_graph.direction(edge)) {
|
| 512 | 512 |
++_compNum; |
| 513 | 513 |
return; |
| 514 | 514 |
} |
| 515 | 515 |
if (_predMap[_graph.source(edge)] == _graph.target(edge)) {
|
| 516 | 516 |
return; |
| 517 | 517 |
} |
| 518 | 518 |
if (_retMap[_graph.source(edge)] > _numMap[_graph.target(edge)]) {
|
| 519 | 519 |
_retMap.set(_graph.source(edge), _numMap[_graph.target(edge)]); |
| 520 | 520 |
} |
| 521 | 521 |
} |
| 522 | 522 |
|
| 523 | 523 |
void backtrack(const Arc& edge) {
|
| 524 | 524 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 525 | 525 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 526 | 526 |
} |
| 527 | 527 |
if (_numMap[_graph.source(edge)] <= _retMap[_graph.target(edge)]) {
|
| 528 | 528 |
++_compNum; |
| 529 | 529 |
} |
| 530 | 530 |
} |
| 531 | 531 |
|
| 532 | 532 |
private: |
| 533 | 533 |
const Digraph& _graph; |
| 534 | 534 |
int& _compNum; |
| 535 | 535 |
|
| 536 | 536 |
typename Digraph::template NodeMap<int> _numMap; |
| 537 | 537 |
typename Digraph::template NodeMap<int> _retMap; |
| 538 | 538 |
typename Digraph::template NodeMap<Node> _predMap; |
| 539 | 539 |
int _num; |
| 540 | 540 |
}; |
| 541 | 541 |
|
| 542 | 542 |
template <typename Digraph, typename ArcMap> |
| 543 | 543 |
class BiNodeConnectedComponentsVisitor : public DfsVisitor<Digraph> {
|
| 544 | 544 |
public: |
| 545 | 545 |
typedef typename Digraph::Node Node; |
| 546 | 546 |
typedef typename Digraph::Arc Arc; |
| 547 | 547 |
typedef typename Digraph::Edge Edge; |
| 548 | 548 |
|
| 549 | 549 |
BiNodeConnectedComponentsVisitor(const Digraph& graph, |
| 550 | 550 |
ArcMap& compMap, int &compNum) |
| 551 | 551 |
: _graph(graph), _compMap(compMap), _compNum(compNum), |
| 552 | 552 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 553 | 553 |
|
| 554 | 554 |
void start(const Node& node) {
|
| 555 | 555 |
_predMap.set(node, INVALID); |
| 556 | 556 |
} |
| 557 | 557 |
|
| 558 | 558 |
void reach(const Node& node) {
|
| 559 | 559 |
_numMap.set(node, _num); |
| 560 | 560 |
_retMap.set(node, _num); |
| 561 | 561 |
++_num; |
| 562 | 562 |
} |
| 563 | 563 |
|
| 564 | 564 |
void discover(const Arc& edge) {
|
| 565 | 565 |
Node target = _graph.target(edge); |
| 566 | 566 |
_predMap.set(target, edge); |
| 567 | 567 |
_edgeStack.push(edge); |
| 568 | 568 |
} |
| 569 | 569 |
|
| 570 | 570 |
void examine(const Arc& edge) {
|
| 571 | 571 |
Node source = _graph.source(edge); |
| 572 | 572 |
Node target = _graph.target(edge); |
| 573 | 573 |
if (source == target && _graph.direction(edge)) {
|
| 574 | 574 |
_compMap.set(edge, _compNum); |
| 575 | 575 |
++_compNum; |
| 576 | 576 |
return; |
| 577 | 577 |
} |
| 578 | 578 |
if (_numMap[target] < _numMap[source]) {
|
| 579 | 579 |
if (_predMap[source] != _graph.oppositeArc(edge)) {
|
| 580 | 580 |
_edgeStack.push(edge); |
| 581 | 581 |
} |
| 582 | 582 |
} |
| 583 | 583 |
if (_predMap[source] != INVALID && |
| 584 | 584 |
target == _graph.source(_predMap[source])) {
|
| 585 | 585 |
return; |
| 586 | 586 |
} |
| 587 | 587 |
if (_retMap[source] > _numMap[target]) {
|
| 588 | 588 |
_retMap.set(source, _numMap[target]); |
| 589 | 589 |
} |
| 590 | 590 |
} |
| 591 | 591 |
|
| 592 | 592 |
void backtrack(const Arc& edge) {
|
| 593 | 593 |
Node source = _graph.source(edge); |
| 594 | 594 |
Node target = _graph.target(edge); |
| 595 | 595 |
if (_retMap[source] > _retMap[target]) {
|
| 596 | 596 |
_retMap.set(source, _retMap[target]); |
| 597 | 597 |
} |
| 598 | 598 |
if (_numMap[source] <= _retMap[target]) {
|
| 599 | 599 |
while (_edgeStack.top() != edge) {
|
| 600 | 600 |
_compMap.set(_edgeStack.top(), _compNum); |
| 601 | 601 |
_edgeStack.pop(); |
| 602 | 602 |
} |
| 603 | 603 |
_compMap.set(edge, _compNum); |
| 604 | 604 |
_edgeStack.pop(); |
| 605 | 605 |
++_compNum; |
| 606 | 606 |
} |
| 607 | 607 |
} |
| 608 | 608 |
|
| 609 | 609 |
private: |
| 610 | 610 |
const Digraph& _graph; |
| 611 | 611 |
ArcMap& _compMap; |
| 612 | 612 |
int& _compNum; |
| 613 | 613 |
|
| 614 | 614 |
typename Digraph::template NodeMap<int> _numMap; |
| 615 | 615 |
typename Digraph::template NodeMap<int> _retMap; |
| 616 | 616 |
typename Digraph::template NodeMap<Arc> _predMap; |
| 617 | 617 |
std::stack<Edge> _edgeStack; |
| 618 | 618 |
int _num; |
| 619 | 619 |
}; |
| 620 | 620 |
|
| 621 | 621 |
|
| 622 | 622 |
template <typename Digraph, typename NodeMap> |
| 623 | 623 |
class BiNodeConnectedCutNodesVisitor : public DfsVisitor<Digraph> {
|
| 624 | 624 |
public: |
| 625 | 625 |
typedef typename Digraph::Node Node; |
| 626 | 626 |
typedef typename Digraph::Arc Arc; |
| 627 | 627 |
typedef typename Digraph::Edge Edge; |
| 628 | 628 |
|
| 629 | 629 |
BiNodeConnectedCutNodesVisitor(const Digraph& graph, NodeMap& cutMap, |
| 630 | 630 |
int& cutNum) |
| 631 | 631 |
: _graph(graph), _cutMap(cutMap), _cutNum(cutNum), |
| 632 | 632 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 633 | 633 |
|
| 634 | 634 |
void start(const Node& node) {
|
| 635 | 635 |
_predMap.set(node, INVALID); |
| 636 | 636 |
rootCut = false; |
| 637 | 637 |
} |
| 638 | 638 |
|
| 639 | 639 |
void reach(const Node& node) {
|
| 640 | 640 |
_numMap.set(node, _num); |
| 641 | 641 |
_retMap.set(node, _num); |
| 642 | 642 |
++_num; |
| 643 | 643 |
} |
| 644 | 644 |
|
| 645 | 645 |
void discover(const Arc& edge) {
|
| 646 | 646 |
_predMap.set(_graph.target(edge), _graph.source(edge)); |
| 647 | 647 |
} |
| 648 | 648 |
|
| 649 | 649 |
void examine(const Arc& edge) {
|
| 650 | 650 |
if (_graph.source(edge) == _graph.target(edge) && |
| 651 | 651 |
_graph.direction(edge)) {
|
| 652 | 652 |
if (!_cutMap[_graph.source(edge)]) {
|
| 653 | 653 |
_cutMap.set(_graph.source(edge), true); |
| 654 | 654 |
++_cutNum; |
| 655 | 655 |
} |
| 656 | 656 |
return; |
| 657 | 657 |
} |
| 658 | 658 |
if (_predMap[_graph.source(edge)] == _graph.target(edge)) return; |
| 659 | 659 |
if (_retMap[_graph.source(edge)] > _numMap[_graph.target(edge)]) {
|
| 660 | 660 |
_retMap.set(_graph.source(edge), _numMap[_graph.target(edge)]); |
| 661 | 661 |
} |
| 662 | 662 |
} |
| 663 | 663 |
|
| 664 | 664 |
void backtrack(const Arc& edge) {
|
| 665 | 665 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 666 | 666 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 667 | 667 |
} |
| 668 | 668 |
if (_numMap[_graph.source(edge)] <= _retMap[_graph.target(edge)]) {
|
| 669 | 669 |
if (_predMap[_graph.source(edge)] != INVALID) {
|
| 670 | 670 |
if (!_cutMap[_graph.source(edge)]) {
|
| 671 | 671 |
_cutMap.set(_graph.source(edge), true); |
| 672 | 672 |
++_cutNum; |
| 673 | 673 |
} |
| 674 | 674 |
} else if (rootCut) {
|
| 675 | 675 |
if (!_cutMap[_graph.source(edge)]) {
|
| 676 | 676 |
_cutMap.set(_graph.source(edge), true); |
| 677 | 677 |
++_cutNum; |
| 678 | 678 |
} |
| 679 | 679 |
} else {
|
| 680 | 680 |
rootCut = true; |
| 681 | 681 |
} |
| 682 | 682 |
} |
| ... | ... |
@@ -844,732 +844,732 @@ |
| 844 | 844 |
|
| 845 | 845 |
CountBiEdgeConnectedComponentsVisitor(const Digraph& graph, int &compNum) |
| 846 | 846 |
: _graph(graph), _compNum(compNum), |
| 847 | 847 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 848 | 848 |
|
| 849 | 849 |
void start(const Node& node) {
|
| 850 | 850 |
_predMap.set(node, INVALID); |
| 851 | 851 |
} |
| 852 | 852 |
|
| 853 | 853 |
void reach(const Node& node) {
|
| 854 | 854 |
_numMap.set(node, _num); |
| 855 | 855 |
_retMap.set(node, _num); |
| 856 | 856 |
++_num; |
| 857 | 857 |
} |
| 858 | 858 |
|
| 859 | 859 |
void leave(const Node& node) {
|
| 860 | 860 |
if (_numMap[node] <= _retMap[node]) {
|
| 861 | 861 |
++_compNum; |
| 862 | 862 |
} |
| 863 | 863 |
} |
| 864 | 864 |
|
| 865 | 865 |
void discover(const Arc& edge) {
|
| 866 | 866 |
_predMap.set(_graph.target(edge), edge); |
| 867 | 867 |
} |
| 868 | 868 |
|
| 869 | 869 |
void examine(const Arc& edge) {
|
| 870 | 870 |
if (_predMap[_graph.source(edge)] == _graph.oppositeArc(edge)) {
|
| 871 | 871 |
return; |
| 872 | 872 |
} |
| 873 | 873 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 874 | 874 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 875 | 875 |
} |
| 876 | 876 |
} |
| 877 | 877 |
|
| 878 | 878 |
void backtrack(const Arc& edge) {
|
| 879 | 879 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 880 | 880 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 881 | 881 |
} |
| 882 | 882 |
} |
| 883 | 883 |
|
| 884 | 884 |
private: |
| 885 | 885 |
const Digraph& _graph; |
| 886 | 886 |
int& _compNum; |
| 887 | 887 |
|
| 888 | 888 |
typename Digraph::template NodeMap<int> _numMap; |
| 889 | 889 |
typename Digraph::template NodeMap<int> _retMap; |
| 890 | 890 |
typename Digraph::template NodeMap<Arc> _predMap; |
| 891 | 891 |
int _num; |
| 892 | 892 |
}; |
| 893 | 893 |
|
| 894 | 894 |
template <typename Digraph, typename NodeMap> |
| 895 | 895 |
class BiEdgeConnectedComponentsVisitor : public DfsVisitor<Digraph> {
|
| 896 | 896 |
public: |
| 897 | 897 |
typedef typename Digraph::Node Node; |
| 898 | 898 |
typedef typename Digraph::Arc Arc; |
| 899 | 899 |
typedef typename Digraph::Edge Edge; |
| 900 | 900 |
|
| 901 | 901 |
BiEdgeConnectedComponentsVisitor(const Digraph& graph, |
| 902 | 902 |
NodeMap& compMap, int &compNum) |
| 903 | 903 |
: _graph(graph), _compMap(compMap), _compNum(compNum), |
| 904 | 904 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 905 | 905 |
|
| 906 | 906 |
void start(const Node& node) {
|
| 907 | 907 |
_predMap.set(node, INVALID); |
| 908 | 908 |
} |
| 909 | 909 |
|
| 910 | 910 |
void reach(const Node& node) {
|
| 911 | 911 |
_numMap.set(node, _num); |
| 912 | 912 |
_retMap.set(node, _num); |
| 913 | 913 |
_nodeStack.push(node); |
| 914 | 914 |
++_num; |
| 915 | 915 |
} |
| 916 | 916 |
|
| 917 | 917 |
void leave(const Node& node) {
|
| 918 | 918 |
if (_numMap[node] <= _retMap[node]) {
|
| 919 | 919 |
while (_nodeStack.top() != node) {
|
| 920 | 920 |
_compMap.set(_nodeStack.top(), _compNum); |
| 921 | 921 |
_nodeStack.pop(); |
| 922 | 922 |
} |
| 923 | 923 |
_compMap.set(node, _compNum); |
| 924 | 924 |
_nodeStack.pop(); |
| 925 | 925 |
++_compNum; |
| 926 | 926 |
} |
| 927 | 927 |
} |
| 928 | 928 |
|
| 929 | 929 |
void discover(const Arc& edge) {
|
| 930 | 930 |
_predMap.set(_graph.target(edge), edge); |
| 931 | 931 |
} |
| 932 | 932 |
|
| 933 | 933 |
void examine(const Arc& edge) {
|
| 934 | 934 |
if (_predMap[_graph.source(edge)] == _graph.oppositeArc(edge)) {
|
| 935 | 935 |
return; |
| 936 | 936 |
} |
| 937 | 937 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 938 | 938 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 939 | 939 |
} |
| 940 | 940 |
} |
| 941 | 941 |
|
| 942 | 942 |
void backtrack(const Arc& edge) {
|
| 943 | 943 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 944 | 944 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 945 | 945 |
} |
| 946 | 946 |
} |
| 947 | 947 |
|
| 948 | 948 |
private: |
| 949 | 949 |
const Digraph& _graph; |
| 950 | 950 |
NodeMap& _compMap; |
| 951 | 951 |
int& _compNum; |
| 952 | 952 |
|
| 953 | 953 |
typename Digraph::template NodeMap<int> _numMap; |
| 954 | 954 |
typename Digraph::template NodeMap<int> _retMap; |
| 955 | 955 |
typename Digraph::template NodeMap<Arc> _predMap; |
| 956 | 956 |
std::stack<Node> _nodeStack; |
| 957 | 957 |
int _num; |
| 958 | 958 |
}; |
| 959 | 959 |
|
| 960 | 960 |
|
| 961 | 961 |
template <typename Digraph, typename ArcMap> |
| 962 | 962 |
class BiEdgeConnectedCutEdgesVisitor : public DfsVisitor<Digraph> {
|
| 963 | 963 |
public: |
| 964 | 964 |
typedef typename Digraph::Node Node; |
| 965 | 965 |
typedef typename Digraph::Arc Arc; |
| 966 | 966 |
typedef typename Digraph::Edge Edge; |
| 967 | 967 |
|
| 968 | 968 |
BiEdgeConnectedCutEdgesVisitor(const Digraph& graph, |
| 969 | 969 |
ArcMap& cutMap, int &cutNum) |
| 970 | 970 |
: _graph(graph), _cutMap(cutMap), _cutNum(cutNum), |
| 971 | 971 |
_numMap(graph), _retMap(graph), _predMap(graph), _num(0) {}
|
| 972 | 972 |
|
| 973 | 973 |
void start(const Node& node) {
|
| 974 | 974 |
_predMap[node] = INVALID; |
| 975 | 975 |
} |
| 976 | 976 |
|
| 977 | 977 |
void reach(const Node& node) {
|
| 978 | 978 |
_numMap.set(node, _num); |
| 979 | 979 |
_retMap.set(node, _num); |
| 980 | 980 |
++_num; |
| 981 | 981 |
} |
| 982 | 982 |
|
| 983 | 983 |
void leave(const Node& node) {
|
| 984 | 984 |
if (_numMap[node] <= _retMap[node]) {
|
| 985 | 985 |
if (_predMap[node] != INVALID) {
|
| 986 | 986 |
_cutMap.set(_predMap[node], true); |
| 987 | 987 |
++_cutNum; |
| 988 | 988 |
} |
| 989 | 989 |
} |
| 990 | 990 |
} |
| 991 | 991 |
|
| 992 | 992 |
void discover(const Arc& edge) {
|
| 993 | 993 |
_predMap.set(_graph.target(edge), edge); |
| 994 | 994 |
} |
| 995 | 995 |
|
| 996 | 996 |
void examine(const Arc& edge) {
|
| 997 | 997 |
if (_predMap[_graph.source(edge)] == _graph.oppositeArc(edge)) {
|
| 998 | 998 |
return; |
| 999 | 999 |
} |
| 1000 | 1000 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 1001 | 1001 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 1002 | 1002 |
} |
| 1003 | 1003 |
} |
| 1004 | 1004 |
|
| 1005 | 1005 |
void backtrack(const Arc& edge) {
|
| 1006 | 1006 |
if (_retMap[_graph.source(edge)] > _retMap[_graph.target(edge)]) {
|
| 1007 | 1007 |
_retMap.set(_graph.source(edge), _retMap[_graph.target(edge)]); |
| 1008 | 1008 |
} |
| 1009 | 1009 |
} |
| 1010 | 1010 |
|
| 1011 | 1011 |
private: |
| 1012 | 1012 |
const Digraph& _graph; |
| 1013 | 1013 |
ArcMap& _cutMap; |
| 1014 | 1014 |
int& _cutNum; |
| 1015 | 1015 |
|
| 1016 | 1016 |
typename Digraph::template NodeMap<int> _numMap; |
| 1017 | 1017 |
typename Digraph::template NodeMap<int> _retMap; |
| 1018 | 1018 |
typename Digraph::template NodeMap<Arc> _predMap; |
| 1019 | 1019 |
int _num; |
| 1020 | 1020 |
}; |
| 1021 | 1021 |
} |
| 1022 | 1022 |
|
| 1023 | 1023 |
template <typename Graph> |
| 1024 | 1024 |
int countBiEdgeConnectedComponents(const Graph& graph); |
| 1025 | 1025 |
|
| 1026 | 1026 |
/// \ingroup connectivity |
| 1027 | 1027 |
/// |
| 1028 | 1028 |
/// \brief Checks that the graph is bi-edge-connected. |
| 1029 | 1029 |
/// |
| 1030 | 1030 |
/// This function checks that the graph is bi-edge-connected. The undirected |
| 1031 | 1031 |
/// graph is bi-edge-connected when any two nodes are connected with two |
| 1032 | 1032 |
/// edge-disjoint paths. |
| 1033 | 1033 |
/// |
| 1034 | 1034 |
/// \param graph The undirected graph. |
| 1035 | 1035 |
/// \return The number of components. |
| 1036 | 1036 |
template <typename Graph> |
| 1037 | 1037 |
bool biEdgeConnected(const Graph& graph) {
|
| 1038 | 1038 |
return countBiEdgeConnectedComponents(graph) <= 1; |
| 1039 | 1039 |
} |
| 1040 | 1040 |
|
| 1041 | 1041 |
/// \ingroup connectivity |
| 1042 | 1042 |
/// |
| 1043 | 1043 |
/// \brief Count the bi-edge-connected components. |
| 1044 | 1044 |
/// |
| 1045 | 1045 |
/// This function count the bi-edge-connected components in an undirected |
| 1046 | 1046 |
/// graph. The bi-edge-connected components are the classes of an equivalence |
| 1047 | 1047 |
/// relation on the nodes. Two nodes are in relationship when they are |
| 1048 | 1048 |
/// connected with at least two edge-disjoint paths. |
| 1049 | 1049 |
/// |
| 1050 | 1050 |
/// \param graph The undirected graph. |
| 1051 | 1051 |
/// \return The number of components. |
| 1052 | 1052 |
template <typename Graph> |
| 1053 | 1053 |
int countBiEdgeConnectedComponents(const Graph& graph) {
|
| 1054 | 1054 |
checkConcept<concepts::Graph, Graph>(); |
| 1055 | 1055 |
typedef typename Graph::NodeIt NodeIt; |
| 1056 | 1056 |
|
| 1057 | 1057 |
using namespace _connectivity_bits; |
| 1058 | 1058 |
|
| 1059 | 1059 |
typedef CountBiEdgeConnectedComponentsVisitor<Graph> Visitor; |
| 1060 | 1060 |
|
| 1061 | 1061 |
int compNum = 0; |
| 1062 | 1062 |
Visitor visitor(graph, compNum); |
| 1063 | 1063 |
|
| 1064 | 1064 |
DfsVisit<Graph, Visitor> dfs(graph, visitor); |
| 1065 | 1065 |
dfs.init(); |
| 1066 | 1066 |
|
| 1067 | 1067 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1068 | 1068 |
if (!dfs.reached(it)) {
|
| 1069 | 1069 |
dfs.addSource(it); |
| 1070 | 1070 |
dfs.start(); |
| 1071 | 1071 |
} |
| 1072 | 1072 |
} |
| 1073 | 1073 |
return compNum; |
| 1074 | 1074 |
} |
| 1075 | 1075 |
|
| 1076 | 1076 |
/// \ingroup connectivity |
| 1077 | 1077 |
/// |
| 1078 | 1078 |
/// \brief Find the bi-edge-connected components. |
| 1079 | 1079 |
/// |
| 1080 | 1080 |
/// This function finds the bi-edge-connected components in an undirected |
| 1081 | 1081 |
/// graph. The bi-edge-connected components are the classes of an equivalence |
| 1082 | 1082 |
/// relation on the nodes. Two nodes are in relationship when they are |
| 1083 | 1083 |
/// connected at least two edge-disjoint paths. |
| 1084 | 1084 |
/// |
| 1085 | 1085 |
/// \param graph The graph. |
| 1086 | 1086 |
/// \retval compMap A writable node map. The values will be set from 0 to |
| 1087 | 1087 |
/// the number of the biconnected components minus one. Each values |
| 1088 | 1088 |
/// of the map will be set exactly once, the values of a certain component |
| 1089 | 1089 |
/// will be set continuously. |
| 1090 | 1090 |
/// \return The number of components. |
| 1091 | 1091 |
/// |
| 1092 | 1092 |
template <typename Graph, typename NodeMap> |
| 1093 | 1093 |
int biEdgeConnectedComponents(const Graph& graph, NodeMap& compMap) {
|
| 1094 | 1094 |
checkConcept<concepts::Graph, Graph>(); |
| 1095 | 1095 |
typedef typename Graph::NodeIt NodeIt; |
| 1096 | 1096 |
typedef typename Graph::Node Node; |
| 1097 | 1097 |
checkConcept<concepts::WriteMap<Node, int>, NodeMap>(); |
| 1098 | 1098 |
|
| 1099 | 1099 |
using namespace _connectivity_bits; |
| 1100 | 1100 |
|
| 1101 | 1101 |
typedef BiEdgeConnectedComponentsVisitor<Graph, NodeMap> Visitor; |
| 1102 | 1102 |
|
| 1103 | 1103 |
int compNum = 0; |
| 1104 | 1104 |
Visitor visitor(graph, compMap, compNum); |
| 1105 | 1105 |
|
| 1106 | 1106 |
DfsVisit<Graph, Visitor> dfs(graph, visitor); |
| 1107 | 1107 |
dfs.init(); |
| 1108 | 1108 |
|
| 1109 | 1109 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1110 | 1110 |
if (!dfs.reached(it)) {
|
| 1111 | 1111 |
dfs.addSource(it); |
| 1112 | 1112 |
dfs.start(); |
| 1113 | 1113 |
} |
| 1114 | 1114 |
} |
| 1115 | 1115 |
return compNum; |
| 1116 | 1116 |
} |
| 1117 | 1117 |
|
| 1118 | 1118 |
/// \ingroup connectivity |
| 1119 | 1119 |
/// |
| 1120 | 1120 |
/// \brief Find the bi-edge-connected cut edges. |
| 1121 | 1121 |
/// |
| 1122 | 1122 |
/// This function finds the bi-edge-connected components in an undirected |
| 1123 | 1123 |
/// graph. The bi-edge-connected components are the classes of an equivalence |
| 1124 | 1124 |
/// relation on the nodes. Two nodes are in relationship when they are |
| 1125 | 1125 |
/// connected with at least two edge-disjoint paths. The bi-edge-connected |
| 1126 | 1126 |
/// components are separted by edges which are the cut edges of the |
| 1127 | 1127 |
/// components. |
| 1128 | 1128 |
/// |
| 1129 | 1129 |
/// \param graph The graph. |
| 1130 | 1130 |
/// \retval cutMap A writable node map. The values will be set true when the |
| 1131 | 1131 |
/// edge is a cut edge. |
| 1132 | 1132 |
/// \return The number of cut edges. |
| 1133 | 1133 |
template <typename Graph, typename EdgeMap> |
| 1134 | 1134 |
int biEdgeConnectedCutEdges(const Graph& graph, EdgeMap& cutMap) {
|
| 1135 | 1135 |
checkConcept<concepts::Graph, Graph>(); |
| 1136 | 1136 |
typedef typename Graph::NodeIt NodeIt; |
| 1137 | 1137 |
typedef typename Graph::Edge Edge; |
| 1138 | 1138 |
checkConcept<concepts::WriteMap<Edge, bool>, EdgeMap>(); |
| 1139 | 1139 |
|
| 1140 | 1140 |
using namespace _connectivity_bits; |
| 1141 | 1141 |
|
| 1142 | 1142 |
typedef BiEdgeConnectedCutEdgesVisitor<Graph, EdgeMap> Visitor; |
| 1143 | 1143 |
|
| 1144 | 1144 |
int cutNum = 0; |
| 1145 | 1145 |
Visitor visitor(graph, cutMap, cutNum); |
| 1146 | 1146 |
|
| 1147 | 1147 |
DfsVisit<Graph, Visitor> dfs(graph, visitor); |
| 1148 | 1148 |
dfs.init(); |
| 1149 | 1149 |
|
| 1150 | 1150 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1151 | 1151 |
if (!dfs.reached(it)) {
|
| 1152 | 1152 |
dfs.addSource(it); |
| 1153 | 1153 |
dfs.start(); |
| 1154 | 1154 |
} |
| 1155 | 1155 |
} |
| 1156 | 1156 |
return cutNum; |
| 1157 | 1157 |
} |
| 1158 | 1158 |
|
| 1159 | 1159 |
|
| 1160 | 1160 |
namespace _connectivity_bits {
|
| 1161 | 1161 |
|
| 1162 | 1162 |
template <typename Digraph, typename IntNodeMap> |
| 1163 | 1163 |
class TopologicalSortVisitor : public DfsVisitor<Digraph> {
|
| 1164 | 1164 |
public: |
| 1165 | 1165 |
typedef typename Digraph::Node Node; |
| 1166 | 1166 |
typedef typename Digraph::Arc edge; |
| 1167 | 1167 |
|
| 1168 | 1168 |
TopologicalSortVisitor(IntNodeMap& order, int num) |
| 1169 | 1169 |
: _order(order), _num(num) {}
|
| 1170 | 1170 |
|
| 1171 | 1171 |
void leave(const Node& node) {
|
| 1172 | 1172 |
_order.set(node, --_num); |
| 1173 | 1173 |
} |
| 1174 | 1174 |
|
| 1175 | 1175 |
private: |
| 1176 | 1176 |
IntNodeMap& _order; |
| 1177 | 1177 |
int _num; |
| 1178 | 1178 |
}; |
| 1179 | 1179 |
|
| 1180 | 1180 |
} |
| 1181 | 1181 |
|
| 1182 | 1182 |
/// \ingroup connectivity |
| 1183 | 1183 |
/// |
| 1184 | 1184 |
/// \brief Sort the nodes of a DAG into topolgical order. |
| 1185 | 1185 |
/// |
| 1186 | 1186 |
/// Sort the nodes of a DAG into topolgical order. |
| 1187 | 1187 |
/// |
| 1188 | 1188 |
/// \param graph The graph. It must be directed and acyclic. |
| 1189 | 1189 |
/// \retval order A writable node map. The values will be set from 0 to |
| 1190 | 1190 |
/// the number of the nodes in the graph minus one. Each values of the map |
| 1191 | 1191 |
/// will be set exactly once, the values will be set descending order. |
| 1192 | 1192 |
/// |
| 1193 | 1193 |
/// \see checkedTopologicalSort |
| 1194 | 1194 |
/// \see dag |
| 1195 | 1195 |
template <typename Digraph, typename NodeMap> |
| 1196 | 1196 |
void topologicalSort(const Digraph& graph, NodeMap& order) {
|
| 1197 | 1197 |
using namespace _connectivity_bits; |
| 1198 | 1198 |
|
| 1199 | 1199 |
checkConcept<concepts::Digraph, Digraph>(); |
| 1200 | 1200 |
checkConcept<concepts::WriteMap<typename Digraph::Node, int>, NodeMap>(); |
| 1201 | 1201 |
|
| 1202 | 1202 |
typedef typename Digraph::Node Node; |
| 1203 | 1203 |
typedef typename Digraph::NodeIt NodeIt; |
| 1204 | 1204 |
typedef typename Digraph::Arc Arc; |
| 1205 | 1205 |
|
| 1206 | 1206 |
TopologicalSortVisitor<Digraph, NodeMap> |
| 1207 | 1207 |
visitor(order, countNodes(graph)); |
| 1208 | 1208 |
|
| 1209 | 1209 |
DfsVisit<Digraph, TopologicalSortVisitor<Digraph, NodeMap> > |
| 1210 | 1210 |
dfs(graph, visitor); |
| 1211 | 1211 |
|
| 1212 | 1212 |
dfs.init(); |
| 1213 | 1213 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1214 | 1214 |
if (!dfs.reached(it)) {
|
| 1215 | 1215 |
dfs.addSource(it); |
| 1216 | 1216 |
dfs.start(); |
| 1217 | 1217 |
} |
| 1218 | 1218 |
} |
| 1219 | 1219 |
} |
| 1220 | 1220 |
|
| 1221 | 1221 |
/// \ingroup connectivity |
| 1222 | 1222 |
/// |
| 1223 | 1223 |
/// \brief Sort the nodes of a DAG into topolgical order. |
| 1224 | 1224 |
/// |
| 1225 | 1225 |
/// Sort the nodes of a DAG into topolgical order. It also checks |
| 1226 | 1226 |
/// that the given graph is DAG. |
| 1227 | 1227 |
/// |
| 1228 |
/// \param |
|
| 1228 |
/// \param digraph The graph. It must be directed and acyclic. |
|
| 1229 | 1229 |
/// \retval order A readable - writable node map. The values will be set |
| 1230 | 1230 |
/// from 0 to the number of the nodes in the graph minus one. Each values |
| 1231 | 1231 |
/// of the map will be set exactly once, the values will be set descending |
| 1232 | 1232 |
/// order. |
| 1233 | 1233 |
/// \return %False when the graph is not DAG. |
| 1234 | 1234 |
/// |
| 1235 | 1235 |
/// \see topologicalSort |
| 1236 | 1236 |
/// \see dag |
| 1237 | 1237 |
template <typename Digraph, typename NodeMap> |
| 1238 | 1238 |
bool checkedTopologicalSort(const Digraph& digraph, NodeMap& order) {
|
| 1239 | 1239 |
using namespace _connectivity_bits; |
| 1240 | 1240 |
|
| 1241 | 1241 |
checkConcept<concepts::Digraph, Digraph>(); |
| 1242 | 1242 |
checkConcept<concepts::ReadWriteMap<typename Digraph::Node, int>, |
| 1243 | 1243 |
NodeMap>(); |
| 1244 | 1244 |
|
| 1245 | 1245 |
typedef typename Digraph::Node Node; |
| 1246 | 1246 |
typedef typename Digraph::NodeIt NodeIt; |
| 1247 | 1247 |
typedef typename Digraph::Arc Arc; |
| 1248 | 1248 |
|
| 1249 | 1249 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 1250 | 1250 |
order.set(it, -1); |
| 1251 | 1251 |
} |
| 1252 | 1252 |
|
| 1253 | 1253 |
TopologicalSortVisitor<Digraph, NodeMap> |
| 1254 | 1254 |
visitor(order, countNodes(digraph)); |
| 1255 | 1255 |
|
| 1256 | 1256 |
DfsVisit<Digraph, TopologicalSortVisitor<Digraph, NodeMap> > |
| 1257 | 1257 |
dfs(digraph, visitor); |
| 1258 | 1258 |
|
| 1259 | 1259 |
dfs.init(); |
| 1260 | 1260 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 1261 | 1261 |
if (!dfs.reached(it)) {
|
| 1262 | 1262 |
dfs.addSource(it); |
| 1263 | 1263 |
while (!dfs.emptyQueue()) {
|
| 1264 | 1264 |
Arc arc = dfs.nextArc(); |
| 1265 | 1265 |
Node target = digraph.target(arc); |
| 1266 | 1266 |
if (dfs.reached(target) && order[target] == -1) {
|
| 1267 | 1267 |
return false; |
| 1268 | 1268 |
} |
| 1269 | 1269 |
dfs.processNextArc(); |
| 1270 | 1270 |
} |
| 1271 | 1271 |
} |
| 1272 | 1272 |
} |
| 1273 | 1273 |
return true; |
| 1274 | 1274 |
} |
| 1275 | 1275 |
|
| 1276 | 1276 |
/// \ingroup connectivity |
| 1277 | 1277 |
/// |
| 1278 | 1278 |
/// \brief Check that the given directed graph is a DAG. |
| 1279 | 1279 |
/// |
| 1280 | 1280 |
/// Check that the given directed graph is a DAG. The DAG is |
| 1281 | 1281 |
/// an Directed Acyclic Digraph. |
| 1282 | 1282 |
/// \return %False when the graph is not DAG. |
| 1283 | 1283 |
/// \see acyclic |
| 1284 | 1284 |
template <typename Digraph> |
| 1285 | 1285 |
bool dag(const Digraph& digraph) {
|
| 1286 | 1286 |
|
| 1287 | 1287 |
checkConcept<concepts::Digraph, Digraph>(); |
| 1288 | 1288 |
|
| 1289 | 1289 |
typedef typename Digraph::Node Node; |
| 1290 | 1290 |
typedef typename Digraph::NodeIt NodeIt; |
| 1291 | 1291 |
typedef typename Digraph::Arc Arc; |
| 1292 | 1292 |
|
| 1293 | 1293 |
typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
| 1294 | 1294 |
|
| 1295 | 1295 |
typename Dfs<Digraph>::template SetProcessedMap<ProcessedMap>:: |
| 1296 | 1296 |
Create dfs(digraph); |
| 1297 | 1297 |
|
| 1298 | 1298 |
ProcessedMap processed(digraph); |
| 1299 | 1299 |
dfs.processedMap(processed); |
| 1300 | 1300 |
|
| 1301 | 1301 |
dfs.init(); |
| 1302 | 1302 |
for (NodeIt it(digraph); it != INVALID; ++it) {
|
| 1303 | 1303 |
if (!dfs.reached(it)) {
|
| 1304 | 1304 |
dfs.addSource(it); |
| 1305 | 1305 |
while (!dfs.emptyQueue()) {
|
| 1306 | 1306 |
Arc edge = dfs.nextArc(); |
| 1307 | 1307 |
Node target = digraph.target(edge); |
| 1308 | 1308 |
if (dfs.reached(target) && !processed[target]) {
|
| 1309 | 1309 |
return false; |
| 1310 | 1310 |
} |
| 1311 | 1311 |
dfs.processNextArc(); |
| 1312 | 1312 |
} |
| 1313 | 1313 |
} |
| 1314 | 1314 |
} |
| 1315 | 1315 |
return true; |
| 1316 | 1316 |
} |
| 1317 | 1317 |
|
| 1318 | 1318 |
/// \ingroup connectivity |
| 1319 | 1319 |
/// |
| 1320 | 1320 |
/// \brief Check that the given undirected graph is acyclic. |
| 1321 | 1321 |
/// |
| 1322 | 1322 |
/// Check that the given undirected graph acyclic. |
| 1323 | 1323 |
/// \param graph The undirected graph. |
| 1324 | 1324 |
/// \return %True when there is no circle in the graph. |
| 1325 | 1325 |
/// \see dag |
| 1326 | 1326 |
template <typename Graph> |
| 1327 | 1327 |
bool acyclic(const Graph& graph) {
|
| 1328 | 1328 |
checkConcept<concepts::Graph, Graph>(); |
| 1329 | 1329 |
typedef typename Graph::Node Node; |
| 1330 | 1330 |
typedef typename Graph::NodeIt NodeIt; |
| 1331 | 1331 |
typedef typename Graph::Arc Arc; |
| 1332 | 1332 |
Dfs<Graph> dfs(graph); |
| 1333 | 1333 |
dfs.init(); |
| 1334 | 1334 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1335 | 1335 |
if (!dfs.reached(it)) {
|
| 1336 | 1336 |
dfs.addSource(it); |
| 1337 | 1337 |
while (!dfs.emptyQueue()) {
|
| 1338 | 1338 |
Arc edge = dfs.nextArc(); |
| 1339 | 1339 |
Node source = graph.source(edge); |
| 1340 | 1340 |
Node target = graph.target(edge); |
| 1341 | 1341 |
if (dfs.reached(target) && |
| 1342 | 1342 |
dfs.predArc(source) != graph.oppositeArc(edge)) {
|
| 1343 | 1343 |
return false; |
| 1344 | 1344 |
} |
| 1345 | 1345 |
dfs.processNextArc(); |
| 1346 | 1346 |
} |
| 1347 | 1347 |
} |
| 1348 | 1348 |
} |
| 1349 | 1349 |
return true; |
| 1350 | 1350 |
} |
| 1351 | 1351 |
|
| 1352 | 1352 |
/// \ingroup connectivity |
| 1353 | 1353 |
/// |
| 1354 | 1354 |
/// \brief Check that the given undirected graph is tree. |
| 1355 | 1355 |
/// |
| 1356 | 1356 |
/// Check that the given undirected graph is tree. |
| 1357 | 1357 |
/// \param graph The undirected graph. |
| 1358 | 1358 |
/// \return %True when the graph is acyclic and connected. |
| 1359 | 1359 |
template <typename Graph> |
| 1360 | 1360 |
bool tree(const Graph& graph) {
|
| 1361 | 1361 |
checkConcept<concepts::Graph, Graph>(); |
| 1362 | 1362 |
typedef typename Graph::Node Node; |
| 1363 | 1363 |
typedef typename Graph::NodeIt NodeIt; |
| 1364 | 1364 |
typedef typename Graph::Arc Arc; |
| 1365 | 1365 |
Dfs<Graph> dfs(graph); |
| 1366 | 1366 |
dfs.init(); |
| 1367 | 1367 |
dfs.addSource(NodeIt(graph)); |
| 1368 | 1368 |
while (!dfs.emptyQueue()) {
|
| 1369 | 1369 |
Arc edge = dfs.nextArc(); |
| 1370 | 1370 |
Node source = graph.source(edge); |
| 1371 | 1371 |
Node target = graph.target(edge); |
| 1372 | 1372 |
if (dfs.reached(target) && |
| 1373 | 1373 |
dfs.predArc(source) != graph.oppositeArc(edge)) {
|
| 1374 | 1374 |
return false; |
| 1375 | 1375 |
} |
| 1376 | 1376 |
dfs.processNextArc(); |
| 1377 | 1377 |
} |
| 1378 | 1378 |
for (NodeIt it(graph); it != INVALID; ++it) {
|
| 1379 | 1379 |
if (!dfs.reached(it)) {
|
| 1380 | 1380 |
return false; |
| 1381 | 1381 |
} |
| 1382 | 1382 |
} |
| 1383 | 1383 |
return true; |
| 1384 | 1384 |
} |
| 1385 | 1385 |
|
| 1386 | 1386 |
namespace _connectivity_bits {
|
| 1387 | 1387 |
|
| 1388 | 1388 |
template <typename Digraph> |
| 1389 | 1389 |
class BipartiteVisitor : public BfsVisitor<Digraph> {
|
| 1390 | 1390 |
public: |
| 1391 | 1391 |
typedef typename Digraph::Arc Arc; |
| 1392 | 1392 |
typedef typename Digraph::Node Node; |
| 1393 | 1393 |
|
| 1394 | 1394 |
BipartiteVisitor(const Digraph& graph, bool& bipartite) |
| 1395 | 1395 |
: _graph(graph), _part(graph), _bipartite(bipartite) {}
|
| 1396 | 1396 |
|
| 1397 | 1397 |
void start(const Node& node) {
|
| 1398 | 1398 |
_part[node] = true; |
| 1399 | 1399 |
} |
| 1400 | 1400 |
void discover(const Arc& edge) {
|
| 1401 | 1401 |
_part.set(_graph.target(edge), !_part[_graph.source(edge)]); |
| 1402 | 1402 |
} |
| 1403 | 1403 |
void examine(const Arc& edge) {
|
| 1404 | 1404 |
_bipartite = _bipartite && |
| 1405 | 1405 |
_part[_graph.target(edge)] != _part[_graph.source(edge)]; |
| 1406 | 1406 |
} |
| 1407 | 1407 |
|
| 1408 | 1408 |
private: |
| 1409 | 1409 |
|
| 1410 | 1410 |
const Digraph& _graph; |
| 1411 | 1411 |
typename Digraph::template NodeMap<bool> _part; |
| 1412 | 1412 |
bool& _bipartite; |
| 1413 | 1413 |
}; |
| 1414 | 1414 |
|
| 1415 | 1415 |
template <typename Digraph, typename PartMap> |
| 1416 | 1416 |
class BipartitePartitionsVisitor : public BfsVisitor<Digraph> {
|
| 1417 | 1417 |
public: |
| 1418 | 1418 |
typedef typename Digraph::Arc Arc; |
| 1419 | 1419 |
typedef typename Digraph::Node Node; |
| 1420 | 1420 |
|
| 1421 | 1421 |
BipartitePartitionsVisitor(const Digraph& graph, |
| 1422 | 1422 |
PartMap& part, bool& bipartite) |
| 1423 | 1423 |
: _graph(graph), _part(part), _bipartite(bipartite) {}
|
| 1424 | 1424 |
|
| 1425 | 1425 |
void start(const Node& node) {
|
| 1426 | 1426 |
_part.set(node, true); |
| 1427 | 1427 |
} |
| 1428 | 1428 |
void discover(const Arc& edge) {
|
| 1429 | 1429 |
_part.set(_graph.target(edge), !_part[_graph.source(edge)]); |
| 1430 | 1430 |
} |
| 1431 | 1431 |
void examine(const Arc& edge) {
|
| 1432 | 1432 |
_bipartite = _bipartite && |
| 1433 | 1433 |
_part[_graph.target(edge)] != _part[_graph.source(edge)]; |
| 1434 | 1434 |
} |
| 1435 | 1435 |
|
| 1436 | 1436 |
private: |
| 1437 | 1437 |
|
| 1438 | 1438 |
const Digraph& _graph; |
| 1439 | 1439 |
PartMap& _part; |
| 1440 | 1440 |
bool& _bipartite; |
| 1441 | 1441 |
}; |
| 1442 | 1442 |
} |
| 1443 | 1443 |
|
| 1444 | 1444 |
/// \ingroup connectivity |
| 1445 | 1445 |
/// |
| 1446 | 1446 |
/// \brief Check if the given undirected graph is bipartite or not |
| 1447 | 1447 |
/// |
| 1448 | 1448 |
/// The function checks if the given undirected \c graph graph is bipartite |
| 1449 | 1449 |
/// or not. The \ref Bfs algorithm is used to calculate the result. |
| 1450 | 1450 |
/// \param graph The undirected graph. |
| 1451 | 1451 |
/// \return %True if \c graph is bipartite, %false otherwise. |
| 1452 | 1452 |
/// \sa bipartitePartitions |
| 1453 | 1453 |
template<typename Graph> |
| 1454 | 1454 |
inline bool bipartite(const Graph &graph){
|
| 1455 | 1455 |
using namespace _connectivity_bits; |
| 1456 | 1456 |
|
| 1457 | 1457 |
checkConcept<concepts::Graph, Graph>(); |
| 1458 | 1458 |
|
| 1459 | 1459 |
typedef typename Graph::NodeIt NodeIt; |
| 1460 | 1460 |
typedef typename Graph::ArcIt ArcIt; |
| 1461 | 1461 |
|
| 1462 | 1462 |
bool bipartite = true; |
| 1463 | 1463 |
|
| 1464 | 1464 |
BipartiteVisitor<Graph> |
| 1465 | 1465 |
visitor(graph, bipartite); |
| 1466 | 1466 |
BfsVisit<Graph, BipartiteVisitor<Graph> > |
| 1467 | 1467 |
bfs(graph, visitor); |
| 1468 | 1468 |
bfs.init(); |
| 1469 | 1469 |
for(NodeIt it(graph); it != INVALID; ++it) {
|
| 1470 | 1470 |
if(!bfs.reached(it)){
|
| 1471 | 1471 |
bfs.addSource(it); |
| 1472 | 1472 |
while (!bfs.emptyQueue()) {
|
| 1473 | 1473 |
bfs.processNextNode(); |
| 1474 | 1474 |
if (!bipartite) return false; |
| 1475 | 1475 |
} |
| 1476 | 1476 |
} |
| 1477 | 1477 |
} |
| 1478 | 1478 |
return true; |
| 1479 | 1479 |
} |
| 1480 | 1480 |
|
| 1481 | 1481 |
/// \ingroup connectivity |
| 1482 | 1482 |
/// |
| 1483 | 1483 |
/// \brief Check if the given undirected graph is bipartite or not |
| 1484 | 1484 |
/// |
| 1485 | 1485 |
/// The function checks if the given undirected graph is bipartite |
| 1486 | 1486 |
/// or not. The \ref Bfs algorithm is used to calculate the result. |
| 1487 | 1487 |
/// During the execution, the \c partMap will be set as the two |
| 1488 | 1488 |
/// partitions of the graph. |
| 1489 | 1489 |
/// \param graph The undirected graph. |
| 1490 | 1490 |
/// \retval partMap A writable bool map of nodes. It will be set as the |
| 1491 | 1491 |
/// two partitions of the graph. |
| 1492 | 1492 |
/// \return %True if \c graph is bipartite, %false otherwise. |
| 1493 | 1493 |
template<typename Graph, typename NodeMap> |
| 1494 | 1494 |
inline bool bipartitePartitions(const Graph &graph, NodeMap &partMap){
|
| 1495 | 1495 |
using namespace _connectivity_bits; |
| 1496 | 1496 |
|
| 1497 | 1497 |
checkConcept<concepts::Graph, Graph>(); |
| 1498 | 1498 |
|
| 1499 | 1499 |
typedef typename Graph::Node Node; |
| 1500 | 1500 |
typedef typename Graph::NodeIt NodeIt; |
| 1501 | 1501 |
typedef typename Graph::ArcIt ArcIt; |
| 1502 | 1502 |
|
| 1503 | 1503 |
bool bipartite = true; |
| 1504 | 1504 |
|
| 1505 | 1505 |
BipartitePartitionsVisitor<Graph, NodeMap> |
| 1506 | 1506 |
visitor(graph, partMap, bipartite); |
| 1507 | 1507 |
BfsVisit<Graph, BipartitePartitionsVisitor<Graph, NodeMap> > |
| 1508 | 1508 |
bfs(graph, visitor); |
| 1509 | 1509 |
bfs.init(); |
| 1510 | 1510 |
for(NodeIt it(graph); it != INVALID; ++it) {
|
| 1511 | 1511 |
if(!bfs.reached(it)){
|
| 1512 | 1512 |
bfs.addSource(it); |
| 1513 | 1513 |
while (!bfs.emptyQueue()) {
|
| 1514 | 1514 |
bfs.processNextNode(); |
| 1515 | 1515 |
if (!bipartite) return false; |
| 1516 | 1516 |
} |
| 1517 | 1517 |
} |
| 1518 | 1518 |
} |
| 1519 | 1519 |
return true; |
| 1520 | 1520 |
} |
| 1521 | 1521 |
|
| 1522 | 1522 |
/// \brief Returns true when there are not loop edges in the graph. |
| 1523 | 1523 |
/// |
| 1524 | 1524 |
/// Returns true when there are not loop edges in the graph. |
| 1525 | 1525 |
template <typename Digraph> |
| 1526 | 1526 |
bool loopFree(const Digraph& digraph) {
|
| 1527 | 1527 |
for (typename Digraph::ArcIt it(digraph); it != INVALID; ++it) {
|
| 1528 | 1528 |
if (digraph.source(it) == digraph.target(it)) return false; |
| 1529 | 1529 |
} |
| 1530 | 1530 |
return true; |
| 1531 | 1531 |
} |
| 1532 | 1532 |
|
| 1533 | 1533 |
/// \brief Returns true when there are not parallel edges in the graph. |
| 1534 | 1534 |
/// |
| 1535 | 1535 |
/// Returns true when there are not parallel edges in the graph. |
| 1536 | 1536 |
template <typename Digraph> |
| 1537 | 1537 |
bool parallelFree(const Digraph& digraph) {
|
| 1538 | 1538 |
typename Digraph::template NodeMap<bool> reached(digraph, false); |
| 1539 | 1539 |
for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) {
|
| 1540 | 1540 |
for (typename Digraph::OutArcIt a(digraph, n); a != INVALID; ++a) {
|
| 1541 | 1541 |
if (reached[digraph.target(a)]) return false; |
| 1542 | 1542 |
reached.set(digraph.target(a), true); |
| 1543 | 1543 |
} |
| 1544 | 1544 |
for (typename Digraph::OutArcIt a(digraph, n); a != INVALID; ++a) {
|
| 1545 | 1545 |
reached.set(digraph.target(a), false); |
| 1546 | 1546 |
} |
| 1547 | 1547 |
} |
| 1548 | 1548 |
return true; |
| 1549 | 1549 |
} |
| 1550 | 1550 |
|
| 1551 | 1551 |
/// \brief Returns true when there are not loop edges and parallel |
| 1552 | 1552 |
/// edges in the graph. |
| 1553 | 1553 |
/// |
| 1554 | 1554 |
/// Returns true when there are not loop edges and parallel edges in |
| 1555 | 1555 |
/// the graph. |
| 1556 | 1556 |
template <typename Digraph> |
| 1557 | 1557 |
bool simpleDigraph(const Digraph& digraph) {
|
| 1558 | 1558 |
typename Digraph::template NodeMap<bool> reached(digraph, false); |
| 1559 | 1559 |
for (typename Digraph::NodeIt n(digraph); n != INVALID; ++n) {
|
| 1560 | 1560 |
reached.set(n, true); |
| 1561 | 1561 |
for (typename Digraph::OutArcIt a(digraph, n); a != INVALID; ++a) {
|
| 1562 | 1562 |
if (reached[digraph.target(a)]) return false; |
| 1563 | 1563 |
reached.set(digraph.target(a), true); |
| 1564 | 1564 |
} |
| 1565 | 1565 |
for (typename Digraph::OutArcIt a(digraph, n); a != INVALID; ++a) {
|
| 1566 | 1566 |
reached.set(digraph.target(a), false); |
| 1567 | 1567 |
} |
| 1568 | 1568 |
reached.set(n, false); |
| 1569 | 1569 |
} |
| 1570 | 1570 |
return true; |
| 1571 | 1571 |
} |
| 1572 | 1572 |
|
| 1573 | 1573 |
} //namespace lemon |
| 1574 | 1574 |
|
| 1575 | 1575 |
#endif //LEMON_CONNECTIVITY_H |
| ... | ... |
@@ -35,769 +35,769 @@ |
| 35 | 35 |
|
| 36 | 36 |
namespace lemon {
|
| 37 | 37 |
|
| 38 | 38 |
/// \ingroup matching |
| 39 | 39 |
/// |
| 40 | 40 |
/// \brief Edmonds' alternating forest maximum matching algorithm. |
| 41 | 41 |
/// |
| 42 | 42 |
/// This class implements Edmonds' alternating forest matching |
| 43 | 43 |
/// algorithm. The algorithm can be started from an arbitrary initial |
| 44 | 44 |
/// matching (the default is the empty one) |
| 45 | 45 |
/// |
| 46 | 46 |
/// The dual solution of the problem is a map of the nodes to |
| 47 | 47 |
/// MaxMatching::Status, having values \c EVEN/D, \c ODD/A and \c |
| 48 | 48 |
/// MATCHED/C showing the Gallai-Edmonds decomposition of the |
| 49 | 49 |
/// graph. The nodes in \c EVEN/D induce a graph with |
| 50 | 50 |
/// factor-critical components, the nodes in \c ODD/A form the |
| 51 | 51 |
/// barrier, and the nodes in \c MATCHED/C induce a graph having a |
| 52 | 52 |
/// perfect matching. The number of the factor-critical components |
| 53 | 53 |
/// minus the number of barrier nodes is a lower bound on the |
| 54 | 54 |
/// unmatched nodes, and the matching is optimal if and only if this bound is |
| 55 | 55 |
/// tight. This decomposition can be attained by calling \c |
| 56 | 56 |
/// decomposition() after running the algorithm. |
| 57 | 57 |
/// |
| 58 | 58 |
/// \param _Graph The graph type the algorithm runs on. |
| 59 | 59 |
template <typename _Graph> |
| 60 | 60 |
class MaxMatching {
|
| 61 | 61 |
public: |
| 62 | 62 |
|
| 63 | 63 |
typedef _Graph Graph; |
| 64 | 64 |
typedef typename Graph::template NodeMap<typename Graph::Arc> |
| 65 | 65 |
MatchingMap; |
| 66 | 66 |
|
| 67 | 67 |
///\brief Indicates the Gallai-Edmonds decomposition of the graph. |
| 68 | 68 |
/// |
| 69 | 69 |
///Indicates the Gallai-Edmonds decomposition of the graph. The |
| 70 | 70 |
///nodes with Status \c EVEN/D induce a graph with factor-critical |
| 71 | 71 |
///components, the nodes in \c ODD/A form the canonical barrier, |
| 72 | 72 |
///and the nodes in \c MATCHED/C induce a graph having a perfect |
| 73 | 73 |
///matching. |
| 74 | 74 |
enum Status {
|
| 75 | 75 |
EVEN = 1, D = 1, MATCHED = 0, C = 0, ODD = -1, A = -1, UNMATCHED = -2 |
| 76 | 76 |
}; |
| 77 | 77 |
|
| 78 | 78 |
typedef typename Graph::template NodeMap<Status> StatusMap; |
| 79 | 79 |
|
| 80 | 80 |
private: |
| 81 | 81 |
|
| 82 | 82 |
TEMPLATE_GRAPH_TYPEDEFS(Graph); |
| 83 | 83 |
|
| 84 | 84 |
typedef UnionFindEnum<IntNodeMap> BlossomSet; |
| 85 | 85 |
typedef ExtendFindEnum<IntNodeMap> TreeSet; |
| 86 | 86 |
typedef RangeMap<Node> NodeIntMap; |
| 87 | 87 |
typedef MatchingMap EarMap; |
| 88 | 88 |
typedef std::vector<Node> NodeQueue; |
| 89 | 89 |
|
| 90 | 90 |
const Graph& _graph; |
| 91 | 91 |
MatchingMap* _matching; |
| 92 | 92 |
StatusMap* _status; |
| 93 | 93 |
|
| 94 | 94 |
EarMap* _ear; |
| 95 | 95 |
|
| 96 | 96 |
IntNodeMap* _blossom_set_index; |
| 97 | 97 |
BlossomSet* _blossom_set; |
| 98 | 98 |
NodeIntMap* _blossom_rep; |
| 99 | 99 |
|
| 100 | 100 |
IntNodeMap* _tree_set_index; |
| 101 | 101 |
TreeSet* _tree_set; |
| 102 | 102 |
|
| 103 | 103 |
NodeQueue _node_queue; |
| 104 | 104 |
int _process, _postpone, _last; |
| 105 | 105 |
|
| 106 | 106 |
int _node_num; |
| 107 | 107 |
|
| 108 | 108 |
private: |
| 109 | 109 |
|
| 110 | 110 |
void createStructures() {
|
| 111 | 111 |
_node_num = countNodes(_graph); |
| 112 | 112 |
if (!_matching) {
|
| 113 | 113 |
_matching = new MatchingMap(_graph); |
| 114 | 114 |
} |
| 115 | 115 |
if (!_status) {
|
| 116 | 116 |
_status = new StatusMap(_graph); |
| 117 | 117 |
} |
| 118 | 118 |
if (!_ear) {
|
| 119 | 119 |
_ear = new EarMap(_graph); |
| 120 | 120 |
} |
| 121 | 121 |
if (!_blossom_set) {
|
| 122 | 122 |
_blossom_set_index = new IntNodeMap(_graph); |
| 123 | 123 |
_blossom_set = new BlossomSet(*_blossom_set_index); |
| 124 | 124 |
} |
| 125 | 125 |
if (!_blossom_rep) {
|
| 126 | 126 |
_blossom_rep = new NodeIntMap(_node_num); |
| 127 | 127 |
} |
| 128 | 128 |
if (!_tree_set) {
|
| 129 | 129 |
_tree_set_index = new IntNodeMap(_graph); |
| 130 | 130 |
_tree_set = new TreeSet(*_tree_set_index); |
| 131 | 131 |
} |
| 132 | 132 |
_node_queue.resize(_node_num); |
| 133 | 133 |
} |
| 134 | 134 |
|
| 135 | 135 |
void destroyStructures() {
|
| 136 | 136 |
if (_matching) {
|
| 137 | 137 |
delete _matching; |
| 138 | 138 |
} |
| 139 | 139 |
if (_status) {
|
| 140 | 140 |
delete _status; |
| 141 | 141 |
} |
| 142 | 142 |
if (_ear) {
|
| 143 | 143 |
delete _ear; |
| 144 | 144 |
} |
| 145 | 145 |
if (_blossom_set) {
|
| 146 | 146 |
delete _blossom_set; |
| 147 | 147 |
delete _blossom_set_index; |
| 148 | 148 |
} |
| 149 | 149 |
if (_blossom_rep) {
|
| 150 | 150 |
delete _blossom_rep; |
| 151 | 151 |
} |
| 152 | 152 |
if (_tree_set) {
|
| 153 | 153 |
delete _tree_set_index; |
| 154 | 154 |
delete _tree_set; |
| 155 | 155 |
} |
| 156 | 156 |
} |
| 157 | 157 |
|
| 158 | 158 |
void processDense(const Node& n) {
|
| 159 | 159 |
_process = _postpone = _last = 0; |
| 160 | 160 |
_node_queue[_last++] = n; |
| 161 | 161 |
|
| 162 | 162 |
while (_process != _last) {
|
| 163 | 163 |
Node u = _node_queue[_process++]; |
| 164 | 164 |
for (OutArcIt a(_graph, u); a != INVALID; ++a) {
|
| 165 | 165 |
Node v = _graph.target(a); |
| 166 | 166 |
if ((*_status)[v] == MATCHED) {
|
| 167 | 167 |
extendOnArc(a); |
| 168 | 168 |
} else if ((*_status)[v] == UNMATCHED) {
|
| 169 | 169 |
augmentOnArc(a); |
| 170 | 170 |
return; |
| 171 | 171 |
} |
| 172 | 172 |
} |
| 173 | 173 |
} |
| 174 | 174 |
|
| 175 | 175 |
while (_postpone != _last) {
|
| 176 | 176 |
Node u = _node_queue[_postpone++]; |
| 177 | 177 |
|
| 178 | 178 |
for (OutArcIt a(_graph, u); a != INVALID ; ++a) {
|
| 179 | 179 |
Node v = _graph.target(a); |
| 180 | 180 |
|
| 181 | 181 |
if ((*_status)[v] == EVEN) {
|
| 182 | 182 |
if (_blossom_set->find(u) != _blossom_set->find(v)) {
|
| 183 | 183 |
shrinkOnEdge(a); |
| 184 | 184 |
} |
| 185 | 185 |
} |
| 186 | 186 |
|
| 187 | 187 |
while (_process != _last) {
|
| 188 | 188 |
Node w = _node_queue[_process++]; |
| 189 | 189 |
for (OutArcIt b(_graph, w); b != INVALID; ++b) {
|
| 190 | 190 |
Node x = _graph.target(b); |
| 191 | 191 |
if ((*_status)[x] == MATCHED) {
|
| 192 | 192 |
extendOnArc(b); |
| 193 | 193 |
} else if ((*_status)[x] == UNMATCHED) {
|
| 194 | 194 |
augmentOnArc(b); |
| 195 | 195 |
return; |
| 196 | 196 |
} |
| 197 | 197 |
} |
| 198 | 198 |
} |
| 199 | 199 |
} |
| 200 | 200 |
} |
| 201 | 201 |
} |
| 202 | 202 |
|
| 203 | 203 |
void processSparse(const Node& n) {
|
| 204 | 204 |
_process = _last = 0; |
| 205 | 205 |
_node_queue[_last++] = n; |
| 206 | 206 |
while (_process != _last) {
|
| 207 | 207 |
Node u = _node_queue[_process++]; |
| 208 | 208 |
for (OutArcIt a(_graph, u); a != INVALID; ++a) {
|
| 209 | 209 |
Node v = _graph.target(a); |
| 210 | 210 |
|
| 211 | 211 |
if ((*_status)[v] == EVEN) {
|
| 212 | 212 |
if (_blossom_set->find(u) != _blossom_set->find(v)) {
|
| 213 | 213 |
shrinkOnEdge(a); |
| 214 | 214 |
} |
| 215 | 215 |
} else if ((*_status)[v] == MATCHED) {
|
| 216 | 216 |
extendOnArc(a); |
| 217 | 217 |
} else if ((*_status)[v] == UNMATCHED) {
|
| 218 | 218 |
augmentOnArc(a); |
| 219 | 219 |
return; |
| 220 | 220 |
} |
| 221 | 221 |
} |
| 222 | 222 |
} |
| 223 | 223 |
} |
| 224 | 224 |
|
| 225 | 225 |
void shrinkOnEdge(const Edge& e) {
|
| 226 | 226 |
Node nca = INVALID; |
| 227 | 227 |
|
| 228 | 228 |
{
|
| 229 | 229 |
std::set<Node> left_set, right_set; |
| 230 | 230 |
|
| 231 | 231 |
Node left = (*_blossom_rep)[_blossom_set->find(_graph.u(e))]; |
| 232 | 232 |
left_set.insert(left); |
| 233 | 233 |
|
| 234 | 234 |
Node right = (*_blossom_rep)[_blossom_set->find(_graph.v(e))]; |
| 235 | 235 |
right_set.insert(right); |
| 236 | 236 |
|
| 237 | 237 |
while (true) {
|
| 238 | 238 |
if ((*_matching)[left] == INVALID) break; |
| 239 | 239 |
left = _graph.target((*_matching)[left]); |
| 240 | 240 |
left = (*_blossom_rep)[_blossom_set-> |
| 241 | 241 |
find(_graph.target((*_ear)[left]))]; |
| 242 | 242 |
if (right_set.find(left) != right_set.end()) {
|
| 243 | 243 |
nca = left; |
| 244 | 244 |
break; |
| 245 | 245 |
} |
| 246 | 246 |
left_set.insert(left); |
| 247 | 247 |
|
| 248 | 248 |
if ((*_matching)[right] == INVALID) break; |
| 249 | 249 |
right = _graph.target((*_matching)[right]); |
| 250 | 250 |
right = (*_blossom_rep)[_blossom_set-> |
| 251 | 251 |
find(_graph.target((*_ear)[right]))]; |
| 252 | 252 |
if (left_set.find(right) != left_set.end()) {
|
| 253 | 253 |
nca = right; |
| 254 | 254 |
break; |
| 255 | 255 |
} |
| 256 | 256 |
right_set.insert(right); |
| 257 | 257 |
} |
| 258 | 258 |
|
| 259 | 259 |
if (nca == INVALID) {
|
| 260 | 260 |
if ((*_matching)[left] == INVALID) {
|
| 261 | 261 |
nca = right; |
| 262 | 262 |
while (left_set.find(nca) == left_set.end()) {
|
| 263 | 263 |
nca = _graph.target((*_matching)[nca]); |
| 264 | 264 |
nca =(*_blossom_rep)[_blossom_set-> |
| 265 | 265 |
find(_graph.target((*_ear)[nca]))]; |
| 266 | 266 |
} |
| 267 | 267 |
} else {
|
| 268 | 268 |
nca = left; |
| 269 | 269 |
while (right_set.find(nca) == right_set.end()) {
|
| 270 | 270 |
nca = _graph.target((*_matching)[nca]); |
| 271 | 271 |
nca = (*_blossom_rep)[_blossom_set-> |
| 272 | 272 |
find(_graph.target((*_ear)[nca]))]; |
| 273 | 273 |
} |
| 274 | 274 |
} |
| 275 | 275 |
} |
| 276 | 276 |
} |
| 277 | 277 |
|
| 278 | 278 |
{
|
| 279 | 279 |
|
| 280 | 280 |
Node node = _graph.u(e); |
| 281 | 281 |
Arc arc = _graph.direct(e, true); |
| 282 | 282 |
Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
| 283 | 283 |
|
| 284 | 284 |
while (base != nca) {
|
| 285 | 285 |
_ear->set(node, arc); |
| 286 | 286 |
|
| 287 | 287 |
Node n = node; |
| 288 | 288 |
while (n != base) {
|
| 289 | 289 |
n = _graph.target((*_matching)[n]); |
| 290 | 290 |
Arc a = (*_ear)[n]; |
| 291 | 291 |
n = _graph.target(a); |
| 292 | 292 |
_ear->set(n, _graph.oppositeArc(a)); |
| 293 | 293 |
} |
| 294 | 294 |
node = _graph.target((*_matching)[base]); |
| 295 | 295 |
_tree_set->erase(base); |
| 296 | 296 |
_tree_set->erase(node); |
| 297 | 297 |
_blossom_set->insert(node, _blossom_set->find(base)); |
| 298 | 298 |
_status->set(node, EVEN); |
| 299 | 299 |
_node_queue[_last++] = node; |
| 300 | 300 |
arc = _graph.oppositeArc((*_ear)[node]); |
| 301 | 301 |
node = _graph.target((*_ear)[node]); |
| 302 | 302 |
base = (*_blossom_rep)[_blossom_set->find(node)]; |
| 303 | 303 |
_blossom_set->join(_graph.target(arc), base); |
| 304 | 304 |
} |
| 305 | 305 |
} |
| 306 | 306 |
|
| 307 | 307 |
_blossom_rep->set(_blossom_set->find(nca), nca); |
| 308 | 308 |
|
| 309 | 309 |
{
|
| 310 | 310 |
|
| 311 | 311 |
Node node = _graph.v(e); |
| 312 | 312 |
Arc arc = _graph.direct(e, false); |
| 313 | 313 |
Node base = (*_blossom_rep)[_blossom_set->find(node)]; |
| 314 | 314 |
|
| 315 | 315 |
while (base != nca) {
|
| 316 | 316 |
_ear->set(node, arc); |
| 317 | 317 |
|
| 318 | 318 |
Node n = node; |
| 319 | 319 |
while (n != base) {
|
| 320 | 320 |
n = _graph.target((*_matching)[n]); |
| 321 | 321 |
Arc a = (*_ear)[n]; |
| 322 | 322 |
n = _graph.target(a); |
| 323 | 323 |
_ear->set(n, _graph.oppositeArc(a)); |
| 324 | 324 |
} |
| 325 | 325 |
node = _graph.target((*_matching)[base]); |
| 326 | 326 |
_tree_set->erase(base); |
| 327 | 327 |
_tree_set->erase(node); |
| 328 | 328 |
_blossom_set->insert(node, _blossom_set->find(base)); |
| 329 | 329 |
_status->set(node, EVEN); |
| 330 | 330 |
_node_queue[_last++] = node; |
| 331 | 331 |
arc = _graph.oppositeArc((*_ear)[node]); |
| 332 | 332 |
node = _graph.target((*_ear)[node]); |
| 333 | 333 |
base = (*_blossom_rep)[_blossom_set->find(node)]; |
| 334 | 334 |
_blossom_set->join(_graph.target(arc), base); |
| 335 | 335 |
} |
| 336 | 336 |
} |
| 337 | 337 |
|
| 338 | 338 |
_blossom_rep->set(_blossom_set->find(nca), nca); |
| 339 | 339 |
} |
| 340 | 340 |
|
| 341 | 341 |
|
| 342 | 342 |
|
| 343 | 343 |
void extendOnArc(const Arc& a) {
|
| 344 | 344 |
Node base = _graph.source(a); |
| 345 | 345 |
Node odd = _graph.target(a); |
| 346 | 346 |
|
| 347 | 347 |
_ear->set(odd, _graph.oppositeArc(a)); |
| 348 | 348 |
Node even = _graph.target((*_matching)[odd]); |
| 349 | 349 |
_blossom_rep->set(_blossom_set->insert(even), even); |
| 350 | 350 |
_status->set(odd, ODD); |
| 351 | 351 |
_status->set(even, EVEN); |
| 352 | 352 |
int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(base)]); |
| 353 | 353 |
_tree_set->insert(odd, tree); |
| 354 | 354 |
_tree_set->insert(even, tree); |
| 355 | 355 |
_node_queue[_last++] = even; |
| 356 | 356 |
|
| 357 | 357 |
} |
| 358 | 358 |
|
| 359 | 359 |
void augmentOnArc(const Arc& a) {
|
| 360 | 360 |
Node even = _graph.source(a); |
| 361 | 361 |
Node odd = _graph.target(a); |
| 362 | 362 |
|
| 363 | 363 |
int tree = _tree_set->find((*_blossom_rep)[_blossom_set->find(even)]); |
| 364 | 364 |
|
| 365 | 365 |
_matching->set(odd, _graph.oppositeArc(a)); |
| 366 | 366 |
_status->set(odd, MATCHED); |
| 367 | 367 |
|
| 368 | 368 |
Arc arc = (*_matching)[even]; |
| 369 | 369 |
_matching->set(even, a); |
| 370 | 370 |
|
| 371 | 371 |
while (arc != INVALID) {
|
| 372 | 372 |
odd = _graph.target(arc); |
| 373 | 373 |
arc = (*_ear)[odd]; |
| 374 | 374 |
even = _graph.target(arc); |
| 375 | 375 |
_matching->set(odd, arc); |
| 376 | 376 |
arc = (*_matching)[even]; |
| 377 | 377 |
_matching->set(even, _graph.oppositeArc((*_matching)[odd])); |
| 378 | 378 |
} |
| 379 | 379 |
|
| 380 | 380 |
for (typename TreeSet::ItemIt it(*_tree_set, tree); |
| 381 | 381 |
it != INVALID; ++it) {
|
| 382 | 382 |
if ((*_status)[it] == ODD) {
|
| 383 | 383 |
_status->set(it, MATCHED); |
| 384 | 384 |
} else {
|
| 385 | 385 |
int blossom = _blossom_set->find(it); |
| 386 | 386 |
for (typename BlossomSet::ItemIt jt(*_blossom_set, blossom); |
| 387 | 387 |
jt != INVALID; ++jt) {
|
| 388 | 388 |
_status->set(jt, MATCHED); |
| 389 | 389 |
} |
| 390 | 390 |
_blossom_set->eraseClass(blossom); |
| 391 | 391 |
} |
| 392 | 392 |
} |
| 393 | 393 |
_tree_set->eraseClass(tree); |
| 394 | 394 |
|
| 395 | 395 |
} |
| 396 | 396 |
|
| 397 | 397 |
public: |
| 398 | 398 |
|
| 399 | 399 |
/// \brief Constructor |
| 400 | 400 |
/// |
| 401 | 401 |
/// Constructor. |
| 402 | 402 |
MaxMatching(const Graph& graph) |
| 403 | 403 |
: _graph(graph), _matching(0), _status(0), _ear(0), |
| 404 | 404 |
_blossom_set_index(0), _blossom_set(0), _blossom_rep(0), |
| 405 | 405 |
_tree_set_index(0), _tree_set(0) {}
|
| 406 | 406 |
|
| 407 | 407 |
~MaxMatching() {
|
| 408 | 408 |
destroyStructures(); |
| 409 | 409 |
} |
| 410 | 410 |
|
| 411 | 411 |
/// \name Execution control |
| 412 | 412 |
/// The simplest way to execute the algorithm is to use the |
| 413 | 413 |
/// \c run() member function. |
| 414 | 414 |
/// \n |
| 415 | 415 |
|
| 416 | 416 |
/// If you need better control on the execution, you must call |
| 417 | 417 |
/// \ref init(), \ref greedyInit() or \ref matchingInit() |
| 418 | 418 |
/// functions first, then you can start the algorithm with the \ref |
| 419 |
/// |
|
| 419 |
/// startSparse() or startDense() functions. |
|
| 420 | 420 |
|
| 421 | 421 |
///@{
|
| 422 | 422 |
|
| 423 | 423 |
/// \brief Sets the actual matching to the empty matching. |
| 424 | 424 |
/// |
| 425 | 425 |
/// Sets the actual matching to the empty matching. |
| 426 | 426 |
/// |
| 427 | 427 |
void init() {
|
| 428 | 428 |
createStructures(); |
| 429 | 429 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
| 430 | 430 |
_matching->set(n, INVALID); |
| 431 | 431 |
_status->set(n, UNMATCHED); |
| 432 | 432 |
} |
| 433 | 433 |
} |
| 434 | 434 |
|
| 435 | 435 |
///\brief Finds an initial matching in a greedy way |
| 436 | 436 |
/// |
| 437 | 437 |
///It finds an initial matching in a greedy way. |
| 438 | 438 |
void greedyInit() {
|
| 439 | 439 |
createStructures(); |
| 440 | 440 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
| 441 | 441 |
_matching->set(n, INVALID); |
| 442 | 442 |
_status->set(n, UNMATCHED); |
| 443 | 443 |
} |
| 444 | 444 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
| 445 | 445 |
if ((*_matching)[n] == INVALID) {
|
| 446 | 446 |
for (OutArcIt a(_graph, n); a != INVALID ; ++a) {
|
| 447 | 447 |
Node v = _graph.target(a); |
| 448 | 448 |
if ((*_matching)[v] == INVALID && v != n) {
|
| 449 | 449 |
_matching->set(n, a); |
| 450 | 450 |
_status->set(n, MATCHED); |
| 451 | 451 |
_matching->set(v, _graph.oppositeArc(a)); |
| 452 | 452 |
_status->set(v, MATCHED); |
| 453 | 453 |
break; |
| 454 | 454 |
} |
| 455 | 455 |
} |
| 456 | 456 |
} |
| 457 | 457 |
} |
| 458 | 458 |
} |
| 459 | 459 |
|
| 460 | 460 |
|
| 461 | 461 |
/// \brief Initialize the matching from a map containing. |
| 462 | 462 |
/// |
| 463 | 463 |
/// Initialize the matching from a \c bool valued \c Edge map. This |
| 464 | 464 |
/// map must have the property that there are no two incident edges |
| 465 | 465 |
/// with true value, ie. it contains a matching. |
| 466 | 466 |
/// \return %True if the map contains a matching. |
| 467 | 467 |
template <typename MatchingMap> |
| 468 | 468 |
bool matchingInit(const MatchingMap& matching) {
|
| 469 | 469 |
createStructures(); |
| 470 | 470 |
|
| 471 | 471 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
| 472 | 472 |
_matching->set(n, INVALID); |
| 473 | 473 |
_status->set(n, UNMATCHED); |
| 474 | 474 |
} |
| 475 | 475 |
for(EdgeIt e(_graph); e!=INVALID; ++e) {
|
| 476 | 476 |
if (matching[e]) {
|
| 477 | 477 |
|
| 478 | 478 |
Node u = _graph.u(e); |
| 479 | 479 |
if ((*_matching)[u] != INVALID) return false; |
| 480 | 480 |
_matching->set(u, _graph.direct(e, true)); |
| 481 | 481 |
_status->set(u, MATCHED); |
| 482 | 482 |
|
| 483 | 483 |
Node v = _graph.v(e); |
| 484 | 484 |
if ((*_matching)[v] != INVALID) return false; |
| 485 | 485 |
_matching->set(v, _graph.direct(e, false)); |
| 486 | 486 |
_status->set(v, MATCHED); |
| 487 | 487 |
} |
| 488 | 488 |
} |
| 489 | 489 |
return true; |
| 490 | 490 |
} |
| 491 | 491 |
|
| 492 | 492 |
/// \brief Starts Edmonds' algorithm |
| 493 | 493 |
/// |
| 494 | 494 |
/// If runs the original Edmonds' algorithm. |
| 495 | 495 |
void startSparse() {
|
| 496 | 496 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
| 497 | 497 |
if ((*_status)[n] == UNMATCHED) {
|
| 498 | 498 |
(*_blossom_rep)[_blossom_set->insert(n)] = n; |
| 499 | 499 |
_tree_set->insert(n); |
| 500 | 500 |
_status->set(n, EVEN); |
| 501 | 501 |
processSparse(n); |
| 502 | 502 |
} |
| 503 | 503 |
} |
| 504 | 504 |
} |
| 505 | 505 |
|
| 506 | 506 |
/// \brief Starts Edmonds' algorithm. |
| 507 | 507 |
/// |
| 508 | 508 |
/// It runs Edmonds' algorithm with a heuristic of postponing |
| 509 | 509 |
/// shrinks, therefore resulting in a faster algorithm for dense graphs. |
| 510 | 510 |
void startDense() {
|
| 511 | 511 |
for(NodeIt n(_graph); n != INVALID; ++n) {
|
| 512 | 512 |
if ((*_status)[n] == UNMATCHED) {
|
| 513 | 513 |
(*_blossom_rep)[_blossom_set->insert(n)] = n; |
| 514 | 514 |
_tree_set->insert(n); |
| 515 | 515 |
_status->set(n, EVEN); |
| 516 | 516 |
processDense(n); |
| 517 | 517 |
} |
| 518 | 518 |
} |
| 519 | 519 |
} |
| 520 | 520 |
|
| 521 | 521 |
|
| 522 | 522 |
/// \brief Runs Edmonds' algorithm |
| 523 | 523 |
/// |
| 524 | 524 |
/// Runs Edmonds' algorithm for sparse graphs (<tt>m<2*n</tt>) |
| 525 | 525 |
/// or Edmonds' algorithm with a heuristic of |
| 526 | 526 |
/// postponing shrinks for dense graphs. |
| 527 | 527 |
void run() {
|
| 528 | 528 |
if (countEdges(_graph) < 2 * countNodes(_graph)) {
|
| 529 | 529 |
greedyInit(); |
| 530 | 530 |
startSparse(); |
| 531 | 531 |
} else {
|
| 532 | 532 |
init(); |
| 533 | 533 |
startDense(); |
| 534 | 534 |
} |
| 535 | 535 |
} |
| 536 | 536 |
|
| 537 | 537 |
/// @} |
| 538 | 538 |
|
| 539 | 539 |
/// \name Primal solution |
| 540 | 540 |
/// Functions to get the primal solution, ie. the matching. |
| 541 | 541 |
|
| 542 | 542 |
/// @{
|
| 543 | 543 |
|
| 544 | 544 |
///\brief Returns the size of the current matching. |
| 545 | 545 |
/// |
| 546 | 546 |
///Returns the size of the current matching. After \ref |
| 547 | 547 |
///run() it returns the size of the maximum matching in the graph. |
| 548 | 548 |
int matchingSize() const {
|
| 549 | 549 |
int size = 0; |
| 550 | 550 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
| 551 | 551 |
if ((*_matching)[n] != INVALID) {
|
| 552 | 552 |
++size; |
| 553 | 553 |
} |
| 554 | 554 |
} |
| 555 | 555 |
return size / 2; |
| 556 | 556 |
} |
| 557 | 557 |
|
| 558 | 558 |
/// \brief Returns true when the edge is in the matching. |
| 559 | 559 |
/// |
| 560 | 560 |
/// Returns true when the edge is in the matching. |
| 561 | 561 |
bool matching(const Edge& edge) const {
|
| 562 | 562 |
return edge == (*_matching)[_graph.u(edge)]; |
| 563 | 563 |
} |
| 564 | 564 |
|
| 565 | 565 |
/// \brief Returns the matching edge incident to the given node. |
| 566 | 566 |
/// |
| 567 | 567 |
/// Returns the matching edge of a \c node in the actual matching or |
| 568 | 568 |
/// INVALID if the \c node is not covered by the actual matching. |
| 569 | 569 |
Arc matching(const Node& n) const {
|
| 570 | 570 |
return (*_matching)[n]; |
| 571 | 571 |
} |
| 572 | 572 |
|
| 573 | 573 |
///\brief Returns the mate of a node in the actual matching. |
| 574 | 574 |
/// |
| 575 | 575 |
///Returns the mate of a \c node in the actual matching or |
| 576 | 576 |
///INVALID if the \c node is not covered by the actual matching. |
| 577 | 577 |
Node mate(const Node& n) const {
|
| 578 | 578 |
return (*_matching)[n] != INVALID ? |
| 579 | 579 |
_graph.target((*_matching)[n]) : INVALID; |
| 580 | 580 |
} |
| 581 | 581 |
|
| 582 | 582 |
/// @} |
| 583 | 583 |
|
| 584 | 584 |
/// \name Dual solution |
| 585 | 585 |
/// Functions to get the dual solution, ie. the decomposition. |
| 586 | 586 |
|
| 587 | 587 |
/// @{
|
| 588 | 588 |
|
| 589 | 589 |
/// \brief Returns the class of the node in the Edmonds-Gallai |
| 590 | 590 |
/// decomposition. |
| 591 | 591 |
/// |
| 592 | 592 |
/// Returns the class of the node in the Edmonds-Gallai |
| 593 | 593 |
/// decomposition. |
| 594 | 594 |
Status decomposition(const Node& n) const {
|
| 595 | 595 |
return (*_status)[n]; |
| 596 | 596 |
} |
| 597 | 597 |
|
| 598 | 598 |
/// \brief Returns true when the node is in the barrier. |
| 599 | 599 |
/// |
| 600 | 600 |
/// Returns true when the node is in the barrier. |
| 601 | 601 |
bool barrier(const Node& n) const {
|
| 602 | 602 |
return (*_status)[n] == ODD; |
| 603 | 603 |
} |
| 604 | 604 |
|
| 605 | 605 |
/// @} |
| 606 | 606 |
|
| 607 | 607 |
}; |
| 608 | 608 |
|
| 609 | 609 |
/// \ingroup matching |
| 610 | 610 |
/// |
| 611 | 611 |
/// \brief Weighted matching in general graphs |
| 612 | 612 |
/// |
| 613 | 613 |
/// This class provides an efficient implementation of Edmond's |
| 614 | 614 |
/// maximum weighted matching algorithm. The implementation is based |
| 615 | 615 |
/// on extensive use of priority queues and provides |
| 616 | 616 |
/// \f$O(nm\log(n))\f$ time complexity. |
| 617 | 617 |
/// |
| 618 | 618 |
/// The maximum weighted matching problem is to find undirected |
| 619 | 619 |
/// edges in the graph with maximum overall weight and no two of |
| 620 | 620 |
/// them shares their ends. The problem can be formulated with the |
| 621 | 621 |
/// following linear program. |
| 622 | 622 |
/// \f[ \sum_{e \in \delta(u)}x_e \le 1 \quad \forall u\in V\f]
|
| 623 | 623 |
/** \f[ \sum_{e \in \gamma(B)}x_e \le \frac{\vert B \vert - 1}{2}
|
| 624 | 624 |
\quad \forall B\in\mathcal{O}\f] */
|
| 625 | 625 |
/// \f[x_e \ge 0\quad \forall e\in E\f] |
| 626 | 626 |
/// \f[\max \sum_{e\in E}x_ew_e\f]
|
| 627 | 627 |
/// where \f$\delta(X)\f$ is the set of edges incident to a node in |
| 628 | 628 |
/// \f$X\f$, \f$\gamma(X)\f$ is the set of edges with both ends in |
| 629 | 629 |
/// \f$X\f$ and \f$\mathcal{O}\f$ is the set of odd cardinality
|
| 630 | 630 |
/// subsets of the nodes. |
| 631 | 631 |
/// |
| 632 | 632 |
/// The algorithm calculates an optimal matching and a proof of the |
| 633 | 633 |
/// optimality. The solution of the dual problem can be used to check |
| 634 | 634 |
/// the result of the algorithm. The dual linear problem is the |
| 635 | 635 |
/** \f[ y_u + y_v + \sum_{B \in \mathcal{O}, uv \in \gamma(B)}
|
| 636 | 636 |
z_B \ge w_{uv} \quad \forall uv\in E\f] */
|
| 637 | 637 |
/// \f[y_u \ge 0 \quad \forall u \in V\f] |
| 638 | 638 |
/// \f[z_B \ge 0 \quad \forall B \in \mathcal{O}\f]
|
| 639 | 639 |
/** \f[\min \sum_{u \in V}y_u + \sum_{B \in \mathcal{O}}
|
| 640 | 640 |
\frac{\vert B \vert - 1}{2}z_B\f] */
|
| 641 | 641 |
/// |
| 642 | 642 |
/// The algorithm can be executed with \c run() or the \c init() and |
| 643 | 643 |
/// then the \c start() member functions. After it the matching can |
| 644 | 644 |
/// be asked with \c matching() or mate() functions. The dual |
| 645 | 645 |
/// solution can be get with \c nodeValue(), \c blossomNum() and \c |
| 646 | 646 |
/// blossomValue() members and \ref MaxWeightedMatching::BlossomIt |
| 647 | 647 |
/// "BlossomIt" nested class, which is able to iterate on the nodes |
| 648 | 648 |
/// of a blossom. If the value type is integral then the dual |
| 649 | 649 |
/// solution is multiplied by \ref MaxWeightedMatching::dualScale "4". |
| 650 | 650 |
template <typename _Graph, |
| 651 | 651 |
typename _WeightMap = typename _Graph::template EdgeMap<int> > |
| 652 | 652 |
class MaxWeightedMatching {
|
| 653 | 653 |
public: |
| 654 | 654 |
|
| 655 | 655 |
typedef _Graph Graph; |
| 656 | 656 |
typedef _WeightMap WeightMap; |
| 657 | 657 |
typedef typename WeightMap::Value Value; |
| 658 | 658 |
|
| 659 | 659 |
/// \brief Scaling factor for dual solution |
| 660 | 660 |
/// |
| 661 | 661 |
/// Scaling factor for dual solution, it is equal to 4 or 1 |
| 662 | 662 |
/// according to the value type. |
| 663 | 663 |
static const int dualScale = |
| 664 | 664 |
std::numeric_limits<Value>::is_integer ? 4 : 1; |
| 665 | 665 |
|
| 666 | 666 |
typedef typename Graph::template NodeMap<typename Graph::Arc> |
| 667 | 667 |
MatchingMap; |
| 668 | 668 |
|
| 669 | 669 |
private: |
| 670 | 670 |
|
| 671 | 671 |
TEMPLATE_GRAPH_TYPEDEFS(Graph); |
| 672 | 672 |
|
| 673 | 673 |
typedef typename Graph::template NodeMap<Value> NodePotential; |
| 674 | 674 |
typedef std::vector<Node> BlossomNodeList; |
| 675 | 675 |
|
| 676 | 676 |
struct BlossomVariable {
|
| 677 | 677 |
int begin, end; |
| 678 | 678 |
Value value; |
| 679 | 679 |
|
| 680 | 680 |
BlossomVariable(int _begin, int _end, Value _value) |
| 681 | 681 |
: begin(_begin), end(_end), value(_value) {}
|
| 682 | 682 |
|
| 683 | 683 |
}; |
| 684 | 684 |
|
| 685 | 685 |
typedef std::vector<BlossomVariable> BlossomPotential; |
| 686 | 686 |
|
| 687 | 687 |
const Graph& _graph; |
| 688 | 688 |
const WeightMap& _weight; |
| 689 | 689 |
|
| 690 | 690 |
MatchingMap* _matching; |
| 691 | 691 |
|
| 692 | 692 |
NodePotential* _node_potential; |
| 693 | 693 |
|
| 694 | 694 |
BlossomPotential _blossom_potential; |
| 695 | 695 |
BlossomNodeList _blossom_node_list; |
| 696 | 696 |
|
| 697 | 697 |
int _node_num; |
| 698 | 698 |
int _blossom_num; |
| 699 | 699 |
|
| 700 | 700 |
typedef RangeMap<int> IntIntMap; |
| 701 | 701 |
|
| 702 | 702 |
enum Status {
|
| 703 | 703 |
EVEN = -1, MATCHED = 0, ODD = 1, UNMATCHED = -2 |
| 704 | 704 |
}; |
| 705 | 705 |
|
| 706 | 706 |
typedef HeapUnionFind<Value, IntNodeMap> BlossomSet; |
| 707 | 707 |
struct BlossomData {
|
| 708 | 708 |
int tree; |
| 709 | 709 |
Status status; |
| 710 | 710 |
Arc pred, next; |
| 711 | 711 |
Value pot, offset; |
| 712 | 712 |
Node base; |
| 713 | 713 |
}; |
| 714 | 714 |
|
| 715 | 715 |
IntNodeMap *_blossom_index; |
| 716 | 716 |
BlossomSet *_blossom_set; |
| 717 | 717 |
RangeMap<BlossomData>* _blossom_data; |
| 718 | 718 |
|
| 719 | 719 |
IntNodeMap *_node_index; |
| 720 | 720 |
IntArcMap *_node_heap_index; |
| 721 | 721 |
|
| 722 | 722 |
struct NodeData {
|
| 723 | 723 |
|
| 724 | 724 |
NodeData(IntArcMap& node_heap_index) |
| 725 | 725 |
: heap(node_heap_index) {}
|
| 726 | 726 |
|
| 727 | 727 |
int blossom; |
| 728 | 728 |
Value pot; |
| 729 | 729 |
BinHeap<Value, IntArcMap> heap; |
| 730 | 730 |
std::map<int, Arc> heap_index; |
| 731 | 731 |
|
| 732 | 732 |
int tree; |
| 733 | 733 |
}; |
| 734 | 734 |
|
| 735 | 735 |
RangeMap<NodeData>* _node_data; |
| 736 | 736 |
|
| 737 | 737 |
typedef ExtendFindEnum<IntIntMap> TreeSet; |
| 738 | 738 |
|
| 739 | 739 |
IntIntMap *_tree_set_index; |
| 740 | 740 |
TreeSet *_tree_set; |
| 741 | 741 |
|
| 742 | 742 |
IntNodeMap *_delta1_index; |
| 743 | 743 |
BinHeap<Value, IntNodeMap> *_delta1; |
| 744 | 744 |
|
| 745 | 745 |
IntIntMap *_delta2_index; |
| 746 | 746 |
BinHeap<Value, IntIntMap> *_delta2; |
| 747 | 747 |
|
| 748 | 748 |
IntEdgeMap *_delta3_index; |
| 749 | 749 |
BinHeap<Value, IntEdgeMap> *_delta3; |
| 750 | 750 |
|
| 751 | 751 |
IntIntMap *_delta4_index; |
| 752 | 752 |
BinHeap<Value, IntIntMap> *_delta4; |
| 753 | 753 |
|
| 754 | 754 |
Value _delta_sum; |
| 755 | 755 |
|
| 756 | 756 |
void createStructures() {
|
| 757 | 757 |
_node_num = countNodes(_graph); |
| 758 | 758 |
_blossom_num = _node_num * 3 / 2; |
| 759 | 759 |
|
| 760 | 760 |
if (!_matching) {
|
| 761 | 761 |
_matching = new MatchingMap(_graph); |
| 762 | 762 |
} |
| 763 | 763 |
if (!_node_potential) {
|
| 764 | 764 |
_node_potential = new NodePotential(_graph); |
| 765 | 765 |
} |
| 766 | 766 |
if (!_blossom_set) {
|
| 767 | 767 |
_blossom_index = new IntNodeMap(_graph); |
| 768 | 768 |
_blossom_set = new BlossomSet(*_blossom_index); |
| 769 | 769 |
_blossom_data = new RangeMap<BlossomData>(_blossom_num); |
| 770 | 770 |
} |
| 771 | 771 |
|
| 772 | 772 |
if (!_node_index) {
|
| 773 | 773 |
_node_index = new IntNodeMap(_graph); |
| 774 | 774 |
_node_heap_index = new IntArcMap(_graph); |
| 775 | 775 |
_node_data = new RangeMap<NodeData>(_node_num, |
| 776 | 776 |
NodeData(*_node_heap_index)); |
| 777 | 777 |
} |
| 778 | 778 |
|
| 779 | 779 |
if (!_tree_set) {
|
| 780 | 780 |
_tree_set_index = new IntIntMap(_blossom_num); |
| 781 | 781 |
_tree_set = new TreeSet(*_tree_set_index); |
| 782 | 782 |
} |
| 783 | 783 |
if (!_delta1) {
|
| 784 | 784 |
_delta1_index = new IntNodeMap(_graph); |
| 785 | 785 |
_delta1 = new BinHeap<Value, IntNodeMap>(*_delta1_index); |
| 786 | 786 |
} |
| 787 | 787 |
if (!_delta2) {
|
| 788 | 788 |
_delta2_index = new IntIntMap(_blossom_num); |
| 789 | 789 |
_delta2 = new BinHeap<Value, IntIntMap>(*_delta2_index); |
| 790 | 790 |
} |
| 791 | 791 |
if (!_delta3) {
|
| 792 | 792 |
_delta3_index = new IntEdgeMap(_graph); |
| 793 | 793 |
_delta3 = new BinHeap<Value, IntEdgeMap>(*_delta3_index); |
| 794 | 794 |
} |
| 795 | 795 |
if (!_delta4) {
|
| 796 | 796 |
_delta4_index = new IntIntMap(_blossom_num); |
| 797 | 797 |
_delta4 = new BinHeap<Value, IntIntMap>(*_delta4_index); |
| 798 | 798 |
} |
| 799 | 799 |
} |
| 800 | 800 |
|
| 801 | 801 |
void destroyStructures() {
|
| 802 | 802 |
_node_num = countNodes(_graph); |
| 803 | 803 |
_blossom_num = _node_num * 3 / 2; |
| 1 | 1 |
/* -*- C++ -*- |
| 2 | 2 |
* |
| 3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library |
| 4 | 4 |
* |
| 5 | 5 |
* Copyright (C) 2003-2008 |
| 6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
| 7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
| 8 | 8 |
* |
| 9 | 9 |
* Permission to use, modify and distribute this software is granted |
| 10 | 10 |
* provided that this copyright notice appears in all copies. For |
| 11 | 11 |
* precise terms see the accompanying LICENSE file. |
| 12 | 12 |
* |
| 13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
| 14 | 14 |
* express or implied, and with no claim as to its suitability for any |
| 15 | 15 |
* purpose. |
| 16 | 16 |
* |
| 17 | 17 |
*/ |
| 18 | 18 |
|
| 19 | 19 |
#ifndef LEMON_SUURBALLE_H |
| 20 | 20 |
#define LEMON_SUURBALLE_H |
| 21 | 21 |
|
| 22 | 22 |
///\ingroup shortest_path |
| 23 | 23 |
///\file |
| 24 | 24 |
///\brief An algorithm for finding arc-disjoint paths between two |
| 25 | 25 |
/// nodes having minimum total length. |
| 26 | 26 |
|
| 27 | 27 |
#include <vector> |
| 28 | 28 |
#include <lemon/bin_heap.h> |
| 29 | 29 |
#include <lemon/path.h> |
| 30 | 30 |
|
| 31 | 31 |
namespace lemon {
|
| 32 | 32 |
|
| 33 | 33 |
/// \addtogroup shortest_path |
| 34 | 34 |
/// @{
|
| 35 | 35 |
|
| 36 | 36 |
/// \brief Algorithm for finding arc-disjoint paths between two nodes |
| 37 | 37 |
/// having minimum total length. |
| 38 | 38 |
/// |
| 39 | 39 |
/// \ref lemon::Suurballe "Suurballe" implements an algorithm for |
| 40 | 40 |
/// finding arc-disjoint paths having minimum total length (cost) |
| 41 | 41 |
/// from a given source node to a given target node in a digraph. |
| 42 | 42 |
/// |
| 43 | 43 |
/// In fact, this implementation is the specialization of the |
| 44 | 44 |
/// \ref CapacityScaling "successive shortest path" algorithm. |
| 45 | 45 |
/// |
| 46 | 46 |
/// \tparam Digraph The digraph type the algorithm runs on. |
| 47 | 47 |
/// The default value is \c ListDigraph. |
| 48 | 48 |
/// \tparam LengthMap The type of the length (cost) map. |
| 49 | 49 |
/// The default value is <tt>Digraph::ArcMap<int></tt>. |
| 50 | 50 |
/// |
| 51 | 51 |
/// \warning Length values should be \e non-negative \e integers. |
| 52 | 52 |
/// |
| 53 | 53 |
/// \note For finding node-disjoint paths this algorithm can be used |
| 54 |
/// with \ref |
|
| 54 |
/// with \ref SplitNodes. |
|
| 55 | 55 |
#ifdef DOXYGEN |
| 56 | 56 |
template <typename Digraph, typename LengthMap> |
| 57 | 57 |
#else |
| 58 | 58 |
template < typename Digraph = ListDigraph, |
| 59 | 59 |
typename LengthMap = typename Digraph::template ArcMap<int> > |
| 60 | 60 |
#endif |
| 61 | 61 |
class Suurballe |
| 62 | 62 |
{
|
| 63 | 63 |
TEMPLATE_DIGRAPH_TYPEDEFS(Digraph); |
| 64 | 64 |
|
| 65 | 65 |
typedef typename LengthMap::Value Length; |
| 66 | 66 |
typedef ConstMap<Arc, int> ConstArcMap; |
| 67 | 67 |
typedef typename Digraph::template NodeMap<Arc> PredMap; |
| 68 | 68 |
|
| 69 | 69 |
public: |
| 70 | 70 |
|
| 71 | 71 |
/// The type of the flow map. |
| 72 | 72 |
typedef typename Digraph::template ArcMap<int> FlowMap; |
| 73 | 73 |
/// The type of the potential map. |
| 74 | 74 |
typedef typename Digraph::template NodeMap<Length> PotentialMap; |
| 75 | 75 |
/// The type of the path structures. |
| 76 | 76 |
typedef SimplePath<Digraph> Path; |
| 77 | 77 |
|
| 78 | 78 |
private: |
| 79 | 79 |
|
| 80 | 80 |
/// \brief Special implementation of the Dijkstra algorithm |
| 81 | 81 |
/// for finding shortest paths in the residual network. |
| 82 | 82 |
/// |
| 83 | 83 |
/// \ref ResidualDijkstra is a special implementation of the |
| 84 | 84 |
/// \ref Dijkstra algorithm for finding shortest paths in the |
| 85 | 85 |
/// residual network of the digraph with respect to the reduced arc |
| 86 | 86 |
/// lengths and modifying the node potentials according to the |
| 87 | 87 |
/// distance of the nodes. |
| 88 | 88 |
class ResidualDijkstra |
| 89 | 89 |
{
|
| 90 | 90 |
typedef typename Digraph::template NodeMap<int> HeapCrossRef; |
| 91 | 91 |
typedef BinHeap<Length, HeapCrossRef> Heap; |
| 92 | 92 |
|
| 93 | 93 |
private: |
| 94 | 94 |
|
| 95 | 95 |
// The digraph the algorithm runs on |
| 96 | 96 |
const Digraph &_graph; |
| 97 | 97 |
|
| 98 | 98 |
// The main maps |
| 99 | 99 |
const FlowMap &_flow; |
| 100 | 100 |
const LengthMap &_length; |
| 101 | 101 |
PotentialMap &_potential; |
| 102 | 102 |
|
| 103 | 103 |
// The distance map |
| 104 | 104 |
PotentialMap _dist; |
| 105 | 105 |
// The pred arc map |
| 106 | 106 |
PredMap &_pred; |
| 107 | 107 |
// The processed (i.e. permanently labeled) nodes |
| 108 | 108 |
std::vector<Node> _proc_nodes; |
| 109 | 109 |
|
| 110 | 110 |
Node _s; |
| 111 | 111 |
Node _t; |
| 112 | 112 |
|
| 113 | 113 |
public: |
| 114 | 114 |
|
| 115 | 115 |
/// Constructor. |
| 116 | 116 |
ResidualDijkstra( const Digraph &digraph, |
| 117 | 117 |
const FlowMap &flow, |
| 118 | 118 |
const LengthMap &length, |
| 119 | 119 |
PotentialMap &potential, |
| 120 | 120 |
PredMap &pred, |
| 121 | 121 |
Node s, Node t ) : |
| 122 | 122 |
_graph(digraph), _flow(flow), _length(length), _potential(potential), |
| 123 | 123 |
_dist(digraph), _pred(pred), _s(s), _t(t) {}
|
| 124 | 124 |
|
| 125 | 125 |
/// \brief Run the algorithm. It returns \c true if a path is found |
| 126 | 126 |
/// from the source node to the target node. |
| 127 | 127 |
bool run() {
|
| 128 | 128 |
HeapCrossRef heap_cross_ref(_graph, Heap::PRE_HEAP); |
| 129 | 129 |
Heap heap(heap_cross_ref); |
| 130 | 130 |
heap.push(_s, 0); |
| 131 | 131 |
_pred[_s] = INVALID; |
| 132 | 132 |
_proc_nodes.clear(); |
| 133 | 133 |
|
| 134 | 134 |
// Process nodes |
| 135 | 135 |
while (!heap.empty() && heap.top() != _t) {
|
| 136 | 136 |
Node u = heap.top(), v; |
| 137 | 137 |
Length d = heap.prio() + _potential[u], nd; |
| 138 | 138 |
_dist[u] = heap.prio(); |
| 139 | 139 |
heap.pop(); |
| 140 | 140 |
_proc_nodes.push_back(u); |
| 141 | 141 |
|
| 142 | 142 |
// Traverse outgoing arcs |
| 143 | 143 |
for (OutArcIt e(_graph, u); e != INVALID; ++e) {
|
| 144 | 144 |
if (_flow[e] == 0) {
|
| 145 | 145 |
v = _graph.target(e); |
| 146 | 146 |
switch(heap.state(v)) {
|
| 147 | 147 |
case Heap::PRE_HEAP: |
| 148 | 148 |
heap.push(v, d + _length[e] - _potential[v]); |
| 149 | 149 |
_pred[v] = e; |
| 150 | 150 |
break; |
| 151 | 151 |
case Heap::IN_HEAP: |
| 152 | 152 |
nd = d + _length[e] - _potential[v]; |
| 153 | 153 |
if (nd < heap[v]) {
|
| 154 | 154 |
heap.decrease(v, nd); |
| 155 | 155 |
_pred[v] = e; |
| 156 | 156 |
} |
| 157 | 157 |
break; |
| 158 | 158 |
case Heap::POST_HEAP: |
| 159 | 159 |
break; |
| 160 | 160 |
} |
| 161 | 161 |
} |
| 162 | 162 |
} |
| 163 | 163 |
|
| 164 | 164 |
// Traverse incoming arcs |
| 165 | 165 |
for (InArcIt e(_graph, u); e != INVALID; ++e) {
|
| 166 | 166 |
if (_flow[e] == 1) {
|
| 167 | 167 |
v = _graph.source(e); |
| 168 | 168 |
switch(heap.state(v)) {
|
| 169 | 169 |
case Heap::PRE_HEAP: |
| 170 | 170 |
heap.push(v, d - _length[e] - _potential[v]); |
| 171 | 171 |
_pred[v] = e; |
| 172 | 172 |
break; |
| 173 | 173 |
case Heap::IN_HEAP: |
| 174 | 174 |
nd = d - _length[e] - _potential[v]; |
| 175 | 175 |
if (nd < heap[v]) {
|
| 176 | 176 |
heap.decrease(v, nd); |
| 177 | 177 |
_pred[v] = e; |
| 178 | 178 |
} |
| 179 | 179 |
break; |
| 180 | 180 |
case Heap::POST_HEAP: |
| 181 | 181 |
break; |
| 182 | 182 |
} |
| 183 | 183 |
} |
| 184 | 184 |
} |
| 185 | 185 |
} |
| 186 | 186 |
if (heap.empty()) return false; |
| 187 | 187 |
|
| 188 | 188 |
// Update potentials of processed nodes |
| 189 | 189 |
Length t_dist = heap.prio(); |
| 190 | 190 |
for (int i = 0; i < int(_proc_nodes.size()); ++i) |
| 191 | 191 |
_potential[_proc_nodes[i]] += _dist[_proc_nodes[i]] - t_dist; |
| 192 | 192 |
return true; |
| 193 | 193 |
} |
| 194 | 194 |
|
| 195 | 195 |
}; //class ResidualDijkstra |
| 196 | 196 |
|
| 197 | 197 |
private: |
| 198 | 198 |
|
| 199 | 199 |
// The digraph the algorithm runs on |
| 200 | 200 |
const Digraph &_graph; |
| 201 | 201 |
// The length map |
| 202 | 202 |
const LengthMap &_length; |
| 203 | 203 |
|
| 204 | 204 |
// Arc map of the current flow |
| 205 | 205 |
FlowMap *_flow; |
| 206 | 206 |
bool _local_flow; |
| 207 | 207 |
// Node map of the current potentials |
| 208 | 208 |
PotentialMap *_potential; |
| 209 | 209 |
bool _local_potential; |
| 210 | 210 |
|
| 211 | 211 |
// The source node |
| 212 | 212 |
Node _source; |
| 213 | 213 |
// The target node |
| 214 | 214 |
Node _target; |
| 215 | 215 |
|
| 216 | 216 |
// Container to store the found paths |
| 217 | 217 |
std::vector< SimplePath<Digraph> > paths; |
| 218 | 218 |
int _path_num; |
| 219 | 219 |
|
| 220 | 220 |
// The pred arc map |
| 221 | 221 |
PredMap _pred; |
| 222 | 222 |
// Implementation of the Dijkstra algorithm for finding augmenting |
| 223 | 223 |
// shortest paths in the residual network |
| 224 | 224 |
ResidualDijkstra *_dijkstra; |
| 225 | 225 |
|
| 226 | 226 |
public: |
| 227 | 227 |
|
| 228 | 228 |
/// \brief Constructor. |
| 229 | 229 |
/// |
| 230 | 230 |
/// Constructor. |
| 231 | 231 |
/// |
| 232 | 232 |
/// \param digraph The digraph the algorithm runs on. |
| 233 | 233 |
/// \param length The length (cost) values of the arcs. |
| 234 | 234 |
/// \param s The source node. |
| 235 | 235 |
/// \param t The target node. |
| 236 | 236 |
Suurballe( const Digraph &digraph, |
| 237 | 237 |
const LengthMap &length, |
| 238 | 238 |
Node s, Node t ) : |
| 239 | 239 |
_graph(digraph), _length(length), _flow(0), _local_flow(false), |
| 240 | 240 |
_potential(0), _local_potential(false), _source(s), _target(t), |
| 241 | 241 |
_pred(digraph) {}
|
| 242 | 242 |
|
| 243 | 243 |
/// Destructor. |
| 244 | 244 |
~Suurballe() {
|
| 245 | 245 |
if (_local_flow) delete _flow; |
| 246 | 246 |
if (_local_potential) delete _potential; |
| 247 | 247 |
delete _dijkstra; |
| 248 | 248 |
} |
| 249 | 249 |
|
| 250 | 250 |
/// \brief Set the flow map. |
| 251 | 251 |
/// |
| 252 | 252 |
/// This function sets the flow map. |
| 253 | 253 |
/// |
| 254 | 254 |
/// The found flow contains only 0 and 1 values. It is the union of |
| 255 | 255 |
/// the found arc-disjoint paths. |
| 256 | 256 |
/// |
| 257 | 257 |
/// \return \c (*this) |
| 258 | 258 |
Suurballe& flowMap(FlowMap &map) {
|
| 259 | 259 |
if (_local_flow) {
|
| 260 | 260 |
delete _flow; |
| 261 | 261 |
_local_flow = false; |
| 262 | 262 |
} |
| 263 | 263 |
_flow = ↦ |
| 264 | 264 |
return *this; |
| 265 | 265 |
} |
| 266 | 266 |
|
| 267 | 267 |
/// \brief Set the potential map. |
| 268 | 268 |
/// |
| 269 | 269 |
/// This function sets the potential map. |
| 270 | 270 |
/// |
| 271 | 271 |
/// The potentials provide the dual solution of the underlying |
| 272 | 272 |
/// minimum cost flow problem. |
| 273 | 273 |
/// |
| 274 | 274 |
/// \return \c (*this) |
| 275 | 275 |
Suurballe& potentialMap(PotentialMap &map) {
|
| 276 | 276 |
if (_local_potential) {
|
| 277 | 277 |
delete _potential; |
| 278 | 278 |
_local_potential = false; |
| 279 | 279 |
} |
| 280 | 280 |
_potential = ↦ |
| 281 | 281 |
return *this; |
| 282 | 282 |
} |
| 283 | 283 |
|
| 284 | 284 |
/// \name Execution control |
| 285 | 285 |
/// The simplest way to execute the algorithm is to call the run() |
| 286 | 286 |
/// function. |
| 287 | 287 |
/// \n |
| 288 | 288 |
/// If you only need the flow that is the union of the found |
| 289 | 289 |
/// arc-disjoint paths, you may call init() and findFlow(). |
| 290 | 290 |
|
| 291 | 291 |
/// @{
|
| 292 | 292 |
|
| 293 | 293 |
/// \brief Run the algorithm. |
| 294 | 294 |
/// |
| 295 | 295 |
/// This function runs the algorithm. |
| 296 | 296 |
/// |
| 297 | 297 |
/// \param k The number of paths to be found. |
| 298 | 298 |
/// |
| 299 | 299 |
/// \return \c k if there are at least \c k arc-disjoint paths from |
| 300 | 300 |
/// \c s to \c t in the digraph. Otherwise it returns the number of |
| 301 | 301 |
/// arc-disjoint paths found. |
| 302 | 302 |
/// |
| 303 | 303 |
/// \note Apart from the return value, <tt>s.run(k)</tt> is just a |
| 304 | 304 |
/// shortcut of the following code. |
| 305 | 305 |
/// \code |
| 306 | 306 |
/// s.init(); |
| 307 | 307 |
/// s.findFlow(k); |
| 308 | 308 |
/// s.findPaths(); |
| 309 | 309 |
/// \endcode |
| 310 | 310 |
int run(int k = 2) {
|
| 311 | 311 |
init(); |
| 312 | 312 |
findFlow(k); |
| 313 | 313 |
findPaths(); |
| 314 | 314 |
return _path_num; |
| 315 | 315 |
} |
| 316 | 316 |
|
| 317 | 317 |
/// \brief Initialize the algorithm. |
| 318 | 318 |
/// |
| 319 | 319 |
/// This function initializes the algorithm. |
| 320 | 320 |
void init() {
|
| 321 | 321 |
// Initialize maps |
| 322 | 322 |
if (!_flow) {
|
| 323 | 323 |
_flow = new FlowMap(_graph); |
| 324 | 324 |
_local_flow = true; |
| 325 | 325 |
} |
| 326 | 326 |
if (!_potential) {
|
| 327 | 327 |
_potential = new PotentialMap(_graph); |
| 328 | 328 |
_local_potential = true; |
| 329 | 329 |
} |
| 330 | 330 |
for (ArcIt e(_graph); e != INVALID; ++e) (*_flow)[e] = 0; |
| 331 | 331 |
for (NodeIt n(_graph); n != INVALID; ++n) (*_potential)[n] = 0; |
| 332 | 332 |
|
| 333 | 333 |
_dijkstra = new ResidualDijkstra( _graph, *_flow, _length, |
| 334 | 334 |
*_potential, _pred, |
| 335 | 335 |
_source, _target ); |
| 336 | 336 |
} |
| 337 | 337 |
|
| 338 | 338 |
/// \brief Execute the successive shortest path algorithm to find |
| 339 | 339 |
/// an optimal flow. |
| 340 | 340 |
/// |
| 341 | 341 |
/// This function executes the successive shortest path algorithm to |
| 342 | 342 |
/// find a minimum cost flow, which is the union of \c k or less |
| 343 | 343 |
/// arc-disjoint paths. |
| 344 | 344 |
/// |
| 345 | 345 |
/// \return \c k if there are at least \c k arc-disjoint paths from |
| 346 | 346 |
/// \c s to \c t in the digraph. Otherwise it returns the number of |
| 347 | 347 |
/// arc-disjoint paths found. |
| 348 | 348 |
/// |
| 349 | 349 |
/// \pre \ref init() must be called before using this function. |
| 350 | 350 |
int findFlow(int k = 2) {
|
| 351 | 351 |
// Find shortest paths |
| 352 | 352 |
_path_num = 0; |
| 353 | 353 |
while (_path_num < k) {
|
| 354 | 354 |
// Run Dijkstra |
| 355 | 355 |
if (!_dijkstra->run()) break; |
| 356 | 356 |
++_path_num; |
| 357 | 357 |
|
| 358 | 358 |
// Set the flow along the found shortest path |
| 359 | 359 |
Node u = _target; |
| 360 | 360 |
Arc e; |
| 361 | 361 |
while ((e = _pred[u]) != INVALID) {
|
| 362 | 362 |
if (u == _graph.target(e)) {
|
| 363 | 363 |
(*_flow)[e] = 1; |
| 364 | 364 |
u = _graph.source(e); |
| 365 | 365 |
} else {
|
| 366 | 366 |
(*_flow)[e] = 0; |
| 367 | 367 |
u = _graph.target(e); |
| 368 | 368 |
} |
| 369 | 369 |
} |
| 370 | 370 |
} |
| 371 | 371 |
return _path_num; |
| 372 | 372 |
} |
| 373 | 373 |
|
| 374 | 374 |
/// \brief Compute the paths from the flow. |
| 375 | 375 |
/// |
| 376 | 376 |
/// This function computes the paths from the flow. |
| 377 | 377 |
/// |
| 378 | 378 |
/// \pre \ref init() and \ref findFlow() must be called before using |
| 379 | 379 |
/// this function. |
| 380 | 380 |
void findPaths() {
|
| 381 | 381 |
// Create the residual flow map (the union of the paths not found |
| 382 | 382 |
// so far) |
| 383 | 383 |
FlowMap res_flow(_graph); |
| 384 | 384 |
for(ArcIt a(_graph); a != INVALID; ++a) res_flow[a] = (*_flow)[a]; |
| 385 | 385 |
|
| 386 | 386 |
paths.clear(); |
| 387 | 387 |
paths.resize(_path_num); |
| 388 | 388 |
for (int i = 0; i < _path_num; ++i) {
|
| 389 | 389 |
Node n = _source; |
| 390 | 390 |
while (n != _target) {
|
| 391 | 391 |
OutArcIt e(_graph, n); |
| 392 | 392 |
for ( ; res_flow[e] == 0; ++e) ; |
| 393 | 393 |
n = _graph.target(e); |
| 394 | 394 |
paths[i].addBack(e); |
| 395 | 395 |
res_flow[e] = 0; |
| 396 | 396 |
} |
| 397 | 397 |
} |
| 398 | 398 |
} |
| 399 | 399 |
|
| 400 | 400 |
/// @} |
| 401 | 401 |
|
| 402 | 402 |
/// \name Query Functions |
| 403 | 403 |
/// The results of the algorithm can be obtained using these |
| 404 | 404 |
/// functions. |
| 405 | 405 |
/// \n The algorithm should be executed before using them. |
| 406 | 406 |
|
| 407 | 407 |
/// @{
|
| 408 | 408 |
|
| 409 | 409 |
/// \brief Return a const reference to the arc map storing the |
| 410 | 410 |
/// found flow. |
| 411 | 411 |
/// |
| 412 | 412 |
/// This function returns a const reference to the arc map storing |
| 413 | 413 |
/// the flow that is the union of the found arc-disjoint paths. |
| 414 | 414 |
/// |
| 415 | 415 |
/// \pre \ref run() or \ref findFlow() must be called before using |
| 416 | 416 |
/// this function. |
| 417 | 417 |
const FlowMap& flowMap() const {
|
| 418 | 418 |
return *_flow; |
| 419 | 419 |
} |
| 420 | 420 |
|
| 421 | 421 |
/// \brief Return a const reference to the node map storing the |
| 422 | 422 |
/// found potentials (the dual solution). |
| 423 | 423 |
/// |
| 424 | 424 |
/// This function returns a const reference to the node map storing |
| 425 | 425 |
/// the found potentials that provide the dual solution of the |
| 426 | 426 |
/// underlying minimum cost flow problem. |
| 427 | 427 |
/// |
| 428 | 428 |
/// \pre \ref run() or \ref findFlow() must be called before using |
| 429 | 429 |
/// this function. |
| 430 | 430 |
const PotentialMap& potentialMap() const {
|
| 431 | 431 |
return *_potential; |
| 432 | 432 |
} |
| 433 | 433 |
|
| 434 | 434 |
/// \brief Return the flow on the given arc. |
| 435 | 435 |
/// |
| 436 | 436 |
/// This function returns the flow on the given arc. |
| 437 | 437 |
/// It is \c 1 if the arc is involved in one of the found paths, |
| 438 | 438 |
/// otherwise it is \c 0. |
0 comments (0 inline)