[109] | 1 | // -*- C++ -*- |
---|
[372] | 2 | |
---|
[109] | 3 | /* |
---|
| 4 | Heuristics: |
---|
| 5 | 2 phase |
---|
| 6 | gap |
---|
| 7 | list 'level_list' on the nodes on level i implemented by hand |
---|
[451] | 8 | stack 'active' on the active nodes on level i |
---|
[109] | 9 | runs heuristic 'highest label' for H1*n relabels |
---|
[113] | 10 | runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
---|
[109] | 11 | |
---|
[451] | 12 | Parameters H0 and H1 are initialized to 20 and 1. |
---|
[109] | 13 | |
---|
[211] | 14 | Constructors: |
---|
[109] | 15 | |
---|
[372] | 16 | Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if |
---|
| 17 | FlowMap is not constant zero, and should be true if it is |
---|
[109] | 18 | |
---|
| 19 | Members: |
---|
| 20 | |
---|
[211] | 21 | void run() |
---|
[109] | 22 | |
---|
[468] | 23 | Num flowValue() : returns the value of a maximum flow |
---|
[109] | 24 | |
---|
| 25 | void minMinCut(CutMap& M) : sets M to the characteristic vector of the |
---|
[451] | 26 | minimum min cut. M should be a map of bools initialized to false. ??Is it OK? |
---|
[109] | 27 | |
---|
| 28 | void maxMinCut(CutMap& M) : sets M to the characteristic vector of the |
---|
| 29 | maximum min cut. M should be a map of bools initialized to false. |
---|
| 30 | |
---|
| 31 | void minCut(CutMap& M) : sets M to the characteristic vector of |
---|
| 32 | a min cut. M should be a map of bools initialized to false. |
---|
| 33 | |
---|
| 34 | */ |
---|
| 35 | |
---|
[211] | 36 | #ifndef HUGO_PREFLOW_H |
---|
| 37 | #define HUGO_PREFLOW_H |
---|
[109] | 38 | |
---|
| 39 | #define H0 20 |
---|
| 40 | #define H1 1 |
---|
| 41 | |
---|
| 42 | #include <vector> |
---|
| 43 | #include <queue> |
---|
[451] | 44 | #include <stack> |
---|
[109] | 45 | |
---|
| 46 | namespace hugo { |
---|
| 47 | |
---|
[468] | 48 | template <typename Graph, typename Num, |
---|
| 49 | typename CapMap=typename Graph::template EdgeMap<Num>, |
---|
| 50 | typename FlowMap=typename Graph::template EdgeMap<Num> > |
---|
[211] | 51 | class Preflow { |
---|
[109] | 52 | |
---|
[211] | 53 | typedef typename Graph::Node Node; |
---|
[109] | 54 | typedef typename Graph::NodeIt NodeIt; |
---|
| 55 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
---|
| 56 | typedef typename Graph::InEdgeIt InEdgeIt; |
---|
[451] | 57 | |
---|
| 58 | typedef typename std::vector<std::stack<Node> > VecStack; |
---|
| 59 | typedef typename Graph::template NodeMap<Node> NNMap; |
---|
| 60 | typedef typename std::vector<Node> VecNode; |
---|
| 61 | |
---|
[466] | 62 | const Graph* g; |
---|
[211] | 63 | Node s; |
---|
| 64 | Node t; |
---|
[465] | 65 | const CapMap* capacity; |
---|
[451] | 66 | FlowMap* flow; |
---|
| 67 | int n; //the number of nodes of G |
---|
| 68 | typename Graph::template NodeMap<int> level; |
---|
[468] | 69 | typename Graph::template NodeMap<Num> excess; |
---|
[451] | 70 | |
---|
[109] | 71 | |
---|
| 72 | public: |
---|
[451] | 73 | |
---|
| 74 | enum flowEnum{ |
---|
| 75 | ZERO_FLOW=0, |
---|
| 76 | GEN_FLOW=1, |
---|
| 77 | PREFLOW=2 |
---|
| 78 | }; |
---|
| 79 | |
---|
[465] | 80 | Preflow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
---|
[451] | 81 | FlowMap& _flow) : |
---|
[466] | 82 | g(&_G), s(_s), t(_t), capacity(&_capacity), |
---|
[451] | 83 | flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0) {} |
---|
| 84 | |
---|
| 85 | void run() { |
---|
| 86 | preflow( ZERO_FLOW ); |
---|
| 87 | } |
---|
[372] | 88 | |
---|
[451] | 89 | void preflow( flowEnum fe ) { |
---|
| 90 | preflowPhase0(fe); |
---|
| 91 | preflowPhase1(); |
---|
| 92 | } |
---|
| 93 | |
---|
| 94 | void preflowPhase0( flowEnum fe ) { |
---|
[372] | 95 | |
---|
[109] | 96 | int heur0=(int)(H0*n); //time while running 'bound decrease' |
---|
| 97 | int heur1=(int)(H1*n); //time while running 'highest label' |
---|
| 98 | int heur=heur1; //starting time interval (#of relabels) |
---|
[451] | 99 | int numrelabel=0; |
---|
| 100 | |
---|
[109] | 101 | bool what_heur=1; |
---|
[451] | 102 | //It is 0 in case 'bound decrease' and 1 in case 'highest label' |
---|
| 103 | |
---|
[109] | 104 | bool end=false; |
---|
[451] | 105 | //Needed for 'bound decrease', true means no active nodes are above bound b. |
---|
| 106 | |
---|
[109] | 107 | int k=n-2; //bound on the highest level under n containing a node |
---|
| 108 | int b=k; //bound on the highest level under n of an active node |
---|
| 109 | |
---|
[451] | 110 | VecStack active(n); |
---|
| 111 | |
---|
[466] | 112 | NNMap left(*g, INVALID); |
---|
| 113 | NNMap right(*g, INVALID); |
---|
[451] | 114 | VecNode level_list(n,INVALID); |
---|
| 115 | //List of the nodes in level i<n, set to n. |
---|
[109] | 116 | |
---|
[451] | 117 | NodeIt v; |
---|
[466] | 118 | for(g->first(v); g->valid(v); g->next(v)) level.set(v,n); |
---|
[451] | 119 | //setting each node to level n |
---|
| 120 | |
---|
| 121 | switch ( fe ) { |
---|
| 122 | case PREFLOW: |
---|
| 123 | { |
---|
| 124 | //counting the excess |
---|
| 125 | NodeIt v; |
---|
[466] | 126 | for(g->first(v); g->valid(v); g->next(v)) { |
---|
[468] | 127 | Num exc=0; |
---|
[372] | 128 | |
---|
[451] | 129 | InEdgeIt e; |
---|
[466] | 130 | for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
---|
[451] | 131 | OutEdgeIt f; |
---|
[466] | 132 | for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
---|
[451] | 133 | |
---|
| 134 | excess.set(v,exc); |
---|
| 135 | |
---|
| 136 | //putting the active nodes into the stack |
---|
| 137 | int lev=level[v]; |
---|
| 138 | if ( exc > 0 && lev < n && v != t ) active[lev].push(v); |
---|
| 139 | } |
---|
| 140 | break; |
---|
| 141 | } |
---|
| 142 | case GEN_FLOW: |
---|
| 143 | { |
---|
| 144 | //Counting the excess of t |
---|
[468] | 145 | Num exc=0; |
---|
[372] | 146 | |
---|
| 147 | InEdgeIt e; |
---|
[466] | 148 | for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
---|
[451] | 149 | OutEdgeIt f; |
---|
[466] | 150 | for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
---|
[451] | 151 | |
---|
| 152 | excess.set(t,exc); |
---|
| 153 | |
---|
| 154 | break; |
---|
| 155 | } |
---|
[465] | 156 | // default: |
---|
| 157 | // break; |
---|
| 158 | // ZERO_FLOW ize kell |
---|
| 159 | |
---|
[451] | 160 | } |
---|
| 161 | |
---|
| 162 | preflowPreproc( fe, active, level_list, left, right ); |
---|
| 163 | //End of preprocessing |
---|
| 164 | |
---|
| 165 | |
---|
| 166 | //Push/relabel on the highest level active nodes. |
---|
| 167 | while ( true ) { |
---|
| 168 | if ( b == 0 ) { |
---|
| 169 | if ( !what_heur && !end && k > 0 ) { |
---|
| 170 | b=k; |
---|
| 171 | end=true; |
---|
| 172 | } else break; |
---|
| 173 | } |
---|
| 174 | |
---|
| 175 | if ( active[b].empty() ) --b; |
---|
| 176 | else { |
---|
| 177 | end=false; |
---|
| 178 | Node w=active[b].top(); |
---|
| 179 | active[b].pop(); |
---|
| 180 | int newlevel=push(w,active); |
---|
| 181 | if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list, |
---|
| 182 | left, right, b, k, what_heur); |
---|
| 183 | |
---|
| 184 | ++numrelabel; |
---|
| 185 | if ( numrelabel >= heur ) { |
---|
| 186 | numrelabel=0; |
---|
| 187 | if ( what_heur ) { |
---|
| 188 | what_heur=0; |
---|
| 189 | heur=heur0; |
---|
| 190 | end=false; |
---|
| 191 | } else { |
---|
| 192 | what_heur=1; |
---|
| 193 | heur=heur1; |
---|
| 194 | b=k; |
---|
[372] | 195 | } |
---|
[109] | 196 | } |
---|
[451] | 197 | } |
---|
| 198 | } |
---|
| 199 | } |
---|
| 200 | |
---|
| 201 | |
---|
| 202 | void preflowPhase1() { |
---|
| 203 | |
---|
| 204 | int k=n-2; //bound on the highest level under n containing a node |
---|
| 205 | int b=k; //bound on the highest level under n of an active node |
---|
| 206 | |
---|
| 207 | VecStack active(n); |
---|
| 208 | level.set(s,0); |
---|
| 209 | std::queue<Node> bfs_queue; |
---|
| 210 | bfs_queue.push(s); |
---|
| 211 | |
---|
| 212 | while (!bfs_queue.empty()) { |
---|
| 213 | |
---|
| 214 | Node v=bfs_queue.front(); |
---|
| 215 | bfs_queue.pop(); |
---|
| 216 | int l=level[v]+1; |
---|
| 217 | |
---|
| 218 | InEdgeIt e; |
---|
[466] | 219 | for(g->first(e,v); g->valid(e); g->next(e)) { |
---|
[451] | 220 | if ( (*capacity)[e] == (*flow)[e] ) continue; |
---|
[466] | 221 | Node u=g->tail(e); |
---|
[451] | 222 | if ( level[u] >= n ) { |
---|
| 223 | bfs_queue.push(u); |
---|
| 224 | level.set(u, l); |
---|
| 225 | if ( excess[u] > 0 ) active[l].push(u); |
---|
| 226 | } |
---|
[109] | 227 | } |
---|
[451] | 228 | |
---|
| 229 | OutEdgeIt f; |
---|
[466] | 230 | for(g->first(f,v); g->valid(f); g->next(f)) { |
---|
[451] | 231 | if ( 0 == (*flow)[f] ) continue; |
---|
[466] | 232 | Node u=g->head(f); |
---|
[451] | 233 | if ( level[u] >= n ) { |
---|
| 234 | bfs_queue.push(u); |
---|
| 235 | level.set(u, l); |
---|
| 236 | if ( excess[u] > 0 ) active[l].push(u); |
---|
[109] | 237 | } |
---|
| 238 | } |
---|
[372] | 239 | } |
---|
[451] | 240 | b=n-2; |
---|
[372] | 241 | |
---|
[109] | 242 | while ( true ) { |
---|
| 243 | |
---|
[451] | 244 | if ( b == 0 ) break; |
---|
| 245 | |
---|
| 246 | if ( active[b].empty() ) --b; |
---|
[109] | 247 | else { |
---|
[451] | 248 | Node w=active[b].top(); |
---|
| 249 | active[b].pop(); |
---|
| 250 | int newlevel=push(w,active); |
---|
[109] | 251 | |
---|
[451] | 252 | //relabel |
---|
| 253 | if ( excess[w] > 0 ) { |
---|
[109] | 254 | level.set(w,++newlevel); |
---|
[451] | 255 | active[newlevel].push(w); |
---|
[109] | 256 | b=newlevel; |
---|
[451] | 257 | } |
---|
[109] | 258 | } // if stack[b] is nonempty |
---|
| 259 | } // while(true) |
---|
| 260 | } |
---|
| 261 | |
---|
| 262 | |
---|
[451] | 263 | //Returns the maximum value of a flow. |
---|
[468] | 264 | Num flowValue() { |
---|
[451] | 265 | return excess[t]; |
---|
| 266 | } |
---|
[109] | 267 | |
---|
[451] | 268 | //should be used only between preflowPhase0 and preflowPhase1 |
---|
| 269 | template<typename _CutMap> |
---|
| 270 | void actMinCut(_CutMap& M) { |
---|
[211] | 271 | NodeIt v; |
---|
[466] | 272 | for(g->first(v); g->valid(v); g->next(v)) |
---|
| 273 | if ( level[v] < n ) { |
---|
| 274 | M.set(v,false); |
---|
| 275 | } else { |
---|
| 276 | M.set(v,true); |
---|
| 277 | } |
---|
[211] | 278 | } |
---|
[109] | 279 | |
---|
| 280 | |
---|
| 281 | |
---|
| 282 | /* |
---|
| 283 | Returns the minimum min cut, by a bfs from s in the residual graph. |
---|
| 284 | */ |
---|
| 285 | template<typename _CutMap> |
---|
| 286 | void minMinCut(_CutMap& M) { |
---|
| 287 | |
---|
[211] | 288 | std::queue<Node> queue; |
---|
[109] | 289 | |
---|
| 290 | M.set(s,true); |
---|
| 291 | queue.push(s); |
---|
| 292 | |
---|
| 293 | while (!queue.empty()) { |
---|
[211] | 294 | Node w=queue.front(); |
---|
[109] | 295 | queue.pop(); |
---|
| 296 | |
---|
[211] | 297 | OutEdgeIt e; |
---|
[466] | 298 | for(g->first(e,w) ; g->valid(e); g->next(e)) { |
---|
| 299 | Node v=g->head(e); |
---|
[451] | 300 | if (!M[v] && (*flow)[e] < (*capacity)[e] ) { |
---|
[109] | 301 | queue.push(v); |
---|
| 302 | M.set(v, true); |
---|
| 303 | } |
---|
| 304 | } |
---|
| 305 | |
---|
[211] | 306 | InEdgeIt f; |
---|
[466] | 307 | for(g->first(f,w) ; g->valid(f); g->next(f)) { |
---|
| 308 | Node v=g->tail(f); |
---|
[451] | 309 | if (!M[v] && (*flow)[f] > 0 ) { |
---|
[109] | 310 | queue.push(v); |
---|
| 311 | M.set(v, true); |
---|
| 312 | } |
---|
| 313 | } |
---|
| 314 | } |
---|
| 315 | } |
---|
| 316 | |
---|
| 317 | |
---|
| 318 | |
---|
| 319 | /* |
---|
| 320 | Returns the maximum min cut, by a reverse bfs |
---|
| 321 | from t in the residual graph. |
---|
| 322 | */ |
---|
| 323 | |
---|
| 324 | template<typename _CutMap> |
---|
| 325 | void maxMinCut(_CutMap& M) { |
---|
[451] | 326 | |
---|
| 327 | NodeIt v; |
---|
[466] | 328 | for(g->first(v) ; g->valid(v); g->next(v)) { |
---|
[451] | 329 | M.set(v, true); |
---|
| 330 | } |
---|
| 331 | |
---|
[211] | 332 | std::queue<Node> queue; |
---|
[109] | 333 | |
---|
[451] | 334 | M.set(t,false); |
---|
[109] | 335 | queue.push(t); |
---|
| 336 | |
---|
| 337 | while (!queue.empty()) { |
---|
[211] | 338 | Node w=queue.front(); |
---|
[109] | 339 | queue.pop(); |
---|
| 340 | |
---|
[211] | 341 | |
---|
| 342 | InEdgeIt e; |
---|
[466] | 343 | for(g->first(e,w) ; g->valid(e); g->next(e)) { |
---|
| 344 | Node v=g->tail(e); |
---|
[451] | 345 | if (M[v] && (*flow)[e] < (*capacity)[e] ) { |
---|
[109] | 346 | queue.push(v); |
---|
[451] | 347 | M.set(v, false); |
---|
[109] | 348 | } |
---|
| 349 | } |
---|
[211] | 350 | |
---|
| 351 | OutEdgeIt f; |
---|
[466] | 352 | for(g->first(f,w) ; g->valid(f); g->next(f)) { |
---|
| 353 | Node v=g->head(f); |
---|
[451] | 354 | if (M[v] && (*flow)[f] > 0 ) { |
---|
[109] | 355 | queue.push(v); |
---|
[451] | 356 | M.set(v, false); |
---|
[109] | 357 | } |
---|
| 358 | } |
---|
| 359 | } |
---|
| 360 | } |
---|
| 361 | |
---|
| 362 | |
---|
| 363 | template<typename CutMap> |
---|
| 364 | void minCut(CutMap& M) { |
---|
| 365 | minMinCut(M); |
---|
| 366 | } |
---|
| 367 | |
---|
[468] | 368 | void resetTarget(Node _t) {t=_t;} |
---|
| 369 | void resetSource(Node _s) {s=_s;} |
---|
[372] | 370 | |
---|
[468] | 371 | void resetCap(const CapMap& _cap) { |
---|
[451] | 372 | capacity=&_cap; |
---|
| 373 | } |
---|
| 374 | |
---|
[468] | 375 | void resetFlow(FlowMap& _flow) { |
---|
[451] | 376 | flow=&_flow; |
---|
[372] | 377 | } |
---|
| 378 | |
---|
| 379 | |
---|
[451] | 380 | private: |
---|
| 381 | |
---|
| 382 | int push(const Node w, VecStack& active) { |
---|
| 383 | |
---|
| 384 | int lev=level[w]; |
---|
[468] | 385 | Num exc=excess[w]; |
---|
[451] | 386 | int newlevel=n; //bound on the next level of w |
---|
| 387 | |
---|
| 388 | OutEdgeIt e; |
---|
[466] | 389 | for(g->first(e,w); g->valid(e); g->next(e)) { |
---|
[451] | 390 | |
---|
| 391 | if ( (*flow)[e] == (*capacity)[e] ) continue; |
---|
[466] | 392 | Node v=g->head(e); |
---|
[451] | 393 | |
---|
| 394 | if( lev > level[v] ) { //Push is allowed now |
---|
| 395 | |
---|
| 396 | if ( excess[v]==0 && v!=t && v!=s ) { |
---|
| 397 | int lev_v=level[v]; |
---|
| 398 | active[lev_v].push(v); |
---|
| 399 | } |
---|
| 400 | |
---|
[468] | 401 | Num cap=(*capacity)[e]; |
---|
| 402 | Num flo=(*flow)[e]; |
---|
| 403 | Num remcap=cap-flo; |
---|
[451] | 404 | |
---|
| 405 | if ( remcap >= exc ) { //A nonsaturating push. |
---|
| 406 | |
---|
| 407 | flow->set(e, flo+exc); |
---|
| 408 | excess.set(v, excess[v]+exc); |
---|
| 409 | exc=0; |
---|
| 410 | break; |
---|
| 411 | |
---|
| 412 | } else { //A saturating push. |
---|
| 413 | flow->set(e, cap); |
---|
| 414 | excess.set(v, excess[v]+remcap); |
---|
| 415 | exc-=remcap; |
---|
| 416 | } |
---|
| 417 | } else if ( newlevel > level[v] ) newlevel = level[v]; |
---|
| 418 | } //for out edges wv |
---|
| 419 | |
---|
| 420 | if ( exc > 0 ) { |
---|
| 421 | InEdgeIt e; |
---|
[466] | 422 | for(g->first(e,w); g->valid(e); g->next(e)) { |
---|
[451] | 423 | |
---|
| 424 | if( (*flow)[e] == 0 ) continue; |
---|
[466] | 425 | Node v=g->tail(e); |
---|
[451] | 426 | |
---|
| 427 | if( lev > level[v] ) { //Push is allowed now |
---|
| 428 | |
---|
| 429 | if ( excess[v]==0 && v!=t && v!=s ) { |
---|
| 430 | int lev_v=level[v]; |
---|
| 431 | active[lev_v].push(v); |
---|
| 432 | } |
---|
| 433 | |
---|
[468] | 434 | Num flo=(*flow)[e]; |
---|
[451] | 435 | |
---|
| 436 | if ( flo >= exc ) { //A nonsaturating push. |
---|
| 437 | |
---|
| 438 | flow->set(e, flo-exc); |
---|
| 439 | excess.set(v, excess[v]+exc); |
---|
| 440 | exc=0; |
---|
| 441 | break; |
---|
| 442 | } else { //A saturating push. |
---|
| 443 | |
---|
| 444 | excess.set(v, excess[v]+flo); |
---|
| 445 | exc-=flo; |
---|
| 446 | flow->set(e,0); |
---|
| 447 | } |
---|
| 448 | } else if ( newlevel > level[v] ) newlevel = level[v]; |
---|
| 449 | } //for in edges vw |
---|
| 450 | |
---|
| 451 | } // if w still has excess after the out edge for cycle |
---|
| 452 | |
---|
| 453 | excess.set(w, exc); |
---|
| 454 | |
---|
| 455 | return newlevel; |
---|
| 456 | } |
---|
| 457 | |
---|
| 458 | |
---|
| 459 | void preflowPreproc ( flowEnum fe, VecStack& active, |
---|
| 460 | VecNode& level_list, NNMap& left, NNMap& right ) { |
---|
| 461 | |
---|
| 462 | std::queue<Node> bfs_queue; |
---|
| 463 | |
---|
| 464 | switch ( fe ) { |
---|
| 465 | case ZERO_FLOW: |
---|
| 466 | { |
---|
| 467 | //Reverse_bfs from t, to find the starting level. |
---|
| 468 | level.set(t,0); |
---|
| 469 | bfs_queue.push(t); |
---|
| 470 | |
---|
| 471 | while (!bfs_queue.empty()) { |
---|
| 472 | |
---|
| 473 | Node v=bfs_queue.front(); |
---|
| 474 | bfs_queue.pop(); |
---|
| 475 | int l=level[v]+1; |
---|
| 476 | |
---|
| 477 | InEdgeIt e; |
---|
[466] | 478 | for(g->first(e,v); g->valid(e); g->next(e)) { |
---|
| 479 | Node w=g->tail(e); |
---|
[451] | 480 | if ( level[w] == n && w != s ) { |
---|
| 481 | bfs_queue.push(w); |
---|
| 482 | Node first=level_list[l]; |
---|
[466] | 483 | if ( g->valid(first) ) left.set(first,w); |
---|
[451] | 484 | right.set(w,first); |
---|
| 485 | level_list[l]=w; |
---|
| 486 | level.set(w, l); |
---|
| 487 | } |
---|
| 488 | } |
---|
| 489 | } |
---|
| 490 | |
---|
| 491 | //the starting flow |
---|
| 492 | OutEdgeIt e; |
---|
[466] | 493 | for(g->first(e,s); g->valid(e); g->next(e)) |
---|
[451] | 494 | { |
---|
[468] | 495 | Num c=(*capacity)[e]; |
---|
[451] | 496 | if ( c == 0 ) continue; |
---|
[466] | 497 | Node w=g->head(e); |
---|
[451] | 498 | if ( level[w] < n ) { |
---|
| 499 | if ( excess[w] == 0 && w!=t ) active[level[w]].push(w); |
---|
| 500 | flow->set(e, c); |
---|
| 501 | excess.set(w, excess[w]+c); |
---|
| 502 | } |
---|
| 503 | } |
---|
| 504 | break; |
---|
| 505 | } |
---|
| 506 | |
---|
| 507 | case GEN_FLOW: |
---|
| 508 | case PREFLOW: |
---|
| 509 | { |
---|
| 510 | //Reverse_bfs from t in the residual graph, |
---|
| 511 | //to find the starting level. |
---|
| 512 | level.set(t,0); |
---|
| 513 | bfs_queue.push(t); |
---|
| 514 | |
---|
| 515 | while (!bfs_queue.empty()) { |
---|
| 516 | |
---|
| 517 | Node v=bfs_queue.front(); |
---|
| 518 | bfs_queue.pop(); |
---|
| 519 | int l=level[v]+1; |
---|
| 520 | |
---|
| 521 | InEdgeIt e; |
---|
[466] | 522 | for(g->first(e,v); g->valid(e); g->next(e)) { |
---|
[451] | 523 | if ( (*capacity)[e] == (*flow)[e] ) continue; |
---|
[466] | 524 | Node w=g->tail(e); |
---|
[451] | 525 | if ( level[w] == n && w != s ) { |
---|
| 526 | bfs_queue.push(w); |
---|
| 527 | Node first=level_list[l]; |
---|
[466] | 528 | if ( g->valid(first) ) left.set(first,w); |
---|
[451] | 529 | right.set(w,first); |
---|
| 530 | level_list[l]=w; |
---|
| 531 | level.set(w, l); |
---|
| 532 | } |
---|
| 533 | } |
---|
| 534 | |
---|
| 535 | OutEdgeIt f; |
---|
[466] | 536 | for(g->first(f,v); g->valid(f); g->next(f)) { |
---|
[451] | 537 | if ( 0 == (*flow)[f] ) continue; |
---|
[466] | 538 | Node w=g->head(f); |
---|
[451] | 539 | if ( level[w] == n && w != s ) { |
---|
| 540 | bfs_queue.push(w); |
---|
| 541 | Node first=level_list[l]; |
---|
[466] | 542 | if ( g->valid(first) ) left.set(first,w); |
---|
[451] | 543 | right.set(w,first); |
---|
| 544 | level_list[l]=w; |
---|
| 545 | level.set(w, l); |
---|
| 546 | } |
---|
| 547 | } |
---|
| 548 | } |
---|
| 549 | |
---|
| 550 | |
---|
| 551 | //the starting flow |
---|
| 552 | OutEdgeIt e; |
---|
[466] | 553 | for(g->first(e,s); g->valid(e); g->next(e)) |
---|
[451] | 554 | { |
---|
[468] | 555 | Num rem=(*capacity)[e]-(*flow)[e]; |
---|
[451] | 556 | if ( rem == 0 ) continue; |
---|
[466] | 557 | Node w=g->head(e); |
---|
[451] | 558 | if ( level[w] < n ) { |
---|
| 559 | if ( excess[w] == 0 && w!=t ) active[level[w]].push(w); |
---|
| 560 | flow->set(e, (*capacity)[e]); |
---|
| 561 | excess.set(w, excess[w]+rem); |
---|
| 562 | } |
---|
| 563 | } |
---|
| 564 | |
---|
| 565 | InEdgeIt f; |
---|
[466] | 566 | for(g->first(f,s); g->valid(f); g->next(f)) |
---|
[451] | 567 | { |
---|
| 568 | if ( (*flow)[f] == 0 ) continue; |
---|
[466] | 569 | Node w=g->tail(f); |
---|
[451] | 570 | if ( level[w] < n ) { |
---|
| 571 | if ( excess[w] == 0 && w!=t ) active[level[w]].push(w); |
---|
| 572 | excess.set(w, excess[w]+(*flow)[f]); |
---|
| 573 | flow->set(f, 0); |
---|
| 574 | } |
---|
| 575 | } |
---|
| 576 | break; |
---|
| 577 | } //case PREFLOW |
---|
| 578 | } |
---|
| 579 | } //preflowPreproc |
---|
| 580 | |
---|
| 581 | |
---|
| 582 | |
---|
| 583 | void relabel( const Node w, int newlevel, VecStack& active, |
---|
| 584 | VecNode& level_list, NNMap& left, |
---|
| 585 | NNMap& right, int& b, int& k, const bool what_heur ) { |
---|
| 586 | |
---|
[468] | 587 | Num lev=level[w]; |
---|
[451] | 588 | |
---|
| 589 | Node right_n=right[w]; |
---|
| 590 | Node left_n=left[w]; |
---|
| 591 | |
---|
| 592 | //unlacing starts |
---|
[466] | 593 | if ( g->valid(right_n) ) { |
---|
| 594 | if ( g->valid(left_n) ) { |
---|
[451] | 595 | right.set(left_n, right_n); |
---|
| 596 | left.set(right_n, left_n); |
---|
| 597 | } else { |
---|
| 598 | level_list[lev]=right_n; |
---|
| 599 | left.set(right_n, INVALID); |
---|
| 600 | } |
---|
| 601 | } else { |
---|
[466] | 602 | if ( g->valid(left_n) ) { |
---|
[451] | 603 | right.set(left_n, INVALID); |
---|
| 604 | } else { |
---|
| 605 | level_list[lev]=INVALID; |
---|
| 606 | } |
---|
| 607 | } |
---|
| 608 | //unlacing ends |
---|
| 609 | |
---|
[466] | 610 | if ( !g->valid(level_list[lev]) ) { |
---|
[451] | 611 | |
---|
| 612 | //gapping starts |
---|
| 613 | for (int i=lev; i!=k ; ) { |
---|
| 614 | Node v=level_list[++i]; |
---|
[466] | 615 | while ( g->valid(v) ) { |
---|
[451] | 616 | level.set(v,n); |
---|
| 617 | v=right[v]; |
---|
| 618 | } |
---|
| 619 | level_list[i]=INVALID; |
---|
| 620 | if ( !what_heur ) { |
---|
| 621 | while ( !active[i].empty() ) { |
---|
| 622 | active[i].pop(); //FIXME: ezt szebben kene |
---|
| 623 | } |
---|
| 624 | } |
---|
| 625 | } |
---|
| 626 | |
---|
| 627 | level.set(w,n); |
---|
| 628 | b=lev-1; |
---|
| 629 | k=b; |
---|
| 630 | //gapping ends |
---|
| 631 | |
---|
| 632 | } else { |
---|
| 633 | |
---|
| 634 | if ( newlevel == n ) level.set(w,n); |
---|
| 635 | else { |
---|
| 636 | level.set(w,++newlevel); |
---|
| 637 | active[newlevel].push(w); |
---|
| 638 | if ( what_heur ) b=newlevel; |
---|
| 639 | if ( k < newlevel ) ++k; //now k=newlevel |
---|
| 640 | Node first=level_list[newlevel]; |
---|
[466] | 641 | if ( g->valid(first) ) left.set(first,w); |
---|
[451] | 642 | right.set(w,first); |
---|
| 643 | left.set(w,INVALID); |
---|
| 644 | level_list[newlevel]=w; |
---|
| 645 | } |
---|
| 646 | } |
---|
| 647 | |
---|
| 648 | } //relabel |
---|
| 649 | |
---|
[109] | 650 | |
---|
| 651 | }; |
---|
| 652 | |
---|
[174] | 653 | } //namespace hugo |
---|
[109] | 654 | |
---|
[451] | 655 | #endif //HUGO_PREFLOW_H |
---|
[109] | 656 | |
---|
| 657 | |
---|
[174] | 658 | |
---|
| 659 | |
---|