1.1 --- a/src/work/jacint/max_save.h Sun Apr 17 18:57:22 2005 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,1136 +0,0 @@
1.4 -// -*- C++ -*-
1.5 -#ifndef LEMON_MAX_FLOW_H
1.6 -#define LEMON_MAX_FLOW_H
1.7 -
1.8 -///\ingroup galgs
1.9 -///\file
1.10 -///\brief Maximum flow algorithm.
1.11 -
1.12 -#define H0 20
1.13 -#define H1 1
1.14 -
1.15 -#include <vector>
1.16 -#include <queue>
1.17 -#include <stack>
1.18 -
1.19 -#include <graph_wrapper.h>
1.20 -#include <bfs_iterator.h>
1.21 -#include <invalid.h>
1.22 -#include <maps.h>
1.23 -#include <for_each_macros.h>
1.24 -
1.25 -/// \file
1.26 -/// \brief Dimacs file format reader.
1.27 -
1.28 -namespace lemon {
1.29 -
1.30 - /// \addtogroup galgs
1.31 - /// @{
1.32 -
1.33 - ///Maximum flow algorithms class.
1.34 -
1.35 - ///This class provides various algorithms for finding a flow of
1.36 - ///maximum value in a directed graph. The \e source node, the \e
1.37 - ///target node, the \e capacity of the edges and the \e starting \e
1.38 - ///flow value of the edges can be passed to the algorithm by the
1.39 - ///constructor. It is possible to change these quantities using the
1.40 - ///functions \ref resetSource, \ref resetTarget, \ref resetCap and
1.41 - ///\ref resetFlow. Before any subsequent runs of any algorithm of
1.42 - ///the class \ref resetFlow should be called, otherwise it will
1.43 - ///start from a maximum flow.
1.44 -
1.45 - ///After running an algorithm of the class, the maximum value of a
1.46 - ///value can be obtained by calling \ref flowValue(). The minimum
1.47 - ///value cut can be written into a \c node map of \c bools by
1.48 - ///calling \ref minCut. (\ref minMinCut and \ref maxMinCut writes
1.49 - ///the inclusionwise minimum and maximum of the minimum value
1.50 - ///cuts, resp.)
1.51 -
1.52 - ///\param Graph The undirected graph type the algorithm runs on.
1.53 - ///\param Num The number type of the capacities and the flow values.
1.54 - ///\param The type of the capacity map.
1.55 - ///\param The type of the flow map.
1.56 -
1.57 - ///\author Marton Makai, Jacint Szabo
1.58 - template <typename Graph, typename Num,
1.59 - typename CapMap=typename Graph::template EdgeMap<Num>,
1.60 - typename FlowMap=typename Graph::template EdgeMap<Num> >
1.61 - class MaxFlow {
1.62 -
1.63 - typedef typename Graph::Node Node;
1.64 - typedef typename Graph::NodeIt NodeIt;
1.65 - typedef typename Graph::OutEdgeIt OutEdgeIt;
1.66 - typedef typename Graph::InEdgeIt InEdgeIt;
1.67 -
1.68 - typedef typename std::vector<std::stack<Node> > VecStack;
1.69 - typedef typename Graph::template NodeMap<Node> NNMap;
1.70 - typedef typename std::vector<Node> VecNode;
1.71 -
1.72 - typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW;
1.73 - typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt;
1.74 - typedef typename ResGW::Edge ResGWEdge;
1.75 - //typedef typename ResGW::template NodeMap<bool> ReachedMap; //fixme
1.76 - typedef typename Graph::template NodeMap<int> ReachedMap;
1.77 -
1.78 - const Graph* g;
1.79 - Node s;
1.80 - Node t;
1.81 - const CapMap* capacity;
1.82 - FlowMap* flow;
1.83 - int n; //the number of nodes of G
1.84 -
1.85 - //level works as a bool map in augmenting path algorithms and is
1.86 - //used by bfs for storing reached information. In preflow, it
1.87 - //shows the levels of nodes.
1.88 - ReachedMap level;
1.89 -
1.90 - //excess is needed only in preflow
1.91 - typename Graph::template NodeMap<Num> excess;
1.92 -
1.93 -
1.94 - //fixme
1.95 - // protected:
1.96 - // MaxFlow() { }
1.97 - // void set(const Graph& _G, Node _s, Node _t, const CapMap& _capacity,
1.98 - // FlowMap& _flow)
1.99 - // {
1.100 - // g=&_G;
1.101 - // s=_s;
1.102 - // t=_t;
1.103 - // capacity=&_capacity;
1.104 - // flow=&_flow;
1.105 - // n=_G.nodeNum;
1.106 - // level.set (_G); //kellene vmi ilyesmi fv
1.107 - // excess(_G,0); //itt is
1.108 - // }
1.109 -
1.110 - public:
1.111 -
1.112 - ///Indicates the property of the starting flow.
1.113 -
1.114 - ///Indicates the property of the starting flow. The meanings:
1.115 - ///- \c ZERO_FLOW: constant zero flow
1.116 - ///- \c GEN_FLOW: any flow, i.e. the sum of the in-flows equals to
1.117 - ///the sum of the out-flows in every node except the source and
1.118 - ///the target.
1.119 - ///- \c PRE_FLOW: any preflow, i.e. the sum of the in-flows is at
1.120 - ///least the sum of the out-flows in every node except the source.
1.121 - enum flowEnum{
1.122 - ZERO_FLOW=0,
1.123 - GEN_FLOW=1,
1.124 - PRE_FLOW=2
1.125 - };
1.126 -
1.127 - MaxFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity,
1.128 - FlowMap& _flow) :
1.129 - g(&_G), s(_s), t(_t), capacity(&_capacity),
1.130 - flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0) {}
1.131 -
1.132 - ///Runs a maximum flow algorithm.
1.133 -
1.134 - ///Runs a preflow algorithm, which is the fastest maximum flow
1.135 - ///algorithm up-to-date. The default for \c fe is ZERO_FLOW.
1.136 - ///\pre The starting flow must be a
1.137 - /// - constant zero flow if \c fe is \c ZERO_FLOW,
1.138 - /// - an arbitary flow if \c fe is \c GEN_FLOW,
1.139 - /// - an arbitary preflow if \c fe is \c PRE_FLOW.
1.140 - void run( flowEnum fe=ZERO_FLOW ) {
1.141 - preflow(fe);
1.142 - }
1.143 -
1.144 - ///Runs a preflow algorithm.
1.145 -
1.146 - ///Runs a preflow algorithm. The preflow algorithms provide the
1.147 - ///fastest way to compute a maximum flow in a directed graph.
1.148 - ///\pre The starting flow must be a
1.149 - /// - constant zero flow if \c fe is \c ZERO_FLOW,
1.150 - /// - an arbitary flow if \c fe is \c GEN_FLOW,
1.151 - /// - an arbitary preflow if \c fe is \c PRE_FLOW.
1.152 - void preflow(flowEnum fe) {
1.153 - preflowPhase1(fe);
1.154 - preflowPhase2();
1.155 - }
1.156 - // Heuristics:
1.157 - // 2 phase
1.158 - // gap
1.159 - // list 'level_list' on the nodes on level i implemented by hand
1.160 - // stack 'active' on the active nodes on level i
1.161 - // runs heuristic 'highest label' for H1*n relabels
1.162 - // runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label'
1.163 - // Parameters H0 and H1 are initialized to 20 and 1.
1.164 -
1.165 - ///Runs the first phase of the preflow algorithm.
1.166 -
1.167 - ///The preflow algorithm consists of two phases, this method runs the
1.168 - ///first phase. After the first phase the maximum flow value and a
1.169 - ///minimum value cut can already be computed, though a maximum flow
1.170 - ///is net yet obtained. So after calling this method \ref flowValue
1.171 - ///and \ref actMinCut gives proper results.
1.172 - ///\warning: \ref minCut, \ref minMinCut and \ref maxMinCut do not
1.173 - ///give minimum value cuts unless calling \ref preflowPhase2.
1.174 - ///\pre The starting flow must be a
1.175 - /// - constant zero flow if \c fe is \c ZERO_FLOW,
1.176 - /// - an arbitary flow if \c fe is \c GEN_FLOW,
1.177 - /// - an arbitary preflow if \c fe is \c PRE_FLOW.
1.178 - void preflowPhase1( flowEnum fe );
1.179 -
1.180 - ///Runs the second phase of the preflow algorithm.
1.181 -
1.182 - ///The preflow algorithm consists of two phases, this method runs
1.183 - ///the second phase. After calling \ref preflowPhase1 and then
1.184 - ///\ref preflowPhase2 the methods \ref flowValue, \ref minCut,
1.185 - ///\ref minMinCut and \ref maxMinCut give proper results.
1.186 - ///\pre \ref preflowPhase1 must be called before.
1.187 - void preflowPhase2();
1.188 -
1.189 - /// Starting from a flow, this method searches for an augmenting path
1.190 - /// according to the Edmonds-Karp algorithm
1.191 - /// and augments the flow on if any.
1.192 - /// The return value shows if the augmentation was successful.
1.193 - bool augmentOnShortestPath();
1.194 -
1.195 - /// Starting from a flow, this method searches for an augmenting blockin
1.196 - /// flow according to Dinits' algorithm and augments the flow on if any.
1.197 - /// The blocking flow is computed in a physically constructed
1.198 - /// residual graph of type \c Mutablegraph.
1.199 - /// The return value show sif the augmentation was succesful.
1.200 - template<typename MutableGraph> bool augmentOnBlockingFlow();
1.201 -
1.202 - /// The same as \c augmentOnBlockingFlow<MutableGraph> but the
1.203 - /// residual graph is not constructed physically.
1.204 - /// The return value shows if the augmentation was succesful.
1.205 - bool augmentOnBlockingFlow2();
1.206 -
1.207 - /// Returns the actual flow value.
1.208 - /// More precisely, it returns the negative excess of s, thus
1.209 - /// this works also for preflows.
1.210 - ///Can be called already after \ref preflowPhase1.
1.211 -
1.212 - Num flowValue() {
1.213 - Num a=0;
1.214 - FOR_EACH_INC_LOC(OutEdgeIt, e, *g, s) a+=(*flow)[e];
1.215 - FOR_EACH_INC_LOC(InEdgeIt, e, *g, s) a-=(*flow)[e];
1.216 - return a;
1.217 - //marci figyu: excess[t] epp ezt adja preflow 0. fazisa utan
1.218 - }
1.219 -
1.220 - ///Returns a minimum value cut after calling \ref preflowPhase1.
1.221 -
1.222 - ///After the first phase of the preflow algorithm the maximum flow
1.223 - ///value and a minimum value cut can already be computed. This
1.224 - ///method can be called after running \ref preflowPhase1 for
1.225 - ///obtaining a minimum value cut.
1.226 - ///\warning: Gives proper result only right after calling \ref
1.227 - ///preflowPhase1.
1.228 - ///\todo We have to make some status variable which shows the actual state
1.229 - /// of the class. This enables us to determine which methods are valid
1.230 - /// for MinCut computation
1.231 - template<typename _CutMap>
1.232 - void actMinCut(_CutMap& M) {
1.233 - NodeIt v;
1.234 - for(g->first(v); g->valid(v); g->next(v)) {
1.235 - if ( level[v] < n ) {
1.236 - M.set(v,false);
1.237 - } else {
1.238 - M.set(v,true);
1.239 - }
1.240 - }
1.241 - }
1.242 -
1.243 - ///Returns the inclusionwise minimum of the minimum value cuts.
1.244 -
1.245 - ///Sets \c M to the characteristic vector of the minimum value cut
1.246 - ///which is inclusionwise minimum. It is computed by processing
1.247 - ///a bfs from the source node \c s in the residual graph.
1.248 - ///\pre M should be a node map of bools initialized to false.
1.249 - ///\pre \c flow must be a maximum flow.
1.250 - template<typename _CutMap>
1.251 - void minMinCut(_CutMap& M) {
1.252 -
1.253 - std::queue<Node> queue;
1.254 -
1.255 - M.set(s,true);
1.256 - queue.push(s);
1.257 -
1.258 - while (!queue.empty()) {
1.259 - Node w=queue.front();
1.260 - queue.pop();
1.261 -
1.262 - OutEdgeIt e;
1.263 - for(g->first(e,w) ; g->valid(e); g->next(e)) {
1.264 - Node v=g->target(e);
1.265 - if (!M[v] && (*flow)[e] < (*capacity)[e] ) {
1.266 - queue.push(v);
1.267 - M.set(v, true);
1.268 - }
1.269 - }
1.270 -
1.271 - InEdgeIt f;
1.272 - for(g->first(f,w) ; g->valid(f); g->next(f)) {
1.273 - Node v=g->source(f);
1.274 - if (!M[v] && (*flow)[f] > 0 ) {
1.275 - queue.push(v);
1.276 - M.set(v, true);
1.277 - }
1.278 - }
1.279 - }
1.280 - }
1.281 -
1.282 -
1.283 - ///Returns the inclusionwise maximum of the minimum value cuts.
1.284 -
1.285 - ///Sets \c M to the characteristic vector of the minimum value cut
1.286 - ///which is inclusionwise maximum. It is computed by processing a
1.287 - ///backward bfs from the target node \c t in the residual graph.
1.288 - ///\pre M should be a node map of bools initialized to false.
1.289 - ///\pre \c flow must be a maximum flow.
1.290 - template<typename _CutMap>
1.291 - void maxMinCut(_CutMap& M) {
1.292 -
1.293 - NodeIt v;
1.294 - for(g->first(v) ; g->valid(v); g->next(v)) {
1.295 - M.set(v, true);
1.296 - }
1.297 -
1.298 - std::queue<Node> queue;
1.299 -
1.300 - M.set(t,false);
1.301 - queue.push(t);
1.302 -
1.303 - while (!queue.empty()) {
1.304 - Node w=queue.front();
1.305 - queue.pop();
1.306 -
1.307 -
1.308 - InEdgeIt e;
1.309 - for(g->first(e,w) ; g->valid(e); g->next(e)) {
1.310 - Node v=g->source(e);
1.311 - if (M[v] && (*flow)[e] < (*capacity)[e] ) {
1.312 - queue.push(v);
1.313 - M.set(v, false);
1.314 - }
1.315 - }
1.316 -
1.317 - OutEdgeIt f;
1.318 - for(g->first(f,w) ; g->valid(f); g->next(f)) {
1.319 - Node v=g->target(f);
1.320 - if (M[v] && (*flow)[f] > 0 ) {
1.321 - queue.push(v);
1.322 - M.set(v, false);
1.323 - }
1.324 - }
1.325 - }
1.326 - }
1.327 -
1.328 -
1.329 - ///Returns a minimum value cut.
1.330 -
1.331 - ///Sets \c M to the characteristic vector of a minimum value cut.
1.332 - ///\pre M should be a node map of bools initialized to false.
1.333 - ///\pre \c flow must be a maximum flow.
1.334 - template<typename CutMap>
1.335 - void minCut(CutMap& M) { minMinCut(M); }
1.336 -
1.337 - ///Resets the source node to \c _s.
1.338 -
1.339 - ///Resets the source node to \c _s.
1.340 - ///
1.341 - void resetSource(Node _s) { s=_s; }
1.342 -
1.343 -
1.344 - ///Resets the target node to \c _t.
1.345 -
1.346 - ///Resets the target node to \c _t.
1.347 - ///
1.348 - void resetTarget(Node _t) { t=_t; }
1.349 -
1.350 - /// Resets the edge map of the capacities to _cap.
1.351 -
1.352 - /// Resets the edge map of the capacities to _cap.
1.353 - ///
1.354 - void resetCap(const CapMap& _cap) { capacity=&_cap; }
1.355 -
1.356 - /// Resets the edge map of the flows to _flow.
1.357 -
1.358 - /// Resets the edge map of the flows to _flow.
1.359 - ///
1.360 - void resetFlow(FlowMap& _flow) { flow=&_flow; }
1.361 -
1.362 -
1.363 - private:
1.364 -
1.365 - int push(Node w, VecStack& active) {
1.366 -
1.367 - int lev=level[w];
1.368 - Num exc=excess[w];
1.369 - int newlevel=n; //bound on the next level of w
1.370 -
1.371 - OutEdgeIt e;
1.372 - for(g->first(e,w); g->valid(e); g->next(e)) {
1.373 -
1.374 - if ( (*flow)[e] >= (*capacity)[e] ) continue;
1.375 - Node v=g->target(e);
1.376 -
1.377 - if( lev > level[v] ) { //Push is allowed now
1.378 -
1.379 - if ( excess[v]<=0 && v!=t && v!=s ) {
1.380 - int lev_v=level[v];
1.381 - active[lev_v].push(v);
1.382 - }
1.383 -
1.384 - Num cap=(*capacity)[e];
1.385 - Num flo=(*flow)[e];
1.386 - Num remcap=cap-flo;
1.387 -
1.388 - if ( remcap >= exc ) { //A nonsaturating push.
1.389 -
1.390 - flow->set(e, flo+exc);
1.391 - excess.set(v, excess[v]+exc);
1.392 - exc=0;
1.393 - break;
1.394 -
1.395 - } else { //A saturating push.
1.396 - flow->set(e, cap);
1.397 - excess.set(v, excess[v]+remcap);
1.398 - exc-=remcap;
1.399 - }
1.400 - } else if ( newlevel > level[v] ) newlevel = level[v];
1.401 - } //for out edges wv
1.402 -
1.403 - if ( exc > 0 ) {
1.404 - InEdgeIt e;
1.405 - for(g->first(e,w); g->valid(e); g->next(e)) {
1.406 -
1.407 - if( (*flow)[e] <= 0 ) continue;
1.408 - Node v=g->source(e);
1.409 -
1.410 - if( lev > level[v] ) { //Push is allowed now
1.411 -
1.412 - if ( excess[v]<=0 && v!=t && v!=s ) {
1.413 - int lev_v=level[v];
1.414 - active[lev_v].push(v);
1.415 - }
1.416 -
1.417 - Num flo=(*flow)[e];
1.418 -
1.419 - if ( flo >= exc ) { //A nonsaturating push.
1.420 -
1.421 - flow->set(e, flo-exc);
1.422 - excess.set(v, excess[v]+exc);
1.423 - exc=0;
1.424 - break;
1.425 - } else { //A saturating push.
1.426 -
1.427 - excess.set(v, excess[v]+flo);
1.428 - exc-=flo;
1.429 - flow->set(e,0);
1.430 - }
1.431 - } else if ( newlevel > level[v] ) newlevel = level[v];
1.432 - } //for in edges vw
1.433 -
1.434 - } // if w still has excess after the out edge for cycle
1.435 -
1.436 - excess.set(w, exc);
1.437 -
1.438 - return newlevel;
1.439 - }
1.440 -
1.441 -
1.442 - void preflowPreproc ( flowEnum fe, VecStack& active,
1.443 - VecNode& level_list, NNMap& left, NNMap& right ) {
1.444 -
1.445 - std::queue<Node> bfs_queue;
1.446 -
1.447 - switch ( fe ) {
1.448 - case ZERO_FLOW:
1.449 - {
1.450 - //Reverse_bfs from t, to find the starting level.
1.451 - level.set(t,0);
1.452 - bfs_queue.push(t);
1.453 -
1.454 - while (!bfs_queue.empty()) {
1.455 -
1.456 - Node v=bfs_queue.front();
1.457 - bfs_queue.pop();
1.458 - int l=level[v]+1;
1.459 -
1.460 - InEdgeIt e;
1.461 - for(g->first(e,v); g->valid(e); g->next(e)) {
1.462 - Node w=g->source(e);
1.463 - if ( level[w] == n && w != s ) {
1.464 - bfs_queue.push(w);
1.465 - Node first=level_list[l];
1.466 - if ( g->valid(first) ) left.set(first,w);
1.467 - right.set(w,first);
1.468 - level_list[l]=w;
1.469 - level.set(w, l);
1.470 - }
1.471 - }
1.472 - }
1.473 -
1.474 - //the starting flow
1.475 - OutEdgeIt e;
1.476 - for(g->first(e,s); g->valid(e); g->next(e))
1.477 - {
1.478 - Num c=(*capacity)[e];
1.479 - if ( c <= 0 ) continue;
1.480 - Node w=g->target(e);
1.481 - if ( level[w] < n ) {
1.482 - if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
1.483 - flow->set(e, c);
1.484 - excess.set(w, excess[w]+c);
1.485 - }
1.486 - }
1.487 - break;
1.488 - }
1.489 -
1.490 - case GEN_FLOW:
1.491 - case PRE_FLOW:
1.492 - {
1.493 - //Reverse_bfs from t in the residual graph,
1.494 - //to find the starting level.
1.495 - level.set(t,0);
1.496 - bfs_queue.push(t);
1.497 -
1.498 - while (!bfs_queue.empty()) {
1.499 -
1.500 - Node v=bfs_queue.front();
1.501 - bfs_queue.pop();
1.502 - int l=level[v]+1;
1.503 -
1.504 - InEdgeIt e;
1.505 - for(g->first(e,v); g->valid(e); g->next(e)) {
1.506 - if ( (*capacity)[e] <= (*flow)[e] ) continue;
1.507 - Node w=g->source(e);
1.508 - if ( level[w] == n && w != s ) {
1.509 - bfs_queue.push(w);
1.510 - Node first=level_list[l];
1.511 - if ( g->valid(first) ) left.set(first,w);
1.512 - right.set(w,first);
1.513 - level_list[l]=w;
1.514 - level.set(w, l);
1.515 - }
1.516 - }
1.517 -
1.518 - OutEdgeIt f;
1.519 - for(g->first(f,v); g->valid(f); g->next(f)) {
1.520 - if ( 0 >= (*flow)[f] ) continue;
1.521 - Node w=g->target(f);
1.522 - if ( level[w] == n && w != s ) {
1.523 - bfs_queue.push(w);
1.524 - Node first=level_list[l];
1.525 - if ( g->valid(first) ) left.set(first,w);
1.526 - right.set(w,first);
1.527 - level_list[l]=w;
1.528 - level.set(w, l);
1.529 - }
1.530 - }
1.531 - }
1.532 -
1.533 -
1.534 - //the starting flow
1.535 - OutEdgeIt e;
1.536 - for(g->first(e,s); g->valid(e); g->next(e))
1.537 - {
1.538 - Num rem=(*capacity)[e]-(*flow)[e];
1.539 - if ( rem <= 0 ) continue;
1.540 - Node w=g->target(e);
1.541 - if ( level[w] < n ) {
1.542 - if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
1.543 - flow->set(e, (*capacity)[e]);
1.544 - excess.set(w, excess[w]+rem);
1.545 - }
1.546 - }
1.547 -
1.548 - InEdgeIt f;
1.549 - for(g->first(f,s); g->valid(f); g->next(f))
1.550 - {
1.551 - if ( (*flow)[f] <= 0 ) continue;
1.552 - Node w=g->source(f);
1.553 - if ( level[w] < n ) {
1.554 - if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
1.555 - excess.set(w, excess[w]+(*flow)[f]);
1.556 - flow->set(f, 0);
1.557 - }
1.558 - }
1.559 - break;
1.560 - } //case PRE_FLOW
1.561 - }
1.562 - } //preflowPreproc
1.563 -
1.564 -
1.565 -
1.566 - void relabel(Node w, int newlevel, VecStack& active,
1.567 - VecNode& level_list, NNMap& left,
1.568 - NNMap& right, int& b, int& k, bool what_heur )
1.569 - {
1.570 -
1.571 - Num lev=level[w];
1.572 -
1.573 - Node right_n=right[w];
1.574 - Node left_n=left[w];
1.575 -
1.576 - //unlacing starts
1.577 - if ( g->valid(right_n) ) {
1.578 - if ( g->valid(left_n) ) {
1.579 - right.set(left_n, right_n);
1.580 - left.set(right_n, left_n);
1.581 - } else {
1.582 - level_list[lev]=right_n;
1.583 - left.set(right_n, INVALID);
1.584 - }
1.585 - } else {
1.586 - if ( g->valid(left_n) ) {
1.587 - right.set(left_n, INVALID);
1.588 - } else {
1.589 - level_list[lev]=INVALID;
1.590 - }
1.591 - }
1.592 - //unlacing ends
1.593 -
1.594 - if ( !g->valid(level_list[lev]) ) {
1.595 -
1.596 - //gapping starts
1.597 - for (int i=lev; i!=k ; ) {
1.598 - Node v=level_list[++i];
1.599 - while ( g->valid(v) ) {
1.600 - level.set(v,n);
1.601 - v=right[v];
1.602 - }
1.603 - level_list[i]=INVALID;
1.604 - if ( !what_heur ) {
1.605 - while ( !active[i].empty() ) {
1.606 - active[i].pop(); //FIXME: ezt szebben kene
1.607 - }
1.608 - }
1.609 - }
1.610 -
1.611 - level.set(w,n);
1.612 - b=lev-1;
1.613 - k=b;
1.614 - //gapping ends
1.615 -
1.616 - } else {
1.617 -
1.618 - if ( newlevel == n ) level.set(w,n);
1.619 - else {
1.620 - level.set(w,++newlevel);
1.621 - active[newlevel].push(w);
1.622 - if ( what_heur ) b=newlevel;
1.623 - if ( k < newlevel ) ++k; //now k=newlevel
1.624 - Node first=level_list[newlevel];
1.625 - if ( g->valid(first) ) left.set(first,w);
1.626 - right.set(w,first);
1.627 - left.set(w,INVALID);
1.628 - level_list[newlevel]=w;
1.629 - }
1.630 - }
1.631 -
1.632 - } //relabel
1.633 -
1.634 -
1.635 - template<typename MapGraphWrapper>
1.636 - class DistanceMap {
1.637 - protected:
1.638 - const MapGraphWrapper* g;
1.639 - typename MapGraphWrapper::template NodeMap<int> dist;
1.640 - public:
1.641 - DistanceMap(MapGraphWrapper& _g) : g(&_g), dist(*g, g->nodeNum()) { }
1.642 - void set(const typename MapGraphWrapper::Node& n, int a) {
1.643 - dist.set(n, a);
1.644 - }
1.645 - int operator[](const typename MapGraphWrapper::Node& n)
1.646 - { return dist[n]; }
1.647 - // int get(const typename MapGraphWrapper::Node& n) const {
1.648 - // return dist[n]; }
1.649 - // bool get(const typename MapGraphWrapper::Edge& e) const {
1.650 - // return (dist.get(g->source(e))<dist.get(g->target(e))); }
1.651 - bool operator[](const typename MapGraphWrapper::Edge& e) const {
1.652 - return (dist[g->source(e)]<dist[g->target(e)]);
1.653 - }
1.654 - };
1.655 -
1.656 - };
1.657 -
1.658 -
1.659 - template <typename Graph, typename Num, typename CapMap, typename FlowMap>
1.660 - void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase1( flowEnum fe )
1.661 - {
1.662 -
1.663 - int heur0=(int)(H0*n); //time while running 'bound decrease'
1.664 - int heur1=(int)(H1*n); //time while running 'highest label'
1.665 - int heur=heur1; //starting time interval (#of relabels)
1.666 - int numrelabel=0;
1.667 -
1.668 - bool what_heur=1;
1.669 - //It is 0 in case 'bound decrease' and 1 in case 'highest label'
1.670 -
1.671 - bool end=false;
1.672 - //Needed for 'bound decrease', true means no active nodes are above bound b.
1.673 -
1.674 - int k=n-2; //bound on the highest level under n containing a node
1.675 - int b=k; //bound on the highest level under n of an active node
1.676 -
1.677 - VecStack active(n);
1.678 -
1.679 - NNMap left(*g, INVALID);
1.680 - NNMap right(*g, INVALID);
1.681 - VecNode level_list(n,INVALID);
1.682 - //List of the nodes in level i<n, set to n.
1.683 -
1.684 - NodeIt v;
1.685 - for(g->first(v); g->valid(v); g->next(v)) level.set(v,n);
1.686 - //setting each node to level n
1.687 -
1.688 - switch ( fe ) {
1.689 - case PRE_FLOW:
1.690 - {
1.691 - //counting the excess
1.692 - NodeIt v;
1.693 - for(g->first(v); g->valid(v); g->next(v)) {
1.694 - Num exc=0;
1.695 -
1.696 - InEdgeIt e;
1.697 - for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e];
1.698 - OutEdgeIt f;
1.699 - for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f];
1.700 -
1.701 - excess.set(v,exc);
1.702 -
1.703 - //putting the active nodes into the stack
1.704 - int lev=level[v];
1.705 - if ( exc > 0 && lev < n && v != t ) active[lev].push(v);
1.706 - }
1.707 - break;
1.708 - }
1.709 - case GEN_FLOW:
1.710 - {
1.711 - //Counting the excess of t
1.712 - Num exc=0;
1.713 -
1.714 - InEdgeIt e;
1.715 - for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e];
1.716 - OutEdgeIt f;
1.717 - for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f];
1.718 -
1.719 - excess.set(t,exc);
1.720 -
1.721 - break;
1.722 - }
1.723 - default:
1.724 - break;
1.725 - }
1.726 -
1.727 - preflowPreproc( fe, active, level_list, left, right );
1.728 - //End of preprocessing
1.729 -
1.730 -
1.731 - //Push/relabel on the highest level active nodes.
1.732 - while ( true ) {
1.733 - if ( b == 0 ) {
1.734 - if ( !what_heur && !end && k > 0 ) {
1.735 - b=k;
1.736 - end=true;
1.737 - } else break;
1.738 - }
1.739 -
1.740 - if ( active[b].empty() ) --b;
1.741 - else {
1.742 - end=false;
1.743 - Node w=active[b].top();
1.744 - active[b].pop();
1.745 - int newlevel=push(w,active);
1.746 - if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list,
1.747 - left, right, b, k, what_heur);
1.748 -
1.749 - ++numrelabel;
1.750 - if ( numrelabel >= heur ) {
1.751 - numrelabel=0;
1.752 - if ( what_heur ) {
1.753 - what_heur=0;
1.754 - heur=heur0;
1.755 - end=false;
1.756 - } else {
1.757 - what_heur=1;
1.758 - heur=heur1;
1.759 - b=k;
1.760 - }
1.761 - }
1.762 - }
1.763 - }
1.764 - }
1.765 -
1.766 -
1.767 -
1.768 - template <typename Graph, typename Num, typename CapMap, typename FlowMap>
1.769 - void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase2()
1.770 - {
1.771 -
1.772 - int k=n-2; //bound on the highest level under n containing a node
1.773 - int b=k; //bound on the highest level under n of an active node
1.774 -
1.775 - VecStack active(n);
1.776 - level.set(s,0);
1.777 - std::queue<Node> bfs_queue;
1.778 - bfs_queue.push(s);
1.779 -
1.780 - while (!bfs_queue.empty()) {
1.781 -
1.782 - Node v=bfs_queue.front();
1.783 - bfs_queue.pop();
1.784 - int l=level[v]+1;
1.785 -
1.786 - InEdgeIt e;
1.787 - for(g->first(e,v); g->valid(e); g->next(e)) {
1.788 - if ( (*capacity)[e] <= (*flow)[e] ) continue;
1.789 - Node u=g->source(e);
1.790 - if ( level[u] >= n ) {
1.791 - bfs_queue.push(u);
1.792 - level.set(u, l);
1.793 - if ( excess[u] > 0 ) active[l].push(u);
1.794 - }
1.795 - }
1.796 -
1.797 - OutEdgeIt f;
1.798 - for(g->first(f,v); g->valid(f); g->next(f)) {
1.799 - if ( 0 >= (*flow)[f] ) continue;
1.800 - Node u=g->target(f);
1.801 - if ( level[u] >= n ) {
1.802 - bfs_queue.push(u);
1.803 - level.set(u, l);
1.804 - if ( excess[u] > 0 ) active[l].push(u);
1.805 - }
1.806 - }
1.807 - }
1.808 - b=n-2;
1.809 -
1.810 - while ( true ) {
1.811 -
1.812 - if ( b == 0 ) break;
1.813 -
1.814 - if ( active[b].empty() ) --b;
1.815 - else {
1.816 - Node w=active[b].top();
1.817 - active[b].pop();
1.818 - int newlevel=push(w,active);
1.819 -
1.820 - //relabel
1.821 - if ( excess[w] > 0 ) {
1.822 - level.set(w,++newlevel);
1.823 - active[newlevel].push(w);
1.824 - b=newlevel;
1.825 - }
1.826 - } // if stack[b] is nonempty
1.827 - } // while(true)
1.828 - }
1.829 -
1.830 -
1.831 -
1.832 - template <typename Graph, typename Num, typename CapMap, typename FlowMap>
1.833 - bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath()
1.834 - {
1.835 - ResGW res_graph(*g, *capacity, *flow);
1.836 - bool _augment=false;
1.837 -
1.838 - //ReachedMap level(res_graph);
1.839 - FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
1.840 - BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
1.841 - bfs.pushAndSetReached(s);
1.842 -
1.843 - typename ResGW::template NodeMap<ResGWEdge> pred(res_graph);
1.844 - pred.set(s, INVALID);
1.845 -
1.846 - typename ResGW::template NodeMap<Num> free(res_graph);
1.847 -
1.848 - //searching for augmenting path
1.849 - while ( !bfs.finished() ) {
1.850 - ResGWOutEdgeIt e=bfs;
1.851 - if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
1.852 - Node v=res_graph.source(e);
1.853 - Node w=res_graph.target(e);
1.854 - pred.set(w, e);
1.855 - if (res_graph.valid(pred[v])) {
1.856 - free.set(w, std::min(free[v], res_graph.resCap(e)));
1.857 - } else {
1.858 - free.set(w, res_graph.resCap(e));
1.859 - }
1.860 - if (res_graph.target(e)==t) { _augment=true; break; }
1.861 - }
1.862 -
1.863 - ++bfs;
1.864 - } //end of searching augmenting path
1.865 -
1.866 - if (_augment) {
1.867 - Node n=t;
1.868 - Num augment_value=free[t];
1.869 - while (res_graph.valid(pred[n])) {
1.870 - ResGWEdge e=pred[n];
1.871 - res_graph.augment(e, augment_value);
1.872 - n=res_graph.source(e);
1.873 - }
1.874 - }
1.875 -
1.876 - return _augment;
1.877 - }
1.878 -
1.879 -
1.880 -
1.881 -
1.882 -
1.883 -
1.884 -
1.885 -
1.886 -
1.887 - template <typename Graph, typename Num, typename CapMap, typename FlowMap>
1.888 - template<typename MutableGraph>
1.889 - bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow()
1.890 - {
1.891 - typedef MutableGraph MG;
1.892 - bool _augment=false;
1.893 -
1.894 - ResGW res_graph(*g, *capacity, *flow);
1.895 -
1.896 - //bfs for distances on the residual graph
1.897 - //ReachedMap level(res_graph);
1.898 - FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
1.899 - BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
1.900 - bfs.pushAndSetReached(s);
1.901 - typename ResGW::template NodeMap<int>
1.902 - dist(res_graph); //filled up with 0's
1.903 -
1.904 - //F will contain the physical copy of the residual graph
1.905 - //with the set of edges which are on shortest paths
1.906 - MG F;
1.907 - typename ResGW::template NodeMap<typename MG::Node>
1.908 - res_graph_to_F(res_graph);
1.909 - {
1.910 - typename ResGW::NodeIt n;
1.911 - for(res_graph.first(n); res_graph.valid(n); res_graph.next(n)) {
1.912 - res_graph_to_F.set(n, F.addNode());
1.913 - }
1.914 - }
1.915 -
1.916 - typename MG::Node sF=res_graph_to_F[s];
1.917 - typename MG::Node tF=res_graph_to_F[t];
1.918 - typename MG::template EdgeMap<ResGWEdge> original_edge(F);
1.919 - typename MG::template EdgeMap<Num> residual_capacity(F);
1.920 -
1.921 - while ( !bfs.finished() ) {
1.922 - ResGWOutEdgeIt e=bfs;
1.923 - if (res_graph.valid(e)) {
1.924 - if (bfs.isBNodeNewlyReached()) {
1.925 - dist.set(res_graph.target(e), dist[res_graph.source(e)]+1);
1.926 - typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.source(e)], res_graph_to_F[res_graph.target(e)]);
1.927 - original_edge.update();
1.928 - original_edge.set(f, e);
1.929 - residual_capacity.update();
1.930 - residual_capacity.set(f, res_graph.resCap(e));
1.931 - } else {
1.932 - if (dist[res_graph.target(e)]==(dist[res_graph.source(e)]+1)) {
1.933 - typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.source(e)], res_graph_to_F[res_graph.target(e)]);
1.934 - original_edge.update();
1.935 - original_edge.set(f, e);
1.936 - residual_capacity.update();
1.937 - residual_capacity.set(f, res_graph.resCap(e));
1.938 - }
1.939 - }
1.940 - }
1.941 - ++bfs;
1.942 - } //computing distances from s in the residual graph
1.943 -
1.944 - bool __augment=true;
1.945 -
1.946 - while (__augment) {
1.947 - __augment=false;
1.948 - //computing blocking flow with dfs
1.949 - DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F);
1.950 - typename MG::template NodeMap<typename MG::Edge> pred(F);
1.951 - pred.set(sF, INVALID);
1.952 - //invalid iterators for sources
1.953 -
1.954 - typename MG::template NodeMap<Num> free(F);
1.955 -
1.956 - dfs.pushAndSetReached(sF);
1.957 - while (!dfs.finished()) {
1.958 - ++dfs;
1.959 - if (F.valid(/*typename MG::OutEdgeIt*/(dfs))) {
1.960 - if (dfs.isBNodeNewlyReached()) {
1.961 - typename MG::Node v=F.aNode(dfs);
1.962 - typename MG::Node w=F.bNode(dfs);
1.963 - pred.set(w, dfs);
1.964 - if (F.valid(pred[v])) {
1.965 - free.set(w, std::min(free[v], residual_capacity[dfs]));
1.966 - } else {
1.967 - free.set(w, residual_capacity[dfs]);
1.968 - }
1.969 - if (w==tF) {
1.970 - __augment=true;
1.971 - _augment=true;
1.972 - break;
1.973 - }
1.974 -
1.975 - } else {
1.976 - F.erase(/*typename MG::OutEdgeIt*/(dfs));
1.977 - }
1.978 - }
1.979 - }
1.980 -
1.981 - if (__augment) {
1.982 - typename MG::Node n=tF;
1.983 - Num augment_value=free[tF];
1.984 - while (F.valid(pred[n])) {
1.985 - typename MG::Edge e=pred[n];
1.986 - res_graph.augment(original_edge[e], augment_value);
1.987 - n=F.source(e);
1.988 - if (residual_capacity[e]==augment_value)
1.989 - F.erase(e);
1.990 - else
1.991 - residual_capacity.set(e, residual_capacity[e]-augment_value);
1.992 - }
1.993 - }
1.994 -
1.995 - }
1.996 -
1.997 - return _augment;
1.998 - }
1.999 -
1.1000 -
1.1001 -
1.1002 -
1.1003 -
1.1004 -
1.1005 - template <typename Graph, typename Num, typename CapMap, typename FlowMap>
1.1006 - bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2()
1.1007 - {
1.1008 - bool _augment=false;
1.1009 -
1.1010 - ResGW res_graph(*g, *capacity, *flow);
1.1011 -
1.1012 - //ReachedMap level(res_graph);
1.1013 - FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
1.1014 - BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
1.1015 -
1.1016 - bfs.pushAndSetReached(s);
1.1017 - DistanceMap<ResGW> dist(res_graph);
1.1018 - while ( !bfs.finished() ) {
1.1019 - ResGWOutEdgeIt e=bfs;
1.1020 - if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
1.1021 - dist.set(res_graph.target(e), dist[res_graph.source(e)]+1);
1.1022 - }
1.1023 - ++bfs;
1.1024 - } //computing distances from s in the residual graph
1.1025 -
1.1026 - //Subgraph containing the edges on some shortest paths
1.1027 - ConstMap<typename ResGW::Node, bool> true_map(true);
1.1028 - typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>,
1.1029 - DistanceMap<ResGW> > FilterResGW;
1.1030 - FilterResGW filter_res_graph(res_graph, true_map, dist);
1.1031 -
1.1032 - //Subgraph, which is able to delete edges which are already
1.1033 - //met by the dfs
1.1034 - typename FilterResGW::template NodeMap<typename FilterResGW::OutEdgeIt>
1.1035 - first_out_edges(filter_res_graph);
1.1036 - typename FilterResGW::NodeIt v;
1.1037 - for(filter_res_graph.first(v); filter_res_graph.valid(v);
1.1038 - filter_res_graph.next(v))
1.1039 - {
1.1040 - typename FilterResGW::OutEdgeIt e;
1.1041 - filter_res_graph.first(e, v);
1.1042 - first_out_edges.set(v, e);
1.1043 - }
1.1044 - typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW::
1.1045 - template NodeMap<typename FilterResGW::OutEdgeIt> > ErasingResGW;
1.1046 - ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges);
1.1047 -
1.1048 - bool __augment=true;
1.1049 -
1.1050 - while (__augment) {
1.1051 -
1.1052 - __augment=false;
1.1053 - //computing blocking flow with dfs
1.1054 - DfsIterator< ErasingResGW,
1.1055 - typename ErasingResGW::template NodeMap<bool> >
1.1056 - dfs(erasing_res_graph);
1.1057 - typename ErasingResGW::
1.1058 - template NodeMap<typename ErasingResGW::OutEdgeIt>
1.1059 - pred(erasing_res_graph);
1.1060 - pred.set(s, INVALID);
1.1061 - //invalid iterators for sources
1.1062 -
1.1063 - typename ErasingResGW::template NodeMap<Num>
1.1064 - free1(erasing_res_graph);
1.1065 -
1.1066 - dfs.pushAndSetReached(
1.1067 - typename ErasingResGW::Node(
1.1068 - typename FilterResGW::Node(
1.1069 - typename ResGW::Node(s)
1.1070 - )
1.1071 - )
1.1072 - );
1.1073 - while (!dfs.finished()) {
1.1074 - ++dfs;
1.1075 - if (erasing_res_graph.valid(
1.1076 - typename ErasingResGW::OutEdgeIt(dfs)))
1.1077 - {
1.1078 - if (dfs.isBNodeNewlyReached()) {
1.1079 -
1.1080 - typename ErasingResGW::Node v=erasing_res_graph.aNode(dfs);
1.1081 - typename ErasingResGW::Node w=erasing_res_graph.bNode(dfs);
1.1082 -
1.1083 - pred.set(w, /*typename ErasingResGW::OutEdgeIt*/(dfs));
1.1084 - if (erasing_res_graph.valid(pred[v])) {
1.1085 - free1.set(w, std::min(free1[v], res_graph.resCap(
1.1086 - typename ErasingResGW::OutEdgeIt(dfs))));
1.1087 - } else {
1.1088 - free1.set(w, res_graph.resCap(
1.1089 - typename ErasingResGW::OutEdgeIt(dfs)));
1.1090 - }
1.1091 -
1.1092 - if (w==t) {
1.1093 - __augment=true;
1.1094 - _augment=true;
1.1095 - break;
1.1096 - }
1.1097 - } else {
1.1098 - erasing_res_graph.erase(dfs);
1.1099 - }
1.1100 - }
1.1101 - }
1.1102 -
1.1103 - if (__augment) {
1.1104 - typename ErasingResGW::Node n=typename FilterResGW::Node(typename ResGW::Node(t));
1.1105 - // typename ResGW::NodeMap<Num> a(res_graph);
1.1106 - // typename ResGW::Node b;
1.1107 - // Num j=a[b];
1.1108 - // typename FilterResGW::NodeMap<Num> a1(filter_res_graph);
1.1109 - // typename FilterResGW::Node b1;
1.1110 - // Num j1=a1[b1];
1.1111 - // typename ErasingResGW::NodeMap<Num> a2(erasing_res_graph);
1.1112 - // typename ErasingResGW::Node b2;
1.1113 - // Num j2=a2[b2];
1.1114 - Num augment_value=free1[n];
1.1115 - while (erasing_res_graph.valid(pred[n])) {
1.1116 - typename ErasingResGW::OutEdgeIt e=pred[n];
1.1117 - res_graph.augment(e, augment_value);
1.1118 - n=erasing_res_graph.source(e);
1.1119 - if (res_graph.resCap(e)==0)
1.1120 - erasing_res_graph.erase(e);
1.1121 - }
1.1122 - }
1.1123 -
1.1124 - } //while (__augment)
1.1125 -
1.1126 - return _augment;
1.1127 - }
1.1128 -
1.1129 -
1.1130 -
1.1131 - /// @}
1.1132 -
1.1133 -} //END OF NAMESPACE LEMON
1.1134 -
1.1135 -#endif //LEMON_MAX_FLOW_H
1.1136 -
1.1137 -
1.1138 -
1.1139 -