marci@478: // -*- C++ -*-
marci@478:
marci@478: /*
marci@485: Heuristics:
marci@485: 2 phase
marci@485: gap
marci@485: list 'level_list' on the nodes on level i implemented by hand
marci@485: stack 'active' on the active nodes on level i
marci@485: runs heuristic 'highest label' for H1*n relabels
marci@485: runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label'
marci@478:
marci@485: Parameters H0 and H1 are initialized to 20 and 1.
marci@478:
marci@485: Constructors:
marci@478:
marci@485: Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if
marci@485: FlowMap is not constant zero, and should be true if it is
marci@478:
marci@485: Members:
marci@478:
marci@485: void run()
marci@478:
marci@485: Num flowValue() : returns the value of a maximum flow
marci@478:
marci@485: void minMinCut(CutMap& M) : sets M to the characteristic vector of the
marci@485: minimum min cut. M should be a map of bools initialized to false. ??Is it OK?
marci@478:
marci@485: void maxMinCut(CutMap& M) : sets M to the characteristic vector of the
marci@485: maximum min cut. M should be a map of bools initialized to false.
marci@478:
marci@485: void minCut(CutMap& M) : sets M to the characteristic vector of
marci@485: a min cut. M should be a map of bools initialized to false.
marci@478:
marci@478: */
marci@478:
marci@480: #ifndef HUGO_MAX_FLOW_H
marci@480: #define HUGO_MAX_FLOW_H
marci@478:
marci@478: #define H0 20
marci@478: #define H1 1
marci@478:
marci@478: #include <vector>
marci@478: #include <queue>
marci@478: #include <stack>
marci@478:
marci@478: #include <graph_wrapper.h>
marci@478: #include <bfs_iterator.h>
marci@478: #include <invalid.h>
marci@478: #include <maps.h>
marci@478: #include <for_each_macros.h>
marci@478:
marci@488: /// \file
marci@488: /// \brief Dimacs file format reader.
marci@478:
marci@478: namespace hugo {
marci@478:
marci@488:
marci@488: // ///\author Marton Makai, Jacint Szabo
marci@488: /// A class for computing max flows and related quantities.
marci@478: template <typename Graph, typename Num,
marci@478: typename CapMap=typename Graph::template EdgeMap<Num>,
marci@478: typename FlowMap=typename Graph::template EdgeMap<Num> >
marci@478: class MaxFlow {
marci@478:
marci@478: typedef typename Graph::Node Node;
marci@478: typedef typename Graph::NodeIt NodeIt;
marci@478: typedef typename Graph::OutEdgeIt OutEdgeIt;
marci@478: typedef typename Graph::InEdgeIt InEdgeIt;
marci@478:
marci@478: typedef typename std::vector<std::stack<Node> > VecStack;
marci@478: typedef typename Graph::template NodeMap<Node> NNMap;
marci@478: typedef typename std::vector<Node> VecNode;
marci@478:
marci@478: const Graph* g;
marci@478: Node s;
marci@478: Node t;
marci@478: const CapMap* capacity;
marci@478: FlowMap* flow;
marci@478: int n; //the number of nodes of G
marci@478: typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW;
marci@478: typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt;
marci@478: typedef typename ResGW::Edge ResGWEdge;
marci@478: //typedef typename ResGW::template NodeMap<bool> ReachedMap;
marci@478: typedef typename Graph::template NodeMap<int> ReachedMap;
marci@478: ReachedMap level;
marci@478: //level works as a bool map in augmenting path algorithms
marci@478: //and is used by bfs for storing reached information.
marci@478: //In preflow, it shows levels of nodes.
marci@478: //typename Graph::template NodeMap<int> level;
marci@478: typename Graph::template NodeMap<Num> excess;
marci@478:
marci@478: public:
marci@478:
marci@487: ///\todo Document this
marci@478: enum flowEnum{
marci@478: ZERO_FLOW=0,
marci@478: GEN_FLOW=1,
marci@478: PREFLOW=2
marci@478: };
marci@478:
marci@478: MaxFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity,
marci@478: FlowMap& _flow) :
marci@478: g(&_G), s(_s), t(_t), capacity(&_capacity),
marci@478: flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0) {}
marci@478:
marci@485: /// A max flow algorithm is run.
marci@485: ///\pre the flow have to be 0 at the beginning.
marci@478: void run() {
marci@488: preflow(ZERO_FLOW);
marci@478: }
marci@478:
marci@487: /// A preflow algorithm is run.
marci@487: ///\pre The initial edge-map have to be a
marci@487: /// zero flow if \c fe is \c ZERO_FLOW,
marci@487: /// a flow if \c fe is \c GEN_FLOW,
marci@487: /// and a pre-flow it is \c PREFLOW.
marci@488: void preflow(flowEnum fe) {
marci@478: preflowPhase0(fe);
marci@478: preflowPhase1();
marci@478: }
marci@478:
marci@485: /// Run the first phase of preflow, starting from a 0 flow, from a flow,
marci@485: /// or from a preflow, according to \c fe.
marci@478: void preflowPhase0( flowEnum fe );
marci@478:
marci@485: /// Second phase of preflow.
marci@478: void preflowPhase1();
marci@478:
marci@485: /// Starting from a flow, this method searches for an augmenting path
marci@485: /// according to the Edmonds-Karp algorithm
marci@485: /// and augments the flow on if any.
marci@487: /// The return value shows if the augmentation was succesful.
marci@478: bool augmentOnShortestPath();
marci@478:
marci@485: /// Starting from a flow, this method searches for an augmenting blockin
marci@485: /// flow according to Dinits' algorithm and augments the flow on if any.
marci@485: /// The blocking flow is computed in a physically constructed
marci@485: /// residual graph of type \c Mutablegraph.
marci@487: /// The return value show sif the augmentation was succesful.
marci@478: template<typename MutableGraph> bool augmentOnBlockingFlow();
marci@478:
marci@485: /// The same as \c augmentOnBlockingFlow<MutableGraph> but the
marci@485: /// residual graph is not constructed physically.
marci@487: /// The return value shows if the augmentation was succesful.
marci@478: bool augmentOnBlockingFlow2();
marci@478:
marci@478: /// Returns the actual flow value.
marci@478: /// More precisely, it returns the negative excess of s, thus
marci@478: /// this works also for preflows.
marci@478: Num flowValue() {
marci@478: Num a=0;
marci@478: FOR_EACH_INC_LOC(OutEdgeIt, e, *g, s) a+=(*flow)[e];
marci@478: FOR_EACH_INC_LOC(InEdgeIt, e, *g, s) a-=(*flow)[e];
marci@478: return a;
marci@478: }
marci@478:
marci@485: /// Should be used between preflowPhase0 and preflowPhase1.
marci@485: ///\todo We have to make some status variable which shows the actual state
marci@485: /// of the class. This enables us to determine which methods are valid
marci@485: /// for MinCut computation
marci@478: template<typename _CutMap>
marci@478: void actMinCut(_CutMap& M) {
marci@478: NodeIt v;
marci@485: for(g->first(v); g->valid(v); g->next(v)) {
marci@485: if ( level[v] < n ) {
marci@485: M.set(v,false);
marci@485: } else {
marci@485: M.set(v,true);
marci@485: }
marci@478: }
marci@478: }
marci@478:
marci@485: /// The unique inclusionwise minimum cut is computed by
marci@485: /// processing a bfs from s in the residual graph.
marci@485: ///\pre flow have to be a max flow otherwise it will the whole node-set.
marci@478: template<typename _CutMap>
marci@478: void minMinCut(_CutMap& M) {
marci@478:
marci@478: std::queue<Node> queue;
marci@478:
marci@478: M.set(s,true);
marci@478: queue.push(s);
marci@478:
marci@478: while (!queue.empty()) {
marci@478: Node w=queue.front();
marci@478: queue.pop();
marci@478:
marci@478: OutEdgeIt e;
marci@478: for(g->first(e,w) ; g->valid(e); g->next(e)) {
marci@478: Node v=g->head(e);
marci@478: if (!M[v] && (*flow)[e] < (*capacity)[e] ) {
marci@478: queue.push(v);
marci@478: M.set(v, true);
marci@478: }
marci@478: }
marci@478:
marci@478: InEdgeIt f;
marci@478: for(g->first(f,w) ; g->valid(f); g->next(f)) {
marci@478: Node v=g->tail(f);
marci@478: if (!M[v] && (*flow)[f] > 0 ) {
marci@478: queue.push(v);
marci@478: M.set(v, true);
marci@478: }
marci@478: }
marci@478: }
marci@478: }
marci@478:
marci@478:
marci@485: /// The unique inclusionwise maximum cut is computed by
marci@485: /// processing a reverse bfs from t in the residual graph.
marci@485: ///\pre flow have to be a max flow otherwise it will be empty.
marci@478: template<typename _CutMap>
marci@478: void maxMinCut(_CutMap& M) {
marci@478:
marci@478: NodeIt v;
marci@478: for(g->first(v) ; g->valid(v); g->next(v)) {
marci@478: M.set(v, true);
marci@478: }
marci@478:
marci@478: std::queue<Node> queue;
marci@478:
marci@478: M.set(t,false);
marci@478: queue.push(t);
marci@478:
marci@478: while (!queue.empty()) {
marci@478: Node w=queue.front();
marci@478: queue.pop();
marci@478:
marci@478:
marci@478: InEdgeIt e;
marci@478: for(g->first(e,w) ; g->valid(e); g->next(e)) {
marci@478: Node v=g->tail(e);
marci@478: if (M[v] && (*flow)[e] < (*capacity)[e] ) {
marci@478: queue.push(v);
marci@478: M.set(v, false);
marci@478: }
marci@478: }
marci@478:
marci@478: OutEdgeIt f;
marci@478: for(g->first(f,w) ; g->valid(f); g->next(f)) {
marci@478: Node v=g->head(f);
marci@478: if (M[v] && (*flow)[f] > 0 ) {
marci@478: queue.push(v);
marci@478: M.set(v, false);
marci@478: }
marci@478: }
marci@478: }
marci@478: }
marci@478:
marci@478:
marci@485: /// A minimum cut is computed.
marci@478: template<typename CutMap>
marci@485: void minCut(CutMap& M) { minMinCut(M); }
marci@478:
marci@485: ///
marci@487: void resetSource(Node _s) { s=_s; }
marci@487: ///
marci@487: void resetTarget(Node _t) { t=_t; }
marci@478:
marci@485: /// capacity-map is changed.
marci@485: void resetCap(const CapMap& _cap) { capacity=&_cap; }
marci@478:
marci@485: /// flow-map is changed.
marci@485: void resetFlow(FlowMap& _flow) { flow=&_flow; }
marci@478:
marci@478:
marci@478: private:
marci@478:
marci@478: int push(Node w, VecStack& active) {
marci@478:
marci@478: int lev=level[w];
marci@478: Num exc=excess[w];
marci@478: int newlevel=n; //bound on the next level of w
marci@478:
marci@478: OutEdgeIt e;
marci@478: for(g->first(e,w); g->valid(e); g->next(e)) {
marci@478:
marci@478: if ( (*flow)[e] >= (*capacity)[e] ) continue;
marci@478: Node v=g->head(e);
marci@478:
marci@478: if( lev > level[v] ) { //Push is allowed now
marci@478:
marci@478: if ( excess[v]<=0 && v!=t && v!=s ) {
marci@478: int lev_v=level[v];
marci@478: active[lev_v].push(v);
marci@478: }
marci@478:
marci@478: Num cap=(*capacity)[e];
marci@478: Num flo=(*flow)[e];
marci@478: Num remcap=cap-flo;
marci@478:
marci@478: if ( remcap >= exc ) { //A nonsaturating push.
marci@478:
marci@478: flow->set(e, flo+exc);
marci@478: excess.set(v, excess[v]+exc);
marci@478: exc=0;
marci@478: break;
marci@478:
marci@478: } else { //A saturating push.
marci@478: flow->set(e, cap);
marci@478: excess.set(v, excess[v]+remcap);
marci@478: exc-=remcap;
marci@478: }
marci@478: } else if ( newlevel > level[v] ) newlevel = level[v];
marci@478: } //for out edges wv
marci@478:
marci@478: if ( exc > 0 ) {
marci@478: InEdgeIt e;
marci@478: for(g->first(e,w); g->valid(e); g->next(e)) {
marci@478:
marci@478: if( (*flow)[e] <= 0 ) continue;
marci@478: Node v=g->tail(e);
marci@478:
marci@478: if( lev > level[v] ) { //Push is allowed now
marci@478:
marci@478: if ( excess[v]<=0 && v!=t && v!=s ) {
marci@478: int lev_v=level[v];
marci@478: active[lev_v].push(v);
marci@478: }
marci@478:
marci@478: Num flo=(*flow)[e];
marci@478:
marci@478: if ( flo >= exc ) { //A nonsaturating push.
marci@478:
marci@478: flow->set(e, flo-exc);
marci@478: excess.set(v, excess[v]+exc);
marci@478: exc=0;
marci@478: break;
marci@478: } else { //A saturating push.
marci@478:
marci@478: excess.set(v, excess[v]+flo);
marci@478: exc-=flo;
marci@478: flow->set(e,0);
marci@478: }
marci@478: } else if ( newlevel > level[v] ) newlevel = level[v];
marci@478: } //for in edges vw
marci@478:
marci@478: } // if w still has excess after the out edge for cycle
marci@478:
marci@478: excess.set(w, exc);
marci@478:
marci@478: return newlevel;
marci@485: }
marci@478:
marci@478:
marci@478: void preflowPreproc ( flowEnum fe, VecStack& active,
marci@478: VecNode& level_list, NNMap& left, NNMap& right ) {
marci@478:
marci@485: std::queue<Node> bfs_queue;
marci@478:
marci@485: switch ( fe ) {
marci@485: case ZERO_FLOW:
marci@485: {
marci@485: //Reverse_bfs from t, to find the starting level.
marci@485: level.set(t,0);
marci@485: bfs_queue.push(t);
marci@478:
marci@485: while (!bfs_queue.empty()) {
marci@478:
marci@485: Node v=bfs_queue.front();
marci@485: bfs_queue.pop();
marci@485: int l=level[v]+1;
marci@478:
marci@485: InEdgeIt e;
marci@485: for(g->first(e,v); g->valid(e); g->next(e)) {
marci@485: Node w=g->tail(e);
marci@485: if ( level[w] == n && w != s ) {
marci@485: bfs_queue.push(w);
marci@485: Node first=level_list[l];
marci@485: if ( g->valid(first) ) left.set(first,w);
marci@485: right.set(w,first);
marci@485: level_list[l]=w;
marci@485: level.set(w, l);
marci@485: }
marci@485: }
marci@485: }
marci@478:
marci@485: //the starting flow
marci@485: OutEdgeIt e;
marci@485: for(g->first(e,s); g->valid(e); g->next(e))
marci@485: {
marci@485: Num c=(*capacity)[e];
marci@485: if ( c <= 0 ) continue;
marci@485: Node w=g->head(e);
marci@485: if ( level[w] < n ) {
marci@485: if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
marci@485: flow->set(e, c);
marci@485: excess.set(w, excess[w]+c);
marci@485: }
marci@485: }
marci@485: break;
marci@485: }
marci@478:
marci@485: case GEN_FLOW:
marci@485: case PREFLOW:
marci@485: {
marci@485: //Reverse_bfs from t in the residual graph,
marci@485: //to find the starting level.
marci@485: level.set(t,0);
marci@485: bfs_queue.push(t);
marci@478:
marci@485: while (!bfs_queue.empty()) {
marci@478:
marci@485: Node v=bfs_queue.front();
marci@485: bfs_queue.pop();
marci@485: int l=level[v]+1;
marci@478:
marci@485: InEdgeIt e;
marci@485: for(g->first(e,v); g->valid(e); g->next(e)) {
marci@485: if ( (*capacity)[e] <= (*flow)[e] ) continue;
marci@485: Node w=g->tail(e);
marci@485: if ( level[w] == n && w != s ) {
marci@485: bfs_queue.push(w);
marci@485: Node first=level_list[l];
marci@485: if ( g->valid(first) ) left.set(first,w);
marci@485: right.set(w,first);
marci@485: level_list[l]=w;
marci@485: level.set(w, l);
marci@485: }
marci@485: }
marci@478:
marci@485: OutEdgeIt f;
marci@485: for(g->first(f,v); g->valid(f); g->next(f)) {
marci@485: if ( 0 >= (*flow)[f] ) continue;
marci@485: Node w=g->head(f);
marci@485: if ( level[w] == n && w != s ) {
marci@485: bfs_queue.push(w);
marci@485: Node first=level_list[l];
marci@485: if ( g->valid(first) ) left.set(first,w);
marci@485: right.set(w,first);
marci@485: level_list[l]=w;
marci@485: level.set(w, l);
marci@485: }
marci@485: }
marci@485: }
marci@478:
marci@478:
marci@485: //the starting flow
marci@485: OutEdgeIt e;
marci@485: for(g->first(e,s); g->valid(e); g->next(e))
marci@485: {
marci@485: Num rem=(*capacity)[e]-(*flow)[e];
marci@485: if ( rem <= 0 ) continue;
marci@485: Node w=g->head(e);
marci@485: if ( level[w] < n ) {
marci@485: if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
marci@485: flow->set(e, (*capacity)[e]);
marci@485: excess.set(w, excess[w]+rem);
marci@485: }
marci@485: }
marci@478:
marci@485: InEdgeIt f;
marci@485: for(g->first(f,s); g->valid(f); g->next(f))
marci@485: {
marci@485: if ( (*flow)[f] <= 0 ) continue;
marci@485: Node w=g->tail(f);
marci@485: if ( level[w] < n ) {
marci@485: if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
marci@485: excess.set(w, excess[w]+(*flow)[f]);
marci@485: flow->set(f, 0);
marci@485: }
marci@485: }
marci@485: break;
marci@485: } //case PREFLOW
marci@485: }
marci@485: } //preflowPreproc
marci@478:
marci@478:
marci@478:
marci@478: void relabel(Node w, int newlevel, VecStack& active,
marci@478: VecNode& level_list, NNMap& left,
marci@478: NNMap& right, int& b, int& k, bool what_heur )
marci@478: {
marci@478:
marci@478: Num lev=level[w];
marci@478:
marci@478: Node right_n=right[w];
marci@478: Node left_n=left[w];
marci@478:
marci@478: //unlacing starts
marci@478: if ( g->valid(right_n) ) {
marci@478: if ( g->valid(left_n) ) {
marci@478: right.set(left_n, right_n);
marci@478: left.set(right_n, left_n);
marci@478: } else {
marci@478: level_list[lev]=right_n;
marci@478: left.set(right_n, INVALID);
marci@478: }
marci@478: } else {
marci@478: if ( g->valid(left_n) ) {
marci@478: right.set(left_n, INVALID);
marci@478: } else {
marci@478: level_list[lev]=INVALID;
marci@478: }
marci@478: }
marci@478: //unlacing ends
marci@478:
marci@478: if ( !g->valid(level_list[lev]) ) {
marci@478:
marci@478: //gapping starts
marci@478: for (int i=lev; i!=k ; ) {
marci@478: Node v=level_list[++i];
marci@478: while ( g->valid(v) ) {
marci@478: level.set(v,n);
marci@478: v=right[v];
marci@478: }
marci@478: level_list[i]=INVALID;
marci@478: if ( !what_heur ) {
marci@478: while ( !active[i].empty() ) {
marci@478: active[i].pop(); //FIXME: ezt szebben kene
marci@478: }
marci@478: }
marci@478: }
marci@478:
marci@478: level.set(w,n);
marci@478: b=lev-1;
marci@478: k=b;
marci@478: //gapping ends
marci@478:
marci@478: } else {
marci@478:
marci@478: if ( newlevel == n ) level.set(w,n);
marci@478: else {
marci@478: level.set(w,++newlevel);
marci@478: active[newlevel].push(w);
marci@478: if ( what_heur ) b=newlevel;
marci@478: if ( k < newlevel ) ++k; //now k=newlevel
marci@478: Node first=level_list[newlevel];
marci@478: if ( g->valid(first) ) left.set(first,w);
marci@478: right.set(w,first);
marci@478: left.set(w,INVALID);
marci@478: level_list[newlevel]=w;
marci@478: }
marci@478: }
marci@478:
marci@478: } //relabel
marci@478:
marci@478:
marci@478: template<typename MapGraphWrapper>
marci@478: class DistanceMap {
marci@478: protected:
marci@478: const MapGraphWrapper* g;
marci@478: typename MapGraphWrapper::template NodeMap<int> dist;
marci@478: public:
marci@478: DistanceMap(MapGraphWrapper& _g) : g(&_g), dist(*g, g->nodeNum()) { }
marci@478: void set(const typename MapGraphWrapper::Node& n, int a) {
marci@478: dist.set(n, a);
marci@478: }
marci@478: int operator[](const typename MapGraphWrapper::Node& n)
marci@485: { return dist[n]; }
marci@485: // int get(const typename MapGraphWrapper::Node& n) const {
marci@485: // return dist[n]; }
marci@485: // bool get(const typename MapGraphWrapper::Edge& e) const {
marci@485: // return (dist.get(g->tail(e))<dist.get(g->head(e))); }
marci@478: bool operator[](const typename MapGraphWrapper::Edge& e) const {
marci@478: return (dist[g->tail(e)]<dist[g->head(e)]);
marci@478: }
marci@478: };
marci@478:
marci@478: };
marci@478:
marci@478:
marci@478: template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@478: void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase0( flowEnum fe )
marci@478: {
marci@478:
marci@485: int heur0=(int)(H0*n); //time while running 'bound decrease'
marci@485: int heur1=(int)(H1*n); //time while running 'highest label'
marci@485: int heur=heur1; //starting time interval (#of relabels)
marci@485: int numrelabel=0;
marci@478:
marci@485: bool what_heur=1;
marci@485: //It is 0 in case 'bound decrease' and 1 in case 'highest label'
marci@478:
marci@485: bool end=false;
marci@485: //Needed for 'bound decrease', true means no active nodes are above bound b.
marci@478:
marci@485: int k=n-2; //bound on the highest level under n containing a node
marci@485: int b=k; //bound on the highest level under n of an active node
marci@478:
marci@485: VecStack active(n);
marci@478:
marci@485: NNMap left(*g, INVALID);
marci@485: NNMap right(*g, INVALID);
marci@485: VecNode level_list(n,INVALID);
marci@485: //List of the nodes in level i<n, set to n.
marci@478:
marci@485: NodeIt v;
marci@485: for(g->first(v); g->valid(v); g->next(v)) level.set(v,n);
marci@485: //setting each node to level n
marci@478:
marci@485: switch ( fe ) {
marci@485: case PREFLOW:
marci@485: {
marci@485: //counting the excess
marci@485: NodeIt v;
marci@485: for(g->first(v); g->valid(v); g->next(v)) {
marci@478: Num exc=0;
marci@478:
marci@478: InEdgeIt e;
marci@485: for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e];
marci@478: OutEdgeIt f;
marci@485: for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f];
marci@485:
marci@485: excess.set(v,exc);
marci@485:
marci@485: //putting the active nodes into the stack
marci@485: int lev=level[v];
marci@485: if ( exc > 0 && lev < n && v != t ) active[lev].push(v);
marci@478: }
marci@478: break;
marci@478: }
marci@485: case GEN_FLOW:
marci@485: {
marci@485: //Counting the excess of t
marci@485: Num exc=0;
marci@485:
marci@485: InEdgeIt e;
marci@485: for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e];
marci@485: OutEdgeIt f;
marci@485: for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f];
marci@485:
marci@485: excess.set(t,exc);
marci@485:
marci@485: break;
marci@485: }
marci@485: default:
marci@485: break;
marci@485: }
marci@478:
marci@485: preflowPreproc( fe, active, level_list, left, right );
marci@485: //End of preprocessing
marci@478:
marci@478:
marci@485: //Push/relabel on the highest level active nodes.
marci@485: while ( true ) {
marci@485: if ( b == 0 ) {
marci@485: if ( !what_heur && !end && k > 0 ) {
marci@485: b=k;
marci@485: end=true;
marci@485: } else break;
marci@485: }
marci@485:
marci@485: if ( active[b].empty() ) --b;
marci@485: else {
marci@485: end=false;
marci@485: Node w=active[b].top();
marci@485: active[b].pop();
marci@485: int newlevel=push(w,active);
marci@485: if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list,
marci@485: left, right, b, k, what_heur);
marci@485:
marci@485: ++numrelabel;
marci@485: if ( numrelabel >= heur ) {
marci@485: numrelabel=0;
marci@485: if ( what_heur ) {
marci@485: what_heur=0;
marci@485: heur=heur0;
marci@485: end=false;
marci@485: } else {
marci@485: what_heur=1;
marci@485: heur=heur1;
marci@485: b=k;
marci@485: }
marci@478: }
marci@478: }
marci@485: }
marci@485: }
marci@478:
marci@478:
marci@478:
marci@478: template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@478: void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase1()
marci@478: {
marci@478:
marci@485: int k=n-2; //bound on the highest level under n containing a node
marci@485: int b=k; //bound on the highest level under n of an active node
marci@478:
marci@485: VecStack active(n);
marci@485: level.set(s,0);
marci@485: std::queue<Node> bfs_queue;
marci@485: bfs_queue.push(s);
marci@478:
marci@485: while (!bfs_queue.empty()) {
marci@478:
marci@485: Node v=bfs_queue.front();
marci@485: bfs_queue.pop();
marci@485: int l=level[v]+1;
marci@478:
marci@485: InEdgeIt e;
marci@485: for(g->first(e,v); g->valid(e); g->next(e)) {
marci@485: if ( (*capacity)[e] <= (*flow)[e] ) continue;
marci@485: Node u=g->tail(e);
marci@485: if ( level[u] >= n ) {
marci@485: bfs_queue.push(u);
marci@485: level.set(u, l);
marci@485: if ( excess[u] > 0 ) active[l].push(u);
marci@478: }
marci@478: }
marci@485:
marci@485: OutEdgeIt f;
marci@485: for(g->first(f,v); g->valid(f); g->next(f)) {
marci@485: if ( 0 >= (*flow)[f] ) continue;
marci@485: Node u=g->head(f);
marci@485: if ( level[u] >= n ) {
marci@485: bfs_queue.push(u);
marci@485: level.set(u, l);
marci@485: if ( excess[u] > 0 ) active[l].push(u);
marci@485: }
marci@485: }
marci@485: }
marci@485: b=n-2;
marci@478:
marci@485: while ( true ) {
marci@478:
marci@485: if ( b == 0 ) break;
marci@478:
marci@485: if ( active[b].empty() ) --b;
marci@485: else {
marci@485: Node w=active[b].top();
marci@485: active[b].pop();
marci@485: int newlevel=push(w,active);
marci@478:
marci@485: //relabel
marci@485: if ( excess[w] > 0 ) {
marci@485: level.set(w,++newlevel);
marci@485: active[newlevel].push(w);
marci@485: b=newlevel;
marci@485: }
marci@485: } // if stack[b] is nonempty
marci@485: } // while(true)
marci@485: }
marci@478:
marci@478:
marci@478:
marci@478: template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@478: bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath()
marci@478: {
marci@485: ResGW res_graph(*g, *capacity, *flow);
marci@485: bool _augment=false;
marci@478:
marci@485: //ReachedMap level(res_graph);
marci@485: FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@485: BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@485: bfs.pushAndSetReached(s);
marci@478:
marci@485: typename ResGW::template NodeMap<ResGWEdge> pred(res_graph);
marci@485: pred.set(s, INVALID);
marci@478:
marci@485: typename ResGW::template NodeMap<Num> free(res_graph);
marci@478:
marci@485: //searching for augmenting path
marci@485: while ( !bfs.finished() ) {
marci@485: ResGWOutEdgeIt e=bfs;
marci@485: if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
marci@485: Node v=res_graph.tail(e);
marci@485: Node w=res_graph.head(e);
marci@485: pred.set(w, e);
marci@485: if (res_graph.valid(pred[v])) {
marci@485: free.set(w, std::min(free[v], res_graph.resCap(e)));
marci@485: } else {
marci@485: free.set(w, res_graph.resCap(e));
marci@478: }
marci@485: if (res_graph.head(e)==t) { _augment=true; break; }
marci@485: }
marci@478:
marci@485: ++bfs;
marci@485: } //end of searching augmenting path
marci@478:
marci@485: if (_augment) {
marci@485: Node n=t;
marci@485: Num augment_value=free[t];
marci@485: while (res_graph.valid(pred[n])) {
marci@485: ResGWEdge e=pred[n];
marci@485: res_graph.augment(e, augment_value);
marci@485: n=res_graph.tail(e);
marci@478: }
marci@485: }
marci@478:
marci@485: return _augment;
marci@485: }
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478: template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@478: template<typename MutableGraph>
marci@478: bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow()
marci@478: {
marci@485: typedef MutableGraph MG;
marci@485: bool _augment=false;
marci@478:
marci@485: ResGW res_graph(*g, *capacity, *flow);
marci@478:
marci@485: //bfs for distances on the residual graph
marci@485: //ReachedMap level(res_graph);
marci@485: FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@485: BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@485: bfs.pushAndSetReached(s);
marci@485: typename ResGW::template NodeMap<int>
marci@485: dist(res_graph); //filled up with 0's
marci@478:
marci@485: //F will contain the physical copy of the residual graph
marci@485: //with the set of edges which are on shortest paths
marci@485: MG F;
marci@485: typename ResGW::template NodeMap<typename MG::Node>
marci@485: res_graph_to_F(res_graph);
marci@485: {
marci@485: typename ResGW::NodeIt n;
marci@485: for(res_graph.first(n); res_graph.valid(n); res_graph.next(n)) {
marci@485: res_graph_to_F.set(n, F.addNode());
marci@478: }
marci@485: }
marci@478:
marci@485: typename MG::Node sF=res_graph_to_F[s];
marci@485: typename MG::Node tF=res_graph_to_F[t];
marci@485: typename MG::template EdgeMap<ResGWEdge> original_edge(F);
marci@485: typename MG::template EdgeMap<Num> residual_capacity(F);
marci@478:
marci@485: while ( !bfs.finished() ) {
marci@485: ResGWOutEdgeIt e=bfs;
marci@485: if (res_graph.valid(e)) {
marci@485: if (bfs.isBNodeNewlyReached()) {
marci@485: dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1);
marci@485: typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]);
marci@485: original_edge.update();
marci@485: original_edge.set(f, e);
marci@485: residual_capacity.update();
marci@485: residual_capacity.set(f, res_graph.resCap(e));
marci@485: } else {
marci@485: if (dist[res_graph.head(e)]==(dist[res_graph.tail(e)]+1)) {
marci@478: typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]);
marci@478: original_edge.update();
marci@478: original_edge.set(f, e);
marci@478: residual_capacity.update();
marci@478: residual_capacity.set(f, res_graph.resCap(e));
marci@478: }
marci@478: }
marci@485: }
marci@485: ++bfs;
marci@485: } //computing distances from s in the residual graph
marci@478:
marci@485: bool __augment=true;
marci@478:
marci@485: while (__augment) {
marci@485: __augment=false;
marci@485: //computing blocking flow with dfs
marci@485: DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F);
marci@485: typename MG::template NodeMap<typename MG::Edge> pred(F);
marci@485: pred.set(sF, INVALID);
marci@485: //invalid iterators for sources
marci@478:
marci@485: typename MG::template NodeMap<Num> free(F);
marci@478:
marci@485: dfs.pushAndSetReached(sF);
marci@485: while (!dfs.finished()) {
marci@485: ++dfs;
marci@485: if (F.valid(/*typename MG::OutEdgeIt*/(dfs))) {
marci@485: if (dfs.isBNodeNewlyReached()) {
marci@485: typename MG::Node v=F.aNode(dfs);
marci@485: typename MG::Node w=F.bNode(dfs);
marci@485: pred.set(w, dfs);
marci@485: if (F.valid(pred[v])) {
marci@485: free.set(w, std::min(free[v], residual_capacity[dfs]));
marci@485: } else {
marci@485: free.set(w, residual_capacity[dfs]);
marci@485: }
marci@485: if (w==tF) {
marci@485: __augment=true;
marci@485: _augment=true;
marci@485: break;
marci@485: }
marci@478:
marci@485: } else {
marci@485: F.erase(/*typename MG::OutEdgeIt*/(dfs));
marci@485: }
marci@485: }
marci@485: }
marci@485:
marci@485: if (__augment) {
marci@485: typename MG::Node n=tF;
marci@485: Num augment_value=free[tF];
marci@485: while (F.valid(pred[n])) {
marci@485: typename MG::Edge e=pred[n];
marci@485: res_graph.augment(original_edge[e], augment_value);
marci@485: n=F.tail(e);
marci@485: if (residual_capacity[e]==augment_value)
marci@485: F.erase(e);
marci@485: else
marci@485: residual_capacity.set(e, residual_capacity[e]-augment_value);
marci@478: }
marci@485: }
marci@478:
marci@485: }
marci@478:
marci@485: return _augment;
marci@485: }
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478:
marci@478: template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@478: bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2()
marci@478: {
marci@485: bool _augment=false;
marci@478:
marci@485: ResGW res_graph(*g, *capacity, *flow);
marci@478:
marci@485: //ReachedMap level(res_graph);
marci@485: FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@485: BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@478:
marci@485: bfs.pushAndSetReached(s);
marci@485: DistanceMap<ResGW> dist(res_graph);
marci@485: while ( !bfs.finished() ) {
marci@485: ResGWOutEdgeIt e=bfs;
marci@485: if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
marci@485: dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1);
marci@485: }
marci@485: ++bfs;
marci@485: } //computing distances from s in the residual graph
marci@478:
marci@478: //Subgraph containing the edges on some shortest paths
marci@485: ConstMap<typename ResGW::Node, bool> true_map(true);
marci@485: typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>,
marci@485: DistanceMap<ResGW> > FilterResGW;
marci@485: FilterResGW filter_res_graph(res_graph, true_map, dist);
marci@478:
marci@485: //Subgraph, which is able to delete edges which are already
marci@485: //met by the dfs
marci@485: typename FilterResGW::template NodeMap<typename FilterResGW::OutEdgeIt>
marci@485: first_out_edges(filter_res_graph);
marci@485: typename FilterResGW::NodeIt v;
marci@485: for(filter_res_graph.first(v); filter_res_graph.valid(v);
marci@485: filter_res_graph.next(v))
marci@478: {
marci@478: typename FilterResGW::OutEdgeIt e;
marci@478: filter_res_graph.first(e, v);
marci@478: first_out_edges.set(v, e);
marci@478: }
marci@485: typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW::
marci@485: template NodeMap<typename FilterResGW::OutEdgeIt> > ErasingResGW;
marci@485: ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges);
marci@478:
marci@485: bool __augment=true;
marci@478:
marci@485: while (__augment) {
marci@478:
marci@485: __augment=false;
marci@485: //computing blocking flow with dfs
marci@485: DfsIterator< ErasingResGW,
marci@485: typename ErasingResGW::template NodeMap<bool> >
marci@485: dfs(erasing_res_graph);
marci@485: typename ErasingResGW::
marci@485: template NodeMap<typename ErasingResGW::OutEdgeIt>
marci@485: pred(erasing_res_graph);
marci@485: pred.set(s, INVALID);
marci@485: //invalid iterators for sources
marci@478:
marci@485: typename ErasingResGW::template NodeMap<Num>
marci@485: free1(erasing_res_graph);
marci@478:
marci@485: dfs.pushAndSetReached(
marci@485: typename ErasingResGW::Node(
marci@485: typename FilterResGW::Node(
marci@485: typename ResGW::Node(s)
marci@485: )
marci@485: )
marci@485: );
marci@485: while (!dfs.finished()) {
marci@485: ++dfs;
marci@485: if (erasing_res_graph.valid(
marci@485: typename ErasingResGW::OutEdgeIt(dfs)))
marci@478: {
marci@478: if (dfs.isBNodeNewlyReached()) {
marci@478:
marci@478: typename ErasingResGW::Node v=erasing_res_graph.aNode(dfs);
marci@478: typename ErasingResGW::Node w=erasing_res_graph.bNode(dfs);
marci@478:
marci@478: pred.set(w, /*typename ErasingResGW::OutEdgeIt*/(dfs));
marci@478: if (erasing_res_graph.valid(pred[v])) {
marci@478: free1.set(w, std::min(free1[v], res_graph.resCap(
marci@485: typename ErasingResGW::OutEdgeIt(dfs))));
marci@478: } else {
marci@478: free1.set(w, res_graph.resCap(
marci@485: typename ErasingResGW::OutEdgeIt(dfs)));
marci@478: }
marci@478:
marci@478: if (w==t) {
marci@478: __augment=true;
marci@478: _augment=true;
marci@478: break;
marci@478: }
marci@478: } else {
marci@478: erasing_res_graph.erase(dfs);
marci@478: }
marci@478: }
marci@485: }
marci@478:
marci@485: if (__augment) {
marci@485: typename ErasingResGW::Node n=typename FilterResGW::Node(typename ResGW::Node(t));
marci@485: // typename ResGW::NodeMap<Num> a(res_graph);
marci@485: // typename ResGW::Node b;
marci@485: // Num j=a[b];
marci@485: // typename FilterResGW::NodeMap<Num> a1(filter_res_graph);
marci@485: // typename FilterResGW::Node b1;
marci@485: // Num j1=a1[b1];
marci@485: // typename ErasingResGW::NodeMap<Num> a2(erasing_res_graph);
marci@485: // typename ErasingResGW::Node b2;
marci@485: // Num j2=a2[b2];
marci@485: Num augment_value=free1[n];
marci@485: while (erasing_res_graph.valid(pred[n])) {
marci@485: typename ErasingResGW::OutEdgeIt e=pred[n];
marci@485: res_graph.augment(e, augment_value);
marci@485: n=erasing_res_graph.tail(e);
marci@485: if (res_graph.resCap(e)==0)
marci@485: erasing_res_graph.erase(e);
marci@478: }
marci@478: }
marci@478:
marci@485: } //while (__augment)
marci@478:
marci@485: return _augment;
marci@485: }
marci@478:
marci@478:
marci@478:
marci@478:
marci@478: } //namespace hugo
marci@478:
marci@480: #endif //HUGO_MAX_FLOW_H
marci@478:
marci@478:
marci@478:
marci@478: