jacint@109: // -*- C++ -*-
jacint@372: 
jacint@109: /*
jacint@109: Heuristics: 
jacint@109:  2 phase
jacint@109:  gap
jacint@109:  list 'level_list' on the nodes on level i implemented by hand
jacint@451:  stack 'active' on the active nodes on level i
jacint@109:  runs heuristic 'highest label' for H1*n relabels
jacint@113:  runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label'
jacint@109:  
jacint@451: Parameters H0 and H1 are initialized to 20 and 1.
jacint@109: 
jacint@211: Constructors:
jacint@109: 
jacint@372: Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if 
jacint@372:      FlowMap is not constant zero, and should be true if it is
jacint@109: 
jacint@109: Members:
jacint@109: 
jacint@211: void run()
jacint@109: 
marci@468: Num flowValue() : returns the value of a maximum flow
jacint@109: 
jacint@109: void minMinCut(CutMap& M) : sets M to the characteristic vector of the 
jacint@451:      minimum min cut. M should be a map of bools initialized to false. ??Is it OK?
jacint@109: 
jacint@109: void maxMinCut(CutMap& M) : sets M to the characteristic vector of the 
jacint@109:      maximum min cut. M should be a map of bools initialized to false.
jacint@109: 
jacint@109: void minCut(CutMap& M) : sets M to the characteristic vector of 
jacint@109:      a min cut. M should be a map of bools initialized to false.
jacint@109: 
jacint@109: */
jacint@109: 
jacint@211: #ifndef HUGO_PREFLOW_H
jacint@211: #define HUGO_PREFLOW_H
jacint@109: 
jacint@109: #define H0 20
jacint@109: #define H1 1
jacint@109: 
jacint@109: #include <vector>
jacint@109: #include <queue>
jacint@451: #include <stack>
jacint@109: 
marci@471: #include <graph_wrapper.h>
marci@472: #include <bfs_iterator.h>
marci@472: #include <invalid.h>
marci@472: #include <maps.h>
marci@472: #include <for_each_macros.h>
marci@472: 
marci@471: 
jacint@109: namespace hugo {
jacint@109: 
marci@468:   template <typename Graph, typename Num, 
marci@468: 	    typename CapMap=typename Graph::template EdgeMap<Num>, 
marci@468:             typename FlowMap=typename Graph::template EdgeMap<Num> >
jacint@211:   class Preflow {
jacint@109:     
jacint@211:     typedef typename Graph::Node Node;
jacint@109:     typedef typename Graph::NodeIt NodeIt;
jacint@109:     typedef typename Graph::OutEdgeIt OutEdgeIt;
jacint@109:     typedef typename Graph::InEdgeIt InEdgeIt;
jacint@451: 
jacint@451:     typedef typename std::vector<std::stack<Node> > VecStack;
jacint@451:     typedef typename Graph::template NodeMap<Node> NNMap;
jacint@451:     typedef typename std::vector<Node> VecNode;
jacint@451: 
marci@466:     const Graph* g;
jacint@211:     Node s;
jacint@211:     Node t;
marci@465:     const CapMap* capacity;  
jacint@451:     FlowMap* flow;
jacint@451:     int n;      //the number of nodes of G
marci@471:     typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW;
marci@471:     typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt;
marci@471:     typedef typename ResGW::Edge ResGWEdge;
marci@471:     //typedef typename ResGW::template NodeMap<bool> ReachedMap;
marci@471:     typedef typename Graph::template NodeMap<int> ReachedMap;
marci@471:     ReachedMap level;
marci@471:     //level works as a bool map in augmenting path algorithms 
marci@471:     //and is used by bfs for storing reached information.
marci@471:     //In preflow, it shows levels of nodes.
marci@471:     //typename Graph::template NodeMap<int> level;    
marci@468:     typename Graph::template NodeMap<Num> excess; 
jacint@451: 
jacint@109:   public:
jacint@451:  
jacint@451:     enum flowEnum{
jacint@451:       ZERO_FLOW=0,
jacint@451:       GEN_FLOW=1,
jacint@451:       PREFLOW=2
jacint@451:     };
jacint@451: 
marci@465:     Preflow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, 
jacint@451: 	    FlowMap& _flow) :
marci@466:       g(&_G), s(_s), t(_t), capacity(&_capacity), 
jacint@451:       flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0) {}
jacint@451: 
jacint@451:     void run() {
jacint@451:       preflow( ZERO_FLOW );
jacint@451:     }
jacint@372:     
jacint@451:     void preflow( flowEnum fe ) {
jacint@451:       preflowPhase0(fe);
jacint@451:       preflowPhase1();
jacint@451:     }
jacint@451: 
marci@471:     void preflowPhase0( flowEnum fe );
jacint@451: 
marci@471:     void preflowPhase1();
jacint@451: 
marci@471:     bool augmentOnShortestPath();
jacint@109: 
marci@471:     template<typename MutableGraph> bool augmentOnBlockingFlow();
jacint@451: 
marci@471:     bool augmentOnBlockingFlow2();
jacint@109: 
marci@472:     /// Returns the actual flow value.
marci@472:     /// More precisely, it returns the negative excess of s, thus 
marci@472:     /// this works also for preflows.
marci@472:     Num flowValue() { 
marci@472:       Num a=0;
marci@472:       FOR_EACH_INC_LOC(OutEdgeIt, e, *g, s) a+=(*flow)[e];
marci@472:       FOR_EACH_INC_LOC(InEdgeIt, e, *g, s) a-=(*flow)[e];
marci@472:       return a;
jacint@451:     }
jacint@109: 
jacint@451:     //should be used only between preflowPhase0 and preflowPhase1
jacint@451:     template<typename _CutMap>
jacint@451:     void actMinCut(_CutMap& M) {
jacint@211:       NodeIt v;
marci@466:       for(g->first(v); g->valid(v); g->next(v)) 
marci@466:       if ( level[v] < n ) {
marci@466: 	M.set(v,false);
marci@466:       } else {
marci@466: 	M.set(v,true);
marci@466:       }
jacint@211:     }
jacint@109: 
jacint@109: 
jacint@109: 
jacint@109:     /*
jacint@109:       Returns the minimum min cut, by a bfs from s in the residual graph.
jacint@109:     */
jacint@109:     template<typename _CutMap>
jacint@109:     void minMinCut(_CutMap& M) {
jacint@109:     
jacint@211:       std::queue<Node> queue;
jacint@109:       
jacint@109:       M.set(s,true);      
jacint@109:       queue.push(s);
jacint@109: 
jacint@109:       while (!queue.empty()) {
jacint@211:         Node w=queue.front();
jacint@109: 	queue.pop();
jacint@109: 
jacint@211: 	OutEdgeIt e;
marci@466: 	for(g->first(e,w) ; g->valid(e); g->next(e)) {
marci@466: 	  Node v=g->head(e);
jacint@451: 	  if (!M[v] && (*flow)[e] < (*capacity)[e] ) {
jacint@109: 	    queue.push(v);
jacint@109: 	    M.set(v, true);
jacint@109: 	  }
jacint@109: 	} 
jacint@109: 
jacint@211: 	InEdgeIt f;
marci@466: 	for(g->first(f,w) ; g->valid(f); g->next(f)) {
marci@466: 	  Node v=g->tail(f);
jacint@451: 	  if (!M[v] && (*flow)[f] > 0 ) {
jacint@109: 	    queue.push(v);
jacint@109: 	    M.set(v, true);
jacint@109: 	  }
jacint@109: 	} 
jacint@109:       }
jacint@109:     }
jacint@109: 
jacint@109: 
jacint@109:   
jacint@109:     /*
jacint@109:       Returns the maximum min cut, by a reverse bfs 
jacint@109:       from t in the residual graph.
jacint@109:     */
jacint@109:     
jacint@109:     template<typename _CutMap>
jacint@109:     void maxMinCut(_CutMap& M) {
jacint@451: 
jacint@451:       NodeIt v;
marci@466:       for(g->first(v) ; g->valid(v); g->next(v)) {
jacint@451: 	M.set(v, true);
jacint@451:       }
jacint@451: 
jacint@211:       std::queue<Node> queue;
jacint@109:       
jacint@451:       M.set(t,false);        
jacint@109:       queue.push(t);
jacint@109: 
jacint@109:       while (!queue.empty()) {
jacint@211:         Node w=queue.front();
jacint@109: 	queue.pop();
jacint@109: 
jacint@211: 
jacint@211: 	InEdgeIt e;
marci@466: 	for(g->first(e,w) ; g->valid(e); g->next(e)) {
marci@466: 	  Node v=g->tail(e);
jacint@451: 	  if (M[v] && (*flow)[e] < (*capacity)[e] ) {
jacint@109: 	    queue.push(v);
jacint@451: 	    M.set(v, false);
jacint@109: 	  }
jacint@109: 	}
jacint@211: 	
jacint@211: 	OutEdgeIt f;
marci@466: 	for(g->first(f,w) ; g->valid(f); g->next(f)) {
marci@466: 	  Node v=g->head(f);
jacint@451: 	  if (M[v] && (*flow)[f] > 0 ) {
jacint@109: 	    queue.push(v);
jacint@451: 	    M.set(v, false);
jacint@109: 	  }
jacint@109: 	}
jacint@109:       }
jacint@109:     }
jacint@109: 
jacint@109: 
jacint@109:     template<typename CutMap>
jacint@109:     void minCut(CutMap& M) {
jacint@109:       minMinCut(M);
jacint@109:     }
jacint@109: 
marci@468:     void resetTarget(Node _t) {t=_t;}
marci@468:     void resetSource(Node _s) {s=_s;}
jacint@372:    
marci@468:     void resetCap(const CapMap& _cap) {
jacint@451:       capacity=&_cap;
jacint@451:     }
jacint@451:     
marci@468:     void resetFlow(FlowMap& _flow) {
jacint@451:       flow=&_flow;
jacint@372:     }
jacint@372: 
jacint@372: 
jacint@451:   private:
jacint@451: 
marci@469:     int push(Node w, VecStack& active) {
jacint@451:       
jacint@451:       int lev=level[w];
marci@468:       Num exc=excess[w];
jacint@451:       int newlevel=n;       //bound on the next level of w
jacint@451: 	  
jacint@451:       OutEdgeIt e;
marci@466:       for(g->first(e,w); g->valid(e); g->next(e)) {
jacint@451: 	    
jacint@470: 	if ( (*flow)[e] >= (*capacity)[e] ) continue; 
marci@466: 	Node v=g->head(e);            
jacint@451: 	    
jacint@451: 	if( lev > level[v] ) { //Push is allowed now
jacint@451: 	  
jacint@470: 	  if ( excess[v]<=0 && v!=t && v!=s ) {
jacint@451: 	    int lev_v=level[v];
jacint@451: 	    active[lev_v].push(v);
jacint@451: 	  }
jacint@451: 	  
marci@468: 	  Num cap=(*capacity)[e];
marci@468: 	  Num flo=(*flow)[e];
marci@468: 	  Num remcap=cap-flo;
jacint@451: 	  
jacint@451: 	  if ( remcap >= exc ) { //A nonsaturating push.
jacint@451: 	    
jacint@451: 	    flow->set(e, flo+exc);
jacint@451: 	    excess.set(v, excess[v]+exc);
jacint@451: 	    exc=0;
jacint@451: 	    break; 
jacint@451: 	    
jacint@451: 	  } else { //A saturating push.
jacint@451: 	    flow->set(e, cap);
jacint@451: 	    excess.set(v, excess[v]+remcap);
jacint@451: 	    exc-=remcap;
jacint@451: 	  }
jacint@451: 	} else if ( newlevel > level[v] ) newlevel = level[v];
jacint@451:       } //for out edges wv 
jacint@451:       
jacint@451:       if ( exc > 0 ) {	
jacint@451: 	InEdgeIt e;
marci@466: 	for(g->first(e,w); g->valid(e); g->next(e)) {
jacint@451: 	  
jacint@470: 	  if( (*flow)[e] <= 0 ) continue; 
marci@466: 	  Node v=g->tail(e); 
jacint@451: 	  
jacint@451: 	  if( lev > level[v] ) { //Push is allowed now
jacint@451: 	    
jacint@470: 	    if ( excess[v]<=0 && v!=t && v!=s ) {
jacint@451: 	      int lev_v=level[v];
jacint@451: 	      active[lev_v].push(v);
jacint@451: 	    }
jacint@451: 	    
marci@468: 	    Num flo=(*flow)[e];
jacint@451: 	    
jacint@451: 	    if ( flo >= exc ) { //A nonsaturating push.
jacint@451: 	      
jacint@451: 	      flow->set(e, flo-exc);
jacint@451: 	      excess.set(v, excess[v]+exc);
jacint@451: 	      exc=0;
jacint@451: 	      break; 
jacint@451: 	    } else {  //A saturating push.
jacint@451: 	      
jacint@451: 	      excess.set(v, excess[v]+flo);
jacint@451: 	      exc-=flo;
jacint@451: 	      flow->set(e,0);
jacint@451: 	    }  
jacint@451: 	  } else if ( newlevel > level[v] ) newlevel = level[v];
jacint@451: 	} //for in edges vw
jacint@451: 	
jacint@451:       } // if w still has excess after the out edge for cycle
jacint@451:       
jacint@451:       excess.set(w, exc);
jacint@451:       
jacint@451:       return newlevel;
jacint@451:      }
jacint@451: 
jacint@451: 
jacint@451:     void preflowPreproc ( flowEnum fe, VecStack& active, 
jacint@451: 			  VecNode& level_list, NNMap& left, NNMap& right ) {
jacint@451: 
jacint@451:       std::queue<Node> bfs_queue;
jacint@451:       
jacint@451:       switch ( fe ) {
jacint@451:       case ZERO_FLOW: 
jacint@451: 	{
jacint@451: 	  //Reverse_bfs from t, to find the starting level.
jacint@451: 	  level.set(t,0);
jacint@451: 	  bfs_queue.push(t);
jacint@451: 	
jacint@451: 	  while (!bfs_queue.empty()) {
jacint@451: 	    
jacint@451: 	    Node v=bfs_queue.front();	
jacint@451: 	    bfs_queue.pop();
jacint@451: 	    int l=level[v]+1;
jacint@451: 	    
jacint@451: 	    InEdgeIt e;
marci@466: 	    for(g->first(e,v); g->valid(e); g->next(e)) {
marci@466: 	      Node w=g->tail(e);
jacint@451: 	      if ( level[w] == n && w != s ) {
jacint@451: 		bfs_queue.push(w);
jacint@451: 		Node first=level_list[l];
marci@466: 		if ( g->valid(first) ) left.set(first,w);
jacint@451: 		right.set(w,first);
jacint@451: 		level_list[l]=w;
jacint@451: 		level.set(w, l);
jacint@451: 	      }
jacint@451: 	    }
jacint@451: 	  }
jacint@451: 	  
jacint@451: 	  //the starting flow
jacint@451: 	  OutEdgeIt e;
marci@466: 	  for(g->first(e,s); g->valid(e); g->next(e)) 
jacint@451: 	    {
marci@468: 	      Num c=(*capacity)[e];
jacint@470: 	      if ( c <= 0 ) continue;
marci@466: 	      Node w=g->head(e);
jacint@451: 	      if ( level[w] < n ) {	  
jacint@470: 		if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
jacint@451: 		flow->set(e, c); 
jacint@451: 		excess.set(w, excess[w]+c);
jacint@451: 	      }
jacint@451: 	    }
jacint@451: 	  break;
jacint@451: 	}
jacint@451: 	
jacint@451:       case GEN_FLOW:
jacint@451:       case PREFLOW:
jacint@451: 	{
jacint@451: 	  //Reverse_bfs from t in the residual graph, 
jacint@451: 	  //to find the starting level.
jacint@451: 	  level.set(t,0);
jacint@451: 	  bfs_queue.push(t);
jacint@451: 	  
jacint@451: 	  while (!bfs_queue.empty()) {
jacint@451: 	    
jacint@451: 	    Node v=bfs_queue.front();	
jacint@451: 	    bfs_queue.pop();
jacint@451: 	    int l=level[v]+1;
jacint@451: 	    
jacint@451: 	    InEdgeIt e;
marci@466: 	    for(g->first(e,v); g->valid(e); g->next(e)) {
jacint@470: 	      if ( (*capacity)[e] <= (*flow)[e] ) continue;
marci@466: 	      Node w=g->tail(e);
jacint@451: 	      if ( level[w] == n && w != s ) {
jacint@451: 		bfs_queue.push(w);
jacint@451: 		Node first=level_list[l];
marci@466: 		if ( g->valid(first) ) left.set(first,w);
jacint@451: 		right.set(w,first);
jacint@451: 		level_list[l]=w;
jacint@451: 		level.set(w, l);
jacint@451: 	      }
jacint@451: 	    }
jacint@451: 	    
jacint@451: 	    OutEdgeIt f;
marci@466: 	    for(g->first(f,v); g->valid(f); g->next(f)) {
jacint@470: 	      if ( 0 >= (*flow)[f] ) continue;
marci@466: 	      Node w=g->head(f);
jacint@451: 	      if ( level[w] == n && w != s ) {
jacint@451: 		bfs_queue.push(w);
jacint@451: 		Node first=level_list[l];
marci@466: 		if ( g->valid(first) ) left.set(first,w);
jacint@451: 		right.set(w,first);
jacint@451: 		level_list[l]=w;
jacint@451: 		level.set(w, l);
jacint@451: 	      }
jacint@451: 	    }
jacint@451: 	  }
jacint@451: 	  
jacint@451: 	  
jacint@451: 	  //the starting flow
jacint@451: 	  OutEdgeIt e;
marci@466: 	  for(g->first(e,s); g->valid(e); g->next(e)) 
jacint@451: 	    {
marci@468: 	      Num rem=(*capacity)[e]-(*flow)[e];
jacint@470: 	      if ( rem <= 0 ) continue;
marci@466: 	      Node w=g->head(e);
jacint@451: 	      if ( level[w] < n ) {	  
jacint@470: 		if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
jacint@451: 		flow->set(e, (*capacity)[e]); 
jacint@451: 		excess.set(w, excess[w]+rem);
jacint@451: 	      }
jacint@451: 	    }
jacint@451: 	  
jacint@451: 	  InEdgeIt f;
marci@466: 	  for(g->first(f,s); g->valid(f); g->next(f)) 
jacint@451: 	    {
jacint@470: 	      if ( (*flow)[f] <= 0 ) continue;
marci@466: 	      Node w=g->tail(f);
jacint@451: 	      if ( level[w] < n ) {	  
jacint@470: 		if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w);
jacint@451: 		excess.set(w, excess[w]+(*flow)[f]);
jacint@451: 		flow->set(f, 0); 
jacint@451: 	      }
jacint@451: 	    }  
jacint@451: 	  break;
jacint@451: 	} //case PREFLOW
jacint@451:       }
jacint@451:     } //preflowPreproc
jacint@451: 
jacint@451: 
jacint@451: 
marci@469:     void relabel(Node w, int newlevel, VecStack& active,  
marci@469: 		 VecNode& level_list, NNMap& left, 
marci@472: 		 NNMap& right, int& b, int& k, bool what_heur ) 
marci@472:     {
jacint@451: 
marci@468:       Num lev=level[w];	
jacint@451:       
jacint@451:       Node right_n=right[w];
jacint@451:       Node left_n=left[w];
jacint@451:       
jacint@451:       //unlacing starts
marci@466:       if ( g->valid(right_n) ) {
marci@466: 	if ( g->valid(left_n) ) {
jacint@451: 	  right.set(left_n, right_n);
jacint@451: 	  left.set(right_n, left_n);
jacint@451: 	} else {
jacint@451: 	  level_list[lev]=right_n;   
jacint@451: 	  left.set(right_n, INVALID);
jacint@451: 	} 
jacint@451:       } else {
marci@466: 	if ( g->valid(left_n) ) {
jacint@451: 	  right.set(left_n, INVALID);
jacint@451: 	} else { 
jacint@451: 	  level_list[lev]=INVALID;   
jacint@451: 	} 
jacint@451:       } 
jacint@451:       //unlacing ends
jacint@451: 		
marci@466:       if ( !g->valid(level_list[lev]) ) {
jacint@451: 	      
jacint@451: 	//gapping starts
jacint@451: 	for (int i=lev; i!=k ; ) {
jacint@451: 	  Node v=level_list[++i];
marci@466: 	  while ( g->valid(v) ) {
jacint@451: 	    level.set(v,n);
jacint@451: 	    v=right[v];
jacint@451: 	  }
jacint@451: 	  level_list[i]=INVALID;
jacint@451: 	  if ( !what_heur ) {
jacint@451: 	    while ( !active[i].empty() ) {
jacint@451: 	      active[i].pop();    //FIXME: ezt szebben kene
jacint@451: 	    }
jacint@451: 	  }	     
jacint@451: 	}
jacint@451: 	
jacint@451: 	level.set(w,n);
jacint@451: 	b=lev-1;
jacint@451: 	k=b;
jacint@451: 	//gapping ends
jacint@451: 	
jacint@451:       } else {
jacint@451: 	
jacint@451: 	if ( newlevel == n ) level.set(w,n); 
jacint@451: 	else {
jacint@451: 	  level.set(w,++newlevel);
jacint@451: 	  active[newlevel].push(w);
jacint@451: 	  if ( what_heur ) b=newlevel;
jacint@451: 	  if ( k < newlevel ) ++k;      //now k=newlevel
jacint@451: 	  Node first=level_list[newlevel];
marci@466: 	  if ( g->valid(first) ) left.set(first,w);
jacint@451: 	  right.set(w,first);
jacint@451: 	  left.set(w,INVALID);
jacint@451: 	  level_list[newlevel]=w;
jacint@451: 	}
jacint@451:       }
jacint@451:       
jacint@451:     } //relabel
marci@472: 
marci@472: 
marci@472:     template<typename MapGraphWrapper> 
marci@472:     class DistanceMap {
marci@472:     protected:
marci@472:       const MapGraphWrapper* g;
marci@472:       typename MapGraphWrapper::template NodeMap<int> dist; 
marci@472:     public:
marci@472:       DistanceMap(MapGraphWrapper& _g) : g(&_g), dist(*g, g->nodeNum()) { }
marci@472:       void set(const typename MapGraphWrapper::Node& n, int a) { 
marci@472: 	dist.set(n, a); 
marci@472:       }
marci@472:       int operator[](const typename MapGraphWrapper::Node& n) 
marci@472: 	{ return dist[n]; }
marci@472: //       int get(const typename MapGraphWrapper::Node& n) const { 
marci@472: // 	return dist[n]; }
marci@472: //       bool get(const typename MapGraphWrapper::Edge& e) const { 
marci@472: // 	return (dist.get(g->tail(e))<dist.get(g->head(e))); }
marci@472:       bool operator[](const typename MapGraphWrapper::Edge& e) const { 
marci@472: 	return (dist[g->tail(e)]<dist[g->head(e)]); 
marci@472:       }
marci@472:     };
jacint@451:     
marci@471:   };
jacint@109: 
marci@471: 
marci@471:   template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@471:   void Preflow<Graph, Num, CapMap, FlowMap>::preflowPhase0( flowEnum fe ) 
marci@471:   {
marci@471:       
marci@471:       int heur0=(int)(H0*n);  //time while running 'bound decrease' 
marci@471:       int heur1=(int)(H1*n);  //time while running 'highest label'
marci@471:       int heur=heur1;         //starting time interval (#of relabels)
marci@471:       int numrelabel=0;
marci@471:      
marci@471:       bool what_heur=1;       
marci@471:       //It is 0 in case 'bound decrease' and 1 in case 'highest label'
marci@471: 
marci@471:       bool end=false;     
marci@471:       //Needed for 'bound decrease', true means no active nodes are above bound b.
marci@471: 
marci@471:       int k=n-2;  //bound on the highest level under n containing a node
marci@471:       int b=k;    //bound on the highest level under n of an active node
marci@471:       
marci@471:       VecStack active(n);
marci@471:       
marci@471:       NNMap left(*g, INVALID);
marci@471:       NNMap right(*g, INVALID);
marci@471:       VecNode level_list(n,INVALID);
marci@471:       //List of the nodes in level i<n, set to n.
marci@471: 
marci@471:       NodeIt v;
marci@471:       for(g->first(v); g->valid(v); g->next(v)) level.set(v,n);
marci@471:       //setting each node to level n
marci@471:       
marci@471:       switch ( fe ) {
marci@471:       case PREFLOW:
marci@471: 	{
marci@471: 	  //counting the excess
marci@471: 	  NodeIt v;
marci@471: 	  for(g->first(v); g->valid(v); g->next(v)) {
marci@471: 	    Num exc=0;
marci@471: 	  
marci@471: 	    InEdgeIt e;
marci@471: 	    for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e];
marci@471: 	    OutEdgeIt f;
marci@471: 	    for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f];
marci@471: 	    
marci@471: 	    excess.set(v,exc);	  
marci@471: 	    
marci@471: 	    //putting the active nodes into the stack
marci@471: 	    int lev=level[v];
marci@471: 	    if ( exc > 0 && lev < n && v != t ) active[lev].push(v);
marci@471: 	  }
marci@471: 	  break;
marci@471: 	}
marci@471:       case GEN_FLOW:
marci@471: 	{
marci@471: 	  //Counting the excess of t
marci@471: 	  Num exc=0;
marci@471: 	  
marci@471: 	  InEdgeIt e;
marci@471: 	  for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e];
marci@471: 	  OutEdgeIt f;
marci@471: 	  for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f];
marci@471: 	  
marci@471: 	  excess.set(t,exc);	
marci@471: 	  
marci@471: 	  break;
marci@471: 	}
marci@471:       default:
marci@471: 	break;
marci@471:       }
marci@471:       
marci@471:       preflowPreproc( fe, active, level_list, left, right );
marci@471:       //End of preprocessing 
marci@471:       
marci@471:       
marci@471:       //Push/relabel on the highest level active nodes.
marci@471:       while ( true ) {
marci@471: 	if ( b == 0 ) {
marci@471: 	  if ( !what_heur && !end && k > 0 ) {
marci@471: 	    b=k;
marci@471: 	    end=true;
marci@471: 	  } else break;
marci@471: 	}
marci@471: 	
marci@471: 	if ( active[b].empty() ) --b; 
marci@471: 	else {
marci@471: 	  end=false;  
marci@471: 	  Node w=active[b].top();
marci@471: 	  active[b].pop();
marci@471: 	  int newlevel=push(w,active);
marci@471: 	  if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list, 
marci@471: 				       left, right, b, k, what_heur);
marci@471: 	  
marci@471: 	  ++numrelabel; 
marci@471: 	  if ( numrelabel >= heur ) {
marci@471: 	    numrelabel=0;
marci@471: 	    if ( what_heur ) {
marci@471: 	      what_heur=0;
marci@471: 	      heur=heur0;
marci@471: 	      end=false;
marci@471: 	    } else {
marci@471: 	      what_heur=1;
marci@471: 	      heur=heur1;
marci@471: 	      b=k; 
marci@471: 	    }
marci@471: 	  }
marci@471: 	} 
marci@471:       } 
marci@471:     }
marci@471: 
marci@471: 
marci@471: 
marci@471:   template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@471:   void Preflow<Graph, Num, CapMap, FlowMap>::preflowPhase1() 
marci@471:   {
marci@471:       
marci@471:       int k=n-2;  //bound on the highest level under n containing a node
marci@471:       int b=k;    //bound on the highest level under n of an active node
marci@471:       
marci@471:       VecStack active(n);
marci@471:       level.set(s,0);
marci@471:       std::queue<Node> bfs_queue;
marci@471:       bfs_queue.push(s);
marci@471: 	    
marci@471:       while (!bfs_queue.empty()) {
marci@471: 	
marci@471: 	Node v=bfs_queue.front();	
marci@471: 	bfs_queue.pop();
marci@471: 	int l=level[v]+1;
marci@471: 	      
marci@471: 	InEdgeIt e;
marci@471: 	for(g->first(e,v); g->valid(e); g->next(e)) {
marci@471: 	  if ( (*capacity)[e] <= (*flow)[e] ) continue;
marci@471: 	  Node u=g->tail(e);
marci@471: 	  if ( level[u] >= n ) { 
marci@471: 	    bfs_queue.push(u);
marci@471: 	    level.set(u, l);
marci@471: 	    if ( excess[u] > 0 ) active[l].push(u);
marci@471: 	  }
marci@471: 	}
marci@471: 	
marci@471: 	OutEdgeIt f;
marci@471: 	for(g->first(f,v); g->valid(f); g->next(f)) {
marci@471: 	  if ( 0 >= (*flow)[f] ) continue;
marci@471: 	  Node u=g->head(f);
marci@471: 	  if ( level[u] >= n ) { 
marci@471: 	    bfs_queue.push(u);
marci@471: 	    level.set(u, l);
marci@471: 	    if ( excess[u] > 0 ) active[l].push(u);
marci@471: 	  }
marci@471: 	}
marci@471:       }
marci@471:       b=n-2;
marci@471: 
marci@471:       while ( true ) {
marci@471: 	
marci@471: 	if ( b == 0 ) break;
marci@471: 
marci@471: 	if ( active[b].empty() ) --b; 
marci@471: 	else {
marci@471: 	  Node w=active[b].top();
marci@471: 	  active[b].pop();
marci@471: 	  int newlevel=push(w,active);	  
marci@471: 
marci@471: 	  //relabel
marci@471: 	  if ( excess[w] > 0 ) {
marci@471: 	    level.set(w,++newlevel);
marci@471: 	    active[newlevel].push(w);
marci@471: 	    b=newlevel;
marci@471: 	  }
marci@471: 	}  // if stack[b] is nonempty
marci@471:       } // while(true)
marci@471:     }
marci@471: 
marci@471: 
marci@471: 
marci@472:   template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@472:   bool Preflow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath() 
marci@472:   {
marci@472:       ResGW res_graph(*g, *capacity, *flow);
marci@472:       bool _augment=false;
marci@472:       
marci@472:       //ReachedMap level(res_graph);
marci@472:       FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@472:       BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@472:       bfs.pushAndSetReached(s);
marci@472: 	
marci@472:       typename ResGW::template NodeMap<ResGWEdge> pred(res_graph); 
marci@472:       pred.set(s, INVALID);
marci@472:       
marci@472:       typename ResGW::template NodeMap<Num> free(res_graph);
marci@472: 	
marci@472:       //searching for augmenting path
marci@472:       while ( !bfs.finished() ) { 
marci@472: 	ResGWOutEdgeIt e=bfs;
marci@472: 	if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
marci@472: 	  Node v=res_graph.tail(e);
marci@472: 	  Node w=res_graph.head(e);
marci@472: 	  pred.set(w, e);
marci@472: 	  if (res_graph.valid(pred[v])) {
marci@472: 	    free.set(w, std::min(free[v], res_graph.resCap(e)));
marci@472: 	  } else {
marci@472: 	    free.set(w, res_graph.resCap(e)); 
marci@472: 	  }
marci@472: 	  if (res_graph.head(e)==t) { _augment=true; break; }
marci@472: 	}
marci@472: 	
marci@472: 	++bfs;
marci@472:       } //end of searching augmenting path
marci@471: 
marci@472:       if (_augment) {
marci@472: 	Node n=t;
marci@472: 	Num augment_value=free[t];
marci@472: 	while (res_graph.valid(pred[n])) { 
marci@472: 	  ResGWEdge e=pred[n];
marci@472: 	  res_graph.augment(e, augment_value); 
marci@472: 	  n=res_graph.tail(e);
marci@472: 	}
marci@472:       }
marci@471: 
marci@472:       return _augment;
marci@472:     }
marci@471: 
marci@471: 
marci@471: 
marci@471: 
marci@471: 
marci@471: 
jacint@109: 
marci@472: 
marci@472: 
marci@472:   template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@472:   template<typename MutableGraph> 
marci@472:   bool Preflow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow() 
marci@472:   {      
marci@472:       typedef MutableGraph MG;
marci@472:       bool _augment=false;
marci@472: 
marci@472:       ResGW res_graph(*g, *capacity, *flow);
marci@472: 
marci@472:       //bfs for distances on the residual graph
marci@472:       //ReachedMap level(res_graph);
marci@472:       FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@472:       BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@472:       bfs.pushAndSetReached(s);
marci@472:       typename ResGW::template NodeMap<int> 
marci@472: 	dist(res_graph); //filled up with 0's
marci@472: 
marci@472:       //F will contain the physical copy of the residual graph
marci@472:       //with the set of edges which are on shortest paths
marci@472:       MG F;
marci@472:       typename ResGW::template NodeMap<typename MG::Node> 
marci@472: 	res_graph_to_F(res_graph);
marci@472:       {
marci@472: 	typename ResGW::NodeIt n;
marci@472: 	for(res_graph.first(n); res_graph.valid(n); res_graph.next(n)) {
marci@472: 	  res_graph_to_F.set(n, F.addNode());
marci@472: 	}
marci@472:       }
marci@472: 
marci@472:       typename MG::Node sF=res_graph_to_F[s];
marci@472:       typename MG::Node tF=res_graph_to_F[t];
marci@472:       typename MG::template EdgeMap<ResGWEdge> original_edge(F);
marci@472:       typename MG::template EdgeMap<Num> residual_capacity(F);
marci@472: 
marci@472:       while ( !bfs.finished() ) { 
marci@472: 	ResGWOutEdgeIt e=bfs;
marci@472: 	if (res_graph.valid(e)) {
marci@472: 	  if (bfs.isBNodeNewlyReached()) {
marci@472: 	    dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1);
marci@472: 	    typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]);
marci@472: 	    original_edge.update();
marci@472: 	    original_edge.set(f, e);
marci@472: 	    residual_capacity.update();
marci@472: 	    residual_capacity.set(f, res_graph.resCap(e));
marci@472: 	  } else {
marci@472: 	    if (dist[res_graph.head(e)]==(dist[res_graph.tail(e)]+1)) {
marci@472: 	      typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]);
marci@472: 	      original_edge.update();
marci@472: 	      original_edge.set(f, e);
marci@472: 	      residual_capacity.update();
marci@472: 	      residual_capacity.set(f, res_graph.resCap(e));
marci@472: 	    }
marci@472: 	  }
marci@472: 	}
marci@472: 	++bfs;
marci@472:       } //computing distances from s in the residual graph
marci@472: 
marci@472:       bool __augment=true;
marci@472: 
marci@472:       while (__augment) {
marci@472: 	__augment=false;
marci@472: 	//computing blocking flow with dfs
marci@472: 	DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F);
marci@472: 	typename MG::template NodeMap<typename MG::Edge> pred(F);
marci@472: 	pred.set(sF, INVALID);
marci@472: 	//invalid iterators for sources
marci@472: 
marci@472: 	typename MG::template NodeMap<Num> free(F);
marci@472: 
marci@472: 	dfs.pushAndSetReached(sF);      
marci@472: 	while (!dfs.finished()) {
marci@472: 	  ++dfs;
marci@472: 	  if (F.valid(/*typename MG::OutEdgeIt*/(dfs))) {
marci@472: 	    if (dfs.isBNodeNewlyReached()) {
marci@472: 	      typename MG::Node v=F.aNode(dfs);
marci@472: 	      typename MG::Node w=F.bNode(dfs);
marci@472: 	      pred.set(w, dfs);
marci@472: 	      if (F.valid(pred[v])) {
marci@472: 		free.set(w, std::min(free[v], residual_capacity[dfs]));
marci@472: 	      } else {
marci@472: 		free.set(w, residual_capacity[dfs]); 
marci@472: 	      }
marci@472: 	      if (w==tF) { 
marci@472: 		__augment=true; 
marci@472: 		_augment=true;
marci@472: 		break; 
marci@472: 	      }
marci@472: 	      
marci@472: 	    } else {
marci@472: 	      F.erase(/*typename MG::OutEdgeIt*/(dfs));
marci@472: 	    }
marci@472: 	  } 
marci@472: 	}
marci@472: 
marci@472: 	if (__augment) {
marci@472: 	  typename MG::Node n=tF;
marci@472: 	  Num augment_value=free[tF];
marci@472: 	  while (F.valid(pred[n])) { 
marci@472: 	    typename MG::Edge e=pred[n];
marci@472: 	    res_graph.augment(original_edge[e], augment_value); 
marci@472: 	    n=F.tail(e);
marci@472: 	    if (residual_capacity[e]==augment_value) 
marci@472: 	      F.erase(e); 
marci@472: 	    else 
marci@472: 	      residual_capacity.set(e, residual_capacity[e]-augment_value);
marci@472: 	  }
marci@472: 	}
marci@472: 	
marci@472:       }
marci@472:             
marci@472:       return _augment;
marci@472:     }
marci@472: 
marci@472: 
marci@472: 
marci@472: 
marci@472: 
marci@472: 
marci@472:   template <typename Graph, typename Num, typename CapMap, typename FlowMap>
marci@472:   bool Preflow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2() 
marci@472:   {
marci@472:       bool _augment=false;
marci@472: 
marci@472:       ResGW res_graph(*g, *capacity, *flow);
marci@472:       
marci@472:       //ReachedMap level(res_graph);
marci@472:       FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0);
marci@472:       BfsIterator<ResGW, ReachedMap> bfs(res_graph, level);
marci@472: 
marci@472:       bfs.pushAndSetReached(s);
marci@472:       DistanceMap<ResGW> dist(res_graph);
marci@472:       while ( !bfs.finished() ) { 
marci@472:  	ResGWOutEdgeIt e=bfs;
marci@472:  	if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) {
marci@472:  	  dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1);
marci@472:  	}
marci@472: 	++bfs;
marci@472:       } //computing distances from s in the residual graph
marci@472: 
marci@472:       //Subgraph containing the edges on some shortest paths
marci@472:       ConstMap<typename ResGW::Node, bool> true_map(true);
marci@472:       typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>, 
marci@472: 	DistanceMap<ResGW> > FilterResGW;
marci@472:       FilterResGW filter_res_graph(res_graph, true_map, dist);
marci@472: 
marci@472:       //Subgraph, which is able to delete edges which are already 
marci@472:       //met by the dfs
marci@472:       typename FilterResGW::template NodeMap<typename FilterResGW::OutEdgeIt> 
marci@472:  	first_out_edges(filter_res_graph);
marci@472:       typename FilterResGW::NodeIt v;
marci@472:       for(filter_res_graph.first(v); filter_res_graph.valid(v); 
marci@472:  	  filter_res_graph.next(v)) 
marci@472:       {
marci@472:  	typename FilterResGW::OutEdgeIt e;
marci@472:  	filter_res_graph.first(e, v);
marci@472:  	first_out_edges.set(v, e);
marci@472:       }
marci@472:       typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW::
marci@472: 	template NodeMap<typename FilterResGW::OutEdgeIt> > ErasingResGW;
marci@472:       ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges);
marci@472: 
marci@472:       bool __augment=true;
marci@472: 
marci@472:       while (__augment) {
marci@472: 
marci@472:  	__augment=false;
marci@472:   	//computing blocking flow with dfs
marci@472:   	DfsIterator< ErasingResGW, 
marci@472: 	  typename ErasingResGW::template NodeMap<bool> > 
marci@472:   	  dfs(erasing_res_graph);
marci@472:  	typename ErasingResGW::
marci@472: 	  template NodeMap<typename ErasingResGW::OutEdgeIt> 
marci@472: 	  pred(erasing_res_graph); 
marci@472:  	pred.set(s, INVALID);
marci@472:   	//invalid iterators for sources
marci@472: 
marci@472:   	typename ErasingResGW::template NodeMap<Num> 
marci@472: 	  free1(erasing_res_graph);
marci@472: 
marci@472:  	dfs.pushAndSetReached(
marci@472: 	  typename ErasingResGW::Node(
marci@472: 	    typename FilterResGW::Node(
marci@472: 	      typename ResGW::Node(s)
marci@472: 	      )
marci@472: 	    )
marci@472: 	  );
marci@472:  	while (!dfs.finished()) {
marci@472:  	  ++dfs;
marci@472:  	  if (erasing_res_graph.valid(
marci@472:  		typename ErasingResGW::OutEdgeIt(dfs))) 
marci@472:  	  { 
marci@472:   	    if (dfs.isBNodeNewlyReached()) {
marci@472: 	  
marci@472:  	      typename ErasingResGW::Node v=erasing_res_graph.aNode(dfs);
marci@472:  	      typename ErasingResGW::Node w=erasing_res_graph.bNode(dfs);
marci@472: 
marci@472:  	      pred.set(w, /*typename ErasingResGW::OutEdgeIt*/(dfs));
marci@472:  	      if (erasing_res_graph.valid(pred[v])) {
marci@472:  		free1.set(w, std::min(free1[v], res_graph.resCap(
marci@472: 				       typename ErasingResGW::OutEdgeIt(dfs))));
marci@472:  	      } else {
marci@472:  		free1.set(w, res_graph.resCap(
marci@472: 			   typename ErasingResGW::OutEdgeIt(dfs))); 
marci@472:  	      }
marci@472: 	      
marci@472:  	      if (w==t) { 
marci@472:  		__augment=true; 
marci@472:  		_augment=true;
marci@472:  		break; 
marci@472:  	      }
marci@472:  	    } else {
marci@472:  	      erasing_res_graph.erase(dfs);
marci@472: 	    }
marci@472: 	  }
marci@472: 	}	
marci@472: 
marci@472:   	if (__augment) {
marci@472:    	  typename ErasingResGW::Node n=typename FilterResGW::Node(typename ResGW::Node(t));
marci@472: // 	  typename ResGW::NodeMap<Num> a(res_graph);
marci@472: // 	  typename ResGW::Node b;
marci@472: // 	  Num j=a[b];
marci@472: // 	  typename FilterResGW::NodeMap<Num> a1(filter_res_graph);
marci@472: // 	  typename FilterResGW::Node b1;
marci@472: // 	  Num j1=a1[b1];
marci@472: // 	  typename ErasingResGW::NodeMap<Num> a2(erasing_res_graph);
marci@472: // 	  typename ErasingResGW::Node b2;
marci@472: // 	  Num j2=a2[b2];
marci@472:  	  Num augment_value=free1[n];
marci@472:  	  while (erasing_res_graph.valid(pred[n])) { 
marci@472:  	    typename ErasingResGW::OutEdgeIt e=pred[n];
marci@472:  	    res_graph.augment(e, augment_value);
marci@472:  	    n=erasing_res_graph.tail(e);
marci@472:  	    if (res_graph.resCap(e)==0)
marci@472:  	      erasing_res_graph.erase(e);
marci@472: 	}
marci@472:       }
marci@472:       
marci@472:       } //while (__augment) 
marci@472:             
marci@472:       return _augment;
marci@472:     }
marci@472: 
marci@472: 
marci@472: 
marci@472: 
marci@174: } //namespace hugo
jacint@109: 
jacint@451: #endif //HUGO_PREFLOW_H
jacint@109: 
jacint@109: 
marci@174: 
marci@174: