[Lemon-commits] [lemon_svn] jacint: r499 - hugo/trunk/src/work/jacint
Lemon SVN
svn at lemon.cs.elte.hu
Mon Nov 6 20:39:46 CET 2006
Author: jacint
Date: Thu Apr 22 15:51:25 2004
New Revision: 499
Added:
hugo/trunk/src/work/jacint/preflowproba.h
Log:
Added: hugo/trunk/src/work/jacint/preflowproba.h
==============================================================================
--- (empty file)
+++ hugo/trunk/src/work/jacint/preflowproba.h Thu Apr 22 15:51:25 2004
@@ -0,0 +1,685 @@
+// -*- C++ -*-
+
+//run gyorsan tudna adni a minmincutot a 2 fazis elejen , ne vegyuk be konstruktorba egy cutmapet?
+//constzero jo igy?
+
+//majd marci megmondja betegyem-e bfs-t meg resgraphot
+
+/*
+Heuristics:
+ 2 phase
+ gap
+ list 'level_list' on the nodes on level i implemented by hand
+ stack 'active' on the active nodes on level i implemented by hand
+ runs heuristic 'highest label' for H1*n relabels
+ runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label'
+
+Parameters H0 and H1 are initialized to 20 and 10.
+
+Constructors:
+
+Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if
+ FlowMap is not constant zero, and should be true if it is
+
+Members:
+
+void run()
+
+T flowValue() : returns the value of a maximum flow
+
+void minMinCut(CutMap& M) : sets M to the characteristic vector of the
+ minimum min cut. M should be a map of bools initialized to false.
+
+void maxMinCut(CutMap& M) : sets M to the characteristic vector of the
+ maximum min cut. M should be a map of bools initialized to false.
+
+void minCut(CutMap& M) : sets M to the characteristic vector of
+ a min cut. M should be a map of bools initialized to false.
+
+FIXME reset
+
+*/
+
+#ifndef HUGO_PREFLOW_H
+#define HUGO_PREFLOW_H
+
+#define H0 20
+#define H1 1
+
+#include <vector>
+#include <queue>
+#include<graph_wrapper.h>
+
+namespace hugo {
+
+ template <typename Graph, typename T,
+ typename CapMap=typename Graph::EdgeMap<T>,
+ typename FlowMap=typename Graph::EdgeMap<T> >
+ class Preflow {
+
+ typedef typename Graph::Node Node;
+ typedef typename Graph::Edge Edge;
+ typedef typename Graph::NodeIt NodeIt;
+ typedef typename Graph::OutEdgeIt OutEdgeIt;
+ typedef typename Graph::InEdgeIt InEdgeIt;
+
+ const Graph& G;
+ Node s;
+ Node t;
+ const CapMap& capacity;
+ FlowMap& flow;
+ T value;
+ bool constzero;
+
+ typedef ResGraphWrapper<const Graph, T, CapMap, FlowMap> ResGW;
+ typedef typename ResGW::OutEdgeIt ResOutEdgeIt;
+ typedef typename ResGW::InEdgeIt ResInEdgeIt;
+ typedef typename ResGW::Edge ResEdge;
+
+ public:
+ Preflow(Graph& _G, Node _s, Node _t, CapMap& _capacity,
+ FlowMap& _flow, bool _constzero ) :
+ G(_G), s(_s), t(_t), capacity(_capacity), flow(_flow), constzero(_constzero) {}
+
+
+ void run() {
+
+ ResGW res_graph(G, capacity, flow);
+
+ value=0; //for the subsequent runs
+
+ bool phase=0; //phase 0 is the 1st phase, phase 1 is the 2nd
+ int n=G.nodeNum();
+ int heur0=(int)(H0*n); //time while running 'bound decrease'
+ int heur1=(int)(H1*n); //time while running 'highest label'
+ int heur=heur1; //starting time interval (#of relabels)
+ bool what_heur=1;
+ /*
+ what_heur is 0 in case 'bound decrease'
+ and 1 in case 'highest label'
+ */
+ bool end=false;
+ /*
+ Needed for 'bound decrease', 'true'
+ means no active nodes are above bound b.
+ */
+ int relabel=0;
+ int k=n-2; //bound on the highest level under n containing a node
+ int b=k; //bound on the highest level under n of an active node
+
+ typename Graph::NodeMap<int> level(G,n);
+ typename Graph::NodeMap<T> excess(G);
+
+ std::vector<Node> active(n-1,INVALID);
+ typename Graph::NodeMap<Node> next(G,INVALID);
+ //Stack of the active nodes in level i < n.
+ //We use it in both phases.
+
+ typename Graph::NodeMap<Node> left(G,INVALID);
+ typename Graph::NodeMap<Node> right(G,INVALID);
+ std::vector<Node> level_list(n,INVALID);
+ /*
+ List of the nodes in level i<n.
+ */
+
+
+ if ( constzero ) {
+
+ /*Reverse_bfs from t, to find the starting level.*/
+ level.set(t,0);
+ std::queue<Node> bfs_queue;
+ bfs_queue.push(t);
+
+ while (!bfs_queue.empty()) {
+
+ Node v=bfs_queue.front();
+ bfs_queue.pop();
+ int l=level[v]+1;
+
+ InEdgeIt e;
+ for(G.first(e,v); G.valid(e); G.next(e)) {
+ Node w=G.tail(e);
+ if ( level[w] == n && w != s ) {
+ bfs_queue.push(w);
+ Node first=level_list[l];
+ if ( G.valid(first) ) left.set(first,w);
+ right.set(w,first);
+ level_list[l]=w;
+ level.set(w, l);
+ }
+ }
+ }
+
+ //the starting flow
+ OutEdgeIt e;
+ for(G.first(e,s); G.valid(e); G.next(e))
+ {
+ T c=capacity[e];
+ if ( c == 0 ) continue;
+ Node w=G.head(e);
+ if ( level[w] < n ) {
+ if ( excess[w] == 0 && w!=t ) {
+ next.set(w,active[level[w]]);
+ active[level[w]]=w;
+ }
+ flow.set(e, c);
+ excess.set(w, excess[w]+c);
+ }
+ }
+ }
+ else
+ {
+
+ /*
+ Reverse_bfs from t in the residual graph,
+ to find the starting level.
+ */
+ level.set(t,0);
+ std::queue<Node> bfs_queue;
+ bfs_queue.push(t);
+
+ while (!bfs_queue.empty()) {
+
+ Node v=bfs_queue.front();
+ bfs_queue.pop();
+ int l=level[v]+1;
+
+ InEdgeIt e;
+ for(G.first(e,v); G.valid(e); G.next(e)) {
+ if ( capacity[e] == flow[e] ) continue;
+ Node w=G.tail(e);
+ if ( level[w] == n && w != s ) {
+ bfs_queue.push(w);
+ Node first=level_list[l];
+ if ( G.valid(first) ) left.set(first,w);
+ right.set(w,first);
+ level_list[l]=w;
+ level.set(w, l);
+ }
+ }
+
+ OutEdgeIt f;
+ for(G.first(f,v); G.valid(f); G.next(f)) {
+ if ( 0 == flow[f] ) continue;
+ Node w=G.head(f);
+ if ( level[w] == n && w != s ) {
+ bfs_queue.push(w);
+ Node first=level_list[l];
+ if ( G.valid(first) ) left.set(first,w);
+ right.set(w,first);
+ level_list[l]=w;
+ level.set(w, l);
+ }
+ }
+ }
+
+
+ /*
+ Counting the excess
+ */
+ NodeIt v;
+ for(G.first(v); G.valid(v); G.next(v)) {
+ T exc=0;
+
+ InEdgeIt e;
+ for(G.first(e,v); G.valid(e); G.next(e)) exc+=flow[e];
+ OutEdgeIt f;
+ for(G.first(f,v); G.valid(f); G.next(f)) exc-=flow[e];
+
+ excess.set(v,exc);
+
+ //putting the active nodes into the stack
+ int lev=level[v];
+ if ( exc > 0 && lev < n ) {
+ next.set(v,active[lev]);
+ active[lev]=v;
+ }
+ }
+
+
+ //the starting flow
+ OutEdgeIt e;
+ for(G.first(e,s); G.valid(e); G.next(e))
+ {
+ T rem=capacity[e]-flow[e];
+ if ( rem == 0 ) continue;
+ Node w=G.head(e);
+ if ( level[w] < n ) {
+ if ( excess[w] == 0 && w!=t ) {
+ next.set(w,active[level[w]]);
+ active[level[w]]=w;
+ }
+ flow.set(e, capacity[e]);
+ excess.set(w, excess[w]+rem);
+ }
+ }
+
+ InEdgeIt f;
+ for(G.first(f,s); G.valid(f); G.next(f))
+ {
+ if ( flow[f] == 0 ) continue;
+ Node w=G.head(f);
+ if ( level[w] < n ) {
+ if ( excess[w] == 0 && w!=t ) {
+ next.set(w,active[level[w]]);
+ active[level[w]]=w;
+ }
+ excess.set(w, excess[w]+flow[f]);
+ flow.set(f, 0);
+ }
+ }
+ }
+
+
+
+
+ /*
+ End of preprocessing
+ */
+
+
+
+ /*
+ Push/relabel on the highest level active nodes.
+ */
+ while ( true ) {
+
+ if ( b == 0 ) {
+ if ( phase ) break;
+
+ if ( !what_heur && !end && k > 0 ) {
+ b=k;
+ end=true;
+ } else {
+ phase=1;
+ level.set(s,0);
+ std::queue<Node> bfs_queue;
+ bfs_queue.push(s);
+
+ while (!bfs_queue.empty()) {
+
+ Node v=bfs_queue.front();
+ bfs_queue.pop();
+ int l=level[v]+1;
+
+ ResInEdgeIt e;
+ for(res_graph.first(e,s); res_graph.valid(e);
+ res_graph.next(e)) {
+ Node u=res_graph.tail(e);
+ if ( level[u] >= n ) {
+ bfs_queue.push(u);
+ level.set(u, l);
+ if ( excess[u] > 0 ) {
+ next.set(u,active[l]);
+ active[l]=u;
+ }
+ }
+ }
+ /* InEdgeIt e;
+ for(G.first(e,v); G.valid(e); G.next(e)) {
+ if ( capacity[e] == flow[e] ) continue;
+ Node u=G.tail(e);
+ if ( level[u] >= n ) {
+ bfs_queue.push(u);
+ level.set(u, l);
+ if ( excess[u] > 0 ) {
+ next.set(u,active[l]);
+ active[l]=u;
+ }
+ }
+ }
+
+ OutEdgeIt f;
+ for(G.first(f,v); G.valid(f); G.next(f)) {
+ if ( 0 == flow[f] ) continue;
+ Node u=G.head(f);
+ if ( level[u] >= n ) {
+ bfs_queue.push(u);
+ level.set(u, l);
+ if ( excess[u] > 0 ) {
+ next.set(u,active[l]);
+ active[l]=u;
+ }
+ }
+ }*/
+ }
+ b=n-2;
+ }
+
+ }
+
+
+ if ( !G.valid(active[b]) ) --b;
+ else {
+ end=false;
+
+ Node w=active[b];
+ active[b]=next[w];
+ int lev=level[w];
+ T exc=excess[w];
+ int newlevel=n; //bound on the next level of w
+
+ OutEdgeIt e;
+ for(G.first(e,w); G.valid(e); G.next(e)) {
+
+ if ( flow[e] == capacity[e] ) continue;
+ Node v=G.head(e);
+ //e=wv
+
+ if( lev > level[v] ) {
+ /*Push is allowed now*/
+
+ if ( excess[v]==0 && v!=t && v!=s ) {
+ int lev_v=level[v];
+ next.set(v,active[lev_v]);
+ active[lev_v]=v;
+ }
+
+ T cap=capacity[e];
+ T flo=flow[e];
+ T remcap=cap-flo;
+
+ if ( remcap >= exc ) {
+ /*A nonsaturating push.*/
+
+ flow.set(e, flo+exc);
+ excess.set(v, excess[v]+exc);
+ exc=0;
+ break;
+
+ } else {
+ /*A saturating push.*/
+
+ flow.set(e, cap);
+ excess.set(v, excess[v]+remcap);
+ exc-=remcap;
+ }
+ } else if ( newlevel > level[v] ){
+ newlevel = level[v];
+ }
+
+ } //for out edges wv
+
+
+ if ( exc > 0 ) {
+ InEdgeIt e;
+ for(G.first(e,w); G.valid(e); G.next(e)) {
+
+ if( flow[e] == 0 ) continue;
+ Node v=G.tail(e);
+ //e=vw
+
+ if( lev > level[v] ) {
+ /*Push is allowed now*/
+
+ if ( excess[v]==0 && v!=t && v!=s ) {
+ int lev_v=level[v];
+ next.set(v,active[lev_v]);
+ active[lev_v]=v;
+ }
+
+ T flo=flow[e];
+
+ if ( flo >= exc ) {
+ /*A nonsaturating push.*/
+
+ flow.set(e, flo-exc);
+ excess.set(v, excess[v]+exc);
+ exc=0;
+ break;
+ } else {
+ /*A saturating push.*/
+
+ excess.set(v, excess[v]+flo);
+ exc-=flo;
+ flow.set(e,0);
+ }
+ } else if ( newlevel > level[v] ) {
+ newlevel = level[v];
+ }
+ } //for in edges vw
+
+ } // if w still has excess after the out edge for cycle
+
+ excess.set(w, exc);
+
+ /*
+ Relabel
+ */
+
+
+ if ( exc > 0 ) {
+ //now 'lev' is the old level of w
+
+ if ( phase ) {
+ level.set(w,++newlevel);
+ next.set(w,active[newlevel]);
+ active[newlevel]=w;
+ b=newlevel;
+ } else {
+ //unlacing starts
+ Node right_n=right[w];
+ Node left_n=left[w];
+
+ if ( G.valid(right_n) ) {
+ if ( G.valid(left_n) ) {
+ right.set(left_n, right_n);
+ left.set(right_n, left_n);
+ } else {
+ level_list[lev]=right_n;
+ left.set(right_n, INVALID);
+ }
+ } else {
+ if ( G.valid(left_n) ) {
+ right.set(left_n, INVALID);
+ } else {
+ level_list[lev]=INVALID;
+ }
+ }
+ //unlacing ends
+
+ if ( !G.valid(level_list[lev]) ) {
+
+ //gapping starts
+ for (int i=lev; i!=k ; ) {
+ Node v=level_list[++i];
+ while ( G.valid(v) ) {
+ level.set(v,n);
+ v=right[v];
+ }
+ level_list[i]=INVALID;
+ if ( !what_heur ) active[i]=INVALID;
+ }
+
+ level.set(w,n);
+ b=lev-1;
+ k=b;
+ //gapping ends
+
+ } else {
+
+ if ( newlevel == n ) level.set(w,n);
+ else {
+ level.set(w,++newlevel);
+ next.set(w,active[newlevel]);
+ active[newlevel]=w;
+ if ( what_heur ) b=newlevel;
+ if ( k < newlevel ) ++k; //now k=newlevel
+ Node first=level_list[newlevel];
+ if ( G.valid(first) ) left.set(first,w);
+ right.set(w,first);
+ left.set(w,INVALID);
+ level_list[newlevel]=w;
+ }
+ }
+
+
+ ++relabel;
+ if ( relabel >= heur ) {
+ relabel=0;
+ if ( what_heur ) {
+ what_heur=0;
+ heur=heur0;
+ end=false;
+ } else {
+ what_heur=1;
+ heur=heur1;
+ b=k;
+ }
+ }
+ } //phase 0
+
+
+ } // if ( exc > 0 )
+
+
+ } // if stack[b] is nonempty
+
+ } // while(true)
+
+
+ value = excess[t];
+ /*Max flow value.*/
+
+ } //void run()
+
+
+
+
+
+ /*
+ Returns the maximum value of a flow.
+ */
+
+ T flowValue() {
+ return value;
+ }
+
+
+ FlowMap Flow() {
+ return flow;
+ }
+
+
+
+ void Flow(FlowMap& _flow ) {
+ NodeIt v;
+ for(G.first(v) ; G.valid(v); G.next(v))
+ _flow.set(v,flow[v]);
+ }
+
+
+
+ /*
+ Returns the minimum min cut, by a bfs from s in the residual graph.
+ */
+
+ template<typename _CutMap>
+ void minMinCut(_CutMap& M) {
+
+ std::queue<Node> queue;
+
+ M.set(s,true);
+ queue.push(s);
+
+ while (!queue.empty()) {
+ Node w=queue.front();
+ queue.pop();
+
+ OutEdgeIt e;
+ for(G.first(e,w) ; G.valid(e); G.next(e)) {
+ Node v=G.head(e);
+ if (!M[v] && flow[e] < capacity[e] ) {
+ queue.push(v);
+ M.set(v, true);
+ }
+ }
+
+ InEdgeIt f;
+ for(G.first(f,w) ; G.valid(f); G.next(f)) {
+ Node v=G.tail(f);
+ if (!M[v] && flow[f] > 0 ) {
+ queue.push(v);
+ M.set(v, true);
+ }
+ }
+ }
+ }
+
+
+
+ /*
+ Returns the maximum min cut, by a reverse bfs
+ from t in the residual graph.
+ */
+
+ template<typename _CutMap>
+ void maxMinCut(_CutMap& M) {
+
+ std::queue<Node> queue;
+
+ M.set(t,true);
+ queue.push(t);
+
+ while (!queue.empty()) {
+ Node w=queue.front();
+ queue.pop();
+
+
+ InEdgeIt e;
+ for(G.first(e,w) ; G.valid(e); G.next(e)) {
+ Node v=G.tail(e);
+ if (!M[v] && flow[e] < capacity[e] ) {
+ queue.push(v);
+ M.set(v, true);
+ }
+ }
+
+ OutEdgeIt f;
+ for(G.first(f,w) ; G.valid(f); G.next(f)) {
+ Node v=G.head(f);
+ if (!M[v] && flow[f] > 0 ) {
+ queue.push(v);
+ M.set(v, true);
+ }
+ }
+ }
+
+ NodeIt v;
+ for(G.first(v) ; G.valid(v); G.next(v)) {
+ M.set(v, !M[v]);
+ }
+
+ }
+
+
+
+ template<typename CutMap>
+ void minCut(CutMap& M) {
+ minMinCut(M);
+ }
+
+
+ void reset_target (Node _t) {t=_t;}
+ void reset_source (Node _s) {s=_s;}
+
+ template<typename _CapMap>
+ void reset_cap (_CapMap _cap) {capacity=_cap;}
+
+ template<typename _FlowMap>
+ void reset_cap (_FlowMap _flow, bool _constzero) {
+ flow=_flow;
+ constzero=_constzero;
+ }
+
+
+
+ };
+
+} //namespace hugo
+
+#endif //PREFLOW_H
+
+
+
+
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