src/work/jacint/max_flow_bug.cc
author athos
Fri, 25 Mar 2005 15:32:05 +0000
changeset 1262 61f989e3e525
parent 921 818510fa3d99
permissions -rw-r--r--
This was a bug, I guess
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#include <iostream>
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//#include <lemon/list_graph.h>
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#include <sage_graph.h>
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#include <lemon/dimacs.h>
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#include <lemon/max_flow.h>
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//#include <max_flow_no_stack.h>
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#include <lemon/time_measure.h>
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using namespace lemon;
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int main(int, char **) {
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//  typedef ListGraph Graph;
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  typedef SageGraph Graph;
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  typedef Graph::Node Node;
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  typedef Graph::EdgeIt EdgeIt;
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  Graph G;
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  Node s, t;
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  Graph::EdgeMap<int> cap(G);
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  Graph::EdgeMap<int> flow(G,0);
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  readDimacs(std::cin, G, cap, s, t, flow);
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  Timer ts;
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  std::cout <<
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    "\n  Running max_flow.h on a graph with " << 
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    G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
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	   << std::endl<<std::endl;
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  MaxFlow<Graph, int> max_flow_test_no_stack(G, s, t, cap, flow);
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  ts.reset();
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  max_flow_test_no_stack.preflowPhase1(MaxFlow<Graph, int>::PRE_FLOW);
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  std::cout << "Elapsed time of run() without stack: " << std::endl 
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	    <<ts << std::endl;
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  Graph::NodeMap<bool> mincut(G);
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  max_flow_test_no_stack.minMinCut(mincut); 
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  int min_min_cut_value=0;
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  EdgeIt e;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (mincut[G.source(e)] && !mincut[G.target(e)]) min_min_cut_value+=cap[e];
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  }
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  Graph::NodeMap<bool> cut(G);
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  max_flow_test_no_stack.minCut(cut); 
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  int min_cut_value=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (cut[G.source(e)] && !cut[G.target(e)]) 
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      min_cut_value+=cap[e];
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  }
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  Graph::NodeMap<bool> maxcut(G);
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  max_flow_test_no_stack.maxMinCut(maxcut); 
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  int max_min_cut_value=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (maxcut[G.source(e)] && !maxcut[G.target(e)]) 
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      max_min_cut_value+=cap[e];
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      }
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  std::cout << "\n Checking the result without stack: " <<std::endl;  
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  std::cout << "Flow value: "<< max_flow_test_no_stack.flowValue() << std::endl;
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  std::cout << "Min cut value: "<< min_cut_value << std::endl;
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  std::cout << "Min min cut value: "<< min_min_cut_value << std::endl;
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  std::cout << "Max min cut value: "<< max_min_cut_value << 
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    std::endl;
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  if ( max_flow_test_no_stack.flowValue() == min_cut_value &&
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       min_cut_value == min_min_cut_value &&
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       min_min_cut_value == max_min_cut_value )
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    std::cout << "They are equal! " <<std::endl<< std::endl<<"\n";  
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  /*
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  Graph::EdgeMap<int> flow2(G,0);
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  std::cout << "Calling setFlow() " << std::endl 
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	    << ts << std::endl;
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  max_flow_test.setFlow(flow2);  
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  ts.reset();
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  max_flow_test.preflow(max_flow_test.PRE_FLOW);
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  std::cout << "Elapsed time of preflow(PRE_FLOW) starting from the zero flow: " << std::endl 
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	    << ts << std::endl;
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  Graph::NodeMap<bool> mincut2(G);
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  max_flow_test.minMinCut(mincut2); 
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  int min_min_cut_value2=0;
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    for(G.first(e); G.valid(e); G.next(e)) {
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    if (mincut2[G.source(e)] && !mincut2[G.target(e)]) min_min_cut_value2+=cap[e];
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  }
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  Graph::NodeMap<bool> cut2(G);
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  max_flow_test.minCut(cut2); 
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  int min_cut_value2=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (cut2[G.source(e)] && !cut2[G.target(e)]) 
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      min_cut_value2+=cap[e];
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  }
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  Graph::NodeMap<bool> maxcut2(G);
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  max_flow_test.maxMinCut(maxcut2); 
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  int max_min_cut_value2=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (maxcut2[G.source(e)] && !maxcut2[G.target(e)]) 
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      max_min_cut_value2+=cap[e];
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      }
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  std::cout << "\n Checking the result: " <<std::endl;  
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  std::cout << "Flow value: "<< max_flow_test.flowValue() << std::endl;
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  std::cout << "Min cut value: "<< min_cut_value2 << std::endl;
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  std::cout << "Min min cut value: "<< min_min_cut_value2 << std::endl;
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  std::cout << "Max min cut value: "<< max_min_cut_value2 << 
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    std::endl;  
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  if ( max_flow_test.flowValue() == min_cut_value &&
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       min_cut_value == min_min_cut_value &&
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       min_min_cut_value == max_min_cut_value )
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    std::cout << "They are equal! " <<std::endl;  
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  MaxFlow<Graph, int> max_flow_test3(G, s, t, cap, flow2);
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  max_flow_test3.run(max_flow_test3.GEN_FLOW);
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  std::cout << "Calling run(GEN_FLOW) from the max flow found before. " <<std::endl;  
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  Graph::NodeMap<bool> mincut3(G);
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  max_flow_test3.minMinCut(mincut3); 
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  int min_min_cut_value3=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (mincut3[G.source(e)] && !mincut3[G.target(e)]) min_min_cut_value3+=cap[e];
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  }
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  Graph::NodeMap<bool> cut3(G);
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  max_flow_test3.minCut(cut3); 
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  int min_cut_value3=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (cut3[G.source(e)] && !cut3[G.target(e)]) 
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      min_cut_value3+=cap[e];
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  }
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  Graph::NodeMap<bool> maxcut3(G);
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  max_flow_test3.maxMinCut(maxcut3); 
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  int max_min_cut_value3=0;
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  for(G.first(e); G.valid(e); G.next(e)) {
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    if (maxcut3[G.source(e)] && !maxcut3[G.target(e)]) 
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      max_min_cut_value3+=cap[e];
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  }
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  std::cout << "\n Checking the result: " <<std::endl;  
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  std::cout << "Flow value: "<< max_flow_test3.flowValue() << std::endl;
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  std::cout << "Min cut value: "<< min_cut_value3 << std::endl;
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  std::cout << "Min min cut value: "<< min_min_cut_value3 << std::endl;
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  std::cout << "Max min cut value: "<< max_min_cut_value3 << 
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    std::endl;
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  if ( max_flow_test3.flowValue() == min_cut_value3 &&
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       min_cut_value3 == min_min_cut_value3 &&
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       min_min_cut_value3 == max_min_cut_value3 )
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    std::cout << "They are equal! " <<std::endl<< std::endl<<"\n";  
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  */
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  return 0;
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}