src/work/jacint/preflow_res_comp.cc
author jacint
Mon, 26 Apr 2004 17:05:22 +0000
changeset 422 ede61a3d229b
permissions -rw-r--r--
macro erase
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/*
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The only difference between preflow.h and preflow_res.h is that the latter
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uses the ResGraphWrapper, while the first does not. (Bfs is implemented by
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hand in both.) This test program runs Preflow and PreflowRes on the same
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graph, tests the result of these implementations and writes the running time
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of them.  */
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#include <iostream>
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#include <smart_graph.h>
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#include <dimacs.h>
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#include <preflow.h>
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#include <preflow_res.h>
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#include <time_measure.h>
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using namespace hugo;
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int main(int, char **) {
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  typedef SmartGraph 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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  readDimacsMaxFlow(std::cin, G, s, t, cap);
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  Timer ts;
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  std::cout <<
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    "\n  In which way are we faster: using ResGraphWrapper or not?"
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	    <<std::endl;
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  std::cout <<
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    "\n  Running preflow.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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  Graph::EdgeMap<int> flow(G,0);
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  Preflow<Graph, int> max_flow_test(G, s, t, cap, flow, 1);
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  ts.reset();
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  max_flow_test.run();
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  std::cout << "Elapsed time NOT using the ResGraphWrapper: " << 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.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.tail(e)] && !mincut[G.head(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.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.tail(e)] && !cut[G.head(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.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.tail(e)] && !maxcut[G.head(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: " <<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_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.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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  Graph::EdgeMap<int> flow2(G,0);
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  PreflowRes<Graph, int> max_flow_test2(G, s, t, cap, flow2, 1);
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  ts.reset();
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  max_flow_test2.run();
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  std::cout << "Elapsed time using the ResGraphWrapper: " << std::endl 
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	    << ts << std::endl;
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  Graph::NodeMap<bool> mincut2(G);
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  max_flow_test2.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.tail(e)] && !mincut2[G.head(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_test2.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.tail(e)] && !cut2[G.head(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_test2.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.tail(e)] && !maxcut2[G.head(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_test2.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<<"/n";  
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  return 0;
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}