src/work/jacint/preflow.cc
author alpar
Sat, 17 Apr 2004 13:15:53 +0000
changeset 348 b63ea19e502e
parent 211 9222a9b8b323
child 372 e6a156fc186d
permissions -rw-r--r--
A bool Edge Map with iterators that goes through the true or the false edges.
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#include <iostream>
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#include <fstream>
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#include <smart_graph.h>
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#include <list_graph.h>
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#include <dimacs.h>
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#include <preflow.h>
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#include <time_measure.h>
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using namespace hugo;
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// Use a DIMACS max flow file as stdin.
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// read_dimacs_demo < dimacs_max_flow_file
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int main(int, char **) {
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  typedef SmartGraph::Node Node;
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  typedef SmartGraph::EdgeIt EdgeIt;
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  SmartGraph G;
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  Node s, t;
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  SmartGraph::EdgeMap<int> cap(G);
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  readDimacsMaxFlow(std::cin, G, s, t, cap);
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  std::cout << "preflow demo ..." << std::endl;
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  double mintime=1000000;
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  for ( int i=1; i!=11; ++i ) {
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    SmartGraph::EdgeMap<int> flow(G);
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    double pre_time=currTime();
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    Preflow<SmartGraph, int> max_flow_test(G, s, t, cap, flow);
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    max_flow_test.run();
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    double post_time=currTime();
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    if ( mintime > post_time-pre_time ) mintime = post_time-pre_time;
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  }
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  SmartGraph::EdgeMap<int> flow(G);
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  Preflow<SmartGraph, int> max_flow_test(G, s, t, cap, flow);
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  max_flow_test.run();
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  SmartGraph::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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  EdgeIt e;
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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)]) min_cut_value+=cap[e];
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  }
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  SmartGraph::NodeMap<bool> cut1(G);
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  max_flow_test.minMinCut(cut1); 
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  int min_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_min_cut_value+=cap[e];
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  }
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  SmartGraph::NodeMap<bool> cut2(G);
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  max_flow_test.maxMinCut(cut2); 
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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 (cut2[G.tail(e)] && !cut2[G.head(e)]) 
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      max_min_cut_value+=cap[e];
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      }
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  std::cout << "min time of 10 runs: " << mintime << " sec"<< 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<< std::endl;
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  return 0;
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}