source: lemon-0.x/src/work/jacint/max_matching.cc @ 1062:8226427845bc

///Generates a random graph, and tests max_matching.h on it.
#include <iostream>
#include <queue>
#include <math.h>

#include <list_graph.h>
#include <dimacs.h>
#include <graph_gen.h>
#include <max_matching.h>
#include <time_measure.h>
#include <graph_wrapper.h>

using namespace lemon;

int main(int, char **) {
 
  typedef UndirGraph<ListGraph> UGW;
  typedef UGW::Edge Edge;
  typedef UGW::EdgeIt EdgeIt;
  typedef UGW::OutEdgeIt OutEdgeIt;
  typedef UGW::NodeIt NodeIt;
  typedef UGW::Node Node;
   
  UGW G;

  //  random_init(); //If you want to use a random graph with a random
  //  number of edges and nodes.

  int i;
  int j;
  std::cout<<"Number of nodes: ";
  std::cin >> i;
  std::cout<<"Number of edges: ";
  std::cin >> j;

  //  readDimacs(std::cin, G); 
  randomGraph(G, i, j );  

  Timer ts;
  bool noerror=true;
  
  std::cout <<
    "\n  Testing max_matching.h on a random graph with " << 
    G.nodeNum() << " nodes and " << G.edgeNum() << " edges...\n"
            << std::endl;
  MaxMatching<UGW> max_matching(G);

 
  std::cout << 
    "Running the plain edmonds algorithm runEdmonds(0) using no heuristic... " 
            <<std::endl;
  ts.reset();  
  max_matching.runEdmonds(0);
  std::cout<<"Elapsed time: "<<ts<<std::endl;
  int s=0;
  UGW::NodeMap<Node> mate(G,INVALID);
  max_matching.writeNMapNode(mate);
  NodeIt v;
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( G.valid(mate[v]) ) {
      ++s;
    }
  }
  int size=(int)s/2;  //size will be used as the size of a maxmatching
  std::cout << size << " is the size of the matching found by runEdmonds(0),"<<std::endl;
  if ( size == max_matching.size() ) {
    std::cout<< "which equals to the size of the actual matching reported by size().\n"<< std::endl;
  } else {  
    std::cout<< "which does not equal to the size of the actual matching reported by size()!\n"<< std::endl;
    noerror=false;
  }


  std::cout<<"Writing the position by calling writePos...";
  UGW::NodeMap<MaxMatching<UGW>::pos_enum> pos0(G);
  max_matching.writePos(pos0);
  std::cout << "OK" << std::endl;


  std::cout << "Resetting the matching and the position by calling"<< std::endl;
  std::cout<<"resetPos() and resetMatching()...";
  max_matching.resetPos();
  max_matching.resetMatching();
  std::cout <<"OK" << std::endl;


  std::cout << "\nRunning runEdmonds(1) using the 'postpone shrink' heuristic ... " <<std::endl;
  ts.reset();  
  max_matching.runEdmonds(1);
  std::cout<<"Elapsed time: "<<ts<<std::endl;
  s=0;
  max_matching.writeNMapNode(mate);
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( G.valid(mate[v]) ) {
      ++s;
    }
  }
  std::cout << (int)s/2 << 
    " is the size of the matching found by runEdmonds(1),"<<std::endl;
  if ( (int)s/2 == size ) {
    std::cout<< "which equals to the size of the matching found by runEdmonds(0)."<< std::endl;
  } else {  
    std::cout<< "which does not equal to the size of the matching found by runEdmonds(0)!"<< std::endl;
    noerror=false;
  } 
  UGW::NodeMap<MaxMatching<UGW>::pos_enum> pos1(G);
  max_matching.writePos(pos1);


  std::cout << "\nStarting run() from the matching given by runEdmonds(1)... " <<std::endl;
  max_matching.resetPos();
  ts.reset();  
  max_matching.run();
  std::cout<<"Elapsed time: "<<ts<<std::endl;
  s=0;
  max_matching.writeNMapNode(mate);
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( G.valid(mate[v]) ) {
      ++s;
    }
  }
  if ( (int)s/2 == size ) {
    std::cout<< "Found a matching of proper size."<< std::endl;
  } else {  
    std::cout<< "Found a matching of inproper size!"<< std::endl;
    noerror=false;
  }
  UGW::NodeMap<MaxMatching<UGW>::pos_enum> pos2(G);
  max_matching.writePos(pos2);


  std::cout << "\nCalling resetPos() and resetMatching()...";
  max_matching.resetPos();
  max_matching.resetMatching();
  std::cout<<"OK"<<std::endl;
  std::cout <<"Calling greedyMatching() and then runEdmonds(1)... " <<std::endl;
  ts.reset();  
  max_matching.run();
  std::cout<<"Elapsed time: "<<ts<<std::endl;
  s=0;
  max_matching.writeNMapNode(mate);
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( G.valid(mate[v]) ) {
      ++s;
    }
  }
  std::cout << (int)s/2 << " is the size of the matching found by run(),"<<std::endl;
  if ( (int)s/2 == size ) {
    std::cout<< "which equals to the size of the matching found by runEdmonds(0)."<< std::endl;
  } else {  
    std::cout<< "which does not equal to the size of the matching found by runEdmonds(0)!"<< std::endl;
    noerror=false;
  }
  UGW::NodeMap<MaxMatching<UGW>::pos_enum> pos(G);
  max_matching.writePos(pos);
   
  
  std::cout<<"\nChecking if the output is a matching...";
  bool ismatching=true;
  for(G.first(v); G.valid(v); G.next(v) )
    if ( G.valid(mate[v]) ) {
      Node u=mate[v];
      if (mate[u]!=v) ismatching=false; 
    }
  if ( ismatching ) std::cout<<"OK"<<std::endl;
  else std::cout<< "It is not a matching!"<< std::endl;
  noerror = noerror && ismatching;
  

  std::cout<<"\nChecking the dual..."<<std::endl;
    
  std::cout<<"Checking if the four position outputs coincide...";
  bool coincide=true;
  int err_node=0;
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( pos0[v] != pos1[v] || pos1[v]!=pos2[v] || pos2[v]!=pos[v] ) {
      ++err_node;
      coincide=false;
    }
  }
  if ( coincide ) std::cout << "OK" <<std::endl;
  else {
    std::cout << "They do not coincide! Number of erroneous nodes: " 
              << err_node << std::endl;
  }     
  noerror=noerror && coincide;


  std::cout<<"Checking if there is no edge between D and C...";
  bool noedge=true;
  EdgeIt e;
  for(G.first(e); G.valid(e); G.next(e) ) {
    if ( (pos[G.target(e)]==max_matching.C && pos[G.source(e)]==max_matching.D) || 
         (pos[G.target(e)]==max_matching.D && pos[G.source(e)]==max_matching.C) )
      noedge=false; 
  }
  if ( noedge ) std::cout<<"OK"<<std::endl;
  else std::cout<< "There are edges between D and C!"<< std::endl;
  noerror = noerror && noedge;


  std::cout<<"Checking if all the components of G[D] are odd...";
  bool oddcomp=true;
  UGW::NodeMap<bool> todo(G,true);
  int num_comp=0;
  for(G.first(v); G.valid(v); G.next(v) ) {
    if ( pos[v]==max_matching.D && todo[v] ) {
      int comp_size=1;
      ++num_comp;
      std::queue<Node> Q;
      Q.push(v);
      todo.set(v,false);
      while (!Q.empty()) {
        Node w=Q.front();       
        Q.pop();
        OutEdgeIt e;
        for(G.first(e,w); G.valid(e); G.next(e)) {
          Node u=G.bNode(e);
          if ( pos[u]==max_matching.D && todo[u] ) {
            ++comp_size;
            Q.push(u);
            todo.set(u,false);
          }
        }
      }
      if ( !(comp_size % 2) ) oddcomp=false;  
    }
  }
  std::cout << "\n  found     " << num_comp << "     component(s) of G[D],";
  if ( oddcomp ) std::cout<<" each is odd."<<std::endl;
  else std::cout<< " but not all are odd!"<< std::endl;
  noerror = noerror && oddcomp;


  int barrier=0;
  for(G.first(v); G.valid(v); G.next(v) ) 
    if ( pos[v]==max_matching.A ) ++barrier;
  std::cout << barrier << " is the number of nodes in A (i.e. the size of the barrier), so" << std::endl;
  std::cout << num_comp - barrier << " is the deficiency of the graph, and hence" << std::endl; 
  int expected_size=(int)(G.nodeNum()-num_comp+barrier)/2;
  std::cout << expected_size << " should be the size of the maximum matching," << std::endl; 
  if ( size==expected_size )
    std::cout<<"which equals to the number of vertices missed by the found matching!"<<std::endl; 
  else {
    std::cout<<"which does not equal to the number of vertices missed by the matchings found!"
             <<std::endl; 
    noerror=false;
  }


  if ( num_comp == 1 && barrier == 0 ) 
    std::cout<<"\nThis graph is factor-critical."<<std::endl;
  if ( num_comp == 0 && barrier == 0 ) 
    std::cout<<"\nThis graph has a perfect matching."<<std::endl;


  if( noerror ) std::cout<<"\nNo errors found.\n"<<std::endl;
  else std::cout<<"\nSome errors found!\n"<<std::endl;

  return 0;
}