egonet_com.cpp

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#define NS_INFOMAP
#include <Infomap.h>
#include "network.hpp"

size_t NumCommunities( const Network& net ) {
  infomap::Infomap iwrapper("-2 -z -s 1234 --silent");
  // infomap::Infomap iwrapper("-2 --overlapping -s 1234"); // if I specify `overlapping`, a bus error occurs
  for( const Network::Link& l: net.m_links ) {
    iwrapper.addLink(l.m_node_id1, l.m_node_id2, l.m_weight);
  }
  iwrapper.run();
  return iwrapper.tree.numTopModules();
  /*
  for(infomap::LeafIterator leafIt(&iwrapper.tree.getRootNode()); !leafIt.isEnd(); ++leafIt) {
    std::cout << leafIt->originalLeafIndex << " " << leafIt.moduleIndex() << '\n';
  }
   */
}

void CountHistogram( std::map<size_t,size_t>& histo, size_t x ) {
  if( histo.find(x) != histo.end() ) {
    histo[x] += 1;
  } else {
    histo[x] = 1;
  }
}

int main( int argc, char* argv[]) {
  if (argc != 2 && argc != 3) {
    std::cerr << "Usage : " << argv[0] << " <edge_file> [num_nodes]" << std::endl;
    exit(1);
  }

  Network network;
  std::ifstream fin(argv[1]);
  std::cerr << "loading input file" << std::endl;
  network.LoadFile(fin);

  size_t num_egos = network.NumConnectedNodes();
  if( argc == 3 ) {
    num_egos = static_cast<size_t>( std::atol(argv[2]) );
  }

  std::cerr << "extracting ego-centric networks" << std::endl;
  double sum = 0.0;
  long count = 0;
  std::map<size_t,size_t> histo;
  for( size_t i=0; i<num_egos; i++) {
    if( network.m_nodes[i].Degree() == 0 ) { continue; }
    const Network ego_net = network.EgocentricNetworkWithoutEgo(i);
    size_t nc;
    if( ego_net.NumEdges() == 0 ) {
      nc = ego_net.m_nodes.size();
    }
    else {
      const Network ego_net_c = ego_net.PruneIsolates();
      size_t num_isolates = ego_net.m_nodes.size() - ego_net_c.m_nodes.size();
      nc = NumCommunities(ego_net_c) + num_isolates;
    }
    sum += nc;
    count += 1;
    CountHistogram(histo, nc);
  }
  std::cout << "{ \"NumEgoCommunities\": " << sum / count << " }" << std::endl;
  std::cerr << "writing num_egocom_histo.dat" << std::endl;
  std::ofstream fout("num_egocom_histo.dat");
  for( auto kv: histo ) {
    fout << kv.first << ' ' << kv.second << std::endl;
  }
  fout.flush(); fout.close();

  return 0;
}