text: // Copyright (C) 2006-2009 Dmitry Bufistov and Andrey Parfenov
  
  // Use, modification and distribution is subject to the Boost Software
  // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  
  #include <cassert>
  #include <ctime>
  #include <boost/random/mersenne_twister.hpp>
  #include <boost/random/uniform_real.hpp>
  #include <boost/graph/adjacency_list.hpp>
  #include <boost/graph/random.hpp>
  #include <boost/graph/howard_cycle_ratio.hpp>
  
  /**
   * @author Dmitry Bufistov
   * @author Andrey Parfenov
   */
  
  using namespace boost;
  typedef adjacency_list< listS, listS, directedS,
      property< vertex_index_t, int >,
      property< edge_weight_t, double, property< edge_weight2_t, double > > >
      grap_real_t;
  
  template < typename TG > void gen_rand_graph(TG& g, size_t nV, size_t nE)
  {
      g.clear();
      mt19937 rng;
      rng.seed(0 /*uint32_t(time(0))*/);  // Reproducable seed.
      boost::generate_random_graph(g, nV, nE, rng, true, true);
      boost::uniform_real<> ur(-1, 10);
      boost::variate_generator< boost::mt19937&, boost::uniform_real<> > ew1rg(
          rng, ur);
      randomize_property< edge_weight_t >(g, ew1rg);
      boost::uniform_int< size_t > uint(1, 5);
      boost::variate_generator< boost::mt19937&, boost::uniform_int< size_t > >
          ew2rg(rng, uint);
      randomize_property< edge_weight2_t >(g, ew2rg);
  }
  
  int main(int argc, char* argv[])
  {
      using std::cout;
      using std::endl;
      const double epsilon = 0.0000001;
      double min_cr, max_cr; /// Minimum and maximum cycle ratio
      typedef std::vector< graph_traits< grap_real_t >::edge_descriptor >
          ccReal_t;
      ccReal_t cc; /// critical cycle
  
      grap_real_t tgr;
      property_map< grap_real_t, vertex_index_t >::type vim
          = get(vertex_index, tgr);
      property_map< grap_real_t, edge_weight_t >::type ew1
          = get(edge_weight, tgr);
      property_map< grap_real_t, edge_weight2_t >::type ew2
          = get(edge_weight2, tgr);
  
      gen_rand_graph(tgr, 1000, 30000);
      cout << "Vertices number: " << num_vertices(tgr) << endl;
      cout << "Edges number: " << num_edges(tgr) << endl;
      int i = 0;
      graph_traits< grap_real_t >::vertex_iterator vi, vi_end;
      for (boost::tie(vi, vi_end) = vertices(tgr); vi != vi_end; vi++)
      {
          vim[*vi] = i++; /// Initialize vertex index property
      }
      max_cr = maximum_cycle_ratio(tgr, vim, ew1, ew2);
      cout << "Maximum cycle ratio is " << max_cr << endl;
      min_cr = minimum_cycle_ratio(tgr, vim, ew1, ew2, &cc);
      cout << "Minimum cycle ratio is " << min_cr << endl;
      std::pair< double, double > cr(.0, .0);
      cout << "Critical cycle:\n";
      for (ccReal_t::iterator itr = cc.begin(); itr != cc.end(); ++itr)
      {
          cr.first += ew1[*itr];
          cr.second += ew2[*itr];
          std::cout << "(" << vim[source(*itr, tgr)] << ","
                    << vim[target(*itr, tgr)] << ") ";
      }
      cout << endl;
      assert(std::abs(cr.first / cr.second - min_cr) < epsilon * 2);
      return EXIT_SUCCESS;
  }
  