warshall.H

# ifndef WARSHALL_H
# define WARSHALL_H

# include <tpl_graph.H>
# include <tpl_matgraph.H>

namespace Aleph {

    template <class GT, class SA = Dft_Show_Arc<GT> >
void warshall_compute_transitive_clausure(GT &                    g, 
                                          Bit_Mat_Graph<GT, SA> & mat)
{
  Bit_Mat_Graph<GT, SA> mat_prev(g);
  if (mat.get_list_graph() != &g)
    mat.set_list_graph(g);
  const size_t & n = mat.get_num_nodes();
  for (int k = 0; k < n; k++) 
    {
      for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
          mat(i, j) = mat_prev(i, j) or
                      (mat_prev(i, k) and mat_prev(k, j));

      mat_prev = mat;
    }
}

    template <class GT, class SA = Dft_Show_Arc<GT> >
class Warshall_Compute_Transitive_Clausure
{ 
public:

  void operator () (GT & g, Bit_Mat_Graph<GT> & mat) const
  {
    warshall_compute_transitive_clausure <GT, SA> (g, mat);
  }
};

} // end namespace Aleph
# endif // WARSHALL_H