CGAL users discussion list

[Roya Rahmati <>]

Hello,

I am using periodic Delaunay triangulation in my code, and producing for each vertex all neighboring vertices. For this I use Edge iterator, since in my case it will be much more faster than Vertex iterator.

But, in some of my simulations, especially for particle numbers<1000 instead of one special neighbor for each vertex I get 8 or 9 or ... copy of the same neighbor. For example I get something like this for the vertex 0:  Nei[0]=[2,2,2,2,2,2,2,2,4,4,4,...]

I couldn't find an example using edge iterator in CGAL website, and nothing related in stackoverflow. I am wondering whether this implementation is correct? What should I add to my code in order to get one copy per each neighbor, I can use STL::set, but I would like to know the source of problem.

A possible work around would be to replicate main simulation box, and use non-periodic version.

here is the code snippet:

    typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;

    typedef CGAL::Periodic_2_triangulation_traits_2<Kernel> Gt;

    typedef CGAL::Triangulation_vertex_base_with_info_2<unsigned int, Gt> Vb;

    typedef CGAL::Periodic_2_triangulation_face_base_2<Gt> Fb;

    typedef CGAL::Triangulation_data_structure_2<Vb, Fb> Tds;

    typedef CGAL::Periodic_2_Delaunay_triangulation_2<Gt, Tds> Triangulation;

    typedef Triangulation::Iso_rectangle Iso_rectangle;

    typedef Triangulation::Edge_iterator Edge_iterator;

    typedef Triangulation::Vertex_handle Vertex_handle;

    typedef Triangulation::Point Point;

    typedef vector<pair<Point, unsigned> > Vector_Paired;

    Vector_Paired points;

    Iso_rectangle domain(0,0,L,L);

    for(int iat = 0; iat < N; iat++)

        {

     points.push_back(make_pair(Point(r_tot[iat][0],r_tot[iat][1]),iat));

        }

    Triangulation T(points.begin(), points.end(), domain);

    for(Edge_iterator ei=T.finite_edges_begin(); ei!=T.finite_edges_end(); ei++)

        {

         

          Triangulation::Face& f = *(ei->first);

          int ii = ei->second;

          Vertex_handle vi = f.vertex(f.cw(ii));     

          Vertex_handle vj = f.vertex(f.ccw(ii));    

          int iat = vi->info();

          int jat = vj->info();

          VecInd[iat].push_back(jat);

          VecInd[jat].push_back(iat);

             

        }

Regards,