CGAL users discussion list

[Song Lin <>]

Hi,

the typedef part of my codes are:

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kk;
typedef CGAL::Regular_triangulation_euclidean_traits_3<Kk> Gt;
typedef CGAL::Alpha_shape_vertex_base_3<Gt> Vb_as;
typedef CGAL::Triangulation_vertex_base_with_info_3<int, Kk, Vb_as> Vb;
typedef CGAL::Alpha_shape_cell_base_3<Gt> Cb_as;
typedef CGAL::Triangulation_cell_base_with_info_3<int, Kk, Cb_as> Cb;
typedef CGAL::Triangulation_data_structure_3<Vb,Cb> Tds;
typedef CGAL::Regular_triangulation_3<Gt,Tds> Triangulation_3;
typedef CGAL::Alpha_shape_3<Triangulation_3> Alpha_shape_3;

typedef Alpha_shape_3::Cell_handle          Cell_handle;
typedef Alpha_shape_3::Vertex_handle        Vertex_handle;
typedef Alpha_shape_3::Facet                Facet;
typedef Alpha_shape_3::Edge                 Edge;
typedef Gt::Weighted_point                  Weighted_point;
typedef Gt::Bare_point                      Bare_point;



for a cell in Alpha_shape_3,

Alpha_shape_3::Finite_cells_iterator cit;



I tried to modify the info() of its neighbors:

for (int i=0;i<4;i++)
{
        cit->neighbor(i)->info()=1;
}



but after I ran the program and checked the info():

for (cit = as.finite_cells_begin(); cit != as.finite_cells_end();cit++)
{
        if(cit->neighbor(i)->info()==1)
}

I found nothing was changed. It seems that cit->neighbor(i) returns a
"copy" of cit->neighbor(i) but not cit->neighbor(i) itself. (So that
nothing in Alpha_shape_3 was changed.) 

Any one can tell me how to modify cit->neighbor(i)? (so that
Alpha_shape_3 was changed as well?)


Best regards,
Lin

-- 
Center of Computational and Systems Biology, 
Institute of Biophysics, CAS.
15 Datun Road, Chaoyang District
Beijing, 100101
P.R.China