CGAL users discussion list

[Manuel Caroli <>]

Thomas Zangl wrote:
> Well, I now have some issues with the iterators. I want to catch all 
> possible (finite) faces of all cells:
[...]
> AFAIK this should work. I visite all cells and mark their finite faces 
> with some info.
>
> Now I iterate over them:
>
>   for(Rt_Finite_facet_iterator fIt = t.finite_facets_begin(); fIt != 
> t.finite_facets_end(); fIt++) {
>
>     Rt_Cell_handle cell = fIt->first;
>     // this is the index of the facet's opposite vertex
>     int faceIndex = fIt->second;
>
>     // do some work ..
>     // mark them all as singular
>     cell->info().faces[faceIndex] = fsSingular;
>     cell->neighbor(faceIndex)->info().faces[faceIndex] = fsSingular;
>
> }
>
> As you can see, I iterate over all finite faces and mark them as 
> "singular". I even mark the same face but viewed from the neighbor cell. 
> Is that true?
You don't necessarily choose the right facet from the neighboring cell.
Try something like
  cell->neighbor(faceIndex)
        ->info().faces[cell->neighbor(faceIndex)->index(cell)]
                = fsSingular;
I just wrote it down like this, please check with the documentation.

> So there is some difference between iterating over all cells and visit 
> each facet of the cell and iterating over all facets and mark the facet 
> and its opposite?
No, there shouldn't be.