CGAL users discussion list

[Mariette Yvinec <>]

For a facet incident to two finite cells,
 the dual is a segment joigning the (weighted) circumcenters)
of incident cells. In degenerate situations, it may happen
that both circumcenters are located on the same point.



Le 27/06/11 09:09, Sebastien Loriot (GeometryFactory) a écrit :
> How did you check that the source and target of the segment
> are equal?
>
> If you checked it with an assertion in the code, then we probably need
> to get a minimal example showing the problem to provide you a fix.
>
> Sebastien.
>
> randooom wrote:
> > tl;dr: see subject line
> >
> > Following a little explanation what I try to accomplish and why.
> >
> > I have a Regular_triangulation_3 rt and want to extract the power 
> > diagram
> > cell by cell (and only the finite ones).
> >
> > My algorithm is basically as follows:
> >
> > CellContainer cells
> >
> > foreach finite_vertex fv in rt:
> >     foreach incident_cell ic to fv:
> >         check if ic is infinite.
> >     if no_infinite_incident_cell_found
> >         MyCell mc            foreach incident_vertex iv of fv:
> >             MyFacet mf
> >             get edge e with rt.is_edge(fv, iv, ...)
> >             circulate over incident_facets if of e:
> >                 Segment_3 s = (Object cast and so forth) rt.dual(if) 
> > // [1]                              mf.addEdge(s)
> >             mc.addFacet(mf)
> >         cells.addCell(mc)
> >
> > [1] at this point I sometimes get a Segment_3 s with identical 
> > s.source()
> > and s.target(). How can this be, and what can I do about it? This makes
> > really no sense to me... :)
> >
> > Thank you for you time reading this and I hope someone can help me; 
> > any tips
> > and suggestions are much appreciated!
> >
> > --
> > View this message in context: 
> > http://cgal-discuss.949826.n4.nabble.com/Why-does-Regular-triangulation-3-dual-Facet-f-sometimes-return-a-edge-with-identical-source-and-targ-tp3625888p3625888.html
> > Sent from the cgal-discuss mailing list archive at Nabble.com.

--
Mariette Yvinec
Geometrica project team
INRIA  Sophia-Antipolis