CGAL users discussion list

[Sylvain Pion <>]

Matthijs Sypkens Smit a écrit :
> On Monday 05 November 2007 09:16, Sylvain Pion wrote:
>
> > Matthijs Sypkens Smit a écrit :
> > > Dear all,
> > >
> > > The CGAL triangulations allow you to check whether a cell or vertex is
> > > part of the triangulation. I could not find similar functionality for
> > > the CGAL polyhedron (polyhedral surface). When I store a bunch of
> > > vertex, halfedge or facet handles, how do I check whether the handle
> > > is still valid before trying to investigate the data structure at that
> > > element?
> > Iterate over all elements of the polyhedron until you find it?
>
> I was hoping for a somewhat more efficient method. I presume by your answer 
> that none exists.

Currently nothing better than that.  The triangulation only provide the
functions by convenience, more than by better algorithms.
It should be possible for triangulations to get an answer in O(sqrt(n))
instead of O(n) though, by exploiting the underneath memory layout
(see Compact_container).  This is for Triangulation, not Polyhedron.

Of course, if you have a fast point location available with your
polyhedron, then you can build on it.

--
Sylvain Pion
INRIA Sophia-Antipolis
Geometrica Project-Team
CGAL, http://cgal.org/

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