CGAL users discussion list

[Sylvain Pion <>]

Jens K. Becker wrote:
> I have a pretty strange problem. I have written a numerical simulation
> software (or better I am trying to) that uses CGAl (especially the
> polyhedra and therewith hds) a lot. The program compiles fine but does
> not work (it always crashes when trying to remove halfedges (using
> join_facets). If I run it in valgrind, it perfectly works.
> Valgrind is a software that can be used to check for memory-leaks (there
> are none) etc..
>
>  From wikipedia.org:
> ...
> Valgrind is in essence a virtual machine using just-in-time (JIT) (aka
> binary translation) compilation techniques. Nothing from the original
> program ever gets run directly on the host processor.
> ...
>
>
> So far so good, but now I have absolutely NO idea where to look for what
> goes wrong (and why). Any ideas?

Valgrind does not emulate FPU rounding modes which are used to implement
interval arithmetic.  The later being used in filtered kernels which you
can find in many places in CGAL.  A solution is to used either inexact
fast non-robust, risky, use-at-your-own-risk, may-or-may-not-work-for-you
kernels e.g. Simple_cartesian<double>, or a slow exact kernel, e.g.
Simple_cartesian<Gmpq>.  That may be enough for debugging.

The ideal solution would be to ping the valgrind developers (again),
so that they work on supporting this missing feature.

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

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