CGAL users discussion list

[Guillaume Damiand <>]

Le 31/10/2013 23:40, Phil Weir a écrit :
> On 30/10/13 17:28, Phil Weir wrote:
> > On 10/17/2013 05:57 PM, Garth N. Wells wrote:
> > > What I'm doing is surface meshing a sphere, converting the surface 
> > > mesh to a polyhedron, and trying to generate a volume mesh of the 
> > > polyhedron (the motivation is to add/subtract polyhedra to create 
> > > more complicated domains). The code that reproduces the error (using 
> > > CGAL 4.2 and GCC 4.8) is attached. The code is basically a 
> > > concatenation of the demos in sections 48.3.1 and 51.3.2. Any 
> > > suggestions to get this working?
> > >
> > > Garth
> >
> > Actually, I have just had a very similar problem the last couple of 
> > days, same abort message - I rebuilt CGAL 4.2, with identical source 
> > to the working version, and it appeared. The old binary still runs 
> > fine. CGAL 4.2 and 4.3 show the same thing with the 
> > mesh_polyhedral_domain demo. A fresh compile of CGAL 4.3 on an Ubuntu 
> > 12.04 virtual box has no problems. As such, I suspect there may be 
> > something with library versions.
> A related problem with the same code turned out to be this bug in the 
> version of the STL libraries 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58800 that is now default 
> on Ubuntu 13.10. I have not confirmed whether the underlying cause is 
> related to the problem above too, but this particular one was 
> occurring during conversion of a polyhedron to a Nef polyhedron - K3 
> tree calls std::nth_element, which in turn calls an introselect routine.
>
> This routine runs past the iterator end in a small percentage of cases 
> where it picks out a (critically) bad pivot. As K3 tree hits this 
> routine a lot of times for a large polyhedron, it seems to fairly 
> consistently kill my code for non-trivial tests - the comparison 
> operator dereferences the iter and CGAL::assign fails to cast it. The 
> upshot is a segfault below K3_tree.h:116-8 when trying to pull out the 
> point value of a vertex for comparison - if anybody else sees this, 
> that may be why.
>
> I don't know if anybody else is currently trying CGAL on Ubuntu 13.10, 
> but I could imagine that causing non-obvious bugs in other 
> geometry-building places too.

I tried, and observed similar problems (segfault or memory problems) in 
triangulation_3 package.

It seems to work with gcc 4.7 also provided in ubuntu 13.10 but I did 
only few tests...

Best
Guillaume

> Best,
> PTW


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Guillaume DAMIAND

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