CGAL users discussion list

["Garth N. Wells" <>]

On 8 February 2012 19:17, Garth N. Wells 
<>
 wrote:
> On 8 February 2012 10:43, Laurent Rineau (GeometryFactory)
> <>
>  wrote:
>> Le mardi 07 février 2012 12:22:52 Garth Wells a écrit :
>>> I've been running into some issues with mesh generation in 3D. I'm 
>>> creating
>>> meshes of rather simple polyhedra (tetrahedra, cubes), but have been 
>>> finding
>>> that the generation randomly fails at times. I'm also seeing a dependency
>>> on the gcc version and optimisation level. The code at the end of this
>>> message, taken from
>>>
>>>
>>> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.h
>>> tml#Subsection_50.3.5
>>>
>>> runs without error with g++ 4.6.1, but with g++ 4.4.6 and the -O2 or -O3
>>> flag I get the error
>>>
>>>     terminate called after throwing an instance of
>>> 'CGAL::Precondition_exception'
>>>       what():  CGAL ERROR: precondition violation!
>>>     Expr: index != Subdomain_index()
>>>     File: 
>>> /usr/include/CGAL/Mesh_3/Mesh_complex_3_in_triangulation_3_base.h
>>>     Line: 160
>>>     Aborted
>>>
>>> I've tested with CGAL 3.8 and 3.9. The code is compiled using
>>>
>>>     g++ -O2 -frounding-math  test.cpp -lCGAL -lboost_thread -lmpfr -lgmp
>>>
>>> Any help with this would be greatly appreciated.
>>
>> Can you please add:
>>
>> #define CGAL_MESH_3_VERBOSE 1
>>
>> as the first line of your cpp file, recompile, and give us the output of 
>> the
>> run, when it fails?
>>
>
> It get:
>
> Inserting protection balls...
> insert_corners() done. Nb of points in triangulation: 25
> insert_balls_on_edges() done. Nb of points in triangulation: 610
> refine_balls() done. Nb of points in triangulation: 616
>
> Start surface scan...end scan. [Bad facets:1202]
>
> Refining Surface...
> Legende of the following line: (#vertices,#steps,#facets to
> refine,#tets to refine)
> (1741,1124,0,0) (328.6 vertices/s)))
> Total refining surface time: 3.42021s
>
> Start volume scan...end scan. [Bad tets:2643]
>
> Refining...
> Legende of the following line: (#vertices,#steps,#facets to
> refine,#tets to refine)
> (1742,1,0,2642) (250.0 vertices/s)terminate called after throwing an
> instance of 'CGAL::Precondition_exception'
>  what():  CGAL ERROR: precondition violation!
> Expr: index != Subdomain_index()
> File: /usr/include/CGAL/Mesh_3/Mesh_complex_3_in_triangulation_3_base.h
> Line: 160
> Aborted
>

Considering that the failing example code comes from the CGAL
examples, I suppose that it should be considered a CGAL bug. Is there
a bug tracker where I can report it as a bug?

Garth

> Garth
>
>> --
>> Laurent Rineau, PhD
>> R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
>> Release Manager of the CGAL Project       http://www.cgal.org/
>>
>>
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>
>
>
> --
> Garth N. Wells
> Department of Engineering, University of Cambridge
> http://www.eng.cam.ac.uk/~gnw20