[Gmsh] Error due to many volumes

[Christophe Geuzaine]

Werner, Romain - I think I might understand where the problem comes 
from: does it only happen with the Netgen algorithm?



magpar wrote:
> Dear Romain,
> Dear Gmsh developers and users,
> 
> I can confirm Romain's problem and his solution:
> 
> http://www.geuz.org/pipermail/gmsh/2008/003316.html
> 
>>> Romain Quey wrote:
>>>> Dear Gmsh developers, dear all,
>>>>
>>>> Using gmsh 2.2.0 on Linux, I'm having the following error:
>>>>
>>>> $ gmsh -3 n1100-id1.geo
>>>> Info    : Parsing file 'n1100-id1.geo'
>>>> Error   : [on processor 0] Unable to open file 'n1100-id1.msh'
>>>>
>>>> My geo file contains many 'Volume' definitions (1100) -- see the  
>>>> attached example.
> 
> [...]
> 
>> You are right, the bug does not occur here, but when writing the mesh.
>>
>> However, I think the reason for the bug is really this one: when
>> increasing the max number of openable files per process on my system
>> (from 1024 to 1000000), I can successfully mesh the file.  I think that
>> if you run 'ulimit -n 1024' on your system, gmsh will crash too.
> 
> I observed similar problems with models with many volumes a while ago 
> and reported them on the gmsh mailing list:
> 
> http://www.geuz.org/pipermail/gmsh/2007/002946.html
> http://www.geuz.org/pipermail/gmsh/2007/002831.html
> http://www.geuz.org/pipermail/gmsh/2007/002826.html
> http://www.geuz.org/pipermail/gmsh/2007/002947.html
> http://www.geuz.org/search/search-geuz.cgi?q=magpar&ul=%2Fpipermail%2Fgmsh%2F&ps=10
> 
> Based on Romain's observation I tested his solution to increase the 
> resources (max. number of open files) on the shell and I can confirm 
> that this fixes my problems, too.
> 
> Here is an example (from one of my earlier posts) which exhibits the 
> problem (mesh generation is successful, but the msh file cannot be saved):
> http://www.geuz.org/pipermail/gmsh/attachments/20071214/5a438bd7/attachment-0005.gz
> 
> To make this increase in the resources permanent one has to modify the 
> limits in /etc/security/limits.conf by adding or modifying the line
> 
> *                hard    nofile          10000
> 
> After that it is necessary to login on a new shell or even reboot the 
> machine because new processes inherit this setting from the 
> process/shell which launches it.
> 
> So, finally the question is why gmsh keeps so many files open (one for 
> each volume!?) and how this could be fixed.
> 
> Thanks for the useful discussion and help on this mailing list which 
> fixed my problem, too!
> 
> Werner
> 


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine