[Gmsh] progress with CGNS boundary data

[Nigel Nunn]

Dear Professor Geuzaine,

Thank you for your reply, and many thanks also to Stepen Guzik.

Stepen's code in MZone and MZoneBoundary is the most spectacular use of
standard containers I have ever seen.  For interest, I built a cgns lib
(VC++ 2008), and after a simple change in MZoneBoundary (replacing embedded
FaceT with a pointer to FaceT), writeCGNS(...) runs and writes without
fuss.  That embedded FaceT object caused undefined behaviour in the custom
memory management of CCon::FaceVector<T>.  Only problem is I have no
software to *read* cgns, so cannot confirm or deny correctness.

However, by reusing MZone and MZoneBoundary to assemble the mesh
topology, I've added GModel::writeNEU(...) to export in gambit neutral
format (*.neu).  This gives the face-boundary data required by Tim
Warburton's family of multi-GPU DG solvers.  As a first test, I have these
solvers communicating with the gmsh gui via sockets (as suggested by the
docs).  Run-time rendering of solution fields is working fine.  Also, added
a button to Pause/Resume the client process.

Nigel


On Wed, Aug 4, 2010 at 7:11 AM, Christophe Geuzaine <cgeuzaine at ulg.ac.be>wrote:


> Hi Nigel - I've always been intrigued by CGNS, but never had a chance to
> look it up in detail. The CGNS code in Gmsh was contributed by Stepen Guzik
> (in CC). His code is quite complex: he's probably the best person to
> contact.
>
>
> On 24/07/10 21:17, Nigel Nunn wrote:
>


>  Hi to gmsh developers,
>>
>> The svn code for writeCGNS looks great.  I’m stepping through it trying to
>> get the region-surface boundary data our solver needs.
>>
>> I've found a few places where unexpected things happen.  Is there someone
>> among the active developers currently interested in sorting this out, or
>> simply interested in getting face boundary data?
>>
>> To export such data directly from Netgen, we had to call
>> mesh.UpdateTopology() which builds all the necessary data structures. It
>> looks like something similar is being done in GModelIO_CGNS.cpp by zoneTask?
>>
>> If anyone is interested in discussing this, please let me know.  I think I
>> failed to subscribe to the mailing list, so might be best to also email me
>> at nnnunnn at gmail.com
>>
>> thanks for all the great stuff in gmsh!
>> Nigel
>>
>>
>
> --
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>
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