[petsc-users] import a mesh.

[Matthew Knepley]

On Tue, Aug 20, 2013 at 10:16 AM, Olivier Bonnefon <
olivier.bonnefon at avignon.inra.fr> wrote:

>  Hello,
>
> Thank-you, I'm using DMPlexCreateFromCellList(), and it works except for
> the boundary conditions.
> I'm using Dirichlet boundary conditions, and the corresponding degree of
> freedom are not substituted (like when I use DMPlexCreateBoxMesh).
> So, I do have missing a step to define the boundary ?
>

Yes. For the other formats, it translates boundary markers to DMLabels.
With the CellList you will have to label your boundary.
If you want it to work exactly as in the example, for every point p on your
boundary,

  DMPlexSetLabelValue(dm, "marker", p, 1);

You can avoid the string lookup by using

  DMPlexCreateLabel(dm, "marker");
  DMPlexGetLabel(dm, "marker", &label);
  DMLabelSetValue(label, p, 1);

Obviously, if you have multiple BC, you can use a label for each condition.

  Thanks,

     Matt


> Olivier B
>
>
> On 08/20/2013 03:08 PM, Matthew Knepley wrote:
>
> On Tue, Aug 20, 2013 at 7:50 AM, Olivier Bonnefon <
> olivier.bonnefon at avignon.inra.fr> wrote:
>
>> Hello,
>>
>> I have modify the ex12.c example for a like diffusive problem
>> (FEM+unstructured mesh+SNES).
>> The next step, is to replace the square mesh by my own mesh.
>> I want import my mesh from a simple file, and after distributed it with
>> DMPlexDistribute.
>> Is it the good way ?
>> Is it possible to import a mesh in petsc ? I didn't find the answer in
>> the documentation. Is there an example ?
>>
>
>  There are a few formats supported:
>
>    1) Cell-vertex: DMPlexCreateFromCellList()
>
>    2) Exodus: DMPlexCreateExodus()
>
>    3) CGNS: DMPlexCreateCGNS()
>
>    Thanks,
>
>       Matt
>
>
>> Thanks
>> Olivier Bonnefon
>>
>> --
>> Olivier Bonnefon
>> INRA PACA-Avignon, Unité BioSP
>> Tel: +33 (0)4 32 72 21 58 <%2B33%20%280%294%2032%2072%2021%2058>
>>
>>
>
>
>  --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
>
>
> --
> Olivier Bonnefon
> INRA PACA-Avignon, Unité BioSP
> Tel: +33 (0)4 32 72 21 58
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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