[petsc-users] How to combine different element types into a single DMPlex?

[Karin&NiKo]

Dear Eric, dear Matthew,

I share Eric's desire to be able to manipulate meshes composed of different
types of elements in a PETSc's DMPlex.
Since this discussion, is there anything new on this feature for the
DMPlex object or am I missing something?

Thanks,
Nicolas

Le mer. 21 juil. 2021 à 04:25, Eric Chamberland <
Eric.Chamberland at giref.ulaval.ca> a écrit :

> Hi,
> On 2021-07-14 3:14 p.m., Matthew Knepley wrote:
>
> On Wed, Jul 14, 2021 at 1:25 PM Eric Chamberland <
> Eric.Chamberland at giref.ulaval.ca> wrote:
>
>> Hi,
>>
>> while playing with DMPlexBuildFromCellListParallel, I noticed we have to
>> specify "numCorners" which is a fixed value, then gives a fixed number
>> of nodes for a series of elements.
>>
>> How can I then add, for example, triangles and quadrangles into a DMPlex?
>>
>
> You can't with that function. It would be much mich more complicated if
> you could, and I am not sure
> it is worth it for that function. The reason is that you would need index
> information to offset into the
> connectivity list, and that would need to be replicated to some extent so
> that all processes know what
> the others are doing. Possible, but complicated.
>
> Maybe I can help suggest something for what you are trying to do?
>
> Yes: we are trying to partition our parallel mesh with PETSc functions.
> The mesh has been read in parallel so each process owns a part of it, but
> we have to manage mixed elements types.
>
> When we directly use ParMETIS_V3_PartMeshKway, we give two arrays to
> describe the elements which allows mixed elements.
>
> So, how would I read my mixed mesh in parallel and give it to PETSc DMPlex
> so I can use a PetscPartitioner with DMPlexDistribute ?
>
> A second goal we have is to use PETSc to compute the overlap, which is
> something I can't find in PARMetis (and any other partitionning library?)
>
> Thanks,
>
> Eric
>
>
>
>   Thanks,
>
>       Matt
>
>
>
>> Thanks,
>>
>> Eric
>>
>> --
>> Eric Chamberland, ing., M. Ing
>> Professionnel de recherche
>> GIREF/Université Laval
>> (418) 656-2131 poste 41 22 42
>>
>>
>
> --
> 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
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>
> --
> Eric Chamberland, ing., M. Ing
> Professionnel de recherche
> GIREF/Université Laval
> (418) 656-2131 poste 41 22 42
>
>
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