[petsc-users] DMPlex overlap

[Matthew Knepley]

On Sat, Mar 27, 2021 at 9:27 AM Nicolas Barral <
nicolas.barral at math.u-bordeaux.fr> wrote:

> Hi all,
>

I promise to read this today. While I am doing that, I have a branch


https://gitlab.com/petsc/petsc/-/commits/knepley/feature-plex-vertex-mapping

which I think does the face labeling you want, but I have not tested it yet.

  Thanks,

    Matt


> First, I'm not sure I understand what the overlap parameter in
> DMPlexDistributeOverlap does. I tried the following: generate a small
> mesh on 1 rank with DMPlexCreateBoxMesh, then distribute it with
> DMPlexDistribute. At this point I have two nice partitions, with shared
> vertices and no overlapping cells. Then I call DMPlexDistributeOverlap
> with the overlap parameter set to 0 or 1, and get the same resulting
> plex in both cases. Why is that ?
>
> Second, I'm wondering what would be a good way to handle two overlaps
> and associated local vectors. In my adaptation code, the remeshing
> library requires a non-overlapping mesh, while the refinement criterion
> computation is based on hessian computations, which require a layer of
> overlap. What I can do is clone the dm before distributing the overlap,
> then manage two independent plex objects with their own local sections
> etc. and copy/trim local vectors manually. Is there a more automatic way
> to do this ?
>
> Thanks
>
> --
> Nicolas
>


-- 
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/>
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