[petsc-users] flux vector

[Matthew Knepley]

On Mon, Jun 14, 2021 at 11:34 PM Adrian Croucher <a.croucher at auckland.ac.nz>
wrote:

> hi
> On 15/06/21 12:21 pm, Matthew Knepley wrote:
>
>
> I admit that it is becoming complicated, but this can also be handled.
>
> The corner case only shows up when we distribute with overlap. Thus we
> could,
>
> 1) Distribute the mesh without overlap
>
> 2) Mark the global boundary using the former algorithm
>
> 3) Distribute overlap = 1 using DMPlexDistributeOverlap().
> DMPlexDistribute() just does these two steps at once if you ask for overlap.
>
> 4) Use the former algorithm, with the boundary label we just made, to mark
> flux faces.
>
> That sounds like it might work. Do you think this perhaps slightly simpler
> version might also work?
>
> 1) distribute mesh without overlap
>
> 2) label boundary faces using DMPlexMarkBoundaryFaces()
>
> 3) DMPlexDistributeOverlap()
>
> 4) Un-label boundary faces with support size > 1 (i.e. the shared faces on
> the non-overlapped mesh- I think) - so the boundary label is now just the
> global boundary
>
> 5) loop over faces as in my original algorithm, labelling flux faces if
> they are either on the open boundary, or are not on the global boundary
>
> Unfortunately I can't test this at the moment - it looks like the Fortran
> interface for DMPlexDistributeOverlap() is missing?
>
Yes, that does sound simpler. I will get the Fotran interface up today. I
did not use the automatic version since we need to check for NULL.

  Thanks,

     Matt


> - Adrian
> --
>
> Dr Adrian Croucher
> Senior Research Fellow
> Department of Engineering Science
> University of Auckland, New Zealand
> email: a.croucher at auckland.ac.nz
> tel: +64 (0)9 923 4611
>
>

-- 
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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