[petsc-users] DMLabel Synchronize

[Matthew Knepley]

On Tue, Aug 30, 2022 at 6:37 PM Nicholas Arnold-Medabalimi <
narnoldm at umich.edu> wrote:

> Hi
>
> Thanks for all the help. I'm looking to tag several cells based on metrics
> occurring at run time. In addition to the metric-defined cells I also want
> to label the surrounding cells. This is no problem as I can traverse the
> DMPlex chart to get the neighboring cells. The issue only arises if an
> identified cell is on a partition boundary. this leads to the neighbor
> cell in the overlap halo being tagged. However, the root cell on the
> adjacent partition is not tagged. Is there a built-in way to synchronize
> the labels from the leafs to the roots?
>
> Right now, I iterate through the root and leaf cells of each processor,
> but it is somewhat wasteful as I don't see a way for the root cell
> partition to know if a corresponding leaf cell label value without
> communicating it first.
>

What I think you want is this:

  https://petsc.org/main/docs/manualpages/DMLabel/DMLabelPropagateBegin/

I use this to do the same kind of labeling I think. It is setup to allow
multiple rounds,
so that you can use the communicated labeling to continue on the new rank.

Will this work?

  Thanks,

     Matt


> Thanks
> Nicholas
>
> --
> Nicholas Arnold-Medabalimi
>
> Ph.D. Candidate
> Computational Aeroscience Lab
> University of Michigan
>


-- 
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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