[petsc-users] Node numbering in parallel partitioned mesh

[Matthew Knepley]

On Tue, May 2, 2023 at 8:25 AM Karthikeyan Chockalingam - STFC UKRI via
petsc-users <petsc-users at mcs.anl.gov> wrote:

> Hello,
>
>
>
> This is not exactly a PETSc question. I have a parallel partitioned finite
> element mesh. What are the steps involved in having a contiguous but unique
> set of node numbering from one partition to the next? There are nodes which
> are shared between different partitions. Moreover, this partition has to
> coincide parallel partition of PETSc Vec/Mat, which ensures data locality.
>
>
>
> If you can post the algorithm or cite a reference, it will prove helpful.
>

Somehow, you have to know what "nodes" are shared. Once you know this, you
can make a rule for numbering, such
as "the lowest rank gets the shared nodes". We encapsulate this ownership
relation in the PetscSF. Roots are owned,
and leaves are not owned. The rule above is not great for load balance, so
we have an optimization routine for the
simple PetscSF:
https://petsc.org/main/manualpages/DMPlex/DMPlexRebalanceSharedPoints/

  Thanks,

     Matt


> Many thanks.
>
>
>
> Kind regards,
>
> Karthik.
>
>
>


-- 
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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