[petsc-users] Metis partitioning question

[Matthew Knepley]

On Thu, Aug 4, 2011 at 11:31 PM, Tabrez Ali <stali at geology.wisc.edu> wrote:

> Hello
>
> If a mesh is partitioned using Metis but the original order of nodes is
> used to create/partition the matrix then would this be significantly bad for
> performance and scalability.
>

That depends. Many mesh generators h ave fairly good ordering on output, but
some do not. Definitely a bad order can make a huge
difference in performance, both for cache traffic and conditioning reasons.


> Also is there an example that uses Metis to partition an unstructured mesh?
>

This depends on what you mean. If you can encode your mesh as a Mat, you can
use MatPartitoning. If not,
you would need to use DMMesh things, such as SNES ex12.

    Matt


> Thanks in advance.
>
> Tabrez

-- 
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
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