[petsc-users] (no subject)

[Matthew Knepley]

On Sun, Mar 3, 2013 at 4:39 AM, <ztdep at yahoo.com.cn> wrote:

>
>     I am writting a parallel unstructured FVM solver for fluid flow
> problem, but i met some problems when i compute the gradient of a variable
> using Gauss's theorem.
>     As we know,we need the values of a variable at all its neighboring
> cells, but if one of my neighbouring cell is not in the local processor,
> how to get it.
>  Could you please give me some advices.
>

You can see our example of a parallel unstructured FVM solver in TS ex11 in
petsc-dev.

Specifically, I can see several ways to do this. You could partition faces,
and have ghost cells, which we can handles. Or
you could partition cells, and assemble these kind of function over faces
additively if they are linear, which I think yours is,
which is what we do in ex11. It depends on your particular application, but
we have the tools to do this.

   Thanks,

      Matt


> Regards
> Your Sincerely
>
>


-- 
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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