[petsc-users] A question about DMPlexDistribute

[Matthew Knepley]

On Thu, Aug 11, 2016 at 3:14 AM, leejearl <leejearl at 126.com> wrote:

> Hi,
>     Thank you for your reply. It help me very much.
>     But, for "/petsc-3.7.2/src/ts/examples/tutorials/ex11.c", when I set
> the overlap to 2 levels, the command is
> "mpirun -n 3 ./ex11 -f annulus-20.exo -ufv_mesh_overlap 2 -physics sw", it
> suffers a error.
>     It seems to me that setting overlap to 2 is very common. Are there
> issues that I have not take into consideration?
>     Any help are appreciated.
>
I will check this out. I have not tested an overlap of 2 here since I
generally use nearest neighbor FV methods for
unstructured stuff. I have test examples that run fine for overlap > 1. Can
you send the entire error message?

If the error is not in the distribution, but rather in the analytics, that
is understandable because this example is only
intended to be run using a nearest neighbor FV method, and thus might be
confused if we give it two layers of ghost
cells.

   Matt


>
> leejearl
>
> On 2016年08月11日 14:57, Julian Andrej wrote:
>
> Hi,
>
> take a look at slide 10 of [1], there is visually explained what the
> overlap between partitions is.
>
> [1] https://www.archer.ac.uk/training/virtual/files/2015/
> 06-PETSc/slides.pdf
>
> On Thu, Aug 11, 2016 at 8:48 AM, leejearl <leejearl at 126.com> wrote:
>
>> Hi, all:
>>     I want to use PETSc to build my FVM code. Now, I have a question about
>> the function  DMPlexDistribute(DM dm, PetscInt overlap, PetscSF *sf, DM
>> *dmOverlap) .
>>
>>     In the example "/petsc-3.7.2/src/ts/examples/tutorials/ex11.c". When
>> I set the overlap
>> as 0 or 1, it works well. But, if I set the overlap as 2, it suffers a
>> problem.
>>     I am confused about the value of overlap. Can it be set as 2? What is
>> the meaning of
>> the parameter overlap?
>>     Any helps are appreciated!
>>
>> leejearl
>>
>>
>>
>>
>
>


-- 
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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