[petsc-users] Hypre + openMP

[Matthew Knepley]

On Wed, May 13, 2015 at 12:01 AM, Michele Rosso <mrosso at uci.edu> wrote:

> Thanks Matt,
> Could you give me an example of not-native partitioning? I have a cubic
> domain and a 3D domain decomposition. I use dmda3d to create the
> partitioning.
>
"naive", and I was talking about coarse grids. Coarse grids should be
partitioned onto fewer than P processes.

   Matt


> Thanks,
>
> Michele
> On May 12, 2015 9:51 PM, "Matthew Knepley" <knepley at gmail.com> wrote:
>
>> On Tue, May 12, 2015 at 11:41 PM, Michele Rosso <mrosso at uci.edu> wrote:
>>
>>> Barry,
>>>
>>> thanks for your answer. The reason I'm asking is that multigrid limits
>>> the number of MPI tasks I can use for a given grid, since k multigrid
>>> levels require at least 2^(k-1) grid nodes per direction. I was wondering
>>> if using OpenMP together with MPI could help circumventing the problem. If
>>> you have any other suggestions, it would be greatly appreciated.
>>>
>> This is only for naive partitioning. Good AMG necks down the processor
>> set correctly, for example GAMG in PETSc.
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> Best,
>>> Michele
>>>
>>>   You could compile hypre yourself with the OpenMP feature turned on and
>>> then configure PETSc to use that version of hypre; of course the rest of
>>> the PETSc code would not utilize the OpenMP threads.
>>>
>>>    Barry
>>>
>>> BTW: I don't know of any evidence that using hypre with OpenMP is
>>> superior to using hypre without so I aside from academic curiosity I don't
>>> think there would be a reason to do this.
>>>
>>> > On May 12, 2015, at 7:55 PM, Michele Rosso <mrosso at uci.edu> wrote:
>>> >
>>> > Hi,
>>> >
>>> > is it possible to use the openmp capabilities of hypre via petsc?
>>> > Thanks,
>>> >
>>> > Michele
>>>
>>>
>>
>>
>> --
>> 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
>>
>


-- 
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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