[petsc-users] Use block Jacobi preconditioner with SNES

[Ali Reza Khaz'ali]

Thanks a lot. It is working as expected. However, splitting a block 
matrix over MPI processes, sometimes results in splitting one block over 
2 (or possibly more) processors. It causes the block Jacobi 
preconditioner (+Linear solver) to fail. Is there any way in PETSc to 
enforce a pre-specified array/matrix distribution over MPI processes? I 
want to distribute the array/matrix entries, so that no block is divided 
between two MPI processes.


Many Thanks,

Ali


On 9/7/2018 3:06 AM, Smith, Barry F. wrote:
> It is ready in the branch barry/add-mpivpbjacobi; please let me know if you have any difficulties
>
>     Barry
>
>
>> On Sep 6, 2018, at 4:48 PM, arkhazali at cc.iut.ac.ir wrote:
>>
>> Yes, I'd be grateful if MPI support could be added, please.
>>
>> Many thanks,
>> Ali
>>
>> ------ Original message------
>> From: Smith, Barry F.
>> Date: Fri, Sep 7, 2018 01:45
>> To: Ali Reza Khaz'ali;
>> Cc: PETSc;
>> Subject:Re: [petsc-users] Use block Jacobi preconditioner with SNES
>>
>>    I have not yet added this support, do you need it now?
>>
>>     Barry
>>
>>
>>> On Sep 6, 2018, at 4:12 PM, Ali Reza Khaz'ali
>>   wrote:
>>> I have to apologize for making this topic so lengthy. Is vpbjacobi supposed to work in parallel mode (with MPI)?
>>>
>>>
>>> On 8/30/2018 1:32 AM, Smith, Barry F. wrote:
>>>>> On Aug 29, 2018, at 3:48 PM, Ali Reza Khaz'ali
>>   wrote:
>>>>>
>>>>>>     Can you confirm if your code ran successfully with vpbjacobi and if the convergence history was very similar to that achieved using
>>>>>> bjacobi ?
>>>>> They have a very very very small difference (which is probably due to round-off errors), they generally behave the same. My code run successfully with both of them with the same convergence history. However, vpbjacobi  seems a little faster.
>>>>     Great, this is exactly what to expect. I will put the branch into next for testing and then it will be in the master branch and in the next release.
>>>>
>>>>     Barry
>>>>
>>>>> Many thanks,
>>>>> Ali
>>> -- 
>>> Ali Reza Khaz’ali
>>> Assistant Professor of Petroleum Engineering,
>>> Department of Chemical Engineering
>>> Isfahan University of Technology
>>> Isfahan, Iran
>>>
>>

-- 
Ali Reza Khaz’ali
Assistant Professor of Petroleum Engineering,
Department of Chemical Engineering
Isfahan University of Technology
Isfahan, Iran