Multiple communicators

[Matthew Knepley]

On Tue, Nov 24, 2009 at 7:56 PM, <irfan.khan at gatech.edu> wrote:

> I don't explicitly use the communicator PETSC_COMM_WORLD.  Instead I used
> MPI_COMM_WORLD, which according to the manual should be the same.
>
> However, I create two new communicator from MPI_COMM_WORLD using
> MPI_Comm_split(). LBM_Comm and FEA_Comm. Only the ranks in FEA_Comm make use
> of KSP solver and PARMETIS. When creating objects for mesh partitioning
> (MatPartitioningCreate()) and solver (KSPCreate()), I use the new
> communicator FEA_Comm. Would this have any effect on the command line
> options?
>

No.

  Matt


> Regards
> Irfan
>
>
>
> I am not sure what you are doing, but something is wrong in this code.
> Using different communicators does not
> have much to do with options. Any object (like a KSP) can be created using
> a subcomm of WORLD. Are you
> setting PETSC_COMM_WORLD to something different? That is not necessary
> here.
>
>   Matt
>
>
>
>
>> Thank you
>> Irfan
>>
>> ----- Original Message -----
>> From: "Matthew Knepley" <knepley at gmail.com>
>> To: "PETSc users list" <petsc-users at mcs.anl.gov>
>> Sent: Tuesday, November 24, 2009 8:03:00 PM GMT -05:00 US/Canada Eastern
>> Subject: Re: Multiple communicators
>>
>> On Tue, Nov 24, 2009 at 6:59 PM, <irfan.khan at gatech.edu> wrote:
>>
>>> Hello
>>>
>>> Does the procedure for providing command line options and to obtain
>>> profiling data through -log_summary change if there are multiple MPI
>>> communicators in a petsc code?
>>>
>>
>> There is always WORLD, so it should be fine unless I misunderstand your
>> question.
>>
>>   Matt
>>
>>
>>> If so, can somebody point me to information, references on how to provide
>>> command line options if there are multiple communicators?
>>>
>>> Thank you
>>> Irfan
>>>
>>> --
>>> PhD Candidate
>>> G.W. Woodruff School of Mechanical Engineering
>>> Georgia Institute of Technology
>>> Atlanta, GA (30332)
>>>
>>
>>
>>
>> --
>> 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
>>
>>
>> --
>> PhD Candidate
>> G.W. Woodruff School of Mechanical Engineering
>> Georgia Institute of Technology
>> Atlanta, GA (30332)
>>
>
>
>
> --
> 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
>
>
> --
> PhD Candidate
> G.W. Woodruff School of Mechanical Engineering
> Georgia Institute of Technology
> Atlanta, GA (30332)
>



-- 
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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