[Trilinos-Users] [EXTERNAL] RE: Teuchos::TimeMonitor::summarize problem with local communicators

[Dicharry, Will]

On 12/8/11 1:52 PM, "Mark Hoemmen" <mhoemme at sandia.gov> wrote:

>On Dec 8, 2011, at 1:30 PM, Bartlett, Roscoe A. wrote:
>> Question below ...
>> 
>>>> Is there a special reason why the summarize method takes more or less
>>>> automatically the MPI_COMM_WORLD communicator.
>>> 
>>> 1. Because it was a legacy interface which I got stuck supporting ;-)
>>> 
>>> 2. So that summarize() works in packages that have no communicator
>>> concept (e.g., Anasazi and Belos).
>>> 
>>>> I'm working with a split communicator and not all of my processes
>>>> call the summarize. Hence, some of my processes wait in front of
>>>>several
>>>> "barrier (*pComm)" calls within the summarize but the remaining
>>>> processes will never reach these barriers and my whole simulation
>>>>stops.
>>>> 
>>>> An alternative would be to add a further argument to the summarize
>>>> method that includes a potential local communicator. The default can
>>>>of
>>>> course be the MPI_COMM_WORLD.
>>> 
>>> This is not very hard for us to do.  We may have to give the new
>>>method a
>>> different name or otherwise change the interface so as to retain
>>>backwards
>>> compatibility.
>>> 
>>> I'm the person who would likely have to implement this.  You are
>>>welcome to
>>> communicate with me directly regarding the urgency of this request, so
>>>that I
>>> can prioritize tasks.
>> 
>> [Bartlett, Roscoe A.]
>> 
>> Can you use Teuchos::Comm instead of raw MPI for this?
>
>Of course! :-)  I would only use Teuchos::Comm and not raw MPI
>communicators.  I just want to give the question-asker a chance to let me
>know how urgent this is and provide some interface input.

I'm not sure if it's relevant, but the question-asker mentioned using a
split communicator, which is not available in the Teuchos::Comm interface
in the 10.8 release, but *is* available in master right now (it was
implemented at the beginning of October). Without that change, you have to
go through some minor contortions to use a split communicator via
Teuchos::Comm.

-- Will

>
>mfh
>
>
>
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