[Trilinos-Users] Question concerning the Epetra BlockMap function : RemoteIDList
John Jomo
john.jomo at tum.de
Thu Sep 17 14:12:16 EDT 2015
Hallo Mike,
thanks for the quick reply,
I checked the error codes and the function always returned 0.
I am calling the function about 15 times on every processes with a
different set of indices.
When running 4 MPI processes, two processes successfully complete all 15
calls while two processes both have only 14 successfull calls and dont
return on the last call causing a deadlock. Putting a MPI barrier right
after the end of the function doesn't help.
John.
On 17.09.2015 19:32, Heroux, Mike wrote:
> John,
>
> A few thoughts:
>
> - Generally speaking, this is a collective call, so all MPI processes need
> to participate in the call. Some logic paths through the function don¹t
> require communication if the situation is simple enough to compute with
> local data.
> - Check error codes to see if there is a non-zero value being returned.
>
> Mike
>
> On 9/17/15, 11:09 AM, "Trilinos-Users on behalf of John Jomo"
> <trilinos-users-bounces at trilinos.org on behalf of john.jomo at tum.de> wrote:
>
>> Hallo everyone,
>>
>> here is a question concerning Epetra:
>>
>> I have created a distributed Epetra_BlockMap and I'm trying to find out
>> on which processes a set of Ids reside using the RemoteIDList command.
>>
>> I run a loop over the function making repeated queries using different
>> values of "IdsToQuery"
>> int error = myMap->RemoteIDList( numberOfIds, &( IdsToQuery[0] ), &(
>> processorIds[0] ), &( localIds[0] ));
>>
>> For some strange reason some processes find all Ids while others stall
>> within the function causing a deadlock :(
>>
>> I thought the problem was caused by mutlithreading so I pinned the
>> mpi-processes to the cores and made sure that I only used one process
>> per core. This however did not solve the problem.
>>
>> Would really appreciate some help on this.
>>
>> thanks in advance
>>
>>
>> John.
>>
>>
>>
>> --
>> John Jomo M.Sc.
>> Technische Universität München
>> Computation in Engineering
>> Simulation in Applied Mechanics - SAM
>> Arcisstraße 21
>> 80333 München
>> Tel.: 0049 / 89 / 289 25064
>> Fax: 0049 / 89 / 289 25051
>> E-Mail:john.jomo at tum.de<mailto:john.jomo at tum.de>
>> Internet:www.cie.bgu.tum.de<http://www.cie.bgu.tum.de/>
>>
>> _______________________________________________
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--
John Jomo M.Sc.
Technische Universität München
Computation in Engineering
Simulation in Applied Mechanics - SAM
Arcisstraße 21
80333 München
Tel.: 0049 / 89 / 289 25064
Fax: 0049 / 89 / 289 25051
E-Mail: john.jomo at tum.de<mailto:john.jomo at tum.de>
Internet: www.cie.bgu.tum.de<http://www.cie.bgu.tum.de/>
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