[mpich-discuss] New communicator from connect/accept primitives

[Dave Goodell]

I haven't read through your code yet to try and spot any bugs, but you  
should probably try running on a more recent version of mpich2.   
Version 1.0.5 is several years old and could easily have a bug in some  
of the intercommunicator code (because it is so infrequently used)  
that has since been fixed.  I also know for sure that several dynamic  
process bugs have been fixed since the 1.0.5 timeframe.

-Dave

On Jan 18, 2010, at 10:26 AM, Francisco Javier García Blas wrote:

> Hello again,
>
> In first place, thanks for response of Rajeev and Jayesh. Following  
> Rajeev 's instruccion,  I implemented an basic example using connect/ 
> accept and intercomm_create/merge primitives. I am doing something  
> wrong because when MPI_Intercomm_create is invoked, all the  
> processes become blocked. I don't find the error, maybe it could be  
> a bad numeration in local and remote communicator but I tried all  
> the combinations.
>
> I am using mpich2 1.0.5.
>
> I attach the source code and a makefile.
>
> Best regards
>
> Rajeev Thakur escribió:
>> You will need to use intercomm_merge but you have to merge them one  
>> pair at a time. Example below from an old mail.
>> Rajeev
>>  If you have 3 intercommunicators AB_inter, AC_inter, and AD_inter,  
>> you can merge them all into a single
>> intercommunicator as follows:
>> * begin by doing an MPI_Intercomm_merge on AB_inter, resulting in an
>> intracommunicator AB_intra.
>> * then create an intercommunicator between AB on one side and C on  
>> the other
>> by using MPI_Intercomm_create. Pass AB_intra as the local_comm on A  
>> and B,
>> MPI_COMM_WORLD as the intracomm on C, and AC_inter as the  
>> peer_comm. This
>> results in the intercommunicator AB_C_inter.
>> * then call MPI_Intercomm_merge on it to create the intracommunicator
>> ABC_intra.
>> * then call MPI_Intercomm_create to create an intercommunicator  
>> between ABC
>> and D just as you did with AB and C above.
>> * Again do an intercomm_merge. This will give you an  
>> intracommunicator
>> containing A, B, C, D.
>> * If you want an intercommunicator with A in one group and B,C,D in  
>> the
>> other, as you would get with a single spawn of 3 processes, you  
>> have to call
>> MPI_Comm_split to split this single communicator into two
>> intracommunicators, one containing A and the other containing  
>> B,C,D. Then
>> call MPI_Intercomm_create to create the intercommunicator.
>>
>>     
>> ------------------------------------------------------------------------
>>    *From:* mpich-discuss-bounces at mcs.anl.gov
>>    [mailto:mpich-discuss-bounces at mcs.anl.gov] *On Behalf Of
>>    *Francisco Javier García Blas
>>    *Sent:* Friday, January 15, 2010 11:09 AM
>>    *To:* mpich-discuss at mcs.anl.gov
>>    *Subject:* [mpich-discuss] New communicator from connect/accept
>>    primitives
>>
>>    Hello all,
>>
>>    I wondering the possibility of get a new inter-comunicator from N
>>    communicators, which are results from different calls of
>>    mpi_comm_connect or mpi_comm_accept.
>>
>>    My initial solution was first,  to get the group of each
>>    inter-communicator with mpi_comm_group, second, to join all the
>>    groups into one bigger and finally, to create a new communicator
>>    from the group with the mpi_comm_create primitive.
>>    Currently I am handling a pool of inter - communicators in order
>>    to keep the functionality. However this idea is not suitable for
>>    collective and MPI_ANY_SOURCE sends/recvs.
>>
>>    Exist another way to join all the inter-communicator into one?
>>    Any suggestion?
>>
>>    Best regards.
>>
>>
>>
>>
>>    --------------------------------------------------
>>    Francisco Javier García Blas
>>    Computer Architecture, Communications and Systems Area.
>>    Computer Science Department. UNIVERSIDAD CARLOS III DE MADRID
>>    Avda. de la Universidad, 30
>>    28911 Leganés (Madrid), SPAIN
>>    e-mail: fjblas at arcos.inf.uc3m.es <mailto:fjblas at arcos.inf.uc3m.es>
>>                  fjblas at inf.uc3m.es <mailto:fjblas at inf.uc3m.es>
>>    Phone:(+34) 916249118
>>    FAX: (+34) 916249129
>>    --------------------------------------------------
>>
>> ------------------------------------------------------------------------
>>
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>
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