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

[Rajeev Thakur]

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
              fjblas at inf.uc3m.es
Phone:(+34) 916249118
FAX: (+34) 916249129
--------------------------------------------------


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/mpich-discuss/attachments/20100115/9b85cae7/attachment.htm>