Re: [OMPI users] Dynamic COMM_WORLD

2006-07-07 Thread Abhishek Agarwal


Hello,

I have done some work on this using MPICH which is very similar to OpenMPI 
usage.


The i think this is working as soon as you spawn a process it creates a 
intercommunicator and you can comunicate with the corresponding working 
using that intercommunicator. If you want to communicate between two workers 
then you will have to merge all the processes which communicate into one 
intra communicator and pass that particular intracommunicator during 
communication.


I hope this helps
Abhishek
Nortel Gov. Sol.


From: Eric Thibodeau <ky...@neuralbs.com>
Reply-To: Open MPI Users <us...@open-mpi.org>
To: us...@open-mpi.org
Subject: Re: [OMPI users] Dynamic COMM_WORLD
Date: Fri, 7 Jul 2006 14:49:04 -0400

Yes, I was interested in the example such as:

http://www-unix.mcs.anl.gov/mpi/mpi-standard/mpi-report-2.0/node98.htm#Node98

The way I see it, there are litteraly two programs, a Manager program and a
Worker program which is started by the manager (the example doesn't show if
multiple workers are started by repeated calls to the spawn command). I
unsderstand that MPI_COMM_WORLD is somewhat static but I am unclear as to 
how

to communicate with future-spawned process... Is there an MPI_COMM_UNIVERSE
that we can drop in place of the MPI_COMM_WORLD? It's also not clear who
would be part of MPI_COMM_PARENT other than the process that spawned the
worker.

Well, I know I have some reading to perform on the whole dynamic/spawning
process, my query was really to know if OpenMPI was up and ready in that
field of MPI2.

Thanks,

Eric


Le vendredi 7 juillet 2006 14:09, Edgar Gabriel a écrit :
> Eric Thibodeau wrote:
> > Hello all,
> >
> > Before I embark on a train that will run out of tracks, I wanted to
> > get a WFF concerning the spwaning mechanisme in OpenMPI. The intent
> > is that I would program a "simple" parallel application that would
> > demonstrate the ability of recent MPI implementations (OpenMPI) to
> > dynamically ADD or remove processes from the parallel task pool. Of
> > course, any documentation concerning these new features would also be
> > greatly appreciated ;)
>
> Open MPI supports spawning new processes as defined in the MPI-2
> specification, see e.g.
>
> 
http://www-unix.mcs.anl.gov/mpi/mpi-standard/mpi-report-2.0/mpi2-report.htm

>
> However, please note, that this does not modify MPI_COMM_WORLD.
> MPI_COMM_WORLD is a static communicator which can not be changed, even
> in Open MPI...
>
> Thanks
> Edgar
> ___
> users mailing list
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--
Eric Thibodeau
Neural Bucket Solutions Inc.
T. (514) 736-1436
C. (514) 710-0517

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Re: [OMPI users] Dynamic COMM_WORLD

2006-07-07 Thread Edgar Gabriel

Eric Thibodeau wrote:

Hello all,

Before I embark on a train that will run out of tracks, I wanted to
get a WFF concerning the spwaning mechanisme in OpenMPI. The intent
is that I would program a "simple" parallel application that would
demonstrate the ability of recent MPI implementations (OpenMPI) to
dynamically ADD or remove processes from the parallel task pool. Of
course, any documentation concerning these new features would also be
greatly appreciated ;)


Open MPI supports spawning new processes as defined in the MPI-2 
specification, see e.g.


http://www-unix.mcs.anl.gov/mpi/mpi-standard/mpi-report-2.0/mpi2-report.htm

However, please note, that this does not modify MPI_COMM_WORLD. 
MPI_COMM_WORLD is a static communicator which can not be changed, even 
in Open MPI...


Thanks
Edgar