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Subject: Re: [OMPI users] Dynamic process tutorials?
From: jody (jody.xha_at_[hidden])
Date: 2010-07-12 11:32:18


Hi Brian

Generally it is possible to create new communicators from existing ones
(see for instance the various MPI_GROUP_* functions and MPI_COMM_CREATE)

> Also, how can you specify with MPI_Comm_spawn/multiple() how do you
> specify IP addresses on which to start the processes?
I haven't tried it yet with spawning, but i'd think this would also be
done by a rankfile

> I would prefer not to use any of the MPI command-line utilities
> (mpirun/mpiexec) if that's possible.
If you don't like command-line utilities, you can write some graphic tool
which will call mpirun or mpiexec. But somewhere you have to tell OpenMPI
what to run on how many processors etc.

I'd suggest you take a look at the "MPI-The Complete Reference" Vol I and II

Jody

On Mon, Jul 12, 2010 at 5:07 PM, Brian Budge <brian.budge_at_[hidden]> wrote:
> Hi Jody -
>
> Thanks for the reply.  is there a way of "fusing" intercommunicators?
> Let's say I have a higher level node scheduler, and it makes a new
> node available to a COMM that is already running.  So the master
> spawns another process for that node.  How can the new process
> communicate with the other already started processes?
>
> Also, how can you specify with MPI_Comm_spawn/multiple() how do you
> specify IP addresses on which to start the processes?
>
> If my higher level node scheduler needs to take away a process from my
> COMM, is it good/bad for that node to call MPI_Finalize as it exits?
>
> I would prefer not to use any of the MPI command-line utilities
> (mpirun/mpiexec) if that's possible.
>
> Thanks,
>  Brian
>
> On Sat, Jul 10, 2010 at 11:53 PM, jody <jody.xha_at_[hidden]> wrote:
>> Hi Brian
>> When you spawn processes with MPI_Comm_spawn(), one of the arguments
>> will be set to an intercommunicator of thes spawner and the spawnees.
>> You can use this intercommunicator as the communicator argument
>> in the MPI_functions.
>>
>> Jody
>> On Fri, Jul 9, 2010 at 5:56 PM, Brian Budge <brian.budge_at_[hidden]> wrote:
>>> Hi all -
>>>
>>> I've been looking at the dynamic process features of mpi-2.  I have managed
>>> to actually launch processes using spawn, but haven't seen examples for
>>> actually communicating once these processes are launched.  I am additionally
>>> interested in how processes created through multiple spawn calls can
>>> communicate.
>>>
>>> Does anyone know of resources that describe these topics?  My google-fu must
>>> not be up to par :)
>>>
>>> Thanks,
>>>   Brian
>>>
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>
>>
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