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Subject: Re: [OMPI users] Newbie question
From: Terry Dontje (terry.dontje_at_[hidden])
Date: 2011-01-11 06:28:35


So are you trying to start an mpi job that one process is one executable
and the other process(es) are something else? If so, you probably want
to use a multiple app context. If you look at FAQ question 7. How do I
run an MPMD MPI Job at http://www.open-mpi.org/faq/?category=running
this should answer your question below I believe.

--td

On 01/11/2011 01:06 AM, Tena Sakai wrote:
> Hi,
>
> Thanks for your reply.
>
> I am afraid your terse response doesn’t shed much light. What I need
> is “hosts”
> parameter I can use to mpi.spawn.Rslaves() function. Can you explain
> or better
> yet give an example as to how I can get this via mpirun?
>
> Looking at mpirun man page, I found an example:
> mpirun –H aa,aa,bb ./a.out
> and similar ones. But they all execute a program (like a.out above).
> That’’s not
> what I want. What I want is to spawn a bunch of R slaves to other
> machines on
> the network. I can spawn R slaves, as many as I like, to the local
> machine, but
> I don’t know how to do this with machines on the network. That’s what
> “hosts”
> parameter of mpi.spawn.Rslaves() enables me to do, I think. If I can
> do that, then
> Rmpi has function(s) to send command to each of the spawned slaves.
>
> My question is how can I get open MPI to give me those “hosts” parameters.
>
> Can you please help me?
>
> Thank you in advance.
>
> Tena Sakai
> tsakai_at_[hidden]
>
>
> On 1/10/11 8:14 PM, "pooja varshneya" <pooja.varshneya_at_[hidden]> wrote:
>
> You can use mpirun.
>
> On Mon, Jan 10, 2011 at 8:04 PM, Tena Sakai
> <tsakai_at_[hidden]> wrote:
>
> Hi,
>
> I am an mpi newbie. My open MPI is v 1.4.3, which I compiled
> on a linux machine.
>
> I am using a language called R, which has an mpi
> interface/package.
> It appears that it is happy, on the surface, with the open MPI
> I installed.
>
> There is an R function called mpi.spawn.Rslaves(). An argument to
> this function is nslaves. I can issue, for example,
> mpi.spawn.Rslaves( nslaves=20 )
> And it spawns 20 slave processes. The trouble is that it is
> all on the
> same node as that of the master. I want, instead, these 20
> (or more)
> slaves spawned on other machines on the network.
>
> It so happens the mpi.spawn.Rslaves() has an extra argument called
> hosts. Here’s the definition of hosts from the api document:
> “NULL or
> LAM node numbers to specify where R slaves to be spawned.” I have
> no idea what LAM node is, but there is a funciton called
> lamhosts().
> which returns a bit verbose message:
>
> It seems that there is no lamd running on the host
> compute-0-0.local.
>
> This indicates that the LAM/MPI runtime environment is not
> operating.
> The LAM/MPI runtime environment is necessary for the
> "lamnodes" command.
>
> Please run the "lamboot" command the start the LAM/MPI runtime
> environment. See the LAM/MPI documentation for how to invoke
> "lamboot" across multiple machines.
>
> Here’s my question. Is there such command as lamboot in open
> MPI 1.4.3?
> Or am I using a wrong mpi software? In a FAQ I read that
> there are other
> MPI software (FT-mpi, LA-mpi, LAM-mpi), but I had notion that
> open MPI
> is to have functionalities of all. Is this a wrong impression?
>
> Thank you for your help.
>
> Tena Sakai
> tsakai_at_[hidden] <http://tsakai@gallo.ucsf.edu>
>
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>
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-- 
Oracle
Terry D. Dontje | Principal Software Engineer
Developer Tools Engineering | +1.781.442.2631
Oracle *- Performance Technologies*
95 Network Drive, Burlington, MA 01803
Email terry.dontje_at_[hidden] <mailto:terry.dontje_at_[hidden]>



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