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Subject: Re: [OMPI users] Duplicate independent processes
From: Kristian Medri (kmedri_at_[hidden])
Date: 2011-01-06 18:03:07

It appears to be due to not being able to fully remove MPICH2 on machines
that have and aged install. Then Open MPI will not overwrite the remaining
crumbs and is not automagically well configured. I tested this hypothesis on
an additional pair of recent/aged MPICH2 install machines. Currently
reinstalling CentOS 5 on the aged MPICH2 install machine.

The problem is that the same command on the same hardware running the same
code results in 2 communicating processes on the recent MPICH2 install
machine that now has Open MPI on it and 2 individual processes on the aged
MPICH2 install machine that now had Open MPI on it.

-----Original Message-----
From: users-bounces_at_[hidden] [mailto:users-bounces_at_[hidden]] On
Behalf Of Ralph Castain
Sent: January 5, 2011 8:09 PM
To: Open MPI Users
Subject: Re: [OMPI users] Duplicate independent processes

I'm afraid I don't understand your example - are you saying you provide "-np
1" and get two processes instead of 1?

If so, would you please provide info on the type of system where this
happens? I've never seen it with mpich or ompi

On Jan 5, 2011, at 4:57 PM, Kristian Medri wrote:

> Any hints on what to look for to get the second machine to behave without
> duplicate independent processes?
> "mpirun -np 2 ..."
> Provides as expected:
> "Using MPI version 2.1, 2 processes
> .1.
> .2."
> While on another similar machine:
> "Using MPI version 2.2, 1 processes
> .1.
> Using MPI version 2.2, 1 processes
> .1.
> .2.
> .2."
> On both:
> /usr/lib64/openmpi/1.4-gcc/bin/mpirun --version
> Returns:
> mpirun (Open MPI) 1.4
> I looked in the FAQ and searched the list but did not find it yet. When I
> worked with MPICH2 I also had this happen from time to time. I can provide
> additional information should it not be as common here.
> _______________________________________________
> users mailing list
> users_at_[hidden]

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