Sounds to me like you are getting a heavy dose of version contamination. I can't see any way for a single instance of mpirun to launch two procs given an input line of
mpirun -np 1 my_prog There isn't any way OMPI can (or would) uninstall a prior installation of MPICH2, or any other MPI for that matter. Many users maintain both on their systems without problem by simply installing them to different locations and letting $PATH and friends keep things separated. On Jan 6, 2011, at 4:03 PM, Kristian Medri wrote: > 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-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] 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 >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
