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Subject: Re: [OMPI users] mpirun -np 4 hello_world; on a eight processor shared memory machine produces wrong output
From: Pankatz, Klaus (klaus.pankatz_at_[hidden])
Date: 2010-04-23 08:24:55


Yes, I did that.

It ist basically the same problem with a Fortran version of this little program. With that I used the mpif90 command of openMPI.
________________________________________
Von: users-bounces_at_[hidden] [users-bounces_at_[hidden]] im Auftrag von Reuti [reuti_at_[hidden]]
Gesendet: Freitag, 23. April 2010 14:15
An: Open MPI Users
Betreff: Re: [OMPI users] mpirun -np 4 hello_world; on a eight processor shared memory machine produces wrong output

Hi,

Am 23.04.2010 um 14:06 schrieb Pankatz, Klaus:

> Hi all,
>
> there's a problem with openMPI on my machine. When I simply try to run this little hello_world-program on multiple processors, the output isn't as expected:
> *****
> C code:
> #include <mpi.h>
> #include <stdio.h>
> #include <unistd.h>
> int main(int argc, char **argv)
> {
> int size,rank;
> char hostname[50];
> MPI_Init(&argc,&argv);
> MPI_Comm_rank(MPI_COMM_WORLD, &rank); //Who am I?
> MPI_Comm_size(MPI_COMM_WORLD, &size); //How many processes?
> gethostname (hostname, 50);
> printf ("Hello World! I'm number %2d of %2d running on host %s\n",
> rank, size, hostname);
> MPI_Finalize();
> return 0;
> }
> ****
>
> Command: mpirun -np 4 a.out

the mpirun (better, use: mpiexec) is the one from the Open MPI, and you also used its version mpicc to compile the program?

-- Reuti

> Output:
> Hello World! I'm number 0 of 1 running on host marvin
> Hello World! I'm number 0 of 1 running on host marvin
> Hello World! I'm number 0 of 1 running on host marvin
> Hello World! I'm number 0 of 1 running on host marvin
>
> It should be more or less:
> Hello World! I'm number 1 of 4 running on host marvin
> Hello World! I'm number 2 of 4 running on host marvin
> ....
>
> OpenMPI-version 1.4.1 compiled with Lahey Fortran 95 (lf95).
> OpenMPI was compiled "out of the box" only changing to the Lahey compiler with a setenv $FC lf95
>
> The System: Linux marvin 2.6.27.6-1 #1 SMP Sat Nov 15 20:19:04 CET 2008 x86_64 GNU/Linux
>
> Compiler: Lahey/Fujitsu Linux64 Fortran Compiler Release L8.10a
>
> Thanks very much!
> Klaus
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users

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