[mpich-discuss] Help: MPICH for a beginner

[Pavan Balaji]

On 07/13/2010 11:47 AM, Michele Rosso wrote:
> Thanks Pavan for your reply.
> I followed the instructions.
> At first I got mpd started, then, after I compiled my code through
> mpif90, I run the executable by using the command:
> 
> mpiexec -np 4 ./filename
> 
> This command works properly since I got the results I was expecting, but
> I have the feeling that it is still running the serial version of the
> code, since in the output (shell) there are only the output lines of the
> node 0. Any idea about that?

Are you sure your program is not doing something like:

if (my_rank is 0)
    print(...)

You can try some other program, maybe "ls" or "hostname":

% mpiexec -np 4 hostname

% mpiexec -np 4 ls

This should give you a separate output for each process.

  -- Pavan

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji