I cannot say for sure, but this is symptomatic of using the wrong
mpirun command -- i.e., an mpirun command that belongs to a different
MPI implementation. Specifically, if you compile an application with
LAM and then run it with another MPI implementation's mpirun, the LAM
processes will likely think that they are singletons (i.e., the same
as if you had not used mpirun and simply invoked "./a.out"), and
therefore have an MPI_COMM_WORLD size of 1.
Can you verify that you're invoking LAM's mpirun command?
On Feb 13, 2006, at 5:36 PM, rtichy_at_[hidden] wrote:
> I am trying to run my mpi ap using lam on my home machine. The
> problem is the application uses the rank returned by
> 'MPI::COMM_WORLD.Get_rank()' to figure out who is who and
> distribute information accordingly
>
> The problem is that on my machine, when running the command:
>
> mpirun -np 4 myapp myargs
>
> ... all processes return the same rank so they all think they are
> the master and my app crashes. Am I missing something naive or is
> there a way to force lam to give each process a different rank even
> when running on a single processor?
>
> I am really a little stuck on this one and after 2 odd hours of
> trying to find a relevant post I just gave up. Can anyone suggest
> something?
--
{+} Jeff Squyres
{+} The Open MPI Project
{+} http://www.open-mpi.org/
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