[Beowulf] lamexec vs mpirun

Glen Beane Glen.Beane at jax.org
Thu Dec 3 11:31:58 PST 2009

On 12/3/09 2:22 PM, "Glen Beane" <glen.beane at jax.org> wrote:

On 12/3/09 1:16 AM, "christian suhendra" <christiansuhendra at gmail.com> wrote:

hello guys i've buliding a cluster system with mpich-1.2.7p1,when i test my machine it work..but when i run the mpirun it doesn't work ini cluster...but its running
and i got this error
It seems that [at least] one of the processes that was started with
mpirun did not invoke MPI_INIT before quitting (it is possible that
more than one process did not invoke MPI_INIT -- mpirun was only
notified of the first one, which was on node n0).

mpirun can *only* be used with MPI programs (i.e., programs that
invoke MPI_INIT and MPI_FINALIZE).  You can use the "lamexec" program
to run non-MPI programs over the lambooted nodes.

and then i try to run lamexec it work..
 i wanna ask you guys the different between of lamexec and mpirun
thank you for your advice

You are not using mpich,  you are using LAM-MPI. LAM uses daemons that must be running on all of the nodes before mpirun can launch the MPI executables.   The lamexec command essentially does a "lamboot" and "mpirun" in a single command.  By the way, LAM is deprecated, and its users are encouraged to switch to OpenMPI.  If you were intending to use mpich and have it installed on your system LAM is being found first in your path and not mpich.

Actually, I take this back - lamexec is not like lamboot and mpirun in one,  for some reason I had LAM's mpiexec command on my mind, which if I remember right is equivalent to  lamboot + mpirun  (It has been a while).  lamexec is like a distributed shell that launches non-mpi programs on nodes running the LAM daemon (lamd).  but my main point still stands,  you aren't using mpich even if you think you are.

Glen L. Beane
Software Engineer
The Jackson Laboratory
Phone (207) 288-6153

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