Re: Octave Forge MPI package on Sungrid cluster

[c.]

On 24 Apr 2014, at 15:00, Timo <address@hidden> wrote:

> Hello out there,
> 
> I am trying to use Octave MPI functionalities for some parallel
> computations. I have my codes running on my desktop PC (Ubuntu 13.10,
> Open MPI version 1.4.5, Octave 3.6.4 and openmpi_ext 1.1.0).
> 
> Now I got the kind system administrator of a Sungrid cluster that I have
> access to to install the MPI package and Octave on the cluster (Open MPI
> 1.6.5, Octave 3.8.1, openmpi_ext  1.2.0).

there is no such thing as "openmpi_ext 1.2.0" the package changed
name to just "mpi", can you try typing:

pkg list

to check what you actually have installed?

> Somehow, I do not get my codes running on the cluster. I tried the
> "helloworld.m" that comes with the mpi package of Octave. On my PC is
> works perfect, returning me the expected output from all processes
> "Greetings from process: X!". On the cluster I do not get any output,
> also no error message.
> 
> Doing some debugging, I figured out that every process I call has node=0
> as a return from "MPI_Comm_rank()". The rank should of course be zero
> only for the master call. So the program executes fine, but never enters
> my slave tasks that are defined for nodes unequal zero...

How exactly did you get to this conclusion?
How did you start the different processes? 
How did you check the value of MPI_Comm_rank()?
does your cluster require you to run jobs via a scheduler?

Can you just post a simple script that demonstrates this 
behaviour, the commands you use to run it and the output you get when you run 
it?

> I do not know how to debug further, also checking from google did not
> bring me anywhere.
> Any suggestions?? Is there people out there using the MPI extension on
> grip computers??

The fact that "MPI_Comm_rank()" always returns 0 sounds very strange
what do you get if you run the attached C program doing

mpicc helloworld.c -o helloworld
mpiexec -np 2 ./helloworld

? what do you get if you run 

mpiexec -np 2 octave -q --eval "pkg load mpi; more off; helloworld"

?


> Thanks in advance
> Timo


c.

helloworld.c
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