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Thread: Re: LAM: Matrix mult / Inversion in Octave with MPITB




Re: LAM: Matrix mult / Inversion in Octave with MPITB
country flaguser name
Spain
2007-10-11 11:47:24
Mike Roberts  wrote:
> Hi.
> I have a working non parallel code in Octave that I am
trying to set 
> up to work in parallel.  Really what I need is to run a
few pieces of 
> the code in Parallel, one big matrix multiplication and
one big matrix 
> inversion (actually it uses the backslash operator). 
Sorry for the confussion. MPITB is not a tool for
automatically 
parallelizing Octave matrix operations. It's an Octave
interface to MPI. 
I would be willling to correct any sentence in MPITB web or
help files 
that could be misleading prospective users to make them
believe MPITB 
will automatically parallelize their Octave code.

> I see many of the sample mpitb octave codes seem to
split up the 
> processes manually, sending them to different nodes;
Indeed. All MPITB examples have to do so. There isn't any
form of 
implicit parallelism in MPITB, all must be explicitly
parallelized.

> I am not sure how I would do that here.  Any good info
on how to do 
> this would be great, perhaps even a nice reference on
using mpitb with 
> octave would also be great.  I am very new to using
mpi, so I a might 
> be missing something basic.

I'm not sure you can benefit from MPITB. Perhaps ScaLAPACK
and Octave 
DLDs are more appropriate tools for your target.
http:
//wiki.octave.org/wiki.pl?CategoryExternal
h
ttp://www.netlib.org/scalapack/scalapack_home.html

In any case, in order to use MPITB you must choose exactly
which code is 
to be run over exactly which data on each or your cluster
nodes. If you 
can't (or don't want to) do the choice, your tool is not
MPITB.

Send me a personal e-mail if you want me to modify any
sentence in MPITB 
web or help file. Again, sorry for the confussion. Hope it
didn't make 
you lose much time.

-javier
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