From octave-maintainers-request at bevo dot che dot wisc dot edu Thu Nov 21 11:04:35 2002
Subject: Re: Patching Octave-MPI
From: Paul Kienzle <pkienzle at jazz dot ncnr dot nist dot gov>
To: octave-maintainers at bevo dot che dot wisc dot edu
Date: Thu, 21 Nov 2002 12:04:34 -0500

So maybe we need the equivalent of gcc's -Wl,"blah", so that octave
m-files/octave-files can receive parameters from the command line
that octave ignores?  From there we can build a pretend original
argc/argv pair to hand to MPI.

Paul Kienzle
pkienzle at users dot sf dot net

On Thu, Nov 21, 2002 at 11:51:19AM -0500, Andy Jacobson wrote:
> >>>>> "Paul" == Paul Kienzle <pkienzle at jazz dot ncnr dot nist dot gov> writes:
> 
>     Paul> There are a variety of approaches to parallelism which have
>     Paul> been done in matlab m-files and mex-files.  E.g.,
> 
> Alex Verstak raised an interesting point last year: he said that the
> MPI standard requires that MPI_Init() be fed the *original* argv and
> argc.  (Yes, it is arguably a silly requirement.)  With at least MPICH
> apparently, MPI_Init() would not work from a .oct file.  See:
> 
> http://www.octave.org/mailing-lists/help-octave/2001/141
> 
> Later however, Alex apparently did get it running:
> 
> http://www.octave.org/mailing-lists/help-octave/2001/218
> 
> So perhaps a .oct solution will work.
> 
> Note however that the parallelized Matlab solutions all are guided by
> two facts: (1) they cannot modify the source code so the
> parallelization has to work via .mex/.m files, and (2) due to the cost
> of multiple Matlab licenses, there may be implicit assumptions about
> how many instances are running in a given MPI application.  There may
> be hidden performance issues.
> 
> It should a pretty trivial matter to determine whether or not the user
> wants a parallel or traditional application when she starts octave.
> Perhaps something as simple as "octave --mpi-server" or "octave
> --mpi-client".  Then we call MPI_Init() (and later MPI_Finalize()) as
> appropriate.  That is just about all that is required from the main
> code; the rest could naturally be moved to .oct.
> 
>         Regards,
> 
>                Andy
> 
> -- 
> Andy Jacobson
> 
> arj at gfdl dot gov
> 
> Program in Atmospheric and Oceanic Sciences
> Sayre Hall, Forrestal Campus
> Princeton University
> PO Box CN710 Princeton, NJ 08544-0710 USA
> 
> Tel: 609/258-5260  Fax: 609/258-2850
>