Re: octave-mpi questions

[Martin Siegert]

On Tue, Feb 18, 2003 at 03:09:07PM -0800, JD Cole wrote:

> That would be great if you could test the code I posted earlier, I 
> currently don't have access to a cluster. I have been developing with 
> LAM by running multiple instances on one node.

* The code works with LAM (version 6.5.9)
* the code segfaults in mpi_init immediately with MPICH (version 1.2.5)

It took me a week to figure out why:

- passing NULL to MPI_Init as in MPI_Init(NULL,NULL); is a feature of
  the MPI-2 standard.
- there is (to my knowledge) no MPI implementation that fully implements
  the MPI-2 standard.
- different MPI implementations implement different parts of the MPI-2
  standard
- MPI_Init(NULL,NULL); works in LAM but not in MPICH

I asked the MPICH maintainers about the last point. Here is the answer:

On Fri, Feb 21, 2003 at 09:45:22AM -0600, William Gropp wrote:
> For the ch_p4 device, there isn't any easy patch (the command line
> arguments are used to communicate essential information).  One possibility
> is to use the MPICH2 beta test; MPICH2 is our new implementation of MPI and
> will support all of MPI-2; so far all of MPI-1 and parts of MPI-2 are
> supported (including the use of null args to MPI_Init).  Another choice is
> to use the ch_shmem device of MPICH; that doesn't use command line
> arguments.

My impression is that MPICH2 is really beta (e.g., the F90 interface does
not exist yet).

The only MPI-1 compliant way of calling MPI_Init is
MPI_Init(&argc,&argv);
The question now is: is there a way to provide octave's command line
arguments to the mpi_init module?

Martin

========================================================================
Martin Siegert
Academic Computing Services                        phone: (604) 291-4691
Simon Fraser University                            fax:   (604) 291-4242
Burnaby, British Columbia                          email: address@hidden
Canada  V5A 1S6
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