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From: Karsten Bolding (karsten_at_[hidden])
Date: 2007-10-31 13:45:39

On Wed, Oct 31, 2007 at 09:27:48 -0700, Jeff Squyres wrote:
> I think you should use the MPI_PROC_NULL constant itself, not a hard-
> coded value of -1.

the value -1 was in the neighbor specification file.

> Specifically: the value of MPI_PROC_NULL is not set in the MPI
> standard -- so implementations are free to choose whatever value they
> want. In Open MPI, MPI_PROC_NULL is -2. So using -1 is an illegal
> destination, and you therefore get the error that you described.

now I make a check if the neighbor is -1 - then set to MPI_PROC_NULL -
and voila everything is OK.


In a different thread I read about a performance penalty in OpenMPI if
more than one MPI-process is running on one processor/core - is that
correct? I mean having max-slots>4 on a quad-core machine.


Karsten Bolding                    Bolding & Burchard Hydrodynamics
Strandgyden 25                     Phone: +45 64422058
DK-5466 Asperup                    Fax:   +45 64422068
Denmark                            Email: karsten_at_[hidden],5466,11,3