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Subject: Re: [OMPI users] MPI_Allreduce on local machine
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2010-08-16 12:08:59

On Aug 10, 2010, at 3:59 PM, Gus Correa wrote:

> Thank you for opening a ticket and taking care of this.

Sorry -- I missed your inline questions when I first read this mail...

> > That being said, we didn't previously find any correctness
> > issues with using an alignment of 1.
> Does it affect only the information
> provided by ompi_info, as Martin Siegert suggested?

> Or does it really affect the actual alignment of
> MPI types when OpenMPI is compiled with Intel,
> as Martin, Ake Sandgren, Hugo Gagnon, and myself
> thought it might?

It affects both: I do see the size and alignment of double precisions (as determined by configure) used in the OMPI datatype engine (and real8, etc.). We had a copy-n-paste error in ompi_info such that some Fortran types were displaying the wrong sizes / alignments.

Jeff Squyres
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