Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2005-10-31 22:33:06

On Oct 28, 2005, at 3:08 PM, Jeff Squyres wrote:

> 1. I'm concerned about the MPI_Reduce error -- that one shouldn't be
> happening at all. We have table lookups for the MPI_Op/MPI_Datatype
> combinations that are supposed to work; the fact that you're getting
> this error means that HPCC is using a combination that falls outside
> the pairs that are defined in the MPI standard. Sigh. But it's HPCC,
> so we should support it ;-).

I'll eat crow on this one -- double checking the HPCC code, it looks
like they are doing reductions on MPI_LONG_LONG_INT, which is perfectly
legal (MPI_LONG_LONG_INT is not specifically mentioned in the
collectives section in MPI-1, but it's one of the "optional" C
datatypes, and falls within the spirit of the definition of "C integer"
in the collectives section). Despite having implementations for all
the relevant reductions in Open MPI, I forgot to add MPI_LONG_LONG_INT
into some MPI_Op cross-reference datatype tables, so MPI_Reduce didn't
think that those combinations were valid. Doh!

I just committed the fix for this on the trunk; everyone's asleep right
now, but I'll get a review of this code and get it committed on the 1.0
branch tomorrow. :-)

{+} Jeff Squyres
{+} The Open MPI Project