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Subject: Re: [OMPI users] problem with MPI datatypes not defined as constants in OpenMPI
From: Jeff Squyres (jsquyres) (jsquyres_at_[hidden])
Date: 2013-01-08 17:51:20


On Jan 8, 2013, at 5:49 PM, Crni Gorac <cgorac_at_[hidden]>
 wrote:

> Most MPI implementations (MPICH, Intel MPI) are defining MPI datatypes (MPI_INT, MPI_FLOAT etc.) as constants; in OpenMPI, these are practically pointers to corresponding internal structures (for example MPI_FLOAT is defined as pointer to mpi_float structure, etc.). In trying to employ some C++ templates to automate mapping between C types and MPI datatypes (code provided below), I've encountered a problem with this, so I'm wondering - is OpenMPI approach in accordance with MPI standard?

Yes.

The MPI spec doesn't specify the back-end types of MPI handles. The two popular implementation choices are integers (usually C int's, such as with MPICH) and pointers (like Open MPI).

-- 
Jeff Squyres
jsquyres_at_[hidden]
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