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Subject: Re: [OMPI devel] RFC: add support for large counts using derived datatypes
From: Jeff Squyres (jsquyres) (jsquyres_at_[hidden])
Date: 2013-07-16 16:29:40


On Jul 16, 2013, at 4:22 PM, George Bosilca <bosilca_at_[hidden]> wrote:

> Btw, I have a question to you fellow MPI Forum attendees. I just can't remember why the MPI forum felt there was a need for the MPI_Type_get[_true]_extent_x? MPI_Count can't be bigger than MPI_Aint,

Yes, it can -- it has to be the largest integer type (i.e., it even has to be able to handle an MPI_Offset).

> so I don't see what is the benefit of extending the MPI_Type_get_true_extent(MPI_Datatype, MPI_Aint*, MPI_Aint*) and MPI_Type_get_extent(MPI_Datatype, MPI_Aint*, MPI_Aint*) with the corresponding _X versions?

-- 
Jeff Squyres
jsquyres_at_[hidden]
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