Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] RFC: add support for large counts using derived datatypes
From: Jeff Squyres (jsquyres) (jsquyres_at_[hidden])
Date: 2013-07-16 17:07:21


On Jul 16, 2013, at 5:03 PM, George Bosilca <bosilca_at_[hidden]> wrote:

>> Yes, it can -- it has to be the largest integer type (i.e., it even has to be able to handle an MPI_Offset).
>
> Technicalities! In the entire standard MPI_Offset is only used to access files, not to build datatypes. As such there is no way to have the extent of an datatype bigger than MPI_Aint.

Datatypes are used in FILE_SET_VIEW.

-- 
Jeff Squyres
jsquyres_at_[hidden]
For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/