[MPI3 Fortran] Non-contiguous arrays (was Re: Argument data sizes)

[Supalov, Alexander]

I think, technically, copy-in/out might occur on the subroutine boundary
in this case. This is one of the big problems, especially for the
nonblocking calls like MPI_Isend/Irecv.

-----Original Message-----
From: mpi3-fortran-bounces at lists.mpi-forum.org
[mailto:mpi3-fortran-bounces at lists.mpi-forum.org] On Behalf Of Iain
Bason
Sent: Thursday, September 18, 2008 7:28 PM
To: MPI-3 Fortran working group
Subject: [MPI3 Fortran] Non-contiguous arrays (was Re: Argument data
sizes)


On Sep 18, 2008, at 1:13 PM, Jeff Squyres wrote:

> How else would you do it efficiently for non-contiguous datatypes  
> without a copy (which would be quite Bad for multiple reasons,  
> especially for very large datasets)?  Such issues are certainly not  
> unique to C (even in very large Fortran arrays, particularly if you  
> want to send just a plane from the middle of a 3D array, or  
> somesuch).  As another example of where datatypes are useful: with  
> the Fortran equivalent of C structs, you need to build up a composed  
> datatype to describe the message that you want to send/receive.

Didn't this come up in another thread?  In Fortran, you can use  
assumed shape arrays to pass these sorts of data without copying.  It  
would be nice if MPI could take advantage of that in order to make  
life easier for Fortran programmers.

Iain

_______________________________________________
mpi3-fortran mailing list
mpi3-fortran at lists.mpi-forum.org
http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-fortran
---------------------------------------------------------------------
Intel GmbH
Dornacher Strasse 1
85622 Feldkirchen/Muenchen Germany
Sitz der Gesellschaft: Feldkirchen bei Muenchen
Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer
Registergericht: Muenchen HRB 47456 Ust.-IdNr.
VAT Registration No.: DE129385895
Citibank Frankfurt (BLZ 502 109 00) 600119052

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.