[Mpi-comments] Error in MPI_Neighbor_alltoallw example?

[Rajeev Thakur]

Yes, see https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/420

Rajeev


On Dec 5, 2014, at 9:41 AM, Timothy Brown <Timothy.Brown-1 at Colorado.EDU> wrote:

> Hello.
> 
> I was trying to use MPI_Neighbor_alltoallw() and was following the example on page 333 of the MPI-3.0 standard. However I believe the send and receive counts are incorrect. Lines 21 to 25:
> 
> DO i=1,num_neigh
>  sndcounts(i) = 100
>  rcvcounts(i) = 100
>  rcvtypes(i)  = sndtypes(i)
> END DO
> 
> Since the send/receive counts for 1 and 2 are vectors types of length 100, we should be sending/receiving only 1 type/element. As follows:
> 
> sndcounts(1) = 1
> sndcounts(2) = 1
> sndcounts(3) = 100
> sndcounts(4) = 100
> 
> rcvcounts = sndcounts
> 
> Indeed if I compile the example as per the standard, I get data corruption.
> 
> I couldn't find this in the errata published on May 14, 2014.  However if it is a known mistake please ignore my comment. 
> 
> Regards
> Timothy Brown
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