From: Rolf Rabenseifner <Rabenseifner@XXXXXXXXXXXXXXXXXXXX>
Subject: BUG in MPI-2 Alltoallw
To: mpi-core@XXXXXXXXXXX
Date: Wed, 29 Nov 2000 18:14:21 +0100 (CET)
Cc: edgar.gabriel@XXXXXXXXXXXXXXXXXXXX
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Hello,

a collegue has found a possible bug in the MPI-2 language bindings
of MPI_Alltoallw.

Page 165, we defined the byte-displacements as int (in C) and INTEGER
(in Fortran).

But, this should be MPI_Aint and INTEGER(INTEGER=MPI_ADDRESS_KIND) 
because the displacements are byte-displacements
(and not datatype-displacements as in MPI_Alltoallv).

Pros and Cons?

Pro: One major reason for MPI_Alltoallw was, to allow different 
     buffers via MPI_BOTTOM. Correct usage of MPI_BOTTOM
     requires address-length displacements.

Con: This errata would change the APIs.

Best regards
Rolf 


Dr. Rolf Rabenseifner                      High Performance Computing
Parallel Computing                         Center Stuttgart    (HLRS)
Rechenzentrum Universitaet Stuttgart (RUS) Phone:    ++49 711 6855530
Allmandring 30                             FAX:      ++49 711 6787626
D-70550 Stuttgart                   rabenseifner@XXXXXXXXXXXXXXXXXXXX
Germany                        http://www.hlrs.de/people/rabenseifner