[Mpi-forum] MPI_Alltoall from multiple buffers

Michael Raymond mraymond at sgi.com
Mon Jun 28 07:13:29 CDT 2010

  While we're on the topic of MPI types, has a version of MPI_Alltoall
that does not assume that all data comes from the same large buffer ever
been discussed?  I'm speaking of something like:

MPI_Alltoallx(void ** sendbuf, ..., void ** recvbuf,...)

  It is sometimes the case where I want to send many different objects
to different endpoints.  This is certainly doable with many calls to
MPI_Type_create_struct() offset from MPI_BOTTOM using MPI_Alltoallw()
but it's annoying and adds overhead.

Michael A. Raymond
Message Passing Toolkit Team
Silicon Graphics Inc
(651) 683-3434

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