Very Computer

I've been playing around with the MPICH implementation recently.
I found out that the MPI_GET_SOURCE, MPI_GET_TAG and MPI_GET_COUNT
routines are not implemented. Is there a particular reason for that?
(I did the implementation by my own and it took me 5 minutes or 23 lines
of FORTRAN code(without error handling).)

        Bernd

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Bernd Wender
University of Vienna                        
Institute for Software Technology and Parallel Systems              

http://www.par.univie.ac.at/htbin/wender.home
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at night and ponders the existence of DoG?

The official MPI specification (May 94) only specifies a MPI_GET_COUNT,
which is in fact implemented in MPICH (file src/pt2pt/getcount.c in the
MPICH-1.05 distribution).

The standard explains how to extract the SOURCE and TAG fields from
the "status" parameter (pp. 20-21):

 C:       use "status.MPI_SOURCE" or "status.MPI_TAG"
 FORTRAN: use "status(MPI_SOURCE)" or "status(MPI_TAG)"

joep.
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joep vesseur

: I've been playing around with the MPICH implementation recently.
: I found out that the MPI_GET_SOURCE, MPI_GET_TAG and MPI_GET_COUNT
: routines are not implemented. Is there a particular reason for that?
: (I did the implementation by my own and it took me 5 minutes or 23 lines
: of FORTRAN code(without error handling).)

:       Bernd

  MPI_GET_SOURCE and MPI_GET_TAG were done away with in the final version
  of the MPI document.  From the standard document dated May 5th,
  Section 3.2.5 (http:////www.mcs.anl.gov/mpi/mpi-report/node34.html#Node34):

      In C, status is a structure that contains two fields named
      MPI_SOURCE and MPI_TAG, and the structure may contain
      additional fields. Thus, status.MPI_SOURCE and status.
      MPI_TAG contain the source and tag, respectively, of the
      received message.

      In Fortran, status is an array of INTEGERs of size
      MPI_STATUS_SIZE. The two constants MPI_SOURCE and MPI_TAG
      are the indices of the entries that store the source and
      tag fields. Thus status(MPI_SOURCE) and status(MPI_TAG)
      contain, respectively, the source and the tag of the
      received message.

  The MPI_GET_COUNT function is present in the MPICH implementation.

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