Well, a remark on that: What about providing an ISO_C_BINDING based interface? MPI is not a game and programmers doing MPI are usually quite good and capable of handling the basic type checking themselfs ...

The current MPI-2 F90 bindings are un-implementable because they require almost 7 *million* interface functions: with 15 intrinsic Fortran types, each with 7 possible dimensions, the current F90 interface *requires*:

- 50 MPI functions with one choice buffer: 15 * 7 * 50 = 5,250 functions - 25 MPI functions with two choice buffers: (15 * 7 * 25)^2 = 6.8M functions - ...and a few hundred more MPI functions with no choice buffers

This is clearly broken.

An MPI-2.1-worthy solution could be to add a global statement saying that MPI functions with two choice buffers are explicitly not included in the F90 bindings. F90 MPI applications can transparently fall back to the F77 bindings (although they won't get the strong type checking, etc.). This idea therefore fits the requirement of not breaking any existing MPI codes.

Specifically: if we remove the requirement to provide all MPI functions with two choice buffers, 5,000+ F90 interface functions is [a pain but] implementable. I doubt that any current MPI implementation provides more than the no-choice-buffers plus one- choice-buffer functions anyway...

If this seems like a good idea, I can write a proper proposal for it. Comments?

-- Jeff Squyres Cisco Systems

_______________________________________________ mpi-21 mailing list mpi-21_at_[hidden] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-21

-- \\\\\\ (-0^0-) --------------------------oOO--(_)--OOo----------------------------- Luis Kornblueh Tel. : +49-40-41173289 Max-Planck-Institute for Meteorology Fax. : +49-40-41173298 Bundesstr. 53 D-20146 Hamburg Email: luis.kornblueh_at_[hidden] Federal Republic of Germany