Re: [Mpi-22] Another MPI-2.2 attribute ambiguity?
On May 19, 2009, at 8:55 PM, Jeff Squyres (jsquyres) wrote:
So then you're in favor of #1 from my original post, right?
To be even more clear: - Open MPI's upcoming v1.3.3 currently does #1 - Platform (Scali) MPI does #1 - HP MPI does #2 - I *think* MPICH2 is doing #1 (Bill's text can be interpreted 2 ways, but we already discussed that it's not valid to keep the address of the value passed through MPI_*_CREATE_KEYVAL) - Alexander said that Intel MPI does the same thing as Bill's original reply, but I'm not sure what that means (because Bill's original reply was about C) I don't know what IBM MPI, NEC MPI, or others do (I assume MS MPI and MVAPICH do the same thing as MPICH2).
On May 19, 2009, at 4:39 PM, William Gropp wrote:
Silly me, I missed that.
In Fortran (particularly thinking in terms of Fortran 77, since that was the original design), the Fortran callback should be able to do things like increment the "extra data" - i.e., if the extra data is a counter, the Fortran callback should be able to increment it. Since Fortran 77 has no pointers (and pointers in Fortran 90 aren't the same as addresses), having an address is worthless in a Fortran 77 program. So if the MPI implementation stores the address of the extra data and passes that to the call back (by value, so Fortran sees the address of the extra data), users should get what they expect in Fortran.
Bill
On May 19, 2009, at 12:22 PM, Iain Bason wrote:
On May 19, 2009, at 1:16 PM, William Gropp wrote:
MPICH2 passes the value of the extra_state that was saved in the internal storage to the callback routine, which is case 2 (the
copy
is implicit as the value is passed to the routine and C semantics ensures that the value isn't changed).
But this is the Fortran interface, not the C interface.
Iain
William Gropp Deputy Director for Research Institute for Advanced Computing Applications and Technologies Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign
_______________________________________________ mpi-22 mailing list mpi-22_at_[hidden] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-22
-- Jeff Squyres Cisco Systems
_______________________________________________ mpi-22 mailing list mpi-22_at_[hidden] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi-22
-- Jeff Squyres Cisco Systems
participants (1)
-
unknown＠example.com