[Mpi-forum] Discussion points from the MPI-<next> discussion today

N.M. Maclaren nmm1 at cam.ac.uk
Sat Sep 22 05:24:47 CDT 2012

On Sep 22 2012, Supalov, Alexander wrote:
>Indeed. The road goes on and on. :)

Yes, but the real questions are:

    a) Is this a sensible road to follow, or does it lead to perdition?
It isn't always a good way to provide functionality - vide Fortran versus
C++, where they are comparably flexible, but the latter is 3-5 times as
large as the former.

    b) Would it be better to establish defined halting places, for the
majority of users and a very large number of implementors who do not want
to follow the path to the end?  For the majority of uses, one can achieve
99% of the functionality for 10% of the implementation effort.

I haven't investigated implementations in any depth recently, but recent
quick looks confirms that quite a few MPI features are NOT available in
all of the major ones.  I know that is true for heterogeneous systems,
and the more extreme threading options, but there are quite a few other
areas where I should be flabberghasted if it were not.  And, of course,
at least some of the almost-unused features don't actually work quite
right, but don't get fixed because nobody gives a damn ....

Nick Maclaren.

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