(j3.2006) [MPI3 Fortran] Feedback from Fortran J3 meeting
Wed May 28 14:42:00 EDT 2008
Keith Bierman wrote:
> On May 28, 2008, at 10:56 AM 5/28/, Craig Rasmussen wrote:
>> I wonder how C does this? What are the rules for code motion in C?
>> I'll ask around.
> Highly prescribed by their Standard. Fortran's advantage has been
> much more latitude to the optimizer.
> While the Committee has always preferred to design more generic
> solutions, MPI is an important special case ... it might just be a
> lot easier to have an optional part of the Standard which puts MPI in
> as special modules ...
I see this as very backward looking. We've done a lot of work to
produce a native parallel programming model within Fortran that lacks
these problems that MPI has. Producing a whole optional part of the
standard just to accommodate a legacy library that one would expect,
over time, to fall by the wayside, seems like a bad idea on multiple fronts.
> then it's up to the implementors to "do it
If vendors are currently getting it "wrong", how is it possible that so
many people are using MPI today? I'm yet to be convinced there is a
> rather than trying to describe all the right behaviors in a
> processor and OS agnostic manner consistent with the "abstract
> Fortran machine" (I know, we don't have those words, but we have the
> concept ;>).
Bill Long longb at cray.com
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