(j3.2006) (SC22WG5.3611) Preparing for the Tokyo meeting
Lawrie Schonfelder
j.l.schonfelder
Fri Oct 31 17:07:28 EDT 2008
I will refrain, I hope from ranting!
I will nevertheless continue in the firmly held belief that even if co-arrays are "superbly
wonderful" for expressing parallelism on a number of popular architectures, they are not universally
"the answer to a maiden's prayer" on all architectures. They quite manifestly do not make a "knats
testicles" improvement in the ease of expressing <emf>any</emf> algorithm on a uniprocessor system,
and I suspect there are a number of other potential architectures on which co-arrays will be less
than helpful.
It is for this reason that I will continue to support the definition of co-arrays as an optional
part of Fortran but will continue to vote against any standard that insists on including them as a
part or the core definition of the language.
I do not think John's "compromise" sensible or useful, a compromise too far!
Co-arrays as a part-N or as a TR are acceptable, possibly even desirable, but absolutely
unacceptable as an integral part or the core language.
--
Lawrie Schonfelder
Wirral, UK
> -----Original Message-----
> From: j3-bounces at j3-fortran.org [mailto:j3-bounces at j3-fortran.org]On
> Behalf Of John Wallin
> Sent: 31 October 2008 17:08
> To: longb at cray.com; fortran standards email list for J3
> Cc: John.Reid at stfc.ac.uk
> Subject: Re: (j3.2006) (SC22WG5.3611) Preparing for the Tokyo meeting
>
>
> Hi all,
>
> I haven't chimed on this, but I have to agree with Bill. We rehashed this for two days
> at the last the WG5 meeting, and reached a compromise that was suggested by Alex.
> Specifically, that the coarray's would be reduced in scope AND they would be included in
> part I. We (J3) reduced the scope, as per the agreement. From the agreement and the
> discussions, I certainly expected this discussion was over and that this decision had
> already been made.
>
> -John Wallin
>
> From: Bill Long <longb at cray.com>
> Date: Friday, October 31, 2008 12:24 pm
> Subject: Re: (j3.2006) (SC22WG5.3611) Preparing for the Tokyo meeting
>
> >
> >
> > John Reid wrote:
> > > As I see it, the most difficult problems that we need to face in
> > Tokyo are:
> > >
> > > 1. Whether coarrays should be integrated in Part 1.
> > >
> > > 2. Whether to allow coarrays to be volatile.
> > >
> > > I have a suggestion re 1, which no-one seems to like (does this
> > mean it might be
> > > suitable as a compromise?!):
> >
> > I reject the idea that additional compromise is needed. We've
> > voted
> > over and over on this topic and made a massive compromise at the
> > last
> > WG5 meeting to get consensus. I've read through the new UK papers,
> > and
> > there is no new technical information there to suggest need for
> > substantial changes. There will always be a few who will never
> > give up
> > their argument that coarrays should not be in the standard. They
> > need
> > to accept that they have lost and discontinue their rants.
> >
> >
> > > follow the precedent of Fortran 77 where there was
> > > a full language and a subset language.
> >
> > You are right that no-one will like this idea. It's a bad idea. It
> > goes
> > directly against the idea of "standard" (singular). It sends a
> > message
> > that we "didn't really mean the coarray stuff", and is no different
> > from
> > the Part 2 proposal that was rejected. For implementors, this
> > would
> > offer no meaningful advantage over the option of supporting just 1
> > image, which is already allowed with the current, unified text.
> >
> > Cheers,
> > Bill
> >
> > > One caught on and everyone talking of
> > > Fortran 77 now means that one. It was done with facing pages
> > specifying the two
> > > levels, which would not be practical for Fortran 2008. I think we
> > would need to
> > > concatenate the two, which should not a problem in these days of
> > electronic
> > > publication. Which of the two is developed further (or neither or
> > both) would
> > > depend on their success in the field. If it is just one, that
> > will be what
> > > future generations will regard as Fortran 2008.
> > >
> > > My suggestion re 2 is in N1752.
> > >
> > > See you in Tokyo.
> > >
> > > John.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > J3 mailing list
> > > J3 at j3-fortran.org
> > > http://j3-fortran.org/mailman/listinfo/j3
> > >
> >
> > --
> > Bill Long longb at cray.com
> > Fortran Technical Support & voice: 651-605-9024
> > Bioinformatics Software Development fax: 651-605-9142
> > Cray Inc., 1340 Mendota Heights Rd., Mendota Heights, MN, 55120
> >
> >
> >
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> > J3 at j3-fortran.org
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> >
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