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From: turner@uicsrd.UUCP
Newsgroups: comp.arch
Subject: Re: Hypercubes (place in life)
Message-ID: <43700009@uicsrd>
Date: Sun, 1-Mar-87 00:36:00 EST
Article-I.D.: uicsrd.43700009
Posted: Sun Mar  1 00:36:00 1987
Date-Received: Tue, 3-Mar-87 19:57:12 EST
References: <362@ames.UUCP>
Lines: 34
Nf-ID: #R:ames.UUCP:362:uicsrd:43700009:000:1840
Nf-From: uicsrd.CSRD.UIUC.EDU!turner    Feb 28 23:36:00 1987


() Written  by miner@ulowell.cs.ulowell.edu in uicsrd:comp.arch 
()In article <362@ames.UUCP> eugene@pioneer.UUCP (Eugene Miya N.) writes:
()>Don't expect to take you dusty deck C or Fortran and have it automatically
()>parallelize it (when it does, we will have achieved true AI 8-).
()>--eugene miya
()>  NASA Ames Research Center
()
()The Alliant (a supermini parallel/vector machine made in MA) has a
()decent parallelizing FORTRAN compiler, and they are working on a C.
()Many of the companies coming out with parallel computer systems are
()doing parallelizing FORTRAN as the first language.  Still not the best
()way to express things, but it allows you to port code.  And even with
()compilers like Alliant's it is still good to go through the code and
()modify loops to remove dependencies between variables etc, it helps
()the compiler perform better.
()Rich Miner !ulowell!miner Cntr for Productivity Enhancement

There is a BIG difference between parallelizing for a machine like the
Alliant, with lots of nice loop-type synchronization built in (not to
mention a shared memory architecture), and automatic parallelization
for a HYPERCUBE.  When, and if, we do achieve that it will involve far
more than the simple kinds of data dependence analysis that is the
basis for the || compilers that are beginning to appear commercially.
If the differences are not bloody obvious, mail me and I'll be more
than happy to share the troubles I've seen in writing for the iPSC,
compared to an FX/8 its a totally different ball game.  Fun, but tough.
---------------------------------------------------------------------------
 Steve Turner (on the Si prairie  - UIUC CSRD)

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