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From: rcd@opus.UUCP (Dick Dunn)
Newsgroups: net.arch
Subject: Re: Cray-XMP v/s VP-200
Message-ID: <493@opus.UUCP>
Date: Sat, 19-May-84 03:07:36 EDT
Article-I.D.: opus.493
Posted: Sat May 19 03:07:36 1984
Date-Received: Mon, 21-May-84 03:27:42 EDT
References: <3200004@uicsg.UUCP>
Organization: NBI, Boulder
Lines: 32

>It seems that the most important factor due to which the VP-200
>outperforms the Cray-XMP is the lack of a good Vectorizing Compiler.

This may well be accurate, but it still hurts a bit to read this.  If you
look at the situation from a very global view, you see:
	problems stated in vector notation, with the analytic solutions
	carried out using vector algebra up to the point of getting ready
	to do the calculations, then...

	the calculations are reformulated to get rid of all of the vector
	notation and describe them as explicit iterations, obscuring the
	real intent and effacing the distinction between iterations in
	which the order of calculation matters and those in which it does
	not, following which...

	the description of the calculations is submitted to a compiler
	which has to perform a task just epsilon this side of AI to
	reconstruct the original vector form of the calculations!

No, I'm not so naive as to think that we can just toss out FORTRAN and
replace it with a wonderful language which has notation for vector
operations built into it - but perhaps if such a language (or even a
modification to an existing language) were created, it could gain a
foothold.  The non-vector programming language is clearly a bad bottleneck
between the vector problem and the vector machine.

[On the other hand, these may just be the rantings of a programming-
language nut who's had to work in FORTRAN recently for the first time in
seven years...]
-- 
...A friend of the devil is a friend of mine.		Dick Dunn
{hao,ucbvax,allegra}!nbires!rcd				(303) 444-5710 x3086