Newsgroups: comp.arch
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: IEEE floating point
Message-ID: <1991May24.173747.1483@zoo.toronto.edu>
Date: Fri, 24 May 1991 17:37:47 GMT
References: <9105240158.AA02761@ucbvax.Berkeley.EDU>
Organization: U of Toronto Zoology

In article <9105240158.AA02761@ucbvax.Berkeley.EDU> jbs@WATSON.IBM.COM writes:
>         As to wrong answers, wrong answers are generally caused by
>users not knowing what they are doing.  Users who do know what they are
>doing don't need IEEE arithmetic to get right answers, users who don't
>know what they are doing will have no problems getting wrong answers
>using IEEE arithmetic.

Unfortunately, numerical computing is too useful and too widespread to
remain the plaything of the small number of people who "know what they
are doing" in all respects.  The fact is, almost nobody who is using
computers to get real work done has time for an in-depth study of all
the fine points of numerical mathematics.  The notion that such people
shouldn't try to do numerical computing at all is hopelessly unrealistic,
not to mention obnoxiously elitist.

Without lengthy analysis by experts, it is not possible to say *for sure*
that the answers are right.  However, well-designed tools like IEEE FP
improve the odds a lot.  In particular, they make it much more likely that
problems will be obvious and predictable rather than subtle and mysterious.
This is very important in the real world, where experts are expensive and
in short supply, and a great deal of numerical computing simply has to be
done without them.
-- 
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  henry@zoo.toronto.edu  utzoo!henry