Path: utzoo!attcan!uunet!husc6!mailrus!cornell!uw-beaver!uw-june!rik
From: rik@june.cs.washington.edu (Rik Littlefield)
Newsgroups: comp.arch
Subject: Re: Professional Programmers (was: Seeing the future)
Message-ID: <6793@june.cs.washington.edu>
Date: 25 Dec 88 00:53:33 GMT
References: <1984@eos.UUCP> <28200245@mcdurb> <321@taux02.UUCP> <32353@think.UUCP> <10790@tekecs.TEK.COM>
Organization: U of Washington, Computer Science, Seattle
Lines: 19

In article <10790@tekecs.TEK.COM>, andrew@frip.gwd.tek.com (Andrew Klossner) 
writes:
> >> [ stuff about converting cos(atan(x)) to 1/(1+x*x) and why this has
> >>   not much to do with programmers as opposed to mathematicians     ]
> 
> > This is exactly the point I was trying to make - to a mathematician,
> > these two expressions are identical and interchangeable ...
> 
> To an experienced programmer, these expressions are not
> interchangeable; the first implies a runtime range check on the value
> of x.

I cannot resist asking.  Since the domain of atan includes all real numbers,
and the range of atan is surely within the domain of cos, what exactly will
the runtime range check be doing?  :-)

Merry Christmas, all!

--Rik