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Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!mips!apple!apple.com!desnoyer
From: desnoyer@apple.com (Peter Desnoyers)
Newsgroups: comp.theory,comp.misc,comp.lang.misc
Subject: Re: Modulus (Re: hashing function for strings)
Message-ID: <6790@internal.Apple.COM>
Date: 20 Feb 90 01:15:09 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 16
References:<1990Feb15.211210.22950@max.sunysb.edu> <0ZqzBRm00WA1M0d5JZ@andrew.cmu.edu> <7416@ogicse.ogc.edu> <10940@saturn.ADS.COM> <E1wt*4@cs.psu.edu> <10946@saturn.ADS.COM>

In article <10946@saturn.ADS.COM> xanthian@saturn.ADS.COM (Metafont 
Consultant Account) writes:
> I see the idea of a modulus function that doesn't change if the axis
> is shifted left or right by the mod base, rather than one that suffers
> an ugly reflection at the origin, as inherently beautiful, in the math
> sense.  It is also inherently more useful, in the graphics programming
> sense.

It is more than just pretty. The integers mod M has M elements, usually 
represented as 0..M-1.  A modulo operator that results in {integers mod M} 
having 2M-1 elements is either incorrectly named or incorrectly implemented.


                                             Peter Desnoyers
                                             Apple ATG
                                             desnoyer@apple.com