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From: mdr@reed.UUCP (Mike Rutenberg)
Newsgroups: sci.math,sci.physics,sci.crypt,sci.math.stat
Subject: Re: Do you use RANDOM NUMBERS?
Message-ID: <5722@reed.UUCP>
Date: Thu, 19-Mar-87 13:32:09 EST
Article-I.D.: reed.5722
Posted: Thu Mar 19 13:32:09 1987
Date-Received: Sat, 21-Mar-87 08:10:06 EST
References: <5712@reed.UUCP> <553@entropy.ms.washington.edu>
Reply-To: mdr@reed.UUCP (Mike Rutenberg)
Organization: Reed College, Portland, OR
Lines: 25
Keywords: Random numbers, leprechauns
Xref: mnetor sci.math:758 sci.physics:940 sci.crypt:255 sci.math.stat:71


  "For most applications real random numbers are undesirable.  Consider
   debugging a monte-carlo or simulation program when you cannot repeat
   the sequence that led to the problem."  [Don Martin]

I agree that tracking a specific bug in a Monte-Carlo simulation is
easier with a repeatable sequence, but what about running the thing for
real.  Especially for long running simulations, I'm not sure how much I
trust psudeo-random generator libraries, especially if I have a pretty
good sense of just how random my hardware is.

I find it a little curious that people are trying to simulate particles
and other widgets using predictable perturbations (i.e. psudeo-random
numbers) - it feels like playing with fire unless you really understand
exactly how the simulation might be effected by the flavor of random numbers
you're using -- AND THAT'S EXACTLY WHY YOU ARE DOING THE SIMULATION.

Am I confused?

Mike

ps. From all I can tell, hardware random numbers are quite a bit slower
    to generate than psuedo-random numbers, but then there are hybrid schemes.
-- 
	Reed College -- Portland, Oregon -- 503/774-9192