Message-ID: <33241CA7.4E84@pobox.oleane.com>
Date: Mon, 10 Mar 1997 15:37:27 +0100
From: Francois Charton <deef AT pobox DOT oleane DOT com>
Organization: CCMSA
MIME-Version: 1.0
To: Paul Derbyshire <ao950 AT FreeNet DOT Carleton DOT CA>
CC: djgpp AT delorie DOT com
Subject: Re: a randomize function for DJGPP?
References: <5flbpp$m74 AT nr1 DOT ottawa DOT istar DOT net> <331FC0D1 DOT 1A26 AT cs DOT com> <E6oqJs DOT K2n AT boss DOT cs DOT ohiou DOT edu> <5fps67$pc3 AT news DOT ox DOT ac DOT uk> <5g0b8s$snb AT freenet-news DOT carleton DOT ca>
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Paul Derbyshire wrote:
> 
> Ironically, the old Commodore 64 had possibly the best random generator:
> an ANALOG white noise chip in the sound card, which could be tapped by a
> program to obtain random numbers. Obviously for uniform randomness of the
> quality you describe, an analog white noise generator filtered to digital
> is what's needed. 
>

In many scientific applications using random numbers (I think the poster 
was talking about Monte Carlo integration), there is a double problem : 
you need randomness, but you also need your calculations to be 
repeatable. This makes non repeatable generators, like white noise chips, 
less useful in such cases.

Also, it is very hard to tell whether a white noise generating chip is 
"truly" random (for instance, time elapsed between counts from a Geiger 
counter can be proved to be slightly correlated...). 

Francois