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Re: Random[..]

• To: mathgroup at smc.vnet.net
• Subject: [mg7348] Re: Random[..]
• From: Lars Hohmuth <larsh>
• Date: Tue, 27 May 1997 22:27:37 -0400 (EDT)
• Organization: Wolfram Research Inc.
• Sender: owner-wri-mathgroup at wolfram.com

mcleod wrote:
> 
> What algorithm does Random[..] use?
> Maybe if it is kept secret the numbers will be more
> random!
> Ian McLeod (aim at uwo.ca)

Actually, the 'Implementation Notes' (Appendix 9.4 in the 3rd release of
the Mathematica book or look in the Help Browser) give the algorithms:

Random uses the Wolfram rule 30 cellular automaton generator for
integers.
(see: Advances in Applied Mathematics, volume 7, pp 123-169 (June 1986))
It uses a Marsaglia­Zaman subtract­with­borrow generator for real
numbers. 
I don't have a reference for that one handy, but it should be quite easy
to find.

You can try out Wolfram rule 30 cellular automaton yourself in the
cellular automata demo notebook in the Demo section of the Help Browser.


Lars Hohmuth
Wolfram Research