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From: gisle@spurv.ii.uib.no (Gisle S�lensminde)
Subject: Re: Gnat Chat, Random Numbers in GNAT
Date: 2000/01/24
Date: 2000-01-24T00:00:00+00:00	[thread overview]
Message-ID: <slrn88ocd1.epc.gisle@spurv.ii.uib.no> (raw)
In-Reply-To: SLSi4.702$dw3.34085@news.wenet.net

In article <SLSi4.702$dw3.34085@news.wenet.net>, Kent Paul Dolan wrote:
>Aside:
>On to my main agenda.
>
>I want to do some genetic algorithm (GA) programming in GNAT, to do
>proof of concept for some new approaches I've been mulling to speed up
>convergence and remove the need for sorts, and I need to know about the
>kind and quality of the Ada.Numerics.Float_Random implementation in
>GNAT, to decide whether I can trust it to work well in a statistical
>distribution sense when called (probably) hundreds of millions of times
>in a single program run (you may guess that I have abundant cpu cycles
>at work, and you'd be correct, at least 15 machines behind our firewall
>sit mostly idle for good reason that my using them for week long low
>priority GA runs wouldn't impact significantly).
>
>Header excerpts from the source, from someone who knows right where to
>look, so I don't have to slog through it from a zero knowledge starting
>point, would be a perfectly fine answer, if the info is there.  Formal
>pseudorandom number generator test reports of whatever style have
>become popular since I was last doing that kind of quality control
>personally back in the sixties would be good.  Anecdotal personal
>experience is also welcome as an answer.  URLs pointing to any of the
>non-source code information would be equally useful.
>
>Thanks for any help.  I read and archive this newsgroup daily, so an
>email response is welcome, but not necessary.

In the gnat runtime library sources I found the following comment
in bot the float_random and discrete_random packages, on how they
are implemented. 

--  Note: the implementation used in this package was contributed by
--  Robert Eachus. It is based on the work of L. Blum, M. Blum, and
--  M. Shub, SIAM Journal of Computing, Vol 15. No 2, May 1986. The
--  particular choices for P and Q chosen here guarantee a period of
--  562,085,314,430,582 (about 2**49), and the generated sequence has
--  excellent randomness properties. For further details, see the
--  paper "Fast Generation of Trustworthy Random Numbers", by Robert
--  Eachus, which describes both the algorithm and the efficient
--  implementation approach used here. This paper is available at
--  the Ada Core Technologies web site (http://www.gnat.com).




--
Gisle S�lensminde ( gisle@ii.uib.no )   

ln -s /dev/null ~/.netscape/cookies




  parent reply	other threads:[~2000-01-24  0:00 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-01-24  0:00 Gnat Chat, Random Numbers in GNAT Kent Paul Dolan
2000-01-24  0:00 ` Ted Dennison
2000-01-24  0:00 ` Gisle S�lensminde [this message]
2000-01-24  0:00   ` Jeff Carter
2000-01-26  0:00     ` Kent Paul Dolan
2000-01-26  0:00       ` Jean-Pierre Rosen
2000-01-24  0:00 ` Keith Thompson
2000-01-24  0:00 ` Ehud Lamm
2000-01-25  0:00 ` Nick Roberts
2000-02-05  0:00 ` Robert Dewar
2000-02-06  0:00 ` Ashley Deas Eachus
2000-02-05  0:00   ` Keith Thompson
2000-02-06  0:00     ` Robert Iredell Eachus
2000-02-07  0:00       ` Kent Paul Dolan
2000-02-09  0:00         ` Robert Iredell Eachus
2000-02-06  0:00   ` Kent Paul Dolan
2000-02-06  0:00     ` Robert Iredell Eachus
  -- strict thread matches above, loose matches on Subject: below --
2000-01-26  0:00 Christoph Grein
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