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
next prev 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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