From: geert@fozzie.sun3.iaf.nl (Geert Bosch)
Subject: Re: Random Number Generation
Date: 1996/10/12
Date: 1996-10-12T00:00:00+00:00 [thread overview]
Message-ID: <53o3ot$han@fozzie.sun3.iaf.nl> (raw)
In-Reply-To: 53jgrh$r20@newton.cc.rl.ac.uk
I wrote:
`` This is not a simple example. It is not possible to write an
Ada program that does convert R1 to R2 and is guaranteed to
finish in finite time. ''
Dr J Parker (jp3@rl.ac.uk) responded:
`` Nah... the rejection method is rigorously correct, and so is
the subsequent use of x rem 3 in the code fragment below. ''
I don't say it is not possible to present a correct algorithm
to convert R1 to R2. Such a correct algorithm just is not guaranteed to
finish in finite time.
Your algorithm:
`` x := random;
while x > R1'Last - 1024 rem 3 loop
x := random;
end loop;
return x rem 3; ''
You can't give an upper boundary for the number of iterations
of the while loop if R1 is a truly random generator.
Of course in practise you're only interested in having an
algorithm that has a good probability to finish in a certain
amount of time.
I just pointed out that the example wasn't that simple.
Somebody using this code should be aware of that.
Regards,
Geert
--
E-Mail: geert@sun3.iaf.nl
``I think there is a world market for maybe five computers.''
Thomas Watson, chairman of IBM, 1943
next prev parent reply other threads:[~1996-10-12 0:00 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-10-10 0:00 Random Number Generation Dr J Parker
1996-10-12 0:00 ` Keith Thompson
1996-10-12 0:00 ` Geert Bosch [this message]
-- strict thread matches above, loose matches on Subject: below --
2010-12-30 10:43 Random number generation Mart van de Wege
2010-12-30 10:54 ` Thomas Løcke
2010-12-30 12:11 ` Mart van de Wege
2010-12-30 11:34 ` Niklas Holsti
2010-12-30 11:53 ` Georg Bauhaus
2010-12-30 12:25 ` Mart van de Wege
2010-12-30 15:29 ` Georg Bauhaus
2010-12-30 15:37 ` Mart van de Wege
2010-12-30 11:51 ` Brian Drummond
2010-12-30 12:16 ` Mart van de Wege
2010-12-30 13:04 ` Dmitry A. Kazakov
2010-12-30 13:22 ` Niklas Holsti
2010-12-30 13:39 ` Dmitry A. Kazakov
2010-12-30 13:30 ` Mart van de Wege
2010-12-31 3:14 ` Gene
2010-07-13 12:45 tonyg
2010-07-13 12:50 ` Jacob Sparre Andersen
2010-07-13 12:58 ` Dmitry A. Kazakov
2010-07-13 13:17 ` Thomas Løcke
2010-07-13 16:07 ` Jeffrey R. Carter
2010-07-13 20:33 ` John B. Matthews
2010-07-13 23:02 ` Jeffrey R. Carter
2010-07-14 4:42 ` John B. Matthews
2010-07-15 19:01 ` tonyg
2003-09-26 7:14 random " christoph.grein
2003-09-26 7:00 Andrew
2003-09-26 7:35 ` tmoran
2003-09-26 17:58 ` Andrew
2003-09-26 19:25 ` Andrew
2003-09-26 19:35 ` chris
2003-09-26 21:44 ` tmoran
2003-09-27 1:40 ` Robert I. Eachus
2003-09-27 4:48 ` Andrew
1997-12-19 0:00 Mok-kong Shen
1998-01-02 0:00 ` Mok-kong Shen
1998-01-02 0:00 ` Robert Dewar
1996-10-13 0:00 Random Number Generation parker
1996-10-13 0:00 ` Robert Dewar
1996-10-14 0:00 ` Robert A Duff
1996-10-10 0:00 Dr J Parker
1996-10-02 0:00 Dr J Parker
1996-10-03 0:00 ` Mats Weber
1996-10-07 0:00 ` Geert Bosch
1996-09-23 0:00 Nigel J. Tracey
1996-09-23 0:00 ` Tucker Taft
1996-10-02 0:00 ` Robert I. Eachus
1996-10-02 0:00 ` Nigel J. Tracey
1996-10-03 0:00 ` Nigel J. Tracey
1996-09-25 0:00 ` James_Rogers
1996-09-26 0:00 ` Dale Stanbrough
1996-10-01 0:00 ` Robert I. Eachus
1996-09-30 0:00 ` Dr J Parker
1996-10-01 0:00 ` Tucker Taft
1996-10-01 0:00 ` Keith Thompson
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