Re: Random number generation

[tonyg <tonythegair@googlemail.com>]

On 14 July, 05:42, "John B. Matthews" <nos...@nospam.invalid> wrote:
> In article <i1irmb$vf...@tornado.tornevall.net>,
>  "Jeffrey R. Carter" <spam.jrcarter....@spam.acm.org> wrote:
>
> > On 07/13/2010 01:33 PM, John B. Matthews wrote:
>
> > > The shuffling algorithm needs work; this might be an alternative:
>
> > > <http://en.wikipedia.org/wiki/Fisher–Yates_shuffle>
>
> > The problem with this (for Ada) is the need to instantiate
> > Discrete_Random for a different range each time (although you could
> > use PragmARC.Universal_Random.Random_Int).
>
> Thank you for suggesting this; I see the problem, now. Section
> A.5.2(50), Note 16, mentions the very problem, suggesting Float_Random
> as an alternative:
>
> <http://www.adaic.com/standards/05rm/html/RM-A-5-2.html>
>
> I also found this implementation using Discrete_Random:
>
> <http://rosettacode.org/wiki/Knuth_shuffle#Ada>
>
> > If it's for a game with a human, then the biased version of using the
> > full range each time is good enough.
>
> No, it's a simulation; I don't get off that easy.
>
> > > As an aside, Mine Detector V6.0 builds on Mac OS X 10.5.8 with GtkAda
> > > 2.14.1 and GNAT 4.3.4. Wait, I took a picture:
>
> > > <http://i26.tinypic.com/23qyxxi.png>
>
> > Cool. I wouldn't check any boxes with only 100 mines.
>
> They were smiling for the camera! :-)
>
> --
> John B. Matthews
> trashgod at gmail dot com
> <http://sites.google.com/site/drjohnbmatthews>

Thanks for the help guys