Re: random sources (was: Action Groups in Agronomy Study of nursing cows)

[Sven N. Thommesen]

At 05:54 AM 6/26/01, you wrote:
> ok, thanks everybody.
> I just need to know what is the random generator use to determine the 
> order of several events at the same time.
> Is the system (Linux or Windows) random generator or a generator developed 
> by the SDG ?
>
> Olivier JAUZE
> INRA unité URH équipe SP
> Centre de Theix

Olivier,

the Swarm package provides a random library which contains a large number 
of different (pseudo-)random generators plus a smaller number of 
statistical distribution objects. These are all documented reasonably well 
in the Swarm docs.

Every Swarm simulation has a default random generator created upon startup, 
which is referred to as "System.env.randomGenerator" (in Java). It is an 
instance of the MT19937 generator, a Mersenne Twister created by Matsumoto 
and Nishimura. It has a huge period (2^19937) and has been shown to have 
very high statistical quality.

You may of course choose to use the random sources provided by Java or by 
Linux itself, but those are not of as high a quality as MT19937.

Cheers,
Sven Thommesen


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