Re: [Swarm-Support] Query regarding changing seed in a RNG

[Paul Johnson]

Diego Corredor wrote:
> Hi Steve,
>
> I would like to know if there is a way to change the seed used by the
> ListShuffler. I would like to be sure that the results observed in the
> model that I have programmed are robust to the order of interaction
> among consumers and firms.

Yes.  Look in the swarm source code in ListShuffler.m.  There is a 
creation method "setUniformRandom: " where you can tell the class to use 
a uniform distribution object if you want to create one.  If you do not 
do so, it uses the built in uniform distribution, uniformUnsRand.  That 
distribution object is created automatically for each swarm run, and it 
uses random numbers drawn from the built in randomGenerator object.

I know that's so because in the source code under src/random/random.m I 
find this line:

 uniformUnsRand  = [ UniformUnsignedDist create: globalZone
                        setGenerator: randomGenerator ];


That means if you want to control the seed used with List Shuffler, then 
you either must create your own generator and distribution pair and give 
that to the ListShuffler, or you must reset the seed on randomGenerator 
before you tell the ListShuffler to do anything.


[randomGenerator setStateFromSeed: xxx];


See what I mean?

HTH

pj

>

> Thanks,
>
> Diego Corredor


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Paul E. Johnson                       email: address@hidden
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