Re: [OctDev] random numbers for distributed computations

[Michael C. <mic...@ua...>]

On Monday 11 April 2005 11:57, Francesco Potorti` wrote:
> >I have a question about this. If a RNG has a period of X, that means that
> >there are X unique values that are generated, and then the sequence
> > repeats.
>
> No, it means that the sequence repeats after X values are produced.  The
> period length says nothing about the space of values.  However, for good
> general purpose generators, the size of the space of values is much
> smaller than the period.

OK, you're saying that a generator with period 5 could produce values like
1 2 2 1 2 *** 1 2 2 1 2 *** 1 2 2 1 2
so the set of unique values is smaller than the period, correct?

This may be, but for the moment my main question is whether the set of unique 
values that is generated depends upon the initial seed, or whether it's just 
the starting point in the sequence that depends on the initial seed. Could 
the unique values be 3 and 4, say, or will they always be 1 and 2?
M.