[Python-ideas] About adding a new iteratormethodcalled "shuffled"

Jacob Holm jh at improva.dk
Fri Mar 27 12:45:53 CET 2009

Greg Ewing wrote:
> Jacob Holm wrote:
>> However, by repeated shuffling and reseeding like the OP suggested, 
>> you can in theory get to all elements of G_n
> But then you need a sufficient number of distinct seed
> values, so you're back to the original problem.
Ehr, no. Suppose my PRNG only has period two and the shuffle based on it 
can only generate the permutations [1, 0, 2] and [2, 1, 0] from [0, 1, 
2]. Each time I reseed from a truly random source, the next shuffle will 
use one of those permutations at random. By shuffling and reseeding 
enough times I can get all combinations of those two permutations. This 
happens to be all 6 possible permutations of 3 elements.

- Jacob

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