[Python-Dev] a note in random.shuffle.__doc__ ...
Greg Ewing
greg.ewing at canterbury.ac.nz
Sun Jun 11 02:39:42 CEST 2006
Terry Jones wrote:
> That doc note should surely be removed. Perhaps it's an artifact from some
> earlier shuffle algorithm.
>
> The current algorithm (which is simple, well known, and which produces all
> permutations with equal probability) only calls the RNG len(x) - 1 times.
It's not a matter of how many times it's called, but
of how much internal state it has.
A generator with only N possible internal states can't
possibly result in more than N different outcomes from
any algorithm that uses its results.
--
Greg
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