Shuffling Machines

[Louie Landale]

That discussion doesn't seem to take into account a key feature of shuffling: how many cards are in each group that gets interleaved: if I cut the deck at exactly 26 and then "riffle" each half with exactly 13 cards each, its going to take more than 7 shuffles to randomize the deck. Similarly if the cut it exactly in half and then riffle 26 groups of 1 card each, you could predict the outcome, thus losing the desirable "random" feature of a "good suffled deck".

I have no idea what a "perfect" suffling algorithm is, but I'm sure it features some randomness of how many cards are in each half of the deck, and also features some randomness on how many cards are in each riffle-group. And large riffle-groups are a lot less likely than small riffle-groups (6 cards are a LOT less likely than 1 card).

- Louie