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How many times should you shuffle a deck of cards? [pdf]

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• jazzychad 17y ago
  Related: http://news.ycombinator.com/item?id=966243 http://news.ycombinator.com/item?id=966243 (uses some of the same probabilistic models and rising sequences) I also wrote a simple javascript card-shuffling library based on these models after reading the davidson.edu article: http://jazzychad.com/js/deck.php http://jazzychad.com/js/deck.php
• xenophanes 17y ago
  so, how many times? i read parts of the pdf but didn't find the answer. i did see it say 7 isn't enough.
  • trebor 17y ago
    Basically, "the more the better". In lieu of a summary, let me try to see if I understand it. The deck is more random: the more times you shuffle, the more cuts you make, and the more you randomize the size of your cuts. To draw my own conclusion, the more chaos you throw into your method (which may even include lesser amounts of shuffling) the better the randomness of the deck should be.
    • anamax 17y ago
      > Basically, "the more the better". Actually, no. Too much shuffling actually makes some sequences less likely. See http://www-stat.stanford.edu/~susan/courses/b494/index/node109.html http://www-stat.stanford.edu/~susan/courses/b494/index/node1... For some simpler math for a related question, see http://20bits.com/articles/interview-questions-shuffling-an-array/ http://20bits.com/articles/interview-questions-shuffling-an-...
  • Panoramix 17y ago
    What I got from it is that it depends on what kind of measure you use for the randomness of the deck. Using a certain measure they obtain about 7, and with another one they get 11-12.
• Me3748594 17y ago
  6