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Re^2: Random Math Questionby sk (Curate) 
on Oct 11, 2005 at 05:43 UTC ( #499036=note: print w/ replies, xml )  Need Help?? 
blokhead, Thanks for all the wonderful explanations. Let's for this discussion assume that all we need is an algorithm that can potentially produce every p! permutation of a sequence (1..p) I was wondering whether a two dimensional shuffling (not sure if that is the right term) would help us achieve such a suffle without having to resort to a random variable with entropy 1516705 bits. Here are the steps i have in mind  1. Partition the sequence into klists (each list containing nelements) and that each list can be truly randomized. Also WLOG let's assume k <= n 2. For all i 1 to n and j = 1 to k, a. generate integers (X,Y) ~ U from the planar region bounded by x = n and y = k. b. Now we swap element(i,j) with element(X,Y). Since each (i,j) is equally likely => i*n+j is equally likely. Is there anything wrong with this approach? Thanks, cheers SK
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