Not so easy to do exactly---but you get a decent approximation by simply running a p-bit block cipher in counter mode. On Thu, May 29, 2014 at 3:47 PM, Warren D Smith <warren.wds@gmail.com> wrote:
The "Gray code" is a fast way to produce the integers 0,1,2,..2^p-1 in an order such that each differs from predecessor in exactly 1 bit.
Q1 (easy). Find an anti-Gray code where each differs from predecessor in exactly p-1 bits.
Q2 (not so easy). Find a "mid-gray" code where each differs from predecessor in exactly p/2 bits (p>1 even). Note this is impossible if p is a multiple of 4.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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