Re: Compare two methods of random permutations

From	Mok-Kong Shen <mok-kong.shen@t-online.de>
Newsgroups	comp.programming
Subject	Re: Compare two methods of random permutations
Date	2013-05-13 21:09 +0200
Organization	albasani.net
Message-ID	<kmrdpe$njc$1@news.albasani.net> (permalink)
References	<kmegeh$921$1@news.albasani.net> <a79b56db-b5df-40f3-a764-390e42f65094@googlegroups.com>

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Am 13.05.2013 17:26, schrieb bob:
> Why would you not use the method of random permutation that is
> theoretically perfect?

It was my fault that I din't cross-post to 2 groups (thus I later
requested you to kindly look up there). I explained in sci.stat.math
my motivation as follows (note also that n=52 is only an example case):

...... In particular I don't need to
generate the whole range of possible permutations but on the other hand
a not too limited small range. Consider the case n=52, one knows that
in-shuffle and out-shuffle have periods of 52 and 8 respectively, which
are negligibly small compared to the whole range (of size (52!)). On the
other hand, the method of Fisher and Yates needs n-1 (pseudo-)random
numbers. In one of my applications a couple of such random numbers are
already available for other reasons, so it would certainly be
conveninent and advantageous, if I could just use them for doing random
permutation without having to invoke a PRNG to acquire the n-1 random
numbers needed for F&Y. This was the motivation of my OP and, as it
turns out, my scheme runs also much faster than F&Y as reported further
below.

M. K. Shen

Thread

Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-08 23:35 +0200
  Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-11 21:31 -0700
    Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-13 08:07 +0200
      Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-13 02:34 -0700
  Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-13 08:01 +0200
  Re: Compare two methods of random permutations bob <bob@coolfone.comze.com> - 2013-05-13 08:26 -0700
    Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-13 11:42 -0700
      Re: Compare two methods of random permutations bob <bob@coolfone.comze.com> - 2013-05-16 13:46 -0700
    Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-13 21:09 +0200
      Re: Compare two methods of random permutations bob <bob@coolfone.comze.com> - 2013-05-13 12:57 -0700
        Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-13 22:59 +0200
          Re: Compare two methods of random permutations bob <bob@coolfone.comze.com> - 2013-05-13 15:28 -0700
            Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-14 10:54 +0200
              Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-14 05:32 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-14 22:46 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-14 14:19 -0700
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-14 15:06 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-15 10:16 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-15 03:54 -0700
                Re: Compare two methods of random permutations Patricia Shanahan <pats@acm.org> - 2013-05-15 07:11 -0700
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-15 11:04 -0700
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-15 11:06 -0700
                Re: Compare two methods of random permutations Patricia Shanahan <pats@acm.org> - 2013-05-15 12:55 -0700
                Re: Compare two methods of random permutations "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-05-16 06:10 +0100
                Re: Compare two methods of random permutations pacman@kosh.dhis.org (Alan Curry) - 2013-05-16 06:57 +0000
                Re: Compare two methods of random permutations "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-05-16 09:26 +0100
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-16 01:35 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-17 14:11 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-17 08:13 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 11:06 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-19 03:14 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 13:26 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-19 04:59 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 14:13 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-19 05:52 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 15:06 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-19 06:50 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 16:14 +0200
                Re: Compare two methods of random permutations James Dow Allen <jdallen2000@yahoo.com> - 2013-05-19 08:11 -0700
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 17:15 +0200
                Re: Compare two methods of random permutations Mok-Kong Shen <mok-kong.shen@t-online.de> - 2013-05-19 17:24 +0200

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