Re: Pseudorandom Permutation Algorithm for Arbitrary Size?

Date	2012-02-16 08:39 -0800
From	Patricia Shanahan <pats@acm.org>
Newsgroups	comp.theory, sci.math, comp.programming
Subject	Re: Pseudorandom Permutation Algorithm for Arbitrary Size?
References	<dfb9f176-c69c-4960-9cdd-f53f805b230c@z31g2000vbt.googlegroups.com> <jhj69p$u9g$1@news.albasani.net>
Message-ID	<OYGdnXTpW9LbrKDSnZ2dnUVZ_qCdnZ2d@earthlink.com> (permalink)

Cross-posted to 3 groups.

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root wrote:
...
> Generate an array of N random numbers. Generate a second array
> of numbers from 0 to N-1, in order. Sort the first array
> in ascending order while simultaneously re-arranging the
> second array to maintain its relation to the first array.
> Use the resulting second array to index your data.

This uses even more memory than the Fisher–Yates shuffle.

Patricia

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Pseudorandom Permutation Algorithm for Arbitrary Size? Andrew Tomazos <andrew@tomazos.com> - 2012-02-16 04:47 -0800
  Re: Pseudorandom Permutation Algorithm for Arbitrary Size? Patricia Shanahan <pats@acm.org> - 2012-02-16 06:22 -0800
  Re: Pseudorandom Permutation Algorithm for Arbitrary Size? James Dow Allen <jdallen2000@yahoo.com> - 2012-02-16 06:57 -0800
  Re: Pseudorandom Permutation Algorithm for Arbitrary Size? root <NoEMail@home.org> - 2012-02-16 15:10 +0000
    Re: Pseudorandom Permutation Algorithm for Arbitrary Size? Patricia Shanahan <pats@acm.org> - 2012-02-16 08:39 -0800
  Re: Pseudorandom Permutation Algorithm for Arbitrary Size? rossum <rossum48@coldmail.com> - 2012-02-16 15:24 +0000

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