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Re: st: combinatorics


From   James Muller <james.muller@internode.on.net>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: combinatorics
Date   Wed, 17 Aug 2005 22:24:58 +1000

Mata sounds good (I wonder how it compares to an optimized C-based plugin). The algorithm is loop-based, so compilation really helps for anything big. Would be nice to be able to do permutations 20 choose 5 and get something back before the release of Stata 10.

Any more thoughts?

James


Roger Newson wrote:


At 04:23 17/08/2005, James wrote:

Does anybody know of a package that generates permutations and combinations? That is, the actual ordered/unordered sets of combinations or permutations of elements from a set.

I wrote a little package that does this for the set {1,2,...,n} a few months ago, and just want to check that there isn't already something equivalent out there.

Also, does anybody have a wishlist of combinatoric operations that they would like to see in Stata, other than for the generation of the above sequences?

If I type

findit permut

then I find a lot about permutation tests, but nothing that looks like a package to generate a full set of permutations or combinations.

James should probably send his package to SSC. I don't know if James is using Mata in this project, but it is probably a good idea.

Best wishes

Roger



--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
Division of Asthma, Allergy and Lung Biology
King's College London

5th Floor, Capital House
42 Weston Street
London SE1 3QD
United Kingdom

Tel: 020 7848 6648 International +44 20 7848 6648
Fax: 020 7848 6620 International +44 20 7848 6620
or 020 7848 6605 International +44 20 7848 6605
Email: roger.newson@kcl.ac.uk
Website: http://phs.kcl.ac.uk/rogernewson/

Opinions expressed are those of the author, not the institution.

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