Re: st: combinatorics

[James Muller <james.muller@internode.on.net>]

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
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> 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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