Re: st: Update to program - tuples - on SSC

[Nick Cox <njcoxstata@gmail.com>]

Joe was too modest to point out that given his big Mata-based
rewriting of -tuples- he is now the first author.

It follows that all bug reports should be sent to him.

Nick
njcoxstata@gmail.com


On 1 August 2013 20:21, Joseph Luchman <jluchman@gmail.com> wrote:
> With many thanks to Kit Baum, an update to the program - tuples - is
> available on SSC.
>
> The update has two separate version requirements:
>
> For the new standard computation, Stata version 10 is required
>
> For computation with the "nomata" option, Stata version 8 is required.
>
> Nick Cox and I have been working to speed up the algorithm to compute
> all possible tuples which, as is noted in the help file of the
> previous version, is naive and slow for longer lists (i.e., up to or
> greater than 7).
>
> The updated version brings the computation of all "ntuples" into Mata
> using cvpermute().
>
> Computation time savings is especially pronounced around 7
> elements/variables in the list.  For example compare computation speed
> using both:
>
> tuples a b c d e f g h i j, display nomata
>
> tuples a b c d e f g h i j, display
>
>
> The "display" option helps to illustrate the speed boost gained with
> the Mata approach.  Moreover, the speed boost helps to make long lists
> feasible within a _reasonable_ time period.  For example, all
> combinations of letters from a to t (20 elements and 1,048,575
> combinations) in the English alphabet - on my Dell Optiplex 990 with
> an Intel i7-2600 processor (3.4 GHz) with Stata 12.1 MP took about 1.5
> minutes to complete - after this number of elements wait times begin
> to grow more lengthy.
>
> The results are presented in the same way as the previous versions
> (i.e., in the same order), which can be observed by using the
> "display" option.
>
> For users with Stata versions 8 and 9, - tuples - will still work just
> as it did previously, save that you will have to add the "nomata"
> option.
>
> The algorithm has only been tested up to about 23 elements.  Please
> feel free to contact Nick and I about the program if issues are
> encountered during use or for suggestions.
>
>
> To update type:
>
> adoupdate tuples, update
>
>
>
> For an excellent discussion of the command please see Nick's previous
> post on Statalist in 2006.
>
> http://www.stata.com/statalist/archive/2006-12/msg00060.html
>
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/