From ripley@stats.ox.ac.uk  Wed Apr  7 15:46:44 1999
From: ripley@stats.ox.ac.uk (Prof Brian D Ripley)
Date: Wed, 7 Apr 1999 15:46:44 +0100 (BST)
Subject: chull() wanted?
In-Reply-To: <XFMail.990407162556.steuer@amadeus.statistik.uni-dortmund.de>
Message-ID: <Pine.GSO.4.05.9904071543310.10385-100000@auk.stats>

On Wed, 7 Apr 1999, Dipl.-Stat. Detlef Steuer wrote:

> Hello!
> 
> Is there someone already working on an implementation of Splus'
> chull() function for R?
> If not, I would like volunteer to try it.
> 
> For my "Diplom" I implemented convex peeling in C (some time ago),
>  using an O(n log(n)) algorithm, so it probably will prove relatively easy to
> use that code for a R-function.

If only you had volunteered a month ago!

There is one implementation in package sm, and a cleaner one in 0.64, due
out today.  Both as versions of Eddy's 1977 algorithm. I would be happy to
replace the present chull by something better, though. It doesn't do
peeling, but that is easy to arrange in R: just remove the convex hull and
repeat.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._


chull() wanted?
Prof Brian D Ripley