From gavin.simpson at ucl.ac.uk  Fri Mar  2 17:53:11 2007
From: gavin.simpson at ucl.ac.uk (gavin.simpson at ucl.ac.uk)
Date: Fri,  2 Mar 2007 17:53:11 +0100 (CET)
Subject: [Rd] Wishlist: Make screeplot() a generic (PR#9541)
Message-ID: <20070302165311.447935AD11@slim.kubism.ku.dk>

Full_Name: Gavin Simpson
Version: 2.5.0
OS: Linux (FC5)
Submission from: (NULL) (128.40.33.76)


Screeplots are a common plot-type used to interpret the results of various
ordination methods and other techniques. A number of packages include ordination
techniques not included in a standard R installation. screeplot() works for
princomp and prcomp objects, but not for these other techniques as it was not
designed to do so. The current situation means, for example, that I have called
a function Screeplot() in one of my packages, but it would be easier for users
if they only had to remember to use screeplot() to generate a screeplot.

I would like to request that screeplot be made generic and methods for prcomp
and princomp added to R devel. This way, package authors can provide screeplot
methods for their functions as appropriate.

I have taken a look at the sources for R devel (from the SVN repository) in file
princomp-add.R and prcomp.R and it looks a relatively simple change to make
screeplot generic.

I would be happy to provide patches and documentation if R Core were interested
in making this change - I haven't done this yet as I don't want to spend time
doing something that might not be acceptable to R core in general.

Many thanks,

G



[Rd] Wishlist: Make screeplot() a generic (PR#9541)
gavin.simpson at ucl.ac.uk