[Rd] Wishlist: Make screeplot() a generic (PR#9541)

gavin.simpson at ucl.ac.uk gavin.simpson at ucl.ac.uk
Fri Mar 2 17:53:11 CET 2007

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

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,


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