[R] PCA and MDS

[Prof Brian Ripley]

On Wed, 22 Jun 2005, Guohui Ding wrote:

> prcomp(stats) Principal Components Analysis
> princomp(stats) Principal Components Analysis
> scale(base) Scaling and Centering of Matrix-like Objects

The first two are correct for PCA, but scale is not MDS.

MDS is available in cmdscale (stats), isoMDS (MASS), sammon (MASS) and 
elsewhere.

>> I am not familar with R. I want to use PCA (principal components
>> analysis) and MDS (multidimensional scaling). Can someone tell me
>> which R package I should use for PCA and MDS? I appreciate your help
>> in advance.

-- 
Brian D. Ripley,                  ripley at 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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595