On Sun, Oct 18, 2009 at 10:42 PM, Peng Yu <pengyu...@gmail.com> wrote: > Some webpage has described prcomp and princomp, but I am still not > quite sure what the major difference between them is. Can they be used > interchangeably? > > In help, it says > > 'princomp' only handles so-called R-mode PCA, that is feature > extraction of variables. If a data matrix is supplied (possibly > via a formula) it is required that there are at least as many > units as variables. For Q-mode PCA use 'prcomp'. > > > What are R-mode and Q-mode? Are they just too different numerical > methods to compute PCA?
Also, it seems that 'loadings' of princomp is the same as 'rotation' of prcomp. I'm wondering whey they have different names in the two functions. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
