I get the second set each time, on Windows, using the build from CRAN. Which BLAS are you using?
On Tue, 14 Sep 2004, Francisco Chamu wrote: > I start a clean session of R 1.9.1 on Windows and I run the following code: > > > library(MASS) > > data(painters) > > pca.painters <- princomp(painters[ ,1:4]) > > loadings(pca.painters) > > Loadings: > Comp.1 Comp.2 Comp.3 Comp.4 > Composition 0.484 -0.376 0.784 -0.101 > Drawing 0.424 0.187 -0.280 -0.841 > Colour -0.381 -0.845 -0.211 -0.310 > Expression 0.664 -0.330 -0.513 0.432 > > Comp.1 Comp.2 Comp.3 Comp.4 > SS loadings 1.00 1.00 1.00 1.00 > Proportion Var 0.25 0.25 0.25 0.25 > Cumulative Var 0.25 0.50 0.75 1.00 > > > > However, if I rerun the same analysis, the loadings of the first > component have the opposite sign (see below), why is that? I have > read the note > in the princomp help that says > > "The signs of the columns of the loadings and scores are arbitrary, > and so may differ between different programs for PCA, and even > between different builds of R." > > However, I still would expect the same signs for two runs in the same session. > > > pca.painters <- princomp(painters[ ,1:4]) > > loadings(pca.painters) > > Loadings: > Comp.1 Comp.2 Comp.3 Comp.4 > Composition -0.484 -0.376 0.784 -0.101 > Drawing -0.424 0.187 -0.280 -0.841 > Colour 0.381 -0.845 -0.211 -0.310 > Expression -0.664 -0.330 -0.513 0.432 > > Comp.1 Comp.2 Comp.3 Comp.4 > SS loadings 1.00 1.00 1.00 1.00 > Proportion Var 0.25 0.25 0.25 0.25 > Cumulative Var 0.25 0.50 0.75 1.00 > > > > R.version > _ > platform i386-pc-mingw32 > arch i386 > os mingw32 > system i386, mingw32 > status > major 1 > minor 9.1 > year 2004 > month 06 > day 21 > language R > > > > BTW, I have tried the same in R 1.9.1 on Debian and I can't reproduce > what I see > on Windows. In fact all the runs give the same as the second run on Windows. > > -Francisco > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > > -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
