Arlindo Meque <mequitomz <at> yahoo.com.br> writes: > > > Dear all, > > I've used the 'prcomp' command to > calculate the eigenvalues and eigenvectors of a matrix(gg). > > Using the command 'principal' from the > 'psych' package I've performed the same exercise. I got the same > eigenvalues but different eigenvectors. Is there any reason for that > difference?
[snip] eigenvectors are only defined up to a scale factor. prcomp is scaling them so that the sum of squares is 1; I haven't bothered to see how principal() is scaling them (maybe the documention says). (1,1) and (-1,1) , or (1,1) and (1,-1), would have been equally valid choices. Ben Bolker ______________________________________________ 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.
