Subject: [R] Factor Rotation
From: Barry Cooke (bcooke@gpu.srv.ualberta.ca)
Date: Thu 27 Apr 2000 - 04:46:42 EST
Message-ID: <Pine.A41.4.10.10004261244230.45618-100000@gpu5.srv.ualberta.ca>
How does one rotate the loadings from a principal component analysis?
Help on function prcomp() from package mva mentions rotation:
Arguments
retx a logical value indicating whether the rotated
variables should be returned.
Values
rotation the matrix of variable loadings (i.e., a matrix
whose olumns contain the eigenvectors). The
function princomp returns this in the element
loadings.
x if retx is true the value of the rotated data
(the data multiplied by the rotation matrix)
is returned.
but it is unclear to me exactly how the rotation is to be done.
For instance how would one specify a varimax rotation? Or are
loadings, by default, rotated by the varimax method in prcomp()?
MASS v2 describes the function rotate() on p. 409-410; however R
complements does not cover this. A search of CRAN indicates Peter
Ho <peter@esb.ucp.pt> asked the same question Sept 29, 1999, but
I found no reply.
Thanks. Using R 1.0.0 on Windows 9x.
Barry J. Cooke Current mailing address:
Ph.D. Candidate #219 - 1810 NW 23 Blvd
Environmental Biology and Ecology Gainesville, Florida, USA
Department of Biological Sciences 32605
University of Alberta
Edmonton, AB, T6G 2E9 http://www.ualberta.ca/~bcooke
bcooke@gpu.srv.ualberta.ca
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