psych (version 1.0-17)

factor.rotate: "Hand" rotate a factor loading matrix

Description

Given a factor or components matrix, it is sometimes useful to do arbitrary rotations of particular pairs of variables. This supplements the much more powerful rotation package GRProtation and is meant for specific requirements to do unusual rotations.

Usage

factor.rotate(f, angle, col1, col2)

Arguments

f

original loading matrix

angle

angle (in degrees!) to rotate

col1

column in factor matrix defining the first variable

col2

column in factor matrix defining the second variable

Value

• the resulting rotated matrix of loadings.

Details

Partly meant as a demonstration of how rotation works, factor.rotate is useful for those cases that require specific rotations that are not available in more advanced packages such as GPAroation.

References

http://personality-project.org/revelle/syllabi/405.syllabus.html

Examples

## The function is currently defined as
function(f,angle,col1,col2)  {
   #hand rotate two factors from a loading matrix
   #see the GPArotation package for much more elegant procedures
     nvar<- dim(f)[2]
     rot<- matrix(rep(0,nvar*nvar),ncol=nvar)
     rot[cbind(1:nvar, 1:nvar)] <- 1
     theta<- 2*pi*angle/360
     rot[col1,col1]<-cos(theta)
     rot[col2,col2]<-cos(theta)
     rot[col1,col2]<- -sin(theta)
     rot[col2,col1]<- sin(theta)
     result <- f %*% rot
     return(result) }