[R] test h-f sphericity test?

[John Christie]

	I posted some R code that could be an h-f sphericity test.  Is there 
anyone out there with SPSS, Systat, or some other package that has a 
built in test who can verify whether it is accurate or not?

John

(here is the code again)
# This returns the Huynh-Feldt or "Box Correction" for degrees of 
freedom
hf <- function(m){
	# m is a matrix with subjects as rows and conditions as columns
	# note that checking for worst case scenarios F correction first might
	# be a good idea using J/(J-1) as the df correction factor
	n<- length(m[,1])
	J<-length(m[1,])
	X<-cov(m)*(n-1)
	r<- length(X[,1])
	D<-0
	for (i in 1: r) D<- D+ X[i,i]
	D<-D/r
	SPm<- mean(X)
	SPm2<- sum(X^2)
	SSrm<-0
	for (i in 1: r) SSrm<- SSrm + mean(X[i,])^2
	epsilon<- (J^2*(D-SPm)^2) / ((J-1) * (SPm2 - 2*J*SSrm + J^2*SPm^2))
	epsilon
}