##---- Should be DIRECTLY executable !! ----
##-- ==> Define data, use random,
##-- or do help(data=index) for the standard data sets.
circ.data <- circ.sim(nvar=8,nsub=200)
round(cor(circ.data),2)
## The function is currently defined as
function (nvar = 72 ,nsub = 500,
circum = TRUE, xloading =.6, yloading = .6, gloading=0, xbias=0, ybias = 0,categorical=FALSE, low=-3,high=3,truncate=FALSE,cutpoint=0)
{
avloading <- (xloading+yloading)/2
errorweight <- sqrt(1-(avloading^2 + gloading^2)) #squared errors and true score weights add to 1
g <- rnorm(nsub)
truex <- rnorm(nsub)* xloading +xbias #generate normal true scores for x + xbias
truey <- rnorm(nsub) * yloading + ybias #generate normal true scores for y + ybias
if (circum) #make a vector of radians (the whole way around the circle) if circumplex
{radia <- seq(0,2*pi,len=nvar+1)
rad <- radia[which(radia<2*pi)] #get rid of the last one
} else rad <- rep(seq(0,3*pi/2,len=4),nvar/4) #simple structure
error<- matrix(rnorm(nsub*(nvar)),nsub) #create normal error scores
#true score matrix for each item reflects structure in radians
trueitem <- outer(truex, cos(rad)) + outer(truey,sin(rad))
item<- gloading * g + trueitem + errorweight*error #observed item = true score + error score
if (categorical) {
item = round(item) #round all items to nearest integer value
item[(item<= low)] <- low
item[(item>high) ] <- high
}
if (truncate) {item[item < cutpoint] <- 0 }
return (item)
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