Displaying 1 result from an estimated 1 matches for "pzleneg".
2010 Nov 03
3
optim works on command-line but not inside a function
...- function(theta, z, l){
epow <- exp(-(z+l*theta))
result <- 1/(1+epow)
result
}
#as IRT.oneOverP but now for IRT.pZL
IRT.pZLepos <- function(theta, z, l){
epow <- exp(-(z+l*theta))
result <- (1+epow)
result
}
#as IRT.oneOverPneg but now for IRT.pZL
IRT.pZLeneg <- function(theta, z, l){
epow <- exp(z+l*theta)
result <- (1+epow)
result
}
#The loglikelihood of IRT, but now expressed in terms of z and l
IRT.llZetaLambda <- function(params, t, X){
pos<- sum(t * log(IRT.pZL( X,params[1],params[2]) ))
neg<- sum( (1-t)...