Displaying 1 result from an estimated 1 matches for "abfromthetax".
2010 Nov 03
3
optim works on command-line but not inside a function
Dear all,
I am trying to optimize a logistic function using optim, inside the
following functions:
#Estimating a and b from thetas and outcomes by ML
IRT.estimate.abFromThetaX <- function(t, X, inits, lw=c(-Inf,-Inf),
up=rep(Inf,2)){
optRes <- optim(inits, method="L-BFGS-B", fn=IRT.llZetaLambdaCorrNan,
gr=IRT.gradZL,
lower=lw, upper=up, t=t, X=X)
c(optRes$par[2], -(optRes$par[1]/optRes$par[2]) )
}
#Estimating a and b from thetas an...