## File Name: rm_facets_est_tau_item.R
## File Version: 0.20
#####################################################
# estimation of tau.item parameters
rm_facets_est_tau_item <- function( b.item, b.rater, Qmatrix, tau.item,
VV, K, I, TP, a.item, a.rater, item.index, rater.index,
n.ik, numdiff.parm=.001, max.b.increment=1,theta.k, msteps,
mstepconv, tau.item.fixed, tau.item.fixed_val )
{
h <- numdiff.parm
diffindex <- item.index
RR <- length(b.rater)
Q0 <- matrix(0,nrow=VV, ncol=K)
se.tau.item <- Q0
cat(" M steps tau.item parameter |")
it <- 0
conv1 <- 1000
#--- input rm_facets_calcprobs
args <- list( b.item=b.item, b.rater=b.rater, Qmatrix=Qmatrix, tau.item=tau.item, VV=VV, K=K,
I=I, TP=TP, a.item=a.item, a.rater=a.rater, item.index=item.index,
rater.index=rater.index, theta.k=theta.k, RR=RR )
#--- begin M-steps
while( ( it < msteps ) & ( conv1 > mstepconv ) ){
tau.item11 <- tau.item0 <- tau.item
for (kk in 1:K){
Q1 <- Q0
Q1[,kk] <- 1
#-- compute expected likelihood
args$tau.item <- tau.item11
pjk <- do.call( what=rm_facets_calcprobs, args=args)
args$tau.item <- tau.item11 + h*Q1
pjk1 <- do.call( what=rm_facets_calcprobs, args=args)
args$tau.item <- tau.item11 - h*Q1
pjk2 <- do.call( what=rm_facets_calcprobs, args=args)
#-- compute increments
res <- rm_numdiff_index( pjk=pjk, pjk1=pjk1, pjk2=pjk2, n.ik=n.ik, diffindex=diffindex,
max.increment=max.b.increment, numdiff.parm=numdiff.parm )
increment <- Q1*matrix( res$increment, nrow=VV, ncol=K)
tau.item <- tau.item + increment
se.tau.item[,kk] <- sqrt(abs(-1/res$d2) )
}
if ( ! is.null( tau.item.fixed_val ) ){
MK <- ncol( tau.item.fixed_val )
for ( kk in 1:MK){
ind <- which( ! is.na( tau.item.fixed_val[,kk]) )
if ( length(ind) > 0 ){
tau.item[ ind, kk] <- tau.item.fixed_val[ ind, kk]
}
}
}
conv1 <- max( abs( tau.item - tau.item0 ) )
it <- it+1
cat("-")
if ( ! is.null(tau.item.fixed) ){
tau.item[ tau.item.fixed[,1:2,drop=FALSE] ] <- tau.item.fixed[,3]
}
}
cat(" ", it, "Step(s) \n")
#-- output
res <- list(tau.item=tau.item, se.tau.item=se.tau.item, ll=sum(res$ll0) )
return(res)
}
.rm.facets.est.tau.item <- rm_facets_est_tau_item
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