R/gdina_itemfit.R

In CDM: Cognitive Diagnosis Modeling

## File Name: gdina_itemfit.R
## File Version: 0.05

gdina_itemfit <- function( L, J, R.lj, I.lj, item.patt.freq, G, attr.prob, data, pjM )
{
    # # n.ik [ 1:TP, 1:I, 1:(K+1), 1:G ]
    n.ik <- array( 0, dim=c(L, J, 2, 1 ) )
    n.ik[,, 2, 1 ] <- t(R.lj)
    n.ik[,, 1, 1 ] <- t(I.lj-R.lj)
    pi.k <- array( 0, dim=c(L,1) )

    if (G>1){    # item fit only in multiple group case
        g1 <- colSums( item.patt.freq )
        g1 <- g1 / sum(g1)
        for (gg in 1:G){
            pi.k[,1] <- pi.k[,1] + attr.prob[,gg] * g1[gg]
        }
    }

    if (G==1){    # item fit only in one group case
        pi.k[,1] <- attr.prob$class.prob
    }
    probs <- aperm( pjM, c(3,1,2) )
    itemfit.rmsea <- itemfit.rmsea( n.ik=n.ik, pi.k=pi.k, probs=probs )$rmsea
    names(itemfit.rmsea) <- colnames(data)
    #--- OUTPUT
    res <- list( itemfit.rmsea=itemfit.rmsea, pi.k=pi.k, n.ik=n.ik, pi.k=pi.k)
    return(res)
}