R/gdina_calc_prob_one_item.R

In CDM: Cognitive Diagnosis Modeling

## File Name: gdina_calc_prob_one_item.R
## File Version: 0.06

gdina_calc_prob_one_item <- function( J, jj, L, aggr.attr.patt, Mj, delta,
        linkfct)
{
    pj1 <- matrix( 0, nrow=1, ncol=L )
    #---- calculate P(X_j | alpha_l )
    ajj <- ( aggr.attr.patt[[jj]] )
    mjjj <- Mj[[jj]][[1]][ ajj, ]
    djj <- matrix( delta[[jj]], nrow=L, ncol=length(delta[[jj]]), byrow=TRUE )
    pj1[1,] <- rowSums( mjjj * djj )
    if (linkfct=="logit"){
        pj1[1,] <- stats::plogis( pj1[1,] )
    }
    if (linkfct=="log"){
        pj1[1,] <- exp( pj1[1,] )
    }
    #-- restrict probabilities in calculations
    eps <- 1E-10
    pj1[ pj1 < 0 ] <- eps
    pj1[ pj1 > 1 ] <- 1 - eps
    #-- create array
    pjM <- array( NA, dim=c(1,2,L) )
    pjM[,1,] <- 1 - pj1
    pjM[,2,] <- pj1
    pjM <- pjM[1,,]
    #--- OUTPUT
    return(pjM)
}