R/gdina_init_item_parameters.R

In CDM: Cognitive Diagnosis Modeling

## File Name: gdina_init_item_parameters.R
## File Version: 0.10

gdina_init_item_parameters <- function( delta.init, linkfct, J, seed, Mj,
    delta.basispar.init, delta.designmatrix, Mj.index, rule )
{
    delta <- delta.init
    if ( is.null( delta.init ) ){
        #**** identity link
        if (linkfct=="identity" ){
            for (jj in 1:J){
                N1jj <- ncol(Mj[[jj]][[1]])
                l1 <- rep(0,N1jj)
                if ( seed==0 ){
                    dd1 <- .2 ; dd2 <- .6
                } else {
                    dd1 <- stats::runif( 1, 0, .4 )
                    dd2 <- stats::runif( 1, 0, 1 - dd1 - .1 )
                }
                l1[1] <- dd1
                l1[2:N1jj] <- rep( dd2 / (N1jj - 1), N1jj - 1 )
                delta[[jj]] <- l1
            }
        }
        #**** logit link
        if (linkfct=="logit" ){
            for ( jj in 1:J){
                N1jj <- ncol(Mj[[jj]][[1]])
                l1 <- rep(0,N1jj)
                l1[1] <- -2
                l1[-1] <- 4 / N1jj
                delta[[jj]] <- l1
            }
        }
        #**** log link
        if (linkfct=="log" ){
            for ( jj in 1:J){
                N1jj <- ncol(Mj[[jj]][[1]])
                l1 <- rep(0,N1jj)
                if ( seed==0 ){
                    dd1 <- -1.5 ; dd2 <- .75
                } else {
                    dd1 <- stats::runif( 1, -3, -1 )
                    dd2 <- stats::runif( 1, .25, 1 )
                }
                l1[1] <- dd1
                l1[N1jj] <- dd2
                if ( rule[jj]=="ACDM"){
                    v1 <- .5 + 0*l1
                    v1[1] <- .80
                    l1 <- rrumpars2logpars(v1)
                }
                delta[[jj]] <- l1
            }
        }
    }
    ###########################
    # import inits delta basis parameter
    if ( ! is.null( delta.basispar.init ) ){
        u.delta <- delta.designmatrix %*% delta.basispar.init
        for (jj in 1:J){
            delta[[jj]] <- u.delta[ seq( Mj.index[jj,2], Mj.index[jj,3] ), 1]
        }
    }
    #--- OUTPUT
    return(delta)
}