R/reglca_dpm_smoothing.R

In CDM: Cognitive Diagnosis Modeling

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

reglca_dpm_smoothing <- function( p.aj.xi, weights, nclasses, alpha, dpm_maxit=10, dpm_conv=1E-4 )
{
    freq_classes <- colSums( p.aj.xi * weights )
    # update vh
    iterate <- TRUE
    eps <- 1E-20
    iter <- 0
    vh <- rep(1,nclasses)
    while( iterate ){
        alpha0 <- alpha
        vh0 <- vh
        for (tt in 1:nclasses){
            vh[tt] <- freq_classes[tt] / ( sum( freq_classes[ seq(tt,nclasses) ] ) + alpha - 1 )
        }
        ind <- which( vh > 1 - eps )
        if ( length(ind)>0){
            vh[ seq( ind, nclasses) ] <- 1 - eps
        }
        # update alpha
        alpha <- ( 1 - nclasses ) / sum( log( 1 - vh[ seq(1, nclasses - 1 ) ] ) )
        iter <- iter + 1
        parm_change <- max( c( abs( alpha - alpha0 ), abs( vh - vh0 ) ))
        if ( iter==dpm_maxit ){ iterate <- FALSE }
        if ( parm_change < dpm_conv ){ iterate <- FALSE }
    }
    class_probs <- dpm_calc_probs( vh=vh )
    #--- output
    res <- list( alpha=alpha, class_probs=class_probs)
    return(res)
}