R/rm_smooth_distribution.R

In sirt: Supplementary Item Response Theory Models

## File Name: rm_smooth_distribution.R
## File Version: 0.25

rm_smooth_distribution <- function( theta.k, pi.k, est.mean=FALSE,
            skillspace="normal", est.sigma=TRUE, sigma=NULL )
{
    m2 <- 0
    if ( est.mean ){
        m2 <- sum( theta.k * pi.k )
    }
    if (est.sigma){
        w2 <- sum( theta.k^2 * pi.k ) - m2^2
        sigma <- sqrt(w2)
    }
    if ( skillspace=="normal" ){
        pi.k <- sirt_dnorm_discrete(x=theta.k, mean=m2, sd=sigma)
    }
    res <- list( mu=m2, sigma=sigma, pi.k=pi.k)
    return(res)
}

rm.smooth.distribution <- rm_smooth_distribution