R/rm_center_vector.R

In sirt: Supplementary Item Response Theory Models

## File Name: rm_center_vector.R
## File Version: 0.09

rm_center_vector <- function( vec, center_type, do_log=FALSE )
{
    # log metric
    if (do_log){
        vec <- log(vec)
    }
    #--- center_type=1
    if ( center_type==1){
        RR <- length(vec)
        vec[RR] <- - sum( vec[-RR] )
    }
    #--- center_type=2
    if ( center_type==2){
        vec <- vec - mean(vec)
    }
    # reconvert to exp metric
    if (do_log){
        vec <- exp(vec)
    }
    #--- output
    return(vec)
}