R/plotDevianceTAM.R

In TAM: Test Analysis Modules

## File Name: plotDevianceTAM.R
## File Version: 9.111


plotDevianceTAM <- function ( tam.obj, omitUntil=1, reverse=TRUE,
            change=TRUE)
{
    stopifnot(inherits(tam.obj, c("tam.mml","tam.mml.2pl","tam.mml.mfr","tam.mml.3pl","tamaan")) )

    devhistory <- tam.obj$deviance.history
    if(omitUntil>0)  {
        devChange <- devhistory[-c(1:omitUntil),2]
    } else {
        devChange <- devhistory[,2]
    }
    if ( change ){
        devChange <- diff(devChange)
        ylab1 <- "Deviance Change"
    } else {
        ylab1 <- "Deviance"
    }

    if(reverse){
        devChange <- -devChange
    }
    devChange <- data.frame ( nr=omitUntil + 1:length(devChange), devChange)
    xm <- ceiling( max(devChange[,1])/10 )*10
    xt <- NULL
    for ( i in c( 1:30 ) ){
        xt <- c ( xt, (xm/10) %% i==0 )
    }
    xt <- max ( which ( xt ) )
    cex <- 0.85 - ( length(devChange[,1]) / 1000 )
    if ( cex < 0.40 ){
        cex <- 0.40
    }
    graphics::plot ( devChange[,1], devChange[,2], type="o",
                main="Deviance Change Plot", xlab="Iteration",
                xlim=c(min(devChange[,1]),max(devChange[,1])),  xaxp=c(0,xm,xt),
                ylab=ylab1, pch=20, cex=cex, lwd=0.75 )
    graphics::abline( a=0, b=0 )
    dcr <- devChange[devChange[,2]<0,]
    graphics::points( dcr[,1], dcr[,2], pch=20, cex=cex, col="red")
}