R/plot.history.R

In BRugs: Interface to the 'OpenBUGS' MCMC Software

"plotHistory" <-
function(node, plot = TRUE, colour = c("red", "blue", "green", "yellow", "black"), 
    main = NULL, xlab = "iteration", ylab = "", ...)
#   Plot history for single component of OpenBUGS name
{
    sM <- samplesMonitors(node)
    if(length(sM) > 1 || sM != node)
        stop("node must be a scalar variable from the model, for arrays use samplesHistory")
    nodeName <- sQuote(node)
    sampleSize <- samplesSize(node)
    sample <- samplesSample(node)
    end <- min(c(modelIteration(), samplesGetEnd()))
    thin <- samplesGetThin()
    numChains <- samplesGetLastChain() - samplesGetFirstChain() + 1
    sampleSize <- sampleSize %/% numChains
    beg <- end - (sampleSize - 1) * thin
    beg <- beg %/% thin
    end <- end %/% thin
    x <- (beg:end) * thin
    y <- matrix(sample, ncol = numChains)
    if(plot){
        plot(x, y[,1], ylim = range(sample), type = "n", 
            main = if(is.null(main)) nodeName else main, 
            xlab = xlab , ylab = ylab, ...)
        for(chain in 1:numChains){
            lines(x, y[,chain], col = colour[chain], ...)
        }
        invisible(y)
    }
    else return(y)
}