R code for "vincentize", originally written by Paul Lemmens, gotten from https://stat.ethz.ch/pipermail/r-help/2003-May/034272.html

vincentize.R

vincentize <- function(data, bins)
{
        if ( length(data) < 2 )
                {
                            stop("The data is really short. Is that ok?");
    }

    if ( bins < 2 )
            {
                        stop("A number of bins smaller than 2 just really isn't useful");
        }

        if ( bins > length(data) )
                {
                            stop("This is really unusual, although perhaps possible. If you really know what you're doing, maybe you should disable this check!?.");
                                    }        
        ret <- c();
            for ( i in 1:length(data))
                    {
                                rt <- data[i];
                b <- 0;
                        while ( b < bins )
                                    {
                                                    ret <- c(ret, rt);
                            b <- b+1;
                                    }
                    }

            ret;
}


binify <- function(data, bins, n)
{
        if ( bins < 2 )
                {
                            stop("Number of bins is smaller than 2. Nothing to split, exiting.");
    }

    if ( length(data) < 2 )
            {
                        stop("The length of the data is really short. Is that ok?");
        }

        if ( bins * n != length(data) )
                {
                            stop("Cannot construct bins of equal length.");
            }

        t(array(data, c(n,bins)));
}

mean.bins <- function(data)
{
        # For the vincentizing procedures in vincentize() and binify(),
        # it made sense to check the data array/vector/matrix. Here,
        # we now just need to check that data is a matrix.
        if ( !is.matrix(data) )
                {
                            stop("The data is not in matrix form.");
    }

    means <- c();
        bins <- dim(data)[1];
        for (i in 1:bins)
                {
                            means <- c(means, mean(data[i,]));
            }

            # return a vector of means.
            means;
}

bins.factor <- function(data, bins)
{
        if ( !is.data.frame(data) )
                {
                            stop("data is not a data frame.");
    }

    source('Ratcliff.r', local=TRUE);
        subject.bin.means <- c();

        attach(data);
            l <- levels(Cond);
            for ( i in 1:length(l) )
                    {
                                cat("Calculating bins for factor level ", l[i], ".\n", sep="");
                    flush.console();

                            data <- RT[Cond == l[i]];
                            data <- sort(data);

                                    n <- length(data);
                                    data.vincent <- vincentize(data,bins);
                                            data.vincent.bins <- binify(data.vincent, bins, n);
                                            bin.means <- mean.bins(data.vincent.bins);

                                                    # FAILING TEST.
                                                    mean.orig <- mean(data);
                                                    mean.b <- mean(bin.means);
#                                                            if ( mean.b != mean.orig )
                                                                if (identical(all.equal(mean.b, mean.org, tolerance=.Machine$double.eps),FALSE)
                                                                        {
                                                                                        #cat("mean.b\n", str(mean.b), "mean.orig\n", str(mean.orig)); 
                                                                            flush.console;
                                                                                        detach(data);
                                                                                        stop("Something went wrong calculating the bins: means do not equal.");
                                                                                                }       
                                                            subject.bin.means <- c(subject.bin.means, bin.means);
                                                                }
                detach(data);

                if ( !length(subject.bin.means) == bins*length(l) )
                        {
                                    stop("Inappropriate number of means calculated.");
                    }
                    else
                            {
                                        subject.bin.means
                    }
}