# Rajarshi Guha <rajarshi@presidency.com>
# 2/2/05

# rescale a vector so that it lies between
# the specified minimum and maximum
rescale <- function(x, newrange) {
    if (!is.numeric(x) || !is.numeric(newrange)){
        stop("Must supply numerics for the x and the new scale")
    }
    if (length(newrange) != 2) {
        stop("newrange must be a numeric vector with 2 elements")
    }
    newmin <- min(newrange)
    newmax <- max(newrange)

    oldrange <- range(x)
    if (oldrange[1] == oldrange[2]) {
        stop("The supplied vector is a constant. Cannot rescale")
    }
    y <- (newmax - newmin) / (oldrange[2] - oldrange[1])
    newmin + (x - oldrange[1]) * y
}