R/quadratic.weights.R

In autoFC: Automatic Construction of Forced-Choice Tests

quadratic.weights <- function (categ) {
  q <- length(categ)
  weights <- diag(q)
  if (is.numeric(categ)) {
    categ.vec <- sort(categ)
  }
  else {
    categ.vec <- 1:length(categ)
  }
  xmin <- min(categ.vec)
  xmax <- max(categ.vec)
  for (k in 1:q) {
    for (l in 1:q) {
      weights[k, l] <- 1 - (categ.vec[k] - categ.vec[l])^2/(xmax - xmin)^2
    }
  }
  return(weights)
}