todo-files/sof.katsuura.R

In jakobbossek/smoof: Single and Multi-Objective Optimization Test Functions

#' Katsuura function
#'
#' @template arg_dimensions
#FIXME: parameter meaning
#' @param d [\code{integer(1)}]\cr
#'   Parameter.
#' @template ret_smoof_single
# @export
#FIXME: do not export for now. There seems to be a problem
makeKatsuuraFunction = function(dimensions, d = 32) {
  #FIXME: type is convex, unimodal
  assertCount(dimensions, na.ok = FALSE)
  assertCount(d, na.ok = FALSE)

  force(d)

  global.opt.params = as.list(rep(0, dimensions))
  names(global.opt.params) = paste("x", seq(dimensions), sep = "")
  makeSingleObjectiveFunction(
    name = paste(dimensions, "-d Katsuura function", sep = ""),
    fn = function(x) {
      r = 1
      #FIXME: quick and dirty implementation. Make it more R like.
      #FIXME: see http://www.geocities.ws/eadorio/mvf.pdf for another definition -.-
      for (i in 1:(length(x) - 1)) {
        t = 0
        for (k in 1:d) {
          t = t + floor(2^k * x[i]) * 2^(-k)
        }
        r = r  + (1 + (i + 1) * t)
      }
      return(r)
    },
    par.set = makeNumericParamSet(
      len = dimensions,
      id = "x",
      lower = rep(0, dimensions),
      upper = rep(1, dimensions),
      vector = TRUE
    ),
    global.opt.params = global.opt.params,
    global.opt.value = 1
  )
}