R/latin.R

In gexp: Generator of Experiments

###########################################################################
#
# This function was copied of material avaliable in the following link (Esta funcao foi copiada do material disponivel no seguinte link)
# http://www.stat.wisc.edu/courses/st572-larget/Spring2007/handouts17-4.pdf
#
###########################################################################
latin <- function(n, 
                  levelss = NULL, 
                  nrand = 20) {

  if(is.null(levelss)){
    levelss <- LETTERS[1:n]
  }

  x = matrix(levelss, 
             n, 
             n)
  x = t(x)
  for (i in 2:n) x[i, ] = x[i, 
                            c(i:n, 1:(i - 1))]
  if (nrand > 0) {
    for (i in 1:nrand) {
      x = x[sample(n), ]
      x = x[, sample(n)]
    }
  }
  x
}