R/latinRand.R

In randomizationInference: Flexible Randomization-Based Inference

# Random isomorphic Latin square assignments

latinRand <- function(w, nrand, row, col) {
  # formatting
  if (sum(factor(w) == w) > 0) w <- data.matrix(w)
  if (ncol(w) == 1) w <- as.vector(w)
  # random isomorphic assignments
  if (is.vector(w)) {
    n <- length(unique(w))
    rowperm <- replicate(nrand, rep(c(1, sample(2:n)), n))
    colperm <- replicate(nrand, as.vector(matrix(rep(sample(1:n), n), nrow = n, ncol = n, byrow = TRUE)))
    lapply(1:nrand, function(j) w[order(col, row)][order(colperm[, j], rowperm[, j])])
  } else {
    n <- length(unique(w[, 1]))
    rowperm <- replicate(nrand, rep(c(1, sample(2:n)), n))
    colperm <- replicate(nrand, as.vector(matrix(rep(sample(1:n), n), nrow = n, ncol = n, byrow = TRUE)))
    lapply(1:nrand, function(j) w[order(col, row), ][order(colperm[, j], rowperm[, j]), ])
  }
}