Kross-Kross algorithm for filling a matrix with the coordinates of another matrix

algorithm.R

A <- matrix(NA, nrow = 4, ncol = 7)

x <- function(A){
  total_pairs <- nrow(A) * ncol(A)
  rc <- matrix(NA, ncol = 2, nrow = total_pairs)
  k <- r <- c <- 1
  while (k <= total_pairs) {
   rc[k, 1] <- r
   rc[k, 2] <- c
   k <- k+1
   if(c >= ncol(A)){
     r <- r+1
     c <- 1
   } else {
     c <- c+1
   }
  }
  rc
}

x(A)