R/interleaveMatrixWithItself.R

In stnava/ANTsR: ANTs in R: Quantification Tools for Biomedical Images

#' Simple interleaveMatrixWithItself function.
#'
#' Replicate columns of input matrix n times as neighbors of columns in
#' original matrix.
#'
#'
#' @param x input matrix
#' @param n number of interleaves
#' @return matrix is output
#' @author Avants BB
#' @examples
#'
#' mat <- replicate(100, rnorm(20))
#' wmat <- interleaveMatrixWithItself(mat, 5)
#'
#' @export interleaveMatrixWithItself
interleaveMatrixWithItself <- function(x, n = 1) {
  if (nargs() == 0) {
    print(args(interleaveMatrixWithItself))
    return(1)
  }
  nc <- ncol(x)
  nr <- nrow(x)
  xi <- matrix(rep(0, nr * nc * n), nrow = nr)
  colnames(xi) <- paste("V", 1:ncol(xi))
  colnamesxi <- colnames(xi)
  colnamesx <- colnames(x)
  j <- 1
  for (i in 1:ncol(x)) {
    xi[, j:(j + n - 1)] <- x[, i]
    colnamesxi[j:(j + n - 1)] <- paste(colnamesx[i], 1:n, sep = "")
    j <- j + n
  }
  colnames(xi) <- colnamesxi
  return(xi)
}