R/fasterscale.R

In zouyuxin/fasterscale: Methods for Efficiently Centering and Scaling Matrices

#' @title Fast Centering and Scaling of Matrices
#'
#' @description Does the same thing as \code{scale(x)}, but faster.
#'
#' @details Uses \code{\link[matrixStats]{colSds}} from teh \code{matrixStats} pacakge.
#'
#' @param x A numeric matrix; \code{is.matrix(x)} should be \code{TRUE}. 
#' 
#' @return A matrix in which the column are centered to have zero mean, and they are also scaled to have standard deviation of 1.
#' 
#' @importFrom matrixStats colSds
#'
#' @export
scale_faster = function(x){
  a = colMeans(x)
  b = matrixStats::colSds(x)
  x = t(t(x) - a)
  x = t(t(x)/b)
  return(x)
}