R/fastMedian.R

In aalfons/ccaPP: (Robust) Canonical Correlation Analysis via Projection Pursuit

# ----------------------
# Author: Andreas Alfons
#         KU Leuven
# ----------------------

#' Fast implementation of the median
#'
#' Compute the sample median with a fast C++ implementation.
#'
#' @param x  a numeric vector.
#'
#' @return The sample median.
#'
#' @note Functionality for removing observations with missing values is
#' currently not implemented.
#'
#' @author Andreas Alfons
#'
#' @seealso \code{\link{fastMAD}}, \code{\link[stats]{median}}
#'
#' @examples
#' set.seed(1234)  # for reproducibility
#' x <- rnorm(100)
#' fastMedian(x)
#'
#' @keywords multivariate robust
#'
#' @importFrom Rcpp evalCpp
#' @useDynLib ccaPP, .registration = TRUE
#' @export

fastMedian <- function(x) {
    # initializations
    x <- as.numeric(x)
    if(length(x) == 0) return(NA)  # zero length vector
    # call C++ function
    .Call("R_fastMedian", R_x=x, PACKAGE="ccaPP")
}