R/norm1.R

In vguillemot/sparseMCA:

#' Compute the l1 norm of a vector.
#'
#' @param u A vector of numerics
#' @return The \eqn{l_1} norm of \eqn{u}: \eqn{\sum_i w_i |u_i|}.
#' @examples
#' norm1(c(0, 0,-0.5, 0.5))
#' @export
norm1 <- function(u) sum(abs(u))