R/smooth.data.R

In fdasrvf: Elastic Functional Data Analysis

#' Smooth Functions
#'
#' This function smooths functions using standard box filter
#'
#' @param f matrix (\eqn{N} x \eqn{M}) of \eqn{M} functions with \eqn{N} samples
#' @param sparam number of times to run box filter
#' @return fo smoothed functions
#' @keywords srvf alignment
#' @references Srivastava, A., Wu, W., Kurtek, S., Klassen, E., Marron, J. S.,
#'  May 2011. Registration of functional data using fisher-rao metric,
#'  arXiv:1103.3817v2.
#' @references Tucker, J. D., Wu, W., Srivastava, A.,
#'  Generative Models for Function Data using Phase and Amplitude Separation,
#'  Computational Statistics and Data Analysis (2012), 10.1016/j.csda.2012.12.001.
#' @export
#' @examples
#' fo <- smooth.data(simu_data$f, 25)
smooth.data <- function(f,sparam){
    M = nrow(f)
    N = ncol(f)
    for (r in 1:sparam){
        for (i in 1:N){
            f[2:(M-1),i] = (f[1:(M-2),i]+2*f[2:(M-1),i] + f[3:M,i])/4
        }
    }
    return(f)
}