R/CP2NuclearNormedCP.R

In DistatisR: DiSTATIS Three Way Metric Multidimensional Scaling

#' @title CP2NuclearNormedCP
#' @description Nuclear Norm normalizes a cube of cross-product matrices
#' @param CP3 A 3D array of cross-product matrices
#' @return The 3D array of the normalized cross-product matrices.
#' @examples 
#' \donttest{
#' D3 <- array(c(0, 1, 2, 1, 0, 1, 2, 1, 0,
#'               0, 3, 3, 3, 0, 3, 3, 3, 0), 
#'            dim = c(3, 3, 2))
#' CP2NuclearNormedCP(D3)         
#' }
#' 
#' @rdname CP2NuclearNormedCP
#' @export 
CP2NuclearNormedCP <-
  function(CP3) {
    # Transform a cube of CP into an MFA normed cube of CP
    CP3normed <- array(apply(CP3, 3, NuclearNormedCP), 
                       dim = dim(CP3))
    dimnames(CP3normed) <- dimnames(CP3)
    return(CP3normed)
  }