R/MultiTableTransform.R

In MultBiplotR: Multivariate Analysis Using Biplots in R

MultiTableTransform <- function(X, InitTransform="Standardize columns", dual=FALSE, CommonSD=TRUE){
  ng = length(X) #Number of groups

  # Common sd means that the standardization is made with an estimation of the common variance
  # This is so to be able to place scales on the variables that interpretable in all groups

  if (dual & CommonSD){
    Varnames=colnames(X[[1]])
    if (InitTransform=="Standardize columns"){
      nr=rep(0, ng)
      sd=NULL
      for (i in 1:ng){
        nr[i]=dim(X[[i]])[1]
        sd=rbind(sd,apply(X[[i]], 2, sd))
        X[[i]] = TransformIni(X[[i]],transform = "Column centering")
      }
      
      sds=sqrt(apply((diag(nr-1) %*% sd^2),2,sum)/sum(nr-1))
      for (i in 1:ng){
        X[[i]] = X[[i]] %*% diag(1/sds)
        colnames(X[[i]])=Varnames
      }
    }
  }
  else
    for (i in 1:ng){
      X[[i]] = TransformIni(X[[i]],InitTransform)}
  
  Res=list(X=X)
  Res$Dual=dual
  if (dual & CommonSD)
    Res$SD=sds
  
  return(Res)
}