scripts/builtin/scaleApply.dml

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# Scale and center individual features in the input matrix (column wise.) using the input matrices.
# ---------------------------------------------------------------------------------------------
# NAME         TYPE      DEFAULT  MEANING
# ---------------------------------------------------------------------------------------------
# X            Matrix    ---      Input feature matrix
# Centering    Matrix    ---      The column means to subtract from X (not done if empty)
# ScaleFactor  Matrix    ---      The column scaling to multiply with X (not done if empty)
# ---------------------------------------------------------------------------------------------
# Y            Matrix    ---      Output feature matrix with K columns
# ---------------------------------------------------------------------------------------------

m_scaleApply = function(Matrix[Double] X, Matrix[Double] Centering, Matrix[Double] ScaleFactor) 
  return (Matrix[Double] Y) 
{
  centered = ifelse(nrow(Centering) > 0 & ncol(Centering) > 0, X - Centering, X)
  Y = ifelse(nrow(ScaleFactor) > 0 & ncol(ScaleFactor) > 0,  centered / ScaleFactor, centered)
}