scripts/builtin/scaleApply.dml

#-------------------------------------------------------------
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#-------------------------------------------------------------

# This function scales and center individual features in the input matrix (column wise.) using the input matrices.
#
# INPUT:
# ------------------------------------------------------------------------------------------
# X            Input feature matrix
# Centering    The column means to subtract from X (not done if empty)
# ScaleFactor  The column scaling to multiply with X (not done if empty)
# ------------------------------------------------------------------------------------------
#
# OUTPUT:
# ------------------------------------------------------------------------------------
# Y     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)
  if(nrow(ScaleFactor) > 0 & ncol(ScaleFactor) > 0)
    Y = centered / ScaleFactor
  else Y = centered
}