scripts/builtin/frequencyEncodeApply.dml

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

# frequency code apply
#
# INPUT:
# -------------------------------------------------------------------------------------
# X          dataset x
# freqCount  the frequency counts for the different categoricals
# -------------------------------------------------------------------------------------
#
# OUTPUT:
# -----------------------------------------------------------------------------------------
# X          categorical columns are replaced with their frequencies given
# -----------------------------------------------------------------------------------------


m_frequencyEncodeApply = function(Matrix[Double] X, Matrix[Double] freqCount)
return (Matrix[Double] X) {

 parfor(i in 1:ncol(X))
  {
    if(sum(freqCount[i]) > 0)
    {
      Y = replace(target=X[, i], pattern=NaN, replacement=1)
      idx = min(ncol(freqCount), max(Y))
      valueCount = freqCount[i, 1:idx]
      resp = matrix(0, nrow(Y), idx)
      resp = (resp + t(seq(1, idx))) == Y
      resp = resp * valueCount
      X[, i] = rowSums(resp)
    }
  }
}