public double reduce(String numericColumnName,NumericReduceFunction function){
  Column column=column(numericColumnName);
  return function.reduce(column.toDoubleArray());
}

public double reduce ( String numericColumnName , NumericReduceFunction function ) { Column column = column ( numericColumnName ) ; return function . reduce ( column . toDoubleArray ( ) ) ; }
returns the result of applying the given function to the specified column
