public static double round(double d) {
    if (d > 0.0) {
      return (double) ((long) (d + 0.5d));
    } else {
      return (double) ((long) (d - 0.5d));
    }
  }
Math expression evaluation helper functions.
Some of these are referenced from ColumnUnaryFunc.txt.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/MathExpr.java