@HiveDecimalVersionV1
  public HiveDecimal negate() {
    if (fastSignum() == 0) {
      return this;
    }
    HiveDecimal result = new HiveDecimal(this);
    result.fastNegate();
    return result;
  }
Reverse the sign of a decimal.
<p>
@return Returns a new decimal with the sign flipped.  When the value is 0, the current
object is returned.
storage-api/src/java/org/apache/hadoop/hive/common/type/HiveDecimal.java