XenoAmess commented on a change in pull request #83:
URL: https://github.com/apache/commons-numbers/pull/83#discussion_r476632088
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File path:
commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/Fraction.java
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@@ -775,19 +778,45 @@ public Fraction divide(Fraction value) {
*/
@Override
public Fraction pow(final int exponent) {
+ if (exponent == 1) {
+ return this;
+ }
if (exponent == 0) {
return ONE;
}
- if (isZero()) {
- return ZERO;
+ if (exponent == -1) {
+ return this.reciprocal();
}
-
- if (exponent < 0) {
- return new Fraction(ArithmeticUtils.pow(denominator, -exponent),
- ArithmeticUtils.pow(numerator, -exponent));
+ if (this.denominator == 0) {
+ if (exponent > 0) {
+ throw new
ArithmeticException(STRING_THE_DENOMINATOR_MUST_NOT_BE_ZERO);
+ } else {
+ return ZERO;
+ }
+ }
+ if (this.numerator == 0) {
+ if (exponent < 0) {
+ throw new
ArithmeticException(STRING_THE_DENOMINATOR_MUST_NOT_BE_ZERO);
+ } else {
+ return ZERO;
+ }
}
- return new Fraction(ArithmeticUtils.pow(numerator, exponent),
- ArithmeticUtils.pow(denominator, exponent));
+ if (exponent > 0) {
+ return new Fraction(
+ ArithmeticUtils.pow(this.numerator, exponent),
+ ArithmeticUtils.pow(this.denominator, exponent)
+ );
+ }
+ if (exponent == Integer.MIN_VALUE) {
+ return new Fraction(
+ ArithmeticUtils.pow(this.denominator, Integer.MAX_VALUE) *
this.denominator,
Review comment:
@aherbert
No need to use Math.multipyExact here.
Because:
If this.denominator be 0,1,or -1, then it will never overflow.
Other wise, any other int do pow with Integer.MAX_VALUE will overflow, it
will overflow in ArithmeticUtils.pow, and thus before we do the raw multiply.
So it is a tricky but correct implement.
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