Fraction: efficient divide by integer
diff --git a/commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/Fraction.java b/commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/Fraction.java
index 5eb3beb..d424045 100644
--- a/commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/Fraction.java
+++ b/commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/Fraction.java
@@ -595,6 +595,7 @@
// knuth 4.5.1
// Make sure we don't overflow unless the result *must* overflow.
+ // (see multiply(Fraction) using value / 1 as the argument).
final int d2 = ArithmeticUtils.gcd(value, denominator);
return new Fraction(Math.multiplyExact(numerator, value / d2),
denominator / d2);
@@ -641,7 +642,13 @@
return ZERO;
}
// Multiply by reciprocal
- return multiply(new Fraction(1, value));
+
+ // knuth 4.5.1
+ // Make sure we don't overflow unless the result *must* overflow.
+ // (see multiply(Fraction) using 1 / value as the argument).
+ final int d1 = ArithmeticUtils.gcd(numerator, value);
+ return new Fraction(numerator / d1,
+ Math.multiplyExact(denominator, value / d1));
}
/**
