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MATH-1248 

Unnecessary allocations in "BigFraction".
Thanks to Chris Popp.
This commit is contained in:
Gilles 2015-07-11 14:54:43 +02:00
parent 0448161808
commit ae5d8f8a92
2 changed files with 103 additions and 12 deletions
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3
pom.xml
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@ -350,6 +350,9 @@
<contributor>
<name>Xiaogang Zhang</name>
</contributor>
<contributor>
<name>Chris Popp</name>
</contributor>
</contributors>
<dependencies>

112
src/main/java/org/apache/commons/math3/fraction/BigFraction.java
View File

@ -119,10 +119,10 @@ public class BigFraction
public BigFraction(BigInteger num, BigInteger den) {
MathUtils.checkNotNull(num, LocalizedFormats.NUMERATOR);
MathUtils.checkNotNull(den, LocalizedFormats.DENOMINATOR);
if (BigInteger.ZERO.equals(den)) {
if (den.signum() == 0) {
throw new ZeroException(LocalizedFormats.ZERO_DENOMINATOR);
}
if (BigInteger.ZERO.equals(num)) {
if (num.signum() == 0) {
numerator = BigInteger.ZERO;
denominator = BigInteger.ONE;
} else {
@ -135,7 +135,7 @@ public class BigFraction
}
// move sign to numerator
if (BigInteger.ZERO.compareTo(den) > 0) {
if (den.signum() == -1) {
num = num.negate();
den = den.negate();
}
@ -450,7 +450,7 @@ public class BigFraction
* @return the absolute value as a {@link BigFraction}.
*/
public BigFraction abs() {
return (BigInteger.ZERO.compareTo(numerator) <= 0) ? this : negate();
return (numerator.signum() == 1) ? this : negate();
}
/**
@ -467,6 +467,14 @@ public class BigFraction
*/
public BigFraction add(final BigInteger bg) throws NullArgumentException {
MathUtils.checkNotNull(bg);
if (numerator.signum() == 0) {
return new BigFraction(bg);
}
if (bg.signum() == 0) {
return this;
}
return new BigFraction(numerator.add(denominator.multiply(bg)), denominator);
}
@ -509,13 +517,17 @@ public class BigFraction
* @return a {@link BigFraction} instance with the resulting values.
* @throws NullArgumentException if the {@link BigFraction} is {@code null}.
*/
@Override
public BigFraction add(final BigFraction fraction) {
if (fraction == null) {
throw new NullArgumentException(LocalizedFormats.FRACTION);
}
if (ZERO.equals(fraction)) {
if (fraction.numerator.signum() == 0) {
return this;
}
if (numerator.signum() == 0) {
return fraction;
}
BigInteger num = null;
BigInteger den = null;
@ -527,6 +539,11 @@ public class BigFraction
num = (numerator.multiply(fraction.denominator)).add((fraction.numerator).multiply(denominator));
den = denominator.multiply(fraction.denominator);
}
if (num.signum() == 0) {
return ZERO;
}
return new BigFraction(num, den);
}
@ -596,7 +613,18 @@ public class BigFraction
* than {@code object}, 0 if they are equal.
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
@Override
public int compareTo(final BigFraction object) {
int lhsSigNum = numerator.signum();
int rhsSigNum = object.numerator.signum();
if (lhsSigNum != rhsSigNum) {
return (lhsSigNum > rhsSigNum) ? 1 : -1;
}
if (lhsSigNum == 0) {
return 0;
}
BigInteger nOd = numerator.multiply(object.denominator);
BigInteger dOn = denominator.multiply(object.numerator);
return nOd.compareTo(dOn);
@ -617,9 +645,12 @@ public class BigFraction
if (bg == null) {
throw new NullArgumentException(LocalizedFormats.FRACTION);
}
if (BigInteger.ZERO.equals(bg)) {
if (bg.signum() == 0) {
throw new MathArithmeticException(LocalizedFormats.ZERO_DENOMINATOR);
}
if (numerator.signum() == 0) {
return ZERO;
}
return new BigFraction(numerator, denominator.multiply(bg));
}
@ -662,13 +693,17 @@ public class BigFraction
* @throws NullArgumentException if the {@code fraction} is {@code null}.
* @throws MathArithmeticException if the fraction to divide by is zero
*/
@Override
public BigFraction divide(final BigFraction fraction) {
if (fraction == null) {
throw new NullArgumentException(LocalizedFormats.FRACTION);
}
if (BigInteger.ZERO.equals(fraction.numerator)) {
if (fraction.numerator.signum() == 0) {
throw new MathArithmeticException(LocalizedFormats.ZERO_DENOMINATOR);
}
if (numerator.signum() == 0) {
return ZERO;
}
return multiply(fraction.reciprocal());
}
@ -870,6 +905,9 @@ public class BigFraction
if (bg == null) {
throw new NullArgumentException();
}
if (numerator.signum() == 0 || bg.signum() == 0) {
return ZERO;
}
return new BigFraction(bg.multiply(numerator), denominator);
}
@ -883,7 +921,12 @@ public class BigFraction
* the {@code int} to multiply by.
* @return a {@link BigFraction} instance with the resulting values.
*/
@Override
public BigFraction multiply(final int i) {
if (i == 0 || numerator.signum() == 0) {
return ZERO;
}
return multiply(BigInteger.valueOf(i));
}
@ -898,6 +941,10 @@ public class BigFraction
* @return a {@link BigFraction} instance with the resulting values.
*/
public BigFraction multiply(final long l) {
if (l == 0 || numerator.signum() == 0) {
return ZERO;
}
return multiply(BigInteger.valueOf(l));
}
@ -911,12 +958,13 @@ public class BigFraction
* @return a {@link BigFraction} instance with the resulting values.
* @throws NullArgumentException if {@code fraction} is {@code null}.
*/
@Override
public BigFraction multiply(final BigFraction fraction) {
if (fraction == null) {
throw new NullArgumentException(LocalizedFormats.FRACTION);
}
if (numerator.equals(BigInteger.ZERO) ||
fraction.numerator.equals(BigInteger.ZERO)) {
if (numerator.signum() == 0 ||
fraction.numerator.signum() == 0) {
return ZERO;
}
return new BigFraction(numerator.multiply(fraction.numerator),
@ -931,6 +979,7 @@ public class BigFraction
*
* @return the negation of this fraction.
*/
@Override
public BigFraction negate() {
return new BigFraction(numerator.negate(), denominator);
}
@ -959,6 +1008,13 @@ public class BigFraction
* @return <tt>this<sup>exponent</sup></tt>.
*/
public BigFraction pow(final int exponent) {
if (exponent == 0) {
return ONE;
}
if (numerator.signum() == 0) {
return this;
}
if (exponent < 0) {
return new BigFraction(denominator.pow(-exponent), numerator.pow(-exponent));
}
@ -976,6 +1032,13 @@ public class BigFraction
* @return <tt>this<sup>exponent</sup></tt> as a <code>BigFraction</code>.
*/
public BigFraction pow(final long exponent) {
if (exponent == 0) {
return ONE;
}
if (numerator.signum() == 0) {
return this;
}
if (exponent < 0) {
return new BigFraction(ArithmeticUtils.pow(denominator, -exponent),
ArithmeticUtils.pow(numerator, -exponent));
@ -995,7 +1058,14 @@ public class BigFraction
* @return <tt>this<sup>exponent</sup></tt> as a <code>BigFraction</code>.
*/
public BigFraction pow(final BigInteger exponent) {
if (exponent.compareTo(BigInteger.ZERO) < 0) {
if (exponent.signum() == 0) {
return ONE;
}
if (numerator.signum() == 0) {
return this;
}
if (exponent.signum() == -1) {
final BigInteger eNeg = exponent.negate();
return new BigFraction(ArithmeticUtils.pow(denominator, eNeg),
ArithmeticUtils.pow(numerator, eNeg));
@ -1026,6 +1096,7 @@ public class BigFraction
*
* @return the reciprocal fraction.
*/
@Override
public BigFraction reciprocal() {
return new BigFraction(denominator, numerator);
}
@ -1040,7 +1111,12 @@ public class BigFraction
*/
public BigFraction reduce() {
final BigInteger gcd = numerator.gcd(denominator);
return new BigFraction(numerator.divide(gcd), denominator.divide(gcd));
if (BigInteger.ONE.compareTo(gcd) < 0) {
return new BigFraction(numerator.divide(gcd), denominator.divide(gcd));
} else {
return this;
}
}
/**
@ -1057,6 +1133,13 @@ public class BigFraction
if (bg == null) {
throw new NullArgumentException();
}
if (bg.signum() == 0) {
return this;
}
if (numerator.signum() == 0) {
return new BigFraction(bg.negate());
}
return new BigFraction(numerator.subtract(denominator.multiply(bg)), denominator);
}
@ -1096,13 +1179,17 @@ public class BigFraction
* @return a {@link BigFraction} instance with the resulting values
* @throws NullArgumentException if the {@code fraction} is {@code null}.
*/
@Override
public BigFraction subtract(final BigFraction fraction) {
if (fraction == null) {
throw new NullArgumentException(LocalizedFormats.FRACTION);
}
if (ZERO.equals(fraction)) {
if (fraction.numerator.signum() == 0) {
return this;
}
if (numerator.signum() == 0) {
return fraction.negate();
}
BigInteger num = null;
BigInteger den = null;
@ -1140,6 +1227,7 @@ public class BigFraction
}
/** {@inheritDoc} */
@Override
public BigFractionField getField() {
return BigFractionField.getInstance();
}