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Optimizations
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@safris
safris committed Jul 7, 2023
1 parent 331b71e commit da02eb4
Showing 1 changed file with 69 additions and 58 deletions.
127 changes: 69 additions & 58 deletions src/main/java/org/libj/math/SafeMath.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,13 +22,12 @@
import java.math.BigInteger;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.HashMap;

import org.libj.lang.BigDecimals;

import ch.obermuhlner.math.big.BigDecimalMath;

// FIXME: Add Assertions.*

/**
* Utility that supplements functions in {@link Math} by providing compiler-safe implementations for common math functions.
* Compiler-safe methods are those that are linked directly by the compiler based on exact argument match.
Expand Down Expand Up @@ -1473,6 +1472,21 @@ public static double toDegrees(final double a) {
return StrictMath.toDegrees(a);
}

private static final BigDecimal d180 = BigDecimal.valueOf(180);
private static final BigInteger i180 = BigInteger.valueOf(180);

private static final HashMap<MathContext,BigDecimal> mathContextTo180OverPi = new HashMap<MathContext,BigDecimal>() {
@Override
public BigDecimal get(final Object key) {
BigDecimal value = super.get(key);
final MathContext mc = (MathContext)key;
if (value == null)
super.put(mc, value = d180.divide(BigDecimals.PI, mc));

return value;
}
};

/**
* Converts an angle measured in radians to an approximately equivalent angle measured in degrees. The conversion from radians to
* degrees is generally inexact; users should <i>not</i> expect {@code cos(toRadians(90.0))} to exactly equal {@code 0.0}.
Expand All @@ -1484,8 +1498,7 @@ public static double toDegrees(final double a) {
* @throws NullPointerException If {@code a} or {@code mc} is null.
*/
public static BigDecimal toDegrees(final BigDecimal a, final MathContext mc) {
// FIXME: 180 / PI should be cached based on mc
return a.multiply(BigDecimal.valueOf(180), mc).divide(BigDecimals.PI, mc);
return a.multiply(mathContextTo180OverPi.get(mc));
}

/**
Expand All @@ -1499,8 +1512,7 @@ public static BigDecimal toDegrees(final BigDecimal a, final MathContext mc) {
* @throws NullPointerException If {@code a} or {@code mc} is null.
*/
public static BigDecimal toDegrees(final BigInteger a, final MathContext mc) {
// FIXME: 180 / PI should be cached based on mc
return new BigDecimal(a.multiply(BigInteger.valueOf(180)), mc).divide(BigDecimals.PI, mc);
return new BigDecimal(a.multiply(i180), mc).divide(BigDecimals.PI, mc);
}

/**
Expand All @@ -1525,8 +1537,7 @@ public static double toRadians(final double a) {
* @throws NullPointerException If {@code a} or {@code mc} is null.
*/
public static BigDecimal toRadians(final BigDecimal a, final MathContext mc) {
// FIXME: PI / 180 should be cached based on mc
return a.divide(BigDecimal.valueOf(180), mc).multiply(BigDecimals.PI, mc);
return a.divide(mathContextTo180OverPi.get(mc), mc);
}

/**
Expand Down Expand Up @@ -3900,9 +3911,9 @@ public static BigDecimal min(final BigDecimal a, final BigDecimal b) {
* @throws IllegalArgumentException If {@code a} of {@code b} is negative.
* @see <a href="http://en.wikipedia.org/wiki/Binary_GCD_algorithm">Binary GCD algorithm</a>
*/
public static byte gcd(byte a, byte b) {
assertNotNegative(a, "a must be positive: %d", a);
assertNotNegative(b, "b must be positive: %d", b);
public static byte gcd(final byte a, final byte b) {
assertNotNegative(a, () -> "a must be positive: " + a);
assertNotNegative(b, () -> "b must be positive: " + b);

if (a == 0)
return b;
Expand All @@ -3911,20 +3922,21 @@ public static byte gcd(byte a, byte b) {
return a;

final int a2 = Integer.numberOfTrailingZeros(a);
a >>= a2;
byte a1 = a;
a1 >>= a2;

final int b2 = Integer.numberOfTrailingZeros(b);
b >>= b2;

while (a != b) {
a -= b;
final int minDeltaOrZero = a & (a >> (Byte.SIZE - 1));
a -= minDeltaOrZero << 1;
b += minDeltaOrZero;
a >>= Integer.numberOfTrailingZeros(a);
byte b1 = b;
b1 >>= b2;

for (int minDeltaOrZero; a1 != b1; a1 >>= Integer.numberOfTrailingZeros(a1)) { // [N]
a1 -= b1;
minDeltaOrZero = a1 & (a1 >> (Byte.SIZE - 1));
a1 -= minDeltaOrZero << 1;
b1 += minDeltaOrZero;
}

return a <<= (a2 < b2 ? a2 : b2);
return a1 <<= (a2 < b2 ? a2 : b2);
}

/**
Expand All @@ -3936,9 +3948,9 @@ public static byte gcd(byte a, byte b) {
* @throws IllegalArgumentException If {@code a} of {@code b} is negative.
* @see <a href="http://en.wikipedia.org/wiki/Binary_GCD_algorithm">Binary GCD algorithm</a>
*/
public static short gcd(short a, short b) {
assertNotNegative(a, "a must be positive: %d", a);
assertNotNegative(b, "b must be positive: %d", b);
public static short gcd(final short a, final short b) {
assertNotNegative(a, () -> "a must be positive: " + a);
assertNotNegative(b, () -> "b must be positive: " + b);

if (a == 0)
return b;
Expand All @@ -3947,20 +3959,21 @@ public static short gcd(short a, short b) {
return a;

final int a2 = Integer.numberOfTrailingZeros(a);
a >>= a2;
short a1 = a;
a1 >>= a2;

final int b2 = Integer.numberOfTrailingZeros(b);
b >>= b2;

while (a != b) {
a -= b;
final int minDeltaOrZero = a & (a >> (Short.SIZE - 1));
a -= minDeltaOrZero << 1;
b += minDeltaOrZero;
a >>= Integer.numberOfTrailingZeros(a);
short b1 = b;
b1 >>= b2;

for (int minDeltaOrZero; a1 != b1; a1 >>= Integer.numberOfTrailingZeros(a1)) { // [N]
a1 -= b1;
minDeltaOrZero = a1 & (a1 >> (Short.SIZE - 1));
a1 -= minDeltaOrZero << 1;
b1 += minDeltaOrZero;
}

return a <<= (a2 < b2 ? a2 : b2);
return a1 <<= (a2 < b2 ? a2 : b2);
}

/**
Expand All @@ -3972,9 +3985,9 @@ public static short gcd(short a, short b) {
* @throws IllegalArgumentException If {@code a} of {@code b} is negative.
* @see <a href="http://en.wikipedia.org/wiki/Binary_GCD_algorithm">Binary GCD algorithm</a>
*/
public static int gcd(int a, int b) {
assertNotNegative(a, "a must be positive: %d", a);
assertNotNegative(b, "b must be positive: %d", b);
public static int gcd(final int a, final int b) {
assertNotNegative(a, () -> "a must be positive: " + a);
assertNotNegative(b, () -> "b must be positive: " + b);

if (a == 0)
return b;
Expand All @@ -3983,20 +3996,19 @@ public static int gcd(int a, int b) {
return a;

final int a2 = Integer.numberOfTrailingZeros(a);
a >>= a2;
int a1 = a >> a2;

final int b2 = Integer.numberOfTrailingZeros(b);
b >>= b2;
int b1 = b >> b2;

while (a != b) {
a -= b;
final int minDeltaOrZero = a & (a >> (Integer.SIZE - 1));
a -= minDeltaOrZero << 1;
b += minDeltaOrZero;
a >>= Integer.numberOfTrailingZeros(a);
for (int minDeltaOrZero; a1 != b1; a1 >>= Integer.numberOfTrailingZeros(a1)) { // [N]
a1 -= b1;
minDeltaOrZero = a1 & (a1 >> (Integer.SIZE - 1));
a1 -= minDeltaOrZero << 1;
b1 += minDeltaOrZero;
}

return a << Math.min(a2, b2);
return a1 <<= (a2 < b2 ? a2 : b2);
}

/**
Expand All @@ -4008,9 +4020,9 @@ public static int gcd(int a, int b) {
* @throws IllegalArgumentException If {@code a} of {@code b} is negative.
* @see <a href="http://en.wikipedia.org/wiki/Binary_GCD_algorithm">Binary GCD algorithm</a>
*/
public static long gcd(long a, long b) {
assertNotNegative(a, "a must be positive: %d", a);
assertNotNegative(b, "b must be positive: %d", b);
public static long gcd(final long a, final long b) {
assertNotNegative(a, () -> "a must be positive: " + a);
assertNotNegative(b, () -> "b must be positive: " + b);

if (a == 0)
return b;
Expand All @@ -4019,20 +4031,19 @@ public static long gcd(long a, long b) {
return a;

final int a2 = Long.numberOfTrailingZeros(a);
a >>= a2;
long a1 = a >> a2;

final int b2 = Long.numberOfTrailingZeros(b);
b >>= b2;
long b1 = b >> b2;

while (a != b) {
a -= b;
final long minDeltaOrZero = a & (a >> (Long.SIZE - 1L));
a -= minDeltaOrZero << 1;
b += minDeltaOrZero;
a >>= Long.numberOfTrailingZeros(a);
for (long minDeltaOrZero; a1 != b1; a1 >>= Long.numberOfTrailingZeros(a1)) { // [N]
a1 -= b1;
minDeltaOrZero = a1 & (a1 >> (Long.SIZE - 1));
a1 -= minDeltaOrZero << 1;
b1 += minDeltaOrZero;
}

return a << Math.min(a2, b2);
return a1 << Math.min(a2, b2);
}

private SafeMath() {
Expand Down

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