public void testCeilingPowerOfTwo() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
BigInteger result = BigIntegerMath.ceilingPowerOfTwo(x);
assertTrue(BigIntegerMath.isPowerOfTwo(result));
assertTrue(result.compareTo(x) >= 0);
assertTrue(result.compareTo(x.add(x)) < 0);
}
}
public void testFloorPowerOfTwo() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
BigInteger result = BigIntegerMath.floorPowerOfTwo(x);
assertTrue(BigIntegerMath.isPowerOfTwo(result));
assertTrue(result.compareTo(x) <= 0);
assertTrue(result.add(result).compareTo(x) > 0);
}
}
// Relies on the correctness of log2(BigInteger, {HALF_UP,HALF_DOWN}).
public void testLog2HalfEven() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int halfEven = BigIntegerMath.log2(x, HALF_EVEN);
// Now figure out what rounding mode we should behave like (it depends if FLOOR was
// odd/even).
boolean floorWasEven = (BigIntegerMath.log2(x, FLOOR) & 1) == 0;
assertEquals(BigIntegerMath.log2(x, floorWasEven ? HALF_DOWN : HALF_UP), halfEven);
}
}
// Relies on the correctness of sqrt(BigInteger, {HALF_UP,HALF_DOWN}).
@GwtIncompatible // TODO
public void testSqrtHalfEven() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
BigInteger halfEven = BigIntegerMath.sqrt(x, HALF_EVEN);
// Now figure out what rounding mode we should behave like (it depends if FLOOR was
// odd/even).
boolean floorWasOdd = BigIntegerMath.sqrt(x, FLOOR).testBit(0);
assertEquals(BigIntegerMath.sqrt(x, floorWasOdd ? HALF_UP : HALF_DOWN), halfEven);
}
}
// Depends on the correctness of BigIntegerMath.factorial
private static void runBinomialTest(int firstN, int lastN) {
for (int n = firstN; n <= lastN; n++) {
for (int k = 0; k <= n; k++) {
BigInteger expected =
BigIntegerMath.factorial(n)
.divide(BigIntegerMath.factorial(k))
.divide(BigIntegerMath.factorial(n - k));
assertEquals(expected, BigIntegerMath.binomial(n, k));
}
}
}
// Relies on the correctness of isPowerOfTwo(BigInteger).
public void testLog2Exact() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
// We only expect an exception if x was not a power of 2.
boolean isPowerOf2 = BigIntegerMath.isPowerOfTwo(x);
try {
assertEquals(x, ZERO.setBit(BigIntegerMath.log2(x, UNNECESSARY)));
assertTrue(isPowerOf2);
} catch (ArithmeticException e) {
assertFalse(isPowerOf2);
}
}
}
// Relies on the correctness of log10(BigInteger, FLOOR).
@GwtIncompatible // TODO
public void testLog10Exact() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int logFloor = BigIntegerMath.log10(x, FLOOR);
boolean expectSuccess = TEN.pow(logFloor).equals(x);
try {
assertEquals(logFloor, BigIntegerMath.log10(x, UNNECESSARY));
assertTrue(expectSuccess);
} catch (ArithmeticException e) {
assertFalse(expectSuccess);
}
}
}
// Relies on the correctness of sqrt(BigInteger, FLOOR).
@GwtIncompatible // TODO
public void testSqrtExact() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
BigInteger floor = BigIntegerMath.sqrt(x, FLOOR);
// We only expect an exception if x was not a perfect square.
boolean isPerfectSquare = floor.pow(2).equals(x);
try {
assertEquals(floor, BigIntegerMath.sqrt(x, UNNECESSARY));
assertTrue(isPerfectSquare);
} catch (ArithmeticException e) {
assertFalse(isPerfectSquare);
}
}
}
public void testBinomialOutside() {
for (int n = 0; n <= 50; n++) {
try {
BigIntegerMath.binomial(n, -1);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
try {
BigIntegerMath.binomial(n, n + 1);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
public void testFactorial() {
for (int i = 0; i <= DoubleMath.MAX_FACTORIAL; i++) {
double actual = BigIntegerMath.factorial(i).doubleValue();
double result = DoubleMath.factorial(i);
assertEquals(actual, result, Math.ulp(actual));
}
}
@GwtIncompatible // TODO
public void testConstantSqrt2PrecomputedBits() {
assertEquals(
BigIntegerMath.sqrt(
BigInteger.ZERO.setBit(2 * BigIntegerMath.SQRT2_PRECOMPUTE_THRESHOLD + 1), FLOOR),
BigIntegerMath.SQRT2_PRECOMPUTED_BITS);
}
public void testFactorialNegative() {
try {
BigIntegerMath.factorial(-1);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
public void testCeilingPowerOfTwoZero() {
try {
BigIntegerMath.ceilingPowerOfTwo(BigInteger.ZERO);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
public void testFactorial() {
BigInteger expected = BigInteger.ONE;
for (int i = 1; i <= 200; i++) {
expected = expected.multiply(BigInteger.valueOf(i));
assertEquals(expected, BigIntegerMath.factorial(i));
}
}
@GwtIncompatible // TODO
@AndroidIncompatible // slow
public void testDivNonZeroExact() {
boolean isAndroid = System.getProperties().getProperty("java.runtime.name").contains("Android");
for (BigInteger p : NONZERO_BIGINTEGER_CANDIDATES) {
for (BigInteger q : NONZERO_BIGINTEGER_CANDIDATES) {
if (isAndroid && p.equals(BAD_FOR_ANDROID_P) && q.equals(BAD_FOR_ANDROID_Q)) {
// https://code.google.com/p/android/issues/detail?id=196555
continue;
}
if (isAndroid && p.equals(BAD_FOR_GINGERBREAD_P) && q.equals(BAD_FOR_GINGERBREAD_Q)) {
// Works fine under Marshmallow, so I haven't filed a bug.
continue;
}
boolean dividesEvenly = p.remainder(q).equals(ZERO);
try {
BigInteger quotient = BigIntegerMath.divide(p, q, UNNECESSARY);
BigInteger undone = quotient.multiply(q);
if (!p.equals(undone)) {
failFormat("expected %s.multiply(%s) = %s; got %s", quotient, q, p, undone);
}
assertTrue(dividesEvenly);
} catch (ArithmeticException e) {
assertFalse(dividesEvenly);
}
}
}
}
public void testIsPowerOfTwo() {
for (BigInteger x : ALL_BIGINTEGER_CANDIDATES) {
// Checks for a single bit set.
boolean expected = x.signum() > 0 & x.and(x.subtract(ONE)).equals(ZERO);
assertEquals(expected, BigIntegerMath.isPowerOfTwo(x));
}
}
@GwtIncompatible // TODO
public void testLog10TrivialOnPowerOf10() {
BigInteger x = BigInteger.TEN.pow(100);
for (RoundingMode mode : ALL_ROUNDING_MODES) {
assertEquals(100, BigIntegerMath.log10(x, mode));
}
}
@GwtIncompatible // TODO
public void testZeroDivIsAlwaysZero() {
for (BigInteger q : NONZERO_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : ALL_ROUNDING_MODES) {
assertEquals(ZERO, BigIntegerMath.divide(ZERO, q, mode));
}
}
}
public void testLog2Floor() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(FLOOR, DOWN)) {
int result = BigIntegerMath.log2(x, mode);
assertTrue(ZERO.setBit(result).compareTo(x) <= 0);
assertTrue(ZERO.setBit(result + 1).compareTo(x) > 0);
}
}
}
public void testLog2Ceiling() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(CEILING, UP)) {
int result = BigIntegerMath.log2(x, mode);
assertTrue(ZERO.setBit(result).compareTo(x) >= 0);
assertTrue(result == 0 || ZERO.setBit(result - 1).compareTo(x) < 0);
}
}
}
public void testFloorPowerOfTwoNegative() {
for (BigInteger x : NEGATIVE_BIGINTEGER_CANDIDATES) {
try {
BigIntegerMath.floorPowerOfTwo(x);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
public void testLog2NegativeAlwaysThrows() {
for (RoundingMode mode : ALL_ROUNDING_MODES) {
try {
BigIntegerMath.log2(BigInteger.valueOf(-1), mode);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
public void testLog2HalfDown() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int result = BigIntegerMath.log2(x, HALF_DOWN);
BigInteger x2 = x.pow(2);
// x^2 <= 2^(2 * result + 1), or else we would have rounded up
assertTrue(ZERO.setBit(2 * result + 1).compareTo(x2) >= 0);
// x^2 > 2^(2 * result - 1), or else we would have rounded down
assertTrue(result == 0 || ZERO.setBit(2 * result - 1).compareTo(x2) < 0);
}
}
@GwtIncompatible // TODO
public void testLog10ZeroAlwaysThrows() {
for (RoundingMode mode : ALL_ROUNDING_MODES) {
try {
BigIntegerMath.log10(ZERO, mode);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
@GwtIncompatible // TODO
public void testLog10Floor() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(FLOOR, DOWN)) {
int result = BigIntegerMath.log10(x, mode);
assertTrue(TEN.pow(result).compareTo(x) <= 0);
assertTrue(TEN.pow(result + 1).compareTo(x) > 0);
}
}
}
@GwtIncompatible // TODO
public void testSqrtNegativeAlwaysThrows() {
for (RoundingMode mode : ALL_ROUNDING_MODES) {
try {
BigIntegerMath.sqrt(BigInteger.valueOf(-1), mode);
fail("Expected IllegalArgumentException");
} catch (IllegalArgumentException expected) {
}
}
}
@GwtIncompatible // TODO
public void testLog10Ceiling() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(CEILING, UP)) {
int result = BigIntegerMath.log10(x, mode);
assertTrue(TEN.pow(result).compareTo(x) >= 0);
assertTrue(result == 0 || TEN.pow(result - 1).compareTo(x) < 0);
}
}
}
@GwtIncompatible // TODO
public void testSqrtCeiling() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(CEILING, UP)) {
BigInteger result = BigIntegerMath.sqrt(x, mode);
assertTrue(result.compareTo(ZERO) > 0);
assertTrue(result.pow(2).compareTo(x) >= 0);
assertTrue(result.signum() == 0 || result.subtract(ONE).pow(2).compareTo(x) < 0);
}
}
}
@GwtIncompatible // TODO
public void testSqrtFloor() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
for (RoundingMode mode : asList(FLOOR, DOWN)) {
BigInteger result = BigIntegerMath.sqrt(x, mode);
assertTrue(result.compareTo(ZERO) > 0);
assertTrue(result.pow(2).compareTo(x) <= 0);
assertTrue(result.add(ONE).pow(2).compareTo(x) > 0);
}
}
}
@GwtIncompatible // TODO
public void testLog10HalfDown() {
for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
int result = BigIntegerMath.log10(x, HALF_DOWN);
BigInteger x2 = x.pow(2);
// x^2 <= 10^(2 * result + 1), or else we would have rounded up
assertTrue(TEN.pow(2 * result + 1).compareTo(x2) >= 0);
// x^2 > 10^(2 * result - 1), or else we would have rounded down
assertTrue(result == 0 || TEN.pow(2 * result - 1).compareTo(x2) < 0);
}
}
