@GwtCompatible(emulated=true) public final class BigIntegerMath extends Object
BigInteger.
The implementations of many methods in this class are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).
Similar functionality for int and for long can be found in IntMath and
LongMath respectively.
| Modifier and Type | Method and Description |
|---|---|
static BigInteger |
binomial(int n,
int k)
Returns
n choose k, also known as the binomial coefficient of n and
k, that is, n! / (k! (n - k)!). |
static BigInteger |
ceilingPowerOfTwo(BigInteger x)
Returns the smallest power of two greater than or equal to
x. |
static BigInteger |
divide(BigInteger p,
BigInteger q,
RoundingMode mode)
Returns the result of dividing
p by q, rounding using the specified
RoundingMode. |
static BigInteger |
factorial(int n)
Returns
n!, that is, the product of the first n positive integers, or 1
if n == 0. |
static BigInteger |
floorPowerOfTwo(BigInteger x)
Returns the largest power of two less than or equal to
x. |
static boolean |
isPowerOfTwo(BigInteger x)
Returns
true if x represents a power of two. |
static int |
log10(BigInteger x,
RoundingMode mode)
Returns the base-10 logarithm of
x, rounded according to the specified rounding mode. |
static int |
log2(BigInteger x,
RoundingMode mode)
Returns the base-2 logarithm of
x, rounded according to the specified rounding mode. |
static BigInteger |
sqrt(BigInteger x,
RoundingMode mode)
Returns the square root of
x, rounded with the specified rounding mode. |
@Beta public static BigInteger ceilingPowerOfTwo(BigInteger x)
x. This is equivalent to
BigInteger.valueOf(2).pow(log2(x, CEILING)).IllegalArgumentException - if x <= 0@Beta public static BigInteger floorPowerOfTwo(BigInteger x)
x. This is equivalent to
BigInteger.valueOf(2).pow(log2(x, FLOOR)).IllegalArgumentException - if x <= 0public static boolean isPowerOfTwo(BigInteger x)
true if x represents a power of two.public static int log2(BigInteger x, RoundingMode mode)
x, rounded according to the specified rounding mode.IllegalArgumentException - if x <= 0ArithmeticException - if mode is RoundingMode.UNNECESSARY and x
is not a power of two@GwtIncompatible public static int log10(BigInteger x, RoundingMode mode)
x, rounded according to the specified rounding mode.IllegalArgumentException - if x <= 0ArithmeticException - if mode is RoundingMode.UNNECESSARY and x
is not a power of ten@GwtIncompatible public static BigInteger sqrt(BigInteger x, RoundingMode mode)
x, rounded with the specified rounding mode.IllegalArgumentException - if x < 0ArithmeticException - if mode is RoundingMode.UNNECESSARY and
sqrt(x) is not an integer@GwtIncompatible public static BigInteger divide(BigInteger p, BigInteger q, RoundingMode mode)
p by q, rounding using the specified
RoundingMode.ArithmeticException - if q == 0, or if mode == UNNECESSARY and a
is not an integer multiple of bpublic static BigInteger factorial(int n)
n!, that is, the product of the first n positive integers, or 1
if n == 0.
Warning: the result takes O(n log n) space, so use cautiously.
This uses an efficient binary recursive algorithm to compute the factorial with balanced multiplies. It also removes all the 2s from the intermediate products (shifting them back in at the end).
IllegalArgumentException - if n < 0public static BigInteger binomial(int n, int k)
n choose k, also known as the binomial coefficient of n and
k, that is, n! / (k! (n - k)!).
Warning: the result can take as much as O(k log n) space.
IllegalArgumentException - if n < 0, k < 0, or k > nCopyright © 2010-2016. All Rights Reserved.