Math

public final class Math
extends Object

java.lang.Object
   ↳ java.lang.Math


The class Math contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions.

Unlike some of the numeric methods of class StrictMath, all implementations of the equivalent functions of class Math are not defined to return the bit-for-bit same results. This relaxation permits better-performing implementations where strict reproducibility is not required.

By default many of the Math methods simply call the equivalent method in StrictMath for their implementation. Code generators are encouraged to use platform-specific native libraries or microprocessor instructions, where available, to provide higher-performance implementations of Math methods. Such higher-performance implementations still must conform to the specification for Math.

The quality of implementation specifications concern two properties, accuracy of the returned result and monotonicity of the method. Accuracy of the floating-point Math methods is measured in terms of ulps, units in the last place. For a given floating-point format, an ulp of a specific real number value is the distance between the two floating-point values bracketing that numerical value. When discussing the accuracy of a method as a whole rather than at a specific argument, the number of ulps cited is for the worst-case error at any argument. If a method always has an error less than 0.5 ulps, the method always returns the floating-point number nearest the exact result; such a method is correctly rounded. A correctly rounded method is generally the best a floating-point approximation can be; however, it is impractical for many floating-point methods to be correctly rounded. Instead, for the Math class, a larger error bound of 1 or 2 ulps is allowed for certain methods. Informally, with a 1 ulp error bound, when the exact result is a representable number, the exact result should be returned as the computed result; otherwise, either of the two floating-point values which bracket the exact result may be returned. For exact results large in magnitude, one of the endpoints of the bracket may be infinite. Besides accuracy at individual arguments, maintaining proper relations between the method at different arguments is also important. Therefore, most methods with more than 0.5 ulp errors are required to be semi-monotonic: whenever the mathematical function is non-decreasing, so is the floating-point approximation, likewise, whenever the mathematical function is non-increasing, so is the floating-point approximation. Not all approximations that have 1 ulp accuracy will automatically meet the monotonicity requirements.

The platform uses signed two's complement integer arithmetic with int and long primitive types. The developer should choose the primitive type to ensure that arithmetic operations consistently produce correct results, which in some cases means the operations will not overflow the range of values of the computation. The best practice is to choose the primitive type and algorithm to avoid overflow. In cases where the size is int or long and overflow errors need to be detected, the methods addExact, subtractExact, multiplyExact, toIntExact, incrementExact, decrementExact and negateExact throw an ArithmeticException when the results overflow. For the arithmetic operations divide and absolute value, overflow occurs only with a specific minimum or maximum value and should be checked against the minimum or maximum as appropriate.

The 2019 revision of the IEEE 754 floating-point standard includes a section of recommended operations and the semantics of those operations if they are included in a programming environment. The recommended operations present in this class include sin, cos, tan, asin, acos, atan, exp, expm1, log, log10, log1p, sinh, cosh, tanh, hypot, and pow. (The sqrt operation is a required part of IEEE 754 from a different section of the standard.) The special case behavior of the recommended operations generally follows the guidance of the IEEE 754 standard. However, the pow method defines different behavior for some arguments, as noted in its specification. The IEEE 754 standard defines its operations to be correctly rounded, which is a more stringent quality of implementation condition than required for most of the methods in question that are also included in this class.

Summary

Constants

double E

The double value that is closer than any other to e, the base of the natural logarithms.

double PI

The double value that is closer than any other to pi, the ratio of the circumference of a circle to its diameter.

Public methods

static double IEEEremainder(double f1, double f2)

Computes the remainder operation on two arguments as prescribed by the IEEE 754 standard.

static long abs(long a)

Returns the absolute value of a long value.

static int abs(int a)

Returns the absolute value of an int value.

static float abs(float a)

Returns the absolute value of a float value.

static double abs(double a)

Returns the absolute value of a double value.

static long absExact(long a)

Returns the mathematical absolute value of an long value if it is exactly representable as an long, throwing ArithmeticException if the result overflows the positive long range.

static int absExact(int a)

Returns the mathematical absolute value of an int value if it is exactly representable as an int, throwing ArithmeticException if the result overflows the positive int range.

static double acos(double a)

Returns the arc cosine of a value; the returned angle is in the range 0.0 through pi.

static int addExact(int x, int y)

Returns the sum of its arguments, throwing an exception if the result overflows an int.

static long addExact(long x, long y)

Returns the sum of its arguments, throwing an exception if the result overflows a long.

static double asin(double a)

Returns the arc sine of a value; the returned angle is in the range -pi/2 through pi/2.

static double atan(double a)

Returns the arc tangent of a value; the returned angle is in the range -pi/2 through pi/2.

static double atan2(double y, double x)

Returns the angle theta from the conversion of rectangular coordinates (xy) to polar coordinates (r, theta).

static double cbrt(double a)

Returns the cube root of a double value.

static double ceil(double a)

Returns the smallest (closest to negative infinity) double value that is greater than or equal to the argument and is equal to a mathematical integer.

static float copySign(float magnitude, float sign)

Returns the first floating-point argument with the sign of the second floating-point argument.

static double copySign(double magnitude, double sign)

Returns the first floating-point argument with the sign of the second floating-point argument.

static double cos(double a)

Returns the trigonometric cosine of an angle.

static double cosh(double x)

Returns the hyperbolic cosine of a double value.

static long decrementExact(long a)

Returns the argument decremented by one, throwing an exception if the result overflows a long.

static int decrementExact(int a)

Returns the argument decremented by one, throwing an exception if the result overflows an int.

static double exp(double a)

Returns Euler's number e raised to the power of a double value.

static double expm1(double x)

Returns ex -1.

static double floor(double a)

Returns the largest (closest to positive infinity) double value that is less than or equal to the argument and is equal to a mathematical integer.

static int floorDiv(int x, int y)

Returns the largest (closest to positive infinity) int value that is less than or equal to the algebraic quotient.

static long floorDiv(long x, long y)

Returns the largest (closest to positive infinity) long value that is less than or equal to the algebraic quotient.

static long floorDiv(long x, int y)

Returns the largest (closest to positive infinity) long value that is less than or equal to the algebraic quotient.

static long floorMod(long x, long y)

Returns the floor modulus of the long arguments.

static int floorMod(int x, int y)

Returns the floor modulus of the int arguments.

static int floorMod(long x, int y)

Returns the floor modulus of the long and int arguments.

static double fma(double a, double b, double c)

Returns the fused multiply add of the three arguments; that is, returns the exact product of the first two arguments summed with the third argument and then rounded once to the nearest double.

static float fma(float a, float b, float c)

Returns the fused multiply add of the three arguments; that is, returns the exact product of the first two arguments summed with the third argument and then rounded once to the nearest float.

static int getExponent(double d)

Returns the unbiased exponent used in the representation of a double.

static int getExponent(float f)

Returns the unbiased exponent used in the representation of a float.

static double hypot(double x, double y)

Returns sqrt(x2 +y2) without intermediate overflow or underflow.

static int incrementExact(int a)

Returns the argument incremented by one, throwing an exception if the result overflows an int.

static long incrementExact(long a)

Returns the argument incremented by one, throwing an exception if the result overflows a long.

static double log(double a)

Returns the natural logarithm (base e) of a double value.

static double log10(double a)

Returns the base 10 logarithm of a double value.

static double log1p(double x)

Returns the natural logarithm of the sum of the argument and 1.

static int max(int a, int b)

Returns the greater of two int values.

static long max(long a, long b)

Returns the greater of two long values.

static float max(float a, float b)

Returns the greater of two float values.

static double max(double a, double b)

Returns the greater of two double values.

static float min(float a, float b)

Returns the smaller of two float values.

static double min(double a, double b)

Returns the smaller of two double values.

static int min(int a, int b)

Returns the smaller of two int values.

static long min(long a, long b)

Returns the smaller of two long values.

static int multiplyExact(int x, int y)

Returns the product of the arguments, throwing an exception if the result overflows an int.

static long multiplyExact(long x, long y)

Returns the product of the arguments, throwing an exception if the result overflows a long.

static long multiplyExact(long x, int y)

Returns the product of the arguments, throwing an exception if the result overflows a long.

static long multiplyFull(int x, int y)

Returns the exact mathematical product of the arguments.

static long multiplyHigh(long x, long y)

Returns as a long the most significant 64 bits of the 128-bit product of two 64-bit factors.

static int negateExact(int a)

Returns the negation of the argument, throwing an exception if the result overflows an int.

static long negateExact(long a)

Returns the negation of the argument, throwing an exception if the result overflows a long.

static double nextAfter(double start, double direction)

Returns the floating-point number adjacent to the first argument in the direction of the second argument.

static float nextAfter(float start, double direction)

Returns the floating-point number adjacent to the first argument in the direction of the second argument.

static double nextDown(double d)

Returns the floating-point value adjacent to d in the direction of negative infinity.

static float nextDown(float f)

Returns the floating-point value adjacent to f in the direction of negative infinity.

static float nextUp(float f)

Returns the floating-point value adjacent to f in the direction of positive infinity.

static double nextUp(double d)

Returns the floating-point value adjacent to d in the direction of positive infinity.

static double pow(double a, double b)

Returns the value of the first argument raised to the power of the second argument.

static double random()

Returns a double value with a positive sign, greater than or equal to 0.0 and less than 1.0.

static double rint(double a)

Returns the double value that is closest in value to the argument and is equal to a mathematical integer.

static long round(double a)

Returns the closest long to the argument, with ties rounding to positive infinity.

static int round(float a)

Returns the closest int to the argument, with ties rounding to positive infinity.

static float scalb(float f, int scaleFactor)

Returns f × 2scaleFactor rounded as if performed by a single correctly rounded floating-point multiply.

static double scalb(double d, int scaleFactor)

Returns d × 2scaleFactor rounded as if performed by a single correctly rounded floating-point multiply.

static double signum(double d)

Returns the signum function of the argument; zero if the argument is zero, 1.0 if the argument is greater than zero, -1.0 if the argument is less than zero.

static float signum(float f)

Returns the signum function of the argument; zero if the argument is zero, 1.0f if the argument is greater than zero, -1.0f if the argument is less than zero.

static double sin(double a)

Returns the trigonometric sine of an angle.

static double sinh(double x)

Returns the hyperbolic sine of a double value.

static double sqrt(double a)

Returns the correctly rounded positive square root of a double value.

static long subtractExact(long x, long y)

Returns the difference of the arguments, throwing an exception if the result overflows a long.

static int subtractExact(int x, int y)

Returns the difference of the arguments, throwing an exception if the result overflows an int.

static double tan(double a)

Returns the trigonometric tangent of an angle.

static double tanh(double x)

Returns the hyperbolic tangent of a double value.

static double toDegrees(double angrad)

Converts an angle measured in radians to an approximately equivalent angle measured in degrees.

static int toIntExact(long value)

Returns the value of the long argument, throwing an exception if the value overflows an int.

static double toRadians(double angdeg)

Converts an angle measured in degrees to an approximately equivalent angle measured in radians.

static double ulp(double d)

Returns the size of an ulp of the argument.

static float ulp(float f)

Returns the size of an ulp of the argument.

Inherited methods

Constants

E

Added in API level 1
public static final double E

The double value that is closer than any other to e, the base of the natural logarithms.

Constant Value: 2.718281828459045

PI

Added in API level 1
public static final double PI

The double value that is closer than any other to pi, the ratio of the circumference of a circle to its diameter.

Constant Value: 3.141592653589793

Public methods

IEEEremainder

Added in API level 1
public static double IEEEremainder (double f1, 
                double f2)

Computes the remainder operation on two arguments as prescribed by the IEEE 754 standard. The remainder value is mathematically equal to f1 - f2 × n, where n is the mathematical integer closest to the exact mathematical value of the quotient f1/f2, and if two mathematical integers are equally close to f1/f2, then n is the integer that is even. If the remainder is zero, its sign is the same as the sign of the first argument. Special cases:

  • If either argument is NaN, or the first argument is infinite, or the second argument is positive zero or negative zero, then the result is NaN.
  • If the first argument is finite and the second argument is infinite, then the result is the same as the first argument.

Parameters
f1 double: the dividend.

f2 double: the divisor.

Returns
double the remainder when f1 is divided by f2.

abs

Added in API level 1
public static long abs (long a)

Returns the absolute value of a long value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned.

Note that if the argument is equal to the value of Long.MIN_VALUE, the most negative representable long value, the result is that same value, which is negative. In contrast, the Math#absExact(long) method throws an ArithmeticException for this value.

Parameters
a long: the argument whose absolute value is to be determined

Returns
long the absolute value of the argument.

See also:

abs

Added in API level 1
public static int abs (int a)

Returns the absolute value of an int value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned.

Note that if the argument is equal to the value of Integer.MIN_VALUE, the most negative representable int value, the result is that same value, which is negative. In contrast, the Math#absExact(int) method throws an ArithmeticException for this value.

Parameters
a int: the argument whose absolute value is to be determined

Returns
int the absolute value of the argument.

See also:

abs

Added in API level 1
public static float abs (float a)

Returns the absolute value of a float value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned. Special cases:

  • If the argument is positive zero or negative zero, the result is positive zero.
  • If the argument is infinite, the result is positive infinity.
  • If the argument is NaN, the result is NaN.

API Note:
  • As implied by the above, one valid implementation of this method is given by the expression below which computes a float with the same exponent and significand as the argument but with a guaranteed zero sign bit indicating a positive value:
    Float.intBitsToFloat(0x7fffffff & Float.floatToRawIntBits(a))
Parameters
a float: the argument whose absolute value is to be determined

Returns
float the absolute value of the argument.

abs

Added in API level 1
public static double abs (double a)

Returns the absolute value of a double value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned. Special cases:

  • If the argument is positive zero or negative zero, the result is positive zero.
  • If the argument is infinite, the result is positive infinity.
  • If the argument is NaN, the result is NaN.

API Note:
  • As implied by the above, one valid implementation of this method is given by the expression below which computes a double with the same exponent and significand as the argument but with a guaranteed zero sign bit indicating a positive value:
    Double.longBitsToDouble((Double.doubleToRawLongBits(a)<<1)>>>1)
Parameters
a double: the argument whose absolute value is to be determined

Returns
double the absolute value of the argument.

absExact

Added in API level 34
public static long absExact (long a)

Returns the mathematical absolute value of an long value if it is exactly representable as an long, throwing ArithmeticException if the result overflows the positive long range.

Since the range of two's complement integers is asymmetric with one additional negative value (JLS {@jls 4.2.1}), the mathematical absolute value of Long#MIN_VALUE overflows the positive long range, so an exception is thrown for that argument.

Parameters
a long: the argument whose absolute value is to be determined

Returns
long the absolute value of the argument, unless overflow occurs

Throws
ArithmeticException if the argument is Long#MIN_VALUE

See also:

absExact

Added in API level 34
public static int absExact (int a)

Returns the mathematical absolute value of an int value if it is exactly representable as an int, throwing ArithmeticException if the result overflows the positive int range.

Since the range of two's complement integers is asymmetric with one additional negative value (JLS {@jls 4.2.1}), the mathematical absolute value of Integer#MIN_VALUE overflows the positive int range, so an exception is thrown for that argument.

Parameters
a int: the argument whose absolute value is to be determined

Returns
int the absolute value of the argument, unless overflow occurs

Throws
ArithmeticException if the argument is Integer#MIN_VALUE

See also:

acos

Added in API level 1
public static double acos (double a)

Returns the arc cosine of a value; the returned angle is in the range 0.0 through pi. Special case:

  • If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
  • If the argument is 1.0, the result is positive zero.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: the value whose arc cosine is to be returned.

Returns
double the arc cosine of the argument.

addExact

Added in API level 24
public static int addExact (int x, 
                int y)

Returns the sum of its arguments, throwing an exception if the result overflows an int.

Parameters
x int: the first value

y int: the second value

Returns
int the result

Throws
ArithmeticException if the result overflows an int

addExact

Added in API level 24
public static long addExact (long x, 
                long y)

Returns the sum of its arguments, throwing an exception if the result overflows a long.

Parameters
x long: the first value

y long: the second value

Returns
long the result

Throws
ArithmeticException if the result overflows a long

asin

Added in API level 1
public static double asin (double a)

Returns the arc sine of a value; the returned angle is in the range -pi/2 through pi/2. Special cases:

  • If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: the value whose arc sine is to be returned.

Returns
double the arc sine of the argument.

atan

Added in API level 1
public static double atan (double a)

Returns the arc tangent of a value; the returned angle is in the range -pi/2 through pi/2. Special cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.
  • If the argument is infinite, then the result is the closest value to pi/2 with the same sign as the input.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: the value whose arc tangent is to be returned.

Returns
double the arc tangent of the argument.

atan2

Added in API level 1
public static double atan2 (double y, 
                double x)

Returns the angle theta from the conversion of rectangular coordinates (xy) to polar coordinates (r, theta). This method computes the phase theta by computing an arc tangent of y/x in the range of -pi to pi. Special cases:

  • If either argument is NaN, then the result is NaN.
  • If the first argument is positive zero and the second argument is positive, or the first argument is positive and finite and the second argument is positive infinity, then the result is positive zero.
  • If the first argument is negative zero and the second argument is positive, or the first argument is negative and finite and the second argument is positive infinity, then the result is negative zero.
  • If the first argument is positive zero and the second argument is negative, or the first argument is positive and finite and the second argument is negative infinity, then the result is the double value closest to pi.
  • If the first argument is negative zero and the second argument is negative, or the first argument is negative and finite and the second argument is negative infinity, then the result is the double value closest to -pi.
  • If the first argument is positive and the second argument is positive zero or negative zero, or the first argument is positive infinity and the second argument is finite, then the result is the double value closest to pi/2.
  • If the first argument is negative and the second argument is positive zero or negative zero, or the first argument is negative infinity and the second argument is finite, then the result is the double value closest to -pi/2.
  • If both arguments are positive infinity, then the result is the double value closest to pi/4.
  • If the first argument is positive infinity and the second argument is negative infinity, then the result is the double value closest to 3*pi/4.
  • If the first argument is negative infinity and the second argument is positive infinity, then the result is the double value closest to -pi/4.
  • If both arguments are negative infinity, then the result is the double value closest to -3*pi/4.

The computed result must be within 2 ulps of the exact result. Results must be semi-monotonic.

API Note:
  • For y with a positive sign and finite nonzero x, the exact mathematical value of atan2 is equal to:
    • If x > 0, atan(abs(y/x))
    • If x < 0, π - atan(abs(y/x))
Parameters
y double: the ordinate coordinate

x double: the abscissa coordinate

Returns
double the theta component of the point (rtheta) in polar coordinates that corresponds to the point (xy) in Cartesian coordinates.

cbrt

Added in API level 1
public static double cbrt (double a)

Returns the cube root of a double value. For positive finite x, cbrt(-x) == -cbrt(x); that is, the cube root of a negative value is the negative of the cube root of that value's magnitude. Special cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is infinite, then the result is an infinity with the same sign as the argument.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result.

Parameters
a double: a value.

Returns
double the cube root of a.

ceil

Added in API level 1
public static double ceil (double a)

Returns the smallest (closest to negative infinity) double value that is greater than or equal to the argument and is equal to a mathematical integer. Special cases:

  • If the argument value is already equal to a mathematical integer, then the result is the same as the argument.
  • If the argument is NaN or an infinity or positive zero or negative zero, then the result is the same as the argument.
  • If the argument value is less than zero but greater than -1.0, then the result is negative zero.
Note that the value of Math.ceil(x) is exactly the value of -Math.floor(-x).

Parameters
a double: a value.

Returns
double the smallest (closest to negative infinity) floating-point value that is greater than or equal to the argument and is equal to a mathematical integer.

copySign

Added in API level 9
public static float copySign (float magnitude, 
                float sign)

Returns the first floating-point argument with the sign of the second floating-point argument. Note that unlike the StrictMath.copySign method, this method does not require NaN sign arguments to be treated as positive values; implementations are permitted to treat some NaN arguments as positive and other NaN arguments as negative to allow greater performance.

Parameters
magnitude float: the parameter providing the magnitude of the result

sign float: the parameter providing the sign of the result

Returns
float a value with the magnitude of magnitude and the sign of sign.

copySign

Added in API level 9
public static double copySign (double magnitude, 
                double sign)

Returns the first floating-point argument with the sign of the second floating-point argument. Note that unlike the StrictMath.copySign method, this method does not require NaN sign arguments to be treated as positive values; implementations are permitted to treat some NaN arguments as positive and other NaN arguments as negative to allow greater performance.

Parameters
magnitude double: the parameter providing the magnitude of the result

sign double: the parameter providing the sign of the result

Returns
double a value with the magnitude of magnitude and the sign of sign.

cos

Added in API level 1
public static double cos (double a)

Returns the trigonometric cosine of an angle. Special cases:

  • If the argument is NaN or an infinity, then the result is NaN.
  • If the argument is zero, then the result is 1.0.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: an angle, in radians.

Returns
double the cosine of the argument.

cosh

Added in API level 1
public static double cosh (double x)

Returns the hyperbolic cosine of a double value. The hyperbolic cosine of x is defined to be (ex + e-x)/2 where e is Euler's number.

Special cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is infinite, then the result is positive infinity.
  • If the argument is zero, then the result is 1.0.

The computed result must be within 2.5 ulps of the exact result.

Parameters
x double: The number whose hyperbolic cosine is to be returned.

Returns
double The hyperbolic cosine of x.

decrementExact

Added in API level 24
public static long decrementExact (long a)

Returns the argument decremented by one, throwing an exception if the result overflows a long. The overflow only occurs for the minimum value.

Parameters
a long: the value to decrement

Returns
long the result

Throws
ArithmeticException if the result overflows a long

decrementExact

Added in API level 24
public static int decrementExact (int a)

Returns the argument decremented by one, throwing an exception if the result overflows an int. The overflow only occurs for the minimum value.

Parameters
a int: the value to decrement

Returns
int the result

Throws
ArithmeticException if the result overflows an int

exp

Added in API level 1
public static double exp (double a)

Returns Euler's number e raised to the power of a double value. Special cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is negative infinity, then the result is positive zero.
  • If the argument is zero, then the result is 1.0.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: the exponent to raise e to.

Returns
double the value ea, where e is the base of the natural logarithms.

expm1

Added in API level 1
public static double expm1 (double x)

Returns ex -1. Note that for values of x near 0, the exact sum of expm1(x) + 1 is much closer to the true result of ex than exp(x).

Special cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is negative infinity, then the result is -1.0.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic. The result of expm1 for any finite input must be greater than or equal to -1.0. Note that once the exact result of ex - 1 is within 1/2 ulp of the limit value -1, -1.0 should be returned.

Parameters
x double: the exponent to raise e to in the computation of ex -1.

Returns
double the value ex - 1.

floor

Added in API level 1
public static double floor (double a)

Returns the largest (closest to positive infinity) double value that is less than or equal to the argument and is equal to a mathematical integer. Special cases:

  • If the argument value is already equal to a mathematical integer, then the result is the same as the argument.
  • If the argument is NaN or an infinity or positive zero or negative zero, then the result is the same as the argument.

Parameters
a double: a value.

Returns
double the largest (closest to positive infinity) floating-point value that less than or equal to the argument and is equal to a mathematical integer.

floorDiv

Added in API level 24
public static int floorDiv (int x, 
                int y)

Returns the largest (closest to positive infinity) int value that is less than or equal to the algebraic quotient. There is one special case, if the dividend is the Integer.MIN_VALUE and the divisor is -1, then integer overflow occurs and the result is equal to Integer.MIN_VALUE.

Normal integer division operates under the round to zero rounding mode (truncation). This operation instead acts under the round toward negative infinity (floor) rounding mode. The floor rounding mode gives different results from truncation when the exact result is negative.

  • If the signs of the arguments are the same, the results of floorDiv and the / operator are the same.
    For example, floorDiv(4, 3) == 1 and (4 / 3) == 1.
  • If the signs of the arguments are different, the quotient is negative and floorDiv returns the integer less than or equal to the quotient and the / operator returns the integer closest to zero.
    For example, floorDiv(-4, 3) == -2, whereas (-4 / 3) == -1.

Parameters
x int: the dividend

y int: the divisor

Returns
int the largest (closest to positive infinity) int value that is less than or equal to the algebraic quotient.

Throws
ArithmeticException if the divisor y is zero

floorDiv

Added in API level 24
public static long floorDiv (long x, 
                long y)

Returns the largest (closest to positive infinity) long value that is less than or equal to the algebraic quotient. There is one special case, if the dividend is the Long.MIN_VALUE and the divisor is -1, then integer overflow occurs and the result is equal to Long.MIN_VALUE.

Normal integer division operates under the round to zero rounding mode (truncation). This operation instead acts under the round toward negative infinity (floor) rounding mode. The floor rounding mode gives different results from truncation when the exact result is negative.

For examples, see floorDiv(int, int).

Parameters
x long: the dividend

y long: the divisor

Returns
long the largest (closest to positive infinity) long value that is less than or equal to the algebraic quotient.

Throws
ArithmeticException if the divisor y is zero

floorDiv

Added in API level 31
public static long floorDiv (long x, 
                int y)

Returns the largest (closest to positive infinity) long value that is less than or equal to the algebraic quotient. There is one special case, if the dividend is the Long.MIN_VALUE and the divisor is -1, then integer overflow occurs and the result is equal to Long.MIN_VALUE.

Normal integer division operates under the round to zero rounding mode (truncation). This operation instead acts under the round toward negative infinity (floor) rounding mode. The floor rounding mode gives different results from truncation when the exact result is negative.

For examples, see floorDiv(int, int).

Parameters
x long: the dividend

y int: the divisor

Returns
long the largest (closest to positive infinity) int value that is less than or equal to the algebraic quotient.

Throws
ArithmeticException if the divisor y is zero

floorMod

Added in API level 24
public static long floorMod (long x, 
                long y)

Returns the floor modulus of the long arguments.

The floor modulus is x - (floorDiv(x, y) * y), has the same sign as the divisor y, and is in the range of -abs(y) < r < +abs(y).

The relationship between floorDiv and floorMod is such that:

  • floorDiv(x, y) * y + floorMod(x, y) == x

For examples, see floorMod(int, int).

Parameters
x long: the dividend

y long: the divisor

Returns
long the floor modulus x - (floorDiv(x, y) * y)

Throws
ArithmeticException if the divisor y is zero

floorMod

Added in API level 24
public static int floorMod (int x, 
                int y)

Returns the floor modulus of the int arguments.

The floor modulus is x - (floorDiv(x, y) * y), has the same sign as the divisor y, and is in the range of -abs(y) < r < +abs(y).

The relationship between floorDiv and floorMod is such that:

  • floorDiv(x, y) * y + floorMod(x, y) == x

The difference in values between floorMod and the % operator is due to the difference between floorDiv that returns the integer less than or equal to the quotient and the / operator that returns the integer closest to zero.

Examples:

  • If the signs of the arguments are the same, the results of floorMod and the % operator are the same.
    • floorMod(+4, +3) == +1;   and (+4 % +3) == +1
    • floorMod(-4, -3) == -1;   and (-4 % -3) == -1
  • If the signs of the arguments are different, the results differ from the % operator.
    • floorMod(+4, -3) == -2;   and (+4 % -3) == +1
    • floorMod(-4, +3) == +2;   and (-4 % +3) == -1

If the signs of arguments are unknown and a positive modulus is needed it can be computed as (floorMod(x, y) + abs(y)) % abs(y).

Parameters
x int: the dividend

y int: the divisor

Returns
int the floor modulus x - (floorDiv(x, y) * y)

Throws
ArithmeticException if the divisor y is zero

See also:

floorMod

Added in API level 31
public static int floorMod (long x, 
                int y)

Returns the floor modulus of the long and int arguments.

The floor modulus is x - (floorDiv(x, y) * y), has the same sign as the divisor y, and is in the range of -abs(y) < r < +abs(y).

The relationship between floorDiv and floorMod is such that:

  • floorDiv(x, y) * y + floorMod(x, y) == x

For examples, see floorMod(int, int).

Parameters
x long: the dividend

y int: the divisor

Returns
int the floor modulus x - (floorDiv(x, y) * y)

Throws
ArithmeticException if the divisor y is zero

fma

Added in API level 33
public static double fma (double a, 
                double b, 
                double c)

Returns the fused multiply add of the three arguments; that is, returns the exact product of the first two arguments summed with the third argument and then rounded once to the nearest double. The rounding is done using the round to nearest even rounding mode. In contrast, if a * b + c is evaluated as a regular floating-point expression, two rounding errors are involved, the first for the multiply operation, the second for the addition operation.

Special cases:

  • If any argument is NaN, the result is NaN.
  • If one of the first two arguments is infinite and the other is zero, the result is NaN.
  • If the exact product of the first two arguments is infinite (in other words, at least one of the arguments is infinite and the other is neither zero nor NaN) and the third argument is an infinity of the opposite sign, the result is NaN.

Note that fma(a, 1.0, c) returns the same result as (a + c). However, fma(a, b, +0.0) does not always return the same result as (a * b) since fma(-0.0, +0.0, +0.0) is +0.0 while (-0.0 * +0.0) is -0.0; fma(a, b, -0.0) is equivalent to (a * b) however.

API Note:
  • This method corresponds to the fusedMultiplyAdd operation defined in IEEE 754-2008.
Parameters
a double: a value

b double: a value

c double: a value

Returns
double (a × b + c) computed, as if with unlimited range and precision, and rounded once to the nearest double value

fma

Added in API level 33
public static float fma (float a, 
                float b, 
                float c)

Returns the fused multiply add of the three arguments; that is, returns the exact product of the first two arguments summed with the third argument and then rounded once to the nearest float. The rounding is done using the round to nearest even rounding mode. In contrast, if a * b + c is evaluated as a regular floating-point expression, two rounding errors are involved, the first for the multiply operation, the second for the addition operation.

Special cases:

  • If any argument is NaN, the result is NaN.
  • If one of the first two arguments is infinite and the other is zero, the result is NaN.
  • If the exact product of the first two arguments is infinite (in other words, at least one of the arguments is infinite and the other is neither zero nor NaN) and the third argument is an infinity of the opposite sign, the result is NaN.

Note that fma(a, 1.0f, c) returns the same result as (a + c). However, fma(a, b, +0.0f) does not always return the same result as (a * b) since fma(-0.0f, +0.0f, +0.0f) is +0.0f while (-0.0f * +0.0f) is -0.0f; fma(a, b, -0.0f) is equivalent to (a * b) however.

API Note:
  • This method corresponds to the fusedMultiplyAdd operation defined in IEEE 754-2008.
Parameters
a float: a value

b float: a value

c float: a value

Returns
float (a × b + c) computed, as if with unlimited range and precision, and rounded once to the nearest float value

getExponent

Added in API level 9
public static int getExponent (double d)

Returns the unbiased exponent used in the representation of a double. Special cases:

Parameters
d double: a double value

Returns
int the unbiased exponent of the argument

getExponent

Added in API level 9
public static int getExponent (float f)

Returns the unbiased exponent used in the representation of a float. Special cases:

Parameters
f float: a float value

Returns
int the unbiased exponent of the argument

hypot

Added in API level 1
public static double hypot (double x, 
                double y)

Returns sqrt(x2 +y2) without intermediate overflow or underflow.

Special cases:

  • If either argument is infinite, then the result is positive infinity.
  • If either argument is NaN and neither argument is infinite, then the result is NaN.
  • If both arguments are zero, the result is positive zero.

The computed result must be within 1 ulp of the exact result. If one parameter is held constant, the results must be semi-monotonic in the other parameter.

Parameters
x double: a value

y double: a value

Returns
double sqrt(x2 +y2) without intermediate overflow or underflow

incrementExact

Added in API level 24
public static int incrementExact (int a)

Returns the argument incremented by one, throwing an exception if the result overflows an int. The overflow only occurs for the maximum value.

Parameters
a int: the value to increment

Returns
int the result

Throws
ArithmeticException if the result overflows an int

incrementExact

Added in API level 24
public static long incrementExact (long a)

Returns the argument incremented by one, throwing an exception if the result overflows a long. The overflow only occurs for the maximum value.

Parameters
a long: the value to increment

Returns
long the result

Throws
ArithmeticException if the result overflows a long

log

Added in API level 1
public static double log (double a)

Returns the natural logarithm (base e) of a double value. Special cases:

  • If the argument is NaN or less than zero, then the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is positive zero or negative zero, then the result is negative infinity.
  • If the argument is 1.0, then the result is positive zero.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: a value

Returns
double the value ln a, the natural logarithm of a.

log10

Added in API level 1
public static double log10 (double a)

Returns the base 10 logarithm of a double value. Special cases:

  • If the argument is NaN or less than zero, then the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is positive zero or negative zero, then the result is negative infinity.
  • If the argument is equal to 10n for integer n, then the result is n. In particular, if the argument is 1.0 (100), then the result is positive zero.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: a value

Returns
double the base 10 logarithm of a.

log1p

Added in API level 1
public static double log1p (double x)

Returns the natural logarithm of the sum of the argument and 1. Note that for small values x, the result of log1p(x) is much closer to the true result of ln(1 + x) than the floating-point evaluation of log(1.0+x).

Special cases:

  • If the argument is NaN or less than -1, then the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is negative one, then the result is negative infinity.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
x double: a value

Returns
double the value ln(x + 1), the natural log of x + 1

max

Added in API level 1
public static int max (int a, 
                int b)

Returns the greater of two int values. That is, the result is the argument closer to the value of Integer#MAX_VALUE. If the arguments have the same value, the result is that same value.

Parameters
a int: an argument.

b int: another argument.

Returns
int the larger of a and b.

max

Added in API level 1
public static long max (long a, 
                long b)

Returns the greater of two long values. That is, the result is the argument closer to the value of Long#MAX_VALUE. If the arguments have the same value, the result is that same value.

Parameters
a long: an argument.

b long: another argument.

Returns
long the larger of a and b.

max

Added in API level 1
public static float max (float a, 
                float b)

Returns the greater of two float values. That is, the result is the argument closer to positive infinity. If the arguments have the same value, the result is that same value. If either value is NaN, then the result is NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. If one argument is positive zero and the other negative zero, the result is positive zero.

Parameters
a float: an argument.

b float: another argument.

Returns
float the larger of a and b.

max

Added in API level 1
public static double max (double a, 
                double b)

Returns the greater of two double values. That is, the result is the argument closer to positive infinity. If the arguments have the same value, the result is that same value. If either value is NaN, then the result is NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. If one argument is positive zero and the other negative zero, the result is positive zero.

Parameters
a double: an argument.

b double: another argument.

Returns
double the larger of a and b.

min

Added in API level 1
public static float min (float a, 
                float b)

Returns the smaller of two float values. That is, the result is the value closer to negative infinity. If the arguments have the same value, the result is that same value. If either value is NaN, then the result is NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. If one argument is positive zero and the other is negative zero, the result is negative zero.

Parameters
a float: an argument.

b float: another argument.

Returns
float the smaller of a and b.

min

Added in API level 1
public static double min (double a, 
                double b)

Returns the smaller of two double values. That is, the result is the value closer to negative infinity. If the arguments have the same value, the result is that same value. If either value is NaN, then the result is NaN. Unlike the numerical comparison operators, this method considers negative zero to be strictly smaller than positive zero. If one argument is positive zero and the other is negative zero, the result is negative zero.

Parameters
a double: an argument.

b double: another argument.

Returns
double the smaller of a and b.

min

Added in API level 1
public static int min (int a, 
                int b)

Returns the smaller of two int values. That is, the result the argument closer to the value of Integer#MIN_VALUE. If the arguments have the same value, the result is that same value.

Parameters
a int: an argument.

b int: another argument.

Returns
int the smaller of a and b.

min

Added in API level 1
public static long min (long a, 
                long b)

Returns the smaller of two long values. That is, the result is the argument closer to the value of Long#MIN_VALUE. If the arguments have the same value, the result is that same value.

Parameters
a long: an argument.

b long: another argument.

Returns
long the smaller of a and b.

multiplyExact

Added in API level 24
public static int multiplyExact (int x, 
                int y)

Returns the product of the arguments, throwing an exception if the result overflows an int.

Parameters
x int: the first value

y int: the second value

Returns
int the result

Throws
ArithmeticException if the result overflows an int

multiplyExact

Added in API level 24
public static long multiplyExact (long x, 
                long y)

Returns the product of the arguments, throwing an exception if the result overflows a long.

Parameters
x long: the first value

y long: the second value

Returns
long the result

Throws
ArithmeticException if the result overflows a long

multiplyExact

Added in API level 31
public static long multiplyExact (long x, 
                int y)

Returns the product of the arguments, throwing an exception if the result overflows a long.

Parameters
x long: the first value

y int: the second value

Returns
long the result

Throws
ArithmeticException if the result overflows a long

multiplyFull

Added in API level 31
public static long multiplyFull (int x, 
                int y)

Returns the exact mathematical product of the arguments.

Parameters
x int: the first value

y int: the second value

Returns
long the result

multiplyHigh

Added in API level 31
public static long multiplyHigh (long x, 
                long y)

Returns as a long the most significant 64 bits of the 128-bit product of two 64-bit factors.

Parameters
x long: the first value

y long: the second value

Returns
long the result

negateExact

Added in API level 24
public static int negateExact (int a)

Returns the negation of the argument, throwing an exception if the result overflows an int. The overflow only occurs for the minimum value.

Parameters
a int: the value to negate

Returns
int the result

Throws
ArithmeticException if the result overflows an int

negateExact

Added in API level 24
public static long negateExact (long a)

Returns the negation of the argument, throwing an exception if the result overflows a long. The overflow only occurs for the minimum value.

Parameters
a long: the value to negate

Returns
long the result

Throws
ArithmeticException if the result overflows a long

nextAfter

Added in API level 9
public static double nextAfter (double start, 
                double direction)

Returns the floating-point number adjacent to the first argument in the direction of the second argument. If both arguments compare as equal the second argument is returned.

Special cases:

  • If either argument is a NaN, then NaN is returned.
  • If both arguments are signed zeros, direction is returned unchanged (as implied by the requirement of returning the second argument if the arguments compare as equal).
  • If start is ±Double#MIN_VALUE and direction has a value such that the result should have a smaller magnitude, then a zero with the same sign as start is returned.
  • If start is infinite and direction has a value such that the result should have a smaller magnitude, Double#MAX_VALUE with the same sign as start is returned.
  • If start is equal to ± Double#MAX_VALUE and direction has a value such that the result should have a larger magnitude, an infinity with same sign as start is returned.

Parameters
start double: starting floating-point value

direction double: value indicating which of start's neighbors or start should be returned

Returns
double The floating-point number adjacent to start in the direction of direction.

nextAfter

Added in API level 9
public static float nextAfter (float start, 
                double direction)

Returns the floating-point number adjacent to the first argument in the direction of the second argument. If both arguments compare as equal a value equivalent to the second argument is returned.

Special cases:

  • If either argument is a NaN, then NaN is returned.
  • If both arguments are signed zeros, a value equivalent to direction is returned.
  • If start is ±Float#MIN_VALUE and direction has a value such that the result should have a smaller magnitude, then a zero with the same sign as start is returned.
  • If start is infinite and direction has a value such that the result should have a smaller magnitude, Float#MAX_VALUE with the same sign as start is returned.
  • If start is equal to ± Float#MAX_VALUE and direction has a value such that the result should have a larger magnitude, an infinity with same sign as start is returned.

Parameters
start float: starting floating-point value

direction double: value indicating which of start's neighbors or start should be returned

Returns
float The floating-point number adjacent to start in the direction of direction.

nextDown

Added in API level 24
public static double nextDown (double d)

Returns the floating-point value adjacent to d in the direction of negative infinity. This method is semantically equivalent to nextAfter(d, Double.NEGATIVE_INFINITY); however, a nextDown implementation may run faster than its equivalent nextAfter call.

Special Cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is negative infinity, the result is negative infinity.
  • If the argument is zero, the result is -Double.MIN_VALUE

Parameters
d double: starting floating-point value

Returns
double The adjacent floating-point value closer to negative infinity.

nextDown

Added in API level 24
public static float nextDown (float f)

Returns the floating-point value adjacent to f in the direction of negative infinity. This method is semantically equivalent to nextAfter(f, Float.NEGATIVE_INFINITY); however, a nextDown implementation may run faster than its equivalent nextAfter call.

Special Cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is negative infinity, the result is negative infinity.
  • If the argument is zero, the result is -Float.MIN_VALUE

Parameters
f float: starting floating-point value

Returns
float The adjacent floating-point value closer to negative infinity.

nextUp

Added in API level 9
public static float nextUp (float f)

Returns the floating-point value adjacent to f in the direction of positive infinity. This method is semantically equivalent to nextAfter(f, Float.POSITIVE_INFINITY); however, a nextUp implementation may run faster than its equivalent nextAfter call.

Special Cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is positive infinity, the result is positive infinity.
  • If the argument is zero, the result is Float#MIN_VALUE

Parameters
f float: starting floating-point value

Returns
float The adjacent floating-point value closer to positive infinity.

nextUp

Added in API level 9
public static double nextUp (double d)

Returns the floating-point value adjacent to d in the direction of positive infinity. This method is semantically equivalent to nextAfter(d, Double.POSITIVE_INFINITY); however, a nextUp implementation may run faster than its equivalent nextAfter call.

Special Cases:

  • If the argument is NaN, the result is NaN.
  • If the argument is positive infinity, the result is positive infinity.
  • If the argument is zero, the result is Double#MIN_VALUE

Parameters
d double: starting floating-point value

Returns
double The adjacent floating-point value closer to positive infinity.

pow

Added in API level 1
public static double pow (double a, 
                double b)

Returns the value of the first argument raised to the power of the second argument. Special cases:

  • If the second argument is positive or negative zero, then the result is 1.0.
  • If the second argument is 1.0, then the result is the same as the first argument.
  • If the first argument is 1.0, then the result is 1.0.
  • If the second argument is NaN, then the result is NaN except where the first argument is 1.0.
  • If the first argument is NaN and the second argument is nonzero, then the result is NaN.
  • If
    • the absolute value of the first argument is greater than 1 and the second argument is positive infinity, or
    • the absolute value of the first argument is less than 1 and the second argument is negative infinity,
    then the result is positive infinity.
  • If
    • the absolute value of the first argument is greater than 1 and the second argument is negative infinity, or
    • the absolute value of the first argument is less than 1 and the second argument is positive infinity,
    then the result is positive zero.
  • If the absolute value of the first argument equals 1 and the second argument is infinite, then the result is 1.0.
  • If
    • the first argument is positive zero and the second argument is greater than zero, or
    • the first argument is positive infinity and the second argument is less than zero,
    then the result is positive zero.
  • If
    • the first argument is positive zero and the second argument is less than zero, or
    • the first argument is positive infinity and the second argument is greater than zero,
    then the result is positive infinity.
  • If
    • the first argument is negative zero and the second argument is greater than zero but not a finite odd integer, or
    • the first argument is negative infinity and the second argument is less than zero but not a finite odd integer,
    then the result is positive zero.
  • If
    • the first argument is negative zero and the second argument is a positive finite odd integer, or
    • the first argument is negative infinity and the second argument is a negative finite odd integer,
    then the result is negative zero.
  • If
    • the first argument is negative zero and the second argument is less than zero but not a finite odd integer, or
    • the first argument is negative infinity and the second argument is greater than zero but not a finite odd integer,
    then the result is positive infinity.
  • If
    • the first argument is negative zero and the second argument is a negative finite odd integer, or
    • the first argument is negative infinity and the second argument is a positive finite odd integer,
    then the result is negative infinity.
  • If the first argument is finite and less than zero
    • if the second argument is a finite even integer, the result is equal to the result of raising the absolute value of the first argument to the power of the second argument
    • if the second argument is a finite odd integer, the result is equal to the negative of the result of raising the absolute value of the first argument to the power of the second argument
    • if the second argument is finite and not an integer, then the result is NaN.
  • If both arguments are integers, then the result is exactly equal to the mathematical result of raising the first argument to the power of the second argument if that result can in fact be represented exactly as a double value.

(In the foregoing descriptions, a floating-point value is considered to be an integer if and only if it is finite and a fixed point of the method ceil or, equivalently, a fixed point of the method floor. A value is a fixed point of a one-argument method if and only if the result of applying the method to the value is equal to the value.)

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

API Note:
  • The special cases definitions of this method differ from the special case definitions of the IEEE 754 recommended pow operation for ±1.0 raised to an infinite power. This method treats such cases as indeterminate and specifies a NaN is returned. The IEEE 754 specification treats the infinite power as a large integer (large-magnitude floating-point numbers are numerically integers, specifically even integers) and therefore specifies 1.0 be returned.
Parameters
a double: the base.

b double: the exponent.

Returns
double the value ab.

random

Added in API level 1
public static double random ()

Returns a double value with a positive sign, greater than or equal to 0.0 and less than 1.0. Returned values are chosen pseudorandomly with (approximately) uniform distribution from that range.

When this method is first called, it creates a single new pseudorandom-number generator, exactly as if by the expression

new java.util.Random()
This new pseudorandom-number generator is used thereafter for all calls to this method and is used nowhere else.

This method is properly synchronized to allow correct use by more than one thread. However, if many threads need to generate pseudorandom numbers at a great rate, it may reduce contention for each thread to have its own pseudorandom-number generator.

API Note:
  • As the largest double value less than 1.0 is Math.nextDown(1.0), a value x in the closed range [x1,x2] where x1<=x2 may be defined by the statements
    double f = Math.random()/Math.nextDown(1.0);
     double x = x1*(1.0 - f) + x2*f;
     
Returns
double a pseudorandom double greater than or equal to 0.0 and less than 1.0.

rint

Added in API level 1
public static double rint (double a)

Returns the double value that is closest in value to the argument and is equal to a mathematical integer. If two double values that are mathematical integers are equally close, the result is the integer value that is even. Special cases:

  • If the argument value is already equal to a mathematical integer, then the result is the same as the argument.
  • If the argument is NaN or an infinity or positive zero or negative zero, then the result is the same as the argument.

Parameters
a double: a double value.

Returns
double the closest floating-point value to a that is equal to a mathematical integer.

round

Added in API level 1
public static long round (double a)

Returns the closest long to the argument, with ties rounding to positive infinity.

Special cases:

  • If the argument is NaN, the result is 0.
  • If the argument is negative infinity or any value less than or equal to the value of Long.MIN_VALUE, the result is equal to the value of Long.MIN_VALUE.
  • If the argument is positive infinity or any value greater than or equal to the value of Long.MAX_VALUE, the result is equal to the value of Long.MAX_VALUE.

Parameters
a double: a floating-point value to be rounded to a long.

Returns
long the value of the argument rounded to the nearest long value.

round

Added in API level 1
public static int round (float a)

Returns the closest int to the argument, with ties rounding to positive infinity.

Special cases:

  • If the argument is NaN, the result is 0.
  • If the argument is negative infinity or any value less than or equal to the value of Integer.MIN_VALUE, the result is equal to the value of Integer.MIN_VALUE.
  • If the argument is positive infinity or any value greater than or equal to the value of Integer.MAX_VALUE, the result is equal to the value of Integer.MAX_VALUE.

Parameters
a float: a floating-point value to be rounded to an integer.

Returns
int the value of the argument rounded to the nearest int value.

scalb

Added in API level 9
public static float scalb (float f, 
                int scaleFactor)

Returns f × 2scaleFactor rounded as if performed by a single correctly rounded floating-point multiply. If the exponent of the result is between Float#MIN_EXPONENT and Float.MAX_EXPONENT, the answer is calculated exactly. If the exponent of the result would be larger than Float.MAX_EXPONENT, an infinity is returned. Note that if the result is subnormal, precision may be lost; that is, when scalb(x, n) is subnormal, scalb(scalb(x, n), -n) may not equal x. When the result is non-NaN, the result has the same sign as f.

Special cases:

  • If the first argument is NaN, NaN is returned.
  • If the first argument is infinite, then an infinity of the same sign is returned.
  • If the first argument is zero, then a zero of the same sign is returned.

Parameters
f float: number to be scaled by a power of two.

scaleFactor int: power of 2 used to scale f

Returns
float f × 2scaleFactor

scalb

Added in API level 9
public static double scalb (double d, 
                int scaleFactor)

Returns d × 2scaleFactor rounded as if performed by a single correctly rounded floating-point multiply. If the exponent of the result is between Double#MIN_EXPONENT and Double.MAX_EXPONENT, the answer is calculated exactly. If the exponent of the result would be larger than Double.MAX_EXPONENT, an infinity is returned. Note that if the result is subnormal, precision may be lost; that is, when scalb(x, n) is subnormal, scalb(scalb(x, n), -n) may not equal x. When the result is non-NaN, the result has the same sign as d.

Special cases:

  • If the first argument is NaN, NaN is returned.
  • If the first argument is infinite, then an infinity of the same sign is returned.
  • If the first argument is zero, then a zero of the same sign is returned.

Parameters
d double: number to be scaled by a power of two.

scaleFactor int: power of 2 used to scale d

Returns
double d × 2scaleFactor

signum

Added in API level 1
public static double signum (double d)

Returns the signum function of the argument; zero if the argument is zero, 1.0 if the argument is greater than zero, -1.0 if the argument is less than zero.

Special Cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is positive zero or negative zero, then the result is the same as the argument.

Parameters
d double: the floating-point value whose signum is to be returned

Returns
double the signum function of the argument

signum

Added in API level 1
public static float signum (float f)

Returns the signum function of the argument; zero if the argument is zero, 1.0f if the argument is greater than zero, -1.0f if the argument is less than zero.

Special Cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is positive zero or negative zero, then the result is the same as the argument.

Parameters
f float: the floating-point value whose signum is to be returned

Returns
float the signum function of the argument

sin

Added in API level 1
public static double sin (double a)

Returns the trigonometric sine of an angle. Special cases:

  • If the argument is NaN or an infinity, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: an angle, in radians.

Returns
double the sine of the argument.

sinh

Added in API level 1
public static double sinh (double x)

Returns the hyperbolic sine of a double value. The hyperbolic sine of x is defined to be (ex - e-x)/2 where e is Euler's number.

Special cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is infinite, then the result is an infinity with the same sign as the argument.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 2.5 ulps of the exact result.

Parameters
x double: The number whose hyperbolic sine is to be returned.

Returns
double The hyperbolic sine of x.

sqrt

Added in API level 1
public static double sqrt (double a)

Returns the correctly rounded positive square root of a double value. Special cases:

  • If the argument is NaN or less than zero, then the result is NaN.
  • If the argument is positive infinity, then the result is positive infinity.
  • If the argument is positive zero or negative zero, then the result is the same as the argument.
Otherwise, the result is the double value closest to the true mathematical square root of the argument value.

Parameters
a double: a value.

Returns
double the positive square root of a. If the argument is NaN or less than zero, the result is NaN.

subtractExact

Added in API level 24
public static long subtractExact (long x, 
                long y)

Returns the difference of the arguments, throwing an exception if the result overflows a long.

Parameters
x long: the first value

y long: the second value to subtract from the first

Returns
long the result

Throws
ArithmeticException if the result overflows a long

subtractExact

Added in API level 24
public static int subtractExact (int x, 
                int y)

Returns the difference of the arguments, throwing an exception if the result overflows an int.

Parameters
x int: the first value

y int: the second value to subtract from the first

Returns
int the result

Throws
ArithmeticException if the result overflows an int

tan

Added in API level 1
public static double tan (double a)

Returns the trigonometric tangent of an angle. Special cases:

  • If the argument is NaN or an infinity, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.

The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.

Parameters
a double: an angle, in radians.

Returns
double the tangent of the argument.

tanh

Added in API level 1
public static double tanh (double x)

Returns the hyperbolic tangent of a double value. The hyperbolic tangent of x is defined to be (ex - e-x)/(ex + e-x), in other words, sinh(x)/cosh(x). Note that the absolute value of the exact tanh is always less than 1.

Special cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.
  • If the argument is positive infinity, then the result is +1.0.
  • If the argument is negative infinity, then the result is -1.0.

The computed result must be within 2.5 ulps of the exact result. The result of tanh for any finite input must have an absolute value less than or equal to 1. Note that once the exact result of tanh is within 1/2 of an ulp of the limit value of ±1, correctly signed ±1.0 should be returned.

Parameters
x double: The number whose hyperbolic tangent is to be returned.

Returns
double The hyperbolic tangent of x.

toDegrees

Added in API level 1
public static double toDegrees (double angrad)

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 not expect cos(toRadians(90.0)) to exactly equal 0.0.

Parameters
angrad double: an angle, in radians

Returns
double the measurement of the angle angrad in degrees.

toIntExact

Added in API level 24
public static int toIntExact (long value)

Returns the value of the long argument, throwing an exception if the value overflows an int.

Parameters
value long: the long value

Returns
int the argument as an int

Throws
ArithmeticException if the argument overflows an int

toRadians

Added in API level 1
public static double toRadians (double angdeg)

Converts an angle measured in degrees to an approximately equivalent angle measured in radians. The conversion from degrees to radians is generally inexact.

Parameters
angdeg double: an angle, in degrees

Returns
double the measurement of the angle angdeg in radians.

ulp

Added in API level 1
public static double ulp (double d)

Returns the size of an ulp of the argument. An ulp, unit in the last place, of a double value is the positive distance between this floating-point value and the double value next larger in magnitude. Note that for non-NaN x, ulp(-x) == ulp(x).

Special Cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is positive or negative infinity, then the result is positive infinity.
  • If the argument is positive or negative zero, then the result is Double.MIN_VALUE.
  • If the argument is ±Double.MAX_VALUE, then the result is equal to 2971.

Parameters
d double: the floating-point value whose ulp is to be returned

Returns
double the size of an ulp of the argument

ulp

Added in API level 1
public static float ulp (float f)

Returns the size of an ulp of the argument. An ulp, unit in the last place, of a float value is the positive distance between this floating-point value and the float value next larger in magnitude. Note that for non-NaN x, ulp(-x) == ulp(x).

Special Cases:

  • If the argument is NaN, then the result is NaN.
  • If the argument is positive or negative infinity, then the result is positive infinity.
  • If the argument is positive or negative zero, then the result is Float.MIN_VALUE.
  • If the argument is ±Float.MAX_VALUE, then the result is equal to 2104.

Parameters
f float: the floating-point value whose ulp is to be returned

Returns
float the size of an ulp of the argument