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java.lang.Object![]()
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java.lang.Math
public final class 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.
| Field Summary | |
|---|---|
static double |
E
The double value that is closer than any other to
e, the base of the natural logarithms. |
static double |
PI
The double value that is closer than any other to
pi, the ratio of the circumference of a circle to its
diameter. |
| Method Summary | |
|---|---|
static double |
abs
Returns the absolute value of a double value. |
static float |
abs
Returns the absolute value of a float value. |
static int |
abs
Returns the absolute value of an int value. |
static long |
abs
Returns the absolute value of a long value. |
static double |
acos
Returns the arc cosine of an angle, in the range of 0.0 through pi. |
static double |
asin
Returns the arc sine of an angle, in the range of -pi/2 through pi/2. |
static double |
atan
Returns the arc tangent of an angle, in the range of -pi/2 through pi/2. |
static double |
atan2
Converts rectangular coordinates ( x, y)
to polar (r, theta). |
static double |
cbrt
Returns the cube root of a double value. |
static double |
ceil
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 double |
cos
Returns the trigonometric cosine of an angle. |
static double |
cosh
Returns the hyperbolic cosine of a double value. |
static double |
exp
Returns Euler's number e raised to the power of a double value. |
static double |
expm1
Returns ex -1. |
static double |
floor
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 double |
hypot
Returns sqrt(x2 +y2) without intermediate overflow or underflow. |
static double |
IEEEremainder
Computes the remainder operation on two arguments as prescribed by the IEEE 754 standard. |
static double |
log
Returns the natural logarithm (base e) of a double
value. |
static double |
log10
Returns the base 10 logarithm of a double value. |
static double |
log1p
Returns the natural logarithm of the sum of the argument and 1. |
static double |
max
Returns the greater of two double values. |
static float |
max
Returns the greater of two float values. |
static int |
max
Returns the greater of two int values. |
static long |
max
Returns the greater of two long values. |
static double |
min
Returns the smaller of two double values. |
static float |
min
Returns the smaller of two float values. |
static int |
min
Returns the smaller of two int values. |
static long |
min
Returns the smaller of two long values. |
static double |
pow
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
Returns the double value that is closest in value
to the argument and is equal to a mathematical integer. |
static long |
round
Returns the closest long to the argument. |
static int |
round
Returns the closest int to the argument. |
static double |
signum
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
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
Returns the trigonometric sine of an angle. |
static double |
sinh
Returns the hyperbolic sine of a double value. |
static double |
sqrt
Returns the correctly rounded positive square root of a double value. |
static double |
tan
Returns the trigonometric tangent of an angle. |
static double |
tanh
Returns the hyperbolic tangent of a double value. |
static double |
toDegrees
Converts an angle measured in radians to an approximately equivalent angle measured in degrees. |
static double |
toRadians
Converts an angle measured in degrees to an approximately equivalent angle measured in radians. |
static double |
ulp
Returns the size of an ulp of the argument. |
static float |
ulp
Returns the size of an ulp of the argument. |
Methods inherited from class java.lang.Object ![]() |
|---|
clone |
| Field Detail |
|---|

public static final double E
double value that is closer than any other to
e, the base of the natural logarithms.

public static final double PI
double value that is closer than any other to
pi, the ratio of the circumference of a circle to its
diameter.
| Method Detail |
|---|

public static double sin(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - an angle, in radians.

public static double cos(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - an angle, in radians.

public static double tan(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - an angle, in radians.

public static double asin(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - the value whose arc sine is to be returned.

public static double acos(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - the value whose arc cosine is to be returned.

public static double atan(double a)
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - the value whose arc tangent is to be returned.

public static double toRadians(double angdeg)
angdeg - an angle, in degrees
angdeg
in radians.

public static double toDegrees(double angrad)
cos(toRadians(90.0)) to exactly
equal 0.0.
angrad - an angle, in radians
angrad
in degrees.

public static double exp(double a)
double value. Special cases:
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - the exponent to raise e to.
a,
where e is the base of the natural logarithms.

public static double log(double a)
double
value. Special cases:
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - a value
a, the natural logarithm of
a.

public static double log10(double a)
double value.
Special cases:
The computed result must be within 1 ulp of the exact result. Results must be semi-monotonic.
a - a value
a.

public static double sqrt(double a)
double value.
Special cases:
double value closest to
the true mathematical square root of the argument value.
a - a value.
a.
If the argument is NaN or less than zero, the result is NaN.

public static double cbrt(double 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:
The computed result must be within 1 ulp of the exact result.
a - a value.
a.

public static double IEEEremainder(double f1,
double f2)
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:
f1 - the dividend.f2 - the divisor.
f1 is divided by
f2.

public static double ceil(double a)
double value that is greater than or equal to the
argument and is equal to a mathematical integer. Special cases:
Math.ceil(x) is exactly the
value of -Math.floor(-x).
a - a value.

public static double floor(double a)
double value that is less than or equal to the
argument and is equal to a mathematical integer. Special cases:
a - a value.

public static double rint(double a)
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:
a - a double value.
a that is
equal to a mathematical integer.

public static double atan2(double y,
double x)
x, y)
to polar (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:
double value closest to pi.
double value closest to -pi.
double value closest to pi/2.
double value closest to -pi/2.
double value closest to pi/4.
double
value closest to 3*pi/4.
double value
closest to -pi/4.
double value closest to -3*pi/4.The computed result must be within 2 ulps of the exact result. Results must be semi-monotonic.
y - the ordinate coordinatex - the abscissa coordinate

public static double pow(double a,
double b)
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.
a - the base.b - the exponent.
ab.

public static int round(float a)
int to the argument. The
result is rounded to an integer by adding 1/2, taking the
floor of the result, and casting the result to type int.
In other words, the result is equal to the value of the expression:
(int)Math.floor(a + 0.5f)
Special cases:
Integer.MIN_VALUE, the result is
equal to the value of Integer.MIN_VALUE.
Integer.MAX_VALUE, the result is
equal to the value of Integer.MAX_VALUE.
a - a floating-point value to be rounded to an integer.
int value.Integer.MAX_VALUE
,
Integer.MIN_VALUE


public static long round(double a)
long to the argument. The result
is rounded to an integer by adding 1/2, taking the floor of the
result, and casting the result to type long. In other
words, the result is equal to the value of the expression:
(long)Math.floor(a + 0.5d)
Special cases:
Long.MIN_VALUE, the result is
equal to the value of Long.MIN_VALUE.
Long.MAX_VALUE, the result is
equal to the value of Long.MAX_VALUE.
a - a floating-point value to be rounded to a
long.
long value.Long.MAX_VALUE
,
Long.MIN_VALUE


public static double random()
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
This new pseudorandom-number generator is used thereafter for all calls to this method and is used nowhere else.new java.util.Random
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.
double greater than or equal
to 0.0 and less than 1.0.Random.nextDouble()


public static int abs(int a)
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.
a - the argument whose absolute value is to be determined
Integer.MIN_VALUE


public static long abs(long 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.
a - the argument whose absolute value is to be determined
Long.MIN_VALUE


public static float abs(float 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:
Float.intBitsToFloat(0x7fffffff & Float.floatToIntBits(a))
a - the argument whose absolute value is to be determined

public static double abs(double 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:
Double.longBitsToDouble((Double.doubleToLongBits(a)<<1)>>>1)
a - the argument whose absolute value is to be determined

public static int max(int a,
int b)
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.
a - an argument.b - another argument.
a and b.Long.MAX_VALUE


public static long max(long a,
long b)
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.
a - an argument.b - another argument.
a and b.Long.MAX_VALUE


public static float max(float a,
float b)
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.
a - an argument.b - another argument.
a and b.

public static double max(double a,
double b)
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.
a - an argument.b - another argument.
a and b.

public static int min(int a,
int b)
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.
a - an argument.b - another argument.
a and b.Long.MIN_VALUE


public static long min(long a,
long b)
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.
a - an argument.b - another argument.
a and b.Long.MIN_VALUE


public static float min(float a,
float b)
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.
a - an argument.b - another argument.
a and b.

public static double min(double a,
double b)
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.
a - an argument.b - another argument.
a and b.

public static double ulp(double d)
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:
Double.MIN_VALUE.
Double.MAX_VALUE, then
the result is equal to 2971.
d - the floating-point value whose ulp is to be returned

public static float ulp(float f)
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:
Float.MIN_VALUE.
Float.MAX_VALUE, then
the result is equal to 2104.
f - the floating-point value whose ulp is to be returned

public static double signum(double d)
Special Cases:
d - the floating-point value whose signum is to be returned

public static float signum(float f)
Special Cases:
f - the floating-point value whose signum is to be returned

public static double sinh(double x)
double value.
The hyperbolic sine of x is defined to be
(ex - e-x)/2
where e is Euler's number
.
Special cases:
The computed result must be within 2.5 ulps of the exact result.
x - The number whose hyperbolic sine is to be returned.
x.

public static double cosh(double x)
double value.
The hyperbolic cosine of x is defined to be
(ex + e-x)/2
where e is Euler's number
.
Special cases:
1.0.
The computed result must be within 2.5 ulps of the exact result.
x - The number whose hyperbolic cosine is to be returned.
x.

public static double tanh(double x)
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:
+1.0.
-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.
x - The number whose hyperbolic tangent is to be returned.
x.

public static double hypot(double x,
double y)
Special cases:
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.