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java.lang.Object
java.lang.StrictMath
public final class StrictMath
extends Object
Math
, but is 100% portable, because it uses
no native methods whatsoever. Also, these algorithms are all accurate
to less than 1 ulp, and execute in strictfp
mode, while
Math is allowed to vary in its results for some functions. Unfortunately,
this usually means StrictMath has less efficiency and speed, as Math can
use native methods.
The source of the various algorithms used is the fdlibm library, at:
http://www.netlib.org/fdlibm/
Note that angles are specified in radians. Conversion functions are
provided for your convenience.
Field Summary  
static double 

static double 

Method Summary  
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static int 

static long 

static double 

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static float 

static int 

static long 

static double 

static float 

static int 

static long 

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static long 

static int 

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static float 

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static float 

Methods inherited from class java.lang.Object  
clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait 
public static final double E
The most accurate approximation to the mathematical constant e:2.718281828459045
. Used in natural log and exp.
 Field Value:
 2.0
 See Also:
log(double)
,exp(double)
public static final double PI
The most accurate approximation to the mathematical constant pi:3.141592653589793
. This is the ratio of a circle's diameter to its circumference.
 Field Value:
 3.0
public static double IEEEremainder(double x, double y)
Get the IEEE 754 floating point remainder on two numbers. This is the value ofx  y * n
, where n is the closest double tox / y
(ties go to the even n); for a zero remainder, the sign is that ofx
. If either argument is NaN, the first argument is infinite, or the second argument is zero, the result is NaN; if x is finite but y is infinite, the result is x.
 Parameters:
x
 the dividend (the top half)y
 the divisor (the bottom half)
 Returns:
 the IEEE 754defined floating point remainder of x/y
 See Also:
rint(double)
public static double abs(double d)
Take the absolute value of the argument. (Absolute value means make it positive.)
 Parameters:
d
 the number to take the absolute value of
 Returns:
 the absolute value
public static float abs(float f)
Take the absolute value of the argument. (Absolute value means make it positive.)
 Parameters:
f
 the number to take the absolute value of
 Returns:
 the absolute value
public static int abs(int i)
Take the absolute value of the argument. (Absolute value means make it positive.)Note that the the largest negative value (Integer.MIN_VALUE) cannot be made positive. In this case, because of the rules of negation in a computer, MIN_VALUE is what will be returned. This is a negative value. You have been warned.
 Parameters:
i
 the number to take the absolute value of
 Returns:
 the absolute value
 See Also:
Integer.MIN_VALUE
public static long abs(long l)
Take the absolute value of the argument. (Absolute value means make it positive.)Note that the the largest negative value (Long.MIN_VALUE) cannot be made positive. In this case, because of the rules of negation in a computer, MIN_VALUE is what will be returned. This is a negative value. You have been warned.
 Parameters:
l
 the number to take the absolute value of
 Returns:
 the absolute value
 See Also:
Long.MIN_VALUE
public static double acos(double x)
The trigonometric function arccos. The range of angles returned is 0 to pi radians (0 to 180 degrees). If the argument is NaN or its absolute value is beyond 1, the result is NaN.
 Parameters:
x
 the cos to turn back into an angle
 Returns:
 arccos(x)
public static double asin(double x)
The trigonometric function arcsin. The range of angles returned is pi/2 to pi/2 radians (90 to 90 degrees). If the argument is NaN or its absolute value is beyond 1, the result is NaN; and the arcsine of 0 retains its sign.
 Parameters:
x
 the sin to turn back into an angle
 Returns:
 arcsin(x)
public static double atan(double x)
The trigonometric function arcsin. The range of angles returned is pi/2 to pi/2 radians (90 to 90 degrees). If the argument is NaN, the result is NaN; and the arctangent of 0 retains its sign.
 Parameters:
x
 the tan to turn back into an angle
 Returns:
 arcsin(x)
 See Also:
atan2(double,double)
public static double atan2(double y, double x)
A special version of the trigonometric function arctan, for converting rectangular coordinates (x, y) to polar (r, theta). This computes the arctangent of x/y in the range of pi to pi radians (180 to 180 degrees). Special cases:
 If either argument is NaN, 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.
This returns theta, the angle of the point. To get r, albeit slightly inaccurately, use sqrt(x*x+y*y).
 Parameters:
y
 the y positionx
 the x position
 Returns:
 theta in the conversion of (x, y) to (r, theta)
 See Also:
atan(double)
public static double cbrt(double x)
Returns the cube root ofx
. The sign of the cube root is equal to the sign ofx
. 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 negative infinity, the result is negative infinity.
 If the argument is zero, the result is zero with the same sign as the argument.
 Parameters:
x
 the number to take the cube root of
 Returns:
 the cube root of
x
 Since:
 1.5
 See Also:
sqrt(double)
public static double ceil(double a)
Take the nearest integer that is that is greater than or equal to the argument. If the argument is NaN, infinite, or zero, the result is the same; if the argument is between 1 and 0, the result is negative zero. Note thatMath.ceil(x) == Math.floor(x)
.
 Parameters:
a
 the value to act upon
 Returns:
 the nearest integer >=
a
public static double cos(double a)
The trigonometric function cos. The cosine of NaN or infinity is NaN.
 Parameters:
a
 the angle (in radians).
 Returns:
 cos(a).
public static double cosh(double x)
Returns the hyperbolic cosine ofx
, which is defined as (exp(x) + exp(x)) / 2. 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 negative infinity, the result is positive infinity.
 If the argument is zero, the result is one.
 Parameters:
x
 the argument to cosh
 Returns:
 the hyperbolic cosine of
x
 Since:
 1.5
public static double exp(double x)
Take e^{a}. The opposite oflog()
. If the argument is NaN, the result is NaN; if the argument is positive infinity, the result is positive infinity; and if the argument is negative infinity, the result is positive zero.
 Parameters:
x
 the number to raise to the power
 Returns:
 the number raised to the power of e
 See Also:
log(double)
,pow(double,double)
public static double expm1(double x)
Returns e^{x}  1. 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 negative infinity, the result is 1.
 If the argument is zero, the result is zero.
 Parameters:
x
 the argument to e^{x}  1.
 Returns:
 e raised to the power
x
minus one.
 See Also:
exp(double)
public static double floor(double a)
Take the nearest integer that is that is less than or equal to the argument. If the argument is NaN, infinite, or zero, the result is the same. Note thatMath.ceil(x) == Math.floor(x)
.
 Parameters:
a
 the value to act upon
 Returns:
 the nearest integer <=
a
public static double log(double x)
Take ln(a) (the natural log). The opposite ofexp()
. If the argument is NaN or negative, the result is NaN; if the argument is positive infinity, the result is positive infinity; and if the argument is either zero, the result is negative infinity.Note that the way to get log_{b}(a) is to do this:
ln(a) / ln(b)
.
 Parameters:
x
 the number to take the natural log of
 Returns:
 the natural log of
a
 See Also:
exp(double)
public static double max(double a, double b)
Return whichever argument is larger. If either argument is NaN, the result is NaN, and when comparing 0 and 0, 0 is always larger.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the larger of the two numbers
public static float max(float a, float b)
Return whichever argument is larger. If either argument is NaN, the result is NaN, and when comparing 0 and 0, 0 is always larger.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the larger of the two numbers
public static int max(int a, int b)
Return whichever argument is larger.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the larger of the two numbers
public static long max(long a, long b)
Return whichever argument is larger.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the larger of the two numbers
public static double min(double a, double b)
Return whichever argument is smaller. If either argument is NaN, the result is NaN, and when comparing 0 and 0, 0 is always smaller.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the smaller of the two numbers
public static float min(float a, float b)
Return whichever argument is smaller. If either argument is NaN, the result is NaN, and when comparing 0 and 0, 0 is always smaller.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the smaller of the two numbers
public static int min(int a, int b)
Return whichever argument is smaller.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the smaller of the two numbers
public static long min(long a, long b)
Return whichever argument is smaller.
 Parameters:
a
 the first numberb
 a second number
 Returns:
 the smaller of the two numbers
public static double pow(double x, double y)
Raise a number to a power. 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 second argument is NaN, then the result is NaN.
 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 NaN.
 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 less than zero and the second argument is a finite even integer, then 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 first argument is less than zero and the second argument is a finite odd integer, then 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 first argument is finite and less than zero and 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 floatingpoint value is considered to be an integer if and only if it is a fixed point of the method
ceil(double)
or, equivalently, a fixed point of the methodfloor(double)
. A value is a fixed point of a oneargument method if and only if the result of applying the method to the value is equal to the value.)
 Parameters:
x
 the number to raisey
 the power to raise it to
 Returns:
 x^{y}
public static double random()
Get a random number. This behaves like Random.nextDouble(), seeded by System.currentTimeMillis() when first called. In other words, the number is from a pseudorandom sequence, and lies in the range [+0.0, 1.0). This random sequence is only used by this method, and is threadsafe, although you may want your own random number generator if it is shared among threads.
 Returns:
 a random number
public static double rint(double a)
Take the nearest integer to the argument. If it is exactly between two integers, the even integer is taken. If the argument is NaN, infinite, or zero, the result is the same.
 Parameters:
a
 the value to act upon
 Returns:
 the nearest integer to
a
public static long round(double d)
Take the nearest long to the argument. This is equivalent to(long) Math.floor(d + 0.5)
. If the argument is NaN, the result is 0; otherwise if the argument is outside the range of long, the result will be Long.MIN_VALUE or Long.MAX_VALUE, as appropriate.
 Parameters:
d
 the argument to round
 Returns:
 the nearest long to the argument
 See Also:
Long.MIN_VALUE
,Long.MAX_VALUE
public static int round(float f)
Take the nearest integer to the argument. This is equivalent to(int) Math.floor(f + 0.5f)
. If the argument is NaN, the result is 0; otherwise if the argument is outside the range of int, the result will be Integer.MIN_VALUE or Integer.MAX_VALUE, as appropriate.
 Parameters:
f
 the argument to round
 Returns:
 the nearest integer to the argument
 See Also:
Integer.MIN_VALUE
,Integer.MAX_VALUE
public static double signum(double a)
Returns the sign of the argument as follows:
 If
a
is greater than zero, the result is 1.0. If
a
is less than zero, the result is 1.0. If
a
isNaN
, the result isNaN
. If
a
is positive or negative zero, the result is the same.
 Parameters:
a
 the numeric argument.
 Returns:
 the sign of the argument.
 Since:
 1.5.
public static float signum(float a)
Returns the sign of the argument as follows:
 If
a
is greater than zero, the result is 1.0f. If
a
is less than zero, the result is 1.0f. If
a
isNaN
, the result isNaN
. If
a
is positive or negative zero, the result is the same.
 Parameters:
a
 the numeric argument.
 Returns:
 the sign of the argument.
 Since:
 1.5.
public static double sin(double a)
The trigonometric function sin. The sine of NaN or infinity is NaN, and the sine of 0 retains its sign.
 Parameters:
a
 the angle (in radians)
 Returns:
 sin(a)
public static double sinh(double x)
Returns the hyperbolic sine ofx
which is defined as (exp(x)  exp(x)) / 2. 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 negative infinity, the result is negative infinity.
 If the argument is zero, the result is zero.
 Parameters:
x
 the argument to sinh
 Returns:
 the hyperbolic sine of
x
 Since:
 1.5
public static double sqrt(double x)
Take a square root. If the argument is NaN or negative, the result is NaN; if the argument is positive infinity, the result is positive infinity; and if the result is either zero, the result is the same.For other roots, use pow(x, 1/rootNumber).
 Parameters:
x
 the numeric argument
 Returns:
 the square root of the argument
 See Also:
pow(double,double)
public static double tan(double a)
The trigonometric function tan. The tangent of NaN or infinity is NaN, and the tangent of 0 retains its sign.
 Parameters:
a
 the angle (in radians)
 Returns:
 tan(a)
public static double tanh(double x)
Returns the hyperbolic tangent ofx
, which is defined as (exp(x)  exp(x)) / (exp(x) + exp(x)), i.e. sinh(x) / cosh(x). Special cases:
 If the argument is NaN, the result is NaN
 If the argument is positive infinity, the result is 1.
 If the argument is negative infinity, the result is 1.
 If the argument is zero, the result is zero.
 Parameters:
x
 the argument to tanh
 Returns:
 the hyperbolic tagent of
x
 Since:
 1.5
public static double toDegrees(double rads)
Convert from radians to degrees. The formula for this is degrees = radians * (180/pi); however it is not always exact given the limitations of floating point numbers.
 Parameters:
rads
 an angle in radians
 Returns:
 the angle in degrees
public static double toRadians(double degrees)
Convert from degrees to radians. The formula for this is radians = degrees * (pi/180); however it is not always exact given the limitations of floating point numbers.
 Parameters:
degrees
 an angle in degrees
 Returns:
 the angle in radians
public static double ulp(double d)
Return the ulp for the given double argument. The ulp is the difference between the argument and the next larger double. Note that the sign of the double argument is ignored, that is, ulp(x) == ulp(x). If the argument is a NaN, then NaN is returned. If the argument is an infinity, then +Inf is returned. If the argument is zero (either positive or negative), thenDouble.MIN_VALUE
is returned.
 Parameters:
d
 the double whose ulp should be returned
 Returns:
 the difference between the argument and the next larger double
 Since:
 1.5
public static float ulp(float f)
Return the ulp for the given float argument. The ulp is the difference between the argument and the next larger float. Note that the sign of the float argument is ignored, that is, ulp(x) == ulp(x). If the argument is a NaN, then NaN is returned. If the argument is an infinity, then +Inf is returned. If the argument is zero (either positive or negative), thenFloat.MIN_VALUE
is returned.
 Parameters:
f
 the float whose ulp should be returned
 Returns:
 the difference between the argument and the next larger float
 Since:
 1.5
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