public final class StrictMath extends Object
StrictMath contains methods for performing basic
numeric operations such as the elementary exponential, logarithm,
square root, and trigonometric functions.
To help ensure portability of Java programs, the definitions of
some of the numeric functions in this package require that they
produce the same results as certain published algorithms. These
algorithms are available from the well-known network library
netlib as the package "Freely Distributable Math
Library," fdlibm. These
algorithms, which are written in the C programming language, are
then to be understood as executed with all floating-point
operations following the rules of Java floating-point arithmetic.
The Java math library is defined with respect to
fdlibm version 5.3. Where fdlibm provides
more than one definition for a function (such as
acos), use the "IEEE 754 core function" version
(residing in a file whose name begins with the letter
e). The methods which require fdlibm
semantics are sin, cos, tan,
asin, acos, atan,
exp, log, log10,
cbrt, atan2, pow,
sinh, cosh, tanh,
hypot, expm1, and log1p.
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, and toIntExact
throw an ArithmeticException when the results overflow.
For other arithmetic operations such as divide, absolute value,
increment, decrement, and negation overflow occurs only with
a specific minimum or maximum value and should be checked against
the minimum or maximum as appropriate.
| Modifier and Type | Field and Description |
|---|---|
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. |
| Modifier and Type | Method and Description |
|---|---|
static double |
abs(double a)
Returns the absolute value of a
double value. |
static float |
abs(float a)
Returns the absolute value of a
float value. |
static int |
abs(int a)
Returns the absolute value of an
int value. |
static long |
abs(long a)
Returns the absolute value of a
long value. |
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 (
x, y) 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 double |
copySign(double magnitude,
double sign)
Returns the first floating-point argument with the sign of the
second floating-point argument.
|
static float |
copySign(float magnitude,
float 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 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 int |
floorMod(int x,
int y)
Returns the floor modulus of the
int arguments. |
static long |
floorMod(long x,
long y)
Returns the floor modulus of the
long arguments. |
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 double |
IEEEremainder(double f1,
double f2)
Computes the remainder operation on two arguments as prescribed
by the IEEE 754 standard.
|
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 double |
max(double a,
double b)
Returns the greater of two
double values. |
static float |
max(float a,
float b)
Returns the greater of two
float values. |
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 double |
min(double a,
double b)
Returns the smaller of two
double values. |
static float |
min(float a,
float b)
Returns the smaller of two
float 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 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 double |
nextUp(double d)
Returns the floating-point value adjacent to
d in
the direction of positive infinity. |
static float |
nextUp(float f)
Returns the floating-point value adjacent to
f 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 double |
scalb(double d,
int scaleFactor)
Returns
d ×
2scaleFactor rounded as if performed
by a single correctly rounded floating-point multiply to a
member of the double value set. |
static float |
scalb(float f,
int scaleFactor)
Returns
f ×
2scaleFactor rounded as if performed
by a single correctly rounded floating-point multiply to a
member of the float value set. |
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 int |
subtractExact(int x,
int y)
Returns the difference of the arguments,
throwing an exception if the result overflows an
int. |
static long |
subtractExact(long x,
long y)
Returns the difference of the arguments,
throwing an exception if the result overflows a
long. |
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.
|
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.public static double sin(double a)
a - an angle, in radians.public static double cos(double a)
a - an angle, in radians.public static double tan(double a)
a - an angle, in radians.public static double asin(double a)
a - the value whose arc sine is to be returned.public static double acos(double a)
a - the value whose arc cosine is to be returned.public static double atan(double a)
a - the value whose arc tangent is to be returned.public static double toRadians(double angdeg)
angdeg - an angle, in degreesangdeg
in radians.public static double toDegrees(double angrad)
cos(toRadians(90.0)) to exactly
equal 0.0.angrad - an angle, in radiansangrad
in degrees.public static double exp(double a)
double value. Special cases:
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:
a - a valuea, the natural logarithm of
a.public static double log10(double a)
double value.
Special cases:
a - a valuea.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.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:
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:
StrictMath.ceil(x) is exactly the
value of -StrictMath.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 to the value of the argument, the result is the
integer value that is even. Special cases:
a - a value.a that is
equal to a mathematical integer.public static double atan2(double y,
double x)
x, y) 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:
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.y - the ordinate coordinatex - the abscissa coordinatepublic 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.)
a - base.b - the exponent.ab.public static int round(float a)
int to the argument, with ties
rounding to positive infinity.
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_VALUEpublic static long round(double a)
long to the argument, with ties
rounding to positive infinity.
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_VALUEpublic 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
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.
double greater than or equal
to 0.0 and less than 1.0.Random.nextDouble()public static int addExact(int x,
int y)
int.x - the first valuey - the second valueArithmeticException - if the result overflows an intMath.addExact(int,int)public static long addExact(long x,
long y)
long.x - the first valuey - the second valueArithmeticException - if the result overflows a longMath.addExact(long,long)public static int subtractExact(int x,
int y)
int.x - the first valuey - the second value to subtract from the firstArithmeticException - if the result overflows an intMath.subtractExact(int,int)public static long subtractExact(long x,
long y)
long.x - the first valuey - the second value to subtract from the firstArithmeticException - if the result overflows a longMath.subtractExact(long,long)public static int multiplyExact(int x,
int y)
int.x - the first valuey - the second valueArithmeticException - if the result overflows an intMath.multiplyExact(int,int)public static long multiplyExact(long x,
long y)
long.x - the first valuey - the second valueArithmeticException - if the result overflows a longMath.multiplyExact(long,long)public static int toIntExact(long value)
long argument;
throwing an exception if the value overflows an int.value - the long valueArithmeticException - if the argument overflows an intMath.toIntExact(long)public static int floorDiv(int x,
int y)
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 the Integer.MIN_VALUE.
See Math.floorDiv for examples and
a comparison to the integer division / operator.
x - the dividendy - the divisorint value that is less than or equal to the algebraic quotient.ArithmeticException - if the divisor y is zeroMath.floorDiv(int, int),
Math.floor(double)public static long floorDiv(long x,
long y)
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 the Long.MIN_VALUE.
See Math.floorDiv for examples and
a comparison to the integer division / operator.
x - the dividendy - the divisorlong value that is less than or equal to the algebraic quotient.ArithmeticException - if the divisor y is zeroMath.floorDiv(long, long),
Math.floor(double)public static int floorMod(int x,
int y)
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
See Math.floorMod for examples and
a comparison to the % operator.
x - the dividendy - the divisorx - (floorDiv(x, y) * y)ArithmeticException - if the divisor y is zeroMath.floorMod(int, int),
floorDiv(int, int)public static long floorMod(long x,
long y)
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
See Math.floorMod for examples and
a comparison to the % operator.
x - the dividendy - the divisorx - (floorDiv(x, y) * y)ArithmeticException - if the divisor y is zeroMath.floorMod(long, long),
floorDiv(long, long)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.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.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 determinedpublic 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 determinedpublic 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.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.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.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.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 returnedpublic 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 returnedpublic static double signum(double d)
Special Cases:
d - the floating-point value whose signum is to be returnedpublic static float signum(float f)
Special Cases:
f - the floating-point value whose signum is to be returnedpublic 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:
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.
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.
x - The number whose hyperbolic tangent is to be returned.x.public static double hypot(double x,
double y)
Special cases:
x - a valuey - a valuepublic static double expm1(double x)
expm1(x) + 1 is much closer to the true
result of ex than exp(x).
Special cases:
x - the exponent to raise e to in the computation of
ex -1.x - 1.public static double log1p(double x)
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:
x - a valuex + 1), the natural
log of x + 1public static double copySign(double magnitude,
double sign)
sign argument is always treated as if it were
positive.magnitude - the parameter providing the magnitude of the resultsign - the parameter providing the sign of the resultmagnitude
and the sign of sign.public static float copySign(float magnitude,
float sign)
sign argument is always treated as if it were
positive.magnitude - the parameter providing the magnitude of the resultsign - the parameter providing the sign of the resultmagnitude
and the sign of sign.public static int getExponent(float f)
float. Special cases:
Float.MAX_EXPONENT + 1.
Float.MIN_EXPONENT -1.
f - a float valuepublic static int getExponent(double d)
double. Special cases:
Double.MAX_EXPONENT + 1.
Double.MIN_EXPONENT -1.
d - a double valuepublic static double nextAfter(double start,
double direction)
Special cases:
direction
is returned unchanged (as implied by the requirement of
returning the second argument if the arguments compare as
equal).
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.
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.
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.
start - starting floating-point valuedirection - value indicating which of
start's neighbors or start should
be returnedstart in the
direction of direction.public static float nextAfter(float start,
double direction)
Special cases:
direction is returned.
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.
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.
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.
start - starting floating-point valuedirection - value indicating which of
start's neighbors or start should
be returnedstart in the
direction of direction.public static double nextUp(double d)
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:
Double.MIN_VALUE
d - starting floating-point valuepublic static float nextUp(float f)
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:
Float.MIN_VALUE
f - starting floating-point valuepublic static double nextDown(double d)
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:
-Double.MIN_VALUE
d - starting floating-point valuepublic static float nextDown(float f)
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:
-Float.MIN_VALUE
f - starting floating-point valuepublic static double scalb(double d,
int scaleFactor)
d ×
2scaleFactor rounded as if performed
by a single correctly rounded floating-point multiply to a
member of the double value set. See the Java
Language Specification for a discussion of floating-point
value sets. 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:
d - number to be scaled by a power of two.scaleFactor - power of 2 used to scale dd × 2scaleFactorpublic static float scalb(float f,
int scaleFactor)
f ×
2scaleFactor rounded as if performed
by a single correctly rounded floating-point multiply to a
member of the float value set. See the Java
Language Specification for a discussion of floating-point
value sets. 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:
f - number to be scaled by a power of two.scaleFactor - power of 2 used to scale ff × 2scaleFactor Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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