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JavaTM 2 Platform Standard Edition |
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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
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.
To help ensure portability of Java programs, the definitions of
many 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 network library may be found on the World Wide Web at:
http://metalab.unc.edu/
The Java math library is defined with respect to the version of
fdlibm
dated January 4, 1995. 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
).
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(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 an angle, in the range of 0.0 through pi. |
static double |
asin(double a)
Returns the arc sine of an angle, in the range of -pi/2 through pi/2. |
static double |
atan(double a)
Returns the arc tangent of an angle, in the range of -pi/2 through pi/2. |
static double |
atan2(double a,
double b)
Converts rectangular coordinates ( b , a )
to polar (r, theta). |
static double |
ceil(double a)
Returns the smallest (closest to negative infinity) double value that is not less than the argument and is
equal to a mathematical integer. |
static double |
cos(double a)
Returns the trigonometric cosine of an angle. |
static double |
exp(double a)
Returns the exponential number e (i.e., 2.718...) raised to the power of a double value. |
static double |
floor(double a)
Returns the largest (closest to positive infinity) double value that is not greater than the argument and
is equal to a mathematical integer. |
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 |
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 double |
pow(double a,
double b)
Returns of value of the first argument raised to the power of the second argument. |
static double |
random()
Returns a random number greater than or equal to 0.0
and less than 1.0 . |
static double |
rint(double a)
returns the closest integer to the argument. |
static long |
round(double a)
Returns the closest long to the argument. |
static int |
round(float a)
Returns the closest int to the argument. |
static double |
sin(double a)
Returns the trigonometric sine of an angle. |
static double |
sqrt(double a)
Returns the square root of a double value. |
static double |
tan(double a)
Returns the trigonometric tangent of an angle. |
static double |
toDegrees(double angrad)
Converts an angle measured in radians to the equivalent angle measured in degrees. |
static double |
toRadians(double angdeg)
Converts an angle measured in degrees to the equivalent angle measured in radians. |
Methods inherited from class java.lang.Object |
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait |
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)
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 double
value whose arc sine is to
be returned.public static double acos(double a)
a
- the double
value whose arc cosine is to
be returned.public static double atan(double a)
a
- the double
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)
angrad
- an angle, in radiansangrad
in degrees.public static double exp(double a)
double
value.a
- a double
value.public static double log(double a)
double
value.a
- a number greater than 0.0
.a
, the natural logarithm of
a
.public static double sqrt(double a)
double
value.a
- a double
value.
a
.
If the argument is NaN or less than zero, the result is NaN.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.f1
- the dividend.f2
- the divisor.f1
is divided by
f2
.public static double ceil(double a)
double
value that is not less than the argument and is
equal to a mathematical integer.a
- a double
value.
double
value that is not less than the argument
and is equal to a mathematical integer.public static double floor(double a)
double
value that is not greater than the argument and
is equal to a mathematical integer.a
- a double
value.a
- an assigned value.
double
value that is not greater than the argument
and is equal to a mathematical integer.public static double rint(double a)
a
- a double
value.double
value to a
that 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.public static double atan2(double a, double b)
b
, a
)
to polar (r, theta).
This method computes the phase theta by computing an arc tangent
of a/b
in the range of -pi to pi.a
- a double
value.b
- a double
value.public static double pow(double a, double b)
If (a == 0.0
), then b
must be
greater than 0.0
; otherwise an exception is thrown.
An exception also will occur if (a <= 0.0
)
and b
is not equal to a whole number.
a
- a double
value.b
- a double
value.ab
.a == 0.0
) and
(b <= 0.0
), or
if (a <= 0.0
) and b
is not equal to a whole number.public static int round(float a)
int
to the argument.
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
.
a
- a float
value.int
value.Integer.MAX_VALUE
,
Integer.MIN_VALUE
public static long round(double a)
long
to the argument.
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
.
a
- a double
value.long
value.Long.MAX_VALUE
,
Long.MIN_VALUE
public static double random()
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
- an int
value.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
- a long
value.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.a
- a float
value.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.a
- a double
value.public static int max(int a, int b)
int
values.a
- an int
value.b
- an int
value.a
and b
.public static long max(long a, long b)
long
values.a
- a long
value.b
- a long
value.a
and b
.public static float max(float a, float b)
float
values. If either value
is NaN
, then the result is NaN
. Unlike the
the numerical comparison operators, this method considers negative zero
to be strictly smaller than positive zero.a
- a float
value.b
- a float
value.a
and b
.public static double max(double a, double b)
double
values. If either value
is NaN
, then the result is NaN
. Unlike the
the numerical comparison operators, this method considers negative zero
to be strictly smaller than positive zero.a
- a double
value.b
- a double
value.a
and b
.public static int min(int a, int b)
int
values.a
- an int
value.b
- an int
value.a
and b
.public static long min(long a, long b)
long
values.a
- a long
value.b
- a long
value.a
and b
.public static float min(float a, float b)
float
values. If either value
is NaN
, then the result is NaN
. Unlike the
the numerical comparison operators, this method considers negative zero
to be strictly smaller than positive zero.a
- a float
value.b
- a float
value.a
and b.
public static double min(double a, double b)
double
values. If either value
is NaN
, then the result is NaN
. Unlike the
the numerical comparison operators, this method considers negative zero
to be strictly smaller than positive zero.a
- a double
value.b
- a double
value.a
and b
.
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JavaTM 2 Platform Standard Edition |
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PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |