The class 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
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:
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).
Since:
1.3
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 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
a and is equal to a mathematical integer.
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 positive 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.
The double value that is closer than any other to
e, the base of the natural logarithms.
PI
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.
Method Detail
sin
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 positive zero, then the result is
positive zero; if the argument is negative zero, then the
result is negative zero.
Parameters:
a - an angle, in radians.
Returns:
the sine of the argument.
cos
public static double cos(double a)
Returns the trigonometric cosine of an angle. Special case:
If the argument is NaN or an infinity, then the
result is NaN.
Parameters:
a - an angle, in radians.
Returns:
the cosine of the argument.
tan
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 positive zero, then the result is
positive zero; if the argument is negative zero, then the
result is negative zero
Parameters:
a - an angle, in radians.
Returns:
the tangent of the argument.
asin
public static double asin(double a)
Returns the arc sine of an angle, in the range of -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 positive zero, then the result is positive
zero; if the argument is negative zero, then the result is
negative zero.
Parameters:
a - the double value whose arc sine is to
be returned.
Returns:
the arc sine of the argument.
acos
public static double acos(double a)
Returns the arc cosine of an angle, in the range of 0.0 through
pi. Special case:
If the argument is NaN or its absolute value is greater
than 1, then the result is NaN.
Parameters:
a - the double value whose arc cosine is to
be returned.
Returns:
the arc cosine of the argument.
atan
public static double atan(double a)
Returns the arc tangent of an angle, in the range of -pi/2
through pi/2. Special cases:
If the argument is NaN, then the result is NaN.
If the argument is positive zero, then the result is positive
zero; if the argument is negative zero, then the result is
negative zero.
Parameters:
a - the double value whose arc tangent is to
be returned.
Returns:
the arc tangent of the argument.
toRadians
public static double toRadians(double angdeg)
Converts an angle measured in degrees to the equivalent angle
measured in radians.
Parameters:
angdeg - an angle, in degrees
Returns:
the measurement of the angle angdeg
in radians.
toDegrees
public static double toDegrees(double angrad)
Converts an angle measured in radians to the equivalent angle
measured in degrees.
Parameters:
angrad - an angle, in radians
Returns:
the measurement of the angle angrad
in degrees.
exp
public static double exp(double a)
Returns the exponential number e (i.e., 2.718...) 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.
Parameters:
a - a double value.
Returns:
the value e^{a}, where e is the base of
the natural logarithms.
log
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.
Parameters:
a - a number greater than 0.0.
Returns:
the value ln a, the natural logarithm of
a.
sqrt
public static double sqrt(double a)
Returns the 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 mathetmatical square root of the argument value.
Parameters:
a - a double value.
Returns:
the positive square root of a.
IEEEremainder
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 - the dividend.
f2 - the divisor.
Returns:
the remainder when f1 is divided by
f2.
ceil
public 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. 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 - a double value.
Returns:
the smallest (closest to negative infinity)
double value that is not less than the argument
and is equal to a mathematical integer.
floor
public 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. 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 - a double value.
Returns:
the largest (closest to positive infinity)
double value that is not greater than the argument
and is equal to a mathematical integer.
rint
public static double rint(double a)
Returns the double value that is closest in value to
a 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:
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 - a double value.
Returns:
the closest double value to a that is
equal to a mathematical integer.
atan2
public static double atan2(double a,
double b)
Converts rectangular coordinates (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. 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.
Parameters:
a - a double value.
b - a double value.
Returns:
the theta component of the point
(r, theta)
in polar coordinates that corresponds to the point
(b, a) in Cartesian coordinates.
pow
public static double pow(double a,
double b)
Returns of 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 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 floating-point value is
considered to be an integer if and only if it is a fixed point of the
method ceil or, which is the same thing, 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.)
Parameters:
a - a double value.
b - a double value.
Returns:
the value a^{b}.
round
public static int round(float a)
Returns the closest 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:
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 - a float value.
Returns:
the value of the argument rounded to the nearest
int value.
Returns the closest 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:
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 - a double value.
Returns:
the value of the argument rounded to the nearest
long value.
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.
Returns:
a pseudorandom double greater than or equal
to 0.0 and less than 1.0.
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.
Parameters:
a - the int argument whose absolute value is
to be determined.
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.
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.
In other words, the result is equal to the value of the expression:
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.
In other words, the result is equal to the value of the expression:
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.
Returns the greater of two long values. That is, the
result is the argument closer to the value of
Long.MAX_VALUE. If the argumens have the same value,
the result is that same value.
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 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 - a float value.
b - a float value.
Returns:
the larger of a and b.
max
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 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 - a double value.
b - a double value.
Returns:
the larger of a and b.
min
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.
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.
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
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 - a float value.
b - a float value.
Returns:
the smaller of a and b.
min
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
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.
Submit a bug or feature For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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