@GwtCompatible(emulated=true) public final class DoubleMath extends Object
Math
.Modifier and Type | Method and Description |
---|---|
static double |
factorial(int n)
Returns
n! , that is, the product of the first n positive integers, 1 if
n == 0 , or n! , or Double.POSITIVE_INFINITY if n! >
Double.MAX_VALUE . |
static int |
fuzzyCompare(double a,
double b,
double tolerance)
Compares
a and b "fuzzily," with a tolerance for nearly-equal values. |
static boolean |
fuzzyEquals(double a,
double b,
double tolerance)
Returns
true if a and b are within tolerance of each other. |
static boolean |
isMathematicalInteger(double x)
Returns
true if x represents a mathematical integer. |
static boolean |
isPowerOfTwo(double x)
Returns
true if x is exactly equal to 2^k for some finite integer
k . |
static double |
log2(double x)
Returns the base 2 logarithm of a double value.
|
static int |
log2(double x,
RoundingMode mode)
Returns the base 2 logarithm of a double value, rounded with the specified rounding mode to an
int . |
static double |
mean(double... values)
Deprecated.
Use
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>) instead, noting the less strict handling of non-finite
values. |
static double |
mean(int... values)
Deprecated.
Use
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>) instead, noting the less strict handling of non-finite
values. |
static double |
mean(Iterable<? extends Number> values)
Deprecated.
Use
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>) instead, noting the less strict handling of non-finite
values. |
static double |
mean(Iterator<? extends Number> values)
Deprecated.
Use
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>) instead, noting the less strict handling of non-finite
values. |
static double |
mean(long... values)
Deprecated.
Use
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>) instead, noting the less strict handling of non-finite
values. |
static BigInteger |
roundToBigInteger(double x,
RoundingMode mode)
Returns the
BigInteger value that is equal to x rounded with the specified
rounding mode, if possible. |
static int |
roundToInt(double x,
RoundingMode mode)
Returns the
int value that is equal to x rounded with the specified rounding
mode, if possible. |
static long |
roundToLong(double x,
RoundingMode mode)
Returns the
long value that is equal to x rounded with the specified rounding
mode, if possible. |
@GwtIncompatible public static int roundToInt(double x, RoundingMode mode)
int
value that is equal to x
rounded with the specified rounding
mode, if possible.ArithmeticException
- if
x
is infinite or NaN
x
, after being rounded to a mathematical integer using the specified rounding
mode, is either less than Integer.MIN_VALUE
or greater than Integer.MAX_VALUE
x
is not a mathematical integer and mode
is RoundingMode.UNNECESSARY
@GwtIncompatible public static long roundToLong(double x, RoundingMode mode)
long
value that is equal to x
rounded with the specified rounding
mode, if possible.ArithmeticException
- if
x
is infinite or NaN
x
, after being rounded to a mathematical integer using the specified rounding
mode, is either less than Long.MIN_VALUE
or greater than Long.MAX_VALUE
x
is not a mathematical integer and mode
is RoundingMode.UNNECESSARY
@GwtIncompatible public static BigInteger roundToBigInteger(double x, RoundingMode mode)
BigInteger
value that is equal to x
rounded with the specified
rounding mode, if possible.ArithmeticException
- if
x
is infinite or NaN
x
is not a mathematical integer and mode
is RoundingMode.UNNECESSARY
@GwtIncompatible public static boolean isPowerOfTwo(double x)
true
if x
is exactly equal to 2^k
for some finite integer
k
.public static double log2(double x)
Special cases:
x
is NaN or less than zero, the result is NaN.
x
is positive infinity, the result is positive infinity.
x
is positive or negative zero, the result is negative infinity.
The computed result is within 1 ulp of the exact result.
If the result of this method will be immediately rounded to an int
, log2(double, RoundingMode)
is faster.
@GwtIncompatible public static int log2(double x, RoundingMode mode)
int
.
Regardless of the rounding mode, this is faster than (int) log2(x)
.
IllegalArgumentException
- if x <= 0.0
, x
is NaN, or x
is
infinite@GwtIncompatible public static boolean isMathematicalInteger(double x)
true
if x
represents a mathematical integer.
This is equivalent to, but not necessarily implemented as, the expression !Double.isNaN(x) && !Double.isInfinite(x) && x == Math.rint(x)
.
public static double factorial(int n)
n!
, that is, the product of the first n
positive integers, 1
if
n == 0
, or n!
, or Double.POSITIVE_INFINITY
if n! >
Double.MAX_VALUE
.
The result is within 1 ulp of the true value.
IllegalArgumentException
- if n < 0
public static boolean fuzzyEquals(double a, double b, double tolerance)
true
if a
and b
are within tolerance
of each other.
Technically speaking, this is equivalent to Math.abs(a - b) <= tolerance ||
Double.valueOf(a).equals(Double.valueOf(b))
.
Notable special cases include:
a == b
, then a
and b
are always fuzzily equal.
tolerance
is zero, and neither a
nor b
is NaN, then a
and b
are fuzzily equal if and only if a == b
.
Double.POSITIVE_INFINITY
tolerance, all non-NaN values are fuzzily equal.
Double.POSITIVE_INFINITY
and Double.NEGATIVE_INFINITY
are fuzzily equal only to themselves.
This is reflexive and symmetric, but not transitive, so it is not an
equivalence relation and not suitable for use in Object.equals(java.lang.Object)
implementations.
IllegalArgumentException
- if tolerance
is < 0
or NaNpublic static int fuzzyCompare(double a, double b, double tolerance)
a
and b
"fuzzily," with a tolerance for nearly-equal values.
This method is equivalent to fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a,
b)
. In particular, like Double.compare(double, double)
, it treats all NaN values as
equal and greater than all other values (including Double.POSITIVE_INFINITY
).
This is not a total ordering and is not suitable for use in Comparable.compareTo(T)
implementations. In particular, it is not transitive.
IllegalArgumentException
- if tolerance
is < 0
or NaN@Deprecated @GwtIncompatible public static double mean(double... values)
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite
values.values
.
If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
values
- a nonempty series of valuesIllegalArgumentException
- if values
is empty or contains any non-finite value@Deprecated public static double mean(int... values)
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite
values.values
.
If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
values
- a nonempty series of valuesIllegalArgumentException
- if values
is empty@Deprecated public static double mean(long... values)
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite
values.values
.
If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
values
- a nonempty series of values, which will be converted to double
values
(this may cause loss of precision for longs of magnitude over 2^53 (slightly over 9e15))IllegalArgumentException
- if values
is empty@Deprecated @GwtIncompatible public static double mean(Iterable<? extends Number> values)
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite
values.values
.
If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
values
- a nonempty series of values, which will be converted to double
values
(this may cause loss of precision)IllegalArgumentException
- if values
is empty or contains any non-finite value@Deprecated @GwtIncompatible public static double mean(Iterator<? extends Number> values)
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite
values.values
.
If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
values
- a nonempty series of values, which will be converted to double
values
(this may cause loss of precision)IllegalArgumentException
- if values
is empty or contains any non-finite valueCopyright © 2010–2019. All rights reserved.