Class DoubleMath
Math
.- Since:
- 11.0
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Field Summary
FieldsModifier and TypeFieldDescription(package private) static final double[]
private static final double
(package private) static final int
private static final double
private static final double
private static final double
private static final double
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate static double
checkFinite
(double argument) static double
factorial
(int n) Returnsn!
, that is, the product of the firstn
positive integers,1
ifn == 0
, orn!
, orDouble.POSITIVE_INFINITY
ifn! > Double.MAX_VALUE
.static int
fuzzyCompare
(double a, double b, double tolerance) Comparesa
andb
"fuzzily," with a tolerance for nearly-equal values.static boolean
fuzzyEquals
(double a, double b, double tolerance) Returnstrue
ifa
andb
are withintolerance
of each other.static boolean
isMathematicalInteger
(double x) Returnstrue
ifx
represents a mathematical integer.static boolean
isPowerOfTwo
(double x) Returnstrue
ifx
is exactly equal to2^k
for some finite integerk
.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 anint
.static double
mean
(double... values) Deprecated.static double
mean
(int... values) Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.static double
mean
(long... values) Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.static double
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.static double
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.(package private) static double
roundIntermediate
(double x, RoundingMode mode) static BigInteger
roundToBigInteger
(double x, RoundingMode mode) Returns theBigInteger
value that is equal tox
rounded with the specified rounding mode, if possible.static int
roundToInt
(double x, RoundingMode mode) Returns theint
value that is equal tox
rounded with the specified rounding mode, if possible.static long
roundToLong
(double x, RoundingMode mode) Returns thelong
value that is equal tox
rounded with the specified rounding mode, if possible.
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Field Details
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MIN_INT_AS_DOUBLE
private static final double MIN_INT_AS_DOUBLE- See Also:
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MAX_INT_AS_DOUBLE
private static final double MAX_INT_AS_DOUBLE- See Also:
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MIN_LONG_AS_DOUBLE
private static final double MIN_LONG_AS_DOUBLE- See Also:
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MAX_LONG_AS_DOUBLE_PLUS_ONE
private static final double MAX_LONG_AS_DOUBLE_PLUS_ONE- See Also:
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LN_2
private static final double LN_2 -
MAX_FACTORIAL
static final int MAX_FACTORIAL- See Also:
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everySixteenthFactorial
static final double[] everySixteenthFactorial
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Constructor Details
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DoubleMath
private DoubleMath()
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Method Details
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roundIntermediate
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roundToInt
Returns theint
value that is equal tox
rounded with the specified rounding mode, if possible.- Throws:
ArithmeticException
- ifx
is infinite or NaNx
, after being rounded to a mathematical integer using the specified rounding mode, is either less thanInteger.MIN_VALUE
or greater thanInteger.MAX_VALUE
x
is not a mathematical integer andmode
isRoundingMode.UNNECESSARY
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roundToLong
Returns thelong
value that is equal tox
rounded with the specified rounding mode, if possible.- Throws:
ArithmeticException
- ifx
is infinite or NaNx
, after being rounded to a mathematical integer using the specified rounding mode, is either less thanLong.MIN_VALUE
or greater thanLong.MAX_VALUE
x
is not a mathematical integer andmode
isRoundingMode.UNNECESSARY
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roundToBigInteger
Returns theBigInteger
value that is equal tox
rounded with the specified rounding mode, if possible.- Throws:
ArithmeticException
- ifx
is infinite or NaNx
is not a mathematical integer andmode
isRoundingMode.UNNECESSARY
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isPowerOfTwo
public static boolean isPowerOfTwo(double x) Returnstrue
ifx
is exactly equal to2^k
for some finite integerk
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log2
public static double log2(double x) Returns the base 2 logarithm of a double value.Special cases:
- If
x
is NaN or less than zero, the result is NaN. - If
x
is positive infinity, the result is positive infinity. - If
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. - If
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log2
Returns the base 2 logarithm of a double value, rounded with the specified rounding mode to anint
.Regardless of the rounding mode, this is faster than
(int) log2(x)
.- Throws:
IllegalArgumentException
- ifx <= 0.0
,x
is NaN, orx
is infinite
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isMathematicalInteger
public static boolean isMathematicalInteger(double x) Returnstrue
ifx
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)
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factorial
public static double factorial(int n) Returnsn!
, that is, the product of the firstn
positive integers,1
ifn == 0
, orn!
, orDouble.POSITIVE_INFINITY
ifn! > Double.MAX_VALUE
.The result is within 1 ulp of the true value.
- Throws:
IllegalArgumentException
- ifn < 0
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fuzzyEquals
public static boolean fuzzyEquals(double a, double b, double tolerance) Returnstrue
ifa
andb
are withintolerance
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:
- All NaNs are fuzzily equal.
- If
a == b
, thena
andb
are always fuzzily equal. - Positive and negative zero are always fuzzily equal.
- If
tolerance
is zero, and neithera
norb
is NaN, thena
andb
are fuzzily equal if and only ifa == b
. - With
Double.POSITIVE_INFINITY
tolerance, all non-NaN values are fuzzily equal. - With finite tolerance,
Double.POSITIVE_INFINITY
andDouble.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.- Throws:
IllegalArgumentException
- iftolerance
is< 0
or NaN- Since:
- 13.0
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fuzzyCompare
public static int fuzzyCompare(double a, double b, double tolerance) Comparesa
andb
"fuzzily," with a tolerance for nearly-equal values.This method is equivalent to
fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a, b)
. In particular, likeDouble.compare(double, double)
, it treats all NaN values as equal and greater than all other values (includingDouble.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.- Throws:
IllegalArgumentException
- iftolerance
is< 0
or NaN- Since:
- 13.0
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mean
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.Returns the arithmetic mean ofvalues
.If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
- Parameters:
values
- a nonempty series of values- Throws:
IllegalArgumentException
- ifvalues
is empty or contains any non-finite value
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mean
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.Returns the arithmetic mean ofvalues
.If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
- Parameters:
values
- a nonempty series of values- Throws:
IllegalArgumentException
- ifvalues
is empty
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mean
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.Returns the arithmetic mean ofvalues
.If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
- Parameters:
values
- a nonempty series of values, which will be converted todouble
values (this may cause loss of precision for longs of magnitude over 2^53 (slightly over 9e15))- Throws:
IllegalArgumentException
- ifvalues
is empty
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mean
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.Returns the arithmetic mean ofvalues
.If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
- Parameters:
values
- a nonempty series of values, which will be converted todouble
values (this may cause loss of precision)- Throws:
IllegalArgumentException
- ifvalues
is empty or contains any non-finite value
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mean
Deprecated.UseStats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.Returns the arithmetic mean ofvalues
.If these values are a sample drawn from a population, this is also an unbiased estimator of the arithmetic mean of the population.
- Parameters:
values
- a nonempty series of values, which will be converted todouble
values (this may cause loss of precision)- Throws:
IllegalArgumentException
- ifvalues
is empty or contains any non-finite value
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checkFinite
private static double checkFinite(double argument)
-
Stats.meanOf(java.lang.Iterable<? extends java.lang.Number>)
instead, noting the less strict handling of non-finite values.