public class ThirdMoment extends SecondMoment implements java.io.Serializable
The following recursive updating formula is used:
Let
SecondMoment
new value = old value - 3 * (dev/n) * m2 + (n-1) * (n -2) * (dev^3/n^2)
Returns Double.NaN
if no data values have been added and
returns 0
if there is just one value in the data set.
Note that this implementation is not synchronized. If
multiple threads access an instance of this class concurrently, and at least
one of the threads invokes the increment()
or
clear()
method, it must be synchronized externally.
Modifier and Type | Field and Description |
---|---|
protected double |
m3
third moment of values that have been added
|
protected double |
nDevSq
Square of deviation of most recently added value from previous first
moment, normalized by previous sample size.
|
m2
dev, m1, n, nDev
Constructor and Description |
---|
ThirdMoment()
Create a FourthMoment instance
|
ThirdMoment(ThirdMoment original)
Copy constructor, creates a new
ThirdMoment identical
to the original |
Modifier and Type | Method and Description |
---|---|
void |
clear()
Clears the internal state of the Statistic
|
ThirdMoment |
copy()
Returns a copy of the statistic with the same internal state.
|
static void |
copy(ThirdMoment source,
ThirdMoment dest)
Copies source to dest.
|
double |
getResult()
Returns the current value of the Statistic.
|
void |
increment(double d)
Updates the internal state of the statistic to reflect the addition of the new value.
|
copy
copy, getN
equals, evaluate, evaluate, hashCode, incrementAll, incrementAll
test, test
protected double m3
protected double nDevSq
public ThirdMoment()
public ThirdMoment(ThirdMoment original)
ThirdMoment
identical
to the original
original
- the ThirdMoment
instance to copypublic void increment(double d)
increment
in interface StorelessUnivariateStatistic
increment
in class SecondMoment
d
- the new value.public double getResult()
getResult
in interface StorelessUnivariateStatistic
getResult
in class SecondMoment
Double.NaN
if it
has been cleared or just instantiated.public void clear()
clear
in interface StorelessUnivariateStatistic
clear
in class SecondMoment
public ThirdMoment copy()
copy
in interface StorelessUnivariateStatistic
copy
in interface UnivariateStatistic
copy
in class SecondMoment
public static void copy(ThirdMoment source, ThirdMoment dest)
Neither source nor dest can be null.
source
- ThirdMoment to copydest
- ThirdMoment to copy tojava.lang.NullPointerException
- if either source or dest is null