public class GeometricMean extends AbstractStorelessUnivariateStatistic implements java.io.Serializable
Uses a SumOfLogs instance to compute sum of logs and returns
exp( 1/n (sum of logs) ). Therefore,
NaN.Double.POSITIVE_INFINITY, but at least one value is 0, the
result is 0.Double.POSITIVE_INFINITY and
Double.NEGATIVE_INFINITY are among the values, the result is
NaN.
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.
| Constructor and Description |
|---|
GeometricMean()
Create a GeometricMean instance
|
GeometricMean(GeometricMean original)
Copy constructor, creates a new
GeometricMean identical
to the original |
GeometricMean(SumOfLogs sumOfLogs)
Create a GeometricMean instance using the given SumOfLogs instance
|
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Clears the internal state of the Statistic
|
GeometricMean |
copy()
Returns a copy of the statistic with the same internal state.
|
static void |
copy(GeometricMean source,
GeometricMean dest)
Copies source to dest.
|
double |
evaluate(double[] values,
int begin,
int length)
Returns the geometric mean of the entries in the specified portion
of the input array.
|
long |
getN()
Returns the number of values that have been added.
|
double |
getResult()
Returns the current value of the Statistic.
|
StorelessUnivariateStatistic |
getSumLogImpl()
Returns the currently configured sum of logs implementation
|
void |
increment(double d)
Updates the internal state of the statistic to reflect the addition of the new value.
|
void |
setSumLogImpl(StorelessUnivariateStatistic sumLogImpl)
Sets the implementation for the sum of logs.
|
equals, evaluate, hashCode, incrementAll, incrementAlltest, testpublic GeometricMean()
public GeometricMean(GeometricMean original)
GeometricMean identical
to the originaloriginal - the GeometricMean instance to copypublic GeometricMean(SumOfLogs sumOfLogs)
sumOfLogs - sum of logs instance to use for computationpublic GeometricMean copy()
copy in interface StorelessUnivariateStatisticcopy in interface UnivariateStatisticcopy in class AbstractStorelessUnivariateStatisticpublic void increment(double d)
increment in interface StorelessUnivariateStatisticincrement in class AbstractStorelessUnivariateStatisticd - the new value.public double getResult()
getResult in interface StorelessUnivariateStatisticgetResult in class AbstractStorelessUnivariateStatisticDouble.NaN if it
has been cleared or just instantiated.public void clear()
clear in interface StorelessUnivariateStatisticclear in class AbstractStorelessUnivariateStatisticpublic double evaluate(double[] values,
int begin,
int length)
See GeometricMean for details on the computing algorithm.
Throws IllegalArgumentException if the array is null.
evaluate in interface UnivariateStatisticevaluate in class AbstractStorelessUnivariateStatisticvalues - input array containing the valuesbegin - first array element to includelength - the number of elements to includejava.lang.IllegalArgumentException - if the input array is null or the array
index parameters are not validUnivariateStatistic.evaluate(double[], int, int)public long getN()
getN in interface StorelessUnivariateStatisticpublic void setSumLogImpl(StorelessUnivariateStatistic sumLogImpl)
Sets the implementation for the sum of logs.
This method must be activated before any data has been added - i.e.,
before increment has been used to add data;
otherwise an IllegalStateException will be thrown.
sumLogImpl - the StorelessUnivariateStatistic instance to use
for computing the log sumjava.lang.IllegalStateException - if data has already been added
(i.e if n > 0)public StorelessUnivariateStatistic getSumLogImpl()
public static void copy(GeometricMean source, GeometricMean dest)
Neither source nor dest can be null.
source - GeometricMean to copydest - GeometricMean to copy tojava.lang.NullPointerException - if either source or dest is null