Class GeometricMean
java.lang.Object
org.hipparchus.stat.descriptive.AbstractStorelessUnivariateStatistic
org.hipparchus.stat.descriptive.moment.GeometricMean
- All Implemented Interfaces:
Serializable
,DoubleConsumer
,AggregatableStatistic<GeometricMean>
,StorelessUnivariateStatistic
,UnivariateStatistic
,MathArrays.Function
public class GeometricMean
extends AbstractStorelessUnivariateStatistic
implements AggregatableStatistic<GeometricMean>, Serializable
Returns the
geometric mean of the available values.
Uses a SumOfLogs
instance to compute sum of logs and returns
exp( 1/n (sum of logs) ).
Therefore,
- If any of values are < 0, the result is
NaN.
- If all values are non-negative and less than
Double.POSITIVE_INFINITY
, but at least one value is 0, the result is0.
- If both
Double.POSITIVE_INFINITY
andDouble.NEGATIVE_INFINITY
are among the values, the result isNaN.
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.
- See Also:
-
Constructor Summary
ConstructorDescriptionCreate a GeometricMean instance.GeometricMean
(GeometricMean original) Copy constructor, creates a newGeometricMean
identical to theoriginal
.GeometricMean
(SumOfLogs sumOfLogs) Create a GeometricMean instance using the given SumOfLogs instance. -
Method Summary
Modifier and TypeMethodDescriptionvoid
aggregate
(GeometricMean other) Aggregates the provided instance into this instance.void
clear()
Clears the internal state of the Statisticcopy()
Returns a copy of the statistic with the same internal state.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
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.Methods inherited from class org.hipparchus.stat.descriptive.AbstractStorelessUnivariateStatistic
equals, hashCode, toString
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.hipparchus.stat.descriptive.AggregatableStatistic
aggregate, aggregate
Methods inherited from interface java.util.function.DoubleConsumer
andThen
Methods inherited from interface org.hipparchus.stat.descriptive.StorelessUnivariateStatistic
accept, incrementAll, incrementAll
Methods inherited from interface org.hipparchus.stat.descriptive.UnivariateStatistic
evaluate
-
Constructor Details
-
GeometricMean
public GeometricMean()Create a GeometricMean instance. -
GeometricMean
Create a GeometricMean instance using the given SumOfLogs instance.- Parameters:
sumOfLogs
- sum of logs instance to use for computation.
-
GeometricMean
Copy constructor, creates a newGeometricMean
identical to theoriginal
.- Parameters:
original
- theGeometricMean
instance to copy- Throws:
NullArgumentException
- if original is null
-
-
Method Details
-
copy
Returns a copy of the statistic with the same internal state.- Specified by:
copy
in interfaceStorelessUnivariateStatistic
- Specified by:
copy
in interfaceUnivariateStatistic
- Specified by:
copy
in classAbstractStorelessUnivariateStatistic
- Returns:
- a copy of the statistic
-
increment
public void increment(double d) Updates the internal state of the statistic to reflect the addition of the new value.- Specified by:
increment
in interfaceStorelessUnivariateStatistic
- Specified by:
increment
in classAbstractStorelessUnivariateStatistic
- Parameters:
d
- the new value.
-
getResult
public double getResult()Returns the current value of the Statistic.- Specified by:
getResult
in interfaceStorelessUnivariateStatistic
- Specified by:
getResult
in classAbstractStorelessUnivariateStatistic
- Returns:
- value of the statistic,
Double.NaN
if it has been cleared or just instantiated.
-
clear
public void clear()Clears the internal state of the Statistic- Specified by:
clear
in interfaceStorelessUnivariateStatistic
- Specified by:
clear
in classAbstractStorelessUnivariateStatistic
-
aggregate
Aggregates the provided instance into this instance.This method can be used to combine statistics computed over partitions or subsamples - i.e., the value of this instance after this operation should be the same as if a single statistic would have been applied over the combined dataset.
- Specified by:
aggregate
in interfaceAggregatableStatistic<GeometricMean>
- Parameters:
other
- the instance to aggregate into this instance
-
evaluate
Returns the geometric mean of the entries in the specified portion of the input array.See
GeometricMean
for details on the computing algorithm.- Specified by:
evaluate
in interfaceMathArrays.Function
- Specified by:
evaluate
in interfaceStorelessUnivariateStatistic
- Specified by:
evaluate
in interfaceUnivariateStatistic
- Parameters:
values
- input array containing the valuesbegin
- first array element to includelength
- the number of elements to include- Returns:
- the geometric mean or Double.NaN if length = 0 or any of the values are <= 0.
- Throws:
MathIllegalArgumentException
- if the input array is null or the array index parameters are not valid- See Also:
-
getN
public long getN()Returns the number of values that have been added.- Specified by:
getN
in interfaceStorelessUnivariateStatistic
- Returns:
- the number of values.
-