Class GeometricMean
- java.lang.Object
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- org.apache.commons.statistics.descriptive.GeometricMean
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- All Implemented Interfaces:
DoubleConsumer,DoubleSupplier,IntSupplier,LongSupplier,DoubleStatistic,StatisticAccumulator<GeometricMean>,StatisticResult
public final class GeometricMean extends Object implements DoubleStatistic, StatisticAccumulator<GeometricMean>
Computes the geometric mean of the available values. Uses the following definition of the geometric mean:\[ \left(\prod_{i=1}^n x_i\right)^\frac{1}{n} \]
where \( n \) is the number of samples. This implementation uses the log scale:
\[ \exp{\left( {\frac{1}{n}\sum_{i=1}^n \ln x_i} \right)} \]
- The result is
NaNif no values are added. - The result is
NaNif any of the values isNaN. - The result is
NaNif any of the values is negative. - The result is
+infinityif all values are in the range(0, +infinity]and at least one value is+infinity. - The result is
0if all values are in the range[0, +infinity)and at least one value is zero. - The result is
NaNif all values are in the range[0, +infinity]and at least one value is zero, and one value is+infinity.
Supports up to 263 (exclusive) observations. This implementation does not check for overflow of the count.
This class is designed to work with (though does not require) streams.
This instance is not thread safe. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the
acceptorcombinemethod, it must be synchronized externally.However, it is safe to use
acceptandcombineasaccumulatorandcombinerfunctions ofCollectoron a parallel stream, because the parallel instance ofStream.collect()provides the necessary partitioning, isolation, and merging of results for safe and efficient parallel execution.- Since:
- 1.1
- See Also:
- Geometric mean (Wikipedia),
SumOfLogs
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidaccept(double value)Updates the state of the statistic to reflect the addition ofvalue.GeometricMeancombine(GeometricMean other)Combines the state of theotherstatistic into this one.static GeometricMeancreate()Creates an instance.doublegetAsDouble()Gets the geometric mean of all input values.static GeometricMeanof(double... values)Returns an instance populated using the inputvalues.static GeometricMeanof(int... values)Returns an instance populated using the inputvalues.static GeometricMeanof(long... values)Returns an instance populated using the inputvalues.-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.function.DoubleConsumer
andThen
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Methods inherited from interface org.apache.commons.statistics.descriptive.StatisticResult
getAsBigInteger, getAsInt, getAsLong
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Method Detail
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create
public static GeometricMean create()
Creates an instance.The initial result is
NaN.- Returns:
GeometricMeaninstance.
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of
public static GeometricMean of(double... values)
Returns an instance populated using the inputvalues.When the input is an empty array, the result is
NaN.- Parameters:
values- Values.- Returns:
GeometricMeaninstance.
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of
public static GeometricMean of(int... values)
Returns an instance populated using the inputvalues.When the input is an empty array, the result is
NaN.- Parameters:
values- Values.- Returns:
GeometricMeaninstance.
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of
public static GeometricMean of(long... values)
Returns an instance populated using the inputvalues.When the input is an empty array, the result is
NaN.- Parameters:
values- Values.- Returns:
GeometricMeaninstance.
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accept
public void accept(double value)
Updates the state of the statistic to reflect the addition ofvalue.- Specified by:
acceptin interfaceDoubleConsumer- Parameters:
value- Value.
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getAsDouble
public double getAsDouble()
Gets the geometric mean of all input values.When no values have been added, the result is
NaN.- Specified by:
getAsDoublein interfaceDoubleSupplier- Returns:
- geometric mean of all values.
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combine
public GeometricMean combine(GeometricMean other)
Description copied from interface:StatisticAccumulatorCombines the state of theotherstatistic into this one.- Specified by:
combinein interfaceStatisticAccumulator<GeometricMean>- Parameters:
other- Another statistic to be combined.- Returns:
thisinstance after combiningother.
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