Class GeometricMean
- All Implemented Interfaces:
DoubleConsumer
,DoubleSupplier
,IntSupplier
,LongSupplier
,DoubleStatistic
,StatisticAccumulator<GeometricMean>
,StatisticResult
\[ \left(\prod_{i=1}^n x_i\right)^\frac{1}{n} \]
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
NaN
if no values are added. - The result is
NaN
if any of the values isNaN
. - The result is
NaN
if any of the values is negative. - The result is
+infinity
if all values are in the range(0, +infinity]
and at least one value is+infinity
. - The result is
0
if all values are in the range[0, +infinity)
and at least one value is zero. - The result is
NaN
if 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 accept
or
combine
method, it must be synchronized externally.
However, it is safe to use accept
and combine
as accumulator
and combiner
functions of
Collector
on a parallel stream,
because the parallel instance of Stream.collect()
provides the necessary partitioning, isolation, and merging of results for
safe and efficient parallel execution.
- Since:
- 1.1
- See Also:
-
Field Summary
Fields -
Constructor Summary
ConstructorsModifierConstructorDescriptionprivate
Create an instance.private
GeometricMean
(SumOfLogs sumOfLogs, long n) Create an instance. -
Method Summary
Modifier and TypeMethodDescriptionvoid
accept
(double value) Updates the state of the statistic to reflect the addition ofvalue
.combine
(GeometricMean other) Combines the state of theother
statistic into this one.(package private) static double
computeGeometricMean
(long n, SumOfLogs sumOfLogs) Compute the geometric mean.static GeometricMean
create()
Creates an instance.double
Gets the geometric mean of all input values.static GeometricMean
of
(double... values) Returns an instance populated using the inputvalues
.static GeometricMean
of
(int... values) Returns an instance populated using the inputvalues
.static GeometricMean
of
(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
Methods inherited from interface java.util.function.DoubleConsumer
andThen
Methods inherited from interface org.apache.commons.statistics.descriptive.StatisticResult
getAsBigInteger, getAsInt, getAsLong
-
Field Details
-
n
private long nCount of values that have been added. -
sumOfLogs
Sum of logs used to compute the geometric mean.
-
-
Constructor Details
-
GeometricMean
private GeometricMean()Create an instance. -
GeometricMean
Create an instance.- Parameters:
sumOfLogs
- Sum of logs.n
- Count of values.
-
-
Method Details
-
create
Creates an instance.The initial result is
NaN
.- Returns:
GeometricMean
instance.
-
of
Returns an instance populated using the inputvalues
.When the input is an empty array, the result is
NaN
.- Parameters:
values
- Values.- Returns:
GeometricMean
instance.
-
of
Returns an instance populated using the inputvalues
.When the input is an empty array, the result is
NaN
.- Parameters:
values
- Values.- Returns:
GeometricMean
instance.
-
of
Returns an instance populated using the inputvalues
.When the input is an empty array, the result is
NaN
.- Parameters:
values
- Values.- Returns:
GeometricMean
instance.
-
accept
public void accept(double value) Updates the state of the statistic to reflect the addition ofvalue
.- Specified by:
accept
in interfaceDoubleConsumer
- Parameters:
value
- Value.
-
getAsDouble
public double getAsDouble()Gets the geometric mean of all input values.When no values have been added, the result is
NaN
.- Specified by:
getAsDouble
in interfaceDoubleSupplier
- Returns:
- geometric mean of all values.
-
combine
Description copied from interface:StatisticAccumulator
Combines the state of theother
statistic into this one.- Specified by:
combine
in interfaceStatisticAccumulator<GeometricMean>
- Parameters:
other
- Another statistic to be combined.- Returns:
this
instance after combiningother
.
-
computeGeometricMean
Compute the geometric mean.- Parameters:
n
- Count of values.sumOfLogs
- Sum of logs.- Returns:
- the geometric mean
-