Class SumOfSquares
- java.lang.Object
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- org.apache.commons.statistics.descriptive.SumOfSquares
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- All Implemented Interfaces:
DoubleConsumer,DoubleSupplier,IntSupplier,LongSupplier,DoubleStatistic,StatisticAccumulator<SumOfSquares>,StatisticResult
public final class SumOfSquares extends Object implements DoubleStatistic, StatisticAccumulator<SumOfSquares>
Returns the sum of the squares of the available values. Uses the following definition:\[ \sum_{i=1}^n x_i^2 \]
where \( n \) is the number of samples.
- The result is zero if no values are observed.
- The result is
NaNif any of the values isNaN. - The result is
+infinityif any of the values isinfinity, or the sum overflows.
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
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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.SumOfSquarescombine(SumOfSquares other)Combines the state of theotherstatistic into this one.static SumOfSquarescreate()Creates an instance.doublegetAsDouble()Gets the sum of squares of all input values.static SumOfSquaresof(double... 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 SumOfSquares create()
Creates an instance.The initial result is zero.
- Returns:
SumOfSquaresinstance.
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of
public static SumOfSquares of(double... values)
Returns an instance populated using the inputvalues.The result is
NaNif any of the values isNaNor the product at any point is aNaN.When the input is an empty array, the result is zero.
- Parameters:
values- Values.- Returns:
SumOfSquaresinstance.
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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 sum of squares of all input values.When no values have been added, the result is zero.
- Specified by:
getAsDoublein interfaceDoubleSupplier- Returns:
- sum of squares of all values.
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combine
public SumOfSquares combine(SumOfSquares other)
Description copied from interface:StatisticAccumulatorCombines the state of theotherstatistic into this one.- Specified by:
combinein interfaceStatisticAccumulator<SumOfSquares>- Parameters:
other- Another statistic to be combined.- Returns:
thisinstance after combiningother.
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