Class LongSumOfSquares
- java.lang.Object
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- org.apache.commons.statistics.descriptive.LongSumOfSquares
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- All Implemented Interfaces:
DoubleSupplier,IntSupplier,LongConsumer,LongSupplier,LongStatistic,StatisticAccumulator<LongSumOfSquares>,StatisticResult
public final class LongSumOfSquares extends Object implements LongStatistic, StatisticAccumulator<LongSumOfSquares>
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 implementation uses an exact integer sum to compute the sum of squared values. The exact sum is returned using
getAsBigInteger(). Methods that returnintorlongprimitives will raise an exception if the result overflows.Note that the implementation does not use
BigIntegerarithmetic; for performance the sum is computed using primitives to create an unsigned 192-bit integer. Support is provided for at least 263 observations.This class is designed to work with (though does not require) streams.
This implementation 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 implementation 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(long value)Updates the state of the statistic to reflect the addition ofvalue.LongSumOfSquarescombine(LongSumOfSquares other)Combines the state of theotherstatistic into this one.static LongSumOfSquarescreate()Creates an instance.BigIntegergetAsBigInteger()Gets the sum of squares of all input values.doublegetAsDouble()Gets the sum of squares of all input values.intgetAsInt()Gets the sum of squares of all input values.longgetAsLong()Gets the sum of squares of all input values.static LongSumOfSquaresof(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.LongConsumer
andThen
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Method Detail
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create
public static LongSumOfSquares create()
Creates an instance.The initial result is zero.
- Returns:
LongSumOfSquaresinstance.
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of
public static LongSumOfSquares of(long... values)
Returns an instance populated using the inputvalues.- Parameters:
values- Values.- Returns:
LongSumOfSquaresinstance.
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accept
public void accept(long value)
Updates the state of the statistic to reflect the addition ofvalue.- Specified by:
acceptin interfaceLongConsumer- Parameters:
value- Value.
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getAsInt
public int getAsInt()
Gets the sum of squares of all input values.When no values have been added, the result is zero.
Warning: This will raise an
ArithmeticExceptionif the result is not within the range[0, 2^31).- Specified by:
getAsIntin interfaceIntSupplier- Specified by:
getAsIntin interfaceStatisticResult- Returns:
- sum of all values.
- Throws:
ArithmeticException- if theresultoverflows anint- See Also:
getAsBigInteger()
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getAsLong
public long getAsLong()
Gets the sum of squares of all input values.When no values have been added, the result is zero.
Warning: This will raise an
ArithmeticExceptionif the result is not within the range[0, 2^63).- Specified by:
getAsLongin interfaceLongSupplier- Specified by:
getAsLongin interfaceStatisticResult- Returns:
- sum of all values.
- Throws:
ArithmeticException- if theresultoverflows along- See Also:
getAsBigInteger()
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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.
Note that this conversion can lose information about the precision of the
BigIntegervalue.- Specified by:
getAsDoublein interfaceDoubleSupplier- Returns:
- sum of squares of all values.
- See Also:
getAsBigInteger()
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getAsBigInteger
public BigInteger getAsBigInteger()
Gets the sum of squares of all input values.When no values have been added, the result is zero.
- Specified by:
getAsBigIntegerin interfaceStatisticResult- Returns:
- sum of squares of all values.
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combine
public LongSumOfSquares combine(LongSumOfSquares other)
Description copied from interface:StatisticAccumulatorCombines the state of theotherstatistic into this one.- Specified by:
combinein interfaceStatisticAccumulator<LongSumOfSquares>- Parameters:
other- Another statistic to be combined.- Returns:
thisinstance after combiningother.
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