Class Median

java.lang.Object

org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic

org.apache.commons.math3.stat.descriptive.rank.Percentile

org.apache.commons.math3.stat.descriptive.rank.Median

All Implemented Interfaces:

Serializable, UnivariateStatistic, MathArrays.Function

public class Median
extends Percentile
implements Serializable

Returns the median of the available values. This is the same as the 50th percentile. See Percentile for a description of the algorithm used.

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:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class Percentile

Percentile.EstimationType

Field Summary

Fields

Modifier and Type	Field	Description
private static final double	FIXED_QUANTILE_50	Fixed quantile.
private static final long	serialVersionUID	Serializable version identifier

Constructor Summary

Constructors

Modifier	Constructor	Description
	Median()	Default constructor.
	Median(Median original)	Copy constructor, creates a new Median identical to the original
private	Median(Percentile.EstimationType estimationType, NaNStrategy nanStrategy, KthSelector kthSelector)	Constructs a Median with the specific Percentile.EstimationType, NaNStrategy and invalid reference PivotingStrategy .

Method Summary

Modifier and Type	Method	Description
Median	withEstimationType(Percentile.EstimationType newEstimationType)	Build a new instance similar to the current one except for the estimation type.
Median	withKthSelector(KthSelector newKthSelector)	Build a new instance similar to the current one except for the kthSelector instance specifically set.
Median	withNaNStrategy(NaNStrategy newNaNStrategy)	Build a new instance similar to the current one except for the NaN handling strategy.

Methods inherited from class Percentile

copy, copy, evaluate, evaluate, evaluate, evaluate, getEstimationType, getKthSelector, getNaNStrategy, getPivotingStrategy, getQuantile, getWorkArray, medianOf3, setData, setData, setQuantile

Methods inherited from class AbstractUnivariateStatistic

evaluate, evaluate, getData, getDataRef, test, test, test, test

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

serialVersionUID

private static final long serialVersionUID

Serializable version identifier

See Also:

• Constant Field Values

FIXED_QUANTILE_50

private static final double FIXED_QUANTILE_50

Fixed quantile.

See Also:

• Constant Field Values

Constructor Details

Median

public Median()

Default constructor.

Median

public Median(Median original)
       throws NullArgumentException

Copy constructor, creates a new Median identical to the original

Parameters:

original - the Median instance to copy

Throws:

NullArgumentException - if original is null

Median

private Median(Percentile.EstimationType estimationType,
 NaNStrategy nanStrategy,
 KthSelector kthSelector)
        throws MathIllegalArgumentException

Constructs a Median with the specific Percentile.EstimationType, NaNStrategy and

invalid reference

PivotingStrategy

.

Parameters:

estimationType - one of the percentile estimation types

nanStrategy - one of NaNStrategy to handle with NaNs

kthSelector - KthSelector to use for pivoting during search

Throws:

MathIllegalArgumentException - if p is not within (0,100]

NullArgumentException - if type or NaNStrategy passed is null

Method Details

withEstimationType

public Median withEstimationType(Percentile.EstimationType newEstimationType)

Build a new instance similar to the current one except for the estimation type.

This method is intended to be used as part of a fluent-type builder pattern. Building finely tune instances should be done as follows:

  Percentile customized = new Percentile(quantile).
                          withEstimationType(estimationType).
                          withNaNStrategy(nanStrategy).
                          withKthSelector(kthSelector);

If any of the withXxx method is omitted, the default value for the corresponding customization parameter will be used.

Overrides:

withEstimationType in class Percentile

Parameters:

newEstimationType - estimation type for the new instance

Returns:

a new instance, with changed estimation type

withNaNStrategy

public Median withNaNStrategy(NaNStrategy newNaNStrategy)

Build a new instance similar to the current one except for the NaN handling strategy.

This method is intended to be used as part of a fluent-type builder pattern. Building finely tune instances should be done as follows:

  Percentile customized = new Percentile(quantile).
                          withEstimationType(estimationType).
                          withNaNStrategy(nanStrategy).
                          withKthSelector(kthSelector);

If any of the withXxx method is omitted, the default value for the corresponding customization parameter will be used.

Overrides:

withNaNStrategy in class Percentile

Parameters:

newNaNStrategy - NaN strategy for the new instance

Returns:

a new instance, with changed NaN handling strategy

withKthSelector

public Median withKthSelector(KthSelector newKthSelector)

Build a new instance similar to the current one except for the kthSelector instance specifically set.

This method is intended to be used as part of a fluent-type builder pattern. Building finely tune instances should be done as follows:

  Percentile customized = new Percentile(quantile).
                          withEstimationType(estimationType).
                          withNaNStrategy(nanStrategy).
                          withKthSelector(newKthSelector);

If any of the withXxx method is omitted, the default value for the corresponding customization parameter will be used.

Overrides:

withKthSelector in class Percentile

Parameters:

newKthSelector - KthSelector for the new instance

Returns:

a new instance, with changed KthSelector