PSquarePercentile (Apache Commons Math 3.6.1 API)

java.lang.Object
- org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic
- - org.apache.commons.math3.stat.descriptive.AbstractStorelessUnivariateStatistic
  - - org.apache.commons.math3.stat.descriptive.rank.PSquarePercentile

All Implemented Interfaces:

Serializable, StorelessUnivariateStatistic, UnivariateStatistic, MathArrays.Function
```
public class PSquarePercentile
extends AbstractStorelessUnivariateStatistic
implements StorelessUnivariateStatistic, Serializable
```
A StorelessUnivariateStatistic estimating percentiles using the P² Algorithm as explained by Raj Jain and Imrich Chlamtac in P² Algorithm for Dynamic Calculation of Quantiles and Histogram Without Storing Observations.
Note: This implementation is not synchronized and produces an approximate result. For small samples, where data can be stored and processed in memory, Percentile should be used.

See Also:
Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static interface`	`PSquarePercentile.PSquareMarkers` An interface that encapsulates abstractions of the P-square algorithm markers as is explained in the original works.

Constructor Summary

Constructors
Constructor and Description

PSquarePercentile(double p)
Constructs a PSquarePercentile with the specific percentile value.

Constructors
Constructor and Description
`PSquarePercentile(double p)` Constructs a PSquarePercentile with the specific percentile value.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clear()` Clears the internal state of the Statistic
`StorelessUnivariateStatistic`	`copy()` Returns a copy of the statistic with the same internal state.
`boolean`	`equals(Object o)` Returns true iff `o` is a `PSquarePercentile` returning the same values as this for `getResult()` and `getN()` and also having equal markers
`long`	`getN()` Returns the number of values that have been added.
`double`	`getResult()` Returns the current value of the Statistic.
`int`	`hashCode()` Returns hash code based on getResult() and getN()
`void`	`increment(double observation)` Updates the internal state of the statistic to reflect the addition of the new value.
`static PSquarePercentile.PSquareMarkers`	`newMarkers(List<Double> initialFive, double p)` A creation method to build Markers
`double`	`quantile()` Returns the quantile estimated by this statistic in the range [0.0-1.0]
`String`	`toString()` Returns a string containing the last observation, the current estimate of the quantile and all markers.

Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractStorelessUnivariateStatistic
evaluate, evaluate, incrementAll, incrementAll

Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic
evaluate, getData, getDataRef, setData, setData, test, test, test, test

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.commons.math3.stat.descriptive.StorelessUnivariateStatistic
incrementAll, incrementAll

Methods inherited from interface org.apache.commons.math3.stat.descriptive.UnivariateStatistic
evaluate, evaluate

- Constructor Detail
  - PSquarePercentile
```
public PSquarePercentile(double p)
```
    Constructs a PSquarePercentile with the specific percentile value.
    
    Parameters:
    p - the percentile
    
    Throws:
    
    OutOfRangeException - if p is not greater than 0 and less than or equal to 100
- Method Detail
  - hashCode
```
public int hashCode()
```
    Returns hash code based on getResult() and getN()
    
    Overrides:
    
    hashCode in class AbstractStorelessUnivariateStatistic
    
    Returns:
    hash code
  - equals
```
public boolean equals(Object o)
```
    Returns true iff o is a PSquarePercentile returning the same values as this for getResult() and getN() and also having equal markers
    
    Overrides:
    
    equals in class AbstractStorelessUnivariateStatistic
    
    Parameters:
    o - object to compare
    
    Returns:
    true if o is a PSquarePercentile with equivalent internal state
  - increment
```
public void increment(double observation)
```
    Updates the internal state of the statistic to reflect the addition of the new value.The internal state updated due to the new value in this context is basically of the marker positions and computation of the approximate quantile.
    
    Specified by:
    
    increment in interface StorelessUnivariateStatistic
    
    Specified by:
    
    increment in class AbstractStorelessUnivariateStatistic
    
    Parameters:
    observation - the observation currently being added.
  - toString
```
public String toString()
```
    Returns a string containing the last observation, the current estimate of the quantile and all markers.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    string representation of state data
  - getN
```
public long getN()
```
    Returns the number of values that have been added.
    
    Specified by:
    
    getN in interface StorelessUnivariateStatistic
    
    Returns:
    the number of values.
  - copy
```
public StorelessUnivariateStatistic copy()
```
    Returns a copy of the statistic with the same internal state.
    
    Specified by:
    
    copy in interface StorelessUnivariateStatistic
    
    Specified by:
    
    copy in interface UnivariateStatistic
    
    Specified by:
    
    copy in class AbstractStorelessUnivariateStatistic
    
    Returns:
    a copy of the statistic
  - quantile
```
public double quantile()
```
    Returns the quantile estimated by this statistic in the range [0.0-1.0]
    
    Returns:
    quantile estimated by getResult()
  - clear
```
public void clear()
```
    Clears the internal state of the Statistic. This basically clears all the markers, the initialFive list and sets countOfObservations to 0.
    
    Specified by:
    
    clear in interface StorelessUnivariateStatistic
    
    Specified by:
    
    clear in class AbstractStorelessUnivariateStatistic
  - getResult
```
public double getResult()
```
    Returns the current value of the Statistic.
    
    Specified by:
    
    getResult in interface StorelessUnivariateStatistic
    
    Specified by:
    
    getResult in class AbstractStorelessUnivariateStatistic
    
    Returns:
    value of the statistic, Double.NaN if it has been cleared or just instantiated.
  - newMarkers
```
public static PSquarePercentile.PSquareMarkers newMarkers(List<Double> initialFive,
                                          double p)
```
    A creation method to build Markers
    
    Parameters:
    initialFive - list of initial five elements
    p - the quantile desired
    
    Returns:
    an instance of PSquareMarkers

Class PSquarePercentile

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractStorelessUnivariateStatistic

Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.commons.math3.stat.descriptive.StorelessUnivariateStatistic

Methods inherited from interface org.apache.commons.math3.stat.descriptive.UnivariateStatistic

Constructor Detail

PSquarePercentile

Method Detail

hashCode

equals

increment

toString

getN

copy

quantile

clear

getResult

newMarkers