PrecisionAtKEvaluation (ELKI: Environment for DeveLoping KDD-Applications Supported by Index-Structures)

java.lang.Object
- elki.evaluation.scores.PrecisionAtKEvaluation

All Implemented Interfaces:

ScoreEvaluation
```
public class PrecisionAtKEvaluation
extends java.lang.Object
implements ScoreEvaluation
```
Evaluate using Precision@k, or R-precision (when k=0).
When k=0, then it is set to the number of positive objects, and the returned value is the R-precision, or the precision-recall break-even-point (BEP).

Since:

0.7.0

Author:

Erich Schubert

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class PrecisionAtKEvaluation.Par
Parameterization class.
- Nested classes/interfaces inherited from interface elki.evaluation.scores.ScoreEvaluation
  ScoreEvaluation.Adapter

Field Summary

Fields
Modifier and Type Field Description

(package private) int k
Parameter k.

static PrecisionAtKEvaluation RPRECISION
Static instance

Constructor Summary

Constructors
Constructor Description

PrecisionAtKEvaluation(int k)
Constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`double`	`evaluate(ScoreEvaluation.Adapter adapter)`	Evaluate a given predicate and iterator.
`double`	`expected(int pos, int all)`	Expected score for a random result.

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

Methods inherited from interface elki.evaluation.scores.ScoreEvaluation
evaluate

- Field Detail
  - RPRECISION
```
public static final PrecisionAtKEvaluation RPRECISION
```
    Static instance
  - k
```
int k
```
    Parameter k.
- Constructor Detail
  - PrecisionAtKEvaluation
```
public PrecisionAtKEvaluation(int k)
```
    Constructor.
    
    Parameters:
    
    k - k to evaluate at. May be 0.
- Method Detail
  - evaluate
```
public double evaluate(ScoreEvaluation.Adapter adapter)
```
    Description copied from interface: ScoreEvaluation
    
    Evaluate a given predicate and iterator.
    
    Specified by:
    
    evaluate in interface ScoreEvaluation
    
    Parameters:
    
    adapter - Input data adapter
    
    Returns:
    
    Score
  - expected
```
public double expected(int pos,
                       int all)
```
    Description copied from interface: ScoreEvaluation
    
    Expected score for a random result.
    
    Specified by:
    
    expected in interface ScoreEvaluation
    
    Parameters:
    
    pos - Number of positive elements
    
    all - Total number of elements
    
    Returns:
    
    Expected score