de.lmu.ifi.dbs.elki.evaluation.scores

Class PrecisionAtKEvaluation

java.lang.Object

de.lmu.ifi.dbs.elki.evaluation.scores.AbstractScoreEvaluation

de.lmu.ifi.dbs.elki.evaluation.scores.PrecisionAtKEvaluation

All Implemented Interfaces:

ScoreEvaluation

public class PrecisionAtKEvaluation
extends AbstractScoreEvaluation

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).

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PrecisionAtKEvaluation.Parameterizer Parameterization class.

Nested classes/interfaces inherited from interface de.lmu.ifi.dbs.elki.evaluation.scores.ScoreEvaluation

ScoreEvaluation.Predicate<T>, ScoreEvaluation.ScoreIter

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	k Parameter k.
static PrecisionAtKEvaluation	RPRECISION Static instance

Constructor Summary

Constructors

Constructor and Description
PrecisionAtKEvaluation(int k) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
<I extends ScoreEvaluation.ScoreIter> double	evaluate(ScoreEvaluation.Predicate<? super I> predicate, I iter) Evaluate a given predicate and iterator.
double	expected(int pos, int all) Expected score for a random result.

Methods inherited from class de.lmu.ifi.dbs.elki.evaluation.scores.AbstractScoreEvaluation

evaluate, evaluate, evaluate

Methods inherited from class java.lang.Object

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

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 <I extends ScoreEvaluation.ScoreIter> double evaluate(ScoreEvaluation.Predicate<? super I> predicate,
                                                    I iter)

Description copied from interface: ScoreEvaluation

Evaluate a given predicate and iterator.

Type Parameters:

I - Iterator type

Parameters:

predicate - Predicate (for positives)

iter - Iterator

Returns:

Score

expected

public double expected(int pos,
              int all)

Description copied from interface: ScoreEvaluation

Expected score for a random result.

Parameters:

pos - Number of positive elements

all - Total number of elements

Returns:

Expected score