de.lmu.ifi.dbs.elki.algorithm.classification

Class KNNClassifier<O>

java.lang.Object

de.lmu.ifi.dbs.elki.algorithm.AbstractAlgorithm<R>

de.lmu.ifi.dbs.elki.algorithm.AbstractDistanceBasedAlgorithm<O,Result>

de.lmu.ifi.dbs.elki.algorithm.classification.KNNClassifier<O>

Type Parameters:

O - the type of DatabaseObjects handled by this Algorithm

All Implemented Interfaces:

Algorithm, Classifier<O>, DistanceBasedAlgorithm<O>

@Title(value="kNN-classifier")
@Description(value="Lazy classifier classifies a given instance to the majority class of the k-nearest neighbors.")
public class KNNClassifier<O>
extends AbstractDistanceBasedAlgorithm<O,Result>
implements Classifier<O>

KNNClassifier classifies instances based on the class distribution among the k nearest neighbors in a database.

Author:

Arthur Zimek

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KNNClassifier.Parameterizer<O> Parameterization class

Field Summary

Fields

Modifier and Type	Field and Description
protected int	k Holds the value of @link #K_PARAM}.
protected KNNQuery<O>	knnq kNN query class.
protected Relation<? extends ClassLabel>	labelrep Class label representation.
private static Logging	LOG The logger for this class.

Fields inherited from interface de.lmu.ifi.dbs.elki.algorithm.DistanceBasedAlgorithm

DISTANCE_FUNCTION_ID

Constructor Summary

Constructors

Constructor and Description
KNNClassifier(DistanceFunction<? super O> distanceFunction, int k) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	buildClassifier(Database database, Relation<? extends ClassLabel> labels) Performs the training.
ClassLabel	classify(O instance) Classify a single instance.
double[]	classProbabilities(O instance, ArrayList<ClassLabel> labels)
TypeInformation[]	getInputTypeRestriction() Get the input type restriction used for negotiating the data query.
protected Logging	getLogger() Get the (STATIC) logger for this class.
String	model() Produce a String representation of the classification model.
Result	run(Database database) Deprecated.

Methods inherited from class de.lmu.ifi.dbs.elki.algorithm.AbstractDistanceBasedAlgorithm

getDistanceFunction

Methods inherited from class de.lmu.ifi.dbs.elki.algorithm.AbstractAlgorithm

makeParameterDistanceFunction

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final Logging LOG

The logger for this class.

k

protected int k

Holds the value of @link #K_PARAM}.

knnq

protected KNNQuery<O> knnq

kNN query class.

labelrep

protected Relation<? extends ClassLabel> labelrep

Class label representation.

Constructor Detail

KNNClassifier

public KNNClassifier(DistanceFunction<? super O> distanceFunction,
             int k)

Constructor.

Parameters:

distanceFunction - Distance function

k - Number of nearest neighbors to access.

Method Detail

buildClassifier

public void buildClassifier(Database database,
                   Relation<? extends ClassLabel> labels)

Description copied from interface: Classifier

Performs the training. Sets available labels.

Specified by:

buildClassifier in interface Classifier<O>

Parameters:

database - the database to build the model on

labels - the classes to be learned

classify

public ClassLabel classify(O instance)

Description copied from interface: Classifier

Classify a single instance.

Specified by:

classify in interface Classifier<O>

Parameters:

instance - an instance to classify

Returns:

predicted class label of the given instance

classProbabilities

public double[] classProbabilities(O instance,
                          ArrayList<ClassLabel> labels)

model

public String model()

Description copied from interface: Classifier

Produce a String representation of the classification model.

Specified by:

model in interface Classifier<O>

Returns:

a String representation of the classification model

run

@Deprecated
public Result run(Database database)
           throws IllegalStateException

Deprecated.

Description copied from interface: Algorithm

Runs the algorithm.

Specified by:

run in interface Algorithm

Overrides:

run in class AbstractAlgorithm<Result>

Parameters:

database - the database to run the algorithm on

Returns:

the Result computed by this algorithm

Throws:

IllegalStateException

getInputTypeRestriction

public TypeInformation[] getInputTypeRestriction()

Description copied from class: AbstractAlgorithm

Get the input type restriction used for negotiating the data query.

Specified by:

getInputTypeRestriction in interface Algorithm

Specified by:

getInputTypeRestriction in class AbstractAlgorithm<Result>

Returns:

Type restriction

getLogger

protected Logging getLogger()

Description copied from class: AbstractAlgorithm

Get the (STATIC) logger for this class.

Specified by:

getLogger in class AbstractAlgorithm<Result>

Returns:

the static logger