de.lmu.ifi.dbs.elki.algorithm.outlier.lof

Class SimplifiedLOF<O>

java.lang.Object

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

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

de.lmu.ifi.dbs.elki.algorithm.outlier.lof.SimplifiedLOF<O>

Type Parameters:

O - the type of data objects handled by this algorithm

All Implemented Interfaces:

Algorithm, DistanceBasedAlgorithm<O>, OutlierAlgorithm

@Reference(authors="E. Schubert, A. Zimek, H.-P. Kriegel",
           title="Local Outlier Detection Reconsidered: a Generalized View on Locality with Applications to Spatial, Video, and Network Outlier Detection",
           booktitle="Data Mining and Knowledge Discovery, 28(1): 190\u2013237, 2014.",
           url="http://dx.doi.org/10.1007/s10618-012-0300-z")
@Alias(value={"SimplifiedLOF","outlier.SimplifiedLOF","de.lmu.ifi.dbs.elki.algorithm.outlier.SimplifiedLOF"})
public class SimplifiedLOF<O>
extends AbstractDistanceBasedAlgorithm<O,OutlierResult>
implements OutlierAlgorithm

A simplified version of the original LOF algorithm, which does not use the reachability distance, yielding less stable results on inliers. Reference:

Erich Schubert, Arthur Zimek, Hans-Peter Kriegel
Local Outlier Detection Reconsidered: a Generalized View on Locality with Applications to Spatial, Video, and Network Outlier Detection
Data Mining and Knowledge Discovery, 28(1): 190–237, 2014.

Author:

Erich Schubert

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
protected int	k The number of neighbors to query, excluding the query point.
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
SimplifiedLOF(int k, DistanceFunction<? super O> distance) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
private void	computeSimplifiedLOFs(DBIDs ids, KNNQuery<O> knnq, WritableDoubleDataStore slrds, WritableDoubleDataStore lofs, DoubleMinMax lofminmax) Compute the simplified LOF factors.
private void	computeSimplifiedLRDs(DBIDs ids, KNNQuery<O> knnq, WritableDoubleDataStore lrds) Compute the simplified reachability densities.
TypeInformation[]	getInputTypeRestriction() Get the input type restriction used for negotiating the data query.
protected Logging	getLogger() Get the (STATIC) logger for this class.
OutlierResult	run(Database database, Relation<O> relation) Run the Simple LOF algorithm.

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

getDistanceFunction

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

makeParameterDistanceFunction, run

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.lmu.ifi.dbs.elki.algorithm.outlier.OutlierAlgorithm

run

Field Detail

LOG

private static final Logging LOG

The logger for this class.

k

protected int k

The number of neighbors to query, excluding the query point.

Constructor Detail

SimplifiedLOF

public SimplifiedLOF(int k,
             DistanceFunction<? super O> distance)

Constructor.

Parameters:

k - the value of k

Method Detail

run

public OutlierResult run(Database database,
                Relation<O> relation)

Run the Simple LOF algorithm.

Parameters:

database - Database to query

relation - Data to process

Returns:

LOF outlier result

computeSimplifiedLRDs

private void computeSimplifiedLRDs(DBIDs ids,
                         KNNQuery<O> knnq,
                         WritableDoubleDataStore lrds)

Compute the simplified reachability densities.

Parameters:

ids - IDs to process

knnq - kNN query class

lrds - Density output

computeSimplifiedLOFs

private void computeSimplifiedLOFs(DBIDs ids,
                         KNNQuery<O> knnq,
                         WritableDoubleDataStore slrds,
                         WritableDoubleDataStore lofs,
                         DoubleMinMax lofminmax)

Compute the simplified LOF factors.

Parameters:

ids - IDs to compute for

knnq - kNN query class

slrds - Object densities

lofs - SLOF output storage

lofminmax - Minimum and maximum scores

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<OutlierResult>

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<OutlierResult>

Returns:

the static logger