Package elki.outlier.anglebased

Class FastABOD<V extends NumberVector>

java.lang.Object

elki.outlier.anglebased.ABOD<V>

elki.outlier.anglebased.FastABOD<V>

Type Parameters:

V - Vector type

All Implemented Interfaces:

Algorithm, OutlierAlgorithm

Direct Known Subclasses:

LBABOD

@Title("Approximate ABOD: Angle-Based Outlier Detection")
@Description("Outlier detection using variance analysis on angles, especially for high dimensional data sets.")
@Reference(authors="Hans-Peter Kriegel, Matthias Schubert, Arthur Zimek",
           title="Angle-Based Outlier Detection in High-dimensional Data",
           booktitle="Proc. 14th ACM SIGKDD Int. Conf. Knowledge Discovery and Data Mining (KDD\'08)",
           url="https://doi.org/10.1145/1401890.1401946",
           bibkey="DBLP:conf/kdd/KriegelSZ08")
public class FastABOD<V extends NumberVector>
extends ABOD<V>

Fast-ABOD (approximateABOF) version of Angle-Based Outlier Detection / Angle-Based Outlier Factor.

Note: the minimum k is 3. The 2 nearest neighbors yields one 1 angle, which implies a constant 0 variance everywhere.

Reference:

Hans-Peter Kriegel, Matthias Schubert, Arthur Zimek
Angle-Based Outlier Detection in High-dimensional Data
Proc. 14th ACM SIGKDD Int. Conf. Knowledge Discovery and Data Mining (KDD'08)

Since:

0.6.0

Author:

Matthias Schubert (Original Code), Erich Schubert (ELKIfication)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FastABOD.Par<V extends NumberVector>	Parameterization class.

Nested classes/interfaces inherited from interface elki.Algorithm

Algorithm.Utils

Field Summary

Fields

Modifier and Type	Field	Description
protected int	k	Number of nearest neighbors.

Fields inherited from class elki.outlier.anglebased.ABOD

kernelFunction

Constructor Summary

Constructors

Constructor	Description
FastABOD(Similarity<? super V> kernelFunction, int k)	Constructor for Angle-Based Outlier Detection (ABOD).

Method Summary

Modifier and Type	Method	Description
private void	fastABOD(Relation<V> relation, DBIDs ids, WritableDoubleDataStore abodvalues, DoubleMinMax minmaxabod)	Full kernel-based version.
TypeInformation[]	getInputTypeRestriction()	Get the input type restriction used for negotiating the data query.
private boolean	kNNABOD(Relation<V> relation, DBIDs ids, WritableDoubleDataStore abodvalues, DoubleMinMax minmaxabod)	Simpler kNN based, can use more indexing.
OutlierResult	run(Relation<V> relation)	Run Fast-ABOD on the data set.

Methods inherited from class elki.outlier.anglebased.ABOD

computeABOF

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.outlier.OutlierAlgorithm

autorun

Field Detail

k

protected int k

Number of nearest neighbors.

Constructor Detail

FastABOD

public FastABOD(Similarity<? super V> kernelFunction,
                int k)

Constructor for Angle-Based Outlier Detection (ABOD).

Parameters:

kernelFunction - kernel function to use

k - Number of nearest neighbors

Method Detail

run

public OutlierResult run(Relation<V> relation)

Run Fast-ABOD on the data set.

Overrides:

run in class ABOD<V extends NumberVector>

Parameters:

relation - Relation to process

Returns:

Outlier detection result

kNNABOD

private boolean kNNABOD(Relation<V> relation,
                        DBIDs ids,
                        WritableDoubleDataStore abodvalues,
                        DoubleMinMax minmaxabod)

Simpler kNN based, can use more indexing.

Parameters:

relation - Data relation

ids - IDs

abodvalues - Score storage

minmaxabod - Min/max storage

Returns:

true if kNN were available and usable.

fastABOD

private void fastABOD(Relation<V> relation,
                      DBIDs ids,
                      WritableDoubleDataStore abodvalues,
                      DoubleMinMax minmaxabod)

Full kernel-based version.

Parameters:

relation - Data relation

ids - IDs

abodvalues - Score storage

minmaxabod - Min/max storage

getInputTypeRestriction

public TypeInformation[] getInputTypeRestriction()

Description copied from interface: Algorithm

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

Specified by:

getInputTypeRestriction in interface Algorithm

Overrides:

getInputTypeRestriction in class ABOD<V extends NumberVector>

Returns:

Type restriction