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

Class ISOS<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.intrinsic.ISOS<O>

Type Parameters:

O - Object type.

All Implemented Interfaces:

Algorithm, DistanceBasedAlgorithm<O>, OutlierAlgorithm

@Title(value="ISOS: Intrinsic Stochastic Outlier Selection")
 @Reference(authors="Erich Schubert, Michael Gertz",
           title="Intrinsic t-Stochastic Neighbor Embedding for Visualization and Outlier Detection: A Remedy Against the Curse of Dimensionality?",
           booktitle="Proc. Int. Conf. Similarity Search and Applications, SISAP\'2017",
           url="https://doi.org/10.1007/978-3-319-68474-1_13",
           bibkey="DBLP:conf/sisap/SchubertG17")
public class ISOS<O>
extends AbstractDistanceBasedAlgorithm<O,OutlierResult>
implements OutlierAlgorithm

Intrinsic Stochastic Outlier Selection.

Reference:

Erich Schubert, Michael Gertz
Intrinsic t-Stochastic Neighbor Embedding for Visualization and Outlier Detection: A Remedy Against the Curse of Dimensionality?
Proc. Int. Conf. Similarity Search and Applications, SISAP'2017

Since:

0.7.5

Author:

Erich Schubert

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
(package private) IntrinsicDimensionalityEstimator	estimator Estimator of intrinsic dimensionality.
protected int	k Number of neighbors (not including query point).
private static Logging	LOG Class logger.
protected double	phi Expected outlier rate.

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

ALGORITHM_ID

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

DISTANCE_FUNCTION_ID

Constructor Summary

Constructors

Constructor and Description
ISOS(DistanceFunction<? super O> distance, int k, IntrinsicDimensionalityEstimator estimator) Constructor.

Method Summary

Modifier and Type	Method and Description
protected static void	adjustDistances(DBIDRef ignore, DoubleDBIDListIter ki, double max, double id, ModifiableDoubleDBIDList dists)
protected double	estimateID(DBIDRef ignore, DoubleDBIDListIter it, double[] p) Estimate the local intrinsic dimensionality.
TypeInformation[]	getInputTypeRestriction() Get the input type restriction used for negotiating the data query.
protected Logging	getLogger() Get the (STATIC) logger for this class.
static void	nominateNeighbors(DBIDIter ignore, DBIDArrayIter di, double[] p, double norm, WritableDoubleDataStore scores) Vote for neighbors not being outliers.
OutlierResult	run(Relation<O> relation) Run the algorithm.
static DoubleMinMax	transformScores(WritableDoubleDataStore scores, DBIDs ids, double logPerp, double phi) Transform scores

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

getDistanceFunction

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

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

Class logger.

k

protected int k

Number of neighbors (not including query point).

estimator

IntrinsicDimensionalityEstimator estimator

Estimator of intrinsic dimensionality.

phi

protected double phi

Expected outlier rate.

Constructor Detail

ISOS

public ISOS(DistanceFunction<? super O> distance,
            int k,
            IntrinsicDimensionalityEstimator estimator)

Constructor.

Parameters:

distance - Distance function

k - Number of neighbors to consider

estimator - Estimator of intrinsic dimensionality.

Method Detail

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

run

public OutlierResult run(Relation<O> relation)

Run the algorithm.

Parameters:

relation - data relation.

Returns:

outlier detection result

adjustDistances

protected static void adjustDistances(DBIDRef ignore,
                                      DoubleDBIDListIter ki,
                                      double max,
                                      double id,
                                      ModifiableDoubleDBIDList dists)

estimateID

protected double estimateID(DBIDRef ignore,
                            DoubleDBIDListIter it,
                            double[] p)

Estimate the local intrinsic dimensionality.

Parameters:

ignore - Object to ignore

it - Iterator

p - Scratch array

Returns:

ID estimate

nominateNeighbors

public static void nominateNeighbors(DBIDIter ignore,
                                     DBIDArrayIter di,
                                     double[] p,
                                     double norm,
                                     WritableDoubleDataStore scores)

Vote for neighbors not being outliers. The key method of SOS.

Parameters:

ignore - Object to ignore

di - Neighbor object IDs.

p - Probabilities

norm - Normalization factor (1/sum)

scores - Output score storage

transformScores

public static DoubleMinMax transformScores(WritableDoubleDataStore scores,
                                           DBIDs ids,
                                           double logPerp,
                                           double phi)

Transform scores

Parameters:

scores - Scores to transform

ids - DBIDs to process

logPerp - log perplexity

phi - Expected outlier rate

Returns:

Minimum and maximum scores

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