de.lmu.ifi.dbs.elki.math.linearalgebra

Class Centroid

java.lang.Object

de.lmu.ifi.dbs.elki.math.linearalgebra.Vector

de.lmu.ifi.dbs.elki.math.linearalgebra.Centroid

All Implemented Interfaces:

FeatureVector<Number>, NumberVector, SpatialComparable

Direct Known Subclasses:

ProjectedCentroid

public class Centroid
extends Vector

Class to compute the centroid of some data. Note: this class abstracts the efficient and numerical stable computation of centroids. See DatabaseUtil for easier to use APIs.

Author:

Erich Schubert

Nested Class Summary

Nested classes/interfaces inherited from class de.lmu.ifi.dbs.elki.math.linearalgebra.Vector

Vector.ShortSerializer, Vector.SmallSerializer, Vector.VariableSerializer

Field Summary

Fields

Modifier and Type	Field and Description
protected double	wsum The current weight.

Fields inherited from class de.lmu.ifi.dbs.elki.math.linearalgebra.Vector

BYTE_SERIALIZER, elements, ERR_MATRIX_INNERDIM, ERR_VEC_DIMENSIONS, FACTORY, SHORT_SERIALIZER, VARIABLE_SERIALIZER

Constructor Summary

Constructors

Constructor and Description
Centroid(int dim) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
static Centroid	make(Matrix mat) Static Constructor from an existing matrix columns.
static Centroid	make(Relation<? extends NumberVector> relation) Static constructor from an existing relation.
static Centroid	make(Relation<? extends NumberVector> relation, DBIDs ids) Static constructor from an existing relation.
void	put(double[] val) Add a single value with weight 1.0.
void	put(double[] val, double weight) Add data with a given weight.
void	put(NumberVector val) Add a single value with weight 1.0.
void	put(NumberVector val, double weight) Add data with a given weight.
void	put(Vector val) Add a single value with weight 1.0.
void	put(Vector val, double weight) Add data with a given weight.
<F extends NumberVector> F	toVector(Relation<? extends F> relation) Get the data as vector.

Methods inherited from class de.lmu.ifi.dbs.elki.math.linearalgebra.Vector

byteValue, clone, copy, cross3D, doubleValue, equals, euclideanLength, floatValue, get, getArrayCopy, getArrayRef, getColumnVector, getDimensionality, getMax, getMin, getValue, hashCode, intValue, longValue, minus, minusEquals, minusEquals, minusTimes, minusTimesEquals, normalize, plus, plusEquals, plusEquals, plusTimes, plusTimesEquals, projection, randomNormalizedVector, rotate90Equals, set, set, setZero, shortValue, squaredEuclideanLength, times, times, timesEquals, timesTranspose, timesTranspose, toString, toStringNoWhitespace, transposeTimes, transposeTimes, transposeTimesTimes, unitVector

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

wsum

protected double wsum

The current weight.

Constructor Detail

Centroid

public Centroid(int dim)

Constructor.

Parameters:

dim - Dimensionality

Method Detail

put

public void put(double[] val)

Add a single value with weight 1.0.

Parameters:

val - Value

put

public void put(double[] val,
       double weight)

Add data with a given weight.

Parameters:

val - data

weight - weight

put

public final void put(Vector val)

Add a single value with weight 1.0.

Parameters:

val - Value

put

public final void put(Vector val,
       double weight)

Add data with a given weight.

Parameters:

val - data

weight - weight

put

public void put(NumberVector val)

Add a single value with weight 1.0.

Parameters:

val - Value

put

public void put(NumberVector val,
       double weight)

Add data with a given weight.

Parameters:

val - data

weight - weight

toVector

public <F extends NumberVector> F toVector(Relation<? extends F> relation)

Get the data as vector.

Type Parameters:

F - vector type

Parameters:

relation - Data relation

Returns:

the data

make

public static Centroid make(Matrix mat)

Static Constructor from an existing matrix columns.

Parameters:

mat - Matrix to use the columns from.

Returns:

Centroid vector

make

public static Centroid make(Relation<? extends NumberVector> relation)

Static constructor from an existing relation.

Parameters:

relation - Relation to use

Returns:

Centroid of relation

make

public static Centroid make(Relation<? extends NumberVector> relation,
            DBIDs ids)

Static constructor from an existing relation.

Parameters:

relation - Relation to use

ids - IDs to use

Returns:

Centroid