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:

MatrixLike<Vector>, Serializable, Cloneable

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.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private static long	serialVersionUID Serial version
protected double	wsum The current weight

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

elements

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, Iterable<DBID> 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<? extends F,?>> F	toVector(Relation<? extends F> relation) Get the data as vector

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

clone, copy, equals, euclideanLength, get, get, getArrayCopy, getArrayRef, getColumnDimensionality, getColumnVector, getDimensionality, getRowDimensionality, hashCode, increment, inverseVector, minus, minusEquals, minusEquals, minusTimes, minusTimesEquals, normalize, normF, plus, plusEquals, plusEquals, plusTimes, plusTimesEquals, projection, randomNormalizedVector, scalarProduct, set, set, setZero, sqrtVector, times, times, timesEquals, timesTranspose, toString, toStringNoWhitespace, transpose, transposeTimes, transposeTimes, unitVector

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

Serial version

See Also:

Constant Field Values

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<? extends F,?>> F toVector(Relation<? extends F> relation)

Get the data as vector

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.

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,
            Iterable<DBID> ids)

Static constructor from an existing relation.

Parameters:

relation - Relation to use

ids - IDs to use