de.lmu.ifi.dbs.elki.distance
Class SubspaceDistance

java.lang.Object
  de.lmu.ifi.dbs.elki.distance.AbstractDistance<SubspaceDistance>
      de.lmu.ifi.dbs.elki.distance.SubspaceDistance

All Implemented Interfaces:

Distance<SubspaceDistance>, Externalizable, Serializable, Comparable<SubspaceDistance>

public class SubspaceDistance
extends AbstractDistance<SubspaceDistance>

The subspace distance is a special distance that indicates the dissimilarity between subspaces of equal dimensionality. The subspace distance between two points is a pair consisting of the distance between the two subspaces spanned by the strong eigenvectors of the two points and the affine distance between the two subspaces.

Author:

Elke Achtert

See Also:

Serialized Form

Field Summary

private double	affineDistance The affine distance.
static Pattern	SEPARATOR Indicates a separator.
private static long	serialVersionUID
private double	subspaceDistance The subspace distance.

Constructor Summary

SubspaceDistance()
Empty constructor for serialization purposes.

SubspaceDistance(double subspaceDistance, double affineDistance)
Constructs a new SubspaceDistance object consisting of the specified subspace distance and affine distance.

Method Summary

int	compareTo(SubspaceDistance other) Compares this SubspaceDistance with the given SubspaceDistance wrt the represented subspace distance values.
String	description() Returns a String as description of this Distance.
int	externalizableSize() Returns the number of Bytes this distance uses if it is written to an external file.
double	getAffineDistance() Returns the value of the affine distance.
double	getSubspaceDistance() Returns the value of the subspace distance.
int	hashCode() Any extending class should implement a proper hashCode method.
SubspaceDistance	minus(SubspaceDistance distance) Returns a new Distance by subtracting the given distance from this distance.
SubspaceDistance	plus(SubspaceDistance distance) Returns a new distance as sum of this distance and the given distance.
void	readExternal(ObjectInput in) Reads the subspace distance value and the affine distance value of this SubspaceDistance from the specified stream.
String	toString() Returns a string representation of this SubspaceDistance.
void	writeExternal(ObjectOutput out) Writes the subspace distance value and the affine distance value of this SubspaceDistance to the specified stream.

Methods inherited from class de.lmu.ifi.dbs.elki.distance.AbstractDistance

equals

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

SEPARATOR

public static final Pattern SEPARATOR

Indicates a separator.

subspaceDistance

private double subspaceDistance

The subspace distance.

affineDistance

private double affineDistance

The affine distance.

Constructor Detail

SubspaceDistance

public SubspaceDistance()

Empty constructor for serialization purposes.

SubspaceDistance

public SubspaceDistance(double subspaceDistance,
                        double affineDistance)

Constructs a new SubspaceDistance object consisting of the specified subspace distance and affine distance.

Parameters:

subspaceDistance - the distance between the two subspaces spanned by the strong eigenvectors of the two points

affineDistance - the affine distance between the two subspaces

Method Detail

plus

public SubspaceDistance plus(SubspaceDistance distance)

Description copied from interface: Distance

Returns a new distance as sum of this distance and the given distance.

Parameters:

distance - the distance to be added to this distance

Returns:

a new distance as sum of this distance and the given distance

minus

public SubspaceDistance minus(SubspaceDistance distance)

Description copied from interface: Distance

Returns a new Distance by subtracting the given distance from this distance.

Parameters:

distance - the distance to be subtracted from this distance

Returns:

a new Distance by subtracting the given distance from this distance

description

public String description()

Description copied from interface: Distance

Returns a String as description of this Distance.

Returns:

a String as description of this Distance

toString

public String toString()

Returns a string representation of this SubspaceDistance.

Specified by:

toString in interface Distance<SubspaceDistance>

Overrides:

toString in class Object

Returns:

the values of the subspace distance and the affine distance separated by blank

compareTo

public int compareTo(SubspaceDistance other)

Compares this SubspaceDistance with the given SubspaceDistance wrt the represented subspace distance values. If both values are considered to be equal, the values of the affine distances are compared.

Returns:

the value of Double.compare(this.subspaceDistance, other.subspaceDistance) if it is a non zero value, the value of Double.compare(this.affineDistance, other.affineDistance) otherwise

hashCode

public int hashCode()

Description copied from class: AbstractDistance

Any extending class should implement a proper hashCode method.

Specified by:

hashCode in class AbstractDistance<SubspaceDistance>

getSubspaceDistance

public double getSubspaceDistance()

Returns the value of the subspace distance.

Returns:

the value of the subspace distance

getAffineDistance

public double getAffineDistance()

Returns the value of the affine distance.

Returns:

the value of the affine distance

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Writes the subspace distance value and the affine distance value of this SubspaceDistance to the specified stream.

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException

Reads the subspace distance value and the affine distance value of this SubspaceDistance from the specified stream.

Throws:

IOException

externalizableSize

public int externalizableSize()

Returns the number of Bytes this distance uses if it is written to an external file.

Returns:

16 (2 * 8 Byte for two double values)