de.lmu.ifi.dbs.elki.distance.distancefunction.external
Class DiskCacheBasedDoubleDistanceFunction<V extends DatabaseObject>

java.lang.Object
  de.lmu.ifi.dbs.elki.logging.AbstractLoggable
      de.lmu.ifi.dbs.elki.distance.AbstractMeasurementFunction<O,D>
          de.lmu.ifi.dbs.elki.distance.distancefunction.AbstractDistanceFunction<V,DoubleDistance>
              de.lmu.ifi.dbs.elki.distance.distancefunction.external.DiskCacheBasedDoubleDistanceFunction<V>

Type Parameters:

V - object type

All Implemented Interfaces:

DistanceFunction<V,DoubleDistance>, MeasurementFunction<V,DoubleDistance>, Parameterizable

@Title(value="File based double distance for database objects.")
@Description(value="Loads double distance values from an external matrix.")
public class DiskCacheBasedDoubleDistanceFunction<V extends DatabaseObject>
extends AbstractDistanceFunction<V,DoubleDistance>
implements Parameterizable

Provides a DistanceFunction that is based on double distances given by a distance matrix of an external file.

Author:

Erich Schubert

Field Summary

private OnDiskUpperTriangleMatrix	cache
static int	DOUBLE_CACHE_MAGIC Magic to identify double cache matrices
private static int	DOUBLE_SIZE Storage required for a double value.
static OptionID	MATRIX_ID OptionID for MATRIX_PARAM
private FileParameter	MATRIX_PARAM Parameter that specifies the name of the directory to be re-parsed.

Fields inherited from class de.lmu.ifi.dbs.elki.distance.AbstractMeasurementFunction

distanceFactory

Fields inherited from class de.lmu.ifi.dbs.elki.logging.AbstractLoggable

debug, logger

Constructor Summary

DiskCacheBasedDoubleDistanceFunction(Parameterization config)
Constructor, adhering to Parameterizable

Method Summary

DoubleDistance	distance(Integer id1, Integer id2) Returns the distance between the two objects specified by their objects ids.
DoubleDistance	distance(Integer id1, V o2) Returns the distance between the two specified objects.
DoubleDistance	distance(V o1, V o2) Computes the distance between two given DatabaseObjects according to this distance function.

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

getDatabase, getDistanceFactory, infiniteDistance, nullDistance, setDatabase, undefinedDistance, valueOf

Methods inherited from class de.lmu.ifi.dbs.elki.logging.AbstractLoggable

debugFine, debugFiner, debugFinest, exception, progress, verbose, warning

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.distance.MeasurementFunction

getDistanceFactory, infiniteDistance, nullDistance, setDatabase, undefinedDistance, valueOf

Field Detail

DOUBLE_CACHE_MAGIC

public static final int DOUBLE_CACHE_MAGIC

Magic to identify double cache matrices

See Also:

Constant Field Values

MATRIX_ID

public static final OptionID MATRIX_ID

OptionID for MATRIX_PARAM

MATRIX_PARAM

private final FileParameter MATRIX_PARAM

Parameter that specifies the name of the directory to be re-parsed.

Key: -distance.matrix

DOUBLE_SIZE

private static final int DOUBLE_SIZE

Storage required for a double value.

See Also:

Constant Field Values

cache

private OnDiskUpperTriangleMatrix cache

Constructor Detail

DiskCacheBasedDoubleDistanceFunction

public DiskCacheBasedDoubleDistanceFunction(Parameterization config)

Constructor, adhering to Parameterizable

Parameters:

config - Parameterization

Method Detail

distance

public DoubleDistance distance(V o1,
                               V o2)

Computes the distance between two given DatabaseObjects according to this distance function.

Specified by:

distance in interface DistanceFunction<V extends DatabaseObject,DoubleDistance>

Parameters:

o1 - first DatabaseObject

o2 - second DatabaseObject

Returns:

the distance between two given DatabaseObject according to this distance function

distance

public DoubleDistance distance(Integer id1,
                               V o2)

Returns the distance between the two specified objects.

Specified by:

distance in interface DistanceFunction<V extends DatabaseObject,DoubleDistance>

Overrides:

distance in class AbstractDistanceFunction<V extends DatabaseObject,DoubleDistance>

Parameters:

id1 - first object id

o2 - second DatabaseObject

Returns:

the distance between the two objects specified by their objects ids

distance

public DoubleDistance distance(Integer id1,
                               Integer id2)

Returns the distance between the two objects specified by their objects ids. If a cache is used, the distance value is looked up in the cache. If the distance does not yet exists in cache, it will be computed an put to cache. If no cache is used, the distance is computed.

Specified by:

distance in interface DistanceFunction<V extends DatabaseObject,DoubleDistance>

Overrides:

distance in class AbstractDistanceFunction<V extends DatabaseObject,DoubleDistance>

Parameters:

id1 - first object id

id2 - second object id

Returns:

the distance between the two objects specified by their objects ids