de.lmu.ifi.dbs.elki.distance.distancefunction.external
Class DiskCacheBasedFloatDistanceFunction<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,FloatDistance>
              de.lmu.ifi.dbs.elki.distance.distancefunction.external.DiskCacheBasedFloatDistanceFunction<V>

Type Parameters:

V - object type

All Implemented Interfaces:

DistanceFunction<V,FloatDistance>, MeasurementFunction<V,FloatDistance>, Parameterizable

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

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

Author:

Erich Schubert

Field Summary

private OnDiskUpperTriangleMatrix	cache
static int	FLOAT_CACHE_MAGIC Magic to identify double cache matrices
private static int	FLOAT_SIZE Storage required for a float 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

DiskCacheBasedFloatDistanceFunction(Parameterization config)
Constructor, adhering to Parameterizable

Method Summary

FloatDistance	distance(Integer id1, Integer id2) Returns the distance between the two objects specified by their objects ids.
FloatDistance	distance(Integer id1, V o2) Returns the distance between the two specified objects.
FloatDistance	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

FLOAT_CACHE_MAGIC

public static final int FLOAT_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

FLOAT_SIZE

private static final int FLOAT_SIZE

Storage required for a float value.

See Also:

Constant Field Values

MATRIX_PARAM

private final FileParameter MATRIX_PARAM

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

Key: -distance.matrix

cache

private OnDiskUpperTriangleMatrix cache

Constructor Detail

DiskCacheBasedFloatDistanceFunction

public DiskCacheBasedFloatDistanceFunction(Parameterization config)

Constructor, adhering to Parameterizable

Parameters:

config - Parameterization

Method Detail

distance

public FloatDistance 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,FloatDistance>

Parameters:

o1 - first DatabaseObject

o2 - second DatabaseObject

Returns:

the distance between two given DatabaseObject according to this distance function

distance

public FloatDistance distance(Integer id1,
                              V o2)

Returns the distance between the two specified objects.

Specified by:

distance in interface DistanceFunction<V extends DatabaseObject,FloatDistance>

Overrides:

distance in class AbstractDistanceFunction<V extends DatabaseObject,FloatDistance>

Parameters:

id1 - first object id

o2 - second DatabaseObject

Returns:

the distance between the two objects specified by their objects ids

distance

public FloatDistance 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,FloatDistance>

Overrides:

distance in class AbstractDistanceFunction<V extends DatabaseObject,FloatDistance>

Parameters:

id1 - first object id

id2 - second object id

Returns:

the distance between the two objects specified by their objects ids