at.tuwien.ifs.somtoolbox.data.distance

Class LeightWeightMemoryInputVectorDistanceMatrix

java.lang.Object

at.tuwien.ifs.somtoolbox.data.distance.InputVectorDistanceMatrix

at.tuwien.ifs.somtoolbox.data.distance.AbstractMemoryInputVectorDistanceMatrix

at.tuwien.ifs.somtoolbox.data.distance.LeightWeightMemoryInputVectorDistanceMatrix

public class LeightWeightMemoryInputVectorDistanceMatrix
extends AbstractMemoryInputVectorDistanceMatrix

This class implements an AbstractMemoryInputVectorDistanceMatrix using a one-dimensional double array (i.e. double[]).
Similar to RandomAccessFileInputVectorDistanceMatrix, the storage is sparse, not containing the diagonal and the lower half, i.e. as follows:

 [(2,1) (3,1) (4,1) (5,1) (6,1)]
 [      (3,2) (4,2) (5,1) (6,2)]
 [            (4,3) (5,3) (6,3)]
 [                  (5,4) (6,4)]
 [                        (6,5)]
 [                             ]
 

Thus, there are (n-1)! double values. If this is still too much memory consumption, consider using RandomAccessFileInputVectorDistanceMatrix instead.
Compared to FullMemoryInputVectorDistanceMatrix, the memory consumption is lower, and getDistancesFlat() is very fast, while getDistances(int) needs to be constructed on the fly.

Version:

$Id: LeightWeightMemoryInputVectorDistanceMatrix.java 3704 2010-07-20 10:42:42Z mayer $

Author:

Rudolf Mayer

Field Summary

Fields

Modifier and Type	Field and Description
(package private) double[]	distances

Fields inherited from class at.tuwien.ifs.somtoolbox.data.distance.AbstractMemoryInputVectorDistanceMatrix

FILE_TYPE

Fields inherited from class at.tuwien.ifs.somtoolbox.data.distance.InputVectorDistanceMatrix

inputLabels, metric, numVectors

Constructor Summary

Constructors

Constructor and Description
LeightWeightMemoryInputVectorDistanceMatrix(InputData data, DistanceMetric metric)
LeightWeightMemoryInputVectorDistanceMatrix(java.lang.String fileName)

Method Summary

Modifier and Type	Method and Description
double	getDistance(int x, int y) Finds the index in vector for the matrix position (x,y); see distances
double[]	getDistances(int x) This implementation is not of good performance, as the matrix row is always constructed on the fly.
double[]	getDistancesFlat() This implementation is of high performance, as it returns only the already internally constructed array.
protected int	getMatrixIndex(int x, int y)
protected void	initStorage()
protected void	setValue(int x, int y, double value)
java.lang.String	toString()

Methods inherited from class at.tuwien.ifs.somtoolbox.data.distance.InputVectorDistanceMatrix

columns, equals, flatArraySize, getDistancesFlatAsMatrix, getInputLabels, getMetric, getNNearest, initFromFile, numVectors, rows

Methods inherited from class java.lang.Object

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

Field Detail

distances

double[] distances

Constructor Detail

LeightWeightMemoryInputVectorDistanceMatrix

public LeightWeightMemoryInputVectorDistanceMatrix(InputData data,
                                                   DistanceMetric metric)
                                            throws MetricException

Throws:

MetricException

LeightWeightMemoryInputVectorDistanceMatrix

public LeightWeightMemoryInputVectorDistanceMatrix(java.lang.String fileName)
                                            throws java.io.IOException,
                                                   SOMToolboxException

Throws:

java.io.IOException

SOMToolboxException

Method Detail

setValue

protected void setValue(int x,
                        int y,
                        double value)

Specified by:

setValue in class AbstractMemoryInputVectorDistanceMatrix

initStorage

protected void initStorage()

Specified by:

initStorage in class AbstractMemoryInputVectorDistanceMatrix

getDistance

public double getDistance(int x,
                          int y)

Finds the index in vector for the matrix position (x,y); see distances

Specified by:

getDistance in class InputVectorDistanceMatrix

getMatrixIndex

protected int getMatrixIndex(int x,
                             int y)

getDistances

public double[] getDistances(int x)

This implementation is not of good performance, as the matrix row is always constructed on the fly. If you need to use this method often, consider using a FullMemoryInputVectorDistanceMatrix instead

Overrides:

getDistances in class InputVectorDistanceMatrix

getDistancesFlat

public double[] getDistancesFlat()

This implementation is of high performance, as it returns only the already internally constructed array.

Overrides:

getDistancesFlat in class InputVectorDistanceMatrix

See Also:

InputVectorDistanceMatrix.getDistancesFlat()

toString

public java.lang.String toString()

Overrides:

toString in class InputVectorDistanceMatrix