de.lmu.ifi.dbs.elki.math.linearalgebra.pca.weightfunctions
Class GaussStddevWeight

java.lang.Object
  de.lmu.ifi.dbs.elki.math.linearalgebra.pca.weightfunctions.GaussStddevWeight

All Implemented Interfaces:

WeightFunction

public final class GaussStddevWeight
extends Object
implements WeightFunction

Gaussian Weight function, scaled such using standard deviation factor * exp(-.5 * (distance/stddev)^2) with factor being 1 / sqrt(2 * PI)

Author:

Erich Schubert

Field Summary

private static double

scaling Constant scaling factor of Gaussian distribution.

Constructor Summary

GaussStddevWeight()

Method Summary

double

getWeight(double distance, double max, double stddev) Get Gaussian Weight using standard deviation for scaling.

Methods inherited from class java.lang.Object

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

Field Detail

scaling

private static final double scaling

Constant scaling factor of Gaussian distribution. In fact, in most use cases we could leave this away.

Constructor Detail

GaussStddevWeight

public GaussStddevWeight()

Method Detail

getWeight

public double getWeight(double distance,
                        double max,
                        double stddev)

Get Gaussian Weight using standard deviation for scaling. max is ignored.

Specified by:

getWeight in interface WeightFunction

Parameters:

distance - distance of the query point

max - maximum distance of all included points

stddev - standard deviation (i.e. quadratic mean / RMS) of the included points

Returns:

weight for the query point