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

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

All Implemented Interfaces:

WeightFunction, InspectionUtilFrequentlyScanned

public final class QuadraticStddevWeight
extends Object
implements WeightFunction

Quadratic weight function, scaled using the standard deviation. We needed another scaling here, we chose the cutoff point to be 3*stddev. If you need another value, you have to reimplement this class. max(0.0, 1.0 - (distance/(3*stddev))^2

Field Summary

private static double

scaling Scaling: at scaling * stddev the function will hit 0.0

Constructor Summary

QuadraticStddevWeight()

Method Summary

double

getWeight(double distance, double max, double stddev) Evaluate weight function at given parameters. max is ignored.

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

Scaling: at scaling * stddev the function will hit 0.0

See Also:

Constant Field Values

Constructor Detail

QuadraticStddevWeight

public QuadraticStddevWeight()

Method Detail

getWeight

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

Evaluate weight function at given parameters. 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