edu.stanford.math.plex4.metric.landmark

Class MaxMinLandmarkSelector<T>

java.lang.Object

edu.stanford.math.plex4.metric.landmark.LandmarkSelector<T>

edu.stanford.math.plex4.metric.landmark.MaxMinLandmarkSelector<T>

Type Parameters:

T - the type of the underlying metric space

All Implemented Interfaces:

AbstractIntMetricSpace, AbstractObjectMetric<T>, AbstractObjectMetricSpace<T>, AbstractSearchableMetricSpace<T>

public class MaxMinLandmarkSelector<T>
extends LandmarkSelector<T>

This class implements sequential max-min landmark selection of points from a metric space. This method of landmark selection chooses points that are as far spread out as possible, using the following inductive procedure: Suppose that {l_0, ..., l_{i-1}} have been chosen as landmark points. Define the function f(z) = min{d(z, l_0), ...., d(z, l_{i-1}} and define l_i to be l_i = arg max f(z). We start with l_0 being chosen randomly.

Author:

Andrew Tausz

Field Summary

Fields inherited from class edu.stanford.math.plex4.metric.landmark.LandmarkSelector

indexMapping, landmarkSetSize, metricSpace

Constructor Summary

Constructors

Constructor and Description
MaxMinLandmarkSelector(AbstractSearchableMetricSpace<T> metricSpace, int landmarkSetSize) This constructor initializes the landmark selector with a finite metric space, and a size parameter.
MaxMinLandmarkSelector(AbstractSearchableMetricSpace<T> metricSpace, int landmarkSetSize, int firstPoint) This constructor initializes the landmark selector with a finite metric space, and a size parameter.

Method Summary

Methods

Modifier and Type	Method and Description
protected int[]	computeLandmarkSet() This function constructs the set of landmark points.

Methods inherited from class edu.stanford.math.plex4.metric.landmark.LandmarkSelector

distance, distance, getClosedNeighborhood, getKNearestNeighbors, getLandmarkIndex, getLandmarkPoints, getMaxDistanceFromPointsToLandmarks, getNearestPointIndex, getOpenNeighborhood, getPoint, getPoints, getUnderlyingMetricSpace, size

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxMinLandmarkSelector

public MaxMinLandmarkSelector(AbstractSearchableMetricSpace<T> metricSpace,
                      int landmarkSetSize)

This constructor initializes the landmark selector with a finite metric space, and a size parameter.

Parameters:

metricSpace - the metric space to build the landmarks set in

landmarkSetSize - the size of the landmark set

MaxMinLandmarkSelector

public MaxMinLandmarkSelector(AbstractSearchableMetricSpace<T> metricSpace,
                      int landmarkSetSize,
                      int firstPoint)

This constructor initializes the landmark selector with a finite metric space, and a size parameter.

Parameters:

metricSpace - the metric space to build the landmarks set in

landmarkSetSize - the size of the landmark set

firstPoint - the initial point to use

Method Detail

computeLandmarkSet

protected int[] computeLandmarkSet()

Description copied from class: LandmarkSelector

This function constructs the set of landmark points. It must return an array of size landmarkSetSize, which contains the indices of the landmark points within the metric space.

Specified by:

computeLandmarkSet in class LandmarkSelector<T>

Returns:

an array of indices corresponding to the landmark points in the metric space