jidt/java/source/infodynamics/utils/NeighbourNodeData.java

79 lines
2.7 KiB
Java
Executable File

/*
* Java Information Dynamics Toolkit (JIDT)
* Copyright (C) 2012, Joseph T. Lizier
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package infodynamics.utils;
/**
* Class for storing nearest neighbour values during the search
*
* @author Joseph Lizier (<a href="joseph.lizier at gmail.com">email</a>,
* <a href="http://lizier.me/joseph/">www</a>)
*/
public class NeighbourNodeData implements Comparable<NeighbourNodeData> {
public int sampleIndex;
public double[] norms; // norms in each high-level variable
public double distance; // Assertion: distance is the max of norms
/**
* Create an instance representing data about one given nearest neighbour
* to another data point.
*
*
* @param sampleIndex index of the neighbour
* @param norms norms between the neighbour and the other data point,
* for each high-level variable.
* @param distance the max of the norms (used for sorting
* NeighbourNodeData objects in a PriorityQueue)
*/
public NeighbourNodeData(int sampleIndex, double[] norms, double distance) {
super();
this.norms = norms;
this.sampleIndex = sampleIndex;
this.distance = distance;
}
/**
* Override's {@link Comparable#compareTo(Object)} to provide
* a natural comparison for the NeighbourNodeData class,
* based on the underlying distance member.
*
* <p><b>IMPORTANT</b> -- we reverse the usual comparison return
* values, returning a positive number if other is greater,
* and a negative number if other is less. This is so that a
* {@link java.util.PriorityQueue} of NeighbourNodeData objects
* will hold that with the largest distance as the head (whereas
* for standard return values from this method it would be
* the other way around).
*
* @param other Other NeighbourNodeData to compare to
*/
@Override
public int compareTo(NeighbourNodeData other) {
if (distance < other.distance) {
// Normally would return -1 here but we flip it -- see
// header comments
return 1;
} else if (distance > other.distance) {
// Normally would return +1 here but we flip it -- see
// header comments
return -1;
}
// distances are equal
return 0;
}
}