jidt/java/source/infodynamics/utils/NearestNeighbourSearcher.java

293 lines
12 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;
import java.util.Collection;
import java.util.PriorityQueue;
/**
* Generic class for fast neighbour searching
* possibly across several (multi-dimensional) variables.
* Instantiates either a sorted array for single dimension data,
* or a k-d tree for multi-dimensional / multiple variables.
* Norms for the nearest neighbour searches are the max norm between
* the (multi-dimensional) variables, and either max norm or Euclidean
* norm (squared) within each variable.
*
* @author Joseph Lizier (<a href="joseph.lizier at gmail.com">email</a>,
* <a href="http://lizier.me/joseph/">www</a>)
*/
public abstract class NearestNeighbourSearcher {
/**
* The norm type to use between the univariates.
*/
protected int normTypeToUse = EuclideanUtils.NORM_MAX_NORM;
/**
* Factory method to construct the searcher from a set of double[][] data.
*
* @param data a double[][] 2D data set, first indexed
* by time, second index by variable number.
*/
public static NearestNeighbourSearcher create(double[][] data)
throws Exception {
if (data[0].length == 1) {
// We have univariate data:
return new UnivariateNearestNeighbourSearcher(MatrixUtils.selectColumn(data, 0));
} else {
return new KdTree(data);
}
}
/**
* Factory method to construct the searcher from a set of double[][][] data.
*
* @param data an array of double[][] 2D data sets, first indexed
* by time, second index by variable number.
*/
public static NearestNeighbourSearcher create(int[] dimensions, double[][][] data)
throws Exception {
if ((dimensions.length == 1) && (dimensions[0] == 1)) {
// We have univariate data:
return new UnivariateNearestNeighbourSearcher(MatrixUtils.selectColumn(data[0], 0));
} else {
return new KdTree(dimensions, data);
}
}
/**
* Set the norm type to use in the nearest neighbour searches,
* to normType.
*
* @param normType norm type to use; must be either
* {@link EuclideanUtils#NORM_EUCLIDEAN},
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} or
* {@link EuclideanUtils#NORM_MAX_NORM}, otherwise an
* UnsupportedOperationException is thrown.
* {@link EuclideanUtils#NORM_EUCLIDEAN} will be nominally supported
* but switched to
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally for speed.
* @throws UnsupportedOperationException if the norm type is not
* one of the above supported options.
*/
public void setNormType(int normType) {
if ((normType != EuclideanUtils.NORM_EUCLIDEAN) &&
(normType != EuclideanUtils.NORM_EUCLIDEAN_SQUARED) &&
(normType != EuclideanUtils.NORM_MAX_NORM)) {
throw new UnsupportedOperationException("Norm type " + normType +
" is not supported in KdTree");
}
if (normType == EuclideanUtils.NORM_EUCLIDEAN) {
normType = EuclideanUtils.NORM_EUCLIDEAN_SQUARED;
}
normTypeToUse = normType;
}
/**
* Set the norm type to use to normType.
*
* @param normType norm type to use; must be either
* {@link EuclideanUtils#NORM_EUCLIDEAN_STRING},
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED_STRING} or
* {@link EuclideanUtils#NORM_MAX_NORM_STRING}, otherwise an
* UnsupportedOperationException is thrown.
* {@link EuclideanUtils#NORM_EUCLIDEAN} will be nominally supported
* but switched to
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally for speed.
* @throws UnsupportedOperationException if the norm type is not
* one of the above supported options.
*/
public void setNormType(String normType) {
normTypeToUse = validateNormType(normType);
}
/**
* Validate whether a specified norm type is supported,
* and return the int corresponding to that type,
* otherwise through an exception.
*
* @param normType norm type to use; must be either
* {@link EuclideanUtils#NORM_EUCLIDEAN_STRING},
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED_STRING} or
* {@link EuclideanUtils#NORM_MAX_NORM_STRING}, otherwise an
* UnsupportedOperationException is thrown.
* {@link EuclideanUtils#NORM_EUCLIDEAN} will be nominally supported
* but switched to
* {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally for speed.
* @throws UnsupportedOperationException if the norm type is not
* one of the above supported options.
*/
public static int validateNormType(String normType) {
if (normType.equalsIgnoreCase(EuclideanUtils.NORM_EUCLIDEAN_STRING)) {
normType = EuclideanUtils.NORM_EUCLIDEAN_SQUARED_STRING;
}
if (normType.equalsIgnoreCase(EuclideanUtils.NORM_EUCLIDEAN_SQUARED_STRING)) {
return EuclideanUtils.NORM_EUCLIDEAN_SQUARED;
}
if (normType.equalsIgnoreCase(EuclideanUtils.NORM_MAX_NORM_STRING)) {
return EuclideanUtils.NORM_MAX_NORM;
}
throw new UnsupportedOperationException("Norm type " + normType +
" is not supported in NearestNeighbourSearcher");
}
/**
* Return the node which is the nearest neighbour for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @return the node for the nearest neighbour.
*/
public abstract NeighbourNodeData findNearestNeighbour(int sampleIndex);
/**
* Return the K nodes which are the K nearest neighbours for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
*
* @param K number of K nearest neighbours to return, sorted from
* furthest away first to nearest last.
* @param sampleIndex sample index in the data to find the K nearest neighbours
* for
* @return a PriorityQueue of nodes for the K nearest neighbours,
* sorted with furthest neighbour first in the PQ.
* @throws Exception
*/
public abstract PriorityQueue<NeighbourNodeData>
findKNearestNeighbours(int K, int sampleIndex) throws Exception;
/**
* Count the number of points within norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param allowEqualToR if true, then count points at radius r also,
* otherwise only those strictly within r
* @return the count of points within r.
*/
public abstract int countPointsWithinR(int sampleIndex, double r,
boolean allowEqualToR);
/**
* Return the collection of points within norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param allowEqualToR if true, then count points at radius r also,
* otherwise only those strictly within r
* @return the collection of points within r.
*/
public abstract Collection<NeighbourNodeData> findPointsWithinR(
int sampleIndex, double r,
boolean allowEqualToR);
/**
* Count the number of points strictly within norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @return the count of points within r.
*/
public abstract int countPointsStrictlyWithinR(int sampleIndex, double r);
/**
* Return the collection of points strictly within norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @return the collection of points within r.
*/
public abstract Collection<NeighbourNodeData> findPointsStrictlyWithinR(int sampleIndex, double r);
/**
* Count the number of points within or at norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @return the count of points within or on r.
*/
public abstract int countPointsWithinOrOnR(int sampleIndex, double r);
/**
* Return the collection of points within or at norm r for a given
* sample index in the data set. The node itself is
* excluded from the search.
* Nearest neighbour function to compare to r is a max norm between the
* high-level variables, with norm for each variable being the specified norm.
* (If {@link EuclideanUtils#NORM_EUCLIDEAN} was selected, then the supplied
* r should be the required Euclidean norm <b>squared</b>, since we switch it
* to {@link EuclideanUtils#NORM_EUCLIDEAN_SQUARED} internally).
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @return the collection of points within or on r.
*/
public abstract Collection<NeighbourNodeData> findPointsWithinOrOnR(int sampleIndex, double r);
}