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

592 lines
23 KiB
Java

/*
* 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.
* This will return a {@link KdTree} or if the data is univaraite
* (i.e. only one column) a {@link UnivariateNearestNeighbourSearcher}
*
* @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 == null) || (data[0].length == 0)) {
// We have null data:
return null;
} else 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);
}
/**
*
* @return the norm type in use
*/
public int getNormType() {
return normTypeToUse;
}
/**
*
* @return the norm type in use as a String
*/
public String getNormTypeAsString() {
return convertNormTypeToString(normTypeToUse);
}
/**
* 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");
}
/**
* @param an identifier for a norm type
* @return representation of that norm type as a String
*/
public static String convertNormTypeToString(int normType) {
if (normType == EuclideanUtils.NORM_EUCLIDEAN_SQUARED) {
return EuclideanUtils.NORM_EUCLIDEAN_SQUARED_STRING;
} else if (normType == EuclideanUtils.NORM_EUCLIDEAN) {
return EuclideanUtils.NORM_EUCLIDEAN_STRING;
} else if (normType == EuclideanUtils.NORM_MAX_NORM) {
return EuclideanUtils.NORM_MAX_NORM_STRING;
}
// Execution should never reach this point as we control
// what normTypeToUse gets set to; it might be possible though
// if a child class mis-handles the value
throw new Error("normTypeToUse set to an invalid value: " + normType);
}
/**
* 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;
/**
* Return the K nodes which are the K nearest neighbours for a given
* sample index in the data set. Nodes within dynCorrExclTime time points
* are 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
* @param dynCorrExclTime Range around sampleIndex to exclude points from the count. Is >= 0.
* @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, int dynCorrExclTime) 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);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however any nodes within dynCorrExclTime are excluded from
* the search.
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @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,
int dynCorrExclTime, boolean allowEqualToR);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however the search is to match a specified sample point (not a sample
* point within the search space itself).
*
* @param sampleVectors sample vectors to find the neighbours within r
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @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(double[][] sampleVectors, double r,
boolean allowEqualToR);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however returns a collection rather than a count.
*
* @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);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however records the nearest neighbours made within the isWithinR
* and indicesWithinR arrays, which must be constructed before
* calling this method, with length at or exceeding the total
* number of data points. indicesWithinR is
* </p>
*
* @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
* @param isWithinR the array MUST be passed in with all points set to
* false initially, and is returned indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param indicesWithinR a list of array indices
* for points marked as true in isWithinR, terminated with a -1 value.
* @return the number of matching points found
*/
public abstract int findPointsWithinR(
int sampleIndex, double r,
boolean allowEqualToR, boolean[] isWithinR, int[] indicesWithinR);
/**
* As per {@link #findPointsWithinR(int, double, boolean, boolean[], int[])}
* however incorporates dynamic correlation exclusion.
* </p>
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @param allowEqualToR if true, then count points at radius r also,
* otherwise only those strictly within r
* @param isWithinR the array MUST be passed in with all points set to
* false initially, and is returned indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param indicesWithinR a list of array indices
* for points marked as true in isWithinR, terminated with a -1 value.
*/
public abstract void findPointsWithinR(
int sampleIndex, double r, int dynCorrExclTime,
boolean allowEqualToR, boolean[] isWithinR, int[] indicesWithinR);
/**
* As per {@link #findPointsWithinR(int, double, boolean, boolean[], int[])}
* however incorporates dynamic correlation exclusion.
* </p>
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @param allowEqualToR if true, then count points at radius r also,
* otherwise only those strictly within r
* @param isWithinR the array MUST be passed in with all points set to
* false initially, and is returned indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param distancesWithinRInOrder the array must be passed in and is
* returned with distances for each point found to be within r. Values
* at other indices are not defined.
* @param distancesAndIndicesWithinR is returned as
* a list of distances (in column index 0)
* and array indices (in column index 1)
* for points marked as true in isWithinR, terminated with a -1 value on the index.
* @return the point count
*/
public abstract int findPointsWithinR(
int sampleIndex, double r, int dynCorrExclTime,
boolean allowEqualToR, boolean[] isWithinR,
double[] distancesWithinRInOrder,
double[][] distancesAndIndicesWithinR);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however records the nearest neighbours for a sample data point
* (which may not be in the search tree), within the isWithinR
* and indicesWithinR arrays, which must be constructed before
* calling this method, with length at or exceeding the total
* number of data points. indicesWithinR is
* </p>
*
* @param r radius within which to count points
* @param sampleVectors sample vectors to find the neighbours within r
* for
* @param allowEqualToR if true, then count points at radius r also,
* otherwise only those strictly within r
* @param isWithinR the array MUST be passed in with all points set to
* false initially, and is returned indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param indicesWithinR a list of array indices
* for points marked as true in isWithinR, terminated with a -1 value.
*/
public abstract void findPointsWithinR(
double r, double[][] sampleVectors,
boolean allowEqualToR, boolean[] isWithinR, int[] indicesWithinR);
/**
* As per {@link #countPointsWithinR(int, double, int, boolean)}
* with allowEqualToR == false
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @return the count of points within r.
*/
public int countPointsStrictlyWithinR(int sampleIndex, double r,
int dynCorrExclTime) {
return countPointsWithinR(sampleIndex, r, dynCorrExclTime, false);
}
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* with allowEqualToR == false
*
* @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 int countPointsStrictlyWithinR(int sampleIndex, double r) {
return countPointsWithinR(sampleIndex, r, false);
}
/**
* As per {@link #findPointsStrictlyWithinR(int, double) }
* with allowEqualToR == false
*
* @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 Collection<NeighbourNodeData> findPointsStrictlyWithinR(
int sampleIndex, double r) {
return findPointsWithinR(sampleIndex, r, false);
}
/**
* As per {@link #findPointsWithinR(int, double, boolean, boolean[], int[]) }
* with allowEqualToR == false
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param isWithinR the array should be passed in with all points set to
* false initially, and is return indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param indicesWithinR a list of array indices
* for points marked as true in isWithinR, terminated with a -1 value.
*/
public void findPointsStrictlyWithinR(
int sampleIndex, double r, boolean[] isWithinR, int[] indicesWithinR) {
findPointsWithinR(sampleIndex, r, false, isWithinR,
indicesWithinR);
}
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* with allowEqualToR == true
*
* @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 int countPointsWithinOrOnR(int sampleIndex, double r) {
return countPointsWithinR(sampleIndex, r, true);
}
/**
* As per {@link #countPointsWithinR(int, double, int, boolean)}
* with allowEqualToR == true
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param dynCorrExclTime time window within which to exclude
* points to be counted. Is >= 0. 0 means only exclude sampleIndex.
* @return the count of points within or on r.
*/
public int countPointsWithinOrOnR(int sampleIndex, double r,
int dynCorrExclTime) {
return countPointsWithinR(sampleIndex, r, dynCorrExclTime, true);
}
/**
* As per {@link #findPointsStrictlyWithinR(int, double) }
* with allowEqualToR == true
*
* @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 Collection<NeighbourNodeData> findPointsWithinOrOnR(
int sampleIndex, double r) {
return findPointsWithinR(sampleIndex, r, true);
}
/**
* As per {@link #findPointsWithinR(int, double, boolean, boolean[], int[]) }
* with allowEqualToR == true
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for
* @param r radius within which to count points
* @param isWithinR the array should be passed in with all points set to
* false initially, and is return indicating whether each sample was
* found to be within r of that at sampleIndex.
* @param indicesWithinR a list of array indices
* for points marked as true in isWithinR, terminated with a -1 value.
*/
public void findPointsWithinOrOnR(int sampleIndex, double r,
boolean[] isWithinR, int[] indicesWithinR) {
findPointsWithinR(sampleIndex, r, true, isWithinR,
indicesWithinR);
}
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however each point is subject to also meeting the additional
* criteria of being true in additionalCriteria.
*
* @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
* @param additionalCriteria array of booleans. Only count a point if it
* is within r and is true in additionalCrtieria.
* @return the count of points within r.
*/
public abstract int countPointsWithinR(int sampleIndex, double r,
boolean allowEqualToR, boolean[] additionalCriteria);
/**
* As per {@link #countPointsWithinR(int, double, boolean)}
* however each point is subject to also meeting the additional
* criteria of being true in additionalCriteria,
* and the search points are reindexed according to the remapping
* specified in remapping
*
* @param sampleIndex sample index in the data to find a nearest neighbour
* for (already remapped if required)
* @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
* @param additionalCriteria array of booleans. Only count a point if it
* is within r and is true in additionalCrtieria.
* @param remapping array of time indices with which to remap the search points
* onto the same time index space as the additionalCriteria (this will
* apply to the supplied sampleIndex as well as other search points)
* @return the count of points within r.
*/
public abstract int countPointsWithinR(int sampleIndex, double r,
boolean allowEqualToR, boolean[] additionalCriteria,
int[] remapping);
/**
* As per {@link #countPointsWithinR(double[][], double, boolean)}
* however each point is subject to also meeting the additional
* criteria of being true in additionalCriteria.
*
* @param sampleVectors sample vectors to find the neighbours within r
* 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
* @param additionalCriteria array of booleans. Only count a point if it
* is within r and is true in additionalCrtieria.
* @return the count of points within r.
*/
public abstract int countPointsWithinR(double[][] sampleVectors, double r,
boolean allowEqualToR, boolean[] additionalCriteria);
}