From 6c6e06e1c45d79695786a748d7a8643821be80fc Mon Sep 17 00:00:00 2001
From: Vojtech Moravec <vojtech.moravec.st@vsb.cz>
Date: Fri, 4 Sep 2020 10:45:18 +0200
Subject: [PATCH] Finish first implementation of searching in k-DTree.
---
.../java/azgracompress/kdtree/KDNode.java | 29 +++++++++-----
.../java/azgracompress/kdtree/KDTree.java | 39 +++++++++++--------
.../azgracompress/kdtree/TerminalKDNode.java | 10 ++++-
.../quantization/vector/VectorQuantizer.java | 8 ++--
.../java/azgracompress/utilities/Utils.java | 16 ++++++++
5 files changed, 69 insertions(+), 33 deletions(-)
diff --git a/src/main/java/azgracompress/kdtree/KDNode.java b/src/main/java/azgracompress/kdtree/KDNode.java
index c911b54..a6aa6a4 100644
--- a/src/main/java/azgracompress/kdtree/KDNode.java
+++ b/src/main/java/azgracompress/kdtree/KDNode.java
@@ -44,26 +44,34 @@ public class KDNode {
public void findNearestNeighbor(final int[] queryRecord, final KDTree.SearchInfo searchInfo) {
+ if (searchInfo.stopSearching())
+ return;
+
if (isTerminal()) {
- // TODO: Examine records in bucket(node), updating PQD , PQR > ,
((TerminalKDNode) this).findNearestNeighborInBucket(queryRecord, searchInfo);
- if (!ballWithinBounds(queryRecord, searchInfo))
+ if (ballWithinBounds(queryRecord, searchInfo)) {
+ searchInfo.setContinueSearching(false);
return;
+ }
}
- assert (loSon != null && hiSon != null);
+ assert (loSon != null && hiSon != null);
if (queryRecord[discriminator] <= partition) {
double tmp = searchInfo.getUpperBounds()[discriminator];
searchInfo.getUpperBounds()[discriminator] = partition;
loSon.findNearestNeighbor(queryRecord, searchInfo);
searchInfo.getUpperBounds()[discriminator] = tmp;
+
} else {
double tmp = searchInfo.getLowerBounds()[discriminator];
searchInfo.getLowerBounds()[discriminator] = partition;
hiSon.findNearestNeighbor(queryRecord, searchInfo);
searchInfo.getLowerBounds()[discriminator] = tmp;
}
+ if (searchInfo.stopSearching())
+ return;
+
if (queryRecord[discriminator] <= partition) {
double tmp = searchInfo.getLowerBounds()[discriminator];
@@ -80,9 +88,11 @@ public class KDNode {
}
searchInfo.getUpperBounds()[discriminator] = tmp;
}
-
- if (!ballWithinBounds(queryRecord, searchInfo)) {
+ if (searchInfo.stopSearching())
return;
+
+ if (ballWithinBounds(queryRecord, searchInfo)) {
+ searchInfo.setContinueSearching(false);
}
}
@@ -90,17 +100,16 @@ public class KDNode {
return Math.pow((x - y), 2);
}
- private static double dissim(final double value) {
+ private static double dissimilarity(final double value) {
return Math.sqrt(value);
}
- @SuppressWarnings("BooleanMethodIsAlwaysInverted")
private boolean ballWithinBounds(final int[] queryRecord, final KDTree.SearchInfo searchInfo) {
double lbDist, ubDist;
for (int d = 0; d < searchInfo.getDimension(); d++) {
lbDist = coordinateDistance(searchInfo.getLowerBounds()[d], queryRecord[d]);
ubDist = coordinateDistance(searchInfo.getUpperBounds()[d], queryRecord[d]);
- if ((lbDist <= searchInfo.getCurrentClosestDistance()) || (ubDist <= searchInfo.getCurrentClosestDistance())) {
+ if ((lbDist <= searchInfo.getNearestRecordDistance()) || (ubDist <= searchInfo.getNearestRecordDistance())) {
return false;
}
}
@@ -112,12 +121,12 @@ public class KDNode {
for (int d = 0; d < searchInfo.getDimension(); d++) {
if (queryRecord[d] < searchInfo.getLowerBounds()[d]) {
sum += coordinateDistance(queryRecord[d], searchInfo.getLowerBounds()[d]);
- if (dissim(sum) > searchInfo.getCurrentClosestDistance()) {
+ if (dissimilarity(sum) > searchInfo.getNearestRecordDistance()) {
return true;
}
} else if (queryRecord[d] > searchInfo.getUpperBounds()[d]) {
sum += coordinateDistance(queryRecord[d], searchInfo.getUpperBounds()[d]);
- if (dissim(sum) > searchInfo.getCurrentClosestDistance()) {
+ if (dissimilarity(sum) > searchInfo.getNearestRecordDistance()) {
return true;
}
}
diff --git a/src/main/java/azgracompress/kdtree/KDTree.java b/src/main/java/azgracompress/kdtree/KDTree.java
index e97f09b..71e3890 100644
--- a/src/main/java/azgracompress/kdtree/KDTree.java
+++ b/src/main/java/azgracompress/kdtree/KDTree.java
@@ -11,15 +11,16 @@ public class KDTree {
private final int terminalNodeCount;
public static class SearchInfo {
- private double currentClosestDistance;
- private int[] currentClosestRecord = null;
+ private boolean continueSearching = true;
+ private double nearestRecordDistance;
+ private int[] nearestRecord = null;
private final double[] coordinateUpperBound;
private final double[] coordinateLowerBound;
private final int dimension;
public SearchInfo(final int dimension) {
this.dimension = dimension;
- currentClosestDistance = Double.POSITIVE_INFINITY;
+ nearestRecordDistance = Double.POSITIVE_INFINITY;
coordinateUpperBound = new double[dimension];
coordinateLowerBound = new double[dimension];
Arrays.fill(coordinateLowerBound, Double.NEGATIVE_INFINITY);
@@ -30,20 +31,12 @@ public class KDTree {
return dimension;
}
- public double getCurrentClosestDistance() {
- return currentClosestDistance;
+ public double getNearestRecordDistance() {
+ return nearestRecordDistance;
}
- public void setCurrentClosestDistance(double currentClosestDistance) {
- this.currentClosestDistance = currentClosestDistance;
- }
-
- public int[] getCurrentClosestRecord() {
- return currentClosestRecord;
- }
-
- public void setCurrentClosestRecord(int[] currentClosestRecord) {
- this.currentClosestRecord = currentClosestRecord;
+ public int[] getNearestRecord() {
+ return nearestRecord;
}
public double[] getUpperBounds() {
@@ -53,6 +46,19 @@ public class KDTree {
public double[] getLowerBounds() {
return coordinateLowerBound;
}
+
+ public boolean stopSearching() {
+ return !continueSearching;
+ }
+
+ public void setContinueSearching(boolean continueSearching) {
+ this.continueSearching = continueSearching;
+ }
+
+ public void setNearestRecord(final int[] record, final double recordDistance) {
+ this.nearestRecord = record;
+ this.nearestRecordDistance = recordDistance;
+ }
}
public KDTree(final KDNode root,
@@ -68,10 +74,9 @@ public class KDTree {
}
public int[] findNearestNeighbor(final int[] queryRecord) {
- // TODO(Moravec): Read more about Ball Within Bounds and Bounds Overlap Ball
SearchInfo searchInfo = new SearchInfo(dimension);
root.findNearestNeighbor(queryRecord, searchInfo);
- return searchInfo.currentClosestRecord;
+ return searchInfo.nearestRecord;
}
public int getTotalNodeCount() {
diff --git a/src/main/java/azgracompress/kdtree/TerminalKDNode.java b/src/main/java/azgracompress/kdtree/TerminalKDNode.java
index 881ba78..e1425f3 100644
--- a/src/main/java/azgracompress/kdtree/TerminalKDNode.java
+++ b/src/main/java/azgracompress/kdtree/TerminalKDNode.java
@@ -1,5 +1,7 @@
package azgracompress.kdtree;
+import azgracompress.utilities.Utils;
+
public class TerminalKDNode extends KDNode {
private final int[][] bucket;
@@ -19,6 +21,12 @@ public class TerminalKDNode extends KDNode {
}
public void findNearestNeighborInBucket(final int[] queryRecord, final KDTree.SearchInfo searchInfo) {
-
+ double recordDistance;
+ for (final int[] record : bucket) {
+ recordDistance = Utils.calculateEuclideanDistance(queryRecord, record);
+ if (recordDistance < searchInfo.getNearestRecordDistance()) {
+ searchInfo.setNearestRecord(record, recordDistance);
+ }
+ }
}
}
diff --git a/src/main/java/azgracompress/quantization/vector/VectorQuantizer.java b/src/main/java/azgracompress/quantization/vector/VectorQuantizer.java
index 5413e9d..d00696e 100644
--- a/src/main/java/azgracompress/quantization/vector/VectorQuantizer.java
+++ b/src/main/java/azgracompress/quantization/vector/VectorQuantizer.java
@@ -1,5 +1,7 @@
package azgracompress.quantization.vector;
+import azgracompress.utilities.Utils;
+
public class VectorQuantizer {
private final VectorDistanceMetric metric = VectorDistanceMetric.Euclidean;
@@ -104,11 +106,7 @@ public class VectorQuantizer {
return sum;
}
case Euclidean: {
- double sum = 0.0;
- for (int i = 0; i < originalDataVector.length; i++) {
- sum += Math.pow(((double) originalDataVector[i] - (double) codebookEntry[i]), 2);
- }
- return Math.sqrt(sum);
+ return Utils.calculateEuclideanDistance(originalDataVector, codebookEntry);
}
case MaxDiff: {
double maxDiff = Double.MIN_VALUE;
diff --git a/src/main/java/azgracompress/utilities/Utils.java b/src/main/java/azgracompress/utilities/Utils.java
index cf0bc15..7ec9b1e 100644
--- a/src/main/java/azgracompress/utilities/Utils.java
+++ b/src/main/java/azgracompress/utilities/Utils.java
@@ -139,4 +139,20 @@ public class Utils {
final double mse = (sum / (double) difference.length);
return mse;
}
+
+ /**
+ * Calculate the euclidean distance between two vectors.
+ *
+ * @param v1 First vector.
+ * @param v2 Second vector.
+ * @return Euclidean distance.
+ */
+ public static double calculateEuclideanDistance(final int[] v1, final int[] v2) {
+ assert (v1.length == v2.length);
+ double sum = 0.0;
+ for (int i = 0; i < v1.length; i++) {
+ sum += Math.pow(((double) v1[i] - (double) v2[i]), 2);
+ }
+ return Math.sqrt(sum);
+ }
}
\ No newline at end of file
--
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