move kdtree nearestNeighbors perf to test.jts,perf

locationtech · Jan 29, 2025 · 4a8b637 · 4a8b637
1 parent 89ffc84
commit 4a8b637
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Showing 2 changed files with 58 additions and 36 deletions.
diff --git a/modules/core/src/test/java/org/locationtech/jts/index/kdtree/KdTreeTest.java b/modules/core/src/test/java/org/locationtech/jts/index/kdtree/KdTreeTest.java
@@ -160,43 +160,7 @@ public void testNearestNeighbors() {
       }
   }
 
-  public void testNearestNeighborsPerformance() {
-      int n = 1_000_000;
-      int k = 100;
-      KdTree tree = new KdTree();
-      Random rand = new Random(1);
-
-      List<Coordinate> points = new ArrayList<>();
-      for (int i = 0; i < n; i++) {
-          double x = rand.nextDouble();
-          double y = rand.nextDouble();
-          points.add(new Coordinate(x, y));
-      }
-      long startTime = System.nanoTime();
-      for (Coordinate coordinate : points) {
-		tree.insert(coordinate);
-      }
-      long insertTime = System.nanoTime() - startTime;
-      System.out.println("Time to insert " + n + " points: " + (insertTime / 1_000_000) + " ms");
-
-      Coordinate query = new Coordinate(rand.nextDouble(), rand.nextDouble());
-
-      // Time k-NN query using k-d tree
-      startTime = System.nanoTime();
-      List<KdNode> nearest = tree.nearestNeighbors(query, k);
-      long knnTime = System.nanoTime() - startTime;
-      System.out.println("Time to find " + k + " nearest neighbors using k-d tree: " + (knnTime / 1_000_000) + " ms");
 
-      // Time k-NN query using brute-force
-      startTime = System.nanoTime();
-      List<Coordinate> bruteForceNearest = bruteForceNearestNeighbors(tree, query, k);
-      long bruteForceTime = System.nanoTime() - startTime;
-      System.out.println("Time to find " + k + " nearest neighbors using brute-force: " + (bruteForceTime / 1_000_000) + " ms");
-
-      for (int i = 0; i < k; i++) {
-          assertEquals(bruteForceNearest.get(i), nearest.get(i).getCoordinate());
-      }
-  }
 
   public void testCollectNodes() {
       int n = 1000;

diff --git a/modules/core/src/test/java/test/jts/perf/index/KdtreeStressTest.java b/modules/core/src/test/java/test/jts/perf/index/KdtreeStressTest.java
@@ -1,7 +1,15 @@
 package test.jts.perf.index;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.Envelope;
+import org.locationtech.jts.index.kdtree.KdNode;
 import org.locationtech.jts.index.kdtree.KdTree;
 
 /**
@@ -35,6 +43,42 @@ private void run() {
       index.query(env);
     }
     System.out.format("Queries complete\n");
+
+    testNearestNeighborsPerformance();
+  }
+
+  private void testNearestNeighborsPerformance() {
+      int n = 1_000_000;
+      int k = 1000;
+      KdTree tree = new KdTree();
+      Random rand = new Random();
+
+      List<Coordinate> points = new ArrayList<>();
+      for (int i = 0; i < n; i++) {
+          double x = rand.nextDouble();
+          double y = rand.nextDouble();
+          points.add(new Coordinate(x, y));
+      }
+      long startTime = System.nanoTime();
+      for (Coordinate coordinate : points) {
+		tree.insert(coordinate);
+      }
+      long insertTime = System.nanoTime() - startTime;
+      System.out.println("Time to insert " + n + " points: " + (insertTime / 1_000_000) + " ms");
+
+      Coordinate query = new Coordinate(rand.nextDouble(), rand.nextDouble());
+
+      // Time k-NN query using k-d tree
+      startTime = System.nanoTime();
+      List<KdNode> nearest = tree.nearestNeighbors(query, k);
+      long knnTime = System.nanoTime() - startTime;
+      System.out.println("Time to find " + k + " nearest neighbors using k-d tree: " + (knnTime / 1_000_000) + " ms");
+
+      // Time k-NN query using brute-force
+      startTime = System.nanoTime();
+      List<Coordinate> bruteForceNearest = bruteForceNearestNeighbors(tree, query, k);
+      long bruteForceTime = System.nanoTime() - startTime;
+      System.out.println("Time to find " + k + " nearest neighbors using brute-force: " + (bruteForceTime / 1_000_000) + " ms");
   }
 
   /**
@@ -52,4 +96,18 @@ private KdTree createUnbalancedTree(int numPts) {
     }
     return index;
   }
+
+  private List<Coordinate> bruteForceNearestNeighbors(KdTree tree, Coordinate query, int k) {
+      List<Coordinate> allPoints = getAllPoints(tree);
+
+      // Sort all points by distance to the query point
+      allPoints.sort(Comparator.comparingDouble(point -> query.distance(point)));
+
+      // Return the first k points (ordered closest first)
+      return allPoints.subList(0, Math.min(k, allPoints.size()));
+  }
+
+  private List<Coordinate> getAllPoints(KdTree tree) {
+	  return Arrays.stream(KdTree.toCoordinates(tree.getNodes())).collect(Collectors.toList());
+  }
 }