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89 lines
2.7 KiB
Java
89 lines
2.7 KiB
Java
import java.util.*;
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public class CoverTreeTest {
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public static void main(String[] args) {
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test();
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perfomance();
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}
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static void test() {
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Random rnd = new Random(1);
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for (int step = 0; step < 10000; step++) {
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int n = rnd.nextInt(100) + 2;
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long[] x = new long[n];
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long[] y = new long[n];
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CoverTree.Node[] nodes = new CoverTree.Node[n];
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Set<Long> set = new HashSet<>();
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CoverTree tree = new CoverTree();
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for (int i = 0; i < n; i++) {
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do {
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x[i] = rnd.nextInt(100000);
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y[i] = rnd.nextInt(100000);
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} while (!set.add((x[i] << 30) + y[i]));
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nodes[i] = new CoverTree.Node(x[i], y[i]);
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}
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for (int i = 0; i < n; i++)
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tree.insert(nodes[i]);
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double[] dist2 = new double[n];
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for (int i = 0; i < n; i++) {
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CoverTree.Node p = tree.findNearest(nodes[i]);
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dist2[i] = CoverTree.dist(p, nodes[i]);
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}
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double[] dist1 = new double[n];
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Arrays.fill(dist1, Double.POSITIVE_INFINITY);
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < n; j++)
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if (i != j)
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dist1[i] = Math.min(dist1[i], (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]));
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dist1[i] = Math.sqrt(dist1[i]);
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}
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if (!Arrays.equals(dist1, dist2)) {
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System.err.println(Arrays.toString(dist1));
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System.err.println(Arrays.toString(dist2));
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}
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}
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}
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static void perfomance() {
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Random rnd = new Random(1);
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int n = 100000;
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long[] x = new long[n];
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long[] y = new long[n];
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CoverTree.Node[] nodes = new CoverTree.Node[n];
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Set<Long> set = new HashSet<>();
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CoverTree tree = new CoverTree();
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for (int i = 0; i < n; i++) {
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do {
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x[i] = rnd.nextInt(100000);
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y[i] = rnd.nextInt(100000);
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} while (!set.add((x[i] << 30) + y[i]));
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nodes[i] = new CoverTree.Node(x[i], y[i]);
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}
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long time = System.currentTimeMillis();
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for (int i = 0; i < n; i++)
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tree.insert(nodes[i]);
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System.out.println("build time: " + (System.currentTimeMillis() - time));
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double[] dist2 = new double[n];
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time = System.currentTimeMillis();
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for (int i = 0; i < n; i++) {
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CoverTree.Node p = tree.findNearest(nodes[i]);
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dist2[i] = CoverTree.dist(p, nodes[i]);
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}
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System.out.println("search time:" + (System.currentTimeMillis() - time));
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double[] dist1 = new double[n];
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Arrays.fill(dist1, Double.POSITIVE_INFINITY);
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time = System.currentTimeMillis();
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < n; j++)
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if (i != j)
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dist1[i] = Math.min(dist1[i], (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]));
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dist1[i] = Math.sqrt(dist1[i]);
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}
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System.out.println("brute force time: " + (System.currentTimeMillis() - time));
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System.out.println(Arrays.equals(dist1, dist2));
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// System.out.println(Arrays.toString(dist1));
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// System.out.println(Arrays.toString(dist2));
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}
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}
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