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Java example source code file (DBSCANClustererTest.java)

This example Java source code file (DBSCANClustererTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

dbscanclusterer, dbscanclusterertest, doublepoint, list, noise, test, util

The DBSCANClustererTest.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math3.ml.clustering;

import java.util.Arrays;
import java.util.List;

import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.junit.Assert;
import org.junit.Test;

public class DBSCANClustererTest {

    @Test
    public void testCluster() {
        // Test data generated using: http://people.cs.nctu.edu.tw/~rsliang/dbscan/testdatagen.html
        final DoublePoint[] points = new DoublePoint[] {
                new DoublePoint(new double[] { 83.08303244924173, 58.83387754182331 }),
                new DoublePoint(new double[] { 45.05445510940626, 23.469642649637535 }),
                new DoublePoint(new double[] { 14.96417921432294, 69.0264096390456 }),
                new DoublePoint(new double[] { 73.53189604333602, 34.896145021310076 }),
                new DoublePoint(new double[] { 73.28498173551634, 33.96860806993209 }),
                new DoublePoint(new double[] { 73.45828098873608, 33.92584423092194 }),
                new DoublePoint(new double[] { 73.9657889183145, 35.73191006924026 }),
                new DoublePoint(new double[] { 74.0074097183533, 36.81735596177168 }),
                new DoublePoint(new double[] { 73.41247541410848, 34.27314856695011 }),
                new DoublePoint(new double[] { 73.9156256353017, 36.83206791547127 }),
                new DoublePoint(new double[] { 74.81499205809087, 37.15682749846019 }),
                new DoublePoint(new double[] { 74.03144880081527, 37.57399178552441 }),
                new DoublePoint(new double[] { 74.51870941207744, 38.674258946906775 }),
                new DoublePoint(new double[] { 74.50754595105536, 35.58903978415765 }),
                new DoublePoint(new double[] { 74.51322752749547, 36.030572259100154 }),
                new DoublePoint(new double[] { 59.27900996617973, 46.41091720294207 }),
                new DoublePoint(new double[] { 59.73744793841615, 46.20015558367595 }),
                new DoublePoint(new double[] { 58.81134076672606, 45.71150126331486 }),
                new DoublePoint(new double[] { 58.52225539437495, 47.416083617601544 }),
                new DoublePoint(new double[] { 58.218626647023484, 47.36228902172297 }),
                new DoublePoint(new double[] { 60.27139669447206, 46.606106348801404 }),
                new DoublePoint(new double[] { 60.894962462363765, 46.976924697402865 }),
                new DoublePoint(new double[] { 62.29048673878424, 47.66970563563518 }),
                new DoublePoint(new double[] { 61.03857608977705, 46.212924720020965 }),
                new DoublePoint(new double[] { 60.16916214139201, 45.18193661351688 }),
                new DoublePoint(new double[] { 59.90036905976012, 47.555364347063005 }),
                new DoublePoint(new double[] { 62.33003634144552, 47.83941489877179 }),
                new DoublePoint(new double[] { 57.86035536718555, 47.31117930193432 }),
                new DoublePoint(new double[] { 58.13715479685925, 48.985960494028404 }),
                new DoublePoint(new double[] { 56.131923963548616, 46.8508904252667 }),
                new DoublePoint(new double[] { 55.976329887053, 47.46384037658572 }),
                new DoublePoint(new double[] { 56.23245975235477, 47.940035191131756 }),
                new DoublePoint(new double[] { 58.51687048212625, 46.622885352699086 }),
                new DoublePoint(new double[] { 57.85411081905477, 45.95394361577928 }),
                new DoublePoint(new double[] { 56.445776311447844, 45.162093662656844 }),
                new DoublePoint(new double[] { 57.36691949656233, 47.50097194337286 }),
                new DoublePoint(new double[] { 58.243626387557015, 46.114052729681134 }),
                new DoublePoint(new double[] { 56.27224595635198, 44.799080066150054 }),
                new DoublePoint(new double[] { 57.606924816500396, 46.94291057763621 }),
                new DoublePoint(new double[] { 30.18714230041951, 13.877149710431695 }),
                new DoublePoint(new double[] { 30.449448810657486, 13.490778346545994 }),
                new DoublePoint(new double[] { 30.295018390286714, 13.264889000216499 }),
                new DoublePoint(new double[] { 30.160201832884923, 11.89278262341395 }),
                new DoublePoint(new double[] { 31.341509791789576, 15.282655921997502 }),
                new DoublePoint(new double[] { 31.68601630325429, 14.756873246748 }),
                new DoublePoint(new double[] { 29.325963742565364, 12.097849250072613 }),
                new DoublePoint(new double[] { 29.54820742388256, 13.613295356975868 }),
                new DoublePoint(new double[] { 28.79359608888626, 10.36352064087987 }),
                new DoublePoint(new double[] { 31.01284597092308, 12.788479208014905 }),
                new DoublePoint(new double[] { 27.58509216737002, 11.47570110601373 }),
                new DoublePoint(new double[] { 28.593799561727792, 10.780998203903437 }),
                new DoublePoint(new double[] { 31.356105766724795, 15.080316198524088 }),
                new DoublePoint(new double[] { 31.25948503636755, 13.674329151166603 }),
                new DoublePoint(new double[] { 32.31590076372959, 14.95261758659035 }),
                new DoublePoint(new double[] { 30.460413702763617, 15.88402809202671 }),
                new DoublePoint(new double[] { 32.56178203062154, 14.586076852632686 }),
                new DoublePoint(new double[] { 32.76138648530468, 16.239837325178087 }),
                new DoublePoint(new double[] { 30.1829453331884, 14.709592407103628 }),
                new DoublePoint(new double[] { 29.55088173528202, 15.0651247180067 }),
                new DoublePoint(new double[] { 29.004155302187428, 14.089665298582986 }),
                new DoublePoint(new double[] { 29.339624439831823, 13.29096065578051 }),
                new DoublePoint(new double[] { 30.997460327576846, 14.551914158277214 }),
                new DoublePoint(new double[] { 30.66784126125276, 16.269703107886016 })
        };

        final DBSCANClusterer<DoublePoint> transformer =
                new DBSCANClusterer<DoublePoint>(2.0, 5);
        final List<Cluster clusters = transformer.cluster(Arrays.asList(points));

        final List<DoublePoint> clusterOne =
                Arrays.asList(points[3], points[4], points[5], points[6], points[7], points[8], points[9], points[10],
                              points[11], points[12], points[13], points[14]);
        final List<DoublePoint> clusterTwo =
                Arrays.asList(points[15], points[16], points[17], points[18], points[19], points[20], points[21],
                              points[22], points[23], points[24], points[25], points[26], points[27], points[28],
                              points[29], points[30], points[31], points[32], points[33], points[34], points[35],
                              points[36], points[37], points[38]);
        final List<DoublePoint> clusterThree =
                Arrays.asList(points[39], points[40], points[41], points[42], points[43], points[44], points[45],
                              points[46], points[47], points[48], points[49], points[50], points[51], points[52],
                              points[53], points[54], points[55], points[56], points[57], points[58], points[59],
                              points[60], points[61], points[62]);

        boolean cluster1Found = false;
        boolean cluster2Found = false;
        boolean cluster3Found = false;
        Assert.assertEquals(3, clusters.size());
        for (final Cluster<DoublePoint> cluster : clusters) {
            if (cluster.getPoints().containsAll(clusterOne)) {
                cluster1Found = true;
            }
            if (cluster.getPoints().containsAll(clusterTwo)) {
                cluster2Found = true;
            }
            if (cluster.getPoints().containsAll(clusterThree)) {
                cluster3Found = true;
            }
        }
        Assert.assertTrue(cluster1Found);
        Assert.assertTrue(cluster2Found);
        Assert.assertTrue(cluster3Found);
    }

    @Test
    public void testSingleLink() {
        final DoublePoint[] points = {
                new DoublePoint(new int[] {10, 10}), // A
                new DoublePoint(new int[] {12, 9}),
                new DoublePoint(new int[] {10, 8}),
                new DoublePoint(new int[] {8, 8}),
                new DoublePoint(new int[] {8, 6}),
                new DoublePoint(new int[] {7, 7}),
                new DoublePoint(new int[] {5, 6}),  // B
                new DoublePoint(new int[] {14, 8}), // C
                new DoublePoint(new int[] {7, 15}), // N - Noise, should not be present
                new DoublePoint(new int[] {17, 8}), // D - single-link connected to C should not be present

        };

        final DBSCANClusterer<DoublePoint> clusterer = new DBSCANClusterer(3, 3);
        List<Cluster clusters = clusterer.cluster(Arrays.asList(points));

        Assert.assertEquals(1, clusters.size());

        final List<DoublePoint> clusterOne =
                Arrays.asList(points[0], points[1], points[2], points[3], points[4], points[5], points[6], points[7]);
        Assert.assertTrue(clusters.get(0).getPoints().containsAll(clusterOne));
    }

    @Test
    public void testGetEps() {
        final DBSCANClusterer<DoublePoint> transformer = new DBSCANClusterer(2.0, 5);
        Assert.assertEquals(2.0, transformer.getEps(), 0.0);
    }

    @Test
    public void testGetMinPts() {
        final DBSCANClusterer<DoublePoint> transformer = new DBSCANClusterer(2.0, 5);
        Assert.assertEquals(5, transformer.getMinPts());
    }

    @Test(expected = MathIllegalArgumentException.class)
    public void testNegativeEps() {
        new DBSCANClusterer<DoublePoint>(-2.0, 5);
    }

    @Test(expected = MathIllegalArgumentException.class)
    public void testNegativeMinPts() {
        new DBSCANClusterer<DoublePoint>(2.0, -5);
    }

    @Test(expected = NullArgumentException.class)
    public void testNullDataset() {
        DBSCANClusterer<DoublePoint> clusterer = new DBSCANClusterer(2.0, 5);
        clusterer.cluster(null);
    }

}

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