CoverTreeTest.java

/*******************************************************************************
 * Copyright (c) 2010 Haifeng Li
 *   
 * Licensed 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 smile.neighbor;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import smile.math.distance.EuclideanDistance;
import static org.junit.Assert.*;

/**
 *
 * @author Haifeng Li
 */
@SuppressWarnings("rawtypes")
public class CoverTreeTest {
    double[][] data = null;
    CoverTree<double[]> coverTree = null;
    LinearSearch<double[]> naive = null;

    public CoverTreeTest() {
        data = new double[1000][];
        for (int i = 0; i < data.length; i++) {
            data[i] = new double[10];
            for (int j = 0; j < data[i].length; j++)
                data[i][j] = Math.random();
        }

        coverTree = new CoverTree<>(data, new EuclideanDistance());
        naive = new LinearSearch<>(data, new EuclideanDistance());
    }


    @BeforeClass
    public static void setUpClass() throws Exception {
    }

    @AfterClass
    public static void tearDownClass() throws Exception {
    }

    @Before
    public void setUp() {
    }

    @After
    public void tearDown() {
    }


    /**
     * Test of nearest method, of class CoverTree.
     */
    @Test
    public void testNearest() {
        System.out.println("nearest");
        for (int i = 0; i < data.length; i++) {
            Neighbor n1 = coverTree.nearest(data[i]);
            Neighbor n2 = naive.nearest(data[i]);
            assertEquals(n1.index, n2.index);
            assertEquals(n1.value, n2.value);
            assertEquals(n1.distance, n2.distance, 1E-7);
        }
    }

    /**
     * Test of knn method, of class CoverTree.
     */
    @Test
    public void testKnn() {
        System.out.println("knn");
        for (int i = 0; i < data.length; i++) {
            Neighbor[] n1 = coverTree.knn(data[i], 10);
            Neighbor[] n2 = naive.knn(data[i], 10);
            assertEquals(n1.length, n2.length);
            for (int j = 0; j < n1.length; j++) {
                assertEquals(n1[j].index, n2[j].index);
                assertEquals(n1[j].value, n2[j].value);
                assertEquals(n1[j].distance, n2[j].distance, 1E-7);
            }
        }
    }

    /**
     * Test of knn method, of class CoverTree. The data has only one elements
     */
    @Test
    public void testKnn1() {
        System.out.println("knn1");
        double[][] data1 = {data[0]};
        EuclideanDistance d = new EuclideanDistance();
        coverTree = new CoverTree<>(data1, d);
        Neighbor[] n1 = coverTree.knn(data[1], 1);
        assertEquals(1, n1.length);
        assertEquals(0, n1[0].index);
        assertEquals(data[0], n1[0].value);
        assertEquals(d.d(data[0], data[1]), n1[0].distance, 1E-7);
    }

    /**
     * Test of range method, of class CoverTree.
     */
    @Test
    public void testRange() {
        System.out.println("range");
        List<Neighbor<double[], double[]>> n1 = new ArrayList<>();
        List<Neighbor<double[], double[]>> n2 = new ArrayList<>();
        for (int i = 0; i < data.length; i++) {
            coverTree.range(data[i], 0.5, n1);
            naive.range(data[i], 0.5, n2);
            Collections.sort(n1);
            Collections.sort(n2);
            assertEquals(n1.size(), n2.size());
            for (int j = 0; j < n1.size(); j++) {
                assertEquals(n1.get(j).index, n2.get(j).index);
                assertEquals(n1.get(j).value, n2.get(j).value);
                assertEquals(n1.get(j).distance, n2.get(j).distance, 1E-7);
            }
            n1.clear();
            n2.clear();
        }
    }
}