1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math4.legacy.ml.distance;
18
19 import org.junit.Assert;
20 import org.junit.Test;
21 import org.apache.commons.math4.core.jdkmath.JdkMath;
22
23 /**
24 * Tests for {@link EuclideanDistance} class.
25 */
26 public class EuclideanDistanceTest {
27 private final DistanceMeasure distance = new EuclideanDistance();
28
29 @Test
30 public void testZero() {
31 final double[] a = { 0, 1, -2, 3.4, 5, -6.7, 89 };
32 Assert.assertEquals(0, distance.compute(a, a), 0d);
33 }
34
35 @Test
36 public void test() {
37 final double[] a = { 1, -2, 3, 4 };
38 final double[] b = { -5, -6, 7, 8 };
39 final double expected = JdkMath.sqrt(84);
40 Assert.assertEquals(expected, distance.compute(a, b), 0d);
41 Assert.assertEquals(expected, distance.compute(b, a), 0d);
42 }
43 }