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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    *      https://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  
18  /*
19   * This is not the original file distributed by the Apache Software Foundation
20   * It has been modified by the Hipparchus project
21   */
22  package org.hipparchus.clustering.distance;
23  
24  import org.junit.Assert;
25  import org.junit.Test;
26  
27  /**
28   * Tests for {@link EarthMoversDistance} class.
29   */
30  public class EarthMoversDistanceTest {
31  
32      final DistanceMeasure distance = new EarthMoversDistance();
33      final double[] a = { 0.1, 0.3, 0.2, 0.0, 0.25, 0.15 };
34      final double[] b = { 0.3, 0.0, 0.4, 0.1, 0.0, 0.2 };
35  
36      @Test
37      public void testZero() {
38          Assert.assertEquals(0, distance.compute(a, a), 0d);
39      }
40  
41      @Test
42      public void testZero2() {
43          final double[] zero = new double[] { 0, 0 };
44          Assert.assertEquals(0, distance.compute(zero, zero), 0d);
45      }
46  
47      @Test
48      public void test() {
49          double expected = 0.65; //0.2 + 0.1 + 0.1 + 0.2 + 0.05 + 0.0;
50          Assert.assertEquals(expected, distance.compute(a, b), 1e-10);
51          Assert.assertEquals(expected, distance.compute(b, a), 1e-10);
52      }
53  }