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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.geometry.euclidean.twod;
23  
24  import org.hipparchus.geometry.enclosing.EnclosingBall;
25  import org.hipparchus.random.RandomGenerator;
26  import org.hipparchus.random.UnitSphereRandomVectorGenerator;
27  import org.hipparchus.random.Well1024a;
28  import org.junit.jupiter.api.Test;
29  
30  import java.util.ArrayList;
31  import java.util.Arrays;
32  import java.util.List;
33  
34  import static org.junit.jupiter.api.Assertions.assertEquals;
35  import static org.junit.jupiter.api.Assertions.assertFalse;
36  import static org.junit.jupiter.api.Assertions.assertTrue;
37  
38  
39  class DiskGeneratorTest {
40  
41      @Test
42      void testSupport0Point() {
43          List<Vector2D> support = Arrays.asList(new Vector2D[0]);
44          EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
45          assertTrue(disk.getRadius() < 0);
46          assertEquals(0, disk.getSupportSize());
47          assertEquals(0, disk.getSupport().length);
48      }
49  
50      @Test
51      void testSupport1Point() {
52          List<Vector2D> support = Arrays.asList(new Vector2D(1, 2));
53          EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
54          assertEquals(0.0, disk.getRadius(), 1.0e-10);
55          assertTrue(disk.contains(support.get(0)));
56          assertTrue(disk.contains(support.get(0), 0.5));
57          assertFalse(disk.contains(new Vector2D(support.get(0).getX() + 0.1,
58                                                        support.get(0).getY() - 0.1),
59                                           0.001));
60          assertTrue(disk.contains(new Vector2D(support.get(0).getX() + 0.1,
61                                                       support.get(0).getY() - 0.1),
62                                          0.5));
63          assertEquals(0, support.get(0).distance(disk.getCenter()), 1.0e-10);
64          assertEquals(1, disk.getSupportSize());
65          assertTrue(support.get(0) == disk.getSupport()[0]);
66      }
67  
68      @Test
69      void testSupport2Points() {
70          List<Vector2D> support = Arrays.asList(new Vector2D(1, 0),
71                                                 new Vector2D(3, 0));
72          EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
73          assertEquals(1.0, disk.getRadius(), 1.0e-10);
74          int i = 0;
75          for (Vector2D v : support) {
76              assertTrue(disk.contains(v));
77              assertEquals(1.0, v.distance(disk.getCenter()), 1.0e-10);
78              assertTrue(v == disk.getSupport()[i++]);
79          }
80          assertTrue(disk.contains(new Vector2D(2, 0.9)));
81          assertFalse(disk.contains(Vector2D.ZERO));
82          assertEquals(0.0, new Vector2D(2, 0).distance(disk.getCenter()), 1.0e-10);
83          assertEquals(2, disk.getSupportSize());
84      }
85  
86      @Test
87      void testSupport3Points() {
88          List<Vector2D> support = Arrays.asList(new Vector2D(1, 0),
89                                                 new Vector2D(3, 0),
90                                                 new Vector2D(2, 2));
91          EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
92          assertEquals(5.0 / 4.0, disk.getRadius(), 1.0e-10);
93          int i = 0;
94          for (Vector2D v : support) {
95              assertTrue(disk.contains(v));
96              assertEquals(5.0 / 4.0, v.distance(disk.getCenter()), 1.0e-10);
97              assertTrue(v == disk.getSupport()[i++]);
98          }
99          assertTrue(disk.contains(new Vector2D(2, 0.9)));
100         assertFalse(disk.contains(new Vector2D(0.9,  0)));
101         assertFalse(disk.contains(new Vector2D(3.1,  0)));
102         assertTrue(disk.contains(new Vector2D(2.0, -0.499)));
103         assertFalse(disk.contains(new Vector2D(2.0, -0.501)));
104         assertEquals(0.0, new Vector2D(2.0, 3.0 / 4.0).distance(disk.getCenter()), 1.0e-10);
105         assertEquals(3, disk.getSupportSize());
106     }
107 
108     @Test
109     void testRandom() {
110         final RandomGenerator random = new Well1024a(0x12faa818373ffe90l);
111         final UnitSphereRandomVectorGenerator sr = new UnitSphereRandomVectorGenerator(2, random);
112         for (int i = 0; i < 500; ++i) {
113             double d = 25 * random.nextDouble();
114             double refRadius = 10 * random.nextDouble();
115             Vector2D refCenter = new Vector2D(d, new Vector2D(sr.nextVector()));
116             List<Vector2D> support = new ArrayList<Vector2D>();
117             for (int j = 0; j < 3; ++j) {
118                 support.add(new Vector2D(1.0, refCenter, refRadius, new Vector2D(sr.nextVector())));
119             }
120             EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
121             assertEquals(0.0, refCenter.distance(disk.getCenter()), 3e-9 * refRadius);
122             assertEquals(refRadius, disk.getRadius(), 7e-10 * refRadius);
123         }
124 
125     }
126 }