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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    *      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.geometry.enclosing.euclidean.threed;
18  
19  import java.util.ArrayList;
20  import java.util.Arrays;
21  import java.util.Collections;
22  import java.util.List;
23  
24  import org.apache.commons.geometry.core.precision.DoublePrecisionContext;
25  import org.apache.commons.geometry.core.precision.EpsilonDoublePrecisionContext;
26  import org.apache.commons.geometry.enclosing.EnclosingBall;
27  import org.apache.commons.geometry.euclidean.threed.Vector3D;
28  import org.apache.commons.rng.UniformRandomProvider;
29  import org.apache.commons.rng.sampling.UnitSphereSampler;
30  import org.apache.commons.rng.simple.RandomSource;
31  import org.junit.Assert;
32  import org.junit.Test;
33  
34  public class SphereGeneratorTest {
35  
36      private static final double TEST_EPS = 1e-10;
37  
38      private static final DoublePrecisionContext TEST_PRECISION =
39              new EpsilonDoublePrecisionContext(TEST_EPS);
40  
41      private final SphereGenerator generator = new SphereGenerator(TEST_PRECISION);
42  
43      @Test
44      public void testSupport0Point() {
45          // arrange
46          final List<Vector3D> support = Collections.emptyList();
47  
48          // act
49          final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
50  
51          // assert
52          Assert.assertTrue(sphere.getRadius() < 0);
53          Assert.assertEquals(0, sphere.getSupportSize());
54          Assert.assertEquals(0, sphere.getSupport().size());
55      }
56  
57      @Test
58      public void testSupport1Point() {
59          // arrange
60          final DoublePrecisionContext lowPrecision = new EpsilonDoublePrecisionContext(0.5);
61          final DoublePrecisionContext highPrecision = new EpsilonDoublePrecisionContext(0.001);
62          final List<Vector3D> support = Collections.singletonList(Vector3D.of(1, 2, 3));
63  
64          // act
65          final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
66  
67          // assert
68          Assert.assertEquals(0.0, sphere.getRadius(), TEST_EPS);
69  
70          Assert.assertTrue(sphere.contains(support.get(0)));
71          Assert.assertTrue(sphere.contains(support.get(0), lowPrecision));
72          Assert.assertFalse(sphere.contains(Vector3D.of(support.get(0).getX() + 0.1,
73                                                          support.get(0).getY() + 0.1,
74                                                          support.get(0).getZ() + 0.1),
75                                              highPrecision));
76          Assert.assertTrue(sphere.contains(Vector3D.of(support.get(0).getX() + 0.1,
77                                                         support.get(0).getY() + 0.1,
78                                                         support.get(0).getZ() + 0.1),
79                                              lowPrecision));
80  
81          Assert.assertEquals(0, support.get(0).distance(sphere.getCenter()), 1.0e-10);
82          Assert.assertEquals(1, sphere.getSupportSize());
83          Assert.assertEquals(support.get(0), sphere.getSupport().get(0));
84      }
85  
86      @Test
87      public void testSupport2Points() {
88          // arrange
89          final List<Vector3D> support = Arrays.asList(Vector3D.of(1, 0, 0),
90                                                 Vector3D.of(3, 0, 0));
91  
92          // act
93          final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
94  
95          // assert
96          Assert.assertEquals(1.0, sphere.getRadius(), TEST_EPS);
97  
98          int i = 0;
99          for (final Vector3D v : support) {
100             Assert.assertTrue(sphere.contains(v));
101             Assert.assertEquals(1.0, v.distance(sphere.getCenter()), TEST_EPS);
102             Assert.assertSame(v, sphere.getSupport().get(i++));
103         }
104 
105         Assert.assertTrue(sphere.contains(Vector3D.of(2, 0.9, 0)));
106         Assert.assertFalse(sphere.contains(Vector3D.ZERO));
107         Assert.assertEquals(0.0, Vector3D.of(2, 0, 0).distance(sphere.getCenter()), TEST_EPS);
108         Assert.assertEquals(2, sphere.getSupportSize());
109     }
110 
111     @Test
112     public void testSupport3Points() {
113         // arrange
114         final List<Vector3D> support = Arrays.asList(Vector3D.of(1, 0, 0),
115                                                Vector3D.of(3, 0, 0),
116                                                Vector3D.of(2, 2, 0));
117 
118         // act
119         final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
120 
121         // assert
122         Assert.assertEquals(5.0 / 4.0, sphere.getRadius(), TEST_EPS);
123 
124         int i = 0;
125         for (final Vector3D v : support) {
126             Assert.assertTrue(sphere.contains(v));
127             Assert.assertEquals(5.0 / 4.0, v.distance(sphere.getCenter()), TEST_EPS);
128             Assert.assertEquals(v, sphere.getSupport().get(i++));
129         }
130 
131         Assert.assertTrue(sphere.contains(Vector3D.of(2, 0.9, 0)));
132         Assert.assertFalse(sphere.contains(Vector3D.of(0.9, 0, 0)));
133         Assert.assertFalse(sphere.contains(Vector3D.of(3.1, 0, 0)));
134         Assert.assertTrue(sphere.contains(Vector3D.of(2.0, -0.499, 0)));
135         Assert.assertFalse(sphere.contains(Vector3D.of(2.0, -0.501, 0)));
136         Assert.assertTrue(sphere.contains(Vector3D.of(2.0, 3.0 / 4.0, -1.249)));
137         Assert.assertFalse(sphere.contains(Vector3D.of(2.0, 3.0 / 4.0, -1.251)));
138         Assert.assertEquals(0.0, Vector3D.of(2.0, 3.0 / 4.0, 0).distance(sphere.getCenter()), TEST_EPS);
139         Assert.assertEquals(3, sphere.getSupportSize());
140     }
141 
142     @Test
143     public void testSupport4Points() {
144         // arrange
145         final List<Vector3D> support = Arrays.asList(Vector3D.of(17, 14, 18),
146                                                Vector3D.of(11, 14, 22),
147                                                Vector3D.of(2, 22, 17),
148                                                Vector3D.of(22, 11, -10));
149 
150         // act
151         final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
152 
153         // assert
154         Assert.assertEquals(25.0, sphere.getRadius(), TEST_EPS);
155 
156         int i = 0;
157         for (final Vector3D v : support) {
158             Assert.assertTrue(sphere.contains(v));
159             Assert.assertEquals(25.0, v.distance(sphere.getCenter()), 1.0e-10);
160             Assert.assertEquals(v, sphere.getSupport().get(i++));
161         }
162 
163         Assert.assertTrue(sphere.contains(Vector3D.of(-22.999, 2, 2)));
164         Assert.assertFalse(sphere.contains(Vector3D.of(-23.001, 2, 2)));
165         Assert.assertTrue(sphere.contains(Vector3D.of(26.999, 2, 2)));
166         Assert.assertFalse(sphere.contains(Vector3D.of(27.001, 2, 2)));
167         Assert.assertTrue(sphere.contains(Vector3D.of(2, -22.999, 2)));
168         Assert.assertFalse(sphere.contains(Vector3D.of(2, -23.001, 2)));
169         Assert.assertTrue(sphere.contains(Vector3D.of(2, 26.999, 2)));
170         Assert.assertFalse(sphere.contains(Vector3D.of(2, 27.001, 2)));
171         Assert.assertTrue(sphere.contains(Vector3D.of(2, 2, -22.999)));
172         Assert.assertFalse(sphere.contains(Vector3D.of(2, 2, -23.001)));
173         Assert.assertTrue(sphere.contains(Vector3D.of(2, 2, 26.999)));
174         Assert.assertFalse(sphere.contains(Vector3D.of(2, 2, 27.001)));
175         Assert.assertEquals(0.0, Vector3D.of(2.0, 2.0, 2.0).distance(sphere.getCenter()), TEST_EPS);
176         Assert.assertEquals(4, sphere.getSupportSize());
177     }
178 
179     @Test
180     public void testRandom() {
181         // arrange
182         final UniformRandomProvider random = RandomSource.create(RandomSource.WELL_1024_A,
183                                                                  0xd015982e9f31ee04L);
184         final UnitSphereSampler sr = new UnitSphereSampler(3, random);
185         for (int i = 0; i < 100; ++i) {
186             final double d = 25 * random.nextDouble();
187             final double refRadius = 10 * random.nextDouble();
188             final Vector3D refCenter = Vector3D.linearCombination(d, Vector3D.of(sr.nextVector()));
189             final List<Vector3D> support = new ArrayList<>();
190             for (int j = 0; j < 5; ++j) {
191                 support.add(Vector3D.linearCombination(1.0, refCenter, refRadius, Vector3D.of(sr.nextVector())));
192             }
193 
194             // act
195             final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
196 
197             // assert
198             Assert.assertEquals(0.0, refCenter.distance(sphere.getCenter()), 4e-7 * refRadius);
199             Assert.assertEquals(refRadius, sphere.getRadius(), 1e-7 * refRadius);
200         }
201     }
202 
203     @Test
204     public void testDegeneratedCase() {
205         // --- arrange
206         final List<Vector3D> support =
207                Arrays.asList(Vector3D.of(Math.scalb(-8039905610797991.0, -50),   //   -7.140870659936730
208                                           Math.scalb(-4663475464714142.0, -48),   //  -16.567993074240455
209                                           Math.scalb(6592658872616184.0, -49)),  //   11.710914678204503
210                              Vector3D.of(Math.scalb(-8036658568968473.0, -50),   //   -7.137986707455888
211                                           Math.scalb(-4664256346424880.0, -48),   //  -16.570767323375720
212                                           Math.scalb(6591357011730307.0, -49)),  //  11.708602108715928)
213                              Vector3D.of(Math.scalb(-8037820142977230.0, -50),   //   -7.139018392423351
214                                           Math.scalb(-4665280434237813.0, -48),   //  -16.574405614157020
215                                           Math.scalb(6592435966112099.0, -49)),  //   11.710518716711425
216                              Vector3D.of(Math.scalb(-8038007803611611.0, -50),   //   -7.139185068549035
217                                           Math.scalb(-4664291215918380.0, -48),   //  -16.570891204702250
218                                           Math.scalb(6595270610894208.0, -49))); //   11.715554057357394
219 
220         // --- act
221         final EnclosingBall<Vector3D> sphere = generator.ballOnSupport(support);
222 
223         // --- assert
224         // the following values have been computed using Emacs calc with exact arithmetic from the
225         // rational representation corresponding to the scalb calls (i.e. -8039905610797991/2^50, ...)
226         // The results were converted to decimal representation rounded to 1.0e-30 when writing the reference
227         // values in this test
228         final double eps = 1e-20;
229         Assert.assertEquals(0.003616820213530053297575846168, sphere.getRadius(), eps);
230         Assert.assertEquals(-7.139325643360503322823511839511, sphere.getCenter().getX(), eps);
231         Assert.assertEquals(-16.571096474251747245361467833760, sphere.getCenter().getY(), eps);
232         Assert.assertEquals(11.711945804096960876521111630800, sphere.getCenter().getZ(), eps);
233 
234         final DoublePrecisionContext supportPrecision = new EpsilonDoublePrecisionContext(1e-14);
235         for (final Vector3D v : support) {
236             Assert.assertTrue(sphere.contains(v, supportPrecision));
237         }
238     }
239 }