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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.enclosing;
23  
24  import org.hipparchus.geometry.euclidean.threed.Euclidean3D;
25  import org.hipparchus.geometry.euclidean.threed.SphereGenerator;
26  import org.hipparchus.geometry.euclidean.threed.Vector3D;
27  import org.hipparchus.random.RandomGenerator;
28  import org.hipparchus.random.UnitSphereRandomVectorGenerator;
29  import org.hipparchus.random.Well1024a;
30  import org.junit.jupiter.api.Test;
31  
32  import java.io.IOException;
33  import java.util.ArrayList;
34  import java.util.Arrays;
35  import java.util.List;
36  
37  import static org.junit.jupiter.api.Assertions.assertEquals;
38  import static org.junit.jupiter.api.Assertions.assertFalse;
39  import static org.junit.jupiter.api.Assertions.assertTrue;
40  
41  
42  class WelzlEncloser3DTest {
43  
44      @Test
45      void testNullList() {
46          SphereGenerator generator = new SphereGenerator();
47          WelzlEncloser<Euclidean3D, Vector3D> encloser =
48                  new WelzlEncloser<Euclidean3D, Vector3D>(1.0e-10, generator);
49          EnclosingBall<Euclidean3D, Vector3D> ball = encloser.enclose(null);
50          assertTrue(ball.getRadius() < 0);
51      }
52  
53      @Test
54      void testNoPoints() {
55          SphereGenerator generator = new SphereGenerator();
56          WelzlEncloser<Euclidean3D, Vector3D> encloser =
57                  new WelzlEncloser<Euclidean3D, Vector3D>(1.0e-10, generator);
58          EnclosingBall<Euclidean3D, Vector3D> ball = encloser.enclose(new ArrayList<Vector3D>());
59          assertTrue(ball.getRadius() < 0);
60      }
61  
62      @Test
63      void testReducingBall() {
64          List<Vector3D> list =
65                  Arrays.asList(new Vector3D(-7.140397329568118, -16.571661242582177,  11.714458961735405),
66                                new Vector3D(-7.137986707455888, -16.570767323375720,  11.708602108715928),
67                                new Vector3D(-7.139185068549035, -16.570891204702250,  11.715554057357394),
68                                new Vector3D(-7.142682716997507, -16.571609818234290,  11.710787934580328),
69                                new Vector3D(-7.139018392423351, -16.574405614157020,  11.710518716711425),
70                                new Vector3D(-7.140870659936730, -16.567993074240455,  11.710914678204503),
71                                new Vector3D(-7.136350173659562, -16.570498228820930,  11.713965225900928),
72                                new Vector3D(-7.141675762759172, -16.572852471407028,  11.714033471449508),
73                                new Vector3D(-7.140453077221105, -16.570212820780647,  11.708624578004980),
74                                new Vector3D(-7.140322188726825, -16.574152894557717,  11.710305611121410),
75                                new Vector3D(-7.141116131477088, -16.574061164624560,  11.712938509321699));
76          WelzlEncloser<Euclidean3D, Vector3D> encloser =
77                  new WelzlEncloser<Euclidean3D, Vector3D>(1.0e-10, new SphereGenerator());
78          EnclosingBall<Euclidean3D, Vector3D> ball = encloser.enclose(list);
79          assertTrue(ball.getRadius() > 0);
80      }
81  
82      @Test
83      void testInfiniteLoop() {
84          // this test used to generate an infinite loop
85          List<Vector3D> list =
86                  Arrays.asList(new Vector3D( -0.89227075512164380,  -2.89317694645713900,  14.84572323743355500),
87                                new Vector3D( -0.92099498940693580,  -2.31086108263908940,  12.92071026467688300),
88                                new Vector3D( -0.85227999411005200,  -3.06314731441320730,  15.40163831651287000),
89                                new Vector3D( -1.77399413020785970,  -3.65630391378114260,  14.13190097751873400),
90                                new Vector3D(  0.33157833272465354,  -2.22813591757792160,  14.21225234159008200),
91                                new Vector3D( -1.53065579165484400,  -1.65692084770139570,  14.61483055714788500),
92                                new Vector3D( -1.08457093941217140,  -1.96100325935602980,  13.09265170575555000),
93                                new Vector3D(  0.30029469589708850,  -3.05470831395667370,  14.56352400426342600),
94                                new Vector3D( -0.95007443938638460,  -1.86810946486118360,  15.14491234340057000),
95                                new Vector3D( -1.89661503804130830,  -2.17004080885185860,  14.81235128513927000),
96                                new Vector3D( -0.72193328761607530,  -1.44513142833618270,  14.52355724218561800),
97                                new Vector3D( -0.26895980939606550,  -3.69512371522084140,  14.72272846327652000),
98                                new Vector3D( -1.53501693431786170,  -3.25055166611021900,  15.15509062584274800),
99                                new Vector3D( -0.71727553535519410,  -3.62284279460799100,  13.26256700929380700),
100                               new Vector3D( -0.30220950676137365,  -3.25410412500779070,  13.13682612771606000),
101                               new Vector3D( -0.04543996608267075,  -1.93081853923797750,  14.79497997883171400),
102                               new Vector3D( -1.53348892951571640,  -3.66688919703524900,  14.73095600812074200),
103                               new Vector3D( -0.98034899533935820,  -3.34004481162763960,  13.03245014017556800));
104 
105         WelzlEncloser<Euclidean3D, Vector3D> encloser =
106                 new WelzlEncloser<Euclidean3D, Vector3D>(1.0e-10, new SphereGenerator());
107         EnclosingBall<Euclidean3D, Vector3D> ball = encloser.enclose(list);
108         assertTrue(ball.getRadius() > 0);
109     }
110 
111     @Test
112     void testLargeSamples() throws IOException {
113         RandomGenerator random = new Well1024a(0x35ddecfc78131e1dl);
114         final UnitSphereRandomVectorGenerator sr = new UnitSphereRandomVectorGenerator(3, random);
115         for (int k = 0; k < 50; ++k) {
116 
117             // define the reference sphere we want to compute
118             double d = 25 * random.nextDouble();
119             double refRadius = 10 * random.nextDouble();
120             Vector3D refCenter = new Vector3D(d, new Vector3D(sr.nextVector()));
121             // set up a large sample inside the reference sphere
122             int nbPoints = random.nextInt(1000);
123             List<Vector3D> points = new ArrayList<Vector3D>();
124             for (int i = 0; i < nbPoints; ++i) {
125                 double r = refRadius * random.nextDouble();
126                 points.add(new Vector3D(1.0, refCenter, r, new Vector3D(sr.nextVector())));
127             }
128 
129             // test we find a sphere at most as large as the one used for random drawings
130             checkSphere(points, refRadius);
131 
132         }
133     }
134 
135     @Test
136     void testIssue20Generator() {
137 
138         final SupportBallGenerator<Euclidean3D, Vector3D> generator = new SphereGenerator();
139         final Vector3D p1 = new Vector3D(0.9987716667, 0.0350821284, 0.0349914572);
140         final Vector3D p2 = new Vector3D(0.9987856181, -0.0346743952, 0.0349996489);
141         final Vector3D p4 = new Vector3D(0.9987798601, 0.0350739383, -0.0347650673);
142         EnclosingBall<Euclidean3D, Vector3D> s24  = generator.ballOnSupport(Arrays.asList(p2, p4));
143         EnclosingBall<Euclidean3D, Vector3D> s142 = generator.ballOnSupport(Arrays.asList(p1, p4, p2));
144 
145         assertFalse(s24.contains(p1));
146         assertTrue(s24.contains(p2));
147         assertTrue(s24.contains(p4));
148 
149         assertTrue(s142.contains(p1));
150         assertTrue(s142.contains(p4));
151         assertTrue(s142.contains(p2));
152 
153         assertTrue(s142.getRadius() >= s24.getRadius());
154 
155     }
156 
157     @Test
158     void testIssue20Encloser() {
159         final WelzlEncloser<Euclidean3D, Vector3D> encloser =
160                         new WelzlEncloser<Euclidean3D, Vector3D>(1e-14, new SphereGenerator());
161         List<Vector3D> points = new ArrayList<Vector3D>();
162         points.add(new Vector3D(0.9999999731, 0.000200015, 0.0001174338));
163         points.add(new Vector3D(0.9987716667, 0.0350821284, 0.0349914572));
164         points.add(new Vector3D(0.9987856181, -0.0346743952, 0.0349996489));
165         points.add(new Vector3D(0.9987938115, -0.0346825853, -0.0347568755));
166         points.add(new Vector3D(0.9987798601, 0.0350739383, -0.0347650673));
167         EnclosingBall<Euclidean3D, Vector3D> enclosing3D = encloser.enclose(points);
168         assertEquals(0.04932531217754311, enclosing3D.getRadius(), 1.0e-15);
169         for (final Vector3D p : points) {
170             assertTrue(enclosing3D.contains(p));
171         }
172     }
173 
174     private void checkSphere(List<Vector3D> points, double refRadius) {
175 
176         EnclosingBall<Euclidean3D, Vector3D> sphere = checkSphere(points);
177 
178         // compare computed sphere with bounding sphere
179         assertTrue(sphere.getRadius() <= refRadius);
180 
181         // check removing any point of the support Sphere fails to enclose the point
182         for (int i = 0; i < sphere.getSupportSize(); ++i) {
183             List<Vector3D> reducedSupport = new ArrayList<Vector3D>();
184             int count = 0;
185             for (Vector3D s : sphere.getSupport()) {
186                 if (count++ != i) {
187                     reducedSupport.add(s);
188                 }
189             }
190             EnclosingBall<Euclidean3D, Vector3D> reducedSphere =
191                     new SphereGenerator().ballOnSupport(reducedSupport);
192             boolean foundOutside = false;
193             for (int j = 0; j < points.size() && !foundOutside; ++j) {
194                 if (!reducedSphere.contains(points.get(j), 1.0e-10)) {
195                     foundOutside = true;
196                 }
197             }
198             assertTrue(foundOutside);
199         }
200 
201     }
202 
203     private EnclosingBall<Euclidean3D, Vector3D> checkSphere(List<Vector3D> points) {
204 
205         WelzlEncloser<Euclidean3D, Vector3D> encloser =
206                 new WelzlEncloser<Euclidean3D, Vector3D>(1.0e-10, new SphereGenerator());
207         EnclosingBall<Euclidean3D, Vector3D> Sphere = encloser.enclose(points);
208 
209         // all points are enclosed
210         for (Vector3D v : points) {
211             assertTrue(Sphere.contains(v, 1.0e-10));
212         }
213 
214         for (Vector3D v : points) {
215             boolean inSupport = false;
216             for (Vector3D s : Sphere.getSupport()) {
217                 if (v == s) {
218                     inSupport = true;
219                 }
220             }
221             if (inSupport) {
222                 // points on the support should be outside of reduced ball
223                 assertFalse(Sphere.contains(v, -0.001));
224             }
225         }
226 
227         return Sphere;
228 
229     }
230 
231 }