Java example source code file (SphereGeneratorTest.java)

This example Java source code file (SphereGeneratorTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, enclosingball, list, randomgenerator, spheregeneratortest, test, unitsphererandomvectorgenerator, util, vector3d, well1024a

The SphereGeneratorTest.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math3.geometry.euclidean.threed;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.commons.math3.geometry.enclosing.EnclosingBall;
import org.apache.commons.math3.random.RandomGenerator;
import org.apache.commons.math3.random.UnitSphereRandomVectorGenerator;
import org.apache.commons.math3.random.Well1024a;
import org.apache.commons.math3.util.FastMath;
import org.junit.Assert;
import org.junit.Test;


public class SphereGeneratorTest {

    @Test
    public void testSupport0Point() {
        List<Vector3D> support = Arrays.asList(new Vector3D[0]);
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
        Assert.assertTrue(sphere.getRadius() < 0);
        Assert.assertEquals(0, sphere.getSupportSize());
        Assert.assertEquals(0, sphere.getSupport().length);
    }

    @Test
    public void testSupport1Point() {
        List<Vector3D> support = Arrays.asList(new Vector3D(1, 2, 3));
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
        Assert.assertEquals(0.0, sphere.getRadius(), 1.0e-10);
        Assert.assertTrue(sphere.contains(support.get(0)));
        Assert.assertTrue(sphere.contains(support.get(0), 0.5));
        Assert.assertFalse(sphere.contains(new Vector3D(support.get(0).getX() + 0.1,
                                                        support.get(0).getY() + 0.1,
                                                        support.get(0).getZ() + 0.1),
                                           0.001));
        Assert.assertTrue(sphere.contains(new Vector3D(support.get(0).getX() + 0.1,
                                                       support.get(0).getY() + 0.1,
                                                       support.get(0).getZ() + 0.1),
                                          0.5));
        Assert.assertEquals(0, support.get(0).distance(sphere.getCenter()), 1.0e-10);
        Assert.assertEquals(1, sphere.getSupportSize());
        Assert.assertTrue(support.get(0) == sphere.getSupport()[0]);
    }

    @Test
    public void testSupport2Points() {
        List<Vector3D> support = Arrays.asList(new Vector3D(1, 0, 0),
                                               new Vector3D(3, 0, 0));
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
        Assert.assertEquals(1.0, sphere.getRadius(), 1.0e-10);
        int i = 0;
        for (Vector3D v : support) {
            Assert.assertTrue(sphere.contains(v));
            Assert.assertEquals(1.0, v.distance(sphere.getCenter()), 1.0e-10);
            Assert.assertTrue(v == sphere.getSupport()[i++]);
        }
        Assert.assertTrue(sphere.contains(new Vector3D(2, 0.9, 0)));
        Assert.assertFalse(sphere.contains(Vector3D.ZERO));
        Assert.assertEquals(0.0, new Vector3D(2, 0, 0).distance(sphere.getCenter()), 1.0e-10);
        Assert.assertEquals(2, sphere.getSupportSize());
    }

    @Test
    public void testSupport3Points() {
        List<Vector3D> support = Arrays.asList(new Vector3D(1, 0, 0),
                                               new Vector3D(3, 0, 0),
                                               new Vector3D(2, 2, 0));
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
        Assert.assertEquals(5.0 / 4.0, sphere.getRadius(), 1.0e-10);
        int i = 0;
        for (Vector3D v : support) {
            Assert.assertTrue(sphere.contains(v));
            Assert.assertEquals(5.0 / 4.0, v.distance(sphere.getCenter()), 1.0e-10);
            Assert.assertTrue(v == sphere.getSupport()[i++]);
        }
        Assert.assertTrue(sphere.contains(new Vector3D(2, 0.9, 0)));
        Assert.assertFalse(sphere.contains(new Vector3D(0.9,  0, 0)));
        Assert.assertFalse(sphere.contains(new Vector3D(3.1,  0, 0)));
        Assert.assertTrue(sphere.contains(new Vector3D(2.0, -0.499, 0)));
        Assert.assertFalse(sphere.contains(new Vector3D(2.0, -0.501, 0)));
        Assert.assertTrue(sphere.contains(new Vector3D(2.0, 3.0 / 4.0, -1.249)));
        Assert.assertFalse(sphere.contains(new Vector3D(2.0, 3.0 / 4.0, -1.251)));
        Assert.assertEquals(0.0, new Vector3D(2.0, 3.0 / 4.0, 0).distance(sphere.getCenter()), 1.0e-10);
        Assert.assertEquals(3, sphere.getSupportSize());
    }

    @Test
    public void testSupport4Points() {
        List<Vector3D> support = Arrays.asList(new Vector3D(17, 14,  18),
                                               new Vector3D(11, 14,  22),
                                               new Vector3D( 2, 22,  17),
                                               new Vector3D(22, 11, -10));
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
        Assert.assertEquals(25.0, sphere.getRadius(), 1.0e-10);
        int i = 0;
        for (Vector3D v : support) {
            Assert.assertTrue(sphere.contains(v));
            Assert.assertEquals(25.0, v.distance(sphere.getCenter()), 1.0e-10);
            Assert.assertTrue(v == sphere.getSupport()[i++]);
        }
        Assert.assertTrue(sphere.contains (new Vector3D(-22.999, 2, 2)));
        Assert.assertFalse(sphere.contains(new Vector3D(-23.001, 2, 2)));
        Assert.assertTrue(sphere.contains (new Vector3D( 26.999, 2, 2)));
        Assert.assertFalse(sphere.contains(new Vector3D( 27.001, 2, 2)));
        Assert.assertTrue(sphere.contains (new Vector3D(2, -22.999, 2)));
        Assert.assertFalse(sphere.contains(new Vector3D(2, -23.001, 2)));
        Assert.assertTrue(sphere.contains (new Vector3D(2,  26.999, 2)));
        Assert.assertFalse(sphere.contains(new Vector3D(2,  27.001, 2)));
        Assert.assertTrue(sphere.contains (new Vector3D(2, 2, -22.999)));
        Assert.assertFalse(sphere.contains(new Vector3D(2, 2, -23.001)));
        Assert.assertTrue(sphere.contains (new Vector3D(2, 2,  26.999)));
        Assert.assertFalse(sphere.contains(new Vector3D(2, 2,  27.001)));
        Assert.assertEquals(0.0, new Vector3D(2.0, 2.0, 2.0).distance(sphere.getCenter()), 1.0e-10);
        Assert.assertEquals(4, sphere.getSupportSize());
    }

    @Test
    public void testRandom() {
        final RandomGenerator random = new Well1024a(0xd015982e9f31ee04l);
        final UnitSphereRandomVectorGenerator sr = new UnitSphereRandomVectorGenerator(3, random);
        for (int i = 0; i < 100; ++i) {
            double d = 25 * random.nextDouble();
            double refRadius = 10 * random.nextDouble();
            Vector3D refCenter = new Vector3D(d, new Vector3D(sr.nextVector()));
            List<Vector3D> support = new ArrayList();
            for (int j = 0; j < 5; ++j) {
                support.add(new Vector3D(1.0, refCenter, refRadius, new Vector3D(sr.nextVector())));
            }
            EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);
            Assert.assertEquals(0.0, refCenter.distance(sphere.getCenter()), 4e-7 * refRadius);
            Assert.assertEquals(refRadius, sphere.getRadius(), 1e-7 * refRadius);
        }

    }

    @Test
    public void testDegeneratedCase() {
       final List<Vector3D> support =
               Arrays.asList(new Vector3D(FastMath.scalb(-8039905610797991.0, -50),   //   -7.140870659936730
                                          FastMath.scalb(-4663475464714142.0, -48),   //  -16.567993074240455
                                          FastMath.scalb( 6592658872616184.0, -49)),  //   11.710914678204503
                             new Vector3D(FastMath.scalb(-8036658568968473.0, -50),   //   -7.137986707455888
                                          FastMath.scalb(-4664256346424880.0, -48),   //  -16.570767323375720
                                          FastMath.scalb( 6591357011730307.0, -49)),  //  11.708602108715928)
                             new Vector3D(FastMath.scalb(-8037820142977230.0, -50),   //   -7.139018392423351
                                          FastMath.scalb(-4665280434237813.0, -48),   //  -16.574405614157020
                                          FastMath.scalb( 6592435966112099.0, -49)),  //   11.710518716711425
                             new Vector3D(FastMath.scalb(-8038007803611611.0, -50),   //   -7.139185068549035
                                          FastMath.scalb(-4664291215918380.0, -48),   //  -16.570891204702250
                                          FastMath.scalb( 6595270610894208.0, -49))); //   11.715554057357394
        EnclosingBall<Euclidean3D, Vector3D> sphere = new SphereGenerator().ballOnSupport(support);

        // the following values have been computed using Emacs calc with exact arithmetic from the
        // rational representation corresponding to the scalb calls (i.e. -8039905610797991/2^50, ...)
        // The results were converted to decimal representation rounded to 1.0e-30 when writing the reference
        // values in this test
        Assert.assertEquals(  0.003616820213530053297575846168, sphere.getRadius(),        1.0e-20);
        Assert.assertEquals( -7.139325643360503322823511839511, sphere.getCenter().getX(), 1.0e-20);
        Assert.assertEquals(-16.571096474251747245361467833760, sphere.getCenter().getY(), 1.0e-20);
        Assert.assertEquals( 11.711945804096960876521111630800, sphere.getCenter().getZ(), 1.0e-20);

        for (Vector3D v : support) {
            Assert.assertTrue(sphere.contains(v, 1.0e-14));
        }

    }

}