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Java example source code file (DiskGeneratorTest.java)

This example Java source code file (DiskGeneratorTest.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, diskgeneratortest, enclosingball, list, randomgenerator, test, unitsphererandomvectorgenerator, util, vector2d, well1024a

The DiskGeneratorTest.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.twod;

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.junit.Assert;
import org.junit.Test;


public class DiskGeneratorTest {

    @Test
    public void testSupport0Point() {
        List<Vector2D> support = Arrays.asList(new Vector2D[0]);
        EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
        Assert.assertTrue(disk.getRadius() < 0);
        Assert.assertEquals(0, disk.getSupportSize());
        Assert.assertEquals(0, disk.getSupport().length);
    }

    @Test
    public void testSupport1Point() {
        List<Vector2D> support = Arrays.asList(new Vector2D(1, 2));
        EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
        Assert.assertEquals(0.0, disk.getRadius(), 1.0e-10);
        Assert.assertTrue(disk.contains(support.get(0)));
        Assert.assertTrue(disk.contains(support.get(0), 0.5));
        Assert.assertFalse(disk.contains(new Vector2D(support.get(0).getX() + 0.1,
                                                      support.get(0).getY() - 0.1),
                                         0.001));
        Assert.assertTrue(disk.contains(new Vector2D(support.get(0).getX() + 0.1,
                                                     support.get(0).getY() - 0.1),
                                        0.5));
        Assert.assertEquals(0, support.get(0).distance(disk.getCenter()), 1.0e-10);
        Assert.assertEquals(1, disk.getSupportSize());
        Assert.assertTrue(support.get(0) == disk.getSupport()[0]);
    }

    @Test
    public void testSupport2Points() {
        List<Vector2D> support = Arrays.asList(new Vector2D(1, 0),
                                               new Vector2D(3, 0));
        EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
        Assert.assertEquals(1.0, disk.getRadius(), 1.0e-10);
        int i = 0;
        for (Vector2D v : support) {
            Assert.assertTrue(disk.contains(v));
            Assert.assertEquals(1.0, v.distance(disk.getCenter()), 1.0e-10);
            Assert.assertTrue(v == disk.getSupport()[i++]);
        }
        Assert.assertTrue(disk.contains(new Vector2D(2, 0.9)));
        Assert.assertFalse(disk.contains(Vector2D.ZERO));
        Assert.assertEquals(0.0, new Vector2D(2, 0).distance(disk.getCenter()), 1.0e-10);
        Assert.assertEquals(2, disk.getSupportSize());
    }

    @Test
    public void testSupport3Points() {
        List<Vector2D> support = Arrays.asList(new Vector2D(1, 0),
                                               new Vector2D(3, 0),
                                               new Vector2D(2, 2));
        EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
        Assert.assertEquals(5.0 / 4.0, disk.getRadius(), 1.0e-10);
        int i = 0;
        for (Vector2D v : support) {
            Assert.assertTrue(disk.contains(v));
            Assert.assertEquals(5.0 / 4.0, v.distance(disk.getCenter()), 1.0e-10);
            Assert.assertTrue(v == disk.getSupport()[i++]);
        }
        Assert.assertTrue(disk.contains(new Vector2D(2, 0.9)));
        Assert.assertFalse(disk.contains(new Vector2D(0.9,  0)));
        Assert.assertFalse(disk.contains(new Vector2D(3.1,  0)));
        Assert.assertTrue(disk.contains(new Vector2D(2.0, -0.499)));
        Assert.assertFalse(disk.contains(new Vector2D(2.0, -0.501)));
        Assert.assertEquals(0.0, new Vector2D(2.0, 3.0 / 4.0).distance(disk.getCenter()), 1.0e-10);
        Assert.assertEquals(3, disk.getSupportSize());
    }

    @Test
    public void testRandom() {
        final RandomGenerator random = new Well1024a(0x12faa818373ffe90l);
        final UnitSphereRandomVectorGenerator sr = new UnitSphereRandomVectorGenerator(2, random);
        for (int i = 0; i < 500; ++i) {
            double d = 25 * random.nextDouble();
            double refRadius = 10 * random.nextDouble();
            Vector2D refCenter = new Vector2D(d, new Vector2D(sr.nextVector()));
            List<Vector2D> support = new ArrayList();
            for (int j = 0; j < 3; ++j) {
                support.add(new Vector2D(1.0, refCenter, refRadius, new Vector2D(sr.nextVector())));
            }
            EnclosingBall<Euclidean2D, Vector2D> disk = new DiskGenerator().ballOnSupport(support);
            Assert.assertEquals(0.0, refCenter.distance(disk.getCenter()), 3e-9 * refRadius);
            Assert.assertEquals(refRadius, disk.getRadius(), 7e-10 * refRadius);
        }

    }
}

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