/*
* 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.math4.geometry.enclosing;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.math4.geometry.enclosing.EnclosingBall;
import org.apache.commons.math4.geometry.enclosing.WelzlEncloser;
import org.apache.commons.math4.geometry.euclidean.twod.DiskGenerator;
import org.apache.commons.math4.geometry.euclidean.twod.Euclidean2D;
import org.apache.commons.math4.geometry.euclidean.twod.Cartesian2D;
import org.apache.commons.rng.UniformRandomProvider;
import org.apache.commons.rng.simple.RandomSource;
import org.junit.Assert;
import org.junit.Test;
public class WelzlEncloser2DTest {
@Test
public void testNullList() {
DiskGenerator generator = new DiskGenerator();
WelzlEncloser<Euclidean2D, Cartesian2D> encloser =
new WelzlEncloser<>(1.0e-10, generator);
EnclosingBall<Euclidean2D, Cartesian2D> ball = encloser.enclose(null);
Assert.assertTrue(ball.getRadius() < 0);
}
@Test
public void testNoPoints() {
DiskGenerator generator = new DiskGenerator();
WelzlEncloser<Euclidean2D, Cartesian2D> encloser =
new WelzlEncloser<>(1.0e-10, generator);
EnclosingBall<Euclidean2D, Cartesian2D> ball = encloser.enclose(new ArrayList<Cartesian2D>());
Assert.assertTrue(ball.getRadius() < 0);
}
@Test
public void testRegularPoints() {
List<Cartesian2D> list = buildList(22, 26, 30, 38, 64, 28, 8, 54, 11, 15);
checkDisk(list, Arrays.asList(list.get(2), list.get(3), list.get(4)));
}
@Test
public void testSolutionOnDiameter() {
List<Cartesian2D> list = buildList(22, 26, 30, 38, 64, 28, 8, 54);
checkDisk(list, Arrays.asList(list.get(2), list.get(3)));
}
@Test
public void testReducingBall1() {
List<Cartesian2D> list = buildList(0.05380958511396061, 0.57332359658700000,
0.99348810731127870, 0.02056421361521466,
0.01203950647796437, 0.99779675042261860,
0.00810189987706078, 0.00589246003827815,
0.00465180821202149, 0.99219972923046940);
checkDisk(list, Arrays.asList(list.get(1), list.get(3), list.get(4)));
}
@Test
public void testReducingBall2() {
List<Cartesian2D> list = buildList(0.016930586154703, 0.333955448537779,
0.987189104892331, 0.969778855274507,
0.983696889599935, 0.012904580013266,
0.013114499572905, 0.034740156356895);
checkDisk(list, Arrays.asList(list.get(1), list.get(2), list.get(3)));
}
@Test
public void testLargeSamples() {
UniformRandomProvider random = RandomSource.create(RandomSource.WELL_1024_A, 0xa2a63cad12c01fb2l);
for (int k = 0; k < 100; ++k) {
int nbPoints = random.nextInt(10000);
List<Cartesian2D> points = new ArrayList<>();
for (int i = 0; i < nbPoints; ++i) {
double x = random.nextDouble();
double y = random.nextDouble();
points.add(new Cartesian2D(x, y));
}
checkDisk(points);
}
}
private List<Cartesian2D> buildList(final double ... coordinates) {
List<Cartesian2D> list = new ArrayList<>(coordinates.length / 2);
for (int i = 0; i < coordinates.length; i += 2) {
list.add(new Cartesian2D(coordinates[i], coordinates[i + 1]));
}
return list;
}
private void checkDisk(List<Cartesian2D> points, List<Cartesian2D> refSupport) {
EnclosingBall<Euclidean2D, Cartesian2D> disk = checkDisk(points);
// compare computed disk with expected disk
DiskGenerator generator = new DiskGenerator();
EnclosingBall<Euclidean2D, Cartesian2D> expected = generator.ballOnSupport(refSupport);
Assert.assertEquals(refSupport.size(), disk.getSupportSize());
Assert.assertEquals(expected.getRadius(), disk.getRadius(), 1.0e-10);
Assert.assertEquals(expected.getCenter().getX(), disk.getCenter().getX(), 1.0e-10);
Assert.assertEquals(expected.getCenter().getY(), disk.getCenter().getY(), 1.0e-10);
for (Cartesian2D s : disk.getSupport()) {
boolean found = false;
for (Cartesian2D rs : refSupport) {
if (s == rs) {
found = true;
}
}
Assert.assertTrue(found);
}
// check removing any point of the support disk fails to enclose the point
for (int i = 0; i < disk.getSupportSize(); ++i) {
List<Cartesian2D> reducedSupport = new ArrayList<>();
int count = 0;
for (Cartesian2D s : disk.getSupport()) {
if (count++ != i) {
reducedSupport.add(s);
}
}
EnclosingBall<Euclidean2D, Cartesian2D> reducedDisk = generator.ballOnSupport(reducedSupport);
boolean foundOutside = false;
for (int j = 0; j < points.size() && !foundOutside; ++j) {
if (!reducedDisk.contains(points.get(j), 1.0e-10)) {
foundOutside = true;
}
}
Assert.assertTrue(foundOutside);
}
}
private EnclosingBall<Euclidean2D, Cartesian2D> checkDisk(List<Cartesian2D> points) {
WelzlEncloser<Euclidean2D, Cartesian2D> encloser =
new WelzlEncloser<>(1.0e-10, new DiskGenerator());
EnclosingBall<Euclidean2D, Cartesian2D> disk = encloser.enclose(points);
// all points are enclosed
for (Cartesian2D v : points) {
Assert.assertTrue(disk.contains(v, 1.0e-10));
}
for (Cartesian2D v : points) {
boolean inSupport = false;
for (Cartesian2D s : disk.getSupport()) {
if (v == s) {
inSupport = true;
}
}
if (inSupport) {
// points on the support should be outside of reduced ball
Assert.assertFalse(disk.contains(v, -0.001));
}
}
return disk;
}
}