home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (RombergIntegratorTest.java)

This example Java source code file (RombergIntegratorTest.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

expecting, numberistoolargeexception, numberistoosmallexception, quinticfunction, rombergintegrator, rombergintegratortest, sin, test, univariatefunction, univariateintegrator

The RombergIntegratorTest.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.analysis.integration;

import org.apache.commons.math3.analysis.QuinticFunction;
import org.apache.commons.math3.analysis.UnivariateFunction;
import org.apache.commons.math3.analysis.function.Sin;
import org.apache.commons.math3.exception.NumberIsTooLargeException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.util.FastMath;
import org.junit.Assert;
import org.junit.Test;


/**
 * Test case for Romberg integrator.
 * <p>
 * Romberg algorithm is very fast for good behavior integrand. Test runs
 * show that for a default relative accuracy of 1E-6, it generally takes
 * takes less than 5 iterations for the integral to converge.
 *
 */
public final class RombergIntegratorTest {

    /**
     * Test of integrator for the sine function.
     */
    @Test
    public void testSinFunction() {
        UnivariateFunction f = new Sin();
        UnivariateIntegrator integrator = new RombergIntegrator();
        double min, max, expected, result, tolerance;

        min = 0; max = FastMath.PI; expected = 2;
        tolerance = FastMath.abs(expected * integrator.getRelativeAccuracy());
        result = integrator.integrate(100, f, min, max);
        Assert.assertTrue(integrator.getEvaluations() < 50);
        Assert.assertTrue(integrator.getIterations()  < 10);
        Assert.assertEquals(expected, result, tolerance);

        min = -FastMath.PI/3; max = 0; expected = -0.5;
        tolerance = FastMath.abs(expected * integrator.getRelativeAccuracy());
        result = integrator.integrate(100, f, min, max);
        Assert.assertTrue(integrator.getEvaluations() < 50);
        Assert.assertTrue(integrator.getIterations()  < 10);
        Assert.assertEquals(expected, result, tolerance);
    }

    /**
     * Test of integrator for the quintic function.
     */
    @Test
    public void testQuinticFunction() {
        UnivariateFunction f = new QuinticFunction();
        UnivariateIntegrator integrator = new RombergIntegrator();
        double min, max, expected, result, tolerance;

        min = 0; max = 1; expected = -1.0/48;
        tolerance = FastMath.abs(expected * integrator.getRelativeAccuracy());
        result = integrator.integrate(100, f, min, max);
        Assert.assertTrue(integrator.getEvaluations() < 10);
        Assert.assertTrue(integrator.getIterations()  < 5);
        Assert.assertEquals(expected, result, tolerance);

        min = 0; max = 0.5; expected = 11.0/768;
        tolerance = FastMath.abs(expected * integrator.getRelativeAccuracy());
        result = integrator.integrate(100, f, min, max);
        Assert.assertTrue(integrator.getEvaluations() < 10);
        Assert.assertTrue(integrator.getIterations()  < 5);
        Assert.assertEquals(expected, result, tolerance);

        min = -1; max = 4; expected = 2048/3.0 - 78 + 1.0/48;
        tolerance = FastMath.abs(expected * integrator.getRelativeAccuracy());
        result = integrator.integrate(100, f, min, max);
        Assert.assertTrue(integrator.getEvaluations() < 10);
        Assert.assertTrue(integrator.getIterations()  < 5);
        Assert.assertEquals(expected, result, tolerance);
    }

    /**
     * Test of parameters for the integrator.
     */
    @Test
    public void testParameters() {
        UnivariateFunction f = new Sin();

        try {
            // bad interval
            new RombergIntegrator().integrate(1000, f, 1, -1);
            Assert.fail("Expecting NumberIsTooLargeException - bad interval");
        } catch (NumberIsTooLargeException ex) {
            // expected
        }
        try {
            // bad iteration limits
            new RombergIntegrator(5, 4);
            Assert.fail("Expecting NumberIsTooSmallException - bad iteration limits");
        } catch (NumberIsTooSmallException ex) {
            // expected
        }
        try {
            // bad iteration limits
            new RombergIntegrator(10, 50);
            Assert.fail("Expecting NumberIsTooLargeException - bad iteration limits");
        } catch (NumberIsTooLargeException ex) {
            // expected
        }
    }
}

Other Java examples (source code examples)

Here is a short list of links related to this Java RombergIntegratorTest.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.