Commons Math example source code file (RiddersSolverTest.java)

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

Java - Commons Math tags/keywords

exception, expecting, expm1function, illegalargumentexception, illegalargumentexception, mathexception, ridderssolver, ridderssolver, sinfunction, testcase, univariaterealfunction, univariaterealfunction, univariaterealsolver, univariaterealsolver

The Commons Math RiddersSolverTest.java 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.math.analysis.solvers;

import org.apache.commons.math.MathException;
import org.apache.commons.math.analysis.Expm1Function;
import org.apache.commons.math.analysis.QuinticFunction;
import org.apache.commons.math.analysis.SinFunction;
import org.apache.commons.math.analysis.UnivariateRealFunction;

import junit.framework.TestCase;

/**
 * Testcase for Ridders solver.
 * <p>
 * Ridders' method converges superlinearly, more specific, its rate of
 * convergence is sqrt(2). Test runs show that for a default absolute
 * accuracy of 1E-6, it generally takes less than 5 iterations for close
 * initial bracket and 5 to 10 iterations for distant initial bracket
 * to converge.
 *
 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
 */
public final class RiddersSolverTest extends TestCase {

    /**
     * Test the deprecated APIs.
     */
    @Deprecated
    public void testDeprecated() throws MathException {
        UnivariateRealFunction f = new SinFunction();
        UnivariateRealSolver solver = new RiddersSolver(f);
        double min, max, expected, result, tolerance;

        min = 3.0; max = 4.0; expected = Math.PI;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(min, max);
        assertEquals(expected, result, tolerance);

        min = -1.0; max = 1.5; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(min, max);
        assertEquals(expected, result, tolerance);
    }

    /**
     * Test of solver for the sine function.
     */
    public void testSinFunction() throws MathException {
        UnivariateRealFunction f = new SinFunction();
        UnivariateRealSolver solver = new RiddersSolver();
        double min, max, expected, result, tolerance;

        min = 3.0; max = 4.0; expected = Math.PI;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);

        min = -1.0; max = 1.5; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);
    }

    /**
     * Test of solver for the quintic function.
     */
    public void testQuinticFunction() throws MathException {
        UnivariateRealFunction f = new QuinticFunction();
        UnivariateRealSolver solver = new RiddersSolver();
        double min, max, expected, result, tolerance;

        min = -0.4; max = 0.2; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);

        min = 0.75; max = 1.5; expected = 1.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);

        min = -0.9; max = -0.2; expected = -0.5;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);
    }

    /**
     * Test of solver for the exponential function.
     */
    public void testExpm1Function() throws MathException {
        UnivariateRealFunction f = new Expm1Function();
        UnivariateRealSolver solver = new RiddersSolver();
        double min, max, expected, result, tolerance;

        min = -1.0; max = 2.0; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);

        min = -20.0; max = 10.0; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);

        min = -50.0; max = 100.0; expected = 0.0;
        tolerance = Math.max(solver.getAbsoluteAccuracy(),
                    Math.abs(expected * solver.getRelativeAccuracy()));
        result = solver.solve(f, min, max);
        assertEquals(expected, result, tolerance);
    }

    /**
     * Test of parameters for the solver.
     */
    public void testParameters() throws Exception {
        UnivariateRealFunction f = new SinFunction();
        UnivariateRealSolver solver = new RiddersSolver();

        try {
            // bad interval
            solver.solve(f, 1, -1);
            fail("Expecting IllegalArgumentException - bad interval");
        } catch (IllegalArgumentException ex) {
            // expected
        }
        try {
            // no bracketing
            solver.solve(f, 2, 3);
            fail("Expecting IllegalArgumentException - no bracketing");
        } catch (IllegalArgumentException ex) {
            // expected
        }
    }
}