Commons Math example source code file (MullerSolverTest.java)

This example Commons Math source code file (MullerSolverTest.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

deprecated, expecting, expm1function, illegalargumentexception, mathexception, mathexception, mullersolver, mullersolver, quinticfunction, sinfunction, univariaterealfunction, univariaterealfunction, univariaterealsolver, univariaterealsolver

The Commons Math MullerSolverTest.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 Muller solver.
 * <p>
 * Muller's method converges almost quadratically near roots, but it can
 * be very slow in regions far away from zeros. Test runs show that for
 * reasonably good initial values, for a default absolute accuracy of 1E-6,
 * it generally takes 5 to 10 iterations for the solver to converge.
 * <p>
 * Tests for the exponential function illustrate the situations where
 * Muller solver performs poorly.
 *
 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
 */
public final class MullerSolverTest extends TestCase {

    /**
     * Test deprecated APIs.
     */
    @Deprecated
    public void testDeprecated() throws MathException {
        UnivariateRealFunction f = new SinFunction();
        UnivariateRealSolver solver = new MullerSolver(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 deprecated APIs.
     */
    @Deprecated
    public void testDeprecated2() throws MathException {
        UnivariateRealFunction f = new QuinticFunction();
        MullerSolver solver = new MullerSolver(f);
        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.solve2(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.solve2(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.solve2(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 MullerSolver();
        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 sine function using solve2().
     */
    public void testSinFunction2() throws MathException {
        UnivariateRealFunction f = new SinFunction();
        MullerSolver solver = new MullerSolver();
        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.solve2(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.solve2(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 MullerSolver();
        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 quintic function using solve2().
     */
    public void testQuinticFunction2() throws MathException {
        UnivariateRealFunction f = new QuinticFunction();
        MullerSolver solver = new MullerSolver();
        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.solve2(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.solve2(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.solve2(f, min, max);
        assertEquals(expected, result, tolerance);
    }

    /**
     * Test of solver for the exponential function.
     * <p>
     * It takes 10 to 15 iterations for the last two tests to converge.
     * In fact, if not for the bisection alternative, the solver would
     * exceed the default maximal iteration of 100.
     */
    public void testExpm1Function() throws MathException {
        UnivariateRealFunction f = new Expm1Function();
        UnivariateRealSolver solver = new MullerSolver();
        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 solver for the exponential function using solve2().
     * <p>
     * It takes 25 to 50 iterations for the last two tests to converge.
     */
    public void testExpm1Function2() throws MathException {
        UnivariateRealFunction f = new Expm1Function();
        MullerSolver solver = new MullerSolver();
        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.solve2(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.solve2(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.solve2(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 MullerSolver();

        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
        }
    }
}