src/test/org/apache/commons/math/analysis/NewtonSolverTest.java

/*
 * 
 * Copyright (c) 2003-2004 The Apache Software Foundation. All rights reserved.
 * 
 * Licensed 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;

import org.apache.commons.math.MathException;

import junit.framework.TestCase;

/**
 * @version $Revision$ $Date$
 */
public final class NewtonSolverTest extends TestCase {
    /**
     *
     */
    public void testSinZero() throws MathException {
        DifferentiableUnivariateRealFunction f = new SinFunction();
        double result;
        
        UnivariateRealSolver solver = new NewtonSolver(f);
        result = solver.solve(3, 4);
        assertEquals(result, Math.PI, solver.getAbsoluteAccuracy());

        result = solver.solve(1, 4);
        assertEquals(result, Math.PI, solver.getAbsoluteAccuracy());
        
        //TODO:  create abstract solver test class, move these there
        assertEquals(result, solver.getResult(), 0);
        assertTrue(solver.getIterationCount() > 0);
    }

    /**
     *
     */
    public void testQuinticZero() throws MathException {
        DifferentiableUnivariateRealFunction f = new QuinticFunction();
        double result;

        UnivariateRealSolver solver = new BisectionSolver(f);
        result = solver.solve(-0.2, 0.2);
        assertEquals(result, 0, solver.getAbsoluteAccuracy());

        result = solver.solve(-0.1, 0.3);
        assertEquals(result, 0, solver.getAbsoluteAccuracy());

        result = solver.solve(-0.3, 0.45);
        assertEquals(result, 0, solver.getAbsoluteAccuracy());

        result = solver.solve(0.3, 0.7);
        assertEquals(result, 0.5, solver.getAbsoluteAccuracy());

        result = solver.solve(0.2, 0.6);
        assertEquals(result, 0.5, solver.getAbsoluteAccuracy());

        result = solver.solve(0.05, 0.95);
        assertEquals(result, 0.5, solver.getAbsoluteAccuracy());

        result = solver.solve(0.85, 1.25);
        assertEquals(result, 1.0, solver.getAbsoluteAccuracy());

        result = solver.solve(0.8, 1.2);
        assertEquals(result, 1.0, solver.getAbsoluteAccuracy());

        result = solver.solve(0.85, 1.75);
        assertEquals(result, 1.0, solver.getAbsoluteAccuracy());

        result = solver.solve(0.55, 1.45);
        assertEquals(result, 1.0, solver.getAbsoluteAccuracy());

        result = solver.solve(0.85, 5);
        assertEquals(result, 1.0, solver.getAbsoluteAccuracy());
    }
}