1 /* 2 * Copyright 2003-2004 The Apache Software Foundation. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package org.apache.commons.math.analysis; 17 18 import org.apache.commons.math.FunctionEvaluationException; 19 20 /** 21 * Auxillary class for testing solvers. 22 * 23 * The function is extraordinarily well behaved around zero roots: it 24 * has an inflection point there (second order derivative is zero), 25 * which means linear approximation (Regula Falsi) will converge 26 * quadratically. 27 * 28 * @version $Revision: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (Sat, 26 Feb 2005) $ 29 */ 30 public class SinFunction implements DifferentiableUnivariateRealFunction { 31 32 /* Evaluate sinus fuction. 33 * @see org.apache.commons.math.UnivariateRealFunction#value(double) 34 */ 35 public double value(double x) throws FunctionEvaluationException { 36 return Math.sin(x); 37 } 38 39 /* First derivative of sinus function 40 */ 41 public UnivariateRealFunction derivative() { 42 return new UnivariateRealFunction() { 43 public double value(double x) throws FunctionEvaluationException { 44 return Math.cos(x); 45 } 46 }; 47 } 48 49 }