1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.analysis; 18 19 import org.apache.commons.math.FunctionEvaluationException; 20 21 /** 22 * Auxillary class for testing solvers. 23 * 24 * The function is extraordinarily well behaved around zero roots: it 25 * has an inflection point there (second order derivative is zero), 26 * which means linear approximation (Regula Falsi) will converge 27 * quadratically. 28 * 29 * @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $ 30 */ 31 public class SinFunction implements DifferentiableUnivariateRealFunction { 32 33 /* Evaluate sinus fuction. 34 * @see org.apache.commons.math.UnivariateRealFunction#value(double) 35 */ 36 public double value(double x) throws FunctionEvaluationException { 37 return Math.sin(x); 38 } 39 40 /* First derivative of sinus function 41 */ 42 public UnivariateRealFunction derivative() { 43 return new UnivariateRealFunction() { 44 public double value(double x) throws FunctionEvaluationException { 45 return Math.cos(x); 46 } 47 }; 48 } 49 50 }