001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.math.analysis; 018 019 import org.apache.commons.math.FunctionEvaluationException; 020 021 /** 022 * Auxillary class for testing solvers. 023 * 024 * The function is extraordinarily well behaved around zero roots: it 025 * has an inflection point there (second order derivative is zero), 026 * which means linear approximation (Regula Falsi) will converge 027 * quadratically. 028 * 029 * @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $ 030 */ 031 public class SinFunction implements DifferentiableUnivariateRealFunction { 032 033 /* Evaluate sinus fuction. 034 * @see org.apache.commons.math.UnivariateRealFunction#value(double) 035 */ 036 public double value(double x) throws FunctionEvaluationException { 037 return Math.sin(x); 038 } 039 040 /* First derivative of sinus function 041 */ 042 public UnivariateRealFunction derivative() { 043 return new UnivariateRealFunction() { 044 public double value(double x) throws FunctionEvaluationException { 045 return Math.cos(x); 046 } 047 }; 048 } 049 050 }