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: 480442 $ $Date: 2006-11-29 00:21:22 -0700 (Wed, 29 Nov 2006) $
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 }