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 java.io.Serializable;
19  
20  import org.apache.commons.math.FunctionEvaluationException;
21  
22  /**
23   * Auxillary class for testing solvers.
24   *
25   * @version $Revision: 348519 $ $Date: 2005-11-23 12:12:18 -0700 (Wed, 23 Nov 2005) $ 
26   */
27  public class QuinticFunction implements DifferentiableUnivariateRealFunction, Serializable {
28  
29      private static final long serialVersionUID = -8866263034920607152L;
30  
31      /* Evaluate quintic.
32       * @see org.apache.commons.math.UnivariateRealFunction#value(double)
33       */
34      public double value(double x) throws FunctionEvaluationException {
35          return (x-1)*(x-0.5)*x*(x+0.5)*(x+1);
36      }
37  
38      public UnivariateRealFunction derivative() {
39          return new UnivariateRealFunction() {
40              public double value(double x) throws FunctionEvaluationException {
41                  return (5*x*x-3.75)*x*x+0.25;
42              }
43          };
44      }
45  }