    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: 1.14 $ $Date: 2004/07/17 21:19:39 $
    26   */
    27  public class QuinticFunction implements DifferentiableUnivariateRealFunction, Serializable {
    28
    29      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  }