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     * @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $ 
025     */
026    public class QuinticFunction implements DifferentiableUnivariateRealFunction {
027    
028        /* Evaluate quintic.
029         * @see org.apache.commons.math.UnivariateRealFunction#value(double)
030         */
031        public double value(double x) throws FunctionEvaluationException {
032            return (x-1)*(x-0.5)*x*(x+0.5)*(x+1);
033        }
034    
035        public UnivariateRealFunction derivative() {
036            return new UnivariateRealFunction() {
037                public double value(double x) throws FunctionEvaluationException {
038                    return (5*x*x-3.75)*x*x+0.25;
039                }
040            };
041        }
042    }