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 purposes. 23 * 24 * @version $Revision: 786927 $ $Date: 2009-06-20 19:37:47 -0400 (Sat, 20 Jun 2009) $ 25 */ 26 public class Expm1Function implements DifferentiableUnivariateRealFunction { 27 28 public double value(double x) throws FunctionEvaluationException { 29 // Math.expm1() is available in jdk 1.5 but not in jdk 1.4.2. 30 return Math.exp(x) - 1.0; 31 } 32 33 public UnivariateRealFunction derivative() { 34 return new UnivariateRealFunction() { 35 public double value(double x) throws FunctionEvaluationException { 36 return Math.exp(x); 37 } 38 }; 39 } 40 }