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
018 package org.apache.commons.math3.analysis.function;
019
020 import org.apache.commons.math3.analysis.FunctionUtils;
021 import org.apache.commons.math3.analysis.UnivariateFunction;
022 import org.apache.commons.math3.analysis.DifferentiableUnivariateFunction;
023 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
024 import org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiableFunction;
025
026 /**
027 * Inverse function.
028 *
029 * @since 3.0
030 * @version $Id: Inverse.java 1383441 2012-09-11 14:56:39Z luc $
031 */
032 public class Inverse implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction {
033 /** {@inheritDoc} */
034 public double value(double x) {
035 return 1 / x;
036 }
037
038 /** {@inheritDoc}
039 * @deprecated as of 3.1, replaced by {@link #value(DerivativeStructure)}
040 */
041 @Deprecated
042 public UnivariateFunction derivative() {
043 return FunctionUtils.toDifferentiableUnivariateFunction(this).derivative();
044 }
045
046 /** {@inheritDoc}
047 * @since 3.1
048 */
049 public DerivativeStructure value(final DerivativeStructure t) {
050 return t.reciprocal();
051 }
052
053 }