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 import org.apache.commons.math3.util.FastMath;
026
027 /**
028 * Power function.
029 *
030 * @since 3.0
031 * @version $Id: Power.java 1383441 2012-09-11 14:56:39Z luc $
032 */
033 public class Power implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction {
034 /** Power. */
035 private final double p;
036
037 /**
038 * @param p Power.
039 */
040 public Power(double p) {
041 this.p = p;
042 }
043
044 /** {@inheritDoc} */
045 public double value(double x) {
046 return FastMath.pow(x, p);
047 }
048
049 /** {@inheritDoc}
050 * @deprecated as of 3.1, replaced by {@link #value(DerivativeStructure)}
051 */
052 @Deprecated
053 public UnivariateFunction derivative() {
054 return FunctionUtils.toDifferentiableUnivariateFunction(this).derivative();
055 }
056
057 /** {@inheritDoc}
058 * @since 3.1
059 */
060 public DerivativeStructure value(final DerivativeStructure t) {
061 return t.pow(p);
062 }
063
064 }