    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    }