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.DifferentiableUnivariateFunction;
021    import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
022    import org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiableFunction;
023    
024    /**
025     * Minus function.
026     *
027     * @since 3.0
028     * @version $Id: Minus.java 1424087 2012-12-19 20:32:50Z luc $
029     */
030    public class Minus implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction {
031        /** {@inheritDoc} */
032        public double value(double x) {
033            return -x;
034        }
035    
036        /** {@inheritDoc}
037         * @deprecated as of 3.1, replaced by {@link #value(DerivativeStructure)}
038         */
039        @Deprecated
040        public DifferentiableUnivariateFunction derivative() {
041            return new Constant(-1);
042        }
043    
044        /** {@inheritDoc}
045         * @since 3.1
046         */
047        public DerivativeStructure value(final DerivativeStructure t) {
048            return t.negate();
049        }
050    
051    }