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 * Constant function.
026 *
027 * @since 3.0
028 * @version $Id: Constant.java 1424087 2012-12-19 20:32:50Z luc $
029 */
030 public class Constant implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction {
031 /** Constant. */
032 private final double c;
033
034 /**
035 * @param c Constant.
036 */
037 public Constant(double c) {
038 this.c = c;
039 }
040
041 /** {@inheritDoc} */
042 public double value(double x) {
043 return c;
044 }
045
046 /** {@inheritDoc}
047 * @deprecated as of 3.1, replaced by {@link #value(DerivativeStructure)}
048 */
049 @Deprecated
050 public DifferentiableUnivariateFunction derivative() {
051 return new Constant(0);
052 }
053
054 /** {@inheritDoc}
055 * @since 3.1
056 */
057 public DerivativeStructure value(final DerivativeStructure t) {
058 return new DerivativeStructure(t.getFreeParameters(), t.getOrder(), c);
059 }
060
061 }