1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.math3.analysis.function; 19 20 import org.apache.commons.math3.analysis.DifferentiableUnivariateFunction; 21 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure; 22 import org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiableFunction; 23 24 /** 25 * Constant function. 26 * 27 * @since 3.0 28 */ 29 public class Constant implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction { 30 /** Constant. */ 31 private final double c; 32 33 /** 34 * @param c Constant. 35 */ Constant(double c)36 public Constant(double c) { 37 this.c = c; 38 } 39 40 /** {@inheritDoc} */ value(double x)41 public double value(double x) { 42 return c; 43 } 44 45 /** {@inheritDoc} 46 * @deprecated as of 3.1, replaced by {@link #value(DerivativeStructure)} 47 */ 48 @Deprecated derivative()49 public DifferentiableUnivariateFunction derivative() { 50 return new Constant(0); 51 } 52 53 /** {@inheritDoc} 54 * @since 3.1 55 */ value(final DerivativeStructure t)56 public DerivativeStructure value(final DerivativeStructure t) { 57 return new DerivativeStructure(t.getFreeParameters(), t.getOrder(), c); 58 } 59 60 } 61