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
018package org.apache.commons.math4.analysis.function;
019
020import org.apache.commons.math4.analysis.differentiation.DerivativeStructure;
021import org.apache.commons.math4.analysis.differentiation.UnivariateDifferentiableFunction;
022
023/**
024 * Constant function.
025 *
026 * @since 3.0
027 */
028public class Constant implements UnivariateDifferentiableFunction {
029    /** Constant. */
030    private final double c;
031
032    /**
033     * @param c Constant.
034     */
035    public Constant(double c) {
036        this.c = c;
037    }
038
039    /** {@inheritDoc} */
040    @Override
041    public double value(double x) {
042        return c;
043    }
044
045    /** {@inheritDoc}
046     * @since 3.1
047     */
048    @Override
049    public DerivativeStructure value(final DerivativeStructure t) {
050        return new DerivativeStructure(t.getFreeParameters(), t.getOrder(), c);
051    }
052
053}