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.math4.legacy.analysis.function;
19
20 import org.apache.commons.math4.legacy.analysis.differentiation.DerivativeStructure;
21 import org.apache.commons.math4.legacy.analysis.differentiation.UnivariateDifferentiableFunction;
22
23 /**
24 * Identity function.
25 *
26 * @since 3.0
27 */
28 public class Identity implements UnivariateDifferentiableFunction {
29 /** {@inheritDoc} */
30 @Override
31 public double value(double x) {
32 return x;
33 }
34
35 /** {@inheritDoc}
36 * @since 3.1
37 */
38 @Override
39 public DerivativeStructure value(final DerivativeStructure t) {
40 return t;
41 }
42 }