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 * https://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 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22
23 package org.hipparchus.analysis.function;
24
25 import org.hipparchus.analysis.differentiation.Derivative;
26 import org.hipparchus.analysis.differentiation.UnivariateDifferentiableFunction;
27 import org.hipparchus.util.FastMath;
28
29 /**
30 * Natural logarithm function.
31 *
32 */
33 public class Log implements UnivariateDifferentiableFunction {
34
35 /** Empty constructor.
36 * <p>
37 * This constructor is not strictly necessary, but it prevents spurious
38 * javadoc warnings with JDK 18 and later.
39 * </p>
40 * @since 3.0
41 */
42 public Log() { // NOPMD - unnecessary constructor added intentionally to make javadoc happy
43 // nothing to do
44 }
45
46 /** {@inheritDoc} */
47 @Override
48 public double value(double x) {
49 return FastMath.log(x);
50 }
51
52 /** {@inheritDoc} */
53 @Override
54 public <T extends Derivative<T>> T value(T x) {
55 return x.log();
56 }
57
58 }