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.solvers;
24
25
26 /**
27 * Implements the <em>Illinois</em> method for root-finding (approximating
28 * a zero of a univariate real function). It is a modified
29 * {@link RegulaFalsiSolver <em>Regula Falsi</em>} method.
30 *
31 * <p>Like the <em>Regula Falsi</em> method, convergence is guaranteed by
32 * maintaining a bracketed solution. The <em>Illinois</em> method however,
33 * should converge much faster than the original <em>Regula Falsi</em>
34 * method. Furthermore, this implementation of the <em>Illinois</em> method
35 * should not suffer from the same implementation issues as the <em>Regula
36 * Falsi</em> method, which may fail to convergence in certain cases.</p>
37 *
38 * <p>The <em>Illinois</em> method assumes that the function is continuous,
39 * but not necessarily smooth.</p>
40 *
41 * <p>Implementation based on the following article: M. Dowell and P. Jarratt,
42 * <em>A modified regula falsi method for computing the root of an
43 * equation</em>, BIT Numerical Mathematics, volume 11, number 2,
44 * pages 168-174, Springer, 1971.</p>
45 *
46 */
47 public class IllinoisSolver extends BaseSecantSolver {
48
49 /** Construct a solver with default accuracy (1e-6). */
50 public IllinoisSolver() {
51 super(DEFAULT_ABSOLUTE_ACCURACY, Method.ILLINOIS);
52 }
53
54 /**
55 * Construct a solver.
56 *
57 * @param absoluteAccuracy Absolute accuracy.
58 */
59 public IllinoisSolver(final double absoluteAccuracy) {
60 super(absoluteAccuracy, Method.ILLINOIS);
61 }
62
63 /**
64 * Construct a solver.
65 *
66 * @param relativeAccuracy Relative accuracy.
67 * @param absoluteAccuracy Absolute accuracy.
68 */
69 public IllinoisSolver(final double relativeAccuracy,
70 final double absoluteAccuracy) {
71 super(relativeAccuracy, absoluteAccuracy, Method.ILLINOIS);
72 }
73
74 /**
75 * Construct a solver.
76 *
77 * @param relativeAccuracy Relative accuracy.
78 * @param absoluteAccuracy Absolute accuracy.
79 * @param functionValueAccuracy Maximum function value error.
80 */
81 public IllinoisSolver(final double relativeAccuracy,
82 final double absoluteAccuracy,
83 final double functionValueAccuracy) {
84 super(relativeAccuracy, absoluteAccuracy, functionValueAccuracy, Method.ILLINOIS);
85 }
86 }