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.solvers;
19
20 import org.apache.commons.math4.legacy.analysis.UnivariateFunction;
21
22 /** Interface for {@link UnivariateSolver (univariate real) root-finding
23 * algorithms} that maintain a bracketed solution. There are several advantages
24 * to having such root-finding algorithms:
25 * <ul>
26 * <li>The bracketed solution guarantees that the root is kept within the
27 * interval. As such, these algorithms generally also guarantee
28 * convergence.</li>
29 * <li>The bracketed solution means that we have the opportunity to only
30 * return roots that are greater than or equal to the actual root, or
31 * are less than or equal to the actual root. That is, we can control
32 * whether under-approximations and over-approximations are
33 * {@link AllowedSolution allowed solutions}. Other root-finding
34 * algorithms can usually only guarantee that the solution (the root that
35 * was found) is around the actual root.</li>
36 * </ul>
37 *
38 * <p>For backwards compatibility, all root-finding algorithms must have
39 * {@link AllowedSolution#ANY_SIDE ANY_SIDE} as default for the allowed
40 * solutions.</p>
41 * @param <FUNC> Type of function to solve.
42 *
43 * @see AllowedSolution
44 * @since 3.0
45 */
46 public interface BracketedUnivariateSolver<FUNC extends UnivariateFunction>
47 extends BaseUnivariateSolver<FUNC> {
48
49 /**
50 * Solve for a zero in the given interval.
51 * A solver may require that the interval brackets a single zero root.
52 * Solvers that do require bracketing should be able to handle the case
53 * where one of the endpoints is itself a root.
54 *
55 * @param maxEval Maximum number of evaluations.
56 * @param f Function to solve.
57 * @param min Lower bound for the interval.
58 * @param max Upper bound for the interval.
59 * @param allowedSolution The kind of solutions that the root-finding algorithm may
60 * accept as solutions.
61 * @return A value where the function is zero.
62 * @throws org.apache.commons.math4.legacy.exception.MathIllegalArgumentException
63 * if the arguments do not satisfy the requirements specified by the solver.
64 * @throws org.apache.commons.math4.legacy.exception.TooManyEvaluationsException if
65 * the allowed number of evaluations is exceeded.
66 */
67 double solve(int maxEval, FUNC f, double min, double max,
68 AllowedSolution allowedSolution);
69
70 /**
71 * Solve for a zero in the given interval, start at {@code startValue}.
72 * A solver may require that the interval brackets a single zero root.
73 * Solvers that do require bracketing should be able to handle the case
74 * where one of the endpoints is itself a root.
75 *
76 * @param maxEval Maximum number of evaluations.
77 * @param f Function to solve.
78 * @param min Lower bound for the interval.
79 * @param max Upper bound for the interval.
80 * @param startValue Start value to use.
81 * @param allowedSolution The kind of solutions that the root-finding algorithm may
82 * accept as solutions.
83 * @return A value where the function is zero.
84 * @throws org.apache.commons.math4.legacy.exception.MathIllegalArgumentException
85 * if the arguments do not satisfy the requirements specified by the solver.
86 * @throws org.apache.commons.math4.legacy.exception.TooManyEvaluationsException if
87 * the allowed number of evaluations is exceeded.
88 */
89 double solve(int maxEval, FUNC f, double min, double max, double startValue,
90 AllowedSolution allowedSolution);
91 }