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 /** The kinds of solutions that a {@link BracketedUnivariateSolver
27 * (bracketed univariate real) root-finding algorithm} may accept as solutions.
28 * This basically controls whether or not under-approximations and
29 * over-approximations are allowed.
30 *
31 * <p>If all solutions are accepted ({@link #ANY_SIDE}), then the solution
32 * that the root-finding algorithm returns for a given root may be equal to the
33 * actual root, but it may also be an approximation that is slightly smaller
34 * or slightly larger than the actual root. Root-finding algorithms generally
35 * only guarantee that the returned solution is within the requested
36 * tolerances. In certain cases however, it may be necessary to guarantee
37 * that a solution is returned that lies on a specific side the solution.</p>
38 *
39 * @see BracketedUnivariateSolver
40 */
41 public enum AllowedSolution {
42 /** There are no additional side restriction on the solutions for
43 * root-finding. That is, both under-approximations and over-approximations
44 * are allowed. So, if a function f(x) has a root at x = x0, then the
45 * root-finding result s may be smaller than x0, equal to x0, or greater
46 * than x0.
47 */
48 ANY_SIDE,
49
50 /** Only solutions that are less than or equal to the actual root are
51 * acceptable as solutions for root-finding. In other words,
52 * over-approximations are not allowed. So, if a function f(x) has a root
53 * at x = x0, then the root-finding result s must satisfy s <= x0.
54 */
55 LEFT_SIDE,
56
57 /** Only solutions that are greater than or equal to the actual root are
58 * acceptable as solutions for root-finding. In other words,
59 * under-approximations are not allowed. So, if a function f(x) has a root
60 * at x = x0, then the root-finding result s must satisfy s >= x0.
61 */
62 RIGHT_SIDE,
63
64 /** Only solutions for which values are less than or equal to zero are
65 * acceptable as solutions for root-finding. So, if a function f(x) has
66 * a root at x = x0, then the root-finding result s must satisfy f(s) <= 0.
67 */
68 BELOW_SIDE,
69
70 /** Only solutions for which values are greater than or equal to zero are
71 * acceptable as solutions for root-finding. So, if a function f(x) has
72 * a root at x = x0, then the root-finding result s must satisfy f(s) >= 0.
73 */
74 ABOVE_SIDE;
75
76 }