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 package org.hipparchus.optim.univariate;
23
24 import org.hipparchus.analysis.UnivariateFunction;
25 import org.hipparchus.exception.MathIllegalStateException;
26 import org.hipparchus.optim.BaseOptimizer;
27 import org.hipparchus.optim.ConvergenceChecker;
28 import org.hipparchus.optim.OptimizationData;
29 import org.hipparchus.optim.nonlinear.scalar.GoalType;
30
31 /**
32 * Base class for a univariate scalar function optimizer.
33 *
34 */
35 public abstract class UnivariateOptimizer
36 extends BaseOptimizer<UnivariatePointValuePair> {
37 /** Objective function. */
38 private UnivariateFunction function;
39 /** Type of optimization. */
40 private GoalType goal;
41 /** Initial guess. */
42 private double start;
43 /** Lower bound. */
44 private double min;
45 /** Upper bound. */
46 private double max;
47
48 /** Simple constructor.
49 * @param checker Convergence checker.
50 */
51 protected UnivariateOptimizer(ConvergenceChecker<UnivariatePointValuePair> checker) {
52 super(checker);
53 }
54
55 /**
56 * {@inheritDoc}
57 *
58 * @param optData Optimization data. In addition to those documented in
59 * {@link BaseOptimizer#parseOptimizationData(OptimizationData[])
60 * BaseOptimizer}, this method will register the following data:
61 * <ul>
62 * <li>{@link GoalType}</li>
63 * <li>{@link SearchInterval}</li>
64 * <li>{@link UnivariateObjectiveFunction}</li>
65 * </ul>
66 * @return {@inheritDoc}
67 * @throws MathIllegalStateException if the maximal number of
68 * evaluations is exceeded.
69 */
70 @Override
71 public UnivariatePointValuePair optimize(OptimizationData... optData)
72 throws MathIllegalStateException {
73 // Perform computation.
74 return super.optimize(optData);
75 }
76
77 /** Get optimization type.
78 * @return the optimization type
79 */
80 public GoalType getGoalType() {
81 return goal;
82 }
83
84 /**
85 * Scans the list of (required and optional) optimization data that
86 * characterize the problem.
87 *
88 * @param optData Optimization data.
89 * The following data will be looked for:
90 * <ul>
91 * <li>{@link GoalType}</li>
92 * <li>{@link SearchInterval}</li>
93 * <li>{@link UnivariateObjectiveFunction}</li>
94 * </ul>
95 */
96 @Override
97 protected void parseOptimizationData(OptimizationData... optData) {
98 // Allow base class to register its own data.
99 super.parseOptimizationData(optData);
100
101 // The existing values (as set by the previous call) are reused if
102 // not provided in the argument list.
103 for (OptimizationData data : optData) {
104 if (data instanceof SearchInterval) {
105 final SearchInterval interval = (SearchInterval) data;
106 min = interval.getMin();
107 max = interval.getMax();
108 start = interval.getStartValue();
109 continue;
110 }
111 if (data instanceof UnivariateObjectiveFunction) {
112 function = ((UnivariateObjectiveFunction) data).getObjectiveFunction();
113 continue;
114 }
115 if (data instanceof GoalType) {
116 goal = (GoalType) data;
117 continue;
118 }
119 }
120 }
121
122 /** Get initial guess.
123 * @return the initial guess
124 */
125 public double getStartValue() {
126 return start;
127 }
128 /** Get lower bounds.
129 * @return the lower bounds
130 */
131 public double getMin() {
132 return min;
133 }
134 /** Get upper bounds.
135 * @return the upper bounds
136 */
137 public double getMax() {
138 return max;
139 }
140
141 /**
142 * Computes the objective function value.
143 * This method <em>must</em> be called by subclasses to enforce the
144 * evaluation counter limit.
145 *
146 * @param x Point at which the objective function must be evaluated.
147 * @return the objective function value at the specified point.
148 * @throws MathIllegalStateException if the maximal number of
149 * evaluations is exceeded.
150 */
151 protected double computeObjectiveValue(double x) {
152 super.incrementEvaluationCount();
153 return function.value(x);
154 }
155 }