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 package org.apache.commons.math.optimization;
18
19 import org.apache.commons.math.ConvergenceException;
20 import org.apache.commons.math.ConvergingAlgorithm;
21 import org.apache.commons.math.FunctionEvaluationException;
22 import org.apache.commons.math.analysis.UnivariateRealFunction;
23
24
25 /**
26 * Interface for (univariate real) optimization algorithms.
27 *
28 * @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $
29 * @since 2.0
30 */
31 public interface UnivariateRealOptimizer extends ConvergingAlgorithm {
32
33 /** Set the maximal number of functions evaluations.
34 * @param maxEvaluations maximal number of function evaluations
35 */
36 void setMaxEvaluations(int maxEvaluations);
37
38 /** Get the maximal number of functions evaluations.
39 * @return maximal number of functions evaluations
40 */
41 int getMaxEvaluations();
42
43 /** Get the number of evaluations of the objective function.
44 * <p>
45 * The number of evaluations corresponds to the last call to the
46 * {@link #optimize(UnivariateRealFunction, GoalType, double, double) optimize}
47 * method. It is 0 if the method has not been called yet.
48 * </p>
49 * @return number of evaluations of the objective function
50 */
51 int getEvaluations();
52
53 /**
54 * Find an optimum in the given interval.
55 * <p>
56 * An optimizer may require that the interval brackets a single optimum.
57 * </p>
58 * @param f the function to optimize.
59 * @param goalType type of optimization goal: either {@link GoalType#MAXIMIZE}
60 * or {@link GoalType#MINIMIZE}
61 * @param min the lower bound for the interval.
62 * @param max the upper bound for the interval.
63 * @return a value where the function is optimum
64 * @throws ConvergenceException if the maximum iteration count is exceeded
65 * or the optimizer detects convergence problems otherwise.
66 * @throws FunctionEvaluationException if an error occurs evaluating the
67 * function
68 * @throws IllegalArgumentException if min > max or the endpoints do not
69 * satisfy the requirements specified by the optimizer
70 */
71 double optimize(UnivariateRealFunction f, GoalType goalType,
72 double min, double max)
73 throws ConvergenceException, FunctionEvaluationException;
74
75 /**
76 * Find an optimum in the given interval, start at startValue.
77 * <p>
78 * An optimizer may require that the interval brackets a single optimum.
79 * </p>
80 * @param f the function to optimize.
81 * @param goalType type of optimization goal: either {@link GoalType#MAXIMIZE}
82 * or {@link GoalType#MINIMIZE}
83 * @param min the lower bound for the interval.
84 * @param max the upper bound for the interval.
85 * @param startValue the start value to use
86 * @return a value where the function is optimum
87 * @throws ConvergenceException if the maximum iteration count is exceeded
88 * or the optimizer detects convergence problems otherwise.
89 * @throws FunctionEvaluationException if an error occurs evaluating the
90 * function
91 * @throws IllegalArgumentException if min > max or the arguments do not
92 * satisfy the requirements specified by the optimizer
93 */
94 double optimize(UnivariateRealFunction f, GoalType goalType,
95 double min, double max, double startValue)
96 throws ConvergenceException, FunctionEvaluationException;
97
98 /**
99 * Get the result of the last run of the optimizer.
100 *
101 * @return the last result.
102 * @throws IllegalStateException if there is no result available, either
103 * because no result was yet computed or the last attempt failed.
104 */
105 double getResult();
106
107 /**
108 * Get the result of the last run of the optimizer.
109 *
110 * @return the value of the function at the last result.
111 * @throws IllegalStateException if there is no result available, either
112 * because no result was yet computed or the last attempt failed.
113 */
114 double getFunctionValue();
115
116 }