    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.math.optimization;
    018
    019    import org.apache.commons.math.ConvergenceException;
    020    import org.apache.commons.math.FunctionEvaluationException;
    021    import org.apache.commons.math.ConvergingAlgorithm;
    022    import org.apache.commons.math.analysis.UnivariateRealFunction;
    023
    024
    025    /**
    026     * Interface for (univariate real) optimization algorithms.
    027     *
    028     * @version $Revision: 1073658 $ $Date: 2011-02-23 10:45:42 +0100 (mer. 23 f??vr. 2011) $
    029     * @since 2.0
    030     */
    031    public interface UnivariateRealOptimizer extends ConvergingAlgorithm {
    032
    033        /** Set the maximal number of functions evaluations.
    034         * @param maxEvaluations maximal number of function evaluations
    035         */
    036        void setMaxEvaluations(int maxEvaluations);
    037
    038        /** Get the maximal number of functions evaluations.
    039         * @return the maximal number of functions evaluations.
    040         */
    041        int getMaxEvaluations();
    042
    043        /** Get the number of evaluations of the objective function.
    044         * <p>
    045         * The number of evaluations corresponds to the last call to the
    046         * {@link #optimize(UnivariateRealFunction, GoalType, double, double) optimize}
    047         * method. It is 0 if the method has not been called yet.
    048         * </p>
    049         * @return the number of evaluations of the objective function.
    050         */
    051        int getEvaluations();
    052
    053        /**
    054         * Find an optimum in the given interval.
    055         * <p>
    056         * An optimizer may require that the interval brackets a single optimum.
    057         * </p>
    058         * @param f the function to optimize.
    059         * @param goalType type of optimization goal: either {@link GoalType#MAXIMIZE}
    060         * or {@link GoalType#MINIMIZE}.
    061         * @param min the lower bound for the interval.
    062         * @param max the upper bound for the interval.
    063         * @return a value where the function is optimum.
    064         * @throws ConvergenceException if the maximum iteration count is exceeded
    065         * or the optimizer detects convergence problems otherwise.
    066         * @throws FunctionEvaluationException if an error occurs evaluating the function.
    067         * @throws IllegalArgumentException if min > max or the endpoints do not
    068         * satisfy the requirements specified by the optimizer.
    069         */
    070        double optimize(UnivariateRealFunction f, GoalType goalType,
    071                        double min, double max)
    072            throws ConvergenceException, FunctionEvaluationException;
    073
    074        /**
    075         * Find an optimum in the given interval, start at startValue.
    076         * <p>
    077         * An optimizer may require that the interval brackets a single optimum.
    078         * </p>
    079         * @param f the function to optimize.
    080         * @param goalType type of optimization goal: either {@link GoalType#MAXIMIZE}
    081         * or {@link GoalType#MINIMIZE}.
    082         * @param min the lower bound for the interval.
    083         * @param max the upper bound for the interval.
    084         * @param startValue the start value to use.
    085         * @return a value where the function is optimum.
    086         * @throws ConvergenceException if the maximum iteration count is exceeded
    087         * or the optimizer detects convergence problems otherwise.
    088         * @throws FunctionEvaluationException if an error occurs evaluating the function.
    089         * @throws IllegalArgumentException if min > max or the arguments do not
    090         * satisfy the requirements specified by the optimizer.
    091         * @throws IllegalStateException if there are no data.
    092         */
    093        double optimize(UnivariateRealFunction f, GoalType goalType,
    094                        double min, double max, double startValue)
    095            throws ConvergenceException, FunctionEvaluationException;
    096
    097        /**
    098         * Get the result of the last run of the optimizer.
    099         *
    100         * @return the optimum.
    101         * @throws IllegalStateException if there is no result available, either
    102         * because no result was yet computed or the last attempt failed.
    103         */
    104        double getResult();
    105
    106        /**
    107         * Get the result of the last run of the optimizer.
    108         *
    109         * @return the value of the function at the optimum.
    110         * @throws FunctionEvaluationException if an error occurs evaluating the function.
    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() throws FunctionEvaluationException;
    115
    116    }