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.math3.analysis.solvers;
018    
019    import org.apache.commons.math3.analysis.UnivariateFunction;
020    
021    
022    /**
023     * Interface for (univariate real) rootfinding algorithms.
024     * Implementations will search for only one zero in the given interval.
025     *
026     * This class is not intended for use outside of the Apache Commons Math
027     * library, regular user should rely on more specific interfaces like
028     * {@link UnivariateSolver}, {@link PolynomialSolver} or {@link
029     * DifferentiableUnivariateSolver}.
030     * @param <FUNC> Type of function to solve.
031     *
032     * @since 3.0
033     * @version $Id: BaseUnivariateSolver.java 1364387 2012-07-22 18:14:11Z tn $
034     * @see UnivariateSolver
035     * @see PolynomialSolver
036     * @see DifferentiableUnivariateSolver
037     */
038    public interface BaseUnivariateSolver<FUNC extends UnivariateFunction> {
039        /**
040         * Get the maximum number of function evaluations.
041         *
042         * @return the maximum number of function evaluations.
043         */
044        int getMaxEvaluations();
045    
046        /**
047         * Get the number of evaluations of the objective function.
048         * The number of evaluations corresponds to the last call to the
049         * {@code optimize} method. It is 0 if the method has not been
050         * called yet.
051         *
052         * @return the number of evaluations of the objective function.
053         */
054        int getEvaluations();
055    
056        /**
057         * Get the absolute accuracy of the solver.  Solutions returned by the
058         * solver should be accurate to this tolerance, i.e., if &epsilon; is the
059         * absolute accuracy of the solver and {@code v} is a value returned by
060         * one of the {@code solve} methods, then a root of the function should
061         * exist somewhere in the interval ({@code v} - &epsilon;, {@code v} + &epsilon;).
062         *
063         * @return the absolute accuracy.
064         */
065        double getAbsoluteAccuracy();
066    
067        /**
068         * Get the relative accuracy of the solver.  The contract for relative
069         * accuracy is the same as {@link #getAbsoluteAccuracy()}, but using
070         * relative, rather than absolute error.  If &rho; is the relative accuracy
071         * configured for a solver and {@code v} is a value returned, then a root
072         * of the function should exist somewhere in the interval
073         * ({@code v} - &rho; {@code v}, {@code v} + &rho; {@code v}).
074         *
075         * @return the relative accuracy.
076         */
077        double getRelativeAccuracy();
078    
079        /**
080         * Get the function value accuracy of the solver.  If {@code v} is
081         * a value returned by the solver for a function {@code f},
082         * then by contract, {@code |f(v)|} should be less than or equal to
083         * the function value accuracy configured for the solver.
084         *
085         * @return the function value accuracy.
086         */
087        double getFunctionValueAccuracy();
088    
089        /**
090         * Solve for a zero root in the given interval.
091         * A solver may require that the interval brackets a single zero root.
092         * Solvers that do require bracketing should be able to handle the case
093         * where one of the endpoints is itself a root.
094         *
095         * @param maxEval Maximum number of evaluations.
096         * @param f Function to solve.
097         * @param min Lower bound for the interval.
098         * @param max Upper bound for the interval.
099         * @return a value where the function is zero.
100         * @throws org.apache.commons.math3.exception.MathIllegalArgumentException
101         * if the arguments do not satisfy the requirements specified by the solver.
102         * @throws org.apache.commons.math3.exception.TooManyEvaluationsException if
103         * the allowed number of evaluations is exceeded.
104         */
105        double solve(int maxEval, FUNC f, double min, double max);
106    
107        /**
108         * Solve for a zero in the given interval, start at {@code startValue}.
109         * A solver may require that the interval brackets a single zero root.
110         * Solvers that do require bracketing should be able to handle the case
111         * where one of the endpoints is itself a root.
112         *
113         * @param maxEval Maximum number of evaluations.
114         * @param f Function to solve.
115         * @param min Lower bound for the interval.
116         * @param max Upper bound for the interval.
117         * @param startValue Start value to use.
118         * @return a value where the function is zero.
119         * @throws org.apache.commons.math3.exception.MathIllegalArgumentException
120         * if the arguments do not satisfy the requirements specified by the solver.
121         * @throws org.apache.commons.math3.exception.TooManyEvaluationsException if
122         * the allowed number of evaluations is exceeded.
123         */
124        double solve(int maxEval, FUNC f, double min, double max, double startValue);
125    
126        /**
127         * Solve for a zero in the vicinity of {@code startValue}.
128         *
129         * @param f Function to solve.
130         * @param startValue Start value to use.
131         * @return a value where the function is zero.
132         * @param maxEval Maximum number of evaluations.
133         * @throws org.apache.commons.math3.exception.MathIllegalArgumentException
134         * if the arguments do not satisfy the requirements specified by the solver.
135         * @throws org.apache.commons.math3.exception.TooManyEvaluationsException if
136         * the allowed number of evaluations is exceeded.
137         */
138        double solve(int maxEval, FUNC f, double startValue);
139    }