| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.math.analysis.solvers; |
| |
| import org.apache.commons.math.FunctionEvaluationException; |
| import org.apache.commons.math.MaxIterationsExceededException; |
| import org.apache.commons.math.analysis.UnivariateRealFunction; |
| import org.apache.commons.math.util.FastMath; |
| |
| /** |
| * Implements the <a href="http://mathworld.wolfram.com/Bisection.html"> |
| * bisection algorithm</a> for finding zeros of univariate real functions. |
| * <p> |
| * The function should be continuous but not necessarily smooth.</p> |
| * |
| * @version $Revision: 1070725 $ $Date: 2011-02-15 02:31:12 +0100 (mar. 15 févr. 2011) $ |
| */ |
| public class BisectionSolver extends UnivariateRealSolverImpl { |
| |
| /** |
| * Construct a solver for the given function. |
| * |
| * @param f function to solve. |
| * @deprecated as of 2.0 the function to solve is passed as an argument |
| * to the {@link #solve(UnivariateRealFunction, double, double)} or |
| * {@link UnivariateRealSolverImpl#solve(UnivariateRealFunction, double, double, double)} |
| * method. |
| */ |
| @Deprecated |
| public BisectionSolver(UnivariateRealFunction f) { |
| super(f, 100, 1E-6); |
| } |
| |
| /** |
| * Construct a solver. |
| * |
| */ |
| public BisectionSolver() { |
| super(100, 1E-6); |
| } |
| |
| /** {@inheritDoc} */ |
| @Deprecated |
| public double solve(double min, double max, double initial) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| return solve(f, min, max); |
| } |
| |
| /** {@inheritDoc} */ |
| @Deprecated |
| public double solve(double min, double max) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| return solve(f, min, max); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * @deprecated in 2.2 (to be removed in 3.0). |
| */ |
| @Deprecated |
| public double solve(final UnivariateRealFunction f, double min, double max, double initial) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| return solve(f, min, max); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public double solve(int maxEval, final UnivariateRealFunction f, double min, double max, double initial) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| return solve(maxEval, f, min, max); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public double solve(int maxEval, final UnivariateRealFunction f, double min, double max) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| setMaximalIterationCount(maxEval); |
| return solve(f, min, max); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * @deprecated in 2.2 (to be removed in 3.0). |
| */ |
| @Deprecated |
| public double solve(final UnivariateRealFunction f, double min, double max) |
| throws MaxIterationsExceededException, FunctionEvaluationException { |
| |
| clearResult(); |
| verifyInterval(min,max); |
| double m; |
| double fm; |
| double fmin; |
| |
| int i = 0; |
| while (i < maximalIterationCount) { |
| m = UnivariateRealSolverUtils.midpoint(min, max); |
| fmin = f.value(min); |
| fm = f.value(m); |
| |
| if (fm * fmin > 0.0) { |
| // max and m bracket the root. |
| min = m; |
| } else { |
| // min and m bracket the root. |
| max = m; |
| } |
| |
| if (FastMath.abs(max - min) <= absoluteAccuracy) { |
| m = UnivariateRealSolverUtils.midpoint(min, max); |
| setResult(m, i); |
| return m; |
| } |
| ++i; |
| } |
| |
| throw new MaxIterationsExceededException(maximalIterationCount); |
| } |
| } |