| /* |
| * 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.math4.legacy.analysis.solvers; |
| |
| /** |
| * Implements the <em>Pegasus</em> method for root-finding (approximating |
| * a zero of a univariate real function). It is a modified |
| * {@link RegulaFalsiSolver <em>Regula Falsi</em>} method. |
| * |
| * <p>Like the <em>Regula Falsi</em> method, convergence is guaranteed by |
| * maintaining a bracketed solution. The <em>Pegasus</em> method however, |
| * should converge much faster than the original <em>Regula Falsi</em> |
| * method. Furthermore, this implementation of the <em>Pegasus</em> method |
| * should not suffer from the same implementation issues as the <em>Regula |
| * Falsi</em> method, which may fail to convergence in certain cases. Also, |
| * the <em>Pegasus</em> method should converge faster than the |
| * {@link IllinoisSolver <em>Illinois</em>} method, another <em>Regula |
| * Falsi</em>-based method.</p> |
| * |
| * <p>The <em>Pegasus</em> method assumes that the function is continuous, |
| * but not necessarily smooth.</p> |
| * |
| * <p>Implementation based on the following article: M. Dowell and P. Jarratt, |
| * <em>The "Pegasus" method for computing the root of an equation</em>, |
| * BIT Numerical Mathematics, volume 12, number 4, pages 503-508, Springer, |
| * 1972.</p> |
| * |
| * @since 3.0 |
| */ |
| public class PegasusSolver extends BaseSecantSolver { |
| |
| /** Construct a solver with default accuracy (1e-6). */ |
| public PegasusSolver() { |
| super(DEFAULT_ABSOLUTE_ACCURACY, Method.PEGASUS); |
| } |
| |
| /** |
| * Construct a solver. |
| * |
| * @param absoluteAccuracy Absolute accuracy. |
| */ |
| public PegasusSolver(final double absoluteAccuracy) { |
| super(absoluteAccuracy, Method.PEGASUS); |
| } |
| |
| /** |
| * Construct a solver. |
| * |
| * @param relativeAccuracy Relative accuracy. |
| * @param absoluteAccuracy Absolute accuracy. |
| */ |
| public PegasusSolver(final double relativeAccuracy, |
| final double absoluteAccuracy) { |
| super(relativeAccuracy, absoluteAccuracy, Method.PEGASUS); |
| } |
| |
| /** |
| * Construct a solver. |
| * |
| * @param relativeAccuracy Relative accuracy. |
| * @param absoluteAccuracy Absolute accuracy. |
| * @param functionValueAccuracy Maximum function value error. |
| */ |
| public PegasusSolver(final double relativeAccuracy, |
| final double absoluteAccuracy, |
| final double functionValueAccuracy) { |
| super(relativeAccuracy, absoluteAccuracy, functionValueAccuracy, Method.PEGASUS); |
| } |
| } |