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 * 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
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package org.apache.commons.math3.analysis.solvers;


Implements the Illinois method for root-finding (approximating a zero of a univariate real function). It is a modified Regula Falsi method. 
Like the Regula Falsi method, convergence is guaranteed by
maintaining a bracketed solution. The Illinois method however,
should converge much faster than the original Regula Falsi
method. Furthermore, this implementation of the Illinois method
should not suffer from the same implementation issues as the Regula
Falsi method, which may fail to convergence in certain cases.
The Illinois method assumes that the function is continuous,
but not necessarily smooth.
Implementation based on the following article: M. Dowell and P. Jarratt,
A modified regula falsi method for computing the root of an
equation, BIT Numerical Mathematics, volume 11, number 2,
pages 168-174, Springer, 1971.
Since:
3.0/**
 * Implements the <em>Illinois</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>Illinois</em> method however,
 * should converge much faster than the original <em>Regula Falsi</em>
 * method. Furthermore, this implementation of the <em>Illinois</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.</p>
 *
 * <p>The <em>Illinois</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>A modified regula falsi method for computing the root of an
 * equation</em>, BIT Numerical Mathematics, volume 11, number 2,
 * pages 168-174, Springer, 1971.</p>
 *
 * @since 3.0
 */
public class IllinoisSolver extends BaseSecantSolver {

    
Construct a solver with default accuracy (1e-6). /** Construct a solver with default accuracy (1e-6). */
    public IllinoisSolver() {
        super(DEFAULT_ABSOLUTE_ACCURACY, Method.ILLINOIS);
    }

    
Construct a solver.
Params:
absoluteAccuracy – Absolute accuracy./**
     * Construct a solver.
     *
     * @param absoluteAccuracy Absolute accuracy.
     */
    public IllinoisSolver(final double absoluteAccuracy) {
        super(absoluteAccuracy, Method.ILLINOIS);
    }

    
Construct a solver.
Params:
relativeAccuracy – Relative accuracy.
absoluteAccuracy – Absolute accuracy./**
     * Construct a solver.
     *
     * @param relativeAccuracy Relative accuracy.
     * @param absoluteAccuracy Absolute accuracy.
     */
    public IllinoisSolver(final double relativeAccuracy,
                          final double absoluteAccuracy) {
        super(relativeAccuracy, absoluteAccuracy, Method.ILLINOIS);
    }

    
Construct a solver.
Params:
relativeAccuracy – Relative accuracy.
absoluteAccuracy – Absolute accuracy.
functionValueAccuracy – Maximum function value error./**
     * Construct a solver.
     *
     * @param relativeAccuracy Relative accuracy.
     * @param absoluteAccuracy Absolute accuracy.
     * @param functionValueAccuracy Maximum function value error.
     */
    public IllinoisSolver(final double relativeAccuracy,
                          final double absoluteAccuracy,
                          final double functionValueAccuracy) {
        super(relativeAccuracy, absoluteAccuracy, functionValueAccuracy, Method.PEGASUS);
    }
}