Coverage Report - org.apache.commons.math.analysis.BisectionSolver

Classes in this File	Line Coverage	Branch Coverage	Complexity
BisectionSolver	90%	100%	2.6666666666666665;2.667

1		/*
2		* Copyright 2003-2004 The Apache Software Foundation.
3		*
4		* Licensed under the Apache License, Version 2.0 (the "License");
5		* you may not use this file except in compliance with the License.
6		* You may obtain a copy of the License at
7		*
8		* http://www.apache.org/licenses/LICENSE-2.0
9		*
10		* Unless required by applicable law or agreed to in writing, software
11		* distributed under the License is distributed on an "AS IS" BASIS,
12		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13		* See the License for the specific language governing permissions and
14		* limitations under the License.
15		*/
16		package org.apache.commons.math.analysis;
17
18		import org.apache.commons.math.FunctionEvaluationException;
19		import org.apache.commons.math.ConvergenceException;
20
21		/**
22		* Implements the <a href="http://mathworld.wolfram.com/Bisection.html">
23		* bisection algorithm</a> for finding zeros of univariate real functions.
24		* <p>
25		* The function should be continuous but not necessarily smooth.
26		*
27		* @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $
28		*/
29		public class BisectionSolver extends UnivariateRealSolverImpl {
30
31		/** Serializable version identifier */
32		static final long serialVersionUID = 7137520585963699578L;
33
34		/**
35		* Construct a solver for the given function.
36		*
37		* @param f function to solve.
38		*/
39		public BisectionSolver(UnivariateRealFunction f) {
40	30	super(f, 100, 1E-6);
41	28	}
42
43		/**
44		* Find a zero in the given interval.
45		*
46		* @param min the lower bound for the interval.
47		* @param max the upper bound for the interval.
48		* @param initial the start value to use (ignored).
49		* @return the value where the function is zero
50		* @throws ConvergenceException the maximum iteration count is exceeded
51		* @throws FunctionEvaluationException if an error occurs evaluating
52		* the function
53		* @throws IllegalArgumentException if min is not less than max
54		*/
55		public double solve(double min, double max, double initial)
56		throws ConvergenceException, FunctionEvaluationException {
57
58	0	return solve(min, max);
59		}
60
61		/**
62		* Find a zero root in the given interval.
63		*
64		* @param min the lower bound for the interval
65		* @param max the upper bound for the interval
66		* @return the value where the function is zero
67		* @throws ConvergenceException if the maximum iteration count is exceeded.
68		* @throws FunctionEvaluationException if an error occurs evaluating the
69		* function
70		* @throws IllegalArgumentException if min is not less than max
71		*/
72		public double solve(double min, double max) throws ConvergenceException,
73		FunctionEvaluationException {
74
75	92	clearResult();
76	92	verifyInterval(min,max);
77		double m;
78		double fm;
79		double fmin;
80
81	92	int i = 0;
82	1812	while (i < maximalIterationCount) {
83	1812	m = UnivariateRealSolverUtils.midpoint(min, max);
84	1812	fmin = f.value(min);
85	1812	fm = f.value(m);
86
87	1812	if (fm * fmin > 0.0) {
88		// max and m bracket the root.
89	1276	min = m;
90	1276	fmin = fm;
91		} else {
92		// min and m bracket the root.
93	536	max = m;
94		}
95
96	1812	if (Math.abs(max - min) <= absoluteAccuracy) {
97	92	m = UnivariateRealSolverUtils.midpoint(min, max);
98	92	setResult(m, i);
99	92	return m;
100		}
101	1720	++i;
102		}
103
104	0	throw new ConvergenceException
105		("Maximum number of iterations exceeded: " + maximalIterationCount);
106		}
107		}