Christoph Ruegg
13 years ago
5 changed files with 78 additions and 89 deletions
@ -1,78 +0,0 @@ |
|||
// <copyright file="Bracketing.cs" company="Math.NET">
|
|||
// Math.NET Numerics, part of the Math.NET Project
|
|||
// http://numerics.mathdotnet.com
|
|||
// http://github.com/mathnet/mathnet-numerics
|
|||
// http://mathnetnumerics.codeplex.com
|
|||
//
|
|||
// Copyright (c) 2009-2013 Math.NET
|
|||
//
|
|||
// Permission is hereby granted, free of charge, to any person
|
|||
// obtaining a copy of this software and associated documentation
|
|||
// files (the "Software"), to deal in the Software without
|
|||
// restriction, including without limitation the rights to use,
|
|||
// copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|||
// copies of the Software, and to permit persons to whom the
|
|||
// Software is furnished to do so, subject to the following
|
|||
// conditions:
|
|||
//
|
|||
// The above copyright notice and this permission notice shall be
|
|||
// included in all copies or substantial portions of the Software.
|
|||
//
|
|||
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|||
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
|
|||
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|||
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
|||
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
|||
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|||
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
|||
// OTHER DEALINGS IN THE SOFTWARE.
|
|||
// </copyright>
|
|||
|
|||
using System; |
|||
using MathNet.Numerics.Properties; |
|||
|
|||
namespace MathNet.Numerics.RootFinding |
|||
{ |
|||
public static class Bracketing |
|||
{ |
|||
/// <summary>Detect a range containing at least one root.</summary>
|
|||
/// <param name="f">The function to detect roots from.</param>
|
|||
/// <param name="lowerBound">Lower value of the range.</param>
|
|||
/// <param name="upperBound">Upper value of the range</param>
|
|||
/// <param name="factor">The growing factor of research. Usually 1.6.</param>
|
|||
/// <param name="maxIterations">Maximum number of iterations. Usually 50.</param>
|
|||
/// <returns>True if the bracketing operation succeeded, false otherwise.</returns>
|
|||
/// <remarks>This iterative methods stops when two values with opposite signs are found.</remarks>
|
|||
public static bool Expand(Func<double, double> f, ref double lowerBound, ref double upperBound, double factor = 1.6, int maxIterations = 50) |
|||
{ |
|||
if (lowerBound >= upperBound) |
|||
{ |
|||
throw new ArgumentOutOfRangeException("upperBound", string.Format(Resources.ArgumentOutOfRangeGreater, "xmax", "xmin")); |
|||
} |
|||
|
|||
double fmin = f(lowerBound); |
|||
double fmax = f(upperBound); |
|||
|
|||
for (int i = 0; i < maxIterations; i++) |
|||
{ |
|||
if (Math.Sign(fmin) != Math.Sign(fmax)) |
|||
{ |
|||
return true; |
|||
} |
|||
|
|||
if (Math.Abs(fmin) < Math.Abs(fmax)) |
|||
{ |
|||
lowerBound += factor*(lowerBound - upperBound); |
|||
fmin = f(lowerBound); |
|||
} |
|||
else |
|||
{ |
|||
upperBound += factor*(upperBound - lowerBound); |
|||
fmax = f(upperBound); |
|||
} |
|||
} |
|||
|
|||
return false; |
|||
} |
|||
} |
|||
} |
|||
Loading…
Reference in new issue