include/opencascade/math_BissecNewton.hxx

0001 // Created on: 1991-03-14
0002 // Created by: Laurent PAINNOT
0003 // Copyright (c) 1991-1999 Matra Datavision
0004 // Copyright (c) 1999-2014 OPEN CASCADE SAS
0005 //
0006 // This file is part of Open CASCADE Technology software library.
0007 //
0008 // This library is free software; you can redistribute it and/or modify it under
0009 // the terms of the GNU Lesser General Public License version 2.1 as published
0010 // by the Free Software Foundation, with special exception defined in the file
0011 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
0012 // distribution for complete text of the license and disclaimer of any warranty.
0013 //
0014 // Alternatively, this file may be used under the terms of Open CASCADE
0015 // commercial license or contractual agreement.
0016
0017 #ifndef _math_BissecNewton_HeaderFile
0018 #define _math_BissecNewton_HeaderFile
0019
0020 #include <Standard.hxx>
0021 #include <Standard_DefineAlloc.hxx>
0022 #include <Standard_Handle.hxx>
0023
0024 #include <math_Status.hxx>
0025 #include <Standard_Real.hxx>
0026 #include <Standard_OStream.hxx>
0027 class math_FunctionWithDerivative;
0028
0029
0030
0031 //! This class implements a combination of Newton-Raphson and bissection
0032 //! methods to find the root of the function between two bounds.
0033 //! Knowledge of the derivative is required.
0034 class math_BissecNewton
0035 {
0036 public:
0037
0038   DEFINE_STANDARD_ALLOC
0039
0040
0041   //! Constructor.
0042   //! @param theXTolerance - algorithm tolerance.
0043   Standard_EXPORT math_BissecNewton(const Standard_Real theXTolerance);
0044
0045
0046   //! A combination of Newton-Raphson and bissection methods is done to find
0047   //! the root of the function F between the bounds Bound1 and Bound2
0048   //! on the function F.
0049   //! The tolerance required on the root is given by TolX.
0050   //! The solution is found when:
0051   //! abs(Xi - Xi-1) <= TolX and F(Xi) * F(Xi-1) <= 0
0052   //! The maximum number of iterations allowed is given by NbIterations.
0053   Standard_EXPORT void Perform (math_FunctionWithDerivative& F, const Standard_Real Bound1, const Standard_Real Bound2, const Standard_Integer NbIterations = 100);
0054
0055
0056   //! This method is called at the end of each iteration to check if the
0057   //! solution has been found.
0058   //! It can be redefined in a sub-class to implement a specific test to
0059   //! stop the iterations.
0060     virtual Standard_Boolean IsSolutionReached (math_FunctionWithDerivative& theFunction);
0061
0062   //! Tests is the root has been successfully found.
0063     Standard_Boolean IsDone() const;
0064
0065   //! returns the value of the root.
0066   //! Exception NotDone is raised if the minimum was not found.
0067     Standard_Real Root() const;
0068
0069   //! returns the value of the derivative at the root.
0070   //! Exception NotDone is raised if the minimum was not found.
0071     Standard_Real Derivative() const;
0072
0073   //! returns the value of the function at the root.
0074   //! Exception NotDone is raised if the minimum was not found.
0075     Standard_Real Value() const;
0076
0077   //! Prints on the stream o information on the current state
0078   //! of the object.
0079   //! Is used to redifine the operator <<.
0080   Standard_EXPORT void Dump (Standard_OStream& o) const;
0081
0082   //! Destructor
0083   Standard_EXPORT virtual ~math_BissecNewton();
0084
0085
0086
0087
0088 protected:
0089
0090
0091
0092   math_Status TheStatus;
0093   Standard_Real XTol;
0094   Standard_Real x;
0095   Standard_Real dx;
0096   Standard_Real f;
0097   Standard_Real df;
0098
0099
0100 private:
0101
0102
0103
0104   Standard_Boolean Done;
0105
0106
0107 };
0108
0109
0110 #include <math_BissecNewton.lxx>
0111
0112
0113
0114
0115
0116 #endif // _math_BissecNewton_HeaderFile