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 //! This class implements a combination of Newton-Raphson and bissection
0030 //! methods to find the root of the function between two bounds.
0031 //! Knowledge of the derivative is required.
0032 class math_BissecNewton
0033 {
0034 public:
0035   DEFINE_STANDARD_ALLOC
0036
0037   //! Constructor.
0038   //! @param theXTolerance - algorithm tolerance.
0039   Standard_EXPORT math_BissecNewton(const double theXTolerance);
0040
0041   //! A combination of Newton-Raphson and bissection methods is done to find
0042   //! the root of the function F between the bounds Bound1 and Bound2
0043   //! on the function F.
0044   //! The tolerance required on the root is given by TolX.
0045   //! The solution is found when:
0046   //! abs(Xi - Xi-1) <= TolX and F(Xi) * F(Xi-1) <= 0
0047   //! The maximum number of iterations allowed is given by NbIterations.
0048   Standard_EXPORT void Perform(math_FunctionWithDerivative& F,
0049                                const double                 Bound1,
0050                                const double                 Bound2,
0051                                const int                    NbIterations = 100);
0052
0053   //! This method is called at the end of each iteration to check if the
0054   //! solution has been found.
0055   //! It can be redefined in a sub-class to implement a specific test to
0056   //! stop the iterations.
0057   virtual bool IsSolutionReached(math_FunctionWithDerivative& theFunction);
0058
0059   //! Tests is the root has been successfully found.
0060   bool IsDone() const;
0061
0062   //! returns the value of the root.
0063   //! Exception NotDone is raised if the minimum was not found.
0064   double Root() const;
0065
0066   //! returns the value of the derivative at the root.
0067   //! Exception NotDone is raised if the minimum was not found.
0068   double Derivative() const;
0069
0070   //! returns the value of the function at the root.
0071   //! Exception NotDone is raised if the minimum was not found.
0072   double Value() const;
0073
0074   //! Prints on the stream o information on the current state
0075   //! of the object.
0076   //! Is used to redefine the operator <<.
0077   Standard_EXPORT void Dump(Standard_OStream& o) const;
0078
0079   //! Destructor
0080   Standard_EXPORT virtual ~math_BissecNewton();
0081
0082 protected:
0083   math_Status TheStatus;
0084   double      XTol;
0085   double      x;
0086   double      dx;
0087   double      f;
0088   double      df;
0089
0090 private:
0091   bool Done;
0092 };
0093
0094 #include <math_BissecNewton.lxx>
0095
0096 #endif // _math_BissecNewton_HeaderFile