G4SimpleIntegration.hh

Go to the documentation of this file.

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
//
// $Id: G4SimpleIntegration.hh 69546 2013-05-08 09:50:34Z gcosmo $
//
// Class description:
//
// Class for realisation of simple numerical methodes for integration of
// functions with signature: double f(double). The methods based mainly on
// algorithms given in the book :
//   An introduction to NUMERICAL METHODS IN C++,
//   B.H. Flowers, Claredon Press, Oxford, 1995.
//
// --------------------------- Member data ----------------------------
//
//   fFunction       - pointer to the function to be integrated
//   fTolerance      - accuracy of integration in Adaptive Gauss method
//   fMaxDepth = 100 - constant maximum iteration depth for
//                     Adaptive Gauss method
//
// --------------------------- Methods --------------------------------
//
//   Trapezoidal, MidPoint, Gauss and Simpson(double a,double b,int n)
//   - integrate function pointed by fFunction from a to b by n iterations,
//     i.e. with Step (b-a)/n according to the correspondent method.
//
//   AdaptGausIntegration(double a, double b)
//   - integrate function from a to be with accuracy <= fTolerance 

// ----------------------------- History ------------------------------ 
//
//  26.03.97   V.Grichine ( Vladimir.Grichine@cern.ch )

#ifndef G4SIMPLEINTEGRATION_HH
#define G4SIMPLEINTEGRATION_HH

#include "G4Types.hh"

typedef G4double (*function)(G4double) ;

class G4SimpleIntegration
{
  public:

       explicit G4SimpleIntegration( function pFunction ) ;
       
       G4SimpleIntegration( function pFunction,
                            G4double pTolerance ) ;
       
      ~G4SimpleIntegration() ;
       
       // Simple integration methods
       
       G4double Trapezoidal(G4double xInitial,
                            G4double xFinal,
                            G4int iterationNumber ) ;

       G4double    MidPoint(G4double xInitial,
                            G4double xFinal,
                            G4int iterationNumber ) ;

       G4double       Gauss(G4double xInitial,
                            G4double xFinal,
                            G4int iterationNumber ) ;

       G4double     Simpson(G4double xInitial,
                            G4double xFinal,
                            G4int iterationNumber ) ;

       // Adaptive Gauss integration with accuracy ~ fTolerance

       G4double       AdaptGaussIntegration( G4double xInitial,
                                             G4double xFinal   ) ;
       
  protected:

       G4double       Gauss( G4double xInitial,
                             G4double xFinal   ) ;

       void      AdaptGauss( G4double xInitial,
                             G4double xFinal,
                             G4double& sum,
                             G4int& depth      ) ;
  private:

       G4SimpleIntegration(const G4SimpleIntegration&);
       G4SimpleIntegration& operator=(const G4SimpleIntegration&);
         // Private copy constructor and assignment operator.

  private:

        function fFunction ;
        G4double fTolerance ;
        const G4int fMaxDepth ;
};

#endif