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geant4/source/global/HEPNumerics/include/G4SimpleIntegration.hh
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// $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