Gabriele Cosmo
90 lines
3.7 KiB
C++
90 lines
3.7 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// G4SimpleIntegration
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//
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// Class description:
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//
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// Class for realisation of simple numerical methodes for integration of
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// functions with signature: double f(double). The methods based mainly on
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// algorithms given in the book:
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// An introduction to NUMERICAL METHODS IN C++,
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// B.H. Flowers, Claredon Press, Oxford, 1995.
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// Author: V.Grichine, 26.03.1997
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// --------------------------------------------------------------------
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#ifndef G4SIMPLEINTEGRATION_HH
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#define G4SIMPLEINTEGRATION_HH 1
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#include "G4Types.hh"
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typedef G4double (*function)(G4double);
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class G4SimpleIntegration
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{
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public:
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explicit G4SimpleIntegration(function pFunction);
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G4SimpleIntegration(function pFunction, G4double pTolerance);
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~G4SimpleIntegration();
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G4SimpleIntegration(const G4SimpleIntegration&) = delete;
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G4SimpleIntegration& operator=(const G4SimpleIntegration&) = delete;
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// Private copy constructor and assignment operator.
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// Simple integration methods:
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// Trapezoidal, MidPoint, Gauss and Simpson(double a,double b,int n)
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// - integrate function pointed by fFunction from a to b by n iterations,
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// i.e. with Step (b-a)/n according to the correspondent method.
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G4double Trapezoidal(G4double xInitial, G4double xFinal,
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G4int iterationNumber);
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G4double MidPoint(G4double xInitial, G4double xFinal, G4int iterationNumber);
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G4double Gauss(G4double xInitial, G4double xFinal, G4int iterationNumber);
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G4double Simpson(G4double xInitial, G4double xFinal, G4int iterationNumber);
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// Adaptive Gauss integration with accuracy ~ fTolerance
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G4double AdaptGaussIntegration(G4double xInitial, G4double xFinal);
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// Integrate function from a to be with accuracy <= fTolerance
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protected:
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G4double Gauss(G4double xInitial, G4double xFinal);
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void AdaptGauss(G4double xInitial, G4double xFinal, G4double& sum,
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G4int& depth);
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private:
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function fFunction; // pointer to the function to be integrated
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G4double fTolerance = 0.0001; // accuracy of integration
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const G4int fMaxDepth = 100; // constant maximum iteration depth
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};
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#endif
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