Gabriele Cosmo
77 lines
3.3 KiB
C++
77 lines
3.3 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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// G4VGaussianQuadrature
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//
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// Class description:
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//
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// Base Class for realisation of numerical methodes for integration of functions
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// with signature double f(double) by Gaussian quadrature methods
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// Roots of ortogonal polynoms and corresponding weights are calculated based on
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// iteration method (by bisection Newton algorithm). Constant values for initial
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// approximations were derived from the book:
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// M. Abramowitz, I. Stegun, Handbook of mathematical functions,
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// DOVER Publications INC, New York 1965 ; chapters 9, 10, and 22.
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// Author: V.Grichine, 18.04.1997
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// --------------------------------------------------------------------
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#ifndef G4VGAUSSIANQUADRATURE_HH
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#define G4VGAUSSIANQUADRATURE_HH 1
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#include "globals.hh"
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using function = G4double (*)(G4double);
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class G4VGaussianQuadrature
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{
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public:
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explicit G4VGaussianQuadrature(function pFunction);
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// Base constructor
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virtual ~G4VGaussianQuadrature();
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// Virtual destructor
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G4VGaussianQuadrature(const G4VGaussianQuadrature&) = delete;
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G4VGaussianQuadrature& operator=(const G4VGaussianQuadrature&) = delete;
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G4double GetAbscissa(G4int index) const;
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G4double GetWeight(G4int index) const;
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G4int GetNumber() const;
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// Access functions
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protected:
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G4double GammaLogarithm(G4double xx);
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// Auxiliary function which returns the value of std::log(gamma-function(x))
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// Data members common for GaussianQuadrature family
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//
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function fFunction; // pointer to the function to be integrated
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G4double* fAbscissa = nullptr; // array of abscissas
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G4double* fWeight = nullptr; // array of corresponding weights
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G4int fNumber = 0; // the number of points in fAbscissa and fWeight arrays
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};
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#endif
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