Gabriele Cosmo
77 lines
3.0 KiB
C++
77 lines
3.0 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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//
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// $Id: G4GaussChebyshevQ.cc 67970 2013-03-13 10:10:06Z gcosmo $
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//
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#include "G4GaussChebyshevQ.hh"
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#include "G4PhysicalConstants.hh"
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// -----------------------------------------------------
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//
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// Constructor for Gauss-Chebyshev quadrature method
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G4GaussChebyshevQ::G4GaussChebyshevQ( function pFunction ,
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G4int nChebyshev )
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: G4VGaussianQuadrature(pFunction)
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{
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fNumber = nChebyshev ; // Try to reduce fNumber twice ??
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G4double cof = pi/fNumber ;
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fAbscissa = new G4double[fNumber] ;
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fWeight = new G4double[fNumber] ;
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for(G4int i=0;i<fNumber;i++)
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{
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fAbscissa[i] = std::cos(cof*(i + 0.5)) ;
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fWeight[i] = cof*std::sqrt(1 - fAbscissa[i]*fAbscissa[i]) ;
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}
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}
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// ----------------------------------------------------------------------
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//
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G4GaussChebyshevQ::~G4GaussChebyshevQ()
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{
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}
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// -------------------------------------------------------------------------------
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//
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// Integrates function pointed by fFunction from a to b by Gauss-Chebyshev
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// quadrature method
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G4double
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G4GaussChebyshevQ::Integral(G4double a, G4double b) const
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{
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G4double xDiff=0.5*(b - a),
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xMean=0.5*(a + b),
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dx=0.0, integral=0.0 ;
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for(G4int i=0;i<fNumber;i++)
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{
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dx = xDiff*fAbscissa[i] ;
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integral += fWeight[i]*fFunction(xMean + dx) ;
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}
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return integral *= xDiff ;
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}
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