| [833] | 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | //
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| 27 | // $Id: G4VGaussianQuadrature.cc,v 1.7 2006/06/29 19:00:23 gunter Exp $
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| [1337] | 28 | // GEANT4 tag $Name: geant4-09-04-beta-01 $
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| [833] | 29 | //
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| 30 | // Implementation file for G4VGaussianQuadrature virtual base class
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| 31 | //
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| 32 |
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| 33 | #include "G4ios.hh"
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| 34 | #include "globals.hh"
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| 35 | #include "G4VGaussianQuadrature.hh"
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| 36 |
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| 37 | G4VGaussianQuadrature::G4VGaussianQuadrature( function pFunction )
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| 38 | : fFunction(pFunction), fAbscissa(0), fWeight(0), fNumber(0)
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| 39 | {
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| 40 | }
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| 41 |
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| 42 | // -------------------------------------------------------------------
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| 43 | //
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| 44 | // Virtual destructor which deletes dynamically allocated memory
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| 45 | //
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| 46 |
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| 47 | G4VGaussianQuadrature::~G4VGaussianQuadrature()
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| 48 | {
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| 49 | delete[] fAbscissa ;
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| 50 | delete[] fWeight ;
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| 51 | }
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| 52 |
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| 53 | // -------------------------- Access functions ----------------------------------
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| 54 |
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| 55 | G4double
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| 56 | G4VGaussianQuadrature::GetAbscissa(G4int index) const
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| 57 | {
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| 58 | return fAbscissa[index] ;
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| 59 | }
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| 60 |
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| 61 | G4double
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| 62 | G4VGaussianQuadrature::GetWeight(G4int index) const
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| 63 | {
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| 64 | return fWeight[index] ;
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| 65 | }
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| 66 |
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| 67 | G4int G4VGaussianQuadrature::GetNumber() const
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| 68 | {
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| 69 | return fNumber ;
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| 70 | }
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| 71 |
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| 72 | // ----------------------------------------------------------------------------
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| 73 | //
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| 74 | // Auxiliary function which returns the value of std::log(gamma-function(x))
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| 75 | //
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| 76 |
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| 77 | G4double
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| 78 | G4VGaussianQuadrature::GammaLogarithm(G4double xx)
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| 79 | {
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| 80 |
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| 81 | // Returns the value ln(Gamma(xx) for xx > 0. Full accuracy is obtained for
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| 82 | // xx > 1. For 0 < xx < 1. the reflection formula (6.1.4) can be used first.
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| 83 | // (Adapted from Numerical Recipes in C)
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| 84 |
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| 85 | static G4double cof[6] = { 76.18009172947146, -86.50532032941677,
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| 86 | 24.01409824083091, -1.231739572450155,
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| 87 | 0.1208650973866179e-2, -0.5395239384953e-5 } ;
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| 88 | G4double x = xx - 1.0;
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| 89 | G4double tmp = x + 5.5;
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| 90 | tmp -= (x + 0.5) * std::log(tmp);
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| 91 | G4double ser = 1.000000000190015;
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| 92 |
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| 93 | for ( size_t j = 0; j <= 5; j++ )
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| 94 | {
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| 95 | x += 1.0;
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| 96 | ser += cof[j]/x;
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| 97 | }
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| 98 | return -tmp + std::log(2.5066282746310005*ser);
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| 99 | }
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