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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28 | // GEANT4 tag $Name: geant4-09-04-beta-01 $ |
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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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