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24 // ******************************************* 24 // ********************************************************************
25 // 25 //
26 // G4VGaussianQuadrature class implementation 26 // G4VGaussianQuadrature class implementation
27 // 27 //
28 // Author: V.Grichine, 18.04.1997 28 // Author: V.Grichine, 18.04.1997
29 // ------------------------------------------- 29 // --------------------------------------------------------------------
30 30
31 #include "G4VGaussianQuadrature.hh" 31 #include "G4VGaussianQuadrature.hh"
32 #include "G4ios.hh" 32 #include "G4ios.hh"
33 #include "globals.hh" 33 #include "globals.hh"
34 34
35 G4VGaussianQuadrature::G4VGaussianQuadrature(f 35 G4VGaussianQuadrature::G4VGaussianQuadrature(function pFunction)
36 : fFunction(pFunction) 36 : fFunction(pFunction)
37 {} 37 {}
38 38
39 // ------------------------------------------- 39 // -------------------------------------------------------------------
40 // 40 //
41 // Virtual destructor which deletes dynamicall 41 // Virtual destructor which deletes dynamically allocated memory
42 // 42 //
43 43
44 G4VGaussianQuadrature::~G4VGaussianQuadrature( 44 G4VGaussianQuadrature::~G4VGaussianQuadrature()
45 { 45 {
46 delete[] fAbscissa; 46 delete[] fAbscissa;
47 delete[] fWeight; 47 delete[] fWeight;
48 } 48 }
49 49
50 // -------------------------- Access functions 50 // -------------------------- Access functions
51 // ---------------------------------- 51 // ----------------------------------
52 52
53 G4double G4VGaussianQuadrature::GetAbscissa(G4 53 G4double G4VGaussianQuadrature::GetAbscissa(G4int index) const
54 { 54 {
55 return fAbscissa[index]; 55 return fAbscissa[index];
56 } 56 }
57 57
58 G4double G4VGaussianQuadrature::GetWeight(G4in 58 G4double G4VGaussianQuadrature::GetWeight(G4int index) const
59 { 59 {
60 return fWeight[index]; 60 return fWeight[index];
61 } 61 }
62 62
63 G4int G4VGaussianQuadrature::GetNumber() const 63 G4int G4VGaussianQuadrature::GetNumber() const { return fNumber; }
64 64
65 // ------------------------------------------- 65 // ----------------------------------------------------------------------------
66 // 66 //
67 // Auxiliary function which returns the value 67 // Auxiliary function which returns the value of std::log(gamma-function(x))
68 // 68 //
69 69
70 G4double G4VGaussianQuadrature::GammaLogarithm 70 G4double G4VGaussianQuadrature::GammaLogarithm(G4double xx)
71 { 71 {
72 // Returns the value ln(Gamma(xx) for xx > 0 72 // Returns the value ln(Gamma(xx) for xx > 0. Full accuracy is obtained for
73 // xx > 1. For 0 < xx < 1. the reflection fo 73 // xx > 1. For 0 < xx < 1. the reflection formula (6.1.4) can be used first.
74 // (Adapted from Numerical Recipes in C) 74 // (Adapted from Numerical Recipes in C)
75 75
76 static const G4double cof[6] = { 76.18009172 76 static const G4double cof[6] = { 76.18009172947146, -86.50532032941677,
77 24.01409824 77 24.01409824083091, -1.231739572450155,
78 0.120865097 78 0.1208650973866179e-2, -0.5395239384953e-5 };
79 G4double x = xx - 1.0; 79 G4double x = xx - 1.0;
80 G4double tmp = x + 5.5; 80 G4double tmp = x + 5.5;
81 tmp -= (x + 0.5) * std::log(tmp); 81 tmp -= (x + 0.5) * std::log(tmp);
82 G4double ser = 1.000000000190015; 82 G4double ser = 1.000000000190015;
83 83
84 for(size_t j = 0; j <= 5; ++j) 84 for(size_t j = 0; j <= 5; ++j)
85 { 85 {
86 x += 1.0; 86 x += 1.0;
87 ser += cof[j] / x; 87 ser += cof[j] / x;
88 } 88 }
89 return -tmp + std::log(2.5066282746310005 * 89 return -tmp + std::log(2.5066282746310005 * ser);
90 } 90 }
91 91