00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // 00027 // $Id$ 00028 // 00029 // Implementation file for G4VGaussianQuadrature virtual base class 00030 // 00031 00032 #include "G4ios.hh" 00033 #include "globals.hh" 00034 #include "G4VGaussianQuadrature.hh" 00035 00036 G4VGaussianQuadrature::G4VGaussianQuadrature( function pFunction ) 00037 : fFunction(pFunction), fAbscissa(0), fWeight(0), fNumber(0) 00038 { 00039 } 00040 00041 // ------------------------------------------------------------------- 00042 // 00043 // Virtual destructor which deletes dynamically allocated memory 00044 // 00045 00046 G4VGaussianQuadrature::~G4VGaussianQuadrature() 00047 { 00048 delete[] fAbscissa ; 00049 delete[] fWeight ; 00050 } 00051 00052 // -------------------------- Access functions ---------------------------------- 00053 00054 G4double 00055 G4VGaussianQuadrature::GetAbscissa(G4int index) const 00056 { 00057 return fAbscissa[index] ; 00058 } 00059 00060 G4double 00061 G4VGaussianQuadrature::GetWeight(G4int index) const 00062 { 00063 return fWeight[index] ; 00064 } 00065 00066 G4int G4VGaussianQuadrature::GetNumber() const 00067 { 00068 return fNumber ; 00069 } 00070 00071 // ---------------------------------------------------------------------------- 00072 // 00073 // Auxiliary function which returns the value of std::log(gamma-function(x)) 00074 // 00075 00076 G4double 00077 G4VGaussianQuadrature::GammaLogarithm(G4double xx) 00078 { 00079 00080 // Returns the value ln(Gamma(xx) for xx > 0. Full accuracy is obtained for 00081 // xx > 1. For 0 < xx < 1. the reflection formula (6.1.4) can be used first. 00082 // (Adapted from Numerical Recipes in C) 00083 00084 static G4double cof[6] = { 76.18009172947146, -86.50532032941677, 00085 24.01409824083091, -1.231739572450155, 00086 0.1208650973866179e-2, -0.5395239384953e-5 } ; 00087 G4double x = xx - 1.0; 00088 G4double tmp = x + 5.5; 00089 tmp -= (x + 0.5) * std::log(tmp); 00090 G4double ser = 1.000000000190015; 00091 00092 for ( size_t j = 0; j <= 5; j++ ) 00093 { 00094 x += 1.0; 00095 ser += cof[j]/x; 00096 } 00097 return -tmp + std::log(2.5066282746310005*ser); 00098 }