99 lines
3.4 KiB
C++
99 lines
3.4 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: G4VGaussianQuadrature.cc 69546 2013-05-08 09:50:34Z gcosmo $
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//
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// Implementation file for G4VGaussianQuadrature virtual base class
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//
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#include "G4ios.hh"
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#include "globals.hh"
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#include "G4VGaussianQuadrature.hh"
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G4VGaussianQuadrature::G4VGaussianQuadrature( function pFunction )
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: fFunction(pFunction), fAbscissa(0), fWeight(0), fNumber(0)
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{
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}
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// -------------------------------------------------------------------
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//
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// Virtual destructor which deletes dynamically allocated memory
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//
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G4VGaussianQuadrature::~G4VGaussianQuadrature()
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{
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delete[] fAbscissa ;
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delete[] fWeight ;
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}
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// -------------------------- Access functions ----------------------------------
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G4double
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G4VGaussianQuadrature::GetAbscissa(G4int index) const
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{
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return fAbscissa[index] ;
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}
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G4double
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G4VGaussianQuadrature::GetWeight(G4int index) const
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{
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return fWeight[index] ;
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}
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G4int G4VGaussianQuadrature::GetNumber() const
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{
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return fNumber ;
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}
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// ----------------------------------------------------------------------------
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//
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// Auxiliary function which returns the value of std::log(gamma-function(x))
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//
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G4double
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G4VGaussianQuadrature::GammaLogarithm(G4double xx)
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{
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// Returns the value ln(Gamma(xx) for xx > 0. Full accuracy is obtained for
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// xx > 1. For 0 < xx < 1. the reflection formula (6.1.4) can be used first.
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// (Adapted from Numerical Recipes in C)
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static const G4double cof[6] = { 76.18009172947146, -86.50532032941677,
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24.01409824083091, -1.231739572450155,
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0.1208650973866179e-2, -0.5395239384953e-5 };
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G4double x = xx - 1.0;
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G4double tmp = x + 5.5;
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tmp -= (x + 0.5) * std::log(tmp);
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G4double ser = 1.000000000190015;
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for ( size_t j = 0; j <= 5; j++ )
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{
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x += 1.0;
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ser += cof[j]/x;
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}
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return -tmp + std::log(2.5066282746310005*ser);
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}
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