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 // Class description: 00030 // 00031 // Class for realization of Gauss-Laguerre quadrature method 00032 // Roots of ortogonal polynoms and corresponding weights are calculated based on 00033 // iteration method (by bisection Newton algorithm). Constant values for initial 00034 // approximations were derived from the book: M. Abramowitz, I. Stegun, Handbook 00035 // of mathematical functions, DOVER Publications INC, New York 1965 ; chapters 9, 00036 // 10, and 22 . 00037 // 00038 // --------------------------------------------------------------------------- 00039 // 00040 // Constructor for Gauss-Laguerre quadrature method: integral from zero to 00041 // infinity of std::pow(x,alpha)*std::exp(-x)*f(x). The value of nLaguerre sets the accuracy. 00042 // The constructor creates arrays fAbscissa[0,..,nLaguerre-1] and 00043 // fWeight[0,..,nLaguerre-1] . The function GaussLaguerre(f) should be called 00044 // then with any f . 00045 // 00046 // G4GaussLaguerreQ( function pFunction, 00047 // G4double alpha, 00048 // G4int nLaguerre ) 00049 // 00050 // 00051 // ------------------------------------------------------------------------- 00052 // 00053 // Gauss-Laguerre method for integration of std::pow(x,alpha)*std::exp(-x)*pFunction(x) 00054 // from zero up to infinity. pFunction is evaluated in fNumber points for which 00055 // fAbscissa[i] and fWeight[i] arrays were created in constructor 00056 // 00057 // G4double Integral() const 00058 00059 // ------------------------------- HISTORY -------------------------------- 00060 // 00061 // 13.05.97 V.Grichine (Vladimir.Grichine@cern.chz0 00062 00063 #ifndef G4GAUSSLAGUERREQ_HH 00064 #define G4GAUSSLAGUERREQ_HH 00065 00066 #include "G4VGaussianQuadrature.hh" 00067 00068 class G4GaussLaguerreQ : public G4VGaussianQuadrature 00069 { 00070 public: 00071 G4GaussLaguerreQ( function pFunction, 00072 G4double alpha, 00073 G4int nLaguerre ) ; 00074 00075 // Methods 00076 00077 G4double Integral() const ; 00078 00079 private: 00080 00081 G4GaussLaguerreQ(const G4GaussLaguerreQ&); 00082 G4GaussLaguerreQ& operator=(const G4GaussLaguerreQ&); 00083 }; 00084 00085 #endif