include/EvtGenModels/EvtBtoXsgammaFermiUtil.hh

0001
0002 /***********************************************************************
0003 * Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
0004 *                                                                      *
0005 * This file is part of EvtGen.                                         *
0006 *                                                                      *
0007 * EvtGen is free software: you can redistribute it and/or modify       *
0008 * it under the terms of the GNU General Public License as published by *
0009 * the Free Software Foundation, either version 3 of the License, or    *
0010 * (at your option) any later version.                                  *
0011 *                                                                      *
0012 * EvtGen is distributed in the hope that it will be useful,            *
0013 * but WITHOUT ANY WARRANTY; without even the implied warranty of       *
0014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
0015 * GNU General Public License for more details.                         *
0016 *                                                                      *
0017 * You should have received a copy of the GNU General Public License    *
0018 * along with EvtGen.  If not, see <https://www.gnu.org/licenses/>.     *
0019 ***********************************************************************/
0020
0021 #ifndef EVTBTOXSGAMMAFERMIUTIL_HH
0022 #define EVTBTOXSGAMMAFERMIUTIL_HH
0023
0024 #include <vector>
0025
0026 // Description:
0027 //       Class to hold various fermi functions and their helper functions. The
0028 //       fermi functions are used in EvtBtoXsgammaKagan.
0029
0030 class EvtBtoXsgammaFermiUtil final {
0031     //--------------------
0032     // Instance Members --
0033     //--------------------
0034
0035   public:
0036     //Exponential function
0037     static double FermiExpFunc( double var, const std::vector<double>& coeffs );
0038
0039     //Gaussian function and its helper functions
0040     static double FermiGaussFunc( double, std::vector<double> const& coeffs );
0041     static double FermiGaussFuncRoot( double, double, double,
0042                                       std::vector<double>& coeffs );
0043     static double FermiGaussRootFcnA( double, const std::vector<double>& coeffs1,
0044                                       const std::vector<double>& coeffs2 );
0045     static double FermiGaussRootFcnB( double, const std::vector<double>& coeffs1,
0046                                       const std::vector<double>& coeffs2 );
0047     static double Gamma( double, const std::vector<double>& coeffs );
0048
0049     //Roman function and its helper functions
0050     static double BesselI1( double );
0051     static double BesselK1( double );
0052     static double FermiRomanFuncRoot( double, double );
0053     static double FermiRomanRootFcnA( double );
0054     static double FermiRomanFunc( double, std::vector<double> const& coeffs );
0055 };
0056
0057 #endif