EvtBtoXsgammaFermiUtil.hh

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#ifndef EVTBTOXSGAMMAFERMIUTIL_HH
#define EVTBTOXSGAMMAFERMIUTIL_HH

#include <vector>

// Description:
//       Class to hold various fermi functions and their helper functions. The
//       fermi functions are used in EvtBtoXsgammaKagan.

class EvtBtoXsgammaFermiUtil final {
    //--------------------
    // Instance Members --
    //--------------------

  public:
    //Exponential function
    static double FermiExpFunc( double var, const std::vector<double>& coeffs );

    //Gaussian function and its helper functions
    static double FermiGaussFunc( double, std::vector<double> const& coeffs );
    static double FermiGaussFuncRoot( double, double, double,
                                      std::vector<double>& coeffs );
    static double FermiGaussRootFcnA( double, const std::vector<double>& coeffs1,
                                      const std::vector<double>& coeffs2 );
    static double FermiGaussRootFcnB( double, const std::vector<double>& coeffs1,
                                      const std::vector<double>& coeffs2 );
    static double Gamma( double, const std::vector<double>& coeffs );

    //Roman function and its helper functions
    static double BesselI1( double );
    static double BesselK1( double );
    static double FermiRomanFuncRoot( double, double );
    static double FermiRomanRootFcnA( double );
    static double FermiRomanFunc( double, std::vector<double> const& coeffs );
};

#endif