////////////////////////////////////////////////////////////////////
/// \class RAT::FermiFunction
///
/// \brief Returns the shape of the beta spectrum
///
/// \author Joe Formaggio and Jason Detwiler -- not on SNO+
/// \author Logan Sibley <lsibley@ualberta.ca> -- contact person
///
/// REVISION HISTORY:\n
///    11 Jan 2006 : WGS \n
///    28 May 2010 : Logan Sibley - change to the way the screening correction
///                  is calculated. Also, the screening potential is now
///                  calculated at Z of mother. \n
///    28 Sep 2010 : Logan Sibley - include additional shaping correction
///                  calculation using the last three columns of beta_decays.dat
///
/// \details These constants and functions are copied from the original code
///         from Joe Formaggio and Jason Detwiler, even though they duplicate
///         some definitions that can be found in Geant4. As a precaution,
///         I've put them in the RAT namespace. If one were being complete,
///         one would revise constants like "ElectronMass" to be the Geant4
///         definitions. \n \n
///
///         The screening correction is not treated in a typical fashion, and
///         is by default turned off. See comments/citations in
///         FermiFunction.cc.
///
////////////////////////////////////////////////////////////////////

#ifndef __RAT_FermiFunction__
#define __RAT_FermiFunction__

#include <complex>

namespace RAT {

  static const double ElectronMass = 0.510998918;
  static const double AlphaMass    = 3727.42;
  static const double UnitMass = 931.502; // MeV

  double GetRandomNumber(double rmin = 0., double rmax = 1.);

  double Nucl_Beta(int Beta, double Z, double A, double W, double W0,
		   int N, double vMass, float Corr[], bool screen);

  double Nucl_Wave(int Beta, double Z, double A, double W, int k,
                   float Corr[], bool screen);

  double Coulomb_Corr(double Z, double W, double WPrime, int k, int Beta);

  double Nucl_Size(int Beta, double Z, double W, int k, float Corr[]);

  double Nucl_Radius(double A);

  double Nucl_Mass(double A, double Z);

  double Nucl_Wave_Phase(int Beta, double Z, double A, double W, int k,
			 int sel);

  double Screening_Potential(double Z, double p, int Beta);

  std::complex < double >Hyper1F1Norm(std::complex < double >A,
				      std::complex < double >B,
				      std::complex < double >Z);

  double Factorial(int N);

  double HyperGeometric_PQF(double A[], int nA, double B[], int nB,
			    double Z);

  double GammaLn(double xx);

  std::complex < double >GammaLn_Complex(std::complex < double >xx);

} // namespace RAT

#endif