xMath.h

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/*
 * Thermal-FIST package
 * 
 * Copyright (c) 2014-2019 Volodymyr Vovchenko
 *
 * GNU General Public License (GPLv3 or later)
 */
#ifndef XMATH_H
#define XMATH_H

namespace thermalfist {

  namespace xMath {

    inline double Pi() { return 3.14159265358979323846; }

    inline double GeVtoifm() { return 5.06773; }

    inline double GeVtoifm2() { return GeVtoifm() * GeVtoifm(); }

    inline double GeVtoifm3() { return GeVtoifm() * GeVtoifm() * GeVtoifm(); }

    inline double mnucleon() { return 0.938; }

    inline double mpion() { return 0.138; }

    double BesselI(int n, double x);   
    double BesselK(int n, double x);   
    double BesselI0(double x);         
    double BesselK0(double x);         
    double BesselI1(double x);         
    double BesselK1(double x);         
    double BesselJ0(double x);         
    double BesselJ1(double x);         
    double BesselY0(double x);         
    double BesselY1(double x);         
    double StruveH0(double x);         
    double StruveH1(double x);         
    double StruveL0(double x);         
    double StruveL1(double x);         

    double BesselK0exp(double x);         // modified Bessel function K_0(x), divided by exponential factor
    double BesselK1exp(double x);         // modified Bessel function K_1(x), divided by exponential factor
    double BesselKexp(int n, double x);    // integer order modified Bessel function K_n(x), divided by exponential factor

    double BesselI0exp(double x);         // modified Bessel function I_0(x), divided by exponential factor
    double BesselI1exp(double x);         // modified Bessel function I_1(x), divided by exponential factor
    double BesselIexp(int n, double x);   // integer order modified Bessel function I_n(x), divided by exponential factor


    // Note that the functions Gamma and LogGamma are mutually dependent.
    double LogGamma(double);
    double Gamma(double);
  }

} // namespace thermalfist

#endif // XMATH_H