#ifndef CLHEP_defs_h
#define CLHEP_defs_h

namespace CLHEP {


// UNITS //
//
//
//
static constexpr double     pi  = 3.14159265358979323846;
static constexpr double  twopi  = 2*pi;
static constexpr double halfpi  = pi/2;
static constexpr double     pi2 = pi*pi;

//
//
//
static constexpr double millimeter  = 1.;                        
static constexpr double millimeter2 = millimeter*millimeter;
static constexpr double millimeter3 = millimeter*millimeter*millimeter;

static constexpr double centimeter  = 10.*millimeter;   
static constexpr double centimeter2 = centimeter*centimeter;
static constexpr double centimeter3 = centimeter*centimeter*centimeter;

static constexpr double meter  = 1000.*millimeter;                  
static constexpr double meter2 = meter*meter;
static constexpr double meter3 = meter*meter*meter;

static constexpr double kilometer = 1000.*meter;                   
static constexpr double kilometer2 = kilometer*kilometer;
static constexpr double kilometer3 = kilometer*kilometer*kilometer;

static constexpr double parsec = 3.0856775807e+16*meter;

static constexpr double micrometer = 1.e-6 *meter;             
static constexpr double  nanometer = 1.e-9 *meter;
static constexpr double  angstrom  = 1.e-10*meter;
static constexpr double  fermi     = 1.e-15*meter;

static constexpr double      barn = 1.e-28*meter2;
static constexpr double millibarn = 1.e-3 *barn;
static constexpr double microbarn = 1.e-6 *barn;
static constexpr double  nanobarn = 1.e-9 *barn;
static constexpr double  picobarn = 1.e-12*barn;

// symbols
static constexpr double nm  = nanometer;                        
static constexpr double um  = micrometer;                        

static constexpr double mm  = millimeter;                        
static constexpr double mm2 = millimeter2;
static constexpr double mm3 = millimeter3;

static constexpr double cm  = centimeter;   
static constexpr double cm2 = centimeter2;
static constexpr double cm3 = centimeter3;

static constexpr double liter = 1.e+3*cm3;
static constexpr double  L = liter;
static constexpr double dL = 1.e-1*liter;
static constexpr double cL = 1.e-2*liter;
static constexpr double mL = 1.e-3*liter;       

static constexpr double m  = meter;                  
static constexpr double m2 = meter2;
static constexpr double m3 = meter3;

static constexpr double km  = kilometer;                   
static constexpr double km2 = kilometer2;
static constexpr double km3 = kilometer3;

static constexpr double pc = parsec;

//
// Angle
//
static constexpr double radian      = 1.;                  
static constexpr double milliradian = 1.e-3*radian;
static constexpr double degree = (pi/180.0)*radian;

static constexpr double   steradian = 1.;
  
// symbols
static constexpr double rad  = radian;
static constexpr double mrad = milliradian;
static constexpr double sr   = steradian;
static constexpr double deg  = degree;

//
// Time [T]
//
static constexpr double nanosecond  = 1.;
static constexpr double second      = 1.e+9 *nanosecond;
static constexpr double millisecond = 1.e-3 *second;
static constexpr double microsecond = 1.e-6 *second;
static constexpr double  picosecond = 1.e-12*second;

static constexpr double minute = 60*second;
static constexpr double hour   = 60*minute;
static constexpr double day    = 24*hour;
static constexpr double year   = 365*day;  

static constexpr double hertz = 1./second;
static constexpr double kilohertz = 1.e+3*hertz;
static constexpr double megahertz = 1.e+6*hertz;

// symbols
static constexpr double ns = nanosecond;
static constexpr double  s = second;
static constexpr double ms = millisecond;
static constexpr double us = microsecond;
static constexpr double ps = picosecond;

//
// Electric charge [Q]
//
static constexpr double eplus = 1. ;// positron charge
static constexpr double e_SI  = 1.602176634e-19;// positron charge in coulomb
static constexpr double coulomb = eplus/e_SI;// coulomb = 6.24150 e+18 * eplus

//
// Energy [E]
//
static constexpr double megaelectronvolt = 1. ;
static constexpr double     electronvolt = 1.e-6*megaelectronvolt;
static constexpr double kiloelectronvolt = 1.e-3*megaelectronvolt;
static constexpr double gigaelectronvolt = 1.e+3*megaelectronvolt;
static constexpr double teraelectronvolt = 1.e+6*megaelectronvolt;
static constexpr double petaelectronvolt = 1.e+9*megaelectronvolt;
static constexpr double millielectronvolt = 1.e-9*megaelectronvolt;  

static constexpr double joule = electronvolt/e_SI;// joule = 6.24150 e+12 * MeV

// symbols
static constexpr double MeV = megaelectronvolt;
static constexpr double  eV = electronvolt;
static constexpr double keV = kiloelectronvolt;
static constexpr double GeV = gigaelectronvolt;
static constexpr double TeV = teraelectronvolt;
static constexpr double PeV = petaelectronvolt;

//
// Mass [E][T^2][L^-2]
//
static constexpr double  kilogram = joule*second*second/(meter*meter);   
static constexpr double      gram = 1.e-3*kilogram;
static constexpr double milligram = 1.e-3*gram;

// symbols
static constexpr double  kg = kilogram;
static constexpr double   g = gram;
static constexpr double  mg = milligram;

//
// Power [E][T^-1]
//
static constexpr double watt = joule/second;// watt = 6.24150 e+3 * MeV/ns

//
// Force [E][L^-1]
//
static constexpr double newton = joule/meter;// newton = 6.24150 e+9 * MeV/mm

//
// Pressure [E][L^-3]
//
#define pascal hep_pascal                          // a trick to avoid warnings 
static constexpr double hep_pascal = newton/m2;   // pascal = 6.24150 e+3 * MeV/mm3
static constexpr double bar        = 100000*pascal; // bar    = 6.24150 e+8 * MeV/mm3
static constexpr double atmosphere = 101325*pascal; // atm    = 6.32420 e+8 * MeV/mm3

//
// Electric current [Q][T^-1]
//
static constexpr double      ampere = coulomb/second; // ampere = 6.24150 e+9 * eplus/ns
static constexpr double milliampere = 1.e-3*ampere;
static constexpr double microampere = 1.e-6*ampere;
static constexpr double  nanoampere = 1.e-9*ampere;

//
// Electric potential [E][Q^-1]
//
static constexpr double megavolt = megaelectronvolt/eplus;
static constexpr double kilovolt = 1.e-3*megavolt;
static constexpr double     volt = 1.e-6*megavolt;

//
// Electric resistance [E][T][Q^-2]
//
static constexpr double ohm = volt/ampere;// ohm = 1.60217e-16*(MeV/eplus)/(eplus/ns)

//
// Electric capacitance [Q^2][E^-1]
//
static constexpr double farad = coulomb/volt;// farad = 6.24150e+24 * eplus/Megavolt
static constexpr double millifarad = 1.e-3*farad;
static constexpr double microfarad = 1.e-6*farad;
static constexpr double  nanofarad = 1.e-9*farad;
static constexpr double  picofarad = 1.e-12*farad;

//
// Magnetic Flux [T][E][Q^-1]
//
static constexpr double weber = volt*second;// weber = 1000*megavolt*ns

//
// Magnetic Field [T][E][Q^-1][L^-2]
//
static constexpr double tesla     = volt*second/meter2;// tesla =0.001*megavolt*ns/mm2

static constexpr double gauss     = 1.e-4*tesla;
static constexpr double kilogauss = 1.e-1*tesla;

//
// Inductance [T^2][E][Q^-2]
//
static constexpr double henry = weber/ampere;// henry = 1.60217e-7*MeV*(ns/eplus)**2

//
// Temperature
//
static constexpr double kelvin = 1.;

//
// Amount of substance
//
static constexpr double mole = 1.;

//
// Activity [T^-1]
//
static constexpr double becquerel = 1./second ;
static constexpr double curie = 3.7e+10 * becquerel;
static constexpr double kilobecquerel = 1.e+3*becquerel;
static constexpr double megabecquerel = 1.e+6*becquerel;
static constexpr double gigabecquerel = 1.e+9*becquerel;
static constexpr double millicurie = 1.e-3*curie;
static constexpr double microcurie = 1.e-6*curie;
static constexpr double Bq = becquerel;
static constexpr double kBq = kilobecquerel;
static constexpr double MBq = megabecquerel;
static constexpr double GBq = gigabecquerel;
static constexpr double Ci = curie;
static constexpr double mCi = millicurie;
static constexpr double uCi = microcurie;

//
// Absorbed dose [L^2][T^-2]
//
static constexpr double      gray = joule/kilogram ;
static constexpr double  kilogray = 1.e+3*gray;
static constexpr double milligray = 1.e-3*gray;
static constexpr double microgray = 1.e-6*gray;

//
// Luminous intensity [I]
//
static constexpr double candela = 1.;

//
// Luminous flux [I]
//
static constexpr double lumen = candela*steradian;

//
// Illuminance [I][L^-2]
//
static constexpr double lux = lumen/meter2;

//
// Miscellaneous
//
static constexpr double perCent     = 0.01 ;
static constexpr double perThousand = 0.001;
static constexpr double perMillion  = 0.000001;



// CONSTANTS //

//
// 
//
static constexpr double Avogadro = 6.02214076e+23/mole;

//
// c   = 299.792458 mm/ns
// c^2 = 898.7404 (mm/ns)^2 
//
static constexpr double c_light   = 2.99792458e+8 * m/s;
static constexpr double c_squared = c_light * c_light;

//
// h     = 4.13566e-12 MeV*ns
// hbar  = 6.58212e-13 MeV*ns
// hbarc = 197.32705e-12 MeV*mm
//
static constexpr double h_Planck      = 6.62607015e-34 * joule*s;
static constexpr double hbar_Planck   = h_Planck/twopi;
static constexpr double hbarc         = hbar_Planck * c_light;
static constexpr double hbarc_squared = hbarc * hbarc;

//
//
//
static constexpr double electron_charge = - eplus; // see SystemOfUnits.h
static constexpr double e_squared = eplus * eplus;

//
// amu_c2 - atomic equivalent mass unit
//        - AKA, unified atomic mass unit (u)
// amu    - atomic mass unit
//
static constexpr double electron_mass_c2 = 0.510998910 * MeV;
static constexpr double   proton_mass_c2 = 938.272013 * MeV;
static constexpr double  neutron_mass_c2 = 939.56536 * MeV;
static constexpr double           amu_c2 = 931.494028 * MeV;
static constexpr double              amu = amu_c2/c_squared;

//
// permeability of free space mu0    = 2.01334e-16 Mev*(ns*eplus)^2/mm
// permittivity of free space epsil0 = 5.52636e+10 eplus^2/(MeV*mm)
//
static constexpr double mu0      = 4*pi*1.e-7 * henry/m;
static constexpr double epsilon0 = 1./(c_squared*mu0);

//
// electromagnetic coupling = 1.43996e-12 MeV*mm/(eplus^2)
//
static constexpr double elm_coupling           = e_squared/(4*pi*epsilon0);
static constexpr double fine_structure_const   = elm_coupling/hbarc;
static constexpr double classic_electr_radius  = elm_coupling/electron_mass_c2;
static constexpr double electron_Compton_length = hbarc/electron_mass_c2;
static constexpr double Bohr_radius = electron_Compton_length/fine_structure_const;

static constexpr double alpha_rcl2 = fine_structure_const
                                   *classic_electr_radius
                                   *classic_electr_radius;

static constexpr double twopi_mc2_rcl2 = twopi*electron_mass_c2
                                             *classic_electr_radius
                                             *classic_electr_radius;

static constexpr double Bohr_magneton = (eplus*hbarc*c_light)/(2*electron_mass_c2);
static constexpr double nuclear_magneton = (eplus*hbarc*c_light)/(2*proton_mass_c2);

//
//
//
static constexpr double k_Boltzmann = 8.617333e-11 * MeV/kelvin;

//
//
//
static constexpr double STP_Temperature = 273.15*kelvin;
static constexpr double STP_Pressure    = 1.*atmosphere;
static constexpr double kGasThreshold   = 10.*mg/cm3;

//
//
//
static constexpr double universe_mean_density = 1.e-25*g/cm3;

}  // namespace CLHEP

#endif