/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

// ----------------------------------------------------------------------
// HEP coherent system of Units
//
// This file has been provided to CLHEP by Geant4 (simulation toolkit for HEP).
// Adapted to TGeo units base by Marko Petric
//
// The basic units are :
// millimeter              (millimeter)
// nanosecond              (nanosecond)
// Mega electron Volt      (MeV)
// positron charge         (eplus)
// degree Kelvin           (kelvin)
// the amount of substance (mole)
// luminous intensity      (candela)
// radian                  (radian)
// steradian               (steradian)
//
// Below is a non exhaustive list of derived and pratical units
// (i.e. mostly the SI units).
// You can add your own units.
//
// The SI numerical value of the positron charge is defined here,
// as it is needed for conversion factor : positron charge = e_SI (coulomb)
//
// The others physical constants are defined in the header file :
// PhysicalConstants.h
//
// Authors: M.Maire, S.Giani
//
// History:
//
// 06.02.96   Created.
// 28.03.96   Added miscellaneous constants.
// 05.12.97   E.Tcherniaev: Redefined pascal (to avoid warnings on WinNT)
// 20.05.98   names: meter, second, gram, radian, degree
//            (from Brian.Lasiuk@yale.edu (STAR)). Added luminous units.
// 05.08.98   angstrom, picobarn, microsecond, picosecond, petaelectronvolt
// 01.03.01   parsec
// 31.01.06   kilogray, milligray, microgray
// 29.04.08   use PDG 2006 value of e_SI
// 03.11.08   use PDG 2008 value of e_SI
// 19.08.15   added liter and its sub units (mma)
// 12.01.16   added symbols for microsecond (us) and picosecond (ps) (mma)
// 02.10.17   addopted units from CLHEP 2.3.4.3 and converted to TGeo unit base

#ifndef TGEANT4_SYSTEM_OF_UNITS_H
#define TGEANT4_SYSTEM_OF_UNITS_H

namespace TGeant4Unit {

//
// TGeo follows Geant3 convention as specified in manual
// "Unless otherwise specified, the following units are used throughout the program:
// centimeter, second, degree, GeV"

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

//
// Length [L]
//
static constexpr double millimeter = 1.0;
static constexpr double millimeter2 = millimeter * millimeter;
static constexpr double millimeter3 = millimeter * millimeter * millimeter;

static constexpr double centimeter = 10. * millimeter; // Base unit
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 degree = 1.0; // Base unit
static constexpr double radian = (180.0 / pi) * degree;
static constexpr double milliradian = 1.e-3 * 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 = 1.0;
static constexpr double second = 1.e+9 * nanosecond; // Base unit
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 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 = 1.602176487e-19; // positron charge in coulomb
static constexpr double coulomb = eplus / e_SI; // coulomb = 6.24150 e+18 * eplus

//
// Energy [E]
//
static constexpr double megaelectronvolt = 1.0;
static constexpr double electronvolt = 1.e-6 * megaelectronvolt;
static constexpr double kiloelectronvolt = 1.e-3 * megaelectronvolt;
static constexpr double gigaelectronvolt = 1.e+3 * megaelectronvolt; // Base unit
static constexpr double teraelectronvolt = 1.e+6 * megaelectronvolt;
static constexpr double petaelectronvolt = 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;
} // namespace TGeant4Unit

#endif /* TGEANT4_SYSTEM_OF_UNITS_H */