#include <cmath>

Macros
#define	_PI_ 3.1415926535897932384626433832795e0

#define	_PIHALF_ 1.57079632679489661923132169164e0

#define	_TWOPI_ 6.283185307179586476925286766559e0

#define	_SQRT6_ 2.4494897427831780981972840747059e0

#define	_SQRT_PI_ 1.77245385090551602729816748334e0

#define	_E_ 2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427427466391932003059921817413596629043572900334295260595630738132328627943490763233829880753195251019011573834187930702154089149934884167509244761460668082264800168477411853742345442437107539077744992069551702761838606261331384583000752044933826560297606737113200709328709127443747047230696977209310141692836819025515108657463772111252389784425056953696

Some conversion factors and fundamental constants needed by background module:
#define	_Mpc_over_m_ 3.085677581282e22

#define	_Gyr_over_Mpc_ 3.06601394e2

#define	_c_ 2.99792458e8

#define	_G_ 6.67428e-11

#define	_eV_ 1.602176487e-19

double	Omega0gFromTcmb (double T_cmb, double h)

double	TcmbFromOmega0g (double Omega0_g, double h)

Detailed Description

Physics constants and conversion factors used across CLASS.

Macro Definition Documentation

◆ _PI_

#define _PI_ 3.1415926535897932384626433832795e0

The number pi

◆ _PIHALF_

#define _PIHALF_ 1.57079632679489661923132169164e0

pi divided by 2

◆ _TWOPI_

#define _TWOPI_ 6.283185307179586476925286766559e0

2 times pi

◆ _SQRT6_

#define _SQRT6_ 2.4494897427831780981972840747059e0

square root of 6.

◆ _SQRT_PI_

#define _SQRT_PI_ 1.77245385090551602729816748334e0

square root of pi.

◆ _E_

#define _E_ 2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427427466391932003059921817413596629043572900334295260595630738132328627943490763233829880753195251019011573834187930702154089149934884167509244761460668082264800168477411853742345442437107539077744992069551702761838606261331384583000752044933826560297606737113200709328709127443747047230696977209310141692836819025515108657463772111252389784425056953696

exponential of one

◆ _Mpc_over_m_

#define _Mpc_over_m_ 3.085677581282e22

conversion factor from meters to megaparsecs

◆ _Gyr_over_Mpc_

#define _Gyr_over_Mpc_ 3.06601394e2

conversion factor from megaparsecs to gigayears (c=1 units, Julian years of 365.25 days)

◆ _c_

#define _c_ 2.99792458e8

c in m/s

◆ _G_

#define _G_ 6.67428e-11

Newton constant in m^3/Kg/s^2

◆ _eV_

#define _eV_ 1.602176487e-19

1 eV expressed in J

Function Documentation

◆ Omega0gFromTcmb()

double Omega0gFromTcmb	(	double	T_cmb,
		double	h
	)

inline

Photon density parameter from CMB temperature. Omega0_g = (4 sigma_B / c) T^4 / (3 c^2 1e10 h^2 / Mpc_over_m^2 / 8 pi G), with sigma_B = 2 pi^5 k_B^4 / (15 h_P^3 c^2). Single source of truth for the T_cmb <-> Omega0_g conversion. Free function (not a PhotonsSpecies method) so that background.h's default member initializer can call it without the photons.h <-> background.h include cycle.

◆ TcmbFromOmega0g()

double TcmbFromOmega0g	(	double	Omega0_g,
		double	h
	)