diff options
| -rw-r--r-- | fg21sim/utils/convert.py | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/fg21sim/utils/convert.py b/fg21sim/utils/convert.py index d238339..9eb9061 100644 --- a/fg21sim/utils/convert.py +++ b/fg21sim/utils/convert.py @@ -5,9 +5,9 @@ Utilities for conversion among common astronomical quantities. """ -import numpy as np import astropy.units as au -import numba + +from .units import (UnitConversions as AUC, Constants as AC) def Fnu_to_Tb(Fnu, omega, freq): @@ -67,15 +67,12 @@ def Sb_to_Tb(Sb, freq): return Fnu_to_Tb(Fnu, omega, freq) -@numba.jit(nopython=True) def Sb_to_Tb_fast(Sb, freq): """ Convert surface brightness to brightness temperature, using the Rayleigh-Jeans law, in the Rayleigh-Jeans limit. - This function does the calculations explicitly, and does NOT rely - on the `astropy.units`, therefore it is much faster. However, the - input parameters must be in right units. + Avoid using `astropy.units` to optimize the speed. Tb = Sb * c^2 / (2 * k_B * nu^2) @@ -100,22 +97,19 @@ def Sb_to_Tb_fast(Sb, freq): Unit: [K] """ # NOTE: [rad] & [sr] are dimensionless - arcsec2 = (np.deg2rad(1) / 3600) ** 2 # [sr] - c = 29979245800.0 # speed of light, [cm/s] - k_B = 1.3806488e-16 # Boltzmann constant, [erg/K] - coef = 1e-35 # take care the unit conversions - Tb = coef * (Sb * c*c) / (2 * k_B * freq*freq * arcsec2) # [K] + arcsec2 = AUC.arcsec2rad ** 2 # [sr] + Sb /= arcsec2 # [Jy/arcsec^2] -> [Jy/sr] + coef = 1e-35 # unit conversion coefficient + Tb = coef * (Sb * AC.c**2) / (2*AC.k_B * freq**2) # [K] return Tb -@numba.jit(nopython=True) def Fnu_to_Tb_fast(Fnu, omega, freq): """ Convert flux density to brightness temperature, using the Rayleigh-Jeans law, in the Rayleigh-Jeans limit. - This function does NOT invoke the `astropy.units`, therefore it is - much faster. + Avoid using `astropy.units` to optimize the speed. Parameters ---------- |