units: switch to simple module constants

pahfit/features/features.py

@@ -25,7 +25,7 @@
 from importlib import resources
 from pahfit.errors import PAHFITFeatureError
 from pahfit.features.features_format import BoundedMaskedColumn, BoundedParTableFormatter
-from pahfit.units import UNITS
+import pahfit.units
 
 # Feature kinds and associated parameters
 KIND_PARAMS = {'starlight': {'temperature', 'tau'},
@@ -36,9 +36,9 @@
                'absorption': {'wavelength', 'fwhm', 'tau', 'geometry'}}
 
 # Parameter default units: flux density/intensity/power (other units determined on fit)
-PARAM_UNITS = {'temperature': UNITS.temperature.value,
-               'wavelength': UNITS.wavelength.value,
-               'fwhm': UNITS.wavelength.value}
+PARAM_UNITS = {'temperature': pahfit.units.temperature,
+               'wavelength': pahfit.units.wavelength,
+               'fwhm': pahfit.units.wavelength}
 
 
 class UniqueKeyLoader(yaml.SafeLoader):

pahfit/units.py

@@ -1,18 +1,16 @@
-from enum import Enum
 import astropy.units as u
 from astropy.units import CompositeUnit
 
 
 # Working/default unitParameter default units: flux density/intensity/power
 # These are PAHFITs default science packs parameter and output units
-class UNITS(Enum):
-    temperature = u.K
-    wavelength = u.um
-    flux_density = u.mJy
-    flux_power = CompositeUnit(1e-22, (u.W, u.m), (1, -2))
-    solid_angle = u.sr
-    intensity = u.MJy / u.sr
-    intensity_power = CompositeUnit(1e-10, (u.W, u.m, u.sr), (1, -2, -1))
+temperature = u.K
+wavelength = u.um
+flux_density = u.mJy
+flux_power = CompositeUnit(1e-22, (u.W, u.m), (1, -2))
+solid_angle = u.sr
+intensity = u.MJy / u.sr
+intensity_power = CompositeUnit(1e-10, (u.W, u.m, u.sr), (1, -2, -1))
 
 # Note: integrated power units of 1e-22 W/m^2 (from flux) corresponds
 # to the unit 1e-10 W/m^2/sr (from intensity) if it occurs uniformly