docstrings for constants in enumerations.py (#499)

PyMPDATA/impl/enumerations.py

@@ -1,30 +1,40 @@
-""" common constants (mostly integer indices used for indexing tuples) """
+""" common constants named with the intention of improving code readibility
+(mostly integer indices used for indexing tuples) """
 
 import numpy as np
 
 ARG_FOCUS, ARG_DATA, ARG_DATA_OUTER, ARG_DATA_MID3D, ARG_DATA_INNER = 0, 1, 1, 2, 3
+""" indices within tuple passed in fill_halos boundary-condition calls """
 
 MAX_DIM_NUM = 3
+""" maximal number of dimensions supported by the package """
 
 OUTER, MID3D, INNER = 0, 1, -1
+""" labels for identifying 1st, 2nd, and 3rd dimensions """
 
-IMPL_META_AND_DATA = 0
-IMPL_BC = 1
+IMPL_META_AND_DATA, IMPL_BC = 0, 1
+""" indices of "meta and data" and "bc" elements of the impl tuple in Field instances """
 
-META_AND_DATA_META = 0
-META_AND_DATA_DATA = 1
+META_AND_DATA_META, META_AND_DATA_DATA = 0, 1
+""" indices of "meta" and "data" elements of the "meta and data" impl Field property """
 
 SIGN_LEFT, SIGN_RIGHT = +1, -1
+""" left-hand and right-hand domain sides as used in boundary conditions logic """
 
 RNG_START, RNG_STOP, RNG_STEP = 0, 1, 2
+""" indices of elements in range-expressing tuples """
 
 INVALID_INDEX = -44
+""" value with which never-to-be-used unused-dimension tuples are filled with in traversals """
 
-INVALID_INIT_VALUE = np.nan
-BUFFER_DEFAULT_VALUE = np.nan
+INVALID_INIT_VALUE, BUFFER_DEFAULT_VALUE = np.nan, np.nan
+""" values with which arrays are filled at initialisation """
 
 INVALID_HALO_VALUE = 666
+""" value used when constructing never-to-be-used instances of Constant boundary condition """
 
 INVALID_NULL_VALUE = 0.0
+""" value with which the never-to-be-used "null" fields are populated """
 
 ONE_FOR_STAGGERED_GRID = 1
+""" used for explaining the purpose of +1 index addition if related to Arakawa-C grid shift """