More sensible API

agasc/agasc.py

@@ -19,11 +19,6 @@
 
 MAG_CATID_SUPPLEMENT = 128
 
-# Number of stars above which get_stars() will read the entire AGASC and process
-# in memory instead of using tables.read_where. Around 5000 is the cross-over
-# in speed (empirically on a Mac with SSD drive).
-GET_STARS_METHOD_THRESHOLD = 5000
-
 
 def load_supplement():
     supplement = {}
@@ -355,7 +350,8 @@ def _get_rows_read_entire(ids_1d, dates_1d, agasc_file):
     return rows
 
 
-def get_stars(ids, agasc_file=None, dates=None, fix_color1=True, use_mag_est=False):
+def get_stars(ids, agasc_file=None, dates=None, read_entire_agasc=5000, fix_color1=True,
+              use_mag_est=False):
     """
     Get AGASC catalog entries for star ``ids`` at ``dates``.
 
@@ -367,9 +363,8 @@ def get_stars(ids, agasc_file=None, dates=None, fix_color1=True, use_mag_est=Fal
     the HDF5 ``tables.read_where()`` function to get one star at a time from the
     HDF5 file, or by reading the entire table into memory and doing the search
     by making a dict index by AGASC ID. Tests indicate that the latter is faster
-    for about 5000 or more stars, so this function will choose the method based
-    on the ``GET_STARS_METHOD_THRESHOLD`` module constant which is set at 5000.
-    If necessary you can change that module constant.
+    for about 5000 or more stars, so this function will read the entire AGASC if
+    the number of stars is greater than ``read_entire_agasc``.
 
     Unlike the similar ``get_star`` function, this adds a ``DATE`` column
     indicating the date at which the star coordinates (RA_PMCORR, DEC_PMCORR)
@@ -411,6 +406,7 @@ def get_stars(ids, agasc_file=None, dates=None, fix_color1=True, use_mag_est=Fal
     :param dates: Dates for proper motion (scalar or array) (default=Now)
     :param fix_color1: set COLOR1=COLOR2 * 0.85 for stars with V-I color (default=True)
     :param use_mag_est: Use estimated mag from AGASC supplement where available (default=False)
+    :param read_entire_agasc: Number of stars above which to read the entire AGASC (default=5000)
     :returns: astropy Table of AGASC entries, or Table Row of one entry for scalar input
     """
 
@@ -423,7 +419,7 @@ def get_stars(ids, agasc_file=None, dates=None, fix_color1=True, use_mag_est=Fal
     ids, dates = np.broadcast_arrays(ids, dates_in)
     ids_1d, dates_1d = np.atleast_1d(ids), np.atleast_1d(dates)
 
-    if len(ids_1d) < GET_STARS_METHOD_THRESHOLD:
+    if len(ids_1d) < read_entire_agasc:
         rows = _get_rows_read_where(ids_1d, dates_1d, agasc_file)
         method = 'tables_read_where'
     else:

agasc/tests/test_agasc_2.py

@@ -265,13 +265,7 @@ def test_get_stars_many():
     stars = agasc.get_agasc_cone(0, 0, radius=0.5)
     agasc_ids = stars['AGASC_ID']
     stars1 = agasc.get_stars(agasc_ids, dates='2020:001')  # read_where method
-
-    orig_threshold = agasc.GET_STARS_METHOD_THRESHOLD
-    try:
-        agasc.GET_STARS_METHOD_THRESHOLD = 1
-        stars2 = agasc.get_stars(agasc_ids, dates='2020:001')  # read entire AGASC
-    finally:
-        agasc.GET_STARS_METHOD_THRESHOLD = orig_threshold
+    stars2 = agasc.get_stars(agasc_ids, dates='2020:001', read_entire_agasc=1)  # read entire AGASC
 
     assert stars1.get_stars_method == 'tables_read_where'
     assert stars2.get_stars_method == 'read_entire_agasc'