Merge pull request #146 from cta-observatory/auto_flatfield_heuristic

Determine default for use_flatfield_heuristic by date

ctapipe_io_lst/__init__.py

@@ -17,6 +17,7 @@
     OpticsDescription,
 )
 from enum import IntFlag, auto
+from astropy.time import Time
 
 from ctapipe.io import EventSource, read_table
 from ctapipe.io.datalevels import DataLevel
@@ -43,9 +44,14 @@
     HIGH_GAIN, N_GAINS, N_PIXELS, N_SAMPLES
 )
 
+
 __all__ = ['LSTEventSource', '__version__']
 
 
+# Date from which the flatfield heuristic will be switch off by default
+NO_FF_HEURISTIC_DATE = Time("2022-01-01T00:00:00")
+
+
 class TriggerBits(IntFlag):
     '''
     See TIB User manual
@@ -197,12 +203,14 @@ class LSTEventSource(EventSource):
     ).tag(config=True)
 
     use_flatfield_heuristic = Bool(
-        default_value=False,
+        default_value=None,
+        allow_none=True,
         help=(
-            'If true, try to identify flat field events independent of the'
-            ' trigger type in the event. This should only be needed for data'
-            ' from before 2022, when a TIB firmware update fixed the issue with'
-            ' unreliable UCTS information in the event data'
+            'Whether or not to try to identify flat field events independent of'
+            ' the trigger type in the event. If None (the default) the decision'
+            ' will be made based on the date of the run, as this should only be'
+            ' needed for data from before 2022, when a TIB firmware update fixed'
+            ' the issue with unreliable UCTS information in the event data'
         ),
     ).tag(config=True)
 
@@ -308,6 +316,11 @@ def __init__(self, input_url=None, **kwargs):
 
         self.read_pedestal_ids()
 
+        if self.use_flatfield_heuristic is None:
+            date_of_run = Time(self.camera_config.date, format='unix')
+            self.use_flatfield_heuristic = date_of_run < NO_FF_HEURISTIC_DATE
+            self.log.info(f"Changed `use_flatfield_heuristic` to {self.use_flatfield_heuristic}")
+
     @property
     def subarray(self):
         return self._subarray

ctapipe_io_lst/tests/test_stage1.py

@@ -27,7 +27,6 @@ def test_stage1(tmp_path):
 
     config = {
         'LSTEventSource': {
-            'use_flatfield_heuristic': True,
             'LSTR0Corrections': {
                 'drs4_pedestal_path': str(test_drs4_pedestal_path),
                 'drs4_time_calibration_path': str(test_time_calib_path),
@@ -71,6 +70,9 @@ def test_stage1(tmp_path):
     # test our custom default works
     assert tool.event_source.r0_r1_calibrator.gain_selector.threshold == 3500
 
+    # test it used the ff heuristic because run is from before 2022
+    assert tool.event_source.use_flatfield_heuristic
+
     parameters = read_table(output, '/dl1/event/telescope/parameters/tel_001')
     assert len(parameters) == 200