Better errors in case of no events in train tools

ctapipe/exceptions.py

@@ -0,0 +1,6 @@
+class CTAPipeException(Exception):
+    pass
+
+
+class TooFewEvents(CTAPipeException):
+    """Raised if something that needs a minimum number of event gets fewer"""

ctapipe/tools/train_disp_reconstructor.py

@@ -3,6 +3,7 @@
 
 from ctapipe.core import Tool
 from ctapipe.core.traits import Bool, Int, IntTelescopeParameter, Path
+from ctapipe.exceptions import TooFewEvents
 from ctapipe.io import TableLoader
 from ctapipe.reco import CrossValidator, DispReconstructor
 from ctapipe.reco.preprocessing import check_valid_rows, horizontal_to_telescope
@@ -113,10 +114,14 @@ def start(self):
     def _read_table(self, telescope_type):
         table = self.loader.read_telescope_events([telescope_type])
         self.log.info("Events read from input: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"Input file does not contain any events for telescope type {telescope_type}")
 
         mask = self.models.quality_query.get_table_mask(table)
         table = table[mask]
         self.log.info("Events after applying quality query: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"No events after quality query for telescope type {telescope_type}")
 
         table = self.models.feature_generator(table)
 

ctapipe/tools/train_energy_regressor.py

@@ -5,6 +5,7 @@
 
 from ctapipe.core import Tool
 from ctapipe.core.traits import Int, IntTelescopeParameter, Path
+from ctapipe.exceptions import TooFewEvents
 from ctapipe.io import TableLoader
 from ctapipe.reco import CrossValidator, EnergyRegressor
 from ctapipe.reco.preprocessing import check_valid_rows
@@ -113,11 +114,15 @@ def start(self):
 
     def _read_table(self, telescope_type):
         table = self.loader.read_telescope_events([telescope_type])
-
         self.log.info("Events read from input: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"Input file does not contain any events for telescope type {telescope_type}")
+
         mask = self.regressor.quality_query.get_table_mask(table)
         table = table[mask]
         self.log.info("Events after applying quality query: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"No events after quality query for telescope type {telescope_type}")
 
         table = self.regressor.feature_generator(table)
 

ctapipe/tools/train_particle_classifier.py

@@ -6,6 +6,7 @@
 
 from ctapipe.core.tool import Tool
 from ctapipe.core.traits import Int, IntTelescopeParameter, Path
+from ctapipe.exceptions import TooFewEvents
 from ctapipe.io import TableLoader
 from ctapipe.reco import CrossValidator, ParticleClassifier
 from ctapipe.reco.preprocessing import check_valid_rows
@@ -164,11 +165,15 @@ def start(self):
 
     def _read_table(self, telescope_type, loader, n_events=None):
         table = loader.read_telescope_events([telescope_type])
-
         self.log.info("Events read from input: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"Input file does not contain any events for telescope type {telescope_type}")
+
         mask = self.classifier.quality_query.get_table_mask(table)
         table = table[mask]
         self.log.info("Events after applying quality query: %d", len(table))
+        if len(table) == 0:
+            raise TooFewEvents(f"No events after quality query for telescope type {telescope_type}")
 
         table = self.classifier.feature_generator(table)