Merge pull request #2295 from cta-observatory/better_errors

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/reco/sklearn.py

@@ -18,6 +18,8 @@
 from tqdm import tqdm
 from traitlets import TraitError
 
+from ctapipe.exceptions import TooFewEvents
+
 from ..containers import (
     ArrayEventContainer,
     DispContainer,
@@ -847,7 +849,7 @@ def __init__(self, model_component, **kwargs):
 
     def __call__(self, telescope_type, table):
         if len(table) <= self.n_cross_validations:
-            raise ValueError(f"Too few events for {telescope_type}.")
+            raise TooFewEvents(f"Too few events for {telescope_type}.")
 
         self.log.info(
             "Starting cross-validation with %d folds for type %s.",

ctapipe/tools/tests/test_train.py

@@ -1,6 +1,7 @@
 import pytest
 
 from ctapipe.core import run_tool
+from ctapipe.exceptions import TooFewEvents
 from ctapipe.utils.datasets import resource_file
 
 
@@ -29,7 +30,7 @@ def test_too_few_events(tmp_path, dl2_shower_geometry_file):
     config = resource_file("train_energy_regressor.yaml")
     out_file = tmp_path / "energy.pkl"
 
-    with pytest.raises(ValueError, match="Too few events"):
+    with pytest.raises(TooFewEvents, match="No events after quality query"):
         run_tool(
             tool,
             argv=[

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 +114,18 @@ 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 +114,19 @@ 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 +165,19 @@ 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)
 

docs/changes/2295.maintenance.rst

@@ -0,0 +1,2 @@
+The tools to train ml models now provide better error messages in case
+the input files did not contain any events for specific telescope types.