fix: kf+gsf: correct hole-tagging for edge case

Core/include/Acts/TrackFitting/KalmanFitter.hpp

@@ -590,6 +590,11 @@ class KalmanFitter {
     Result<void> filter(const Surface* surface, propagator_state_t& state,
                         const stepper_t& stepper, const navigator_t& navigator,
                         result_type& result) const {
+      const bool precedingMeasurementExists = result.measurementStates > 0;
+      const bool surfaceIsSensitive =
+          surface->associatedDetectorElement() != nullptr;
+      const bool surfaceHasMaterial = surface->surfaceMaterial() != nullptr;
+
       // Try to find the surface in the measurement surfaces
       auto sourceLinkIt = inputMeasurements->find(surface->geometryId());
       if (sourceLinkIt != inputMeasurements->end()) {
@@ -646,36 +651,33 @@ class KalmanFitter {
         // the lastTrackIndex.
         result.lastMeasurementIndex = result.lastTrackIndex;
 
-      } else if (surface->associatedDetectorElement() != nullptr ||
-                 surface->surfaceMaterial() != nullptr) {
+      } else if ((precedingMeasurementExists && surfaceIsSensitive) ||
+                 surfaceHasMaterial) {
         // We only create track states here if there is already measurement
         // detected or if the surface has material (no holes before the first
         // measurement)
-        if (result.measurementStates > 0 ||
-            surface->surfaceMaterial() != nullptr) {
-          auto trackStateProxyRes = detail::kalmanHandleNoMeasurement(
-              state, stepper, *surface, *result.fittedStates,
-              result.lastTrackIndex, true, logger(), freeToBoundCorrection);
-
-          if (!trackStateProxyRes.ok()) {
-            return trackStateProxyRes.error();
-          }
+        auto trackStateProxyRes = detail::kalmanHandleNoMeasurement(
+            state, stepper, *surface, *result.fittedStates,
+            result.lastTrackIndex, true, logger(), precedingMeasurementExists,
+            freeToBoundCorrection);
 
-          const auto& trackStateProxy = *trackStateProxyRes;
-          result.lastTrackIndex = trackStateProxy.index();
+        if (!trackStateProxyRes.ok()) {
+          return trackStateProxyRes.error();
+        }
 
-          if (trackStateProxy.typeFlags().test(TrackStateFlag::HoleFlag)) {
-            // Count the missed surface
-            result.missedActiveSurfaces.push_back(surface);
-          }
+        const auto& trackStateProxy = *trackStateProxyRes;
+        result.lastTrackIndex = trackStateProxy.index();
 
-          ++result.processedStates;
-        }
-        if (surface->surfaceMaterial() != nullptr) {
-          // Update state and stepper with material effects
-          materialInteractor(surface, state, stepper, navigator,
-                             MaterialUpdateStage::FullUpdate);
+        if (trackStateProxy.typeFlags().test(TrackStateFlag::HoleFlag)) {
+          // Count the missed surface
+          result.missedActiveSurfaces.push_back(surface);
         }
+
+        ++result.processedStates;
+
+        // Update state and stepper with (possible) material effects
+        materialInteractor(surface, state, stepper, navigator,
+                           MaterialUpdateStage::FullUpdate);
       }
       return Result<void>::success();
     }

Core/include/Acts/TrackFitting/detail/GsfActor.hpp

@@ -634,9 +634,11 @@ struct GsfActor {
                                    bool doCovTransport) const {
     const auto& surface = *navigator.currentSurface(state.navigation);
 
+    const bool precedingMeasurementExists = result.processedStates > 0;
+
     // Initialize as true, so that any component can flip it. However, all
     // components should behave the same
-    bool is_hole = true;
+    bool isHole = true;
 
     auto cmps = stepper.componentIterable(state.stepping);
     for (auto cmp : cmps) {
@@ -647,7 +649,8 @@ struct GsfActor {
       // now until we measure this is significant
       auto trackStateProxyRes = detail::kalmanHandleNoMeasurement(
           singleState, singleStepper, surface, tmpStates.traj,
-          MultiTrajectoryTraits::kInvalid, doCovTransport, logger());
+          MultiTrajectoryTraits::kInvalid, doCovTransport, logger(),
+          precedingMeasurementExists);
 
       if (!trackStateProxyRes.ok()) {
         return trackStateProxyRes.error();
@@ -656,15 +659,15 @@ struct GsfActor {
       const auto& trackStateProxy = *trackStateProxyRes;
 
       if (!trackStateProxy.typeFlags().test(TrackStateFlag::HoleFlag)) {
-        is_hole = false;
+        isHole = false;
       }
 
       tmpStates.tips.push_back(trackStateProxy.index());
       tmpStates.weights[tmpStates.tips.back()] = cmp.weight();
     }
 
     // These things should only be done once for all components
-    if (is_hole) {
+    if (isHole) {
       ++result.measurementHoles;
     }
 

Core/include/Acts/TrackFitting/detail/KalmanUpdateHelpers.hpp

@@ -135,7 +135,7 @@ template <typename propagator_state_t, typename stepper_t, typename traj_t>
 auto kalmanHandleNoMeasurement(
     propagator_state_t &state, const stepper_t &stepper, const Surface &surface,
     traj_t &fittedStates, const std::size_t lastTrackIndex, bool doCovTransport,
-    const Logger &logger,
+    const Logger &logger, const bool precedingMeasurementExists,
     const FreeToBoundCorrection &freeToBoundCorrection = FreeToBoundCorrection(
         false)) -> Result<typename traj_t::TrackStateProxy> {
   // Add a <mask> TrackState entry multi trajectory. This allocates storage for
@@ -172,16 +172,24 @@ auto kalmanHandleNoMeasurement(
   }
 
   // Set the track state flags
+  const bool surfaceHasMaterial = surface.surfaceMaterial() != nullptr;
+  const bool surfaceIsSensitive =
+      surface.associatedDetectorElement() != nullptr;
   auto typeFlags = trackStateProxy.typeFlags();
   typeFlags.set(TrackStateFlag::ParameterFlag);
-  if (surface.surfaceMaterial() != nullptr) {
+
+  if (surfaceHasMaterial) {
     typeFlags.set(TrackStateFlag::MaterialFlag);
   }
-  if (surface.associatedDetectorElement() != nullptr) {
+
+  if (surfaceIsSensitive && precedingMeasurementExists) {
     ACTS_VERBOSE("Detected hole on " << surface.geometryId());
     // If the surface is sensitive, set the hole type flag
     typeFlags.set(TrackStateFlag::HoleFlag);
-  } else if (surface.surfaceMaterial() != nullptr) {
+  } else if (surfaceIsSensitive) {
+    ACTS_VERBOSE("Skip hole (no preceding measurements) on surface "
+                 << surface.geometryId());
+  } else if (surfaceHasMaterial) {
     ACTS_VERBOSE("Detected in-sensitive surface " << surface.geometryId());
   }
 

Examples/Python/tests/root_file_hashes.txt

@@ -77,15 +77,15 @@ test_ML_Ambiguity_Solver__performance_ambiML.root: 284ff5c3a08c0b810938e4ac2f8ba
 test_refitting[odd]__trackstates_gsf_refit.root: 798a5b2e6d4b6d56e73ad107887f310c9463cc739ca1b69dad4a99d3419943ca
 test_refitting[odd]__tracksummary_gsf_refit.root: 16951808df6363d2acb99e385aec35ad723b634403ca0724a552ae9d3a2ae237
 test_refitting[generic]__trackstates_gsf_refit.root: b044574ab5dec9781ca2a1d72095f2393270766365a0e165904ff628191c284a
-test_refitting[generic]__tracksummary_gsf_refit.root: 6f8bd054c663197a5f5523e54ebc9695759b671eb14791f964073ed3c8a6f27f
-test_truth_tracking_kalman[generic-False-0.0]__trackstates_kf.root: 64a7f26c30f5a70e323dc5d43142a7cc81ad7ef04033095a1ae11d27c41333f0
-test_truth_tracking_kalman[generic-False-0.0]__tracksummary_kf.root: 6f8bd054c663197a5f5523e54ebc9695759b671eb14791f964073ed3c8a6f27f
+test_refitting[generic]__tracksummary_gsf_refit.root: 5b9ae5be9e82b2a1fd27d54fae5b9d8e89574f7a04a68cd491d4e3761c8fb834
+test_truth_tracking_kalman[generic-False-0.0]__trackstates_kf.root: 673a2b6a6fe855e8fcc3f0005a8d598ad61fd696177f54b2fa1af36517ac8f44
+test_truth_tracking_kalman[generic-False-0.0]__tracksummary_kf.root: 5b9ae5be9e82b2a1fd27d54fae5b9d8e89574f7a04a68cd491d4e3761c8fb834
 test_truth_tracking_kalman[generic-False-1000.0]__trackstates_kf.root: e69d1aacacecc3d7d6619605cdd179d9fb0e19734f7c35345284f9a0e01f36d1
-test_truth_tracking_kalman[generic-False-1000.0]__tracksummary_kf.root: 055a74d2747d360398cc846cc2791204491528896de78cca66b188e3ff530dc1
-test_truth_tracking_kalman[generic-True-0.0]__trackstates_kf.root: 64a7f26c30f5a70e323dc5d43142a7cc81ad7ef04033095a1ae11d27c41333f0
-test_truth_tracking_kalman[generic-True-0.0]__tracksummary_kf.root: 6f8bd054c663197a5f5523e54ebc9695759b671eb14791f964073ed3c8a6f27f
+test_truth_tracking_kalman[generic-False-1000.0]__tracksummary_kf.root: 8be4bcc0f05c90ffeb4ea7bbb517adee217550d59c2eed89a48ed3b4c5145c54
+test_truth_tracking_kalman[generic-True-0.0]__trackstates_kf.root: 673a2b6a6fe855e8fcc3f0005a8d598ad61fd696177f54b2fa1af36517ac8f44
+test_truth_tracking_kalman[generic-True-0.0]__tracksummary_kf.root: 5b9ae5be9e82b2a1fd27d54fae5b9d8e89574f7a04a68cd491d4e3761c8fb834
 test_truth_tracking_kalman[generic-True-1000.0]__trackstates_kf.root: e69d1aacacecc3d7d6619605cdd179d9fb0e19734f7c35345284f9a0e01f36d1
-test_truth_tracking_kalman[generic-True-1000.0]__tracksummary_kf.root: 055a74d2747d360398cc846cc2791204491528896de78cca66b188e3ff530dc1
+test_truth_tracking_kalman[generic-True-1000.0]__tracksummary_kf.root: 8be4bcc0f05c90ffeb4ea7bbb517adee217550d59c2eed89a48ed3b4c5145c54
 test_truth_tracking_kalman[odd-False-0.0]__trackstates_kf.root: 22c9f39a8e9569499205c024f7075d4125aca111c0e580c0320d6d93696062d5
 test_truth_tracking_kalman[odd-False-0.0]__tracksummary_kf.root: a6da8b8ca2cd0f09fcbae5d08885fa2aee39990f2f329ef659ef3c260141643a
 test_truth_tracking_kalman[odd-False-1000.0]__trackstates_kf.root: 214f3ded235a0da8d254e34f72253ee8d6dfa5b7f96040bccd760b51ee85a46f