fix the weight calculation in raw to sim hits association

.github/workflows/linux-eic-shell.yml

@@ -220,7 +220,7 @@ jobs:
     - name: Check for pragma once in changed files
       if: ${{ github.event_name == 'pull_request' }}
       run: |
-        missing_pragma_headers=$(git diff --name-only ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }} | grep "\.h$" | xargs -n 1 grep -L 'pragma once')
+        missing_pragma_headers=$(git diff --name-only ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }} | grep "\.h$" | xargs -n 1 -r grep -L 'pragma once')
         test -z "${missing_pragma_headers}"
     - name: Check for pragma once in all files
       if: ${{ github.event_name == 'push' || github.event_name == 'schedule' }}

src/algorithms/digi/SiliconTrackerDigi.cc

@@ -65,11 +65,14 @@ void SiliconTrackerDigi::process(const SiliconTrackerDigi::Input& input,
       debug("  edep is below threshold of {:.2f} [keV]", m_cfg.threshold / dd4hep::keV);
       continue;
     }
-
+    // the charge in RawTrackerHit is defined as int32_t to mimic ADC value.
+    // because our energy threshold is often sub-keV, it's better to save charge as eV.
+    // allowed range of int32_t would be eV to ~2GeV which should be sufficient.
+    int32_t sim_hit_charge = sim_hit.getEDep() * dd4hep::GeV / dd4hep::eV;
     if (!cell_hit_map.contains(sim_hit.getCellID())) {
       // This cell doesn't have hits
       cell_hit_map[sim_hit.getCellID()] = {
-          sim_hit.getCellID(), (std::int32_t)std::llround(sim_hit.getEDep() * 1e6),
+          sim_hit.getCellID(), sim_hit_charge,
           hit_time_stamp // ns->ps
       };
     } else {
@@ -83,18 +86,22 @@ void SiliconTrackerDigi::process(const SiliconTrackerDigi::Input& input,
 
       // sum deposited energy
       auto charge = hit.getCharge();
-      hit.setCharge(charge + (std::int32_t)std::llround(sim_hit.getEDep() * 1e6));
+      hit.setCharge(charge + sim_hit_charge);
     }
   }
 
   for (auto item : cell_hit_map) {
-    raw_hits->push_back(item.second);
-
+    auto raw_hit = item.second;
+    raw_hits->push_back(raw_hit);
     for (const auto& sim_hit : *sim_hits) {
       if (item.first == sim_hit.getCellID()) {
         // set association
         auto hitassoc = associations->create();
-        hitassoc.setWeight(1.0);
+        double weight = 0.0;
+        if (raw_hit.getCharge() > 0) {
+          weight = sim_hit.getEDep() * dd4hep::GeV / dd4hep::eV / raw_hit.getCharge();
+        }
+        hitassoc.setWeight(weight);
         hitassoc.setRawHit(item.second);
         hitassoc.setSimHit(sim_hit);
       }

src/algorithms/tracking/TrackerHitReconstruction.cc

@@ -68,8 +68,9 @@ void TrackerHitReconstruction::process(const Input& input, const Output& output)
                            std::size(dim) > 2 ? get_variance(dim[2] / mm) : 0.},
         static_cast<float>((double)(raw_hit.getTimeStamp()) / 1000.0), // ns
         m_cfg.timeResolution,                                          // in ns
-        static_cast<float>(raw_hit.getCharge() / 1.0e6),               // Collected energy (GeV)
-        0.0F);                                                         // Error on the energy
+        static_cast<float>(raw_hit.getCharge() * dd4hep::eV /
+                           dd4hep::GeV), // Collected energy (GeV)
+        0.0F);                           // Error on the energy
     rec_hit.setRawHit(raw_hit);
   }
 }