fix: Wire optional seed result in TrackDensityVertexFinder after #2917

(#3002) In #2917 I changed the way how "no more seeds" is communicated in our vertexing code but forgot to wire this for the `TrackDensityVertexFinder` correctly.
acts-project · Mar 1, 2024 · abdddc6 · abdddc6
1 parent 3d96535
commit abdddc6
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Showing 4 changed files with 31 additions and 14 deletions.
diff --git a/CI/physmon/reference/performance_ivf_truth_estimated_hist.root b/CI/physmon/reference/performance_ivf_truth_estimated_hist.root
diff --git a/Core/include/Acts/Vertexing/GaussianTrackDensity.hpp b/Core/include/Acts/Vertexing/GaussianTrackDensity.hpp
@@ -117,7 +117,7 @@ class GaussianTrackDensity {
   /// InputTrack
   ///
   /// @return Pair of position of global maximum and Gaussian width
-  std::pair<double, double> globalMaximumWithWidth(
+  Result<std::optional<std::pair<double, double>>> globalMaximumWithWidth(
       State& state, const std::vector<InputTrack>& trackList) const;
 
   /// @brief Calculates the z position of the global maximum
@@ -128,8 +128,8 @@ class GaussianTrackDensity {
   /// InputTrack
   ///
   /// @return z position of the global maximum
-  double globalMaximum(State& state,
-                       const std::vector<InputTrack>& trackList) const;
+  Result<std::optional<double>> globalMaximum(
+      State& state, const std::vector<InputTrack>& trackList) const;
 
  private:
   /// The configuration

diff --git a/Core/src/Vertexing/GaussianTrackDensity.cpp b/Core/src/Vertexing/GaussianTrackDensity.cpp
@@ -14,11 +14,12 @@
 
 namespace Acts {
 
-std::pair<double, double> Acts::GaussianTrackDensity::globalMaximumWithWidth(
+Result<std::optional<std::pair<double, double>>>
+Acts::GaussianTrackDensity::globalMaximumWithWidth(
     State& state, const std::vector<InputTrack>& trackList) const {
   auto result = addTracks(state, trackList);
   if (!result.ok()) {
-    return std::make_pair(0., 0.);
+    return result.error();
   }
 
   double maxPosition = 0.;
@@ -58,15 +59,24 @@ std::pair<double, double> Acts::GaussianTrackDensity::globalMaximumWithWidth(
                       maxDensity, maxSecondDerivative);
   }
 
-  return (maxSecondDerivative == 0.)
-             ? std::make_pair(0., 0.)
-             : std::make_pair(maxPosition,
-                              std::sqrt(-(maxDensity / maxSecondDerivative)));
+  if (maxSecondDerivative == 0.) {
+    return std::nullopt;
+  }
+
+  return std::pair{maxPosition, std::sqrt(-(maxDensity / maxSecondDerivative))};
 }
 
-double Acts::GaussianTrackDensity::globalMaximum(
+Result<std::optional<double>> Acts::GaussianTrackDensity::globalMaximum(
     State& state, const std::vector<InputTrack>& trackList) const {
-  return globalMaximumWithWidth(state, trackList).first;
+  auto maxRes = globalMaximumWithWidth(state, trackList);
+  if (!maxRes.ok()) {
+    return maxRes.error();
+  }
+  const auto& maxOpt = *maxRes;
+  if (!maxOpt.has_value()) {
+    return std::nullopt;
+  }
+  return maxOpt->first;
 }
 
 Result<void> Acts::GaussianTrackDensity::addTracks(

diff --git a/Core/src/Vertexing/TrackDensityVertexFinder.cpp b/Core/src/Vertexing/TrackDensityVertexFinder.cpp
@@ -15,9 +15,16 @@ Acts::Result<std::vector<Acts::Vertex>> Acts::TrackDensityVertexFinder::find(
   GaussianTrackDensity::State densityState(trackVector.size());
 
   // Calculate z seed position
-  std::pair<double, double> zAndWidth =
-      m_cfg.trackDensityEstimator.globalMaximumWithWidth(densityState,
-                                                         trackVector);
+  auto zAndWidthRes = m_cfg.trackDensityEstimator.globalMaximumWithWidth(
+      densityState, trackVector);
+  if (!zAndWidthRes.ok()) {
+    return zAndWidthRes.error();
+  }
+  const auto& zAndWidthOpt = *zAndWidthRes;
+  if (!zAndWidthOpt) {
+    return std::vector<Vertex>();
+  }
+  const auto& zAndWidth = *zAndWidthOpt;
 
   double z = zAndWidth.first;