refactor!: move SSS coordinate information to spacePointData (#2004)

This PR moves the calculation of `topStripVector` and `bottomStripVector` to `spacePointData`, so we can calculate these values only once per event, since these values are calculated for ~95% of the input space points anyway.

@CarloVarni

Core/include/Acts/EventData/SpacePointData.hpp

@@ -53,22 +53,14 @@ class SpacePointData {
   void clear();
 
   ///
-  bool hasDynamicVariable() const { return not m_topHalfStripLength.empty(); }
+  bool hasDynamicVariable() const { return not m_topStripVector.empty(); }
 
-  const float& getTopHalfStripLength(std::size_t idx) const {
-    return m_topHalfStripLength[idx];
+  const Acts::Vector3& getTopStripVector(std::size_t idx) const {
+    return m_topStripVector[idx];
   }
 
-  const float& getBottomHalfStripLength(std::size_t idx) const {
-    return m_bottomHalfStripLength[idx];
-  }
-
-  const Acts::Vector3& getTopStripDirection(std::size_t idx) const {
-    return m_topStripDirection[idx];
-  }
-
-  const Acts::Vector3& getBottomStripDirection(std::size_t idx) const {
-    return m_bottomStripDirection[idx];
+  const Acts::Vector3& getBottomStripVector(std::size_t idx) const {
+    return m_bottomStripVector[idx];
   }
 
   const Acts::Vector3& getStripCenterDistance(std::size_t idx) const {
@@ -79,20 +71,12 @@ class SpacePointData {
     return m_topStripCenterPosition[idx];
   }
 
-  void setTopHalfStripLength(std::size_t idx, const float& value) {
-    m_topHalfStripLength[idx] = value;
-  }
-
-  void setBottomHalfStripLength(std::size_t idx, const float& value) {
-    m_bottomHalfStripLength[idx] = value;
-  }
-
-  void setTopStripDirection(std::size_t idx, const Acts::Vector3& value) {
-    m_topStripDirection[idx] = value;
+  void setTopStripVector(std::size_t idx, const Acts::Vector3& value) {
+    m_topStripVector[idx] = value;
   }
 
-  void setBottomStripDirection(std::size_t idx, const Acts::Vector3& value) {
-    m_bottomStripDirection[idx] = value;
+  void setBottomStripVector(std::size_t idx, const Acts::Vector3& value) {
+    m_bottomStripVector[idx] = value;
   }
 
   void setStripCenterDistance(std::size_t idx, const Acts::Vector3& value) {
@@ -109,10 +93,8 @@ class SpacePointData {
   std::vector<float> m_deltaR{};
 
   /// dynamic variables
-  std::vector<float> m_topHalfStripLength{};
-  std::vector<float> m_bottomHalfStripLength{};
-  std::vector<Acts::Vector3> m_topStripDirection{};
-  std::vector<Acts::Vector3> m_bottomStripDirection{};
+  std::vector<Acts::Vector3> m_topStripVector{};
+  std::vector<Acts::Vector3> m_bottomStripVector{};
   std::vector<Acts::Vector3> m_stripCenterDistance{};
   std::vector<Acts::Vector3> m_topStripCenterPosition{};
 };
@@ -142,10 +124,8 @@ inline void SpacePointData::resize(std::size_t n, bool resizeDynamic) {
   m_deltaR.resize(n, 0.);
 
   if (resizeDynamic) {
-    m_topHalfStripLength.resize(n, 0.);
-    m_bottomHalfStripLength.resize(n, 0.);
-    m_topStripDirection.resize(n, {0, 0, 0});
-    m_bottomStripDirection.resize(n, {0, 0, 0});
+    m_topStripVector.resize(n, {0, 0, 0});
+    m_bottomStripVector.resize(n, {0, 0, 0});
     m_stripCenterDistance.resize(n, {0, 0, 0});
     m_topStripCenterPosition.resize(n, {0, 0, 0});
   }
@@ -156,10 +136,8 @@ inline void SpacePointData::clear() {
   m_quality.clear();
   m_deltaR.clear();
   // dynamicvariables
-  m_topHalfStripLength.clear();
-  m_bottomHalfStripLength.clear();
-  m_topStripDirection.clear();
-  m_bottomStripDirection.clear();
+  m_topStripVector.clear();
+  m_bottomStripVector.clear();
   m_stripCenterDistance.clear();
   m_topStripCenterPosition.clear();
 }

Core/include/Acts/Seeding/SeedFinderUtils.ipp

@@ -162,23 +162,19 @@ inline bool xyzCoordinateCheck(
 
   std::size_t index = sp.index();
 
-  const float& topHalfStripLength = spacePointData.getTopHalfStripLength(index);
-  const float& bottomHalfStripLength =
-      spacePointData.getBottomHalfStripLength(index);
-  const Acts::Vector3& topStripDirection =
-      spacePointData.getTopStripDirection(index);
-  const Acts::Vector3& bottomStripDirection =
-      spacePointData.getBottomStripDirection(index);
+  // prepare variables
+  const Acts::Vector3& topStripVector = spacePointData.getTopStripVector(index);
+  const Acts::Vector3& bottomStripVector =
+      spacePointData.getBottomStripVector(index);
   const Acts::Vector3& stripCenterDistance =
       spacePointData.getStripCenterDistance(index);
 
-  // prepare variables
-  double xTopStripVector = topHalfStripLength * topStripDirection[0];
-  double yTopStripVector = topHalfStripLength * topStripDirection[1];
-  double zTopStripVector = topHalfStripLength * topStripDirection[2];
-  double xBottomStripVector = bottomHalfStripLength * bottomStripDirection[0];
-  double yBottomStripVector = bottomHalfStripLength * bottomStripDirection[1];
-  double zBottomStripVector = bottomHalfStripLength * bottomStripDirection[2];
+  const double& xTopStripVector = topStripVector[0];
+  const double& yTopStripVector = topStripVector[1];
+  const double& zTopStripVector = topStripVector[2];
+  const double& xBottomStripVector = bottomStripVector[0];
+  const double& yBottomStripVector = bottomStripVector[1];
+  const double& zBottomStripVector = bottomStripVector[2];
 
   // cross product between top strip vector and spacepointPosition
   double d1[3] = {yTopStripVector * spacepointPosition[2] -

Examples/Algorithms/TrackFinding/src/SeedingAlgorithm.cpp

@@ -259,14 +259,20 @@ ActsExamples::ProcessCode ActsExamples::SeedingAlgorithm::execute(
       const auto& collection = spacePointsGrouping.grid().at(grid_glob_bin);
       for (const auto& sp : collection) {
         std::size_t index = sp->index();
-        state.spacePointData.setTopHalfStripLength(
-            index, m_cfg.seedFinderConfig.getTopHalfStripLength(sp->sp()));
-        state.spacePointData.setBottomHalfStripLength(
-            index, m_cfg.seedFinderConfig.getBottomHalfStripLength(sp->sp()));
-        state.spacePointData.setTopStripDirection(
-            index, m_cfg.seedFinderConfig.getTopStripDirection(sp->sp()));
-        state.spacePointData.setBottomStripDirection(
-            index, m_cfg.seedFinderConfig.getBottomStripDirection(sp->sp()));
+
+        const float topHalfStripLength =
+            m_cfg.seedFinderConfig.getTopHalfStripLength(sp->sp());
+        const float bottomHalfStripLength =
+            m_cfg.seedFinderConfig.getBottomHalfStripLength(sp->sp());
+        const Acts::Vector3 topStripDirection =
+            m_cfg.seedFinderConfig.getTopStripDirection(sp->sp());
+        const Acts::Vector3 bottomStripDirection =
+            m_cfg.seedFinderConfig.getBottomStripDirection(sp->sp());
+
+        state.spacePointData.setTopStripVector(
+            index, topHalfStripLength * topStripDirection);
+        state.spacePointData.setBottomStripVector(
+            index, bottomHalfStripLength * bottomStripDirection);
         state.spacePointData.setStripCenterDistance(
             index, m_cfg.seedFinderConfig.getStripCenterDistance(sp->sp()));
         state.spacePointData.setTopStripCenterPosition(