refactor!: move useBeamSpotConstraint to vertexingOptions (#2272)

Previously, the boolean member variable `useBeamSpotConstraint` of the
AMVF and IVF was set independently of the actual beam spot constraint
which was part of the `vertexingOptions`. This PR moves
`useBeamSpotConstraint` to `vertexingOptions` as well.

CI/physmon/fpe_masks.yml

@@ -10,5 +10,7 @@
   FLTUND: 1
 "Core/src/Utilities/AnnealingUtility.cpp:40":
   FLTUND: 1
-"Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp:119":
+"Core/src/Utilities/AnnealingUtility.cpp:38":
+  FLTUND: 1
+"Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp:120":
   FLTUND: 1

Core/include/Acts/Vertexing/AdaptiveGridDensityVertexFinder.ipp

@@ -29,8 +29,7 @@ auto Acts::AdaptiveGridDensityVertexFinder<trkGridSize, vfitter_t>::find(
       // No tracks were removed anymore
       // Return empty seed, i.e. vertex at constraint position
       // (Note: Upstream finder should check for this break condition)
-      std::vector<Vertex<InputTrack_t>> seedVec{
-          vertexingOptions.vertexConstraint};
+      std::vector<Vertex<InputTrack_t>> seedVec{vertexingOptions.constraint};
       return seedVec;
     }
   } else {
@@ -81,12 +80,11 @@ auto Acts::AdaptiveGridDensityVertexFinder<trkGridSize, vfitter_t>::find(
   }
 
   // Construct output vertex
-  Vector3 seedPos =
-      vertexingOptions.vertexConstraint.position() + Vector3(0., 0., z);
+  Vector3 seedPos = vertexingOptions.constraint.position() + Vector3(0., 0., z);
 
   Vertex<InputTrack_t> returnVertex = Vertex<InputTrack_t>(seedPos);
 
-  SquareMatrix4 seedCov = vertexingOptions.vertexConstraint.fullCovariance();
+  SquareMatrix4 seedCov = vertexingOptions.constraint.fullCovariance();
 
   if (width != 0.) {
     // Use z-constraint from seed width

Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.hpp

@@ -81,10 +81,6 @@ class AdaptiveMultiVertexFinder {
 
     std::shared_ptr<const MagneticFieldProvider> bField;
 
-    // Use a beam spot constraint, vertexConstraint in VertexingOptions
-    // has to be set in this case
-    bool useBeamSpotConstraint = true;
-
     // Max z interval used for adding tracks to fit:
     // When adding a new vertex to the multi vertex fit,
     // only the tracks whose z at PCA is closer
@@ -249,8 +245,10 @@ class AdaptiveMultiVertexFinder {
   /// @brief Sets constraint vertex after seeding
   ///
   /// @param currentConstraint Vertex constraint
+  /// @param useVertexConstraintInFit Indicates whether constraint is used during vertex fit
   /// @param seedVertex Seed vertex
   void setConstraintAfterSeeding(Vertex<InputTrack_t>& currentConstraint,
+                                 bool useVertexConstraintInFit,
                                  Vertex<InputTrack_t>& seedVertex) const;
 
   /// @brief Calculates the IP significance of a track to a given vertex
@@ -318,12 +316,13 @@ class AdaptiveMultiVertexFinder {
   /// @param vtx The vertex candidate
   /// @param seedTracks The seed tracks
   /// @param fitterState The vertex fitter state
+  /// @param useVertexConstraintInFit Indicates whether constraint is used in the vertex fit
   ///
   /// @return pair(nCompatibleTracks, isGoodVertex)
   std::pair<int, bool> checkVertexAndCompatibleTracks(
       Vertex<InputTrack_t>& vtx,
       const std::vector<const InputTrack_t*>& seedTracks,
-      FitterState_t& fitterState) const;
+      FitterState_t& fitterState, bool useVertexConstraintInFit) const;
 
   /// @brief Method that removes all tracks that are compatible with
   /// current vertex from seedTracks

Core/include/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp

@@ -44,7 +44,7 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::find(
     } else {
       searchTracks = seedTracks;
     }
-    Vertex<InputTrack_t> currentConstraint = vertexingOptions.vertexConstraint;
+    Vertex<InputTrack_t> currentConstraint = vertexingOptions.constraint;
     // Retrieve seed vertex from all remaining seedTracks
     auto seedResult = doSeeding(seedTracks, currentConstraint, vertexingOptions,
                                 seedFinderState, removedSeedTracks);
@@ -59,7 +59,7 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::find(
     ACTS_DEBUG("Position of current vertex candidate after seeding: "
                << vtxCandidate.fullPosition().transpose());
     if (vtxCandidate.position().z() ==
-        vertexingOptions.vertexConstraint.position().z()) {
+        vertexingOptions.constraint.position().z()) {
       ACTS_DEBUG(
           "No seed found anymore. Break and stop primary vertex finding.");
       allVertices.pop_back();
@@ -97,7 +97,8 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::find(
                << vtxCandidate.fullPosition().transpose());
     // Check if vertex is good vertex
     auto [nCompatibleTracks, isGoodVertex] =
-        checkVertexAndCompatibleTracks(vtxCandidate, seedTracks, fitterState);
+        checkVertexAndCompatibleTracks(vtxCandidate, seedTracks, fitterState,
+                                       vertexingOptions.useConstraintInFit);
 
     ACTS_DEBUG("Vertex is good vertex: " << isGoodVertex);
     if (nCompatibleTracks > 0) {
@@ -143,7 +144,7 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::doSeeding(
     const std::vector<const InputTrack_t*>& removedSeedTracks) const
     -> Result<Vertex<InputTrack_t>> {
   VertexingOptions<InputTrack_t> seedOptions = vertexingOptions;
-  seedOptions.vertexConstraint = currentConstraint;
+  seedOptions.constraint = currentConstraint;
 
   if constexpr (NeedsRemovedTracks<typename sfinder_t::State>::value) {
     seedFinderState.tracksToRemove = removedSeedTracks;
@@ -159,20 +160,18 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::doSeeding(
 
   Vertex<InputTrack_t> seedVertex = (*seedResult).back();
   // Update constraints according to seed vertex
-  setConstraintAfterSeeding(currentConstraint, seedVertex);
+  setConstraintAfterSeeding(currentConstraint, seedOptions.useConstraintInFit,
+                            seedVertex);
 
   return seedVertex;
 }
 
 template <typename vfitter_t, typename sfinder_t>
 auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::
     setConstraintAfterSeeding(Vertex<InputTrack_t>& currentConstraint,
+                              bool useVertexConstraintInFit,
                               Vertex<InputTrack_t>& seedVertex) const -> void {
-  if (m_cfg.useBeamSpotConstraint) {
-    if (currentConstraint.fullCovariance() == SquareMatrix4::Zero()) {
-      ACTS_WARNING(
-          "No constraint provided, but useBeamSpotConstraint set to true.");
-    }
+  if (useVertexConstraintInFit) {
     if (not m_cfg.useSeedConstraint) {
       // Set seed vertex constraint to old constraint before seeding
       seedVertex.setFullCovariance(currentConstraint.fullCovariance());
@@ -350,7 +349,8 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::
     checkVertexAndCompatibleTracks(
         Vertex<InputTrack_t>& vtx,
         const std::vector<const InputTrack_t*>& seedTracks,
-        FitterState_t& fitterState) const -> std::pair<int, bool> {
+        FitterState_t& fitterState, bool useVertexConstraintInFit) const
+    -> std::pair<int, bool> {
   bool isGoodVertex = false;
   int nCompatibleTracks = 0;
   for (const auto& trk : fitterState.vtxInfoMap[&vtx].trackLinks) {
@@ -370,7 +370,7 @@ auto Acts::AdaptiveMultiVertexFinder<vfitter_t, sfinder_t>::
         nCompatibleTracks++;
         ACTS_DEBUG("Compatible track found.");
 
-        if (m_cfg.addSingleTrackVertices && m_cfg.useBeamSpotConstraint) {
+        if (m_cfg.addSingleTrackVertices && useVertexConstraintInFit) {
           isGoodVertex = true;
           break;
         }

Core/include/Acts/Vertexing/FullBilloirVertexFitter.ipp

@@ -84,20 +84,16 @@ Acts::FullBilloirVertexFitter<input_track_t, linearizer_t>::fit(
     ndf = 1;
   }
 
-  // Determine if we do constraint fit or not by checking if an
-  // invertible non-zero constraint vertex covariance is given
-  bool isConstraintFit = false;
-  if (vertexingOptions.vertexConstraint.covariance().determinant() != 0) {
-    isConstraintFit = true;
-    // Since we add a term to the chi2 when adding a vertex constraint (see Ref.
-    // (1)), the number of degrees of freedom increases
+  // Since we add a term to the chi2 when adding a vertex constraint (see Ref.
+  // (1)), the number of degrees of freedom increases
+  if (vertexingOptions.useConstraintInFit) {
     ndf += 3;
   }
 
   std::vector<BilloirTrack<input_track_t>> billoirTracks;
   std::vector<Vector3> trackMomenta;
   // Initial guess of the 4D vertex position
-  Vector4 linPoint = vertexingOptions.vertexConstraint.fullPosition();
+  Vector4 linPoint = vertexingOptions.constraint.fullPosition();
   Vertex<input_track_t> fittedVertex;
 
   for (int nIter = 0; nIter < m_cfg.maxIterations; ++nIter) {
@@ -188,22 +184,21 @@ Acts::FullBilloirVertexFitter<input_track_t, linearizer_t>::fit(
     // Cov(V) = Cov(deltaV)), see Ref. (1).
     // invCovV = A-sum{Bi*Ci^-1*Bi^T}
     SquareMatrix4 invCovV = billoirVertex.A - billoirVertex.sumBCinvBt;
-    if (isConstraintFit) {
+    if (vertexingOptions.useConstraintInFit) {
       // Position of vertex constraint in Billoir frame (i.e., in coordinate
       // system with origin at linPoint). This will be 0 for first iteration but
       // != 0 from second on since our first guess for the vertex position is
       // the vertex constraint position.
       Vector4 posInBilloirFrame =
-          vertexingOptions.vertexConstraint.fullPosition() - linPoint;
+          vertexingOptions.constraint.fullPosition() - linPoint;
 
       // For vertex constraint: T -> T + Cb^-1 (b - V0) where Cb is the
       // covariance matrix of the constraint, b is the constraint position, and
       // V0 is the vertex estimate (see Ref. (1)).
-      deltaVFac +=
-          vertexingOptions.vertexConstraint.fullCovariance().inverse() *
-          posInBilloirFrame;
+      deltaVFac += vertexingOptions.constraint.fullCovariance().inverse() *
+                   posInBilloirFrame;
       // For vertex constraint: A -> A + Cb^-1
-      invCovV += vertexingOptions.vertexConstraint.fullCovariance().inverse();
+      invCovV += vertexingOptions.constraint.fullCovariance().inverse();
     }
 
     // Covariance matrix of the 4D vertex position
@@ -283,17 +278,16 @@ Acts::FullBilloirVertexFitter<input_track_t, linearizer_t>::fit(
 
     // Add an additional term to chi2 if there is a vertex constraint (see Ref.
     // (1))
-    if (isConstraintFit) {
+    if (vertexingOptions.useConstraintInFit) {
       // Position of vertex constraint in Billoir frame (i.e., in coordinate
       // system with origin at linPoint).
       Vector4 posInBilloirFrame =
-          vertexingOptions.vertexConstraint.fullPosition() - linPoint;
+          vertexingOptions.constraint.fullPosition() - linPoint;
 
       newChi2 +=
           (posInBilloirFrame.transpose())
-              .dot(
-                  vertexingOptions.vertexConstraint.fullCovariance().inverse() *
-                  posInBilloirFrame);
+              .dot(vertexingOptions.constraint.fullCovariance().inverse() *
+                   posInBilloirFrame);
     }
 
     if (!std::isnormal(newChi2)) {

Core/include/Acts/Vertexing/GridDensityVertexFinder.ipp

@@ -30,8 +30,7 @@ auto Acts::GridDensityVertexFinder<mainGridSize, trkGridSize, vfitter_t>::find(
       // No tracks were removed anymore
       // Return empty seed, i.e. vertex at constraint position
       // (Note: Upstream finder should check for this break condition)
-      std::vector<Vertex<InputTrack_t>> seedVec{
-          vertexingOptions.vertexConstraint};
+      std::vector<Vertex<InputTrack_t>> seedVec{vertexingOptions.constraint};
       return seedVec;
     }
   } else {
@@ -81,12 +80,11 @@ auto Acts::GridDensityVertexFinder<mainGridSize, trkGridSize, vfitter_t>::find(
   }
 
   // Construct output vertex
-  Vector3 seedPos =
-      vertexingOptions.vertexConstraint.position() + Vector3(0., 0., z);
+  Vector3 seedPos = vertexingOptions.constraint.position() + Vector3(0., 0., z);
 
   Vertex<InputTrack_t> returnVertex = Vertex<InputTrack_t>(seedPos);
 
-  SquareMatrix4 seedCov = vertexingOptions.vertexConstraint.fullCovariance();
+  SquareMatrix4 seedCov = vertexingOptions.constraint.fullCovariance();
 
   if (width != 0.) {
     // Use z-constraint from seed width

Core/include/Acts/Vertexing/IterativeVertexFinder.hpp

@@ -95,7 +95,6 @@ class IterativeVertexFinder {
     IPEstimator ipEst;
 
     // Vertex finder configuration variables
-    bool useBeamConstraint = false;
     double significanceCutSeeding = 10;
     double maximumChi2cutForSeeding = 36.;
     int maxVertices = 50;

Core/include/Acts/Vertexing/IterativeVertexFinder.ipp

@@ -32,7 +32,7 @@ auto Acts::IterativeVertexFinder<vfitter_t, sfinder_t>::find(
     const auto& seedVertex = *seedRes;
 
     if (seedVertex.fullPosition()[eZ] ==
-        vertexingOptions.vertexConstraint.position().z()) {
+        vertexingOptions.constraint.position().z()) {
       ACTS_DEBUG("No more seed found. Break and stop primary vertex finding.");
       break;
     }
@@ -58,15 +58,16 @@ auto Acts::IterativeVertexFinder<vfitter_t, sfinder_t>::find(
     Vertex<InputTrack_t> currentVertex;
     Vertex<InputTrack_t> currentSplitVertex;
 
-    if (m_cfg.useBeamConstraint && !perigeesToFit.empty()) {
+    if (vertexingOptions.useConstraintInFit && !perigeesToFit.empty()) {
       auto fitResult = m_cfg.vertexFitter.fit(
           perigeesToFit, m_cfg.linearizer, vertexingOptions, state.fitterState);
       if (fitResult.ok()) {
         currentVertex = std::move(*fitResult);
       } else {
         return fitResult.error();
       }
-    } else if (!m_cfg.useBeamConstraint && perigeesToFit.size() > 1) {
+    } else if (!vertexingOptions.useConstraintInFit &&
+               perigeesToFit.size() > 1) {
       auto fitResult = m_cfg.vertexFitter.fit(
           perigeesToFit, m_cfg.linearizer, vertexingOptions, state.fitterState);
       if (fitResult.ok()) {
@@ -97,9 +98,10 @@ auto Acts::IterativeVertexFinder<vfitter_t, sfinder_t>::find(
     int nTracksAtVertex = countSignificantTracks(currentVertex);
     int nTracksAtSplitVertex = countSignificantTracks(currentSplitVertex);
 
-    bool isGoodVertex =
-        ((!m_cfg.useBeamConstraint && ndf > 0 && nTracksAtVertex >= 2) ||
-         (m_cfg.useBeamConstraint && ndf > 3 && nTracksAtVertex >= 2));
+    bool isGoodVertex = ((!vertexingOptions.useConstraintInFit && ndf > 0 &&
+                          nTracksAtVertex >= 2) ||
+                         (vertexingOptions.useConstraintInFit && ndf > 3 &&
+                          nTracksAtVertex >= 2));
 
     if (!isGoodVertex) {
       removeAllTracks(perigeesToFit, seedTracks);
@@ -502,15 +504,15 @@ Acts::IterativeVertexFinder<vfitter_t, sfinder_t>::reassignTracksToNewVertex(
   // set first to default vertex to be able to check if still good vertex
   // later
   currentVertex = Vertex<InputTrack_t>();
-  if (m_cfg.useBeamConstraint && !perigeesToFit.empty()) {
+  if (vertexingOptions.useConstraintInFit && !perigeesToFit.empty()) {
     auto fitResult = m_cfg.vertexFitter.fit(
         perigeesToFit, m_cfg.linearizer, vertexingOptions, state.fitterState);
     if (fitResult.ok()) {
       currentVertex = std::move(*fitResult);
     } else {
       return Result<bool>::success(false);
     }
-  } else if (!m_cfg.useBeamConstraint && perigeesToFit.size() > 1) {
+  } else if (!vertexingOptions.useConstraintInFit && perigeesToFit.size() > 1) {
     auto fitResult = m_cfg.vertexFitter.fit(
         perigeesToFit, m_cfg.linearizer, vertexingOptions, state.fitterState);
     if (fitResult.ok()) {
@@ -526,9 +528,10 @@ Acts::IterativeVertexFinder<vfitter_t, sfinder_t>::reassignTracksToNewVertex(
   // Number of significant tracks
   int nTracksAtVertex = countSignificantTracks(currentVertex);
 
-  bool isGoodVertex =
-      ((!m_cfg.useBeamConstraint && ndf > 0 && nTracksAtVertex >= 2) ||
-       (m_cfg.useBeamConstraint && ndf > 3 && nTracksAtVertex >= 2));
+  bool isGoodVertex = ((!vertexingOptions.useConstraintInFit && ndf > 0 &&
+                        nTracksAtVertex >= 2) ||
+                       (vertexingOptions.useConstraintInFit && ndf > 3 &&
+                        nTracksAtVertex >= 2));
 
   if (!isGoodVertex) {
     removeAllTracks(perigeesToFit, seedTracks);

Core/include/Acts/Vertexing/TrackDensityVertexFinder.ipp

@@ -22,12 +22,11 @@ auto Acts::TrackDensityVertexFinder<vfitter_t, track_density_t>::find(
 
   // Calculate seed position
   // Note: constraint position is (0,0,0) if no constraint provided
-  Vector3 seedPos =
-      vertexingOptions.vertexConstraint.position() + Vector3(0., 0., z);
+  Vector3 seedPos = vertexingOptions.constraint.position() + Vector3(0., 0., z);
 
   Vertex<InputTrack_t> returnVertex = Vertex<InputTrack_t>(seedPos);
 
-  SquareMatrix3 seedCov = vertexingOptions.vertexConstraint.covariance();
+  SquareMatrix3 seedCov = vertexingOptions.constraint.covariance();
 
   // Check if a constraint is provided and set the new z position constraint
   if (seedCov != SquareMatrix3::Zero() && std::isnormal(zAndWidth.second)) {