refactor: KalmanVertex(Track)Updater interface change

Core/include/Acts/Vertexing/AdaptiveMultiVertexFitter.ipp

@@ -6,7 +6,6 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-#include "Acts/Vertexing/KalmanVertexTrackUpdater.hpp"
 #include "Acts/Vertexing/KalmanVertexUpdater.hpp"
 #include "Acts/Vertexing/VertexingError.hpp"
 
@@ -291,11 +290,8 @@ inline Acts::Result<void> Acts::AdaptiveMultiVertexFitter::setWeightsAndUpdate(
         // Update the vertex with the new track. The second template argument
         // corresponds to the number of fitted vertex dimensions (i.e., 3 if we
         // only fit spatial coordinates and 4 if we also fit time).
-        if (m_cfg.useTime) {
-          KalmanVertexUpdater::updateVertexWithTrack<4>(*vtx, trkAtVtx);
-        } else {
-          KalmanVertexUpdater::updateVertexWithTrack<3>(*vtx, trkAtVtx);
-        }
+        KalmanVertexUpdater::updateVertexWithTrack(*vtx, trkAtVtx,
+                                                   m_cfg.useTime ? 4 : 3);
       } else {
         ACTS_VERBOSE("Track weight too low. Skip track.");
       }
@@ -354,9 +350,8 @@ inline void Acts::AdaptiveMultiVertexFitter::doVertexSmoothing(
         // vertex. The second template argument corresponds to the number of
         // fitted vertex dimensions (i.e., 3 if we only fit spatial coordinates
         // and 4 if we also fit time).
-        KalmanVertexTrackUpdater::update(trkAtVtx, vtx->fullPosition(),
-                                         vtx->fullCovariance(),
-                                         m_cfg.useTime ? 4 : 3);
+        KalmanVertexUpdater::updateTrackWithVertex(trkAtVtx, *vtx,
+                                                   m_cfg.useTime ? 4 : 3);
       }
     }
   }

Core/include/Acts/Vertexing/KalmanVertexUpdater.hpp

@@ -1,19 +1,18 @@
 // This file is part of the Acts project.
 //
-// Copyright (C) 2019-2023 CERN for the benefit of the Acts project
+// Copyright (C) 2019-2024 CERN for the benefit of the Acts project
 //
 // This Source Code Form is subject to the terms of the Mozilla Public
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 #pragma once
 
-#include "Acts/Definitions/Algebra.hpp"
-#include "Acts/Utilities/Result.hpp"
-#include "Acts/Vertexing/TrackAtVertex.hpp"
-#include "Acts/Vertexing/Vertex.hpp"
-
 namespace Acts {
+
+class Vertex;
+struct TrackAtVertex;
+
 namespace KalmanVertexUpdater {
 
 /// KalmanVertexUpdater
@@ -35,91 +34,36 @@ namespace KalmanVertexUpdater {
 /// CERN-THESIS-2010-027
 /// Section 5.3.5
 
-/// Cache object, the comments indicate the names of the variables in Ref. (1)
-/// @tparam nDimVertex number of dimensions of the vertex. Can be 3 (if we only
-/// fit its spatial coordinates) or 4 (if we also fit time).
-template <unsigned int nDimVertex>
-struct Cache {
-  using VertexVector = ActsVector<nDimVertex>;
-  using VertexMatrix = ActsSquareMatrix<nDimVertex>;
-  // \tilde{x_k}
-  VertexVector newVertexPos = VertexVector::Zero();
-  // C_k
-  VertexMatrix newVertexCov = VertexMatrix::Zero();
-  // C_k^-1
-  VertexMatrix newVertexWeight = VertexMatrix::Zero();
-  // C_{k-1}^-1
-  VertexMatrix oldVertexWeight = VertexMatrix::Zero();
-  // W_k
-  SquareMatrix3 wMat = SquareMatrix3::Zero();
-};
-
 /// @brief Updates vertex with knowledge of new track
 /// @note KalmanVertexUpdater updates the vertex when trk is added to the fit.
 /// However, it does not add the track to the TrackAtVertex list. This to be
 /// done manually after calling the method.
 ///
-/// @tparam nDimVertex number of dimensions of the vertex. Can be 3 (if we only
-/// fit its spatial coordinates) or 4 (if we also fit time).
 ///
 /// @param vtx Vertex to be updated
 /// @param trk Track to be used for updating the vertex
-template <unsigned int nDimVertex>
-void updateVertexWithTrack(Vertex& vtx, TrackAtVertex& trk);
-
-namespace detail {
-void updateVertexWithTrack(Vector4& vtxPos, SquareMatrix4& vtxCov,
-                           std::pair<double, double>& fitQuality,
-                           TrackAtVertexRef trk, int sign,
+/// @param nDimVertex number of dimensions of the vertex. Can be 3 (if we only
+/// fit its spatial coordinates) or 4 (if we also fit time).
+void updateVertexWithTrack(Vertex& vtx, TrackAtVertex& trk,
                            unsigned int nDimVertex);
 
-// These two functions only exist so we can compile calculateUpdate in a
-// compilation unit
-void calculateUpdate3(const Vector4& vtxPos, const SquareMatrix4& vtxCov,
-                      const Acts::LinearizedTrack& linTrack,
-                      const double trackWeight, const int sign,
-                      Cache<3>& cache);
-
-void calculateUpdate4(const Vector4& vtxPos, const SquareMatrix4& vtxCov,
-                      const Acts::LinearizedTrack& linTrack,
-                      const double trackWeight, const int sign,
-                      Cache<4>& cache);
-}  // namespace detail
+/// Based on
+/// Ref. (1):
+/// R. Frühwirth et al.
+/// Vertex reconstruction and track bundling at the lep collider using robust
+/// algorithms
+/// Computer Physics Comm.: 96 (1996) 189
+/// Chapter 2.1
 
-/// @brief Calculates updated vertex position and covariance as well as the
-/// updated track momentum when adding/removing linTrack. Saves the result in
-/// cache.
+/// @brief Refits a single track with the knowledge of
+/// the vertex it has originated from
 ///
-/// @tparam nDimVertex number of dimensions of the vertex. Can be 3 (if we only
+/// @param track Track to update
+/// @param vtx Vertex to use for updating the track
+/// @param nDimVertex number of dimensions of the vertex. Can be 3 (if we only
 /// fit its spatial coordinates) or 4 (if we also fit time).
-///
-/// @param vtxPos Vertex position
-/// @param vtxCov Vertex covariance matrix
-/// @param linTrack Linearized track to be added or removed
-/// @param trackWeight Track weight
-/// @param sign +1 (add track) or -1 (remove track)
-/// @note Tracks are removed during the smoothing procedure to compute
-/// the chi2 of the track wrt the updated vertex position
-/// @param[in,out] cache A cache to store the results of this function
-template <unsigned int nDimVertex>
-void calculateUpdate(const Vector4& vtxPos, const SquareMatrix4& vtxCov,
-                     const Acts::LinearizedTrack& linTrack,
-                     const double trackWeight, const int sign,
-                     Cache<nDimVertex>& cache) {
-  static_assert(nDimVertex == 3 || nDimVertex == 4,
-                "The vertex dimension must either be 3 (when fitting the "
-                "spatial coordinates) or 4 (when fitting the spatial "
-                "coordinates + time).");
-  if constexpr (nDimVertex == 3) {
-    detail::calculateUpdate3(vtxPos, vtxCov, linTrack, trackWeight, sign,
-                             cache);
-  } else if constexpr (nDimVertex == 4) {
-    detail::calculateUpdate4(vtxPos, vtxCov, linTrack, trackWeight, sign,
-                             cache);
-  }
-}
-
-}  // Namespace KalmanVertexUpdater
-}  // Namespace Acts
+void updateTrackWithVertex(TrackAtVertex& track, const Vertex& vtx,
+                           unsigned int nDimVertex);
 
-#include "KalmanVertexUpdater.ipp"
+}  // namespace KalmanVertexUpdater
+}  // namespace Acts

Core/include/Acts/Vertexing/TrackAtVertex.hpp

@@ -124,25 +124,6 @@ struct TrackAtVertex {
   bool isLinearized = false;
 };
 
-struct TrackAtVertexRef {
-  BoundTrackParameters& fittedParams;
-  double& chi2Track;
-  double& ndf;
-  double& vertexCompatibility;
-  double& trackWeight;
-  LinearizedTrack& linearizedState;
-  bool isLinearized;
-
-  TrackAtVertexRef(TrackAtVertex& track)
-      : fittedParams(track.fittedParams),
-        chi2Track(track.chi2Track),
-        ndf(track.ndf),
-        vertexCompatibility(track.vertexCompatibility),
-        trackWeight(track.trackWeight),
-        linearizedState(track.linearizedState),
-        isLinearized(track.isLinearized) {}
-};
-
 }  // namespace Acts
 
 template <>

Core/src/Vertexing/CMakeLists.txt

@@ -2,7 +2,6 @@ target_sources(
   ActsCore
   PRIVATE
     AdaptiveGridTrackDensity.cpp
-    KalmanVertexTrackUpdater.cpp
     KalmanVertexUpdater.cpp
     FsmwMode1dFinder.cpp
     VertexingError.cpp