refactor!: Remove CovarianceTransport

Core/src/Propagator/CMakeLists.txt

@@ -1,7 +1,6 @@
 target_sources(
   ActsCore
   PRIVATE
-    CovarianceTransport.cpp
     EigenStepperError.cpp
     MultiStepperError.cpp
     PropagatorError.cpp

Plugins/EDM4hep/include/Acts/Plugins/EDM4hep/EDM4hepUtil.hpp

@@ -18,7 +18,6 @@
 #include "Acts/EventData/detail/TransformationBoundToFree.hpp"
 #include "Acts/EventData/detail/TransformationFreeToBound.hpp"
 #include "Acts/Geometry/GeometryContext.hpp"
-#include "Acts/Propagator/CovarianceTransport.hpp"
 #include "Acts/Surfaces/PerigeeSurface.hpp"
 #include "Acts/Surfaces/Surface.hpp"
 #include "Acts/Utilities/Logger.hpp"

Plugins/EDM4hep/src/EDM4hepUtil.cpp

@@ -8,6 +8,8 @@
 
 #include "Acts/Plugins/EDM4hep/EDM4hepUtil.hpp"
 
+#include "Acts/Definitions/Algebra.hpp"
+#include "Acts/Definitions/TrackParametrization.hpp"
 #include "Acts/Definitions/Units.hpp"
 #include "Acts/EventData/MultiTrajectory.hpp"
 #include "Acts/EventData/MultiTrajectoryHelpers.hpp"
@@ -115,14 +117,8 @@ Parameters convertTrackParametersToEdm4hep(const Acts::GeometryContext& gctx,
 
   std::shared_ptr<const Acts::Surface> refSurface =
       params.referenceSurface().getSharedPtr();
-
   Acts::BoundVector targetPars = params.parameters();
-  std::optional<Acts::FreeVector> freePars;
-
-  auto makeFreePars = [&]() {
-    return Acts::detail::transformBoundToFreeParameters(
-        params.referenceSurface(), gctx, params.parameters());
-  };
+  std::optional<Acts::BoundSquareMatrix> targetCov = params.covariance();
 
   // If the reference surface is a perigee surface, we use that. Otherwise
   // we create a new perigee surface at the global position of the track
@@ -133,36 +129,31 @@ Parameters convertTrackParametersToEdm4hep(const Acts::GeometryContext& gctx,
     // We need to convert to the target parameters
     // Keep the free parameters around we might need them for the covariance
     // conversion
-    freePars = makeFreePars();
-    targetPars = Acts::detail::transformFreeToBoundParameters(freePars.value(),
+    Acts::FreeVector freePars = Acts::detail::transformBoundToFreeParameters(
+        params.referenceSurface(), gctx, params.parameters());
+    targetPars = Acts::detail::transformFreeToBoundParameters(freePars,
                                                               *refSurface, gctx)
                      .value();
+
+    if (targetCov) {
+      // We need to convert the covariance as well
+      Acts::BoundToFreeMatrix boundToFree =
+          params.referenceSurface().boundToFreeJacobian(gctx, targetPars);
+      Acts::FreeToBoundMatrix freeToBound =
+          refSurface->freeToBoundJacobian(gctx, freePars);
+      Acts::BoundSquareMatrix boundToBound = freeToBound * boundToFree;
+      targetCov = boundToBound * targetCov.value() * boundToBound.transpose();
+    }
   }
 
   Parameters result;
   result.surface = refSurface;
 
   // Only run covariance conversion if we have a covariance input
-  if (params.covariance()) {
-    auto boundToFree =
-        refSurface->boundToFreeJacobian(gctx, params.parameters());
-    Acts::FreeMatrix freeCov =
-        boundToFree * params.covariance().value() * boundToFree.transpose();
-
-    // ensure we have free pars
-    if (!freePars.has_value()) {
-      freePars = makeFreePars();
-    }
-
-    Acts::CovarianceCache covCache{freePars.value(), freeCov};
-    auto [varNewCov, varNewJac] = Acts::transportCovarianceToBound(
-        gctx, *refSurface, freePars.value(), covCache);
-    auto targetCov = std::get<Acts::BoundSquareMatrix>(varNewCov);
-
+  if (targetCov) {
     Acts::ActsSquareMatrix<6> J = jacobianToEdm4hep(
         targetPars[eBoundTheta], targetPars[eBoundQOverP], Bz);
-    Acts::ActsSquareMatrix<6> cIn = targetCov.template topLeftCorner<6, 6>();
-    result.covariance = J * cIn * J.transpose();
+    result.covariance = J * targetCov.value() * J.transpose();
   }
 
   result.values[0] = targetPars[Acts::eBoundLoc0];

Tests/Benchmarks/CMakeLists.txt

@@ -23,7 +23,6 @@ endmacro()
 add_benchmark(AtlasStepper AtlasStepperBenchmark.cpp)
 add_benchmark(BoundaryCheck BoundaryCheckBenchmark.cpp)
 add_benchmark(BinUtility BinUtilityBenchmark.cpp)
-add_benchmark(CovarianceTransport CovarianceTransportBenchmark.cpp)
 add_benchmark(EigenStepper EigenStepperBenchmark.cpp)
 add_benchmark(SolenoidField SolenoidFieldBenchmark.cpp)
 add_benchmark(SurfaceIntersection SurfaceIntersectionBenchmark.cpp)

Tests/UnitTests/Core/Propagator/CMakeLists.txt

@@ -2,7 +2,6 @@ add_unittest(AtlasStepper AtlasStepperTests.cpp)
 add_unittest(Auctioneer AuctioneerTests.cpp)
 add_unittest(ConstrainedStep ConstrainedStepTests.cpp)
 add_unittest(CovarianceEngine CovarianceEngineTests.cpp)
-add_unittest(CovarianceTransport CovarianceTransportTests.cpp)
 add_unittest(DirectNavigator DirectNavigatorTests.cpp)
 add_unittest(Extrapolator ExtrapolatorTests.cpp)
 add_unittest(Jacobian JacobianTests.cpp)