refactor: Optional curvilinear state in Propagator

Core/include/Acts/Propagator/Propagator.hpp

@@ -353,6 +353,7 @@ class Propagator final {
   ///
   /// @param [in] start initial track parameters to propagate
   /// @param [in] options Propagation options, type Options<,>
+  /// @param [in] makeCurvilinear Produce curvilinear parameters at the end of the propagation
   ///
   /// @return Propagation result containing the propagation status, final
   ///         track parameters, and output of actions (if they produce any)
@@ -362,8 +363,8 @@ class Propagator final {
   Result<
       action_list_t_result_t<CurvilinearTrackParameters,
                              typename propagator_options_t::action_list_type>>
-  propagate(const parameters_t& start,
-            const propagator_options_t& options) const;
+  propagate(const parameters_t& start, const propagator_options_t& options,
+            bool makeCurvilinear = true) const;
 
   /// @brief Propagate track parameters
   ///
@@ -378,6 +379,7 @@ class Propagator final {
   ///
   /// @param [in] start initial track parameters to propagate
   /// @param [in] options Propagation options, type Options<,>
+  /// @param [in] makeCurvilinear Produce curvilinear parameters at the end of the propagation
   /// @param [in] inputResult an existing result object to start from
   ///
   /// @return Propagation result containing the propagation status, final
@@ -390,6 +392,7 @@ class Propagator final {
                              typename propagator_options_t::action_list_type>>
   propagate(
       const parameters_t& start, const propagator_options_t& options,
+      bool makeCurvilinear,
       action_list_t_result_t<CurvilinearTrackParameters,
                              typename propagator_options_t::action_list_type>&&
           inputResult) const;

Core/include/Acts/Propagator/Propagator.ipp

@@ -90,8 +90,9 @@ auto Acts::Propagator<S, N>::propagate_impl(propagator_state_t& state,
 template <typename S, typename N>
 template <typename parameters_t, typename propagator_options_t,
           typename path_aborter_t>
-auto Acts::Propagator<S, N>::propagate(
-    const parameters_t& start, const propagator_options_t& options) const
+auto Acts::Propagator<S, N>::propagate(const parameters_t& start,
+                                       const propagator_options_t& options,
+                                       bool makeCurvilinear) const
     -> Result<action_list_t_result_t<
         CurvilinearTrackParameters,
         typename propagator_options_t::action_list_type>> {
@@ -107,14 +108,15 @@ auto Acts::Propagator<S, N>::propagate(
                              typename propagator_options_t::action_list_type>;
 
   return propagate<parameters_t, propagator_options_t, path_aborter_t>(
-      start, options, ResultType{});
+      start, options, makeCurvilinear, ResultType{});
 }
 
 template <typename S, typename N>
 template <typename parameters_t, typename propagator_options_t,
           typename path_aborter_t>
 auto Acts::Propagator<S, N>::propagate(
     const parameters_t& start, const propagator_options_t& options,
+    bool makeCurvilinear,
     action_list_t_result_t<CurvilinearTrackParameters,
                            typename propagator_options_t::action_list_type>&&
         inputResult) const
@@ -162,13 +164,16 @@ auto Acts::Propagator<S, N>::propagate(
   // Perform the actual propagation & check its outcome
   auto result = propagate_impl<ResultType>(state, inputResult);
   if (result.ok()) {
-    /// Convert into return type and fill the result object
-    auto curvState = m_stepper.curvilinearState(state.stepping);
-    // Fill the end parameters
-    inputResult.endParameters = std::get<CurvilinearTrackParameters>(curvState);
-    // Only fill the transport jacobian when covariance transport was done
-    if (state.stepping.covTransport) {
-      inputResult.transportJacobian = std::get<Jacobian>(curvState);
+    if (makeCurvilinear) {
+      /// Convert into return type and fill the result object
+      auto curvState = m_stepper.curvilinearState(state.stepping);
+      // Fill the end parameters
+      inputResult.endParameters =
+          std::get<CurvilinearTrackParameters>(curvState);
+      // Only fill the transport jacobian when covariance transport was done
+      if (state.stepping.covTransport) {
+        inputResult.transportJacobian = std::get<Jacobian>(curvState);
+      }
     }
     return Result<ResultType>::success(std::forward<ResultType>(inputResult));
   } else {

Core/include/Acts/TrackFinding/CombinatorialKalmanFilter.hpp

@@ -1380,7 +1380,7 @@ class CombinatorialKalmanFilter {
     r.stateBuffer->clear();
 
     auto result = m_propagator.template propagate(
-        initialParameters, propOptions, std::move(inputResult));
+        initialParameters, propOptions, false, std::move(inputResult));
 
     if (!result.ok()) {
       ACTS_ERROR("Propapation failed: " << result.error() << " "

Core/include/Acts/TrackFitting/GaussianSumFitter.hpp

@@ -289,10 +289,10 @@ struct GaussianSumFitter {
             sParameters.referenceSurface().getSharedPtr(),
             sParameters.parameters(), sParameters.covariance());
 
-        return m_propagator.propagate(params, fwdPropOptions,
+        return m_propagator.propagate(params, fwdPropOptions, false,
                                       std::move(inputResult));
       } else {
-        return m_propagator.propagate(sParameters, fwdPropOptions,
+        return m_propagator.propagate(sParameters, fwdPropOptions, false,
                                       std::move(inputResult));
       }
     }();

Core/include/Acts/TrackFitting/GlobalChiSquareFitter.hpp

@@ -519,8 +519,8 @@ class Gx2Fitter {
 
       r.fittedStates = &trackContainer.trackStateContainer();
       // propagate with params and return jacobians and residuals
-      auto result = m_propagator.template propagate(params, propagatorOptions,
-                                                    std::move(inputResult));
+      auto result = m_propagator.template propagate(
+          params, propagatorOptions, true, std::move(inputResult));
 
       // TODO Improve Propagator + Actor [allocate before loop], rewrite
       // makeMeasurements

Core/include/Acts/TrackFitting/KalmanFitter.hpp

@@ -1093,8 +1093,8 @@ class KalmanFitter {
     r.fittedStates = &trackContainer.trackStateContainer();
 
     // Run the fitter
-    auto result = m_propagator.template propagate(sParameters, kalmanOptions,
-                                                  std::move(inputResult));
+    auto result = m_propagator.template propagate(
+        sParameters, kalmanOptions, false, std::move(inputResult));
 
     if (!result.ok()) {
       ACTS_ERROR("Propapation failed: " << result.error());
@@ -1232,8 +1232,8 @@ class KalmanFitter {
     r.fittedStates = &trackContainer.trackStateContainer();
 
     // Run the fitter
-    auto result = m_propagator.template propagate(sParameters, kalmanOptions,
-                                                  std::move(inputResult));
+    auto result = m_propagator.template propagate(
+        sParameters, kalmanOptions, false, std::move(inputResult));
 
     if (!result.ok()) {
       ACTS_ERROR("Propapation failed: " << result.error());