refactor: Align overstep limit (#2441)

Overstep limits are defined differently in our 3 steppers. This PR aligns them to the convention in the `EigenStepper`. The `StraightLineStepper` returned the wrong sign which might have affected Fatras simulation for neutral particles. Pulled out of #2336
acts-project · Sep 14, 2023 · f581704 · f581704
1 parent e8600a4
commit f581704
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Showing 8 changed files with 9 additions and 7 deletions.
diff --git a/CI/physmon/reference/performance_ambi_ttbar.root b/CI/physmon/reference/performance_ambi_ttbar.root
diff --git a/CI/physmon/reference/performance_amvf_gridseeder_ttbar_hist.root b/CI/physmon/reference/performance_amvf_gridseeder_ttbar_hist.root
diff --git a/CI/physmon/reference/performance_amvf_ttbar_hist.root b/CI/physmon/reference/performance_amvf_ttbar_hist.root
diff --git a/CI/physmon/reference/performance_ckf_ttbar.root b/CI/physmon/reference/performance_ckf_ttbar.root
diff --git a/CI/physmon/reference/performance_gsf.root b/CI/physmon/reference/performance_gsf.root
diff --git a/CI/physmon/reference/performance_seeding_ttbar.root b/CI/physmon/reference/performance_seeding_ttbar.root
diff --git a/Core/include/Acts/Propagator/AtlasStepper.hpp b/Core/include/Acts/Propagator/AtlasStepper.hpp
@@ -364,7 +364,9 @@ class AtlasStepper {
   }
 
   /// Overstep limit
-  double overstepLimit(const State& /*state*/) const { return m_overstepLimit; }
+  double overstepLimit(const State& /*state*/) const {
+    return -m_overstepLimit;
+  }
 
   /// Time access
   double time(const State& state) const { return state.pVector[3]; }
@@ -1416,7 +1418,7 @@ class AtlasStepper {
   std::shared_ptr<const MagneticFieldProvider> m_bField;
 
   /// Overstep limit: could/should be dynamic
-  double m_overstepLimit = -100 * UnitConstants::um;
+  double m_overstepLimit = 100 * UnitConstants::um;
 };
 
 }  // namespace Acts
diff --git a/Core/include/Acts/Propagator/StraightLineStepper.hpp b/Core/include/Acts/Propagator/StraightLineStepper.hpp
@@ -218,11 +218,8 @@ class StraightLineStepper {
   double time(const State& state) const { return state.pars[eFreeTime]; }
 
   /// Overstep limit
-  ///
-  /// @param state The stepping state (thread-local cache)
-  double overstepLimit(const State& state) const {
-    (void)state;
-    return s_onSurfaceTolerance;
+  double overstepLimit(const State& /*state*/) const {
+    return -m_overstepLimit;
   }
 
   /// Update surface status
@@ -418,6 +415,9 @@ class StraightLineStepper {
     // return h
     return h;
   }
+
+ private:
+  double m_overstepLimit = s_onSurfaceTolerance;
 };
 
 }  // namespace Acts