Start migration of propagation bits into Propagator

Author: mpuccio

Detectors/ITSMFT/common/tracking/CMakeLists.txt

@@ -36,7 +36,6 @@ o2_add_library(ITSMFTTracking
                        src/PropagatorBarrelOperations.cxx
                        src/PropagatorForwardOperations.cxx
                        src/MaterialPhysics.cxx
-                       src/FamilyMaterialOperations.cxx
                        src/IndexTableConfiguration.cxx
                        src/TraversalTopology.cxx
                        src/Tracker.cxx

Detectors/ITSMFT/common/tracking/include/ITSMFTTracking/MaterialPhysics.h

@@ -36,11 +36,10 @@ struct IntegratedMaterialBudget {
   float arealDensityGPerCm2; ///< crossed length*density, g/cm^2
 };
 
-// Detector-neutral, PID/absCharge-aware scalar material-physics kernel.
+// Scalar material-physics kernel for charged particles.
 // pid supplies the mass; absCharge supplies |q| for energy-loss and
-// scattering scale factors. It need not equal PID::getCharge(). For
-// absCharge == 0, validation still runs, then the operation succeeds with
-// unchanged momentum and zero material effects.
+// scattering scale factors. absCharge must be nonzero and need not equal
+// PID::getCharge().
 //
 // Validation precedence (first failure wins): invalid direction, negative
 // material, non-positive momentum, invalid PID, then a charged massless PID.

Detectors/ITSMFT/common/tracking/include/ITSMFTTracking/Propagator.h

@@ -71,6 +71,13 @@ class Propagator
                                      float bz, material::MaterialTraversalDirection direction,
                                      bool chi2GateEnabled, float maxChi2, float& chi2,
                                      bool shiftReferenceToMeasurement) noexcept;
+
+ private:
+  // Called only after propagation validates matching Cylinder/Disk kinds for
+  // the state and incidence reference. Select material formulas from state.kind.
+  static bool correctForMaterial(SurfaceTrackState& state, SurfaceTrackParameters& incidenceReference,
+                                 material::IntegratedMaterialBudget materialBudget,
+                                 material::MaterialTraversalDirection direction) noexcept;
 };
 
 } // namespace o2::itsmft::tracking

Detectors/ITSMFT/common/tracking/include/ITSMFTTracking/SurfaceTrackState.h

@@ -28,7 +28,8 @@ namespace o2::itsmft::tracking
 // Barrel:  (Y, Z, Snp, Tgl, Q2Pt), referenceCoordinate is local X, alpha is frame angle.
 // Forward: (X, Y, Phi, Tgl, Q2Pt), referenceCoordinate is global Z, alpha is unused (zero).
 
-// Fitted surface state. The field order keeps the device-facing representation
+// Fitted surface state for charged particles; valid tracks have absCharge > 0.
+// The field order keeps the device-facing representation
 // compact while the parameter-only linearization state remains independent.
 struct SurfaceTrackState {
   float parameters[5]{};
@@ -40,22 +41,14 @@ struct SurfaceTrackState {
   uint8_t absCharge{0};
   o2::track::PID pid{o2::track::PID::Pion};
 
+  GPUhdi() float getP() const noexcept
+  {
+    return absCharge * std::sqrt(1.f + parameters[3] * parameters[3]) / std::abs(parameters[4]);
+  }
+
   GPUhdi() constexpr bool hasRecognizedKind() const noexcept { return isRecognizedSurfaceKind(kind); }
 };
 
-static_assert(std::is_standard_layout_v<SurfaceTrackState>);
-static_assert(std::is_trivially_copyable_v<SurfaceTrackState>);
-static_assert(sizeof(SurfaceTrackState) == 92);
-static_assert(alignof(SurfaceTrackState) == 4);
-static_assert(offsetof(SurfaceTrackState, parameters) == 0);
-static_assert(offsetof(SurfaceTrackState, covariance) == 20);
-static_assert(offsetof(SurfaceTrackState, referenceCoordinate) == 80);
-static_assert(offsetof(SurfaceTrackState, alpha) == 84);
-static_assert(offsetof(SurfaceTrackState, kind) == 88);
-static_assert(offsetof(SurfaceTrackState, flags) == 89);
-static_assert(offsetof(SurfaceTrackState, absCharge) == 90);
-static_assert(offsetof(SurfaceTrackState, pid) == 91);
-
 // Covariance-free surface parameters used as the propagation linearization
 // point paired with one SurfaceTrackState.
 struct SurfaceTrackParameters {
@@ -76,15 +69,6 @@ struct SurfaceTrackParameters {
   GPUhdi() constexpr bool hasRecognizedKind() const noexcept { return isRecognizedSurfaceKind(kind); }
 };
 
-static_assert(std::is_standard_layout_v<SurfaceTrackParameters>);
-static_assert(std::is_trivially_copyable_v<SurfaceTrackParameters>);
-static_assert(sizeof(SurfaceTrackParameters) == 32);
-static_assert(alignof(SurfaceTrackParameters) == 4);
-static_assert(offsetof(SurfaceTrackParameters, parameters) == 0);
-static_assert(offsetof(SurfaceTrackParameters, referenceCoordinate) == 20);
-static_assert(offsetof(SurfaceTrackParameters, alpha) == 24);
-static_assert(offsetof(SurfaceTrackParameters, kind) == 28);
-
 GPUhdi() constexpr uint8_t packedCovarianceIndex(uint8_t row, uint8_t column) noexcept
 {
   return row >= column ? row * (row + 1) / 2 + column : column * (column + 1) / 2 + row;

Detectors/ITSMFT/common/tracking/include/ITSMFTTracking/detail/SurfaceStateOperations.h

@@ -12,7 +12,6 @@
 #ifndef ALICEO2_ITSMFT_TRACKING_DETAIL_SURFACESTATEOPERATIONS_H_
 #define ALICEO2_ITSMFT_TRACKING_DETAIL_SURFACESTATEOPERATIONS_H_
 
-#include "ITSMFTTracking/MaterialPhysics.h"
 #include "ITSMFTTracking/SurfaceTrackState.h"
 #include "ITSMFTTracking/SurfaceMeasurement.h"
 
@@ -27,11 +26,6 @@ bool rotate(SurfaceTrackState& state, float targetAlpha) noexcept;
 bool propagate(SurfaceTrackState& state, float targetX, float bz) noexcept;
 bool predictedChi2(const SurfaceTrackState& state, const SurfaceMeasurement& measurement, float& chi2) noexcept;
 bool update(SurfaceTrackState& state, const SurfaceMeasurement& measurement, float& chi2) noexcept;
-bool correctForMaterial(SurfaceTrackState& state, material::IntegratedMaterialBudget materialBudget,
-                        material::MaterialTraversalDirection direction) noexcept;
-bool correctForMaterial(SurfaceTrackState& state, SurfaceTrackParameters& linRef,
-                        material::IntegratedMaterialBudget materialBudget,
-                        material::MaterialTraversalDirection direction) noexcept;
 bool stateChi2(const SurfaceTrackState& reference, const SurfaceTrackState& candidate, float& chi2) noexcept;
 
 #ifndef GPUCA_GPUCODE
@@ -48,17 +42,6 @@ bool propagate(SurfaceTrackState& state, SurfaceTrackParameters& linRef,
                float targetZ, float bz) noexcept;
 bool predictedChi2(const SurfaceTrackState& state, const SurfaceMeasurement& measurement, float& chi2) noexcept;
 bool update(SurfaceTrackState& state, const SurfaceMeasurement& measurement, float& chi2) noexcept;
-constexpr float highlandTheta2(float inverseMomentum, float xOverX0) noexcept
-{
-  const float theta = 0.0136f * inverseMomentum;
-  return theta * theta * xOverX0;
-}
-bool correctForMaterial(SurfaceTrackState& state, float xOverX0) noexcept;
-bool correctForMaterial(SurfaceTrackState& state, material::IntegratedMaterialBudget materialBudget,
-                        material::MaterialTraversalDirection direction) noexcept;
-bool correctForMaterial(SurfaceTrackState& state, SurfaceTrackParameters& linRef,
-                        material::IntegratedMaterialBudget materialBudget,
-                        material::MaterialTraversalDirection direction) noexcept;
 bool stateChi2(const SurfaceTrackState& reference, const SurfaceTrackState& candidate, float& chi2) noexcept;
 
 #ifndef GPUCA_GPUCODE