From c34b62043e8178e5d72ef323323155f83239d2af Mon Sep 17 00:00:00 2001
From: Moritz Kiehn <msmk@cern.ch>
Date: Fri, 13 Mar 2020 18:14:02 +0100
Subject: [PATCH] Utilities: update bound parameters index enum
---
.../detail/DefaultParameterDefinitions.hpp | 56 +++++++++++++++----
1 file changed, 44 insertions(+), 12 deletions(-)
diff --git a/Core/include/Acts/Utilities/detail/DefaultParameterDefinitions.hpp b/Core/include/Acts/Utilities/detail/DefaultParameterDefinitions.hpp
index e371c348c..5d6b5337d 100644
--- a/Core/include/Acts/Utilities/detail/DefaultParameterDefinitions.hpp
+++ b/Core/include/Acts/Utilities/detail/DefaultParameterDefinitions.hpp
@@ -15,23 +15,54 @@
#include "Acts/Utilities/ParameterTypes.hpp"
namespace Acts {
-enum ParDef : unsigned int {
- eLOC_0 = 0, ///< first coordinate in local surface frame
- eLOC_1 = 1, ///< second coordinate in local surface frame
+
+/// Components of a bound track parameters vector.
+///
+/// To be used to access components by named indices instead of just numbers.
+/// This must be a regular `enum` and not a scoped `enum class` to allow
+/// implicit conversion to an integer. The enum value are thus visible directly
+/// in `namespace Acts` and are prefixed to avoid naming collisions.
+enum BoundParametersIndices : unsigned int {
+ // Local position on the reference surface.
+ // This is intentionally named different from the position components in
+ // the other data vectors, to clarify that this is defined on a surface
+ // while the others are defined in free space.
+ eBoundLoc0 = 0,
+ eBoundLoc1 = 1,
+ // Direction angles
+ eBoundPhi = 2,
+ eBoundTheta = 3,
+ // Global inverse-momentum-like parameter, i.e. q/p or 1/p
+ // The naming is inconsistent for the case of neutral track parameters where
+ // the value is interpreted as 1/p not as q/p. This is intentional to avoid
+ // having multiple aliases for the same element and for lack of an acceptable
+ // common name.
+ eBoundQOverP = 4,
+ eBoundTime = 5,
+ // Last uninitialized value contains the total number of components
+ eBoundParametersSize,
+ // The following aliases without prefix exist for historical reasons
+ // Generic spatial coordinates on the local surface
+ eLOC_0 = eBoundLoc0,
+ eLOC_1 = eBoundLoc1,
+ // Spatial coordinates on a disk in polar coordinates
eLOC_R = eLOC_0,
eLOC_PHI = eLOC_1,
- eLOC_RPHI = eLOC_0,
- eLOC_Z = eLOC_1,
+ // Spatial coordinates on a disk in Cartesian coordinates
eLOC_X = eLOC_0,
eLOC_Y = eLOC_1,
+ // Spatial coordinates on a cylinder
+ eLOC_RPHI = eLOC_0,
+ eLOC_Z = eLOC_1,
+ // Closest approach coordinates on a virtual perigee surface
eLOC_D0 = eLOC_0,
eLOC_Z0 = eLOC_1,
- ePHI = 2, ///< phi direction of momentum in global frame
- eTHETA = 3, ///< theta direction of momentum in global frame
- eQOP = 4, ///< charge/momentum for charged tracks, for neutral tracks it is
- /// 1/momentum
- eT = 5, /// < The time of the particle
- BoundParsDim /// < The local dimensions
+ // Direction angles
+ ePHI = eBoundPhi,
+ eTHETA = eBoundTheta,
+ eQOP = eBoundQOverP,
+ eT = eBoundTime,
+ BoundParsDim = eBoundParametersSize,
};
/// Components of a free track parameters vector.
@@ -89,7 +120,8 @@ enum SpacePointIndices : unsigned int {
SpacePointDim = eSpacePointSize,
};
-using ParID_t = ParDef;
+using ParDef = BoundParametersIndices;
+using ParID_t = BoundParametersIndices;
using ParValue_t = double;
///
--
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