ITS: make MaxIter a constant

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Author: f3sch

Detectors/ITSMFT/ITS/tracking/GPU/cuda/TimeFrameGPU.cu

@@ -627,8 +627,7 @@ constexpr auto makeIterTags(std::index_sequence<I...>)
 {
   return std::array<uint64_t, sizeof...(I)>{makeIterTag<I>()...};
 }
-// FIXME: we have to be careful that the MaxIter does not diverge from the 4 here!
-constexpr auto kIterTags = makeIterTags(std::make_index_sequence<4>{});
+constexpr auto kIterTags = makeIterTags(std::make_index_sequence<constants::MaxIter>{});
 } // namespace detail
 
 template <int NLayers>

Detectors/ITSMFT/ITS/tracking/include/ITStracking/Constants.h

@@ -31,12 +31,13 @@ constexpr float GB = MB * KB;
 constexpr bool DoTimeBenchmarks = true;
 constexpr bool SaveTimeBenchmarks = false;
 
-GPUconstexpr() float Tolerance{1e-12}; // numerical tolerance
-GPUconstexpr() int ClustersPerCell{3};
-GPUconstexpr() int UnusedIndex{-1};
-GPUconstexpr() float Resolution{0.0005f};
+GPUconstexpr() float Tolerance = 1e-12; // numerical tolerance
+GPUconstexpr() int ClustersPerCell = 3;
+GPUconstexpr() int UnusedIndex = -1;
+GPUconstexpr() float Resolution = 0.0005f;
 GPUconstexpr() float Radl = 9.36f; // Radiation length of Si [cm]
 GPUconstexpr() float Rho = 2.33f;  // Density of Si [g/cm^3]
+GPUconstexpr() int MaxIter = 4;    // Max. supported iterations
 
 namespace helpers
 {

Detectors/ITSMFT/ITS/tracking/include/ITStracking/TrackingConfigParam.h

@@ -15,6 +15,7 @@
 #include <limits>
 #include "CommonUtils/ConfigurableParam.h"
 #include "CommonUtils/ConfigurableParamHelper.h"
+#include "ITStracking/Constants.h"
 
 namespace o2::its
 {
@@ -36,9 +37,9 @@ struct VertexerParamConfig : public o2::conf::ConfigurableParamHelper<VertexerPa
   float duplicateZCut = 0.7985643f;
   float finalSelectionZCut = 0.2932624f;
   float duplicateDistance2Cut = 0.0223001f;
-  float tanLambdaCut = 0.002f;        // tanLambda = deltaZ/deltaR
+  float tanLambdaCut = 0.002f; // tanLambda = deltaZ/deltaR
   float nSigmaCut = 0.0479011f;
-  float maxZPositionAllowed = 25.f;   // 4x sZ of the beam
+  float maxZPositionAllowed = 25.f; // 4x sZ of the beam
 
   // Artefacts selections
   int clusterContributorsCut = 3; // minimum number of contributors for an accepted final vertex
@@ -62,18 +63,17 @@ struct VertexerParamConfig : public o2::conf::ConfigurableParamHelper<VertexerPa
 };
 
 struct TrackerParamConfig : public o2::conf::ConfigurableParamHelper<TrackerParamConfig> {
-  // Use TGeo for mat. budget
-  static const int MaxIter = 4;
   static const int MinTrackLength = 4;
   static const int MaxTrackLength = 7;
-  bool useMatCorrTGeo = false;                                              // use full geometry to corect for material budget accounting in the fits. Default is to use the material budget LUT.
-  bool useFastMaterial = false;                                             // use faster material approximation for material budget accounting in the fits.
-  int addTimeError[7] = {0};                                                // configure the width of the window in BC to be considered for the tracking.
-  int minTrackLgtIter[MaxIter] = {};                                        // minimum track length at each iteration, used only if >0, otherwise use code defaults
-  uint8_t startLayerMask[MaxIter] = {};                                     // mask of start layer for this iteration (if >0)
-  float minPtIterLgt[MaxIter * (MaxTrackLength - MinTrackLength + 1)] = {}; // min.pT for given track length at this iteration, used only if >0, otherwise use code defaults
-  float sysErrY2[7] = {0};                                                  // systematic error^2 in Y per layer
-  float sysErrZ2[7] = {0};                                                  // systematic error^2 in Z per layer
+
+  bool useMatCorrTGeo = false;                                                         // use full geometry to corect for material budget accounting in the fits. Default is to use the material budget LUT.
+  bool useFastMaterial = false;                                                        // use faster material approximation for material budget accounting in the fits.
+  int addTimeError[7] = {0};                                                           // configure the width of the window in BC to be considered for the tracking.
+  int minTrackLgtIter[constants::MaxIter] = {};                                        // minimum track length at each iteration, used only if >0, otherwise use code defaults
+  uint8_t startLayerMask[constants::MaxIter] = {};                                     // mask of start layer for this iteration (if >0)
+  float minPtIterLgt[constants::MaxIter * (MaxTrackLength - MinTrackLength + 1)] = {}; // min.pT for given track length at this iteration, used only if >0, otherwise use code defaults
+  float sysErrY2[7] = {0};                                                             // systematic error^2 in Y per layer
+  float sysErrZ2[7] = {0};                                                             // systematic error^2 in Z per layer
   float maxChi2ClusterAttachment = -1.f;
   float maxChi2NDF = -1.f;
   float nSigmaCut = -1.f;
@@ -89,7 +89,7 @@ struct TrackerParamConfig : public o2::conf::ConfigurableParamHelper<TrackerPara
   bool overrideBeamEstimation = false;     // use beam position from meanVertex CCDB object
   int trackingMode = -1;                   // -1: unset, 0=sync, 1=async, 2=cosmics used by gpuwf only
   bool doUPCIteration = false;             // Perform an additional iteration for UPC events on tagged vertices. You want to combine this config with VertexerParamConfig.nIterations=2
-  int nIterations = MaxIter;               // overwrite the number of iterations
+  int nIterations = constants::MaxIter;    // overwrite the number of iterations
   int reseedIfShorter = 6;                 // for the final refit reseed the track with circle if they are shorter than this value
   bool shiftRefToCluster{true};            // TrackFit: after update shift the linearization reference to cluster
   bool repeatRefitOut{false};              // repeat outward refit using inward refit as a seed

Detectors/ITSMFT/ITS/tracking/src/Configuration.cxx

@@ -141,7 +141,7 @@ std::vector<TrackingParameters> TrackingMode::getTrackingParameters(TrackingMode
       param.ZBins = 64;
       param.PhiBins = 32;
       // check if something was overridden via configurable params
-      if (ip < tc.MaxIter) {
+      if (ip < constants::MaxIter) {
         if (tc.startLayerMask[ip] > 0) {
           trackParams[2].StartLayerMask = tc.startLayerMask[ip];
         }