Add gpuSpan

Author: mconcas

Detectors/ITSMFT/ITS/tracking/GPU/ITStrackingGPU/Utils.h

@@ -29,6 +29,24 @@ struct gpuPair {
   T2 second;
 };
 
+template <typename T>
+struct gpuSpan {
+  GPUd() gpuSpan() : _data(nullptr), _size(0) {}
+  GPUd() gpuSpan(T* data, size_t size) : _data(data), _size(size) {}
+  GPUd() gpuSpan(const T* data, size_t size) : _data(data), _size(size) {}
+  GPUd() T& operator[](size_t idx) const { return _data[idx]; }
+  GPUd() size_t size() const { return _size; }
+  GPUd() bool empty() const { return _size == 0; }
+  GPUd() T& front() const { return _data[0]; }
+  GPUd() T& back() const { return _data[_size - 1]; }
+  GPUd() T* begin() const { return _data; }
+  GPUd() T* end() const { return _data + _size; }
+
+ protected:
+  const T* _data;
+  size_t _size;
+};
+
 namespace gpu
 {
 

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

@@ -32,6 +32,7 @@
 #include "ITStracking/IndexTableUtils.h"
 #include "ITStracking/MathUtils.h"
 #include "DataFormatsITS/TrackITS.h"
+#include "ReconstructionDataFormats/Vertex.h"
 
 #include "ITStrackingGPU/TrackerTraitsGPU.h"
 #include "ITStrackingGPU/TrackingKernels.h"
@@ -70,10 +71,9 @@ inline void gpuAssert(cudaError_t code, const char* file, int line, bool abort =
 }
 
 namespace o2::its
-
 {
 using namespace constants::its2;
-
+using Vertex = o2::dataformats::Vertex<o2::dataformats::TimeStamp<int>>;
 namespace gpu
 {
 GPUd() bool fitTrack(TrackITSExt& track,
@@ -196,9 +196,17 @@ struct is_valid_pair {
   }
 };
 
-GPUd() void getPrimaryVertices(const int rof,
-                               const uint8_t* mask,
-                               const Vertex* vertices);
+GPUd() gpuSpan<Vertex> getPrimaryVertices(const int rof,
+                                          const int* roframesPV,
+                                          const int nRof,
+                                          const uint8_t* mask,
+                                          const Vertex* vertices)
+{
+  const int start = roframesPV[rof];
+  const int stop_idx = rof >= nRof - 1 ? nRof : rof + 1;
+  size_t delta = mask[rof] ? roframesPV[stop_idx] - start : 0; // return empty span if Rof is excluded
+  return gpuSpan<Vertex>(&vertices[start], delta);
+};
 
 template <int nLayers>
 GPUg() void fitTrackSeedsKernel(