TrackingRecHitsDevice.h

#ifndef DataFormats_TrackingRecHitSoA_interface_TrackingRecHitSoADevice_h
#define DataFormats_TrackingRecHitSoA_interface_TrackingRecHitSoADevice_h

#include <cstdint>

#include <alpaka/alpaka.hpp>

#include "DataFormats/Common/interface/Uninitialized.h"
#include "DataFormats/Portable/interface/PortableDeviceCollection.h"
#include "DataFormats/TrackingRecHitSoA/interface/TrackingRecHitsHost.h"
#include "DataFormats/TrackingRecHitSoA/interface/TrackingRecHitsSoA.h"
#include "Geometry/CommonTopologies/interface/SimpleSeedingLayersTopology.h"

template <typename TrackerTraits, typename TDev>
class TrackingRecHitDevice : public PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev> {
public:
  using hitSoA = TrackingRecHitSoA<TrackerTraits>;

  // Need to decorate the class with the inherited portable accessors being now a template
  using PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev>::view;
  using PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev>::const_view;
  using PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev>::buffer;

  TrackingRecHitDevice(edm::Uninitialized)
      : PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev>{edm::kUninitialized} {}

  // Constructor which specifies the SoA size, number of BPIX1 hits, and the modules entry points
  template <typename TQueue>
  explicit TrackingRecHitDevice(TQueue queue, uint32_t nHits, int32_t offsetBPIX2, uint32_t const* hitsModuleStart)
      : PortableDeviceCollection<TrackingRecHitLayout<TrackerTraits>, TDev>(nHits, queue), offsetBPIX2_{offsetBPIX2} {
    auto start_h = cms::alpakatools::make_device_view(queue, hitsModuleStart, TrackerTraits::numberOfModules + 1);
    auto start_d =
        cms::alpakatools::make_device_view(queue, view().hitsModuleStart().data(), TrackerTraits::numberOfModules + 1);
    alpaka::memcpy(queue, start_d, start_h);

    auto off_h = cms::alpakatools::make_host_view(offsetBPIX2_);
    auto off_d = cms::alpakatools::make_device_view(queue, view().offsetBPIX2());
    alpaka::memcpy(queue, off_d, off_h);
  }

  uint32_t nHits() const { return view().metadata().size(); }

  int32_t offsetBPIX2() const { return offsetBPIX2_; }

  uint32_t const* hitsModuleStart() const { return view().hitsModuleStart().data(); }

  // asynchronously update the information cached within the class itself from the information on the device
  template <typename TQueue>
  void updateFromDevice(TQueue queue) {
    auto off_h = cms::alpakatools::make_host_view(offsetBPIX2_);
    auto off_d = cms::alpakatools::make_device_view(queue, view().offsetBPIX2());
    alpaka::memcpy(queue, off_h, off_d);
  }

private:
  // offsetBPIX2 is used on host functions so is useful to have it also stored in the class and not only in the layout
  int32_t offsetBPIX2_ = 0;
};

#endif  // DataFormats_RecHits_interface_TrackingRecHitSoADevice_h