PFRecHitProducerKernel.dev.cc

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#include <type_traits>

#include <alpaka/alpaka.hpp>

#include "HeterogeneousCore/AlpakaInterface/interface/config.h"
#include "HeterogeneousCore/AlpakaInterface/interface/workdivision.h"

#include "PFRecHitProducerKernel.h"

namespace ALPAKA_ACCELERATOR_NAMESPACE {
  using namespace particleFlowRecHitProducer;

  // Kernel to apply cuts to calorimeter hits and construct PFRecHits
  template <typename CAL>
  struct PFRecHitProducerKernelConstruct {
    template <typename TAcc, typename = std::enable_if_t<alpaka::isAccelerator<TAcc>>>
    ALPAKA_FN_ACC void operator()(const TAcc& acc,
                                  const typename CAL::ParameterType::ConstView params,
                                  const typename CAL::CaloRecHitSoATypeDevice::ConstView recHits,
                                  reco::PFRecHitDeviceCollection::View pfRecHits,
                                  uint32_t* __restrict__ denseId2pfRecHit,
                                  uint32_t* __restrict__ num_pfRecHits) const {
      // Strided loop over CaloRecHits
      for (int32_t i : cms::alpakatools::elements_with_stride(acc, recHits.metadata().size())) {
        // Check energy thresholds/quality cuts (specialised for HCAL/ECAL)
        if (!applyCuts(recHits[i], params))
          continue;

        // Use atomic operation to determine index of the PFRecHit to be constructed
        // The index needs to be unique and consequtive across all threads in all blocks.
        // This is achieved using the alpaka::hierarchy::Blocks argument.
        const uint32_t j = alpaka::atomicInc(acc, num_pfRecHits, 0xffffffff, alpaka::hierarchy::Blocks{});

        // Construct PFRecHit from CAL recHit (specialised for HCAL/ECAL)
        constructPFRecHit(pfRecHits[j], recHits[i]);

        // Fill denseId -> pfRecHit index map
        denseId2pfRecHit[CAL::detId2denseId(pfRecHits.detId(j))] = j;
      }
    }

    ALPAKA_FN_ACC static bool applyCuts(const typename CAL::CaloRecHitSoATypeDevice::ConstView::const_element rh,
                                        const typename CAL::ParameterType::ConstView params);

    ALPAKA_FN_ACC static void constructPFRecHit(
        reco::PFRecHitDeviceCollection::View::element pfrh,
        const typename CAL::CaloRecHitSoATypeDevice::ConstView::const_element rh);
  };

  template <>
  ALPAKA_FN_ACC bool PFRecHitProducerKernelConstruct<HCAL>::applyCuts(
      const typename HCAL::CaloRecHitSoATypeDevice::ConstView::const_element rh,
      const HCAL::ParameterType::ConstView params) {
    // Reject HCAL recHits below enery threshold
    float threshold = 9999.;
    const uint32_t detId = rh.detId();
    const uint32_t depth = HCAL::getDepth(detId);
    const uint32_t subdet = getSubdet(detId);
    if (subdet == HcalBarrel) {
      threshold = params.energyThresholds()[depth - 1];
    } else if (subdet == HcalEndcap) {
      threshold = params.energyThresholds()[depth - 1 + HCAL::kMaxDepthHB];
    } else {
      printf("Rechit with detId %u has invalid subdetector %u!\n", detId, subdet);
      return false;
    }
    return rh.energy() >= threshold;
  }

  template <>
  ALPAKA_FN_ACC bool PFRecHitProducerKernelConstruct<ECAL>::applyCuts(
      const ECAL::CaloRecHitSoATypeDevice::ConstView::const_element rh, const ECAL::ParameterType::ConstView params) {
    // Reject ECAL recHits below energy threshold
    if (rh.energy() < params.energyThresholds()[ECAL::detId2denseId(rh.detId())])
      return false;

    // Reject ECAL recHits of bad quality
    if ((ECAL::checkFlag(rh.flags(), ECAL::Flags::kOutOfTime) && rh.energy() > params.cleaningThreshold()) ||
        ECAL::checkFlag(rh.flags(), ECAL::Flags::kTowerRecovered) || ECAL::checkFlag(rh.flags(), ECAL::Flags::kWeird) ||
        ECAL::checkFlag(rh.flags(), ECAL::Flags::kDiWeird))
      return false;

    return true;
  }

  template <>
  ALPAKA_FN_ACC void PFRecHitProducerKernelConstruct<HCAL>::constructPFRecHit(
      reco::PFRecHitDeviceCollection::View::element pfrh,
      const HCAL::CaloRecHitSoATypeDevice::ConstView::const_element rh) {
    pfrh.detId() = rh.detId();
    pfrh.energy() = rh.energy();
    pfrh.time() = rh.time();
    pfrh.depth() = HCAL::getDepth(pfrh.detId());
    const uint32_t subdet = getSubdet(pfrh.detId());
    if (subdet == HcalBarrel)
      pfrh.layer() = PFLayer::HCAL_BARREL1;
    else if (subdet == HcalEndcap)
      pfrh.layer() = PFLayer::HCAL_ENDCAP;
    else
      pfrh.layer() = PFLayer::NONE;
  }

  template <>
  ALPAKA_FN_ACC void PFRecHitProducerKernelConstruct<ECAL>::constructPFRecHit(
      reco::PFRecHitDeviceCollection::View::element pfrh,
      const ECAL::CaloRecHitSoATypeDevice::ConstView::const_element rh) {
    pfrh.detId() = rh.detId();
    pfrh.energy() = rh.energy();
    pfrh.time() = rh.time();
    pfrh.depth() = 1;
    const uint32_t subdet = getSubdet(pfrh.detId());
    if (subdet == EcalBarrel)
      pfrh.layer() = PFLayer::ECAL_BARREL;
    else if (subdet == EcalEndcap)
      pfrh.layer() = PFLayer::ECAL_ENDCAP;
    else
      pfrh.layer() = PFLayer::NONE;
  }

  // Kernel to associate topology information of PFRecHits
  template <typename CAL>
  struct PFRecHitProducerKernelTopology {
    template <typename TAcc, typename = std::enable_if_t<alpaka::isAccelerator<TAcc>>>
    ALPAKA_FN_ACC void operator()(const TAcc& acc,
                                  const typename CAL::TopologyTypeDevice::ConstView topology,
                                  reco::PFRecHitDeviceCollection::View pfRecHits,
                                  const uint32_t* __restrict__ denseId2pfRecHit,
                                  uint32_t* __restrict__ num_pfRecHits) const {
      // First thread updates size field pfRecHits SoA
      if (const int32_t thread = alpaka::getIdx<alpaka::Grid, alpaka::Threads>(acc)[0u]; thread == 0)
        pfRecHits.size() = *num_pfRecHits;

      // Assign position information and associate neighbours
      for (int32_t i : cms::alpakatools::elements_with_stride(acc, *num_pfRecHits)) {
        const uint32_t denseId = CAL::detId2denseId(pfRecHits.detId(i));

        pfRecHits.x(i) = topology.positionX(denseId);
        pfRecHits.y(i) = topology.positionY(denseId);
        pfRecHits.z(i) = topology.positionZ(denseId);

        for (uint32_t n = 0; n < 8; n++) {
          pfRecHits.neighbours(i)(n) = -1;
          const uint32_t denseId_neighbour = topology.neighbours(denseId)(n);
          if (denseId_neighbour != 0xffffffff) {
            const uint32_t pfRecHit_neighbour = denseId2pfRecHit[denseId_neighbour];
            if (pfRecHit_neighbour != 0xffffffff)
              pfRecHits.neighbours(i)(n) = (int32_t)pfRecHit_neighbour;
          }
        }
      }
    }
  };

  template <typename CAL>
  PFRecHitProducerKernel<CAL>::PFRecHitProducerKernel(Queue& queue, const uint32_t num_recHits)
      : denseId2pfRecHit_(cms::alpakatools::make_device_buffer<uint32_t[]>(queue, CAL::kSize)),
        num_pfRecHits_(cms::alpakatools::make_device_buffer<uint32_t>(queue)),
        work_div_(cms::alpakatools::make_workdiv<Acc1D>(1, 1)) {
    alpaka::memset(queue, denseId2pfRecHit_, 0xff);  // Reset denseId -> pfRecHit index map
    alpaka::memset(queue, num_pfRecHits_, 0x00);     // Reset global pfRecHit counter

    const uint32_t items = 64;
    const uint32_t groups = cms::alpakatools::divide_up_by(num_recHits, items);
    work_div_ = cms::alpakatools::make_workdiv<Acc1D>(groups, items);
  }

  template <typename CAL>
  void PFRecHitProducerKernel<CAL>::processRecHits(Queue& queue,
                                                   const typename CAL::CaloRecHitSoATypeDevice& recHits,
                                                   const typename CAL::ParameterType& params,
                                                   reco::PFRecHitDeviceCollection& pfRecHits) {
    alpaka::exec<Acc1D>(queue,
                        work_div_,
                        PFRecHitProducerKernelConstruct<CAL>{},
                        params.view(),
                        recHits.view(),
                        pfRecHits.view(),
                        denseId2pfRecHit_.data(),
                        num_pfRecHits_.data());
  }

  template <typename CAL>
  void PFRecHitProducerKernel<CAL>::associateTopologyInfo(Queue& queue,
                                                          const typename CAL::TopologyTypeDevice& topology,
                                                          reco::PFRecHitDeviceCollection& pfRecHits) {
    alpaka::exec<Acc1D>(queue,
                        work_div_,
                        PFRecHitProducerKernelTopology<CAL>{},
                        topology.view(),
                        pfRecHits.view(),
                        denseId2pfRecHit_.data(),
                        num_pfRecHits_.data());
  }

  // Instantiate templates
  template class PFRecHitProducerKernel<HCAL>;
  template class PFRecHitProducerKernel<ECAL>;
}  // namespace ALPAKA_ACCELERATOR_NAMESPACE