optical/detail/CerenkovGeneratorExecutor.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2024 UT-Battelle, LLC, and other Celeritas developers.
0003 // See the top-level COPYRIGHT file for details.
0004 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0005 //---------------------------------------------------------------------------//
0006 //! \file celeritas/optical/detail/CerenkovGeneratorExecutor.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include "corecel/Macros.hh"
0011 #include "corecel/Types.hh"
0012 #include "corecel/math/Algorithms.hh"
0013 #include "celeritas/global/CoreTrackView.hh"
0014 #include "celeritas/optical/CerenkovGenerator.hh"
0015 #include "celeritas/optical/OffloadData.hh"
0016 #include "celeritas/track/CoreStateCounters.hh"
0017
0018 #include "OpticalUtils.hh"
0019
0020 namespace celeritas
0021 {
0022 namespace detail
0023 {
0024 //---------------------------------------------------------------------------//
0025 // LAUNCHER
0026 //---------------------------------------------------------------------------//
0027 /*!
0028  * Generate Cerenkov photons from optical distribution data.
0029  */
0030 struct CerenkovGeneratorExecutor
0031 {
0032     //// DATA ////
0033
0034     RefPtr<CoreStateData, MemSpace::native> state;
0035     NativeCRef<celeritas::optical::MaterialParamsData> const material;
0036     NativeCRef<celeritas::optical::CerenkovData> const cerenkov;
0037     NativeRef<OffloadStateData> const offload_state;
0038     RefPtr<celeritas::optical::CoreStateData, MemSpace::native> optical_state;
0039     OffloadBufferSize size;
0040     CoreStateCounters counters;
0041
0042     //// FUNCTIONS ////
0043
0044     // Generate optical track initializers
0045     inline CELER_FUNCTION void operator()(CoreTrackView const& track) const;
0046 };
0047
0048 //---------------------------------------------------------------------------//
0049 // INLINE DEFINITIONS
0050 //---------------------------------------------------------------------------//
0051 /*!
0052  * Generate Cerenkov photons from optical distribution data.
0053  */
0054 CELER_FUNCTION void
0055 CerenkovGeneratorExecutor::operator()(CoreTrackView const& track) const
0056 {
0057     CELER_EXPECT(state);
0058     CELER_EXPECT(cerenkov);
0059     CELER_EXPECT(material);
0060     CELER_EXPECT(offload_state);
0061     CELER_EXPECT(optical_state);
0062     CELER_EXPECT(size.cerenkov <= offload_state.cerenkov.size());
0063
0064     using DistId = ItemId<celeritas::optical::GeneratorDistributionData>;
0065     using InitId = ItemId<celeritas::optical::TrackInitializer>;
0066
0067     // Get the cumulative sum of the number of photons in the distributions.
0068     // Each bin gives the range of thread IDs that will generate from the
0069     // corresponding distribution
0070     auto offsets = offload_state.offsets[ItemRange<size_type>(
0071         ItemId<size_type>(0), ItemId<size_type>(size.cerenkov))];
0072
0073     // Get the total number of initializers to generate
0074     size_type total_work = offsets.back();
0075
0076     // Calculate the number of initializers for the thread to generate
0077     size_type local_work = LocalWorkCalculator<size_type>{
0078         total_work, state->size()}(track.thread_id().get());
0079
0080     auto rng = track.make_rng_engine();
0081
0082     for (auto i : range(local_work))
0083     {
0084         // Calculate the index in the initializer buffer (minus the offset)
0085         size_type idx = i * state->size() + track.thread_id().get();
0086
0087         // Find the distribution this thread will generate from
0088         size_type dist_idx = find_distribution_index(offsets, idx);
0089         CELER_ASSERT(dist_idx < size.cerenkov);
0090         auto const& dist = offload_state.cerenkov[DistId(dist_idx)];
0091         CELER_ASSERT(dist);
0092
0093         // Generate one primary from the distribution
0094         optical::MaterialView opt_mat{material, dist.material};
0095         celeritas::optical::CerenkovGenerator generate(opt_mat, cerenkov, dist);
0096         size_type init_idx = counters.num_initializers + idx;
0097         CELER_ASSERT(init_idx < optical_state->init.initializers.size());
0098         optical_state->init.initializers[InitId(init_idx)] = generate(rng);
0099     }
0100 }
0101
0102 //---------------------------------------------------------------------------//
0103 }  // namespace detail
0104 }  // namespace celeritas