include/accel/SimpleOffload.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2023-2024 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 accel/SimpleOffload.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 class G4Run;
0011 class G4Event;
0012 class G4Track;
0013
0014 namespace celeritas
0015 {
0016 class SharedParams;
0017 struct SetupOptions;
0018 class LocalTransporter;
0019
0020 //---------------------------------------------------------------------------//
0021 /*!
0022  * Compressed interface for running Celeritas in a multithread Geant4 app.
0023  *
0024  * This class *must* be a thread-local instance with references to data that
0025  * exceed the lifetime of the class: e.g. SharedParams can be a global
0026  * variable, and LocalTransporter can be a global variable with \c thread_local
0027  * storage duration.
0028  *
0029  * The \c CELER_DISABLE environment variable, if set and non-empty, will
0030  * disable offloading so that Celeritas will not be built nor kill tracks.
0031  *
0032  * The method names correspond to methods in Geant4 User Actions and *must* be
0033  * called from all threads, both worker and master.
0034  */
0035 class SimpleOffload
0036 {
0037   public:
0038     //! Construct with celeritas disabled
0039     SimpleOffload() = default;
0040
0041     // Construct from a reference to shared params and local data
0042     SimpleOffload(SetupOptions const* setup,
0043                   SharedParams* params,
0044                   LocalTransporter* local);
0045
0046     //! Lazy initialization of this class on a worker thread
0047     void Build(SetupOptions const* setup,
0048                SharedParams* params,
0049                LocalTransporter* local)
0050     {
0051         *this = {setup, params, local};
0052     }
0053
0054     //! Lazy initialization of this class on the master thread
0055     void BuildForMaster(SetupOptions const* setup, SharedParams* params)
0056     {
0057         *this = {setup, params, nullptr};
0058     }
0059
0060     // Initialize celeritas data from setup options
0061     void BeginOfRunAction(G4Run const* run);
0062
0063     // Send Celeritas the event ID
0064     void BeginOfEventAction(G4Event const* event);
0065
0066     // Send tracks to Celeritas if applicable and "StopAndKill" if so
0067     void PreUserTrackingAction(G4Track* track);
0068
0069     // Flush offloaded tracks from Celeritas
0070     void EndOfEventAction(G4Event const* event);
0071
0072     // Finalize
0073     void EndOfRunAction(G4Run const* run);
0074
0075     //! Whether offloading is enabled
0076     explicit operator bool() const { return setup_ != nullptr; }
0077
0078   private:
0079     SetupOptions const* setup_{nullptr};
0080     SharedParams* params_{nullptr};
0081     LocalTransporter* local_{nullptr};
0082 };
0083
0084 //---------------------------------------------------------------------------//
0085 }  // namespace celeritas