alongstep/detail/MeanELoss.hh

0001 //------------------------------- -*- C++ -*- -------------------------------//
0002 // Copyright Celeritas contributors: see top-level COPYRIGHT file for details
0003 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0004 //---------------------------------------------------------------------------//
0005 //! \file celeritas/alongstep/detail/MeanELoss.hh
0006 //---------------------------------------------------------------------------//
0007 #pragma once
0008
0009 #include "corecel/Assert.hh"
0010 #include "celeritas/global/CoreTrackView.hh"
0011 #include "celeritas/phys/PhysicsStepUtils.hh"
0012
0013 namespace celeritas
0014 {
0015 namespace detail
0016 {
0017 //---------------------------------------------------------------------------//
0018 /*!
0019  * Calculate energy loss (*without* fluctuations) to a track.
0020  */
0021 class MeanELoss
0022 {
0023   public:
0024     //!@{
0025     //! \name Type aliases
0026     using Energy = ParticleTrackView::Energy;
0027     //!@}
0028
0029   public:
0030     // Whether energy loss is used for this track
0031     inline CELER_FUNCTION bool is_applicable(CoreTrackView const&) const;
0032
0033     // Apply to the track
0034     inline CELER_FUNCTION Energy calc_eloss(CoreTrackView const& track,
0035                                             real_type step,
0036                                             bool apply_cut);
0037
0038     //! Particle will slow down to zero only if range limited
0039     static CELER_CONSTEXPR_FUNCTION bool imprecise_range() { return false; }
0040 };
0041
0042 //---------------------------------------------------------------------------//
0043 // INLINE DEFINITIONS
0044 //---------------------------------------------------------------------------//
0045 /*!
0046  * Whether energy loss is used for this track.
0047  */
0048 CELER_FUNCTION bool MeanELoss::is_applicable(CoreTrackView const& track) const
0049 {
0050     // The track can be marked as `errored` *within* the along-step kernel,
0051     // during propagation
0052     if (track.sim().status() == TrackStatus::errored)
0053         return false;
0054
0055     // Energy loss grid ID is 'false'
0056     return static_cast<bool>(track.physics().energy_loss_grid());
0057 }
0058
0059 //---------------------------------------------------------------------------//
0060 /*!
0061  * Apply energy loss to the given track.
0062  */
0063 CELER_FUNCTION auto MeanELoss::calc_eloss(CoreTrackView const& track,
0064                                           real_type step,
0065                                           bool apply_cut) -> Energy
0066 {
0067     CELER_EXPECT(step > 0);
0068
0069     auto particle = track.particle();
0070     auto phys = track.physics();
0071
0072     if (apply_cut && particle.energy() < phys.particle_scalars().lowest_energy)
0073     {
0074         // Deposit all energy when we start below the tracking cut
0075         return particle.energy();
0076     }
0077
0078     // Calculate the mean energy loss
0079     Energy eloss = calc_mean_energy_loss(particle, phys, step);
0080
0081     if (apply_cut
0082         && (particle.energy() - eloss <= phys.particle_scalars().lowest_energy))
0083     {
0084         // Deposit all energy when we end below the tracking cut
0085         return particle.energy();
0086     }
0087
0088     CELER_ENSURE(eloss <= particle.energy());
0089     CELER_ENSURE(eloss != particle.energy()
0090                  || track.sim().post_step_action()
0091                         == phys.scalars().range_action());
0092     return eloss;
0093 }
0094
0095 //---------------------------------------------------------------------------//
0096 }  // namespace detail
0097 }  // namespace celeritas