celeritas/optical/Interaction.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/optical/Interaction.hh
0006 //---------------------------------------------------------------------------//
0007 #pragma once
0008
0009 #include "corecel/Macros.hh"
0010 #include "corecel/cont/Span.hh"
0011 #include "geocel/Types.hh"
0012
0013 #include "TrackInitializer.hh"
0014
0015 namespace celeritas
0016 {
0017 namespace optical
0018 {
0019 //---------------------------------------------------------------------------//
0020 /*!
0021  * The result of a discrete optical interaction.
0022  *
0023  * All optical interactions are discrete. The wavelength of a photon is only
0024  * changed through absorption re-emission processes.
0025  */
0026 struct Interaction
0027 {
0028     //! Interaction result category
0029     enum class Action
0030     {
0031         scattered,  //!< Still alive, state has changed
0032         absorbed,  //!< Absorbed by the material
0033         unchanged,  //!< No state change, no secondaries
0034         failed,  //!< Ran out of memory during sampling
0035     };
0036
0037     Real3 direction;  //!< Post-interaction direction
0038     Real3 polarization;  //!< Post-interaction polarization
0039     Span<TrackInitializer> secondaries;  //!< Emitted secondaries
0040     Action action{Action::scattered};  //!< Flags for interaction result
0041
0042     //! Return an interaction respresenting an absorbed process
0043     static inline CELER_FUNCTION Interaction from_absorption();
0044
0045     //! Return an interaction with no change in the track state
0046     static inline CELER_FUNCTION Interaction from_unchanged();
0047
0048     // Return an interaction representing a recoverable error
0049     static inline CELER_FUNCTION Interaction from_failure();
0050
0051     //! Whether the state changed but did not fail
0052     CELER_FUNCTION bool changed() const
0053     {
0054         return static_cast<int>(action) < static_cast<int>(Action::unchanged);
0055     }
0056 };
0057
0058 //---------------------------------------------------------------------------//
0059 // INLINE DEFINITIONS
0060 //---------------------------------------------------------------------------//
0061 /*!
0062  * Construct an interaction for an absorbed optical photon.
0063  */
0064 CELER_FUNCTION Interaction Interaction::from_absorption()
0065 {
0066     Interaction result;
0067     result.action = Action::absorbed;
0068     return result;
0069 }
0070
0071 //---------------------------------------------------------------------------//
0072 /*!
0073  * Construct an interaction for edge cases where this is no state change.
0074  */
0075 CELER_FUNCTION Interaction Interaction::from_unchanged()
0076 {
0077     Interaction result;
0078     result.action = Action::unchanged;
0079     return result;
0080 }
0081
0082 //---------------------------------------------------------------------------//
0083 /*!
0084  * Indicate a failure to allocate memory for secondaries.
0085  */
0086 CELER_FUNCTION Interaction Interaction::from_failure()
0087 {
0088     Interaction result;
0089     result.action = Action::failed;
0090     return result;
0091 }
0092
0093 //---------------------------------------------------------------------------//
0094 }  // namespace optical
0095 }  // namespace celeritas