celeritas/phys/PrimaryGeneratorOptions.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2022-2024 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/phys/PrimaryGeneratorOptions.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include <algorithm>
0011 #include <functional>
0012 #include <random>
0013
0014 #include "corecel/io/StringEnumMapper.hh"
0015 #include "geocel/Types.hh"
0016
0017 #include "PDGNumber.hh"
0018
0019 namespace celeritas
0020 {
0021 //---------------------------------------------------------------------------//
0022 //! Distribution selection for sampling quantities in a \c PrimaryGenerator
0023 enum class DistributionSelection
0024 {
0025     delta,
0026     isotropic,
0027     box,
0028     size_
0029 };
0030
0031 //---------------------------------------------------------------------------//
0032 /*!
0033  * Distribution type and parameters.
0034  */
0035 struct DistributionOptions
0036 {
0037     DistributionSelection distribution{DistributionSelection::size_};
0038     std::vector<real_type> params;
0039
0040     //! Whether the options are valid
0041     explicit operator bool() const
0042     {
0043         return distribution != DistributionSelection::size_;
0044     }
0045 };
0046
0047 //---------------------------------------------------------------------------//
0048 /*!
0049  * Primary generator options.
0050  *
0051  * TODO: distributions should be std::variant (see ORANGE input)
0052  *
0053  * - \c seed: RNG seed
0054  * - \c pdg: PDG numbers of the primaries. An equal number of primaries of each
0055  *   type will be generated
0056  * - \c num_events: total number of events to generate
0057  * - \c primaries_per_event: number of primaries to generate in each event
0058  * - \c energy: energy distribution type and parameters
0059  * - \c position: spatial distribution type and parameters
0060  * - \c direction: angular distribution type and parameters
0061  */
0062 struct PrimaryGeneratorOptions
0063 {
0064     unsigned int seed{};
0065     std::vector<PDGNumber> pdg;
0066     size_type num_events{};
0067     size_type primaries_per_event{};
0068     DistributionOptions energy;
0069     DistributionOptions position;
0070     DistributionOptions direction;
0071
0072     //! Whether the options are valid
0073     explicit operator bool() const
0074     {
0075         return !pdg.empty()
0076                && std::all_of(pdg.begin(),
0077                               pdg.end(),
0078                               [](PDGNumber p) { return static_cast<bool>(p); })
0079                && num_events > 0 && primaries_per_event > 0 && energy
0080                && position && direction;
0081     }
0082 };
0083
0084 // TODO: move to PrimaryGenerator.hh
0085
0086 using PrimaryGeneratorEngine = std::mt19937;
0087
0088 //---------------------------------------------------------------------------//
0089 // FREE FUNCTIONS
0090 //---------------------------------------------------------------------------//
0091
0092 // Get a distribution name
0093 char const* to_cstring(DistributionSelection value);
0094
0095 // TODO: move these to PrimaryGenerator.hh
0096 //! \cond
0097
0098 // Return a distribution for sampling the energy
0099 std::function<real_type(PrimaryGeneratorEngine&)>
0100 make_energy_sampler(DistributionOptions options);
0101
0102 // Return a distribution for sampling the position
0103 std::function<Real3(PrimaryGeneratorEngine&)>
0104 make_position_sampler(DistributionOptions options);
0105
0106 // Return a distribution for sampling the direction
0107 std::function<Real3(PrimaryGeneratorEngine&)>
0108 make_direction_sampler(DistributionOptions options);
0109
0110 //! \endcond
0111 //---------------------------------------------------------------------------//
0112 }  // namespace celeritas