celeritas/ext/GeantUnits.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/ext/GeantUnits.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include "celeritas/Quantities.hh"
0011 #include "celeritas/UnitTypes.hh"
0012
0013 namespace celeritas
0014 {
0015 //---------------------------------------------------------------------------//
0016 // CONSTANTS
0017 //---------------------------------------------------------------------------//
0018 //! Value of a unit Celeritas field in the CLHEP unit system
0019 inline constexpr real_type clhep_field = 1
0020                                          / units::ClhepTraits::BField::value();
0021 //! Value of a unit Celeritas time in the CLHEP unit system
0022 inline constexpr real_type clhep_time = 1 / units::ClhepTraits::Time::value();
0023
0024 //---------------------------------------------------------------------------//
0025 /*!
0026  * Convert Celeritas energy quantities to Geant4.
0027  *
0028  * The unit value should always be CLHEP::MeV which is defined to be unity.
0029  */
0030 inline constexpr double
0031 convert_to_geant(units::MevEnergy const& energy, double units)
0032 {
0033     CELER_EXPECT(units == 1);
0034     return energy.value();
0035 }
0036
0037 //---------------------------------------------------------------------------//
0038 }  // namespace celeritas