geocel/g4/Convert.geant.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 geocel/g4/Convert.geant.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include <G4ThreeVector.hh>
0011
0012 #include "corecel/Types.hh"
0013 #include "corecel/cont/Array.hh"
0014 #include "geocel/Types.hh"
0015 #include "geocel/detail/LengthUnits.hh"
0016
0017 namespace celeritas
0018 {
0019 //---------------------------------------------------------------------------//
0020 // CONSTANTS
0021 //---------------------------------------------------------------------------//
0022 //! Value of a unit Celeritas length in the CLHEP unit system
0023 inline constexpr real_type clhep_length = 1 / lengthunits::millimeter;
0024
0025 //---------------------------------------------------------------------------//
0026 // FREE FUNCTIONS
0027 //---------------------------------------------------------------------------//
0028 /*!
0029  * Convert a value from Geant4/CLHEP to Celeritas native units.
0030  */
0031 template<class T>
0032 constexpr inline T convert_from_geant(T const& val, T units)
0033 {
0034     return val / units;
0035 }
0036
0037 //---------------------------------------------------------------------------//
0038 /*!
0039  * Convert a value from Geant4 with CLHEP units.
0040  */
0041 constexpr inline double convert_from_geant(double val, double units)
0042 {
0043     return val / units;
0044 }
0045
0046 //---------------------------------------------------------------------------//
0047 /*!
0048  * Convert a 3-vector from Geant4/CLHEP to Celeritas native units.
0049  */
0050 inline Real3 convert_from_geant(G4ThreeVector const& vec, double units)
0051 {
0052     return {static_cast<real_type>(vec[0] / units),
0053             static_cast<real_type>(vec[1] / units),
0054             static_cast<real_type>(vec[2] / units)};
0055 }
0056
0057 //---------------------------------------------------------------------------//
0058 /*!
0059  * Convert a C array from Geant4/CLHEP to Celeritas native units.
0060  */
0061 inline Real3 convert_from_geant(double const vec[3], double units)
0062 {
0063     return {static_cast<real_type>(vec[0] / units),
0064             static_cast<real_type>(vec[1] / units),
0065             static_cast<real_type>(vec[2] / units)};
0066 }
0067
0068 //---------------------------------------------------------------------------//
0069 /*!
0070  * Convert a native Celeritas quantity to a Geant4 value with CLHEP units.
0071  */
0072 template<class T>
0073 constexpr inline T convert_to_geant(T const& val, T units)
0074 {
0075     return val * units;
0076 }
0077
0078 //---------------------------------------------------------------------------//
0079 /*!
0080  * Convert a native Celeritas quantity to a Geant4 value.
0081  */
0082 constexpr inline double convert_to_geant(real_type val, double units)
0083 {
0084     return double{val} * units;
0085 }
0086
0087 //---------------------------------------------------------------------------//
0088 /*!
0089  * Convert a native Celeritas 3-vector to a Geant4 equivalent.
0090  */
0091 template<class T>
0092 inline G4ThreeVector convert_to_geant(Array<T, 3> const& arr, double units)
0093 {
0094     return {arr[0] * units, arr[1] * units, arr[2] * units};
0095 }
0096
0097 //! \cond (CELERITAS_DOC_DEV)
0098 //---------------------------------------------------------------------------//
0099 /*!
0100  * Set y += a * x .
0101  */
0102 inline void axpy(double a, G4ThreeVector const& x, G4ThreeVector* y)
0103 {
0104     CELER_EXPECT(y);
0105     for (int i = 0; i < 3; ++i)
0106     {
0107         (*y)[i] = a * x[i] + (*y)[i];
0108     }
0109 }
0110 //! \endcond
0111
0112 //---------------------------------------------------------------------------//
0113 }  // namespace celeritas