Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <cstddef>
       7             : 
       8             : #include "DataStructures/DataBox/DataBox.hpp"
       9             : #include "DataStructures/Tensor/Tensor.hpp"
      10             : #include "DataStructures/Variables.hpp"
      11             : #include "Domain/Tags.hpp"
      12             : #include "Evolution/Systems/CurvedScalarWave/Worldtube/Tags.hpp"
      13             : #include "NumericalAlgorithms/SphericalHarmonics/Tags.hpp"
      14             : #include "Parallel/AlgorithmExecution.hpp"
      15             : #include "Parallel/GlobalCache.hpp"
      16             : #include "PointwiseFunctions/GeneralRelativity/Tags.hpp"
      17             : #include "Utilities/Gsl.hpp"
      18             : #include "Utilities/TMPL.hpp"
      19             : 
      20             : namespace CurvedScalarWave::Worldtube {
      21             : 
      22             : /// @{
      23             : /*!
      24             :  * \brief Calculates the time derivative of `Psi0`, the constant coefficient of
      25             :  * the expansion of `Psi`.
      26             :  *
      27             :  * \details The derivation comes from expanding the scalar wave equation to
      28             :  * second order and reads
      29             :  *
      30             :  * \f{equation}
      31             :  * g^{00}_0 \ddot{\Psi}^R_0(t_s) + 2 g_0^{0i}
      32             :  * \dot{\Psi}^N_i(t_s) + 2 g_0^{ij} \Psi^N_{\langle ij \rangle}(t_s)
      33             :  * + \frac{2 \delta_{ij}  g_0^{ij}}{R^2}
      34             :  * \left(\Psi^N_0(t_s) - \Psi^R_0(t_s) \right) -
      35             :  * \Gamma_0^0\dot{\Psi}R_0(t_s) -  \Gamma_0^i \Psi_i^N(t_s) = 0.
      36             :  *\f}
      37             :  *
      38             :  * Here, \f$ \Gamma^\mu_0 \f$ and \f$ g^{\mu \nu}_0 \f$ are the trace of the
      39             :  * spacetime Christoffel symbol and the inverse spacetime metric, respectively,
      40             :  * evaluated at the position of the particle; \f$\Psi^N_0\f$, \f$\Psi^N_i\f$,
      41             :  * \f$\Psi^N_\langle i j \rangle\f$ are the monopole, dipole and quadrupole of
      42             :  * the regular field on the worldtube boundary transformed to symmetric
      43             :  * trace-free tensors and \f$ R\f$ is the worldtube radius.
      44             :  */
      45           1 : struct TimeDerivativeMutator {
      46           0 :   static constexpr size_t Dim = 3;
      47             : 
      48           0 :   using variables_tag = ::Tags::Variables<tmpl::list<Tags::Psi0, Tags::dtPsi0>>;
      49           0 :   using dt_variables_tag = db::add_tag_prefix<::Tags::dt, variables_tag>;
      50           0 :   using return_tags = tmpl::list<dt_variables_tag>;
      51           0 :   using argument_tags = tmpl::list<
      52             :       variables_tag,
      53             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 0, Dim, Frame::Grid>,
      54             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 1, Dim, Frame::Grid>,
      55             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 2, Dim, Frame::Grid>,
      56             :       Stf::Tags::StfTensor<::Tags::dt<Tags::PsiWorldtube>, 1, Dim, Frame::Grid>,
      57             :       gr::Tags::InverseSpacetimeMetric<double, Dim, Frame::Grid>,
      58             :       gr::Tags::TraceSpacetimeChristoffelSecondKind<double, Dim, Frame::Grid>,
      59             :       Tags::ExcisionSphere<Dim>>;
      60             : 
      61           0 :   static void apply(
      62             :       const gsl::not_null<Variables<
      63             :           tmpl::list<::Tags::dt<Tags::Psi0>, ::Tags::dt<Tags::dtPsi0>>>*>
      64             :           dt_evolved_vars,
      65             :       const Variables<tmpl::list<Tags::Psi0, Tags::dtPsi0>>& evolved_vars,
      66             :       const Scalar<double>& psi_monopole,
      67             :       const tnsr::i<double, Dim, Frame::Grid>& psi_dipole,
      68             :       const tnsr::ii<double, Dim, Frame::Grid>& psi_quadrupole,
      69             :       const tnsr::i<double, Dim, Frame::Grid>& dt_psi_dipole,
      70             :       const tnsr::AA<double, Dim, Frame::Grid>& inverse_spacetime_metric,
      71             :       const tnsr::A<double, Dim, Frame::Grid>& trace_spacetime_christoffel,
      72             :       const ExcisionSphere<Dim>& excision_sphere);
      73             : };
      74             : 
      75             : namespace Actions {
      76           0 : struct ComputeTimeDerivative {
      77           0 :   static constexpr size_t Dim = 3;
      78           0 :   using variables_tag = ::Tags::Variables<tmpl::list<Tags::Psi0, Tags::dtPsi0>>;
      79           0 :   using dt_variables_tag = db::add_tag_prefix<::Tags::dt, variables_tag>;
      80           0 :   using simple_tags = tmpl::list<
      81             :       dt_variables_tag, variables_tag,
      82             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 0, Dim, Frame::Grid>,
      83             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 1, Dim, Frame::Grid>,
      84             :       Stf::Tags::StfTensor<Tags::PsiWorldtube, 2, Dim, Frame::Grid>,
      85             :       Stf::Tags::StfTensor<::Tags::dt<Tags::PsiWorldtube>, 1, Dim, Frame::Grid>,
      86             :       gr::Tags::InverseSpacetimeMetric<double, Dim, Frame::Grid>,
      87             :       gr::Tags::TraceSpacetimeChristoffelSecondKind<double, Dim, Frame::Grid>>;
      88             : 
      89             :   template <typename DbTagsList, typename... InboxTags, typename Metavariables,
      90             :             typename ArrayIndex, typename ActionList,
      91             :             typename ParallelComponent>
      92           0 :   static Parallel::iterable_action_return_t apply(
      93             :       db::DataBox<DbTagsList>& box,
      94             :       tuples::TaggedTuple<InboxTags...>& /*inboxes*/,
      95             :       Parallel::GlobalCache<Metavariables>& /*cache*/,
      96             :       const ArrayIndex& /*array_index*/, ActionList /*meta*/,
      97             :       const ParallelComponent* /*meta*/) {
      98             :     if (db::get<Tags::ExpansionOrder>(box) >= 2) {
      99             :       db::mutate_apply<TimeDerivativeMutator>(make_not_null(&box));
     100             :     }
     101             :     return {Parallel::AlgorithmExecution::Continue, std::nullopt};
     102             :   }
     103             : };
     104             : /// @}
     105             : 
     106             : }  // namespace Actions
     107             : }  // namespace CurvedScalarWave::Worldtube