Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : #include <cstddef>
       6             : #include "DataStructures/DataBox/Prefixes.hpp"
       7             : #include "DataStructures/Variables.hpp"
       8             : #include "DataStructures/VariablesTag.hpp"
       9             : #include "Evolution/Systems/CurvedScalarWave/Worldtube/Tags.hpp"
      10             : #include "Time/Tags/HistoryEvolvedVariables.hpp"
      11             : #include "Time/TimeSteppers/TimeStepper.hpp"
      12             : #include "Utilities/Gsl.hpp"
      13             : /// \cond
      14             : namespace Tags {
      15             : template <typename StepperInterface>
      16             : struct TimeStepper;
      17             : }  // namespace Tags
      18             : /// \endcond
      19             : namespace CurvedScalarWave::Worldtube::Initialization {
      20             : /*!
      21             :  * \brief Initializes the time stepper and evolved variables used by the
      22             :  * worldtube system. Also sets `Tags::CurrentIteration` to 0.
      23             :  *
      24             :  * \details Sets the initial position and velocity of the particle to the values
      25             :  * specified in the input file. The time stepper history is set analogous to the
      26             :  * elements which use the same time stepper.
      27             :  */
      28           1 : struct InitializeEvolvedVariables {
      29           0 :   static constexpr size_t Dim = 3;
      30           0 :   using variables_tag = ::Tags::Variables<
      31             :       tmpl::list<Tags::EvolvedPosition<Dim>, Tags::EvolvedVelocity<Dim>>>;
      32           0 :   using dt_variables_tag = db::add_tag_prefix<::Tags::dt, variables_tag>;
      33             : 
      34           0 :   using simple_tags =
      35             :       tmpl::list<variables_tag, dt_variables_tag, Tags::CurrentIteration,
      36             :                  Tags::ExpirationTime, Tags::WorldtubeRadius,
      37             :                  ::Tags::HistoryEvolvedVariables<variables_tag>>;
      38           0 :   using return_tags = simple_tags;
      39             : 
      40           0 :   using compute_tags = tmpl::list<>;
      41           0 :   using const_global_cache_tags = tmpl::list<>;
      42           0 :   using mutable_global_cache_tags = tmpl::list<>;
      43           0 :   using simple_tags_from_options = tmpl::list<Tags::InitialPositionAndVelocity>;
      44           0 :   using argument_tags = tmpl::list<::Tags::TimeStepper<TimeStepper>,
      45             :                                    Tags::InitialPositionAndVelocity,
      46             :                                    ::Tags::Time, Tags::ExcisionSphere<Dim>>;
      47           0 :   static void apply(
      48             :       const gsl::not_null<Variables<
      49             :           tmpl::list<Tags::EvolvedPosition<Dim>, Tags::EvolvedVelocity<Dim>>>*>
      50             :           evolved_vars,
      51             :       const gsl::not_null<
      52             :           Variables<tmpl::list<::Tags::dt<Tags::EvolvedPosition<Dim>>,
      53             :                                ::Tags::dt<Tags::EvolvedVelocity<Dim>>>>*>
      54             :           dt_evolved_vars,
      55             :       const gsl::not_null<size_t*> current_iteration,
      56             :       const gsl::not_null<double*> expiration_time,
      57             :       const gsl::not_null<double*> worldtube_radius,
      58             :       const gsl::not_null<::Tags::HistoryEvolvedVariables<variables_tag>::type*>
      59             :           time_stepper_history,
      60             :       const TimeStepper& time_stepper,
      61             :       const std::array<tnsr::I<double, Dim>, 2>& initial_pos_and_vel,
      62             :       const double initial_time, const ExcisionSphere<Dim>& excision_sphere) {
      63             :     *current_iteration = 0;
      64             : 
      65             :     // the functions of time should be ready during the first step but not the
      66             :     // second. We choose the arbitrary value of 1e-10 here to ensure this.
      67             :     *expiration_time = initial_time + 1e-10;
      68             :     *worldtube_radius = excision_sphere.radius();
      69             : 
      70             :     const size_t starting_order =
      71             :         visit(
      72             :             []<typename Tag>(
      73             :                 const std::pair<tmpl::type_<Tag>, typename Tag::type&&> order) {
      74             :               if constexpr (std::is_same_v<Tag,
      75             :                                            TimeSteppers::Tags::FixedOrder>) {
      76             :                 return order.second;
      77             :               } else {
      78             :                 return order.second.minimum;
      79             :               }
      80             :             },
      81             :             time_stepper.order()) -
      82             :         time_stepper.number_of_past_steps();
      83             :     *time_stepper_history =
      84             :         typename ::Tags::HistoryEvolvedVariables<variables_tag>::type{
      85             :             starting_order};
      86             :     evolved_vars->initialize(size_t(1), 0.);
      87             :     dt_evolved_vars->initialize(size_t(1), 0.);
      88             :     for (size_t i = 0; i < Dim; ++i) {
      89             :       get<Tags::EvolvedPosition<Dim>>(*evolved_vars).get(i)[0] =
      90             :           initial_pos_and_vel.at(0).get(i);
      91             :       get<Tags::EvolvedVelocity<Dim>>(*evolved_vars).get(i)[0] =
      92             :           initial_pos_and_vel.at(1).get(i);
      93             :     }
      94             :   }
      95             : };
      96             : }  // namespace CurvedScalarWave::Worldtube::Initialization