Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <array>
       7             : #include <cmath>
       8             : #include <limits>
       9             : #include <tuple>
      10             : 
      11             : #include "DataStructures/DataBox/DataBox.hpp"
      12             : #include "IO/Observer/ObserverComponent.hpp"
      13             : #include "IO/Observer/ReductionActions.hpp"
      14             : #include "NumericalAlgorithms/SphericalHarmonics/Spherepack.hpp"
      15             : #include "NumericalAlgorithms/SphericalHarmonics/Strahlkorper.hpp"
      16             : #include "NumericalAlgorithms/SphericalHarmonics/Tags.hpp"
      17             : #include "Parallel/GlobalCache.hpp"
      18             : #include "Parallel/Invoke.hpp"
      19             : #include "Parallel/ParallelComponentHelpers.hpp"
      20             : #include "ParallelAlgorithms/ApparentHorizonFinder/FastFlow.hpp"
      21             : #include "ParallelAlgorithms/ApparentHorizonFinder/Protocols/Callback.hpp"
      22             : #include "ParallelAlgorithms/ApparentHorizonFinder/Tags.hpp"
      23             : #include "PointwiseFunctions/GeneralRelativity/Surfaces/Tags.hpp"
      24             : #include "Utilities/Gsl.hpp"
      25             : #include "Utilities/PrettyType.hpp"
      26             : #include "Utilities/ProtocolHelpers.hpp"
      27             : 
      28             : /// \cond
      29             : namespace Frame {
      30             : struct Grid;
      31             : struct Distorted;
      32             : struct Inertial;
      33             : }  // namespace Frame
      34             : /// \endcond
      35             : 
      36             : namespace ah::callbacks {
      37             : /*!
      38             :  * \brief Writes the center of an apparent horizon to disk in both the
      39             :  * `Frame` template parameter frame and Frame::Inertial frame. Intended to be
      40             :  * used in the `horizon_find_callbacks` list of a
      41             :  * `ah::protocols::HorizonMetavars`.
      42             :  *
      43             :  * The centers will be written to a subfile with the name
      44             :  * `/ApparentHorizons/TargetName_Centers.dat` where `TargetName` is the
      45             :  * pretty_type::name of the \p HorizonMetavars template parameter.
      46             :  *
      47             :  * The columns of the dat file are:
      48             :  * - %Time
      49             :  * - GridCenter_x
      50             :  * - GridCenter_y
      51             :  * - GridCenter_z
      52             :  * - InertialCenter_x
      53             :  * - InertialCenter_y
      54             :  * - InertialCenter_z
      55             :  *
      56             :  * The `Frame` template parameter must be either `::Frame::Grid` or
      57             :  * `::Frame::Distorted`. Even though the template parameter can be
      58             :  * `::Frame::Distorted`, we still write `GridCenter_?` because the centers of
      59             :  * the objects are the same in the Grid and Distorted frames.
      60             :  *
      61             :  * \note Requires `ylm::Tags::Strahlkorper<Frame>` and
      62             :  * `ylm::Tags::CartesianCoords<Frame::Inertial>` and
      63             :  * `ylm::Tags::EuclideanAreaElement<Frame>` to be in the DataBox of the horizon
      64             :  * finder.
      65             :  */
      66             : template <typename HorizonMetavars>
      67           1 : struct ObserveCenters : tt::ConformsTo<ah::protocols::Callback> {
      68             :   template <typename DbTags, typename Metavariables>
      69           0 :   static void apply(const db::DataBox<DbTags>& box,
      70             :                     Parallel::GlobalCache<Metavariables>& cache,
      71             :                     const FastFlow::Status /*status*/) {
      72             :     using frame = typename HorizonMetavars::frame;
      73             :     static_assert(std::is_same_v<frame, ::Frame::Grid> or
      74             :                       std::is_same_v<frame, ::Frame::Distorted>,
      75             :                   "Frame must be either Grid or Distorted.");
      76             :     using HorizonTag = ylm::Tags::Strahlkorper<frame>;
      77             :     using CoordsTag = ylm::Tags::CartesianCoords<::Frame::Inertial>;
      78             :     using EuclideanAreaElementTag = ylm::Tags::EuclideanAreaElement<frame>;
      79             :     static_assert(db::tag_is_retrievable_v<HorizonTag, db::DataBox<DbTags>>,
      80             :                   "DataBox must contain ylm::Tags::Strahlkorper<Frame>");
      81             :     static_assert(db::tag_is_retrievable_v<CoordsTag, db::DataBox<DbTags>>,
      82             :                   "DataBox must contain "
      83             :                   "ylm::Tags::CartesianCoords<Frame::Inertial>");
      84             :     static_assert(
      85             :         db::tag_is_retrievable_v<EuclideanAreaElementTag, db::DataBox<DbTags>>,
      86             :         "DataBox must contain ylm::Tags::EuclideanAreaElement<Frame>");
      87             : 
      88             :     // Only print the centers if we want to.
      89             :     if (not Parallel::get<ah::Tags::ObserveCenters>(cache)) {
      90             :       return;
      91             :     }
      92             : 
      93             :     const auto& grid_horizon = db::get<HorizonTag>(box);
      94             :     const std::array<double, 3> grid_center = grid_horizon.physical_center();
      95             : 
      96             :     // computes the inertial center to be the average value of the
      97             :     // inertial coordinates over the Strahlkorper, where the average is
      98             :     // computed by a surface integral.
      99             :     // Note that we use the Euclidean area element here, since we are trying
     100             :     // to find a geometric center of a surface without regard to GR.
     101             :     const auto& inertial_coords = db::get<CoordsTag>(box);
     102             :     const auto& area_element = db::get<EuclideanAreaElementTag>(box);
     103             :     std::array<double, 3> inertial_center =
     104             :         make_array<3>(std::numeric_limits<double>::signaling_NaN());
     105             :     auto integrand = make_with_value<Scalar<DataVector>>(get(area_element), 0.);
     106             :     const double denominator = grid_horizon.ylm_spherepack().definite_integral(
     107             :         get(area_element).data());
     108             :     for (size_t i = 0; i < 3; ++i) {
     109             :       get(integrand) = get(area_element) * inertial_coords.get(i);
     110             :       gsl::at(inertial_center, i) =
     111             :           grid_horizon.ylm_spherepack().definite_integral(
     112             :               get(integrand).data()) /
     113             :           denominator;
     114             :     }
     115             : 
     116             :     // time, grid_x, grid_y, grid_z, inertial_x, inertial_y, inertial_z
     117             :     const auto& current_time = db::get<ah::Tags::CurrentTime>(box).value();
     118             :     const auto center_tuple = std::make_tuple(
     119             :         current_time.id, grid_center[0], grid_center[1], grid_center[2],
     120             :         inertial_center[0], inertial_center[1], inertial_center[2]);
     121             : 
     122             :     auto& observer_writer_proxy = Parallel::get_parallel_component<
     123             :         observers::ObserverWriter<Metavariables>>(cache);
     124             : 
     125             :     const std::string subfile_path{"/ApparentHorizons/" +
     126             :                                    HorizonMetavars::name() + "_Centers"};
     127             : 
     128             :     Parallel::threaded_action<
     129             :         observers::ThreadedActions::WriteReductionDataRow>(
     130             :         // Node 0 is always the writer
     131             :         observer_writer_proxy[0], subfile_path, legend_, center_tuple);
     132             :   }
     133             : 
     134             :  private:
     135           0 :   const static inline std::vector<std::string> legend_{
     136             :       {"Time", "GridCenter_x", "GridCenter_y", "GridCenter_z",
     137             :        "InertialCenter_x", "InertialCenter_y", "InertialCenter_z"}};
     138             : };
     139             : }  // namespace ah::callbacks