Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <boost/math/quaternion.hpp>
       7             : #include <cstddef>
       8             : #include <pup.h>
       9             : 
      10             : #include "ControlSystem/ControlErrors/Expansion.hpp"
      11             : #include "ControlSystem/ControlErrors/Rotation.hpp"
      12             : #include "ControlSystem/Protocols/ControlError.hpp"
      13             : #include "ControlSystem/Tags/QueueTags.hpp"
      14             : #include "ControlSystem/Tags/SystemTags.hpp"
      15             : #include "DataStructures/DataVector.hpp"
      16             : #include "DataStructures/Matrix.hpp"
      17             : #include "Domain/CoordinateMaps/TimeDependent/RotationMatrixHelpers.hpp"
      18             : #include "Domain/Creators/Tags/ObjectCenter.hpp"
      19             : #include "Domain/FunctionsOfTime/QuaternionHelpers.hpp"
      20             : #include "Domain/Structure/ObjectLabel.hpp"
      21             : #include "Options/String.hpp"
      22             : #include "Parallel/GlobalCache.hpp"
      23             : #include "Utilities/EqualWithinRoundoff.hpp"
      24             : #include "Utilities/ErrorHandling/Assert.hpp"
      25             : #include "Utilities/GetOutput.hpp"
      26             : #include "Utilities/ProtocolHelpers.hpp"
      27             : #include "Utilities/TMPL.hpp"
      28             : #include "Utilities/TaggedTuple.hpp"
      29             : 
      30             : /// \cond
      31             : namespace domain::Tags {
      32             : template <size_t Dim>
      33             : struct Domain;
      34             : struct FunctionsOfTime;
      35             : }  // namespace domain::Tags
      36             : /// \endcond
      37             : 
      38             : namespace control_system {
      39             : namespace ControlErrors {
      40             : /*!
      41             :  * \brief Control error in the 3D \link
      42             :  * domain::CoordinateMaps::TimeDependent::Translation Translation \endlink
      43             :  * coordinate map
      44             :  *
      45             :  * \details Computes the error in how much the system has translated. When there
      46             :  * are two excisions, it does this by using a modified version of Eq. (42) from
      47             :  * \cite Ossokine2013zga. The equation is
      48             :  *
      49             :  * \begin{equation}
      50             :  * \left(0, \delta\vec{T}\right) = a\mathbf{q}\left(\frac{1}{2}(\mathbf{x}_A
      51             :  * + \mathbf{x}_B - \frac{1}{2}(\mathbf{c}_A + \mathbf{c}_B)) - \mathbf{\delta
      52             :  * q}\wedge\frac{1}{2}(\mathbf{c}_A + \mathbf{c}_B) - \frac{\delta
      53             :  * a}{a}\frac{1}{2}(\mathbf{c}_A + \mathbf{c}_B) \right)\mathbf{q}^*
      54             :  * \end{equation}
      55             :  *
      56             :  * where object A is located on the positive x-axis in the grid frame, bold face
      57             :  * letters are quaternions, vectors are promoted to quaternions as \f$
      58             :  * \mathbf{v} = (0, \vec{v}) \f$, \f$ \mathbf{q} \f$ is the quaternion from the
      59             :  * \link domain::CoordinateMaps::TimeDependent::Rotation Rotation \endlink map,
      60             :  * \f$ a \f$ is the function \f$ a(t) \f$ from the \link
      61             :  * domain::CoordinateMaps::TimeDependent::CubicScale CubicScale \endlink map,
      62             :  * \f$ \mathbf{\delta q}\wedge\mathbf{c}_A \equiv (0, \delta\vec{q} \times
      63             :  * \vec{c}_A) \f$, \f$ \delta\vec{q} \f$ is the \link
      64             :  * control_system::ControlErrors::Rotation Rotation \endlink control error, and
      65             :  * \f$ \delta a\f$ is the \link control_system::ControlErrors::Expansion
      66             :  * Expansion \endlink control error.
      67             :  *
      68             :  * When there is only a single excision, the control error assumes that the
      69             :  * center of the excision is at the origin. Thus, the control error is just
      70             :  * taken to be the current center of the horizon mapped through the expansion
      71             :  * and rotation maps if there are any.
      72             :  *
      73             :  * Requirements:
      74             :  * - This control error requires that there be either one or two objects in the
      75             :  *   simulation
      76             :  * - Currently this control error can only be used with the \link
      77             :  *   control_system::Systems::Translation Translation \endlink control system
      78             :  * - There must exist an expansion map and a quaternion rotation map in the
      79             :  *   coordinate map with names "Expansion" and "Rotation", respectively if there
      80             :  *   are two object. If there is a single object, then the "Expansion" and
      81             :  *   "Rotation" maps may exist, but don't need to.
      82             :  */
      83             : template <size_t NumberOfObjects>
      84           1 : struct Translation : tt::ConformsTo<protocols::ControlError> {
      85             :   static_assert(NumberOfObjects == 1 or NumberOfObjects == 2,
      86             :                 "Translation control can only work with 1 or 2 objects.");
      87             : 
      88           0 :   using object_centers = tmpl::conditional_t<
      89             :       NumberOfObjects == 1, domain::object_list<domain::ObjectLabel::None>,
      90             :       domain::object_list<domain::ObjectLabel::A, domain::ObjectLabel::B>>;
      91             : 
      92           0 :   using options = tmpl::list<>;
      93           0 :   static constexpr Options::String help{
      94             :       "Computes the control error for translation control. This should not "
      95             :       "take any options."};
      96             : 
      97           0 :   void pup(PUP::er& /*p*/) {}
      98             : 
      99             :   template <typename Metavariables, typename... TupleTags>
     100           0 :   DataVector operator()(const ::TimescaleTuner<true>& /*unused*/,
     101             :                         const Parallel::GlobalCache<Metavariables>& cache,
     102             :                         const double time,
     103             :                         const std::string& /*function_of_time_name*/,
     104             :                         const tuples::TaggedTuple<TupleTags...>& measurements) {
     105             :     const auto& functions_of_time = get<domain::Tags::FunctionsOfTime>(cache);
     106             : 
     107             :     if constexpr (NumberOfObjects == 2) {
     108             :       using quat = boost::math::quaternion<double>;
     109             : 
     110             :       const quat quaternion = datavector_to_quaternion(
     111             :           functions_of_time.at("Rotation")->func(time)[0]);
     112             :       const double expansion_factor =
     113             :           functions_of_time.at("Expansion")->func(time)[0][0];
     114             : 
     115             :       using center_A =
     116             :           control_system::QueueTags::Center<::domain::ObjectLabel::A>;
     117             :       using center_B =
     118             :           control_system::QueueTags::Center<::domain::ObjectLabel::B>;
     119             : 
     120             :       const tnsr::I<double, 3, Frame::Grid>& grid_position_of_A_tnsr =
     121             :           Parallel::get<domain::Tags::ObjectCenter<domain::ObjectLabel::A>>(
     122             :               cache);
     123             :       const DataVector grid_position_of_A{{grid_position_of_A_tnsr[0],
     124             :                                            grid_position_of_A_tnsr[1],
     125             :                                            grid_position_of_A_tnsr[2]}};
     126             :       const DataVector& current_position_of_A = get<center_A>(measurements);
     127             : 
     128             :       const tnsr::I<double, 3, Frame::Grid>& grid_position_of_B_tnsr =
     129             :           Parallel::get<domain::Tags::ObjectCenter<domain::ObjectLabel::B>>(
     130             :               cache);
     131             :       const DataVector grid_position_of_B{{grid_position_of_B_tnsr[0],
     132             :                                            grid_position_of_B_tnsr[1],
     133             :                                            grid_position_of_B_tnsr[2]}};
     134             :       const DataVector& current_position_of_B = get<center_B>(measurements);
     135             : 
     136             :       const DataVector grid_position_average =
     137             :           0.5 * (grid_position_of_A + grid_position_of_B);
     138             :       const DataVector current_position_average =
     139             :           0.5 * (current_position_of_A + current_position_of_B);
     140             : 
     141             :       const DataVector grid_separation =
     142             :           grid_position_of_A - grid_position_of_B;
     143             :       const DataVector current_separation =
     144             :           current_position_of_A - current_position_of_B;
     145             : 
     146             :       // These quantities come from the translation control implementation in
     147             :       // SpEC
     148             :       const double current_separation_dot_grid_separation =
     149             :           dot(current_separation, grid_separation);
     150             :       const double current_separation_dot_grid_average =
     151             :           dot(current_separation, grid_position_average);
     152             :       const double grid_separation_dot_grid_average =
     153             :           dot(grid_separation, grid_position_average);
     154             :       const double grid_separation_dot_grid_separation =
     155             :           dot(grid_separation, grid_separation);
     156             : 
     157             :       // From eq. 42 in 1304.3067 where the grid and current position are
     158             :       // swapped from only object A to the average grid and current positions of
     159             :       // both objects.
     160             :       const DataVector translation_control =
     161             :           expansion_factor *
     162             :           (grid_separation_dot_grid_separation * current_position_average -
     163             :            current_separation_dot_grid_separation * grid_position_average -
     164             :            grid_separation_dot_grid_average * current_separation +
     165             :            current_separation_dot_grid_average * grid_separation) /
     166             :           grid_separation_dot_grid_separation;
     167             :       const quat middle_expression =
     168             :           datavector_to_quaternion(translation_control);
     169             : 
     170             :       // Because we are converting from a quaternion to a DataVector, there will
     171             :       // be four components in the DataVector. However, translation control only
     172             :       // requires three (the latter three to be exact, because the first
     173             :       // component should be 0. We ASSERT this also.)
     174             :       const DataVector result_with_four_components = quaternion_to_datavector(
     175             :           quaternion * middle_expression * conj(quaternion));
     176             :       ASSERT(equal_within_roundoff(result_with_four_components[0], 0.0),
     177             :              "Error in computing translation control error. First component of "
     178             :              "resulting quaternion should be 0.0, but is " +
     179             :                  get_output(result_with_four_components[0]) + " instead.");
     180             : 
     181             :       return {result_with_four_components[1], result_with_four_components[2],
     182             :               result_with_four_components[3]};
     183             :     } else {
     184             :       const DataVector& current_position =
     185             :           get<control_system::QueueTags::Center<::domain::ObjectLabel::None>>(
     186             :               measurements);
     187             :       DataVector result{3, 0.0};
     188             : 
     189             :       double expansion_factor = 1.0;
     190             :       if (functions_of_time.count("Expansion") == 1) {
     191             :         expansion_factor = functions_of_time.at("Expansion")->func(time)[0][0];
     192             :       }
     193             : 
     194             :       if (functions_of_time.count("Rotation") == 1) {
     195             :         const Matrix rot_matrix =
     196             :             rotation_matrix<3>(time, *functions_of_time.at("Rotation").get());
     197             : 
     198             :         for (size_t i = 0; i < 3; i++) {
     199             :           for (size_t j = 0; j < 3; j++) {
     200             :             result[i] += rot_matrix(i, j) * current_position[j];
     201             :           }
     202             :         }
     203             :       } else {
     204             :         result = current_position;
     205             :       }
     206             : 
     207             :       result *= expansion_factor;
     208             : 
     209             :       return result;
     210             :     }
     211             :   }
     212             : };
     213             : }  // namespace ControlErrors
     214             : }  // namespace control_system