particle_calculation.h

/*  ______________________________________________________________________
 *
 *  ExaDG - High-Order Discontinuous Galerkin for the Exa-Scale
 *
 *  Copyright (C) 2025 by the ExaDG authors
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program. If not, see <https://www.gnu.org/licenses/>.
 *  ______________________________________________________________________
 */
 
#ifndef EXADG_POSTPROCESSOR_PARTICLE_CALCULATION_H_
#define EXADG_POSTPROCESSOR_PARTICLE_CALCULATION_H_
 
// deal.II
#include <deal.II/matrix_free/matrix_free.h>
#include <deal.II/particles/particle_handler.h>
 
// ExaDG
#include <exadg/matrix_free/integrators.h>
#include <exadg/postprocessor/time_control.h>
#include <exadg/utilities/print_functions.h>
 
namespace ExaDG
{
struct ParticleData
{
  ParticleData() : directory("output/"), filename("particle")
  {
  }
 
  void
  print(dealii::ConditionalOStream & pcout)
  {
    if(time_control_data.is_active)
    {
      pcout << std::endl << "  Trace particles:" << std::endl;
 
      // only implemented for unsteady problem
      time_control_data.print(pcout, true /*unsteady*/);
 
      print_parameter(pcout, "Directory of output files", directory);
      print_parameter(pcout, "Filename", filename);
    }
  }
 
  TimeControlData time_control_data;
 
  // directory and filename
  std::string directory;
  std::string filename;
 
  // Starting points of particles
  std::vector<dealii::Point<2>> starting_points_2d;
  std::vector<dealii::Point<3>> starting_points_3d;
};
 
template<int dim, typename Number>
class ParticleCalculator
{
public:
  typedef dealii::LinearAlgebra::distributed::Vector<Number> VectorType;
 
  typedef dealii::VectorizedArray<Number>                         scalar;
  typedef dealii::Tensor<1, dim, dealii::VectorizedArray<Number>> vector;
  typedef dealii::Tensor<2, dim, dealii::VectorizedArray<Number>> tensor;
 
  ParticleCalculator(MPI_Comm const & comm);
 
  void
  setup(dealii::DoFHandler<dim> const & dof_handler_in,
        dealii::Mapping<dim> const &    mapping_in,
        ParticleData const &            particle_data_in);
 
  void
  evaluate(VectorType const & velocity, double const time, bool const print_output);
 
  TimeControl time_control;
 
protected:
  void
  track_lost_particle(const typename dealii::Particles::ParticleIterator<dim> &         particle,
                      const typename dealii::Triangulation<dim>::active_cell_iterator & cell);
 
 
  MPI_Comm const mpi_comm;
 
  dealii::ObserverPointer<dealii::DoFHandler<dim> const> dof_handler;
  dealii::ObserverPointer<dealii::Mapping<dim> const>    mapping;
 
  ParticleData data;
  double       old_time;
 
  unsigned int                                       lost_paticles;
  std::vector<std::vector<dealii::BoundingBox<dim>>> global_bounding_boxes;
 
  dealii::Vector<Number>                  solution_values;
  dealii::Particles::ParticleHandler<dim> particle_handler;
};
 
} // namespace ExaDG
 
#endif /* EXADG_POSTPROCESSOR_PARTICLE_CALCULATION_H_ */