discretization.h

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//
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Copyright (C) 2020 - 2026 by the ryujin authors
//
 
#pragma once
 
#include <ryujin/base/compile_time_options.h>
#include <ryujin/base/convenience_macros.h>
#include <ryujin/base/mpi_ensemble.h>
#include <ryujin/base/patterns_conversion.h>
#include <ryujin/geometries/geometry.h>
 
#include <deal.II/base/exceptions.h>
#include <deal.II/base/parameter_acceptor.h>
#include <deal.II/base/point.h>
#include <deal.II/base/types.h>
#include <deal.II/distributed/fully_distributed_tria.h>
#include <deal.II/distributed/shared_tria.h>
#include <deal.II/distributed/tria.h>
#include <deal.II/fe/mapping_q_cache.h>
#include <deal.II/grid/tria.h>
#include <deal.II/hp/fe_collection.h>
#include <deal.II/hp/mapping_collection.h>
#include <deal.II/hp/q_collection.h>
 
#include <functional>
#include <memory>
#include <string>
#include <vector>
 
namespace ryujin
{
  enum Boundary : dealii::types::boundary_id {
    do_nothing = 0,
 
    periodic = 1,
 
    slip = 2,
 
    no_slip = 3,
 
    dirichlet = 4,
 
    dynamic = 5,
 
    dirichlet_momentum = 6,
 
    dirichlet_velocity = 7
  };
 
 
  enum class Ansatz {
    cg_q1,
 
    cg_q2,
 
    cg_q3,
 
    dg_q1,
 
    dg_q2,
 
    dg_q3
  };
} // namespace ryujin
 
#ifndef DOXYGEN
DECLARE_ENUM(ryujin::Boundary,
             LIST({ryujin::Boundary::do_nothing, "do nothing"},
                  {ryujin::Boundary::periodic, "periodic"},
                  {ryujin::Boundary::slip, "slip"},
                  {ryujin::Boundary::no_slip, "no slip"},
                  {ryujin::Boundary::dirichlet, "dirichlet"},
                  {ryujin::Boundary::dynamic, "dynamic"},
                  {ryujin::Boundary::dirichlet_momentum, "dirichlet momentum"},
                  {ryujin::Boundary::dirichlet_velocity,
                   "dirichlet velocity"}));
 
DECLARE_ENUM(ryujin::Ansatz,
             LIST({ryujin::Ansatz::cg_q1, "cG Q1"},
                  {ryujin::Ansatz::cg_q2, "cG Q2"},
                  {ryujin::Ansatz::cg_q3, "cG Q3"},
                  {ryujin::Ansatz::dg_q1, "dG Q1"},
                  {ryujin::Ansatz::dg_q2, "dG Q2"},
                  {ryujin::Ansatz::dg_q3, "dG Q3"}));
#endif
 
namespace ryujin
{
  enum class MeshType {
    serial,
    parallel_shared,
    parallel_distributed,
    parallel_fullydistributed
  };
} // namespace ryujin
 
#ifndef DOXYGEN
DECLARE_ENUM(ryujin::MeshType,
             LIST({ryujin::MeshType::serial, "serial"},
                  {ryujin::MeshType::parallel_shared, "parallel shared"},
                  {ryujin::MeshType::parallel_distributed,
                   "parallel distributed"},
                  {ryujin::MeshType::parallel_fullydistributed,
                   "parallel fullydistributed"}));
#endif
 
namespace ryujin
{
  template <int dim>
  class Discretization final : public dealii::ParameterAcceptor
  {
  public:
 
    struct Collection {
      std::unique_ptr<const dealii::hp::MappingCollection<dim>> mapping;
      std::unique_ptr<const dealii::hp::FECollection<dim>> finite_element_cg;
      std::unique_ptr<const dealii::hp::FECollection<dim>> finite_element_dg;
      std::unique_ptr<const dealii::hp::QCollection<dim>> quadrature;
      std::unique_ptr<const dealii::hp::QCollection<dim>> quadrature_high_order;
      std::unique_ptr<const dealii::hp::QCollection<dim>> nodal_quadrature;
      std::unique_ptr<const dealii::hp::QCollection<1>> quadrature_1d;
      std::unique_ptr<const dealii::hp::QCollection<1>> nodal_quadrature_1d;
      std::unique_ptr<const std::vector<dealii::hp::QCollection<dim - 1>>>
          face_quadrature;
      std::unique_ptr<const std::vector<dealii::hp::QCollection<dim - 1>>>
          face_nodal_quadrature;
    };
 
    using Transformation = std::function<dealii::Point<dim>(
        const typename dealii::Triangulation<dim>::cell_iterator &,
        const dealii::Point<dim> &)>;
 
 
 
    Discretization(const MPIEnsemble &mpi_ensemble,
                   const std::string &subsection = "/Discretization");
 
    void prepare(const std::string &base_name);
 
    void update_mapping();
 
 
 
    ACCESSOR_READ_ONLY(selected_geometry)
 
    
    ACCESSOR_READ_ONLY(ansatz)
 
    
    bool have_discontinuous_ansatz() const
    {
      switch (ansatz_) {
        /* Continuous Ansatz: */
      case Ansatz::cg_q1:
        [[fallthrough]];
      case Ansatz::cg_q2:
        [[fallthrough]];
      case Ansatz::cg_q3:
        return false;
 
        /* Discontinuous Ansatz: */
      case Ansatz::dg_q1:
        [[fallthrough]];
      case Ansatz::dg_q2:
        [[fallthrough]];
      case Ansatz::dg_q3:
        return true;
      }
 
      AssertThrow(false, dealii::ExcInternalError());
      __builtin_trap();
    }
 
    unsigned int polynomial_degree() const
    {
      switch (ansatz_) {
      case Ansatz::cg_q1:
        [[fallthrough]];
      case Ansatz::dg_q1:
        return 1;
      case Ansatz::cg_q2:
        [[fallthrough]];
      case Ansatz::dg_q2:
        return 2;
      case Ansatz::cg_q3:
        [[fallthrough]];
      case Ansatz::dg_q3:
        return 3;
      }
 
      AssertThrow(false, dealii::ExcInternalError());
      __builtin_trap();
    }
 
    ACCESSOR(refinement)
 
    
    bool has_triangulation() const
    {
      return triangulation_ != nullptr;
    }
 
    ACCESSOR(triangulation)
 
    
    ACCESSOR_READ_ONLY(triangulation)
 
    
    ACCESSOR(transformation)
 
    
    ACCESSOR_READ_ONLY(transformation)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, mapping)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, finite_element_cg)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, finite_element_dg)
 
    
    const dealii::hp::FECollection<dim> &finite_element() const
    {
      if (have_discontinuous_ansatz())
        return *collection_.finite_element_dg;
      else
        return *collection_.finite_element_cg;
    }
 
    ACCESSOR_CONTAINER_READ_ONLY(collection_, quadrature)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, quadrature_high_order)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, nodal_quadrature)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, quadrature_1d)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, nodal_quadrature_1d)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, face_quadrature)
 
    
    ACCESSOR_CONTAINER_READ_ONLY(collection_, face_nodal_quadrature)
 
    //@}
 
  private:
 
    Ansatz ansatz_;
    MeshType mesh_type_;
 
    std::string geometry_;
 
    unsigned int refinement_;
 
    bool mesh_writeout_;
    double mesh_distortion_;
 
 
 
    const MPIEnsemble &mpi_ensemble_;
 
    std::vector<std::unique_ptr<Geometry<dim>>> geometry_list_;
    Geometry<dim> *selected_geometry_ = nullptr;
 
    std::unique_ptr<dealii::Triangulation<dim>> triangulation_;
 
    Collection collection_;
    typename Geometry<dim>::HP_Collection collection_type_ =
        Geometry<dim>::HP_Collection::standard_quadrilaterals;
 
    std::shared_ptr<dealii::MappingQCache<dim>> mapping_cache_;
    Transformation transformation_;
 
 
    void create_mapping_cache();
  };
} // namespace ryujin