solver.hpp

/******************************************************************************
 * Copyright (C) Siarhei Uzunbajakau, 2023.
 *
 * This program is free software. You can use, modify, and redistribute it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 or (at your option) any later version.
 * This program is distributed without any warranty.
 *
 * Refer to COPYING.LESSER for more details.
 ******************************************************************************/
 
#ifndef SolverSLDII_H__
#define SolverSLDII_H__
 
#define BOOST_ALLOW_DEPRECATED_HEADERS
 
#include <deal.II/base/function.h>
#include <deal.II/grid/grid_in.h>
#include <deal.II/grid/grid_out.h>
#include <deal.II/grid/grid_tools.h>
#include <deal.II/grid/manifold_lib.h>
 
#include <deal.II/numerics/fe_field_function.h>
 
#include "exact_solution.hpp"
#include "settings.hpp"
#include "static_scalar_solver.hpp"
 
#define TMR(__name) TimerOutput::Scope timer_section(timer, __name)
 
using namespace StaticScalarSolver;
 
template<int dim>
class SolverSLDII
  : public SettingsSLDII
  , public Solver<dim>
{
public:
  SolverSLDII() = delete;
  SolverSLDII(unsigned int p,
              unsigned int mapping_degree,
              unsigned int r,
              std::string fname)
    : Solver<dim>(p,
                  mapping_degree,
                  0,
                  fname,
                  &exact_solution,
                  false,
                  false,
                  print_time_tables,
                  project_exact_solution,
                  true)
    , r(r)
    , fname(fname)
  {
    Solver<dim>::run();
  }
 
  ~SolverSLDII() = default;
 
private:
  const unsigned int r;
  const std::string fname;
 
  const ExactSolutionSLDII_THETA<dim> exact_solution;
  const Functions::ZeroFunction<dim> dirichlet;
 
  SphericalManifold<dim> sphere;
 
  virtual void make_mesh() override final;
  virtual void fill_dirichlet_stack() override final;
  virtual void solve() override final;
 
  void mark_materials();
};
 
template<int dim>
void
SolverSLDII<dim>::fill_dirichlet_stack()
{
  switch (type_of_bc) {
    case Dirichlet:
      Solver<dim>::dirichlet_stack = { { bid, &dirichlet } };
      break;
    case Exact:
      Solver<dim>::dirichlet_stack = { { bid, &exact_solution } };
      break;
  }
}
 
template<int dim>
void
SolverSLDII<dim>::make_mesh()
{
  GridIn<dim> gridin;
  gridin.attach_triangulation(Solver<dim>::triangulation);
 
  std::string fname_mesh =
    (dim == 2) ? "../../gmsh/data/square_r" + std::to_string(r) + ".msh"
               : "../../gmsh/data/cube_r" + std::to_string(r) + ".msh";
 
  std::ifstream ifs(fname_mesh);
  gridin.read_msh(ifs);
 
  mark_materials();
}
 
template<int dim>
void
SolverSLDII<dim>::mark_materials()
{
  Solver<dim>::triangulation.reset_all_manifolds();
 
  for (auto cell : Solver<dim>::triangulation.active_cell_iterators()) {
    if (cell->center().norm() < a) {
      // The cell is inside the shield.
      cell->set_material_id(mid_1);
    } else if (cell->center().norm() < b) {
      // The cell is in the wall of the shield.
      cell->set_material_id(mid_2);
    } else {
      // The cell is outside the shield.
      cell->set_material_id(mid_3);
    }
 
    for (unsigned int f = 0; f < GeometryInfo<dim>::faces_per_cell; ++f) {
      double dif_norm_a = 0.0;
      double dif_norm_b = 0.0;
      double dif_norm = 0.0;
      for (unsigned int v = 0; v < GeometryInfo<dim>::vertices_per_face; v++) {
        dif_norm_a += std::abs(cell->face(f)->vertex(v).norm() - a);
        dif_norm_b += std::abs(cell->face(f)->vertex(v).norm() - b);
        dif_norm += std::abs(cell->face(f)->vertex(0).norm() -
                             cell->face(f)->vertex(v).norm());
      }
 
      if ((dif_norm_a < eps) && (std::abs(cell->center().norm()) < a)) {
        // The face belongs to the interface Gamma_1
        cell->face(f)->set_user_index(1);
        cell->set_user_index(1);
      }
 
      if ((dif_norm_b < eps) && (std::abs(cell->center().norm()) < b)) {
        // The face belongs to the interface Gamma_2
        cell->face(f)->set_user_index(2);
        cell->set_user_index(2);
      }
 
      if ((dif_norm < eps) && (cell->center().norm() > rd1) &&
          (cell->center().norm() < b))
        cell->face(f)->set_all_manifold_ids(1);
    }
  }
 
  Solver<dim>::triangulation.set_manifold(1, sphere);
}
 
template<int dim>
void
SolverSLDII<dim>::solve()
{
  SolverControl control(Solver<dim>::system_rhs.size(),
                        1e-8 * Solver<dim>::system_rhs.l2_norm(),
                        false,
                        false);
 
  if (log_cg_convergence)
    control.enable_history_data();
 
  GrowingVectorMemory<Vector<double>> memory;
  SolverCG<Vector<double>> cg(control, memory);
 
  PreconditionJacobi<SparseMatrix<double>> preconditioner;
  preconditioner.initialize(Solver<dim>::system_matrix, 1.0);
 
  cg.solve(Solver<dim>::system_matrix,
           Solver<dim>::solution,
           Solver<dim>::system_rhs,
           preconditioner);
 
  Solver<dim>::constraints.distribute(Solver<dim>::solution);
 
  if (log_cg_convergence) {
    const std::vector<double> history_data = control.get_history_data();
 
    std::ofstream ofs(fname + "_cg_convergence.csv");
 
    unsigned int i = 1;
    for (auto item : history_data) {
      ofs << i << ", " << item << "\n";
      i++;
    }
    ofs.close();
  }
}
 
#endif