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 SolverPLS_H__
#define SolverPLS_H__
 
#define BOOST_ALLOW_DEPRECATED_HEADERS
 
#include <deal.II/base/function.h>
#include <deal.II/grid/grid_generator.h>
#include <deal.II/grid/grid_in.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 SolverPLS
  : public SettingsPLS
  , public Solver<dim>
{
public:
  SolverPLS() = delete;
 
  SolverPLS(unsigned int p, unsigned int r, std::string fname)
    : Solver<dim>(p,
                  1,
                  1,
                  fname,
                  &exact_solution,
                  false,
                  false,
                  print_time_tables,
                  project_exact_solution)
    , r(r)
    , fname(fname)
  {
    TimerOutput::OutputFrequency tf =
      (print_time_tables) ? TimerOutput::summary : TimerOutput::never;
 
    TimerOutput timer(std::cout, tf, TimerOutput::cpu_and_wall_times_grouped);
 
    {
      TMR("Solver run");
      Solver<dim>::run();
    }
  }
 
  ~SolverPLS() = default;
 
private:
  const unsigned int r;
  const std::string fname;
 
  const ExactSolutionPLS_PHI<dim> exact_solution;
 
  virtual void make_mesh() override final;
  virtual void fill_dirichlet_stack() override final;
  virtual void solve() override final;
};
 
template<int dim>
void
SolverPLS<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