marked_vertices.h

/*  ______________________________________________________________________
 *
 *  ExaDG - High-Order Discontinuous Galerkin for the Exa-Scale
 *
 *  Copyright (C) 2021 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_GRID_MARKED_VERTICES_H_
#define EXADG_GRID_MARKED_VERTICES_H_
 
// deal.II
#include <deal.II/grid/tria.h>

template<int dim>
std::vector<bool>
get_marked_vertices_via_boundary_ids(dealii::Triangulation<dim> const &           triangulation,
                                     std::set<dealii::types::boundary_id> const & boundary_ids)
{
  // mark vertices at interface in order to make search of active cells around point more
  // efficient
  std::vector<bool> marked_vertices(triangulation.n_vertices(), false);
 
  for(auto const & cell : triangulation.active_cell_iterators())
  {
    if(not(cell->is_artificial()) and cell->at_boundary())
    {
      for(auto const & f : cell->face_indices())
      {
        if(cell->face(f)->at_boundary())
        {
          if(boundary_ids.find(cell->face(f)->boundary_id()) != boundary_ids.end())
          {
            for(auto const & v : cell->face(f)->vertex_indices())
            {
              marked_vertices[cell->face(f)->vertex_index(v)] = true;
            }
          }
        }
      }
    }
  }
 
  // To improve robustness, make sure that not all entries of marked_vertices are false.
  // If no useful information about marked vertices can be provided, an empty vector should
  // be used.
  if(std::all_of(marked_vertices.begin(), marked_vertices.end(), [](bool vertex_is_marked) {
       return vertex_is_marked == false;
     }))
  {
    marked_vertices.clear();
  }
 
  return marked_vertices;
}
 
#endif /* EXADG_GRID_MARKED_VERTICES_H_ */