cell_geometry.hh

Go to the documentation of this file.

#pragma once
 
// external libraries
#include <deal.II/dofs/dof_handler.h>
 
// standard library
#include <cmath>
#include <limits>
#include <stdexcept>
 
namespace DiFfRG
{
  namespace internal
  {
    template <typename CellIterator> double face_normal_cell_width(const CellIterator &cell, const uint face_no)
    {
      const double face_measure = cell->face(face_no)->measure();
      if (!(face_measure > 0.) || !std::isfinite(face_measure))
        throw std::runtime_error("face_normal_cell_width: invalid face measure.");
 
      const double width = cell->measure() / face_measure;
      if (!(width > 0.) || !std::isfinite(width))
        throw std::runtime_error("face_normal_cell_width: invalid face-normal cell width.");
      return width;
    }
 
    template <typename CellIterator> double cell_width(const CellIterator &cell)
    {
      double width = std::numeric_limits<double>::max();
      for (uint face_no = 0; face_no < cell->n_faces(); ++face_no)
        width = std::min(width, face_normal_cell_width(cell, face_no));
      return width;
    }
 
    template <int dim> double minimum_face_normal_cell_width(const dealii::DoFHandler<dim> &dof_handler)
    {
      double minimum_width = std::numeric_limits<double>::max();
      for (const auto &cell : dof_handler.active_cell_iterators())
        minimum_width = std::min(minimum_width, cell_width(cell));
 
      if (!(minimum_width < std::numeric_limits<double>::max()))
        throw std::runtime_error("minimum_face_normal_cell_width: the mesh has no active cells.");
      return minimum_width;
    }
  } // namespace internal
} // namespace DiFfRG