fe_q_base.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2000 - 2018 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
// ---------------------------------------------------------------------

#ifndef dealii_fe_q_base_h
#define dealii_fe_q_base_h

#include <deal.II/base/config.h>

#include <deal.II/base/thread_management.h>

#include <deal.II/fe/fe_poly.h>

DEAL_II_NAMESPACE_OPEN



template <class PolynomialType,
          int dim      = PolynomialType::dimension,
          int spacedim = dim>
class FE_Q_Base : public FE_Poly<PolynomialType, dim, spacedim>
{
public:
  FE_Q_Base(const PolynomialType &        poly_space,
            const FiniteElementData<dim> &fe_data,
            const std::vector<bool> &     restriction_is_additive_flags);

  virtual void
  get_interpolation_matrix(const FiniteElement<dim, spacedim> &source,
                           FullMatrix<double> &matrix) const override;


  virtual void
  get_face_interpolation_matrix(const FiniteElement<dim, spacedim> &source,
                                FullMatrix<double> &matrix) const override;

  virtual void
  get_subface_interpolation_matrix(const FiniteElement<dim, spacedim> &source,
                                   const unsigned int                  subface,
                                   FullMatrix<double> &matrix) const override;

  virtual bool
  has_support_on_face(const unsigned int shape_index,
                      const unsigned int face_index) const override;

  virtual const FullMatrix<double> &
  get_restriction_matrix(
    const unsigned int         child,
    const RefinementCase<dim> &refinement_case =
      RefinementCase<dim>::isotropic_refinement) const override;

  virtual const FullMatrix<double> &
  get_prolongation_matrix(
    const unsigned int         child,
    const RefinementCase<dim> &refinement_case =
      RefinementCase<dim>::isotropic_refinement) const override;

  virtual unsigned int
  face_to_cell_index(const unsigned int face_dof_index,
                     const unsigned int face,
                     const bool         face_orientation = true,
                     const bool         face_flip        = false,
                     const bool         face_rotation = false) const override;

  virtual std::pair<Table<2, bool>, std::vector<unsigned int>>
  get_constant_modes() const override;

  virtual bool
  hp_constraints_are_implemented() const override;

  virtual std::vector<std::pair<unsigned int, unsigned int>>
  hp_vertex_dof_identities(
    const FiniteElement<dim, spacedim> &fe_other) const override;

  virtual std::vector<std::pair<unsigned int, unsigned int>>
  hp_line_dof_identities(
    const FiniteElement<dim, spacedim> &fe_other) const override;

  virtual std::vector<std::pair<unsigned int, unsigned int>>
  hp_quad_dof_identities(
    const FiniteElement<dim, spacedim> &fe_other) const override;


  DeclExceptionMsg(ExcFEQCannotHaveDegree0,
                   "FE_Q can only be used for polynomial degrees "
                   "greater than zero. If you want an element of polynomial "
                   "degree zero, then it cannot be continuous and you "
                   "will want to use FE_DGQ<dim>(0).");

protected:
  static std::vector<unsigned int>
  get_dpo_vector(const unsigned int degree);

  void
  initialize(const std::vector<Point<1>> &support_points_1d);

  void
  initialize_constraints(const std::vector<Point<1>> &points);

  void
  initialize_unit_support_points(const std::vector<Point<1>> &points);

  void
  initialize_unit_face_support_points(const std::vector<Point<1>> &points);

  void
  initialize_quad_dof_index_permutation();

  struct Implementation;

  /*
   * Declare implementation friend.
   */
  friend struct FE_Q_Base<PolynomialType, dim, spacedim>::Implementation;

private:
  /*
   * Mutex for protecting initialization of restriction and embedding matrix.
   */
  mutable Threads::Mutex mutex;

  /*
   * The highest polynomial degree of the underlying tensor product space
   * without any enrichment. For FE_Q*(p) this is p. Note that enrichments
   * may lead to a difference to degree.
   */
  const unsigned int q_degree;
};


DEAL_II_NAMESPACE_CLOSE

#endif