fe_collection.h

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// -----------------------------------------------------------------------------
//
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception OR LGPL-2.1-or-later
// Copyright (C) 2005 - 2025 by the deal.II authors
//
// This file is part of the deal.II library.
//
// Detailed license information governing the source code and contributions
// can be found in LICENSE.md and CONTRIBUTING.md at the top level directory.
//
// -----------------------------------------------------------------------------
 
#ifndef dealii_fe_collection_h
#define dealii_fe_collection_h
 
#include <deal.II/base/config.h>
 
#include <deal.II/fe/component_mask.h>
#include <deal.II/fe/fe.h>
#include <deal.II/fe/fe_values_extractors.h>
 
#include <deal.II/hp/collection.h>
 
#include <memory>
#include <set>
 
 
DEAL_II_NAMESPACE_OPEN
 
// Forward declarations
namespace hp
{
  template <int dim, int spacedim>
  class MappingCollection;
}
 
 
namespace hp
{
  template <int dim, int spacedim = dim>
  class FECollection : public Collection<FiniteElement<dim, spacedim>>
  {
  public:
    struct DefaultHierarchy
    {
      static unsigned int
      next_index(const typename hp::FECollection<dim, spacedim> &fe_collection,
                 const unsigned int                              fe_index)
      {
        return ((fe_index + 1) < fe_collection.size()) ? fe_index + 1 :
                                                         fe_index;
      }
 
      static unsigned int
      previous_index(
        const typename hp::FECollection<dim, spacedim> &fe_collection,
        const unsigned int                              fe_index)
      {
        (void)fe_collection;
        return (fe_index > 0) ? fe_index - 1 : fe_index;
      }
    };
 
    FECollection();
 
    explicit FECollection(const FiniteElement<dim, spacedim> &fe);
 
    template <class... FETypes>
    explicit FECollection(const FETypes &...fes);
 
    FECollection(const std::vector<const FiniteElement<dim, spacedim> *> &fes);
 
    FECollection(const FECollection<dim, spacedim> &) = default;
 
    FECollection(FECollection<dim, spacedim> &&) noexcept(
      std::is_nothrow_move_constructible_v<
        std::vector<std::shared_ptr<const FiniteElement<dim, spacedim>>>>
        &&std::is_nothrow_move_constructible_v<std::function<
          unsigned int(const typename hp::FECollection<dim, spacedim> &,
                       const unsigned int)>>) = default;
 
    FECollection<dim, spacedim> &
    operator=(FECollection<dim, spacedim> &&) = default; // NOLINT
 
    bool
    operator==(const FECollection<dim, spacedim> &fe_collection) const;
 
    bool
    operator!=(const FECollection<dim, spacedim> &fe_collection) const;
 
    void
    push_back(const FiniteElement<dim, spacedim> &new_fe);
 
    unsigned int
    n_components() const;
 
    unsigned int
    n_blocks() const;
 
    unsigned int
    max_degree() const;
 
    unsigned int
    max_dofs_per_vertex() const;
 
    unsigned int
    max_dofs_per_line() const;
 
    unsigned int
    max_dofs_per_quad() const;
 
    unsigned int
    max_dofs_per_hex() const;
 
    unsigned int
    max_dofs_per_face() const;
 
    unsigned int
    max_dofs_per_cell() const;
 
    const MappingCollection<dim, spacedim> &
    get_reference_cell_default_linear_mapping() const;
 
    bool
    hp_constraints_are_implemented() const;
 
    std::vector<std::map<unsigned int, unsigned int>>
    hp_vertex_dof_identities(const std::set<unsigned int> &fes) const;
 
    std::vector<std::map<unsigned int, unsigned int>>
    hp_line_dof_identities(const std::set<unsigned int> &fes) const;
 
    std::vector<std::map<unsigned int, unsigned int>>
    hp_quad_dof_identities(const std::set<std::pair<unsigned int, unsigned int>>
                             &fes_and_faces) const;
 
    std::set<unsigned int>
    find_common_fes(const std::set<unsigned int> &fes,
                    const unsigned int            codim = 0) const;
 
    std::set<unsigned int>
    find_enclosing_fes(const std::set<unsigned int> &fes,
                       const unsigned int            codim = 0) const;
 
    unsigned int
    find_dominating_fe(const std::set<unsigned int> &fes,
                       const unsigned int            codim = 0) const;
 
    unsigned int
    find_dominated_fe(const std::set<unsigned int> &fes,
                      const unsigned int            codim = 0) const;
 
    unsigned int
    find_dominating_fe_extended(const std::set<unsigned int> &fes,
                                const unsigned int            codim = 0) const;
 
    unsigned int
    find_dominated_fe_extended(const std::set<unsigned int> &fes,
                               const unsigned int            codim = 0) const;
 
    void
    set_hierarchy(const std::function<unsigned int(
                    const typename hp::FECollection<dim, spacedim> &,
                    const unsigned int)> &next,
                  const std::function<unsigned int(
                    const typename hp::FECollection<dim, spacedim> &,
                    const unsigned int)> &prev);
 
    void
    set_default_hierarchy();
 
    std::vector<unsigned int>
    get_hierarchy_sequence(const unsigned int fe_index = 0) const;
 
    unsigned int
    next_in_hierarchy(const unsigned int fe_index) const;
 
    unsigned int
    previous_in_hierarchy(const unsigned int fe_index) const;
 
    ComponentMask
    component_mask(const FEValuesExtractors::Scalar &scalar) const;
 
    ComponentMask
    component_mask(const FEValuesExtractors::Vector &vector) const;
 
    ComponentMask
    component_mask(
      const FEValuesExtractors::SymmetricTensor<2> &sym_tensor) const;
 
    ComponentMask
    component_mask(const BlockMask &block_mask) const;
 
    BlockMask
    block_mask(const FEValuesExtractors::Scalar &scalar) const;
 
    BlockMask
    block_mask(const FEValuesExtractors::Vector &vector) const;
 
    BlockMask
    block_mask(const FEValuesExtractors::SymmetricTensor<2> &sym_tensor) const;
 
    BlockMask
    block_mask(const ComponentMask &component_mask) const;
 
    DeclException0(ExcNoFiniteElements);
 
  private:
    std::shared_ptr<MappingCollection<dim, spacedim>>
      reference_cell_default_linear_mapping;
 
    std::function<unsigned int(const typename hp::FECollection<dim, spacedim> &,
                               const unsigned int)>
      hierarchy_next;
 
    std::function<unsigned int(const typename hp::FECollection<dim, spacedim> &,
                               const unsigned int)>
      hierarchy_prev;
  };
 
 
 
  /* --------------- inline functions ------------------- */
 
  template <int dim, int spacedim>
  template <class... FETypes>
  FECollection<dim, spacedim>::FECollection(const FETypes &...fes)
  {
    static_assert(
      is_base_of_all<FiniteElement<dim, spacedim>, FETypes...>::value,
      "Not all of the input arguments of this function "
      "are derived from FiniteElement<dim, spacedim>!");
 
    // loop over all of the given arguments and add the finite elements to
    // this collection. Inlining the definition of fe_pointers causes internal
    // compiler errors on GCC 7.1.1 so we define it separately:
    const auto fe_pointers = {
      (static_cast<const FiniteElement<dim, spacedim> *>(&fes))...};
    for (const auto p : fe_pointers)
      push_back(*p);
  }
 
 
 
  template <int dim, int spacedim>
  inline unsigned int
  FECollection<dim, spacedim>::n_components() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    // note that there is no need
    // here to enforce that indeed
    // all elements have the same
    // number of components since we
    // have already done this when
    // adding a new element to the
    // collection.
 
    return this->operator[](0).n_components();
  }
 
 
 
  template <int dim, int spacedim>
  inline bool
  FECollection<dim, spacedim>::operator==(
    const FECollection<dim, spacedim> &fe_collection) const
  {
    const unsigned int n_elements = this->size();
    if (n_elements != fe_collection.size())
      return false;
 
    for (unsigned int i = 0; i < n_elements; ++i)
      if (!(this->operator[](i) == fe_collection[i]))
        return false;
 
    return true;
  }
 
 
 
  template <int dim, int spacedim>
  inline bool
  FECollection<dim, spacedim>::operator!=(
    const FECollection<dim, spacedim> &fe_collection) const
  {
    return !(*this == fe_collection);
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_degree() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).degree);
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_vertex() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).n_dofs_per_vertex());
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_line() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).n_dofs_per_line());
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_quad() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).max_dofs_per_quad());
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_hex() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).n_dofs_per_hex());
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_face() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).max_dofs_per_face());
 
    return max;
  }
 
 
 
  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_cell() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    unsigned int max = 0;
    for (unsigned int i = 0; i < this->size(); ++i)
      max = std::max(max, this->operator[](i).n_dofs_per_cell());
 
    return max;
  }
 
 
  template <int dim, int spacedim>
  bool
  FECollection<dim, spacedim>::hp_constraints_are_implemented() const
  {
    Assert(this->size() > 0, ExcNoFiniteElements());
 
    for (unsigned int i = 0; i < this->size(); ++i)
      if (this->operator[](i).hp_constraints_are_implemented() == false)
        return false;
 
    return true;
  }
 
 
} // namespace hp
 
DEAL_II_NAMESPACE_CLOSE
 
#endif