fe_collection.h

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// ---------------------------------------------------------------------
//
// Copyright (C) 2003 - 2020 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_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 <memory>

DEAL_II_NAMESPACE_OPEN

namespace hp
{
  template <int dim, int spacedim = dim>
  class FECollection : public Subscriptor
  {
  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<
        std::vector<std::shared_ptr<const FiniteElement<dim, spacedim>>>>::value
        &&std::is_nothrow_move_constructible<std::function<
          unsigned int(const typename hp::FECollection<dim, spacedim> &,
                       const unsigned int)>>::value) = 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);

    const FiniteElement<dim, spacedim> &
    operator[](const unsigned int index) const;

    unsigned int
    size() const;

    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;

    std::size_t
    memory_consumption() const;


    bool
    hp_constraints_are_implemented() const;

    DEAL_II_DEPRECATED unsigned int
    find_least_face_dominating_fe(const std::set<unsigned int> &fes) 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();

    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);

    DeclExceptionMsg(
      ExcNoDominatedFiniteElementAmongstChildren,
      "No FiniteElement has been found in your FECollection that is "
      "dominated by all children of a cell you are trying to coarsen!");

  private:
    std::vector<std::shared_ptr<const FiniteElement<dim, spacedim>>>
      finite_elements;

    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>::size() const
  {
    return finite_elements.size();
  }


  template <int dim, int spacedim>
  inline unsigned int
  FECollection<dim, spacedim>::n_components() const
  {
    Assert(finite_elements.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 finite_elements[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 = size();
    if (n_elements != fe_collection.size())
      return false;

    for (unsigned int i = 0; i < n_elements; ++i)
      if (!(*finite_elements[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>
  inline const FiniteElement<dim, spacedim> &FECollection<dim, spacedim>::
                                             operator[](const unsigned int index) const
  {
    AssertIndexRange(index, finite_elements.size());
    return *finite_elements[index];
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_degree() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      max = std::max(max, finite_elements[i]->degree);

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_vertex() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_vertex > max)
        max = finite_elements[i]->dofs_per_vertex;

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_line() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_line > max)
        max = finite_elements[i]->dofs_per_line;

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_quad() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_quad > max)
        max = finite_elements[i]->dofs_per_quad;

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_hex() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_hex > max)
        max = finite_elements[i]->dofs_per_hex;

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_face() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_face > max)
        max = finite_elements[i]->dofs_per_face;

    return max;
  }



  template <int dim, int spacedim>
  unsigned int
  FECollection<dim, spacedim>::max_dofs_per_cell() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());

    unsigned int max = 0;
    for (unsigned int i = 0; i < finite_elements.size(); ++i)
      if (finite_elements[i]->dofs_per_cell > max)
        max = finite_elements[i]->dofs_per_cell;

    return max;
  }


  template <int dim, int spacedim>
  bool
  FECollection<dim, spacedim>::hp_constraints_are_implemented() const
  {
    Assert(finite_elements.size() > 0, ExcNoFiniteElements());
    return std::all_of(
      finite_elements.cbegin(),
      finite_elements.cend(),
      [](const std::shared_ptr<const FiniteElement<dim, spacedim>> &fe) {
        return fe->hp_constraints_are_implemented();
      });
  }


} // namespace hp

DEAL_II_NAMESPACE_CLOSE

#endif