lagrangedgbasis.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
 
// SPDX-FileCopyrightText: Copyright © DUNE Project contributors, see file AUTHORS.md
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception OR LGPL-3.0-or-later
 
#ifndef DUNE_FUNCTIONS_FUNCTIONSPACEBASES_LAGRANGEDGBASIS_HH
#define DUNE_FUNCTIONS_FUNCTIONSPACEBASES_LAGRANGEDGBASIS_HH
 
#include <dune/common/exceptions.hh>
#include <dune/common/math.hh>
 
#include <dune/functions/functionspacebases/nodes.hh>
#include <dune/functions/functionspacebases/defaultglobalbasis.hh>
#include <dune/functions/functionspacebases/lagrangebasis.hh>
#include <dune/functions/functionspacebases/leafprebasismappermixin.hh>
 
 
 
 
namespace Dune {
namespace Functions {
 
 
 
// *****************************************************************************
// This is the reusable part of the basis. It contains
//
//   LagrangeDGPreBasis
//   LagrangeDGNode
//
// The pre-basis allows to create the others and is the owner of possible shared
// state. These components do _not_ depend on the global basis and local view
// and can be used without a global basis.
// *****************************************************************************
 
template<typename GV, int k, typename R=double>
using LagrangeDGNode = LagrangeNode<GV, k, R>;
 
template<typename GV, int k, typename R=double>
class LagrangeDGPreBasis :
  public Dune::Functions::LeafPreBasisMapperMixin<GV>
{
  using Base = Dune::Functions::LeafPreBasisMapperMixin<GV>;
 
  static constexpr bool useDynamicOrder = (k<0);
 
  static MCMGLayout dofLayout(int order)
  {
    return [order](Dune::GeometryType type, size_t dimGrid) {
      if (type.dim() == dimGrid)
      {
        if (type.isLine())
          return order+1;
        if (type.isTriangle())
          return (order+1)*(order+2)/2;
        if (type.isQuadrilateral())
          return (order+1)*(order+1);
        if (type.isTetrahedron())
          return (order+1)*(order+2)*(order+3)/6;
        if (type.isPrism())
          return (order+1)*(order+1)*(order+2)/2;
        if (type.isHexahedron())
          return (order+1)*(order+1)*(order+1);
        if (type.isPyramid())
          return (order+1)*(order+2)*(2*order+3)/6;
        DUNE_THROW(Dune::NotImplemented, "Using LagrangeDGPreBasis with non-supported GeometryType");
      }
      return 0;
    };
  }
 
public:
 
  using GridView = GV;
  using size_type = typename Base::size_type;
  using Node = LagrangeDGNode<GV, k, R>;
 
  LagrangeDGPreBasis(const GridView& gv)
    requires(k>=0)
    : Base(gv, dofLayout(k))
    , order_(k)
  {}
 
  LagrangeDGPreBasis(const GridView& gv, unsigned int order)
    requires(k<0)
    : Base(gv, dofLayout(order))
    , order_(order)
  {}
 
  Node makeNode() const
  {
    return Node{order_};
  }
 
  template<class Node, class It>
  It indices(const Node& node, It it) const
  {
    size_type elementOffset = Base::mapper_.index(node.element());
    for(auto i : Dune::range(node.size()))
    {
      *it = {{ (size_type)(elementOffset+i) }};
      ++it;
    }
    return it;
  }
 
  unsigned int order() const
  {
    return (useDynamicOrder) ? order_ : k;
  }
 
protected:
 
  unsigned int order_;
};
 
 
 
namespace BasisFactory {
 
template<std::size_t order, typename R=double>
auto lagrangeDG()
{
  return [](const auto& gridView) {
    return LagrangeDGPreBasis<std::decay_t<decltype(gridView)>, order, R>(gridView);
  };
}
 
template<typename R=double>
auto lagrangeDG(unsigned int order)
{
  return [order](const auto& gridView) {
    return LagrangeDGPreBasis<std::decay_t<decltype(gridView)>, -1, R>(gridView, order);
  };
}
 
} // end namespace BasisFactory
 
 
 
// *****************************************************************************
// This is the actual global basis implementation based on the reusable parts.
// *****************************************************************************
 
template<typename GV, int k=-1, typename R=double>
using LagrangeDGBasis = DefaultGlobalBasis<LagrangeDGPreBasis<GV, k, R> >;
 
 
 
} // end namespace Functions
} // end namespace Dune
 
 
#endif // DUNE_FUNCTIONS_FUNCTIONSPACEBASES_LAGRANGEDGBASIS_HH