defaultlocalview.hh

// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTLOCALVIEW_HH
#define DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTLOCALVIEW_HH
 
 
#include <tuple>
 
#include <dune/common/concept.hh>
#include <dune/common/std/optional.hh>
#include <dune/common/hybridutilities.hh>
 
#include <dune/functions/functionspacebases/concepts.hh>
 
 
 
namespace Dune {
namespace Functions {
 
 
 
template<class GB>
class DefaultLocalView
{
  // Node index set provided by PreBasis
  using NodeIndexSet = typename GB::PreBasis::IndexSet;
 
public:
 
  using GlobalBasis = GB;
 
  using GridView = typename GlobalBasis::GridView;
 
  using Element = typename GridView::template Codim<0>::Entity;
 
  using size_type = std::size_t;
 
  using Tree = typename GlobalBasis::PreBasis::Node;
 
  using MultiIndex = typename NodeIndexSet::MultiIndex;
 
private:
 
  template<typename NodeIndexSet_>
  using hasIndices = decltype(std::declval<NodeIndexSet_>().indices(std::declval<std::vector<typename NodeIndexSet_::MultiIndex>>().begin()));
 
public:
 
  DefaultLocalView(const GlobalBasis& globalBasis) :
    globalBasis_(&globalBasis),
    tree_(globalBasis_->preBasis().makeNode()),
    nodeIndexSet_(globalBasis_->preBasis().makeIndexSet())
  {
    static_assert(models<Concept::BasisTree<GridView>, Tree>(), "Tree type passed to DefaultLocalView does not model the BasisNode concept.");
    initializeTree(tree_);
  }
 
  void bind(const Element& e)
  {
    element_ = e;
    bindTree(tree_, *element_);
    nodeIndexSet_.bind(tree_);
    indices_.resize(size());
    Hybrid::ifElse(
      Std::is_detected<hasIndices,NodeIndexSet>{},
      [&](auto id) {
        id(nodeIndexSet_).indices(indices_.begin());
      },
      [&](auto id) {
        for (size_type i = 0 ; i < this->size() ; ++i)
          indices_[i] = id(nodeIndexSet_).index(i);
      });
  }
 
  bool isBound() const {
    return static_cast<bool>(element_);
  }
 
  const Element& element() const
  {
    return *element_;
  }
 
  void unbind()
  {
    nodeIndexSet_.unbind();
    element_.reset();
  }
 
  const Tree& tree() const
  {
    return tree_;
  }
 
  size_type size() const
  {
    return tree_.size();
  }
 
  size_type maxSize() const
  {
    return globalBasis_->preBasis().maxNodeSize();
  }
 
  MultiIndex index(size_type i) const
  {
    return indices_[i];
  }
 
  const GlobalBasis& globalBasis() const
  {
    return *globalBasis_;
  }
 
  const DefaultLocalView& rootLocalView() const
  {
    return *this;
  }
 
protected:
  const GlobalBasis* globalBasis_;
  Std::optional<Element> element_;
  Tree tree_;
  NodeIndexSet nodeIndexSet_;
  std::vector<MultiIndex> indices_;
};
 
 
 
} // end namespace Functions
} // end namespace Dune
 
 
 
#endif // DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTLOCALVIEW_HH