defaultnodetorangemap.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTNODETORANGEMAP_HH
#define DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTNODETORANGEMAP_HH
 
 
#include <dune/common/concept.hh>
 
#include <dune/functions/functionspacebases/concepts.hh>
 
#include <dune/typetree/traversal.hh>
#include <dune/typetree/visitor.hh>
 
 
namespace Dune {
namespace Functions {
 
 
 
template<class Tree>
struct DefaultNodeToRangeMap
{
 
  // A simple visitor for computing lexicographic
  // subtree indices. To identify a leaf node
  // we use its treeIndex() which is unique
  // wrt the whole tree and store the computed
  // index in a vector indexed by the tree indices.
  struct Visitor
    : public TypeTree::TreeVisitor
    , public TypeTree::DynamicTraversal
  {
    Visitor(std::vector<std::size_t>& indices) :
      indices_(indices),
      counter_(0)
    {}
 
    template<typename Node, typename TreePath>
    void leaf(Node& node, TreePath treePath)
    {
      if (indices_.size() < node.treeIndex()+1)
        indices_.resize(node.treeIndex()+1);
      indices_[node.treeIndex()] = counter_;
      ++counter_;
    }
 
    std::vector<std::size_t>& indices_;
    std::size_t counter_;
  };
 
  DefaultNodeToRangeMap(const Tree& tree)
  {
    TypeTree::applyToTree(tree, Visitor(indices_));
  }
 
  template<class Node, class TreePath, class Range,
    std::enable_if_t<models<Concept::HasIndexAccess, Range, decltype(std::declval<Node>().treeIndex())>() and not Tree::isLeaf, int> = 0>
  decltype(auto) operator()(const Node& node, const TreePath& treePath, Range&& y) const
  {
    return y[indices_[node.treeIndex()]];
  }
 
  template<class Node, class TreePath, class Range,
    std::enable_if_t< not models<Concept::HasIndexAccess, Range, decltype(std::declval<Node>().treeIndex())>() or Tree::isLeaf, int> = 0>
  decltype(auto) operator()(const Node& node, const TreePath& treePath, Range&& y) const
  {
    return std::forward<Range>(y);
  }
 
  std::vector<std::size_t> indices_;
};
 
 
 
template<class Tree>
DefaultNodeToRangeMap<Tree> makeDefaultNodeToRangeMap(const Tree& tree)
{
  return DefaultNodeToRangeMap<Tree>(tree);
}
 
 
 
template<class Basis, class TreePath>
auto makeDefaultNodeToRangeMap(const Basis& basis, TreePath&& treePath)
  -> decltype(makeDefaultNodeToRangeMap(TypeTree::child(basis.localView().tree(),treePath)))
{
  auto&& localView = basis.localView();
  localView.bind(*basis.gridView().template begin<0>());
  auto&& tree = TypeTree::child(localView.tree(),treePath);
  return makeDefaultNodeToRangeMap(tree);
}
 
 
 
} // namespace Dune::Functions
} // namespace Dune
 
 
#endif // DUNE_FUNCTIONS_FUNCTIONSPACEBASES_DEFAULTNODETORANGEMAP_HH