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// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_GRID_COMMON_RANGEGENERATORS_HH
#define DUNE_GRID_COMMON_RANGEGENERATORS_HH
#include <dune/common/iteratorrange.hh>
#include <dune/geometry/dimension.hh>
#include <dune/grid/common/gridenums.hh>
#include <dune/grid/common/partitionset.hh>
namespace Dune
{
#ifdef DOXYGEN
/**
* \addtogroup GIIteration
* \brief Iterator ranges for entities and intersections to support iteration with range-based for loops.
*
* Iterating over sets of entities or intersections is one of the most common operations when
* writing DUNE code. The grid interface implements this in the standard C++ ways by providing
* iterators and matching begin() and end() methods, but their usage can be rather unwieldy.
*
* This page describes a much simpler alternative based on a C++11 feature called range-based for loop.
*
* <h2>Range-based for loop</h2>
*
* A range-based for loop is a short-hand way of iterating over any object that provides the standard
* begin() and end() methods. It looks like this:
*
* \code
* for (const auto& i : vec)
* i *= 2;
* \endcode
*
* This code will multiply all entries of `vec` by 2. The loop head always looks like `for (<type> <variable-name> : <container>)`.
* You can also specify the exact type of the variable, but it is normally much easier to let the compiler
* do that for you using `auto`.
*
* \note We are aware that people like Bjarne Stroustrup and Herb
* Sutter advertise the use `auto&&`. Sadly GCC prior to version 6 has a bug (see
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63506), which
* prevents the use of `auto&&` in template functions. For this reason
* we currently advice the use of `const auto&`.
*
* For those interested in the technical details, the compiler has translated the loop into
* something resembling this (not quite, but we'll forget about the minor details here):
*
* \code
* for (auto it = vec.begin(),
* end = vec.end();
* it != end;
* ++it)
* {
* const auto& i = *it;
* i *= 2;
* }
* \endcode
*
* For further details, see e.g. http://en.cppreference.com/w/cpp/language/range-for.
*
* <h2>Entities</h2>
*
* You cannot simply iterate over all entities of a GridView by passing it to a range-based for loop,
* simply because you cannot (and probably do not want to) iterator over *all* of its entities. Instead,
* algorithms typically have to iterate over all entities with a particular codimension, e.g. over all
* grid cells. The functions listed at the top of this page allow you to do just this. Assuming you have
* a GridView `gv`, you can iterate over its cells and vertices like this:
*
* \code
* // iterate over cells
* for (const auto& cell : elements(gv))
* {
* std::cout << "Cell " << gv.indexSet().index(cell) << " is centered at "
* << cell.geometry().center() << std::endl;
* }
* // iterate over vertices
* for (const auto& vertex : vertices(gv))
* {
* std::cout << "Vertex " << gv.indexSet().index(vertex) << " at "
* << vertex.geometry().center() << std::endl;
* }
* \endcode
*
* \note As explained above, **always** use `const auto&` for the type of the Entity!
*
* There are also functions for iterating over facets() and edges() as well as generic entities() functions,
* which allow you to specify a numeric codimension or dimension.
*
* If you are using Dune for parallel computations, you probably know that the GridView offers iterators with
* different \link PartitionIteratorType PartitionIteratorTypes\endlink. Those are also supported with range-based
* for loops: By default, the functions above will iterate over all entities (Dune::All_Partition), but they
* accept an additional parameter for selecting a different set of partitions. This parameter is of type
* Dune::PartitionSet. You can find pre-instantiated objects for all partitions and allowed combinations in the
* namespace Dune::Partitions. Using those objects, you can iterate over all interior and border vertices like
* this:
*
* \code
* // use prebuild PartitionSet
* for (const auto& vertex : vertices(gv,Dune::Partitions::interiorBorder))
* {
* ...
* }
* // construct PartitionSet by combining partitions
* for (const auto& vertex : vertices(gv,Dune::Partitions::interior + Dune::Partitions::border))
* {
* ...
* }
* \endcode
*
* <h2>Intersections</h2>
*
* If you want to iterate over the \link Intersection intersections \endlink of an Entity, you can
* use the function intersections() to obtain a range that is suitable for a range-based for loop.
* Intersections are always defined with respect to a GridView; for further information, see the discussion
* on locally refined grids.
*
* As an example, the following code counts the number of boundary intersections for a given GridView `gv`:
*
* \code
* std::size_t count = 0;
* for (const auto& e : elements(gv))
* {
* do_stuff();
* for (const auto& i : intersections(gv,e))
* {
* if (e.boundary())
* ++count;
* }
* }
* \endcode
*
* <h1>Information for grid implementors</h1>
*
* <h2>Custom range implementations</h2>
*
* The default implementation of the range generator functions calls the correct begin() and end()
* methods on the GridView / the Entity and stores the iterators returned by these methods in an
* IteratorRange object which is then returned by value (as a temporary object). While any overhead
* associated with this process will normally be negligible compared with the ensuing grid traversal,
* you can guarantee optimal performance by making sure that your iterators are move-constructible and
* move-assignable.
* If, for some reason, you don't want to rely on this default implementation, you only have to provide
* an overload for the function `entities(const GV&, Dune::Codim<cd>, Dune::PartitionSet<ps>)`. All
* other functions simply forward to this single function. Apart from that, you will of course have
* to overload `intersections()` and `descendantElements()` as well - those are entirely separate.
*
* <h2>ADL lookup for grids in non-standard namespaces</h2>
*
* The range generator functions described on this page are found by means of argument-dependent
* lookup (ADL). That way, users don't have to explicitly specify the namespace when using those
* functions.
*
* Making ADL work does however require some care from grid implementors who are developing grids
* which are not placed in the namespace `Dune`. More precisely, the GridView and the Entity classes
* have to be in that namespace. If you are using the default facade classes, you don't have to worry
* about this fact (the facade classes are in the correct namespace), but if your implementation
* does not use those facades, you will have to import the functions on this page into the namespace
* of your GridView and / or Entity classes to make ADL work:
*
* \code
* namespace MyAweSomeGrid {
*
* using Dune::entities;
* using Dune::elements;
* using Dune::facets;
* using Dune::edges;
* using Dune::vertices;
* using Dune::descendantElements;
* using Dune::intersections;
*
* ...
*
* }
* \endcode
*
* Of course, you can also reimplement all functions in your own namespace, but that's probably
* a bad idea...
*
* \{
*/
// *****************************************************************************************
// Doxygen documentation
// *****************************************************************************************
//
// In the following, the range generating functions are documented for Doxygen; the actual
// implementations are further down in this file and hidden from Doxygen.
// The main reason for this split are the return types of those functions, which either contain
// long type listings to obtain the iterator type or (in the case of the forwarded functions
// use the new-style function syntax and calculate the return type using decltype. In both cases,
// Doxygen generates function signatures that are very confusing to the average user.
//
// *****************************************************************************************
//! \name Common entity ranges
//! \brief Entity ranges for common entity types. If in doubt, use one of these.
//! \{
//! Iterates over all elements / cells (entities with codimension 0) of a GridView.
/**
* This functions returns an object representing the range of *elements* or *cells*
* contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all cells in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : elements(gv))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This is the default version of the elements() function. It will always iterate over all
* elements in the GridView, regardless of their Dune::PartitionType. If you are interested
* in cells with specific PartitionType(s), use elements(const GV&,PartitionSet<partitions>)
* instead.
*
* \sa elements(const GV&,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the elements.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV>
inline IteratorRange<...> elements(const GV& gv);
//! Iterates over all facets (entities with codimension 1) of a GridView.
/**
* This functions returns an object representing the range of *facets*
* contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all facets in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : facets(gv))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This is the default version of the facets() function. It will always iterate over all
* elements in the GridView, regardless of their Dune::PartitionType. If you are interested
* in cells with specific PartitionType(s), use facets(const GV&,PartitionSet<partitions>)
* instead.
*
* \sa facets(const GV&,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the facets.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV>
inline IteratorRange<...> facets(const GV& gv);
//! Iterates over all edges (entities with dimension 1) of a GridView.
/**
* This functions returns an object representing the range of *edges*
* contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all edges in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : edges(gv))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This is the default version of the edges() function. It will always iterate over all
* elements in the GridView, regardless of their Dune::PartitionType. If you are interested
* in cells with specific PartitionType(s), use edges(const GV&,PartitionSet<partitions>)
* instead.
*
* \sa edges(const GV&,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the edges.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV>
inline IteratorRange<...> edges(const GV& gv);
//! Iterates over all vertices (entities with dimension 0) of a GridView.
/**
* This functions returns an object representing the range of *vertices*
* contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all vertices in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : vertices(gv))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This is the default version of the vertices() function. It will always iterate over all
* elements in the GridView, regardless of their Dune::PartitionType. If you are interested
* in cells with specific PartitionType(s), use vertices(const GV&,PartitionSet<partitions>)
* instead.
*
* \sa vertices(const GV&,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the vertices.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV>
inline IteratorRange<...> vertices(const GV& gv);
//! \}
//! \name Intersection Range
//! \brief Iterator range for \link Intersection intersections \endlink.
//! \{
//! Iterates over all \link Intersection Intersections \endlink of an Entity with respect to the given GridView.
/**
* This functions returns an object representing the range of `Intersection`s of the Entity
* e with respect to the GridView gv. The main purpose of this function is to enable
* iteration over those intersections by means of a range-based for loop:
*
* \code
* // iterate over all intersections of an entity with respect to the LeafGridView
* auto gv = grid.leafGridView();
* const auto& entity = ...; // get an entity from somewhere
* for (const auto& i : intersections(gv,entity))
* {
* std::cout << i.geometry().center() << std::endl;
* }
* \endcode
*
* \relates GridView
* \relates Entity
* \param gv the GridView to use for determining interior intesections.
* \param e the Entity whose intersections should be iterated over.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, typename Entity>
inline IteratorRange<...> intersections(const GV& gv, const Entity& e);
//! \}
//! \name Hierarchic Entity range
//! \brief Iterator range for hierarchic access to the more-refined entities that result from the subdivision of a given element.
//! \{
//! Iterates over all descendant elements of the given element up to a maximum level.
/**
* This functions returns an object representing the range of descendat elements of the
* element (Entity with codimension 0) e. The main purpose of this function is to enable
* iteration over those descendants by means of a range-based for loop:
*
* \code
* // iterate over all descendants of an entity
* const auto& entity = ...; // get an entity from somewhere
* for (const auto& e : descendantElements(entity,grid.maxLevel()))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \note This function only works for elements (entities with codimension 0). Attempting to
* call this function with an entity of higher codimension will result in a compile
* time error.
*
* \relates Entity
* \param e the Entity whose descendants should be iterated over.
* \param maxLevel the maximum grid level for which to return descendants. Elements with
* `level > maxLevel` will be omitted from the range.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename Entity>
inline IteratorRange<...> descendantElements(const Entity& e, int maxLevel);
// Entity<int dim, class GridImp, template<int,int,class> class EntityImp>
//! \}
//! \name Entity ranges with (co)dimension template argument
//! \brief Entity ranges which allow specifying the codimension / dimension as a numeric template parameter.
//! \{
//! Iterates over all entities of a GridView with the given codimension.
/**
* This functions returns an object representing the range of entities of codimension
* cd contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop:
*
* \code
* // iterate over all cells in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : entities(gv,Dune::Codim<0>()))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This function allows you to write loops that are parameterized on the codimension of
* the entities. While this allows for extra flexibility (for e.g. some codimension-agnostic
* algorithms), it reduces the code readability. If you don't need this flexibility, consider
* using elements(), facets(), edges() or vertices() instead.
*
* \remark This is the default version of the entities() function. It will always iterate over all
* entities in the GridView, regardless of their Dune::PartitionType. If you are interested
* in entities with specific PartitionType(s), use
* entities(const GV&,Codim<codim>,PartitionSet<partitions>) instead.
*
* \remark If you have to iterate over entities with a specific *dimension*, consider using
* entities(const GV&,Dim<dim>) instead to improve the readability of your code.
*
* \sa entities(const GV&,Codim<codim>,PartitionSet<partitions>)
* \sa entities(const GV&,Dim<dim>)
*
* \relates GridView
* \param gv a GridView object that contains the entities.
* \param cd a Codim object that is used to specify the codimension of the entities by means
* of its template parameter.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, int codim>
inline IteratorRange<...> entities(const GV& gv, Codim<codim> cd);
//! Iterates over all entities of a GridView with the given dimension.
/**
* This functions returns an object representing the range of entities of dimension
* d contained in the GridView gv. The main purpose of this function is to enable iteration
* over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all edges in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : entities(gv,Dune::Dim<1>()))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
* \remark This function allows you to write loops that are parameterized on the codimension of
* the entities. While this allows for extra flexibility (for e.g. some codimension-agnostic
* algorithms), it reduces the code readability. If you don't need this flexibility, consider
* using elements(), facets(), edges() or vertices() instead.
*
* \remark This is the default version of the entities() function. It will always iterate over all
* entities in the GridView, regardless of their Dune::PartitionType. If you are interested
* in entities with specific PartitionType(s), use
* entities(const GV&,Dim<dim>,PartitionSet<partitions>) instead.
*
* \remark If you have to iterate over entities with a specific *codimension*, consider using
* entities(const GV&,Codim<codim>) instead to improve the readability of your code.
*
* \sa entities(const GV&,Dim<dim>,PartitionSet<partitions>)
* \sa entities(const GV&,Codim<codim>)
*
* \relates GridView
* \param gv a GridView object that contains the entities.
* \param d a Dim object that is used to specify the dimension of the entities by means
* of its template parameter.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, int dim>
inline IteratorRange<...> entities(const GV& gv, Dim<dim> d);
//! \}
//! \name Common entity ranges for non-standard parallel partitions
//! \brief The following Entity ranges make it possible to specify a PartitionSet which is sometimes needed in parallel code.
//! \{
//! Iterates over all elements / cells (entities with codimension 0) of a GridView that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of *elements* or *cells* contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function
* is to enable iteration over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all ghost cells in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : elements(gv,Dune::Partitions::ghost))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \sa elements(const GV&)
*
* \relates GridView
* \param gv a GridView object that contains the elements.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the elements must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, unsigned int partitions>
inline IteratorRange<...> elements(const GV& gv, PartitionSet<partitions> ps);
//! Iterates over all facets (entities with codimension 1) of a GridView that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of *facets* contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function
* is to enable iteration over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all interior and border facets in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : facets(gv,Dune::Partitions::interiorBorder))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \sa facets(const GV&)
*
* \relates GridView
* \param gv a GridView object that contains the facets.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the facets must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
/**
* \relates GridView
*/
template<typename GV, unsigned int partitions>
inline IteratorRange<...> facets(const GV& gv, PartitionSet<partitions> ps);
//! Iterates over all edges (entities with dimension 1) of a GridView that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of *edges* contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function
* is to enable iteration over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all interior edges in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : edges(gv,Dune::Partitions::interior))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \sa edges(const GV&)
*
* \relates GridView
* \param gv a GridView object that contains the edges.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the edges must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, unsigned int partitions>
inline IteratorRange<...> edges(const GV& gv, PartitionSet<partitions> ps);
//! Iterates over all vertices (entities with dimension 0) of a GridView that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of *vertices* contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function
* is to enable iteration over those entities by means of a range-based for loop.
*
* Example:
*
* \code
* // iterate over all interior vertices in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : vertices(gv,Dune::Partitions::interior))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \sa vertices(const GV&)
*
* \relates GridView
* \param gv a GridView object that contains the vertices.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the vertices must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, unsigned int partitions>
inline IteratorRange<...> vertices(const GV& gv, PartitionSet<partitions> ps);
//! \}
//! \name Generic entity ranges for non-standard parallel partitions
//! \brief These Entity ranges allow for the maximum flexibility; they are parameterized on both the co(cimension) and the parallel PartitionSet.
//! \{
//! Iterates over all entities of a GridView with the given codimension that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of entities of codimension cd contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function is to
* enable iteration over those entities by means of a range-based for loop:
*
* \code
* // iterate over all interior and border cells in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : entities(gv,Dune::Codim<0>(),Dune::Partitions::interiorBorder))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This function allows you to write loops that are parameterized on the codimension of
* the entities. While this allows for extra flexibility (for e.g. some codimension-agnostic
* algorithms), it reduces the code readability. If you don't need this flexibility, consider
* using elements(), facets(), edges() or vertices() instead.
*
* \remark If you have to iterate over entities with a specific *dimension*, consider using
* entities(const GV&,Dim<dim>,PartitionSet<partitions>) instead to improve the readability
* of your code.
*
* \sa entities(const GV&,Codim<codim>)
* \sa entities(const GV&,Dim<dim>,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the entities.
* \param cd a Codim object that is used to specify the codimension of the entities by means
* of its template parameter.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the entities must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, int codim, unsigned int partitions>
inline IteratorRange<...> entities(const GV& gv gv, Codim<codim> cd, PartitionSet<partitions> ps);
//! Iterates over all entities of a GridView with the given dimension that belong to the given PartitionSet.
/**
* This functions returns an object representing the range of entities of dimension d contained
* in the GridView gv which belong to the PartitionSet ps. The main purpose of this function is to
* enable iteration over those entities by means of a range-based for loop:
*
* \code
* // iterate over all interior and border edges in the LeafGridView
* auto gv = grid.leafGridView();
* for (const auto& e : entities(gv,Dune::Dim<1>(),Dune::Partitions::interiorBorder))
* {
* std::cout << e.geometry().center() << std::endl;
* }
* \endcode
*
* \remark This function allows you to write loops that are parameterized on the dimension of
* the entities. While this allows for extra flexibility (for e.g. some codimension-agnostic
* algorithms), it reduces the code readability. If you don't need this flexibility, consider
* using elements(), facets(), edges() or vertices() instead.
*
* \remark If you have to iterate over entities with a specific *codimension*, consider using
* entities(const GV&,Codim<codim>,PartitionSet<partitions>) instead to improve the readability
* of your code.
*
* \sa entities(const GV&,Dim<dim>)
* \sa entities(const GV&,Codim<codim>,PartitionSet<partitions>)
*
* \relates GridView
* \param gv a GridView object that contains the entities.
* \param d a Dim object that is used to specify the dimension of the entities by means
* of its template parameter.
* \param ps a PartitionSet object that is used to specify the set of Dune::PartitionType to which
* the entities must belong.
* \returns an unspecified object that is guaranteed to fulfil the interface
* of IteratorRange and that can be iterated over using a range-based
* for loop.
*/
template<typename GV, int dim, unsigned int partitions>
inline IteratorRange<...> entities(const GV& gv, Dim<dim> d, PartitionSet<partitions> ps);
//! \}
#else // DOXYGEN
// ******************************************************************************************
// Implementations
// ******************************************************************************************
/**
* Master entity range implementation - all other functions that return an entity range eventually
* end up calling this function. The return type of this function is forwarded by those other functions
* with the help of decltype.
*
* It is thus possible for a grid to use a different type of iterator range object by overloading
* or partially specializing this single function. The specialization has to be placed either in the
* Dune namespace or in the namespace of the GridView object.
*/
template<typename GV, int codim, unsigned int partitions>
inline auto entities(const GV& gv, Codim<codim>, PartitionSet<partitions>)
-> IteratorRange<decltype(gv.template begin<codim,derive_partition_iterator_type<partitions>::value>())>
{
static_assert(0 <= codim && codim <= GV::dimension, "invalid codimension for given GridView");
const PartitionIteratorType pit = derive_partition_iterator_type<partitions>::value;
typedef IteratorRange<decltype(gv.template begin<codim,pit>())> return_type;
return return_type(gv.template begin<codim,pit>(),gv.template end<codim,pit>());
}
/**
* Entity range implementation without PartitionSet parameter. The default implementation obtains the
* standard iterators by calling begin() and end() without specifying a partition type. This makes it
* possible to have user-defined GridView-like objects with a different default partition.
*
* All other functions without PartitionSet parameter forward to this function.
*/
template<typename GV, int codim>
inline auto entities(const GV& gv, Codim<codim>)
-> IteratorRange<decltype(gv.template begin<codim>())>
{
static_assert(0 <= codim && codim <= GV::dimension, "invalid codimension for given GridView");
typedef IteratorRange<decltype(gv.template begin<codim>())> return_type;
return return_type(gv.template begin<codim>(),gv.template end<codim>());
}
/**
* Hierarchic entity range implementation.
*/
template<typename Entity>
inline IteratorRange<typename Entity::HierarchicIterator> descendantElements(const Entity& e, int maxLevel)
{
typedef IteratorRange<typename Entity::HierarchicIterator> return_type;
return return_type(e.hbegin(maxLevel),e.hend(maxLevel));
}
/**
* Intersection range implementation.
*/
template<typename GV, typename Entity>
inline auto intersections(const GV& gv, const Entity& e)
-> IteratorRange<decltype(gv.ibegin(e))>
{
return IteratorRange<decltype(gv.ibegin(e))>(gv.ibegin(e),gv.iend(e));
}
/**
* Remaining implementations - these are mostly copy and paste and making sure to forward to the
* correct function.
*/
template<typename GV, int dim, unsigned int partitions>
inline auto entities(const GV& gv, Dim<dim>, PartitionSet<partitions>)
-> decltype(entities(gv,Codim<GV::dimension - dim>(),PartitionSet<partitions>()))
{
static_assert(0 <= dim && dim <= GV::dimension, "invalid dimension for given GridView");
return entities(gv,Codim<GV::dimension - dim>(),PartitionSet<partitions>());
}
template<typename GV, int dim>
inline auto entities(const GV& gv, Dim<dim>)
-> decltype(entities(gv,Codim<GV::dimension - dim>()))
{
static_assert(0 <= dim && dim <= GV::dimension, "invalid dimension for given GridView");
return entities(gv,Codim<GV::dimension - dim>());
}
template<typename GV, unsigned int partitions>
inline auto elements(const GV& gv, PartitionSet<partitions>)
-> decltype(entities(gv,Codim<0>(),PartitionSet<partitions>()))
{
return entities(gv,Codim<0>(),PartitionSet<partitions>());
}
template<typename GV>
inline auto elements(const GV& gv)
-> decltype(entities(gv,Codim<0>()))
{
return entities(gv,Codim<0>());
}
template<typename GV, unsigned int partitions>
inline auto facets(const GV& gv, PartitionSet<partitions>)
-> decltype(entities(gv,Codim<1>(),PartitionSet<partitions>()))
{
return entities(gv,Codim<1>(),PartitionSet<partitions>());
}
template<typename GV>
inline auto facets(const GV& gv)
-> decltype(entities(gv,Codim<1>()))
{
return entities(gv,Codim<1>());
}
template<typename GV, unsigned int partitions>
inline auto edges(const GV& gv, PartitionSet<partitions>)
-> decltype(entities(gv,Dim<1>(),PartitionSet<partitions>()))
{
return entities(gv,Dim<1>(),PartitionSet<partitions>());
}
template<typename GV>
inline auto edges(const GV& gv)
-> decltype(entities(gv,Dim<1>()))
{
return entities(gv,Dim<1>());
}
template<typename GV, unsigned int partitions>
inline auto vertices(const GV& gv, PartitionSet<partitions>)
-> decltype(entities(gv,Dim<0>(),PartitionSet<partitions>()))
{
return entities(gv,Dim<0>(),PartitionSet<partitions>());
}
template<typename GV>
inline auto vertices(const GV& gv)
-> decltype(entities(gv,Dim<0>()))
{
return entities(gv,Dim<0>());
}
#endif // DOXYGEN
/**
* \} // GIIteration
*/
} // namespace Dune
#endif // DUNE_GRID_COMMON_RANGEGENERATORS_HH
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