Dune Core Modules (unstable)
Mesh entities of codimension 0 ("elements") allow to visit all intersections with "neighboring" elements and with the domain boundary. More...
#include <dune/grid/common/intersectioniterator.hh>
Public Types  
typedef IntersectionIteratorImp  Implementation 
type of underlying implementation More...  
typedef Dune::Intersection< GridImp, IntersectionImp >  Intersection 
Type of Intersection this IntersectionIterator points to.  
Public Member Functions  
Implementation &  impl () 
access to the underlying implementation More...  
const Implementation &  impl () const 
access to the underlying implementation More...  
Dereferencing  
Intersection  operator* () const 
Dereferencing operator.  
const Intersection *  operator> () const 
Pointer operator.  
Compare methods  
bool  operator== (const IntersectionIterator &rhs) const 
Checks for equality. Only Iterators pointing to the same intersection from the same Entity are equal. Pointing to the same intersection from neighbor is unequal as inside and outside are permuted.  
bool  operator!= (const IntersectionIterator &rhs) const 
Checks for inequality. Only Iterators pointing to the same intersection from the same Entity are equal. Pointing to the same intersection from neighbor is unequal as inside and outside are permuted.  
IntersectionIterator &  operator++ () 
Preincrement operator. Proceed to next intersection.  
IntersectionIterator  operator++ (int) 
Postincrement operator. Proceed to next intersection.  
IntersectionIterator ()  
Default constructor.  
Implementor interface  
bool  equals (const IntersectionIterator &rhs) const 
forward equality check to realIterator  
IntersectionIterator (const Implementation &impl)  
Detailed Description
template<class GridImp, class IntersectionIteratorImp, class IntersectionImp>
class Dune::IntersectionIterator< GridImp, IntersectionIteratorImp, IntersectionImp >
Mesh entities of codimension 0 ("elements") allow to visit all intersections with "neighboring" elements and with the domain boundary.
 Template Parameters

GridImp Type that is a model of Dune::Grid IntersectionIteratorImp Class template that is a model of Dune::IntersectionIterator
 Warning
 The number of neigbors may be different from the number of faces/edges of an element!
Overview
Intersections are codimension 1 objects. These intersections are accessed via an IntersectionIterator. This allows the implementation of nonmatching grids, as one face can now consist of several intersections. In a conforming mesh such an intersection corresponds to an entity of codimension 1 but in the general nonconforming case there will be no entity in the mesh that directly corresponds to the intersection. Thus, the IntersectionIterator describes these intersections implicitly.
Engine Concept
The IntersectionIterator class template wraps an object of type IntersectionIteratorImp and forwards all member function calls to corresponding members of this class. In that sense IntersectionIterator defines the interface and IntersectionIteratorImp supplies the implementation.
Intersections, leaf grid and level grid
On an entity e of codimension zero there are two ways to create IntersectionIterators by either using ilevelbegin() / ilevelend() or ileafbegin()/ileafend(). In the first case intersections with neighboring entities having the same level as e are traversed; in the second case ileafbegin()==ileafend() if e is not a leaf otherwise all intersections with neighboring leaf entities are traversed.
Consider a situation where two elements a and b have a common intersection. Element b has been refined into an element c and d, while a has not been refined. In one space dimension this situation is depicted in the figure below.
Here the rule is the following: The LevelIntersectionIterator delivers all intersections with elements on the same level, the LeafIntersectionIterator delivers the intersections with all leaf elements if it has been started on a leaf element. Both iterators also stop at intersections with the grid boundary. According to this rule the level intersection iterator started at element a in the example above delivers an intersection with b and the left grid boundary, whereas the leaf intersection iterator returns c instead of b. Starting on entity c the level intersection iterator returns d and the intersection with the left boundary of the level 1 grid, but the leaf intersection iterator returns both d and a. Finally, starting on b the level intersection iterator returns a and the right boundary, but the leaf intersection iterator is empty since b is not a leaf entity of the grid. Starting on d both the level and the leaf intersection iterators will return the element c together with the right grid boundary.
Member Typedef Documentation
◆ Implementation
typedef IntersectionIteratorImp Dune::IntersectionIterator< GridImp, IntersectionIteratorImp, IntersectionImp >::Implementation 
type of underlying implementation
 Warning
 Implementation details may change without prior notification.
Constructor & Destructor Documentation
◆ IntersectionIterator()

inline 
Copy Constructor from IntersectionIteratorImp
Member Function Documentation
◆ impl() [1/2]

inline 
access to the underlying implementation
 Warning
 Implementation details may change without prior notification.
◆ impl() [2/2]

inline 
access to the underlying implementation
 Warning
 Implementation details may change without prior notification.
The documentation for this class was generated from the following files:
 dune/grid/common/grid.hh
 dune/grid/common/intersectioniterator.hh