Dune Core Modules (2.8.0)
Classes | |
class | Dune::Mapper< G, MapperImp, IndexType > |
Mapper interface. More... | |
class | Dune::MultipleCodimMultipleGeomTypeMapper< GV > |
Implementation class for a multiple codim and multiple geometry type mapper. More... | |
class | Dune::LeafMultipleCodimMultipleGeomTypeMapper< G > |
Multiple codim and multiple geometry type mapper for leaf entities. More... | |
class | Dune::LevelMultipleCodimMultipleGeomTypeMapper< G > |
Multiple codim and multiple geometry type mapper for entities of one level. More... | |
class | Dune::SingleCodimSingleGeomTypeMapper< GV, c > |
Implementation class for a single codim and single geometry type mapper. More... | |
class | Dune::LeafSingleCodimSingleGeomTypeMapper< G, c > |
Single codim and single geometry type mapper for leaf entities. More... | |
class | Dune::LevelSingleCodimSingleGeomTypeMapper< G, c > |
Single codim and single geometry type mapper for entities of one level. More... | |
Typedefs | |
using | Dune::MCMGLayout = std::function< size_t(GeometryType, int)> |
layout function for MultipleCodimMultipleGeomTypeMapper More... | |
Functions | |
template<int codim> | |
MCMGLayout | Dune::mcmgLayout (Codim< codim >) |
layout for entities of codimension codim More... | |
template<int dim> | |
MCMGLayout | Dune::mcmgLayout (Dim< dim >) |
layout for entities of dimension dim More... | |
MCMGLayout | Dune::mcmgElementLayout () |
layout for elements (codim-0 entities) More... | |
MCMGLayout | Dune::mcmgVertexLayout () |
layout for vertices (dim-0 entities) More... | |
Detailed Description
What is a Mapper ?
A mapper class is used to attach user-defined data to a subset of the grid entities \(E^\prime\subseteq E\).
It is assumed that the data \(D(E^\prime)\) associated with \(E^\prime\) is stored in an array. The array can be viewed as a map
\[ a : I_{E^\prime} \to D(E^\prime) \]
from the consecutive, zero-starting index set \( I_{E^\prime} = \{0, \ldots, |E^\prime|-1\}\) of \(E^\prime\) to the data set.
The mapper class provides a mapping
\[ m : E^\prime \to I_{E^\prime} \]
from the entity set to the index set.
Access from a grid entity \(e\in E^\prime\) to its associated data element \(d_e\) then is a two step process:
\[ a(m(e)) = d_e. \]
Different Kinds of Mappers
There are different kinds of mappers depending on functionality and efficiency of their implementation. The user selects an appropriate mapper depending on her/his needs. All mappers conform to the same interface.
Index based Mappers
An index-based mapper is allocated for a grid and can be used as long as the grid is not changed (i.e. refined, coarsened or load balanced). The implementation of static mappers is based on a Dune::IndexSet and is typically of \(O(1)\) complexity with a very small constant. Index-based mappers are only available for restricted (but usually sufficient) entity sets.
Id based Mappers
An id-based mapper can also be used while a grid changes. For that it has to be implemented on the basis of a Dune::IdSet. This may be relatively slow because the data type used for ids is usually not an int and the non-consecutive ids require more complicated search data structures (typically a map). Access is therefore at least \(O(\log |E^\prime|)\). On the other hand, id-based mappers can treat arbitrary entity sets \(E^\prime\).
Mapper Interface
This interface is implemented by the class template Dune::Mapper. For a full documentation see the description of this class.
The function Dune::Mapper::index delivers the index for an entity. Note that that for performance reasons it is usually not checked whether the entity is really in the entity set.
The functions Dune::Mapper::index delivers the index for a (sub-)entity
The function Dune::Mapper::size returns the size of the entity set, i.e. \(|E^\prime|\)
The different implementations of the mapper interface are listed below.
Overview of Different Mapper Implementations
Mappers and Mesh Changes
Typedef Documentation
◆ MCMGLayout
using Dune::MCMGLayout = typedef std::function<size_t(GeometryType, int)> |
layout function for MultipleCodimMultipleGeomTypeMapper
The layout function indicates which entity types are contained in the mapper. It is called for each GeometryType
and the grid dimension. A true
value indicates the geometry type is part of the map; false
that it is not.
For commonly used layouts containing only entities of a fixed dimension or codimension, convenience functions returning a MCMGLayout
are provided.
The following example is equivalent to mcmgElementLayout():
Function Documentation
◆ mcmgElementLayout()
|
inline |
◆ mcmgLayout() [1/2]
MCMGLayout Dune::mcmgLayout | ( | Codim< codim > | ) |
layout for entities of codimension codim
References Dune::FloatCmp::gt().
Referenced by Dune::mcmgElementLayout(), and Dune::mcmgVertexLayout().
◆ mcmgLayout() [2/2]
MCMGLayout Dune::mcmgLayout | ( | Dim< dim > | ) |
layout for entities of dimension dim
References Dune::FloatCmp::gt().
◆ mcmgVertexLayout()
|
inline |