Documentation of the Grid Category Components -- enumerated subrange Type

enumerated_subrange Type

`enumerated_subrange` Type

Declaration

template<class G>
class enumerated_subrange;

Description

The class template enumerated_subrange implements a sub-range of a grid. Cells and vertices must be explicitly joined to the rangeX. Iteration over facets is provided.

Model of

Vertex Grid Range
Edge Grid RangeX
Facet Grid Range
Cell Grid Range

Definition

Defined in enumerated-subrange.h

Template parameters

Parameter	Description	Default
`G`	the base grid

Type requirements

G must be a model of Grid.

Public base classes

None.

Members

New members

Member	Description
*Types*
`vertex_range_ref`	reference to vertex range, defined as `vertex_range_ref`<G,R>
`cell_range_ref`	reference to cell range, defined as `cell_range_ref<G,R>`
*Functions*
`append_vertex(vertex_handle v)`	add a new vertex to `r`
`append_cell(cell_handle c)`	add a new cell to `r`
`vertex_range_ref vertices()`	reference to vertex range
`cell_range_ref cells()`	reference to cell range

Example

  a_grid_type g;
  ...
  enumerated_subrange<a_grid_type>  r(g); // empty range
  // fill with cells
  for(gt::CellIterator c(g); ! c.IsDone(); ++c)
    if(predicate(*c)) // some predicate on cells
      r.append_cell(c.handle());
  // determine vertex set of r.cells()
  ConstructSubrangeFromCells(r,r.cells());

Notes

The availability of these operations means that instances of enumerated_subrange do not ensure that their vertex range is the vertex set of the their cell range. It is the responsibility of the client to ensure this if it is needed. If this equality is not satisfied, it simply means that the range does not represent a dimension-homogeneous grid.
Note, however, that there are components that can help in ensuring this property in a subrange, for example the ConstructSubrangeFromCells algorithm.
The Edge Grid Range concept is supported in 2D only (when edges and facets coincide). The current implementation simply assumes that the template parameter G is two-dimensional; for future extension, a compile-time switch on the dimension should be performed here.
The element types and incidence iterator types of enumerated_subrange are forwarded from the template parameter G. There is currently no mechanism implemented to determine at compile time which types are provided by G, therefore, some default assumption has to be made, excluding some simpler grid types from the set of possible parameters. This restriction is artificial and should be removed.

enumerated_subrange Type

`enumerated_subrange` Type