Documentation of the Grid Category Components -- Grid-With-Boundary Concept

Vertex (Edge, Cell, ...) Grid Range Concept

Grid-With-Boundary Concept

Grid-With-Boundary Concept

Description

A Grid-With-Boundary allows to query whether a facet is a boundary facet. Moreover, it defines a special cell handle for an `outside cell', and allows to query whether a cell is inside the grid.

Refinement of

Grid
Cell Grid Range
Facet Grid Range
The cell type of a Grid-With-Boundary is a model of Grid Cell and of Facet Grid Range.

G is a type which is a model of Grid-With-Boundary
g is an object of type G
c is an object of type G::Cell
h is an object of type G::cell_handle
f is an object of type G::Facet
fc is an object of type G::FacetOnCellIterator

Definitions

Associated types

No new ones, but the requirements on G::Cell are strengthened.

Name

Expression

Description

cell type

G::Cell

the cell element type of G

model of Grid Cell and of Facet Grid Range

Valid Expressions

Name	Expression	Type requirements	return type
inside test	`g.IsInside(c)`		`bool`
inside test	`g.IsInside(h)`		`bool`
boundary test	`g.IsOnBoundary(fc)`		`bool`
boundary test	`g.IsOnBoundary(f)`		`bool`
outer cell handle	`g.outer_cell_handle()`		`G::cell_handle`

Expression semantics

Name	Expression	Precondition	Semantics	Postcondition
inside test	`g.IsInside(c);`	`c` is bound to `g` `c` is valid or `c.handle() == g.outer_cell_handle()`	Test if `c` is inside the grid	true if `c` is valid for `g`. false if `c.handle() == g.outer_cell_handle()`
inside test	`g.IsInside(h);`	`h` is valid or `h == g.outer_cell_handle()`	Test if `h` is handle of a cell inside the grid	true if `h` is valid for `g`. false if `h == g.outer_cell_handle()`
boundary test	`g.IsOnBoundary(f)`	`f` is valid	Returns `true` if `f` is a boundary facet of `g`
boundary test	`g.IsOnBoundary(fc)`	`fc` is valid	equivalent to `g.IsOnBoundary(*fc)`.
outer cell handle	`h = g.outer_cell_handle();`		return a handle denoting an `outside' cell	`g.IsInside(h)` is false

Invariants

	`g.IsInside(g.outer_cell_handle()) == false`
	`g.IsInside(c) == g.IsInside(c.handle())`
	`g.IsOnBoundary(fc) == ! g.IsInside(fc.OtherCell())`X
	`g.IsOnBoundary(f) == (!g.IsInside(f.TheCell()) \|\| !g.IsInside(f.OtherCell()))`
	`g.IsInside()` evaluates to `true` for all cells in the range [`g.FirstCell()`,`g.EndCell()`).

Refinements

Models

Complex2D

Notes

It does however not follow that if ! g.IsInside(h), then h == g.outer_cell_handle(), because it is possible that there are many different handles denoting an outer cell. For example, when we consider Cartesian grids, cells with an logical index (i,j) outside the grid range would satisfy ! g.IsInside(c) but do not necessarily possess a handle equal to g.outer_cell_handle().
It is possible to create a cell with the `outer' cell handle:
```
 Cell c = g.cell(g.outer_cell_handle())
```
is possible, as is
```
Cell c = fc.OtherCell()
```
when g.IsOnBoundary(fc) is true. However, the only operation guaranteed to work with c is the query g.IsInside(c) which evaluates to false.