dolfinx::io::cells Namespace Reference
Functions for the re-ordering of input mesh topology to the DOLFINx ordering, and transpose orderings for file output. More...
Functions | |
| int | cell_degree (mesh::CellType type, int num_nodes) |
| Get the Lagrange order of a given cell with a given number of nodes. | |
| std::vector< std::uint16_t > | perm_vtk (mesh::CellType type, int num_nodes) |
| Permutation array to map from VTK to DOLFINx node ordering. | |
| std::vector< std::uint16_t > | perm_gmsh (mesh::CellType type, int num_nodes) |
| Permutation array to map from Gmsh to DOLFINx node ordering. | |
| std::vector< std::uint16_t > | transpose (std::span< const std::uint16_t > map) |
| Compute the transpose of a re-ordering map. | |
| std::vector< std::int64_t > | apply_permutation (std::span< const std::int64_t > cells, std::array< std::size_t, 2 > shape, std::span< const std::uint16_t > p) |
| Permute cell topology by applying a permutation array for each cell. | |
| std::int8_t | get_vtk_cell_type (mesh::CellType cell, int dim) |
| Get VTK cell identifier. | |
Detailed Description
Functions for the re-ordering of input mesh topology to the DOLFINx ordering, and transpose orderings for file output.
Basix ordering is used for the geometry nodes, and is shown below for a range of cell types.
Triangle: Triangle6: Triangle10:
v
^
|
2 2 2
|`\ |`\ | \
| `\ | `\ 6 4
| `\ 4 `3 | \
| `\ | `\ 5 9 3
| `\ | `\ | \
0----------1 --> u 0-----5----1 0---7---8---1
Quadrilateral: Quadrilateral9: Quadrilateral16:
v
^
|
2-----------3 2-----7-----3 2--10--11---3
| | | | | |
| | | | 7 14 15 9
| | 5 8 6 | |
| | | | 6 12 13 8
| | | | | |
0-----------1 --> u 0-----4-----1 0---4---5---1
Tetrahedron: Tetrahedron10: Tetrahedron20
v
/
2 2 2
,/|`\ ,/\`\ ,/|`\
,/ \ `\ ,/ \ `\. 13 | `9
,/ '. `\ ,8 '. `6 ,/ 4 `\
,/ | `\ ,/ 4 `\ 12 19 | `8
,/ | `\ ,/ | `\ ,/ | `\
0-----------'.--------1 -> u 0--------9--'.--------1 0-----14----'.--15----1
`\. | ,/ `\. | ,/ `\. 17 | 16 ,/
`\. | ,/ `\. | ,5 10. 18 5 ,6
`\. '. ,/ `7. '. ,/ `\. . 7
`\. |/ `\. |/ 11. |/
`3 `3 `3
`\.
w
Hexahedron: Hexahedron27:
w
6----------7 6----19----7
/| ^ v /| /| /|
/ | | / / | 17 | 25 18|
/ | | / / | / 14 24 / 15
4----------5 | 4----16----5 |
| | +--|---|--> u |22 | 26 | 23|
| 2------+---3 | 2----13+---3
| / | / 10 / 21 12 /
| / | / | 9 20 | 11
|/ |/ |/ |/
0----------1 0-----8----1
Prism: Prism15:
w
^
|
3 3
,/|`\ ,/|`\
,/ | `\ 12 | 13
,/ | `\ ,/ | `\
4------+------5 4------14-----5
| | | | 8 |
| ,/|`\ | | | |
| ,/ | `\ | | | |
|,/ 0 `\| 10 0 11
./| ,/ `\ |\ | ,/ `\ |
/ | ,/ `\ | `\ | ,6 `7 |
u |,/ `\| v |,/ `\|
1-------------2 1------9------2
Pyramid: Pyramid13:
4 4
,/|\ ,/|\
,/ .'|\ ,/ .'|\
v ,/ | | \ ,/ | | \
\. ,/ .' | `. ,/ .' | `.
\. | '. \ 11 | 12 \
,/ \. .' w | \ ,/ .' | \
,/ \. | ^ | \ ,/ 7 | 9
2----------\'--|-3 `. 2-------10-.'----3 `.
`\ | \.| `\ \ `\ | `\ \
`\ .' +----`\ - \ -> u `6 .' 8 \
`\ | `\ \ `\ | `\ \
`\.' ` `\ `\.' ` `\
0-----------------1 0--------5--------1
Function Documentation
◆ apply_permutation()
| std::vector< std::int64_t > apply_permutation | ( | std::span< const std::int64_t > | cells, |
| std::array< std::size_t, 2 > | shape, | ||
| std::span< const std::uint16_t > | p ) |
Permute cell topology by applying a permutation array for each cell.
- Parameters
-
[in] cells Array of cell topologies, with each row representing a cell (row-major storage). [in] shape Shape of the cells array. [in] p Permutation array that maps a_p[i] = a[p[i]], where a_p is the permuted array.
- Returns
- Permuted cell topology, where for a cell v_new[i] = / v_old[map[i]]. The storage is row-major and the shape is the same as cells.
◆ cell_degree()
| int cell_degree | ( | mesh::CellType | type, |
| int | num_nodes ) |
Get the Lagrange order of a given cell with a given number of nodes.
- Parameters
-
[in] type Cell shape. [in] num_nodes Number of cell 'nodes'
- Returns
- Lagrange order of the cell type.
◆ get_vtk_cell_type()
| std::int8_t get_vtk_cell_type | ( | mesh::CellType | cell, |
| int | dim ) |
Get VTK cell identifier.
- Parameters
-
[in] cell Cell type. [in] dim Topological dimension of the cell.
- Returns
- VTK cell identifier.
◆ perm_gmsh()
| std::vector< std::uint16_t > perm_gmsh | ( | mesh::CellType | type, |
| int | num_nodes ) |
Permutation array to map from Gmsh to DOLFINx node ordering.
- Parameters
-
[in] type Cell shape. [in] num_nodes Number of cell 'nodes'
- Returns
- Permutation array p for permuting from Gmsh ordering to DOLFINx ordering, i.e. a_dolfin[i] = a_gmsh[p[i]].
If p = [0, 2, 1, 3] and a = [10, 3, 4, 7], then a_p / =[a[p[0]], a[p[1]], a[p[2]], a[p[3]]] = [10, 4, 3, 7].
◆ perm_vtk()
| std::vector< std::uint16_t > perm_vtk | ( | mesh::CellType | type, |
| int | num_nodes ) |
Permutation array to map from VTK to DOLFINx node ordering.
- Parameters
-
[in] type Cell shape. [in] num_nodes Number of cell 'nodes'
- Returns
- Permutation array p for permuting from VTK ordering to DOLFINx ordering, i.e. a_dolfin[i] = a_vtk[p[i]].
If p = [0, 2, 1, 3] and a = [10, 3, 4, 7], then a_p = / [a[p[0]], a[p[1]], a[p[2]], a[p[3]]] = [10, 4, 3, 7].
◆ transpose()
| std::vector< std::uint16_t > transpose | ( | std::span< const std::uint16_t > | map | ) |
Compute the transpose of a re-ordering map.
- Parameters
-
[in] map A re-ordering map.
- Returns
- Transpose of the map. E.g., is map = {1, 2, 3, 0}, the transpose will be {3 , 0, 1, 2 }.
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