mixed_grid/
mixed_grid.rs

1use ndelement::types::ReferenceCellType;
2use ndgrid::grid::local_grid::MixedGridBuilder;
3use ndgrid::traits::{Builder, Entity, Geometry, GmshExport, Grid, Point, Topology};
4
5/// Creating a (serial) mixed grid
6///
7/// In a mixed grid, multiple cell types can be present and mutiple finite elements can be used to
8/// represent the geometry of cells.
9fn main() {
10    // When creating the grid builder, we give the physical/geometric dimension (3)
11    let mut b = MixedGridBuilder::<f64>::new(2);
12    // Add nine points with ids 0 to 8
13    b.add_point(0, &[0.0, 0.0]);
14    b.add_point(1, &[0.5, -0.3]);
15    b.add_point(2, &[1.0, 0.0]);
16    b.add_point(3, &[2.0, 0.0]);
17    b.add_point(4, &[-0.3, 0.5]);
18    b.add_point(5, &[0.5, 0.5]);
19    b.add_point(6, &[0.0, 1.0]);
20    b.add_point(7, &[1.0, 1.0]);
21    b.add_point(8, &[2.0, 1.0]);
22    // Add a linear triangle cell. The inputs to add_cell are
23    // (id, (cell type, cell degree, vertices))
24    b.add_cell(0, (ReferenceCellType::Triangle, 1, &[2, 7, 6]));
25    // Add a quadratic triangle cell. The edge that is shared with cell 0 is straight to ensure
26    // that there are no discontinuities in the grid.
27    b.add_cell(1, (ReferenceCellType::Triangle, 2, &[0, 2, 6, 5, 4, 1]));
28    // Add a quadrilateral cell
29    b.add_cell(2, (ReferenceCellType::Quadrilateral, 1, &[2, 3, 7, 8]));
30    // Create the grid
31    let grid = b.create_grid();
32
33    // Print the vertices of each triangle cell: this will only include the three points
34    // for each cell as these are the topological vertices (ie the 0-dimensional entities at
35    // each corner of the cell), not the geometric points
36    for cell in grid.entity_iter(ReferenceCellType::Triangle) {
37        println!(
38            "triangle cell {}: {:?}",
39            cell.local_index(),
40            cell.topology()
41                .sub_entity_iter(ReferenceCellType::Point)
42                .collect::<Vec<_>>(),
43        );
44    }
45    // Print the geometric points that definie each cells position in space. Note that
46    // The indexing of these points may differ from the indexing used for the topological vertices.
47    let mut coords = vec![0.0; 2];
48    for cell in grid.entity_iter(ReferenceCellType::Triangle) {
49        println!("triangle cell {}:", cell.local_index());
50        for p in cell.geometry().points() {
51            p.coords(&mut coords);
52            println!("  point {}: {:?}", p.index(), coords);
53        }
54    }
55    // Print the vertices of each quadrilateral cell
56    for cell in grid.entity_iter(ReferenceCellType::Quadrilateral) {
57        println!(
58            "quadrilateral cell {}: {:?} ",
59            cell.local_index(),
60            cell.topology()
61                .sub_entity_iter(ReferenceCellType::Point)
62                .collect::<Vec<_>>()
63        );
64    }
65
66    // Export the mesh in Gmsh format
67    grid.export_as_gmsh("_mixed.msh");
68}
mixed_grid/mixed_grid.rs

mixed_grid/
mixed_grid.rs
