Add builder for mixed grid

src/grid/mixed_grid/builder.rs

@@ -0,0 +1,105 @@
+//! Grid builder
+
+use crate::grid::mixed_grid::grid::SerialMixedGrid;
+use crate::traits::builder::Builder;
+use crate::types::ReferenceCellType;
+use bempp_element::element::{create_element, ElementFamily, Inverse};
+use bempp_traits::element::{Continuity, FiniteElement};
+use num::Float;
+use rlst_common::types::Scalar;
+use rlst_dense::{rlst_array_from_slice2, rlst_dynamic_array2};
+use std::collections::HashMap;
+
+pub struct SerialMixedGridBuilder<const GDIM: usize, T: Float + Scalar<Real = T> + Inverse> {
+    elements_to_npoints: HashMap<(ReferenceCellType, usize), usize>,
+    points: Vec<T>,
+    cells: Vec<usize>,
+    cell_types: Vec<ReferenceCellType>,
+    cell_degrees: Vec<usize>,
+    point_indices_to_ids: Vec<usize>,
+    cell_indices_to_ids: Vec<usize>,
+    point_ids_to_indices: HashMap<usize, usize>,
+    cell_ids_to_indices: HashMap<usize, usize>,
+}
+
+impl<const GDIM: usize, T: Float + Scalar<Real = T> + Inverse> Builder<GDIM>
+    for SerialMixedGridBuilder<GDIM, T>
+{
+    type GridType = SerialMixedGrid<T>;
+    type T = T;
+    type CellData = (Vec<usize>, ReferenceCellType, usize);
+    type GridMetadata = ();
+
+    fn new(_data: ()) -> Self {
+        Self {
+            elements_to_npoints: HashMap::new(),
+            points: vec![],
+            cells: vec![],
+            cell_types: vec![],
+            cell_degrees: vec![],
+            point_indices_to_ids: vec![],
+            cell_indices_to_ids: vec![],
+            point_ids_to_indices: HashMap::new(),
+            cell_ids_to_indices: HashMap::new(),
+        }
+    }
+
+    fn new_with_capacity(npoints: usize, ncells: usize, _data: ()) -> Self {
+        Self {
+            elements_to_npoints: HashMap::new(),
+            points: Vec::with_capacity(npoints * Self::GDIM),
+            cells: vec![],
+            cell_types: vec![],
+            cell_degrees: vec![],
+            point_indices_to_ids: Vec::with_capacity(npoints),
+            cell_indices_to_ids: Vec::with_capacity(ncells),
+            point_ids_to_indices: HashMap::new(),
+            cell_ids_to_indices: HashMap::new(),
+        }
+    }
+
+    fn add_point(&mut self, id: usize, data: [T; GDIM]) {
+        self.point_ids_to_indices
+            .insert(id, self.point_indices_to_ids.len());
+        self.point_indices_to_ids.push(id);
+        self.points.extend_from_slice(&data);
+    }
+
+    fn add_cell(&mut self, id: usize, cell_data: (Vec<usize>, ReferenceCellType, usize)) {
+        let points_per_cell =
+            if let Some(npts) = self.elements_to_npoints.get(&(cell_data.1, cell_data.2)) {
+                *npts
+            } else {
+                let npts = create_element::<T>(
+                    ElementFamily::Lagrange,
+                    cell_data.1,
+                    cell_data.2,
+                    Continuity::Continuous,
+                )
+                .dim();
+                self.elements_to_npoints
+                    .insert((cell_data.1, cell_data.2), npts);
+                npts
+            };
+        assert_eq!(cell_data.0.len(), points_per_cell);
+        self.cell_ids_to_indices
+            .insert(id, self.cell_indices_to_ids.len());
+        self.cell_indices_to_ids.push(id);
+        self.cells.extend_from_slice(&cell_data.0);
+        self.cell_types.push(cell_data.1);
+        self.cell_degrees.push(cell_data.2);
+    }
+
+    fn create_grid(&self) -> Self::GridType {
+        // TODO: remove this transposing
+        let npts = self.point_indices_to_ids.len();
+        let mut points = rlst_dynamic_array2!(T, [npts, 3]);
+        points.fill_from(rlst_array_from_slice2!(
+            T,
+            &self.points,
+            [npts, 3],
+            [1, npts]
+        ));
+        SerialMixedGrid::new(points, &self.cells, &self.cell_types, &self.cell_degrees)
+    }
+}