Initial commit
This commit is contained in:
redclawsystems
@@ -0,0 +1,613 @@
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// Copyright (c) 2024 RustyTorch++ Team
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// Licensed under the Apache License, Version 2.0
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//! Mesh refinement operations.
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use crate::error::{FeaResult, MeshError};
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use crate::mesh::{Element, ElementType, Node, NodeId};
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use std::collections::HashMap;
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/// Mesh refinement operations.
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pub struct MeshRefinement;
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impl MeshRefinement {
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/// Uniform refinement by subdividing all elements.
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pub fn uniform_refinement(mesh: &crate::mesh::Mesh) -> FeaResult<crate::mesh::Mesh> {
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let mut refined_mesh = crate::mesh::Mesh::new(mesh.spatial_dimension)?;
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// Copy existing nodes first
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let mut node_mapping = HashMap::new();
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for (node_id, node) in &mesh.nodes {
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let new_node = Node {
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coordinates: node.coordinates.clone(),
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dofs: node.dofs.clone(),
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label: node.label.clone(),
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};
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let new_id = refined_mesh.add_node(new_node);
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node_mapping.insert(*node_id, new_id);
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}
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// Track edge midpoints to avoid duplication
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let mut edge_midpoints: HashMap<(NodeId, NodeId), NodeId> = HashMap::new();
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// Helper to get or create edge midpoint
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let get_edge_midpoint = |n1: NodeId,
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n2: NodeId,
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edge_midpoints: &mut HashMap<(NodeId, NodeId), NodeId>,
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refined_mesh: &mut crate::mesh::Mesh,
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mesh: &crate::mesh::Mesh|
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-> NodeId {
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let edge_key = if n1 < n2 { (n1, n2) } else { (n2, n1) };
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if let Some(&mid_id) = edge_midpoints.get(&edge_key) {
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return mid_id;
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}
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// Create midpoint node
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let node1 = &mesh.nodes[&n1];
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let node2 = &mesh.nodes[&n2];
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let midpoint_coords = (&node1.coordinates + &node2.coordinates) * 0.5;
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let mid_node = Node {
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coordinates: midpoint_coords,
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dofs: node1.dofs.clone(), // Use same DOF types as parent nodes
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label: None,
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};
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let mid_id = refined_mesh.add_node(mid_node);
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edge_midpoints.insert(edge_key, mid_id);
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mid_id
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};
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// Process each element
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for element in mesh.elements.values() {
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match element.element_type {
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ElementType::Tri3 => {
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// Triangle subdivision into 4 triangles
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if element.nodes.len() != 3 {
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return Err(MeshError::InvalidElement(format!(
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"Triangle element requires 3 nodes, found {}",
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element.nodes.len()
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))
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.into());
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}
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let n0 = node_mapping[&element.nodes[0]];
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let n1 = node_mapping[&element.nodes[1]];
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let n2 = node_mapping[&element.nodes[2]];
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// Create edge midpoints
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let m01 = get_edge_midpoint(
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element.nodes[0],
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element.nodes[1],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m12 = get_edge_midpoint(
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element.nodes[1],
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element.nodes[2],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m20 = get_edge_midpoint(
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element.nodes[2],
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element.nodes[0],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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// Create 4 new triangles
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refined_mesh.add_element(Element::new(
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ElementType::Tri3,
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vec![n0, m01, m20],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tri3,
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vec![m01, n1, m12],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tri3,
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vec![m20, m12, n2],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tri3,
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vec![m01, m12, m20],
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element.material_id,
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)?);
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}
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ElementType::Quad4 => {
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// Quad subdivision into 4 quads
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if element.nodes.len() != 4 {
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return Err(MeshError::InvalidElement(format!(
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"Quad element requires 4 nodes, found {}",
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element.nodes.len()
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))
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.into());
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}
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let n0 = node_mapping[&element.nodes[0]];
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let n1 = node_mapping[&element.nodes[1]];
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let n2 = node_mapping[&element.nodes[2]];
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let n3 = node_mapping[&element.nodes[3]];
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// Create edge midpoints
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let m01 = get_edge_midpoint(
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element.nodes[0],
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element.nodes[1],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m12 = get_edge_midpoint(
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element.nodes[1],
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element.nodes[2],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m23 = get_edge_midpoint(
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element.nodes[2],
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element.nodes[3],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m30 = get_edge_midpoint(
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element.nodes[3],
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element.nodes[0],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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// Create center point
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let center_coords = (&mesh.nodes[&element.nodes[0]].coordinates
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+ &mesh.nodes[&element.nodes[1]].coordinates
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+ &mesh.nodes[&element.nodes[2]].coordinates
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+ &mesh.nodes[&element.nodes[3]].coordinates)
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* 0.25;
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let center_node = Node {
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coordinates: center_coords,
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dofs: mesh.nodes[&element.nodes[0]].dofs.clone(),
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label: None,
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};
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let center = refined_mesh.add_node(center_node);
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// Create 4 new quads
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refined_mesh.add_element(Element::new(
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ElementType::Quad4,
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vec![n0, m01, center, m30],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Quad4,
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vec![m01, n1, m12, center],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Quad4,
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vec![center, m12, n2, m23],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Quad4,
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vec![m30, center, m23, n3],
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element.material_id,
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)?);
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}
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ElementType::Tet4 => {
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// Tetrahedral subdivision into 8 tets (octahedral subdivision)
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if element.nodes.len() != 4 {
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return Err(MeshError::InvalidElement(format!(
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"Tetrahedral element requires 4 nodes, found {}",
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element.nodes.len()
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))
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.into());
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}
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let n0 = node_mapping[&element.nodes[0]];
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let n1 = node_mapping[&element.nodes[1]];
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let n2 = node_mapping[&element.nodes[2]];
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let n3 = node_mapping[&element.nodes[3]];
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// Create all edge midpoints (6 edges for tet)
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let m01 = get_edge_midpoint(
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element.nodes[0],
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element.nodes[1],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m02 = get_edge_midpoint(
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element.nodes[0],
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element.nodes[2],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m03 = get_edge_midpoint(
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element.nodes[0],
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element.nodes[3],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m12 = get_edge_midpoint(
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element.nodes[1],
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element.nodes[2],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m13 = get_edge_midpoint(
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element.nodes[1],
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element.nodes[3],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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let m23 = get_edge_midpoint(
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element.nodes[2],
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element.nodes[3],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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// Create 8 new tets - 4 corner tets and 4 from octahedron in center
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// Corner tets
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![n0, m01, m02, m03],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m01, n1, m12, m13],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m02, m12, n2, m23],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m03, m13, m23, n3],
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element.material_id,
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)?);
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// Octahedron subdivision into 4 tets
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m01, m02, m03, m13],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m01, m02, m12, m13],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m02, m03, m13, m23],
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element.material_id,
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)?);
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refined_mesh.add_element(Element::new(
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ElementType::Tet4,
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vec![m02, m12, m13, m23],
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element.material_id,
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)?);
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}
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ElementType::Hex8 => {
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// Hexahedral subdivision into 8 hexahedra
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if element.nodes.len() != 8 {
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return Err(MeshError::InvalidElement(format!(
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"Hexahedral element requires 8 nodes, found {}",
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element.nodes.len()
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))
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.into());
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}
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// Map original nodes
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let original_nodes: Vec<_> =
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element.nodes.iter().map(|&n| node_mapping[&n]).collect();
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// Create all edge midpoints (12 edges for hex)
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let mut edge_mids = Vec::new();
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let edge_pairs = [
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(0, 1),
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(1, 2),
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(2, 3),
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(3, 0), // Bottom face
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(4, 5),
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(5, 6),
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(6, 7),
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(7, 4), // Top face
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(0, 4),
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(1, 5),
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(2, 6),
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(3, 7), // Vertical edges
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];
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for &(i, j) in &edge_pairs {
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let mid = get_edge_midpoint(
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element.nodes[i],
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element.nodes[j],
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&mut edge_midpoints,
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&mut refined_mesh,
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mesh,
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);
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edge_mids.push(mid);
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}
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// Create face centers (6 faces)
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let face_indices = [
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[0, 1, 2, 3], // Bottom
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[4, 5, 6, 7], // Top
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[0, 1, 5, 4], // Front
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[2, 3, 7, 6], // Back
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[0, 3, 7, 4], // Left
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[1, 2, 6, 5], // Right
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];
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let mut face_centers = Vec::new();
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for face in &face_indices {
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let mut center = nalgebra::DVector::zeros(mesh.spatial_dimension);
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for &idx in face {
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center += &mesh.nodes[&element.nodes[idx]].coordinates;
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}
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center /= 4.0;
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let face_node = Node {
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coordinates: center,
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dofs: mesh.nodes[&element.nodes[0]].dofs.clone(),
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label: None,
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};
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face_centers.push(refined_mesh.add_node(face_node));
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}
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// Create volume center
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let mut vol_center = nalgebra::DVector::zeros(mesh.spatial_dimension);
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for &node_id in &element.nodes {
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vol_center += &mesh.nodes[&node_id].coordinates;
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}
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vol_center /= 8.0;
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let vol_center_node = Node {
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coordinates: vol_center,
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dofs: mesh.nodes[&element.nodes[0]].dofs.clone(),
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label: None,
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};
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let vol_center_id = refined_mesh.add_node(vol_center_node);
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// Create 8 new hexahedra
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// This is complex - each original vertex gets a new hex
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let new_hex_nodes = [
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// Hex at vertex 0
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vec![
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original_nodes[0],
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edge_mids[0],
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face_centers[0],
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edge_mids[3],
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edge_mids[8],
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face_centers[2],
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vol_center_id,
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face_centers[4],
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],
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// Hex at vertex 1
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vec![
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edge_mids[0],
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original_nodes[1],
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edge_mids[1],
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face_centers[0],
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face_centers[2],
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edge_mids[9],
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face_centers[5],
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vol_center_id,
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],
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// Hex at vertex 2
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vec![
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face_centers[0],
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edge_mids[1],
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original_nodes[2],
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edge_mids[2],
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vol_center_id,
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face_centers[5],
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edge_mids[10],
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face_centers[3],
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],
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// Hex at vertex 3
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vec![
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edge_mids[3],
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face_centers[0],
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edge_mids[2],
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original_nodes[3],
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face_centers[4],
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vol_center_id,
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face_centers[3],
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edge_mids[11],
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],
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// Hex at vertex 4
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vec![
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edge_mids[8],
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face_centers[2],
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vol_center_id,
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face_centers[4],
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original_nodes[4],
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edge_mids[4],
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face_centers[1],
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edge_mids[7],
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],
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// Hex at vertex 5
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vec![
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face_centers[2],
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edge_mids[9],
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face_centers[5],
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vol_center_id,
|
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edge_mids[4],
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original_nodes[5],
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edge_mids[5],
|
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face_centers[1],
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],
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// Hex at vertex 6
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vec![
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vol_center_id,
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face_centers[5],
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edge_mids[10],
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face_centers[3],
|
||||
face_centers[1],
|
||||
edge_mids[5],
|
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original_nodes[6],
|
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edge_mids[6],
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],
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// Hex at vertex 7
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vec![
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face_centers[4],
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vol_center_id,
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face_centers[3],
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edge_mids[11],
|
||||
edge_mids[7],
|
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face_centers[1],
|
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edge_mids[6],
|
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original_nodes[7],
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],
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];
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for nodes in &new_hex_nodes {
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refined_mesh.add_element(Element::new(
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ElementType::Hex8,
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nodes.clone(),
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element.material_id,
|
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)?);
|
||||
}
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||||
}
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||||
|
||||
_ => {
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||||
// For other element types, just copy as-is
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||||
refined_mesh.add_element(element.clone());
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||||
}
|
||||
}
|
||||
}
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Ok(refined_mesh)
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||||
}
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||||
|
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/// Adaptive refinement based on error indicators.
|
||||
pub fn adaptive_refinement(
|
||||
mesh: &crate::mesh::Mesh,
|
||||
error_indicators: &HashMap<crate::mesh::ElementId, f64>,
|
||||
threshold: f64,
|
||||
) -> FeaResult<crate::mesh::Mesh> {
|
||||
let mut refined_mesh = crate::mesh::Mesh::new(mesh.spatial_dimension)?;
|
||||
|
||||
// Copy all nodes first
|
||||
let mut node_mapping = HashMap::new();
|
||||
for (node_id, node) in &mesh.nodes {
|
||||
let new_node = Node {
|
||||
coordinates: node.coordinates.clone(),
|
||||
dofs: node.dofs.clone(),
|
||||
label: node.label.clone(),
|
||||
};
|
||||
let new_id = refined_mesh.add_node(new_node);
|
||||
node_mapping.insert(*node_id, new_id);
|
||||
}
|
||||
|
||||
// Track edge midpoints
|
||||
let mut edge_midpoints: HashMap<(NodeId, NodeId), NodeId> = HashMap::new();
|
||||
|
||||
// Process each element based on error indicator
|
||||
for (element_id, element) in &mesh.elements {
|
||||
let error = error_indicators.get(element_id).copied().unwrap_or(0.0);
|
||||
|
||||
if error > threshold {
|
||||
// Refine this element
|
||||
// For simplicity, use uniform refinement logic per element
|
||||
// In practice, this would be more sophisticated
|
||||
if element.element_type == ElementType::Tri3 {
|
||||
// Triangle refinement (same as uniform case)
|
||||
let n0 = node_mapping[&element.nodes[0]];
|
||||
let n1 = node_mapping[&element.nodes[1]];
|
||||
let n2 = node_mapping[&element.nodes[2]];
|
||||
|
||||
// Helper to get/create midpoint
|
||||
let mut get_mid = |i: usize, j: usize| -> NodeId {
|
||||
let ni = element.nodes[i];
|
||||
let nj = element.nodes[j];
|
||||
let key = if ni < nj { (ni, nj) } else { (nj, ni) };
|
||||
|
||||
*edge_midpoints.entry(key).or_insert_with(|| {
|
||||
let mid_coords = (&mesh.nodes[&ni].coordinates
|
||||
+ &mesh.nodes[&nj].coordinates)
|
||||
* 0.5;
|
||||
let mid_node = Node {
|
||||
coordinates: mid_coords,
|
||||
dofs: mesh.nodes[&ni].dofs.clone(),
|
||||
label: None,
|
||||
};
|
||||
refined_mesh.add_node(mid_node)
|
||||
})
|
||||
};
|
||||
|
||||
let m01 = get_mid(0, 1);
|
||||
let m12 = get_mid(1, 2);
|
||||
let m20 = get_mid(2, 0);
|
||||
|
||||
// Create 4 refined triangles
|
||||
refined_mesh.add_element(Element::new(
|
||||
ElementType::Tri3,
|
||||
vec![n0, m01, m20],
|
||||
element.material_id,
|
||||
)?);
|
||||
refined_mesh.add_element(Element::new(
|
||||
ElementType::Tri3,
|
||||
vec![m01, n1, m12],
|
||||
element.material_id,
|
||||
)?);
|
||||
refined_mesh.add_element(Element::new(
|
||||
ElementType::Tri3,
|
||||
vec![m20, m12, n2],
|
||||
element.material_id,
|
||||
)?);
|
||||
refined_mesh.add_element(Element::new(
|
||||
ElementType::Tri3,
|
||||
vec![m01, m12, m20],
|
||||
element.material_id,
|
||||
)?);
|
||||
} else {
|
||||
// For other element types or below threshold, copy as-is
|
||||
let new_nodes: Vec<_> =
|
||||
element.nodes.iter().map(|&n| node_mapping[&n]).collect();
|
||||
refined_mesh.add_element(Element::new(
|
||||
element.element_type,
|
||||
new_nodes,
|
||||
element.material_id,
|
||||
)?);
|
||||
}
|
||||
} else {
|
||||
// Copy element without refinement
|
||||
let new_nodes: Vec<_> = element.nodes.iter().map(|&n| node_mapping[&n]).collect();
|
||||
refined_mesh.add_element(Element::new(
|
||||
element.element_type,
|
||||
new_nodes,
|
||||
element.material_id,
|
||||
)?);
|
||||
}
|
||||
}
|
||||
|
||||
Ok(refined_mesh)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user