JuliaFEM.jl/src/mesh

src/mesh/

Mesh data structures, mesh generation utilities and a few graph-level optimisations used by the rest of the package.

Files

• api.jl — AbstractMesh, AbstractRefineStrategy and the abstract interface (nnodes_total, nelements, get_node, connectivity_matrix, get_node_set, get_element_set, …).
• mesh.jl — concrete Mesh{N, T<:AbstractTopology{N}} type, constructors with validation, the inverse connectivity (node -> elements) needed by node-based assembly, helpers for sets and surface extraction.
• structured.jl — create_structured_box_mesh, create_unit_cube_mesh, create_cantilever_mesh, create_thin_plate_mesh. Boundary node sets are populated automatically (:xmin, :xmax, …).
• refine.jl — LongestEdgeBisection and the refine entry point. Used for h-convergence studies.

Type-stable mesh

Mesh{N, T<:AbstractTopology{N}}

N is the number of nodes per element and T is the element topology. Concrete instances such as Mesh{8, Hex8} carry no abstract fields, so the assembly hot path can be fully inferred. The mesh stores

• nodes::Vector{Vec{3, Float64}} — coordinates (always 3D; 2D problems use z = 0),
• connectivity::Vector{NTuple{N, UInt32}} — fixed-size connectivity,
• element_sets::Dict{Symbol, Set{UInt32}},
• node_sets::Dict{Symbol, Set{UInt32}},
• inverse_connectivity::Vector{Vector{Tuple{UInt32, UInt8}}} — populated lazily; needed by node-based assembly.

Common usage

mesh = create_structured_box_mesh(Hex8;
    xmin = 0.0, xmax = 1.0, nx = 4,
    ymin = 0.0, ymax = 1.0, ny = 4,
    zmin = 0.0, zmax = 1.0, nz = 4,
)

n_nodes = nnodes_total(mesh)
n_elems = nelements(mesh)

X       = get_node(mesh, 42)
fixed   = get_node_set(mesh, :xmin)
body    = get_element_set(mesh, :body)
elem_xs = get_elements_for_node(mesh, node_id)

Refinement

refined = refine(mesh, LongestEdgeBisection(3))

LongestEdgeBisection(levels) performs adaptive bisection along the longest edge of each element, doubling the element count per level.

I/O

Mesh import lives in src/io/ (currently the self-contained Gmsh reader). VTK / XDMF output is not implemented in the new path; the legacy results writers under src/legacy/ cover existing tests.

Related code

• src/topology/ — element topologies referenced by Mesh{N,T}.
• src/dofs/ — the DOF handler walks the mesh to assign global DOF numbers.
• src/assemblers/ — element-based and DOF-based assembly both consume the mesh and its inverse connectivity.
• test/ — mesh-level coverage rides on the active domain test suites (test/domains/, test/assemblers/); the legacy parallel/coloring/RCM tests live at llm/design/legacy-tests/mesh/.