mirror of
https://github.com/JuliaFEM/JuliaFEM.jl.git
synced 2026-10-01 05:49:22 +00:00
Jukka Aho
2afd7a856a
Move struct definitions to dof_connectivity_types.jl; drop GPU matrix layout; use DOFHandler in docs and convenience build_dof_connectivity overload.
105 lines
3.6 KiB
Julia
105 lines
3.6 KiB
Julia
# This file is a part of JuliaFEM.
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# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
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"""
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DOF connectivity builders for DOF-based assembly.
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Provides inverse mapping: DOF → Elements (which elements touch each DOF).
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GPU-Compatible: Uses bits types defined in `dof_connectivity_types.jl`.
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Zero-Allocation: After initialization, all operations are allocation-free.
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"""
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# Import element and DOF handler interfaces (defined in elements.jl and dof_handler.jl)
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using ..JuliaFEM: element_dofs, DOFHandler
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# ============================================================================
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# DOF CONNECTIVITY BUILDERS
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# ============================================================================
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"""
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build_dof_connectivity(elements, n_total_dofs) -> DOFConnectivity
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build_dof_connectivity(elements, dof_handler::DOFHandler) -> DOFConnectivity
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Build the DOF→element inverse mapping in a single pass over `elements`.
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Complexity is `O(n_elements × dofs_per_element)`. After construction the
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returned `DOFConnectivity` supports zero-allocation iteration through
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`dof_to_elements[dof_i]`. The `DOFHandler` overload is a thin convenience
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that forwards `dof_handler.total_dofs`.
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# Example
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```julia
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S = @DOFSet{u::DOF{Displacement{3}, Vertex}}
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ElemType = Element{Tetrahedron{4}, Lagrange{1}, S}
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elements, handler = create_elements!(mesh, ElemType)
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connectivity = build_dof_connectivity(elements, handler)
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for dof_i in 1:connectivity.n_total_dofs
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for conn in connectivity.dof_to_elements[dof_i]
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elem = elements[conn.elem_id]
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local_dof = conn.local_dof_idx
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# ...
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end
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end
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```
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"""
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function build_dof_connectivity(elements::Vector, n_total_dofs::Integer)
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n_total_dofs = Int(n_total_dofs)
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if n_total_dofs == 0
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return DOFConnectivity(Vector{DOFElementConnection}[], 0)
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end
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# One bucket per DOF. Pre-size each to the typical 3D fan-in (~6 elements
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# per DOF) so the inner push! loop avoids most reallocations.
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dof_to_elements = [DOFElementConnection[] for _ in 1:n_total_dofs]
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avg_connections = 6
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for vec in dof_to_elements
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sizehint!(vec, avg_connections)
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end
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for (elem_id, elem) in enumerate(elements)
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dofs = element_dofs(elem) # NTuple{N, UInt64}
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for (local_idx, global_dof) in enumerate(dofs)
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if global_dof < 1 || global_dof > n_total_dofs
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error("Invalid global DOF index $global_dof (must be in [1, $n_total_dofs])")
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end
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push!(dof_to_elements[global_dof], DOFElementConnection(elem_id, local_idx))
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end
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end
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return DOFConnectivity(dof_to_elements, n_total_dofs)
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end
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# Convenience overload: pull `n_total_dofs` straight from a DOFHandler so
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# callers do not have to thread it through.
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build_dof_connectivity(elements::Vector, dof_handler::DOFHandler) =
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build_dof_connectivity(elements, dof_handler.total_dofs)
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# ============================================================================
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# UTILITY FUNCTIONS
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# ============================================================================
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"""
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connection_count(connectivity::DOFConnectivity, dof_i::Int) -> Int
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Get number of elements touching DOF i.
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Zero-allocation: Direct array length access.
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"""
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@inline connection_count(connectivity::DOFConnectivity, dof_i::Int) =
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length(connectivity.dof_to_elements[dof_i])
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"""
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is_empty(connectivity::DOFConnectivity, dof_i::Int) -> Bool
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Check if DOF i has no connections.
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Zero-allocation: Direct array length check.
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"""
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@inline is_empty(connectivity::DOFConnectivity, dof_i::Int) =
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isempty(connectivity.dof_to_elements[dof_i])
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# Exports for these types live in `src/exports.jl`.
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