mirror of
https://github.com/JuliaFEM/JuliaFEM.jl.git
synced 2026-08-05 20:11:31 +00:00
Jukka Aho
239 lines
9.3 KiB
Julia
239 lines
9.3 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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Regression test: DOF-based assembler must stay zero-allocation
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and bit-equivalent to the element-based assembler.
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This test exists to lock in the December 2025 zero-allocation work
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and to catch any regression as the assembler evolves.
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Each problem size:
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1. Build a structured Hex8 / Tet4 mesh
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2. Create elements + DOFManager
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3. Build both assemblers
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4. Warm up
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5. Assert: 0 bytes allocated by the DOF-based `assemble!`
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6. Assert: matrix matches the element-based assembler to round-off
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"""
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using Test
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using JuliaFEM
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using JuliaFEM: DOFBasedCOOAssembler, DOFBasedCOOCache
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using JuliaFEM: COOAssembler, create_cache
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using JuliaFEM: create_elements!, @DOFSet, DOF, Displacement, Vertex
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using JuliaFEM: local_dof_layout, DOFLayoutEntry
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using LinearAlgebra
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using SparseArrays
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using Tensors
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using InteractiveUtils # @code_typed, code_llvm
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# ----------------------------------------------------------------------------
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# Helpers (kept local to this test, no leak into package)
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# ----------------------------------------------------------------------------
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"""
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Build a structured Hex8 box mesh with `nx × ny × nz` elements over [0,1]^3.
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"""
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function _build_hex8_box_mesh(nx::Int, ny::Int, nz::Int)
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nodes = Vec{3,Float64}[]
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nidx(i, j, k) = (i - 1) + (j - 1) * (nx + 1) + (k - 1) * (nx + 1) * (ny + 1) + 1
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for k in 1:(nz + 1), j in 1:(ny + 1), i in 1:(nx + 1)
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push!(nodes, Vec{3}((Float64(i - 1) / nx,
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Float64(j - 1) / ny,
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Float64(k - 1) / nz)))
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end
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conns = NTuple{8,UInt32}[]
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for k in 1:nz, j in 1:ny, i in 1:nx
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n1 = nidx(i, j, k)
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n2 = nidx(i + 1, j, k)
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n3 = nidx(i + 1, j + 1, k)
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n4 = nidx(i, j + 1, k)
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n5 = nidx(i, j, k + 1)
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n6 = nidx(i + 1, j, k + 1)
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n7 = nidx(i + 1, j + 1, k + 1)
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n8 = nidx(i, j + 1, k + 1)
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push!(conns, (UInt32(n1), UInt32(n2), UInt32(n3), UInt32(n4),
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UInt32(n5), UInt32(n6), UInt32(n7), UInt32(n8)))
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end
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return Mesh{8,Hexahedron{8}}(nodes, conns)
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end
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"""
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Build a single Tet4 mesh.
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"""
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function _build_single_tet4_mesh()
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nodes = Vec{3,Float64}[
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Vec{3}((0.0, 0.0, 0.0)),
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Vec{3}((1.0, 0.0, 0.0)),
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Vec{3}((0.5, 1.0, 0.0)),
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Vec{3}((0.5, 0.5, 1.0)),
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]
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conns = [(UInt32(1), UInt32(2), UInt32(3), UInt32(4))]
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return Mesh{Tetrahedron{4}}(nodes, conns)
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end
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"""
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Setup elasticity assembly fixture for a given mesh + topology.
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Returns (cache_dof, asm_dof, cache_elem, asm_elem, kernel, mesh).
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"""
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function _setup_assembly(mesh, ::Type{Topo}) where {Topo}
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material = LinearElastic(E = 210e9, ν = 0.3)
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kernel = ContinuumKernel(ContinuumFormulation{FullThreeD}(),
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material, Displacement{3}())
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S = @DOFSet{u::DOF{Displacement{3}, Vertex}}
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elements, dof_mgr = create_elements!(mesh, Element{Topo, Lagrange{1}, S})
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asm_dof = DOFBasedCOOAssembler()
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cache_dof = DOFBasedCOOCache(elements, dof_mgr, mesh, kernel)
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asm_elem = COOAssembler()
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cache_elem = create_cache(asm_elem, mesh, kernel)
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return cache_dof, asm_dof, cache_elem, asm_elem, kernel, mesh
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end
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# ----------------------------------------------------------------------------
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# Tests
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# ----------------------------------------------------------------------------
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@testset "DOF-based assembler: zero allocation regression" begin
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println("\n" * "=" ^ 70)
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println("DOF-BASED ASSEMBLER ZERO-ALLOCATION REGRESSION")
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println("=" ^ 70)
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# ------------------------------------------------------------------------
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# 1. Single Tet4
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# ------------------------------------------------------------------------
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@testset "Single Tet4" begin
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mesh = _build_single_tet4_mesh()
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cache_dof, asm_dof, cache_elem, asm_elem, kernel, m =
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_setup_assembly(mesh, Tetrahedron{4})
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# warmup
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assemble!(cache_dof, asm_dof, kernel, m)
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assemble!(cache_elem, asm_elem, kernel, m)
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K_dof, _ = extract_system(cache_dof)
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K_elem, _ = extract_system(cache_elem)
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# Equivalence
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rel = maximum(abs, Matrix(K_dof) - Matrix(K_elem)) /
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max(maximum(abs, Matrix(K_elem)), 1.0)
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@test rel < 1e-12
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# Zero-alloc
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GC.gc()
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a = @allocated assemble!(cache_dof, asm_dof, kernel, m)
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@test a == 0
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println(" Single Tet4 ........................ allocs=$a, rel=$(round(rel; sigdigits=3))")
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end
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# ------------------------------------------------------------------------
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# 2. Growing Hex8 cube meshes
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# ------------------------------------------------------------------------
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@testset "Hex8 cube $(nx)×$(ny)×$(nz)" for (nx, ny, nz) in
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[(1, 1, 1), (2, 1, 1), (4, 2, 2), (6, 3, 3), (8, 4, 4)]
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mesh = _build_hex8_box_mesh(nx, ny, nz)
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cache_dof, asm_dof, cache_elem, asm_elem, kernel, m =
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_setup_assembly(mesh, Hexahedron{8})
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# warmup
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assemble!(cache_dof, asm_dof, kernel, m)
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assemble!(cache_elem, asm_elem, kernel, m)
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K_dof, _ = extract_system(cache_dof)
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K_elem, _ = extract_system(cache_elem)
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rel = maximum(abs, Matrix(K_dof) - Matrix(K_elem)) /
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max(maximum(abs, Matrix(K_elem)), 1.0)
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@test rel < 1e-12
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GC.gc()
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a = @allocated assemble!(cache_dof, asm_dof, kernel, m)
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@test a == 0
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nelems = length(m.connectivity)
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ndofs = 3 * length(m.nodes)
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println(" Hex8 $(nx)×$(ny)×$(nz) $(lpad(nelems,5)) elem " *
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"$(lpad(ndofs,5)) dof allocs=$a rel=$(round(rel; sigdigits=3))")
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end
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end
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# ----------------------------------------------------------------------------
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# Type stability check (no untyped ::Any in inferred output)
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# ----------------------------------------------------------------------------
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@testset "DOF-based assembler: type stability" begin
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mesh = _build_hex8_box_mesh(2, 1, 1)
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cache_dof, asm_dof, _, _, kernel, m = _setup_assembly(mesh, Hexahedron{8})
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assemble!(cache_dof, asm_dof, kernel, m) # warmup
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# Inferred return type must be concrete (Nothing).
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rt = Base.promote_op(assemble!, typeof(cache_dof), typeof(asm_dof),
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typeof(kernel), typeof(m))
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@test rt === Nothing
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# No method ambiguities or `Any` in the top-level signature
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code = code_typed(assemble!, (typeof(cache_dof), typeof(asm_dof),
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typeof(kernel), typeof(m)); optimize = true)
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@test !isempty(code)
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info = code[1]
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@test isconcretetype(info.second)
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println(" assemble! inferred return type: $(info.second)")
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end
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# ----------------------------------------------------------------------------
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# Element-as-template: local_dof_layout(E) is compile-time constant and
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# `assemble!` has zero GC allocation sites in the optimized LLVM IR.
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# ----------------------------------------------------------------------------
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@testset "DOF-based assembler: element template + LLVM allocs" begin
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mesh = _build_hex8_box_mesh(2, 1, 1)
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cache_dof, asm_dof, _, _, kernel, m = _setup_assembly(mesh, Hexahedron{8})
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assemble!(cache_dof, asm_dof, kernel, m) # warmup
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# ------------------------------------------------------------------
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# 1. local_dof_layout returns the expected NTuple of DOFLayoutEntry
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# for an Hex8 displacement element (24 DOFs, 8 vertices × 3 comp.)
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# ------------------------------------------------------------------
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ET = eltype(cache_dof.elements)
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layout = local_dof_layout(ET)
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@test layout isa NTuple{24, DOFLayoutEntry}
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@test all(e -> e.field_idx == 1, layout)
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@test [Int(e.entity_local) for e in layout] ==
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repeat(1:8; inner = 3)
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@test [Int(e.component) for e in layout] ==
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repeat(1:3, 8)
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# ------------------------------------------------------------------
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# 2. local_dof_layout(ET) call is constant-folded by the compiler:
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# @allocated must be 0 and the optimized typed-IR must report a
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# `Core.Const` for the layout in `assemble!` — exercised already
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# by the zero-allocation tests above. We assert separately here.
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# ------------------------------------------------------------------
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GC.gc()
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a_layout = @allocated local_dof_layout(ET)
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@test a_layout == 0
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# ------------------------------------------------------------------
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# 3. Optimized LLVM IR for `assemble!` must have ZERO GC allocation
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# sites. This is the strongest guarantee: even if @allocated == 0
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# today, this catches any future change that would re-introduce
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# a heap-allocating call inside the inner loop.
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# ------------------------------------------------------------------
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iob = IOBuffer()
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code_llvm(iob, assemble!,
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Tuple{typeof(cache_dof), typeof(asm_dof),
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typeof(kernel), typeof(m)}; optimize = true)
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ir = String(take!(iob))
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n_alloc =
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length(collect(eachmatch(r"call.*julia\.gc_alloc", ir))) +
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length(collect(eachmatch(r"call.*jl_gc_pool_alloc", ir))) +
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length(collect(eachmatch(r"call.*jl_gc_big_alloc", ir))) +
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length(collect(eachmatch(r"call.*jl_gc_alloc_typed", ir)))
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@test n_alloc == 0
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println(" assemble! optimized LLVM IR: $n_alloc gc-alloc sites " *
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"($(length(ir)) IR chars)")
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end
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