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JuliaFEM.jl/test/basis/test_numerical_accuracy.jl
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Jukka Aho f3861b4f84 test(basis): add test_numerical_accuracy test
Test file included in test/basis/runtests.jl
2025-12-15 06:32:29 +02:00

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Julia

# Test that numerical filtering produces clean fractions
# Verify the improved round_coefficient function works correctly
using Test
using StaticArrays, Tensors
include("../../src/topology/api.jl")
include("../../src/topology/segments.jl")
include("../../src/topology/triangles.jl")
include("../../src/topology/quadrilaterals.jl")
include("../../src/topology/tetrahedra.jl")
include("../../src/topology/hexahedra.jl")
include("../../src/topology/pyramids.jl")
include("../../src/topology/wedges.jl")
include("../../src/basis/api.jl")
include("../../src/basis/basis_generated.jl")
@testset "Numerical Accuracy - Clean Fractions" begin
@testset "Hex27 corner nodes - 1/18 coefficients" begin
# At origin, all corner nodes should have specific fraction contributions
N = get_basis_functions(Hex27(), Lagrange{2}(), Vec{3}((0.0, 0.0, 0.0)))
# The linear terms in corner shape functions should be exactly 1/18
# We can't test the internal expression, but we can verify the partition of unity
@test sum(N) 1.0 atol = 1e-14
@test length(N) == 27
# Center node (N27) should be 1 at center
@test N[27] 1.0 atol = 1e-14
# All other nodes should be 0 at center
@test all(N[1:26] .≈ 0.0)
end
@testset "Hex27 mid-edge nodes - 5/18 coefficients" begin
# At a mid-edge location, verify partition of unity
N = get_basis_functions(Hex27(), Lagrange{2}(), Vec{3}((0.5, 0.0, 0.0)))
@test sum(N) 1.0 atol = 1e-14
end
@testset "Common fractions in all elements" begin
# Test that basis functions evaluate without numerical noise
# 1/2 (Seg2)
N = get_basis_functions(Seg2(), Lagrange{1}(), Vec{1}((0.0,)))
@test N[1] 0.5 atol = 1e-14
@test N[2] 0.5 atol = 1e-14
# 1/3 (Tri3 at centroid)
N = get_basis_functions(Tri3(), Lagrange{1}(), Vec{2}((1 / 3, 1 / 3)))
@test N[1] 1 / 3 atol = 1e-14
@test N[2] 1 / 3 atol = 1e-14
@test N[3] 1 / 3 atol = 1e-14
# 1/4 (Quad4 at center)
N = get_basis_functions(Quad4(), Lagrange{1}(), Vec{2}((0.0, 0.0)))
@test all(N .≈ 0.25)
# 1/8 (Hex8 at center)
N = get_basis_functions(Hex8(), Lagrange{1}(), Vec{3}((0.0, 0.0, 0.0)))
@test all(N .≈ 0.125)
end
@testset "Higher-order elements - no numerical noise" begin
# Quad9 at various points
N = get_basis_functions(Quad9(), Lagrange{2}(), Vec{2}((0.3, 0.7)))
@test sum(N) 1.0 atol = 1e-14
@test !any(isnan, N)
@test !any(isinf, N)
# Tet10 at various points
N = get_basis_functions(Tet10(), Lagrange{2}(), Vec{3}((0.1, 0.2, 0.3)))
@test sum(N) 1.0 atol = 1e-14
@test !any(isnan, N)
@test !any(isinf, N)
# Hex20 at various points (uses Serendipity basis)
N = get_basis_functions(Hex20(), Serendipity{2}(), Vec{3}((-0.5, 0.5, 0.0)))
@test sum(N) 1.0 atol = 1e-14
@test !any(isnan, N)
@test !any(isinf, N)
end
end