compute returns SparseVector

src/assembler/assembler.jl

@@ -734,17 +734,18 @@ Base.repeat(a::SVector, ::Val{N}) where {N} = reduce(vcat, ntuple(i -> a, Val(N)
 
 Compute an integral, independently from a FEM/DG framework (i.e without FESpace)
 
-Return a dict (same size of the domain of integration) <elt mesh-index> => <integral evaluated over the elt>.
+Return a `SparseVector`. The indices of the domain elements are used to store
+the result of the integration in this sparse vector.
 
 # Example
 Compute volume of each cell and each face.
 ```julia
 mesh = rectangle_mesh(2, 3)
 dΩ = Measure(CellDomain(mesh), 1)
-∂Ω = Measure(BoundaryFaceDomain(mesh), 1)
+dΓ = Measure(BoundaryFaceDomain(mesh), 1)
 f = PhysicalFunction(x -> 1)
 @show Bcube.compute(∫(f)dΩ)
-@show Bcube.compute(∫(side⁻(f))∂Ω)
+@show Bcube.compute(∫(side⁻(f))dΓ)
 ```
 """
 function compute(integration::Integration)
@@ -758,9 +759,12 @@ function compute(integration::Integration)
         _integrate_on_ref_element(_f, elementInfo, quadrature)
     end
 
-    return Dict(indices(domain) .=> values)
+    return SparseVector(_domain_to_mesh_nelts(domain), collect(indices(domain)), values)
 end
 
+_domain_to_mesh_nelts(domain::AbstractCellDomain) = ncells(get_mesh(domain))
+_domain_to_mesh_nelts(domain::AbstractFaceDomain) = nfaces(get_mesh(domain))
+
 """
     AbstractFaceSidePair{A} <: AbstractLazyWrap{A}
 

test/Project.toml

@@ -5,4 +5,5 @@ StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
 SHA = "ea8e919c-243c-51af-8825-aaa63cd721ce"
-ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"

test/dof/test_assembler.jl

@@ -264,8 +264,8 @@
         sys = Bcube.AffineFESystem(a, l, U, V)
         uh = Bcube.solve(sys)
 
-        l2(u) = sqrt(sum(values(compute(∫(u ⋅ u)dΩ))))
-        h1(u) = sqrt(sum(values(compute(∫(u ⋅ u + ∇(u) ⋅ ∇(u))dΩ))))
+        l2(u) = sqrt(sum(compute(∫(u ⋅ u)dΩ)))
+        h1(u) = sqrt(sum(compute(∫(u ⋅ u + ∇(u) ⋅ ∇(u))dΩ)))
         e = uref - uh
 
         el2 = l2(e)
@@ -313,7 +313,7 @@
 
         int_val = 4.0 / 3.0
 
-        volume = sum(values(compute(∫(PhysicalFunction(x -> 1.0))dΩ)))
+        volume = sum(compute(∫(PhysicalFunction(x -> 1.0))dΩ))
 
         # Define bilinear and linear forms
         function a((u, λᵤ), (v, λᵥ))
@@ -339,7 +339,7 @@
         u_ref = PhysicalFunction(x -> -0.5 * (x[1] - 1.0)^2 + 1.0)
         error = u_ref - u
 
-        l2(u) = sqrt(sum(values(compute(∫(u ⋅ u)dΩ))))
+        l2(u) = sqrt(sum(compute(∫(u ⋅ u)dΩ)))
         el2 = l2(error)
         tol = 1.e-15
         @test el2 < tol

test/integration/test_integration.jl

@@ -381,7 +381,7 @@ end
         Γ = BoundaryFaceDomain(mesh, "boundary")
         dΓ = Measure(Γ, 2)
         nΓ = get_face_normals(dΓ)
-        val = sum(values(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ)))
+        val = sum(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ))
         @test isapprox(val, 0.0, atol = 1e-15)
     end
 
@@ -420,7 +420,7 @@ end
         Γ = BoundaryFaceDomain(mesh, "boundary")
         dΓ = Measure(Γ, 2)
         nΓ = get_face_normals(dΓ)
-        val = sum(values(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ)))
+        val = sum(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ))
         @test isapprox(val, 0.0, atol = 1e-14)
     end
 
@@ -463,15 +463,15 @@ end
         Γ = BoundaryFaceDomain(mesh, "boundary")
         dΓ = Measure(Γ, 2)
         nΓ = get_face_normals(dΓ)
-        val = sum(values(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ)))
+        val = sum(compute(∫(side_n(u) ⋅ side_n(nΓ))dΓ))
         @test isapprox(val, 0.0, atol = 1e-15)
     end
 
     @testset "PhysicalFunction" begin
         mesh = translate(one_cell_mesh(:line), [1.0])
         dΩ = Measure(CellDomain(mesh), 2)
         g = PhysicalFunction(x -> 2 * x[1])
-        b = collect(values(compute(∫(g)dΩ)))
+        b = compute(∫(g)dΩ)
         @test b[1] == 4.0
     end
 
@@ -521,10 +521,10 @@ end
         @test Bcube.integrate(x -> 1, ctype, cnodes, Quadrature(1)) ≈ 4
         dΩ = Measure(CellDomain(mesh), 2)
         g = PhysicalFunction(x -> 1)
-        b = collect(values(compute(∫(g)dΩ)))
+        b = compute(∫(g)dΩ)
         @test b[1] ≈ 4
         gref = ReferenceFunction(x -> 1)
-        b = collect(values(compute(∫(gref)dΩ)))
+        b = compute(∫(gref)dΩ)
         @test b[1] ≈ 4
 
         lx = 2.0
@@ -548,8 +548,9 @@ end
         surface_ref = (s(-e12, e23), s(-e12, e24), s(e24, e23), s(e13, e14))
         for i in 1:4
             dΓ = Measure(BoundaryFaceDomain(mesh, "F$i"), 1)
-            b = collect(values(compute(∫(side⁻(g))dΓ)))
-            @test b[1] ≈ surface_ref[i]
+            b = compute(∫(side⁻(g))dΓ)
+            I, = findnz(b)
+            @test b[I[1]] ≈ surface_ref[i]
         end
     end
 
@@ -571,7 +572,7 @@ end
         @test Bcube.integrate(x -> 1, ctype, cnodes, Quadrature(1)) == 0.75
         dΩ = Measure(CellDomain(mesh), 2)
         g = PhysicalFunction(x -> 1)
-        b = collect(values(compute(∫(g)dΩ)))
+        b = compute(∫(g)dΩ)
         @test b[1] ≈ 0.75
 
         # Whole cylinder : build a cylinder of radius 1 and length 1, and compute its volume
@@ -581,7 +582,7 @@ end
 
         dΩ = Measure(CellDomain(mesh), 2)
         g = PhysicalFunction(x -> 1)
-        b = values(compute(∫(g)dΩ))
+        b = compute(∫(g)dΩ)
         @test sum(b) ≈ 3.1365484905459
     end
 end

test/operator/test_algebra.jl

@@ -55,8 +55,7 @@
         translate!(mesh, SA[-0.5, 1.0]) # the translation vector can be anything
         scale!(mesh, 2.0)
         dΩ = Measure(CellDomain(mesh), 1)
-        @test collect(values(compute(∫(∇(PhysicalFunction(x -> x[1])) ⋅ [1, 1])dΩ)))[1] ==
-              16.0
+        @test compute(∫(∇(PhysicalFunction(x -> x[1])) ⋅ [1, 1])dΩ)[1] == 16.0
 
         # Gradient of a vector PhysicalFunction
         mesh = one_cell_mesh(:quad)

test/runtests.jl

@@ -5,6 +5,7 @@ using LinearAlgebra
 using DelimitedFiles
 using ForwardDiff
 using SHA: sha1
+using SparseArrays
 
 # from :
 # https://discourse.julialang.org/t/what-general-purpose-commands-do-you-usually-end-up-adding-to-your-projects/4889