Gauss-Legendre on 1D periodic StructuredMesh

src/solvers/dgsem_structured/containers_1d.jl

@@ -6,7 +6,7 @@
 #! format: noindent
 
 # Initialize data structures in element container
-function init_elements!(elements, mesh::StructuredMesh{1}, basis::LobattoLegendreBasis)
+function init_elements!(elements, mesh::StructuredMesh{1}, basis::AbstractBasisSBP)
     @unpack node_coordinates, left_neighbors,
     jacobian_matrix, contravariant_vectors, inverse_jacobian = elements
 
@@ -31,7 +31,7 @@ end
 # `mesh.mapping` is passed as an additional argument for type stability (function barrier)
 function calc_node_coordinates!(node_coordinates, cell_x, mapping,
                                 mesh::StructuredMesh{1},
-                                basis::LobattoLegendreBasis)
+                                basis::AbstractBasisSBP)
     @unpack nodes = basis
 
     # Get cell length in reference mesh
@@ -51,7 +51,7 @@ end
 # Calculate Jacobian matrix of the mapping from the reference element to the element in the physical domain
 function calc_jacobian_matrix!(jacobian_matrix, element,
                                node_coordinates::AbstractArray{<:Any, 3},
-                               basis::LobattoLegendreBasis)
+                               basis::AbstractBasisSBP)
     @views mul!(jacobian_matrix[1, 1, :, element], basis.derivative_matrix,
                 node_coordinates[1, :, element]) # x_ξ
 

src/solvers/dgsem_structured/dg_1d.jl

@@ -22,6 +22,32 @@ function prolong2interfaces!(cache, u, mesh::StructuredMesh{1}, equations, dg::D
     return nothing
 end
 
+function prolong2interfaces!(cache, u, mesh::StructuredMesh{1}, equations,
+                             dg::DGSEM{<:GaussLegendreBasis})
+    @unpack interfaces_u = cache.elements
+    @unpack boundary_interpolation = dg.basis
+
+    @threaded for element in eachelement(dg, cache)
+        for v in eachvariable(equations)
+            interface_u_1 = zero(eltype(interfaces_u))
+            interface_u_2 = zero(eltype(interfaces_u))
+            for i in eachnode(dg)
+                # Left/negative x face
+                interface_u_1 = interface_u_1 +
+                                u[v, i, element] * boundary_interpolation[i, 1]
+
+                # Right/positive x face
+                interface_u_2 = interface_u_2 +
+                                u[v, i, element] * boundary_interpolation[i, 2]
+            end
+            interfaces_u[v, 1, element] = interface_u_1
+            interfaces_u[v, 2, element] = interface_u_2
+        end
+    end
+
+    return nothing
+end
+
 function calc_interface_flux!(surface_flux_values, mesh::StructuredMesh{1},
                               nonconservative_terms, # can be True/False
                               equations, surface_integral, dg::DG, cache)

test/test_structured_1d.jl

@@ -24,6 +24,19 @@ isdir(outdir) && rm(outdir, recursive = true)
     @test_allocations(Trixi.rhs!, semi, sol, 1000)
 end
 
+@trixi_testset "elixir_advection_basic.jl (Gauss-Legendre)" begin
+    @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_basic.jl"),
+                        solver=DGSEM(polydeg = 3, basis_type = GaussLegendreBasis,
+                                     surface_flux = flux_godunov),
+                        cfl=0.8,
+                        # Expected errors are exactly the same as with TreeMesh!
+                        l2=[2.515203865524688e-6],
+                        linf=[8.660338936650191e-6])
+    # Ensure that we do not have excessive memory allocations
+    # (e.g., from type instabilities)
+    @test_allocations(Trixi.rhs!, semi, sol, 1000)
+end
+
 @trixi_testset "elixir_advection_nonperiodic.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_advection_nonperiodic.jl"),
                         l2=[5.641921365468918e-5],