VolumeIntegrals: Default fluxes, keyword constructors (#2617)

* `VolumeIntegrals`: Default fluxes, keyword constructors

* fix

* surfInts, kw O2

* bf

* rev

* rev

* fix

Author: DanielDoehring

examples/structured_1d_dgsem/elixir_euler_source_terms_nonperiodic_fvO2.jl

@@ -20,7 +20,8 @@ boundary_conditions = (x_neg = boundary_condition,
 polydeg = 8 # Governs in this case only the number of subcells
 basis = LobattoLegendreBasis(polydeg)
 surface_flux = flux_hll
-volume_integral = VolumeIntegralPureLGLFiniteVolumeO2(basis, surface_flux,
+volume_integral = VolumeIntegralPureLGLFiniteVolumeO2(basis,
+                                                      volume_flux_fv = surface_flux,
                                                       reconstruction_mode = reconstruction_O2_inner,
                                                       slope_limiter = vanLeer)
 solver = DGSEM(polydeg = polydeg, surface_flux = surface_flux,

examples/structured_2d_dgsem/elixir_euler_ec.jl

@@ -11,9 +11,9 @@ initial_condition = initial_condition_weak_blast_wave
 ###############################################################################
 # Get the DG approximation space
 
-volume_flux = flux_ranocha
+volume_integral = VolumeIntegralFluxDifferencing(volume_flux = flux_ranocha)
 solver = DGSEM(polydeg = 4, surface_flux = flux_ranocha,
-               volume_integral = VolumeIntegralFluxDifferencing(volume_flux))
+               volume_integral = volume_integral)
 
 ###############################################################################
 # Get the curved quad mesh from a mapping function

examples/tree_1d_dgsem/elixir_euler_convergence_pure_fv.jl

@@ -8,8 +8,9 @@ equations = CompressibleEulerEquations1D(1.4)
 
 initial_condition = initial_condition_convergence_test
 
+volume_integral = VolumeIntegralPureLGLFiniteVolume(volume_flux_fv = flux_hllc)
 solver = DGSEM(polydeg = 3, surface_flux = flux_hllc,
-               volume_integral = VolumeIntegralPureLGLFiniteVolume(flux_hllc))
+               volume_integral = volume_integral)
 
 coordinates_min = 0.0
 coordinates_max = 2.0

examples/tree_1d_dgsem/elixir_euler_convergence_pure_fvO2.jl

@@ -12,7 +12,8 @@ initial_condition = initial_condition_convergence_test
 polydeg = 3 # Governs in this case only the number of subcells
 basis = LobattoLegendreBasis(polydeg)
 surface_flux = flux_hllc
-volume_integral = VolumeIntegralPureLGLFiniteVolumeO2(basis, surface_flux,
+volume_integral = VolumeIntegralPureLGLFiniteVolumeO2(basis,
+                                                      volume_flux_fv = surface_flux,
                                                       reconstruction_mode = reconstruction_O2_full,
                                                       slope_limiter = monotonized_central)
 solver = DGSEM(polydeg = polydeg, surface_flux = surface_flux,

src/solvers/dg.jl

@@ -90,6 +90,7 @@ create_cache(mesh, equations, ::VolumeIntegralWeakForm, dg, uEltype) = NamedTupl
 
 """
     VolumeIntegralFluxDifferencing(volume_flux)
+    VolumeIntegralFluxDifferencing(; volume_flux = flux_central)
 
 Volume integral type for DG methods based on SBP operators and flux differencing
 using a symmetric two-point `volume_flux`. This `volume_flux` needs to satisfy
@@ -117,6 +118,10 @@ struct VolumeIntegralFluxDifferencing{VolumeFlux} <: AbstractVolumeIntegral
     volume_flux::VolumeFlux
 end
 
+function VolumeIntegralFluxDifferencing(; volume_flux = flux_central)
+    return VolumeIntegralFluxDifferencing{typeof(volume_flux)}(volume_flux)
+end
+
 function Base.show(io::IO, ::MIME"text/plain", integral::VolumeIntegralFluxDifferencing)
     @nospecialize integral # reduce precompilation time
 
@@ -192,6 +197,7 @@ abstract type AbstractVolumeIntegralPureLGLFiniteVolume <: AbstractVolumeIntegra
 
 """
     VolumeIntegralPureLGLFiniteVolume(volume_flux_fv)
+    VolumeIntegralPureLGLFiniteVolume(; volume_flux_fv = flux_lax_friedrichs)
 
 A volume integral that only uses the subcell finite volume schemes of the
 [`VolumeIntegralShockCapturingHG`](@ref).
@@ -214,6 +220,10 @@ struct VolumeIntegralPureLGLFiniteVolume{VolumeFluxFV} <:
 end
 # TODO: Figure out if this can also be used for Gauss nodes, not just LGL, and adjust the name accordingly
 
+function VolumeIntegralPureLGLFiniteVolume(; volume_flux_fv = flux_lax_friedrichs)
+    return VolumeIntegralPureLGLFiniteVolume{typeof(volume_flux_fv)}(volume_flux_fv)
+end
+
 function Base.show(io::IO, ::MIME"text/plain",
                    integral::VolumeIntegralPureLGLFiniteVolume)
     @nospecialize integral # reduce precompilation time
@@ -229,7 +239,8 @@ function Base.show(io::IO, ::MIME"text/plain",
 end
 
 """
-    VolumeIntegralPureLGLFiniteVolumeO2(basis::Basis, volume_flux_fv;
+    VolumeIntegralPureLGLFiniteVolumeO2(basis::Basis;
+                                        volume_flux_fv = flux_lax_friedrichs,
                                         reconstruction_mode = reconstruction_O2_full,
                                         slope_limiter = minmod)
 
@@ -275,7 +286,8 @@ struct VolumeIntegralPureLGLFiniteVolumeO2{RealT <: Real, Basis, VolumeFluxFV,
     slope_limiter::Limiter # which type of slope limiter function
 end
 
-function VolumeIntegralPureLGLFiniteVolumeO2(basis::Basis, volume_flux_fv;
+function VolumeIntegralPureLGLFiniteVolumeO2(basis::Basis;
+                                             volume_flux_fv = flux_lax_friedrichs,
                                              reconstruction_mode = reconstruction_O2_full,
                                              slope_limiter = minmod) where {Basis}
     # Suffices to store only the intermediate boundaries of the sub-cell elements                                             
@@ -309,7 +321,8 @@ end
 
 """
     VolumeIntegralSubcellLimiting(limiter;
-                                  volume_flux_dg, volume_flux_fv)
+                                  volume_flux_dg = flux_central,
+                                  volume_flux_fv = flux_lax_friedrichs)
 
 A subcell limiting volume integral type for DG methods based on subcell blending approaches
 with a low-order FV method. Used with limiter [`SubcellLimiterIDP`](@ref).
@@ -327,8 +340,9 @@ struct VolumeIntegralSubcellLimiting{VolumeFluxDG, VolumeFluxFV, Limiter} <:
     limiter::Limiter
 end
 
-function VolumeIntegralSubcellLimiting(limiter; volume_flux_dg,
-                                       volume_flux_fv)
+function VolumeIntegralSubcellLimiting(limiter;
+                                       volume_flux_dg = flux_central,
+                                       volume_flux_fv = flux_lax_friedrichs)
     VolumeIntegralSubcellLimiting{typeof(volume_flux_dg), typeof(volume_flux_fv),
                                   typeof(limiter)}(volume_flux_dg, volume_flux_fv,
                                                    limiter)

test/test_tree_1d_euler.jl

@@ -58,7 +58,7 @@ end
 @trixi_testset "elixir_euler_convergence_pure_fv.jl (O2, constant reconstruction)" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_euler_convergence_pure_fv.jl"),
                         volume_integral=VolumeIntegralPureLGLFiniteVolumeO2(LobattoLegendreBasis(3),
-                                                                            flux_hllc,
+                                                                            volume_flux_fv = flux_hllc,
                                                                             reconstruction_mode = reconstruction_constant,
                                                                             slope_limiter = central_slope),
                         l2=[