Adapting Float64 struct equations to Float32 GPU code

This conversion has a bug when the equation struct present some parameters that are entered by the user. For example `CompressibleEulerEquations2D(gamma)`. If `gamma` is not of the same type as `real_type` for the GPU kernel, the code will not run and will return the following error: ```julia ERROR: LoadError: BoundsError: attempt to access NTuple{4, String} at index [5] Stacktrace: [1] getindex(t::Tuple, i::Int64) @ Base ./tuple.jl:31 [2] (::Trixi.var"#1796#1803"{…})(file::HDF5.File) @ Trixi ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution_dg.jl:67 [3] (::HDF5.var"#17#18"{HDF5.HDF5Context, @Kwargs{}, Trixi.var"#1796#1803"{…}, HDF5.File})() @ HDF5 ~/.julia/packages/HDF5/8g5ny/src/file.jl:101 [4] task_local_storage(body::HDF5.var"#17#18"{…}, key::Symbol, val::HDF5.HDF5Context) @ Base ./task.jl:304 [5] #h5open#16 @ ~/.julia/packages/HDF5/8g5ny/src/file.jl:96 [inlined] [6] h5open @ ~/.julia/packages/HDF5/8g5ny/src/file.jl:94 [inlined] [7] save_solution_file(u::Array{…}, time::Float64, dt::Float64, timestep::Int64, mesh::P4estMesh{…}, equations::CompressibleEulerEquations2D{…}, dg::DGSEM{…}, cache::@NamedTuple{…}, solution_callback::SaveSolutionCallback{…}, element_variables::Dict{…}, node_variables::Dict{…}; system::String) @ Trixi ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution_dg.jl:47 [8] save_solution_file @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution_dg.jl:8 [inlined] [9] #save_solution_file#1791 @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:306 [inlined] [10] save_solution_file @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:294 [inlined] [11] macro expansion @ ~/.julia/packages/TrixiBase/MGeKl/src/trixi_timeit.jl:67 [inlined] [12] #save_solution_file#1788 @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:285 [inlined] [13] save_solution_file @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:260 [inlined] [14] macro expansion @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:252 [inlined] [15] macro expansion @ ~/.julia/packages/TrixiBase/MGeKl/src/trixi_timeit.jl:67 [inlined] [16] (::SaveSolutionCallback{…})(integrator::OrdinaryDiffEqCore.ODEIntegrator{…}) @ Trixi ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:247 [17] initialize_save_cb!(solution_callback::SaveSolutionCallback{…}, u::ROCArray{…}, t::Float64, integrator::OrdinaryDiffEqCore.ODEIntegrator{…}) @ Trixi ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:181 [18] initialize_save_cb! @ ~/workspace/dev/Trixi.jl/src/callbacks_step/save_solution.jl:171 [inlined] [19] initialize!(u::ROCArray{…}, t::Float64, integrator::OrdinaryDiffEqCore.ODEIntegrator{…}, any_modified::Bool, c::DiscreteCallback{…}, cs::DiscreteCallback{…}) @ DiffEqBase ~/.julia/packages/DiffEqBase/CJTzr/src/callbacks.jl:17 [20] initialize!(::ROCArray{…}, ::Float64, ::OrdinaryDiffEqCore.ODEIntegrator{…}, ::Bool, ::DiscreteCallback{…}, ::DiscreteCallback{…}, ::Vararg{…}) @ DiffEqBase ~/.julia/packages/DiffEqBase/CJTzr/src/callbacks.jl:18 [21] initialize!(::ROCArray{…}, ::Float64, ::OrdinaryDiffEqCore.ODEIntegrator{…}, ::Bool, ::DiscreteCallback{…}, ::DiscreteCallback{…}, ::Vararg{…}) @ DiffEqBase ~/.julia/packages/DiffEqBase/CJTzr/src/callbacks.jl:18 [22] initialize!(::ROCArray{…}, ::Float64, ::OrdinaryDiffEqCore.ODEIntegrator{…}, ::Bool, ::DiscreteCallback{…}, ::DiscreteCallback{…}, ::Vararg{…}) @ DiffEqBase ~/.julia/packages/DiffEqBase/CJTzr/src/callbacks.jl:18 [23] initialize! @ ~/.julia/packages/DiffEqBase/CJTzr/src/callbacks.jl:7 [inlined] [24] initialize_callbacks!(integrator::OrdinaryDiffEqCore.ODEIntegrator{…}, initialize_save::Bool) @ OrdinaryDiffEqCore ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:1089 [25] _ode_init(prob::ODEProblem{…}, alg::CarpenterKennedy2N54{…}, timeseries_init::Tuple{}, ts_init::Tuple{}, ks_init::Tuple{}; saveat::Tuple{}, tstops::Tuple{}, d_discontinuities::Tuple{}, save_idxs::Nothing, save_everystep::Bool, save_on::Bool, save_discretes::Bool, save_start::Bool, save_end::Nothing, callback::CallbackSet{…}, dense::Bool, calck::Bool, dt::Float64, dtmin::Float64, dtmax::Float64, force_dtmin::Bool, adaptive::Bool, abstol::Nothing, reltol::Nothing, gamma::Nothing, qmin::Nothing, qmax::Nothing, qsteady_min::Nothing, qsteady_max::Nothing, beta1::Nothing, beta2::Nothing, qoldinit::Nothing, fullnormalize::Bool, failfactor::Int64, maxiters::Int64, internalnorm::typeof(DiffEqBase.ODE_DEFAULT_NORM), internalopnorm::typeof(LinearAlgebra.opnorm), isoutofdomain::typeof(DiffEqBase.ODE_DEFAULT_ISOUTOFDOMAIN), unstable_check::typeof(DiffEqBase.ODE_DEFAULT_UNSTABLE_CHECK), verbose::Bool, controller::Nothing, timeseries_errors::Bool, dense_errors::Bool, advance_to_tstop::Bool, stop_at_next_tstop::Bool, initialize_save::Bool, progress::Bool, progress_steps::Int64, progress_name::String, progress_message::typeof(DiffEqBase.ODE_DEFAULT_PROG_MESSAGE), progress_id::Symbol, userdata::Nothing, allow_extrapolation::Bool, initialize_integrator::Bool, alias::ODEAliasSpecifier, initializealg::DiffEqBase.DefaultInit, rng::Nothing, save_noise::Bool, delta::Nothing, W::Nothing, P::Nothing, sqdt::Nothing, noise::Nothing, c::Nothing, rate_constants::Nothing, _cache::Nothing, _u::Nothing, _uprev::Nothing, seed::UInt64, kwargs::@Kwargs{}) @ OrdinaryDiffEqCore ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:812 [26] _ode_init @ ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:47 [inlined] [27] #__init#71 @ ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:37 [inlined] [28] __init (repeats 2 times) @ ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:19 [inlined] [29] __solve(::ODEProblem{…}, ::CarpenterKennedy2N54{…}; kwargs::@Kwargs{…}) @ OrdinaryDiffEqCore ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:9 [30] __solve @ ~/.julia/packages/OrdinaryDiffEqCore/rnOL4/src/solve.jl:1 [inlined] [31] solve_call(_prob::ODEProblem{…}, args::CarpenterKennedy2N54{…}; merge_callbacks::Bool, kwargshandle::Nothing, kwargs::@Kwargs{…}) @ DiffEqBase ~/.julia/packages/DiffEqBase/CJTzr/src/solve.jl:172 [32] solve_call @ ~/.julia/packages/DiffEqBase/CJTzr/src/solve.jl:137 [inlined] [33] #solve_up#38 @ ~/.julia/packages/DiffEqBase/CJTzr/src/solve.jl:646 [inlined] [34] solve_up @ ~/.julia/packages/DiffEqBase/CJTzr/src/solve.jl:619 [inlined] [35] #solve#37 @ ~/.julia/packages/DiffEqBase/CJTzr/src/solve.jl:603 [inlined] [36] top-level scope @ ~/workspace/dev/Trixi.jl/examples/p4est_2d_dgsem/elixir_euler_source_terms_gpu.jl:60 [37] include(fname::String) @ Base.MainInclude ./client.jl:494 [38] top-level scope @ REPL[20]:1 in expression starting at /home/marco/workspace/dev/Trixi.jl/examples/p4est_2d_dgsem/elixir_euler_source_terms_gpu.jl:60 Some type information was truncated. Use `show(err)` to see complete types. ``` Apparently we do not retrieve the correct number of variables from: (Trixi.jl/src/callbacks_step/save_solution_dg.jl) ```julia # Reinterpret the solution array as an array of conservative variables, # compute the solution variables via broadcasting, and reinterpret the # result as a plain array of floating point numbers data = Array(reinterpret(eltype(u), solution_variables.(reinterpret(SVector{nvariables(equations), eltype(u)}, u), Ref(equations)))) # Find out variable count by looking at output from `solution_variables` function n_vars = size(data, 1) ``` When forcing the code to use the correct number of variables this problem is fixed.