AA/adaptive-dt

[egyaa20]

Add optional adaptive time-stepping via a new (optional) AdaptiveTimeStepping configuration block inside Runtime, ensuring compatability with other solvers and test cases. Time-step updates are handled through multiple dispatch update_dt! function to avoid if statements when adaptative stepping is turned on/off.

[mberto79]

@egyaa20 just added a few minor comments, the main change is to make modification to ensure this PR is GPU compatible. To allow this, I have left comment through the code, in addition, we need a new constructor for the Configuration type (in the file simulate_0_types.jl. Where we define the struct as:

@kwdef struct Configuration{SC,SL,RT,HW,BC,PP}
    schemes::SC
    solvers::SL
    runtime::RT
    hardware::HW
    boundaries::BC
    postprocess::PP = nothing
end
Adapt.@adapt_structure Configuration

We need to remove the default keyword constructor that's created with the @kwdef macro i.e.:

struct Configuration{SC,SL,RT,HW,BC,PP}
    schemes::SC
    solvers::SL
    runtime::RT
    hardware::HW
    boundaries::BC
    postprocess::PP
end
Adapt.@adapt_structure Configuration

Within a new custom constructor definition we will need to move the runtime object to the GPU so it can be accessed within kernels, it would look something like:

Configuration(; schemes, solvers, runtime, hardware, boundaries, postprocess=nothing) = begin
Configuration(
    schemes=schemes, 
    solvers=solvers, 
    hardware=hardware, 
    boundaries=boundaries, 
    postprocess=postprocess, 
    runtime=adapt(hardware.backend, runtime)
)
end

That should do it (although please check I didn't run the pseudo code above 🫤 )

Once we confirm GPU compitibility, I think this is ready to merge! Thanks!