Implementing checkpointer for coupled model

[taimoorsohail]

This PR supersedes #381 adding a new run_coupled! function that replaces the run! function in Oceananigans. adds new methods so that checkpointing works for coupled ocean-sea ice simulations with PrescribedAtmosphere.

with @navidcy

[glwagner]

I don't agree with the design that creates a new function called run_coupled!. However, one could extend run! for a Simulation of OceanSeaIceModel. I'm not sure if there is a reason to keep both versions of run!.

[navidcy]

I don't agree with the design that creates a new function called run_coupled!. However, one could extend run! for a Simulation of OceanSeaIceModel. I'm not sure if there is a reason to keep both versions of run!.

Yes, we also agree. We don't like that either!
We were playing around with extending run! but couldn't figure out a way to differentiate the methods...

Somehow this:

function run!(simulation::Simulation{<:OceanSeaIceSimulation}`; pickup)
    if pickup
        ... do extra things to pick up a coupled model
    end

    run!(simulation) # Oceananigans.Simulations.run!
    return nothing
end

wasn't working for us yesterday.

Don't worry too much atm, it's mostly playing around. When we settle or if we get stuck we can ping you.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 39 lines in your changes missing coverage. Please review.

Project coverage is 0.00%. Comparing base (9efec12) to head (9f9ca89).

Files with missing lines	Patch %	Lines
src/OceanSeaIceModels/ocean_sea_ice_model.jl	0.00%	21 Missing ⚠️
src/OceanSeaIceModels/PrescribedAtmospheres.jl	0.00%	17 Missing ⚠️
src/ClimaOcean.jl	0.00%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #401   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files         40      40           
  Lines       2300    2329   +29     
=====================================
- Misses      2300    2329   +29     

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[taimoorsohail]

Linking issue #404 to this PR

[glwagner]

I don't agree with the design that creates a new function called run_coupled!. However, one could extend run! for a Simulation of OceanSeaIceModel. I'm not sure if there is a reason to keep both versions of run!.

Yes, we also agree. We don't like that either! We were playing around with extending run! but couldn't figure out a way to differentiate the methods...

Somehow this:

function run!(simulation::Simulation{<:OceanSeaIceSimulation}`; pickup)
    if pickup
        ... do extra things to pick up a coupled model
    end

    run!(simulation) # Oceananigans.Simulations.run!
    return nothing
end

wasn't working for us yesterday.

Don't worry too much atm, it's mostly playing around. When we settle or if we get stuck we can ping you.

To implement this, you need to first work on a PR in Oceananigans that exposes an interface for "picking up a simulation", which has a default implementation in Oceananigans, but which can be specialized for the type of Simulation. Then you can specialize for a simulation of OceanSeaIceModel here.

[navidcy]

After 9ab0df1 I can run the checkpointer_mwe.jl with Oceananigans 0.95.26 (not the branch from CliMA/Oceananigans.jl#4216)!

[navidcy]

@glwagner can you review? if you are happy we can convert the checkpointer_mwe.jl into a test and we are good to go I think

[navidcy]

Just note that I’m refactoring this. It’s almost there. But haven’t pushed yet.

[navidcy]

x-ref CliMA/Oceananigans.jl#4250

[navidcy]

I plan to work on this early next week