Support for kernels on subsets of variables

[simonbyrne]

Description

Allows use of MPIStateArrays with different state variables then defined in the kernel. Should make it easier to operate on subsets of state.

• Code follows the style guidelines OR N/A.
• Unit tests are included OR N/A.
• Code is exercised in an integration test OR N/A.
• Documentation has been added/updated OR N/A.

[simonbyrne]

bors try

[bors]

try

Build failed:

• test-os (ubuntu-latest)

[charleskawczynski]

Suggested change

	struct Prognostic <: AbstractStateType end
	struct PrognosticIn <: AbstractStateType end
	struct PrognosticOut <: AbstractStateType end
	abstract type AbstractStreamType end
	struct In <: AbstractStreamType end
	struct Out <: AbstractStreamType end
	struct InOut <: AbstractStreamType end
	struct Prognostic{T<: AbstractStreamType} <: AbstractStateType end
	Prognostic() = Prognostic{InOut}()

Would something like this be simpler if we plan to extend this to other AbstractStateType's?

[simonbyrne]

Possibly. There is the chance we might want them to be specific to each kernel as well.

[simonbyrne]

bors try

[bors]

try

Build failed:

• test-os (ubuntu-latest)

[simonbyrne]

bors try

[bors]

try

Build failed:

• format

[simonbyrne]

bors try

[bors]

try

Build failed:

• buildkite/climatemachine-docs