Documentation for Allocator and BackendLike

[havogt]

No description provided.

[msimberg]

Thanks @havogt!

The model_backends.py module docstring almost perfectly answers my questions.

I don't know if this needs explicit mentioning somewhere, but handling of None is not described. I see now that BackendLike is ... | None. In

Backends can either be concrete GT4Py backends or 'BackendLike's, which are either concrete backends
or descriptions of how to construct a concrete backend

I assume None belongs to description of how to construct a concrete backend, in the form of "use the default"?

Additionally, we use Backend | None in some places. This is a subset of BackendLike, so should we just be using BackendLike in place of Backend | None? Can one pass None as allocator or does one have to get a concrete allocator with get_allocator(None) first?

[havogt]

I assume None belongs to description of how to construct a concrete backend, in the form of "use the default"?

Unfortunately, no. None is kind of a concrete backend: it's indicating to use embedded. The reason behind is: backends can be seen as a series of transformations on the original python function. If you say None it means don't do any transformation and just execute as is. In hindsight, this was a mistake as it creates confusion in user-code... We'll probably change that in the future. I'll add a comment.

[havogt]

cscs-ci run default

[havogt]

cscs-ci run distributed

[github-actions]

Mandatory Tests

Please make sure you run these tests via comment before you merge!

• cscs-ci run default
• cscs-ci run distributed

Optional Tests

To run benchmarks you can use:

• cscs-ci run benchmark-bencher

To run tests and benchmarks with the DaCe backend you can use:

• cscs-ci run dace

To run test levels ignored by the default test suite (mostly simple datatest for static fields computations) you can use:

• cscs-ci run extra

For more detailed information please look at CI in the EXCLAIM universe.