Instantiation mode "partial" to "callable". Return the _target_ component as-is when in _mode_="callable" and no kwargs are specified

[ibro45]

Description

A _target_ component with _mode_="partial" will still be wrapped in functools.partial even when no kwargs are passed: functool.partial(component). In such cases, the component can just be returned as-is.

If you agree with this, I will add tests for it. Thank you!

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[KumoLiu]

Hi @ibro45, thanks for your PR, could you please mention the case when it will be an issue? Perhaps a small snippets of code. Thanks.

[ibro45]

I was trying to achieve this:

    inferer:
        _target_: monai.inferers.PatchInferer
        batch_size: 8
        splitter:
            _target_: monai.inferers.SlidingWindowSplitter
            patch_size: [96, 96, 96]
            overlap: 0.5
        merger_cls:
            _target_: monai.inferers.AvgMerger  # I had a custom merger here that I would have to import if I wanted to use $ 
            _mode_: partial

but it would fail to instantiate because the PatchInferer complained that the merger_cls is not a subclass of Merger, but a functools.partial instead.

I know this could be solved with $, but it may require additional importing which _target_ does not need. It simply seems like a neater option to use _target_ there.

Thank you!

[KumoLiu]

but it would fail to instantiate because the PatchInferer complained that the merger_cls is not a subclass of Merger, but a functools.partial instead.

I get the point now, so instead of return the component directly when no kwargs, I would suggest add a mode here or make it clear in the docstring.

MONAI/monai/utils/module.py

Lines 235 to 239 in 6c9e49e

	__mode: the operating mode for invoking the (callable) ``component`` represented by ``__path``:
	- ``"default"``: returns ``component(**kwargs)``
	- ``"partial"``: returns ``functools.partial(component, **kwargs)``
	- ``"debug"``: returns ``pdb.runcall(component, **kwargs)``

What do you think?
cc @ericspod @Nic-Ma

[ericspod]

but it would fail to instantiate because the PatchInferer complained that the merger_cls is not a subclass of Merger, but a functools.partial instead.

I get the point now, so instead of return the component directly when no kwargs, I would suggest add a mode here or make it clear in the docstring.

I'd suggest a mode name change too. Perhaps "partial" should become "callable" or something to indicate that you could get a partial object back or just whatever the callable thing was if you gave no arguments.

[ibro45]

I think renaming "partial" to "callable" works with appropriate docstrings.

I may be overcomplicating it here, but what about changing the mode names as follows:

• "default" -> "invoke" mode - Executes a function or instantiates a class immediately, returning the output or instance.

• "partial" -> "callable" mode - Directly returns the function or class for future invoking. If kwargs are provided, it creates a functools.partial combining these kwargs with the function or class, enabling delayed invocation with pre-set parameters.

• "debug" stays as-is.

[ericspod]

I think renaming "partial" to "callable" works with appropriate docstrings.

I may be overcomplicating it here, but what about changing the mode names as follows:

* `"default"` -> `"invoke"` mode - Executes a function or instantiates a class immediately, returning the output or instance.

* `"partial"` -> `"callable"` mode -  Directly returns the function or class for future invoking. If kwargs are provided, it creates a `functools.partial` combining these kwargs with the function or class, enabling delayed invocation with pre-set parameters.

* `"debug"` stays as-is.

I would leave "default" alone but otherwise this sounds sensible. @KumoLiu thoughts?

[KumoLiu]

I would leave "default" alone but otherwise this sounds sensible. @KumoLiu thoughts?

Agreed.

[ericspod]

I would leave "default" alone but otherwise this sounds sensible. @KumoLiu thoughts?

Agreed.

Let's fix the minor flake issues but otherwise it looks good.

[KumoLiu]

Hi @ibro45, could you please fix the flake8 issue and DCO issue, then I will help merge this one. Thanks.
https://github.com/Project-MONAI/MONAI/actions/runs/7635293460/job/20800473351?pr=7413#step:7:387

[ibro45]

@KumoLiu should be good now, also renamed "partial" to "callable"

[KumoLiu]

/build