On Thu, Apr 25, 2019 at 12:46 PM Marten van Kerkwijk < m.h.vankerkw...@gmail.com> wrote:
> It seems we are adding to the wishlist! I see four so far: > 1. Exposed in API, can be overridden with __array_ufunc__ > 2. One that converts everything to ndarray (or subclass); essentially the > current implementation; > 3. One that does asduckarray > 4. One that assumes all arguments are arrays. > > Maybe handiest would be if there is a method to coerce all relevant > arguments with a function of one's choice? I.e., in the example of Stephan, > one would have > ``` > if function in JUST_COERCE: > coerced_args, coerced_kwargs = function.__coerce__(np.asanyarray, > *args, **kwargs) > return function.__implementation__(*coerced_args, **coerced_kwargs) > ``` > Actually, this might in fact work with the plan proposed here, if we allow > for an extra, optional kwarg that contains the coercion function, that is > ``` > return function.__implementation__(*args, > coercion_function=np.asanyarray, **kwargs) > ``` > > The possible advantage of this over yet more dunder methods is that one > can fine-tune the extent to which something has to mimic an array properly > (e.g., run `asanyarray` only if `shape` is not present). > I do like the look of this, but keep in mind that there is a downside to exposing the implementation of NumPy functions -- now the implementation details become part of NumPy's API. I suspect we do not want to commit ourselves to never changing the implementation of NumPy functions, so at the least this will need careful disclaimers about non-guarantees of backwards compatibility. But for now, I would love to pick a name for "essentially the current implementation", which is something that would make a big difference for near-term NEP-18 use cases. Some options: __skipping_array_function__ __coercive_implementation__ __asarray_implementaiton__ The last two are not quite right, since there is some legacy dispatching to methods. Maybe __skipping_array_function__ is the best? Whatever we pick, we can always make it an alias later, e.g., for func.__implementation__(*args, coercion_function=np.asanyarray, **kwargs). > It would be nice, though, if we could end up with also option 4 being > available, if only because code that just can assume ndarray will be > easiest to read. > This could perhaps just be coercion_function=None? Or maybe we want to keep around coercion_function=None for "do whatever ad-hoc coercion NumPy current does"? > > All the best, > > Marten > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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