Philip Meier

I've [tested the protocol against `numpy`](https://github.com/pmeier/array-protocol/tree/numpy) and apart from the `device` attribute and the `array_namespace`, `dlpack`, and `dlpack_device` dunders, `numpy.ndarray`'s check fine.

> Can you indicate where this might be useful? [PEP485 stipulates](https://www.python.org/dev/peps/pep-0485/#handling-of-non-finite-numbers) "NaN is not considered close to any other value, including NaN." True, and I haven't encountered a use case...

> That does of course make it a little questionable to have `equal_nan` in `isclose`/`allclose` rather than only in testing functions like `assert_allclose` Good point. Since boolean operations and `isnan`...

> we must have a good introduction story to get from one definition to the other in a gradual fashion. And make sure especially NumPy would accept that; then other...

To investigate the impact of the proposed change, I've implemented it for `numpy` and run the `numpy`, `scipy`, and `scikit-learn` test suite against this patched version. - `numpy` Only a...

> Just wanna clarify: your patch used the math.isclose() relation, right? Yes, here are the details: I've used [`numpy-fb586a4`](https://github.com/numpy/numpy/tree/fb586a4f5760efaae57a9251ed98c4ebd3edcdf8) and applied this patch: ```git diff --git a/numpy/core/numeric.py b/numpy/core/numeric.py index 8bb37e291..a75eb1959...

There are more parts that are missing that are needed to crosslink the `pystiche_papers` documentation https://github.com/pystiche/pystiche/blob/71217c24557dfba05da5795547bf6f3034e7c66f/pystiche/core/_utils.py#L8-L12 https://github.com/pystiche/pystiche/blob/71217c24557dfba05da5795547bf6f3034e7c66f/pystiche/data/datasets.py#L11-L13

I'm not sure yet. If we are going with the name `PaperImageCollection` I think here would be the better place. If we go for something else, say `NSTImageCollection` `pystiche` might...

Awesome, go ahead!

After #557 there is now a clear path forward. We need to remove all warnings that include `pystiche.ops` from https://github.com/pystiche/pystiche/blob/6d0e45d33cd1c6e426e456a210b6ecbc0ada90ac/scripts/check_docs_references.py#L26-L40 and fix the documentation so that `tox -e tests-docs` no...