`array_api_compat.numpy.asarray(torch.Tensor)` returns a `torch.Tensor`

[izaid]

This feels like a bug to me. My expectation is that xp.asarray converts to an array object in the xp namespace if that operation is supported.

>>> import torch
>>> import array_api_compat.numpy
>>> x = torch.arange(10)
>>> array_api_compat.numpy.asarray(x)
tensor([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

[rgommers]

Agreed, that is a bug. This line looks wrong:

array-api-compat/array_api_compat/common/_aliases.py

Line 352 in d10bf57

return obj

[ivirshup]

FWIW, this bug seems to have been introduced in 1.5, and had the correct behaviour in 1.4.

Also is not limited to this case, for instance I ran into this for array_api_compat.cupy.asarray(np.ndarray)

[ivirshup]

What is the expected behavior for xp.asarray(some_other_array_type)? Are there cases it should fail in?

[asmeurer]

If the input type is one of the types mentioned in the standard (in the type signature), it should convert that input type. Otherwise, generally for array-api-compat, any behavior outside of the standard should just pass through to the library function. So in this case, asarray() should indeed convert the input because normal np.asarray(Tensor) works (and also I think Tensor falls under the category of SupportsBufferProtocol).

[asmeurer]

Bisected it to this commit, which made that line apply to objects with __array__, instead of just objects that are already ndarray subclasses. 8ee1613 CC @lithomas1

[lithomas1]

Yeah, I messed up asarray. Sorry about that. I have a WIP branch fixing that ,and some other dask stuff.

[asmeurer]

OK, I'll hold off on looking at this for now so I don't step on your toes. You may want to integrate the test from https://github.com/data-apis/array-api-compat/pull/109/files. It may also be necessary to update the copy logic generally similar to data-apis/array-api-strict#15. I don't know if the "check if a copy was made" trick can work for cupy and dask, but if it can we should use it. If there end up being too many library-specific checks in the asarray code it may be more prudent to just split it into separate helpers for each library.

[lithomas1]

@izaid @ivirshup

Are you able to test main again? I should have this bug fixed, but just wanted to make sure.

[izaid]

@izaid @ivirshup

Are you able to test main again? I should have this bug fixed, but just wanted to make sure.

Is there a link somewhere with steps to follow? I only have array_api_compat installed from pip.

[lucascolley]

• clone array_api_compat main
• cd array_api_compat
• create a new env
• pip install torch
• python
• then run your example above

should work?

[ivirshup]

Looks like 94e42df works for cupy for me. Thanks!

Unfortunately, did have to nuke my cuda install, but I'm pretty confident that's unrelated.