Feedback for Universal Wheel Package (`cupy-wheel`)

CuPy v10.4.0 (#6012) added an experimental meta package cupy-wheel on PyPI. Instead of specifying an individual wheel package name, users can now install CuPy with the single command line pip install cupy-wheel; the cupy-wheel meta-package probes the CUDA version installed in the users’ environment, and automatically picks and installs the real CuPy wheel package (e.g., cupy-cuda115).

It is currently marked experimental. Towards the v11 final release, we are going to stabilize this feature.

Major TODOs remaining are:

• Add documentation for downstream packages to use cupy-wheel
• Disable caching cupy-wheel package by pip to enforce running setup.py everytime
• Add long_description
• Automate the release process of the meta package

If you find difficulties using cupy-wheel, or have any comments or suggestions on cupy-wheel package, please feel free to post them here.

[leofang]

I see, thanks for reminder @kmaehashi. I had forgotten about it. I think the 2nd situation is less common, so I guess a warning like that should be sufficient.

[kmaehashi]

Thanks for testing, Leo!

1. CuPy from conda is already installed, and the user attempts to install cupy-wheel:

   • In this case, this check is legit and will raise an error as expected (the error message can be improved, though)

👍

1. cupy-wheel is already installed, and the user attempts to install cupy from Conda:

   • In this case, there is not yet a mechanism to avoid this silliness:

I think it’s not possible to prevent this, but import cupy should warn in this case.

https://github.com/cupy/cupy/blob/3fedbb957b79782089868540065ca24b088f29c6/cupy/_environment.py#L402

Perhaps cupy-wheel should also create a cupy empty package to keep the name occupied?

This will confuse pip (e.g., in this case pip install -U cupy will try to download cupy tarball from PyPI and build from source), so I think it’s better to avoid it.