[Numpy-discussion] NEP-18 comment

[Frederic Bastien]

Hi,

I was told recently about the NEP-18. I like it, but I have a comment.

At first, it is enabled in a release by setting an environment variable.
Then in the following release, it is enabled by default.

Is it possible to allow for the second release to disable it by an environment variable? This would allow to disable it for people that would be inconvenienced by this change.

Who could be negatively impacted by this? Small array operation.

I recall many years ago of much effort to speed up small array, including at least one GSoC. I didn't do timing, but I'm pretty sure the change needed for NEP-19 raise the default overhead for all operation that it impact.
I also recall people in the mailing list asking how to speed up the small array case.
So giving people a way to not pay for that overhead would make sure that for people that care about the small array cases won't pay that extra overhead price. So they won't see a slowdown by updating NumPy.

Probably less than 1% of user will enable the new functionality in the current release as it is not enabled by default. Making it easy to try is great, but doesn't guaranty that it will be tested in all corner cases. So it isn't sure we would heard before the second release about regression this change does.

What do you think about that small changes?

Thanks for the great work on such important library.

Frédéric Bastien

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