I've got the results for the benchmark! 👍

Script: numpytest.py

import pyperf

runner = pyperf.Runner()

setup="""
import numpy as np
from numpy.polynomial import Polynomial

x = np.array([2, 3, 4])
y = np.array([2, 3])

p = Polynomial([1, 2, 3.])
"""   
runner.timeit(name=f"atleast_2d(1)", stmt=f"np.atleast_2d(1)", setup=setup)
runner.timeit(name=f"atleast_2d(x)", stmt=f"np.atleast_2d(x)", setup=setup)
runner.timeit(name=f"atleast_2d(1, x )", stmt=f"np.atleast_2d(1, x )", setup=setup)

runner.timeit(name=f"atleast_3d(1)", stmt=f"np.atleast_3d(1)", setup=setup)
runner.timeit(name=f"atleast_3d(x)", stmt=f"np.atleast_3d(x)", setup=setup)
runner.timeit(name=f"atleast_3d(1, x )", stmt=f"np.atleast_3d(1, x )", setup=setup)

runner.timeit(name=f"polyadd", stmt=f"np.polyadd(x, y)", setup=setup)

(Credits to @eendebakpt for the great script👍)

Results:

Old (numpy original):

atleast_2d(1): Mean +- std dev: 728 ns +- 21 ns
atleast_2d(x): Mean +- std dev: 575 ns +- 25 ns
atleast_2d(1, x ): Mean +- std dev: 1.16 us +- 0.07 us

atleast_3d(1): Mean +- std dev: 761 ns +- 42 ns
atleast_3d(x): Mean +- std dev: 635 ns +- 63 ns
atleast_3d(1, x ): Mean +- std dev: 1.17 us +- 0.04 us

polyadd: Mean +- std dev: 2.88 us +- 0.13 us

New (numpy by Benedikt Johannes):

atleast_2d(1): Mean +- std dev: 662 ns +- 43 ns
atleast_2d(x): Mean +- std dev: 488 ns +- 22 ns
atleast_2d(1, x ): Mean +- std dev: 1.12 us +- 0.05 us

atleast_3d(1): Mean +- std dev: 671 ns +- 22 ns
atleast_3d(x): Mean +- std dev: 512 ns +- 24 ns
atleast_3d(1, x ): Mean +- std dev: 1.15 us +- 0.06 us

polyadd: Mean +- std dev: 2.80 us +- 0.08 us

Test failure is unrealted (can't install build environment)

Should I write release notes 2.5 for this change, @ngoldbaum? Or is this done by the team? I only know this from CPython.

Because it says:

Beyond changes to a functions docstring and possible description in the general documentation, if your change introduces any user-facing modifications they may need to be mentioned in the release notes. To add your change to the release notes, you need to create a short file with a summary and place it in doc/release/upcoming_changes. The file doc/release/upcoming_changes/README.rst details the format and filename conventions.

And the change is kind of user facing in my opinion because the performance is changed and users might notice this (and the latest news document also includes performance improvements).

minor performance improvements like this don't need a release note

All checks pass, do I need to use any command like /merge?

So without the unrelated one

Please be patient, I added the milestone so this won't get lost before the next major release this summer.

Thank you!

But one question: Is everything finished that I got to do? So can I just wait for the summer without doing anything for this?

Maybe sooner, this PR has only been open for a day or so. The project doesn't move terribly quickly and people do code review as their time and interest permits.

I was also planning to look closer at this at some point. Usually we like to leave PRs that make performance improvements and add new features open for at least a few days.

Also, IMO this PR shouldn't be backported, so in practice very few people will be able to use this until NumPy 2.5 comes out this summer.

Ah, okay, thank you very much for the Information! Don’t feel stressed about it!