Add missing Rotation functions

[chrisflesher]

Added some missing functions so the API matches scipy now:

align_vectors
create_group
random
reduce

Also fixed a bug in from_euler when only one axis is specified.

This PR is the continuation PR #17192 but based on the latest main branch.

[chrisflesher]

Hi @jonesk7734 could you trigger CI for this please? Hopefully it is ready now...

[chrisflesher]

Hi @jakevdp could you trigger CI for this please? Hopefully it is ready now...

[chrisflesher]

I wasn't able to get this PR accepted so have been making updates in a separate repo:

https://github.com/chrisflesher/jax-scipy-spatial

I've written it to be easy to merge back into the JAX repo if there's desire to do so in the future.

[jakevdp]

Hi - sorry we lost track of this. The rotation functions are now considered out-of-scope for jax.scipy, so we likely will not be adding additional functionality to them.

A separate package looks useful, but a better approach may be to support jax rotation operations via scipy's array API support (see scipy/scipy#20544). JAX is close to having full support for the Array API (see #21088), and once scipy.spatial adds array API support those functions will be able to be used directly on JAX arrays, and lower to JAX operations. At that point, we will likely deprecate and remove jax.scipy.spatial.

[chrisflesher]

Ah, sounds great! Thanks for letting me know about the Array API changes, was planning to manually convert more scipy libraries but this will free up some time to work on something else.

[mdhaber]

I think the best existing issue for adding array API support to scipy.spatial is scipy/scipy#18867. It might be worth creating a more specific issue for spatial similar to scipy/scipy#20544 (which is specific to stats).