[Feature] cross product

[petertsoi]

It would be nice to have a mx.cross/mx.linalg.cross that works like np.cross/np.linalg.cross.

[awni]

I think we don't need a primitive for this since it's just a handful of ops. If it's too slow the naive way we can re-evaluate.

I would do it with a split -> adds + multiplies -> concat.

[Saanidhyavats]

@awni PR related to this issue was updated 2 weeks back. Is it still under process or can I start working on it?

[awni]

I would pick a different open issue. That PR needs to be reviewed and I think it is almost done.