Update to ndarray 0.14 about linfa

[bytesnake]

thanks for tackling this, last time I looked ndarray-stats still used the old ndarray version

[bytesnake]

but it isn't anymore, version 0.4.0 is already published on crates.io!

[relf]

ah yes! 🤦 what did I check?

[quietlychris]

@relf As of two days ago (March 25) it actually looks like ndarray has bumped its version up from 0.14 to 0.15. I'm not sure how many breaking chances are actually between the two, but I think if you're planning on updating the version up from 0.13 anyway, it might make sense to jump all the way up (assuming that there's no major issues in the 0.15.0).

[relf]

Yep, I haven't dived in but it seems there are more changes from 0.14 to 0.15 than from 0.13 to 0.14.

That said, I think linfa should have at least a minor release for each minor release of ndarray (here we could have linfa 0.4 with ndarray 0.14) because upgrading ndarray is not that easy due to the dependencies.

I do not know how cargo handles several versions of the same crate but I experienced compilation problems when there are various versions of ndarray pulled by various dependencies. And finally I waited for that all dependencies upgraded to ndarray 0.14 before making this PR.

Unfortunately, the sprs issue is blocking right now, and I do not know what is the best course of actions. I picked the revision sparsemat/sprs@761d4f0 where sprs upgraded to ndarray 0.14 to make this PR compile. Should we wait for the issue resolution (which would be the same with ndarray 0.15 anyway) or could we publish a linfa 0.4 based on this?

[relf]

fixed by #110