Add generic pow method for arrays

[multimeric]

Closes #1047.

Originally I was going to make separate powi() and powf() methods, but this isn't convenient because numtraits groups them together using one method.

One open question is how to get an integer array to take a float power and vice-versa, because numtraits doesn't seem to implement this use-case.

I've written two tests, which are in the documentation. I hope that's sufficient.

[multimeric]

@ maintainers, this seems to be failing because of something to do with #[inline], which I haven't touched. Is master broken or did this PR break it in a confusing way?

[jturner314]

@ maintainers, this seems to be failing because of something to do with #[inline], which I haven't touched. Is master broken or did this PR break it in a confusing way?

master currently fails CI due to new warnings with Rust nightly. I have a fix in #1054, which I'll merge as soon as CI passes.

[multimeric]

Great thanks. Hopefully this will rebuild automatically once that gets merged?

[jturner314]

Great thanks. Hopefully this will rebuild automatically once that gets merged?

Once #1054 is merged, I think you'll need to fetch the latest master from GitHub, rebase the pow branch onto it, and then force-push pow to update this PR. Are you familiar with how to do that, or would you like assistance?

[multimeric]

I think I can just pull master in my branch and then push my branch right?

[jturner314]

I think I can just pull master in my branch and then push my branch right?

That works too. The only disadvantage is that the commit history won't be as pretty as with a rebase.

[multimeric]

By the way, can I have some advice on the "error: unused import: Pow" I'm getting in the build? I am using that trait in my method, but I guess when we don't have the std feature enabled the method is skipped and so Pow seems to be unused?

[multimeric]

That works too. The only disadvantage is that the commit history won't be as pretty as with a rebase.

Okay I've rebased.

[jturner314]

By the way, can I have some advice on the "error: unused import: Pow" I'm getting in the build? I am using that trait in my method, but I guess when we don't have the std feature enabled the method is skipped and so Pow seems to be unused?

Yes, that's the issue. The simplest fix would be move use num_traits::Pow; to a separate line and add #[cfg(feature = "std")]. Edit: Actually, just move Pow onto the same line as the use num_traits::Float import. Edit2: Great, it looks like you noticed that.

[multimeric]

Yes, that's the issue. The simplest fix would be move use num_traits::Pow; to a separate line and add #[cfg(feature = "std")].

Done, thank you.

[multimeric]

Damn, it looks like this is all duplicating a subset of #1042. I wish I knew about that!

[multimeric]

Closing in favour of #1042.