Gradients in ManifoldDiff?

[kellertuer]

When writing the first example in ManoptExamples.jl,
I noticed that grad_distance was still defined in Manopt.jl. I want to move those gradients out - for sure.
Sure, gradient conversion (in Manifold.jl) should stay there since those functions are very manifold-specific.

But besides in the examples, they could also be placed here? We could also collect other simple gradients, though I do not have many in mind for now.

[mateuszbaran]

I didn't really need grad_distance for anything so I didn't move it. It is very simple so I'm not even sure how useful it is but if you want put it in ManifoldDiff then it's also fine 🙂 .

[kellertuer]

We could also keep it in the ManopExample package, I am open to both.

[mateuszbaran]

Feel free to put it in the package you prefer 🙂

[kellertuer]

I think it would also fit here well, I will move it then the next days.