Update vector_of_array.jl

[lxvm]

Fix #354

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[lxvm]

Oops this might violate the copying semantics of getindex

[AayushSabharwal]

Copying isn't really an issue here, since we can't avoid it. However, I'd recommend using the Adapt.adapt(...) wrapper instead of Array. That way the output type matches the type of the contained arrays.

[lxvm]

I meant to say that getindex must copy, but Array may not. Is Adapt.adapt required to copy?

[AayushSabharwal]

I think it copies, and anyway Array(::VectorOfArray) will copy anyway?

[lxvm]

The following method of Array doesn't copy:

RecursiveArrayTools.jl/src/vector_of_array.jl

Line 89 in 351cb40

VA.u

I'll probably keep the original method and add one with numeric elements that forwards the indices to the inner array.

[lxvm]

I updated my pr to just add a new method which will fix the broken case. I also rebased onto the main branch. I hope this looks good.