Andrey Prokopenko

Ripped out ROCThrust version per @masterleinad's suggestion, will add it to #6793 once this PR is merged.

@masterleinad Could you please help me figure out the SYCL build failures? There is some issue with comparator being device copyable. Perhaps, it would need the same treatment as OpenMPTarget...

Just wanted to confirm: will we be able to write something like this downstream and will it work? Including linking to `rocthrust` as long as we link to `Kokkos::kokkos`. ```cmake...

Rebased on `develop` to allow integration of rocThrust's `sort_by_key` in this PR.

`sort_by_key` is the most pressing kernel. Other segmented kernels are available in Thrust also supports other segmented kernels (see [here](https://thrust.github.io/doc/namespacethrust.html)): `{exclusive,inclusive}_scan_by_key`, `merge_by_key`, `reduce_by_key`, `set_{difference,intersection,symmetric_difference,union}_by_key`, `stable_sort_by_key`. From ArborX perspective, we would...

> Given these observations, it looks like it makes sense to provide May also want to have a variant with iterators.

> What benefit would that have over going through `Views`? It's in addition to, not instead of. Following `std` algorithms, and make it possible to run within a kernel (of...

> One other thing that would be really useful for LAMMPS is the ability to sort by key, then sort duplicate values on another criteria, i.e. an outer and inner...

We have a similar problem in ArborX. So far, we are bypassing it by using two 32-bit ints and converting them to a 64-bit for sorting. Not sure how long...

> @stanmoore1 I was imagining something like I'm not sure about the performance of the custom operators. I think even for pod int types, using them is much slower than...