[Feature Request] Pair style hybrid/scaled with kokkos acceleration

[Leimeroth]

Bug report

Currently using -sf kk throws an error: Must use pair_style hybrid/scaled/kk with Kokkos, when using pair_style hybrid/scaled. When trying to manually apply /kk suffixes the error changes to Unrecognized pair style 'hybrid/scaled/kk'. When using the otherwise same script with hybrid/overlay no problems occur with and without -sf kokkos.

I don't know whether kokkos acceleration is supposed to work for hybrid/scaled since it is not mentioned in the documentation, but if not the error message is rather irritating.

Files

Attached are the input files used for hybrid/scaled and hybrid/overlay
input.zip
Command to call lammps with kokkos was:

lmp -k on g 1  -sf kk -in lmp.in

[akohlmey]

I don't know whether kokkos acceleration is supposed to work for hybrid/scaled since it is not mentioned in the documentation, but if not the error message is rather irritating.

Since it is not mentioned as an accelerator variant that means it is not supported. All supported functionality is documented. Given the flexible and complex nature of LAMMPS it would be impossible to document all unsupported functionality.

While you may find that error message irritating, it is accurate.

[Leimeroth]

Is support for kokkos acceleration planned? The error message for other accelerator styles is a lot clearer regarding them being not supported imo.
From hybrid/scaled source code for kokkos:

  if (lmp->kokkos && !utils::strmatch(force->pair_style, "^hybrid.*/kk$"))
    error->all(FLERR, "Must use pair_style {}/kk with Kokkos", force->pair_style);

and for other accelerators:

    if ((styles[nstyles]->suffix_flag & (Suffix::INTEL | Suffix::GPU | Suffix::OMP)) != 0)
      error->all(FLERR,
                 "Pair style hybrid/scaled does not support "
                 "accelerator styles");

[akohlmey]

Is support for kokkos acceleration planned?

Not that I know of. That is a question for @stanmoore1

The error message for other accelerator styles is a lot clearer regarding them being not supported imo.

Those tests test for different things and the requirements are different. For KOKKOS the hybrid style must support KOKKOS.

For other accelerated styles that is usually not required (there is no hybrid/gpu or hybrid/omp style but you can use hybrid with GPU or OPENMP sub-styles). Only hybrid/scaled is different since it requires access to data not available with GPU or INTEL package pair styles.

[stanmoore1]

I took a look at pair hybrid/scaled. It wouldn't be hard to port to Kokkos, but I have some other priorities first. So I'll add it to my to-do list, but it could be a little while.

[Leimeroth]

I took a look at pair hybrid/scaled. It wouldn't be hard to port to Kokkos, but I have some other priorities first. So I'll add it to my to-do list, but it could be a little while.

That would be great. Should I keep this open as kind of feature request or close it?