gpu/cpu mutex naming

cc @conda-forge/core

As we are adding more packages, we have to decide on the naming.

Currently most packages use <pkg>-proc=*=cpu and <pkg>-proc=*=gpu. While it is great to have a uniform naming scheme, I don’t particularly like the -proc name since the name doesn’t mean anything. We should decide on the naming soon.

We can fix already existing packages to work with the new name and the old name if we decide on a new name.

[xhochy]

I would prefer the usage of cuda instead of gpu to reflect the technology used.

[h-vetinari]

Since https://github.com/conda-forge/pytorch-cpu-feedstock/pull/22, that feedstock has the following build strings:

outputs:
  - name: pytorch
    build:
      string: cuda{{ cuda_compiler_version | replace('.', '') }}py{{ CONDA_PY }}h{{ PKG_HASH }}_{{ PKG_BUILDNUM }}  # [cuda_compiler_version != "None"]
      string: cpu_py{{ CONDA_PY }}h{{ PKG_HASH }}_{{ PKG_BUILDNUM }}                                      # [cuda_compiler_version == "None"]

I had asked in that PR:

@h-vetinari: Just checking what the thought was for the build strings here, since I stumbled over them and tracked them down to this PR - I had been thinking about adding the cuda version to the faiss-buildstrings as well: conda-forge/faiss-split-feedstock@53422a1

Perhaps - like for the mutex naming (cf conda-forge/conda-forge.github.io#1059) - there should be a standard way to do this? Speaking of mutexes - if I understand correctly there’s now no “proc” package for pytorch to select the type of installation? Does conda install pytorch=*=cpu still work with the qualifier in front? (wanted to try, but there are no CF packages for windows yet…)

Copying this here because I’d like to have an idea of what should be used before I go forward with the adaptation in https://github.com/conda-forge/faiss-split-feedstock/pull/19.