- add numpy array (?) of int (`subregion_index`) with subregion index + dict (?) mapping labels to integers (`subregion_`) - shape of that array must match mesh.n - initialise array like field::value and field::norm - keep support for old subregions dictionary - automatically translate legacy subregions into new array - no support to access subfields based on subregion labels defined outside the dictionary (show example in the documentation instead) - add support in mumax3c and later oommfc - review plotting routines
