Reviewing the source code of the SLURM sluster scheduler I happened on a file “skilling.c”. I thought it could not be! But it indeed refers to John Skilling and it is a portion of the BayeSys3 program (fully credited of course) to convert between integers and rectilinear positions using Hamiltonian space-filling curve. The code is in file slurm/contribs/skilling.c (github) and can be used to convert 2d or 3d positions to linear dimensions in order to have a good linear numbering for nodes which may be connected in a 2d or 3d network topology.

E.g.:

b.nikolic@ip:~/slurm/contribs$ ./skilling  1 2 3
Axis coordinates = 1 2 3
Hilbert integer  = 22 (000000000010110)