A spin space group provides a suitable way to fully exploit the symmetry of a
spin arrangement with a negligible spin-orbit coupling. There has been a
growing interest in applying spin symmetry analysis with the spin space group
in the field of magnetism. However, there is no established algorithm to search
for spin symmetry operations of the spin space group. This paper presents an
exhaustive algorithm for determining spin symmetry operations of commensurate
spin arrangements. The present algorithm searches for spin symmetry operations
from the symmetry operations of a corresponding nonmagnetic crystal structure
and determines their spin-rotation parts by solving a Procrustes problem. An
implementation is distributed under a permissive free software license in
spinspg v0.1.1: https://github.com/spglib/spinspg.Comment: The implementation will be released after publicatio