  A computer algorithm to search symmetries of crystal structures as
implemented in the \texttt{spglib} code is described. An iterative algorithm is
employed to robustly identify space group types tolerating a certain amount of
distortion in the crystal structures. The source code is distributed under the
3-Clause BSD License, a permissive open-source software license. This paper
focuses on the algorithm for identifying the space group symmetry of the
crystal structures.
