Unfortunately, we do not know of any library that can find symmetries for an input given in arbitrary precision; all existing libraries take approximate positions, and thus return only approximate symmetries. We use the spglib library to this purpose. spglib is a C library, which makes it easy to interface with Julia without sacrificing speed. Since all its inputs and outputs are approximate, the returned symmetries need to be checked against the exact equilibrium placement of the graph to rule out false positives. Because of the imprecision of the input, there might also be some false negatives -that is, some symmetries may be missing -but they do not matter because symmetries can only help to eliminate candidates that are symmetric images of other ones already encountered. Hence, the use of symmetries is purely an optimisation, but it has no influence on the result of the algorithm.