First, note that most positive offsets present in the usual representations of periodic graphs are one of either (1, 0, 0), (0, 1, 0) or (0, 0, 1). As a consequence, in the most common cases, there are only three elements in the set of positive translations, which can simply be mapped to the three canonical offsets. This fact serves as a heuristic optimisation for the more general algorithm, by representing all the positive translations in the basis A ∈ 3×3 whose columns are the three first linearly independent positive translations. The reverse transformation will be applied at the end of the algorithm. Overall, this operation is not crucial for the algorithm to work and the input remains a set of translations, but it tends to reduce the denominators of the coefficients of the translations, which is computationally helpful.