We say that a basis matrix M * = (a * , b * , c * ) T is a solution to the indexing problem if for a subset Q ⋆ ⊆ Q with at least k min elements, it holds that ∥M * q -ROUND(M * q)∥ ≤ β for all q ∈ Q ⋆ , where β is the bound on the maximum allowed absolute error mentioned above. That is, we have a basis M * for which all reciprocal spots in Q ⋆ satisfy the Laue condition up to the maximum allowed error. We aim to have solutions that resemble the structure of the given ideal crystal lattice basis M ⋆ 0 , thus if M * differs much from this structure, we do not consider it as a valid solution.