The precomputed probabilities from equation 14 have the huge advantage that they can be calculated once at the beginning of the calculation. In combination with the alias sampling algorithm the precalculated probabilities allow sampling with O(1) run time cost. This is a typical trade-off between memory and time. The memory requirements can in part be reduced by using read-only, node-shared memory for storing the alias tables. It would be desirable for an excitation generator that particle indices, I, J, and hole indices, A, B, are guaranteed to be occupied and unoccupied in |D i , respectively. Unfor-tunately, sampling according to equation 14, with no reference to the current determinant,