In Table (A|IJ)| A / ∈|D i , which means that the fast-weighted hole-selection outperforms the fullyweighted one. On the other hand it is very important to guarantee orbitals to be occupied in the particle-selection, for both single and double excitations. This means that only uniform or fully-weighted particle-selection are expected to be performant and explains why unif-fast particle selection for double excitations performs so badly for this system (Table ).