Although the value of R 2 suggested that the correlation is not so strong due to the dramatic difference among these systems, one can still see the positive correlation between the size of the Hilbert space and and number of walkers. In addition, it can be observed that both the intercept and the slope increases when the target matching error decreases, meaning that the advantage that a reduced pre-factor brings decreases. This is not surprising, as the nature of the calculation would be closer to a deterministic FCI calculation.