Stability and relative variance for the different methods. Stability and relative variance functions for the Poisson τ-leap method (solid line) and RK τ-leap methods with optimal stability regions and bounded relative variance (ψ) with 3 stages (dotted line) and 5 stages (dashed line). Regions fulfilling the bounds on ψ are shown in grey. Square dots correspond to relative variances computed from 106 simulations each. (a), (b): Relative variance bounded by 0.1. (c), (d): Relative variance bounded by 0.25. (e), (f): Relative variance bounded by 0.5.