Fig. 6.

Comparison of simulation methods. (A) Two typical trajectories each from the SSA (green line) and tau-leap (red dotted line) and ordinary differential equation solutions (black line). The inset shows an enlargement between t = 6.7 and t = 6.9 to highlight the discrete steps of the SSA. (B) Full probability distributions at final time T = 10 generated from 10⁴ simulations of the SSA and tau-leap with step sizes 0.05 and 0.4, compared to the solution of the master equation (from which the SSA is almost indistinguishable). Here X(0) = 250.