Accuracy as measured by the L1 error as a function of simulation runtime in seconds for the different algorithms and timestep criteria, for simulation outputs at t = t_rec. The first three panels show results for the simulations with cell Δτ₀ ≃ 1 and ambient densities n_H = 10   cm^-3 (top left), 100   cm^-3 (top right), and 1000   cm^-3 (centre left). The next three show results for simulations with n_H = 10   cm^-3 and cell Δτ₀ ≃ 3 (centre right), Δτ₀ ≃ 10 (bottom left), and Δτ₀ ≃ 30 (bottom right). Each point represents a timestep criterion with A1 in red, A2 in green, and A3 in blue. The points are numbered according to the timestep criteria (A1 in red, A2 in black, A3 in blue), although not all numbers are readable due to overcrowding.