Dustywave test. Evolution of normalised densities (upper panels) and velocities (lower panels) for one (left panel) and four dust fluids (right panel). The dashed black lines correspond to the analytical solution. The other markers and colours represent the numerical results obtained with the EXP algorithm. We additionally plot the L1 error given by Eq. (33) for the one-dust fluid case as an inset in the bottom left panel using a fixed time step of Δ t=10⁻⁴ for EXP and RK1.