Benchmarks of the code COALA to solve the Smoluchowski coagulation equation (Eq. (1)) with the constant and the additive kernels. In the two plots, the y-axis are the dust grain mass distribution and the x-axis the grain masses in dimensionless unit. The mass range is chosen in order to have 19 orders of magnitude in mass similar to the mass range obtained from s_min = 5 nm to s_max = 1 nm. The black lines are the initial mass distribution. The blue lines are the exact solutions at a final time t_final. The green circle are the numerical solutions for which the mass range is sampled in 40 mass bins. The numerical solutions follow accurately the exact solutions.