Control randomness of the simulations

[barnabemonnot]

What

We use a random number generator from Numpy to generate every random event in the simulation. The generator can be seeded to ensure that the same samples are always drawn, which is important for reproducibility.

How

We need to be able to specify a seed as input to the simulation execution. When the simulation is repeated (e.g., Monte Carlo), we need to keep track of all the seeds that were used.