The vast majority of random processes in the real world have no memory ‎- the next step in their development depends purely on their current state‎.‎ Stochastic realizations are therefore defined purely in terms of successive event‎-time pairs‎,‎ and such systems are easy to simulate irrespective of their degree of complexity‎.‎ However‎,‎ whilst the associated probability equations are straightforward to write down‎,‎ their solution usually requires the use of approximation and perturbation