Gillespie Stochastic Simulation Algorithm

The Gillespie stochastic simulation algorithm is a Monte Carlo algorithm that simulates the time evolution of a chemical system according to its chemical master equation. In this demonstration, the reaction is simulated with variable forward and backward rate constants and initial particle numbers. The demonstration shows the key steps of the Gillespie method. In the top left, the time until the next reaction is drawn from an exponential distribution. In the bottom left, the next reaction step (forward or backward) is randomly chosen based on the propensities of reaction. The plot on the right shows the timecourse of each species . Use the "reaction event" slider to scroll through in time through the reactions that occur.