Yes, the actual program is a stochastic simulation using the next reaction method. However, it uses a modified form of NRM that incorporates delayed reactions, such as mRNA transcription. I thought NRM would be faster however if the other algorithms do work better in practice, I’ll try and implement their delayed versions and see how they fare up. I did briefly look at some packages in Julia to see if this algorithm was already built in, such as BioSimulator.jl and DifferentialEquations.jl, but I think those packages don’t have the ability to model reactions with delays.