has characteristic is generalization of Gillespie direct algorithm spatial description exact solution Gillespie-like method hierarchical stochastic simulation algorithm 2021-01-25 http://identifiers.org/biosimulators/ibiosim http://identifiers.org/doi/10.3389/fbioe.2014.00055 Fast, memory-efficient method for stochastic simulation of hierarchically organized models, such as a model of a cellular population where each cell in the population is represented by the same species and reactions. JRK hSSA