A Trade-Off Between Simplicity and Robustness? Illustration on a Lattice-Gas Model of Swarming

Abstract

We re-examine a cellular automaton model of swarm formation. The local rule is stochastic and defined simply as a force that aligns particles with their neighbours. This lattice-gas cellular automaton was proposed by Deutsch to mimic the self-organisation process observed in various natural systems (birds, fishes, bacteria, etc.). We explore the various patterns the self-organisation process may adopt. We observe that, according to the values of the two parameters that define the model, the alignment sensitivity and density of particles, the system may display a great variety of patterns. We analyse this surprising diversity of patterns with numerical simulations. We ask where this richness comes from. Is it an intrinsic characteristic of the model or a mere effect of the modelling simplifications?