Fig. 3

Different viewpoints of swarm systems. We highlight that the interaction space is a general way of viewing these systems. Models of swarm intelligence are commonly used to solve continuous (top) and discrete (bottom) problems that can be represented in the problem space (left). Each model incorporates metaphor-specific aspects such as velocities (first row) and pheromone (second row) in PSO and ACO, respectively, that can be represented in the metaheuristic space (middle). However, regardless of the problem and the metaphor, the actions of individuals are interdependent and depend on the social interaction. The use of the interaction network allows us to represent the swarm social interaction in the interaction space (right), enabling a unified assessment of metaheuristics