Many real-world processes can naturally be modeled as systems of interacting agents.
However, the long-term simulation of such agent-based models is often intractable
when the system becomes too large. In this paper, starting from a stochastic
spatiotemporal agent-based model (ABM), we present a reduced model in terms of
stochastic PDEs that describes the evolution of agent number densities for large
populations while retaining the inherent model stochasticity. We discuss the
algorithmic details of both approaches; regarding the SPDE model, we apply finite
element discretization in space, which not only ensures efficient simulation but also
serves as a regularization of the SPDE. Illustrative examples for the spreading of an
innovation among agents are given and used for comparing ABM and SPDE models.
Keywords
agent-based modeling, model reduction, Dean–Kawasaki model,
SPDEs, finite element method