Parallelization Strategies for Spatial Agent-Based Models

• Published in: arXiv.org 2017-04
• Main Authors: Fachada, Nuno, Lopes, Vitor V, Martins, Rui C, Rosa, Agostinho C
• Format: Article
• Language: English
• Subjects: Agent-based models; Computer architecture; Computer memory; Computer simulation; Decision making; Domains; Microprocessors; Population (statistical); Reproducibility; Simulation
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1507.04047

Agent-based modeling (ABM) is a bottom-up modeling approach, where each entity of the system being modeled is uniquely represented as an independent decision-making agent. Large scale emergent behavior in ABMs is population sensitive. As such, the number of agents in a simulation should be able to reflect the reality of the system being modeled, which can be in the order of millions or billions of individuals in certain domains. A natural solution to reach acceptable scalability in commodity multi-core processors consists of decomposing models such that each component can be independently processed by a different thread in a concurrent manner. In this paper we present a multithreaded Java implementation of the PPHPC ABM, with two goals in mind: 1) compare the performance of this implementation with an existing NetLogo implementation; and, 2) study how different parallelization strategies impact simulation performance on a shared memory architecture. Results show that: 1) model parallelization can yield considerable performance gains; 2) distinct parallelization strategies offer specific trade-offs in terms of performance and simulation reproducibility; and, 3) PPHPC is a valid reference model for comparing distinct implementations or parallelization strategies, from both performance and statistical accuracy perspectives.