Implementing hybrid simulations that integrate DES+SD in Python

Implementation of hybrid simulation is not well documented, and often obscured behind commercial software packages. Here two implementation approaches for integrating discrete event simulation and systems dynamics are presented in an open, reproducible framework, built with the Ciw library in Python. These two implementation approaches, denoted here by $$DES \subset SD$$DES⊂SD and $$SD \subset DES$$SD⊂DES, correspond to two different process environments for DES+SD hybrid simulations. The models contribute to a collection of accessible and transparent hybrid simulations to be reproduced, scrutinised, built upon, and further developed. This paper also presents discussion on the lessons learned from these implementations, including the appropriateness of the models for different process environments, their ability to capture the full variability of a system, and subtleties in their synchronicity.