\(\pi \)HyFlow: formalism, semantics, and applications

Simulation models have been described using different perspectives, or worldviews. In the process interaction world view (PI), every entity is modeled by a sequence of actions describing its life cycle, offering a comprehensive model that groups the events involving each entity. In this paper we describe \(\pi \) $\pi$ HyFlow, a formalism for representing hybrid models using a set of communicating processes. This set is dynamic, enabling processes to be created and destroyed at runtime. Processes are encapsulated into \(\pi \) $\pi$ HyFlow base models and communicate through shared memory. \(\pi \) $\pi$ HyFlow, however, can guarantee modularity by enforcing that models can only communicate by input and output interfaces. \(\pi \) $\pi$ HyFlow extends current PI approaches by providing support for HyFlow concepts of sampling and dense (continuous) outputs, in addition to the more traditional event-based communication. Likewise HyFlow, \(\pi \) $\pi$ HyFlow is a modeling & simulation formalism driven by expressiveness and performance analysis. We present \(\pi \) $\pi$ HyFlow semantics, and several applications to illustrate \(\pi \) $\pi$ HyFlow ability to describe a diversity of systems.