Reuse-centric simulation software architectures

Computer simulation is used for many purposes and is one of the first applications of computer programming. Given this long history and the many intended use of the simulation software written so far, writing about simulation software architectures without an additional strong point of focus would certainly turn into a challenging and endless exercise. In this chapter, our additional point of focus is placed on reuse. In general purpose software engineering (as opposed to simulation software engi- neering), the motivations for reuse have long been advocated and dem- onstrated: lower risks of defects, collective support of potentially larger user community, lower development costs, and so on. In simulation soft- ware architectures, we can also cite business-specific motivations, such as providing a better reproducibility of simulation experiments, or avoiding a complex validation process. In practice, although it is rarely discussed, reuse is a problem that may be considered in two opposite directions: reus- ing and being reused. Accordingly, this chapter is divided into two parts, each geared at one of these two directions. This dichotomy also reflects the dual nature of modeling & simulation (MS the second part is rather intended for experienced simu- lation software developers, that look for ideas and techniques to further improve the design of their more mature simulation software.