Flattening Virtual Simulink Subsystems with Graph Transformation

Abstract. Nowadays embedded systems are often modeled using MATLAB R©, Simulink R © and Stateflow R © to simulate their behavior and facilitate design space exploration. As design progresses, models are increasingly elaborated by grad-ually adding implementation detail. An important elaboration is the execution order of the elements in a model. This execution order is based on a sorted list of all semantic relevant model elements. Therefore, it is fundamental to remove model elements that only have a syntactic implication such as hierarchical levels with no semantic bearing. The corresponding language construct in Simulink is the virtual subsystem. Thus, to create an implementation or to execute a model, Simulink performs a flattening model transformation that eliminates virtual sub-systems. The work presented in this paper raises the level of abstraction of the model transformation by modeling the transformation itself in order to unlock the potential for reuse, platform independence, etc.. To this end, the transforma-tion is implemented by applying graph transformation methods. An analysis of the solution shows the transformation model is proper (e.g., it terminates).