Comparison of graph-based model transformation rules

With model transformations arising to primary development artifacts in Model-Driven Engineering, dedicated tools supporting transformation developers in the development and maintenance of model transformations are strongly required. In this paper, we address the versioning of model transformations, which essentially relies on a basic service for comparing different versions of model transformations, e.g., a local workspace version and the latest version of a repository. Focusing on rule-based model transformations based on graph transformation concepts, we propose to compare such transformation rules using a maximum common subgraph (MCS) algorithm as the underlying matching engine. Although the MCS problem is known as a non-polynomial optimization problem, our research hypothesis is that using an MCS algorithm as a basis for comparing graph-based transformation rules is feasible for real-world model transformations and increases the quality of comparison results compared to standard model comparison algorithms. Experimental results obtained on a benchmark set for model transformation confirm this hypothesis.