A new distributed algorithm for routing network generation in model coupling and its evaluation based on C-Coupler2

Abstract. It is a fundamental functionality of a coupler for Earth system modeling to efficiently handle data transfer between component models. Routing network generation is a major step for initializing the data transfer functionality. Most existing couplers employ an inefficient and unscalable global implementation for routing network generation that relies on collective communications. That’s a main reason why the initialization cost of a coupler increases rapidly when using more processor cores. In this paper, we propose a new Distributed algorithm for Routing network generation (DaRong), which does not introduce any collective communication and achieves much lower complexities than the global implementation. DaRong is of course much more efficient and scalable than the global implementation, which has been further demonstrated via empirical evaluations. DaRong has already been implemented in C-Coupler2. We believe that existing and future couplers can also benefit from it.