DiRong1.0: a distributed implementation for improving routing network generation in model coupling

Abstract

A fundamental functionality of model coupling in an Earth system model is to efficiently handle data transfer between component models. An approach of M×N communication following a routing network has been used widely used for data transfer, and routing network generation becomes a major step required to initialize data transfer functionality. Some existing coupling software such as the Model Coupling Toolkit (MCT) and the existing versions of the Community Coupler (C-Coupler) employ a global implementation of routing network generation that relies on gather–broadcast communications, which can be very inefficient under a case of a large number of processes. This is an important reason why the initialization cost of a coupler increases with the number of processor cores. In this paper, we propose a “distributed implementation for routing network generation, version 1.0” (DiRong1.0), which does not introduce any gather–broadcast communication. Empirical evaluations show that DiRong1.0 is much more efficient than the global implementation. DiRong1.0 has already been implemented in C-Coupler2, and we believe that some other couplers can also benefit from it.