Efficient and Scalable Initialization of Partitioned Coupled Simulations with preCICE

作     者：Totounferoush, Amin Simonis, Frederic Uekermann, Benjamin Schulte, Miriam 

作者机构：Univ Stuttgart Inst Parallel & Distributed Syst IPVS D-70569 Stuttgart Germany Tech Univ Munich TUM Sci Comp Comp Sci D-85748 Garching Germany 

出 版 物：《ALGORITHMS》 (算法)

年 卷 期：2021年第14卷第6期

页      面：166-166页

核心收录：

学科分类：0301[法学-法学] 03[法学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy [EXC 2075-390740016, 391150578] International Graduate Research Group on "Soft Tissue Robotics" [GRK 2198/1, 1648] European Union Competence Network for Scientific High Performance Computing in Bavaria (KONWIHR) 

主　　题：parallel programming high performance computing multi-physics simulation 

摘      要：preCICE is an open-source library, that provides comprehensive functionality to couple independent parallelized solver codes to establish a partitioned multi-physics multi-code simulation environment. For data communication between the respective executables at runtime, it implements a peer-to-peer concept, which renders the computational cost of the coupling per time step negligible compared to the typical run time of the coupled codes. To initialize the peer-to-peer coupling, the mesh partitions of the respective solvers need to be compared to determine the point-to-point communication channels between the processes of both codes. This initialization effort can become a limiting factor, if we either reach memory limits or if we have to re-initialize communication relations in every time step. In this contribution, we remove two remaining bottlenecks: (i) We base the neighborhood search between mesh entities of two solvers on a tree data structure to avoid quadratic complexity, and (ii) we replace the sequential gather-scatter comparison of both mesh partitions by a two-level approach that first compares bounding boxes around mesh partitions in a sequential manner, subsequently establishes pairwise communication between processes of the two solvers, and finally compares mesh partitions between connected processes in parallel. We show, that the two-level initialization method is fives times faster than the old one-level scheme on 24,567 CPU-cores using a mesh with 628,898 vertices. In addition, the two-level scheme is able to handle much larger computational meshes, since the central mesh communication of the one-level scheme is replaced with a fully point-to-point mesh communication scheme.