Efficient Data Redistribution Algorithms From Irregular to Block Cyclic Data Distribution
Shengguo Li, Hao Jiang, Dezun Dong, Chun Huang, Jie Liu, Xia Liao, Xuguang Chen · IEEE Transactions on Parallel and Distributed Systems · 2022
In this paper, we propose some efficient data redistribution algorithms for redistributing matrices from 1D or 2D irregular format to block cyclic data distribution (BCDD) format, which can be much faster than the BLACS routinePXGEMR2D. These algorithms can be used to combine direct methods with iterative methods. The proposed algorithms divide the communication into two phases: one for processes in the same column and the other for processes in the same row, and the whole data redistribution task is divided into several independent sub-communications. The communication time can be reduced a lot compared with BLACS. Performance results show that our algorithms can be$2\times$–$5\times$faster than the BLACS routinePXGEMR2Dwhen using 4096 processes and the experiments are performed on Tianhe-2A supercomputer.