The CFS and ED Data Distribution Schemes for Sparse Arrays on Distributed Memory Multicomputers

A data distribution scheme of sparse arrays on a distributed memory multicomputer, in general, is composed of three phases, data partition, data distribution, and data compression. In the data partition phase, a global sparse array is partitioned into some local sparse arrays. In the data distribution phase, these local sparse arrays are distributed to processors. In the data compression phase, a local sparse array is compressed by some data compression methods in order to obtain better performance for sparse array operations. To implement the data distribution scheme, methods proposed in the literature first perform the data partition phase, then the data distribution phase, followed by the data compression phase. We called this scheme as Send Followed Compress (SFC) scheme. In this paper, we propose two other data distribution schemes, Compress Followed Send (CFS) and Encoding-Decoding (ED), for sparse array distribution. In the CFS scheme, the data compression phase is performed before the data distribution phase. In the ED scheme, the data compression phase can be divided into two steps, encoding and decoding. The encoding step and the decoding step are performed before and after the data distribution phase, respectively. To evaluate the CFS and the ED schemes, we compare them with the SFC scheme. In theoretical analysis, we analyze the SFC, the CFS, and the ED schemes in terms of the data distribution time and the data compression time. In experimental test, for all test cases, we implemented these schemes on an IBM SP2 parallel machine. From the experimental results, the CFS and the ED schemes outperform the SFC scheme for all test cases. For the CFS and the ED schemes, the ED scheme outperforms the CFS scheme. Index Terms Data distribution schemes, Data compression methods, Partition methods, Sparse ratio, Distributed memory multicomputers 1. The work of this paper was partially supported by NSC under contract NSC90-2213-E-035-019 2. The corresponding author.