Data distribution schemes of 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. 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 call 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 the theoretical analysis, we analyze the SFC, CFS, and ED schemes in terms of the data distribution time and the data compression time. In the experimental test, we implemented these schemes on an IBM SP2 parallel machine. From the experimental results, for most of the test cases, the CFS and ED schemes outperform the SFC scheme. For the CFS and ED schemes, the ED scheme outperforms the CFS scheme for all the test cases.