A Divide-and-Conquer Algorithm for Irregular Redistribution in Parallelizing Compilers

In order to achieve higher load balancing, it is necessary to solve irregular block redistribution problems, which are different from regular block-cyclic redistribution. High Performance Fortran version 2 (HPF-2) provides irregular distribution functionalities, such as GEN_BLOCK and INDIRECT. This paper is devoted to develop an efficient algorithm that attempts to obtain near optimal scheduling while satisfying the conditions of minimal message size of total steps and the minimal number of steps for irregular array redistribution. The algorithm intends to decrease the computation costs by dividing the whole block into sub-blocks and solving the sub-problems accordingly, and then merging them together to get final results. Simulation results show that our algorithm has comparable performance with a relocation algorithm developed previously (H. Yook and M. Park. Proceedings of the IASTED International Conference Parallel and Distributed Computingand Systems, Nov. 3–6, MIT, Boston, USA, 1999).