AN IMPROVED PARALLEL PREFIX ALGORITHM ON OTIS-MESH

Abstract

Wang and Sahni [4] reported two parallel algorithms for N-point prefix computation on an N-processor OTIS-Mesh optoelectronic computer. The overall time complexity for both SIMS and MIMD models of their first algorithm was shown to be (8 N1/4- 1) electronic moves and 2 OTIS moves. This was further reduced to (7 N1/4- 1) electronic moves and 2 OTIS moves in their second algorithm. We present here an improved parallel algorithm for N-point prefix computation on an N-processor OTIS-Mesh, which needs (5.5 N1/4+ 3) electronic moves and 2 OTIS moves. Our algorithm is based on the general theme of parallel prefix algorithm proposed in [4] but following the data distribution and local prefix computation similar to that of [1].