Architecture independent analysis of sorting and list ranking on the hierarchical PRAM model

The authors consider the performance of sorting and list ranking on the hierarchical parallel random access machine (H-PRAM), a model of computation which represents general degrees of locality (neighborhoods of activity), considering communication and synchronization simultaneously. The sorting result gives a significant improvement over that for the LPRAM (local-memory PRAM, i.e. unit-size neighborhoods), matches the best known hypercube algorithms when the H-PRAM's latency parameter l(P) is set to log P, and matches the best possible mesh algorithm when l(P)= square root P. The list ranking algorithm demonstrates fundamental limitations of the H-PRAM for nonoblivious problems which have linear-time sequential algorithms.<>