The refinement of high-level parallel algorithm specifications

PSETL is a prototyping language for developing efficient numeric code for massively parallel machines. PSETL enables parallel algorithms to be concisely specified at a very high level, and successively refined into lower level architecture-specific code. It includes a rich variety of parallel loops over sets, bags, and tuples, and a hierarchy of communication mechanisms, ranging from atomic assignments to reductions and scans on collections. We illustrate the parallel features of PSETL and the refinement process using an N-body simulation code as a case study. The high-level code, which is only a few pages long, is refined for execution on shared and disjoint address-space MIMD machines.