Making a dataparallel language portable for massively parallel array computers

A key goal in language design is to simultaneously achieve portability and efficiency. Achieving a general solution to this problem is quite difficult: virtually all attempts have emphasized one or the other requirement by restricting either the architecture domain, the application domain, or both. In this study we present (i) a framework that explains why meeting these requirements simultaneously is so difficult, and (ii) our approach, which, though it may not be the final word on this subject, implements a new set of trade-offs that may come closer to a balanced solution than has been previously achieved. Our solution includes an easy to use language based on the dataparallel programmer's model, a compiler that hides as many machine variations as possible, a library with emulations of constructs that map directly to hardware on some but not all machines, and a library with different versions of those critical application functions for which a single algorithm is not optimal across all hardware configurations. We have found the programmer cost for the application and architecture domains considered here to be quite reasonable.