V -- Nested Parallelism in C

This paper describes the integration of nested data parallelism into imperative languages using the example of C. Unlike flat data parallelism, nested data parallelism directly provides means for handling irregular data structures and certain forms of control parallelism, such as divide-and-conquer algorithms, thus enabling the programmer to express such algorithms far more naturally. Existing work deals with nested data parallelism in a functional environment, which does help avoid a set of problems, but makes efficient implementations more complicated. Moreover, functional languages are not readily accepted by programmers used to languages, such as Fortran and C, which are currently predominant in programming parallel machines. In this paper, we introduce the imperative data-parallel language V and give an overview of its implementation