Program Transformation to Identify Parallel Skeletons

Programs that operate over recursive data structures may contain potential parallel computations. Writing parallel programs, even when aided by parallel skeletons, is very challenging, requires intricate analysis of the underlying algorithm and often uses inefficient intermediate data structures. Very few automated parallelisation methods that address a wide range of programs and data types exist. In this paper, we present a transformation method for functional programs defined over any recursive data types. Our method encodes the inputs of a program so that the transformed program is more likely to contain instances of polytypic fold skeletons, and less likely to contain inefficient intermediate data structures. With parallel implementations for these skeletons, the transformed programs can potentially be evaluated on hardware such as multi-core CPUs and/or GPUs.