Abstract not found

Abstract. Most array operations in Sac are specified in terms of socalled with-loops, a Sac-specific form of array comprehension. Due to the map-like semantics of with-loops its loop instances can be computed in any order which provides considerable freedom when it comes to compiling them into nestings of for-loops in C. This paper discusses several different execution orders and their impact on compilation complexity, size of generated code, and execution runtimes. As a result, a multiply parameterized compilation scheme is proposed which achieves speedups of up to a factor of 16 when compared against a nai"ve compilation scheme. 1 Introduction Sac is a functional C-variant that is particularly aimed at numerical applications involving complex array operations. To allow for a fairly high level of abstraction, Sac supports so-called shape-invariant programming, i.e., all operations/functions can be defined in a way that allows array arguments to have arbitrary extents in an arbitrary number of dimensions. The main language construct for specifying such array operations is the so-called with-loop, a form of array comprehension adjusted to the needs of shape-invariant programming. In [20] it has been shown that the array concept of Sac is suitable for specifying reasonably complex array operations in a shape-invariant style. It has also been shown that such specifications can be compiled into code whose runtimes are competitive with those obtained from rather low-level specifications in other languages such as Sisal or Fortran.