Regions: An Abstraction for Expressing Array Computation

ion for Expressing Array Computation Bradford L. Chamberlain E Christopher Lewis Calvin Lin y Lawrence Snyder University of Washington, Seattle, WA 98195-2350 y University of Texas, Austin, TX 78712 fbrad,echris,snyderg@cs.washington.edu,lin@cs.utexas.edu February 1, 1999 Abstract Most array languages, such as Fortran 90, Matlab, and APL, provide support for referencing arrays by extending the traditional array subscripting construct found in scalar languages. We present an alternative approach that exploits the concept of regions---a representation of index sets that can be named, manipulated with high-level operators, and syntactically separated from array references. This paper develops the concept of region-based programming and describes its benefits in the context of an idealized array language called RL. We show that regions simplify programming, reduce the likelihood of errors, and enable code reuse. Furthermore, we describe how regions accentuate the locality of array e..