A Constraint-based Parallel Programming Language

This paper describes the rst results from research on the compilation of constraint systems into task level procedural parallel programs. Algorithms are expressed as constraint systems. A dataaow graph is derived from the constraint system and a set of input variables. The dataaow graph, which exploits the parallelism in the constraints, is mapped to the target language CODE 2.0, which represents parallel computation structures as generalized dependence graphs. Finally, parallel C programs are generated. The granularity of the derived data ow graphs depends upon the complexity of the operations directly represented in the constraint system. To extract parallel programs of appropriate granularity, the following features have been included: (i) modularity, (ii) operations over structured types as primitives, (iii) deenition of sequential C functions. A prototype of the compiler has been implemented. The domain of matrix computations has been targeted for applications. Some examples have been programmed. Initial results are encouraging.