Paged Binding Array: Environment Representation for And-Or Parallel Prolog

We show that to exploit both Independent And-and Or-parallelism from Prolog programs independent goals should be recomputed (vs their solutions reused). We present an abstract model, called the Composition-Tree, for representing and-or parallelism in Prolog Programs. The Composition-tree closely mirrors sequential Prolog execution (by recomputing independent goal rather than re-using them). We also present an extension of the Binding Array scheme for And-Or parallel execution of full Prolog based on the Composition-tree. A complete abstract machine for and-or parallel Prolog is presented along with scheduling and memory management issues. We demonstrate why our system is better than the earlier proposals for exploiting and-or parallelism.