Independence in dynamically scheduled logic languages

Resumen

The notion of independence has been used in conventional logic programming as the basis for several optimizations, including program parallelization, intelligent backtracking, and goal reordering. In this paper we extend this notion to logic programming languages with dynamic scheduling. This type of scheduling, in which some calls are dynamically “delayed” until their arguments are sufficiently instantiated, is provided in most practical implementations because it offers advantages for both programming power and declarativeness. We focus on the notion of independence required for ensuring correctness and efficiency of parallelization within the independent and-parallel model. We also provide sufficient conditions for independence which can be evaluated “a-priori” (i.e., at run-time), as is needed in many practical applications.