Experimenting with Parallelism for the Instantiation of ASP Programs

In the last few years, the microprocessors technologies have been definitely moving to multi-core architectures, in order to improve performances as well as reduce power consumption. This makes the real Symmetric MultiProcessing (SMP) finally available even on non-dedicated machines, and paves the way to the development of more scalable softwares. Notably, the recent application of Answer Set Programming (ASP) in different emerging areas, such as knowledge management or information extraction/integration, has been showing that scalability is a crucial issue also for ASP systems. Among the tasks performed by ASP systems, the instantiation process, which consists of generating a variable-free program equivalent to the input one, is one of the most expensive from a computational viewpoint, especially for real-world problems where the input data may be huge. In this paper we experiment with a brand new strategy, that we implemented into the ASP system DLV, exploiting parallelism for the instantiation of ASP programs. The results confirm that the proposed technique significantly improves the performances of the system, particularly for solving real-world problems.