Providing Built-In Counters in a Declarative Dynamic Programming Environment.

D-FLAT is a framework for developing algorithms that solve computational problems by dynamic programming on a tree decomposition of the problem instance. The dynamic programming algorithm is specified by means of Answer-Set Programming ASP, allowing for declarative and succinct specifications. D-FLAT traverses the tree decomposition and calls an ASP system with the provided specification at each tree decomposition node. It is thus crucial that the evaluation of the ASP program is done in an efficient way. As experiments have shown, problems that include weights or more involved arithmetics slow down this step significantly due to the grounding step in ASP, which yields large ground programs in these cases. To overcome this problem, we equip D-FLAT with built-in counters in order to shift certain computations from the ASP side to the internal part of D-FLAT. In this paper, we highlight this new feature and provide empirical benchmarks on weighted versions of the Dominating Set problem showing that our new version increases D-FLAT's robustness and efficiency.