Guided Bottom-up Interactive Constraint Acquisition

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Constraint Acquisition (CA) systems can be used to assist in the modeling of constraint satisfaction problems. In (inter)active CA, the system is given a set of candidate constraints and posts queries to the user with the goal of finding the right constraints among the candidates. Current interactive CA algorithms suffer from at least two major bottlenecks. First, in order to converge, they require a large number of queries to be asked to the user. Second, they cannot handle large sets of candidate constraints, since these lead to large waiting times for the user. For this reason, the user must have fairly precise knowledge about what constraints the system should consider. In this presentation, I discuss how we alleviated these bottlenecks in our CP2023 paper, presenting our two novel methods that improve the efficiency of CA.

I first focused on our new query generation method, namely PQ-GEN, that allows the use of openly accessible CP solvers in query generation. Then, I presented our bottom-up approach named GrowAcq, which reduces the maximum waiting time for the user and allows the system to handle much larger sets of candidate constraints. I finally focused on the probability-based method to guide query generation that we proposed and showed that it can significantly reduce the number of queries required to converge. Experimental results are presented in the end, showing that our proposed methods outperform state-of-the-art CA methods, reducing the number of queries by up to 60%. I also focused on the fact that our methods work well even in cases where the set of candidate constraints is 50 times larger than the ones commonly used in the literature.

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