A Bayesian Approach to Tackling Hard Computational Problems
This incremental improvement addresses efficiency issues in solving hard constraint satisfaction problems for researchers and practitioners in computational problem-solving.
The paper tackles the high variance in running times of backtracking search algorithms by proposing a dynamic cutoff strategy using learned Bayesian models to predict trial lengths, showing it can outperform optimal fixed strategies.
We are developing a general framework for using learned Bayesian models for decision-theoretic control of search and reasoningalgorithms. We illustrate the approach on the specific task of controlling both general and domain-specific solvers on a hard class of structured constraint satisfaction problems. A successful strategyfor reducing the high (and even infinite) variance in running time typically exhibited by backtracking search algorithms is to cut off and restart the search if a solution is not found within a certainamount of time. Previous work on restart strategies have employed fixed cut off values. We show how to create a dynamic cut off strategy by learning a Bayesian model that predicts the ultimate length of a trial based on observing the early behavior of the search algorithm. Furthermore, we describe the general conditions under which a dynamic restart strategy can outperform the theoretically optimal fixed strategy.