  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.
