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CMU-CS-97-107
Computer Science Department
School of Computer Science, Carnegie Mellon University
CMU-CS-97-107
Using Optimal Dependency-Trees for Combinatorial
Optimization: Learning the Structure of the Search Space
Shumeet Baluja*, Scott Davies
January 1997
CMU-CS-97-107.ps
Keywords: Combinatorial optimization, dependency trees, probability
models, bayesian networks
Many combinatorial optimization algorithms have no mechanism to
capture inter-parameter dependencies. However, modeling such
dependencies may allow an algorithm to concentrate its sampling more
effectively on regions of the search space which have appeared
promising in the past. We present an algorithm which incrementally
learns second-order probability distributions from good solutions seen
so far, uses these statistics to generate optimal (in terms of maximum
likelihood) dependency trees to model these distributions, and then
stochastically generates new candidate solutions from these trees. We
test this algorithm on a variety of optimization problems. Our results
indicate superior performance over other tested algorithms that either
(1) do not explicitly use these dependencies, or (2) use these
dependencies to generate a more restricted class of dependency graphs.
20 pages
*Justsystem Pittsburgh Research Center, 4616 Henry Street, Pittsburgh,
PA 15213
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