## Robust Learning of Fixed-Structure Bayesian Networks in Nearly-Linear Time

Sep 28, 2020 (edited Mar 18, 2021)ICLR 2021 PosterReaders: Everyone
• Keywords: Bayesian networks, robust statistics, learning theory
• Abstract: We study the problem of learning Bayesian networks where an $\epsilon$-fraction of the samples are adversarially corrupted. We focus on the fully-observable case where the underlying graph structure is known. In this work, we present the first nearly-linear time algorithm for this problem with a dimension-independent error guarantee. Previous robust algorithms with comparable error guarantees are slower by at least a factor of $(d/\epsilon)$, where $d$ is the number of variables in the Bayesian network and $\epsilon$ is the fraction of corrupted samples. Our algorithm and analysis are considerably simpler than those in previous work. We achieve this by establishing a direct connection between robust learning of Bayesian networks and robust mean estimation. As a subroutine in our algorithm, we develop a robust mean estimation algorithm whose runtime is nearly-linear in the number of nonzeros in the input samples, which may be of independent interest.
• One-sentence Summary: We give the first nearly-linear time algorithm for the robust learning of fixed-structure Bayesian networks.
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