Tagged “bayesian-networks”

2 articles.

14 September 20263 min readProbabilistic Reasoning

A Hundred Thousand Samples, Four Hundred of Them Real

On the burglary network with both neighbours calling, rejection sampling keeps 183 of 100,000 draws and likelihood weighting keeps all of them at an effective sample size of 396. Both estimates are about 10% off a posterior of 0.284172, and the reason is exactly computable: 252 samples carry 76% of the weight and 99.975% of the squared weight.

Artificial IntelligenceProbability

6 September 20269 min readProbabilistic Reasoning

Bayesian Networks and Probabilistic Inference

How a graph and a few small tables stand in for a joint distribution with thousands of entries, how to answer a query against it exactly by enumeration and variable elimination, and what to do when exact inference is out of reach: rejection sampling, likelihood weighting, and Gibbs sampling, each worked through on the same two networks.

ProbabilityArtificial Intelligence