Q-MAC meetings in 2020/2021:

The Final International Symposium has been postponed until further notice.

Q-MAC regular meeting 2020 has been cancelled. 

Read more

Q-MAC Extension on the grounds of excellence

Q-MAC Project has been successfully extended for 1 year

Read more

Publication Detail / Abstract

P.-L. Giscard, Z. Choo, S. J. Thwaite, D. Jaksch

Exact Inference on Gaussian Graphical Models of Arbitrary Topology using Path-Sums

published in the Journal of Machine Learning Research, April 2016
> Full text via publisher
We present the path-sum formulation for exact statistical inference of marginals on Gaussian graphical models of arbitrary topology. The path-sum formulation gives the covariance between each pair of variables as a branched continued fraction of finite depth and breadth. Our method originates from the closed- form resummation of infinite families of terms of the walk-sum representation of the covariance matrix. We prove that the path- sum formulation always exists for models whose covariance matrix is positive definite: i.e. it is valid for both walk-summable and non-walk-summable graphical models of arbitrary topology. We show that for graphical models on trees the path-sum formulation is equivalent to Gaussian belief propagation. We also recover, as a corollary, an existing result that uses determinants to calculate the covariance matrix. We show that the path-sum formulation formulation is valid for arbitrary partitions of the inverse covariance matrix. We give detailed examples demonstrating our results.
< Back