Maximum likelihood estimation in Gaussian AMP chain graph models and Gaussian ancestral graph models
Mathias Drton · 2004
The AMP Markov property is a recently proposed alternative Markov property for chain graphs. In the case of continuous variables with a joint multivariate Gaussian distribution, it is the AMP rather than the earlier introduced LWF Markov property that is coherent with data-generation by natural block-recursive regressions. In this paper, we show that maximum likelihood estimates in Gaussian AMP chain graph models can be obtained by combining generalized least squares and iterative proportional fitting to an iterative algorithm. In an appendix, we give useful convergence results for iterative partial maximization algorithms that apply in particular to the described algorithm. Key words: AMP chain graph, graphical model, iterative partial maximization, multivariate normal distribution, maximum likelihood estimation 1