Maximum likelihood for a known graph

Definition taught in Graphical models, part of Statistical learning

Maximum likelihood for a known graph

Type Definition
Taught in Graphical models
Part Statistical learning
  1. Initialise W=S. This presentation assumes S\succ 0.
  2. Repeat for j=1,\ldots,p until convergence:
    1. Partition W into part A, all but the jth row and column, and part B, the jth row and column.
    2. Solve W_{AA}^{*}\beta^{*}-s_{AB}^{*}=0 for the unconstrained edge parameters \beta^{*}. Obtain \hat\beta by padding \hat\beta^{*} with zeros in the positions of the missing edges.
    3. Update w_{AB}=W_{AA}\hat\beta and the corresponding row w_{BA}=w_{AB}^\top.
  3. In the final cycle for each j, solve for the estimated precision: \hat\theta_{AB}=-\hat\beta\,\hat\theta_{BB} with 1/\hat\theta_{BB}=s_{BB}-w_{AB}^\top\hat\beta.

Used in

See also

Undirected graph · Hammersley–Clifford · A zero precision entry is conditional independence · Graphical lasso · Markov graphs · Graph terminology · Conditional independence · Markov properties and factorisation

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