wolffd@0: function [marginal, loglik] = marginal_nodes(engine, query) wolffd@0: % MARGINAL_NODES Compute the marginal on the specified query nodes (enumerative_inf) wolffd@0: % [marginal, loglik] = marginal_nodes(engine, query) wolffd@0: wolffd@0: wolffd@0: if isempty(query) & nargout < 2 wolffd@0: marginal.T = 1; wolffd@0: marginal.domain = []; wolffd@0: return; wolffd@0: end wolffd@0: wolffd@0: evidence = engine.evidence; wolffd@0: bnet = bnet_from_engine(engine); wolffd@0: assert(isempty(bnet.cnodes)); wolffd@0: n = length(bnet.dag); wolffd@0: observed = ~isemptycell(evidence); wolffd@0: vals = cat(1,evidence{observed}); wolffd@0: vals = vals(:)'; wolffd@0: ns = bnet.node_sizes; wolffd@0: wolffd@0: sz = ns(query); wolffd@0: T = 0*myones(sz); wolffd@0: p = 0; wolffd@0: for i=1:prod(ns) wolffd@0: inst = ind2subv(ns, i); % i'th instantiation wolffd@0: if isempty(vals) | inst(observed) == vals % agrees with evidence wolffd@0: prob = exp(log_lik_complete(bnet, num2cell(inst(:)))); wolffd@0: p = p + prob; wolffd@0: v = inst(query); wolffd@0: j = subv2ind(sz, v); wolffd@0: T(j) = T(j) + prob; wolffd@0: end wolffd@0: end wolffd@0: wolffd@0: [T, lik] = normalise(T); wolffd@0: lik = p; wolffd@0: loglik = log(lik); wolffd@0: wolffd@0: Tsmall = shrink_obs_dims_in_table(T, query, evidence); wolffd@0: marginal.domain = query; wolffd@0: marginal.T = Tsmall;