diff toolboxes/FullBNT-1.0.7/bnt/inference/static/@enumerative_inf_engine/marginal_nodes.m @ 0:e9a9cd732c1e tip

first hg version after svn

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolboxes/FullBNT-1.0.7/bnt/inference/static/@enumerative_inf_engine/marginal_nodes.m	Tue Feb 10 15:05:51 2015 +0000
@@ -0,0 +1,41 @@
+function [marginal, loglik] = marginal_nodes(engine, query)
+% MARGINAL_NODES Compute the marginal on the specified query nodes (enumerative_inf)
+% [marginal, loglik] = marginal_nodes(engine, query)
+
+
+if isempty(query) & nargout < 2
+  marginal.T = 1;
+  marginal.domain = [];
+  return;
+end
+
+evidence = engine.evidence;
+bnet = bnet_from_engine(engine);
+assert(isempty(bnet.cnodes));
+n = length(bnet.dag);
+observed = ~isemptycell(evidence);
+vals = cat(1,evidence{observed});
+vals = vals(:)';
+ns = bnet.node_sizes;
+
+sz = ns(query);
+T = 0*myones(sz);
+p = 0;
+for i=1:prod(ns)
+  inst = ind2subv(ns, i); % i'th instantiation
+  if isempty(vals) | inst(observed) == vals % agrees with evidence
+    prob = exp(log_lik_complete(bnet, num2cell(inst(:))));
+    p = p + prob;
+    v = inst(query);
+    j = subv2ind(sz, v);
+    T(j) = T(j) + prob;
+  end
+end
+
+[T, lik] = normalise(T);
+lik = p;
+loglik = log(lik);
+
+Tsmall = shrink_obs_dims_in_table(T, query, evidence);
+marginal.domain = query;
+marginal.T = Tsmall;