comparison toolboxes/FullBNT-1.0.7/bnt/inference/static/@pearl_inf_engine/private/tree_protocol.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function msg = tree_protocol(engine, evidence, msg)
+
+bnet = bnet_from_engine(engine);
+N = length(bnet.dag);
+
+% Send messages from leaves to root
+for i=1:N-1
+  n = engine.postorder(i);
+  above = parents(engine.adj_mat, n);
+  msg = send_msgs_to_some_neighbors(n, msg, above, bnet, engine.child_index, engine.parent_index, ...
+				    engine.msg_type, evidence);
+end
+
+% Process root
+n = engine.root;
+cs = children(bnet.dag, n);
+%msg{n}.lambda = compute_lambda(n, cs, msg, engine.msg_type);
+msg{n}.lambda = prod_lambda_msgs(n, cs, msg, engine.msg_type);
+ps = parents(bnet.dag, n);
+msg{n}.pi = CPD_to_pi(bnet.CPD{bnet.equiv_class(n)}, engine.msg_type, n, ps, msg, evidence);
+
+% Send messages from root to leaves
+for i=1:N
+  n = engine.preorder(i);
+  below = children(engine.adj_mat, n);
+  msg = send_msgs_to_some_neighbors(n, msg, below, bnet, engine.child_index, engine.parent_index, ...
+				    engine.msg_type, evidence);
+end
+
+  
+%%%%%%%%%%
+
+function msg = send_msgs_to_some_neighbors(n, msg, valid_nbrs, bnet, child_index, parent_index, ...
+					   msg_type, evidence)
+
+verbose = 0;
+
+ns = bnet.node_sizes;
+dag = bnet.dag;
+e = bnet.equiv_class(n);
+CPD = bnet.CPD{e};
+
+
+cs = children(dag, n);
+%msg{n}.lambda = compute_lambda(n, cs, msg);
+msg{n}.lambda = prod_lambda_msgs(n, cs, msg, msg_type);
+if verbose, fprintf('%d computes lambda\n', n); display(msg{n}.lambda); end
+
+ps = parents(dag, n);
+msg{n}.pi = CPD_to_pi(CPD, msg_type, n, ps, msg, evidence);
+if verbose, fprintf('%d computes pi\n', n); display(msg{n}.pi); end
+
+ps2 = myintersect(parents(dag, n), valid_nbrs);
+for p=ps2(:)'
+  lam_msg = CPD_to_lambda_msg(CPD, msg_type, n, ps, msg, p, evidence);
+  j = child_index{p}(n); % n is p's j'th child
+  msg{p}.lambda_from_child{j} = lam_msg;
+  if verbose, fprintf('%d sends lambda to %d\n', n, p); display(lam_msg); end
+end
+
+cs2 = myintersect(cs, valid_nbrs);
+for c=cs2(:)'
+  %pi_msg = compute_pi_msg(n, cs, msg, c);
+  pi_msg = compute_bel(msg_type, msg{n}.pi, prod_lambda_msgs(n, cs, msg, msg_type, c));
+  j = parent_index{c}(n); % n is c's j'th parent
+  msg{c}.pi_from_parent{j} = pi_msg;
+  if verbose, fprintf('%d sends pi to %d\n', n, c); display(pi_msg); end
+end
+
+
+