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

first hg version after svn

+function bel = tree_protocol(engine, evidence, pot_type, local_kernel, msg)
+
+bnet = bnet_from_engine(engine);
+ns = bnet.node_sizes;
+onodes = find(~isemptycell(evidence));
+
+ndoms = length(engine.gdl.doms);
+prod_of_msg = cell(1, ndoms);
+bel = cell(1, ndoms);
+  
+% collect to root (node to parents)
+for n=engine.postorder
+  % absorb msgs from children
+  prod_of_msg{n} = mk_initial_pot(pot_type, engine.gdl.doms{n}, ns, bnet.cnodes, onodes);
+  for c=children(engine.tree, n)
+    prod_of_msg{n} = multiply_by_pot(prod_of_msg{n}, msg{c,n});
+  end
+  % send msg to parents
+  for p=parents(engine.tree, n)
+    if iter==1
+      temp = prod_of_msg{n};
+    else
+      temp = divide_by_pot(prod_of_msg{n}, old_msg{p,n});
+    end
+    temp = multiply_by_pot(temp, local_kernel{n});
+    temp2 = marginalize_pot(temp, engine.gdl.sepset{n,p}, engine.maximize);
+    %fprintf('%d sends %d\n', n, p);
+    msg{n,p} = normalize_pot(temp2);
+  end
+end
+
+% distribute from root (node to children)
+for n=engine.preorder
+  % absorb from parents
+  %prod_of_msg{n} = mk_initial_pot(pot_type, doms{n}, ns, cnodes, onodes);
+  for p=parents(engine.tree, n)
+    prod_of_msg{n} = multiply_by_pot(prod_of_msg{n}, msg{p,n});
+  end
+  bel{n} = normalize_pot(multiply_pots(prod_of_msg{n}, local_kernel{n}));
+  % send msg to children
+  for c=children(engine.tree, n)
+    temp = divide_by_pot(prod_of_msg{n}, msg{c,n});
+    temp = multiply_by_pot(temp, local_kernel{n});
+    temp2 = marginalize_pot(temp, engine.gdl.sepset{n,c}, engine.maximize);
+    %fprintf('%d sends %d\n', n, c);
+    msg{n,c} = normalize_pot(temp2);
+  end
+end