wolffd@0: function [bel, niter] = parallel_protocol(engine, evidence, pot_type, local_kernel, msg)
wolffd@0: 
wolffd@0: bnet = bnet_from_engine(engine);
wolffd@0: ns = bnet.node_sizes;
wolffd@0: onodes = find(~isemptycell(evidence));
wolffd@0: 
wolffd@0: ndoms = length(engine.gdl.doms);
wolffd@0: prod_of_msg = cell(1, ndoms);
wolffd@0: bel = cell(1, ndoms);
wolffd@0: old_bel = cell(1, ndoms);
wolffd@0: 
wolffd@0: converged = 0;
wolffd@0: iter = 1;
wolffd@0: while ~converged & (iter <= engine.max_iter)
wolffd@0:   
wolffd@0:   % each node multiplies all its incoming msgs and computes its local belief
wolffd@0:   old_bel = bel;
wolffd@0:   for i=1:ndoms
wolffd@0:     prod_of_msg{i} = mk_initial_pot(pot_type, engine.gdl.doms{i}, ns, bnet.cnodes, onodes);
wolffd@0:     nbrs = engine.gdl.nbrs{i};
wolffd@0:     for j=nbrs(:)'
wolffd@0:       prod_of_msg{i} = multiply_by_pot(prod_of_msg{i}, msg{j,i});
wolffd@0:     end
wolffd@0:     bel{i} = normalize_pot(multiply_by_pot(local_kernel{i}, prod_of_msg{i}));
wolffd@0:   end
wolffd@0: 
wolffd@0:   if ~isempty(engine.fid)
wolffd@0:     for i=1:ndoms
wolffd@0:       tmp = pot_to_marginal(bel{i});
wolffd@0:       %fprintf(engine.fid, '%9.7f ', tmp.T(1));
wolffd@0:       fprintf(engine.fid, '%9.7f ', tmp.U(1));
wolffd@0:     end
wolffd@0:     %fprintf(engine.fid, '  U ');
wolffd@0:     %for i=1:ndoms
wolffd@0:     %  tmp = pot_to_marginal(bel{i});
wolffd@0:     %  fprintf(engine.fid, '%9.7f ', tmp.U(1));
wolffd@0:     %end
wolffd@0:     fprintf(engine.fid, '\n');
wolffd@0:   end
wolffd@0: 
wolffd@0:   % converged?
wolffd@0:   if iter==1
wolffd@0:     converged = 0;
wolffd@0:   else
wolffd@0:     converged = 1;
wolffd@0:     for i=1:ndoms
wolffd@0:       if ~approxeq_pot(bel{i}, old_bel{i}, engine.tol)
wolffd@0: 	converged = 0;
wolffd@0: 	break;
wolffd@0:       end
wolffd@0:     end
wolffd@0:   end
wolffd@0: 
wolffd@0:   if ~converged
wolffd@0:     old_msg = msg;
wolffd@0:     % each node sends a msg to each of its neighbors
wolffd@0:     for i=1:ndoms
wolffd@0:       nbrs = engine.gdl.nbrs{i};
wolffd@0:       for j=nbrs(:)'
wolffd@0: 	% multiply all incoming msgs except from j
wolffd@0: 	temp = prod_of_msg{i};
wolffd@0: 	temp = divide_by_pot(temp, old_msg{j,i});
wolffd@0: 	% send msg from i to j
wolffd@0: 	temp = multiply_by_pot(temp, local_kernel{i});
wolffd@0: 	temp2 = marginalize_pot(temp, engine.gdl.sepset{i,j}, engine.maximize);
wolffd@0: 	msg{i,j} = normalize_pot(temp2);
wolffd@0:       end
wolffd@0:     end
wolffd@0:   end
wolffd@0: 
wolffd@0:   iter = iter + 1;
wolffd@0: end
wolffd@0: 
wolffd@0: 
wolffd@0: niter = iter-1;
wolffd@0: 
wolffd@0: if 0
wolffd@0: for i=1:ndoms
wolffd@0:   prod_of_msg{i} = mk_initial_pot(pot_type, engine.gdl.doms{i}, ns, bnet.cnodes, onodes);
wolffd@0:   nbrs = engine.gdl.nbrs{i};
wolffd@0:   for j=nbrs(:)'
wolffd@0:     prod_of_msg{i} = multiply_by_pot(prod_of_msg{i}, msg{j,i});
wolffd@0:   end
wolffd@0:   bel{i} = normalize_pot(multiply_by_pot(local_kernel{i}, prod_of_msg{i}));
wolffd@0: end
wolffd@0: end