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