Mercurial > hg > camir-aes2014
view toolboxes/FullBNT-1.0.7/bnt/inference/static/@pearl_inf_engine/private/parallel_protocol.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
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date | Tue, 10 Feb 2015 15:05:51 +0000 |
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function [msg, niter] = parallel_protocol(engine, evidence, msg) bnet = bnet_from_engine(engine); N = length(bnet.dag); ns = bnet.node_sizes(:); if ~isempty(engine.filename) fid = fopen(engine.filename, 'w'); if fid == 0 error(['could not open ' engine.filename ' for writing']) end else fid = []; end converged = 0; iter = 1; hidden = find(isemptycell(evidence)); bel = cell(1,N); old_bel = cell(1,N); %nodes = mysetdiff(1:N, engine.disconnected_nodes); nodes = find(~engine.disconnected_nodes_bitv); while ~converged & (iter <= engine.max_iter) % Everybody updates their state in parallel for n=nodes(:)' cs_msg = children(engine.msg_dag, n); %msg{n}.lambda = compute_lambda(n, cs, msg); msg{n}.lambda = prod_lambda_msgs(n, cs_msg, msg, engine.msg_type); ps_orig = parents(bnet.dag, n); msg{n}.pi = CPD_to_pi(bnet.CPD{bnet.equiv_class(n)}, engine.msg_type, n, ps_orig, msg, evidence); end changed = 0; if ~isempty(fid) fprintf(fid, 'ITERATION %d\n', iter); end for n=hidden(:)' % this will not contain any disconnected nodes old_bel{n} = bel{n}; bel{n} = compute_bel(engine.msg_type, msg{n}.pi, msg{n}.lambda); if ~isempty(fid) fprintf(fid, 'node %d: %s\n', n, bel_to_str(bel{n}, engine.msg_type)); end if engine.storebel engine.bel{n,iter} = bel{n}; end if (iter == 1) | ~approxeq_bel(bel{n}, old_bel{n}, engine.tol, engine.msg_type) changed = 1; end end %converged = ~changed; converged = ~changed & (iter > 1); % Sonia Leach changed this if ~converged % Everybody sends to all their neighbors in parallel for n=nodes(:)' % lambda msgs to parents ps_msg = parents(engine.msg_dag, n); ps_orig = parents(bnet.dag, n); for p=ps_msg(:)' j = engine.child_index{p}(n); % n is p's j'th child old_msg = msg{p}.lambda_from_child{j}(:); new_msg = CPD_to_lambda_msg(bnet.CPD{bnet.equiv_class(n)}, engine.msg_type, n, ps_orig, ... msg, p, evidence); lam_msg = convex_combination_msg(old_msg, new_msg, engine.momentum, engine.msg_type); msg{p}.lambda_from_child{j} = lam_msg; end % pi msgs to children cs_msg = children(engine.msg_dag, n); for c=cs_msg(:)' j = engine.parent_index{c}(n); % n is c's j'th parent old_msg = msg{c}.pi_from_parent{j}(:); %new_msg = compute_pi_msg(n, cs, msg, c)); new_msg = compute_bel(engine.msg_type, msg{n}.pi, prod_lambda_msgs(n, cs_msg, msg, engine.msg_type, c)); pi_msg = convex_combination_msg(old_msg, new_msg, engine.momentum, engine.msg_type); msg{c}.pi_from_parent{j} = pi_msg; end end iter = iter + 1; end end if fid > 0, fclose(fid); end %niter = iter - 1; niter = iter; %%%%%%%%%% function str = bel_to_str(bel, type) switch type case 'd', str = sprintf('%9.4f ', bel(:)'); case 'g', str = sprintf('%9.4f ', bel.mu(:)'); end %%%%%%% function a = approxeq_bel(bel1, bel2, tol, type) switch type case 'd', a = approxeq(bel1, bel2, tol); case 'g', a = approxeq(bel1.mu, bel2.mu, tol) & approxeq(bel1.Sigma, bel2.Sigma, tol); end %%%%%%% function msg = convex_combination_msg(old_msg, new_msg, old_weight, type) switch type case 'd', msg = old_weight * old_msg + (1-old_weight)*new_msg; case 'g', msg = new_msg; end