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1 function [engine, loglik] = dbn_update_bel(engine, evidence)
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2 % DBN_UPDATE_BEL Update the belief state (bk)
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3 % [engine, loglik] = dbn_update_bel(engine, evidence)
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4 %
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5 % evidence{i,1} contains the evidence on node i in slice t-1
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6 % evidence{i,2} contains the evidence on node i in slice t
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7
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8 oldbel = engine.bel;
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9
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10 ss = size(evidence, 1);
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11 bnet = bnet_from_engine(engine);
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12 CPDpot = cell(1, ss);
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13 for n=1:ss
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14 fam = family(bnet.dag, n, 2);
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15 e = bnet.equiv_class(n, 2);
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16 CPDpot{n} = convert_to_pot(bnet.CPD{e}, engine.pot_type, fam(:), evidence);
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17 end
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18
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19 observed = ~isemptycell(evidence);
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20 onodes2 = find(observed(:));
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21 clqs = [engine.clq_ass_to_cluster(:,1); engine.clq_ass_to_node(:,2)];
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22 pots = [oldbel(:); CPDpot(:)];
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23
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24 [clpot, loglik] = enter_soft_evidence(engine.sub_engine, clqs, pots, onodes2(:), engine.pot_type);
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25
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26 C = length(engine.clusters);
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27 newbel = cell(1,C);
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28 for c=1:C
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29 k = engine.clq_ass_to_cluster(c,2);
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30 cl = engine.clusters{c};
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31 newbel{c} = marginalize_pot(clpot{k}, cl+ss); % extract slice 2 posterior
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32 newbel{c} = set_domain_pot(newbel{c}, cl); % shift back to slice 1 for re-use as prior
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33 end
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34
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35 engine.bel = newbel;
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36 engine.bel_clpot = clpot;
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37 engine.slice1 = 0;
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