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1 function engine = jtree_2TBN_inf_engine(bnet, varargin)
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2 % JTREE_ONLINE_INF_ENGINE Online Junction tree inference algorithm for DBNs.
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3 % engine = jtree_online_inf_engine(bnet, ...)
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4 %
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5 % The following optional arguments can be specified in the form of name/value pairs:
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6 % [default value in brackets]
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7 %
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8 % clusters - specifies variables that must be grouped in the 1.5 slice DBN
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9 %
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10 % The same nodes must be observed in every slice.
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11 %
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12 % This uses the forwards interface of slice t-1 plus all of slice t.
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13 % By contrast, jtree_dbn uses all of slice t-1 plus the backwards interface of slice t.
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14 % See my thesis for details.
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15
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16
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17 clusters = {};
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18
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19 args = varargin;
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20 nargs = length(args);
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21 for i=1:2:length(args)
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22 switch args{i},
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23 case 'clusters', clusters = args{i+1};
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24 otherwise, error(['unrecognized argument ' args{i}])
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25 end
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26 end
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27
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28 engine.maximize = 0;
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29 engine.evidence = [];
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30 engine.node_sizes = [];
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31
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32 int = compute_fwd_interface(bnet.intra, bnet.inter);
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33 engine.interface = int;
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34 ss = length(bnet.intra);
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35 engine.nonint = mysetdiff(1:ss, int);
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36 onodes = bnet.observed;
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37
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38 bnet15 = mk_slice_and_half_dbn(bnet, int);
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39
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40 % use unconstrained elimination,
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41 % but force there to be a clique containing both interfaces
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42 clusters(end+1:end+2) = {int, int+ss};
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43 engine.jtree_engine = jtree_inf_engine(bnet15, 'clusters', clusters, 'root', int+ss);
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44 jtree_engine = struct(engine.jtree_engine); % violate object privacy
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45
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46 engine.in_clq = clq_containing_nodes(engine.jtree_engine, int);
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47 engine.out_clq = clq_containing_nodes(engine.jtree_engine, int+ss);
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48 engine.clq_ass_to_node = jtree_engine.clq_ass_to_node;
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49 engine.root = jtree_engine.root_clq;
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50
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51 % Also create an engine just for slice 1
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52 bnet1 = mk_bnet(bnet.intra1, bnet.node_sizes_slice, 'discrete', myintersect(bnet.dnodes,1:ss), ...
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53 'equiv_class', bnet.equiv_class(:,1), 'observed', onodes);
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54 for i=1:max(bnet1.equiv_class)
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55 bnet1.CPD{i} = bnet.CPD{i};
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56 end
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57 engine.jtree_engine1 = jtree_inf_engine(bnet1, 'clusters', {int}, 'root', int);
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58 jtree_engine1 = struct(engine.jtree_engine1); % violate object privacy
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59 engine.int_clq1 = clq_containing_nodes(engine.jtree_engine1, int);
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60 engine.clq_ass_to_node1 = jtree_engine1.clq_ass_to_node;
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61 engine.root1 = jtree_engine1.root_clq;
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62
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63 engine.observed = [onodes onodes+ss];
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64 engine.observed1 = onodes;
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65 engine.pot_type = determine_pot_type(bnet, onodes);
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66 engine.slice_size = bnet.nnodes_per_slice;
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67
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68 engine = class(engine, 'jtree_2TBN_inf_engine', inf_engine(bnet));
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69
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