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1 function engine = enter_evidence(engine, evidence)
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2
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3 doms = engine.fgraph.doms;
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4 ndoms = length(doms);
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5 ns = engine.fgraph.node_sizes;
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6 obs = find(~isemptycell(evidence));
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7 cobs = myintersect(obs, engine.fgraph.cnodes);
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8 dobs = myintersect(obs, engine.fgraph.dnodes);
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9 ns(cobs) = 0;
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10 ns(dobs) = 1;
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11
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12 % recompute the weight of each domain now that we know what nodes are observed
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13 for i=1:ndoms
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14 engine.dom_weight(i) = prod(ns(engine.fgraph.doms{i}));
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15 end
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16
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17 % prime each local kernel with evidence (if any)
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18 local_kernel = cell(1, ndoms);
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19 for i=1:length(engine.fgraph.kernels_of_type)
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20 u = engine.fgraph.kernels_of_type{i};
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21 local_kernel(u) = kernel_to_dpots(engine.fgraph.kernels{i}, evidence, engine.fgraph.domains_of_type{i});
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22 end
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23
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24 % initialise all msgs to 1s
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25 msg = cell(ndoms, ndoms);
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26 for i=1:ndoms
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27 nbrs = engine.fgraph.nbrs{i};
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28 for j=nbrs(:)'
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29 dom = engine.fgraph.sepset{i,j};
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30 msg{i,j} = dpot(dom, ns(dom));
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31 end
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32 end
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33
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34 prod_of_msg = cell(1, ndoms);
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35 bel = cell(1, ndoms);
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36 old_bel = cell(1, ndoms);
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37
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38 converged = 0;
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39 iter = 1;
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40 while ~converged & (iter <= engine.max_iter)
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41
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42 % each node multiplies all its incoming msgs
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43 for i=1:ndoms
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44 prod_of_msg{i} = dpot(doms{i}, ns(doms{i}));
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45 nbrs = engine.fgraph.nbrs{i};
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46 for j=nbrs(:)'
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47 prod_of_msg{i} = multiply_by_pot(prod_of_msg{i}, msg{j,i});
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48 end
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49 end
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50
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51 % each node computes its local belief
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52 old_bel = bel;
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53 for i=1:ndoms
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54 bel{i} = normalize_pot(multiply_pots(prod_of_msg{i}, local_kernel{i}));
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55 end
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56
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57 % converged?
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58 if iter==1
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59 converged = 0;
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60 else
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61 converged = 1;
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62 for i=1:ndoms
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63 belT = get_params(bel{i}, 'table');
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64 old_belT = get_params(old_bel{i}, 'table');
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65 if ~approxeq(belT, old_belT, engine.tol)
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66 converged = 0;
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67 break;
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68 end
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69 end
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70 end
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71
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72 if ~converged
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73 old_msg = msg;
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74 % each node sends a msg to each of its neighbors
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75 for i=1:ndoms
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76 nbrs = engine.fgraph.nbrs{i};
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77 for j=nbrs(:)'
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78 % multiply all incoming msgs except from j
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79 temp = prod_of_msg{i};
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80 temp = divide_by_pot(temp, old_msg{j,i});
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81 % send msg from i to j
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82 temp = multiply_by_pot(temp, local_kernel{i});
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83 msg{i,j} = normalize_pot(marginalize_pot(temp, engine.fgraph.sepset{i,j}));
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84 end
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85 end
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86 end
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87
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88 iter = iter + 1
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89 end
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90
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91 engine.marginal_domains = bel;
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92 %for i=1:ndoms
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93 %engine.marginal_domains{i} = get_params(bel{i}, 'table');
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94 %end
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