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1 function [marginals, loglik] = enter_soft_evidence(engine, CPDpot, observed, pot_type, filter)
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2 % ENTER_SOFT_EVIDENCE Add the specified soft evidence to the network (ff)
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3 % [marginals, loglik] = enter_soft_evidence(engine, CPDpot, observed, pot_type, filter)
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4
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5 assert(pot_type == 'd');
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6 [ss T] = size(CPDpot);
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7 fwd = cell(ss,T);
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8 hnodes = engine.hnodes(:)';
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9 onodes = engine.onodes(:)';
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10 bnet = bnet_from_engine(engine);
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11 ns = bnet.node_sizes;
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12 onodes2 = [onodes onodes+ss];
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13 ns(onodes2) = 1;
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14
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15 logscale = zeros(1,T);
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16 H = length(hnodes);
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17 local_logscale = zeros(1,ss);
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18
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19 obschild = zeros(1,ss);
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20 for i=hnodes
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21 ocs = myintersect(children(bnet.dag, i), onodes);
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22 assert(length(ocs)==1);
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23 obschild(i) = ocs(1);
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24 end
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25
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26 t = 1;
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27 for i=hnodes
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28 fwd{i,t} = CPDpot{i,t};
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29 c = obschild(i);
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30 temp = pot_to_marginal(CPDpot{c,t});
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31 ev = dpot(i, ns(i), temp.T);
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32 fwd{i,t} = multiply_by_pot(fwd{i,t}, ev);
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33 [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
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34 end
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35 logscale(t) = sum(local_logscale);
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36
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37 for t=2:T
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38 for i=hnodes
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39 ps = parents(bnet.dag, i+ss);
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40 assert(all(ps<=ss)); % in previous slice
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41 prior = CPDpot{i,t};
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42 for p=ps(:)'
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43 prior = multiply_by_pot(prior, fwd{p,t-1});
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44 end
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45 fwd{i,t} = marginalize_pot(prior, i+ss);
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46 fwd{i,t} = set_domain_pot(fwd{i,t}, i);
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47 c = obschild(i);
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48 temp = pot_to_marginal(CPDpot{c,t});
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49 ev = dpot(i, ns(i), temp.T);
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50 fwd{i,t} = multiply_by_pot(fwd{i,t}, ev);
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51 [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
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52 end
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53 logscale(t) = sum(local_logscale);
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54 end
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55
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56 loglik = sum(logscale);
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57
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58
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59 if filter
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60 marginals = fwd;
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61 return;
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62 end
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63
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64 back = cell(ss,T);
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65 t = T;
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66 for i=hnodes
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67 back{i,t} = dpot(i, ns(i));
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68 back{i,t} = set_domain_pot(back{i,t}, i+ss);
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69 end
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70 for t=T-1:-1:1
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71 for i=hnodes
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72 pot = CPDpot{i,t+1};
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73 pot = multiply_by_pot(pot, back{i,t+1});
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74 c = obschild(i);
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75 temp = pot_to_marginal(CPDpot{c,t+1});
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76 ev = dpot(i, ns(i), temp.T);
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77 pot = multiply_by_pot(pot, ev);
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78 back{i,t} = marginalize_pot(pot, i);
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79 back{i,t} = normalize_pot(back{i,t});
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80 back{i,t} = set_domain_pot(back{i,t}, i+ss);
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81 end
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82 end
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83
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84
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85
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86 % COMBINE
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87 for t=1:T
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88 for i=hnodes
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89 back{i,t} = set_domain_pot(back{i,t}, i);
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90 fwd{i,t} = multiply_by_pot(fwd{i,t}, back{i,t});
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91 marginals{i,t} = normalize_pot(fwd{i,t});
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92 %fwdback{i,t} = normalize_pot(multiply_pots(fwd{i,t}, back{i,t}));
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93 end
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94 end
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