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1 function [marginals, fwd, back, loglik] = smooth_evidence(engine, CPDpot, observed, pot_type)
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2 % [marginals, fwd, back, loglik] = smooth_evidence(engine, CPDpot, observed, pot_type) (ff)
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3
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4 error('ff smoothing is broken');
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5
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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 t = 1;
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20 for i=hnodes
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21 fwd{i,t} = CPDpot{i,t};
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22 c = engine.obschild(i);
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23 if 0 % c > 0
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24 fwd{i,t} = multiply_by_pot(fwd{i,t}, CPDpot{c, t});
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25 end
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26 [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
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27 end
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28 logscale(t) = sum(local_logscale);
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29
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30 for t=2:T
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31 for i=hnodes
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32 ps = parents(bnet.dag, i+ss);
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33 assert(all(ps<=ss)); % in previous slice
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34 prior = CPDpot{i,t};
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35 for p=ps(:)'
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36 prior = multiply_by_pot(prior, fwd{p,t-1});
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37 end
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38 fwd{i,t} = marginalize_pot(prior, i+ss);
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39 fwd{i,t} = set_domain_pot(fwd{i,t}, i);
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40 c = engine.obschild(i);
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41 if 0 % c > 0
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42 fwd{i,t} = multiply_by_pot(fwd{i,t}, CPDpot{c,t});
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43 end
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44 [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
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45 end
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46 logscale(t) = sum(local_logscale);
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47 end
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48
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49 loglik = sum(logscale);
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50
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51 back = cell(ss,T);
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52 t = T;
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53 for i=hnodes
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54 pot = dpot(i, ns(i));
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55 cs = children(bnet.intra, i);
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56 for c=cs(:)'
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57 pot = multiply_pots(pot, CPDpot{c,t});
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58 end
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59 back{i,t} = marginalize_pot(pot, i);
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60 back{i,t} = normalize_pot(back{i,t});
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61 back{i,t} = set_domain_pot(back{i,t}, i+ss);
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62 end
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63 for t=T-1:-1:1
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64 for i=hnodes
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65 pot = dpot(i, ns(i));
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66 cs = children(bnet.inter, i);
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67 for c=cs(:)'
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68 pot = multiply_pots(pot, back{c,t+1});
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69 pot = multiply_pots(pot, CPDpot{c,t+1});
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70 end
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71 cs = children(bnet.intra, i);
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72 for c=cs(:)'
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73 pot = multiply_pots(pot, CPDpot{c,t});
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74 end
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75 back{i,t} = marginalize_pot(pot, i);
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76 back{i,t} = normalize_pot(back{i,t});
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77 back{i,t} = set_domain_pot(back{i,t}, i+ss);
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78 end
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79 end
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80
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81
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82 % COMBINE
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83 for t=1:T
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84 for i=hnodes
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85 back{i,t} = set_domain_pot(back{i,t}, i);
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86 fwd{i,t} = multiply_by_pot(fwd{i,t}, back{i,t});
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87 marginals{i,t} = normalize_pot(fwd{i,t});
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88 end
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89 end
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