wolffd@0: function [marginals, loglik] = enter_soft_evidence(engine, CPDpot, observed, pot_type, filter)
wolffd@0: % ENTER_SOFT_EVIDENCE Add the specified soft evidence to the network (ff)
wolffd@0: % [marginals, loglik] = enter_soft_evidence(engine, CPDpot, observed, pot_type, filter)
wolffd@0: 
wolffd@0: assert(pot_type == 'd');
wolffd@0: [ss T] = size(CPDpot);
wolffd@0: fwd = cell(ss,T);
wolffd@0: hnodes = engine.hnodes(:)';
wolffd@0: onodes = engine.onodes(:)';
wolffd@0: bnet = bnet_from_engine(engine);
wolffd@0: ns = bnet.node_sizes;
wolffd@0: onodes2 = [onodes onodes+ss];
wolffd@0: ns(onodes2) = 1;
wolffd@0: 
wolffd@0: logscale = zeros(1,T);
wolffd@0: H = length(hnodes);
wolffd@0: local_logscale = zeros(1,ss);
wolffd@0: 
wolffd@0: obschild = zeros(1,ss);
wolffd@0: for i=hnodes
wolffd@0:   ocs = myintersect(children(bnet.dag, i), onodes);
wolffd@0:   assert(length(ocs)==1);
wolffd@0:   obschild(i) = ocs(1);
wolffd@0: end  
wolffd@0:   
wolffd@0: t = 1;
wolffd@0: for i=hnodes
wolffd@0:   fwd{i,t} = CPDpot{i,t};
wolffd@0:   c = obschild(i);
wolffd@0:   temp = pot_to_marginal(CPDpot{c,t}); 
wolffd@0:   ev = dpot(i, ns(i), temp.T);
wolffd@0:   fwd{i,t} = multiply_by_pot(fwd{i,t}, ev);
wolffd@0:   [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
wolffd@0: end
wolffd@0: logscale(t) = sum(local_logscale);
wolffd@0: 
wolffd@0: for t=2:T
wolffd@0:   for i=hnodes
wolffd@0:     ps = parents(bnet.dag, i+ss);
wolffd@0:     assert(all(ps<=ss)); % in previous slice
wolffd@0:     prior = CPDpot{i,t};
wolffd@0:     for p=ps(:)'
wolffd@0:       prior = multiply_by_pot(prior, fwd{p,t-1});
wolffd@0:     end
wolffd@0:     fwd{i,t} = marginalize_pot(prior, i+ss);
wolffd@0:     fwd{i,t} = set_domain_pot(fwd{i,t}, i);
wolffd@0:     c = obschild(i);
wolffd@0:     temp = pot_to_marginal(CPDpot{c,t});
wolffd@0:     ev = dpot(i, ns(i), temp.T);
wolffd@0:     fwd{i,t} = multiply_by_pot(fwd{i,t}, ev);
wolffd@0:     [fwd{i,t}, local_logscale(i)] = normalize_pot(fwd{i,t});
wolffd@0:   end
wolffd@0:   logscale(t) = sum(local_logscale);
wolffd@0: end
wolffd@0: 
wolffd@0: loglik = sum(logscale);
wolffd@0: 
wolffd@0: 
wolffd@0: if filter
wolffd@0:   marginals = fwd;
wolffd@0:   return;
wolffd@0: end
wolffd@0: 
wolffd@0: back = cell(ss,T);
wolffd@0: t = T;
wolffd@0: for i=hnodes
wolffd@0:   back{i,t} = dpot(i, ns(i));
wolffd@0:   back{i,t} = set_domain_pot(back{i,t}, i+ss);
wolffd@0: end
wolffd@0: for t=T-1:-1:1
wolffd@0:   for i=hnodes
wolffd@0:     pot = CPDpot{i,t+1};
wolffd@0:     pot = multiply_by_pot(pot, back{i,t+1});
wolffd@0:     c = obschild(i);
wolffd@0:     temp = pot_to_marginal(CPDpot{c,t+1});
wolffd@0:     ev = dpot(i, ns(i), temp.T);
wolffd@0:     pot = multiply_by_pot(pot, ev);
wolffd@0:     back{i,t} = marginalize_pot(pot, i);
wolffd@0:     back{i,t} = normalize_pot(back{i,t});
wolffd@0:     back{i,t} = set_domain_pot(back{i,t}, i+ss);
wolffd@0:   end
wolffd@0: end
wolffd@0: 
wolffd@0: 
wolffd@0: 
wolffd@0: % COMBINE
wolffd@0: for t=1:T
wolffd@0:   for i=hnodes
wolffd@0:     back{i,t} = set_domain_pot(back{i,t}, i);
wolffd@0:     fwd{i,t} = multiply_by_pot(fwd{i,t}, back{i,t});
wolffd@0:     marginals{i,t} = normalize_pot(fwd{i,t});
wolffd@0:     %fwdback{i,t} = normalize_pot(multiply_pots(fwd{i,t}, back{i,t}));
wolffd@0:   end
wolffd@0: end