|
wolffd@0
|
1 function [engine, loglik] = enter_evidence(engine, evidence, varargin)
|
|
wolffd@0
|
2 % ENTER_EVIDENCE Add the specified evidence to the network (cond_gauss)
|
|
wolffd@0
|
3 % [engine, loglik] = enter_evidence(engine, evidence, ...)
|
|
wolffd@0
|
4 %
|
|
wolffd@0
|
5 % evidence{i} = [] if if X(i) is hidden, and otherwise contains its observed value (scalar or column vector)
|
|
wolffd@0
|
6
|
|
wolffd@0
|
7 bnet = bnet_from_engine(engine);
|
|
wolffd@0
|
8 ns = bnet.node_sizes(:);
|
|
wolffd@0
|
9 observed = ~isemptycell(evidence);
|
|
wolffd@0
|
10 onodes = find(observed);
|
|
wolffd@0
|
11 hnodes = find(isemptycell(evidence));
|
|
wolffd@0
|
12 engine.evidence = evidence;
|
|
wolffd@0
|
13
|
|
wolffd@0
|
14 % check there are no C->D links where C is hidden
|
|
wolffd@0
|
15 pot_type = determine_pot_type(bnet, onodes);
|
|
wolffd@0
|
16
|
|
wolffd@0
|
17 dhid = myintersect(hnodes, bnet.dnodes);
|
|
wolffd@0
|
18 S = prod(ns(dhid));
|
|
wolffd@0
|
19 T = zeros(S,1);
|
|
wolffd@0
|
20
|
|
wolffd@0
|
21 N = length(bnet.dag);
|
|
wolffd@0
|
22 mu = cell(1,N);
|
|
wolffd@0
|
23 Sigma = cell(1,N);
|
|
wolffd@0
|
24 cobs = myintersect(bnet.cnodes, onodes);
|
|
wolffd@0
|
25 chid = myintersect(bnet.cnodes, hnodes);
|
|
wolffd@0
|
26 ens = ns;
|
|
wolffd@0
|
27 ens(cobs) = 0;
|
|
wolffd@0
|
28 for j=chid(:)'
|
|
wolffd@0
|
29 mu{j} = zeros(ens(j), S);
|
|
wolffd@0
|
30 Sigma{j} = zeros(ens(j), ens(j), S);
|
|
wolffd@0
|
31 end
|
|
wolffd@0
|
32
|
|
wolffd@0
|
33 for i=1:S
|
|
wolffd@0
|
34 dvals = ind2subv(ns(dhid), i);
|
|
wolffd@0
|
35 evidence(dhid) = num2cell(dvals);
|
|
wolffd@0
|
36 [sub_engine, loglik] = enter_evidence(engine.sub_engine, evidence);
|
|
wolffd@0
|
37 for j=chid(:)'
|
|
wolffd@0
|
38 m = marginal_nodes(sub_engine, j);
|
|
wolffd@0
|
39 mu{j}(:,i) = m.mu;
|
|
wolffd@0
|
40 Sigma{j}(:,:,i) = m.Sigma;
|
|
wolffd@0
|
41 end
|
|
wolffd@0
|
42 T(i) = exp(loglik);
|
|
wolffd@0
|
43 end
|
|
wolffd@0
|
44
|
|
wolffd@0
|
45 [T, lik] = normalise(T);
|
|
wolffd@0
|
46 loglik = log(lik);
|
|
wolffd@0
|
47
|
|
wolffd@0
|
48 engine.T = T;
|
|
wolffd@0
|
49 engine.mu = mu;
|
|
wolffd@0
|
50 engine.Sigma = Sigma;
|
|
wolffd@0
|
51
|
|
wolffd@0
|
52 dnodes = bnet.dnodes;
|
|
wolffd@0
|
53 dobs = myintersect(dnodes, onodes);
|
|
wolffd@0
|
54 ens(dobs) = 1;
|
|
wolffd@0
|
55 engine.joint_dmarginal = dpot(dnodes, ens(dnodes), myreshape(engine.T, ens(dnodes)));
|
|
wolffd@0
|
56
|
|
wolffd@0
|
57 engine.onodes = onodes;
|
