Daniel@0: % Burglar alarm example
Daniel@0: 
Daniel@0: N = 5;
Daniel@0: dag = zeros(N,N);
Daniel@0: E = 1; B = 2; R = 3; A = 4; C = 5;
Daniel@0: dag(E,[R A]) = 1;
Daniel@0: dag(B,A) = 1;
Daniel@0: dag(A,C)=1;
Daniel@0: 
Daniel@0: % true = state 1, false = state 2
Daniel@0: ns = 2*ones(1,N); % binary nodes
Daniel@0: bnet = mk_bnet(dag, ns);
Daniel@0: 
Daniel@0: bnet.CPD{E} = tabular_CPD(bnet, E, [0.1 0.9]);
Daniel@0: bnet.CPD{B} = tabular_CPD(bnet, B, [0.01 0.99]);
Daniel@0: %bnet.CPD{R} = tabular_CPD(bnet, R, [0.65 0.00001 0.35 0.99999]);
Daniel@0: bnet.CPD{R} = tabular_CPD(bnet, R, [0.65 0.01 0.35 0.99]);
Daniel@0: bnet.CPD{A} = tabular_CPD(bnet, A, [0.95 0.8 0.3 0.001 0.05 0.2 0.7 0.999]);
Daniel@0: bnet.CPD{C} = tabular_CPD(bnet, C, [0.7 0.05 0.3 0.95]);
Daniel@0: 
Daniel@0: 
Daniel@0: engine = jtree_inf_engine(bnet);
Daniel@0: ev  = cell(1,N);
Daniel@0: ev{C} = 1;
Daniel@0: engine = enter_evidence(engine, ev);
Daniel@0: mE = marginal_nodes(engine, E);
Daniel@0: mB = marginal_nodes(engine, B);
Daniel@0: fprintf('P(E|c)=%5.3f, P(B|c)=%5.3f\n', mE.T(1), mB.T(1))
Daniel@0: 
Daniel@0: ev{C} = 1;
Daniel@0: ev{R} = 1;
Daniel@0: engine = enter_evidence(engine, ev);
Daniel@0: mE = marginal_nodes(engine, E);
Daniel@0: mB = marginal_nodes(engine, B);
Daniel@0: fprintf('P(E|c,r)=%5.3f, P(B|c,r)=%5.3f\n', mE.T(1), mB.T(1))
Daniel@0: 
Daniel@0: 
Daniel@0: if 0
Daniel@0: nsamples = 100;
Daniel@0: samples = zeros(nsamples, 5);
Daniel@0: for i=1:nsamples
Daniel@0:   samples(i,:) = cell2num(sample_bnet(bnet))';
Daniel@0: end
Daniel@0: end