wolffd@0: function bnet = mk_cancer_bnet(CPD_type, p)
wolffd@0: % MK_CANCER_BNET Make the 'Cancer' Bayes net.
wolffd@0: %
wolffd@0: % BNET = MK_CANCER_BNET uses the noisy-or parameters specified in Fig 4a of the UAI98 paper by
wolffd@0: % Friedman, Murphy and Russell, "Learning the Structure of DPNs", p145.
wolffd@0: %
wolffd@0: % BNET = MK_CANCER_BNET('noisyor', p) makes each CPD a noisy-or, with probability p of
wolffd@0: % suppression for each parent; leaks are turned off.
wolffd@0: %
wolffd@0: % BNET = MK_CANCER_BNET('cpt', p) uses random CPT parameters drawn from a Dirichlet(p,p,...)
wolffd@0: % distribution. If p << 1, this is near deterministic; if p >> 1, this is near 1/k.
wolffd@0: % p defaults to 1.0 (uniform distribution).
wolffd@0: %
wolffd@0: % BNET = MK_CANCER_BNET('bool') makes each CPT a random boolean function.
wolffd@0: %
wolffd@0: % In all cases, the root is set to a uniform distribution.
wolffd@0: 
wolffd@0: if nargin == 0
wolffd@0:   rnd = 0;
wolffd@0: else
wolffd@0:   rnd = 1;
wolffd@0: end
wolffd@0: 
wolffd@0: n = 5;
wolffd@0: dag = zeros(n);
wolffd@0: dag(1,[2 3]) = 1;
wolffd@0: dag(2,4) = 1;
wolffd@0: dag(3,4) = 1;
wolffd@0: dag(4,5) = 1;
wolffd@0: 
wolffd@0: ns = 2*ones(1,n);
wolffd@0: bnet = mk_bnet(dag, ns);
wolffd@0:     
wolffd@0: if ~rnd
wolffd@0:   bnet.CPD{1} = tabular_CPD(bnet, 1, [0.5 0.5]);
wolffd@0:   bnet.CPD{2} = noisyor_CPD(bnet, 2, 1.0, 1-0.9);
wolffd@0:   bnet.CPD{3} = noisyor_CPD(bnet, 3, 1.0, 1-0.2);
wolffd@0:   bnet.CPD{4} = noisyor_CPD(bnet, 4, 1.0, 1-[0.7 0.6]);
wolffd@0:   bnet.CPD{5} = noisyor_CPD(bnet, 5, 1.0, 1-0.5);
wolffd@0: else
wolffd@0:   switch CPD_type
wolffd@0:    case 'noisyor',
wolffd@0:     for i=1:n
wolffd@0:       ps = parents(dag, i);
wolffd@0:       bnet.CPD{i} = noisyor_CPD(bnet, i, 1.0, p*ones(1,length(ps)));
wolffd@0:     end
wolffd@0:    case 'bool',
wolffd@0:     for i=1:n
wolffd@0:       bnet.CPD{i} = boolean_CPD(bnet, i, 'rnd');
wolffd@0:     end
wolffd@0:    case 'cpt',
wolffd@0:     for i=1:n
wolffd@0:       bnet.CPD{i} = tabular_CPD(bnet, i, p);
wolffd@0:     end
wolffd@0:    otherwise
wolffd@0:     error(['bad CPD type ' CPD_type]);
wolffd@0:   end
wolffd@0: end
wolffd@0:   
wolffd@0:   
wolffd@0: