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