Daniel@0: function check_for_cd_arcs(onodes, cnodes, dag)
Daniel@0: % CHECK_FOR_CD_ARCS Raise an error if there are any C->D links where the C node is hidden.
Daniel@0: % check_for_cd_arcs(onodes, cnodes, dag)
Daniel@0: %
Daniel@0: % We cannot convert the logistic/softmax function (C->D CPD) to a Gaussian potential
Daniel@0: % unless we use the variational approximation discussed in 
Daniel@0: % "A variational approximation for Bayesian networks with discrete and continuous latent
Daniel@0: % variables", K. Murphy, UAI 1999.
Daniel@0: 
Daniel@0: n = length(dag);
Daniel@0: hnodes = mysetdiff(1:n, onodes);
Daniel@0: chid = myintersect(cnodes, hnodes);
Daniel@0: dnodes = mysetdiff(1:n, cnodes);
Daniel@0: for i=chid(:)'
Daniel@0:   dcs = myintersect(children(dag, i), dnodes);
Daniel@0:   if ~isempty(dcs)
Daniel@0:     error(['hidden cts node ' num2str(i) ' has a discrete child']);
Daniel@0:   end
Daniel@0: end
Daniel@0: 
Daniel@0: 
Daniel@0: 
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