Daniel@0: function [P, p] = prob_node(CPD, self_ev, pev)
Daniel@0: % PROB_NODE Compute prod_m P(x(i,m)| x(pi_i,m), theta_i) for node i (discrete)
Daniel@0: % [P, p] = prob_node(CPD, self_ev, pev)
Daniel@0: %
Daniel@0: % self_ev(m) is the evidence on this node in case m.
Daniel@0: % pev(i,m) is the evidence on the i'th parent in case m (if there are any parents).
Daniel@0: % (These may also be cell arrays.)
Daniel@0: %
Daniel@0: % p(m) = P(x(i,m)| x(pi_i,m), theta_i) 
Daniel@0: % P = prod p(m)
Daniel@0: 
Daniel@0: if iscell(self_ev), usecell = 1; else usecell = 0; end
Daniel@0: 
Daniel@0: ncases = length(self_ev);
Daniel@0: sz = dom_sizes(CPD);
Daniel@0: 
Daniel@0: nparents = length(sz)-1;
Daniel@0: if nparents == 0
Daniel@0:   assert(isempty(pev));
Daniel@0: else
Daniel@0:   assert(isequal(size(pev), [nparents ncases]));
Daniel@0: end
Daniel@0: 
Daniel@0: n = length(sz);
Daniel@0: dom = 1:n;
Daniel@0: p = zeros(1, ncases);
Daniel@0: if isa(CPD, 'tabular_CPD')
Daniel@0:   % speed up by looking up CPT using index Zhang Yimin  2001-12-31
Daniel@0:   if usecell
Daniel@0:     if nparents == 0
Daniel@0:       data = [cell2num(self_ev)]; 
Daniel@0:     else
Daniel@0:       data = [cell2num(pev); cell2num(self_ev)]; 
Daniel@0:     end
Daniel@0:   else
Daniel@0:     if nparents == 0
Daniel@0:       data = [self_ev];
Daniel@0:     else
Daniel@0:       data = [pev; self_ev];
Daniel@0:     end
Daniel@0:   end
Daniel@0:   
Daniel@0:   indices = subv2ind(sz, data'); % each row of data' is a case 
Daniel@0:   
Daniel@0:   CPT=CPD_to_CPT(CPD);
Daniel@0:   p = CPT(indices);
Daniel@0:   
Daniel@0:   %get the prob list
Daniel@0:   %cpt_size = prod(sz);
Daniel@0:   %prob_list=reshape(CPT, cpt_size, 1);
Daniel@0:   %for m=1:ncases  %here we assume we get evidence for node and all its parents
Daniel@0:   %  idx=indices(m);
Daniel@0:   %  p(m)=prob_list(idx); 
Daniel@0:   %end
Daniel@0:   
Daniel@0: else % eg. softmax
Daniel@0:   
Daniel@0:   for m=1:ncases
Daniel@0:     if usecell
Daniel@0:       if nparents == 0
Daniel@0: 	evidence = {self_ev{m}};
Daniel@0:       else
Daniel@0: 	evidence = cell(1,n);
Daniel@0: 	evidence(1:n-1) = pev(:,m);
Daniel@0: 	evidence(n) = self_ev(m);
Daniel@0:       end
Daniel@0:     else
Daniel@0:       if nparents == 0
Daniel@0: 	evidence = num2cell(self_ev(m));
Daniel@0:       else
Daniel@0: 	evidence = num2cell([pev(:,m)', self_ev(m)]);
Daniel@0:       end
Daniel@0:     end
Daniel@0:     T = convert_to_table(CPD, dom, evidence);
Daniel@0:     p(m) = T;
Daniel@0:   end
Daniel@0: end
Daniel@0:   
Daniel@0: P = prod(p);
Daniel@0: 
Daniel@0: