Daniel@0: function marginal = marginal_nodes(engine, nodes, t)
Daniel@0: % MARGINAL_NODES Compute the marginal on the specified query nodes (ff)
Daniel@0: % marginal = marginal_nodes(engine, i, t)
Daniel@0: % returns Pr(X(i,t) | Y(1:T)), where X(i,t) is the i'th node in the t'th slice.
Daniel@0: % If enter_evidence used filtering instead of smoothing, this will return  Pr(X(i,t) | Y(1:t)).
Daniel@0: 
Daniel@0: if nargin < 3, t = 1; end
Daniel@0: assert(length(nodes)==1);
Daniel@0: i = nodes(end);
Daniel@0: if myismember(i, engine.hnodes)
Daniel@0:   marginal = pot_to_marginal(engine.marginals{i,t});
Daniel@0: else
Daniel@0:   marginal = pot_to_marginal(dpot(i, 1, 1)); % observed
Daniel@0: end
Daniel@0: 
Daniel@0: bnet = bnet_from_engine(engine);
Daniel@0: ss = length(bnet.intra);
Daniel@0: % we convert the domain to the unrolled numbering system
Daniel@0: % so that update_ess extracts the right evidence.
Daniel@0: marginal.domain = nodes+(t-1)*ss;