Daniel@0: function marginal = marginal_nodes(engine, nodes, t)
Daniel@0: % MARGINAL_NODES Compute the marginal on the specified query nodes (kalman)
Daniel@0: % marginal = marginal_nodes(engine, nodes, t)
Daniel@0: %
Daniel@0: % 't' specifies the time slice of the earliest node in 'nodes'.
Daniel@0: % 'nodes' cannot span more than 2 time slices.
Daniel@0: %
Daniel@0: % Example:
Daniel@0: % Consider a DBN with 2 nodes per slice.
Daniel@0: % Then t=2, nodes=[1 3] refers to node 1 in slice 2 and node 1 in slice 3,
Daniel@0: % i.e., nodes 3 and 5 in the unrolled network,
Daniel@0: 
Daniel@0: if nargin < 3, t = 1; end
Daniel@0: 
Daniel@0: bnet = bnet_from_engine(engine);
Daniel@0: ss = length(bnet.intra);
Daniel@0: if all(nodes <= ss)
Daniel@0:   bigpot = engine.one_slice_marginal{t};
Daniel@0: else
Daniel@0:   bigpot = engine.two_slice_marginal{t};
Daniel@0: end
Daniel@0: 
Daniel@0: nodes = nodes + (t-1)*ss;
Daniel@0: pot = marginalize_pot(bigpot, nodes);
Daniel@0: marginal = pot_to_marginal(pot);