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