function marginal = marginal_family(engine, i, t, add_ev)% MARGINAL_FAMILY Compute the marginal on the specified family  (hmm)% marginal = marginal_nodes(engine, i, t, add_ev)%if nargin < 3, t = 1; endif nargin < 4, add_ev = 0; endbnet = bnet_from_engine(engine);ss = length(bnet.intra);if t==1 fam = family(bnet.dag, i); bigpot = engine.one_slice_marginal{t}; nodes = fam;else  fam = family(bnet.dag, i+ss);  if any(fam <= ss) % family spans 2 slices    bigpot = engine.two_slice_marginal{t-1}; % t-1 and t    nodes = fam + (t-2)*ss;  else    bigpot = engine.one_slice_marginal{t};    nodes = fam-ss + (t-1)*ss;  endendmarginal = pot_to_marginal(marginalize_pot(bigpot, nodes, engine.maximize));if add_ev  marginal = add_ev_to_dmarginal(marginal, engine.evidence, engine.node_sizes);end