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