function [marginal, pot] = marginal_nodes(engine, query)% MARGINAL_NODES Compute the marginal on the specified query nodes (belprop)% [marginal, pot] = marginal_nodes(engine, query)%% query must be a subset of a familyif isempty(query)  big_pot = engine.marginal_domains{1}; % pick an arbitrary domainelse  big_pot = engine.marginal_domains{query(end)};   endpot = marginalize_pot(big_pot, query);marginal = pot_to_marginal(pot);