wolffd@0: function engine = bk_ff_hmm_inf_engine(bnet)
wolffd@0: % BK_FF_HMM_INF_ENGINE Naive (HMM-based) implementation of fully factored form of Boyen-Koller 
wolffd@0: % engine = bk_ff_hmm_inf_engine(bnet)
wolffd@0: %
wolffd@0: % This is implemented on top of the forwards-backwards algo for HMMs,
wolffd@0: % so it is *less* efficient than exact inference! However, it is good for educational purposes,
wolffd@0: % because it illustrates the BK algorithm very clearly.
wolffd@0: 
wolffd@0: [persistent_nodes, transient_nodes] = partition_dbn_nodes(bnet.intra, bnet.inter);
wolffd@0: assert(isequal(sort(bnet.observed), transient_nodes));
wolffd@0: [engine.prior, engine.transmat] = dbn_to_hmm(bnet);
wolffd@0: 
wolffd@0: ss = length(bnet.intra);
wolffd@0: 
wolffd@0: engine.bel = [];
wolffd@0: engine.bel_marginals = [];
wolffd@0: engine.marginals = [];
wolffd@0: 
wolffd@0: 
wolffd@0: engine = class(engine, 'bk_ff_hmm_inf_engine', inf_engine(bnet));
wolffd@0: