mk_hmm_obslik_vec.m

来自「Bayes网络工具箱」· M 代码 · 共 33 行

function obslik = mk_obs_lik(engine, evidence, t)
% MK_OBS_LIK Make the observation likelihood vector for one slice (hmm)
% obslik = mk_obs_lik(engine, evidence, t)
%
% If t=1, evidence{i} contains the evidence on node i in slice 1
% Otherwise, evidence{i,1} contains the evidence on node i in slice t-1
%            evidence{i,2} contains the evidence on node i in slice t

bnet = bnet_from_engine(engine);
ns = engine.node_sizes;
ss = length(ns);
Q = prod(ns(engine.hnodes));
obslik = zeros(1,Q);
if t==1
  dom = (1:ss);
else
  dom = (1:ss)+ss;
end
bigpot = dpot(dom, ns(dom));
for i=engine.onodes(:)'
  if t==1
    e = bnet.equiv_class(i,1);
    fam = family(bnet.dag, i);
  else
    e = bnet.equiv_class(i,2);
    fam = family(bnet.dag, i, 2);
  end
  pot = CPD_to_dpot(bnet.CPD{e}, fam, ns, bnet.cnodes, evidence);
  bigpot = multiply_by_pot(bigpot, pot);
end
m = pot_to_marginal(bigpot);
obslik = m.T(:);