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Diffstat (limited to 'sourcecodes/bnt-master/BNT/examples/dynamic/viterbi1.m')
| -rw-r--r-- | sourcecodes/bnt-master/BNT/examples/dynamic/viterbi1.m | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/sourcecodes/bnt-master/BNT/examples/dynamic/viterbi1.m b/sourcecodes/bnt-master/BNT/examples/dynamic/viterbi1.m new file mode 100644 index 00000000..6ad07d91 --- /dev/null +++ b/sourcecodes/bnt-master/BNT/examples/dynamic/viterbi1.m @@ -0,0 +1,47 @@ +% Compute Viterbi path discrete HMM by different methods + +intra = zeros(2); +intra(1,2) = 1; +inter = zeros(2); +inter(1,1) = 1; +n = 2; + +Q = 2; % num hidden states +O = 2; % num observable symbols + +ns = [Q O]; +dnodes = 1:2; +onodes = [2]; +eclass1 = [1 2]; +eclass2 = [3 2]; +bnet = mk_dbn(intra, inter, ns, 'discrete', dnodes, 'eclass1', eclass1, 'eclass2', eclass2, ... + 'observed', onodes); + +for seed=1:10 +rand('state', seed); +prior = normalise(rand(Q,1)); +transmat = mk_stochastic(rand(Q,Q)); +obsmat = mk_stochastic(rand(Q,O)); +bnet.CPD{1} = tabular_CPD(bnet, 1, prior); +bnet.CPD{2} = tabular_CPD(bnet, 2, obsmat); +bnet.CPD{3} = tabular_CPD(bnet, 3, transmat); + + +% Create a sequence +T = 5; +ev = sample_dbn(bnet, T); +evidence = cell(2,T); +evidence(2,:) = ev(2,:); % extract observed component +data = cell2num(ev(2,:)); + +%obslik = mk_dhmm_obs_lik(data, obsmat); +obslik = multinomial_prob(data, obsmat); +path = viterbi_path(prior, transmat, obslik); + +engine = {}; +engine{end+1} = smoother_engine(jtree_2TBN_inf_engine(bnet)); + +mpe = find_mpe(engine{1}, evidence); + +assert(isequal(cell2num(mpe(1,:)), path)) % extract values of hidden nodes +end |
