www.pudn.com > HMM1.zip > dhmm_logprob_brute_force.m
function logp = enumerate_HMM_loglik(prior, transmat, obsmat)
> ENUMERATE_HMM_LOGLIK Compute the log likelihood of a sequence by exhaustive (O(Q^T)) enumeration.
> logp = enumerate_HMM_loglik(prior, transmat, obsmat)
>
> Inputs:
> prior(i) = Pr(Q(1) = i)
> transmat(i,j) = Pr(Q(t+1)=j | Q(t)=i)
> obsmat(i,t) = Pr(y(t) | Q(t)=i)
Q = length(prior);
T = size(obsmat, 2);
sizes = repmat(Q, 1, T);
psum = 0;
for i=1:Q^T
qs = ind2subv(sizes, i); > make the state sequence
psum = psum + prob_path(prior, transmat, obsmat, qs);
end
logp = log(psum)