comparison toolboxes/FullBNT-1.0.7/bnt/examples/dynamic/HHMM/remove_hhmm_end_state.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [transprob, termprob] = remove_hhmm_end_state(A)
+% REMOVE_END_STATE Infer transition and termination probabilities from automaton with an end state
+% [transprob, termprob] = remove_end_state(A)
+%
+% A(i,k,j) = Pr( i->j | Qps=k), where i in 1:Q, j in 1:(Q+1), and Q+1 is the end state
+% This implements the equation in footnote 3 of my NIPS 01 paper,
+% transprob(i,k,j) = \tilde{A}_k(i,j)
+% termprob(k,j) = \tau_k(j)
+%
+% For the top level, the k index is missing.
+
+Q = size(A,1);
+toplevel = (ndims(A)==2);
+if toplevel
+  Qk = 1;
+  A = reshape(A, [Q 1 Q+1]);
+else
+  Qk = size(A, 2);
+end
+
+transprob = A(:, :, 1:Q);
+term = A(:,:,Q+1)'; % term(k,j) = P(Qj -> end | k)
+termprob = term;
+%termprob = zeros(Qk, Q, 2);
+%termprob(:,:,2) = term;
+%termprob(:,:,1) = 1-term;
+
+for k=1:Qk
+  for i=1:Q
+    for j=1:Q
+      denom = (1-termprob(k,i));
+      denom = denom + (denom==0)*eps;
+      transprob(i,k,j) = transprob(i,k,j) / denom;
+    end
+  end    
+end
+
+if toplevel
+  termprob = squeeze(termprob);
+  transprob = squeeze(transprob);
+end