diff toolboxes/FullBNT-1.0.7/bnt/inference/online/@smoother_engine/find_mpe.m @ 0:e9a9cd732c1e tip

first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
parents
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolboxes/FullBNT-1.0.7/bnt/inference/online/@smoother_engine/find_mpe.m	Tue Feb 10 15:05:51 2015 +0000
@@ -0,0 +1,33 @@
+function mpe = find_mpe(engine, ev)
+% FIND_MPE Find the most probable explanation (Viterbi)
+% mpe = enter_evidence(engine, evidence, ...)
+%
+% evidence{i,t} = [] if if X(i,t) is hidden, and otherwise contains its observed value (scalar or column vector)
+%
+
+mpe = cell(size(ev));
+engine.tbn_engine = set_fields(engine.tbn_engine, 'maximize', 1);
+
+T = size(ev, 2);
+f = cell(1,T);
+b = cell(1,T); % b{t}.clpot{c}
+ll = zeros(1,T);
+[f{1}, ll(1)] = fwd1(engine.tbn_engine, ev(:,1), 1);
+for t=2:T
+  [f{t}, ll(t)] = fwd(engine.tbn_engine, f{t-1}, ev(:,t), t);
+end
+
+if T==1
+  [b{1}, mpe(:,1)] = backT_mpe(engine.tbn_engine, f{1}, ev(:,1), 1);
+else
+  [b{T}, mpe(:,T)] = backT_mpe(engine.tbn_engine, f{T}, ev(:,T-1:T), T);
+  for t=T-1:-1:2
+    [b{t}, mpe(:,t)] = back_mpe(engine.tbn_engine, b{t+1}, f{t}, ev(:,t-1:t), t);
+  end
+  t = 1;
+  [b{t}, mpe(:,t)] = back1_mpe(engine.tbn_engine, b{t+1}, f{t}, ev(:,1), t);
+end
+engine.b = b;
+  
+
+