annotate toolboxes/FullBNT-1.0.7/bnt/general/Old/calc_mpe_dbn.m @ 0:e9a9cd732c1e tip

first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
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wolffd@0 1 function [mpe, ll] = calc_mpe_dbn(engine, evidence, break_ties)
wolffd@0 2 % CALC_MPE Computes the most probable explanation of the evidence
wolffd@0 3 % [mpe, ll] = calc_mpe_dbn(engine, evidence, break_ties)
wolffd@0 4 %
wolffd@0 5 % INPUT
wolffd@0 6 % engine must support max-propagation
wolffd@0 7 % evidence{i,t} is the observed value of node i in slice t, or [] if hidden
wolffd@0 8 %
wolffd@0 9 % OUTPUT
wolffd@0 10 % mpe{i,t} is the most likely value of node i (cell array!)
wolffd@0 11 % ll is the log-likelihood of the globally best assignment
wolffd@0 12 %
wolffd@0 13 % This currently only works when all hidden nodes are discrete
wolffd@0 14
wolffd@0 15 if nargin < 3, break_ties = 0; end
wolffd@0 16
wolffd@0 17 if break_ties
wolffd@0 18 disp('warning: break ties is ignored')
wolffd@0 19 end
wolffd@0 20
wolffd@0 21 [engine, ll] = enter_evidence(engine, evidence, 'maximize', 1);
wolffd@0 22
wolffd@0 23 observed = ~isemptycell(evidence);
wolffd@0 24 [ss T] = size(evidence);
wolffd@0 25 scalar = 1;
wolffd@0 26 N = length(evidence);
wolffd@0 27 mpe = cell(ss,T);
wolffd@0 28 bnet = bnet_from_engine(engine);
wolffd@0 29 ns = bnet.node_sizes;
wolffd@0 30 for t=1:T
wolffd@0 31 for i=1:ss
wolffd@0 32 m = marginal_nodes(engine, i, t);
wolffd@0 33 % observed nodes are all set to 1 inside the inference engine, so we must undo this
wolffd@0 34 if observed(i,t)
wolffd@0 35 mpe{i,t} = evidence{i,t};
wolffd@0 36 else
wolffd@0 37 assert(length(m.T) == ns(i));
wolffd@0 38 mpe{i,t} = argmax(m.T);
wolffd@0 39 end
wolffd@0 40 end
wolffd@0 41 end