comparison toolboxes/FullBNT-1.0.7/bnt/inference/static/@jtree_inf_engine/find_mpe.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function mpe = find_mpe(engine, evidence, varargin)
+% FIND_MPE Find the most probable explanation of the data (assignment to the hidden nodes)
+% function mpe = find_mpe(engine, evidence,...)
+%
+% evidence{i} = [] if X(i) is hidden, and otherwise contains its observed value (scalar or column vector).
+%
+% The following optional arguments can be specified in the form of name/value pairs:
+% [default value in brackets]
+%
+% soft    - a cell array of soft/virtual evidence;
+%           soft{i} is a prob. distrib. over i's values, or [] [ cell(1,N) ]
+%
+
+bnet = bnet_from_engine(engine);
+ns = bnet.node_sizes(:);
+N = length(bnet.dag);
+
+engine.evidence = evidence;
+  
+% set default params
+exclude = [];
+soft_evidence = cell(1,N);
+
+% parse optional params
+args = varargin;
+nargs = length(args);
+for i=1:2:nargs
+  switch args{i},
+   case 'soft',    soft_evidence = args{i+1}; 
+   otherwise,  
+    error(['invalid argument name ' args{i}]);       
+  end
+end
+engine.maximize = 1;
+
+onodes = find(~isemptycell(evidence));
+hnodes = find(isemptycell(evidence));
+pot_type = determine_pot_type(bnet, onodes);
+ if strcmp(pot_type, 'cg')
+  check_for_cd_arcs(onodes, bnet.cnodes, bnet.dag);
+end
+
+hard_nodes = 1:N;
+soft_nodes = find(~isemptycell(soft_evidence));
+S = length(soft_nodes);
+if S > 0
+  assert(pot_type == 'd');
+  assert(mysubset(soft_nodes, bnet.dnodes));
+end
+ 
+% Evaluate CPDs with evidence, and convert to potentials  
+pot = cell(1, N+S);
+for n=1:N
+  fam = family(bnet.dag, n);
+  e = bnet.equiv_class(n);
+  if isempty(bnet.CPD{e})
+    error(['must define CPD ' num2str(e)])
+  else
+    pot{n} = convert_to_pot(bnet.CPD{e}, pot_type, fam(:), evidence);
+  end
+end
+
+for i=1:S
+  n = soft_nodes(i);
+  pot{N+i} = dpot(n, ns(n), soft_evidence{n});
+end
+clqs = engine.clq_ass_to_node([hard_nodes soft_nodes]); 
+
+[clpot, seppot] = init_pot(engine, clqs, pot, pot_type, onodes);
+[clpot, seppot] = collect_evidence(engine, clpot, seppot);
+mpe = find_max_config(engine, clpot, seppot, evidence); % instead of distribute evidence