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

first hg version after svn

+function [engine, ll, niter] = enter_evidence(engine, evidence, varargin)
+% ENTER_EVIDENCE Propagate evidence using belief propagation
+% [engine, ll, niter] = enter_evidence(engine, evidence, ...)
+%
+% The log-likelihood is not computed; ll = 0.
+% niter contains the number of iterations used (if engine.protocol = 'parallel')
+%
+% The following optional arguments can be specified in the form of name/value pairs:
+% [default value in brackets]
+%
+% maximize - 1 means use max-product, 0 means use sum-product [0]
+% exclude  - list of nodes whose potential will not be included in the joint [ [] ]
+%
+% e.g., engine = enter_evidence(engine, ev, 'maximize', 1)
+
+ll = 0;
+exclude = [];
+maximize = 0;
+
+if nargin >= 3
+  args = varargin;
+  nargs = length(args);
+  for i=1:2:nargs
+    switch args{i},
+     case 'exclude', exclude = args{i+1};
+     case 'maximize', maximize = args{i+1};
+     otherwise,
+      error(['invalid argument name ' args{i}]);
+    end
+  end
+end
+
+engine.maximize = maximize;
+
+if ~isempty(engine.filename)
+  engine.fid = fopen(engine.filename, 'w');
+  if engine.fid == 0
+    error(['can''t open ' engine.filename]);
+  end
+else
+  engine.fid = [];
+end
+
+gdl = engine.gdl;
+bnet = bnet_from_engine(engine);
+
+ndoms = length(gdl.doms);
+ns = bnet.node_sizes;
+onodes = find(~isemptycell(evidence));
+pot_type = determine_pot_type(bnet, onodes);
+
+% prime each local kernel with evidence (if any)
+local_kernel = cell(1, ndoms);
+for i=1:ndoms
+  if myismember(i, exclude)
+    local_kernel{i} =  mk_initial_pot(pot_type, gdl.doms{i}, ns, bnet.cnodes, onodes);
+  else
+    e = bnet.equiv_class(i);
+    local_kernel{i} =  convert_to_pot(bnet.CPD{e}, pot_type, gdl.doms{i}(:), evidence);
+  end
+end
+  
+% initialise all msgs to 1s
+msg = cell(ndoms, ndoms);
+for i=1:ndoms
+  nbrs = gdl.nbrs{i};
+  for j=nbrs(:)'
+    dom = gdl.sepset{i,j};
+    msg{i,j} = mk_initial_pot(pot_type, dom, ns, bnet.cnodes, onodes);
+  end
+end
+
+switch engine.protocol
+ case 'parallel', 
+   [engine.marginal_domains, niter] = parallel_protocol(engine, evidence, pot_type, local_kernel, msg);
+ case 'tree',
+  engine.marginal_domains = serial_protocol(engine, evidence, pot_type, local_kernel, msg);
+  niter = 1;
+end
+engine.niter = niter;
+
+%fprintf('just finished %d iterations of belprop\n', niter);
+
+if ~isempty(engine.filename)
+  fclose(engine.fid);
+end