comparison toolboxes/FullBNT-1.0.7/bnt/CPDs/@deterministic_CPD/deterministic_CPD.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function CPD = deterministic_CPD(bnet, self, fname, pfail)
+% DETERMINISTIC_CPD Make a tabular CPD representing a (noisy) deterministic function
+%
+% CPD = deterministic_CPD(bnet, self, fname)
+% This calls feval(fname, pvals) for each possible vector of parent values.
+% e.g., suppose there are 2 ternary parents, then pvals = 
+%  [1 1], [2 1], [3 1],   [1 2], [2 2], [3 2],   [1 3], [2 3], [3 3]
+% If v = feval(fname, pvals(i)), then
+%  CPD(x | parents=pvals(i)) = 1 if x==v, and = 0 if x<>v
+% e.g., suppose X4 = X2 AND (NOT X3). Then
+%    bnet.CPD{4} = deterministic_CPD(bnet, 4, inline('((x(1)-1) & ~(x(2)-1)) + 1'));  
+% Note that x(1) refers pvals(1) = X2, and x(2) refers to pvals(2)=X3
+% See also boolean_CPD.
+%
+% CPD = deterministic_CPD(bnet, self, fname, pfail)
+% will put probability mass 1-pfail on f(parents), and distribute pfail over the other values.
+% This is useful for simulating noisy deterministic functions.
+% If pfail is omitted, it is set to 0.
+%
+
+
+if nargin==0
+  % This occurs if we are trying to load an object from a file.
+  CPD = tabular_CPD(bnet, self);
+  return;
+elseif isa(bnet, 'deterministic_CPD')
+  % This might occur if we are copying an object.
+  CPD = bnet;
+  return;
+end
+
+if nargin < 4, pfail = 0; end
+
+ps = parents(bnet.dag, self);
+ns = bnet.node_sizes;
+psizes = ns(ps);
+self_size = ns(self);
+
+psucc = 1-pfail;
+
+CPT = zeros(prod(psizes), self_size);
+pvals = zeros(1, length(ps));
+for i=1:prod(psizes)
+  pvals = ind2subv(psizes, i);
+  x = feval(fname, pvals);
+  %fprintf('%d ', [pvals x]); fprintf('\n');
+  if psucc == 1
+    CPT(i, x) = 1;
+  else
+    CPT(i, x) = psucc;
+    rest = mysetdiff(1:self_size, x);
+    CPT(i, rest) = pfail/length(rest);
+  end
+end
+CPT = reshape(CPT, [psizes self_size]);  
+
+CPD = tabular_CPD(bnet, self, 'CPT',CPT, 'clamped',1);
+
+