comparison toolboxes/FullBNT-1.0.7/bnt/general/linear_gaussian_to_cpot.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function pot = linear_gaussian_to_cpot(mu, Sigma, W, domain, ns, cnodes, evidence)
+% LINEAR_GAUSSIAN_TO_CPOT Convert a linear Gaussian CPD  to a canonical potential.
+% pot = linear_gaussian_to_cpot(mu, Sigma, W, domain, ns, cnodes, evidence)
+%
+% We include any cts evidence, but ignore any discrete evidence.
+% (Use gaussian_CPD_params_given_dps to use discrete evidence to select mu, Sigma, W.)
+
+odom = domain(~isemptycell(evidence(domain)));
+hdom = domain(isemptycell(evidence(domain)));
+cobs = myintersect(cnodes, odom);
+chid = myintersect(cnodes, hdom);
+cvals = cat(1, evidence{cobs});
+
+%[g,h,K] = gaussian_to_canonical(mu, Sigma, W);
+Sinv = inv(Sigma);
+g = -0.5*mu'*Sinv*mu + log(normal_coef(Sigma));
+if isempty(W) | (size(W,2)==0)  % no cts parents
+  h = Sinv*mu;
+  K = Sinv;
+else
+  h = [-W'*Sinv*mu; Sinv*mu];
+  K = [W'*Sinv*W  -W'*Sinv';
+       -Sinv*W     Sinv]; 
+end
+
+if ~isempty(cvals)
+  %[g, h, K] = enter_evidence_canonical(g, h, K, chid, cobs, cvals(:), ns);  
+  [hx, hy, KXX, KXY, KYX, KYY] = partition_matrix_vec(h, K, chid, cobs, ns);
+  y = cvals(:);
+  g = g + hy'*y - 0.5*y'*KYY*y;
+  if length(hx)==0 % isempty(X) % i.e., we have instantiated everything away
+    h = [];
+    K = [];
+  else
+    h = hx - KXY*y;
+    K = KXX;
+  end
+end
+
+ns(odom) = 0;
+pot = cpot(domain, ns(domain), g, h, K);
+
+