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diff toolboxes/FullBNT-1.0.7/bnt/CPDs/@tabular_CPD/log_prior.m @ 0:e9a9cd732c1e tip

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first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolboxes/FullBNT-1.0.7/bnt/CPDs/@tabular_CPD/log_prior.m	Tue Feb 10 15:05:51 2015 +0000
@@ -0,0 +1,18 @@
+function L = log_prior(CPD)
+% LOG_PRIOR Return log P(theta) for a tabular CPD 
+% L = log_prior(CPD)
+
+switch CPD.prior_type
+ case 'none',
+  L = 0;
+ case 'dirichlet',
+  D = CPD.dirichlet(:);
+  L = sum(log(D + (D==0)));
+ case 'entropic',
+  % log-prior = log exp(-H(theta)) = sum_i theta_i log (theta_i)
+  fam_sz = CPD.sizes;
+  psz = prod(fam_sz(1:end-1));
+  ssz = fam_sz(end);
+  C = reshape(CPD.CPT, psz, ssz);
+  L = sum(sum(C .* log(C + (C==0))));
+end