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annotate toolboxes/FullBNT-1.0.7/bnt/CPDs/@gaussian_CPD/sample_node.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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wolffd@0 1 function y = sample_node(CPD, pev)
wolffd@0 2 % SAMPLE_NODE Draw a random sample from P(Xi | x(pi_i), theta_i) (gaussian)
wolffd@0 3 % y = sample_node(CPD, parent_evidence)
wolffd@0 4 %
wolffd@0 5 % pev{i} is the value of the i'th parent (if there are any parents)
wolffd@0 6 % y is the sampled value (a scalar or vector)
wolffd@0 7
wolffd@0 8 if length(CPD.dps)==0
wolffd@0 9 i = 1;
wolffd@0 10 else
wolffd@0 11 dpvals = cat(1, pev{CPD.dps});
wolffd@0 12 i = subv2ind(CPD.sizes(CPD.dps), dpvals(:)');
wolffd@0 13 end
wolffd@0 14
wolffd@0 15 if length(CPD.cps) == 0
wolffd@0 16 y = gsamp(CPD.mean(:,i), CPD.cov(:,:,i), 1);
wolffd@0 17 else
wolffd@0 18 pev = pev(:);
wolffd@0 19 x = cat(1, pev{CPD.cps});
wolffd@0 20 y = gsamp(CPD.mean(:,i) + CPD.weights(:,:,i)*x(:), CPD.cov(:,:,i), 1);
wolffd@0 21 end
wolffd@0 22 y = y(:);