camir-aes2014: toolboxes/FullBNT-1.0.7/bnt/inference/static/@pearl_inf_engine/private/compute

first hg version after svn

rev	line source
wolffd@0	1 function bel = compute_bel(msg_type, pi, lambda)
wolffd@0	2
wolffd@0	3 switch msg_type,
wolffd@0	4 case 'd', bel = normalise(pi .* lambda);
wolffd@0	5 case 'g',
wolffd@0	6 if isinf(lambda.precision) % ignore pi because lambda is completely certain (observed)
wolffd@0	7 bel.mu = lambda.mu;
wolffd@0	8 bel.Sigma = zeros(length(bel.mu)); % infinite precision => 0 variance
wolffd@0	9 elseif all(pi.Sigma==0) % ignore lambda because pi is completely certain (delta fn prior)
wolffd@0	10 bel.Sigma = pi.Sigma;
wolffd@0	11 bel.mu = pi.mu;
wolffd@0	12 elseif all(isinf(pi.Sigma)) % ignore pi because pi is completely uncertain
wolffd@0	13 bel.Sigma = inv(lambda.precision);
wolffd@0	14 bel.mu = bel.Sigma * lambda.info_state;
wolffd@0	15 elseif all(lambda.precision == 0) % ignore lambda because lambda is completely uncertain
wolffd@0	16 bel.Sigma = pi.Sigma;
wolffd@0	17 bel.mu = pi.mu;
wolffd@0	18 else % combine both pi and lambda
wolffd@0	19 pi_precision = inv(pi.Sigma);
wolffd@0	20 bel.Sigma = inv(pi_precision + lambda.precision);
wolffd@0	21 bel.mu = bel.Sigma(pi_precision pi.mu + lambda.info_state);
wolffd@0	22 end
wolffd@0	23 otherwise, error(['unrecognized msg type ' msg_type])
wolffd@0	24 end

Mercurial > hg > camir-aes2014