Mercurial > hg > camir-aes2014
view toolboxes/FullBNT-1.0.7/bnt/inference/static/@pearl_inf_engine/private/compute_bel.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
---|---|
date | Tue, 10 Feb 2015 15:05:51 +0000 |
parents | |
children |
line wrap: on
line source
function bel = compute_bel(msg_type, pi, lambda) switch msg_type, case 'd', bel = normalise(pi .* lambda); case 'g', if isinf(lambda.precision) % ignore pi because lambda is completely certain (observed) bel.mu = lambda.mu; bel.Sigma = zeros(length(bel.mu)); % infinite precision => 0 variance elseif all(pi.Sigma==0) % ignore lambda because pi is completely certain (delta fn prior) bel.Sigma = pi.Sigma; bel.mu = pi.mu; elseif all(isinf(pi.Sigma)) % ignore pi because pi is completely uncertain bel.Sigma = inv(lambda.precision); bel.mu = bel.Sigma * lambda.info_state; elseif all(lambda.precision == 0) % ignore lambda because lambda is completely uncertain bel.Sigma = pi.Sigma; bel.mu = pi.mu; else % combine both pi and lambda pi_precision = inv(pi.Sigma); bel.Sigma = inv(pi_precision + lambda.precision); bel.mu = bel.Sigma*(pi_precision * pi.mu + lambda.info_state); end otherwise, error(['unrecognized msg type ' msg_type]) end