Mauch MIREX 2010

function pi = CPD_to_pi(CPD, msg_type, n, ps, msg, evidence)

% CPD_TO_PI Compute the pi vector (gaussian)

% function pi = CPD_to_pi(CPD, msg_type, n, ps, msg, evidence)

switch msg_type

 case 'd',

  error('gaussian_CPD can''t create discrete msgs')

 case 'g',

  [m, Q, W] = gaussian_CPD_params_given_dps(CPD, [ps n], evidence);

  cps = ps(CPD.cps);

  cpsizes = CPD.sizes(CPD.cps);

  pi.mu = m;

  pi.Sigma = Q;

  for k=1:length(cps) % only get pi msgs from cts parents

    %bk = block(k, cpsizes);

    bk = CPD.cps_block_ndx{k};

    Bk = W(:, bk);

    m = msg{n}.pi_from_parent{k}; 

    pi.Sigma = pi.Sigma + Bk * m.Sigma * Bk';

    pi.mu = pi.mu + Bk * m.mu; % m.mu = u(k)

  end

end