Mauch MIREX 2010

function y = sample_node(CPD, pev)

% SAMPLE_NODE Draw a random sample from P(Xi | x(pi_i), theta_i)  (tabular)

% y = sample_node(CPD, pev)

%

% pev{i} is the value of the i'th parent (if any)

%assert(~any(isemptycell(pev)));

%CPT = CPD_to_CPT(CPD);

%sz = mysize(CPT);

sz = CPD.sizes; 

nparents = length(sz)-1;

if nparents > 0

  pvals = cat(1, pev{:});

end

switch nparents

 case 0, T = CPD.CPT;

 case 1, T = CPD.CPT(pvals(1), :);

 case 2, T = CPD.CPT(pvals(1), pvals(2), :);

 case 3, T = CPD.CPT(pvals(1), pvals(2), pvals(3), :);

 case 4, T = CPD.CPT(pvals(1), pvals(2), pvals(3), pvals(4), :);

 otherwise,

  psz = sz(1:end-1);

  ssz = sz(end);

  i = subv2ind(psz, pvals(:)');

  T = reshape(CPD.CPT, [prod(psz) ssz]);

  T = T(i,:);

end

if sz(end)==2

  r = rand(1,1);

  if r > T(1)

    y = 2;

  else

    y = 1;

  end

else

  y = sample_discrete(T);

end