Mauch MIREX 2010

function [P, p] = prob_node(CPD, self_ev, pev)

% PROB_NODE Compute prod_m P(x(i,m)| x(pi_i,m), theta_i) for node i (discrete)

% [P, p] = prob_node(CPD, self_ev, pev)

%

% self_ev(m) is the evidence on this node in case m.

% pev(i,m) is the evidence on the i'th parent in case m (if there are any parents).

% (These may also be cell arrays.)

%

% p(m) = P(x(i,m)| x(pi_i,m), theta_i) 

% P = prod p(m)

if iscell(self_ev), usecell = 1; else usecell = 0; end

ncases = length(self_ev);

sz = dom_sizes(CPD);

nparents = length(sz)-1;

if nparents == 0

  assert(isempty(pev));

else

  assert(isequal(size(pev), [nparents ncases]));

end

n = length(sz);

dom = 1:n;

p = zeros(1, ncases);

if isa(CPD, 'tabular_CPD')

  % speed up by looking up CPT using index Zhang Yimin  2001-12-31

  if usecell

    if nparents == 0

      data = [cell2num(self_ev)]; 

    else

      data = [cell2num(pev); cell2num(self_ev)]; 

    end

  else

    if nparents == 0

      data = [self_ev];

    else

      data = [pev; self_ev];

    end

  end

  indices = subv2ind(sz, data'); % each row of data' is a case 

  CPT=CPD_to_CPT(CPD);

  p = CPT(indices);

  %get the prob list

  %cpt_size = prod(sz);

  %prob_list=reshape(CPT, cpt_size, 1);

  %for m=1:ncases  %here we assume we get evidence for node and all its parents

  %  idx=indices(m);

  %  p(m)=prob_list(idx); 

  %end

else % eg. softmax

  for m=1:ncases

    if usecell

      if nparents == 0

	evidence = {self_ev{m}};

      else

	evidence = cell(1,n);

	evidence(1:n-1) = pev(:,m);

	evidence(n) = self_ev(m);

      end

    else

      if nparents == 0

	evidence = num2cell(self_ev(m));

      else

	evidence = num2cell([pev(:,m)', self_ev(m)]);

      end

    end

    T = convert_to_table(CPD, dom, evidence);

    p(m) = T;

  end

end

P = prod(p);