function Pjj = getcondP(P,m,n,jj,ii,y)
% Pjj(x) = P{ X[jj]=x | X[ii]=y }
if ~isempty(intersect(ii,jj))
  error('ii and jj must not intersect');
end

ljj = length(jj);
dimi = repmat([m],[1 ljj]);
Pjj = zeros(m^ljj,1);

for xi = 1:m^ljj
  x = ind2coord(xi,dimi);
  Pjj(xi) = getPX(P,m,n,[y x],[ii jj]);
end
Pjj = Pjj / (sum(Pjj)+realmin);
return