function jt = distribute_evidence( cX, jtree, caller, ns )
% receive message
if ~isempty(caller)
  jtree = onemsgpass( caller.id, cX.id, jtree, ns );
end;
% step 1.
%disp(cX.id);
cX.mark = 1;
jtree{1}{cX.id}.mark = 1;
% step 2.
unmarkedNBs = find_unbs( cX, jtree );
% step 3.
if length(unmarkedNBs) > 0,
  for c=unmarkedNBs,
    cluster = jtree{1}{c};
%	disp(cluster.id);
    jtree = distribute_evidence( cluster, jtree, cX, ns );
  end;
end;
jt = jtree;