function s = get_sset(sepset,c1,c2)
found = -1;
for i=1:length(sepset)
  s = sepset{i};
  if( s.c1 == c1 )&( s.c2 == c2 )
    found = 1;
    break;
  elseif( s.c1 == c2 )&( s.c2 == c1 )
    found = 1;
	id = i;
    break;
  end;
end;
assert(found>0,'sepset does not exist');