if (!results.empty()) {
// terminate the search if we have sufficent results, and we are
// sure no node still on the queue contains a closer match
double furthestResultOrder = results.back().order();
if (!results.empty()) {
// terminate the search if we have sufficent results, and we are
// sure no node still on the queue contains a closer match
double furthestResultOrder = results.back().order();