private static final void usage()
  {
    System.err.println("usage: java TSP -c <num> [-p] [-m] [-h]");
    System.err.println("    -c number of cities (rounds up to the next power of 2 minus 1)");
    System.err.println("    -p (print the final result)");
    System.err.println("    -m (print informative messages)");
    System.err.println("    -h (print this message)");
    System.exit(0);
  }