@Override
 protected void parseArgs(CommandLine cli, String[] args) throws ParseException, HelpException {
   super.parseArgs(cli, args);
   graph_options.parse(cli);
   ext_fmt.parse(cli);
   if (cli.hasOption(maxTimeOption)) maxTime = Long.parseLong(cli.getOptionValue(maxTimeOption));
   dtps = getTicsPerSecond(cli.getOptionValue(destTimeUnitOption, "s"));
   if (dtps == null) throw new HelpException();
   d_interval = Double.parseDouble(cli.getOptionValue(intervalOption, "1"));
 }
 @Override
 protected void parseArgs(CommandLine cli, String[] args)
     throws ParseException, ArrayIndexOutOfBoundsException, HelpException {
   super.parseArgs(cli, args);
   long tau = Long.parseLong(args[1]);
   long delay = Long.parseLong(args[2]);
   String lower_prefix =
       cli.hasOption(lowerPrefixOption)
           ? cli.getOptionValue(lowerPrefixOption)
           : LinkTrace.defaultName;
   lower_name = ReachabilityTrace.defaultName(lower_prefix, tau, delay);
   String upper_prefix =
       cli.hasOption(upperPrefixOption)
           ? cli.getOptionValue(upperPrefixOption)
           : lower_prefix + "_upper";
   upper_name = ReachabilityTrace.defaultName(upper_prefix, tau, delay);
 }