How to use the libensemble.libE_manager.manager_main function in libensemble

hist = History(alloc_specs, sim_specs, gen_specs, exit_criteria, H0)

    # Launch workers here
    dtypes = {EVAL_SIM_TAG: hist.H[sim_specs['in']].dtype,
              EVAL_GEN_TAG: hist.H[gen_specs['in']].dtype}

    try:
        wcomms = [QCommThread(worker_main, dtypes=dtypes,
                              sim_specs=sim_specs,
                              gen_specs=gen_specs,
                              workerID=w+1)
                  for w in range(libE_specs['nworkers'])]
        for wcomm in wcomms:
            wcomm.run()
        persis_info, exit_flag = \
          manager_main(hist, libE_specs, alloc_specs, sim_specs, gen_specs,
                       exit_criteria, persis_info, wcomms)

    except Exception as e:
        eprint(traceback.format_exc())
        eprint("\nManager exception raised .. aborting ensemble:\n")
        eprint("\nDumping ensemble history with {} sims evaluated:\n".
               format(hist.sim_count))
        filename = 'libE_history_at_abort_' + str(hist.sim_count) + '.npy'
        np.save(filename, hist.trim_H())
        sys.stdout.flush()
        sys.stderr.flush()
    else:
        logger.debug("Manager exiting")
        print(libE_specs['nworkers'], exit_criteria)
        sys.stdout.flush()

def libE_manager(wcomms, sim_specs, gen_specs, exit_criteria, persis_info,
                 alloc_specs, libE_specs, hist,
                 on_abort=None, on_cleanup=None):
    "Generic manager routine run."

    if 'out' in gen_specs and ('sim_id', int) in gen_specs['out']:
        logger.manager_warning(_USER_SIM_ID_WARNING)

    try:
        persis_info, exit_flag, elapsed_time = \
            manager_main(hist, libE_specs, alloc_specs, sim_specs, gen_specs,
                         exit_criteria, persis_info, wcomms)
        logger.info("libE_manager total time: {}".format(elapsed_time))

    except ManagerException as e:
        _report_manager_exception(hist, persis_info, e)
        if libE_specs.get('abort_on_exception', True) and on_abort is not None:
            on_abort()
        raise
    except Exception:
        _report_manager_exception(hist, persis_info)
        if libE_specs.get('abort_on_exception', True) and on_abort is not None:
            on_abort()
        raise
    else:
        logger.debug("Manager exiting")
        logger.debug("Exiting with {} workers.".format(len(wcomms)))

def libE_manager(wcomms, sim_specs, gen_specs, exit_criteria, persis_info,
                 alloc_specs, libE_specs, hist,
                 on_abort=None, on_cleanup=None):
    "Generic manager routine run."

    if 'out' in gen_specs and ('sim_id', int) in gen_specs['out']:
        logger.manager_warning(_USER_SIM_ID_WARNING)

    try:
        persis_info, exit_flag, elapsed_time = \
            manager_main(hist, libE_specs, alloc_specs, sim_specs, gen_specs,
                         exit_criteria, persis_info, wcomms)
        logger.info("libE_manager total time: {}".format(elapsed_time))

    except ManagerException as e:
        report_manager_exception(hist, persis_info, e)
        if libE_specs.get('abort_on_exception', True) and on_abort is not None:
            on_abort()
        raise
    except Exception:
        report_manager_exception(hist, persis_info)
        if libE_specs.get('abort_on_exception', True) and on_abort is not None:
            on_abort()
        raise
    else:
        logger.debug("Manager exiting")
        logger.debug("Exiting with {} workers.".format(len(wcomms)))

CalcInfo.make_statdir()

    exit_flag = []
    hist = History(alloc_specs, sim_specs, gen_specs, exit_criteria, H0)

    # Launch workers here
    dtypes = {EVAL_SIM_TAG: hist.H[sim_specs['in']].dtype,
              EVAL_GEN_TAG: hist.H[gen_specs['in']].dtype}

    try:
        wcomms = [QCommProcess(worker_main, dtypes, sim_specs, gen_specs, w)
                  for w in range(1, libE_specs['nworkers']+1)]
        for wcomm in wcomms:
            wcomm.run()
        persis_info, exit_flag = \
          manager_main(hist, libE_specs, alloc_specs, sim_specs, gen_specs,
                       exit_criteria, persis_info, wcomms)

    except Exception:
        eprint(traceback.format_exc())
        eprint("\nManager exception raised .. aborting ensemble:\n")
        eprint("\nDumping ensemble history with {} sims evaluated:\n".
               format(hist.sim_count))
        filename = 'libE_history_at_abort_' + str(hist.sim_count) + '.npy'
        np.save(filename, hist.trim_H())
        sys.stdout.flush()
        sys.stderr.flush()
    else:
        logger.debug("Manager exiting")
        print(libE_specs['nworkers'], exit_criteria)
        sys.stdout.flush()