Monitor: for better collecting network status

Monitor is a virtual entity to collect network status for better analysis. It can collect network status before the simulation starts, after the simulation finishes, periodically, or when be triggered by a serial of events. It can be initiated by the following input parameters:

• name, the name of this monitor

• network, a optional input parameter, a QuantumNetwork object.

from qns.entity.Monitor.monitor import Monitor

monitor = Monitor(name="monitor_1", network = None)

Users should instruct monitors how to collect the data by providing a calculate function. They can use the method add_attribution to add a new watching data. The first parameter is the attribution’s name (the column’s name in pandas), and the second parameter is the calculate function calculate_func. This function will be called whenever the monitor is triggered. The input of calculate_func is a tuple (Simulator, QuantumNetwork, Event), so that calculate_func can get what they need from those input. The output is the calculated collecting data. Here are some examples.

def watch_send_count(simulator, network, event):
    return sp.count

def watch_recv_count(simulator, network, event):
    return rp.count

monitor.add_attribution(name="send_count", calculate_func=watch_send_count)
monitor.add_attribution(name="recv_count", calculate_func=watch_recv_count)
monitor.add_attribution(name="event_name", calculate_func=lambda s, n, e: e.__class__)

Finally, users should tell the monitor when to collect data. SimQN provides the following hooks:

# before the simulation starts
m.at_start()

# after it finishes
m.at_finish()

# at a fixed period time
m.at_period(period_time=1)

# watch every ``RecvQubitPacket`` Event
m.at_event(RecvQubitPacket)

Before the simulation start, the monitor should be installed to the simulator by install method. After the simulation finishes, users can get the collected data using get_data function. The data will be formed in a pandas.DataFrame object.

m.install(s)
s.run()
data = m.get_data()