Using the QuantumDispatcher Class

A Dispatcher has 3 functions: run_and_transmit, multi_run_and_transmit, and batch_run_and_transmit. run_and_transmit takes in 3 parameters: * pre-operation: a circuit of operations to prepare a transmitted state * post-operations: a list operations to run on different devices * the number of shots to run the circuit.

run_and_transmit is intended to run a single job, while multi_run_and_transmit is intended to run multiple job. For multi_run_and_transmit the preparation operations are expected to be a list of operations, and the post operations are expected to be a list of lists. The ith element of each list corresponds to the circuit ran as the ith job. batch_run_and_transmit creates and runs all permutations of operations given to it, both pre and post transmission.

Example

Consider the scenario for measurement incompatible testing. First, we prepare the BB84 states for Alice, and Bob measures based on the input he gets, y = 0 or y = 1.

So we would like to make 2 measurements, once with Bob's input 0 and another with 1. We can instantaite a LocalDispatcher and call the method multi_run_and_transmit on this instance to accomplish this. To instantiate a LocalDispatcher, we need to feed in one device.

# Importing standard Qiskit libraries and configuring account
from qiskit import QuantumCircuit, IBMQ
# from qiskit.tools.jupyter import *
# from qiskit.visualization import *
# from qiskit.providers.ibmq.managed import IBMQJobManager

# Loading your IBM Q account(s)
provider = IBMQ.load_account()

import numpy as np

import context
from device_independent_test.quantum_communicator import LocalDispatcher

def get_bb84_state():
    qc = QuantumCircuit(4)
    qc.x(1) # create 1
    qc.h(2) # create +
    qc.x(3) # create -
    qc.h(3) # ^
    return qc

def measure_circuit(y):
    qc = QuantumCircuit(4)
    theta = -1.0*(np.pi/4 + 0.5*y*np.pi) # -pi/4 rotation for y=0, -3pi/4 rotation for y=1
    qc.u3(theta,0,0,0)
    qc.measure_all()
    return qc

# initialization for two measurements - both preparing bb84 state
pre_ops = [get_bb84_state(), get_bb84_state()]

# one test sequence with QuantumCircuit(4) + measure_circuit(0)
# and another with QuantumCircuit(4) + measure_circuit(1) 
post_ops = [
    [QuantumCircuit(4), QuantumCircuit(4)],
    [measure_circuit(0), measure_circuit(1)]
]

dispatch = LocalDispatcher([provider.get_backend('ibmq_qasm_simulator')])
counts = dispatch.multi_run_and_transmit(pre_ops, post_ops, 1000)

The function returns the list of counts of each measurement.

counts

[{'1010': 193,
  '1111': 49,
  '0110': 234,
  '0011': 30,
  '0111': 42,
  '1011': 32,
  '0010': 211,
  '1110': 209},
 {'1010': 36,
  '1111': 211,
  '0110': 37,
  '0011': 210,
  '0111': 205,
  '1011': 218,
  '0010': 40,
  '1110': 43}]