How can I resolve this get_count issue from running multiple circuits?

Question

I'm running a couple of circuits at the same time using an array of variables. However, I met an issue regarding accessing the counts. Here's part of the code I have:

probsu = []
circuits = []

for i in range(len(Variable)):
    circuit =  QuantumCircuit(qrz,crz)
    circuit =  qc(Variable[i])
    circuits.append(circuit)
    prob = counts['1001'] / sum(counts.values()) **Issue here**
    probsu.append(prob)                          **Issue here**

circuits = transpile(circuits, backend=backend) 
job_manager = IBMQJobManager()
MyExperiments = job_manager. run(circuits, backend=backend, name='MyExperiment')
results = MyExperiments.results()
counts = results.get_counts(circuit)

I'm not able to get the counts since the line is referenced before the definition in the last line. However, there will be similar issues pop up if I remove the bottom lines before the for loop. How can I resolve this issue? Thanks:)

Answer 1

You mean something like this?

%matplotlib inline
# Importing standard Qiskit libraries
from qiskit import QuantumCircuit, QuantumRegister,  IBMQ, ClassicalRegister
from qiskit.circuit import QuantumCircuit, ParameterVector
from qiskit.compiler import transpile, assemble
from qiskit.providers.ibmq.managed import IBMQJobManager
from qiskit.visualization import *
provider = IBMQ.load_account()
backend = provider.get_backend('ibmq_qasm_simulator')

def qc(Variable):
    var_form = QuantumCircuit(2,2)
    var_form.ry(Variable,0)
    var_form.cx(0,1) 
    var_form.h(1)
    var_form.measure([0,1],[0,1])
    return var_form

Variables = [1,2,3,4,5]
circuits = []
for i in range(len(Variables) ):
    circuit =  QuantumCircuit(2,2)
    circuit = qc(Variables[i])
    circuits.append( circuit   )


circuits = transpile(circuits, backend=backend) 
job_manager = IBMQJobManager()
MyExperiments = job_manager.run(circuits, backend=backend, shots =1000, name='MyExperiment')
results = MyExperiments.results()

probsu = []
for i in range(len(Variables) ):
    prob = results.get_counts(i)['11']/sum( results.get_counts(i).values() ) 
    probsu.append(prob) 
print('probability of getting |11> at each circuit:', probsu)

which generate the output:

probability of getting |11> at each circuit: [0.121, 0.33, 0.458, 0.417, 0.178]

the output above corresponds to the probabilities of reading out $|11\rangle$ on each of the 5 circuits... You can modify this circuit to your purpose... as this is only an example.