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I don't know why the code keeps sending jobs. The code is:

backend = service.backend('ibmq_qasm_simulator')
parameters = np.array([0.3,0.4])
p = parameters.size // 2

options = Options(optimizzation_level=2)
sampler = Sampler(session=backend, options=options)
qaoa = QAOA(sampler = sampler, optimizer = ADAM(), reps=p, initial_point = parameters)

result = qaoa.compute_minimum_eigenvalue(qubit_op)

What am I missing?

EDIT: qubit_op comes from:

def get_operator(weight_matrix: np.ndarray) -> tuple[SparsePauliOp, float]:
    num_nodes = len(weight_matrix)
    pauli_list = []
    coeffs = []
    shift = 0

    for i in range(num_nodes):
        for j in range(i):
            if weight_matrix[i, j] != 0:
                x_p = np.zeros(num_nodes, dtype=bool)
                z_p = np.zeros(num_nodes, dtype=bool)
                z_p[i] = True
                z_p[j] = True
                pauli_list.append(Pauli((z_p, x_p)))
                coeffs.append(-0.5)
                shift += 0.5

    for i in range(num_nodes):
        for j in range(num_nodes):
            if i != j:
                x_p = np.zeros(num_nodes, dtype=bool)
                z_p = np.zeros(num_nodes, dtype=bool)
                z_p[i] = True
                z_p[j] = True
                pauli_list.append(Pauli((z_p, x_p)))
                coeffs.append(1.0)
            else:
                shift += 1

    return SparsePauliOp(pauli_list, coeffs=coeffs), shift

qubit_op, offset = get_operator(weight_matrix)
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  • $\begingroup$ Hi and welcome to Quantum Computing SE. How many variables do you have? How many jobs have been sent? $\endgroup$
    – Martin Vesely
    Apr 28 at 17:39
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    $\begingroup$ It sent almost 300 jobs before I stopped the kernel. I put only two parameters and p=1 as you can see from the code above, the graph is a 5 node weighted graph. The code is really similar to the one in: qiskit.org/documentation/tutorials/algorithms/05_qaoa.html I took the functions from there. $\endgroup$
    – Mattia Chiurco
    Apr 29 at 18:12
  • $\begingroup$ And how is you qubit_op defined? I do not see any objective function in your code. Just for you information, I run 6-variable QUBO problem on real 7-qubit processor with QAOA and around 160 iterations were needed. $\endgroup$
    – Martin Vesely
    May 1 at 7:09
  • $\begingroup$ I just started studying this topic and I didn't know that QAOA needs to send more than one job, I thought that one job was enough for all the iterations needed. I added to the question the function get_operator where qubit_op comes from. I will try to run the program whit a small graph and see what happens. $\endgroup$
    – Mattia Chiurco
    May 1 at 16:04
  • $\begingroup$ I tried with a 2-vertex graph and I had to stop the kernel manually after it reached more than 1000 jobs sent to the ibmq_qasm_simulator $\endgroup$
    – Mattia Chiurco
    May 1 at 17:03

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