Parallel computing options don't work for statevector_simulator backend

[SamMugel]

Informations

• Qiskit Aqua version: 0.6.2
• Python version: 3.7.6
• Operating system: Ubuntu 18.04.3 LTS

What is the current behavior?

The parallel computing backend options for the simulated device don't seem to do anything.

This issue was already pointed out here:

https://quantumcomputing.stackexchange.com/questions/9209/how-to-use-parallel-executions-of-circuits

Steps to reproduce the problem

Here is the code I ran. I observed no significant differences between runs

from qiskit import BasicAer
from qiskit.aqua import QuantumInstance
from qiskit.finance.ising import portfolio
from qiskit.finance.data_providers import RandomDataProvider
from qiskit.aqua.algorithms import VQE
from qiskit.aqua.components.optimizers import COBYLA
from qiskit.aqua.components.variational_forms import RY
import time
import matplotlib.pyplot as plt
from matplotlib import rcParams

rcParams.update({'figure.autolayout': True})

# set number of assets (= number of qubits)
num_assets = 1

# Generate expected return and covariance matrix from (random) time-series
stocks = [("TICKER%s" % i) for i in range(num_assets)]
data = RandomDataProvider(tickers=stocks)
data.run()
mu = data.get_period_return_mean_vector()
sigma = data.get_period_return_covariance_matrix()

q = 0.5  # set risk factor
budget = int(num_assets / 2)  # set budget
penalty = num_assets  # set parameter to scale the budget penalty term

qubitOp, offset = portfolio.get_operator(mu, sigma, q, budget, penalty)

backend = BasicAer.get_backend("statevector_simulator")
seed = 50

cobyla = COBYLA(maxiter=50)

def run_vqe(backend_options, max_evals_grouped):
    ry = RY(qubitOp.num_qubits, depth=3, entanglement="full")
    vqe = VQE(qubitOp, ry, cobyla, max_evals_grouped=max_evals_grouped)
    vqe.random_seed = seed

    quantum_instance = QuantumInstance(
        backend=backend,
        seed_simulator=seed,
        seed_transpiler=seed,
        backend_options=backend_options,
    )

    vqe.run(quantum_instance, backend_options=backend_options)

num_processors = 4
backend_options = {
    "no parallel": {"max_parallel_threads": 1, "max_parallel_experiments": 1, "max_parallel_shots": 1},
    "parallel shots": {"max_parallel_threads": 4, "max_parallel_experiments": 1, "max_parallel_shots": 4},
    "parallel exp": {"max_parallel_threads": 4, "max_parallel_experiments": 4, "max_parallel_shots": 1},
}

runtimes = []
for key, options in backend_options.items():
    for max_evals_grouped in (1, num_processors):
        start = time.process_time()
        run_vqe(options, max_evals_grouped)
        runtime = time.process_time() - start

        runtimes.append(runtime)

What is the expected behavior?

Suggested solutions

[woodsp-ibm]

Only the Aer simulator has those parallel options not the BasicAer simulator.

from qiskit import ~Basic~Aer ... backend = ~Basic~Aer.get_backend("statevector_simulator")